Synthesis and antiviral bioactivity of novel chalcone derivatives containing purine moiety

A series of novel chalcone derivatives containing purine group was synthesized and evaluated for their antiviral activities against cucumber mosaic virus and tobacco mosaic virus. Compound 3o exhibited remarkable antiviral activities and strong combining capacity to tobacco mosaic virus coat protein.     

Synthesis of some Mannich base derivatives and their antimicrobial activity study

A series of 2-(phenyl)-2-(morpholin-4-yl)-N-phenylacetamide I–VII were synthesized by Mannich base method. Synthesized compounds I–VII were confirmed by IR, ¹H NMR, ¹³C NMR, mass and elemental analyses. Synthesized compounds I–VII were screened for antibacterial activity against various bacterial strains and compared with standard Ciprofloxacin at concentration 100 μg/mL and for antifungal activity against various fungal strains and compared with Clotrimazole at concentration 100 μg/mL; particularly 3-(4-chlorophenyl)-3-(morp holin-4-yl)-N-phenylpropanamide lll that has high antibacterial activity against Streptococcus epidermidis was compared with standard Ciprofloxacin.     

Antioxidant and α-Glucosidase Inhibitory Compounds of Centella Asiatica

Centella asiatica, as known as Pegagan was previously reported to have anti-hyperglycemic effects in animal diabetic model rats. However, its α-glucosidase activity in vitro assay not yet reported. Our goal in this study is to isolate and identify active compounds as α-glucosidase inhibitor and antioxidant from aqueous ethanol 70% (v/v) extract of C. asiatica. The extract was partitioned by n-hexane, EtOAc, and n-butanol sequentially. Among the fractions tested, EtOAc fraction was showed the highest antioxidant and α-glucosidase inhibitory activities with an IC₅₀ values of 45.42 and 73.17 μg/mL, respectively. The antioxidant activity was conducted by determination of DPPH radical scavenging activity, whereas α-glucosidase inhibitory activity was determined against yeast α-glucosidase. Furthermore, isolation of the ethyl acetate extract yielded two active compounds, which were identified as kaempferol (1) and quercetin (2). Both of the compounds showed good yeast α-glucosidase inhibitory activity with IC₅₀ values of 16.50 and 21.61 μg/mL, respectively. In addition those compounds also could scavenge DPPH radical activity with IC₅₀ values of 9.64 and 11.97 μg/mL, respectively. Due to its ability in reducing α-glucosidase activity and scavenging free radical activity, the C. asiatica appears to be a potential as a good resource for future development of antioxidant and antidiabetic drug.     

Synthesis and biological evaluation of novel 1,2,4-triazole containing 1,2,3-thiadiazole derivatives

A series of novel 1,2,4-triazoles containing 1,2,3-thiadiazole derivatives were designed and synthesized. Their structures were confirmed by melting points, IR, 1H NMR, and elemental analysis and ESI-MS or HRMS. Preliminary bioassays indicated that these compounds exhibited very good insecticidal activity against Aphis laburni at 100 μg/mL, with mortality no less than 95%. Compounds 6a, 6c, 6f, 61 showed higher curative activity against TMV and compound 6h showed a higher induction effects against TMV in vivo at 100 μg/mL. Collectively, our data demonstrate a new strategy for control of insects and viruses.     

Synthesis,biological evaluation and Structure Activity Relationships (SARs) study of 8-(substituted)aryloxycaffeine

A series of 8-(substituted)aryloxycaffeine were prepared from 8-bromocaffeine and (substituted)phenols by modified Ullmann reaction. In vitro antibacterial activity, inhibitory activity on topoisomerase II and pharmacological activities were evaluated for the synthesized 8-(substituted)aryloxycaffeine. Among the synthesized compounds, 8-(5-chloropyridin-3-yloxy)caffeine (3k) showed strong inhibitory activity (MIC = 15.6 μg/mL) against the tested gram negative (−) bacteria Salmonella enteritidis. 8-(quinolin-8-yloxy)caffeine (3g) showed the strongest inhibitory activity against topoisomerase II. And the compounds 8-(6-methylpyridin-2-yloxy)caffeine (3j) and 8-(3-chloro-6-(trifluoromethyl)pyridin-2-yloxy)caffeine (3m) showed analgesic effect without the central nervous system stimulation.     

