CRYSTAL AND MOLECULAR-STRUCTURES OF D-GLYCERO-L-GULO-HEPTITOL, MESO-GLYCERO-ALLO-HEPTITOL, AND MESO-GLYCERO-ALLO-HEPTITOL HEPTAACETATE

The molecular structures of the title compounds were determined by X-r ay crystallography, using direct methods, and refined to final residua l parameters of R = 0.040, 0.063, and 0.044, respectively. All the com pounds investigated adopt bent conformations, the molecules of meso co nfiguration thus becoming chiral conformers. For meso-glycero-allo-hep titol, this involves a 1,3-parallel interaction between C-5 and O-2. T he derived heptaacetate is found in a different conformation with O-3/ C-6 and O-4/C-7 aligned 1,3-parallel. The reported solution for meso-g lycero-allo-heptitol is conventional, but with regard to the optimum i n crystallography has to be considered as preliminary.