In the present work, a new protocol was developed for the synthesis of 2,4,5-triaryl imidazoles via three component condensation of aryl aldehyde, benzil and ammonium acetate in the presence of 1-butyl-3-methyl-imidazolium hexafluoro phosphate ([BMIM][PF6]) as a catalyst under reflux in ethanol. The present protocol has many beneficial advantages such as excellent yields, easy workup procedure, green catalyst and purification of the targeted molecules without the use of column chromatography which increases the green chemistry value of the present work.

In this work we report, aluminized polyborate catalyzed facile and efficient one-pot four component Hantzsch synthesis of 1,8-dioxo-decahydroacridines using substituted aromatic aldehydes (1 mmol), dimedone (2 mmol) and ammonium acetate (1.5 mmol) at 95-100oC under solvent-free condition. The prominent advantages of this methodology are good product yields (85-95%), eco-friendliness, mild reaction conditions and use of inexpensive catalyst. The structures of the targeted molecules were examined by FT-IR, 1H-NMR and mass spectral techniques.

The present paper elicits the zinc oxide nanoparticles-assisted synthesis of a new series of seven-membered 1,4-diazepine heterocyclic compounds as potent lead scaffolds. Structures of synthesized compounds were corroborated using spectroanalytical techniques viz, FT-IR, 1H, 13C NMR, Mass, and elemental analysis. Also, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), Energy dispersive x-ray analysis (EDAX), powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FT-IR) were used to establish the structure and morphology of the synthesized nanocatalyst. The clean workup procedure, high to excellent yields, relatively short reaction times, and high atom economy are the incredible advantages associated with the protocol.

Wide range of 2,4,5-trisubstituted imidazoles were synthesized using eco-friendly, readily available, inexpensive Zn(OAc)2•2H2O (5 mol%) under solvent-free conditions in moderate to excellent yields by condensation from aldehyde, ammonium acetate and benzil at 70 0C. The optimized reaction parameters were successfully applied for the synthesis of divergent 1,2,4,5-tetrasubstitued imidazoles using aromatic amine as fourth component. All the imidazole derivatives were sufficiently characterized by IR, NMR and Mass spectral analyses.

One-pot synthesis of highly substituted pyridines has been demonstrated via multicomponent reaction of aldehydes, malononitrile and thiophenol using Mg-Al hydrotalcite as a solid base and reusable catalyst. The catalytic activity is intimately connected to the basicity of the catalyst. The best activities were observed with the Mg/Al: 5 catalyst. The catalyst could be reused for further run without a significant loss in activity. The protocol was also applicable for various aromatic aldehydes which affords desired product in good to excellent yield.

Synthesis of pyrano-chromenes and pyrano-pyrans was developed by three-component reactions of kojic acid and aromatic aldehydes with dimethone and malononitrile, catalyzed with nano-Bi2O3-ZnO and nano-ZnO, respectively. Reactions proceeded smoothly and the corresponding heterocyclic products were obtained in good to high yields. Nano ZnO and nano Bi2O3-ZnO were prepared by sol-gel method and characterized by X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Supporting Bi3+ on ZnO nanoparticles as Bi2O3, is the main novelty of this work. The simple reaction procedure, easy separation of products, low catalyst loading, reusability of the catalyst are some advantageous of this protocol.

The conventional and microwave assisted multicomponent synthesis of disubstituted 1,2,3-triazoles from terminal alkynes and in situ generated organic azide using copper apatite catalyst in water is reported. The catalytic activity is intimately connected to the basicity of the catalyst. The best activities were observed with the copper hydroxyapatite. The catalyst could be used ten times without further treatment and activation under controlled microwave heating. The protocol was also applicable for various alkynes and halides which affords desired product in good to excellent yield.

An efficient and practical, three-component one-pot condensation reaction between 1, 2-phenylenediamine, 2-mercaptoacetic acid and aromatic aldehydes in ionic liquids have been reported for the synthesis of 1-aryl-1H, 3H-thiazolo [3, 4-a] benzimidazoles derivatives in excellent yields.