U.S. patent application number 15/360393 was filed with the patent office on 2017-03-16 for nicotinic receptor non-competitive antagonists.
The applicant listed for this patent is Catalyst Biosciences, Inc.. Invention is credited to Srinivasa Rao Akireddy, Balwinder Singh Bhatti, Ronald Joseph Heemstra, Matt S. Melvin, Jason Speake, Yunde Xiao, Daniel Yohannes.
Application Number | 20170071878 15/360393 |
Document ID | / |
Family ID | 44462072 |
Filed Date | 2017-03-16 |
United States Patent
Application |
20170071878 |
Kind Code |
A1 |
Akireddy; Srinivasa Rao ; et
al. |
March 16, 2017 |
NICOTINIC RECEPTOR NON-COMPETITIVE ANTAGONISTS
Abstract
The present invention relates to compounds that modulate
nicotinic receptors as non-competitive antagonists, methods for
their synthesis, methods for use, and their pharmaceutical
compositions.
Inventors: |
Akireddy; Srinivasa Rao;
(Winston-Salem, NC) ; Bhatti; Balwinder Singh;
(Winston-Salem, NC) ; Heemstra; Ronald Joseph;
(Winston-Salem, NC) ; Speake; Jason;
(Winston-Salem, NC) ; Yohannes; Daniel;
(Winston-Salem, NC) ; Melvin; Matt S.;
(Winston-Salem, NC) ; Xiao; Yunde; (Clemmons,
NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Catalyst Biosciences, Inc. |
South San Francisco |
CA |
US |
|
|
Family ID: |
44462072 |
Appl. No.: |
15/360393 |
Filed: |
November 23, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14837023 |
Aug 27, 2015 |
9532974 |
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15360393 |
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14320782 |
Jul 1, 2014 |
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14837023 |
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13699757 |
Mar 22, 2013 |
8809397 |
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PCT/US2011/037630 |
May 24, 2011 |
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14320782 |
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61375606 |
Aug 20, 2010 |
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61349027 |
May 27, 2010 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61P 25/26 20180101;
A61K 31/13 20130101; C07C 211/38 20130101; C07C 211/41 20130101;
C07D 295/033 20130101; A61P 9/12 20180101; A61K 31/397 20130101;
A61P 13/10 20180101; A61K 31/40 20130101; A61P 25/24 20180101; A61P
1/00 20180101; A61P 25/34 20180101; A61P 25/30 20180101; C07D
205/04 20130101 |
International
Class: |
A61K 31/13 20060101
A61K031/13 |
Claims
1. A method for the treatment of nicotine addiction or smoking
cessation comprising the administration of a compound of Formula I:
##STR00024## wherein each of R.sup.1 and R.sup.2 individually is H,
C.sub.1-6 alkyl, or aryl-substituted C.sub.1-6 alkyl, or R.sup.1
and R.sup.2 combine with the nitrogen atom to which they are
attached to form a 3- to 8-membered ring, which ring may be
optionally substituted with C.sub.1-6 alkyl, aryl, C.sub.1-6
alkoxy, or aryloxy substituents; R.sup.3 is H, C.sub.1-6 alkyl, or
C.sub.1-6 alkoxy-substituted C.sub.1-6 alkyl; each of R.sup.4,
R.sup.5, R.sup.6, and R.sup.7 individually is H, C.sub.1-6 alkyl,
or C.sub.1-6 alkoxy; L.sup.1 is a linker species selected from the
group consisting of CR.sup.8R.sup.9,
CR.sup.8R.sup.9CR.sup.10R.sup.11, and O; L.sup.2 is a linker
species selected from the group consisting of CH.sub.2,
CH.sub.2CH.sub.2, CH.sub.2CH.sub.2CH.sub.2, and
CH.sub.2CH.sub.2CH.sub.2CH.sub.2; each of R.sup.8, R.sup.9,
R.sup.10, and R.sup.11 individually is hydrogen or C.sub.1-6 alkyl;
and the dashed line indicates an optional double bond; or a
pharmaceutically acceptable salt thereof.
2. The method of claim 1, wherein the disease or condition is
IBS-D, GAB, depression, major depressive disorder, or
hypertension.
3. A method for the treatment of nicotine addiction or smoking
cessation comprising the administration of a compound ##STR00025##
or a pharmaceutically acceptable salt thereof.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 14/320,782 filed Jul. 1, 2014, which is a continuation of U.S.
application Ser. No. 13/699,757, filed Mar. 22, 2013, now U.S. Pat.
No. 8,809,397, issued on Aug. 19, 2014, which is a .sctn.371 filing
of PCT Application No. PCT/US2011/037630, with an International
Filing Date of May 24, 2011, which claims priority to U.S.
Provisional Patent Application Ser. No. 61/349,027, filed May 27,
2010 and U.S. Provisional Patent Application Ser. No. 61/375,606
filed Aug. 20, 2010; each of which is herein incorporated by
reference in its entirety
FIELD OF THE INVENTION
[0002] The present invention relates to compounds that modulate
nicotinic receptors as non-competitive modulators (e.g.,
non-competitive antagonists), methods for their synthesis, methods
for use, and their pharmaceutical compositions.
BACKGROUND OF THE INVENTION
[0003] Nicotinic receptors are targets for a great number of
exogenous and endogenous compounds that allosterically modulate
their function. See, Arias, H, R., Binding sites for exogenous and
endogenous non-competitive inhibitors of the nicotinic
acetylcholine receptor. Biochimica et Biophysica Acta--Reviews on
Biomembranes 1376: 173-220 (1998) and Arias, H. R., Bhumireddy, P.,
Anesthetics as chemical tools to study the structure and function
of nicotinic acetylcholine receptors, Current Protein & Peptide
Science 6: 451-472 (2005). The function of nicotinic receptors can
be decreased or blocked by structurally different compounds called
non-competitive modulators, including non-competitive antagonists
(reviewed by Arias, H. R., Bhumireddy, P., Bouzat, C., Molecular
mechanisms and binding site locations for noncompetitive
antagonists of nicotinic acetylcholine receptors. The International
Journal of Biochemistry & Cell Biology 38: 1254-1276
(2006)).
[0004] Non-competitive modulators comprise a wide range of
structurally different compounds that inhibit receptor function by
acting at a site or sites different from the orthosteric binding
site. Receptor modulation has proved to be highly complex. The
mechanisms of action and binding affinities of non-competitive
modulators differ among nicotinic receptor subtypes (Arias et al.,
2006). Non-competitive modulators may act by at least two different
mechanisms: an allosteric and/or a steric mechanism.
[0005] An allosteric antagonist mechanism involves the binding of a
non-competitive antagonist to the receptor and stabilization of a
non-conducting conformational state, namely, a resting or
desensitized state, and/or an increase in the receptor
desensitization rate.
[0006] In contrast, a straightforward representation of a steric
mechanism is that an antagonist molecule physically blocks the ion
channel. Such antagonists may be termed non-competitive channel
modulators (NCMs). Some inhibit the receptors by binding within the
pore when the receptor is in the open state, thereby physically
blocking ion permeation. While some act only as pure open-channel
blockers, others block both open and closed channels. Such
antagonists inhibit ion flux through a mechanism that does not
involve binding at the orthosteric sites.
[0007] Barbiturates, dissociative anesthetics, antidepressants, and
certain steroids have been shown to inhibit nicotinic receptors by
allosteric mechanisms, including open and closed channel blockade.
Studies of barbiturates support a model whereby binding occurs to
both open and closed states of the receptors, resulting in blockade
of the flow of ions. See, Dilger, J. P., Boguslavsky, R., Barann,
M., Katz, T., Vidal, A. M., Mechanisms of barbiturate inhibition of
acetylcholine receptor channels, Journal General Physiology 109:
401-414 (1997). Although the inhibitory action of local anesthetics
on nerve conduction is primarily mediated by blocking voltage-gated
sodium channels, nicotinic receptors are also targets of local
anesthetics. See, Arias, H. R., Role of local anesthetics on both
cholinergic and serotonergic ionotropic receptors, Neuroscience and
Biobehavioral Reviews 23: 817-843 (1999) and Arias, H. R. &
Blanton, M. P., Molecular and physicochemical aspects of local
anesthetics acting on nicotinic acetylcholine receptor-containing
membranes, Mini Reviews in Medicinal Chemistry 2: 385-410
(2002).
[0008] For example, tetracaine binds to the receptor channels
preferentially in the resting state. Dissociative anesthetics
inhibit several neuronal-type nicotinic receptors in clinical
concentration ranges, with examples such as phencyclidine (PCP)
(Connolly, J., Boulter, J., & Heinemann, S. F., Alpha 4-beta 2
and other nicotinic acetylcholine receptor subtypes as targets of
psychoactive and addictive drugs, British Journal of Pharmacology
105: 657-666 (1992)), ketamine (Flood, P. & Krasowski M. D.,
intravenous anesthetics differentially modulate ligand-gated ion
channels, Anesthesiology 92: 1418-1425 (2000); and Ho, K. K. &
Flood, P., Single amino acid residue in the extracellular portion
of transmembrane segment 2 in the nicotinic .alpha.7 acetylcholine
receptor modulates sensitivity to ketamine, Anesthesiology 100:
657-662 (2004)), and dizocilpine (Krasowski, M. D. & Harrison,
N. L., General anaesthetic actions on ligand-gated ion channels,
Cellular and Molecular Life Sciences 55: 1278-1303 (1999)). Studies
indicate that the dissociative anesthetics bind to a single or
overlapping sites in the resting ion channel, and suggest that the
ketamine/PCP locus partially overlaps the tetracaine binding site
in the receptor channel. Dizocilpine, also known as MK-801, is a
dissociative anesthetic and anticonvulsant which also acts as a
non-competitive antagonist at different nicotinic receptors.
Dizocilpine is reported to be an open-channel blocker of
.alpha.4.beta.2 neuronal nicotinic receptors. See, Buisson, B.,
& Bertrand, D., Open-channel blockers at the human
.alpha.4.beta.2 neuronal nicotinic acetylcholine receptor,
Molecular Pharmacology 53: 555-563 (1998).
[0009] In addition to their well-known actions on monoamine and
serotonin reuptake systems, antidepressants have also been shown to
modulate nicotinic receptors. Early studies showed that tricyclic
antidepressants act as non-competitive antagonists. See, Gumilar,
F., Arias, H. R., Spitzmaul, G., Bouzat, C., Molecular mechanisms
of inhibition of nicotinic acetylcholine receptors by tricyclic
antidepressants. Neuropharnmacology 45: 964-76 (2003).
Gartia-Colunga et al., report that fluoxetine, a selective
serotonin reuptake inhibitor (SSRI), inhibits membrane currents
elicited by activation of muscle or neuronal nicotinic receptors in
a non-competitive manner; either by increasing the rate of
desensitization and/or by inducing channel blockade. See,
Gartia-Colunga, J., Awad, J. N., & Miledi, R., Blockage of
muscle and neuronal nicotinic acetylcholine receptors by fluoxetine
(Prozac), Proceedings of the National Academy of Sciences USA 94:
2041-2044 (1997); and Gar ia-Colunga, J., Vazquez-Gomez, E., &
Miledi, R., Combined actions of zinc and fluoxetine on nicotinic
acetylcholine receptors, The Pharmacogenomics Journal 4: 388-393
(2004). Mecamylamine, previously approved for the treatment of
hypertension, is a classical non-competitive nicotinic receptor
antagonist, and is also well known to inhibit receptor function by
blocking the ion channel. See, Giniatullin, R. A., Sokolova, E. M.,
Di Angelantonio, S., Skorinkin, A., Talantova, M. V., Nistri, A.
Rapid Relief of Block by Mecamylamine of Neuronal Nicotinic
Acetylcholine Receptors of Rat Chromaffin Cells in Vitro: An
Electrophysiological and Modeling Study. Molecular Pharmacology 58:
778-787 (2000).
SUMMARY OF THE INVENTION
[0010] The present invention includes compounds of Formula I:
##STR00001##
wherein
[0011] each of R.sup.1 and R.sup.2 individually is H, C., alkyl, or
aryl-substituted C.sub.1-6 alkyl, or R.sup.1 and R.sup.2 combine
with the nitrogen atom to which they are attached to form a 3- to
8-membered ring, which ring may be optionally substituted with
C.sub.1-6 alkyl, aryl, C.sub.1-6 alkoxy, or aryloxy
substituents;
[0012] R.sup.3 is H, C.sub.1-6 alkyl, or C.sub.1-6
alkoxy-substituted C.sub.1-6 alkyl;
[0013] each of R.sup.4, R.sup.5, R.sup.6, and R.sup.7 individually
is H, C.sub.1-6 alkyl, or C.sub.1-6 alkoxy; L.sup.1 is a linker
species selected from the group consisting of CR.sup.5R.sup.9,
CR.sup.8R.sup.9CR.sup.10R.sup.11, and O;
[0014] L.sup.2 is a linker species selected from the group
consisting of CH.sub.2, CH.sub.2CH.sub.2, CH.sub.2CH.sub.2CH or
CH.sub.2CH.sub.2CH.sub.2CH.sub.2;
[0015] each of R.sup.8, R.sup.9, R.sup.10, and R.sup.11
individually is hydrogen or C.sub.1-6 alkyl; and the dashed line
indicates an optional double bond;
[0016] or a pharmaceutically acceptable salt thereof.
[0017] The present invention includes pharmaceutical compositions
comprising a compound of the present invention or a
pharmaceutically acceptable salt thereof. The pharmaceutical
compositions of the present invention can be used for treating or
preventing a wide variety of conditions or disorders, and
particularly those disorders characterized by dysfunction of
nicotinic cholinergic neurotransmission or the degeneration of the
nicotinic cholinergic neurons.
