Hydrochloric Acid → 2-Chloro-1-iodo-4-methylbenzene

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

250 ml of concentrated hydrochloric acid and 75 g of 4-amino-3-chlorotoluene (0.53 mol) are introduced onto 166 g of ice, and a solution of 40.3 g of sodium nitrite (0.583 mol) in 170 ml of water is then added dropwise at 0° C. After the solution has been stirred for 15 minutes, it is filtered through glass wool, and the solution, which has been cooled to -2° C., is added dropwise to a solution, warmed to room temperature, of 455 g of potassium iodide (2.74 mol) in 1 l of water together with a batch prepared analogously with 0.30 mol of 4-amino-3-chloro-toluene. After the reaction mixture has been stirred overnight, it is extracted three times with ether and the combined organic phases are washed twice with dilute sodium hydroxide solution, twice with dilute sodium bisulphite solution and with water. After drying over sodium sulphate, filtration and concentration, the residue of copper powder is distilled over a Vigreux column under 1 mm Hg. The fraction between 70° and 85° C. gives 149 g of a yellow oil [7% of theory, Rf =0.57 (hexane:ethyl acetate=9:1)].

Herkunft & Nachweise