1-Butanol → 6-fluoro-3-[4-(phenylmethyl)piperazinyl]-1H-indazole

Participants

Reaction Steps

A mixture of 40 parts of 1-[(2,4-difluorophenyl)thioxomethyl]-4-(phenylmethyl)piperazine, 144 parts of 1-butanol, 13 parts of hydrazine monohydrate and 24 parts of acetic acid was stirred overnight at reflux temperature. After cooling, 50 parts of sodium carbonate were added and stirring was continued for 3 hours at reflux temperature. The reaction mixture was cooled until room temperature and water and methylbenzene were added. After stirring for 15 minutes, the separated organic layer was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol (92:8 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from acetonitrile. The product was filtered off and dried, yielding 12 parts (32.2%) of 6-fluoro-3-[4-(phenylmethyl)piperazinyl]-1H-indazole; mp. 162.0° C. (int. 7).

Provenance & Evidence