| 摘要 |
<p>A novel process is described for the preparation of compounds of formula <IMAGE> wherein R2 and R3 are each chloro or bromo; X is carboxyl, nitrile, optionally substituted carbonamide, carbonyl halide or an ester group. Those compounds wherein X is an appropriate ester group -COOB where B is an aryl group such as m-phenoxybenzyl are known insecticides; compounds where X is other than -COOB may be suitably converted thereto. The novel process consists of a series of steps from the corresponding acetyl compound of formula <IMAGE> which comprises halogenation, reduction, esterification and finally elimination reactions.</p> |
