1226977-89-4Relevant academic research and scientific papers
AgI-catalyzed cascade strategy: Regioselective access to diversely substituted fused benzimidazo[2,1-a]isoquinolines, naphthyridines, thienopyridines, and quinoxalines in water
Rustagi, Vineeta,Tiwari, Rakesh,Verma, Akhilesh Kumar
, p. 4590 - 4602 (2012/11/07)
An environmentally benign and operationally simple one-pot approach to the regioselective tandem synthesis of diversely substituted fused benzimidazo[2,1-a]isoquinolines, naphthyridines, thienopyridines, and quinoxalines from o-alkynylaldehydes and arylamines with tethered nucleophiles using AgI as catalyst in water is described. The reaction showed selective N-C bond formation on the more electrophilic alkynyl carbon, resulting in the regioselective 6-endo-dig cyclized products in good to excellent yields. The proposed mechanistic pathway for the synthesis of fused heterocycles proceeding through formation of ring A prior to ring B, which formed through a second intramolecular attack of the nitrogen onto the alkynyl carbon, was supported by mechanistic experiments and X-ray crystallographic studies of isolated intermediate U and cyclized product 5a. Comparative experiments showed the viability of intramolecular nucleophilic attack over intermolecular attack of an external nucleophile. This catalytic, green protocol has been efficiently applied for the bis-tandem cyclization in water. An eco-friendly, one-pot cascade approach to benzimidazoles and quinoxalines in water using AgNO 3 as catalyst from o-alkynyl aldehydes and amines with tethered nucleophiles, has been developed. Selective 6-endo-dig regioselectivity and structural diversity are accomplished in good yields with a range of substrates. X-ray crystallographic studies and mechanistic experiments are also presented. Copyright
Facile assembly of fused isoquinolines by gold(i)-catalyzed coupling-cyclization reactions between o-alkynylbenzaldehydes and aromatic amines containing tethered nucleophiles
Patil, Nitin T.,Mutyala, Anil Kumar,Pediredla, G. V. V. Lakshmi,Penmatcha, V. K. Raju,Balasubramanian, Sridhar
supporting information; experimental part, p. 1999 - 2007 (2010/06/15)
A gold(I)-catalyzed, operationally simple coupling-cyclization technique was developed for the synthesis of isoquinoline-fused polycyclic compounds. The reaction makes use of two coupling partners such as o-alkynylbenzaldehydes and aromatic amines having tethered nucleophiles. The reaction is easy to perform, broad in scope, and allows the generation of a number of biologically important heterocyclic motifs from readily accessible starting materials. A mechanism for the reaction is discussed.
