反应详情

温度

5 °C

To a solution of 20 g of 1-[2-(4-pyridinylamino)benzoyl]piperidine (Example 1b) in 75 ml of sulfuric acid cooled in an ice-salt bath was slowly added a solution of 6.5 ml of concentrated nitric acid in 65 ml of sulfuric acid. The mixture was stirred at 5° C. for four hours and then poured onto ice and allowed to stand overnight. A crystalline acid-addition salt formed which was collected, dissolved in water and converted to the free base by adding sodium bicarbonate. The free base product was extracted with methylene dichloride, the extracts dried over anhydrous sodium sulfate and concentrated, and the residue triturated with ethyl acetate to give 9.3 g of 1-[5-nitro-2-(4-pyridinylamino)benzoyl]piperidine as a yellow powder, m.p. 194°-196° C.(decompn.).

1. additionpoured onto ice
2. waitto stand overnight
3. customA crystalline acid-addition salt formed which
4. customwas collected
5. dissolutiondissolved in water
6. additionby adding sodium bicarbonate
7. extractionThe free base product was extracted with methylene dichloride
8. dry with materialthe extracts dried over anhydrous sodium sulfate
9. concentrationconcentrated
10. customthe residue triturated with ethyl acetate