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Reductive Cyclization (reductive + cyclization)
Selected AbstractsChemInform Abstract: Construction of Tetrahydrofuran-3-ones from Readily Available Organochalcogen Precursors via Radical Carbonylation/Reductive Cyclization.CHEMINFORM, Issue 21 2002Stefan Berlin Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] An Unprecedented Route for the Synthesis of 3,3,-Biindoles by Reductive Cyclization of 3-[2-Nitro-1-(2-nitrophenyl)ethyl]-1H -indoles Mediated by Iron/Acetic AcidEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2010Chintakunta Ramesh Abstract An unprecedented route for the synthesis of 3,3,-biindoles is developed. Both symmetrical and unsymmetrical 3,3,-biindoles could be generated by this method. Mild conditions, high yields of the products, and environmentally acceptable reagent are the merits of the procedure. [source] Straightforward Strategy for the Stereoselective Synthesis of Spiro-Fused (C-5)Isoxazolino- or (C-3)Pyrazolino-(C-3)quinolin-2-ones from Baylis,Hillman Adducts by 1,3-Dipolar Cycloaddition and Reductive Cyclization,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2008Virender Singh Abstract A straightforward and general approach for the stereoselective synthesis of spiro-fused (C-5)isoxazolino- or (C-3)pyrazolino-(C-3)quinolin-2-ones from the adducts offorded from the Baylis,Hillman reaction of 2-nitrobenzaldehyde and ethyl acrylate by sequential 1,3-dipolar cycloaddition and reductive cyclization is presented. It was found that the reductive cyclization of the isoxazoline derivatives proceeded efficiently in the presence of In/HCl, whereas similar reductions of pyrazolines gave better yields when carried out in the presence of an Fe/AcOH mixture. However, similar attempts employing the Baylis,Hillman adduct of 2-nitrobenzaldehyde and methyl vinyl ketone did not yield the desired compounds.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] ChemInform Abstract: Synthesis of Indolones and Quinolones by Reductive Cyclization of o-Nitroaryl Acids Using Zinc Dust and Ammonium Formate.CHEMINFORM, Issue 46 2008Bhima Reddy Dinesh Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Catalytic Enantioselective Reductive Cyclization of Acetylenic Aldehydes via Hydrogenation.CHEMINFORM, Issue 13 2008Jong Uk Rhee Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Convenient Synthesis of 1,2,4-Trisubstituted Azetidines by Reductive Cyclization of Aza-Michael Adducts of Chalcones.CHEMINFORM, Issue 8 2008Lal Dhar S. Yadav Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Highly Enantioselective Reductive Cyclization of Acetylenic Aldehydes via Rhodium Catalyzed Asymmetric Hydrogenation.CHEMINFORM, Issue 52 2006Jong Uk Rhee Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Intramolecular, Reductive Cyclization of ,-Ketoisothiocyanates Promoted by Using Samarium Diiodide.CHEMINFORM, Issue 12 2006Min Seok Cho Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Enantioselective Reductive Cyclization of 1,6-Enynes via Rhodium-Catalyzed Asymmetric Hydrogenation: C,C Bond Formation Precedes Hydrogen Activation.CHEMINFORM, Issue 38 2005Hye-Young Jang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Reductive Cyclization of N-(2,4-Dinitrophenyl)pyridinium Chloride by Tin(II) Chloride.CHEMINFORM, Issue 23 2005R. S. Begunov Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Versatile Method for the Synthesis of Benzimidazoles from o-Nitroanilines and Aldehydes in One Step via a Reductive Cyclization.CHEMINFORM, Issue 21 2005Donglai Yang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Stereoselective Synthesis of 3,4,5,6-Tetrasubstituted (1R,2R)-Diaminocyclohexanes by Zirconium-Promoted Reductive Cyclization.CHEMINFORM, Issue 41 2003Stefano Grilli Abstract For Abstract see ChemInform Abstract in Full Text. [source] Spiroannulation by Alkylation and Reductive Cyclization of Nitriles.CHEMINFORM, Issue 24 2003Scott D. Rychnovsky Abstract For Abstract see ChemInform Abstract in Full Text. [source] Intramolecular, Reductive Cyclization of ,-Ketoisothiocyanates Promoted by Using Samarium DiiodideCHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2005Min Seok Cho Abstract A novel samarium diiodide (SmI2) promoted intramolecular cyclization of ,-ketoisothiocyanate, derived from ,,,-unsaturated esters and ammonium thiocyanate led to ,-hydroxythiolactams and/or thiolactams in high yields. Treatment of ,-ketoisothiocyanate