GB1561422A - Ester of 1 - phenyl - 2-nitro - 1,o - propanediol and their plant protecting and fungicidal compositions - Google Patents

Abstract

The crop protection product contains, as active substance, one or more nitroalkanol derivatives of the formula I. R has the meaning given in patent claim 1. The crop protection product is obtained by preparing the compound of the formula I by acylating 1-phenyl-2-nitro-1,3-propanediol and mixing the active substance with a formulation auxiliary. The acylation is carried out under mild conditions. <IMAGE>

Description

(54) ESTERS OF l-PHENYL-2-NITRO-1,3-PROPANEDIOL AND THEIR PLANT PROTECTING AND FUNGICIDAL COMPOSITIONS (71) We, EGYT GYOGYSZERVEGYESZETI GYAR, a Hungarian Body Corporate of 30, Kereszturi ut, Budapest X, Hungary, do hereby declare this invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to novel plant protecting compounds and compositions and to their preparation and use. The active components of the plant protecting compositions according to the invention are, with the exception of one derivative, believed to be novel per se. In accordance with the invention even the known derivative is prepared by a new procedure.

Threo-l-phenyl-2-nitro-l,3-propanediol diacetate, the only known member of the active compounds of general formula (I) below, is an intermediate produced in the synthesis of chloramphenical. According to the known method this compound is prepared by reacting cinnamic acetate with sodium nitrite and treating the resulting DL-erythro- I -phenyl-nitroso-2-nitro-3-acetoxy-propane with acetic anhydride in sulfuric acid [Chem. Abstr. 50. 6360(1956)]. No biological activity was attributed to this compound. Owing to the stereo-chemistry of the reactants used the known process enables one to prepare the threo isomer only.

The novel plant protecting composition according to the invention contains an effective amount of one or more nitroalkanol derivative(s) of the general formula (I)

wherein R is a C,~20 alkyl group or a phenyl or phenyl-C,~3 alkylene group having optionally one or more C13 alkyl or halogen substituent(s) on the phenyl ring, together with an adjuvant, diluent or carrier, said composition not being a simple solution of threo-l-phenyl-2-nitro-l,3-propanediol diacetate in an organic solvent free from adjuvants.

The compounds of the general formula (I) have two centres of asymmetry (the carbon atoms in positions I and 2); consequently they exist in the form of two diastereomeric pairs (racemic erythro and threo compounds), which can be resolved further to yield the respective optically active laevorotatory and dextrorotatory compounds. Thus the total number of isomers amounts to four. Of the compounds having the general formula (I) the threo isomer of the R=methyl derivative is known.

The plant protecting compositions according to the invention may contain one or more compound(s) of the general formula (I) as active principle, optionally in admixture with certain other known plant protecting substances. The total active agent content of the plant protecting compositions amounts e.g. to 0.01 to 96 ".

Beside the active agents, the compositions contain usual additives, such as solvents, carriers, diluents, extenders, dispersing agents, surfactants, agents modifying the duration of the desired effect, stickers and/or stabilizers, all of which agents are included in the terms "adjuvant, diluent or carrier", in an amount necessary to make up the final weight (100%) of the composition.

The active compounds of the general formula (I) may be formulated into usual agricultural compositions. such as solutions, emulsions, suspensions, powders, dispersible powders, sprays, spray powders, wettable powders, foams, pulps, granulates, microgranulates, aerosols, emulsifiable concentrates, suspension concentrates preferably in colloidal form and, compositions for seed dressing. Of these compositions the wettable powders (WP), emulsifiable concentrates (EC), colloidal suspension concentrates (Col.), microgranulates and sprays are particularly preferred.

The compositions are prepared according to methods known per se, such as by admixing the active compounds with carriers (e.g. liquid solvents, liquified gases and/or solid carriers) optionally in the presence of surfactants (e.g. emulsifying agents and/or dispersing agents) and/or foaming agents. If water is used as solvent, organic liquids can also be admixed with the composition as co-solvents.

Solvents or liquid carriers include e.g. the following substances: aromatic compounds, such as xylene, toluene or alkylnaphthalene, chlorinated aromatic compounds, such as chlorobenzene, chlorinated aliphatic hydrocarbons, such as methylene chloride or ethylene chloride, aliphatic hydrocarbons, such as paraffin hydrocarbons, alicyclic hydrocarbons, such as cyclohexane, alcohols, such as butyl alcohol or glycol, ethers and esters of said alcohols, ketones, such as acetone, methyl-ethyl-ketone or cyclohexanone, polar organic solvents, such as dimethyl formamide or dimethyl sulfoxide, and water.

