2-phenyl-4H-pyrazol-3-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a mixture of 2,4-dihydro-2-phenyl-3H-pyrazol-3-one (378 mg; 2.36 mmol) in DMF (6 ml) was added under nitrogen at room temperature 249 mg (4.3 mmol) of KF with stirring followed by 2-bromomethyl-4-isopropyl-6-methoxy-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (750 mg, 2.15 mmol). The resulting mixture was stirred at room temperature for 2 hours and then quenched with saturated ammonium chloride solution. The above mixture was extracted with ether (3×30 ml) and the organic layer was dried over magnesium sulfate, and concentrated in vacuo. The residue (yellow solid) was purified by flash chromatography (silica gel; 5% ethyl acetate in methylene chloride) to afford 280 mg (31%) of 4-isopropyl-6-methoxy-2-(1-phenylpyrazol-5-yl-oxymethyl)-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (Formula I: R1 =Ph; R2 =R3 =H; R4 =CH(CH3)2 ; R5 '6-OCH3) as a white solid, m.p. 118°-1190° C. The resulting mixture was stirred at room temperature for 2 hours quenched with saturated ammonium chloride solution The above mixture was extracted with ether (3×30 ml) the organic layer was dried over magnesium sulfate concentrated in vacuo The residue (yellow solid) was purified by flash chromatography (silica gel; 5% ethyl acetate in methylene chloride)