Hydrochloric Acid → 5-Benzyl-3,6-dioxo-2-piperazine acetic acid methyl ester

Participants

Reaction Steps

To a solution having 9.6 g of hydrogen chloride dissolved in 400 ml of methanol was fed 61.6 g of N-formyl-α-L-aspartyl-L-phenylalanine and the resulting mixture was reacted at 50°-60° C. for 6 hours. The resulting reaction solution was cooled to room temperature, added dropwise with 30.4 g of triethylamine, and then subjected to further reaction under reflux for 8 hours. The reaction mixture was cooled to room temperature and the crystal thereby deposited was filtered and washed with methanol to obtain 40.2 g of 5-benzyl-3,6-dioxo-2-piperazine acetic acid methyl ester having a melting point of 216°-218° C.

Provenance & Evidence