Note: Descriptions are shown in the official language in which they were submitted.
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WO 99151231 PCT/US99/06713
TITLE OF THE INVENTION
ANTAGONISTS OF GONADOTROPIN RELEASING HORMONE
BACKGROUND OF THE INVENTION
The gonadotropin-releasing hormone (GnRH), also referred
to as luteinizing hormone-releasing hormone (LHRH), is a decapeptide
that plays a key role in human reproduction. The hormone is released
from the hypothalamus and acts on the pituitary gland to stimulate the
biosynthesis and secretion of luteinizing hormone (LH) and follicle-
stimulating hormone (FSH). LH released from the pituitary gland is
primarily responsible for the regulation of gonadal steroid production in
both sexes, whereas FSH regulates spermatogenesis in males and
follicular development in females. GnR,H agonists and antagonists have
proven effective in the treatment of certain conditions which require
inhibition of LH/FSH release. In particular, GnRH-based therapies
have proven effective in the treatment of endometriosis, uterine fibroids,
polycystic ovarian disease, precocious puberty and several gonadal
steroid-dependent neoplasia, most notably cancers of the prostate, breast
and ovary. GnRH agonists and antagonists have also been utilized in
various assisted fertilization techniques and have been investigated as a
potential contraceptive in both men and women. They have also shown
possible utility in the treatment of pituitary gonadotrophe adenomas,
sleep disorders such as sleep apnea, irritable bowel syndrome,
premenstrual syndrome, benign prostatic hyperplasia, hirsutism, as
an adjunct to growth hormone therapy in growth hormone deficient
children, and in murine models of lupus. The compounds of the
invention may also be used in combination with bisphosphonates
(bisphosphonic acids) and other agents, such as growth hormone
secretagogues, for the treatment and the prevention of disturbances of
calcium, phosphate and bone metabolism, in particular, for the
prevention of bone loss during therapy with the GnRH antagonist, and
in combination with estrogens, progesterones, antiestrogens,
antiprogestins and/or androgens for the prevention or treatment of bone
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loss or hypogonadal symptoms such as hot flashes during therapy with
the GnRH antagonist.
Additionally, a compound of the present invention may be
co-administered with a 5a-reductase 2 inhibitor, such as finasteride or
epristeride; a 5a-reductase 1 inhibitor such as 4,7b-dimethyl-4-aza-5a
cholestan-3-one, 3-oxo-4-aza-4,7b-dimethyl-16b-(4-chlorophenoxy)-5a-
androstane, and 3-oxo-4-aza-4,7b-dimethyl-16b-(phenoxy)-5a-androstane
as disclosed in WO 93/23420 and WO 95/11254; dual inhibitors of 5a-
reductase 1 and 5a-reductase 2 such as 3-oxo-4-aza-17b-(2,5-
trifluoromethylphenyl-carbamoyl)-5a-androstane as disclosed in WO
95/07927; antiandrogens such as flutamide, casodex and cyproterone
acetate, and alpha-1 blockers such as prazosin, terazosin, doxazosin,
tamsulosin, and alfuzosin.
Further, a compound of the present invention may be
used in combination with growth hormone, growth hormone releasing
hormone or growth hormone secretagogues, to delay puberty in growth
hormone deficient children, which will allow them to continue to gain
height before fusion of the epiphyses and cessation of growth at puberty.
Further, a compound of the present invention may be used
in combination or co-administered with a compound having luteinizing
hormone releasing activity such as a peptide or natural hormone or
analog thereof. Such peptide compounds include leuprorelin,
gonadorelin, buserelin, triptorelin, goserelin, nafarelin, histrelin,
deslorelin, meterlin and recirelin.
Additionally, a compound of the present invention may be
used as described in U.S. Patent No. 5,824,286 which discloses the
administration of peptide GnRH antagonists such as Antide and azaline
B to premenopausal women to enhance the readability of
mammographic film relative to a mammogram effected in the absence
of the administration.
Current GnRH antagonists are GnRH-like decapeptides
which are generally administered intravenously or subcutaneously
presumably because of negligible oral activity. These have amino
acid substitutions usually at positions one, two, three, six and ten.
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Non-peptide GnRH antagonists offer the possible
advantage of oral adminstration. Non-peptide GnRH antagonists have
been described in European Application 0 219 292 and in De, B. et al.,
J. Med. Chem., 32, 2036-2038 ( 1989), in WO 95/28405, WO 95/29900 and
EP 0679642 all to Takeda Chemical Industries, Ltd.
Substituted indoles known in the art include those
described in the following patents and patent applications. US Patent
No. 5,030,640 discloses alpha-heterocyclic ethanol aminoalkyl indoles
which are potent 13-agonists. US Patent No. 4,544,663 discloses
indolamine derivatives which are allegedly useful as male anti-fertility
agents. WO 90/05721 discloses alpha-amino-indole-3-acetic acids useful
as anti-diabetic, anti-obesity and anti-atherosclerotic agents. French
patent 2,181,559 discloses indole derivatives with sedative, neuroleptic,
analgesic, hypotensive, antiserotonin and adrenolytic activity. Belgian
patent 879381 discloses 3-aminoalkyl-1H-indole-5-thioamide and
carboxamide derivatives as cardiovascular agents used to treat
hypertension, Raynaud's disease and migraine. U.S. Patent Nos.
5,756,507, 5,780,437 and 5,849,764 also disclose substituted arylindoles as
non-peptide antagonists of GnRH.
SUMMARY OF THE INVENTION
The present invention relates to compounds which are
non-peptide antagonists of GnRH which can be used to treat a variety of
sex-hormone related conditions in men and women, to methods for their
preparation, and to methods and pharmaceutical compositions
containing said compounds for use in mammals.
Because of their activity as antagonists of the hormone
GnRH, the compounds of the present invention are useful to treat a
variety of sex-hormone related conditions in both men and women.
These conditions include endometriosis, uterine fibroids, polycystic
ovarian disease, hirsutism, precocious puberty, gonadal steroid-
dependent neoplasias such as cancers of the prostate, breast and
ovary, gonadotrophe pituitary adenomas, sleep apnea, irritable bowel
syndrome, premenstrual syndrome and benign prostatic hypertophy.
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They are also useful as an adjunct to treatment of growth hormone
deficiency and short stature, and for the treatment of systemic lupus
erythematosis. Further, the compounds of the invention may be useful
in in vitro fertilization and as contraceptives. The compounds may also
be useful in combination with androgens, estrogens, progesterones,
antiestrogens and antiprogestogens for the treatment of endometriosis,
fibroids and in contraception. They may also be useful in combination
with testosterone or other androgens or antiprogestogens in men as
a contraceptive. The compounds may also be used in combination
with an angiotensin-converting enzyme inhibitor such as Enalapril
or Captopril, an angiotensin II-receptor antagonist such as Losartan
or a renin inhibitor for the treatment of uterine fibroids. Additionally,
the compounds of the invention may also be used in combination with
bisphosphonates (bisphosphonic acids) and other agents, for the
treatment and the prevention of disturbances of calcium, phosphate and
bone metabolism, in particular, for the prevention of bone loss during
therapy with the GnRH antagonist, and in combination with estrogens,
progesterones and/or androgens for the prevention or treatment of bone
loss or hypogonadal symptoms such as hot flashes during therapy with
the GnRH antagonist.
Additionally, a compound of the present invention may be
co-administered with a 5a-reductase 2 inhibitor, such as finasteride or
epristeride; a 5a-reductase 1 inhibitor such as 4,7b-dimethyl-4-aza-5a-
cholestan-3-one, 3-oxo-4-aza-4,7b-dimethyl-16b-(4-chlorophenoxy)-5a-
androstane, and 3-oxo-4-aza-4,7b-dimethyl-16b-(phenoxy)-5a-androstane
as disclosed in WO 93/23420 and WO 95/11254; dual inhibitors of 5a-
reductase 1 and 5a-reductase 2 such as 3-oxo-4-aza-17b-(2,5-
trifluoromethylphenyl-carbamoyl)-5a-androstane as disclosed in
WO 95/07927; antiandrogens such as flutamide, casodex and cyproterone
acetate, and alpha-1 blockers such as prazosin, terazosin, doxazosin,
tamsulosin, and alfuzosin.
Further, a compound of the present invention may be
used in combination with growth hormone, growth hormone releasing
hormone or growth hormone secretagogues, to delay puberty in growth
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hormone deficient children, which will allow them to continue to gain
height before fusion of the epiphyses and cessation of growth at puberty.
Further, a compound of the present invention may be used
in combination or co-administered with a compound having luteinizing
hormone releasing activity such as a peptide or natural hormone or
analog thereof. Such peptide compounds include leuprorelin,
gonadorelin, buserelin, triptorelin, goserelin, nafarelin, histrelin,
deslorelin, meterlin and recirelin.
Additionally, a compound of the present invention may be
used as described in U.S. Patent No. 5,824,286 which discloses the
administration of peptide GnRH antagonists such as Antide and azaline
B to premenopausal women to enhance the readability of
mammographic film relative to a mammogram effected in the absence
of the administration.
DETAILED DESCRIPTION OFTHE INVENTION
The present invention relates to compounds of the general
formula
R2
X8 (CR R )-~N (A)-R'
i 9 9a m
R7 \' ~ ( Rioa
C.
~N N
I
Rs Ro I /.-.\.J Rs
R5 R4
wherein
A is C1-C6 alkyl, substituted C1-Cg alkyl, Cg-C7 cycloalkyl,
substituted C3-C7 cycloalkyl, Cg-Cg alkenyl, substituted
C3-Cg alkenyl, C3-Cg alkynyl, substituted C3-C6 alkynyl,
C1-C6 alkoxy, or CO-C5 alkyl-S(O)n-CO-C5 alkyl, CO-C5 alkyl-
O-CO-C5 alkyl, CO-C5 alkyl-NRlg-CO-C5 alkyl where Rlg and
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the Cp-C5 alkyl can be joined to form a ring,
or a single bond.
Rp is hydrogen, C1-Cg alkyl, substituted C1-Cg alkyl, wherein the
substituents are as defined below; aryl, substituted aryl,
aralkyl or substituted aralkyl, wherein the substituents are
as defined for Rg,'R4 and R5.
Rl is
~N Z~ ~N Z~ ~N Z,
I I R13 I ~~ R13 .~~ ~'~"', ~~ R13
R14 R15 R14 R15 R14 R15
~N Z~ N ~ Z~1 N ~ Z1
"I ! R13 ~~~ R13
~~ ~ ~N /~ ~ /~~ N
/~~
R14 R13 R14 R15 R14 R15
R14~, Z
Z, Z,
,"", N ~ I N R ." N . I N '"~'~'~ I ~ R 13
13 t~~ N
/~~ N
R14 R15 R14 R13 R15
R1~, Z R14~. Z. R14~. Z.
1
.."""~~~~~" R13 .,~.~~~~~ I ~ R ."..".;."". I
N ~~ N N~~ ~ 13 N ~~ N
R15 R15 R13
Z / Z ~ Z N
I ~ R13 '~~~ ~ ~'' I ~ R13 ,.w..i .... I ~ R13
R/~N~ N R ~N~
14 R15 14 R15 14 R15
Z
I ~ .~"N' .",. I Z~ R13 . ~N' ~ I Z~ R13
l~ l~~
N /,N~ R ,.N~ N
14 R13 R14 R15 14 R15
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z' N ~""~ Z~ ~R'."~ z .
I R13 ~.~ I i R13
l~~
R/:N~ ,N~ w
14 R15 14 R13 N N~ R15
R.RZ'N R1 ~\N~j
I ;, R13 N I~., R13 f N ~N
N~~
R15 R15 R13
~N Z~ ~~I Z ~N Z'N
I ~ R 13 ~~ R 13 '~"".w..~ ~ R 13
%.. ~ /.. ~ N %. N
R14 N R15 R14 N R15 R14 R15
~N Z~N ~N N~ R ~N I N~ R
.Nwm.a~ ~ ~ ~ I ~ 13 ~ / ~ 13
R a'N~R13 R15 \R14 R15 N R14
~N N..N Ni N1 Ni N1
~~J R13 ~ l ~ ~iJ R13 ~ ~ ( N~ R13
R15 ~ R14 R15 R14 R15 R14
N. I N NR ~ 1 R ~N N i R13
J 13 N\ ~ \~J 13 ~~ ~ ~N
R15 R14 R14 R15 R14
R5
N\\N R \. N1 ,"N,~ NiRl3
~J R13 ~ ~ ~~J R13
R14 N R14 R15 R14
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WO 99/51231
R~~ N.' i ~ R1 ~~' ~ R
~N ,nnr ~ / 13
iJ R13 ~~ ~ ~~J R13 [~/~~.N
\R14 R15 ~ R14 R14
R15~' ~ R15~~ ~,1
,n~,, I N R ,n,v I /, R 13
13 ~ ~~.N
~ R14 N R14
Z ~ Z ~%~ N
l ~ . N..~N
~ ~N ~ Ri4
Ri4 N Ri4
~ ~N~Ri3N ~N'N~ Ri3
/ yWVIM/'
Z , Z %~ N
~N~ N~ ~N Ri4
N
~N~N~yRi3 ~N,N/Ri3 N~/Ris
~ N R%N~ ~%~N,
Ri4 i4 R14
NnN~/Ri3 ~N-NyRi3 ~~ ~N,
' N N/~ l/ ~Z
R 4_ Ri4 Ri4N
~~Ri~ ~N~/Ri3 ~N~yNi3
..,.."""",.
