| Abstract: | 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 polyN-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 δG? values for Cis-trans isomerization in these amides were 18 ～ 19 kcal/mole, which were virtually the same as that of polysacrosine. |
