A process for the preparation of 3-benzylamino-2-butenenitrile

Abstract

This invention discloses a method for preparing 3-benzylamino-2-butenonitrile: A cation exchange membrane separates the anode and cathode chambers of an electrolytic cell; a graphite electrode is used as the anode and a metal electrode as the cathode; the anolyte is a 0.1–1.0 mol / L acetonitrile solution of a quaternary ammonium salt; the cathode electrolyte is an acetonitrile solution of a quaternary ammonium salt and benzylamine, wherein the concentration of the quaternary ammonium salt is 0.05–0.5 mol / L and the concentration of the benzylamine is 0.05–0.5 mol / L; N2 is passed into the cathode chamber at 0–35°C until saturation, at a rate of 12–18 mA / cm². 2 The method involves constant current density electrolysis; the charge per mole of benzylamine is 1.0–2.5 F; after electrolysis, the liquid in the cathode chamber is evaporated under reduced pressure to remove acetonitrile; 0.5–1 volume of saturated sodium bicarbonate solution is added, followed by extraction with diethyl ether, drying, and filtration. The filtrate is then purified of diethyl ether to obtain 3-benzylamino-2-butenonitrile. This invention is simple, economical, and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, and particularly relates to a method for preparing 3-benzylamino-2-butenonitrile. Background Technology

[0002] β-Aminonitriles include 3-amino-2-butenonitrile and its N-substituted derivatives. β-Aminonitriles exhibit excellent reactivity and are widely used as important synthons in the synthesis of various heterocyclic compounds, especially nitrogen-containing heterocycles. Examples include the synthesis of substituted pyridines, dihydropyridines, and quinolines. Currently, there are two main methods for preparing β-aminonitriles:

[0003] 1) Acetonitrile dimerization under the action of metallic sodium

[0004] In the early days, the most common method for synthesizing β-aminonitriles was the dimerization of acetonitrile with sodium in organic solvents. This route could yield β-aminocrotonitrile in quantitative yields, but it also produced the highly toxic substance NaCN in the reaction.

[0005]

[0006] 2) Reaction of benzoylacetonitrile with amines

[0007] In 2008, Malkov et al. reported the preparation of β-enamine nitrile by stirring a mixture of benzoylacetonitrile, aniline, and acetic acid in an oil bath at 80°C under argon protection for 6 hours (Malkov, AVChem. Eur. J. 2008, 14, 8082-8085). Benzoylacetonitrile was prepared by reacting ethyl benzoate with acetonitrile. This route involves two steps and is relatively cumbersome. Summary of the Invention

[0008] The purpose of this invention is to provide a simple and non-cyanide-by-product method for preparing 3-benzylamino-2-butenonitrile.

[0009] The technical solution of this invention is as follows:

[0010] A method for preparing 3-benzylamino-2-butenonitrile includes the following steps:

[0011] Step 1, Electrolysis Preparation:

[0012] The anode and cathode chambers of the electrolytic cell are separated by a cation exchange membrane; a graphite electrode is used as the anode, and a metal electrode is used as the cathode; the anolyte is an acetonitrile solution of a quaternary ammonium salt at a concentration of 0.1–1.0 mol / L; the cathode electrolyte is an acetonitrile solution of a quaternary ammonium salt and benzylamine, wherein the concentration of the quaternary ammonium salt is 0.05–0.5 mol / L, and the concentration of benzylamine is 0.05–0.5 mol / L; the molar ratio of the quaternary ammonium salt in the cathode electrolyte and the anolyte is 1:2.

[0013] Step 2, Electrolysis:

[0014] At atmospheric pressure and 0–35°C, N2 is introduced into the cathode chamber until saturation, at a rate of 12–18 mA / cm². 2 Electrolysis is performed at a constant current density; and the charge per mole of benzylamine is 1.0–2.5 F, where F is the Faraday constant.

