Sodium hydride → 1-Amino-3-(4-chloro-2-fluoro-5-isopropyloxyphenyl)-6-trifluoromethyl-1,2,3,4-tetrahydropyrimidine-2,4-dione

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Reaction Steps

A suspension of sodium hydride (10 g, 60% in oil) in N,N-dimethylformamide (30 ml) was stirred at 0° C. under nitrogen while a solution of ethyl 3-amino-4,4,4-trifluorocrotonate (4.5 g) in N,N-dimethylformamide (20 ml) was added dropwise. After stirring for 15 minutes, a solution of 4-chloro-2-fluoro-5-isopropyloxyphenylisocyanate (5.6 g) in toluene (25 ml) was added slowly at -35° C. The solution was stirred at room temperature for 2 hours and treated with a solution of 2,4-dinitrophenoxyamine (5.8 g) in N,N-dimethylformamide (20 ml). Stirring was continued for 3 days. The solution was processed and gave a solid which was chromatographed on silica gel eluting with ethyl acetate:hexane, 1:5, containing 0.1% of triethylamine. 1-Amino-3-(4-chloro-2-fluoro-5-isopropyloxyphenyl)-6-trifluoromethyl-1,2,3,4-tetrahydropyrimidine-2,4-dione was obtained as a white solid (5.3 g).

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