Synthesis of substituted 4-hydroxy-1H-thieno[2,3-b;4,5-b′]dipyridin-2-ones

Substituted 4-hydroxy-1H-thieno[2,3-b;4,5-b′]dipyridin-2-ones were prepared by the reactions of 3-cyanopyridine-2(1H)-thiones with alkyl 4-chloroacetoacetates and by intramolecular cyclization of alkyl 4-(2-pyridylthio)acetoacetates or alkyl 3-(3-aminothieno[2,3-b]pyridin-2-yl)-3-oxopropionates under the action of bases.     

Palladium-Catalyzed C-H Bond Functionalization of Benzo[1,2-b : 4,5-b′]dithiophene-4,8-dione: A One Step Access to 2-Arylbenzo[1,2-b : 4,5-b′]dithiophene-4,8-diones

The reactivity of benzo[1,2-b : 4,5-b′]dithiophene-4,8-dione in Pd-catalyzed C−H arylation was investigated. Using aryl bromides as aryl source in the presence of carbonate bases in 1,4-dioxane, the mono-C2-arylated benzo[1,2-b : 4,5-b′]dithiophene-4,8-diones were regioselectively obtained. This procedure allowed to introduce both electron-rich and electron-poor aryl substituents on the benzo[1,2-b : 4,5-b′]dithiophene-4,8-dione unit. These conditions were also effective for the coupling with 1-bromonaphthalene, 9-bromophenanthrene as well as aryl bromides bearing synthetically useful nitrile, chloro and methoxy substituents. The photophysical properties of representative arylated compounds have been performed by joint experimental and theoretical studies.     

Benzo[1,2-b:4,5-b′]dithiophene-based conjugated polyelectrolyte for the cathode modification of inverted polymer solar cells

A conjugated polyelectrolyte (CPE) named PBNBr, is prepared by post-quaternizing of poly{4,8-bis(octyloxy)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-9,9-bis(3′-((N,N-dimethylamino)propyl)fluorene-2,7-diyl} (PBN) with bromoethane. The chemical strucutes, electrooptical properties of the PBNBr is fully characterized. As compared with the PBN, the PBNBr exhibit much better methanol solution processibility, and more effectively tuning ability for the work function (W_f) of ITO (W_F bare ITO, ?4.8 eV, W_F of ITO with PBN interlayer, ?4.1 eV, W_F of ITO with PBNBr interlayer ?3.9 eV). The open circuit voltages (V_OC) and power conversion efficiencies (PCEs) of polymer solar cells from the blend film of poly(3-hexylthiophene) (P3HT) and [6,6]-phenylC₆₁-butyric acid methyl ester (PC₆₁BM) with PBN and/or PBNBr modified ITO as cathode are respectively increased about 27% and 120% in contrast to those for the control devices with bare ITO as cathode. And PCEs of 4.21% and 4.53% are achieved in the PSCs with PBN and/or PBNBr modified ITO as cathode.     

Synthesis and characterization of NLO chromophore with benzo [1,2-b:4,5-b′]dithiophene unit as π-electron bridge

A novel chromophore BDT–TCF with benzo[1,2-b:4,5-b′]dithiophene (BDT) unit as electron bridge was synthesized and characterized by UV–vis, NMR spectroscopy, and thermal analysis. It is the first time that BDT unit was introduced into NLO materials. The chromophore showed excellent solubility in most common solvents, and good thermal stability for practical applications. The second order nonlinear optical effect was measured by hyper Rayleigh scattering method. The diagonal hyperpolarizability β_zzz of BDT–TCF was 8.2 × 10^?28 and 9.3 × 10^?29 esu in THF solvent and in PMMA polymer matrices, respectively. The potential NLO response indicates that BDT unit is a promising π-electron bridge and an excellent candidate for nonlinear optical devices.     

Mild and efficient Winterfeldt oxidation of 1,2,3,4-tetrahydro-γ-carbolines for the synthesis of dihydropyrrolo[3,2-b]-quinolones and pyrrolo[3,2-b]quinolones

The Winterfeldt oxidation (NaOH, DMF, air, rt) of substituted 1,2,3,4-tetrahydro-γ-carbolines has been developed, which provides a convenient and efficient method for the synthesis of the corresponding dihydropyrrolo[3,2-b]quinolones in moderate to excellent yields (38-94%). The generality and substrate scope of this reaction are explored and a possible mechanism is proposed. The results imply that electron-withdrawing groups on N2 of tetrahydro-γ-carbolines and N5-H are necessary. The synthesis of 5 or 7-substituted pyrrolo[3,2-b]quinolones in near quantitative yields was also achieved through deprotection and aromatization of N1-Boc-dihydropyrrolo[3,2-b]quinolones.     