Z
.~ N N%
N. ~/ N%
R 4 Ri4 Ri4
N~ Ri~ N,~Ri~ ~N~/~ 13
/ , ~ ~ , .M.,.~...r v
~M,. .~M""M~Z
RlY ~ RY ~ R a.N N
i4 4
~N'''~~Ris N~N,N/Ri3
%~_ N w ~
Ri4 Ri4
_g_
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the nitrogen atoms contained in the Rl heteroaromatic rings may exist
either as drawn or, when chemically allowed, in their
oxidized (N-~O) state;
R2 is hydrogen, C1-Cg alkyl, substituted C1-Cg alkyl, aralkyl,
substituted aralkyl, aryl, substituted aryl, alkyl -OR11,
C1-C6(~11R12)~ C1-C6(CONR11R12) or C(NR11R12)NH~
R2 and A taken together form a ring of 5-7 atoms;
R3, R4 and R5 are independently hydrogen, C 1-Cg alkyl, substituted
C1-Cg alkyl, C2-Cg alkenyl, substituted C2-C6 alkenyl, CN,
nitro, C 1-C3 perfluoroalkyl, C 1-C3 perfluoroalkoxy, aryl,
substituted aryl, aralkyl, substituted aralkyl, R110(CH2)p-,
R11C(O)O(CH2)p-, R,110C(O)(CH2)p-, -(CH2)pS(O)nR,l7~
-(CH2)pC(O)NR11R12 or halogen; wherein R17 is hydrogen,
C1-Cg alkyl, C1-C3 perfluoroalkyl, aryl or substituted aryl;
R3 and R4 taken together form a carbocyclic ring of 3-7 carbon atoms or a
heterocyclic ring containing 1-3 heteroatoms selected from
N, O and S;
Rg is hydrogen, C 1-CS alkyl, substituted C 1-C6 alkyl, aryl,
substituted aryl, C1-C3 perfluoroalkyl, CN, N02, halogen,
R110(CH2)p-, NR12C(O)R11~ ~12C(O)~11R12 or SOnRIl;
R7 is hydrogen, C1-Cg alkyl, or substituted C1-Cg alkyl, unless X
is hydrogen or halogen, then R7 is absent;
Rg is hydrogen, C(O)ORg, C(O)NR11R12~ NR11R12~ C(O)R11~
NR12C(O)Rll~ ~12C(O)~11R12~ ~125(O)2R11~
NR12S(O)2~11R12~ OC(O)R11, OC(O)NR11R12~ ORIh
SOnRll, S(O)nNR11R12~ C 1-C6 ~kYl or substituted C 1-C6
alkyl, unless X is hydrogen or halogen, then Rg is absent; or
R7 and Rg taken together form a carbocyclic ring of 3-7 atoms;
Rg and Rga are independently hydrogen, C1-Cg alkyl, substituted C1-C6
alkyl; aryl or substituted aryl, aralkyl or substituted aralkyl
when m~0; or
O
Rg and Rga taken together form a carbocyclic ring of 3-7 atoms or II
when m~0;
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Rg and A taken together form a heterocyclic ring containing 3-7 carbon
atoms and one or more heteroatoms when m~0; or
Rlp and RlOa are independently hydrogen, C1-Cg alkyl, substituted
C1-Cg alkyl, aryl, substituted aryl, aralkyl or substituted
aralkyl; or
O
R10 and RlOa taken together form a carbocyclic ring of 3-7 atoms or I~ ;
Rg and Rl0 taken together form a carbocyclic ring of 3-7 carbon atoms or
a heterocyclic ring containing one or more heteroatoms
when m~0; or
Rg and R2 taken together form a heterocyclic ring containing 3-? carbon
atoms and one or more heteroatoms when m~0; or
R10 and R2 taken together form a heterocyclic ring containing 3-? carbon
atoms and one or more heteroatoms;
R10 and A taken together form a heterocyclic ring containing 3-7 carbon
atoms and one or more heteroatoms; or
Rll and R12 are independently hydrogen , C1-Cg alkyl, substituted
C1-Cg alkyl, aryl, substituted aryl, aralkyl, substituted
aralkyl, a carbocyclic ring of 3-? atoms or a substituted
carbocyclic ring containing 3-7 atoms;
Rll and R12 taken together can form an optionally substituted ring of 3-7
atoms;
R13 is hydrogen, OH, NR?Rg, NR11S02(C1-C6 alkyl),
~11502(substituted C1-Cg alkyl), NR11S02(aryl),
~11502(substituted aryl), NR11S02(C1-Cg perfluoroalkyl);
S02NR11(C1-Cg alkyl), S02NR11(substituted C1-C6 alkyl),
s02NR,11(aryl), S02NR11(substituted aryl), S02NR11(C1-C3
perfluoroalkyl); S02NR11(C(O)C1-C6 alkyl); S02NR11(C(O)-
substituted C1-Cg alkyl); S02NR11(C(O)-aryl);
S02NR11(C(O)-substituted aryl); S(O)n(C1-Cg alkyl); S(O)n
( substituted C1-Cg alkyl), S(O)n(aryl), S(O)n(substituted
aryl), C1-C3 perfluoroalkyl, C1-C3 perfluoroalkoxy, C1-C6
alkoxy, substituted C1-CS alkoxy, COOH, halogen, N02 or
CN;
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R14 and R15 are independently hydrogen, C1-Cg alkyl, substituted C1-Cg
alkyl, C2-Cg alkenyl, substituted C2-Cg alkenyl,
CN, nitro,
C1-C3 perfluoroalkyl, C1-C3 perfluoroalkoxy, aryl,
substituted aryl, aralkyl, substituted aralkyl,
R110(CH2)p-,
R11C(O)O(CH2)p-, R110C(O)(CH2)p-, -(CH2)pS(O)nRl7~
-(CH2)pC(O)NR11R12 or halogen; wherein R17 is hydrogen,
C1-Cg alkyl, C1-C3 perfluoroalkyl, aryl or substituted
aryl;
Rlg is hydrogen, C1-Cg alkyl, substituted C1-Cg alkyl,
or
N(R11R12)~
Rlg is hydrogen, C1-Cg alkyl, substituted C1-Cg alkyl,
C(O)ORg,
C(O)NR11R12~ C(O)Rll~ S(O)nRll~
Rlg is either the definition of R13 or R14;
X is hydrogen, halogen, N, O, S(O)n, C(O), (CR11R12)p~
C2-C6
alkenyl, substituted C2-Cg alkenyl,C2-C6 alkynyl,
or
substituted C2-CS alkynyl; when X is hydrogen or
halogen,
R7 and Rg are absent; when X is O, S(O)n, C(O),
or CR11R12
only R7 or Rg is possible;
Z is O, S, or NR,11;
m is 0-3;
n is 0-2;
p is 0-4; and
the alkyl, alkenyl and alkynyl substituents are selected from
C1-Cg alkyl, C3-C7 cycloalkyl, aryl, substituted aryl, aralkyl,
substituted aralkyl, hydroxy, oxo, cyano, C1-C6 alkoxy,
fluoro, C(O)ORll~ aryl C1-Cg alkoxy, substituted aryl C1-Cg
alkoxy, and the aryl substituents are as defined for R3, R4
and R5;
or a pharmaceutically acceptable addition salt and/or hydrate thereof, or
where applicable, a geometric or optical isomer or racemic mixture
thereof.
Unless otherwise stated or indicated, the following
definitions shall apply throughout the specification and claims.
When any variable (e.g., aryl, heterocycle, R1, etc.) occurs
more than one time in any constituent or in formula I, its definition on
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each occurrence is independent of its definition at every other
occurrence. Also, combinations of substituents and/or variables are
permissible only if such combinations result in stable compounds.
The term "alkyl" is intended to include both branched- and
straight-chain saturated aliphatic hydrocarbon groups having the
specified number of carbon atoms, e.g., methyl (Me), ethyl (Et), propyl,
butyl, pentyl, hexyl, heptyl, octyl, nonanyl, decyl, undecyl, dodecyl, and
the isomers thereof such as isopropyl (i-Pr), isobutyl (i-Bu), secbutyl
(s-Bu), tertbutyl (t-Bu), isopentane, isohexane, etc.
The term "aryl" includes phenyl and naphthyl. In a
preferred embodiment, aryl is phenyl.
The term "halogen" or "halo" is intended to include
fluorine, chlorine, bromine and iodine.
As used herein, the term "composition" is intended to
encompass a product comprising the specified ingredients in the
specified amounts, as well as any product which results, directly or
indirectly, from combination of the specified ingredients in the specified
amounts
It is intended that the connecting group A can be bonded to
any of the available carbon or heteroatoms of the heteroaromatic groups
R1, including both rings of the benzo-fused heterocyclic groups and,
likewise, R13, R14~ ~d R15 can be bonded to any of the available carbon
atoms of the heteroaromatic groups Rl.
In addition, it is well known to those skilled in the art that
many of the foregoing heterocyclic groups can exist in more than one
tautomeric form. It is intended that all such tautomers be included
within the ambit of this invention.
The optical isomeric forms, that is mixtures of enantiomers
or diasteromers, e.g., racemates, as well as individual enantiomers or
diastereomers of the instant compound are included. These individual
enantiomers are commonly designated according to the optical rotation
they effect by the symbols (+) and (-), (L) and (D), ( 1) and (d) or
combinations thereof. These isomers may also be designated according
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to their absolute spatial configuration by (S) and (R), which stands for
sinister and rectus, respectively.
The individual optical isomers may be prepared using
conventional resolution procedures, e.g., treatment with an appropriate
optically active acid, separating the diastereomers and then recovering
the desired isomer. In addition, the individual optical isomers may be
prepared by asymmetric synthesis.
Additionally, a given chemical fomula or name shall
encompass pharmaceuticaly acceptable addition salts thereof and
solvates thereof, such as hydrates.
The compounds of the present invention, while effective
themselves, may be formulated and administered in the form of their
pharmaceutically acceptable addition salts for purposes of stability,
convenience of crystallization, increased solubility and other desirable
properties.
The compounds of the present invention may be
administered in the form of pharmaceutically acceptable salts. The
term "pharmaceutically acceptable salt" is intended to include all
acceptable salts Examples of acid salts are hydrochloric, nitric, sulfuric,
phosphoric, formic, acetic, trifluoroacetic, propionic, malefic, succinic,
malonic, methanesulfonic, benzenesulfonic and the like which can be
used as a dosage form for modifying the solubility or hydrolysis
characteristics or can be used in sustained release or pro-drug
formulations. Depending on the particular functionality of the
compound of the present invention, pharmaceutically acceptable salts of
the compounds of this invention include those formed from cations such
as sodium, potassium, aluminum, calcium, lithium, magnesium, zinc,
and from bases such as ammonia, ethylenediamine, N-methyl-
glutamine, lysine, arginine, ornithine, choline, N,N'-
dibenzylethylenediamine, chloroprocaine, diethanolamine, procaine, N-
benzylphenethylamine, diethylamine, piperazine, tris(hydroxymethyl)
aminomethane, and tetramethylammonium hydroxide. These salts
may be prepared by standard procedures, e.g. by reacting a free acid
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with a suitable organic or inorganic base, or alternatively by reacting a
free base with a suitable organic or inorganic acid.
Also, in the case of an acid (-COOH) or alcohol group being
present, pharmaceutically acceptable esters can be employed, e.g.
methyl, ethyl, butyl, acetate, maleate, pivaloyloxymethyl, and the like,
and those esters known in the art for modifying solubility or hydrolysis
characteristics for use as sustained release or prodrug formulations.
The compounds of the present invention may have chiral
centers other than those centers whose stereochemistry is depicted in
formula I, and therefore may occur as racemates, racemic mixtures
and as individual enantiomers or diastereomers, with all such
isomeric forms being included in the present invention as well as
mixtures thereof. Furthermore, some of the crystalline forms for
compounds of the present invention may exist as polymorphs and as
such are intended to be included in the present invention. In
addition, some of the compounds of the instant invention may form
solvates with water or common organic solvents. Such solvates are
encompassed within the scope of this invention.
The compounds of the invention are prepared according to
the following reaction schemes. All of the substituents are as defined
above unless indicated otherwise.
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~,eaction Scheme A
Rg
Pd(dppOC lrCH2C12
RR~ I I + / (CR9R9$)~o~PG~ LiCI, Na2C03,
Z R ~ o R1 ~ DMF, heat
N NH2 2a Z = H
2b Z = Et3Si
2cZ=
Ra
I
Rg sv\R4 g
R
Ri ~- (CR9R9a)m~~~ P~ R~ ~ Z
Rg ~ I I R~oRtoa Rg r I ( RtoRioe
N N Z and ~N N
H H (CR9R9a m
3b Z = Et3Si 4a Z = H
~Z= ~ 4cZ=
I , ~ R3 I ~ R3
w~
RS R4 5v R4
A preferred method for the synthesis of the substituted
tryptamines described in this invention utilizes a palladium-catalyzed
cross coupling reaction as a key step as shown in Scheme A. This 7-
azaindole synthesis involves the reaction of a suitably functionalized 3-
iodo-2-aminopyridine (1) with substituted acetylenes such as 2 in the
presence of a base like sodium carbonate, lithium chloride, and a
palladium catalyst such as (dppf)PdCl2~CH2C12. The reaction is
conducted in an inert organic solvent such as dimethylformamide at
elevated temperatures, for instance at 100°C, and the reaction is
conducted for a period of about 30 minutes to about 24 hours. A standard
workup and isolation affords the substituted isomeric indole derivatives
3 and 4, and the isomer of general formula 3 is the preferred isomer.
