Patent ID: 6858640

Claim:
A compound, prodrug, pharmaceutically acceptable salt or solvate thereof of the formula: wherein R 1 is hydrogen; R 2 is hydrogen or lower alkyl; R 3 is hydrogen; R 4 is —COOR 13 wherein R 13 is hydrogen or ester moiety; R 5 is hydrogen, or R 3 and R 5 taken together may form a bond; R 6 is hydrogen; R 7 is hydrogen, halogen, optionally substituted lower alkyl, cycloalkyl, or cycloalkyl(lower)alkyl; R 8 is hydrogen, optionally substituted lower alkyl, cycloalkyl, or cycloalkyl(lower)alkyl; and R 9 , R 10 and R 11 are each independently hydrogen, halogen, optionally substituted lower alkyl, cycloalkyl, or cycloalkyl(lower)alkyl.