Note: Descriptions are shown in the official language in which they were submitted.
WO 91/16888 PCr/US91/02419
2 û ~
SPIRO[BENZOFURANCYCLOALKANE]-
CARBOXAMIDES AS 5HT~ ANTA~iON!STS
,
Background of the Invention
1 0
This application is a continuation-in-part application of U.S. Serial No.
07/512,709 filed April 23, 1990.
Field of the Invention
1 5
This invention is directed to novel compounds and their valuable use as
pharmaceutical agents as 5HT3 antagonists having unique central nervous
system, anti-emetic and gastric prokinetic activity void of any significant D2
receptor binding properties. This invention also describes novel processes
2 0 necessary for their preparation.
Spiro[benzofurancycloalkane]carboxamide substituted compounds
which exhibit 5HT3 antagonists properties including CNS, anti-emetic and
, gastric prokinetic activity which are void of any significant D2 receptor binding
2 5 affinity. This invention also relates to pharmaceutical compositions and
methods for the treatment of gastroinstestinal and mental disorders using said
compounds. This invention also describes novel processes for their
preparation. -; -
3 0 5-Hydroxytryptamine, abbreviated "5HT", is commonly known as
serotonin. Serotonin is found throughout the body including the
gastrointestinal tract, platelets, spleen and brain, and appears to be involved in -
a great number of physiological processes such as a neurotransmitter at
certain neurones in the brain, and is implicated in a number of central nervous
3 5 system (CNS) disorders. Additionally, serotonin appears to act as a local
hormone in the periphery: it is released in the gastrointestinal tract, where itincreases small intestinal motility, inhibits stomach and colon motility, and
WO 91/16888 PC~/IJS91/02419
2 0 g ~
. 2
stimulates stomach acid production. Serotonin is most likely involved in
normal intestinal peristalsis.
. The various physiological activities exerted by serotonin are related to
5 the variety of different receptors found on the surface membrane of cells in
different body tissue. The first classification of serotonin receptors included two
pharmacologically distinct receptors discovered in the guinea pig ileum. The
"D" receptor mediates smooth muscle contraction and the "M" receptor involves
the depolarization of cholinergic nerves and release of acetylcholine. Three
10 different groups of serotonin receptors have been identified and the following
assignment of receptors has been proposed: D-receptors are 5HT2-receptors;
M-receptors are termed 5HT3-receptors; and all other receptor, which are
clearly not 5HT2 or 5HT3, should be referred to as 5HT1-like.
5HT3-receptors have been located in non-neurological tissue, brain
tissue, and a numbr of peripheral tissues related to different responses. It has. been reported that SHT3-receptors are located on peripheral neurones where
they are related to serotonin's (excitatory) depolarizing action. The following
subtypes of 5HT3 receptor activity have been reported: 5HT3B subtype
2 0 involving postganglionic sympathetic and parasympathetic neurones, leading
to depolarization and release of noradrenaline and acetylcholine, respectively;
:; 5HT3C subtype involving on enteric neurones, where serotonin may modulate
the level of acetylcholine; and 5HT3A subtype involving on sensory nerves
such as those involved in the stimulation of heart nerve endings.to produce a
2 5 reflex bradycardia, and also in the perception of pain.
,,
Highly selective 5HT3-antagonists have been shown to be very effective
at controlling and preventing emesis (vomiting) induced by chemotherapy and
- radiotherapy in cancer patients. The anti-emetic effects of 5HT3-antagonists in
3 0 animals exposed to cancer chemotherapy or radiation are similar to those seen
following abdominal vagotomy. The antagonist compounds are believed to act
by blocking SHT3-receptors situated on the cell membranes of the tissue
forming the vagal afferent input to the emetic coordinating areas on the brain
stem.
Serotonin is also believed to be involved in the disorder known as
migraine headache. Serotonin released locally within the blood vessels of the
~ . .
- ,......
'
W O 91/16888 2 ~ ~ ~ O ~ ~ PC~r/US91/02419
~ i.. l 3
:
head is believed to interact with elements of the perivascular neural plexus of
which the afferent, substance P-containing fibers of the trigeminal system are
believed relevant to the condition. By activating specific sites on sensory
neuronal terminals, serotonin is believed to generate pain directly and also
5 indirectly by enhancing the nociceptive effects of other inflammatory mediators,
for example bradykinin. A further consequence of stimulating the afferent
neurones would be the local release of substance P and possibly other
sensory mediators, either directly or through an axon reflex mechanism, than
providing a further contribution to the vascular changes and pain of migraine.
1 0 Serotonin is known to cause pain when applied to the exposed blister base orafter an intradermal injection; and it also greatly enhances the pain response to
bradykinin. In both cases, the pain message is believe to involve specific 5HT3
receptor on the primary afferent neurones.
1 5 5HT3-antagonists are also reported to exert potential antipsychotic
effects, and are believed to be involved in anxiety. Although not understood
well, the effect is believed to be related to the indirect blocking of serotonin; 5HT3-mediated modulation of dopamine activity.
Many workers are investigating various compounds having 5HT3-
antagonist activity. -
Reported Developments
2 5 The development of 5HT3 agents originated from work carried out with
metoclopramide (Beecham's Maxolon, A.H. Robins' Reglan), which is
marketed for use in the treatment of nausea and vomiting at high doses.
Metochlopramide is a dopamine antagonist with weak 5HT3-antagonist
activity, which becomes more prominent at higher doses. It is reported that the
3 0 5HT3 activity and not the dopamine antagonism is primarily responsible for its
anti-emetic properties. Other workers are investigating this compound in
connection with the pain and vomiting accompanying migraine.
Merrell Dow's compound MDL-72222 is reported to be effective as an
3 5 acute therapy for migraine, but toxicity problems have reportedly ended work
on this compound. Currently four compounds A.H. Robins' Zacopride,
Beecham's BRL-43694, Glaxo's GR-38032F and Sandoz' ICS-205-930 are in
- . - , - -
- ~ ~ - , - , ~ ,,
., ~ ~ ,. . .
WO 91/16888 2 0 ~ 1 ~ 3. ~ PCI-/US91/C2419
clinical trials for use in chemotherapy-induced nausea and vomiting. GR-
38032F is also in clinical trials for the treatment of anxiety and schizophrenia.
Zacopride is repor~ed to be in clinical trials for anxiety, while ICS-205-930 isreported useful in the treatment of carcinoid syndrome.
Compounds reported as gastroprokinetic agents include Beecham's
BRL-24924, which is a serotonin-active agent for use in gut motility disorders
such as gastric paresisl reflux esophagitisl and is known to also have 5HT3-
antagonist activity.
1 0
Metoclopramidel Zacopridel Cisapride and BRL-24924 are
characterized by a carboxamide moiety situated para to the amino group of 2-
chloro-4-methoxy aniline. BRL-436941 ICS-2059301 GR-38032F and GR-
65630 are characterized by a carbonyl group in either the 3-position of indole
1 5 or N-benzoatel while Zacopridel BRL-24924, BRL-43694, ICS-205930 have
also bridged azabicyclic groups in the form of a carboxamide or carboxylic
ester.
Dibenzofurancarboxamides and 2-carboxamide-substituted
2 0 benzoxepines are reported to have 5HT3-antagonist and gastroprokinetic
activity in copending Application Serial Nos. 277,582; 277,611 and 412,768;
and U.S. Patents Nos. 4,857,517; 4,859,683 and 4,863,921; all of which are
assigned to the same assignee as the present application.
Summarv of the Invention
This invention relates to spiro[benzofuran-2(3H),1'-cycloalkane]-
carboxamides having ~HT3-antagonist, gastric prokinetic, and anti-emetic
activity and lack D2 receptor binding activity, and to therapeutic compositions
3 0 comprising said compounds. Preferred compounds of this invention are
described by general Formula I below.
