New Macrocyclic Ligands.XVI.~* Synthesis of a Series of N-Benzylated Macrocycles Incorporating N_4O_2-Donor Sets

摘要

The synthesis of five 20-membered,N-benzylated macrocyclic ligands incorporating N_4O_2-donors sets and from one to three benzyl substituents for use in metal-ion recognition studies is described.The new derivatives were obtained by both benzylation of the pre-formed parent macrocycle using benzyl chloride in acetonitrile in the presence of base or,in one case,by performing macrocyclic ring closure using the appropriate N-benzylated triamine precursor by means of a bis-Schiff base condensation with the corresponding dialdehyde,followed by in situ reduction of the diamine linkages so formed.The single crystal X-ray structure of the symmetrically substituted,di-N-benzylated derivative is reported.