Thiazole Analogues of the Marine Alkaloid Nortopsentin as Inhibitors of Bacterial Biofilm Formation

Anti-virulence strategy is currently considered a promising approach to overcome the global threat of the antibiotic resistance. Among different bacterial virulence factors, the biofilm formation is recognized as one of the most relevant. Considering the high and growing percentage of multi-drug resistant infections that are biofilm-mediated, new therapeutic agents capable of counteracting the formation of biofilms are urgently required. In this scenario, a new series of 18 thiazole derivatives was efficiently synthesized and evaluated for its ability to inhibit biofilm formation against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923 and S. aureus ATCC 6538 and the Gram-negative strain Pseudomonas aeruginosa ATCC 15442. Most of the new compounds showed a marked selectivity against the Gram-positive strains. Remarkably, five compounds exhibited BIC₅₀ values against S. aureus ATCC 25923 ranging from 1.0 to 9.1 µM. The new compounds, affecting the biofilm formation without any interference on microbial growth, can be considered promising lead compounds for the development of a new class of anti-virulence agents.     

Solventless Mechanosynthesis Of Bis(Indolyl)Methanes

Ball-milling technique as a solvent-free and an alternative green process was investigated for the eco-benign synthesis of bis(indolyl)methanes (BIMs) from various aldehydes and selected ketones with indoles in high yields. The present methodology has several advantages such as simple procedure, good yields, mild conditions, and reduced environmental consequences. The silica gel acts both as a grinding medium and an acid catalyst. The utility of this technique was demonstrated by synthesizing library of 17 BIMs including two natural products trisindoline and tris(1H-indol-3-yl)methane.     

Synthesis of Bis(indolyl) Methanes in Catalyst- and Solvent-Free Reaction

Efficient synthesis of bis(indolyl) methanes by the reaction of indoles with various carbonyl compounds in the absence of catalyst and solvent afforded the corresponding bis(indolyl) methanes in excellent yields.     

NaBF4催化合成二吲哚甲烷类化合物

在乙醇水溶液中,以Na BF4为催化剂,通过吲哚与芳香醛间的串联反应合成了二吲哚甲烷衍生物。考察了催化剂种类、反应介质、温度、反应时间等因素对反应的影响,在优化条件下以较高产率得到了一系列目标产物。     

Highly Efficient Synthesis of Bis（indolyl）methanes Catalyzed by Sodium Tetrafluoroborate

Sodium tetrafluoroborate （NaBF4） was found to catalyze the electrophilic substitution reactions of indoles with aldehydes and ketones under solvent-free conditions to afford the corresponding bis（indolyl）methanes in high yields.     

二(o-溴苄基)锡双(二乙基二硫代氨基甲酸)酯和二(o-氯苄基)锡双(吡咯啶二硫代氨基甲酸)酯的合成、结构及体外抗癌活性研究

二(o-溴苄基)二溴化锡和二(o-氯苄基)二氯化锡分别与N,N-二乙基二硫代氨基甲酸钠和吡咯啶二硫代氨基甲酸钠反应,合成了二(o-溴苄基)锡双(二乙基二硫代氨基甲酸)酯(1)和二(o-氯苄基)锡双(吡咯啶二硫代氨基甲酸)酯(2)。用X-射线单晶衍射测定了两个化合物的晶体结构,测试结果表明:化合物1的晶体为单斜晶系,空间群P21/c,晶体学参数a=1.827 36(4)nm,b=0.900 60(2)nm,c=1.988 41(5)nm,β=114.878 0(10)°,V=2.968 71(12)nm3,Z=4,Dc=1.690 g·cm-3,μ(Mo Kα)=38.50 cm-1,F(000)=1 496,R1=0.051 6,wR2=0.154 6。化合物2的晶体为单斜晶系,空间群C2/c,晶体学参数a=2.241 28(4)nm,b=0.818 78(2)nm,c=1.542 69(3)nm,β=106.787 0(10)°,V=2.710 37(10)nm3,Z=4,Dc=1.623 g·cm-3,μ(Mo Kα)=14.65 cm-1,F(000)=1 336,R1=0.022 9,wR2=0.056 5。晶体中锡原子呈六配位畸变八面体构型。对其结构进行量子化学从头计算,探讨了配合物的稳定性、分子轨道能量以及部分前沿分子轨道的组成特征。测定了配合物的热稳定性和体外抗癌活性。     

