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2048767 
Journal Article 
Mechanisms of dicarboximide ring opening in aqueous media: Procymidone, vinclozolin and chlozolinate 
Villedieu, JC; Calmon, M; Calmon, JP 
1994 
1 
Pesticide Science
ISSN: 0031-613X
EISSN: 1096-9063 
BIOSIS/94/25005 
41 
2 
105-115 
eng 
BIOSIS COPYRIGHT: BIOL ABS. The hydrolysis kinetics of the dicarboximide fungicides procymidone, vinclozolin and chlozolinate in neutral and alkaline solutions of pH 6.0 to 13.7 at 25êC have been determined conjointly by ultraviolet spectrophotometry and by high performance liquid chromatography. Under alkaline conditions, the fungicides undergo attack by the hydroxide ion on a specific carbonyl group and the rate of hydrolysis increases proportionally to the hydroxide ion concentration. Procymidone gives quantitatively and irreversibly 2-(3,5-dichlorophenylcarbamoyl)-1,2-dimethylcyclopropanecarboxylate. The reaction is not subject to general base catalysis and experimental data are in agreement with a rate-determining attack by the hydroxide ion. After a rapid hydrolytic loss of the ethoxycarbonyl substituent from chlozolinate, the dicarboximide ring cleavage of the two other fungicides leads, by mechanisms which differ with respect to the type of base catalysis and the rate-determining step, to 
Biochemistry/methods; Biochemistry; Biophysics; Macromolecular systems; Molecular biology; Herbicides; Pest control; Pesticides