Studies on naphthyridines. An unexpected product in Hantzsch pyridine synthesis

Mária Balogh, I. Hermecz, G. Náray-Szabó, Kálmán Simon, Zoltán Mészáros

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Besides the expected pyridinedicarboxylate (4), triethyl 2,7,8a-trimethyl-1,4,4a,5,8,8a-hexahydro-1,8-naphthyridine-3,4a, 6-tricarboxylate (6) was also isolated in the Hantzsch pyridine synthesis starting from ethyl acetoacetate and hexamethylenetetramine in acetic acid. The 1,8-naphthyridine (6) was probably formed in the [4 + 2]cycloaddition of heterodiene (5) and the 1,4-dihydropyridinedicarboxylate (3). The observed regioselectivity was explained in terms of simple Hückel molecular orbital calculations. Diethyl 2,6-dimethylpyridine-3,5-dicarboxylate (4) gave ethyl 2-methyl-5-oxo-5,6-dihydro-1,6-naphthyridine-3-carboxylate (9) in high yield in a one-step reaction with 1,3,5-triazine in the presence of ethanolic sodium ethoxide, or in a two-step procedure with DMF diethyl acetal followed by ring closure with ammonia.

Original languageEnglish
Pages (from-to)753-757
Number of pages5
JournalJournal of the Chemical Society, Perkin Transactions 1
Publication statusPublished - 1986

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Naphthyridines
Methenamine
Orbital calculations
Regioselectivity
Acetals
Triazines
Cycloaddition
Molecular orbitals
Ammonia
Acetic Acid
pyridine

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Studies on naphthyridines. An unexpected product in Hantzsch pyridine synthesis. / Balogh, Mária; Hermecz, I.; Náray-Szabó, G.; Simon, Kálmán; Mészáros, Zoltán.

In: Journal of the Chemical Society, Perkin Transactions 1, 1986, p. 753-757.

Research output: Contribution to journalArticle

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AU - Mészáros, Zoltán

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