Synthesis,Characterization and Biological Evaluation of New 3,5-Disubstituted-Pyrazoline Derivatives as Potential Anti-Mycobacterium tuberculosis H37Ra Compounds

A total of fourteen pyrazoline derivatives were synthesized through cyclo-condensation reactions by chalcone derivatives with different types of semicarbazide. These compounds were characterized by IR, 1D-NMR (¹H, ¹³C and Distortionless Enhancement by Polarization Transfer - DEPT-135) and 2D-NMR (COSY, HSQC and HMBC) as well as mass spectroscopy analysis (HRMS). The synthesized compounds were tested for their antituberculosis activity against Mycobacterium tuberculosis H37Ra in vitro. Based on this activity, compound 4a showed the most potent inhibitory activity, with a minimum inhibitory concentration (MIC) value of 17 μM. In addition, six other synthesized compounds, 5a and 5c–5g, exhibited moderate activity, with MIC ranges between 60 μM to 140 μM. Compound 4a showed good bactericidal activity with a minimum bactericidal concentration (MBC) value of 34 μM against Mycobacterium tuberculosis H37Ra. Molecular docking studies for compound 4a on alpha-sterol demethylase was done to understand and explore ligand–receptor interactions, and to hypothesize potential refinements for the compound.     

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.     

Synthesis,antibacterial, and antioxidant activities of naphthyl-linked disubstituted 1,2,3-triazoles

Here, click synthesis of 15 naphthyl-linked disubstituted 1,2,3-triazoles has been carried out by the reaction between 1-(prop-2-yn-1-yloxy)naphthalene and aromatic azides. The structure elucidation of the synthesized compounds was carried out by FTIR, ¹H NMR, ¹³C NMR, and HRMS techniques. Further, the compound 7f was confirmed by X-ray crystallography (CCDC 1876891). The synthesized compounds were explored for antibacterial activity against Bacillus cereus, Escherichia coli, and Staphylococcus aureus. Biological evaluation of synthesized 1,2,3-triazoles revealed moderate to good antibacterial activity against the tested strains. The antioxidative behavior of synthesized compounds manifested the remarkable free radical scavenging activity using DPPH assay.     

Synthesis,spectral characterization and inhibitory potency of ferrocene‐containing mannosides towards type 1 fimbriated Escherichia coli

Escherichia coli adhesion to the bladder epithelium is mediated through recognition of the tissue‐surface mannosylated proteins with bacterial lectin FimH. The inhibition of this recognition‐dependent interaction has been recognized as a promising strategy for the development of an anti‐adhesion therapy. Mannosides with either aryl‐ or elongated alkyl‐functionalized aglycon portions have been shown to be potent inhibitors of FimH‐mediated adhesion. Thus, we have synthesized four mannose‐based bioorganometallics containing an extended alkyl chain between sugar and ferrocene components connected via ester linkage ( 14 (n = 4) and 15 (n = 5)) or amide linkage ( 18 (n = 3) and 19 (n = 4)). The novel bioconjugates were characterized using infrared and NMR (¹H, ¹³C, COSY, NOESY, HSQC, HMBC) spectroscopies, electrospray ionization mass spectrometry and high‐resolution mass spectrometry. Hemagglutination inhibitory assay of the novel bioorganometallics revealed an enhanced inhibitory potential in comparison to methyl α‐d ‐mannoside. Thereby, the bioconjugate 19 exhibited a twofold increase in inhibitory activity compared with 14 , 15 and 18 . Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis,Crystal Structures,Fluorescence and Xanthine Oxidase Inhibitory of Sulfur-Containing Pyrazole Derivatives Incorporated with Oxadiazole and Triazole

Some sulfur-containing pyrazole derivatives incorporated with 1,3,4-oxadiazole and 1,2,4-triazole were designed and synthesized. All the compounds were fully characterized by IR, ¹H NMR, ¹³C NMR and elemental analyses. Two crystal structures were determined by single crystal X-ray diffraction analyses. The fluorescence properties were investigated in DMSO solution. In addition, the in vitro xanthine oxidase (XO) inhibitory activity were evaluated, and the results showed that one compound displayed moderate XO inhibitory activity.     

