title: A new approach to construct a fused 2-ylidene chromene ring: highly regioselective synthesis of novel chromeno quinoxalines.
abstract: 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.
authors.affiliation: Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500046, India.
authors.forename: K Shiva
authors.initials: KS
authors.lastname: Kumar
authors.forename: D
authors.initials: D
authors.lastname: Rambabu
authors.forename: Bagineni
authors.initials: B
authors.lastname: Prasad
authors.forename: Mohammad
authors.initials: M
authors.lastname: Mujahid
authors.forename: G Rama
authors.initials: GR
authors.lastname: Krishna
authors.forename: M V Basaveswara
authors.initials: MV
authors.lastname: Rao
authors.forename: C Malla
authors.initials: CM
authors.lastname: Reddy
authors.forename: G R
authors.initials: GR
authors.lastname: Vanaja
authors.forename: Arunasree M
authors.initials: AM
authors.lastname: Kalle
authors.forename: Manojit
authors.initials: M
authors.lastname: Pal
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D003500:Cyclization; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011810:Quinoxalines / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D001578:Benzopyrans; D011810:Quinoxalines