Hydrogenation process for the preparation of piperidyl-(4)-ethers

The invention comprises piperidyl-4-ethers of the general formula: in which R is an alkyl radical containing at least 2 carbon atoms. These compounds and the methyl ether are prepared by hydrogenating the corresponding pyridyl-4-ethers in the presence of a ruthenium catalyst, at an increased pressure and elevated temperature. Alternatively, the pyridyl-4-ether may be used as its N-oxide. The catalyst may be ruthenium metal, an oxide or a salt of ruthenium, or a ruthenate. The hydrogenation may be performed in the presence of small amounts of water and/or an alcohol, preferably corresponding to the alkoxy group in the ether. Compounds prepared include those in which R is methyl, ethyl, n-propyl and isopropyl.