Synthesis and antimicrobial studies of some novel bis-[1,3,4]thiadiazole and bis-thiazole pendant to thieno[2,3-b]thiophene moiety

Novel hybrid thiazoles, bis-thiazoles linked to azo-sulfamethoxazole: Synthesis, docking, and antimicrobial activity

The reaction of sulfamethoxazolehydrazonoyl chloride with thiosemicarbazones, bis-thiosemicarbazones, or 4-amino-3-mercapto-1,2,4-triazole in dioxane in the presence of triethylamine as a basic catalyst at reflux resulted in the regioselective synthesis of thiazoles and bis-thiazoles linked to azo-sulfamethoxazole as novel hybrid molecules. The structures of the new compounds were confirmed using a range of spectra. Each compound's antibacterial properties were evaluated using the agar well-diffusion technique, and most of them demonstrated significant potency. In silico investigations revealed that the described compounds had strong interactions with the binding sites of MurE ligase, tyrosyl-tRNA synthetase, and dihydropteroate synthase, demonstrating inhibitory activity.

Novel Scaffolds Based on Bis-thiazole Connected to Quinoxaline or Thienothiophene through 2-Phenoxy-N-arylacetamide Groups as New Hybrid Molecules: Synthesis, Antibacterial Activity, and Molecular Docking Investigations

The resistance of microorganisms to antimicrobials has endangered the health of many people across the world. Overcoming the resistance problem will require the invention of molecules with a new mechanism of action so that no cross-resistance with existing therapies occurs. Because of their powerful antibacterial activity against a wide spectrum of Gram-positive and Gram-negative bacterial strains, heterocyclic compounds are appealing candidates for medicinal chemists. In this regard, as unique hybrid compounds, we synthesized a novel family of bis-thiazoles linked to quinoxaline or thienothiophene via the 2-phenoxy-N-arylacetamide moiety. The target compounds were synthesized by reacting the relevant bis(α-haloketones) with the corresponding thiosemicarbazones in EtOH at reflux with a few drops of TEA. Under comparable reaction conditions, the isomeric bis(thiazoles) were synthesized by reacting the appropriate bis(thiosemicarbazone) with the respective α-haloketones. The structures of the novel compounds were confirmed using elements and spectral data. All of the synthesized compounds were tested for antibacterial activity in vitro. With an inhibitory zone width of 12 mm, compound 12a had the same activity as the reference medication tobramycin against Staphylococcus aureus. Compound 12b showed 20 mg/mL as a minimum inhibitory concentration (MIC) against Bacillus subtilis. Some of the synthesized compounds were tested via molecular docking against two bacterial proteins (dihydrofolate reductase and tyrosyl-tRNA synthetase).

Synthesis, X-ray structure, antimicrobial activity, DFT and molecular docking studies of N-(thiophen-2-ylmethyl)thiophene-2-carboxamide

In the present study, N-(thiophen-2-ylmethyl)thiophene-2-carboxamide, C10H9NOS2, (I), was obtained by the reaction of thiophene-2-carbonyl chloride and thiophen-2-ylmethanamine. Characterization of (I) was carried out using X-ray diffraction, spectroscopic techniques and elemental analyses. The DFT/B3LYP/6-311++G(d,p) theoretical level was successfully applied to calculate the optimized geometry and the local and global chemical activity parameters. The results obtained show good agreement between the experimental and theoretical geometrical parameters. The local and global chemical activity parameters were examined to determine the electrophilic and nucleophilic sites in (I). The natural bond orbital (NBO) analysis of (I) gives an efficient methodology for investigating the inter- and intramolecular bonding, as well as giving a convenient basis for investigating charge transfer or conjugative interactions in molecular systems. Also, the antimicrobial activity of (I) was investigated against eight microorganisms using the microdilution method and it is found to have an effective antibacterial activity. In addition, molecular docking studies were calculated in order to understand the nature of the binding of (I) with a lung cancer protein (PDB entry 1x2j).

Synthesis and in vitro antitumor evaluation of some new thiophenes and thieno[2,3-d]pyrimidine derivatives

New thiophene (2-13) and thienopyrimidine (15-27) derivatives have been synthesized. Twenty three compounds were screened against five cell lines namely; hepatocellular carcinoma (liver) HepG-2, epidermoid carcinoma (larynx) Hep-2, mammary gland (breast) MCF-7, human prostate cancer PC-3 and epithelioid cervix carcinoma HeLa. The results revealed that compounds 15,16,17,24 and 25 showed the highest antitumor activity against all tested cell lines compared to Doxorubicin. In order to explain the expected mode of action of the observed anticancer activity, compounds 15,16,17,24 and 25 were selected to screen their DNA binding affinity and enzyme inhibitory activity against DNA polymerase, thymidylate synthase and tyrosine kinase. The results revealed that the tested compounds showed good DNA binding affinity as well as good inhibitory activity against the three enzymes which might explain the observed anticancer activity of the target compounds.

