Resin-supported cyclic tellurium compound

Abstract

To provide a resin-supported cyclic tellurium compound, and to provide a method for effectively forming an intramolecular or intermolecular disulfide bond, which uses the resin-supported cyclic tellurium compound, and a method for effectively producing a compound having an intramolecular or intermolecular disulfide bond, which includes the method.SOLUTION: There is provided a resin-supported cyclic tellurium compound. The resin-supported cyclic tellurium compound is used as a catalyst of formation reaction of an intramolecular or intermolecular disulfide bond.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a resin-supported cyclic tellurium compound. The present disclosure also relates to a method for forming a disulfide bond in a target compound using the resin-supported cyclic tellurium compound as a catalyst, and a method for producing a compound having a disulfide bond using the method.

Background Art

[0002] In an organic compound having a thiol (SH) group, appropriately forming an intramolecular or intermolecular disulfide (SS) bond is important in terms of molecular conformation control, reversible coupling, thiol group protection, etc. In addition, many proteins or peptides exhibit physiological functions when intramolecular or intermolecular disulfide bonds are appropriately formed. In particular, in the case of proteins, it is important that intramolecular or intermolecular disulfide bonds are appropriately formed in forming the higher-order structure necessary for the protein to exhibit physiological functions. Therefore, for example, when artificially synthesizing a protein or peptide by genetic engineering techniques or organic chemical techniques, it is important to appropriately form an intramolecular or intermolecular disulfide bond in the synthesized protein or peptide. Furthermore, in applications where a disulfide bond that does not exist naturally is introduced into a target compound (for example, a protein or peptide) to modify the function of the target compound, or a drug or the like is conjugated to modify or expand the function of the target compound, or a labeling compound is conjugated to facilitate the detection of the target compound, the disulfide bond can be effectively utilized.

[0003] From a chemical perspective, the disulfide bond formation reaction is a two-electron oxidation reaction that occurs between a pair of thiol groups. As classical inorganic / organic oxidants that can be used in this method, iodine, permanganate, sodium perborate, iron(III) chloride, dimethyl sulfoxide, etc. are known. However, these classical inorganic / organic oxidants have low chemoselectivity and are not suitable for use in oxidizing thiol groups chemoselectively to form disulfide bonds in proteins and peptides with many reactive functional groups.

[0004] For the formation of disulfide bonds in proteins and peptides, generally, SS oxidants such as trans-4,5-dihydroxy-1,2-dithiane (DTTox) and oxidized glutathione (GSSG) are used. These SS oxidants can oxidize thiol groups chemoselectively. However, these SS oxidants generally have poor reaction efficiency, and to achieve an appropriate reaction rate and yield, it is necessary to use a large excess (10 - 100 times) in molar ratio relative to the thiol groups. Also, since the oxidation reaction of thiol groups by SS oxidants generally needs to be carried out under neutral to weakly basic conditions where the thiol group is converted to the active thiolate anion, it is not suitable for use in forming disulfide bonds in proteins and peptides that are only soluble in acidic solvents.

[0005] Also, in the reaction to form a disulfide bond from a thiol group, generally, a purification step (for example, a purification step using HPLC) is required to remove by-products derived from the reagents used and unreacted compounds.

[0006] Reagents and methods that can more effectively carry out the disulfide bond formation reaction in the target compound have been studied. For example, Non-Patent Document 1 discloses a cyclic tellurium compound. Also, Non-Patent Document 1 discloses that by using this cyclic tellurium compound as a catalyst, the disulfide bond formation reaction was effectively carried out, especially in low-molecular-weight organic compounds.

Prior Art Documents

Non-Patent Literature

[0007]

Non-Patent Literature 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] This disclosure aims to provide a novel resin-supported cyclic tellurium compound. Another aim is to provide a method for effectively forming intramolecular or intermolecular disulfide bonds using the resin-supported cyclic tellurium compound, and a method for effectively producing a compound having an intramolecular or intermolecular disulfide bond, which includes the said method.

Means for Solving the Problems

[0009] This disclosure provides the following resin-supported cyclic tellurium compound. Formula 1: TIFF2025109012000002.tif43170 [In Formula 1, L is a linker and X is a resin moiety] a structure represented by, or Formula 2: TIFF2025109012000003.tif35170 [In Formula 2, L is a linker and X is a resin moiety] a structure represented by a resin-supported cyclic tellurium compound having

Advantages of the Invention

[0010] According to this disclosure, a novel resin-supported cyclic tellurium compound can be provided. Also, according to this disclosure, by using the novel resin-supported cyclic tellurium compound as a catalyst, the disulfide bond formation reaction in a substrate compound can be effectively carried out.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described in detail. However, the scope of the present disclosure is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. When a specific description given for one embodiment also applies to other embodiments, the description may be omitted in other embodiments.

