Synthesis, antimicrobial and anti-inflammatory activities of novel 5-(1-adamantyl)-1,3,4-thiadiazole derivatives

Silver Coordination Polymers Driven by Adamantoid Blocks for Advanced Antiviral and Antibacterial Biomaterials

The development of sustainable biomaterials and surfaces to prevent the accumulation and proliferation of viruses and bacteria is highly demanded in healthcare areas. This study describes the assembly and full characterization of two new bioactive silver(I) coordination polymers (CPs) formulated as [Ag(aca)(μ-PTA)]n·5nH2O (1) and [Ag2(μ-ada)(μ3-PTA)2]n·4nH2O (2). These products were generated by exploiting a heteroleptic approach based on the use of two different adamantoid building blocks, namely 1,3,5-triaza-7-phosphaadamantane (PTA) and 1-adamantanecarboxylic (Haca) or 1,3-adamantanedicarboxylic (H2ada) acids, resulting in the assembly of 1D (1) and 3D (2). Antiviral, antibacterial, and antifungal properties of the obtained compounds were investigated in detail, followed by their incorporation as bioactive dopants (1 wt %) into hybrid biopolymers based on acid-hydrolyzed starch polymer (AHSP). The resulting materials, formulated as 1@AHSP and 2@AHSP, also featured (i) an exceptional antiviral activity against herpes simplex virus type 1 and human adenovirus (HAd-5) and (ii) a remarkable antibacterial activity against Gram-negative bacteria. Docking experiments, interaction with human serum albumin, mass spectrometry, and antioxidation studies provided insights into the mechanism of antimicrobial action. By reporting these new silver CPs driven by adamantoid building blocks and the derived starch-based materials, this study endows a facile approach to access biopolymers and interfaces capable of preventing and reducing the proliferation of a broad spectrum of different microorganisms, including bacteria, fungi, and viruses.

Nascent pharmacological advancement in adamantane derivatives

The adamantane moiety has attracted significant attention since its discovery in 1933 due to its remarkable structural, chemical, and medicinal properties. This molecule has a notable impact in the therapeutic field because of its "add-on" lipophilicity to any pharmacophoric moieties. As in the case of molecular hybridization, in which one pharmacophore is attached to another one(s) with a probability of increasing the biological activity, adding an adamantane unit improves the absorption distribution, metabolism and excretion properties of the resultant hybrid molecule. This review summarizes various reports highlighting the biological activities of adamantane-based synthetic compounds and their structure-activity relationship study. The information presented in this review may open up possible dimensions for adamantane-based drug development and discovery in the pharmaceutical industry after proper structural modifications.

Emerging synthetic strategies and pharmacological insights of 1,3,4-thiadiazole derivatives: a comprehensive review

This review meticulously examines the synthesis techniques for 1,3,4-thiadiazole derivatives, focusing on cyclization, condensation reactions and functional group transformations. It enhances the understanding of these chemical methods that re crucial for tailoring derivative properties and functionalities. This study is considered to be vital for researchers, detailing established effects such as antioxidant, antimicrobial and anticancer activities, and revealing emerging pharmacological potentials such as neuroprotective, antiviral and antidiabetic properties. It also discusses the molecular mechanisms underlying these effects. In addition, this article covers structure-activity relationship studies and computational modelling that are essential for designing potent, selective 1,3,4-thiadiazole compounds. This work lays a foundation for future research and targeted therapeutic development.

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.

