Chemoselective Three Component Reactions of 3-Aminopyrazoles, Aldehydes and Malononitrile: Optimize the Structures and Compute the Energies of Possible Tautomers

A chemoselective synthesis of 7-amino-5-aryl-2-hydroxy-3-(aryldiazenylpyrazolo[1,5-a]pyrimidine-6- carbonitriles and 4-((7-amino-6-cyano-2-hydroxy-5-arylpyrazolo[1,5-a]pyrimidine-3-yl)diazenyl)benzenesulfonamides through three-component reaction of 3-aminopyrazoles, aldehydes and malononitrile in the presence of base catalysts such as sodium acetate, pyridine and high surface area MgO is reported. 3-Amino pyrazoles were prepared by refluxing of ethyl(arylazo) cyanoacetates with hydrazine hydrate in ethanol. Structures of the new compounds were established by their spectral data and theoretical results. Density Functional Theory (DFT) calculations have been performed to optimize the structure of products. The theoretical results are in good agreement with experimental findings. The theoretical results are compared with the experimetal data. DFT calculations reveal that the enol form of 6 is the most stable molecule.