Patent ID: 8258173

Claim:
A compound having the formula: wherein: R 1 is hydrogen, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 1 -C 6 alkoxy, or C 2 -C 6 alkenoxy; R 2 is C 1 -C 6 alkyl-NHCOCH 3 or C 2 -C 6 alkenyl-NHCOCH 3 ; R 3 is CO(C 1 -C 6 alkyl), CO(C 2 -C 6 alkenyl), C 1 -C 6 alkoxy, or C 2 -C 6 alkenoxy; and R 4 is C 1 -C 6 alkoxy or C 2 -C 6 alkenoxy.