Metal template reactions. XXI. Synthesis and coordination chemistry of diamino dialdehydes based on pyrimidines and related enaminones

Abstract

4,6-Dichloropyrimidine-5-carbaldehyde (1) has been converted into the diamino dialdehydes (2)-(5). The related compound (6) could not be obtained but the pyrimido-diazepine (7) was formed instead. Copper(II) and nickel(II) complexes (8) were formed from the compounds (4) and (5). Forcing conditions were required for the formation of the macrocyclic complexes (9)-(12) from the precursors (4) and (5). The chloropyrimidines (2) and (3) underwent alkaline hydrolysis to give the enaminones (16) and (17) respectively. These compounds in turn gave rise to the complexes (21)-(23). Vigorous conditions were required for the formation of the macrocyclic complex (23) and the complex (22) was obtained by an amine exchange process.