Deuterium-labeled 3-indole acrylic acid isotope compound and preparation method thereof

Abstract

The invention provides a deuterium-labeled 3-indoleacrylic acid isotope compound and a preparation method thereof, and relates to the technical field of plant hormone detection, deuterated toluene is creatively nitrated and subjected to a ring closing reaction, then an aldehyde group is introduced, and finally hydrolysis is performed to obtain the target product deuterium-labeled 3-indoleacrylic acid isotope compound. The preparation method provided by the invention is strong in operability, relatively good in atom economy and excellent in reproducibility and stability, the isotope abundance of the prepared deuterium-labeled 3-indoleacrylic acid isotope compound can reach 98% or above, the chemical purity is 98% or above, and the deuterium-labeled 3-indoleacrylic acid isotope compound can be used as an internal standard substance for detecting plant hormones and has good application prospects. The method has important practical application value.

Description

Technical Field

[0001] The present invention relates to the technical field of plant hormone detection, in particular to a deuterium-labeled 3-indole acrylic acid isotope compound and a preparation method thereof. Background Art

[0002] 3-Indoleacrylic acid, a metabolite of tryptophan, is a highly effective anti-algae agent. It is also widely used as a plant hormone. 3-Indoleacrylic acid increases the production of reactive oxygen species in East China Sea shrimp and inhibits all nutrient assimilation genes, downregulating the genes for ribulose-1,5-bisphosphate carboxylase / oxygenase II and cytochrome f. Currently, the main methods for detecting 3-Indoleacrylic acid residues in China include high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), radioimmunoassay (RIA), and enzyme-linked immunosorbent assay (ELISA). However, these methods suffer from cumbersome pretreatment procedures and significant matrix effects, which significantly impact the results. Isotope dilution mass spectrometry (IDMS) utilizes stable isotope-labeled compounds as internal standards, effectively combining the separation power of chromatography with the qualitative capabilities of mass spectrometry. Accurate quantification is achieved by comparing the ratio of ions with the standard. This effectively eliminates matrix effects and recovery variations caused by sample pretreatment, improving detection accuracy. Therefore, isotope dilution mass spectrometry (IDMS) is an analytical method with high accuracy and precision.

[0003] The synthesis of naturally abundant and stable isotope-labeled 3-indoleacrylic acid d4 has not been reported in China or abroad. Therefore, the development of a method for preparing isotope-labeled 3-indoleacrylic acid compounds is of great significance for the widespread application of IDMS technology in my country, especially in the detection of 3-indoleacrylic acid. Summary of the Invention

[0004] The purpose of the present invention is to provide a deuterium-labeled 3-indole acrylic acid isotope compound and a preparation method thereof, so as to solve the technical problems of high production cost, low yield and low purity existing in the prior art.

[0005] To solve the above technical problems, the present invention provides a method for preparing a deuterium-labeled 3-indole acrylic acid isotope compound, the specific steps of which are as follows:

[0006] Step 1: Add nitric acid dropwise to acetic anhydride at 0°C and stir for 10-15 minutes. Then, add deuterated toluene dissolved in acetic anhydride dropwise. The mixture reacts at room temperature to obtain 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4.

[0007] Step 2: dissolving the 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4, N,N-dimethylformamide dimethyl acetal, and tetrahydropyrrole in an N,N-dimethylformamide solution, and reacting at a first temperature for 3-5 hours to obtain a first reaction solution; the preferred reaction time is 4 hours;

[0008] After extraction, the organic phase is dried and dissolved in methanol, and palladium carbon is added to obtain a second reaction solution; in a hydrogen environment, the second reaction solution is maintained at a second temperature to react until completion to obtain 1H-indole-3,4,5,6,7-d5;

[0009] Step 3: Add phosphorus oxychloride dropwise to N,N-dimethylformamide at 0° C. and react for 0.5-1 hour to obtain a third reaction solution;

[0010] Dissolving the 1H-indole-3,4,5,6,7-d5 in N,N-dimethylformamide and then adding the mixture dropwise to the third reaction solution; reacting at 35-45° C. for 2-4 hours, adjusting the pH of the third reaction solution to alkaline, and continuously stirring until the reaction is complete to obtain indolecarboxaldehyde-d4;

[0011] Step 4: After mixing triethyl phosphoacetate with the first solvent, sodium hydride is added at 0° C. for reaction for 1-3 hours, preferably 2 hours; then indolecarboxaldehyde-d4 is added, and the reaction is completed at room temperature to obtain (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate;

[0012] Step 5: After mixing the (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate with a second solvent, adding sodium hydroxide, and reacting completely at a third temperature to obtain a deuterium-labeled 3-indole acrylic acid isotope compound.

