5-Benzyl-3-furylmethyl Chrysanthemate: a New Potent Insecticide

Abstract

FOLLOWING earlier work¹, we have synthesized more non-ketonic esters of chrysanthemic acid. One new compound, 5-benzyl-3-furylmethyl (+)-trans-chrysanthemate (I), is fifty-five times as toxic to adult female Musca domestica L. (house-flies) as the mixed esters of the natural pyrethrins, nearly three times as toxic as parathion and more than five times as toxic as diazinon. The same ester is ten times as toxic to adult Phaedon cochleariae Fab. (mustard beetles) as the natural pyrethrins and thirteen times as toxic as parathion. The (±)-cis-trans-clarysanthemate (m.p. 43–48°) is the most toxic compound tested so far, of any class of insecticide, to 1–2 day old unfed females of Anopheles stephensi and Aedes aegypti (results provided by Dr. A. B. Hadaway). This insecticidal activity is greater than has been found before in a compound containing only carbon, hydrogen and oxygen. By contrast, its acute toxicity to mammals seems to be small; for example, the median lethal dose to female rats for the (±)-cis-trans-chrysanthemate administered orally is between 600 and 800 mg/kg (personal communication from Dr. J. M. Barnes).