As liquified gases e.g. liquified propellants for aerosol compositions, such as halogenated hydrocarbons, or liquified butane, propane, or pressurised nitrogen and carbon dioxide can be applied. Of the solid carriers the following substances are illustrative: natural rock flours, such as kaolin, clay minerals, talc, chalk, quartz, montmorillonite or diatomaceous earth, and synthetic rock flours, such as highly disperse silicic acid, aluminium oxide and silicates. In the preparation of granular compositions the following solid carriers are preferred: crushed and fractionated natural rocks, such as calcite, marble, pumice stone, sepiolite and dolomite, and flours of organic origin, such as ground tobacco stalk or ground coconut shell. As emulsifying and/or foaming agents, non-ionic and anionic substances, such as polyoxyethylene-fatty acid esters, polyoxyethylene-fatty alcohol ethers (e.g. alkyl-aryl-polyglycol ethers), alkylsulfates, alkylsulfonates, arylsulfonates and hydrolyzed proteins can be used. Dispersing agents include e.g. lignin, sulfite waste liquors and methyl cellulose.

The compositions may also contain stickers (adhesive agents), such as carboxymethyl cellulose or powdery, granular or latex-like polymers of natural or synthetic origin (e.g. gum arabic, polyvinyl alcohol or polyvinyl acetate).

If desired, dyestuffs, such as inorganic pigments, and trace elements, such as salts of boron, iron, copper, cobalt, manganese, molybdenum and zinc, can also be admixed with the active agents.

The compositions according to the invention can be applied to the area to be treated either as such or after diluting them to the appropriate final concentration.

In order to facilitate handling, transporting and storage it is preferred to prepare the compositions in the form of concentrates which can be diluted to the required final concentration directly before application.

The active agent contents of the compositions ready for use may vary within wide limits. These compositions may contain for instance 0.000001 to 960,6 by weight, preferably 0.01 to 10% by weight, of active agent. The compositions are applied to the area to be treated according to known techniques, such as spraying or watering.

The active agents of the general formula (I) are prepared according to the invention by reacting l-phenyl-2-nitro-l,3-propanediol of the formula (II)

or an alkali metal salt thereof with an appropriate acylating agent under mild conditions which do not substantially decompose the compounds of general formulae (I) and (II) This method is theoretically simple: in practice, however, several difficulties have been observed when substances structurally similar to that of the formula (II) compound are to be acylated. These difficulties can be atributed partly to the aldol character of the compound and partly to the presence of a nitro group. Among others, the presence of a nitro group precludes the applicability of basic acid binding agents in the acylation procedure, since otherwise the nitro group undergoes a tautomeric rearrangement and the epimeric nitronic acid derivative forms. Furthermore, basic agents set up an aldol equilibrium in the reaction mixture, the "retroaldol" component of which leads to the dissociation of the molecule. Moreover, I-phenyl- 2-nitro-1,3-propanediol is, like other nitro alcohols, a compound so labile that no base is required to split off the acidic proton attached to the carbon atom in position 2. In other words, the basicity of the solvent (such as aqueous alcohol) is sufficient to initiate the decomposition process. In solutions of l-phenyl-2-nitro1,3-propanediol a considerable degree of decomposition can be detected even upon standing at room temperature for some hours; and the rate of decomposition increases abruptly upon raising the temperature. When examining the formation and decomposition processes of l-phenyl-2-nitro-ethane-l-ol, a compound structurally very similar to l-phenyl-2-nitro-l,3-propanediol, it has been stated that this compound cannot be acylated at all [Gazz, Chim. Ital. 79, 192-201(1949)]. This fact can be fully explained by the factors discussed above.

Based on the above one could not conclude that l-phenyl-2-nitro-l,3- propanediol could be acylated at all, and no such procedure has been described so far in the literature.

