反应详情

Acetic acid (3.78 ml) was added to a stirred mixture of 2-thiophenecarbothioamide (3.15 g), ethyl chloroformylacetate potassium salt (6.23 g) and ethanol (60 ml). Afte refluxing for 4 h, ethyl chloroformylacetate potassium salt (4.15 g) and acetic acid (2.52 ml) were added, and then the refluxing was continued for further 20 h. The reaction mixture was concentrated, diluted with saturated aqueous sodium bicarbonate, and extracted with ethyl acetate. The ethyl acetate layer was washed with water, dried (MgSO4), and concentrated to give an oil which was purified by silica gel column chromatography. From the fraction eluted with ethyl acetate-hexane (1:1, v/v) the crystals of ethyl 2-(2-thienyl)-5-thiazolecarboxylate (3.29 g, 63%) were obtained. Recrystallization from ethyl acetate-hexane gave colorless needles, mp 61-62° C.

1. temperatureAfte refluxing for 4 h
2. concentrationThe reaction mixture was concentrated
3. additiondiluted with saturated aqueous sodium bicarbonate
4. extractionextracted with ethyl acetate
5. washThe ethyl acetate layer was washed with water
6. dry with materialdried (MgSO4)
7. concentrationconcentrated
8. customto give an oil which
9. customwas purified by silica gel column chromatography
10. washFrom the fraction eluted with ethyl acetate-hexane (1:1