In Vitro Anticancer Screening,Molecular Docking and Antimicrobial Studies of Triazole-Based Nickel(II) Metal Complexes

Herein we describe the synthesis of a series of nickel(II) complexes (C1–C3) with Schiff bases (HL1–HL3) derived from 4-amino-5-mercapto-3-methyl-1,2,4-triazole and ortho/meta/para-nitrobenzaldehyde having composition [Ni(L)₂(H₂O)₂]. The obtained ligands and their complexes were characterized using physico-chemical techniques viz., elemental analysis, magnetic moment study, spectral (electronic, FT-IR, 1H-NMR) and thermal analysis. The elemental analysis and spectral analysis revealed that Schiff bases behave as monoanionic bidentate ligands towards the Ni(II) ion. Whereas, the magnetic moment study suggested the octahedral geometry of all the Ni(II) complexes. The thermal behavior of the complexes has been studied by thermogravimetric analysis and agrees well with the composition of complexes. Further, the biological activities such as antimicrobial and antifungal studies of the Schiff bases and Ni(II) complexes have been screened against bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa) and fungal species (Aspergillus niger and Candida albicans) activity by MIC method, the results of which revealed that metal complexes exhibited significant antimicrobial activities than their respective ligands against the tested microbial species. Furthermore, the molecular docking technique was employed to investigate the active sites of the selected protein, which indeed helped us to screen the potential anticancer agents among the synthesized ligand and complexes. Further, these compounds have been screened for their in vitro anticancer activity using OVCAR-3 cell line. The results revealed that the complexes are more active than the ligands.     

Antimony Trichloride Catalyzed Condensation of Indole and Carbonyl Compounds: Synthesis of Bis(indolyl)methanes

A mild and efficient condensation reaction of indoles with various aldehydes and ketones under catalysis of antimony trichloride (SbCl₃) afforded biologically important bis(indolyl)methanes in good yield. The structures of all the newly synthesized compounds were elucidated on the basis of IR, ¹H NMR and mass spectral data.     

蒙脱土负载碘催化合成双吲哚甲烷衍生物

以蒙脱土负载碘(MMT/I2)作催化剂,醛(1a~1g)与吲哚(2)反应合成双吲哚甲烷衍生物(3a~3g),其结构经1H NMR和IR确证。以3a的合成为例,研究了催化剂、溶剂、反应时间、温度和物料比r[n(1)∶n(2)]对3产率的影响。结果表明:在最佳合成条件(2 1 mmol,r=1.1∶2.0,10 mol%MMT/I2,乙腈1 m L,于25℃反应5min)下,3a~3g产率67.9%~96.2%。MMT/I2循环使用3次,3a产率78.6%。     

Zeolite Catalyzed Synthesis of bis (Indolyl) Methanes

Abstract

HY-Zeolite is found to be a versatile catalyst for the electrophilic substitution reaction of indoles with carbonyl compounds to afford the corresponding bis(indolyl) methanes in good yields.     

Efficient Synthesis of 2-Aminopyridine Derivatives: Antibacterial Activity Assessment and Molecular Docking Studies

