Triphenylphosphine → 7-[(2,3-Difluorobenzyl)oxy]-2,5-dimethylpyrazolo[1,5-a]pyridine-3-carboxylic Acid ethyl Ester

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Reaction Steps

A solution of 180 mg (0.768 mmol) of 7-hydroxy-2,5-dimethylpyrazolo[1,5-a]pyridine-3-carboxylic acid ethyl ester from Example 8A in 7 ml of dry tetrahydrofuran was admixed with 221.5 mg (1.537 mmol) of (2,3-difluorophenyl)methanol (CAS 75853-18-8), 423.2 mg (1.614 mmol) of triphenylphosphine and 0.32 ml (1.614 mmol) of diethyl azodicarboxylate. The resulting mixture was stirred at room temperature for 1 h, some of the solvent was drawn off under reduced pressure and the residue was admixed with 5 ml of tert-butyl methyl ether. The resulting precipitate was filtered off and dried under reduced pressure, which gave 190 mg (67% of theory, 97% pure) of the target compound.

Provenance & Evidence