SYNTHESIS AND HERBICIDAL ACTIVITY OF PYRIMIDINYL SALICYLIC AND THIOSALICYLIC ACIDS

A series of the O-pyrimidinylsalicylic acids were synthesized and thei r herbicidal activity was evaluated. Investigation of substituents on the benzene ring revealed that the 6-halogeno derivatives exhibited hi gh herbicidal activity, but with severe phytotoxicity to some crops, T he replacement of a bridge atom between two rings with other atoms or groups was performed. The S-pyrimidinylthiosalicylic acids replaced by sulfur improved the safety to cotton plants dramatically reducing her bicidal activity against broadleaf weeds to some extent. Out of the S- pyrimidinylthiosalicylic acids, hloro-2-(4,6-dimethoxypyrimidin-2-yl)t hiosalicylic acid was selected as a quite promising compound for the d evelopment of a possible cotton field herbicide.