Highly substrate selective nucleophilic amination of nitro-substituted 4-(2-hydroxyethylamino)phthalazin-1(2h)-ones

An unexpected selectivity was observed in the aromatic displacement reaction of 4-(2-hydroxyethylamino)phthalazinones (1) under bar-(3) under bar and (7) under bar, (8) under bar differently substituted with the leaving nitro group on the condensed benzene ring. On treatment with a series of amine and hydrazine nucleophiles, the 8-nitro isomers (1) under bar-(3) under bar were readily transformed into the corresponding aromatic amine ((4) under bar-(6) under bar), while the substrates carrying the nitro group at position 6 or 7 ((7) under bar and (8) under bar) remained unchanged on prolonged treatment with any of the reagents used. Application of pyridine or DMF as a solvent proved to be indispensable to successful conversions even of the 8-nitro derivatives (1) under bar-(3) under bar.Accession Number: WOS:00007207550001