[0015] Step 3, Post-processing:

[0016] After electrolysis, the liquid in the cathode chamber is removed and the acetonitrile is removed by rotary evaporation under reduced pressure. Saturated sodium bicarbonate solution is added, with the amount added being 0.5-1 times the volume of the liquid removed from the cathode chamber. Then, ether is added for extraction. The resulting ether layer is dried with anhydrous magnesium sulfate, filtered, and the filtrate is subjected to a second rotary evaporation to remove the ether, thus obtaining 3-benzylamino-2-butenonitrile.

[0017] Preferably, the quaternary ammonium salt is one of tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetraethylammonium tetrafluoroborate, tetra-n-butylammonium iodide, and tetraethylammonium perchlorate.

[0018] Preferably, the cation exchange membrane is an FKS-50 cation exchange membrane.

[0019] Preferably, the cathode is made of copper, nickel, titanium, stainless steel, platinum, or silver.

[0020] Preferably, the constant current density in step two is 13.5 mA / cm². 2 .

[0021] Preferably, the electrolysis temperature in step two is 15°C.

[0022] Preferably, the charge per mole of benzylamine in step two is 2.2 F.

[0023] Preferably, the molar ratio of the quaternary ammonium salt in the cathode electrolyte and the anolyte in step one is 1:2.

[0024] The beneficial effects of this invention are as follows:

[0025] The method for preparing 3-benzylamino-2-butenonitrile of the present invention is simple, does not produce toxic and harmful byproducts such as cyanide, and is economical and environmentally friendly. Attached Figure Description

[0026] Figure 1 The 3-benzylamino-2-butenonitrile prepared in Example 1 1 H-NMR spectrum.

[0027] Figure 2 The infrared spectrum of 3-benzylamino-2-butenonitrile prepared in Example 1 is shown.

[0028] Figure 3 The 3-benzylamino-2-butenonitrile prepared in Example 1 13 C-NMR spectrum.

[0029] Figure 4 The image shows the liquid phase mass spectrum of 3-benzylamino-2-butenonitrile prepared in Example 1.

[0030] Figure 5 The image shows the liquid chromatogram of the product obtained in Comparative Example 1.

[0031] Figure 6 The image shows the liquid chromatogram of the product obtained in Comparative Example 2. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the embodiments.

[0033] Example 1

[0034] 1. Preparation of 3-benzylamino-2-butenonitrile, the method is as follows:

[0035] (1) Electrolysis preparation:

[0036] The anode and cathode chambers of the electrolytic cell are separated using an FKS-50 cation exchange membrane. An anolyte is added to the anode chamber, and a catholyte is added to the cathode chamber, with the same volume for both. The anolyte is a 1.0 mol / L tetraethylammonium chloride acetonitrile solution; the catholyte is an acetonitrile solution of tetraethylammonium chloride and benzylamine, wherein the concentration of tetraethylammonium chloride is 0.5 mol / L and the concentration of benzylamine is 0.3 mol / L.

[0037] (2) Electrolysis:

[0038] At 20°C and normal pressure, N2 was introduced into the cathode chamber until saturation, using Cu as the cathode and graphite as the anode, and then the current was increased to 13.5 mA / cm². 2 Constant current electrolysis was performed using a constant current density, with a charge of 2.0 F per mole of benzylamine.

[0039] (3) Post-processing:

[0040] After electrolysis, the liquid in the cathode chamber was removed and the acetonitrile was removed by rotary evaporation under reduced pressure. Saturated sodium bicarbonate solution was added, with the amount added being 1.0 times the volume of the liquid removed from the cathode chamber. Then, ether was added and extracted three times. The ether layers were combined, and the resulting ether layer liquid was dried with anhydrous magnesium sulfate for 2 hours. After filtration, the filtrate was subjected to a second rotary evaporation to remove the ether, yielding the product 3-benzylamino-2-butenonitrile.

