Synthesis,Characterization, and Antibacterial Activity of Some Novel Substituted Imidazole Derivatives via One‐pot Three‐Component

A simple and highly efficient one‐pot, three‐component synthesis of novel substituted imidazole derivatives has been reported by the reaction of 3‐(2‐bromoacetyl)‐2H‐chromen‐2‐one, ammonium thiocyanate, and phenacyl aniline in the presence of acetic acid as a solvent under reflux condition with good yields. The structures of newly synthesized compounds were characterized by their analytical and spectral data. One of these compounds 4a showed good antibacterial activity against Escherichia coli gram‐negative strains.     

Synthesis,Structural Characterization,and Biological Evaluation of Novel Substituted 1,3‐Thiazole Derivatives Containing Schiff Bases

In this study, thiazole derivatives containing Schiff bases ( 7a , 7b , 7c , 7d , 7e , 7f , 8a , 8b , 8c , 8d , 8e , 8f , 9a , 9b , 9c , 9d , 9e , 9f ) were synthesized in moderate to high yields (49–94%) using the Hantzsch reaction with thiosemicarbazone derivatives ( 5a , 5b , 5c ) and 2‐bromo‐1‐phenylethanone derivatives ( 6a , 6b , 6c , 6d , 6e , 6f ). The structures of synthesized compounds were elucidated by IR, ¹H NMR, ¹³C NMR, elemental analyses, mass spectroscopy and X‐ray diffraction analysis techniques. Moreover, the synthesized compounds were tested for their in vitro antifungal activity and most of them exhibited moderate to good activity against Fusariumoxysporumf.sp. lycopersici.      

Convenient Synthesis of Highly Substituted Imidazole Derivatives

A one-pot synthesis of the trisubstituted imidazole derivatives from α-acetoxy-α-chloro-β-keto-esters, aldehydes, and ammonium acetate has been developed.     

Synthesis,Characterization, and Biological Evaluation of Some Novel Pyrazolo[5,1-b]thiazole Derivatives as Potential Antimicrobial and Anticancer Agents

The pharmacological activities of thiazole and pyrazole moieties as antimicrobial and anticancer agents have been thoroughly described in many literature reviews. In this study, a convenient synthesis of novel pyrazolo[5,1-b]thiazole-based heterocycles was carried out. The synthesized compounds were characterized by IR, ¹H and ¹³C NMR spectroscopy and mass spectrometry. Some selected examples were screened and evaluated for their antimicrobial and anticancer activities and showed promising results. These products could serve as leading compounds in the future design of new drug molecules.     

Triazole‐Substituted Nitroarene Derivatives: Synthesis,Characterization, and Energetic Studies

A series of dense and energetic polynitroaryl‐1,2,4‐triazoles were synthesized through the nitration of aryl‐1,2,4‐triazoles. The Cu‐catalyzed/base‐mediated coupling reactions of haloarenes with 1,2,4‐triazoles delivered N‐aryl‐1,2,4‐triazoles. These new nitro‐rich‐aryltriazoles were characterized by analytical and spectroscopic methods. The solid‐state structures of most of these compounds were established by X‐ray diffraction analysis. Their thermal properties were determined by differential scanning calorimetry–thermogravimetric analysis. Their heats of formation (HOFs) and crystal densities were also calculated. The densities of the synthesized compounds ranged from 1.40 to 1.85 g cm^?3. Some of these newly synthesized compounds exhibited high positive HOFs, good thermal stabilities, high densities, and reasonable detonation velocities and pressures.     

Synthesis and Applications of 2‐Substituted Imidazole and Its Derivatives: A Review

Imidazole and its derivatives are assigned as an exclusive and multifaceted skeleton because of having a variety of applications in medicinal and synthetic organic chemistry as well as in the field of industrial chemistry. For these perspectives, various elegant methods for imidazoles and its derivatives have been developing over the last years using different types of catalyst to improve selectivity, purity, and yield of the product. Thus, we have reviewed various synthetic routes for the formation of imidazoles and their applications from 2014 to 2016.     

