Sulfuric Acid → Methyl 4-phenylpiperidine-4-carboxylate

Participants

Reaction Steps

To a stirred solution of H2SO4 (16 mL) in MeOH (400 mL), 4-phenyl-4-piperidinecarboxylic acid 4-methylbenzenesulfonate (37.7 g, 0.1 mole) was added and the mixture was stirred and refluxed for 8 hours. Excess methanol was evaporated at reduced pressure and the residue was poured into a mixture of ice and 6N NaOH. The pH was adjusted to 10-11 by adding more 6N NaOH and extracted with CH2Cl2 (3×150 mL). The combined CH2Cl2 extracts were dried (MgSO4) and the solvent evaporated to leave the desired product as a viscous oil. The 1H-NMR showed it to be pure (20.2 g, 92%) and was used without any further purification.

Provenance & Evidence