1,3,4-Thiadiazole and 1,2,4-triazole-5-thione derivatives bearing 2-pentyl-5-phenyl-2,4-dihydro-3H-1,2,4-triazole-3-one ring: Synthesis, molecular docking, urease inhibition, and crystal structure

Two series of 1,3,4-thiadiazole (40a-o) and 1,2,4-triazole-5-thione (41a-l) derivatives bearing a 2-pentyl-5-phenyl-1,2,4-triazole-3-one ring were synthesized and then studied for their urease inhibitory activities using thiourea as a standard drug. Among the two groups, the first group (40a-o) did not show good activity while the second group (41a-l) showed excellent activity. Compound 41j (1091.24 ± 14.02 µM) of the second series of compounds showed lower activity than thiourea, while the remaining 11 compounds (41a-i, k, and l) showed better activity than thiourea (183.92 ± 13.14 µM). Among the 11 compounds, 41b (15.96 ± 2.28 µM) having the 3-F group on the phenyl ring showed the highest inhibitory activity. Urease kinetic studies of 41b, which is the most active compound, determined it to have an un-competitive inhibition potential. Moreover, in silico analysis against urease from jack bean with 27 new heterocyclic compounds and the reference molecule was carried out to see the necessary interactions responsible for urease activity. The docking calculations of all compounds supported stronger binding to the receptor than the reference molecule, with high inhibition constants. In addition, compound 40m was characterized by single-crystal X-ray diffraction analysis. X-ray analysis reveals that the structures of the compound 40m crystallize in the monoclinic P21/c space group with the cell parameters: a = 10.2155(9) Å, b = 22.1709(18) Å, c = 21.4858(17) Å, β = 99.677(8)°, V = 4797.0(7) ų . X-ray diffraction analyses were also performed to gain insights into the role of weak intermolecular interactions and C-H…X (halogen) interactions in compound 40m that influence the crystal packing.

Synthesis and characterization of new 1,3,4-thiadiazole derivatives: study of their antibacterial activity and CT-DNA binding

1,3,4-Thiadiazole molecules (1-4) were synthesized by the reaction of phenylthiosemicarbazide and methoxy cinnamic acid molecules in the presence of phosphorus oxychloride, and characterized with UV, FT-IR, ¹³C-NMR, and ¹H-NMR methods. DFT calculations (b3lyp/6-311++G(d,p)) were performed to investigate the structures' geometry and physiochemical properties. Their antibacterial activity was screened for various bacteria strains such as Enterobacter aerogenes, Escherichia coli ATCC 13048, Salmonella kentucky, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus and Gram positive such as Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 7644, Enterococcus faecium, Enterococcus durans, Staphylococcus aureus ATCC, Serratia marcescens, Staphylococcus hominis, Staphylococcus epidermidis, alfa Streptococcus haemolyticus, Enterococcus faecium and found to have an inhibitory effect on Klebsiella pneumoniae and Staphylococcus hominis, while molecules 1, 3 and 4 had an inhibitory effect on Staphylococcus epidermidis and alpha Streptococcus haemolyticus. The experimental results were supported by the docking study using the Kinase ThiM from Klebsiella pneumoniae. All the investigated compounds showed an inhibitory effect for the Staphylococcus epidermidis protein. In addition, the mechanism of the 1-4 molecule interaction with calf thymus-DNA (CT-DNA) was investigated by UV-vis spectroscopic methods.

Structural and Energetic Properties of Weak Noncovalent Interactions in Two Closely Related 3,6-Disubstituted-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole Derivatives: In Vitro Cyclooxygenase Activity, Crystallography, and Computational Investigations

