SU1676435A3 - Method for struggle against weeds - Google Patents

Description

This invention relates to chemical methods for controlling weeds and unwanted vegetation.

The aim of the invention is to increase the herbicidal action of the method of controlling weeds, based on the use of a derivative of malonic acid.

Example 1 Preparation of 5- (2-chloro 4-trifluoromethylphenoxy) -2-nitrobenzoylmalonic acid diethyl ester with

This compound is obtained in three ways.

A. To a solution of 38.0 g of 5- (2-chloro-4-trifluoromethylphenoxy) -2-nitrobenzoyl chloride and 50 ml of benzene is added dropwise at room temperature for 30 minutes a solution of ethoxymagneimalonate obtained from 17.6 g of diethyl malonate in 50 ml of benzene. After the addition is complete, the reaction mixture is heated to boiling point for 1 h and then cooled. To the viscous solution 50 ml of 20% sulfuric acid are added with stirring. The phases are separated and the aqueous layer is extracted twice with benzene portion 50 ml each, the extracts are combined, washed with water and with a solution sodium bicarbonate and evaporated. 47.8 g of the expected compound are obtained in the form of a yellow oil, which, after

but

VI

&

coke

CJ

crystallization from a mixture of benzene - hexane has TPL / 2-76 ° C,

B. A mixture of 19, 7 g of 2-chloro-4-trifluoromethylphenol, 32, 7 of 2-nitro-A-fluorobenzoylmalonic acid diethyl ester, 13.8 g of potassium carbonate, and 100 ml of anhydrous dimethyl sulfoxide are stirred at 50 ° C. After 24 hours, the reaction mixture was diluted with 100 ml of water and extracted three times with benzene in 50 ml portions. The benzene phases are dried over anhydrous magnesium sulphate and the solvent is distilled off. The resulting yellow oil is recrystallized from a mixture of benzene and hexane. 40.3 g of the title compound are obtained, mpd 72-V6 ° C o

A mixture of 21.9 g of sodium-2-chloro-4-β-trifluoromethylphenol, 32, / g of 2-nitro-4-fluorobenzoyl-malonic acid diethyl ether and 100 ml of anhydrous dimethylformamide was stirred at 50 ° C. After 24 h, the reaction mixture 25 is diluted with 100 ml of water and extracted three times with benzene in 50 ml portions. The benzene phases are dried over anhydrous magnesium sulfate and evaporated. The resulting yellow oil is recrystallized from a mixture of benzene and hexa20.

thirty

on, receive substance with Tpl 72- / Ь With

Other compounds presented in Table 1C are prepared analogously.

Example 2. Determination of herbicidal action with

Seeds of experimental plants are sown in plastic vessels filled with sand, soil is treated with emulsions of active substances and plants are grown in greenhouse conditions for 4 weeks (pre-emergence treatment)

In post-harvest treatment, the experimental plants are grown under greenhouse conditions until a certain stage of development and then arr. mi active substances.

Evaluation of herbal action was carried out 4 weeks after treatment and expressed in a scale from 0 to 10: O - no damage, 10 - complete death of plants, 1-9 - intermediate values

For comparison, the known herbicidally active compound (A) is used:

С1СООСН (СООС2Н5) 2

The results of the experiments are presented in Table „2 and 3 ,,

Claims (1)

Invention Formula The method of controlling weeds by treating them or the soil on which they grow, is derived from a minor acid, which is different from the fact that where R, is methyl, methylthio, trifluoromethyl, chlorine, cyano, nitro; R is hydrogen, chlorine, fluorine, trifluoromethyl; RJ is hydrogen, chlorine, fluorine; R is hydrogen, chlorine, bromine, cyano, nitro; Ry is methyl, ethyl; Rg is methyl, ethyl, n-propyl at provided that RЈ is n-propyl, st, CF, ST C1 C1 CF, CP, CF, CH. C1 C1 C1 C1 C1 C1 t n n n C1 n C1 n n n F C1 C1 11 | io; i ii. i