Novel 1,3,4‐Oxadiazole Derivatives of Dihydropyrimidinones: Synthesis,Anti‐Inflammatory,Anthelmintic, and Antibacterial Activity Evaluation

The present study depicts synthesis of a series of some novel 5‐(5‐(aryl)‐1,3,4‐oxadiazol‐2‐yl)‐3,4‐dihydro‐6‐methyl‐4‐styrylpyrimidin‐2(1H)‐one derivatives. All the newly synthesized compounds were characterized by FTIR, ¹H NMR, ¹³C NMR, mass spectrometry, and elemental analysis. The compounds were evaluated for their in vivo anti‐inflammatory activity by the carrageenan‐induced rat paw edema method. The compounds were also screened for their anthelmintic activity on Indian earthworms and antibacterial activity against some gram positive and gram negative strains of bacteria. This pharmacological activity evaluation revealed that, among all the compounds screened, compounds 4b and 4c were found to have promising anti‐inflammatory activity. Interestingly, compounds 4b , 4c , and 4i exhibited appreciable anthelmintic property, while compounds 4c , 4g , and 4h showed leading antibacterial activity against the selected pathogenic strains of bacteria.     

Synthesis and Evaluation of Antimicrobial Activity of Some New Hetaryl‐Azoles Derivatives Obtained from 2‐Aryl‐4‐methylthiazol‐5‐carbohydrazides and Isonicotinic Acid Hydrazide

A series of new 1,3,4‐oxadiazole/thiadiazole and 1,2,4‐triazole derivatives have been synthesized starting from 2‐aryl‐4‐methylthiazol‐5‐carbohydrazides and isonicotinic acid hydrazide. All the newly synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR, and mass spectrometry. The synthesized compounds were screened for their antibacterial and antifungal activity, assessed as growth inhibition diameter. Some of them showed good antibacterial activity against gram positive Staphylococcus aureus, while the antibacterial activity against Listeria monocytogenes, Escherichia coli, and Salmonella typhymurium and antifungal activity against Candida albicans was modest. None of the tested compounds showed inhibitory activity against gram positive bacteria Enterococcus faecalis and Bacillus cereus and against gram negative bacteria Pseudomonas aeruginosa.     

Diverse synthetic approach for sulfur and nitrogen-containing spiroheterocycles from dimedone and their pharmacological evaluation

Novel spiro(3-hydroxy-5,5-dimethyl)-1,5’-(2’-substituated[1,3,4]-oxadiazole/thiadiazolo[3,2-c] thiazolines and 3-hydroxy-5,5-dimethyl-spiro[cyclohex-2-ene-thiazolo/thiazino[3,2-b]-s-tetrazine were prepared from previously reported hydrazone, semicarbazone, carbazone, and spiro-s-tetrazine intermediates derived from dimedone precursor. All the newly synthesized heterocycles have been characterized by analytical and spectral (¹H NMR and ^hC NMR) data and screened their in vitro antibacterial activity against gram negative bacteria Escherichia coli and gram positive bacteria Staphylococcus aureus. Some of the compounds showed moderate to good activities towards the bacteria chosen.     

含脱羧脱氢松香基的1,2,4-三唑并[3,4-b]-1,3,4-噻二唑衍生物的合成、表征及抑菌活性

用POCl3为催化剂和脱水剂,3-取代-4-氨基-5-巯基-1,2,4-三唑4和10分别与脱氢松香酸1反应制得14种未见文献报道的3-取代-6-(4′-脱羧脱氢松香基)-1,2,4-三唑并[3,4-b-]-1,3,4-噻二唑衍生物]5a~5e和11a~11i;所有化合物的结构均经IR、¹H NMR、¹³C NMR 和MS测试技术分析确认。 抑菌活性测试表明,目标化合物对白色念珠菌(C.Albicans)、大肠杆菌(E.Coli)、藤黄微球菌(M.Luteus)和痢疾志贺杆菌(S.Dysenteriae)均有一定的抑制作用。     

One-pot synthesis, antibacterial and antifungal activities of novel 2,5-disubstituted-1,3,4-oxadiazoles

A series of novel 2,5-disubstituted-1,3,4-oxadiazoles have been synthesized from long-chain alkanoic and alkenoic acids. The structures of these compounds have been elucidated by elemental and spectral （IR, ^1H NMR, ^13C NMR, MS） analysis. Furthermore, compounds were screened for in vitro antibacterial activity against the representative panel of two Gram-positive and two Gram- negative bacteria. All the synthesized compounds were also tested for their inhibitory action against five strains of fungus. The various compounds show potent inhibitory action against test organisms. 2007 Abdul Rauf. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