Synthesis and Some Transformations of Derivatives of Pyrido[3,2-b]indole (δ-Carboline)

The reactions of 2-dimethyliminomethyl-3-(p-nitrophenyl)aminoindole chloride with compounds with an active methylene center have been studied. A series of derivatives of -carboline have been synthesized. By the reaction of 3-ethoxycarbonyl-2-methyl-1-p-nitrophenylpyrido[3,2-b]indolinium chloride with the diethyl acetal of DMF the corresponding 2-dimethylaminovinyl derivative was synthesized which was converted into 5-p-nitrophenyl-1-oxo-1,10-dihydropyrano[3',4':5,6]pyrido[3,2-b]indol-5-ium chloride in the presence of acid.     

Synthesis of 11H-Indeno[1,2-b]quinolines via the Friedliinder Reaction

The nine new 11H-indeno[1,2-b]quinolines were synthesized in high yield with sodium ethoxide as a catalyst via the Friedlander condensation reaction, The possible reaction mechanism was proposed.     

Synthesis of Novel Biologically Active s-Triazolo[3,4-b]-1,3,4-thiadiazole Derivatives

Heterocycles bearing a symmetrical triazole or 1,3,4-thiadiazole ring system are reported to show a broad spectrum of biological activities.[1,2] The 1,2,4-triazole nucleus has been recently incorporated into a wide variety of therapeutically interesting drugs including H1/H2 histamine receptor blockers, cholinesterase active agents, CNS stimulants, antianxiety and sedatives[3] Coumarins are nowadays an important group of organic compounds that used as bactericides, fungicides,anti-inflammatory, anticoagulant, anti-HIV and antitumour agents.[4,5] Keeping in view the biological importance of the above mentioned heterocyclic compounds and in continuation of our search for biologically active nitrogen and sulphur heterocycles, a series of s-triazolo[3,4-b]-1,3,4-thiadiazole derivatives was synthesized.     

An unexpected reaction of cyanothioacetamide： Novel preparation of pyrazolo[3,4-b]-pyridine derivatives under MWI

An unexpected multi-component reaction of cyanothioacetarnide with aldehyde and aminopyrazole under MWI was reported. Through this reaction, a series of pyrazolo[3,4-b]-pyridine derivatives was prepared in high yields via simple operational procedure.     

Synthesis of Bisindolylindeno[1,2-b]quinoxaline and Bisindolylindeno[3,4-b]pyrazine with Poly(N,N′-dibromo-N-ethylnaphthyl-2,7-disulfonamide)

Poly(N,N′-dibromo-N-ethylnaphthyl-2,7-disulfonamide) (PBNS) as novel reagent was synthesized. Bisindolylindeno[1,2-b]quinoxaline and bisindolylindeno[3,4-b]pyrazine derivatives were synthesized in a simple and efficient method from the three-component condensation reaction of indole, indane-1,2,3-trione, and diamine aromatic compounds by PBNS under solvent-free conditions at 80 °C in good to excellent yields, short reaction times, and a simple procedure for new derivatives.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications^® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis of derivatives of imidazo[4,5-b]pyridine:Novel sulfur contained side chains for macrolide antibiotics

Two series of novel derivatives of imidazo[4,5-b]pyridine were synthesized.These compounds could be used as side chains of semisynthesised ketolide antibiotics.The side chains have free amine group which can attached to ketolide core.Macrolides with this kind of side chains will show obvious activities against erythromycin-resistant strains.The structure of the side chains was confirmed by ~1H,~(13)C NMR,MS,HMBC spectra.     

Microwave-assisted synthesis of fused pyrazolo[3,4-b]pyrazines by the reaction of ortho-aminonitrosopyrazoles and cyclic β-diketones

Novel fused pyrazolo[3,4-b]pyrazines 3 were prepared by assisted microwave cyclocondensation reaction of ortho-aminonitrosopyrazoles 1 and cyclic β-diketones 2 in dimethylformamide. This protocol provides a simple procedure for the synthesis of the title compounds with the advantages of easy work-up, mild reaction conditions and good yields.     

