Synthesis,Dissociation Constants,and Antimicrobial Activity of Novel 2,3‐Disubstituted‐1,3‐thiazolidin‐4‐one Derivatives

In this article, a new series of 2,3‐disubstituted‐1,3‐thiazolidin‐4‐one derivatives have been designed, synthesized, and evaluated as antimicrobial agents. New compounds were prepared by the cyclization reaction of N‐substituted carboxylic acid hydrazide derivatives with mercaptoacetic acid. The structures of the obtained compounds were confirmed by means of IR, ¹H NMR, and ¹³C NMR spectra. The dissociation constants were determined using spectrophotometric method. All synthesized compounds were tested for their in vitro antibacterial and antifungal activities using the broth microdilution method.     

A Convenient Synthesis and Biological Research of Novel 5,6,7,8‐Tetrahydro‐1,6‐naphthyridin‐2(1H)‐one Derivatives Hydrochloride as Cytotoxic Agents

A series of 5,6,7,8‐tetrahydro‐1,6‐naphthyridin‐2(1H)‐one derivatives hydrochloride were obtained using a convenient and mild method from 4‐piperidone monohydrate hydrochloride. The newly synthesized compounds and their derivatives were characterized by ¹H NMR, ¹³C NMR, and high‐resolution mass spectrometry. Furthermore, cytotoxicity in vitro of the synthesized compounds were screened using MTT or CCK8 assay. The results showed that some of the compounds showed potential antitumor activity. Among of them, compound 10a had effects against tumor cells (MOLM‐13), and the half maximal inhibitory concentration value was 76 μmol/L.     

Synthesis and Biological Activity of 3‐Methyl‐1H‐pyrazole‐4‐carboxylic Ester Derivatives

In search of novel pyrazole derivatives with bioactivity, a series of 3‐methyl‐1H‐pyrazole‐4‐caboxylic: ester derivatives were synthesized via α‐oxoketene dithioacetals as starting material. The structures of all compounds prepared were confirmed by ^lH NMR, IR, MS and elemental analyses. Preliminary bioassays indicated that some compounds showed fungicidal activity against wheat rust, phoma asparagi and antiviral activity against TMV.     

Synthesis and in vitro Antibacterial Activities of 5‐(2,3,4,5‐Tetrahydro‐1H‐chromeno[2,3‐d]pyrimidin‐5‐yl)pyrimidione Derivatives

A series of novel 5‐(2,3,4,5‐tetrahydro‐1H‐chromeno[2,3‐d]pyrimidin‐5‐yl)pyrimidione derivatives have been synthesized from substituted salicylaldehydes and barbituric acid or 2‐thiobarbituric acid in water catalyzed by phase transfer catalysis of triethylbenzyl ammonium chloride (TEBA). Elemental analysis, IR, ¹H NMR, and ¹³C NMR elucidated the structures of all the newly synthesized compounds. In vitro antimicrobial activities of synthesized compounds have been investigated against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa. These newly synthesized derivatives exhibited significant in vitro antibacterial activity.     

Synthesis,Docking, ADME‐Tox Study of 2‐(2‐(2‐Chlorophenyl)quinoline‐4‐carbonyl)‐N‐substituted hydrazinecarbothioamide Derivatives and Their Biological Evaluation

A series of 2‐(2‐(2‐chlorophenyl)quinoline‐4‐carbonyl)‐N‐substituted hydrazinecarbothioamide derivatives were synthesized by facile and efficient conventional method. The structures of the compounds were elucidated with the aid of an elemental analysis, IR, ESI‐MS, ¹H‐NMR, and ¹³C‐NMR spectral data. The synthesized compounds were evaluated for their in vitro antibacterial, antifungal, antimalarial, and antituberculosis activity against standard drugs. The bacterial studies were determined against gram‐positive and negative bacteria. These compounds were found to a broad spectrum of activity against the screened bacteria, but poor activity was observed against Pseudomonas aeruginosa and Escherichia coli. Compounds 8d , 8f , 8i , 8l , and 8n showed the potent activity against Staphylococcus aureus. Compounds 8d , 8g , 8k , 8l , and 8q show the potent activity against antimalarial as compared with the standard drugs Chloroquine, Quinine and compounds 8h , 8n , and 8o shows mild activity against H37Rv strain. Molecular docking revealed that synthesized derivatives and target proteins were actively involved in a binding pattern and had a significant corelation with biological activity. We have also performed a molecular dynamics and ADME‐Tox parameters for the synthesized compounds.     

Synthesis of Novel 3‐Acetyl‐2‐Aryl‐5‐(3‐Aryl‐1‐Phenyl‐Pyrazol‐4‐yl)‐2,3‐Dihydro‐1,3,4‐Oxadiazoles

A series of novel pyrazolyl‐substituted 1,3,4‐oxadiazole derivatives ( 4a‐4o ) were prepared by cyclization of the intermediate N′‐((3‐aryl‐l‐phenyl‐pyrazol‐4‐yl)methylene)arylhydrazide with acetic anhydride. The structures of the new compounds were confirmed by IR, ¹H NMR, MS and elemental analysis. Furthermore, preliminary bioassay of some of the title compounds indicated that they exhibited moderate inhibition against HIV‐1 PR.     

