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

摘要

A process for prepg. novel dihydropyrone of formula (I) and its acid addn. salt comprises (i) reacting (II) with Mg(OR1)2, (ii) reacting with R2-CH=C(R1)-C(=O)Cl in the inert solvent and (iii) cyclization of produced reactant with alcoholic soln. of strong acid. In the fromula, R1=straight or side chain C1-4-alkyl, R1 and R2 are each C1-4 alkyl, R3=C1-4-(halo) alkoxy, X, Y and Z are each H, C1-4-alkyl or -S(O)n-C1-4-alkyl [n=0, 1 or 2 . The herbicide compsn. contains 0.1-99 wt.% of (I), 1-99.9 wt.% of solid or liq. additive and 0.25 wt.% of surface-active-agent.