Organometallic complexes in synthesis. Part 16. Reactions of tricarbonyl(cyclohexadienyl)iron(1+) salts with aromatic amines

Tricarbonyl(cyclohexadienyl)iron(1+) salts of the type (1) cause C- or N-alkylation of aromatic amines depending on the conditions used. The best procedure involves formation of the salt in situ from an alkoxy-complex in the presence of a small proportion of acid. Attempts to extend the reaction to alkylate 6-amino-5,8-dimethylisoquinoline, to obtain an intermediate for the synthesis of ellipticine, resulted, instead, in irreversible alkylation at the pyridine nitrogen.