Carbon-13 NMR studies of [1-13C]aldoses: empirical rules correlating pyranose ring configuration and conformation with carbon-13 chemical shifts and carbon-13/carbon-13 spin couplings
Effects of Alkali-Metal Ions and Counter Ions in Sn-Beta-Catalyzed Carbohydrate Conversion
作者:Samuel G. Elliot、Søren Tolborg、Robert Madsen、Esben Taarning、Sebastian Meier
DOI:10.1002/cssc.201702413
日期:2018.4.9
presence of alkali‐metalions has a differential effect in competing reaction pathways and promotes the rate of carbon–carbon bond breakage of carbohydrate substrates, but decreases the rates of competing dehydration pathways. Further addition of alkali‐metalions inhibits the activity of Sn‐Beta in all major reaction pathways. The alkali‐metal effects on product distribution and on the rate of product
NMR Spectroscopic Isotope Tracking Reveals Cascade Steps in Carbohydrate Conversion by Tin-Beta
作者:Samuel G. Elliot、Esben Taarning、Robert Madsen、Sebastian Meier
DOI:10.1002/cctc.201701861
日期:2018.3.21
were used to investigate the reaction pathways that occur for Sn‐Beta‐catalyzed carbohydrate conversion to various α‐hydroxy esters. Experimental insight into the conversion of pentoses was sought (i) by identifying pathways based on isotope patterns in the reaction products and (ii) by probing asymmetric isotope incorporation into products. The results indicate that reaction intermediates remain coordinated
Phosphate-Catalyzed Degradation of <scp>d</scp>-Glucosone in Aqueous Solution Is Accompanied by C1–C2 Transposition
作者:Wenhui Zhang、Anthony S. Serianni
DOI:10.1021/ja3020296
日期:2012.7.18
instead initially undergoes C1-C2 bondcleavage to yield d-ribulose 3 and formate. The latter bondcleavage occurs via a 1,3-dicarbonyl intermediate initially produced by enolization at C3 of 2. However, a careful monitoring of the fates of the sketetal carbons of 2 during its conversion to 3 revealed unexpectedly that C1-C2 bondcleavage is accompanied by C1-C2 transposition in about 1 out of every
(1-13C)Alditols: elimination of magnetic equivalence in 1H-and 13C-n.m.r. spectra of symmetric compounds through (13C)-substitution
作者:Eugenia C. Garrett、Anthony S. Serianni
DOI:10.1016/0008-6215(90)80082-e
日期:1990.12
(1-13C)Glycerol, D-(1-13C)arabinitol, D-(1-13C)ribitol, D-(1-13C)xylitol, D-(1-13C)glucitol, D-(1-13C)mannitol, and D-(1-13C)talitol have been prepared by NaBH4 reduction of the corresponding (1-13C)aldoses. A comparison of the 1H- (300 and 620 MHz) and 13C (75 MHz) n.m.r. spectra of natural and (1-13C)-substituted dissymmetric alditols has permitted the unequivocal assignments of their hydroxymethyl
Carbon-13 NMR studies of [1-13C]aldoses: empirical rules correlating pyranose ring configuration and conformation with carbon-13 chemical shifts and carbon-13/carbon-13 spin couplings