Now it has been found, unexpectedly, that the acylated nitro compounds, of the general formula (I) can be prepared from the formula (II) compound quite easily and without the occurrence of side reactions when either of the isomeric forms (erythro or threo) or an isomeric mixture of l-phenyl-2-nitro-1,3-propanediol or an alkali metal salt thereof is reacted with an acylating agent under mild conditions. As acylating agent preferably an acyl halide or an acid anhydride is applied. The reaction can be performed either in the presence or in the absence of solvent media. When an alkali metal salt (preferably the sodium salt) of l-phenyl-2 nitro-l,3-propanediol is used as starting substance, it is particularly preferred to perform the reaction with an acyl halide in a solvent, such as in acetic acid, at a temperature about 40"C. The reaction requires about 8 hours. In this way a mixture of erythro and threo isomers, containing the two isomeric forms in a ratio of about 1:1, is obtained with a good yield. The isomeric mixture can be separated into the pure isomers by crystallization.

It is also preferable to start with the pure erythro or threo isomer of 1-phenyl2-nitro-1,3-propanediol and to perform the reaction without adding any further solvent to the mixture. In this instance the corresponding pure erythro or threo isomer of the acylated compound is obtained with good yields.

According to a further preferred method an acid anhydride is used as acylating agent, and the reaction is performed without a solvent, in the presence of a catalytic amount of a mineral acid or the acid chloride corresponding to the acid anhydride. Of course, the reaction can also be performed with a mixture of the appropriate acyl halide and acid anhydride.

The formula (II) compound used as starting substance in the process ot the invention is an easily available, known substance. The sodium salt can be prepared in a known manner [J. Am. Chem. Soc. 2465 (1949)1. When the pure erythro or threo isomer is required as starting substance, it can be prepared preferably from the sodium salt of the isomeric mixture (German patent specification No.

1,064,937), or the pure isomers can be prepared directly in a single step by reacting benzaldehyde with nitroethanol in the presence of an alkali metal hydroxide catalyst. This latter method is the most preferred one to obtain the pure isomers of the formula (II) compound.

The compounds of the general formula (I) and mixtures thereof possess strong fungicidal and acaricidal activities without exerting, (in our tests), any harmful phytotoxic effect at useful rates of application. For certain insects a considerable antifeeding effect can also be observed: thus, for example, winged migratory locusts do not consume plants sprayed with the compositions according to the invention. The compositions according to the invention also possess considerable aphicidal effects. Therefore one aspect of the invention provides a method for the control of fungal, acarid and/or insect pests in a plant locus which comprises applying to said locus an effective amount of compound of general formula (I).

Furthermore, the compounds of general formula (I) accelerate the germination of certain cultivated plants and also stimulate the growth rate as measured by the increase in the dry weight. The compositions according to the invention, when applied to susceptible plants prior to emergence in the dosages tested, stimulated the dry weight increase of the plants and increased their germination abilities; on the other hand, when applied after emergence. they did not show any negative phototoxic effect. Thus a further aspect of our invention is a method for stimulating the germination and growth of plants which comprises applying to the locus of said plants an effective amount of a compound of general formula (I).

Based on the test results the compositions according to the invention are thought to be active against the following fungus strains: Alternaria tenuis, Fusarium graminearum, Trichotecium roseum, Aspergillus flavus. Penicillium species, Rhizopus nigricans. Phvtophtora infestans, Monilia fructigena, Cladosporium herbarium, Fusarium oxysporum. Aspergillus oryzae, Mucor mucedo, Botrvthis cinerea and endostigme pirina.

The biological effect of the compositions according to the invention were tested primarily on the following plant types: what, maize. sorghum, mustard, sunflower, potato, pea and other cultivated plants.

The tests were performed as follows: Soil samples were layered into culture trays, and an appropriate number of seeds (in the testing of wheat, maize, sorghum, sunflower, mustard and pea, 100 seeds per tray) was sown into the soil. The active agent was applied to the soil either prior to or after plant emergence. The active agents of the general formula (I) wave applied in a dosage corresponding to 6 kg/acre. Some of the trays were not treated; these served as controls. Optimum conditions were provided for germination, and the percentage germination, the heights of the 14 days old seedlings, furthermore their green and dry weights were determined.

In a test series the plants were treated prior to plant emergence with a threoerythro mixture of 1-phenyl-2-nitro-1,3-propanediol diacetate ground to a particle size of I to 20y (a composition prepared according to Example 14). In two further test series the treatments were performed after plant emergence with a composition prepared according to Example 15 or 16, containing a threo-erythro mixture of l-phenyl-2-nitro-1,3-propanediol diacetate as active principle. The results are listed in Table 1.

