title: Indium/TFA-catalyzed synthesis of tetracyclic [6,5,5,6] indole ring, via a tandem cycloannulation of β-oxodithioester with tryptamine.
abstract: The cycloannulation of β-oxodithioesters and tryptamine in dichloromethane in the presence of a catalytic amount of InCl3 and TFA gave the novel 5-aryl/heteroaryl 2a(1),9b-dihydro-1H-2a,5a-diaza-cyclopenta[jk]fluorene-3(2H)-thiones in moderate to good yields. The reaction was proposed to involve a tandem transformation of thioamide, protonation, and dehydrative cyclization. KMnO4-oxidation of these newly prepared compounds yielded oxidative desulfurization products in good yields.
authors.affiliation: Department of Chemistry, Manipur University, Canchipur-795003, Manipur, India.
authors.forename: Thokchom Prasanta
authors.initials: TP
authors.lastname: Singh
authors.forename: Suman
authors.initials: S
authors.lastname: Bhattarcharya
authors.forename: Okram Mukherjee
authors.initials: OM
authors.lastname: Singh
mesh_terms: D002384:Catalysis; D003500:Cyclization; D004952:Esters; D006576:Heterocyclic Compounds, 4 or More Rings / Q000138:chemical synthesis* / Q000737:chemistry; D007204:Indium / Q000737:chemistry*; D007211:Indoles / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D014269:Trifluoroacetic Acid / Q000737:chemistry*; D014363:Tryptamines / Q000737:chemistry*
chemical_list: D004952:Esters; D006576:Heterocyclic Compounds, 4 or More Rings; D007211:Indoles; D014363:Tryptamines; D007204:Indium; C030820:tryptamine; D014269:Trifluoroacetic Acid