Aryl Thiourea Research Articles

Different Aryl Thiourea Compounds as Flotation Collectors in a Lead–Zinc Sulfide Mixed System

The primary coexisting mineral with galena is sphalerite. Hence, it is critical to selectively separate galena from sphalerite by flotation. In this work, thiourea and related derivatives as potential flotation collectors for separating galena from sphalerite were investigated. Thiourea and its related derivatives were found to be effective selective collectors in batch flotation studies of a single mineral, with 1,1-diphenylthiourea (11DTA) emerging as the best choice. Galena has superior floatability compared to sphalerite in the presence of 11DTA, and the recovery difference between the two minerals at pH 8 (where the 11DTA concentration is 5 × 10−6 mol/L) is around 38%. This was revealed in batch flotation studies using artificial mixed minerals. Moreover, the findings from the measurements of adsorption amount, FTIR, zeta potential and XPS revealed that 11DTA has a strong adsorption on galena yet a relatively weak adsorption on sphalerite. Additionally, DFT calculations demonstrated that sphalerite exhibits stronger hydrophilicity than galena, and 11DTA possessed a better affinity for galena.

Synthesis, characterization and catalytic activities of Zn(II) and Cd(II) complexes supported by unsymmetrical aryl thiourea ligands

AbstractWe report a series of Zn(II) and Cd(II) metal complexes [L12(ZnCl2)] (1), [L12(ZnBr2)] (2), [L12(CdCl2)] (3), [L12(CdI2)] (4), [L22(ZnCl2)] (5), [L22(ZnBr2)] (6), [L22(ZnI2)] (7), [L22(CdCl2)] (8), [L32(CdCl2)] (9) and [L42(ZnBr2)] (10), synthesized using various unsymmetrical aryl thiourea ligands: 1‐(2,6‐diisopropylphenyl)‐3‐phenylthiourea (L1), 1‐mesityl‐3‐phenylthiourea (L2), 1‐(2‐fluorophenyl)‐3‐phenylthiourea (L3) and symmetrical 1,3‐bis(2‐fluorophenyl)thiourea (L4). The ligands and metal complexes were characterized by 1H, 13C{1H} NMR, FT‐IR analysis. Solid‐state structures of the zinc and cadmium metal complexes (1–8) were established using the single‐crystal diffraction analysis technique. Furthermore, the catalytic activities of the Zn(II) complexes towards hydroboration of aldehydes and ketones (‐C=O) as substrates were studied. Excellent yields of the corresponding boronate esters were achieved.

Rapid assembly of structurally diverse cyanamides and disulfanes via base-mediated aminoalkylation of aryl thiourea

A general one-pot method for the preparation of cyanamides and disulfanes from aryl thioureas and halides via a base-mediated reaction was accomplished.

Thermally Activated Aryl Thioureas as Brønsted Acid Catalysts for C–C Bond Forming Reactions: Synthesis of Symmetrical Trisubstituted Methanes

AbstractA study on relative catalytic efficacy of 1,3-diaryl thioureas has revealed that 1-[3,5-bis(trifluoromethyl)phenyl]-3-phenylthiourea is an efficient alternative to the Schreiner’s thiourea catalyst (STC) for acid-catalyzed activation of carbonyl compounds in the synthesis of symmetrical trisubstituted methanes (TRSMs) at an elevated temperature. Since the preparation of STC involves the use of toxic thiophosgene, the 1-[3,5-bis(trifluoromethyl)phenyl]-3-phenylthiourea represents an easily accessible and simpler alternative. Strikingly, the temperature-assisted reaction showed significantly shorter reaction time in comparison to photoirradiation in the thiourea-catalyzed Friedel–Crafts type reaction of indole with aldehydes. Simple reaction set-up and excellent yields are some of the highlights of the reported method.

An Efficient and Practical Construction of S−N Bond from Aryl Thioureas and Amines under Metal‐Free Conditions

AbstractAn efficient and practical construction of S−N bond from aryl thioureas and amines under mild and metal‐free conditions is reported. A series of sulfenamides was obtained smoothly from aryl thioureas and amines (mainly secondary amines) through cross dehydrogenation coupling reaction (CDC) in the presence of phenyliodine(III) diacetate. The protocol features easily available starting materials, easy and odorless performance, mild reaction conditions, good yields, and a broad substrate scope, illustrating its synthetic value for the synthesis of diverse biologically or pharmaceutically relevant compounds.

