Patent ID: 7074778

Claim:
A compound having the formula: wherein X is selected from the group consisting of â€”CH 2 â€”PO(OR 5 ) 2 , â€”NHâ€”SO 2 â€”R 5 , â€”NHâ€”COâ€”OR 5 , â€”CH 2 â€”COâ€”NH 2 , â€”CH 2 â€”COâ€”NHâ€”R 8 , â€”CH 2 â€”CO 2 â€”R 5 , R 1 is selected from the group consisting of R 6 â€”NHâ€”, R 2 , R 3 , and R 4 are each independently selected from the group consisting of H, â€”OAc, and R 5 is a C 1-12 alkyl; R 6 is selected from the group consisting of C 1-6 alkyl and phenyl; and R 7 and R 8 are each independently selected from the group consisting of H, C 1-6 alkyl and phenyl.