Premium
Synthesis of 1,2‐dihydroindolo [1,7‐ AB ] [1,5] benzodiazepines and related structures . A new heterocyclic ring system
Author(s) -
Glamkowski Edward J.,
Fortunato James M.
Publication year - 1979
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570160508
Subject(s) - chemistry , indoline , ring (chemistry) , sodium borohydride , amide , dehydrogenation , benzodiazepine , yield (engineering) , diazepine , medicinal chemistry , stereochemistry , combinatorial chemistry , organic chemistry , catalysis , biochemistry , materials science , receptor , metallurgy
The synthesis of the novel 1,2‐dihydroindolo [1,7‐ ab ][1,5]benzodiazepine ring system 4 is described. Condensation of 2‐fluoronitrobenzene with indoline provided the starting material for the synthesis, 1‐(2‐nitrophenyl)indoline (1a) in high yield. The nitro group was reduced catalytically and the resulting amino function was acylated to afford the heterocycle percursor amide 3. Refluxing this amide in phosphorus oxychloride brought about a Bischler‐Napieralski type cyclodehydration to form the target 1,2‐dihydroindolo[1,7‐ ab ][1,5]benzodiazepine ring system. Dehydrogenation of the latter led to the fully aromatic indolo[1,7‐ ab ][1,5]benzodiazepine structure 5, while reduction with sodium borohydride provided the 1,2,6,7‐tetrahydroindolo[1,7‐ ab ]‐[1,5]benzodiazepine tetracycle 6.