Generation of Thiyl Radicals from Air-Stable, Odorless Thiophenol Surrogates: Application to Visible-Light-Promoted C–S Cross-Coupling

AbstractThe synthetic versatility of thiophenols is offset by their air-sensitivity and foul odor. It is demonstrated that S-aryl isothiouronium salts can be used as precursors to thiyl radicals, extending the practical benefits of these air-stable, odorless salts from ionic to single electron manifolds. The isothiouronium salts are accessed via Ni-catalyzed cross-coupling of (hetero)aryl iodides and thiourea and are isolated as free-flowing solids following anion exchange. Judicious choice of a redox-innocent counteranion enables use of these convenient thiophenol surrogates in radical processes, as is exemplified by the synthesis of non-symmetrical diaryl thioethers via light-promoted S-arylation.

Cs2CO3-Promoted Hydrothiolation of Alkynes with Aryl Thioureas: Stereoselective Synthesis of (Z)-Vinyl Sulfides.

A metal-free Cs2CO3-promoted hydrothiolation of alkynes with aryl thioureas for stereoselective synthesis of (Z)-vinyl sulfides has been reported. Vinyl thioethers were obtained without a metal catalyst in good yields via anti-Markovnikov and cis addition. The protocol features a broad substrate scope of the starting materials, high atom economy, good yields, and exclusive stereoselectivity, showing potential synthetic value for the synthesis of a diversity of (Z)-vinyl thioethers.

Synthesis and characterization of novel acylthiourea compounds used in ions recognition and sensing in organic media

A series of novel N-acyl-N’-aryl thiourea derivatives were designed and prepared with the aim to develop dual responsive receptors for anions and cations. The structure of the new products was confirmed by NMR spectroscopy (13C and 1H), elemental analysis, and IR spectroscopy. Their thermal stability was studied by thermogravimetric analysis (TG) and it was found that these acyl thiourea derivatives are stable up to 160 °C. The ion recognition and sensing properties of the acyl thiourea compounds were investigated by UV–VIS absorption spectroscopy in organic media upon the addition of various salts. The UV–VIS studies revealed that these acyl thiourea derivatives are able to sense biological important ions such as fluoride and copper (II) ions.

Synthesis, Anti-Bacterial and Anti-biofilm Activity of New Iminothiazolidinones

Aim: Iminothiazolidinones are one of the important classes of heterocyclic compounds and they occupied unique position in medicinal chemistry due to their wide range of biological and pharmaceutical properties. In view this potential activity, it has been planned to synthesize a series of New Iminothiazolidinones on benzimidazole nucleus and to study their biological activity.
 Methodology: Iminothiazolidinones and 1,1 dioxide- Iminothiazolidinones were synthesized with a simple and efficient method of cyclic condensation of aryl thiourea containing benzimidazole and thiazole with chloroacetic acid .This method requires mild reaction conditions, simple procedure and gives good yield.
 Results: The structures of the synthesized compounds were assessed by Infrared, NMR and Mass spectroscopic methods. The synthesized compounds were screened for their antibacterial and biofilm inhibitory activities against selected multi drug resistant bacterial strains.
 Conclusion: In accordance with the results obtained, growth inhibition was found significant with compounds 5d and 5e. Methicillin resistant Staphylococcus aureus (MRSA), Vancomycin resistant Enterococcus (VRE), and extended spectrum β‑lactamase (ESBL) producing Klebsiella pneumoniae have shown varied susceptibility towards these compounds. The Biofilm inhibition Concentrations (BFIC) of compounds 5e and 5d are 3.22 ±0.56 and 6.58 ±1.5 µg/mL respectively were noted against MRSA.

Novel Access to Known and Unknown Thiourea Catalyst via a Multicomponent‐Reaction Approach

AbstractThioureas are frequently used in organocatalysis and typically rely on 3,5‐bis(trifluoromethyl) phenyl moieties motifs to enhance their catalytic activity. In this work, these common motifs were replaced with tailorable functional groups, such as ester or sulfone aryls, applying elemental sulfur in a multicomponent reaction (MCR) strategy for the first time for thiourea catalyst synthesis. First, several thioureas bearing aryl, benzylic or aliphatic moieties were synthesized and tested for their hydrogen bonding strength by evaluating thiourea phosphine oxide complexes via 31P NMR and their catalytic activity in an Ugi four‐component reaction (U‐4CR). Finally, ester and sulfone aryl thioureas were tested in the aminolysis of propylene carbonate, leading to conversions similar to those previously reported in the literature using the 3,5‐bis(trifluoromethyl)phenyl moiety, proving that these groups are suitable alternatives for the trifluoromethyl group.

