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Reaction of α,β‐unsaturated carbodiimides with enamines leading to fused pyridine derivatives
Author(s) -
Noguchi Michihiko,
Onimura Kenjiro,
Isomura Yuji,
Kajigaeshi Shoji
Publication year - 1991
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.5570280409
Subject(s) - chemistry , pyridine , isocyanate , ring (chemistry) , amine gas treating , enamine , medicinal chemistry , organic chemistry , catalysis , polyurethane
The treatment of (5,5‐dimethyl‐3‐oxo‐1‐cyclohexenyl)iminotriphenylphosphorane ( 2 ) with phenyl isocyanate ( 3a ) gave N ‐(5,5‐dimethyl‐3‐oxo‐1‐cyclohexenyl)‐ N' ‐phenylcarbodiimide ( 4a ) in situ . The reaction of 4a with enamines proceeded smoothly to afford the pyridine ring formation with the elimination of amine. This means that 4a is regarded as a new class of 2‐aza‐1,3‐butadiene. The scopes and limitation of this reaction are also discussed.