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Reaction of 3‐formylchromone‐ N ‐benzoylhydrazone with ketenes. Synthesis and structural studies of chromone 1,3,4‐oxadiazolines
Author(s) -
Kaspentakis George C.,
Tsoleridis Constantinos A.,
StephanidouStephanatou Julia
Publication year - 2007
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.5570440223
Subject(s) - chemistry , chromone , reaction mechanism , nuclear magnetic resonance spectroscopy , proton nmr , stereochemistry , medicinal chemistry , organic chemistry , catalysis
The reaction of 3‐formylchromone‐ N ‐benzoylhydrazone with ketenes, prepared in situ from the corresponding acid chlorides 2a‐d and the mixed anhydride 2e was studied. In all cases 2‐(4′‐oxo‐4′ H ‐3′‐chromyl)‐5‐phenyl‐2,3‐dihydro‐1,3,4‐oxadiazoles ( 3 ) were isolated in yields varying from 40 to 80%. A full structure assignment of all products has been made on the basis of 1D and 2‐D (COSY H‐H, COSY C‐H, COLOC C‐H) NMR spectra. A plausible reaction mechanism is also proposed based on theoretical approaches and experimental results.