title: Conformational studies of N(3)-substituted [1,3,4]-oxadiazinan-2-ones.
abstract: 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.
authors.affiliation: Department of Chemistry, Illinois State University, Normal 61790-4160, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Casper
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Blackburn
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Maroules
authors.forename: Tana
authors.initials: T
authors.lastname: Brady
authors.forename: Joel M
authors.initials: JM
authors.lastname: Esken
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Ferrence
authors.forename: Jean M
authors.initials: JM
authors.lastname: Standard
authors.forename: Shawn R
authors.initials: SR
authors.lastname: Hitchcock