Imazapyr

Structural formula
1: 1 mixture of ( R ) -form (left) and ( S ) -form (right)
General
Surname	Imazapyr
other names	( RS ) -2- (4,5-dihydro-4-methyl-4- (1-methylethyl) -5-oxo-1 H -imidazol-2-yl) -3-pyridinecarboxylate
Molecular formula	C 13 H 15 N 3 O 3
Brief description	colorless solid
External identifiers / databases
CAS number 81334-34-1 81510-83-0 (isopropylamine salt) EC number 617-219-8 ECHA InfoCard 100.118.758 PubChem 54738 ChemSpider 49445 Wikidata Q3323027
properties
Molar mass	261.28 g mol −1
Physical state	firmly
Melting point	172-173 ° C
solubility	soluble in water (9.7 g l −1 at 15 ° C), dimethyl sulfoxide, methanol and dichloromethane
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary Caution H and P phrases H: 319-412 P: 273-305 + 351 + 338
Toxicological data	5000 mg kg −1 ( LD 50 ,  rat ,  oral ) 2000 mg kg −1 ( LD 50 ,  rabbit ,  transdermal )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Imazapyr is a chemical compound from the group of the imidazolinones .

Extraction and presentation

Imazapyr can be obtained by reacting 2,3-dicarboxymethylpyridine with 2-amino-2,3-dimethylbutyramide in the presence of tert- butoxide .

Alternatively, it can also be prepared by reacting 3-methylpyridineethyl 2-carboxylate with chlorine and subsequent reaction with 2-amino-2,3-dimethylbutyramide in the presence of sodium hydroxide .

properties

Imazapyr is a colorless solid with a faint odor that is soluble in water. It is stable to hydrolysis at pH values of 5.7 and 9. Imazapyr is chiral , the ( S ) -enantiomer being more stable to degradation than the ( R ) -isomer, which in turn shows a higher herbicidal activity.

use

Imazapyr and its isopropylamine salt are used as a herbicide . It is used for pre- and post-emergence control of a wide range of weeds including annual and perennial grasses and dicotyledonous plants. Imazapyr was first approved in the United States in 1985. In the GDR, the connection was approved between 1988 and 1994. The effect is based on the inhibition of the amino acid synthesis of valine , leucine and isoleucine by inhibiting the acetohydroxy acid synthase .

Admission

In 2002, the EU Commission decided not to include imazapyr in the list of permitted active ingredients in pesticides according to Annex I of Directive 91/414 / EEC.

In Germany, Austria and Switzerland, no pesticides with this active ingredient are permitted.

Individual evidence

1. ↑ ^{a b c d e f} Entry for CAS no. 81334-34-1 in the GESTIS substance database of the IFA , accessed on February 18, 2013(JavaScript required) .
2. ↑ ^{a b c d} Entry on Imazapyr in the Hazardous Substances Data Bank , accessed February 18, 2013.
3. ↑ Entry on 2- [4,5-dihydro-4-methyl-4- (1-methylethyl) -5-oxo-1H-imidazol-2-yl] -3-pyridine carboxylate in the Classification and Labeling Inventory of the European Chemicals Agency ( ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ Imazapyr data sheet , PESTANAL at Sigma-Aldrich , accessed on May 19, 2017 ( PDF ).
5. ↑ Thomas A. Unger: Pesticide synthesis handbook . 1996, ISBN 978-0-8155-1401-5 , pp. 444 ( limited preview in Google Book search).
6. ↑ ^{a b} Terence Robert Roberts, DH Hutson: Metabolic pathways of agrochemicals, Volume 2 . Royal Soc of Chemistry, 1999, ISBN 978-0-85404-499-3 , pp. 364 ( limited preview in Google Book search).
7. ↑ Environmental fate of Imidazolinone Herbicides and their enantiomers in soil and water (PDF; 936 kB), p. 109.
8. ↑ MK Ramezani, DP Oliver, RS Kookana, W. Lao, G. Gill, C. Preston: Faster degradation of herbicidally-active enantiomer of imidazolinones in soils. In: Chemosphere. Volume 79, Number 11, May 2010, pp. 1040-1045. doi : 10.1016 / j.chemosphere.2010.03.046 . PMID 20416927 .
9. ↑ EPA: Reregistration Eligibility Decision for Imazapyr (PDF; 2.3 MB).
10. ↑ Peter Brandt (Ed.): Reports on Plant Protection Products 2009: Active Ingredients in Plant Protection Products ; Approval history and regulations of the Plant Protection Application Ordinance . Springer, 2010, ISBN 978-3-0348-0028-0 , pp. 18 ( limited preview in Google Book search).
11. ↑ Regulation (EC) No. 2076/2002 of the Commission of November 20, 2002 (PDF) extending the deadline according to Article 8 (2) of Council Directive 91/414 / EEC and on the non-inclusion of certain active substances in Annex I of this Directive and the revocation of the approval of plant protection products with these active substances.
12. ↑ General Directorate Health and Food Safety of the European Commission: Entry on Imazapyr in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on February 24, 2016.