Synthesis and antiproliferative activities of thioxoflavonoids on three human cancer cells

Two series of fifteen novel thioxoflavonoids 2a-2h and 4a-4g were synthesized from corresponding flavonoids 1a-1h and 3a-3g by reacting with Lawesson’s reagent, respectively. Their in vitro antiproliferative activities were evaluated on a panel of three human cancer cell lines (Hela, HCC1954 and SK-OV-3) using cell counting kit-8 (CCK-8) assay. The results showed that most of the target compounds exhibited moderate to good antiproliferative activities against the three human cancer cell lines. In particular, thioxoflavonoids 2f and 2g showed the strongest antiproliferative activity on all three human cancer cell lines with IC₅₀ values ranging from 3.34 to 4.67 μM, 4f showed the best antiproliferative activity on Hela cells (IC₅₀ 2.30 μM), 2e showed the best antiproliferative activity on HCC1954 cells (IC₅₀ 2.13 μM) and SK-OV-3 cells (IC₅₀ 2.33 μM). The antiproliferative activities may be involved in their antioxidant activity, which can be speculated by their ability to scavenge free radicals and by their capacity of affecting key redox enzymes.     

Studies on organophosphorus compounds: reactions of benzosuberones with 2,4-bis(p-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson's reagent)

6-Arylidene-3-methyl-6,7,8,9-tetrahydro-5H-benzo[a]cyclohepten-5-ones (2a-h), obtained by the condensation of 3-methylbenzocyclohepten-5-one 1 with appropriate aromatic aldehydes, on reaction with Lawesson's reagent in xylene yielded phosphorus containing compounds 3a-h. A number of these compounds showed promising anti-inflammatory activity.     

Unusual reduction of a lactone carbonyl in a Bu3SnCl and Na(CN)BH3 mediated radical cyclization of 3-(o-bromophenoxymethyl)coumarins

3-Chloromethyl coumarin was treated with different substituted 2-bromophenols in the presence of anhydrous potassium carbonate in refluxing acetone to afford a number of 3-(2-bromophenoxymethyl)coumarins 3a-f in 80-95% yield. These were then refluxed with tributyltin chloride and sodium cyanoborohydride in benzene under nitrogen, in the presence of a catalytic amount of azobisisobutyronitrile (AIBN) for 7-10 h to give spiro[chroman-3,3′-(2′H)-benzofurans] 4a-f in 60-75% yields.     

凝聚映象的固有值、固有元及其应用

得到凝聚映象的几个新的固有值的存在定理和几个新的固有值、固有元的全局性定理 ,然后利用我们的结果来研究Урысон算子 A:Aφ(x) =∫Gk(x,y,φ(y) ) dy的固有值、固有函数 ,仅在条件 k(x,y,u)≥a(x,y) up≥ 0 (x,y∈G,u∈ [0 ,+∞ ) ,p>0 )之下 ,得到了它的固有值、固有函数的某种全局特征     

Improved detection of steroids on NH2 layers

Summary Thin-layer chromatography (TLC) using NH₂-modified TLC plates is a reproducible method for the measurement of steroids. The sensitivity of determination of steroids (cortisol, cortisone, testosterone, progesterone) by measuring fluorescence in situ can be increased twofold if chromatograms are dipped into a mixture of hexane-paraffin. Fluorescence is further increased if filters are used, which cut emission wavelengths below 400 nm. Using the modifications described, steroid concentrations of about 5 ng per spot could be accurately determined. The increased sensitivity allows measurement of the plasma levels of cortisol in small laboratory animals such as guinea pigs.     

Quantitative HPTLC analysis of carboxylic acids in wine and juice

The need for quick and specific assay of carboxylic acids in wine and non-fermented beverages is explained. The method developed in this work is based on high performance thin-layer chromatography (HPTLC) followed by densitometric evaluation. Untreated samples, with the exception of red wines which were destained, were directly sprayed onto the cellulose layer. The chromatogram was developed with ethyl acetate-toluene-water-formic acid 60:20:20:15, then stained with xylose-aniline reagent. Densitometric scanning is by absorbance at 546 nm. The method is quick, sensitive, and has a wide dynamic range for the acids analyzed.     

2-吡啶苄基酮-2-喹啉基腙分子基态和激发态碱性的量子化学研究

本文用PPP和HMO分子轨道法对2-吡啶苄基酮-2-喹啉基(?)分子基态和激发态的碱性进行了计算,PPP方法计算结果较好地解释该分子在基态和激发态的碱性变化规律,而HMO方法仅适用于基态较好。     

Beiträge zur Stereochemie der Additionsreaktionen an 3,4,5,6-Tetrahydropyridin-1-oxide. 3. Mitt.: Stereochemie der 1,3-Additionen an alkylsubstituierte 3,4,5,6-Tetrahydropyridin-1-oxide

4-tert-Butyl-3,4,5,6-tetrahydropyridine-1-oxide (1) and 6-Butyl-3,4,5,6-tetrahydropyridine-1-oxide (2) were selected to study the stereochemistry of 1,3-additions (nucleophilic additions) to these unsaturated six membered ring systems. Butylmagnesiumbromide, sodiumboronhydride and potassium cyanide were chosen as reagents. They added axially to1, but yielded mixtures of the two possible stereoisomeres with2.

     

ORGANIC CHELATING REAGENT ON REDOX ADSORPTION OF ACTIVATED CARBON FIBER TOWARDS Au~(3+)

1. INTRODUCTION Activated carbon fibers (ACF) are a comparatively modern form of porous carbon materials with a number of significant advantages over the traditional powder or granular forms. These include high surface area and adsorption capacity, as we…     

Kinetics and mechanism of oxidation of dimethyl sulphoxide by sodium bromate-sodium bisulphite reagent in aqueous medium

Rates of oxidation of dimethyl sulphoxide (DMSO) by HOBr producedin situ from sodium bromate-sodium bisulphite reagent have been studied iodometrically in aqueous medium. The order in [DMSO] is one when [DMSO] < 001 mol dm^-3, fractional when [DMSO] is between 0.01 and 0.5mol dm^-3 and zero when (DMSO) > 0.5 mol dm^-3. Different rate laws are operative under these three conditions though HOBr is the effective oxidizing species in all the cases. A mechanism involving an intermediate four-membered cyclic transition state between DMSO and HOBr (formation constantK), which decomposes in a slow step with a rate constant(k) has been proposed. Thermodynamic parameters for the adduct formation step and activation parameters for the first-order decomposition of the adduct step have been evaluated in the temperature range 308–323 K. Activation parameters have also been determined while the orders in [DMSO] are unity and zero. The reaction product has been identified as dimethyl sulphone (DMSO₂).