The one-pot halomethylation of 5-substituted salicylaldehydes as convenient precursors for the preparation of heteroditopic ligands for the binding of metal salts

The one-pot bromo- and chloro-methylation of various 5-substituted salicylaldehydes with paraformaldehyde and hydrobromic or hydrochloric acid has been achieved. This approach establishes a convenient and flexible method to attach functional arms to salicylaldehydes for further applications in organic and coordination chemistry. Examples are described using 3-bromomethyl-5-t-butylsalicylaldehyde in the synthesis of piperazine-containing heteroditopic ligands as receptors for metal salts.