Studies on Antimicrobial Evaluation of Some 1-((1-(1H-Benzo[d]imidazol-2-yl)ethylidene)amino)-6-((arylidene)amino)-2-oxo-4-phenyl-1, 2-dihydropyridine-3,5-dicarbonitriles

A new series of 1-((1-(1H-benzo[d]imidazol-2-yl)ethylidene)amino)-6-((arylidene)amino)-2-oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitriles (4a–o) have been synthesized for the development of antimicrobial agents. Newly synthesized compounds were evaluated for their in vitro antibacterial activity against Gram-positive bacteria (Pseudomonas aeruginosa, Streptococcus pyogenes), Gram-negative bacteria (Escherichia coli, Staphylococcus aureus), and antifungal activity (Candida albicans, Aspergillus niger, Aspergillus clavatus). These compounds were characterized by infrared, ¹H NMR, ¹³C NMR, and mass spectra. The synthesized compounds 4b, 4e, 4 h, and 4k showed potent antimicrobial activity against tested microorganisms.     

Synthesis and microbial screening of 8-(benzyloxy)-5-(2-[1,3-diphenyl-1H-pyrazol-4-yl]thiazol-4-yl)quinolin-2(1H)-one derivatives

The present investigation describe the synthesis of 8-(benzyloxy)-5-(2-[1,3-diphenyl-1H-pyrazol-4-yl]thiazol-4-yl)quinolin-2(1H)-one derivatives. Quinolin-8-ol was transformed by five step synthetic procedures into 8-Benzyloxy-5-(2-bromo-acetyl)-1H-quinolin-2-one. Subsequently, 8-Benzyloxy-5-(2-bromo-acetyl)-1H-quinolin-2-one condensed with 1,3-Diphenyl-1H-pyrazole-4-carbothioic acid amide in the presence of acetonitrile to afford 8-(benzyloxy)-5-(2-[1,3-diphenyl-1H-pyrazol-4-yl]thiazol-4-yl)quinolin-2(1H)-one derivatives. Synthesized compounds were screened for their antimicrobial activity against gram-positive and gram-negative bacteria. Most of the synthesized compounds are found to be active against tested bacterial strains and fungal strain.     

Synthesis of (-)-(S)-3-sec-butyl- and (+)-(S)-5-sec-butyl-2(1H)-pyridinone

Optically active (+)-(S)-5-sec-butyl- and (-)-(S)-3-sec-butyl-2(1H)-pyridinone are synthesized and the relationship between optical activity and minimum optical purity of the latter is determined.     

Design,synthesis and antibacterial activity evaluation of novel 2-(4-((1-aryl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)2-(2-oxoazetidin-1-yl)acetamide derivatives

In this paper, a novel series of 2-(4-((1-aryl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)2-(2-oxoazetidin-1-yl)acetamide derivatives are synthesized in two steps. The first step involved Ugi multicomponent reaction of β-alanine, o-(propargyl)benzaldehyde and isocyanide derivatives. The product of this step, underwent a click 1,3-dipolar cycloaddition reaction with benzyl azide derivatives. The 2-(4-((1-aryl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)2-(2-oxoazetidin-1-yl)acetamide product was characterized and their antibacterial activities were evaluated against various G-positive (Staphylococcus aureus and Bacillus subtilis) and G-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria, using minimal inhibition concentration. The compounds showed very good antimicrobial activity and a number of products have been more active than ciprofloxacin.     

