Isocyanide based [4+1] cycloaddition reactions: an indispensable tool in multi-component reactions (MCRs).

The advent of cycloaddition reactions in the synthesis of heterocycles and their ever burgeoning applications in the fields of material chemistry, catalysis and drugs have been a profound scientific development. In particular, isocyanide based cycloaddition reactions have been harbingers of an exciting new chapter in the realms of organic synthesis. The emergence of numerous synthetic protocols utilizing formal cycloaddition of isocyanides with conjugated heterodienes has unleashed countless opportunities to design and synthesize diverse heterocyclic scaffolds. To date, there has not been any exclusive review on a formal [4+1] cycloaddition involving isocyanides. The present review highlights the journey of formal [4+1] cycloaddition reactions of isocyanides with diverse electrophilic substrates viz. oxadienes, azadienes, thioacyl imines, alkylidene amides, alkylidene hydrazines, α,ß-unsaturated nitro compounds, α-thioxothioamides, nitroso alkenes, acyl imines, vinyl ketenes, vinyl isocyanates, etc. to afford functionalized pyrroles, imidazoles, furans, oxazoles, pyrazoles, etc.

Combined 3D-QSAR and Molecular Docking Study for Identification of Diverse Natural Products as Potent Pf ENR Inhibitors.

An in-house library of 200 molecules from natural plant products was designed in order to evaluate their binding to Plasmodium ACP enoyl reductase (ENR), a promising biological target for antimalarial chemotherapeutics. The binding site of PfENR was explored computationally and the molecules were docked using AutoDock. Furthermore, the top-ranked scaffolds from docking studies were also compared with known PfENR inhibitors using 3D-QSAR. To this effect, a 3D-QSAR model was derived from a set of experimentally established PfENR inhibitors, using Comparative Molecular Force Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA). The best optimum CoMFA model exhibited a leave-one-out correlation coefficient (q2) and a noncross- validated correlation coefficient (r2) of 0.630 and 0.911, respectively. The result of this cumulative approach proposed five structurally distinct natural products as potent PfENR inhibitors. This study may lay a stepping stone towards Functional oriented synthesis (FOS) of novel PfENR inhibitors in future.

3D-QSAR Selectivity Analysis of 1-Adamantyl-3-Heteroaryl Urea Analogs as Potent Inhibitors of Mycobacterium tuberculosis.

A 3D-QSAR selectivity analysis of 53 adamantyl heteroaryl urea derivatives active against M. tuberculosis is reported. These analogs inhibit Mycobacterial Membrane Protein Large 3 (MmpL3), a proposed transporter for cell wall mycolic acids. However, these analogs also exhibit affinity towards human soluble epoxide hydrolase (sEH) enzyme, making them pharmacologically undesirable. Thus, COMFA and CoMSIA selective studies viz ligand and receptor-based alignment has been described to evaluate key pharmacophoric structural features that may possibly play a crucial role for selective inhibition. This hypothesis was experimentally validated and successfully tested on four novel adamantyl urea based derivatives with known biological activity. Therefore, this approach may pave way to novel specific inhibitors in tuberculosis drug discovery process.