JPH06754B2 - Substituted pyridyl urea derivative and herbicide containing the compound as an active ingredient - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel substituted pyridylurea derivative and a herbicide containing the derivative as an active ingredient. More specifically, the present invention comprises N '-[2- (4-isopropylphenoxy) pyridyl-5] -N-methoxy-N-methylurea represented by the following formula (I) and the compound as an active ingredient. It relates to a characteristic herbicide.

[Problems to be Solved by Conventional Techniques and Inventions] Conventionally, many herbicides have been developed and put into practical use,
It is hard to say that all of these herbicides are sufficient in terms of herbicidal activity, selectivity, safety, etc., there is no phytotoxicity to target crops, they kill harmful weeds in small amounts, and they have no adverse effect on the environment. There is a need for no herbicides. In particular, regarding herbicides acting on fields, there is a demand for a herbicide that is safe for the crop even when the foliage of the crop and the weeds are simultaneously treated and that can selectively kill only the weed. The inventors of the present invention, in order to meet these demands, as a result of diligent research, a urea derivative represented by the formula (I) shows a killing effect on weeds by foliar treatment with an extremely low dose, and in crops. On the other hand, they have found that they are extremely safe and have reached the present invention.

〔The invention's effect〕

That is, the compound of the present invention shows no phytotoxicity against important crops such as soybean, corn, wheat, rice, peanut, etc., and exhibits an excellent selective selective control effect against weeds at a low dose. The herbicide of the present invention exerts a remarkable selective control effect particularly when used as a post-emergence foliar treatment agent for upland weeds. For example, when the herbicide of the present invention is applied to a soybean field as a foliar treatment agent, many field-important weeds such as velvetleaf, gall fir, white mosquito, Kosendangsa, and Amaranthus can be killed at a low drug concentration, but soybean has no phytotoxicity. Don't give.

The compound of the present invention is disclosed in JP-A-56-36456 and US Pat. No. 4,334.
No. 912 is included in the general formula showing the active ingredient described in No. 912, but no specific description or suggestion is given about the compound of the present invention. Moreover, as shown in the Examples below, the compounds of the present invention have far higher herbicidal activity and far higher safety against crops than the compounds described in the above publications. The strength of herbicidal activity and the safety against crops, as seen in the compounds of the present invention, are significantly changed by a slight structural difference, and cannot be predicted by simple structural analogy. The excellent action of the compound of the present invention can be considered to be extremely specific.

[Synthesis method]

The compound of the present invention, that is, N '-[2- of the above formula (I)
(4-Isopropylphenoxy) pyridyl-5] -N-
Methoxy-N-methylurea is synthesized by the following three general methods (AC).

Both reactions are carried out at 0 ° C. to 150 ° C. in an inert solvent such as benzene, toluene, xylene, methylene chloride, chloroform, tetrahydrofuran, ethyl acetate and dimethyl sulfamide, and the reaction time is 30 minutes to 12 hours. In Methods A and C, the target compound of the present invention can be obtained in good yield by using a base such as pyridine, triethylamine, sodium hydroxide, potassium hydroxide or potassium carbonate as a dehydrochlorinating agent. Further, in Method C, better results are obtained by adding a catalyst such as copper powder or copper iodide. After completion of the reaction, the target compound is obtained from the reaction mixture according to a conventional method.

[Synthesis example]

 Next, a synthetic example of the present compound will be given as a reference example.

Reference Example 1 2- (4-isopropylphenoxy) -5-
Synthesis of aminopyridine 2- (4-isopropylphenoxy) -5-nitropyridine 7.0 g was dissolved in ethanol 35 ml, and catalytic reduction was performed using 5% palladium carbon 0.35 g as a catalyst. When the absorption of hydrogen is over, the catalyst is separated, the liquid is distilled off under reduced pressure,
5.87 g of pale yellow crystals of 2- (4-isopropylphenoxy) -5-aminopyridine were obtained (yield 95%).

Melting point: 75.0 to 75.6 ° C C (%) H (%) N (%) Elemental analysis value: 73.66 7.06 12.27 Calculated value (as C ₁₄ H ₁₆ N ₂ C) Measured value 73.84 7.23 12.40 Reference example 2 N ′-[2 Synthesis of-(4-isopropylphenoxy) pyridyl-5] -N-methoxy-N-methylurea Dissolve 5.5 g of 2- (4-isopropylphenoxy) -5-aminopyridine in pyridine 27.5, and under ice cooling, N-methoxy- 3.55 g of N-methylcarbamoyl chloride was added to toluene 1
A solution dissolved in 1 m was dropped. After reacting for 4 hours at room temperature, the reaction mixture was poured into saturated saline and extracted with ethyl acetate. The extract was washed with saturated saline and dried over magnesium sulfate. The solvent was distilled off under reduced pressure, and the obtained oily substance was recrystallized from a mixed solvent of hexane-ethyl acetate to obtain 6.71 g of white crystals (yield 88.6%).

