TY  - JOUR
A1  - Csütörtöki, Renata
A1  - Szatmari, Istvan
A1  - Koch, Andreas
A1  - Heydenreich, Matthias
A1  - Kleinpeter, Erich
A1  - Fulop, Ferenc
T1  - Syntheses and conformational analyses of new naphth[1,2-e][1,3]oxazino[3,2-c] quinazolin-13-ones
JF  - Tetrahedron
N2  - 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.
KW  - Naphthoxazinoquinazolinones
KW  - Aminonaphthols
KW  - NMR spectroscopy
KW  - Conformational analysis
KW  - Theoretical calculations
KW  - Ring current effect
Y1  - 2012
U6  - https://doi.org/10.1016/j.tet.2012.04.026
SN  - 0040-4020
VL  - 68
IS  - 24
SP  - 4600
EP  - 4608
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Barta, Petra
A1  - Szatmari, Istvan
A1  - Fueloep, Ferenc
A1  - Heydenreich, Matthias
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - Synthesis and stereochemistry of new naphth[1,3]oxazino[3,2-a] benzazepine and naphth[1,3]oxazino[3,2-e]thienopyridine derivatives
JF  - Tetrahedron
N2  - Through the reactions of 1- or 2-naphthol and 4,5-dihydro-3H-benz[c]azepine or 6,7-dihydrothieno[3,2-c]pyridine, new aminonaphthol derivatives were prepared. The syntheses were extended by using N-containing naphthol analogues such as 5-hydroxyisoquinoline and 6-hydroxyquinoline. The ring closures of the novel bifunctional compounds were also achieved, resulting in new naphth[2,1-e][1,3]oxazines, naphth[1,2-e][1,3]oxazines, isoquinolino[5,6-e][1,3]oxazines and quinolino[5,6-e][1,3]oxazines. H-1 NMR spectra of the target heterocycles 16, 20 and 21 were sufficiently resolved to indentify the present stereochemistry; therefore, beside computed structures, spatial experimental (dipolar coupling-NOE) and computed (ring current effect of the naphthyl moiety-TSNMRS) NMR studies were employed. The studied heterocycles exist exclusively as S(14b),R(N), R(14b),S(N), and S(16b)S(N) isomers, respectively. The flexible moieties of the studied compounds prefer. (C) 2016 Elsevier Ltd. All rights reserved.
KW  - Modified Mannich reaction
KW  - Thienopyridine
KW  - Benzazepine
KW  - NMR spectroscopy
KW  - Stereochemistry
KW  - Theoretical calculations
Y1  - 2016
U6  - https://doi.org/10.1016/j.tet.2016.03.058
SN  - 0040-4020
VL  - 72
SP  - 2402
EP  - 2410
PB  - Elsevier
CY  - Oxford
ER  -