Synthesis of derivatives of imidazo[4,5-b]pyridine： Novel sulfur contained side chains for macrolide antibiotics

Two series of novel derivatives of imidazo[4,5-b]pyridine were synthesized. These compounds could be used as side chains of semisynthesised ketolide antibiotics. The side chains have free amine group which can attached to ketolide core. Macrolides with this kind of side chains will show obvious activities against erythromycin-resistant strains. The structure of the side chains was confirmed by ^1H, ^13C NMR, MS, HMBC spectra. 2007 Ping Sheng Lei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

Synthesis and optoelectronic properties of a novel molecular semiconductor of dithieno[5,6-b:11,12-b0]coronene-2,3,8,9- tetracarboxylic tetraester简

A facile procedure for the synthesis of dithieno[5,6-b:11,12-b0]coronene-2,3,8,9-tetracarboxylic tetra(2-ethylhexyl)ester(DTCTTE-EH) from readily available perylene-3,4,9,10-tetracaroboxylic dianhydride is described. The electronic properties of DTCTTE-EH were elucidated on the basis of UV–vis spectra, emission spectrum and electrochemical measurement, which demonstrate that DTCTTE is a new class of components for promising semiconducting materials.     

Synthesis and Crystal Structure of 5-Methoxy- butyrolacto[3,4-b]-1-N-cyclohexylaziridine

1 INTRODUCTION The study of aziridine derivatives has been an ac-tive area in organic chemistry due to their interestingreactive properties and special structures[1～3]. Aziri-dine compounds contain unique nitrogen skeleton ofthree-membered heterocycle, which is widely presentin many natural products. They have been used toobtain a variety of biologically important moleculessuch as amino acids, amino alcohols, alkaloids, andβ-lactam antibiotics[2～4]. Although the synthetic routesto azir…     

Synthesis of 11H-Indeno[1,2-b]quinolines via the Friedlnder Reaction

The quinoline nucleus occurs in several natural compounds (cincona alkaloids) andpharmacologically active substances displaying a broad range of biological activity1.The biological activity of quinoline compounds has been found to possess antiasthmatic,an…     

Synthesis and Herbicidal Activity of 2-Benzoyliminopyrimido[3,2-b]-1 2,4-Thiadiazolines

SincethesynthesisandherbicidalactivityofDPX-4l89wasreportedinl98o,awidevarietyofsulfonylureaswithimprovedselectivityand/oreffectivenesshavebeendeveloped'-'.Inacontinuingstudyonthesynthesisandherbicidalactivityofthiophenesulfonylureaandsubstitutedbenzenesulfonylureaderivatives'-',wehavefoundthatsulfonylureaherbicideshaveexcellentherbicidalactivityagainstawiderangeofweeds,butmostofthemwerenotselectivelyactiveherbicides.Inthispaperwedescribethesynthesisandherbicidalactivityofthirteen3-benzoly-l-…     

Synthesis and antitumor activity of α-aminophosphonates containing thiazole[5,4-b]pyridine moiety

A new procedure is developed for the synthesis of α-aminophosphonates containing thiazole[5,4-b]pyridine moiety from conveniently available starting materials. The target compounds were characterized by infrared, (1)H NMR, (13)C NMR, (31)P NMR, mass spectrometry and elemental analysis. The newly synthesized compounds were evaluated for their anticancer activities against PC-3, Bcap-37, H460 cells in vitro by the MTT method. Compounds 3b and 3f are highly effective against PC-3, Bcap-37 cells and good to H460 cells. Further study is necessary to find out the potential antitumor activities.     

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.     

A useful ring transformation route to novel thiazepino[7,6-b]indoles from monochloro-β-lactam-fused 1,3-thiazino[6,5-b]indoles,analogues of cyclobrassinin

The Staudinger ketene-imine cycloaddition reactions of cyclobrassinin phytoalexin analogues 2-aryl-4,9-dihydro-1,3-thiazino[6,5-b]indoles with chloroacetyl chloride as a ketene source were investigated under different conditions. Both β-lactam ring formation and the N-chloroacetylation of the indole moiety took place. The indole N-chloroacetyl group can be easily removed by treatment in the presence of silica gel in methanol at reflux temperature. The selective β-lactam formation can be also achieved in certain cases under milder Staudinger conditions. The treatment of azeto[2,1-b]thiazino[6,5-b]indole-1-one derivatives with sodium ethoxide in ethanol provided the novel thiazepino[7,6-b]indole ring systems in a one-step ring transformation. The structures of the new ring systems were determined by means of IR and NMR spectroscopy.