The acetylene utilized in this reaction may be a terminal acetylene (2a)
or be optionally substituted on the terminal carbon atom with a
substituent Z (2b, 2c). The substituent abbreviated PGl indicates an
alcohol protecting group such as a benzyl ether, tert-butyl ether or the
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like. The nature of the Z substituent determines the distribution of the ?-
azaindole isomers (3 and 4) produced in the reaction. For example, if the
substituent Z on the acetylene is a hydrogen atom then the isomer 4a is
the major product of the reaction. When the substituent Z is chosen to be
a substituted silyl group such as trimethylsilyl, triethylsilyl (as shown),
or the like, then isomer 3b is formed almost exclusively. When Z is a
substituted aryl group, then both isomers 3c and 4c may be formed and
the product mixture is separated using chromatographic or
crystallization techniques to afford the individual isomers.
If the synthesis is conducted with a silyl-substituted
acetylene 2b to produce a silyl-substituted 7-azaindole 3b, then the silyl
group is next converted to an aryl or substituted aryl group of general
formula 3c using the reactions described later in Scheme E. The 2-
arylsubstituted 7-azaindole derivatives 3c formed either directly from
arylacetylenes (2c) as shown in Scheme A or from 2-trialkylsilyl-?-
azaindoles using the method of Scheme E are then further elaborated as
described below to produce the novel ?-azaindole derivatives described in
this invention.
Reaction Scheme B
I
RB R8
\ ~N
RR ~ m-CPBA, RR r/
w s-- O
~NJ H20-CHC13 ~N
o C1CH2CH2C1,
90°C, 3 days
R$
R; X\ HCI, 100°C Re I2, Ag(CF3C02), X8
R ~ 16 h R X MeOH, rt, 3 h. R~ I
---~ i r\ -----~ R
N N ~ Rs
O ( / 9 ~N NH2 1 N NH2
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Scheme B illustrates the preparation of substituted 3-
iodo-2-aminopyridines (1) which are utilized in the Larock ?-azaindole
synthesis described in Scheme A. The 3-iodo-2-aminopyridines (1) may
be prepared in several ways described in the literature of organic
synthesis. A preferred method involves the ortho-iodination of
substituted 2-aminopyridine derivatives of general formula 9 with an
electrophilic iodination reagent such as iodine, iodine monochloride,
N-iodosuccinimide or the like. . The ortho-iodination of 2-aminopyridine
derivatives (9) as illustrated in Scheme B employs iodine and silver
trifluoroacetate in a suitable organic solvent like methanol at room
temperature and 3-iodo-2-aminopyridines of general formula 1 are
produced in high yield.
In some cases, 2-aminopyridine derivatives such as 9 may
be commercially available or alternatively they may be prepared using
methodologies known in organic chemistry. For instance, application
of methodology reported by Wachi and Terada (Wachi, K.; Terada, A.
Chem. Phacrm. Bull. 1880, 28, 465) allows the conversion of pyridines of
general formula 5 to 2-aminopyridines of general formula 9 as shown at
the top of Scheme B. In this synthetic transformation, a substituted
pyridine (5) is first converted to the corresponding N oxide (6) with a
suitable oxidant such as metes-chloroperbenzoic acid. In the next step,
the substituted pyridine N oxide 6 is reacted with 4-chloro-2,2-dimethyl-
2H-1,3-benzoxazine (7) in an inert high boiling solvent such as 1,2-
dichloroethane. An adduct initially formed in this reaction undergoes
a thermal rearrangement and the N pyridyl substituted 4-oxo-4H-1,3-
benzoxazine 8 is produced. Finally, the substituted benzoxazine 8 is
hydrolyzed with concentrated hydrochloric acid at elevated temperature
to afford the substituted 2-aminopyridines of general formula 9.
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Reaction Scheme C
NH
Ph~O~CCl3 ~ 1) n-BuLi,
(CR9R9a) off CF O (CR9R9~ o ~ ( THF, -78°C
3S ~ i ~
Ryos 2) Et3SiC1
CCh-C6H i 2
2a
(CR9R9a)
Et3Sf' 2b R toRtoe
(CRgRga)m CH i ~ X Pd(OAc)2, PPh3, ~ (CR9R9a~n~OH
+ R~ CuI, Et3N, ~ ~ R/~o\Rioa
~o Boa i
10 11 R4 R3 85°C R~~~~ 3 12
X = Br, I, OSOZCF3
NH
~ (CR9R9e)m C
Ph~O"CCI3
CF3S03H _ R~ ~ RtoRtoa
CC)4-C6Ii12 R4"~F13 2C
5 Acetylenic compounds of general structure 2 are prepared
using one of several methods depending upon the choice of the desired
substituents. When the substituents R9, R,9a, Rlo and Rloa are selected to
be hydrogen or lower alkyl groups, compounds of formula 2 may be
prepared from known acetylenic alcohols such as 3-butyn-1-ol, 4-pentyn-
10 2-0l or similar acetylenic alcohols reported in the chemical literature.
The conversion of acetylenic alcohols of general formula 10 to acetylene
derivatives of general formula 2 is shown in Scheme C. For clarity the
hydroxyl protecting group (PGl) illustrated in Scheme C is exemplified
as an O-benzyl ether. Thus, reaction of 10 with O-benzyl-2,2,2-
trichloroacetimidate in the presence of a catalytic amount of a strong
acid such as trifluoromethanesulfonic acid and in a suitable inert
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organic solvent like carbon tetrachloride at room temperature affords
after 2 to 24 hours the protected acetylenic alcohol 2a. Compounds of
formula 2a may in turn be converted to acetylenes (2b) of general
formula 2 wherein Z is a trialkylsilyl group by deprotonation of the
acetylene with a base such as n-butyllithium in an inert organic solvent
like tetrahydrofuran followed by reaction with a trialkylsilyl chloride
such as triethylchlorosilane. The deprotonation and silylation reactions
are generally conducted at low temperatures, for instance between about
-78°C and room temperature, and after standard workup and
purification a silylacetylene of formula 2b is obtained.
As previously stated, acetylenes of general formula 2c
wherein Z is an aryl or substituted aryl group, are also useful in the 7-
azaindole synthesis illustrated in Scheme A. Arylacetylenes 2c may be
prepared using a coupling reaction of cuprous acetylides derived from
acetylenic alcohols of formula 2a with various aryl halides or aryl
triflates (11). Such coupling reactions produce aryl acetylenes of general
formula 12 as shown at the bottom of Scheme C. These reactions are
generally carried out in a basic organic solvent like triethylamine at
elevated temperatures, typically between about 60°C and about
120°C, and
the coupling reaction is catalyzed by copper(I) salts such as cuprous
iodide and a palladium catalyst such as palladium acetate in
combination with triphenylphosphine. The hydroxyl group of the
arylacetylenes of general formula 12 can be protected with a suitable
protecting group such as the O-benzyl ether group shown in Scheme C,
to afford an arylacetylene (2c) of general formula 2 wherein Z is an aryl
or substituted aryl group. It is also recognized that in some cases it may
be preferable to reverse the order of the steps illustrated in Scheme C.
For instance, acetylenic alcohols (7) may be subjected to silylation or
arylation prior to the hydroxyl group protection step.
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reaction Scheme D
NH
(CRT~~ ) ~ PI~O~CCI~ /
RO 9R9a
CF SO RO (CRgRga)m
R ~oRtos
O CC C H ~ ~ LiAIH , THF
~4- 6 12 O R~oRtoa a
13 lr~
/ 1) DMSO, (COCI)2,
HO (CRgRg~", O ~ ( CH2Cl2, -SO°C
~ H (CR9R9a)m
2) Et3N
R~~oe
15 O ~o Boa
16
CBr4, PPh3,
/ /
(~9R9a)
CH2C12, rt H (CR9Rga)m ~ /
R~oR~oe
R'°R~°a n-BuLi, THF, 2a
B Br 17
-78°C to 0°C
Another useful approach for the preparation of acetylenic
compounds of general formula 2a employs an ethynylation reaction
sequence of aldehydes of general formula 16 as shown in Scheme D.
The aldehydes (16) used in the ethynylation sequence may be prepared
using various methods known in organic synthesis starting with
hydroxyesters of general formula 13, from protected hydroxyesters of
formula I4, or from alcohols related to the mono-hydroxyl protected diols
of formula 15. The choice of preferred starting material depends upon
the nature of the substituents Rg, R9a, Rlo, and R,oe selected. Scheme D
illustrates this strategy begining with the generalized hydroxy ester 13.
Protection of the hydroxyl group of 13, for instance as the O-benzylether
shown, affords a protected hydroxy ester of formula 14. The ester group
of compounds of formula 14 can then be converted to an aldehyde of
formula 16 either directly using a reagent like diisobutylaluminum
hydride in a solvent like toluene, or through a two step process. In the
two step process, reduction of the ester group with a reagent such as
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lithium aluminum hydride in tetrahydrofuran affords alcohols of
formula 15 which are then subjected to reoxidation, for instance using a
Swern-Moffatt oxidation, to afford the desired aldehydes of formula 16.
The ethynylation of aldehydes of formula 16 is accomplished
in two steps. First, aldehydes (16) are reacted with carbon tetrabromide
and triphenylphosphine in an inert organic solvent like dichloro-
methane to produce the dibromo olefins of formula 17. Next, the dibromo
olefins (17) axe treated with two equivalents of a strong base such as
n-butyllithium in tetrahydrofuran at low temperature, for instance at
about -78°C. The strong base induces dehydrohalogenation and metal-
halogen exchange to afford lithium acetylides which upon quenching
and workup afford acetylenes of general formula 2a. Alternatively, the
intermediate lithium acetylides formed in the reaction may be treated
with a trialkylsilyl chloride, such as triethylchlorosilane, to afford
silylacetylenes of general formula 2b.
Reaction Scheme E
Re R8
I X
i
RR (CR9R9a~~~~PG" R~ r\' I I (CR9R9~yPG
Rg ~o toe
R~oRloa ~N I
p SW3
ICI, AgBF4, 18
3b MeOH-THF, 0°C
(~)z \ R~ ~. (CR9R9a)~~~~~
18 + I ~ ~J R3 Rs ~ I I R~pRloa
R5 R° (dPPfjPdCl2~CHZCl2,
1 R3
19 toluene-EtOH-2M aq, NaiC03, 3c
80°C Rs Ra
The conversion of 2-silyl-substituted 7-azaindoles of general
formula 3b to 2-aryl-substituted 7-azaindoles of general formula 3c may
be accomplished in two steps as shown in Scheme E. The first step is a
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halodesilylation reaction which converts silyl-substituted 7-azaindoles of
formula 3b into 2-halo-7-azaindoles of general formula 18. Scheme E
illustrates this process using iodine monochloride so that the product
obtained is a 2-iodoindole of general formula 18. Silver tetrafluoroborate
is also employed in this example to increase the reactivity of the
halogenating reagent. It is possible to effect the halodesilylation reaction
with other electrophilic halogenating reagents such as N-bromo-
succinimide in dichloromethane which affords a 2-bromo-7-azaindole
derivative. Both 2-bromo and 2-iodo-7-azaindoles of formula 18 are
useful in the subsequent step.
The second step is a palladium-catalyzed cross coupling
reaction of the 2-halo-7-azaindole 18 with a suitable aryl or substituted
aryl organometallic reagent 19. Scheme E illustrates this process with
an aryl or substituted arylboronic acid as the organometallic reagent,
however, other organometallic reagents known to participate in
palladium-catalyzed cross-coupling reactions such as arylboronic esters
or arylstannanes may also be employed. In the example, a 2-iodo-7-
azaindole of general formula 18 is coupled with a generalized boronic
acid (19) using a catalyst such as [1,1'-bis(diphenylphosphino)ferrocene]
dichloropalladium(II) complex with dichloromethane (shown), tetrakis
(triphenylphosphine)-palladium(0) or the like. The reaction is usually
conducted at temperatures between room temperature and about 100°C,
for instance at about 80°C. This palladium catalyzed cross-coupling
reaction may be effected using various combinations of palladium
catalysts and solvent compositions known in organic chemistry, and the
selection of the conditions is made depending upon the type of organo-
metallic reagent (19) used and the identity of the substituent groups in
the two starting materials. When the organometallic reagent is a
boronic acid or boronate ester then a preferred solvent mixture consists
of toluene, ethanol and an aqueous solution of a base like cesium or
sodium carbonate. If instead the organometallic reagent 19 is an
arylstannane, then no additional base is required, and a polar aprotic
solvent such as tetrahydrofuran or dimethylformamide is employed.
