L-Pyroglutamic Acid → HCID 14053691, compound

Participants

Reaction Steps

Pyroglutamic acid (112.4 g), 147.7 g of N-carbobenzoxypiperazine, 179.7 g of dicyclohexylcarbodiimide and 6.7 liters of acetonitrile were heated to reflux for 6 hours with stirring. The insoluble matters were removed by filtering the reaction mixture and the solvent was evaporated from the filtrate in vacuo. The residue was subjected to a silica gel column chromatography to give 190 g of oily N-carbobenzoxy-N'-(2-pyrrolidon-5-carbonyl)piperazine. Thirty grams of this was dissolved in 450 ml of methanol and the solution was subjected to a catalytic reduction using 3.0 g of 5% palladium-carbon with stirring at room temperature. The catalyst was removed by filtering the reaction solution and the solvent was evaporated in vacuo from the filtrate to give 20 g of the product. This was recrystallized from a mixture of methanol and ethyl acetate to give 17.5 g of desired compound, m.p. 162°-163° C.

Provenance & Evidence