Halothane → 1,1,1-Trifluoro-2-bromo-2-chloro-5-methyl-4-hexen-3-ol

Tetrahydrofuran (230 ml) and sodium t-butoxide (57.6 g; 40% w/v solution in dimethylformamide) was charged to a split-neck reaction flask, and cooled to -60° C. with stirring. 1-Bromo-1-chloro-2,2,2-trifluorethane (47.6 g) and senecialdehyde (20.9 g) were charged simultaneously over 25 minutes, then the mixture was stirred at -60° C. for a further 30 minutes. On completion of reaction, the mass was quenched by controlled addition of saturated ammonium chloride solution (120 ml). Hexane (500 ml) was added to the mixture, then the aqueous phase was separated and extracted with further hexane (2×500 ml). The combined organics were washed with brine (2×100 ml) and then water (3×20 ml). Drying (sodium sulphate) and concentration in vacuo then gave the product 5-bromo-5-chloro-4-hydroxy-2-methyl-6,6,6-trifluorohex-2-ene as a mobile yellow oil (50.1 g, 70% yield).

1. stirringthe mixture was stirred at -60° C. for a further 30 minutes
2. customOn completion of reaction
3. customthe mass was quenched by controlled addition of saturated ammonium chloride solution (120 ml)
4. additionHexane (500 ml) was added to the mixture
5. customthe aqueous phase was separated
6. extractionextracted with further hexane (2×500 ml)
7. washThe combined organics were washed with brine (2×100 ml)
8. customDrying
9. concentration(sodium sulphate) and concentration in vacuo

ORD record

ord-c5c150db0d6042c384ac6e15e60907af

Source dataset

uspto-grants-1998_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05731475