Pyrethroic acids

Cyclopropanation of 2,5-dimethyl-2,4-hexadiene provides chiysanthemic acid, a natural product of the group of pyrethroic acids, used as an insecticide, see Figure 17.3 [3]. The appropriate esters of the 1R stereomers are the active compounds, which are obtained industrially by resolution of the racemates. 

In a recent study, chiral separations for pyrethroic acids, which are the chiral building blocks of synthetic pyrethroids and the primary metabolites of the acid part of these potent ester insecticides, have been developed [62], For example, a polar-organic mobile phase allowed the complete baseline resolution of all four stereoisomers of chrysanthemic acid (2,2-dimethyl-3-(2-methylprop-l-enyl)-cyclopropanecarboxylic acid) on a 0-9-(tcrt-butylcarbamoyl)quinine-based CSP(acjj = 1.20, oLtrans = 1-35, critical Rs = 3.03) (Figure 1,32a). This chiral acid is the precursor of pyrethroids like allethrin, phenothrin, resmethrin, and tetramethrin but not excreted as metabolite. The primary acid metabolite of these pyrethroids is chrysanthemum dicarboxylic acid (3-[(l )-2-carboxyprop-l-enyl]-2,2-dimethylcyclopropanecarboxylic acid) the stereoisomers of which could also be resolved with a reversed-phase eluent (acetonitrile— 30-mM ammonium acetate buffer 90 10, v/v pHa = 6.0) and employing an O-9-(2,6-diisopropylphenylcarbamoyl)quinine-based CSP ads = 1-09, atrans = 1-50,... 

Pyrethrum is an extract of dried chrysanthemum flowers. The extract contains about 50% active insecticidal ingredients known as pyrethrins. The ke-toalcoholic esters of chrysanthemic and pyrethroic acids are known as pyrethrins, cinerins, and jasmolins. These strongly lipophilic esters rapidly penetrate many insects and paralyze their nervous systems. Both crade pyrethrum... 

Bicker,W., Lammerhofer, M., Lindner,W. Direct high-performance liquid chromatographic method for enantioselective and diastereoselective determination of selected pyrethroic acids, J. Chromatogr. A, 2004,1035, 37-46. 

Pyrethrins, Active insecticidal constituents of pyrethrum flowers. Isoln Staudinger, Ruzicka, Heh. Chim. Acta 7, 177 (1924). Prepn by reconstitution from pyrethro-lone and chrysanthemic acid Elliott, Janes, Chem. A Ind. (London) 1969, 270. Structure CrOmbie et al. J. Chem. Soc. 1956, 3963 Godin et al, ibid. [Pg.1266]

HSI21190, 130214 CAS4638-92-0 (( )-trans-chrysan-Ihemic acid) 497-96-1 (pyreihric acid) 487-67-2 (pyrethro-lone 82) 22054-39-3 ((+)-jasmolone)J... 

---