Process for the preparation of cypermethrine isomers
US5153349A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1990 |
| Grant date | Oct 6, 1992 |
| Priority date | — |
| Expiry date | Oct 19, 2010 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA01N53/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a process for the preparation of such isomer mixtures of cypermethrine of the Formula (I) ##STR1## wherein carbon atoms indicated by 1, 3 and .alpha. stand for a chiral carbon atom and the wavy line indicates cis or trans configuration related to the cyclopropane ring--which contains out of the theoretically possible 8-isomers of cypermethrine at least 95% of 1RtransS and 1StransR (Ib) isomer pair or only a mixture of 1RcisC and 1ScisR (Ia) and the isomer pair (Ib) of the ratio (Ia):(Ib)=55:45-25:75 by asymmetric transformation of second order performed in the presence of an amine base and solvent from a starting cypermethrine isomer mixture which contains next to the isomer pair (Ib) cis and other trans isomers or the isomer pair Ia+Ib at an undesired ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.