A new and suitable multicomponent one-pot reaction was developed for the synthesis of 2-amino-3-cyanopyridine derivatives. Background: This synthesis was demonstrated by the efficient and easy access to a variety of substituted 2-aminopyridines using enaminones as key precursors under solvent-free conditions. Methods: A range of spectroscopic techniques was used to determine and confirm the chemical structures (FTIR, ¹H NMR, ¹³C NMR). The antimicrobial potency of synthesized compounds (2a–d) was tested using disk diffusion assays, and the Minimum Inhibitory Concentration (MIC) for the active compounds was determined against a panel of microorganisms, including Gram-positive and Gram-negative bacteria and yeasts. Moreover, a docking analysis was conducted by Molecular Operating Environment (MOE) software to provide supplementary information about the potential, as well as an ADME-T prediction to describe the pharmacokinetic properties of the best compound and its toxicity. Results: The results of the antimicrobial activity indicated that compound 2c showed the highest activity against Gram-positive bacteria, particularly S. aureus and B. subtilis whose MIC values were 0.039 ± 0.000 µg·mL⁻¹. The results of the theoretical study of compound 2c were in line with the experimental data and exhibited excellent antibacterial potential. Conclusions: On the basis of the obtained results, compound 2c can be used as an antibacterial agent model with high antibacterial potency.     

Convenient Synthesis of Bis(indol)alkanes by Niobium(V) Chloride

Bis(indolyl)alkanes have been synthesized in excellent yields in the presence of a catalytic amount of niobium(V) chloride under solvent-free conditions.     

Synthesis of Pharmacologically Active Bis(indolyl) and Tris(indolyl) Derivatives Using Chlorotrimethylsilane

Chlorotrimethylsilane is found to be a comparatively fast and efficient catalyst for carrying out electrophilic substitution reactions of indoles with various aldehydes/ketones/triethylorthoformate, yielding excellent amount of bis(indolyl)methanes/tris(indolyl)methanes. The merits of this protocol are avoidance of any external energy source, minimal reaction time, simple and easy procedure and high yield under solvent free room temperature condition. The versatility of this method has been tested with various aldehydes/ketones and received satisfactory results.     

Synthesis,Molecular Docking Studies,and Anticonvulsant Evaluation of Novel bis‐Phenylhydrazones against Chemically induced Seizures in Mice

A series of novel bis‐phenylhydrazones were synthesized by the condensation of dialdehydes with phenylhydrazine to evaluate them for their anticonvulsant activity. Efficacy of newly synthesized compounds against pentylenetetrazole (PTZ )‐induced, strychnine‐induced, and picrotoxin‐induced convulsions was tested after administration of these compounds to albino mice via the oral route. All the five tested compounds showed anticonvulsant activity against strychnine‐induced and picrotoxin‐induced convulsions in a dose‐dependent manner. However, the effect was more significant against PTZ ‐induced convulsions. Behavioral pattern studies on mice suggested that these compounds are less neurotoxic compared to phenytoin. Molecular docking studies were carried out to correlate the experimental and theoretical results. It was concluded that these compounds exerted their anticonvulsant effect through the modification of the function of GABA receptor‐mediated chloride channels. Molecular docking studies revealed a good correlation, which indicated that in silico studies could provide an alternate tool for the identification and design of more potent anticonvulsant agents.     

二(o-溴苄基)锡双(二乙基二硫代氨基甲酸)酯和二(o-氯苄基)锡双(吡咯啶二硫代氨基甲酸)酯的合成、结构及体外抗癌活性研究

二（o-溴苄基）二溴化锡和二（o-氯苄基）二氯化锡分别与N,N-二乙基二硫代氨基甲酸钠和吡咯啶二硫代氨基甲酸钠反应,合成了二（o-溴苄基）锡双（二乙基二硫代氨基甲酸）酯（1）和二（o-氯苄基）锡双（吡咯啶二硫代氨基甲酸）酯（2）。用X-射线单晶衍射测定了两个化合物的晶体结构,测试结果表明：化合物1的晶体为单斜晶系,空间群P2₁/c,晶体学参数a=1.82736（4）nm,b=0.90060（2）nm,c=1.98841（5）nm,β=114.8780（10）°,V=2.96871（12）nm³,Z=4,D_c=1.690g·cm^-3,μ（MoKα）=38.50cm^-1,F（000）=1496,R₁=0.0516,wR₂=0.1546。化合物2的晶体为单斜晶系,空间群C2/c,晶体学参数a=2.24128（4）nm,b=0.81878（2）nm,c=1.54269（3）nm,β=106.7870（10）°,V=2.71037（10）nm³,Z=4,D_c=1.623g·cm^-3,μ（MoKα）=14.65cm^-1,F（000）=1336,R₁=0.0229,wR₂=0.0565。晶体中锡原子呈六配位畸变八面体构型。对其结构进行量子化学从头计算,探讨了配合物的稳定性、分子轨道能量以及部分前沿分子轨道的组成特征。测定了配合物的热稳定性和体外抗癌活性。     