[0041] 2. Product Testing

[0042] (1) Product process 1 ¹H-NMR (600MHz, deuterated chloroform d-CDCH₃) analysis yielded the following values: δppm 2.13 (s, 3H, -CH₃), 3.84 (s, 1H, =CH), 4.13 (d, J = 5.09Hz, 2H, PhCH₂-), 4.74 (brs, 1H, -NH₃-), 7.26 (d, J = 7.27Hz, 2H), 7.31 (d, J = 7.27Hz, 1H), 7.34-7.37 (m, 2H). Figure 1 As shown.

[0043] (2) The product was subjected to infrared spectroscopy testing using a Nicolet iS20 Fourier transform infrared spectrometer manufactured by Thermo Nicolet. Figure 2 List the infrared spectrum of this compound, IR (KBr, cm⁻¹). -1 ):3430,3312,3088,2196,1631,1597,1350.

[0044] (3) Product processing 13 C-NMR (deuterated chloroform d-CDCH3) analysis yielded δppm values ​​of 20.22, 47.84, 61.62, 121.73, 127.65, 128.00, 128.94, 136.44, and 159.87. Figure 3 As shown.

[0045] (4) The molecular weight of the product measured by liquid chromatography-mass spectrometry (LC-MS) was 172.8. Figure 4 As shown, the peak of 3-benzylamino-2-butenonitrile appears at a retention time of 4.95 min on the liquid chromatogram.

[0046] (5) Yield testing:

[0047] The synthesized product was analyzed by high performance liquid chromatography, and the yield of 3-benzylamino-2-butenonitrile was found to be 30%.

[0048] Example 2

[0049] 1. Preparation of 3-benzylamino-2-butenonitrile, the method is as follows:

[0050] (1) Electrolysis preparation:

[0051] The anode and cathode chambers of the electrolytic cell are separated using an FKS-50 cation exchange membrane. An anolyte is added to the anode chamber, and a catholyte is added to the cathode chamber, with the same volume for both. The anolyte is a 0.5 mol / L tetraethylammonium chloride acetonitrile solution; the catholyte is an acetonitrile solution of tetraethylammonium chloride and benzylamine, wherein the concentration of tetraethylammonium chloride is 0.25 mol / L and the concentration of benzylamine is 0.5 mol / L.

[0052] (2) Electrolysis:

[0053] At 15°C and normal pressure, N2 was introduced into the cathode chamber until saturation, using Cu as the cathode and graphite as the anode, and then the current was increased to 12.0 mA / cm². 2 Constant current electrolysis was performed at a constant current density, with a charge of 2.2 F per mole of benzylamine.

[0054] (3) Post-processing:

[0055] After electrolysis, the liquid in the cathode chamber was removed and the acetonitrile was removed by rotary evaporation under reduced pressure. Saturated sodium bicarbonate solution was added, with the amount added being 0.5 times the volume of the liquid removed from the cathode chamber. Then, ether was added and extracted three times. The ether layers were combined, and the resulting ether layer liquid was dried with anhydrous magnesium sulfate for 2 hours. After filtration, the filtrate was subjected to a second rotary evaporation to remove the ether, thus obtaining 3-benzylamino-2-butenonitrile.

[0056] 2. Product Testing

[0057] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0058] (2) Yield testing:

[0059] The yield of 3-benzylamino-2-butenonitrile was determined to be 17% using high performance liquid chromatography (HPLC).

[0060] Example 3

[0061] 1. Preparation of 3-benzylamino-2-butenonitrile, the method is as follows:

[0062] (1) Electrolysis preparation:

[0063] The anode and cathode chambers of the electrolytic cell are separated using an FKS-50 cation exchange membrane. An anolyte is added to the anode chamber, and a catholyte is added to the cathode chamber, with the same volume for both. The anolyte is a 0.1 mol / L tetraethylammonium chloride acetonitrile solution; the catholyte is an acetonitrile solution of tetraethylammonium chloride and benzylamine, wherein the concentration of tetraethylammonium chloride is 0.05 mol / L and the concentration of benzylamine is 0.1 mol / L.

