A bisphosphonic acid and its salt compound, a preparation method and application thereof

Abstract

The application discloses a kind of bisphosphonic acid and its salt compound, preparation method and application.The structural formula of the bisphosphonic acid and its salt compound is as shown in formula (I).The preparation method is to prepare target product [1-hydroxy-3-(methyl phosphine acyl) propyl]-methyl hypophosphorous acid by condensation and hydrolysis two-step reaction with methyl (3-oxo propyl) hypophosphorous acid as starting material, and the target product is reacted with basic substance to obtain corresponding salt.The target product obtained by the application has bisphosphonic acid skeleton, and the novel bisphosphonic acid herbicide lead compound is beneficial to improve weed removal effect;Meanwhile, the salt compound obtained by salifying the target product is used to prepare herbicide for preventing and treating setaria viridis, amaranthus retroflexus, small gooseweed and other weeds, and has obvious weeding effect, and preparing salt can improve water solubility, hygroscopicity, stability and the like of the compound, so as to adapt to different formulation requirements.

Description

Technical Field

[0001] This invention relates to a bisphosphonic acid and its salt compounds, their preparation methods, and their applications in the preparation of herbicides. Background Technology

[0002] In modern agricultural production, weeds are one of the key factors affecting crop growth, development, yield, and quality. Traditional weeding methods, such as manual and mechanical weeding, not only consume a lot of manpower, resources, and time, but are also difficult to implement thoroughly and are inefficient in large-scale agricultural production. Chemical weeding, due to its high efficiency, convenience, and economy, has gradually become the main means of weed control in modern agriculture. Phosphorus-containing compounds hold a unique position in the field of herbicides. Phosphorus can participate in various physiological metabolic processes in organisms, and herbicides designed based on phosphorus-containing structures often have unique targets and mechanisms of action. Some phosphorus-containing herbicides have been widely used in agricultural production, showing good activity and selectivity in controlling specific weed species. However, with the continuous improvement of agricultural production requirements and the intensification of weed resistance problems, it is of great significance to develop new, highly efficient, low-toxicity, environmentally friendly phosphorus-containing herbicides with novel structures and mechanisms of action. This invention provides a novel herbicidal bisphosphonic acid and its salt compounds. Summary of the Invention

[0003] To address the aforementioned problems in the existing technology, the present invention aims to provide a novel, highly efficient, low-toxicity, environmentally friendly bisphosphonic acid and its salt compounds with a novel structure, their preparation method, and their application in the preparation of herbicides.

[0004] This invention defines a bisphosphonic acid and its salt compounds, the general structural formula of which is shown in formula (I):

[0005] ,

[0006] Where: X is H, alkali metal, alkaline earth metal, transition metal, organic amine, or NH4. + The alkali metals include Li, Na, and K; the alkaline earth metals include Be, Ca, and Mg; and the transition metals include Zn, Cu, and Fe.

[0007] Furthermore, the present invention also specifies a method for preparing the aforementioned bisphosphonic acid and its salt compounds, specifically as follows: using methyl (3-oxopropyl)phosphonic acid as shown in formula (II) as the starting material, it is first reacted with diethyl methylphosphonite in the presence of trimethylchlorosilane to generate ethyl (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphonic acid as shown in formula (III). The ethyl (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphonic acid is then acidified in the presence of hydrochloric acid to obtain the product [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid. The product is then reacted with an alkaline substance to synthesize the corresponding bisphosphonate compounds.

[0008] The reaction process is as follows:

[0009] ,

[0010] Furthermore, the present invention also defines a specific process for preparing bisphosphonic acid compounds, comprising the following steps:

[0011] (1) Under nitrogen protection, diethyl methylphosphonite was dissolved in trimethylchlorosilane reagent and stirred at 20℃-30℃ for 10 min. After mixing evenly, the temperature was raised to 40℃, and methyl (3-oxopropyl)phosphonic acid of formula (II) was slowly added. After reacting at this temperature for 30 min, the temperature was raised to 90℃-100℃ and reacted for 1-2 h. After the reaction was completed, the mixture was cooled to room temperature and the low-boiling-point substances generated in the reaction were removed by rotary evaporation to obtain ethyl (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphonic acid of formula (III).