[0018] The present invention includes a method for treating or
preventing disorders and dysfunctions, such as CNS disorders and
dysfunctions, and also for treating or preventing certain
conditions, for example, alleviating pain, hypertension, and
inflammation, in mammals in need of such treatment. The methods
involve administering to a subject a therapeutically effective
amount of a compound of the present invention, including a salt
thereof, or a pharmaceutical composition that includes such
compounds.
DETAILED DESCRIPTION OF THE INVENTION
I. Compounds
[0019] One embodiment of the present invention includes compounds
of Formula I:
##STR00002##
wherein
[0020] each of R.sup.1 and R.sup.2 individually is H, C.sub.1-6
alkyl, or aryl-substituted C.sub.1-6 alkyl, or R.sup.1 and R.sup.2
combine with the nitrogen atom to which they are attached to form a
3- to 8-membered ring, which ring may be optionally substituted
with C.sub.1-6 alkyl, aryl, C.sub.1-6 alkoxy, or aryloxy
substituents;
[0021] R.sup.6 is H, C.sub.1-6 alkyl, or C.sub.1-6
alkoxy-substituted C.sub.1-6 alkyl;
[0022] each of R.sup.4, R.sup.5, R.sup.6, and R.sup.7 individually
is H, C.sub.1-6 alkyl, or C.sub.1-6 alkoxy;
[0023] L.sup.1 is a linker species selected from the group
consisting of CR.sup.8R.sup.9, CR.sup.8R.sup.9CR.sup.10R.sup.11,
and O;
[0024] L.sup.2 is a linker species selected from the group
consisting of CH.sub.2, CH.sub.2CH.sub.2, CH.sub.2CH.sub.2CH.sub.2,
or CH.sub.2CH.sub.2CH.sub.2CH.sub.2; [0025] each of R.sup.8,
R.sup.9, R.sup.10, and R.sup.11 individually is hydrogen or
C.sub.1-6 alkyl; and
[0026] the dashed line indicates an optional double bond;
[0027] or a pharmaceutically acceptable salt thereof.
[0028] In one embodiment, R.sup.1 is H and R.sup.2 is C.sub.1-6
alkyl. In one embodiment, R.sup.3 is C.sub.1-6 alkyl. In one
embodiment, each of R.sup.4, R.sup.5, R.sup.6, and R.sup.7 is H. In
one embodiment, L.sup.1 is CR.sup.8R.sup.9, and each of R.sup.8 and
R.sup.9 is hydrogen. In one embodiment, L.sup.2 is
CH.sub.2CH.sub.2. In one embodiment, the dashed line is a single
bond.
[0029] One aspect of the present invention includes a
pharmaceutical composition comprising a compound of the present
invention and a pharmaceutically acceptable carrier.
[0030] One aspect of the present invention includes a method for
the treatment or prevention of a disease or condition mediated by a
neuronal nicotinic receptor, specifically through the use of
non-competitive modulators (e.g., non-competitive antagonists),
including but not limited channel blockers, comprising the
administration of a compound of the present invention. In one
embodiment, the disease or condition is a CNS disorder. In another
embodiment, the disease or condition is inflammation or an
inflammatory response. In another embodiment, the disease or
condition is pain. In another embodiment, the disease or condition
is neovascularization. In another embodiment, the disease or
condition is hypertension. In another embodiment, the disease or
condition is another disorder described herein.
[0031] One aspect of the present invention includes use of a
compound of the present invention for the preparation of a
medicament for the treatment or prevention of a disease or
condition mediated by a neuronal nicotinic receptor, specifically
through the use of non-competitive antagonists, such as channel
blockers. In one embodiment, the disease or condition is a CNS
disorder. In another embodiment, the disease or condition is
inflammation or an inflammatory response. In another embodiment,
the disease or condition is pain. In another embodiment, the
disease or condition is neovascularization. In another embodiment,
the disease or condition is hypertension. In another embodiment,
the disease or condition is another disorder described herein.
[0032] One aspect of the present invention includes a compound of
the present invention for use as an active therapeutic substance.
One aspect, thus, includes a compound of the present invention for
use in the treatment or prevention of a disease or condition
mediated by a neuronal nicotinic receptor, specifically through the
use of non-competitive antagonists, such as channel blockers. In
one embodiment, the disease or condition is a CNS disorder. In
another embodiment, the disease or condition is inflammation or an
inflammatory response, in another embodiment, the disease or
condition is pain. In another embodiment, the disease or condition
is neovascularization. In another embodiment, the disease or
condition is hypertension. In another embodiment, the disease or
condition is another disorder described herein.
[0033] Particular diseases or conditions include depression,
including major depressive disorder, hypertension, irritable bowel
syndrome (IBS), including IBS-D (diarrhea predominant), over active
bladder (OAB), and addiction, including smoking cessation.
[0034] The scope of the present invention includes all combinations
of aspects and embodiments.
[0035] The following definitions are meant to clarify, but not
limit, the terms defined. If a particular term used herein is not
specifically defined, such term should not be considered
indefinite. Rather, terms are used within their accepted
meanings.
[0036] As used throughout this specification, the preferred number
of atoms, such as carbon atoms, will be represented by, for
example, the phrase "C., alkyl," which refers to an alkyl group, as
herein defined, containing the specified number of carbon atoms.
Similar terminology will apply for other preferred terms and ranges
as well. Thus, for example, C.sub.1-6 alkyl represents a straight
or branched chain hydrocarbon containing one to six carbon
atoms.
[0037] As used herein the term "alkyl" refers to a straight or
branched chain hydrocarbon, which may be optionally substituted,
with multiple degrees of substitution being allowed. Examples of
"alkyl" as used herein include, but are not limited to, methyl,
ethyl, propyl, isopropyl, isobutyl, n-butyl, tert-butyl, isopentyl,
and n-pentyl.
[0038] As used herein, the term "alkylene" refers to a divalent
group, such as "methylene," "ethylene," and "ethenylene," which
refer to divalent forms --CH.sub.2--, --CH.sub.2--CH.sub.2--, and
--CH.dbd.CH-- respectively.
[0039] As used herein, the term "aryl" refers to a single benzene
ring or fused benzene ring system which may be optionally
substituted, with multiple degrees of substitution being allowed.
Examples of "aryl" groups as used include, but are not limited to,
phenyl, 2-naphthyl, 1-naphthyl, anthracene, and phenanthrene.
Preferable aryl rings have five- to ten-members.
[0040] As used herein, a fused benzene ring system encompassed
within the term "aryl" includes fused polycyclic hydrocarbons,
namely where a cyclic hydrocarbon with less than maximum number of
noncumulative double bonds, for example where a saturated
hydrocarbon ring (cycloalkyl, such as a cyclopentyl ring) is fused
with an aromatic ring (aryl, such as a benzene ring) to form, for
example, groups such as indanyl and acenaphthalenyl, and also
includes such groups as, for non-limiting examples,
dihydronaphthalene and tetrahydronaphthalene.
[0041] As used herein the term "alkoxy" refers to a group
--OR.sup.a, where R.sup.a is alkyl as herein defined.
[0042] As used herein the term "aryloxy" refers to a group
--OR.sup.a, where R.sup.a is aryl as herein defined.
[0043] As used herein "amino" refers to a group --NR.sup.aR.sup.b,
where each of R.sup.a and R.sup.b is hydrogen. Additionally,
"substituted amino" refers to a group --NR.sup.aR.sup.b wherein
each of R.sup.a and R.sup.b individually is alkyl, arylalkyl or
aryl. As used herein, when either R.sup.a or R.sup.b is other than
hydrogen, such a group may be referred to as a "substituted amino"
or, for example if R.sup.a is H and R.sup.b is alkyl, as an
"alkylamino."
[0044] As used herein, the term "pharmaceutically acceptable"
refers to carrier(s), diluent(s), excipient(s) or salt forms of the
compounds of the present invention that are compatible with the
other ingredients of the formulation and not deleterious to the
recipient of the pharmaceutical composition.
[0045] As used herein, the term "pharmaceutical composition" refers
to a compound of the present invention optionally admixed with one
or more pharmaceutically acceptable carriers, diluents, or
excipients. Pharmaceutical compositions preferably exhibit a degree
of stability to environmental conditions so as to make them
suitable for manufacturing and commercialization purposes.
[0046] As used herein, the terms "effective amount", "therapeutic
amount", and "effective dose" refer to an amount of the compound of
the present invention sufficient to elicit the desired
pharmacological or therapeutic effects, thus resulting in an
effective treatment of a disorder. Treatment of a disorder may be
manifested by delaying or preventing the onset or progression of
the disorder, as well as the onset or progression of symptoms
associated with the disorder. Treatment of a disorder may also be
manifested by a decrease or elimination of symptoms, reversal of
the progression of the disorder, as well as any other contribution
to the well being of the patient.
[0047] The effective dose can vary, depending upon factors such as
the condition of the patient, the severity of the symptoms of the
disorder, and the manner in which the pharmaceutical composition is
administered. Typically, to be administered in an effective dose,
compounds may be administered in an amount of less than 5 mg/kg of
patient weight. The compounds may be administered in an amount from
less than about 1 mg/kg patient weight to less than about 100
.mu.g/kg of patient weight, and further between about 1 .mu.g/kg to
less than 100 .mu.g/kg of patient weight. The foregoing effective
doses typically represent that amount that may be administered as a
single dose, or as one or more doses that may be administered over
a 24 hours period.
[0048] The compounds of this invention may be made by a variety of
methods, including well-established synthetic methods, Illustrative
general synthetic methods are set out below and then specific
compounds of the invention are prepared in the working
Examples.
[0049] In the examples described below, protecting groups for
sensitive or reactive groups are employed where necessary in
accordance with general principles of synthetic chemistry.
Protecting groups are manipulated according to standard methods of
organic synthesis (T, W. Green and P. G. M. Wuts (1999) Protecting
Groups in Organic Synthesis, 3.sup.rd Edition, John Wiley &
Sons, herein incorporated by reference with regard to protecting
groups), These groups are removed at a convenient stage of the
compound synthesis using methods that are readily apparent to those
skilled in the art.
[0050] The selection of processes as well as the reaction
conditions and order of their execution shall be consistent with
the preparation of compounds of the present invention.
[0051] The present invention also provides a method for the
synthesis of compounds useful as intermediates in the preparation
of compounds of the present invention along with methods for their
preparation.
[0052] The compounds can be prepared according to the methods
described below using readily available starting materials and
reagents. In these reactions, variants may be employed which are
themselves known to those of ordinary skill in this art but are not
described in detail here.
[0053] Unless otherwise stated, structures depicted herein are also
meant to include compounds which differ only in the presence of one
or more isotopically enriched atoms. Compounds having the present
structure except for the replacement of a hydrogen atom by a
deuterium or tritium, or the replacement of a carbon atom by a
.sup.13C- or .sup.14C-enriched carbon are within the scope of the
invention. For example, deuterium has been widely used to examine
the pharmacokinetics and metabolism of biologically active
compounds, Although deuterium behaves similarly to hydrogen from a
chemical perspective, there are significant differences in bond
energies and bond lengths between a deuterium-carbon bond and a
hydrogen-carbon bond. Consequently, replacement of hydrogen by
deuterium in a biologically active compound may result in a
compound that generally retains its biochemical potency and
selectivity but manifests significantly different absorption,
distribution, metabolism, and/or excretion (ADME) properties
compared to its isotope-free counterpart. Thus, deuterium
substitution may result in improved drug efficacy, safety, and/or
tolerability for some biologically active compounds.
[0054] The compounds of the present invention may crystallize in
more than one form, a characteristic known as polymorphism, and
such polymorphic forms ("polymorphs") are within the scope of the
present invention. Polymorphism generally can occur as a response
to changes in temperature, pressure, or both. Polymorphism can also
result from variations in the crystallization process. Polymorphs
can be distinguished by various physical characteristics known in
the art such as x-ray diffraction patterns, solubility, and melting
point.
[0055] Certain of the compounds described herein contain one or
more chiral centers, or may otherwise be capable of existing as
multiple stereoisomers. The scope of the present invention includes
mixtures of stereoisomers as well as purified enantiomers or
enantiomerically/diastereomerically enriched mixtures. Also
included within the scope of the invention are the individual
isomers of the compounds represented by the formulae of the present
invention, as well as any wholly or partially equilibrated mixtures
thereof. The present invention also includes the individual isomers
of the compounds represented by the formulas above as mixtures with
isomers thereof in which one or more chiral centers are
inverted.
[0056] When a compound is desired as a single enantiomer, such may
be obtained by stereospecific synthesis, by resolution of the final
product or any convenient intermediate, or by chiral
chromatographic methods as are known in the art. Resolution of the
final product, an intermediate, or a starting material may be
effected by any suitable method known in the art. See, for example,
Stereochemistty of Organic Compounds (Wiley-Interscience,
1994).
[0057] The present invention includes a salt or solvate of the
compounds herein described, including combinations thereof such as
a solvate of a salt. The compounds of the present invention may
exist in solvated, for example hydrated, as well as unsolvated
forms, and the present invention encompasses all such forms.
[0058] Typically, but not absolutely, the salts of the present
invention are pharmaceutically acceptable salts. Salts encompassed
within the term "pharmaceutically acceptable salts" refer to
non-toxic salts of the compounds of this invention.