Two 3,6-disubstituted-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives, namely, 3-(adamantan-1-yl)-6-(2-chloro-6-fluorophenyl)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole 1 and 6-(2-chloro-6-fluorophenyl)-3-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole 2, were prepared, and the detailed analysis of the weak intermolecular interactions responsible for the supramolecular self-assembly was performed using X-ray diffraction and theoretical tools. Analyses of Hirshfeld surface and 2D fingerprint plot demonstrated the effect of adamant-1-yl/phenyl moieties on intermolecular interactions in solid-state structures. The effect of these substituents on H···H/Cl/N contacts was more specific. The CLP-PIXEL and density functional theory methods provide information on the energetics of molecular dimers observed in these compounds. The crystal structure of compound 1 stabilizes with a variety of weak intermolecular interactions, including C–H···N, C–H···π, and C–H···Cl hydrogen bonds, a directional C–S···π chalcogen bond, and unconventional short F···C/N contacts. The crystal structure of compound 2 is stabilized by π-stacking interactions, C–H···N, C–H···π, and C–H···Cl hydrogen bonds, and highly directional attractive σ–hole interactions such as the C–Cl···N halogen bond and the C–S···N chalcogen bond. In addition, S(lp)···C(π) and short N···N contacts play a supportive role in the stabilization of certain molecular dimers. The final supramolecular architectures resulting from the combination of different intermolecular interactions are observed in both the crystal packing. The molecular electrostatic potential map reveals complementary electrostatic potentials of the interacting atoms. The quantum theory of atoms in molecules approach was used to delineate the nature and strength of different intermolecular interactions present in different dimers of compounds 1 and 2. The in vitro experiments suggest that both compounds showed selectivity against COX-2 targets rather than COX-1. Molecular docking analysis showed the binding pose of the compounds at the active sites of COX-1/2 enzymes.

Synthesis and Antimicrobial Activity Screening of Piperazines Bearing N,N'-Bis(1,3,4-thiadiazole) Moiety as Probable Enoyl-ACP Reductase Inhibitors

A new N,N'-disubstituted piperazine conjugated with 1,3,4-thiadiazole and 1,2,4-triazole was prepared and the chemical structures were identified by IR, NMR and elemental analysis. All the prepared compounds were tested for their antimicrobial activity. The antimicrobial results indicated that the tested compounds showed significant antibacterial activity against gram-negative strains, especially E. coli, relative to gram-positive bacteria. Docking analysis was performed to support the biological results; binding modes with the active site of enoyl reductase amino acids from E. coli showed very good scores, ranging from -6.1090 to -9.6184 kcal/mol. Correlation analysis was performed for the inhibition zone (nm) and the docking score.

Exploring the Antiparasitic Activity of Tris-1,3,4-Thiadiazoles against Toxoplasma gondii-Infected Mice

Nitrogen-containing atoms in their core structures have been exclusive building blocks in drug discovery and development. One of the most significant and well-known heterocycles is the 1,3,4-thidiazole nucleus, which is found in a wide range of natural products and therapeutic agents. In the present work, certain tris-1,3,4-thiadiazole derivatives (6, 7) were synthesized through a multi-step synthesis approach. All synthesized compounds were characterized using different spectroscopic tools. Previously, thiadiazole compounds as anti-Toxoplasma gondii agents have been conducted and reported in vitro. However, this is the first study to test the anti-Toxoplasma gondii activity of manufactured molecular hybrids thiadiazole in an infected mouse model with the acute RH strain of T. gondii. All the observed results demonstrated compound (7)’s powerful activity, with a considerable reduction in the parasite count reaching 82.6% in brain tissues, followed by liver and spleen tissues (65.35 and 64.81%, respectively). Inflammatory and anti-inflammatory cytokines assessments proved that Compound 7 possesses potent antiparasitic effect. Furthermore, docking tests against TgCDPK1 and ROP18 kinase (two major enzymes involved in parasite invasion and egression) demonstrated compound 7’s higher potency compared to compound 6 and megazol. According to the mentioned results, tris-1,3,4-thiadiazole derivatives under test can be employed as potent antiparasitic agents against the acute RH strain of T. gondii.

Azo dyes containing 1,3,4-thiadiazole fragment: synthesis and properties

New 1,3,4-thiadiazole derivatives containing a diazenyl group, as well as simultaneously a diazenyl and an imino group were synthesized.

