JP2013035775A - Cleavage method of methyl ether bond in organic compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleavage method of a methyl ether bond in an organic compound for cleaving the methyl ether bond in the organic compound which is usable as various synthesis methods for organic compounds without especially using a solvent or a post-treatment agent.SOLUTION: The method is characterized in that an organic compound having a methyl ether bond is contacted with hydrogen iodide gas at room temperature without dissolving a solvent so that the methyl ether bond is cleaved.

Description

  The present invention relates to a method for cleaving a methyl ether bond in an organic compound for cleaving the methyl ether bond in an organic compound applied to, for example, pharmaceuticals, dye materials, liquid crystal materials, polarizing films and the like.

  A methyl ether group is widely used as a protecting group for a hydroxy group. In particular, the cleavage reaction for cleaving the bond between carbon and oxygen constituting the methyl ether group can be said to be a very important reaction in the synthesis of various organic compounds.

As a conventional cleavage reaction of a methyl ether group, as shown in the following [Chemical Formula 1], a reaction using boron tribromide (BBr ₃ ) (see Non-Patent Document 1), or as shown in [Chemical Formula 2]. In addition, a reaction using trimethylsilane iodide ((CH ₃ ) ₃ SiI) (see Non-Patent Document 2), and a reaction using a sodium salt of thiol or sodium metal as shown in [Chemical Formula 3] (See Non-Patent Document 3).

  In addition to this, for example, as shown in [Chemical Formula 4], a conventional technique of a cleavage reaction using a hydrogen iodide aqueous solution (hydroiodic acid) has also been proposed (see Non-Patent Document 4).

  Incidentally, the technical idea of using hydroiodic acid as a dealkylating agent is also shown in Patent Document 1, and synthesis of hexahydroxytriphenylene useful as a liquid crystal intermediate as shown in [Chemical Formula 5] below. As a method, a technique using an aqueous hydrogen iodide solution has been proposed.

  In particular, dihydroxybenzene derivatives obtained by cleaving the methyl ether bond of dimethoxybenzene derivatives are used as various highly useful compounds. For example, resorcinol derivatives are those whose structures are applied to fungicides and the like, and catechol derivatives are used as dye coloring agents. Hydroquinone derivatives are used as polymerization inhibitors and reducing agents. It can be said that the cleavage reaction of a methyl ether bond is an indispensable technique for chemically modifying these compounds.

Japanese Patent Laid-Open No. 8-119894 Japanese Patent Laid-Open No. 9-20709

Tetrahedron, 24, 2289 (1968) The Journal of Organic Chemistry, 42, 3761 (1977) Tetrahedron, 38, 3687 (1982) European Journal of Organic Chemistry, p. 359 (1992)

As described above, various methods have been proposed for the methyl ether cleavage reaction, but each of these reactions requires a solvent and a post-treatment. In the disclosed technology of Non-Patent Document 1, boron tribromide (BBr ₃ ) is unstable with respect to water, and therefore requires an organic solvent, and it is also necessary to perform a post-treatment by adding water after the reaction. Further, in the disclosed technique of Non-Patent Document 2, a solvent is required even in a reaction using iodinated trimethylsilane ((CH ₃ ) ₃ SiI), and it is necessary to decompose iodinated trimethylsilane by adding methanol. Moreover, in the disclosed technique of Non-Patent Document 3, the sodium salt of thiol and sodium metal are unstable with respect to water, and post-treatment with water is required after the reaction. That is, in the disclosed technique of Non-Patent Document 3, it is necessary to add water and a solvent to the reaction tank, and it is necessary to perform an extraction process and a concentration process for that purpose.

  In the cleavage method using an aqueous hydrogen iodide solution, it is generally unnecessary to add another solvent during the reaction. However, in the disclosed technique of Non-Patent Document 4, purification by extraction and column chromatography is performed. . That is, according to the conventional method, it is necessary to use an organic solvent or a post-treatment agent in the reaction or the post-treatment, and there is a problem regarding the treatment effort of the used organic solvent or the post-treatment agent. Further, as a method not using these organic solvents and post-treatment agents, according to the disclosed technology of Patent Document 1, it can be applied to a crystallized compound, but it cannot be a solution for a compound that does not crystallize. Furthermore, in the reaction using the hydrogen iodide aqueous solution in the techniques disclosed in Non-Patent Document 4 and Patent Document 1, heating to a high temperature is also required.

  Thus, in the conventional method, in addition to the problems related to the solvent and the post-treatment agent used in the reaction, there are problems related to workability due to the labor burden related to separation and purification or the necessity of decomposition of the raw material by high temperature reaction. It was.