Synthesis of novel naphtho[1,2-e][1,3]oxazines bearing an arylsulfonamide moiety and their anticancer and antifungal activity evaluations

A series of novel naphtho[1,2-e][1,3]oxazines bearing arylsulfonamide moiety have been synthesized via a one-pot approach and in a green reaction medium. These new naphtho[1,2-e][1,3]oxazine derivatives have been characterized by their ¹H NMR, ¹³C NMR and the X-ray single crystallography method for compound 7a. All the newly synthesized compounds were examined for their in vitro anticancer activity against breast (MCF-7), colon (HCT116), and B-CLL (Waco3-CD5) cancers. Some of these compounds such as 7j and 7l showed remarkable activities against MCF-7 (breast) and HCT116 (colon) cancers with comparable IC₅₀ (The half maximal inhibitory concentration) values as that of known drugs such as 5-fluorouracil (5-FU). In vitro antimicrobial activities of all compounds were also evaluated against five human pathogenic fungi strains and two bacteria (one gram positive and one gram negative). The best MICs (Minimum Inhibitory Concentrations) were found against the C. albicans.     

Synthesis,Structures, and Fungitoxicity of Novel Organophosphorus Compounds

Abstract

A series of biologically active organophosphorus compounds have been synthesized by the reactions of O,O-diethylchlorophosphate with Schiff bases derived from 5-(phenyl/substituted phenyl)-2-hydrazino-1,3,4-oxadiazole and salicylaldehyde/2-hydroxyacetophenone. The compounds have been characterized on the basis of analyses and spectral (IR, ¹H, ¹³C NMR) data. Fungicidal activities of these derivatives against Colletotrichum falcatum, Fusarium oxysporum, and Curvularia pallescence have been evaluated. All compounds showed moderate to significant antifungal activity.     

Design,synthesis, and characterization of some new benzimidazole derivatives and biological evaluation

A new series of benzimidazole derivatives ( 1-15 ) containing 1,2,4-triazole, 1,3,4-thiadiazole, 1,3,4-oxadiazole, and thiazolidinon rings have been synthesized. All new synthesized benzimidazole compounds were confirmed by ¹H NMR, ¹³C NMR spectra, and LC-MS, and they were examined for their antioxidant and antimicrobial activities. Compounds 7 and 1 showed the highest and the lowest antioxidant activities, respectively. The lowest minimum inhibition concentration value found in compound 5 against Enterobacter aerogenes.     

Design,synthesis and biological evaluation of novel N1,N8-bis(((4-((5-aryl-1,3,4-oxadiazol-2-yl)methoxy)phenyl)amino)oxy)-1-naphthamide derivatives

A new series of 1,8-bis(4-((5-phenyl-1,3,4-oxadiazol-2-yl) methoxy)-substituted aryl) naphthalene-1,8-dicarboxamide derivatives (6a–j) were synthesized in the presence of POCl₃ and obtained good yields. All the synthesized novel compounds were characterized by IR, ¹H NMR, ¹³C NMR, HRMS spectroscopic data and elemental analysis. All the synthesized compounds evaluated for their antibacterial and antifungal activities. The antibacterial activity screened against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli and used standard reference drug ciprofloxacin. The antifungal activity screened against two pathogenic fungal strains Aspergillus niger and Candida albicans used a reference standard drug Voriconazole. All these compounds (6a–j) demonstrate good antibacterial and antifungal activity. Among them, compounds 6h and 6c show highest antibacterial and antifungal activity.     

Synthesis, biological and computational study of new Schiff base hydrazones bearing 3-(4-pyridine)-5-mercapto-1,2,4-triazole moiety

A series of new Schiff base hydrazones (compounds 1-16) were synthesized by condensation reaction of 4-amino-3-(4-pyridine)-5-mercapto-1,2,4-triazole with various aldehydes and/or dialdehydes. The structure of the prepared compounds was confirmed by means of 1H NMR, 13C NMR, UV-vis, IR and elemental analyses. The all prepared compounds were assayed for antibacterial (Escherichia coli and Staphylococcus aureus) and antifungal (Candida albicans) activities by disc diffusion method. The results indicate that all tested compounds did not show any antibacterial activity against E. coli, as gram negative bacteria, and antifungal activity against C. albicans. But the compounds 2, 3, 4, 6 and 8 containing 4-Cl, 4-Me, 4-MeO, 2,4-di-Cl and 2-OH substituted phenyl moiety, respectively, showed good inhibition against S. aureus as compare to standard drugs. The structure of all biologically active compounds has also been theoretically studied by ab initio Hartree-Fock (HF) methods.     

