3-Methyl-2(1H)-pyrazinones, the Asparagine-Specific Maillard Products Formed from Asparagine and Monosaccharides

Article abstract of DOI:10.1021/jf00051a040

Four unknown compounds from the reactions of monosaccharides and asparagine have been positively identified by spectroscopic elucidation and synthesis as 3,5-dimethyl-6-ethyl-2(1H)-pyrazinone, 3,6-dimethyl-5-ethyl-2(1H)-pyrazinone, 3,5,6-trimethyl-2(1H)-pyrazinone, and 3-methyl-5,6-diethyl-2(1H)-pyrazinone, which are novel to model reaction studies.This group of compounds can be recognized as asparagine-specific Maillard products.The formation mechanism of them has been proposed.Basically, 3-aminosuccinimide, asparagine, and isoasparagine may be at an equilibriumstate.Condensation of isoasparagine and α-dicarbonyls (the degradation products of the monosaccharide) leads to the formation of 3-(carboxymethyl)-5,6-dialkyl-2(1H)-pyrazinones, decarboxylation of which generates 3-methyl-5,6-dialkyl-2(1H)-pyrazinones.Identification of this group of compounds from Maillard reaction was herein reported for the first time in literature.Keywords: Asparagine; fructose; glucose; rhamnose; alkylpyrazines; Maillard reaction; 3,6-dimethyl-5-ethyl-2(1H)-pyrazinone; 3,5-dimethyl-6-ethyl-2(1H)-pyrazinone; 3,5,6-trimethyl-2(1H)-pyrazinone; 3-methyl-5,6-diethyl-2(1H)-pyrazinone; 3,6-dimethyl-5-propyl-2(1H)-pyrazinone; 3,5-dimethyl-6-propyl-2(1H)-pyrazinone