p-Toluenesulfonic acid monohydrate → 7-Bromo-2-tert-butyl-5-methyl-6-styryl-1,3-benzoxazole-4-carbonitrile

Participants

Reaction Steps

Toluene (3 ml), p-toluenesulfonic acid monohydrate (1.4 mg, 7.5 μmol) were added to N-(3-bromo-6-cyano-2-hydroxy-5-methyl-4-styrylphenyl)-2,2-dimethylpropionamide (I-14) (31 mg, 75 μmol), followed by refluxing with a Dean-Stark condenser for 2.5 hours. After cooling, saturated sodium bicarbonate water (30 ml) was added to the reaction liquid, the product was extracted with ethyl acetate (30 ml×2). The organic layer was washed with saturated brine (30 ml), dried over anhydrous magnesium sulfate, concentrated under reduced pressure, the residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=8:1) to obtain the entitled compound (25 mg, 84%) as a colorless solid.

Provenance & Evidence