Patent ID: 6841183

Claim:
A process for producing a N-[N-[3-(2-hydroxy-substituted phenyl)propyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester compound represented by formula (2), said process comprising: subjecting a 2-hydroxychroman compound represented by formula (1) and aspartame to a reductive alkylation reaction, to obtain said N-[N-[3-(2-hydroxy-substituted phenyl)propyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester compound: wherein in formulas (1) and (2), R 1 , R 2 , R 3 , and R 4 , independently from each other, each represent a substituent selected from the group consisting of a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 3 carbon atoms, a benzyloxy group, an alkyl group having 1 to 3 carbon atoms, and a hydroxyalkyloxy group having 2 or 3 carbon atoms, and wherein R 1 and R 2 together, R 3 and R 4 together, or R 2 and R 3 together may represent a methylenedioxy group, with the proviso that in formula (2), none of R 1 , R 2 , R 3 and R 4 represents a benzyloxy group.