A controllable synthesis of trisubstituted imidazoles and pyrroles has been developed through rhodium(II)-catalyzed regioselective annulation of N-sulfonyl-1,2,3-trizaoles with β-enaminones. The imidazole ring was formed through 1,1-insertion of N-H bond to α-imino rhodium carbene and subsequential intramolecular 1,4-conjugate addition when α-carbon atom of amino group bearing with methyl, whereas utilizing phenyl substituent constructed pyrrole ring via intramolecular nucleophilic addition. Features such as mild conditions, good functional groups tolerance, gram-scale synthesis, and valuable transformations of the products qualified this unique protocol as an efficient tool for the synthesis of N-heterocycles.

Heterocycles are unique precursors for the synthesis of various pharmaceuticals and agrochemicals particularly those possessing N- or O- moieties. The development of methods to prepare heterocycles is of great importance in synthesis of organic compounds, especially the heterocycles which can be found in natural products. The synthesis of nitrogen and oxygen containing heterocycles viz. coumarins, dihydropyrimidinones, imidazoles, isoxazoles and benzimidazoles represented an attractive and demanding work for chemists as these nucleus has found extensive applications in several fields such as material science, analytical chemistry and most importantly in medicinal chemistry. Organic synthesis has been attracted towards the development of new environmental friendly procedures to achieve the goals of green chemistry. The fundamental aspects of green chemistry are use of biocatalysts and environmental benign solvents under mild conditions. The present review article summarized the green synthetic methods and biological activities of nitrogen and oxygen containing heterocycles.

A new class of tetrasubstituted imidazole based compounds was synthesized using a multicomponent one-pot synthesis scheme through a cyclo condensation reaction of benzil, aromatic primary amines, aldehydes and ammonium acetate in glacial acetic acid. The synthesized compounds have been analyzed and characterized by melting point, color, conductivity method, CHN analysis, FT-IR, and UV-Visible. The reaction proceeding was examined by TLC after regular intervals of period. To test biological activity, the synthesized compounds have been examined against various bacterial strains. From the analysis of the antibacterial activity of these synthesized compounds demonstrated that all three imidazole compounds have considerable to significant activity against the strains, and compound K2 was found potent comparatively.

The construction of carbon-carbon bonds by direct involvement of two unactivated carbon-hydrogen bonds, without any directing group, ensures an high atom economy of the entire process. Here it is described a simple protocol for the Pd(II)/Cu(II)-promoted intermolecular cross-dehydrogenative coupling (CDC) of 5-arylimidazoles, benzimidazoles, benzoxazole and 4,5-diphenylimidazole at their C-2 position with functionalized styrenes. This specific CDC, known as Fujiwara-Moritani reaction or oxidative Heck coupling, allowed also the C-4 alkenylation of the imidazole nucleus when both 2 and 5 positions are occupied.