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AssigneeKabushiki Kaisha Cosmos Enterprise
InventorsBompei Yasui, Tomohisa Miyamoto, Katsuyuki Hiraoka, Yoshitaka Sako
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A process for the preparation of 1-(4-hydroxyphenyl)-2-(4-benzylpiperidino)-1-propanol (i.e. ifenprodil) and acid-addition salts thereof, characterized by brominating 4'-hydroxypropiophenone in a single or mixed solvent selected from the group consisting of methanol, ethanol and a saturated aliphatic ether, removing hydrogen bromide formed in the course of the bromination, adding 4-benzylpyridine to the reaction mixture, heating the reaction mixture under reflux in a single or mixed solvent selected from the group consisting of methanol and ethanol, and then subjecting the resultant reaction mixture to catalytic reduction to form 1-(4-hydroxyphenyl)-2-(4-benzylpiperidino)-1-propanol hydrobromide in the reaction mixture. The end product (i.e. ifenprodil) can be obtained according to this process in a high yield of about 80% within 14 hours from the starting material in a single reaction container throughout the process, without introducing a protective benzyl group into the starting material prior to the bromination.
A process for the preparation of 1-(4-hydroxyphenyl)-2-(4-benzylpiperidino)-1-propanol and acid-addition salts thereof in a single reaction container, which comprises brominating 4'-hydroxypropriophenone in a single or mixed solvent selected from the group consisting of methanol, ethanol and a saturated aliphatic ether, removing hydrogen bromide formed in the course of the bromination, adding 4-benzylpyridine and a single or mixed solvent selected from the group consisting of methanol and ethanol to the reaction mixture, heating the reaction mixture under reflux in a and then subjecting the resultant reaction mixture to catalytic reduction to form 1-(4-hydroxyphenyl)-2-(4-benzylpiperidino)-1-propanol hydrobromide in the reaction mixture.
A process for the preparation of 1-(4-hydroxyphenyl)-2-(4-benzylpiperidino)-1-propanol and acid-addition salts thereof in a single reaction container, which comprises brominating 4'-hydroxypropriophenone in a single or mixed solvent selected from the group consisting of methanol, ethanol and dioxane, removing hydrogen bromide formed in the course of the bromination, adding 4-benzylpyridine and a single or mixed solvent selected from the group consisting of methanol and ethanol to the reaction mixture, heating the obtained reaction mixture under reflux and then subjecting the resultant reaction mixture to catalytic reduction to form 1-(4-hydroxyphenyl)-2-(4-benzylpiperidino)-1-propanol hydrobromide.
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