[0064] (2) Electrolysis:

[0065] At 0°C and normal pressure, N2 is introduced into the cathode chamber until saturation, using Cu as the cathode and graphite as the anode, and then the current is increased to 15.0 mA / cm². 2 Constant current electrolysis was performed using a constant current density, with a charge of 2.5 F per mole of benzylamine.

[0066] (3) Post-processing:

[0067] After electrolysis, the liquid in the cathode chamber was removed and the acetonitrile was removed by rotary evaporation under reduced pressure. Saturated sodium bicarbonate solution was added, with the amount added being 0.8 times the volume of the liquid removed from the cathode chamber. Then, ether was added and extracted three times. The ether layers were combined, and the resulting ether layer liquid was dried with anhydrous magnesium sulfate for 2 hours. After filtration, the filtrate was subjected to a second rotary evaporation to remove the ether, thus obtaining 3-benzylamino-2-butenonitrile.

[0068] 2. Product Testing

[0069] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0070] (2) Yield testing:

[0071] The yield of 3-benzylamino-2-butenonitrile was determined to be 24% using high performance liquid chromatography (HPLC).

[0072] Example 4

[0073] 1. Preparation of 3-benzylamino-2-butenonitrile, the method is as follows:

[0074] (1) Electrolysis preparation:

[0075] The anode and cathode chambers of the electrolytic cell are separated using an FKS-50 cation exchange membrane. An anolyte is added to the anode chamber, and a catholyte is added to the cathode chamber, with the same volume for both. The anolyte is a 0.80 mol / L tetraethylammonium chloride acetonitrile solution; the catholyte is an acetonitrile solution of tetraethylammonium chloride and benzylamine, wherein the concentration of tetraethylammonium chloride is 0.40 mol / L and the concentration of benzylamine is 0.20 mol / L.

[0076] (2) Electrolysis:

[0077] At 35°C and normal pressure, N2 was introduced into the cathode chamber until saturation, using Cu as the cathode and graphite as the anode, and then the current was increased to 16.5 mA / cm². 2 Constant current electrolysis was performed using a constant current density, with a charge of 1.0 F per mole of benzylamine.

[0078] (3) Post-processing:

[0079] After electrolysis, the liquid in the cathode chamber was removed and the acetonitrile was removed by rotary evaporation under reduced pressure. Saturated sodium bicarbonate solution was added, with the amount added being 1.0 times the volume of the liquid removed from the cathode chamber. Then, ether was added and extracted three times. The ether layers were combined, and the resulting ether layer liquid was dried with anhydrous magnesium sulfate for 2 hours. After filtration, the filtrate was subjected to a second rotary evaporation to remove the ether, thus obtaining 3-benzylamino-2-butenonitrile.

[0080] 2. Product Testing

[0081] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0082] (2) Yield testing:

[0083] The yield of 3-benzylamino-2-butenonitrile was determined to be 13% using high performance liquid chromatography (HPLC).

[0084] Example 5

[0085] 1. Preparation of 3-benzylamino-2-butenonitrile, the method is as follows:

[0086] (1) Electrolysis preparation:

[0087] The anode and cathode chambers of the electrolytic cell are separated using an FKS-50 cation exchange membrane. An anolyte is added to the anode chamber, and a catholyte is added to the cathode chamber, with the same volume for both. The anolyte is a 1.0 mol / L tetraethylammonium chloride acetonitrile solution; the catholyte is an acetonitrile solution of tetraethylammonium chloride and benzylamine, wherein the concentration of tetraethylammonium chloride is 0.5 mol / L and the concentration of benzylamine is 0.05 mol / L.

[0088] (2) Electrolysis:

[0089] At 10°C and normal pressure, N2 was introduced into the cathode chamber until saturation, using Cu as the cathode and graphite as the anode, and then the current was increased to 18.0 mA / cm². 2 Constant current electrolysis was performed at a constant current density, with a charge of 2.2 F per mole of benzylamine.

