Tautomeric Products of Condensation of Aromatic Aldehydes with Pyrazolone

Three products have been obtained by the condensation of aromatic aldehydes under different conditions with a 5-pyrazolone containing a reactive methylene group. The two bis-pyrazolone compounds are keto-enol tautomeric forms: one form shows carbonyl group absorption at 5.75 \(\mu\) in I.R. and the other form shows no peak between 5\(\mu\). and 6\(\mu\). p-Dimethylaminobenzaldehyde produces the same product under different condition