Note: Descriptions are shown in the official language in which they were submitted.
28-07-1999 PCT~CA99/00311 P~~ ~ ~~ y ~ lISA-DESC2S~.'._;'
;JU~.I~ 1999 ~ 0 9 ~ 0 ? y~
CUBANS ANALOGS WTTH ACTIVITY AT THE
METABOTROPIC GLUTAMATE RECEPTORS
FIELD OF THE INVENTION
This invention pertains to therapeutically active cubane derivatives, a method
for preparing the
same, pharmaceutical compositions comprising the compounds and a method of
treating diseases
of the Central Nervous System (CNS) therewith.
BACKGROUND OF THE INVENTION
The acidic amino acid L-Glutamate is recognized as the major excitatory
neurotransmitter in the
CNS. The receptors that respond to L-Glutamate are called excitatory amino
acid receptors. The
excitatory amino acid receptors are thus of great physiological importance,
playing a role in a
variety of physiological processes, such as long term potentiation (learning
and memory), the
development of synaptic plasticity, motor control, respiratory and
cardiovascular regulation, and
sensory perception.
Excitatory amino acid receptors are classified into two general types and both
are activated by
L-Glutamic acid and its analogs. Receptors activated by L-Glutamic acid that
are directly coupled
to the opening of cation channels in the cell membrane of the neurons are
termed "ionotropic."
This type of receptor has been subdivided into at least three subtypes, which
are defined by the
depolarizing actions of the selective agonists N-Methyl-D-aspartate (I~1MDA),
oc-Amino-3-
hydroxy-5-methylisoxazole-4-propionic acid (AMPA), and Kainic acid (KA).
_ The second general type of receptor is the G-protein or second messenger-
linked "metabotropic"
excitatory amino acid receptor This second type is coupled to multiple second
messenger
systems that lead to enhanced phosphoinositide hydrolysis, activation of
phospholipase D,
increases or decreases in cAMP formation, and changes in ion channel function
(Schoepp and
Conn, Trends in
Pharmacological Science, 14:13, 1993). Both types of receptors appear not only
to mediate
normal synaptic transmission along excitatory pathways but also to participate
in the modification
of synaptic connections during development and throughout life.
So far eight different clones of the G-proxein-coupled metabotropic. glutamate
receptors
. (mGluRs) have been identified (Knopfel et al., 1995, J. Meci' Chem., 38,~-
1417-1426). These
receptors function to modulate the presynaptic release of L-Glutamate, and the
postsynaptic
1
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sensitivity of the neuronal cell to L-Glutamate excitation. Based on
pharmacology, sequence
homology and the signal transduction pathway that they activate, the mGluRs
have been
subclassified into three groups. The mGluR1 and mGluRS receptors form group I.
They are
coupled to hydrolysis of phosphatidylinositol (PI) and are selectively
activated by (R,S~-3,5-
dihydroxyphenylglycine (Brabet et al., Neuropharmacology, 34, 895-903, 1995).
Group II
comprises mGluR2 and mGluR; receptors. They are negatively coupled to
adenylate cyclase and
are selectively activated by (2S,1'R,2'R,3'R)-2-(2,3-
dicarboxycyclopropyl)glycine (DCG-IV;
Hayashi et al., Nature, 366, 687-690, 1993). Finally, the mGluR~, mGluRs,
mGluR, and mGluR$
receptors belong to group III. They are also negatively coupled to adenylate
cyclase and are
selectively activated by (L)-2-amino-4-phosphonobutyric acid (L-AP4; Knopfel
et al., 1995, J.
Med Chem., 38, 1417-1426).
Agonists and antagonists of these receptors are believed useful for the
treatment of acute and
chronic neurodegenerative conditions, and as antipsychotic, anticonvulsant,
analgesic, anxiolytic,
antidepressant, and anti-emetic agents. Antagonists and agonists of neural
receptors are classified
as selective for a particular receptor or receptor subtype, or as non-
selective. Antagonists may
also be classified as competitive or non-competitive. While competitive and
non-competitive
antagonists act on the receptors in a different manner to produce similar
results, selectivity is
based upon the observations that some antagonists exhibit high levels of
activity at a single
receptor type, and little or no activity at other receptors. In the case of
receptor-specific diseases
and conditions, the selective agonists and antagonists are of the most value.
Compounds such as L-Glutamic acid, Quisqualic acid and Ibotenic acid are known
to act as non-
selective agonists on the mGluRs, while selective ionotropic glutamate
receptor agonists such
as NMDA, AMPA and Kainic acid have little effect on these receptors. Recently
a few
compounds without activity at the ionotropic glutamate receptors but with
activity at the
metabotropic receptors have been identified. These include traps-ACPD (traps
(1S,3R-1-
aminocyclopentane-1,3-dicarboxylic acid), the partial agonist L-AP3 (L-2-amino-
3-
phosphonopropionic acid, Palmer, E., Monaghan, D. T. and Cotman, C. W. Eur.
.I. Pharmacol..
166, 585-587, 1989; Desai, M. A and Conn, P. J. Neuroscience Lett. 109, 157-
162, 1990,
Schoepp, D. D. et al., J. Neurochemistry. 56, 1789-1796, 1991; Schoepp D. D.
and Johnson B.
ii ,%. IVeurochejoi.sn~: ~3, 186-1613, 1989), 1.-.~P4 (L-2-anuno-4-
phospilonobutyric acid) which
is an agonist at the mGluR4 receptor (Thomsen C. et al., Errr. .l. Phar-
nracol. 227, 361-362,
199?l and some of the isomers of CCG (?-(carbo~~~cvclopropyf jliycin°sl
especially L-CCG-I and
r_-CCG-Il (Hayashi, Y. et al., Br. .l. Pharmacol. 107, 539-543, 1992)
..s~_
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Very few selective antagonists at the mGluRs have been reported. However some
phenylglycine
derivatives, S-4CPG (S-4-carboxyphenylglycine), S-4C3HPG (S-4-carboxy -3-
hydroxyphenylglycine) and S-MCPG (S-a-methyl-4-carboxyphenylglycine) have been
reported
to antagonize bans-ACPD- stimulated phosphoinositide hydrolysis and thus
possibly act as
antagonists at mGluR~ and mGluRs subtypes (Thomsen, C. and Suzdak, P, Eur. J.
Pharmacol. '
245, 299, 1993).
Research directed towards mGluRs is beginning to show that mGluRs may be
implicated in a
number of normal as well as pathological mechanisms in the brain and spinal
cord. For example,
activation of these receptors on neurons can: influence levels of alertness,
attention and
cognition; protect nerve cells from excitotoxic damage resulting from
ischemia, hypoglycemia
and anoxia; modulate the level of neuronal excitation; influence central
mechanisms involved in
controlling movement; reduce sensitivity to pain; reduce levels of anxiety.
The use of compounds active at the mGluRs for the treatment of epilepsy is
corroborated by
investigations of the influence of traps-ACPD on the formation of convulsions
(Sacaan and
Schoepp, Neurascierrce Lett. 139, 77, 1992) and that phosphoinositide
hydrolysis mediated via
mGluR is increased after kindling experiments in rats (Akiyama et al. Brain
Res. 569, 71, 1992).
Traps-ACPD has been shown to increase release of dopamine in the rat brain,
which indicates
that compounds acting on the mGluRs might be usable for the treatment of
Parkinson's disease
and Huntington's Chorea (Sacaan et al , J. Neurochemistfy 59, 245, 1992).
Traps-ACPD has also been shown to be a neuroprotective agent in a medial
cerebral artery
occlusion {MCAO) model in mice (Chiamulera et al. Ern-. J. Plurrmacvl. 215,
353, 1992), and
it has been shown to inhibit NMDA-induced neurotoxicity in nerve cell cultures
(Koh et al.,
Proc. Natl Acad. Sci. LISA 88, 943 l, 199I). The mGluR-active compounds are
also implicated
in the treatment of pain. This is proved by the fact that antagonists at the
metabotropic glutamate
receptors antagonize sensory synaptic response to noxious stimuli of thalamic
neurons (Eaton,
S. A. et al , Ear. J. Nenro.s~cience, 5, 186, 1993).
The use of compounds active at the mGluRs for treatment of neurological
diseases such as senile
dem°nna gave aiso peen indicated dy tile nndings of Zi~en~ and
Galiaji~er (IVeIII'O77 9, 103, 1992)
and Bashir et al. (Nature 363, 347, 1993) who demonstrated that activation of
rnGluRs is
. necessart- for the induction of lop;-term potentiation (LTP) in nen~e cells
(septal nucleus,
hippocampusj and the finding that long-term depression is induced after
activation of
metabotropic glutamate receptors in cerebellar granule cells (Linden et al.
Nelll'UTl 7, 81, 1991 ).
3
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Thus compounds that demonstrate either activating or inhibiting activity at
mGIuRs have
therapeutic potential for the treatment of neurological disorders. These
compounds have
application as new drugs to treat both acute and chronic neurological
disorders, such as stroke
and head injuries; epilepsy; movement disorders associated with Parkinson's
disease and
Huntington's chorea; pain; anxiety; AIDS dementia; and Alzheimer's disease.
Since the mGluRs
can influence levels of alertness, attention and cognition; protect nerve
cells from excitotoxic
damage resulting from ischemia, hypoglycemia and anoxia; modulate the level of
neuronal
excitation; influence central mechanisms involved in controlling movement;
reduce sensitivity to
pain; and reduce levels of anxiety, these compounds can also be used to
influence these situations
and also find use in learning and memory deficiencies such as senile dementia.
mGluRs may also
be involved in addictive behavior, alcoholism, drug addiction, sensitization
and drug withdrawal
(Science, 280:2045, 1998), so compounds acting at mGluRs might also be used to
treat these
disorders.
The current pharmaceutical options for treating neurological disorders tend to
be very general
and non-specific in their actions in that, although they may reduce the
clinical symptoms
associated with a specific neurological disorder, they may also negatively
impact normal function
of the central nervous system of patients. Thus new cellular targets and drugs
that are more
specific in their actions require to be identified and developed and thus a
need remains for
chemical compounds that demonstrate specific binding characteristics towards
mGluRs.
