MM3(96) CONFORMATIONAL ANALYSIS OF D-GLUCARAMIDE AND X-RAY CRYSTAL STRUCTURES OF THREE D-GLUCARIC ACID DERIVATIVES-MODELS FOR SYNTHETIC POLY(ALKYLENE D-GLUCARAMIDES)

摘要

An exhaustive conformational analysis of D-glucaramide was carried out using MM3(96) [MM3(96). Molecular Mechanics Software used with permission from N.L. Allinger; University of Georgia]. Nine torsion angles were each driven in increments of 120 deg C, generating 19,683 starting conformations. Each conformation was then fully energy-minimized using MM3's block diagonal/full matrix optimization option at dielectric constants of both 3.5 and 6.5. Conformer populations were calculated based on the modeling results and calculated theoretical average ~1H vicinal coupling constants were compared to experimental values obtained in D_2O solution. Crystal structures of three acyclic D-glucaric acid derivatives (N,N'-dimethyl-D-glucaramide, dipotassium D-glucarate, and sodium potassium D-glucarate) are reported. These structures and that of previously reported monopotassium glucarate correspond closely with model conformations that were within one kcal/mol of the global minimum.