Band 77, Heft 1

Entada abyssinica Steud. Ex A. Rich (Leguminosae) is a medicinal plant used traditionally for the treatment of infections. A phytochemical investigation of the methanol extract of E. abyssinica root bark led to the isolation of a new phenanthrene derivative named phenentada ( 1 ), together with seven known compounds (8  S, 13 E )-kolavic acid 15-methyl ester ( 2 ) and 8  S -kolavic acid 15-methyl ester ( 3 ) obtained as mixture, 8  S -kolavic acid 15-methyl ester ( 3 ), 8  S -kolavic acid 18-methyl ester ( 4 ) , 13,14,15,16-tetranorclerod-3-ene-12,18-dioic acid ( 5 ), 1′,26′-bis-[( S )-2,3-dihydroxypropyl] hexacosanedioate ( 6 ), campesterol ( 7 ) and 3- O - β -d- glucopyranosylstigmasterol ( 8 ). Their structures were determined by NMR spectroscopy (1D and 2D), mass spectrometry (HRESIMS) and by comparison with previously reported data. The crude extract and some isolated compounds were evaluated for their in vitro antimicrobial activities by the microdilution method while, the antioxidant activity was evaluated by the DPPH methods. Regarding the antimicrobial activity, the crude extract showed significant inhibitory activities against bacteria strains (MIC 7.81–31.3 μg mL −1 ) and yeasts (MIC 15.6–31.3 μg mL −1 ) whereas all compounds tested exhibited significant activity against Staphylococcus epidermidis. Moreover, compounds 4 , 5 and 6 and the mixture 2/3 showed significant antimicrobial activity on Candida parapsilosis strain (MIC = 3.12 μg mL −1 ), as well as selected antifungal property against candida pathogenic fungi strains. On the other hand, compounds ( 1 ) demonstrated the best bioactivities against Candida albicans and Salmonella enterica with MIC = 3.12 μg mL −1 while the mixture 2 / 3 appeared to have the highest inhibition on gram (+) bacteria strain S. epidermidis with MIC of 0.78 μg mL −1 and compound 5 (MIC = 1.56 μg mL −1 ) against the gram (−) bacteria strain. Furthermore, the SC 50 values measured by the antioxidant test for all samples varied between 47.21 and 52.44 μg mL −1 for DPPH. These results support the traditional uses of E. abyssinica in the management of several diseases including the claim in the skin disease treatment. Additionally, here is reported the first time isolation of a phenanthrene derivative in the Fabaceae family to the best of our knowledge.

The search for antileishmanial plants used in traditional medicine led to the choice of CH 2 Cl 2 –MeOH (1:1) crude extract of the fruits and stem bark of Pentadesma butyracea Sabine (Clusiaceae) which displayed good activity in vitro against Leishmania donovani 1S (MHOM/SD/62/1S) promastigotes during preliminary screening with IC 50 values 5.96 and 26.43 μg mL −1 , respectively. The fractionation of both extracts using flash chromatography yielded active fractions with IC 50 values ranging from 2.71 to 18.88 μg mL −1 . Fourteen compounds ( 1 – 14 ) were isolated from the obtained fractions using successive column chromatographies and their structures were elucidated based on the analysis of their NMR and MS data. Daphnifolin ( 1 ), epicathechin ( 3 ), α-mangostin ( 9 ) and 9-hydroxycalabaxanthone ( 14 ) exhibited potent antileismanial activity against L. donovani 1S (MHOM/SD/62/1S) promastigotes with IC 50 values of 2.01, 9.09, 3.37, and 6.87 μg mL −1 , respectively and good selectivity towards Raw 264.7 macrophage cells (SI > 2.4). Extracts, fractions and some isolates were also assessed in vitro for their antibacterial activity against six bacterial strains [ Salmonella typhi (CPC), Enterobacter cloacae (CPC), Pseudomonas aeruginosa HM801, Staphylococcus aureus ATCC 43300, Streptococcus pneumoniae ATCC 491619, Escherichia coli ATCC 25322] using serial microdilution method. Among the tested samples, the stem bark extract of P. butyracea as well as compounds 2 and 8 showed good to moderate activity against the aforementioned bacterial strains with MIC ≤ 250 μg mL −1 .

A pair of two-dimensional (2D) isostructural coordination polymers (CPs), {[Co(2,3-qldc)(H 2 O)]} n ( 1 ) and {[Mn(2,3-qldc)(H 2 O)]} n ( 2 ), where 2,3-H 2 qldc = quinoline-2,3-dicarboxylic acid, were hydrothermally synthesized and characterized through IR spectroscopy, elemental and thermal analysis, power X-ray diffraction, and single-crystal X-ray diffraction. The results have revealed that the fully deprotonated 2,3-H 2 qldc ligand connects the Co(II)/Mn(II) atoms with a μ 3 -bridge to form a square-wave 2D network, which is further extended into 3D stacks through O–H···O, C–H···O hydrogen bonds and π···π stacking interactions. Topologically, 1 or 2 can be simplified as a 4-connected sql type with a Schläfli symbol {4 4 ·6 2 } and a Shubnikov tetragonal plane net, or as a 3-connected fes type with a Schläfli symbol {4·8 2 } and a Shubnikov plane net. The thermal stability and the solid state fluorescence properties of 1 and 2 were investigated.

