Method for producing 1-(2,2-dimethylpropyl)-cyclopropene as a sprayable inhibitor of ethylene action in plants and its use

Abstract

To provide a method of preparing, and use of 1-(2,2-dimethylpropyl)-cyclopropene as sprayable ethylene antagonist in plants and uses thereof.SOLUTION: There are provided a method of preparing, and use of 1-(2,2-dimethylpropyl)-cyclopropene as an ethylene antagonist that can be formulated as an aqueous emulsion and applicable to plants through immersion or spraying. It was confirmed that the compound can be reliably synthesized and stored by the preparation method disclosed herein, and it was also confirmed that the compound can effectively inhibit ethylene action when formulated as an aqueous emulsion and treated to a plant by immersion or spray treatment; hence, the compound may be used as an ethylene antagonist on plants, as a pre-harvest or post-harvest plant growth regulator, or as a freshness keeping agent.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a method for producing 1-(2,2-dimethylpropyl)-cyclopropene (1-DCP), an ethylene action inhibitor that protects plants from the action of ethylene. The compound can be formulated into an aqueous emulsion and applied to plants by immersion or spraying, and the method also relates to uses of the compound. [Background technology]

[0002] Plants have the ability to produce ethylene themselves, and both exogenous and endogenous ethylene have a profound effect on plant growth and development. For example, ethylene exerts physiological functions in plants, such as regulating the release of dormancy and germination in seeds, buds, tuberous roots, tubers, and scales; promoting root growth and adventitious root development; inhibiting gravitropism; inhibiting stem elongation and promoting thickening; regulating flower opening and female and male flower development; promoting leaf, flower, and fruit abscission; increasing respiration; increasing autocatalytic ethylene production; regulating stress tolerance; regulating disease resistance or tolerance; promoting pigment production or decomposition; promoting fruit flesh softening; and regulating aroma production. Ethylene, particularly, is closely related to the senescence of leaves, flowers, and stems, as well as fruit ripening, and is therefore sometimes referred to as the aging hormone or ripening hormone. The negative effects of ethylene action that reduce the economic value of plants include promoting germination of tuberous roots, tubers, and scales, promoting leaf, flower, and fruit abscission, and promoting softening of fruit flesh. Therefore, much research has been conducted into methods for controlling plant responses to ethylene, with the aim of suppressing or blocking such ethylene action.

[0003] There are various methods for controlling plant responses to ethylene. One particularly effective method is to block the effects of ethylene using cyclopropene compounds, including 1-methylcyclopropene (1-MCP). Cycloalkene compounds are generally structurally strained due to their narrower carbon-carbon bond angles compared to open-chain hydrocarbons. Among these, cyclopropenes, with their triangular ring structure, are known to be the most severely strained. The plant response to the hormone ethylene is premised on ethylene binding to the binding site of the ethylene receptor protein distributed in the cell membrane. Cyclopropene compounds, like ethylene, can also bind to the ethylene receptor binding site. However, unlike ethylene, which reversibly binds to the copper ion at the binding site, strained cyclopropene compounds are known to covalently bind to the amino acid residue at the binding site, opening the ring structure upon binding to the receptor protein. This means that, unlike ethylene, cyclopropene compounds bind irreversibly to the binding site of the ethylene receptor and are not redissociated. Therefore, the ethylene receptor bound to a cyclopropene compound can no longer bind ethylene, and is therefore excluded from the ethylene response-related signal transduction pathway.

[0004] Cyclopropene compounds that bind to ethylene receptors and inhibit ethylene responses in plants can be useful for protecting plants from the adverse effects of ethylene. Among cyclopropene compounds, 1-MCP, in particular, has a high binding affinity for ethylene receptors and effectively inhibits ethylene action even at low concentrations, making it widely used as an ethylene antagonist. 1-MCP has a boiling point of 10-12°C and exists as a gas at room temperature. Therefore, it is generally administered to target plants as a gas. A useful method involves sealing harvested target plants in a suitable space and exposing them to a specific concentration of 1-MCP gas for a set period of time. However, to achieve goals for unharvested plants in an open space, such as suppressing flower, leaf, and fruit abscission, delaying ripening, inhibiting senescence, inhibiting ripening, and improving shelf life, a compound that remains liquid at room temperature, can be applied by immersion or spraying, and effectively inhibits ethylene action is required.

[0005] Under these circumstances, the present inventors discovered a compound that can be applied to plants even in open spaces and effectively inhibits the ethylene response, and developed a method for producing and utilizing the compound, thereby completing the present invention. Summary of the Invention [Problem to be solved by the invention]

[0006] One aspect of the present invention provides a method for producing 1-DCP, comprising the steps of: 1) reacting α-DIB (α-diisobutylene) with hypochlorite and an acid to produce α-DIBCl [2-(chloromethyl)-4,4-dimethyl-1-pentene]; 2) reacting the α-DIBCl with an alkali metal alkylamide to produce an alkali metal salt of 1-DCP [1-(2,2-dimethylpropyl)-cyclopropene]; and 3) neutralizing the alkali metal salt of 1-DCP with water or an alcohol to produce 1-DCP, wherein the acid is at least one selected from the group consisting of hydrochloric acid and chlorine-containing Lewis acids.

[0007] In the method, the α-DIB can be obtained by separation from an α / β-isomer mixture containing α-DIB and β-DIB, and the method for obtaining the α-DIB by separation includes the steps of: a) treating an α / β-isomer mixture containing α-DIB and β-DIB with hypochlorite and an acid to produce β-DIBCl; and b) separating α-DIB from the mixture containing the produced β-DIBCl and α-DIB.

[0008] Another embodiment provides a 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene) compound represented by the following chemical formula 1:

[0009] [ka]

[0010] Yet another embodiment provides a 1-DCP inclusion complex comprising 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene) and a cyclodextrin.

[0011] Yet another embodiment provides a method for preparing a 1-DCP inclusion complex, comprising mixing 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene) and a cyclodextrin.

[0012] Yet another embodiment provides a method for preparing a 1-DCP aqueous emulsion, comprising dissolving a 1-DCP inclusion complex in DMSO (dimethyl sulfoxide).

[0013] Yet another embodiment provides an ethylene inhibitor composition comprising 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene), a hydrate thereof, a solvate thereof, a salt thereof, or a complex thereof.

[0014] Yet another embodiment provides a method for inhibiting an ethylene response in a plant, comprising applying to the plant a composition comprising 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene), a hydrate thereof, a solvate thereof, a salt thereof, or a complex thereof. [Means for solving the problem]

[0015] A.1-DCP manufacturing method One aspect of the present invention provides a method for producing 1-DCP, comprising the steps of: 1) reacting α-DIB (α-diisobutylene) with hypochlorite and an acid to produce α-DIBCl (2-(chloromethyl)-4,4-dimethyl-1-pentene); 2) reacting the α-DIBCl with an alkali metal alkylamide to produce an alkali metal salt of 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene); and 3) neutralizing the alkali metal salt of 1-DCP with water or an alcohol to produce 1-DCP, wherein the acid is at least one selected from the group consisting of hydrochloric acid and chlorine-containing Lewis acids.

