Hydrogen Bromide → 3-[4-[4-(4-Hydroxyphenyl)-1-piperazinyl]phenyl]-5,5-dimethyl-1-(1-methyl-2-oxopropyl)-2,4-imidazolidinedione

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Reaction Steps

A mixture of 25.6 parts of 3-[4-[4-(4-methoxyphenyl)-1-piperazinyl]phenyl]-5,5-dimethyl-1-(1-methyl-2-oxopropyl)-2,4-imidazolidinedione, 3 parts of sodium disulfite and 375 parts of a hydrobromic acid solution 48% in water was stirred for 6 hours at reflux temperature. After cooling. the crystallized product was filtered off, washed with 2-propanone and suspended in a mixture of water, trichloromethane and 1-butanol. The whole was treated with potassium carbonate (pH 8~9). The separated organic layer was set aside and the aqueous phase was extracted twice with the same mixture. The combined extracts (see above) were evaporated in vacuo. The residue was crystallized from 1-butanol. The product was filtered off and dried, yielding 21.3 parts (86%) of 3-[4-[4-(4-hydroxyphenyl)-1-piperazinyl]phenyl]-5,5-dimethyl-1-(1-methyl-2-oxopropyl)-2,4-imidazolidinedione; mp. 225.9° C. (intermediate 21).

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