反応 #54376

反応方程式

toluene ethyl acetate

2-[4-(benzoxazol-2-yldithio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-methylene-butyric acid diphenylmethyl ester

ozone

O2 O3

→

2-[4-(Benzoxazol-2-yldithio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-hydroxy-crotonic acid diphenylmethyl ester

溶媒

ethyl acetate

反応条件

後処理

1. 1
   濃縮The solution is concentrated by evaporation to about 50 ml in vacuo
2. 2
   workup.ADDITIONmixed with 5 ml of dimethyl sulphide
3. 3
   その他no longer gives
4. 4
   その他a reaction
5. 5
   濃縮The mixture is concentrated by evaporation in vacuo
6. 6
   workup.DISSOLUTIONthe residue is dissolved in 150 ml of benzene
7. 7
   洗浄the solution is washed with water
8. 8
   乾燥The organic phase is dried over sodium sulphate
9. 9
   濃縮concentrated by evaporation
10. 10
    その他The residue is chromatographed on 150 g of acid-washed silica gel

実験手順

(aix) Approximately one equivalent of ozone (in the form of an O2 /O3 mixture) is passed into a solution, cooled to -70° C., of 3.35 g of 2-[4-(benzoxazol-2-yldithio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-methylene-butyric acid diphenylmethyl ester in 125 ml of ethyl acetate, until starting material is no longer detectable by thin layer chromatography (silica gel; toluene/ethyl acetate, 3:1). The solution is concentrated by evaporation to about 50 ml in vacuo, mixed with 5 ml of dimethyl sulphide and stirred until the potassium iodide/starch test no longer gives a reaction. The mixture is concentrated by evaporation in vacuo, the residue is dissolved in 150 ml of benzene and the solution is washed with water. The organic phase is dried over sodium sulphate and concentrated by evaporation. The residue is chromatographed on 150 g of acid-washed silica gel, using toluene/ethyl acetate, 4:1. 2-[4-(Benzoxazol-2-yldithio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-hydroxy-crotonic acid diphenylmethyl ester is obtained in the form of a white foam; IR spectrum (methylene chloride): characteristic bands at 5.60, 5.90 and 6.0 μ.

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