Structure of methyl thienyl ketone oxime studied by the paramagnetic-additive method
The authors examine the E-Z isomerism of methyl thienyl ketone oxime (I), the initial product in the synthesis of 2-(2-thienyl)pyrrole, where they used PMR spectra transformed by shifting reagents. Lanthanide shifting reagents LSR can be used to advantage in solving such problems. The PMR spectrum of oxime I has the protons in the CH3 group responsible for two signals (sigma = 2.33 and 2.28 ppm), integral intensity ratio 1:3. The protons in the heterocyclic part also give two signals each. The addition of Eu(fod)3 to a solution containing a mixture of the two isomers of oxime I shifts the signals only for one isomer (the less intense), so the second isomer is not coordinated with the LSR under these conditions. They therefore examined the spectra of two specimens, in one of which there was 100% of the isomer having the strong-field signal and the other 95% of the isomer giving the weak-field one. In the absence of the other isomer, the strong-field one also coordinates with the LSR, as is evident from the PMR spectra, which also shows the observed paramagnetic shifts delta in Hz. The values of delta were derived with the oxime in substantial excess relative to the LSR. The signals from protons H-3 and H-5 overlap in the PMR spectra of specimens without added Eu(fod)3, so the assignment in the spectra of specimens containing LSR is of major importance. These signals have been assigned with allowance for the spin-spin interaction constants J for the protons in thiophenes.
- Research Organization:
- Irkutsk Institute of Organic Chemistry, Siberia, USSR
- OSTI ID:
- 6369816
- Journal Information:
- J. Struct. Chem. (Engl. Transl.); (United States), Journal Name: J. Struct. Chem. (Engl. Transl.); (United States) Vol. 27:2; ISSN JSTCA
- Country of Publication:
- United States
- Language:
- English
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Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ACTIVATION ENERGY
AMINES
CARBON TETRACHLORIDE
CHEMICAL SHIFT
CHLORINATED ALIPHATIC HYDROCARBONS
CHLOROFORM
COMPLEXES
CONFIGURATION INTERACTION
COUPLING
COUPLING CONSTANTS
ELECTRONIC STRUCTURE
ENERGY
EUROPIUM COMPLEXES
HALOGENATED ALIPHATIC HYDROCARBONS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INTERMEDIATE COUPLING
ISOMERS
J-J COUPLING
KETONES
LIGANDS
MOLECULAR STRUCTURE
NMR SPECTRA
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIMES
POLYCYCLIC SULFUR HETEROCYCLES
RARE EARTH COMPLEXES
SPECTRA
STRUCTURAL CHEMICAL ANALYSIS