反应详情

温度

83 °C

A 2-L four-necked flask equipped with a mechanical stirrer, thermometer, addition funnel, reflux condenser, and nitrogen inlet was charged with absolute ethanol (250 mL) and an ethanolic solution of sodium ethoxide (21%, 190 mL, 0.504 mol). The mixture was heated to reflux at about 83° C. It was then treated with 3-chloro-2(1H)-pyridinone hydrazone (68.0 g, 0.474 mol). The mixture was re-heated to reflux over a period of 5 minutes. The yellow slurry was then treated dropwise with diethyl maleate (88.0 mL, 0.544 mol) over a period of 5 minutes. The reflux rate increased markedly during the addition. By the end of the addition all of the starting material had dissolved. The resulting orange-red solution was held at reflux for 10 minutes. After being cooled to 65° C. the reaction mixture was treated with glacial acetic acid (50.0 mL, 0.873 mol). A precipitate formed. The mixture was diluted with water (650 mL), causing the precipitate to dissolve. The orange solution was cooled in an ice bath. Product began to precipitate at 28° C. The slurry was held at about 2° C. for 2 hours. The product was isolated via filtration, washed with aqueous ethanol (40%, 3×50 mL), and then air-dried on the filter for about 1 hour. The title product compound was obtained as a highly crystalline, light orange powder (70.3 g, 55% yield). No significant impurities were observed by 1H NMR.

1. customA 2-L four-necked flask equipped with a mechanical stirrer
2. additionthermometer, addition funnel
3. temperaturereflux condenser, and nitrogen inlet
4. temperatureThe mixture was heated
5. temperatureThe mixture was re-heated
6. temperatureto reflux over a period of 5 minutes
7. temperatureThe reflux rate increased markedly during the addition
8. additionBy the end of the addition all of the starting material
9. dissolutionhad dissolved
10. temperatureat reflux for 10 minutes
11. temperatureAfter being cooled to 65° C. the reaction mixture
12. customA precipitate formed
13. dissolutionto dissolve
14. temperatureThe orange solution was cooled in an ice bath
15. customto precipitate at 28° C
16. customThe product was isolated via filtration
17. washwashed with aqueous ethanol (40%, 3×50 mL)
18. customair-dried on the
19. filtrationfilter for about 1 hour