  In addition, as a technique that does not use a solvent in a cleavage method using hydroiodic acid, for example, a method disclosed in Patent Document 2 is also disclosed. However, in the technique disclosed in Patent Document 2, no special study has been made on a compound having a plurality of ether bonds. For this reason, establishment of the method of cleaving a plurality of methyl ethers at once is desired.

  That is, the present situation is that no solvent or post-treatment agent is required, and the cleavage of a plurality of methyl ether bonds or the selective cleavage of different alkyl ether bonds has not been achieved.

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is, in particular, in a method for cleaving a methyl ether bond in an organic compound for cleaving a methyl ether bond in an organic compound. An object of the present invention is to provide a method for cleaving a methyl ether bond that can be used as a method for synthesizing various organic compounds without using a solvent or a post-treatment agent.

  In order to solve the above-described problems, the present inventor has made an organic compound containing a methyl ether bond contact with hydrogen iodide gas at room temperature without dissolving it in a solvent, thereby cleaving the methyl ether bond. Thus, the present inventors have invented a method for cleaving a methyl ether bond that can cleave a plurality of methyl ether bonds at once without using a solvent or a post-treatment agent.

  That is, in the method for cleaving a methyl ether bond according to claim 1, the methyl ether bond is cleaved by contacting an organic compound containing the methyl ether bond with hydrogen iodide gas at room temperature without dissolving it in a solvent. It is characterized by making it.

  The method for cleaving a methyl ether bond according to claim 2 comprises contacting an organic compound containing a methyl ether bond and a bond of another functional group with hydrogen iodide gas at room temperature without dissolving it in a solvent. Only the methyl ether bond is selectively cleaved.

  The method for cleaving a methyl ether bond according to claim 3 is the method according to claim 1 or 2, wherein after the reaction is completed by contacting with the hydrogen iodide gas, a hydroxy group is formed after the methyl ether bond is cleaved. A product after cleavage is obtained without using a necessary post-treatment agent.

  According to the present invention having the above-described configuration, a post-treatment agent such as a solvent or water, which is required when boron tribromide or trimethylsilyl iodide is used, is not necessary. For this reason, according to this invention, reduction of a waste is promoted more. Moreover, since it can be made to react at room temperature (20 degreeC-35 degreeC), even if it is a heat unstable organic compound which becomes a problem by reaction using hydrogen iodide aqueous solution, workability | operativity accompanying the manufacture Can be improved. In addition, simple reactions and post-treatment methods can be provided for various products. Furthermore, a plurality of methyl ethers can be cleaved at once, and selective cleavage of different alkyl ether bonds can be achieved, which can be used as a method for synthesizing various organic compounds.

It is a figure which shows the experimental system for implement | achieving the cleavage method of the methyl ether bond in the organic compound to which this invention is applied. It is a figure which shows the reaction system for implement | achieving the cleavage method of the methyl ether bond in the organic compound to which this invention is applied.

  Hereinafter, embodiments of the present invention will be described in detail.

  The method for cleaving a methyl ether bond to which the present invention is applied involves cleaving a methyl ether bond in an organic compound without dissolving it in a solvent.

  The following [Chemical Formula 6] shows a general formula of a starting material used in a method for cleaving a methyl ether bond to which the present invention is applied.

In this general formula, R ^{1 to} R ⁵ in the starting material are each independently a hydrogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon, a substituted or unsubstituted monovalent aromatic ring group, an ether group, a carbonyl Indicates a group. Further, in this starting material, at least one or more methyl ether groups (—OCH ₃ ) are bonded in addition to R ^{1 to} R ⁵ . Incidentally, when two or more methyl ether groups are bonded, one or more of these R ^{1 to} R ⁵ are methyl ether groups.

  In the present invention, an organic compound serving as a starting material as described above to which at least one methyl ether bond is bonded is caused to undergo a cleavage reaction in the absence of a solvent as described later, whereby a methyl group in the methyl ether bond is obtained. Is changed to a hydroxy group in which a hydrogen atom is bonded to an oxygen atom.

  The following [Chemical Formula 7] and [Chemical Formula 8] formulas are general formulas for a method for cleaving a methyl ether bond in an organic compound to which the present invention is applied.

