WO2002036562A2

WO2002036562A2 - 1-aryl- or 1-alkylsulfonyl-heterocyclylbenzazoles as 5-hydroxytryptamine-6 ligands

Info

Publication number: WO2002036562A2
Application number: PCT/US2001/045389
Authority: WO
Inventors: Michael Gerard Kelly; Derek Cecil Cole
Original assignee: Wyeth
Priority date: 2000-11-02
Filing date: 2001-10-31
Publication date: 2002-05-10
Also published as: PL213134B1; TWI282787B; JP2004513111A; AU2005102A; US20040132741A1; NO326610B1; IL155443A0; BR0115102B1; KR100822655B1; EP2298738A1; CA2426031C; PL362138A1; NZ525592A; CN1222511C; MXPA03003800A; NO20031977D0; US20020115670A1; IL155443A; KR20030040566A; EA006205B1

Abstract

The present invention provides a compound of formula (I) and the use thereof in the therapeutic treatment of disorders related to or affected by the 5-HT6 receptor.

Description

1-ARYL- OR 1-ALKYLSULFO Y -HETEROCYCLY BENZAZOLES AS 5-HYDROXYTRYPTAMINE- 6 LIGANDS

This invention relates to 1-Aryl- or 1- alkylsulfonyl-heterocyclylbenzazoles useful as 5- hydroxytryptamine-6 ligands, to processes for preparing them, to pharmaceutical compositions containing them and to methods of treatment using them.

BACKGROUND OF THE INVENTION

Compounds capable of forming 5-HT6 receptor ligands are potentially useful in the treatment of a number of central nervous system disorders such as anxiety, depression, epilepsy obsessive compulsive disorders, migraine, cognitive disorders, sleep disorders, feeding disorders, panic attacks, disorders resulting from withdrawal from drug abuse, schizophrenia, or certain gastrointestinal disorders such as irritable bowel syndrome. Significant efforts are being made to understand the recently identified 5HT-6 receptor and its possible role in neuropsychiatric and neurodegenerative functions. To that end, new compounds which demonstrate a binding affinity for the 5HT-6 receptor are earnestly sought, particularly as potential potent therapeutic agents .

Therefore, it is an object of this invention to provide compounds which are useful as therapeutic agents in the treatment of a variety of conditions related to or affected by the 5-HT6 receptor.

It is another object of this invention to provide methods and compositions useful for the treatment of psychoses (e.g., schizophrenia, anxiety, or depression), motor disorders (e.g., Parkinson's disease), anxiety, depression, obsessive compulsive disorder, attention deficit disorder, or any condition which is known to be related to or affected by the 5-HT6 receptor. These and other objects and features of this invention will become more apparent by the detailed description set forth hereinbelow.

SUMMARY OF THE INVENTION The present invention provides a compound of formula I

(I)

wherein

A is C, CRio or N;

Y is CR₇ or N with the proviso that when X is N, then

Y must be CR₇; Ri is H, Cι-C₆alkylcarbonyl, Cι-C₆alkoxycarbonyl or an

Cι-C₆alkyl, C₂-C₆alkenyl₇ C₂-C₆alkynyl or C₅-

C₇cycloheteroalkyl group each optionally substituted; R₂, R₃, R , R₅ and R₆ are each independently H, halogen, OH or an optionally substituted Ci- C₆alkyl group ; R₇ and Rn are each independently H, halogen or an Ci- C₆alkyl, aryl, heteroaryl or Cx-Cgalkoxy group each optionally substituted; R₈ is an Cχ-C₆alkyl, aryl or heteroaryl group each optionally substituted; R₉ is H, halogen or a Cι-C₃alkyl, Cx-Cealkoxy, C₂- C₆alkenyl, aryl or heteroaryl group each optionally substituted; Rio is H, OH or an optionally substituted alkoxy group; m is an integer of 1, 2 or 3 ; n is 0 or an integer of 1, 2 or 3; and represents a single bond or a double bond; or a pharmaceutically acceptable salt thereof.

The present invention also provides methods and compositions useful in the treatment of central nervous system disorders.

DETAILED DESCRIPTION OF THE INVENTION

The 5-hydroxytryptami e-6 (5-HT6) receptor is one of the most recent receptors to be identified by molecular cloning. Its ability to bind a wide range of therapeutic compounds used in psychiatry, coupled with its intriguing distribution in the brain has stimulated significant interest in new compounds which are capable of interacting with or affecting said receptor. At present, there are no known fully selective agonists. Significant efforts are being made to understand the possible role of the 5-HT6 receptor in psychiatry, cognitive dysfunction, motor function and control, memory, mood and the like. To that end, compounds which demonstrate a binding affinity for the 5-HT6 receptor are earnestly sought both as an aid in the study of the 5-HT6 receptor and as potential therapeutic agents in the treatment of central nervous system disorders .

Surprisingly, it has now been found that 1-alkyl- or 1-arylsulfonyl-heterocyclylbenzazoles of formula I demonstrate 5-HT6 affinity along with significant subtype selectivity. Advantageously, said formula I benzazoles are effective therapeutic agents for the treatment of central nervous system disorders associated with or affected by the 5-HT6 receptor. Accordingly, the present invention provides 1-alkyl- or 1-arylsulfonyl- heterocyclylbenzazole compounds of formula I

( I )

wherein

A is C , CR₁₀ or N;

X is CRu or N ; Y is CR₇ or N with the proviso that when X is N, then

Y must be CR₇; R_x is H, Cx-Cgalkylcarbonyl, Cι-C₆alkoxycarbonyl or a Cι-C₆alkyl, C₂-C₆alkenyl, C₂-C_ealkynyl or cycloheteroalkyl group each optionally substituted; R₂, R₃, R , R₅ and R₆ are each independently H, halogen, OH or an optionally substituted Ci- C₆alkyl group; R₇ and R_1X are each independently H, halogen or an O_.- C₆alkyl, aryl, heteroaryl or alkoxy group each optionally substituted; R₈ is an Cι-C₆alkyl, aryl or heteroaryl group each optionally substituted; R₉ is H, halogen or an Cι-C₆alkyl, Cι-C₆alkoxy, C₂- C₆alkenyl, aryl or heteroaryl group each optionally substituted; Rio is H, OH or an optionally substituted alkoxy group; m is an integer of 1, 2 or 3; n is O or an integer of 1, 2 or 3; and represents a single bond or a double bond; or a pharmaceutically acceptable salt thereof.

As used in the specification and claims, the term halogen designates Br, CI, I or F; the term aryl designates phenyl or naphthyl . The term cycloheteroalkyl designates a five to seven membered cycloalkyl ring system containing 1 or 2 heteroatoms, which may be the same or different, selected from N, NR, 0 or S and optionally containing one double bond, where R represents hydrogen or an optional substituent such as illustrated herein. Exemplary of the cycloheteroalkyl ring systems included in the term as designated herein are the following rings wherein Y is NR, O or S .

Similarly, as used in the specification and claims, the term heteroaryl designates a 5-10 membered aromatic ring system containing 1, 2 or 3 heteroatoms, which may be the same or different, selected from nitrogen, oxygen and sulphur. Such heteroaryl ring systems include pyrrolyl, azolyl, oxazolyl, thiazolyl, imidazolyl, furyl, thienyl, quinolinyl, isoquinolinyl, indolinyl, benzothienyl, benzofuranyl , benzisoxazolyl and the like; the term haloalkyl designates a C_nH_2n+ι group having from one to 2n+l halogen atoms which may be the same or different; and the term haloalkoxy designates an OC_nH_2n+ι group having from one to 2n+l halogen atoms which may be the same or different .

In the specification and claims, when terms such as Ci-Cgalkyl, C₂-C₆alkenyl, C₂-C₆alkynyl, C₃-C₇cycloalkyl, cycloheteroalkyl, aryl or heteroaryl are designated as being optionally substituted, the substituent groups which are optionally present may be one or more of those customarily employed in the development of pharmaceutical compounds or the modification of such compounds to influence their structure/activity, persistence, absorption, stability or other beneficial property. Specific examples of such substituents include halogen atoms, nitro, cyano, thiocyanato, cyanato, hydroxyl, alkyl, haloalkyl, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, formyl , alkoxycarbonyl , carboxyl, alkanoyl, alkylthio, alkylsulphinyl, alkylsulphonyl, carbamoyl, alkylamido, phenyl , phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or cycloalkyl groups, preferably halogen atoms or lower alkyl groups. Typically, 0-3 substituents may be present . When any of the foregoing substituents represents or contains an alkyl substituent group, this may be linear or branched and may contain up to 12, preferably up to 6, more preferably up to 4 carbon atoms

The variables A, X, Y, R_x, R₂, R₃, R , R₅, R_s, R₇, Rii, R₈, R₉, Rio may each be values that are optionally substituted by substituents as described herein.