[0012] (2) The ethyl 3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphino acid obtained in step (1) was mixed with water, concentrated hydrochloric acid was added, and then the temperature was gradually raised to 100-110℃ and stirred under reflux for 12-24 h. After rotary evaporation and recrystallization, the product [1-hydroxy-3-(methylphosphono)propyl]-methylphosphino acid was obtained.

[0013] (3) The [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid obtained in step (2) reacts with an alkaline substance. The reaction is completed when the pH is approximately 7. Then, the mixture is cooled to room temperature and dried by rotary evaporation to obtain the corresponding bisphosphonate compound.

[0014] Furthermore, the present invention also specifies that the molar ratio of diethyl methyl phosphite to methyl (3-oxopropyl)phosphonic acid in step (1) is 1:1 to 1.5; and the molar ratio of trimethylchlorosilane agent to diethyl methyl phosphite is 1:1.

[0015] Furthermore, the present invention specifies that the solvent for recrystallization in step (2) is methanol.

[0016] Furthermore, the present invention further specifies that the alkaline substance in step (3) is Li2CO3, NaOH, KOH, CuCO3, CaCO3, MgCO3, Zn(OH)2, ammonia, dimethylamine, diethylamine or isopropylamine.

[0017] Furthermore, the present invention also limits the application of bisphosphonic acids and their salt compounds in the preparation of herbicides.

[0018] Furthermore, the present invention also specifies the use of bisphosphonic acid and its salt compounds in the preparation of herbicides for controlling barnyard grass, crabgrass, foxtail grass, velvetleaf, amaranth, and lambsquarters.

[0019] The present invention defines the specific steps for the sodium bisphosphonate salt compound (I, X=Na) as follows:

[0020] [1-Hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was dissolved in water, and an appropriate amount of NaOH solution was added in batches. The addition was stopped when the pH was approximately 7 after heating the reaction. Then, the solution was cooled to room temperature and dried by rotary evaporation to obtain sodium salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid, the structural formula of which is shown below: .

[0021] The present invention defines the specific steps for the formation of potassium bisphosphonate compounds (I, X=K) as follows:

[0022] [1-Hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was dissolved in water, and an appropriate amount of KOH solution was added in batches. The addition was stopped when the pH was approximately 7 after heating the reaction. Then, the mixture was cooled to room temperature and dried by rotary evaporation to obtain potassium salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid, the structural formula of which is shown below: .

[0023] The present invention defines the specific steps for producing zinc bisphosphonate salt compounds (I, X=Zn) as follows:

[0024] [1-Hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was dissolved in water, and an appropriate amount of Zn(OH)2 was added in batches. The addition was stopped when the pH was approximately 7 after heating the reaction. Then, the mixture was cooled to room temperature and dried by rotary evaporation to obtain zinc salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid, the structural formula of which is shown below: .

[0025] The present invention defines the specific steps for producing bisphosphonate copper salt compounds (I, X=Cu) as follows:

[0026] [1-Hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was dissolved in water, and an appropriate amount of basic copper carbonate was added in batches. The addition was stopped when the pH was approximately 7 after heating the reaction. The mixture was then cooled to room temperature and dried by rotary evaporation to obtain copper salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid, the structural formula of which is shown below: .

[0027] The present invention defines the specific steps for producing bisphosphonate ammonium salt compounds (I, X=NH4) as follows:

[0028] [1-Hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was dissolved in water, and an appropriate amount of ammonia was added in batches. The reaction was heated until the pH was approximately 7, at which point the addition was stopped. The mixture was then cooled to room temperature and dried by rotary evaporation to obtain ammonium salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid, the structural formula of which is shown below: .