  The reaction of the formula [7] is an example in which an organic compound having two methyl ether bonds is used as a starting material, and this is subjected to a cleavage reaction by contacting with hydrogen iodide gas at room temperature. [Chemical Formula 8] is an example in which an organic compound having a methyl ether group and an ethyl ether group is subjected to a cleavage reaction by contacting with hydrogen iodide gas at room temperature. [Chemical 9] is an example in which a compound having a methyl ether group and a carbonyl group is subjected to a cleavage reaction by contacting with hydrogen iodide gas at room temperature.

  [Chemical Formula 7] shows that only one of the methyl ether bonds can be cleaved, but each of the two methyl ether bonds can be cleaved into a hydroxy group. Yes. [Chemical Formula 8] shows that only the methyl ether group is selectively cleaved, and the cleavage to another functional group, the ethyl ether group, does not progress much. [Chemical 9] shows that when a carbonyl group is substituted in addition to methyl ether, only the cleavage of the methyl ether bond proceeds.

  In these cleavage methods, an organic compound (starting material) containing a methyl ether bond is brought into contact with hydrogen iodide gas at room temperature without dissolving it in a solvent. The room temperature here means about 20 ° C. to 35 ° C., but is not strictly limited to this temperature range. If the room temperature at the time of the cleavage reaction is less than 20 ° C., the intended cleavage reaction described below does not proceed. On the other hand, when the room temperature during the cleavage reaction exceeds 35 ° C., the reaction itself proceeds, but the stability of the resulting compound decreases. For this reason, it is desirable that the room temperature is about 20 ° C to 35 ° C.

  That is, by using hydrogen iodide gas, a by-product is removed under reduced pressure after the reaction without using a solvent or a post-treatment agent, thereby obtaining an organic compound after cleavage.

  Actually, only the starting material is charged in a nitrogen atmosphere, and after removing the nitrogen, further contacting with hydrogen iodide gas, the cleavage reaction of methyl ether in the starting material at room temperature (about 25 ° C.). Let Then, after the cleavage reaction, the hydrogen iodide gas remaining as a by-product and methyl iodide as a by-product are removed by a diaphragm pump. This makes it possible to obtain the target compound in which the methyl ether bond is substituted with a hydroxy group.

  According to the present invention having the above-described configuration, the post-treatment by adding a solvent, water, or the like, which is necessary when boron tribromide or trimethylsilane iodide is used, becomes unnecessary. It becomes possible to reduce. Further, any of the above-described cleavage reactions can be achieved at room temperature. For this reason, even if the starting material is an organic compound that becomes unstable at high temperatures, it can be easily reacted with hydroiodic acid. Furthermore, even when the organic compound contains other functional groups in addition to the methyl ether group, the cleavage reaction can proceed selectively only to the methyl ether group, and it can be applied to the synthesis of various organic compounds. Is also possible.

  Next, examples for actually carrying out the method for cleaving a methyl ether bond in an organic compound to which the present invention is applied will be described. Examples 1 to 7 to be described later have been experimentally verified using the experimental system 1 shown in FIG. First, the experimental system 1 will be described.

  In this experimental system 1, a nitrogen cylinder 11, a hydrogen iodide cylinder 12, a branch pipe 13 that forms a merging path from the nitrogen cylinder 11 and the hydrogen iodide cylinder 12, and the flow rate of the gas that has passed through the branch pipe A flow meter 14 for measuring the flow rate, a pump 15 exchangeable with the branch pipe 13, a branch pipe 20 connected to the flow meter 14, and a rubber plug 21 provided at the tip of the branch pipe 20a of the branch pipe 20 It has.

  Further, the experimental system 1 includes a backflow prevention container 16 connected to the other end of the branch pipe 20 and a neutralization container 17 connected to the backflow prevention container 16.

  The nitrogen cylinder 11 is a cylinder filled with nitrogen gas for actually cleaning the inside of the reaction vessel, and is configured to be able to send the filled nitrogen gas by opening the valve 11a. The nitrogen cylinder 11 is usually provided with a flow meter 11b for measuring the outflow amount of nitrogen.

  The hydrogen iodide cylinder 12 is filled with hydrogen iodide gas necessary for performing the cleavage method to which the present invention is applied. Similarly, the hydrogen iodide cylinder 12 can control the outflow and stop of the internal gas by opening and closing the valve 12a.

  The branch tube 13 is connected to the nitrogen cylinder 11 and the hydrogen iodide cylinder 12, and introduces nitrogen gas or hydrogen iodide gas supplied from the cylinders 11 and 12 to the flow meter 14. The flow meter 14 measures the flow rate of each gas sent from the branch tube 13 and displays it so that the operator can visually recognize it.

