反应详情

To a stirred, cooled solution of 40 ml. of concentrated sulfuric acid (at 0°-5° C.) was added, dropwise, 4.0 g. (0.015 mole) of 1-ethyl-2-methyl-5-methylsulfonyl-6-chlorobenzimidazole. Stirring was continued until all solid was in solution. To this stirred and cooled solution was added 6.0 g. (0.086 mole) of 90% fuming nitric acid, dropwise, over a 30 minute period. Stirring was continued while cooling for 9 hours and then the reaction mixture allowed to warm to room temperature over a 14 hour period. An additional 13.5 g. of 30% fuming sulfuric acid was then added, dropwise. The reaction mixture was stirred for about 24 hours and then stirred at about 40° C. for an additional 64 hours. The resultant reaction mixture was poured into a stirred mixture of 300 ml. of ice +200 ml. of concentrated ammonium hydroxide. The resultant aqueous mixture was extracted thrice with 100 ml. portions of chloroform and the combined chloroform extracts dried over anhydrous sodium sulfate. The resultant chloroform solution was evaporated to dryness under reduced pressure to give 3.04 g. (73.4%) of the desired product, melting at 75°-79° C.

1. temperatureTo a stirred, cooled solution of 40 ml
2. stirringTo this stirred
3. temperaturecooled solution
4. additionwas added 6.0 g
5. stirringStirring
6. temperaturewhile cooling for 9 hours
7. stirringThe reaction mixture was stirred for about 24 hours
8. stirringstirred at about 40° C. for an additional 64 hours
9. customThe resultant reaction mixture
10. additionwas poured into a stirred mixture of 300 ml
11. extractionThe resultant aqueous mixture was extracted thrice with 100 ml
12. dry with materialportions of chloroform and the combined chloroform extracts dried over anhydrous sodium sulfate
13. customThe resultant chloroform solution was evaporated to dryness under reduced pressure
14. customto give 3.04 g