反应详情

A suspension 4-amino-2-ethoxybenzoic acid (20 g, 110 mmol) in 2N hydrochloric acid (200 mL) was well stirred with ice bath cooling. To this was added sodium nitrite (7.68 g, 111 mmol) in 22 mL of water. After stirring for 5 min, solid sodium carbonate was added to adjust the pH to 9-10. Separately, copper chloride (14.2 g, 143 mmol) in 200 mL water was slowly added to a solution of sodium cyanide ((18.28 g, 371 mmol) in 200 mL water at 0-5° C. and stirred for 2 h. The cold nitrite solution was added slowly to the cyanide solution and stirred at 0-5° C. for 15 min, followed by 25° C. for 2 h. This was filtered and the aqueous solution was adjusted to pH 2 with concentrated hydrochloric acid. This was extracted with ethyl acetate (4 L). The organic extracts were washed with brine and dried over anhydrous magnesium sulfate. The solids were filtered off, and the filtrate was concentrated to give 19 g of crude 4-cyano-2-ethoxybenzoic acid.

1. temperaturecooling
2. stirringstirred for 2 h
3. stirringstirred at 0-5° C. for 15 min
4. waitfollowed by 25° C. for 2 h
5. filtrationThis was filtered
6. extractionThis was extracted with ethyl acetate (4 L)
7. washThe organic extracts were washed with brine
8. dry with materialdried over anhydrous magnesium sulfate
9. filtrationThe solids were filtered off
10. concentrationthe filtrate was concentrated