PYRAZOLATE

Uses

Pyrazolynate is a 4-benzoyl pyrazole molecule used for the selective control of annual and some perennial grass and broadleaf weeds in paddy rice in the Far East (as Sanbird) (20).

Definition

ChEBI: Pyrazolynate is a member of the class of pyrazoles that is 1,3-dimethylpyrazole which is substituted at positions 4 and 5 by 2,4-dichlorobenzoyl and p-tosyloxy groups, respectively. It is an obsolete proherbicide (via hydrolysis of the tosylate group to afford the corresponding 5-hydroxypyrazole), that was used to control weeds in rice paddy fields. It has a role as a proherbicide, an EC 1.13.11.27 (4-hydroxyphenylpyruvate dioxygenase) inhibitor, an agrochemical and a carotenoid biosynthesis inhibitor. It is a member of pyrazoles, a tosylate ester, an aromatic ketone and a dichlorobenzene.

Metabolic pathway

Hydrolysis of pyrazolate (DTP) in buffer solutions and in artificial gastric and intestinal fluids proceeds predominantly through base- and acid-catalyzed processes in the regions above pH 7 and below pH 3, respectively, whereas both processes occur between pH 3 and pH 7. The hydrolysis products are p- toluenesulfonic acid and 4-(2,4-dichlorobenzoyl)-1,3- dimethyl-5-hydroxypyrazole. The metabolism study of DTP in fish, rats, plant, soils, and soil microorganisms shows that the metabolites in these systems are mostly derived from the herbicidal entity of pyrazolate resulting from N-demethylation and hydroxylation followed by further oxidation of the methyl group of the pyrazole ring and the cleavage of the carbonyl linkage (see Nakagawa et al.).