Synthesis and fungicidal activity of fluorine-containing phenylimino-thiazolidines derivatives

Nine new fluorine-containing phenylimino-thiazolidines derivatives were prepared. The structures of all compounds were confirmed by ¹H NMR, mass and high resolution mass spectroscopy. The antifungicidal activities of the title compounds on Phytophthoza capsici L., Pyriculazia ozyzae C., Fusazium spp. at 100 ppm were screened.     

Synthesis of Pyrimidine Conjugates with 4-(6-Amino-hexanoyl)-7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine and Evaluation of Their Antiviral Activity

A series of pyrimidine conjugates containing a fragment of racemic 7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine and its (S)-enantiomer attached via a 6-aminohexanoyl fragment were synthesized by the reaction of nucleophilic substitution of chlorine in various chloropyrimidines. The structures of the synthesized compounds were confirmed by ¹H, ¹⁹F, and ¹³C NMR spectral data. Enantiomeric purity of optically active derivatives was confirmed by chiral HPLC. Antiviral evaluation of the synthesized compounds has shown that the replacement of purine with a pyrimidine fragment leads to a decrease in the anti-herpesvirus activity compared to the lead compound, purine conjugate. The studied compounds did not exhibit significant activity against influenza A (H1N1) virus.     

Synthesis, structure and insecticidal activity of some novel amides containing N-pyridylpyrazole

A novel series of amides containing N-pyridylpyrazole were designed and synthesized. All of the compounds were characterized and confirmed by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. The single crystal structure of 9d was determined by X-ray diffraction. The bioassay tests showed that the title compounds exhibited good insecticidal activities against Mythimna separata Walker, diamondback moth and Laphygma exigua Hübner.     

Structure-Based Bioisosterism Design,Synthesis, Biological Activity and Toxicity of 1,2,4-Oxadiazole Substituted Benzamides Analogues Containing Pyrazole Rings

In order to discover pesticidal lead compounds with high activity and low toxicity, a series of novel benzamides substituted with pyrazole-linked 1,2,4-oxadiazole were designed via bioisosterism. The chemical structures of the target compounds were confirmed via ¹H NMR, ¹³C NMR and HRMS analysis. The preliminary bioassay showed that most compounds exhibited good lethal activities against Mythimna separate, Helicoverpa armigera, Ostrinia nubilalis and Spodoptera frugiperda at 500 mg/L. Particularly in the case of Mythimna separate, compound 14q (70%) exhibited obvious insecticidal activity. In addition, compound 14h demonstrated good fungicidal activity against Pyricularia oryae with an inhibition rate of 77.8%, and compounds 14e, 14k, 14n and 14r also showed certain antifungal activities (55.6–66.7%). The zebrafish toxicity test showed that the LC₅₀ of compound 14h was 14.01 mg/L, which indicated that it may be used as a potential leading compound for further structural optimization.     

Synthesis of 1-aryl-3-（3,4-dihydro-2H-chromen-5-yl） ureas as TNF-α inhibitors

A new series of compounds,1-aryl-3-(3,4-dihydro-2H-chromen-5-yl) ureas,have been synthesized and their structures were confirmed by FAB-MS and ~1H NMR.The preliminary pharmacological screening showed that these compounds inhibited TNF-αproduction in lipopolysaccharide (LPS)-stimulated THP-1 cells.     

Terpenoids with potent antimycobacterial activity against Mycobacterium tuberculosis from Trigonostemon reidioides roots

Phytochemical investigation of Trigonostemon reidioides roots led to the isolation of fourteen compounds. These included six new diterpenoids, trigonoreidons A?F (1?6), together with eight known diterpenoids 7?14. The structures of the new compounds were elucidated by spectroscopic techniques and the absolute configuration at the asymmetric carbon was determined by the modified Mosher's method. The structure of trigonoreidon B (2) was confirmed by X-ray crystallographic analysis. The known compounds were identified by comparison of the spectroscopic and physical data with those of reported values. The isolated compounds were evaluated for antimycobacterial activity against Mycobacterium tuberculosis. Among the compounds that exhibited antimycobacterial activity, the diterpenoids rediocide C (12) and rediocide G (14) were the most active compounds, with the MIC value of 3.84 μM.     

