Reaktion #497564

Reaktionsgleichung

Thiazole

isopropylmagnesium chloride lithium chloride

ethyl difluoroacetate

→

2,2-difluoro-1-(1,3-thiazol-2-yl)ethanone

Ausbeute 92.0%

Lösungsmittel

ethyl acetate

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThen the solution was cooled to −20° C.
2. 2
   workup.STIRRINGThe mixture was stirred for 10 minutes at −20° C.
3. 3
   Sonstige10 minutes
4. 4
   Sonstigeat room temperature
5. 5
   Waschenwashed with aqueous ammonium chloride (saturated, 200 mL)
6. 6
   Trocknendried (MgSO4)
7. 7
   Filtrationfiltered
8. 8
   Sonstigethe solvent was evaporated under reduced pressure
9. 9
   SonstigeThe residue was purified by column chromatography on silica gel (chromatography on silica gel, 0-90% ethyl acetate in hexanes)

Vorschrift

This procedure is based on literature, see: Krasovskiy, A.; Krasovskaya, V.; Knochel, P. Angew. Chem. Int. Ed. 2006, 45, 2958. Thiazole (5.7 mL, 80 mmol) in THF (100 mL) was added to a stirred, cooled (0° C.) solution of isopropylmagnesium chloride-lithium chloride (1.18 M in THF, 74.9 mL, 88 mmol) in THF (75 mL) then the mixture was stirred at room temperature for 1 hour. Then the solution was cooled to −20° C. and ethyl difluoroacetate (9.29 ml, 88 mmol) was added. The mixture was stirred for 10 minutes at −20° C., then 10 minutes at room temperature. The mixture was diluted with ethyl acetate (200 mL), washed with aqueous ammonium chloride (saturated, 200 mL), dried (MgSO4), filtered and the solvent was evaporated under reduced pressure. The residue was purified by column chromatography on silica gel (chromatography on silica gel, 0-90% ethyl acetate in hexanes) to give 2,2-difluoro-1-(1,3-thiazol-2-yl)ethanone (12 g, 73.6 mmol, 92% yield) as a yellow oil. MS ESI: [M+H]+ m/z 164.0.

Quelle