反应详情

温度

-5 °C

A slurry of (S)-3-[[(phenylmethoxy)carbonyl]amino]-2-azetidinone (0.78 g, 3.54 mmole) in dry dichloromethane was warmed briefly to 50° C. and then cooled to -5° C. Triethylamine (0.354 g, 3.54 mmole) and phosgene (5.7 ml of 12.5% phosgene/toluene) were added and the reaction was stirred at -5° C. for 2 hours. The reaction was concentrated to a residue and fresh dichloromethane was added. After the solution was cooled to -50° C., triethylamine (0.714 g, 7.08 mmole) and azetidine-2-carboxylic acid, benzyl ester hydrochloride (0.8 g, 3.54 mmole) were added. The reaction was stirred at -5° C. for 45 minutes. The reaction mixture was poured into 10% monobasic potassium phosphate and the dichloromethane layer was separated and washed with water and brine. After drying over sodium sulfate the solvent evaporated. The crude oil was flash chromatographed on silica (LPS-1) eluting with ethyl/acetate:hexane (1:1). Fractions containing pure compound were concentrated to give 0.622 g of the title compound.

1. concentrationThe reaction was concentrated to a residue and fresh dichloromethane
2. additionwas added
3. temperatureAfter the solution was cooled to -50° C.
4. stirringThe reaction was stirred at -5° C. for 45 minutes
5. customthe dichloromethane layer was separated
6. washwashed with water and brine
7. dry with materialAfter drying over sodium sulfate the solvent
8. customevaporated
9. customchromatographed on silica (LPS-1)
10. washeluting with ethyl/acetate
11. additionFractions containing pure compound
12. concentrationwere concentrated