Tuning of chemo- and regioselectivities in multicomponent condensations of 5-aminopyrazoles, dimedone, and aldehydes

The three-component condensation of 5-aminopyrazoles, aromatic aldehydes, and cyclic 1,3-diketones to selectively obtain three distinct reaction products, pyrazolo[3,4-b]quinolin-5-ones, pyrazolo[5,1-b]quinazolin-8-ones, and pyrazolo[4,3-c]quinolizin-9-ones is presented. The tricyclic heterocycles could give moderate to good isolated yields.