Carbamate → HCID 12085276, compound

Participants

Reaction Steps

To a solution of 186 mg of the above tert-butyl carbamate (0.55 mmol, 1 equiv.) in 1.6 mL anhydrous tert-butanol was added 52 μL of pyridine-3-carboxaldehyde (0.55 mmol, 1 equiv.) and 1.65 mL potassium tert-butoxide solution (1.0 M, 1.32 mmol, 3 equiv.). The mixture was heated to reflux overnight, then cooled. MeOH (5 mL) and HCl solution in dioxane (4.0 M) were added until pH 1, the reaction was then stirred for 1.5 h at ambient temperature. The mixture was then quenched with saturated NaHCO3 aqueous solution and extracted with EtOAc (2×50 mL). The aqueous layer was treated with 4 N NaOH aqueous solution until pH˜12 and extracted 2 more times. The combined organic extracts were washed with brine, dried (MgSO4), filtered and concentrated to afford a mixture of crude products, including naphthylamine still protected as the carbamate. The residue was therefore taken up in dichloromethane (3 mL), treated with 2 mL TFA and left stirring over a weekend at ambient temperature. The mixture was quenched and neutralized with saturated aqueous NaHCO3, extracted with dichloromethane (3×50 mL), dried (MgSO4) and filtered. The volatiles were removed in vacuo and the crude product purified by column chromatography on SiO2 using 50 to 100% EtOAc in hexane eluent mixtures giving 35 mg (0.11 mmol, 20% of theoretical yield) title compound.

Provenance & Evidence