[0059] Examples of suitable pharmaceutically acceptable salts
include inorganic acid addition salts such as chloride, bromide,
sulfate, phosphate, and nitrate; organic acid addition salts such
as acetate, galactarate, propionate, succinate, lactate, glycolate,
malate, tartrate, citrate, maleate, fumarate, methanesulfonate,
p-toluenesulfonate, and ascorbate; salts with acidic amino acid
such as aspartate and glutamate; alkali metal salts such as sodium
salt and potassium salt; alkaline earth metal salts such as
magnesium salt and calcium salt; ammonium salt; organic basic salts
such as trimethylamine salt, triethylamine salt, pyridine salt,
picoline salt, dicyclohexylamine salt, and
N,N'-dibenzylethylenediamine salt; and salts with basic amino acid
such as lysine salt and arginine salt. The salts may be in some
cases hydrates or ethanol solvates.
[0060] Those of skill in the art of organic chemistry will
appreciate that more than one systematic name can be given to many
organic compounds. The scope of the present invention should not be
considered as lacking clarity due to the several potential naming
conventions possible for the compounds,
II. General Synthetic Methods
[0061] Those skilled in the art of organic synthesis will
appreciate that there exist multiple means of producing compounds
of the present invention, as well as means for producing compounds
of the present invention which are labeled with a radioisotope
appropriate to various uses.
[0062] One means of producing compounds of the present invention is
outlined in Scheme 1 (see Synthetic Examples). Thus, norcamphor
(2-norbornanone) can be alkylated adjacent to the carbonyl
functionality, using techniques well known to those of skill in the
art of organic synthesis. Typically, treatment of the ketone with
strong base (e.g., sodium hydride, sodium alkoxide, sodium amide)
to form an enolate intermediate, followed by treatment with an
alkyl halide or sulfonate, is used for such transformations. Under
certain conditions, the alkylation can be performed with an
.alpha.,.omega.-dihaloalkane (such as 1,3-dibromopropane), such
that a spiro linkage is formed. While Scheme 1 shows the formation
of a spirocyclobutane (Compound II), other ring sizes (e.g.,
spirocyclopentane) are also accessible in this manner, by using
other .alpha.,.omega.-dihaloalkanes. The carbonyl functionality can
subsequently be converted into an exocyclic methylene (Compound
III), using Wittig (or equivalent) chemistry. Treatment of
exo-methylene compounds with hydrogen cyanide (or similar reagents,
such as thiocyanates), in the presence of strong acid, can provide
the corresponding tertiary formamido compounds, in a process known
as the Ritter reaction. Reduction of the formamido compound, using
a hydride reducing agent, such as lithium aluminum hydride or
sodium bis(methoxyethoxy)aluminum hydride, gives the corresponding
secondary amine, Compound IV.
[0063] Alternatively, substituted 2-norbomanones can also be used
as starting materials in the transformation outlined in Scheme 2.
Thus, each of D-camphor and L-camphor (both commercially available)
can be transformed into stereoisomers of Compound V. Other ketone
starting materials can also be used. For instance, the homolog of
2-norbornanone, bicyclo[2,2,2]octan-2-one, can be made by
hydrogenation of bicyclo[2,2,2]oct-5-en-2-one, which in turn can be
made by procedures similar to those published by Kozikowski and
Schmiesing, J. Org. Chem, 48: 1000-1007 (1983), herein incorporated
by reference with regard to such reaction. Similarly,
7-oxabicyclo[2.2.1]hept-5-en-2-one, produced as described by Black
and Vogel, Helv. Chim. Acta 67: 1612 (1984), herein incorporated by
reference with regard to such reaction, can be hydrogenated to give
7-oxabicyclo[2.2.1]heptan-2-one. Each of these ketones is a
potential starting material for tranformations similar to those
shown in Schemes 1 and 2.
[0064] The spirocyclopropane functionality can be installed using
Simmons-Smith and similar chemistries. Thus, reaction of
3-methylene-2-norbornanone with diiodomethane in the presence of
zinc-copper couple gives
spiro[bicyclo[2.2.1]heptane-2,1'-cyclopropan]-3-one, which can then
be transformed into compounds of the resent invention utilizing
reactions already described. Certain spirocyclopropane-containing
compounds are known in the literature and also serve as a starting
point for synthesis of compounds of the present invention. See, for
instance, Gream and Pincombe, Aust. J. Chem. 27: 543-565 (1974),
herein incorporated by reference with regard to such reaction.
[0065] Secondary amines, such as Compounds IV and V, can be
converted into tertiary amines through the intermediacy of amides
and carbamates.
[0066] Thus, sequential treatment of such compounds with
di-tert-butyl dicarbonate and lithium aluminum hydride will produce
the corresponding N-methyl tertiary amine.
##STR00003##
##STR00004##
Camphor
[0067] The incorporation of specific radioisotopes is also
possible. For example, reductions of amides and carbamates with
lithium aluminum deuteride or lithium aluminum tritide reducing
agents can produce N-trideuteromethyl or N-tritritiomethyl amines.
Alternatively, generation of an amide or carbamate, in which the
carbonyl carbon is an .sup.11C, .sup.13C, or .sup.14C atom,
followed by reduction with lithium aluminum hydride, will produce
an amine with the .sup.11C, .sup.13C, or .sup.14C atom,
respectively, incorporated. The incorporation of specific
radioisotopes is often desirable in the preparation of compounds
that are to be used in a diagnostic setting (e.g., as imaging
agents) or in functional and metabolic studies.
III. Pharmaceutical Compositions
[0068] Although it is possible to administer the compound of the
present invention in the form of a bulk active chemical, it is
preferred to administer the compound in the form of a
pharmaceutical composition or formulation. Thus, one aspect the
present invention includes pharmaceutical compositions comprising
one or more compounds of Formula I and/or pharmaceutically
acceptable salts thereof and one or more pharmaceutically
acceptable carriers, diluents, or excipients. Another aspect of the
invention provides a process for the preparation of a
pharmaceutical composition including admixing one or more compounds
of Formula I and/or pharmaceutically acceptable salts thereof with
one or more pharmaceutically acceptable carriers, diluents or
excipients.
[0069] The manner in which the compound of the present invention is
administered can vary. The compound of the present invention is
preferably administered orally. Preferred pharmaceutical
compositions for oral administration include tablets, capsules,
caplets, syrups, solutions, and suspensions. The pharmaceutical
compositions of the present invention may be provided in modified
release dosage forms such as time-release tablet and capsule
formulations.
[0070] The pharmaceutical compositions can also be administered via
injection, namely, intravenously, intramuscularly, subcutaneously,
intraperitoneally, intraarterially, intrathecally, and
intracerebroventricularly. Intravenous administration is a
preferred method of injection. Suitable carriers for injection are
well known to those of skill in the art and include 5% dextrose
solutions, saline, and phosphate buffered saline.
[0071] The formulations may also be administered using other means,
for example, rectal administration. Formulations useful for rectal
administration, such as suppositories, are well known to those of
skill in the art. The compounds can also be administered by
inhalation, for example, in the form of an aerosol; topically, such
as, in lotion form; transdermally, such as, using a transdermal
patch (for example, by using technology that is commercially
available from Novartis and Alza Corporation), by powder injection,
or by buccal, sublingual, or intranasal absorption.
[0072] Pharmaceutical compositions may be formulated in unit dose
form, or in multiple or subunit doses
[0073] The administration of the pharmaceutical compositions
described herein can be intermittent, or at a gradual, continuous,
constant or controlled rate. The pharmaceutical compositions may be
administered to a warm-blooded animal, for example, a mammal such
as a mouse, rat, cat, rabbit, dog, pig, cow, or monkey; but
advantageously is administered to a human being. In addition, the
time of day and the number of times per day that the pharmaceutical
composition is administered can vary.
[0074] The compounds of the present invention may be used in the
treatment of a variety of disorders and conditions and, as such,
may be used in combination with a variety of other suitable
therapeutic agents useful in the treatment or prophylaxis of those
disorders or conditions. Thus, one embodiment of the present
invention includes the administration of the compound of the
present invention in combination with other therapeutic compounds.
For example, the compound of the present invention can be used in
combination with other NNR ligands (such as varenicline),
allosteric modulators of NNRs, antioxidants (such as free radical
scavenging agents), antibacterial agents (such as penicillin
antibiotics), antiviral agents (such as nucleoside analogs, like
zidovudine and acyclovir), anticoagulants (such as warfarin),
anti-inflammatory agents (such as NSAIDs), anti-pyretics,
analgesics, anesthetics (such as used in surgery),
acetylcholinesterase inhibitors (such as donepezil and
galantamine), antipsychotics (such as haloperidol, clozapine,
olanzapine, and quetiapine), immuno-suppressants (such as
cyclosporin and methotrexate), neuroprotective agents, steroids
(such as steroid hormones), corticosteroids (such as dexamethasone,
predisone, and hydrocortisone), vitamins, minerals, nutraceuticals,
anti-depressants (such as imipramine, fluoxetine, paroxetine,
escitalopram, sertraline, venlafaxine, and duloxetine), anxiolytics
(such as alprazolam and buspirone), anticonvulsants (such as
phenytoin and gabapentin), vasodilators (such as prazosin and
sildenafil), mood stabilizers (such as valproate and aripiprazole),
anti-cancer drugs (such as anti-proliferatives), antihypertensive
agents (such as atenolol, clonidine, amlopidine, verapamil, and
olmesartan), laxatives, stool softeners, diuretics (such as
furosemide), anti-spasmotics (such as dicyclomine), anti-dyskinetic
agents, and anti-ulcer medications (such as esomeprazole). Such a
combination of pharmaceutically active agents may be administered
together or separately and, when administered separately,
administration may occur simultaneously or sequentially, in any
order. The amounts of the compounds or agents and the relative
timings of administration will be selected in order to achieve the
desired therapeutic effect. The administration in combination of a
compound of the present invention with other treatment agents may
be in combination by administration concomitantly in: (1) a unitary
pharmaceutical composition including both compounds; or (2)
separate pharmaceutical compositions each including one of the
compounds. Alternatively, the combination may be administered
separately in a sequential manner wherein one treatment agent is
administered first and the other second. Such sequential
administration may be close in time or remote in time.
[0075] Another aspect of the present invention includes combination
therapy comprising administering to the subject a therapeutically
or prophylactically effective amount of the compound of the present
invention and one or more other therapy including chemotherapy,
radiation therapy, gene therapy, or immunotherapy.
IV. Method of Using Pharmaceutical Compositions
[0076] The compounds of the present invention can be used for the
prevention or treatment of various conditions or disorders for
which other types of nicotinic compounds have been proposed or are
shown to be useful as therapeutics, such as CNS disorders,
inflammation, inflammatory response associated with bacterial
and/or viral infection, pain, metabolic syndrome, autoimmune
disorders, addictions, obesity or other disorders described in
further detail herein. This compound can also be used as a
diagnostic agent (in vitro and in vivo). Such therapeutic and other
teachings are described, for example, in references previously
listed herein, including Williams et al., Drug News Perspec. 7(4):
205 (1994), Arneric et al., CNS Drug Rev. 1(1): 1-26 (1995),
Arneric et al., Exp. Opin. Invest. Drugs 5(1): 79-100 (1996),
Bencherif et al., J Pharmnnaco Exp. Ther. 279: 1413 (1996),
Lippiello et al., J. Pharmacol. Exp. Ther. 279: 1422 (1996), Damaj
et al., J. Pharmacol. Exp. Ther. 291: 390 (1999); Chiari et al.,
Anesthesiology 91: 1447 (1999), Lavand'homme and Eisenbach,
Anesthesiology 91: 1455 (1999), Holladay et al., J. Med. Chem.
40(28): 4169-94 (1997), Bannon et al., Science 279: 77 (1998), PCT
WO 94/08992. PCT WO 96/31475, PCT WO 96/40682, and U.S. Pat. No.
5,583,140 to Bencherif et al., U.S. Pat. No. 5,597,919 to Dull et
al., U.S. Pat. No. 5,604,231 to Smith et al. and U.S. Pat. No.
5,852,041 to Cosford et al.
