An Unconventional Method for Synthesis of 3-carboxyethyl-4-formyl(hydroxy)-5-aryl-N-arylpyrazoles.

An alternative highly regioselective synthetic method for the preparation of 3,5-disubstituted 4-formyl-N-arylpyrazoles in a one-pot procedure is reported. The methodology developed was based on the regiochemical control of the cyclocondensation reaction of beta-enamino diketones with arylhydrazines. Structural modifications in the beta-enamino diketone system allied to the Lewis acid carbonyl activator BF3 were strategically employed for this control. Also a one-pot method for the preparation of 3,5-disubstituted 4-hydroxymethyl-N-arylpyrazole derivatives from the beta-enamino diketone and arylhydrazine substrates is described.