Polycyclic N-heterocyclic compounds. Part 621: Reaction of N-(quinazolin-4-yl)amidine derivatives with hydroxylamine hydrochloride and anti-platelet aggregation activity of the products

The reactions of N-(5,6,7,8-tetrahydroquinazolin-4-yl)amidines and their amide oximes with hydroxylamine hydrochloride gave abnormal cyclization products via a ring cleavage of pyrimidine component accompanied with a ring closure of 1,2,4-oxadiazole to give N-[2-([1,2,4]oxadiazol-5-yl)cyclohexen-1-yl]formamide oximes. Similarly, N-(quinazolin-4-yl)amidines reacted with hydroxylamine hydrochloride gave the same results. The evaluation of inhibitory activities against platelet aggregation in vitro is also described to show one derivative has potent activity.