Conformational studies of diosgenyl 2-amino-2-deoxy-β-D-glucopyranosides at the PM3 and DFT levels of theory.

Geometry optimizations at the PM3 level were performed for diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside and its N-protonated form. Next, B3LYP/6-311++G(**) level geometry optimizations were carried out, albeit on a simpler model. The relative Gibbs free energies and geometry parameters are presented for the optimized structures.

DFT studies of the conversion of four mesylate esters during reaction with ammonia.

The energetics of the Menshutkin-like reaction between four mesylate derivatives and ammonia have been computed using B3LYP functional with the 6-31+G** basis set. Additionally, MPW1K/6-31+G** level calculations were carried out to estimate activation barrier heights in the gas phase. Solvent effect corrections were computed using PCM/B3LYP/6-31+G** level.