CNS Disorders
[0077] The compounds and their pharmaceutical compositions are
useful in the treatment or prevention of a variety of CNS
disorders, including neurodegenerative disorders, neuropsychiatric
disorders, neurologic disorders, and addictions. The compounds and
their pharmaceutical compositions can be used to treat or prevent
cognitive deficits and dysfunctions, age-related and otherwise;
attentional disorders and dementias, including those due to
infectious agents or metabolic disturbances; to provide
neuroprotection: to treat convulsions and multiple cerebral
infarcts; to treat mood disorders, compulsions and addictive
behaviors; to provide analgesia; to control inflammation, such as
mediated by cytokines and nuclear factor kappa B; to treat
inflammatory disorders; to provide pain relief; and to treat
infections, as anti-infectious agents for treating bacterial,
fungal, and viral infections. Among the disorders, diseases and
conditions that the compounds and pharmaceutical compositions of
the present invention can be used to treat or prevent are:
age-associated memory impairment (AAMI), mild cognitive impairment
(MCI), age-related cognitive decline (ARCD), pre-senile dementia,
early onset Alzheimer's disease, senile dementia, dementia of the
Alzheimer's type, Alzheimer's disease, cognitive impairment no
dementia (CIND), Lewy body dementia, HIV-dementia, AIDS dementia
complex, vascular dementia, Down syndrome, head trauma, traumatic
brain injury (TBI), dementia pugilistica, Creutzfeld-Jacob Disease
and prion diseases, stroke, central ischemia, peripheral ischemia,
attention deficit disorder, attention deficit hyperactivity
disorder, dyslexia, schizophrenia, schizophreniform disorder,
schizoaffective disorder, cognitive dysfunction in schizophrenia,
cognitive deficits in schizophrenia, Parkinsonism including
Parkinson's disease, postencephalitic parkinsonism,
parkinsonism-dementia of Gaum, frontotemporal dementia Parkinson's
Type (FTDP), Pick's disease, Niemann-Pick's Disease, Huntington's
Disease, Huntington's chorea, dyskinesia, tardive dyskinesia,
spastic dystonia, hyperkinesia, progressive supranuclear palsy,
progressive supranuclear paresis, restless leg syndrome,
Creutzfeld-Jakob disease, multiple sclerosis, amyotrophic lateral
sclerosis (ALS), motor neuron diseases (MND), multiple system
atrophy (MSA), corticobasal degeneration, Guillain-Barre Syndrome
(GBS), and chronic inflammatory demyelinating polyneuropathy
(CIDP), epilepsy, autosomal dominant nocturnal frontal lobe
epilepsy, mania, anxiety, depression, including major depressive
disorder (MDD), premenstrual dysphoria, panic disorders, bulimia,
anorexia, narcolepsy, excessive daytime sleepiness, bipolar
disorders, generalized anxiety disorder, obsessive compulsive
disorder, rage outbursts, conduct disorder, oppositional defiant
disorder, Tourette's syndrome, autism, drug and alcohol addiction,
tobacco addiction and, thus, useful as an agent for smoking
cessation, compulsive overeating and sexual dysfunction,
[0078] Cognitive impairments or dysfunctions may be associated with
psychiatric disorders or conditions, such as schizophrenia and
other psychotic disorders, including but not limited to psychotic
disorder, schizophreniform disorder, schizoaffective disorder,
delusional disorder, brief psychotic disorder, shared psychotic
disorder, and psychotic disorders due to a general medical
conditions, dementias and other cognitive disorders, including but
not limited to mild cognitive impairment, pre-senile dementia,
Alzheimer's disease, senile dementia, dementia of the Alzheimer's
type, age-related memory impairment, Lewy body dementia, vascular
dementia, AIDS dementia complex, dyslexia, Parkinsonism including
Parkinson's disease, cognitive impairment and dementia of
Parkinson's Disease, cognitive impairment of multiple sclerosis,
cognitive impairment caused by traumatic brain injury, dementias
due to other general medical conditions, anxiety disorders,
including but not limited to panic disorder without agoraphobia,
panic disorder with agoraphobia, agoraphobia without history of
panic disorder, specific phobia, social phobia,
obsessive-compulsive disorder, post-traumatic stress disorder,
acute stress disorder, generalized anxiety disorder and generalized
anxiety disorder due to a general medical condition, mood
disorders, including but not limited to major depressive disorder,
dysthymic disorder, bipolar depression, bipolar mania, bipolar I
disorder, depression associated with manic, depressive or mixed
episodes, bipolar II disorder, cyclothymic disorder, and mood
disorders due to general medical conditions, sleep disorders,
including but not limited to dyssomnia disorders, primary insomnia,
primary hypersomnia, narcolepsy, parasomnia disorders, nightmare
disorder, sleep terror disorder and sleepwalking disorder, mental
retardation, learning disorders, motor skills disorders,
communication disorders, pervasive developmental disorders,
attention-deficit and disruptive behavior disorders, attention
deficit disorder, attention deficit hyperactivity disorder, feeding
and eating disorders of infancy, childhood, or adults, tic
disorders, elimination disorders, substance-related disorders,
including but not limited to substance dependence, substance abuse,
substance intoxication, substance withdrawal, alcohol-related
disorders, amphetamine or amphetamine-like-related disorders,
caffeine-related disorders, cannabis-related disorders,
cocaine-related disorders, hallucinogen-related disorders,
inhalant-related disorders, nicotine-related disorders,
opioid-related disorders, phencyclidine or
phencyclidine-like-related disorders, and sedative-, hypnotic- or
anxiolytic-related disorders, personality disorders, including but
not limited to obsessive-compulsive personality disorder and
impulse-control disorders.
[0079] Cognitive performance may be assessed with a validated
cognitive scale, such as, for example, the cognitive subscale of
the Alzheimer's Disease Assessment Scale (ADAS-cog). One measure of
the effectiveness of the compounds of the present invention in
improving cognition may include measuring a patient's degree of
change according to such a scale.
[0080] Regarding compulsions and addictive behaviors, the compounds
of the present invention may be used as a therapy for nicotine
addiction, including as an agent for smoking cessation, and for
other brain-reward disorders, such as substance abuse including
alcohol addiction, illicit and prescription drug addiction, eating
disorders, including obesity, and behavioral addictions, such as
gambling, or other similar behavioral manifestations of
addiction.
[0081] The above conditions and disorders are discussed in further
detail, for example, in the American Psychiatric Association:
Diagnostic and Statistical Manual of Mental Disorders, Fourth
Edition, Text Revision, Washington, D.C., American Psychiatric
Association, 2000. This Manual may also be referred to for greater
detail on the symptoms and diagnostic features associated with
substance use, abuse, and dependence,
Inflammation
[0082] The nervous system, primarily through the vagus nerve, is
known to regulate the magnitude of the innate immune response by
inhibiting the release of macrophage tumor necrosis factor (TNF).
This physiological mechanism is known as the "cholinergic
anti-inflammatory pathway" (see, for example, Tracey, "The
Inflammatory Reflex," Nature 420: 853-9 (2002)).
[0083] Excessive inflammation and tumor necrosis factor synthesis
cause morbidity and even mortality in a variety of diseases. These
diseases include, but are not limited to, endotoxemia, rheumatoid
arthritis, osteoarthritis, psoriasis, asthma, atherosclerosis,
idiopathic pulmonary fibrosis, and inflammatory bowel disease.
[0084] Inflammatory conditions that can be treated or prevented by
administering the compounds described herein include, but are not
limited to, chronic and acute inflammation, psoriasis, endotoxemia,
gout, acute pseudogout, acute gouty arthritis, arthritis,
rheumatoid arthritis, osteoarthritis, allograft rejection, chronic
transplant rejection, asthma, atherosclerosis,
mononuclear-phagocyte dependent lung injury, idiopathic pulmonary
fibrosis, atopic dermatitis, chronic obstructive pulmonary disease,
adult respiratory distress syndrome, acute chest syndrome in sickle
cell disease, inflammatory bowel disease, irritable bowel syndrome,
including diarrhea predominant IBS, Crohn's disease, ulcers,
ulcerative colitis, acute cholangitis, aphthous stomratitis,
cachexia, pouchitis, glomerulonephritis, lupus nephritis,
thrombosis, and graft vs. host reaction,
Inflammatory Response Associated with Bacterial and/or Viral
Infection
[0085] Many bacterial and/or viral infections are associated with
side effects brought on by the formation of toxins, and the body's
natural response to the bacteria or virus and/or the toxins. As
discussed above, the body's response to infection often involves
generating a significant amount of TNF and/or other cytokines. The
over-expression of these cytokines can result in significant
injury, such as septic shock (when the bacteria is sepsis),
endotoxic shock, urosepsis, viral pneumonitis and toxic shock
syndrome.
[0086] Cytokine expression is mediated by NNRs, and can be
inhibited by administering agonists or partial agonists of these
receptors. Those compounds described herein that are agonists or
partial agonists of these receptors can therefore be used to
minimize the inflammatory response associated with bacterial
infection, as well as viral and fungal infections. Examples of such
bacterial infections include anthrax, botulism, and sepsis. Some of
these compounds may also have antimicrobial properties.
Furthermore, the compounds can be used in the treatment of
Raynaud's disease, namely viral-induced painful peripheral
vasoconstriction.
[0087] These compounds can also be used as adjunct therapy in
combination with existing therapies to manage bacterial, viral and
fungal infections, such as antibiotics, antivirals and antifungals.
Antitoxins can also be used to bind to toxins produced by the
infectious agents and allow the bound toxins to pass through the
body without generating an inflammatory response. Examples of
antitoxins are disclosed, for example, in U.S. Pat. No. 6,310,043
to Bundle et al. Other agents effective against bacterial and other
toxins can be effective and their therapeutic effect can be
complemented by co-administration with the compounds described
herein.
Pain
[0088] The compounds can be administered to treat and/or prevent
pain, including acute, neurologic, inflammatory, neuropathic and
chronic pain. The compounds can be used in conjunction with opiates
to minimize the likelihood of opiate addiction (e.g., morphine
sparing therapy). The analgesic activity of compounds described
herein can be demonstrated in models of persistent inflammatory
pain and of neuropathic pain, performed as described in U.S.
Published Patent Application No. 20010056084 A1 (Allgeier et al)
(e.g., mechanical hyperalgesia in the complete Freund's adjuvant
rat model of inflammatory pain and mechanical hyperalgesia in the
mouse partial sciatic nerve ligation model of neuropathic
pain).
[0089] The analgesic effect is suitable for treating pain of
various genesis or etiology, in particular in treating inflammatory
pain and associated hyperalgesia, neuropathic pain and associated
hyperalgesia, chronic pain (e.g., severe chronic pain,
post-operative pain and pain associated with various conditions
including cancer, angina, renal or biliary colic, menstruation,
migraine, and gout). Inflammatory pain may be of diverse genesis,
including arthritis and rheumatoid disease, teno-synovitis and
vasculitis. Neuropathic pain includes trigeminal or herpetic
neuralgia, neuropathies such as diabetic neuropathy pain,
causalgia, low back pain and deafferentation syndromes such as
brachial plexus avulsion.
Neovascularization
[0090] Inhibition of neovascularization, for example, by
administering antagonists (or at certain dosages, partial agonists)
of nicotinic receptors can treat or prevent conditions
characterized by undesirable neovascularization or angiogenesis.
Such conditions can include those characterized by inflammatory
angiogenesis and/or ischemia-induced angiogenesis.
Neovascularization associated with tumor growth can also be
inhibited by administering those compounds described herein that
function as antagonists or partial agonists of nicotinic
receptors.
[0091] Specific antagonism of nicotinic receptors reduces the
angiogenic response to inflammation, ischemia, and neoplasia.
Guidance regarding appropriate animal model systems for evaluating
the compounds described herein can be found, for example, in
Heeschen, C. et al., "A novel angiogenic pathway mediated by
non-neuronal nicotinic acetylcholine receptors," J. Clin. Invest.
110(4):527-36 (2002).
[0092] Representative tumor types that can be treated using the
compounds described herein include SCLC, NSCLC, ovarian cancer,
pancreatic cancer, breast carcinoma, colon carcinoma, rectum
carcinoma, lung carcinoma, oropharynx carcinoma, hypopharynx
carcinoma, esophagus carcinoma, stomach carcinoma, pancreas
carcinoma, liver carcinoma, gallbladder carcinoma, bile duct
carcinoma, small intestine carcinoma, urinary tract carcinoma,
kidney carcinoma, bladder carcinoma, urothelium carcinoma, female
genital tract carcinoma, cervix carcinoma, uterus carcinoma,
ovarian carcinoma, choriocarcinoma, gestational trophoblastic
disease, male genital tract carcinoma, prostate carcinoma, seminal
vesicles carcinoma, testes carcinoma, germ cell tumors, endocrine
gland carcinoma, thyroid carcinoma, adrenal carcinoma, pituitary
gland carcinoma, skin carcinoma, hemangiomas, melanomas, sarcomas,
bone and soft tissue sarcoma, Kaposi's sarcoma, tumors of the
brain, tumors of the nerves, tumors of the eyes, tumors of the
meninges, astrocytomas, gliomas, glioblastomas, retinoblastomas,
neuromas, neuroblastomas, Schwannomas, meningiomas, solid tumors
arising from hematopoletic malignancies (such as leukemias,
chloromas, plasmacytomas and the plaques and tumors of mycosis
fungoides and cutaneous T-cell lymphomaileukemia), and solid tumors
arising from lymphomas.
[0093] The compounds can also be administered in conjunction with
other forms of anti-cancer treatment, including co-administration
with antineoplastic antitumor agents such as cis-platin,
adriamycin, daunomycin, and the like, and/or anti-VEGF (vascular
endothelial growth factor) agents, as such are known in the
art.
[0094] The compounds can be administered in such a manner that they
are targeted to the tumor site. For example, the compounds can be
administered in microspheres, microparticles or liposomes
conjugated to various antibodies that direct the microparticles to
the tumor. Additionally, the compounds can be present in
microspheres, microparticles or liposomes that are appropriately
sized to pass through the arteries and veins, but lodge in
capillary beds surrounding tumors and administer the compounds
locally to the tumor. Such drug delivery devices are known in the
art.
Other Disorders
[0095] In addition to treating CNS disorders, inflammation, and
neovascularization, and pain, the compounds of the present
invention can be also used to prevent or treat certain other
conditions, diseases, and disorders in which NNRs play a role.
Examples include autoimmune disorders such as lupus, disorders
associated with cytokine release, cachexia secondary to infection
(e.g., as occurs in AIDS, AIDS related complex and neoplasia),
obesity, pemphitis, urinary incontinence, overactive bladder (OAB),
diarrhea, constipation, retinal diseases, infectious diseases,
myasthenia, Eaton-Lambert syndrome, hypertension, preeclampsia,
osteoporosis, vasoconstriction, vasodilatation, cardiac
arrhythmias, type I diabetes, type II diabetes, bulimia, anorexia
and sexual dysfunction, as well as those indications set forth in
published PCT application WO 98/25619. The compounds of this
invention can also be administered to treat convulsions such as
those that are symptomatic of epilepsy, and to treat conditions
such as syphilis and Creutzfeld-Jakob disease.
[0096] Compounds of the present invention may be used to treat
bacterial infections and dermatologic conditions, such as pemphigus
folliaceus, pemphigus vulgaris, and other disorders, such as
acantholysis, where autoimmune responses with high ganglionic NNR
antibody titer is present. In these disorders, and in other
autoimmune diseases, such as Mysthenia Gravis, the fab fragment of
the antibody binds to the NNR receptor (crosslinking 2 receptors),
which induces internalization and degradation.
