title: Thermal oligomerisation of aryl isocyanides: formation of pyrazino[1,2-a:4,5-a']diindoles and indigo diarylimines.
abstract: The aryl isocyanides 1-4 are converted at 150 degrees C into the hexameric pyrazino[1,2-a:4,5-a']diindoles 15-19. 4-Fluorophenyl isocyanide, when heated at 135 degrees C, gave the hexamer 19 and the tetrameric indigo di-arylimine 9, and when kept at ambient temperature gave mainly the tetramer 9 in low yield. The structures of the hexamer 19 and the tetramer 9 were established by X-ray crystallography. Mechanisms are proposed for the oligomerisation reactions.
authors.affiliation: School of Chemistry, University of the Witwatersrand, Private Bag 3, WITS2050, Johannesburg, South Africa.
authors.forename: Jan C A
authors.initials: JC
authors.lastname: Boeyens
authors.forename: Leanne M
authors.initials: LM
authors.lastname: Cook
authors.forename: Yunxiang
authors.initials: Y
authors.lastname: Ding
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Fernandes
authors.forename: David H
authors.initials: DH
authors.lastname: Reid