Sodium hydride → 3-[3-(6-Methoxy-m-tolyl)-1,2-benzisothiazol-5-yl)-6-(trifluoromethyl)-2,4(1H,3H)-pyrimidinedione

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Reaction Conditions

Reaction Steps

A mixture of 60% sodium hydride in mineral oil (15.9 g, 0.397 mol) and N,N-dimethylformamide is cooled to -10° C., treated over one hour with a solution of ethyl 3-amino-4,4,4-trifluorocrotonate (72.7 g, 0.397 mol) in ether, warmed to and stirred at room temperature for 90 minutes, cooled to -70° C., treated over 80 minutes with a solution of 3-(6-methoxy-m-tolyl)-1,2-benzisothiazol-5-yl isocyanate (107 g, 0.361 mol) in N,N-dimethylformamide while maintaining the temperature below about -65° C., slowly warmed to and stirred at room temperature overnight, and poured onto ice. The resultant aqueous mixture is washed with ethyl acetate, acidified to pH 2 with concentrated hydrochloric acid, and extracted with diethyl ether. The organic extract is dried over anhydrous magnesium sulfate and concentrated in vacuo to give the title product as an orange oil (110 g, 70.5%) which is identified by NMR spectral analyses.

Provenance & Evidence