Sodium Bicarbonate → 5-ethyl 6-tert-butyl 2-methoxy-7,8-dihydro-1,6-naphthyridine-5,6(5H)-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

Trimethyloxonium tetrafluoroborate (1.775 g, 12.00 mmol) was added to a mixture of 5-ethyl 6-tert-butyl 2-hydroxy-7,8-dihydro-1,6-naphthyridine-5,6(5H)-dicarboxylate (1.289 g, 4.00 mmol) and acetonitrile (18 mL) at 0° C. The mixture was stirred at 0° C. for 2 hr, and the reaction mixture was poured into ice-cooled saturated aqueous sodium hydrogencarbonate solution (100 mL), and the mixture was extracted with ethyl acetate (×3). The organic layer was washed with water and brine, and dried over magnesium sulfate, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography (solvent gradient; 2→19% ethyl acetate/hexane) to give 5-ethyl 6-tert-butyl 2-methoxy-7,8-dihydro-1,6-naphthyridine-5,6(5H)-dicarboxylate (372 mg, 1.106 mmol, 28%) as a colorless oil.

Provenance & Evidence