CN111822047B - A method for the catalytic synthesis of indole derivatives supported by a magnetic mesoporous polymeric ionic liquid - Google Patents

Abstract

The invention discloses a preparation method of a magnetic mesoporous polymeric ionic liquid catalyst, comprising: 1) dissolving equimolar amounts of 2-bromoethyl acrylate and triethylenediamine in methanol solution, under vacuum nitrogen protection, at 50-60 ℃ heating under reflux for a certain period of time, concentrating under reduced pressure, and drying in vacuo to obtain a light yellow viscous ionic liquid; 2) combining the ionic liquid obtained in step 1) with endene-modified Fe ₃ O ₄ , divinylbenzene, azodiiso Butyronitrile is dissolved in methanol, refluxed under vacuum heating at 60-80°C until the reaction is complete, and vacuum drying after the reaction is completed to obtain the final catalyst. The invention also discloses the above catalyst and its application in synthesizing indole derivatives and seven-membered condensed indole. The method has high yield, simple operation, simple catalyst recovery, good reusability of the catalytic reaction system, mild reaction conditions, and has a good prospect of green industrialization.

Description

A method for the catalytic synthesis of indole derivatives supported by a magnetic mesoporous polymeric ionic liquid

Technical field:

The invention relates to the technical field of organic compound synthesis, in particular to a magnetic mesoporous polymeric ionic liquid catalyst and its application in the preparation of multi-component synthetic indole derivatives and seven-membered ring fused indole.

Background technique:

Indole compounds are an important fine chemical raw material, which has become a hot heterocyclic chemical raw material at home and abroad, and has a broad development prospect. Indole compounds exist widely in nature, most of them have biological activity, and are widely used in the fields of pesticides, medicines, dyes, feed, food and additives. The multi-component reaction, that is, a one-pot method, can directly obtain molecules with complex structures, which is an effective method for synthesizing molecular diversity and complexity, and is economical and environmentally friendly. Therefore, the preparation of indole compounds by multi-component reaction is cost-effective, simple and easy to operate, and environmentally friendly.

In recent years, polymeric ionic liquids, as a new class of new ionic polymers, have certain special physical and chemical properties, which combine ionic liquids into the polymer backbone, which combines the dual advantages of ionic liquids and high-molecular polymers. Mesoporous polymeric ionic liquids are a new class of porous materials which are copolymerized by ionic liquids, cross-linking agents and other monomers. They have the dual characteristics of mesoporous materials and polymeric ionic liquids. Mesoporous polymeric ionic liquids with tunable porosity and easy modification of functional groups by designing task-specific ionic moieties are widely used in membranes, electrolytes for electrochemical supercapacitors, pH, heat, light, solvent, and _CO responsiveness. materials, etc. The preparation of supported polymeric ionic liquids is more conducive to the recovery and recycling after the reaction. Using superparamagnetic nanomaterials as a carrier, compared with traditional catalysts, not only has a mesoporous structure, which can greatly improve the catalytic efficiency, but also makes it easier to separate the catalyst from the product after the reaction, which better solves the problem of catalyst recovery and separation.

Invention content:

The object of the present invention is to replace the traditional method for catalyzing the synthesis of indole compounds, and to provide a kind of environment-friendly, efficient and recyclable indole derivatives and the synthesis method of seven-membered condensed indole.

The invention provides a preparation method of a magnetic mesoporous polymeric ionic liquid catalyst, comprising:

1) Dissolve equimolar amounts of 2-bromoethyl acrylate and triethylenediamine in methanol solution, protect with vacuum nitrogen, heat under reflux at 50-60 °C for a certain period of time, concentrate under reduced pressure, and vacuum dry to obtain a pale yellow viscous liquid. ionic liquid;

2) Dissolve the ionic liquid obtained in step 1) and the olefin-modified Fe ₃ O ₄ , divinylbenzene and initiator in methanol, heat under vacuum at 60-80° C. to reflux until the reaction is complete, and vacuum dry after the reaction is completed to obtain the final product. catalyst.

In one embodiment according to the present invention, the molecular structure of the ionic liquid is shown in structural formula I.

In one embodiment according to the present invention, the molar ratio of the terminal alkene-modified Fe ₃ O ₄ , the initiator, the divinylbenzene and the ionic liquid in step 2) is 1:1:4:4. Preferably, the initiator is azobisisobutyronitrile.

The present invention also provides a magnetic mesoporous polymeric ionic liquid catalyst prepared according to the above-mentioned preparation method.

