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

The addition of tetrafluorobenzyne to benzene and mono-, di-, tri-, tetra-, and hexa-alkyl benzenes is described together with the additions to tetralins, naphthalenes and anthracene. In all these reactions only 1,4-addition products are isolated. The pyrolyses of some of the compounds isolated are reported. The proton magnetic resonance spectra of the products and the mass spectra of certain compounds are discussed.

A reductive dehalogenation of substituted 1,lO-phenanthrolines has also been n~t e d .~~~ Catalytic hydrogenation of 1,lO-phenanthroline with Raney nickel catalyst by a method similar to that adopted by Searles and Warrens for the reduction of 4,7-phenanthroline (2) afforded 1,2,3,4-tetrahydro-l,10-phenanthroline (1) in 80 % yield when the hydrogenation was carried out at 58 lb/sq in pressure at 20" for 40 h. There was no evidence for the formation of the 5,6-dihydro derivative analogous to (3) although Searles and Warrens obtained both (4), in 40 % yield, and (3), in 44 % yield, from the similar reduction of 4,7-phenanthroline. The structure of (1) was confirmed by elementary analyses and n.m.r. spectroscopy and by characterization of the derived hydrobromide salt. Hensen and Trobsl did not analyse compound (1) but characterized it by way of the dihydrochloride salt and the picrate. The tetrahydro-1,lOphenanthroline (1) afforded 1-acetyl-1,2,3,4,-tetrahydro-1,lO-phenanthroline by

Steroid 5,7-dienes undergo the ene-reaction with benzyne and tetrachloro-and tetrafluoro-benzyne. Tetrafluorobenzyne also forms a 5.8-adduct with a 5,7-diene and with a 5,7,9(11)-triene. Cholesta-2.4-diene gives 1.4-adducts with benzyne and tetrafluorobenzyne. The pyrolyses of some adducts are discussed. THE reaction of conjugated steroidal dienes in Diels-Alder addition reactions is well known.2 Recently, it has been shown that 5,7-dienes undergo an enereaction with a variety of dienophiles in addition to giving, in certain cases, the normal Diels-Alder pro-1

Sodium salts of drazoxolon and related 4-arylhydrazono-3- methylisoxazol-5-ones react with acyl chlorides in dry acetone to form 2-acyl-4-arylazo-3-methylisoxazol-5-ones, the structures of which were deduced from their i.r. and u.v. spectra. Several 2-acyl-4- arylazo-3- methylisoxazol-5-ones show considerable fungicidal activity against a number of plant pathogens.