Ethyl chloroformate → 3-(3-Methylpyridazin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine

Participants

Reaction Steps

To a mixture of 2-phenylpyrazolo[1,5-a]pyridine (5.00 g), 3-methylpyridazine (2.90 g) and methylene chloride (20 ml), was added a solution of ethyl chloroformate (5.57 g) in methylene chloride for 17 minutes under ice-cooling and stirred for an hour at the same temperature and then for 6 hours and 40 minutes at room temperature. To the reaction mixture was added methylene chloride (20 ml), and washed with a solution of potassium carbonate (10 ml) and a saturated aqueous solution of sodium chloride (10 ml) and dried over magnesium sulfate. The solvent was removed and chromatographed on silica gel (70 g) with a mixture of n-hexane and ethyl acetate (2:1). The fractions containing the object compound were combined and evaporated in vacuo and recrystallized from a mixture of ethyl acetate and n-hexane to give 3-(3-methylpyridazin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine (2.36 g).

Provenance & Evidence