In one embodiment according to the present invention, the molecular structure of the catalyst is shown in structural formula II.

Another aspect of the present invention provides a method for synthesizing an indole derivative and a seven-membered ring fused indole, comprising:

Using ethanol as a solvent, adding indole, methyl active compound, aromatic aldehyde and the above catalyst, mixing uniformly for 6-10 hours, to obtain the corresponding indole derivative and seven-membered ring fused indole.

Preferably, after the reaction is completed, the catalyst is separated and recovered by an external magnetic field; the residue is concentrated under reduced pressure to remove the solvent, and the product is obtained by column chromatography separation.

In one embodiment according to the present invention, the molar ratio of indole, methyl reactive compound and aromatic aldehyde is 1:1:1.

In one embodiment according to the present invention, the molar amount of the catalyst is 0.01-0.03 times that of indole.

In one embodiment according to the present invention, the indole is selected from one of 1-H indole, 2-methyl indole or 5-methoxyindole; the methyl active compound is propyl A kind of in dinitrile, ethyl cyanoacetate; Described aromatic aldehyde is selected from formaldehyde, p-chlorobenzaldehyde, p-fluorobenzaldehyde, p-methylbenzaldehyde, p-methoxybenzaldehyde, p-nitrobenzaldehyde, One of p-trifluoromethylbenzaldehyde, 2-chlorobenzaldehyde, m-nitrobenzaldehyde or 3,4-dimethoxybenzaldehyde.

The present invention also provides indole derivatives and seven-membered ring fused indole prepared according to the synthetic method.

The beneficial effects of the present invention are:

1) after the reaction of the catalyst provided by the present invention, the catalyst can be separated and recovered by using a magnet;

2) The recovered catalyst is washed with ethanol, can be used for the next batch of reactions after vacuum drying, and the catalyst is reused 10 times, and the reaction yield does not decrease significantly.

3) The synthetic method of the indole derivative of the present invention and the seven-membered fused indole has high yield, simple operation, simple catalyst recovery, good reusability of the catalytic reaction system, mild reaction conditions, and has a good green industrialization prospect.

Detailed ways:

The preferred embodiments of the present invention are described in detail below, so that the advantages and characteristics of the present invention can be more easily understood by those skilled in the art, so that the protection scope of the present invention is more clearly defined.

The preparation of embodiment 1 catalyst

1) Preparation process of functionalized mesoporous polymeric ionic liquid:

Equimolar amounts of 2-bromoethyl acrylate and triethylenediamine were dissolved in methanol solution, under vacuum nitrogen protection, heated under reflux at 55°C for 24 hours, concentrated under reduced pressure, and dried under vacuum to obtain a pale yellow viscous liquid. The structure of the prepared ionic liquid was confirmed by ¹ H NMR. The molecular structure of the ionic liquid is shown in structural formula I:

2) The obtained ionic liquid is dissolved in methanol with Fe ₃ O ₄ modified by terminal alkene, divinylbenzene, initiator azobisisobutyronitrile, wherein, Fe ₃ O ₄ modified by terminal alkene, initiator, divinylbenzene and ionic liquid The molar ratio of the catalyst was 1:1:4:4, heated under vacuum at 70°C for 24 hours, and vacuum-dried at 70°C after the reaction was completed to obtain the final catalyst. As shown in structure II.

Example 2

Indole (1mmol), malononitrile (1mmol), p-chlorobenzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were successively added into 50mL single-neck flask, stirred at 60 DEG C for 6 hours, detected by TLC, and the raw materials basically disappeared, The catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography with a yield of 95%.

2-((4-chlorophenyl)(1H-indol-3-yl)methyl)malononitrile. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.33(s, 1H), 7.39(m, 6H) , 7.39 (m, 6H), 7.24 (m, 2H), 7.08 (m, 1H), 4.91 (d, J=4.8Hz, 1H), 4.44 (d, J=4.6Hz, 1H).

Example 3

Indole (1mmol), malononitrile (1mmol), p-fluorobenzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were successively added into 50mL single-necked flask, stirred at 60 DEG C for 6 hours, detected by TLC, and the raw materials basically disappeared, The catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography with a yield of 85%.

2-((4-fluorophenyl)(1H-indol-3-yl)methyl)malononitrile. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.34(s, 1H), 7.24(m, 3H) , 7.40 (m, 3H), 7.07 (m, 3H), 4.91 (d, J=4.6Hz, 1H), 4.43 (d, J=8.8Hz, 1H); ¹³ C NMR (100MHz, CDCl ₃ ) 165.26, 136.41, 130.19, 122.45, 119.91, 118.74, 115.66, 111.60.