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Reaction Scheme F
RB
I
(CR9Rga)m~WP~ R~ ~~ (CR9R9~m
I RtoRtoe Protect Re---~ I ( R~toe
Nip \ 7-azaindoie N N \
I v J R3 orintroduce PGz I , J R3
3~ R Rd Ro substituent 20 ~"~ -
Re
I PPh3, DEAD
Deprotect
alcohol R~ ~ (CR9R9a)~~H Zn(N3~~2pyr,
~N I N ( \ RtoRtoa imidazole, CH2C12
I I R3 rt, 1-24 h
21 ~2 R/v\/R
4
(CR9R9a~~N3 R~X\ (~9~9ayNH2
r-
RtoRtoa R~ I I ~ RtoRtoa
22 ~ Vj "~ l0% Pd/C, H2, PG2
5 a EtOH, rt 1-12 h 23 R5 R4
5 The next stage of the synthesis of the novel 7-azaindole
derivatives is illustrated in Scheme F. This sequence of reactions begins
with protection of the 7-azaindole with an amine protecting group (PG2)
to afford compounds of general formula 20. The protection step is
required to avoid competing side rections of the 2-aryltryptophol of
formula 21 (where PG2 is H) in the later conversion of compounds of
formula 21 to compounds of formula 22. The indole protection is followed
by removal of the hydroxyl protecting group (PGl) from the side chain at
the C-3 position of the 7-azaindole ring to afford compounds of general
formula 21. Finally, the hydroxyl group of 21 is converted to a primary
amine of general formula 23 which is then further functionalized as
shown below in the following schemes. The choice of an appropriate
amine protecting group (PG2) for the 7-azaindole is determined
primarily by which protecting group (PGl) is present on the hydroxyl
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group in the C-3 sidechain, and by consideration of the chemical stability
of the amine protecting group (PGl) required in the remaining steps of
the synthesis. When the hydroxyl protecting group (PGl) is an0-benzyl
ether as illustrated previously in Schemes C and D, the 7-azaindole may
be protected as a carbamate derivative such as a tert-butylcarbamate
(BOC). In this case, the BOC-protected 7-azaindole is stable under the
hydrogenolysis conditions which are used to remove the O-benzyl ether
and it may be conveniently removed at the end of the synthesis using
acidic conditions. If it is desired to synthesize compounds of formula
(I) wherein Ro is alkyl, substituted alkyl or the like, then it is possible to
introduce that substituent at this point and the use of a protecting group
and its subsequent removal is not required.
An alcohol of general formula 21 may be converted
to a primary amine of general formula 23 using a variety of methods
known in the literature of organic chemistry. The bottom of Scheme F
illustrates a process where the alcohol 21 is first converted to an azide of
general formula 22, followed by reduction to afford the amine derivative
23. The synthesis of an azide of general formula 22 from alcohols like
21 is best accomplished by performing a Mitsunobu reaction in the
presence of an appropriate azide source such as diphenylphosphoryl
azide or zinc azide pyridine complex. Scheme F illustrates the reaction
of alcohol 21 with triphenylphosphine, diethylazodicarboxylate, zinc
azide pyridine complex and a proton source such as imidazole in an
inert solvent like methylene chloride or tetrahydrofuran. The reaction is
usually conducted at room temperature for periods between 1-24 hours,
typically overnight or about 15 hours, and affords the azide of general
formula 22 in good yield. Finally, an azide of formula 22 may then be
reduced to an amine of formula 23 using one of several methods
common in organic synthesis. One preferred method is catalytic
hydrogenation in a solvent like methanol or ethanol in the presence of a
catalyst such as 10% palladium on carbon. Alternatively, azides like 22
may be reacted with triphenylphosphine to form an iminophosphorane
which upon hydrolysis with water affords the amine of formula 23 and
triphenylphophine oxide.
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Reaction Scheme G
IiO~A~
~1'( R~
O 24
EDC, HOBt,
NMM, CHZCIZ
,~)~NI~IZ I - '~2
R 1oR108 Rj ~. ~CR9R9n~N ~A~R'
Rs ~ R~oRioe O
1
Rs X A)Ri ~N N I \ Rs
R~ /~%\J 25
26
Rs Rn
Et3N, CHZCIz
The final stage of the synthesis of the novel 7-azaindole
derivatives (I) involves elaboration of the sidechain at the C-3 position of
the 7-azaindole core. One method for the completion of the synthesis is
illustrated in Scheme G. As shown, the 2-aryltryptamine (23) may be
condensed with a carboxylic acid of type 24 using the coupling reagent
1-(3-dimethylamino-propyl)-3-ethylcarbodiimide hydrochloride (EDC),
1,3-dicyclohexyl-carbodiimide (DCC) or the like with or without 1-
hydroxybenzotriazole (HOBt) and a tertiary amine base such as N
methylmorpholine (NMM), triethylamine or the like in an inert organic
solvent such as methylene chloride, chloroform, dimethylformamide, or
mixtures thereof at or near room temperature for a period of 3-24 hours
to provide the corresponding amide derivative (25). Alternatively, 2-
aryltryptamine 23 can be treated with an active ester or acid chloride
of formula 26 in an inert organic solvent such as methylene chloride,
chloroform, tetrahydrofuran, diethyl ether, or the like and a tertiary
amine base such as triethylamine, diisopropylethylamine, pyridine or
the like at a temperature of 0°-25°C for 30 minutes to 4 hours
to give
compound 25.
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WO 99/51231 PCT/US99/06713
ac 'on Scheme H
Re R2 Ra 12
Ri ~- ~CR9R9a)~N~~A)Rt Ri ~. ~CR9R9a)m~'w/~AfRt
I R/to\Rtoe,'O R6 ~ I ~ RtoRtoa
N N \ N N \
I J R3 ~ R I ~ R3
o /v\ 0 /v\ J
25 RS R4 BH3oTHF ~ R/5 \Ra
LiAIH~, THF
As shown in reaction Scheme H, the amide carbonyl of 25 can be
reduced by treatment with borane, lithium aluminum hydride, or
equivalent hydride sources in an inert organic solvent such as
tetrahydrofuran, diethyl ether, 1,4-dioxane or the like at about 25° to
about 100°C, preferably about 65°C, for a period of 1-8 hours to
give the
corresponding amine 27.
Reaction Scheme I
Is RB
H I R2
I7 ~- W9R9a)~Ny 2 ~ Rj ~. OR9R9a)m~NyA~Rt
Re ~ I I R toRtoe ~ Rs I~ I I R toRtoe
N N I \ R3 CAI-Rt \N N I \
J R3
Z3 R° 5~%~R '~A, 3 ~ sieves Ro
NaCNBH~, MeOH 29 RS R4
As shown in reaction Scheme I, the 2-aryltryptamine 23
can be modified by treatment with an aldehyde or ketone of type 28 in the
presence of a weak acid such as trifluoroacetic acid (TFA), acetic acid or
the like, with or without a dessicant such as 3~ molecular sieves or
magnesium sulfate, and a hydride source such as sodium borohydride
or sodium cyanoborohydride, in an inert organic solvent such as
methanol, ethanol, isopropanol, tetrahydrofuran, dichloromethane,
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chloroform, or mixtures thereof at a temperature of about 0° to about
25°C for a period of 1-12 hours to give the corresponding secondary or
tertiary amine derivative 29.
Reaction Scheme J
02N / NO2
\I
S02C1
2,4,6-collidine,
CH2C12
OZN / N02 R
p I
R8 Oa\1
S R
R~ ~, (CRgRg~~NH
Ro- ~ I R/~o~R~oa 1. PPh3, DEAD,
'N N \ benzene
30 Ro I/s~~J R3 HO~(A) R~ 31
R5 R4 2. n-propylamine J'
As shown in reaction Scheme J, the tryptamine 23 can be
modified using the Fukuyama modification of the Mitsunobu reaction
(Fukuyama, T.; Jow, C.-K.; Cheung, M. Tetrahedron Lett. 1995, 36, 6373-
74). The tryptamine 23 may be reacted with an arylsufonyl chloride such
as 2-nitrobenzene-sulfonyl chloride, 4-nitrobenzenesulfonyl chloride or
2,4-dinitrobenzene-sulfonyl chloride and a hindered amine base such as
2,4,6-collidine, 2,6-lutidine or the like in an inert organic solvent such as
methylene chloride to provide the corresponding sulfonamide 30. The
sulfonamides can be further modified by reaction with an alcohol of type
31 in the presence of triphenylphosphine and an activating agent such
as diethylazodicarboxylate {DEAD), diisopropylazodicaboxylate or the
like in an inert organic solvent such as benzene, toluene, tetrahydro-
furan or mixtures thereof to give the dialkylsulfonamide adduct.
Removal of a dinitrobenzenesulfonyl group is accomplished by treatment
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WO 99/51231 PCT/US99/06713
with a nucleophilic amine such as n-propylamine or the like in an inert
organic solvent such as methylene chloride to give secondary amines of
type 32. When a mono-nitrobenzenesulfonyl derivative is employed, the
removal of the sulfonamide is accomplished with a more nucleophilic
reagent such as thiophenol or mercaptoacetic acid in combination with
lithium hydroxide in DMF.
Reaction Scheme K
R~ ~~. (CR9R9a)m OH 02 / N02 1. PPh3, DEAD,
I benzene
R ~ I I Rio R~oa 0011 \
N N \ ~ g~
I 1 R + I 2. n-propylamine
pGz ~~~~~J 3 HN~~A)~R~ 33 3. Remove PG2
21 Rs Ra
Re
(CR9R9a) ~a yA ~ R1
I I Rio R.ba
~N N \
( __ i R3
32 (Ro = H)
Reaction Scheme K illustrates a method that is
complimentary to reaction Scheme J for completing the synthesis of the
novel compounds of formula (I). Scheme K also employs the Fukuyama
modification of the Mitsunobu reaction similar to that illustrated in
reaction Scheme J. However in this instance, the alcohol partner
employed is a 2-aryltryptophol of general formula 21 which has been
decribed previously in reaction Scheme F. The 2-aryltryptophol (21)
is reacted with a substituted sulfonamide of general formula 33,
triphenylphosphine and diethylazodicarboxylate in a suitable inert
organic solvent such as benzene, tetrahydrofuran, 1,4-dioxane or the
like. The reaction is generally conducted at room temperature for a
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period of 2 to 24 hours, typically overnight or for about 12-16 hours. The
product is an N,N disubstituted sulfonamide which is then separately
subjected to reaction with a base such as n-propylamine which removes
the sulfonamide substituent and furnishes a secondary amine related
to formula 32. The sulfonamides of formula 33 employed are readily
obtained from a primary amine and either 2-nitrobenzenesulfonyl
chloride, 4-nitrobenzenesulfonyl chloride or 2,4-dinitrobenzenesulfonyl
chloride (as shown) in the presence of a hindered amine base such as
2,4,6-collidine, 2,6-lutidine or the like in an inert organic solvent such as
methylene chloride. The final stage of the synthesis requires removal of
the protecting group on the 7-azaindole nitrogen atom (PG2) which
produces a compound of general formula 32 wherein Ro is a hydrogen
atom. It will be recognized by individuals skilled in the art of organic
synthesis that a preference for utilizing either the synthetic sequences
outlined in reaction Schemes J or K will be determined by the
substituents selected to be present in the compounds of formula (I).
The compounds of the present invention are useful in the
treatment of various sex-hormone related conditions in men and
women. This utility is manifested in their ability to act as antagonists
of the neuropeptide hormone GnRH as demonstrated by activity in the
following in vitro assays.
GnRH receptor binding ass~~
The ligand binding assay is conducted with the human
GnRH receptor (hGnRHR) obtained from CHO-Kl cells stably expressing
the cloned receptor. Crude membrane suspensions are prepared from
large batches of hGnRHR-CHO-K1 cells and stored as aliquots at -80°C .
The radioactive peptide ligand [5-(l2slodo-Tyr)-Buserelin] is obtained
from Woods Assays (Portland, Oregon) and has a radioactive specific
activity of 1000 Ci/mmol. The membranes and the radioligand are
diluted in assay buffer which consists of 50 mM Tris-HCl (pH 7.5), 2 mM
MgCl2 and 0.1% bovine serum albumin. The ligand binding assay is
performed at 22°C for 1 hour in 96-well polypropylene plates in a final
volume of 200 ul. Each well in the assay plate contains 0.1 nM 125I-
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WO 99/51231 PCT/US99/06713
buserelin, 10-15 ug of hGnRH receptor-membrane protein and the test
compound. Test compounds are examined over a range of
concentrations from 0.01 to 10,000 nM. The incubation is terminated by
vacuum filtration onto 96-well Packard GF/C Unifilter plates (pretreated
with 0.1% polyethyleneimine) and then washed with 2 mL of cold
phosphate buffered saline (pH ?.5). The Unifilter plates are dried prior
to addition of scintillation fluid and counting in a Packard TopCount
detector
Phos~hoinositide (PI) turnover assav
Chinese hamster ovary cell lines expressing the human
GnRH receptor functionally coupled to phospholipase C were established
and seeded at a concentration of 60,000 cells/mL/well in inositol-free F12
medium containing 10% dialyzed fetal bovine serum, 1% Pen/Strep, 2
mM glutamine, 500 ~,g/mL 6418 and 1 ~,Ci (~H)inositol in 24-well tray.
Forty-eight hours after seeding, cells were washed with 3 x 1 mL of PBS
containing 10 mM LiCl and treated with various concentrations of
GnRH antagonist for 2 hrs at 37°C before the addition of 0.5 nM
GnRH.
After incubation at 37°C for an additional 60 min, the medium was
removed and the cells were lysed with 1 mL of O.I M formic acid. The
trays were freeze-thawed once and the cell extract was applied onto a
Dowex AGl-X8 column. The column was washed with 2 x 1 mL HZO to
remove free (sH)inositol and (sH)inositol phosphates were eluted with 3 x
1 mL 2 M ammonium formate in 1M formic acid. The eluate was then
counted in a scintillation counter.
The compounds of formula I are useful in a number of
areas affected by GnRH. They may be useful in sex-hormone related
conditions, sex-hormone dependent cancers, benign prostatic hyper-
trophy or myoma of the uterus. Sex-hormone dependent cancers which
may benefit from the administration of the compounds of this invention
include prostatic cancer, uterine cancer, breast cancer and pituitary
gonadotrophe adenomas. Other sex-hormone dependent conditions
which may benefit from the administration of the compounds of this
invention include endometriosis, polycystic ovarian disease, uterine
fibroids and precocious puberty. The compounds may also be used in
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combination with an angiotensin-converting enzyme inhibitor such as
Enalapril or Captopril, an angiotensin II-receptor antagonist such as
Losartan or a renin inhibitor for the treatment of uterine fibroids.
