The title compound (II) is obtained by nitrosation of the pyrazoline (I).

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Action of bromine in concentrated nitric acid allows carrying out mono-and polybromination of moderately deactivated aromatic compounds. 4-Chloronitrobenzene and isophthalic acid turnes into 3-bromo-4-chloronitrobenzene and 5-bromoisophthalic acid at reaction with bromine inconcentrated nitric acid at 20˚C whereas in absence of bromine in the same conditions 4-chloro-1, 3-dinitrobenzene and 5-nitroisophthalic acid are formed accordingly. Presence of bromine in concentrated nitric acid changes nitrating capacity to brominating one. Terephthalic acid and phthalic anhydride at heating with bromine in concentrated nitric acid can be transformed to appropriating tetrabromo substituted compounds.

1996amines amines (benzene compounds) Q 0120 -105Bromination of Anilinium Ions in para-Position in the Presence of Nitrosonium Hydrosulfate/Concentrated Sulfuric Acid.-On the basis of NMR measurements the para-bromination of various anilines is investigated. It is shown that the title reaction proceeds by in situ formation of para-bromobenzene diazonium salts which undergo fast coupling with the scavenger 2-naphthol. -(GORELIK, M. V.; LOMZAKOVA, V. I.; KHAMI-DOVA, E. A.; SHTEIMAN, V. YA.; KUZNETSOVA, M. G.; ANDRIEVSKII, A. M.; Zh. Org. Khim. 31 (1995) 4, 553-557; Nauchno-issled. inst. org. poluprod. krasitelei, Moskva, Russia; RU)