Example 4

Indole (1mmol), malononitrile (1mmol), p-trifluoromethylbenzaldehyde (1mmol), 20mg catalyst, ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60 ° C for 7 hours, TLC detected, raw materials Basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was obtained by column chromatography separation, and the yield was 83%.

2-((1H-indol-3-yl)(4-(trifluoromethyl)phenyl)methyl)malononitrile. ¹ HNMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.35(s, 1H), 7.65(d, J=8.8Hz, 2H), 7.57(d, J=7.6Hz, 2H), 7.39(m, 2H), 7.25(m, 2H), 7.09(m, 1H), 4.99(d, J=8.4Hz, 1H), 4.47 (d, J=5.2Hz, 1H); ¹³ C NMR (100 MHz, CDCl ₃ ) 141.02, 136.31, 128.74, 126.21, 125.62, 123.35, 120.53, 118.52, 111.94, 43.78, 29.26.

Example 5

Indole (1mmol), malononitrile (1mmol), 2-chlorobenzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were successively added to the 50mL single-necked flask, stirred at 60°C for 8 hours, detected by TLC, and the raw materials basically disappeared. , the catalyst and the product are separated by external magnetic force, the obtained product is concentrated under reduced pressure, and finally the product is obtained by column chromatography, with a yield of 78%.

2-((2-chlorophenyl)(1H-indol-3-yl)methyl)malononitrile. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.38(s, 1H), 7.46(m, 2H) , 7.30(m, 1H), 7.26(m, 5H), 7.15(m, 1H), 5.53(d, J=8.6Hz, 1H), 4.51(d, J=4.4Hz, 1H); ¹³ C NMR( 100MHz, CDCl ₃ ) 136.21, 134.64, 133.59, 130.09, 127.77, 126.03, 123.20, 122.56, 120.36, 118.62, 112.15, 111.70, 111.11, 40.03, 27.78.

Example 6

Indole (1mmol), malononitrile (1mmol), p-methoxybenzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 6 hours, TLC detected, the raw materials were basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 83%.

2-((1H-indol-3-yl)(4-methoxyphenyl)methyl)malononitrile. ¹ H NMR(400MHz, CDCl ₃ , TMS)(ppm):δ 8.34(s,1H),7.34(m,4H) ,7.32(d,J＝4.8Hz,2H),7.24(s,1H),7.21(m,2H),4.85(d,J＝8.8Hz,1H),4.37(d,J＝4.4Hz,1H) , 3.77(s, 3H).

Example 7

Indole (1mmol), malononitrile (1mmol), 3,4-dimethoxybenzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were successively added to 50mL single-necked flask, stirred at 60°C for 6 hours, TLC After detection, the raw materials basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 88%.

2-((3,4-dimethoxyphenyl)(1H-indol-3-yl)methyl)malononitrile. ¹ H NMR(400 MHz, CDCl ₃ , TMS)(ppm): δ 8.40(s,1H),7.38(m ,2H),7.29(m,1H),7.23(m,1H), 7.07(m,2H),6.95(d,J=7.2Hz,1H),6.86(d,J=6.8Hz,1H),4.87 (d, J=4.4Hz, 1H), 4.45 (d, J=8.4Hz, 1H), 3.87 (s, 3H), 3.82 (s, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) 149.28, 136.32, 131.72, 129.50, 123.09, 122.05, 120.43, 118.77, 112.52, 111.46, 55.95, 43.95, 29.87.

Example 8

Indole (1mmol), ethyl cyanoacetate (1mmol), benzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were added successively in 50mL single-necked flask, stirred at 60 DEG C for 6 hours, TLC detected, the raw material basically disappeared, The catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography with a yield of 86%.

ethyl 2-cyano-3-(1H-indol-3-yl)-3-phenylpropanoate. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm): 8.34(d, J=18.4Hz, 1H), 7.40( m, 8H), 7.33 (m, 2H), 5.05 (m, 1H), 4.32 (d, J=8.8Hz, 1H), 4.31 (d, J=5.2Hz, 2H), 4.09 (m, 2H), 1.05(m, 1H).

