TY  - JOUR
A1  - Belasri, Khadija
A1  - Topal, Leila
A1  - Heydenreich, Matthias
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
A1  - Fulop, Ferenc
A1  - Szatmari, Istvan
T1  - Synthesis and conformational analysis of naphthoxazine-fused phenanthrene derivatives
JF  - Molecules
N2  - The synthesis of new phenanthr[9,10-e][1,3]oxazines was achieved by the direct coupling of 9-phenanthrol with cyclic imines in the modified aza-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-e][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 ortho-quinone methides (o-QMs) was calculated, the geometries obtained were compared with the experimentally determined NMR structures, and thereby, the regioselectivity of the reactions has been assigned.
KW  - modified Mannich reaction
KW  - cyclic imines
KW  - [4+2] cycloaddition
KW  - NMR
KW  - spectroscopy
KW  - conformational analysis
KW  - DFT calculations
Y1  - 2020
U6  - https://doi.org/10.3390/molecules25112524
SN  - 1420-3049
VL  - 25
IS  - 11
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Paz, Cristian
A1  - Heydenreich, Matthias
A1  - Schmidt, Bernd
A1  - Vadra, Nahir
A1  - Baggio, Ricardo
T1  - Three new dihydro-beta-agarofuran sesquiterpenes from the seeds of Maytenus boaria
JF  - Acta Crystallographica Section C
N2  - As part of a project studying the secondary metabolites extracted from the Chilean flora, we report herein three new beta-agarofuran sesquiterpenes, namely (1S,4S,5S,6R,7R,8R,9R,10S)-6-acetoxy-4,9-dihydroxy-2,2,5a,9-tetramethyloctahydro-2H-3,9a-methanobenzo[b] oxepine-5,10-diylbis(furan-3-carboxylate), C27H32O11, (II), (1S,4S,5S,6R,7R,9S,10S)-6-acetoxy-9-hydroxy-2,2,5a, 9-tetramethyloctahydro-2H-3,9a-methanobenzo[ b] oxepine-5,10-diyl bis(furan-3-carboxylate), C27H32O10, (III), and (1S,4S,5S,6R,7R,9S,10S)-6-acetoxy-10-(benzoyloxy)-9-hydroxy-2,2,5a,9-tetramethyloctahydro-2H-3,9a-methanobenzo[b]oxepin-5-yl furan-3-carboxylate, C29H34O9, (IV), obtained from the seeds of Maytenus boaria and closely associated with a recently published relative [Paz et al. (2017). Acta Cryst. C73, 451-457]. In the (isomorphic) structures of (II) and (III), the central decalin system is esterified with an acetate group at site 1 and furoate groups at sites 6 and 9, and differ at site 8, with an OH group in (II) and no substituent in (III). This position is also unsubstituted in (IV), with site 6 being occupied by a benzoate group. The chirality of the skeletons is described as 1S, 4S, 5S, 6R, 7R, 8R, 9R, 10S in (II) and 1S, 4S, 5S, 6R, 7R, 9S, 10S in (III) and (IV), matching the chirality suggested by NMR studies. This difference in the chirality sequence among the title structures (in spite of the fact that the three skeletons are absolutely isostructural) is due to the differences in the environment of site 8, i.e. OH in (II) and H in (III) and (IV). This diversity in substitution, in turn, is responsible for the differences in the hydrogen-bonding schemes, which is discussed.
KW  - Celastraceae
KW  - Maytenus boaria
KW  - sesquiterpene
KW  - dihydro-beta-agarofuran
KW  - crystal structure
KW  - NMR
KW  - DSC
Y1  - 2018
U6  - https://doi.org/10.1107/S2053229618005429
SN  - 2053-2296
VL  - 74
SP  - 564
EP  - 570
PB  - International Union of Crystallography
CY  - Chester
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Moskalik, Mikhail Yu
A1  - Heydenreich, Matthias
A1  - Kleinpeter, Erich
T1  - Conformational equilibrium and dynamic behavior of bis-N-triflyl substituted 3,8-diazabicyclo[3.2.1]octane
JF  - Magnetic resonance in chemistry
N2  - Restricted rotation about the N-S partial double bonds in a bis-N-triflyl substituted 3,8-diazabicyclo[3.2.1]octane derivative 1 has been frozen at low temperature (Delta G* = 11.6 kcal mol(-1)), and the existence of all four rotamers about the two N-S bonds, 3-in, 8-in, 3-in, 8-out, 3-out, 8-in, and 3-out, 8-out, respectively, proved experimentally by NMR spectroscopy and theoretically by DFT and MP2 calculations. Copyright (C) 2014 John Wiley & Sons, Ltd.
KW  - NMR
KW  - H-1
KW  - C-13
KW  - F-19
KW  - Dynamic NMR
KW  - Conformational equilibrium
KW  - restricted N-S rotation
Y1  - 2014
U6  - https://doi.org/10.1002/mrc.4086
SN  - 0749-1581
SN  - 1097-458X
VL  - 52
IS  - 8
SP  - 448
EP  - 452
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Csuetoertoeki, Renata
A1  - Szatmari, Istvan
A1  - Koch, Andreas
A1  - Heydenreich, Matthias
A1  - Kleinpeter, Erich
A1  - Fueloep, Ferenc
T1  - Synthesis and conformational analysis of new naphth[1,2-e][1,3]oxazino[3,4-c]quinazoline derivatives
JF  - Tetrahedron
N2  - A new highly functionalized aminonaphthol derivative, 1-(amino(2-aminophenyl)methyl)-2-naphthol (4), was synthesized by the reaction of 2-naphthol, 2-nitrobenzaldehyde and tert-butyl carbamate or benzyl carbamate, followed by reduction and/or removal of the protecting group. The aminonaphthol derivative thus obtained was converted in ring-closure reactions with formaldehyde. benzaldehyde and/or phosgene to the corresponding naphth[1,2-e][1,3]oxazino[3,4-c]quinazoline derivatives. The conformational analysis of some derivatives by NMR spectroscopy and accompanying molecular modelling are also reported.
KW  - Naphthoxazinoquinazolines
KW  - NMR
KW  - Conformational analysis
KW  - DFT calculations
KW  - Hammett-Brown plots
Y1  - 2011
U6  - https://doi.org/10.1016/j.tet.2011.08.074
SN  - 0040-4020
VL  - 67
IS  - 44
SP  - 8564
EP  - 8571
PB  - Elsevier
CY  - Oxford
ER  -