Synthesis of imines, diimines and macrocyclic diimines as possible ligands, in aqueous solution

Although it is recognized that the presence of water is disadvantageous for imine synthesis, we demonstrate that such synthesis can be effective in co mpletely aqueous media, without any catalyst and under mild conditions. Thu s, aryl-aryl, aryl-alkyl., alkyl-aryl and alkyl-alkyl monoimines as well as a large variety of diimines are obtained by direct condensation of the cor responding carbonyl compounds and amines, in water. The same process is use d to synthesize macrocyclic diimines starting from methylene, ethylene, tri methylene and tetramethylene glycol bis(2-formylphenyl ether) and ethylene- , trimethylene- and tetramethylene-diamine, some of these macrocycles being known for their chelating properties.