Synthesis and antimycobacterial screening of new 4-(4-(1-benzyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-3-yl)quinoline derivatives

A new series of 4-(4-(1-benzyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-3-yl)quinoline ( 6a-t ) have been synthesized by a click reaction of 4-(4-ethynyl-1-phenyl-1H-pyrazol-3-yl)quinoline ( 4a-d ) with a substituted benzyl azide ( 5a-e ). The starting alkyne derivatives 4a-d are obtained from Bestmann-Ohira reaction of 1-phenyl-3-(quinolin-4-yl)-1H-pyrazole-4-carbaldehyde and dimethyl(1-diazo-2-oxopropyl)phosphonate. The newly synthesized compounds are screened against M. tuberculosis H37Ra dormant and active, Escherichia coli, Pseudomonas fluorescence, Staphylococcus aureus and Bacillus subtilis strains at 30 μg/mL concentration. Most of the screened compounds showed good to moderate antibacterial activity against S. aureus, B. subtilis, and Mycobacterium tuberculosis H37Ra strains. The synthesized derivatives of quinolinyl-pyrazole-4-carbaldehyde and quinolinyl-pyrazole-4-ethyne reportd good to moderate activity against both strains of M. tuberculosis H37Ra. Ten derivatives of quinolinyl-pyrazole presented good activity against B. subtilis. These results suggested that further optimization and development of quinolinyl-pyrazolyl-1,2,3-triazole moeity could serve as lead compounds for antimycobacterial activity.     

Green synthesis of 1,3,4-oxadiazole derivatives based on N-arylidene-2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide as potential antitumor agents

Design of a new series of 1,3,4-oxadiazole derivatives was achieved in good yield via treatment of N-arylidene-2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide with cerium (IV) ammonium nitrate as a catalyst. They can be formulated also using one-pot reaction of 2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide, aromatic aldehyde and cerium (IV) ammonium nitrate in dichloromethane. The structural formulas of all synthesized products were elucidated based on their elemental and spectral analyses. In addition, MTT assay was used to evaluate antitumor activity of the synthesized molecules and some of them showed potent activity in comparison with Doxorubicin as a standard drug.     

Synthesis of novel 6-(substituted amino)-4-(4-ethoxyphenyl)-1-phenyl-2(1H)-pyridinones via azo coupling

Abstract  

6-(Substituted amino)-4-(4-ethoxyphenyl)-1-phenyl-2(1H)-pyridinones were prepared from β-aryl glutaconic acid, which, on fusion with aniline, results in 4-(4-ethoxyphenyl)-1-phenylpyridine-2,6(1H,5H)-dione. This, on further treatment with phosphorus oxychloride gave 6-chloro-4-(4-ethoxyphenyl)-1-phenyl-2(1H)-pyridinone, and further treatment with secondary amines yielded 6-(substituted amino)-4-(4-ethoxyphenyl)-1-phenyl-2(1H)-pyridinones. These were subjected to azo coupling with different aryldiazonium chlorides furnishing two isomers, which were separated by column chromatography. All compounds were characterized by elemental analysis, and use of IR and NMR spectral data, and were evaluated for antimicrobial activity.     

Synthesis and optical behaviors of 2-(9-phenanthrenyl)-, 2-(9-anthryl)-, and 2-(1-pyrenyl)-1-alkylimidazole homologues

Eight 2-(9-phenanthrenyl)-, 2-(9-anthryl)- and 2-(1-pyrenyl)-1-alkyl-benzimidazole compounds, three 2-(9-anthryl)-1-alkylphenanthroimidazole compounds and five 4,5-diphenyl-1-alkyl-2-(9-anthryl)imidazole compounds were synthesized by alkylation reactions of the corresponding benzimidazole, phenanthroimidazole or imidazole compounds. 2-(10-Bromo-9-anthryl)-1-alkyl-benzimidazole compounds were prepared by bromination reaction of 2-(9-anthryl)-1-alkylbenzimidazole compounds. All the synthesized compounds were characterized by elemental analysis, ¹H NMR, ¹³C NMR, MS or HRMS; their absorption coefficients (), maximum absorption λ_amax, fluorescence emission maximum λ_em, Stokes shifts and fluorescence quantum yields (Φ_F) in ethyl acetate were determined; their fluorescent lifetimes (T₁ and T₂) were measured in ethyl acetate and in solid state, respectively. The crystal structure of 2-(9-anthryl)-1-n-butyl-4,5-diphenylimidazole (12a) was determined to be triclinic, space group P-1 types, using single crystal X-ray crystallography technique. The results showed that these compounds exhibited moderate fluorescence-emission abilities and higher solubility in most organic solvents than their corresponding starting materials. The relationships between the optical behaviors and structures for these compounds were discussed.     

