NbCl5 as an Efficient Catalyst for the Synthesis of 1,5-Benzodiazepine Derivatives

1,5-Benzodiazepine derivatives were synthesized in moderate to excellent isolated yields by the condensation reactions of o-phenylenediamine and ketones catalyzed by NbCl₅ under mild conditions using n-hexane as solvent at 50°C. This method is simple and effective with good yields.     

An Efficient Solid Acid Promoted Synthesis of Quinoxaline Derivatives at Room Temperature

Quinoxaline derivatives have been synthesized in a very short time with excellent yields by the condensation of 1,2-diamines with aliphatic or aromatic 1,2-dicarbonyl compounds or benzilmonoxime in the presence of silica sulfuric acid as a very inexpensive solid acid catalyst at room temperature. The recovery and reuse of the catalyst are also satisfactory.     

有效合成5—硝基呋喃烯衍生物

报道了一种有效合成５－硝基呋喃烯衍生物的方法。在常温、弱碱Ｋ２ＣＯ３存在下（ｔｒａｃｅＨ２Ｏ），５－硝基呋喃亚甲基溴化钾盐与芳醛反应，高产率、高立体选择性地得到５－硝基呋喃烯衍生物。     

NbCl5 as an Efficient Catalyst for Chemoselective Synthesis of 1,1-Diacetates Under Solvent-Free Conditions

A mild and efficient method for the chemoselective preparation of 1,1-diacetates catalyzed by NbCl₅(5 mmol%) under solvent-free conditions has been developed. The yields are in the range of 93–98%. This protocol offered several advantages, including low catalyst loading, good yields, short reaction times, and environmentally friendliness.     

室温离子液体促进的5-亚芳基巴比妥酸衍生物的合成

在室温离子液体1-丁基-3-甲基咪唑四氟硼酸盐([bmim]BF₄)存在下, 采用室温研磨和微波辐射的方法, 由芳香醛和巴比妥酸或硫代巴比妥酸经Knoevenagel缩合反应, 制备了相应的5-亚芳基巴比妥酸或5-亚芳烃基硫代巴比妥酸衍生物. 在室温研磨条件下反应2 h, 产率为78%～96%, 在微波辐射功率为160 W时反应20 s, 产率为82%～98%, 产物结构经¹H NMR确证.     

An Efficient One‐pot Synthesis of Pyrazolone Derivatives Promoted by Acidic Ionic Liquid

A new class of pyrazolone derivatives has been isolated in good to excellent yields from the 2:1 condensation reaction between 3‐methyl‐1‐phenyl‐5‐pyrazolone and arylaldehydes in the presence of ionic liquid [HMIM]HSO₄. The compounds were characterised by their IR, NMR spectra, MS and elemental analyses. The important features of the methodology are a wide application range of substrates, higher yields and shorter reaction time.     

Selective and Efficient Deoxygenation of Sulfoxides with NbCl5/Indium System

It has been found that dialkyl, diaryl, and aryl alkyl sulfoxides can be selectively converted to the corresponding sulfides with a NbCl₅/In system in good to excellent yields under mild conditions. Several functional groups (bromo, chloro, methoxy, aldehyde, and vinyl) were tolerated under the reaction conditions.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis of the Cyclopentenylamine Derivatives Promoted by SmI2

The intermolecular reductive coupling of 1,1-diary1-2,2-drcyanoethylenes with cinnamic esters promoted by samarium( Ⅱ）iodide was studied.Functionalized cyclopentenylamine derivatives were prepared in good yields under neutral and mild conditions.     

Novel and Efficient Synthesis of Pyrimidine Derivatives

A new series of 1-alkyl-2-oxo-1,2-dihydro-pyrimidine-5-carboxalic acid amides is described. The reaction of N-((E)-3-(dimethylamino)-2-formylacryloyl) formamidine, an intermediate obtained by Vilsmeier–Haack formylation of acetonitrile with various mono-substituted ureas, provides such compounds in good yields.     

General and Efficient Synthesis of O-Sulfonylhydroxylamine Derivatives

A general and efficient synthetic route to O-sulfonylhydroxylamine derivatives is described. The approach involves acylation of hydroxylamine with benzyl chloroformate to give N-carbobenzoxy hydroxylamine, followed by sulfonation and hydrogenolysis to give products.     

