Syntheses and conformational analyses of new naphth[1,2-e][1,3]oxazino[3,2- c]quinazolin-13-ones

Renáta Csütörtöki, I. Szatmári, Andreas Koch, Matthias Heydenreich, Erich Kleinpeter, F. Fülöp

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The syntheses of naphth[1,2-e][1,3]oxazino[3,2-c]quinazolin-13-one derivatives (3a-f) were achieved by the solvent-free heating of benzyloxycarbonyl-protected intermediates (2a-f) with MeONa. For intermediates 2a-f, prepared by the reactions of substituted aminonaphthols with benzyl N-(2-formylphenyl)carbamate, not only the expected trans ring form B and chain form A 1, but also the rearranged chain form A 2 as a new tautomer were detected in DMSO at room temperature. The quantity of A 2 in the tautomeric mixture was changed with time. Conformational analyses of the target heterocycles 3a-f by NMR spectroscopy and accompanying theoretical calculations at the DFT level of theory revealed that the oxazine ring preferred a twisted chair conformation and the quinazolone ring was planar. Besides the conformations, both the configurations at C-7a and C-15 and the preferred rotamers of the 1-naphthyl substituent at C-15 were assigned, which allowed evaluation of the aryl substituent-dependent steric hindrance in this part of the molecules. Configurational assignments were corroborated by quantifying the ring current effect of 15-aryl in terms of spatial NICS.

Original languageEnglish
Pages (from-to)4600-4608
Number of pages9
JournalTetrahedron
Volume68
Issue number24
DOIs
Publication statusPublished - Jun 17 2012

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Conformations
Oxazines
Carbamates
Dimethyl Sulfoxide
varespladib methyl
Discrete Fourier transforms
Heating
Nuclear magnetic resonance spectroscopy
Magnetic Resonance Spectroscopy
Derivatives
Molecules
Temperature
C 15
altersolanol A

Keywords

  • Aminonaphthols
  • Conformational analysis
  • Naphthoxazinoquinazolinones
  • NMR spectroscopy
  • Ring current effect
  • Theoretical calculations

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Drug Discovery

Cite this

Syntheses and conformational analyses of new naphth[1,2-e][1,3]oxazino[3,2- c]quinazolin-13-ones. / Csütörtöki, Renáta; Szatmári, I.; Koch, Andreas; Heydenreich, Matthias; Kleinpeter, Erich; Fülöp, F.

In: Tetrahedron, Vol. 68, No. 24, 17.06.2012, p. 4600-4608.

Research output: Contribution to journalArticle

Csütörtöki, Renáta ; Szatmári, I. ; Koch, Andreas ; Heydenreich, Matthias ; Kleinpeter, Erich ; Fülöp, F. / Syntheses and conformational analyses of new naphth[1,2-e][1,3]oxazino[3,2- c]quinazolin-13-ones. In: Tetrahedron. 2012 ; Vol. 68, No. 24. pp. 4600-4608.
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