4-Methylmorpholine → HCID 178454158, compound

Participants

Reaction Steps

1.99 g of N-t butoxycarbonyl-L-phenylalanine and 1.58 g of benzyl (S)-α-hydroxyimidazolepropionate were suspended in 25 ml of methylene chloride and stirred. After stirring at room temperature for 15 minutes, 305 mg of 4-dimethylaminopyridine were added and the reaction mixture was cooled to -15°. After the dropwise addition of 2 ml of N-methylmorpholine and a solution of 6.6 g of propanephosphoric acid anhydride in 5 ml of methylene chloride, the reaction mixture was stirred at -15° for an additional 2 hours and left to stand at -18° for 6 days. After the addition of a few drops of water, the reaction mixture was evaporated under reduced pressure and the oily residue was triturated for 2 hours with 100 ml of ethyl acetate and 25 ml of water. The organic phase was then washed in succession with aqueous sodium bicarbonate solution (5%) water and 1.5M citric acid. The colorless oil obtained after evaporation of the solvent under reduced pressure was chromatographed on silica gel using a 95:5 mixture of methylene chloride and methanol as the eluting agent, to obtain (S)-α-[[N-(t-butoxycarbonyl) 3-phenyl-L-alanyl] oxy]imidazole-4-propionic acid benzyl ester as a yellow oil in 13% yield, MS: 494 (M+H)+.

Provenance & Evidence