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  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Klod, Sabrina
A1  - Koch, Andreas
T1  - Visualization of through space NMR shieldings of aromatic and anti-aromatic molecules and a simple means to compare and estimate aromaticity
N2  - Through space NMR shieldings of aromatic (benzene, mono-substituted and annelated benzenes, ferrocene, [14]- and [18]-annulenes, phenylenes and tetra- to heptahelicene) and anti-aromatic molecules (cyclobutadiene and pentalene) were assessed by ab initio molecular-orbital calculations. Employing the nucleus-independent chemical shifts (NICS) concept, these through space NMR shieldings were visualized as iso-chemical-shielding surfaces (ICSSs) and can be applied quantitatively to determine the stereochemistry of proximal nuclei. In addition, the distances in Å at ICSS values of ±0.1 ppm in-plane and perpendicular-to-center of the aromatic ring system were employed as a simple means to compare and estimate qualitatively the aromaticity of the systems at hand.
Y1  - 2007
UR  - http://www.sciencedirect.com/science/journal/01661280
U6  - https://doi.org/10.1016/j.theochem.2007.02.049
SN  - 0166-1280
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - Visualization of homoaromaticity in cations, neutral molecules and anions by spatial magnetic properties (through space NMR shieldings) - an 1H/13C NMR chemical shift study
N2  - Prototypes for homoaromaticity in cations, neutral molecules, and anions are theoretically studied at the MP2 level of theory. For the global minimum structures on the potential energy surface both 1H/13C chemical shifts and spatial magnetic properties as through space NMR shieldings (TSNMRS) were calculated by the GIAO perturbation method. The TSNMRS are visualized as iso-chemical-shielding surfaces (ICSS) of different sign and size. Coincident experimental and computed 1H/13C chemical shifts afforded the possibility to decide from the TSNMRSs at hand on both the existence and the size of homoaromaticity in the molecules studied.
Y1  - 2009
UR  - http://www.sciencedirect.com/science/journal/00404020
U6  - https://doi.org/10.1016/j.tet.2009.04.063
SN  - 0040-4020
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
A1  - Seidl, Peter R.
T1  - Visualization and quantification of the anisotropic effect of C=C double bonds on 1H NMR spectra of highly congested hydrocarbons-indirect estimates of steric strain
N2  - The anisotropic effect of the olefinic C=C double bond has been calculated by employing the NICS (nucleus independent chemical shift) concept and visualized as an anisotropic cone by a through space NMR shielding grid. Sign and size of this spatial effect on 1H chemical shifts of protons in norbornene, exo- and endo-2-methylnorbornenes, and in three highly congested tetracyclic norbornene analogs have been compared with the experimental 1H NMR spectra as far as published. 1H NMR spectra have also been calculated at the HF/6-31G* level of theory to get a full, comparable set of proton chemical shifts. Differences between ;(1H)/ppm and the calculated anisotropic effect of the C=C double bond are discussed in terms of the steric compression that occurs in the compounds studied.
Y1  - 2008
UR  - http://pubs.acs.org/doi/full/10.1021/jp801063t
U6  - https://doi.org/10.1021/Jp801063t
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Szatmári, István
A1  - Lázár, László
A1  - Koch, Andreas
A1  - Heydenreich, Matthias
A1  - Fulop, Ferenc
T1  - Visualization and quantification of anisotropic effects on the 1H NMR spectra of 1,3-oxazino[4,3- alpha]isoquinolines - indirect estimates of steric compression
N2  - The anisotropic effects of the phenyl, alpha- and beta-naphthyl moieties in four series of 1,3-oxazino[4,3- a]isoquinolines on the H-1 chemical shifts of the isoquinoline protons were calculated by employing the Nucleus Independent Chemical Shift (NICS) concept and Visualized as anisotropic cones by a through-space NMR shielding grid. The signs and extents of these spatial effects on the H-1 chemical shifts of the isoquinoline protons were compared with the experimental H-1 NMR spectra. The differences between the experimental delta (H-1)/ppm values and the calculated anisotropic effects of the aromatic moieties are discussed in terms of the steric compression that occurs in the Compounds studied.
