Patent ID: 8748388

Claim:
A compound of formula I wherein R 1 , R 4 , R 6 , and R 9 are each independently selected from hydrogen, substituted or unsubstituted C 1 -C 12 alkyl, substituted or unsubstituted C 2 -C 12 alkenyl and substituted or unsubstituted C 2 -C 12 alkynyl; R 3 and R 8 are each independently a substituted or unsubstituted C 1 -C 12 mercaptoalkyl group wherein the mercapto group may be optionally protected; or R 3 with R 8 form a group —CH 2 —S—S—CH 2 —; R 2 is hydrogen; R 7 is hydrogen; or the pair R 1 -R 2 and/or R 6 -R 7 independently form a substituted or unsubstituted C 1 -C 12 alkylidene or together with the corresponding C atom to which they are attached form a substituted or unsubstituted C 3 -C 12 cycloalkyl; R 5 and R 10 are each independently selected from amino protecting group and —(C═O)R″ wherein each R″ is independently selected from substituted or unsubstituted heterocyclic group and substituted or unsubstituted heterocyclyalkyl group; R a , R b , R c , R d , R e , and R f are each independently selected from hydrogen and substituted or unsubstituted C 1 -C 12 alkyl; Y is selected from S, O, and NR i ; R b is selected from substituted or unsubstituted C 1 -C 12 alkyl, a —(CH 2 —CH 2 O) n —CH 3 group wherein a is from 1 to 25, substituted or unsubstituted C 2 -C 12 alkenyl and substituted or unsubstituted C 2 -C 12 alkynyl; and R i is a group selected from hydrogen, substituted of unsubstituted C 1 -C 12 alkyl, a —(CH 2 —CH 2 O) n —CH 3 group wherein n is from 1 to 25, substituted or unsubstituted C 2 -C 12 alkenyl and substituted or unsubstituted C 2 -C 12 alkynyl; or a pharmaceutically acceptable salt, tautomer, ester or stereoisomer thereof.