反应详情

温度

-65 °C

To a solution of methyl α-[4-mercapto-3-phthalimido-2-oxoazetidin-1-yl]-α-(1-hydroxyethylidene)acetate (100 mg) in tetrahydrofuran (3 ml) is added benzyl chloroformate (100 mg), and the mixture is cooled to -65° C. To the solution is added triethylamine (60 mg) and stirred for 1 hour. After warming to room temperature, the mixture is evaporated. Purification of the residue by chromatography over silica gel gives methyl α-[4-benzyloxycarbonylthio-3-phthalimido-2-oxoazetidin-1-yl]-α-(1-benzyloxycarbonylethylidene)acetate (160 mg). Yield: 94%. The product contains no isomer at position α, IR: νmaxCHCl3 1790, 1780, 1730 cm-1. NMR: δCDCl3 8.00.varies.7.50m4H, 7.40s5H, 7.30s5H, 6.27d(5 Hz)1H, 5.90d(5 Hz)1H, 5.27s2H, 5.17s2H, 3.70s3H, 2.47s3H.

1. temperatureAfter warming to room temperature
2. customthe mixture is evaporated
3. customPurification of the residue by chromatography over silica gel