Pyrrolo carbazole, synthesis

Indolo[3,2-fl]pyrrolo[3,4-c]carbazoles 120 have been obtained in one step from indole and the corresponding maleimides in acetic acid, with coformation of the Michael adducts 121 (Scheme 15). This reactitai required careful temperature control in order to obtain the desired product ratios. An alternative independent synthesis of compounds 120 could also be accompKshed from 2,3 -biindolyl (115) andsuitable maleimides in hot acetic acid (99T2363). The system 120 where R = H has also been reported as a minor product during studies toward a synthesis of the alkaloid arcyriaflavin A (95TL2689). 

Benchekroun-Mounir, N., Dugat, D., Gramain, J.C., and Husson, H.P. (1993) Stereocontrolled formation of octahydro-lH-pyrrolo[2,3-d]carbazoles by reductive cydization total synthesis of ( )-N-benzylaspidospermidine. Journal of Organic Chemistry, 58, 6457-6465. 

Witulski B, Schweikert T (2005) Synthesis of indolo[2,3-a]pyrrolo[3,4-c]carbazoles by oxidative cyclization of bisindolylmaleimides with a rhodium(Ill)-copper(II) catalytic system. Synthesis 1959-1966... 

The pyrrolo[3,4-Z ]indoles offer an alternative approach to access indolo-2,3-quinodimethane analogs and have also been used in Diels-Alder cycloaddition reactions with acetylenes to produce a variety of substituted carbazoles. The most widely used methods developed for the synthesis of pyrrolo[3,4-b]indoles have already been reviewed [126, 127] and thus wiU not be discussed here. 

Desarbre E, Bergman J (1998) Synthesis of symmetric and non-symmetric indolo[2,3-c] carbazole derivatives preparation of indolo[2,3-c]pyrrolo[3,4-a]carbazoles. J Chem Soc, Perkin Trans 1 2009-2016... 

Bleile M, Wagner T et al (2005) Synthesis of substituted pyrrolo[3, 4-a]carbazoles. Helv Chim Acta 88 2879-2891... 

Joseph B, Facompre M et al (2001) Synthesis, cytotoxicity, DNA interaction and topoisomer-ase II inhibition properties of tetrahydropyrrolo[3,4-a]carbazole-l, 3-dione and tetrahydropyr-ido-[3, 2-b]pyrrolo[3, 4-g]indole-l, 3-dione derivatives. Bioorg Med Chem 9 1533-1541... 

Synthesis of cycloruthenated pyrido[2,3-fl]pyrrolo[3,4-c]carbazole-5,7(6H)-diones and ruthenium complexes as protein kinase inhibitors 07SU177. 

The synthesis of dictyodendrins A and F was realized through a sequential C—H functionahzation strategy inclusive of an initial C3 arylation, a site-selective double C—H alkylation with an aryldiazoacetate derivative and a subsequent Suzuki-Miyaura cross-coupHng with indole-3-boronic acid pinacol ester 107 (2015JAC644). A formal 67r-electrocyc-lization of the resultant tetrasubstituted pyrrole 108 fashioned the required pyrrolo-[2,3-c]carbazole core (109) which was further elaborated to the targets. 

The intramolecular amine-halogen copper-promoted indohzation was applied to the synthesis of more-complex indoles (Scheme , equations 1 ) [58-61]. Other examples in this category of copper-catalyzed amination are syntheses of the carbazole alkaloids murrayaquinone-A and ( )-bis-murrayaquinone-A [62], 3-aryl p-carbolin-l-ones [63, 64], carbazoles from donble C-N cyclization [65], pyrrolo[2,3-c]... 

Sanz, Amaiz, and colleagues discovered that a dichlorodioxomolybdenum(VI) complex can reductively cyclize nitrobiphenyls to carbazoles and nitrostyrenes to indoles (Scheme 3, equations 1 and 2) [ 12]. The Mo-catalyzed cyclization was applied to the synthesis of 2-carbonyl indoles in one pot from o-nitrobenzaldehydes (equation 3) [12]. Waldvogel and colleagues used MoCl,/ TiCl to synthesize carbazoles via an oxidative cyclization of diaryl amines (equation 4) [13]. These conditions were superior to TiCl, FeClj, and Pd(OAc)j/HOAc. A Pauson-Khand reaction using Co(CO) was employed by Saito s team to prepare lff-pyrrolo[2,3-(>]indol-2-ones (equation 5) [8]. 

The synthesis and structure-activity relationships of 4-substituted cyclopent[a]pyrrolo[3,4-c]carbazole-5,7-dione analogs as potent poly (ADP-ribose) polymerase 1 (PARP-1) inhibitors. 

Hirao, S., Sugiyama, Y, Iwao, M., and Ishibashi, F. (2009) Synthetic approach to telomerase inhibitor dictyodendrin B Synthesis of the pyrrolo[2,3-c]carbazole core. Biosti. Biotechnol. Biochem., 73,1764-1772. 

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