A spectral study of 2-formylimidazole 4N-substituted thiosemicarbazones and their copper(II) complexes

Copper(II) complexes of 2-formylimidazole ⁴N-methyl-, ⁴N-dimethyl- ⁴N-ethyl- and 3-hexa-methyleneiminylthiosemicarbazone, along with two nickel(II) complexes of the latter thiosemicarbazone, have been synthesized. Infrared, electronic, NMR and ESR spectra have been used to characterize the complexes and the uncomplexed thiosemicarbazones. None of the complexes or thiosemicarbazones possess growth inhibitory activity against Aspergillus niger and Paecilomyces variotii.     

Synthesis and biological activity of fluorinated 2-amino-4-aryl-3,4-dihydro[1,3,5]triazino[1,2-a]benzimidazoles

The heterocyclic nucleus s-triazino[1,2-a]benzimidazole has been reported to exhibit antibacterial activity. In this study, seven new 3,4-dihydro[1,3,5]triazino[1,2-a]benzimidazole derivatives were prepared via cyclocondensation between 2-guanidinobenzimidazole and fluorine substituted (including trifluoromethyl) benzaldehydes. The structures of all the compounds were confirmed by ¹H, ¹³C NMR and IR spectral data. Spectral data also suggested the existence of various tautomeric forms of the fluorine-containing s-triazino[1,2-a]benzimidazole compounds. The synthesized compounds were also screened for antibacterial and bovine dihydrofolate reductase (DHFR) inhibitory activities. The compound 3g substituted with a 3′,5′-bis(trifluoromethyl)phenyl moiety demonstrated the best antibacterial activity in the series. None of the tested compounds significantly inhibited bovine DHFR.     

Synthesis and fungicidal activity of aryl(arylamino)methylphosphonic acids

A series of aryl(arylamino)methylphosphonic acids were synthesized based on the previous work for the modification of alkylphosphonates. As key intermediates, α-aminophosphonates were synthesized with high yield by a three-component Kabachnik–Fields reaction under solvent-free conditions. The compounds were identified and characterized by infrared, ¹H NMR, ¹³C NMR, mass spectrum, and elemental analyses. Their fungicidal activities against typical fungi occurring in the Chinese agro-ecosystems were evaluated. The results of preliminary bioassays showed that some of the title compounds exhibited moderate fungicidal activities against tomato late blight and cucumber fusarium wilt. For example, compound 3b showed 78% inhibitory activity against tomato late blight, and compound 3h possessed 86% inhibitory activity against cucumber fusarium wilt.     

Synthesis and biological activities of hydroxyl-protected fluorine-containing 4,4-dihydroxylmethyl-2-aryl-iminothiazolidines

Eight novel compounds were synthesized by a facile and mild method with high yields, and the structures of all the compounds were characterized by ¹H NMR IR mass and high resolution mass spectroscopy. Their inhibitory activity against insect-flight and trehalase in vitro were screened. Some target compounds have moderate inhibitory activity against trehalase, and show inhibition action to insect-flight.     

Synthesis and structure elucidation of five new conjugates of oleanolic acid derivatives and chalcones using 1D and 2D NMR spectroscopy

Five new conjugates of oleanolic acid derivatives and chalcones have been designed and synthesized. The structure elucidation of these conjugates was accomplished by using extensive 1D (¹H, ¹³C) and 2D NMR spectroscopic studies (COSY, HSQC and HMBC); and α‐glucosidase inhibitory activity is reported for these conjugates. Compound 2b (IC₅₀ = 47.5 µm ) displayed much stronger activity than oleanolic acid and acarbose. Copyright © 2012 John Wiley & Sons, Ltd.     

硫代氢化脲嘧啶的合成及其对Hill反应的抑制活性

为了寻找高活性的Hill反应抑制剂, 以β-氨基丙酸为原料, 经过四步反应, 合成了一系列未经文献报道的3-取代硫代氢化脲嘧啶. 所有新化合物的结构均经过¹H NMR, IR和元素分析证. 初步的生物活性测试表明, 所合成的化合物能有效地抑制Hill反应, 如化合物 5j 有很高的抑制活性(IC₅₀＝0.82 g•mL^－1).     

