Potassium Hydroxide → 1-Cyano-2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarboxylic acid

Temperature

35 °C

Methyl 4-bromo-2-cyano-3,3-dimethyl-6,6,6-trichlorohexanoate (64.0 g, 0.166 m) was added over a period of 25 minutes to a suspension of potassium hydroxide (120.0 g, 1,8 m) in methanol (2100 ml) at 20° C. The mixture was then stirred for 1 hour at 35° C. and subsequently heated under reflux for 2.5 hours. The solvent was then removed under reduced pressure and the residue was dissolved in water (1500 ml). The aqueous phase was washed once with dichloromethane and acidified with concentrated hydrochloric acid to about pH 1. The mixture was then extracted three time with dichloromethane and the extracts were dried. The solvent was removed under reduced pressure to yield the required acid 1-cyano-2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarboxylic acid, as a white crystalline solid (m.p. 128°-132° C., yield 37.6 g, 97%). The NMR spectrum of the compound measured at 60 MHz in deuterochloroform solution showed the following absorptions relative to a tetramethylsilane standard. On the basis of the spectrum it was established that the product consisted of two geometric isomers, Z and E, in the ratio Z:E=56:44.

1. temperaturesubsequently heated
2. temperatureunder reflux for 2.5 hours
3. customThe solvent was then removed under reduced pressure
4. dissolutionthe residue was dissolved in water (1500 ml)
5. washThe aqueous phase was washed once with dichloromethane
6. extractionThe mixture was then extracted three time with dichloromethane
7. customthe extracts were dried
8. customThe solvent was removed under reduced pressure

ORD record

ord-433f39bfce9b42ddb666c3888ed9c7fd

Source dataset

uspto-grants-1980_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04211720