Synthesis and Antimicrobial Activity of Some Novel [4‐(1,2,3‐thiadiazol‐4‐yl)phenoxy]methylene anchored 1,3,4‐triazoles and 1,3,4‐thiadiazoles

A series of novel [4‐(1,2,3‐thiadiazol‐4‐yl)phenoxy]methylene anchored 1,3,4‐triazoles ( 8a , 8b , 8c , 8d , 8e , 8f , 8g , 8h ) and 1,3,4‐thiadiazoles ( 9a , 9b , 9c , 9d , 9e , 9f , 9g , 9h , 9i ) were synthesized from thiosemicarbazide ( 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i , 7j ). The structures of these newly synthesized compounds were confirmed on the basis of IR, ¹H‐NMR, mass spectral techniques, and elemental analysis. The in vitro antimicrobial screenings of the synthesized compounds were carried out against four bacterial pathogens, namely Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Pseudomonas aeruginosa and three fungal pathogens Candida albicans, Aspergillus niger and Aspergillus clavatus, using broth microdilution minimum inhibitory concentration method. The compounds 7d , 7j , 8a , 9a , 9b , and 9i exhibited promising antibacterial activity against the tested strains, whereas some compounds were found to be active against one of the tested bacterial strains.     

Synthesis,Characterization and Biological Evaluation of a Novel Series of 1,2,4‐Triazolo‐[3,4‐b]‐1,3,4‐thiadiazines Containing an Amide Linkage

Two series of combinatorial library of 3,6‐disubstituted‐7H‐1,2,4‐triazolo‐[3,4‐b]‐1,3,4‐thiadiazines bearing an amide linkage were synthesized. All the newly synthesized compounds were characterized by spectral analyses. The newly synthesized compounds were screened for their cytotoxicity, anti‐inflammatory, and analgesic activities. Among the tested compounds, the compound 9g (Ar = 4‐(methoxybenzyl)piperazine) is the most promising molecule with half maximal inhibitory concentration (IC₅₀) value of 14.24 μM in (MCF‐7) cells. Compounds 9f (Ar = 4‐(chlorobenzyl)piperazine), 9g , and 9k (Ar = 2‐(fluorophenyl)piperazine) exhibited excellent anti‐inflammatory activity at a dose level of 50 mg/kg, almost comparable with the standard drug. In case of analgesic activity among the tested compounds, the compounds 9f , 9g , and 9k showed more potent and consistent activity in both 100 and 200 mg/kg/po doses with less ulcerogenic risk.     

Synthesis,Anticancer Evaluation,and Molecular Docking Studies of Novel (4‐Hydroxy‐2‐Thioxo‐3,4‐Dihydro‐2H‐[1,3]Thiazin‐6‐Yl)‐Chromen‐2‐Ones via a Multicomponent Approach

A series of coumarin‐substituted 1,3‐thiazine‐2‐thione derivatives ( 4a–m ) were synthesized via the multicomponent reaction of 3‐chloro‐3‐(2‐oxo‐2H‐chromen‐3‐yl)acrylaldehyde ( 1 ) carbon disulfide ( 2 ), and various primary amines ( 3 ), in presence of triethylamine and acetonitrile under stirring with good yields. The structures of all the synthesized compounds were characterized by analytical and spectral studies. Further, the synthesized compounds were screened for their in vitro antiproliferative activities against different cancer cell lines (A549, MDA‐MB‐231, MCF7, HeLa, and B16F10). Studies on the molecular interactions to recognize the hypothetical binding motif of the title compounds with the target Hsp 100 were carried out employing the Schrodinger software. Compounds 4a , 4c and 4m showed activity against all the five cell lines compared with the reference drug, and 4a exhibited the least IC₅₀ concentration of 7.56 ± 1.07 μg/mL against MCF7. This in vitro anticancer result was supported by in silico docking and in silico ADME (absorption, distribution, metabolism, and excretion) studies as well.     

