Synthesis and biological activity of novel amidrazones incorporating 5-nitroimidazole, ciprofloxacin, and 7-chloro-4-piperazinylquinoline

First Exclusive Stereo- and Regioselective Preparation of 5-Arylimino-1,3,4-Selenadiazole Derivatives: Synthesis, NMR analysis, and Computational Studies

Isoselenocyanates are valuable coupling partners required for preparing key chemical intermediates and biologically active molecules in an accelerated and effective way. Likewise, (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides have been employed in numerous one-step heteroannulation reactions to assemble the structural core of several various kinds of heterocyclic compounds. Here, we describe the inverse electron demand 1,3-dipolar cycloaddition reaction of isoselenocyanates with a variety of substituted (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides to generate, regioselectively and stereoselectively, a series of 5-arylimino-1,3,4-selenadiazole derivatives comprising a multitude of functional groups on both aryl rings. The synthetic method features gentle room-temperature conditions, wide substrate scope, and good to high reaction yields. The selenadiazoles were separated by gravity filtration in all instances and chemical structures were validated by multinuclear NMR spectroscopy and high accuracy mass spectral measurements. First conclusive molecular structure elucidation of the observed 5-arylimino-selenadiazole regioisomer was verified by single-crystal X-ray diffraction analysis. Crystal-structure measurement was successfully carried out on (Z)-1-(4-(4-iodophenyl)-5-(p-tolylimino)-4,5-dihydro-1,3,4-selenadiazol-2-yl)ethan-1-one and (Z)-1-(5-((4-methoxyphenyl)imino)-4-(4-(methylthio)phenyl)-4,5-dihydro-1,3,4-selenadiazol-2-yl)ethan-1-one. Likewise, the (Z)-geometry of the hydrazonoyl chloride reactant was proven by X-ray diffraction studies. As representative examples, crystal-structure determination was carried out on (Z)-2-oxo-N-phenylpropanehydrazonoyl chloride and (Z)-N-(3,5-bis(trifluoromethyl)phenyl)-2-oxopropanehydrazonoyl chloride. Density functional theory calculations at the B3LYP-D4/def2-TZVP level were conducted to support the noted experimental findings and suggested mechanism.

First X-ray Crystal Structure Characterization, Computational Studies, and Improved Synthetic Route to the Bioactive 5-Arylimino-1,3,4-thiadiazole Derivatives

N-arylcyanothioformamides are useful coupling components for building key chemical intermediates and biologically active molecules in an expedited and efficient manner. Similarly, substituted (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides have been utilized in numerous one-step heteroannulation reactions to assemble the structural core of several different types of heterocyclic compounds. Herein, we demonstrate the effectiveness of the reaction of N-arylcyanothioformamides with various substituted (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides to produce, stereoselectively and regioselectively, a range of 5-arylimino-1,3,4-thiadiazole derivatives decorated with a multitude of functional groups on both aromatic rings. The synthetic methodology features mild room-temperature conditions, large substrate scope, wide array of functional groups on both reactants, and good to high reaction yields. The products were isolated by gravity filtration in all cases and structures were confirmed by multinuclear NMR spectroscopy and high accuracy mass spectral analysis. Proof of molecular structure of the isolated 5-arylimino-1,3,4-thiadiazole regioisomer was obtained for the first time by single-crystal X-ray diffraction analysis. Crystal-structure determination was carried out on (Z)-1-(5-((3-fluorophenyl)imino)-4-(4-iodophenyl)-4,5-dihydro-1,3,4-thiadiazol-2-yl)ethan-1-one and (Z)-1-(4-phenyl-5-(p-tolylimino)-4,5-dihydro-1,3,4-thiadiazol-2-yl)ethan-1-one. Similarly, the tautomeric structures of the N-arylcyanothioformamides and (Z)-geometries of the 2-oxo-N-phenylpropanehydrazonoyl chloride coupling partners were proven by X-ray diffraction studies. As representative examples, crystal-structure determination was carried out on (4-ethoxyphenyl)carbamothioyl cyanide and (Z)-N-(2,3-difluorophenyl)-2-oxopropanehydrazonoyl chloride. Density functional theory calculations at the B3LYP-D4/def2-TZVP level were carried out to rationalize the observed experimental findings.

A Review of the Biological Activity of Amidrazone Derivatives

Amidrazones are widely used in chemical synthesis, industry and agriculture. We compiled some of the most important findings on the biological activities of amidrazones described in the years 2010-2022. The data were obtained using the ScienceDirect, Reaxys and Google Scholar search engines with keywords (amidrazone, carbohydrazonamide, carboximidohydrazide, aminoguanidine) and structure strategies. Compounds with significant biological activities were included in the review. The described structures derived from amidrazones include: amidrazone derivatives; aminoguanidine derivatives; complexes obtained using amidrazones as ligands; and some cyclic compounds obtained from amidrazones and/or containing an amidrazone moiety in their structures. This review includes chapters based on compound activities, including: tuberculostatic, antibacterial, antifungal, antiparasitic, antiviral, anti-inflammatory, cytoprotective, and antitumor compounds, as well as furin and acetylocholinesterase inhibitors. Detailed information on the compounds tested in vivo, along the mechanisms of action and toxicity of the selected amidrazone derivatives, are described. We describe examples of compounds that have a chance of becoming drugs due to promising preclinical or clinical research, as well as old drugs with new therapeutic targets (repositioning) which have the potential to be used in the treatment of other diseases. The described examples prove that amidrazone derivatives are a potential source of new therapeutic substances and deserve further research.