.: - .~ . ,
,
,... . . ~ .
. , ;
-
. .. .
.. ' ; .
WO 91~16888 PCl/US91/02419
2~g ~ o ~ ~
: 5
: R
cH2)n
R3
: C=O
NH -R
Formula I
.
5 wherein
:, 'R1 is hydrogen, alkyl, halo, amino, acetylamino, dialkylamino or
carbamyl; ;
1 n R2 is hydrogen, alkyl, halo, trifluoromethyl, sulfamyl, mono- and di-
alkylsulfamyl, alkyl-sulfonyl, alkoxy, hydroxy, nitro, cyano, carboxy, carbalkoxy
~ or carbamyl;
; R3 is hydrogen or alkyl; R is 1-azabicyclo[2.2.2]oct-3-yl, 1-azabicyclo-
15 [2.2.2]oct-4-yl, 1-azabicyclo[3.3.1]non-4-yl, 9-methyl-9-azabicyclo[3.3.1]non-
3-yl, 9-methyl-7-oxa-9-azabicyclo[3.3.1]non-3-yl or 1-(p-fluorophenoxypropyl)-
3-methoxypiperidin-4-yl;
n is 1, 2, 3 or 4; and pharmaceutically acceptable salts thereof.
This invention relates also to pharmaceutical compositions including an
effective therapeutic amount of the aforementioned spiro[benzofurancyclo-
alkane]carboxamide compounds of Formula I and therapeutic methods for the
treatment of a patient suffering from gastrointestinal disorders and/or
25 psychochemical imbalances in the brain by administering said pharmaceutical
composition.
Detailed Description
3 0 As employed above and throughout the disclosure, the following, unless
otherwise indicated, shall be understood:
WO 91/16888 ~CI/US91/02419
2Q~011 6 `~
"Alkyl" means a saturated aliphatic hydrocarbon which may be either
straight- or branched-chained containing from about 1 to about 6 carbon
atoms.
"Lower alkyl" means an alkyl group as above, having 1 to about 4
carbon atoms.
o
"Carbamyl" means a group of the formula--c--NH2
1 0
"Alkoxy" means an alkyl-oxy group in which "alkyl" is as previously
described. Lower alkoxy groups are preferred. Exemplary groups include
methoxy, ethoxy, n-propoxy, i-propoxy and n-butoxy.
"Acyl" means an organic radical derived from an organic acid, a
carboxylic acid, by the removal of its acid hydroxyl group. Preferred acyl
groups are benzoyl and lower alkyl carboxylic acids groups such as acetyl and
propionyl.
2 0 The following numbering system is used to describe the compounds of
this invention:
5~(3)H'2)n
7 1 R3
2 5 The chemical nomenclature for the R groups defined above are
presented below.
[~
N 3-quinuclidine;
[~ 4-quinuclidine,
.. . . ~ ,
,
. ,~ - . , , "
WO 91/16888 2 ~ PCr/US91/02419
~ . :
N 4~ azablcyclo-[3.3~1]llonarle);
.
CH3
\~ 3-(9-methyiazabicyclo[3.3.1]nonane);
.
- NCH3
~ :.
0 7-(3-oxo-9-methylazabicyclo[3.3. 1 ]nonane); and
~N--~F
CH30 4-[3-methoxy-1-(-[4-fluorophenoxy]-
propyl)piperidine].
1 0
Certain of the compounds of the present invention may exist in enolic or
tutomeric forms, and all of these forms are considered to be included within thecope of this invention.
.
1 5 The compounds of this invention may be useful in the form of the free
base, in the form of salts and as a hydrate. All forms are within the scope of the -:
invention. Acid addition salts may be formed and are simply a more
convenient form for use; and in practice, use of the salt form inherently amounts
to use of the base form. The acids which can be used to prepare the acid
2 0 addition salts include preferably those which produce, when combined with the
free base, pharmaceutically acceptable salts, that is, salts whose anions are
non-toxic to the animal organism in pharmaceutical doses of the salts, so that
the beneficial cardiotonic properties inherent in the free base are not vitiated by
side effectts ascribable to the anions. Although pharmaceutically aceptable
2 5 salts of said basic compound are preferred, all acid addition salts are useful as
sources of the free base form even if the particular salt per se is desired only as
an intermediate product as, for example, when the salt is formed only for
purposes of purification and identification, or when it is used as an intermediate
in preparing a pharmaceutically acceptable salt by ion exchange procedures.
3 0 Pharmaceutically acceptable salts within the scope of the invention are those
.. . . ~ . . . ~ , .............................. . . .
. .
wo 91/16888 Pcr/~'s9l/02419
2~810l~ 8
derived from the following acids: mineral acids such as hydrochloric acid,
sulfuric acid, phosphoric acid and sulfamic acid; and organic acids such as
acetic acid, maleic acid, citrix acid, lactic acid, tartaric acid, malonic acid,methansefulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluene-
5 sulfonic acid, cyclohexylsulfamic acid, quinic acid, and the like. Thecorresponding acid addition salts comprise the following: hydrochloride,
sulfate, phosphate, sulfamate, acetate, citrate, lactate, tartarate, methane-
sulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate, cyclohexyl-
sulfamate and quinate, respectively.
1 0
The acid addition salts of the compounds of this invention are prepared
either by dissolving the free base in aqueous or aqueous-alcohol solution or
other suitable solvents containing the appropriate acid and isolating the salt by
evaporating the solution, or by reacting the free base and acid in an organic
1 5 solvent, in which case the salt separates directly or can be obtained by
concentration of the solution.
Preferred compounds of this invention include those of Formula I
wherein R1, R2, R3 and n are as described above and R is 1-azabicyclo-
20 [2.2.2]oct-3-yl, 1-azabicyclo[2.2.2]oct-4-yl and 1-azabicyclo[3.3.1]non-4-yl.
More preferred compounds of this invention include those of Formula I
wherein R is as described for the preferred compounds, R1 is hydrogen, amino,
loweralkylamino or dilower-alkylamino; R2 is hydrogen or halo; and R3 is
2 5 hydrogen.
Most preferred compounds of this invention include those of Formula I
wherein R is as described for the preferred compounds; R1 is hydrogen or
amino; R2 is hydrogen or halo; R3 is hydrogen; and n is 2 or 3, while n is 3 is
3 0 even further preferred.
The present compounds may be prepared by the following general
procedure:
. . , ~ . .
: :,
.
wo 91t16888 2 ~ ~101 i PCl'/US91/02419
R, R,
R2 ~ ,(CH2)n 1~ RNH2 , ~\(CH2)n
R3 R3
COOH C--NHR
Il ,
O
Condensation of a substituted spiro[benzofuran-2(3H),~'-cycloalkane]-7-
carboxylic acid, acid halides or ester with an amine of the formula R-NH2
5 results in the corresponding carboxamide.
, .
In general this reaction may be accomplished by adding ethyl
chloroformate to a solution of the acid in the presence of triethylamine at
reduced temperatures, such as 0C, followed by addition of the amine of
10 formula R-NH2. The reaction may also be accomplished by cornbining the acid
and amine in the presence of a dehydrating catalyst, such as a carbodiimide in
an appropriate solvent.
The starting materials, that is, the substituted spiro[benzofuran-2(3H),1'-
15 cycloalkane]-7-carboxylic acids, acid halides and esters are also novel. These
may be prepared from the corresponding substituted spiro[benzofuran-
2(3H),1'-cycloalkanesj by a carbonation procedure as shown in the following
reaction:
.
