Synthesis and structural studies of 2,3-disubstituted poly(beta-peptide)s

The synthesis of 2,3-disubstituted poly(beta -peptide)s (nylon-3 analogues) bearing the benzyloxy group at position 3 and the diethoxymethyl or the is obutoxycarbonyl group at position 2, is described. Both optically pure and racemic forms were prepared for each case and all them were characterized b y standard methods. The structure of these poly(beta -peptide)s was prelimi nary examined by X-ray diffraction and infrared spectroscopy. It was conclu ded that they do not tend to adopt the alpha -helixlike conformation charac teristic of poly(beta -L-aspartate)s but rather a contracted conformation w ith amide groups in the nonassociated state.