Examples of the variables in formula (I) are each or any combination of the following:

A is C, N, or CRio wherein R_xo is as defined or illustrated herein (e.g. A is CH, C (OH) , C(0-Cι- C₆alkyl) wherein the alkyl group may be substituted by one or more of the following the same or different : halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, C -C₅-alkyl, Cι-C₆-alkoxy, haloCι-C₆-alkoxy, haloCι-C₆- alkyl, amino, Cι-C₆-alkylamino, di-Cι-C₃-alkylamino, formyl, C₂-C₇-alkoxycarbonyl, carboxyl, C₂-C₇-alkanoyl, Cι-C₆-alkylthio, Cι-C₆-alkylsulphinyl, Cι-C₃-alkyl- sulphonyl, carbamoyl, Cι-C₃-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅-C₇cycloalkyl groups) . X is N, CRii wherein R_u is as defined or illustrated herein (e.g.CRn is CH, C-aryl, C-halogen, C- (Ci-C₆alkyl) , C (0-Ci-C₆alkyl) wherein the alkyl or aryl group may each be substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, C-C₆-alkyl, Cχ~ C₆-alkoxy, haloCι-C₆-alkoxy, haloCι-C₆-alkyl, amino, C_x- Cg-alkylamino, di-Cι-C₆-alkylamino, formyl, C₂-C₇- alkoxycarbonyl , carboxyl, C₂-C₇-alkanoyl, Cι-C₆- alkylthio, Cι-C₆-alkylsulphinyl, C_x-C₆-alkylsulphonyl, carbamoyl, Cι-C₃-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅- C₇cycloalkyl groups) .

Y is N or CR₇ wherein R₇ is as defined or illustrated herein (e.g. CR₇ is CH, C-aryl, C-halogen, C- (Cι-C₆alkyl) , C (0-Ci-C₆alkyl) wherein the alkyl or aryl groups may each be substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₆-alkyl, C_x- C₆-alkoxy, haloCι-C₆-alkoxy, haloCι-C₆-alkyl, amino, C_x- C₆-alkylamino, di-Cι-C₆-alkylamino, formyl, C₂-C₇- alkoxycarbonyl, carboxyl, C₂-C₇-alkanoyl, Cι-C₆- alkylthio, C_!-C₆-alkylsulphinyl, Cι-C₆-alkylsulphonyl, carbamoyl, Cι-C_e-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅- C₇cycloalkyl groups) .

Ri is H, Cι-C₆alkylcarbonyl, Cι-C₆alkyloxycarbonyl or an Cι-C₆alkyl, Cι-C₆alkenyl, Cι-C₆alkynyl or 5-7 membered cycloheteroalkyl group each optionally substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C_e-alkyl, Ci-Cg-alkoxy, haloCι-C₆-alkoxy, haloCι-C₆-alkyl, amino, Cχ~ C₆-alkylamino, di- (Cι-C_e-alkyl) amino, formyl , C₂- C₇alkoxycarbonyl , carboxyl, C₂-C₇-alkanoyl, Cι-C_ε- alkylthio, Cι-C₃-alkylsulphinyl, Cι-C₃alkylsulphonyl, carbamoyl, Cι-C₆-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅-C₇cycloalkyl groups) ; said phenyl, phenoxy, benzyl and benzyloxy groups being optionally substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₆-alkyl, Cι-C₆-alkoxy, haloCι-C₆-alkoxy, haloCι-C₃-alkyl, amino, Cι-C₆-alkylamino, di- (Cι-C₆-alkyl) amino, formyl, C₂-C₇alkoxycarbonyl, carboxyl, C₂-C₇-alkanoyl , Cι-C₆-alkylthio, Cι-C₆- alkylsulphinyl, Cι-C₆alkylsulphonyl , carbamoyl, Cι-C₆- alkylamido.

R₂, R₃, R₄, R₅ and R_s are each selected from H, halogen OH or Cι-C₆alkyl wherein the alkyl group may be substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₅-alkyl, Cι-C₆-alkoxy, haloCι-C₆-alkoxy, haloCι-C₆-alkyl, amino, Cι-C₆-alkylamino, di-Cι~C₆- alkylamino, formyl, C₂-C₇-alkoxycarbonyl, carboxyl, C - C₇-alkanoyl, Cι-C₆-alkylthio, Ci-Cε-alkylsulphinyl, C - C₆-alkylsulphonyl, carbamoyl, Cι-C₆-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅-C₇cycloalkyl groups) .

R₇ and Rn are each independently H, halogen, aryl, heteroaryl, Cι-C₆alkyl or 0-Ci-C₆alkyl wherein the alkyl , aryl or heteroaryl groups may each be substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₆-alkyl, Ci-Cg-alkoxy, haloCι-C₆-alkoxy, haloCι-C₆-alkyl, amino, C -C₆-alkylamino, di-Cι-C₆- alkylamino, formyl, C₂-C₇-alkoxycarbonyl, carboxyl, C₂- C₇-alkanoyl, Cι-C₆-alkylthio, C_!-C₆-alkylsulphinyl, d_.- C_ε-alkylsulphonyl, carbamoyl, Cι-C₆-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅-C₇cycloalkyl groups) .

R₈ is a Cι-C₆alkyl, aryl or heteroaryl wherein the alkyl, aryl or heteroaryl groups may each be substituted by one or more of the following the same or different : halogen, ni'tro, cyano, thiocyanato, cyanato, hydroxyl, Ci- C₆-alkyl, d-C₆-alkoxy, haloCι-C₆-alkoxy, haloCi-C₆-alkyl , amino, Cι-C₆-alkylamino, di-Cι-C₆-alkylamino, formyl, C₂- C₇-alkoxycarbonyl, carboxyl, C₂-C₇-alkanoyl, Cι-C₆- alkylthio, Cι-C₆-alkylsulphinyl, Cι-C₆-alkylsulphonyl, carbamoyl, Ci-C_e-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅-C₇cycloalkyl groups); said phenyl, phenoxy, benzyl and benzyloxy groups being optionally substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₆-alkyl, Cι-C₆-alkoxy, haloCι-C₆-alkoxy, haloCι-C₆-alkyl, amino, C-C₆-alkylamino, di- (Ci-C₃-alkyl) amino, formyl, C₂-C₇alkoxycarbonyl, carboxyl, C₂-C₇-alkanoyl, Cι-C₆-alkylthio, Cι-C₆- alkylsulphinyl, Cι-C₃alkylsulphonyl, carbamoyl, Cι-C₆- alkylamido.

R₉ is H, halogen, aryl, heteroaryl, C₂-C₆alkenyl, Cι-C₆alkyl or 0-Cι-C₆alkyl wherein the alkenyl, alkyl, aryl or heteroaryl groups may each be substituted by one or more of the following the same or different : halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₆-alkyl, Cι-C₆-alkoxy, haloCι-C₆-alkoxy, haloC -C_e- alkyl, amino, Cι-C₆-alkylamino, di-Cι-C₆-alkylamino, formyl, C₂-C₇-alkoxycarbonyl, carboxyl, C₂-C₇-alkanoyl, Ci-Cg-alkylthio, Ci-C₆-alkylsulphinyl , Cι-C₆- alkylsulphonyl, carbamoyl, Cι-C₃-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅-C₇cycloalkyl groups) .

, Rio is H, OH or 0-Ci-C₆alkyl wherein the alkyl, group may be substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₆-alkyl, Cι-C₆- alkoxy, haloCι-C₆-alkoxy, haloC -C₆-alkyl, amino, Cι-C₆- alkylamino, di-Cι-C₆-alkylamino, formyl, C₂-C₇- alkoxycarbonyl, carboxyl, C₂-C₇-alkanoyl, Cι-C₆- alkylthio, d-C₆-alkylsulphinyl, C_x-C₃-alkylsulphonyl , carbamoyl, Cι-C₆-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, heteroaryl, cycloheteroalkyl or C₅-C₇cyclo- alkyl groups) .

More particularly, independent examples of the variables in formula (I) are each of the following:

A may represent N, CH, C (OH) , C (0-Ci-C₆alkyl) wherein the alkyl group may be substituted by one or more of the following the same or different: halogen, hydroxyl, Ci-Cg-alkoxy, amino, Cι-C₆-alkylamino, di-Ci- C₆-alkylamino and phenyl.

X may represent N or CH, C-aryl, C-halogen, C- (C_x- C₆alkyl) or C (0-Cι-C₆alkyl) .

