THE METHOD OF OXIDATION AND THE OXIDATION PRODUCTS OF l-ARABINOSE AND OF l-XYLOSE IN ALKALINE SOLUTIONS WITH AIR AND WITH CUPRIC HYDROXIDE.¹

Abstract

Nef published his first work on the oxidation of sugars by Fehling's solution, or, more correctly, by a suspension of cupric hydroxide in an alkaline sugar solution, in Liebig's Annalen in 1907.~ The sugars studied were I-arabinose, d-glucose, d-mannose and d-fructose. Thereafter a series of investigations was undertaken by Nef, in part in collaboration with his students.3 The present work was undertaken in order to obtain more complete information with regard to the amounts of the oxidation products. Experimental proof of the production of certain acids, such as ribonic acid, was sought for. When I-arabinose was oxidized in alkaline solutions by air, E-erythronic, d-threonic, d-and I-glyceric, glycollic, formic and carbonic acids were produced. When oxidation was accomplished by cupric hydroxide, I-arabonic, I-glyceric, glycollic, oxalic, formic and carbonic acids were found among the oxidation products: 1-Ribonic acid was not found, although it was presumably produced, for d-lyxonic acid was found among the oxidation products of 1-xylose. Other products of oxidation of 1arabinose were obtained by Nef in former experiment^.^ When I-xylose was oxidized in alkaline solutions by air, I-threonic, d-erythronic, I-glyceric, glycollic, formic and carbonic acids were found to be present among the products. When oxidation was accomplished 1 The experimental work described in this paper was done by Dr. Nef during the two years previous to his death on August 13, 1915, with the assistance of Dr. Glattfeld and myself. I have undertaken to prepare the results of t h e work of this period for publication. Dr. Glattfeld has assisted in the preparation of this paper.-Oscar F. Hedenburg.

Sugar Fragmentation in the Maillard Reaction Cascade: Formation of Short-Chain Carboxylic Acids by a New Oxidative α-Dicarbonyl Cleavage Pathway

“…The degradation of sugars to low molecular weight compounds has been widely studied in aqueous alkaline solutions ( − ) and in the presence of amines ( − ), basically resulting in carboxylic acids (e.g., lactic, glycolic, formic, acetic, pyruvic, erythronic, threonic, and saccharinic acids) and carbonyl compounds (e.g., methylglyoxal, acetol, reductones, and 2,3-butanedione). There are three main reaction mechanisms operating in most instances: (i) benzilic acid type rearrangement, (ii) retro-aldol cleavage, and (iii) splitting of dicarbonyl intermediates.…”

Preparation of lower aldonic acids by oxidation of sugars in alkaline solution

“…The yield, approximately 45 percent, is somewhat higher than tha.t obtained by N ef, Hedenberg, and Glattfeld [5] from the oxidation of d-xylose with air.…”

“…The crystals on the filter were washed with 10 ml of absolute alcohol, and the filtrate and washings were used to extract the second crop (mp, 115° C), with the result that the melting point was raised to 200° C. The crystalline fractions which remained at this point melted above 200° C and had a combined weight of 18.7 g. By recrystallization from hot ethyl alcohol (600 ml) and concentration of the mother liquors, a total of ] 3 g of substantially pure brucine l-erthyronate was obtained. 4 The yieJd of brucine l-erythronate, 43 percent, was only slightly higher than that obtained by Nef, Hedenberg, and Glattfeld [5] by oxidation of l-arabinose with air.…”

Electrolysis of low molecular weight carbohydrates in non-aqueous media. I. The products of electrolysis of monosaccharides

“…Neuberg's (14) discovery of ozones in the electrolysis of aldoses may mean that an a-keto compound is formed (34) either prior to, or after, the carboxyl group, thus giving an v.-ketoaldonic acid which can decarboxylate to an aldose having one less carbon atom (35). Consistent with such a theory are the alkaline oxidative degradation of Dglucose to D-arabonic acid (36) and barabinose to ~~e r y t h r o n i c acid (37), the formation in alkali of carbonyl derivatives of carboxylic acids (31), and the detection of a keto acid from the electrolysis of erythronic acid (21). If such acidic intermediates participate in these reactions the aldoses must be strongly favored in any equilibria involving the oxidized compounds, and/or the oxidation must be very slow relative to decarboxylation so that at any instant the concentration of the intermediate is below present levels of detection.…”