[0013] <Resin-Supported Cyclic Tellurium Compound> In one embodiment, Formula 1: TIFF2025109012000004.tif43170 [In Formula 1, L is a linker, and X is a resin moiety] a structure represented by, or Formula 2: TIFF2025109012000005.tif35170 [In Formula 2, L is a linker, and X is a resin moiety] a structure represented by A resin-supported cyclic tellurium compound having is provided. This resin-supported cyclic tellurium compound can be effectively used as a catalyst, for example, in a method for forming at least one intramolecular disulfide bond in a compound containing at least one pair of thiol groups, or in a method for forming an intermolecular disulfide bond between a first compound containing at least one thiol group and a second compound containing at least one thiol group. Details of these will be described below.

[0014] The resin-supported cyclic tellurium compound having the structure represented by Formula 1 is Formula 3: TIFF2025109012000006.tif42170 [In Formula 3, L is a linker and X is a resin moiety] a resin-supported cyclic tellurium compound having the structure represented by Formula 4: TIFF2025109012000007.tif42170 [In Formula 4, L is a linker and X is a resin moiety] a resin-supported cyclic tellurium compound having the structure represented by, or a mixture of these resin-supported cyclic tellurium compounds may be.

[0015] The resin-supported cyclic tellurium compound having the structure represented by Formula 2 is Formula 5: TIFF2025109012000008.tif38170 [In Formula 5, L is a linker and X is a resin moiety] a resin-supported cyclic tellurium compound having the structure represented by Formula 6: TIFF2025109012000009.tif38170 [In Formula 6, L is a linker and X is a resin moiety] a resin-supported cyclic tellurium compound having the structure represented by, or a mixture of these resin-supported cyclic tellurium compounds may be.

[0016] The resin-supported cyclic tellurium compound is a compound in which the cyclic tellurium compound is supported on a resin moiety via a linker. The linker may be any linker within the scope where the effects of the present invention can be obtained, preferably -NHCO-, -CONH-, -OCO-, or -COO-, more preferably -NHCO- or -CONH-, and particularly preferably -NHCO-. The linker is preferably formed by the condensation of a functional group that binds to a hetero 5-membered or 6-membered ring containing tellurium and a functional group that binds to the resin. For example, in a resin-supported cyclic tellurium compound prepared by the condensation of an -NH2 group that binds to a hetero 5-membered or 6-membered ring containing tellurium and a -COOH group that binds to the resin moiety, the linker is -NHCO-.

[0017] The resin moiety contains a resin and is a moiety capable of supporting a tellurium compound. As the resin, a known resin that is insoluble in the reaction solvent and suitable for solid-phase chemical synthesis is preferably used. Non-limiting examples of the resin include polystyrene resin, polyacrylamide resin, and resins based on these. The resin is preferably a bead-shaped resin with a small particle size (e.g., particle size 30 - 300 μm). The resin part may be a part containing a polystyrene resin grafted with polyethylene glycol (for example, having a molecular weight of 3,000 to 4,000). Non-limiting examples of such a resin part include a resin part containing NovaSyn™ TG resin. Products in which reactive functional groups (for example, carboxy group, amino group, hydroxy group) for binding to a compound to be supported are introduced into the resin part are commercially available. Non-limiting examples of such products include, in the above-mentioned NovaSyn™ TG resin, NovaSyn™ TG carboxy resin (Merck), NovaSyn™ TG amino resin HL (Merck), PAL-NovaSyn™ TG resin (Merck), NovaSyn™ TG hydroxy resin (Merck), NovaSyn™ TG HMBA resin (Merck), NovaSyn™ TG PAP resin (Merck), NovaSyn™ TG bromo resin (Merck), 4-Sulfamylbutyryl NovaSyn™ TG resin (Merck), NovaSyn™ TG Sieber resin (Merck), etc., which are resins in which a functional group is introduced at the terminal of polyethylene glycol.

[0018] The resin-supported cyclic tellurium compound can be prepared, for example, by binding a cyclic tellurium compound prepared by the method described in K. Arai et al., Catal. Sci. Technol., 2019, Vol. 9, pp. 3647-3655, and a known resin part by a known method. For example, as the tellurium compound, Formula 7: An example of a preparation scheme of a resin-supported cyclic tellurium compound when the cyclic tellurium compound represented by TIFF2025109012000010.tif43170 is used and NovaSyn™ TG carboxy resin (Merck) is used as the resin part is shown in Figure 2. In the preparation scheme of FIG. 2, an amino group of the cyclic tellurium compound and a carboxy group of the NovaSyn™ TG carboxy resin are condensed to form an amide bond by reacting the cyclic tellurium compound and the NovaSyn™ TG carboxy resin in a DMF solvent in the presence of a condensing agent (PyBop™ and DIPEA in FIG. 2), thereby forming a resin-supported cyclic tellurium compound.

