ANNULATED PYRANSIDES FOR OPTICALLY ACTIVE POLYQUINANES

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Actinobolin and bactinobolin are congeners that are closely structurally related. However, their biological activities are most dissimilar. Actinobolin was for several years widely investigated, but its prospects as an antibiotic were not encouraging. However, much interest currently centers around its use for oral hygiene in preventing the formation of dental caries. Bactinobolin, on the other hand, is a promising antitumor agent, being up to one-thousand times more potent than actinobolin. Our synthetic plan is to prepare actinobolin in optically active form from a carbohydrate precursor. We intend to take advantage of our observation that in "annulated pyranosides", the anomeric effect operating in the pyranoside moiety, controls the conformation of the entire assembly. Thus stereocontrolled transformations can be carried out on the "annulus". Allied studies will be undertaken to help amplify and clarify qualitative and quantitative aspects of the anomeric effect. These will extend to theoretical studies to be undertaken jointly with Professor Dennis Liotta. Actinobolin is to be synthesized first and minor changes at late stages of the synthetic plan will enable us to achieve bactinobolin. Relay studies from actinobolin itself will influence our synthetic design.