Facile One-Pot Multicomponent Synthesis of Pyrazolo-Thiazole Substituted Pyridines with Potential Anti-Proliferative Activity: Synthesis,In Vitro and In Silico Studies

Pyrazolothiazole-substituted pyridine conjugates are an important class of heterocyclic compounds with an extensive variety of potential applications in the medicinal and pharmacological arenas. Therefore, herein, we describe an efficient and facile approach for the synthesis of novel pyrazolo-thiazolo-pyridine conjugate 4, via multicomponent condensation. The latter compound was utilized as a base for the synthesis of two series of 15 novel pyrazolothiazole-based pyridine conjugates (5–16). The newly synthesized compounds were fully characterized using several spectroscopic methods (IR, NMR and MS) and elemental analyses. The anti-proliferative impact of the new synthesized compounds 5–13 and 16 was in vitro appraised towards three human cancer cell lines: human cervix (HeLa), human lung (NCI-H460) and human prostate (PC-3). Our outcomes regarding the anti-proliferative activities disclosed that all the tested compounds exhibited cytotoxic potential towards all the tested cell lines with IC₅₀ = 17.50–61.05 µM, especially the naphthyridine derivative 7, which exhibited the most cytotoxic potential towards the tested cell lines (IC₅₀ = 14.62–17.50 µM) compared with the etoposide (IC50 = 13.34–17.15 µM). Moreover, an in silico docking simulation study was performed on the newly prepared compounds within topoisomerase II (3QX3), to suggest the binding mode of these compounds as anticancer candidates. The in silico docking results indicate that compound 7 was a promising lead anticancer compound which possesses high binding affinity toward topoisomerase II (3QX3) protein.     

Structure and Photosynthetic Mimicking of Bis(2,6-bis(benzimidazol-2-yl)pyridine)manganese(II)

Introduction　　Manganeseionsplayanimportantroleinthelight in ducedoxidationofwatertomolecularoxygeninphotosys temII (PSII)ofgreenplants.1 3Inrecentyears ,man ganesecomplexesofpolypyridineligands ,suchasbipyri dine ,1,10 phenanthrolineand 2 ,2′:6′,2″ terpyridine ,havehadconsiderableattentionasthecomplexesformedareusefulmodelsformanganese containingbimolecu lars .4 6 Therefore ,synthesisandcharacterizationofman ganeseinitsvariousoxidationstates ,withvariousligandtypesandnuclearities ,hav…     

4,5,6-三取代嘧啶苯磺酰脲类化合物的生物活性、分子对接与3D-QSAR关系研究

用柔性分子对接方法(FlexX)将15个4,5,6-三取代嘧啶苯磺酰脲化合物以及3个不含5-位取代嘧啶苯磺酰脲化合物(分别为4,6-双取代嘧啶和4-取代嘧啶)和乙酰羟酸合成酶(AHAS)活性口袋进行了对接, 对接程序预测的抑制剂和酶之间的相互作用能与抑制活性之间有一定的相关性, 相关系数为0.660. 然后采用比较分子相似性指数分析(CoMSIA)对27个新型4,5,6-三取代嘧啶苯磺酰脲类化合物的除草活性进行三维定量构效关系(3D-QSAR)研究. 建立了三维定量构效关系CoMSIA模型, 立体场、静电场和氢键的贡献分别为47.3%, 32.8%, 19.9%. 交叉验证系数q2值为0.520. 根据CoMSIA模型的立体场、静电场、氢键给体场三维等值线图不仅直观地解释了结构与活性的关系, 并且与用FlexX预测的结合模式相一致, 证明了我们预测的结合模式是可靠的, 为进一步设计高活性的标题化合物提供较好的理论指导.