反应详情

(avii) 1.08 g (3 mmols) of tetrabutylammonium iodide and 1.9 ml (2.52 g, 20 mmols) of dimethylsulphate are added to a suspension of 3.36 g (5 mmols) of 2-[4-(p-toluenesulphonylthio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-hydroxy-crotonic acid diphenylmethyl ester (crystalline) in 15 ml of carbon tetrachloride and 10 ml of water. The mixture is vigorously stirred at room temperature and 1 N sodium hydroxide solution is added to it by means of an automatic titrator in sufficient amount to keep the pH constant at 7.0. In the course of 4-5 hours, 1.5-2 equivalents of sodium hydroxide solution are consumed. The mixture is diluted with ethyl acetate and water and a little sodium chloride is added. The organic phase is dried over sodium sulphate and concentrated by evaporation. The residue is crystallised from a little ethyl acetate/hexane, 1:1, and gives 2-[4-(p-toluenesulphonylthio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-methoxy-iso-crotonic acid diphenylmethyl ester.

1. dry with materialThe organic phase is dried over sodium sulphate
2. concentrationconcentrated by evaporation
3. customThe residue is crystallised from a little ethyl acetate/hexane, 1:1