Antimicrobial activity of thiophene derivatives derived from ethyl (E)-5-(3-(dimethylamino)acryloyl)-4-methyl-2-(phenylamino)thiophene-3-carboxylate

Synthesis, Theoretical Study, and Anticonvulsant Evaluation of N-Arylenaminones

N-Arylenaminones are highly versatile compounds which can be synthesized in relatively simple ways. In this work we explored the synthesis of the four monosubstituted N-(4-R-phenyl)enaminones 3 a (R=NO2), 3 b (R=F), 3 c (R=H), and 3 d (R=OMe) with the goal of determining the influence of the substituents' electronic effects on tautomer stability and biological activity. These compounds were analyzed by means of Density Functional Theory calculations (DFT), to evaluate the relative stability of the possible tautomers. We found that the enaminone structure is the most stable with respect to the ketoimine and iminoenol forms. In addition, all four compounds display anticonvulsant activity, with 3 d being the one that mostly increased latency and mostly decreased the number of convulsions with respect to the control group. The suggested mechanism of action involves blockage of the voltage-dependent Na+ channels, considering that these molecules meet the structural characteristics needed to block the receptor, as is the case of the positive control molecules phenytoin (PHT) and valproic acid (VPA).

Carboxymethyl cellulose/sulfur-functionalized Ti-based MOF composite: synthesis, characterization, antimicrobial, antiviral and anticancer potentiality

Microbial resistance is the first morbidity and mortality cause for patients as usually a secondary infection. Additionally, the MOF is a promising material that shows a nice activity in this field. However, these materials need a good formulation to enhance biocompatibility and sustainability. Cellulose and its derivatives are well as filers for this gap. In this presented work, a novel green active system based on carboxymethyl cellulose and Ti-MOF (MIL-125-NH₂@CMC) modified with thiophene (Thio@MIL-125-NH₂@CMC) was prepared by a post-synthetic modification (PSM) route based. FTIR, SEM and PXRD were utilized to characterize nanocomposites. In addition, transmission electron microscopy (TEM) was used to corroborate the nanocomposites' particle size and diffraction pattern as well as the DLS affirmed the size as 50 and 35 nm for MIL-125-NH₂@CMC and Thio@MIL-125-NH₂@CMC, respectively. The formulation of the nanocomposites was validated by physicochemical characterization techniques, while morphological analysis confirmed the nanoform of the prepared composites. The antimicrobial, antiviral and antitumor properties of MIL-125-NH₂@CMC and Thio@MIL-125-NH₂@CMC were assessed. Antimicrobial testing revealed that Thio@MIL-125-NH₂@CMC possesses greater antimicrobial activity than MIL-125-NH₂@CMC. Additionally, Thio@MIL-125-NH₂@CMC demonstrated promising antifungal activity against C. albicans and A. niger where MICs were 31.25 and 0.97 µg/mL, respectively. Also, Thio@MIL-125-NH₂@CMC exhibited antibacterial activity against E. coli and S. aureus where MICs were 1000 and 250 µg/mL, respectively. In addition, the results demonstrated that Thio@MIL-125-NH₂@CMC displayed promising antiviral activity against both HSV1 and COX B4, with antiviral activities of 68.89% and 39.60%, respectively. Furthermore, Thio@MIL-125-NH₂@CMC exhibited potential anticancer activity against MCF7 and PC3 cancerous cell lines, where IC₅₀ was 93.16 and 88.45%, respectively. In conclusion, carboxymethyl cellulose/sulfur-functionalized Ti-based MOF composite was successfully synthesized which had antimicrobial, antiviral and anticancer activities.

