Phenoxycarboxylic acids

Structural formula of 2,4-D

The phenoxycarboxylic acids are a group of chemical compounds whose esters or salts are used as herbicides . They are also known as growth agent herbicides because they cause excessive and undifferentiated growth in plants, which leads to their death. At temperatures below 10 ° C, they usually have little effect.

In the search for synthetic derivatives of the auxin indole-3-acetic acid , 2,4-D and MCPA were found in the early 1940s. It was found that the compounds no longer act as growth regulators in high concentrations , but as selective herbicides against dicots .

Derivatives of 2-phenoxypropionic acid such as dichlorprop, fenoprop and MCPA were later introduced. With them only the d - (+) - form is active. Derivatives of 4-phenoxybutyric acid (e.g. 2,4-DB, MCPB) are converted into corresponding phenoxyacetic acids by β-oxidation in the plant .

Even today, phenoxycarboxylic acids are one of the most important classes of herbicides. They include:

• 2,4-D
• 2,4-DB
• 2,4,5-T
• Dichloroprop
• Fenoprop
• MCPA
• MCPB
• Mecoprop

Individual evidence

1. ↑ Effects of herbicides
2. ↑ ^{a b} Entry on phenoxycarboxylic acids. In: Römpp Online . Georg Thieme Verlag, accessed on November 12, 2014.