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Pesticide profiles : Toxicity, environmental impact and fate - Chapter 8

Triazines và triazoles 8.1. Tổng quan về lớp và bối cảnh mô tả chung Các hợp chất triazine là thuốc diệt cỏ và hầu hết các hợp chất triazole là thuốc diệt nấm. Tuy nhiên, cấu trúc của các thuốc trừ sâu ở cả hai nhóm cũng tương tự như ở chỗ chúng bao gồm một cấu trúc vòng đơn với ba nguyên tử nitơ. Do đó, hai nhóm hợp chất được đối xử với nhau trong chương này. | chapter eight Triazines and triazoles 8.1. Class overview and general description Background The triazine compounds are herbicides and most of the triazole compounds are fungicides. However the structures of the pesticides in both groups are similar in that they consist of a single ring structure with three nitrogen atoms. Therefore these two compound groups are treated together in this chapter. Triazine compounds The triazine herbicides were discovered in 1954. The first compound in the group simazine was manufactured in 1958 1 . Triazine herbicides are among the most widely used herbicides in the U.S. 2 . This group of herbicides is represented by atrazine simazine cyanazine and other compounds listed in Table 8.1. The structures of all of the triazine herbicides have a six-member ring containing three nitrogen atoms and three carbon atoms as shown in Figure 8.1. Triazines can be symmetrical with alternating nitrogen and carbon atoms around the ring or asymmetrical with adjacent nitrogen atoms. No differences in toxicity or action appear to be linked to these structural differences. Triazole compounds Triazoles are similar to triazines because they also contain three nitrogen atoms in their ring structures though they have only two carbon atoms in the ring structure instead of three. Amitrole and triadimefon are commonly used triazoles. Different side chains groups of atoms that branch off the central ring structure determine the activity and potency of the compound. Amitrole a triazole was the catalyst for the addition of the Delaney clause to the Food Drug and Cosmetic Act. This clause states that the residues of any cancercausing agent are not allowed as additives in food 3 . Triazine and triazole usage Triazine usage Total 1987 U.S. crop application of the active ingredients of triazines was greater than 85 000 tons 4 . Atrazine is the most widely used triazine compound in the U.S. 2000 CRC Press LLC Table 8.1 Triazines and Triazoles Triazines Ametryn .