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

1. A compound of formula I

wherein

A is N;

X is CR 11 or N;

Y is CR 7 or N with the proviso that when X is N, then Y must be CR 7 and with the further proviso that one of X and Y must be N;

R 1 is H, C 1 -C 6 alkylcarbonyl, C 1 -C 6 alkylcarbonyloxy or an C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynl or cycloheteroalkyl group each optionally substituted;

R 2 , R 3 , R 4 , R 5 and R 6 are each independently H, halogen, OH or an optionally substituted C 1 -C 6 alkyl group;

R 7 and R 11 are each independently H, halogen or an C 1 -C 6 alkyl, aryl, heteroaryl or C 1 -C 6 alkoxy group each optionally substituted;

R 8 is an C 1 -C 6 alkyl, aryl or heteroaryl group each optionally substituted;

R 9 is H, halogen or an C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 1 -C 6 alkenyl, aryl or heteroaryl group each optionally substituted;

m is an integer of 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 X is CR 11 and Y is N.

3. The compound according to claim 1 wherein R 8 is an optionally substituted phenyl group.

4. The compound according to claim 1 wherein R 2 , R 3 , R 4 , R 5 and R 6 are H.

5. The compound according to claim 2 wherein R 1 is H or a C 1 -C 6 alkyl or cycloheteroalkyl group each optionally substituted.

6. A method for the treatment of a disorder of the central nervous system related to or affected by the 5-HT6 receptor selected from schizophrenia and depression in a patient in need thereof which comprises administering to said patient a therapeutically effective amount of a compound of formula I as described in claim 1 .

7. A pharmaceutical composition which comprises a pharmaceutically acceptable carrier and an effective amount of a compound of formula I

wherein

A is N;

X is CR 11 or N;

Y is CR 7 or N with the proviso that when X is N, then Y must be CR 7 and with the further proviso that one of X and Y must be N;

R 1 is H, C 1 -C 6 alkylcarbonyl, C 1 -C 6 alkylcarbonyloxy or an C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynl or cycloheteroalkyl group each optionally substituted;

R 2 , R 3 , R 4 , R 5 and R 6 are each independently H, halogen, OH or an optionally substituted C 1 -C 6 alkyl group;

R 7 and R 11 are each independently H, halogen or an C 1 -C 6 alkyl, aryl, heteroaryl or C 1 -C 6 alkoxy group each optionally substituted;

R 8 is an C 1 -C 6 alkyl, aryl or heteroaryl group each optionally substituted;

R 9 is H, halogen or an C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 1 -C 6 alkenyl, aryl or heteroaryl group each optionally substituted;

m is an integerof 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.

8. The composition according to claim 7 wherein R 8 is an optionally substituted phenyl group.

9. The composition according to claim 7 wherein X is CR 11 and Y is N.

10. A method for the preparation of a compound of formula

wherein

A is N;

X is CR 11 , or N;

Y is CR 7 or N with the proviso that when X is N, then Y must be CR 7 and with the further proviso that one of X and Y must be N;

R 1 is H, C 1 -C 6 alkylcarbonyl, C 1 -C 6 alkylcarbonyloxy or an C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynl or cycloheteroalkyl group each optionally substituted;

R 2 , R 3 , R 4 , R 5 and R 6 are each independently H, halogen, OH or an optionally substituted C 1 -C 6 alkyl group;

R 7 and R 11 are each independently H, halogen or an C 1 -C 6 alkyl, aryl, heteroaryl or C 1 -C 6 alkoxy group each optionally substituted;

R 8 is an C 1 -C 6 alkyl, aryl or heteroaryl group each optionally substituted;

R 9 is H, halogen or an C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 1 -C 6 alkenyl, aryl or heteroaryl group each optionally substituted;

m is an integer of 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 reacting a compound of formula Ia

wherein A, X, R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , m and n are as defined hereinabove for formula I with a compound R 1 -Hal wherein R 1 is as defined hereinabove for formula I and Hal is CI, Br or I.