Patent ID: 6900282

Claim:
A process for preparing the polyurethane derivative, the process comprising: providing a polyurethane comprising a urethane amino moiety; providing a multifunctional linker reagent of a formula: LG-R L -(FG) n wherein n is an integer from 1 to 3, FG is a functional group selected from the group consisting of a halogen, a carboxyl group, a sulfonate ester, and an epoxy group, LG is a leaving group selected from the group consisting of a halogen, a carboxyl group, a sulfonate ester, and an epoxy group, and R L is an (n+1)-valent organic radical comprising at least one carbon atom; providing a protected thiol-containing reagent of a formula R—C(O)SH, or a salt thereof, wherein R is a C 1 to C 6 alkyl group; reacting the multifunctional linker reagent with the urethane amino moiety to form a polyurethane substituted with at least one substituent group of a formula —R L -(FG) n ; reacting the polyurethane substituted with at least one substituent group with a protected thiol-containing reagent to form the polyurethane comprising the thiol substituent pendant from a urethane nitrogen.