Patent ID: 7790711

Claim:
A compound of formula (I): wherein: R 1 is H or lower alkyl; R 2 is lower alkyl, —(CH 2 ) n -cycloalkyl, —(CH 2 ) n -heterocycloalkyl, —(CH 2 ) n -aryl, —(CH 2 ) n -heteroaryl, —(CH 2 ) n OH, —(CH 2 ) n CH(CH 3 )OH or —(CH 2 ) n OCH 3 ; or R 1 and R 2 , together with the N atom to which they are attached, form a 5- to 7-membered monocyclic ring, which contains the N atom to which R 1 and R 2 are attached, and optionally another hetero atom which is selected from O and S, unsubstituted or mono- or bi-substituted with hydroxy, lower alkyl or —(CH 2 ) n OH; R 3 is one or more substituents selected from H, halogen, lower alkyl and lower alkoxy; R 4 is H, OH, NHC(═O)CH 3 or NHS(═O)(═O)CH 3 ; n is 1, 2, 3 or 4; and pharmaceutically acceptable salt thereof.