| 摘要 |
<p>The herbicide contains at least one 1,3-dioxane of the formula: <IMAGE> and an extender. To prevent and destroy undesired vegetation, a herbicidally effective amount of a 1,3-dioxane of the formula I is applied to the site to be protected. To prepare 1,3-dioxanes of the formula I, a substituted 5-hydroxy-1,3-dioxane of the formula <IMAGE> is treated with an alkali metal base in a solvent. The resulting alkali metal alocoholate is then reacted with a compound of the formula R<r>-CH2-Cl or R<r>-CH2-Br. Finally, the product of the formula I is separated from the reaction mixture. In the formulae, R<2>, R<2a>, R<4>, R<5>, R<6> and R<r> have the meanings given in Patent Claim 1. The group -OCH2-R<r> or the hydroxyl group is in the cis-position relative to R<2> if R<2> is not hydrogen.</p> |
