IL31427A - Pyrancarboxylic acid anilides,process for their manufacture and their use as plant fungicides - Google Patents

Description

PYRANCARBOXYLIC ACID ANILIDESi PROCESS FOB THEIR MANUFACTURE AND TH IR USE AS PESTICIDES Pyjniinear-boKylnlo ticirl runllidea,—piuuU y For tftelT- The present invention relates to 2-rethyl-5 » 6-dihydro-pyran-3-carboxylic acid anilides of the general formula I in which R stands for hydrogen, a methyl group or methoxy group, the substituents being in meta, ortho or para-position of the benzene nucleus.

The present invention also relates to plant protecting agents containing the aforesaid carboxylic acid anilides (i) as active ingredient.

It is known that compounds of similar constitution such as 2 , 3-dihydro-5-carboxanilido-6-methyl- 1 , ¾-oxathiine (il) and 2 , 3-dihydro-5-carboxanilido-6-methyl- 1 , ¾-oxathiine-U dioxide (ill) have fungicidal action (cf. U.S. Patent 3.24 .^99 and Belgian Patent 679, 8¾, pages 19 and 29).

(II) (III) Known compound (il) has good action against smut but minor systemic action only against rust. Known compound (ill) has good systemic and seed treating effects, but no prophylactic action against rust and an unsatisfactory action in the treatment of smut.

The novel compounds of formula I are superior to known compounds II and III. With respect to known compound II the superiority is especially pronounced in the systemic effect and the seed treating effect and as compared with known compound III the prophylactic action and the action against smut are much better.

Systemic effect means an inner therapeutic effect after the absorption of the active ingredient either by the leaves or by the seeds. After germination of the treated seeds, especially cereals, the active ingredient is transported to other parts of the plant which have not been treated and thus protects the plant against fungus infestation.

A special advantage of the novel compounds I resides in the fact that they combine the fungicidal properties of known compounds II and III. That means that it is no longer necessary first to apply one known compound and at a later stage of growth of the plant another known compound to prevent infestation with fungi, for example of cereals. One treatment with a novel compound of formula I, either of the seeds or of the plant in an early stage of growth, is sufficient to protect the plant against fungus disease. The novel compounds of formula I are, for example, significantly superior to known compounds II and III in the figth against the soil fungus Rhizoctonia.

Another object of this invention is a process for preparing 2-methyl-5 ♦ 6-dihydropyran-3-carboxylic acid anilides of formula (i) which comprises A) reacting 2-methyl-5 » 6-dihydropyran-3-carboxylic acid with a chlorination agent to yield 2-methyl-5 · 6-dihydropyran-3-carboxylic acid chloride which is then reacted with anilines which may carry appropriate substituents in the presence of an inorganic or tertiary organic base, or B) reacting at elevated temperature 2-methyl- , 6-dihydropy*an- 3-carboxylic acid with phenyl isocyanates which may carry As chlorination agent phosphorus trichloride is preferred. Phosphorus pentachloride, thlonyl chloride and phosphorus oxychloride may also be used. The chlorination is carried out t at a temperature in the range of from -20°C to +100°Cf a temperature range of from 0°C to 30°C being preferred.

The chlorination is suitably carried out in an inert solvent such as carbon tetrachloride, chloroform, methylene chloride, ethylene chloride, toluene or benzene.

The reaction of the acid chloride with anilines optionall carrying methyl or methoxy substituents in meta, ortho or para position of the benzene nucleus is performed in the presence of an inorganic or a tertiary organic base. Suitable inorganic bases are in the first place sodium hydroxide and potassium hydroxide. As tertiary organic bases triethyl amine, dimethyl aniline or pyridine and the homologs thereof may be used. An excess of corresponding aromatic amines- may also be used.

