反应详情

Sodium ethylate (71 g, 1.05 mol) was added under vigorous stirring to a solution of 4-methylthiopene-2-carbaldehyde (88 g, 80% purity, 0.56 mol) and diethyl succinate (183 g, 1.05 mol) in ethanol (1 L). The reaction mixture was refluxed for 3 h and evaporated in vacuum (˜20 mmHg) at 50° C. until the solvent distillation ceased. The obtained residue was diluted with 500 mL of 10% HCl and 500 mL of ethyl acetate. The mixture was shaken. The organic layer was separated, diluted with 1 L of a saturated aqueous solution of NaHCO3, and shaken. The aqueous layer was separated, neutralized by 10% HCl to pH 2, and subjected to extraction by 1 L of ethyl acetate. The organic layer was evaporated in vacuum (˜20 mmHg) at 60° C. and chromatographed on a layer of silica gel (300×150 mm) with hexane/ethyl acetate mixture, 1:1 as eluent. Fractions with the target product were collected and evaporated in vacuum to give the desired product 61 g (0.24 mol, 43%) as yellow crystals.

1. temperatureThe reaction mixture was refluxed for 3 h
2. customevaporated in vacuum (˜20 mmHg) at 50° C. until the solvent distillation
3. additionThe obtained residue was diluted with 500 mL of 10% HCl and 500 mL of ethyl acetate
4. customThe organic layer was separated
5. additiondiluted with 1 L of a saturated aqueous solution of NaHCO3
6. stirringshaken
7. customThe aqueous layer was separated
8. extractionsubjected to extraction by 1 L of ethyl acetate
9. customThe organic layer was evaporated in vacuum (˜20 mmHg) at 60° C.
10. customchromatographed on a layer of silica gel (300×150 mm) with hexane/ethyl acetate mixture, 1:1 as eluent
11. customFractions with the target product were collected
12. customevaporated in vacuum