  The backflow prevention container 16 is composed of, for example, an air collection bottle or the like, and each gas that has passed through the branching unit 20 is supplied. The gas collected in the backflow prevention container is sent to the neutralization container 17. The neutralization container 17 is filled with an aqueous NaOH solution up to about half of the container in advance. The gas sent from the backflow prevention container 16 always comes into contact with the aqueous NaOH solution in the neutralization container 17, so that the acidic gas is neutralized by alkali with NaOH. The gas neutralized with NaOH is discharged from the neutralization container 17.

  The pump 15 is replaceable with the branch pipe 13 and is used when decompressing each container. This pump 15 can also be used when depressurizing the inside of the flask described later. The pump 15 may be embodied by a diaphragm pump or the like, for example.

  The syringe syringe 22 is fixed by the tip of the needle 22b penetrating the rubber stopper 21 and protruding into the branch tube 20. The syringe syringe 22 is configured to be able to suck gas into the injection tube by pulling the piston 22a. As described above, the tip of the needle 22b protrudes into the branch tube 20 and the piston 22a is pulled, whereby the gas flowing in the branch tube 20 can be accommodated in the injection tube.

  FIG. 2 (a) shows an example of a reaction system 2 for actually cleaving an organic compound containing a methyl ether bond. In this reaction system 2, a flask 25 for carrying out a cleavage reaction by introducing a starting material 26, a rubber stopper 27 inserted into the opening of the flask 25, and one end of the flask 25 through the rubber stopper 27. And a two-way cock 24 protruding inward.

  The flask 25 may be any type of flask such as an Erlenmeyer flask, a round bottom flask, or an eggplant flask, but it is desirable to use an eggplant flask. Further, the two-way cock 24 can open the inside of the flask 25 to the outside air when the knob is opened, and can seal the inside of the flask 25 with the outside when the knob is closed. Is possible.

  Next, the case where the cleavage method to which the present invention is actually applied using such experimental system 1 and reaction system 2 will be described.

  First, in the reaction system 2, a starting material made of an organic compound containing a methyl ether bond is charged into the flask 25. Next, the opening of the flask 25 is closed with a rubber stopper 27, and the two-way cock 24 is attached through this. And the inside of this flask 25 is pressure-reduced using the pump 15, and the starting material 26 is dried by leaving still for a while. Next, nitrogen is injected into the flask 25 to return to atmospheric pressure.

  Actually, when nitrogen is injected into the flask 25, a rubber balloon filled with nitrogen is attached to one end of the two-way cock 24, and the knob of the two-way cock 24 is opened, so that the nitrogen gas in the rubber balloon is removed from the flask. 25 will be introduced. Next, the pressure in the flask 25 is reduced again using the pump 15. In the process of depressurization, the knob of the two-way cock 24 is opened as shown in FIG.

  Next, hydrogen iodide gas is injected into the flask 25. In such a case, in the experimental system 1, the inside of the injection tube is drawn by pulling the piston 22a of the syringe syringe 22 with the tip of the needle 22b protruding through the rubber stopper 21 while flowing hydrogen iodide gas from the hydrogen iodide cylinder 12. Fill with hydrogen iodide gas. Next, as shown in FIG. 2A, the rubber stopper 21 is attached to one end of the two-way cock 24, the knob of the two-way cock 24 is opened, and the piston 22a is pushed in. Thereby, hydrogen iodide gas in the injection tube is introduced into the flask 25.

  Next, nitrogen gas is further introduced into the flask 25 filled with the hydrogen iodide gas to return the inside of the flask 25 to atmospheric pressure. Incidentally, since the method of introducing nitrogen gas into the flask 25 is the same as the above-described process, the description thereof is omitted here. After the inside of the flask 25 is returned to atmospheric pressure by this nitrogen filling, the knob of the two-way cock 24 is closed and sealed as shown in FIG. 2 (b), and the flask is left to stand at room temperature (about 25 ° C.) for about 24 hours. . In this process, the cleavage reaction proceeds. Thereafter, the inside of the flask 25 is decompressed again using the pump 15.

  By performing the process as described above, an organic compound containing a methyl ether bond can be cleaved by contacting it with hydrogen iodide gas at room temperature without dissolving it in a solvent. Become.

