Synergistic effects of some compounds related to 2‐diethylaminoethyl 2,2‐diphenyl‐n‐pentanoate (SKF 525A) on the insecticidal activity of pyrethrins

Abstract

A number of compounds related to SKF 525A were tested for synergism with pyrethrins, using Lesser Mealworm beetles, Alphitobius laevigatus, and houseflies, Musca domeslica, as test insects. SKF 525A had previously been shown to be active, whereas 2.2-diphenyl-n-pentanoic acid and 2-diethylaminoethanol were inactive. Several active compounds resulted from esterification of 2-diethylaminoethanol with diphenylacetic acid and I-substituted diphenylacetic acids. Most modifications of the alcoholic moiety of active 2-diethylaminoethyl esters destroyed activity. Active compounds resulted when a a-diethylamino group was joined to a diphenylmethyl group through an ester, ketone or ether linkage, but the analogous amide was inactive. 2-Diethylaminoethyl piperonylate probably owed its activity to its piperonyl group. None of the compounds investigated approached piperonyl butoxide in synergistic activity. IntroductionThe ester 2-diethylaminoethyl z,z-diphenyl-n-pentanoate (SKF 525A, see Table I) ,is well known to increase the effects on mammals of drugs of a number of different types.1 Moreover, it has been shown to synergise the action of pyrethrins on certain insects2 In the work described here, a number of compounds related to SKF525A have been tested for action as pyrethrin synergists on insects, in order to relate chemical structure to biological activity. Variation of the acid and alcohol components established sufficient conditions for synergism in esters. The effects of different linkages between the terminal moieties of the molecule were then examined.

Mixed-function oxidase involvement in the biochemistry of insecticide synergists

“…Synergistic activity with insecticide chemicals is not restricted to MDP compounds because other materials are sometimes as active or even more active. These include, for example, compounds of varying synergistic potency with A-alkyl groupings such as: SKF 525A, as the free base (XV), and related compounds (Bates et al, 1965;Hewlett et al, 1961;Metcalf and Fukuto, 1965;O'Brien, 1961);…”