Patent ID: 7678795

Claim:
A compound of the formula: wherein R 1 and R 2 together with the carbon atoms C a and C b to which they are attached form R 3 is hydrogen, alkyl, cycloalkyl or trifluoromethyl; R 4 is benzyl, cycloalkyl, arylcycloalkyl, adamantyl, aryl or heterocyclyl, wherein benzyl, cycloalkyl, arylcycloalkyl, aryl and heterocyclyl are optionally substituted with one to three substituents independently selected from alkyl, cycloalkyl, alkoxy, hydroxy, halogen, trifluormethyl, trifluoromethoxy, benzyl, phenyl and phenyl substituted with one to three substituents independently selected from alkyl, alkoxy, hydroxy, cycloalkyl, halogen and trifluoromethyl; or pharmaceutically acceptable salts and esters thereof.