m-Chloroperbenzoic acid → 1-(4-Fluoro-2-methylaminophenyl)-2-methylsulphonylethanone

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Reaction Steps

A solution of 3-chloroperoxybenzoic acid (8.29 g) in dichloromethane (200 ml) was added to a solution of 1-(4-fluoro-2-methylaminophenyl)-2-methylsulphinylethanone (10.0 g), prepared in a similar manner to that described in Example 1, in dichloromethane (175 ml) over a period of 7 minutes whilst maintaining the temperature below 30°. The mixture was stirred at ambient temperature for 2 hours, saturated aqueous sodium hydrogen carbonate solution (244 ml) was added and the mixture stirred at ambient temperature for a further 2 hours. The dichloromethane layer was isolated and the aqueous layer extracted with dichloromethane (2×60 ml). The organic phases were combined, dried (magnesium sulphate) and evaporated in vacuo to give a solid which was crystallised from acetone to give 1-(4-fluoro-2-methylaminophenyl)-2-methylsulphonylethanone, m.p. 143.5°-145°.

Provenance & Evidence