R R1 1) n-butyl llthium,
2 V~, ~ tetramethylethylene-
~¦ >~(CH2)n diamlne, hexane
~0 \~\ 2) CO2 ~dry)
R3R 3) H~, H20
R2
,(CH2)n
R3
2 0 COOH
.. . :- , - . ~ ,
" ' '' - ' ' . ' ' ' ' :
WO 91/16888 2 ~ 8 ~L O ~ 1 PCr/US91/02419
1 0
Formation of the acid halides and esters may be carried out in the usual
way.
. If the desired substituent or substituents (i.e. R1 and/or R2) are such as
5 to interfere with the carbonation reaction such as in the cases where the
desired substituent is amino or alkylamino, the substituent or substituents may
be protected with standard blocking groups, known in the art, followed by
deprotection by standard procedures at a point subsequent to the carbonation.
Where the desired substituent is an amino group, this may be converted to the
- 10 phthalimido group by heating with phthalic anhydride. Foilowing thecarbonation, the amino group may be regenerated by hydrazinolysis. This
sequence is shown in the following reaction scheme:
H2~n ~ C~
Hz ~ R~
COOH
1 5
When the desired substituent is alkylamino, protection may be
accomplished by acetylation, with subsequent deprotection by alkaline
hydrolysis as shown in the following scheme:
. , . . . . . ~ ~ , .
. - WO 91tl6888 2 ~ PCl-/US91/02419
1 1
NHR4
i
R2 ~ ~ acetic anhydride
( 2)n or acQtylchlorlde/Et3N
R3
O
4 ~N~ 3 NHR4
R2 1 1 ) carbonatlon ~
~\(CH2)n 2) OH, H20 ~ R3
R3 COOH
~ where R4 is an alkyl group.
; 5 As an alternative to carbonation of the appropriately substituted
spiro[benzofuran-2(3H),1'-cycloalkane], or a protected derivative thereof, the
desired substitution may be introduced subsequent to the carbonation and/or
- condensation withthe amine, R-NH2.
1 0 When the desired substitution is halo, such as bromo or chloro, the
carboxylic acid, acid halide or an ester thereof may be haiogenated using N-
bromosuccinimide or N-chloro-succinimide in dimethylformamide. If the ester
is used, this may be converted to ~he carboxylic acid by alkaline hydrolysis.
These reactions are shown in the following scheme:
J~H2)n C~ ~(CH~)n
COOH COOH
¦ dlazomethane
O H, H20
2)n [ ~N-X ~H2)n
COOCH3 COOCH~
where X is bromo or chloro.
, ... . ........ . ,.... ... ,.. ~ .... . . ., . , .. . -~ -
. . .. :- . .. :
. : . ~ . .... :. .. ~ .
wo 91/16888 2 ~ ~ ~ Q ~ i PCI,'US91/02419
12
When the desired substitution at the 5-position is sufamyl or mono- or di-
alkylsulfamyl, the sulfonyl chloride may be prepared from the ester using
chlorosulfonic acid, followed by formation of the sulfonamide using ammonia or
5 an alkyl amine.
¢~(CH~n CISO111 ~H,)n
COOCH3 COOCH3
o
R'NH--S
R'-NH2 O\~\;(CH2)n
COOCH3
where R' is hydrogen or alkyl.
1 0
Further, if the desired substitution at the 5-position is alkylsulfonyl, this
may be introduced using the alkylsulfonyl chloride in the presence of a catalystsuch as aluminum chloride.
o
R1 l l Rl .
~\ ~\ R4SO2CI ¦¦\~
~_0~\~( 2)n AICI ~ ,(CH2)n
3 I R3
1 5 COOCH3 COOCH3
where R4 is loweralkyl.
Depending on the chemistry involved, other desired end products
2 0 having various R2 substituents can be prepared at any appropriate stage of the
synthesis by using suitable reactions in order to convert one group to another,
Thus, for example, when R2 is chloro, bromo or iodo, this may be reacted with
.: WO 91/16888 ~ ~ g 1 0 ~ ~ PC'r/US91/02419
,
1 3
cuprous cyanide in quinoline at about 150C to produce those compounds
where R2 is cyano. This in turn may be converted to the acids, esters or
amides.
I
. 5 The halo group may also be reacted with trifluoromethyl-iodide and
copper powder at about 1 50C in DMF to obtain those compounds where R2 is
CF3. Halo may also be reacted with cuprous methanesulfinate in quinoline at
150C to obtain the methylsulfonyl substituent.
The R2 position of the spiro[benzofuran]ester may be nitrated in the
customary manner using HN03 and H2So4 at room temperature.
:
The spiro[benzofuran-2(3H),1'-cycloalkane] derivatives can be prepared
according to the following scheme:
1 5
~ R2~CHO R2~CHO
'`'bJI~ CH30CH2CI ~
OH 18 Crown-6 OCH20CH3
(CH2)n~p(0)3Br R2 1 --/\ CH
R3 ~ CH~ ( 2)n CH3COOH
CH3LI ~ R3 watQr
OCH20CH3
R~CH=~\(CHi)n CF~COOH ~ (CH~)n
Thus, the appropriately substituted salicylaldehyde derivative is treated
with chloromethylmethyl ether in the presence of 1 8-crown-6 in an appropriate
2 0 solvent such as acetonitrile to form the methoxymethoxybenzaldehyde
derivative. The benzylidene cycloalkane derivative is formed using a Wittig
reaction wherein the methoxymethoxy benzaldehyde derivative is reacted with
a cycloalkyltri-phenylphosphonium halide in the presence of methyllithium
The resulting methoxymethoxybenzylidene cycloalkane is deprotected (i.e. the
2 5 methoxymethyl group removed) by treatment with aqueous acetic acid. The
.- . . ~ . . - .
,. , , . . . - . . ~ . . , , - ~ . . ,
.:
- - .: : .
' . . ' ; ~ .
- . .
WO 91/16888 2 ~ 8 ~ PC~/US91/02419
1 4
cyclization to form the desired spiro[benzofuran-2(3H),1'-cycloalkane] is then
. accomplished using trifluoroacetic acid.
As mentioned above, the substituents R1 and R2 can be present on the
5 starting salicylaldehyde or may be introduced onto the molecule during a
subsequent step. The salicylaldehyde may also be substituted with groups
which may subsequently be converted to the desired substituents.
Therefore, it is also desirous that when substitution on the final
spiro[benzofuran-2(3H),1~-cycloalkane]-7-carboxamide is 4-amino, an
appropriate starting material may be 6-nitro-salicylaldehyde.
NO2 NO2
[~ CICH20CH3 [~CHO (cH2)n~p(0)3Br
~ OCH20CH3
~CI 1 =C~(CHZ)I1 CH,COOH ~CH=~ (CHz)n
NO2 NH2
TFA ~[~,(CH2)n P~2/H2 ~;;(CH2)n
3 R3
6-nitrosali.cylaldehyde is converted to 4-nitro[benzofùran-2(3H),1'-
cycloalkane] as described above and the nitro group is reduced under catalytic
hydrogenation conditions to give the 4-amino derivative which is subsequently
converted to the final product through the sequence described earlier.
2 0 The amino group may also be converted to mono- and di-alkylamino
groups at this point by treatment with lower alkyl halides or sulfates.
The amino group may also be diazotized to the diazonium flouride
which is then thermally decomposed to the flourine derivative compound. The
. ., . ~ ., .
. - . .. .
WO 91/16888 ~ PCI-/US91/02419
: .,
1 5
amine may also be diazotized and heated in an aqueous medium to form the
alcohol or heated in an alcohol to form the alkoxy compound.
Chlorosulfonation of the amine group may form the corresponding sulfamyl or
mono- and di-alkylsulfamyl groups.
The starting materials necessary for preparation of the compounds of the
present invention are available commercially, or are available through
standard chemical procedures known in the art.