Functionalized Nitroimidazole Scaffold Construction and Their Pharmaceutical Applications: A 1950–2021 Comprehensive Overview

Nitroimidazole represents one of the most essential and unique scaffolds in drug discovery since its discovery in the 1950s. It was K. Maeda in Japan who reported in 1953 the first nitroimidazole as a natural product from Nocardia mesenterica with antibacterial activity, which was later identified as Azomycin 1 (2-nitroimidazole) and remained in focus until now. This natural antibiotic was the starting point for synthesizing numerous analogs and regio-isomers, leading to several life-saving drugs and clinical candidates against a number of diseases, including infections (bacterial, viral, parasitic) and cancers, as well as imaging agents in medicine/diagnosis. In the present decade, the nitroimidazole scaffold has again been given two life-saving drugs (Delamanid and Pretomanid) used to treat MDR (multi-drug resistant) tuberculosis. Keeping in view the highly successful track-record of the nitroimidazole scaffold in providing breakthrough therapeutic drugs, this comprehensive review focuses explicitly on presenting the activity profile and synthetic chemistry of functionalized nitroimidazole (2-, 4- and 5-nitroimidazoles as well as the fused nitroimidazoles) based drugs and leads published from 1950 to 2021. The present review also presents the miscellaneous examples in each class. In addition, the mutagenic profile of nitroimidazole-based drugs and leads and derivatives is also discussed.

Synthesis, Characterization, and Antimicrobial Evaluation of New Furan-2-Carboxamide Derivatives

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A new series of furan-2-carboxamide and 5-bromofuran-2-carboxamide derivatives have been prepared in good yields using simple procedures. Our strategy was to synthesize compounds containing functional groups that are known to exhibit significant bioactivity, such as amide (8–15), 2,4-dinitrophenylhydrazone (8a–15a), and thiosemicarbazone (8b– 15b). These newly synthesized compounds have been characterized with the aid of a number of spectroscopic techniques including 1H-NMR, 13C-NMR, IR, and mass spectrometry, in addition two x-ray structures were measured. Antibacterial and antifungal activity of prepared compounds was investigated; antifungal results indicated that compound 8a is the most active whereas compounds 15 and 9b showed moderate activity. Similarly, results of antibacterial testing revealed that most of the prepared compounds exhibit low activity, while compounds containing 2,4-dinitrophenylhydrazone moiety (9a-14a) are the most active towards E. Coli strain.

Structural and biological survey of 7-chloro-4-(piperazin-1-yl)quinoline and its derivatives

The 7-chloro-4-(piperazin-1-yl)quinoline structure is an important scaffold in medicinal chemistry. It exhibited either alone or as hybrid with other active pharmacophores diverse pharmacological profiles such as: antimalarial, antiparasitic, anti-HIV, antidiabetic, anticancer, sirtuin Inhibitors, dopamine-3 ligands, acetylcholinesterase inhibitors, and serotonin antagonists. In the presented review, a comprehensive discussion of compounds having this structural core is surveyed and illustrated.

Design, Synthesis and Characterization of Novel Isoxazole Tagged Indole Hybrid Compounds

Sixteen new isoxazole tagged indole compounds have been synthesized via copper (I) catalyzed click chemistry of the aryl hydroxamoyl chloride and an indole containing alkyne moiety. The chemical structure of the synthesized compounds has been established using various physicochemical techniques. X-ray single crystal analysis of Ethyl 1-((3-phenylisoxazol-5-yl) methyl)-1H-indole-2-carboxylate (8a) has been analyzed. All compounds were tested for their antibacterial and anticancer activities. The activities for the new compounds were weak against both bacterial strains and the cancer cell lines.

Nitroimidazole-containing compounds and their antibacterial and antitubercular activities

Infections especially tuberculosis caused by various bacteria including mycobacteria result in millions of lives every year, but the control of bacterial infections is challenged by the limitation of effective pharmaceuticals against drug-resistant pathogens. Nitroimidazoles belong to a group of nitroheterocyclic compounds that have broad-spectrum activity against a series of organisms such as mycobacteria, anaerobic Gram-positive and Gram-negative bacteria, and some of them have already been used in clinics or under clinical trials for the treatment of infectious diseases. In this review, we made an overview of the recent advances in nitroimidazole-containing compounds with antibacterial and antitubercular activity in the recent 20 years.