MECOPROP-P

Uses

Mecoprop-P has been used as a reference standard for identification of mecoprop enantiomer elution using chiral GC columns. It has also been used as a pesticide in a comparative study to detect the pesticide contamination of indoor air and human hair samples.

Definition

ChEBI: The (R)-enantiomer of 2-(4-chloro-2-methylphenoxy)propanoic acid; the active stereoisomer of the racemic herbicide mecoprop.

General Description

Mecoprop-P, a phenoxyalkanoic acid is widely used as herbicide. It forms colourless and odourless crystals. The (R)-isomer of mecoprop is the active herbicide site. It is generally used for postemergence control of broad-leaved weeds by translocating the herbicide to the roots.

Flammability and Explosibility

Not classified

Synthesis

Starting from racemic α-chloropropionic acid, non-diastereomeric salts are formed with (1-naphthyl)ethylamine, a chiral amine. Stepwise crystallization is applied to resolve the salts to obtain (R)-α-chloropropionate. The salt is hydrolyzed with 3 mol/L aqueous sodium hydroxide solution to yield (R)-α-chloropropionic acid. Subsequently, this product undergoes a condensation reaction with 2-methyl-4-chlorophenol in an aqueous sodium hydroxide system at 90°C and a pressure of 0.25×10⁵ Pa for 25 hours, generating the salt of the target product. Finally, through acidification, extraction and recrystallization purification, Mecoprop-P with an optical purity of 95.9% and a yield of 97% is obtained.