[0013] Furthermore, in step 4, the first solvent is any one or more mixtures of tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide; preferably tetrahydrofuran;

[0014] In step 5, the second solvent is ethanol and / or water; preferably, the second solvent is a mixed solution of ethanol and water, and the mass ratio of ethanol to water is preferably 4:1.

[0015] Furthermore, the molar ratio of deuterated toluene, nitric acid, and acetic anhydride in step 1 is 1:(3-6):(5-7);

[0016] Preferably, the molar ratio of deuterated toluene, nitric acid and acetic anhydride is 1:5:6;

[0017] The reaction time is 15-20 hours, preferably 16 hours.

[0018] Furthermore, the molar ratio of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4 to N,N-dimethylformamide dimethyl acetal and tetrahydropyrrole in step 2 is 1:(2-4):(2-4);

[0019] Preferably, the molar ratio of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4 to N,N-dimethylformamide dimethyl acetal and tetrahydropyrrole is 1:3:3;

[0020] The first temperature is 100-150°C, preferably 120°C;

[0021] The second temperature is 40-50°C, preferably 45°C.

[0022] Furthermore, the amount of palladium carbon added in step 2 is 8%-15% of the mass of the 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4; preferably 10% of the mass of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4.

[0023] Furthermore, the molar ratio of 1H-indole-3,4,5,6,7-d5 to phosphorus oxychloride in step 3 is 1:(1-1.5);

[0024] Preferably, the molar ratio of 1H-indole-3,4,5,6,7-d5 to phosphorus oxychloride is 1:1.2;

[0025] Furthermore, the pH value of the third reaction solution in step 3 is 8-10;

[0026] Preferably, the pH value of the third reaction solution is adjusted with sodium hydroxide aqueous solution; preferably, the pH value is 8.

[0027] Furthermore, the molar ratio of indolecarboxaldehyde-d4, triethyl phosphoacetate, and sodium hydride in step 4 is 1:(4-6):(4-6);

[0028] Preferably, the molar ratio of indolecarboxaldehyde-d4, triethyl phosphoacetate and sodium hydride is 1:5:5.

[0029] Furthermore, the molar ratio of (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate and sodium hydroxide in step 5 is 1:(2-4);

[0030] Preferably, the molar ratio of (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate and sodium hydroxide is 1:3;

[0031] The third temperature is 60-80°C, preferably 70°C.

[0032] On the other hand, the present invention also provides a deuterium-labeled 3-indole acrylic acid isotope compound, characterized in that the deuterium-labeled 3-indole acrylic acid isotope compound is prepared by the above method, and the structural formula is as follows:

[0033]

[0034] By adopting the above technical solution, the present invention has the following beneficial effects:

[0035] The present invention provides a deuterium-labeled isotope compound of 3-indoleacrylic acid and a preparation method thereof. Deuterated toluene is creatively nitrated, followed by hydrolysis through a series of reactions to obtain the deuterium-labeled isotope compound of 3-indoleacrylic acid. The preparation method provided by the present invention exhibits excellent reproducibility and stability. The prepared deuterium-labeled isotope compound of 3-indoleacrylic acid has an isotopic abundance exceeding 98% and a chemical purity exceeding 98.8%. It can be used as an internal standard for plant hormones and has important practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic diagram of the synthetic route of the preparation method of 3-indoleacrylic acid-d4 provided in Example 1 of the present invention;

[0038] FIG2( a ) is a liquid chromatogram of the deuterium-labeled 3-indoleacrylic acid isotope compound prepared in Example 1;

[0039] FIG2( b ) is a mass spectrum of the deuterium-labeled 3-indoleacrylic acid isotope compound prepared in Example 1;

[0040] Figure 3 This is the H NMR spectrum of the deuterium-labeled 3-indoleacrylic acid isotope compound obtained in Example 1. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] The present invention will be further explained below with reference to specific embodiments.

