Pyridine → HCID 22728884, compound

Participants

Reaction Steps

To a solution of 4-biphenylboronic acid (1.0 g, 5.1 mmol) and ethyl 3-methylpyrazole-5-carboxylate (0.78 g, 5.1 mmol) in 25 mL dry DCM were added pyridine (1.2 mL, 15 mmol) and anhydrous powder of copper(II) acetate (1.84 g, 10 mmol). Some activated molecular sieve powder was added afterwards. The resulting slurry was refluxed for 2 days under argon. The mixture was diluted with DCM, filtered through celite. The blue filtrate was washed with water (×2), dried, concentrated, purified with flush column to yield ethyl 3-methyl-1-(4-phenylphenyl)-1H-pyrazole-5-carboxylate (26%), Rf 0.67 (1:2 EtOAc:hexane), ES-MS: (M+H)+ 307; and its regioisomer, ethyl 5-methyl-1-(4-phenylphenyl)-1H-pyrazole-3-carboxylate (31%), Rf 0.50 (1:2 EtOAc:hexane), ES-MS: (M+H)+ 307.

Provenance & Evidence