Dimethylformamide → 5-Bromo-1,1,1-trifluoro-2-pentanone

Participants

Reaction Conditions

Reaction Steps

A 500 mL three neck round bottom flask, fitted with dropping funnel, magnetic stirrer, ice-salt bath, and argon inlet is charged with 125 mL of dry dimethylformamide, 29 g(35.7 mM) of trifluoro-5-hydroxy-2-pentanone. This mixture was cooled to -5° C. and 11.5 g(71.6 mM) of bromine was added dropwise over a two hour period. After stirring overnight at ambient temperature the reaction mixture was distilled through a 30 cm vigreaux column at 2.0 mm of pressure. Two fractions were collected; the first fraction from 27°-35° C. and the second fraction at 35°-70° C. The second fraction was partitioned between water and ethyl ether, the organic layer was washed with water (3×100 mL, dried (anhydrous MgSO4), and evaporated under reduced pressure at ambient temperature to give 40 g of a colorless oil mixture of dimethyl formamide, ether, and the desired product which was used in the next reaction without further purification.

Provenance & Evidence