KR810000602B1 - Method for preparing N- (1, 3, 4-thiadiazol-2-yl) benzamide - Google Patents

Abstract

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Description

Method for preparing N- (1,3,4-thiadiazol-2-yl) benzamide

The present invention relates to a process for the preparation of N- (1,3,4-thiadiazol-2-yl) -benzamide of formula (I) which is useful as an insecticide.

R in the above formula

X is oxygen or sulfur and if one of R ¹ and R ² is hydrogen the other is fluorine atom, chlorine atom, bromine atom, trifluoromethyl or methoxy and if one of R ³ and R ⁴ is hydrogen the other If oxy or trifluoromethyl and one of R ⁵ and R ⁶ is hydrogen, the other is chlorine, bromine, fluorine, trifluoromethyl or hydrogen and if one of R ⁷ and R ⁸ is hydrogen the other Or alkoxy having 1 to 2 carbon atoms substituted with more fluorine atoms.

Since pest control is one of the important tasks for agrochemicals, research on this area has been continued. Many types of pests are contaminated with many types of crops, causing unsanitary conditions and pollution. Insect damage is enormous and therefore pest control has emerged as an essential prerequisite.

In recent years, the development of new and excellent pesticides has led to the disappearance of conventional pesticides.

Compounds of formula (I) are novel substances in organic chemistry. However, there have been reports of related compounds in the prior art. For example, US Pat. No. 3,726,892 discloses manufacturable 1,3,4-thiadiazol-2-yl urea by Cevalo. Lao (see Indian J. Chem. 8, 509-13 (1970)) taught the synthesis of 2-amino-1,3,4-thiadiazole, an intermediate of the compounds of the present invention.

US Patent 3,748,356 discloses the herbicidal and pesticidal effects of N-benzoyl-N'-phenyl-urea by Wellinger and Mulder.

일 경우에는 탈수제로, E가 R-CN=N-일 경우에는 산화제로 폐환시킴을 특징으로 하여 구조식(I)의 신규인 티아디아졸일 벤즈아미드를 제조하는 방법을 제공해 준다.The present invention belongs to the field of agrochemicals and the compound of formula (II)

In one case, a dehydrating agent, and when E is R-CN = N- provides a method for producing a new thiadiazolyl benzamide of formula (I) characterized in that the ring is oxidized.

또는 R-CH=N-(R은 상기에서 정의한 바와 같다)이다.E in the above structural formula

Or R-CH = N- (R is as defined above).

Insecticidal methods and insecticidal compositions can also be obtained using the compounds of the invention.

All quantities herein are measured by metric system and temperatures are in degrees Celsius. All proportions and percentages are by weight and halogen refers to fluorine, chlorine, bromine and iodine atoms.

The compound of formula (I) may be prepared by known methods or by similar methods.

일 경우는 탈수제로, E가 R-CH=N-일 경우는 산화제로 폐환시켜서 제조할 수 있다.A compound of formula (I), wherein R is as defined above,

In this case, the dehydrating agent may be used, and when E is R-CH = N-, the oxidizing agent may be closed.

Effective dehydrating agents include phosphoric acid, formic acid, phosphorus pentachloride, phosphorus pentoxide and benzoin and alkanophosphate chlorides and acid anhydrides in the presence of strong acids. Preferred dehydrating agents are strong acids, in particular methanesulfonic acid and concentrated sulfuric acid.

The dehydrating ring closure is carried out at a temperature of 20 ° to 80 ° C., preferably at room temperature. Solvents such as halogenated benzenes, halogenated alkalis, dichlorobenzenes, chloroform and methylenedichloride may be used if necessary, including chlorobenzene, but it is usually preferable to carry out the reaction without adding a solvent.

Preferred oxidants may use strong oxidants such as ferric chloride or calcium ferricyanide. The oxidative ring closure is preferably brought about in lower alkanols such as ethanol or propanol at the reflux temperature of the reaction mixture. Generally, however, temperatures between 50 ° and 100 ° C are used where necessary.

As the organic chemist acknowledges, all starting compounds used to prepare the compound of formula (I) can be obtained by conventional techniques.

In all examples, the compounds were identified for nuclear magnetic resonance analysis, elemental microanalysis and in some cases by infrared analysis and mass spectrometry.