The 2-methyl-5 » 6-dihydropyran-3-carboxylic acid is reacted with phenyl isocyanates optionally carrying methyl or methoxy substituents in the benzene nucleus at a temperature in the range of from 80°C to 180°C, preferably 1U0°C to 170°C. When the reaction is terminated it is expedient to remove excess phenyl ieocyanate from the reaction product by washing it with an inert solvent such as carbon tetrachloride or gasoline. 2-Methyl-5 , 6-dihydropyran-3-carboxylic acid anilides of formula (i) according to the invention are used as active ingredients in pesticides, above all as furgLcides. They are especially effective against rust and smut fungi, for example yellow and brown rust of wheat, smut and stinking smut and soil fungi, for example Rhizoctonia, They can be applied either as plant protecting agents or seed protecting agents.

The active ingredients according to the invention can be used in admixture with the usual solid or liquid inert carrier materials, with adhesive, wetting, dispersing and grinding auxiliaries in the form of wettable powders, emulsions, suspensions, dusts or granules. They can be mixed with other pesticides with which they form compatible mixtures.

Suitable carrier materials are mineral substances such as aluminum silicates, argillaceous earths, kaolin, chalks, siliceous chalks, talcum, kieselguhr, or hydrated silicic acid, as well as mixtures of the said mineral substances with special additives, for example chalk in admixture with sodium stearate. As carrier materials for liquid preparations there can be used all common and suitable solvents, for example toluene, xylene, diacetone alcohol, cyclohexanone , isophorone, gasolines, paraffin oils, dioxane, dimethyl formamide, dimethyl sulfoxide, ethyl acetate, butyl acetate, tetrahydrofurane , chiorobenzene and the like.

As adhesives glutinous cellulose products or polyvinyl alcohols may be used.

Suitable wetting agents are all appropriate emulsifiers such as hydroxyethylated alkyl phenols, salts of aryl and · alkylaryl sulfonic acids, salts of me thyl-taurine , salts of phenylkogasin sulfonic acids or soaps.

Dispersing agents to be used are salts of lignin- sulfonic acid, salts of naphthalene sulfonic acid and possibly hydrated silicic acid or kieselguhr.

As grinding auxiliaries there may be used suitable inorganic or organic salts, for example sodium sulfate, ammonium sulfate, sodium carbonate, sodium bicarbonate, sodium thio- sulfate, sodium stearate or sodium acetate.

The following examples serve to illustrate the invention but they are not intended to limit it thereto. - k - E x a m p l e 1 Ik.2 Grams of 2-methyl-5 f 6-dihydropyran-3-carboxylic acid were dissolved in 70 milliliters of absolute benzene and 8. 5 milliliters of thionyl chloride were added at 22°C. After standing for 2 1 /2 hours the reaction mixture was concentrated to one fourth of the original volume under reduced pressure. The crude acid chloride thus obtained was dropped over a period of θ minutes into a solution of 9 · 3 grams of aniline and 9. 5 grams of pyridine in 100 milliliters of benzene, which solution was stirred at -5°C. The reaction mixture was then stirred for another hour without cooling and finally poured onto ice. The benzenic solution was separated and washed with water. 1 6. 3 Grams of 2-methyl-5 , 6-dihydropyran-3-carboxylic acid anilide were obtained from the dried benzenic solution, corresponding to a yield of 75 $ of the theoretical. After recrystallization from methanol/water with the addition of active charcoal the compound melted at 108 - 109°C.

Analysis: C^H^NOg , molecular weight 217. 26 calculated C 72.0 # H 6.9 9& N 6. h £ found C 72.2 # H 7.0 # N 6.7 # The infrared spectrum of the novel compound showed characteristic peaks at 3.05 ^ΐ, 6.08 u and 6. 13 ^Λτ E x a m p l e 2 14. 2 Grams of 2-methyl-5 » 6-dihydropyran-3-carboxylic acid and 1 1 . 9 grams of phenyl isocyanate (O.1 mole each) were heated for 4 minutes at 160°C. After cooling the crystals were washed with benzene to remove unreacted phenyl isocyanate and the residue was recrys tallized from alcohol/water. 17. 6 Grams of 2-methyl-5 , 6-dihydropyran-3-carboxylic acid anilide were obtained, corresponding to a yield of 81 % of the theoretical. The compound melted at 108 - 109°C.