Certain compounds of the present invention have one or more
asymmetric carbon atoms present in the amine portion of the carboxamide. It is
also possible to have an asymmetric center when R3 is alkyl. Thus, a given
compound may exist as two or more stereoisomers. When it is desired to
prepare a pure stereoisomer of a compound of the present invention, this may
be accomplished by using, as the starting amine, a stereochemically pure
amine. As an alternative, the final spiro[benzofuran-2(3H),1!-cycloalkane]-
- carboxamide derivative, if prepared as a mixture of stereoisomers, may be
resolved (i.e. the stereoisomers separated and purified) by standard
procedures known in the art. The resolution of the compounds is based on the
2 0 differences in the physical properties of diastereomers. Conversion of the
racemates into ~ mixture of diastereomers by attachment of an
enantiomerically pure moiety results in forms that are separable by fractional
crystallization, distillation or chromatography.
2 5 It is convenient to carry out condensation of the intermediate carboxylic
acids mentioned above with the amines of the formula H2N-Z using
stereospecific materials of each reactant. Accordingly, the acid may be
resolved into its stereoisomers prior to condensation with resolved amine.
3 0 We have found that the compounds of this invention have gastric
prokinetic and anti-emetic properties and lack D2-receptor binding activity. As
such they possess therapeutic value in the treatment of upper bowel motility
and gastro-esophageal reflux disorders. Further, the compounds of this
invention may be useful in the treatment of disorders related to impaired
3 5 gastrointestinal motility such as retarded gastric emptying, dyspepsia,
flatulence, esophageal reflux, peptic ulcer and emesis. The compounds of this
invention exhibit 5HT3 antagonism and are considered to be useful in the
- . .. - . . ~
-
- . .
.
WO 91/16888 2 ~ ~10 ~ ;~ PCI/US91/024~9
16
treatment of psychotic disorders such as schizophrenia and anxiety and in the
prophylaxis treatment of migraine and cluster headaches. We have further
found that these compounds are selective in that they have little or no
dopaminergic antagonist activity.
- 5
Various tests in animals can be carried out to show the ability of the
compounds of this invention to exhibit pharmacological responses that can be
correlated with activity in humans. These tests involve such factors as the
effect of the compounds of Formula I on gastric motility, emesis, selective
antagonism of 5HT3 receptors and their D2 dopamine receptor binding
properties.
:,'
It has been found that the compounds of this invention, when tested in
the above variety of situations, show a marked activity.
1 5
One such test is the "Rat Gastric Emptying. Amberlite Bead Method".
This test is carried out as follsws:
; . .
-. ~ The study is designed to assess the effects of a test agent on gastric
2 0 emptying of a solid meal in the rat. The procedure is a modification of those
- used in L.E. Borella and W. Lippmann (1980) Digestion 20: 26-49.
Procedure
2 5 Amberlite'~ beads are placed in a phenol red solution and allowed to
soak for several hours. Phenol red serves as an indicator, changing the beads
; from yellow to purple as their environment becomes more basic. After soaking,
the beads are rinsed with 0.1 NaOH to make them purple and then washed
; with deionized water to wash away the NaOH.
The beads are filtered several times through 1.18 and 1.4 mm sieves to
obtain beads with diameters in between these sizes. This is done using large
quantities of deionized water. The beads are stored in saline un~il ready to
use.
3~
. : . . i .. .
. ,, ~ .
. . , ~ .
- : . . . ~
.
.:
WO ~ 6888 ~ ~ 8 ~ PCI`/US91/02419
1 7
Male Sprague-Dawley rats are fasted 24 hours prior to the study with
water ad libitum. Rats are randomly divided in treatment groups with an N of 6
or7.
Test agents are prepared in 0.5% methylcellulose and administered to
the rats orally in a 10 ml/kg dose volume. Control rats receive 0.5%
methylcellulose, 10 ml/kg p.o. One hour after dosing, rats are given 60
Amberlite~ beads intragastrically. The beads are delivered via a 3 inch piece
of PE 205 tubing attached to a 16 gauge tubing adapter and syringe. A small
1 0 piece of PE 50 tubing is placed inside the tubing adapter to prevent the beads
- from being pulled back into the syringe. The beads are flushed into each rat's
stomach with 1 ml saline.
-.
Rats are sacrificed 30 minutes after receiving the beads and their
stomachs are removed. The number of beads remaining in each stomach is
counted after rinsing the beads with NaOH.
The number of beads remaining in each stomach is subtracted from 60
to obtain the number of beads emptied. The mean number of beads i S.E.M.
2 0 is determined for each treatment group. The percent change from control is
calculated as follows: -
' '
MearL5~ontrol GrQup - Mean J~st A~ent Group x 100
Mean Control Group
Statistical significance may be determined using a t-test for independent
samples with a probability of 0.05 or less considered to be significant.
In order to demonstrate the ability of the compounds of this invention as
3 0 anti-emetic agents the following test for "Cisplatin-lnduced Emesis in the
Ferret" may be used. This test is a modified version of a paper reported by A.P.Florezyk, J.E. Schurig and W.T. Brodner in Cancer Treatment Reports: Vol. 66,
No. 1. January 1982.
3 5 Cisplatin had been shown to cause emesis in the dog and cat. Florczyk,et al. have used the ferret to demonstrate the same effects.
- ~
WO91/16888 2Q~ PCI/US91/02419
1 8
- Procedure
',
Male castrated, Fitch ferrets, weighing between 1.0 and 1.5 kg have an
indwelling catheter placed in the jugular vein. After a 2-3 day recovery period,. 5 the experimental procedure is begun.
30 minutes prior to administration of cisplatin, ferrets are dosed with the
compound in 0.9% saline (i.v.) at a dose volume of 2.0 ml/kg.
1 0 Cisplatin is administered (i.v.) 30 minutes after the first dosing with tha
0.9% saline. Cisplatin, 10 mg/kg is administered in a dose volume of 2.0 ml/kg.
The time of cisplatin administration is taken as time zero. Ferrets are
observed for the duration of the experiment (4 hours). The elapsed time to the
1 5 first emetic episode is noted and recorded, as are the total number of periods of
emesis.
.
An emetic (vomiting) episode is characterized by agitated behavior,
such as pacing around the cage and rapid to and fro movements. Concurrent
- 2 0 with this behavior are several retching movements in a row, followed by a
single, large, retch which may or may not expulse gastric contents.
Immediately following the single large retch, the ferret relaxes. Single coughs
or retches are not counted as vomiting episodes.
D-2 Dop~min~or Bindin~ Assay
The D-2 dopamine receptor binding assay has been developed with
slight modifications using the method of lan Cresse, Robert Schneider and
Solomon H. Snyder, Europ. J. Pharmacol. 46: 377-381 (1977). Spiroperidol is
3 0 a butyrophenone neuroleptic whose affinity for dopamine receptors in brain
tissue is greater than that of any other known drug. It is a highly specific D-1dopamine (non-cyclase linked) receptor agent with K1 values of 0.1-0.~ for D-2
inhibition and 300 nM for D-1 inhibition.
3 5 Sodium ions are important regulators of dopamine receptors. The
affinity of the D-2 receptor is markedly enhanced by the presence of millimolar
concentrations of sodium chloride. The K2 in the absence and presence of
, . . . . .................. . ,. , . . . - .
-. . .
. - . . . : . . ~ .
.. ~ . ...
wo 91/16888 2 0 ~ ~ 01 t PC.r/US91/02419
; - !
1 9
120 mM sodium chloride is 1.2 and 0.086 nM respectively. Sodium chloride
(120 mM) is included in all assays as a standard condition.
The caudate nucleus (corpus striatum) is used as the receptor source
5 because it contains the highest density of dopamine receptors in the brain and periphery.
