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.

A new method for the synthesis of the dioxodihydro-1H-benzo [b]furoindole heterocyclic systems from the corresponding isomeric amino acids with the amino groups at positions 2 and 3 is described. By this method it is possible not only to obtain the indicated tetracyclic systems in the form of one isomer but also to interconvert them; from the tetracyclic systems with angular structure it is possible to obtain the corresponding isomers with linear structure and vice versa. The classical Sandmeyer reaction served a model for such transformations.

2005Benzopyran derivatives R 0350 7-Oxo-3,7-dihydro-and 1,2,7-Trioxo-1,2,3,7-tetrahydropyrano[3,2-e]indoles. -A coumarin-based synthesis of tricyclic condensed systems with an indole moiety in the molecule like in (III) and (V) is reported for the first time. -(KHOSHTARIYA, T. E.; BOCHOIDZE, L. T.; BATSIKADZE, K. T.; Chem. Heterocycl.

A preparative route is proposed for the synthesis of the novel heterocyclic systems 7-oxo-and 1,2,7-trioxo-1,2-dihydropyrano[3,2-e]indole using classical Fischer and Sandmeyer methods respectively. We have studied various conditions for cyclization of the starting coumarin 6-isonitrosoacetamide and the methyl or ethyl pyruvate 6-coumarinylhydrazones. The syn-and antiform ratio of the latter and the structure of all of the synthesized compounds were determined using spectroscopic data analysis.Keywords: 6-(isonitrosoacetamido)coumarin, 7-oxo-1,2-dihydropyrano[3,2-e]indole, Sandmeyer reaction, Fischer reaction, syn-Z-and anti-E-forms of pyruvate ester 6-coumarinylhydrazones, 1,2,7-trioxo-1,2-dihydropyrano[3,2-e]indole, cyclization.In continuing our study of condensed compounds containing a pyrrole ring [1-4] it was of interest to synthesize tricyclic systems which included indole and coumarin fragments. The interest in such a system is a result of the variety of the nature of the physiological activity of indole derivatives [5][6][7][8][9][10][11][12] and also the possibility of their use in the synthesis of alkaloids and alkaloid related substances.We have used classical Sandmeyer and Fischer reactions for the "addition" of a pyrrole ring to the bicyclic coumarin system (see Scheme).In the first case, the starting 6-aminocoumarin (1) was converted to the "isatin" 3 via the isonitrosoacetamide 2. In the second, the hydrazine hydrochloride 4 was obtained from the same amine via a diazonium salt and was then reacted with methyl or ethyl pyruvate to give the corresponding hydrazones 5a,b. Cyclization of the latter gave the target compounds 6a,b. _______ * Dedicated to the memory of a dear teacher, the prominent Russian science professor Nikolai Nikolaevich Suvorov. Founder of indole chemistry in Georgia. In love with, and a warm favourite of, Georgia. __________________________________________________________________________________________

Fused pyrrole derivatives R 0160 Condensed Tetracyclic Systems with an Isatin Fragment in the Molecule. -A similar reaction sequence is applied to 3-aminodibenzofuran. Condensed tetracyclic systems, e.g. (IV) and (V), are obtained from the ring closure of oximes. Angular structures, e.g. (IV), are easily transformed to the linear analogues and vice versa via intermediary amino acids. -(KHOSHTARIYA*, T. E.; KURKOVSKAYA, L. N.; MATNADZE, M. M.; SIKHARULIDZE, M. I.; DZHASHI, T. O.; ANANIASHVILI, V. O.; BATSIKADZE, K. T.; Chem. Heterocycl.