Y may represent N or CH, C-aryl, C-halogen, C- (Ci- C₆alkyl) , C (0-Cι-C₆alkyl) . R may represent H, (Cι-C₆alkyl) carbonyl, C₅-C₇- cycloheteroalkyl having 1 or 2 nitrogen ring atoms, or an Cι-C₃ alkyl, phenylCι-C₃ alkyl, pyridylCι-C₆alkyl , thienylCι-C₆alkyl group each optionally substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₆-alkyl, Ci-Cg-alkoxy, haloCι-C_e-alkoxy, haloCι-C₃-alkyl, amino, C_x- C₆-alkylamino, di- (Cι-C₃-alkyl) amino, formyl, C₂- Calkoxycarbonyl , carboxyl, C₂-C₇-alkanoyl, Cι-C₆- alkylthio, Cι-C₆-alkylsulphinyl, Cι-C₆alkylsulphonyl , carbamoyl, Cι-C₆-alkylamido, phenyl, phenoxy, benzyl, benzyloxy, cycloheteroalkyl or C₅-C₇cycloalkyl groups.

R₂, R₃, R , R₅ and R₆ may each independently represent H, halogen, OH or -Cι-C₆alkyl.

R₈ may represent a Cι-C₆alkyl, aryl of 6-10 carbon atoms or mono- or bi-cyclic heteroaryl 6-10 carbon atoms or heteroaryl of 5-10 ring members having 1-3 heteroatoms selected from O, N and S wherein the aryl or heteroaryl groups may each be substituted by one or more of the following the same or different: halogen, nitro, cyano, thiocyanato, cyanato, hydroxyl, Cι-C₆-alkyl, Cι-C₆-alkoxy, haloCι-C₆-alkoxy, haloCι-C₆-alkyl, amino, Cι-C₆-alkylamino, di-Cι-C₆-alkylamino, formyl, C₂-C₇-alkoxycarbonyl, carboxyl, C₂-C₇-alkanoyl, Cι-C₃-alkylthio, Cι-C₆- alkylsulphinyl, Ci-C₆-alkylsulphonyl , carbamoyl, Cι-C₆- alkylamido, phenyl, phenoxy, benzyl, benzyloxy, cycloheteroalkyl or C₅-C₇cycloalkyl groups) ;

R₉ may represent H, halogen, Ci-Cgal yl Rio may represent H, OH or 0-Cι-C₆alkyl . Further examples of R_x are hydrogen, Cι-C₆alkyl

(e.g. propyl) ; (Cι-C₅alkyl) -CO- (e.g. acetyl); benzyl; phenethyl; phenpropyl; pyridylmethyl (e.g. 3- or 4- pyridylmethyl) ; thienylmethyl ; , benzoyl (Cι-C) alkyl, phenoxy (C_x-C₄) alkyl and 4 , 5-dihydro-lH-imidazolyl ; which groups may be substituted by one or more substituents the same or different such as substituents selected ■ from halogen (e.g. 2-chloro-5-thienylmethyl,

2- (p-fluorophenoxy) ethyl, p-fluorobenzoylpropyl) ; nitro (e.g. 3-nitrobenzyl) ; or (Cι-C₆) alkoxy (e.g. 3- methoxybenzyl) .

Further examples of R₈ are phenyl, naphthyl and heteroaryl groups as hereinbefore defined such as thienyl (e.g thien-2-yl) , benzothienyl (e.g benzothien- 2-yl) , i idazo [2 , 1-b] thiazolyl, benzothiazolyl, benzofurazanyl, benzothiadiazolyl, isoxazolyl, imidazolyl and pyrazolyl (e.g pyrazol-4-yl) ; which groups may each be substituted by one or more substituents (e.g 1-3) the same or different such as substituents selected from halogen, Cι-C₄ alkoxy, Cι-C alkyl, Cι-C₄ haloalkyl, Cι-C haloalkoxy C -C₄alkylamino, fi (C -C₄alkyl) amino and amino.

Examples of m are 2 and 3. R₅ and R₆ may be for example hydrogen. R₂, R₃ and R₅ may also represent hydrogen. An example of n is zero. A may be for example -N- , -CH- or -C (OH) - .

Pharmaceutically acceptable salts may be any acid addition salt formed by a compound of formula I and a pharmaceutically acceptable acid such as phosphoric, sulfuric, hydrochloric, hydrobromic, citric, maleic, succinic, fumaric, acetic, lactic, nitric, sulfonic, p-toluene sulfonic, methane sulfonic acid or the like. Preferred compounds of the invention are those compounds of formula I wherein A is N and m is 2. Also preferred are those compounds of formula I wherein R₈ is an optionally substituted phenyl group and Ri is H or a Cι-C₆alkyl or C₅-C₇cycloheteroalkyl group each optionally substituted. Further preferred compounds of the invention are those compounds of formula I wherein R₂, R₃, R₄, R₅ and R₆ are H and n is 0.

More preferred compounds of the invention are those compounds of formula I wherein A is N; m is 2 and R is H or a Cι-Calkyl or C₅-C₇cycloheteroalkyl group each optionally substituted. Another group of more preferred compounds of the invention are those compounds of formula I wherein A is N; m is 2; R_x is H or a Cι-C₄alkyl or C₅- C₇cycloheteroalkyl group each optionally substituted; and R₈ is an optionally substituted phenyl group.

Among the preferred compounds of the invention are: 1- (phenylsulfonyl) -4-piperazin-l-yl-lH-indole; 1- [ (2-bromophenyl) sulfonyl] -4-piperazin-l-yl-lH-indole; 1- [ (6-chloroimidazo [2, 1-b] [1, 3] thiazol-5-yl) sulfonyl] -4- piperazin-1-yl-lH-indole;

1- [ (3,4-dimethoxyphenyl) sulfonyl] -4-piperazin-l-yl-lH- indole; 1- [ (5-chloro-3-methyl-l-benzothien-2-yl) sulfonyl] -4- piperazin-1-yl-lH-indole; 1- [ (4-bromophenyl) sulfonyl] -4-piperazin-l-yl-lH-indole; 1- [ (5-bromothien-2-yl) sulfonyl] -4-piperazin-l-yl-lH- indole; 1- [ (4 , 5-dichlorothien-2-yl) sulfonyl] -4-piperazin-l-yl-lH- indole; methyl 4- [ (4-piperazin-l-yl-lH-indol-l-yl) sulfonyl] phenyl ether; 4-piperazin-l-yl-l-{ [4- (trifluoromethoxy) phenyl] - sulfonyl} -lH-indole; (4-benzylpiperazin-l-yl) -1- (phenylsulfonyl) -lH-indole; (4-benzylpiperazin-l-yl) -1- [ (2-bromophenyl) sulfonyl] - lH-indole; (4-benzylpiperazin-l-yl) -1- [ (6-chloroimidazo [2, 1- b] [1 , 3 ] thiazol -5 -yl ) sulfonyl] - lH-indole ; (4 -benzylpiperazin-l-yl ) - 1- [ (3 , 4 -dimethoxy- phenyl) sulfonyl] -lH-indole; [4- (3-methoxybenzyl)piperazin-l-yl] -1- (phenylsulfonyl) - lH-indole; (phenylsulfonyl) -4- [4- (pyridin-4-ylmethyl) piperazin-1- yl] -lH-indole; (phenylsulfonyl) -4- [4- (pyridin-3-ylmethyl) piperazin-1- yl] -lH-indole; (2-bromophenyl) sulfonyl] -4- [4- (3-methoxy- benzyl) piperazin-1-yl] -lH-indole; (2-bromophenyl) sulfonyl] -4- [4- (pyridin-4-yl- methyl) piperazin-1-yl] -lH-indole; (2-bromophenyl) sulfonyl] -4- [4- (pyridin-3-yl- methyl) piperazin-1-yl] -lH-indole; (phenylsulfonyl) -5-piperazin-1-yl-1H-indazole ; (phenylsulfonyl) -6-piperazin-1-yl-1H-indazole ;: (2-bromophenyl) sulfonyl] -6-piperazin-l-yl-lH-indazole; (4-bromophenyl) sulfonyl] -5-piperazin-l-yl-lH-indazole; (4-bromophenyl) sulfonyl] -6-piperazin-1-yl-lH-indazole,^■ (5-bromothien-2-yl) sulfonyl] -5-piperazin-l-yl-lH- indazole; 1- [ (5-bromothien-2-yl) sulfonyl] -6-piperazin-l-yl-lH- indazole; 1- [ (4-fluorophenyl) sulfonyl] -5-piperazin-l-yl-lH- indazole; 1- [ (4-fluorophenyl) sulfonyl] -6-piperazin-l-yl-lH- indazole; methyl 4- [ (5-piperazin-1-yl-IH-indazol-l- yl) sulfonyl] phenyl ether; 1-phenylsulfonyl-4- (4-propylpiperazin-l-yl) -IH-indazole; 1-phenylsulfonyl-4-piperazin-1-yl-lH-indazole;

1-phenylsulfonyl-4- (4-phenethylpiperazin-l-yl) -1H- indazole; 1-phenylsulfonyl-4- [4- (3 -phenylpropyl) piperazin-1-yl] -1H- indazole; and the pharmaceutically acceptable salts thereof.

