Synthesis of Oxaazaisowurtzitane Derivatives Via Condensation of p-Toluenesulfonamide With Glyoxal

This work presents the study results on the acid-catalyzed cascade condensation of p-toluenesulfonamide with glyoxal in H₂SO₄ in order to synthesize aza- and oxaazaisowurtzitanes—a platform for promising high-energy-density compounds—and explore their formation processes. The effects of the ratio of starting reactants, acidity, reaction medium concentration, and temperature on this process were studied in detail. Five novel compounds were derived, including four oxaazaisowurtzitanes comprising one to three aza groups, and one condensation intermediate. The most favorable conditions for the formation of the resultant caged compounds were established and some new regularities of the process were revealed. For instance, the reaction medium concentration was discovered for the first time to influence the generation process of oxaazaisowurtzitanes via direct condensation. The limiting stage of the cage formation process of oxaazaisowurtzitanes was identified. The formation rate of the oxaazaisowurtzitanes was shown to be dependent on their structure. The factor dramatically reducing the yield of the oxaazaisowurtzitanes at elevated synthesis temperature was also revealed.