Exploring of antioxidant and antibacterial properties of novel 1,3,4-thiadiazole derivatives: Facile synthesis, structural elucidation and DFT approach to antioxidant characteristics

In recent years, compounds containing thiophene and 1,3,4-thiadiazole skeletons have become important cyclic compounds, especially in medicinal chemistry. In this manner, we synthesized and isolated seven 1,3,4-thiadiazole derivatives with thiophene groups and fully characterized by elemental analysis and general spectroscopic methods such as ¹H NMR, ¹³C NMR, and FT-IR. Antibacterial activities of the title compounds were investigated by using TLC-Dot blot, macro dilution, well diffusion, and growth curve analysis methods. Compounds 1 and 6 showed inhibitory activities against all tested gram-negative and gram-positive bacteria. TLC-DPPH and DPPH assays, on the other hand, were performed to detect the antioxidant activities of the 1,3,4-thiadiazole derivatives and compound 1 exhibited the highest antioxidant activity at all tested concentrations. QTAIM and NCI calculations were performed as well as structural, electronic, and spectral analyzes using density functional theory (DFT). Calculations were carried out at the B3lyp/6-311 + +g(2d,2p) level of theory, and the data were used to examine the antioxidant activity of the compounds.

Quantification of a New Antifungal Drug Based on 1,3,4-Thiadiazole by HPLC-ESI/MS: Method Development, Validation and Pharmacokinetic Application

The high sensitive HPLC-ESI/MS method for quantitative determination of a new antifungal drug - 2-[(1Z)-1-(3,5-diphenyl-1,3,4-thiadiazol-2(3Н)-ylidene)methyl]-3,5-diphenyl-1,3,4-thiadiazol-3-ium chloride (TDZ) - was developed and fully validated. TDZ was separated from plasma and urine samples by acetonitrile deproteinization and extraction without time-consuming sample preparation. The reversed-phase high-performance liquid chromatography on Kromasil 100-3.5 C8 column of TDZ in isocratic elution mode using 0.03% trifluoroacetic acid : acetonitrile (65:35, v/v) at a flow rate of 0.2 mL min^-1 was performed. Determination of TDZ was carried out by a positive electrospray ionization in a selected ion monitoring mode for [M⁺]=489 m/z. The method of absolute calibration was used for quantification of TDZ in two concentrations ranges: 100-2500 pg mL^-1 and 2500-30 000 pg mL^-1. The established method showed a good linearity (R=0.999 for both ranges), the limits of determination and quantification were 50 and 100 pg mL^-1, respectively. The Intra- and Inter-day precision values were measured by t-Distribution and Fisher's Exact Test and were in accordance with the regulatory guidance. Low matrix effects and good recovery were found for TDZ. The present method was successfully applied to determine the pharmacokinetic parameters of TDZ by means of intravenous and oral administrations to rats at 5.0 mg kg^-1 and 10.0 mg kg^-1, respectively.

A Compendium of the Most Promising Synthesized Organic Compounds against Several Fusarium oxysporum Species: Synthesis, Antifungal Activity, and Perspectives

Vascular wilt caused by F. oxysporum (FOX) is one of the main limitations of producing several agricultural products worldwide, causing economic losses between 40% and 100%. Various methods have been developed to control this phytopathogen, such as the cultural, biological, and chemical controls, the latter being the most widely used in the agricultural sector. The treatment of this fungus through systemic fungicides, although practical, brings problems because the agrochemical agents used have shown mutagenic effects on the fungus, increasing the pathogen's resistance. The design and the synthesis of novel synthetic antifungal agents used against FOX have been broadly studied in recent years. This review article presents a compendium of the synthetic methodologies during the last ten years as promissory, which can be used to afford novel and potential agrochemical agents. The revision is addressed from the structural core of the most active synthetic compounds against FOX. The synthetic methodologies implemented strategies based on cyclo condensation reactions, radical cyclization, electrocyclic closures, and carbon-carbon couplings by metal-organic catalysis. This revision contributes significantly to the organic chemistry, supplying novel alternatives for the use of more effective agrochemical agents against F. oxysporum.

