反应详情

1 g of β-carbolin-3-carboxylic acid ethyl ester is slowly introduced at room temperature into 20 ml of concentrated nitric acid (65%). After addition is complete, the solution is heated to 70°-75° C., whereupon a clear solution forms. After about 30 minutes, the solution becomes turbid. After a total stirring time of 1.5 hours at 70°-75° C., the solution is allowed to cool and the sediment is poured onto 100 g of ice. After filtering with suction, recrystallization from pyridine is carried out. 6-nitro-β-carbolin-3-carboxylic acid ethyl ester of melting point 320°-325° C. is isolated in 55% yield.

1. additionAfter addition
2. temperaturethe solution is heated to 70°-75° C., whereupon a clear solution forms
3. customAfter a total stirring time of 1.5 hours
4. customat 70°-75° C.
5. temperatureto cool
6. filtrationAfter filtering with suction, recrystallization from pyridine