反应详情

温度

0 °C

3-Bromo-5-trifluoromethyl-phenylamine (4.0 mL, 28.3 mmoles) was dissolved into concentrated HCl (70 mL). This solution was chilled to 0° C. and to it was slowly added a solution of sodium nitrite (2.5 g, 36.2 mmoles) in 50 mL of water. After completion of the addition enough ethanol (90%) was added (25 mL) to affect nearly complete dissolution of the resultant mixture. The mixture was stirred at 0° C. for an additional 20 minutes. After this period the heterogeneous mixture was quickly transferred (cold) to an addition funnel. The diazonium mixture was added to a solution of O-ethylxanthic acid, potassium salt (5.7 g, 35.6 mmoles) in 50 mL of water at 60° C. The mixture was next heated to 90° C. and was stirred at this temperature for 2 hours. After this period the mixture was allowed to cool to ambient temperature, and the crude xanthate (a red liquid) was removed from the bottom of the aqueous mixture via pipette. The crude product taken up in 100 mL of diethyl ether and was washed with water (2×25 mL) and brine (20 mL). The ether layer was evaporated in vacuo to yield crude xanthate. The crude product was purified using flash silica chromatography (0-1% EtOAc/Hexane) to yield 4.7 g (51% yield) of dithiocarbonic acid S-(3-bromo-5-trifluoromethyl-phenyl) ester O-ethyl ester as a red liquid. 1H-NMR (CDCl3): δ 7.83 (d, J=5.8 Hz, 2H), 7.71 (s, 1H), 4.63 (q, J=7.1 Hz, 2H), 1.36 (t, J=7.1 Hz, 3H).

1. waitAfter this period the heterogeneous mixture was quickly transferred
2. temperatureThe mixture was next heated to 90° C.
3. stirringwas stirred at this temperature for 2 hours
4. waitAfter this period the mixture was allowed
5. temperatureto cool to ambient temperature
6. customthe crude xanthate (a red liquid) was removed from the bottom of the aqueous mixture via pipette
7. washwas washed with water (2×25 mL) and brine (20 mL)
8. customThe ether layer was evaporated in vacuo
9. customto yield crude xanthate
10. customThe crude product was purified