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Nuclear magnetic resonance study on the model compounds for poly( N ‐alkylglycine)s
Author(s) -
Sisido Masahiko,
Imanishi Yukio,
Higashimura Toshinobu
Publication year - 1973
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.1973.360121015
Subject(s) - chemistry , isomerization , methylene , benzene , alkyl , kinetics , cis–trans isomerism , population , nuclear magnetic resonance spectroscopy , medicinal chemistry , stereochemistry , organic chemistry , catalysis , physics , demography , quantum mechanics , sociology
Cis ‐ trans isomerism was investigated with N ‐acetyl and N ‐propionyl, N ‐alkylglycine dimethylamides as model compounds for poly( N ‐alkylglycine dimethlamides as model compounds for ( N ‐alkylglycine)s using n.m.r. spectroscopy. The population of the cis isomer measured in benzene and methylene chloride solutions did not show any marked dependence on the bulkiness of N ‐alkyl substituents. This contrasts with poly N ‐alkylglycine)s, whose cis isomer population increased with the introduction of bulky N ‐alkyl groups. Kinetics of the Cis ‐ trans isomerization was also investigated with N ‐acetyldimethylamides of sacrosine, N ‐ n ‐propylglycine, and N ‐isopropylglycine in tetrachloroethane solution. The δ G ‡ values for Cis ‐ trans isomerization in these amides were 18 ∼ 19 kcal/mole, which were virtually the same as that of polysacrosine.