Theophylline as a new and green catalyst for the one-pot synthesis of spiro[benzo[a]pyrano[2,3-c]phenazine] and benzo[a]pyrano[2,3-c]phenazine derivatives under solvent-free conditions

A green, convenient, high yielding and one-pot procedure for the synthesis of novel spiro[benzo[a]pyrano[2,3-c]phenazine] derivatives by domino multi-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, ninhydrine, and malononitrile in the presence of a catalytic amount of 1,3-dimethyl-7H-purine-2,6-dione (theophylline) as an expedient, eco-friendly and reusable solid base catalyst under thermal, microwave irradiation and solvent-free conditions. This procedure has also been applied successfully for the synthesis of benzo[a]pyrano[2,3-c]phenazines.     

Synthesis of novel bis(chromenes) and bis(chromeno[3,4-C]pyridine) incorporating piperazine moiety

Novel bis(2-oxo-2H-chromene) as well as bis(2-imino-2H-chromene) derivatives incorporating piperazine moiety were prepared by the cyclocondensation reaction of bis(2-hydroxybenzaldehyde) with two equivalents of each of the appropriate β-ketoesters or acetonitrile derivatives. The bis(2-imino-2H-chromene-3-carbothioamide) derivative was used as a key synthon for construction of novel bis(3-(4-substituted thiazol-2-yl)-2H-chromen-2-one) derivatives via its cyclocondensation with a series of the appropriate α-halocarbonyl derivatives. Moreover, the bis(2-hydroxybenzaldehyde) reacted with four equivalents of the appropriate acetonitrile derivatives to afford the corresponding bis(3H-chromeno[3,4-c]pyridine) derivatives. Elucidation of the structure of the novel bis(chromenes) bearing piperazine nucleus was established by the spectral data and elemental analyses.     

Amidinoyl isothiocyanates in the synthesis of condensed heterocycles: Preparation of quinazolino[3,4-c][1,3,5]-benzotriazepines and quinazolino[3,4-c][1,2,3,5]-benzotetraazepines

Summary When heated, amidinoyl isothiocyanates (I) with 2-nitrophenyl isothiocyanate cyclize to 4-(2-nitroanilino)quinazolines (II) and after reduction to 2-amino derivatives (III). The latter serve as precursors to derivatives of the title compounds.

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Amidinoylisothiocyanate als Bausteine in der Synthese von kondensierten Heterozyklen. Darstellung von Chinazolino[3,4-c][1,3,5]-benzotriazepinen und Chinazolino[3,4-c][1,2,3,5]-benzotetraazepinen

Zusammenfassung Beim Erhitzen cyclisieren Amidinoyl-isothiocyanate (I) mit 2-Nitrophenyliso-thiocyanaten zu 4-(2-Nitroanilino)chinazolinen (II) und nach Reduktion zu 2-Aminoderivaten (III). Die letztgenannten dienen als Ausgangssubstanzen für Derivate der Titelverbindungen.

     

Convenient synthesis of spiro[indoline-3,4'-pyrano[2,3-c]pyrazole] and spiro[acenaphthyl-3,4'-pyrano[2,3-c]pyrazoles] via fourcomponent reaction

The base promoted four-component reaction of hydrated hydrazine, dimethyl acetylenedicarboxylate, isatines and malononitrile (ethyl cycanoacetate) in ethanol afforded polysubstituted spiro[indoline-3,4‘-pyrano[2,3-c]pyrazoles] and spiro[acenaphthyl-3,4-pyrano[2,3-c]pyrazoles]     

Nicotinic acid-supported cobalt ferrite-catalyzed one-pot synthesis of substituted chromeno[3,4-b]quinolines

One-pot synthesis of substituted chromeno[3,4-b]quinoline derivatives was developed by three-component reaction of aldehydes, dimedone or 1,3-cyclohexadione, and 4-aminocoumarin in the presence of nicotinic acid-supported cobalt ferrite [CoFe₂O₄@SiO₂@Si(CH₂)₃Cl@NA] as a novel magnetic catalyst in chloroform at reflux conditions. Nicotinic acid-supported cobalt ferrite was characterized via Fourier transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and vibrating sample magnetometry. Moreover, the catalyst could be easily recovered by magnetic separation and recycled up to five times without significant loss of its catalytic activity. The products formed in excellent yields over appropriate reaction times under environmentally friendly conditions. High efficiency and easy isolation of the catalyst from products by simple magnetic attraction are some of the considerable advantages of this procedure.     