A facile synthesis and anticancer activity of some novel thiazoles carrying 1,3,4-thiadiazole moiety

Background

Thiazoles and 1,3,4-thiadiazoles have been reported to possess various pharmacological activities.

Results

A novel series of thiazoles carrying 1,3,4-thiadiazole core were designed and prepared via the reaction of the 2-(4-methyl-2-phenylthiazole-5-carbonyl)-N-phenylhydrazinecarbo-thioamide with the appropriate hydrazonoyl chlorides. The structures of the newly synthesized compounds were confirmed based on elemental and spectral analysis as well as their alternative syntheses. The cytotoxic potency of the newly synthesized thiadiazoles was evaluated by their growth inhibitory potency in liver HepG2 cancer cell line. Also, the structure activity relationship was studied.

Conclusions

All the newly synthesized compounds were evaluated for their anticancer activity against liver carcinoma cell line (HepG2) using MTT assay. The results revealed that the compounds 12d, 12c, 6g, 18b, 6c, and 6f (IC50 = 0.82, 0.91, 1.06, 1.25, 1.29 and 1.88 µM, respectively) had good antitumor activity against liver carcinoma cell line (HepG2) when compared with the standard drug Doxorubicin (IC₅₀ = 0.72 µM).Graphical abstract

Synthesis and Structure-Activity Relationship of Some New Thiophene-Based Heterocycles as Potential Antimicrobial Agents

Several new pyrazole, pyridine, [1,2,4]triazolo[1,5-α]pyrimidine, benzimidazo[1,2-a]pyrimidine and 1,2,4-triazolo[3,4-c][1,2,4]triazine derivatives incorporating a thiophene moiety were synthesized from (E)-ethyl 5-(3-(dimethylamino)acryloyl)-4-phenyl-2-(phenylamino)thiophene-3-carboxylate (1). The structures of the newly synthesized compounds were confirmed by IR, ¹H-, ¹³C-NMR, mass spectral data and elemental analysis. The antibacterial and antifungal activities of all the synthesized compounds were evaluated. The results indicated that compounds 9, 12, and 19 were found to be more potent than the standard drug Amphotericin B against Aspergillus fumigates. Additionally, compound 12 exhibited higher activity than the standard drug Amphotericin B against Syncephalastrum racemosum.

Hydrazonoyl Chlorides as Precursors for Synthesis of Novel Bis-Pyrrole Derivatives

A convenient synthesis of some novel bis-pyrrole derivatives via hydrazonoyl halides is described. Antimicrobial evaluation of some selected examples of the synthesized products was carried out. The bis-pyrrole derivative having chloro substituents showed good activity against all of the used microbes. The molecular docking of the bis-pyrrole derivatives was performed by the Molecular Operating Environment (MOE) program.

Selective C-arylation of 2,5-dibromo-3-hexylthiophene via Suzuki cross coupling reaction and their pharmacological aspects

The present study reports the synthesis of various new derivatives based on 5-aryl-2-bromo-3-hexylthiophene with moderate-to-good yields via a palladium-catalyzed Suzuki cross-coupling reaction. This coupling method involved the reaction of 2,5-dibromo-3-hexylthiophene with several arylboronic acids in order to synthesize corresponding thiophene derivatives under controlled and optimal reaction conditions. The different substituents (CH₃, OCH₃, Cl, F etc.) present on arylboronic acids are found to have significant electronic effects on the overall properties of new products. The synthesized thiophene molecules were studied for their haemolytic, biofilm inhibition and anti-thrombolytic activities, and almost all products showed potentially good properties. The compound 2-bromo-5-(3-chloro-4-fluorophenyl)-3-hexylthiophenein particular exhibited the highest values for haemolytic and bio-film inhibition activities among all newly synthesized derivatives. In addition, the compound 2-bromo-3-hexyl-5-(4-iodophenyl)thiophene also showed high anti-thrombolytic activity, suggesting the potential medicinal applications of these newly synthesized compounds.

Microwave assistant synthesis, antifungal activity and DFT theoretical study of some novel 1,2,4-triazole derivatives containing pyridine moiety

In order to investigate the biological activity of novel 1,2,4-triazole compounds, seventeen novel 1,2,4-triazole derivatives containing pyridine moiety were synthesized under microwave assistant condition by multi-step reactions. The structures were characterized by ¹H NMR, MS and elemental analyses. The target compounds were evaluated for their fungicidal activities against Stemphylium lycopersici (Enjoji) Yamamoto, Fusarium oxysporum. sp. cucumebrium, and Botrytis cinerea in vivo, and the results indicated that some of the title compounds displayed excellent fungicidal activities. Theoretical calculation of the title compound was carried out with B3LYP/6-31G (d,p). The full geometry optimization was carried out using 6-31G (d,p) basis set, and the frontier orbital energy, atomic net charges were discussed, and the structure-activity relationship was also studied.

