Patent ID: 6852710

Claim:
A compound represented by the following structural formula: wherein: R 1 is (C 1-6 ) alkyl, and optionally substituted by halogen; R 2 is H, or SO 2 NHR, with R being hydrogen or (C 1-6 )alkyl; R 3 is selected from the group consisting of hydrogen and (C 1-6 ) alkyl, and optionally substituted by halogen; R 4 is hydrogen, (C 1-6 ) alkyl, (C 2-6 ) alkenyl, (C 2-6 ) alkynyl, aryl, or heteroary; R 5 is (C 1-2 )alkyl; R 6 is O, NOR, (H, OR), or (H, OSO 2 NHR), wherein R is hydrogen, (C 1-6 ) alkyl or (C 1-6 ) acyl; and R 7 is hydrogen or (C 1-6 ) alkyl.