Copper and vanadium complexes of polyhydroxy-compounds. Reactions of carbohydrate derivatives, with enamines

Abstract

Certain polyhydroxy-compounds were found to form cationic complexes with basic copper acetate Cu(CH3COO)2CuO6H2O and the relationship between the conformations of these compounds and their ionophoretic mobilities in basic copper acetate solution was studied. It was established that the mobilities of the reduced glucose disaccharides varied according to whether the glucose units were a- or B-linked, thus affording a method for determining the configuration of the glucosidic linkage in the original disaccharide.The complexing of polyhydroxy-compounds with the oxy-anions present in acidified solutions of sodium metavanadate, NaVO3, and sodium orthovanadate, Na3V04, 14H2O, was explored. Some correlations were drawn between the conformations of cyclic and acyclic polyols and their ionophoretic mobilities in sodium metavanadate solution. Prom polarimetric and absorptiometric measurements, the stoicheiometry of a number of complexes was determined, while the nature of the complexing vanadate ion was investigated by potentiometric and conductimetric titrations of solutions of sodium metavanadate and orthovanadate containing D-glucitol and D-mannitol. The number of hydroxyl groups in D-glucitol involved in the complexing was derived from periodateoxidation of the complex.The polarimetric method developed to establish the stoicheiometry of complexes between sodium metavanadate and polyhydroxy-compounds was applied to the equilibrium complexes formed between sodium tungstate and some cyclic sugars.The preparation of a sugar derivative in which the sugar is linked directly, by a carbon-carbon bond, to a cyclic ketone was undertaken. The synthesis was achieved by acylation of an enamine of the cyclic ketone by an acid chloride. Various analytical techniques were used to establish the structure of the product. Other methods of forming such derivatives through the intermediate participation of enamines are briefly discussed.