The compounds of the invention may also be useful for
controlling pregnancy, as a contraceptive in both men and women, for
in vitro fertilization, in the treatment of premenstrual syndrome, in the
treatment of lupus erythematosis, in the treatment of hirsutism, in the
treatment of irritable bowel syndrome and for the treatment of sleep
disorders such as sleep apnea.
A further use of the compounds of this invention is as an
adjunct to growth hormone therapy in growth hormone deficient
children. The compounds may be administered with growth hormone
or a compound which increases the endogenous production or release
of growth hormone. Certain compounds have been developed which
stimulate the release of endogenous growth hormone. Peptides which
are known to stimulate the release of endogenous growth hormone
include growth hormone releasing hormone, the growth hormone
releasing peptides GHRP-6 and GHRP-1 (described in U.S. Patent No.
4,411,890, PCT Patent Pub. No. WO 89/07110, and PCT Patent Pub. No.
WO 89/07111) and GHRP-2 (described in PCT Patent Pub. No.
WO 93/04081), as well as hexarelin (J Endo~rinol Invest., 1~, (Suppl 4),
45 (1992)). Other compounds which stimulate the release of endogenous
growth hormone are disclosed, for example, in the following: U.S.
Patent No. 3,239,345; U.S. Patent No. 4,036,979; U.S. Patent No. 4,411,890;
U.S. Patent No. 5,206,235; U.S. Patent No. 5,283,241; U.S. Patent No.
5,284,841; U.S. Patent No. 5,310,737; U.S. Patent No. 5,317,017; U.S.
Patent No. 5,374,721; U.S. Patent No. 5,430,144; U.S. Patent No. 5,434,261;
U.S. Patent No. 5,438,136; EPO Patent Pub. No. 0,144,230; EPO Patent
Pub. No. 0,513,974; PCT Patent Pub. No. WO 94/07486; PCT Patent Pub.
No. WO 94/08583; PCT Patent Pub. No. WO 94/11012; PCT Patent Pub. No.
WO 94/13696; PCT Patent Pub. No. WO 94/19367; PCT Patent Pub. No.
WO 95/03289; PCT Patent Pub. No. WO 95/03290; PCT Patent Pub. No.
WO 95/09633; PCT Patent Pub. No. WO 95/11029; PCT Patent Pub. No.
WO 95/12598; PCT Patent Pub. No. WO 95/13069; PCT Patent Pub. No.
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WO 99/51231 PCT/US99/06713
WO 95/14666; PCT Patent Pub. No. WO 95/16675; PCT Patent Pub. No.
WO 95/16692; PCT Patent Pub. No. WO 95/17422; PCT Patent Pub. No.
WO 95/17423; 'e a ~, 1640-1643 (June 11, 1993); Ann. Rep. Med
Chem., x,177-186 (1993); Pioo~g Med Chem Ltrs., 4_{22), 2709-2714
(1994); and Proc Natl Acad Sci USA ~2, 7001-7005 (July 1995).
Representative preferred growth hormone secretagoues
employed in the present combination include the following:
1) N-[1(R)-[(1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin]-1'-yl)carbonyl]-2-(1H-indol-3-yl)ethyl]-2-amino-2-methyl-
propanamide;
2) N-[1(R)-[(1,2-Dihydro-1-methanecarbonylspiro[3H-indole-3,4'-
piperidin]-1'-yl)carbonyl]-2-(1H-indol-3-yl)ethyl]-2-amino-2-methyl-
propanamide;
3) N-[1(R)-[(1,2-Dihydro-1-benzenesulfonylspiro[3H-indole-3,4'-
piperidin]-1'-yl)carbonyl]-2-( 1H-indol-3-yl)ethyl]-2-amino-2-methyl-
propanamide;
4) N-[1(R)-[(3,4-Dihydro-spiro[2H-1-benzopyran-2,4'-piperidin]-1'-yl)
carbonyl]-2-{ 1H-indol-3-yl)ethyl]-2-amino-2-methylpropanamide;
5) N-[1(R)-[(2-Acetyl-1,2,3,4-tetrahydrospiro[isoquinolin-4,4'-piperidin]-
1'-yl)carbonyl]-2-(indol-3-yl)ethyl]-2-amino-2-methyl-propanamide;
6) N-[1(R)-[(1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin]-1'-yl)carbonyl]-2-(phenylmethyloxy)ethyl]-2-amino-2-
methylpropanamide;
7) N-[1(R)-[(1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin]-1'-yl)carbonyl]-2-(phenylmethyloxy)ethyl]-2-amino-2-
methylpropanamide methanesulfonate;
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8) N-[1(R)-[(1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin]-1'-yl)carbonyl]-2-(2',6'-difluorophenylmethyloxy)ethyl]-2-
amino-2-methylpropanamide;
9) N-(1(R)-[(1,2-Dihydro-1-methanesulfonyl-5-fluorospiro[3H-indole-3,4'-
piperidin] -1'-yl)carbonyl] -2-(phenylmethyl oxy)ethyl] -2-amino-2-
methylpropanamide;
10) N-[1(S)-((1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin)-1'-yl) carbonyl]-2-(phenylmethylthio)ethyl]-2-amino-2-
methylpropanamide;
11) N-[1(R)-[(1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin)-1'-yl)carbonyl]-3-phenylpropyl]-2-amino-2-methyl-
propanamide;
12) N-[1(R)-[(1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin]-1'-yl)carbonyl]-3-cyclohexylpropyl]-2-amino-2-methyl-
propanamide;
13) N-[1(R)-[(1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin)-1'-yl)carbonyl]-4-phenylbutyl]-2-amino-2-methyl-
propanamide;
14) N-[1(R)-((1,2-Dihydro-1-methanesulfonylspiro[3H-indole-3,4'-
piperidin] -1'-yl)carbonyl] -2-( 5-fluoro-1H-indol-3-yl )ethyl] -2-amino-2-
methylpropanamide;
15) N-[1(R)-[(1,2-Dihydro-1-methanesulfonyl-5-fluorospiro[3H-indole-
3,4'-piperidin]-1'-yl)carbonyl]-2-(5-fluoro-1H-indol-3-yl)ethyl)-2-amino-2-
methylpropanamide;
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16) N-[1(R)-[(1,2-Dihydro-1-(2-ethoxycarbonyl)methylsulfonylspiro-[3H-
indole-3,4'-piperidin]-1'-yl)carbonyl]-2-(1H-indol-3-yl)ethyl]-2-amino-2-
methylpropanamide;
17) N-(1(R)-[(1,2-Dihydro-1,1-dioxospiro[3H-benzothiophene-3,4'-
piperidin]-1'-yl)carbonyl]-2-(phenylmethyloxy)ethyl]-2-amino-2-
methylpropanamide;
and pharmaceutically acceptable salts thereof.
The compounds of the invention may also be used in
combination with bisphosphonates (bisphosphonic acids) and other
agents, such as growth hormone secretagogues, for the treatment and
the prevention of disturbances of calcium, phosphate and bone
metabolism, in particular, for the prevention of bone loss during therapy
with the GnRH antagonist , and in combination with estrogens,
progesterones and or androgens for the prevention or treatment of bone
loss or hypogonadal symptoms such as hot flashes during therapy with
the GnRH antagonist.
Bisphosphonates (bisphosphonic acids) are known to inhibit
bone resorption and are useful for the treatment of bone lithiasis as
disclosed in U.S. Patent 4,621,077 to Rosini, et al.
The literature discloses a variety of bisphosphonic acids
which are useful in the treatment and prevention of diseases involving
bone resorption. Representative examples may be found in the
following: U.S. Patent No. 3,251,907; U.S. Patent No. 3,422,137; U.S.
Patent No. 3,584,125; U.S. Patent No. 3,940,436; U.S. Patent No. 3,944,599;
U.S. Patent No. 3,962,432; U.S. Patent No. 4,054,598; U.S. Patent No.
4,267,108; U.S. Patent No. 4,327,039; U.S. Patent No. 4,407,761; U.S.
Patent No. 4,578,376; U.S. Patent No. 4,621,077; U.S. Patent No. 4,624,947;
U.S. Patent No. 4,746,654; U.S. Patent No. 4,761,406; U.S. Patent No.
4,922,007; U.S. Patent No. 4,942,157; U.S. Patent No. 5,227,506; U.S.
Patent No. 5,270,365; EPO Patent Pub. No. 0,252,504; and J. Org. Chem.,
36, 3843 (1971).
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The preparation of bisphosphonic acids and halo-
bisphosphonic acids is well known in the art. Representative examples
may be found in the above mentioned references which disclose the
compounds as being useful for the treatment of disturbances of calcium
or phosphate metabolism, in particular, as inhibitors of bone resorption.
Preferred bisphosphonates are selected from the group of
the following compounds: alendronic acid, etidrononic acid, clodronic
acid, pamidronic acid, tiludronic acid, risedronic acid, 6-amino-1-
hydroxy-hexylidene-bisphosphonic acid, and 1-hydroxy-
3(methylpentylamino)-propylidene-bisphosphonic acid;
or any pharmaceutically acceptable salt thereof. A particularly
preferred bisphosphonate is alendronic acid (alendronate), or a
pharmaceutically acceptable salt thereof. An especially preferred
bisphosphonate is alendronate sodium, including alendronate sodium
trihydrate. Alendronate sodium has received regulatory approval for
marketing in the United States under the trademark FOSpdVIAX~.
Additionally, a compound of the present invention may be
co-administered with a 5a-reductase 2 inhibitor, such as finasteride or
epristeride; a 5a-reductase 1 inhibitor such as 4,7(3-dimethyl-4-aza-5a
cholestan-3-one, 3-oxo-4-aza-4,?(3-dimethyl-16~i-(4-chlorophenoxy)-5a
androstane, and 3-oxo-4-aza-4,7(3-dimethyl-16(3-(phenoxy)-5a-androstane
as disclosed in WO 93/23420 and WO 95/11254; dual inhibitors of 5a-
reductase 1 and 5a-reductase 2 such as 3-oxo-4-aza-17~i-(2,5-
trifluoromethylphenyl-carbamoyl)-5a-androstane as disclosed in
WO 95/07927; antiandrogens such as flutamide, casodex and cyproterone
acetate, and alpha-1 blockers such as prazosin, terazosin, doxazosin,
tamsulosin, and alfuzosin.
Further, a compound of the present invention may be
used in combination with growth hormone, growth hormone releasing
hormone or growth hormone secretagogues, to delay puberty in growth
hormone deficient children, which will allow them to continue to gain
height before fusion of the epiphyses and cessation of growth at puberty.
Further, a compound of the present invention may be
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WO 99/51231 PCT/US99/06713
used in combination or co-administered with a compound having
luteinizing hormone releasing activity such as a peptide or natural
hormone or analog thereof. Such peptide compounds include
leuprorelin, gonadorelin, buserelin, triptorelin, goserelin, nafarelin,
histrelin, deslorelin, meterlin and recirelin.
For combination treatment with more than one active
agent, where the active agents are in separate dosage formulations, the
active agents may be administered separately or in conjunction. In
addition, the administration of one element may be prior to, concurrent
to, or subsequent to the administration of the other agent.
The pharmaceutical compositions containing the active
ingredient may be in a form suitable for oral use, for example, as tablets,
troches, lozenges, aqueous or oily suspensions, dispersible powders
or granules, emulsions, hard or soft capsules, or syrups or elixirs.
Compositions intended for oral use may be prepared according to any
method known to the art for the manufacture of pharmaceutical
compositions and such compositions may contain one or more agents
selected from the group consisting of sweetening agents, flavoring
agents, coloring agents and preserving agents in order to provide
pharmaceutically elegant and palatable preparations. Tablets contain
the active ingredient in admixture with non-toxic pharmaceutically
acceptable excipients which are suitable for the manufacture of tablets.
These excipients may be for example, inert diluents, such as calcium
carbonate, sodium carbonate, lactose, calcium phosphate or sodium
phosphate; granulating and disintegrating agents, for example, corn
starch, or alginic acid; binding agents, for example starch, gelatin or
acacia, and lubricating agents, for example, magnesium stearate,
stearic acid or talc. The tablets may be uncoated or they may be coated
by known techniques to delay disintegration and absorption in the
gastrointestinal tract and thereby provide a sustained action over a
longer period. For example, a time delay material such as glyceryl
monostearate or glyceryl distearate may be employed. They may also be
coated by the technique described in the U.S. Patent 4,256,108; 4,166,452;
and 4,265,874 to form osmotic therapeutic tablets for control release.
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Formulations for oral use may also be presented as hard
gelatin capsules wherein the active ingredient is mixed with an inert
solid diluent, for example, calcium carbonate, calcium phosphate or
kaolin, or as soft gelatin capsules wherein the active ingredient is mixed
with water or an oil medium, for example peanut oil, liquid paraffin, or
olive oil.