4
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P~'~/tr~ 9~/UUSi a
SUMMARY OF THE INVENTION o 9 JULY - 1999 ~0 9 y 0 7 ~ ~9
It is an object of this invention to provide novel compounds that demonstrate
activity at the
various metabotropic glutamate receptors (mGluRs). In particular, a compound
of Formula I
and stereoisomers thereof
R1
(I)
R2
R4
R3
wherein:
Rl can be an acidic group selected from the group consisting of carboxyl,
phosphono,
phosphino, sulfono, sulfino, borono, tetrazol, isoxazol, -CHz-carboxyl, -CHZ-
phosphono, -CH2-
phosphino, -CHz-sulfono, -CHZ-sulfino, -CHz-borono, -CHZ-tetrazol, -CH2-
isoxazol and higher
homologues thereof
R2 can be a basic group selected from the group consisting-of 1° amino,
2° amino, 3° amino,
quaternary ammonium salts, aliphatic 1° amino, aliphatic 2°
amino, aliphatic 3° amino, aliphatic
quaternary ammonium salts, aromatic 1° amino, aromatic 2° amino,
aromatic 3° amino, aromatic
quaternary ammonium salts, imidazol, guanidino, boronoamino, allyl, urea,
thiourea,
R3 can be H, aliphatic, aromatic or heterocyclic,
R4 can be an acidic group selected from the group consisting of carboxyl,'
phosphono,
phosphino, sulfono, sulfino, borono, tetrazoi, isoxazol;
and pharmaceutically acceptable salts thereof.
DETAILED DESCRIPTION OF TI3E ~1VENTTON
The terms and abbreviations used in the instant examples have their normal
meanings unless
otherwise desi,nated For e:~ample "°C" refers to de;rees Celsius, "N"
refers to normal or
normality; "mmol" refers to millimole or millimoles; "g" refers to gram or
grams; "mL" means
milliliter or milliliters; "M" refers to molar or molarity, "MS" refers to
mass spectrometry, "1R"
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refers to infrared spectroscopy; and "IVMR" refers to nuclear magnetic
resonance spectroscopy.
As would be understood by the skilled artisan throughout the synthesis of the
compounds of
Formula I, it may be necessary to employ an amino-protecting group or a
carboxy-protecting
group in order to reversibly preserve a reactively susceptible amino or
carboxy functionality
while reacting other functional groups on the compound.
Examples of such amino-protecting groups include fonmyl, trityl, phthalimido,
trichloroacetyl,
chloroacetyl, bromoacetyl, iodoacetyl, and urethane-type blocking groups such
as
benzyioxycarbonyl, 4-phenylbenzyloxycarbonyl, 2-methylbenzyloxycarbonyl,
4-methoxybenzyloxycarbonyI, 4- fluorobenzyloxycarbonyl, 4-
chlorobenzyloxycarbonyl,
3-chlorobenzyloxycarbonyl, 2-chlorobenzyloxycarbonyl, 2,4-
dichlorobenzyloxycarbonyl,
4-bromobenzyloxycarbonyl, 3-bromobenzyloxycarbonyl, 4-nitrobenzyloxycarbonyl,
4-cyanobenzyloxycarbonyl, t-butoxycarbonyl, 2-(4-xenyl)-isopropoxycarbonyl,
1, I-diphenyleth-1-yloxycarbonyl, I, I-diphenylprop-1-yloxycarbonyl,
2-phenylprop-2-yloxycarbonyl, 2-(p-toluyl)-prop-2-yloxycarbonyl,
cyclopentanyloxy-carbonyl,
I-methyicyclopentanyloxycarbonyl, cyclohexanyloxycarbonyl, 1-
methylcyclohexanyloxycarbonyl,
2-methylcyclohexanyioxycarbonyl, 2-(4-toluylsulfono)-ethoxycarbonyl,
2-(methylsulfono)ethoxycarbonyl, 2-(triphenylphosphino)-ethoxycarbonyl,
fluorenylmethoxycarbonyl ("FMOC"), 2-(trimethylsilyl)ethoxycarbonyl,
allyloxycarbonyl,
1-(trimethylsilylmethyl)prop-1-enyloxycarbonyl, 5-benzisoxalylmethoxycarbonyl,
4-acetoxybenzyloxycarbonyl, 2,2,2-trichloroethoxycarbonyl, 2-ethynyl-Z-
propoxycarbonyl,
cyclopropylmethoxycarbonyl, 4-(decycloxy)benzyloxycarbonyl,
isobornyloxycarbonyl,
1-piperidyloxycarbonlyl and the like; benzoylmethylsulfono group, 2-
nitrophenylsulfenyl,
diphenylphosphine oxide and like amino-protecting groups. The species of amino-
protecting
group employed is not critical so long as the derivatized amino group is
stable to the condition
of subsequent reactions) on other positions of the intermediate molecule and
can be selectively
removed at the appropriate point without disrupting the remainder of the
molecule including any
other amino-protecting group(s). Preferred amino-protecting groups are t-
butoaycarbonyl
(t-Boc), allyloxycarbonyl and benzyloxycarbonyl (CbZ) Further examples of
these groups are
found in E. Haslam in Protective Groups in Organic Syf~thesi.s; McOmie, J. G.
W., Ed. 1973,
at Chapter 2; and Greene, T.W. and Wuts, P. G. M., Protective Grasps in
Organic Synthesis,
Second eaition; Whey-interscience: 1991; Chapter 7.
Examples of such carboxyl-protecting groups include methyl, p-nitrobenzyl, p-
methylbenzyl,
p-methoavbenzvl, 3,4-dimethoxybenzyl_ ~,4-dimethoxybenzvl, 2.4,6-
trimethoxybenzyl,
2,4,G-trimethylbenzyl, pentamethylbenzyl, 3,4-methylenedioxybenzyl,
benzhydryl,
4,4'-dimethoxybenzhydryl, 2,2',4,4'-tetramethoxybenzhydryl, ~-butyl, ~-amyl,
trityl,
6
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Pr~nted:l2~ 02328984 2000-10-16 . . ._-
28-Q7-1999 PCT/CA99/003'11 - ~ ~ ISA-DESC26~~
0 ~ JULY 199 C 0 9 - 0 7 - 99
. _
4-methoxytrityl, 4,4'-dimethoxytrityl, 4,4',4"-trimethoxytrityl, 2-phenyiprop-
2-yl, trimethylsilyl,
t-butyldimethylsilyl, phenacyl, 2,2,2-trichloroethyl, (3-(di(n-
butyl)methylsilyl)ethyl,
p-toluenesulfonoethyl, 4-nitrobenrylsulfonoethyl, allyl, cinnamyl,
I-(trimethylsilylmethyl)prop-1-en-3-yl and like moieties. Preferred carboxyl-
protecting groups are
allyl, benryl and t-butyl. Further examples of these groups are found in E.
Hasiam, supra, at Chapter
5; and T. W. Greene and P. G. M. Wuts, supra, at Chapter S.
The present invention provides a compound of the formula:
RI
(I)
R2
R4
R3
wherein:
R1 can be an acidic group selected from the group consisting of carboxyl,
phosphono, phosphino,
sulfono, sulfino, borono, tetrazol, isoxazol, -CH2-carboxyl, -CHZ-phosphono, -
CHz-phosphino, -
CHZ-sulfono, -CH2-sulfino, -CHZ-borono, -CHZ-tetrazol, -CHZ-isoxazol and
higher analogues
thereof
R2 can be a basic group selected from the group consisting of I° amino,
2° amino, 3° amino,
quaternary ammonium salts, aliphatic 1° amino, aliphatic 2°
amino, aliphatic 3° amino, aliphatic
quaternary ammonium salts, aromatic I° amino, aromatic 2° amino,
aromatic 3° amino, aromatic
quaternary ammonium salts, imidazol, guanidino, boronoamino, allyl, urea,
thiourea ;
R3 can be H, aliphatic, aromatic or heterocyclic;
R4 can be an acidic group selected from the group consisting of carboxyl,
phosphono, phosphino,
sulfono, sulfino, borono, tetrazol, isoxazol;
any pl;a-ma~~a;i:.aliv a;,~°p~abie ~ai:~ :~°r~o
7
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20-07-2000 ~ ~~ ~ . PCT/CA99/00311 DESC
In particular compounds whcr~cin the compound of Formula I i.9 sclecacd from
the group
consisting of:
R
(I)
wherein: '
>K1 is COOl-t
K2 is Nf~li
R3 can bc: I! or methyl c>r xankhyl c>r thicyxanthyl or-C:IIZ-xanlhyl or-GHZ-
thioxanthyt and
R4 is COdH
While all of lhr com~unds.~f I~'ormula I area bc;lier~e~i tn de;mnnstraie
at.tivity et the rnctabt~trc~pic
glutam~ctc receptors (rnCIuRs), certain groups of Formula I compounds arc more
preferred for
such use.
As noted above, this invcntirrn includes the pharmaceutically acceptable
.salts of the compounds
defined by Formula 1. A e4mpound of thin inventicm cari posses a sufficiently
acidic, a
sufficie~nil3~ x~asic, car both functional groups, and accordingly rt;act with
any of a number of
organic and inorganic baso.s, and inorganic and or~aryic acids, io form a
pharmaceutically
acc;epta.ble salt. c
The term "pharmaceutically acreptablc salt" as uscxi herein, rcfrrs to salts
of the compounds of
the: above fc~rmul:~ which are sululantially non-toxic to living organisms.
Typical
pharrnacxutic:aJiy aax;ptablc saris include; those;.salts prepared by
rcaclionof the cor~our~ds of
the pnsinl invention with a pharmaceutically acceptable mineral or organic
acid nr cure c>rganic
or inorganic base. Such salts toe known as acid addition ancJ base addition
salts.