Synthesis and Characterization of Some Heteroaromatic Derivatives of 3‐But‐2‐enoyl‐chromen‐2‐one and Their Potential as Anti‐inflammatory Agents

A novel series of chromen‐2‐ones containing pyrazole, isoxazole, oxazine, and thiazine substitutions have been synthesized by reacting 3‐[3‐(4‐chloro‐phenyl)‐acryloyl]‐chromen‐2‐one and 3‐[3‐(3‐methoxy‐phenyl)‐acryloyl]‐chromen‐2‐one with various cyclizing agents such as hydrazine, phenylhydrazine, urea, and thiourea. The structures of all the synthesized compounds were confirmed by the use of IR, ¹H‐NMR, mass spectroscopy, and elemental analysis data. All the newly synthesized compounds were evaluated for their anti‐inflammatory activity at a dose of 100 mg/kg body weight in carrageenan‐induced rat paw edema model. The entire series of the compounds exhibited moderate to good anti‐inflammatory activity, with the percentage inhibition of edema formation ranging from 39.99 to 63.15 against the reference drug ibuprofen (100 mg/kg) that showed 78.96% inhibition at the third hour. Compounds 3a , 3c , and 3d showed good inhibitory activity, whereas compounds 3b , 3e , 3f , and 3j showed moderate inhibitory activity at the third hour.     

Synthesis,Characterization, and Biological Evaluation of Novel 3‐(4‐Chlorophenyl)‐2‐(substituted)quinazolin‐4(3H)‐one Derivatives as Multi‐target Anti‐inflammatory Agents

A novel class of 3‐(4‐chlorophenyl)‐2‐(substituted)quinazolin‐4(3H)‐one derivatives were synthesized, and the structure of synthesized compounds was characterized by IR, ¹H NMR, and mass spectroscopy. The newly synthesized compounds ( 4a–g and 6a–g ) were tested for their in vitro cyclooxygenase (COX) inhibition activity. The compounds have inhibitory profile against both COX‐1 and COX‐2, and some of the compounds are found to be selective against COX‐2. The compound 6g showed distinct inhibitory activity on COXs. The synthesized compounds were evaluated for their potential anti‐inflammatory activity as inhibitors of the proinflammatory cytokines IL‐6. Compounds 4d – g showed the highest level of inhibition among all the tested compounds. Thus, our data suggested that these compounds may represent a new class of potent anti‐inflammatory agents.     

Synthesis of C12-Keto Saxitoxin Derivatives with Unusual Inhibitory Activity Against Voltage-Gated Sodium Channels

A novel series of C12-keto-type saxitoxin (STX) derivatives bearing an unusual nonhydrated form of the ketone at C12 has been synthesized, and their Na_V-inhibitory activity has been evaluated in a cell-based assay as well as whole-cell patch-clamp recording. Among these compounds, 11-benzylidene STX ( 3 a ) showed potent inhibitory activity against neuroblastoma Neuro 2A in both cell-based and electrophysiological analyses, with EC₅₀ and IC₅₀ values of 8.5 and 30.7 nm , respectively. Interestingly, the compound showed potent inhibitory activity against tetrodotoxin-resistant subtype of Na_V1.5, with an IC₅₀ value of 94.1 nm . Derivatives 3 a – d and 3 f showed low recovery rates from Na_V1.2 subtype (ca 45–79 %) compared to natural dcSTX ( 2 ), strongly suggesting an irreversible mode of interaction. We propose an interaction model for the C12-keto derivatives with Na_V in which the enone moiety in the STX derivatives 3 works as Michael acceptor for the carboxylate of Asp¹⁷¹⁷.     