Design,Synthesis, and Biological Evaluation of Novel 1,3,4‐Thiadiazolylpyrazolines Compounds Containing Ferrocene

The synthesis of 1,3,4‐thiadiazole skeleton compounds exhibiting high fungicidal activities has been demonstrated. Thirteen novel 1,3,4‐thiadiazolyl‐pyrazolines compounds containing ferrocene were designed and synthesized from the ferrocenylchalcones intermediates 3a – 3m and the 2‐hydrazino‐5‐phenyl‐1,3,4‐thiadiazole intermediate 8 . All compounds were characterized by ¹H NMR, ¹³C NMR, FT‐IR spectra, and HR‐MS, and the structure of one of the new compounds N‐(4‐phenyl‐1,3,4‐thiadiazol‐2‐yl)‐3‐ferrocenyl‐5‐phenyl‐pyrazoline 9a was further determined by X‐ray diffraction analysis. The preliminary results of a biological activity assay indicated that all the title compounds exhibited significant fungicidal activities against Pythium solani, Gibberella saubinetii, and Gibberella nicotiancola. Furthermore, compounds 9e and 9h displayed even higher fungicidal activities against the three fungal species compared with the control drug pyraclostrobin.     

3-杂环硫亚甲基头孢菌素衍生物的半合成及抗菌活性研究

通过取代噁二唑硫酮、噻二唑硫酮及三唑硫酮分别和头孢菌素母体7-ACA反应,制得14种7-氨基-3-杂环硫亚甲基头孢菌素新母体2a-2n,用1-芳基-5-甲基-1H-1,2,3-三唑-4-甲酰氯与头孢菌素新母体缩合,制得2种新的7β-(1-芳基-5-甲基-1H-1,2,3-三唑-4-甲酰胺基)-3-(2-取代1,3,4-bI二唑-5-硫亚甲基)头孢菌素4c,4d.新化合物结构经元素分析、IR、¹HNMR及FAB-MS确认.初步体外抗菌结果表明,新母体化合物2对革兰氏阳性菌有抑制活性且在相同浓度下比7-ACA强20倍,而头孢菌素4c,4d对革兰氏阳性和阴性菌都有显著抑制活性.     

Synthesis,characterization and biological activity of Hg(II), Fe(III) complexes with 1,3,4-oxadiazole, 1,2,4-triazole derivatives from L-methionine

Four novel heterocyclic1,3,4-oxadiazole, 1,2,4-triazole derivatives, namely: 5-[1-amino-3-(methylsulfanyl)propyl]-1,3,4-oxadiazole-2(3H)-thione (4), 4-amino-5-[1-amino-3-(methylsulfanyl)propyl]-4H-1,2,4-triazole-3-thiol (5), 1-amino-3-[1-amino-3-(methylsulfanyl)propyl]-1H-1,2,4-triazole-5-thiol (7), and 5-[1-amino-3-(methylsulfanyl)propyl]-1H-1,2,4-triazole-3-thiol (9) have been synthesized from l-methionine and characterized by different spectroscopic techniques (FT-IR, UV–Vis, ¹H NMR, ¹³C NMR and MS). Complex formation with Hg⁺⁺ and Fe⁺⁺⁺ ions were formed from the four heterocyclic 4, 5, 7 and 9. The antimicrobial activities for synthetic intermediates and final four products were assisted using paper disk diffusion method against Gram-negative bacteria: Escherichia coli, Pseudomonas aeroginosae and Gram-positive bacteria: Staphylococus aureus 25923, Staphylococus aureus 43300 and showed variant activity against some of the microorganisms tested.     

Design,Synthesis, Antimicrobial,and Antioxidant Activity of Dimers of Chromene Containing 1,2,3-Triazole Derivatives Bearing an Alkyl Spacer

A new series of chromene based 1,2,3-triazole derivatives has been synthesized by incorporating biologically active heterocyclic rings containing chromene and triazole moieties in one molecular structure. All newly synthesized compounds are characterized by ¹H and ¹³C NMR, mass, and IR spectra. The title compounds are tested for their activity against different bacterial and fungal strains, and antioxidant activity. Several compounds are determined to be potent antimicrobial and antioxidant agents.

     

Synthesis,Characterization, and Antimicrobial Evaluation of Quinoline-Oxadiazole–Based Azetidinone Derivatives

A series of 3-chloro-1-(aryl)-4-(2-(2-chloroquinolin-3-yl)-5-(pyridin-4-yl)-1,3,4-oxadiazol-3(2H)-yl)-4-ethyl-azetidin-2-ones (5a–l) have been synthesized and characterized by IR, ¹H NMR, and¹³C NMR. Synthesized compounds were screened for their antimicrobial activity against different strains of bacteria (E. coli, P. aeruginosa, S. aureus, S. pyogenes, C. albicans, A. niger, and A. clavatus). On the basis of statistical analysis, it has been observed that compounds had significant correlations.     

