48916
2019
2019
eng
961
971
11
7
8
article
Wiley-VCH
Weinheim
1
2019-07-16
2019-07-16
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Ortho-Quinone methide driven synthesis of new O,N- or N,N-Heterocycles
To synthesize functionalized Mannich bases that can serve two different types of ortho-quinone methide (o-QM) intermediates, 2-naphthol and 6-hydroxyquinoline were reacted with salicylic aldehyde in the presence of morpholine. The Mannich bases that can form o-QM and aza-o-QM were also synthesized by mixing 2-naphthol, 2-nitrobenzaldehyde, and morpholine followed by reduction of the nitro group. The highly functionalized aminonaphthol derivatives were then tested in [4+2] cycloaddition with different cyclic imines. The reaction proved to be both regio- and diastereoselective. In all cases, only one reaction product was obtained. Detailed structural analyses of the new polyheterocycles as well as conformational studies including DFT modelling were performed. The relative stability of o-QMs/aza-o-QM were also calculated, and the regioselectivity of the reactions could be explained only when the cycloaddition started from aminodiol 4. It was summarized that starting from diaminonaphthol 25, the regioselectivity of the reaction is driven by the higher nucleophilicity of the amino group compared with the hydroxy group. 12H-benzo[a]xanthen-12-one (11), formed via o-QM formation, was isolated as a side product. The proton NMR spectrum of 11 proved to be very unique from NMR point of view. The reason for the extreme low-field position of proton H-1 could be accounted for by theoretical calculation of structure and spatial magnetic properties of the compound in combination of ring current effects of the aromatic moieties and steric compression within the heavily hindered H(1)-C(1)-C(12b)-C(12a)-C(12)=O structural fragment.
ChemistryOpen : including thesis treasury
10.1002/open.201900150
31341756
2191-1363
wos:2019
WOS:000477965100016
Szatmari, I; Fulop, F (reprint author), Univ Szeged, Inst Pharmaceut Chem, Eotvos U 6, H-6720 Szeged, Hungary.; Szatmari, I; Fulop, F (reprint author), Univ Szeged, MTA SZTE Stereochem Res Grp, Eotvos U 6, H-6720 Szeged, Hungary.; Szatmari, I; Fulop, F (reprint author), Univ Szeged, Interdisciplinary Excellence Ctr, Inst Pharmaceut Chem, Szeged, Hungary.; Kleinpeter, E (reprint author), Univ Potsdam, Dept Chem, Karl Liebknecht Str 4-25, D-14476 Golm, Germany., szatmari.istvan@pharm.u-szeged.hu; ekleinp@uni-potsdam.de; fulop@pharm.u-szeged.hu
Ministry of National Economy, National Research Development and Innovation Office [GINOP-2.3.2-15-2016-00038]; EUEuropean Union (EU) [EFOP-3.6.1-16-2016-00008]; Ministry of Human Capacities, Hungary Grant [20391-3/2018/FEKUSTRAT]
2021-01-14T12:12:52+00:00
sword
importub
filename=package.tar
85d20a0245facff2807fd37780c5e072
Szatmari, Istvan
Kleinpeter, Erich
Fülöp, Ference
false
true
CC-BY-NC-ND - Namensnennung, nicht kommerziell, keine Bearbeitungen 4.0 International
Istvan Szatmari
Khadija Belasri
Matthias Heydenreich
Andreas Koch
Erich Kleinpeter
Ferenc Fulop
eng
uncontrolled
ortho-quinone methide (o-QMs)
eng
uncontrolled
modified Mannich reaction
eng
uncontrolled
cycloaddition
eng
uncontrolled
NMR spectroscopy
eng
uncontrolled
conformational analysis
eng
uncontrolled
DFT calculations
Chemie und zugeordnete Wissenschaften
Institut für Chemie
Referiert
Import
Gold Open-Access
DOAJ gelistet
35821
2012
2012
eng
4600
4608
9
24
68
article
Elsevier
Oxford
1
--
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Syntheses and conformational analyses of new naphth[1,2-e][1,3]oxazino[3,2-c] quinazolin-13-ones
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.
Tetrahedron
10.1016/j.tet.2012.04.026
0040-4020
wos:2011-2013
WOS:000304798800005
Kleinpeter, E (reprint author), Univ Potsdam, Dept Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Golm, Germany., ekleinp@uni-potsdam.de; fulop@pharm.u-sze-ged.hu
Hungarian Research Foundation (OTKA) [K-75433]; Deutsche Akademische
Austauschdienst (DAAD) [50368559]; Bolyai Janos Fellowship;
[TAMOP-4.2.1/B-09/KONV-2010-0005]
Renata Csütörtöki
Istvan Szatmari
Andreas Koch
Matthias Heydenreich
Erich Kleinpeter
Ferenc Fulop
eng
uncontrolled
Naphthoxazinoquinazolinones
eng
uncontrolled
Aminonaphthols
eng
uncontrolled
NMR spectroscopy
eng
uncontrolled
Conformational analysis
eng
uncontrolled
Theoretical calculations
eng
uncontrolled
Ring current effect
Institut für Chemie
Referiert