A novel solid-stateMichaeladdition between pyrazolone 1 and 4-arylidenepyrazolones 2 at ambient temperature produced Michael adducts, 4,4′-arylidenebis(3-methyl-1-phenyl-5-pyrazolones) 3. Pyrazolones 3 formed salts 4 with Cu2+ in solution, indicating the enolic structure of the pyrazolone rings. The reactivity of 2 with 1 is discussed in terms of the electronic and steric effects of the substituent
The Michaeladdition reactions of indole to 4-arylidene-3-methyl-1-phenyl-5-pyrazolone 1 were investigated in the solid state, by which a series of new compounds, 1-aryl-1-(3-indolyl)-1-(3′-methyl-1′-phenyl-5′-pyrazolon-4′-yl)methanes 2, were easily obtained. This provides a feasible method of preparing novel compounds containing two heterocyclic groups at the same carbon.