Synthesis, Spectroscopic Characterization, Antibacterial Activity, and Computational Studies of Novel Pyridazinone Derivatives

In this work, a novel series of pyridazinone derivatives (3-17) were synthesized and characterized by NMR (¹H and ¹³C), FT-IR spectroscopies, and ESI-MS methods. All synthesized compounds were screened for their antibacterial activities against Staphylococcus aureus (Methicillin-resistant), Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, and Acinetobacter baumannii. Among the series, compounds 7 and 13 were found to be active against S. aureus (MRSA), P. aeruginosa, and A. baumannii with the lowest MIC value range of 3.74-8.92 µM. Afterwards, DFT calculations of B3LYP/6-31++G(d,p) level were carried out to investigate geometry structures, frontier molecular orbital, molecular electrostatic potential maps, and gap energies of the synthesized compounds. In addition, the activities of these compounds against various bacterial proteins were compared with molecular-docking calculations. Finally, ADMET studies were performed to investigate the possibility of using of the target compounds as drugs.

Silver(I) pyridinyl complexes with benzothiazole, thiophene, and furan moieties: DNA/protein-binding, antibacterial, antioxidant, and anticancer studies

We have synthesized and characterized nine Ag(I) complexes of Schiff bases containing thiophene, furan, and pyridine moieties for in vitro antibacterial, antioxidant, anticancer activities, and DNA/bovine serum albumin (BSA) binding studies. Based on the analytical and spectral analyses, a linear geometry was proposed for all the Ag(I) complexes, except for one (with the furan moiety), which formed a distorted T-shaped geometry. UV-vis absorption studies on the interactions of calf thymus-DNA (CT-DNA) with the nine Ag(I) complexes pointed to an intercalative binding mode. With a binding constant K_b of 3.75 × 10⁵ M^-1 , the complex bearing a benzothiazole moiety (1) interacted stronger with CT-DNA than the rest of the complexes. Fluorescence spectroscopic data revealed that the complexes had a modest binding affinity for BSA through static quenching. The complexes displayed good antioxidant properties, especially those with a benzothiazole moiety. Notable antibacterial activities against methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, Salmonella typhimurium, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae were observed for complexes with the furan and thiophene moieties. The in vitro anticancer studies of selected complexes against three cancer cell lines showed that the complexes were more effective against the inhibition of the growth of cervical cancer cells relative to cisplatin.

Promiscuous Lipase-Catalyzed Knoevenagel-Phospha-Michael Reaction for the Synthesis of Antimicrobial β-Phosphono Malonates

An enzymatic route for phosphorous–carbon bond formation was developed by discovering new promiscuous activity of lipase. We reported a new metal-free biocatalytic method for the synthesis of pharmacologically relevant β-phosphonomalononitriles via a lipase-catalyzed one-pot Knoevenagel–phospha–Michael reaction. We carefully analyzed the best conditions for the given reaction: the type of enzyme, temperature, and type of solvent. A series of target compounds was synthesized, with yields ranging from 43% to 93% by enzymatic reaction with Candida cylindracea (CcL) lipase as recyclable and, a few times, reusable catalyst. The advantages of this protocol are excellent yields, mild reaction conditions, low costs, and sustainability. The applicability of the same catalyst in the synthesis of β-phosphononitriles is also described. Further, the obtained compounds were validated as new potential antimicrobial agents with characteristic E. coli bacterial strains. The pivotal role of such a group of phosphonate derivatives on inhibitory activity against selected pathogenic E. coli strains was revealed. The observed results are especially important in the case of the increasing resistance of bacteria to various drugs and antibiotics. The impact of the β-phosphono malonate chemical structure on antimicrobial activity was demonstrated. The crucial role of the substituents attached to the aromatic ring on the inhibitory action against selected pathogenic E. coli strains was revealed. Among tested compounds, four β-phosphonate derivatives showed an antimicrobial activity profile similar to that obtained with currently used antibiotics such as ciprofloxacin, bleomycin, and cloxacillin. In addition, the obtained compounds constitute a convenient platform for further chemical functionalization, allowing for a convenient change in their biological activity profile. It should also be noted that the cost of the compounds obtained is low, which may be an attractive alternative to the currently used antimicrobial agents. The observed results are especially important because of the increasing resistance of bacteria to various drugs and antibiotics.

