Preparation method for catalyzing 7-oxabicyclo [2.2. 1] hept-2, 5-diene compound
By catalyzing the deoxyarbostomization reaction of 7-oxabicyclo[2.2.1]hepta-2,5-diene under mild conditions, the catalyst has high risk and low selectivity in the prior art. The problem of this has achieved efficient and safe compound conversion and reduced production costs.
Patent Information
- Application Number
- CN202310720901.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-15
- Publication Date
- 2024-12-17
AI Technical Summary
In the catalytic deoxyarbosectomylation reaction of 7-oxabicyclic[2.2.1]heptan-2,5-diene compounds, the use of low-priced active metals requires harsh conditions, high risk, or the use of precious metals causes Environmental pollution and low selectivity, lacking cheap, efficient and highly selective catalysts.
Using metal carbonyl compounds such as molybdenum hexacarbonyl and tungsten hexacarbonyl as catalysts, react at pressure-resistant pressure with a mixture of 7-oxabicyclic[2.2.1]heptanium-2,5-diene compounds and solvents in a closed container The reaction was heated in the kettle, deoxyaromatic was carried out, and the reaction conditions were controlled at 120-180°C, and the reaction time was 2-24 hours.
Achieve efficient and selective conversion of 7-oxabicyclic[2.2.1]heptan-2,5-diene structure into substituted aromatic compounds, using cheap catalysts, reducing production costs, improving safety, and Stable in the air and widely applicable.
Smart Images
Figure BDA0004291383880000011 
Figure BDA0004291383880000031 
Figure BDA0004291383880000041
Abstract
Description
Technical Field
[0001] The present application relates to a method for preparing catalytic 7-oxabicyclo[2.2.1]hept-2,5-diene compounds, belonging to the field of metal organic catalysis. Background Art
[0002] Furan and its derivatives from biomass have cis-conjugated carbon-carbon double bonds, and are very easy to undergo cycloaddition reactions with alkynes to obtain compounds with a 7-oxabicyclo[2.2.1]hept-2,5-diene structure. Deoxyaromatization of such compounds can obtain aromatic compounds with substituents. However, harsh conditions are usually required to achieve this reaction. The existing technology mainly focuses on the use of low-cost active metals for reduction, which needs to be carried out under low temperature conditions, is sensitive to water and air, and is highly dangerous; or the use of precious metals plus reducing agents for catalytic reduction, which causes great environmental pollution, is prone to side reactions such as rearrangement, and has low selectivity. In summary, the art still lacks a method for deoxyaromatization of such compounds using a cheap, efficient, highly selective, stable and safe catalyst. Summary of the invention
[0003] According to one aspect of the present application, a method for preparing a catalytic 7-oxabicyclo[2.2.1]hept-2,5-diene compound is provided, the preparation method comprising:
[0004] In a sealed container, a mixture containing a 7-oxabicyclo[2.2.1]hept-2,5-diene compound, a metal carbonyl compound and a solvent is reacted to obtain a deoxyaromatization product;
[0005] The 7-oxabicyclo[2.2.1]hept-2,5-diene compound has a structure shown in Formula I;
[0006] The deoxyaromatization product has the structure shown in Formula II;
[0007]
[0008] In Formula I and Formula II, R1, R2, R3, R4, R5, and R6 are independently selected from one of -H, -NO2, -SO3R, -F, -Cl, -Br, -I, -CO2R, -OR, -CH2OR, -CH2R, -CF3, and -C6H4R;
[0009] R is selected from one of hydrogen, -CH3, -C2H5, -C3H7, and -C4H9.
[0010] The present application is a method for deoxygenation aromatization of 7-oxabicyclo[2.2.1]hept-2,5-diene catalyzed by a metal carbonyl compound, comprising the following steps:
[0011] The 7-oxabicyclo[2.2.1]hept-2,5-diene substrate and the catalyst are dissolved in a solvent and heated in a pressure-resistant reactor for reaction.
[0012] Optionally, the catalyst is a metal carbonyl compound, and the metal carbonyl compound is selected from molybdenum hexacarbonyl and / or tungsten hexacarbonyl.
[0013] Optionally, the molar ratio of the 7-oxabicyclo[2.2.1]hept-2,5-diene compound to the metal carbonyl compound is 1:10 to 1 mol.
[0014] Optionally, the molar ratio of the 7-oxabicyclo[2.2.1]hept-2,5-diene compound to the metal carbonyl compound is selected from any value of 1:1, 2:1, 5:1, 8:1, 10:1 or a range between any two of the above.
[0015] Optionally, the molar volume ratio of the 7-oxabicyclo[2.2.1]hept-2,5-diene compound to the solvent is 0.01 to 1:1 mol / L.
[0016] Optionally, the molar volume ratio of the 7-oxabicyclo[2.2.1]hept-2,5-diene compound to the solvent is selected from any value of 0.01:1 mol / L, 0.1:1 mol / L, 0.5:1 mol / L, 1:1 mol / L or a range between any two of the above.