This invention also provides processes for preparing compounds of formula I which processes comprises one of the following: i) reacting a compound of formula:

wherein the dotted line, n, m, R₂, R₃, R, R5, R₆, R₉, X, Y and A are as defined above and G is a protecting group, with a suphonylating agent containing the group: R₈SO₂

wherein R₈ is as defined above, and if required removing the protecting group G to give a compound of Formula I wherein R_x is hydrogen; or ii) reacting a compound of formula

wherein the dotted line, n, m, R_lΛ R₂, R₃, R₄, R₅, R_6/ R₉, X, Y and A are as defined above, with a sulphonylating agent containing the group

R₈SO₂

wherein R₈ is as defined above, to give a compound of formula (I) ;

or

iii) reacting a compound of formula I wherein Ri is hydrogen with a compound of formula :

Ri — L wherein Ri is as defined above (excepting hydrogen) and is a suitable leaving group, e.g. halogen or SMe to give a corresponding compound of formula I ; or

iv) alkylating a compound of formula (I) wherein A is CRio in which Rι₀ is OH with an alkylating agent containing the group R_a where R_a is _' optionally substituted alkyl to give a compound of formula (I) wherein Rι₀ is optionally substituted alkoxy;

or

v) converting a compound of formula (I) having a reactive substituent group to a different compound of formula I .

With regard to processes (i) and (ii) the sulphonylation may be conveniently carried out in base, e.g sodium hydride, using a sulphonylating agent such as a sulphonyl chloride of formula

R₈S0₂C1

wherein R₈ is as defined above, followed by removal of the protecting group in the case of process (i) .

Process (iii) may be conveniently carried out by using an alkylating or acylating agent with an appropriate leaving group L such as a compound of formula:

Ri hal

where Ri is optionally substituted alkyl or alkanoyl, and hal is a halogen such as chlorine. With regard to process (iv) the alkylation may conveniently be carried out in the presence of base, e.g. NaH, if desired in the presence of a solvent using an alkylating agent such as an alkyl halide.

Methods for converting reactive substituent groups in compounds of formula I to other substituent groups are well known to those skilled in the art. For example benzyl groups may be removed and replaced by hydrogen. Acetylamino groups may be converted to amino groups by hydrolysis.

In any of the reactions described herein reactive substituent groups or sites in the molecule may be protected prior to reaction by use of appropriate protecting groups inert to the reaction conditions and removing said protecting groups after the reaction .

In detail compounds of the invention may be prepared using conventional synthetic methods and, if required, standard separation and isolation techniques. For example, 4- (piperazin-1-yl) indole compounds of formula II may be readily prepared by the catalytic hydrogenation of the 4-nitroindole precursor of formula III to the corresponding 4-aminoindole of formula IV and reacting said formula IV indole with a bis-alkylating agent such as bis (2-chloroethyl) amine to give the desired formula II intermediate. The reaction is illustrated in flow diagram I . FLOW DIAGRAM I

(III) (IV) (II)

The formula II intermediate may then be converted to a compound of formula I wherein A is N, m is 2; Ri is H;

R₂, R₃, and R are H; represents a single bond; and the heterocyclyl group is in the 4 -position, by reacting the formula II intermediate with a protecting group, G, for example di-t-butyl dicarbonate, to selectively protect the piperazine basic N atom to give the compound of formula V and sequentially reacting said formula V compound with a base such as NaH and a sulfonyl chloride, R₈S0₂Cl to give the protected 4- (piperazin-1-yl) -1- (substituted-sulfonyl) indole and deprotecting said indole to give the desired compound of formula la. Reaction of said formula la compound with a reagent R_x-Hal, wherein R_x is defined hereinabove for formula I and Hal is Cl, Br or I in the presence of a base gives compounds of formula lb wherein Ri is other than H. The reaction sequence is shown in flow diagram II. FLOW DIAGRAM II

(II) (V) (la)

(lb)

Corresponding compounds of the invention wherein A is CRio may be obtained, for example, by lithiating a protected 4-bromoindole of formula VI wherein G is benzyl, and displacing the lithium group with a cyclic ketone such as an N-protected-4-piperidone to give the hydroxy intermediate of formula VII, which may then be dehydrated and sulfonylated in the manner described hereinabove to give the protected compound of formula VIII. Catalytic hydrogenation and simultaneous deprotection of said formula VIII compound gives the desired compounds of formula I wherein represents a single bond (formula Id) . The reaction sequence is shown in flow diagram III. FLOW DIAGRAM III

(VI) (VTJ)

(Id) (VTH)

These and other literature procedures may be utilized to prepare the formula I compounds of the invention. Employing a 5-, 6- or 7-haloindole, -haloindazole or -halobenzimidazole substrate as starting material and using essentially the same procedures illustrated in flow diagrams I, II and III hereinabove enables the construction of the corresponding compounds of formula I wherein the heterocyclyl group is in the 5-, 6-, or 7-position and X or Y is N. Advantageously, the inventive compound of formula I may be utilized in the treatment of central nervous system disorders relating to or affected by the 5-HT6 receptor such as motor, mood, psychiatric, cognitive, neurodegenerative or the like disorders. Accordingly, the present invention provides a method for the treatment of a disorder of the central nervous system (CNS) related to or affected by the 5-HT6 receptor in a patient in need thereof which comprises administering to said patient a therapeutically effective amount of a compound of formula I as described hereinabove. The compounds may be administered orally or parenterally or in any common manner known to be an effective administration of a therapeutic agent to a patient in need thereof. The therapeutically effective amount administered in the treatment of a specific CNS disorder may vary according to the specific condition (s) being treated, the size, age and response pattern of the patient, the severity of the disorder, the judgment of the attending physician and the like. In general, effective amounts for daily oral administration may be about 0.01 to 1,000 mg/kg, preferably about 0.5 to 500 mg/kg and effective amounts for parenteral administration may be about 0.1 to 100 mg/kg, preferably about 0.5 to 50 mg/kg. In actual practice, the compounds of the invention are administered in a solid or liquid form, either neat or in combination with one or more conventional pharmaceutical carriers or excipients. Accordingly, the present invention provides a pharmaceutical composition which comprises a pharmaceutically acceptable carrier and an effective amount of a compound of formula I as described hereinabove . Solid carriers suitable for use in the composition of the invention include one or more substances which may also act as flavoring agents, lubricants, solubilizers, suspending agents, fillers, glidants, compression aids, binders, tablet-disintegrating agents or encapsulating materials. In powders, the carrier may be a finely divided solid which is in admixture with a finely divided compound of formula I. In tablets, the formula I compound is mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. Said powders and tablets may contain up to 99% by weight of the formula I compound. Solid carriers suitable for use in the composition of the invention include calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, methyl cellulose, sodium carboxymethyl cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins.

Any pharmaceutically acceptable liquid carrier suitable for preparing solutions, suspensions, emulsions, syrups and elixirs may be employed in the composition of the invention. Compounds of formula I may be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, or a pharmaceutically acceptable oil or fat, or a mixture thereof. Said liquid composition may contain other suitable pharmaceutical additives such as solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavoring agents, suspending agents, thickening agents, coloring agents, viscosity regulators, stabilizers, osmo- regulators, or the like. Examples of liquid carriers suitable for oral and parenteral administration include water (particularly containing additives as above, e.g., cellulose derivatives, preferably sodium carboxymethyl cellulose solution) , alcohols (including monohydric alcohols and polyhydric alcohols, e.g., glycols) or their derivatives, or oils (e.g., fractionated coconut oil and arachis oil) . For parenteral administration the carrier may also be an oily ester such as ethyl oleate or isopropyl myristate.

Compositions of the invention which are sterile solutions or suspensions are suitable for intramuscular, intraperitoneal or subcutaneous injection. Sterile solutions may also be administered intravenously. Inventive compositions suitable for oral administration may be in either liquid or solid composition form. For a more clear understanding, and in order to illustrate the invention more clearly, specific examples thereof are set forth hereinbelow. The following examples are merely illustrative and are not to be understood as limiting the scope and underlying principles of the invention in any way.

Unless otherwise stated, all parts are parts by weight. The terms HPLC and NMR designate high performance liquid chromatography and nuclear magnetic resonance, respectively.