The following preparations and examples illustrate a typical ring closure with a dehydrating agent.

[Preparation 1]

[1- (4-Pentafluoroethoxybenzoyl) -4- (2,6-dimethoxybenzoyl) -thio-semitabazide]

0.54 g of ammonium thiocyanate is added to 10 ml of tetrahydrofuran, the mixture is heated to reflux and a solution of 1.5 g of 2,6-dimethoxybenzoyl chloride in 10 ml of tetrahydrofuran is added thereto. The mixture was stirred at reflux for 20 minutes, cooled to ambient temperature and a solution of 1.5 g of 4-pentafluoroethoxybenzoyl hydrazine dissolved in 20 ml of tetrahydrofuran was added dropwise. After stirring the reaction mixture at ambient temperature for 1.5 hours, the mixture was evaporated to dryness in vacuo and the residue was washed with diethyl ether. The ether is removed by evaporation in vacuo and the product is recrystallized to give 1.1 g of the compound of the above name. Melting Point 183 ~ 186 ℃

Example 1

[N- [5- (4-pentafluoromethoxyphenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide]

1 g of the intermediate prepared in Preparation Method 1 was slowly added to 5 g of methanesulfonic acid, and the mixture was stirred at ambient temperature for 5 hours. The mixture is poured slowly into 100 g of ice and stirred thoroughly. The pH of the aqueous mixture is adjusted to 8.5 by the addition of concentrated ammonium hydroxide, whereupon the solids are collected and recrystallized from aqueous ethanol to give 0.6 g of impure product. The product is purified by chromatography on silica gel using a solvent of 70% toluene and 30% ethyl acetate. The purified product is 200 mg of the product of the above name.

Example 2

[N- [5- (4-trifluoromethoxyphenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide]

A compound of the above name by reacting with 1- (4-trifluoromethoxybenzoyl) -4- (2,6-dimethoxybenzoyl) -thiosemicarbazide as a starting material and reacting with methanesulfonic acid using the process of Example 1. Get

Example 3

[N- [5- (6-methoxy-2-benzo [b] furyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxy benzamide]

1- (6-methoxy-2-benzo [b] furylcarbonyl) -4- (2,6-dimethoxybenzoyl) thiosemicarbazide was reacted with methanesulfonic acid according to the process of Example 1 Obtain the product.

Example 4

[N- [5- (2-indenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxy benzamide]

The 1- (2-indenocarbonyl) -4- (2,6-dimesbenzoyl) thiosemicarbazide is reacted with methanesulfonic acid according to the process of Example 1 to obtain a product of the above name.

Example 5

[N- [5- (5-methoxy-2-benzo [b] furyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxy benzamide]

The methanesulfonic acid was reacted with 1- (5-methoxy-2-benzo [b] furylcarbonyl) -4- (2,6-dimethoxybenzoyl) thiosemicarbaside according to the process of Example 1 To get the product.

Example 6

[N- [5- (5-trifluoromethyl-2-benzo [b] furyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxy benzamide]

According to the process of Example 1, 1- (5-trifluoromethyl-2-benzo [b] furylcarbonyl) -4- (2,6-dimethoxybenzyl) thiosemicarbaside was methanesulfone Reaction with an acid gives a product of the above name.

Example 7

[N- [5- (6-trifluoromethyl-2-benzo [b] furyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxy benzamide]

By reacting 1- (6-trifluoromethyl-2-benzo [b] furylcarbonyl) -4- (2,6-dimethoxybenzoyl) thiosemicabaside with methanesulfonic acid according to the process of Example 1 Obtain the product named.

Example 8

[N- [5- (5-fluoro-2-benzo [b] furyl-1,3,4-thiadiazol-2-yl] -2,6-dimethoxy benzamide]

According to the process of Example 1, 1- (5-fluoro-2-benzo [b] furylcarbonyl) -4- (2,6-dimethoxybenzyl) thiosemicarbaside was reacted with methanesulfonic acid to give Obtain the product.

In order to determine the pesticidal effect of the compound of formula (I), experiments were conducted on live pests. The results were obtained by the following test method, and in most cases, the values obtained by repeating the application rates were repeated. The compound is the product according to Example No.

