Quizalofop-ethyl

Structural formula
Stereoisomers of quizalofop-ethyl: ( R ) -form (left) and ( S ) -form (right)
General
Surname	Quizalofop-ethyl
other names	( RS ) -2- [4- (6-chloroquinoxalin-2-yloxy) phenoxy] propionic acid ethyl ester ( IUPAC )
Molecular formula	C 19 H 17 ClN 2 O 4
Brief description	white solid
External identifiers / databases
CAS number 76578-14-8 (quizalofop-ethyl) 100646-51-3 (Quizalofop-P-ethyl) EC number 616-351-3 ECHA InfoCard 100.114.176 PubChem 53518 ChemSpider 48336 Wikidata Q27155607
properties
Molar mass	372.08 g mol −1
Physical state	firmly
density	1.35 g cm −3
Melting point	76-78 ° C
solubility	practically insoluble in water (0.3 mg l −1 at 20 ° C) soluble in benzene, xylene and acetone
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 302-312-413 P: 280
Toxicological data	1182 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Quizalofop-ethyl is a chemical compound from the group of aryloxyphenoxypropionic acid - herbicides (a subgroup of the derivatives of phenoxyacetic acid and quinoxaline ).

Quizalofop-ethyl is a representative of the quizalofop herbicides , structurally it is the ethyl ester of quizalofop, the free acid.

Extraction and presentation

Quizalofop-ethyl can be obtained from propionic acid. This is chlorinated to 2-chloropropionic acid and then esterified with ethanol . The intermediate product then reacts with hydroquinone and 2,6-dichloroquinoxaline to form the end product.

properties

Quizalofop-ethyl is a colorless solid that is insoluble in water. It is unstable when exposed to light.

Stereoisomerism

Quizalofop-ethyl has one center of chirality and can therefore exist in two mirror-image forms, the ( R ) and the ( S ) isomer. The technical synthesis product is a racemic mixture of both isomers. The more effective ( R ) -isomer is called quizalofop-P-ethyl.

effect

The effect of quizalofop-ethyl is based on the inhibition of fatty acid - biosynthesis by engagement in the mode of action of the enzyme acetyl coenzyme A carboxylase .

Use and approval status

Quizalofop-ethyl is next quizalofop as a selective post-emergence - herbicide used that, but not against annual and perennial grasses against sedges used and broadleaf weeds. It was approved in the USA in the late 1980s.

Quizalofop-P-ethyl was approved for use as a herbicide in the EU with effect from December 1, 2009. Plant protection products with Quizalofop-P are only available in Switzerland, but not in Germany or Austria.

Individual evidence

1. ↑ ^{a b c d e f} data sheet Quizalofop-p-ethyl, PESTANAL at Sigma-Aldrich , accessed on May 19, 2017 ( PDF ).
2. ↑ ^{a b c} Entry on QUIZALOFOP-ETHYL in the Hazardous Substances Data Bank , accessed on July 29, 2012.
3. ^ ^{A b c} Terence Robert Roberts, David Herd Hutson: Metabolic Pathways of Agrochemicals: Herbicides and plant growth regulators . Royal Society of Chemistry, 1998, ISBN 0-85404-494-9 , pp. 124 ( limited preview in Google Book search).
4. ↑ Rudolf Heitefuss: Plant protection: Basics of the practical Phytomedicin . Georg Thieme Verlag, 2000, ISBN 3-13-513303-6 , p. 211 ( limited preview in Google Book search).
5. ↑ Thomas A. Unger: Pesticide Synthesis Handbook . William Andrew, 1996, ISBN 0-8155-1853-6 , pp. 776 ( limited preview in Google Book search).
6. ↑ ^{a b} EPA: Quizalofop Summary Document ( Memento of April 12, 2013 in the Internet Archive ). December 2007.
7. ↑ General Directorate Health and Food Safety of the European Commission: Entry on Quizalofop-P-ethyl in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on February 23, 2018.