Antimicrobial and anti-inflammatory activities of Piper porphyrophyllum (Fam. Piperaceae)

The crude extracts and isolated compounds of Piper porphyrophyllum (Piperaceae) were evaluated for antibacterial and anti-inflammatory activities. The ethyl acetate extract and 3′,4′,5,7-tetramethoxyflavone exhibited the highest activity against Staphylococcus aureus giving values of MIC = 62.5 and 250 μg/mL, respectively. 5-Hydroxy-7-methoxyflavanone and 4′,5-dihydroxy-3′,7-dimethoxyflavone were active against Pseudomonas aeruginosa, both with MIC value 125 μg/mL. The hexane extract and 4′,5-dihydroxy-3′,7-dimethoxyflavone gave the highest anti-inflammatory activity in in vitro quantitative lipoxygenase inhibition assay with inhibitory activity of (IE) 99.72% and 91.81%, respectively.     

Synthesis and investigations of mixed-ligand lanthanide complexes with N,N′-dipyrrolidine-N′′-trichloracetylphosphortriamide,dimethyl-N-trichloracetylamidophosphate, 1,10-phenanthroline and 2,2′-bipyrimidine

Coordination compounds with general formula [Ln(L¹)₃phen], where Ln = Nd, Eu, Er, Yb, HL¹ = N,N′-dipyrrolidine-N′′-trichloracetylphosphortriamide, phen = 1,10-phenanthroline; [Ln(L¹)₃bpm], where Ln = La, Nd, Eu, Gd, Er, Y, bpm = 2,2′-bipyrimidine and [{Ln(L²)₃}₂(μ-bpm)], where Ln = La, Nd, Eu, Gd, Er, Y, HL² = dimethyl-N-trichloracetylamidophosphate have been synthesized and characterized by means of IR and UV–Vis spectroscopy. Crystal structures of [Nd(L¹)₃phen] (1), [Nd(L¹)₃bpm] (2) and [{Nd(L²)₃}₂(μ-bpm)] (3) have been determined. It was found, that in the deprotonated form the phosphoryl ligands (L¹)^? and (L²)^? are coordinated to the neodymium atoms in a bidentate manner via the oxygen atoms of the phosphoryl and the carbonyl groups with formation of six-membered metallocycles. In the case of compounds 1 and 2 the 1,10-phenanthroline (or 2,2′-bipyrimidine) molecules are coordinated to the metals in a bidentate manner via the nitrogen atoms. In contrast 2,2′-bipyrimidine acts in the bidentate-bridge mode forming binuclear complex 3. Variable-temperature magnetic susceptibility measurements of 3 and [{Gd(L²)₃}₂(μ-bpm)] (4) reveal a weak antiferromagnetic interaction between the two magnetic centres, whereas in the case of [{Eu(L²)₃}₂(μ-bpm)] (5) the presence of spin–orbit coupling leads to a deviation from the Curie and Curie–Weiss laws.     

Synthesis and anti-inflammatory and antimicrobial activities of some novel 2-methylquinazolin-4(3H)-one derivatives bearing urea,thiourea and sulphonamide functionalities

A variety of novel 2-methylquinazolin-4(3H)-one derivatives (1–29) bearing urea, thiourea and sulphonamide functionalities at position 3 of biological interest have been synthesized and screened for their anti-inflammatory (TNF-α and IL-6) and antimicrobial activities (antibacterial and antifungal). “Biological evaluation study revealed that the compounds 3, 4, 6, 9, 16 and 18 were found to have promising anti-inflammatory activity (up to 62–84% TNF-α and 73–92% IL-6 inhibitory activity) at concentration of 10 μM with reference to standard dexamethasone (75% TNF-α and 84% IL-6 inhibitory activities at 1 μM) and 7, 10, 12, 23, 25 and 28 have antimicrobial activity at MIC of 10–30 μg/mL against selected pathogenic bacteria and fungi.”     

Synthesis and antimicrobial activities of novel quinazolin-4(3H)-one derivatives containing a 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole moiety

A series of novel quinazolin-4(3H)-one derivatives (6a–6y) containing a 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole moiety were designed and synthesized, and their structures were fully characterized by ¹H NMR, ¹³C NMR, HRMS and IR spectra. Among them, the structure of compound 6u was unambiguously confirmed via single crystal X-ray diffraction analysis. The obtained bioassay results showed that compounds 6h, 6k, 6l and 6y had the EC₅₀ (half-maximal effective concentration) values of 34.8, 28.2, 41.5 and 42.5 μg/mL against the phytopathogenic bacterium Xanthomonas oryzae pv. oryzae (Xoo), respectively, which were significantly better than commercial bactericide Bismerthiazol (EC₅₀ = 95.8 μg/mL). Additionally, compounds 6a and 6b exhibited the strong inhibition activity against the pathogen Xanthomonas axonopodis pv. citri (Xac).     

