Preparation of cyclopropane carboxylic acid esters
US4332962A · kind A · utility
1Cited by
4References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 27, 1981 |
| Grant date | Jun 1, 1982 |
| Priority date | — |
| Expiry date | Feb 27, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C2601/02
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Process for the preparation of 3(2,2-dihalovinyl)-2,2-dimethyl cyclopropane carboxylic acids, especially permethrin acid ethyl ester, by reacting a diazoacetic acid ester with a 1,1-dihalo-4-methyl-1,3-pentadiene in the presence of a catalyst comprising a divalent rhodium salt of a carboxylic acid or borofluoric acid. The products have improved yields and better cis/trans isomer ratios than when the more common catalysts, e.g. copper-bronze, are used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.