SYNTHESIS AND HERBICID ACTIVITY OF ARYLOXYACETIC ACIDS AND AMIDES OF ARYLOXY ACETIC ACIDS CONTAINING CYCLOACETAL FRAGMENT

Abstract

The herbicidal activity of esters and amides based on commercially available phenoxy chlorides and 2,4-dichlorophenoxyacetic acids was studied. Esters of 2,2-methyl-4-hydroxymethyl-1,3-dioxolane, 5-ethyl-5-hydroxymethyl-1,3-dioxane and 1,3-dioxolan-4-ylmethanol and 1,3-dioxane-5 -ol (glycerin formulas), as well as amides containing gem-dichlorocyclopropane and 1,3-dioxolane fragments were obtained. The acid chlorides, 1,3-dioxacycloalkanes and secondary amines were prepared according to standard basic methods. Esters and amides were synthesized from these starting compounds in a short time and with a quantitative yield (more than 90%). As a result of the synthesis of a mixture of 1,3-dioxolan-4-ylmethyl phenylacetate and 1,3-dioxan-5-yl phenylacetate, the content of the 5-ring cyclic derivative over the 6-chain structure was predominant, which is obviously associated with greater activity in the esterification reaction of primary alcohol than secondary. The screening results showed that the activity relative to wheat of the 1,3-dioxalane ester of 2,4-dichlorophenoxyacetic acid is superior to the Octagon-Extra standard. With respect to peas, derivatives of 2,4-dichlorophenoxyacetic acid and 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane are close to the standard for inhibition of shoot mass. The results of N-benzyl-N-[(2,2-dichlorocyclopropyl) methyl] -2-phenoxyacetamide and N-[(2,2-dichlorocyclopropyl) methyl]-N-(1,3-dioxolan-4-ylmethyl)-2-phenoxyacetamide with respect to peas and wheat also showed a marked herbicidal effect, close in value to the reference one. The test results of synthesized benzamides on wheat showed that, at a concentration of 100 mg/l, the compounds act approximately the same as the reference preparation at a dose of 50 mg/l. The obtained results prove the prospects of creating herbicidal preparations based on phenoxy- chlorides and 2,4-dichlorophenoxyacetic acids containing 1,3-dioxacycloalkane fragments. Therefore, these objects are very attractive for further study and synthesis of biologically active compounds containing the above pharmacophore groups.