Hydrochloric Acid → 4-Chloro-1-methyl-6-oxo-1,6-dihydropyridine-3-carboxylic acid

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Reaction Steps

4-Chloro-1-methyl-6-oxo-1,6-dihydro-pyridine-3-carboxylic acid ethyl ester (2.65 g, 12.3 mmol) was dissolved in a mixture of tetrahydrofuran (16 mL), acetonitrile (16 mL) and water (8 mL). Sodium hydroxide (1.23 g, 30.8 mmol) was added and the reaction mixture was allowed to stir at ambient temperature for 24 h. The reaction mixture was diluted with water (50 mL) and was acidified to pH 2 with 1 M hydrochloric acid and was extracted many times with ethyl acetate (about 1 L). The extracts were dried over anhydrous magnesium sulfate and concentrated in vacuo to afford an orange-tinged solid. Crystallization from methanol-ethyl acetate afforded 4-chloro-1-methyl-6-oxo-1,6-dihydro-pyridine-3-carboxylic acid (0.859 g, 37% yield) as an off-white solid: 1H NMR (DMSO-d6, 400 MHz) δ 13.02 (br s, 1H), 8.58 (s, 1H), 6.58 (s, 1H), 3.48 (s, 3H).

Provenance & Evidence