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Synthesis of pyrazole‐fused azepino[5,4,3‐ cd ]indoles
Author(s) -
Safieh Kayed A. Abu,
ElAbadelah Mustafa M.,
Zarga Musa H. Abu,
Sabri Salim S.,
Voelter Wolfgang,
MÖssmer Cäcilia M.
Publication year - 2001
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.5570380312
Subject(s) - chemistry , azepine , synthon , indole test , pyrazole , ring (chemistry) , acylation , combinatorial chemistry , stereochemistry , medicinal chemistry , organic chemistry , catalysis
Abstract The synthesis of some new pyrazolo[3′,4′:6,7]azepino[5,4,3‐ cd ] indoles (10a‐c) was achieved via regios‐elective cyclization of the respective 3‐(4‐acylaminopyrazol‐5‐yl)indoles (9a‐c) under Bischler‐Napieralski reaction conditions. The latter compounds were obtained by acylation of the corresponding 3‐(4‐aminopyra‐zol‐5‐yl)indoles (8a,b) which, in turn, were prepared by reduction of the 3‐(4‐nitropyrazol‐5‐yl)indoles precursors (7a,b) . The latter synthons were accessible from the reaction of indolylzinc chlorides (5a,b) with 5‐chloro‐1,3‐dimethyl‐4‐nitropyrazole. Ms and nmr spectral data of 10a‐c are in agreement with the assigned azepino‐indole structure as determined for 10a by X‐ray crystal measurements which demonstrate that the azepine ring is almost completely planar with the indole and pyrazole rings.