[0016] The term "1-DCP (1-(2,2-dimethylpropyl)-cyclopropene)" as used herein refers to a cyclopropene compound and is represented by the following chemical formula 1.

[0017] [ka]

[0018] In the method, step 1) is a step of reacting α-DIB (α-diisobutylene) with hypochlorite and acid to produce α-DIBCl (2-(chloromethyl)-4,4-dimethyl-1-pentene), which includes a process shown in Reaction Scheme A below.

[0019] [ka]

[0020] Specifically, step 1) is a method for producing and obtaining α-DIBCl, and includes a) a process of mixing α-DIB with hypochlorite and acid to allylic chlorinate α-DIB to α-DIBCl, and b) a process of separating / obtaining α-DIBCl from the reaction product.

[0021] The α-DIB (α-diisobutylene) is also represented by the following Chemical Formula 2.

[0022] [ka]

[0023] The acid may include one or more selected from the group consisting of hydrochloric acid or chlorine-containing Lewis acids, and may also include one or more selected from the group consisting of FeCl3, AlCl3, CeCl3, and MoCl5.

[0024] According to one embodiment, the acid may include one or more selected from the group consisting of hydrochloric acid, FeCl3, AlCl3, CeCl3, and MoCl5, and may be, specifically, hydrochloric acid.

[0025] The hypochlorite may be an alkali metal hypochlorite or an alkaline earth metal hypochlorite, and specifically may be selected from the group consisting of sodium hypochlorite (NaOCl), potassium hypochlorite (KOCl), lithium hypochlorite (LiOCl), and calcium hypochlorite (Ca(OCl)).

[0026] According to one embodiment, the hypochlorite may be at least one selected from the group consisting of sodium hypochlorite (NaOCl), potassium hypochlorite (KOCl), lithium hypochlorite (LiOCl), and calcium hypochlorite (Ca(OCl)2), and more specifically, may be sodium hypochlorite or calcium hypochlorite.

[0027] In step 1), the mixing ratio (molar) of α-DIB and hypochlorite may be 1:0.2 to 2, specifically 1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, or 1:2.

[0028] In step 1), the mixing ratio (molar) of hypochlorite to acid may be 1.2:0.5 to 2, specifically 1.2:0.5, 1.2:0.7, 1.2:0.9, 1.2:1.1, 1.2:1.3, 1.2:1.5, 1.2:1.7, 1.2:1.9, or 1.2:2.

[0029] In one embodiment, the mixing ratio (molar) of the α-DIB, hypochlorite, and acid is 1:1.2:1.3.

[0030] In the step b), the method for separating / obtaining α-DIBCl from the reaction product can be one of chromatography, solvent extraction, and fractional distillation, and specifically, fractional distillation.

[0031] The α-DIB may be a commercially available product or may be obtained by separation from an α / β-isomer mixture containing α-DIB and β-DIB. The method may include treating an α / β-isomer mixture containing α-DIB and β-DIB with hypochlorite and an acid to produce β-DIBCl, and separating α-DIB from the mixture containing β-DIBCl and α-DIB.

[0032] Specifically, the method for separating and obtaining α-DIB includes: a) mixing an α / β-isomer mixture containing α-DIB and β-DIB with hypochlorite and acid to selectively convert β-DIB into β-DIBCl (1-chloro-2,4,4-trimethyl-2-pentene); and b) separating / obtaining α-DIB from the mixture of α-DIB and β-DIBCl, which may be carried out by the process shown in Reaction Scheme B below.

[0033] [ka]

[0034] The acid may include one or more selected from the group consisting of hydrochloric acid or chlorine-containing Lewis acids, and may also include one or more selected from the group consisting of FeCl3, AlCl3, CeCl3, and MoCl5.

[0035] According to one embodiment, the acid may include one or more selected from the group consisting of hydrochloric acid, FeCl3, AlCl3, CeCl3, and MoCl5, and may be, specifically, hydrochloric acid.

[0036] The hypochlorite may be an alkali metal hypochlorite or an alkaline earth metal hypochlorite, and specifically may be selected from the group consisting of sodium hypochlorite (NaOCl), potassium hypochlorite (KOCl), lithium hypochlorite (LiOCl), and calcium hypochlorite (Ca(OCl)).

[0037] According to one embodiment, the hypochlorite may be at least one selected from the group consisting of sodium hypochlorite (NaOCl), potassium hypochlorite (KOCl), lithium hypochlorite (LiOCl), and calcium hypochlorite (Ca(OCl)2), and more specifically, may be sodium hypochlorite or calcium hypochlorite.

[0038] In the above process, the mixing ratio (molar) of DIB (α / β-isomer mixture) to hypochlorite can be 2:0.5 to 2, specifically 2:0.5, 2:0.7, 2:0.9, 2:1.1, 2:1.3, 2:1.5, 2:1.7, 2:1.9, or 2:2.

[0039] In the above process, the mixing ratio (molar) of hypochlorite to acid may be 1:0.5 to 2, specifically 1:0.5, 1:0.7, 1:0.9, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2.

[0040] In one embodiment, the molar ratio of the DIB, the hypochlorite, and the acid is 2:1:1.

[0041] In the step b), the method for separating / obtaining α-DIB from the mixture of α-DIB and β-DIBCl can be one of chromatography, solvent extraction, and fractional distillation, and specifically, fractional distillation.

[0042] In the above method, step 2) is a step of reacting the α-DIBCl prepared above with an alkali metal alkylamide to prepare a 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene) alkali metal salt, which can be carried out according to the process shown in Reaction Scheme C below. Step 2) may also include an additional step of separating the prepared 1-DCP alkali metal salt.

[0043] [ka]

[0044] Specifically, step 2) includes a) cyclopropenation of α-DIBCl using an alkali metal alkylamide to produce an alkali metal salt of 1-DCP, and b) separation of the alkali metal salt of 1-DCP from the reaction product.

[0045] The α-DIBCl can also be represented by the following chemical formula 3:

[0046] [ka]

[0047] The alkali metal may be lithium (Li), sodium (Na) or potassium (K), and in particular lithium.

[0048] Therefore, the alkali metal salt of 1-DCP produced by the reaction may be at least one selected from the group consisting of lithium salt of 1-DCP, sodium salt of 1-DCP, and potassium salt of 1-DCP, specifically, lithium salt of 1-DCP. The lithium salt of 1-DCP ([2-(2,2-dimethylpropyl)cycloprop-1-en-1-yl]lithium) may also be represented by the following chemical formula 4:

[0049] [ka]

[0050] Step 2) may also include a step of separating the 1-DCP alkali metal salt produced. Specifically, the 1-DCP alkali metal salt produced in step 2) may be separated from the reactants and by-products in a separate process, and the separated 1-DCP alkali metal salt may be used to carry out step 3).

