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Two general procedures have been used hitherto for the preparation of organometallic derivatives of carbazole.' One of these involves a direct synthesis from R X compound and magnesium or lithium in poor yields. The other is a metalation reaction which also suffers from the disadvantage of low yields; however, this is compensated by the introduction of the metal in positions not generally accessible by other nuclear substitution reactions. The halogen-metal interconversion reaction now reported is one of choice for three reasons: (1) the highly satisfactory yields from monohalogen derivatives; (2) the splendid yields of dimetallic compounds from di-halogen derivatives; and (3) the possibility of effecting preferential X-M interconversion with di-halogen derivatives.An illustration of di-metal formation is the reaction of 5-ethyl-2,8-dibromocarbazole with nbutyllithium to give, subsequent to carbonation, an 8470 yield of dibasic acid. Brc-/\;Br[2n-C4HsLi] 9 1

Some Quinolines Patterned as "Open Models" of Atabrine 621 needles were obtained which melted at 220°with sublimation. The yield was 55 mg. corresponding to 96% of the theoretical.

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The availability of 2-pyridyllithium (1) by the halogen-metal interconversion reaction expands the possibilities to other 2-pyridyl types.In a reaction between diphenyllead diiodide and 2-pyridyllithium, a mixture of organolead compounds was obtained. This mixture may be due to both disproportionation or redistribution (2) and to metal-metal interconversion reactions.Since metal-metal interconversion occurs to a lesser extent with RMgX than with RLi compounds, the 2-pyridyllithium was converted to 2-pyridylmagnesium bromide with magnesium bromide (3). This Grignard reagent then reacted smoothly with diphenyllead diiodide to give diphenyl-2-pyridyIíead iodide in 63% yield.2-CJÍ4NLÍ + MgBr2 -> AC5H4NMgBr + LiBr (C6H5)2PbI2 + AC6H4NMgBr -e (C6H6)2(C6H4N-S)PbI + MgBrI The diphenyl-2-pyridyllead iodide reacted with phenylmagnesium bromide to give triphenyl-2-pyridyllead. Interestingly enough, the 2-pyridylmagnesium bromide appeared not to react appreciably with triphenyllead iodide. Also, no metal-metal interconversion occurred at -50°between triphenyl-2-pyridyllead and n-butyllithium.The reactivity of 2-pyridyllithium relative to that of phenyllithium was of interest to other studies. One of the reagents used earlier (4) for some rate studies was benzonitrile. Its reaction rate with 2-pyridyllithium was, however, too rapid. Accordingly, p-methoxybenzonitrile was used because of its decidedly lesser activity. It was found that 2-pyridyllithium reacts much less rapidly with -methoxybenzonitrile than does phenyllithium. Interestingly, in the presence of benzene, the reaction rate with the nitrile is accelerated, probably as a result of a diluent effect by the benzene on the coordination tendencies between the RLi compound and the ethyl ether. The high yield (83-86%) of product, 2pyridyl p-methoxyphenyl ketone, shows that the interconversion reaction between 2-bromopyridine and n-butyllithium is very satisfactory and that the lower yields of some products from 2-pyridyllithium are probably due to secondary transformations.In addition to the formation of several 2-pyridylmetallic types, it was shown that 2-pyridyllithium adds to quinoline at -20°to give 2-pyridyl-2'-quinoline.