The invention provides a method for preparing a 1 benzotriazolylcarbonate ester of a water soluble and non peptidic polymer by reacting {HEAD ~ a terminal hydroxyl group} of {TAIL ~ a water} soluble and non peptidic polymer with dicarbonate in the presence of an amine base and an organic solvent 
The invention provides a method for preparing a 1 benzotriazolylcarbonate ester of a water soluble and non peptidic polymer by reacting { HEAD ~ a terminal hydroxyl group } of { TAIL ~ a water } soluble and non peptidic polymer with dicarbonate in the presence of an amine base and an organic solvent
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH