Bicyclic and tricyclic heteroaromatic compounds

Details Bicyclic and tricyclic heteroaromatic compounds Bicyclic and tricyclic heteroaromatic compounds

2000-11-10

2003-01-28

Shah, Mukund J. (Department: 1624)

Drug, bio-affecting and body treating compositions

Designated organic active ingredient containing

Having -c-, wherein x is chalcogen, bonded directly to...

C546S085000, C546S086000, C546S087000, C544S333000, C544S405000, C514S255050, C514S256000

Reexamination Certificate

active

06511987

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to heterocyclic derivatives that bind to the benzodiazepine site of GABA
A
receptors. This invention also relates to pharmaceutical compositions comprising such compounds and to the use of such compounds in the treatment of central nervous system (CNS) diseases. This invention also relates to the use of these heterocyclic compounds in combination with one or more other CNS agents to potentiate the effects of the other CNS agents. Additionally this invention relates to the use such compounds as probes for the localization of GABA
A
receptors in tissue sections.
BACKGROUND
The GABA
A
receptor superfamily represents one of the classes of receptors through which the major inhibitory neurotransmitter, &ggr;-aminobutyric acid, or GABA, acts. Widely, although unequally, distributed through the mammalian brain, GABA mediates many of its actions through a complex of proteins called the GABA
A
receptor, which causes alteration in chloride conductance and membrane polarization.
A number of cDNAs for GABA
A
receptor subunits have been characterized. To date at least 6&agr;, 3&bgr;, 3&ggr;, 1&egr;, 1&dgr; and 2&pgr; subunits have been identified. It is generally accepted that native GABA
A
receptors are typically composed of 2&agr;, 2&bgr;, and 1&ggr; subunits (Pritchett & Seeburg
Science
1989; 245:1389-1392 and Knight et. al.,
Recept. Channels
1998; 6:1-18). Evidence such as message distribution, genome localization and biochemical study results suggest that the major naturally occurring receptor combinations are &agr;
1
&bgr;
2
&ggr;
2
, &agr;
2
&bgr;
3
&ggr;
2
, &agr;
3
&bgr;
3
&ggr;
2
, and &agr;
5
&bgr;
3
&ggr;
2
(Mohler et. al. Neuroch. Res. 1995; 20(5): 631-636).
Benzodiazepines exert their pharmacological actions by interacting with the benzodiazepine binding sites associated with the GABA
A
receptor. In addition to the benzodiazepine site, the GABA
A
receptor contains sites of interaction for several other classes of drugs. These include a steroid binding site, a picrotoxin site, and the barbiturate site. The benzodiazepine site of the GABA
A
receptor is a distinct site on the receptor complex that does not overlap with the site of interaction for GABA or for other classes of drugs that bind to the receptor (see, e.g., Cooper, et al., The Biochemical Basis of Neuropharmacology, 6
th ed.,
1991, pp. 145-148, Oxford University Press, New York). Early electrophysiological studies indicated that a major action of the benzodiazepines was enhancement of GABAergic inhibition. Compounds that selectively bind to the benzodiazepine site and enhance the ability of GABA to open GABA
A
receptor channels are agonists of GABA receptors. Other compounds that interact with the same site but negatively modulate the action of GABA are called inverse agonists. Compounds belonging to a third class bind selectively to the benzodiazepine site and yet have little or no effect on GABA activity, but can block the action of GABA
A
receptor agonists or inverse agonists that act at this site. These compounds are referred to as antagonists.
The important allosteric modulatory effects of drugs acting at the benzodiazepine site were recognized early and the distribution of activities at different receptor subtypes has been an area of intense pharmacological discovery. Agonists that act at the benzodiazepine site are known to exhibit anxiolytic, sedative, and hypnotic effects, while compounds that act as inverse agonists at this site elicit anxiogenic, cognition enhancing, and proconvulsant effects. While benzodiazepines have a long history of pharmaceutical use as anxiolytics, these compounds often exhibit a number of unwanted side effects. These may include cognitive impairment, sedation, ataxia, potentiation of ethanol effects, and a tendency for tolerance and drug dependence.
