Hydrochloric Acid → 2-[(4-Fluorophenyl)methyl]thiophene

Participants

Reaction Conditions

Reaction Steps

33.8 g of aluminium trichloride were suspended in 217 g of chlorobenzene, and a solution of 40.3 g of 4-fluorobenzoyl chloride in 37.4 g of chlorobenzene was added dropwise to this at 0° C. over the course of 15 minutes. The mixture was then stirred for 1 hour and then, at 0° C., 21.8 g of thiophene were added dropwise over the course of 20 minutes. The resulting hydrogen chloride was drawn off and absorbed in sodium hydroxide solution. The mixture was subsequently heated to 80° C. and the remaining hydrogen chloride was removed. The resulting solution was added dropwise to a suspension of 7.2 g of sodium borohydride in 47.2 g of digylme while stirring at 70° C. over the course of 45 minutes. The reaction mixture was then stirred for 90 minutes and then cooled to room temperature and discharged into a mixture of 250 g of ice, 44.6 g of concentrated aqueous hydrochloric acid and 500 g of water. The organic phase which formed thereby was separated off, the aqueous phase was extracted by shaking with chlorobenzene, and the combined organic phases were distilled. 35.0 g of product with a boiling point of 83° C./1.0 mbar and a purity of 99.7% (GC) were obtained. This corresponds to 73.9% of theory. The product contained less than 0.1% by weight of defluorinated compounds (GC).

Provenance & Evidence