JPS6113694B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a method for producing ortho-methallyloxyphenol using catechol and methallyl chloride as raw materials. Ortho-methallyloxyphenol is a compound known as a raw material for carbofuran insecticides,
It is known that 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran, which is a raw material for agricultural chemicals, is produced by rearrangement and cyclization reactions of this product. Various methods for producing ortho-methallyloxyphenol (hereinafter referred to as monoether) using catechol and methallyl chloride as raw materials have been developed, but these conventional methods have a low yield of the desired monoether. The yield is low, or even if the yield is high, there are many by-products of ortho-dimethallyloxybenzene (hereinafter referred to as diether), oxidation of catechol, or formation of polymers such as dimers.
Economically disadvantageous. That is, etherification of monohydroxybenzene such as phenol is usually easily carried out in good yield without any particular difficulty. However, in the etherification of dihydroxybenzene such as catechol, both of the two hydroxy groups can participate in the etherification, so selective etherification of only one hydroxy group is extremely difficult. Furthermore, when the etherification reagent is relatively unreactive such as an alkyl derivative, the alkylation reaction to the benzene nucleus is small, but allyl derivatives, especially methallyl chloride, which are more reactive than alkyl derivatives, are used as the etherification agent. In some cases, an alkylation reaction of the benzene nucleus occurs, and control of this reaction is extremely difficult. Therefore, the formation of diethers and aromatic alkylated derivatives leads to a decrease in the yield of monoethers and the formation of mixed products, and it is difficult and economically disadvantageous to separate and produce monoethers from this mixture. The conventional technology for producing the monoether of the present invention from catechol and methallyl chloride is as follows. (1) Japanese Patent Publication No. 42-12263 (U.S. Patent No. 3474171) This is the most basic technique, in which catechol and methallyl chloride are mixed in dry acetone in the presence of equimolar amounts of K ₂ CO ₃ and KI. was reacted under reflux for 30 hours to obtain ortho-methallyloxyphenol, but the amount of acetone used,
The amount of base and catalyst used was not considered at all, and the yield was as low as 45%, suggesting whether it is possible to suppress the formation of diether and obtain the desired monoether in high yield. There's nothing to do. (2) JP-A-50-95230 (U.S. Pat. No. 3,927,118) This method describes the selective monoetherification of dihydroxybenzene, in which the hydroxyphenol and the alkylating agent are combined with an alkaline earth metal hydroxide or an alkaline earth metal oxide. The reaction is carried out in a dipolar neutral solvent containing a sulfoxide group, a sulfone group, or an amide group in the presence of a compound. However, this method uses specific solvents that are relatively expensive and have high boiling points as mentioned above, and referring to the various examples described in the specification, at most 0.5
It is understood that selective monoetherification is achieved using moles of methallyl chloride. However, in such a method, the yield of monoether is necessarily less than 50%, and in practice it is only 40%.
The yield is low. Furthermore, it has the disadvantage that recovering expensive unreacted catechol from this reaction mixture requires a delicate and expensive separation process. Although the method attempts to avoid the disadvantages associated with the use of large excesses of catechol, it uses an aprotic solvent containing amide groups, sulfoxide groups, ether groups, etc., particularly preferably N-methylpyrrolidone, and a specific amount of catechol. It is characterized by the use of alkali metal carbonates or bicarbonates. However, this method produces a relatively large amount of diether as a by-product, and separation of the monoether from the selected solvent by distillation is problematic, as monoethers are thermally unstable and the solvent has a high boiling point. It is. (4) JP-A-55-7291 This method involves the presence of a specific quaternary ammonium derivative or phosphonium derivative in a two-phase reaction medium consisting of a mixed solvent of water and a water-immiscible inert organic solvent with a boiling point of 50°C or higher. However, the monoether yield is generally low based on the starting catechol, and the special quaternary ammonium derivatives or phosphonium derivatives mentioned above are required to undergo a phase transition. It must be used as a catalyst. (5) JP-A-55-76833 This method consists of quite complicated steps, in which two phases exist in the first region, one being an organic solvent and the other being water, and a base and a quaternary ammonium derivative or phosphonium After mixing with the derivative, the organic layer is separated from the aqueous phase and heated to the reaction temperature in the second region to obtain the monoether. However, this method is basically the same as the method described in JP-A-55-7291, which uses a special quaternary ammonium derivative or phosphonium derivative, and involves the reaction being divided into the first and second regions. The operation is complicated. Furthermore, referring to the Examples, the yield based on converted catechol is high at about 90%, but the conversion rate of catechol is kept to about 60% or less in all cases. (6) JP-A-56-29584 This method uses at least one OH as a solvent.
