Abstract: The invention relates to a process for the preparation of morphinane derivatives of general formula: ##STR1## by demethylation of 3-methoxylated compound with a sulfonic acid selected from methanesulfonic acid and trifluoromethanesulfonic acid in the presence of a sulfide.

Abstract: The invention relates to a process for preparing .alpha.-hydroxy-alkanoic acids of general formula: ##STR1## in which R represents hydrogen or a lower alkyl radical and Cy represents phenyl or a heterocyclic radical, both radicals optionally comprising one or more substituents selected from the group consisting of lower alkyl, lower alkenyl, lower alkynyl radicals and halogen atoms, process which comprises the treatment of an .alpha.,.alpha.-dihalogenated ketone of general formula: ##STR2## in which R and Cy have the same meaning as above and X represents chlorine, bromine or iodine, in the presence of an aqueous solution of an alkali metal hydroxide and a non polar organic solvent selected from an aromatic or alicyclic hydrocarbon, the treatment being carried out at a temperature between the boiling temperature of the reaction medium at atmospheric pressure and 240.degree. C. under pressure and the alkali metal so formed is then acidified to obtain the desired acid.

Abstract: The invention relates to a process for preparing .alpha.-hydroxy-acids of general formula: ##STR1## in which R represents hydrogen or a lower alkyl radical and Cy represents a phenyl, naphthyl or heterocyclic radical, these latter three radicals optionally comprising one or more substituents selected from the group consisting of lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy radicals and halogen atoms, process which comprises the treatment of an .alpha.-monohalogenated ketone of general formula: ##STR2## in which R and Cy have the same meaning as above and X represents chlorine, bromine or iodine, in the presence of an aqueous solution of an alkali metal hydroxide, a non-polar organic solvent selected from an aromatic or alicyclic hydrocarbon and oxygen in excess optionally in the presence of an inert gas, the treatment being carried out at a temperature ranging from the boiling temperature of the reaction medium at atmospheric pressure and 240.degree. C.