Selective hydrogenation method for substituted bicyclo [2.2. 1] hept-2, 5-diene

Abstract

The invention discloses a selective hydrogenation method of substituted bicyclo [2.2. 1] heptyl-2, 5-diene, and is characterized in that the method comprises the following steps: in a hydrogen atmosphere, stirring a mixture containing a substituted bicyclo [2.2. 1] heptyl-2, 5-diene compound, a Raney nickel catalyst and a solvent, and reacting to obtain a hydrogenation product. According to the method, raney nickel is used as a catalyst, and one carbon-carbon double bond in a compound with a substituted bicyclo [2.2. 1] hept-2, 5-diene structure is selectively hydrogenated in a hydrogen atmosphere. The catalyst used in the method is relatively cheap and convenient to recover, so that the cost can be greatly saved, and the unilateral hydrogenated substituted bicyclo [2.2. 1] hept-2-ene product can be obtained with high selectivity.

Description

Technical Field

[0001] The present application relates to a method for selective hydrogenation of substituted bicyclo[2.2.1]hept-2,5-diene, belonging to the field of catalyst hydrogenation. Background Art

[0002] Substituted bicyclo[2.2.1]hept-2,5-diene compounds can be generated by cyclization of five-membered ring dienes with alkynes. When the substituents are different, the chemical environment of the two carbon-carbon double bonds in their structure is different. Selective catalytic hydrogenation can be carried out by controlling the reaction conditions and the type of catalyst to obtain substituted bicyclo[2.2.1]hept-2-ene products with only one double bond hydrogenated, which can be further aromatized or undergo a reverse Diels-Alder decomposition reaction to generate substituted five-membered ring aromatic compounds. However, the existing technology is limited to the use of expensive palladium catalysts, and the selectivity is improved by reducing the catalytic hydrogenation activity through means such as loading and poisoning; the application of cheaper Raney nickel catalysts is basically limited to the reduction of carbonyl and cyanide groups, and is less used in the hydrogenation of carbon-carbon double bonds, and there is almost no selective hydrogenation of bicyclo[2.2.1]hept-2,5-diene compounds. The application of this type of catalyst in this regard remains to be developed. Summary of the invention

[0003] The present invention relates to a method for selectively hydrogenating substituted bicyclo[2.2.1]hepta-2,5-diene using a Raney nickel catalyst.

[0004] According to one aspect of the present application, a method for selective hydrogenation of substituted bicyclo[2.2.1]hept-2,5-diene is provided, the method comprising:

[0005] Under a hydrogen atmosphere, a mixture containing a substituted bicyclo[2.2.1]hept-2,5-diene compound, a Raney nickel catalyst, and a solvent is stirred and reacted to obtain a hydrogenated product;

[0006] The substituted bicyclo[2.2.1]hept-2,5-diene compound has a structure shown in Formula I;

[0007] The hydrogenation product has a structure shown in Formula II;

[0008]

[0009] In Formula I and Formula II, R1, R2, R3, and R4 are independently selected from one of -H, -NO2, -SO3R, -F, -Cl, -Br, -I, -CO2R, -OR, -CH2OR, -CH2R, -CF3, and -C6H4R;

[0010] R is selected from one of hydrogen, -CH3, -C2H5, -C3H7, -C4H9;

[0011] In Formula I and Formula II, X is selected from one of -CH2, -NH, -O, and -S.

[0012] Optionally, the Raney nickel catalyst is selected from at least one of RTH-2110, RTH-2140, RTH-2124, RTH-3110, RTH-3110S, RTH-3140, RTH-3124, RTH-4110, RTH-5110, and alkali-treated nickel-aluminum alloy.

[0013] Optionally, the mass ratio of the substituted bicyclo[2.2.1]hept-2,5-diene compound to the Raney nickel catalyst is 1 to 100:1.

[0014] Optionally, the mass ratio of the substituted bicyclo[2.2.1]hept-2,5-diene compound to the Raney nickel catalyst is selected from any value of 1:1, 10:1, 20:1, 50:1, 100:1 or a range between any two of the above.