This method uses polyhydroxyalkyl ether containing groups, uses a base such as sodium carbonate or sodium bicarbonate, and sodium dithionite as a reducing agent, and removes CO ₂ gas and water. 2,3-dihydro-2,2-dimethyl-7- in the next rearrangement and cyclization reaction without recovering this solvent.
It is used as a raw material for the production of benzofuranol. However, in this method, unreacted catechol is transferred to the next step and kept at a high temperature of about 180°C, making it difficult to recover and reuse it. As mentioned above, conventional methods for producing monoethers use relatively expensive and high-boiling point solvents, or use specific quaternary ammonium derivatives or phosphonium derivatives through two-phase heterogeneous reactions. Both have their own drawbacks as mentioned above. The object of the present invention is to provide a method for selectively producing the monoether of the present invention by simple operations using cheap and easily available ketones as a solvent, without using any special quaternary ammonium derivatives, phosphonium derivatives, etc. It is about providing. That is, the present invention relates to a method for producing a monoether in which catechol and methallyl chloride are reacted in the presence of a ketone solvent and a dehydrochlorinating agent, and more specifically, the present invention relates to a method for producing a monoether in which catechol and methallyl chloride are reacted in the presence of a ketone solvent and a dehydrochlorinating agent. The present invention relates to a method for producing monoether, which is characterized in that the amount used is specified within a certain range. In the present invention, as mentioned above, the reactivity is greatly affected by varying the amount of ketone solvent and dehydrochlorination agent used, and it is believed that proper use can produce surprising effects. I found it. The effects of the present invention will be specifically explained below. Tables 1 to 3 below summarize Examples and Comparative Examples, and show the amount of ketone solvent or dehydrochlorination agent used, the yield and selectivity of monoether, and the production of monoether and diether. The relationship between molar ratio (mono/di ratio) is shown. Here, acetone was used as a ketone solvent, K ₂ CO ₃ was used as a base of the dehydrochlorination agent, and KI was used as a catalyst. Table 1 shows the relationship between acetone and yield, etc. In the comparative example, 0.94% of acetone was added to 1g of catechol.
g is used. In the Examples, as the amount of acetone was gradually increased, the yield, selectivity, and mono/di ratio were significantly improved. This trend is shown in Figure 1, and as is clear from the figure, the amount of acetone used is
It is effective in the range of 1 to 10 parts by weight, particularly preferably in the range of 2 to 7 parts by weight. Furthermore
By decreasing K ₂ CO ₃ and KI, the effect becomes more obvious, and improvements are seen in both yield, selectivity, and mono/di ratio. Moreover, in this case, the reactivity was improved and the reaction time was sufficient to be less than half, so it became clear that there was a double effect. Tables 2 and 3 show the relationship between K ₂ CO ₃ or KI and yield, etc. From the table, K ₂ CO ₃ is catechol 1
It can be seen that excellent effects are expressed in the range of 0.3 to 1 mol to 1 mol of catechol, and 0 to 1 mol of KI to 1 mol of catechol. The ketone solvent used in the present invention has the general formula R ¹ COR ² (wherein R ¹ and R ² are an alkyl group having 1 to 6 carbon atoms or
(represents an alkylene group having 4 to 8 carbon atoms formed by bonding R ¹ and R ² ), and specific examples thereof include acetone, methyl ethyl ketone, diethyl ketone,
Examples include methyl isobutyl ketone and cyclohexanone. Acetone is particularly preferred. In the present invention, the dehydrochlorination agent consists of a base and a catalyst. Preferred bases include carbonates and bicarbonates of alkali metals, and amines having a pKa of 10 or more. Preferred catalysts include KI, NaI, etc. can be exemplified. Examples of alkali metal carbonates and bicarbonates include K ₂ CO ₃ , Na ₂ CO ₃ , KHCO ₃ and NaHCO ₃ , and examples of amines having a pKa of 10 or more include those of the general formula (In the formula, R ³ and R ⁴ are hydrogen or an alkyl group having 1 to 5 carbon atoms, or an alkylene group having 2 to 11 carbon atoms formed by bonding R ³ and R ⁴ , and R ⁵ is an alkylene group having 2 to 6 carbon atoms. Cyclic amidines represented by (representing an alkylene group) or general formula (In the formula, R ⁶ and R ⁷ are hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or
It is an alkylene group having 5 to 8 carbon atoms formed by bonding R ⁶ and R ⁷ , and R ⁸ is hydrogen, an alkyl group having 1 to 8 carbon atoms, or a phenyl group. can. Specific examples of the amidines mentioned above include:
