反应详情

To 450 ml concentrated sulfuric acid cooled to 10° is added 50.0 g (0.2 m) 3-amino-5,6-dichloropyrazine carboxylic acid. To this solution cooled to 0°-5°, is added a cold solution of 15 ml fuming sulfuric acid in 15 ml fuming nitric acid dropwise over 15 minutes. The reaction mixture is stirred at 0°-5° for 2 hours and then at ambient temperature for 2 hours. The reaction mixture is then poured onto ice and the yellow solid is collected. This solid is taken up in ethyl acetate, washed twice with saturated sodium carbonate solution and then the solution is filtered through a pad of silica gel. The resulting solution is evaporated in vacuo to afford 35 g of 5,6-dichloro-3-nitropyrazinamine, m.p. 169°-170° C.

1. temperatureTo this solution cooled to 0°-5°
2. additionis added a cold solution of 15 ml
3. customdropwise over 15 minutes
4. waitat ambient temperature for 2 hours
5. additionThe reaction mixture is then poured onto ice
6. customthe yellow solid is collected
7. washwashed twice with saturated sodium carbonate solution
8. filtrationthe solution is filtered through a pad of silica gel
9. customThe resulting solution is evaporated in vacuo