[0051] According to one embodiment, if 1-DCP is produced by immediately reacting the 1-DCP alkali metal salt prepared by reacting α-DIBCl with an alkali metal alkylamide, α-DIB produced during the synthesis process will remain. Although the α-DIB cannot be removed by methods such as distillation, the purity of the final 1-DCP product may be reduced. Therefore, if the 1-DCP alkali metal salt prepared as described above is separated and then 1-DCP is produced based on the separately separated 1-DCP alkali metal salt, a product with significantly higher purity can be obtained.

[0052] The alkali metal alkylamide may include at least one selected from the group consisting of lithium diethylamide, lithium diisopropylamide, sodium diethylamide, sodium diisopropylamide, potassium diethylamide, and potassium diisopropylamide, and specifically may be LDEA (lithium diethylamide) or LDA (lithium diisopropylamide).

[0053] The alkali metal alkylamide may be a ready-made product or may be synthesized.

[0054] The synthesis of the alkali metal alkylamide can be carried out according to the following reaction scheme D.

[0055] [ka]

[0056] In this process, an alkali metal (e.g., lithium) and an alkylamine are reacted with an electron donor to synthesize an alkali metal alkylamide (e.g., lithium alkylamide). The alkylamine can be one of diethylamine (DEA) and diisopropylamine, e.g., DEA. The electron donor can be one of isoprene (ISP) and styrene, e.g., ISP.

[0057] In step b), the method for separating the 1-DCP alkali metal salt (specifically, the lithium salt) from the reaction product also includes filtering the reaction product and evaporating the filtrate under reduced pressure using a rotary evaporator.

[0058] In the above method, step 3) is a step of preparing 1-DCP from the alkali metal salt of 1-DCP, and includes a process as shown in the following reaction formula E.

[0059] [ka]

[0060] The method for producing 1-DCP also includes a) neutralizing a 1-DCP alkali metal salt (specifically, a 1-DCP lithium salt) with water or alcohol to produce 1-DCP, and b) recovering the produced 1-DCP by liquid separation and purifying it by distillation.

[0061] This step may also include washing the neutralized product of the 1-DCP alkali metal salt, specifically washing with hydrochloric acid and / or brine.

[0062] The above step also includes a step of separating / recovering 1-DCP from the neutralization reaction product of the 1-DCP alkali metal salt, specifically, separating 1-DCP via vacuum distillation.

[0063] B. 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene) compound Another aspect provides a 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene) compound represented by the following chemical formula 1. The same as above also applies to this compound: [ka]

[0064] The 1-DCP compound is also produced using the above-mentioned production method.

[0065] C. Preparation of the 1-DCP inclusion complex Yet another embodiment provides a method for preparing a 1-DCP inclusion complex, comprising mixing 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene) with a cyclodextrin. The same applies to this method as described above.

[0066] The method is a process for preparing a stable inclusion complex from 1-DCP, and includes a process as shown in the following reaction formula F. However, the cyclodextrin expressed in the following reaction formula is a schematic diagram rather than a chemical formula.

[0067] [ka]

[0068] The method for preparing the inclusion complex also includes the steps of: (a) dissolving cyclodextrin in a solvent, and then including 1-DCP in the cyclodextrin; and (b) separating the inclusion complex from the solvent, drying it, and then pulverizing it into a solid powder.

[0069] In step a), the cyclodextrin may be one of α-, β-, and γ-cyclodextrin or one of its derivatives, specifically α-cyclodextrin. The cyclodextrin may also include a cyclodextrin mixture, a cyclodextrin polymer, or a modified cyclodextrin. The solvent for dissolving the cyclodextrin may be one of water, urea water, and DMSO (dimethyl sulfoxide), specifically water.

[0070] In step b), the method for separating the inclusion complex can be one of centrifugation and vacuum filtration, specifically vacuum filtration, and the drying method can be one of room temperature drying, hot air drying, and vacuum drying, specifically vacuum drying.

[0071] D.1-DCP inclusion complex Yet another embodiment provides a 1-DCP inclusion complex comprising 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene) and a cyclodextrin. The same applies as above.

[0072] The term "inclusion complex" as used herein refers to a complex compound formed when a host compound forms a one- to three-dimensional molecular-scale space and another guest compound with suitable dimensions and shape is enclosed within it, and is also called a host-guest compound or an inclusion compound.

[0073] The 1-DCP inclusion complex refers to a combination of 1-DCP (guest compound) and cyclodextrin (host compound), where the 1-DCP is located substantially within the internal cavity of the cyclodextrin ring. To form an inclusion complex, the complexed 1-DCP compound must meet size criteria to fit, at least in part, within the internal cavity of the cyclodextrin.

[0074] The cyclodextrin may be one of α-, β-, and γ-cyclodextrin or one of its derivatives, specifically α-cyclodextrin, and may also include cyclodextrin mixtures, cyclodextrin polymers, and modified cyclodextrins.

[0075] The 1-DCP inclusion complex can also be represented by the following chemical formula 5. However, the cyclodextrin represented by the following chemical formula is a schematic diagram rather than a chemical formula.

[0076] [ka]

[0077] The 1-DCP inclusion complex is also produced by the above-mentioned method for producing a 1-DCP inclusion complex.

[0078] E.1-DCP aqueous phase emulsion manufacturing method Yet another embodiment provides a method for preparing an aqueous emulsion of 1-DCP, comprising dissolving the 1-DCP inclusion complex in DMSO (dimethyl sulfoxide). The same applies to this method as described above.

[0079] The method involves dissolving a poorly soluble 1-DCP inclusion complex to prepare a 1-DCP aqueous emulsion, and includes a process shown in the following reaction formula G. However, the cyclodextrin shown in the reaction formula G is a schematic diagram rather than a chemical formula.

[0080] [ka]

[0081] The method for preparing the 1-DCP aqueous phase emulsion also includes the steps of: (a) dissolving the inclusion complex in DMSO (dimethyl sulfoxide) to prepare a 1-DCP / DMSO solution; and (b) mixing the prepared 1-DCP / DMSO solution with water to prepare a 1-DCP aqueous phase emulsion of an appropriate concentration.

[0082] In step a), the ratio (weight / volume) of the inclusion complex to DMSO may be 1:1 to 4, specifically 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.7, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.5, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, or 1:4, and more specifically 1:2.5.

[0083] In the step b), the mixing ratio of water to 1-DCP / DMSO is 100 to 1,000 times (volume).

[0084] The 1-DCP aqueous phase emulsion also contains a surfactant.