Thiophene-containing compounds with antimicrobial activity

Thiophene, as a member of the group of five-membered heterocycles containing one heteroatom, is one of the simplest heterocyclic systems. Many synthetic strategies allow the accurate positioning of various functionalities onto the thiophene ring. This review provides a comprehensive, systematic and detailed account of the developments in the field of antimicrobial compounds featuring at least one thiophene ring in their structure, over the last decade.

Synthesis of Azoloquinazolines and Substituted Benzothiazepine as Antimicrobial Agents

BACKGROUND & OBJECTIVE

Quinazolines and their fused systems are noteworthy in pharmaceutical chemistry due to their wide range of biological activities.

METHODS

A direct and efficient approach for the synthesis of new series of fused quinazolines with triazole, thiazole, benzimidazole and tetrazole has been preceded via the reaction of quinazoline thione derivative with halogenated compounds or cyclocondensation of arylidene of quinazoline derivative with heterocyclic amines. Also, dibenzo[b,e][1,4]thiazepine derivatives was synthesized through the reaction of 2,6-bis-(2-chloro-benzylidene)-cyclohexanone with o-aminothiophenol.

RESULTS

The structures of all new synthesized heterocyclic compounds were confirmed and discussed on the bases of spectral data. The utility of the preparation and design of the above mentioned compounds has been shown to be clear in the results of their antimicrobial activity which revealed that some derivatives have potent activity exceeding or similar to the activity of the reference drugs.

CONCLUSION

The insertion of triazole or thiazole moieties to be fused with quinazoline ring helps to enhance its antimicrobial activity.

Synthesis, ADMET Properties, and In Vitro Antimicrobial and Antibiofilm Activity of 5-Nitro-2-thiophenecarbaldehyde N-((E)-(5-Nitrothienyl)methylidene)hydrazone (KTU-286) against Staphylococcus aureus with Defined Resistance Mechanisms

The emergence of drug-resistant Staphylococcus aureus is responsible for high morbidity and mortality worldwide. New therapeutic options are needed to fight the increasing antimicrobial resistance among S. aureus in the clinical setting. We, therefore, characterized the in silico absorption, distribution, metabolism, elimination, and toxicity (ADMET) and in vitro antimicrobial activity of 5-nitro-2-thiophenecarbaldehyde N-((E)-(5-nitrothienyl)methylidene)hydrazone (KTU-286) against drug-resistant S. aureus strains with genetically defined resistance mechanisms. The antimicrobial activity of KTU-286 was determined by CLSI recommendations. The ADMET properties were estimated by using in silico modeling. The activity on biofilm integrity was examined by crystal violet assay. KTU-286 demonstrated low estimated toxicity and low skin permeability. The highest antimicrobial activity was observed among pan-susceptible (Pan-S) S. aureus (minimal inhibitory concentration (MIC) 0.5–2.0 µg/mL, IC₅₀ = 0.460 µg/mL), followed by vancomycin resistant S. aureus (VRSA) (MIC 4.0 µg/mL, IC₅₀ = 1.697 µg/mL) and methicillin-resistant S. aureus (MRSA) (MIC 1.0–16.0 µg/mL, IC₅₀ = 2.282 µg/mL). KTU-286 resulted in significant (p < 0.05) loss of S. aureus biofilm integrity in vitro. Further studies are needed for a better understanding of safety, synergistic relationship, and therapeutic potency of KTU-286.

Design, Synthesis and Antimicrobial Evaluation of 1,3,4‐Oxadiazole/1,2,4‐Triazole‐Substituted Thiophenes