Y1  - 2009
U6  - https://doi.org/10.1016/j.tet.2009.07.038
SN  - 0040-4020
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Ushakov, Igor A.
A1  - Meshcheryakov, Vladimir I.
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - Variable temperature NMR and theoretical study of the stereodynamics of 5-trifluoromethylsulfonyl-1,3,5- dioxaazinane : Perlin effect subject to heteroatom substitution
N2  - Multinuclear dynamic NMR spectroscopy of 5-trifluoromethylsulfonyl-1,3,5-dioxaazinane (4) revealed the existence of two close in energy chair conformers with differently oriented CF3 groups with respect to the ring. Of the two alternative routes for their interconversion, the ring inversion path with intermediate formation of the corresponding 2,5-twist-conformer is preferred, with the energy barrier of 11.2 kcal/mol in excellent agreement with the experimental value (11.7 kcal/mol). The Perlin effect is studied experimentally and calculated theoretically for all CH2 groups and found to be subject to the nature of the adjacent heteroatoms O and N, respectively.
Y1  - 2008
ER  - 
TY  - JOUR
A1  - Szatmari, Istvan
A1  - Heydenreich, Matthias
A1  - Koch, Andreas
A1  - Fulop, Ferenc
A1  - Kleinpeter, Erich
T1  - Unexpected isomerization of new naphth[1,3]oxazino[2,3-a] isoquinolines in solution, studied by dynamic NMR and supported by theoretical DFT computations
JF  - Tetrahedron
N2  - Through the reactions of 1-aminomethyl-2-naphthol and substituted 1-aminobenzyl-2-naphthols with 3,4-dihydroisoquinoline or 6,7-dimethoxy-3,4-dihydroisoquinoline under microwave conditions, naphth[1,2-e][1,3]oxazino[2,3-a]-isoquinoline derivatives were prepared in good yields. The latter reaction was extended by using 2-aminoarylmethyl-1-naphthols, leading to isomeric naphth-[2,1-e][1,3]oxazino[2,3-a] isoquinolines. Beside the detailed NMR spectroscopic and theoretical study of both stereochemistry and dynamic behaviour of these new conformational flexible heterocyclic ring systems an unexpected dynamic process between two diastereomers was observed in solution, studied by variable temperature H-1 NMR spectroscopy and the mechanism proved by theoretical DFT computations.
KW  - 3,4-Dihydroisoquinoline
KW  - Aminonaphthol
KW  - Dynamic NMR spectroscopy
KW  - DFT calculations
KW  - Conformational analysis
Y1  - 2013
U6  - https://doi.org/10.1016/j.tet.2013.06.094
SN  - 0040-4020
VL  - 69
IS  - 35
SP  - 7455
EP  - 7465
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - Trisannelated benzenes - Aromatic molecules or 1,3,5-cyclohexatriene derivatives subjected to magnetic properties
N2  - The through space NMR shielding (TSNMRS) values of two tricyclobutabenzene (TCBB) derivatives 2, of the corresponding hexamethylene and hexaoxo TCBB derivatives 3, of [4n]annuleno[4n + 2]annulene 5 and of its tricyclobutadiene parent compound 4 have been ab initio calculated by the GIAO perturbation method employing the nucleus- independent chemical shift (NICS) concept of Paul von Ragué Schleyer, and visualized as iso-chemical shielding surfaces (ICSS). TSNMRS values can be successfully employed to quantify and visualize the aromaticity of the central, and in 5 also of the terminal benzene ring moieties.
Y1  - 2008
U6  - https://doi.org/10.1016/j.theochem.2008.02.013
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Ushakov, Igor A.
A1  - Meshcheryakov, Vladimir I.
