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.