Alpha Cyano pyrethroids

Brooks, M.W. and J.M. Clark. 1987. Enhancement of norepinephrine release from rat brain synaptosomes by alpha cyano pyrethroids. Pestic. Biochem. Physiol. 28 127-139. 

Meacham CA, Brodfuehrer PD, Watkins JA, Shafer TJ (2008) Developmentally-regulated sodium channel subunits are differentially sensitive to alpha-cyano containing pyrethroids. Toxicol Appl Pharmacol 231 273-281... 

Pyrethroids may conveniently be classified into two groups based on the chemical structure and toxic action (1 -Z8). Type I pyrethroids do not possess an alpha-cyano group and include many conventional ones such as allethrin, tetramethrin, phenothrin and permethrin. Type II pyrethroids possess a cyano group at the a position and include cyphenothrin, cypermethrin, deltamethrin and fenvalerate. 

The development of fenvalerate and later esfenvalerate led to the synthesis and commercial marketing of fluvafinate, which is active against spider mites (Hemick et al. 1980). Fuchs synthesized aU of the seven possible fluoro-substituted isomers of cypermethrin (e.g., 2,4,5,6,2, 3 and 4 ) (Hamman and Fuchs 1981). Substitution at the 4 -position produced the most active compound, cyfluthrin. Activity was almost eliminated when chlorine was substituted for fluorine in the 4 -position. Tefluthrin has a higher vapor pressure than most of the other pyrethroids and is active against soil pests such as the com root worm (Jutsum et al. 1986). Bifenthrin is an ester with alcoholic compruients whose activity is not enhanced by an alpha-cyano substituent. Bifenthrin is active against insects (aphids) and mites (Plummer et al. 1983). 

Pyrethrolds are synthetic insecticides that resemble pyrethrins in structure and action, a. Type 1 pyrethroids do not contain an alpha-cyano moiety, b Type 2 pyrethroids contain an alpha-cya> o moiety. 

The pesticides included in this study were fenvalerate, chlordecone (kepone), chlorothalonil, and chlorpyrifos. Fenvalerate is a synthetic pyrethroid insecticide used, for example, for mites on chickens. Its chemical name is cyano(3-phenoxyphenyl)-methyl 4-chloro-alpha-(1-methylethyl)benzeneacetate. Chlordecone is an insecticide, no longer used, and has a chemical name decachloro-octahydro-l,3,4-metheno-2H-cyclobuta(cd)=pentalen-2-one. Chlorothalonil is fungicide used on tomatoes whose chemical name is 2,4,5,6-tetrachloroisophthalonitrile. Chlorpyrifos is an insecticide with a chemical name 0,0-diethyl 0-(3,5,6-trichloro-2-pyridyl)phosphorothioate. Chlorpyrifos is the U. S. Food and Drug Administration chromatographic reference standard since numerous specific detectors (electron capture, flame photometric in both sulfur and phosphorus modes, alkali flame, nitrogen phosphorus, and Hall detectors) are sensitive to it. 

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