[0043] The present invention provides a method for preparing a deuterium-labeled 3-indole acrylic acid isotope compound, which comprises the following steps:

[0044] Step 1: Nitric acid is added dropwise to acetic anhydride at 0°C and stirred for 10-15 minutes. Deuterated toluene dissolved in acetic anhydride is then added dropwise. The mixture is reacted at room temperature for 15-20 hours to obtain 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4;

[0045] The molar ratio of deuterated toluene, nitric acid, and acetic anhydride is 1:(3-6):(5-7);

[0046] Step 2: dissolving the 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4, N,N-dimethylformamide dimethyl acetal, and tetrahydropyrrole in an N,N-dimethylformamide solution, and reacting at 100-150° C. for 3-5 hours to obtain a first reaction solution;

[0047] The molar ratio of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4 to N,N-dimethylformamide dimethyl acetal and tetrahydropyrrole is 1:(2-4):(2-4);

[0048] After extraction, the organic phase is dried and dissolved in methanol, and palladium carbon is added with a mass ratio of 8% to 15% of the mass of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4 to obtain a second reaction solution;

[0049] In a hydrogen environment, the second reaction solution is maintained at 40-50° C. to react until completion to obtain 1H-indole-3,4,5,6,7-d5;

[0050] Step 3: Add phosphorus oxychloride dropwise to N,N-dimethylformamide at 0° C. and react for 0.5-1 hour to obtain a third reaction solution;

[0051] The 1H-indole-3,4,5,6,7-d5 is first dissolved in N,N-dimethylformamide, and then the third reaction solution is added dropwise, wherein the molar ratio of 1H-indole-3,4,5,6,7-d5 to phosphorus oxychloride is 1:(1-1.5); after reacting at 35-45° C. for 2-4 hours, the pH value is adjusted to 8-10, and stirring is continued until the reaction is complete to obtain indolecarboxaldehyde-d4;

[0052] Step 4: After mixing triethyl phosphoacetate with the first solvent, sodium hydride is added at 0° C. for reaction for 1-3 hours; then indolecarboxaldehyde-d4 is added, wherein the molar ratio of indolecarboxaldehyde-d4, triethyl phosphoacetate, and sodium hydride is 1:(4-6):(4-6); and the mixture is reacted at room temperature until completion to obtain (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate;

[0053] The first solvent is any one or more mixtures of tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide;

[0054] Step 5: After mixing the (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate with a second solvent, sodium hydroxide is added, wherein the molar ratio of (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate to sodium hydroxide is 1:(2-4); after complete reaction at 60-80° C., 3-indoleacrylic acid d4 is obtained;

[0055] The second solvent is ethanol and / or water.

[0056] Example 1,

[0057] like Figure 1-Figure 3 As shown, according to the method provided by the present invention, a deuterium-labeled 3-indole acrylic acid isotope compound is prepared.

[0058] like Figure 1 As shown, the deuterium-labeled isotope compound of 3-indole acrylic acid is prepared, and the specific steps are as follows:

[0059] Step 1: Slowly drop 9.45 g of nitric acid into 9.2 g of acetic acid at 0°C and stir for 15 minutes. Then, drop 3 g of deuterated toluene dissolved in 9.2 g of acetic acid into the reaction solution and react at room temperature for 16 hours. Pour the reaction solution into water and extract with ethyl acetate. After combining the organic phases, dry the mixture with anhydrous sodium sulfate, filter, and remove the solvent by vacuum distillation. Finally, purify the crude product by Flash column chromatography to obtain 2.9 g of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4.

[0060] Step 2: 2.4 g of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4 obtained in step 1 was dissolved together with 6.1 g of N,N-dimethylformamide dimethyl acetal and 3.6 g of tetrahydropyrrole in 20 mL of N,N-dimethylformamide. The mixture was reacted at 120° C. for 4 hours under nitrogen protection. After the reaction, the reaction solution was poured into water and extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. ESI-MS (m / z): 224 [M+H] + The crude product was dissolved in 15 mL of methanol, and 240 mg of palladium on carbon was added. The reaction was carried out at 45°C for 16 hours in a hydrogen atmosphere. After filtration, the solvent was removed by distillation under reduced pressure. The crude product was purified by Flash column chromatography to obtain 460 mg of 1H-indole-3,4,5,6,7-d5; ESI-MS (m / z): 123 [M+H] + .

[0061] Step 3: 810 mg of phosphorus oxychloride was added dropwise to 4 mL of N,N-dimethylformamide at 0°C for 0.5 hours. 530 mg of 1H-indole-3,4,5,6,7-d5 dissolved in 2 mL of N,N-dimethylformamide was then added dropwise to the reaction solution. The reaction was continued at 40°C for 3 hours. The pH was adjusted to 8 with aqueous sodium hydroxide solution. After stirring and reacting for 16 hours, the reaction solution was poured into water and extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. The crude product was dissolved in water to precipitate a solid, which was filtered and dried to obtain 480 mg of indolecarboxaldehyde-d4; ESI-MS (m / z): 150 [M+H] + .