Development of adamantane scaffold containing 1,3,4-thiadiazole derivatives: Design, synthesis, anti-proliferative activity and molecular docking study targeting EGFR

A new series of 1,3,4-thiadiazolo-adamantane derivatives were synthesized through molecular hybridization approach, then used as starting material to synthesize chloro and cyano acetamide-thiadiazole derivatives 2, 3. The newly designed compounds 1-3 were treated with different reagents to design 5-adamantyl thiadiazole derivatives 4-17 and evaluate their in vitro anti-proliferative activity against three cancer cell lines (MCF-7, HepG-2 and A549). Doxorubicin was used as a positive control. The most promising compounds 5, 6, 10a, 10b, 14b, 14c, and 17 showed up-regulation for BAX and down-regulation of Bcl-2, these findings proved their role as hopeful apoptotic inducers. In addition, the inhibitory activity against both wild EGFR^WT and mutant EGFR^L858R-TK for these derivatives revealed that compounds 5, 14c, and 17 have IC₅₀ value ranging from 85 nM to 71.5 nM against wild EGFR^WT and 37.85-41.19 nM against the mutant type, Lapatinib was used as a reference standard with IC₅₀ values of 31.8 nM and 39.53 nM, respectively. The most potent derivatives were subjected to further evaluation against double mutant EGFR ^L858R/T790M and showed good IC₅₀ values between (0.27-0.78 nM) compared to Lapatinib (0.18 nM) and Erlotinib (0.21 nM). Among them, thiazolo-thiadiazole adamantane derivative 17 exhibited the strongest inhibitory activity to the EGFR. Molecular docking studies were performed inside the active site of EGFR (1M17), and binding energy scores ranged between (-19.19 to -22.07 Kcal/mol) compared to Erlotinib (-19.10 Kcal/mol). Furthermore, oral bioavailability beside some pharmacokinetics properties of these derivatives were also investigated in this research work.

Synthesis of indole-based-thiadiazole derivatives as a potent inhibitor of α-glucosidase enzyme along with in silico study

A series of nineteen (1-19) indole-based-thiadiazole derivatives were synthesized, characterized by ¹HNMR, ¹³C NMR, MS, and screened for α-glucosidase inhibition. All analogs showed varied α-glucosidase inhibitory potential with IC₅₀ value ranged between 0.95 ± 0.05 to 13.60 ± 0.30 µM, when compared with the standard acarbose (IC₅₀ = 1.70 ± 0.10). Analogs 17, 2, 1, 9, 7, 3, 15, 10, 16, and 14 with IC₅₀ values 0.95 ± 0.05, 1.10 ± 0.10, 1.30 ± 0.10, 1.60 ± 0.10, 2.30 ± 0.10, 2.30 ± 0.10, 2.80 ± 0.10, 4.10 ± 0.20 and 4.80 ± 0.20 µM respectively showed highest α-glucosidase inhibition. All other analogs also exhibit excellent inhibitory potential. Structure activity relationships have been established for all compounds primarily based on substitution pattern on the phenyl ring. Through molecular docking study, binding interactions of the most active compounds were confirmed. We further studied the kinetics study of analogs 1, 2, 9 and 17 and found that they are Non-competitive inhibitors.

QSAR and molecular docking studies of novel 2,5-distributed-1,3,4-thiadiazole derivatives containing 5-phenyl-2-furan as fungicides against Phythophthora infestans

Background

The 1,3,4-thiadiazoles are among the structural moieties that were found to be of utmost importance in the fields of pharmacy and agrochemicals because of their widespread biological activity that includes anti-tumor, antibacterial, anti-inflammatory, antihypertensive, anti-tuberculosis, anticonvulsant, and antimicrobial, among others.

