Synthesis and antimicrobial evaluation of some heterocyclic chalcone derivatives

Some new heterocyclic compounds containing isoxazole, pyrazole and oxadiazole ring systems were prepared from various chalcones. The synthesized compounds have been characterized by elemental analysis and spectral methods. These compounds were screened for their antimicrobial activities.     

Synthesis of D-Ala--D-Ala analogues with postulated antibacterial activity

The syntheses of the L,L- and D,D-stereoisomers of N-phenoxyacetyl-X-alanine in which X=His, Tyr, or Lys, are described. The antibacterial activity of some of the peptide derivatives and their synthetic intermediates have been examined. Some of the intermediates exhibited moderate activity against viridans streptococci, enterococci and Streptococcus agalactiae. None of the compounds were active against beta-lactamase producing bacteria or served as beta-lactamase inhibitors.     

Synthesis and antibacterial activity of chalcone derivatives containing thioether triazole

The infection of Xanthomonas oryzae pv. Oryzae (Xoo), Ralstonia solanacearum (Rs), and Xanthomonas axonopodis pv. Citri (Xac) has become a major problem in agricultural production. In this study, a series of novel chalcone derivatives containing thioether triazoles were designed and synthesized. The structures of the novel compounds were systematically characterized via ¹H-NMR, ¹³C-NMR, and HRMS. Moreover, the antibacterial activity results showed that E₁₀, E₁₁, E₁₅, and E₁₆ have adequate antibacterial activities against Xoo, Rs, and Xac. Among the different compounds, E₁₅ exhibited remarkable inhibitory effect against Xac with an EC₅₀ of 9.1 μg.mL^-1, which was better than that of commercial agent bismerthiazol (54.9 μg.mL^-1). In addition, the possible antibacterial mechanism of the target compound E₁₅ against Xac was studied via scanning electron microscopy (SEM).     

Synthesis of some sulfonamide derivatives with potential antibacterial activity

Some new quinoxaline-6-sulfonamide and phthalazine-6-sulfonamide derivatives were synthesized. The majority of the prepared compounds showed antibacterial activity.Faculty of Pharmacy, University of Tanta, Egypt. Fax: 002 040 335466Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 523–528, April, 2000.     

Synthesis and antibacterial activity of some novel triazolothienopyrimidines

A novel series of some novel 5-substituted-1,2,4-triazolo[4,3-c]8,9,10-trihydrocyclopenta/8,9,10,11,12-pentahydrocyclohepta[b]thieno[3,2-e]pyrimidin-3-thiones has been synthesized. The intermediates 4-chloro-2-substituted-5,6,7-trihydrocyclopenta/5,6,7,8,9-pentahydrocyclohepta[b]thieno[2,3-d]pyrimidines were prepared by warming 2-substituted-5,6,7-trihydrocyclopenta/5,6,7,8,9-pentahydrocyclohepta[b]thieno[2,3-d]pyrimidin-4[3H]-ones with oxalyl chloride. Thieno[2,3-d]pyrimidin-4[3H]-ones were prepared by a novel, microwave assisted, solvent free, synthetic route under basic conditions hitherto unreported in the literature from ortho amino ester of thiophene. The chloro derivatives, without further purification, were hydrazinated to yield 2-substituted-4-hydrazino-5,6,7-trihydrocyclopenta/5,6,7,8,9-pentahydrocyclohepta[b]thieno[2,3-d]pyrimidines. These compounds were cyclized with carbon disulphide to give the title compounds in quantitative yields. The final compounds were screened for antibacterial activity by Kirby Bauer's method using ampicillin as the standard against various gram positive and gram negative bacteria. All the compounds showed antibacterial activity comparable with the standard.     

Synthesis and antimicrobial activity of some netropsin analogues

Nine novel lexitropsins were synthesized by linking two netropsin-like moieties through three different dicarboxylic acids; 9,10-dihydro-2,7-phenanthrenedicarboxylic acid; [(3-[[(carboxymethyl)amino]carbonyl]benzoyl)amino]acetic acid and indole-2,5-dicarboxylic acid. The netropsin residues were modified by the use of N-isopentylpyrrole, 5-methylthiophene or 5-isopropylthiazole heterocyclic building blocks in place of the usual N-methylpyrrole. The compounds were tested against five gram-positive bacteria: Staphylococcus aureus, Streptomyces faecalis, methicillin resistant Staphylococcus aureus, Enterobacter cloacae, Mycobacterium fortuitum, three gram-negative bacteria: Klebsiella aerogenes, Proteus vulgaris, Escherichia coli and three fungi: Aspergillus niger, Candida albicans and Aspergillus nidulans. Some of the compounds showed significant inhibitory effects on the growth of the microorganisms.     

