FREMGANGSMAATE FOR N-DEMETHYLERING AV MORFINAN-ALKALOIDER

1. Process for the preparation of compounds having the N-demethylmorphinane structure of the general formula (III) see diagramm : EP0168686,P8,F1 wherein Z is CH2 -CH2 or CH=CH, Y is an oxygen atom or a group R3 and R4 wherein R3 is a hydrogen atom, a hydroxy group, an acyloxy group having from 1 to 3 carbon atoms or a benzoyloxy group, its spatial configuration being alpha, R4 is a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having from 1 to 3 carbon atoms, an acyloxy group having from 1 to 3 carbon atoms, a benzoyloxy or azido group, its spatial configuration being beta, R2 is hydrogen atom, an acyloxy group having from 1 to 3 carbon atoms or a benzoyloxy group, R1 is a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, an aryl or aralkyl group, an acyl group having from 1 to 3 carbon atoms or a benzoyl group, with the proviso that when R3 is a hydrogen atom, a hydroxy group, an acyloxy or benzoyloxy group, R4 is a hydrogen atom or an alkyl group, and when R4 is a hydrogen atom, a halogen atom, a hydroxy group, an acyloxy, benzoyloxy or azido group, R3 is a hydrogen atom, by reaction of morphinane alkaloids of the general formula (I) see diagramm : EP0168686,P9,F2 in which Z, Y, R1 and R2 have the definitions given above, with phosgene or diphosgene at a temperature of from 0 to 1208C in a solvent, and subsequent hydrolysis of the resulting N-chlorocarbonyl-N-demethyl derivative of the general formula (II) see diagramm : EP0168686,P9,F3 in which Z, Y, R1 and R2 have the meanings given above, with a mineral acid, which process is characterized in that the reaction with phosgene or diphosgene is carried out in 1,2-dichloroethane in the presence of alkali metal carbonates or alkali metal hydrogen carbonates, and then, without isolation, the resulting N-chlorocarbonyl-N-demethyl derivative of the general formula (II) is heated with 5 % hydrochloric acid.