Synthesis of a new triprotonated ligand and selective O-demethylation of methyl aryl ether by boron tribromide

Article abstract of DOI:10.1016/S0040-4039(99)00786-8

Selective O-demethylation of the ortho methyl catecholate of N,N',N'',- tris-(2,3-dimethoxybenzoyl)-1,1,1-tris-(L-methioninemehyl)-ethane (7) has been accomplished by boron tribromide. The intramolecular nucleophilic attack of divalent sulphur on methyl enhance this cleavage, favours this selectivity and consequently afford the triprotonated ligand N,N',N''-tris-(2-hydroxy-3- methoxybenzoyl)-1,1,1-tris-(L-methioninemethyl)-ethane (8) in a good yield.