Design,Synthesis, and Biological Evaluation of Some Cyclohepta[b]Thiophene and Substituted Pentahydrocycloheptathieno[2,3‐d]Pyrimidine Derivatives

This investigation describes the design of a series of cycloheptathieno[2,3‐d]pyrimidines along with their synthetic strategy. The target compounds were screened for their PARP‐1 inhibitory activity. The modeling study declared that most of the docked compounds showed the same interactions as 3‐aminobenzamide, where Gly 894, His 862, Tyr 896, Arg 878, and Ser 864 were the main residues involved in hydrogen bond formation. Compounds eliciting the top ranked docking results were screened for their PARP‐1 inhibitory activity giving promising results, and three representative compounds were tested for their cytotoxic activity using Doxorubicin as a reference standard. The target compounds 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 including cyclohepta[b]thiophene and pentahydrocycloheptathieno[2,3‐d]pyrimidine cores were designed, prepared, and tested for their PARP‐1 inhibitory activity. Compounds 16 (R: ―NHC(S)NH2) and 11 (R: ―CS) were the most potent ones.     

Synthesis,Characterization, and Biological Activity of Substituted Thiazole-5-carboxaldehydes and Their Ylidenenitriles Derivatives

The Vilsmeier–Haack reaction of 2-amino -4-(4-substituted phenyl)-thiazoles 1, in the presence of micellar media, gives formylated derivatives 2, which upon hydrolysis afforded thiazole-5-carboxaldehydes 3. Microwave-assisted Knoevenagel condensation of 3 with active methylene compounds, in the presence of piperidine as catalyst, gives excellent yields of ylidenenitrile compounds 4. The structures of the newly synthesized compounds were established on the basis of elemental analysis, IR, ¹H NMR, and ¹³C NMR spectral analysis. All newly synthesized compounds were screened for antibacterial activity using two Gram-positive and one Gram-negative bacterial species and their antifungal activity was screened using two fungal species.     

Synthesis and Biological Evaluation of Some Novel Isoxazole Derivatives

The reaction of 5‐amino‐3‐methylisoxazole ( 1 ) with formalin and secondary amines gave the corresponding Mannich bases 3 , 4 , 5 , 6 . Alkylation of isoxazole derivative 1 with Mannich bases hydrochloride gave unsubstituted isoxazolo[5,4‐b ]pyridine derivatives 8a , 8b via alkylation at position 4. Moreover, coupling reaction of 1 with different diazonium salts gave the corresponding mono and bisazo dyes of isoxazole derivative. The newly synthesized compounds were screened for their antitumor activity compared with 5‐fluorouracil as a well‐known cytotoxic agent using Ehrlich ascites carcinoma cells. Interestingly, the obtained results showed clearly that compounds 3 , 15 , 8b , 4 , 8a , and 5 exhibited high antitumor activity than 5‐fluorouracil.     

Synthesis,Characterization, and Molecular Docking Study of Some Novel Imidazole Derivatives as Potential Antifungal Agents

The azole pharmacophore is still regarded as a viable lead structure for the synthesis of more effective antifungal agents. In this study, two novel series of imidazole derivatives containing dithiocarbamate (5a–5g) and (benz)azolethiol (6a–6n) side chains that are structurally related to the famous antifungal azole pharmacophore were synthesized, and the structures of them were characterized by spectral (IR, ¹H NMR, ¹³C NMR, and MS spectra) analyses. The synthesized compounds were screened in vitro antifungal activity against pathogenic strains fungi. Theoretical ADME (absorption, distribution, metabolism, and excretion) predictions were calculated for final compounds. A molecular docking study of the most active compound with target “lanosterol 14α‐demethylase” (CYP51) was performed to unravel the mode of antifungal action. Compound 5e , which features imidazole and 4‐methoxybenzyl piperazine scaffolds, showed the most promising antifungal activity with an MIC₅₀ value of 0.78 μg/mL against C. krusei. Effect of the compound 5e against ergosterol biosynthesis was observed by LC–MS–MS method, which is based on quantification of ergosterol level in C. krusei.     

取代嘧啶化合物的合成和生物活性研究

合成了14个新型取代嘧啶类化合物,结构经质谱、红外光谱、氢核磁共振光谱和元素分析确证.杀虫、杀菌和除草活性测定结果表明,部分化合物具有良好的杀菌活性.在嘧啶环的2-位上导入二甲氨基时表现出杀菌活性,但在嘧啶环的5-位上有甲基取代基时,杀菌活性下降.在嘧啶的4-位导入苯氧基时,显示出良好的杀菌活性,如化合物3b,3c和3e,苯环上的最优取代基是2-硝基-4-三氟甲基.     

