反应详情

温度

40 °C

Concentrated H2SO4 (440 mL) was added slowly to crushed ice (1200 g) and 2-amino-3-chloro-5-nitrobenzonitrile (43.8 g) was suspended in the resulting H2SO4 solution. After addition of 2-propanol (1600 mL), the mixture was heated to 40° C. internal temperature with vigorous stirring. A solution of NaNO2 (66.0 g) in water (100 mL) was added dropwise. After completion of addition, the mixture was kept at 40° C. for an additional 3 h, then cooled to ambient temperature and extracted with CH2Cl2. The organic extract was washed sequentially with water, 0.1 N NaOH, water, and brine, and then dried over MgSO4, filtered through a pad of silica gel, and evaporated to yield the crude product as a yellow solid. Chromatography on silica gel (20% EtOAc/hexanes) followed by crystallization from 2-propanol yielded the product as yellow crystals. 1H-NMR (CDCl3): δ 8.47 (1H, t, J=2.0 Hz), 8.43 (1H, dd, J=1.4, 2.0 Hz), 7.98 (1H, dd, J=1.4, 2.0 Hz). 13C-NMR (CDCl3): δ 148.8, 137.4, 137.0, 128.1, 125.3, 115.4, 115.3.

1. additionAfter completion of addition
2. temperaturecooled to ambient temperature
3. extractionextracted with CH2Cl2
4. extractionThe organic extract
5. washwas washed sequentially with water, 0.1 N NaOH, water, and brine
6. dry with materialdried over MgSO4
7. filtrationfiltered through a pad of silica gel
8. customevaporated
9. customto yield the crude product as a yellow solid
10. customChromatography on silica gel (20% EtOAc/hexanes) followed by crystallization from 2-propanol