1-(6-Chloro-3-pyridazinyl)-5-(2-pyridyl)pyrazole-3-carboxylic acid ethyl ester → methyl 1-(6-methoxy-3-pyridazinyl)-5-(2-pyridyl)-1H-pyrazole-3-carboxylate

Participants

Reaction Steps

28% Sodium methoxide-methanol (3 mL) was added to the above-obtained 1-(6-chloro-3-pyridazinyl)-5-(2-pyridyl)pyrazole-3-carboxylic acid ethyl ester (1.50 g) in methanol (45 mL), and the resultant mixture was refluxed under heat for 2 hours, and then cooled in air. The reaction solvent was removed under reduced pressure, and the residue was partitioned by use of ethyl acetate and saturated aqueous sodium hydrogencarbonate. The organic layer was dried over magnesium sulfate anhydrate, followed by filtration. The solvent was removed under reduced pressure, and the residue was purified through silica gel chromatography (ethyl acetate-hexane), to thereby give 1-(6-methoxy-3-pyridazinyl)-5-(2-pyridyl)pyrazole-3-carboxylic acid methyl ester as a solid (480 mg, 34%).

Provenance & Evidence