Interpretation of some reactions in the carbohydrate field in terms of consecutive electron displacement

Abstract

An attempt has been made to show how the concept of consecutive electroll displacement that has been developed in recent years may be used for the interpretation of certain reactions in the carbohydrate field. The viewpoint in general is that the peculiar properties of systems involving double bonds may be explained by the migration of electron pairs in the molecule from points of high electron density to points of lower electron density, with the addition and elimination of ions. A number of apparently unrelated complex reactions of the carbohydrates are considered and it is shown that the formation of the products may be explained by a few simple reactions involving shifts of electron pairs; these include enolization, de-enolization and double decomposition. Mechanisms are presented for the formation of the four classes of saccharinic acids from the 1,2-, the 2,3-, and the 3,4-enediols, for the formation of diacetylkojic acid from acetylgluco-sone, for the formation of unsaturated lactones from hydroxy acids, for the conversion of triacetylgucal to diacetylpseudoglucal, for the conversion of tetramethyl-1, 2-glucoseen to w-methoxymethylfurfural, and for the formation of furfural and levulinic acid. CONTENTS Page I. Int roduction _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 45 II. Formation of saccharinic acids by the action of alkali on sugars_ _ _ _ _ _ 47 III. Formation of diacetylkojic acid from acetylated glucosone hydrate_ ___ 50 IV. Formation of unsaturated lactones from hydroxy acids _ _ __ _ __ _ _ __ __ _ 51 V. Conversion of triacetylglucal to diacetylpseudoglucaL _ _ _ _ _ _ _ _ _ _ _ _ _ _ 52 VI. Conversion of pseudoglucal to isoglucal and protoglucaL _ _ _ _ _ _ _ _ _ _ _ 53 VII. Conversion of tetramethyl-1,2-g1ucoseen to w-methoxymethylfurfuraL _ 54 VIII. Formation of furfural from trimethylpentoses_ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 55 IX. Formation of levulinic acid from w-hydroxymethylfurfural and from 2-desoxypentoses__ __ __ ________________________ _____ __________ 57 X. References__ _______________________________________ _______ __ __ 59