Synthesis of 2-O-(4-Coumaroyl)-3-(4-hydroxyphenyl)lactic Acid, an Important Intermediate of Rosmarinic Acid Biosynthesis

A simple method to synthesize (±)-2-O-(4-coumaroyl)-3-(4-hydroxyphenyl)lactic acid (1), a key intermediate in rosmarinic acid biosynthesis in higher plant cells, was established by condensation of protected 4-coumaric acid and (±)-3-(4-hydroxyphenyl)lactic acid followed by deprotection. A stable supply of 1 thus attained will lead to biochemical and molecular biological characterization of later steps of rosmarinic acid biosynthesis.