Acetaldehyde → 2-Ethyl-2-azabicyclo[3.3.1]nonane

To a solution (2 ml) of 2-azabicyclo[3.3.1]nonane (100 mg, 0.62 mmol) in methanol were added a 10% acetaldehyde solution (5 ml) and 10% palladium on activated carbon (100 mg) and the mixture was stirred for 3 hours under the hydrogen atmosphere. The reaction mixture was filtered by means of suction, and the filtrate was concentrated under a reduced pressure. A saturated aqueous solution of sodium bicarbonate (10 ml) was added to the residue, followed by extraction with chloroform (3×20 ml). The extrant was dried (over MgSO4), followed by removal of the solvent and purification of the residue with silica gel column chromatography (chloroform-methanol-triethylamine=100:9:1), to obtain 2-ethyl-2-azabicyclo[3.3.1]nonane (68 mg, 72%) as a colorless oily material.