反应详情

A solution of 1.7 g of hydroxylamine, O-sulfonic acid in 6 ml of water is added to a solution of 1.83 g of 3,4-dihydroxy-5-nitrobenzaldehyde in 25 ml of water, subsequently stirred at 65° for 3.5 hours, cooled, the separated precipitate is filtered off under suction and taken up in ethyl acetate. The organic phase is dried over sodium sulfate and evaporated in a water-jet vacuum. The crystals obtained are recrystallized from ethyl acetate/n-hexane. There is obtained 3,4-dihydroxy-5-nitrobenzonitrile in the form of yellow crystals of m.p. 194°-195°.

1. temperaturecooled
2. filtrationthe separated precipitate is filtered off under suction
3. dry with materialThe organic phase is dried over sodium sulfate
4. customevaporated in a water-jet vacuum
5. customThe crystals obtained
6. customare recrystallized from ethyl acetate/n-hexane