A New Synthesis of (±)-Trypargine

Abstract

A new route for the synthesis of (±)-trypargine (I) is described. The Pictet-Spengler reaction of N_b-benzyltryptamine with α-ketoglutaric acid was carried out in aprotic media to afford the key intermediate, 2-benzyl-1, 2, 3, 4-tetrahydro-9H-pyrido [3, 4-b] indole-1-propionic acid (IIa), which was converted into (±)-trypargine (I) in five or six steps.