[0029] By employing the above-described technology, the beneficial effects of the present invention compared to the prior art are as follows:

[0030] 1) In this invention, two phosphonic acid groups are attached to both ends of the propane chain, and one end has a hydroxyl group. The resulting [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid has a bisphosphonic acid skeleton. This novel bisphosphonic acid herbicide lead compound is beneficial for improving weed removal efficiency.

[0031] 2) In the preparation process of this invention, trimethylchlorosilane is used as a key reagent to promote the condensation reaction of methyl (3-oxopropyl)phosphonic acid and diethyl methylphosphonate. This is the key to constructing the core carbon-carbon bond and forming a specific functional group (trimethylsiloxy group). It only requires two steps to synthesize from the starting material to the final core acid compound. The reaction conditions are mild and the post-processing is convenient, which is conducive to its widespread application.

[0032] 3) This invention yields several different salt compounds, which can alter the water solubility, hygroscopicity, and stability of the compounds, thereby adapting to different formulation needs (such as aqueous solutions, soluble granules, etc.). For example, metal salts such as zinc and copper may have bactericidal or nutritional functions, potentially leading to synergistic effects of weed control, bactericidal / or nutritional action. Furthermore, through salt formation, the toxicity and environmental behavior of the product can be regulated. Attached Figure Description

[0033] Figure 1 This is the proton NMR spectrum (400 MHz, D2O) of the product of Example 4 of the present invention;

[0034] Figure 2 This is the carbon spectrum (400 MHz, D2O) of the product of Example 4 of the present invention;

[0035] Figure 3 This is the phosphorus spectrum (400 MHz, D2O) of the product of Example 4 of the present invention;

[0036] Figure 4 This is the mass spectrum of the product of Example 4 of the present invention;

[0037] Figure 5 This is the mass spectrum of (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphonoethyl ester (III) from Example 1 of the present invention. Detailed Implementation

[0038] The present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0039] Example 1: Synthesis of ethyl (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphinic acid (III)

[0040] Under a nitrogen atmosphere, 1.36 g of diethyl methylphosphite and 1.08 g of trimethylchlorosilane were added to a round-bottom flask and stirred at 20 °C for 10 min to mix evenly. Then, the temperature was raised to 40 °C, and 1.64 g of methyl (3-oxopropyl)phosphonic acid of formula (II) was slowly added dropwise. The mixture was kept warm and stirred for 30 min, and then the temperature was raised to 90 °C and reacted for 1 h. After the reaction was completed, the low-boiling-point substances were removed by rotary evaporation to obtain 1.2 g of ethyl (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphonate of formula (III).

[0041] The mass spectrum of this compound is as follows: Figure 5 As shown, its high-resolution mass spectrum is m / z 245.0700 [M+H]. + (C7H 18 Theoretical value of O5P2 (244.1540), the oxysilyl group breaks down into hydroxyl groups during the reaction.

[0042] Example 2: Synthesis of (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphinic acid ethyl ester (III)

[0043] Under a nitrogen atmosphere, 1.36 g of diethyl methyl phosphite and 1.08 g of trimethylchlorosilane were added to a round-bottom flask. The mixture was stirred at 30 °C for 10 min, then heated to 40 °C, and 1.64 g of methyl (3-oxopropyl)phosphonic acid (as shown in formula (II)) was slowly added dropwise. The mixture was kept at this temperature and stirred for 30 min, then heated to 100 °C and reacted for 1.5 h. After the reaction was completed, the low-boiling-point substances were removed by rotary evaporation to obtain 1.3 g of the compound shown in formula (III).

[0044] Example 3: Synthesis of (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphinic acid ethyl ester (III)

[0045] Under a nitrogen atmosphere, 1.63 g of diethyl methyl phosphite and 1.29 g of trimethylchlorosilane were added to a round-bottom flask. The mixture was stirred at 30 °C for 10 min, then heated to 40 °C, and 1.64 g of methyl (3-oxopropyl)phosphonic acid (as shown in formula (II)) was slowly added dropwise. The mixture was kept at this temperature and stirred for 30 min, then heated to 90 °C and reacted for 2 h. After the reaction was completed, low-boiling-point substances were removed by rotary evaporation to obtain 1.5 g of the compound shown in formula (III).