Arias a>nmx>nfy crnpioycxi ic> iorrrt acid aaditicm salts ~ itnNgdnic arias
Surh as hydr;~"hloric; acid, . .
hydrotm~mic acid hydriodic acid, sulfuric acid, pht~sphoric acid, anct the
like, and organic acici~ such as
p-u~tucr~ulfonic a;.-id, t~"than~'ulfnnic avid, oxalic a:;irl, ~-
bromoplx:nyLsulfonic a:..id, c~uhonic
8
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28-07-1999 PCT1Ci499/00311 P~~ ~ ~~ ~ ~ ' ' ISA-DESC26
~ 9 . Jl9LY ~~99 ~ ~ 9 ° ~ 7 ° ~~
acid, succinic acid, citric acid, benzoic acid, acetic acid, and the like.
Examples of such
pharmaceutically acceptable salts are the sulfate, pyrosulfate, bisulfate,
sulfite, bisulfite, phosphate,
monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate,
bromide, iodide,
acetate, propionate, decanoate, caprylate, acryiate, fonnate, hydrochloride,
dihydrochloride,
isobutyrate, caproate, heptanoate, propiolate, oxalate, malonate, succinate,
suberate, sebacate,
fumarate, maleate, butyne-1,4-dioate, hexyne-1,6-dioate, benzoate,
chlorobenzoate, methylbenzoate,
hydroxybenzoate, methoxybenzoate, phthalate, xylenesulfonate, phenylacetate,
phenylpropionate,
phenyibutyrate, citrate, lactate, gamma-hydroxybutyrate, glycolate, tartrate,
methanesulfonate,
propanesulfonate, naphthalene-1-sulfonate, napththalene-2-sulfonate, mandelate
and the like.
Preferred pharmaceutically acceptable acid addition salts are those formed
with mineral acids such
as hydrochloric acid and hydrobromic acid, and those formed with organic acids
such as malefic acid
and methanesulfonic acid
Salts of amine groups may also comprise quarternary ammonium salts in which
the amino nitrogen
carries a suitable organic group such as an alkyl, alkenyl, alkynyl, or,
aralkyl moiety.
Base addition salts include those derived from inorganic bases, such as
ammonium or alkali or
alkaline earth metal hydroxides, carbonates, bicarbonates, and the like. Such
bases useful in
preparing the salts ofthis invention thus include sodium hydroxide, potassium
hydroxide, ammonium
hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate,
potassium bicarbonate,
calcium hydroxide, calcium carbonate, and the like. The potassium and sodium
salt forms are
particularly preferred
It should be recognized that the particular counterion forming a part of any
salt of this invention is
usually not of a critical nature, so long as the salt as a whole is
pharmacologically acceptable and as
long as the counterion does not contribute undesired qualities to the salt as
a whole. This invention
further encompasses the pharmaceutically acceptable solvates of the compounds
of Formula I. Many
of the Formula I compounds can combine with solvents such as water, methanol,
ethanol and
acetonitrile to form pharmaceutically acceptable solvates such as the
corresponding hydrate,
methanolate, ethanolate and acetonitrilate.
The compounds of the present invention have multiple asymmetric {chiral)
centers As a
consequence of these chiral centers, the compounds of the present invention
occur as racemates.
mixtures of enantiomers and as individual enantiomers, as well as
diastereomers and mixtures of
9
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diastereomers. All asymmetric forms, individual isomers and combinations
thereof, are within the
scope of the present invention.
The prefixes "R" and "S" are used herein as commonly used in organic chemistry
to denote the
absolute configuration of a chiral center, according to the Cahn-Ingold-Prelog
system. The
stereochemical descriptor R {rectus) refers to that configuration of a chiral
center with a clockwise
relationship of groups tracing the path from highest to second-lowest
priorities when viewed from
the side opposite to that of the lowest priority group. The stereochemical
descriptor S (sinister)
refers to that configuration of a chiral center with a counterclockwise
relationship of groups tracing
the path from highest to second-lowest priority when viewed from the side
opposite to the lowest
priority group. The priority of groups is decided using sequence rules as
described by Cahn et al.,
Arrgew. t:henr., 78, 413-447, 1966 and Prelog, V. and Helmchen, G , Afr~ew.
Chenr. Irrr. Ed End.,
21, 567-583, 1982).
In addition to the R,S system used to designate the absolute configuration of
a chiral center, the
older D-L system is also used in this document to denote relative
configuration, especially with
reference to amino acids and amino acid derivatives. In this system a Fischer
projection of the
compound is oriented so that carbon-1 of the parent chain is at the top. The
prefix "D" is useø to
represent the relative configuration of the isomer in which the functional
(determining) group is on
the right side of the carbon atom at the chiral center and "L", that of the
isomer in which it is on the
left.
As would be expected, the stereochemistry of the Formula I compounds is
critical to their potency
as agonists or antagonists. The relative stereochemistry is established early
during synthesis, which
avoids subsequent stereoisomer separation problems later in the process.
Further manipulation of
the molecules then employs stereospecific procedures so as to maintain the
preferred chirality. The
preferred methods of this invention are the methods employing those preferred
compounds.
Non-toxic metabolically-labile esters and amides of compounds of Formula I are
ester or amide
derivatives of compounds of Formula I that are hvdrolvzed in vivo to afford
said compounds of
Formula I and a pharmaceutically acceptable alcohol or amine. Examples of
metabolically-labile
esters include esters formed with (1-6C) alkanols in which the alkanol moiety
may be optionally
substituted by a~( 1-SC) alko~ry ;roup, for exampi:; methanol, ethanol.
propanol and methoxvethanol
Examples of metabolically-labile amides include amides formed with amines such
as methvlamine
(i5 ;. ~ 5.~~., ':-. a~:: ~ r_~~,a ~. r~ r~~ ~Z ;.-.y : ; . .: , a
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20-07-2000 ' ~ PCT/CA99100311 'DESC
4ccordinb to another aspoet, the prr,9cnt inventicm provides a Prcx;eaa for
the preparation of a
compound of F~~rmu(a I, cn a pharataceutically acceptable mctabca(icaliy-
labile ester ur amide
therc.~,of, or a pharmaceutically aceeptabla salt thercx~P, which eomprisos:
(a) hydmlyiing a ccwmpound of fcnmula. (TIa):
R'1
(lla)
NC
k3
whcrcu~: It'1 i.~ an acidic gmnp seiec;tc;d from the gctmp wnsisling of
carboxyl, phosplumu,
pllL~Spt77110, suifonc~, sulfina, bomno, tetrd~Ul, i,9t~xazol, -t':,'H~-
carboxyl, -CHa-phosphono, -CIiL-
phosphino. -CHZ sulfnnu, -CHZ-suJfino, -CHZ-borr~nu, -CH2-tetr~ol, CHZ-
i'oxazol and higher
analogues nhereof, or a prcatc;cted form thereof, R:i can be H, aliphatic.
amrnatic or hcterocyclic
and R5 rprescnU a hydrubTcn atom or an acyl group. 1'roferred values for RS
are hydrogen and
(,2-6C) alhanoyl groups, such as acetyl; Ur
(E~) dcprot.txting and hydrolysing a u~mpcsuntl c.~f forrnulti (TI b)
R' 1
CN fllb?
x:~
H
H
Ph
DH
a'hercin: >~ I :~n<i R~ are as deCii~;a acs: we; cr
Printed:l2-~ 02328984 2()()()-1()-16
20-D7-2000 4~ ~ PCT1CA99/00311 'DESC
(c) hydrolyzing a compound ~f formula:
till)
-R6
wherein: R'1 and R3 has the meaning defined atxwe, Rb arid R7 each
uicielx,~ndenuy rGpresE;nt a
hydrogen atom; a (2-6L) alkanoyi group, a (1-~C) alkyl group, a (3-4C) alkenyl
grnup or d
phenyl (1-4C) alkyl groin in which the phenyl is unsubstitutc~xi or
substituted by haloge», (1-4C)
alkyl ar (1-4C) alkoxy, or a salt thereat; nr
V
i
1~$
Printed. 2-~ 02328984 2000-10-16
.~. r-, v v v
20-07-20Q0 ' ;/ PC~'/CA99/00311 DESC
(d) dcprotecting a cnmpc~und of formula:
R'1
(jV)
R
~wherCin; R'1 dnd R3 has the meanlnb defined above, RS r~pr~cnta a hydrogen
atom yr tz carboxyl
protecting group, or a salt thereof, annd R9 rcpre~enls a hydrogen atom ar a
nitrogen pmlecaing
broup;
whcreafter, if necessary andwr desircxl:
(i) resolving the compound of Formula I;
(ii) c,.vnvcrting lhc cnmlx.~und of formula 1 into a non toxic rnctabolically-
labile aster yr amide
thereof;
and/or;
(iii) converting the compound of FcmnuIa I or a nun-tnxic metabolically-
lalaile aster or 3midc thereat
into a pharmaceutically aceel~table Bali Thereof.
0
The prottcvion of ~arbnxylic acid and amino gn~ups is generally described in
MeOmie, Prvtecling
C~rrouhs in Urgaraic Chemistry, Plenum Prc;ss, NY, 197:3, and Greenc and Wets,
Prvtc;cting Gmulrs
in Urganic Synthr;sis, 2nd. Td., John Wiley & Son.,, NY, 1991. Examplss of
carboxyl protecting
groups include alkyl groups such as methyl, ethyl, r-butyl and i-amyl: aralkyi
groups such as bcn2yl,
4-nitrabencyl, d-molhc~xybenryl, 3,4-dimc;thoxybcnzyl, 2,4-dimc;thoxybunzyl,
x,4,6-trimcthoxybcrztyn, Z,4,6-irimethylbc;ruyl, benchydryl and trityl; silyl
groups such as
trimcehylSilyl and t-butyldimcthylsilyl; and allyl groups serch as allyl and
'1-(trimethylsilylmclhyl)prop-1-en-3-yl. ,
Examples of arninc-protecting groups in~;tude aryl groups, such as groups of
formula R9 CO in
~svhich RSi re;pra~nW (1-6C) alkyl, (3-tOCj cycloalkyl, phenyl(I-bC) ailcyi,
phenyl(1-bC) alKOxy, or
a (3-lOC) cyclaalkaxy, wherein a phenyl group may optionally tx: substituted
by or~~ or lwu
' I2
CA 02328984 2000-10-16
Ptinted:l 2-10-2000
2D-07-2000 ~f ~ PCT/CAg9/00311 DESC
Pub9tituents indc;pendentty sekxtc;d from amiro~. hydroxy. vitro, halogeno, (1-
6C) alkyl, (I-6C)
alkc~xy, carboxyl, (1-6C) alkoxyc;arbonyl, carbamoyt, (I-6C) alkannylamino. (i-
6C)
alkylsuiph~rtylamino, plienylsulphonylarttino. toluenc;,s-utphanylarnino, and
(1-6C) fluoraalkyl.