Design, synthesis and antiproliferative activities of novel 5H-pyridazino[4,5-b]indoles

A novel series of 5H-pyridazino[4,5-b]indoles were designed and synthesized in order to find novel potent anticancer compounds.The structures were confirmed by ~1H NMR and MS.Their antiproliferative activities against two cancer cell lines were tested by the MTT method in vitro.Three of compounds (1e,1g,and 1h) exhibited potent antiproliferative activities,especially compound 1h (with IC_(50) values of 5.2μmol/L and 1.9μmol/L against Bel-7402 and HT-1080,respectively).The preliminary structure-activity relationships of 5H-pyridazino[4,5-b]indole derivatives were discussed.     

Abiestetranes A and B,two unique tetraterpenes from Abies fabri

Abiestetranes A (1) and B (2), two unique tetraterpenes formed by Diels–Alder cycloaddition between a lanostane triterpenoid and a monoterpenoid, were isolated from Abies fabri. Their structures were elucidated by extensive analysis of NMR data. The electronic circular dichroism was utilized to assign the absolute configuration of 1. Compounds 1 and 2 showed significant cytotoxic activities against ZR-75-30 tumor cell with IC₅₀ values of 6.26 and 1.63 μg/mL, respectively.     

Anticancer and antimicrobial evaluation of newly synthesized steroidal 5,6 fused benzothiazines

A series of new 5α-cholestano [5,6-b] benzothiazines (4–6) has been synthesized by the reaction of 5α-cholestan-6-one (1–3) with 2-aminothiophenol in the presence of iodine. The structures of newly synthesized compounds have been established on the basis of spectral and analytical data. Compounds (1–6) were screened for in vitro anticancer activity against the human cancer cell lines; SW480 (colon adenocarcinoma cells), A549 (lung carcinoma cells), HepG2 (hepatic carcinoma cells) and HeLa (cervical cancer cells) using MTT assay during which the products (4–6) showed marked increase in anticancer activity and in particular, compound 6 showed IC₅₀ = 13.73 μmol L⁻¹ against HeLa cells, being more effective than Doxorubicin against the same cells. Compounds 4 and 6 also showed minimum IC₅₀ of 15.83 μmol L⁻¹ and 16.89 μmol L⁻¹ against HepG2 and A549 cells, respectively. Compounds (1–6) were also tested for in vitro antimicrobial activity against different bacterial as well as fungal strains during which newly synthesized compounds (4–6) were found more potent than starting compounds (1–3). Compound 4 was found to be more potent than the reference drug, Chloramphenicol, in the case of Escherichia coli while compound 5 was found almost equally potential antifungal agent against P. marneffei in comparison with the reference drug, Nystatin.     

Molecular spin ladders self-assembly from [Ni(dmit)2]− building blocks: Syntheses,structures and magnetic properties

Two ion-pair compounds, consisting of 1-(4′-R-benzyl)pyridinium ([RBzPy]⁺, R = NO₂ (1) and Br (2)) and [Ni(dmit)₂]⁻ (dmit²⁻ = 2-thioxo-1,3-dithion-4,5-dithiolato), have been synthesized and structurally characterized. The anions of [Ni(dmit)₂]⁻ stack into dimers, which further construct into two-leg ladder through terminal S⋯S interactions in 1, lateral S⋯S interactions in 2. The weak H-bonding interactions of C–H⋯S were observed in 2, while only weak van de Waals interactions between anion and cations in 1. The magnetic susceptibilities measured in 2–300 K indicate AFM exchange interaction domination both two compounds. A peculiar magnetic transition at ∼100 K was observed in 1. An AFM ordering below ∼11 K was found in 2, and the best fit to magnetic susceptibility above 45 K in this compound, using a dimer model with s = 1/2, give rise to Δ/k_B = 36.1 K, zJ = −0.91 K, C = 3.2 × 10⁻³ emu K mol⁻¹ and χ₀ = −4.0 × 10⁻⁶ emu mol⁻¹ with g of 2.0 fixed.     

Thiazolylhydrazone dervatives as inhibitors for insect N-acetyl-β-d-hexosaminidase and chitinase

Insect chitinase and N-acetyl-β-d-hexosaminidases (Hex) are potential targets for developing new pesticides. Here, a series of thiazolylhydrazones I (with substituted group R₁ at N3) and II (with substituted group R₁ at N2) were designed, synthesised and evaluated as competitive inhibitors of OfHex1 and OfChi-h, from the agricultural pest Ostrinia furnacalis. Derivatives I-3d and II-3d, with phenoxyethyl group at R₁, demonstrated the best inhibitory activities against OfHex1 and OfChi-h. Molecular docking analysis indicated that the branched conformation compound II-3d (K_i = 1.5 μmol/L) formed more hydrogen bonds with OfHex1 than the stretched conformation compound I-3d (K_i = 5.9 μmol/L). The differences in compounds’ binding conformations with OfChi-h explained differences in inhibitory activity of compounds I-3d (K_i = 1.9 μmol/L) and II-3d (K_i = 4.1 μmol/L). This work suggests a novel scaffold for developing specific Hex and Chi-h inhibitors.     

