M-Bromoaniline

This procedure may be employed for m-chlorobromobenzene, b.p. 191-194° from tn chloroaniline m-dibromobenzene, b.p. 215-217°, from m-bromoaniline and o-bromoanisole, b.p. 114 116°/29 mm. from o anisidine (the sulphuric acid washing is omitt in the last example). 

Phenols may be prepared by diazotization of the corresponding aniline derivative. The problem simplifies itself, therefore, to the preparation of m-bromoaniline. Recognizing that arylamines are ultimately derived from nitroarenes, we derive the retrosynthetic sequence of intermediates ... 

The preparation of m-bromoaniline from benzene has been described in Problem 22.17. All that remains is to write the equation for its conversion to m-bromoiodobenzene. 

Meta-substituted AB-type monomer such as m-bromoaniline also underwent Pd-catalyzed polycondensation [65], but the para counterpart has not been reported, possibly because aryl halides bearing the NH group in the para position are generally poor substrates for the aryl amination process. Buchwald et al. prepared a dimeric para-substituted AB monomer bearing the BOC protecting group and polymerized it with Pd2(dba)3 and 2-(di-ferf-bulylphosphino)biphcnyl [73]. The polymerization carried out at room... 

Sample Problem 18.8 Design a synthesis of m-bromoaniline from benzene. 

A hot solution of 50 g. (0.29 mole) of m-bromoaniline and 50 ml. of concentrated sulfuric acid in 400 ml. of water is cooled to 10° and diazotized by the addition of 21 g. (0.30 mole) of sodium nitrite at 10°. The solution of the diazonium salt is added (15-30 minutes) in a thin stream to a solution of 100 ml. of concentrated sulfuric acid and 300 ml. of water which is being steam-distilled during the addition at such a rate that, upon completion of the addition of the diazonium salt, approximately 1 1. of distillate has been collected. Steam distillation is continued until another liter of distillate has been collected. The distillate is saturated with sodium chloride and extracted three times with ether. The ether extracts are distilled to give 39 g. (78%) of 7n-bromophenol boiling at 125-130°/25 mm. 

Intermediates benzene to nitrobenzene to m-bromonitrobenzene to m-bromoaniline to m-bromophenol. Reagents HNO3, H2SO4 Br2, FeBrs Fe, HCl then HO NaN02, H2SO4, H2O, then heat in H2O. 

Prepare m-bromoaniline as in Problem 22.17 then NaN02, HCl, H2O followed by KI. 

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