DIHYDROPYRONES, PROCESS FOR THEIR PREPARATION AND HERBICIDAL AGENT CONTAINING THESE DIHYDROPYRONES AS ACTIVE INGREDIENTS

摘要

There are described novel dihydropyrones of the formula I (I) wherein R1 and R2 independently of one another are each a C1-C4-alkyl group, or one of the two substituents is also hydrogen, or R1 and R2 jointly form a C2-C6-alkylene bridge, R3 is C1-C4-alkoxy, C2-C6-alkenyloxy, C2-C4-alkynyloxy, C1-C4-haloalkoxy, C3-C5-alkoxyalkoxy or hydroxyl, and X, Y and Z independently of one another are each hydrogen, halogen, C1-C4-alkyl, C1-C4-alkyl, C1-C4-alkoxy, C1-C4-haloalkyl, C1-C4-haloalkoxy, -S(O)n-C1-C4-alkyl, -S(O)n-C1-C4-haloalkyl, where n is 0, 1 or 2, or they are each C(O)OR4, where R4 is hydrogen or C1-C4-alkyl, or they are each NO2, CN or NR5R6, where R5 and R6 independently of one another are each hydrogen, C1-C4-alkyl, C1-C4-alkylcarbonyl, C 1-C4-haloalkylcarbonyl or C1-C4-haloalkylsulfonyl, processes for producing them, novel starting products used therein, and the use of the novel dihydropyrones. The active substances of the formula I can be used in the form of agriculturally applicable compositions for combating weeds.