Abstract
Because several series of compounds having amidine moieties that had been synthesized had a marked effect on influenza viruses in mice, iminoesterification by the reaction of amides with triethyloxonium fluoroborate was examined and cyclic amidines were obtained by the reaction of a lactam with triethyloxonium fluoroborate, followed by ammonolysis of resulting ethyl imidate with ammonia. Thus, five kinds of cyclic amidines and two compounds of cyclic amidines having a carboxamide moiety were obtained by this method. On the other hand, the reaction of 3-benzoylaminopropionamide with triethyloxonium fluoroborate afforded a cyclized compound, 2-phenyl-5, 6-dihydro-4 (3H)-pyrimidinone, identical with an authentic sample prepared by the method of Kametani. Thus four compounds of 2-substituted 5, 6-dihydro-4 (3H)-pyrimidinone were synthesized, but, 3-substituted benzoylaminopropionamide having a negative group on the phenyl ring did not afford any cyclized compound, but did 3-benzoylaminopropionimidate. It was considered from these results that ethylation of oxygen atom in the benzamide moiety might be essential for this cyclization.