Table 1 Green Treatment Plant Germination, o/x Height, oox weight, or pre-emergent wheat 63 105.5 105 maize 108 99 107 sorghum 111 110 120 mustard 116 104 121 sunflower 108 98 120 pea 100 118 131 post-emergent wheat - 130 maize 125 flax - 130 capsicum - - 130 tomato - - 120 XControl=100% Erythro- 1 -phenyl-2-nitro- 1 3-propanediol diacetate, a compound prepared as described in Examples 1, 6 and 7, was dissolved in acetate, and the solution was diluted with water to a final concentration of 0.1 to 1%. The activities of solutions with varying concentrations were tested against the fungus strains listed in Table 2 by the disc method. The diameters of the colonies developed were measured, and the degree of inhibition was determined in comparison with the values measured for the untreated controls. The degree of inhibition was characterized by a. numerical scale ranging from 1 to 4, wherein the individual figures had the following meanings: 1: total inhibition, 2: partial covering, 3: total covering but certain other biological effects (such as morphological changes) can be detected in relation to the controls, 4: no change in relation to the controls.

The results are summarized in Table 2.

Table 2 Ervthro diacetate Dithianon Captatol Fungus strain 0.1% 0.3% 0.5 1% 0.1 0.1% Control Botrytis 1 1 1 1 3 1 4 cinerea Cladosporium 1 1 1 1 3 - 4 herbarum Fusarium 2 1 1 1 4 1 4 oxysporum Penicillium 2 1 1 1 3 - 4 species Aspergillus 2 1 1 1 3 - 4 oryzae Alternaria 2 2 1 1 - 1 4 tenuis Dithianon: 2,3-dicyano-1,4-dithia-anthraquinone Captatol: N-( l,1,2,2-tetrachloroethylthio)-4-cyclohexene- 1,2 dicarboximide The results of some additional tests are summarized in Tables 3 to 7.

Table 3 Concentration of the spray Test Compound (formulation) solution, % organism Mortality % A compound of Ex. 0.02 Tetranychus 4.6 1, 6 and 7 (wettable 0.2 urticae 76.0 powder with 50% 2.0 100.0 active agent content) Compounds of Ex. 3 to 6 0.02 ,, 13.5 (wettable powder with 0.2 88.8 50% active agent content) 2.0 97.3 Diazinon, Phenkapton 0.2 ,, 100.0 Compounds of Ex. 1 to 8 2.0 Megaurea 88.0 2.0 vicae 70.0 Dimethoate 2.0 " 100.0 - - - - - - - - - - - - - - - - - - - - Compound of Ex. 9 0.01 Acyrthosiphon 35* (powder, 1 to 20,u) 0.1 (leaf aphid) 95* 1.0 100* 0.01 0.1 100** 1.0 100** Methyl parathion 0.5 ,, 100* 0.5 *after 24 hours **after 48 hours Diazinon: 0,0-diethyl-0-2-isopropyl-4-methyl-6-pyrimidyl thiophosphate Phenakapton: S-(2,5-dichlorophenylthiomethyl)-0,0-diethyl-di thiophosphate Dimethoate: dimethyl S-(N-methyl-carbamoylmethyl)-dithio phosphate Methyl parathion: 0,0-dimethyl-0-(p-nitrophenyl)-thiophosphate Table 4 Concentration of the spray Test Anti-feeding Compound (formulation) solution, % organism effect Compounds of Ex. I to 8 0. I Indian wmged Did not touch (wettable powder with 50% locusts the plant active agent content) 0.3 None (control) 0.0 ,, Consumed the Dlant Table 5 Compound Inhibition of (formulation) Conc. Test organism spore germination 0.1% 1.0% Compound of 0.1% Alternariatenuis partial total Ex. 2 (wettable 1.0% powder with 50% Fusarium graminearum partial total active agent Trichotecium roseum partial total content Aspergillus flavus partial total Penicillium species partial total Rhizopus nigricans partial total Botrytis cinerea none partial Phytophtora infestans partial total Endostigme pirina partial total Monilia fructigena none total Conc.=concentration of the spray solution, % Table 6 Test organism Compound (formulation) Conc. (substrate) Infection % Compound of Ex. i 0.05 Phytophtora infes- 5.0 (wettable powder 0.1 tans (potato leaves) 0.0 containing 50% of 1.0 0.0 active agent) Zineb (wettable powder containing 0.3 " 20.0 80 Sn of active agent) Untreated control 0.0 ,, 100.0 Compound of Ex. 2 Phytophthora infes (wettable powder 0.1 tans (potato slices)* 0.0 containing 50% of active agent) Compound of Ex. 2 0.01 Fusarium (potato 26 (wettable powder 0.1 leaves) 0 containing 50% of 1.0 0 active agent) Zineb (wettable powder containing 0.1 ,, 40 80% of active agent) Untreated control 0.0 " 50 Compound of Ex. 9 0.1 Phytophthora infes- 0 (wettable powder tans (potato leaves) containing 50% of active agent) Captan 0.2 ,, 0 Untreated control 0.0 " 60 Compound of Ex. 9 0.1 Phytophthora infes tans (potato slices)* 0 *infected under experimental conditions Conc.=concentration of the spray solution, % Zineb: zinc-ethylenebis(thiocarbamate) Captan: N-(trichloromethylthio)-4-cyclohexene-1,2-di carboximide Table 7 Concentration of the Inhibition of Activity*% Compound (formulation) spray solution, % Test organism spore germination 0.1% 1.0% 0.1% 1.0% Compound of Ex. 9 0.1% and 1.0% Alternaria tenuis total total 111 333 (wettable powder 0.1% and 1.0% Fusarium graminearum total total 300 833 containing 50% of 0.1% and 1.0% Trichotecium roseum total total 90 300 active agent) 0.1% and 1.0% Aspergillus flavus total total 150 466 0.1% and 1.0% Penicillium species total total 112 275 0.1% and 1.0% Botrytis cinerea total total 166 316 0.1% and 1.0% Rhizopus nigricans partial total 0 170 0.1 and 1.0% Mucor mucedo partial total 0 266 * The activity of 0.2% solution of Zineb (wettable powder containing 80% of active agent) was regarded as 100% The invention is described in detail by the aid of the following non-limiting Examples.

