A new approach to Amadori ketoses via MoVI-catalyzed stereospecific isomerization of 2-C-branched sugars bearing azido function in a microwave field

A branched-chain aldose bearing an azido group at the C-2 position provides access to the corresponding 1-deoxy-1-azido- and 1-deoxy-1-amino ketoses in a single step via stereospecific isomerization. The isomerization exploited the catalytic effect of molybdate ions and microwave irradiation. The structures of the products were analyzed by NMR spectroscopy, IR, HRMS spectrometry and quantum-chemical DFT calculations. DFT-computed proton-proton coupling constants of the prepared Amadori ketose 1-deoxy1-amino-D-gluco-heptulose were found to be comparable with the experimentally obtained coupling constants and were in agreement with the C-4(1) pyranose form in aqueous solution at room temperature. (C) 2010 Elsevier Ltd. All rights reserved.