Thiophene → Ethyl trans-3-hydroxy-4-[methyl(phenylmethyl)amino]-1-piperidinecarboxylate

Participants

Reaction Steps

(a-2) A mixture of 40 parts of ethyl trans-3-hydroxy-4-[(phenylmethyl)-amino]-1-piperidinecarboxylate, 15 parts of poly(oxymethylene), 2 parts of a solution of thiophene in methanol and 400 parts of methanol was hydrogenated at normal pressure and at room temperature with 4 parts of palladium-on-charcoal catalyst 10%. After the calculated amount of hydrogen was taken up, the catalyst was filtered off and the filtrate was evaporated. The residue was dissolved in trichloromethane. The organic layer was washed successively with a dilute ammonium hydroxide solution and water, dried, filtered and evaporated in vacuo. The residue was crystallized from 80 parts of acetonitrile The product was filtered off and dried, yielding 32.7 parts (79.9%) of ethyl trans-3-hydroxy-4-[methyl(phenylmethyl)amino]-1-piperidinecarboxylate (interm. 6).

Provenance & Evidence