Synthesis of 5-Alkyl- and 5-Phenylamino-Substituted Azothiazole Dyes with Solvatochromic and DNA-Binding Properties

A series of new 5-mono- and 5,5′-bisamino-substituted azothiazole derivatives was synthesized from the readily available diethyl azothiazole-4,4′-dicarboxylate. This reaction most likely comprises an initial Michael-type addition by the respective primary alkyl and aromatic amines at the carbon atom C5 of the substrate. Subsequently, the resulting intermediates are readily oxidized by molecular oxygen to afford the amino-substituted azothiazole derivatives. The latter exhibit remarkably red-shifted absorption bands (λ_abs=507–661 nm) with high molar extinction coefficients and show a strong positive solvatochromism. As revealed by spectrometric titrations and circular and linear dichroism studies, the water-soluble, bis-(dimethylaminopropylamino)-substituted azo dye associates with duplex DNA by formation of aggregates along the phosphate backbone at high ligand–DNA ratios (LDR) and by intercalation at low LDR, which also leads to a significant increase of the otherwise low emission intensity at 671 nm.     

Efficient Synthesis of Substituted Indene Derivatives

An efficient protocol for the synthesis of new functionalized indenes 3 was successfully realized. Thus the coupling reaction of allyl acetate 2 with Grignard reagents in the presence of a catalytic amount of LiCuBr₂ at low temperature afforded pure ethyl 1-alkyl-1H-indenes-2-carboxylate 3 in good yields.     

Quantum-Mechanical and Solvatochromic Characterization of Quercetin

ABSTRACT

Quercetin was subjected to a quantum-mechanical analysis and energetic and electro-optic parameters were evaluated. A solvatochromic study was used to estimate the dipole moment of quercetin in the excited state and to determine the angle between the dipole moments of this molecule in the electronic states responsible for the visible absorption band. The contribution of each type of intermolecular interactions to the total spectral shift experimentally recorded in quercetin solution was also established in this study.     

氯硝柳胺衍生物的合成与结构表征

由氯硝柳胺与1,2-二溴乙烷反应,得到2-(2-溴乙氧基)-5-氯-N-(2-氯-4-硝基苯基)苯甲酰胺,再与乙二醇、二乙二醇、三乙二醇分别反应,得到了三个氯硝柳胺衍生物,其结构由IR1、H NMR和高分辨质谱确证。     

双香豆素类化合物的合成及表征

香豆素是一类具有重要生理活性的天然产物。本文通过4-羟基香豆素的合成,然后与醛缩合,制备了一类具有双香豆素结构的化合物,对其结构通过^1H NMR、IR及元素分析确证并对其波谱学特征予以了讨论。     

Synthesis and Characterization of Chloropentaaryloxycyclotriphosphazene Derivatives

Five chloropentaaryloxycyclotriphosphazene derivatives were synthesized by the reaction of hexachlorocyclotriphosphazene with potassium phenoxide in tetrahydrofuran. A satisfactory yield could be obtained when a 5.1 : 1(KOC ₆ H ₄ R : P ₃ N ₃ Cl ₆ ) molar ratio was used. The new compounds were characterized by IR, ¹H NMR, ³¹P NMR, ¹³C NMR, and ESI-MS, and for two of them by HR-MS.     

Synthesis,Characterization, and Anticancer Effect of Trifluoromethylated Aurone Derivatives

A series of trifluoromethylated aurone derivatives were synthesized, and the structure of 6‐hydroxy‐4‐trifluoromethylated aurone was determined by single crystal X‐ray analysis. Their anticancer activities against leucocythemia (HL‐60) and colorectal adenocarcinoma (HT‐29) were evaluated by the standard MTT method in vitro with 5‐fluorouracil as a positive contrast drug. The results showed that all the (Z)‐trifluoromethylated aurone derivatives had potential anticancer activities.     

A New and Efficient Synthesis of Wedelolactone Derivatives

A new and facile method based on an intermolecular cycloaddition was described for the synthesis of wedelolactone derivatives.     

5-取代氧化呋咱并[3,4-b]吡啶衍生物的合成与表征

以廉价易得的2,6-二氯吡啶为原料,经过硝化、叠氮化、热解环化步骤得到中间体[1,2,5]噁二唑并[3,4-e]四唑并[1,5-a]吡啶-3-氧化物(4b),再与浓硫酸/硝酸钾、甲醇钠和甲胺水溶液反应分别得到5-取代的氧化呋咱并[3,4-b]吡啶衍生物5~7。 研究了化合物4b结构的稳定性,发现其中的氧化呋咱环在强酸性、强碱性和弱碱性条件下较稳定,而吡啶环与叠氮基形成的四唑环结构则不太稳定。