NEW ROUTE FOR THE SYNTHESES OF SOME NOVEL DERIVATIVES OF 3-ARYL BENZO[d] THIAZOLE-2(3H)-IMINE FROM HIGH SUBSTITUTED THIOUREAS

We have developed herein a new approach to diverse synthesis of novel derivatives of 3-Aryl benzo[d]thiazole-2(3H)-imines (3a-g), by a two-component reaction between diazonium salt (2) and various synthesized N-acyl-N'-aryl thioureas (1a-g), in the presence of sodium tert butoxide as strong base. Finally, it resulted in the production of the desired product with a moderate yield. The chemical structures of these synthesized compounds were confirmed by various physico-chemical methods viz. FT-IR, 1H-NMR, 13C-NMR and elemental analysis.

Understanding the enzymatic inhibition of intestinal alkaline phosphatase by aminophenazone-derived aryl thioureas with aided computational molecular dynamics simulations: synthesis, characterization, SAR and kinetic profiling.

The work presented in this paper aims toward the synthesis of aryl thiourea derivatives 4a-l of pyrazole based nonsteroidal anti-inflammatory drug named 4-aminophenazone, as potential inhibitors of intestinal alkaline phosphatase enzyme. The screening of synthesized target compounds 4a-l for unraveling the anti-inflammatory potential against calf intestinal alkaline phosphatase gives rise to lead member 4c possessing IC50 value 0.420 ± 0.012µM, many folds better than reference standard used (KH2PO4 IC50 = 2.8 ± 0.06µM and L-phenylalanine IC50 = 100 ± 3.1µM). SAR for unfolding the active site binding pocket interaction along with the mode of enzyme inhibition based on kinetic studies is carried out which showed non-competitive binding mode. The enzyme inhibition studies were further supplemented by molecular dynamic simulations for predicting the protein behavior against active inhibitors 4c and 4g during docking analysis. The preliminary toxicity of the synthesized compounds was determined by using brine shrimp assay. This work also includes detailed biochemical analysis along with RO5 parameters for all the newly synthesized drug derivatives 4a-l.

On the Reactivity of Thiourea Derivatives with Silver(I) Oxide

Aryl thioureas of the type ArNHC(S)NR2 react with Ag2O to form the corresponding silver(I) thioureato complexes. Depending on the nature of the thiourea, either insoluble materials, zig‐zag coordination polymers or discrete tetranuclear silver species were isolated and structurally characterised. These thioureato complexes react with one, two or three equivalents of a phosphine ligand, forming a series of compounds with various structural motifs and different coordination numbers at the metal. The spectroscopic properties and structures of several of these compounds are discussed.

Is standardized video gait analysis a valid alternative for instrumented gait analysis in children with Dravet syndrome?

Synthesis of thiobarbituric acids by the reaction of 1,3-disubstituted thioureas and malonic acid in acetyl chloride-acetic acid medium and synthesis of cyclized pyrimidin-7-one by the interaction of 1-(2-hydroxyethyl)-aryl thioureas, with malonic acid in p-tolyl sulphonic acid and acetyl chloride-acetic acid medium at room temperature stirring has been reported. The present protocol is highly eco-friendly alternative to existing methods, reduces the excess use of acetyl chloride and purity of all synthesized molecules checked with the help of reverse phase high performance liquid chromatography with photo diode array (PDA) detection at 254 nm with spectral characterization by 1H, 13C NMR, and MS spectra.

HPLC purification technique: synthesis of unsymmetrical thiobarbituric acids

Synthesis of thiobarbituric acids by the reaction of 1,3-disubstituted thioureas and malonic acid in acetyl chloride-acetic acid medium and synthesis of cyclized pyrimidin-7-one by the interaction of 1-(2-hydroxyethyl)-aryl thioureas, with malonic acid in p-tolyl sulphonic acid and acetyl chloride-acetic acid medium at room temperature stirring has been reported. The present protocol is highly eco-friendly alternative to existing methods, reduces the excess use of acetyl chloride and purity of all synthesized molecules checked with the help of reverse phase high performance liquid chromatography with photo diode array (PDA) detection at 254 nm with spectral characterization by 1H, 13C NMR, and MS spectra.

