Hydrogen Bromide → 3-[(4-Fluorophenyl)(4-piperidinylidene)methyl]pyridine

Participants

Reaction Steps

A mixture of 100 parts of ethyl 4-[(4-fluorophenyl)(3-pyridinyl)methylene]-1-piperidinecarboxylate and 375 parts of a hydrobromic acid solution 48% was stirred and refluxed for 3 hours. The reaction mixture was evaporated. The residue was washed with 2,2'-oxybispropane. The latter was decanted, the residue was stirred in water and the whole was alkalized with a sodium hydroxide solution. The product was extracted with trichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column-chromatography (2×) over silica gel using a mixture of trichloromethane and methanol, saturated with ammonia, (80:20 by volume) as eluent. The main fraction was collected and the eluent was evaporated, yielding 30 parts (37%) of 3-[(4-fluorophenyl)(4-piperidinylidene)methyl]pyridine as a residue (intermediate 21).

Provenance & Evidence