Sulfonylureas degradation products

Bossi, R., Vejrup, K., and Jacobsen, C. S., Determination of sulfonylurea degradation products in soil by liquid chromatography-ultraviolet detection followed by confirmatory liquid chromatography-tandem mass spectrometry, J. Chromatogr. A, 855, 575-582, 1999. 

SPE LC/MS/MS methods have been developed for the determination of polar pesticides (as propanyl, thiobencarb, diuron, simazine, bentazone etc.) and of their degradation products in waters with LOQ aronnd 25 ng L (Figure 18.1) [73], for the determination of chloroacetamide herbicides (LOD=25ng L ) [74], of sulfonylureas, bentazone, and phenoxyacids in river and drainage waters (LOD of the order of few ng L" ) [9]. 

Agrochemical Products. The principal thiophene derivative in herbicidal protection, one of a range of sulfonylurea herbicides, is Harmony [79277-27-3] (Du Pont) (60), based on the intermediate methyl 3-aminothiophene-2-carboxylate (9). The product is characterized by a rapid bio degradability in the soil. Many other thiophene derivatives have been shown to have agrochemical activity, but few of these have been developed to the commercial level. 

Microsomes isolated from shoot tissues of etiolated wheat seedlings (Tritkum aestivum L. var. Olaf) oxidized the sulfonylurea herbicide prosulfuron (CGA 152005). Identification of the major oxidation product as l-(4-methoxy-6-methyl-l,3,5-triazin-2-yl)-3-[2-(3,3,3-trifluoropropyl)-5-hydroxyphenylsulfonyl]-urea 28 was confirmed by proton NMR spectroscopy (Figure 15). Proton NMR spectra of isolated minor oxidation products were not obtained because of insufficient sample size for analysis. However, these products were identified tentatively as l-[4-(hydroxymethyl)-6-methoxy-l,3,5-triazin-2-yl]-3-[2-(3,3,3-trifluoropropyl)phenylsulfonyl] urea 29 and an intermediate oxidation product l-[4-[(hydroxymethyl)oxy]-6-methyl]-l,3,5-triazin-2-yl]-3-[2-(3,3,3-trifluoropropyl)phenylsulfonyl]urea 30, that degraded to l-(4-hydroxy-6-methyl-l,3,5-triazin-2-yl)-3-[2-(3,3,3-trifluoropropyl)phenylsulfonyl]urea 31 <19%JFA3658>. 

---