ONE POT BF3.MeCN CATALYZED SOLVENT FREE SYNTHESIS OF 3,4-DIHYDROPYRIMIDINE-2-ONE ANALOGUES

One-pot solvent free three components coupling of aryl aldehydes, β-dicarbonyl compounds, urea or thiourea was performed to afford corresponding 3,4-dihydropyrimidine-2-ones and their sulfur analogs 3,4-dihydro-pyrimidine-2-thiones. It is the first report of BF 3 .ACN catalyzed the solvent-free synthesis of pyrimidone analogs.

Pyrrolo[1,2-a]azepines Coupled with Benzothiazole and Fluorinated Aryl Thiourea Scaffolds as Promising Antioxidant and Anticancer Agents.

Cancer remains a major health concern throughout history and is responsible for huge numbers of deaths globally. The sensitivity of cancer cells to anticancer drugs is a crucial factor for developing effective treatments. Pyrrolo[1,2-a]azepines coupled with benzothiazole and fluorinated aryl thiourea scaffolds have been synthesized, and their potential as cytotoxic agents was investigated against different cancer cell lines such as human ovarian cancer (SK-OV-3), cervical cancer (HeLa), colon adenocarcinoma (HT-29) and non-small-cell lung carcinoma (A549). Cytotoxicity of new compounds was confirmed using SRB assay against non-cancer MDCK cell line. In addition, free radical scavenging activity of new pyrrolo[1,2-a]azepines was examined by adopting DPPH and ABTS assays. The results concluded that the presence and position of fluorine atom(s) on the thiourea unit played a significant role in order to gain anticipated efficacies. Results of the cytotoxic assay against non-cancer MDCK cells showed that these new derivatives are safe to study further. New structures were confirmed using spectral and elemental analyses. Pyrrolo[1,2-a]azepines endowed with a benzothiazole entity and fluorinated aryl thiourea substituents were derived aiming to furnish remarkable antioxidant and anticancer activities. New molecules generated showed interesting biological result correlated with the structure and substituent of the final derivatives. Specifically, numbers and position of fluorine atoms on the thiourea unit influenced the biological profile of the mentioned compounds.

Copper-Catalyzed and Air-Mediated Mild Cross-Dehydrogenative Coupling of Aryl Thioureas and Dialkyl H-Phosphonates: The Synthesis of Thiophosphonates.

A copper-catalyzed and air-mediated mild cross-dehydrogenative coupling of aryl thioureas and dialkyl H-phosphonates to produce thiophosphonates has been reported. Without addition of base or acid, air as an oxidant, the phosphorylation occurred smoothly to give the target products in moderate to excellent yields at room temperature. The protocol allows the direct formation of a sulfur-phosphorus bond, tolerates a series of functional groups, and shows potential synthetic value for the synthesis of a diversity of thiophosphonates.

K2PdCl4/PPh3-catalyzed Carbon-sulfur Coupling Reaction; An Efficient and One-pot Method to Direct Synthesis of Organic Disulfides/Sulfides from Aryl Halides and Thiourea

K2PdCl4/PPh3-catalyzed Carbon-sulfur Coupling Reaction; An Efficient and One-pot Method to Direct Synthesis of Organic Disulfides/Sulfides from Aryl Halides and Thiourea

Solution-phase microwave assisted parallel synthesis, biological evaluation and in silico docking studies of 2-chlorobenzoyl thioureas derivatives

An efficient and facile microwave-assisted solution phase parallel synthesis for a 38-member library of N-aroyl-N′-aryl thioureas was accomplished successfully. These analogues (1–38) were synthesized under identical set of conditions. It has been observed that the reaction time was drastically reduced from 8 to 12 h for conventional methods to only 10–15 mins. Products obtained were more than 98% pure, as characterized by elemental analysis along with FT-IR and 1H, 13C NMR. The solid-phase structural analysis was accomplished by single crystal XRD analysis. The urease inhibitory potential of synthetic compounds was tested and compounds were found to inhibit urease in moderate to significant manner. Compound 17 was the most potent inhibitor of urease having an IC50 value of 0.17 ± 0.1 μM. To check the cytotoxic profile of the derivatives, lungs cancer cell lines were used. Cytotoxicity analysis revealed remarkable toxicity of the compounds against tested lungs carcinoma and compounds showed variation in inhibition activity due to the substituents attached. The molecular docking studies were carried out to identify the possible binding modes of potent inhibitors in the active site of enzyme. The results suggested that the compounds can be further investigated and used against different cancers.