Synthesis of Polymers of Isocyanides Derived from Tripeptides Containing Imidazolyl, Carboxyl, and Hydroxymethyl Groups

Article abstract of DOI:10.1021/jo00217a023

Three optically active polymers of isocyanides, n, which contain imidazolyl, carboxyl, and hydroxymethyl functions in their side chains R, are described.The polymers are derived from the following diastereomeric tripeptides: L-Ala-L-His-L-Ser, L-Ala-L-His-D-Ser, and D-Ala-L-His-L-Ser.The terminal amino groups of these tripeptides are converted into isocyano functions, which are subsequently polymerized with catalytic amounts of nickel(II) chloride.The molecular weights of the polymers are in the M_v range 20000-35000.The CD spectra reveal that the polymers derived from L-Ala-L-His-L-Ser and L-Ala-L-His-D-Ser have right-handed helical configuractions.The pK_a values of the imidazolyl and carboxyl groups in the polymers have increased as compared to model compounds.This suggests that strong electrostatic interactions exist between these groups.