Triethylamine → HCID 178501405, compound

Participants

Reaction Steps

To a suspension of 3.00 g of (±)-2-(1-naphthylmethyl)-3-(phenethylcarbamoyl)propionic acid and 2.01 g of L-histidine methyl ester dihydrochloride in 24 ml of N,N-dimethylformamide were added successively 2.16 ml of diphenylphosphoryl azide and 3.81 ml of triethylamine under ice-cooling, and the mixture was stirred for 16 hours under ice-cooling. The reaction mixture was evaporated under reduced pressure, and a 5% aqueous sodium bicarbonate solution was added to the residue. The mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with water, dried over anhydrous magnesium sulfate, and evaporated under reduced pressure. Diethyl ether was added to the residue, the precipitated crystals were collected by filtration to obtain 4.08 g of N-[(±)-2-(1-naphthylmethyl)-3-(phenethylcarbamoyl)propionyl]-L-histidine methyl ester as a white powder. To a solution of 4.00 g of the ester compound obtained in 25 ml of methanol was added 2.75 g of hydrazine monohydrate, and the mixture was stirred for 4 hours at room temperature. The reaction mixture was evaporated under reduced pressure. The residue was washed with diethyl ether, and dried under reduced pressure below 40° C. to obtain 3.90 g of N-[(±)-2-(1-naphthylmethyl)-3-(phenethylcarbamoyl)propionyl]-L-histidine hydrazide as a white powder. In 5 ml of methanol was dissolved 2.20 g of the hydrazide compound obtained with heating at 40° C., and insoluble materials were filtered off. The filtrate was allowed to stand overnight at room temperature, and then precipitated crystals were collected by filtration to obtain 0.70 g of N-[(±)-2-(1-naphthylmethyl)-3-(phenethylcarbamoyl)propionyl]-L-histidine hydrazide as a white powder.

Provenance & Evidence