1-Benzyl-4-methyl-4-phenylpiperidine → 4-Methyl-4-phenylpiperidine

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Reaction Steps

Freshly prepared methanolic formic acid solution (4.4% by weight, 70 mL) was added to 1-benzyl-4-methyl-4-phenylpiperidine (3.23 g, 12.2 mmol, 1.00 equiv). To the resulting solution was added palladium on carbon (10% Pd, 2.00 g). The mixture was stirred at room temperature for 24 hours. The solid was filtered out and washed with MeOH (30 mL), H2O (15 mL), CH2Cl2 (30 mL) and MeOH (15 mL). The combined filtrate and washings were concentrated, and the residue was dissolved in CH2Cl2 (50 mL) and H2O (10 mL). The aqueous phase was adjusted to pH 11 by addition of 1N aqueous NaOH. The organic phase was separated, dried over MgSO4 and concentrated. The residual oil was purified by flash chromatography (SiO2, CHCl3—MeOH—NH3 (2.0M in MeOH) 100:4:0 to 100:20:10) to afford 1.20 g of 1-benzyl-4-methyl-4-phenylpiperidine and 1.10 g (51%, 82% based on unrecovered starting material) of 4-methyl-4-phenylpiperidine, which was characterized spectroscopically.

Provenance & Evidence