A1  - Schilde, Uwe
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - The stereodynamics of 3,5-bis(trifluoromethylsulfonyl)-1,3,5-oxadiazinane and 1,3,5- tris(trifluoromethylsulfonyl)-1,3,5-triazinane- an experimental and theoretical study
N2  - Multinuclear dynamic NMR spectroscopy of 3,5-bis(trifluoromethylsulfonyl)-1,3,5-oxadiazinane (3) revealed the existence of two conformers with differently oriented CF3 groups with respect to the ring, and two dynamic processes: ring inversion and restricted rotation about the N-S bond. Two transition states connecting the two conformers and corresponding to clockwise and counterclockwise rotations about the N-S bond were found; the calculated activation barriers of about 12 kcal/mol are in excellent agreement with those measured experimentally for the related molecule 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane (1). X-ray analysis proved the existence of the symmetric isomer of 3, which is the minor isomer in solutions but the only one in the crystal due to packing effects. The normal Perlin effect (JCHax < JCHeq)observed for 2(6)-CH2 in 3, whereas the reversed Perlin effect was found for the 4-CH2 group in 3 as well as for all CH2 groups in 1 both experimentally and theoretically. The latter effect in compounds 1, 3, and 1- (methylsulfonyl)-3,5-bis(trifluoromethylsulfonyl)-1,3,5-triazinane (2) can be considered as a genuine reverse Perlin effect since larger values of 1JCH are observed for longer C-H bonds.
Y1  - 2007
UR  - http://www.sciencedirect.com/science/article/pii/S0040402007016389
U6  - https://doi.org/10.1016/j.tet.2007.09.041
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - The multiple bond character of the carbon-boron bond in boron trapped N-heterocyclic carbenes (NHCs) and cyclic(alkyl)(amino) carbenes (CAACs) on the magnetic criterion
JF  - Tetrahedron
N2  - Geometry, 11B, 13C chemical shifts and the spatial magnetic properties (Through-Space NMR Shieldings -TSNMRS) of both cations and anions of boron-trapped N-heterocyclic carbenes (NHCs) and cyclic (alkyl)(amino)carbenes (CAACs) and of the corresponding diborane/diborene/diboryne dis-carbene adducts have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept; the TSNMRS results are visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction. The ICSS of the TSNMRS (actually the anisotropy effects measurable in 1H NMR spectroscopy) are employed to qualify and quantify the present multiple bond character of the Carbene-Boron bond in the trapped NHCs and CAACs. Results are confirmed by bond length and 11B/13C chemical shift variations. Thus the partial multiple bond character of the Carbene-Boron bond cannot be expressed by the arrow of weak, much longer dative bonds and should be omitted as in other covalent lone pair-it or triel bonds. & COPY; 2023 Elsevier Ltd. All rights reserved.
KW  - NHCs
KW  - CAACs
KW  - Multiple NHC(CAAC)-Boron bonds
KW  - Through -space NMR
KW  - shieldings (TSNMRS)
KW  - NICS
KW  - Anisotropy effect
KW  - Ring current effect
Y1  - 2023
U6  - https://doi.org/10.1016/j.tet.2023.133469
SN  - 0040-4020
SN  - 1464-5416
VL  - 140
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Scholl, S.
A1  - Koch, Andreas
A1  - Henning, Dietrich
A1  - Kempter, Gerhard
A1  - Kleinpeter, Erich
T1  - The influence of structure and lipophilicity of hydantoin derivatives on anticonvulsant activity
Y1  - 1999
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  - The anisotropic effect of functional groups in H-1 NMR spectra is the molecular response property of spatial NICS-the frozen conformational equilibria of 9-arylfluorenes
JF  - Tetrahedron
N2  - Rotation about the single bond adjoining the aryl and fluorene moieties in 9-arylfluorenes can be frozen out on the NMR timescale if methyl groups are located at either one or both of the ortho positions of the aryl substituent. In the ground-state of these rotamers, the planes of the aryl and fluorene moieties are perpendicular to each other and the methyl substituents are consequently positioned either above the fluorene moiety or in-plane with it; thus, the methyl protons are either shielded or deshielded, respectively, due to the ring current effect of the fluorene moiety. This anisotropic effect on the H-1 chemical shifts of the methyl protons has been quantified on the basis of through-space NMR shieldings (TSNMRS) and subsequently Delta delta(calcd) compared with the experimentally observed chemical shift differences, Delta delta(exp). In this context, the experimental anisotropic effects of functional groups in the H-1 NMR have proven to quantitatively be the molecular response property of theoretical spatial nucleus independent chemical shieldings (NICS). Differences between Delta delta(calcd) and Delta delta(exp) were, for the first time, also quantified as arising from steric compression.
