Hydrochloric Acid → 4-Amino-6-(4-chloro-2-fluoro-3-methoxyphenyl)-3-ethynyl-pyridine-2-carboxylic acid methyl ester

Participants

Reaction Steps

4-Acetylamino-6-(4-chloro-2-fluoro-3-methoxyphenyl)-3-trimethylsilanylethynylpyridine-2-carboxylic acid methyl ester (0.196 g, 0.437 mmol) was suspended in methanol (4.36 mL) and acetyl chloride (0.310 mL, 4.37 mmol) was added. The reaction mixture was stirred overnight at ambient temperature then concentrated to dryness. The residue was dissolved in methanol (4.36 mL) and potassium carbonate (0.121 g, 0.873 mmol) was added. The reaction mixture was stirred at ambient temperature for 2 h, acidified with 2N HCl, and concentrated but not to dryness. The residue was partitioned between ethyl acetate and sodium bicarbonate; and the organic phase was dried and concentrated. The resulting product was purified by flash chromatography on silica gel (ethyl acetate/hexane gradient) to yield the title compound (0.109 g, 74.6% yield) as a yellow solid, mp 167-169° C.: 1H NMR (CDCl3) δ 7.7 (m, 1H), 7.24 (s, 1H), 7.18 (m, 1H), 5.08 (br s, 2H), 3.99 (s, 3H), 3.97 (d, 3H), 3.84 (s, 1H).

Provenance & Evidence