Proedure
.
Male Charles-River rats weighing 250-3009 are decapitated and their
brains removed, cooled on ice, and caudate dissècted immediately and frozen
on dry ice. Tissue can be stored indefinitely at -70C. For assay, caudate is
- homogenized in 30 ml of tris buffer (pH 7.7 at 25C) using polytron
homogenizer. The homogenate is centrifuged at 40,0009 (18,000-19,000 RPM
1 5 in SS-34 rotor) for 15 minutes. Pellet is resuspended in fresh buffer and
centrifuged again. The final pellet is resuspended in 150 volumes of assay
buffer.
: .
Specific 3H-spiroperidol binding is assayed in a total 2 ml reaction
2 0 volume consisting of 500 ~11 of caudate homogenate, 50 mM tris buffer (pH 7.4
- at 35C), 5 mM MgS04, 2 mM EDTA-2Na, 120 mM NaCI, 0.1% ascorbic acid,
0.4 nM 3H-spiroperidol and test compound or assay buffer. When
catecholamines are included in the assay, 10 ~,IM pargyline should be included
in the reaction mixture to inhibit monoamine oxidase. Samples are incubated
2 5 at 37C for 30 minutes followed by addition of 5 ml ice cold 50 mM TRIS (pH
7.7 at 25C) and filtration through GF/B glass fiber filters on a Brandel Receptor
Binding Filtration apparatus. Filters are washed twice with an additional 5 ml of
tris buffer each. Assay groups are performed in triplicate and 1 IlM d(+)
butaclamol is used to determine nonspecific binding. Filters are placed in vials3 0 containing 10 ml of Ecoscint phosphor, shaken for 30 minutes and dpm
determined by liquid scintillation spectrophotometry using a quench curve.
Proteins are determined by the method of Bradford, M. Anal. Biochem. 72, 248
(1976) using Bio-Rad's Coomassie blue G-250 dye reagent. Bovine gamma
globu!in supplied by BIO-RAD is used as the protein standard.
;;
: . ... .
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Wo 91/16888 2 ~ s3 ~ PCI/US91/1)2419
Bezold-Jarisçh Effect in Anaesthetized Rat~
`'
Male rats (260-290g) are anaesthetized with urethane 1.25 g/kg i.p., and
the trachea cannulated. The jugular vein is cannulated for intravenous (i.v.)
5 injection of drugs. Blood pressure is recorded from a cannula in the left carotid
artery and connected to a heparin/saline-filled pressure transducer.
Continuous heart rate measurements are taken from the blood pressure
recordings. The Bezold-Jarisch effect is evoked by rapid, bolus i.v. injections of
5HT and measurements are made of the fall in heart rate. In each rate,
1 0 consistent responses are first established with the minimum dose of 5HT thatevokes a clear fall in heart rate. Injections of ~HT are given every 12 minutes
and a dose-response curve for the test compound is established by injecting
increasing doses of compound ~ minutes before each injection of 5HT. The
. effect of the compound on the 5HT-evoked bradycardia is calculated as a
15 percent of the bradycardia evoked by ~HT before injection of compound.
.. .
In separate experiments to measure the duration of 5HT antagonism
caused by the compounds of this invention, a single dose of compound is
injected 5 minutes before 5HT, and the effects of 7 repeated challenges with
2 0 5HT are then monitored. The effects of the compound on the efferent vagal
limb of the Bezold-Jarisch reflex are checked by electrically stimulating the
peripheral end of a cut vagus nerve. Unipolar electrical stimulation is applied
every 5 minutes via a pair of silver electrodes, using 1 ms rectangular pulses in
5 strains with a maximally effective voltage (20 V at 10 Hz). Pulse frequency
2 5 may vary from ~-30 Hz and frequency response curves are constructed before
and 10 minutes after i.v. injection of a single dose of compound.
. The results of the above tests indicate that the compounds for this
invention exhibit a valuable balance between the peripheral and central action
3 0 of the nervous system and may be useful in the treatment of disorders related
to impaired gastro-intestinal motility such as gastric emptying, dyspepsia,
flatulence, esophogeal reflux and peptic ulcer and in the treatment of disordersof the central nervous system such as psychosis.
3 5 The compounds of the present invention can be administered to a
mammalian host in a variety of forms adapted to the chosen route of
administration, i.e., orally, or parenterally. Parenteral administration in this
:' ' .. ''' . . ' ~ :,
.
WO 91/16888 PCr/l,'S91/02419
29~10~ ~
~ 21
, ,
respect includes administration by the following routes: intravenous,
:' intramuscular, subcutaneous, intraocular, intrasynovial, transepithelially
including transdermal, opthalmic, sublingual and buccal; topically including
opthalmic, dermal, ocular, rectal and nasal inhalation via insufflation and
aerosol and rectal systemic.
,.
The active compound may be orally administered, for example, with an
inert diluent or with an assimilable edible carrier, or it may be enclosed in hard
or soft shell gelatin capsules, or it may be compressed into tablets, or it may be
1 0 incorporated directly with the food of the diet. For oral therapeutic
administration, the active compound may be incorporated with excipient and
used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs,
suspensions, syrups, wafers, and the like. Such compositions and
~ preparations should contain at least 0.1% of active compound. The
y 1 5 percentage of the compositions and preparations may, of course, be varied
and may conveniently be between about 2 to about 6% of the weight of the
unit. The amount of active compound in such therapeutically useful
compositions is such that a suitable dosage will be obtained. Preferred
compositions or preparations according to the present invention ~re prepared
2 0 so that an oral dosage unit form contains between about 50 and 300 mg of
active compound.
The tablets, troches, pills, capsules and the like may also contain the
foilowing: A binder such as gum tragacanth, acacia, corn starch or gelatin;
2 5 excipients such as dicalcium phosphate; a disintegrating agent such as corn
starch potato starch, Iyginic acid and the like; a lubricant such as magnesium
stearate; and a sweetening agent such as sucrose, lactose or saccharin may
be added or a flavoring agent such as peppermint, oil of wintergreen, or cherry
flavoring. When the dosage unit form is a capsule, it may contain, in addition to
3 0 materials of the above type, a liquid carrier. Various other materials may be
present as coating or to othen,Nise modify the physical form of the dosage unit.For instance, tablets, pills or capsules may be coated with shellac, sugar or
both. A syrup or elixir may contain the active compound using sucrose as a
sweetening agent, methyl and propylparabens as preservatives, a dye and
3 5 flavoring such as cherry or orange flavor. Of course, any material used in
preparing any dosage unit form should be pharmaceutically pure and
substantially non-toxic in the amounts employed. In addition, the active
. . . : .
,
WO 91/16888 2 ~ . i P~/IJS91/02419
22
. .
compound may be incorporated into sustained-release preparations and
formulations.
The active compound may also be administered parenterally or
5 intraperitoneally. Solutions of the active compound as a free base or
pharmacologically acceptable salt can be prepared in water suitably mixed
with a surfactant such as hydroxy-propylcellulose. Dispersion can also be
prepared in glycerol, liquid polyethylene glycols, and mixtures thereof and in
oils. Under ordinary conditions of storage and use, these preparations contain
- 1 0 a preservative to prevent the growth of microorganisms.
. .
The pharmaceutical forms suitable for injectable use include sterile
aqueous solutions or dispersions and sterile powders for the extemporaneous
preparation of sterile injectable solutions or dispersions. In all cases the form
1 5 must be sterile and must be fluid to the extent that easy syringability exists. It
must be stable under the conditions of manufacture and storage and must be
preserved against the contaminating action of microorganisms such as
bacteria and fungi. The carrier can be a solvent or dispersion medium
containing, for example, water, ethanol, polyol (for example, glycerol,
propylene glycol, and liquid polyethylene glycol, and the like), suitable
mixtures theresf, and vegetable oils. The proper fluidity can be maintained, forexamp!e, by the use of a coating such as lecithin, by the maintenance of the
required particle size in the case of dispersion and by the use of surfactants.
