TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Tolstikova, Ljudmila L.
A1  - Schilde, Uwe
T1  - Simple methods for the preparation of N-triflyl guanidines and the structure of compounds with the CF3SO2N=C-N fragment
JF  - Journal of fluorine chemistry
N2  - Two novel and simple approaches to N-triflyl guanidines are elaborated. Owing to very strong conjugation the formally double C=N bond of TIN=C(NHR)(2) is longer than the formally single N-C bonds. Energetic effect of the triflylgroup on the conjugation in the N-C=N moiety is estimated to be >= 150 kcal/mol.
KW  - N-triflyl guanidines
KW  - Synthesis
KW  - Structure
KW  - X-ray
KW  - MP2 calculations
Y1  - 2012
U6  - https://doi.org/10.1016/j.fluchem.2011.12.004
SN  - 0022-1139
VL  - 135
IS  - 1
SP  - 261
EP  - 264
PB  - Elsevier
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Ushakov, Igor A.
A1  - Tolstikova, Ljudmila L.
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - N-Trifyl substituted 1,4-diheterocyclohexanesùstereodynamics and the Perlin effect
N2  - The stereodynamic behaviour of 1-(trifluoromethylsulfonyl)piperidine 1, 4-(trifluoromethylsulfonyl)morpholine 2, 1,4-bis(trifluoromethylsulfonyl)piperazine 3 and 4-(trifluoromethylsulfonyl)thiomorpholine 1,1-dioxide 4 was studied by low-temperature 1H, 13C and 19F NMR spectroscopies. In acetone solution, compounds 1, 2 and 4 were found to exist as mixtures of two conformers in the ratio of 4:1, 4:1 and 8:1, respectively, differing by orientation of the CF3 group with respect to the ring. Compound 3 exists as a mixture of three conformers in the ratio of 3:28:69 also differing by the orientation of the two CF3 groups. Unlike the previously studied N-trifyl substituted 1,3,5-triheterocyclohexanes, the preferred conformers of compound 1 and of 1,4-diheterocyclohexanes 2-4 are those with the CF3 group directed outward from the ring, which is caused by intramolecular interactions of the oxygen atoms of the CF3SO2N groups with the equatorial hydrogens in the ;-position. B3LYP/6-311+G(d,p) calculations of the energy, geometry and NMR parameters corroborate the experimental data. The calculated Perlin effects for all conformers of compounds 1-4 as well as those measured for the major conformers of compounds 3 and 4 were analyzed by the use of the NBO analysis.
Y1  - 2008
ER  -