Synthesis,molecular and supramolecular structures,electrochemistry and magnetic properties of two macrocyclic dicopper(II) complexes: Microporous supramolecular assembly

Synthesis, molecular and supramolecular structures, electrochemistry and magnetic properties of two diphenoxo-bridged dicopper(II) compounds [Cu^II₂L(H₂O)(ClO₄)]·ClO₄·2H₂O (1) and [Cu^II₂L(N₃)₂]·2H₂O (2) derived from a tetraimino diphenolate macrocyclic ligand H₂L, obtained on [2+2] condensation of 4-methyl-2,6-diformylphenol and 2,2′-dimethyl-1,3-diaminopropane, are presented. Supramolecular structure of both 1 and 2 are three-dimensional resulting from hydrogen bonding interactions. Interestingly, the 3-D self-assembly of 2 contains micropores having the dimension of 0.35 nm. Electrochemical analyses reveal that both of these compounds exhibit two-step couples in the reduction window. Variable-temperature (2–300 K) magnetic susceptibilities measurements of the two compounds reveal that the metal centers in both of the complexes are coupled by strong antiferromagnetic interactions with J values (H = ?JS₁·S₂) ?776 and ?836 cm^?1 for 1 and 2, respectively.     

Development of a headspace-gas chromatography (HS-GC-PID-FID) method for the determination of VOCs in environmental aqueous matrices: Optimization,verification and elimination of matrix effect and VOC distribution on the Fortaleza Coast,Brazil

An analytical protocol combining a headspace technique with gas chromatography and detection by photoionization detector and flame ionization detector (HS-GC-PID-FID) was developed. This procedure was used to measure volatile organic compounds (VOCs) in environmental aqueous matrices and was applied in determination of VOCs on the coast of Fortaleza, Brazil. At optimum operating conditions, analytical figures of merit such as linearity (R ranged from 0.9983 to 0.9993), repeatability (5.62 to 9.63% and 0.02 to 0.19% for the quantitative and qualitative analyses, respectively), detection limits (0.22 to 7.48 μg L⁻¹) and sensibility were estimated. This protocol favors a fast sampling/sample preparation (in situ), minimizes the use of laboratory material, eliminates the matrix effect from environmental samples, and can be applied to river, estuarine and oceanic waters. The advantage of detectors in series is that a low sensitivity in detection in one is compensated by the other. Toluene was the most abundant VOC in the studied area, with an average concentration of 1.63 μg L⁻¹. It was followed by o-xylene (1.15 μg L⁻¹), trichloroethene (1.08 μg L⁻¹), benzene (0.86 μg L⁻¹), ethylbenzene (0.74 μg L⁻¹), carbon tetrachloride (0.55 μg L⁻¹), m/p-xylene (0.48 μg L⁻¹) and tetrachloroethene (0.46 μg L⁻¹), compounds which are very commonly detected in urban runoff from most cities. The results of the VOC distribution showed that port activity was not the main source of VOCs along the Fortaleza Coast, but that the contribution from urban runoff seemed more significant.     

Pseudoalteromone A: a novel bioactive ubiquinone from a marine bacterium Pseudoalteromonas sp. CGH2XX (Pseudoalteromonadaceae)

A novel ubiquinone derivative, pseudoalteromone A (1), possessing a 9C nor-monoterpenoid moiety was produced from a marine bacterium Pseudoalteromonas sp. CGH2XX. This bacterium is originally isolated from a cultured-type octocoral Lobophytum crassum. The structure of ubiquinone 1 was established by spectroscopic methods. Pseudoalteromone A (1) exhibited significant cytotoxicity toward the MOLT-4 (human acute lymphoblastic leukemia, IC₅₀ = 3.764 μg/mL) cells and displayed a significant inhibitory effect (inhibition rate 45.1%) on the release of elastase by human neutrophils at a concentration of 10 μg/mL.     

