Nitrogen bridgehead compounds. Part 64. Protonation of 9- formyltetrahydropyrido [1,2-a]pyrimidin-4-ones and their analogues

Gabor Tóth, Aron Szöllosy, Csaba Szántay, Attila Almásy, István Hermecz, Ágnes Horváth, Lelle Vasvári-Debreczy, Zoltán Mészáros

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As shown by 1H, 13C, and 15N n.m.r. spectroscopy, protonation of 9-formyltetrahydropyrido[1,2-a]pyrimidin-4-ones takes place at the formyl oxygen atom. As a result, the enamine tautomer, predominant in the base form, is transformed into a protonated enolimine tautomer having an exocyclic double bond. 15N N.m.r. shifts reflect not only the state of the tautomeric equilibria but also the state of Z/E isomerism and the effect of remote substituents.

Original languageEnglish
Pages (from-to)1911-1916
Number of pages6
JournalJournal of the Chemical Society, Perkin Transactions 2
Issue number12
Publication statusPublished - Jan 1 1986


ASJC Scopus subject areas

  • Chemistry(all)

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