| 摘要 |
2,4-Diamino-6-halo-5-trifluoromethylpyrimidines of the formula <IMAGE> (I) wherein X is a halogen atom, especially chlorine or fluorine, and R1 and R2 independently of one another are each hydrogen, C1-C6-alkyl or C3-C6-cycloalkyl, or together form a C3-C7-alkylene bridge, have outstanding selective-herbicidal properties, and are suitable for controlling weeds in crops of cultivated plants, such as maize, cereal or soya-bean. They are produced by aminating 2,4,6-trihalo-5-trifluoromethylpyrimidine, which for its part is obtainable by fluorination of 2,4,6-trihalopyrimidine-5-carboxylic acid. The 2,4,6-trihalo-5-carboxylic acids are novel intermediates, and are obtained by oxidizing 2,4,6-trihalo-2-methyl-, -halomethyl- or -formyl-pyrimidine in sulfuric acid by means of chromium trioxide. |
