Efficient carbon-Ferrier rearrangement on glycals mediated by ceric ammonium nitrate: Application to the synthesis of 2-deoxy-2-amino-C-glycoside.

A carbon-Ferrier rearrangement on glycals has been performed by using ceric ammonium nitrate to obtain products in moderate to good yields with high selectivity. The versatility of this method has been demonstrated by applying it to differently protected glycals and by employing several nucleophiles. The obtained C-allyl glycoside has been utilized for the synthesis of a orthogonally protected 2-amino-2-deoxy-C-glycoside.

Bicyclic hybrid sugars as glycosidase inhibitors: synthesis and comparative study of inhibitory activities of fused oxa-oxa, oxa-aza, and oxa-carbasugar hybrid molecules.

A few bicyclic hybrid sugar molecules comprising of oxa-aza, oxa-oxa, and oxa-carbasugar fused skeletons were designed and synthesized from C-2 acetoxyglucal involving Ferrier rearrangement, Grignard addition, and ring-closing metathesis as key steps. The inhibitory activities of the synthesized molecules were tested against commercially available enzymes, which revealed the sugar-piperidine and sugar-pyran hybrids as potent and selective inhibitors.

Synthesis of dihydroxymethyl dihydroxypyrrolidines and steviamine analogues from C-2 formyl glycals.

Synthesis of dihydroxymethyl dihydroxypyrrolidines from C-2 formyl D-glycals has been described via a common dicarbonyl intermediate. The hence obtained pyrrolidines have been further utilized for the synthesis of some steviamine analogues. The newly synthesized molecules have been evaluated for glycosidase inhibition against 6 commercially available enzymes and found to be active in the micromolar range, where one of the steviamine analogues showed good and selective inhibition of ß-mannosidase (Helix pomatia).

Recent developments in design and synthesis of bicyclic azasugars, carbasugars and related molecules as glycosidase inhibitors.

The importance of glycosidase inhibitors and especially the bicyclic molecules has led to design and assessment of many analogs of naturally occurring molecules. This review focuses on the synthesis and enzyme inhibitions of a few selected (synthetic or non-naturally occurring) molecules that have been reported in the last decade, which allow one to draw some connection between varying the structural features and their effect on glycosidase inhibitions. It is expected that further improvements based on these features could lead to improved inhibitors.

Ceric ammonium nitrate-catalyzed azidation of 1,2-anhydro sugars: application in the synthesis of structurally diverse sugar-derived morpholine 1,2,3-triazoles and 1,4-oxazin-2-ones.

Azidation of 1,2-anhydro sugars with NaN(3) in CH(3)CN by using a catalytic amount of ceric ammonium nitrate has been accomplished in a regio- and stereoselective manner. Various 1,2-anhydro sugars produced 2-hydroxy-1-azido sugars in good yields which, in turn, were converted to structurally diverse sugar-derived morpholine triazoles and sugar oxazin-2-ones. These sugar derivatives were tested against various commercially available glycosidases, and two of them were found to be active in the micromolar range.