反应详情

A mixture of 2.2 g of sec-butyl 5-ethyl-2-methylnicotinate (10 mmol), 1.3 g of a-methylvalinamide (10 mmol) and 2.0 g of sulfur (62 mmol) in 2.5 g of chlorobenzene (114 wt%) is magnetically stirred at reflux temperatures for 24 hours. The reaction is cooled, diluted with methylene chloride, and filtered to remove unreacted sulfur. The filtrate is chromatographed on silica gel using 2:1 hexane-ethyl acetate as eluant to afford 2.5 g of the title product (72% yield) as a solid; recrystallization from ether-hexane gives mp 83°-87° C.

1. temperatureat reflux temperatures for 24 hours
2. temperatureThe reaction is cooled
3. filtrationfiltered
4. customto remove unreacted sulfur
5. customThe filtrate is chromatographed on silica gel using 2:1 hexane-ethyl acetate as eluant