| Abstract: | Stereoregular, enantiomerically pure, chiral polyamides of the –AB– type, containing a natural (glycine) and a synthetic (S)-5-amino-4-methoxypentanoic acid (AMP)] component have been prepared by the active ester polycondensation method. Thus, polyamide 7 was obtained by polycondensation of the conveniently activated H2NGly–AMPCO2R unit ( 6 ). In this reaction, 7 appeared accompanied by a considerable amount of cyclic (Gly–AMP)2 ( 8 ), which makes the isolation and purification of 7 difficult. The formation of cyclic byproducts could be avoided by preparing and polymerizing the oligoamide H2NGly–AMP–AMPCO2R ( 11 ), which has the terminal carboxyl group activated as the pentachlorophenyl ester. The resulting polyamide ( 12 ) was obtained in 85% yield and free of macrolactams, such as 8 . The new polyamides 7 and 12 were characterized by elemental analysis and infrared and 1H- and 13C-nuclear magnetic resonance spectroscopies. Thermal studies revealed that 12 is crystalline and yields films with spherulitic texture by slow evaporation of formic acid solutions. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2741–2748, 1998 |
