SUBSTITUENT EFFECTS ON THE TAUTOMER RATIOS BETWEEN THE HYDRAZONE IMINE AND DIAZENYL ENAMINE FORMS IN SIDE-CHAINED QUINOXALINES

Authors
KURASAWA Y HOSAKA T IKEDA K MATSUMOTO Y ISHIKURA A TAKADA A KIM HS OKAMOTO Y
Citation
Y. Kurasawa et al., SUBSTITUENT EFFECTS ON THE TAUTOMER RATIOS BETWEEN THE HYDRAZONE IMINE AND DIAZENYL ENAMINE FORMS IN SIDE-CHAINED QUINOXALINES, Journal of heterocyclic chemistry, 31(2), 1994, pp. 527-533
Citations number
14
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Journal of heterocyclic chemistry → ACNP
ISSN journal
0022152X
Volume
31
Issue
2
Year of publication
1994
Pages
527 - 533
Database
ISI
SICI code
0022-152X(1994)31:2<527:SEOTTR>2.0.ZU;2-A
Abstract
The arylhydrazono)methyl-2-oxo-1,2-dihydroquinoxalines 9-11 were synth esized by the reaction of the quinoxalines 6-8 with various p-substitu ted benzenediazonium salts. Compounds 9-11 showed the tautomeric equil ibria between the hydrazone imine A and diazenyl enamine B forms in di methyl sulfoxide media. The substituent effect on the tautomer ratios of A to B was studied by the nmr spectroscopy to clarify that the pres ence of the ester group R2 on the hydrazone carbon and electron-donati ng p-substituent R1 on the side chain benzene ring exhibited a tendenc y to increase the ratios of the tautomer A.