Trifluoroacetic anhydride. A convenient NMR solvent for carbohydrates. 270 MHz ¹H NMR studies of 2‐acetamido‐2‐deoxyhexoses

Abstract

The use of trifluoroacetic anhydride as an NMR solvent for sugars has been explored. Dissolution of carbohydrates in this solvent is accompanied by trifluoroacetylation at the hydroxyl groups. Esterification results in downfield shifts of the sugar protons yielding very well resolved 'H NMR spectra. The use of trifluoroacetic anhydride in the analysis of complex systems is exemplified.

Ionic Liquids as Tools for the Acid‐Catalyzed Hydrolysis/Dehydration of Saccharides to Furanic Aldehydes

“…Chun et al reported 58 wt. [107] Xylose The reaction of xylose in H 2 SO 4 / [bmim]Cl with toluene as immiscible co-solvent (allowing in situ extraction of Fur) gave 44 % Y Fur (83 % C) at 100 8C/4 h (9 mol % H 2 SO 4 ; 5.3 wt. %) at 120 8C/1.5 h, using 0.3 m HCl in [omim]Cl (IL purity 98 %); [86] and 30 wt.…”

“…[90] In the latter case, the trifluoroacetylation of the hydroxyl groups of the saccharide units cannot be ruled out. [107] Xylose The reaction of xylose in H 2 SO 4 /[bmim]Cl with toluene as immiscible co-solvent (allowing in situ extraction of Fur) gave 44 % Y Fur (83 % C) at 100 8C/4 h (9 mol % H 2 SO 4 ; 5.3 wt. % xylose; IL purity !…”