Thiocardenolides I: Synthesis and Biological Actions of 3β-Thiocyanato-14β-Hydroxy-5β-card-20(22) -enolide

The synthesis of a 3β‐thiocyanatocardenolide is described. The compound exhibited about 0.1 times the cardiotonic effect of digitoxigenin in the isolated frog heart preparation. At a dosage of 20 mg/kg in the intact rat, it elicited ECG changes similar to those seen with a 10‐mg/kg dose of digitoxigenin. Studies also revealed the new cardenolide to be a reversible inhibitor of sodium‐ and potassium‐activated adenosine triphosphatase.