Beilstein J. Org. Chem.2021,17, 2425–2432, doi:10.3762/bjoc.17.159
reaction and sequential aromatization process.
Keywords: carbazole; chalcone; Diels–Alder reaction; maleimide; pyrrolo[3,4-c]carbazole; 3-vinylindole; Introduction
Carbazole is one of the most well-known privileged nitrogen-containing heterocycles. The carbazole skeleton is widely occurring in natural
crystal structure of compound 4g was determined by X-ray diffraction (Figure 4). It can be seen that the ring of pyrrolo[3,4-c]carbazole exists in a slightly twisted plane. The dihedral angles of the phenyl and the benzoyl group to the central benzene ring are 72.018° and 88.402°.
To further expand the
petroleum ether and ethyl acetate 8:1 (v/v) as eluent to give the pure products for analysis.
5-Benzoyl-2-phenyl-4-(p-tolyl)pyrrolo[3,4-c]carbazole-1,3(2H,6H)-dione (4a): green solid, 440 mg, 87%; mp 234–236 °C; 1H NMR (400 MHz, CDCl3) δ 9.24 (s, 1H, ArH), 9.15 (d, J = 8.0 Hz, 1H, ArH), 7.60–7.56 (m, 1H
Beilstein J. Org. Chem.2018,14, 1619–1636, doi:10.3762/bjoc.14.138
].
In spite of the fact that parent indole is too weak an acid to undergo Mitsunobu conversions, a model maleimide–indole hybrid was investigated by Ohkubo and colleagues to pave the way for the synthesis of indolo[2,3-a]pyrrolo[3,4-c]carbazole compounds with anticancer activity [90][91]. N-Glycosides
PDF
Graphical Abstract
Scheme 1:
Left: The Mitsunobu reaction is essentially a nucleophilic substitution of alcohols occurring with ...