5,11-Dimethyl-6,12-dimethoxyindolo[3,2-b]carbazole

Abstract

Key indicators: single-crystal X-ray study; T = 193 K; mean (C-C) = 0.003 Å; R factor = 0.049; wR factor = 0.152; data-to-parameter ratio = 13.4.The title compound, C 22 H 20 N 2 O 2 , was prepared in a twofold Cadogan cyclization followed by double N-methylation. The crystal structure is characterized by a zigzag arrangement of centrosymmetric molecules. The indolocarbazole framework is essentially planar [maximum deviation = 0.028 (2) Å ] and the methoxy groups are orthogonal to this plane [C-C-O-C torsion angle = À88.2 (2) ]. The lengths of the C-N bonds are nearly identical and all C-C bonds of the pyrrole subunit are significantly longer than the C-C bonds in the benzene rings.

Chemistry and Properties of Indolocarbazoles

“…279 Similar strategy was used by the same group for preparation of the closely related 5,11-dihydro-6,12-dimethoxy-5,11dimethylindolo[3,2-b]carbazole, which was also subjected to a single-crystal X-ray study. 280 In this context, it is also worth mentioning that a single example of an indolo[3,2-b]carbazole has been reported as a minor product in low yield from a conceptually related palladium-catalyzed reductive cyclization of a nitroaromatic precursor in the presence of hydrogen. 281 An extensive set of extended indolo[3,2-b]carbazoles obtained using a sequence involving double Suzuki and Cadogan reactions has been reported.…”

“…The structure of the product 272 was corroborated by X-ray crystallography . Similar strategy was used by the same group for preparation of the closely related 5,11-dihydro-6,12-dimethoxy-5,11-dimethylindolo­[3,2- b ]­carbazole, which was also subjected to a single-crystal X-ray study . In this context, it is also worth mentioning that a single example of an indolo­[3,2- b ]­carbazole has been reported as a minor product in low yield from a conceptually related palladium-catalyzed reductive cyclization of a nitroaromatic precursor in the presence of hydrogen …”

Synthesis of Linearly Fused Benzodipyrrole Based Organic Materials

“…Wrobel et al exploited a microwave assisted Cadogan ring closure on terphenyl 55 to obtain 6,12-dialkoxy-indolo[3,2- b ]carbazole 56 in reasonable yield (Scheme 16) [43].…”

1,4,9,12-Tetramethoxy-14-octyl-5,8-dihydrodiindolo[3,2-b;2′,3′-h]carbazole with an unknown solvent

“…Among the different synthetic routes (Vlasselaer & Dehaen, 2016), the twofold Cadogan reaction (Cadogan et al, 1965) is a very successful route to indolocarbazoles (Kistenmacher & Mü llen, 1992;Wrobel et al, 2013) and is also suitable for the preparation of higher oligomers (Srour et al, 2016). In a continuation of our studies on indolo-annulated heterocycles (Dassonneville et al, 2011;Nissen & Detert, 2011;Letessier & Detert, 2013), we present here the first X-ray structure of a linear diindolocarbazole (Fig.…”