Herbicide selectivity oxidative reactions

The multiple bond is expected to be very strong, in addition to being favored by the positive entropy change associated with chelation reactions (see discussion on chelation in Chapter 1). Glyphosate is readily and selectively adsorbed by Fe oxides, and its herbicidal function is rapidly inactivated on contact with soils, evidence of a strong surface interaction. 

This homogeneous catalytic conversion is novel and represents, in effect, an oxidative dealkylation of one carboxymethyl moiety, yielding the N-substituted glycine. The reaction is selective to the desired product PMG when carried out at the natural pH of the free acid substrate (approximately 1-2) and when carried out at substrate loadings less than 5% by weight. PMG is the active agent in the herbicide Roundup... 

Studies reported in this section would appear to confirm that a real potential exists for modifying the ability of plants to detoxify herbicides, and thus change their selectivity profiles, by limiting the activities of their oxidative enzyme machinery. Further developments along these lines, however, will need to be underpinned by a greater fundamental knowledge of the biochemistry of microsomal hydroxylation reactions, in both crop and weed species. 

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