Chemistry and Pharmacology of 16-Acetyl Digitalinum Verum

Abstract

THE 16-acetyl derivative of digitalinum has been prefaced as follows. Digitalinum verum hexaacetate was obtained by the usual reaction of digitalinum verum with acetic anhydride in pyridine solution; this hexaacetate, using snail enzyme¹, was partially deacetylated by potassium hydrogen carbonate to digitalinum verum diacetate, m.p. 181°–184°, (α)_D–24.0° (CH₃OH). The substance was separated by partition chromatography from the reaction mixtures, but it could not be induced to crystallize. The existence of acetoxyl group on carbon atom 16 of this glycoside has been confirmed by the facts that on treatment with alumina it affords a hydrogenated derivative, and that the molecular rotation difference between digitalinum verum and this compound is similar to the difference between gitoxigenin and oleandrigenin. Evidence is also given by the fact that it is hydrolysed into oleandrigenin on Mannich hydrolysis at low temperature (0°–5°).