Water → 4-isopropyl-6-methoxy-2-(1,3-diphenylpyrazol-5-yl-oxymethyl)-1,2-benzisothiazol-3(2H)-one 1,1-dioxide

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Reaction Conditions

Reaction Steps

A mixture 2,4-dihydro-2,5-diphenyl-3H-pyrazol-3-one (Formula III: R1 =R2 =Ph; R3 =H) (651 mg; 2.76 mmol) and Cs2CO3 (450 mg; 1.38 mmol) in methanol (12 ml) was stirred at 20° C. for 5 hours. The solvent was concentrated in vacuo, and the residue was dried in vacuo overnight. To a solution of the above residue in 12 ml of DMF was added 2-bromomethyl-4-isopropyl-6-methoxy-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (800 mg, 2.3 mmol) and the resulting mixture was stirred at room temperature (20° C.) for 21 hours and then poured into water. The above mixture was extracted with ether (3×) and the organic layer was dried over sodium sulfate, and concentrated in vacuo. The residue (yellow foam, 854 mg, 74%) was purified by flash column chromatography (silica gel; 18-50% ethyl acetate in hexane) and by recrystallization from ethyl acetate/hexane to afford 609 mg of 4-isopropyl-6-methoxy-2-(1,3-diphenylpyrazol-5-yl-oxymethyl)-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (Formula I: R1 =R2 =Ph; R3 =H; R4 =CH(CH3)2 ; R5 =6-OCH3) as a white foam, m.p. 62°-76° C.

Provenance & Evidence