cis-Diprotected cyclams and cyclens: a new route to symmetrically or asymmetrically 1,4-disubstituted tetraazamacrocycles and to asymmetrically tetrasubstituted derivatives
Abstract
The use of cyclam and cyclen oxamides as intermediates for the synthesis of N 1,N 4-disubstituted tetraazamacrocycles is reported. This pathway affords a general strategy for the preparation of symmetrically or asymmetrically disubstituted derivatives in good yields. Also these intermediates proved convenient synthons for the preparation of asymmetrically tetrasubstituted macrocycles, leading to a new class of potentially dinucleating ligands.