Synthesis of 1-(N-piperidinoacetyl)-4-arylthiosemicarbazides as possible anticonvulsants

Several 1-(N-piperidinoacetyl)-4-arylthiosemicarbazides were synthesized from N-piperidinoacetyl hydrazide, which was obtained by the reaction of hydrazine hydrate with ethyl N-piperidinoacetate. The anticonvulsant activity of these substituted thiosemicarbazides was reflected by their ability to provide 10–50% protection against pentylenetetrazol-induced convulsions in mice. All substituted thiosemicarbazides (0.3 mM) inhibited in vitro monoamine oxidase activity of rat brain homogenates and provided 21–86% protection against hypoosmotic hemolysis at a final concentration of 0.1 mM.     

Crystallographic characterization of three cathinone hydrochlorides new on the NPS market: 1-(4-methylphenyl)-2-(pyrrolidin-1-yl)hexan-1-one (4-MPHP), 4-methyl-1-phenyl-2-(pyrrolidin-1-yl)pentan-1-one (α-PiHP) and 2-(methylamino)-1-(4-methylphenyl)pentan-1-one (4-MPD)

Cathinones belong to a group of compounds of great interest in the new psychoactive substances (NPS) market. Constant changes to the chemical structure made by the producers of these compounds require a quick reaction from analytical laboratories in ascertaining their characteristics. In this article, three cathinone derivatives were characterized by X-ray crystallography. The investigated compounds were confirmed as: 1-[1-(4-methylphenyl)-1-oxohexan-2-yl]pyrrolidin-1-ium chloride ( 1 , C₁₇H₂₆NO⁺·Cl^?, the hydrochloride of 4-MPHP), 1-(4-methyl-1-oxo-1-phenylpentan-2-yl)pyrrolidin-1-ium chloride ( 2 ; C₁₆H₂₄NO⁺·Cl^?, the hydrochloride of α-PiHP) and methyl[1-(4-methylphenyl)-1-oxopentan-2-yl]azanium chloride ( 3 ; C₁₃H₂₀NO⁺·Cl^?, the hydrochloride of 4-MPD). All the salts crystallize in a monoclinic space group: 1 and 2 in P2₁/c, and 3 in P2₁/n. To the best of our knowledge, this study provides the first detailed and comprehensive crystallographic data on salts 1 – 3 .     

Synthesis of (s)-1-{3-[4-(4-benzo[d]isothiazol-3-yl-piperazin-1-yl)-3-fluoro-phenyl]-2-oxo-oxazolidin-5-ylmetyl}-3-substituted-urea derivatives as antibacterial agents

A new series of (s)-1-{3-[4-(4-benzo[d]isothiazol-3-yl-piperazin-1-yl)-3-fluoro-phenyl]-2-oxo-oxazolidin-5-ylmetyl}-3-substituted-urea derivatives have been synthesized and characterized with spectral data, such as IR, NMR and Mass spectroscopies. All compounds are in vitro evaluated for their efficacy as antimicrobial agent against the gram-positive pathogenic strains such as Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228 and Streptococcus pyogens ATCC 8668. Five compounds ( 19k , 19l , 19m , 19n and 19o ) out of 15 compounds showed moderate activity.     

