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The soil degradation of the herbicide florasulam
Author(s) -
Jackson Roy,
Ghosh Dipankar,
Paterson Glen
Publication year - 2000
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/1526-4998(200012)56:12<1065::aid-ps252>3.0.co;2-y
Subject(s) - chemistry , decarboxylation , sulfonamide , metabolite , degradation (telecommunications) , carboxylic acid , organic chemistry , stereochemistry , biochemistry , telecommunications , computer science , catalysis
The route and rate of degradation of florasulam, a low‐rate triazolopyrimidine sulfonanilide herbicide, was investigated in six soil types under aerobic conditions at 20 or 25 °C. Degradation products were isolated and identified by mass spectroscopy. Florasulam was rapidly degraded by microbial action with an average half‐life of 2.4 days (range 0.7 to 4.5 days). The first step in the degradation pathway involved conversion of the methoxy group on the triazolopyrimidine ring to a hydroxy group to form N ‐(2,6‐difluorophenyl)‐8‐fluoro‐5‐hydroxy[1,2,4]triazolo[1,5‐ c ]pyrimidine‐2‐sulfonamide. This metabolite degraded, with a half‐life of 10 to 61 days, via partial breakdown of the triazolopyrimidine ring to form N ‐(2,6‐difluorophenyl)‐5‐aminosulfonyl‐1 H ‐1,2,4‐triazole‐3‐carboxylic acid. This was followed by cleavage of the sulfonamide bridge to form 5‐(aminosulfonyl)‐1 H ‐1,2,4‐triazole‐3‐carboxylic acid. Other degradation processes involved decarboxylation of the carboxylic acid metabolites and mineralisation to form carbon dioxide and non‐extractable residues. © 2000 Society of Chemical Industry