Inhibitors of glucosidases with related structures and inverse specificity

A dinitrophenyl ether (III) of gluconolactone oxime I was synthesized and tested as an inhibitor of glucosidases. Surprisingly, in contrast to the known compound II, III was found to be a modest inhibitor of beta-glucosidase, but a good inhibitor of alpha-glucosidase (Ki = 5 μM).