CA1162570A

CA1162570A - Alkylphosphonites, processes for producing them, and the use of alkylphosphonites as fungicides

Info

Publication number: CA1162570A
Application number: CA000375758A
Authority: CA
Inventors: Ludwig Maier
Original assignee: Ciba Geigy Investments Ltd
Current assignee: Novartis AG
Priority date: 1980-04-21
Filing date: 1981-04-16
Publication date: 1984-02-21
Also published as: PT72886A; PT72886B; AU6961081A; EP0038778A3; IL62662A0; ES501535A0; BR8102392A; JPS56166106A; ZA812543B; GR75593B; ES8203387A1; EP0038778A2

Abstract

Abstract There are described fungicidal compositions containing as active ingredient an alkylpho5phonite of the formula RPH(O)OX (I) wherein R is C1-C4-alkyl, and X is hydrogen, C1-C4-alkyl or an ammonium ion, a hydrezinium ion or a metal ion of the first to fourth main group or of the first to eighth subgroup, with the valencies belonging to it. They have for practical purposes a very good curative, preventive and systemic action for the procection of cultivated plants, without affecting these by uncesirable side-effects.
Furthermore, a group of novel compounds embraced by the formula I is described, and also the production thereof.

Description

1 ~ 6257Q

Case 5-12811/-Alkylphosphonites, processes for producing them, and theuse of alkylphosphonites as fun~icides The present invention relates to fungicidal compositions containing as at least one active ingredient an alkyl-phosphonite of the formula I
RPH(O)OX (I) wherein R is Cl-C4-alkyl, and X is hydrogen, Cl-C4-alkyl or an ammonium ion, a hydrazinium ion, or a metal ion of the first to fourth main group or of the first to eighth subgroup, with the valencies belonging to it, together with one or more suitable carriers, and to the use of these compounds of the formula I for combating and/or for preventing infestation by fungi.
Alkyl denotes here and in the following: methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl or tert-butyl. Suitable metal ions are, inter alia, the cations of the following elements: alkali metals, such as lithium, sodium or potassium; alkaline-earth metals, such as magnesium, calcium, strontium or barium; elements of the first to eighth subgroups, such as chromium, manganese, iron, cobalt, nickel, copper, zinc, silver or mercury, especially iron, manganese, copper and zinc; elements of the third and fourth main group, such as aluminium, silicon, tin or lead, particularly aluminium, the metal ions present 1~6~5'~0 in the salts and complexes of the formula I having the valencies belonging to them.
Ammonium ions are for example: NH4, NH(alkyl)3, NH2(alkyl)2 and NH3(alkyl), such as NH(C~3)3, NH(C2~5)3,

