反应详情

温度

25 °C

10 g (63.7 mmol) of 2-trimethylsilylthiazole (1) and 435 ml of toluene are placed in a 2-liter round-bottomed flask under argon. The reaction mixture is stirred and cooled using an ice bath, and, when the temperature has reached about 8° C., a solution of 12.2 ml (0.128 mol) of ethyl chloroformate in 500 ml of toluene is added. Once all the solution has been added, the mixture is left for about 10 minutes and then warmed to 25° C. After stirring for 20 hours, 200 ml of aqueous sodium carbonate solution are added and the mixture is stirred for 30 minutes. After separation of the phases by settling, the organic phase is washed with 200 ml of saturated aqueous sodium chloride solution. After drying over magnesium sulfate, the organic phase is concentrated to dryness under reduced pressure. The residue is purified by flash chromatography (msilica=200 g; eluent: 60/40 cyclohexane/ethyl acetate). 5.12 g of ethyl 2-thiazolecarboxylate (2) are thus obtained in the form of a greenish liquid that crystallizes. Rf(50/50 cyclohexane/ethyl acetate)=0.52.

1. temperaturecooled
2. customhas reached about 8° C.
3. additionOnce all the solution has been added
4. stirringAfter stirring for 20 hours
5. stirringthe mixture is stirred for 30 minutes
6. customAfter separation of the phases
7. washthe organic phase is washed with 200 ml of saturated aqueous sodium chloride solution
8. dry with materialAfter drying over magnesium sulfate
9. concentrationthe organic phase is concentrated to dryness under reduced pressure
10. customThe residue is purified by flash chromatography (msilica=200 g; eluent: 60/40 cyclohexane/ethyl acetate)