Acetaldehyde → 4-{[Ethyl-(7-nitro-1,2,3,4-tetrahydro-naphthalen-2-yl)-amino]-methyl)-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of 4-[(7-nitro-1,2,3,4-tetrahydro-naphthalen-2-ylamino)-methyl]-piperidine-1-carboxylic acid tert-butyl ester (485 mg, 1.25 mmol) and acetaldehyde (110 μL, 1.49 mmol) in dichloroethane (20 mL) under a nitrogen atmosphere was added sodium triacetoxyborohydride (530 mg, 2.49 mmol, 2 eq.) in a single portion. The reaction was stirred at room temperature for 24 h then concentrated in vacuo. The residue was partitioned between EtOAc (75 mL) and 5% aq. KOH (50 mL). The aqueous phase was extracted twice more with EtOAc (2×30 mL). The combined organic layers were dried over MgSO4, filtered, and concentrated onto silica (10 g). This was placed on top of a flash column and eluted with 20% acetone in hexanes. The fractions containing product were pooled and concentrated to afford 4-{[ethyl-(7-nitro-1,2,3,4-tetrahydro-naphthalen-2-yl)-amino]-methyl}-piperidine-1-carboxylic acid tert-butyl ester as a yellow oil (430 mg).

Provenance & Evidence