Volume 71, Issue 4

Polycrystalline samples of Fe 3− y GeTe 2 (0.08 ≤ y ≤ 0.29) and the solid solutions Fe 3− x − y Ni x GeTe 2 (0.24 ≤ x ≤ 1.32; 0.14 ≤ y ≤ 0.41) were synthesized at 898–973 K in a resistance furnace and characterized by X-ray and neutron powder diffraction with Rietveld analysis (Fe 3 GeTe 2 type, P 6 3 / mmc , a = 402.665(3), c = 1632.820(14) pm for x = 0, y = 0.08). Fe 3 Ge layers with planar FeGe hexagons and additional iron atoms above and below the rings are separated by double layers of tellurium atoms. Fe 3 GeTe 2 is ferromagnetic below T C = 230 K with magnetic moments aligned along the c axis. T C depends on the iron content and decreases with increasing iron vacancies continuously to 153 K in Fe 2.71 GeTe 2 . Further reduction of T C is possible by nickel substitution until magnetic ordering is nearly absent in Fe 1.33 Ni 1.32 GeTe 2 . The suppression of the magnetic ordering is caused by random dilution of the magnetic iron atoms either by vacancies or by non-magnetic nickel atoms.

We have presented a potentiometric urea sensor using an urease/bovine serum albumin (BSA)-poly(3,4-ethylenedioxythiophene)(PEDOT)/Pt electrode. A urea detection sensitivity of 15.2 mV/decade (order of magnitude) has been achieved. BSA trapped in the PEDOT matrix was employed to bond urease molecules on the surface of a BSA-PEDOT/Pt electrode via amide bonds formed between the carboxyl functional groups on the enzyme and the amines on the BSA. The effects of PEDOT thickness, pH value of the urea solution, urease concentration, and temperature on the urea detection sensitivity were also studied. The lifetime of the sensor was studied for a period of 10 weeks, and the average sensing degradation rate was about 9 % per week. This sensor displayed a high selectivity to urea over glucose, KCl, and NaCl.

Two new glycosides, 8- O - β- d -glucopyranosyl-6-methyl-1-carboxylate methyl ester xanthone ( 1 ) and 4′- O - β- d -galactopyranosyl djalonensone ( 2 ), together with four known compounds, 8-hydroxy-6-methyl-9-oxo-9 H -xanthene-1-carboxylate methyl ester ( 3 ), cassionllin ( 4 ), djalonensone ( 5 ) and alternariol ( 6 ), were isolated from the endophytic fungus Penicillium sp. (NO.4) of Tapiscia sinensis Oliv. The structures of compounds 1–6 were elucidated by the analysis of 1D and 2D NMR and HRMS. The cytotoxic activities of these compounds were evaluated against four cancer cell lines, as well as antimicrobial activities against two plant-pathogenic microbes. Compounds 1–6 showed moderate cytotoxicity against the A549 cancer cell line with IC 50 values ranging from 6.8 to 35.8 μg mL −1 and were found to be inactive against three other cancer cell lines MCF-7, Caski and Hep G-2.

Three new bioactive compounds, namely ( S )-tenellic acid B dimethyl acetal ( 1a ), (3 R ,3′ R/S )-isotalarone ( 2 ), and (3 R ,5 R )- cis -5-methyl-3-(2-oxobutyl)-dihydrofuran-2-one ( 3 ), were isolated from the terrestrial fungus Penicillium purpurogenum MM, together with 15 known metabolites: talaroflavone, pestalasin A, altenuene, penicillide, 3′- O -methyl-dehydroisopenicillide, rubralactone, tenellic acid B, diaporthin, butyrolactone 1, butyrolactone-V, 4-hydroxy-2-methoxyacetanilide, ergosterol, ergosterol peroxide, linoleic acid, and glycerol monolinoleate. The chemical structures of the three new compounds were confirmed by extensive one- and two-dimensional NMR and electron spray ionization high-resolution mass spectra measurements and by comparison with literature data. The absolute configurations of the new compounds, and of talaroflavone ( 4a ) and tenellic acid B ( 2b ), were determined by ab initio calculations of ECD, ORD, and NMR data. The antimicrobial and cytotoxic activities of the crude extract and of the isolated compounds were studied using a set of microorganisms and brine shrimp assay, respectively. The isolation and taxonomic characterization of P. purpurogenum MM is reported.

