Microwave-assisted multicomponent reaction for the synthesis of 2-amino-4,6-diphenylpyridine-3-carbonitrile derivatives using ZnO nanoparticles as a catalyst

Functionalized nitrogen-heterocycles play a predominant role in medicinal chemistry. The pyridine nucleus is prevalent in numerous natural products and is extremely important in the chemistry of biological systems. It plays a key role catalyzing both biological and chemical systems. Many pyridine derivatives are of commercial interest and find application in areas where bioactivity is important, as in medicinal drugs [1]. Some of them have been used as herbicides, fungicides, pesticides, medicines, and dyes. Several cyanopyridine moiety compounds show interesting pharmacological and chemotherapeutic activities, such as anticancer, antitubercular, antimicrobial, etc. [2,3]. In the current project, a green and convenient approach to the synthesis of 2-amino-4,6-diphenylpyridine-3-carbonitrile via four-component reaction of malononitrile, aromatic aldehydes, acetophenone and ammonium acetate in the presence of ZnO nanoparticles as a highly effective heterogeneous catalyst under solvent free and microwave irradiation conditions is described (scheme 1). This method has the advantage of short routine, high yields and being environmentally-friendly. The catalyst could be quantitatively recovered from the reaction mixture by simple filtration and reused at least eight times with almost consistent activity.

[1] N.R. Challa, B. Mamidisetty, M.R. Ghanta and P.R. Padi, J. Saudi. Chem. Soc., 2014, 18, 513-519. [2] H. Sheibani, K. Saidi, M. Abbasnejad, A. Derakhshani and I. Mohammadzadeh, Arabian J. Chem., 2016, 9, S901-S906. [3] S.S. Mansoor, K. Aswin, K. Logaiya and S. Sudhan, J. Saudi. Chem. Soc., 2016, 20, 517-522.