Patent ID: 8030304

Claim:
A compound of Formula I wherein: R 1 and R 2 are independently ethyl or n-propyl; R 3 is hydrogen, Cl, Br, methyl, trifluoromethyl or methoxy; R 4 is hydrogen, Br, R a R b N—, methoxymethyl, n-butyl, acetamido, pyridin-4-yl, morpholin-4-yl, R a and R b are independently hydrogen, C 1 -C 3 alkyl, H 2 NCH 2 CH 2 —, (CH 3 ) 3 COC(O)NHCH 2 CH 2 —, or CH 3 CH 2 CH 2 NHCH 2 CH 2 —; or a pharmaceutically acceptable salt thereof.