2(CH3)2~ NH2(C3H7-n~2~ NH3CH3 and NH3C4H9-n, or quaternary ammonium ions, such as tetraethyl-, tetrapropyl-, tetrabutyl-, tetrapentyl-, tetrahexyl-, tetraheptyl-, tetraoctyl-, tetranonyl-, tetradecyl-, methyltributyl-, dimethyldibutyl-, trimethylbutyl-, methyltrioctyl-, benzyltrime~hyl-, benzyltriethyl-, benzyltripropyl-, benzyltributyl-, benzyldimethylhexadecyl-, benzyldiethyl-hexadecyl-, diisobutyl-cresoxyethyl-dimethylbenzyl-, trimethylphenyl-, diphenylmethyl-, butyltripropyl-, tributylphenyl- or tricaprylmethyl-ammonium. Suitable hydrazinium ions are unsubstituted and substituted hydrazini~m compounds, such as NH2NH3, NH2N(alkyl)3, NH2NH(alkyl)2, NH2NH2(alkyl), and so forth.
Alkylphosphonites of the formula I exhibit a valuable fungicidal spectrum, and can be used in particular against phytopathogenic fungi for the protection of cultivated plants, without these plants suffering damage. The preferred compounds include the salts of the formula I.
Especially preferred on account of their good fungicidal action are the metal salts, particularly the aluminium, manganese and copper salts of the formula I, in particular the aluminium and manganese salts. A valuable group of fungicides comprises the lower alkylammonium salts of the formula I. Individual compounds especially preferred are:
aluminium-tris-(ethylphosphonite), O-ethyl-methylphos-phonite, manganese-bis-(ethylphosphonite), copper-bis-(ethylphosphonite) and aluminium-tris-(methylphosphonite.
The production, chemical and physical properties of alkylphosphonic acids, and of the salts and esters thereof are in general known. Reference is made in this respect to Organic Phosphorus Compounds, ed. G.M. Kosalopoff and L. Maier, John ~iley and Sons, New York, N.Y., Vol. 4, 260-462 (1972), and to the literature cited therein. The biological properties of these compounds have not been known hitherto.
Alkylphosphonic acids can be produced by a whole series of methods, for example by a method analogous to that of F. Guichard, Ber., 32, 1572 (1899) by hydrolysis of alkali dihalophosphines of the formula RPX2, wherein R
has the meaning given under the formula I, and X is halogen, especially chlorine or bromine, with splitting-off of corresponding hydrohalic acids:
R-PX2 + 2H20 ~ (I) + 2HX
When water is replaced in the above reactions by a Cl-C4-alkanol of the formula RlOH, wherein Rl is Cl-C4-alkyl [G.M. Kosolapoff, J. Amer. Chem. Soc., 72 (1950)], there can be produced, by analogous alcoholysis, the corresponding esters of the formula I
R-PX2 + 2RlOH -----~' (I) + Rl-X + HX
The alkali metal and alkaline-earth metal salts of the formula I are ob~ained, in a manner known per se, by neutralisation of the free alkylphosphonic acid of the formula I, wherein R is hydrogen, with the equivalent amount of the corresponding alkali metal hydroxide or alkaline-earth metal hydroxide.
A narrower group of alkylphosphonites of the formula I
is novel. This s~bgroup of the formula R'PH(O)OX' wherein R' is Cl-C4-alkyl, and X' is an ammonium ion, a hydrazinium ion or a metal ion of the third and fourth main groups or of the first to the eighth subgroups, is to be designated here and in the following as Ia.

The present invention hence relates also to the compounds of the subgroup Ia and to the production thereof.
Compounds of the formula Ia are produced according to the invention, in the case of the ammonium and hydrazini~lm salts, a) by reaction of an alkylphosphonic acid of the formula R'PH(O)OH, wherein R' is Cl-C4-alkyl, with the equivaLent amount of an amine or of a hydrazine; or b) by reaction of an alkyl ester, preferably a lower alkyl ester, of an alkylphosphonic acid of the formula K'PH(O)OH, wherein R' is Cl-C4-alkyl, with an ammonium or hydrazinium halide, preferably chloride or bromide, with splitting-off of the corresponding alkyl halide; or c) by reaction of an alkylphosphonic acid alkyl ester of the formula I with a tertiary amine to effect quaternisation;
or in the case of the metal salts of the subgroup elements and of the main group elements of the third and fourth main group:
d) by reaction of an alkylphosphonic acid alkyl ester of the formula I with a metal halide, or by reaction of an alkali metal salt of the formula I with a sulfate~ nitrate or halide, preferably chloride or bromide, of the main group or subgroup element.
In the case of all processes, the use of solvents or diluents inert to reaction is advantageous, but is not absolutely necessary. Water can in some cases be used in place of the customary organic solvents. The usual solvents and diluents are for example: aliphatic and aromatic hydro-carbons, such as benzene, toluene, xylenes or petroleum ether; halogenated hydrocarbons, such as chlorobenzenes, methylene chloride 9 ethylene chloride, chloroform or tetra-chloroethylene; ethers and ethereal compounds, such as dial~yl ether (diethyl ether, diisopropyl ether, tert-I 1 ~2570 butylmethyl ether, and so forth), anisole, dioxane ortetrahydrofuran; nitriles, such as acetonitrile or propionitrile, and mixtures of solvents of this kind.
The reaction temperatures are in general between 0 and +180C, preferably between 20 and 150C, mild reaction temperatures being preferred in some cases on account of the disproportionation tendency of the present class of compounds.
All starting compounds are known or are produced by methods known per se.
Fungicides based on alkylphosphite are described in the German Offenlegungsschrift No. 2,456,627, including also the commercial product of the formula ( o~ 0)3 Compared with these alkylphosphite derivates, the compounds of the formula I of the present invention have the advantage that by virtue of the absence of the O-O-alkyl bond they are less readily hydrolysed and consequently their action is more prolonged.
It has been found that compounds of the formula I
surprisingly exhibit a very favourable microbicidal spectrum for practical requirements. They can be used for example for the protection of cultivated plants.
~ he main field of application for compounds of the formula I is that of combating harmful microorganisms, particularly phytopathogenic fungi. The compounds of the formula I thus have for use in practice a very favourable curative, prevent:ve and systemic action for protecting cultivated plants, without these being affected by undesirable side-effects. Cultivated plants within the 1 1 ~257~1 scope of the present inventlon are for example: cereals:
(wheat, barley, rye, oats, rice); beet: (sugar beet and fodder beet); pomaceous fruit, stone fruit and soft fruit:
(apples, pears, plums, peaches, almonds, cherries, strawberries, rasberries and blackberries); legumes: (beans, lentils, peas and soyabean); oil plants: (rape, mustard, poppy, olives, sunflowers, coco, castor-oil plants, cocoa and groundnuts); Cucurbitacea: (pumpkins, cucumbers and melons); fibre plants: (cotton, flax, hemp and jute);
citrus fruits: (oranges, lemons, grapefruit and mandarins);
varieties of vegetables: (spinach, lettuce, asparagus, varieties of cabbage, carrots, onions, tomatoes, potatoes, and paprika); or plants such as maize, tobacco, nuts, coffee, sugar beet, tea, grapevines, hops, bananas and natural rubber plants, and also ornamental plants.
Microorganisms occurring on plants or on parts of plants (fruit, blossom, foliage, stalks, tubers or roots) of the said crops and of related cultivated crops can be inhibited or destroyed with the active substances of the formula I, and also parts of plants subsequently growing remain preserved from such microorganisms. The active substances are effective against the phytopathogenic fungi belonging to the following classes: Ascomycetes and Basidiomycetes, and particularly against Phycomycetes, for example Phytophthora and Plasmopara. Furthermore, the compounds of the formula I have a systemic action. They can also be used as dressing agents for treating seed (fruits, tubers and grain), and plant cuttings to protect them from fungus infections, and also against phyto-pathogenic fungi occurring in the soil.
The invention hence relates also to the use of the compounds of the formula I for controlling phytopathogenic microorganisms, and/or for preventing infection on plants.

