m-Chloroperbenzoic acid → 2-(2-Hydroxyethanesulphinyl)-4,5-bis-(p-methoxyphenyl)-thiazole

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Reaction Steps

5.0 g of 2-(2-hydroxyethylthio)-4,5-bis-(p-methoxyphenyl)-thiazole are dissolved in 100 ml of methylene chloride and, while stirring, 2.56 g of m-chloroperbenzoic acid are added in portions. The mixture is then stirred for 15 minutes and subsequently extracted by shaking twice with dilute sodium carbonate solution. The aqueous phase is then washed with methylene chloride. The organic phases are combined, dried over magnesium sulphate and concentrated to dryness by evaporation. The crude product is dissolved in 10 ml of ethyl acetate, precipitated with 30 ml of diethyl ether, filtered with suction, washed with diethyl ether, dried under reduced pressure and, to purify further, made into a slurry with 50 ml of diethyl ether, filtered again and dried at 0.01 mbar and 100° to constant weight. 2-(2-hydroxyethanesulphinyl)-4,5-bis-(p-methoxyphenyl)-thiazole is obtained in the form of a pale yellow oil, Rf value 0.12 (silica gel thin layer/toluene:ethyl acetate 1:1); IR-spectrum: νSO =1060 cm-1 (3% in CH2Cl2).

Provenance & Evidence