The analytical data and peaks of infrared spectrum were identical with those of the compound of Example 1 .

E x a m p l e 3 To prepare the 2-methyl-5 » 6-dihydropyran-3-carboxylic acid anilide according to the invention, 0. 1 mole of 2-methyl-5 , 6-dihydropyran-0-carboxylic acid chloride was suspended in milliliters of ethylene chloride, 0, 05 mole of phosphorus trichloride was added and the suspension was allowed to stand for 1 l/5 hours at room temperature, moisture being excluded.

After separation of the phosphorous acid forming the lower liquid layer, the solvent was distilled off under reduced pressure. The crude acid chloride thus obtained was dropped at 0°C into a solution of 0. 1 mole of the respective aromatic amine substituted in the benzene nucleus and 0. 12 mole of pyridine in 100 milliliters of benzene. After standing for one hour at room temperature the reaction mixture was poured into water, the organic phase was washed with dilute hydrochloric acid and water and the solvent was distilled off.

The following compounds were prepared in this manner: a) 2-methyl-5 » 6-dihydropyran-3-carboxylic acid- (m-methylanilide ) using m-toluidine, yield 78 % of the theoretical, calculated on the carboxylic acid used, mej&ting point 6. 5 - 97 · 5°0 , b) 2-methyl-5 » 6-dihydropyran-3-carboxylic acid (o-methylanilide ) using o-toluidine, yield 75 of the theoretical, melting point 128 - 128. °C ' c) 2-methyl-5 , -dihydropyran-3-carboxylic acid (p-methylanilide ) using p-toluidine, yield 80 of the theoretical, melting point 125 - 126°C d) 2-methyl-5 t -dihydropyran-3-carboxylic acid (m-methoxyanilide ) using m-anisidine, yield 73 $ f h a n 1 - 0 °C e) 2-methyl-5 » 6-dihydropyran-3-carboxylic acid (o-methoxyanilide ) using o-anisidine, yield 78 $ of the theoretical, melting point 131 - 132°C f) 2-methyl-5 » 6-dihydropyran-3-carboxylic acid (p-methoxyanilide) using p-anisidine, yield 79 $ of the theoretical, melting point 155 - 156°C.

In the following Examples k to 6 the following compounds were tested: (i) 2-methyl-5 I -dihydropyran-3-carboxylic acid anilide (ll)2,3-dihydro-5-carboxanilido-6-methyl-1 ,¾-oxathiine (ill) 2 , 3-dihydro-5-carboxanilido-6-methyl- 1 , -oxathiine- A,4-dioxide (i) is a novel compound according to the invention (il) is a compound disclosed in U.S. Patent 3,2¾9, 99 (Hi) s a compound disclosed in Belgian Patent 679, 98¾.

E x a m p l e h Wheat (Triticum) was grown in pots and treated in the three leaves stage with compound (i) in concentrations of 7·5ι 15» 30, 60 and 120 milligrams of active ingredient per liter of spray liquor. Each test was repeated four times, i.e. for each concentration k pots each containing 10 wheat plants were used. For comparison there was used untreated wheat and wheat treated with compounds (il) and (ill) in the same concentrations. One day after drying of the coating of active ingredient the plants were infested with, a spore suspension of yellow rust of wheat (Pucclnia strilformis) and placed for 12 hours in a moist atmosphere. After infestation the plants were kept in the greenhouse and evaluated after k weeks. The numbers in the following table indicate the percentage of plants infested with rust with the respective concentration of active ingredient.

Table 1 shows that compound (i) had a better effect than compound (il) and a much better effect than compound (ill).

Down to a concentration of active ingredient of 30 milligrams per liter of spray liquor the plants remained free from infestation. Hence, it follows that for the prophylactic treatment of plants one day before infestation compound (i) of the invention is far superior to known compound (ill).