  According to the present invention having the above-described configuration, water, hydrochloric acid, sulfuric acid, nitric acid required for forming a hydroxy group after cleavage of a methyl ether bond, which is required when boron tribromide or trimethylsilyl iodide is used, is used. , Protonic acids such as phosphoric acid, or alcohols such as methanol, ethanol, 2-propanol, phenol, acetic acid, propionic acid, butyric acid, valeric acid, benzoic acid and organic compounds having a hydroxy group or carboxylic acid such as carboxylic acid, Selected from the group consisting of diethyl ether, diisopropyl ether, tetrahydrofuran, ethyl acetate, methyl ethyl ketone, benzene, toluene, chloroform, methylene chloride, and other ether-based, ester-based, ketone-based, aromatic hydrocarbon, and halogenated hydrocarbon-based organic solvents. Extractable organic containing at least one Post-treatment agent that was including the medium or the like is unnecessary. For this reason, according to this invention, reduction of a waste is promoted more. Moreover, since it can be made to react at room temperature vicinity, even if it is a heat unstable organic compound which becomes a problem by reaction using hydrogen iodide aqueous solution, the workability | operativity accompanying the manufacture can be improved. In addition, simple reactions and post-treatment methods can be provided for various products. Furthermore, when a plurality of methyl ether bonds can be cleaved at once, or when a functional group other than the methyl ether bond exists, only the methyl ether bond is selectively changed without changing the functional group other than the methyl ether bond. It can also be cleaved into various organic compounds and can be used as a method for synthesizing various organic compounds.

Synthesis of catechol (o-dihydroxybenzene)

Attach a two-way cock with a septum at the tip to an eggplant flask containing o-dimethoxybenzene (144 mg, 1.04 mmol), and let stand overnight under reduced pressure in the presence of diphosphorus pentoxide to dry it. At atmospheric pressure. After reducing the pressure again with a diaphragm pump, hydrogen iodide gas (512 mg, 4.00 mmol) was introduced from the septum using a 50 mL syringe, returned to atmospheric pressure by filling with nitrogen, and allowed to stand at 25 ° C for 24 hours. I put it. After the reaction, the pressure was reduced with a diaphragm pump to obtain catechol (o-dihydroxybenzene) (109.9 mg). The yield was determined to be 96% from the integral ratio of ¹ H-NMR using tetra-n-butylammonium bromide as an internal standard.

Synthesis of resorcinol (m-dihydroxybenzene)

  Attach a two-way cock with a septum at the tip to an eggplant flask containing m-dimethoxybenzene (142 mg, 1.03 mmol), and let stand overnight under reduced pressure in the presence of diphosphorus pentoxide to dry it. At atmospheric pressure. After reducing the pressure again with a diaphragm pump, hydrogen iodide gas (509 mg, 3.97 mmol) was introduced from the septum using a 50 mL syringe, and the pressure was returned to atmospheric pressure by filling with nitrogen. I put it. After the reaction, the mixture was reduced in pressure using a diaphragm pump to obtain a mixture (112.6 mg) of resorcinol (m-dihydroxybenzene), m-methoxyphenol and m-dimethoxybenzene.

The yield is 85%: 12%: 3% of resorcinol (m-dihydroxybenzene): m-methoxyphenol: m-dimethoxybenzene, based on the integration ratio of ¹ H-NMR with tetra-n-butylammonium bromide as an internal standard. Were determined.

Synthesis of hydroquinone (p-dihydroxybenzene)

Attach a two-way cock with a septum to the tip of a eggplant flask containing p-dimethoxybenzene (141 mg, 1.02 mmol) and let it stand overnight under reduced pressure in the presence of diphosphorus pentoxide to dry it. At atmospheric pressure. After reducing the pressure again with a diaphragm pump, hydrogen iodide gas (500 mg, 3.90 mmol) was introduced from the septum using a 50 mL syringe, and the pressure was returned to atmospheric pressure by filling with nitrogen. I put it. After the reaction, the mixture was depressurized with a diaphragm pump to obtain a mixture (112.9 mg) of hydroquinone (p-dihydroxybenzene) and p-methoxyphenol. The yield was determined to be 96%: 4% of hydroquinone (p-dihydroxybenzene): p-methoxyphenol from the integral ratio of ¹ H-NMR using tetra-n-butylammonium bromide as an internal standard.

