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Copolymerization of sarcosine‐NCA and l‐leucine‐NCA or l‐phenylalanine‐NCA
Author(s) -
Kricheldorf Hans R.,
Tönnes KaiUwe
Publication year - 1991
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19910420126
Subject(s) - sarcosine , chemistry , reactivity (psychology) , copolymer , polymer chemistry , monomer , nuclear magnetic resonance spectroscopy , triethylamine , pyridine , nuclear chemistry , organic chemistry , polymer , amino acid , glycine , medicine , pathology , biochemistry , alternative medicine
Copolymerizations of sarcosine‐NCA (Sar‐NCA) with leucine‐NCA (Leu‐NCA) or phenylalanine NCA (Phe‐NCA) were conducted under five different reaction conditions. Benzylamine, triethylamine, pyridine and sodium methoxide (NaOMe) were used as initiators. Molar compositions of the resulting copolypeptides were determined by 1 H or 13 C NMR spectroscopy and reactivity ratios were calculated from copolymerizations stopped at low conversions. Sequence analyses of copolypeptides isolated at high conversions were conducted by means of 13 C or 15 N NMR spectroscopy. Blocky sequences were found due to a higher reactivity of Sar‐NCA under all reaction conditions. The secondary structure of the solid copolypeptides was characterized by 13 C NMR CP/MAS spectroscopy and WAXS powder patterns. The secondary structures are kinetically controlled and change into thermodynamically stable ones upon reprecipitation.