| 摘要 |
<p>PCT No. PCT/GB95/02570 Sec. 371 Date Jan. 31, 1997 Sec. 102(e) Date Jan. 31, 1997 PCT Filed Nov. 2, 1995 PCT Pub. No. WO96/16018 PCT Pub. Date May 30, 1996The invention provides an improved process for the preparation of a lower alkyl ester of 3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropane carboxylic acid in which the corresponding lower alkyl ester of a carboxylic acid selected from 6-bromo-6-chloro-3,3-dimethyl-7,7,7-trifluorohept-2-enoic acid and 6,6-dichloro-3,3-dimethyl-7,7,7-trifluorohept-2-enoic acid is treated with an alkali metal lower alkoxylate in the presence of an aromatic hydrocarbon solvent under conditions under which the lower alcohol of the alkoxylate is removed from the reaction mixture by distillation with the aromatic solvent. The products are useful as intermediates in the manufacture of pyrethroid insecticides.</p> |