Diagnostic Uses
[0097] The compounds can be used in diagnostic compositions, such
as probes, particularly when they are modified to include
appropriate labels. For this purpose the compounds of the present
invention most preferably are labeled with the radioactive isotopic
moiety .sup.11C.
[0098] The administered compounds can be detected using position
emission topography (PET). A high specific activity is desired to
visualize the selected receptor subtypes at non-saturating
concentrations. The administered doses typically are below the
toxic range and provide high contrast images. The compounds are
expected to be capable of administration in non-toxic levels.
[0099] Determination of dose is carried out in a manner known to
one skilled in the art of radiolabel imaging. See, for example,
U.S. Pat. No. 5,969,144 to London et al.
[0100] The compounds can be administered using known techniques.
See, for example, U.S. Pat. No. 5,969,144 to London et al., as
noted. The compounds can be administered in formulation
compositions that incorporate other ingredients, such as those
types of ingredients that are useful in formulating a diagnostic
composition. Compounds useful in accordance with carrying out the
present invention most preferably are employed in forms of high
purity. See, U.S. Pat. No. 5,853,696 to Elmalch et al.
[0101] After the compounds are administered to a subject (e.g., a
human subject), the presence of that compound within the subject
can be imaged and quantified by appropriate techniques in order to
indicate the presence, quantity, and functionality, in addition to
humans, the compounds can also be administered to animals, such as
mice, rats, dogs, and monkeys. SPECT and PET imaging can be carried
out using any appropriate technique and apparatus. See Villemagne
et al., In: Arneric et al. (Eds.) Neuronal Nicotinic Receptors:
Pharmacology and Therapeutic Opportunities, 235-250 (1998) and U.S.
Pat. No. 5,853,696 to Elmalch et alt, each herein incorporated by
reference, for a disclosure of representative imaging
techniques.
V. Synthetic Examples
Example 1
Exo-N,3-dimethylspiro[bicyclo[2,2,1]heptane-2,1'-cyclobutan]-3-amine
[0102] To a solution of 2-norbornanone (norcamphor) (16.0 g, 145
mmol) and 1,3-dibromopropane (203 mmol, 20.7 mL; 41.1 g) in diethyl
ether (450 mL) was added sodium amide (363 mmol, 14.8 g) and the
mixture was stirred at reflux for 24 h. The mixture was poured into
200 mL of ice-water, and the organic layer was separated. The
aqueous layer was extracted with 200 mL of ether. The combined
ether extracts were concentrated, and the liquid residue was
distilled at 60-100.degree. C. at 10-20 Torr vacuum to obtain 14 g
of impure product. This was dissolved in 150 mL of hexanes and
stirred with a solution of potassium permanganate (12.0 g, 75.9
mmol) in water (150 mL) for 5 h. The biphasic mixture was filtered
through a bed of diatomaceous earth, which was then washed with
hexanes (100 mL). The hexane layer was separated, and the aqueous
layer was extracted with 600 mL of hexanes. The hexane layers were
combined, concentrated, and purified on silica gel column, eluting
with 10-40% ether in hexanes, to obtain
spiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-one (Compound II in
Scheme 1) (6.1 g, 28% yield) as oil. .sup.1H NMR (CDCl.sub.3, 400
MHz): .delta. 2.55-2.49 (m, 2H), 2.18-2.08 (m, 2H), 2.00-1.58 (m,
7H), 1.49-1.36 (m, 3H); LCMS (m/z): 151 (M+1).
[0103] To a suspension of (methyl)triphenylphosphonium bromide
(49.9 mmol, 18.2 g) in dry tetrahydrofuran (THF) (100 mL) at
-78.degree. C. was added n-butyllithium (46.5 mmol, 18.6 mL of 2.5
M solution in hexanes). The mixture was stirred for 30 min at
-78.degree. C. To this mixture was added
spiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-one (5.00 g, 33.3
mmol). The resulting mixture was stirred at ambient temperature for
20 h. Hexanes (300 mL) were added, and the mixture was filtered.
The filtrate was concentrated, and the residue was purified on an
80 g silica gel column, eluting with hexanes, to obtain
3-methylenespiro[bicyclo[2.2.1]heptane-2,1'-cyclobutane] (Compound
III in Scheme 1) (3.7 g, 75%) as oil. .sup.1H NMR (CDCl.sub.3, 400
MHz): .delta. 4.82 (s, 2H), 2.63 (brs, 1H). 2.22 (brs, 1H).
2.05-1.78 (m, 6H), 1.63-1.52 (m, 1H), 1.48-1.34 (m, 3H), 1.21-1.12
(m, 2H).
[0104] To a suspension of
3-methylenespiro[bicyclo[2.2.1]heptane-2,1'-cyclobutane] (2.10 g,
14.2 mmol) and potassium thiocyanate (14.2 mmol, 1.39 g) was slowly
added a solution of sulfuric acid (1.40 g; 14.3 mmol) in water
(0.52 mL) over 15 min at 50.degree. C., The solution was stirred at
85.degree. C. for 5.5 h. The solution was cooled to ambient
temperature, diluted with toluene (20 mL), and washed sequentially
with water (20 mL) and saturated aqueous sodium bicarbonate (10
mL). The toluene layer was collected, dried over anhydrous sodium
sulfate, and filtered. To the filtrate was added sodium
bis(methoxyethoxy)aluminum hydride (28 mmol, 7.9 mL of 65-70%
solution in toluene), and the resulting mixture was stirred at
85.degree. C. for 2 h. The mixture was cooled to 0.degree. C. and a
mixture of 3N aqueous sodium hydroxide (3 mL) and 5% sodium
hypochlorite (15 mL) was slowly added drop-wise, in intervals. The
toluene layer was separated and washed with water (30 mL). The
toluene layer was then extracted with 1 N aqueous hydrochloric acid
(2.times.10 mL). The toluene layer was discarded, and the combined
hydrochloric acid extracts were made basic by addition of 10%
aqueous sodium hydroxide (to pH10). The basic aqueous mixture was
extracted with ether (2.times.30 mL). The ether extracts were
collected, concentrated, and purified by silica gel column
chromatography, eluting with 0-40% CMA (chloroform:methanol:30%
aqueous ammonia, 9:1:0.1) in chloroform, to obtain
exo-N,3-dimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-amine
(0.38 g, 15% yield) (Compound IV in Scheme 1) as oil. The oil was
dissolved in 5 mL of dichloromethane, cooled in ice-bath, and
combined with 2 mL of 6 M aqueous hydrochloric acid. The mixture
was concentrated and vacuum dried to obtain the hydrochloride salt.
.sup.1H NMR (D.sub.2O, 400 MHz): .delta. 2.41 (s, 3H), 2.24-2.18
(m, 2H), 1.98-1.90 (m, 1H), 1.82-1.74 (m, 1H), 1.67-1.58 (m, 2H),
1.52-1.11 (m, 8H), 0.95 (s, 3H); LCMS (m/z): 180 (M+1).
[0105] The exo stereochemistry was established by NMR.
Example 2
Chiral chromatographic separation of
exo-N,3-dimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-amine
[0106]
Exo-N,3-dimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-amin-
e (2.0 g) was dissolved in 20 mL of acetonitrile and was separated
with 0.2 mL injections on chiral column (Chiral Pak AD-H, 5 micron,
250.times.20 cm), using 0.2% diethylamine in
acetonitrile/isopropanol (95:5), with a flow rate of 10 mL/min.
Fractions containing peak 1 (early eluting) and peak 2 (late
eluting) were separately concentrated. The two residues were
individually dissolved in 10 mL of dichloromethane, treated with 2
mL of 6N aqueous hydrochloric acid, and concentrated to dryness.
These hydrochloride salt products weighed 0.74 g (peak 1) and 0.48
g (peak 2), respectively.
Example 3
N,3-dimethylspiro[bicyclo[2.2.1]heptane-2,1-cyclopentan]-3-amine
[0107] To a solution of 2-norbornanone (25.0 g, 227 mmol) and
1,4-dibromobutane (68.0 g, 317 mmol) in diethyl ether (700 mL) was
added sodium amide (23.1 g, 567 mmol). This mixture was heated at
reflux for 24 h, cooled and poured into 200 mL of ice-water. The
organic layer was collected, and the aqueous layer was extracted
with 200 mL of diethyl ether. The combined diethyl ether extracts
were concentrated, and the residue was distilled at 65-80.degree.
C. at 7-15 Torr to obtain 19 g of impure product. This was
dissolved in hexanes (500 mL) and stirred with aqueous potassium
permanganate (30 g, 0.19 mol, in 500 mL) for 5 h. The mixture was
filtered, and the hexane layer was collected. The aqueous layer was
extracted with 600 mL of hexanes. The combined hexane layers were
concentrated, and the residue purified on a silica gel column,
eluting with 5-15% ethyl acetate in hexanes, to obtain
spiro[bicyclo[2.2.1]heptane-2,1'-cyclopentan]-3-one (12.6 g: 33.8%)
as oil. .sup.1H NMR (CDCl.sub.3, 400 MHz): .delta. 2.56 (d, J=5.1
Hz, 1H), 2.24 (bs, 1H), 1.44-1.88 (m, 14H); LCMS (m/z): 165
(M+1).
[0108] To a suspension of (methyl)triphenylphosphonium bromide
(17.6 g, 48.4 mmol) in THF (100 mL) at -78.degree. C. was added
n-butyllithium (18.1 mL of 2.5 M solution in THF, 45 mmol) and the
mixture was stirred 30 min, To this mixture was added
spiro[bicyclo[2.2.1]heptane-2,1'-cyclopentan]-3-one (5.30 g, 32.3
mmol), and the reaction was stirred at ambient temperature for 18
h. Hexanes (200 mL) were added, and the mixture was filtered. The
filtrate was concentrated, and the residue was purified on an 80 g
silica gel column, eluting with hexanes, to obtain
3-methylenespiro[bicyclo[2.2.1]heptane-2,1'-cyclopentane] (4.80 g,
91.7%) as oil.
[0109] Sulfuric acid (1.61 mL, 2.96 g, 30.2 mmol) was slowly added
to a suspension of
3-methylenespiro[bicyclo[2.2.1]heptane-2,1'-cyclopentane](4.80 g,
29.6 mmol) and potassium thiocyanate (2.96 g, 30.2 mmol) at
50.degree. C. The reaction mixture was then stirred at 85.degree.
C. for 5.5 h, cooled to ambient temperature, diluted with toluene
(30 mL) and washed with water (20 mL) followed by with saturated
aqueous sodium bicarbonate (10 mL). The toluene layer was dried
over anhydrous sodium sulfate and filtered. To the filtrate was
added sodium bis(methoxyethoxy)aluminum hydride (40% solution in
toluene, 2 equivalents) and the reaction was stirred at 85.degree.
C. for 2 h. The reaction was cooled to 000, and a solution of 3N
aqueous sodium hydroxide (20 mL) in 5% aqueous sodium hypochlorite
(35 mL) was slowly added (drop-wise at intervals). The toluene
layer was separated and washed with water (30 mL). The toluene
layer was then extracted with 1N aqueous hydrochloric acid
(2.times.10 mL) and discarded. The aqueous hydrochloric acid layer
was made basic (to pH 10) by addition of 10% aqueous sodium
hydroxide and extracted with diethyl ether. The diethyl ether
extracts were concentrated, and the residue was purified by silica
gel column chromatography, using 0-40% CMA (chloroform:methanol:30%
aqueous ammonia, 9:1:0.1) in chloroform to obtain
N,3-dimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclopentan]-3-amine
(1.2 g, 53%) as oil. .sup.1H NMR (CDCl.sub.3, 400 MHz): <2.28
(s. 3H), 2.24 (bs, 1H), 1.84-1.76 (m, 2H), 1.73-1.68 (m, 1H),
1.62-1.52 (m, 4H), 1.48-1.24 (m, 7H), 1.09-1.05 (nm, 1H), 1.04 (s,
3H); LCMS (m/z): 194 (M+1).
Example 4
General procedure for Making N-substituted
spiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-amines
[0110] Certain N-substituted
spiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-amines can be
prepared by the reductive amination of
spiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-one. The following
procedure, utilizing methylamine and providing
N-methylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-amine
trifluoroacetate, is exemplary. Reductive aminations utilizing
dimethylamine, azetidine, and pyrrolidine were performed in a
similar fashion,
[0111] To a solution of
spiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-one (0.15 g, 1.0
mmol) and methylamine (4.0 mL of 2.0 M solution in THF, 8.0 mmol)
in 1,2-dichloroethane (10 mL) was added acetic acid (0.2 mL) and
sodium triacetoxyborohydride (0.85 g, 4.0 mmol), The reaction was
stirred at ambient temperature for 48 h, diluted with
dichloromethane (10 mL), washed with saturated aqueous sodium
bicarbonate solution (10 mL), and concentrated. The residue was
purified on preparative HPLC, eluting with mixtures of 0.05% formic
acid in water and 0.05% formic acid in acetonitrile. Selected
fractions were concentrated, and the residue was dissolved in
methanol (2 mL). Trifluoroacetic acid (0.1 mL) was added, and the
mixture was concentrated and vacuum dried to obtain
N-methylspiro[bicyclo[22.2.1]heptane-2,1'-cyclobutan]-3-amine
trifluoroacetate (0.088 g) as gum. .sup.1H NMR (CD.sub.3OD, 400
MHz): .delta. 3.06-3.02 (m, 1H), 2.568 (s, 3H), 2.54 (brs, 1H),
2.34 (brs, 1H), 2.02-1.83 (m, 6H), 1.56-1.42 (m, 5H), 1.26-1.32 (m,
1H); LCMS (m/z): 166 (M+1).