4-烷氧/苄氧基苯基四唑和1,3,4-噁二唑类化合物的合成及除草活性

以4-氰基苯酚为起始原料, 在4-烷氧基/苄氧基苯甲脒结构基础上, 设计合成了5个4-烷氧基/苄氧基苯基四唑及17个新型2-取代-5-(4-烷氧基/苄氧基)苯基噁二唑类化合物, 通过元素分析、1H NMR和MS对所合成的新化合物进行了结构表征. 初步除草活性测试结果表明, 部分化合物对双子叶油菜和单子叶稗草表现出较好的生长抑制活性.     

4-烷氧/苄氧基苯基四唑和1,3,4-噁二唑类化合物的合成及除草活性

以4-氰基苯酚为起始原料,在4-烷氧基/苄氧基苯甲脒结构基础上,设计合成了5个4-烷氧基/苄氧基苯基四唑及17个新型2-取代-5-(4-烷氧基/苄氧基)苯基噁二唑类化合物,通过元素分析、1H NMR和MS对所合成的新化合物进行了结构表征.初步除草活性测试结果表明,部分化合物对双子叶油菜和单子叶稗草表现出较好的生长抑制活性.     

N-[5-(4-吡啶基)-1,3,4-噻二唑-2-基]-N'-芳酰基脲的合成与生物活性

为了寻找高活性的含杂环的新农药, 通过2-氨基-5-(4-吡啶基)-1,3,4-噻二唑与芳酰基异氰酸酯反应, 合成了17种新的芳酰基脲, 采用红外光谱、核磁共振氢谱与元素分析证明了其结构. 初步的活性试验表明, 部分目标化合物具有良好的植物生长调节活性, 其中2c, 2e, 2f, 2i和2k具有较好的细胞分裂素活性.     

[5-(芳亚甲基氨基)-1,3,4-噻二唑-2-基]硫乙酰芳胺的合成及 生物活性研究

在K2CO3存在下利用聚乙二醇-400 (PEG-400)作相转移催化剂, 于固-液相转移催化条件下, 通过5-芳亚甲基氨 基-2-巯基-1,3,4-噻二唑与氯乙酰芳胺的硫烷基化反应, 合成了16个未见文献报道的[5-(芳亚甲基氨基)-1,3,4-噻二唑-2-基]硫乙酰芳胺衍生物. 经元素分析, FT-IR,1H NMR和13C NMR确证了其结构. 生物活性实验结果表明, 部分化合物对小麦幼苗的生长具有明显的植物生长调节活性, 并对枯草杆菌具有一定的抑制活性.     

Insertion of CO2, ketones, and aldehydes into the C-Li bond of 1,3,5-triaza-7-phosphaadamantan-6-yllithium

The synthesis and structures of a series of new water-soluble phosphine ligands based on 1,3,5-triaza-7-phosphaadamantane (PTA) are described. Insertion of aldehydes or ketones into the C-Li bond of 1,3,5-triaza-7-phosphaadamantan-6-yllithium (PTA-Li) resulted in the formation of a series of slightly water-soluble beta-phosphino alcohols (PTA-CRR'OH, R = C6H5, C(6)H(4)OCH(3), ferrocenyl; R' = H, C(6)H(5), C(6)H(4)OCH(3)) derived from the heterocyclic phosphine PTA. Insertion of CO(2) yielded the highly water-soluble carboxylate PTA-CO(2)Li, S(2)5 degrees approximately 800 g/L. The compounds have been fully characterized in the solid state by X-ray crystallography and in solution by multinuclear NMR spectroscopy. The addition of PTA-Li to symmetric ketones results in a racemic mixture of PTA-CR(2)OH ligands with a single resonance in the (31)P{(1)H} NMR spectrum between -95 and -97 ppm. The addition of PTA-Li to aldehydes results in a mixture of diasteromeric compounds, PTA-CHROH, with two (31)P{(1)H} NMR resonances between -100 and -106 ppm. Three (eta(6)-arene)RuCl(2)(PTA-CRR'OH) complexes of these ligands were synthesized and characterized, with the ligands binding in a kappa1 coordination mode. All the ligands and ruthenium complexes are slightly soluble in water with S25 degrees = 3.9-11.1 g/L for the PTA-CRR'OH ligands and S(25) degrees = 3.3-14.1 g/L for the (eta(6)-arene)RuCl(2)(PTA-CRR'OH) complexes.