@article{SarodnickLinkerHeydenreichetal.2009,
  author    = {Sarodnick, Gerhard and Linker, Torsten and Heydenreich, Matthias and Koch, Andreas and Starke, Ines and F{\"u}rstenberg, Sylvia and Kleinpeter, Erich},
  title     = {Quinoxalines XV : convenient synthesis and structural study of pyrazolo[1,5-alpha]quinoxalines},
  issn      = {0022-3263},
  doi       = {10.1021/Jo802398g},
  year      = {2009},
  abstract  = {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.},
  language  = {en}
}
@article{KleinpeterFrank2009,
  author    = {Kleinpeter, Erich and Frank, Andrea},
  title     = {Distinction of Push,pull effect and steric hindrance in disubstituted alkynes},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2009.03.075},
  year      = {2009},
  abstract  = {The push,pull effect in two series of disubstituted alkynes was studied at the DFT level [B3LYP/6-311G(d)] by application of the 13C chemical shift differences (GIAO) between the alkyne carbon atoms (Delta delta (C C)), the charge difference between these carbons (Delta q(C C)), the occupation quotient (NBO) of anti-bonding pi*, and bonding pi orbitals (pi*(C C)/pi(C C)) and the bond length (d(C C)) of the C C triple bond. The linear dependence of d(C C) versus pi*(C C)/pi(C C) quantifies changes in the push,pull effect while deviations from the latter correlation indicate and ascertain quantitatively to what extent steric hindrance restricts the strain-less conjugation of the C C triple bond pi- orbitals in the disubstituted alkynes.},
  language  = {en}
}
@article{BoehmTomaszcikovaImrichetal.2009,
  author    = {B{\"o}hm, Stanislav and Tomaszcikov{\´a}, Jana and Imrich, J{\´a}n and Danihel, Ivan and Kristian, Pavol and Koch, Andreas and Kleinpeter, Erich and Klika, Karel D.},
  title     = {Computational study to assign structure, tautomerism, E/Z and s-cis/s-trans isomerism, pi-delocalization, partial aromaticity, and the ring size of 1,3-thiazolidin-4-ones and 1,3-thiazin-4-ones formed from thiosemicarbazides},
  issn      = {0166-1280},
  year      = {2009},
  abstract  = {A set of structures encompassing 1-(9-acridinyl)thiosemicarbazide and its 2-methyl derivative together with their various tautomeric structures; the 5-membered ring 1,3-thiazolidin-4-one products resulting from the reaction of 1- (9-acridinyl)thiosemicarbazide and its 2-methyl derivative with dimethyl acetylenedicarboxylate (DMAD) together with the alternative 6-membered ring isomeric reaction products as well as other potential isomeric structures; and the 6- membered ring 1,3-thiazin-4-one product resulting from the reaction of 2-methyl-1-(9-acridinyl)thiosemicarbazide with methyl propiolate (MP) together with the alternative 5-membered ring isomeric reaction product were all extensively studied by molecular modeling calculations using DFT at the B3LYP/6-31G(d,p) level of theory. The ring-chain tautomerism of the thiosemicarbazides, the regio- and stereoselectivity of the reactions, the adopted conformations and E/Z configurations of the products, the prototropic tautomerism of all the compounds, and the reasons for the predominance of the s-cis conformation of the Z configuration of the 1,3-thiazolidin-4-one product in particular were all extensively analyzed. Comparison of the modeled structures were also made to the 1,3-thiazolidin-4-one and 1,3-thiazin-4-one structures of the methyl derivative as well as 1-(9-acridinyl)thiosemicarbazide available from X-ray crystallographic analysis. Tactics utilizing spectroscopic methods {IR frequencies (;) and NMR chemical shifts (;), scalar coupling constants (J), and NOEs (;)} in conjunction with molecular modeling calculations of the spectral parameters {frequency calculations (;) and NMR ; using the GIAO method and J by calculation of the Fermi contact term} were evaluated in terms of proving 5- or 6-membered ring formation.},
  language  = {en}
}
@article{ModarresiAlamAlsadatAmiraziziBagherietal.2009,
  author    = {Modarresi-Alam, Ali Reza and Alsadat Amirazizi, Homeyra and Bagheri, Hajar and Bijanzadeh, Hamid-Reza and Kleinpeter, Erich},
