Histone deacetylase inhibitors

A compound of formula (I):

• or the tautomeric form, stereoisomer, pharmaceutically acceptable salt or composition or prodrug thereof;
• wherein R1 and R2 represent substituted or unsubstituted groups selected from aryl, cycloalkyl, cycloalkenyl, arylalkenyl, heteroarylalkenyl, arylalkynyl, heterocyclyl and heteroaryl;
• R represents H, or substituted or unsubstituted groups selected from linear or branched alkyl, aryl, heteroaryl and heterocyclyl;
• X represents a group selected from —CONR4—, —NR4SO2—, —SO2NR4—, —SO2O—, —O—SO2—, —CONR4CONR4—, —NR4CO—, —OCONR4—, —NR4CONR4—, —NR4— and —O—;
• R4 represents H, or substituted or unsubstituted groups selected from alkyl, aryl, heterocyclyl, heteroaryl, cycloalkyl and cycloalkenyl;
• Ar represents substituted or unsubstituted groups selected from aryl and heteroaryl;
• R3 represents a group selected from ortho substituted aniline, phenol, amino aryl, hydroxy aryl, amino heteroaryl and —OR5;
• R5 represents a group selected from H, -COR6, substituted or unsubstituted groups selected from alkyl, aryl and heterocyclyl;
• R6 represents substituted or unsubstituted groups selected from alkyl, aryl and heterocyclyl;
• wherein n=0 or 1, o=0-1, p=1, q=0-3;
• with the proviso that if X=—OCONH—, then n and p=1;
• and
• when the groups R, R1, R2, R4 and Ar have one or more substituents , the substituents are selected from halogens;
• hydroxy;
• nitro;
• cyano;
• azido;
• nitroso;
• amino;
• hydrazine;
• formyl;
• alkyl;
• alkenyl;
• alkynyl;
• haloalkyl group;
• haloalkoxy;
• aralkoxy;
• cycloalkyl;
• aryl;
• alkoxy;
• aryloxy;
• acyl;
• acyloxy;
• acyloxyacyl;
• heterocyclyl;
• heteroaryl;
• alkylamino;
• acylamino;
• alkoxycarbonyl;
• aryloxycarbonyl;
• alkylsulfonyl;
• arylsulfonyl;
• alkylsulfinyl;
• arylsulfinyl;
• alkylthio;
• arylthio;
• sulfamoyl;
• alkoxyalkyl and carboxylic acids and its derivatives;
• the substituents which in turn are optionally further substituted with hydroxy;
• halogens;
• nitro;
• cyano;
• azido;
• nitroso;
• amino;
• hydrazine;
• alkyl;
• alkoxy;
• aryl;
• cycloalkyl and heteroaryl.