Insecticides chlordimeform

Leslie, C., Reidy, G.F., Murray, M. Stacey, N.H. (1988) Induction of xenobiotic biotransfor-mationby the insecticide chlordimeform, a metabolite 4-chloro-o-toluidine and a stracturally related chemical o-toluidine. Biochem. Pharmacol, 37, 2529-2535 Lewis, R.J., Jr (1993) Hawley s Condensed Chemical Dictionary, 12th Ed., New York, Van Nostrand Reinhold, p. 55... 

Formamidines comprise a small group of promising insecticides. Chlordimeform, formetanate, and amitraz are examples of this group. These compounds are effective against most stages of mites and ticks. Thus they am classified as ovicides, insecticides, and acariddes. Formulations are emulsifi-able concentrates and water-soluble powders. 

The formamidine acaricides and insecticides, chlordimeform and ami-traz, are lethal to all life stages of acarines, but their activity to insects is considerably more restricted (1). Using the southern cattle tick, Boophilus microplus, and the twospotted spider mite, Tetranychus urticae, the structural requirements of formamidines for lethality have been elucidated ( -5), an< t ie structure (lethal moiety) for maximum activity is shown in Figure 1. Briefly, the ring must contain two substituents, and they must be located at positions two and four maximum activity was observed when position... 

Needless to say, it would be interesting to apply the same type of chemistry described in Figure 2 for the methylcarbamate esters to the synthesis of derivatives of the formamidine insecticides. However, additional work with the formamidines, particularly those related to chlordimeform, has been discouraged because of the mutagenic and carcinogenic potential of the aryla-mine metabolic products. 

Chloro-ort/2o-toluidine and its hydrochloride salt were produced commercially in substantial amounts as intermediates in the manufacture of azo dyes and chlordimeform, an insecticide. Since the 1980s, production and use of 4-chloro-ort/20-toluidine have been discontinued in most countries. 

Import, export, manufacture, and possession of hazardous substances have been controlled under the Hazardous Substances Act, 1992. However, banning of the import or severely restricted uses of chemicals had been notified in the Ministerial Notifications since 1977. Two insecticides, namely chlordimeform and leptophos were the first two of the banned chemicals in 1977. According to the Act, Ministerial Notifications of the Ministry of Industry were issued to harming of nine specified POPs pesticides usage since 1980 (Table 10.4). Only seven specified POPs pesticides were imported and widely used in Thailand, namely aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, and toxaphene, whereas hexachlorobenzene and mirex have never been imported. Although... 

Formamidine insecticides are all derivatives of formamidine (HN=CHNH,). This class comprises a new, small group of chemicals that exhibit insecticidal and miticidal properties. Three examples are chlordimeform, formetanate hydrochloride, and amitraz, shown as follows. 

This section will discuss insecticides, acaricides, and repellents having toxicological characteristics distinct from the insecticides discussed in the previous section. It discusses pyrethroids, fluorides, borates, chlordimeform, propargite, substituted haloaromatic urea compounds, chlorobenzilate, cyhexa-tin, methoprene, sulfur, diethyltoluamide, aUcyl phthalates, and benzyl benzoate. 

Some older compounds such as toxaphene, lindane and cyclodiene insecticides have been around for some time without their mode of action being known. My third observation is that, almost as a tradition, some insecticidal activity has been found and then later a physiological lesion has been discovered. The initial acaricidal activity of chlordimeform, the nematicidal activity of avermectin, or the diptericidal activity of cyromazine are good examples. 

According to recent estimates, some 35 chemical pesticides are currently used to control various pests on cotton (1). There is considerable variation across the USA cotton belt in seasonal pesticide application rates, ranging from a high average of 7.4 pounds per harvested acre in Florida to a low of 0.3 in Oklahoma. Currently, methyl parathion (21.0%), azinphosmethyl (13.0%), various pyrethroids (8.0%), chlordimeform (7.4%), propargite (6.8%), and aldicarb (6.8%) account for 63% of all insecticides applied to cotton (1). 

With these principles in mind, it has proved profitable sometimes to replace carbon by nitrogen as in the highly successful insecticide that has been made from octopamine (2.55), an important neurotransmitter in insects. Here — N CH— was substituted for the —CH(OH)—CH2-group, creating a new series of insecticides of which chlordimeform 2.36) was the best. It gives the insect an overdose of agonistic activity (Evans and Gee, 1980). 

Chlordimeform (2,36) was introduced in the early 1970s to control mites, ticks, and moths in the field. Chemically it is iV-(2-methyl-4-chlorophenyl)A iV -dimethylformamidine, and it has shown no cross-resistance with other insecticides. Its selectivity is attributed to its mimicry of octopamine 2.35), which is an important neurotransmitter in arthropods but not in vertebrates (Evans and Gee, 1980). Death occurs partly by exhaustion after overstimulation, partly by starvation. The only effect on mammals appears to be an inhibition of monoamine oxidase, 300 times weaker than that evoked by the much-used anti-depressant drug, tranylcypromine (9.47) (Aziz and Knowles, 1973). The suggestion that inhibition of this enzyme also contributes to the effect on insects and mites is not tenable (Neumann and Voss, 1977). 

Chlordimeform (2.3 ), a much used insecticide which gently inhibits mammalian MAO, seems to owe its usefulness in the field to mimicry of the arthropod neurotransmitter, octopamine 2.35) (see Sections 2.6.1 and 6.4.1). 

Polymeric insecticides containing benzoin- or ethyleneglycol carbamate via hydro-lysable or fight-sensitive spacer groups, or containing chlordimeform bound as a salt... 

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