Pyridine → 1-phenyl-3-(5-phenyl-benzofuran-2-ylmethoxycarbonylamino)-1H-pyrazole-4-carboxylic acid trimethylsilylethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-(trimethylsilyl)ethyl 3-amino-1-phenylpyrazol-4-carboxylate (967 mg, 3.1 mmol) in 11 ml dry toluene and pyridine (504 mg, 0.52 mL, 6.3 mmol) was added a phosgene solution (2.4 mL of a 1.93M toluene solution, 4.62 mmol) under nitrogen. A white precipitate formed immediately, and the mixture was heated at 90° C. for 30 min. The reaction mixture was cooled to room temperature, and filtered. The filtrate was taken to dryness. (5-Phenyl-benzofuran-2-yl)-methanol 1 (556 mg, 2.48 mmol) and DMAP (40 mg, 0.33 mmol) in 15 mL toluene were added to the residue under nitrogen. The reaction mixture was heated at 75° C. for 4 h, then concentrated to dryness. Purification by chromatography afforded 1.28 g of 1-phenyl-3-(5-phenyl-benzofuran-2-ylmethoxycarbonylamino)-1H-pyrazole-4-carboxylic acid trimethylsilylethyl ester, as a pale yellow solid.

Provenance & Evidence