Diisopropylethylamine → 2-(pivaloyloxymethyl)-4-isopropyl-6-methoxy-1,2-benzisothiazol-3(2H)-one 1,1-dioxide

Participants

Reaction Steps

To a suspension of 4-isopropyl-6-methoxy-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (1.020 kg, 4.2 mol) in 6 L of acetonitrile was added diisopropylethylamine (543 g, 4.2 mol) and the reaction mixture was stirred at ambient temperature for 30 minutes. At the end of this period, chloromethyl pivalate (633 g, 4.2 mol) was added in one portion and the resulting solution was refluxed on a steam bath for 20 hours. The acetonitrile was removed under vacuum and the residue was stirred with 6 L of water for 30 minutes. The off-white solid was collected by filtration, washed first with 6 L of water, followed by 3 L of hexane. The product was dried at 70° C. under vaccum for 18 hours to give 1.33 kg (91%) of 2-(pivaloyloxymethyl)-4-isopropyl-6-methoxy-1,2-benzisothiazol-3(2H)-one 1,1-dioxide, m.p. 178°-179° C.

Provenance & Evidence