T a b l e 1 Prophylactic treatment of winter wheat against yellow rust one day before infestation. Evaluation of the effect weeks after infestation.

E x a m p l e 5 Seeds of wheat were treated for 10 minutes with compound (i) in concentrations of 2 0, 125 and 60 grams of active ingredient per 100 kilograms of seeds. For comparison, seeds were treated in the same manner with compounds (il) and (ill) in the same concentrations.

The seeds treated in this manner were sown ^k days after the treatment. After germination of the seeds the plants were artificially infested in the three- to four leaves stage with spores of brown rust of wheat (Puccinia triticina).

The following Table 2 shows that compound (i) in concentrations of 250 and 125 milligrams per 100 kilograms of seeds ensured a full protection against brown rust. Known compound (ill) had a similar effect whereas compound (il), when used in the same concentrations, had no effect at all. Hence, it follows that compound (i) is far superior as seed treating agent to known compound (il).

T a b l e 2 Seed treatment of winter wheat Wheat was grown in pots and treated in four repetitions in the two leaves stage with compound (i) with concentrations of 250, 125, 60, 30 and 15 milligrams of active ingredient per liter of spray liquor. For comparison, compounds (il) and (ill) were used in the same manner and some plants were not treated.

Seven days after spraying with the spray liquor the treated leaves were carefully cut off. Five weeks thereafter the newly grown leaves, which had not been treated with the active ingredient, were infested with a suspension of spores house. Three weeks after infestation the plants were evaluated.

The following Table 3 shows that compound (i) had a good, systemic action against the infestation which was approximately equal to the action of known compound (ill) . Known compound (ll) exhibited a very weak systemic action only. Hence, it follows that compound (i) is surprisingly superior to known compound (ll) .

T a b l e 3 Systemic action against brown rust of wheat E x a m p l e 7 Plants of wheat grown in pots in the greenhouse were treated in the two leaves stage with the following compounds according to the invention with concentrations of k00f - 200 , 1 00 and 50 milligrams of active ingredient per liter of spray liquor.

(A) 2-methyl-5 » 6-dihydropyran-3-carboxylic acid- (m-methylanilide ) (B) 2-methyl- , 6-dihydropyran-3-carboxylic acid- (o-methyl- ■ anilide) (C) 2-methyl-5 , 6-dihydropyran-3-carboxylic acid- (p-methyl- anilide) (D) 2-methyl-5 6-dihydropyran-3-carboxylic acid- (m-methoxy- anilide) (E) 2-methyl-5 6-dihydropyran-3-carboxylic acid- (o-methoxy- anilide) (F) 2-methyl-5 » 6-dihydropyran-3-carboxylic acid- (p-methoxy- anilide).

In the same manner and with the same concentrations the following compounds known as fungicides were used for comparison: (ll) , 3-dihydro-5-carboxanilido-6-methyl- 1 , 4-oxathiine and (IV) zinc-ethylene-bis-dithiocarbamate . Control plants were treated with tap water without active ingredient.

Five days after the treatment the two treated leaves were cut off at the basis. Five weeks thereafter the newly grown leaves were strongly infested with a suspension of spores of black rust of wheat (Puccinia graminis), the plants were kept for 12 hours in a moist atmosphere and then brought into a greenhouse. Three weeks after infestation the plants were evaluated.

The following Table shows that compounds (A) to (F) according to the invention had an excellent systemic effect against rust of wheat which was superior to the effect of known compound (il). Compound (iv) used for comparison had no systemic effect.

T a b 1 e k compound $ of black rust of wheat after treatment with milligrams of active ingredient per liter of spray liquor oo 200 100 50 (F) 0 0 15 25 (II) 10 35 60 100 (IV) 100 100 100 100 untreated 100 100 100 100 E x a m p l e 8 Seeds of wheat of the type "Heine VII" were treated in a drum for 10 minutes in usual manner with compounds (A) to (F) according to the invention (cf. Example 7) in concentrations of 200, 100 and 0 grams of active ingredient per 100 kilograms of seeds. For comparison, some of the seeds were treated in analogous manner with known compound (il). The seeds were sown I k days after the treatment. After germination the plants were infested in the three and four leaves stage with spores of yellow rust of wheat (Puccinia striiformis ) ..