新型5-(对氯苯基)-3-(邻，对-二氯苯基)-4，5-二氢吡唑肟酯衍生物的合成，结构表征及抗菌活性

合成了10个未见文献报道的1-(5-(2-氯苯基)-3-(2,4-二氯苯基)-4,5-二氢-N-吡唑肟酯类衍生物,并经过元素分析、HRMS、核磁共振氢谱对其结构进行了表征。对新合成的化合物进行了初步抗Bacillus subtilis, Staphylococcus aureus, Escherichia coli 和 Pseudomonas aeruginosa生物活性测试,结果表明:化合物7c 和7f对供试病菌具有较好的体外杀灭活性,其MIC值达到1.562 μg/mL;化合物7c ,7d和7f 具有中等的抑制DNA回旋酶活性(IC₅₀ = 1.6~2.5 µg/mL)。在生物活性结果的基础上对系列化合物的构效关系进行了初步的探讨。     

Novel Approach for Rapid and Efficient Synthesis of 2‐(3‐(4‐Aryl)‐1‐isonicotinoyl‐4,5‐dihydro‐1H‐pyrazol‐4‐yl)‐3‐phenylthiazolidin‐4‐one Derivatives and Screened Their Antimicrobial Activity

A series of compounds, viz. 2‐(3‐(4‐aryl)‐1‐isonicotinoyl‐4,5‐dihydro‐1H‐pyrazol‐4‐yl)‐3‐phenylthiazolidin‐4‐one 4 ( a – n ), have been synthesized by reaction of 3 ( a – n ) with thioglycolic acid in the presence of zinc chloride. Compounds 3 ( a – n ) have been synthesized by amination of formylated pyrazoles 2 ( A – B ), which were synthesized by formylation of 1 ( A – B ) by Vilsmeier–Haack reagent (POCl₃/DMF). Compounds 1 ( A – B ) were synthesized by condensation of hydrazide and substituted acetophenones under conventional method and microwave irradiation method. These compounds were identified on the basis of melting point range, Rf values, infrared, ¹H NMR, and mass spectral analysis. These compounds were evaluated for their in vitro antimicrobial activity, and their minimum inhibitory concentration was determined. Among them, compound 4b and compound 4l possess appreciable antimicrobial and antifungal activities. Antibacterial activity results showed that compounds containing electron‐withdrawing groups were more active than compounds containing electron‐releasing groups.     

Synthesis and Biological Activity of Novel Ethyl Esters of 4‐R‐6,8‐Dimethyl‐1‐oxo‐1,2‐dyhidropyrrolo[1,2‐d][1,2,4]triazine‐7‐carboxylic Acids

The novel heterocyclizations of ethyl 5‐(hydrazinocarbonyl)‐2,4‐dimethyl‐1H‐pyrrole‐3‐carboxylate are developed. New derivatives of ethyl esters of 4‐R‐6,8‐dimethyl‐1‐oxo‐1,2‐dyhidropyrrolo[1,2‐d][1,2,4]triazine‐7‐carboxylic acids were obtained. The in vitro anticancer and antibacterial activities of the synthesized compounds were revealed. The most potent antibacterial compound appeared to be 1.3 inhibiting Staphylococcus aureus. Pyrrolo[1,2‐d][1,2,4]triazine 2.15 showed significant antifungal activity against Candida tenuis. The anticancer activity of the synthesized compounds was determined.     

Synthesis,Characterization, and Antimicrobial Screening of 4″‐methyl‐2,2″‐diaryl‐4,2′:4′,5″‐terthiazole Derivatives

A series of novel 4″‐methyl‐2,2″‐diaryl‐4,2′:4′,5″‐terthiazole ( 8a‐p ) derivatives has been synthesized and screened for antibacterial activity against four pathogenic bacteria, Escherichia coli, Pseudomonas flurescence, Staphylococcus aureus, and Bacillus subtilis. Among them, compounds 8a and 8j exhibited excellent antibacterial activity with minimum inhibitory concentration range of 1.0 to 5.3 μg/mL and compounds 8m and 8p exhibited moderate to good antibacterial activity with minimum inhibitory concentration range of 16.9 to 29.7 μg/mL against all tested strains. All the synthesized compounds were screened for their in vitro antifungal activity against Cocinida candida. Most of the compounds reported moderate antifungal activity. This study provides valuable directions to our ongoing endeavor of rationally designing more potent antimicrobial agent.     

