Phosgene → 1-{1-[2-Hydroxy-3-(2-methoxy-phenyloxy)-propyl]-4-piperidyl}-3-phenyl-imidazolidin-2-one-hydrochloride

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Reaction Steps

With vigorous stirring, a solution of 117 ml of a 20% phosgene solution in toluene is added dropwise at a reaction temperature of 5° to 10° C. to an emulsion of 10 g of 1-[2-hydroxy-3-(2-methoxyphenyloxy)-propyl]-4-(2-anilino-ethylamino)-piperidine in 60 ml of toluene and 37.5 ml of a 3 N aqueous sodium hydroxide solution over 11/4 hours. Thereafter 35.5 ml of a 6 N aqueous potassium hydroxide solution are added dropwise at the same reaction temperature in the course of half an hour. Stirring is continued for 30 minutes at 5° to 10° C. and for 20 hours at room temperature. The reaction mixture is filtered with suction and the crystalline residue is treated with toluene. Recrystallisation from isopropanol yields 1-{1-[2-hydroxy-3-(2-methoxy-phenyloxy)-propyl]-4-piperidyl}-3-phenyl-imidazolidin-2-one-hydrochloride in the form of white crystals with a melting point of 185°-187° C. The salt can be converted into the free compound for example by treatment with an aqueous sodium hydroxide solution.

Provenance & Evidence