Sequence peptide polymers: Part 1. Poly(leucyl-leucyl-aspartic acid-β-benzyl ester)—synthesis and some conformational aspects in solutions☆

Abstract A polypeptide containing ordered sequence of leucyl and β-benzyl-aspartyl residues has been synthesized via the p -nitrophenyl active ester method. Polymerization of the TFA H-Leu-Leu-Asp (OBzl) ONp was carried out in dimethyl sulphoxide and in chloroform by mixing the salt with triethylamine. The polymer obtained showed a relatively high [η] and α-helical conformation in solution as well as in the solid state, as shown by optical rotatory dispersion and infra-red spectra, respectively.