Denitrogenative dismantling of heteroaromatics by nucleophilic substitution reactions with diazomethyl compounds

Nucleophiles from deprotonation of diazomethyl compounds having diverse electron withdrawing groups react with 4-carboxylato-1,2,3-triazines at the 6-position to extrude dinitrogen and produce diazovinylketoesters compounds with five or six linear contiguous sp2-hybridized carbons, whereas these same nucleophiles react with 4-carboxylato-1,2,3-triazine 1-oxides, also at the 6-position, to form pyrazolines with the expulsion of nitrous oxide and cyanocarboxylate. This disparity is due to the significant difference in reactivity of the nucleophilic addition products.

Tetrabutylammonium iodide-catalyzed oxidative α-azidation of β-ketocarbonyl compounds using sodium azide

We herein report the oxidative α-azidation of carbonyl compounds by using NaN3 in the presence of dibenzoyl peroxide catalyzed by tetrabutylammonium iodide (TBAI). By utilizing these readily available bulk chemicals a variety of cyclic β-ketocarbonyl derivatives can be efficiently α-azidated under operationally simple conditions. Control experiments support a mechanistic scenario involving in situ formation of an ammonium hypoiodite species which first facilitates the α-iodination of the pronucleophile, followed by a phase-transfer-catalyzed nucleophilic substitution by the azide. Furthermore, we also show that an analogous α-nitration by using NaNO2 under otherwise identical conditions is possible as well.

New 5-Aminotetrazole-Based Energetic Polymers: Synthesis, Structure and Properties

An N-glycidyl-5-aminotetrazole homopolymer was synthesized herein by nucleophilic substitution of 5-aminotetrazole heterocycles for chlorine atoms in poly-(epichlorohydrin)-butanediol. Copolymers of N-glycidyl-5-aminotetrazole and glycidyl azide with a varied ratio of energetic elements were synthesized by simultaneously reacting the 5-aminotetrazole sodium salt and the azide ion with the starting polymeric matrix. The 5-aminotetrazole-based homopolymer was nitrated to furnish a polymer whose macromolecule is enriched additionally with energy-rich terminal ONO2 groups and nitrate anions. The structures of the synthesized polymers were characterized by 1H and 13C NMR and IR spectroscopies, elemental analysis and gel-permeation chromatography. The densities were experimentally measured, and thermal stability data were acquired by differential scanning calorimetry. The insertion of aminotetrazole heterocycles into the polymeric chain and their modification via nitration provides an acceptable thermal stability and a considerable enhancement in density and nitrogen content compared to azide homopolymer GAP. By the 1.3-dipolar cycloaddition reaction, we demonstrated the conceptual possibility of preparing spatially branched, energy-rich polymeric binders bearing 5-aminotetrazole and 1,2,3-triazole heterocycles starting from the plasticized azide copolymers. The presence of the aforesaid advantages makes the reported polymers attractive candidates for use as a scaffold of energetic binders.

Spectroscopic evidence for 1,2-diiminoethane - a key intermediate in imidazole synthesis

Simple imines and diimines are common building blocks in organic synthesis, but the compound class is spectroscopically not well characterized. Herein we report the formation of the simplest diimine, namely 1,2-diiminoethane, as well as spectroscopic characterization by cryogenic matrix isolation IR and UV/Vis spectroscopy. Three conformers of 1,2-diiminoethane form after UV irradiation of 1,2-diazidoethane by N₂ extrusion at 3 K in solid argon and can be photochemically interconverted. In a matrix isolation pyrolysis experiment at 600 °C with 1,2-diazidoethane as the starting material we observe hydrogen cyanide and formaldimine as the main decomposition products. All experimental findings are supported by deuterium labeling experiments and B3LYP/6-311++G(2d,2p) calculations. Irradiation of 1,2-diazidoethane in aqueous solution leads to the formation of imidazoles as indicated by NMR spectroscopy and GC-MS analysis. Our results underline the key role of diimines as building blocks in N-heterocyclic chemistry.

Design of new bis-triazolyl structure for identification of inhibitory activity on COVID-19 main protease by molecular docking approach

In the rapidly growing COVID-19 pandemic, designing of new drugs and evaluating their inhibitory action against main targets of corona virus could be an effective strategy to accelerate the drug discovery process and their efficacy towards corona virus disease. Herein, we design new bis-triazolyl probe for an investigation of inhibitory activity towards COVID-19 main protease by Molecular docking approach. The formulated compound has been thoroughly characterized by elemental analysis, NMR (¹H and ¹³C) and complete structure elucidation was achieved via X-ray crystallography. Docking study reveals that newly synthesized compound confers good inhibitory response to COVID-19 main protease as supported by calculated docking score and binding energy. Strong hydrogen bonding and hydrophobic interactions of the newly synthesized compound with several important amino acids of the main protease also helps to explain the potency of the compound to inhibit the main protease. We hope that the present study would help the researcher in the field of Medicinal chemistry and to develop potential drug against the novel corona virus.