Patent ID: 7250431

Claim:
A compound of formula I: wherein R 1 is selected from the group consisting of amino, aryl, heteroaryl, substituted aryl, and substituted heteroaryl, wherein heteroaryl is an aromatic 5- to 10-membered ring which has one or more hetero atoms selected from the group consisting of nitrogen, oxygen and sulfur as ring atoms, wherein substituted aryl is aryl substituted with from one to three substituents, independently selected from halogen, trifluoromethyl, trifluoromethoxy, amino, alkyl, alkoxy, alkylcarbonyl, cyano, carbamoyl, alkoxycarbamoyl, methylendioxy, carboxy, alkoxycarbonyl, aminocarbonyl, alkyaminocarbonyl, dialkylaminocarbonyl, hydroxy, nitro, alkyl-SO 2 —, amino-SO 2 —, and cycloalkyl, and wherein substituted heteroaryl is heteroaryl substituted on one or more ring carbon atoms with a group selected from the group consisting of cyano, trifluoromethyl, trifluoromethoxy, alkyl-SO 2 —, amino-SO 2 —, halogen, alkoxy, hydroxy, amino, cycloalkyl, alkylcarbonyl, aminocarbonyl nitro, alkyl, and alkoxycarbonyl; R 2 is hydrogen or alkyl; R 3 is hydrogen, alkyl or halogen; R 4 is alkyl or halogen; R 5 is hydrogen, alkyl or halogen; a is zero or 1; b is zero, 1 or 2; or a pharmaceutically acceptable salt or ester thereof.