The con-vpourtds of Formula II are convonicntly hydrcflyred in the prc;sence
of an acid, such a.~
hydrochloric acid or sulfuric acid, or a base, .ouch as an alkali metal
hydroxide, for example sodium
hydroxide. The hydrolysis i.y c~nv~niently porformcd in an aduenus solvent
such as water and at a
temperature; in the rangt; of 5U to 200 °C.
1'he compounds of Formula 1II arc vonveniently hydrt~lyic;d in the prc;sencc
of a base, for example
an alkali tneWl hydroxide such as l.ithiurn, sodium ur pota.~situ~n hydroxide,
or an alkaline easth mct,al
hydroxide such as barium hydroxide, Suiictblc reaction rncdia include water.
The tcmpc;rature is
amvedicntty in the range of from 50 to I50 °C.
The cornpc~unds of Formula 1V rrtay be deprotectcx3 by a conventional method,
Thus, an alkyl
carboxyl protecting gmup may be rernovcxt by hydrolysis. 'fhc hydrolysis may
conveniently be
performc;d by heating the compound of 7~ormulx ) V in the presence ~~f either
a base, for example an
alkali ~nctal hydroxide ,such as lithium, snclium or puta.ssium hydroxide, or
an alkaline metal
hydroxide, leech as barium hydroxide, ar an acid such as hydrochloric acid,
The hydrolysis is
conveniently perfonned at a temFx;rature in the range from 10 to 300
°C. An aralkyl carboxyl
protecting group may ct~nvenicntly be remcwed by hydrogenolysis. The
hydrobenolysis may
conveniently be cffectod by reacting tt~ compound of P'urmuta IV with hydrogen
in the premxe
co a Gtvup VIII rnotal catalyse, for examplo a palladium catalyse sucty as
palladium on charcoal.
Suitable sc~ivents fur the reaction include alcohuLs such as ethanol. 'fhe
reaction is convcnicnily
performed at a temperature in the range From 4 tot Ua °C. An aryl,
amine protecting group is also
ccmvc:nienl(y removexJ by bydraolysis, for exdml~ic a.~ dcscribod for the;
removal of an alkyl carboxyl
pmtectcng gmup.
The compounds of Formula f ( rnay he prt;pared by re:ucting t~ compound of
furrnultt (V):
fVi
li
PriTited:l2-X2328984 2ooo-io-is
i
20-07-2000 ~ PCTlCA99/003'i 1 DESC
with an alkali mrtal c.~yanide, such as Iil,hium, sodium or ptitussiurn
cya~zidc, acxi an amrnanium
Jlaiide, ouch as nannocaum chloride, convecucnrly in the prcscnce esL
ultres~und. Thus, the
ammonium halide is mixed wish chrcxna.tcsgraphy grade aluznina in the
presence; of a suitable dituent
Such as ac;otonitrile. The mixture iv then irradiateel with uttras~ound,
whereafic,~r the compound of
Formula t1 is added, and the rni~:cure is again irradiatc;d. 1'he alkali mesa(
cyanide is ihcan added,
t«llowed by farther irrediati~~rt with ulCrasound.
lndividuat isc~mcrs of compUCmds of Formula I muy be mado by reacting a
compound of the hurmccla
V with the St~I~UiSa1118rS Uf tllC ClllTal agent {.S')- anti (R)-
phc;nylgiycinnt and a reac~ive cyanide such
a~ trimeUiylsityl cyanide.
The compounds of Formula 111 may be prepared by rcactu~g a cc~mpc~und of
Formula V with an
alkali metal cyanide, such ac lilhimn, sodium or potassium cyanide;, and
ammoni;nn carbnn~tie ur
anmc.~nium c:arhamate. Convenient solvents include water, dilute ammonium
hydroxide, alcnlu~ls
such as m~tharn~l, a.quasus methanol and arlut~us ethanol. ~Convenic,,nlly the
rcaCtion is perfcarrned
r
at a temLxrature in the range of from 10 to 1$d ° C'.. If dr,~sirod,
the contpaunds of Formula I1I may
then be atkylatc,~d, l~or c;xample using an appropriate compnmd of fnrrriula
RG Cl andlor k7 C1,
The cconpounds of C'orrnula V ion be preparut by reacting acc~rnpc~und of
formula:
'1
tvn
CCz~
with a chlorinating agent such as th:onyi chlvridc or phc~sphoncms {t~
Chloride. followed by r~c:actiun
with urgano copper or vrgancs rnetaI car (3rignard roagent iferived from R:~ X
or by raaetion wifih ethyl
hydrogc;n malUnatr in the: presence of orgdnolithium, wherein R3 has the
rneuning definr:d aix~r~e
1~
ar,a .. i~ ttalvgvr.
!4
CA 02328984 2000-10-16
Printed:l 2-10-2000 g
/ ,
20-07-2000 ~ '~ 'PCT/CA99100311 DESK
The compouzta5 of F'c~rmuta V can ats~ trc3 prcparrd by oxidixinbT a compound
of formula
R'i
(~)
CI3,GH
under Swcm ccms3ition~. '
The er~mlx~nnds of Fornwla VI ran be prepanxl from compounds of formula:
R' 1
tV I~1)
GOzR
by reduction.
Whc~ R'I is C~OZMe, this ccampoundcan be ix~ught commercially. Wtx:n R'1 as
ar:Uthc~r5ubst~tuc~nt,
the ccampuund of Formula VIII can be made usin6 standard proceciurc;s.
Many of the intermcx~tiates dc:,scribtxl heni.n, for c~mple: the cr~mpvunds of
Formula II,11i and IV
arc lyclicved to be: newel, and arc provided as further aspects of lhc
invc;nlion.
'fhe Formula 1 compounds of the presfant invention ~e agonist, Ar antagonists
at crrtau~
metabatropic excitatory amino acid rec:c~tor5 (mGluK,S). Tl~rcfore, another
aspect ut the present
invention is a method of aifccting mGlults in mt~mrnal~. which comprises
adrninistcrin~ to s
mamtrtal rc;quiring mocfulatc~ excitptory amino acid neur~c~transmission a
pharmaculcyically-eflcetive amount c~f a ec>m-puund c~f Forrnvla 1. The torni
"pharmacologically-cifc;ctive amount" i~ used to represent an amount of the
onmpound of the
invention that is capabic of afFc.;aing the rnuluF;s, By afi;;cting, a
cornp:~urtd tit tim irtvc:rtzon it
atcting as an agc~nist or antagonist. When a compcwnd of the:
~1
CA 02328984 2000-10-16
Printed:l 2-10-2000
?8-07-1999 PCT/CA99/D0311 ~ 9 1SA-DESC26
PCTi /~A ~iuu~ls
JULY 1999 ~ 0 9 - 0 7 . 99)
invention acts as an agonist, the interaction of the compound with the
excitatory amino acid receptor
mimics the response ofthe interaction ofthis receptor with its natural ligand
(i.e. 1.-Glutamic acid).
When a compound of the invention acts as an antagonist, the interaction of the
compound with the
excitatory amino acid receptor blocks the response of the interaction of this
receptor with its natural 1
ligand (i.e. L-Glutamic acid).
The particular dose of compound administered according to this invention will,
of course, be
determined by the particular circumstances surrounding the case, including the
compound
administered, the route of administration, the particular condition being
treated, and similar
considerations. The compounds can be administered by a variety of routes
including oral, rectal,
transdermal, subcutaneous, intravenous, intramuscular, or intranasal routes.
Alternatively, the
compound may be administered by continuous infusion. A typical daily dose will
contain from about
0.001 mg/kg to about 100 mg/kg of the active compound of this invention.
Preferably, daily doses
will be about 0.05 mg/kg to about 50 mg/kg, more preferably from about 0.1
mg/lg to about 20
mg/kg .
A variety of physiological fiznctions have been shown to be subject to
influence by excessive or
inappropriate stimulation of excitatory amino acid transmission. The Formula I
compounds of the
present invention are believed (through their interactions at the mGIuRs) to
have the ability to treat
a variety of neurological disorders in mammals associated with this condition,
including acute
neurological disorders such as cerebral deficits subsequent to cardiac bypass
surgery and grafting,
cerebral ischemia (e.g. stroke and cardiac arrest), spinal cord trauma, head
trauma, perinatal hypoxia,
and hypoglycemic neuronal damage. The Formula I compounds are believed to have
the ability to
treat a variety of chronic neurological disorders, such as Alzheimer's
disease, Huntin~on's Chorea,
amyotrophic lateral sclerosis, AIDS-induced dementia, ocular damage and
retinopathy, cognitive
disorders, and idiopathic and drug-induced Parkinson's disease. The present
invention also provides
methods for treating these disorders which comprises administering to a
patient in need thereof an
effective amount of a compound of Formula I.
The Formula I compounds of the present invention (through their interactions
at the mGluRs) are
aisc believed to hive the ability tc tr °at a \'arl°t~' or
oth°- neurolo~i;,a' disorders it mammals t hat
are associated with glutamate dysfunction, including muscular spasms,
convulsions, migraine
headaches, urinary incontinence, psychosis, drug tolerance, withdrawal. and
cessation (i a opiates,
benzodiazepines, nicotine, cocaine, or ethanol), srnokin~ cessation, anxiety
and related disorders
(e g. panic attack), emesis, brain edema, clVOnic pain, sleep disorders,
Tourette's syndrome, attention
16
CA 02328984 2000-10-16 u- t _~ . . ...
