1-(Triphenylphosphoranylidene)acetone → 4-(2-Phenylpyrazolo[1,5-a]pyridin-3-yl)-3-buten-2-one

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Reaction Steps

A mixture of 2-phenylpyrazolo[1,5-a]-pyridine-3-carbaldehyde (0.50 g) and acetonylidenetriphenylphosphorane ##STR12## (0.82 g) in benzene (6 ml) was refluxed for 4 hours and then the solvent was evaporated in vacuo. The residue was chromatographed on silica gel (20 g) with chloroform as an eluent. The fractions containing the object compound were combined and evaporated in vacuo. The residue was recrystallized from ethanol to give crystals of 4-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)-3-buten-2-one (trans isomer) (0.21 g).

Provenance & Evidence