反应详情

A suspension of 2 g of poly-Hunig base in 8 ml of dioxan is stirred for 30 minutes at room temperature, 832 mg of 2-[(3S,4R)-4-acetylthio-3-methoxy-2-oxoazetidin-1-yl]-2-hydroxyacetic acid p-nitrobenzyl ester dissolved in 12 ml of dioxan are added and then slowly a solution of 0.54 ml of thionyl chloride in 10 ml of dioxan is added. The mixture is stirred for 2 hours at room temperature, the poly-Hunig base is filtered off and the filtrate is concentrated by evaporation in vacuo. The residue is purified by chromatography over silica gel with toluene/ethyl acetate (1:1) and yields the 2-[(3S,4R)-4-acetylthio-3-methoxy-2-oxoazetidin-1-yl]-2-chloroacetic acid p-nitrobenzyl ester in crude form.

1. additionare added
2. stirringThe mixture is stirred for 2 hours at room temperature
3. filtrationthe poly-Hunig base is filtered off
4. concentrationthe filtrate is concentrated by evaporation in vacuo
5. customThe residue is purified by chromatography over silica gel with toluene/ethyl acetate (1:1)