The Analysis of Fructoside Mixtures by Means of Invertase. VI. Methylated and Acetylated Derivatives of Crystalline β-Benzylfructopyranoside¹

SYNTHESIS OF d-FRUCTOPYRANOSE 2-PHOSPHATE AND d-FRUCTOFURANOSE 2-PHOSPHATE

“…Hudson & Brauns (1916). Purves & Hudson (1937b). either Dowex 50 (pyridinium form) or Dowex 50 (H+ form) followed by neutralization with pyridine.…”

Chemistry of the Carbohydrates and Glycosides

“…This fact is not surprising since :aldoses and ketoses differ in respect to the carbon atoms which are responsible for the a-and �-modifications and which form the ring isomers. Purves & Hudson (74) found that �-methyl-and �-benzyr-d-fructopyranosides are hy drolyzed by hydrochloric acid at a rate comparable with that of su crose, a fructofuranoside, and pointed out that glycosides of the keto sugar, fructose, differ from those of the aldoses in that the furanoid and pyranoid ring types of fructose possess nearly the same stability toward acid hydrolysis. In this connection, it is of interest to note that the aldoses and aldonic acids also differ on the first carbon and that at equilibrium the six-membered pyranoid ring predominates, whereas the five-membered lactone ring predominates in the sugar acids.…”

The proton affinities and deprotonation enthalpies of β-D-fructopyranose and α-L-sorbopyranose

“…That this cyclic oxocarbenium ion was found in the present study for 1 and not for 2 may be of relevance as regards both the rates of mutarotation of 1 and 2 and the rates of acid-catalyzed hydrolysis of the corresponding glycosides. It is well known that 1 exhibits rapid mutarotation while 2 does not (27), and that methyl P-D-fructopyranoside is hydrolyzed at a significantly faster rate than is methyl a-L-sorbopyranoside (28,29). The implications of these calculations, as concerns the mechanisms of mutarotation of ketopyranoses and of ketopyranoside hydrolysis, will be the subject of a future study.…”