Hydrochloric Acid → 1-(2-bromo-4-chlorophenyl)-2-(1H-1,2,4-triazol-1-yl)ethanone

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Reaction Steps

A mixture of 456 parts of 1-[[2-(2-bromo-4-chlorophenyl)-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole and 1584 parts of concentrate hydrochloric acid was stirred and refluxed for 4 hours. The whole was treated with a sodium hydroxide solution 50%. After stirring for a while, the precipitated product I was filtered off, washed with water and set aside. The filtrate was extracted first twice with 4-methyl-2-pentanone and then three times with trichloromethane. The 4-methyl-2-pentanone layers were dried, filtered and evaporated. The residue was stirred in 2-propanol. The precipitated product II was filtered off and set aside. The trichloromethane-layers were dried, filtered and evaporated. The residue was stirred in 2-propanol. The precipitated product was filtered off and purified, together with product I and product II which were set aside, by column chromatography over silica gel using a mixture of dichloromethane, ethanol and ammonium hydroxide (98.5:1:0.5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from 2,2' -oxybispropane and 2-propanol. The product was filtered off and dried, yielding 17 parts of 1-(2-bromo-4-chlorophenyl)-2-(1H-1,2,4-triazol-1-yl)ethanone (62).

Provenance & Evidence