Research Progress of 1,3,5-Triazinanes in the Synthesis of Nitrogen-Containing Heterocycles

1,3,5-Triazinanes are an important class of synthons, which could be regarded as the equivalent of formaldehyde imines in constructing various nitrogen-containing heterocyclic skeletons.In recent years, 1,3,5-triazinanes have attracted much attention in the construction of nitrogen-containing heterocyclic compounds.Based on this, the participation of 1,3,5-triazinanes as diatomic, triatomic and four-atom synthons in [2＋n], [3＋n], [4＋n] cycloaddition reactions to construct nitrogen-containing heterocyclic compounds is systematically summarized.Its applications in cycloaddition, heterocyclic chemistry and pharmaceutical chemistry are also summarized.Moreover, the development of 1,3,5-triazinanes in the construction of nitrogen-containing heterocyclic skeletons and their future applications are also prospected.