Amino-carbonyl carbohydrates interactions with substituted aromatic amines

The syntheses of the amino-carbonyl reaction nitrogenous products of D-glucose with substituted aromatic amines, containing functional donor and acceptor functional groups: p-toluidine, m- and p-aminobenzoic acids are submitted, comparative amines and amino-conjugates activity at the different stages of the Maillard reaction is analyzed. Synthesis was carried out direct condensation of compounds D-glucose with substituted aromatic amines in non-absolute ethanol in an equimolar ratio carbohydrate and amine reaction products was isolated, purified, dried, and characterized. The N-glycosylamines synthesized are white crystalline solids, sparingly soluble in water, slightly soluble in ethanol, practically nonproliferation-soluble in ether. Correlation of amines basicity with their reactivity on the different glycosylation reaction stages is confirmed, inability to obtain acceptable yield of Amadori rearrangement products in the cases of weakly basic carboxyphenyl aglicones glycosylamines is marked. Only the previously known p-TGPA-rearrangement product (1-deoxy-1-p-toluidino-D-fructose) was isolated in the crystalline state and identified based on the measurement data of melting points and IR-spectra. Valuation of the relative lability of N-glycosylamines to melanoidines formation is given by spectrophotometry. Formation of colored products during intense heating with D-glucose in alcohol solution under conditions of acid catalysis is mentioned for all amines; the activity in the reactions, estimated by spectrophotometry, also maximal for p-toluidine, which can be associated again with its higher basicity, which facilitates the formation of a number of stages melanoidins. To estimate the relative amino-conjugates stability and their ability to melanoidines formation electronic spectra of the reaction mixtures were taken in the wavelength range of 300-400 nm. No absorption in the visible region for systems with aminobenzoic acids confirms implementation difficulties acid-catalyzed rearrangement accumulates relatively stable in the reaction conditions carboxyphenylglycosylamines in accordance with the velocities of their formation, and an appreciable melanoidins in these conditions is observed. In contrast, weak base conjugates significant accumulation of p-TGPA does not occur, it is formed intensively in the reaction system, followed by rearrangement, followed by a gradual degradation of the Amadori rearrangement products to form colored compounds, exhibiting absorption in the visible region in the form of characteristic for melanoidins absorption peak as a plateau.