RU2776586C1 - N-aryl-3[(cyanomethyl)amino]-4,6-dimethylthieno[2,3-b]-pyridine-2-carboxamides as 2,4-d antidotes on sunflower - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to N-aryl-3-[(cyanomethyl)amino]-4,6-dimethylthieno[2,3-b]-pyridine-2-carboxamide formulas 1-2, where 1) X = 2-methylphenyl; 2) X = 4-bromophenyl.

EFFECT: new compounds have been obtained that can be used in the agriculture to protect sunflower plants from the phytotoxic effect of the herbicide of 2,4-dichlorophenoxyacetic acid (antidotes).

1 cl, 2 tbl, 2 ex

Description

The invention relates to new synthetic, chemical biologically active substances from a number of heterocyclic compounds used to protect sunflower plants from the phytotoxic effect of the herbicide 2,4-dichlorophenoxyacetic acid (antidote).

As you know, sunflower is an extremely sensitive crop to herbicides of the 2,4-D group, and, in cases of unintentional contact of the herbicide on its crops, losses can be, depending on the dose, up to 100% [Chkanikov D.I., Sokolov M.S. Herbicidal action of 2,4-D and other halophenoxy acids, M.: Nauka, 1973, - 95 s].

Despite intensive research to find new antidotes for the protection of vegetative sunflower plants from the damaging effects of 2,4-D, it remains relevant and unresolved [Strelkov V.D., Dyadyuchenko L.V., Dmitriev I.G. Synthesis of new herbicidal antidotes for sunflower. Krasnodar: Enlightenment-South, 2014. S. 79]. Until now, the protection of vegetative sunflower plants from the damaging effects of 2,4-D remains relevant and unresolved.

The closest analogue in structure and properties of the claimed compounds is N-(4-fluorophenyl)-3-amino-4,6-dimethylthieno[2,3-b]pyridyl-2-carboxamide formula 3 [US Pat. No. 2277333 RF, IPC Α01Ν 25/32 (2006.01) А01Р 15/00 (2006.01)]

Compound 3 (prototype) in the field at a dose of 200 g/ha on vegetative sunflower plants exhibits an antidote effect against 2,4-D of about 23% and can be used as a means of sunflower protection. However, its antidote activity is not high enough, while the dose of 200 g/ha is high enough to cause negative environmental problems.

The technical result of the claimed invention is the expansion of the arsenal of biologically active substances obtained synthetically for their use in agriculture as antidotes.

This is achieved by using N-aryl-3-amino-4,6-dimethylthieno[2,3-b]-pyridyl-2-carboxamides of formula 1-2:

where 1 X=2-methylphenyl;

2 X=4-bromophenyl;

exhibiting antidote activity against 2,4-dichloro-phenoxyacetic acid on sunflower.

The claimed compounds are obtained by the interaction of 4,6-dimethyl-5-Px.-3-cyano-2(1H)-pyridinethione with N-aryl-2-chloroacetamide in the presence of an equivalent of KOH in a DMF solution, an intermediate product is synthesized, which, without isolation from the reaction mass, with the addition of an equimolar amount of alkali, it cyclizes into target compounds 1-2 in accordance with the following scheme:

[A.V. Kadushkin, I.F. Faermark, G.Ya. Mark, V.G. Granik. Synthesis and biological properties of 4-phenylamino-, 4-dimethylamino-3-cyano-pyridinethiones-2 and the preparation of thieno[2,3-b]pyridines on their basis - Chem. farm. and. - 1992. - T. 26. - No. 11-12. - S. 62-66].

Example 1 Evaluation of compounds 1-2 for antidote activity on sunflower seedlings.

Germinated sunflower seeds with a germinal root length of 2–4 mm were placed for 1 hour in a solution of 2,4-dichlorophenoxyacetic acid (2,4-D) at a concentration of ^10–3 % in order to obtain 40–60% inhibition of hypocotyl growth. After the herbicidal action, the seedlings were washed with water and placed in solutions tested for antidote activity of substances at concentrations of 10 ^-2 , 10 ^-3 , 10 ^-4 , 10 ^-5 % (herbicide + antidote option). After 1 hour, the seeds were washed with water and laid out on filter paper strips (size 10×75 cm), 20 pieces each, which were rolled up and placed in glasses with 50 ml of water. Further germination of seeds was carried out in a thermostat for 3 days at a temperature of 28°C. The temperature of the solutions and wash water is 28°C.

Seeds of the "herbicide" variant (reference standard) were kept for 1 hour in a solution of 2,4-D at a concentration of 10 ^-3 % and for 1 hour in water.

The seeds of the control variant were kept in water for 2 hours.

The experiment was repeated three times. In each repetition, 20 seeds were used.

The protective (antidote) effect was determined by the increase in the length of the hypocotyl and root in the herbicide + antidote variant relative to the named values in the “herbicide” variant (standard) in percent.

Statistical processing of experimental data was carried out using Student's t-test at P=0.95.

The research results are shown in the table. As can be seen from the data in the table, the use of N-aryl-3-[(cyanoacetyl)amino]-4,6-dimethylthieno[2,3-b]-pyridyl-2-carboxamides 1-2, proposed as antidotes, against the background of herbicide exposure, sharply weakens toxic effect of the herbicide.

Compounds 1-2 reduced the negative effect of 2,4-D on the hypocotyls of sunflower seedlings by 29-42% when used mainly in three or more concentrations, while compound 3 (analogue in structure) showed an antidote effect of 5-29%.

Compounds 1-2 reduced the inhibitory effect of 2,4-D on the roots of seedlings by 30-53% also when used in three or more concentrations, compound 3 did not increase the length of the seedling root, and the prototype showed an antidote effect at the level of 20-21%.

Example 2 Evaluation of compounds 1-2 and 3 for antidote activity on sunflower plants under field experimental conditions.

Evaluation of the antidote activity of the claimed compounds 1-2 and the prototype (compound 3) was carried out on the experimental field VNIIBZR. The tests were carried out according to the following procedure.

Under field conditions, sunflower plants of the Master variety in the phase of 10-16 leaves were treated with an aqueous solution of 2,4-dichlorophenoxyacetic acid at a dose of 18 g/ha and after 3 days an antidote solution was applied at a dose of 100 g/ha with a working fluid consumption rate of 300 l/ha .

Experience has the following options:

- control - untreated plants;

- "herbicide" (standard) - plants treated with herbicide;

- "herbicide + antidote" - plants treated with herbicide and antidote.

The experiments were carried out on plots with an area of 2.8 m ² , repeated five times. Sunflower harvesting was carried out at the time of full ripening of seeds.

The antidote effect was determined by the absolute value of the yield increase to the herbicidal standard and as a percentage by the formula:

And _x - antidote effect,%;

A - crop in the antidote + herbicide variant;

E - crop in the version of the standard (herbicide).

The obtained data were statistically processed using Student's t-test.

The test results are presented in the table.

Differences between the variants are significant at Ρ=0.90

Thus, the use of the claimed N-aryl-3-[(cyanoacetyl)amino]-4,6-dimethylthieno[2,3-b]-pyridyl-2-carboxamides as 2,4-D antidotes on sunflower makes it possible to provide an effect on level of 55-64% versus 23% for the prototype, as well as to expand the range of known antidotes.

Claims (4)

N-aryl-3-[(cyanoacetyl)amino]-4,6-dimethylthieno[2,3-b]-pyridyl-2-carboxamides

, where 1) X = 2-methylphenyl; 2) X = 4-bromophenyl, exhibiting antidote activity against 2,4-dichlorophenoxyacetic acid on sunflower.