Metosulam 磺草唑胺

中文通用名称： 磺草唑胺
英文通用名称： metosulam （BSI,ISO,ANSI）
商品名称： Eclipse、Pronto、Sansac、Sinal、Uptake
试验代号： D E 511、X R D 511、X D E 511
化学名称： 2’ ,6 ’ -二氯-5,7-二甲氧基-3’ -甲基[1,2,4]三唑并[1,5-a]嘧啶- 2 -磺酰苯胺
2’ ,6 ’ -dichloro-5,7-dimethoxy-3’ -methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfona-nilide
CA主题索引名及CAS登录号：
N-(2,6-dichloro-3-methylphenyl)-5,7-dimethoxy[1,2,4]triazolo [1,5-a]pyrimidine-2-sulfonamide
[139528-85-1]

化学结构类型： 三唑并嘧啶磺酰胺类
理化性质： 纯品为灰白或棕色固体；熔点210~211.5℃；密度1.49(20℃)；蒸气压为4×10-13Pa(25℃)。分配系数 LogP＝0.9778；水中溶解度为(20℃，mg /l)：100 (pH 5.0)，700 (pH7.0)，5600(pH9.0)。
毒性： 大(小)鼠急性经口LD50：>5000mg/kg；兔急性经皮LD50：>2000mg/kg；大鼠急性吸入LC50(4小时)：>1.9mg/l。鹌鹑和野鸭急性经口LD50：>5000mg/kg。

制剂： 80％水分散颗粒剂。
作用机理： 乙酰乳酸合成酶(ALS)的抑制剂。对小麦安全是基于其快速代谢，生成无活性化合物。磺草唑胺可被杂草通过根部和茎叶快速吸收，而发挥作用。
适宜作物： 玉米、小麦、大麦、黑麦等
安全性： 在推荐剂量下使用对作物安全。
防除对象： 磺草唑胺主要用于防除大多数重要的阔叶杂草如猪殃殃、繁缕、藜、西风古、龙葵、蓼等。
使用方法： 磺草唑胺苗后用于小麦、大麦、黑麦田中大多数重要的阔叶杂草如猪殃殃、繁缕等，使用剂量为5~10克有效成分/公顷。苗前和苗后使用可防除玉米田中大多数重要的阔叶杂草如藜、西风古、龙葵、蓼等，使用剂量为20~30克有效成分/公顷。
合成方法：
以巯基三唑为起始原料，经氯磺化与苯胺反应、合环、氯化、甲氧基化即得目的物。反应式如下：

主要原料与中间体： 5-氨基-3-巯基-1,2,4-三唑、2,6-二氯-3-甲基苯胺(可由间氯苯胺氯化得到)
分析方法： HPLC
开发公司： 美国陶氏农业科学(Dow Agroscience)公司。

metosulam
Herbicide
HRAC B WSSA 2; triazolopyrimidine

NOMENCLATURE
Common name metosulam (BSI, pa E-ISO, ANSI); métosulame ((m) pa F-ISO)
IUPAC name 2',6'-dichloro-5,7-dimethoxy-3'-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonanilide
Chemical Abstracts name N-(2,6-dichloro-3-methylphenyl)-5,7-dimethoxy[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonamide
CAS RN [139528-85-1] Development codes XDE 511; DE 511; XRD 511 (all Dow)

PHYSICAL CHEMISTRY
Mol. wt. 418.3 M.f. C14H13Cl2N5O4S Form Cream to tan coloured powder. M.p. 210-211.5 ºC V.p. 4 ´ 10-10 mPa (20 ºC, Knudsen effusion) KOW logP = 0.9778 (distilled water), 2.12 (pH 5), 2.46 (pH 7), 3.08 (pH 9) (all at 20 ºC) S.g./density 1.49 (20 ºC) Solubility In water 200 (distilled water, pH 7.5), 100 (pH 5.0), 700 (pH 7.0), 5600 (pH 9.0) (all in mg/l, 20 ºC). In acetone, acetonitrile and dichloromethane >5.0 g/l; in n-octanol, hexane and toluene £0.2 g/l. Stability Under normal storage conditions, decomposes above m.p. Little photolytic instability (DT50 140 d - Xenon Arc); stable to hydrolysis across environmentally normal range. pKa 4.8