[0019] <Method for forming a disulfide bond> In certain embodiments, A method for forming at least one intramolecular disulfide bond in a compound containing at least one pair of thiol groups, the method comprising oxidizing at least one pair of thiol groups with an oxidizing agent using a resin-supported cyclic tellurium compound as a catalyst to form at least one intramolecular disulfide bond from the at least one pair of thiol groups. is provided. Also provided is a method for producing a compound having at least one intramolecular disulfide bond, the method comprising forming at least one intramolecular disulfide bond by this method (hereinafter also referred to as the intramolecular disulfide bond formation method). In another embodiment, A method for forming an intermolecular disulfide bond between a first compound containing at least one thiol group and a second compound containing at least one thiol group, the method comprising oxidizing at least one thiol group contained in the first compound and at least one thiol group contained in the second compound with an oxidizing agent using a resin-supported cyclic tellurium compound as a catalyst to form at least one intermolecular disulfide bond from the thiol group contained in the first compound and the thiol group contained in the second compound. is provided. Also provided is a method for producing a third compound in which a first compound and a second compound are bonded by at least one intermolecular disulfide bond, the method comprising forming at least one intermolecular disulfide bond between the first compound and the second compound by this method (hereinafter also referred to as the intermolecular disulfide bond formation method).

[0020] The method for forming intramolecular or intermolecular disulfide bonds of the present disclosure can effectively carry out a reaction (disulfide formation reaction) for forming one disulfide bond from a pair of thiol groups by using a resin-supported cyclic tellurium compound as a catalyst. Fig. 1 shows an example of a disulfide bond formation reaction using a resin-supported cyclic tellurium compound as a catalyst. In the reaction shown in the figure, first, by reaction 1, the resin-supported cyclic tellurium compound in the solid phase is oxidized by an oxidizing agent (ROOH (R is hydrogen or an alkyl group) in Fig. 1), and is converted from a reduced telluride form to an oxidized telluroxide form. Subsequently, by reaction 2, the resin-supported cyclic tellurium compound in the telluroxide form oxidizes a pair of thiol groups contained in the compound (peptide in Fig. 1) in the liquid phase as the substrate, and forms one disulfide bond in the peptide molecule. At this time, the resin-supported cyclic tellurium compound in the telluroxide form is reduced and converted to the telluride form. The resin-supported cyclic tellurium compound functions as a catalyst in the disulfide bond formation reaction by repeating this cycle. This catalytic cycle is similar to the catalytic cycle of glutathione peroxidase (GPx) in vivo.

[0021] The method for forming intramolecular or intermolecular disulfide bonds of the present disclosure can carry out the disulfide bond formation reaction rapidly and chemoselectively. Further, since the method for forming intramolecular or intermolecular disulfide bonds of the present disclosure can carry out the disulfide bond formation reaction in a solid-liquid two-phase system, after the reaction, by simply removing the solid phase by filtration or the like, the product in which the disulfide bond is formed in the liquid phase can be easily and rapidly separated from the resin-supported cyclic tellurium compound in the solid phase and recovered.

[0022] In the method for forming intramolecular or intermolecular disulfide bonds of the present disclosure, since the resin-supported cyclic tellurium compound is regenerated by a glutathione peroxidase (GPx)-like catalytic cycle during the disulfide bond formation reaction, it can be reused in the next reaction. That is, in the method for forming intramolecular or intermolecular disulfide bonds of the present disclosure, a step of forming a disulfide bond by reusing the resin-supported cyclic tellurium compound may be carried out. In this case, the number of times the resin-supported cyclic tellurium compound is used in the step of forming a disulfide bond may be 2 or more, 3 or more, or 4 or more. Even when the resin-supported cyclic tellurium compound is reused as a catalyst, the generation of by-products is small, and the conversion efficiency from a thiol group to a disulfide bond is also good. When the resin-supported cyclic tellurium compound is reused as a catalyst, the conversion efficiency from a thiol group to a disulfide bond is preferably 70% or more, more preferably 75% or more when used twice, preferably 50% or more, more preferably 55% or more when used three times, and preferably 35% or more, more preferably 40% or more when used four times.

[0023] As the oxidizing agent, any oxidizing agent can be used within the range where the effects of the present invention can be obtained. The oxidizing agent is preferably ROOH [R is hydrogen or a C1-C6 alkyl group], metachloroperbenzoic acid, or urea hydrogen peroxide, more preferably ROOH [R is hydrogen or a C1-C6 alkyl group], and particularly preferably hydrogen peroxide or t-butyl hydroperoxide. By using these oxidizing agents, the disulfide bond reaction can be effectively carried out easily.