Synthesis and antibacterial activity of some novel pyrazolopyridine derivatives

Eight pyrazolo[3,4-b]pyridine derivatives have been synthesized by Friedl?nder condensation of 5-aminopyrazole-4-carbaldehyde with active methylene compounds in basic medium. These compounds have been screened for their antibacterial activity against two Gram-negative and two Gram-positive bacterium. Pyrazolopyridines having the carboxamide group at the 5-position showed moderate to good activity against P. aeruginosa, E. coli, S. pneumoniae, and B. cereus.     

Synthesis of caprazamycin analogues and their structure--activity relationship for antibacterial activity

Synthesis of palmitoyl caprazol 7, which possesses a simple fatty acyl side chain at the 3' '-position of the diazepanone moiety, was carried out and their antibacterial activity was evaluated. The key elements of our approach include the improved synthesis of the key 5'-beta-O-aminoribosyl-glycyluridine derivative, installation of the palmitoyl side chain to the cyclization precursor, and the construction of the diazepanone by an intramolecular reductive amination. The second generation synthesis of (+)-caprazol was also established. Palmitoyl caprazol 7 exhibited antibacterial activity against Mycobacterium smegmatis ATCC607 (MIC = 6.25 microg/mL) with potency similar to that of the caprazamycins (CPZs). Palmitoyl caprazol 7 and N6'-desmethyl palmitoyl caprazol 28 also exhibited antibacterial activity against drug-resistant bacteria including methyciline-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) strains (MIC = 3.13-12.5 microg/mL).     

Synthesis of heterocyclic analogs of chalcone containing the selenophene ring

Crotonaldehyde-type condensation using alkaline or acid catalyst is used to synthesize 14 chalcone analogs containing in addition to the selenophene ring, a number of other heterocyclic groups. A Michael adduct is shown to be formed by reaction of 2-acetylselenophene with 2-pyridine aldehyde.     

Synthesis of some heterocyclic spirocompounds

1,3-Dipolar cycloaddition reactions of methylenepyrrolidinones with nitrilimines or nitrones resulted in regio and stereoselective formation of respective spiropyrazolines or spiroisovazolidines.Department of Organic Chemistry, Slovak Technical University, Radlinského 9, 81237 Bratislava, Slovak Republic. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1353–1355, October, 1995. Original article submitted August 24, 1995.     

Synthesis,characterization, POM analysis and antifungal activity of novel heterocyclic chalcone derivatives containing acylated pyrazole

Research on Chemical Intermediates - A series of heterocyclic chalcone derivatives (4a–h) were synthesized and characterized by IR, 1H and 13C NMR as well as MS. All the synthesized compounds...     

Synthesis and antifungal activity of chalcone derivatives

In the present study, using chalcone as a lead compound, a series of its derivatives (compounds 1–30) were designed and synthesised. Their activity of anti-pathogenic fungi of plants has been evaluated. It is found that these compounds have good antifungal activity against Sclerotinia sclerotiorum, Helminthosprium maydis, Botrytis cinerea, Rhizoctonia solani and Gibberella zeae. Among them, the inhibition of growth for compound 30 against S. sclerotiorum showed 89.9%, with the median effective concentrations (EC₅₀) of 15.4 μg mL^? 1. The inhibition of growth for compounds 28, 29 and 30 at a concentration of 100 μg mL^? 1 against H. maydis is 90.3%, 90.7% and 91.1%, with EC₅₀ of 15.1, 18.3 and 18.1μg mL^? 1, respectively.     

