Mechanisms of dicarboximide ring opening in aqueous media: Procymidone,vinclozolin and chlozolinate

The hydrolysis kinetics of the dicarboximide fungicides procymidone, vinclozolin and chlozolinate in neutral and alkaline solutions of pH 60 to 13·7 at 25°C 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-dichlorophenylcarba-moyl)-l,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 the corresponding anilides, producing as intermediates the carbamic acids, which undergo loss of carbon dioxide. The hydrolysis of vinclozolin and chlozolinate yields, respectively, N-(3,5-dichloro-phenyt)-2-hydroxy-2-methylbut-3-enanilide and N-(3,5-dichlorophenyl)-2-hydroxy-propanilide.     

Primary feather follicle ablation in common pintails (Anas acuta acuta) and a white-faced whistling duck (Dendrocygna viduata)

Eight 1-yr-old common pintails (Anas acuta acuta) and one 2-yr-old white-faced whistling duck (Dendrocygna viduata) were presented for the persistence of primary flight feathers 1 yr after pinioning. The birds were housed outdoors in an open enclosure necessitating flight prevention. The birds were placed under general anesthesia, and a diode laser was used to ablate the primary feather follicles of the previously pinioned wing. Swelling was the most common side effect seen in seven out of nine treated birds. Other side effects included ulceration, hyperemia, edema, and serosanguinous discharge. All side effects were resolved by 12 wk postprocedure. Laser feather follicle ablation was successful in 28 of 40 (70%) of the treated common pintail feathers, and flight was not observed 7 mo following the procedure in any of these birds. Feather follicle ablation was successful in two of six (33%) of the treated white-faced whistling duck feathers, and the bird in question was observed flying 5 mo after the procedure. Primary feather follicle ablation with a diode laser was a successful method of flight prevention in common pintails but was not effective for a white-faced whistling duck.