Example 5
(1S,3R,4R)--N,4,7,7-Tetramethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan-
]-3-amine hydrochloride and
(1S,3S,4R)--N,4,7,7-tetramethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobuta-
n]-3-amine hydrochloride
[0112] The following chemistry, using D-camphor as a starting
material, was repeated using L-camphor as a starting material,
yielding products that are enantiomeric to those described
here.
[0113] A mixture of D-(+)-camphor (4.40 g, 28.9 mmol) and sodium
amide (2.50 g, 61.5 mmol) in toluene (100 mL) was stirred at 100'C
for 30 min. A solution of 1,3-dibromopropane (31.8 mmol, 3.24 mL,
6.42 g) in toluene (20 mL) was added, and the reaction was heated
at reflux for 3 h. The reaction was cooled to ambient temperature,
washed with water (100 mL), dried over anhydrous sodium sulfate and
concentrated. The residue was dissolved in 5% methanol in
dichloromethane (80 mL) and cooled to -78'C. Ozone was passed
through the solution until the blue color persisted (.about.10
minutes). Dimethyl sulfide (2 mL) was then added, and the reaction
was warmed slowly to ambient temperature. The reaction mixture was
concentrated, and the residue was purified on a silica gel column
(40 g), eluting with 0-20% ether in hexanes, to obtain (1
S,4R)-4,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-one
(1.66 g, 29.9% yield) as oil. .sup.1H NMR (CDCl.sub.3, 400 MHz):
.delta. 2.26 (m, 1H), 2.10-1.97 (m, 5H), 1.85-1.1.66 (m, 2H).
1.62-1.53 (m, 1H), 1.47-1.40 (m, 1H), 1.28-1.19 (m, 1H), 0.94 (s,
3H), 0.88 (s, 3H), 0.75 (s, 3H); LCMS (m/z): 193 (M+1).
[0114] A mixture of
(1S,4R)-4,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-one
(1.60 g, 8.32 mmol) and formamide (10 mL) in formic acid (7 mL) was
stirred at 175'C for 72 h. The reaction mixture was cooled to
ambient temperature, poured into 200 mL of ice-water, and extracted
with ether (2.times.50 mL). The combined ether extracts were washed
with water (40 mL), dried over anhydrous sodium sulfate and
concentrated to obtain
N-(4,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-yl)forma-
mide (1.55 g, 84.2% yield) as gum.
[0115] To a solution of
N-(4,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-yl)forma-
mide (1.50 g, 6.78 mmol) in THF (40 mL) at 0.degree. C. was slowly
added lithium aluminum hydride (27.1 mmol, 27.1 mL of 1.0 M
solution in THF). After complete addition, the reaction was
refluxed for 48 h. The reaction mixture was cooled to 0.degree. C.
and quenched by addition, in portions, of solid sodium sulfate
decahydrate (10 g). After stirring for 1 h, this mixture was
filtered, and the filtrate was concentrated. The residue was
purified on a 40 g silica gel column, using 0-100% CMA
(chloroform:methanol:30% aqueous ammonia; 9:1:0.1) in chloroform as
the eluent, to obtain an exo-amine product,
(1S,3R,4R)--N,4,7,7-tetramethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobuta-
n]-3-amine (0.49 g; 35% yield), and an endo-amine product, (1
S,3S,4R)--N,4,7,7-tetramethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-
-3-amine (0.30 g; 21% yield), both as oils. The two products were
converted to their hydrochloride salts by dissolving each in 1 mL
of concentrated hydrochloric acid and concentrating and vacuum
drying the samples. .sup.1H NMR of
exo-(1S,3R,4R)--N,4,7,7-tetramethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclo-
butan]-3-amine hydrochloride (D.sub.2O, 400 MHz): .delta. 2.80 (s,
3H), 2.72 (brs, 1H), 2.22-1.91 (m, 4H), 1.84-1.72 (m, 3H),
1.54-1.45 (m, 2H), 1.38-1.31 (m, 1H), 1.10-1.01 (m, 1H), 0.87 (s,
3H), 0.75 (s. 3H), 0.72 (s, 3H); LCMS (m/z): 208 (M+1). .sup.1H NMR
of
endo-(1S,3S,4R)--N,4,7,7-tetramethylspiro[bicyclo[2.2.1]heptane-2,1'-cycl-
obutan]-3-amine hydrochloride (D.sub.2O, 400 MHz): .delta. 3.12
(brs, 1H), 2.79 (s, 3H), 2.26-2.16 (m, 1H), 2.01-1.85 (m, 3H),
1.78-1.69 (m, 3H), 1.60-1.51 (m, 1H), 1.36-1.24 (m, 2H), 1.08-1.00
(m, 1H), 0.85 (s, 3H), 0.78 (s, 3H), 0.75 (s, 3H); LCMS (m/z): 208
(M+1).
Example 6
General procedure for converting secondary amines into N-methyl
tertiary amines
[0116] Certain N-methyl tertiary amines can be prepared by the
reductive amination of the corresponding secondary amines. The
following procedure, utilizing formaldehyde and providing exo-(1
S,3R,4R)--N,N,4,7,7-pentamethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobuta-
n]-3-amine hydrochloride, is exemplary. Analogous N-methylation
reactions were carried out on a variety of secondary amines.
[0117] To a solution of (1
S,3R,4R)--N,4,7,7-tetramethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobuta
n]-3-amine (0.10 g, 0.48 mmol) and 30% aqueous formaldehyde (1 mL)
in methanol (4 mL) was added sodium triacetoxyborohydride (0.31 g,
1.4 mmol), and the reaction was stirred at ambient temperature for
16 h. The reaction was quenched with saturated aqueous sodium
bicarbonate solution (30 mL) and extracted with dichloromethane
(2.times.30 mL). Formic acid (0.2 mL) was added to the combined
organic extracts and they were concentrated on rotary evaporator.
The residue was purified by preparative LCMS, using mixtures of
0.05% formic acid in water and 0.05% formic acid in acetonitrile.
Selected fractions were combined, made basic (pH 9) by addition of
10% aqueous sodium hydroxide and extracted with dichloromethane
(2.times.30 mL). The combined organic extracts were treated with
0.5 mL of concentrated hydrochloric acid. This mixture was
concentrated and vacuum dried to obtain
(1S,3R,4R)--N,N,4,7,7-pentamethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobu-
tan]-3-amine hydrochloride (0.06 g) as white solid. .sup.1H NMR
(D.sub.2O, 400 MHz): .delta. 3.27 (s, 3H), 3.19 (s, 3H), 3.10 (s,
1H), 2.55-2.28 (m, 4H), 2.18-1.97 (m, 3H), 1.80-1.60 (m, 3H).
1.45-1.36 (m, 1H), 1.28 (s, 3H), 1.02 (s, 3H), 1.01 (s, 3H); LCMS
(m/z): 222 (M+1).
Example 7
N-Methylspiro[bicyclo[2.2.1]heptane-2,1'-cyclopropan]-3-amine
trifluoroacetate
[0118] Neat 3-methylene-2-norbornanone (8.9 g, 73 mmol), followed
by neat diiodomethane (8.30 mL, 103 mmol), were added to a slurry
of zinc-copper couple (9.1 g, 57 mmol) in diethyl ether (75 mL).
The resulting mixture was heated at reflux for 6 h. A second
portion of zinc-copper couple (10 g) was added, and reflux was
continued for an additional 16 h. The reaction was then quenched
with water (200 mL) and diluted with diethyl ether (200 mL). The
biphasic mixture was filtered through a pad of diatomaceous earth.
The organic layer was separated, washed with 10% aqueous
hydrochloric acid (2.times.50 mL), dried over anhydrous magnesium
sulfate and concentrated. The residue was passed through a silica
gel column, eluting with dichloromethane. Selected fractions were
concentrated, and the residue was vacuum distilled on a
bulb-to-bulb distillation apparatus at 3 Torr, collecting
spiro[bicyclo[2.2.1]heptane-2,1'-cyclopropan]-3-one (1.6 g) as oil.
.sup.1H NMR (CDCl.sub.3, 400 MHz): .delta. 2.71-2.69 (m, 1H), 2.06
(brs, 1H), 2.00-1.72 (m, 3H). 1.66-1.57 (m, 3H), 1.09-1.00 (m, 2H),
0.91-0.89 (m, 1H), 0.80-0.75 (m, 1H).
[0119] To a solution of
spiro[bicyclo[2.2.1]heptane-2,1'-cyclopropan]-3-one (0.13 g, 0.96
mmol) and methylamine (4.0 mL of 2.0 M solution in THF, 8.0 mmol)
in 1,2-dichloroethane (10 mL) was added acetic acid (0.2 mL) and
sodium triacetoxyborohydride (0.85 g, 4.0 mmol) and the reaction
was stirred at ambient temperature for 48 h. The reaction was
diluted with dichloromethane (10 mL), washed with saturated aqueous
sodium bicarbonate solution (10 mL), and concentrated. The residue
was purified on preparative HPLC, eluting with mixtures of 0.05%
formic acid in water and 0.05% formic acid in acetonitrile.
Selected fractions were concentrated, and the residue was dissolved
in methanol (2 mL). Trifluoroacetic acid (0.1 mL) was added, and
the mixture was concentrated and vacuum dried, to obtain
N-methylspiro[bicyclo[2.2.1]heptane-2,1'-cyclobutan]-3-amine
trifluoroacetate (0,005 g) as gum, .sup.1H NMR (CD.sub.3OD, 400
MHz): .delta. 2.76 (brs, 1H), 2.59 (s, 3H), 1.85-1.82 (m, 1H),
1.69-1.55 (m, 6H), 1.34-1.28 (m, 1H), 0.83-0.78 (m, 1H), 0.67-0.62
(m, 1H), 0.58-0.50 (m, 2H); LCMS (m/z): 152 (M+1).
Example 8
N,3-dimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclopropan]-3-amine
hydrochloride
[0120] To a solution of
(3-methylspiro[bicyclo[2.2.1]hept[5]ene-2,1'-cyclopropane]-3-yl)methanol
(9.4 g, 57 mmol), prepared as described by Gream and Pincombe,
Aust. J. Chem. 27: 543-565 (1974), herein incorporated by reference
with regard to such preparation, in methanol (20 mL) was added 0.8
g 10% Pd/C (wet) under nitrogen. The atmosphere was replaced with
hydrogen (50 psi), and the mixture was shaken for 4 h at ambient
temperature. The reaction was then filtered through a pad of
diatomaceous earth, which was then washed with methanol. The
filtrate was concentrated to yield 9.60 g of
(3-methylspiro[bicyclo[2.2.1]heptane-2,1'-cyclopropane]-3-yl)methanol
as a white solid (99%).
[0121] To a stirred solution of chromium trioxide (8.0 g, 76 mmol)
in water (30 mL) cooled in an ice bath, was added carefully 96%
sulfuric acid (6.9 mL, 120 mmol). While continuing to cool and stir
the oxidant solution in an ice bath, a solution of
(3-methylspiro[bicyclo[22.1]heptane-2,1'-cyclopropane]-3-yl)methanol
(9.5 g; 57 mmol) in acetone (115 mL) was added over a 20 min
period. After complete addition, the reaction mixture was stirred
for 3 h while warming to ambient temperature. The reaction was then
diluted with water (45 mL) and ethyl acetate (200 mL). Slowly,
sodium bisulfite powder was added until the brown color dissipated
and the aqueous layer became blue. The phases were then separated,
and the aqueous layer was washed with ethyl acetate (2.times.100
mL). The organic layers were combined and dried over anhydrous
magnesium sulfate. The drying agent was removed by filtration, and
the filtrate was concentrated to yield a green oil. The oil was
purified by silica gel (200 g) column chromatography, using a 0-50%
ethyl acetate in hexanes gradient. Selected fractions were combined
and concentrated to yield 6.0 g of
3-methylspiro[bicyclo[2.2.1]heptane-2,1'-cyclopropane]-3-carboxylic
acid as a white solid (58%).
[0122] To a stirred solution of
3-methylspiro[bicyclo[2.2.1]heptane-2,1'-cyclopropane]-3-carboxylic
acid (2.8 g, 15 mmol) and triethylamine (2.6 mL, 18 mmol) in
toluene (70 mL) cooled in an ice bath, was added diphenylphosphonic
azide (3.5 mL, 16 mmol). The reaction mixture was warmed to
90.degree. C. and stirred for 2.5 h. Benzyl alcohol (1.7 mL, 16
mmol) was then added to the reaction, and the mixture was stirred
an additional 16 h at 90.degree. C. The reaction mixture was cooled
and concentrated. The residue was purified by silica gel (60 g)
column chromatography, using a 0-15% ethyl acetate in hexanes
gradient. Selected fractions were combined and concentrated to
yield 1.6 g of a mixture of materials, including
3-isocyanato-3-methylspiro[bicyclo[2.2.1]heptane-2,1'-cyclopropane]
and the corresponding benzyl carbamate, as a white solid. This
mixture was dissolved in dry THF (16 mL) and cooled in an ice bath.
