tert-Butyl 3-broMo-7,8-dihydro-1,6-naphthyridine-6(5H)-carboxylate

625100-00-7

24424-99-5

1184950-48-8

Step 1: To a dry flask was added 3-bromo-5,6,7,8-tetrahydro-1,6-naphthyridine (1.50 g, 7.04 mmol) followed by THF (70 mL, 863 mmol), di-tert-butyl dicarbonate (1.77 g, 8.10 mmol), triethylamine (TEA, 5.89 mL, 42.2 mmol), and 4-dimethylaminopyridine (DMAP, 43.0 mg, 0.352 mmol). The reaction mixture was stirred at room temperature for 4 hours. After completion of the reaction, the solvent was removed by concentration under reduced pressure. The residue was extracted by adding ethyl acetate (EtOAc, 150 mL) and water (50 mL) to the residue. After separation of the organic layer, the aqueous layer was further extracted with ethyl acetate (2 x 150 mL). All organic layers were combined and washed sequentially with water (2 × 100 mL) and brine (100 mL), then dried with anhydrous magnesium sulfate (MgSO4). After filtration, the organic layer was concentrated under reduced pressure to afford the target product tert-butyl 3-bromo-7,8-dihydro-1,6-diazanaphthalene-6(5H)-carboxylate (2.15 g, 97.5% yield). The product was confirmed by LC-MS(FA)ES+ m/z 314; 1H NMR (methanol-d4, 300 MHz) δ 8.43 (s, 1H), 7.83 (s, 1H), 4.60 (s, 2H), 3.73 (t, J=6.0 Hz, 2H), 2.89 (t, J=6.0 Hz, 2H), 1.48 (s, 9H).