Triazines metabolism

Hodgson, R. H. Alteration of triazine metabolism by ozone, p. 28. In Weed Science Society of America Abstracts, 1970. 

Aromatic biguanides such as proguanil (181) have been found useful as antimalarial agents. Investigation of the metabolism of this class of drugs revealed that the active compound was in fact the triazine produced by oxidative cyclization onto the terminal alkyl group. The very rapid excretion of the active entity means that it cannot be used as such in therapy. Consequently, treatment usually consists in administration of either the metabolic precursor or, alternately, the triazine as some very insoluble salt to provide slow but continual release of drug. 

Strong LC, C Rosendahl, G Johnson, MJ Sadowsky, LP Wackett (2002) Arthrobacter aurescens TCI metabolizes diverse s-triazine ring compounds. Appl Environ Microbiol 68 5973-5980. 

Van Aken B, JM Yoon, CL Just, JL Schnoor (2004) Metabolism and mineralization of hexahydro-1,3, 5-trinitro-l,3,5-triazine inside poplar tissues (Populus deltoides x nigra DN-34). Environ Sci Technol 38 4572-4579. 

R.H. Shimabukuro, G.L. Lamoureux, D.S. Frear, and J.E. Bakke, in Metabolism of s-Triazines and Its Significance in Biological Systems, ed. A.S. Tahori, Pesticide Terminal Residues (Supplement to Pure and Applied Chemistry), Butterworth, London (1971). 

A study has been carried out on the determination of triazine and carbamate pesticides and metabolities in seawater by HPLC with photodiode-array detection [393]. 

Plant Chlorsulfuron is metabolized by plants to hydroxylated, nonphytotoxic compounds including 2-chloro-7V-(((4-methoxy-6-methyl-l,3,5-triazin-2-yl)amino)carbonyl)benzenesulfon-amide (Duke et al., 1991). Devine and Born (1985) and Peterson and Swisher (1985) reported that the uptake of chlorsulfuron in Canada thistle leaves ranged from 23 to 43% after 2 d. The uptake in roots is higher under slightly acidic conditions. Fredrickson and Shea (1986) reported 12% of C-chlorsulfuron was taken up in the roots at soil pH 5.9. 

Lamoureux, G.L., Shitnabukuro, R.H., Swanson, H.R., and Frear, D.S. Metabolism of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) in excised sorghum leaf sections, / Agric. Food Chem., 18(l) 81-86, 1970. 

When rats were administered atrazine in drinking water at 0.1, 0.2, or 0.5 g/1 for 1 or 3 weeks, they excreted as the principal metabolite 2 -chloro-4-ethylamino-6-amino-s-triazine. Atrazine and its metabolites have been shown to alter the activity of some testosterone-metabolizing enzymes in the rat pituitary and hypothalamus and to decrease hormone-receptor binding in the prostate. ... 

Alkylthiotriazines. In our laboratory we have studied the metabolic fate of 2-(4-ethylamino-6-methylthio- -triazin-2-ylamino)-2-methylpropionitrile (cyanatryn, 1, Fig. 1). This compound is a member of a class of herbicidal -triazines which also includes ametryne, prometryne and terbutryne. We were interested to note ( ) that two of the major metabolites of cyanatryn were the mercapturic acids 2-[A-ethylamino-6-(N-acetylcysteinyl)- -triazin-2-ylamino]-2-methylpropionitrTle (2.1) and its N-de-ethyl derivative (2.2) (Fig. 2). This pathway had not hitherto been reported for this class of compound. 

Triazines pose rather more of a problem, probably because the carbons are in an effectively oxidized state so that no metabolic energy is obtained by their metabolism. Very few pure cultures of microoiganisms are able to degrade triazines such as Atrazine, although some Pseudomonads are able to use the compound as sole source of nitrogen in the presence of citrate or other simple carbon substrates. The initial reactions seem to be the removal of the ethyl or isopropyl substituents on the ring (41), followed by complete mineralization of the triazine ring. 

Sulfotransferase activity is not restricted to minoxidil. The ability of other pyrimidine-, as well as pyridine-, triazine- and imidazole N-oxides to serve as substrates was investigated using soluble liver preparation and PAPS. The variety of structures studied indicated that heteroaromatic N-oxides are generally metabolized by sulfotransferases183. Presumably, all of the heterocycles tested were conjugated via their N-oxide oxygens. 

Botanists, physiologists, and chemists were able to develop sensitive methods for residue analysis (Delley et al., 1967). They also developed a clear understanding of the herbicidal mode of action and the metabolic pathway of. v-triazines in plants, soil, and animals (Kniisli et al., 1969). These early investigations were supported by cooperation from universities in the United States and Europe where scientists recognized that these compounds would be very important tools for worldwide agriculture and to manage weeds in noncropland. 

The metabolism of triazine herbicides in plants is very complex and involves a variety of biological reactions. The most active crops metabolically include com, cotton, soybean, sugarcane, and wheat. Less complex metabolic pathways have been observed in citrus and various fruit crops. 

The triazine herbicides can be divided into four different structural classes chlorotriazines, methylthiotriazines, methoxytriazines, and atypical or asymmetrical triazines. The chlorotriazine group includes atrazine, simazine, pro-pazine, terbuthylazine, and cyanazine. The methylthiotriazine group includes ametryn, prometryn, and terbutryn. The methoxytriazine group will include prometon and secbumeton. Hexazinone and metribuzin were chosen to represent the atypical triazine group. The plant metabolism of the most researched member of each triazine group will be discussed in detail to cover all major biological and chemical transformations reported in the literature. 

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