Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives

Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives

The synthesis of new phenanthr[9,10-<i>e</i>][1,3]oxazines was achieved by the direct coupling of 9-phenanthrol with cyclic imines in the modified <i>aza</i>-Friedel–Crafts reaction followed by the ring closure of the resulting bifunctional aminophenanthrols with formaldehyde...

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Main Authors: Khadija Belasri, Leila Topal, Matthias Heydenreich, Andreas Koch, Erich Kleinpeter, Ferenc Fülöp, István Szatmári
Format: Article
Language:English
Published: MDPI AG 2020-05-01
Series:Molecules
Subjects:
modified Mannich reaction
cyclic imines
[4 + 2] cycloaddition
NMR spectroscopy
conformational analysis
DFT calculations
Online Access:https://www.mdpi.com/1420-3049/25/11/2524
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spelling doaj-2be646d684e94b2da5b8d74648c3909e2020-11-25T03:10:10ZengMDPI AGMolecules1420-30492020-05-01252524252410.3390/molecules25112524Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene DerivativesKhadija Belasri0Leila Topal1Matthias Heydenreich2Andreas Koch3Erich Kleinpeter4Ferenc Fülöp5István Szatmári6Institute of Pharmaceutical Chemistry and MTA-SZTE Stereochemistry Research Group, Hungarian Academy of Sciences, University of Szeged, Eötvös u. 6, H-6720 Szeged, HungaryInstitute of Pharmaceutical Chemistry and MTA-SZTE Stereochemistry Research Group, Hungarian Academy of Sciences, University of Szeged, Eötvös u. 6, H-6720 Szeged, HungaryDepartment of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam (Golm), GermanyDepartment of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam (Golm), GermanyDepartment of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam (Golm), GermanyInstitute of Pharmaceutical Chemistry and MTA-SZTE Stereochemistry Research Group, Hungarian Academy of Sciences, University of Szeged, Eötvös u. 6, H-6720 Szeged, HungaryInstitute of Pharmaceutical Chemistry and MTA-SZTE Stereochemistry Research Group, Hungarian Academy of Sciences, University of Szeged, Eötvös u. 6, H-6720 Szeged, HungaryThe synthesis of new phenanthr[9,10-<i>e</i>][1,3]oxazines was achieved by the direct coupling of 9-phenanthrol with cyclic imines in the modified <i>aza</i>-Friedel–Crafts reaction followed by the ring closure of the resulting bifunctional aminophenanthrols with formaldehyde. Aminophenanthrol-type Mannich bases were synthesised and transformed to phenanthr[9,10-<i>e</i>][1,3]oxazines via [4 + 2] cycloaddition. Detailed NMR structural analyses of the new polyheterocycles as well as conformational studies including Density Functional Theory (DFT) modelling were performed. The relative stability of <i>ortho</i>-quinone methides (<i>o</i>-QMs) was calculated, the geometries obtained were compared with the experimentally determined NMR structures, and thereby, the regioselectivity of the reactions has been assigned.https://www.mdpi.com/1420-3049/25/11/2524modified Mannich reactioncyclic imines[4 + 2] cycloadditionNMR spectroscopyconformational analysisDFT calculations
collection DOAJ
language English
format Article
sources DOAJ
author Khadija Belasri
Leila Topal
Matthias Heydenreich
Andreas Koch
Erich Kleinpeter
Ferenc Fülöp
István Szatmári
spellingShingle Khadija Belasri
Leila Topal
Matthias Heydenreich
Andreas Koch
Erich Kleinpeter
Ferenc Fülöp
István Szatmári
Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives
Molecules
modified Mannich reaction
cyclic imines
[4 + 2] cycloaddition
NMR spectroscopy
conformational analysis
DFT calculations
author_facet Khadija Belasri
Leila Topal
Matthias Heydenreich
Andreas Koch
Erich Kleinpeter
Ferenc Fülöp
István Szatmári
author_sort Khadija Belasri
title Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives
title_short Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives
title_full Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives
title_fullStr Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives
title_full_unstemmed Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives
title_sort synthesis and conformational analysis of naphthoxazine-fused phenanthrene derivatives
publisher MDPI AG
series Molecules
issn 1420-3049
publishDate 2020-05-01
description The synthesis of new phenanthr[9,10-<i>e</i>][1,3]oxazines was achieved by the direct coupling of 9-phenanthrol with cyclic imines in the modified <i>aza</i>-Friedel–Crafts reaction followed by the ring closure of the resulting bifunctional aminophenanthrols with formaldehyde. Aminophenanthrol-type Mannich bases were synthesised and transformed to phenanthr[9,10-<i>e</i>][1,3]oxazines via [4 + 2] cycloaddition. Detailed NMR structural analyses of the new polyheterocycles as well as conformational studies including Density Functional Theory (DFT) modelling were performed. The relative stability of <i>ortho</i>-quinone methides (<i>o</i>-QMs) was calculated, the geometries obtained were compared with the experimentally determined NMR structures, and thereby, the regioselectivity of the reactions has been assigned.
topic modified Mannich reaction
cyclic imines
[4 + 2] cycloaddition
NMR spectroscopy
conformational analysis
DFT calculations
url https://www.mdpi.com/1420-3049/25/11/2524
work_keys_str_mv AT khadijabelasri synthesisandconformationalanalysisofnaphthoxazinefusedphenanthrenederivatives
AT leilatopal synthesisandconformationalanalysisofnaphthoxazinefusedphenanthrenederivatives
AT matthiasheydenreich synthesisandconformationalanalysisofnaphthoxazinefusedphenanthrenederivatives
AT andreaskoch synthesisandconformationalanalysisofnaphthoxazinefusedphenanthrenederivatives
AT erichkleinpeter synthesisandconformationalanalysisofnaphthoxazinefusedphenanthrenederivatives
AT ferencfulop synthesisandconformationalanalysisofnaphthoxazinefusedphenanthrenederivatives
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