DIHYDROPYRONES, PROCESSES FOR PRODUCING THEM, NOVEL STARTING PRODUCTS USED THEREIN, COMPOSITIONS CONTAINING THE NOVEL DIHYDROPYRONES AS ACTIVE INGREDIENTS, AND THE USE THEREOF FOR COMBATING WEEDS

摘要

Compounds, and processes to prepare them, of the formula II (II) wherein R3 is C1-C4-alkoxy, C2-C6-alkenyloxy, C2-C4-alkynyloxy, C1-C4-haloalkoxy or C3-C5-alkoxyalkoxy, and X, Y and Z independently of one another are each hydrogen, halogen, 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, C1-C4-haloalkylcarbonyl or C1-C4-haloalkylsulfonyl, with the proviso that, when the phenoxy group is in the p-position, R3 is C1-C4-alkoxy, and two of the substituents X, Y and Z are hydrogen, the third substituent is not hydrogen, fluorine, chlorine, bromine or trifluoromethyl are described. These compounds find use in the preparation of related dihydropyrones of the formula I in which R1 and R2 represent either C1-C4 alkyl groups or one is hydrogen, or together they form a C2-C6 alkylene bridge. These dihydropyrones can be used in combating weeds.