Acetic Acid → 4-(N-(2-methyl-3-phenyl-2-(E)-propenyl)aminomethyl)-1-t-butoxycarbonylpiperidine

Participants

Reaction Steps

A mixture of 4-aminomethyl-1-t-butoxycarbonylpiperidine (3.6 g, 16.8 mmol), (E)-2-methyl-3-phenylpropenal (3.9 g, 26.7 mmol), acetic acid (3.9 g, 65 mmol), and 1,2-dichloroethane (30 mL) was stirred under argon at room temperature for 30 min before sodium triacetoxyborohydride (4.1 g, 19.3 mmol) was added. After 3 h saturated aqueous sodium bicarbonate was added to make the mixture basic, then it was diluted with water and extracted with dichloromethane (three times). The combined extracts were dried (anhydrous sodium sulfate) and evaporated under vacuum prior to column chromatography (silica gel, step-wise gradient of 2% to 4% of (10% concentrated aqueous ammonium hydroxide in methanol) in dichloromethane), which provided 4-(N-(2-methyl-3-phenyl-2-(E) -propenyl)aminomethyl)-1-t-butoxycarbonylpiperidine (3.72 g, 64% yield) as a pale yellow oil. A smaller excess of aldehyde over amine may produce optimal desired product yields when other aldehydes are used.

Provenance & Evidence