Dipeptidyl peptidase IV inhibitors, process for their preparation and compositions containing them

A compound of general formula (I)

• wherein:
• Y is —S(O)m—, —CH2—, CHF, or —CF2;
• m is 0, 1, or 2;
• X is a bond, C1- C5 alkyl, or —C(═O)—;
• the dotted line [ - - - ] in the carbocyclic ring represents an optional double bond;
• R1 is substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroaryl ring, substituted or unsubstituted heterocyclic ring, substituted or unsubstituted heterocyclylalkyl, substituted or unsubstituted heteroarylalkyl, CN, —COOR3, —CONR3R4, —OR3, —NR3R4, or NR3COR4,
• with the proviso that the heteroaryl ring and the heterocyclic ring in R1 is not a five-membered ring having at least one nitrogen atom;
• R2 is hydrogen, nitrile (—CN), COOH, or an isostere of a carboxylic acid;
• R3 and R4 may be the same or different and are independently hydrogen, nitro, hydroxy, cyano, formyl, acetyl, halogen, substituted or unsubstituted amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroaryl ring, substituted or unsubstituted heterocyclic ring, substituted or unsubstituted heterocyclylalkyl, substituted or unsubstituted heteroarylalkyl, or a substituted or unsubstituted carboxylic acid derivative, or a tautomeric form, , stereoisomer, enantiomer, diastereomer, N-oxide, or pharmaceutically acceptable salt thereof.