(+)-(5R,6S)-2-(1′-Aminoalkyl)-6-(hydroxyalkyl)penem-3-carboxylic Acids

In continuation of our work on penem antibiotics, novel chiral (5R,6S)-2-(1′-aminoalkyl)-6-(hydroxyalkyl)-derivatives 1 have been synthesized by two essentially different strategies. Whereas the starting materials for 1a - f , azetidinones 2 and 5 , were obtained from chiral building blocks (6-aminopenicillanic acid and L-threonine, resp.), the one for 1g , azetidinone 9 , was derived from racemic 4-acetoxyazetidinone and, as chiral auxiliary, (2R)-2-mercaptopropan-1-ol. The 2-aminomethyl derivatives 1a (CGP 30 779) and 1f (CGP 31 608) proved the most potent compounds in the antibacterial tests in vitro and showed a well-balanced spectrum of activity by comparison with that of established β-lactams.     

Synthesis, characterization, and biological activities of some transition metal(II) complexes with the thiosemicarbazone derived from 4-[1-(4-methylphenylsulfonyl)-1H-indol-3-yl]but-3-en-2-one

A new 4-[1-(4-methylphenylsulfonyl)-1H-indol-3-yl]but-3-en-2-one thiosemicarbazone (HL) was synthesized derived from 4-[1-(4-methylphenylsulfonyl)-1H-indol-3-yl]but-3-en-2-one. Four transition metal(II) complexes of HL have been prepared. Elemental analysis, molar conductivity, IR, UV, ¹H NMR spectra, and TG-DTA have been used to characterize these complexes. The complexes have the general formula ML₂, where M = Zn, Cu, Co, and Ni. The ligand and its complexes have been studied for their possible biological activity including anti-inflammatory, antibacterial, and antitumour activity in vitro.     

1-(嘧啶基-4)-3-(2,6-二氟苯甲酰基)脲衍生物的合成与生物活性

为了寻找高效、低毒、低残留的环境友好杀虫剂, 设计并合成了12个新的1-(嘧啶基-4)-3-(2,6-二氟苯甲酰基)脲衍生物6a～6l, 其结构经IR, ¹H NMR, LC/MS和元素分析确证. 初步生物活性测试结果表明, 部分化合物具有明显的杀虫活性, 如6g在100 mg/L浓度下, 对粘虫(Mythimna sepatara)具有100%的杀虫活性.     

A Simple Route to New N(3)-Substituted 5-Aryl-2-(dialkylamino)-1,3-oxazolium Salts and N(1)-Substituted 4-Aryl-2-(dialkylamino)-1H-imidazoles

In the reaction of N,N-dialkyl-dichloromethaniminium chlorides 11 with 2-aminoacetophenones 12 , a general and simple route to heretofore unknown 5-aryl-substituted 2-(dialkylamino)-1,3-oxazolium salts 13 and 5-aryl-substituted 2-(dialkylamino)oxazoles 14 was found. From the 2-(dialkylamino)-1,3-oxazoles 14 , the corresponding oxazolium salts 13 were obtained after alkylation with (MeO)₂SO₂. The new oxazolium salts 13 were converted to 1-substituted 4-aryl-2-(dialkylamino)-1H-imidazoles 9 by treatment with NH₄OAc. The possible use of these 1H-imidazoles as dye educts was explored. Analytical data, as well as AM1 calculations, reveal some remarkable differences between the structures of the neutral imidazoles 9 and their positively charged oxazolium precursors 13 .     

Synthesis of diverse (E)-2-((1H-imidazol-1-yl)methyl)-2-((benzyloxy)methyl)-2,3-dihydro-1H-inden-1-one O-benzyl oxime derivatives as potent antileishmanial agents

A series of (E)-2-((1H-imidazol-1-yl)methyl)-2-((benzyloxy)methyl)-2,3-dihydro-1H-inden-1-one O-benzyl oximes ( 6a-j ) were prepared and evaluated for their in vitro antileishmanial potency against Leishmania donovani (in promastigote and amastigote models). At a concentration of 05-μg/mL, compounds 3a-d , 4a-d , 5a , 5b , 6a-d, and 7a-d exhibited 97% to 100% and 87% to 100% inhibition against promastigotes and amastigotes, respectively. Compounds 6a , 6d-6j and 6a , 6i , 6j exhibited equal antileishmanial potency to that of SSG and Pentamidin at lower values of IC₅₀.     