Results

QSAR and molecular docking studies were carried out on thirty-two (32) derivatives of 2,5-disubstituted-1,3,4-thiadiazoles for their antifungal activities toward Phytophthora infestans. Using the “graphical user interface” of Spartan14 software, the structure of the compounds of the dataset is drawn and then optimized at DFT/B3LYP/6-31G* quantum mechanical method of the software. Molecular descriptors of the optimized compounds were calculated and later on divided into the training set and test sets (at a ratio of 3:1). The training set was used for model generation and the test set was for external validation of the generated model. Four models were generated by the employment of genetic function approximation (GFA) in which the optimal model (4) turned out to have the following statistical parameters: R2 = 0.798318, R2adj = 0.750864, cross-validation R2(Q2cv) = 0.662654, and external validation R2pred = 0.624008. On the molecular docking study of thiadiazole compounds with the target protein of Phytophthora infestans effector site (PDB ID: 2NAR ), compound 13 shows the highest binding affinity with − 9.3 kcal/mol docking score and composes hydrophobic as well as H-bond interactions with the target protein (2NAR).

Conclusion

The result of the QSAR study signifies the stability and robustness of the built model by considering the validation parameters and this gave an idea of template/ligand-based design while the molecular docking study revealed the binding interaction between the ligand and the protein site which gave an insight toward an “optimization method” of the structure-based design for the discovery of more potent compounds with better activity against Phytophthora infestans using the approach of computer-aided drug design (CADD) in plant pathology.

X-ray and theoretical investigation of (Z)-3-(adamantan-1-yl)-1-(phenyl or 3-chlorophenyl)-S-(4-bromobenzyl)isothioureas: an exploration involving weak non-covalent interactions, chemotherapeutic activities and QM/MM binding energy

A detailed exploration of crystal packing of two adamantane-isothiourea hybrid derivatives along with a known closely related structure has been performed to delineate the effect of halogen substituents and the role of weak intermolecular interactions in their supramolecular architectures. The adamantane-isothiourea hybrid derivatives used in the present study are (Z)-3-(Adamantan-1-yl)-S-(4-bromobenzyl)-1-phenylisothiourea (1), C₂₄H₂₇BrN₂S and (Z)-3-(Adamantan-1-yl)-S-(4-bromobenzyl)-1-(3-chlorophenyl)isothiourea (2), C₂₄H₂₆BrClN₂S, characterized by X-ray crystallography. The X-ray structures revealed that the molecular conformation of 1 and 2 are different and stabilized by intramolecular C-H···N interactions. In addition, a short intramolecular H···H contact is formed in 2. The Hirshfeld surface analysis was used to delineate the nature of different intermolecular interactions and their contributions toward crystal packing. The quantitative analysis of strengths of molecular dimers existed in 1 and 2 has been performed using the PIXEL method. The electrostatic potential map clearly revealed nature and strength of σ-holes at Br and Cl atoms. The topological analysis was used to characterize the nature and the strength of various intermolecular interactions including the type I Br···Br contact. Interestingly, all the H-H bonding observed in 1 and 2 show closed-shell in nature. Further, an in-vitro antimicrobial activity studies suggest that the title compounds exhibited potent antibacterial activity against all the tested Gram-positive bacterial strains and Gram-negative Escherichia coli. Compound 2 showed marked anti-proliferative activity against MCF-7 and HeLa cell lines.Communicated by Ramaswamy H. Sarma.

Synthesis, characterization and electrochemical properties of some biologically important indole-based-sulfonamide derivatives

A new series of indole-based-sulfonamide derivatives (A1–A8) was synthesized by treating 5-fluoro-1H-indole-3-carbohydrazide with different aryl-sulfonyl chloride in the presence of pyridine. All synthesized derivatives (A1–A8) were characterized by different analytical methods. The electrochemical behavior of these compounds (A1–A8) was investigated in detail using cyclic voltammetry (CV) and square wave voltammetry (SWV) at the pencil graphite electrode (PGE). In the present study, the redox behavior of all derivatives varies due to the nature of substitutions in the indole sulfonamide moiety. Various fundamental electrochemical parameters, including the standard heterogeneous rate constants (k_s), and the electroactive surface coverage (Г) were calculated from the obtained CVs. The obtained results shed light on the understanding of structure–activity relationships of this class of compounds.