Synthesis and Antimicrobial Evaluations of Some Novel Mono‐, Bis‐, and Tris‐Nitro‐1,2,4‐Triazines

Substituted‐1,2,4‐triazines were conveniently synthesized in one pot by the cyclization of arylnitroformaldehyde hydrazone derivatives 1 and 5 with different primary amines in ~37% formaldehyde solution. The synthesized compounds were arranged into novel mono‐, bis‐, and tris‐nitro‐1,2,4‐triazine derivatives 2 , 3 , 4 , 6 , and 7 . The antibacterial and antifungal activity of the synthesized compounds were screened against bacterial strains Escherichia coli (as Gram − ve) and Staphylococcus aureus (as Gram + ve), and fungal strains Aspergillus flavus and Candida albicans . All the synthesized compounds exhibit various patterns of inhibitory activity on the two pathogenic bacterial strains. However, the same compounds showed no activity against the tested fungal strains.     

Synthesis and Herbicidal Activity of Novel 4‐Acyl‐2,5‐disubstituted‐3‐hydroxypyrazoles and 4‐Arylcarbonyl‐3‐substitutedisoxazol‐5‐ones

Two series of novel 4‐acyl‐2,5‐disubstituted‐3‐hydroxypyrazoles 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h and 4‐arylcarbonyl‐3‐substitutedisoxazol‐5‐ones 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i were synthesized by the Scotton–Baumann reaction of 2,5‐disubstituted‐2,4‐dihydro‐pyrazol‐3‐ones 1 or 3‐substituted‐4H‐isoxazol‐5‐ones 6 and various acyl chlorides, followed by the Fries rearrangement in the presence of calcium hydroxide and calcium oxide as the catalyst. Their structures were confirmed by IR, ¹H NMR, mass spectroscopy, and elemental analyses. ¹H NMR indicated that compounds 3 existed in enol forms and compounds 7 in keto configurations. The results of preliminary bioassays showed that some of the title compounds 3 and 7 exhibited moderate to good herbicidal activities against Brassica campestris L. at the concentration of 100 mg/L. Isoxazole compounds 7 showed better herbicidal activity against B. campestris L. than pyrazole compounds 3 did at the concentration of 100 mg/L. Moreover, most of the isoxazole compounds displayed higher herbicidal activity against B. campestris L. than Echinochloa crus‐galli. However, these compounds showed weak herbicidal activities at the concentration of 10 mg/L.     

A Facial Synthesis and Anticancer Activity of (Z)‐2‐((5‐(4‐nitrobenzylidene)‐4‐oxo‐4,5‐dihydrothiazol‐2‐yl)amino)‐substituted Acid

In order to explore the anticancer and antimicrobial activity associated with the thiazole framework, we synthesized the new series (Z )‐2‐((5‐(4‐nitrobenzylidene)‐4‐oxo‐4,5‐dihydrothiazol‐2‐yl)amino)‐substituted acid derivatives 6a – l . All the synthesized compounds were evaluated for anticancer and antimicrobial activity in vitro. Among these, the compounds 6a , 6b, 6c , 6e , 6f , 6g , 6h , 6i , 6j , and 6k showed highest antibacterial and antifungal activity. The compound 6a exhibited significant antibacterial activity against Bacillus subtilis , whereas compound 6j displays significant antifungal activity against fungal strains, that is, A. oryzae . The in vitro anticancer studies revealed that 6e , 6g , 6h , 6k , and 6l are the most active compounds against MCF‐7 and BT‐474 human breast cancer cell lines, which can be regarded as the promising drug candidate for development of anticancer drugs.     

