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  - 
TY  - JOUR
A1  - Balci, K.
A1  - Akkaya, Y.
A1  - Akyuz, S.
A1  - Collier, W. B.
A1  - Stricker, M. C.
A1  - Stover, D. D.
A1  - Ritzhaupt, G.
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - The effects of conformation and zwitterionic tautomerism on the structural and vibrational spectral data of anserine
JF  - Vibrational spectroscopy : an international journal devoted to applications of infrared and raman spectroscopy
N2  - In this study, the stable conformers of neutral anserine were searched by molecular dynamics simulations and energy minimization calculations using the MM2 force field. Thermochemical calculations at B3LYP/6-31G(d) level of theory followed these preliminary calculations. The results confirmed that neutral anserine has quite a flexible structure and many stable gauche and trans conformers at room temperature. Nevertheless, two are considerably more favourable in energy than the others and expected to dominate the gas-phase and matrix IR spectra of the molecule. The corresponding structural and vibrational spectral data for these two conformers of neutral anserine, whose relative stabilities were also examined by high-accuracy energy calculations carried out using G3MP2B3 method, and for the most stable conformer of anserine in zwitterion form were calculated at B3LYP/6-311++G(d,p) level of theory. The calculated harmonic force constants were refined using the Scaled Quantum Mechanical Force Field (SQM-FF) method and then used to produce the refined wavenumbers, potential energy distributions (PEDs) and IR and Raman intensities. These refined data together with the scaled harmonic wavenumbers obtained using another method, Dual Scale factors (DS), enabled us to correctly analyse the observed IR and Raman spectra of anserine and revealed the effects of conformation and zwitterionic tautomerism on its structural and vibrational spectral data. (C) 2016 Elsevier B.V. All rights reserved.
KW  - Anserine
KW  - Matrix IR spectrum
KW  - Tautomerism
KW  - SQM-FF
KW  - Dual scale factors
Y1  - 2016
U6  - https://doi.org/10.1016/j.vibspec.2016.08.003
SN  - 0924-2031
SN  - 1873-3697
VL  - 86
SP  - 277
EP  - 289
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - Y-aromaticity - existing: yes or no? An answer given on the magnetic criterion (TSNMRS)
JF  - Tetrahedron
N2  - The spatial magnetic properties (Through Space NMR Shieldings - TSNMRS) of a number of Y-shaped structures possessing 4n+2 pi-electrons (i.a. the trimethylenemethane ions TMM2+, TMM2-, the guanidinium cation, substituted and hetero analogues) have been computed, visualized as Isochemical Shielding Surfaces (ICSS) of various size and direction, were examined subject to present Y-aromaticity and the results compared with energetic and geometric criteria obtained already. (C) 2016 Elsevier Ltd. All rights reserved.
KW  - Y-aromaticity
KW  - pi-Electron delocalization
KW  - Theoretical calculations
KW  - ICSS
KW  - TSNMRS
Y1  - 2016
U6  - https://doi.org/10.1016/j.tet.2016.02.020
SN  - 0040-4020
VL  - 72
SP  - 1675
EP  - 1685
PB  - Elsevier
CY  - Oxford
ER  -