A process for preparing the polyurethane derivative, the process including: providing
a polyurethane having a urethane amino moiety, providing a multifunctional linker
reagent of a formula: LG-RL-(FG)n, wherein n is an integer
from 1 to 3, FG is a functional group, which is a halogen, a carboxyl group, a
sulfonate ester, or an epoxy group, LG is a leaving group, which is a halogen,
a carboxyl group, a sulfonate ester, or an epoxy group, and RL is an
(n+1)-valent organic radical having at least one carbon atom; providing a protected
thiol-containing reagent of a formula RC(O)SH, or a salt thereof, wherein
R is a C1 to C6 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: RL-(FG)n;
reacting the polyurethane with a protected thiol-containing reagent to form the
polyurethane derivative.