  title     = {Dynamic 1H NMR spectroscopic study of the ring inversion in N-sulfonyl morpholines-studies on N-S interactions},
  issn      = {0022-3263},
  year      = {2009},
  abstract  = {The effect of the exocyclic conjugation, via d;p orbital interaction and/or negative hyperconjugation (anomeric effect) of the N;S bond, on the inversion of the morpholine ring in some N-arylsulfonyl morpholines is studied by variable-temperature 1H NMR spectroscopy in different solvents. The observed free energy barriers are 9.2;10.3 kcal mol;1; the lower values were obtained with increasing conjugation (substituents of higher electron withdrawing power) along the series. The barrier to ring inversion of 1e was solvent independent. X-ray data of compounds 1b,d reveal the chair conformation of the six-membered ring, the flattened pyramidal orientation of the ring nitrogen atom, and the sulfonyl group in equatorial position with the plane containing the Caryl;S;N bond perpendicular to the plane of the benzene ring. In addition, the sulfonamide group prefers a conformation with the S;C bond antiperiplanar with respect to the nitrogen atom lone pair and the ;CH2;N;CH2; moieties in staggered conformation with the S;O bonds of the SO2 group.},
  language  = {en}
}
@article{KleinpeterFrank2009,
  author    = {Kleinpeter, Erich and Frank, Andrea},
  title     = {Quantification of the push-pull effect in substituted alkynes : evaluation of +/- I/+/- M substituent effects in terms of C C bond length variation},
  issn      = {1089-5639},
  doi       = {10.1021/Jp9024359},
  year      = {2009},
  abstract  = {C-13 chemical shifts of alkynes, published to date, were computed at the DFT (B3LYP/6-311G*) level of theory and compared with the experimental delta values, and the agreement was employed as a measure of quality for the underlying structures. For the corresponding global minima structures, thus obtained, the occupation quotients of antibonding pi* and bonding pi orbitals (pi*(C C)/pi(C C)) and the bond lengths (d(C C)) of the central C C triple bond were computed and correlated to each other. The linear dependence obtained for the two push-pull parameters d(C C) and pi*(C C)/pi(C C) quantifies changes in the push-pull effect of substituents while deviations from the best line of fit indicate and ascertain quantitatively to what extend the inductive (+/-l) substituent effect changes with respect to the bond length of the C C triple bond.},
  language  = {en}
}
@article{KleinpeterSzatmariLazaretal.2009,
  author    = {Kleinpeter, Erich and Szatm{\´a}ri, Istv{\´a}n and L{\´a}z{\´a}r, L{\´a}szl{\´o} and Koch, Andreas and Heydenreich, Matthias and Fulop, Ferenc},
  title     = {Visualization and quantification of anisotropic effects on the 1H NMR spectra of 1,3-oxazino[4,3- alpha]isoquinolines - indirect estimates of steric compression},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2009.07.038},
  year      = {2009},
  abstract  = {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.},
  language  = {en}
}
@article{FechnerKramerKleinpeteretal.2009,
  author    = {Fechner, Mabya and Kramer, Markus and Kleinpeter, Erich and Koetz, Joachim},
  title     = {Polyampholyte-modified ionic microemulsions},
  issn      = {0303-402X},
  doi       = {10.1007/s00396-009-2074-4},
  year      = {2009},
  abstract  = {This paper is focused on the influence of added polyampholyte, namely poly(N,N;-diallyl-N,N;- dimethyl-alt-maleamic carboxylate) on the inverse micellar phase range of the pseudo-ternary system consisting of toluene-pentanol (1:1)/SDS/water in dependence on the pH value and the temperature. Investigations on phase behavior have revealed that a greater extension in direction to the water-rich corner can be found at pH 4 compared to pH 9. In order to understand changes in the microstructure, polymer-surfactant interactions in dependence on pH have been examined by means of diffusion-ordered spectroscopy, differential scanning calorimetry, as well as conductivity measurements. The results have proven that the present microemulsion consists of water-in-oil droplets, with the polyampholyte located more in the inner core of the water droplets at pH 9 rather than at the interphase of the surfactant film at pH 4.},