Printed:l2-!V-GVVV ~ . r ~1' , ~ ~ ~ ~~.1 ; ..~
.. ~ ;. ~y . ~:''
1'
~8-07-1999 ~PCTlCA99/0031'1 p~-~ ~ C~ 9 g ~ ISA-DESC26
0 9 JULY 1999 CO 9 ~ 0 7 . 99J
deficit disorder, and tardive dyskinesia. Therefore, the present invention
also provides methods for
treating these disorders which comprise administering to a patient in need
thereof an effective
amount of the compound of Formula I.
The Formula I compounds of the present invention (through their interactions
at the mGIuRs) are
also believed to have the ability to treat a variety of psychiatric disorders,
such as schizophrenia,
anxiety and related disorders (e.g. panic attack), depression, bipolar
disorders, psychosis, and
obsessive compulsive disorders. The present invention also provides methods
for treating these
disorders which comprises administering to a patient in need thereof an
effective amount of a
compound of Formula I.
The pharmacological properties of the compounds of the invention can be
illustrated by determining
their effects in various functional in vitro assays. The compounds of the
invention were studied in
an in vitro assay that measured the inhibition of PI hydrolysis or the
formation of cyclic AMP in
Chinese hamster ovary cell lines expressing mGluRlQ, mGluRz and mGluR4, cloned
metabotropic
glutamate receptors.
Principle
So far eight different clones of the G-protein-coupled mGluRs have been
identified (Knopfel et al ,
1995, J. Med Chem., 38, 1417-1426). These receptors function to modulate the
presynaptic release
of L-Glutamate, and the postsynaptic sensitivity of the neuronal cell to L-
Glutamate excitation.
Based on pharmacology, sequence homology and the signal transduction pathway
that they activate,
the mGluRs have been subclassified into three groups. The mGluRl and mGluRS
receptors form
group I. They are coupled to hydrolysis of phosphatidyfinositol (PI) and are
selectively activated by
(RS)-3,5-dihydroxyphenylglycine (Brabet et al., Neuropharmacology, 34, 895-
903,.1995). Group
II comprises mGluR2 and mGluR3 receptors. They are negatively coupled to
adenylate cyclase and
are selectively activated by (2S,1'R,2'R,3'R)-2-(2,3-
dicarboxycyclopropyl)glycine (DCG-IV; Hayashi
et al., Nature, 366, 687-690, 1993). Finally, the mGluR4, mGluR~, mGluR~ and
mGluRs receptors
belong to group III. They are also negatively coupled to adenylate cyclase and
are selectively
a;,ti~~ate~ h~~ ~S'-?-amine-4-nhosph~m~lbut~-ric acid (L-:4P4; Knopfel. e~
al., ' 995. J. .Ailed Chem
38, 1417-1426).
!7
CA 02328984 2000-10-16
°Printedl2-10-2000 ~~ ~~ ~ ~ -. . . ~ ~ ~ .. ~ .._. '"~ ~~ 1.7''
28-07-1999 'PCT/CA99/00311 ~~-~- / ~~ 4 9 / ISA-DE5C26
Cell Culture
The Chinese hamster ovary cell lines expressing mGIuR~Q, mGluRz and mGIuR4~
receptors have been
described previously (Aramori and Nakanishi, Neuron 8, 757-765; 1992; Tanabe
et al., Neuron 8,
169-179, 1992; Tanabe et al., J. Neurosci. 13, 1372-1378). They were
maintained at 37°C in a
humified 5% COZ incubator in Dulbecco's Modified Eagle Medium (DMEM)
containing a reduced
concentration of (S}-glutamine (2mlV~ and were supplemented with 1% proline,
penicillin (100
U/ml), streptomycin (100 mglml) and 10% dialyzed fetal calf serum (all GIBCO,
Paisley). Two days
before assay 1.8 x 106 cells were divided into the wells of 24 well plates.
Second Messenger Assays
PI hydrolysis was measured as described previously (Hayashi et al., Br. J.
Pharmacol. 107, 539-543,
1992; Hayashi et al., J. Neurosci. 14, 3370-3377, 1994). Briefly, the cells
were labeled with
['I-i~inositol (2 pCi/ml) 24 h prior to the assay. For agonist assays, the
cells were incubated with
ligand dissolved in phosphate-buffered saline (PBS)-LiCI for 20 min, and
agonist activity was
determined by measurement of the level of'H-labeled mono-, bis- and tris-
inositol phosphates by
ion-exchange chromatography. For antagonist assays, the cells were
preincubated with the ligand
dissolved in PBS-LiCI for 20 min prior to incubation with ligand and 10 p.M
(L)-Glutamic acid for
20 min. The antagonist activity was then determined as the inhibitory effect
of the (L)-Glutamic acid-
mediated response. The assay of cyclic AMP formation was performed as
described previously
(Hayashi et al., Br. J. Pharnracol. 107, 539-543, 1992; Hayashi et al., J.
Neurosci. 14, 3370-3377,
1994). Briefly, the cells were incubated for 10 min in PBS containing the
ligand and 10 ~M forskolin
and 1mM 3-Isobutyl-1-methyxanthine (IBMX; both Sigma, St. Louis, MO, USA). The
agonist
activity was then determined as the inhibitory effect of the forskolin-induced
cyclic AMP formation.
For antagonist assay, the cells were preincubated with ligand dissolved in PBS
containing 1 mM
IBMX for 20 min prior to a 10 min incubation in PBS containing the ligand, 20
pM (mGluR2) or 50
uIJ (m iiur~,}, (L,i-:Tiutami;, acid, lu- uiJ ~ orsi:oiin any i rr>Tv IBlvi:~:
Results
Some of the compounds of the invention were tested for antagonist activity
against Chinese hamster
18
CA 02328984 2000-10-16
Printed:l 2-1 U-~UUU ', y~ Lv. 4__ I. ; ~., s_ _ , v__ _. ; :. ~~- ~.~ ~ ~ g
28-07=1999 PCT/CA99/003'11 PCs. ~ ~~ 9 g I ISA-DESC26
' ~9 ;IULY 1999 (0 9 ~ 07.99)
ovary cell lines expressing mGluRrQ, mGluR2 and mGiuR~, cloned mGluRs at a
concentration of
1 mM. When tested as antagonists of the increase in PI hydrolysis evoked by 10
~.tM (L)-Giutamic
acid, some compounds of the invention effectively blocked this increase in PI
hydrolysis by an action
at the mGluR,~ receptor. The data for one of the compounds of the invention is
shown in Figure 1
below.
According to another aspect, the present invention provides a method of
modulating one or more
metabotropic glutamate receptor functions in a warm-blooded mammal which
comprises
administering an effective amount of a compound of Formula I, or a non-toxic
metabolically-labile
ester or amide thereof, or a pharmaceutically acceptable salt thereof.
The compounds of the present invention are preferably formulated prior to
administration.
Therefore, another aspect of the present invention is a pharmaceutical
formulation comprising a
compound of Formula I and a pharmaceutically-acceptable carrier, diluent, or
excipient The present
pharmaceutical formulations are prepared by known procedures using well-known
and readily
available ingredients. In making the compositions of the present invention,
the active ingredient will
usually be mixed with a carrier, or diluted by a carrier, or enclosed within a
carrier, and may be in
the form of a capsule, sachet, paper, or other container. When the carrier
serves as a diluent, it may
be a solid, semi-solid, or liquid material that acts as a vehicle, excipient,
or medium for the active
ingredient
The compounds of Formula I are usually administered in the form of
pharmaceutical compositions.
These compounds can be administered by a variety of routes including oral,
rectal, transdermal,
subcutaneous, intravenous, intramuscular, and intranasal. These compounds are
effective as both
injectable and oral compositions. Such compositions are prepared in a manner
well known in the
pharmaceutical art and comprise at least one active compound.
The present invention also provides pharmaceutical compositions containing
compounds as disclosed
in the claims in combination with one or more pharmaceutically acceptable,
inert or physiologically
a:,tiv°. aiiu°n~ or adit!van:. ':~h° compound: o~
th° invention can bfreez°-dri°~and, i' d°sired.
combined with other pharmaceutically acceptable excipients to prepare
formulations for
administration. These compositions may be presented in any form appropriate
for the administration
route envisaged The parenteral and the intravenous route are the preferential
routes for
administration
19
CA 02328984 2000-10-16 ~ -.- c5-n ~ .rs,s ~ G'~ ~''~' 'Y. ~~~ s_~' ~ ~
Printed: ~ 2-10-2000 ~~ ~l ~ ~ ~ ~ ~ ~ ~ °~'" ~ ~ 1 g
_ o
28-0?-1999 PCT/CA99/00311 p~~-~- p ~~ ~ g / 1SA-DESC26
~9 JULY 1999 09 ° ~7~~~D)
C
Compounds of the general Formula I may be administered orally, topically,
parenterally, by
inhalation or spray or rectally in dosage unit formulations containing
conventional non-toxic
pharmaceutically acceptable carriers, adjuvants and vehicles. The term
parenteral as used herein
includes subcutaneous injections, intravenous, intramuscular, intrasternal
injection or infusion
techniques. In addition, there is provided a pharmaceutical formulation
comprising a compound of
general Formula I and a pharmaceutically acceptable carrier. One or more
compounds of general
Formula I may be present in association with one or more non-toxic
pharmaceutically acceptable
carriers and/or diluents and/or adjuvants and if desired other active
ingredients, The pharmaceutical
compositions containing compounds of general Formula I 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 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, flavouring agents,
colouring 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 that
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
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
o- l:aolir:: o- 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 active materials in admixture v~~ith excipients
suitable for the
manufacture of aqueous suspensions Such excipients are suspending agents, for
example sodium
CA 02328984 2000-10-16 , E., ~:, . , a.r:~.- l., f; 'b j 4~" ~' ~ i~ ~ 3
Printed:l2=10-2000. ~ y- ~~ i ~ ~ . ~~'r '_ . ' ... ~- ~ 2p
28-07-1999 PCT/CA99/0031 y P~,~ ~ ~~ 9 9 f ~IS~1-DESC26
°4To~~~
carboxylmethylcellulose, methyl cellulose, hydropropylmethylcellulose, sodium
alginate,
polyvinylpyrrolidone, 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 hepta-decaethyleneoxycetanol,
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 rt-propyl-
p-hydroxy benzoate, one or more colouring agents, one or more flavouring
agents or one or more
sweetening agents, such as sucrose or saccharin.
