A novel series of 4'-dehydroxyphlorizin derivatives was synthesized and the effects of these compounds on urinary glucose excretion were evaluated in rats. There was a strict structural requirement for activity. Introduction of a small substituent or a flat ring at the 3-and/or the 4- position on the A ring was permissible, but any change at the bridge part between the A and B rings or in the sugar moiety resulted in complete loss of activity. The 6'-OH group on the ...