1,3-Dimethyl-4-acyl-5-hydroxypyrazoles were treated with methyl isocyanate to give corresponding carbamates. They were 1,3-dimethyl-4-benzoyl-pyrazol-5-yl N-methylcarbamate(V), 1, 3-dimethyl-4-(2-chlorobenzoyl)-pyrazol-5-y1 N-methyl-carbamate(VI), and 1, 3dimethyl-4-(2,4-dichlorobenzoy1)-pyrazol-5-yl N-methyl-carbamate(VII). The structures of the compounds were fully identified by UV, IR, ¹H-NMR and ^(13)C-NMR.
The synthesized carbamate compounds were tested for the phytotoxicity on the seed germination and the seedling growth of rice, radish, green-pea and turf grass. At 50ppm concentraction, the germination of seeds was not significantly affected. At higher concentraction, however, phytotoxic tendency on the seed germination and seedling growth was observed. In addition, these compounds were less phytotoxic to rice and turf seedlings as compared with radish and green pea seedlings.
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