I 1 625~0 Compared with the cited compounds, the phosphonites of the formula I of the present invention have an improved micro~icidal spectrum for the protection of cultivàted plants, and are distinguished when applied in the customary amounts for protecting plants by the absence of phyto-toxicity, so that they protect the cultivated plants against harmful microorganisms, without damaging the plants.
For combating these microorganisms, the compounds of the formula I can be used on their own or together with suitable carriers and/or other additives. Suitable carriers and additives can be solld or liquid and they correspond to the substances common in formulation practice, such as natural or regenerated mineral substances, solvents, dispersing agents, wetting agents, adhesives, thickeners, binding agents and/or fertilisers. Active substances of the formula I can be used also in admixture, for example with pesticidal preparations or with preparations which improve the growth of plants.
The content of active substance in commercial compo-sitions is customarily between 0.01 and 90%.
Depending on physical parameters, such as aggregate state, solution concentratior., mode of production, and so forth, compounds of the formula I occur in the monomeric or oligomeric form, frequently in the dimeric form. Particu-larly metal salts tend to aggregate. Thus for example aluminium-tris(methylphosphonite) in D20 occurs in the following form CH3 CH (O)HP-O o/~ ~ o-p ~to)cH
CH3(0)HP~ O ~o~ / O-P~H(O)C~3 H~\ CH
The lH-NMR spectrum in D20 shows at a measuring frequency 1 1 625~0 of 60 MHz the following chemical shift ~ in ppm:

PCH3: d = 1-4 (d~ JPCH = 15 Hz~ 3H) PH : ~ = 7.0 (d~ JpH = 540 Hz, lH).

