A Novel Yellow Compound and Furpipate Derivatives Formed from Furfural or 5-Hydroxymethylfurfural in the Presence of Lysine

Furfural and 5-hydroxymethylfurfural (HMF) are important intermediate compounds in the Mail-lard reaction of pentose and hexose, respectively, under acidic conditions. Recently we found a novel yellow compound named furpipate from a heated solution containing furfural and lysine. Here we describe the formation of furpipate derivatives in a heated solution containing furfural or HMF in the presence of lysine. Three derivatives, decarboxylated-furpipate, 5-hydroxymethylfurpipate, and decarboxylated5-hydroxymethylfurpipate, were isolated and identified. 5-Hydroxymethylfurpipate, (Z )-3-[2-(5-hydoxymethyl-furylmethylidene]-3H, 4H, 5H, 6H-pyridine-2-carboxylic acid, is a novel compound and the major yellow pigment of the heated solution containing HMF and lysine.