Methanol → Ethyl acetate methanol ammonium hydroxide

Participants

Reaction Steps

To 6-Methoxy-1,3,3-trimethyl-2-oxo-1,2,3,4-tetrahydro-quinoline-7-carbaldehyde (150 mg, 0.6 mmol) in 15 mL of toluene and 2 mL of MeOH was added triethylamine (134 mg, 1.32 mmol) and (2S,3S)-3-amino-2-phenylpiperidine dihydrochloride (150 mg, 0.60 mmol). After heating at reflux for 24 hours and concentrating, the residue was dissolved in CH2Cl2 and treated with sodium triacetoxyborohydride (200 mg). The reaction was stirred at room temperature overnight and quenched with satd NaHCO3. The aqueous portion was extracted with CH2Cl2, and the combined organic phases were washed with water and brine, dried over NaHCO3 and concentrated. Silica gel chromatography (90:9:1 EtOAc/MeOH/NH4OH) gave 52 mg (23%) of a colorless oil. Treatment with excess ethereal HCl and concentration gave 67 mg of the dihydrochloride salt as a white solid.

Provenance & Evidence