Four weeks after infestatio the plants were examined and the degree of infestation was determined.

The following Table 5 shows that compounds (A) to (F) according to the invention had a very good systemic action against yellow net when used as seed treating agent. Under the indicated conditions , comparative compound (il) did not exhibit any effect.

T b l e 5 compound % of infestation with yellow rust of wheat after treatment with grams of active ingredient per 100 kilograms of seeds 200 100 50 E x a m p 1 e 9 Oat seeds of the type "Fltimingstreue" were strongly infested with spores of loose smut of oats (Ustilago avenae). The infested seeds were treated in usual manner for 10 minutes in a drum with compounds (A) to (F) according to the invention in concentrations of 100, 50 and 25 grams of active ingredient per 100 kilograms of seeds. For comparison, part of the seeds were treated with the known 2 , 3-dihydro-5-carboxanllido-6- methyl- 1 , ¾-oxathiine-4-dioxide (ill) in the same concentr- ations. The seeds were sown Ik days after the treatment.

After formation of the panicles the plants were examined as to the infestation with smut.

The following Table 6 shows that compounds (A) to (F) according to the invention had a distinctly better effect against loose smut of oats than comparative compound (ill). compound $ of infestation with loose smut of oats after treatment with grams of active ingredient per 100 kilograms of seeds 100 50 25 (A) 0 0 0 (B) 0 0 0 (C) 0 0 5 (D) 0 0 3 (E) 0 5 1 5 (F) 0 0 5 (III) 0 12 35 untreated 68 71 6k E x a m p 1 e 10 Winter wheat of the type "Heine VII" was treated in the three leaves stage with compounds according to the invention (i) 2-methyl-5 f 6-dihydropyran-3-carboxylic acid anilide and (A) 2-methyl-5 » 6-dihydropyran-3-carboxylic acid- (m-methyl- anilide) and with known compounds (il) 2 , 3-dihydro-5-carboxanilido-6-methyl- 1 , -oxathiine and ( III) 2 , 3-dihydro-5-carboxanilido-6-methyl- 1 , -oxathiine- 4 , -dioxide in concentrations of 1 20 , 60, 30 » 15 » and 7 · 5 milligrams of active ingredient per liter of spray liquor. Control plants were sprayed with water only.

After drying of the coating of active ingredient the plants were infested with a spore suspension of yellow rust of wheat and placed for 12 hours in a moist stmosphere. Four weeks after infestation the plants were examined as to the infestation with yellow rust. The result indicated in the following Table a distinctly better effect in the same concentrations than known compound (ll). As compared with compound (ill) the effect is still more pronounced. a b l e 7 Prophylactic treatment of winter wheat against yellow rust one day before infestation. Evaluation of the effect four weeks after infestation E x a m p l e 1 1 Cottonseed (Gossypium) freed from lint by means of acid and infested with Rhizoctonia solani was mixed for 10 minutes in a drum with compounds (A) and (i) of the invention specified in Example 10 and with compounds (ll) and (ill) also specified in the said example in concentrations of 1 60 , 80 , 40 , 20 and 1 0 grams of active ingredient per 100 kilograms of seeds Control seeds remained untreated. The seeds were kept for Z hours in a closed box and then sown in four repetitions, each time 1 00 grains, in garden mould also infested with Rhizoctonia solani.

Four weeks after germination the plants were examined as to their infestation with the soil fungus. The following Table 8 in which the avera e values of infestation are given, shows that compounds (i) and (A) according to the invention were signi icantly superior to the known comparative compounds (II) and (ill).