4‐Aryl‐4H‐Chromene‐3‐Carbonitrile Derivates: Synthesis and Preliminary Anti‐Breast Cancer Studies

A series of new 4‐aryl‐4H‐chromene‐3‐carbonitrile derivatives were obtained by one‐pot synthesis using substituted benzaldehydes, malononitrile, and substituted phenols. All the synthesized compounds ( 1a , 1b , 1c , 1d , 1e ) were screened in vitro for antioxidant and anticancer activities. Compounds 1c , 1d , 1e showed significant antioxidant activity in nitric oxide free radical scavenging method while compounds 1c and 1e showed significant activity in hydrogen peroxide free radical scavenging method. The other compounds showed significant to moderate activities in both the methods in comparison with ascorbic acid and butylated hydroxytoluene as standards. Compounds 1c , 1d , 1e exhibited good anticancer activity, using Michigan Cancer Foundation‐7 (MCF‐7) cell line, compared with those of other synthesized compounds.     

A “One Pot,” Environmentally Friendly,Multicomponent Synthesis of 2‐Amino‐5‐cyano‐4‐[(2‐aryl)‐1H‐indol‐3‐yl]‐6‐hydroxypyrimidines and Their Antimicrobial Activity

A series of multifunctional 2‐amino‐5‐cyano‐4‐[(2‐aryl)‐1H‐indol‐3‐yl]‐6‐hydroxypyrimidines ( 4a , 4b , 4c , 4d , 4e , 4f ) was synthesized by multicomponent reaction of 3‐formylindole ( 1 ), cyanoethylacetate ( 2 ), and guanidine hydrochloride ( 3 ) with NaOH by using green chemical techniques, viz. microwave irradiation and grindstone technology. The same reactants when refluxed in ethanol also gave titled compounds ( 4a , 4b , 4c , 4d , 4e , 4f ). Compared with conventional procedure, the reaction can be carried out under milder conditions, requiring a shorter reaction time and giving higher yields following the green chemistry methodology. All the synthesized compounds have been characterized on the basis of elemental analyses and spectral data (IR, ¹H NMR, ¹³C NMR, and mass). All synthesized compounds were also evaluated for their antimicrobial activity against nine pathogenic bacteria, antifungal activity against Rhizopus stolonifer, Aspergillus flavus, and Fusarium oxysporum and antibacterial activity against Escherichia coli and Pseudomonas aeruginosa at different concentrations. Most of the compounds showed mild to moderate activity.     

Synthesis and Biological Evaluation of Some New N1‐[4‐(4‐Chlorophenylsulfonyl)benzoyl]‐N 4‐(aryl)‐thiosemicarbazides and Products of Their Cyclization

In the present study, new 1,2,4‐triazoles, 1,3,4‐thiadiazoles, and acylthiosemicarbaz‐ides derived from 4‐(4‐chlorophenylsulfonyl)benzoic acid hydrazide were synthesized and screened for their antimicrobial and analgesic activities. Acylthiosemicarbazides 2–4 were synthesized by a reaction of 4‐(4‐chlorophenyl‐sulfonyl)benzoic acid hydrazide 1 with different arylisothiocyanates.4,5‐Disubstituted‐2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐thiones 5–7 and 2,5‐disubstituted‐1,3,4‐thiadiazoles 8–10 were obtained by dehydrative cyclization of corresponding acylthiosemicarbazide derivatives 2–4 in basic media (8% aqueous sodium hydroxide) and in acidic media (sulfuric acid or phosphorous oxychloride), respectively. The structures of the newly synthesized compounds have been confirmed on the basis of elemental analysis and spectral studies (IR, ¹H NMR, ¹³C NMR, MS). Their antimicrobial activities against some bacteria and yeasts were investigated. The analgesic activity of all compounds was performed with two pharmacological tests: the writhing test induced with acetic acid and hot‐plate test. The results showed that triazole 7 had the best antimicrobial activity against Bacillus cereus. In the chemical stimulus test, triazoles 6 and 7 were the most active compounds whereas in the hot‐plate test thiadiazoles 9 and 10 exhibited the highest analgesic activity.     

