L-3-Caruboxy-6, 7-dihydroxy-1-methyl-1, 2, 3, 4-tetrahydroisoquinoline from Blackened Sake-cake

Abstract

A new imino acid, one of the precursors of the brown pigment, was isolated from blackened sake-cake by alumina and Dowex55-X8 (H) column chromatography and thinlayer chromatography. Based on NMR, IR and UV spectral data, it was identified as L-3-carboxy-6, 7-dihydroxy-1-methyl-1, 2, 3, 4-tetrahydroisoquinoline and its structure was also confirmed by synthesis. It was suggested that this compound was produced yb the condesation of L-DOPA with acetaldehyde in sake-cake.