Imazethapyr

Chemical Properties

Pure product: colorless crystals, no odor. m. p. 169-174 °C, vapor pressure: being less than 0.013 x 10-3 Pa (60 °C). Solubility at 25 ℃: Methanol 105g / L, Isopropyl alcohol 17g / L, Toluene 5g / L, Heptane 0.9g / L, Water 1.4g / L. Corrosive.

Herbicide

Imazethapyr is an organic heterocyclic herbicide which belongs to the class of imidazolinones.
Its isopropylamine salt is suitable for the control of all kinds of weed, having excellent herbicidal activity on sedge weeds, annual and perennial monocotyledonous weeds, broad-leaved weeds and miscellaneous wood. It can be used before or after buds, can be quickly absorbed by plant roots and leaves, being capable of inhibiting the biosynthesis of plant side chain amino acids (valine, leucine, and isoleucine), destroying the protein so that the growth of weeds is suppressed and weeds will finally die. Sensitive weeds immediately stop growing after foliar treatment, usually at 2 to 4 weeks after death. Selectivity is due to the different metabolic rate of plants, resistant plants metabolize faster than sensitive plants. Leguminous plants, after absorbance of Putex special, will quickly metabolize it. It is safe to soybean. Imazethapyr, inside the soybean body, has a half-life of about 1.6 days. In the dosage of above 100g active ingredient / hm2, it will have significant inhibitory effect on the soybean during initial stage of application, but the plant can quickly recover.
Be caution when used in low-lying fields and acid soil. The drug has a long residual period in the soil. Any sensitive crops such as Chinese cabbage, rape, cucumber, potato, eggplant, pepper, tomato, beet, watermelon and sorghum can not be planted within three years after application of imazethapyr. However, according to the recommended dose, the later crop can be spring wheat, soybeans or corn. In multiple cropping per year area of our country, it is even more important to choose rotated crop according to the specific circumstances.
Synthesis and screening of imidazolinones began in 1975, M. Los and others first reported such herbicides in 1982. In 1983, PLOrwick et al. reported that imazapyr and its imazapyr-isopropylammonium. Meanwhile, DL Shaner et al. reported imazaquin and its imazam-ammonium, making imidazolinone compounds an active area for the development of new herbicides. Then D. L. Shaner and N.E. Shafer reported the herbicidal activity of imazamethabez-methyl, and T. Malefyt et al reported the herbicidal activity of imazethapyr and its imazethapyr-ammonium.

Application

It belongs to imidazolinones selective pre-emergence and post-emergence herbicides, being the branched-chain amino acid synthesis inhibitors. It is absorbed through the roots and leaves and conducts in the xylem and phloem and accumulates in the plant meristem, affecting the biosynthesis of valine, leucine and isoleucine, destroying the protein and killing the plant. Pre-mixing it with soil for treatment before sowing, applying soil surface treatment before emergence and early post-emergence application can control many grasses and broad-leaved weeds. Soybean has resistance; the general amount is 140 ~ 280g / hm2; it has also been reported of using 75 ~ 100g / hm2 in soybean field for soil treatment. It is also selective for other legume at a dosage of 36 ~ 140g / hm2. If using a dose of 36 ~ 142 g/ hm2, either mixing with soil or early post-emergence spraying, can effectively control two-color sorghum, westerly, amaranth, mandala and so on; the dose of 100 ~ 125g / hm2, when mixed with soil or pre-treated before emergence, have excellent control effect on the barnyard grass, millet, setaria viridis, hemp, amaranthus retroflexus and goosefoots. Post-treatment can control annual grass weeds and broad-leaved weeds with the required dose of 200 ~ 250g / hm2.
Selectively pre-emergence and early post-emergence soybean crop herbicide, which can effectively prevent the amaranth, Polygonum, Abutilonum, Solanum, Xanthium, Setaria, Crabgrass and other weeds.

Preparation

• Diketene is treated with chlorine in the dichloromethane to extract the chloroacetic acid ethyl ester. The compound is reacted with methylene chloride at room temperature for 10 hours to give 2, 4-dichloroacetoacetate. Reflux 2-ethylacrolein and ammonium sulfamate in absolute ethanol for 1.5 hours to give ethyl 2-chloromethyl-ethyl nicotinate, which is further reacted with 2-amino-2,3-bis Methyl butyramide and sodium bicarbonate in dimethyl sulfoxide at 80 ℃ for 6h, the resulting condensation product was hydrolyzed and then cyclized in acetic acid to produce imazethapyr.
• 2, 3-pyridinedicarboxylic acid is reacted with acetic anhydride in toluene to produce pyridine dianhydride, which is then reacted with (CH3) 2CHCOH3 (CN) NH2 at 10-12 ° C to form carbamoyl nicotinic acid. Apply hydrogen peroxide in sodium hydroxide solution for hydrolysis, and finally heat to 70 ℃ for cyclization reaction, that is, imazapyr.

Category

Pesticides

Toxicity classification

low toxicity

Acute Toxicity

Oral - Rat LD50: 5000 mg / kg; Oral - Mouse LD50: 5000 mg / kg.

Flammability Hazard Characteristics

Combustion produces toxic nitrogen oxides

Storage and transportation

warehouse ventilated, low temperature, and dry; separate it from food raw materials for transportation.

Extinguishing agent

dry powder, foam, sand

Uses

Imazethapyr is a herbicide that that is used in biological studies to evaluate the effect on non-target vegetation within agroecosystems.

Definition

ChEBI: Imazethapyr is an aromatic carboxylic acid and a member of pyridines.

Mechanism of action

Systemic with contact and residual activity. Inhibits plant amino acid synthesis - acetohydroxyacid synthase AHAS.

Pesticide Type

Herbicide