Synthesis of furo[3,2-c]- and pyrano[3,2-c]quinolines by lanthanide triflate catalyzed imino-Diels-Alder reaction

Imino Diels-Alder reaction of imines with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran proceeded smoothly in the presence of a catalytic amount (0.5 mol %) of ytterbium triflate to afford furo[3,2-c]- and pyrano[3,2-c] quinolines conveniently in high yield.     

Morpholine triflate promoted one-pot,four-component synthesis of dihydropyrano[2,3-c] pyrazoles

A one-pot,four-component reaction of ethyl acetoacetate,hydrazine hydrate,aldehydes,and malononitrile was discussed using Lewis acid catalyst morpholine triflate (MorT) to afford a series of dihydropyrano[2,3-c] pyrazoles,which were generally catalyzed by organic alkalis.Moderate to excellent yields,no chromatographic purification,and evasion of environmentally hazardous solvents in the reaction process make this protocol very useful for academia and industry.     

非经典稠合噻吩: 噻吩并[3,4-c]噻吩研究进展

具有10π-电子的噻吩并[3,4-c]噻吩体系, 由于其非经典的电子结构, 引起了很大的兴趣. 本工作综述了噻吩并[3,4-c]噻吩的合成和化学性质研究进展.     

Facile and Convenient Synthesis of Pyrazole,Pyridine, Pyridazine,Pyrazolo[3,4-b]pyridine,and Pyrazolo[5,1-c][1,2,4]triazine Derivatives

Abstract

A convenient synthesis of a series of pyrazole, pyridine, pyridinethione, pyridazine, pyrazolo[3,4-b]pyridine, imidazo[1,2-a]pyrimidine, and pyrazolo[5,1-c][1 Kumar , R. 5-(1-Substituted)alkyl pyrimidine nucleosides as antiviral (herpes) agents . Curr. Med. Chem. 2004 , 11 , 2749 – 2766 . [Google Scholar] 2 Holy , A. ; Günter , J. ; Dvoráková , H. ; Masojídková , M. ; Andrei , G. ; Snoeck , R. ; Balzarini , J. ; De Clercq , E. Structure–antiviral activity relationship in the series of pyrimidine and purine N-[2-(2-phosphonomethoxy)ethyl] nucleotide analogues, 1: Derivatives substituted at the carbon atoms of the base . J. Med. Chem. 1999 , 42 , 2064 – 2086 . [Google Scholar] 4 Brandes , W. ; Daum , W. ; Krauss , P. Fungicidal oxime ethers. Ger. Patent 2,623,847, 1977; Chem. Abstr . 1978 , 88 , 120822h . [Google Scholar]]triazine derivatives incorporating a pyrimidine moiety, via the reactions of the versatile, readily accessible 3-oxo-N-(pyrimid-2-yl)butanamide with the appropriate reagents, is described.     

Synthesis of new pyrido[3,4-c]carbazole derivatives

Previously unknown 2-[6-hydroxy-9-(4-methoxyphenyl)-1,2,3,9-tetrahydro-4H-carbazol-4-ylidene]malononitrile was synthesized by the Nenitzescu reaction and was used for the construction of new tetracyclic compounds, viz., pyrido[3,4-c]carbazoles. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1600–1604, September, 2006.     

A facile synthesis of chromeno[3,4-c]spiropyrrolidine-oxindoles via 1,3-dipolar cycloadditions

A facile one-pot synthesis of chromene bearing novel spiropyrrolidine-oxindoles has been accomplished by the [3+‏2]-cycloaddition reaction of 3-acetyl-2H-chromen-2-ones with azomethine ylides derived in situ from isatin or N-methyl isatin with sarcosine.     

Tosylmethylisocyanide (TosMIC) [3+2] cycloaddition reactions: A facile Van Leusen protocol for the synthesis of the new class of spirooxazolines,spiropyrrolines and Chromeno[3,4-c]pyrrols

The reactivity and chemo-, regio- and diastreo-selectivity of tosylmethyl isocyanides (TosMIC) are investigated in Van Leusen type [3 + 2] cycloaddition reactions with the various activate cyclic ketones and double CC bonds in the synthesis of spirooxazolines, spiropyrrolines and chromeno[3,4-c]pyrrols in good to excellent yields under catalyst-free conditions without any activation at ambient temperature.     

