Potassium Carbonate → 5-{[3-(4-fluoro-phenyl)-5-methyl-isoxazol-4-ylmethyl]-amino}-2-methyl-2H-pyrazole-3-carboxylic acid methyl ester

Participants

Reaction Steps

To a solution of 3-(4-fluoro-phenyl)-5-methyl-isoxazole-4-carbaldehyde (1.32 g, 6.44 mmol) and the 5-amino-2-methyl-2H-pyrazole-3-carboxylic acid methyl ester hydrochloride (1.0 g, 6.44 mmol) in methanol (30 mL) at room temperature was added potassium carbonate (890 mg, 6.44 mmol) and then the reaction mixture was heated under reflux for 2 h. After cooling to room temperature sodium borohydride (487 mg, 12.9 mmol) was added and then the mixture heated under reflux for 12 h. The mixture was then cooled and treated with hydrochloric acid (1 N, 10 drops) and evaporated. Water was then added and the mixture extracted with ethyl acetate. The aqueous layer was acidified with hydrochloric acid (2 N) and then extracted with ethyl acetate. The combined organic extracts were then dried over sodium sulfate, filtered and evaporated to afford 5-{[3-(4-fluoro-phenyl)-5-methyl-isoxazol-4-ylmethyl]-amino}-2-methyl-2H-pyrazole-3-carboxylic acid methyl ester (27%) which was obtained as a white solid.

Provenance & Evidence