[0015] Optionally, the solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, ether, tetrahydrofuran, 1,4-dioxane, methyl acetate, ethyl acetate, and ethyl formate.

[0016] Optionally, the mass volume ratio of the substituted bicyclo[2.2.1]hept-2,5-diene compound to the solvent is 0.1-10 g:10 mL.

[0017] Optionally, the mass volume ratio of the substituted bicyclo[2.2.1]hept-2,5-diene compound to the solvent is selected from any value of 0.1 g / 10 mL, 0.5 g / 10 mL, 1 g / 10 mL, 5 g / 10 mL, 10 g / 10 mL, or a range between any two of the above values.

[0018] Optionally, the hydrogen atmosphere is derived from a hydrogen gas stream and / or pressurized hydrogen.

[0019] Optionally, the flow rate of the hydrogen gas flow is 10 to 100 mL / min.

[0020] Optionally, the flow rate of the hydrogen gas flow is selected from any value of 10 mL / min, 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min, 90 mL / min, 100 mL / min or a range between any two of the above.

[0021] Optionally, the pressure of the pressurized hydrogen is 0.1-1 MPa.

[0022] Optionally, the pressure of the pressurized hydrogen is selected from any value of 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa or a range between any two of the above values.

[0023] Optionally, the reaction is carried out in an ice bath, a water bath or an air bath.

[0024] Optionally, the reaction temperature is 0 to 30° C., and the reaction time is 0.5 to 48 h.

[0025] Optionally, the reaction temperature is selected from any value of 0°C, 10°C, 20°C, 30°C or a range between any two of the above values.

[0026] Optionally, the reaction time is selected from any value of 0.5h, 1h, 2h, 4h, 6h, 8h, 12h, 24h, 48h or a range between any two of the above.

[0027] Optionally, the reaction is carried out under magnetic stirring or mechanical stirring.

[0028] Optionally, the stirring speed is 200-800 rpm.

[0029] Optionally, the stirring speed is selected from any value of 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or a range between any two of the above values.

[0030] Alternatively, the selective hydrogenation reaction of the substituted bicyclo[2.2.1]hept-2,5-diene is as follows:

[0031]

[0032] Wherein, R1, R2, R3, and R4 are independently selected from -H, -OH, -NO2, -SO3R, -F, -Cl, -Br, -I, -CO2H, -CO2R, -OR, -CH2OR, -CH3, -CH2R, -CF3, -C6H4R, etc.;

[0033] R is selected from one of hydrogen, -CH3, -C2H5, -C3H7, -C4H9;

[0034] X is selected from one of CH2, NH, O and S.

[0035] The beneficial effects of this application include:

[0036] The present invention uses cheap Raney nickel as a catalyst to efficiently and selectively hydrogenate substituted bicyclo[2.2.1]hept-2,5-diene compounds. Compared with traditional palladium catalysts, the catalyst is low in cost, easy to recycle, and can be reused, which greatly reduces production costs and improves reaction efficiency. DETAILED DESCRIPTION

[0037] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0038] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0039] Unless otherwise specified, the substrates involved in this application are all prepared by Diels-Alder reaction, and the reaction formula is as follows:

[0040]

[0041] Wherein, R1, R2, R3, and R4 are independently selected from -H, -OH, -NO2, -SO3R, -F, -Cl, -Br, -I, -CO2H, -CO2R, -OR, -CH2OR, -CH3, -CH2R, -CF3, -C6H4R, etc.;

[0042] R is selected from one of hydrogen, -CH3, -C2H5, -C3H7, -C4H9;

[0043] X is selected from one of CH2, NH, O and S.

[0044] Gas phase analysis was performed using Agilent 7890A GC.

[0045] The conversion rate and product selectivity in the examples of this application are calculated as follows:

[0046] Conversion rate [mol%] = (n0-n) / n0×100%

[0047] Product selectivity [mol%] = n x / (n0-n)×100%

[0048] In the formula of conversion rate and product selectivity, 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].

