To a stirred solution of (2-{5-[6-(methyloxy)-1,5-naphthyridin-4-yl]-2-pyridinyl}ethyl)amine hydrochloride salt (0.69 mmole) in dry CH2Cl2 (25 mL) and dry EtOH (10 mL) at RT was added triethylamine (0.29 mL, 2.07 mmole) and 2,3-dihydro[1,4]dioxino[2,3-c]pyridine-7-carbaldehyde (0.12 g, 0.73 mmole). After 24 h, the reaction contents were concentrated and dried under high vacuum. To a stirred solution of the crude imine in dry EtOH (25 mL) at RT was added NaBH4 (0.03 g, 0.73 mmole). After 24 h, Silica gel (5 g) was added to the reaction solution and the suspension was concentrated under vacuum to a dry solid. Purification on silica (CHCl3/MeOH, 9:1 containing 5% NH4OH) afforded the title compound (0.50 g, 72%) as light yellow solid: 1H NMR (400 MHz, CD3OD) δ 9.52 (d, J=1.8 Hz, 1H), 9.22 (d, J=5.6 Hz, 1H), 9.02 (d, J=8.3 Hz; 1H), 8.57 (m, 2H), 8.48 (d, J=5.6 Hz, 1H), 8.19 (d, J=9.3 Hz, 1H), 7.79 (s, 1H), 7.68 (d, J=9.3 Hz, 1H), 4.66 (m, 4H), 4.54 (s, 2H), 4.13 (s, 3H), 3.82 (m, 2H), 3.71 (s, 2H). LC-MS (ES) m/e 430 (M+H)+.