[0046] Example 4: Synthesis of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid (I, X=H)

[0047] 1.5 g of ethyl 3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphinic acid of formula (III) was added to a round-bottom flask, followed by 10 mL of concentrated hydrochloric acid. The mixture was refluxed at 100 °C for 12 hours. After the reaction was completed, the mixture was evaporated to dryness and 5 mL of methanol solution was added. Crystallization yielded 1.2 g of the target compound [1-hydroxy-3-(methylphosphono)propyl]-methylphosphinic acid.

[0048] Example 5: Synthesis of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid (I, X=H)

[0049] 1.5 g of ethyl 3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphinic acid of formula (III) was added to a round-bottom flask, followed by 10 mL of concentrated hydrochloric acid. The mixture was refluxed at 110 °C for 24 hours. After the reaction was completed, the mixture was evaporated to dryness and 5 mL of methanol solution was added. Crystallization yielded 1.1 g of the target compound [1-hydroxy-3-(methylphosphono)propyl]-methylphosphinic acid.

[0050] Example 6: Synthesis of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid (I, X=H)

[0051] 1.5 g of ethyl 3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphinic acid of formula (III) was added to a round-bottom flask, followed by 10 mL of concentrated hydrochloric acid. The mixture was refluxed at 110 °C for 18 hours. After the reaction was completed, the mixture was evaporated to dryness and 5 mL of methanol solution was added. Crystallization yielded 1.1 g of the target compound [1-hydroxy-3-(methylphosphono)propyl]-methylphosphinic acid.

[0052] This invention determined the structure of the target product [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid by nuclear magnetic resonance (NMR) and mass spectrometry (MS). The spectral data of the compound are as follows:

[0053] like Figures 1-4As shown, the structure of the target product of this invention has been confirmed, with a high-resolution mass spectrometry value of m / z 215.0226 [MH]. - (C5H 14 Theoretical value of O5P2, 216.102); 1 H NMR (400 MHz, D2O) δ 3.63 (m, J = 10.1, 3.4Hz, 1H), 1.98 -1.77 (m, 2H), 1.76 -1.54 (m, 2H), 1.38 - 1.27 (m, 6H). 13 C NMR(101 MHz,D2O) δ 156.21, 69.13, 68.97, 68.00, 67.84, 25.87, 25.75, 24.95,24.83,21.98, 21.94, 21.90, 13.43, 12.51, 10.34, 9.45. 31 P NMR (162 MHz, D2O) δ56.64 (d, J = 5.8Hz), 52.19 (d, J = 6.0 Hz).

[0054] Example 7: Synthesis of sodium salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphinic acid (I, X=Na):

[0055] 1 g of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was added to 2 ml of water and stirred to dissolve. A suitable amount of NaOH aqueous solution was added in batches while stirring. Addition was stopped when the pH was approximately 7. After the addition was complete, the mixture was reacted at 40 °C for 0.5 h. After cooling to room temperature, rotary evaporation was performed to obtain crude sodium [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid. The crude product was dried at 100 °C for 1 hour to obtain sodium [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid.

[0056] Example 8: Synthesis of copper salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphinic acid (I, X=Cu):

[0057] 1 g of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was added to 2 ml of water and stirred to dissolve. A suitable amount of basic CuCO3 was added in batches while stirring. Addition was stopped when the pH reached approximately 7. After the addition was complete, the mixture was reacted at 90 °C for 1 h. After cooling to room temperature, rotary evaporation was performed to obtain crude copper salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid. The crude product was dried at 100 °C for 1 hour to obtain copper salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid.

