A new phthalidyl derivative of apovincaminic acid: (3 alpha,16 alpha)-eburnamenine-14 carboxylic acid phthalidyl ester (AF 698). A preliminary report on its chemical and pharmacological properties

A new phthalidyl derivative of apovincamine, (3 alpha,16 alpha)-eburnamenine-14 carboxylic acid phthalidyl ester (AF 698), has been synthesized as hydrochloride. Its chemical and physical properties are described and its acute toxicity and vasodilator effect assayed in comparison with vincamine hydrochloride. AF 698 proved to possess lower acute toxicity than vincamine. Its peripheral vasodilator action, assayed on the perfused rat lower limb, was higher than that of vincamine. AF 698 was also more effective than vincamine in its central vasodilator activity electrocorticographically evaluated on the response of rabbits to selective cerebral ischaemia. The protective effect against the lethal action of hypobaric hypoxia in mice did not greatly differ between the two drugs.