  language  = {en}
}
@article{StroehlThomasRadegliaetal.1992,
  author    = {Str{\"o}hl, D. and Thomas, Steffen and Radeglia, R. and Brunn, J. and Kleinpeter, Erich},
  title     = {13C-NMR-Untersuchungen von Substituenteneffekten in mehrfach substituierten Benz-und Naphthalenderivaten ; Inkrementberechnungen der 13C-chemischen Verschiebungen},
  year      = {1992},
  language  = {de}
}
@article{KleinpeterHartmannSchrothetal.1992,
  author    = {Kleinpeter, Erich and Hartmann, J{\"u}rgen and Schroth, W. and Hofer, O. and Kalchhauser, H. and Wurz, G.},
  title     = {Synthesis and conformational behaviour of Ditosyldiaza[2.2]orthometacyclophanes},
  year      = {1992},
  language  = {en}
}
@article{GrielStroehlJeschkeitetal.1992,
  author    = {Griel, C. and Str{\"o}hl, D. and Jeschkeit, H. and Kleinpeter, Erich},
  title     = {Synthetische und NMR-spektroskopische Untersuchungen der Benzzyl-aminaddition an N-Maleyl- aminos{\"a}urederivaten},
  year      = {1992},
  language  = {de}
}
@article{KleinpeterStohssSchroth1992,
  author    = {Kleinpeter, Erich and Stohß, S. and Schroth, W.},
  title     = {Stereochemistry and complexational behaviour of dibenzo-crown ethers},
  year      = {1992},
  language  = {en}
}
@article{ArrietaBeyerLehmannetal.1992,
  author    = {Arrieta, A. and Beyer, L. and Lehmann, J. and Dargatz, M. and Kleinpeter, Erich},
  title     = {Synthese und 1H-NMR-spektroskopische Untersuchungen neuer Curcuminanaloga},
  year      = {1992},
  language  = {de}
}
@article{KleinpeterDargatz1992,
  author    = {Kleinpeter, Erich and Dargatz, M.},
  title     = {Eine 2D-INEPT-Variante zur Detektierung wenig empfindlicher Kerne},
  year      = {1992},
  language  = {de}
}
@article{KleinpeterThomasUhligetal.1993,
  author    = {Kleinpeter, Erich and Thomas, Steffen and Uhlig, G. and Rudorf, Wolf-Dieter},
  title     = {Study of the distribution of pi-Electrons in Push-Pull Alkenes by 1H an 13C NMR spectroscopy},
  year      = {1993},
  language  = {en}
}
@article{LehmannKleinpeter1993,
  author    = {Lehmann, J. and Kleinpeter, Erich},
  title     = {1H NMR Lanthanideinduced Shift (LIS) investigations of highly flexible molecules : a new approach ; Part II},
  year      = {1993},
  language  = {en}
}
@article{LehmannKleinpeter1993,
  author    = {Lehmann, J. and Kleinpeter, Erich},
  title     = {1H NMR Lanthanideinduced Shift (LIS) investigations of highly flexible molecules : a new approach},
  year      = {1993},
  language  = {en}
}
@article{StroehlKleinpeter1993,
  author    = {Str{\"o}hl, D. and Kleinpeter, Erich},
  title     = {Zur Stereochemie acyclischer Verbindungen : III. Bestimmung der Vorzugskonformstion unterschiedlich substituirternY-Chlorpropylether},
  year      = {1993},
  language  = {de}
}
@article{HaufeRolleKleinpeteretal.1993,
  author    = {Haufe, G. and Rolle, U. and Kleinpeter, Erich and Kivikoski, J. and Rissanen, K.},
  title     = {N-Heterocyclization in electrophilic haloamination reactions of 1,5-cyclooctadiene : formation of the granatanine and homotropane skeletons},
  year      = {1993},
  language  = {en}
}
@article{MaekiPihlajaKleinpeteretal.1994,
  author    = {M{\"a}ki, E. and Pihlaja, Kalevi and Kleinpeter, Erich and Hartmann, J{\"u}rgen and Schroth, W.},
  title     = {Electron impact ionization mass spectrometry of some 4,9-Dihetro-(X,X)-cyclodeca-1,6-dienes : mono- and dibenzo analogues},
  year      = {1994},
  language  = {en}
}
@article{DargatzKellnerKleinpeteretal.1994,
  author    = {Dargatz, M. and Kellner, K. and Kleinpeter, Erich and Pallas, M.},
  title     = {Quantitative Bestimmung geringer Phosphatmengen in Trinatriumphosphonoformiat mittels 31P-NMR-Spektroskopie},
  year      = {1994},
  language  = {de}
}
@article{KleinpeterHeydenreichChatterjeeetal.1994,
  author    = {Kleinpeter, Erich and Heydenreich, Matthias and Chatterjee, S. K. and Rudorf, Wolf-Dieter},
