Comparison of Phytotoxicities between 4-Fluorinated and Non-fluorinated 2-Chloro-5-(3, 4, 5, 6-tetrahydrophthalimido)benzoates

Abstract

Protoporphyrinogen-IXoxidase inhibition and peroxidizing phytotoxicity were determined using a series of fluorinated and non-fluorinated alkyl 2-chloro-5-(3, 4, 5, 6-tetrahydrophthalimido)benzoates and their parent benzoic acid derivatives. Protoporphyrinogen-IX oxidase from corn etioplasts was extracted, and ethane formation by intact cells of the green algae Scenedesmus acutus was measured. The benzoates with a fluorine atom exhibited stronger peroxidizing phytotoxicity (higher ethane formation) than the benzoates having no fluorine atom although protoporphyrinogen-IX oxidase inhibition by the fluorinated analogues was found to be weaker or almost equal to the non-fluorinated analogues. These data strengthen and generalize our previous findings with cyclic imides having an N-(4-chloro-2-fluoro-5-carboxyphenyl) group. The fluorinated analogues, which are not necessarily stronger protoporphyrinogen-IX oxidase inhibitors, exhibit stronger peroxidizing phytotoxicity with intact plant cells than those without a fluorine atom.

Enzymatic Activity of Protoporphyrinogen-IX Oxidase from Various Plant Species

“…Anjou (ZmA), DK212, DK652 and LG2205) was determined according to our methods. [8][9][10][11] Enzyme activity of other 30 plants, 14 monocotyledons and 16 dicotyledons (see Tables 1 and 2), was assayed by the following procedure; (1) the seeds were germinated on filter paper in the dark at 30°C for 5-21 days indicated in Tables 1 and 2, e.g. for 7 days for Lolium perenne (Lop) and Echinochloa utilis (Ecu), for 6 days for Agrostemma githago (Agg), for 10 days for Arabidopsis thaliana (Art).…”

Synthesis and Herbicidal Activity of 2-(7-Fluoro-3-oxo- 3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)isoindoline-1,3-diones

“…Thousands of active compounds exhibiting this mode of action have been synthesized (1)(2)(3)(4)(5). On the basis of their chemical structures, these compounds can be classified as diphenyl ethers (6,7), benzoxazinones (8), phenyl imides (9)(10)(11)(12), triazolinones (13), tetrazolinones (14), oxadiazolones (15), thiadiazolidines (16), isothiazolones (17), and arylpyrroles (18). 2-(7-Fluoro-3-oxo-3,4-dihydro-2H-benzo-[b] [1,4]oxazin-6-yl)-4,5,6,7-tetrahydro-2H-isoindoline-1,3-diones are a class of phenylimide protoxinhibiting herbicides (19,20).…”