T a b l e 8 Treatment of cottonseed, evaluation four weeks after infestation E x a m p l e 12 Seeds of winter wheat were mixed for 10 minutes in a drum with compounds (i) and (A) of the invention specified in Example 10 and with known compounds (ll) and (ill) in concentrations of 100, 75, 50 and 25 grams of active ingredient per 100 kilograms of seeds. Part of the seeds remained untreated for a control test. 10 Days after the treatment the seeds were sown in garden mould. For each concentration and active ingredient four times 100 seed grains were sown.

After germination of the wheat the plants were artificially infested in the three to four leaves stage with spores of brown rust of wheat. Four weeks after infestation the treated plants and the untreated control plants were examined.

The following Table 9 shows the average results of the examination. It can be seen that compounds (i) and (A) of the T a l e 9 Seed treatment of winter wheat?infestation with brown rust of wheat after germination

Claims (1)

1. What is claimed is: 1) 2-Methyl-5 » 6-dihydropyran-3- carboxylic acid anilides of the general formula I 0 in which R stands for hydrogen, a methyl group or a methoxy group substituting the meta, ortho or para position of the benzene nucleus. 2) 2-Methyl-5 » 6-dihydropyran-3-carboxylic acid anilide. 3) 2-Methyl-5 » 6-dihydropyran-3-carboxylic acid-(m- methylanilide) . ) 2-Methyl-5 , 6-dihydropyran-3- carboxylic acid- (o-methyl- anilide. 5) 2-Methyl-5 , -dihydropyran-3-carboxylic acid- (p-methyl- anilide ) . 6) 2-Methyl-5 » 6-dihydropyran-3-carboxylic acid- (m-methoxy-anilide ) . 7) 2-Methyl-5 , 6-dihydropyran-3-carboxylic acid- (o-methoxy-anilide ) . 8) 2-Methyl-5 » 6-dihydropyran-3-carboxylic acid- (p-me thoxy-anilide ) . 9) process for preparing 2-Methyl-5 , 6-dihydropyran- 3-carboxylic acid anilides of the general formula I 0 in which R stands for hydrogen, a methyl group or a methoxy group substituting the meta, ortho or para position of the benzene nucleus, which comprises reacting A) 2-methyl-5 » -dihydropyran-3-carboxylic acid with a chlorination .!■" agent to yield 2-raethyl-5 » 6-dihydropyran-3-carboxylic acid chloride and reacting the said acid chloride with anilines carrying corresponding substituents in the presence of an inorganic or tertiary organic base or B) reacting at elevated temperature 2-methyl-5 » 6-dihydropyran- 3-carboxylic acid with phenyl isocyanates optionally carrying corresponding substituents. Plant fungicides 10) 4'©A>de«e- containing as active ingredient 2-methyl- 5 , 6-dihydropyran-3-carboxylic acid- (ό-methylanilide) in combination with a solid or liquid carrier material, adhesive, wetting, dispersing and/or grinding auxiliary. Plant fungicides 1¾) Pr»p,†i.rid*,m containing as active ingredient 2-methyl- 5 , 6-dihydropyran-3-carboxyllc acid- (p-me thylanilide ) in combination with a solid or liquid carrier material, adhesive, Plant fungicides 15) JJee-tkoAde-s- containing as active ingredient 2-methyl- 5 » 6-dihydropyran-3-carboxylic acid- (m-methoxyanilide ) in combination with a solid or liquid carrier material, adhesive, wetting, dispersing and/or grinding auxiliary. 16) J i as active ingredient 2-methyl- 5 , 6-dihydropyran-3-carboxylic acid- (o-methoxyanilide ) in combination with a solid or liquid carrier material, adhesive, wetting, dispersing and/or grinding auxiliary. Plant fungicides 17) ■ΓΌο i-oite-e- containing as active ingredient 2-methyl- 5 , 6-dihydropyran-3-carboxylic acid- (p-methoxyanilide ) in combination with a solid or liquid carrier material, adhesive, wetting, dispersing and/or grinding auxiliary.