[0024] In the method for forming an intramolecular disulfide bond in the present disclosure, as the compound containing at least one pair of thiol groups, any compound can be used within the range where the effects of the present invention can be obtained. Non-limiting examples of the compound containing at least one pair of thiol groups include lipophilic or water-soluble low molecular weight (for example, molecular weight 1000 or less) organic compounds, proteins, or peptides.

[0025] In the method for forming an intermolecular disulfide bond of the present disclosure, any compound can be used as the first compound and the second compound within the range where the effects of the present invention can be obtained. Non-limiting examples of the first compound and the second compound include lipophilic or water-soluble low molecular weight (for example, molecular weight of 1000 or less) organic compounds, proteins or peptides. The first compound and the second compound may be the same compound or different compounds.

[0026] When both the first compound and the second compound are proteins or peptides, the disulfide bond between the first compound and the second compound may bond between subunits of a protein constituting a certain quaternary structure, or may bond proteins or peptides derived from different sources to form a fusion protein or peptide. When either one of the first compound and the second compound is a protein or peptide, the other may be an agent that modifies or modifies the function of the protein or peptide, or a labeling compound (for example, a dye, a fluorescent compound, a chemiluminescent compound, a radioactive compound, an affinity tag) that facilitates the detection of the protein or peptide.

[0027] When the substrate of the method for forming an intramolecular disulfide bond is a protein or peptide, or when the substrate of the method for forming an intermolecular disulfide bond contains a protein or peptide, since a large number of reactive functional groups are contained in the protein or peptide, it is not always easy to chemically selectively oxidize a thiol group from among these many reactive functional groups to form a disulfide bond. Furthermore, in the case of a protein that forms a higher-order structure, in order to prevent the protein from denaturing, it is important to avoid the step of contacting with an organic solvent and to carry out the reaction and recovery of the reaction product in an aqueous solvent. According to the method for forming intramolecular or intermolecular disulfide bonds of the present disclosure, even when the substrate is a protein or peptide containing a large number of reactive functional groups, it is possible to chemoselectively oxidize the thiol groups in the protein or peptide. Further, since the method for forming intramolecular or intermolecular disulfide bonds of the present disclosure can be carried out in a solid-liquid two-phase system using only a single solvent, by using the single solvent as an aqueous solvent, even when the substrate is a protein, it is possible to effectively carry out the reaction and recover the reaction product without adversely affecting the higher-order structure of the protein. The "aqueous solvent" is a solvent mainly composed of water and may contain various additives (for example, pH buffers, salts, stabilizers, surfactants, etc.).

[0028] The reaction solvent used in the disulfide bond formation reaction is arbitrary within the range where the effects of the present invention can be obtained. Non-limiting examples of solvents that can be used when the target compound is a lipophilic low-molecular-weight organic compound include methanol, ethanol, acetonitrile, ethyl acetate, chloroform, or dichloromethane. Non-limiting examples of solvents that can be used when the target compound is a water-soluble low-molecular-weight organic compound or a peptide include aqueous TFA solutions (for example, 0.1%) and hydrochloric acid (for example, 10 mM). Non-limiting examples of solvents that can be used when the target compound is a protein include buffers that can maintain an appropriate pH for the formation of the higher-order structure of the protein. The buffer may contain various additives (for example, salts, stabilizers, surfactants, etc.). The reaction solvent can be used in any amount within the range where the effects of the present invention can be obtained. For example, for 1 mg of the resin-supported cyclic tellurium compound, preferably 0.1 to 5.0 μL, more preferably 0.2 to 3.0 μL, and particularly preferably 0.5 to 2.7 μL of the reaction solvent are preferably used.

[0029] The temperature at which the disulfide bond formation reaction is carried out is arbitrary within the range where the effects of the present invention can be obtained. The temperature at which the reaction is carried out may be, for example, 4 to 50 °C, 15 to 40 °C, 20 to 35 °C, or 25 to 30 °C. Further, when a heat-labile substrate (for example, a protein) is used as the substrate, the temperature at which the disulfide bond formation reaction is carried out may be a low temperature (for example, 4 to 10 °C).

[0030] The reaction time of the disulfide bond formation reaction can be arbitrarily set so that the reaction proceeds sufficiently. The reaction time may be, for example, 0.1 to 6 hours, 0.2 to 2 hours, or 0.5 to 1 hour. Further, when the reaction rate decreases, such as when the reaction temperature is a low temperature (for example, 4 to 10 °C), the reaction time may be, for example, 2 to 48 hours, 6 to 36 hours, or 12 to 24 hours.

