Synthesis of pyrraline reference material.

A simplified and improved method is described for the preparation of pyrraline, a lysine derivative from the advanced Maillard reaction and potential indicator for heat treatment of foods. The compound was obtained in a high degree of purity and with a yield of 31% from N alpha-t-butyloxycarbonyl-L-lysine after heating with 3-deoxy-D-erythro-hexos-2-ulose for 2 h at 70 degrees C in the dry state, preparative fractionation of the resulting N alpha-t-butyloxycarbonyl pyrraline with reverse-phase liquid chromatography and final deprotection of the intermediate compound with acetic acid.