Procymidone

Description

Procymidone is a moderately systemic fungicide. It is used in horticulature as a seed-dressing, pre-harvest spray or post-harvest dip for the control of various fungal diseases, such as grey mold, neck rot, brown rot, blossom blight, and twig wilt. It is applied to vegetables including onions, fruits (including peaches, plums, grapes, stone fruit, strawberries, and cherries), and ornamentals.

Uses

Systemic agricultural fungicide.

Uses

Procymidone is a systemic fungcide with both protective and curative activities used to control plant diseases such as fruit rots, grey mould on top fruits, vines and vegetables, and Sclerotinia rot of kidney beans and vegetable crops.

Definition

ChEBI: An azabicycloalkane that is 1,5-dimethyl-3-azabicyclo[3.1.0]hexane-2,4-dione in which the amino hydrogen is replaced by a 3,5-dichlorophenyl group. A fungicide widely used in horticulture as a seed dressing, pre-harvest spray or post-harvest dip for the co trol of various diseases.

Metabolic pathway

The fungicides, chlozolinate, vinclozolin, and procymidone, are added to wine after fermentation and the degradation products are isolated and identified. Chlozolinate undergoes a rapid hydrolytic loss of the ethoxycarbonyl substituent to give an oxazolidine that further undergoes hydrolytic cleavage to give 3' ,5' -dichloro-2-hydroxypropanilide. The oxazolidine ring of vinclozolin undergoes a similar hydrolysis reaction to give the corresponding anilide, 3' ,5'-dichloro-2-hydroxy-2-methylbut-3-eneanilide. Both of these anilides are stable in wine for 150 days. A different degradation behavior is observed with procymidone and leads to the formation of 3,5- dichloroaniline, which, in turn, breaks down in wine.

Degradation

Procymidone (1) was stable in acidic conditions (pH 2) but hydrolysed rapidly in buffer solutions (pH 6 to 10) and in natural river and sea water at 15, 30 and 45 °C with DTm values from 30 min to 8 days. Degradation occurred mainly via cleavage of the cyclic imide linkage in alkaline conditions and via cleavage of the subsequent amide linkage in acidic conditions (Mikami and Miyamoto, 1981) to yield the intermediate acid [2-( 3,5-dichlorophenylcarbamoyl)- 1,2 -dimet hylcyclopropanecarboxylic acid (2) and 1,2-dimethylcyclopropane-1,2-dicarboxylica cid (3) and 3,5- dichloroaniline (4) as terminal products (Villedieu et al., 1994,1995). Pirisi et al. (1986) and Cabras et al. (1984) reported the formation of compound 4 and other polar decomposition products in wine during the fermentation process.
Photodegradation of procymidone was investigated in various solutions after exposure to sunlight. Major degradation pathways were cleavage of the cyclic imide and the subsequent cleavage of the amide linkage to yield compounds 3 and 4 (Mikami and Miyamoto, 1981).