Example 9

Indole (1mmol), ethyl cyanoacetate (1mmol), 2-chlorobenzaldehyde (1mmol), 20mg catalyst, ethanol (10mL) were added to 50mL single-neck flask successively, stirred at 60°C for 7 hours, TLC detected, raw material Basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 82%.

ethyl 3-(2-chlorophenyl)-2-cyano-3-(1H-indol-3-yl)propanoate. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.50(s, 1H), 7.59 (s, 1H), 7.24 (m, 4H), 7.05 (m, 4H), 5.66 (d, J=4.8Hz, 1H), 4.39 (d, J=8.4Hz, 1H), 4.10 (d, J= 9.2Hz, 2H), 1.04 (m, 3H).

Example 10

Indole (1mmol), ethyl cyanoacetate (1mmol), p-chlorobenzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 6 hours, TLC detected, the raw materials were basically disappeared, the catalyst and the product were separated by an external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 86%.

ethyl 3-(4-chlorophenyl)-2-cyano-3-(1H-indol-3-yl)propanoate. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.26(d, J＝19.2Hz ,1H),7.19(m,8H),6.95(m,1H),4.95(m,1H),4.08(d,J=8.4Hz,1H),4.01(m,2H),1.02(m,3H) .

Example 11

Indole (1mmol), ethyl cyanoacetate (1mmol), p-fluorobenzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were added successively in a 50mL single-neck flask, stirred at 60°C for 6 hours, TLC detected, the raw materials were basically disappeared, the catalyst and the product were separated by an external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 91%.

Ethyl 2-cyano-3-(4-fluorophenyl)-3-(1H-indol-3-yl)propanoate. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.26 (d, J=19.2Hz ,1H),7.37(m,4H),7.14(m,4H),5.07(d,J＝7.6Hz,1H),4.30(d,J＝6.4Hz,1H),4.12(m,2H),1.04 (m,3H); ¹³ C NMR (100 MHz, CDCl ₃ ) 165.18, 138.32, 136.17, 133.59, 129.21, 126.46, 122.46, 119.89, 118.84, 116.22, 112.73, 111.48, 63.14, 44.92, 42.63.

Example 12

2-methylindole (1mmol), malononitrile (1mmol), 2-chlorobenzaldehyde (1mmol), 20mg catalyst and ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 10 hours, and detected by TLC , the raw materials basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was obtained by column chromatography separation, and the yield was 90%.

2-((2-chlorophenyl)(2-methyl-1H-indol-3-yl)methyl)malononitrile. ¹ HNMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.02(s, 1H), 7.71(m ,1H),7.42(m,3H),7.29(m,2H),7.12(m,1H),7.03(m,1H),5.29(d,J＝11.6Hz,1H),2.54(s,3H) .

Example 13

2-methoxyindole (1mmol), malononitrile (1mmol), benzaldehyde (1mmol), 20mg catalyst and ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 10 hours, detected by TLC, and the raw materials were Basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 92%.

2-((5-methoxy-1H-indol-3-yl)(phenyl)methyl)malononitrile. ¹ H NMR(400MHz, CDCl ₃ , TMS)(ppm):δ 8.19(s,1H),7.45(m, 2H), 7.36(m, 4H), 7.29(d, J=8.4Hz, 1H), 6.87(m, 1H), 6.68(s, 1H), 4.88(d, J=4.8Hz, 1H), 4.44( d, J = 8.4 Hz, 1H), 3.72 (s, 3H).

Example 14

4-hydroxyindole (1mmol), malononitrile (1mmol), benzaldehyde (1mmol), 20mg catalyst and ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 10 hours, detected by TLC, and the raw materials basically disappeared. , the catalyst and the product are separated by external magnetic force, the obtained product is concentrated under reduced pressure, and finally the product is separated by column chromatography, and the yield is 90%.

(E)-2-amino-4-phenyl-4,6-dihydrooxepino[4,3,2-cd]indole-3-carbonitrile. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm): δ 8.26( s, 1H), 7.29(m, 2H), 7.21(m, 4H), 7.08(d, J=9.6Hz, 1H), 6.74(d, J=8.8Hz, 1H), 6.65(m, 1H), 4.84(s, 1H), 4.66(s, 2H).

Example 15

4-hydroxyindole (1mmol), malononitrile (1mmol), p-nitrobenzaldehyde (1mmol), 20mg catalyzer and ethanol (10mL) were successively added into 50mL single-necked flask, stirred at 60°C for 510 hours, TLC detected, The raw material basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 88%.

(E)-2-amino-4-(4-nitrophenyl)-4,6-dihydrooxepino[4,3,2-cd]indole-3-carbon itrile. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm ): δ 8.36(s, 1H), 8.16(d, J=9.2Hz, 2H), 7.38(d, J=11.Hz, 2H), 7.25(m, 1H), 7.11(d, J=9.6Hz) , 1H), 6.66 (m, 2H), 4.97 (s, 1H), 4.79 (s, 2H).

