1,l0-Phenanthroline-5,6-quinone is prepared from 1,l0-phenanthroline via 5-nitro-1,l0-phenanthroline and 5-amino-1,l0-phenanthroline. It is converted by standard methods into 4,5-diazafluoren-9-one, 4,5-diazafluoren-9-ol,4,5-diazafluorene, and the new heterocyclic system dipyrido[3,2-a:2',3'-clphenazine. These four compounds each form a complex with cupric chloride. They thus represent a new series of chelating agents. By reaction with ethylene dibromide, dipyrido[3,2-a:2',3'-c]-phenaiine forms a diquaternary salt which is reduced in aqueous solution by a one-electron transfer to a highly coloured radical cation. Polarography experiments show that the reduction potential of the salt is -0.40 V against a standard calomel electrode.

Abstract4,5-Diazafluoren-9-one is a co-product of the oxidation of 1,lO-phenanthroline with alkaline potassium permanganate along with 2,2'-bipyridyl-3,3'-dicarboxylic acid.4,5-Diazafluoren-9-one (1) has hitherto been a difficultly accessible compound, its only synthesi~l*~ being from the action of aqueous alkali on 1,lO-phenanthroline-5,6-quinone (2) by way of a benzilic acid type rearrangement analogous to the formation of fluorenone from phenanthreneq~inone.~ 1,lO-Phenanthroline-5,6-quinone (2), however, is much less readily prepared than phenanthrenequinone4 and is obtained at best in 15% overall yield by a tedious three-step synthesis from 1,lO-phenanthr~line.~ Consequently, the chemistry of 4,5-diazafluoren-9-one (1) has been neglected apart from studies of its reduction,lg5 its lack of participation in the Schmidt r e a~t i o n ,~ and exploratory chelation experimentse5 We now report a facile one-step synthesis of 4,5-diazafluoren-9-one (1) in about 20% yield by the oxidation of 1,lO-phenanthroline with alkaline permanganate.The oxidation of 1,lO-phenanthroline by aqueous alkaline potassium permanganate to give 2,2'-bipyridyl-3,3'-dicarboxylic acid (3) has been recorded several times, the acid (3) being the only product described in yields varying from

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The synthesis of several analogues of the chloralformamide fungicides is reported. The compounds, which comprise N-methyl-N-(2,2,2-trichloro- 1-arylaminoethyl)formamides and related alkoxyethyl and aryloxyethyl derivatives, exist at room temperature as two isomers due to restricted rotation about the C-N amide bond. The results of their evaluation as fungicides are reported.

Die Titelverbindungen (III) (verwandt dem Herbizid Diquat) und (VI) (verwandt dem Herbizid Paraquat) werden dargestellt.