反应详情

A reaction vessel was charged with 4.17 g (0.03 mol) of para-nitrophenol, 50 ml of dry dimethylformamide containing dimethylamine as impurity, and potassium carbonate. After stirring of this mixture at ambient temperature, there was added 4.86 g (0.02 mol) of ethyl 2-chloro-4-trifluoromethyl-5-oxazolecarboxylate. The reaction mixture was stirred at ambient temperature for 24 hours. The resulting yellow mixture was extracted with ethyl ether and water. The organic phase was washed five times successively with 5% sodium hydroxide and five times with water, then dried with magnesium sulfate, and concentrated under reduced pressure to yield 2.2 g of a yellow solid which was recrystallized in methylcyclohexane to yield 1.7 g of a white powder. Chromatographic separation on silica gel using dichloroethane as eluent yielded 0.96 g of a light yellow powder product (m.p.=53°-55° C.) identified in Table I.

1. stirringThe reaction mixture was stirred at ambient temperature for 24 hours
2. extractionThe resulting yellow mixture was extracted with ethyl ether and water
3. washThe organic phase was washed five times successively with 5% sodium hydroxide and five times with water
4. dry with materialdried with magnesium sulfate
5. concentrationconcentrated under reduced pressure