Synthesis,Characterization, and DGAT1 Inhibition of New 5‐Piperazinethiazole and 5‐Piperidinethiazole Analogs

In this study, a novel series of 5‐piperazinethiazole 2,2‐dimethylbutanoic acid and 5‐piperidinethiazole 2,2‐dimethylbutanoic acid derivatives have been synthesized. Structures of the newly synthesized compounds have been elucidated using ¹H‐NMR, ¹³C‐NMR, high‐resolution mass spectroscopy, and high‐performance liquid chromatographic analysis. The synthesized derivatives have been evaluated in vitro for their ability to inhibit the enzyme diacylglycerol acyltransferase 1 responsible for triglyceride biosynthesis.     

Synthesis of Polysubstituted‐1,2,4‐Triazoles

A new series of substituted 1,2,4‐triazole derivatives have been synthesized using substituted imido derivatives and isonicotinyl hydrazine (or 4‐nitrobenzoylhydrazine) as the key intermediates. These compounds include different donor or acceptor substituents on the 1,2,4‐triazole derivatives. The structures of these compounds were confirmed by FTIR, ¹H‐NMR, ¹³C‐NMR, and elemental analysis.     

由邻苯二胺合成苯并咪唑、喹喔啉以及1-H-2,3－二氢1,5-苯并氮杂卓

A series of benzo-fused heteroaromatic compounds with 5-, 6- and 7-membered tings, such as benzimidazole,quinoxaline and 1H-1,5-benzodiazepine derivatives, were synthesized through condensation reaction of o-pheny1-enediamine with ary1 aldehydes or ketones. The experimental conditions were carefully examined, and the products were characterized by ^1H NMR, ^13C NMR, MS, IR and elemental analyses. In addition, the structure of a benzodiazaepine derivative with 7-membered ring was confirmed by single crystal X-ray diffraction analysis.     

Synthesis and Pharmacological Evaluation of a Novel Series of 2‐((2‐Aryl thiazol‐4‐yl)methyl)‐5‐(alkyl/alkylnitrile thio)‐1,3,4‐oxadiazole Derivatives as Possible Antifungal Agents

In the present investigation, a novel series of 2‐[(2‐arylthiazol‐4‐yl)methyl]‐5‐(alkyl/alkylnitrile thio)‐1,3,4‐oxadiazole derivatives were synthesized by cyclo‐condensation of 2‐(2‐substituted thiazol‐4‐yl)aceto hydrazide with carbon disulfide followed by S‐alkylation with alkyl halide in dry acetone. All the newly synthesized compounds were characterized by spectral (IR, ¹H NMR, ¹³C NMR, mass, and elemental analysis) methods. The title compounds were screened for in vitro antifungal activity and most of the synthesized compounds show moderate to good antifungal activity.     

Efficient and Facile Catalyst‐free One‐Pot Synthesis and Characterization of Some Novel Bis(2‐benzothiazole) Derivatives

A general method for preparation of benzothiazole derivatives including oxidative cyclization of the corresponding Schiff bases was reported. Herein, we have been synthesized a series of new acyclic‐substituted bis(2‐arylbenzothiazoles). Synthesis of analogs substituted in the benzothiazole ring was achieved via the direct condensation reaction of o‐aminothiophenol with some of dialdehyde compounds under catalyst free in high yields. The structure of these products has been fully characterized by physical and spectroscopic data such as IR, ¹H‐NMR, ¹³C‐NMR, UV‐Vis, MS, and CHN analysis.     

Synthesis and pharmacological properties of N‐substituted‐N′‐(4,6‐dimethylpyrimidin‐2‐yl)‐thiourea derivatives and related fused heterocyclic compounds

A series of new N‐Substituted‐N′‐(4,6‐dimethylpyrimidin‐2‐yl)‐thiourea derivatives ( 3a , 3b , 3c , 3d ) and related fused heterocyclic compounds ( 4a , 4b , 4c , 4d ) were synthesized using tetrabutylammonium bromide as phase transfer catalyst (PTC). N‐[(2E)‐5,7‐dimethyl‐2H‐[1,2,4] thiadiazolo [2,3‐a] pyrimidin‐2‐ylidene] derivatives ( 4a , 4b , 4c , 4d ) were prepared by oxidative cyclization of 3a , 3b , 3c , 3d . The structures of these novel compounds were characterized by IR, ¹H NMR, ¹³C NMR, mass spectrometry, and the elemental analysis. The crystal structures were determined from single crystal X‐ray diffraction data. The results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms and showed higher activity against fungi than bacteria. Compounds 3d and 3a exhibited the greatest antimicrobial activity. J. Heterocyclic Chem., 2011.     