The prevention of the action of microorganisms can be brought about by
2 5 various antibacterial and antifungal agents, for example, parabens,
chlorobutanol, phenol, sorbic acid, thimersal, and the like. In many cases, it
will be preferable to include isotonic agents, for example, sugars or sodium
chloride. Prolonged absorption of the injectable compositions of agent
delaying absorption, for example, aluminum monostearate and gelatin.
3~
Sterile injectable solutions are prepared by incorporating the active
compound in the required amount in the appropriate solvent with various of the
other ingredients enumerated above, as required, followed by filtered
sterilization. Generally, dispersions are prepared by incorporating the various
3 5 sterilized active ingredient into a sterile vehicle which contains the basic - -
dispersion medium and the required other ingredients from those enumerated
above. In the case of sterile powders for the preparation of sterile injectable
: - , ' ' ~',. ', ., -:,
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- W O 91/16888 ~ ~ 8 ~ 0 ~ i P ~ /US91/02419
2 3
' .
solutions, the preferred methods of preparation are vacuum drying and the
freeze drying technique which yield a powder of the active ingredient plus any
; additional desired ingredient from previously sterile-filtered solution thereof.
The therapeutic compounds of this invention may be administered to a
mammal alone or in combination with pharmaceutically acceptable carriers, as
noted above, the proportion of which is determined by the solubility and
:; chemical nature of the compound, chosen route of administration and standard
pharmaceutical practice.
1 0
. The physician will determine the dosage of the present therapeutic
agents which will be most suitable for prophylaxis or treatment and will vary
with the form of administration and the particular compound chosen, and also,
it will vary with the particular patient under treatment. He will generally wish to
initiate ~reatment with small dosages by small increments until the optimum
effect under the circumstances is reached. The therapeutic dosage will
generally be from 0.1 to 20 mg or from about 0.01 mg to about ~0 mglkg of
body weight per day and higher although it may be administered in several
different dosa~e units from once to several times a day. Higher dosages are
2 0 required for oral administration.
:,
The compounds of this invention may be prepared by the following
representative examples.
.
Example 1
N-[1 -azabicyclo[2.2.2]oct-3-yl]-5-chlorospiro-
' lbenzofuran-2(3H).1'-cyclohexane~-7-carboxamide
A. ~Me~hox~methoxybenzaldçhvde
3 0 .1 25g of salicylaldehyde is dissolved in 1250 ml of anhydrous
acetonitrile and the solution cooled in an ice bath. 11 5g of potassium-t-
butoxide is added and the mixture stirred for 15 minutes. 28g of 1 8-crown-6 is
added and this stirred for 30 minutes. 115 ml of chloromethylmethyl ether is
then added over a period of 5 minutes and the mixture stirred in the ice bath for
3 5 5 minutes, then at ambient temperatures for 1.5 hours. The mixture is filtered
and the clear filtrate evaporated in vacuo. The oil residue is dissolved in 1 L of
ether and this solution washed with water, 5% sodium hydroxide solution,
: -
.
" ' ~ . '
WO 91/16888 ~ PCr/US91/02419
; 24
. .
water, brine th~n dried over sodium sulfate. This was filtered and evaporated
`! in vacuo to 1539 of 2-methoxy-methoxybenzaldehyde which is used, without
further treatment for the next step.
... .
B. 2-Methoxymethoxvbenzvlidene çvclohexane
1309 of cyclohexyltriphenylphosphonium bromide is suspended in 1.3L
of anhydrous tetrahydrofuran and cooled to 5C in an ice bath. 218 ml of 1.4 M
methyllithium in ether is added over a period of 10 minutes. The mixture is
stirred for 10 n~inutes and 50.8g of 2-methoxymethoxy-benzaldehyde in 100 ml
1 0 of tetrahydrofuran is added over 10 minutes. The mixture is stirred at ice bath
~emperature for 5 minutes, then at room temperature for 1.5 hours. 200 ml of
water is added, the mixture stirred for 15 minutes, then evaporated in vaçuo.
The residue is taken up in 500 ml water/1 L ether. This is filtered, the layers
separated and the aqueous extracted with ether. The combined ether solution
is washed with water, brine, dried over sodium sulfate, then filtered and
evaporated in vacuo to give the crude product which is purified by flash
chromatography in petroleum ether/methylene chloride (1:1) to give
2-methoxymethoxybenzylidene cyclohexane.
C. 2-Hvdroxvbenzyldene cyçlohexane
34.2g of 2-methoxymethoxybenzylidene cyclohexane is suspended in
1 .5L of 2 Normal acetic acid in water and this stirred at reflux for 44 hours. The
mixture is extracted with ether and the ether solution washed with water, 10%
aqueous sodium bicarbonate solution, water, brine, then dried over sodium
2 5 sulfate. The ether solution is filtered, and evaporated in vacuo to give
2-hydroxybenzylidene cyclohexane which is used, without further treatment, for
the next step.
. ., . .-, "
D. Spiro[benzofuran-2(3H~ yclohexane]
3 0 24.9g of 2-hydroxybenzylidene cyclohexane is dissolved in 250 ml of
trifluoroacetic acid and the solution stirred at room temperature for 1.~ hours.The solution is evaporated in vacuo and the residue dissolved in 250 ml of
ether. The ether solution is washed with water, saturated sodium bicarbonate
solution, water, brine and dried over sodium sulfate. This is filtered,
3 ~ evaporated to a crude product which is purified by flash chromatography in
hexane/methylene chloride (2:1) to give 19.6g spiro[benzofuran-2(3H),1'-
cyclohexane] .
.. . . . .
.
-,, . . .. ,: ~:: - ... . , : , . -
wo 91/16888 ~ ~ 3 ~ Q ~ 1 PCl/US91/02419
..
' ' .
E. Spiro[benzofuran-2(3H).1'-cyclohexane]-7-carboxylic acid
37.3 ml of 2.5M n-butyl lithium in hexane is added to 150 ml of hexane
and 14.1 ml of tetramethylethylenediamine is added over a period of 1 minute.
The mixture is stirred at room temperature for 30 minutes and 13.59 of
spiro[benzofuran-2(3H),1'-cyclohexane] in 20 ml of hexane is added over 1
minute and the solution heated at reflux for 5.5 hours. The mixture is cooled inan ice bath and dry carbon dioxide gas is bubbled in for 45 minutes. The
mixture is diluted with 150 ml of ether and 200 ml of water, then acidified with1 0 6N hydrochloric acid. The layers are separated and the aqueous layer
extracted with ether. The combined organic solution is washed with water,
then extracted with 2 x 250 ml of 5% sodium hydroxide solution. With cooling,
the basic solution is acidified with 6N HCI and the resulting oil extracted intoether. The ether solution is washed with water, brine, dried over sodium
1 5 sulfate, then evaporated in vacuo to give the cnude product which is purified by
crystallization from ethyl acetate to give spiro[benzofuran-2(3H),1'-
cyclohexane]-7-carboxylic acid.
F. Methyl spiro[benzofuran-2(3H~.1'-cyclohexane]-7-carboxylate
To a solution of 2.869 of spiro[benzofuran-2(3H),1'-cyclohexane]-7-
carboxylic acid in 200 ml of ether is added a solution of approximately 39 of
diazomethane in 200 ml of ether in large portions over a period of 5 minutes.
