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Synthesis and structure of pyrazolo[5,1‐ a ]isoindol‐8‐ones from Aromatic Ortho Diesters
Author(s) -
Chupp John P.,
Leo Gregory C.,
Molyneaux John M.
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.5570280314
Subject(s) - chemistry , ketone , condensation , ring (chemistry) , aromaticity , condensation reaction , medicinal chemistry , organic chemistry , stereochemistry , molecule , catalysis , physics , thermodynamics
The title compounds 2 , have now been shown to arise in certain cases from condensation of aromatic ortho ‐diesters with ketone, where formerly only indeno[1,2‐ c ]pyrazol‐4(1 H )‐ones 3 have been reported from such reaction. Heretofore 2 was obtained in a less direct fashion from phthalaldehydic acid esters. When hetero‐aromatic diesters were employed, new heterocyclic ring systems as represented by 2a,b ,c were prepared for the first time. Structures of 2 have been verified from detailed 1 H and 13 C nmr studies, while representative intermediates 4–9 in the condensation of diesters to 2 have been isolated and identified.