EXAMPLE 1

Preparation of 1- (Phenylsulfonyl) -4-piperazin-l-yl-lH- indole Hydrochloride

A mixture of lH-indol-4-ylpiperazine (4.0 g, 20 mmol), di-t-butyl dicarbonate (4.8 g, 22 mmol) and NaOH (0.8 g, 20 mmol) in 40% dioxane is stirred at room temperature for 10 hours and treated with water. The reaction mixture is extracted with ethyl acetate. The extracts are combined, dried over Na₂S0 and concentrated in vacuo to give t-butyl 4- (lH-indol-4-yl) piperazine-1- carboxylate as a colorless solid, mp 137°C, identified by mass spectral and elemental analyses .

A portion of the t-butyl 4- (lH-indol-1-yl) - piperazine-1-carboxylate (1.05 g, 3.5 mmol) is added to a suspension of NaH (3.8 mmol) in tetrahydrofuran at 0°C under N₂. The resultant mixture is stirred for 0.5 hr, treated with benzenesulfonyl chloride (0.616 g, 3.5 mmol) , stirred for 16 hr and treated with water. The aqueous reaction mixture is extracted with ethyl acetate. The extracts are combined, dried over Na₂S0₄ and concentrated in vacuo to give a residue. The residue is chromatographed (Si0₂, CH₂C1₂) to give t-butyl 4- (1- phenylsulfonyl- (lH-indol-4-yl) piperazine-1-carboxylate as a light yellow solid, 1.25 g (81% yield), mp 64-65°C, identified by mass spectral and elemental analyses.

A portion of the t-butyl 4- (1-benzenesulfonyl-lH- indol-4-yl) piperazine-1-carboxylate (0.85 g) is stirred in a mixture of 4N HCl and dioxane at room temperature for 2 hrs and filtered. The filtercake is dried to give the title product as a while solid, 0.64 g (99% yield) mp 60°C identified by mass spectral and NMR analyses.

EXAMPLES 2-13

Preparation of l-Arylsulfonyl-4-Piperazin-l-yl) -IH-Indole

Hydrochloride

G = protecting group

Using essentially the same procedure described in Example 1 and substituting the appropriate arylsulfonyl chloride, the following compounds listed in Table I are obtained and identified by HPLC and mass spectral analyses . TABLE I

Ex . LCMS No . R₈ Min . M+H

2 o-bromophenyl 2 . 58 422

3 6-chloroimidazo [2 , 1-b] thiazol-5-yl 2 . 48 422

4 3,4-dimethoxyphenyl 2 . 52 402

5 4 -aminopheny1

6 benzo-2, 1, 3-thiazol-4-yl

7 benzofurazan-4-yl

8 3-bromo-5-chlorothien-2-yl

9 5-chloro-3-methylbenzo (b) thien-2-yl

10 Dansyl

11 2,5-dichlorothien-3-yl

12 3, 5-dimethylisoxasol-4-yl

13 l-methylimidazol-4-yl

LCMS conditions: Hewlett Packard 1100 MSD; YMC ODS-AM 2.0 mm x 50 mm 5 u column at 23°C; 3uL injection; Solvent A: 0.02% TFA/water; Solvent B:0.02% TFA/acetonitrile; Gradient: Time 0:95% A; 0.3 min: 95% A; 4.7 min: 10% A, 4.9 min: 95% A; Post time 1 min. Flow rate 1.5 mL/min; Detection: 254 nm DAD; API-ES Scanning Mode Positive 150-700; Fragmentor 70 mV. EXAMPLE 14

Preparation of 4- [4- (4, 5-Dihydro-lH-imidazol-2-yl) piperazin-1-yl] -1- (phenylsulfonyl) -lH-indole

A solution of 1- (phenylsulfonyl) -4-piperazin-l-yl- lH-indole (71 mg, 0.18 mmol) in dioxane is treated with 2 -methylthio-2-imidazoline hydroiodide (52.7 mg, 0.22 mmol) and N,N-diisopropylethylamine (62 μl, 0.36 mmol), heated at 50°C for 16 hr., cooled and concentrated in vacuo to give a residue. The residue is purified by HPLC to give the title product, 15 mg, identified by HPLC and mass spectral analyses (2.57 min; 410 M+H) using the LCMS conditions described in Table I . EXAMPLES 15-18

Preparation of 4-Heterocyclyl-l- (arylsulfonyl) indole compounds

Using essentially the same procedure described in Example 14 and substituting the appropriate 1-

(arylsulfonyl) indole substrate, the following compounds shown in Table II are obtained and identified by HPLC and mass spectral analyses.

TABLE II

Ex. LCMS^X

No. Ra Min. M+H

5 2 -bromophenyl 2.79 490 6 6-chloroimidazo [2 , 1-b] thiazol-5-yl 2.68 490 7 3 , 4-dimethoxyphenyl 2.64 470 8 4-aminophenyl 2.46 425

LCMS conditions: same as for Table I

EXAMPLE 19

Preparation of 4- (4-Benzylpiperazin-l-yl) -1- (phenyl- sulfonyl) -lH-indole

A solution of 1- (phenylsulfonyl) -4-piperazin-l-yl- lH-indole (71 mg, 0.18 mmol) in tetrahydrofuran is treated sequentially with benzyl bromide (21 μl) and triethyl -amine (75 μl ) , shaken at room temperature for 16 hr and concentrated in vacuo to give a residue. The residue is purified by RP-HPLC to give the title product, 37 mg, identfied by HPLC and mass spectral analyses (2.81 min; 432 M+H) using the LCMS conditions described in Table I.

EXAMPLES 20-53

Preparation of 4 -Heteroaryl- 1-arylsulfonylindole compounds

Using essentially the same procedure described in Example 19 and employing the appropriate 4- (piperazin-1- yl) -1- (arylsulfonyl) indole substrate and a suitable aryl, alkyl or acyl halide, the following compounds shown in Table III are obtained and identified by HPLC and mass spectral analyses .

TABLE III

Ex. LCMS¹ No. Ri R₈ Min. M+H

0 2-chloro-5- phenyl 3.07 472 thienylmethyl 1 3 -nitrobenzyl phenyl 2.95 477 2 acetyl phenyl 3.18 384 3 benzyl 2 -bromophenyl 2.99 512 4 2-chloro-5- 2 -bromophenyl 3.08 550 thienylmethyl 5 3 -nitrobenzyl 2 -bromophenyl 3.08 550 6 acetyl 2 -bromophenyl 2.97 557 7 benzyl 6-choroimidazol [2,1- 2.91 512 b] thiazol-5-yl 8 2-chloro-5- 6-choroimidazol [2,1- 3.00 553 thienylmethyl b] thiazol-5-yl 9 3 -nitrobenzyl 6-choroimidazol [2,1- 2.87 557 b] thiazol-5-yl 0 acetyl 6-choroimidazol [2,1- 3.23 464 b] thiazol-5-yl 1 benzyl 3 , 4 -dimethoxyphenyl 2.76 492 2 2-chloro-5- 3 , 4 -dimethoxyphenyl 2.90 532 thienylmethyl TABLE III (cont ' d)

Ex. LCM S¹ No. Ri Rs Min. M+H

3 3 -nitrobenzyl 3 , 4 -dimethoxyphenyl 2.82 537 4 acetyl 3 , 4 -dimethoxyphenyl 3.10 442 5 benzyl 4 -aminophenyl 2.64 447 6 methyl 4 -aminophenyl 2.28 371 7 2-chloro-5- 4 -aminophenyl 2.82 487 thienylmethyl 8 3 -nitrobenzyl 4 -aminophenyl 2.72 492 9 3 -methoxybenzyl phenyl 2.88 462 0 -pyridylmethyl phenyl 2.40 433 1 3 -pyridylmethyl phenyl 2.42 433 2 3 -methoxybenzyl 2 -bromophenyl 2.99 542 3 4 -pyridylmethyl 2 -bromophenyl 2.51 513 4 3 -pyridylmethyl 2 -bromophenyl 2.52 513 5 3 -methoxybenzyl 6-chloroimidazo [2,1- 2.93 542 b] thiazol-5-yl 6 -pyridylmethyl 6-chloroimidazo [2, 1- 2.48 513 b] thiazol-5-yl 7 3 -pyridylmethyl 6-chloroimidazo [2, 1- 2.48 513 b] thiazol-5-yl 8 3 -methoxybenzyl 3 , 4 -dimethoxyphenyl 2.82 522 9 4 -pyridylmethyl 3 , 4 -dimethoxyphenyl 2.47 493 TABLE III (cont' d)

Ex . LCMS¹ No . Ri Rs Min. M+H

0 3 -pyridylmethyl 3 , 4 -dimethoxyphenyl 2.45 493 1 3 -methoxybenzyl 4 -aminophenyl 2.75 477 2 4 -pyridylmethyl 4 -aminophenyl 2.24 448 3 3 -pyridylmethyl 4 -aminophenyl 2.26 448

¹ LCMS conditions are the same as that for Table I

EXAMPLE 54

Preparation of 4- (Homopiperazin- 1-yl) -1- (phenylsulfonyl) benzimidazole hydrochloride

(C0₂-t-B )₂

A suspension of 4-bromobenzimidazole (42 mmol) , homopiperazine (256 mmol) and NaOt-Bu (59 mmol) in dry o- xylene, under N₂, is treated with a catalytic amount of Pd (0COCH₃)₂-P(t-Bu)₃ (P/Pd = 4), heated at 120°C for 3 hr, cooled to room temperature and diluted with water. The aqueous mixture is extracted with ethyl acetate. The extracts are combined, dried over MgS0₄ and concentrated in vacuo to give a residue. The residue is purified by flash chromotography to give 4- (homopiperazin-1- yl ) benzimidazole .

