Formamidine insecticide

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. 

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. 

Compounds that alter insect behavior in other ways may also be useful e.g. chemicals that increase insect locomotor activity should enhance the uptake of pesticides from treated surfaces. Such compounds are already known among the formamidines insecticides and their relatives that stimulate octopamine receptors (12), and further research in this area of pest biochemistry could reveal other locomotor stimulators such as phosphodiesterase inhibitors. A... 

Plapp, F.W., Jr., Synergism of pyrethroid insecticides by formamidines against Heliothis pests of cotton, /. Econ. Entomol., 72, 667,1979. 

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... 

Self-condensation of the formamidine (368) in xylene with a catalytic quantity of 4-toluenesulphonic acid gave amitraz (369) Scheme 5.84.) [492]. Dimethyl carbamoyl chloride and ethyl trifluoroacetate are also catalysts for this reaction. A one-pot condensation of 2,4-dimethylaniline, triethyl orthoformate and methylformamide with or without zinc chloride was reported to give amitraz in high yield [493, 494]. The drug is used as an insecticide and acaricide particularly against several species of cattle ticks in South Africa [495, 496] and is very effective in the treatment of refractory Demodecosis canis (mange) in the dog [497]. 

Other insecticides. Relatively few other groups of insecticides have been developed. Therefore mention is made only of the dinitrophenols, bridged biphenyls and the formamidines. An example of the latter is Chlordimefon which is toxic by virtue of its effect on the insect s nervous system. 

A new organonitrogen insecticide, hf-(2,4-dimethyl-phenyl) ff -methyl-formamidine, was determined on silica gel G plates developed with benzene-cyclohexane-methanol (1 1 1) mobile phase. The compound was detected with bismuth hyponitrite and potassium iodide reagents (73a) (Table 4). 

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