Synthesis,Reactions, Characterization and Biological Evaluation of 2,3′‐Bipyridine Derivatives (III)

1‐Pyridin‐3‐yl‐3‐(2‐thienyl of 2‐furyl)prop‐2‐en‐1‐ones 1a , 1b reacted with 2‐cyanoethanethioamide 2 to afford the corresponding 4‐(thiophen‐2‐yl or furan‐2‐yl)‐6‐sulfanyl‐2,3′‐bipyridine‐5‐carbonitriles 3a , 3b . The synthetic potentiality of compounds 3a , 3b were investigated in the present study via their reactions with several active halogen containing compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 5 , 5a , 5b . Our aim here is the synthesis of 4‐(2‐thienyl or 2‐furyl)‐6‐pyridin‐3‐ylthieno[2,3‐b]pyridin‐3‐amines 6a , 6b , 6c , 6d , 6e , 6g , 6h , 6i , 6j , 6k , 6l , 6m , 6n ,via 6‐(alkyl‐thio)‐4‐(2‐thienyl or 2‐furyl)‐2,3′‐bipyridine‐5‐carbonitriles 5a , 5b , 5c , 5d , 5e , 5i , 5j , 5k , 5l , 5m . The structures of all newly synthesized heterocyclic compounds were elucidated by considering the data of IR, ¹H‐NMR, mass spectra, as well as that of elemental analyses. Anti‐cancer, anti‐Alzheimer, and anti‐COX‐2 activities were investigated for all the newly synthesized heterocyclic compounds.     

Synthesis of Some Novel Pyrazole‐Substituted 9‐Anilinoacridine Derivatives and Evaluation for their Antioxidant and Cytotoxic Activities

This article focuses on the synthesis of new series of pyrazole‐substituted 9‐anilinoacridine derivatives 5a – m and 6a – l . The compounds were confirmed by physical and analytical data. The synthesized compounds when screened for in vitro antioxidant activity showed promising activity for many compounds. The selected compounds were screened for cytotoxic activity showed promising inhibition of HEp‐2 cell line for the compounds 6c , 6e , and 6f .     

Synthesis and Antimicrobial Activity of Some Novel Substituted Bis‐Pyridone,Pyrazole, and Thiazole Derivatives

A variety of novel bis‐heterocyclic derivatives were synthesized via the reaction of bis‐cyanoacetanilide derivative 3 with various aromatic aldehydes (1:2 molar ratio), to give the corresponding bis‐arylidene derivatives 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l , 5m . On the other hand, reacting compound 3 with substituted 2‐hydroxybenzaldehydes 6a , 6b , 6c afforded 2‐iminochromene‐3‐carboxamides 7a , 7b , 7c . The reaction of compound 5 with malononitrile afforded the novel bis‐pyridones 9a , 9b , 9c , 9f , 9g , 9h . The reaction of 5 with hydrazine derivatives afforded pyrazoles 11a , 11b , 11c , 11d , 11e , 11f , respectively. Compound 3 reacts with phenyl isothiocyanate in the presence of potassium hydroxide at room temperature followed by addition of some different halo‐carbonyl compounds to afford bis‐poly‐functionalized thiazole derivatives 13a , 13b , 13c . The bis‐enamine derivative 15 reacts also with hydrazine hydrate, guanidine, and hydroxylamine to give bis‐pyrazole 17 , pyrimidine 19 , and isoxazole 21 derivatives, respectively. Some of the newly synthesized compounds show moderate to high antimicrobial activity.     

Synthesis of Imidazole Derivatives Using 2‐Unsubstituted 1H‐Imidazole 3‐Oxides

The reaction of 1,4,5‐trisubstituted 1H‐imidazole 3‐oxides 1 with Ac₂O in CH₂Cl₂ at 0 – 5° leads to the corresponding 1,3‐dihydro‐2H‐imidazol‐2‐ones 4 in good yields. In refluxing Ac₂O, the N‐oxides 1 are transformed to N‐acetylated 1,3‐dihydro‐2H‐imidazol‐2‐ones 5 . The proposed mechanisms for these reactions are analogous to those for N‐oxides of 6‐membered heterocycles (Scheme 2). A smooth synthesis of 1H‐imidazole‐2‐carbonitriles 2 starting with 1 is achieved by treatment with trimethylsilanecarbonitrile (Me₃SiCN) in CH₂Cl₂ at 0 – 5° (Scheme 3).     

