反应详情

At room temperature (25° C.) 8.18 g (22.0 mmol) of (3S,4S)-1-carboxymethyl-4-[(1R)-1-(p-chlorophenylthiocarbonyl)ethyl]-3-[(1R)-1-hydroxyethyl]-2-azetidinone was dissolved in 18 ml of dimethylformamide, and 5.5 ml (40.0 mmol) of pivaloyloxymethyl chloride and 5.75 g (40.3 mmol) of sodium iodide were sequentially added thereto. Subsequently, 4.2 ml (25.3 mmol) of diisopropylethylamine was added dropwise thereto, and stirring was performed at the same temperature for 20 hours. The reaction solution was diluted with 120 ml of toluene, and washing was performed several times using 2.5% aqueous sodium bicarbonate and water. The resulting toluene solution was dried over sodium sulfate, and then the solvent was removed by distillation. The resulting oily residue was dissolved in 60 ml of toluene at room temperature, and 120 ml of hexane was added to the toluene solution to precipitate crystals. The resulting crystals were separated by filtration and washed. Thereby, 9.46 g of white crystals of the target compound was produced (yield 92.7%).

1. washwashing
2. dry with materialThe resulting toluene solution was dried over sodium sulfate
3. customthe solvent was removed by distillation
4. dissolutionThe resulting oily residue was dissolved in 60 ml of toluene at room temperature
5. addition120 ml of hexane was added to the toluene solution
6. customto precipitate crystals
7. customThe resulting crystals were separated by filtration
8. washwashed