Aqueous suspensions contain the active material in
admixture with excipients suitable for the manufacture of aqueous
suspensions. Such excipients are suspending agents, for example
sodium carboxymethyl-cellulose, methylcellulose, hydroxy-propylmethy-
cellulose, sodium alginate, polyvinyl-pyrrolidone, gum tragacanth and
gum acacia; dispersing or wetting agents may be a naturally-occurring
phosphatide, for example lecithin, or condensation products of an
alkylene oxide with fatty acids, for example polyoxyethylene stearate, or
condensation products of ethylene oxide with long chain aliphatic
alcohols, for example heptadecaethylene-oxycetanol, or condensation
products of ethylene oxide with partial esters derived from fatty acids
and a hexitol such as polyoxyethylene sorbitol monooleate, or
condensation products of ethylene oxide with partial esters derived from
fatty acids and hexitol anhydrides, for example polyethylene sorbitan
monooleate. The aqueous suspensions may also contain one or more
preservatives, for example ethyl, or n-propyl, p-hydroxybenzoate, one or
more coloring agents, one or more flavoring agents, and one or more
sweetening agents, such as sucrose, saccharin or aspartame.
Oily suspensions may be formulated by suspending the
active ingredient in a vegetable oil, for example arachis oil, olive oil,
sesame oil or coconut oil, or in mineral oil such as liquid paraffin. The
oily suspensions may contain a thickening agent, for example beeswax,
hard paraffin or cetyl alcohol. Sweetening agents such as those set forth
above, and flavoring agents may be added to provide a palatable oral
preparation. These compositions may be preserved by the addition of
an anti-oxidant such as ascorbic acid.
Dispersible powders and granules suitable for preparation
of an aqueous suspension by the addition of water provide the active
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WO 99/51231 PC'T/US99/06713
ingredient in admixture with a dispersing or wetting agent, suspending
agent and one or more preservatives. Suitable dispersing or wetting
agents and suspending agents are exemplified by those already
mentioned above. Additional excipients, for example sweetening,
flavoring and coloring agents, may also be present.
The pharmaceutical compositions of the invention may also
be in the form of an oil-in-water emulsions. The oily phase may be a
vegetable oil, for example olive oil or arachis oil, or a mineral oil, for
example liquid paraffin or mixtures of these. Suitable emulsifying
agents may be naturally-occurring phosphatides, for example soy beans,
lecithin, and esters or partial esters derived from fatty acids and hexitol
anhydrides, for example sorbitan monooleate, and condensation
products of the said partial esters with ethylene oxide, for example
polyoxyethylene sorbitan monooleate. The emulsions may also contain
sweetening and flavouring agents.
Syrups and elixirs may be formulated with sweetening
agents, for example glycerol, propylene glycol, sorbitol or sucrose.
Such formulations may also contain a demulcent, a preservative and
flavoring and coloring agents. The pharmaceutical compositions may
be in the form of a sterile injectable aqueous or oleagenous suspension.
This suspension may be formulated according to the known art using
those suitable dispersing or wetting agents and suspending agents
which have been mentioned above. The sterile injectable preparation
may also be a sterile injectable solution or suspension in a non-toxic
parenterally-acceptable diluent or solvent, for example as a solution in
1,3-butane diol. Among the acceptable vehicles and solvents that may
be employed are water, Ringer's solution and isotonic sodium chloride
solution. In addition, sterile, fixed oils are conventionally employed as
a solvent or suspending medium. For this purpose any bland fixed oil
may be employed including synthetic mono- or diglycerides. In addition,
fatty acids such as oleic acid find use in the preparation of injectables.
Compounds of Formula I may also be administered in the
form of a suppositories for rectal administration of the drug. These
compositions can be prepared by mixing the drug with a suitable non-
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irritating excipient which is solid at ordinary temperatures but liquid at
the rectal temperature and will therefore melt in the rectum to release
the drug. Such materials are cocoa butter and polyethylene glycols.
For topical use, creams, ointments, jellies, solutions or
suspensions, etc., containing the compound of Formula I are employed.
(For purposes of this application, topical application shall include mouth
washes and gargles.)
The compounds for the present invention can be
administered in intranasal form via topical use of suitable intranasal
vehicles, or via transdermal routes, using those forms of transdermal
skin patches well known to those of ordinary skill in the art. To be
administered in the form of a transdermal delivery system, the dosage
administration will, of course, be continuous rather than intermittent
throughout the dosage regimen. Compounds of the present invention
may also be delivered as a suppository employing bases such as cocoa
butter, glycerinated gelatin, hydrogenated vegetable oils, mixtures of
polyethylene glycols of various molecular weights and fatty acid esters
of polyethylene glycol.
The dosage regimen utilizing the compounds of the
present invention is selected in accordance with a variety of factors
including type, species, age, weight, sex and medical condition of
the patient; the severity of the condition to be treated; the route of
administration; the renal and hepatic function of the patient; and the
particular compound thereof employed. A physician or veterinarian
of ordinary skill can readily determine and prescribe the effective
amount of the drug required to prevent, counter, arrest or reverse
the progress of the condition. Optimal precision in achieving
concentration of drug within the range that yields efficacy without
toxicity requires a regimen based on the kinetics of the drug's
availability to target sites. This involves a consideration of the
distribution, equilibrium, and elimination of a drug. Preferably,
doses of the compound of structural formula T useful in the method
of the present invention range from 0.01 to 1000 mg per adult human
per day. Most preferably, dosages range from 0.1 to 500 mg/day. For
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oral administration, the compositions are preferably provided in the
form of tablets containing 0.01 to 1000 milligrams of the active
ingredient, particularly 0.01, 0.05, 0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 15.0,
25.0,
50.0, 100 and 500 milligrams of the active ingredient for the
symptomatic adjustment of the dosage to the patient to be treated.
An effective amount of the drug is ordinarily supplied at a dosage
level of from about 0.0002 mg/kg to about 50 mg/kg of body weight per
day. The range is more particularly from about 0.001 mg/kg to 1
mg/kg of body weight per day.
Advantageously, the active agent of the present invention
may be administered in a single daily dose, or the total daily dosage
may be administered in dividend doses of two, three or four times
daily.
The amount of active ingredient that may be combined
with the carrier materials to produce a single dosage form will vary
depending upon the host treated and the particular mode of
administration.
It will be understood, however, that the specific dose level
for any particular patient will depend upon a variety of factors including
the age, body weight, general health, sex, diet, time of administration,
route of administration, rate of excretion, drug combination and the
severity of the particular disease undergoing therapy.
The following examples illustrate the preparation of some of
the compounds of the invention and are not to be construed as limiting
the invention disclosed herein.
AMPLE 1
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N
H
CH3
(S)-1-(N.~V Diisobutvlamino)-2-f2-(3,5-dimet ilphen.
3-f1-methyl-2-(imidazof4,5-blRyridin-6-yl)eth -1H Ry~rolo
f2.3-bl-pyridin-5 yll-~-methylnropan-1-one
Step lA: Methyl (S)-2-[3-(2-benzyloxy-1-methylethyl)-2-triethylsilyl-
~l-Rvrrolof2.3-blRyridin-5-yll-2-meth lpropanoate
A vigorously stirred suspension of methyl 2-(6-amino-5-
iodopyridin-3-yl)-2-methylpropanoate (4.61 g, 14.4 mmol), (S)-(4-
benzyloxy-3-methylbut-1-ynyl)triethylsilane (4.98 g, 17.3 mmol),
Pd(dppf)C12~CH2Cl2 (0.59 g, 0.72 mmol) LiCI (0.61 g, 14.4 mmol), Na2C03
(3.82 g, 36.0 mmol) and N,N dimethylformamide (60 mL) was degassed
via three vacuum/nitrogen ingress cycles and the resulting mixture was
heated at approximately 90°C overnight. After cooling to ambient
temperature, the reaction mixture was diluted with ethyl acetate and
filtered through celite~ washing copiously with ethyl acetate. The
filtrate was poured into water and extracted with ethyl acetate (x3). The
combined organic extract was washed with brine, dried (MgS04) and
concentrated in vacuo. The residue was purified by flash
chromatography on silica gel (gradient elution; 20-25% ethyl
acetate/hexanes as eluent) to give the title compound as a viscous pale
yellow oil (6.11 g, 95%).
Step 1B: Methyl (S)-2-[3-(2-benzyloxy-1-methylethyl)-2-iodo-1H
nvrrolo f 2.3-bl pyridin-5-vll -2-methylpropanoate
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A solution of iodine monochloride (2.83 g, 17.4 mmol) in
MeOH (25 mL) was added over approximately 0.5 h via pressure
equalizing addition funnel to a vigorously stirred mixture of methyl
(S)-2-[3-(2-benzyloxy-1-methylethyl)-2-triethylsilyl-1H pyrrolo[2,3-
b]pyridin-5-yl]-2-methylpropanoate (6.00 g, 13.4 mmol) and silver
tetrafluoroborate (3.39 g, 17.4 mmol) in MeOIi/THF (1:2; 75 mL) at 0°C.
After an additional 0.5h, the reaction was quenched with 1M Na2S203,
warmed to room temperature ,and filtered through celite~ washing
copiously with ethyl acetate. The filtrate was concentrated under
reduced pressure, poured into 1M Na2S203 and extracted with ethyl
acetate (x3). The combined organic extract was washed with brine,
dried (MgS04) and concentrated in vacuo. The residue was purified by
flash chromatography on silica gel (25% ethyl acetate/hexanes as eluent)
to give the title compound as a colourless solid (5.54 g, 84%).
Step 1C: Methyl (S)-2-[3-(2-benzyloxy-1-methylethyl)-2-(3,5-dimethyl-
phenvl)-1H Ryrrolof2,3-b],pyridin-5-~rll-2-methylpronanoate
A vigorously stirred suspension of methyl (S)-2-[3-(2-
benzyloxy-1-methylethyl)-2-iodo-1H-pyrrolo [2,3-b] pyridin-5-yI] -2-
methylpropanoate (4.00 g, 8.12 mmol), 2,5-dimethylphenylboronic acid
(1.83 g, 12.2 mmol) and Pd(dppf)C12~CH2Cl2 (0.33 g, 0.406 mmol) in
toluene/MeOH (5:2; 140 mL) was degassed via three vacuum/nitrogen
ingress cycles and the resulting mixture was heated to approximately
80°C. 1M Na2C03 (20.3 mL, 20.3 mmol) was added dropwise via syringe
and the resulting mixture maintained at reflux overnight. After cooling
to ambient temperature, the reaction mixture was diluted with ethyl
acetate and filtered through celite~ washing copiously with ethyl acetate.
The filtrate was poured into water and extracted with ethyl acetate (x3).
The combined organic extract was washed with brine, dried (MgS04)
and concentrated in vacuo. The residue was purified by flash
chromatography on silica gel (25% ethyl acetate/hexanes as eluent) to
afford the title compound as a colourless foam (3.82 g, 100%).
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Step 1D: (S)-2-[3-{2-Benzyloxy-1-methylethyl)-2-(3,5-dimethylphenyl)-
1H-p~xolof 2,3-bl Ryridin-5-y~l-2-methylDropanoicacid
A vigorously stirred suspension of methyl (S)-2-[3-(2
benzyloxy-1-methylethyl)-2-(3,5-dimethyl-phenyl)-1H-pyrrolo[2,3
b]pyridin-5-yl]-2-methylpropanoate (3.82 g, 8.12 mmol) and 2N KOH (40.6
mL, 0.081 mol) in MeOH (40 mL) was heated at 80°C for approximately 4
h. After cooling to room temperature, the reaction mixture was acidified
to pH 6 with 2N HCl and extracted with ethyl acetate (x3). The combined
organic extract was washed with brine, dried (MgS04) and concentrated
in aa~cuo. The crude 'residue was used without further purification in
the subsequent reaction.
Step lE: (S)-1-(N,N Diisobutylamino)-2-[3-(2-benzyloxy-1-methyl-
ethyl)-2-(3,5-dimethylphenyl)-1H-pyrrolo [2,3-b] pyridin-
5-yll-2-meth3il~ropa_n-1-one
PyBOP is added to a stirred mixture of (S)-2-[3-(2-benzyloxy-
1-methylethyl)-2-(3,5-dimethylphenyl)-1H-pyrrolo [2,3-b] pyridin-5-yl]-2-
methylpropanoic acid, diisobutylamine and triethylamine in CHxCl2
at ambient temperature. After approximately 12h, the reaction mixture
is poured into water/brine (1:1) and extracted with ethyl acetate. The
combined organic extract is washed with brine, dried (MgS04) and
concentrated in uacuo. The residue is purified by flash chromatography
on silica gel (gradient elution; 60-75% ethyl acetate/hexanes as eluent) to
give the title compound.
Step 1F: (S)-1-{N,N Diisobutylamino)-2-[3-(2-benzyloxy-1-methyl-
ethyl)-2-(3,5-dimethylphenyl)-1H-1-{tent-butoxycarbonyl)-
pxrrolof2 3-blpvridin-5-vll-2-methy,~propan-1-one
Di-tert-butyldicarbonate is added to stirred suspension
of (S)-1-(N,N diisobutylamino)-2-[3-(2-benzyloxy-1-methylethyl)-2-(3,5-
dimethylphenyl)-1H-pyrrolo [2,3-b] pyridin-5-yl] -2-methylpropan-1-one,
DMAP, and potassium carbonate in CHZC12 at room temperature.
After approximately 3h, the reaction mixture is poured into water and
extracted with ethyl acetate. The combined organic extract is washed
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with brine, dried (MgS04) and concentrated in vacuo. The residue is
purified by flash chromatography on silica gel (60% ethyl
acetate/hexanes as eluent) to give the title compound.