[Exam 1]

[Examination for Mexican Legume Beetles and Giant Salt Beetles]

Compounds to be used for the test were prepared by dissolving 10 mg of the compound in 1 ml of a solvent of anhydrous ethanol acetone 1: 1 containing oxymal R23g and oxymal S13g per liter, respectively. (Toxymal is a trade name for a sulfonate / nonionic mixed surfactant manufactured by Stefan Chemicals, Inc., Northfield, Illinois, USA). Each sample was dispersed in 9 ml of water so that the concentration of the test compound was 1000 ppm.

If necessary, the dispersion is diluted with water to a low concentration. Spray the dispersion evenly over 10 days old legumes, leave it to dry, then remove the leaves from the plant and wrap the edges of the cut leaves with a cotton soaked in water. Five leaves of two or three stages of Maxican soybean and beetle larvae and two or three stages of Spodoptera eridania in plastic Petra dishes of 100 mm diameter. Put each one. Three identical petri dishes are used for each compound. The dish is placed at 25 ° C. and 51% relative humidity for 4 days and then the pesticidal effect is evaluated. Several dishes were evaluated after being placed for 3 days or more in a controlled condition.

Insecticidal effect was evaluated by the following index in comparison with the solvent treatment and no treatment.

0 = not controlled

1 = 1-7 larvae killed

2 = 8-14 larvae killed

3 = kill 15 larvae

The following table records the results of the test compounds.

TABLE 1

The compound was tested in the same manner, except that the application rate was tested differently and the larvae of dead pests were evaluated as killing percentages. In the caterpillar larval test, 100% of the compounds were killed at 5 ppm on day 4 and 100% were killed on day 7 at 2.5 ppm. In the Mexican bean beetle test, 100% was killed at 4 ppm at 5 ppm and 80% at 7 ppm at 2.5 ppm.

The above measurement showed a strong insecticidal effect of the compound of formula (I). Entomologists will recognize that the compounds have a wide range of effects on the control of pests belonging to several orders that adversely affect humanity and economics.

For example, the compound can control the following pests.

Beetles: Antonomus gradnis, Crambus caliginosellus, Oulema melanopus, Leptinotarsa decemlineata, Hypera posta postica, Antremus Scrophulariae, Tribiumium Confusum, Lyctidae species, Agriotes species, Sitophilus Oryzae), Nodonota puncticollis and Contrachelus neruphar,

Flywood: Musca domestica, St omoxys calcitrans, Haematobia irritans, Formia regina, Hylemya brassicae ), And Psila rosae,

Lepidoptera: Laspeyresia pomonella, E rxoa, Plodia interpunctella, Tartri cidae, Heliothis zea, Austria Ostrinia nubil alis, Hellula rogatalis, Trichoplusia ni, Thyridopteryx ephemeraeformis Malacosoma americanum And Spod optera frugiperda,

Locust: Blatella germanica, Periplaneta americana.

The compound of the present invention is effective in reducing the herd of pests and is also used in the method of reducing the herd of pests by treating an effective insecticidal amount with the compound to the substance to be consumed by the pest.

Treat the compound with a substance that the pest ingests and induce the pest to consume the compound. For example, by treating the compound on the part of the plant, especially the leaf, ingested by the pest, the pest gathered in the plant can be easily controlled. Pests that consume crops, paper, and wood products are easily controlled by treating the compounds with these products. The compound can also be effectively used for protecting stored grain or seeds.

It is also noteworthy that ingesting the compound into pests interferes with the growth stage of the pest. For example, ingesting the compound into adults produces eggs that have no significant effect but cannot ovulate. If the larvae consume this compound, they will die without being transformed into the next larvae. The larvae of the last stage ingesting the compound die in the pupal form.

Entomologists may find that the use of compounds of formula (1) does not result in pest destruction. Of course, in some cases, the entire pest is killed, but only some of the pests are killed, and some pests can survive the treatment of this compound. Entomologists vary the amount of pests killed by insect species, compound used, application rate, insect growth, climate and other factors. Thus, the term "reduction of pest groups" means that the number of surviving pests is reduced, which is the amount by which the herds of treated pests disappear, sometimes or in all cases.