Synthesis and Characterization of Some BODIPY‐based Substituted Salicylaldimine Schiff Bases

Salicylaldimine Schiff bases represent an important class of hetero‐polydentate ligands capable of forming mononuclear, binuclear, and polynuclear complexes with transition and non‐transition metals. In this report, we developed an easy synthesis of BODIPY‐based salicylaldimine Schiff bases and synthesized five new derivatives. These were characterized by elemental analysis, infrared, UV‐Vis, nuclear magnetic resonance spectroscopy, and X‐ray crystallography. Finally, one of the Schiff bases was reacted with BF₃·OEt₂ to synthesize corresponding bis‐BF₂ boron complex. The photophysical and electrochemical properties of the Schiff bases and the boron complex were evaluated and rationalized by theoretical calculations. The bis‐BF₂ boron complex showed excited state charge redistribution, thus could be useful as sensitizers for designing new dye‐sensitized solar cells.     

Synthesis and Characterization of Organosilicon Substituted Fluorenyl Derivatives

Friedel‐Crafts cycloalkylation of biphenyl with 2,3‐dichlorobutyltrichlorosilane(Cl₃Si‐CH₂CHClCHClCH₃) at a temperature of 100°C in the presence of anhydrous aluminum chloride catalyst gave cyclized product, 9‐methyl‐9‐(2‐trichlorosilylethyl)fluorene 1a , in 33% yield. Methylation of 1a with nucleophilic reagent such as methyl magnesium chloride, gave 9‐methyl‐9‐(2‐trimethylsilylethyl)fluorene 2 while bromination of 2 with excess amount of bromine in DMF resulted in 2,7‐dibromo‐9‐methyl‐9‐(2‐trichlorosilyl)fluorene 3 in good yield. All the compounds were structurally identified by GC/MS, ¹H and ¹³C‐NMR spectroscopy.     

Design,Synthesis and Molecular Modeling of Nonsteroidal Anti‐inflammatory Drugs Tagged Substituted 1,2,3‐Triazole Derivatives and Evaluation of Their Biological Activities

A novel series of 1,4‐disubstituted‐1,2,3‐triazole derivatives 3a – l and 5a – i were one‐pot synthesized via CuAAC‐alkyne click chemistry and evaluated for their antibacterial activity against four organisms and screened for their anticancer activity against human colon cancer cell line HT‐29 and human lung cancer cell line HTB‐29. These hybrid molecules structure elucidation has been performed by IR, ¹H‐NMR, ¹³C‐NMR, and mass spectral analysis. Synthesized nonsteroidal anti‐inflammatory drugs‐triazoles evaluated for their antibacterial activities against bacterial microorganisms Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Klebsiella pneumonia. Final compounds 3i , 3c , and 5b showed magnificent broad spectrum activity against P. aeruginosa, K. pneumonia, E. coli, and S. aureus with zone of inhibition values of 20, 15, 17, and 16 mm, respectively. Among the series of compound, 3j showed the best antibacterial activity against all the strains. Further, the compounds 3i and 5a were more cytotoxic than cisplatin against all tested two human cancer cell lines, with 50.8%, and 52.3% and 73.4% and 75.3% of growth, respectively. The synthesized compounds were tested for kinase inhibitory activity against glycogen synthase kinase‐3 protein kinases, in addition, for cytotoxic activity against two different human cancer cell lines.     

Synthesis of Triptycene‐Substituted Azapentacene and Azahexacene Derivatives

We describe the synthesis and characterization of novel iptycene‐substituted azaacenes by using either a classic condensation route (diamine plus ortho‐quinone) and/or a Pd‐catalyzed coupling of an aromatic diamine with an aromatic dihalide. The attachment of an iptycene unit leads to a significant blueshift (15 nm) in the UV/Vis spectra of these azaacenes. The iptycene unit stabilizes a hexaazahexacene with a λ_{max abs} of 833 nm. By employing 5,6‐diamino(benzothiadiazole) as a synthon for tetraaminobenzene, we could prepare the symmetrical bis‐triptycene‐substituted tetraazapentacene in high yields.