[0090] (3) Post-processing:

[0091] After electrolysis, the liquid in the cathode chamber was removed and the acetonitrile was removed by rotary evaporation under reduced pressure. Saturated sodium bicarbonate solution was added, with the amount added being 1.0 times the volume of the liquid removed from the cathode chamber. Then, ether was added and extracted three times. The ether layers were combined, and the resulting ether layer liquid was dried with anhydrous magnesium sulfate for 2 hours. After filtration, the filtrate was subjected to a second rotary evaporation to remove the ether, thus obtaining 3-benzylamino-2-butenonitrile.

[0092] 2. Product Testing

[0093] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0094] (2) Yield testing:

[0095] The yield of 3-benzylamino-2-butenonitrile was determined to be 18% using high performance liquid chromatography (HPLC).

[0096] Example 6

[0097] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment using the same method as in Example 1, except that Ag was used as the cathode electrode.

[0098] 2. Product Testing

[0099] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0100] (2) Yield testing:

[0101] The yield of 3-benzylamino-2-butenonitrile was determined to be 16% using high performance liquid chromatography (HPLC).

[0102] Example 7

[0103] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment using the same method as in Example 1, except that Ni was used as the cathode electrode.

[0104] 2. Product Testing

[0105] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0106] (2) Yield testing:

[0107] The yield of 3-benzylamino-2-butenonitrile was determined to be 13% using high performance liquid chromatography (HPLC).

[0108] Example 8

[0109] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment in exactly the same way as in Example 1, except that 304 stainless steel was used as the cathode electrode.

[0110] 2. Product Testing

[0111] (1) The product was subjected to 1H-NMR, infrared spectroscopy, 13C-NMR and liquid chromatography-mass spectrometry using the same method as in Example 1. The product was found to be 3-benzylamino-2-butenonitrile.

[0112] (2) Yield testing:

[0113] The yield of 3-benzylamino-2-butenonitrile was determined to be 15% by high performance liquid chromatography (HPLC).

[0114] Example 9

[0115] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment in exactly the same way as in Example 1, except that a platinum electrode was used as the cathode electrode.

[0116] 2. Product Testing

[0117] (1) The product was subjected to 1H-NMR, infrared spectroscopy, 13C-NMR and liquid chromatography-mass spectrometry using the same method as in Example 1. The product was found to be 3-benzylamino-2-butenonitrile.

[0118] (2) Yield testing:

[0119] The yield of 3-benzylamino-2-butenonitrile was determined to be 26% using high performance liquid chromatography (HPLC).

[0120] Example 10

[0121] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment in exactly the same way as in Example 1, except that Ti was used as the cathode electrode.

[0122] 2. Product Testing

[0123] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0124] (2) Yield testing:

[0125] The yield of 3-benzylamino-2-butenonitrile was determined to be 10% by high performance liquid chromatography (HPLC).

[0126] Example 11

[0127] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment using the same method as in Example 1, except that tetraethylammonium bromide was used instead of tetraethylammonium chloride.

[0128] 2. Product Testing

[0129] (1) The product was subjected to 1H-NMR, infrared spectroscopy, 13C-NMR and liquid chromatography-mass spectrometry using the same method as in Example 1. The product was found to be 3-benzylamino-2-butenonitrile.

[0130] (2) Yield testing:

[0131] The yield of 3-benzylamino-2-butenonitrile was determined to be 14% using high performance liquid chromatography (HPLC).

[0132] Example 12

[0133] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment in exactly the same way as in Example 1, except that tetraethylammonium iodide was used instead of tetraethylammonium chloride.

[0134] 2. Product Testing

[0135] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0136] (2) Yield testing:

[0137] The yield of 3-benzylamino-2-butenonitrile was determined to be 18% using high performance liquid chromatography (HPLC).

[0138] Example 13

[0139] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment in exactly the same way as in Example 1, except that tetraethylammonium tetrafluoroborate was used instead of tetraethylammonium chloride.

