Synthesis of three new macrocyclic tetraamide ligands

A facile route is described for the synthesis of a series of macrocyclic tetraamides 1, 4, 9, 12-tetraazacyclo-2, 3, 6, 7, 10,11,14,15-tetrabenzocetanan-5, 8, 13, 16-tetraone (TCTCT), 1, 4, 10, 13-tetraazacyclo-2, 3, 6, 8, 11, 12, 15,17-tetrabenzo-octadecan-5,9,14,18-tetraone (TCTOT) and 1,4,10,13-tetraaza-cyclo-2, 3,11,12-dibenzo-6,8,15,17-dipyrdyl-octadecan-5,9,14,18-tetraone (TCPOT) derived from 1,2-diaminobenzene based on a stepwise approach using diacid dichloride (1,2-diacid dichloride benzene, 1, 3 - diacid dichloride benzene, 2, 6 - diacid dichloride pyridine) or mix dianhydrides for ring closure. This method is applicable for the preparation of a variety of receptors of various ring size, heteroatom substitution and pendant chains.