NITRATION IN THE CARBAZOLE SERIES

Article abstract of DOI:10.1016/S0040-4020(01)91140-8

Nitration of 9-tosylcarbazole in acetic anhydride solution gives 1-nitro (28percent), 2-nitro (19percent) and 3-nitro (53percent) derivatives.The mixture of the nitro compounds obtained from 9-acetylcarbazole contains 10percent, 48percent and 42percent of the isomers, respectively.Under similar conditions 9-nitrosocarbazole shows a different isomer distribution: 34percent of 1-nitro and 66percent of 3-nitrocarbazole.Nitration of carbazole is a two step process involving formation and rarrangement of 9-nitrocarbazole.The hypothesis was supported by the results of 1,3,6,8-tetrachlorocarbazole nitration and oxidation of 9-nitrosocarbazole and rearrengement of 9-nitrocarbazole in the nitration conditions.