Heterobifunctional poly(?-caprolactone): Synthesis of ?-cholesterol-?-pyrene PCL via combination of ring-opening polymerization and click chemistry

Abstract

A well-defined novel alpha-cholesterol and omega-pyrene heterobifunctional poly(epsilon-caprolactone) (Chol-PCL-Pyr) was synthesized by a combination of ring-opening polymerization (ROP) and click chemistry techniques. A cholesterol compound with hydroxyl functional group was used as the initiator in the ROP of epsilon-caprolactone (epsilon-CL) to prepare alpha-cholesterol-omega-hydroxy PCL polymer (Chol-PCL-OH). omega-Hydroxy functionality of Chol-PCL-OH was then successfully converted into bromide and azide. Further end-group modification of omega-azide poly(epsilon-caprolactone) (Chol-PCL-N-3) was achieved quantitatively by copper (1)-catalyzed cycloaddition of azide functional group and 1-ethynyl pyrene, which led to the desired PCL with alpha-cholesterol and omega-pyrene groups (Chol-PCL-Pyr). The effect of molar ratio of epsilon-CL to the initiator on the molecular weight of the obtained CholPCL-Pyr was also investigated. (C) 2015 Elsevier B.V. All rights reserved.