Of course, the amount of reduction of pests varies depending on the type of the compound and the application rate of the compound. In all cases, at least a pesticidal effective amount should be used. "Pesticide effective amount" means an amount sufficient to induce a reduction in the amount of pests treated. In general, the effective amount of insecticide is 1 to 1000 ppm.

The application rate of the pesticide is measured by the pesticide concentration in the dispersion used normally. The application rate is measured in this way because it is most convenient to use an amount sufficient for the leaf or other material to be treated as a thin film of dispersion. Since the amount of dispersion used depends on the surface area of the edible substance to be treated, the amount of compound also depends on the concentration in the dispersion.

Dispersions of the present compounds in use are made of typical pesticidal compositions but are novel because of the presence of new compounds of the invention. A small amount of concentrated pesticidal composition is mixed with a suitable amount of water to produce the desired concentration of compound, which aqueous dispersion is very widely effective. Generally, such concentrated aqueous dispersion compositions containing 5 to 90% of the present compounds are usually prepared in the form of emulsion concentrates, wetting agents or suspensions.

A hydrating agent is the incorporation of the active compound into an inert carrier which is a mixture of a fine inert powder and a surfactant. The concentration of active compound is generally 10 to 90% by weight. Inert powders are typically selected from attapulgite clays, m ontmorillonite clays, diatomaceous earth or purified silicates. Effective surfactants containing 0.5 to 10% in the hydrating agent are selected from nonionic surfactants such as sulfonated lignin, concentrated naphthalene sulfonates, naphthalene sulfonates, alkylbenzenesulfonates, alkylsulfates and ethylene oxide additives of alkylphenols. do.

Typical emulsion concentrates of this compound contain 50 to 500 g of compound per liter of liquid equivalent to 5 to 50% and are dissolved in an inert carrier which is a mixture of a water immiscible organic solvent and an emulsion. Effective organic solvents are high boiling point naphthalene and olefin fractions of petroleum such as aromatic compounds, in particular xylene, petroleum fractions, especially heavy aromatic naphthas. Organic solvents such as rosin derivatives and terpenes, and alcohol complex compounds such as 2-ethoxyethanol can also be used. Suitable emulsions used in emulsion concentrates are selected by using the same surfactants and the same concentrations as those used in the hydrating agent.

Suspensions of a compound containing a concentration of the present compound in the form of a fine powder similar to that of the emulsifier concentrate are suspended in a suitable nonsolvent liquid. At the most suitable cost, the liquid is a mixture of water and surfactant.

The same surfactants used for the hydrating agent are used for the preparation of the suspension. In many cases small amounts of active diluents are used to enhance suspension. Such inert carriers are swellable clays such as attapulgite, montmorillonite, starch and especially purified silicates.

It can be used in the form of a liquid in which the present compound is added to a suitable organic solvent, usually a petroleum oil such as a dispersion oil widely used in agrochemicals.

Furthermore, the compounds can be used as compositions in the form of powders and aerosol formulations. The powder contains a fine powdered compound in which the powder is dispersed in an inert carrier.

Carrier generally refers to powdered clay, such as foliarite, bentonite, burn pressure or montmorillonite. Powders generally contain 0.1 to 10% of the present compound.

The aerosol composition dissolves or disperses the compound of formula (I) in an inert carrier which is a pressure generating propulsion mixture and packs the mixture through a spray valve into the vessel blade. The propellant mixture contains a low boiling halocarbon that can be mixed with an organic solvent or an aqueous suspension pressurized with an inert gas or gaseous hydrocarbon.

Claims (1)

Where the compound of formula (II)

The method for preparing a new thiadiazolyl benzamide of formula (I), characterized in that as a dehydrating agent in one case, and ringing with an oxidizing agent when E is R-CH = N-.

R in the above formula

X is oxygen or sulfur and if one of R ¹ and R ² is hydrogen the other is fluorine atom, chlorine atom, bromine atom, trifluoromethyl or methoxy and if one of R ³ and R ⁴ is hydrogen the other If oxy or trifluoromethyl and one of R ⁵ and R ⁶ is hydrogen, the other is chlorine, bromine, fluorine, trifluoromethyl or hydrogen and if one of R ⁷ and R ⁸ is hydrogen the other Or alkoxy having 1 to 2 carbon atoms substituted with more fluorine atoms and E is

Or R-CH = N- (R is as defined above).