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. 2021 Apr 14:9:647472.
doi: 10.3389/fchem.2021.647472. eCollection 2021.

Synthesis Candidates Herbicide Through Optimization Quinclorac Containing 3-Methyl-1H-pyrazol-5-yl

Dingfeng Luo  1   2 , Haodong Bai  2 , Xiaomao Zhou  1   2 , Lamei Wu  2 , Chengjia Zhang  2 , Zhongchi Wu  2 , Zuren Li  1   2 , Lianyang Bai  1   2
Affiliations

Synthesis Candidates Herbicide Through Optimization Quinclorac Containing 3-Methyl-1H-pyrazol-5-yl

Dingfeng Luo et al. Front Chem. .

Abstract

To enhance quinclorac potency, twenty-five derivatives were synthesized containing 3-methyl-1H-pyrazol-5-yl by intermediate derivatization methods (IDMs). These compounds were confirmed by melting point (mp), 1HNMR, 13CNMR, and HRMS. The compound 1,3-dimethyl-1H-pyrazol-5-yl 3,7-dichloroquinoline-8-carboxylate (10a) was determined by X-ray diffraction. The activity of these compounds substituent on the phenyl was: electron-drawing group > neutral group > donor-drawing group, the results was like that of substituted benzyl group on pyrazole. The herbicidal activity assays showed that compounds 1-(2-fluorophenyl)-3-methyl-1H-pyrazol-5-yl 3,7-dichloroquinoline-8-carboxylate (8l, EC50 = 10.53 g/ha) and 10a (EC50 = 10.37 g/ha) had an excellent inhibition effect on barnyard grass in greenhouse experiment. Greenhouse safety experiment of rice exhibited almost no difference in plant height and fresh weight treated 10a at stage 1∼2-leaf of rice after 14 days but 8l had a detrimental effect. Two season field assays showed 10a herbicidal activity on barnyard grass at 150 g/ha as equal as 300 g/ha quinclorac in fields in 2019 and 2020. The study demonstrated that 10a could be further researched as a potential herbicide to control barnyard grass in fields.

Keywords: barnyard grass; field assay; herbicidal activity; intermediate derivatization methods (IDMs); quinclorac.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Design of the target compounds.
FIGURE 2
FIGURE 2
Crystal structure of compound 10a.
FIGURE 3
FIGURE 3
Synthesis route to target compounds 8a-n, 9a-i, and 10a-b.
FIGURE 4
FIGURE 4
The leaf chlorophyll a, b, and a + b contents at 2∼3 stages in barnyard grass seedling treated with quinclorac and compounds 8l and 10a during 0–9 days. Data are the mean + standard errors (SE).
FIGURE 5
FIGURE 5
Rice safety experiment in greenhouse-treated 375 g a.i./ha 8l and 10a after 14 days.
See this image and copyright information in PMC

References

    1. Belmar J., Alderete J., Zuñiga C., Jiménez C., Jiménez V., Núñez H., et al. (2001). Synthesis of 1-n-Alkyl-3-Methyl- and 1-n-Alkyl-3- Phenyl-5-Pyrazolones and formyl derivatives. Bol. Soc. Chil. Quím. 46, 459–470. 10.4067/S0366-16442001000400010 - DOI
    1. Burris E., Leonard B. R., Martin S. H., White C. A., Graves J. B., Shaw R., et al. (1994). Fipronil: evaluation of soil and foliar treatments for control of thrips, aphids, plant bugs and boll weevils. Proceedings 2, 838–844.
    1. Chen C. N., Lv L. L., Ji F. Q., Chen Q., Xu H., Niu C. W., et al. (2009). Design and synthesis of N-2,6-difluorophenyl-5-methoxyl-1,2,4-triazolo[1,5-a]-pyrimidine-2-sulfonamide as acetohydroxyacid synthase inhibitor. Bioorg. Med. Chem. 17, 3011–3017. 10.1016/j.bmc.2009.03.018 - DOI - PubMed
    1. Cole D., Pallett K., Rodgers M. (2000). Discovering new modes of action for herbicides and the impact of genomics. Pesti. Outlook 11, 223–229. 10.1039/b009272j - DOI
    1. Du S., Tian Z., Yang D., Li X., Li H., Jia C., et al. (2015). Synthesis, antifungal activity and structure-activity relationships of novel 3-(Difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid amides. Molecules 20, 8395–8408. 10.3390/molecules20058395 - DOI - PMC - PubMed

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