[0031] In the disulfide bond formation reaction, any amount of the resin-supported cyclic tellurium compound can be used within the range where the effects of the present invention can be obtained. When the substrate is a low-molecular-weight organic compound (for example, having a molecular weight of 1000 or less), preferably 0.1 to 50 mol%, more preferably 0.2 to 10 mol%, particularly preferably 0.5 to 5 mol% of the resin-supported cyclic tellurium compound can be used relative to the molar equivalent of the thiol group possessed by the substrate. Further, when the substrate is a peptide or a protein, preferably 10 to 500 mol%, more preferably 20 to 200 mol%, particularly preferably 50 to 100 mol% of the resin-supported cyclic tellurium compound can be used relative to the molar equivalent of the thiol group possessed by the substrate.

[0032] The method for forming an intramolecular or intermolecular disulfide bond of the present disclosure may include a step of removing the solid phase by filtration or the like after the step of carrying out the disulfide bond formation reaction.

Examples

[0033] Hereinafter, the present invention will be described by way of examples, but these examples do not limit the present invention. The commercially available reagents and equipment mentioned in the examples were used in accordance with the manufacturer's instructions or established methods unless otherwise specified.

[0034] [Example 1] Preparation of Resin-Supported Cyclic Tellurium Compound Formula 7 The cyclic tellurium compound represented by TIFF2025109012000011.tif43170 was prepared by the method described in K. Arai et al., Catal. Sci. Technol., 2019, Vol. 9, pp. 3647 - 3655. According to the scheme shown in Figure 2, the cyclic tellurium compound represented by Formula 2 was supported on the commercially available resin NovaSyn™ TG carboxy resin (Merck), whereby the resin - supported cyclic tellurium compound was prepared. More specifically, in a column - type filter container for solid - phase synthesis, 2.5 μL of DMF was added to the commercially available resin NovaSyn™ TG carboxy resin (0.27 mmol / g, 27 μmol, 100 mg), and the resin was allowed to swell by standing for 1 hour or more. After removing the DMF by suction filtration, the swollen resin was washed three times with 500 μL of DMF. Suction filtration was performed by attaching the reaction vessel to a dry aspirator and reducing the pressure inside the vessel (the same applies hereinafter). 2.5 μL of DMF was added to the container containing the washed resin, and the cyclic tellurium compound represented by Formula 2 (51 μmol; 12.0 mg), (benzotriazol - 1 - yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyBoP™) (0.11 mmol, 59 mg), and N,N - diisopropylethylamine (DIPEA) (0.23 mmol, 38 μL) were dissolved therein, and this was subjected to vibration stirring in a thermostatic bath at 27°C for 19 hours, whereby a condensation reaction occurred between the amino group of the cyclic tellurium compound and the carboxy group of the resin. After completion of the reaction, the reaction solution was removed by suction filtration. The obtained resin was washed three times with 500 μL of DMF and then three times with 500 μL of methanol. By drying this under reduced pressure, a resin-supported cyclic tellurium compound was obtained.

[0035] In the obtained resin-supported cyclic tellurium compound, the amount of hydrogen peroxide required for the reduction of the cyclic tellurium compound from the telluride form to the telluroxide form was titrated with KMnO4 to determine the immobilization yield of the cyclic tellurium compound on the resin. The immobilization yield of the cyclic tellurium compound on the resin in the obtained resin-supported cyclic tellurium compound was determined to be 71%.

[0036] [Example 2] Disulfide Bond Reaction in Low-Molecular-Weight Organic Compounds Using decanethiol as a substrate, as shown in Table 1, hydrogen peroxide (H2O2) or t-butyl hydroperoxide (tBuOOH) was used as an oxidizing agent, and ethanol (EtOH), acetonitrile (CH3CN), ethyl acetate (EtOAc), toluene, chloroform (CHCl3), or dichloromethane (CH2Cl2) was used as a solvent. A disulfide bond formation reaction using the resin-supported cyclic tellurium compound as a catalyst was carried out by the method described below. The choice of whether to use H2O2 or tBuOOH as the oxidizing agent was determined from the viewpoint of solubility in the solvent. Decanethiol has one thiol group in the molecule. In this reaction, the two thiol groups in two molecules of decanethiol are converted into a disulfide bond, and a decanethiol dimer bonded by an intermolecular disulfide bond is formed.

[0037] A resin-supported cyclic tellurium compound (0.27 μmol) and 1 μL of a solvent were added to a column-type filter container for solid-phase synthesis. After swelling the resin for 1 hour or more, the solvent was removed by suction filtration, and the resin was further washed three times with 500 μL of the solvent. To this, a solvent (1 μL), decanethiol (54 μmol, 9.4 mg), and H2O2 (59 μmol, 5.2 μL) or tBuOOH (59 μmol, 8.1 μL) were added, and the disulfide bond formation reaction was carried out by shaking and stirring at 27 °C for 1 hour. The solution in which the reaction product was dissolved was recovered by suction filtration and concentrated by an evaporator. By analyzing the solution by 1H NMR, the results of determining the conversion efficiency from the thiol group to the disulfide bond and the yield of the reaction are shown in Table 1.