Lithium aluminum hydride (8.5 mL of 2.0M in THF, 17 mmol) was
slowly added. The reaction was warmed to 55.degree. C. for 3 h. The
reaction was then cooled in an ice-bath and diluted with diethyl
ether (20 mL). The reaction was quenched by careful addition of
water until gas evolution subsided. The resulting viscous white
slurry was stirred at ambient temperature for 1 h, during which
time the salts became more granular. The slurry was then filtered
through a pad of diatomaceous earth, and the filter cake was washed
with diethyl ether (10 mL) and then ethyl acetate (10 mL). The
combined filtrates were extracted with 6M hydrochloric acid
(3.times.4 mL). The aqueous extracts were combined and concentrated
on a rotary evaporator to yield 1.6 g of
N,3-dimethylspiro[bicyclo[2.2.1]heptane-2,1'-cyclopropan]-3-amine
hydrochloride as a white solid (53% yield). .sup.1H NMR (400 MHz,
D.sub.2O): .sctn.2.52 (s, 1H), 2.46 (s, 3H), 1.72 (d, J=11 Hz, 1H),
1.49-1.41 (m, 3H), 1.39-1.32 (m, 2H), 1.28 (d, J=11 Hz, 1H), 1.02
(s, 3H), 0.59-0.51 (m, 3H), 0.45-0.43 (m, 1H); LCMS (m/z): 166
(M+1).
Example 9
N,3-dimethylspiro[bicyclo[2.2.2]oct[5]ene-2,1'-cyclopentan]-3-amine
hydrochloride and
N,3-dimethylspiro[bicyclo[2.2.2]octane-2,1'-cyclopentan]-3-amine
hydrochloride
[0123] The intermediate, bicyclo[2,2,2]oct-5-en-2-one, was made
using procedures described by Kozikowski and Schmiesing, J. Org.
Chem. 48: 1000-1007 (1983), previously incorporated by reference
with regard to such reaction, and then subsequently transformed
into
N,3-dimethylspiro[bicyclo[2.2.2]oct[5]ene-2,1'-cyclopentan]-3-amine
and
N,3-dimethylspiro[bicyclo[2.2.2]octane-2,1'-cyclopentan]-3-amine.
[0124] A mixture of acrylonitrile (79.4 g. 1.49 mol),
1,3-cyclohexadiene (60 g, 0.75 mol), and hydroquinone (1.1 g, 10
mmol) was sealed in a tube and heated at 120.degree. C. for 18 h.
The resulting mixture was concentrated and purified by
chromatography on silica gel, eluting with mixtures of ethyl
acetate (0.5% to 1%) in petroleum ether, to give a separable
mixture of isomers (presumably endo/exo) of
5-cyanobicyclo[2,2,2]oct-2-ene (64 g, 64% yield) as a white
semisolid. .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 1.32 (m, 2H),
1.75 (m, 3H), 2.04 (m, 1H), 2.43 (m, 1H), 2.62 (m, 1H), 2.78 (m,
1H), 6.23 (m, 1H), 6.30 (m. 1H); .sup.1H NMR (300 MHz, CDCl.sub.3)
.delta. 1.28 (m, 2H), 1.50 (m, 3H), 1.94 (m, 1H), 2.68 (m, 2H),
2.87 (m, 1H), 6.29 (m, 1H), 6.44 (m, 1H); LCMS (m/z): 134
(M+1).
[0125] To a refluxing mixture of pyridine (14.2 g, 0.180 mol),
phosphorus pentachloride (28.0 g, 0.135 mol), and chloroform (100
mL) was added drop-wise a solution of
5-cyanobicyclo[2,2,2]oct-2-ene (12 g, 90 mmol) in chloroform (50
mL). The resulting mixture was heated at reflux for 15 h, cooled,
and poured onto ice. The organic layer was concentrated, and the
residue was purified by chromatography on silica gel, eluting with
mixtures of ethyl acetate (0.5% to 1%) in petroleum ether, to give
5-chloro-5-cyanobicyclo[2,2,2]oct-2-ene (14.3 g, 95% yield) as a
white semisolid. .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 1.3-1.5
(m, 3H), 2.02-2.18 (m, 2H), 2.51 (m, 1H), 2.72 (m, 1H), 3.12 (m,
1H), 6.22 (m, 1H), 6.41 (m, 1H); GCMS (m/z): 167.
[0126] To a stirred solution of
5-chloro-5-cyanobicyclo[2,2,2]oct-2-ene (65 g, 0.39 mol)
(representing several runs of the foregoing procedure) in dimethyl
sulfoxide (500 mL) was added potassium hydroxide (87.4 g, 1.56 mol)
and water (30 mL). The resulting mixture was stirred at room
temperature for 15 h, diluted with water (1000 mL) and extracted
with ether (4.times.500 mL). The combined ether extracts were
washed with brine, dried over anhydrous sodium sulfate, and
concentrated. The residue was purified by chromatography on silica
gel, eluting with mixtures of diethyl ether (1% to 5%) in petroleum
ether, to give bicyclo[2,2,2]oct-5-en-2-one (23.8 g, 50% yield) as
a white solid. .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 1.53-1.84
(m, 4H), 2.01-2.02 (m, 2H), 2.96-2.99 (m, 1H), 3.11-3.13 (m, 1H),
6.15-6.21 (m, 1H), 6.43-6.48 (m, 1H); GCMS (m/z): 122.
[0127] n-Butyllithium (56.5 mL of 1.6 M in hexanes, 90.4 mmol) was
added to a solution of diisopropylamine (11.2 mL, 8.05 g, 79.6
mmol) in dry THF (108 mL) at -78.degree. C. The mixture was warmed
to 0'C and stirred for 30 min. The solution was again cooled to
-78.degree. C., and bicyclo[2,2,2]oct-5-en-2-one (5.00 g, 36.2
mmol) dissolved in THF (10 mL) was added. The reaction was stirred
for 30 min at -78'C, and then hexamethylphosphoric triamide (13.9
mL, 14.3 g, 79.6 mmol) followed by 1,4-dibromobutane (4.76 mL, 8.59
g, 39.8 mmol) were added. The reaction mixture was warmed to
ambient temperature, stirred for 16 h, quenched with saturated
aqueous ammonium chloride (50 mL), diluted with ether (100 mL), and
washed with water (3.times.50 mL). The organic layer was dried over
anhydrous sodium sulfate, filtered, and concentrated. The residue
was purified on a 120 g silica column, eluting with 100% hexanes
for 4 column volumes, followed by a step gradient to 9:1
hexanes/ethyl acetate. Selected fractions were concentrated to
yield spiro[bicyclo[2.2.2]oct[5]ene-2,1'-cyclopentan]-3-one (5.1 g;
.about.90% pure by GC/MS) as a clear oil. The material was carried
forward without further purification, by dissolving in dry THF (20
mL) and cooling to -78.degree. C. Methylmagnesium bromide (28.6 mL
of 3.0 M in diethyl ether, 85.8 mmol) was then added, and the
reaction was slowly warmed to ambient temperature. The reaction was
stirred at ambient temperature for 18 h and quenched by careful
addition of saturated aqueous ammonium chloride. The reaction was
transferred to a separatory funnel, and the aqueous layer was
removed. The organic layer was washed twice with water (10 mL),
dried over anhydrous sodium sulfate, filtered, and concentrated.
The remaining material (colorless oil) was a mixture of
3-methylspiro[bicyclo[2.2.2]oct[5]ene-2,1'-cyclopentan]-3-ol (4.9
g) and starting material.
[0128] Without further purification, the sample generated
immediately above was combined with sodium cyanide (1.93 g, 37.8
mmol) in acetic acid (20 mL). This mixture was cooled to 0.degree.
C. and stirred at that temperature as sulfuric acid (20 mL) was
slowly added. The reaction, which turned a deep red color upon
complete addition of reagents, was stirred at ambient temperature
for 18 h. It was then quenched with the addition of 100 mL water,
made basic (pH 9) by addition of 3 M aqueous sodium hydroxide, and
extracted with dichloromethane (4.times.50 mL). The combined
organic layers were dried over anhydrous sodium sulfate and
concentrated to obtain an off-white solid. The solid was dissolved
in dry THF (200 mL), cooled to 0.degree. C. and held at this
temperature as a solution of lithium aluminum hydride (25.2 mL of 2
M in THE, 50.4 mmol) was slowly added. The reaction was heated to
reflux for 18 h, cooled in ice-bath, and quenched by cautious
addition of 5 g of sodium sulfate decahydrate. The resulting
mixture was stirred for 30 min and filtered. The filtrate was
concentrated, and the residue was purified on 120 g silica gel
column, using 0-70% CMA in chloroform, providing
N,3-dimethylspiro[bicyclo[2.2.2]oct[5]ene-2,1'-cyclopentan]-3-amine
(0.20 g, 2.7% yield). This material was taken up in dichloromethane
(5 ml), converted to the HCL salt by treating with 0.5 mL of 4 M
hydrochloric acid in dioxane and concentrating the resulting
mixture. The resultant amorphous solid was dissolved in methanol (3
mL) and precipitated with diethyl ether (3 mL). The solvent was
removed by aspiration, and the precipitate was triturated three
times with diethyl ether (3 mL), The sample of hydrochloride salt
was then vacuum dried. .sup.1H NMR (300 MHz, CD.sub.3OD) .delta.
1.02 (s, 3H), 1.19-1.42 (m, 4H), 1.51-1.64 (m, 7H), 1.81 (m, 1H),
2.21 (m, 2H), 2.73 (s, 3H), 5.57 (dd, J=9 Hz, J.sub.2=3 Hz, 1H),
6.01 (d, J=6 Hz, 1H); LCMS (m/z): 206 (M+1).
[0129]
N,3-dimethylspiro[bicyclo[2.2.2]oct[5]ene-2,1'-cyclopentan]-3-amine
(80 mg, 0.39 mmol) was dissolved in methanol (7.8 mL) and 10% Pd/C
(wet) (41 mg) was added. This mixture was placed under a balloon of
hydrogen gas and stirred at ambient temperature for 16 h. The
reaction mixture was then filtered through diatomaceous earth, and
the filtrate was concentrated, leaving
N,3-dimethylspiro[bicyclo[2.2.2]octane-2,1'-cyclopentan]-3-amine
(45 mg, 56% yield). This was dissolved in dichloromethane (3 mL),
converted to its hydrochloric acid salt by treating with 0.3 mL of
4 M hydrochloric acid in dioxane, and concentrating the resulting
mixture. The resultant amorphous solid was dissolved in methanol (3
mL) and precipitated with diethyl ether (1 mL). The solvent was
removed by aspiration, and the precipitate was triturated three
times with diethyl ether (3 mL). The sample of hydrochloride salt
was then vacuum dried. .sup.1H NMR (300 MHz, CD.sub.3OD) .delta.
0.99 (s, 3H), 1.31 (m, 2H), 1.45-1.70 (m, 10H), 1.85 (m, 1H), 2.08
(m, 3H), 2.22-2.35 (m, 1H), 2.65 (s, 3H), 3.02 (m, 1H); LCMS (m/z):
208 (M+1).
VI. Biological Assays
Characterization of Interactions at Nicotinic Acetylcholine
Receptors Materials and Methods
[0130] Cell Lines.
[0131] SH-EP1-human .alpha.4.beta.2 (Eaton et al., 2003),
SH-EP1-human .alpha.4.beta.4 (Gentry et al., 2003) and
SH-EP1-.alpha.6.beta.3.beta.4.alpha.5 (Grinevich et al., 2005) cell
lines were obtained from Dr. Ron Lukas (Barrow Neurological
Institute). The SH-EP1 cell lines, PC12, SH-SY5Y and TE671/RD cells
were maintained in proliferative growth phase in Dulbecco's
modified Eagle's medium (Invitrogen, Carlsbad, Calif.) with 10%
horse serum (Invitrogen), 5% fetal bovine serum (HyClone, Logan
Utah), 1 mM sodium pyruvate, 4 mM L-glutamine. For maintenance of
stable transfectants, the .alpha.4.beta.2 and .alpha.4.beta.4 cell
media was supplemented with 0.25 mg/mL zeocin and 0.13 mg/mL
hygromycin B. Selection was maintained for the
.alpha.6.beta.4.alpha.5 cells with 0.25 mg/mL of zeocin, 0.13 mg/mL
of hygromycin B, 0.4 mg/mL of geneticin, and 0.2 mg/mL of
blasticidin.
Receptor Binding Assays
[0132] Preparation of Membranes from Rat Tissues.
[0133] Rat cortices were obtained from Analytical Biological
Services, incorporated (ABS. Wilmington, Del.). Tissues were
dissected from female Sprague-Dawley rats, frozen and shipped on
dry ice. Tissues were stored at -20.degree. C. until needed for
membrane preparation. Cortices from 10 rats were pooled and
homogenized by Polytron (Kinematica GmbH, Switzerland) in 10
volumes (weight:volume) of ice-cold preparative buffer (11 mM KCl,
6 mM KH.sub.2PO.sub.4, 137 mM NaCl, 8 mM Na.sub.2HPO.sub.4, 20 mM
HEPES (free acid), 5 mM iodoacetamide, 1.5 mM EDTA, 0.1 mM PMSF pH
7.4). The resulting homogenate was centrifuged at 40,000 g for 20
minutes at 4.degree. C. and the resulting pellet was re-suspended
in volumes of ice-cold water. After 60 minute incubation at
4.degree. C., a new pellet was collected by centrifugation at
40,000 g for 20 minutes at 4.degree. C. The final pellet was
re-suspended in preparative buffer and stored at -20.degree. C. On
the day of the assay, tissue was thawed, centrifuged at 40,000 g
for 20 minutes and then re-suspended in Dulbecco's Phosphate
Buffered Saline, pH 7.4 (PBS, Invitrogen) to a final concentration
of 2-3 mg protein/mL. Protein concentrations were determined using
the Pierce BCA Protein Assay kit (Pierce Biotechnology, Rockford,
Ill.), with bovine serum albumin as the standard.
[0134] Preparation of Membranes from Clonal Cell Lines.
