Synthesis and Biological Activity of Photopolymerizable Derivatives of Glyphosate^†

The synthesis of new acrylate and methacrylate derivatives of a glyphosate is reported. Two isomers resulting from a hindered rotation around the amide C−N bond are observed for both acrylic and methacrylic analogs, and barriers for internal rotation are obtained. Biological activity tests indicate that functionalized glyphosates possess herbicidal activity similar to that of the parent compound. Only the acrylated glyphosate derivatives undergo photopolymerization. The resulting photopolymer of acrylated glyphosate retains the biological activity. The methacrylated glyphosates are unreactive. Differential reactivity is explained by the different conformational preferences of the functionalized glyphosates. The experimental findings are supported by the results of density functional theory geometry optimizations.