A mixture of 4- (homopiperazin- 1-yl) benzimidazole (4.3 g, 20 mmol), di-t-butyl dicarbonate (4.8 g, 22 mmol) and NaOH (0.8 g, 20 mmol) in 40% aqueous dioxane is stirred at room temperature for 10 hrs and diluted with water. The aqueous mixture is extracted with ethyl acetate. The extracts are combined, dried over NaS0₄ and concentrated in vacuo to give t-butyl 4- (benzimidazol-4- yl) homopiperazine-1-carboxylate .

A suspension of NaH (3.8 mmol) in tetrahydrofuran at 0°C, under N₂, is treated with t-butyl 4- (benzimidazol-4- yl) - homopiperazine-1-carboxylate (l.lg, 3.5 mmol), stirred for 0.5 hr, treated with benzenesulfonyl chloride (0.616 g, 3.5 mmol), stirred for 16 hours at room temperature and diluted with water. The aqueous mixture is extracted with ethyl acetate. The extracts are combined, dried over Na₂S0 and concentrated in vacuo to give a residue. The residue is purified by flash chromatography to give t-butyl 4- (1-phenylsulfonyl) -benzimidazol-4 -yl) homopiperazin-1-carboxylate .

A mixture of the thus-obtained carboxylate in 4N HCl and dioxane is stirred at room temperature for 2 hrs and filtered. The filtercake is washed with ethyl acetate and dried in vacuo to afford the title product. EXAMPLE 56

Preparation of 4- (4-Benzylpiperazin-l-yl) -lH-indazole

A stirred solution of 4 -benzyl -1- (3-fluoro-2- carboxyphenyl) -piperazine (5.96 g, 20.0 mmol) in dimethylsulfoxide (10 mL) and hydrazine (10 mL) is heated at 95°C under nitrogen for 4 days. The cooled reaction is diluted with ether and washed with a mixture of water and saturated aqueous sodium bicarbonate. The organic layer is further washed sequentially with water and brine dried over MgS0₄ and concentrated in vacuo to give a residue . The residue is chromatographed using ethyl acetate as the eluant . The resulting oil is reconcentrated from ether to give a white foam which is stirred under hexanes/ether overnight. The resulting white powder is isolated by suction filtration and washed with hexane to give the title compound 3.11 g, (53% yield), identified by HΝMR. EXAMPLE 57

Preparation of 4- (4-Benzylpiperazin-l-yl) -1- (phenylsulfonyl) -lH-indazole hydrochloride

A solution of 4- (4-benzylpiperazin-l-yl) -IH-indazole (2.34 g, 8.00 mmol) in dry dimethyl formamide is treated with 0.48 g unwashed 60% NaH in mineral oil (12.0 mmol of NaH) . After stirring under nitrogen for 15 min, the reaction is treated with benzenesulfonylchloride (1.53 mL, 12.0 mmol), stirred for 24 hr at ambient temperature, treated with saturated aqueous NaHC0₃ and water and extracted with ether. The organic layer is washed sequentially with water and brine, dried over MgS0 and concentrated in vacuo to give a residue. The residue is purified by flash chromatography on silica gel using 1:1 ethyl acetate :hexanes as eluant to afford the free amine of the title compound as an oil (3.14 g, 91%) . A portion of this oil (432 mg, 1.0 mmol) is dissolved in ether and treated with 1.0M HCl in ether (1.1 mL, 1.1 mmol) . The resulting solid is filtered, washed with ether, and dried under vacuum to provide the title compound as a light tan solid, mp 208-209°C, identified by HNMR and mass spectral analyses . EXAMPLE 58

Preparation of 1- (Phenylsulfonyl) -4- (1-piperazinyl) -1H- indazole hydrochloride

A solution of 1-phenylsulfonyl-4- (4-benzylpiperazin- 1-yl) -IH-indazole (433 mg, 1.0 mmol) in 1,2- dichloroethane is treated with 1-chloroethyl chloroformate (0.27 mL, 2.5 mmol) heated at reflux temperature for 2 hr, and concentrated in vacuo. The resultant residue is heated at reflux temperature in methanol for 1.5 hr, cooled, concentrated in vacuo and reconcentrated from ether. The resulting tan solid is triturated with ether and crystallized from hot ethanol to give the title compound as a tan solid 237 mg (63% yield), mp 203-205 °C, identified by HNMR and mass spectral analyses . EXAMPLE 59

Preparation of 4- [4- (2 -phenylethyl) piperazin- 1-yl] -1- (phenylsulfonyl) -lH-indazole hydrochloride

A mixture of l-phenylsulfonyl-4-piperazin-l-yl-lH- indazole (190 mg, 0.50 mmol) and K₂C0₃ (138 mg, 1.0 mmol) in dry acetonitrile is treated with phenethylbromide

(0.55 mL, 2.0 mmol), heated at reflux temperature under nitrogen for 8.5 h, treated with water and extracted with methylene chloride. The combined extracts are dried over MgS0₄ and chromatographed on an SCX column (Varian SCX Mega Bond Elut, 5 g) eluting with ethyl acetate to remove non-basic organic material and then with 1:99 triethylamine : ethyl acetate to afford, after concentration, the free amine of the title compound as a slightly yellow oil (198 mg, 89%) . The oil is dissolved in ether with a small amount of ethanol to aid solubility and treated with 1.0M HCl in ether. The solution is concentrated in vacuo and the resulting tan solid is treated with ether and suction filtered to afford the title compound as a light tan solid 209 mg, (87% yield) , mp 230-232 °C (dec) , identified by NMR and mass spectral analyses .

EXAMPLES 60-72

Preparation of 4-Heteroaryl-1-arylsulfonylindazole compounds

Using essentially the same procedures described in Examples 56-59 and employing the appropriate indazole substrate and suitable aryl, alkyl or acyl halide or arylsulfonyl chloride, the following compounds shown in Table IV are obtained and identified by NMR and mass spectral analyses.

TABLE IV

Ex. mp

No. Ri R₈ °C M+H

60 2 (p-fluorophenoxy) ethyl- phenyl 184-186 481

61 p-fluorophenyl-CO- (CH₂)₃- phenyl -- 507

62 phenyl-CO- -CH₂- phenyl 202-205 461

63 3 -phenylpropyl- phenyl 188-190 461

64 n-propyl- phenyl 258-260 385

65 benzyl phenyl-CH=CH- 233-235 459

66 benzyl p-fluorophenyl 240-241 451

67 benzyl p-chlorophenyl 238-239 467

68 benzyl naphthyl 147-149 483

69 benzyl p-methoxyphenyl 206-209 463 0 benzyl p- (trifluoro- 229-231 517 methoxy) phenyl

71 benzyl 2-(4,5- 235-237 507 dichloro- thienyl) -

72 benzyl p-tolyl 215-217 447 EXAMPLE 73

Preparation of 1- (4 -Aminophenylsulfonyl) -5-piperazin-l- yl-lH-indole hydrochloride

A solution of 5-aminoindole (6.23 g, 47 mmol), bis (2-chloroethyl) amine hydrochloride (16.8 g, 96 mmol) and triethylamine (19 mL, 141 mmol) in butanol is heated at 100 °C for 8 hours, cooled to room temperature and concentrated in vacuo to give 9.46 g of 5-piperazin-1-yl- IH-indole.