Sensory-Guided Identification and Characterization of Kokumi-Tasting Compounds in Green Tea (Camellia sinensis L.)

The chemical substances responsible for the kokumi taste of green tea infusion are still unclear. Here, we isolated the kokumi compound-containing fractions from green tea infusion through ultrafiltration, and the major kokumi compounds were characterized as γ-Glu-Gln and γ-Glu-Cys-Gly (GSH) through ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS). The results indicated that peptides and amino acids were essential compounds in the kokumi-enriched fractions for conducting the sense of kokumi. L-theanine had an enhancing effect on the kokumi taste of green tea infusion, which was confirmed in the sensory reconstitution study. Thus, peptides, especially γ-Glu-Gln and GSH, are the major kokumi compounds in green tea infusion, which has the potential of improving the flavor of tea beverages.     

Synthesis and biological activities of new 1H-1,2,4-triazole derivatives containing ferrocenyl moiety

Some new 1H-1,2,4-triazole derivatives containing ferrocenyl moiety were synthesized in various yields by the condensation of ferrocenecarboxaldehyde with 1-(1H-1,2,4-triazol-1-yl)-3-aryl-2-one in toluene. Their structures of all these new compounds have been confirmed with ¹H NMR, IR, MS and elemental analysis. Their results of bioassay showed that some title compounds exhibited some degree of antifungal and plant growth regulatory activities.     

Isolation and total synthesis of two novel metabolites from the fissurellid mollusc Scutus antipodes

There is almost no information on natural products from gastropods in the order Vetigastropoda and nothing at all for the superfamily Fissurellidae (keyhole and slit limpets), which are only partially protected from predation by their shell. Extraction of the Australian fissurellid Scutus antipodes yielded two new compounds, scutinin A [d-sorbityl hexakis(p-hydroxybenzoate)] and scutinin B [2-ethylhexane-1,3-bis(p-hydroxybenzoate)] that were identified by spectroscopic analysis and their structures confirmed by total synthesis. The compounds were found to have antimicrobial activity but no fish antifeedant activity.     

Synthesis and biological activity of fluorinated 2-amino-4-aryl-3,4-dihydro[1,3,5]triazino[1,2-a]benzimidazoles

The heterocyclic nucleus s-triazino[1,2-a]benzimidazole has been reported to exhibit antibacterial activity. In this study, seven new 3,4-dihydro[1,3,5]triazino[1,2-a]benzimidazole derivatives were prepared via cyclocondensation between 2-guanidinobenzimidazole and fluorine substituted (including trifluoromethyl) benzaldehydes. The structures of all the compounds were confirmed by ¹H, ¹³C NMR and IR spectral data. Spectral data also suggested the existence of various tautomeric forms of the fluorine-containing s-triazino[1,2-a]benzimidazole compounds. The synthesized compounds were also screened for antibacterial and bovine dihydrofolate reductase (DHFR) inhibitory activities. The compound 3g substituted with a 3′,5′-bis(trifluoromethyl)phenyl moiety demonstrated the best antibacterial activity in the series. None of the tested compounds significantly inhibited bovine DHFR.     

Thermal behaviour,surface properties and vibrational spectroscopic studies of the synthesized Co3xNi3−3x(PO4)2·8H2O (0 ≤ x ≤ 1)

Co_3xNi_3−3x(PO₄)₂·8H₂O (x = 1, 0.8, 0.6, 0.4, 0.2, and 0) were synthesized via simple wet chemical reaction and energy saving route method. The final decomposition products of hydrates are corresponding anhydrous tri(cobalt nickel) diphosphates. The metal and water contents of the synthesized hydrates were confirmed by AAS and TG/DTG/DTA techniques, respectively. The observed metal and water contents agree well with the formula of the title compounds. The crystal structures and lattice parameters as well as crystallite sizes of the studied compounds were determined using XRD data. The results from XRD and TG/DTG/DTA techniques confirmed that Co_3xNi_3−3x(PO₄)₂·8H₂O at all ratios were the single phase. The FTIR spectra of studied compounds were recorded and assigned. The thermal behaviours of single and binary tri(cobalt nickel) diphosphate octahydrates were studied for the first time. The morphologies of the studied compounds were investigated by using the SEM technique. The micrographs of all studied compounds exhibited the thin plated morphology. The surface area and the pore size data of anhydrous forms were measured by N₂ adsorption at −190 °C according to the BET method. The anhydrous forms of binary metal phosphate at x = 0.8, Co_2.4Ni_0.6(PO₄)₂, exhibits the highest surface area and expects to improve the catalytic activity.     