Design,synthesis of (Z)‐3‐benzyl‐5‐((1‐phenyl‐3‐(3‐((1‐ substituted phenyl‐1H‐1,2,3‐triazol‐4‐yl)methoxy)phenyl)‐1H‐pyrazol‐4‐yl)methylene)thiazolidine‐2,4‐dione analogues as potential cytotoxic agents

In an attempt to achieve promising cytotoxic agents, a series of new (Z)‐3‐benzyl‐5‐((1‐phenyl‐3‐(3‐((1‐substituted phenyl‐1H‐1,2,3‐triazol‐4‐yl)methoxy)phenyl)‐1H‐pyrazol‐4‐yl)methylene)thiazolidine‐2,4‐diones 10 a‐n were designed, synthesized, and characterized by ¹H NMR, ¹³C NMR, IR, and ESI‐MS techniques. These compounds synthesized from appropriate reaction procedures with better yields. All the novel synthesized compounds 10a‐n were evaluated for their cytotoxic activity against the MCF‐7 cell line (Human breast cancer cell line) at different concentrations of 0.625, 1.25, 2.5, 5, and 10 μM, respectively. The cytotoxic evaluation assay is presented in terms of IC₅₀ values and percentage cell viability reduction compared against standard drug cisplatin. Among all novel synthesized compounds 10a‐n , some of the representative analogues particularly 10g and 10e exhibit remarkable cytotoxic activity with IC₅₀ values 0.454 and 0.586 μM, comparable to that of the standard drug cisplatin, and some analogues 10d , 10f , 10k, and 10m also have shown significant activity.     

Synthesis and Antimicrobial Screening of 2‐Aryl‐5‐((2‐arylthiazol‐4‐yl)methyl)‐1,3,4‐oxadiazole Derivatives

A new series of 2‐aryl‐5‐((2‐arylthiazol‐4‐yl)methyl)‐1,3,4‐oxadiazole derivatives was synthesized by condensation of 2‐(2‐substituted thiazol‐4‐yl)acetohydrazide with aryl aldehydes followed by oxidative cyclocondensation using iodobenzene diacetate. The structure of synthesized compounds was characterized by IR, NMR, and mass analysis. All the newly synthesized compounds were evaluated for their in vitro antimicrobial activity. Some of the compounds showed moderate antimicrobial activity.     

Facile Synthesis of Novel 3‐(4‐phenylisothiazol‐5‐yl)‐2H‐chromen‐2‐one Derivatives as Potential Anticancer Agents

A series of 3‐(4‐phenylisothiazol‐5‐yl)‐2H‐chromen‐2‐one ( 6a – l ) derivatives has been efficiently synthesized by straightforward sequential reactions. Tandem Vilsmeier Hack reaction/cyclization/bromination/Suzuki cross‐coupling reactions were successfully applied to the preparation of title compounds in good‐to‐high yields. In the synthetic sequences, 3‐chloro‐3‐(2‐oxo‐2H‐chromen‐3‐yl)acrylaldehydes ( 2 ) were found to react with ammonium thiocyanate to yield the corresponding 3‐(isothiazol‐5‐yl)‐2H‐chromen‐2‐ones ( 3 ). These derivatives were brominated with N‐bromo succinamide to yield the corresponding regioselective 3‐(4‐bromoisothiazol‐5‐yl)‐2H‐chromen‐2‐one ( 4 ). Finally, compound 4 was treated with various phenyl/pyrazole/7H –pyrrolo[2,3‐d]pyrimidinyl boronic acids 5a – l in the presence of K₂CO₃ and Pd catalyst in dimethylformamide to yield the corresponding title derivatives 6a – l . All the synthesized compounds were characterized by analytical and spectral studies. All the final compounds were screened against different cancer cell lines (A549, PC3, SKOV3, and B16F10), and among these compounds, 6b , 6g , 6h , and 6l displayed moderate cytotoxic activity against the tested cell lines.     

