Synthesis and characterization of stereoregular AABB-type polymannaramides

The condensation of D-mannaro-1,4:6,3-dilactone (2) with even-numbered alkylenediamines (C-2, C-6-C-12) in a methanol solution and in the presence of triethylamine afforded polymannaramides 3-7, which were isolated directly as white solids with various hydrophobic-hydrophilic characters. Because all the stereocenters in 2 possessed an S configuration, the random polymerization led to optically active, stereoregular polyhydroxypolyamides. The polymers were characterized by elemental analysis and IR, H-1 NMR, and C-13 NMR spectroscopy. Their number-average molecular weights were estimated by H-1 NMR spectral integration analysis. Thermal and powder X-ray diffraction studies revealed that compounds 3-7 were poorly crystalline. (C) 2001 John Wiley & Sons, Inc.