Shandong Gaorui Chemical Co., Ltd.
Add：Nanshan Industrial Park, Qilu Chemical Industrial Zone, Linyi District, Zibo City, Shandong Province
Latest trends in herbicidal new pyrazoles
In recent decades, a large number of reports have reported the biological activity of pyrazole derivatives, and new pyrazole pesticides have been commercialized. At present, pyrazole compounds have become one of the focuses of attention in the field of herbicide research. With the emergence of new herbicide-containing varieties containing pyrazole rings, people's research on the relationship between their structure and activity has become more and more in-depth. It is found that the structure of pyrazole ring-containing compounds has a certain relationship between structure and activity. In this paper, the commercial pyrazole herbicides were introduced and classified according to the structure of the compounds. The new pyrazole-based compounds with herbicidal activity were reviewed, and the development trend of the compounds was prospected.
1. Substituted arylpyrazole derivatives
When the substituted arylpyrazole derivative acts as a target protoporphyrinogen oxidase (PPO), and the PPO on the biosynthetic chain of the weed cell is inhibited, the cell is induced to be destroyed, hindering protein synthesis and inhibiting cell growth. . In 1993, the Japanese pesticide company and the French Rohm and Haas company jointly developed the pyraflufen-ethyl (test code ET751, trade name "Acacia") (1), which can prevent pigs and leek from corn and wheat fields. Broadcasting of Artemisia scoparia, Ono sesame and other broadleaf weeds; in 1994, fluazolate (2) developed by BASF and Monsanto, USA, is mainly used to control broadleaf weeds in winter wheat fields. Pork chop, etc., used at a dose of 125-175 g/hm2, and the soil is blocked. The synthesis is carried out with o-chloro-fluorotoluene as raw material. The intermediate pyrazole is prepared through a series of reactions, followed by methylation and chlorination. The reaction produces a benzoic acid containing a pyrazole ring, and finally the product is obtained in three steps. The pyripramine (3) developed by BASF is also a protoporphyrinogen oxidase inhibitor.
In 1990, Compound 4 was developed by Nissan Chemical Co., Ltd., and can completely control valerian at a dose of 0.313 g/hm2. Sumitomo Chemical further summarized the structure-activity relationship of the synthesized substituted arylpyrazoles. 5 can remove broadleaf weeds such as Castanopsis chinensis at a dose of 37.5 g/hm2; 4-formylpyrazole compounds are new structures reported in recent years. The target of this variety has been reported to be p-hydroxyphenylpyruvate. Double oxidase (HPPD), after absorption by plant leaves, catalyzes the conversion of hydroxyphenylpyruvate to urinary acid, which indirectly affects the synthesis of carotene, resulting in a disorder in the synthesis of chlorophyll. Commercially available varieties of such compounds, such as Japan Sankyo Co., have developed a pyrazole-based herbicide pyrazylate (6) containing benzoyl and benzopyrazone (7) developed by BASF, under the trade name " "Defense", used as a herbicide in corn fields, has a wide spectrum of herbicides, and is safe for corn. At present, the registration of the original drugs and preparations has been obtained in China.
Structural derivatization based on the above two varieties is a research hotspot in recent years, mainly focusing on the transformation of benzoyl and substituted pyrazolyl. In the benzoyl modification, for example, Ahrens et al. introduced a thio group into benzoyl group, and designed and synthesized compound 8, which has good herbicidal activity. At the application dose of 80g/hm2, it is suitable for valerian and yarrow The herbicidal activity reached 90%.
Compound 9 synthesized by Japan's Ishihara Industry Co., Ltd. has a control effect on crabgrass and valerian at a dose of 7 g/hm2 higher than 90% and is safe for wheat.
Heinemann replaces the thio group with an amino group in the same position as the benzoyl group, and synthesizes a series of benzoylpyrazoles. The bioactivity test results show that the compound 10 is at a dose of 80 g/hm2 for Persian, The herbicidal activities of Thousands of Gold, Valerian, and foxtail were 90%. When Compound 11 was 320 g/hm2, the herbicidal activities against Persian and Nasal were 90% and 100%, respectively. Wen Yanpeng et al. introduced a methylsulfonyl group at the 4-position of benzoyl group from a commercial variety of sulcotrione, and the novel benzoylpyrazole compound 12 was synthesized at a dose of 150 g/hm2. The inhibition rate of the grass is 100%.
In the direction of the replacement of the pyrazolyl two parts, Qingdao Qingyuan Agricultural Crown Co., Ltd. has launched new varieties such as cycloflufenone in recent years. The research indicates that its target is HPPD enzyme, which is expected to be listed this year. The company synthesized a series of benzoylpyrazole compounds, and the activity test results showed that compound 13 at the dose of 150 g / hm2, broadleaf on the seedlings, amaranth, maijiagong, piglet, yarrow The growth inhibition rate of weeds is higher than 90%. Compound 14 has a growth inhibition rate of ricin, wild rapeseed, Maijiagong, valerian, and Qianjin at a dose of 50 g/hm2, which is higher than 90% for corn and wheat, but for the growth of bluegrass and wheat. The inhibition rate is less than 5%.
Witschel et al. retained the isoxazoline group of benzopyrazone, and the synthesized compound 15 had a growth inhibition rate of 100% for both alfalfa and valerian at a dose of 62.5 g/hm2. Compound 16 developed by Nissan Chemical Co., Ltd. can completely prevent crabgrass, valerian and foxtail in the pre-emergence at a dose of 6.3 g/hm2. The inhibition rate of Compound 17 on the very low dose of 2.52 g/hm2 against the ragweed, valerian and sedge was higher than 90%.