β-Acarbose. V. The Synthesis of a Hydroxylated Derivative of a Diastereoisomer of Methyl Acarviosin

The treatment of a 1-epivalienamine derivative with 1,6:3,4-dianhydro-2-O-benzyl-β-D-galactose has given an amino alcohol capable of conversion into either a cyclic carbamate or an aziridine. All attempts at acetolysis of the 1,6-anhydro ring of the cyclic carbamate failed owing to the inherent reactivity of the (allylic) benzyl ethers present in the molecule. Therefore, following a reduction with lithium in ammonia and acetylation of the product, a new cyclic carbamate was obtained which underwent successful acetolysis to provide a heptaacetate. This heptaacetate could be transformed into the desired methyl β-D-glucoside and base hydrolysis provided the 6-hydroxylated derivative of a diastereoisomer of methyl acarviosin, a putative inhibitor of enzymes which process β-D-glucosidic linkages.