Abstract: A compound of the formula ##STR1## wherein n, m, and p, which may be the same or different, are a number between 0 and 5; q is a number between 0 and 10; R.sub.1, R.sub.2 R.sub.3 R.sub.4 and R.sub.5, which may be the same or different, are a hydrogen, a hydroxyl, a halogen, a hydrocarbon or an O-hydrocarbon group having between 1 and 6 carbons which is aliphatic, alicyclic or aromatic, or a glycosyl group; and R.sub.4 is a glycosyl group, is disclosed. Nitrogen oxides of such compounds are also included. These novel compounds have been found to be potent glycohydrolase inhibitors. Processes for preparing these novel compounds and methods for their use in the treatment of diabetes mellitus are also provided.