Dimethyl Sulfoxide → 2,4-dihydro-4-[4-[4-(4-methoxyphenyl)-1-piperazinyl]phenyl]-2-(1-methylethyl)-3H-1,2,4-triazol-3-one

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Reaction Steps

A mixture of 10 parts of 2,4-dihydro-4-[4-[4-(4-methoxyphenyl)-1-piperazinyl]phenyl]-3H-1,2,4-triazol-3-one, prepared as described in Example XVII of U.S. Pat. No. 4,267,179, 1.5 parts of a sodium hydride dispersion 50% and 300 parts of dimethyl sulfoxide was stirred at 60° C. under nitrogen atmosphere till foaming had ceased. Then there were added 5.24 parts of 2-bromopropane and stirring was continued for 1 hour at 60° C. Another 1.5 parts of a sodium hydride dispersion 50% was added and stirring was continued till foaming had ceased. Then another 5.24 parts of 2-bromopropane was aded and the whole was stirred for 1 hour at 60° C. The reaction mixture was cooled and poured into water. The product was extracted with trichloromethane. The extract was washed with water, dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol (99:1 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from 1-butanol, yielding 5.2 parts (47%) of 2,4-dihydro-4-[4-[4-(4-methoxyphenyl)-1-piperazinyl]phenyl]- 2-(1-methylethyl)-3H-1,2,4-triazol-3-one; mp. 209.5° C. (intermediate 9).

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