Dimethylformamide → 2-(6-Methoxy-[1,5]naphthyridin-4-yl)4,5,6,7-tetrahydro-2H-indazol-5-ylamine

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Reaction Steps

8-Bromo-2-methoxy-[1,5]naphthyridine. To a suspension of 6-methoxy-[1,5]naphthyridin-4-ol (8.8 g, 0.050 mol) in DMF (167 mL) was added PBr3 (4.7 mL, 0.050 mol) at 45° C. The suspension became homogeneous and then a suspension formed over 20 min. The mixture was cooled to RT and the solid was filtered and washed with Et2O (100 mL). Further solids precipitated from the filtrate and were collected. Water (50 mL) was added to the solid and the suspension was basified with 1 N NaOH (200 mL). The aqueous layer was extracted with CH2Cl2 (3×250 mL), washed with brine (150 mL), dried (MgSO4) and concentrated. The resulting residue was purified on SiO2 (0-60% EtOAc/hexanes) to provide 8.9 g (75%) of the title compound as a white solid. MS (ESI): exact mass calculated for C9H7BrN2O, 237.97; m/z found, 239.2 [M+H]+. 1H NMR (400 MHz, DMSO-d6): 8.57 (d, J=4.7, 1H), 8.27 (d, J=9.0, 1H), 8.05 (d, J=4.7, 1H), 7.30 (d, J=9.0, 1H), 4.04 (s, 3H).

Provenance & Evidence