3-Oxo-12β, 14-dihydroxy-14β-carda-4, 20(22)-dienolide (VII) derivable from digoxigenin (V) was treated with lithium borohydride in pyridine to give 5α-digoxigenin (VIa), which was demonstrated to be identical with the natural cardenolide aglycone, syriogenin. The structure of syriogenin was thus firmly established as 3β, 12β, 14-trihydroxy-5α, 14β-card-20(22)-enolide.
