Synthesis and Herbicidal Activities of Novel Substituted Acetophenone Oxime Esters of Pyrithiobac

Abstract

A series of substituted acetophenone oxime esters of Pyrithiobac were synthesized as potential herbicides. The structures of the synthesized new compounds were confirmed by 1H NMR, 13C NMR, HRMS, and X‐ray single‐crystal diffraction (XRD). The pre‐emergence and post‐emergence herbicidal activity studies show that 4‐CF3 (6 f), 4‐NO2 (6 i), 4‐NH2 (6 j), 4‐F (6 l), and 2,4‐2OCH3 (6 s) substituted acetophenone oxime esters of Pyrithiobac exhibit better pre‐emergence and post‐emergence herbicidal activities against monocotyledon and dicotyledon weeds than other synthesized new compounds. In pre‐emergence herbicidal activity study, 6 f, 6 i, 6 j, 6 l, and 6 s exhibit similar herbicidal activities against monocotyledon and dicotyledon weeds as compared to Staple (Pyrithiobac‐sodium). In post‐emergence herbicidal activity study, 6 f, 6 i, 6 j, 6 l, and 6 s exhibit similar herbicidal activities against dicotyledon weeds and better herbicidal activities against monocotyledon weeds as compared to Staple. Compounds 6 i and 6 l with high herbicidal activities and similar binding mode with acetolactate synthase as compared to Staple were further subjected to crop safety study. The results show that the safety of compound 6 l to cotton is as good as Staple and better than 6 i. The present work indicates that compound 6 l may serve as a new candidate for potential herbicides.

Design, Synthesis, and Herbicidal Activity of Diphenyl Ether Derivatives Containing a Five-Membered Heterocycle

“…Pyribenzoxim is a benzophenone oxime ester derivative of bispyribac-sodium. Its herbicidal activity is enhanced compared with bispyribac-sodium. , …”

“…27 For example, thenylchlor is an herbicide containing a thiophene moiety that is effective against a wide range of weeds in rice, soybean, and other crop fields. In addition, the oxime ester moiety was reported to possess diverse biological activities, 28 such as antiinflammatory, 29 antifungal, 30,31 antioxidant, 32 insecticidal, 33 acaricidal, 34 and herbicidal properties. 35 Pyribenzoxim is a benzophenone oxime ester derivative of bispyribac-sodium.…”

“…Its herbicidal activity is enhanced compared with bispyribacsodium. 28,36 First, bioisosterism design is very important in the search for bioactive materials, and it has been continuously used in the development of novel herbicides. 37 In addition, substructure splicing is a common means for inventing new drugs.…”

Oxime‐Derived Iminyl Radicals in Selective Processes of Hydrogen Atom Transfer and Addition to Carbon‐Carbon π‐Bonds

“…Oximes are a fundamental class of organic compounds that is widely used in organic synthesis. Their Osubstituted derivatives (oxime ethers or esters) exhibit diverse biological activities, such as antibacterial, [1][2][3][4] anti-cancer, [5,6] anti-inflammatory, [7,8] antimycotic, [9][10][11] antifungal, [12][13][14][15][16][17] herbicidal, [18][19][20][21] DNA intercalating and photocleavage ability, [22] as well as some other ones. [23][24][25][26][27][28][29][30] The oxime fragment is widely used as a linker to obtain conjugates of hydroxylamine and carbonyl compounds.…”

Design, synthesis, and bioactivity evaluation of novel thiochromanone derivatives containing an oxime or oxime ether moiety

“…Thiochromanones, a kind of chromone compound are widely found in numbers of the Umbellifera family [10], is an important scaffold in synthesis of various active molecules extensively used in the intermediate skeleton of drugs and have attracted more and more attention due to their extensive biological activities, including antiviral [11], antibacterial [12,13], antifungal [12,[14][15][16], herbicidal [17,18], and insecticidal [19] activity. Meanwhile, oxime and oxime ester are often used as effective active fragments to design pesticides (such as Trifloxystrobin, Orysastrobin, and Tralkoxydim) due to their extensive bioactivities, including antibacterial [20][21][22], antifungal [23][24][25], antiviral [22,26], herbicidal [27], and insecticidal [28] activity.…”