Nitrogen bridgehead compounds. Part 80 unusual reaction of ethyl 9‐bromo‐4‐oxo‐6,7,8,9‐tetr ahydro‐4h‐pyrido[1,2‐a]pyrimidine‐3‐carboxylates and N‐Methylaniline

István Hermecz, Tibor Breining, Kálmán Simon, Tünde Erös‐Takácsy, Benjamin Podányi, John Sessi

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The acid‐catalysed intramolecular nucleophilic addition of the phenyl ring to the C(9a) = N(1) double bond of ethyl 9‐(N‐methyl‐N‐phenyl)‐4‐oxotetrahydro‐4H‐pyrido[1,2‐a]pyrimidine‐3‐carboxylates, formed in the reactions of ethyl 9‐bromo‐4‐oxo‐6,7,8,9‐tetrahydro‐4H‐pyrido[1,2‐a]pyrimidine‐3‐carboxylates and N‐methylaniline, gave the first examples of a new tetracyclic pyrimido[1′,2′:1,2]pyrido[3,2‐b]indole ring system (7). X‐ray diffraction analysis of 7a revealed that the annelation of the pyrimidine and piperidine rings is transoid, while that of the piperidine and pyrroline rings is cis, the piperidine ring adopts an unusual 6T8 twisted boat conformation, while the pyrroline ring has a 9T8a conformation.

Original languageEnglish
Pages (from-to)1405-1411
Number of pages7
JournalJournal of Heterocyclic Chemistry
Volume28
Issue number5
DOIs
Publication statusPublished - Jan 1 1991

ASJC Scopus subject areas

  • Organic Chemistry

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