1,8-diaza-bicyclo[5.4.0]-7-
Undecene (DBU), 1,6-diaza-bicyclo[4.3.0]-5-nonene, 1,5-diaza-bicyclo[4.2.0]-5-octene, 1.4-
Examples include diaza-bicyclo[3.3.0]-4-octene and 3-methyl-1.4-cyaza-bicyclo[3.3.0]-4-octene. Specific examples of amines include ethylamine, diethylamine, triethylamine, cyclohexylamine, butylamine, hexylamine, dicyclohexylamine, methylamine, dimethylamine, piperidine, and the like. The amount of base used in the present invention is in the range of 0.3 to 1 mol of alkali metal carbonate, 0.6 to 3 mol of alkali metal bicarbonate, and 0.3 to 3 mol of amines with pKa of 10 or more per 1 mol of catechol. Further, the amount of the catalyst used is preferably in the range of 0 to 1 mol per 1 mol of catechol. The amount of methallyl chloride used in the present invention is
Methallyl chloride per mole of catechol
It is preferably in the range of 0.6 to 1.4 mol. In the present invention, the reaction is preferably carried out at a temperature of about 50-150°C. In addition, in the case of the reaction under pressure, the pressure is not particularly limited because the pressure varies greatly depending on the type of solvent and the reaction temperature. In the present invention, a catalyst is not necessarily required, but since the reaction rate decreases in the absence of a catalyst, it is possible to achieve a high yield by lengthening the reaction time. It is preferable that it exists. Next, embodiments of the present invention will be specifically described. In the present invention, catechol, solvent, catalyst, and methallyl chloride may be mixed together in any order in the cold and then heated, or the mixture excluding methallyl chloride may be heated and then added. Methallyl chloride may also be added. After the reaction, the reaction solution is cooled to room temperature, and if crystals are present, the crystals and the solution are separated by filtration. The crystals are washed with a small amount of solvent, and the washing liquid is combined with the liquid. This crystal composition is an alkali metal carbonate, an alkali metal bicarbonate, an alkali metal chloride, and an alkali metal iodide, and can be reused as is or after treatment. Even if the crystal contains a large amount of alkali metal chloride, there is no particular problem in reusing the crystal. If necessary, this crystal may be reused after adding a small amount of water and heating it to take advantage of the solubility difference, dissolving salts other than alkali metal chlorides with heat, and removing a small amount of water. On the other hand, after removing the solvent and methallyl chloride from the liquid under reduced pressure, catechol is extracted with a small amount of water. The aqueous layer is reused after removing a small amount of water. The oil layer can be distilled to isolate only the monoether, but it can be used as it is as a raw material for producing 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran in the next rearrangement cyclization reaction. You can also. The method of the present invention described above has solvents, catalysts, etc. that are cheaper and easier to obtain than conventional methods, has high reactivity, produces less diether as a by-product, and can be used in a short time. It is characterized by high yield (yield based on the catechol used in the reaction) and high selectivity (yield based on converted catechol), and furthermore, catechol and catalyst can be easily recovered. It has many excellent effects. Next, the present invention will be explained with reference to Examples and Comparative Examples. Examples 1 to 10 and Comparative Example 1 In a 200 ml glass reactor equipped with a thermometer and a stirring device, 10 g (91 mmol) of catechol and acetone are added and dissolved. Next, potassium carbonate and potassium iodide were added and stirred, and nitrogen gas was introduced into the system to replace it with air to create a nitrogen gas atmosphere. The mixture was heated and 8.24 g (91 mmol) of methallyl chloride was added dropwise under reflux over a period of 10 minutes, followed by continued heating under reflux. After the reaction, the reaction solution was cooled to room temperature and filtered, the crystals were washed with a small amount of acetone, and the washing solution was mixed with the above solution. This mixed solution was diluted and analyzed by high performance liquid chromatography. The results are summarized in Table 1. Note that this mixed solution was processed separately, that is, acetone and methallyl chloride were removed under reduced pressure, and extraction was performed using chloroform and water, and the chloroform layer was
After drying with Mg ₂ SO ₄ , it was concentrated, and the residue was distilled under reduced pressure.