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 and Characterization of New Thebaine Derivatives as Potential Opioid Agonists and Antagonists: 2‐[N‐(1H‐Tetrazol‐5‐yl)‐6,14‐endo‐etheno‐6,7,8,14‐tetrahydrothebaine‐7α‐yl]‐5‐phenyl‐1,3,4‐oxadiazoles

In this study, we report the synthesis a series of novel 2‐[N‐(1H‐tetrazol‐5‐yl)‐6,14‐endo‐etheno‐6,7,8,14‐tetrahydrothebaine‐7α‐yl]‐5‐phenyl‐1,3,4‐oxadiazole derivatives ( 7a – e ) which have potential opioid antagonist and agonist. The substitution reaction of 6,14‐endo‐ethenotetrahydrothebaine‐7α‐carbohydrazide with corresponding benzoyl chlorides gave diacylhydrazine compounds 4a – e in good yields. The treatment of compounds 4a – e with POCl₃ caused the conversion of side‐chain of compounds 5a – e into 1,3,4‐oxadiazole ring at C(7) position; thus, compounds 5a – e were obtained. Subsequently, cyanamides ( 6a – e ) were prepared from compounds 5a – e and then compounds 7a – e were synthesized by the azidation of 6a – e with NaN₃. The structures of the compounds were established on the basis of their IR, ¹H NMR, ¹³C APT, 2D‐NMR (COSY, NOESY, HMQC, HMBC) and high‐resolution mass spectral data.     

Synthesis of New Triazole and Oxadiazole Derivatives of Quinazolin‐4(3H)‐one and Their Antimicrobial Activity

A series of new triazole derivatives of quinazolin‐4(3H)‐one and new oxadiazole derivatives of quinazolin‐4(3H)‐one were synthesized. The newly synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR and mass spectral data. All the newly synthesized compounds were screened for antibacterial activity against Staphylococcus aureus, Bacillus subtilis (gram‐positive bacteria), Escherichia coli, Pseudomonas aeruginosa (gram‐negative bacteria), and antifungal activity was carried out against Candida albicans and Aspergillus niger.     

Synthesis of New 1,2,3‐Triazole Derivatives Possessing 4H‐Pyran‐4‐one Moiety by 1,3‐Dipolar Cycloaddition Reaction of Azidomethyl Phenylpyrone with Various Alkynes

A series of new 1,2,3‐triazole derivatives were synthesized by 1,3‐dipolar cycloaddition reaction of 2‐(4‐azidomethylphenyl)‐6‐phenyl‐4H‐pyran‐4‐one with different alkynes in 40–71% yields. In the case of terminal alkynes, the reaction was proceeded in the presence of Cu(I) catalyst. The structure of the synthesized compounds were confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy and elemental analysis.     

Synthesis and Biological Activities of Novel 6‐Alkylamino‐11,12‐dihydro‐11‐arylbenzo[c]phenanthridine Derivatives

A series of novel benzo[c]phenanthridine derivatives 2a , 2b , 2c , 2d , 2e , 2f , 2g , 2h , 2i , 2j , 2k , 2l , 2m and 3a , 3b , 3c , 3d , 3e , 3f bearing an alkylamino side chain at their 6‐position were synthesized. All of the target compounds were confirmed by ¹H NMR, ¹³C NMR, and HRMS, and some of them were also characterized by IR and ¹⁹F NMR. The preliminary bioassays showed that the target compounds displayed fungicidal activities; for example, compound 2l showed 60.0% and 70.0% inhibitive activity against Alternaria solani and Cercospora arachidicola at 50 mg/L, respectively, and some compounds also displayed plant growth‐regulating activities.     

Studies with 2‐(acetonylthio)benzothiazole: Novel synthesis of pyridazin‐6(1H)‐one,pyridazin‐6(1H)‐imine,and phthalazine derivatives of antimicrobial and antifungal activities

A novel series of (Z)‐1‐(arylhydrazono)‐1‐(benzothiazol‐2′‐ylthio)propan‐2‐ones have been prepared and their utility as building blocks in the synthesis of novel derivatives of Pyridazin‐6(1H)‐ones, pyridazin‐6(1H)‐imines, and phthalazine incorporating a benzothiazole residue are investigated. All of the title compounds were confirmed by elemental analysis, IR, ¹H NMR, ¹³C NMR, NOE, and mass spectrometry. The synthesized compounds are screened for their antibacterial as well as antifungal activity. All the tested compounds showed high to moderate activity against the selected microorganisms. J. Heterocyclic Chem., (2011).     

Synthesis,Structure, and Biological Activities of 10‐Substituted 3,3,6,6‐Tetramethyl‐9‐Aryl‐3,4, 6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione Derivatives

A series of 10‐substituted‐3,3,6,6‐tetramethyl‐9‐aryl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H ,5 H )‐dione derivatives 2 were synthesized by reaction of compounds 1 with amines. The compounds 1 were effectively prepared by 5,5‐dimethylcyclohexane‐1,3‐dione and aldehydes in the presence of a little amount of L‐proline as catalyst at room temperature. All the compounds were characterized by IR, MS, and ¹H NMR. The crystal data of 1b and 2d were collected by X‐ray single‐crystal diffraction, and compounds 2b and 2d exhibited better inhibitory activity against HepG2 cells.     

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.