Glucuronolactone

Abstract: A convenient large-scale synthesis of 1-deoxynojirimyin (DNJ) from d -glucuronolactone involves introduction of azide at C-5 with retention of configuration to give 5-azido-5-deoxy-1,2- O -isopropylidene-α- d -glucofuranose as a key intermediate in an overall yield of up to 72%; the same intermediate can be transformed into DMDP [(2 R, 3 R, 4 R, 5 R )-2,5-bis(hydroxymethyl)pyrrolidine-3,4-diol] and (3 R )-3-hydroxy- l -bulgecinine [(2 S, 3 R, 4 R, 5 R )-3,4-dihydroxy-5-hydroxymethyl- l -proline]. l -Glucuronolactone, a readily available l -sugar chiron, may similarly be used to access the enantiomers l -DNJ, l -DMDP, and (3 S )-3-hydroxy- d -bulgecinine. A comparison of glycosidase inhibition by DMDP (an inhibitor of β-glucosidases and β-galactosidases) and l -DMDP (a potent and specific α-glucosidase inhibitor) with the corresponding enantiomeric hydroxybulgecinines is reported; DMDP and (3 R )-3-hydroxy- l -bulgecinine show weak inhibition of glycogen phosphorylase.

Abstract: D-Glucose-1-C14, D-glucose-6-C14, D-mannose-1-C14, D-galactose-1-C14, D-glucuronolactone-1-C14, D-glucuronolactone-6-C14, potassium D-gluconate-6-C14, and L-arabinose-1-C14 were administered to wheat shoots. The cellulose and xylan were isolated after a 5 hour period of metabolism. Glucose was more readily converted to cellulose and xylan than any of the other compounds tested. The distribution of C14 in the glucose and xylose isolated from the polysaccharides indicates that xylan was formed from the aldohexoses and glucuronolactone by processes involving loss of carbon-6. L-Arabinose, unlike D-xylose and D-ribose, was converted to xylan with little rearrangement of the pentose skeleton.