The identity of the monoether and diether was confirmed from the NMR spectrum and mass spectrum. Furthermore, unreacted catechol was recovered from the aqueous layer during extraction. These results were consistent with the results of the analysis using high performance liquid chromatography described above. An example in which acetone was used outside the scope of the present invention is referred to as Comparative Example 1, and the results are also shown. The reaction results are shown as yield, selectivity, and mono/di ratio. These are defined as follows. Yield is the number of moles of monoether produced relative to the number of moles of catechol used in the reaction, expressed as a percentage. Selectivity is the number of moles of monoether produced relative to the number of moles of catechol consumed, expressed as a percentage. The mono/di ratio is the number of moles of the produced monoether relative to the number of moles of the by-product diether.

【table】

[Table] Examples 11 to 13 and Comparative Examples 2 to 3 Using the same equipment as used in Examples 1 to 10, 11.0 g (100 mmol) of catechol and 34.8 g of acetone were added and dissolved. Next, 8.2 g (49.6 mmol) of potassium iodide and potassium carbonate were added and stirred to create a nitrogen gas atmosphere in the system. The mixture was heated and 9.05 g (100 mmol) of methallyl chloride was added over 10 minutes under reflux.
Heated under reflux for 15 hours. The results are shown in Table 2.

[Table] Examples 14 to 17 and Comparative Example 4 In Examples 11 to 13, 6.84 g of potassium carbonate
(49.6 mmol) and the reaction was carried out under the same conditions except that the amount of potassium iodide used was varied. The results are shown in Table 3.

[Table] Examples 18-25 Reactions were carried out according to the methods carried out in Examples 1-10. The results are shown in Table 4.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the yield (A), selectivity (B) and mono/di ratio (C) of the monoether of the present invention with respect to ketone/catechol (weight ratio).

Claims (1)

[Claims] 1. When reacting catechol and methallyl chloride in the presence of a solvent and a dehydrochlorination agent, the type of solvent is a ketone, and the amount of the solvent used is 1 to 1 part by weight per 1 part by weight of catechol. The dehydrochlorination agent consists of a base or a base and a catalyst, and the type of base is one or two of alkali metal carbonates, bicarbonates, and amines with a pKa of 10 or more.
species or more, and the amount of base used is 0.3 to 1 mol of alkali metal carbonate and 0.6 to 3 mol of alkali metal bicarbonate per 1 mol of catechol.
The ratio of amines with a pKa of 10 or more is 0.3 to 3 moles, the type of catalyst is one or more of KI and NaI, and the amount of catalyst used is 0 to 1 mole per mole of catechol. A method for producing ortho-methallyloxyphenol. 2 The ketone solvent has the general formula R ¹ COR ² (where R ¹ and R ² are an alkyl group having 1 to 6 carbon atoms or
2. The manufacturing method according to claim 1, wherein R ¹ and R ² are bonded together to represent an alkylene group having 4 to 8 carbon atoms. 3 Carbonates or bicarbonates of alkali metals
_K2CO3 , _{Na2CO3 or KHCO3 , NaHCO3} ,
Amines with a pKa of 10 or more have the general formula (In the formula, R ³ and R ⁴ are hydrogen or an alkyl group having 1 to 5 carbon atoms, or an alkylene group having 2 to 11 carbon atoms formed by bonding R ³ and R ⁴ , and R ⁵ is an alkylene group having 2 to 6 carbon atoms. Cyclic amidines represented by (representing an alkylene group) or general formula (In the formula, R ⁶ and R ⁷ are hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or R ⁶
and R ⁷ are bonded together to form an alkylene group having 5 to 8 carbon atoms, and R ⁸ is hydrogen, an alkyl group having 1 to 8 carbon atoms, or a phenyl group. The manufacturing method according to item 1. 4. The manufacturing method according to claim 1, wherein methallyl chloride is used in a ratio of about 0.6 to 1.4 moles per mole of catechol. 5. The manufacturing method according to claim 1, wherein the reaction is carried out at a temperature of about 50 to 150°C.