KW  - Through-space NMR shieldings (TSNMRS)
KW  - Spatial NICS
KW  - Anisotropic effect
KW  - Iso-chemical-shielding surfaces (ICSS)
KW  - 9-Arylfluorenes
Y1  - 2011
U6  - https://doi.org/10.1016/j.tet.2011.06.005
SN  - 0040-4020
VL  - 67
IS  - 32
SP  - 5740
EP  - 5743
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - The anisotropic effect of functional groups in 1H NMR spectra is the molecular response property of spatial NICS-the frozen conformational equilibria of 9-arylfluorenes
N2  - Rotation about the single bond adjoining the aryl and fluorene moieties in 9-arylfluorenes can be frozen out on the NMR timescale if methyl groups are located at either one or both of the ortho positions of the aryl substituent. In the ground-state of these rotamers, the planes of the aryl and fluorene moieties are perpendicular to each other and the methyl protons are either shielded or deshielded, respectively, due to the ringe current effect of the fluorene moiety. This anisotropic effect on the 1H chemical shifts of the methyl protons has been quantified on the basis of through- space NMR shieldings (TSNMRS) and subsequently _______ compared with the experimentally observed chemical shift differences _____. In this context, the experimental anisotropic effects of functional groups in the !H NMR have proven to quantitatively be the molecular response property of theoretical spatial nucleus independent chemical shieldings (NICS). Differences between _______ and _____ were, for the first time, also quantified as arising from steric compression.
Y1  - 2011
UR  - http://www.sciencedirect.com/science/article/pii/S0040402011008507 (13.9.13)
SN  - 0040-4020
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - The 13 C chemical shift and the anisotropy effect of the carbene electron-deficient centre
BT  - simple means to characterize the electron distribution of carbenes
JF  - Magnetic resonance in chemistry
N2  - Both the C-13 chemical shift and the calculated anisotropy effect (spatial magnetic properties) of the electron-deficient centre of stable, crystalline, and structurally characterized carbenes have been employed to unequivocally characterize potential resonance contributors to the present mesomerism (carbene, ylide, betaine, and zwitter ion) and to determine quantitatively the electron deficiency of the corresponding carbene carbon atom. Prior to that, both structures and C-13 chemical shifts were calculated and compared with the experimental delta(C-13)/ppm values and geometry parameters (as a quality criterion for obtained structures).
KW  - C-13 chemical shift
KW  - carbenes
KW  - zwitterions
KW  - carbene electron deficiency
KW  - nucleus-independent chemical shifts (NICS)
KW  - through space NMR shieldings
KW  - (TSNMRS)
Y1  - 2019
U6  - https://doi.org/10.1002/mrc.4979
SN  - 0749-1581
SN  - 1097-458X
VL  - 58
IS  - 3
SP  - 280
EP  - 292
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Klinka, Karel D.
