反应详情

A solution of 2-cyano-benzimidic acid ethyl ester hydrochloride (43 g, 0.20 mol) and 2,2-diethoxy-ethylamine (30 ml, 0.21 mol) in methanol (430 ml) was aged at room temperature for 1 h. The reaction mixture was concentrated to remove methanol and conc. sulfuric acid (110 ml) was added. After heating on a steam bath for 1.5 h, the reaction mixture was diluted with water (700 ml) and extracted with chloroform. The aqueous phase was made strongly basic with sodium hydroxide and extracted with chloroform. hydrochloric acid (12N) was added to give pH 3–4, tar was filtered and the filtrate was concentrated. The resultant brown solid was sublimed at 200–220° C. The purified solid was dissolved in hydrochloric acid solution (6N, 110 ml), byproducts filtered and the filtrate concentrated. The residue was diluted with ethanol (100–120 ml) containing hydrochloric acid (12N, 1 ml), boiled briefly and filtered. Further concentration and cooling of the filtrate gave 2-(1H-imidazol-2-yl)benzonitrile hydrochloride (1.5 g). The filtrate was concentrated further and diluted with acetone. Filtration gave 2-(1H-imidazol-2-yl)-benzoic acid hydrochloride (7.3 g). Dilution of the filtrate with acetone and filtration of the resultant solid gave additional 2-(1H-imidazol-2-yl)-benzonitrile hydrochloride; mp 200–204° C.; IR 4.5 μ.

1. concentrationThe reaction mixture was concentrated
2. customto remove methanol and conc. sulfuric acid (110 ml)
3. additionwas added
4. temperatureAfter heating on a steam bath for 1.5 h
5. additionthe reaction mixture was diluted with water (700 ml)
6. extractionextracted with chloroform
7. extractionextracted with chloroform
8. additionhydrochloric acid (12N) was added
9. customto give pH 3–4, tar
10. filtrationwas filtered
11. concentrationthe filtrate was concentrated
12. customwas sublimed at 200–220° C
13. dissolutionThe purified solid was dissolved in hydrochloric acid solution (6N, 110 ml)
14. filtrationbyproducts filtered
15. concentrationthe filtrate concentrated
16. additionThe residue was diluted with ethanol (100–120 ml)
17. additioncontaining hydrochloric acid (12N, 1 ml)
18. filtrationfiltered
19. concentrationFurther concentration
20. temperaturecooling of the filtrate