Interconversions of Isatin‐Containing Condensed Tetracyclic Systems.

Abstract

Fused pyrrole derivatives R 0160Interconversions of Isatin-Containing Condensed Tetracyclic Systems. -Reaction of amino-substituted dibenzothiophenes (I) and (IX) with chloral hydrate and hydroxylamine followed by acid-catalyzed cyclization affords the corresponding benzothiophenoisatin derivatives (IV)/(V) and (XI)/(XII), resp., as regioisomeric mixtures. The interconversion of both regioisomers is achieved via a ring opening-acylation--cyclization sequence as demonstrated for derivatives (V) and (XII). -(KHOSHTARIA*, E. T.; KURKOVSKAYA, L. N.; BATSIKADZE, K. T.; MATNADZE, M. M.; SIKHARULIDZE, M. I.; DZHASHI, T. O.; ANANIASHVILI, V. O.; ABESADZE, I. G.; ALAPISHVILI, M. G.; Chem. Heterocycl.

Interconversions of isatin-containing condensed tetracyclic systems

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A new pathway has been proposed for the synthesis of dioxodihydro-1H-benzo [b]thiophenoindoles from the corresponding isomeric "amino acids" with amino groups at C (2) and C (3) . This method yields these tetracyclic systems not only as a single isomer but also permits their interconversion.

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A new pathway has been proposed for the synthesis of dioxodihydro-1H-benzo [b]thiophenoindoles from the corresponding isomeric "amino acids" with amino groups at C (2) and C (3) . The classical Sandmeyer reaction was used as a model for such conversions.Syntheses have been reported for benzo [b]thiopheno-1H-indoles, which are tetracyclic systems [1,2]. Linear isomers may be obtained from angular tetracyclic systems and, vice versa, the isomer with angular fusion of the pyrrole ring may be obtained from the linear isomer.

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“…Syntheses have been reported for benzo [b]thiopheno-1H-indoles, which are tetracyclic systems [1,2]. In light of the strong antibacterial activity of methisazone (β-thiosemicarbazone of N-methylisatin, Marboran), which belongs to the 1-methylisatin system containing a thiosemicarbazide fragment [3-6], we developed methods for the synthesis of tetracyclic condensed systems, containing "amino acid" elements as well as benzothiophene structures with linear and angular fusion of the pyrrole and benzene rings.…”