Example 1 Preparation of Erythro-1-phenyl-2-nitro-1,3-propanediol Diacetate 158 g of 1-phenyl-2-nitro-1,3-propanediol sodium salt are introduced within 25 minutes into 700 ml of stirred glacial acetic acid at a temperature not exceeding 20"C. Thereafter 304 ml of acetyl chloride are added to the mixture within 35 minutes at a temperature below 20"C. The reaction mixture is stirred for 14 hours at 40"C, and the separated sodium chloride is filtered off. The filtrate is diluted with 600 ml of petroleum ether and stirred for 2 hours under cooling with ice water.

The separated crystalline substance is filtered off. 55 g (25.6%) of erythro-l-phenyl 2-nitro-1,3-propanediol diacetate are obtained; m.p.: 81-820C.

The mother liquor is evaporated. 110.2 g (51%) of l-phenyl-2-nitro-1 .3- propanediol diacetate are obtained in the form of a threo-erythro isomeric mixture; m.p.: 55-610C.

The obtained compounds can be applied for plant protection purposes either separately or in admixture with each other.

Example 2 Preparation of Threo-1-phenyl-2-nitro-1,3-propanediol Diacetate 10 g of threo-1-phenyl-2-nitro-1,3-propanediol are added slowly into 16 ml of acetyl chloride at room temperature. Warming and a vigorous evolution of hydrochloric acid takes place. The cooling of the mixture is controlled so that its temperature does not exceed 40"C. When the evolution of hydrochloric acid subsides the mixture is stirred at 400C for additional 3 hours, thereafter it is allowed to stand at room temperature overnight.

The reaction mixture is diluted with a great amount of petroleum ether and cooled to 0 C. The separated crystalline substance is filtered off and washed with petroleum ether until the wash does not give acidic reaction. In this way 10.4 g (73%) of threo-l-phenyl-2-nitro-l,3-propanediol diacetate are obtained; m.p.: 72 .

Example 3 Preparation of Threo-1-phenyl-2-nitro-1,3-propanediol Diacetate 10 g of threo-l-phenyl-2-nitro-l,3-propanediol are dissolved in 30 ml of glacial acetic acid and 16 ml of acetyl chloride are added to the solution at room temperature. The reaction mixture is maintained at 400C for 3 hours, thereafter it is allowed to stand at room temperature overnight. The product is precipitated with a great amount of petroleum ether under cooling (0 C), and the mixture is allowed to stand in a refrigerator for some hours. 11.5 g (80.5%) of threo-1-phenyl-2-nitro-l,3- propanediol diacetate are obtained; m.p.: 70--720C.

