Method for producing active carbonic acid ester of polyethylene glycol, and active carbonic acid ester of polyethylene glycol

Abstract

Activated polyethylene glycol with high purity can be obtained by a method including: a step (a) of reacting polyethylene glycol having a hydroxyl group with one or more active carbonic acid reagents selected from the group consisting of disuccinimidyl carbonate and p-nitrophenylchloroformate in presence of a base in an aprotic solvent which is immiscible with water, to obtain a composition containing an active carbonic acid ester of polyethylene glycol and the active carbonic acid reagent being unreacted, a step (b) of partially removing the active carbonic acid reagent by filtering the composition obtained in the step (a), and then obtaining a composition by adding an alcohol containing an acidic functional group to react with the unreacted active carbonic acid reagent, and a step (c) of removing a reaction product of the alcohol containing an acidic functional group and the active carbonic acid reagent, the alcohol containing an acidic functional group, and a decomposition product of the active carbonic acid reagent by washing the composition obtained in the step (b) with water.

Dependencies are inferred from the claim text.