Three-component synthesis of bridged 1,3,5-triazinanes

An efficient one-pot procedure has been developed for the synthesis of bridged 1,3,5-triazinanes, unexplored classes of heterocyclic polydentate scaffolds. By means of a pseudo five-component reaction between primary diamines (ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine), sulfonamides, and three equivalents of paraformaldehyde, a broad series of 1,3,5-triazabicyco[3.2.1]octanes, 1,3,5-triazabicyco[3.3.1]nonanes and 1,6,8-triazobicyclo[4.3.1]decanes were prepared. Boiling chloroform and an additive of Mg(ClO4)(2) were shown to be the most efficient conditions for the condensation. Putrescine is probably the longest diamine which can be involved in this protocol. It was demonstrated that cadaverine was unsuitable for preparation of corresponding 1,7,9-triazabicyclo[5.3.1]undecanes. The structure of all classes of the obtained azabicycles was elucidated by XRD analysis.