Phenol → 2-(4-Hydroxyphenyl)-2,4-dimethyl-2H-1,4-benzothiazin-3(4H)-one

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Reaction Steps

To a stirred solution of 3,4-dihydro-2,4-dimethyl-3-oxo-2H-1,4-benzothiazine (4.8 g) in methylene chloride (25 ml), sulfuryl chloride (3.5 g) is added under ice-cooling. The mixture is stirred for 30 minutes, and added into a solution of phenol (2.4 g) and aluminum chloride (3.3 g) in methylene chloride (20 ml) with stirring under ice-cooling. The mixture is stirred for 1 hour under ice-cooling, and washed with water, saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution. The solution is dried over anhydrous sodium sulfate and concentrated in vacuo. A mixture of benzene and n-hexane (1:1) is added to the residue and the separated crystals are collected by filtration to give 6.4 g (90.2%) of the titled compound.

Provenance & Evidence