[0049] Example 1: Selective hydrogenation of 2,3-bis(trifluoromethyl)bicyclo[2.2.1]hept-2,5-diene

[0050] In a 50mL three-necked flask, 0.5g of 2,3-bis(trifluoromethyl)bicyclo[2.2.1]hept-2,5-diene was added and dissolved in 10mL of tetrahydrofuran, and 0.1g of RTH-2110 was added, and hydrogen was introduced at 40mL / min, and stirred at 500rpm at 20°C for 12h. After the reaction was completed, qualitative and quantitative analysis by gas chromatography showed that the raw material was completely converted; the obtained products were separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product was 89%.

[0051] The reaction formula is as follows:

[0052]

[0053] Example 2: Selective hydrogenation of 1,1'-(7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-di)bis(ethan-1-one)

[0054] In a 50mL three-necked flask, add 1g of 1,1'-(7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-di)bis(ethyl-1-one) dissolved in 10mL of isopropanol, add 0.5g of RTH-2110, introduce hydrogen at 40mL / min, and stir at 500rpm for 12h at 20°C. After the reaction is completed, qualitative and quantitative analysis by gas chromatography shows that the raw material conversion rate is 82%; the obtained products are separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product is 90%.

[0055]

[0056] Example 3: Selective hydrogenation of dimethyl 7-azabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylate

[0057] In a 50mL three-necked flask, 1g of 7-azabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester was dissolved in 10mL of methyl acetate, and 0.5g of RTH-2110 was added. Hydrogen was introduced at 40mL / min, and stirred at 500rpm for 12h at 20°C. After the reaction was completed, the qualitative and quantitative analysis by gas chromatography showed a raw material conversion rate of 78%; the obtained products were separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product was 95%.

[0058] The reaction formula is as follows:

[0059]

[0060] Example 4: Selective hydrogenation of 2,3-bis(acetyloxy)bicyclo[2.2.1]hept-2,5-diene

[0061] In a 50mL three-necked flask, 1g of 2,3-bis(acetoxy)bicyclo[2.2.1]hept-2,5-diene was added and dissolved in 10mL of ethyl acetate, and 0.2g of RTH-2110 was added. Hydrogen was introduced at 40mL / min, and stirred at 500rpm for 12h at 15°C. After the reaction was completed, qualitative and quantitative analysis by gas chromatography showed a raw material conversion rate of 65%; the obtained products were separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product was 98%.

[0062] The reaction formula is as follows:

[0063]

[0064] Example 5: Selective hydrogenation of dimethyl 7-thiabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylate

[0065] In a 50mL three-necked flask, add 1g of 7-thiabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester and dissolve it in 10mL of methyl acetate, add 0.2g of RTH-2110, introduce hydrogen at 40mL / min, and stir at 500rpm for 24h at 10°C. After the reaction is completed, qualitative and quantitative analysis by gas chromatography shows that the raw material conversion rate is 89%; the obtained products are separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product is 95%.

[0066] The reaction formula is as follows:

[0067]

[0068] Example 6: Selective hydrogenation of 2,3-bis(acetyloxy)-7-oxabicyclo[2.2.1]hept-2,5-diene

[0069] In a 50mL three-necked flask, 1g of 2,3-bis(acetyloxy)-7-oxabicyclo[2.2.1]hept-2,5-diene was added and dissolved in 10mL of ethyl acetate, and 0.2g of RTH-3110 was added. Hydrogen was introduced at 40mL / min, and stirred at 600rpm at 10°C for 1h. After the reaction was completed, qualitative and quantitative analysis by gas chromatography showed that the raw material was completely converted; the obtained products were separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product was 95%.

[0070] The reaction formula is as follows:

[0071]

[0072] Example 7: Selective hydrogenation of dimethyl 7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylate

[0073] In a 50mL three-necked flask, 1g of 7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester was added and dissolved in 10mL of methyl acetate, and 0.1g of RTH-3110 was added, and hydrogen was introduced at 20mL / min, and stirred at 600rpm at 20°C for 7h. After the reaction was completed, qualitative and quantitative analysis by gas chromatography showed that the raw material was completely converted; the obtained products were separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product was 91%.