COMMERCIALISATION
History Herbicide reported by M. Snel et al., Meded. Fac. Landbouwwet. Rijksuniv. Gent, 1993, 58/32, 845. 'Sansac' (mixture with 2,4-D EHE) launched in Turkey in 1994. Manufacturers Dow AgroSciences

APPLICATIONS
Biochemistry Branched chain amino acid (leucine, isoleucine and valine) synthesis (ALS or AHAS) inhibitor. Selectivity in wheat is due to rapid metabolic deactivation. Mode of action Herbicide readily taken up by roots and foliage. Uses Post-emergence control of many important broad-leaved weeds (including Galium aparine, Stellaria media, and all members of the Brassicaceae) in wheat, barley and rye; and pre- or post-emergence control of many important broad-leaved weeds in maize (including Chenopodium spp., Amaranthus retroflexus, Solanum nigrum and Polygonum persicaria). Phytotoxicity Non-phytotoxic to crops for which use is recommended. Formulation types SC; SE; WG. Selected products: 'Sansac' (Turkey) (Dow AgroSciences, Bayer CropScience); 'Sinal' (Middle East/Africa) (Dow AgroSciences, Bayer CropScience)

OTHER PRODUCTS
'Eclipse' (Dow AgroSciences, Bayer CropScience); 'Tacco' (Dow AgroSciences, Bayer CropScience) mixtures: 'Barko' (+ atrazine) (Dow AgroSciences); 'Metto' (+ atrazine) (Dow AgroSciences, Bayer CropScience); 'Presto' (+ fluoroglycofen-ethyl) (Dow AgroSciences, Bayer CropScience); 'Sound' (+ 2,4-D) (Dow AgroSciences, Bayer CropScience); 'Diplôme' (+ flufenacet) (Bayer CropScience); 'Terano' (+ flufenacet) (Bayer CropScience) Discontinued products mixtures: 'EF1166' * (+ fluroxypyr) (Dow AgroSciences, Bayer)

ANALYSIS
An hplc procedure based on extractive methylation is available on request from Dow AgroSciences.

MAMMALIAN TOXICOLOGY
Oral Acute oral LD50 for rats and mice >5000 mg/kg. Skin and eye Acute percutaneous LD50 for rabbits >2000 mg/kg. Not a skin sensitiser (guinea pigs). Inhalation LC50 (4 h) for rats >1.9 mg/l. NOEL (2 y) for rats 5 mg/kg b.w. daily; (18 mo) for mice 1000 mg/kg b.w. daily. ADI 0.02 mg/kg b.w. Toxicity class WHO (a.i.) U

ECOTOXICOLOGY
Birds Acute oral LD50 for mallard ducks and bobwhite quail >2000 mg/kg. Fish LC50 (96 h) for rainbow trout, bluegill sunfish and fathead minnows >solubility limit of a.i. Daphnia LC50 (48 h) >solubility limit of a.i. Algae LC50 (72 h) for green algae 75 mg/l. Bees Not toxic to bees. LD50 (48 h) (oral) >50 mg/bee; (contact) >100 mg/bee. Worms LC50 (14 d) for earthworms >1000 ppm.

ENVIRONMENTAL FATE
Animals Metosulam is rapidly absorbed following oral administration (DT50 <1 h), extensively metabolised in rodents, much less in dogs, and excreted with metabolites 3-hydroxy (aliphatic oxidation) and 5-hydroxy (O-demethylation) in urine (DT50 54-60 h in rodents, 73 h in dogs). In vitro percutaneous absorption is very low in humans and rats (<1% of applied in 24 h). Plants Metosulam is poorly absorbed from foliar application to wheat (<5% of applied), so there is little residue accumulation. Metabolised by hydroxylation of the ring methyl, to give a 3-hydroxymethyl- metabolite and its glycoside; these are the only major products found besides the parent molecule. Soil/Environment Laboratory aerobic degradation DT50 averaged 6 d (4 soils) at 20 ºC and 40% moisture-holding capacity. Field DT50 in the 0-10 cm horizon has a mean value of 25 d. Metosulam degrades via the 5- and 7- hydroxy analogues to 5-amino-N-(2,6-dichloro-3-methylphenyl)-1H-1,2,4-triazole-3-sulfonamide and CO2. Mean Koc (9 soils) <500. Spring-treated lysimeters recorded no component >0.1 mg/l in percolate following two successive annual treatments at c. 25 g a.i./ha.