Pyridine radical anion, generated by alkali-metal reduction of pyridine shows an absorption maximum around 340 nm, the actual position varying with the counter-cation. The change in the spectra of the pyridine radical anion with time is due to formation of radical anions and dianions of 4.4'-, and 2.2'-bipyridyls. Alkylpyridines with substituents in the 3or 4-position form stable radical anions which do not undergo dimerization. Electron-withdrawing groups produce a bathochromic shift of the absorption band of the pyridine radical anion.KUWATA and his co-workers1 have reported that reduction of pyridine with sodium in tetrahydrofuran gives a purple solution with an absorption maximum at 570 nm due to the radical anion; these workers, however, observed time-dependent changes in the spectrum accompanied by some evolution of gas. Dodd and his co-workers2 have reported that the pyridine radical anion produced by the same method gives K. Kuwata, T. Ogawa, and K. Hirota, Bull. Chem. SOC.

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The reaction of nitrobenzene with lithium in tetrahydrofuran gave a mixture of products consisting of azobenzene, 2-anilinoazobenzene, 2,2'-and 2,4'-dianilinoazobenzenes, anilinodibenzopyridazine, and unidentified polymeric azo compounds. Similar products were obtained from the reaction of nitrosobenzene with lithium, whereas the reaction of azoxybenzene gave exclusively azobenzene. It has been suggested that radical anion intermediates are involved in these reactions. Substituted nitro compounds react in a manner analogous to that of nitrobenzene, whereas nitroamlines are unchanged under similar conditions. Compounds such as 4-bromoazoxybenzene and 2-chloronitrobenzene undergo both deoxygenation and dehalogenation reactions on treatment with lithium in THE. 2,2'-Dinitrobiphenyl, on the other hand, gave dibenzopyridazine and a trace of carbazole on treatment with lithium in ether solvents. Under similar conditions, however, 2,2 '-dinitrodiphenyl ether did not give any cyclized product.Aromatic nitro compounds, in general, are reduced in basic medium to the corresponding azoxy, azo, and hydrazo derivatives, whereas they are converted to the corresponding amines under strongly acidic conditions or under catalytic hydrogenation.2The deoxygenation of nitro and nitroso compounds have been brought about by several reagents to give a variety of products depending on the reaction conditions and the nature of the reagents.8 Aryl nitro compounds, for example, have been reduced to the corresponding azo derivatives in fairly good yields by metal hydrides4-6 and thallium.7The reaction of nitrobenzene with sodium in liquid ammonia is very complex and may warrant further investigation.8 However, sodium amalgam has been reported to reduce aromatic nitro compounds to the corresponding azoxy and azo compounds.2 Luka-shevich® had observed the formation of mono-and disodium adducts of nitrobenzene, as well as nitrosobenzene in ether solvents. Addition of alkali metals to nitro compounds in aprotic solvents has been reported to give rise to radical anion intermediates and several groups of workers have examined the esr spectra of some of these intermediates.10 We previously examined the electronic spectra of the radical anions of a few nitrobenzene derivatives and some

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