Phenolic resins for solid‐phase peptide synthesis: Copolymerization of styrene and <i>p</i>‐acetoxystyrene

Abstract

Abstract Details are given of the synthesis and purification of p ‐acetoxystyrene and its solution and suspension copolymerization with styrene. Reactivity ratios, evaluated by the Tidwell‐Mortimer method, were r 1 ( p ‐acetoxystyrene) = 1.18, and r 2 (styrene) = 0.88 for (bulk) solution copolymerization. Corresponding values of the reactivity ratios for suspension copolymerization were, within experimental error, indistinguishable from unity. Thus the copolymer composition is governed simply by the monomer feed composition. Use of a specially designed reactor vessel permits convenient suspension copolymerization of styrene, p ‐acetoxystyrene, and divinylbenzene to give crosslinked resins having comparatively narrow particle size distributions. Acetoxy groups in the crosslinked resin are cleaved by hydrazine hydrate under very mild conditions to give crosslinked polystyrenes having phenolic groups which, in turn, provide a useful alternative to the more usual chloromethylated polystyrene resins for solid‐phase peptide synthesis.