[0085] F. Compositions for suppressing plant ethylene responses Yet another embodiment provides a composition for suppressing ethylene responses in plants, comprising 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene), a hydrate thereof, a solvate thereof, a salt thereof, or a complex thereof. The same provisions as those set forth above also apply to the composition.

[0086] The composition is a growth regulator or freshness-maintaining agent that inhibits the ethylene response to plants by applying 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene), its hydrate, solvate, salt, or complex thereof as an active compound.

[0087] The complex also includes a 1-DCP inclusion complex, which is dissolved in a solvent to release the active compound from the inclusion complex and allow the compound to act upon contact with the plant.

[0088] As used herein, the term "ethylene" refers to a gaseous unsaturated hydrocarbon with a C2H4 structure. Exogenous ethylene, or endogenous ethylene produced by plants, has a profound effect on plant growth and development, and is particularly closely related to the senescence of leaves, flowers, stems, etc., and the ripening of fruits, and is therefore also known as the senescence hormone or ripening hormone.

[0089] Ethylene can induce physiological actions in plants, such as breaking dormancy and promoting germination of seeds, sprouts, tuberous roots, tubers, scales, etc., promoting root growth and adventitious root development, suppressing gravitropism, inhibiting stem elongation and promoting thickening, regulating flower opening and female / male flower development, promoting leaf, flower, and fruit abscission, increasing respiration, increasing autocatalytic ethylene production, regulating stress tolerance, regulating disease resistance or tolerance, promoting pigment production or degradation, promoting flesh softening, and regulating aroma production. Therefore, the inhibition of ethylene responses can also suppress one or more of the above physiological actions.

[0090] The composition is also intended to regulate one or more physiological actions in plants selected from the group consisting of dormancy-breaking and germination of seeds, sprouts, tuberous roots, tubers, scales, etc., root growth and adventitious root development, geotropism, stem elongation and thickening, flower opening and female / male flower development, leaf abscission, flower abscission and fruit abscission, respiration, ethylene production, stress tolerance, disease resistance or tolerance, pigment production or decomposition, flesh softening, and fragrance production.

[0091] The composition may be a solid, liquid, or gaseous formulation. The solid, liquid, and gaseous formulations can be prepared by various conventional methods. For example, the active ingredient can be mixed with a solid carrier in the form of a powder, or mixed with a liquid carrier in the form of a mixture, solution, dispersion, emulsion, or suspension, or mixed with a volatile liquid or gaseous carrier in the form of an aerosol to prepare a formulation.

[0092] G. Methods of Inhibiting Ethylene Responses in Plants Yet another embodiment provides a method for inhibiting ethylene responses in plants, comprising applying to the plant a composition containing 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene), a hydrate thereof, a solvate thereof, a salt thereof, or a complex thereof. The same applies to the method as described above.

[0093] The term "plant" is used herein in its general sense and includes, for example, herbaceous plants and woody plants. Plants to be treated by the method of the present invention include the whole plant body or parts thereof, such as seeds, bulbs, tubers, roots, stems, leaves, flowers, fruits, and parts thereof.

[0094] In particular, the plants may be food crops, medicinal crops, specialty crops, edible horticultural crops, ornamental horticultural crops, or landscape crops.

[0095] The composition can be applied to plants by a variety of suitable means. For example, the composition can be applied by contacting the plant to be treated with the composition alone or in a formulation with a carrier. Specifically, the composition can be applied by vaporizing the composition alone or in a formulation in an open or closed space and contacting the plant in gaseous form, by spraying or applying a solid powder formulation and contacting the plant, or by immersing or spraying a liquid formulation and contacting the plant. [Effects of the Invention]

[0096] The present invention provides a method for synthesizing 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene), a compound that suppresses the action of ethylene in plants, and a method for utilizing the same. In the method of the present invention, 1) 1-DCP can be stably synthesized and stored at room temperature, and 2) 1-DCP can be formulated into an aqueous emulsion and then immersed or sprayed onto plants to protect them from the action of ethylene. [Brief explanation of the drawings]

[0097] [Figure 1] 1 shows the results of mass spectrum analysis of α-DIB. [Figure 2] 1 shows chromatograms of gas chromatography analysis of intermediates and products in the process of separating / obtaining α-DIB from the α / β-isomer mixture of DIB. [Figure 3] 1 shows the results of mass spectrum analysis of α-DIBCl. [Figure 4] This is a chromatogram of gas chromatography analysis of intermediate products and products in the process of producing α-DIBCl from α-DIB. [Figure 5] 1 shows the results of mass spectrum analysis of 1-DCP. [Figure 6] This is a chromatogram of gas chromatography analysis of intermediate products and products in the process of producing 1-DCP from 1-DCP lithium salt. [Figure 7]1 is a diagram showing the process from LDEA synthesis to 1-DCP synthesis in Example 1. [Figure 8] 1 is a diagram showing a process of preparing an inclusion complex by including 1-DCP in α-cyclodextrin in Example 2. [Figure 9] FIG. 1 is a graph showing the ripening-inhibitory effect of immersion treatment with a 1-DCP aqueous phase emulsion on banana fruit. [Figure 10] FIG. 1 shows the effect of spray treatment with a 1-DCP aqueous phase emulsion on inhibiting softening of jujube and sweet persimmon fruits. [Figure 11] 1 is a graph showing the results of measuring the change in flesh hardness of jujube and persimmon fruits after spray treatment with a 1-DCP aqueous phase emulsion. DETAILED DESCRIPTION OF THE INVENTION

[0098] The present invention will be described in more detail below through examples, but these examples are for illustrative purposes only and the scope of the present invention is not limited to these examples.

[0099] Unless otherwise specified, the materials used in the following examples were purchased from commercial sources and used without further purification. All solvents were treated by standard methods. Diisobutylene (DaeJung Chemicals and Metals, Korea), calcium hypochlorite (Ca(OCl)2, Samchun Chemicals, Korea), hydrochloric acid (Daejung), lithium (1-6 mm particle size, Thermo-Fisher Scientific, USA), diethylamine (Daejung), isoprene (Samchun), diethyl ether (Daejung), Celite 545, and cyclodextrin (Henrikang Biotech, China) were commercially obtained with reagent grade. Nuclear magnetic resonance ( 1 H NMR and 13 C NMR spectra were obtained in CDCl3 solution by Bruker 500 MHz spectroscopy. NMR chemical shifts were recorded relative to residual CDCl3 (7.25 ppm). Proton-decoupled13 C NMR spectra were obtained at chemical shifts relative to CDCl3 (77.0 ppm). Chromatograms were obtained using a gas chromatograph (Shimadzu GC2010, Japan) equipped with a flame ionization detector (FID) and a capillary column (HP-5, nonpolar, 0.25 mm x 30 m, FT = 0.25 μm). The column temperature was maintained at 60 °C for 2 min and then increased to 200 °C at 25 °C / min. Mass spectra were obtained using a gas chromatograph (Thermo-Fisher TRACE1610) coupled to a mass analyzer (ISQ7610) equipped with a TraceGold-5SiMS (nonpolar, 0.25 mm x 30 m, film thickness = 0.25 mm) capillary column. The oven temperature program started at 50 °C, then gradually increased to 300 °C at 10 °C / min and maintained at 300 °C for 10 min.

