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New polymer syntheses. IV. Polypeptides of lysine and ornithine with pending pyrimidine bases
Author(s) -
Kricheldorf Hans R.,
Fehrle Martin
Publication year - 1982
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360211103
Subject(s) - chemistry , hydrobromide , lysine , polymerization , solubility , pyrimidine , polymer , proton nmr , polymer chemistry , vapor pressure osmometry , stereochemistry , side chain , nmr spectra database , osmometer , amino acid , organic chemistry , spectral line , biochemistry , vapor pressure , physics , astronomy
Starting with β‐methoxy methacryloylisocyanate, β‐methoxy methacrylisothiocyanate, and β‐isocyanatopropionyl chloride, on the one hand, and N α ‐Z‐lysine or N α ‐Z‐ornithine, on the other hand, N α ‐Z‐amino acids with pyrimidine bases in the side chain were synthesized. These Z‐protected nucleoamino acids were converted to the corresponding N‐carboxyanhydrides (NCAs) via the silylester method. In the case of 2‐thiothymine derivatives, the reaction intermediate of the NCA synthesis caused benzylation of the thioxo‐ group, so that a new class of 2‐mercaptopyrimidine derivatives was isolated unexpectedly. The poly(nucleoamino acids) obtained by polymerization of the nucleoamino acid NCAs were characterized by elemental analyses, optical rotations 1 H‐nmr and 13 C‐nmr spectra. Vapor pressure osmometry revealed that the DP s were in the range of 20–30. Their spectra suggest a helical secondary structure. While all homopolypeptides are insoluble in water, copolypeptides containing L ‐lysine N ε ‐hydrobromide possess good solubility in water.