[0017] Optionally, the solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, ether, acetonitrile, tetrahydrofuran, 1,4-dioxane, methyl isobutyl ketone, methyl acetate, ethyl acetate, ethyl formate, and butyl acetate.
[0018] Optionally, the reaction is carried out in a pressure-resistant container, and the reaction is carried out in an ice bath, a water bath, or an air bath.
[0019] Optionally, the reaction temperature is 120-180°C.
[0020] Optionally, the reaction temperature is selected from any value of 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C or a range between any two of the above values.
[0021] Optionally, the reaction time is 2 to 24 hours.
[0022] Optionally, the reaction time is any value among 2h, 4h, 6h, 8h, 12h, 18h, 24h, or a range between any two of the above.
[0023] The metal carbonyl compound catalyzes the deoxyaromatization reaction of 7-oxabicyclo[2.2.1]hept-2,5-diene substrates as follows:
[0024]
[0025] in,
[0026] R1, R2, R3, R4, R5, R6=-H, -OH, -NO2, -SO3R, -F, -Cl, -Br, -I, -CO2H, -CO2R, -OR, -CH2OR, -CH3, -CH2R, -CF3, -C6H4R, etc.
[0027] R is selected from one of hydrogen, -CH3, -C2H5, -C3H7, -C4H9;
[0028] M=Mo or W.
[0029] The beneficial effects of this application include:
[0030] The present application provides a method for the deoxygenation aromatization of 7-oxabicyclo[2.2.1]hept-2,5-diene substrates catalyzed by metal carbonyl compounds. The method uses metal carbonyl compounds as catalysts, and can efficiently and highly selectively deoxygenate aromatize substrates having a 7-oxabicyclo[2.2.1]hept-2,5-diene structure to obtain aromatic compounds. The catalyst used in the method is relatively cheap, stable in air, and has a wide range of substrate applicability, which can reduce production costs and improve safety. Using cheap metal carbonyl compounds as deoxygenation aromatization catalysts, substrates having a 7-oxabicyclo[2.2.1]hept-2,5-diene structure are efficiently and highly selectively aromatized under relatively mild conditions to obtain substituted aromatic compounds, and are widely applicable to various substituents. DETAILED DESCRIPTION
[0031] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.
[0032] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.
[0033] The 7-oxabicyclo[2.2.1]hept-2,5-diene substrates involved in the following examples, unless otherwise specified, are prepared by the Diels-Alder reaction of substituted furans and substituted alkynes, and the reaction formula is as follows:
[0034]
[0035] in,
[0036] R1, R2, R3, R4, R5, R6=-H, -OH, -NO2, -SO3R, -F, -Cl, -Br, -I, -CO2H, -CO2R, -OR, -CH2OR, -CH3,, -CH2R, -CF3, -C6H4R, etc.
[0037] R is selected from one of hydrogen, -CH3, -C2H5, -C3H7, and -C4H9.
[0038] The conversion rate and product yield in the examples of this application are calculated as follows:
[0039] Conversion rate [mol%] = (n0-n) / n0×100%
[0040] Product yield [mol%] = n x / n0×100%
[0041] In the formula, n0 is the amount of substrate (calculated as olefin) added before the reaction [mol], n is the amount of substrate remaining after the reaction [mol], and n x The amount of product produced during the reaction [mol].
[0042] Example 1
[0043] In a 15mL stainless steel pressure reactor, 1-methyl-7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester 1mmol (224mg), hexacarbonyl tungsten 0.5mmol (176mg), acetonitrile 5mL were added. After the container was sealed, it was heated in an oil bath at 150°C and reacted for 24h. After the reaction was completed, the reaction solution was filtered, concentrated, and purified by column chromatography (petroleum ether: ethyl acetate = 5:1). The raw material conversion rate was 100%, and the product yield was 78%.
[0044] The reaction formula is as follows:
[0045]
[0046] Example 2
[0047] In a 15mL stainless steel pressure reactor, add 1mmol (326mg) of 7-oxabicyclo[2.2.1]hept-2,5-diene-2,3,5,6-tetracarboxylic acid tetramethyl ester, 0.5mmol (176mg) of hexacarbonyl tungsten, and 5mL of acetonitrile. After the container is sealed, heat it in an oil bath at 150°C and react for 8h. After the reaction is completed, the reaction solution is filtered, concentrated, and purified by column chromatography (petroleum ether: ethyl acetate = 5:1). The raw material conversion rate is 72%, and the product yield is 53%.
[0048] The reaction formula is as follows:
[0049]
[0050] Embodiment 3-5
[0051] In a 15mL stainless steel pressure reactor, add 1mmol (268mg) of 7-oxabicyclo[2.2.1]hept-2,5-diene-1,2,4-tricarboxylic acid trimethyl ester, 0.5mmol of catalyst (tungsten hexacarbonyl or molybdenum hexacarbonyl) and acetonitrile, seal the container, heat in an oil bath at 150°C, and react for 8h. After the reaction is completed, filter and concentrate the reaction solution, separate and purify by column chromatography (petroleum ether: ethyl acetate = 5:1).
