Straightforward Three-Component Synthesis of N′,N′′-Disubstituted N-Alkyl-1,3,5-Triazinanes

Recent Advances of 1,3,5-Triazinanes in Aminomethylation and Cycloaddition Reactions

1,3,5-Trisubstituted 1,3,5-triazinanes (hexahydro-1,3,5-triazines), as stable and readily available surrogates for formaldimines, have found extensive applications for the construction of various nitrogen-containing compounds. The formaldimines, formed in situ from this reagent class, can participate in various aminomethylation and cycloaddition­ reactions. This short review presents recent advances in this field with emphasis on the conceptual ideas behind the developed methodologies and the reaction mechanisms.

1 Introduction

2 Aminomethylations with 1,3,5-Triazinanes

3 Cycloadditions with 1,3,5-Triazinanes

3.1 Use of 1,3,5-Triazinanes as Two-Atom Synthons

3.2 Use of 1,3,5-Triazinanes as Three-Atom Synthons

3.3 Use of 1,3,5-Triazinanes as Four-Atom Synthons

3.4 Use of 1,3,5-Triazinanes as Six-Atom Synthons

4 Conclusions

Intramolecular sp2-sp3 Disequalization of Chemically Identical Sulfonamide Nitrogen Atoms: Single Crystal X-Ray Diffraction Characterization, Hirshfeld Surface Analysis and DFT Calculations of N-Substituted Hexahydro-1,3,5-Triazines

In this manuscript, the synthesis and single crystal X-ray diffraction characterization of four N-substituted 1,3,5-triazinanes are reported along with a detailed analysis of the noncovalent interactions observed in the solid state architecture to these compounds, focusing on C–H···π and C–H···O H-bonding interactions. These noncovalent contacts have been characterized energetically by using DFT calculations and also by Hirshfeld surface analysis. In addition, the supramolecular assemblies have been characterized using the quantum theory of “atoms-in-molecules” (QTAIM) and molecular electrostatic potential (MEP) calculations. The XRD analysis revealed a never before observed feature of the crystalline structure of some molecules: symmetrically substituted 1,3,5-triazacyclohexanes possess two chemically identical sulfonamide nitrogen atoms in different sp2 and sp3-hybridizations.