The decoupled 31P-NMR spectrum in D20 gives at a measuring frequency of 24.28 MHz two signals for P~H at - 22.88 ppm and for P H at - 26.5 ppm.
The dimeric form is clearly demonstrated by the 1:2 ratio of the signals Pa:P~.
The present invention relates to compounds of the formula I both in their monomeric form and in their oligomeric form. The formula I accordingly includes here and in the following both of these forms.
Temperature values in the following Examples are given in degrees Centigrade, and parts and percentages relate in all cases to weight.
Production Examples Example 1: Production of ~C 3 \OJ (1) Aluminium-tris(meth~lphosphonite) To 24.3 g of 0-ethyl-methylphosphonite in 200 ml of toluene are added, with stirring, 3.3 g of AlC13. There occurs an exothermic reaction with evolution of C2H5Cl, and a crystalline colourless product precipitates. The heterogeneous mixture is held at 110 for a further 3 hours and then cooled; diethyl ether is added and the mixture is subsequently filtered. The residue is repeatedly washed with diethyl ether, and residual solvent is removed in vacuo to thus yield 6.6 g (= 100% of theory) of aluminium-tris(methylphosphonite) as a colourless, crystalline, water-soluble substance.
Analysis: calculated: C 13.65% H 4.58% P 35.0 %
found : C 13.00% H5.00% P 33.50% .
Example 2: Production of ( ~ ) Al (5) Aluminium-tris(ethylphosphonite) A solution of 350 g (2.86 mols) of 0-ethyl-ethyl-phosphonite in 66 ml of nitrobenzene is added dropwise in the course of 2 hours at 100, with stirring, to a solution, prepared whilst being cooled, of 127.3 g (0.95 mol) of AlC13 in 480 ml of nitrobenzene~ with an intense evolution of ethyl chloride occurring. After the evolution of gas has finished, the reaction mixture is heated to 120, and a fresh evolution of gas can be observed. After a further 2 hours, the mixture is cooLed to room temperature, and 3 litres of acetone are added;
the mixture is subsequently vigorously stirred, and colourless crystalline aluminium-tris(ethylphosphonite) then precipitates. This is filtered off, repeatedly washed with diethyl ether, and dried in vacuo;
yield: 283 g (= 96.98% of theory);
analysis:
calculated: C 23.54% H 5.93% P30.36% Al 8.82%
found : C 23.70% H 6.20% P30.30% Al 8.85% .
Example 3: Production of

3 ~
~ -c - P J Al (11) Aluminium-t_is(tertiary butylphosphonite) 20 ml of dilute hydrochloric acid are added dropwise 7~

to 10 g (6Z.9 mmols) of tert-butyldichlorophosphine, and the solvent is removed in vacuo. The tert-butylphosphonic acid remaining as residue is neutralised with sodium hydroxide soLution, anda solution of 7.87 g (20.97 mmols) of Al(N03)3-9H20 in 15 ml of water is added. There is formed a white precipitate of aluminium-tris(tertiary-butylphosphonite), which is filtered off, washed and dried;
yield: 6 g (= 73.3% of theory);
analysis:
calculated: C 36.93% H 7.75V/o p 23.81% Al 6.91%
found : C 35.40% H 7.80% P 23.80% Al 6.83% .
Example 4: Production of CH3 ~\OC u (16) 0-Ethyl-methylphosphonite A solution of 280 ml of ethanol and 280 ml of triethyl-amine, dissolved in 400 ml of diethyl ether, is added dropwise, with stirring and ice-cooling, to 233.8 g (2 mols) of methyldichlorophosphine dissolved in 1200 ml of diethyl ether. The mixture is stirred for a further 10 hours, the ammonium salt is then filtered off, and the filtrate is distilled to thus obtain 168.5 g (= 78% of theory) of 0-ethyl-methylphosphonite as a clear colourless liquid, b.p. 71/20 Torr.
Example 5: Production of O~H
C2 5 \OC H (17 0-EthYl-ethylphosphonite There are obtained, in a manner analogous to that of ~ 1 6~7i~

Example 4, from 52.4 g of e~hyldichlorophosphine in 240 ml of diethyl ether with 44.2 g of ethanol and 40.5 g of triethylamine in 80 ml of diethyl ether, after fractional distillation, 47.4 g (= 97% of theory) of 0-ethyl-ethyl-phosphonite as a colourless liquid, b.p. 70-74/18 Torr.
Example 6: Production of 11~
C2~5-P\ ( 19 ) Ethylphosphonic acid 50 ml of water are added dropwise, with ice-cooling and with stirring, to 100 g (0.764 mol) of ethyl-dichlorophosphine in 500 ml of dioxane. The mixture is stirred at room temperature for a further 10 hours, and the solvent and excess water are subsequently removed under high vacuum; yield: 71.8 g (= 100% of theory): colourless oil with nD26 = 1.4498.
Example 7: Production of 2 i \~ Na~ (25) Sodium ethylphosphonite 3.8Z g (95.4 mmols) of sodium hydroxide in 20 ml of water are added dropwise, with stirring, to 8.9 g (95.4 mmols) of ethylphosphonic acid in 30 ml of water, and the reaction mixture is stirred at room temperature. After removal of the solvent under high vacuum, the yield is 11.0 g (= 100% of theory) of colourless crystals having a mel~ing point of ~ 300.