The solution is stirred at room temperature for 2.5 hours. 6 ml of glacial acetic
acid is carefully added and the mixture stirred for 5 minutes. The solution is
2 5 washed with 200 ml of saturated sodium bicarbonate solution, water, brine,
and dried over sodium sulfate. The solution is filtered, evaporated to give
2.96g of methyl spiro[benzofuran-2(3H),1'-cyclohexane]-7-carboxylate. This is
used without further treatment, for the next step.
3 0 G. Methvl-5-chlorospiro[benzofuran-2(3H!.1 '-cvclohexanel-7-carboxvlate
2.59g of methyl spiro[benzofuran-2(3H),1'-cyclohexane]-7-carboxylate
and 2.11g of freshly recrystallized N-chloro-succinimide are dissolved together
in 13 ml of dimethyl-formamide and the solution stirred at room temperature for
four days. The solution is diluted with 40 ml of water and extracted with 2 x 503 5 ml of ether. The ether solution is washed with 3 x 50 ml of water, brine, dried
over sodium sulfate. The solution is filtered and evaporated to a white solid,
methyl-5-chlorospiro[benzofuran-2(3H),1 '-cyclohexane]-7-carboxylate.
;
WO91/16888 2~8~ O :~ PCI/US91/02419
.. ~. .. .
26
.. ,. . ~ ~ .
H. 4-Chlorospiro[benzofuran-2(3H!.1'-cyclohexane]-7-carboxylic acid
2.669 methyl-5-chlorospiro[benzofuran-2(3H),1'-cyclohexane]-7-
carboxylate is refluxed in a mixture of 100 ml methanol and 2~ ml 10% (w/w)
5 aqueous sodium hydroxide for 2 hours. The reaction mixture is evaporated in
vacuo to remove most of the methanol, then diluted with 100 ml of ether and
100 ml of 5% hydrochloric acid. The layers are separated and the aqueous
layer extracted with ether. The combined ether solution is washed with water,
brine, and dried over sodium sulfate. This solution is filtered and evaporated in
10 vacuo to give 2.40g of 5-chlorospiro[benzofuran-2(3H),1'-cyclohexane]-7-
.. carboxylic acid.
. , .
1. N-[1-a~zabicvclo[2.2.2]oct-3-vl]-5-chlorospiro-~benzofuran-2(3H),1'-
~yclohexane]-7-carboxamide
0.50g 5-chlorospiro[benzofuran-2(3H),1'-cyclohexane]-7-carboxylic acid
is dissolved in 2.5 ml of chloroform and 0.39g of triethylamine. The solution is
cooled in an ice bath, 0.22 ml of ethyl chloroformate is added over a period of 5
; minutes and the solution is stirred at 0C for 1.5 hours. 2.5 ml of chloroform is
added followed by a solution of 1.86g 3-aminoquinuclidine hydrochloride in 6
2 0 ml of 50% (w/w) aqueous potassium carbonate solution and 3 ml of water
which had been cooled to 0C. This mixture is stirred at 0C for 30 minutes,
then at room temperature for 18 hours. The mixture is partitioned between 50
ml of ethyl acetate and 50 ml of water. The ethyl acetate layer is washed with
. water, brine, dried over sodium sulfate, filtered and evaporated to the crude
- 2 5 product which is crystallized from ethyl acetate to give N-[1 -azabicyclo[2.2.2]-
oct-3-yl]-5-chlorospiro[benzofuran-2(3H),1'-cyclohexane]-7-carboxamide; m.p.
1 60-1 62C.
Example 2
3 0 When the amines of Table I below are substituted for 3-amino-
quinuclidine in Example 11, then the corresponding compounds of Table ll are
prepared.
- wo sl/l6g88 2 0 ~ L Pcl/us9lto~4ls
27
- Table I
NH2
a. 4-amino-1-azabicyclo[2.2.21octane [~ ~
NH2~
5 b. 4-amino-1-azabicyclo[3.3.1]nonane ~N
,:
CH3
" NH2 ~
c. 3-amino-9-methyl-9-azabicyclo[3.3.1 ]nonane ~
NCH3
' NH2~
d. 3-amino-7-oxa-9-methyl-9-æabicyclo[3.3.1 ]nonane O .. 10
e. 1-(p-fluorophenoxypropyl)-3-methoxy-4-aminopiperidine
,, .
NH2~N ~F
CH30
, . .
Table ll
a. N-[1-azabicyclo[2.2.2]oct-4-yl]-5-chlorospiro[benzofuran-2(3H),1'-
cyclohexane]-7-carboxamide
20 b. N-[1-azabicyclo[3.3.1]non-4-yl]-5-chlorospiro[benzofuran-2(3H),1'-
cyclohexane]-7-carboxamide
c. N-[9-methyl-9-azabicyclo[3.3.1 ]non-3-yl]-5-chlorospiro[benzo~uran-
2(3H) ,1 '-cyclohexane]-7-carboxamide
d. N-[7-oxa-9-methyl-9-azabicyclo[3.3.1 ]non-3-yl]-5-chlorospiro-
[benzofuran-2(3H), 1 '-cyclohexane]-7-carboxamide
,~
WO 91/16888 2 ~ PCl/US91/02419
~., .
28
'
e. N-[1-(p-fluorophenoxypropyl~-3-methoxy-piperidin-4-yl]-5-chlorospiro-
[benzofuran-2(3H),1'-cyclohexane]-7-carboxarnide
Examp!~-
N-[1-azabicyclo[2.2.2]oct-3(S)-yl]-5-chlorospiro-
~benzofuran-2(3H).1'-cvçlohexane]-7-carboxamide
.
N-[1 -azabicyclo[2.2.2]oct-3(R)-yl]-5-chlorospiro-
~benzofuran-2(3H! .1 '-cyclohexane]-7-carboxamide
1 0
When (S-)-3-aminoquinuclidine is substituted for 3-aminoquinuclidine in
Example 11, then N-[1-azabicyclo[2.2.2]oct-3(S)-yl]-5-chlorospiro[benzofuran-
2(3H),1'-cyclohexane]-7-carboxamide (m.p. 143-146C) is obtained.
1 5 In a similar manner when (R+)-3-aminoquinuclidine is used the product
obtained is N-[1-azabicyclo[2.2.2]oct-3(R)-yl]-5-chlorospiro[benzofuran-
2(3H),1'-cyclohexane-7-carboxamide (m.p. 149-155C).
Example 4
2 0 When the triphenylphosphonium derivatives of Table lll below are
substituted for cyclohexyltriphenylphosphonium bromide in Example 1 B, then
the corresponding compounds of Table IV are prepared.
Table lll
a. Cyclobutyltriphenylphosphonium bromide
b. Cyclopentyltriphenylphosphonium bromide
c. Cycloheptyltriphenylphosphonium bromide
d. 3-Methylcyclohexyltriphenylphosphonium bromide
Table IV
a. 2-Methoxymethoxybenzylidenecyclobutane
b. 2-Methoxymethoxybenzylidenecyclopentane :
- 3 5 c. 2-Methoxymethoxybenzylidenecycloheptane
d. 2-Methoxymethoxybenzylidene-3'-methylcyclohexane
.. - . ,. ~ . . ..
- WO 91/16888 2 ~ PCl-/US91/02419
29
Example 5
When the compounds of Table IV, above are substituted for
2-methoxymethoxybenzylidene cyclohexane in Example 1C, and the
: corresponding products treated sequentially as in Examples 1 D through 11,
5 then the corresponding compounds of Table V are prepared.
,
Tabie V
a. N-[1-azabicyclo[2.2.2]oct-3-yl]-5-chlorospiro[benzofuran-2(3H),1'-
1 0 cyclobutane]-7-carboxamide
b. N-[1-azabicyclo[2.2.2]oct-3-yl]-5-chlorospiro[benzofuran-2(3H),1'-
cyclopentane]-7-carboxamide
. .