[0062] Step 4: Dissolve 3.76 g of triethyl phosphoacetate in 20 mL of tetrahydrofuran. Under nitrogen, add 680 mg of 60% pure sodium hydride at 0°C. Heat to 25°C and stir for 2 hours. Then, cool to 0°C and add 500 mg of indolecarboxaldehyde-d4 to the reaction solution. React at room temperature for 16 hours. Quench the reaction with methanol, and remove the solvent from the reaction solution under reduced pressure. The crude product is purified by Flash column chromatography to yield 902 mg of ethyl (E)-3-(1H-indol-3-yl-4,5,6,7-d4)acrylate. ESI-MS (m / z): 220 [M+H]. + .

[0063] Step 5: 902 mg of (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate was dissolved in a solution of 9 mL of ethanol and 2.3 mL of water at room temperature, 515 mg of sodium hydroxide was added, and the mixture was reacted at 70° C. for 3 hours. After the reaction, dichloromethane / water was added for extraction, the organic phase was removed, and the pH of the aqueous phase was adjusted to 5 with 2M HCl solution to precipitate a white solid, which was filtered, washed with water, and lyophilized to obtain 345 mg of 3-indoleacrylic acid d4, i.e., a deuterium-labeled 3-indoleacrylic acid isotope compound, such as Figure 2(a)-Figure 2(b) As shown, ES I-MS (m / z): 192 [M+H] + .

[0064] like Figure 3 Shown: 1H NMR (400 MHz, DMSO-d6) δ 11.88 (s, 1H), 11.72 (s, 1H), 8.00–7.61 (m, 2H), 6.31 (d, J = 16.0 Hz, 1H).

[0065] LSMS detection results show that the isotope abundance of the deuterium-labeled 3-indole acrylic acid isotope compound obtained in Example 1 can reach 98.76%.

[0066] Example 2

[0067] This example verifies the effects of different addition amounts of deuterated toluene on the yield, chemical purity, and isotopic abundance of the deuterium-labeled 3-indoleacrylic acid obtained.

[0068] The preparation conditions of this example are basically the same as those of Example 1, except that the amounts of deuterated toluene used in step 1 are 2 g, 5 g, and 8 g, respectively, to obtain three groups of deuterium-labeled 3-indoleacrylic acid isotope compound samples, which are labeled as Example 2-1, Example 2-2, and Example 2-3, respectively.

[0069] The yield, chemical purity and isotopic abundance of the deuterium-labeled 3-indoleacrylic acid isotope compound obtained in this example are shown in Table 1:

[0070] Table 1 Comparison of the yield, chemical purity and isotopic abundance of the four groups of deuterium-labeled 3-indoleacrylic acid isotope compounds obtained in Example 2 and Example 1

[0071]

[0072]

[0073] As can be seen from Table 1, as the amount of deuterated toluene added increases, the yield of the deuterium-labeled 3-indole acrylic acid isotope compound increases accordingly. When the amount of deuterated toluene added reaches 3g, the yield of the target product deuterium-labeled 3-indole acrylic acid isotope compound reaches 6% and tends to be stable, indicating that the reaction is almost complete and no large amount of target product is generated. The chemical purity and isotopic abundance of the target product do not fluctuate significantly, and the chemical purity is always stable between 98.32% and 98.98%, and the isotopic abundance is even more stable between 98.75% and 98.79%. Therefore, from the perspective of production cost, in the preparation method of the deuterium-labeled 3-indole acrylic acid isotope compound provided by the present invention, the molar ratio of deuterated toluene, nitric acid, and acetic anhydride in step 1 is preferably 1:(3-6):(5-7).

[0074] Example 3

[0075] This example verifies the effect of pH on the yield, chemical purity and isotopic abundance of the obtained deuterium-labeled 3-indoleacrylic acid isotope compound.

[0076] The preparation conditions of this example are basically the same as those of Example 1, except that in step 3, the pH of the reaction environment is adjusted to 7, 9, and 10, respectively, to obtain three groups of deuterium-labeled 3-indoleacrylic acid isotope compounds, which are labeled as Example 3-1, Example 3-2, and Example 3-3, respectively.

