Reactions of co-ordinated ligands. Part III. Reactions of Schiff bases co-ordinated with magnesium. A preparation of 3-aminocoumarin

Abstract

The magnesium chelates of the Schiff bases derived from salicylaldehyde and the ethyl and methyl esters of glycine have been prepared. 3-Aminocoumarin is formed when these chelates are heated under reflux in dry methanol, and when the ethyl ester Schiff base is treated with magnesium methoxide or sodium methoxide in methanol; the last reaction provides a convenient preparation of the amine. The ester groups in the chelates are very reactive towards nucleophiles; examples of hydrolysis, ester exchange, and amide formation, all occurring rapidly under mild conditions, have been observed.