Hydrochloric Acid → 5-(4-Methoxy-phenyl)-7-methyl-5,6,7,8-tetrahydro-[1,7]naphthyridin-2-ol hydrochloride

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Reaction Steps

5-(4-Methoxy-phenyl)-7-methyl-5,6,7,8-tetrahydro-[1,7]naphthyridin-2-ol. A solution of 2-methoxy-5-(4-methoxy-phenyl)-7-methyl-5,6,7,8-tetrahydro-[1,7]naphthyridine (1.75 g, 6.15 mmol) in 4 M HCl (100 mL) was heated at reflux for 5 h. The solution was concentrated to give 5-(4-methoxy-phenyl)-7-methyl-5,6,7,8-tetrahydro-[1,7]naphthyridin-2-ol hydrochloride. The salt was neutralized with satd. aq. NaHCO3, and extracted with DCM. The organic layer was concentrated to give the title compound (1.14 g, 68%) as the free base. MS (ESI): mass calcd. for C16H18N2O2, 270.33; m/z found, 271.4 [M+H]+. 1H NMR (CDCl3): 7.12-7.07 (m, 2H), 7.03 (d, J=9.3, 1H), 6.87-6.82 (m, 2H), 6.37 (d, J=9.3, 1H), 4.00-4.92 (m, 1H), 3.80 (s, 3H), 3.69-3.62 (m, 1H), 3.56-3.50 (m, 1H), 3.01-2.95 (m, 1H), 2.52-2.45 (m, 1H), 2.44 (s, 3H).

Provenance & Evidence