Premium
A novel approach to synthesis of the cinnoline ring system via organoiron(cyclopentadienyl) complexes
Author(s) -
Sutherland Ronald G.,
AbdElAziz Alaa S.,
Piórko Adam,
Gill Udai S.,
Lee Choi Chuck
Publication year - 1988
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.5570250412
Subject(s) - chemistry , hexafluorophosphate , cinnoline , ketone , cyclopentadienyl complex , alkyl , ring (chemistry) , amide , medicinal chemistry , aromatization , sodium methoxide , benzene , hydrazine (antidepressant) , stereochemistry , organic chemistry , catalysis , ionic liquid , chromatography
An efficient synthesis of 3‐mono or 3,4‐disubstituted cinnolines from ( o ‐dichlorobenzene)(cyclopentadienyl)iron hexafluorophosphate in three or four steps has been achieved. o ‐Chlorophenyl‐alkyl or alkylaryl ketone complexes obtained from the o ‐dichlorobenzene complex upon treatment with enolate anions, react with hydrazine forming 3‐mono or 3,4‐disubstituted 1,4‐dihydrocinnoline complexes. Treatment of the later with sodium amide leads to an aromatization‐demetallation reaction resulting in formation of cinnolines, i.e. 3‐methyl‐, 3‐phenyl‐ and 3,4‐dimethylcinnoline. The influence of substituents bonded to the carbon atom adjacent to the complexed benzene ring in o ‐chlorophenyl ‐alkyl or ‐alkylaryl ketone prior to cyclization on the cyclization reaction is discussed.