Effect of the topology on the antibacterial activity of cationic polythioether synthesized by all-click chemistry

Cationic compounds often serve as antibacterial materials for a wide range of applications. However, the relationship of topology−antibacterial activity has been rarely revealed. Herein, three cationic polythioethers (CPTEs) with hyperbranched topologies are well designed and facilely synthesized via an all-click chemistry strategy (including thiol-ene and epoxy-amine additions). These as-prepared CPTEs were found to exhibited outstanding antibacterial activity against Escherichia coli and Staphylococcus aureus with minimum inhibitory concentrations against E. coli of 7.3, 14.6, and 14.6 μg ml⁻¹, and against S. aureus of 14.6, 29.2, and 29.2 μg ml⁻¹, respectively. The antibacterial activity is coincident with their degree of branching (DB, their DB values of 0.81, 0.48, and 0.27), which is mainly attributed to the inherent three-dimensional structure. The present strategy reveals the relationship of polymer topology and antibacterial activity, providing a novel possibility for designing and/or synthesis of high-efficiency antibacterial agents.     

Synthesis,Structure Elucidation and H+/K+‐ATPase Inhibitory Activity of Bisabolangelone Reduction Derivatives

Nine bisabolangelone reduction derivatives were synthesized and separated as potential anti‐ulcer agent. Their structures were characterized by 2D NMR, IR, ESI‐MS, elemental analysis and single‐crystal X‐ray diffraction analysis. Preliminarily H⁺/K⁺‐ATPase activity evaluation indicated that all the target compounds had a certain inhibitory effect, and compounds II and IV exhibited the better inhibitory activity against H⁺/K⁺‐ATPase than bisabolangelone and the commercial omeprazole with the IC₅₀ of 23.21 and 65.32 μmol/L, respectively. The initial structure‐activity analysis suggested that the presence of carbonyl group in six‐membered ring and double bond in side‐chain seemed to be necessary to the activity.     

Antioxidant activity of 5,8-dihydroxy-1,4-dihydro-1,4-methanonaphthalene

5,8-dihydroxy-1,4-dihydro-1,4-methanonaphthalene (DDMN), a substituted phenol, is synthesized by reduction of a cyclic dione, 1,4,4a,8a-tetrahydro-endo-1,4-methano-naphtha-5,8-dione (THMND). Pulse radiolysis technique has been employed to understand the nature of transient species formed on reaction of radiolytic species of water radiolysis with DDMN.^•OH radicals were observed to react with DDMN with a bimolecular rate constant of 1.5×10¹⁰ dm³ mol⁻¹ s⁻¹. Inhibition of radiation induced lipid-peroxidation by DDMN was studied in rat liver microsomes by assessing the formation of thiobarbituric acid reactive substances (TBARS). It was found to be strongly inhibitory. The results suggest that DDMN has very good antioxidant activity and may possibly emerge as a good radio-protector.     

Synthesis and biological evaluation of new oxime-ether derivatives of steroid as anti-bacterial agents

Various oxime-ether derivatives of cholesterol have been synthesized by the alkylation of the steroidal oxime with 1-(2-chloroethyl) pyrrolidine hydrogen chloride/chloroethylamine hydrochloride in the presence of sodium methoxide in dry methanol. The structures of these compounds were elucidated by IR ¹H NMR, FAB mass spectroscopic methods and elemental analyses. The anti-bacterial activity was first tested in vitro by the disk diffusion method against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) of compounds were determined. The results showed that the chloro derivatives exhibited better anti-bacterial activity than the standard drug chloramphenicol.     

Design,Synthesis, and Bioassay of Novel Compounds of Isolongifolenone Oxime Derivatives

A succession of new isolongifolenone oxime derivatives have been designed and synthesized. The structures of these compounds were identified by IR, ¹H‐NMR, ¹³C‐NMR, mass spectra, and elemental analysis. The bioassays of antibacterial, antifungal, and insecticidal activity were carried out. The in vitro antibacterial and antifungal activities were evaluated by the disk diffusion method, and the minimum inhibitory concentration was determined by the microdilution method, while the insecticidal activity was tested by the spraying method or the straw impregnation method. The results of bioassays showed that compound 3f was more active in resisting all the tested bacterial and fungal organisms when compared to the standard drug amoxicillin at the lowest concentration of 31.3 μg/ml. Compound 4 , synthesized by Beckmann rearrangement reaction of isolongifone oxime, exerted moderate insecticidal activity against soybean aphid. Furthermore, compound 3m exhibited more activity in killing armyworms than the standard drug flucycloxuron at the concentration of 0.5 mg/l.