Highly efficient synthesis of capsaicin analogues by condensation of vanillylamine and acyl chlorides in a biphase H2O/CHCl3 system

Highly efficient synthesis of capsaicin analogues was developed using condensation of vanillylamine with acyl chlorides in a biphase H2O/CHCl3 system under mild conditions. For C4–C18 aliphatic or aromatic acyl chlorides, the yields were up to 93–96% with high purity after a simple work-up procedure, and only 1–1.16equiv of acyl chloride was needed in the reaction.