Introduction

Many commercial agrochemicals in current use contain chiral structures and thus consist of enantiomers. Here chiral herbicide is one of the most important agrochemicals which are widely used. Enantiomers of a chiral compound have identical physical-chemical properties and appear as a single compound in standard analysis. However, the biological effects of enantiomers such as toxicity, mutagenicity, carcinogencity, and endocrine disruption activity, are generally different, due to the inherent enantioselectivity of biological interactions.

According to the chemical structure, the familiar chiral herbicides have been classified with amide herbicides, phenoxy herbicides, imidazolinone herbicides, organophosphorus herbicides and so on. The analysis and preparation of pure enantiomer herbicides have been summarized with HPLC, GC, CE and SFC methods. Finally, information concerning the stereoselective toxicity and degradation of chiral herbicides in environmental behavior has been offered.

2. Classification of chiral herbicides 2.1 Amide herbicides

tf^ 'iXrVO

benzoylprop flamprop arylalanine herbicides

ii s

pyrimisulfan pyrimisulfan y—1

Or metolachlor acetochlor prynachlor chloroacetanilide herbicides O

HN'S-Cl O lOCl

HN'S-Cl O lOCl

OF profluazol sulfonanilide herbicides

napropamide

beflubutamid dimethenamid

2.2 Phenoxy herbicides

Cl O

clomeprop

fluroxypyr-meptyl

fluroxypyr-meptyl

difenopenten

F3C ^ v difenopenten

ClO 2,4-D-ethylhexyl

MO2 etnipromid Ov

trifopsime

cloprop

cloprop

4-CPP

4-CPP

Cl O

dichlorprop

Cl O

fenoprop phenoxypropionic herbicides

CH3 O mecoprop

chlorazifop

clodinafop

cyhalofop

ClA r0

clofop diclofop

F3C\

fluazifop trifop

fenoxaprop

fenthiaprop

haloxyfop

isoxapyrifop

quizalofop 0

quizalofop 0

metamifop propaquizafop aryloxyphenoxypropionic herbicides n—^ y

2.4 Organophosphorus herbicides

amiprofos-methyl

fosamine

0 0

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