Diiodo--nitroaniline

Diiodo- -nitroaniline has.been made by the action of iodine chloride on a chloroform solution 1 and also on a glacial acetic acid solution 2 of />-nitroanilinc. 

Diazonium salt solutions that have been obtained from weakly basic amines in concentrated H2S04 with nitrosylsulfuric acid and 85 % phosphoric acid give good yields of the derived aryl iodides when treated with cold aqueous KI for example, the preparation of 1,2,3-triiodo-5-nitrobenzene from 2,6-diiodo-4-nitroaniline is described in detail in Organic Syntheses 1223 and m-iodonitrobenzene, l,2-diiodo-4-nitrobenzene, l,4-diiodo-2-nitrobenzene, and 1,2,4-tri-iodo-3-nitrobenzene have been obtained analogously.1224... 

When the ester (4) is coupled with diazonium salts from p-nitroaniline, 3,4,5-triiodoaniline, or 3,5-diiodo-p-anisidine (NH2 = 1), the unstable azo compounds (5) can be isolated as crystalline intermediates, which, however, pass into the hydrazones if warmed or treated with dilute alkali.333 334 In recent years,335 however, the isolation of various, relatively stable aliphatic arylazo compounds has been reported. 

By contrast, 2,6-dik)do-4-nitromethoxybenzene in ethanol solution underwent displacement of the methoxy group by dropwise treatment at OX with excess isopropylamine followed by completion of reaction at ambient temperature during 2 hours to afford, in 70% yield, N-isopropyl 2,6-diiodo-4-nitroaniline. Secondary amines resulted simply in dealkylation to give the corresponding phenol (ref.57), a difference probably due to the influence of a differing degree of steric hindrance. 

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