Reaction #45557

Reaction equation

Toluene

p-toluenesulfonic acid monohydrate

N-(2-bromo-5-cyano-3,3′-dihydroxy-6-methylbiphenyl-4-yl)-2,2-dimethylpropionamide

→

compound

Yield 95.0%

7-Bromo-2-tert-butyl-6-(3-hydroxyphenyl)-5-methyl-1,3-benzoxazole-4-carbonitrile

Yield 95.0%

Solvents

water

Conditions

Workup

1. 1
   Temperatureby refluxing with a Dean-Stark condenser for 3 hours
2. 2
   TemperatureAfter cooling
3. 3
   Extractionthe product was extracted with ethyl acetate (50 ml×2)
4. 4
   WashThe organic layer was washed with saturated brine (50 ml)
5. 5
   Dryingdried over anhydrous magnesium sulfate
6. 6
   Concentrationconcentrated under reduced pressure
7. 7
   Otherthe residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=3:1)

Procedure

Toluene (45 ml), p-toluenesulfonic acid monohydrate (21.0 mg, 111 μmol) were added to N-(2-bromo-5-cyano-3,3′-dihydroxy-6-methylbiphenyl-4-yl)-2,2-dimethylpropionamide (I-16) (446 mg, 1.11 mmol), followed by refluxing with a Dean-Stark condenser for 3 hours. After cooling, water (50 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=3:1) to obtain the entitled compound (404 mg, 95%) as a colorless solid.

Source