TY  - JOUR
A1  - Pihlaja, Kalevi
A1  - Sinkkonen, Jari
A1  - Stajer, Geza
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - 1-Oxo-1,3-dithiolanes - synthesis and stereochemistry
JF  - Magnetic resonance in chemistry
N2  - 1-Oxo-1,3-dithiolane (4) and its cis- and trans-2-methyl (5,6), -4-methyl (7,8) and -5-methyl (9,10) derivatives were prepared by oxidizing the corresponding 1,3-dithiolanes (1-3) with NaIO(4) in water. The oxides were purified and their isomers separated using thin layer chromatography. The structural characterization was carried out with (1)H and (13)C NMR spectroscopy and molecular modelling. The sulfoxides 4-6 and 8-10 attain two S(1) type envelopes (sometimes slightly distorted) the S=O(ax) envelope greatly dominating. Cis-4-methyl-1-oxo-1,3-dithiolane is a special case exhibiting both two closely related S=O(ax) (30 and 27%) as well as S=O(eq) (21 and 22%) forms [S(1) and C(4) envelopes, respectively]. The relative energies of these conformations, the values of (1)H-(1)H coupling constants and (1)H and (13)C chemical shifts were estimated by computational methods and they support well the conclusions based on the experimental data.
KW  - NMR
KW  - (1)H NMR
KW  - (13)C NMR
KW  - sulfur heterocycles
KW  - conformational analysis
KW  - computational chemistry
Y1  - 2011
U6  - https://doi.org/10.1002/mrc.2764
SN  - 0749-1581
VL  - 49
IS  - 7
SP  - 443
EP  - 449
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - GEN
A1  - Pihlaja, Kalevi
A1  - Kleinpeter, Erich
T1  - Professor Ferenc Fulop a tribute
T2  - Arkivoc : free online journal of organic chemistry
Y1  - 2012
SN  - 1551-7004
SP  - 1
EP  - 5
PB  - ARKAT
CY  - Gainesville
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Pihlaja, Kalevi
A1  - Sinkkonen, Jari
A1  - Stájer, Gezá
A1  - Koch, Andreas
T1  - 1-Oxo-1,3-dithiolanesùsynthesis and stereochemistry
N2  - 1-Oxo-1,3-dithiolane (4) and its cis- andtrans-2-methyl (5,6), -4-methyl (7,8) and -5-methyl (9,10) derivatives were prepared by oxidizing the corresponding 1,3-dithiolanes (1-3) with NaIO4 in water. The oxides were purified and their isomers separated using thin layer chromatography. The structural characterization was carried out with 1H and 13C NMR spectroscopy and molecular modelling. The sulfoxides 4-6 and 8-10 attain two S(1) type envelopes (sometimes slightly distorted) the S=Oax envelope greatly dominating. Cis-4-methyl-1-oxo-1,3-dithiolane is a special case exhibiting both two closely related S=Oax (30 and 27%) as well as S=Oeq (21 and 22%) forms [S(1) and C(4) envelopes, respectively]. The relative energies of these conformations, the values of 1H-1H coupling constants and 1H and 13C chemical shifts were estimated by computational methods and they support well the conclusions based on the experimental data.
Y1  - 2011
SN  - 0749-1581
ER  - 
TY  - JOUR
A1  - Mäki, E.
A1  - Pihlaja, Kalevi
A1  - Kleinpeter, Erich
A1  - Hartmann, Jürgen
A1  - Schroth, W.
T1  - Electron impact ionization mass spectrometry of some 4,9-Dihetro-(X,X)-cyclodeca-1,6-dienes : mono- and dibenzo analogues
Y1  - 1994
ER  - 
TY  - BOOK
A1  - Pihlaja, Kalevi
A1  - Kleinpeter, Erich
T1  - 13C NMR chemical shifts in structural and stereochemical analysis
T3  - Methods in stereochemical analysis
Y1  - 1994
PB  - VCH
CY  - New York
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Pihlaja, Kalevi
T1  - Functions containing a thiocarbonyl group and at least one halogen, also at least one chalcogen and no halogen
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Pihlaja, Kalevi
A1  - Lehmann, S.
A1  - Schroth, W.
A1  - Gäber, M.
A1  - Kleinpeter, Erich
T1  - Electron impact induced fragmentation of dibenzo crown ethers
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Heydenreich, Matthias
A1  - Woller, Jochen
A1  - Wolf, Gunter
A1  - Koch, Andreas
A1  - Kempter, Gerhard
A1  - Pihlaja, Kalevi
T1  - Configuration and stereodynamics of exo/endoisomeric push-pull alkenes of pentadiene structure
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Reiche, K. B.
A1  - Starke, Ines
A1  - Kleinpeter, Erich
A1  - Holdt, Hans-Jürgen
A1  - Pihlaja, Kalevi
A1  - Oksaman, P.
A1  - Ovcharenko, V. V.
T1  - Fragmentation of imine-type meta-bridged bis(benzo crown ether)s under electron impact
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Tahtinen, Petri
A1  - Bagno, Alessandro
A1  - Koch, Andreas
A1  - Pihlaja, Kalevi
T1  - Conformational analysis of saturated trans-fused 1,3,2-benzoxazaphosphinine 2-oxides - DFT calculation of NMR J(PH) coupling constants
N2  - The (3)J(P,H) and (4)J(P,H) spin-spin coupling constants of a selected test set of organophosphorus compounds, calculated by density functional theory (DFT) methods, were found to correlate well with the experimentally measured coupling constants. The contribution of the spin-dipole (SD) term to the coupling constants was found to be negligible, and the diamagnetic and paramagnetic spin-orbit (DSO and PSO) terms cancelled each other, as in the case of J(H,H). Calculation solely of the Fermi contact (FC) term was found to be sufficient to provide good estimates of the coupling constants. In the second part of the work, the conformational equilibria and coupling constants in 2-bis(2- chloroethyl)amino-trans-octahydro-2H-1,3,2-benzoxazaphosphinine 2-oxide and its 3-methyl derivative were studied. DFT methods failed in predicting the relative stabilities of the conformations but yielded good geometries and coupling constants. Optimization of the conformations at the Moller-Plesset second-order perturbation theory (MP2) level resulted in energy differences compatible with previous experimental observations. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Y1  - 2004
SN  - 1434-193X
ER  -