反应详情

温度

0 °C

To a suspension of 2-amino-5-cyano-terephthalic acid dimethyl ester (11.6 g, 49.5 mmol) in hydrobromic acid (20 ml, 48%) at 0° C. was added an aqueous solution of sodium nitrite (55 mmol, 11 ml, 5M). The reaction mixture was stirred at 0° C. for 30 minutes. Copper (I) bromide (7.1 g, 49.5 mmol) was added as a solution in hydrobromic acid (10 ml, 48%) and the reaction mixture stirred at 0° C. for 10 min before heating at 65° C. for 1 hour. The reaction mixture was cooled to room temperature, diluted with water (50 ml) and the resultant mixture extracted with ethyl acetate (3×20 mL). The aqueous fraction was filtered to recover un-reacted 2-amino-5-cyano-terephthalic acid dimethyl ester (7.1 g). The combined organic fractions were washed with brine (20 ml), dried (MgSO4) and concentrated in vacuo. The resultant residue was subjected to flash chromatography (SiO2, gradient 0-50% ethyl acetate in cyclohexane) to yield the title compound as a brown solid (1.0 g, 7%). 1H NMR (CDCl3, 400 MHz) 8.43 (1H, s), 8.19 (1H, s), 4.04 (3H, s), 4.00 (3H, s).

1. stirringthe reaction mixture stirred at 0° C. for 10 min
2. temperaturebefore heating at 65° C. for 1 hour
3. temperatureThe reaction mixture was cooled to room temperature
4. extractionthe resultant mixture extracted with ethyl acetate (3×20 mL)
5. filtrationThe aqueous fraction was filtered
6. customto recover
7. customun-reacted 2-amino-5-cyano-terephthalic acid dimethyl ester (7.1 g)
8. washThe combined organic fractions were washed with brine (20 ml)
9. dry with materialdried (MgSO4)
10. concentrationconcentrated in vacuo