Ethyl 2-hydroxyisobutyrate → Ethyl 2-fluoroisobutyrate

Temperature

-70 °C

Ethyl 2-hydroxyisobutyrate (12.43 g) was stirred in dry methylene chloride (65 ml) at -70° C. under nitrogen. Diethylaminosulphur trifluoride (30.32 g) in dry methylene chloride (5 ml) was added slowly, maintaining the temperature at -70° C. After completion of the addition, the mixture was stirred at -70° C. for 1 hour and was then allowed to warm to room temperature, stood for 3 hours and then overnight. The reaction was then carefully added to ice with vigorous stirring, and the resultant methylene chloride layer combined with a further methylene chloride extract of the aqueous layer. The total organic fraction was washed with brine, dried over magnesium sulphate and the solvent carefully distilled, to leave ethyl 2-fluoro-isobutyrate as a bronze liquid (12.8 g); 1H NMR analysis indicated that this material was >95% pure, and contained 2-3% of ethyl methacrylate. NMR (CDCl3, 270 MHz) δ 1.31(3H,t), 1.58(6H,d), 4.25(2H,q) ppm; 1H NMR (CDCl3, 254 MHz, 19F) δ -148.0 (1F, septet) ppm.

1. additionAfter completion of the addition
2. temperatureto warm to room temperature
3. waitstood for 3 hours
4. customovernight
5. additionThe reaction was then carefully added to ice with vigorous stirring
6. extractionextract of the aqueous layer
7. washThe total organic fraction was washed with brine
8. dry with materialdried over magnesium sulphate
9. distillationthe solvent carefully distilled

ORD record

ord-6c851f8cd07446e08062180c114a0b64

Source dataset

uspto-grants-1998_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05750778