[0077] The yield, chemical purity and isotopic abundance of the deuterium-labeled 3-indoleacrylic acid isotope compound obtained in this example are shown in Table 2:

[0078] Table 2 Comparison of yield, chemical purity and isotopic abundance of three groups of deuterium-labeled 3-indole acrylic acid isotope compounds obtained in Example 3

[0079] sample pH Yield (%) Chemical purity (%) Isotope abundance (% atom) Example 3-1 7 5.65 98.36 98.73 Example 3-2 9 5.88 98.91 98.76 Example 3-3 10 5.77 98.64 98.76

[0080] As can be seen from Table 2, the pH value of the reaction environment in step 3 has no significant effect on the chemical purity and isotopic abundance of the deuterium-labeled 3-indole acrylic acid isotope compound. The chemical purity of the three groups of deuterium-labeled 3-indole acrylic acid isotope compounds obtained in this example is all above 98.36%, and the isotopic abundance is also maintained between 98.73% and 98.76%. The yield of the target product is significantly affected by the pH value: when the reaction environment is close to a neutral pH value of 7, the yield of the target product obtained is only 5.65%; when the pH reaches 8, as shown in Table 1, the yield of the target product obtained in Example 1 can reach 6.02%; as shown in Table 2, further increasing the pH value of the reaction environment does not further improve the yield. Therefore, in the preparation method of the deuterium-labeled 3-indole acrylic acid isotope compound provided by the present invention, the pH value of the reaction environment in step 3 is preferably 8-10, and more preferably 8.

[0081] Example 4

[0082] This example verifies the effect of different addition amounts of sodium hydroxide on the yield, chemical purity, and isotopic abundance of deuterium-labeled 3-indoleacrylic acid isotope compounds.

[0083] The preparation conditions of this example are basically the same as those of Example 1, except that in step 5, the molar amount of sodium hydroxide added is 2 times, 3 times, and 4 times that of (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate, to obtain three groups of deuterium-labeled 3-indoleacrylate isotope compounds, which are labeled as Example 4-1, Example 4-2, and Example 4-3, respectively.

[0084] The yields, chemical purities, and isotopic abundances of the three groups of deuterium-labeled 3-indoleacrylic acid isotope compounds obtained in this example are shown in Table 3.

[0085] Table 3 Comparison of the yield, chemical purity and isotopic abundance of the three groups of deuterium-labeled 3-indoleacrylic acid isotope compounds obtained in this example

[0086] sample The addition rate of NaOH Yield (%) Chemical purity (%) Isotope abundance (% atom) Example 4-1 2 5.08 98.15 98.71 Example 4-2 3 6.00 98.74 98.75 Example 4-3 4 5.91 98.87 98.73

[0087] As can be seen from Table 3, the addition of sodium hydroxide does not have a significant effect on the chemical purity and isotopic abundance of the target product. The chemical purity of 3 groups of deuterium-labeled 3-indole acrylic acid isotopic compounds gained in the present embodiment is all more than 98%, and isotopic abundance is more than 98.71%. When the addition molar amount of sodium hydroxide reaches 3 times of (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl propenoate, the productive rate of the gained target product can reach 6%, and when continuing to increase the addition of sodium hydroxide, productive rate no longer significantly increases. Therefore, in the preparation method provided by the invention, the addition molar amount of sodium hydroxide is preferably 3-4 times of (E)-3-(1H-indol-3-yl-4,5,6,7-d4).

[0088] In summary, the yields of the deuterium-labeled 3-indole acrylic acid isotope compounds obtained in Examples 1-4 were calculated, the chemical purity of each group of deuterium-labeled 3-indole acrylic acid isotope compounds was determined by LCMS, and the isotopic abundance of each group of deuterium-labeled 3-indole acrylic acid isotope compounds was determined by ESI-MS, as shown in Table 4:

[0089] Table 4 Detection results of each group of deuterium-labeled 3-indole acrylic acid isotope compounds obtained in Examples 1-4:

[0090] sample Yield (%) Chemical purity (%) Isotope abundance (% atom) Example 1 6.02 98.98 98.76 Example 2-1 5.38 98.32 98.75 Example 2-2 5.95 98.92 98.77 Example 2-3 6.11 98.48 98.79 Example 3-1 5.65 98.36 98.73 Example 3-2 5.88 98.91 98.76 Example 3-3 5.77 98.64 98.76 Example 4-1 5.08 98.15 98.71 Example 4-2 6.00 98.74 98.75 Example 4-3 5.91 98.87 98.73