[0100] Example 1: Synthesis of 1-DCP The present invention relates to a method for synthesizing 1-(2,2-dimethylpropyl)-cyclopropene (1-DCP), 1-DCP synthesized by the method, and its uses. The overall process for synthesizing 1-DCP is summarized in Reaction Scheme 1 below, and the specific process is as follows:

[0101] [ka]

[0102] 1-1: Separation / harvesting of α-DIB from alpha / β-DIB mixture The process of separating / obtaining α-DIB from an α / β-DIB mixture can be omitted if commercially available α-DIB is obtained and used. DIB (diisobutylene) is commercially available as a 3:1 mixture of α / β-isomers (CAS 25167-70-8) or as isolated α-DIB (CAS 107-39-1), but the isolated product is more than 10 times more expensive than the mixture. Therefore, it is more economical to separate / obtain the isolated product from the mixture rather than obtaining it by itself. Furthermore, the use of a DIB mixture (CAS 107-39-1) in the synthesis of 1-DCP is impractical because it significantly reduces the purity and yield of the final product, 1-DCP.

[0103] The boiling point difference between the α- and β-isomers of DIB is only 1-2°C, making it impossible to separate them by distillation. However, we found that if an α / β-DIB mixture is chlorinated using an appropriate ratio of hypochlorite, β-DIB is chlorinated preferentially over α-DIB and converted to β-DIBCl, which has a much higher boiling point. Therefore, if β-DIB is converted to β-DIBCl and consumed, α-DIB can be recovered from a mixture of α-DIB and β-DIBCl by utilizing the boiling point difference.

[0104] The method for separating / obtaining α-DIB from an α / β-DIB mixture is summarized in the following Reaction Scheme 2, and the specific process is as follows:

[0105] [ka]

[0106] (1) Preparation of hypochlorite aqueous solution: 200 g of calcium hypochlorite (Ca(OCl)2, 70% purity, Samchun Chemicals) was added to 1 L of distilled water, sonicated for 30 minutes, and then centrifuged or refrigerated overnight to settle the insoluble precipitate and recover the supernatant to prepare a hypochlorite aqueous solution. The hypochlorite aqueous solution was then refrigerated and cooled before use.

[0107] (2) 1-L pressure bottle ( max A 328 mL bottle (Duran, Pressure plus bottle, code 10130780) containing 328 mL of chilled DIB (2 mol) (diisobutylene, 3:1 mixture of α- / β-isomers, Daejung Chemicals & Metals) and 511 mL of chilled aqueous hypochlorite solution (1 mol (OCl) - ) was introduced.

[0108] (3) 85.8 mL of chilled concentrated hydrochloric acid (1 mol) (Daejung Chemicals & Metals) was added to the pressure bottle, the stopper was tightly closed, and the mixture was vigorously shaken to mix. During the mixing process, the chlorination of β-DIB occurred, and the reaction was completed within 1 minute. Completion of the reaction was confirmed by the color change of the reaction solution (green to colorless). The hydrochloric acid must be added in a separate, isolated container because the hydrochloric acid added to the pressure bottle only comes into contact with the hypochlorite after the stopper is closed. If the hypochlorite comes into contact with the hydrochloric acid before the stopper is closed, a large amount of chlorine gas will be released, preventing the chlorination reaction. Caution is required as high temperatures (60-70°C) and high pressures (up to 1.5 atmospheres) are generated during the reaction process.

[0109] (4) The reaction mixture was transferred to a 1-L separatory funnel, and the bottom layer (aqueous phase) was removed. The resulting supernatant was refrigerated for 1 hour, and a small amount of water was added and removed to obtain crude α-DIB (328 mL, colorless). This process was repeated six times to obtain approximately 2 L of crude α-DIB.

[0110] (5) Primary fractional distillation: A fractional distillation system was constructed by equipping a 1-L two-necked round flask with a stirring magnet, a Liebig condenser (cooling water temperature: 0°C), a 30 cm Vigreux column, a 200°C thermometer, a heating mantle, and a receiver (500 mL measuring cylinder). The 1 L of crude α-DIB obtained in the previous step was added to the flask and heated for distillation. The solution temperature was maintained at 116-140°C, and the vapor temperature rose to 100-105°C and then dropped to 90-80°C. The primary fractional distillation was terminated when 50% of the distillate was recovered (500 mL recovered, colorless, 93% purity). This process was repeated twice to obtain 1 L of primary distilled α-DIB.

[0111] (6) Secondary fractional distillation: To carry out the secondary fractional distillation of the primary distilled α-DIB obtained in the previous step, 1 L of the primary distilled α-DIB was introduced into a fractional distillation system and heated for distillation. The solution temperature was maintained at 103-130°C, and the vapor temperature increased from 40°C to 93°C and then decreased. The heating temperature was adjusted to maintain a distillation rate of 7-8 mL / min. The secondary fractional distillation was terminated when 90% of the administered amount was recovered in the distillate (900 mL α-DIB, colorless, d = 0.73, purity 98%, final yield 63%).

[0112] 1 H NMR(500MHz, CDCl3)δ 4.83(dd,J=2.5, 1.4Hz, 1H), 4.634.61(m,1H), 1.93(s,2H), 1.77(s,3H), 0.92(s,9H) 13 C NMR (126MHz, CDCl3)δ 144.02, 113.73, 51.66, 31.35, 30.06, 25.27 GCMS[C3H5] + =41, [C4H7] + =55, [C4H9] + =57 base peak, [C5H9] +=69, [C7H 13 ] + =97, [C8H 16 ] + =112 molecular ion peak In the mass spectrum analysis of α-DIB, the molecular ion peak ([CH 16 ] + =112) and base peak ([C4H9] + =57) was shown (Figure 1).

[0113] The purity of the products at each stage of the process was confirmed through gas chromatography analysis (Figure 2).

[0114] In the above process, Ca(OCl)2 can be replaced with other hypochlorites such as NaOCl, but Ca(OCl)2 is more economical, and hydrochloric acid can be replaced with a chlorine-containing Lewis acid (e.g., FeCl3, AlCl3, etc.), but hydrochloric acid is more economical.

[0115] 1-2:α-DIBCl synthesis The method for synthesizing α-DIBCl from α-DIB is summarized in the following reaction scheme 3, and the specific steps are as follows:

[0116] [ka]

[0117] (1) Preparation of hypochlorite aqueous solution: This is the same as the process in 1-1-1 above.