~ ~ 6257~

Example 8: Production of o C2~5 -\o~ N~ ~ (26) Ammonium-ethylphosehonite To 8 9 g (95.4 mmols) of ethylphosphonic acid in 30 ml of water is added dropwise at 20-30, with stirring, an equivalent amount of an aqueous ammonia solution. The reaction mixture is stirred at room temperature for a further 2 hours, and the solvent is subsequently removed under high vacuum; yield: 10.1 g of colourless crystals (= 95.3% of theory); m.p. 81-84.
Example 9: Production of 2 ; \Oe ~ 3-C1l~23 (28) Undecylammonium-ethYlphosphonite 20.5 ml (95.4 mmols) of undecylamine, dissolved in 20 ml of water, are added dropwise at 20-30, with stirring, to 8.9 g (95.4 mmols) of ethylphosphonic acid in 30 ml of water. The reaction mixture is stirred for a further 2 hours at room temperature, and the solvent is subsequently removed under high vacuum; yield: 21.1 g (= 83.4% of theory) of yellow oil.
Analysis: calculated: N 5.28% P 11.67%
found : N 5.27% P 11.53% .
Example 10: Production of 2 5 0 ~(C4Hg~)4 - (23 Tetr~butylammonium-ethylphosphonite 91.9 ml of aqueous tetrabutyLammonium hydroxide solution (40% = 95.4 mmols) are added dropwise at 20-30, with stirring, to 8.9 g (95.4 mmols) of ethylphosphonic acid in 30 ml of water. The reaction mixture is stirred at room temperature for a further 12 hours, and the solvent is subsequently removed under high vacuum to thus obtain 26.7 g (- 83% of theory) of a light-yellow oil.
Example 11: Production of ~ ~ ) (27) Nickel-bislethylphosphonite)

4.7 g (39.9 mmols) of nickel carbonate are added at room temperature, with stirring, to a solution of 7.5 g (79.7 mmols) of ethylphosphonic acid in 100 ml of water.
The reaction mixture is refluxed for 1 hour, in the course of which an evolution of C02 can be observed, and the water is subsequently removed in vacuo; yield: 9.7 g (= 100% of ~heory) of a green solid substance.
Example 12: Production of ~2~5- P\~) ~n ( Man~anese-bis(ethylphosphonite 4.6 g (39.9 mmols) of manganese carbonate are added portionwise at room temperature, with stirring, to a solution of 7.5 g (79.7 mmols) of ethylphosphonic acid in 100 ml of water. The reaction mixture is refluxed for l hour, and the water is subsequently removed iIl vacuo;

l l ~2570 yield: 7.9 g (= 82.3% of theory) of colourless crystals.
Example 13: Production of P\ ) zn ( 6) Zinc-bis(ethyLphosphonite) 7.3 g (39.3 mmols) of basic zinc carbonate are added portionwise at room temperature, with stirring, to a solution of 7.5 g (79.7 mmols) of ethylphosphonic acid in 100 ml of wa~er. After the evolution of C02 has finished, the reaction mixture is refluxed for 1 hour, and the water is subsequently removed in vacuo; yield:
4.9 g (49% of theory) of a white solid substance.
Example 14: Production of ~ ) (8) Copper-bis(ethylphosphonite) 2.3 g (18 . 6 mmols) of copper carbonate are added portionwise at room temperature, with stirring, to a `solution of 3.5 g (37.2 mmols) of ethylphosphonic acid in lao ml of water. After the evolution of C02 has subsided, the water is removed from the reaction mixture at 30-40 under hig~ vacuum; yield: 4.6 g (= 100% of theory) of a brown solid substance.

