An investigation of the transmission of electronic effects in a series of 5- and 6-substituted benzazoles by the methods of basic deuterium exchange and nmr spectroscopy
The kinetics of deuterium exchange at the methyl groups in 5- and 6-substituted 2-methylbenzothiazoles, 6-substituted 2-methylbenzoxazoles, and 5-substituted 1,2-dimethylbenzimidazoles have been studied. A quantitative estimate of the influence of the substituents on the free energy of activation of deuterium exchange and on the chemical shifts in the /sup 1/H, /sup 13/C, and /sup 19/F NMR spectra of the benzazoles investigated and of the substituted quinolines and napthalenes used as standard systems has been made with the aid of correlation analysis. It has been shown that the decrease in the transmission capacity of the benzazole nucleus in the transition state of the reaction as compared with the initial state is due to the influence of cross-conjugation effects disturbing the additive nature of the electronic interactions. The question of the probable structure of the transition state of the reaction is discussed.
- Research Organization:
- Institute of Applied Chemistry, Leningrad
- OSTI ID:
- 7169902
- Journal Information:
- Chem. Heterocycl. Compd. (Engl. Transl.); (United States), Journal Name: Chem. Heterocycl. Compd. (Engl. Transl.); (United States) Vol. 20:9; ISSN CHCCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
ACTIVATION ENERGY
AZOLES
CARBON 13
CARBON ISOTOPES
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL SHIFT
DEUTERIUM
DISPERSIONS
ELECTRON EXCHANGE
ELECTRON TRANSFER
ENERGY
EVEN-ODD NUCLEI
FLUORINE 19
FLUORINE ISOTOPES
HETEROCYCLIC COMPOUNDS
HYDROGEN 1
HYDROGEN ISOTOPES
IMIDAZOLES
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LIGHT NUCLEI
MIXTURES
NMR SPECTRA
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXAZOLES
REACTION KINETICS
SOLUTIONS
SPECTRA
STABLE ISOTOPES
TEMPERATURE EFFECTS
THIAZOLES
YIELDS