Efficient synthesis of Some Novel Symmetrical and Unsymmetrical Pyridine bis-1,2,4-triazoles and bis-1,3,4-thiadiazoles

A series of novel bis-1,2,4-triazoles and bis-1,3,4-thiadiazoles bearing pyridine rings was synthesised, by multistep reaction sequences, in good to high yields. Reaction of pyridine-2,5-bis- and pyridine-2,6-bis-carbohydrazides with alkyl- or aryl-isothiocyanates gave the corresponding bis(thiosemicarbazide) derivatives, which could be cyclised under strongly basic conditions to give novel pyridine bis(1,2,4-triazole-3-thiols). However, under strongly acidic conditions the corresponding bis(2-amino-1,3,4-thiadiazoles) were obtained. The synthetic routes and spectroscopic characterisation of the new compounds are reported.

Regioselective Synthesis of Some Pyrazole Scaffolds Attached to Benzothiazole and Benzimidazole Moieties

Condensation of 2-(benzothiazol-2-yl)acetonitrile (1) or 2-(1-methyl-1H-benzimidazol-2-yl)acetonitrile (2) with thiophene-2-carbaldehyde afforded the corresponding acrylonitrile derivatives3or4, respectively. The 1,3-dipolar cycloaddition reaction of the acrylonitrile3or4with nitrile-imine6gave novel pyrazole derivatives pendant to benzothiazole and benzimidazole. The pyrazoline derivative7was converted into the corresponding pyrazole derivative11via thermal elimination of hydrogen cyanide upon heating in sodium ethoxide solution. The structures of the synthesized products were confirmed by IR,1H NMR, and mass spectral techniques.

Synthesis, reactions and biological activity of some new bis-heterocyclic ring compounds containing sulphur atom

BACKGROUND

The derivatives of thieno[2,3-b]thiophene belong to a significant category of heterocyclic compounds, which have shown a wide spectrum of medical and industrial application.

RESULTS

A new building block with two electrophilic center of thieno[2,3-b]thiophene derivatives 2 has been reported by one-pot reaction of diketone derivative 1 with Br2/AcOH in excellent yield. A variety of heteroaromatics having bis(1H-imidazo[1,2a] benzimidazole), bis(1H-imidazo[1,2-b][1,2,4]triazole)-3-methyl-4-phenylthieno[2,3-b]thiophene derivatives, dioxazolo-, dithiazolo-, and 1H-imidazolo-3-methyl-4-phenylthieno[2,3-b]thiophene derivatives as well pyrrolo, thiazolo -3-methyl-4-phenylthieno[2,3-b]thiophene derivatives have been designed, synthesized, characterized, and evaluated for their biological activity. Compounds 3-9 showed good bioassay result. These new derivatives were evaluated for anti-cancer activity against PC-3 cell lines, in vitro antioxidant potential and β-glucuronidase and α-glucosidase inhibitory activities. Compound 3 (IC50 = 56.26 ± 3.18 μM) showed a potent DPPH radical scavenging antioxidant activity and found to be more active than standard N-acetylcystein (IC50 = 105.9 ± 1.1 μM). Compounds 8a (IC50 = 13.2 ± 0.34 μM) and 8b (IC50 = 14.1 ± 0.28 μM) found as potent inhibitor of α-glucusidase several fold more active than the standard acarbose (IC50 = 841 ± 1.73 μM). Most promising results were obtained in β-glucuronidase enzyme inhibition assay. Compounds 5 (IC50 = 0.13 ± 0.019 μM), 6 (IC50 = 19.9 ± 0.285 μM), 8a (IC50 = 1.2 ± 0.0785 μM) and 9 (IC50 = 0.003 ± 0.09 μM) showed a potent inhibition of β-glucuronidase. Compound 9 was found to be several hundred fold more active than standard D-Saccharic acid 1,4-lactone (IC50 = 45.75 ± 2.16 μM).

CONCLUSIONS

Synthesis, characterization, and in vitro biological activity of a series of thieno[2,3-b]thiophene have been investigated.

1,3,4-Thiadiazoles of pharmacological interest: Recent trends in their synthesis via tandem 1,3-dipolar cycloaddition: Review

This review article presents a survey of the utility of a new synthetic strategy for 1,3,4-thiadiazole derivatives based on reactions of nitrilimines with various functionalized sulfur dipolarophiles which proceed via tandem in situ 1,3-dipolar cycloaddition and β-elimination of simple molecule from the initially formed cycloadduct. The biological activities of some of the compounds prepared by such a strategy are pointed out. Only the literature reports within the period from 2000 to mid 2012 are covered.