Fungicidal activity of N-(2-cyano-2-methoximinoacetyl)amino acids and their derivatives

More than 20 N‐(2‐cyano‐2‐methoximinoacetyl)amino acids and derivatives were synthesised and tested for antifungal activity against grape downy mildew, caused by Plasmopara viticola (de Bary) Berl. & de Toni, and rape downy mildew, Peronospora parasitica Fr. Two of the compounds containing a free carboxylic acid group, a moiety which has been shown to confer phloem mobility on compounds, showed high activity, especially against P. parasitica, in protectant tests. These results indicate that there is no incompatibility between the acid function and fungicidal activity. A number of the esters showed activity comparable with that of cymoxanil in the protectant tests, and the tert‐butyl esters of the methionine derivative and its sulfone were more than ten times as active as the commercial compound.