反应详情

To a solution of 3-methylbutanethioamide (example 72, step b) (5.6 g) in ethanol (100 mL) was added ethyl 3-bromo-2-oxopropanoate (6.7 mL). The resulting mixture was stirred overnight at RT, then heated at reflux for 5 h. The solvent was evaporated and the residue was partitioned between ethyl acetate (250 mL) and saturated sodium hydrogen carbonate solution (100 mL). The layers were separated and the organic phase was washed with brine (100 mL), dried over magnesium sulphate, filtered and evaporated. The residue was purified by silica gel chromatography eluting with 20:1 to 10:1 isohexane:ethyl acetate gradient. The fractions containing product were combined and evaporated to give the subtitled compound as a yellow oil. Yield 5.2 g.

1. temperatureheated
2. temperatureat reflux for 5 h
3. customThe solvent was evaporated
4. customthe residue was partitioned between ethyl acetate (250 mL) and saturated sodium hydrogen carbonate solution (100 mL)
5. customThe layers were separated
6. washthe organic phase was washed with brine (100 mL)
7. dry with materialdried over magnesium sulphate
8. filtrationfiltered
9. customevaporated
10. customThe residue was purified by silica gel chromatography
11. washeluting with 20:1 to 10:1 isohexane
12. additionThe fractions containing product
13. customevaporated