Reaction of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene ( 1 ) with phthalimide, quinazolinedione, thiophenole and 4-pyridinethiole led to the formation of the hydrogen-bonded salts, imidazolium phthalimide ( 2 ), imidazolium quinazolinedione ( 3 ), imidazolium thiophenolate ( 4 ) and imidazolium 4-pyridinethiolate ( 5 ), respectively, in good yield. In crystals of 2 , the anion is linked to the imidazolium cation by a C–H···O hydrogen bond, while in 3 and 5 C–H···N hydrogen bonds are observed. In 4 , the imidazolium ion is linked to the anion by C–H···S hydrogen bonds. In compounds 2 , 3 and 5 , the interionic hydrogen bonds are close to linearity, while the interionic hydrogen bond angle in 4 is 148.5(9)°.

The crystal structure of a copper(II) complex of protonated sildenafil, CuCl 3 C 22 H 31 N 6 O 4 S⋅2H 2 O was studied by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P 2 1 / n with the unit cell parameters a  = 15.4292(2), b  = 9.06735(12), c  = 21.1752(2) Å, V  = 2945.48(7) Å 3 , Z  = 4. The Cu atom is coordinated by the sildenafil ligand via the N2 atom of the pyrazolopyrimidine ring and by three chloride anions. Sildenafil is protonated at the methylated N6 atom of the piperazine ring and it is cation ligand with a 1+ charge.

Electrochemical bromination and iodination of some pyrazoles were investigated under constant-current (CC) electrolysis in an undivided electrochemical cell. Anodic oxidation of KX salt produces X 2 in-situ which can be consumed as an expedient electrophile in pyrazoles aromatic electrophilic substitution reactions or may participate in an X–N coupling reaction with electrochemically catalyzed pyrazoles ox to form the halogenated pyrazoles. All reactions proceeded without the need to use any hazardous reagents or catalysts. The reaction conditions are mild and environmentally compatible.

In the present study, a novel series of new furanone-based benzothiazole derivatives ( 4a-j ) were synthesized from 4-(benzo[ d ]thiazol-2-yl)-4-oxobutanoic acid ( 3 ) as potential anticancer agents. In vitro cytotoxicity against three human cancer cell lines (A549, MCF7, and DUI45) revealed substantial activity. Di-substituted compound, 4i emerged as a promising anticancer compound which showed IC 50 values of 7.2 ± 0.5, 6.6 ± 1.4, and 7.3 ± 0.1 µM against A549, MCF7, and DUI45 cell lines, respectively. Four compounds 4c , 4e , 4f , and 4i evaluated for their acute toxicity were found to be non-toxic on the two vital organs (liver and heart). Further, these compounds were found to be more efficient and less hepatotoxic in comparison to standard drug doxorubicin. Molecular docking studies carried out with VEGFR-2 revealed compounds 4a and 4i as potential VEGFR-2 kinase inhibitors. In silico ADME evaluation was carried out to estimate and predict drug-likeness. Compound 4i demonstrated the best ADME parameters. Based on the results of docking analyses, ADME, and in vitro cytotoxicity, compound 4i is identified as the lead compound for further development of anticancer agents.

New N -silylated phthalimides, succinimides, and 1,8-napthalimides were synthesised by reactions of the alkali imides with chlorosilanes in THF. Six different mono-, di-, tri- and tetra-iminosilanes of the type (CH 3 ) 4– n Si(imide) n were obtained and the products analysed with 1 H, 13 C, 29 Si NMR, and Raman spectroscopy. The molecular structures of four imidosilanes have been determined by single-crystal X-ray diffraction. A characteristic structural feature of the compounds is the fact that all intramolecular Si⋯O distances are significantly below the sum of the van-der-Waals radii of silicon and oxygen of 3.62 Å. Experimentally found values for Si⋯O distances range from 2.813 to 3.030 Å. However, there are no significant orbital interactions between silicon and oxygen atoms, as shown by quantum chemical analysis with AIM and NBO methods. The short Si⋯O distances in these molecules are caused by the geometry of the rigid imide group bound to the silicon atom, and there is no evidence for an increase of the coordination number of the Si atoms.

In this work, a novel metal-organic framework (MOF) based on 2,6-di(1 H -imidazol-1-yl)naphthalene (L) and biphenyl-3,4′,5-tricarboxylic acid (H 3 bptc), namely [Co(L)(Hbptc)(H 2 O)] ( 1 ), has been prepared. 1 has a distinct infinite chain structure, further linked together by winding interactions to give the three-dimensional (3D) network structure. 1 was characterized by X-ray crystallography, infrared spectra (IR) spectroscopy, elemental and thermal analysis. Photoluminescence studies revealed that 1 shows a strong emission at 361 nm upon excitation at 290 nm at room temperature. Moreover, 1 can efficiently detect Fe 3+ ions by luminescence quenching.

A practical and efficient synthetic route to construct a variety of 3-arylselenenyl/3-arylthio spiro[4.5]trienones was developed using Selectfluor reagent as a mild oxidant. This reaction proceeds via a sequence of electrophilic cation addition, spirocyclization and dearomatization, then offers an approach to introduce Se/S-centered cation into the C–C triple bonds. The utility of this protocol were justified by the excellent compatibility of a wide range of functional groups, good yields and scalability under mild reaction conditions.

3-Methyl-1-sulfonic acid imidazolium trichlorido copper (II) {[Msim]CuCl 3 } was prepared and used as a new catalyst for the preparation of 5-amino-1H-pyrazole-4-carbonitriles. In this reaction, the pyrazole ring was formed by an anomeric and vinylogous anomeric effect in the structure of the product.

The synthesis and structure of an asymmetrical sila[1]magnesocenophane, featuring a cyclopentadienyl and a tetramethylcyclopentadienyl group, are reported. The compound was obtained as a bis(tetrahydrofuran) adduct and exhibits a slipped sandwich structure in the solid state.