Patent ID: 7407961

Claim:
A compound of formula (I): wherein R 1 is wherein R 6 is hydrogen, or optionally substituted lower alkyl; R 7 hydrogen or halogen; R 8 is lower alkyl; R 2 is hydrogen; hydroxy; halogen; cyano; acyl; or lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, aryloxy, arylthio, aryl, heterocyclic group or amino, each of which is optionally substituted by substituent(s); R 3 and R 4 are independently hydrogen, lower alkyl or acyl; and R 5 is cyano; or lower alkenyl, lower alkynyl, aryl or heterocyclic group, each of which is optionally substituted by substituent(s); or a salt thereof.