Stereoregular AABB polyamides

The synthesis of 1,6-diamino-l,6-dideoxy-2,3,4,5-tetra-0-methyl-D-mannitol and its L-iditol analogue from D-mannitol has been described [100], These diamines, containing a two-fold axis, gave stereoregular AABB polyamides on polycondensation with terephthaloyl dichloride and dipentachlorophenyl esters, or dichlorides of aliphatic dicarboxylic acids, in solution or under interfacial polycondensation conditions [99, 109]. In spite of the regioregularity present in the polymeric chains, these optically active polyamides could not be crystallized. 

Mancera M., Roffe 1., Al-Kass S.S.J., Rivas M., Galbis J.A., Synthesis and characterization of new stereoregular AABB-type polyamides from carbohydrate-based monomers having D-manno and L-ido configurations. Macromolecules, 36, 2003,1089-1097. 

Diamino derivatives of carbohydrates have been employed for polycondensation reactions with carboxyl-activated aliphatic and aromatic dicar-boxylic acids. The resulting polyamides are of the AABB type (nylons-m,n analogs), and therefore, the regio- and stereoregularity in the polyamide chain is determined by the configuration of the carbohydrate precursor. When such a molecule lacks a C2 axis of symmetry, random polymerization leads to nonstereoregular polyamides. 

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