Step 1G: (S)-I-(N,N Diisobutylamino)-2-(3-(2-hydroxy-1-methyl-
ethyl)-2-(3,5-dimethylphenyl)-1H-1-(tert-butoxycarbonyl)-
p~olof2 3-bl~yridin-5-vll-2-methylDTOpan 1 one
A mixture of (S)-1-(N,lV diisobutylamino)-2-[3-(2-benzyloxy-
1-methylethyl)-2-(3,5-dimethylphenyl)-1H-1-(tert-butoxycarbonyl)
pyrrolo(2,3-b]pyridin-5-yl]-2-methylpropan-1-one and Pd(OH)2 (Pd-20%}
in glacial acetic acid/EtOH (1:1) is hydrogenated at 50 psi for about 4
days. The resulting mixture is filtered through celite~ washing
copiously with EtOH, the filtrate is evaporated in aacuo and the residue
purified by flash chromatography on silica gel (gradient elution; 75-90%
ethyl acetate/hexanes) to give the title compound.
Step 1H: (S)-1-(N,1V Diisobutylamino)-2-[3-(2-azido-1-methylethyl)-2-
(3,5-dimethylphenyl)-1H-1-(tert-butoxycarbonyl)pyrrolo-
f2 3-blRvridin-5-vll-2-methylr~ropan 1 one
DEAD is added dropwise via syringe to a stirred solution
of (S)-1-(N,1V diisobutylamino)-2-[3-(2-hydroxy-1-methylethyl)-2-(3,5-
dimethylphenyl)-1H-1-(tert-butoxycarbonyl)pyrrolo[2,3-b]-pyridin-5-yl]-
2-methylpropan-1-one, ZnNs~2py, PPh3 and iniidazole in CHZC12 at
approximately 0°C. The reaction mixture is allowed to warm to room
temperature overnight, and is then filtered through celite~ washing
copiously with CH2C12. The filtrate is poured into water and extracted
with CH2C12. The combined organic extract is washed with brine, dried
(MgS04) and concentrated in aacuo. The residue is purified by flash
chromatography on silica gel (gradient elution; 25-40% ethyl
acetate/hexanes as eluent) to give the title compound.
Step lI: (S)-1-(N,N Diisobutylamino)-2-(3-(2-amino-1-methyl-
ethyl)-2-(3,5-dimethylphenyl)-1H 1-(tent-butoxycarbonyl)-
»xolof2 3-blpyridin-5-vll-2 methylRropan 1 one
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A mixture of (S)-1-(N,N-diisobutylamino)-2-[3-(2-azido-
1-methylethyl)-2-(3,5-dimethylphenyl)-1H-1-(tert-butoxycarbonyl)-
pyrrolo[2,3-b]pyridin-5-yl]-2-methylpropan-1-one and Pd/C (Pd-10%) in
MeOH/EtOH is hydrogenated at 50 psi overnight. The resulting mixture
is filtered through celite~ washing copiously with EtOH, the filtrate is
evaporated in vaccuo and the residue purified by preparative thin layer
chromatography on silica gel (100%ethyl acetate as eluent) to give the
title compound.
Step 1J: (S)-1-(N,1V Diisobutylamino)-2-j3-(2-(2,4-dinitrobenzene-
sulfonylamino)-1-methylethyl)-2-(3,5-dimethylphenyl)-1H-1-
(tert-butoxycarbonyl)pyrrolo [2,3-b] pyridin-5-yl]-2-methyl-
~rouan-1-one
2,4-Dinitrobenzenesulfonyl chloride is added in one portion
to a stirred solution of (S)-1-(N,N-diisobutylamino)-2-j3-(2-amino-1-
methyl-ethyl)-2-(3,5-dimethylphenyl)-1H 1-(tert-butoxycarbonyl)-
pyrrolo[2,3-b]-pyridin-5-yl]-2-methylpropan-1-one and 2,4,6-collidine in
CH2C12 at approximately 0°C. After 5 min., the resulting mixture
is
warmed to ambient temperature and aged for 2h. The reaction mixture
is poured into water and extracted with ethyl acetate. The combined
organic extract is washed with brine, dried (MgS04) and concentrated
in vacuo. The residue is purified by flash chromatography on silica gel
(50% ethyl acetate/hexanes as eluent) to give the title compound.
Step 1K: (S)-6-j2-[N (5-[2-(N,N Diisobutylamino)-1,1-dimethyl-2-
oxoethyl]-2-(3,5-dimethylphenyl)-1H-1-(tert-butoxycarbonyl)-
pyrrolo[2,3-b]pyridin-3-yl]propyl) N (2,4-dinitrobenzene-
sulfonyl)] aminoethyl}-3-(2-trimethylsilylethoxymethyl)-3H-
imidazo [4.5-bl Rvridine
DEAD is added dropwise via syringe to a stirred solution
of (S)-1-(N,N-diisobutylamino)-2-[3-(2-(2,4-dinitrobenzenesulfonylamino)-
1-methylethyl)-2-(3,5-dimethylphenyl)-1H-1-(tent-butoxycarbonyl)-
pyrrolo[2,3-b]pyridin-5-yl]-2-methylpropan-1-one, 2-[3-(2-trimethylsilyl-
ethoxymethyl)-3H-imidazo[4,5-b]pyridin-6-yl]ethanol and PPh3 in
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benzene at room temperature. After approximately lh, the reaction
mixture is concentrated in uacuo and the residue is purified by flash
chromatography on silica gel (60-80% ethyl acetate/hexanes as eluent) to
give the title compound.
Step 1L: (S)-6-{2-[2-[5-[2-(N,N Diisobutylamino)-1,1-dimethyl-2-oxo-
ethyl]-2-(3,5-dimethylphenyl)-1H-1-(tent-butoxycarbonyl)-
pyrrolo [2, 3-bj pyridin-3-yl] propylamino] ethyl}-3-(2-trimethyl-
silvlethoxvmethyl )-3H-imidazo f 4, 5-bl Ryri dine
n-Propylamine is added to a stirred solution of crude
(S)-6-{2-[N (5-[2-(N,1V diisobutylamino)-1,1-dimethyl-2-oxoethyl]-2-(3,5-
dimethylphenyl)-1H-1-(tert-butoxycarbonyl)pyrrolo[2,3-b] pyridin-3-
yl] propyl)-N-(2,4-dinitrobenzenesulfonyl)] aminoethyl }-3-(2-trimethylsilyl-
ethoxymethyl)-3H-imidazo[4,5-bjpyridine in CH2C12 at room
temperature. After approximately 20 min, the volatiles are evaporated
in vacuo and the residue is purified by preparative thin layer
chromatography on silica gel ( 100% ethyl acetate as eluent) to give the
title compound.
Step 1M: (S)-1-(N,N Diisobutylamino)-2-(2-(3,5-dimethylphenyl)
3-[1-methyl-2-(imidazo [4,5-b] pyridin-6-yl)ethyl]-1H-
~rrolof 2 3-bl pyridin-5-Yll 2 methyl,~n~an 1 one
A solution of (S)-6-{2-[2-[5-[2-(N,N diisobuylamino)-1,1-
dimethyl-2-oxoethyl]-2-(3,5-dimethylphenyl)-1H-1-(tent-butoxycarbonyl)-
pyrrolo[2,3-b]pyridin-3-yl]propylamino]ethyl}-3-(2-trimethylsilyl-
ethoxymethyl)-3H-imidazo[4,5-b]pyridine in 2N HCl/EtOH (1:1) is aged
for approximately 2h at 75°C. After cooling to room temperature, the
reaction mixture is adjusted to pH 9 with 5N NaOH and extracted with
ethyl acetate. The combined organic extract is washed with brine, dried
(MgS04) and concentrated in vacuo. The residue is purified by
preparative thin layer chromatography on silica gel (100% ethyl acetate
as eluent) to give the title compound.
PREPARATION OF SYNTHETIC INTERMEDIATES
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Methyl 2-(6-amino-5-iodop3 'din 3 vl) 2 meth~pronanoate
Step A: Ethyl 2-methyl-2-(pvridin-3-yl)propanoate
A solution of ethyl-3-pyridylacetate (10.0 g, 60.5 mmol) in
THF (50 mL) was added over approximately 0.5 h via pressure equalizing
addition funnel to a stirred mixture of potassium hexamethyldisilazane
(48.3 g, 0.242 mmol) in THF (250 mL) at -20°C. After 0.5 h, MeI was
added dropwise so as to maintain the internal temperature between
-15°C to -20°C. After warming to approximately 0°C over
12h, the
reaction was quenched with saturated aqueous NH4Cl and concentrated
under reduced pressure. The residue was partitioned between ethyl
acetate and water, the organic phase separated and the aqueous phase
re-extracted with ethyl acetate (x3). The combined organic extract was
washed with brine, dried (MgS04) and concentrated in vacuo. The
residue was purified by flash chromatography on silica gel (30% ethyl
acetate/hexailes as eluent) to give the title compound as a pale yellow oil
(10.1 g, 86%).
Step B: Ethyl 2-met yl-2-(Ryridin-3-yl),propanoate N oxide
Meta-chloroperoxybenzoic acid (55%; 21.3 g, 67,9 mmol)
was added in one portion to a vigorously stirred emulsion of ethyl 2-
methyl-2-(pyridin-3-yl)propanoate and NaHC03 (17.5 g, 0.209 mmol)
in water/chloroform (1:1; 500 mL) at ambient temperature. After
approximately 12 h, the organic phase was separated and the aqueous
phase extracted with chloroform (x3). The combined oxganic extract
was washed with brine, dried (MgS04) and concentrated an vacuo. The
residue (10.9 g, 100%) was judged pure by a combination of TLC and 1H
nmr analysis and was used without further purification in the
subsequent reaction.
Step C: Ethyl 2-[6-(2,2-dimethyl-4-oxo-4H-1,3-benzoxazin-3-yl)-
wridin-3-vll-2-methylp~,o~ anoatP
A solution of 4-chloro-2,2-dimethyl-2H-1,3-benzoxazine
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(10.1 g, 51.6 mmol) and ethyl 2-methyl-2-(pyridin-3-yl)propanoate-
N-oxide (9.0 g, 43.0 mmol) in 1,2-dichloroethane (100 mL) was heated
at approximately 90°C for 3 d. After cooling to room temperature, the
solvent was evaporated under reduced pressure and the residue purified
by flash chromatography on silica gel (gradient elution; 20-25% ethyl
acetate/hexanes as eluent) to give the title compound as a pale yellow
viscous oil (14.3 g, 90%).
Step D: 2-(6-Aminopyridin-3-yl)-2-methylpropanoic acid
hydrochloride
A stirred mixture of ethyl 2-[6-(2,2-dimethyl-4-oxo-4H-1,3-
benzoxazin-3-yl)-pyridin-3-yl]-2-methylpropanoate (13.3 g, 36.1 mmol) in
concentrated HCl (50 mL) was heated at 100°C overnight. After cooling
to ambient temperature, the reaction mixture was concentrated in Uacuo
and the residue washed exhaustively with chloroform to give the title
compound as a colourless solid (6.90 g, 88%).
Step E: Methyl 2-(6-aminoRyridin-3 yl)-2-meth~lnronanoate
A solution of 2-(6-aminopyridin-3-yl)-2-methylpropanoic
acid hydrochloride (35.0 g, 0.162 mmol) and concentrated HZS04 (5 mL)
in MeOH (250 mL) was heated at reflex overnight. After cooling to
ambient temperature, the reaction was quenched cautiously with
saturated aqueous NaHC03 and concentrated in vacuo. The residue was
partitioned between ethyl acetate and water, the organic phase separated
and the aqueous phase re-extracted with ethyl acetate (~3). The
combined organic extract was washed with brine, dried (MgS04) and
concentrated in aacuo. The residue (31.6 g, 100%) was judged pure by a
combination of TLC and 1H nmr analysis and was used without further
purification in the subsequent reaction.
Step F: Methyl 2-(6-amino-5-iodo~ ' in-3-yl)-2-methylp~ronanoate
A solution of methyl 2-(6-aminopyridin-3-yl)-2-methyl-
propanoate (10.0 g, 51.5 mmol) in MeOH (50 mL) was added over
approximately 0.5 h uia pressure equalizing addition funnel to a
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vigorously stirred suspension of iodine (17.0 g, 67.0 mmol) and silver
trifluoroacetate (14.8 g, 67.0 mmol) in MeOH (200 mL) at room
temperature. After 3 h, the reaction was quenched sequentially with 1M
Na2S203 followed by saturated aqueous NaHC03. The resulting mixture
was filtered through celite~ washing copiously with ethyl acetate, the
filtrate concentrated in vacuo and the residue partitioned between ethyl
acetate and water. The organic phase was separated and the aqueous
phase was re-extracted with ethyl acetate (~3). The combined organic
extract was washed with brine, dried (MgS04) and concentrated in
vacuo. The residue was purified by flash chromatography on silica gel
(gradient elution; 35-40% ethyl acetate/hexanes as eluent) to give the title
compound as an off white solid (10.3 g, 62%).
(S7-(4-Benzvlox3r-3-meth ly but-1-vnyl)triethylsilane
Step AA: Methvl (.S')-3-benzvloxv-2-methy ropanoate
An oven dried 1 L single-necked round bottom flask was
equipped with a magnetic stir bar and then charged sequentially with
15.948 g (0.135 mol) of (R)-(-)-methyl-3-hydroxy-2-methylpropanoate,
carbon tetrachloride (150 mL), cyclohexane (300 mL), and 35.796 g (0.142
mol) of benzyl 2,2,2-trichloroacetimidate. Trifluoromethanesulfonic acid
(0.8 mL; 9.0 mmol) was added to the solution and the resulting mixture
was stirred for 16 h at room temperature under an N2 atmosphere. The
reaction mixture was then filtered and the filtrate concentrated in
vacuo. The residue was redissolved in 150 mL EtOAc and extracted with
saturated aqueous Na.HC03 (1x100 mL). The organic layer was washed
with saturated NaCI, dried (MgS04), filtered and evaporated. The
residual oil was purified on a silica gel flash chromatography column
eluted with 10% EtOAc-hexane. The purified fractions were combined
and evaporated in vacuo to afford 20.787 (74%) of the title compound as a
colorless oii.
