Synthesis of crosslinked poly(α‐amino acids) with various functional groups

Abstract

AbstractThe esterification of the carboxyl group in copoly(γ‐benzyl‐L‐glutamyl‐L‐glutamic acid) was carried out using N‐hydroxysuccinimide and dicyclohexylcarbodimide to yield the activated site for the coupling reaction with amino compounds. The α‐helix stability of the reactive copolymer thus obtained is remarkably affected in the presence of succinimide ring. This copolymer was proved to react nearly completely with amino alcohols such as 2‐aminoethanol, 3‐aminopropanol, and diethanolamine. The copoly(N5‐hydroxyalkyl‐L‐glutamine) thus prepared is insoluble in water, since the benzyl ester remains in this copolymer. The copoly(α‐amino acids) having another functional group were also prepared using aminoalkylsilane. Crosslinked poly(α‐amino acids) were prepared by the reaction of the reactive copolymer with a low‐molecular‐weight polymer of PBLG having one amino group on each end of its main chain which was obtained from the corresponding NCA using p‐diaminobenzene as an initiator. Another crosslinked polymer was prepared using an alkyl diamine such as 1,6‐diaminohexane or 1,12‐diaminododecane as a crosslinking reagent. The crosslinked copoly(α‐amino acids) bearing the activated site are able to further react with various compounds having amino groups.