Example 4 Preparation of Threo- 1 -phenyl-2-nitro- 1 ,3-propanediol Diacetate 35 g of threo-1-phenyl-2-nitro-l,3-propanediol are dissolved in 49 ml of acetic anhydride, and 49 ml of acetyl chloride are added to the solution at such a rate that the temperature of the mixture does not exceed 40 C. The mixture is maintained at 40 C for 8 hours, thereafter it is allowed to stand overnight. The mixture is poured into 200 g of crushed ice under stirring. A thick oil separates which crystallizes within a short time. The mixture is maintaining at 0 C for 2 hours, thereafter the crystals are filtered off and washed acid-free with cold distilled water. In this way 49.05 g (97.5 /n) of threo-l-phenyl-2-nitro-1,3-propanediol diacetate are obtained; m.p.: 71--72"C.

24.0 g of the above product are dissolved in 72 ml of isopropanol at a temperature of about 85 to 900 C, and the solution is allowed to stand at room temperature. The crystalline product separates within some hours. The crystals are filtered off and washed with cold petroleum ether. 22.19 g (92%) of purified threo1-phenyl-2-nitro-1,3-propanediol diacetate are obtained; m.p.: 72-73 C.

Example 5 Preparation of Threo-1-phenyl-2-nitro-1,3-propanediol Diacetate 19.7 g of threo-1-phenyl-2-nitro-1,3-propanediol are dissolved in 30 ml of acetic anhydride, and 0.2 ml of boron trifluoride etherate are added to the solution in such a way that its temperature does not exceed 20"C. The mixture is stirred at 40 C for one hour and then it is poured onto ice. The separated crystals are filtered off and washed with ice-cold distilled water. 26.2 g (93.20,) of threo-1-phenyl-2- nitro-l,3-propanedioldiacetate are obtained; m.p.: 69--710C.

21.0 g of the above compound are recrystallized from 50 ml of ethanol. 16.8 g (80.0 ,') of the purified substance are obtained: m.p.: 70.5--720C.

Example 6 Preparation of Erythro-1-phenyl-2-nitro-1,3-propanediol Diacetate 4.9 g of erythro-l-phenyl-2-nitro-l,3-propanediol are dissolved in 14.7 ml of glacial acetic acid, and 7.85 ml of acetyl chloride are added to the solution at room temperature. The mixture is maintained at 40 C for 6 hours, thereafter it is allowed to stand at room temperature overnight. A great amount of petroleum ether is added to the solution, and the mixture is kept in a refrigerator for 4 hours. The separated crystals are filtered off and washed with petroleum ether. 3.08 g (44%) of erythro-1-phenyl-2-nitro-1,3-propanediol diacetate are obtained; m.p.: 81 C.

Example 7 Preparation of Erythro-1-phenyl-2-nitro-1,3-propanediol Diacetate 8.0 g of erythro-1-phenyl-2-nitro-1,3-propanediol are dissolved in 11.2 ml of acetic anhydride, and 11.2 ml of acetyl chloride are added dropwise to the solution at a temperature not exceeding 400 C. The mixture is maintained at 40 C for additional 8 hours, thereafter it is poured onto 30 g of crushed ice with stirring. The product separates slowly. The mixture is maintained at 0 C for 2 hours, thereafter the product is filtered off and washed acid-free with cold (0 C) distilled water. The resulting 11.75 g of crude erythro-l-phenyl-2-nitro-l,3-propanediol diacetate are recrystallized from 66 ml of ethanol. The crystals are filtered off and washed with petroleum ether. 4.7 g (41%) of pure erythro-1-phenyl-2-nitro-1,3-propanediol are obtained; m.p.: 79--800C.

Example 8 Preparation of Threo-l-phenyl-2-nitro-1,3-propanediol Dipropionate 19.7 g of threo-1-phenyl-2-nitro-l,3-propanediol are added slowly into 40 ml of propionic anhydride containing 0.2 ml of boron trifluoride etherate. The mixture is stirred at 40 C for 2 hours and then it is poured onto crushed ice. The separated crystals are filtered off and washed with ice-cold distilled water. 28.6 g (92.6%) of crude threo-1-phenyl-2-nitro-1,3-propanediol dipropionate are obtained. After recrystallization from ethanol 25.25 g (88.5 /") of pure substance are obtained; m.p..

48--50"C.

