Kathleen Hewson

Derivatives of 2,5-anhydroallitol and 2,5-anhydroaltritol

Abstract Two routes to protected derivatives of 2,5-anhydroallitol were investigated. The first route, involving a two-step reduction of 2,5-anhydro-6- O -benzoyl-3,4- O -isopropylidene- D -allonitrile (4) , gave a mixture of 2,5-anhydro-6- O -benzoyl-3,4- O -isopropylidene- D -altritol (7) and a lesser amount of the desired 2,5-anhydro-6- O -benzoyl-3,4- O -isopropylidene- D -allitol (6) . Isomerization was shown to occur in the first reduction step—treatment of the nitrile 4 with Raney nickel, sodium hypophosphite, and acetic acid. The second route gave isomerically pure 2,5-anhydro-3,4,6-tri- O -benzyl- D -allitol (21) via reduction of the corresponding ethyl allonate (18) .