[0058] Example 9: Synthesis of zinc salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphinate (I, X=Zn):

[0059] 1 g of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was added to 2 ml of water and stirred to dissolve. A suitable amount of Zn(OH)2 powder was added in batches while stirring. Addition was stopped when the pH reached approximately 7. After the addition was complete, the mixture was reacted at 40 °C for 0.5 h. After cooling to room temperature, rotary evaporation was performed to obtain crude zinc salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid. The crude product was dried at 100 °C for 1 hour to obtain zinc salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid.

[0060] Example 10: Synthesis of potassium salt of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphinic acid (I, X=K):

[0061] 1 g of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was added to 2 ml of water and stirred to dissolve. A suitable amount of KOH solution was added in batches while stirring. Addition was stopped when the pH reached approximately 7. After the addition was complete, the mixture was reacted at 40 °C for 0.5 h. After cooling to room temperature, rotary evaporation was performed to obtain crude potassium [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid. The crude product was dried at 100 °C for 1 hour to obtain potassium [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid.

[0062] Example 11: Synthesis of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphinic acid ammonium salt (I, X=NH4):

[0063] 1 g of [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid was added to 2 ml of water and stirred to dissolve. A suitable amount of ammonia was added in batches while stirring. Addition was stopped when the pH reached approximately 7. After the addition was complete, the mixture was reacted at 40 °C for 0.5 h. After cooling to room temperature, rotary evaporation was performed to obtain crude [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid ammonium salt. This crude product was dried at 100 °C for 1 hour to obtain [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid ammonium salt.

[0064] Example 12 Bioactivity Test:

[0065] This invention tests the herbicidal bioactivity of the products of Examples 7-11 according to the "NY / T 1155.4-2006 Guidelines for Indoor Bioassays of Pesticides - Herbicides - Part 4: Activity Assay Test - Foliar Spray Method".

[0066] The specific process of using the novel agricultural antibiotic herbicide of this invention for weed control is as follows:

[0067] Preparation of reagent: Weigh a certain mass of the product of Examples 7-11, dissolve it in water to prepare a 10% mother liquor, and then dilute it with 0.1% Tween-80 water to a concentration of 600 gai / ha for later use.

[0068] Weed targets: barnyard grass, crabgrass, foxtail grass, velvetleaf, amaranth, and lambsquarters.

[0069] Crop targets: soybeans, corn, rapeseed, rice, wheat, sorghum.

[0070] Planting method: Sow several groups of target seeds in plastic pots with a diameter of 8.0cm. After sowing, cover with 0.2-0.5cm of soil, add water to the bottom, and then place in a greenhouse for cultivation. The greenhouse temperature is about 26±2℃.

[0071] Application method: At the 3-4 leaf stage of the target, half of the targets were treated with foliar spray of the product of Examples 7-11 at a concentration of 600 gai / ha, and the other half was the control group. The amount of pesticide was applied quantitatively, and the plants were allowed to stand indoors until the pesticide was absorbed by the leaves. Then the plants were moved into the greenhouse for cultivation and trial harvesting under normal management. The weed control effect was visually assessed 14 days after the application.

[0072] Investigation methods: After the application of the herbicide, the growth of the target plants and the symptoms of poisoning were observed regularly. 14 days after the application, the weed control efficacy and crop safety were visually assessed. The visual assessment method was: experienced testers directly assessed the target plant population in the field to estimate the aboveground coverage or degree of damage. For example, a weed control efficiency of 60% means that the growth of weeds (coverage, growth, etc.) was reduced by about 60% compared with the control group. The weed control activity is shown in Table 1, and the crop safety results are shown in Table 2.

[0073] Table 1. Visually observed control efficacy of the products from Examples 7-11 against six weeds.

