Bulky alkylaminophenol chelates with high potential for functionalization

Abstract

Aminophenols are an important class of N,O-ligands, particularly for the coordination of first-row transition metals. While their structural and electronic character and the additional possibility of bioactivation are well appreciated in coordination chemistry, particularly of responsive systems, the synthesis of the more branched and structurally demanding models is still a challenge. Therefore, the synthesis of bulky bis(hydroxybenzyl)-N'-(aminopyridyl)propanamines is described here. It consists of the Mannich reaction of 2,4disubstituted phenols with 3-aminopropan-1-ol and paraformaldehyde to N,N-bis(2hydroxybenzyl)-3-aminopropan-1-ol. Substitution of the hydroxyl group with chlorine followed by amination with 2-(aminomethyl)pyridine results in bulky pentadentate N,Oligands with a free site on the nitrogen atom for further functionalization. The method features good yields and high selectivity, and the products are well identified by spectroscopic methods.