| 摘要 |
<p>Aryl-dichloro-methylpropenes of the general formula <FORM:0724818/IV (b)/1> where R is a chlorine, bromine or hydrogen atom or an alkyl or alkoxy radical of 1-4 carbon atoms are prepared by reacting chloretone with a benzenoid compound of the formula <FORM:0724818/IV (b)/2> in the presence of anhydrous aluminium chloride. Suitably the reaction is carried out at 60-150 DEG C., preferably in the range 80-125 DEG C. using 0.25 to 0.75 mole of aluminium chloride per mole of chloretone. The reaction products may be separated by adding the reaction mixture to a mixture of crushed ice and strong mineral acid, separating the oily organic layer, extracting the aqueous layer with ether, combining the ether extracts with the organic layer, evaporating to remove the ether, and separating the products by fractional distillation under reduced pressure. The reaction mixture contains a -chloroisobutyric acid formed as a by-product, which is also separated by fractional distillation. In examples there are prepared (1) 3 - (4 - chlorophenyl) - 1 : 1 - dichloro - 2-methylpropene-1; (2) 3-(4-bromophenyl-1 : 1-dichloro-2-methylpropene-1; (3) 3-phenyl-1 : 1-dichloro-2-methylpropene-1; (4) 3-tolyl-1 : 1-dichloro-2-methylpropene-1 (mixed isomers), and (5) 3-(4-methoxyphenyl)-1 : 1-dichloro-2-methylpropene-1.</p> |
