Beiträge zur Chemie der Enolphosphate

Abstract

Following an introduction dealing with the chemistry of insecticidal phosphorus compounds and their biological effectiveness, the class of enol phosphate insecticides is described in particular. Enol phosphates are prepared by the Perkow reaction, i. e. the reaction of trialkyl phosphites with α-halo-carbonyl compounds. According to the nature of the α-halo-carbonyl compound, phosphonic acid esters may be formed (Arbusov reaction). By reaction of α-trihalo-amides with trialkyl phosphites neither enol phosphates nor phosphonic acid esters but trihalo-vinylamines are produced.
Surprisingly, a Perkow reaction was obtained upon addition of trialkyl phosphites to α-trichloro amides in which the N-atom was either acylated or combined with a –CO- or –SO₂-group, respectively. The preparation and properties of these new enol phosphates and particularly their behaviour on acid and alkaline hydrolysis are described. The comparison with the behaviour of some well-known enol phosphate insecticides shows interesting effects of the substituents.
These results have lead to general conclusions concerning the relationship between the rate of hydrolysis and the insecticidal effectiveness of enol phosphates.