(RS ) -2 - ( 4,5-dihydro -4-methyl -4-( 1-methylethyl) -5-oxo -1H -imidazol-2 -yl )-3- pyridinecarboxylate

  • 81334-34-1
  • 81510-83-0 ( isopropylamine )

Colorless solid


172-173 ° C

Soluble in water (9.7 g · l-1 at 15 ° C ), dimethyl sulfoxide, methanol and dichloromethane


  • 5000 mg · kg -1 ( LD50, rat, oral)
  • 2000 mg · kg -1 ( LD50, Rabbit, transdermal)

Template: Infobox chemical / molecular formula search available

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

Production and representation

Imazapyr may be obtained by reaction of 2,3- Dicarboxymethylpyridin 2 -aminoamide -3-methyl butane in the presence of tert- butoxide.

Alternatively, it is also the preparation from the reaction of 2- carboxylic acid -3- methylpyridinethylester with chlorine, 2-amino- 2 ,3- dimethylbutyramide in the presence of sodium hydroxide is possible.


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 is more stable to degradation than the ( R)-isomer, which in turn has a higher herbicidal activity.


Imazapyr and its isopropylamine be 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 broadleaf plants. Imazapyr was first registered in 1985 in the U.S. In the GDR, the connection between 1988 and 1994 was approved. The effect is based on inhibition of the synthesis of the amino acid valine, leucine and isoleucine via inhibition of acetohydroxyacid synthase.

The European Commission decided in 2002 not to include imazapyr in the list of permitted pesticide active substances in Annex I to Directive 91/414/EEC.

In Germany, Austria and Switzerland, no plant protection products containing this active ingredient are allowed.