Example 9 Preparation of Threo-l-phenyl-2-nitro-l,3-propanediol Dibenzoate 19.7 g of threo-1-phenyl-2-nitro-1,3-propanediol are added slowly into 28 g (24.1 ml) of benzoyl chloride at such a rate that the temperature of the mixture does not exceed 20 C. Thereafter the mixture is warmed to 85 to 900C and maintained at this temperature for 7 to 8 hours. The mixture is allowed to stand at room temperature overnight and then it is diluted with ether. The separated product is filtered off and washed acid-free with petroleum ether. 19.6 g (48.5%) of crude threo- 1 -phenyl-2-nitro- 1 3-propanediol dibenzoate are obtained. After recrystallization from a mixture of ethanol and tetrahydrofuran 15.8 g (80.5%) of pure substance are recovered: m.p.: 130.5-132 C.

Example 10 Preparation of Threo to stand overnight. The separated thick, oily product is isolated from the aqueous phase and dissolved in 15 ml of diethyi ether. The etheral solution is dried over magnesium sulfate and filtered. The filtrate is diluted with 25 ml of petroleum ether and the mixture is allowed to stand for some days. The separated crystalline crude product (5.6 g) is filtered off, triturated with 15 ml of ethanol, and the mixture is allowed to stand in a refrigerator overnight. The crystals are filtered off and washed with cold ethanol, The resulting crude product is recrystallized from 12.5 ml of ethanol. The crystals are filtered off and washed with cold ethanol and petroleum ether. 4.1 g (46.6 /") of threo-l-phenyl-2-nitro-1,3-propanediol bis(phenylacetate) are obtained; m.p.: 63-640C.

Example 12 Preparation of Threo- 1 -phenyl-2-nitro- 1 ,3-propanediol Bis(p-chlorobenzoate) A mixture of 1.95 g of threo-1-phenyl-2-nitro-l,3-propanediol and 5.35 g of pchlorobenzoyl chloride is stirred at 85 to 900C for 14 hours. The mixture is allowed to cool, admixed with ice, and allowed to stand overnight. The separated product is filtered off, washed with water and petroleum ether, and crystallized from 62 ml of ethanol. 1.08 g (23.4) of threo- 1 -phenyl-2-nitro- I ,3-propan ediol bis(pchlorobenzoate) are obtained; m.p.: 107-1 090C.

Example 13 Preparation of a wettable powder The formula (I) active agent is powdered in a micronizer until at least 800,, of the substance has the particle size of 1 to 20jut. The powder is homogenized with I to 5% by weight of a neutral or non-basic wetting agent and 20 to 60% by weight of a solid inert binding agent (such as kaolin or bentonite). The resulting wettable powder contains about 60 to 82% by weight of active agent.

Example 14 Preparation of a Wettable Powder One proceeds as described in Example 13 with the difference that 10 to 20% by weight of a stabilizing acidic buffer substance (such as potassium or sodium dihydrophosphate, lactic acid or tartaric acid) are also added to the composition during the micronizing and homogenization steps. The resulting wettable powder contains about 54 to 76% by weight of active agent.

Example 15 Preparation of a Spray Composition The formula (I) active agent is dissolved in benzene or a homologue thereof (such as toluene or xylene) to form a 0.1 to 1% solution. 1 to 3% of a wetting agent and 1% of a sticker are added to the solution, and the solution is filled into aerosol containers equipped with fine spray nozzles using a propellant gas [such as a Freon gas (Freon is a registered Trade Mark for a normally gaseous mixture of chlorinated and fluorinated aliphatic hydrocarbons), a mixture of propane and butane or carbon dioxide].

Example 16 Preparation of an Emulsifiable Concentrate The formula (I) active agent is powdered until at least 80 /n of the substance has the particle size of 1 to 20y, and the powder is admixed with an equal weight of an inert organic solvent (such as petrol, xylene or diglyme) and 5 to 7% of a wetting agent. The resulting emulsifiable concentrate contains about 47 to 48% by weight of active agent. The concentrate can be diluted to any desired concentration with one of the above inert organic solvent applied.

Example 17 Preparation of Microgranules The formula (I) active agent is dissolved in chloroform (or in another chlorinated hydrocarbon). The solution, the concentration of which depends on the homogenizing technique applied, is applied to the surface of a granular solid support (such as pearlite or coke powder; particle size: 0.1 to 1 mm) according to the "wet" method. Microgranules containing 10 to 30% by weight of active agent are prepared.

