Diazinon structure

Turfgrass chemicals are by no means the only toxic hazard faced by average people, nor indeed the most unjust or egregiously unfair one, of course. Consider, for example, the disproportionately high exposure of inner city residents to propoxur, chlorpyrifos, diazinon, and permethrin used to treat the insects and pests that are an everyday part of life in poorly maintained structures, rented by absent and indifferent landlords. The use of such chemicals in lawn management is far less directly utilitarian than in inner city homes, however such urban residents face a health hazard where lawn managers face a mere nuisance, if that. 

Figure 1 Structures of chemical warfare agents (sarin and soman), simulants (dimethyl methylphosphonate and diisoproyl fluorophosphate), and pesticides (paratliion and diazinon).

Prepared by bulk polymerization, an MIP for the detection of dicrotophos based on the Eu3+ complex has recently been presented [58]. The authors used reversible addition fragmentation chain transfer (RAFT) polymerization followed by ring closing methathesis (RCM) to obtain the star MIP with arms made out of block copolymer. The star MIP containing Eu3+ exhibited strong fluorescence when excited at 338 nm with a very narrow emission peak (half width -10 nm) at 614 nm. This MIP was sensitive to dicrotophos in the range of 0-200 ppb, but showed saturation above this limit. Cross-reactivity of this MIP was evaluated with respect to structurally similar compounds dichlorvos, diazinon and dimethyl methylphosphonate. In these tests no optical response of the polymer was detected even at concentrations much higher than the initial concentration of dicrotophos (>1000 ppb). 

A simple cyclization of hydrazides of o-acetylenylbenzoic and acetylenylpyrazolecarboxylic acid 50 can lead to four different compounds, namely the five-membered A-aminolactams, six-membred iV-amino lactams, and six-mem-bered diazinones and diazepinones, but only the first three have been reported. The unexpected formation of bis(pyrazolo[4,3- 7][l,2]diazepinone 51 (R = 4-MeOC6H4) structure has been established by X-ray crystallography <2005TL4457> (Equation 4). 

Unfortunately, it is not possible to accurately predict rates of volatilization or project air concenpations based on vapor pressures. Even when ambient conditions, substtates and formulations are similar, emission rates for pesticides will depend on other factors such as the concenttation and molecular structure of the active ingredient. Jackson and Lewis (1981) compared emission rates from three kinds of pest conttol sttips in the same room under constant conditions of temperature (21 1 °C) and humidity (50 20 %) and found that room air concentta-tions over a period of 30d were much higher for diazinon than for chlorpyrifos, but similar to those for propoxur [2-(l-methylethoxy)phenylmethylcarbamate]. On Day 2 , room air levels were 0.76 pg/m for diazinon, 0.14 pg/m for chlorpyrifos and 0.79 pg/m for propoxur. After 30 d, the air concenttations were 1.21, 0.16 and 0.70 pg/m, respectively. The vapor pressure of diazinon is nearly 100 times higher than that of chlorpyrifos and nearly 1000 times lower than that of propoxur (4 x 10 kPa at 20 °C). 

The toxic effects of some pesticide mixtures are additive, particularly when their toxic mechanisms are identical. The additive effects of the organophosphates chlorpyrifos and diazanon were demonstrated in one study. T Another study found the s-triazine herbicides atrazine and cyanazine to show additive toxic effects. Not all mixtures of similar pesticides produce additive effects, however. In one study, mixtures of five organophos-phate pesticides (chlorpyrifos, diazinon, dimethoate, acephate, and malathion) were shown to produce greater than additive effects when administered to laboratory animals. Another article discusses nonsimple additive effects of pyrethroid mixtures. Despite the similarities in their chemical structure, pyrethroids act on multiple sites, and mixtures of these produce different toxic effects. 10 ... 

The structures below show the insecticide diazinon, its hydrolytic product, and ethirimol. Bupirimate and dimethirimol have very similar structures. 

OP insecticide with a structure similar to malathion, which is not a substrate for PON (Li et aL, 2000). As also predicted, PON mice showed a dramatically increased sensitivity to chiorpyrifos-oxon and diazoxon (Shih et ai., 1998 Li et ai, 2000). PONl mice showed an intermediate sensitivity to diazoxon toxicity (Li ef al, 2000). PONl null mice showed only a slight increase in sensitivity to the toxicity of chlorpyrifos and diazinon (Shih et a ., 1998 Li el al., 2000). The most surprising observation was that PONl null mice did not show an increased sensitivity to paraoxon, the substrate after which the enzyme was named, despite having no paraoxonase activity in plasma and liver (Li ei ai. 2000). 

Figure 1. Chemical structures of 2,4-D, diazinon, carbaryl, carbofuran, dioxacarb, bendiocarb, promecarb, and fenobucarb.

There is evidence that organophosphates may play a role in disrupting glial cell growth. It has been demonstrated that chlorpyrifos, chlorpyrifos-oxon and diazinon inhibit DNA synthesis in nerve cells, in vitro (18). Tlie effects were more pronounced in glial cells (C6) than in neuronal cells (Cl2). The disruption of DNA synthesis could, in turn, result in altered glial cell structure, with consequent changes in the properties of the blood-brain-barrier. However,... 

Lapinski, L., Nowak, M.J., Fulara, J., Les, A., and Adamowicz, L., Relation between structure and tautomerism in diazinones and diazinethiones an experimental matrix isolation and theoretical ab initio study, /. Phys. Chem., 96, 6250-6254, 1992. 

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