Oily suspensions may be formulated by suspending the active ingredients in a
vegetable oil, for
example peanut oil, olive oil, sesame oil or coconut oil, or in a 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 flavouring
agents may be added to
provide palatable oral preparations. These compositions may be preserved by
the addition ofan 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 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,
flavouring and colouring agents, may also be present.
Pharmaceutical compositions of the invention may also be in the form of oil-in-
water emulsions. The
oil phase may be a vegetable oil, for example olive oil or peanut oil, or a
mineral oil, for example
liquid paraffin or mixtures of these. Suitable emulsifying agents may be
naturally-occurring gums,
for example gum acacia or gum tragacanth, naturally-occurring phosphatides,
for example soy bean,
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
2l
... - °.~-.;: y
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28-07-1999 PCT/CA99/00311 ~ ~~ ~ ~ ~~ ~ ~ .1SA_DESC2G'
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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
flavouring and colouring agents. The pharmaceutical compositions may be in the
form of a sterile
injectable aqueous or oleaginous suspension. This suspension may be formulated
according to
known art using those suitable dispersing or wetting agents and suspending
agents that have been
mentioned above. The sterile injectable preparation may also be a sterile
injectable solution or a
suspension in a non-toxic parentally acceptable diluent or solvent, for
example as a solution in 1,3-
butanediol. 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.
The compounds) of the general Formula I may be administered, together or
separately, in the form
of suppositories for rectal administration of the drug. These compositions can
be prepared by mixing
the drug with a suitable non-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.
Compounds) of general Formula I may be administered, together or separately,
parenterally in
sterile medium. The drug, depending on the vehicle and concentration used, can
either be suspended
or dissolved in the vehicle. Advantageously, adjuvants such as local
anaesthetics, preservatives and
buffering agents can be dissolved in the vehicle.
The dosage to be administered is not subject to defined limits, but it will
usually be an effective
amount. It will usually be the equivalent, on a molar basis of the
pharmacologically active free form
produced from a dosage formulation upon the metabolic release of the active
free drug to achieve
its desired pharmacological and physiological effects. The compositions are
preferably formulated
in a unit dosage form, each dosage containing from about 0.05 to about 100 mg,
more usually about
1.0 to about 30 mg, of the active ingredient. The term "unit dosage form"
refers to physically
discrete units suitable as unitary dosages for human subjects and other
mammals, each unit
containing a predetermined quantity of active material calculated to produce
the desired therapeutic
°f'~r°ct. in asso,iation with a suitable phar~nac°utical
excipi~nt
22
~ 02328984 2000-10-16 ~~ '.- ~~ - ~ , ; ~ , - . . . ,. ...< Li
Printed:l2-10-2000
28-07-1999 PCT/CA99/00311 PCs, ' ~~ 9 g ~ISA-DESC26
d 9 JI~LY 1999 ~ 0 9 - 0 7 . 99 ,
The active compound is effective over a wide dosage range. For examples,
dosages per day normally
fall within the range of about 0.01 to about 30 mgJkg of body weight. A
typical daily dose will
contain from about 0.01 mg/kg to about 100 mg/kg of the active compound of
this invention.
Preferably, daily doses will be about 0.05 mg/kg to about 50 mg/kg, more
preferably from about 0.1
mg/kg to about 25 mg/kg. In the treatment of adult humans, the range of about
0. I to about 1 S
mg/kg/day, in single or divided dose, is especially preferred. However, it
will be understood that
the amount of the compound actually administered will be determined by a
physician, in the light of
the relevant circumstances, including the condition to be treated, the chosen
route of administration,
the actual compound administered, the age, weight, and response of the
individual patient, and the
severity of the patient's symptoms, and therefore the above dosage ranges are
not intended to limit
the scope of the invention in any way. In some instances dosage levels below
the lower limit of the
aforesaid range may be more than adequate, while in other cases still larger
doses may be employed
without causing any harmful side effect, provided that such larger doses are
first divided into several
smaller doses for administration throughout the day.
The compositions are preferably formulated in a unit dosage form, each dosage
containing from
about 5 mg to about 500 mg, more preferably about 25 mg to about 300 mg of the
active ingredient.
The term "unit dosage form" refers to a physically discrete unit suitable as
unitary dosages for human
subjects and other mammals, each unit containing a predetermined quantity of
active material
calculated to produce the desired therapeutic effect, in association with a
suitable pharmaceutical
carrier, diluent, or excipient The following formulation examples are
illustrative only and are not
intended to limit the scope of the invention in any way
23
~ 02328984 2000-10-16 ., .
Printed:l2-10-2000 ~ .. ~... ; '~ ,
28-07-199~J PCT/CA99/00317 ISA-DESC26'
r'°yCT ~ ~'o~ ~ ~ r a v . . m
Formulation 1
Hard gelatin capsules are prepared using the following ingredients:
Quantity (mg/capsule)
Active Ingredient 250
Starch, dried 200
Magnesium stearate 10
Total 460
The above ingredients are mixed and filled into hard gelatin capsules in 460
mg quantities
Fornuclation 2
A tablet is prepared using the ingredients below:
Quantity (mg/tablet)
Active Ingredient 250
Cellulose, microcrystalline 400
Silicon dioxide, fumed 10
Stearic acid 5
Total 665
The components are blended and compressed to form tablets each weighing 665
mg.
Fornxulal~ion 3
An aerosol solution is prepared containing the following components:
24
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28-07-1999 PCT/CA99/00311- 15A-DESC26 '°
P C'~' / ~A ° 9 / 0 0 31 ~
J~~'~ 19~g C(~ 9 ~ a ~ _ ~~
l
Weight
Active Ingredient 0.25
Ethanol 29.75
Propellant 22 (Chlorodifluoromethane) 70.00
Total
100
The active compound is mixed with ethanol and the mixture added to a portion
of the Propellant 22,
cooled to -30 °C and transferred to a filling device The required
amount is then fed to a stainless
steel container and diluted with the remainder of the propellant. The valve
units are then fitted to
the container.
Forntulaiion 4
Tablets each containing 60 mg of active ingredient are made as follows:
Quantity (mgltablet)
Active Ingredient 60
Starch 45
Microcrystalline cellulose ~5
PolyvinylpyrroIidone 4
Sodium carboxymethyl starch 4.5
Magnesium stearate 0 5
Talc
1.0
Total
150
The active ingredient, starch, and cellulose are passed through a No. 45 mesh
U.S. sieve and mixed
thoroughly. The solution of polyvinylpyrrolidone is mixed with the resultant
powders that are then
passed through a No. 14 mesh U.S sieve. The granules so produced are dried at
~0°C and passed
Printed:l 2 1 ~ ;,~.,._ , , . : .. _ . _. ,
CA 02328984 2000-10-16 r.=, . ; ,
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28-07-1999 PCT/CA99/00311 I SA-~DESC26
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0 9 'JUDY 1999 0 9 - 0 7 . 99,
through a No. 18 mesh U.S. sieve. The sodium carboxymethyi starch, magnesium
stearate, and talc,
previously passed through a No. 60 mesh U.S. sieve, are then added to the
granules which, after
mixing, are compressed on a tablet machine to yield tablets each weighing 1 SO
mg.
Formulation S
Capsules each containing 80 mg medicament are made as follows:
Quantity (mg/capsufe)
Active Ingredient 80
Starch 59
Microcrystalline cellulose 59
Magnesium stearate 2
Total 200
The active ingredient, cellulose, starch, and magnesium stearate are blended,
passed through a
No. 45 sieve, and filled into hard gelatin capsules in 200 mg quantities.
Formulation 6
Suppositories each containing 225 mg of active ingredient may be made as
follows:
Quantity (mg/suppository)
Active Ingredient 225
Saturated fatty acid glycerides 2000
Total 2225
The active ingredient is passed through a No 60 mesh U.S. sieve and suspended
in the saturated
fatty acid giycerides previously melted using the minimum heat necessary. The
mixture is then
poured into a suppository mold of nominal 2 g capacity and allowed to cool '
26
CA 02328984 2000-10-16
Printed:l 2-10-2000 ~~, c ~; ~:. rw ~ ~ 1- ,;- r. l~ ~ j r~-- - , Y ~- '; ;'
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28-Ors-1999 PCT/CA99/00311 ~~~ ! ~~ 9 9 ~ ISA-DESC26
09 JULY 1999 (D 9 - 0 7 . 9g
Formulation 7
Suspensions each containing 50 mg of medicament per 5 mI, dose are made as
follows:
Active Ingredient 50 mg
Sodium carboxyimethyl cellulose 50 mj
Syrup 1.25 mL
Benzoic acid solution 0.10 mL
Flavour q. v.
Color q.v.
Purified water to total 5 mL
The medicament is passed through a No. 45 mesh U. S. sieve and mixed with the
sodium
carboxymethyl cellulose and syrup to form a smooth paste. The benzoic acid
soiution, flavor and
color are diluted with some of the water and added, with stirring. Suf~'~cient
water is then added
to produce the required volume.
Formulation 8
An intravenous formulation may be prepared as follows:
Quantity
Active Ingredient 100 mg
Mannitol 100 mg
N Sodium hydroxide 200 mL
Purified water to total ~ 5 ~,
Formulation 9
A topical formulation may be prepared as follows
27
CA 02328984 2000-10-16 _
Printed:l 2-10-2000 .~ ~ ~ r ~ ~~ ~ ~' c~ r ~~ ~ ~'" iL....~ ~ ~ ~..: ~~
c8-07-1999 PCTlCA99/00311 ~~~ , C~ 9 9 / ISA-DESC26
°
Quantity
Active Ingredient 1-10 g
Emulsifying Wax 30 g
Liquid Paraffin 20 g
White soft parafftn to 100 g
The white soft para$'tn is heated until molten. The liquid paraffin and
emulsifying wax are
incorporated and stirred until dissolved. The active ingredient is added and
stirring is continued
until dispersed. The mixture is then cooled until solid.