[0091] The preparation method provided by the present invention creatively nitrates deuterated toluene, and finally hydrolyzes it through a series of reactions to obtain a deuterium-labeled 3-indole acrylic acid isotope compound, which can be used as an internal standard for plant hormones. The preparation method provided by the present invention has a simple process, mild conditions, and excellent reproducibility and stability. The chemical purity and isotope abundance of the obtained target product are less affected by the reaction conditions, which is conducive to the mass production of deuterium-labeled 3-indole acrylic acid isotope compounds. By optimizing the addition amount of deuterated toluene and sodium hydroxide and the pH of the reaction solution, the yield of the deuterium-labeled 3-indole acrylic acid isotope compound prepared by the present invention is significantly improved compared with the existing preparation method, the isotope abundance can reach more than 98%, and the chemical purity reaches more than 98%, which has important practical application value.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a deuterium-labeled 3-indole acrylic acid isotope compound, characterized in that: The specific steps are as follows: Step 1: Add nitric acid dropwise to acetic anhydride at 0°C and stir for 10-15 minutes, then add deuterated toluene dissolved in acetic anhydride dropwise, and react at room temperature to obtain 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4; Step 2: dissolving the 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4, N,N-dimethylformamide dimethyl acetal and tetrahydropyrrole in an N,N-dimethylformamide solution, and reacting at a first temperature for 3-5 hours to obtain a first reaction liquid; after extraction, the organic phase is spin-dried and dissolved in methanol, and palladium carbon is added to obtain a second reaction liquid; in a hydrogen environment, the second reaction liquid is kept at a second temperature to react until complete, to obtain 1H-indole-3,4,5,6,7-d5; Step 3: adding phosphorus oxychloride dropwise to N,N-dimethylformamide at 0°C, reacting for 0.5-1 hour to obtain a third reaction solution; dissolving the 1H-indole-3,4,5,6,7-d5 in N,N-dimethylformamide and then adding dropwise to the third reaction solution; adjusting the pH value of the third reaction solution to alkaline after reacting at 35-45°C for 2-4 hours, and continuing to stir until the reaction is complete to obtain indolecarboxaldehyde-d4; Step 4: After mixing triethyl phosphoacetate with the first solvent, sodium hydride is added at 0° C. to react for 1-3 hours, and then indolecarboxaldehyde-d4 is added and reacted at room temperature until completion to obtain (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate; Step 5: After mixing the (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate with the second solvent, adding sodium hydroxide, and reacting completely at a third temperature to obtain a deuterium-labeled 3-indole acrylic acid isotope compound.

2. The preparation method according to claim 1, characterized in that: In step 4, the first solvent is any one or more mixtures of tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide; In step 5, the second solvent is ethanol and / or water.

3. The preparation method according to claim 1, characterized in that , the molar ratio of deuterated toluene, nitric acid and acetic anhydride in step 1 is 1:(3-6):(5-7); The reaction time is 15-20 hours.

4. The preparation method according to claim 1, characterized in that: The molar ratio of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4, N,N-dimethylformamide dimethyl acetal and tetrahydropyrrole in step 2 is 1:(2-4):(2-4); The first temperature is 100-150°C; the second temperature is 40-50°C.

5. The preparation method according to claim 1, characterized in that: The added mass of palladium carbon in step 2 is 8%-15% of the mass of 1-(methyl-d3)-2-nitrobenzene-3,4,5,6-d4.

6. The preparation method according to claim 1, characterized in that: The molar ratio of 1H-indole-3,4,5,6,7-d5 to phosphorus oxychloride in step 3 is 1:(1-1.5).

7. The preparation method according to claim 1, characterized in that: The pH value of the third reaction solution in step 3 is 8-10.

8. The preparation method according to claim 1, characterized in that: The molar ratio of indolecarboxaldehyde-d4, triethyl phosphoacetate and sodium hydride in step 4 is 1:(4-6):(4-6).

9. The preparation method according to claim 1, characterized in that: The molar ratio of (E)-3-(1H-indol-3-yl-4,5,6,7-d4) ethyl acrylate and sodium hydroxide in step 5 is 1:(2-4); The third temperature is 60-80°C.

10. A deuterium-labeled 3-indoleacrylic acid isotope compound, characterized in that: The compound is prepared by the method described in claims 1-9, and the structural formula is as follows:

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