Fused carbazoles by tandem aza Wittig/electrocyclic ring closure. Preparation of 6H-pyrido [4, 3-b] carbazole, 11H-pyrido [4, 3-a] carbazole and 11H-pyrido [3, 4-a] …
P Molina, PM Fresneda, P Almendros
文献索引：Molina, Pedro; Fresneda, Pilar M.; Almendros, Pedro Tetrahedron, 1993 , vol. 49, # 6 p. 1223 - 1236
Aza Wittig type reaction of iminophosphoranes 3, 12 and 16, prepared from the appropriate formylcarbazole by sequential treatment with ethyl azidoacetate and triphenylphosphine, with isocyanates leads to the linear 6H-pyrido [4, 3-b] carbazole 5, the angular 11H-pyrido [4, 3-a] carbazole 13 and the isomeric 11H-pyrido [3, 4-a] carbazole 19 respectively.