[0118] (2) 1-L pressure bottle ( max In a pressure bottle (Duran, Pressure plus bottle, code 10130780) containing 157 mL of chilled α-DIB (1 mol) and 613 mL of chilled aqueous hypochlorite solution [1.2 mol (OCl)] - At this time, the solution must be cold (0-4°C), otherwise α-DIB will remain.

[0119] (3) 114 mL of chilled concentrated hydrochloric acid (1.3 mol) (Daejung Chemicals & Metals) was added to the pressure bottle, the stopper was tightly closed, and the reaction mixture was mixed by vigorously shaking. During the mixing process, allylic chlorination of α-DIB occurred, completing within 1 minute. Completion of the reaction was confirmed by the color change of the reaction solution (green to colorless). The hydrochloric acid must be added in a separate, isolated container so that the hydrochloric acid added to the pressure bottle would only come into contact with the hypochlorite after the stopper was closed. If the hypochlorite came into contact with the hydrochloric acid before the stopper was closed, a large amount of chlorine gas would be released, preventing the chlorination reaction. High temperatures (60-70°C) and high pressures (up to 1.5 atmospheres) were generated during the reaction process, so they must be removed.

[0120] (4) The reaction mixture was transferred to a 1-L separatory funnel, and the bottom layer (aqueous phase) was removed. The resulting supernatant was centrifuged (3,000-5,000 rpm, 3-5 minutes). A small amount of the precipitated water was added and removed to obtain crude α-DIBCl (160 mL, colorless, 67% yield). Alternatively, anhydrous sodium sulfate powder could be added for dehydration. This process was repeated five times to obtain 800 mL of crude α-DIBCl.

[0121] (5) Fractional distillation: A 1-L two-necked round flask was equipped with a stirring magnet, a Liebig condenser (cooling water temperature: 0°C), a 30 cm Vigreux column, a 200°C thermometer, a heating mantle, and a receiver (500 mL measuring cylinder) to form a fractional distillation system. The 800 mL of crude α-DIBCl obtained in the previous step was added to the flask and heated for distillation. The solution temperature was maintained at 100-120°C, and the vapor temperature rose to 80-85°C and then decreased. The distillation was terminated when 70% of the distillate was recovered (560 mL α-DIBCl, colorless, 80% purity, 78% yield).

[0122] α-DIBCl 1 H NMR(500MHz, CDCl3)δ 5.28(d,J=1.1Hz, 1H), 4.96(s,1H), 4.07(d,J=0.9Hz, 2H), 2.09(s,2H), 0.93(s,9H) 13 C NMR (126MHz, CDCl3)δ 143.24, 118.11, 49.78, 46.35, 31.43, 29.75 In the mass spectrum analysis of α-DIBCl, the molecular ion peak ([CH 15 Cl] + =146) and base peak ([C4H9] + =57) (Figure 3) The purity of the product obtained in the above process was confirmed by gas chromatography analysis (FIG. 4).

[0123] In the above process, Ca(OCl)2 can be replaced with other hypochlorites such as NaOCl, but Ca(OCl)2 is more economical, and hydrochloric acid can be replaced with chlorine-containing Lewis acids (e.g., FeCl3, AlCl3, etc.), but hydrochloric acid is more economical.

[0124] 1-3:1-DCP synthesis Cyclopropene is generally synthesized from allylic halide via α-halogen elimination (α-elimination) using a strong base. The strong base used in this reaction is generally an alkali metal salt of an amine, with sodium amide and lithium diisopropylamide (LDA) being typical examples. For example, 1-MCP (1-methylcyclopropene) can also be synthesized from β-methallylchloride using sodium amide or LDA. However, under the synthesis conditions for 1-DCP, it was found that α-DIBCl does not react with sodium amide but is converted to cyclopropene by a metal salt of an amide containing an alkyl group.

[0125] The synthesis of 1-DCP from α-DIBCl can be summarized in the following reaction schemes 4 to 6. The LDEA (lithium diethylamide) synthesis process in reaction scheme 4 is a process for synthesizing an alkylamide metal salt and can be omitted if commercially available LDA is obtained and used. However, unlike commercially available LDA, LDEA is not commercially available. Using LDEA rather than LDA is advantageous for improving the purity of the final product, 1-DCP. This is because the reaction by-products of LDEA have a lower boiling point than those of LDA, making them easier to remove during the purification process of 1-DCP. Furthermore, since commercially available LDA contains solvents with high boiling points (e.g., cyclohexane) or reaction by-products (e.g., ethylbenzene), using commercially available LDA makes the purification process very difficult. Furthermore, synthesizing LDEA is more economical than obtaining LDA. The specific method for synthesizing 1-DCP from α-DIBCl is as follows.

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129] (1) Synthesis of LDEA (Reaction Scheme 4) 1) A 500 mL three-necked flask was equipped with a Dimroth condenser (cooling water temperature: 0°C), a gas bubbler, a 100°C thermometer, and a heating mantle to form a reaction system.

[0130] 2) A flask was charged with a stirring magnet and 3.51 g of lithium (0.5 mol) (1-6 mm granules, Alfa Aesar), 52.78 mL of DEA (0.5 mol) (diethylamine, Daejung Chemicals & Metals), and 200 mL of diethylether (Daejung Chemicals & Metals). The lithium was drawn into an open lithium reagent bottle while Ar gas was blown into it, and the bottle was quickly weighed. After the lithium was poured into the flask, the flask inlet was quickly sealed with a rubber septum, a needle was inserted, and Ar gas was blown in. This is because if the lithium is exposed to air for a long time and discolors due to reaction with oxygen and moisture, the synthesis of LDEA may be delayed or become unsuccessful.

[0131] 3) Ar gas was bubbled into the flask for 2-3 minutes to remove air, and then 27.79 ml of ISP (0.275 mol) (Isoprene, Samchun Chemicals) was injected all at once using a syringe through the rubber stopper while vigorously stirring the reactants at 800-1,000 rpm using a stirring magnet.

[0132] 4) 2-3 minutes after injecting ISP, the temperature of the reaction solution rose to 38-40°C and boiled down, and the reaction was allowed to proceed under reflux at 35-36°C. After 30-40 minutes, when the consumption of lithium was confirmed, the LDEA synthesis was completed.

[0133] (2) Synthesis of 1-DCP lithium salt (Reaction Scheme 5) 1) In the above process, the flask in which LDEA synthesis was completed was left in a freezer, and then immersed in an ethanol bath cooled to below -40°C, or in a 3:1 mixture of ice and salt (-15°C) to cool the solution to below -10°C.

[0134] 2) Using a syringe, slowly inject 50 mL of α-DIBCl (0.24 mol) into the flask through the rubber stopper. During the injection of α-DIBCl, care must be taken to ensure that the solution temperature does not exceed -10°C. α-DIBCl reacts violently with LDEA, so if α-DIBCl is injected when the solution temperature exceeds -10°C, the solution temperature will rise sharply, causing it to boil over and overflow.