Example 16

4-hydroxyindole (1mmol), malononitrile (1mmol), 2-chlorobenzaldehyde (1mmol), 20mg catalyzer and ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 5 hours, and detected by TLC. The raw material basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 91%.

(E)-2-amino-4-(2-chlorophenyl)-4,6-dihydrooxepino[4,3,2-cd]indole-3-carbo nitrile. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm ): δ 8.36(s, 1H), 7.36(d, j=9.6Hz, 1H), 7.20(m, 1H), 7.16(m, 3H), 7.06(d, 9.2Hz, 1H), 6.78(d, 9.6Hz, 1H), 6.64(m, 1H), 5.51(s, 1H), 4.72(s, 2H).

Example 17

4-hydroxyindole (1mmol), malononitrile (1mmol), p-trifluoromethylbenzaldehyde (1mmol), 20mg catalyzer, ethanol (10mL) were successively added to a 50mL single-necked flask, stirred at 60° C. for 5 hours, and TLC Detection, the raw material basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was obtained by column chromatography separation, and the yield was 70%.

(E)-2-amino-4-(4-(trifluoromethyl)phenyl)-4,6-dihydrooxepino[4,3,2-cd]ind ole-3-carbonitrile. ¹ H NMR (400MHz, CDCl ₃ , TMS )(ppm): δ 8.35(d,J=19.6Hz,1H),7.55(d,J=8.0Hz,2H),7.33(d,J=7.6Hz,2H),7.23(d,J=4.0Hz , 1H), 7.10 (d, J=8.0Hz, 1H), 6.68 (m, 2H), 4.91 (d, J=2.0Hz, 1H), 4.75 (d, J=8.0Hz, 2H).

Example 18

4-Hydroxyindole (1mmol), malononitrile (1mmol), p-fluorobenzaldehyde (1mmol), 20mg catalyst, ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 6 hours, TLC detected, raw materials Basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 81%.

(E)-2-amino-4-(4-fluorophenyl)-4,6-dihydrooxepino[4,3,2-cd]indole-3-carbo nitrile. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm ): δ 8.29(s, 1H), 7.17-7.23(m, 3H), 7.09(d, J=7.7Hz, 1H), 6.98(m, 2H), 6.70(d, J=8.4Hz, 1H), 6.65(m, 1H), 4.84(s, 1H), 4.68(s, 2H); ¹³ C NMR (100 MHz, CDCl ₃ ) 159.16, 141.29, 136.28, 129.55, 124.55, 122.94, 120.18, 116.86, 115.62, 115.41, 111.96, 108.50, 99.12, 58.51, 40.30, 18.45.

Example 19

4-hydroxyindole (1mmol), malononitrile (1mmol), m-nitrobenzaldehyde (1mmol), 20mg catalyzer and ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 6 hours, and detected by TLC. The raw material basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 85%.

(E)-2-amino-4-(3-nitrophenyl)-4,6-dihydrooxepino[4,3,2-cd]indole-3-carbon itrile. ¹ H NMR (400MHz, CDCl ₃ , TMS) (ppm ): δ 8.33(s,1H),8.10(m,1H),8.05(m,2H),7.63(d,J=7.6,2H),7.49(m,1H),7.24(d,J=2.8Hz , 1H), 7.11(d, J=9.2Hz, 1H), 6.67(m, 2H), 4.99(s, 1H), 4.79(s, 2H); ¹³ C NMR (100MHz, CDCl ₃ ) 159.59, 148.60, 147.68, 136.52, 134.22, 129.67, 124.84, 122.95, 122.55, 122.26, 117.02, 110.66, 108.83, 99.22, 58.49, 40.91, 29.71, 18.43.

Example 20

4-hydroxyindole (1mmol), malononitrile (1mmol), p-methylbenzaldehyde (1mmol), 20mg catalyst and ethanol (10mL) were successively added to a 50mL single-neck flask, stirred at 60°C for 7 hours, detected by TLC, The raw material basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 85%.

(E)-2-amino-4-p-tolyl-4,6-dihydrooxepino[4,3,2-cd]indole-3-carbonitrile. ¹ H NMR (400 MHz, CDCl ₃ , TMS) (ppm): δ 8.30(s, 1H), 7.18(d, J=4.4Hz, 1H), 7.09 (s, 4H), 7.05(m, 1H), 6.72(d, J=13.2Hz, 1H), 6.63(d, J =4.4Hz, 1H), 4.79(s, 1H), 4.64(s, 2H), 2.29(s, 3H).

