Bromine solution, in carbon tetrachloride

To a solution of 80 mg of 1-(/3-D-arabinofuranosyl)-2-thiocytosine in 12 ml of water is added dropwise 3 ml of a 1 M bromine solution in carbon tetrachloride. At this point the color of the bromine persists for about 2-3 minutes after each addition. The unreacted bromine is blown off with a stream of nitrogen, and the reaction mixture is concentrated to a syrup in vacuo using a bath temperature less than 50°C. The residue is evaporated three times with 10 ml portions of ethanol, whereupon it crystallizes. The product is triturated with cold ethanol and with ether to obtain 17 mg of 2,2 -anhydro-1 -(/3-D-arabinofuranosyl)cytosine hydrobromide, MP 240°C (dec.). 

Bromine (I) fluoride, formation of, in preparation of BrF3, 3 185 Bromine(III) fluoride, 3 184 Bromine (V) fluoride, formation of, in preparation of BrF3, 3 185 Bromine solution, in carbon tetrachloride, 1 86... 

C) 2-Methy 1-2-Butene (Amylene) (Sm.) Add a few drops of amyl alcohol to 2 ml of bromine solution in carbon tetrachloride or bromine water. Shake, and note if there is any immediate decolorization. 

Chlorine adds to form the Zrans-dichloride bromine adds, in carbon tetrachloride solution, to give a mixture of as- and trans-dibromides this addition can be directed wholly to the trans derivative by conducting the bromination in a mixed phase reaction in aqueous suspension. 

Condensed aromatic hydrocarbons are more reactive towards electrophilic reagents, and naphthalene, for example, may be brominated quite readily in solution in carbon tetrachloride without the need for a catalyst electrophilic attack takes place at the more reactive a-position to yield 1-bromonaphthalene (Expt 6.25). 

The use of trifluoroacetic acid as a catalyst in the A -bromosuccinimide bromination of (73) in dilute solution in carbon tetrachloride gave improved yields of the 3-bromo derivative <79JHC1449>. 

An addition reaction is a reaction in which parts of a reactant are added to each carbon atom of a carbon—carbon double bond, which converts to a carbon—carbon single bond. (Addition to triple bonds is also possible, giving a product with a double bond.) The addition of Br2 to an alkene is fast. In fact, it occurs so readily that bromine dissolved in carbon tetrachloride, CCI4, is a useful reagent to test for unsaturation. When a few drops of the solution are added to an alkene, the red-brown color of the Br2 disappears immediately. 

Dibromine monoxide, BtjO, is prepared, similar to the corresponding dichlorine compound, by the action of a solution of bromine in carbon tetrachloride on yellow mercury(II) oxide ... 

The bromine test is applied first. The organic compound, if a liquid, is treated with 2-3 drops of liquid bromine or (preferably) a solution of bromine in carbon tetrachloride if the organic compound is a solid, it should first be dissolved in cold carbon tetrachloride or chloroform. The rapid absorption of the bromine (and consequent disappearance of the red colour) is a strong indication that the compound is unsaturated, and is therefore undergoing direct addition of the bromine. 

Unsaturated esters decolourise a solution of bromine in carbon tetrachloride and also neutral potassium permanganate solution. 

Bromine test. Dissolve 0 2 g. or 0 2 ml. of the compound in 2 ml. of carbon tetrachloride, and add a 2 per cent, solution of bromine in carbon tetrachloride dropwise until the bromine colour persists for one minute. Blow across the mouth of the tube to detect any hydrogen bromide which may be evolved (compare Sections III,6 and 111,11). 

Bromine in carbon tetrachloride and bromine water, (c) Ferric chloride solution. 

Unlike nitration. 2-amino-4-methylselenazole can be directly bromi-nated, using bromine in carbon tetrachloride solution, to give 2-amino-5-bromo-4-methylselenazole hydrobromide [m.p. 180°C (decomp.)] (19). The free base cannot be isolated. Use of excess of bromine can lead to destruction of the molecule. 

Analysis. Butenes are best characterized by their property of decolorizing both a solution of bromine in carbon tetrachloride and a cold, dilute, neutral permanganate solution (the Baeyer test). A solution of bromine in carbon tetrachloride is red the dihaUde, like the butenes, are colorless. Decoloration of the bromine solution is rapid. In the Baeyer test, a purple color is replaced by brown manganese oxide (a precipitate) and a colorless diol. These tests apply to all alkenes. 

Isolation of the pure a,0 -ieomer, A 250-mL Erlenmeyer flask equipped with a magnetic stirring bar is charged with the isomeric nitriles (20 g, 0.165 mol), prepared in Part A above, and carbon tetrachloride (20 mL). A solution of bromine in carbon tetrachloride (1/9, v/v, ca. 25-30 mL) is added dropwise until the color of excess bromine persists. The reaction vessel is cooled in an ice bath for 30 min, filtered by gravity and the solvent evaporated under reduced pressure. The crude oil is distilled at reduced pressure (bp 40-42 0/0,15 mm) to give a colorless liquid (11-15 g, 55-75%) which is the pure a.p-1somer (Notes 9 and 10). 

On treatment with bromine in carbon tetrachloride solution, it yields a dibromide in which two atoms of bromine have been fixed in the pro-penyl side chain, melting at 85° to 86°. 

Test for an alkene. At the left is a solution of bromine in carbon tetrachloride. Addition of a few drops of an alkene causes the red color to disappear as the alkene reacts with the bromine. 

B. Wet process Discussion. The sulphide is oxidised (1) by bromine in carbon tetrachloride solution, followed by nitric acid, (2) by sodium chlorate and hydrochloric acid, or (3) by a mixture of nitric and hydrochloric acids and a little bromine. The use of the first-named oxidising agent will be described the reaction may be represented by ... 

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