NMR and Molecular Mechanics of Alachlor Conformation and Conformers: Implications to the Mechanism of Environmental Photodegradation

Hindered intramolecular free rotation around specific single bonds within alachlor accounts for the existence of the stable conformers observed in solution by NMR spectroscopy. NMR and molecular mechanics techniques enable identification of the molecular chemical environment under which specific conformations of alachlor are changed. Results suggest the photodegradation products previously reported have one of these conformers as a common intermediate. Chemical environments that increase the amount of this conformer could therefore enhance its rate of photodegradation. Chemical environments that stabilize a different conformation may have significantly longer half-lives or different photodegradation products.