ISSN:
0030-4921
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Proton spin-spin coupling values measured for a wide range of tetrasubstituted tetrahydropyran ring-systems obtained from aldopentopyranose sugars have been correlated with values calculated from a generalized version of the Karplus equation which takes into account the electronegativities of the various atoms in the molecule and the configurations of these substituents. Minor discrepancies between observed and calculated values can be attributed to slight flattening of the tetrahydropyran ring as a result of steric interactions of the substituents. The magnitude of the geminal coupling J5e,5a of these aldopentopyranose derivatives provides a rough measure of the conformational population; when H-4 is axial [Cl(D) or 1C(L) conformation] J5e,5a is ∼10.9 Hz, and is ∼13.4 Hz when H-4 is equatorial [1C(D) or Cl(L) conformation].
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1270030405