Palladium Catalyzed Tricyclohexylphosphine Ligand Associated Synthesis of N‐(2‐(pyridine‐4‐yl)‐1H‐pyrrolo[3,2‐c]‐pyridin‐6‐yl‐(substituted)‐sulfonamide Derivatives as Antiproliferative Agents

A series of novel N‐(2‐(pyridine‐4‐yl)‐1H‐pyrrolo[3,2‐c]‐pyridin‐6‐yl‐(substituted)‐sulfonamide derivatives were synthesized from 2‐bromo‐6‐nitro‐1H‐pyrrolo[3,2‐c]pyridine through a series of reactions including Suzuki reaction, reduction, protection, and sulfonamide coupling. All the synthesized compounds were screened for anticancer activity against MCF‐7, HeLa, A‐549, and Du‐145 cancer cell lines by the MTT assay. The preliminary bioassay suggests that most of the compounds show antiproliferation with different degrees. Doxorubicin was used as a positive control. Among the synthesized compounds, 8d and 8h were most active compared with the standard in cell line data. The synthesized compounds 8d and 8h show IC₅₀ values in the range of 1.88–5.16 μM for all the cell lines. Compounds 8d and 8h were further studied for a panel of eight human kinase at 10 μM concentrations and the result shows 64% to 70% inhibitions for both Aurora‐A and Aurora‐B kinase.     

Synthesis and Bioactivities of Novel 1‐(3‐Chloropyridin‐2‐yl)‐N‐Substituted‐5‐(Trifluoromethyl)‐Pyrazole Carboxamide Derivatives

A series of novel 1‐(3‐chloropyridin‐2‐yl)‐N‐substituted‐5‐(trifluoromethyl)‐pyrazole carboxamide derivatives TC₁ , TC₂ , TC₃ , TC₄ , TC₅ , TC₆ , TC₇ , TC₈ , TC₉ , TC₁₀ , TC₁₁ were synthesized and characterized by IR, ¹H NMR, ¹³C NMR, MS, and elemental analysis. All the target compounds were tested in vitro for their antibacterial activities and antifungal activities. The preliminary bioassays indicated that compound TC₆ exhibited excellent activity against Xanthomonas oryzae (94.9% and 84.9%) at different concentrations (200 µg/mL and 100 µg/mL), which was higher than that of Bismerthiazol (94.6% and 64.0%), respectively. At the same time, most of the compounds exhibited moderate antifungal activities against four kinds of phytopathogenic fungi     

Synthesis and Antimicrobial Activities of Novel Series of 3‐(4‐(2‐substituted thiazol‐4‐yl)phenyl)‐2‐(4‐methyl‐2‐substituted thiazol‐5‐yl)thiazolidin‐4‐one Derivatives

In the present investigation, a novel series of 3‐(4‐(2‐substituted thiazol‐4‐yl)phenyl)‐2‐(4‐methyl‐2‐substituted thiazol‐5‐yl)thiazolidin‐4‐one derivatives were synthesized by condensation of 2‐substituted‐4‐methylthiazole‐5‐carbaldehyde with 4‐(2‐substituted thiazol‐4‐yl)benzenamine followed by cyclo‐condensation with thioglycolic acid in toluene. All the newly synthesized compounds were characterized by spectral (IR, ¹H NMR, ¹³C NMR, and Mass) methods. The title compounds were screened for quantitative antibacterial activity (minimal inhibitory concentration). All compounds 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h and 8a , 8b , 8c , 8d , 8e , 8f , 8g , 8h show moderate to good antimicrobial activity, whereas compounds ( 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h ) also show moderate antifungal activity.     

Synthesis and antimicrobial activity of some 7‐aryl‐5,6‐dihydro‐14‐aza[1]benzopyrano[3,4‐b]phenanthren‐8H‐ones

The title compounds, 7‐aryl‐5,6‐dihydro‐14‐aza[1]benzopyrano[3,4‐b]phenanthren‐8H‐ones 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , 3l have been synthesized by reacting various 4‐hydroxy coumarins 1a , 1b , 1c with 2‐arylidene‐1‐tetralones 2a , 2b , 2c , 2d in the presence of ammonium acetate and acetic acid under Krohnke's reaction condition. The structures of all the synthesized compounds were supported by analytical, IR, ¹H‐NMR, and ¹³C‐NMR data. All the synthesized compounds 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , 3l have been screened for their antibacterial activities against Escherichia coli (Gram ?ve bacteria), Bacillus subtilis (Gram +ve bacteria), and antifungal activity against Candida albicans (Fungi). J. Heterocyclic Chem., (2011).