  title     = {Study of the pi-electron distribution in push-pull alkenes by 1H and 13C NMR spectroscopy},
  year      = {1994},
  language  = {en}
}
@article{KleinpeterHeydenreichChatterjeeetal.1994,
  author    = {Kleinpeter, Erich and Heydenreich, Matthias and Chatterjee, S. K. and Rudorf, Wolf-Dieter},
  title     = {Study of the pi-electron distribution in push-pull alkenes by 1H and 13C NMR spectroscopy, III : the conformation of 3,4-Dihydro-4-oxo-2H-thiins},
  year      = {1994},
  language  = {en}
}
@article{ScheerTroitzschHilfertetal.1995,
  author    = {Scheer, M. and Troitzsch, Ch. and Hilfert, Liane and Dargatz, M. and Kleinpeter, Erich and Jones, P. G. and Sieler, J.},
  title     = {PX-Liganden mit maximaler Elektronendonorf{\"a}higkeit, 7 : die Dreikomponenenreaktion von P4-Phosphor},
  year      = {1995},
  language  = {de}
}
@article{StarkeKochUhlemannetal.1995,
  author    = {Starke, Ines and Koch, Andreas and Uhlemann, Erhard and Kleinpeter, Erich},
  title     = {Nuclear-magnetic-resonance studies and molecular modelling of the solution structure of some dibenzo crown- ethers and their complexes},
  year      = {1995},
  language  = {en}
}
@article{StarkeKochHoldtetal.1995,
  author    = {Starke, Ines and Koch, Andreas and Holdt, Hans-J{\"u}rgen and Kleinpeter, Erich},
  title     = {1H, 13C, and 15N NMR study of the solution structure of metabridged bis(benzo-15-crown-5-ether)s},
  year      = {1995},
  language  = {en}
}
@article{OszczapowiczWawerDargatzetal.1995,
  author    = {Oszczapowicz, J. and Wawer, I. and Dargatz, M. and Kleinpeter, Erich},
  title     = {Amidines .34. N-15 NMR spectra of trisubstituted amidines - substituent effects},
  year      = {1995},
  language  = {en}
}
@article{KleinpeterKochHeydenreichetal.1995,
  author    = {Kleinpeter, Erich and Koch, Andreas and Heydenreich, Matthias and Chatterjee, S. K. and Rudorf, Wolf-Dieter},
  title     = {Study of the pi-electron distribution in push-pull alkenes by 1H and 13C NMR spectroscopy, IV : the conformation and dynamic behaviour of substituted N-Phenyl-2,3-dihydro-4(1H)-pyridones},
  year      = {1995},
  language  = {en}
}
@article{ThomasKleinpeter1995,
  author    = {Thomas, Steffen and Kleinpeter, Erich},
  title     = {Zur Zuordnung der 13C-Chemischen Verschiebungen substituierter Naphthaline aus Ladungsdichten mit Hilfe eines neuronalen Netzes},
  year      = {1995},
  language  = {de}
}
@article{LehmannKleinpeter1995,
  author    = {Lehmann, J. and Kleinpeter, Erich},
  title     = {1H NMR lanthanide-induced shift investigations of highly flexible molecules, part III. Applications to alcohols, aldehydes, esters and amines},
  year      = {1995},
  language  = {en}
}
@article{KochStarkeKleinpeter1995,
  author    = {Koch, Andreas and Starke, Ines and Kleinpeter, Erich},
  title     = {Conformational study of Dibenzo crown ethers and their complexation with Li+ and Na+},
  year      = {1995},
  language  = {en}
}
@article{KochKleinpeter1995,
  author    = {Koch, Andreas and Kleinpeter, Erich},
  title     = {Ab-initio study and semiempirical calculations of keto-enol tautomerism of triazolopyrimidines},
  year      = {1995},
  language  = {en}
}
@article{KleinpeterStroehlPeinze1995,
  author    = {Kleinpeter, Erich and Str{\"o}hl, D. and Peinze, S.},
  title     = {Solution conformation of tripeptides by NMR spectroscopy and force field calculations},
  year      = {1995},
  language  = {en}
}
@article{KleinpeterPihlaja1995,
  author    = {Kleinpeter, Erich and Pihlaja, Kalevi},
  title     = {Functions containing a thiocarbonyl group and at least one halogen, also at least one chalcogen and no halogen},
  year      = {1995},
  language  = {en}
}
@article{Kleinpeter1995,
  author    = {Kleinpeter, Erich},
  title     = {Effect of the variation of ring size of cyclic NR2 substituents on the barrier to rotation in amides, thioamides and related compounds},
  year      = {1995},
  language  = {en}
}
@article{Kleinpeter1995,
  author    = {Kleinpeter, Erich},
