Patent ID: 7244764

Claim:
A compound of Formula I: wherein: R 1 is an unsubstituted indolyl or substituted or unsubstituted tetrahydronaphthyl; R 2 is selected from a group consisting of hydrogen, alkyl, mercaptoalkyl, alkenyl, alkynyl, cycloalkyl, aryl, arylalkyl, thiazolyl, triazolyl, imidazolyl, benzothiazolyl, and benzoimidazolyl; Y is SO 3 − X + or SSO 3 − X + ; X + is hydrogen, a cationic group, or an ester forming moiety; and L 1 is independently an unsubstituted C 1 -C 5 alkyl group or absent; L 2 is a unsubstituted C 3 alkyl group, or a pharmaceutically acceptable salt, ester or prodrug thereof.