Synthesis, characterization, and antioxidant activity of some ebselen analogues

Simple synthetic routes for several analogues of the anti-inflammatory organoselenium drug, ebselen, are described. The compounds are characterized by (1)H, (13)C, and (77)Se NMR spectroscopy and mass spectral techniques and, in some cases, by single-crystal X-ray diffraction studies. The glutathione peroxidase (GPx)-like antioxidant activity has been studied by using H(2)O(2), tBuOOH, and Cum-OOH as substrates, and thiophenol (PhSH, 4-Me-C(6)H(4)SH) and glutathione (GSH) as cosubstrates. Density functional theory (DFT) calculations have been performed on these systems to understand the effects of various substituents on the (77)Se NMR chemical shifts; these results have been compared with the experimental data. The experimental and theoretical results suggest that the presence of a phenyl substituent on the nitrogen atom is important for the antioxidant activity of ebselen. While ebselen and its analogues are poor catalysts in aromatic thiol assays, these compounds exhibit high GPx activity when GSH is used as the cosubstrate. The poor catalytic activity of ebselen analogues in the presence of aromatic thiols such as PhSH and 4-Me-C(6)H(4)SH can be ascribed to the undesired thiol exchange reaction that takes place at the selenium center due to SeO nonbonding interactions. To understand the effects of different peroxides on the catalytic activities, we have determined the initial rates at various concentrations of GSH and peroxides. These data suggest that the nature of peroxide has little effect on the catalytic efficiencies, although the initial reaction rates observed with hydrogen peroxide were found to be higher than that with tBuOOH and Cum-OOH. In contrast to the effect of peroxides, the nature of thiols appears to have a dramatic effect on the catalytic activity of ebselen and its related derivatives.     

Synthesis and reactions of some heterocyclic azacyanines

The one-step reaction of some amino-substituted heterocycles with diiodomethane to give azacyanines is reported. This useful reaction is of wider application than initially reported and includes the synthesis of new substituted pyrido-, isoquino-, benzimadazo-, and benzothiazoazacyanines 7. Furthermore, treatment of these azacyanines with base generally affects a facile opening of the dihydrotriazinium ring resulting in the formation of new heterocycles 10, 11, and 12, which would be difficult to prepare by other means. This reaction takes an additional direction in the case of halo-substituted azacyanines 7b/c/d where treatment with base gives rise to new interesting derivatives of dipyridotriazines 14b/c/d.     

Synthesis,antimicrobial evaluation,and docking studies of some novel benzofuran based analogues of chalcone and 1,4-benzodiazepine

A series of novel {5-[4-hydroxy-3-(4-phenyl-2,3-dihydro-1H-benzo[b][1,4]diazepin-2-yl)benzyl]- benzofuran-2-yl}(phenyl)methanones (5a–5g) were prepared by the condensation of (E)-3-{5-[(2- benzoylbenzofuran-5-yl)methyl]-2-hydroxyphenyl}-1-phenylprop-2-en-1-one (chalcone) (4a) with various substituted o-phenylene diamines in the presence of oxalic acid as catalyst. The structures of all compounds were characterized by FTIR, ¹H NMR, ¹³C NMR, and MS. The representative examples were screened in vitro for antimicrobial activity. Among all compounds 4g and 5g showed potent antibacterial activity, 4b and 5g showed good antifungal activity. The data was further compared with structure based investigations using docking studies with the crystal structure of adenosine-5'-(β,γ-imido)triphosphate (2ONJ) from Staphylococcus aureus for antibacterial activity and trypsin (1FY5) protein from Fusarium oxysporum for the antifungal activity. The score values estimated by genetic algorithm were found to have a good correlation with the experimental inhibitory potencies.     

Synthesis of some acylated 2-pyrazoline and chalcone derivatives

α-Haloesters containing the chalcone structure and α-haloamides containing the pyrazoline ring have been synthesized by reaction of substituted hydroxy chalcones and pyrazoline derivatives (prepared as reported elsewhere; J Chem 8(4):1574–1581, 2011) with chloroacetyl chloride in dry THF in the presence of Et₃N. The structures of the synthesized compounds were confirmed by IR, ¹H NMR, and (for some compounds) ¹³C NMR spectroscopy.     

Synthesis and characterisation of some new chalcone liquid crystals

A series of new chalcones with four aromatic rings is synthesised and characterised. The chemical structures of chalcones are evaluated by Fourier transform-infrared spectroscopy, elemental analysis, ¹H and ¹³C nuclear magnetic resonance spectroscopic techniques. The compounds were investigated for liquid crystalline properties using differential scanning calorimetry and polarising optical microscopy with hot stage. The results indicate that the formation of mesophase type is dependent on the alkyl chain length at one end of the molecule. Compounds 9a–d with relatively shorter chains show SmA and nematic mesophases, whereas 9e–g exhibit SmC and SmA mesophases. Compound 9h having a cyano group at one end, exhibit SmA and nematic mesophases.     

查儿酮类似物的合成及抗肿瘤活性研究

<正>查尔酮及其衍生物是芳香醛酮发生交叉羟醛缩合的产物,是合成多种天然化合物重要的有机合成中间体[1]。由于其分子结构具有较大的柔性,能与不同的受体结合,因此具有广泛的生物活性,包括:抗肿瘤、抑制和清除氧自由基、抗菌、抗病毒、抗溃疡和解痉等生物活性[2-7],抗过敏[8],除