Novel Thiadiazole-Based Molecules as Promising Inhibitors of Black Fungi and Pathogenic Bacteria: In Vitro Antimicrobial Evaluation and Molecular Docking Studies

Novel 1,3,4-thiadiazole derivatives were synthesized through the reaction of methyl 2-(4-hydroxy-3-methoxybenzylidene) hydrazine-1-carbodithioate and the appropriate hydrazonoyl halides in the presence of a few drops of diisopropylethylamine. The chemical structure of the newly fabricated compounds was inferred from their microanalytical and spectral data. With the increase in microbial diseases, fungi remain a devastating threat to human health because of the resistance of microorganisms to antifungal drugs. COVID-19-associated pulmonary aspergillosis (CAPA) and COVID-19-associated mucormycosis (CAM) have higher mortality rates in many populations. The present study aimed to find new antifungal agents using the disc diffusion method, and minimal inhibitory concentration (MIC) values were estimated by the microdilution assay. An in vitro experiment of six synthesized chemical compounds exhibited antifungal activity against Rhizopus oryzae; compounds with an imidazole moiety, such as the compound 7, were documented to have energetic antibacterial, antifungal properties. As a result of these findings, this research suggests that the synthesized compounds could be an excellent choice for controlling black fungus diseases. Furthermore, a molecular docking study was achieved on the synthesized compounds, of which compounds 2, 6, and 7 showed the best interactions with the selected protein targets.     

Unprecedented [V2O]6+ core of a centrosymmetric thiosemicarbazonato dimer: spontaneous deoxygenation of oxovanadium(IV)

The complex cation [{V(daptsc)(MeOH)}2(mu-O)]2+ [daptsc(2-) = 2,6-diacetylpyridine bis(thiosemicarbazonate)] is the first crystallographically elucidated dimer to possess a [V2O]6+ core, the [V(IV)-O-V(IV)]6+ structural unit, formed by cleavage of the multiple bond in the oxo-cation VO2+, is linear with the oxo group residing on a crystallographic center of inversion, and the temperature dependence of the magnetic data of the dimer is consistent with weak antiferromagnetic coupling of the d1-d1 centers.     

Antibacterial Activities and Molecular Docking of Novel Sulfone Biscompound Containing Bioactive 1,2,3-Triazole Moiety

In this study, a new synthetic 1,2,3-triazole-containing disulfone compound was derived from dapsone. Its chemical structure was confirmed using microchemical and analytical data, and it was tested for its in vitro antibacterial potential. Six different pathogenic bacteria were selected. MICs values and ATP levels were determined. Further, toxicity performance was measured using MicroTox Analyzer. In addition, a molecular docking study was performed against two vital enzymes: DNA gyrase and Dihydropteroate synthase. The results of antibacterial abilities showed that the studied synthetic compound had a strong bactericidal effect against all tested bacterial strains, as Gram-negative species were more susceptible to the compound than Gram-positive species. Toxicity results showed that the compound is biocompatible and safe without toxic impact. The molecular docking of the compound showed interactions within the pocket of two enzymes, which are able to stabilize the compound and reveal its antimicrobial activity. Hence, from these results, this study recommends that the established compound could be an outstanding candidate for fighting a broad spectrum of pathogenic bacterial strains, and it might therefore be used for biomedical and pharmaceutical applications.     

Synthesis of new 1,3,4-thiadiazole and 1,2,3,4-oxathiadiazole derivatives from carbohydrate precursors and study of their effect on tyrosinase enzyme

5-(1,2,3,4-Tetrahydroxybutyl)-2-methylfuran-3-carbohydrazide (2) was condensed with a variety of ketones to afford carbohydrazide derivatives 3-6. Acetylation of 3-5 afforded the acetyl derivatives 7-9, while periodate oxidation of 3-6 afforded the formyl derivatives 10-13. Acid catalyzed condensation of thiosemicarbazide or o-tolylthiosemicarbazide with the prepared aldehydes 10-12 gave thiosemicarbazone derivatives 14-19. Cyclization of the latter with acetic anhydride afforded 4,5-dihydro-1,3,4-thiadiazolyl derivatives 20-25. On the other hand, condensation of p-tosylhydrazine with the prepared aldehydes 10-12 afforded p-tosylhydrazone derivatives 26-28. Cyclization of 26-28 with acetic anhydride afforded 1,2,3,4-oxathiadiazole derivatives 29-31 respectively. Moreover, the obtained results regarding to the effect of some of the prepared compounds on tyrosinase enzyme showed that the majority of these compounds having an inhibitory effect; especially compounds 12, 16, 17, and 28.     

Bicyclic- and tricyclic-beta-lactones via organonucleophile-promoted bis-cyclizations of keto acids: Enantioselective synthesis of (+)-dihydroplakevulin

A highly diastereoselective, nucleophile-promoted bis-cyclization process, employing readily available and tractable keto acid substrates, is described. This methodology provides concise access to bicyclic- and tricyclic-beta-lactones bearing tertiary carbinol centers and quaternary carbons, greatly extending the scope of previous routes to bicyclic-beta-lactones from aldehyde acid substrates. The utility of the method was demonstrated by application to an enantioselective synthesis of (+)-dihydroplakevulin A. This and related processes may be revealing a subtle interplay between [2+2] cycloaddition and nucleophile-catalyzed aldol lactonization (NCAL) reaction manifolds.     

Site‐ and Regioselectivity of the Reaction of Hydrazonoyl Chlorides with Perimidine Ketene Aminal. Antimicrobial Evaluation of the Products

Reaction of hydrazonoyl chlorides with perimidine ketene aminal derivative in dioxane in the presence of triethylamine afforded either pyrrolo[1,2‐a]perimidines or pyrazolyl perimidines depending on the type of hydrazonoyl chloride used. The reaction was found to be site‐ and regioselective according to the suggested mechanism. The structure of the newly synthesized compounds was established on the basis of spectral data and elemental analyses. In addition, the antimicrobial activity of the newly synthesized compounds was evaluated, and the results showed moderate activity of all compounds against the bacterial species.     

Novel silicon-carbon fullerene-like cages

We present model calculations of kinetic energy releases and fission barriers in asymmetric fission of C₆₀^{r +} ions, using a simple electrostatic model where the fragments are treated as conducting spheres. The kinetic energy releases are calculated using two different approaches for deducing the radii of the spheres. Both approaches give results in qualitative agreement with experimental results. The fission barriers, on the other hand, depend strongly on the model radii and the activation energies for neutral fragment emission. A comparison between the model calculations shows that the choice of the finite size of the smaller fragments become important as r increases and have large influences on the prediction for the C₆₀^{r +} stability limit. The competition between neutral (evaporation) and charged-fragment emission (fission) are discussed within a static over-the-barrier model for electron transfer between conducting spheres.Received: 10 December 2003, Published online: 27 January 2004PACS: 34.70. + e Charge transfer - 36.40.Qv Stability and fragmentation of clusters - 36.40.Wa Charged clusters