Synthesis, Characterization and Biological Evaluation of Metal Adamantyl 2-Pyridylhydrazone Complexes

Four new complexes derived from adamantly containing hydrazone (APH) ligand with Cu(II) (1), Co(II) (2), Ni(II) (3) and Zn(II) (4), have been synthesized and characterized using different physicochemical methods. The structure of the ligand APH and its copper complex 1 have been established by single-crystal X-ray diffraction direct methods, which reveal that complex 1 has distorted square-pyramidal geometry. Complexes 1–4 are screened against seven human cancer cell lines namely, breast cancer cell lines (MCF7, T47D, MDA-MB-231), prostate cancer cell lines (PC3, DU145) and the colorectal cancer cell line Coco-2, for their antiproliferative activities. Complex 1 has shown a promising anticancer activity compared to the other ones. The structural and spectroscopic analysis of APH and its complexes are confirmed by DFT calculations.

New aryl Schiff bases of thiadiazole derivative of ibuprofen as DNA binders and potential anticancer drug candidates

The work presented in this paper describes the synthesis of two new aryl Schiff bases [(E)-N-(4-(benzyloxy)-3-methoxybenzylidene)-5-(1-(4-isobutylphenyl)ethyl)-1,3,4-thiadiazol-2-amine] (ASB-1) and [(E)-N-(4-(benzyloxy)benzylidene)-5-(1-(4-isobutylphenyl)ethyl)-1,3,4-thiadiazol-2-amine] (ASB-2). These compounds were characterized by different analytical techniques and then studied for DNA binding. Binding studies were carried out at neutral pH (7.0) and at 37 °C by theoretical and experimental methods including DFT, molecular docking, spectroscopy (UV-visible, fluorescence), cyclic voltammetry (CV) and viscometry. Further investigations of these compounds were done on hepatocellular carcinoma; Huh-7 cancer cell line. Binding constant, free energy change and binding site size, i.e. K_b, ΔG and n were evaluated which indicated that both ASB-1 and ASB-2 bind significantly and spontaneously with the DNA. However, data revealed relatively greater binding of ASB-1 with DNA. Spectral and voltammetric results were found supportive of each other. Binding site sizes and viscosity measurements verified the mixed binding mode of interactions as observed in molecular docking analysis, i.e. intercalation with groove binding. DNA binding studies were very well correlated with the in-vitro studies performed on Huh-7 cell line as well as normal HEK-293 cell lines. The compound ASB-1 not only showed greater binding affinity toward DNA but also showed greater anticancer potency with least IC₅₀ value as compared to ASB-2.

Quantitative assessment of the nature of noncovalent interactions in N-substituted-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amines: insights from crystallographic and QTAIM analysis

Three adamantane-1,3,4-thiadiazole hybrid derivatives namely; N-ethyl-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amine I, N-(4-fluorophenyl)-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amine II and (4-bromophenyl)-5-(adamantan-1-yl)-N-1,3,4-thiadiazole-2-amine III, have been synthesized and crystal structures have been determined at low temperature. The structures revealed that the orientation of the amino group is different in non-halogenated structures. Intra- and intermolecular interactions were characterized on the basis of the quantum theory of atoms-in-molecules (QTAIM) approach. Intermolecular interaction energies for different molecular pairs have been obtained using the PIXEL method. Hirshfeld surface analysis and 2D-fingerprint plots revealed that the relative contributions of different non-covalent interactions are comparable in compounds with halogen (Br and F) substitutions. Crystal structures of II and III show isostructural behaviour with 1D supramolecular constructs. In all three structures, the N-H⋯N hydrogen bond was found to be stronger among other noncovalent interactions. The H-H bonding showed a closed shell in nature and played significant roles in the stabilization of these crystal structures.