[0135] 3) After the injection of α-DIBCl was completed, the -40°C ethanol bath was replaced with an ice water bath at 0°C. The temperature of the solution in the ice water bath gradually increased, and when the temperature of the solution reached 10-12°C, the formation of a white precipitate (LiCl) began, forming a pure white suspension. The ice water bath was then removed, and the solution was allowed to warm to room temperature while stirring for 15 minutes, completing the synthesis of 1-DCP lithium salt.

[0136] (3) Separation of 1-DCP lithium salt 1) Vacuum filtration: The flask containing the white suspension reaction product was immersed in an ice-water bath to cool it, and then vacuum filtered to remove the white precipitate (LiCl). A clear yellow filtrate containing 1-DCP lithium salt was recovered. A glass fritted funnel was used for vacuum filtration, and Celite 545 (Daejung Chemicals & Metals) was used as a filter aid. Celite must be dried at 120°C for at least two hours before use. If the Celite contains moisture, it will react with the moisture and the resulting 1-DCP lithium salt reaction product will clog the filter pores, making filtration difficult.

[0137] 2) Vacuum evaporation: The yellow filtrate obtained after the vacuum filtration was subjected to a rotary evaporator to remove the solvent and volatile reaction by-products, and 1-DCP lithium salt was recovered (35.4 g, oily, brown). The temperature of the rotary evaporator water bath was gradually increased from room temperature to 50°C, and evaporation was carried out at 50°C for 30 minutes. If the water bath temperature was too low or the evaporation time was too short, reaction by-products may remain in the recovered 1-DCP lithium salt, which may reduce the purity of the final product (1-DCP).

[0138] (4) Synthesis of 1-DCP from 1-DCP lithium salt (Reaction Scheme 6) 1) Neutralization of 1-DCP lithium salt: Approximately 100 mL of distilled water and ice were placed in a 250 mL beaker. While maintaining the water temperature at 0°C and stirring with a magnetic stirrer, the 1-DCP lithium salt synthesized in the previous step was gradually added using a pipette. Because 1-DCP lithium salt reacts violently with water, if the 1-DCP lithium salt is added too quickly or the water temperature is too high, the solution may rapidly increase in temperature, boil over, or even explode. Therefore, more ice was added as the ice melted, maintaining the solution cool while the 1-DCP lithium salt was gradually added.

[0139] 2) The solution was transferred to a 250 mL separatory funnel and the lower layer (aqueous phase) was removed.

[0140] 3) Washing of 1-DCP: The residual liquid (supernatant, dark brown) in the separatory funnel was washed sequentially with approximately 100 mL of dilute hydrochloric acid (approximately 3% HCl) and 100 mL of saturated brine, and then crude 1-DCP (25.4 g, brown) was recovered from the supernatant. The HCl wash was to remove residual amine, and the brine wash was to remove water.

[0141] 4) Vacuum Distillation: A 50 mL two-neck round flask was equipped with a short-path distillation head (cooling water temperature: -10 to 0°C), a receiver (cooled in an ethanol bath at -40 to -20°C), a 100°C thermometer, a heating mantle, and a vacuum line to form a vacuum distillation system. Crude 1-DCP (25.4 g) synthesized in the previous step was added to the flask and heated under reduced pressure of 5 to 10 mBar for distillation. The solution temperature dropped to 5 to 10°C and then gradually rose. When the solution temperature reached 35°C, the distillation was stopped and 1-DCP was recovered (9 g 1-DCP, colorless, d = 0.77, bp = 115 to 120°C, purity 95%, yield 35%).

[0142] 1 H NMR(500MHz, CDCl3)δ 6.526.49(m,1H), 2.39(d,J=0.8Hz, 2H), 0.99(s,9H), 0.90(d,J=1.9Hz, 2H) 13 C NMR (126MHz, CDCl3)δ 118.96, 99.06, 40.78, 30.03, 29.55, 5.91 In the mass spectrum analysis of 1-DCP, the molecular ion peak ([CH 14 ] + =110) and base peak ([C4H9] + =57) (Figure 5) The purity of the products obtained in the above process was confirmed by gas chromatography (FIG. 6), and the synthesis process of 1-DCP is shown in FIG.

[0143] Example 2: Preparation of cyclodextrin inclusion complex of 1-DCP The 1-DCP synthesized in Example 1 could be stored in a freezer at -40°C for several months or more, but polymerization occurred within a few days under refrigerated conditions, making it impossible to store for more than a day at room temperature. However, it was discovered that if 1-DCP is included in cyclodextrin to form a complex, 1-DCP can be stably stored for several months or more even at room temperature.

[0144] 2-1: Preparation of α-cyclodextrin inclusion complex The method for preparing an inclusion complex of 1-DCP using α-cyclodextrin, which is relatively soluble in water (solubility 140 g / L), is summarized in the following reaction scheme 8, and the specific steps are as follows: Note that the α-CD shown in the following reaction scheme is a schematic diagram rather than a chemical formula.

[0145] [ka]

[0146] (1) Preparation of α-cyclodextrin solution: 1-L pressure bottle ( max 400 mL of distilled water and 40 g of α-CD (α-cyclodextrin, Henrikang Biotech) were placed in a pressure bottle (Duran, Pressure Plus bottle, code 10130780) under a pressure of 1.5 bar (P = 1.5 bar). The bottle was then capped and vigorously shaken to dissolve the α-CD. The pressure bottle was then vacuumed and released five times to degas the α-CD solution.

[0147] (2) 5 mL of 1-DCP obtained in the previous step was added to the α-CD aqueous solution, and after closing the stopper, the container was vigorously shaken for 15 minutes, at which point an inclusion complex of 1-DCP and α-CD was formed in the form of a white precipitate.

[0148] (3) The suspension containing the white precipitate was vacuum filtered using a Buchner funnel (Whatman filter paper, grade 3, particle retention 6 μm, thickness 390 μm), and the white precipitate (inclusion complex crystals) was collected as a filter cake. The collected white precipitate was sealed in a desiccator and vacuum dried at room temperature for 24 hours to remove moisture. The precipitate was then ground in a mortar or an electric coffee grinder to produce a solid powder of the inclusion complex (1-DCP / α-CD molar ratio = 0.73, 1-DCP content = 92 μL / g). The preparation process of the 1-DCP α-cyclodextrin inclusion complex is shown in Figure 8.

[0149] 2-2: Preparation of β-cyclodextrin inclusion complex Cyclodextrins synthesized from starch using enzymes are produced in three types: α-, β-, and γ-types. Of these, the β-type is the most commonly produced and therefore the cheapest of the three. Therefore, the use of β-cyclodextrin is economically advantageous in the preparation of inclusion complexes. However, the β-type has the problem of being much less soluble in water than the α-type.