A new gentisic acid derivative named micronyc acid ( 1 ) and a new 1,4-benzoquinone derivative named micronone ( 2 ) have been isolated from the root of Micronychia tsiramiramy together with the known compounds gallic acid ( 3 ), methyl gallate ( 4 ), moronic acid ( 5 ), masticadienolic acid ( 6 ), and masticadienediol ( 7 ). The structures of 1 and 2 were established using MS and NMR. Compound 1 was tested for antiplasmodial activity in vitro against the chloroquine-resistant strain Plasmodium falciparum W2 and displayed moderate antiplasmodial activity in vitro with an IC 50 value of 25.6 μ m . Compounds 1 and its acetyl derivative 1a were also tested for their cytotoxicity against the human cervix carcinoma cell line KB-3-1 and still showed moderate activity.

A tetranuclear copper (II) complex with pyrazole-3,5-dicarboxylate ligands (pdc 3− ), [Me 2 NH 2 ] 4 [Cu 4 (pdc) 4 ], was synthesized using solvothermal and metal oxidation routes and characterized by elemental analysis, infrared, thermogravimetry/differential thermal analysis, and room-temperature magnetic measurements. The structure of the complex was determined by single-crystal X-ray diffraction. It comprises dimethylammonium cations and complex anions containing four Cu 2+ cations. The crystal structure is stabilized by N–H···O hydrogen bonds. In addition, the electrochemical behavior was studied.

A new coordination polymer {[Co 2 (DPDBT) 2 (DCPS) 2 (H 2 O)](H 2 O)} n ( 1 ) [DPDBT = 2,8-di(pyridin-4-yl)dibenzothiophene, H 2 DCPS = 4,4′-dicarboxydiphenyl sulfone], was synthesized under solvothermal conditions. Complex 1 exhibits a 2D structure with two different kinds of binuclear cobalt cluster units. The UV/Vis spectra of 1 and of the ligands were investigated, indicating that complex 1 is a potential wide gap semiconductor material.

A facile, efficient, and practical method for n Bu 4 NI-catalyzed direct C–H amination of benzoxazoles with tertiary amines has been developed. The system could be performed in the absence of metal catalyst and only requires tert -butyl hydroperoxide as oxidant under microwave irradiation. A variety of substituted benzoxazol-2-amines were synthesized with moderate to good yield.

Transparent colorless crystals of Na A 5 [C 6 N 9 ] 2 · 4 H 2 O ( A = Rb, Cs) were obtained by blending aqueous solutions of Na 3 [C 6 N 9 ] and RbF or CsF, respectively, and subsequent evaporation of the water under ambient conditions. Both compounds crystallize in the space group P 2 1 / m (no. 11) with the cell parameters a = 815.56(16), b = 1637.7(4) and c = 1036.4(3) pm, and β = 110.738(12)° for NaRb 5 [C 6 N 9 ] 2 · 4 H 2 O and a = 843.32(6), b = 1708.47(11) and c = 1052.42(7) pm, and β = 112.034(2)° for NaCs 5 [C 6 N 9 ] 2 · 4 H 2 O, respectively. Raman spectra of the title compounds complement our results.

A series of new substituted pyrazoles 2 – 12 have been synthesized. The synthesized compounds are structural analogues of GGT1-DU40 1 , a highly potent and selective inhibitor of protein geranylgeranyltransferase I (GGTase-I) both in vitro and in vivo. The implications of GGTase-I in oncogenesis have highlighted its potential as a cancer therapeutic target. Accordingly, the development of GGTase-I inhibitors has been a subject of much interest. The synthesis of 2 – 12 stemmed from the acetylation or acylation of N-function of amino acids to produce suitably modified amino acids. Meanwhile, the substituted pyrazole subunit originated from the reaction of ethyl nicotinate with γ -butyrolactone followed by condensation of the resultant β -keto lactone with (3,4-dichlorophenyl)hydrazine. The operations of O-alkylation and thioetherification on the resultant intermediate eventually produced the substituted pyrazole fragment. The amidation of the latter with amino acid derivatives finally rendered 2 – 12 in good to excellent yields.

The crystal structure of the 1-benzothiepin derivative meso - 5 is presented. Compound 5 is the first dimeric 1-benzothiepin system.