Iodine-Catalysed Dissolution of Elemental Gold in Ethanol

Gold is a scarce element in the Earth's crust but indispensable in modern electronic devices. New, sustainable methods of gold recycling are essential to meet the growing eco-social demand of gold. Here, we describe a simple, inexpensive, and environmentally benign dissolution of gold under mild conditions. Gold dissolves quantitatively in ethanol using 2-mercaptoben-zimidazole as a ligand in the presence of a catalytic amount of iodine. Mechanistically, the dissolution of gold begins when I-2 oxidizes Au-0 and forms a [(AuI2)-I-1](-) species, which undergoes subsequent ligand-exchange reactions and forms a stable bis-ligand Au-1 complex. H2O2 oxidizes free iodide and regenerated I-2 returns back to the catalytic cycle. Addition of a reductant to the reaction mixture precipitates gold quantitatively and partially regenerates the ligand. We anticipate our work will open a new pathway to more sustainable metal recycling with the utilization of just catalytic amounts of reagents and green solvents.Peer reviewe

Design, synthesis, in vitro- In vivo biological evaluation of novel thiazolopyrimidine compounds as antileishmanial agent with PTR1 inhibition

The leishmaniasis are a group of vector-borne diseases caused by a protozoan parasite from the genus Leish-mania. In this study, a series of thiazolopyrimidine derivatives were designed and synthesized as novel anti-leishmanial agents with LmPTR1 inhibitory activity. The final compounds were evaluated for their in vitro antipromastigote activity, LmPTR1 and hDHFR enzyme inhibitory activities, and cytotoxicity on RAW264.7 and L929 cell lines. Based on the bioactivity results, three compounds, namely L24f, L24h and L25c, were selected for evaluation of their in vivo efficacy on CL and VL models in BALB/c mice. Among them, two promising compounds, L24h and L25c, showed in vitro antipromastigote activity against L. tropica with the IC50 values of 0.04 mu g/ml and 6.68 mu g/ml; against L. infantum with the IC50 values of 0.042 mu g/ml and 6.77 mu g/ml, respec-tively. Moreover, the title compounds were found to have low in vitro cytotoxicity on L929 and RAW264.7 cell lines with the IC50 14.08 mu g/ml and 21.03 mu g/ml, and IC50 15.02 mu g/ml and 8.75 mu g/ml, respectively. LmPTR1 enzyme inhibitory activity of these compounds was determined as 257.40 mu g/ml and 59.12 mu g/ml and their selectivity index (SI) over hDHFR was reported as 42.62 and 7.02, respectively. In vivo studies presented that L24h and L25c have a significant antileishmanial activity against footpad lesion development of CL and at weight measurement of VL group in comparison to the reference compound, Glucantime (R). Also, docking studies were carried out with selected compounds and other potential Leishmania targets to detect the putative targets of the title compounds. Taken together, all these findings provide an important novel lead structure for the anti-leishmanial drug development.We would like to thank Parasite Bank of Medical School of Manisa Celal Bayar University and Prof. W. N. Hunter (University of Dundee, UK) for the Lm PTR1 construct. The authors extend their appreciation to the Scientific and Technological Research Council of Turkey (TUBITAK) , project no: SBAG-117-S-041 and Izmir Katip Celebi University Scientific Research Coordinatorship, grant no: 2018-ODL-ECZF-0018. This work was partially supported by ARRS (Slovenian Research Agency) pro-gramme grant P1-0201.Scientific and Technological Research Council of Turkey; Izmir Katip Celebi University Scientific Research Coordinatorship [2018-ODL-ECZF-0018]; ARRS (Slovenian Research Agency) programme; [SBAG-117-S-041]; [P1-0201

Selective synthesis of novel quinolones-amino esters as potential antibacterial and antifungal agents : Experimental, mechanistic study, docking and molecular dynamic simulations

A new selective synthesis of novel quinoline carboxamides was developed by the N-alkylation reaction of methyl (2-oxo-1,2- dihydroquinolin-4-yl)-L-alaninate via phase transfer catalysis in a basic medium at room temperature. The compounds were obtained in excellent yields (70-90%) and characterized by H-1, (CNMR)-C-13 spectroscopy and mass spectra. In addition, theoretical studies at B3LYP/6-311G(d,p) level were carried out to explain the observed selectivity of the N-alkylation reaction of compound 2 . The biological activities of the synthesized compounds were studied using some bacterial and fungal strains. The results show that compounds 3h and 3i exhibit stronger antibacterial activity against Bacillus subtilis and Staphyloccocus aureus. Compound 3e showed high antifungal activity against Candida Albicans compared to other substituted quinoline carboxamides. Molecular docking and molecular dynamics studies were also carried out to investigate the binding affinities of some compounds with the target proteins, and the results were in good correlation with the experimental findings. (C) 2021 Elsevier B.V. All rights reserved.Peer reviewe