Spirohydantoins from D-ribose as new potent enzymatic inhibitors

Anomeric spirohydantoin derivatives from monosaccharides are known for vari ous biological properties. We describe herein the synthesis of the 3-spiroh ydantoin derivatives of D-allose and D-ribose. The key step is the stereose lective glyco-alpha -aminonitrile formation from ulose derivatives of D-glu cose and D-xylose using titanium tetra-isopropoxide as a mild and efficient catalyst. Target compounds were synthesized from these intermediates. The glucidic moiety was partially or totally deprotected under acidic condition s. These new heterocyclic monosaccharidic derivatives are potent glycogen p hosphorylase inhibitors.