Melting point: 93.7-94.5 ° C IR (KBr): 3295,2940,1650,1524,1502,1474,1322,1270,1
258,1228,1200,1183,1123,1112,1030,1012,887,842,74
0,666cm ^-1 NMR δCDCl ₃ : 1.24 (d, 6H), 2.90 (m, 1H), 3.20 (s, 3H), 3.70
(s, 3H), 6.90 (d, 2H), 6.95 (d, 1H), 7.20 (d, 2H), 7.98 (d, 1
H), 8.10 (dd, 1H), 8.36 (bs, 1H). Elemental analysis C (%) H (%) N (%) Calculated value: 64.74 6.71 13.32 (as C ₁₇ H ₂₁ N ₃ O ₃ ) Measured Value 64.91 6.65 13.51 [Herbicide] When the compound of the present invention is actually used as a herbicide, the active ingredient may be used alone, or the active ingredient may be used in various auxiliary agents such as It can be used in the form of emulsion, wettable powder, powder, granule or the like by adding a diluent, a solvent, a surfactant and the like.

Examples of the diluent include clay, talc, bentonite, kaolin, diatomaceous earth, white carbon, vermiculite, slaked lime and silica sand, and examples of the solvent include alcohol, dioxane, acetone, cyclohexane, dimethylformamide and the like. Can
Surfactants include alkylbenzene sulfate, alkylbenzene sulfonate, polyoxyethylene glycol ether, polyoxyethylene alkylaryl ether, polyoxyethylene sorbitan monoalkylate, sodium alkyl sulfate, sodium alkylnaphthalenesulfonate, sodium ligninsulfonate, etc. Can be illustrated, and these additives can be blended in an appropriate ratio.

Next, formulation examples will be described. The numbers indicate weight percentages.

Formulation Example 1 (Wettable powder) Compound of the present invention 10% Higher alcohol sulfate sodium salt 3% Kaolin 87% The above are uniformly mixed and pulverized to obtain a wettable powder.

Formulation Example 2 (Emulsion) The compound of the present invention 20% polyoxyethylene alkylaryl ether 10% cyclohexanone 10% xylene 60% The above ingredients are uniformly dissolved to obtain an emulsion.

Formulation Example 3 (Granule) Compound of the present invention 5% Bentonite 40% Clay 50% Sodium lignin sulfonate 5% The above are uniformly mixed and pulverized, and after adding water and kneading,
Granulate and dry to obtain granules.

Formulation Example 4 (Dust) The compound of the present invention 3% clay 97% or more are uniformly mixed and pulverized to obtain a dust.

[Examples of herbicides]

Next, the herbicidal effect of the compound of the present invention will be specifically described with reference to Examples.

In the following examples as herbicides, the herbicidal effect against weeds and the phytotoxicity against crops were in accordance with the criteria shown in Table 1.

Example Post-emergent foliar treatment test A plastic tray having a height of 20 cm, a width of 25 cm, and a height of 12 cm was filled with sifted field soil, seeded with various plants, and covered with 1 cm of soil. After that, when the first true leaf of soybean developed, a predetermined amount of the drug was spray-treated on the foliage. After the chemical treatment, the plants were further grown for 3 weeks, and then the herbicidal efficacy and crop phytotoxicity of each plant were investigated. The results are shown in Table 2. The treatment chemical was formulated in a wettable powder, a predetermined amount was dispersed in water (including a spreading agent), and the test was conducted at a rate of 150 liters per 10 ares.

* Compounds described in JP-A-56-36456 ** Compounds described in U.S. Pat. No. 4,334,912

Claims (3)

[Claims] 1. N '-[2- (4-Isopropylphenoxy) pyridyl-5] -N-methoxy-N-methylurea. 2. A herbicide containing N '-[2- (4-isopropylphenoxy) pyridyl-5] -N-methoxy-N-methylurea as an active ingredient. 3. The herbicide according to claim 2, which is a selective control agent for upland weeds.