Claims (37)

WHAT WE CLAIM IS:

1. A plant protecting composition containing an effective amount of one or more compounds having the general formula (I),

wherein R is a C,~20 alkyl group or a phenyl or phenyl-C, 3 alkylene group having optionally one or inore C13 alkyl and/or halogen substituents on the phenyl ring, together with an adjuvant, diluent or carrier, said composition not being a simple solution of threo-l-phenyl-2-nitro-1,3-propanediol diacetate in an organic solvent free of adjuvants.

2. A composition according to claim 1 comprising a sticker, dispersing agent, surfactant or agent modifying the duration of the pesticidal effect.

3. A composition according to claim I or 2 comprising an acidic stabilizer for said compound of general formula (I).

4. A composition according to claim 3 wherein said acidic stabilizer is sodium or potassium dihydrogen-phosphate, lactic acid or tartaric acid.

5. A composition according to any of the preceding claims wherein said compound of general formula (I) and any other plant protecting agent present comprise 0.01 to 96% by weight of said composition.

6. A composition according to any of the preceding claims in the form of a wettable powder, emulsifiable concentrate, colloidal suspension concentrate, microgranulate or spray.

7. A composition according to any of the preceding claims wherein said compound of general formula (I) is l-phenyl-2-nitro-1,3-propanediol diacetate.

8. A composition according to claim 7 wherein said compound is erythro-lphenyl-2-nitro-1,3-propanediol diacetate.

9. A composition according to claim I, substantially as hereinbefore described.

10. A composition according to claim 1, substantially as hereinbefore described with reference to any one of Examples 13-17.

I 1. A method for the control of fungal, acarid and/or insect pests in a plant locus which comprises applying to said locus an effective amount of a compound of general formula (I) as defined in claim 1.

12. A method according to claim 11 wherein said compound is l-phenyl-2- nitro- I ,3-propanediol diacetate.

13. A method according to claim 11 wherein said compound is erythro-lphenyl-2-nitro-1,3-propanediol diacetate.

14. A method according to any of claims 11-13 wherein a fungal pest is controlled.

15. A method according to any of claims 11-13 wherein an acarid pest is controlled.

16. A method according to any of claims i 11-13 wherein an insect pest is controlled.

17. A method according to any of claims 11-16 wherein said compound is applied to said locus prior to emergence of the plants,

18. A method for stimulating the germination and growth of plants which comprises applying to the locus of said plants an effective amount of a compound as defined in any of claims 1, 7 and 8.

19. A method according to claim 11, substantially as described herein.

20. A method according to claim 18, substantially as described herein.

21. A process for preparing a nitroalcohol derivative of the general formula (I), wherein R is as defined in claim 1, in which l-phenyl-2-nitro-l,3-propanediol of the formula (II)

or an alkali metal salt thereof is treated with an appropriate acylating agent under mild conditions which do not substantially decompose the compounds of general formulae (I) and (it).

22. A process according to claim 21, in which an acid halide and/or an acid anhydride is used as acylating agent.

23. A process according to claim 21, or 22, in which the reaction is performed in the presence of a solvent.

24. A process according to claim 23, in which an alkali metal salt of the formula (II) compound is acylated with an acyl halide in a solvent, at a temperature of about 400 C.

25. A process according to claim 21, in which the reaction is performed without a solvent with an acid anhydride as acylating agent, in the presence of a catalytic amount of a mineral acid or the acid chloride corresponding to the acid anhydride.

26. A process according to any of claims 21 to 25, substantially as hereinbefore described with reference to any of Examples 1 to 12.

27. Compounds of the general formula (I) whenever made by the process of any of claims 21-26.

28. A compound of the general formula (I), wherein R is a C,~20 alkyl group or a phenyl or phenyl-C1~3 alkylene group having optionally one or more C13 alkyl and/or halogen substituents on the phenyl ring, with the proviso that when R is methyl the compound may not be of threo configuration.

29. Erythro-1-phenyl-2-nitro-1,3-propanediol diacetate.

30. The compound of claim 29 in admixture with the threo isomer.

31. 1-Phenyl-2-nitro-1,3-propanediol dipropionate.

32. 1-Phenyl-2-nitro-1,3-propanediol dibenzoate.

33. 1-Phenyl-2-nitro-1,3-propanediol dipalmitate.

34. 1-Phenyl-2-nitro-1,3-propanediol bis(phenylacetate).

35. 1-Phenyl-2-nitro-1,3-propanediol bis(p-chlorobenzoate).

36. Compounds according to claims 31-35 in the threo configuration.

37. Compounds according to claim 28, substantially as described herein.