- Rapid access to novel 1,2,3-triazolo-heterocyclic scaffolds via tandem knoevenagel condensation/azide-alkyne 1,3-dipolar cycloaddition reaction in one pot
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An operationally simple, one-pot, two-step cascade method has been developed to afford biologically important fused 1,2,3-triazolo-heterocyclic scaffolds from 2-alkynyl aryl(heteroaryl) aldehydes and phenacyl azides. This unique atom economical transformation engages four reactive centers (aldehyde, alkyne, active methylene, and azide) under metal-free catalysis.
- Maurya, Ram Awatar,Adiyala, Praveen Reddy,Chandrasekhar,Reddy, Chada Narsimha,Kapure, Jeevak Sopanrao,Kamal, Ahmed
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p. 466 - 477
(2014/12/10)
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- Formation of condensed 1 H-pyrrol-2-ylphosphonates and 1,2-dihydropyridin- 2-ylphosphonates via Kabachnik-fields reaction of acetylenic aldehydes and subsequent 5-exo-dig or 6-endo-dig cyclizations
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Kabachnik-Fields reactions of various carbocyclic or heterocyclic acetylenic aldehydes together with subsequent Lewis acid catalyzed cyclizations have been studied. It was found that 5-exo-dig versus 6-endo-dig cyclization mode strongly depends on the structure of starting materials. Thus, nonaromatic acetylenic α-anilinomethylphosphonates underwent gold(III)-catalyzed or iodine-mediated 5-exo-dig cyclization to 1H-pyrrol-2-ylphosphonates. In contrast, electron-withdrawing heteroaromatic substrates formed 1,2-dihydropyridin-2-ylphosphonate ring containing materials via an exclusive 6-endo-dig ring-closure process. The dual mode of cyclization is possible only for α-amino (2-alkynylphenyl)methylphosphonates containing a benzene ring.
- Buk?naitienè, Rita,Urbanaitè, Aurelija,?ikotienè, Inga
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p. 6532 - 6553
(2014/08/05)
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- Rapid access to amino-substituted quinoline, (Di)benzofuran, and carbazole heterocycles through an aminobenzannulation reaction
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(Chemical Equation Presented) The use of a powerful aminobenzannulation reaction has been applied for the synthesis of amino-substituted quinolines, dibenzofurans, and carbazoles. The precursors are heterocycles bearing a methyl ketone group ortho to an i
- Tiano, Martin,Belmont, Philippe
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p. 4101 - 4109
(2008/09/20)
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- Synthesis of β- and γ-carbolines by the palladium/copper-catalyzed coupling and cyclization of terminal acetylenes
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A variety of 3-substituted β- and γ-carbolines have been synthesized from N-substituted 3-iodoindole-2-carboxaldehydes and 2-bromoindole-3-carboxaldehydes, respectively. The coupling of these aldehydes with various terminal acetylenes with PdCl2(PPh3)2/CuI as the catalyst readily affords the corresponding alkynylindole carboxaldehydes, which have subsequently been converted to the corresponding tert-butylimines and cyclized to β- and γ-carbolines by either copper-catalyzed or thermal processes.
- Zhang, Haiming,Larock, Richard C.
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p. 7048 - 7056
(2007/10/03)
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