GABA
A
selective ligands may also act to potentiate the effects of other CNS active compounds. For example, there is evidence that selective serotonin reuptake inhibitors (SSRIs) may show greater antidepressant activity when used in combination with GABA
A
selective ligands than when used alone.
SUMMARY OF THE INVENTION
This invention provides heterocyclic derivatives, particularly imidazoquinoline and 1,2,4-triazoloquinoline derivatives, that bind to the benzodiazepine site of the GABA
A
receptor, including human GABA
A
receptors. Preferably, these compounds also bind with high affinity to such receptors. More preferably, these compounds bind with high selectivity to such receptors.
The invention provides compounds of Formula I (shown below), and pharmaceutical compositions comprising compounds of Formula 1.
The invention further provides methods of treating patients suffering from CNS disorders with a therapeutically effective amount of a compound of the invention. The patient may be a human or other mammal. Treatment of humans, domesticated companion animals (pets) and livestock animals suffering from CNS disorders with a therapeutically effective amount of a compound of the invention is contemplated by the invention.
In a separate aspect, the invention provides a method of potentiating the actions of other CNS active compounds. This method comprises administering a therapeutically effective amount of a compound of the invention with another CNS active compound.
Additionally this invention provides for the use of the compounds of the invention as probes for the localization of GABA
A
receptors in tissue samples, in particular, tissue sections.
The invention also provides intermediate compounds that are useful in the preparation of compounds of Formula 1.
A broad aspect of the invention is directed to compounds of Formula 1:
And the pharmaceutically acceptable salts thereof, wherein:
X represents N or CR
1
, wherein
R
1
is hydrogen, halogen, hydroxy, cyano, nitro, amino, C
1
-C
6
alkyl, C
1
-C
6
alkoxy, trifluoromethyl, trifluoromethoxy, mono or di(C
1
-C
6
)alkylamino, or amino(C
1
-C
6
)alkyl;
X
1
represents N, CH, or C
1
-C
6
alkyl;
Y and Z are independently hydrogen, halogen, hydroxy, cyano, nitro, amino, C
1
-C
6
alkyl, C
1
-C
6
alkoxy, trifluoromethyl, trifluoromethoxy, mono or di(C
1
-C
6
)alkylamino, or amino(C
1
-C
6
)alkyl; or
Y and Z together form an arylene ring or a C
3
-C
8
cycloalkylene ring, each of which is optionally substituted with up to four groups R
2
independently chosen at each occurrence from halogen, hydroxy, cyano, nitro, amino, C
1
-C
6
alkyl, C
1
-C
6
alkoxy, trifluoromethyl, trifluoromethoxy, mono or di(C
1
-C
6
)alkylamino, and amino(C
1
-C
6
) alkyl;
W is aryl or heteroaryl, each of which is optionally substituted with one or more groups R
A
, wherein each R
A
is independently
i) halogen, hydroxy, cyano, nitro, amino, C
1
-C
6
alkoxy, trifluoromethyl, trifluoromethoxy, —SO
2
NH
2
, —SO
2
NH(C
1
-C
8
alkyl), —SO
2
N(C
1-8
alkyl)(C
1
-C
8
alkyl), —NH(C
1
-C
8
alkyl), —N(C
1
-C
8
alkyl) (C
1-8
alkyl), —N(C
1
-C
8
alkyl)CO(C
1
-C
8
alkyl), —N(C
1
-C
8
alkyl)CO
2
(C
1
-C
8
alkyl), —CONH
2
, —CONH(C
1
-C
8
alkyl), —CON(C
1
-C
8
alkyl) (C
1
-C
8
alkyl), —CO
2
(C
1
-C
8
alkyl), —S(C
1
-C
8
alkyl), —SO(C
1
-C
8
alkyl), or —SO
2
(C
1
-C
8
alkyl);
ii) aryl or heteroaryl, each of which is optionally substituted with one or two groups independently selected from halogen, hydroxy, cyano, nitro, amino, C
1
-C
6
alkyl, C
1
-C
6
alkoxy, trifluoromethyl, trifluoromethoxy, mono or di(C
1
-C
6
)alkylamino, and amino (C
1
-C
6
) alkyl;
iii) C
1
-C
8
alkyl, C
2
-C
8
alkenyl, C
2
-C
8
alkynyl, C
3
-C
8
cycloalkyl, C
3
-C
8
cycloalkyl (C
1
-C
3
alkyl), C
3
-C
8
cycloalkenyl, each of which is unsubstituted or substituted by one or more substituents independently selected from hydroxy, oxo, halogen, C
1
-C
6
alkoxy, —CONH
2
, —CONHC
1
-C
6
alkyl, —CON(C
1
-C
6
alkyl) (C
1
-C
6
alkyl), —COOH, and —CO
2
C
1
-C
6
alkyl; or
iv) NR
4
R
5
, wherein R
4
, R
5
and the nitrogen to which they are attached form a monocyclic or bicyclic ring optionally containing one or more of oxo, O, S, SO, SO
2
, or NR
6
wherein R
6
is hydrogen, C
1
-C
6
al

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