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Friedel–Crafts Chemistry. Part 53. Divergent and
Diversity-Oriented Synthesis of Condensed Indole
Scaffolds via Friedel–Crafts Ring Closure Approach

Research Abstract
A series of indole-fused medium-sized N-heterocyclic systems 10a–h were prepared from laboratory-synthesized indole-based esters 9a–h via intramolecular Friedel–Crafts cyclizations induced by both trifluoromethanesulfonic acid and AlCl3/CH3NO2 catalysts under suitable conditions. The synthetic sequence to precursors 9a–h that started from simple N-methylindole-2-carboxylic acid involved conversion to aminoindoles 2a, b, reaction with a,b-unsaturated acid chlorides to yield acyclic amides 5a–d, ring closure to tricyclic lactams 6a–d, and carbonyl reduction to respective pyrido and azepino tricyclic amines 7a–d, which finally underwent N-alkylations with a- or b-haloesters to produce the required ester precursors. The structures of synthesized compounds without stereochemical implications are established using both spectral and analytical data.
Research Authors
Hassan A. K. Abd El-Aal and Ali A. Khalaf
Research Department
Research Journal
Journal compilation
Research Pages
pp. 276 - 287
Research Publisher
NULL
Research Rank
1
Research Vol
Vol. 72
Research Website
NULL
Research Year
2019