TY  - JOUR
A1  - Sarodnick, Gerhard
A1  - Linker, Torsten
A1  - Heydenreich, Matthias
A1  - Koch, Andreas
A1  - Starke, Ines
A1  - Fürstenberg, Sylvia
A1  - Kleinpeter, Erich
T1  - Quinoxalines XV : convenient synthesis and structural study of pyrazolo[1,5-alpha]quinoxalines
N2  - A series of aryloxymethylquinoxaline oximes, hitherto unknown and synthesized from the corresponding aldehydes, afforded in only one step pyrazolo[1,5-;]quinoxalines in the presence of acetic anhydride at high temperatures. A formal [3,5]-sigmatropic rearrangement was proposed as the mechanistic rationale for this unprecedented transformation. Saponification with potassium hydroxide furnished the free phenol derivatives which were studied by NMR spectroscopy and accompanying theoretical DFT calculations, establishing intramolecular hydrogen bonding and the spatial magnetic properties. Additionally, mass spectrometric fragmentation was investigated by B/E-linked scans and collision-induced dissociation experiments. The fragmentation pattern devoted a new gas phase rearrangement process, which proved to be unique and characteristic for pyrazolo[1,5-;]quinoxalines.
Y1  - 2009
UR  - http://pubs.acs.org/journal/joceah
U6  - https://doi.org/10.1021/Jo802398g
SN  - 0022-3263
ER  - 
TY  - JOUR
A1  - Kempter, Gerhard
A1  - Sarodnick, Gerhard
T1  - Synthese von Pyrazolyl- und Pyrimidinylchinoxalinen
Y1  - 1991
ER  - 
TY  - JOUR
A1  - Woller, Jochen
A1  - Spindler, Jürgen
A1  - Sarodnick, Gerhard
A1  - Kempter, Gerhard
T1  - Synthese neuer Thieno- und Pyrazolopyridine als potentielle Pharmaka
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Sarodnick, Gerhard
A1  - Hilfert, Liane
A1  - Kempter, Gerhard
A1  - Kleinpeter, Erich
T1  - Reactin of 2-(halogenomethyl)-quinoxalines and quinolines with hydroxybenzoic acids and their esters
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Hilfert, Liane
A1  - Sarodnick, Gerhard
A1  - Kempter, Gerhard
A1  - Kleinpeter, Erich
T1  - 1H, 13C and 15 N NMR study and molecular modelling of 2,3- disubstituted quinoxalines with sterically hinderered aromatic and heteroaromatic substituents
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Sarodnick, Gerhard
A1  - Linker, Torsten
T1  - Quinoxalines X : a new and convenient synthesis of 1H-Pyrazolo[3,4-b] quinoxalines (Flavazoles)
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Sarodnick, Gerhard
A1  - Heydenreich, Matthias
A1  - Linker, Torsten
A1  - Kleinpeter, Erich
T1  - Quinoxalines : Part 12: Synthesis and structural study of 1-(thiazol-2-yl)-1H-pyrazolo[3,4-b]quinoxalines - the dehydrogenative cyclization with hydroxylamine hydrochloride
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Starke, I.
A1  - Sarodnick, Gerhard
A1  - Ovcharenko, V. V.
A1  - Pihlaja, Kalevi
A1  - Kleinpeter, Erich
T1  - Quinoxalines : Part 13: Synthesis and mass spectrometric study of aryloxymethylquinoxalines and benzo[b]furylquinoxalines
N2  - A series of new aryloxymethylquinoxalines, benzo[b]- and naphtho[2,1-b] fury] quinoxalines, possessing potential biological activity, was prepared, characterized by IR and NMR spectroscopy and their electron ionization (EI) mass spectra studied in detail. The aryloxymethylquinoxalines were obtained by reacting halogenomethylquinoxalines with bifunctional O-nucleophiles. The benzo[b]furylquinoxalines and naphtho[2, I -b]furylquinoxalines were prepared via two routes, which differed in the order of the two cyclization steps involved in the syntheses. The composition of the ions obtained by El mass spectrometry were determined by accurate mass measurements and the fragmentation pathways clarified by B/E linked scans and collision induced dissociation. The mass spectrometric behaviour of the compounds studied as to the possible loss of OH' radicals proved to be very characteristic. (C) 2004 Elsevier Ltd. All rights reserved
Y1  - 2004
SN  - 0040-4020
ER  - 
TY  - JOUR
A1  - Heydenreich, Matthias
A1  - Koch, Andreas
A1  - Sarodnick, Gerhard
A1  - Kleinpeter, Erich
T1  - Quinoxalines XIV : Synthesis, H-1, C-13, N-15 NMR spectroscopic, and quantum chemical study of 1H-pyrazolo[3,4- b]quinoxalines (flavazoles)
N2  - The synthesis of a series of 1H-pyrazolo[3,4-b]quinoxalines (flavazoles) by acylation, alkylation, halogenation, and aminomethylation of the parent compound is reported and their structure is investigated by H-1, C-13 and N-15 NMR spectroscopy. The restricted rotation about the partial C, N double bond of the N-acyl derivatives 7-10 is studied by dynamic NMR spectroscopy and the barriers to rotation are determined. In order to assign unequivocally the 15 N chemical shifts of N-4 and N-9, in case of 3-substituted flavazoles, exemplary the H-1, C-13, and N-15 NMR chemical shifts of 34, 35, and 39 are also theoretically calculated by quantum chemical methods [ab initio at different levels of theory (HF/6-3G* and B3LYP/6-31G*)]. (C) 2005 Elsevier Ltd. All rights reserved
Y1  - 2005
SN  - 0040-4020
ER  -