TRANSFORMATION RATES OF ORTHO-SUBSTITUTED THIOPHENE AND BENZENE CARBOXYLIC ESTERS - APPLICATION TO THIFENSULFURON-METHYL AND METSULFURON-METHYL HERBICIDES

The rate constants for soil degradation and alkaline hydrolysis of two herbicides, metsulfuron-methyl and thifensulfuron-methyl, have been determined. In order to explain the difference in behaviour of the two compounds, the chemical and enzymatic hydrolysis of some ortho-substituted methyl benzoates and methyl 3-substituted thiophene-2-carboxylates were studied. The data are consistent with a difference in polar and steric effects of the substituents in benzene and thiophene derivatives,