MEDIA EFFECTS IN THE NON-ENZYMATIC BROWNING REACTIONS IN CARBOHYDRATE-ARYL AMINE SYSTEMS
Specification of amino-carbonyl interactions mechanisms in aqueous-ethanolic systems carbohydrate-aryl amine in the conditions of acid catalysis by acetic and sulfuric acids is carried out. On the bases of spectroscopy and elemental analysis data the tendency of monosaccharides, larger in comparison with disaccharides, to formation of nitrogen free reductones, which nature and structure in essential degree is defined by composition of solvent and type of acid catalyst is shown. In the reactions catalyzed by an acetic acid the mechanism of formation condensation of reductones (3-desoxysones) which further transformations can be realized in several directions is implemented. Ring formation with the subsequent dehydration or solvolytic α-dicarbonyl cleavage is lead to formation of low-molecular derivants of furan, capable to direct condensation, at the same time increase of ethanol content as a part of solvent reduces a yield of the last. The second direction supposes aldol type condensation in combination with the ring formation leading to polymethylenfuran and polymethinfuran structures. The free aerated media assume a possibility of oxidation the carbohydrate’s endiols with formation of ozones which solvolytic α-dicarbonyl cleavage in total with a direct destruction also are proved, at the same time the part of the last group’s processes is higher in a case in systems on monosaccharide’s base in highly-ethanolic solvents. In systems with sulfuric acid some differences in structure of products are observed, in particular partial transformation of furan heterocycles in aromatic structures of other class is noted. It should be noted, that in systems with sulfuric acid as the catalyst generally dialyzable low-molecular fractions are formed, it is possibly due to influence of ethanol on condensation processes. It is quite probable that the reactionary media in this case deactivates aryl amine, suppressing amino-carbonyl condensation, and process proceeds as a direct destruction of carbohydrate.