Synthesis of o-ethoxyphenol

To the eggplant flask containing o-ethoxymethoxybenzene (150 mg, 0.98 mmol), attach a two-way cock with a septum at the tip, and let it stand overnight under reduced pressure in the presence of diphosphorus pentoxide to dry it. The pressure was returned to atmospheric pressure with nitrogen. After reducing the pressure again with a diaphragm pump, hydrogen iodide gas (127 mg, 0.99 mmol) was introduced from the septum using a 50 mL syringe, and the pressure was returned to atmospheric pressure by filling with nitrogen. I put it. After the reaction, the mixture was reduced in pressure with a diaphragm pump to obtain a mixture (139.0 mg) of o-ethoxyphenol, o-methoxyphenol and o-ethoxymethoxybenzene. The yield was determined as 77%: 9%: 14% of o-ethoxyphenol: o-methoxyphenol: o-ethoxymethoxybenzene from the integral ratio of ¹ H-NMR with phenanthrene as an internal standard.

Synthesis of o-hydroxyacetophenone

A two-way cock with a septum at the tip is attached to an eggplant flask containing o-methoxyacetophenone (159 mg, 1.05 mmol), and left to stand overnight under reduced pressure in the presence of diphosphorus pentoxide. At atmospheric pressure. After reducing the pressure again with a diaphragm pump, hydrogen iodide gas (257 mg, 2.01 mmol) was introduced from the septum using a 50 mL syringe, and the pressure was returned to atmospheric pressure by filling with nitrogen. I put it. After the reaction, the mixture was reduced in pressure with a diaphragm pump to obtain a mixture (128.6 mg) of o-hydroxyacetophenone and o-methoxyacetophenone. The yield was determined to be 89%: 1% of o-hydroxyacetophenone: o-methoxyacetophenone from the integral ratio of ¹ H-NMR using phenanthrene as an internal standard.

Synthesis of p-hydroxyphenylacetic acid

To a eggplant flask containing p-methoxyphenylacetic acid (166 mg, 1.00 mmol), attach a two-way cock with a septum at the tip, and let it stand overnight under reduced pressure in the presence of diphosphorus pentoxide to dry it. The pressure was returned to atmospheric pressure with nitrogen. After reducing the pressure again with a diaphragm pump, hydrogen iodide gas (243 mg, 1.89 mmol) was introduced from the septum using a 50 mL syringe, and the pressure was returned to atmospheric pressure by filling with nitrogen. I put it. After the reaction, the mixture was reduced in pressure with a diaphragm pump to obtain a mixture (142.9 mg) of p-hydroxyphenylacetic acid and p-methoxyphenylacetic acid. The yield was determined to be 36%: 53% of p-hydroxyphenylacetic acid: p-methoxyphenylacetic acid from the integral ratio of ¹ H-NMR using tetra-n-butylammonium bromide as an internal standard.

Synthesis of o-ethoxyphenol

The test tube with screw cap mouth containing o-ethoxymethoxybenzene (150 mg, 0.98 mmol) was dried by standing overnight under reduced pressure in the presence of diphosphorus pentoxide, and returned to atmospheric pressure with nitrogen. . A 55 wt% aqueous solution of hydrogen iodide (235 mg, 1.01 mmol) was introduced using a 1 mL syringe, and the mixture was allowed to stand for 48 hours under heating and reflux. After the reaction, the mixture was left to stand for 2 days under reduced pressure in the presence of diphosphorus pentoxide to obtain a mixture (199 mg) of o-ethoxyphenol, o-methoxyphenol, and o-ethoxymethoxybenzene. The yield was determined as 63%: 13%: 20% of o-ethoxyphenol: o-methoxyphenol: o-ethoxymethoxybenzene from the integral ratio of ¹ H-NMR using phenanthrene as an internal standard.

DESCRIPTION OF SYMBOLS 1 Experimental system 2 Reaction system 11 Nitrogen cylinder 12 Hydrogen iodide cylinder 13 Branch pipe 14 Flow meter 15 Pump 16 Backflow prevention container 17 Neutralization container 20 Branch pipe 21 Rubber stopper 22 Syringe for syringe 24 Two-way cock 25 Flask 26 Start Substance 27 Rubber stopper

Claims (3)

  Cleavage of a methyl ether bond in an organic compound characterized by cleaving the methyl ether bond by contacting the organic compound containing the methyl ether bond with hydrogen iodide gas at room temperature without dissolving it in a solvent Method.   By contacting an organic compound containing a methyl ether bond and a bond of another functional group with hydrogen iodide gas at room temperature without dissolving it in a solvent, only the methyl ether bond is selectively cleaved. A method for cleaving methyl ether bonds in organic compounds.   After completion of the reaction by contacting with the hydrogen iodide gas, a product after cleavage is obtained without using a post-treatment agent necessary for hydroxy group formation after cleavage of the methyl ether bond. Item 3. A method for cleaving a methyl ether bond in an organic compound according to Item 1 or 2.

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