| abstract |
The invention relates to a process for the preparation of N-demethylmorphinan derivatives of the general formula (III) <IMAGE>, wherein morphinan alkaloids of the general formula (I) <IMAGE> with phosgene / diphosgene in halogenated hydrocarbons, aromatic hydrocarbons, ethers, Ketones as solvents in the presence of alkali carbonates / alkali hydrocarbonates are converted to N-chlorocarbonyl-N-demethyl derivatives of the general formula (II) <IMAGE>, then N-demethyl-morphinane derivatives are obtained by hydrolysis with aqueous / thin mineral acid in high purity with good yield. |