Synthesis of poly-L-asparagine and poly-L-glutamine

Poly-β-N-diphenylmethyl-L -asparagine and poly-γ-N-diphenylmethyl-L -glutamine were prepared from the corresponding N-carboxyanhydrides. Poly-L -aspuragine and poly-L -glutamine were obtained by removal of the diphenylmethyl protecting groups with liquid anhydrous hydrofluoric acid.