Stereochemistry of terpene derivatives. Part 4: Fragrant terpenoid derivatives with an unsaturated gem-dimethylbicyclo[3.1.0]hexane system

Starting from (+)-3-carene 1 several chiral fragrant compounds with the bicyclo[3.1.0]hexane system 4–6 and 10–20 were synthesized. These compounds are structural analogues of naturally occurring fragrant compounds, such as ionones and damascones, and possess either an endo- or an exo-cyclic double bond in the bicyclo[3.1.0]hexane moiety. The absolute configuration of selected products was confirmed by X-ray crystallography and circular dichroism analysis.     

Synthesis and antifungal activity of d-glucopyranosyl ureas and d-glucofurano-imidazolidine-2-ones

A series of N-β-d-glucopyranosyl-N’-substituted phenyl ureas were synthesized by reaction of glucosyl isocyanate with arylamines and glycosamine with aryl isocyanates, and a series of d-glucofurano-imidazolidine-2-ones were obtained via deacetylation of glycosylureas. Although some of the compounds have already been described, most were prepared for the first time in this work. The structures of all the compounds synthesized were confirmed by IR, ¹H NMR, and, in part, by ¹³C NMR. Antifungal activity of the title compounds was determined against four kinds of plant pathogenic fungi, Sclerotinia sclerotiorum, Fusarium graminearum, Fusarium oxysporum, and Bipolaris maydis. Preliminary bioassay indicates that most of glycosylureas had some activity against S. sclerotiorum; for some, the antifungal activity was strong. However, most of the imidazolidine-2-ones had weak antifungal activity.     

Thermoanalytical, spectral and biological study of 4-bromobenzoatozinc(II) complexes containing bioactive organic ligands

New zinc(II) 4-bromobenzoate complex compounds with general formula [Zn(4-BrC₆H₄COO)₂L₂]·xH₂O (where L?=?urea, nicotinamide, phenazone or thiourea, x?=?0?C2) were prepared and characterized by elemental analysis, IR spectroscopy and thermal analysis. The thermal decomposition of hydrated compounds started with dehydration process. During the thermal decomposition, the neutral organic ligand, bis(4-bromophenyl)methanone and carbon dioxide were evolved. The solid intermediates and volatile products of thermal decomposition were proved by IR spectroscopy and mass spectrometry. The final solid product of the thermal decomposition heated up to 800?°C was zinc oxide, which was confirmed by X-ray powder diffractometry. Antimicrobial activity of the prepared compounds was tested against various strains of bacteria, yeasts and filamentous fungi (E. coli, S. aureus, C. albicans, R. oryzae, A. alternata and M. gypseum). It was found that bacterium S. aureus and fungi A. alternata are the most sensitive to the studied compounds.     

Improved synthesis of trans-4-alkylcyclohexane carboxylic acids

Several stereomerically pure amino acid derivatives containing the N-terminal trans-4-alkylcyclohexanoyl fragment were obtained. Hydrogenation of 4-alkylbenzoic acids in the presence of a special Ru-Ni/C catalytic system and isomerization of the resulting mixture of trans- and cis-isomers of 4-alkylcyclohexanecarboxylic acids were used as the key steps. The stereomeric configuration of all compounds was confirmed by ¹H NMR spectroscopy. The compounds obtained possess a broad biological activity potential and are useful intermediates in the synthesis of stereomerically pure modified peptides.     

Synthesis and antibacterial activity of new <Emphasis Type="Italic">N</Emphasis>-substituted 7-amino-4-methyl-2<Emphasis Type="Italic">H</Emphasis>-chromen-2-ones

N-Substituted 7-amino-4-methyl-2H-chromen-2-ones containing one or two functionalized azole or azine moieties were synthesized. The structures of all synthesized compounds were confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy. Some of the synthesized compounds exhibited weak antibacterial activity against Rhizobium radiobacter, Escherichia coli, and Xanthomonas campestris.     

