Synthesis of a polyamide from l-aspartic acid and l-lysine

Summary

A non-peptidic polyamide having a regular structure was synthesized by the polycondensation of N^ɛ-(β-L-aspartyl)-L-lysine via the active ester method. Amino groups of L-lysine were orthogonally protected with benzyl and t-butoxy carbonyl groups, and the α-carboxylic group of L-aspartic acid was masked as benzyl ester, the carboxylic group of L-lysine being activated as pentachlorophenyl ester. Coupling was achieved by the mixed anhydride method. The polycondensation of the dimeric amino acid derivative was carried out in two steps, and provided a polymer with a reduced viscosity of 0,16 dl/g (c=1%, hexafluoroisopropanol).