MS (CI): mle = 209 (M+1).
Step BB: (S7-3-Benzyl~xy-2-meth,~propan-1-of
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An oven dried three-necked 2 L round bottom flask
was equipped with a mechanical stirrer, a reflux condenser and a
500 mL constant pressure addition funnel. The flask was charged
with a solution of 62.252 g (0.299 mol) of methyl (S)-3-benzyloxy-2-
methylpropanoate in 600 mL of anhydrous THF, and a 1.0 M solution of
lithium aluminum hydride (300 mL; 0.3 mol) was transferred into the
dropping funnel via a cannula. Stirring was started and the lithium
aluminum hydride solution was added over 45 minutes to the reaction
under an N2 atmosphere while the temperature of the reaction mixture
was maintained between 25-30°C using an external ice-water bath. After
the addition was complete, the reaction was stirred an additional 6 h at
room temperature at which point TLC analysis (20% EtOAc-hexane)
indicated complete reaction. The reaction mixture was then cooled with
an external ice-water bath and quenched by serial addition of 11.4 mL
water, 11.4 mL of 15% aqueous NaOH, and 34.2 mL water. The reaction
mixture was then filtered, the solids were washed with EtOAc, the
filtrate and washings were combined and evaporated in vaccuo. The
residue was redissolved in EtOAc, washed with 10% aqueous NaHS04,
saturated NaCI, dried (MgS04), filtered and evaporated. The residue
was purified by Kugelrohr distillation to afford 47.67 g (89%) of the title
compound as a colorless oil.
MS (CI): mle = 181 (M+1).
Step CC: (S7-3-Benz~xv-2-methylprouanal
An oven dried three-necked 2 L round bottom flask was
equipped with a mechanical stirrer, a thermometer, an NZ inlet, and
a septum. The flask was charged with 24.050 g (0.189 mol) of oxalyl
chloride and 425 mL CH2C12. The reaction mixture was stirred under an
N2 atmosphere and cooled to -78°C with an external dry ice-acetone
bath.
A solution of methyl sulfoxide (29.607 g; 0.379 mol) in 85 mL CH2C12 was
then added over 5 min to the reaction mixture via cannula. After the
adition, the reaction was stirred an additional 5 min and then a solution
of 31.048 g (0.172 mol) of (S)-3-ben~yloxy-2-methylpropan-1-of in 170 mL
CH2C12 was added via cannula. When the second addition was
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completed the reaction mixture was stirred for 15 min at -?8°C then
111.32 g (0.861 mol) of N,N diisopropylethylamine was added via syringe.
The reaction mixture was stirred an addition 15 min at -78°C, the
cooling
bath was removed and the reaction was allowed to warm. When the
internal temperature had reached -15°C, 350 mL of a 10% aqueous
NaHS04 solution was slowly added and the mixture was transferred
to a separatory funnel. The organic layer was separated, washed with
aqueous NaHS04 (2x250 mL), saturated NaCI, dried (MgS04), filtered
and evaporated. The residue was used immediately in the next step
without further purification.
Step DD: (S)-4-Benzyloxy-1,1-dibromo-3-methylbutene
An oven dried three-necked 2 L round bottom flask was
equipped with a mechanical stirrer, a thermometer, an N2 inlet,
and a septum. The flask was charged with 180.71 g (0.689 mol) of
triphenylphosphine and 925 mL of CH2C12. The reaction mixture was
stirred under an NZ atmosphere and cooled to 0-5°C with an external ice-
water bath. The septum was then removed and 114.25 g (0.344 mol) of
carbon tetrabromide was added in portions through the open neck of the
flask at a rate that maintained the temperature of the reaction mixture
below 20°C. After the addition was complete the reaction was stirred
for
1 h and then a solution of the (S)-3-benzyloxy-2-methylpropanal from the
previous step dissolved in 150 mL of CH2C12 was added via cannula over
a 5 min period. The reaction mixture was stirred under N2 for an
additional 1 h and allowed to warm to room temperature. A separate
10 L three-necked round bottom flask was equipped with a mechanical
stirrer and charged with 4 L of hexane. The stirrer was started and the
crude reaction mixture was introduced as a slow stream which resulted
in formation of a granular precipitate. After the transfer was complete
the reaction mixture was filtered and the solids were carefully washed
with hexane. The filtrate was evaporated in vacuo and additional solids
were deposited. The residue was resuspended in hexane, filtered and
the filtrate reevaporated. The resulting oil was purified by Kugelrohr
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distillation to afford 46.54 g (81% for two steps) of the title compound as a
colorless oil.
Step EE: (f7-(4-benzyloxy-3-methXlbut-1-ynvl)trieth~,~lsilane
An oven dried 100 mL single-necked round bottom flask was
equipped with a magnetic stir bar and a septum then charged with 5.171
g (15.5 mmol) of (S)-4-benzyloxy-1,1-dibromo-3-methylbutene and 20 mL
of anhydrous THF. The reaction mixture was stirred at -78°C under an
Nz atmosphere and 12.4 mL of a 2.5 M solution of n-butyllithium (31.0
mmol) was added dropwise via syringe over 15 min. The reaction
mixture was stirred at -78°C for an additional 1 h, then quenched with
10% aqueous NaHS04 and extracted into EtOAc. The organic layer was
washed with water (3x25 mL), sturated NaCI, then dried (MgS04),
filtered, and evaporated. The residue was purified by Kugelrohr
distillation to afford 3.999 g (90%) of the title compound as a colorless oil.
2-f 3-(2-Trimeth~ilsil~ethox~met-h~
-3H imidazof4,5-blpyriain-6-yll-ethanol
Step AA.A: 2-Amino-5-bromo-3-nitro~vridine
Sulfuric acid (290 mL) was cooled to 0 °C, followed by the
slow addition of 2-amino-5-bromopyridine (50 g, 289 mmol). Nitric acid
( 15 mL) was added dropwise over 30 min with the aid of a pressure-
equalized dropping funnel. After 90 min at 0 °C, the reaction mixture
was heated to 75 °C for 2 h. After cooling to ambient temperature, the
reaction mixture was poured into 1500 mL of ice-water and neutralized
to pH 8 with 50% NaOH (w/w). The precipitate formed was collected on a
fritted funnel, washed with 1000 mL cold water, and dried in vacuo ,
which provided 39.7 g of the title compound (63% yield).
Step BBB: 5-Bromo-2.3-diaminopyridine
2-Amino-5-bromo-3-nitropyridine (3.5 g, 16.1 mmol) was
combined with FeCl3 ~ 6H20 (0.217 g, 0.8 mmol) and activated charcoal
(1.6 g) to which dry methanol (160 mL) was added. The mixture was
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heated to 70 °C for 10 min, cooled to ambient temperature followed by
the
dropwise addition of hydrazine (2.57 g, 80.3 mmol) over 5 min. Heating
was resumed and the reaction was maintained at 70 °C for 2 h. After
cooling to ambient temperature, the reaction contents were filtered
through a pad of celite~, eluted with methanol followed by removal of the
solvent in vacuo. The residue was dissolved in ethyl acetate and washed
with H20, brine, dried (Na2S04), filtered, concentrated in vacuo, and the
crude reside was purified by flash chromatography on silica gel using a
gradient elution (10, 20, 40, 60, and 80% ethyl acetate/hexanes).
According to this procedure, 2.8 g (93% yield) of the title compound was
obtained.
Step CCC: 8-BromoiriiidazoRyridine
5-Bromo-2,3-diaminopyridine (4.87 g, 26 mmol) was
dissolved in triethyl orthoformate ( 150 mL) and 3 drops of concentrated
hydrochloric acid followed by heating to reflux for 50 h. After cooling to
ambient temperature, the reaction mixture was poured into hexanes
and the precipitate formed was collected by filtration. The solids were
diluted with H20 and basified to pH 10 with 1.25 N NaOH. The aqueous
layer was extracted three times with ethyl acetate The combined organic
extracts were washed with brine, dried (Na2S04), filtered and
concentrated in vaccuo. The crude residue was purified by silica gel
chromatography using 95:5 CH2C12-(10% NH40H-MeOH) as the eluent.
Following this protocol, 3.1 g (60% yield) of the title compound was
obtained.
Step DDD: 6-Bromo-3-(2-trimethysilylethoxymethyl) -3H-imidazo
I4.5-bl-Rvridine
5-Bromoimidazopyridine (3.0 g, 15.1 mmol) was dissolved in
dry N, N dimethylformamide (50 mL) and cooled to 0 °C, at which time a
60% oil dispersion of NaH (0.667 g, 16.? mmol) was added in portions
over 10 min. After 15 min at 0 °C, the reaction was allowed to warm to
ambient temperature for an additional 90 min. To the homogeneous
solution was added dropwise 2-(trimethylsilyl)ethoxymethyl chloride
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(SEM-C1, 3.03 g, 18.2 mmol). The reaction was maintained at ambient
temperature for 40 h, at which time the mixture was poured into ice-
water. The aqueous layer was extracted with diethyl ether 3 times, and
the combined organic extracts were washed with brine, dried (MgS04),
filtered, and concentrated to dryness in vacuo. The crude residue was
loaded onto a silica-gel column and eluted with ethyl acetate/ hexane (20,
30, to 40 %). According to this procedure, 2.55 g (52% yield) of the title
compound was obtained.
Step EEE: 6-Ethenyl-3-(2-trimethysilylethoxymethyl)-3H-imidazo-
[4.5-bl -Ryridine
To a solution of 6-bromo-3-(2-trimethysilylethoxymethyl) -
3H-imidazo-[4,5-b]-pyridine (1.3 g, 4 mmol) and bis(triphenylphosphine)-
palladium (II) chloride in DMF (12 mL) was added tributylvinyl tin (2.14
g, fi.7 mmol). The reaction vessel was evacuated-purged (NZ) several
times followed by heating to 95 °C for 15 h. After cooling, the crude
reaction mixture was filtered through a pad of celite~ and eluted with
ethyl ether. The ethereal mixture was washed several times with
saturated KF, brine, dried (NazS04), filtered and concentrated in vacuo.
The crude residue was purified by flash chromatography on silica gel
using a gradient elution of ethyl acetate/hexanes ( 10, 20, 30 to 40%)
which provided 1.06 g of the title compound (97% yield).
Step FFF: 6-(2-Bromo-1-hydroxyethyl)-3-(2-trimethysilyl-
ethox et ~- 3H-imidazof4,5-bl-Ryridine
To a soution of 6-ethenyl-3-(2-trimethysilylethoxymethyl) -
3H-imidazo-[4,5-b]-pyridine (1.06 g, 3.8 mmol) in DMSO-H20 (18.0 mL/2.0
mL) was added N bromosuccinimide (1.37 g, 7.7 mmol) slowly over 5
min. The reaction was maintained at ambient temperature for 30 min
at which time the reaction mixture was partitioned between ethyl
acetate-H20. After separation of the layers, the aqueous layer was
extracted three times with ethyl acetate. The combined extracts were
washed with brine, dried (Na2S04), filtered and concentrated in vacuo.
The crude residue was used without further purification.
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Step GGG: 6-Oxiranyl-3-(2-trimethylsilylethoxymethyl)-3H-imidazo-
[4_,5-bl p~dine
The crude 6-(2-bromo-1-hydroxyethyl)-3-(2-trimethysilyl-
ethoxymethyl) -3H imidazo[4,5-b]-pyridine (1.42 g, 3.8 mmol) was
dissolved in (5:1) THF-t-butanol (20 mL) to which potassium t-butoxide
(0.85 g, 7.6 mmol) was added in several portions over 5 min. After 90
min at ambient temperature, , the reaction mixture was partitioned
between ethyl acetate-H20. After separation of the layers, the aqueous
layer was extracted three times with ethyl acetate. The combined
extracts were washed with brine, dried (Na2S04), filtered and
concentrated in vacuo. The crude residue (918 mg) was used without
purification.
Step HHH: 2-[3-(2-Trimethylsilylethoxymethyl)-3H-imidazo-
f4,5-blR~din-6-yll-ethanol
6-Oxiranyl-3-(2-trimethylsilylethoxymethyl)-3H-imidazo-
[4,5-b]pyridine (918 mg, 3.15 mmol) was combined with 10% Pd/C (400
mg) and ammonium formate (993 mg, 15.75 mmol) and the mixture was
suspended in methanol (25 mL). The reaction mixture was heated to
70°C for 2.5 h. After cooling to ambient temperature, the mixture was
filtered through celite~, eluted with methanol, concentrated in vacuo.
The crude residue was purified by flash chromatography on silica gel
using 75% ethyl acetate/hexanes then 95:5 CH2C12/MeOH as the eluents,
which provided 480 mg of the title compound (43% yield for 3 steps).
Following procedures similar to those described above, the
following compounds are prepared:
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CA 02325995 2000-09-26
WO 99/51231 PCT/US99/06713
-R~
Ex. # -(A)-R1
1A ~ N
~N~
N
Me
1B
N
N
N H
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