反应详情

N-tert-butoxycarbonyl-thiourea (0.600 g, 3.40 mmole) was suspended in ethanol (5 mL) and the mixture was cooled in an ice-water bath. To this mixture was added a solution of bromo-thioacetic acid S-ethyl ester (0.880 g [75% pure]; 3.61 mmole) in ethanol (5 mL). Following completion of the addition, the mixture was warmed to room temperature and stirred overnight. After 20 hours, the reaction was concentrated. The residue was partitioned between methylene chloride and water. The organic phase was washed with water and brine. The aqueous phases were then backwashed with methylene chloride. The two organic phases were combined, dried over sodium sulfate and concentrated. The crude material was purified by chromatography over silica gel eluted with 20% v/v ethyl acetate in hexanes, to give (4-ethylsulfanyl-thiazol-2yl)-carbamic acid tert-butyl ester (0.514 g, 58%).

1. temperaturethe mixture was cooled in an ice-water bath
2. additioncompletion of the addition
3. waitAfter 20 hours
4. concentrationthe reaction was concentrated
5. customThe residue was partitioned between methylene chloride and water
6. washThe organic phase was washed with water and brine
7. dry with materialdried over sodium sulfate
8. concentrationconcentrated
9. customThe crude material was purified by chromatography over silica gel
10. washeluted with 20% v/v ethyl acetate in hexanes