Hydrochloric Acid → HCID 21073767, compound

7-{4-[4-(7-Methoxy-5,8-dihydro-naphthalen-1-yl)-piperazin-1-yl]-butoxy}-1H-[1,8]naphthyridin-2-one (360 mg, 0.78 mmol) was dissolved in a mixture of ethanol (6 mL) and tetrahydrofuran (2 mL). To this was added 10% hydrochloric acid (1.5 mL) and the mixture was stirred at room temperature for 15 minutes, then quenched with saturated sodium bicarbonate (10 mL). The mixture was extracted with ethyl acetate (20 mL) and the organic layer was washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and evaporated. The crude solid was purified by column chromatography (6:94 triethylamine/ethyl acetate) to yield the title compound (263 mg, 75%) as a white foam. 1H NMR (400 MHz, CDCl3) δ 9.15 (s, 1H), 7.76 (d, 1H), 7.60 (d, 1H), 7.20 (t, 1H), 7.00–6.95 (m, 2H), 6.60 (d, 1H), 6.50 (d, 1H), 4.40 (t, 2H), 3.60 (s, 2H), 3.04 (t, 2H), 2.90–2.80 (m, 4H), 2.80–2.40 (m, 8H), 1.90–1.60 (m, 4H), MS ES+ 447.05 (M+H)+ (Exact mass: 446.23).