P- Bromoaniline

The p-bromoaniline separates as an oil, which soon sohdifies. Filter at the pump and wash with cold water. Purify the crude p-bromoanihne aa follows. Dissolve it in a mixture of 120 ml. of water and 75 ml. of concentrated hydrochloric acid, add 1-2 g. of decolourising carbon, and warm on a water bath for 10 minutes. Filter through a fluted paper or through two thicknesses of filter paper on a Buchner funnel. Pour the filtrate slowly and with vigorous stirring into a mixture of 60 ml. of 10 per cent, sodium hydroxide solution and 100 g. of crushed ice. Thep-bromo-aniline crystallises out. Filter, etc. as in Method 1. The yield is 11 5 g. 

Bromodiphenyl. Diazotise 43 g. of p-bromoaniline (Section IV,49) in the presence of 40 ml. of concentrated hydrochloric acid and 22 -5 ml. of water (see Section IV,61) with a concentrated solution of sodium nitrite. Mix the filtered diazonium solution with 500 ml. of cold benzene, stir vigorously and add a solution of 30 g. of sodium hydroxide in 150 ml. of water dropwise (during 30-45 minutes) whilst maintaining the temperature at 5-10°. Complete the reaction as for 2-chlorodiphenyl. The 5rield of 4-bromodiphenyl, b.p. 170-175°/8 mm., m.p. 90° (from ethanol) is 25 g. 

Reagents and conditions i, p-bromoaniline or p-aminobenzonitrile, CHCI3 ii, hv, toluene/methanol (10 1) Scheme 10... 

Further examination of the extracts of A. cannabina revealed axisonitrile-4 (7), axisothiocyanate-4 (8) and axamide-4 (9) [33], A vinylic isonitrile function was supported by H NMR signals at <51.67 and 1.89, which were assigned to the two isopropylidene methyls of 7. Difficulty in isolating the natural product 9 was circumvented, when isonitrile 7 was transformed to 9, mp 81-84 °C, by acetic acid in anhydrous ether. The absolute configurations of both axanes 1 and 7 and their analogs were later established [31] by studies including X-ray diffraction of the p-bromoaniline derivative of 2 and by CD data of ( + )-10-methyldecalone-l obtained from ozonolysis of the reduction (Na/NH3) product of 1 [1]. 

By careful choice of both the reaction conditions and the phenolic compound used, it may be possible to produce a colour that is characteristic of a particular carbohydrate or related group, so giving some degree of specificity to the method. Thus, Seliwanoff s test uses hydrochloric acid and either resorcinol or 3-indolylacetic acid to measure fructose with minimal interference from glucose. The colour produced by pentoses with orcinol (Bial s reagent) or p-bromoaniline is sufficiently different from that produced by hexoses to permit their quantitation in the presence of hexoses. However, none of the methods based on the formation of furfural or its derivatives can be considered to be entirely specific. 

Similarly, benzene and hydrazoic acid in the presence of a mixture of fluorosulphonic and trifluoromethanesulphonic acid give aniline quantitatively. From toluene 100% of a mixture of o-, m- and p-toluidines is obtained and bromobenzene yields 42% o-bromoaniline and 47% p-bromoaniline, Butyl azide gives iV-butylarylamines under these conditions89. Photolysis of 1-aminoquinolinium perchlorate (76) in aromatic hydrocarbons (benzene, toluene, ethylbenzene or mesitylene) in the presence of 18-crown-6 affords arylamines, e.g. aniline and p-toluidine, by way of the nitrenium ion90 cf Reference 91. 

Dibromobiphenyl, see Biphenyl 4,4 -Dibromobiphenyl, see Biphenyl Dibromochloroaniline, see p-Bromoaniline Dibromochlorophenol, see p-Bromophenol. Phenol... 

CASRN 106-40-0 molecular formula CeHeBrN FW 172.02 Chemical/Physical. Hypochlorous acid reacted with p-bromoaniline forming bromochloro-aniline, bromodichloroaniline, dibromoaniline, and dibromochloroaniline. The displacement of bromine atom by chlorine yields hypobromous acid which then displaces a hydrogen atom from another brominated compound forming additional brominated compounds, e.g., bromochloro-aniline, bromodichloroaniline, etc. (Hwang et al., 1988). 

Time, as well as acid concentration, is a factor controlling the nature of the product. Thus p-bromoaniline and cyanoguanidine successively yield the corresponding biguanide and amidinourea, either of which may be isolated at the appropriate time 729). 

Mono-substitution products of primary amines cannot easUy be prepared by direct action of the appropriate reagent for example, bromination of aniline yields largely the 2 4 6-tribomo derivative and nitration results in much oxidation. If, however, the amino group is protected as in acetanilide, smooth substitution occurs. Thus with bromine, p-bromoacetanilide is the main product the small quantity of the ortho isomeride simultaneously formed can be easily eliminated by crystallisation. Hydrolysis of p-bromoacetanilide gives p-bromoaniline ... 

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