SYNTHESIS AND PROPERTIES OF STEREOREGULAR POLYAMIDES DERIVED FROM L-TARTARIC ACID - POLY[(2S,3S)-2,3-DIMETHOXYBUTYLENE ALKANAMIDE]S

The synthesis of (2S,3S)-(-)-2,3-dimethoxy-1,4-butanediamine to be employed in the preparation of stereoregular polyamides 4,n containing two chiral carbons in the diamine repeating unit has been carried out by using L-tartaric acid as a raw material. Polycondensation in a chloroform solution of this diamine activated as the N,N'-bis(trimethylsilyl) derivative with pentachlorophenyl esters of even aliphatic diacids ranging from 4 to 12 carbons afforded the title polyamides with DP(n) in the range 20-100 depending upon the value of n. They were characterized by elemental analysis, IR and H-1/C-13 spectroscopies, and powder X-ray diffraction. These highly crystalline polyamides melted in the range 150-190-degrees-C, had a pronounced affinity to water, and exhibited moderate optical activity. All these properties were investigated in relation to the molecular structure and compared with those observed for their isomeric poly[alkylene 2,3-di-O-methyl-L-tartaramide]s, on which we have recently reported in detail.