[0074]

[0075] The bisphosphonic acid [1-hydroxy-3-(methylphosphonoyl)propyl]-methylphosphonic acid prepared in this invention contains multiple acidic hydroxyl groups and is highly polar. This may make it difficult for it to penetrate the waxy layer and lipid bilayer cell membrane on plant leaves or cell walls, thus failing to reach the target site and having no herbicidal activity against weeds. However, when it is made into a salt compound, it becomes an ionic compound with excellent water solubility. It can be absorbed by plants in the form of aqueous solution and transported and distributed in the plant through the vascular bundle system, eventually reaching the site of action. As can be seen from Table 1, the salt compounds of Examples 7-11 have certain efficacy against barnyard grass, crabgrass, foxtail grass, velvetleaf, amaranth, and lambsquarters. Among them, the copper and zinc salts of Examples 8-9 have a 100% control efficacy against foxtail grass, and the sodium, copper, and zinc salts of Examples 7-9 have a 100% control efficacy against lambsquarters.

[0076] Table 2. Safety results of the products from Examples 7-11 on six crops.

[0077]

[0078] Experiments showed that, 14 days after application, the salt compounds in Examples 7-11 exhibited good growth in crops such as soybeans, corn, rapeseed, rice, wheat, and sorghum, with no signs of poisoning. Therefore, the drug is safe for crops.

[0079] The specific embodiments described in this invention are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

[0080] Although the present invention has been described in detail and specific embodiments have been cited, it will be apparent to those skilled in the art that various changes or modifications can be made without departing from the spirit and scope of the invention.

Claims

1. A bisphosphonate compound, characterized in that, Selected from any of the following chemical structures: 。 2. A method for preparing the bisphosphonate compound as described in claim 1, characterized in that... Starting with methyl(3-oxopropyl)phosphonic acid as shown in formula (II), it is first reacted with diethyl methylphosphonite in the presence of trimethylchlorosilane to generate ethyl (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphonic acid as shown in formula (III). The ethyl (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphonic acid is then acidified in the presence of hydrochloric acid to obtain the product [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid. The product is then reacted with an alkaline substance to synthesize the corresponding bisphosphonate compounds. The reaction process is as follows: 。 3. The method for preparing a bisphosphonate compound according to claim 2, characterized in that... Includes the following steps: (1) Under nitrogen protection, diethyl methylphosphonite was dissolved in trimethylchlorosilane reagent and stirred at 20℃-30℃ for 10 min. After mixing evenly, the temperature was raised to 40℃, and methyl (3-oxopropyl)phosphonic acid of formula (II) was slowly added. After reacting at this temperature for 30 min, the temperature was raised to 90℃-100℃ and reacted for 1-2 h. After the reaction was completed, the temperature was cooled to room temperature, and the low-boiling-point substances generated by the reaction were removed by rotary evaporation to obtain ethyl (3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphonic acid of formula (III). (2) The ethyl 3-(methylphosphono)-1-trimethylsiloxypropyl)-methylphosphino acid obtained in step (1) was mixed with water, concentrated hydrochloric acid was added, and then the temperature was gradually raised to 100-110℃ and stirred under reflux for 12-24 h. After rotary evaporation and recrystallization, the product [1-hydroxy-3-(methylphosphono)propyl]-methylphosphino acid was obtained. (3) The [1-hydroxy-3-(methylphosphono)propyl]-methylphosphonic acid obtained in step (2) reacts with an alkaline substance. The reaction is completed when the pH is approximately 7. Then, the mixture is cooled to room temperature and dried by rotary evaporation to obtain the corresponding bisphosphonate compound.

4. The method for preparing a bisphosphonate compound according to claim 3, characterized in that... In step (1), the molar ratio of diethyl methyl phosphite to methyl (3-oxopropyl)phosphonic acid is 1:1 to 1.5; the molar ratio of trimethylchlorosilane to diethyl methyl phosphite is 1:

1.

5. The method for preparing a bisphosphonate compound according to claim 3, characterized in that... The solvent used for recrystallization in step (2) is methanol.

6. The method for preparing a bisphosphonate compound according to claim 3, characterized in that... The alkaline substances in step (3) are NaOH, CuCO3, and Zn(OH)2.

7. The use of the bisphosphonate compound as described in claim 1 in the preparation of a herbicide, said herbicide being used to control one or more of barnyard grass, crabgrass, foxtail grass, velvetleaf, amaranth, and lambsquarters.

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