Environmentally friendly, microwave-assisted synthesis of 5-substituted 1 H-tetrazoles by recyclable CuO nanoparticles via (3+2) cycloaddition of nitriles and NaN3

Catalytic Tetrazole Synthesis via [3+2] Cycloaddition of NaN3 to Organonitriles Promoted by Co(II)-complex: Isolation and Characterization of a Co(II)-diazido Intermediate

The [3+2] cycloaddition of sodium azide to nitriles to give 5-substituted 1H-tetrazoles is efficiently catalyzed by a Cobalt(II) complex (1) with a tetradentate ligand N,N-bis(pyridin-2-ylmethyl)quinolin-8-amine. Detailed mechanistic investigation shows the intermediacy of the cobalt(II) diazido complex (2), which has been isolated and structurally characterized. Complex 2 also shows good catalytic activity for the synthesis of 5-substituted 1H-tetrazoles. These are the first examples of cobalt complexes used for the [3+2] cycloaddition reaction for the synthesis of 1H-tetrazoles under homogeneous conditions.

Copper Catalyzed Synthesis of Heterocyclic Molecules via C-N and C-O Bond Formation under Microwaves: A Mini-Review

Heterocyclic moieties play a significant role in the field of drug discovery. C-N and C-O bond formation reactions are the primary synthetic sequence for the generation of heterocyclic molecules. The generation of C-N and C-O bonds involves the use of mostly Pd or Cu catalysts although other transition metal catalyst's are also involved. However, in C-N and C-O bond formation reactions, several problems were faced such as catalytic systems containing costly ligands, lack of substrate scope, lots of waste generation, and high temperature conditions. So it is imperative to uncover new eco-friendly synthetic strategies. In view of enormous drawbacks, it is important to develop an alternate microwave-assisted synthesis of heterocycles via C-N and C-O bond formation, which provides a short reaction time, tolerance for functional groups, and less waste production. Numerous chemical reactions have been accelerated using microwave irradiation which provides a cleaner reaction profile, lower energy consumption, and higher yields. This review article highlights a comprehensive overview on the potential application of microwave assisted synthetic routes for the synthesis of diverse heterocycles via mechanistic pathways covering the year ranges from 2014 to 2023, along with possible biological interests.