h) As an alternative, 10 g (0.00 mole) XV, I 0 g (0.12 iiiole) IStMgHr,, and 100 in1 Bt,O is treated at 0" with bromide dissolved in H,O, NaHC'O, ailcletl, tlic mixture filtered, and thc ethcr h y e r separated. '1s evaporation of the rthereal solution giveis only 0.3 g X X , the aqueous layer is ev
Equilibres conformationnels de glucides au niveau de liaisons σ sp2-sp3 C-C. III Dérivés d'oximes d'aldéhydo-sucres utilisation de tris-dipivaloylméthanato-europium
✍ Scribed by J. M. J. Tronchet; F. Barbalat-Rey; N. Le-Hong
- Publisher
- John Wiley and Sons
- Year
- 1971
- Tongue
- German
- Weight
- 769 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0018-019X
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
A series of sugar oximes and O‐methyloximes of the general formula RCHNOR′ (R′ H, CH~3~) have been studied by PMR. spectroscopy. These compounds exist in solution as a mixture of the syn and anti isomers. The conformational equilibrium of the syn isomers seems to consist exclusively of the eclipsed rotamers, whereas for the anti isomers there appears to be a significant contribution from bisecting rotamers. Using tris‐dipivaloylmethanato‐europium it is found that the α proton of the anti oximes is much more deshielded than the corresponding proton of the syn isomers, which means that the downfield shift of a particular proton does not depend exclusively on its distance from the oxygen of the oxyimino group.
📜 SIMILAR VOLUMES
## Abstract The conformation of 34 branched‐chain unsaturated sugars, prepared by reacting different __Wittig__ reagents with a series of 1,2‐O‐isopropylidene‐furannosul‐3‐oses, has been studied by PMR spectroscopy. The position of each compound in the flexible conformational cycle has been establi