Synthesis and crystal structure of 3-(adamantan-1-yl)-4-(2-bromo-4-fluoro-phen-yl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C18H19BrFN3S, the 1,2,4-triazole ring is nearly planar with a maximum deviation of -0.009 (3) and 0.009 (4) Å, respectively, for the S-bound C atom and the N atom bonded to the bromo-fluoro-phenyl ring. The phenyl and triazole rings are almost perpendicular to each other, forming a dihedral angle of 89.5 (2)°. In the crystal, the mol-ecules are linked by weak C-H⋯π(phen-yl) inter-actions, forming supra-molecular chains extending along the c-axis direction. The crystal packing is further consolidated by inter-molecular N-H⋯S hydrogen bonds and by weak C-H⋯S inter-actions, yielding double chains propagating along the a-axis direction. The crystal studied was refined as a racemic twin.

Synthesis and Bioactivity of Hydrazide-Hydrazones with the 1-Adamantyl-Carbonyl Moiety

Reaction of 1-adamantyl carbohydrazide (1) with various substituted benzaldehydes and acetophenones yielded the corresponding hydrazide-hydrazones with a 1-adamantane carbonyl moiety. The new synthesized compounds were tested for activities against some Gram-negative and Gram-positive bacteria, and the fungus Candida albicans. Compounds 4a, 4b, 5a, and 5c displayed potential antibacterial activity against tested Gram-positive bacteria and C. albicans, while compounds 4e and 5e possessed cytotoxicity against tested human cancer cell lines.

Crystal structure of tetra-μ-acetato-bis-[(5-amino-2-methyl-sulfanyl-1,3,4-thia-diazole-κN 1)copper(II)]

The reaction of 2-methyl-thio-5-amino-1,3,4-thia-diazole (Me-SNTD; C3H5N3S2) with copper(II) acetate monohydrate [Cu(OAc)2·H2O; C4H8CuO5] resulted in the formation of the title binuclear compound, [Cu2(C2H3O2)4(C3H5N3S2)2] or [Cu2(OAc)4(Me-SNTD)2]. The structure has triclinic (P ) symmetry with a crystallographic inversion centre located at the midpoint of the line connecting the Cu atoms in the dimer. These two Cu atoms of the dimer [Cu⋯Cu = 2.6727 (6) Å] are held together by four carboxyl-ate groups. Each Cu atom is further coordinated to the N atom of an Me-SNTD mol-ecule and exhibits a Jahn-Teller-distorted octa-hedral geometry. The dimers are connected into infinite chains by hydrogen bonds between the NH (Me-SNTD) and the carboxyl-ate groups of neighbouring mol-ecules, generating an R 2 2(12) ring motif. The mol-ecules are further linked by C-H⋯π inter-actions between the thia-diazole rings and the methyl groups of the acetate units.

Crystal structures and Hirshfeld surface analysis of 2-(adamantan-1-yl)-5-(4-fluoro-phen-yl)-1,3,4-oxa-diazole and 2-(adamantan-1-yl)-5-(4-chloro-phen-yl)-1,3,4-oxa-diazole

The crystal structures of the title adamantane-oxa-diazole hybrid compounds, C18H19FN2O (I) and C18H19ClN2O (II), are built up from an adamantane unit and a halogenophenyl ring, [X = F (I), Cl (II)], in position 5 on the central 1,3,4-oxa-diazole unit. The mol-ecular structures are very similar, only the relative orientation of the halogenophenyl ring in comparison with the central five-membered ring differs slightly. In the crystals of both compounds, mol-ecules are linked by pairs of C-H⋯N hydrogen bonds, forming inversion dimers with R 2 2(12) ring motifs. In (I) the dimers are connected by C-H⋯F inter-actions, forming slabs lying parallel to the bc plane. In (II), the dimers are linked by C-H⋯π and offset π-π inter-actions [inter-planar distance = 3.4039 (9) Å], forming layers parallel to (10).