An effective technique for one-stage synthesis of new polycyclic nitrogen-containing compounds has been developed. The procedure involves refluxing mixtures of camphoric acid with aliphatic or aromatic diamine without catalysts. In cases where the starting amine has a low boiling point (less than 200 °C), phenol is used as a solvent, as it is the most optimal one for obtaining products with good yields. It has been shown that the use of Lewis acids as catalysts reduces the yield of the reaction products. A set of compounds have been synthesized, which can be attributed to synthetic analogues of alkaloids. In vitro screening for activity influenza virus A was carried out for the obtained compounds. The synthesized quinazoline-like agent 14 has inhibitory activity against different strains of influenza viruses.