A new approach to construct a fused 2-ylidene chromene ring: Highly regioselective synthesis of novel chromeno quinoxalines

No Thumbnail Available
Shiva Kumar, K.
Rambabu, D.
Prasad, Bagineni
Mujahid, Mohammad
Krishna, G. Rama
Basaveswara Rao, M. V.
Malla Reddy, C.
Vanaja, G. R.
Kalle, Arunasree M.
Pal, Manojit
Journal Title
Journal ISSN
Volume Title
Regioselective construction of a fused 2-ylidene chromene ring was achieved for the first time by using AlCl 3-induced C-C bond formation followed by Pd/C-Cu mediate coupling-cyclization strategy. A number of chromeno[4,3-b]quinoxaline derivatives were prepared by using this strategy. Single crystal X-ray diffraction study of a representative compound e.g. 6-(2,2-dimethylpropylidene)-4-methyl-6H-chromeno[4,3-b]quinoxalin-3-ol confirmed the presence of an exocyclic C-C double bond with Z-geometry. The crystal structure analysis and hydrogen bonding patterns of the same compound along with its structure elaboration via propargylation followed by Sonogashira coupling of the resulting terminal alkyne is presented. A probable mechanism for the formation of 2-ylidene chromene ring is discussed. Some of the compounds synthesized showed anticancer properties when tested in vitro. © 2012 The Royal Society of Chemistry.
Organic and Biomolecular Chemistry. v.10(24)