Para-Bromoaniline

Aromatic nitriles were obtained in high yield when para and meta substituents were present on the aromatic nucleus. Among the para substituted aryl halides p-nitrochlorobenzene and p-bromoaniline did not... 

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... 

Somewhat similar methods are used in the preparation of bromo-anilines. Consider, for example, the preparation of p-bromoaniline. The action of bromine on aniline gives quantitatively 2, 4, 6-tribro-moaniline. If aniline is first acetylated and then brominated, ortho-and poro-bromoacetanilides are formed with the para isomer predominating. The ortho compound is more soluble in alcohol than the para isomer, and thus can be removed by crystallization. The p-bromoacetanilide is then hydrolyzed. A variation of this method is to add bromine very slowly to aniline dissolved in a large excess of glacial acetic acid, when p-bromoaniline is directly formed, thereby eliminating acylation and hydrolysis. 

---