`1 J~6~-~7~

The following products of the formula I can be produced in an analogous manner:
. .
11~
Table 1 R-P\ (I) OX
.-- . .' Comp. R X Physical constants and elementary No. anaLysis: calculated in %
. found in %
: . - ., _ . I
1 CH V3. A~ C 13.65; H 4,;8; P 35,0 3 C 13,00;H ;,00; P 33,5 _ __ 2 c~3 L/2 Mn . _ _ 3 CH3 L/2 Fe 4 CH3 V2 Sn _ _ C2H L/3 Al C 23,54; H 5,93; P 30,36; Al 8,82 C 23,70; a 6,20; P 30,30; Al 8, as 6 C2H5 V2 Zn white solid substance .~
7 C2H~ V2 Mn white solid substance ~-8 C2H; V2 Cu brown solid substance _ _ _ , 9 C3H7-i 1~3 Al _ _ .
C3H7~n L/2 Mn _ _ . ~ _ 11 (CH ) C L/3 Al C 36,93; H t,75; P 23,81; Al 6,91 3 3 C 35,40; H 7,80; P 23,80; Al 6,83 l ~ 62570 . Comp. R ~ X Physical conStants and ele~en-No. tary analysis: calculated n ~ol _ _ . j 12 C4H9~n V3 Al ~ _ . _ _ 13 (C~3)3C Na _ ~ _ 14 3 L/2 Mg _ _ _ 16 CH3 C2d5 b p.71C~20 Torr 17 C H C H b.p.70-74C/18 ~orr _ ?`~ _ 2 5 _ 18 CH3 C4H9~n 19 C ~5 Hviscous oil ~ - 1.4498 CH3 NH(CH3)3~
__ 21 ~ 'N(C4H9~n)4 .

22 n~ ~U~ .
__ :;
23 2 9 N(C4H9-n)4 light-yellow oil 24 C3H7-i 2 3 _ C H Na m-p- ~300 2 ~
26 C2~5 NH4 m.p. 81-84 . 27C~H V2 Ni green solid substance ¦ ¦ 2 5 3 11 23 N 5 27 P 11 53 1 1 6257~

For application, the compounds of the formula I can be made up into the following preparations.
Formulation Examples E~ample 15: Solid preparations Dusts and scatterin~ a~ents contain in general up to 100% of active substance. A 5% dust can consist for example of 5 parts of the active substance and 95 parts of an additive such as talcum, or of 5 parts of the active substance, 4 parts of highly dispersed silicic acid and 91 parts of talcum. In addition to these, other mixtures with carriers and additives of this type and of other types customary in formulation practice are conceivable.
These dusts are produced by mixing and grinding the active substances with the carriers and additives, and they can be dusted on in this form.
Granulates, such as coated granules, impregnated granules and homogeneous granules, and also pellets, usually contain 1 to 80% of active substance. Thus, a

