Collect. Czech. Chem. Commun. 2000, 65, 1163-1172

A New Approach to Imidazo[1,5-a]indole Derivatives

Peter Kutschya,*, Mojmír Suchýa, Milan Dzurillaa, Mitsuo Takasugib and Vladimír Kováčikc

a Department of Organic Chemistry, Faculty of Natural Sciences, P. J. Šafárik University, Moyzesova 11, 041 67 Košice, Slovak Republic
b Division of Material Sciences, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan
c Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 842 38 Bratislava, Slovak Republic


Reaction of indole-2-carbonyl isothiocyanate (1) with sodium methanethiolate afforded 1-thioxo-1H-imidazo[1,5-a]indol-3(2H)-one (3). Its methylation with methyl iodide in the presence of lithium hydride in dimethylformamide, or potassium carbonate in acetone resulted in the formation of corresponding S- and N-methyl derivatives 4 and 5. N-(Indole-2-carbonyl)thiocarbamates and N-(indole-2-carbonyl)thioureas prepared by treatment of isothiocyanate 1 with corresponding nucleophilic reagents were S-methylated with methyl iodide in acetone in the presence of potassium carbonate. The obtained N-(indole- 2-carbonyl) substituted thiocarbonimidates 15, 16 and isothioureas 17-20 afforded by treatment with lithium hydride in dimethylformamide the derivatives of imidazo[1,5-a]- indol-3-one 23-28 in 49-87% yields. Antifungal activity of the prepared compounds has been examined, using the fungus Bipolaris leersiae. 1-Methylsulfanyl-3H-imidazo-[1,5-a]- indol-3-one (4) exhibited the highest antifungal activity.

Keywords: Imidazoles; Indoles; Phytoalexins; Cyclization; Isothiocyanates; Antifungal activity.

References: 18 live references.