A1  - Balentova, Eva
A1  - Bernát, Juraj
A1  - Imrich, Jan
A1  - Vavrusova, Martina
A1  - Kleinpeter, Erich
A1  - Pihlaja, Kalevi
A1  - Koch, Andreas
T1  - Tautomerism, regioisomerism, and cyclization reactions of acridinyl thiosemicarbazides
N2  - The regioselectivities of methyl- and phenylhydrazine with acridin-9-yl isothiocyanate (thus yielding thiosemicarbazides with acridine substituted on the urea-type side) were examined. Methythydrazine regioselectivity was high with the alpha-nitrogen atom overwhelmingly more nucleophilic than the beta-nitrogen atom; phenylhydrazine regioselectivity was poor but varied with the solvent and only in the case of ethanol was nucleophilic predominance of the alpha-nitrogen atom pronounced. Of note, whilst both phenyl thiosemicarbazides were present in solution only as spiro forms, the methyl product was present as an equilibrium mixture of open-chain and spiro thiosemicarbazides. Reactions on the NH2 blocked analogue of methyl acridin-9-ylthiosemicarbazide (1-isopropylidene-2- methylthiosemicarbazide) were also examined. Interestingly, present in the starting material itself was a structural motif of novelty wherein a triazolethione represented the major species of an equilibrium between cyclic and open-chain forms
Y1  - 2006
UR  - http://www3.interscience.wiley.com/journal/121521817/toc
U6  - https://doi.org/10.1002/jhet.5570430317
SN  - 0022-152X
ER  - 
TY  - JOUR
A1  - Neuvonen, Kari
A1  - Neuvonen, Helmi
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - Taft equation in the light of NBO computations introduction of a novel polar computational substituent constant scale sigma(q)* for alkyl groups
JF  - Computational and theoretical chemistry
N2  - The validity of the Taft equation: log(k(R)/k(CH3)) = rho*sigma* + delta E-S was studied with the aid of NBO computational results concerning cyclohexyl esters RCOOC6H11 [R = Methyl, Ethyl, n-Propyl, Isopropyl, n-Butyl, Isobutyl, sec-Butyl, tert-Butyl, Neopentyl, CH(CH2CH3)(2), CH(CH3)C(CH3)(3), C(CH3)(2)CH2CH3, C(CH3)(2)C(CH3)(3), CH(CH3)(Np), CH(iPr)(tBu), C(Me)(Et)(iPr), C(Et)(2)(tBu) or C(Et)(iPr)(tBu)]. It was proved that the sigma*(alkyl) value is a composite substitutent constant including the polar and steric contributions. A novel computational sigma(q)* substituent constant scale is presented based on the NBO atomic charges of the alpha-carbon and the computational total steric exchange energies E(ster) of the cyclohexyl esters specified above. The method used offers a useful way to calculate sigma*(alkyl) values for alkyl groups for which experimental Taft's polar sigma* parameters are not available.
KW  - NBO analysis
KW  - Taft equation
KW  - Polar substituent constant
KW  - Steric effect
Y1  - 2012
U6  - https://doi.org/10.1016/j.comptc.2011.11.044
SN  - 2210-271X
VL  - 981
IS  - 2
SP  - 52
EP  - 58
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Neuvonen, Kari
A1  - Neuvonen, Helmi
A1  - Koch, Andreas
T1  - Taft equation in the light of NBO computations : Introduction of a novel polar computational substituent constant scale for alkyl groups
Y1  - 2012
SN  - 2210-271X
ER  - 
TY  - JOUR
A1  - Virta, P.
A1  - Koch, Andreas
A1  - Roslund, M. U.
A1  - Mattjus, P.
A1  - Kleinpeter, Erich
A1  - Kronberg, L.
A1  - Sjoholm, R.
A1  - Klika, Karel D.
T1  - Synthesis, characterisation and theoretical calculations of 2,6-diaminopurine etheno derivatives
N2  - Four derivatives of 2,6-diaminopurine (1) were synthesised and characterised. When 1 was reacted with chloroacetaldehyde, 5-aminoimidazo[2,1- i] purine (2), 9-aminoimidazo[2,1-b]purine (3), 9-aminoimidazo[1,2- a]purine (4) and diimidazo[2,1-b: 2', 1'-i]purine (5) were formed. The purified products (3 - 5) were fully characterised by MS, complete NMR assignments as well as fluorescence and UV spectroscopy. The purified, isolated yields of these products ( 3 - 5) varied from 2.5 to 30%. The relative stability of different tautomers was investigated by theoretical calculations. Fluorescence characteristics are also discussed and compared to the starting material 1 and a reference molecule 2-aminopurine
Y1  - 2005
SN  - 1477-0520
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  -