Sodium Hydroxide → 7-(3'-Dimethylaminophenyl)-6-methyl-1,6-naphthyridine-5(6H)-one

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Reaction Conditions

Reaction Steps

The crude product of Example 7 (17.2 g.). was dissolved in ethanol and 4.3 g. of gaseous hydrogen chloride were bubbled in. The reaction mixture was heated for 5 minutes at 70° C. Two crops of a solid, 12.4 g., m.p. 197°-220° C. (dec.), and 1.9 g., m.p. 224°-226° (dec.), were obtained. The two crops were combined and recrystallized from ethanol to obtain 11.8 g., m.p. 221°-232° C. (dec.). The mother liquors from each of the crystallizations and recrystallizations were combined; two additional crops, 4.9 g. (total), m.p. 193°-216° C. (dec.), were obtained therefrom. 11.5 g. of the combined crystalline materials were dissolved in water, excess sodium hydroxide solution was added, and the basic solution was extracted with methylene chloride. The methylene chloride extract was dried over anhydrous sodium sulfate, filtered and evaporated at reduced pressure. The residue was chromatographed on silica gel using ethyl acetate as the eluant. The major fractions were combined and recrystallized from acetone/pentane, 7.6 g., m.p. 118°-120° C. An analytical sample had a melting point of 120° C. A second crop (2.4 g.), m.p. 117°-119° C., was also obtained.

Provenance & Evidence