with two equivalents of SmI2 gave a mixture of ,-hydroxythiolactam and thiolactam. Four equivalents of SmI2 afforded only thiolactam in high yields. The intramolecular cyclization took place with high to complete stereoselectivity. A mechanism to explain this transformation is proposed. [source] Reductive-Cyclization-Mediated Synthesis of Fused Polycyclic Quinolines from Baylis,Hillman Adducts of Acrylonitrile: Scope and Limitations,,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2009Virender Singh Abstract The synthesis of a variety of polycyclic quinolines is described. The target molecules were obtained in two steps by an initial reductive cyclization followed by another intramolecular cyclization in the allylamines afforded from either the acetates or allyl bromides of Baylis,Hillman adducts of 2-nitrobenzaldehydes and acrylonitrile. The two steps proceeded in one-pot for those substrates in which a formyl or hydroxy group reacted with the amino group of the 2-aminoquinoline in the second intramolecular cyclization. In contrast, a basic medium was necessary for the second intramolecular cyclization reaction in substrates in which an alkoxycarbonyl group and the amino group participated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Straightforward Strategy for the Stereoselective Synthesis of Spiro-Fused (C-5)Isoxazolino- or (C-3)Pyrazolino-(C-3)quinolin-2-ones from Baylis,Hillman Adducts by 1,3-Dipolar Cycloaddition and Reductive Cyclization,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2008Virender Singh Abstract A straightforward and general approach for the stereoselective synthesis of spiro-fused (C-5)isoxazolino- or (C-3)pyrazolino-(C-3)quinolin-2-ones from the adducts offorded from the Baylis,Hillman reaction of 2-nitrobenzaldehyde and ethyl acrylate by sequential 1,3-dipolar cycloaddition and reductive cyclization is presented. It was found that the reductive cyclization of the isoxazoline derivatives proceeded efficiently in the presence of In/HCl, whereas similar reductions of pyrazolines gave better yields when carried out in the presence of an Fe/AcOH mixture. However, similar attempts employing the Baylis,Hillman adduct of 2-nitrobenzaldehyde and methyl vinyl ketone did not yield the desired compounds.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Two-step syntheses of 3-methyl and 3-phenyl-1,2,4-benzotriazinesHETEROATOM CHEMISTRY, Issue 2 2006Mohamed Khodja 3-Methyl-1,2,4-benzotriazine and some of its derivatives were prepared in moderate yields (50,70%) via a reductive cyclization by a PtO2 -catalyzed hydrogenation of the corresponding 2-nitrophenylhydrazones of the pyruvic acid. The latter compounds were obtained in yields higher than 90% by reacting 2-nitrophenylhydrazines with sodium pyruvate salt. Three 3-phenyl-1,2,4-benzotriazine compounds were also produced via a reductive cyclization by a Pt/C-catalyzed hydrogenation of their corresponding 2-nitrophenylhydrazono-ethers in high yields (>70%). © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:166,172, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20200 [source] One-pot synthesis of imidazo[1,2- c]quinazoline derivatives from nitro-componds reduced by zincJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2009Da-Qing Shi An efficient, convenient, one-pot synthesis of imidazo[1,2- c]quinazolines was accomplished in good yields via the novel reductive cyclization of 2-(2-nitrophenyl)-1H -imidazole with isothiocyanates mediated by zinc dust. J. Heterocyclic Chem., (2009). [source] ChemInform Abstract: Efficient One-Pot Synthesis of 6-Arylpyrrolo[3,2-d]pyrimidines from 6-Arylethynyl-5-nitropyrimidines.CHEMINFORM, Issue 36 2010Inga Cikotiene Abstract The synthesis of the biologically important heterocyclic system involves conjugative addition of diethylamine to ethynylpyrimidines (I) and subsequent reductive cyclization. [source] Low-valent titanium induced reductive cyclization of nitro compounds and aliphatic ketones: facile synthesis of 3, 4-dihydro(2H) - 1, 2, 4-benzothiadiazine-1, 1-dioxidesCHINESE JOURNAL OF CHEMISTRY, Issue 5 2000Wei-Hui Zhong Abstract The intermolecular reductive cyclization of o -nitrobenzene-sulfonamides with aliphatic ketones induced by TiCl4/Sm system was studied and a series of 3, 3-disubstituted-3,4-dihydro(2H)-1,2, 4-benzothiadiazine-1,1-dioxides were synthesized in moderate to high yields under mild and neutral conditions. [source] | ||||||||||||||||||||||