反应详情

To a rb flask with an attached Dean-Stark trap containing molecular sieves, 4A (0.25 g) was added 4-bromothiazole-2-carbaldehyde (4.4 g, 22.91 mmol). The starting material was dissolved in Benzene (45 ml) and Ethylene glycol (1.406 ml, 25.2 mmol) was added followed by pTsOH (0.218 g, 1.146 mmol). The mixture was heated to reflux for 3 h. The mixture was cooled to rt, and was partitioned with sat. aq. NaHCO3. The mixture was washed 2× with sat. NaHCO3 (40 mL), then once with sat. NaCl (40 mL). The organic layer was dried with Na2SO4. The drying agent was removed by filtration, and the mixture was concentrated under reduced pressure. The residue was purified by biotage flash chromatography using a 40+M column and a 0 to 20% EtOAc in hexanes gradient. The product, 4-bromo-2-(1,3-dioxolan-2-yl)thiazole (5.1 g, 21.60 mmol, 94% yield), was collected as a light-yellow oil.

1. temperatureThe mixture was heated
2. temperatureto reflux for 3 h
3. customwas partitioned with sat. aq. NaHCO3
4. washThe mixture was washed 2× with sat. NaHCO3 (40 mL)
5. dry with materialThe organic layer was dried with Na2SO4
6. customThe drying agent was removed by filtration
7. concentrationthe mixture was concentrated under reduced pressure
8. customThe residue was purified by biotage flash chromatography