[0038]

Table 1

[0039] As shown in Table 1, in any case of using a solvent, by using the resin-supported cyclic tellurium compound as a catalyst, the conversion efficiency from the thiol group to the disulfide bond was improved compared to the case where no catalyst was used. Also, when ethanol, acetonitrile, ethyl acetate, chloroform, or dichloromethane was used as the solvent, the conversion efficiency from the thiol group to the disulfide bond was 100%. When toluene was used as the solvent, the conversion efficiency from the thiol group to the disulfide bond was 62%. The yield of the reaction product was good when ethanol, acetonitrile, ethyl acetate, chloroform, or dichloromethane was used as the solvent, and especially the yield was 100% when chloroform was used.

[0040] [Example 3] Reusability of Resin-Supported Cyclic Tellurium Compound To evaluate the reusability of the resin-supported cyclic tellurium compound as a catalyst, the resin-supported cyclic tellurium compound recovered after the disulfide bond formation reaction was reused as a catalyst again, and the disulfide bond formation reaction using decanethiol as a substrate was carried out in CHCl3. In the first reaction, the swollen and washed resin-supported cyclic tellurium compound was used under the same conditions as in Example 2, Entry 5. In the reactions after the second time, for the resin in the column-type filter container for solid-phase synthesis after the previous reaction, 500 μL of CHCl₃ was added, and the resin was washed by removing CHCl₃ by suction filtration, and a resin-supported cyclic tellurium compound in which this treatment was carried out 5 times was used. Other reaction conditions were the same as those in Example 2, Entry 5. The products obtained in each reaction were analyzed by ¹H NMR spectrum in the same manner as in Example 1, and the conversion efficiency from the thiol group to the disulfide bond in each reaction was determined. The results are shown in Figure 3. As shown in Figure 3, the conversion efficiency from the thiol group to the disulfide bond was maintained at 76% of the conversion efficiency in the first reaction even in the reaction using the resin-supported cyclic tellurium compound twice, 59% of the conversion efficiency in the first reaction was maintained even in the reaction using it three times, and 41% of the conversion efficiency in the first reaction was maintained even in the reaction using it four times. Also, in all four reactions, decanethiol was chemically selectively converted to a decanethiol dimer bonded by an intermolecular disulfide bond, and no by-products were detected. Also, when the resin used in the previous reaction was immersed in the solvent used in the next reaction and stored at 4 °C for 1 month in a sealed container and then reused in the next reaction, the same results as above were obtained.

[0041] [Example 4] Disulfide Bond Formation Reaction in Various Low-Molecular-Weight Organic Compounds Under the same conditions as in Example 3, the yields of the disulfide bond formation reactions catalyzed by the resin-supported cyclic tellurium compound in 14 kinds of lipophilic or water-soluble low-molecular-weight organic compounds were determined. The results are shown in Table 2. The 14 kinds of lipophilic or water-soluble low-molecular-weight organic compounds used here are compounds having one thiol group in the molecule, and by this reaction, dimer compounds bonded by intermolecular disulfide bonds were produced.

[0042]

Table 2

[0043] As shown in Table 2, in any of the 14 kinds of lipophilic or hydrophilic low-molecular-weight organic compounds, the disulfide bond formation reaction using the resin-supported cyclic tellurium compound as a catalyst showed a good yield.

[0044] [Example 5] Formation of Intramolecular Disulfide Bond in Peptides Using reduced oxytocin (CYIQNCPLG-NH2) as a substrate, H2O2 as an oxidizing agent, and 0.1% TFA / H2O or CH3CN / H2O (1:3 (v:v)) as a solvent, a disulfide bond formation reaction using the resin-supported cyclic tellurium compound as a catalyst was carried out. Reduced oxytocin is a 9-amino acid residue peptide and has side chain thiol groups at the cysteine residues at positions 1 and 6. By performing a disulfide bond formation reaction in reduced oxytocin, one disulfide bond is formed from two thiol groups, and oxidized oxytocin is formed.

[0045] 100 nmol of reduced oxytocin was dissolved in 500 μL of 0.1% TFA / H2O or CH3CN / H2O (1:3 (v:v)) in a 1.5 μL volume tube. To the solution, a resin-supported cyclic tellurium compound (0.1 μmol / μL) swollen with 100 - 210 nmol equivalent of ultrapure water was added, and 0.1% TFA / H2O or CH3CN / H2O (1:3 (v:v)) was used to adjust the total volume of the reaction solution to 900 μL. An aqueous solution (22.8 mM) containing 100 - 150 nmol of H2O2 was added to this solution, and a disulfide bond formation reaction was carried out by performing shaking and stirring in a constant temperature bath at 27°C. After the reaction, 10 μL of the reaction solution was sampled, and 200 μL of an aqueous solution of 2-Aminomethane thiosulfonate (AEMTS) (7 mg / 1 μL / H2O) was added thereto, followed by stirring at room temperature for 5 minutes to block unreacted thiol groups. The solution to which 830 μL of 0.1% TFA / H2O was added was analyzed by reversed-phase high-performance liquid chromatography (RP-HPLC) to analyze the progress of the reaction. An example of the RP-HPLC chromatogram is shown in Figure 4. The peak of oxidized oxytocin (theoretical molecular weight 1008.5) was identified by analyzing the sample collected from the peak by MALDI-TOF-MS. The results of MALDI-TOF-MS are shown in Figure 5. The abundances of reduced oxytocin, oxidized oxytocin, and by-products determined from the ratio of the peak areas of the chromatogram after the reaction are shown in Table 3.