: 15 c. N-[1-azabicyclo[2.2.2]oct-3-yl]-5-chlorospiro[benzofuran-2(3H),1'-
cycloheptane]-7-carboxamide
.
d. N-[1-azabicyclo~2.2.2]oct-3-yl]-5-chlorospiro[benzofuran-2(3H,1'3'-
methylcycloheptane]-7-carboxamide
: 20
Example 6
4-Amino-N-[1 -azabicyclo[2.2.2]oct-3-yl]-
.~ spiro[benzofuran-2(3H).1'-cyclohexane]-7-carbQxamide
2 5 A. 2-methoxvmethoxy-6-nitrobenzaldehvde
When 6-nitrosalicylaldehyde is substituted for salicylaldehyde in
Example 1A, then 2-methoxymethoxy-6-nitrobenzaldehyde is prepared.
B. (2-MethQxymeLhQxy-6-nitrobenzylidene)cyclohexane
- 3 0 When 2-methoxymethoxy-6-nitrobenzaldehyde is substituted for
2-methoxymethoxybenzaldehyde in Example 1 B, then (2-methoxymethoxy-6-
nitrobenzylidene)cyclohexane is prepared.
C. (2-hydrQxv-6-nitrobenzvlidene)cvclohexane
3 5 When (2-methoxymethoxy-6-nitrobenzylidene)cyclohexane is
substituted for 2-methoxymethoxybenzylidenecyclohexane in Example 1C,
then (2-hydroxy-6-nitrobenzylidene)cyclohexane is prepared.
:....................................... .
. , .~ ~.
: . ;
. ~
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:
WO 9~t16888 ~ ~ 8 ~ ~ ~ L PCI/US91/02419
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D. 4-Nitro$pi_o~nzofuran-2(3H). 1 '-cyclohexane~ -
When (2-hydroxy-6-nitrobenzylidene)cyclohexane is substituted for
2-hydroxybenzylidenecyclohexane in Example 1D, then 4-nitrospiro-
5 [benzofuran-2(3H),1'-cyclohexane] is prepared.
.
E. 4-AminQ~Q[benzofuran-2(3H!.1'-çyclohexane]
0.50g of 4-nitrospiro[benzofuran-2(3H),1'-cyclohexane] is dissolved in
10 ml of ethyl acetate and 0.25g of platinum oxide is added. The mixture is
1 0 shaken under 45 psi of hydrogen for 24 hours, filtered, evaporated in vacuo
and the crude product purified by flash chromatography to give 4-aminospiro-
[benzofuran-2(3H), 1 '-cyclohexane].
.: .
F. 4-phthalimidospiro~benzofuran-2(3H). 1 '-cyçlohexane]
2.029 of 4-aminospiro[benzofuran-2(3H),1'-cyclohexane] and 1.48g of
phthalic anhydride are heated together at 1 60C for 3 hours, cooled and the
resulting solid crystallized from ethanol to give 4-phthalimido[benzofuran-
2(3H), 1 '-cyclohexane].
- 20 G. 4-Phthalimidospirolbenzofuran-2(3H!.1'-cyclohexane]-7-carboxvlic acid
When 4-phthaiimidospirolbenzofuran-2(3H),1'-cyclohexane] is
substituted for spiro[benzofuran-2(3H),1'-cyclohexane] in Example 1 E, then
; 4-phthalimidospiro[benzofuran-2(3H),1'-cyclohexane]-7-carboxylic acid is
obtained.
H. 4-aminosDiro[benzofuran-2(3H).1'-cvclohexane]-7-carboxylic acid
2.00g of 4-phthalimidospiro[benzofuran-2(3H),1'-cyclohexane]-7-
carboxylic acid and 0.60 ml of 98% hydrazine are heated together at reflux in
40 ml of absolute ethanol for 4 hours. The reaction mixture is allowed to cool,
3 0 filtered and the filtrate evaporated in vacuo. The residue is stirred with 5%
sodium hydroxide solution, filtered, and the filtrate adjusted to pH 7 with 1 N
hydrochloric acid,- and the product extracted into methylene chloride which is
washed, dried and evaporated. The crude product is purified by flash
chromatography to give 4-aminospiro~benzofuran-2(3H),1'-cyclohexane]-7-
3 5 carboxylic acid.
. : . .. . , ~ . ~ . -
.. . . - ~: - . . ~
. . . . ..
. ~ . . . .. . -
: . .- . . ., . , , . . ~. : , ..
W O 91~16888 ~ PC~r/US91/02419
3 1
4-Amino-N-~1-azabicvclo[2.2.2]oct-3-yllspiro-[benzofuran-2(3H) 1'-
cvclohexane]-7-carboxamide
To a solution of 1.43g of 4-aminospiro[benzofuran-2(3H),1'-
cyclohexane]-7-carboxylic acid in 8 ml of piridine at 0C is added 1.4g of N,N'-dicyclohexylcarbodiimide in one portion. The mixture is stirred at 0C for 1
hour and then 1.239 of 3-aminoquinuclidine dihydrochloride is added. The
mixture is then allowed to warm and stirred at room temperature overnight. 8
ml of 1N sodium hydroxide solution is added, the mixture stirred for 30 minutes,then filtered. The [residue or filtrate] is taken up in methylene chloride, washed
1 0 with water, dried over magnesium sulfate and concentrated to dryness to give
4-amino-N-[1 -azabicyclo[2.2.2]oct-3-yl]spiro[benzofuran-2(3H),1 '-
cyclohexane]-7-carboxamide.
:
Example 7
1 5 4-Amino-N-[1 -æabicyclo[2.2.2]oct-3-yl]-5-
çhlor~spiro[benzofuran-?~H!. 1 '-cyclohexane]-7-carboxamide
A. 5-Chloro-4-phthalimidospirQ[benzofuran-2(3H).1'-cyclohexane~-7-
carboxylic acid
When 4-phthalimidospiro[benzofuran-2(3H),1'-cyclohexane]-7-
carboxylic acid is substituted for methyl-5-chlorospiro[benzofuran-2(3H),1'-
cyclohexane]-7-carboxylate in Example 1G, then 5-chloro-4-phthalimidospiro-
lbenzofuran-2(3H),1'-cyclohexane3-7-carboxylic acid is prepared.
2 5 B. 4-Amino-N-[1 -azabicyclo[2.2.2]oct-3-vl3-5-chlorospiro[benzofuran-
2(3H).1'-cyclohexane]-7-carboxamide
When 5-chloro-4-phthalimidospiro[benzofuran-2(3H),1'-cyclohexane]-7-
carboxylic acid is substituted for 4-phthal-imidospiro[benzofuran-2(3H),1'-
cyclohexane~-7-carboxylic acid in Example 6H, and the corresponding product
3 0 treated as in Example 61, then 4-amino-N-[1 -azabicyclo[2.2.2]oct-3-yl]-5-
chlorospiro[benzofuran-2(3H),1'-cyclohexane]-7-carboxamide is obtained.
.
- . " , ~ . ~ . :
.. , -
- . ' ~ . .: ~ ' . . '.
w~ 91/16888 2 ~ L ~ PCr/US91/02419_
32
` .
Examp!e 8
N-[1 -Azabicyclo[2.2 .2]oct-3-yl]-5-bromospiro-
[benzofuran-2(3H!.1'-çvçlohexanel-7-çarboxamide
5 When N-bromosuccinimide is substituted for N-chlorosuccinimide in
Example 1 G, and the corresponding product treated as in Examples 1 H and 11,
then N-[1-azabicyclo[2.2.2]oct-3-yl]-5-bromospiro[benzofuran-2(3H),1'-cyclo-
hexane]-7-carboxamide is prepared.
, 1 0
. . ,
; '
., .
. . . . .
. ;
.
