Hydrochloric Acid → 4-(4-Fluorobenzoyl)pyridine

Participants

Reaction Steps

To a stirred and cooled (ice-bath) solution of 141.5 parts of 4-pyridinecarbonyl chloride hydrochloride in 400 parts of fluorobenzene were added portionwise 399 parts of aluminum chloride. Upon completion, the whole was slowly heated to reflux and stirring at reflux was continued for 6 hours. The reaction mixture is cooled, poured onto crushed ice and acidified with 240 parts of a hydrochloric acid solution 10N. The layers were separated. The acid aqueous phase was washed twice with 180 parts of methylbenzene and strongly alkalized with a sodium hydroxide solution 60%. The product was extracted three times with dichloromethane. The combined extracts were dried, filtered and evaporated. The residue was dissolved in 900 parts of methylbenzene and the solution was treated with activated charcoal. The latter was filtered off and the filtrate was evaporated. The residue was crystallized from 2,2'-oxybispropane, yielding 152 parts (75.5%) of (4-fluorophenyl)(4-pyridinyl)methanone; mp. 85.5° C. (intermediate 25).

Provenance & Evidence