The increasing level of antimicrobial resistance in pathogenic bacteria, together with the lack of new potential drug scaffolds in the pipeline, make the problem of infectious diseases a major public health concern. Thus, in this context, a novel series of 1,3,4‐oxadiazole‐substituted thiophenes (4 a–m) and 1,2,4‐triazole (6 a–m) substituted thiophene derivatives were synthesized. Characterization of all the synthesized derivatives was done by various spectroscopic techniques such as 1H NMR, 13C NMR spectroscopy and mass spectrometry, and evaluated for antimicrobial activity against various pathological strains using broth dilution and disc diffusion method. In particular, compound 6 e and 4 e exhibited significant inhibitory potential with MIC ranging from 2–7 μg mL−1 against S. aureus, B. subtilis, P. aeruginosa and E. coli. Additionally, compound 6 e was found to be highly potent against methicillin resistant S. aureus (MRSA; MIC=2 μg mL−1). Molecular docking studies were also performed to confer the possible mode of action and association studies indicate the binding of potent active compound with DHFR enzyme (Ka=2.10×103 M−1). Further, the mechanism of action has also been explored by atomic force microscopy (AFM), which reveals the bacterial cell wall deformity and cell wall rupturing that may lead to bacteria cell death. Additionally, in silico ADME prediction study suggested the drug like properties of active compounds.

Synthesis of Novel Bis-pyrazole Derivatives as Antimicrobial Agents

BACKGROUND

Bis-heterocycles especially those containing pyrazole moiety display much better antibacterial activity than mono heterocycles.

OBJECTIVE

Herein, we synthesised a series of new bis-pyrazoles and investigated their antimicrobial agents.

METHODS

A novel series of bis-pyrazole derivatives have been synthesized in good yield by coupling reaction of cyanoacetic acid {4-[(2-cyano-acetyl)-hydrazonomethyl]-benzylidene}-hydrazide with a number of diazonium salts of aromatic amines in DMF in the presence of NaOH. Refluxing of the produced hydrazones with hydrazine-hydrate in ethanolic solution afforded the respective bis-pyrazoles. On the other hand, the reaction of bis(cyanoacetic acid hydrazide) derivative with a diversity of hydrazonoyl chlorides in dioxane under reflux gave bis-pyrazoles.

RESULTS

The structures of all the products were discussed and assured from all possible spectral data as well as for the elemental analysis. In addition, the results of the antimicrobial activity examination of selected derivatives revealed a high strength of some tested compounds compared to standard bactericides and fungicides utilized. Molecular docking of the newly synthesized compounds into the Enoyl ACP reductase active site supported the in vitro antimicrobial activity. All the tested compounds could fit in the enzyme binding pocket with significant binding affinities (-7.040 to -9.141 Kcal/mol).

CONCLUSION

The good results of the antimicrobial examination of the newly synthesized bis-pyrazoles comprise the considerable evidence of the importance of bis-heterocyclic compounds which encourages us to continue designing and synthesising a novel series with potent biological activity in the future.

Design and synthesis of novel 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives bearing a hydrazone moiety as potential fungicides

BACKGROUND

Tetramic acid, thiophene and hydrazone derivatives were found to exhibit favorable antifungal activity. Aiming to discover novel template molecules with potent antifungal activity, a series of novel 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives containing a hydrazone group were designed, synthesized, and evaluated for their antifungal activity.

RESULTS

The structures of 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives bearing a hydrazone group were confirmed by FT-IR, 1H NMR, 13C NMR, 1H-1H NOESY, EI-MS and elemental analysis. Antifungal assays indicated that some title compounds exhibited antifungal activity against Fusarium graminearum (Fg), Rhizoctorzia solani (Rs), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc) in vitro. Strikingly, the EC50 value of 5e against Rs was 1.26 µg/mL, which is better than that of drazoxolon (1.77 µg/mL). Meanwhile, title compounds 5b, 5d, 5e-5g, 5n-5q and 5t exhibited remarkable anti-Cc activity, with corresponding EC50 values of 7.65, 9.97, 6.04, 6.66, 7.84, 7.59, 9.47, 5.52, 6.41 and 7.53 µg/mL, respectively, which are better than that of drazoxolon (19.46 µg/mL).

CONCLUSIONS

A series of 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives bearing a hydrazone group were designed, synthesized and evaluated for their antifungal activity against Fg, Rs, Bc and Cc. Bioassays indicated that some target compounds exhibited obvious antifungal activity against the above tested fungi. These results provide a significant basis for the further structural optimization of tetramic acid derivatives as potential fungicides.