Example 21

4-hydroxyindole (1mmol), malononitrile (1mmol), 3,4-dimethoxybenzaldehyde (1mmol), 20mg catalyst and ethanol (10mL) were successively added to a 50mL single-neck flask, and stirred at 60°C for 8 Within hours, TLC detection showed that the raw materials basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was separated by column chromatography, and the yield was 76%.

(E)-2-amino-4-(3,4-dimethoxyphenyl)-4,6-dihydrooxepino[4,3,2-cd]indole-3-carbonitrile. ¹ H NMR (400MHz, CDCl ₃ , TMS)( ppm): δ 8.31(s, 1H), 7.21(d, J=4.8Hz, 1H), 7.08(d, J=9.6Hz, 1H), 6.78(m, 4H), 6.65(s, H), 4.80 (s, 1H), 4.66 (s, 2H), 3.84 (s, 3H), 3.8 (s, 3H).

Example 22

With indole (1mmol), malononitrile (1mmol), p-chlorobenzaldehyde (1mmol) in embodiment 1, the catalyst and ethanol (10mL) after 50 ℃ of vacuum drying with an external magnet recovery 50 ℃ of vacuum dryings were successively added to a 50mL single-necked flask, Stir at 60°C for 6 hours, TLC detection, the raw materials basically disappeared, the catalyst and the product were separated by external magnetic force, the obtained product was concentrated under reduced pressure, and finally the product was obtained by column chromatography separation with a yield of 95%. The catalyst was reused 10 times, and no obvious decrease in yield was found, as shown in Table 1.

Table 1 Catalyst performance test table

The above-mentioned summary of the invention and the specific embodiments are intended to prove the practical application of the technical solutions provided by the present invention, and should not be construed as limiting the protection scope of the present invention. Various modifications, equivalent replacements, or improvements may be made by those skilled in the art within the spirit and principles of the present invention. The protection scope of the present invention is subject to the appended claims.

Claims (7)

1. The preparation method of the magnetic mesoporous polymerization ionic liquid catalyst is characterized by comprising the following steps:

1) dissolving equimolar amounts of 2-bromoethyl acrylate and triethylene diamine in a methanol solution, heating and refluxing for reaction for a certain time at 50-60 ℃ under the protection of vacuum nitrogen, and carrying out reduced pressure concentration and vacuum drying to obtain a light yellow viscous ionic liquid;

2) mixing the ionic liquid obtained in the step 1) with terminal alkene modified Fe₃O₄Dissolving divinylbenzene and an initiator in methanol, heating and refluxing at 60-80 ℃ in vacuum until the reaction is complete, and drying in vacuum after the reaction is finished to obtain the final catalyst;

the molecular structure of the ionic liquid is shown as a structural formula I;

2. the method of claim 1, wherein the terminal alkene-modified Fe in step 2)₃O₄The molar ratio of the initiator to the divinylbenzene to the ionic liquid is 1: 1: 4: 4.

3. a magnetic mesoporous polymeric ionic liquid catalyst, characterized in that the catalyst is prepared according to the preparation method of claim 1 or 2.

4. The catalyst of claim 3, wherein the molecular structure of the catalyst is represented by structural formula II;

5. a method for synthesizing indole derivatives, which comprises the following steps:

taking ethanol as a solvent, adding indole, a methyl active compound, aromatic aldehyde and the catalyst of claim 3 or 4, mixing uniformly and reacting for 6-10 hours to obtain a corresponding indole derivative;

the indole is selected from one of 1-H indole, 2-methylindole or 5-methoxyindole; the methyl active compound is one of malononitrile and ethyl cyanoacetate; the aromatic aldehyde is selected from one of formaldehyde, p-chlorobenzaldehyde, p-fluorobenzaldehyde, p-methylbenzaldehyde, p-methoxybenzaldehyde, p-nitrobenzaldehyde, p-trifluoromethylbenzaldehyde, 2-chlorobenzaldehyde, m-nitrobenzaldehyde or 3, 4-dimethoxybenzaldehyde.

6. The method of synthesis according to claim 5,

the mol ratio of the indole and methyl active compounds to the aromatic aldehyde is 1: 1: 1.

7. the synthesis method of claim 5, wherein the molar amount of the catalyst is 0.01-0.03 times that of indole.