Synthesis,structures and magnetic properties of two hexanuclear complexes

The reaction of salicylaldoxime (H₂salox) with Mn(ClO₄)₂ · 6H₂O, NaN(CN)₂ and NEt₃ in MeOH affords a Mn^III₆ hexanuclear complex of [Mn₆O₂(salox)₆(MeOH)₆(NCNCONH₂)₂] (1), while reaction of H₂salox with MnCl₂ · 4H₂O and NEt₄OH in EtOH affords a Mn^III₆ hexanuclear complex of [Mn₆O₂(salox)₆(EtOH)₄(H₂O)₂Cl₂] (2). Both complexes 1 and 2 contain a [Mn^III₆(μ₃-O)₂]¹⁴⁺ core, which is a known structural type in the family of Mn₆ complexes. Variable temperature magnetic susceptibilities and magnetization measurement of complexes 1 and 2 have been carried out. Exchange interactions of metal centers for complexes 1 and 2 are fitted by a full diagonalization matrix method. The fitting results indicate that both complexes 1 and 2 have the ground-state spin value of S = 4, and the ground state of complex 1 has the much closer energy to low-lying spin states than that of complex 2. Magnetization measurements at 2.0–4.0 K and 10–70 kG confirm that the ground state is S = 4, with significant magnetoanisotropy as gauged by the D value of ?0.82 cm^?1 and ?1.18 cm^?1, for 1 and 2, respectively. The frequency dependence of the out-of-phase component in alternating current magnetic susceptibilities for both complexes 1 and 2 indicates the slow magnetic relaxation of superparamagnetic behaviour with a U_eff of 27.0(1) K and τ₀ = 3.8(2) × 10^?9 s for complex 1, and U_eff of 25.1(6) K and τ₀ = 4.6(1) × 10^?8 s for complex 2.     

Synthesis and biological evaluation of 1,4-pentadien-3-one derivatives containing 1,2,4-triazole

A series of new 1,4-pentadien-3-one derivatives containing 1,2,4-triazole moiety were synthesized. The structures of the synthesized compounds were charactered via ¹H NMR, ¹³C NMR and HRMS. Antibacterial bioassays indicated that some of compounds showed potential antibacterial activities against Ralstonia solanacearum (Rs), Xanthomonas oryzae pv. Oryzae (Xoo) and Xanthomonas axonopodis pv. Citri (Xac). Compounds F₈ and F₁₇ showed good in vitro antibacterial activities against Rs, with the EC₅₀ values of 18.6 and 18.6 μg/mL, respectively, which were better than commercial agent bismerthiazol (55.2 μg/mL). Furthermore, compounds F₁₂ and F₁₅ showed good in vitro antibacterial activities against Xoo, with the EC₅₀ values of 10.9 and 17.5 μg/mL, which were better than commercial agent bismerthiazol (69.3 μg/mL). Moreover, compounds F₂, F₉, F₁₆ and F₁₇ showed good in vitro antibacterial activities against Xac, with the EC₅₀ values of 6.6, 5.4, 7.5 and 7.8 μg/mL, respectively, which were better than commercial agent bismerthiazol (54.9 μg/mL). The effect of compound F₉ on Xac bacterial cell membrane rupture was observed by scanning electron microscopy (SEM). In addition, antiviral bioassays indicated that some of compounds showed excellent protection activities against tobacco mosaic virus (TMV). Compounds F₅ and F₁₅ showed good protecting activity against TMV, with the EC₅₀ values of 108.3 and 105.4 μg/mL, respectively, which were better than commercial agent ningnanmycin (214.7 μg/mL). Microscale thermophoresis (MST) also showed that the binding of compound F₂ to TMV coat protein (TMV-CP) yielded a Kd value of 1.260 ± 0.654 μmol/L, which was very close to ningnanmycin (1.058 ± 0.286 μmol/L). Similarly, the molecular docking studies for F₂ and F₅ with TMV-CP (PDB code: 1EI7, ID: 4QGH) indicated that compounds F₂ and F₅ had partially interacted with TMV-CP.     

Synthesis,structure and magnetic properties of pyrazolate-bridged dinuclear complexes [{M(NCS)(4-Phpy)}2(μ-bpypz)2] (M = Co2+ and Fe2+)

The synthesis and magnetic characterization of pyrazolato-bridged dinuclear complexes [{M(NCS)(4-Phpy)}₂(μ-bpypz)₂] (Hbpypz = 3,5-bis(2-pyridyl)-pyrazole; 4-Phpy = 4-phenylpyridine; M = Co²⁺ (1) and Fe²⁺ (2)) are described together with the X-ray crystal analysis of the cobalt complex. The structure of 1 shows that the desired coordination has been achieved with the cobalt atoms being coordinated to two bpypz to form the dimer. The X-ray diffraction patterns show 1 and 2 to be isomorphous at room temperature. 2 displays a single spin-crossover transition between the [HS–HS] and [LS–LS] states with T_c = 150 K.