5% granulate can for example be composed of 5 parts of the active substance, 0.25 part of epoxidised vegetable oil, 0.25 part of cetyl polyglycol ether, 3.50 parts of poly-ethylene glycol and 91 parts of kaolin (preferred particle size 0.3 - 0.8 mm). The granulates can be produced as follows: The active substance is mixed with the epoxidised vegetable oil, and the mixture is dissolved in 6 parts of acetone; the polyethylene glycol and cetyl polyglycol ether are then added. The solution thus obtained is sprayed onto kaolin, and the acetone is subsequently evaporated off in vacuo. A microgranulate of this type is advantageously used for combating soil fungi.
Example 16: Liquid preparations There is generally made a distinction between active-substance concentrates which are dispersible or soluble 1 ~62S7 in water and aerosols. Water-dispersible concentrates of active substance include for example wettable powders and pastes, which usually contain in the commercial packing 25 - 90% of active substance, and in ready-for-use sol~tions 0.01 - 15~/o of active substance. Emulsion concentrates contain 10 to 50% of active substance, and solution concentrates contain in the ready-for-use solution 0.0001 to 20% of active substance. A 70% wettable powder can thus consist for example of 70 parts of active substance, 5 parts of sodium dibutylnaphthyl sulfonate, 3 parts of naphthalenesulfonic acid/phenoLsulfonic acid/formaldehyde condensate (in the mixture ratio of 3:2:1), 10 parts of kaolin and 12 parts of chalk (for example Champagne chalk).
A 40% wettable powder can consist for example of the following substances: 40 parts of active substance, 5 parts of sodium lignin sulfonate, 1 part of sodium dibutyl-naphthyl sulfonate and 54 parts of sillcic acid. A 25%
wettable powder can be prepared in various ways. It can thus be composed for example of: 25 parts of active substance, 4.5 parts of calcium lignin sulfonate, 1.9 parts of chalk (for example Champagne chalk)/hydroxyethyLene cellulose mixture 1:1, 1.5 parts of sodium dibutylnaphthyl sulfonate, 19.5 parts of silicic acid, 19.5 parts of chalk (for example Champagne chalk) and 28.1 parts of kaolin.
A 25% wettable powder may for example also consist of 25 parts of active substance, 2.5 parts of isooctylphenoxy-polyoxyethylene-ethanol, 1.7 parts of a (Champagne)chalk/
hydroxyethyl cellulose mixture 1:1, 8.3 parts of sodium silicate, 16.5 parts of kieselguhr and 46 parts of kaolin.
10% wettable powder can be produced for example from 10 parts of active substance, 3 parts of a mixture of sodium salts of saturated fatty alcohol sulfonates, 5 parts of a naphthalenesulfonic acid/formaldehyde condensate and 82 parts of kaolin. Other wettable powders can be mixtures 1 3 ~2~70 of 5 to 30% of active substance together with 5 parts of an absorptive carrier material such as silicic acid, 55 ~o 80 parts of a carrier such as kaolin and of a dispersing agent mixture consisting of 5 parts of sodium aryl sulfonate and 5 parts of an alkylarylpolyglycol ether.
A 25% emulsion concentrate can contain for example the following emulsifiable substances: 25 parts of active substance, 2.5 parts of epoxidised vegetable oil, 10 parts of an alkylaryl sulfonate/fatty alcohol polyglycol ether mi~ture, 5 parts of dimethylformamide and 57.5 parts of xylene.
Emulsions of the required application concentration can be produced from concentrates of the described types by dilution with water, and these emulsions are particularly suitable for leaf application. In addition, other wettable powders having different mixture ratios or containing other carriers and additives common in formulation practice can be produced. The active substances are intimately mixed in suitable mixers with the additives mentioned, and the mixture is subsequently ground in the appropriate mills and rollers. There are obtained wettable powders which have e~cellent wetting and suspension properties, which can be diluted with water to give suspensions of the desired concentration, and which can be used in particular for leaf application Compositions of this type also form subject matter of the present invention.
Compositions formulated in the manner described above and containing as active ingredient a compound of the formula I (for example compound No. 1, 5-8, 11, 16, 17, 19, 23, 25, 26 or 27) can be used with a very high degree of success for combating phytopathogenic fungi. Also other compounds from Table 1 can be used with equal or similar success.

~ ~ B~57~

Biolo~ical Examples The spray liquors employed in the following Examples were formulated in the manner described in the foregoing.
Example 17 Action_ gainst Plasmopara viticola on ~rape vines a) Residual-Protective action Grape-vine cuttings in the 4-5-leaf stage were sprayed with a spray liquor prepared from wettable powder of the active substance (o.06% of active substance). After 24 hours, the treated plants were infested with a suspension of sporangia of the fungus. The extent of fungus infection was assessed after incubation during 6 days at 20 with 95-100% relative humidity.
b) ~esidual-curative action Grape-vine cuttings in the 4-5-leaf stage were infested with a suspension of sporangia of the fungus. ~fter an incubation for 24 hours in a moist chamber at 20 with 95-100% relative humidity, the infested plants were dried and then sprayed with a spray liquor prepared ~rom wettable powder o~ the active substance (o.06% of active substance).
The sprayed-on coating was dried and the treated plants were returned to the moist chamber. An assessment of fungus infection was made 6 days after infestation.
Compounds of the formula I exhibited against Plasmopara viticola on grape-vines a very good fungicidal action.
Compared with the fungus infection present on the control plants (100% infection), the infection on plants treated with compounds from Table 1 was reduced to less than 20%.
The active substances Nos. 1, 5, 7, 8, 11, 16, 23 and 26 prevented fungus infection almost completely (0 to 5V/o infection).

