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

Beteiligte Stoffe

Reaktionsschritte

Toluene (25 ml), p-toluenesulfonic acid monohydrate (10.9 mg, 57.2 μmol) were added to N-(3-bromo-6-cyano-2-hydroxy-4-iodo-5-methylphenyl)-2,2-dimethylpropionamide (I-7) (250 mg, 572 μmol), followed by refluxing with a Dean-Stark condenser for 3 hours. After cooling, saturated sodium bicarbonate water (30 ml) was added to the reaction liquid, the product was extracted with ethyl acetate (50 ml×2). The organic layer was washed with saturated brine (50 ml), dried over anhydrous magnesium sulfate, concentrated under reduced pressure, the residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=6:1) to obtain the entitled compound (225 mg, 94%) as a pale yellow solid.

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