Structure of the Condensation Products of D-Lactose and D-Maltose with SH-Contaning Carboxylic Acid Hydrazides

The structure of the condensation products of D-lactose and D-maltose with sulfanylacetic, 3-sulfanylpropanoic, and 2-sulfanylbenzoic acid hydrazides has been studied 1H and 13C NMR spectroscopy. The condensation products obtained from the disaccharides and sulfanylacetohydrazide and 3-sulfanylpropanehydrazide have pyranose structure in the crystalline state, whereas those derived from 2-sulfanylbenzohydrazide have cyclic 1,3,4-benzothiadiazepine structure in crystal. All condensation products in solutions in most solvents (D2O, DMF-d7, DMSO-d6) exist as equilibrium mixtures of linear and cyclic pyranose and 1,3,4-benzothiadiazepine tautomers.