posted on 2015-05-01, 00:00authored byAhmed Kamal, K. N. Visweswara Sastry, D. Chandrasekhar, Geeta Sai Mani, Praveen Reddy Adiyala, Jagadeesh Babu Nanubolu, Kiran Kumar Singarapu, Ram Awatar Maurya
An operationally simple and high
yielding protocol for the synthesis
of polyfunctional pyrazoles has been developed through one-pot, three-component
coupling of aldehydes, 1,3-dicarbonyls, and diazo compounds as well
as tosyl hydrazones. The reaction proceeds through a tandem Knoevenagel
condensation, 1,3-dipolar cycloaddition, and transition metal-free
oxidative aromatization reaction sequence utilizing molecular oxygen
as a green oxidant. The scope of the reaction was studied by varying
the aldehyde, 1,3-dicarbonyl, and diazo component individually.