Specification :

Simetryn

Common name: simetryn; simetryne
IUPAC name: N2, N4-diethyl-6-methylthio-1, 3, 5-triazine-2, 4-diamine; 2, 4-bis( ethylamino) -6-methylthio-1, 3, 5-triazine
Chemical Abstracts name: N, N' -diethyl-6-( methylthio) -1, 3, 5-triazine-2, 4-diamine
CAS RN: [ 1014-70-6]

PHYSICAL CHEMISTRY
Mol. wt.: 213.3; M.f.: C8H15N5S; Form: Whitish crystals. M.p.: 82-83 º C; V.p.: 9.5x10-2 mPa ( 20 ° C) . KOW: logP = 2.6 ( calc., unionised) . Henry: 5.07x10-5 Pa m3 mol-1 ( calc.) S.g./ density: 1.02; Solubility: In water 400 mg/ l ( 20 ° C) . In methanol 380, acetone 400, toluene 300, n-hexane 4, n-octanol 160 ( all in g/ l, 20 ° C) . pKa: 4.0, weak base.

APPLICATIONS
Biochemistry: Photosynthetic electron transport inhibitor at the photosystem II receptor site.
Mode of action: Selective herbicide.
Uses: Used in combination with thiobencarb to control broad-leaved weeds in rice.
Formulation types: GR.

MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats 750-1195 mg/ kg.
Skin and eye: Acute percutaneous LD50 for rats > 3200 mg/ kg. Not a skin or eye irritant ( rabbits) .
NOEL: ( 2 y) for rats 1.2 mg/ kg daily ( 2.5 mg/ kg b.w.) , mice 56 mg/ kg daily, dogs 10.5 mg/ kg daily.
ADI: 0.025 mg/ kg b.w. ( provisional value) .
Toxicity class: WHO ( a.i.) III; EPA ( formulation) III
EC hazard: Xn; R22| N; R50, R53

ECOTOXICOLOGY
Fish: LC50 ( 96 h) for trout 7, guppy 5.2 ppm.
Algae: Toxic.
Bees: Non-toxic.

ENVIRONMENTAL FATE
Animals: DT50 in rats c. 10 h. Excreted in urine and faeces; two oxidative metabolic pathways.
Plants: Selectivity and metabolism of simetryn reviewed.