Patent ID: 8183281

Claim:
A compound of formula wherein R 1 is hydrogen or (C 1-8 )alkyl, and R 2 is a non-aromatic 5-membered unsubstituted or one- or morefold substituted heterocyclic ring system having 1 to 4 heteroatoms selected from O, S; or R 1 and R 2 together with the —CH group to which they are attached form a non-aromatic 5-membered unsubstituted or one- or morefold substituted heterocyclic ring system having 1 to 4 heteroatoms selected from O, S, R 3 is hydrogen, halogen, cyano, (C 1-8 )alkyl, (C 1-8 )alkoxy, amino, (C 1-8 )alkylamino, di(C 1-8 )alkylamino, (C 1-8 )alkylaminocarbonyl, di(C 1-8 )alkylaminocarbonyl, aminosulfonyl, (C 1-8 )alkylaminosulfonyl, di(C 1-8 )alkylaminosulfonyl, (C 1-8 )alkylsulfonyl, heterocyclylcarbonyl or heterocyclylsulfonyl, wherein heterocyclyl is a 5 or 6 membered unsubstituted or one- or morefold substituted ring system having 1 to 4 heteroatoms selected from N, O, S, R 4 is hydrogen, halogen or cyano; or a pharmaceutically acceptable salt thereof.