[0052] The reaction formula is as follows:
[0053]
[0054] The specific conditions are as follows:
[0055]
[0056] Example 6
[0057] In a 15mL stainless steel pressure reactor, add 1mmol (268mg) of 7-oxabicyclo[2.2.1]hept-2,5-diene-2,3,5-tricarboxylic acid trimethyl ester, 0.5mmol (132mg) of hexacarbonyl molybdenum, and 2mL of acetonitrile. After the container is sealed, heat it in an oil bath at 150°C and react for 8h. After the reaction is completed, the reaction solution is filtered, concentrated, and purified by column chromatography (petroleum ether: ethyl acetate = 5:1). The raw material conversion rate is 100%, and the product yield is 91%.
[0058] The reaction formula is as follows:
[0059]
[0060] Example 7
[0061] In a 15mL stainless steel pressure reactor, 1-formyl-7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester 1mmol (238mg), hexacarbonyl molybdenum 0.5mmol (132mg), and acetonitrile 2mL were added. After the container was sealed, it was heated in an oil bath at 150°C and reacted for 8h. After the reaction was completed, the reaction solution was filtered, concentrated, and purified by column chromatography (petroleum ether: ethyl acetate = 5:1). The raw material conversion rate was 100%, and the product yield was 88%.
[0062] The reaction formula is as follows:
[0063]
[0064] Example 8
[0065] In a 15mL stainless steel pressure reactor, 1-(acetoxymethyl)-7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester 1mmol (282mg), hexacarbonyl molybdenum 0.5mmol (132mg), and methyl isobutyl ketone 2mL were added. After the container was sealed, it was heated in an oil bath at 150°C and reacted for 8h. After the reaction was completed, the reaction solution was filtered, concentrated, and purified by column chromatography (petroleum ether: ethyl acetate = 5:1). The raw material conversion rate was 95%, and the product yield was 92%.
[0066] The reaction formula is as follows:
[0067]
[0068] Example 9
[0069] In a 15mL stainless steel pressure reactor, 1mmol (289mg) of 5-bromo-7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester, 0.5mmol (132mg) of hexacarbonyl molybdenum, and 2mL of tetrahydrofuran were added. After the container was sealed, it was heated in an oil bath at 150°C and reacted for 8h. After the reaction was completed, the reaction solution was filtered, concentrated, and purified by column chromatography (petroleum ether: ethyl acetate = 5:1). The raw material conversion rate was 100%, and the product yield was 89%.
[0070] The reaction formula is as follows:
[0071]
[0072] Example 10
[0073] In a 15mL stainless steel pressure reactor, 1-formyl-4-methyl-7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester 1mmol (252mg), hexacarbonyl molybdenum 0.5mmol (132mg), butyl acetate 2mL were added, the container was sealed, and the oil bath was heated at 150°C for 8h. After the reaction was completed, the reaction solution was filtered, concentrated, and purified by column chromatography (petroleum ether: ethyl acetate = 5:1). The raw material conversion rate was 99%, and the product yield was 93%.
[0074] The reaction formula is as follows:
[0075]
[0076] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for preparing 7-oxabicyclo[2.2.1]hept-2,5-diene compounds, characterized in that: The preparation method comprises: In a sealed container, a mixture containing a 7-oxabicyclo[2.2.1]hept-2,5-diene compound, a metal carbonyl compound and a solvent is reacted to obtain a deoxyaromatization product; The 7-oxabicyclo[2.2.1]hept-2,5-diene compound has a structure shown in Formula I; The deoxyaromatization product has the structure shown in Formula II; In Formula I and Formula II, R1, R2, R3, R4, R5, and R6 are independently selected from one of -H, -NO2, -SO3R, -F, -Cl, -Br, -I, -CO2R, -OR, -CH2OR, -CH2R, -CF3, and -C6H4R; R is selected from one of hydrogen, -CH3, -C2H5, -C3H7, and -C4H9.
2. The preparation method according to claim 1, characterized in that: The metal carbonyl compound is selected from molybdenum hexacarbonyl and / or tungsten hexacarbonyl.
3. The preparation method according to claim 1, characterized in that: The molar ratio of the 7-oxabicyclo[2.2.1]hept-2,5-diene compound to the metal carbonyl compound is 1:10 to 1 mol.
4. The preparation method according to claim 1, characterized in that: The molar volume ratio of the 7-oxabicyclo[2.2.1]hept-2,5-diene compound to the solvent is 0.01 to 1:1 mol / L.
5. The preparation method according to claim 1, characterized in that: The solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, ether, acetonitrile, tetrahydrofuran, 1,4-dioxane, methyl isobutyl ketone, methyl acetate, ethyl acetate, ethyl formate and butyl acetate.
6. The preparation method according to claim 1, characterized in that: The reaction temperature is 120-180°C.
7. The preparation method according to claim 1, characterized in that: The reaction time is 2 to 24 hours.