Novel compounds represented by the formula: ##STR1## wherein R represents hydrogen, alkyl radicals having from 1 to about 10 carbon atoms, alkenyl radicals having from 1 to about 10 carbon atoms, aryl, alkaryl and aralkyl radicals having from about 6 to about 16 carbon atoms and acyl and acyloxy radicals having from about 1 to about 10 carbon atoms, manifest glycosidase inhibition activity.