Formulation 1 D
Sublingual or buccal tablets, each containing 10 mg of active ingredient, may
be prepared as
follows:
Quantity (mg/tablet)
Active Ingredient 10.0
Glycerol 210.5
Water 143.0
Sodium Citrate 4.5
Polyvinyl Alcohol 26 5
Polyvinylpyrrolidone 15. 5
Total 410 0
The glycerol, water, sodium citrate, polyvinyl alcohol, and
polyvinylpyrrolidone are admixed
together by continuous stirring and rnaintairung the temperature at about 90
°C. When the
polymers have gone into solution, the solution is cooled to about 50°-
55 °C and the medicament
is slowly admixed. The homogenous mixture is poured into forms made of an
inert material to
produce a drug-containing diffusion matrix havin;; a thickness of about 2-4
mm. This diffusion
matrix is then cut to form individual tablets having the appropriate size
28
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CA 02328984 2000-10-16
P.rinted:'Y2-10-200D
99 / p- '
28-07-1999 PCT/CA99/003'11 PCB / C~ ISA-DESC26 -
JULY 1999CO9~07.9gI
Another preferred formulation employed in the methods of the present invention
employs
transdermal delivery devices ("patches"). Such transdermal patches may be used
to provide
continuous or discontinuous infusion of the compounds of the present invention
in controlled
amounts.
The construction and use of transdermal patches for the delivery of
pharmaceutical agents is well
known in the art (see, for example, U.S. Pat No. 5,023,252, issued Jun. 11,
1991) herein
incorporated by reference. Such patches may be constructed for continuous,
pulsatile, or on
demand delivery of pharmaceutical agents.
Frequently, it will be desirable or necessary to introduce the pharmaceutical
composition to the
brain, either directly or indirectly. Direct techniques usually involve
placement of a drug delivery
catheter into the host's ventricular system to bypass the blood-brain barrier.
One such implantable
delivery system, used for the transport of biological factors to specific
anatomical regions of the
body, is described in U.S. Pat. No. 5,011,472, issued Apr. 30, 1991, which is
herein incorporated
by reference.
Indirect techniques, which are generally preferred, usually involve
formulating the compositions to
provide for drug latentiation by the conversion of hydrophilic drugs into
lipid-soluble drugs or
prodrugs. Latentiation is generally achieved through blocking of the hydroxy,
carbonyl, sulfate, and
primary amine groups present on the drug to render the drug more lipid soluble
and amenable to
transportation across the blood-brain barrier. Alternatively, the delivery of
hydrophilic drugs may
be enhanced by intra-arterial infusion of hypertonic solutions that can
transiently open the
blood-brain barrier.
EXAMPLES
The following Examples illustrate the invention. The following abbreviations
are used in the
Examples: EtOAc, ethyl acetate; THF, tetrahydrofuran; EtOH, ethanol; TLC, thin
layer
chromatography; GC, gas chromatography; HPLC, high pressure liquid
chromatography; m-CPBA,
m-chloroperbenzoic acid, Et~O, diethyl ether; DMSO, dimethyl sulfoxide; DBU,
1.8-diazabicyclo-
[5.4.0)undec-7-ene, MTBE, methyl t-butyl ether, FDMS, f eld desorption mass
spectrornetrv and
r t , room temperature. .
29
CA 02328984 2000-10-16 _ -..n .~ ~ ~ ~ rn . :a
Pr=inted:l 2-~ -~ ~;~ tt CJ..~-i ct.,.L- ~7 ~~I ~~ ~~~ ~ o,.
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. 29
z8-07-1999 PCT/CA99/0031'I ~~"~' / ~,4 y 9 ISi4-DESC26
0 9 JULY 1999 ~~ 9 - 0 7 . 99
Example 1: Synthesis of Cubanylglycinates IGT 1.0 series
a b
C -~ Me02C
~'~OOZMe ~OO~I
2 3
n
H02C CO~"1 MeOzC CN MeOzC
'"'H ~--- -~- ~CHO
a H d
4
Ph
OH .
Preparation l: 4-methoxycarbonylcubane carboxylic acid _
A solution of cubane dimethyl ester (6.Og, 27.24 mmol) in 182 mL of dry THF is
stirred under Nz
at room temperature. A solution of methanolic NaOH (26.7 mmol, 10.7 mL 2.5
Iv>) is added
dropwise from a pressure equalized addition funnel and the resulting solution
stirred at room
temperature for 16 h. The mixture is evaporated under reduced pressure at
r.t., the residue is taken
up in 66 mL of water and extracted with 3 x 25 mL of chloroform. The aqueous
layer is acidified
to pH 3 with concentrated HCl and extracted with 3 x 30 mL of chloroform. The
combined organic
layers were dried over magnesium sulphate, filtered and evaporated to give (2)
182-183 °C: 'H
NMR (CDCI;) 8 3.72 (s, 3H), 4.27 (m, 6H).
Yield 5 1 g (91%).
Pr-eparatior~ 2: 4-methoaycarbonyl-1-(hydrox~~rnethyl) cubane
The mono acid (2) (0 48 g) is dissolved in dr<- THF (5 mL) and cooled to -70
°C A solution of
BH: in THF is added slowly with stirring. The reaction mixture is stirred at -
78 °C for 4 hrs and
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20-07-:2000 ~ ~ PCT/CA99/00311 pFgC
allowed to come w rrtr~m temperature. Water (3 mL) is added and stirred for 30
rnin, potassium
carbonate (0.85 g) is added antl the solution exirdetcd with Ft,,O. 'fhc
organic phase is driai over
magnesitus? sulfate and evaporated to give the alc:ahol (3) 0.46 g (!00%) m.p.
83-85 °C. '~I
NMR(200IvII~~, solvent) c~: l.Sg (s, 11i), 3.62 (s, 3f1). 3,72 (s, 2H), 3.8t
(m, 31~), 4.1 (m, 3H).
Pre~xwadnn,?; 4-rnc;thoxycarfictnyt-1-(formyl) cubane
DA450 (0.7 mL. 9.68 mrtxtl) is added to s~xalyl chloride (0.42 mL, d.~ mmat)
in 12 mL afi Chi=CIz
at -7$ °C. 'fhc alcohol (3) (0.4G g. 2,42 rnmol) in 3 mL CH; CIZ is
addcxl and stirred at -78 °C for
t.5 h. '1'riethylamine (2.0 rnL, 14.4 mmol) is adddd and the miotur~ is
allowed to come to 0°C.
Saturated ammar<ium chloridre salutitrn is added and the phases separated,
thc~ dqutous layer is
extracted with CH,CI, and the c<mt~inetl organic layers are dcied (M$SfJ~),
then c,~-apr>rattxi to give
crude: prnduct which ir; purified by flash chromatc~~~raphy (i :1
hexanes:dicthyl ether) is give 0.35
g (7blo) of pure product (4). 'H NMR (200 M!-lr. solvent) 8: ,3.7 (s, 3H), d.Z
(m, 3H ), 4.32 (m.
3H), ~.~z (~.1JK).
Preparutiun 4: ~t-tncthc>xycat~uny-1-I~2'-hydroxy-1'-phenylcrhyl)
mothylnittilocubane
a
(R)-hhcnytglyeinol (2a7 mg. 1.87 mrnul) is added t~ a solution of the
aldehyde; (4) (0.35 g, 1.84
rntnot) in 14 mL. of methanol. 'T'tu, soluticm is cooiod to 0 "C and TNiSCN
(O.d9 inL, 3.68 mmoJ)
is added and the nuxeurc; stirred ai 0 °C overnight. F,vapordtion of
the solvent leaves a ncsidue
which is purifiotJ by chrz~matography (diethyl cther:hexancs, 3:1) to gise
G.48 g (77%) of pure
product {5). tIl NMR (C~UCI,~ b: 2.23 (s. l I-1.), 2.6 (br, llrl), 3.S-3.75
(m, 2H?, 3.7 (s, 31~). 3.9 (m.
3H), 4.1 i (dd. 1H), 4.2 (m, 311), 'l.3 (s, 5H).
Preparadion ~~ ~4-carboxy-1-cubanylglycine
Lead rtceta~tc (O.E~9 g, 1.57 mmt~t) is added W a stirred solution t>f niirile
(5) (G.48 g, 1.42 tnmol) in
dry methanc~tldichic~romcahane 1:L (1.2 mL). After 10 min IO mL of water is
added and the
suspension fittc:red thrt~ugh ectitc. 'fhe organic layer is dried and
euapr~rated to give the crude
inunc. The crude imine is refluxed with 6N HC.I (30 mL) for 6 hr. The
solutiorl i.5 evaporated tn
dryness and ptaeEd cm anicyn exchange resin, elating with IN acetic acid to
yield the prc~d~uct (6).
rnp. 241 °-C', (dcc;.) lIi rilMlZ (DZU) b 3.9G (s, 1H), 4.01 (m, 3H),
4.14 Lm, 3t-1).
31
CA 02328984 2000-10-16
Printed:l 2-~ U-~~UU g
28-07-199 PCT/CA99/003"I'1 ISA-DESG26
PC'6'/CA ~9~ v
~ 9 ;lt.~Ll~ aa~g (.0 9 - 0 ~ ° 99'~
Example 2
Me02C Me02C Me02C MeO2C
--
COzMe C02H
COCI 4 O
H02C MeOzC
' N '.0
COZH - IIN~H
H2N ~ Ol
Preparation l: 4-methoxycarbonylcubane carboxylic acid
A solution of cubane dimethyl ester (6.Og, 27.24 mmol) in 182 mL of dry THF is
stirred under N2 at
r.t. a solution of methanolic NaOH (26 7 mmol, 10.7 mL 2 S 1V>7 is added
dropwise from a pressure
equalised addition funnel and the resulting solution stirred at r.t. for 16 h.
