A New Synthesis of Cyclen (1,4,7,10-Tetraazacyclododecane)

摘要

The new synthesis affords cyclen (1) in two synthetic steps with an overall yield of 57%. No protecting groups are required and solvent requirements are modest in comparison to the Richman-Atkins synthesis. The sequence can be regarded as involving a "permanent covalently-bound template" consisting of the two carbon unit that is introduced in the first step and ultimately converted to the new ethylene bridge of 1. Additional methods for synthesis of 2 and related compounds are being actively investigated, as is the applicability of the approach presented here to the synthesis of other macrocyclic tetraamines.