Nitrogen bridgehead compounds. Part 70. Studies on quinolizine derivatives. Part 4. Ultraviolet‐visible spectra and chemical properties of some quinolizine derivatives and their monocyclic tautomers

Angéla Schwartz, László Szabó, Katalin Pusztay‐Szabó, I. Hermecz, Zoltán Mészáros

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2 Citations (Scopus)

Abstract

Ultraviolet‐visible spectra of 4‐oxo 1 and 4‐imino 2 quinolizines or their monocyclic tautomers 3, 4 have been studied in neutral, acidic and basic ethanolic solution as well as in dimethyl sulfoxide and chloroform. Ring B of 4‐oxo and 6‐unsubstituted 4‐imino compounds can be cleaved by sodium ethanolate more or less easily. Ring B of 6‐methyl‐4‐iminoquinolizines is very unstable and they are present mainly in the monocyclic form which are partly dissociated in ethanol and dimethyl sulfoxide especially in higher dilution or in the presence of sodium ethanolate. In dilute acidic ethanol or chloroform, the dissociation is suppressed and in the latter solvent and in some cases, absorption bands can be observed due to a small amount of the 4‐imino‐6‐methylquinolizines. In acidic solution of compounds 3B=C, 3D, 4E, 4F=G having simultaneously cyano and ethoxycarbonyl groups in 1 and 3 position, not simple reprotonation occurs but irreversible changes can be observed.

Original languageEnglish
Pages (from-to)655-660
Number of pages6
JournalJournal of Heterocyclic Chemistry
Volume24
Issue number3
DOIs
Publication statusPublished - 1987

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ASJC Scopus subject areas

  • Organic Chemistry

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