Synthesis and Antibacterial Activity of Novel 5,5′-(Pyridine-2,6-Diyl)bis(4-Arylideneamino-3-Mercapto-1,2,4-Triazole)-Related Derivatives

The reaction of 5,5′-(pyridine-2,6-diyl)bis(4-amino-3-mercapto-1,2,4-triazole) with various aromatic aldehydes in acetic acid yielded the corresponding 5,5′-(pyridine-2,6-diyl)bis(4-arylideneamino-3-mercapto-1,2,4-triazole) derivatives. The structures of the synthesized compounds as well as their intermediates were confirmed by elemental analysis, infrared spectra, ¹H NMR spectra and mass spectra studies. All the synthesized title compounds were screened for their antibacterial activities, and the preliminary results revealed that some of them showed good activities against Escherichia coli and Pseudomonas aeruginosa.     

Synthesis and characterization of biphenyl liquid crystal based on natural molecules and 2(5H)-furanone moiety

Using 4′-hexyloxybiphenyl-4-ol and N-(5-alkoxy-3-bromo-2(5H)-furanonyl) amino acids as reactants, a series of novel biphenyl liquid crystal compounds containing natural molecule moieties, such as menthol, borneol, and amino acids, were synthesized via esterification. The structures of all novel compounds were confirmed by FTIR, ¹H NMR, ¹³C NMR, MS, and elemental analysis, and the liquid crystal properties of target compounds were characterized with DSC, XRD, and POM. The introduction of hexyloxy made the biphenyl esters have a potential to appear in mesomorphic phase and have a higher Tm, and bornyl moiety was more beneficial for the liquid crystal performance than a menthyl unit. Most compounds were mesomorphic phase liquid crystal molecules, and POM and XRD showed that they existed in smectic phase. These researches provide a theoretical basis for the synthesis of biphenyl ester liquid crystal materials via the utilization of 2(5H)-furanone derivates and natural molecules.     

Design and synthesis of novel thiopheno-4-thiazolidinylindoles as potent antioxidant and antimicrobial agents

A novel and convenient synthesis of thiopheno-4-thiazolidinyl indole analogues is presented (IVa-IVi), with the aim of obtaining biologically active compounds. 3,5-disubstituted indol-2-carboxyhydrazides (Ia-If) were allowed to react with 3-acetyl-2,5-dichlorothiophene (II) to yield the corresponding 3,5-disubstituted indol-2-carbohydrazides (IIIa-IIIf). The pre-formed indolecarbohydrazides (IIIa-IIIf) were allowed to react with 2-mercaptoacetic acid or 2-mercaptopropanoic acid to produce thiopheno-4-thiazolidinylindoles (IVa-IVi). This reaction protocol affords a simple, eco-friendly, non-hazardous, easier preparation and high yields. The antioxidant (free radical scavenging, total antioxidant capacity and ferric-reducing antioxidant power) and antimicrobial activities of the synthesised compounds were evaluated. The structures and purity of the products were confirmed by their IR, ¹H NMR, ¹³C NMR and mass spectral and analytical data. Most of the compounds tested showed very significant scavenging, antioxidant and antimicrobial activities. Compounds containing electron donor group (CH₃) at the fifth position of indole exhibit an excellent ferric-reducing activity. The present study suggests that compounds IIIa-IIIb, IIIf, IVa-IVc, IVf-IVi, may serve as promising lead scaffolds for antioxidant and antimicrobial agents.     

Discovery of Quinazoline-2,4(1H,3H)-Dione Derivatives as Potential Antibacterial Agent: Design,Synthesis, and Their Antibacterial Activity

In this paper, we report on the design and synthesis of a novel series of quinazoline-2,4(1H,3H)-dione derivatives as fluoroquinolone-like inhibitors of bacterial gyrase and DNA topoisomerase IV to identify and develop antimicrobial agents to prevent bacterial resistance problems. Their structures were confirmed using spectroscopic analyses (IR, NMR, and EI-MS). The novel quinazoline-2,4(1H,3H)-dione derivatives were evaluated for their antimicrobial activities against Gram-positive and Gram-negative bacterial strains using the Agar well diffusion method to study the antimicrobial activities and compared them with the standard drugs. Most compounds displayed moderate activity. Among the tested compounds, the most promising compounds 13 and 15 provided broad bioactive spectrum against Gram-positive and Gram-negative strains compared to the standard drugs.