Insecticidal compounds

Chlorinated Terpenes. A group of incompletely characterized insecticidal compounds has been produced by the chlorination of the naturally occurring terpenes. Toxaphene [8001-35-2] is prepared by the chlorination of the bicycHc terpene, camphene [79-92-5] to contain 67—69% chlorine and has the empirical formula C QH QClg. The technical product is a yellowish, semicrystalline gum (mp 65—90°C, d 1.64) and is a mixture of 175 polychloro... 

It would seem obvious that efforts should be concentrated on following up the many leading observations which have been reported and determining the structure of the substances already isolated. However, re-examination of the biology and chemistry of species which have yielded insecticidal compounds in the past certainly should not be overlooked. Dr. Beckman will show that careful investigation of such a well-known commercial preparation as pyre-thrum extract can reveal the presence of unsuspected and active new constituents Dr. Moore will indicate how some such observations may be turned to profit through synthesis of simple analogs. 

Bowman BT, Sans WW. 1983. Further water solubility determination of insecticidal compounds. J Environ Sci Health B 18 221-227. 

Marr, K. L. and Tang, C. S. 1992. Volatile insecticidal compounds and chemical variability of Hawaiian Zanthoxylum (Rutaceae) species. Biochem. Syst. Ecol. 20 209-217. 

There is nothing basically new in our present problem, but there are a great variety of new insecticidal compounds and formulations available, and there is a greatly increased demand for their use. 

Another extremely important military requirement that is not usually associated with civilian requirements is stability in prolonged storage under adverse conditions. For example, the first lots of fly spray that were shipped to North Africa, in 1942, contained pyrethrum as the principal active ingredient. It was not possible to store this material under cover and much of it remained under constant exposure to the intense tropical sun, undoubtedly deteriorating very rapidly. Covered storage facilities are the exception rather than the rule in a combat theater of operations, and all insecticide compounds furnished to the military forces should withstand this type of storage. 

Schlinke, J.C., J.S. Palmer, and L. Hunt. 1969. Preliminary toxicologic study of a phosphorothioate insecticidal compound in turkeys. Amer. Jour. Vet. Res. 30 1705-1709. 

In the first year, the maximum concentrations of sulfoxide and sulfone in soil, seed potatoes, and foliage were approximately 2, 2, and 6 times, respectively, the concentrations of those metabolites measured in the second and third year treatments. These results demonstrated that enhanced microbial degradation of relatively minor insecticidal compounds in the soil can significantly affect insecticide levels in the plant (when these degradation products are the major insecticidal component accumulated). As the sulfoxide and the sulfone metabolites are the major toxicants in the foliage of potato plants grown in disulfoton-treated soil, this reduction in toxicant residues overtime can be expected to reduce insecticide efficacy. 

Bowman, B.T. and Sans, W.W. Further water solubility determininations of insecticidal compounds, J. Environ. Sol. Health, B18(2) 221-227, 1983. 

Fig. 11. Some insecticidal compounds from Asteraceae and Apiaceae.

Fig. 13. Insecticidal compounds from the Piperaceae and the general structure of natural and synthetic insecticidal alkyl furans.

Rodriguez-Saona C, Millar JG, Maynard DF,Trumble JT, Novel anttfeedant and insecticidal compounds from avocado idioblast cell oil,/ Chem Ecol24 867—889,... 

It Is well known that phosphorothlonate insecticides such as parathlon (, 0-diethyl p-nitrophenyl phosphorothloate) and malathion [0, -dimethyl -(l,2 -dlcarbethoxy)ethyl phosphoro-dithioate] are Intrinsically poor inhibitors of acetylcholinesterase and in vivo activation to the respective anticholinesterases paraoxon and malaoxon is required before animals exposed to the phosphorothionates are intoxicated. Since metabolic activation is essential to the biological activity of these thiono sulfur-containing organophosphorus insecticides, compounds of this type may be considered as propesticides or, more specifically, prolnsectlcldes. 

Several nerve toxins produced by plants are interesting because of their insecticidal properties. Insecticidal nicotine is extracted from tobacco. Rotenone (Figure 19.2) is synthesized by almost 70 legumes. This insecticidal compound is safe for most mammals, with the notable exception of swine. The most significant insecticidal plant derivatives, however, are the pyrethrins, discussed below. 

One compound may be toxic when used alone, and another may not. If a combination of the two is more toxic than the insecticidal compound alone, synergism is said to occur, and the nontoxic compound is the synergist. Several important synergists that can increase the toxicity of insecticides contain the active moiety methylendioxyphenyl (MDP) ... 

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