Synthesis of Antimicrobial Benzo[1,2,4]triazoloazepinium Salts and Tetrahydronaphtho[1,2-e][1,2,4]triazines by Polar [3⁺ + 2] and [4 + 2]-Cycloaddition Reactions

Abstract

Novel annulated azaheterocycles of benzo­[1,2,4]­triazoloazepine and tetrahydronaphtho­[1,2-e]­[1,2,4]­triazine derivatives have been synthesized. Treatment of 2-diazenyl-1,2,3,4-tetrahydronaphthalen-2-yl acetates with BF3·Et2O generates 1-aza-2-azoniaallenium cation intermediates (or azocarbenium ions), which are intercepted by nitriles via cascade polar [3+ + 2]-cycloaddition/rearrangement reactions to afford benzo­[1,2,4]­triazoloazepinium salts. These literature unprecedented fused tricycle compounds have been shown to exhibit antimicrobial activity against Gram-positive Staphylococcus aureus with in silico docking studies, suggesting that they may exhibit their antibiotic activity through inhibition of DNA gyrase. Additionally, when ethyl 2-(1-acetoxy-1,2,3,4-tetrahydronaphthalen-2-yl)­diazene-1-carboxylate is employed, the reaction with BF3·Et2O produces 1,2-diaza-1,3-diene, which reacts with nitriles via a diaza-Diels–Alder reaction with inverse electron demand, leading to ethyl tetrahydronaphtho­[1,2-e]­[1,2,4]­triazine carboxylates. The DFT calculation has been performed to further prove the D–A reaction speculation.

Anticancer and Antimicrobial Activity of Some New 2,3-Dihydro-1,5-benzodiazepine Derivatives

“…In a related report recorded, similar benzodiazepines tested have been found to be efective against similar microbial bioflms [50,51]. Tese abilities of the benzodiazepines have been alluded to by the variation in the sensitivity of the bioflm to these benzodiazepine derivatives.…”

C–O Coupling of Hydrazones with Diacetyliminoxyl Radical Leading to Azo Oxime Ethers—Novel Antifungal Agents

“…In general, free-radical functionalization of hydrazones with the formation of azocompounds is less developed compared to methods based on electrophilic attack of hydrazone carbon atoms, such as Michael-type reactions [20][21][22][23], chlorination [24], alkoxylation, or cyanation [25]. Geminal azoacetates are synthesized by the oxidation of hydrazones with Pb(OAc) 4 [26][27][28]. In the present work (Scheme 1C), diacetyliminoxyl was used as the only necessary reagent for high-yielding oxidative C-O coupling with the broad scope of both ketohydrazones and aldehyde-derived hydrazones at room temperature.…”