Simazine [2-Chloro-4,6-bis(ethylamino)-s-triazine ] 
In feeding studies with rats and rabbits, dealkylation was observed 
(See Table 1) (133). 
Work with labeled simazine has shown that a wide variety of plants, 
resistant and nonresistant, metabolize this material (473, 477, 1286). 
Using ring-labeled simazine-cl4, it was found that field corn (Zea mays) 
produced little (about 22) Earog (347, 348, 477) whereas in sweet corn the 
rate of decomposition to E+*o;, was high (1188). 
Other studies have demonstrated the formation in plants of 2-hydroxy- 
4,6-bis(ethylamino)-s-triazine from simazine (253, 254, 270. 509, 593, 594, 
595, 606, 1024,. 1025:,. 1026, 1027, 028, 1165, 1240); This reaction .ocecurred 
in light or dark (1163). 
A cyclic hydroxamate was postulated as the responsible agent in the 
metabolism of triazines by plants and a mechanism was proposed. This was 
confirmed with the isolation of 2,4-dihydroxy-—/-methoxy-1,4-benzoxazin-3-one 
from Zea mays and the demonstration that it can convert simazine to its 
hydresy "analog. (250, 2534 603, 605. 655, G87, 124), Pasi). 
The tolerance of several species of Gramineae was studied. Hydroxy- 
simazine and several other unidentified metabolites were observed. Tolerance 
was not related to the ability of their excised roots to metabolize ona 
simazine; however, the content of benzoxazinone derivatives was directly 
related to the ability of excised roots to form hydroxysimazine and another 
minor metabolite. Roots not containing benzoxazinone derivatives did not 
form hydroxysimazine but other minor metabolites were detected (604). 
Studies have shown that many soil microorganisms metabolize simazine 
(436, 573, 574, 767, 769, 1030, 1172, 1188). One of the major metabolites 
has been identified as hydroxysimazine (614, 615). In some organisms, 
degradation proceeded via dealkylation, deamination, or both, and hydroxy- 
simazine was not an intermediate. A major metabolite has been identified 
as 2-chloro-4-amino-6-ethylamino~s-triazine (778). 
c!4_ring-labeled simazine was fed to Coix lacryma L. After ethanol 
extraction and fractionation on a cation exchange column, the radioactive 
metabolites were 2-hydroxy-4,6-diethylamino-s-triazine and 2-hydroxy-4,6- 
diamino-s-triazine (703). 
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