 benzene, toluene, chlorobenzene or xylene, ethers, such as diethyl ether or methyl tert-butyl ether, or carboxylic esters, such as ethyl acetate, and be liberated again using a base. 
The reaction is carried out under the following conditions: the solvents used are, for example: halogenated alkanes, such as 1,2-dichloroethane or methylene chloride, aromatic compounds, such as benzene, toluene, chlorobenzene, nitrobenzene, or an excess of the dialkyl disulfide as solvent. Preference is given to using excess dialkyl disulfide as solvent. The temperature for the reaction is from 40xc2x0 C. to 150xc2x0 C., preferably from 50 to 100xc2x0 C., particularly preferably from 60 to 90xc2x0 C. The reagents used are organic nitrites (Rxe2x80x94ONO), such as, for example, alkyl nitrites, preferably n-butyl nitrite, (iso)amyl nitrite or tert-butyl nitrite. Here, R is any organic, chemically inert radical which does not have any effect on the actual reaction. R is, for example, a C1-C6-alkyl or C2-C6-alkenyl group.
In the reaction of the compounds, the stoichiometric ratios are, for example, as follows: 1-3 equivalents of alkyl nitrite, preferably 1-1.5 equivalents of alkyl nitrite. The following catalysts may be used: copper powder, elemental copper in a different form, such as, for example, turnings, wire, granules, pellets, rods; copper(I) salts, for example copper(I) chloride, copper(I) bromide or copper(I) iodide, copper(II) salts, or elemental iodine, particularly preferably copper powder. When carrying out the reaction in the solvent, 1-3 equivalents of dialkyl disulfide, preferably 1-2 equivalents, are employed. In a preferred embodiment, an excess of dialkyl disulfide is employed as solvent and then recovered by distillation. For further reactions, the product can be used without further purification. If appropriate, it is also possible to purify the product beforehand by distillation or crystallization using suitable solvents, for example from diisopropyl ether. 
The bromination is carried out similarly to the method 