Conformational studies of N(3)-substituted [1,3,4]-oxadiazinan-2-ones.
Pseudoephedrine-based [1,3,4]-oxadiazinan-2-ones acylated at the N(3)-position with either acetyl (2a), propionyl (2b), or phenylacetyl (2c) substituents are known to undergo conformational changes that are observable by (13)C NMR spectroscopy. The conformational properties of new [1,3,4]-oxadiazinan-2-one derivatives 2d-k are examined by X-ray crystallography and variable-temperature (13)C NMR spectroscopy and further evaluated by semiempirical AM1 calculations. The collected data reveal that the conformational changes of the overall ring system are dependent upon the stereoelectronic factors of the N(3)-substituent.
Casper
David M
DM
Department of Chemistry, Illinois State University, Normal 61790-4160, USA.
Blackburn
Jennifer R
JR
Maroules
Christopher D
CD
Brady
Tana
T
Esken
Joel M
JM
Ferrence
Gregory M
GM
Standard
Jean M
JM
Hitchcock
Shawn R
SR