Polyethylene glycol-promoted synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives in water

Synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives were achieved using polyethylene glycol (PEG-400) as promoting reaction medium in water under catalyst-free conditions at reflux and room temperature, respectively. The structure of pyrimido[1,2-a]benzimidazole was confirmed using ¹H NMR, ¹³C NMR, DEPT, and HMBC experiments. The promising points for the present methodology are efficiency, generality, high yield, short reaction time, cleaner reaction profile, ease of product isolation, simplicity, potential of recycling reaction medium, and finally agreement with green chemistry protocols.     

Synthesis of Several 2-Azafluorenones and 5H[1]Benzopyrano[3,4-c]Py Riding-Ones

Convenient syntheses of 2-azafluorenones 5a-f and 5H[1]benzopyrano[3,4-c]pyridin-5-ones 6a-b were performed by using intramolecular cyclization of 4-arylnicotinic acids 4a-F. 4a-f were obtained via permanganate oxidation from the corresponding of 4-arylpyridines 3a-f in good yields.     

Fe3O4@MCM-48-SO3H:An efficient magnetically separable nanocatalyst for the synthesis of benzo[f]chromeno[2,3-d]pyrimidinones

Sulfonic acid groups were grafted onto three different types of synthesized magnetic nanoparticles, namely Fe3O4, Fe3O4@SiO2, and Fe3O4@MCM‐48. The sulfonic acid‐functionalized nanoparticles were evalu...     

Fe3O4@MCM-48–SO3H:合成苯并[f]色烯并[2,3-d]嘧啶酮的高效、可磁性分离纳米催化剂（英文）

Sulfonic acid groups were grafted onto three different types of synthesized magnetic nanoparticles, namely Fe3O4, Fe3O4@SiO2, and Fe3O4@MCM‐48. The sulfonic acid‐functionalized nanoparticles were evaluated as catalysts for the synthesis of 5‐aryl‐1H‐benzo[f]chromeno[2,3‐d]pyrimidine‐2,4(3H,5H)‐dione derivatives in terms of activity and recyclability. Their catalytic activities were compared with that of the homogeneous acid catalyst 1‐methylimidazolium hydrogen sulfate ([HMIm][HSO4]). The activity of Fe3O4@MCM‐48–SO3H was comparable to those of the other heter‐ogeneous and homogeneous catalysts.     

3-氨基-6/8取代-1H-吡唑[4,3-c]喹啉类化合物的合成

研究了合成3-氨基-6/8取代-1H-吡唑[4,3-c]喹啉类化合物的简易方法.通过3-芳基-4-氨基-5-巯基-1,2,4-三唑与6-/8-取代-4-羟基喹啉羧酸在三氯氧磷催化下的缩合反应及所生成的3-芳基-6-(6-/8-取代-4-氯喹啉-3-基)-1,2,4-三唑[3,4-b]-1,3,4-噻二唑类化合物与水合肼在乙醇中的肼解反应,合成了6个3-氨基-6/8取代-1H-吡唑[4,3-c]喹啉类化合物,并对活泼的氨基进行了初步研究,新化合物通过元素分析,IR,¹HNMR和MS确定结构,并讨论了其波谱性质.     

Reactivity of the Mitsunobu reagent toward 3-formylchromones: a strategy for the one-pot synthesis of chromeno[2,3-c]pyrazolines and chromeno[2,3-e]tetrazepines

The zwitterionic intermediates generated from dialkyl azodicarboxylates and triphenylphosphine displayed excellent reactivity toward 3-formylchromones to afford chromeno[2,3-c]pyrazolines and chromeno[2,3-e]tetrazepines.     

Greener approach towards the facile synthesis of 1,4-dihydropyrano[2,3-c]pyrazol-5-yl cyanide derivatives at room temperature

This report describes triethylammonium acetate (TEAA) ionic liquid catalyzed one pot synthesis of 6-amino-4-aryl-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles by the reaction of aromatic aldehyde, malononitrile and 3-methyl-1-phenyl-2-pyrazolin-5-one at room temperature. TEAA plays dual role as reaction media and catalyst. It can also be easily recovered and reused in several runs. TEAA provides greener reaction protocol to present methodology which obviates the need of organic solvents, expensive and toxic catalyst.