Dimethoxypyrimidines as Novel Herbicides. Part 2. Synthesis and Herbicidal Activity ofO-Pyrimidinylsalicylates and Analogues

Abstract

Abstract:A new series of the 0-pyrimidinylsalicylates was synthesized and their herbicidal activity was examined. Some of these compounds showed very strong herbicidal activity under pre-and post-emergent treatment conditions against various kinds of grass and broadleaf weeds. Among these compounds, 0-(4, 6-dimethoxypyrimidin-2-yl) salicylic acid and its methyl ester were found to exhibit the highest activity. The herbicidal symptoms observed after the treatments included early cessation of plant growth followed by chlorosis, necrosis and plant death. The symptoms were similar to those caused by sulfonylureas and imidazolinones, which inhibit branched-chain amino acid biosynthesis.Key words: pyrimidinyl salicylates, methyl 0-(4-chloro-6-methoxypyrimidin-2-yl) salicylate, 2-alkanesulfonylpyrimidines, methyl 0-(4, 6-dimethoxypyrimidin-2-yl) salicylate, methyl 0-(4, 6-dimethoxy-s-triazin-2-yl) salicylate, acetolactate synthase, sulfonylureas.

Gas Phase Chemistry of Li+with Amides: the Observation of LiOH Loss in Mass Spectrometry

“…One class of amides that are of interest are pesticide precursors, such as 2-(4, 6-dimethoxypyrimidin-2-ylsulfanyl)-N-phenylbenzamide and its derivatives [44,45]. Here we report our studies of the gas phase chemistry of Li + adducts of these compounds upon ESI-MS/MS, and among the fragment ions we observe are those reflecting loss of LiOH.…”

Pyrimidinylsalicylic Based Herbicides: Modeling and Prediction

“…The synthesis and herbicidal activity of pyrimidinylsalicylic acid (PSA) based compounds, Figure 2, was reported for first time by Nezu et al (Nezu et al, 1996;Nezu et al, 1998). These compounds show highly potent herbicidal activity characteristic of AHAS inhibition.…”

Gas-phase smiles rearrangement reactions of deprotonated 2-(4, 6-dimethoxypyrimidin-2-ylsulfanyl)-N-phenylbenzamide and its derivatives in electrospray ionization mass spectrometry

“…O-pyrimidinylsalicylates show very strong herbicidal activity under pre-and postemergent treatment conditions against various grasses and broadleaf weeds [1,2]. Also, the 2-(4,6-dimethoxypyrimidin-2-ylthio)benzoic acid derivatives are found to exhibit herbicidal activities against grasses and broadleaf weeds over a wide range of growth stages [3,4].…”