反应详情

Ethyl 3-bromo-2-oxopropanoate (24.7 mL) was added dropwise over 10 min to a solution of propanethioamide [Carboxylic Acid 1, step a] (15.8 g) in ethanol (150 mL) at 0-10° C. under nitrogen. When the addition was complete the mixture was stirred at ambient temperature for 18 hours. The mixture was concentrated in vacuo, the residue diluted with water and extracted into ethyl acetate (×3). The combined extracts were washed with brine, dried over magnesium sulfate, filtered and the solvent removed. The crude product was purified by flash silica chromatography, elution gradient 10, 15 and 20% ethyl acetate in isohexane. Fractions containing the product were evaporated to dryness to afford the subtitled compound as a pale green solid. Yield 16.0 g.

1. additionWhen the addition
2. concentrationThe mixture was concentrated in vacuo
3. additionthe residue diluted with water
4. extractionextracted into ethyl acetate (×3)
5. washThe combined extracts were washed with brine
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. customthe solvent removed
9. customThe crude product was purified by flash silica chromatography, elution gradient 10, 15 and 20% ethyl acetate in isohexane
10. additionFractions containing the product
11. customwere evaporated to dryness