A novel approach to the indoloquinoline alkaloids cryptotackieine and cryptosanguinolentine by application of cyclization of o-vinylsubstituted arylheterocumulenes

1-Methyl-3-(o-azidophenyl)quinoline-2-one prepared by cyclization of the corresponding o-vinylsubstituted isocyanate under microwave irradiation is directly converted into cryptotackieine 1 by an intramolecular aza-Wittig reaction with trimethylphosphine; alternatively heating followed by reduction of the resulting indoloquinoline derivative provided cryptosanguinolentine 2. (C) 2001 Elsevier Science Ltd. All rights reserved.