[0140] 2. Product Testing

[0141] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0142] (2) Yield testing:

[0143] The yield of 3-benzylamino-2-butenonitrile was determined to be 51% using high performance liquid chromatography (HPLC).

[0144] Example 14

[0145] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment in exactly the same way as in Example 1, except that tetra-n-butylammonium iodide was used instead of tetraethylammonium chloride.

[0146] 2. Product Testing

[0147] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0148] (2) Yield testing:

[0149] The yield of 3-benzylamino-2-butenonitrile was determined to be 20% using high performance liquid chromatography (HPLC).

[0150] Example 15

[0151] 1. 3-Benzylamino-2-butenonitrile was prepared by electrolytic preparation, electrolysis and post-treatment using the same method as in Example 1, except that tetraethylammonium perchlorate was used instead of tetraethylammonium chloride.

[0152] 2. Product Testing

[0153] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0154] (2) Yield testing:

[0155] The yield of 3-benzylamino-2-butenonitrile was determined to be 10% by high performance liquid chromatography (HPLC).

[0156] Example 16

[0157] 1. Preparation of 3-benzylamino-2-butenonitrile, the method is as follows:

[0158] (1) An FKS-50 cation exchange membrane is used to separate the anode and cathode chambers of the electrolytic cell. An anolyte is added to the anode chamber, and a catholyte is added to the cathode chamber. The volumes of the anolyte and the catholyte are the same. The anolyte is a 0.5 mol / L tetraethylammonium chloride acetonitrile solution; the catholyte is a tetraethylammonium chloride and benzylamine acetonitrile solution, wherein the concentration of tetraethylammonium chloride is 0.5 mol / L and the concentration of benzylamine is 0.3 mol / L.

[0159] Electrolysis preparation, electrolysis, and post-treatment were performed using the exact same method as in Example 1.

[0160] 2. Product Testing

[0161] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry analysis revealed that the product was 3-benzylamino-2-butenonitrile.

[0162] (2) Yield testing:

[0163] The yield of 3-benzylamino-2-butenonitrile was determined to be 20% using high performance liquid chromatography (HPLC).

[0164] Comparative Example 1

[0165] Electrolysis preparation and electrolysis were performed using the exact same method as in Example 1, with the only difference being the post-processing steps, which are as follows:

[0166] After electrolysis, the liquid in the cathode chamber was removed and acetonitrile was removed by rotary evaporation under reduced pressure. 0.2 mol / L hydrochloric acid was added, with the amount added being 1.0 times the volume of the liquid removed from the cathode chamber. Then, diethyl ether was added and extracted three times. The ether layers were combined, and the resulting ether layer liquid was dried with anhydrous magnesium sulfate for 2 hours. After filtration, the filtrate was subjected to a second rotary evaporation to remove the diethyl ether and obtain the product.

[0167] 2. Product Testing

[0168] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry tests showed that the product did not contain 3-benzylamino-2-butenonitrile. Figure 5 The liquid chromatogram of the product obtained in this comparative example is shown below. Figure 5 As shown, no peak of 3-benzylamino-2-butenonitrile was observed at the retention time of 4.95 min in the liquid chromatogram; while the liquid chromatogram of the product prepared in Example 1 showed... Figure 4 In the liquid chromatogram, the peak of 3-benzylamino-2-butenonitrile appeared at a retention time of 4.95 min.

[0169] Comparative Example 2

[0170] 1. Preparation

[0171] (1) Preparation:

[0172] The anode and cathode chambers of the electrolytic cell are separated using an FKS-50 cation exchange membrane. An anolyte is added to the anode chamber, and a catholyte is added to the cathode chamber, with the same volume for both. The anolyte is a 1.0 mol / L tetraethylammonium chloride acetonitrile solution; the catholyte is an acetonitrile solution of tetraethylammonium chloride and benzylamine, wherein the concentration of tetraethylammonium chloride is 0.5 mol / L and the concentration of benzylamine is 0.3 mol / L.

