Biological activities acaricidal

Unsaturated 5(4//)-oxazolones have also been used as intermediates to prepare analogues with diverse biological activities. For example, the oxazolone derived from 4-biphenylcarboxaldehyde is a synthetic precursor of the antiinflammatory agent 4-biphenylacetic acid." In addition, 2-substituted oxazolones derived from 2-thioarylbenzaldehydes are starting materials for the preparation of dibenzothie-pine derivatives that are useful to treat schizophrenia." Other oxazolones have been used as intermediates to prepare insecticides and acaricides." ... 

Aliphatic Hydrocarbons. After extensive research into the biological activity of the aliphatic hydrocarbons, relatively few of the pure Inonderivativel compounds have been found worthy of commercial attention. Popular for use in orchard spraying are the petroleum derivative oil spray s, which possess a good combination of acaricidal and insecticidal activity wiih low phytoioxicity. These sprays are effective against San Jose scale and mite. 

Carbodiimides can be used as stabilizers in thiophosphate based pesticides to prevent hydrolytic degradation. Some carbodiimides show insecticidal and acaricidal properties. Diafenthiuron [l-t-butyl-3-(2,6-diisopropyl-4-phenoxyphenyl)thiourea], an effective insecticide and acaricide, may act via its derived carbodiimide. This transformation is accomplished by sunlight degradation in aqueous solution. The carbodiimide causes inhibition of ATP phosphorylation. An H-labeled derivative of diafenthiuron, [phenoxy-4- H]diafenthiuron, has been prepared to study its photochemical and metabolic degradation. " The biological activity of N-(pyrid-3-yl)thioureas toward spider mites is sensitive to the kinetics of the formation of the carbodiimides and their photochemical stability. ... 

Several sulfoxides and sulfones are biologically active examples include diaryl sulfones, e.g. dapson (89) (Figure 3). This is an antibacterial agent because it acts as a PABA antagonist like the sulfonamide drugs (see Chapter 11, p. 223). Other diaryl sulfones, e.g. tetradifon (90), are used as acaricides to control spider mites on plants. 

Sulfonyl chlorides (51) are used in the manufacture of many biologically active compounds like the sulfonamide antibacterial drugs (see Chapter 2, p. 25 and Chapter 11, pp. 222-6) and pesticides such as the acaricide tetradifon (60) (see Chapter 11, p. 235), which is synthesised from 1,2,4-trichlorobenzene (61) (Scheme 36). 

A wide variety of organosulfur compounds show useful biological activity examples include the sulfonamide antibacterials and diuretics, penicillin and cephalosporin antibiotics, the antiulcer drug ranitidine, and agrochemicals such as the thiophosphoryl (P=S) insecticides like malathion, herbicides like chlorsulfuron, many fungicides like the dithiocarbamates (see Chapter 9, p. 148) and captan (see Chapter 9, p. 151), and sulfone acaricides like tetradifon (see Chapter 7, p. 104). 

Chemical and biological activity studies of P. erosus seeds started since 1890 with M. Gresshoff, leading forty years later to the identification of rotenone (32) as the insecticide, acaricidal and fish poison [61]. At the present time, at least twenty isoflavonoids, mainly rotenoids "Fig. (10) have been isolated from this source (Table 4). 

Unlike the MET-I acaricides and insecticides, the MET-III inhibitor acequinocyl is a pro-insecticide that requires biological activation for activity. Acequinocyl is hydrolyzed to the corresponding deacyl derivative, 2-hydroxy-3-n-dodecyl-l,4-naphthoquinone (DHN), in isolated mitochondria (Fig. 28.3.3) [76]. This is consistent with the observation of a time lag in MET inhibition with acequinocyl [76] and that acequinocyl itself does not directly inhibit MET activity [91]. 

Numerous derivatives of (30) have been prepared and shown to display a wide spectrum of biological activity, e.g. acaricidal, sedative," etc. Further examples may be found in the patent literature. 

BiPy and 1,10-phenanthroline (I7). (h) Biological activity as acaricide against Tetranychus species r ... 

Of this biologically very effective group, the carbonic acid derivatives of 2,3-dithioquinoxaline have proved to be the most active (Sasse et al.. 1960). The active compounds first became known as excellent acaricides (Unterstenhdfer, 1960 Sasse, 1960) because they were also effective against acarus species resistant to phosphoric compounds. At the same time, they have the valuable property of being toxic to powdery mildew fungi. 

The discovery, synthesis, structure-activity relationship and biology of this new class of carbazate acaricides and bifenazate is described in this chapter. 

Pesticides are chemicals or biological substances used to kill or control pests. They fall into three major classes insecticides, fungicides, and herbicides. Others classes are rodenticides, nematicides, molluscicides, and acaricides. These chemicals can be natural compounds or synthetic ones. Pesticides may also be divided into contact and systemic pesticides. Pesticides that were earlier produced were of the contact type. They do not appreciably penetrate plant tissue, so they are susceptible to the effects of the weather and moreover new plant growth is not protected. Vice versa, most of the recently developed pesticides are systemically active. They move through the plant vascular system and thus they not only can protect a plant from attack but also inhibit or cure established infections. Systemic pesticides are not affected by weathering and also confer immunity to all new plant growth. In 1993, 57% of all the pesticides used in the United States were herbicides, while 23% and 12% were insecticides and fungicides, respectively [1]. 

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