[0150] However, we discovered that 1-DCP inclusion complexes can be formed by dissolving β-cyclodextrin in DMSO (dimethyl sulfoxide) instead of water. The method for preparing an inclusion complex of 1-DCP by dissolving β-cyclodextrin in DMSO is summarized in Reaction Scheme 9 below, and the specific process is as follows. However, the β-CD shown in the following reaction scheme is a schematic diagram rather than a chemical formula.

[0151] [ka]

[0152] (1) Preparation of β-cyclodextrin solution: 10 g of β-CD (β-cyclodextrin hydrate, Samchun Chemicals) and 10 mL of DMSO (dimethyl sulfoxide) were placed in a 40 mL vial, and the mixture was vigorously mixed using a vortex mixer to dissolve the β-CD.

[0153] (2) 1 mL of 1-DCP obtained in the previous step was added to the β-CD solution, the stopper was closed, and the solution was shaken vigorously for 15 minutes.

[0154] (3) When the solution was mixed with 100 mL of distilled water, a white suspension immediately formed. The suspension was centrifuged to collect a white precipitate (inclusion complex). The collected white precipitate was vacuum dried at 30°C to remove water and then ground in a mortar to produce a solid powder (4 g) of 1-DCP / β-CD inclusion complex. However, analysis of the 1-DCP inclusion amount in the inclusion complex revealed that it was 17 μL / g, which was significantly lower than that of α-CD (92 μL / g).

[0155] Example 3: Dissolution of 1-DCP inclusion complex and preparation of aqueous emulsion To release 1-DCP from the α-CD inclusion complex of 1-DCP prepared in Example 2 and apply it to target plants, it must be dissolved in water to form an aqueous solution. However, the cyclodextrin inclusion complex of 1-DCP has very low solubility in water, making it impossible to dissolve it and prepare a solution containing 1-DCP at a concentration suitable for plant treatment. However, we found that the 1-DCP / α-CD inclusion complex was easily dissolved in DMSO (dimethyl sulfoxide) at a ratio of 4 g / 10 mL. By first dissolving the 1-DCP inclusion complex in DMSO and then mixing it with water, we were able to prepare an aqueous emulsion containing 1-DCP at an appropriate concentration.

[0156] The method of dissolving the 1-DCP inclusion complex in DMSO and mixing it with water is also summarized in the following reaction scheme 10, and the specific process is as follows: Note that the cyclodextrin shown in the following reaction scheme is a schematic diagram rather than a chemical formula.

[0157] [ka]

[0158] (1) 4 g of 1-DCP / α-CD inclusion complex (containing 368 μL of 1-DCP) and 10 mL of DMSO were placed in a 20 mL vial, and the mixture was subjected to ultrasonic dissolution and vigorous shaking for 2 to 3 minutes to dissolve the inclusion complex, thereby preparing a 1-DCP / DMSO solution (12.7 mL).

[0159] 2) The 1-DCP concentration of the 1-DCP / DMSO solution was 200 mM, and by mixing it with water at a 400-fold (0.5 mM) or 200-fold (1 mM) dilution, a 0.5-1 mM aqueous phase emulsion of 1-DCP was prepared, which is a concentration suitable for treating plants.

[0160] Example 4: Treatment effect of 1-DCP on plants In order to evaluate the ethylene action inhibitory effect of 1-DCP synthesized in the above example, the following experiment was carried out.

[0161] 4.1: Effect of 1-DCP soaking treatment on banana fruit To evaluate the ethylene suppression effect of 1-DCP immersion treatment, the following experiment was conducted.

[0162] Specifically, unripe bananas were harvested from a banana farm in Sancheonggun, South Gyeongsang Province, and on the day they were delivered to the laboratory, they were divided into two groups. Group A (control) (16 fruits) was immersed in a 0.025% wetting agent (Cover, Farm Hannog) solution containing no 1-DCP, while Group B (treatment) (16 fruits) was immersed in a 1 mM 1-DCP aqueous emulsion for 1 second to wet the surface, then allowed to dry at room temperature. The following day, half of the fruits (8 fruits each) from Group A and Group B were placed in two 40 L containers, sealed, and then ethylene gas was injected. The fruits were exposed to 10 ppm ethylene for 24 hours. The treated bananas were then stored at room temperature and observed for ripening after 7 and 14 days.

[0163] The results of the experiment showed that fruits in Group A exposed to ethylene turned yellow within 7 days and blackened within 14 days, whereas fruits in Group B soaked in 1-DCP remained less ripe than the control fruits in Group A until the 14th day, despite being exposed to ethylene (Figure 9).

[0164] Banana fruits are known to be sensitive to ethylene and exhibit accelerated ripening. As a result of the above experiment, it was confirmed that 1-DCP effectively inhibits the action of ethylene in banana fruits when soaked at concentrations of 1 mM or less.

[0165] 4.2: Effect of spray treatment of 1-DCP on jujube persimmon fruit To evaluate the ethylene suppression effect of 1-DCP spray treatment, the following experiment was conducted.

[0166] Specifically, four sweet persimmon trees of jujube cultivars were selected on October 7th at the Sweet Persimmon Research Institute orchard in Jinyong-eup, South Gyeongsang Province. Fruit growing on two of the trees (control group) was treated with a solution containing 0.025% wetting agent (Cover, Farm Hannog), while fruit growing on the other two trees (treatment group) was treated with a spray treatment using a manual sprayer with an aqueous emulsion containing 1 mM 1-DCP and 0.025% wetting agent. Fruit from each treatment group was harvested on October 24th and stored at room temperature. Changes in flesh firmness were measured / observed after 7 and 14 days.

[0167] As a result of the above experiment, after 7 days of storage at room temperature, the flesh firmness of the untreated and 1-DCP-treated fruits was measured at 20.2 N and 19.5 N, respectively, and no significant difference was found between the treatments. However, after 14 days of storage at room temperature, the flesh firmness was measured at 4.3 N and 11.9 N in the control and treated groups, respectively. The control fruit had softened considerably, with the flesh becoming extremely soft, while the 1-DCP-treated fruit maintained a relatively firm flesh (Figures 10 and 11).

[0168] Generally, fruit flesh softening is a phenomenon caused by the action of ethylene. As a result of the above experiment, it was confirmed that 1-DCP effectively inhibited the action of ethylene in jujube fruit when sprayed at a concentration of 1 mM or less.

[0169] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not limiting.

Claims

[Claim 1] A method for producing an aqueous emulsion of 1-DCP (1-(2,2-dimethylpropyl)-cyclopropene), comprising the steps of: a) dissolving 1-DCP inclusion complex in DMSO (dimethyl sulfoxide) at a ratio (g / ml) of 1:1 to 1:4 to prepare a 1-DCP / DMSO solution; b) mixing the prepared 1-DCP / DMSO solution with water in a volume ratio of 1:100 to 1:1000 to form a 1-DCP aqueous phase emulsion; The method of manufacturing, wherein the 1-DCP inclusion complex comprises 1-DCP and a cyclodextrin.

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