[0046]

Table 3

[0047] As shown in Table 3, by using the resin-supported cyclic tellurium compound as a catalyst, the disulfide bond formation reaction in the peptide was promoted. Also, the reaction proceeded sufficiently in a short time, and the amount of by-products formed was small.

[0048] [Example 6] Formation of Two Intramolecular Disulfide Bonds in Peptides A disulfide bond formation reaction was carried out using reduced human relaxin A (QLYSALANKC CHVGCTKRSL ARFC) as a substrate, H2O2 as an oxidizing agent, and 0.1% TFA / H2O as a solvent, with a resin-supported cyclic tellurium compound as a catalyst. Reduced human relaxin A is a peptide of 24 amino acid residues, and cysteine residues are at positions 10, 11, 15, and 24, each having a thiol group in the side chain. By carrying out a disulfide bond formation reaction in reduced human relaxin A, two intramolecular disulfide bonds are formed from four thiol groups, and oxidized human relaxin A is formed.

[0049] Except for using 80 nmol of reduced human relaxin A, 160 nmol equivalent of resin-supported cyclic tellurium compound, and 320 nmol of H2O2, the disulfide bond formation reaction was carried out under the same conditions as in Example 5, and the product was analyzed by RP-HPLC (Figure 6) and MALDI-TOF-MS (Figure 7). As shown in Figure 7, it was confirmed that the human relaxin A after the reaction had the molecular weight of oxidized human relaxin A having two intramolecular disulfide bonds (theoretical molecular weight 2668.3). In addition, when a thiol group blocking reagent (2-Aminoethyl methanethiosulfonate) that reacts with the unreacted thiol group was added to the human relaxin A after the reaction, no change was observed in the peak pattern of RP-HPLC. Therefore, it was confirmed that oxidized human relaxin A having two intramolecular disulfide bonds was formed from this reaction.

[0050] [Example 7] Formation of Three Intramolecular Disulfide Bonds in Peptides A disulfide bond formation reaction using reduced hirudin CX397 (VVYTDCTESG QNLCLCEGSN VCGQGNKCIL GSDGEKNQCV TGEGTPKPQS HNQGDFEPIP EDAYDE) as a substrate, H2O2 as an oxidizing agent, and 0.1% TFA / H2O as a solvent, with a resin-supported cyclic tellurium compound as a catalyst, was carried out. Reduced hirudin CX397 is a peptide of 66 amino acid residues, and cysteine residues are at positions 6, 14, 16, 22, 28, and 39, each having a thiol group in the side chain. By carrying out a disulfide bond formation reaction in reduced human relaxin A, three intramolecular disulfide bonds are formed from six thiol groups, and oxidized hirudin CX397 is formed.

[0051] The disulfide bond formation reaction was carried out under the same conditions as in Example 5, except that 80 nmol of reduced hirudin CX397, 240 nmol equivalent of resin-supported cyclic tellurium compound, and 320 nmol of H2O2 were used, and the product was analyzed by RP-HPLC (Figure 8) and MALDI-TOF-MS (Figure 9). As shown in Figure 9, it was confirmed that the hirudin CX397 after the reaction had the molecular weight of oxidized hirudin CX397 having three intramolecular disulfide bonds (theoretical molecular weight 7007.00). Further, when a thiol group blocking reagent (2-Aminoethyl methanethiosulfonate) that reacts with the unreacted thiol group was added to the hirudin CX397 after the reaction, no change was observed in the peak pattern of RP-HPLC. Therefore, it was confirmed that oxidized hirudin CX397 having three intramolecular disulfide bonds was formed from this reaction.