[0173] (2) Stirring and mixing:

[0174] At 20°C and normal pressure, N2 was introduced into the cathode chamber until saturation, and the cathode electrolyte was thoroughly stirred and mixed for 10 hours using a stirrer.

[0175] (3) Post-processing:

[0176] The liquid in the cathode chamber was removed and acetonitrile was removed by rotary evaporation under reduced pressure. Saturated sodium bicarbonate solution was added, with the amount added being 1.0 times the volume of the liquid removed from the cathode chamber. Then, ether was added and extracted three times. The ether layers were combined, and the resulting ether layer liquid was dried with anhydrous magnesium sulfate for 2 hours. After filtration, the filtrate was subjected to a second rotary evaporation to remove the ether and obtain the product.

[0177] 2. Product Testing

[0178] (1) The product was processed using the same method as in Example 1. 1 H-NMR testing, infrared spectroscopy testing 13 C-NMR and liquid chromatography-mass spectrometry tests showed that the product did not contain 3-benzylamino-2-butenonitrile. Figure 6 This is the liquid chromatogram of the product obtained in this comparative example. No peak of 3-benzylamino-2-butenonitrile was observed at the retention time of 4.95 min in this chromatogram.

[0179] It should be noted that the descriptions of these embodiments are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. In addition, the above are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

Claims

1. A method for preparing 3-benzylamino-2-butenonitrile, characterized in that, Includes the following steps: Step 1, Electrolysis Preparation: The anode chamber and cathode chamber of the electrolytic cell are separated by a cation exchange membrane; A graphite electrode is used as the anode and a metal electrode as the cathode. The anode electrolyte is an acetonitrile solution of 0.1–1.0 mol / L quaternary ammonium salt; the cathode electrolyte is an acetonitrile solution of quaternary ammonium salt and benzylamine, wherein the concentration of the quaternary ammonium salt is 0.05–0.5 mol / L and the concentration of the benzylamine is 0.05–0.5 mol / L. The quaternary ammonium salt is one of tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetraethylammonium tetrafluoroborate, tetra-n-butylammonium iodide, and tetraethylammonium perchlorate. Step 2, Electrolysis: Under normal pressure and at 0–35°C, N2 is introduced into the cathode chamber until saturation, at a rate of 12.0–18.0 mA / cm². 2 Electrolysis is performed at a constant current density; and the charge per mole of benzylamine is 1.0–2.5 F, where F is the Faraday constant. Step 3, Post-processing: After electrolysis, the liquid in the cathode chamber is removed and the acetonitrile is removed by rotary evaporation under reduced pressure. Add saturated sodium bicarbonate solution, the amount of which is 0.5-1 times the volume of liquid taken out from the cathode chamber; then add diethyl ether for extraction, dry the resulting ether layer liquid with anhydrous magnesium sulfate, filter, and then perform a second rotary evaporation to remove the diethyl ether to obtain 3-benzylamino-2-butenonitrile.

2. The method for preparing 3-benzylamino-2-butenonitrile according to claim 1, characterized in that, The cation exchange membrane is an FKS-50 cation exchange membrane.

3. The method for preparing 3-benzylamino-2-butenonitrile according to claim 1, characterized in that, The cathode is made of copper, nickel, titanium, stainless steel, platinum, or silver.

4. The method for preparing 3-benzylamino-2-butenonitrile according to claim 1, characterized in that, The constant current density in step two is 13.5 mA / cm². 2 .

5. The method for preparing 3-benzylamino-2-butenonitrile according to claim 1, characterized in that, The electrolysis temperature in step two is 15°C.

6. The method for preparing 3-benzylamino-2-butenonitrile according to claim 1, characterized in that, In step two, the charge per mole of benzylamine is 2.2 F.

7. The method for preparing 3-benzylamino-2-butenonitrile according to claim 1, characterized in that, In step one, the molar ratio of quaternary ammonium salt in the cathode electrolyte and the anolyte is 1:2.

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