Looking glass inhibitors: scalable syntheses of DNJ, DMDP, and (3R)-3-hydroxy-L-bulgecinine from D-glucuronolactone and of L-DNJ, L-DMDP, and (3S)-3-hydroxy-D-bulgecinine from L-glucuronolactone. DMDP inhibits β-glucosidases and β-galactosidases whereas L-DMDP is a potent and specific inhibitor of α-glucosidases

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-alpha-D-glucofuranose as a key intermediate in an overall yield of up to 72%; the same intermediate can be transformed into DMDP (2R,3R,4R,5R)-2,5-bis(hydroxymethyl)pyrrolidine-3,4-diol] and (3R)-3-hydroxy-L-bulgecinine [(2S,3R,4R,5R)-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 (3S)-3-hydroxy-D-bulgecinine. A comparison of glycosidase inhibition by DMDP (an inhibitor of beta-glucosidases and beta-galactosidases) and L-DMDP (a potent and specific alpha-glucosidase inhibitor) with the corresponding enantiomeric hydroxybulgecinines is reported; DMDP and (3R)-3-hydroxy-L-bulgecinine show weak inhibition of glycogen phosphorylase. (C) 2010 Elsevier Ltd. All rights reserved.