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Studies on quinones. Part 23 . Synthesis of azepinones fused to quinone systems
Author(s) -
Valderrama J. A.,
PessoaMahana H.,
Tapia R.
Publication year - 1992
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.5570290522
Subject(s) - chemistry , quinone , methacrolein , cycloaddition , cyclopentadiene , acetal , stereochemistry , benzazepine , bicyclic molecule , medicinal chemistry , organic chemistry , catalysis , polymer , monomer , methacrylic acid
The Diels‐Alder reactions of 3,4‐dihydro‐5 H ‐1‐benzazepine‐2,6,9‐trione 1 with butadiene, cyclopentadiene, 1‐( E )‐trimethylsiloxybutadiene 4 , and methacrolein dimethylhydrazone are described. Cycloaddition with the unsymmetrical dienes 4 and 18 occurs regiospecifically affording 5 and 19 respectively. The structure of 5 was established through naphthazepine 13 by comparison of its 1 H nmr with model compounds. The probable course of cycloaddition with 1‐azadiene 18 is analyzed considering the polarization of azadiene 18 and the behavior of quinone 1 in the reaction with 4 . Michael addition of quinone 1 with isobutenylmorpholine 23 which afforded exclusively the cyclic O,N‐acetal 24 or 25 and its convertion to benzepinquinone 26 or 27 is also reported.