2-Methyl-7-nitro-8-hydroxyquinoline

The case of i-methyl-4-quinolone is puzzling. The large proportion of the 3-nitro isomer formed in the nitration (table 10.3 cf. 4-hydroxyquinoline) might be a result of nitration via the free base but this is not substantiated by the acidity dependence of the rate of nitration or by the Arrhenius parameters. From r-methyl-4-quinolone the total yield of nitro-compounds was not high (table ro.3). 

An analogous reaction took place with some 6-substituted-2-methyl-4-quinolones and [hydroxy(tosyloxy)iodo]benzene [162] and also between 5-nitro-7-hydroxyquinoline and (diacetoxyiodo)benzene [163]. Depending on the solvent or the presence of alkali, either the iodonium salt or the 1,4-dipole could be isolated. 

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