PURPOSE: To efficiently obtain the subject new compound usable as a raw material for anti-hypertensive agents by oxidizing and then reducing the unsaturated lactone ring of digitoxigenin-3-acetate with a periodate in the presence of ruthenium tetroxide followed by hydrolyzing and then oxidizing the resulting product.

CONSTITUTION: First, the α,β-unsaturated lactone ring of digitoxigenin-3-acetate of formula I (Ac is acetyl) is oxidized with an alkali metal periodate in the presence of a catalytic amount of ruthenium tetroxide to form a keto derivative of formula II [R is H, COCHO, COCH(OH)2 or COCOOH]. Secondly, the keto derivative is reduced with sodium borohydride followed by hydrolyzing the 3- and 21-sites of the ester group to form the corresponding tetrol of formula III. Subsequently, the tetrol is oxidized with an alkali metal periodate to efficiently obtain the objective 3β-14β-dihydroxyethianaldehyde of formula IV useful as an intermediate for producing anti-hypertensive agents.