The mixture is evaporated
under reduced pressure at r.t., the residue is taken up in 66 mL of water and
extracted with 3 x 25
mL of chloroform. The aqueous layer is acidified to pH 3 with concentrated HCl
and extracted with
3 x 30 mL of chloroform. The combined organic layers were dried over magnesium
sulphate, filtered
and evaporated to give (2) 182-183 °C: 1H NMR (CDCl3) 8 3.72 (s, 3H),
4.27 (m, 6H).
Yield 5.1 g (91 %).
Preparation 2: 4-methoxycarbonylcubane-1-carbonyl chloride
The monomethyl ester (2) (1.37 g, 6 65 mmol) is dissolved in 1~ mL ofthionyl
chloride and
Qently refluxed overnight. The thionyl chloride is evaporated off and the
resultant residue
containing (3 j was used immediately without further purincation.
32
CA 02328984 2000-10-16 '' ' ' ' . ... , ~ .~ ..._, r
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28-07-1999 PCT/CA99/00311 ~C.~. ~ ~~ o g ISA-DE5C26
JULY 1999 (0 9 ~ 07. gg1
Preparation 3: 4-methoxycarbonylcubane-1-methyl ketone
A suspension of copper iodide (1.49 g, 7.83 mmol) in 30 mL of dry THF is
stirred at 0°C
Methyl lithium (15.75 mmol, 11.2 mL of 1.4 M) was added and stirred at
0°C for 30 min, then
cooled to
-78°C. A solution of 1.6 g, 7.12 mmol of (3) in 10 mL dry THF is added
and the resultant
mixture stirred for 1 h. at -78°C. The mixture was quenched with
saturated ammonium chloride
solution (15 mL) and extracted with 3 x 30 mL of diethyl ether. The combined
organic layers
were dried over magnesium sulphate, filtered and evaporated to give crude (4).
The product
was purified by silica chromatography (hexanes:ethyl acetate, 2:1 ) to give
1.0 g of product
(yield 69%). m.p. 87-89°C. 'H NMR (CDC13) 8 2.17 (s, 3H), 3.7 (s, 3H),
4.21 (m, 6H).
Preparation -~: 4-methoxycarbonylcubane-1-methyl-1-(5,5'-hydantoin)
A solution of the methyl ketone (4) (1.0 g, 4.9 mmol) in 40 mL of ethanol and
5 8 mL of 1 N
NaOH, is stirred at 70°C for 4 h. The resulting solution is evaporated
to dryness under reduced
pressure and redissolved in 1 1 ethanol: water (20 mL). To this solution is
added potassium
cyanide (0.35 g, 5.4 mmol) and ammonium carbonate (0.96 g, 9.8 mmol) and the
mixture
heated in a sealed tube at 85°C for 24 h. The reaction is cooled,
acidified with 6 N HCl and
reduced in volume until a precipitate forms. The precipitate is filtered and
the filtrate
evaporated to dryness and extracted with ethyl acetate. The solvent is
evaporated and. the
product combined with the residue from above to give (S) as a white solid.
Yield 0.95 g (75%)
m.p. 244-248°C. NMR'H (DMSO) S 1.18 (s, 3H) 3.9 (m, 3H), 4.0 (m, 3H), 8
1 (s, 1H), 10.6
(s, 1 H).
Preparation 5: 4-carboxycubane-1-methylglycine
The hydantoin (5) (0.95 g, 3.65 mrnol) is dissolved in 30 mL of 2 N NaOH and
heated to 170°C
in a sealed tube for 20 h. The reaction is cooled and filtered to remove
precipitate and the filter
cake washed with 3 x 10 mi. of water. The combined aqueous washings are
evaporated to Qive
crude (6) which is applied to Spectrum 1 X4 anion exchange resin, eluted with
0 ~ N acetic acid.
Isolation by evaporation and crystallization Gives (6) as colorless crystals.
m.p. >250°C
(decomp ) NMR. 'H (DZO) 0 1 38 (s. 3H), 3 95 (s, 6H)
-
JJ
CA 02328984 2000-10-16
Printedl2-10-2000 ;~ ; ~ :.=~ . ,:~,~:,--~. ~-~~.. .. . 33
28-07-1999 ~ PCT/CA99/00311 1SA=DESC26
PAC-riCA 99/0031 ~
09 JULY 1999 C09-67.qg)
Example 3
MeOZC Me02C
COCI 'COzEt
2 O - U I:VZC.t
H02 HOZ
4
Preparation l: 4-methoxycarbonylcubane-1-acet3rl ethylcarboxylate.
n-butyl lithium (34.83 mmol, 23.5 mL of 1.5 1Vn is added dropwise to a stirred
solution of ethyl
hydrogen malonate (2.32 g, 17.41 mmol) in 80 mL of dry THF under Nz at -
78°C. The mixture
was warmed to -30°C over 0.5 ~h and then re-cooled to -78°C. The
acid chloride of cubane
monomethyl ester from example (2) above (2.35 g, 10.46 mmol) in 7 mL of THF is
added
dropwise to the stirred solution. The reaction is warmed slowly to r.t and
stirred for a further 1 h.
The solution is poured into 50 mL of 1 N HCI and extracted with 3 x 50 mL of
diethyl ether.
The combined organic extracts are further extracted with 20 mL of saturated
sodium hydrogen
carbonate and brine, dried over magnesium sulphate, filtered and evaporated to
give crude (2).
The product is purified by column chromatography on silica with hexanes: ethyl
acetate 2:1 to
yield 2.5 g (86%) of (2). LH NMR (CDCI3) 8 1.2 (t, 3H) 3.4 (s, 2H), 3.65 (s,
3H), 4.2 (m, 8H).
34
CA 02328984 2000-10-16 ~' y ~: ' . ;\ ;. -' ' ' , , ; ~. ~ ~ L _ ..
P~rinted:l 2-7 0-2000: ~: v~ ~-- c~~ ~ ~ ~., ~~~= ~ ~ ~ w'~'~ ~ 34
28-07-1999 P~TlCA99/00311 ~~'~ ~ ~~ 9 g i ISA-'DESC26
:IlILY 19991,09-07.99~~
Preparation 2: 4-methoxycarbonylcubane-1-(thioxanthyl)-acetyl
ethylcarboxylate.
cubane-~i-ketoester (2) (1.158, 4.16 mmol) and thioxanthene-9-of (0.88g, 4.1
mmol) are
dissolved in 18 mL of a 1:1 mixture of ethanol:acetic acid and stirred at r.t.
for 3 days. The
resulting crystalline solid was filtered offto yield 1.52 g (77%) of pure (3)
m.p. 147-149°C. 'H
NMR (CDCI;) 1 00 (t, 3H), 3.24 (s, 3H), 3.75 (m, 3H), 3.9 (q, 2H), 4.0 (m, 3H,
4.6 (d,
1 H), 5. 0 (d, 1 H), 7. 3 (m, 8H).
Preparation 3' 4-carboxycubane-I-methylthioxanthylketone
The thioxanthylcubane adduct (3) (1.69 g, 3.57 mmol) is dissolved in ethanol
33 mL and 8.7 mL
of I N NaOH and heated at 70°C for 4 h. The resulting solution is
evaporated and redissolved
in 25 mL of water, acidified with 6 N HCl and extracted with 3 x 50 mL of
diethyl ether. The
combined organic layers are dried over magnesium sulphate, filtered and
concentrated to give a
crude product containing (4). Chromatography on silica using ethyl acetate
gives 1.26 g (88%)
of (4)
'H NMR (CDCI;) 8 2.8 (d, 2H), 3.8 (m, 3H), 4.0 (m, 3H), 4.7 (t, 1H), 7.3 (m,
8IT), 9.5 (br,
1H).
Preparatiorr ~f: 4-carboxycubane-I-thioxanthyl-I-(S,5'-hydantoin)
The thioxanthyl cubane ketone (4) (1.24 g, 3.22 mmol) is dissolved in 1 I
ethanol:water (20
mL). Potassium cyanide (0.522 g, 8.0 mmol) and ammonium carbonate ( 1.39 g,
14.4 mmol) are
added and the solution heated in a sealed tube at 85°C for 65 h The
reaction is cooled and
acidified with 2 N HC1 and extracted with 3 x 40 mL of ethyl acetate. The
organic layers are
combined, dried over magnesium sulphate, filtered and evaporated to give (5)
1.3 g (88%) as a
crude product. This material was hydrolyzed in the next step without
purification.
'H NMR (CD;OD) 8 1.7 (m, IH), 2.7 (m, 1H), 3.8 (m, 3H), 4.0 (m, 3H), 4.3 (m,
1H), 7.4
(m, 8H).
PrepcrJOruorr ~: 4-carboxycubane-1- thioxanthyl lglycine
~ 02328984 2000-10-16
Printed:l2=10-2000 ~''~ ~~ ~" 3~
28-07-1999 PCT1CA99/00311 ISA-D~SC26
PST ! CA 9 9 . ~ ~ . _ _
~9 ;IULY 1999 (09-07_991
l
The hydantoin adduct (5) (300 mg, 0.65 mmol) is taken up in 1 N NaOH (10 mL)
and heated at
170 °C for 20 h in a sealed tube. The mixture is cooled and the pH
adjusted with 6 N HCl to
between 7 and 8. The precipitate formed is filtered and washed with water. The
combined
filtrate and washings are combined and evaporated to dryness. The resulting
residue is purified
by column chromatography and finally by reverse phase chromatography to yield
(6) as
colorless crystals. 70 mg. 'H NMR (CD30D + 020) b 2.3 (m, 2H), 3.9 (s, 6H), 4
4 (m, l H),
7.4 (m, 8H)
36
CA 02328984 2000-10-16 ~' ~~. ~ 1y ~ lt,,
Printed:l 2-10-2000' ~'' '.36.
