Phenanthrolines quaternization

Sykes has studied a number of substituted 4,7-phenanthrolines (148). Since the ring system is symmetrical, as is also the case with the 1,10-compound, the position of quaternization is controlled by the substituents. In the first paper, 5-acetamido, -bromo, and -chloro... 

The first diquaternary salt (67) of 1,7-phenanthroline was prepared using trimethyloxonium fluoroborate in nitromethane.15 The salt is immediately demethylated in the 1-position in dimethyl sulfoxide, trifluoroacetic acid, or water to give 68. If ethylene chloride is used as quaternizing solvent, the monoquaternary salt (68) is obtained. 

Phenanthroline is preferentially quaternized at the 9-position and gives a 1,9-dimethyl diquaternary salt with trimethyloxonium fluoroborate in nitromethane. This diquaternary salt also is readily demethylated in the 1-position.15... 

Four chapters in the present volume bring older reviews up to date. Those on the quinoxalines (Cheeseman and Werstiuk) and on hetero-aromatic quaternization (Zoltewicz and Deady) carry forward contributions on the same subjects in Volumes 2 (1963) and 3 (1964), respectively, of this Series, while those on the phenanthrolines (L. A. Summers) and the isatogens and indolones (Hiremath and Hooper) deal with topics previously covered elsewhere. The cyclazines, a relatively new field of chemistry, are reviewed by Flitsch and Kramer, and the azapentalenes— the wide variety of nitrogen-containing heterocycles formed by the fusion of two aromatic five-membered rings—are collected into one chapter by Elguero, Claramunt, and A. J. H. Summers. 

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