  title     = {Conformational analysis of six-membered sulfur-containing heterocycles},
  year      = {1995},
  language  = {en}
}
@article{KleinpeterThomasFischer1995,
  author    = {Kleinpeter, Erich and Thomas, Steffen and Fischer, G.},
  title     = {13C and 15N NMR study of 1,2,4-Triazolo[1,5-a]pyrimidines with one tautomerism-introducing substituent},
  year      = {1995},
  language  = {en}
}
@article{KleinpeterStarkeStroehletal.1996,
  author    = {Kleinpeter, Erich and Starke, Ines and Str{\"o}hl, D. and Holdt, Hans-J{\"u}rgen},
  title     = {NMR spectroscopic study of the solution structure and complexational behaviour of bis-benzocrown ethers},
  year      = {1996},
  language  = {en}
}
@article{KleinpeterStroehlPeinzeetal.1996,
  author    = {Kleinpeter, Erich and Str{\"o}hl, D. and Peinze, S. and Brandt, W. and Schmidt, R. and Neubert, K.},
  title     = {The solution conformation of cyclic ß-casomorphine-5 analogues},
  year      = {1996},
  language  = {en}
}
@article{PihlajaLehmannSchrothetal.1996,
  author    = {Pihlaja, Kalevi and Lehmann, S. and Schroth, W. and G{\"a}ber, M. and Kleinpeter, Erich},
  title     = {Electron impact induced fragmentation of dibenzo crown ethers},
  year      = {1996},
  language  = {en}
}
@article{Kleinpeter1996,
  author    = {Kleinpeter, Erich},
  title     = {The structure of hydantoins in solution and in the solid state},
  year      = {1996},
  language  = {en}
}
@article{Kleinpeter1996,
  author    = {Kleinpeter, Erich},
  title     = {NMR-Spektroskopie},
  year      = {1996},
  language  = {de}
}
@article{ThomasKleinpeter1996,
  author    = {Thomas, Steffen and Kleinpeter, Erich},
  title     = {Internet und World Wide Web : Nutzen f{\"u}r den NMR Spektroskopiker},
  year      = {1996},
  language  = {de}
}
@article{KleinpeterHeydenreichKalderetal.1997,
  author    = {Kleinpeter, Erich and Heydenreich, Matthias and Kalder, L. and Koch, Andreas and Henning, Dietrich and Kempter, Gerhard and Benassi, Rois and Taddei, F.},
  title     = {NMR spectroscopic and theoretical structural analysis of 5,5-disubstituted hydantoins in solution},
  year      = {1997},
  language  = {en}
}
@article{GrotjahnDrexlerJaegeretal.1997,
  author    = {Grotjahn, Manuela and Drexler, Hans-Joachim and J{\"a}ger, Norbert and Kleinpeter, Erich and Holdt, Hans-J{\"u}rgen},
  title     = {Molecular dynamic and conformational study of an unsaturated 12-crown-S202 ether and its AgI complexes},
  year      = {1997},
  language  = {en}
}
@article{KochKleinpeter1997,
  author    = {Koch, Andreas and Kleinpeter, Erich},
  title     = {Study of the tautomerism by experimentally and theoretically estimated 13C and 15N chemical shifts},
  year      = {1997},
  language  = {en}
}
@article{SarodnickHilfertKempteretal.1997,
  author    = {Sarodnick, Gerhard and Hilfert, Liane and Kempter, Gerhard and Kleinpeter, Erich},
  title     = {Reactin of 2-(halogenomethyl)-quinoxalines and quinolines with hydroxybenzoic acids and their esters},
  year      = {1997},
  language  = {en}
}
@article{ThomasBruehlHeilmannetal.1997,
  author    = {Thomas, Steffen and Br{\"u}hl, Iris and Heilmann, Dieter and Kleinpeter, Erich},
  title     = {13 C NMR Chemical shift calculations for some substituted pyridines - a comparative consideration},
  year      = {1997},
  language  = {en}
}
@article{HeydenreichKochKleinpeteretal.1997,
  author    = {Heydenreich, Matthias and Koch, Andreas and Kleinpeter, Erich and Zimmermann, Thomas},
  title     = {Dynamic NMR study of the flexibility of 2-amino-3-aroyl-4,6-diaryl-pyrylium salts},
  issn      = {0937-0633},
  doi       = {10.1007/s002160050205},
  year      = {1997},
  language  = {en}
}
@article{KochKleinpeter1997,
  author    = {Koch, Andreas and Kleinpeter, Erich},
  title     = {Restricted rotation about particial C, N Double Bond},
  year      = {1997},
  language  = {en}
}
@article{Kleinpeter1997,
  author    = {Kleinpeter, Erich},
  title     = {The Structure of hydantions in solution and in the solid state},
  year      = {1997},
  language  = {en}
}