[0074] The reaction formula is as follows:

[0075]

[0076] Example 8: Selective hydrogenation of diethyl 7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylate

[0077] In a 50mL three-necked flask, add 0.5g of 7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid diethyl ester and dissolve it in 10mL of ethyl acetate, add 0.1g of RTH-3110S, introduce hydrogen at 20mL / min, and stir at 600rpm for 6h at 20°C. After the reaction is completed, qualitative and quantitative analysis by gas chromatography shows that the raw material is completely converted; the obtained product is separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product is 91%.

[0078] The reaction formula is as follows:

[0079]

[0080] Example 9: Selective hydrogenation of dimethyl 1,4-dichloro-7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-disulfonate

[0081] In a 50mL pressure-resistant stainless steel reactor, 2g of 1,4-dichloro-7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-disulfonic acid dimethyl ester was added and dissolved in 20mL of methanol, and 0.1g of RTH-4110 was added, and 0.5MPa of hydrogen was charged, and stirred at 300rpm for 8h in an ice bath at 0℃. After the reaction was completed, the qualitative and quantitative analysis by gas chromatography showed that the raw material was completely converted; the obtained products were separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product was 76%.

[0082] The reaction formula is as follows:

[0083]

[0084] Example 10: Selective hydrogenation of 2,3-dihexyl-bicyclo[2.2.1]hept-2,5-diene

[0085] In a 50mL pressure-resistant stainless steel reactor, 2g of 2,3-dihexyl-bicyclo[2.2.1]hept-2,5-diene was added and dissolved in 20mL of methanol, and 0.5g of RTH-5110 was added, and 1MPa of hydrogen was charged, and stirred at 300rpm for 12h in a 30°C water bath. After the reaction was completed, the qualitative and quantitative analysis by gas chromatography showed that the raw material was completely converted; the obtained products were separated by column chromatography (petroleum ether: ethyl acetate = 5:1), and the selectivity of the unilateral double bond hydrogenation product was 65%.

[0086] The reaction formula is as follows:

[0087]

[0088] 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 the selective hydrogenation of substituted bicyclo[2.2.1]hept-2,5-dienes, characterized in that: The method comprises: Under a hydrogen atmosphere, a mixture containing a substituted bicyclo[2.2.1]hept-2,5-diene compound, a Raney nickel catalyst, and a solvent is stirred and reacted to obtain a hydrogenated product; The substituted bicyclo[2.2.1]hept-2,5-diene compound has a structure shown in Formula I; The hydrogenation product has a structure shown in Formula II; In Formula I and Formula II, R1, R2, R3, and R4 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, -C4H9; In Formula I and Formula II, X is selected from one of -CH2, -NH, -O, and -S.

2. The method according to claim 1, characterized in that The Raney nickel catalyst is selected from at least one of RTH-2110, RTH-2140, RTH-2124, RTH-3110, RTH-3110S, RTH-3140, RTH-3124, RTH-4110, RTH-5110, and alkali-treated nickel-aluminum alloy.

3. The method according to claim 1, characterized in that The mass ratio of the substituted bicyclo[2.2.1]hept-2,5-diene compound to the Raney nickel catalyst is 1-100:

1.

4. The method according to claim 1, characterized in that The solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, ether, tetrahydrofuran, 1,4-dioxane, methyl acetate, ethyl acetate, and ethyl formate.

5. The method according to claim 1, characterized in that The mass volume ratio of the substituted bicyclo[2.2.1]hept-2,5-diene compound to the solvent is 0.1-10 g:10 mL.

6. The method according to claim 1, characterized in that The hydrogen atmosphere comes from hydrogen gas flow and / or pressurized hydrogen.

7. The method according to claim 6, characterized in that The flow rate of the hydrogen gas flow is 10 to 100 mL / min.

8. The method according to claim 6, characterized in that The pressure of the pressurized hydrogen is 0.1-1 MPa.

9. The method according to claim 1, characterized in that: The reaction temperature is 0-30°C, and the reaction time is 0.5-48h.

10. The method according to claim 1, characterized in that The stirring speed is 200-800 rpm.

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