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

Participants

Reaction Steps

To a solution containing 11.6 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 40°-45° C. for 6 hours. Then, the resulting solution was distilled under reduced pressure to remove methanol. The residue was dissolved in 100 ml of dioxane and 200 ml of water. A 20% aqueous sodium carbonate solution was added dropwise to the resulting solution so as to adjust its pH at 7.8 and thereafter further reaction was conducted at 40°-45° C. for 20 hours. Then, the reaction mixture was cooled to room temperature and the crystal thereby deposited was filtered, washed with dioxane and then with water, and dried to obtain 40.6 g of 5-benzyl-3,6-dioxo-2-piperazine acetic acid methyl ester.

Provenance & Evidence