Effective pH sensors based on 1-(anthracen-9-ylmethyl)-1H-benzimidazol-2-amine

1-(Anthracen-9-ylmethyl)-1H-benzimidazol-2-amine was synthesized by alkylation of benzimidazol-2-amine with 9-chloromethylanthracene, and a series of azomethines based on it was obtained. Spectral investigations of the 9-anthrylmethylbenzimidazole derivatives revealed their high chemosensor activity with respect to hydrogen cations. Quantum-chemical investigation of the structures obtained showed that they possess high proton affinity and can be regarded as analogs of “proton sponges”.     

Synthesis,antioxidant, and antimicrobial activity of 3-(1H-indole-3-carbonyl)-2H-chromen-2-ones

A simple and convenient method for the one-pot synthesis of 3-(1H-indole-3-carbonyl)-2H-chromen-2-one derivatives from the reaction of 3-cyanoacetyl indole and salicylaldehyde in the presence of Na₂CO₃ in water: methanol (1:1) is described. Wider substrate scope, high yields, operational simplicity, and simple purification process make the protocol highly applicable in the synthesis of 3-(1H-indole-3-carbonyl)-2H-chromen-2-ones. For the first time, in vitro antioxidant and antimicrobial activity was studied. Compounds 5e , 7a , and 7b exhibits good radical scavenging ability against DPPH free radical. Compounds 7b , 5f , and 5g possess lower EC₅₀ values than the Standards AA and BHA and thus proving their high reducing power. Compounds 5d and 5f show good antibacterial activity against gram-positive bacteria (MRSA) while compounds 5c , 7a , and 7b exhibits good antibacterial activity against Bacillus sp. Compounds 5b and 5e show good antibacterial activity against gram negative bacterial strains (Escherichia coli, Klebsiella pneumoniae) and compounds 5g and 5h exhibits good antifungal activity against Candida albicans.     

Synthesis and determination of maximum rotatory power of (+)-(S)-5-s-butyl-2(1H)-pyridinone

Optically active (S)-5-s-butyl-2(1H)-pyridinone ( 6 ) is obtained by reaction of 2-s-butylacrolein ( 1 ) and N-(carbamylmethyl)pyridinium chloride. The relationship between optical activity and minimum optical purity is determined.     

Synthesis,characterization, antifungal and antibacterial activities evaluation of copper (II), zinc (II) and cadmium (II) chloride and bromide complexes with new (E)-1-(3,4-dimethoxybenzylidene)-4-methylthiosemicarbazone ligand

The reactions of Cu (II), Zn (II) and Cd (II) chloride or bromide with (E)-1-(3,4-dimethoxybenzylidene)-4-methylthiosemicarbazone (MTSVT) lead to the formation of new complexes. They were characterized by spectroscopic studies: IR, ¹H and ¹³C NMR. The crystal structures of the compounds [MTSVT] ( L ), [ZnBr₂(MTSVT)₂] ( 2 ), [CdCl₂(MTSVT)₂] ( 3 ) and [CdBr₂(MTSVT)₂^.H₂O] ( 4 ) were determined by X-ray diffraction. For complexes 2 – 4 , the ion is coordinated through the sulfur atom. All compounds were tested for their antifungal activity against human pathogenic fungi Candida albicans and Aspergillus fumigatus, and for their antibacterial activity against Gram (+) Bacillus subtilis and Enterococcus faecalis as well as against Gram (−) bacteria such as Paracoccus yeei and Acinetobacter baumanii. The results indicated that the metal complexes exhibited a marked enhancement in antibacterial activity compared with the parent Schiff base.