A solution of said indole in acetone and water is treated with di- tert-butyl dicarbonate (11.3 g, 47 mmol) and potassium carbonate (13 g, 96 mmol) . The mixture is stirred at room temperature overnight, the acetone evaporated and the remaining aqueous phase extracted with ethyl acetate. The extracts are dried over MgS0 and concentrated in vacuo to give a residue. The residue is purified by flash chromatography to give 4- (lH-indol-5- yl) -piperazine-1-carboxylic acid tert-butyl ester. A solution of said ester (60 mg, 0.2 mmol) in tetrahydrofuran is treated with sodium hydride (30 mg, 0.5 mmol) followed by N-acetylsulfanilyl chloride (25 uL, 0.2 mmol), shaken at room temperature for 16 hours and concentrated in vacuo to give 4- [1- (4- acetylaminophenylsulfonyl) -lH-indol-5-yl] -piperazine-1- carboxylic acid tert-butyl ester.

The thus-obtained ester is dissolved in methanol, treated with concentrated hydrochloric acid (100 uL) , shaken at 60 °C for 2 hours and concentrated in vacuo to give a residue. The residue is purified by HPLC to give the title product, 15 mg, identified by HPLC and mass spectral analyses (r.t. 2.37 min., M+H 357).

EXAMPLES 74-102

Preparation of Piperazinyl-1-arylsulfonylbenzimidazole and indole compounds

G= protecting group

Using essentially the same procedures described in Example 73 and employing the appropriate aminoindole or aminobenzimidazole substrate and suitable arylsulfonylchloride reagents, the following compounds shown in Table V are obtained and identified by HPLC and mass spectral analyses . TABLE V

Piperazinyl LCMS¹

Ex. Ring

No. Position X Rs Min. M+H

74 5 N phenyl 1.98 343

75 6 N phenyl 1.96 343

76 5 CH benzo-2 , 1 , 3 -thiadiazol- -4-yl 2.56 400

77 6 N benzo-2, 1, 3-thiadiazol- -4-yl 2.01 401

78 6 N 2 -bromophenyl 2.21 423

79 5 N p-bromophenyl 2.39 423

80 6 N p-bromophenyl 2.34 423

81 5 N 5-bromothien-2-yl 2.33 429

82 6 N 5-bromothien-2-yl 2.25 429

83 5 CH p- (n-butoxy) phenyl 3.23 414

84 5 N p- (n-butoxy) phenyl 2.79 415

85 6 N p- (n-butoxy) phenyl 2.73 415

86 5 CH 5-chloro-l, 3 -dimethyl - 2.49 395 pyrazol-4-yl 87 5 N 5-chloro-l, 3-dimethyl- 1.88 396 pyrazol-4-yl TABLE V ( cont ' d)

Piperazinyl LCMS^X Ex. Ring No. Position X Min. M+H

88 N 5-chloro-3-methylbenzo- 2 .88 448

[b] thien-2-yl

89 N 5-chloro-3-methylbenzo- 3, .10 448 [b] thien-2-yl

90 5 N 2 , 3-dichlorothien-5-yl 2 .59 418

91 6 N 2,3, -dichlorothien-5-yl 2 .77 418

92 5 N p-fluorophenyl 2 .08 361

93 6 N p-fluorophenyl 2, .40 361

94 5 N p-methoxyphenyl 2, .11 373

95 5 CCEH 2-naphthyl 2 .92 392

96 6 N 2-naphthyl 2 .43 393

97 5 CCEH p- (trifluoromethoxy) phenyl 2 .97 426

98 5 N p- (trifluoromethoxy) phenyl 2 .57 427

99 6 N p- (trifluoromethoxy) phenyl 2 .54 427

100 5 CCEH p-iodophenyl 2 .92 468

101 5 N - iodopheny1 2 .48 469

102 6 N -iodopheny1 2 .67 469 EXAMPLE 103

Comparative Evaluation of 5-HT6 Binding Affinity of Test Compounds

The affinity of test compounds for the serotonin 5- HT6 receptor is evaluated in the following manner. Cultured Hela cells expressing human cloned 5-HT6 receptors are harvested and centrifuged at low speed (1,000 x g) for 10.0 min to remove the culture media. The harvested cells are suspended in half volume of fresh physiological phosphate buffered saline solution and recentrifuged at the same speed. This operation is repeated. The collected cells are then homogenized in ten volumes of 50 mM Tris.HCl (pH 7.4) and 0.5 mM EDTA. The homogenate is centrifugedi at 40,000 x g for 30.0 min and the precipitate is collected. The obtained pellet is resuspended in 10 volumes of Tris.HCl buffer and recentrifuged at the same speed. The final pellet is suspended in a small volume of Tris.HCl buffer and the tissue protein content is determined in aliquots of 10-25 μl volumes. Bovine Serum Albumin is used as the standard in the protein determination according to the method described in Lowry et al . , J. Biol . Chem. , 193:265 (1951) . The volume of the suspended cell membranes is adjusted to give a tissue protein concentration of 1.0 mg/ml of suspension. The prepared membrane suspension

(10 times concentrated) is aliquoted in 1.0 ml volumes and stored at -70° C until used in subsequent binding experiments.

Binding experiments are performed in a 96 well microtiter plate format, in a total volume of 200 μl . To each well is added the following mixture: 80.0 μl of incubation buffer made in 50 mM Tris.HCl buffer (pH 7.4) containing 10.0 mM MgCl₂ and 0.5 mM EDTA and 20 μl of [³H] -LSD (S.A., 86.0 Ci/mmol, available from Amersham Life Science), 3.0 nM. The dissociation constant, K_D of the [³H] LSD at the human serotonin 5-HT6 receptor is 2.9 nM, as determined by saturation binding with increasing concentrations of [³H]LSD. The reaction is initiated by the final addition of 100.0 μl of tissue suspension. Nonspecific binding is measured in the presence of 10.0 μM methiothepin. The test compounds are added in 20.0 μl volume .

The reaction is allowed to proceed in the dark for 120 min at room temperature, at which time, the bound ligand-receptor complex is filtered off on a 96 well unifilter with a Packard Filtermate 196 Harvester. The bound complex caught on the filter disk is allowed to air dry and the radioactivity is measured in a Packard TopCount^® equipped with six photomultiplier detectors, after the addition of 40.0μl Microscint^®-20 scintillant to each shallow well. The unifilter plate is heat-sealed and counted in a PackardTopCount^® with a tritium efficiency of 31.0%.

Specific binding to the 5-HT6 receptor is defined as the total radioactivity bound less the amount bound in the presence of lO.OμM unlabeled methiothepin. Binding in the presence of varying concentrations of test compound is expressed as a percentage of specific binding in the absence of test compound. The results are plotted as log % bound versus log concentration of test compound. Nonlinear regression analysis of data points with a computer assisted program Prism^® yielded both the IC₅₀ and the Ki values of test compounds with 95% confidence limits. A linear regression line of data points is plotted, from which the IC₅₀ value is determined and the Ki value is determined based upon the following equation:

where L is the concentration of the radioactive ligand used and K_D is the dissociation constant of the ligand for the receptor, both expressed in nM.

Using this assay, the following Ki values are determined and compared to those values obtained by representative compounds known to demonstrate binding to the 5-HT6 receptor. The data are shown in Table VI, below.

TABLE VI

Test Compound 5- ■HT6 binding Ki

(Ex. No.) (nM)

1 1.0

2 2.0

3 1.0

4 15.0

5 1.0

14 24.0

18 6.0

27 56.0

TABLE VI (co t 'd)

Test Compound 5- •HTβ binding Ki

(Ex. No.) (nM)

30 220.0

33 45.0 35 15.0

36 3.0

37 59.0

38 5.0

40 4.0

41 7.0

42 4.0

43 7.0

44 1.0

46 5.0

47 6.0

48 14.0

49 10.0

50 17.0

51 7.0

52 25.0

53 4.0

57 14

58 0.3

59 1.0

60 306

61 3.0

62 12

63 6.0

TABLE VI (cont 'd)

Test Compound 5- HT6 binding Ki

(Ex. No. .) (nM)

64 2.0

65 172

66 84

67 87 68 14

69 116

70 251

71 81

72 56

73 34

79 19

81 44

83 38

86 44

89 24

90 30

91 6

96 37

101 18

Comparative Examples 5-HT6 binding Ki

Clozapine 6.0

Loxapine 41.4

Bromocriptine 23.0

Methiothepin 8.3

Mianserin 44.2

Olanzepine 19.5

As can be seen from the results set forth above, the compounds of the present invention have a high degree of affinity for the serotonin 5-HT6 receptor sub-type. Although two of the comparison compounds (clozapine and methiothepin) have similar 5-HT6 receptor affinity, they do not have the selectivity of the compounds of the present invention. The examples disclosed above demonstrate up to 50-fold selectivity for the 5-HT6 receptor when compared to their affinity at the 5-HT7 receptor.

