Lithium hydroxide, monohydrate → HCID 76902673, compound

Participants

Reaction Steps

To a light brown solution of ethyl 7-bromo-4-oxo-1-(2-phenoxybenzyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylate (22) (230 mg, 0.5 mmol) in methanol (20 mL) was added the solid lithium hydroxide monohydrate (438 mg, 10.4 mmol) at room temperature. The resulting light brown solution was stirred for 15 h at room temperature at which time LCMS analysis indicated the absence of starting material. Then, it was diluted with water and the methanol was removed under vacuum. The resulting brown paste was difficult to dissolve in 1.0N NaOH and water. Then, the neutral impurities were extracted into ethyl acetate and the basic aqueous layer was diluted with water (˜100 mL). Then, the basic aqueous solution was neutralized with 1.0N HCl. The resulting solids were collected by filtration and washed with water and hexanes. After air drying, 40 mg of 7-bromo-4-oxo-1-(2-phenoxybenzyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylic acid (23) (17% yield) was isolated as an off-white solid.

Provenance & Evidence