Patent ID: 7229996

Claim:
A compound having a structural formula I: a pharmaceutically acceptable salt thereof, wherein: R is hydrogen or acetyl, L is a linker selected from one or any combination of two or three of the following: (a) (C 1 -C 6 )alkylene, (b) (C 3 -C 8 )cycloalkylene, (c) arylene, (d) heteroarylene, (e) bivalent heterocyclic group containing 1 to 3 heteroatoms, (f) —(═O)—, (g) —C(═N—O—R 11 )—, wherein R 11 represents hydrogen, (C 1 -C 6 )alkyl, or substituted (C 1 -C 6 alkyl), (h) —C═N—, (i) —O—, (j) —S(O) n —, wherein n is number between 0 and 2, and (k) —N(R 12 )—, wherein R 12 represents hydrogen, (C 1 -C 6 )alkyl. or substituted (C 1 -C 6 alkyl), wherein the carbon or nitrogen atoms of the linker group are substituted by 0 to 3 substituents selected from (C 1 -C 6 )alkyl, substituted (C 1 -C 6 )alkyl, heterocycloalkyl, amino, (C 1 -C 6 )alkylamino, di(C 1 -C 6 )alkylamino. hydroxyl, or (C 1 -C 6 )alkoxy; and provided L is not wherein R 1 is H, C 1 -C 6 )alkyl, or substituted (C 1 -C 6 )alkyl.