Claims

WHAT IS CLAIMED IS :

A compound of formula I

( I )

wherein

Y is CR₇ or N with the proviso that when X is N, then

Y must be CR₇ ; Ri is H , Cι-C₆alkylcarbonyl , Cι-C₆alkoxycarbonyl or an

Cι-C₆alkyl , C₂-C₆alkenyl , C₂ -C₆alkynyl or cycloheteroalkyl group each optionally substituted; R₂, R₃, R , R₅ and R₆ are each independently H, halogen, OH or an optionally substituted Ci-

C_salkyl group; R₇ and R_Xi are each independently H, halogen or an Ci-

C₆alkyl, aryl, heteroaryl or Cι-C₆alkoxy group each optionally substituted; R₈ is an Cι-C₆alkyl, aryl or heteroaryl group each optionally substituted; R₉ is H, halogen or an Cι-C₆alkyl, Cι-C₆alkoxy, C₂- C₆alkenyl, aryl or heteroaryl group each optionally substituted; Rio is H, OH or an optionally substituted Cι-C₆alkoxy group ; m is an integer of 1, 2 or 3,^■ n is 0 or an integer of 1, 2 or 3 ; and represents a single bond or a double bond; or a pharmaceutically acceptable salt thereof.

2. The compound according to claim 1 wherein A is N and m is 2.

3. The compound according to claim 1 or claim 2 wherein R₈ is an optionally substituted phenyl group.

4. The compound according to any one of claims 1 to 3 wherein R₂, R₃, R , R5 and R_δ are H.

5. The compound according to any one of claims 1 to 4 wherein R_x is H or a Cι-C₆alkyl or cycloheteroalkyl group each optionally substituted.

6. The compound according to claim 1 selected from the group consisting of:

1- (phenylsulfonyl) -4 -piperazin- 1-yl-IH-indole ;

1- [ (2-bromophenyl) sulfonyl] -4-piperazin-l-yl-lH-indole;

1- [ (6-chloroimidazo [2, 1-b] [1,3] thiazol-5-yl) sulfonyl] -4- piperazin-1-yl-IH-indole; 1- [ (3 , 4 -dimethoxyphenyl) sulfonyl] -4-piperazin-l-yl-lH- indole; 1- [ (5-chloro-3-methyl-l-benzothien-2-yl) sulfonyl] -4- piperazin-1-yl-IH-indole; 1- [ (4-bromophenyl) sulfonyl] -4-piperazin-l-yl-lH-indole; 1- [ (5-bromothien-2-yl) sulfonyl] -4-piperazin-l-yl-lH- indole; 1- [ (4 , 5-dichlorothien-2-yl) sulfonyl] -4-piperazin-l-yl-lH- indole; methyl 4- [ (4-piperazin-l-yl-lH-indol-l-yl) sulfonyl] phenyl ether; 4-piperazin-l-yl-l- { [4-

(trifluoromethoxy) phenyl] sulfonyl} -lH-indole; 4- (4-benzylpiperazin-l-yl) -1- (phenylsulfonyl) -lH-indole; 4- (4-benzylpiperazin-l-yl) -1- [ (2-bromophenyl) sulfonyl] -

IH-indole; 4- (4-benzylpiperazin-l-yl) -1- [ (6-chloroimidazo [2,1- b] [1,3] thiazol-5-yl) sulfonyl] -IH-indole; 4- (4-benzylpiperazin-l-yl) -1- [(3,4- dimethoxyphenyl) sulfonyl] -IH-indole; 4- [4- (3-methoxybenzyl)piperazin-l-yl] -1- (phenylsulfonyl) -

IH-indole; 1- (phenylsulfonyl) -4- [4- (pyridin-4-ylmethyl) piperazin-1- yl] -IH-indole; 1- (phenylsulfonyl) -4- [4- (pyridin-3-ylmethyl) piperazin-1- yl] -IH-indole; 1- [ (2-bromophenyl) sulfonyl] -4- [4- (3- methoxybenzyl) piperazin-1-yl] -IH-indole; 1- [ (2-bromophenyl) sulfonyl] -4- [4- (pyridin-4- ylmethyl) piperazin-1-yl] -IH-indole; 1- [ (2-bromophenyl) sulfonyl] -4- [4- (pyridin-3- ylmethyl) piperazin-1-yl] -IH-indole; 1- (phenylsulfonyl) -5-piperazin-l-yl-lH-indazole; 1- (phenylsulfonyl) -6-piperazin-l-yl-lH-indazole; 1- [ (2-bromophenyl) sulfonyl] -6-piperazin-l-yl-lH-indazole 1- [ (4-bromophenyl) sulfonyl] -5-piperazin-l-yl-lH-indazole 1- [ (4-bromophenyl) sulfonyl] -6-piperazin-l-yl-lH-indazole 1- [ (5-bromothien-2-yl) sulfonyl] -5-piperazin-l-yl-lH- indazole; 1- [ (5-bromothien-2-yl) sulfonyl] -6-piperazin-l-yl-lH- indazole; 1- [ (4 -fluorophenyl) sulfonyl] -5-piperazin-l-yl-lH- indazole; 1- [ (4-fluorophenyl) sulfonyl] -6-piperazin-l-yl-lH- indazole; methyl 4- [ (5-piperazin-l-yl-lH-indazol-l- yl) sulfonyl] phenyl ethe ; 1-phenylsulfonyl-4- (4-propylpiperazin-l-yl) -IH-indazole; 1-phenylsulfonyl-4-piperazin-1-yl-lH-indazole; 1-phenylsulfonyl-4- (4-phenethylpiperazin-l-yl) -1H- indazole; l-phenylsulfonyl-4- [4- (3 -phenylpropyl) -piperazin-1-yl] -

IH-indazole; and the pharmaceutically acceptable salts thereof.

7. A method for the treatment of a disorder of the central nervous system related to or affected by the 5- HT6 receptor in a patient in need thereof which comprises administering to said patient a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt thereof as claimed in any one of claims 1 to 6.

8. The method according to claim 7 wherein said disorder is a motor disorder, anxiety disorder or cognitive disorder.

9. The method according to claim 7 wherein said disorder is schizophrenia or depression.

10. The method according to claim 8 wherein said cognitive disorder is a neurodegenerative disorder.

11. The method according to claim 10 wherein said neurodegenerative disorder is Alzheimer's disease or Parkinson's disease.

12. A pharmaceutical composition which comprises a pharmaceutically acceptable carrier and a compound of formula I or a pharmaceutically acceptable salt thereof as claimed in any one of claims 1 to 6.

13. A method for the preparation of a compound of formula I .

( I ) wherein

X is CRii or N;

Y is CR₇ or N with the proviso that when X is N, then

Y must be CR₇ ; Ri is (Cι-C₆alkyl ) carbonyl , (Cι-C₆alkoxy) carbonyl or an Cι-C₆alkyl , C₂-C₆alkenyl , C₂-C₆alkynyl or cycloheteroalkyl group each optionally substituted; R₂, R₃, R , R₅ and R₆ are each independently H, halogen, OH or an optionally substituted Ci-

C₆alkyl group; R₇ and Rn are each independently H, halogen or an C -

C₆alkyl, aryl, heteroaryl or alkoxy group each optionally substituted; R₈ is an Cι-C₆alkyl, aryl or heteroaryl group each optionally substituted; R₉ is H, halogen or an Cι-C₆alkyl, Cι-C₆alkoxy, C₂-

C₆alkenyl, aryl or heteroaryl group each optionally substituted; Rio is H, OH or an optionally substituted Cι-C₆alkoxy group; m is an integer of 1, 2 or 3 ; n is 0 or an integer of 1, 2 or 3; and represents a single bond or a double bond said method which comprises one of the following:

i) reacting a compound of formula:

wherein the dotted line, n, m, R₂, R₃, R , R5, R_ , s>/ X Y and A are as defined above and G is a protecting group, with a suphonylating agent containing the group: j

R₈SO₂

wherein R₈ is as defined above, and if required removing the protecting group G to give a compound of Formula I wherein Ri is hydrogen;

or

ii) reacting a compound of formula

wherein the dotted line, n, m, R_{l t} R₂, R₃, R₄, R₅, Re , R₉, X, Y and A are as defined above, with a sulphonylating agent containing the group

R₈SO₂

wherein R₈ is as defined above, to give a compound of formula (I) ;

or

iii) reacting a compound of formula I wherein R_x is hydrogen with a compound of formula :

Ri — L wherein R_x is as defined above (excepting hydrogen) and L is a suitable leaving group, e.g. halogen or SMe to give a corresponding compound of formula I ; or

iv) alkylating a compound of formula (I) wherein A is CRio in. which Rι₀ is OH with an alkylating agent containing the group R_a where R_a is optionally substituted alkyl to give a compound of formula (I) wherein Rι₀ is optionally substituted alkoxy;

or