208-71-9Relevant academic research and scientific papers
Thermal Ring Contraction of Dibenz[b,f]azepin-5-yl Radicals: New Routes to Pyrrolo[3,2,1-jk]carbazoles
Crawford, Lynne A.,McNab, Hamish,Mount, Andrew R.,Wharton, Stuart I.
, p. 6642 - 6646 (2008/12/22)
(Chemical Equation Presented) Flash vacuum pyrolysis (FVP) of N-allyl- or N-benzyldibenz[b,f]azepine at temperatures from 750 to 950°C gives pyrrolo[3,2,1-jk]carbazole as the major product. The mechanism of the ring contraction involves dibenzazepin-1-yl radical formation, followed by transannular attack and formation of a 2-(indol-1-yl)phenyl radical which cyclizes. The mechanism is supported by independent generation of 2-(indol-1-yl)phenyl radicals by two different methods, and the use of 1-(2-nitrophenyl)indole as a radical generator gives an optimized synthetic route to pyrrolo[3,2,1-jk]carbazole (54% overall yield in two steps from indole). The first substituted pyrrolo[3,2,1-jk]carbazoles have been synthesized by FVP methods and also by reactions of the parent compound with electrophiles, leading to a range of 4-substituted pyrrolocarbazoles.
