title: Regiospecific synthesis of mono-N-substituted indolopyrrolocarbazoles.
abstract: [reactions: see text] Two complementary and efficient strategies have been developed for the regiospecific synthesis of unsymmetrical indolopyrrolocarbazoles (IPCs) mono-N-substituted with a pentacycle. A halogen in position 2 of the intermediate bisindolylmaleimides 3a-e allows a selective Mitsunobu coupling by exploiting the increased acidity of the 2-chloro-substituted indole nitrogen. It also promotes an easier cyclization of bisindolylmaleimides 4a-e and 7b-e to IPCs. Alkylation of the 2-unsubstituted indole-3-carboxamides 2a,b and further processing to the corresponding IPCs gives access to the opposite regioisomers.
authors.affiliation: Chemistry Department, Sirenade Pharmaceuticals AG, Am Klopferspitz 19a, D-82152 Martinsried, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Fröhner
authors.forename: Barbara
authors.initials: B
authors.lastname: Monse
authors.forename: Tobias M
authors.initials: TM
authors.lastname: Braxmeier
authors.forename: Laura
authors.initials: L
authors.lastname: Casiraghi
authors.forename: Heidi
authors.initials: H
authors.lastname: Sahagún
authors.forename: Pierfausto
authors.initials: P
authors.lastname: Seneci
mesh_terms: D000478:Alkylation; D002227:Carbazoles / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D006027:Glycosides / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D002227:Carbazoles; D006027:Glycosides