l l ~2570 Example 18 Action a~ainst Phytophthora infestans on t ato plants a) Residual-Pro~ective action Tomato plants were sprayed, after 3-weeks' cultivation, with a spray liquor produced from wettable powder of the actlve substance (0.06~o of active substance). After 24 hours, the treated plants were infested with a suspension of sporangia of the fungus. An assessment of the fungus infection was made after incubation of the infested plants during 5 days at 20 with 90-100 relative humidity.
b) Residual curative action After a cultivation period of three weeks, to~nato plants were infested with a suspension of sporangia of the fungus.
After an incubation time of 22 hours in a moist chamber at 20 with 90-100% relative humidity, the infested plants were dried, and subsequently sprayed with a spray liquor prepared from wettable powder of the active substance (o.06%
of active substance). After drying of the applied coating, the treated plants were returned to the moist chamber. An assessment of fungus infection was made 5 days after infestation.
c) SYstemic action A spray liquor prepared from wettable powder of the active substance (o.o6% of active substance, relative to the volume of soil) was applied to the soil in which tomato plants had been cultivated for 3 weeks. Care was taken to ensure that the spray liquor did not come into contact with the parts of the plants above the soil. After 48 hours, the treated plants were infested with a suspension of sporangia of the fungus. An assessment of fungus infection was made after incubation of the infested plants during 5 days at 20 with 90-100% relative humidity.

Compounds of the formula I exhibited against Phyto-phthora infestans on tomato plants a very good fungicidal ac~ion. Compared with the fungus infection present on the untreated but infested control plants (infection = 100%), the infection on plants treated with compounds from Table 1 was reduced to less than 25%. The active substances Nos. 1, 5 and 11 reduced infection even down to 0 to 10%.

Claims

Claims:

1. A process of combating phytopathogenic fungi or preventing plants from their attack, which process comprises applying to the plants or to the locus to be protected an effective amount of an alkylphosphonite of the formula I
RPH(O)OX (I) wherein R is C1-C4-alkyl, and x is hydrogen, C1-C4-alkyl or an ammonium ion, a hydrazinium ion or a metal ion of the first to fourth main group or of the first to eighth subgroup.

2. A process according to claim 1, which comprises applying an effective amount of a metal salt of the formula I as claimed in claim 1.

3. A process according to claim 1, which comprises applying an effective amount of an ammonium or hydrazinium salt of the formula I as claimed in claim 1.

4. A process according to claim 3, which comprises applying an effective amount of a lower alkylammonium salt of the formula I as claimed in claim 1.

5. A process according to claim 1, which comprises applying an effective amount of at least one of the following compounds:
Aluminium-tris(methylphosphonite), Aluminium-tris(ethylphosphonite), Manganese-bis(ethylphosphonite) and Copper-bis(ethylphosphonite).

6. An alkylphosphonite of the formula Ia R'PH(O)OX' (Ia) wherein R' is C1-C4-alkyl, and X' is an ammonium ion, a hydrazinium ion, or a metal ion of the third or fourth main group or of the first to eighth subgroup.

7. A metal salt of the formula Ia according to claim 6.

8. An ammonium salt and hydrazinium salt of the formula Ia according to claim 6.

9. An aluminium salt of the formula Ia according to claim 7.

10. An manganese salt of the formula Ia according to claim 7.

11. A copper salt of the formula Ia according to claim 6.

12. Aluminium-tris(methylphosphonite) according to claim 9.

13. Aluminium-tris(ethylphosphonite) according to claim 9.

14. Manganese-bis(ethylphosphonite) according to claim 10.

15. Copper-bis(ethylphosphonite) according to claim 11.

16. A process for producing an alkylphosphone derivative of the formula Ia according to claim 6, which process comprises in the case of the ammonium and hydrazinium salts:

a) reaction of an alkylphosphonic acid of the formula R'PH(O)OH, wherein R' is C1-C4-alkyl, with an equivalent amount of an amine or of a hydrazine; or b) reaction of an alkyl ester of an alkylphosphonic acid of the formula R'PH(O)OH, wherein R' is C1-C4-alkyl, with an ammonium or hydrazinium halide, with splitting-off of the corresponding alkyl halide; or c) reaction of an alkylphosphonic acid alkyl ester of the formula I with a tertiary amine to effect quaternisation; or in the case of the metal salts of the subgroup elements and of the main group elements of the third and fourth main group:

d) reaction of an alkylphosphonic acid alkyl ester of the formula I with a metal halide, or reaction of an alkali metal salt of the formula I with a sulfate, nitrate or halide of the main group or subgroup element.

17. A process according to claim 16, wherein there is produced a compound of the following formulae:
Aluminium-tris(methylphosphonite), Aluminium-tris(ethylphosphonite), Manganese-bis(ethylphosphonite and Copper-bis(ethylphosphonite).