Isosteric Substitution in the Design of Safer Pesticides

As for the design of safer drug substances, isosteric substitution has been used for many years for the design of safer pesticide substances, although to a lesser extent. Isosteric replacement of carbon with silicon, for example, has resulted in a number of safe but effective pesticides [76]. An example of the use of isosteric substitution of carbon with silicon in the design of safer a pesticide is in the case of the insecticide MTI-800 (40) and its much less toxic silane isostere, 41. 

MTI-800 is a potent insecticide that is also highly toxicto fish (its LC50 is 3 mg 1 1), which limits its commercial usefulness. Isosteric substitution of the quaternary 

---