Conformational characteristics of 5-halogenotetrahydro-1,3-thiazine-2-thiones
A characteristic feature of monosubstituted cyclohexanes is the predominance of the equatorial form in the conformational equilibrium. This classical rule is violated in the case of 4-substituted cyclohexanones and certain other six-membered cyclic systems with electronegative substituents. The axial conformer in such compounds is more stable than the equatorial conformer, and this has been explained by intramolecular electrostatic and orbital interactions. The authors have discovered a similar effect during a PMR investigation (250 MHz, solutions in DMSO-d/sub 6/) of 5-chloro- and 5-bromotetrahydro-1,3-thiazine-2-thiones. The position of the chair-chair conformational equilibrium for these compounds can be determined by means of the averaged width of the signal (w = ..sigma..J/sub HH/) for the H/sub x/ proton. The H/sub x/ signal represents a well resolved symmetrical septet with a width of 17.0 +/- 0.5 Hz (delta 4.92 ppm) for the chlorine-substituted compound and 19.0 +/- 0.5 Hz (delta 4.95 ppm) for the bromine-substituted compound, measured between the terminal peaks.
- Research Organization:
- M. V. Lomonosov Moscow State Univ. (USSR)
- OSTI ID:
- 6974730
- Journal Information:
- J. Org. Chem. USSR (Engl. Transl.); (United States), Journal Name: J. Org. Chem. USSR (Engl. Transl.); (United States) Vol. 23:4; ISSN JOCYA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
640302 -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
AZINES
CHEMICAL SHIFT
CONFIGURATION INTERACTION
CONFORMATIONAL CHANGES
COUPLING
COUPLING CONSTANTS
DEUTERIUM COMPOUNDS
DIPOLE MOMENTS
DMSO
ELECTRONIC STRUCTURE
ELECTROSTATICS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
INTERMEDIATE COUPLING
J-J COUPLING
LINE WIDTHS
MAGNETIC DIPOLE MOMENTS
MAGNETIC MOMENTS
MOLECULAR STRUCTURE
MULTIPLETS
NMR SPECTRA
ORGANIC BROMINE COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
SPECTRA
STRUCTURAL CHEMICAL ANALYSIS
SULFOXIDES