[0135] Cells were harvested in ice-cold PBS, pH 7.4, then
homogenized with a Polytron (Kinematica GmbH. Switzerland).
Homogenates were centrifuged at 40,000 g for 20 minutes (4.degree.
C.). The pellet was re-suspended in PBS and protein concentration
determined using the Pierce BCA Protein Assay kit (Pierce
Biotechnology, Rockford, Ill.).
[0136] Competition Binding to Receptors in Membrane
Preparations.
[0137] Binding to nicotinic receptors was assayed on membranes
using standard methods adapted from published procedures (Lippiello
and Fernandes 1986; Davies et al., 1999). In brief, membranes were
reconstituted from frozen stocks and incubated for 2 h on ice in
150 .mu.l assay buffer (PBS) in the presence of competitor compound
(0.001 nM to 100 .mu.M) and radioligand. [.sup.3H]-nicotine
(L-(-)-[N-methyl-.sup.3H]-nicotine, 69.5 Ci/mmol, Perkin-Elmer Life
Sciences, Waltham, Mass.) was used for human .alpha.4.beta.2
binding studies. [.sup.3H]-epibatidine (52 Ci/mmol, Perkin-Elmer
Life Sciences) was used for binding studies at the other nicotinic
receptor subtypes. L-[Benzilic-4,4-.sup.3H] Quinuclidynyl Benzilate
([.sup.3H]QNB) was used for muscarinic receptor binding studies,
Incubation was terminated by rapid filtration on a multimanifold
tissue harvester (Brandel, Gaithersburg, Md.) using GF/B filters
presoaked in 0.33% polyethyleneimine (w/v) to reduce non-specific
binding. Filters were washed 3 times with ice-cold PBS and the
retained radioactivity was determined by liquid scintillation
counting.
[0138] Binding Data Analysis.
[0139] Binding data were expressed as percent total control
binding. Replicates for each point were averaged and plotted
against the log of drug concentration. The ICO (concentration of
the compound that produces 50% inhibition of binding) was
determined by least squares non-linear regression using GraphPad
Prism software (GraphPAD, San Diego, Calif.), Ki was calculated
using the Cheng-Prusoff equation (Cheng and Prusoff, 1973).
Calcium Flux Functional Assays
[0140] Twenty-four to forty-eight hours prior to each experiment,
cells were plated in 96 well black-walled, clear bottom plates
(Corning, Corning, N.Y.) at 60-100,000 cells/well. On the day of
the experiment, growth medium was gently removed, 200 .mu.L
1.times. FLIPR Calcium 4 Assay reagent (Molecular Devices,
Sunnyvale, Calif.) in assay buffer (20 mM HEPES, 7 mM TRIS base, 4
mM CaCl.sub.2, 5 mM D-glucose, 0.8 mM MgSO.sub.4, 5 mM KCl, 0.8 mM
MgCl.sub.2, 120 mM N-methyl D-glucamine, 20 mM NaCl, pH 7.4 for
SH-EP1-human .alpha.4.beta.2 cells or 10 mM HEPES, 2.5 mM
CaCl.sub.2, 5.6 mM D-glucose, 0.8 mM MgSO.sub.4, 5.3 mM KCl, 138 mM
NaCl, pH 7.4 with TRIS-base for all other cell lines) was added to
each well and plates were incubated at 37'C for 1 hour (29.degree.
C. for the 29.degree. C.-treated SH-EP1-human .alpha.4.beta.2
cells). For inhibition studies, competitor compound (10 pM-10
.mu.M) was added at the time of dye addition. The plates were
removed from the incubator and allowed to equilibrate to room
temperature. Plates were transferred to a FLIPR Tetra fluorometric
imaging plate reader (Molecular Devices) for addition of compound
and monitoring of fluorescence (excitation 485 nm, emission 525
nm). The amount of calcium flux was compared to both a positive
(nicotine) and negative control (buffer alone). The positive
control was defined as 100% response and the results of the test
compounds were expressed as a percentage of the positive control.
For inhibition studies, the agonist nicotine was used at
concentrations of 1 pM for SH-EP1-human .alpha.4.beta.2 and
SH-EP1-human .alpha.4.beta.4 cells, 10 .mu.M for PC12 and SH-SYSY
cells, and 100 .mu.M for TE671/RD cells.
Neurotransmitter Release
[0141] Dopamine release studies were performed using striatal
synaptosomes obtained from rat brain as previously described
(Bencherif et al., 1998). Striatal tissue from two rats (female,
Sprague-Dawley, weighing 150-250 g) was pooled and homogenized in
ice-cold 0.32 M sucrose (8 mL) containing 5 mM HEPES, pH 7.4, using
a glass/glass homogenizer. The tissue was then centrifuged at
1,000.times.g for 10 minutes. The pellet was discarded and the
supernatant was centrifuged at 12,500.times.g for 20 minutes. The
resulting pellet was re-suspended in ice-cold perfusion buffer
containing monoamine oxidase inhibitors (128 mM NaCl, 1.2 mM
KH.sub.2PO.sub.4, 2.4 mM KCl, 3.2 mM CaCl.sub.2, 1.2 mM MgSO.sub.4
25 mM HEPES, 1 mM ascorbic acid, 0.02 mM pargyline HCl and 10 mM
glucose, pH 7.4) and centrifuged for 15 minutes at 23,000.times.g.
The final pellet was re-suspended in perfusion buffer (2 mL) for
immediate use.
[0142] The synaptosomal suspension was incubated for 10 minutes in
a 37'C shaking incubator to restore metabolic activity.
[.sup.3H]Dopamine ([.sup.3H]DA, specific activity=28.0 Ci/mmol, NEN
Research Products) was added at a final concentration of 0.1 pM and
the suspension was incubated at 37.degree. C. for another 10
minutes. Aliquots of perfusion buffer (100 .mu.L) and tissue (100
.mu.L) were loaded into the suprafusion chambers of a Brandel
Suprafusion System (series 2500, Gaithersburg, Md.). Perfusion
buffer (room temperature) was pumped into the chambers at a rate of
approximately 0.6 mL/min for a wash period of 8 min. Competitor
compound (10 pM-100 nM) was applied in the perfusion stream for 8
minutes. Nicotine (10 pM) was then applied in the perfusion stream
for 48 seconds. Fractions (12 seconds each) were continuously
collected from each chamber throughout the experiment to capture
basal release and agonist-induced peak release and to re-establish
the baseline after the agonist application. The perfusate was
collected directly into scintillation vials, to which scintillation
fluid was added. Released [.sup.3H]DA was quantified by
scintillation counting. For each chamber, the integrated area of
the peak was normalized to its baseline.
[0143] Release was expressed as a percentage of release obtained
with control nicotine in the absence of competitor. Within each
assay, each test compound concentration was replicated using 2
chambers; replicates were averaged. The compound concentration
resulting in half maximal inhibition (IC.sub.50) of specific ion
flux was defined.
Patch Clamp Electrophysiology
[0144] Cell Handling.
[0145] After removal of GH4C1-rat T6'S .alpha.7 cells from the
incubator, medium was aspirated, cells trypsinized for 3 minutes,
gently triturated to detach them from the plate, washed twice with
recording medium, and re-suspended in 2 ml of external solution
(see below for composition). Cells were placed in the Dynaflow chip
mount on the stage of an inverted Zeiss microscope (Carl Zeiss
Inc., Thornwood, N.Y.). On average, 5 minutes was necessary before
the whole-cell recording configuration was established. To avoid
modification of the cell conditions, a single cell was recorded per
single load. To evoke short responses, compounds were applied for
0.5 s using a Dynaflow system (Cellectricon, Inc., Gaithersburg,
Md.), where each channel delivered pressure-driven solutions at
either 50 or 150 psi.
[0146] Electrophysiology.
[0147] Conventional whole-cell current recordings were used. Glass
microelectrodes (5-10 MD resistance) were used to form tight seals
(>1 G.OMEGA.) on the cell surface until suction was applied to
convert to conventional whole-cell recording. The cells were then
voltage-clamped at holding potentials of -60 mV, and ion currents
in response to application of ligands were measured. Whole-cell
currents recorded with an Axon 700A amplifier were filtered at 1
kHz and sampled at 5 kHz by an ADC board 1440 (Molecular Devices).
Whole-cell access resistance was less than 20 MD, Data acquisition
of whole-cell currents was done using a Clampex 10 (Molecular
Devices, Sunnyvale, Calif.), and the results were plotted using
Prism 5.0 (GraphPad Software Inc., San Diego, Calif.). The
experimental data are presented as the mean.+-.S.E.M., and
comparisons of different conditions were analyzed for statistical
significance using Student's t and Two Way ANOVA tests. All
experiments were performed at room temperature (22.+-.1.degree.
C.). Concentration-response profiles were fit to the Hill equation
and analyzed using Prism 5.0.
[0148] Solutions and Drug Application.
[0149] The standard external solution contained: 120 mM NaCl, 3 mM
KCl, 2 mM MgCl.sub.2, 2 mM CaCl.sub.2, 25 mM D-glucose, and 10 mM
HEPES and was adjusted to pH 7.4 with Tris base. Internal solution
for whole-cell recordings consisted of: 110 mM Tris phosphate
dibasic, 28 mM Tris base, 11 mM EGTA, 2 mM MgCl.sub.2, 0.1 mM
CaCl.sub.2, and 4 mM Mg-ATP, pH 7.3. (Liu et al., 2008). To
initiate whole-cell current responses, compounds were delivered by
moving cells from the control solution to agonist-containing
solution and back so that solution exchange occurred within
.about.50 ms (based on 10-90% peak current rise times). Intervals
between compound applications (0.5-1 min) were adjusted
specifically to ensure the stability of receptor responsiveness
(without functional rundown), and the selection of pipette
solutions used in most of the studies described here was made with
the same objective. (-)-Nicotine and acetylcholine (ACh), were
purchased from Sigma-Aldrich (St. Louis, Mo.). All drugs were
prepared daily from stock solutions.
[0150] To determine the inhibition of ACh induced currents by
compounds of the present invention, we established a stable
baseline recording applying 70 .mu.M ACh (usually stable 5-10
consecutive applications). Then ACh (70 .mu.M) was co-applied with
test compound in a concentration range of 1 nM to 10 .mu.M. Since
tail of the current (current measured at the end of 0.5 s ACh
application) underwent the most profound changes, inhibition and
recovery plots represent amplitude of tail current.
Tabulated Summary
[0151] As shown in Table 1, compounds representative of the present
invention typically exhibit inhibition constants (Ki values) for
human .alpha.4.beta.2 and ganglionic receptor subtypes in the 1-100
mM range, indicating a low affinity for the orthosteric binding
sites (i.e. the binding site of the competitive agonist) of these
receptor subtypes. The data in Table 1, however, also illustrates
that compounds representative of the present invention effectively
inhibit ion flux for these receptor subtypes, with typical
IC.sub.50 values of less than about 2 mM and typical I.sub.max
values of >95%. Taken together, this data demonstrates that the
compounds representative of this invention are effective at
inhibiting ion flux mediated by these receptor subtypes through a
mechanism that does not involve binding at the orthosteric
sites.
TABLE-US-00001 TABLE 4 Human Human Human Human Human
.alpha.4.beta.2 Ca .alpha.4.beta.2 Ca .alpha.4.beta.2 Ca
.alpha.4.beta.2 Ca Human Ganglion Human Human Flux IC50 Flux Imax
Flux IC50 Flux Imax Ganglion Ca Ca .alpha.4.beta.2 Ki Ganglion Ki
[29C/HS] [29C/HS] (% [37C/LS] [37C/LS] (% Flux IC50 Flux Imax
Structure (nM) (nM) (nM) inh) (nM) inh) (nM) (% inh) ##STR00005##
>10,000 >10,000 1000 99 500 97 160 97 ##STR00006## 3800
>10,000 1400 99 59 96 190 79 ##STR00007## 10,000 >10,000 1400
96 740 98 190 89 ##STR00008## 2600 >10,000 1800 98 620 98 230 98
##STR00009## 540 >10,000 2100 97 570 93 440 93 ##STR00010## 8700
>10,000 610 98 230 95 98 93 ##STR00011## >10,000 >10,000
210 98 97 96 23 100 ##STR00012## >10,000 >10,000 260 98 65 94
40 98 ##STR00013## >10,000 >10,000 1300 99 490 96 180 97
##STR00014## 5600 >10,000 710 98 430 96 74 99 ##STR00015##
>10,000 >10,000 1000 97 600 96 98 95 ##STR00016## >10,000
>10,000 310 97 270 93 60 97 ##STR00017## >10,000 >10,000
540 96 520 97 100 98 ##STR00018## >10,000 >10,000 140 96 350
95 66 97 ##STR00019## 3200 >10,000 1100 96 280 95 65 95
##STR00020## 2600 >10,000 740 95 380 95 86 99 ##STR00021##
>10,000 >10,000 1100 99 120 100 35 96 ##STR00022## >10,000
>10,000 380 97 120 93 170 98 ##STR00023## 3000 >10,000 400 95
240 92
[0152] The specific pharmacological responses observed may vary
according to and depending on the particular active compound
selected or whether there are present pharmaceutical carriers, as
well as the type of formulation and mode of administration
employed, and such expected variations or differences in the
results are contemplated in accordance with practice of the present
invention.
[0153] Although specific embodiments of the present invention are
herein illustrated and described in detail, the invention is not
limited thereto. The above detailed descriptions are provided as
exemplary of the present invention and should not be construed as
constituting any limitation of the invention. Modifications will be
obvious to those skilled in the art, and all modifications that do
not depart from the spirit of the invention are intended to be
included with the scope of the appended claims.
* * * * *