[0052] A non-limiting list of exemplary embodiments of the present disclosure and combinations thereof is disclosed below. [1] Formula 1: TIFF2025109012000015.tif43170 [In Formula 1, L is a linker and X is a resin moiety] a structure represented by, or Formula 2: TIFF2025109012000016.tif35170 [In Formula 2, L is a linker and X is a resin moiety] a structure represented by A resin-supported cyclic tellurium compound having [2] Formula 3: TIFF2025109012000017.tif42170 [In Formula 3, L is a linker and X is a resin moiety] The resin-supported cyclic tellurium compound according to [1] or [2], having a structure represented by [3] The resin-supported cyclic tellurium compound according to [1], wherein the linker is -NHCO-, -CONH-, -OCO-, or -COO-. [4] The resin-supported cyclic tellurium compound according to any one of [1] to [3], wherein the resin portion is a resin portion containing polystyrene resin. [5] A method for forming at least one intramolecular disulfide bond in a compound containing at least one pair of thiol groups, comprising forming at least one intramolecular disulfide bond by oxidizing at least one pair of thiol groups with an oxidizing agent using the resin-supported cyclic tellurium compound according to any one of [1] to [4] as a catalyst. [6] The method according to [5], wherein the oxidizing agent is ROOH [R is hydrogen or a C1-C6 alkyl group], meta-chloroperbenzoic acid, or urea hydrogen peroxide. [7] The method according to [5] or [6], wherein the compound containing at least one pair of thiol groups is a protein or a peptide. [8] A method for producing a compound having at least one intramolecular disulfide bond, comprising forming at least one intramolecular disulfide bond by the method according to any one of [5] to [7]. [9] A method for forming an intermolecular disulfide bond between a first compound containing at least one thiol group and a second compound containing at least one thiol group, comprising forming at least one intermolecular disulfide bond by oxidizing at least one thiol group contained in the first compound and at least one thiol group contained in the second compound with an oxidizing agent using the resin-supported cyclic tellurium compound according to any one of [1] to [4] as a catalyst.

[10] The method according to [9], wherein the oxidizing agent is ROOH [R is hydrogen or a C1-C6 alkyl group], meta-chloroperbenzoic acid, or urea hydrogen peroxide.

[11] The method according to [9] or

[10] , wherein at least one of the first compound and the second compound is a protein or a peptide.

[12] The method according to any one of [9] to

[11] , wherein the first compound and the second compound are the same compound.

[13] The method according to any one of [9] to

[11] , wherein the first compound and the second compound are different compounds.

[14] A method for producing a third compound in which a first compound and a second compound are bonded by at least one intermolecular disulfide bond, comprising forming at least one intermolecular disulfide bond between the first compound and the second compound by the method according to any one of [9] to

[13] .

Claims

1. Formula 1: [In Formula 1, L is a linker and X is a resin moiety] A structure represented by, or Formula 2: [In Formula 2, L is a linker and X is a resin moiety] A structure represented by A resin-supported cyclic tellurium compound having.

2. Formula 3: [In Formula 3, L is a linker and X is a resin moiety] The resin-supported cyclic tellurium compound according to Claim 1, having a structure represented by.

3. The resin-supported cyclic tellurium compound according to Claim 1, wherein the linker is -NHCO-, -CONH-, -OCO-, or -COO-.

4. The resin-supported cyclic tellurium compound according to Claim 1, wherein the resin moiety is a resin moiety containing a polystyrene resin.

5. A method for forming at least one intramolecular disulfide bond in a compound containing at least one pair of thiol groups, comprising oxidizing at least one pair of thiol groups with an oxidizing agent using the resin-supported cyclic tellurium compound according to any one of Claims 1 to 4 as a catalyst to form at least one intramolecular disulfide bond.

6. The method according to Claim 5, wherein the oxidizing agent is ROOH [R is hydrogen or a C1-C6 alkyl group], meta-chloroperbenzoic acid, or urea hydrogen peroxide.

7. The method according to Claim 5, wherein the compound containing at least one pair of thiol groups is a protein or a peptide.

8. A method for producing a compound having at least one intramolecular disulfide bond, comprising forming at least one intramolecular disulfide bond by the method according to Claim 5.

9. A method for forming an intermolecular disulfide bond between a first compound containing at least one thiol group and a second compound containing at least one thiol group, comprising oxidizing at least one thiol group contained in the first compound and at least one thiol group contained in the second compound with an oxidizing agent using the resin-supported cyclic tellurium compound according to any one of Claims 1 to 4 as a catalyst to form at least one intermolecular disulfide bond.

10. The method according to Claim 9, wherein the oxidizing agent is ROOH [R is hydrogen or a C1-C6 alkyl group], meta-chloroperbenzoic acid, or urea hydrogen peroxide.

11. The method according to claim 9, wherein at least one of the first compound and the second compound is a protein or a peptide. **Claim 12** The method according to claim 9, wherein the first compound and the second compound are the same compound. **Claim 13** The method according to claim 9, wherein the first compound and the second compound are different compounds. **Claim 14** A method for producing a third compound in which a first compound and a second compound are linked by at least one intermolecular disulfide bond, the method comprising forming at least one intermolecular disulfide bond between the first compound and the second compound by the method according to claim 9.

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