Boron tribromide → 2-bromomethyl-4-isopropyl-6-hydroxy-1,2-benzisothiazol-3(2H)-one 1,1-dioxide

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Reaction Steps

A mixture of 2-bromomethyl-4-isopropyl-6-methoxy-l,-2-benzisothiazol-3(2H)-one 1,1-dioxide (44 g, 126.4 mmol) and BBr3 (1.0M in methylene chloride, 164.4 mmol) was allowed to reflux for 48 hours and then poured into ice/water. The mixture was filtered, the aqueous layer was extracted with ethyl acetate, and the mixture of the combined organic layer and the residue (from above filtration) was dried over sodium sulfate and concentrated in vacuo. The solid residue was recrystallized from toluene/cyclohexane (7:2) to afford 52.6 g (96 %) of 2-bromomethyl-4-isopropyl-6-hydroxy-1,2-benzisothiazol-3 (2H)-one 1,1-dioxide as solid, m.p. 167°-169° C.

Provenance & Evidence