Methylplumericine derivative intermediates, methods of making and using the same

Abstract

The application belongs to the technical field of drug synthesis, and relates to a methyl delphinene alkaloid derivative intermediate and a preparation method and application thereof. The methyl delphinene alkaloid derivative intermediate is a compound shown in the following structural formula or a tautomer, a mesomer, a racemate, an enantiomer, a diastereomer or a mixture form thereof, or a pharmaceutically acceptable salt thereof: wherein R1 is selected from chlorine, bromine and iodine; and R2 is selected from methyl (Me), acetyl (Ac), benzoyl (Bz), C(O)CF3 and C(O)OEt. The application rapidly synthesizes key tetrahydroisoquinoline intermediates 6 (R-6 or S-6) and 12 (R-12 or S-12) in a simple and efficient route, and synthesizes methyl delphinene and chiral isomers thereof through intermolecular Ullmann reaction of the two, so that the total synthesis efficiency is greatly improved, and the synthesis route is shortened.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical synthesis technology, and relates to intermediates of methylnephrine derivatives, their preparation methods, and applications. Background Technology

[0002] Methyl lotusine is an alkaloid extracted from the embryo of the mature seed of lotus (Nelumbo nucifera), a plant in the Nymphaeaceae family. It is one of the main active components of lotus seed alkaloids and belongs to the dibenzylisoquinoline class of compounds. Modern pharmacological studies have shown that it possesses various effects, including anti-fibrotic, anti-atherosclerotic, anti-hypertensive, anti-thrombotic, anti-platelet aggregation, anti-diabetic vascular complications, vascular protection, anti-arrhythmia, antioxidant, anti-organophosphorus pesticide poisoning, and anti-scarring. It can also act as a novel calcium channel blocker, enhancing the inhibition of human breast cancer cell proliferation by doxorubicin, and is a chemosensitizer. Its structure is as follows:

[0003]

[0004] In recent years, some modern pharmacological studies on methylnephrine have also confirmed that it has sedative-hypnotic activity and has a different mechanism of action than traditional diazepam (Phytomedicine. 2008; 15(12):1117-24; Chem PharmBull (Tokyo). 2013; 61(1):59-68; J Ethnopharmacol. 2021; 267:113511). Previous studies have confirmed that methylnephrine can play an anti-insomnia role as an orexin receptor antagonist (Pharmaceuticals (Basel). 2023, 16(4):542).

[0005] Currently, the preparation of methylcaenin and its derivatives relies on plant extraction. However, the alkaloids contained in lotus seed hearts have similar structures, making separation difficult and hindering large-scale production. To date, there is still no efficient and universal method for isolating these alkaloids from lotus seed hearts, which greatly limits in-depth research on methylcaenin and its derivatives. Summary of the Invention

[0006] The purpose of this invention is to provide a novel intermediate of methyl lotusine derivative, its preparation method, and its application.

[0007] An intermediate of a methylnepenone derivative is a compound with the following structural formula, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof:

[0008]

[0009] Among them, R1 is selected from chlorine, bromine, and iodine;

[0010] R2 is selected from methyl (Me), acetyl (Ac), benzoyl (Bz), C(O)CF3, and C(O)OEt.

[0011] This invention also claims a method for preparing the above-mentioned methylnephrine derivative intermediate, comprising the following steps:

[0012] S1. Compound 1 was obtained by bromination of 4-hydroxyphenylacetic acid under alkaline conditions.

[0013] S2, Compound 1 and 3,4-dimethoxyphenethylamine undergo a condensation reaction to give Compound 2;

[0014] Alternatively, the carboxylic acid on compound 1 is activated to an acyl chloride, which then reacts with 3,4-dimethoxyphenethylamine under alkaline conditions to give compound 2;

[0015] S3 and compound 2 undergo dehydration and ring closure to obtain compound 3;

[0016] S4 and compound 3 were reduced to obtain compound 4;

[0017] S5 and compound 4 react with a methylating agent to methylate the hydrogen atoms on nitrogen to obtain compound 5;

[0018] Compound S6 and compound 5 react with a phenolic hydroxyl protecting agent under alkaline conditions to give compound 6.

[0019] In one preferred embodiment, the bromination reaction step includes: adding 30-40 parts of p-toluenesulfonic acid monohydrate to 20-25 parts of 4-hydroxyphenylacetic acid, followed by slowly adding 30-40 parts of the brominating agent at -15 to -25°C, and reacting overnight.

[0020] In one preferred embodiment, the brominating agent includes either bromine water or N-bromosuccinimide, preferably N-bromosuccinimide.

[0021] In one preferred embodiment, the condensation reaction step includes: adding 50-55 parts of condensing agent and 55-60 parts of 3,4-dimethoxyphenylethylamine to 45-50 parts of compound 1, and reacting at room temperature for 2-3 hours.

[0022] In one preferred embodiment, the condensing agent is selected from 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), N,N'-carbonyldiimidazole (CDI), dicyclohexylcarbodiimide (DCC), 1-hydroxy-7-azabenzotriazole (HOAT), 1-hydroxybenzotriazole (HOBt), 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate (HATU), preferably CDI.

[0023] In one preferred embodiment, the molar ratio of compound 1 to CDI is 1.0 to 1.5:1; the molar ratio of compound 1 to 3,4-dimethoxyphenethylamine is 1 to 1.5:1; the reaction temperature is 0-30°C; and the reaction time is 2-5 hours.

[0024] Both condensing agents CDI and EDCI can promote the formation of amide bonds, with CDI being slightly more effective. The dosage should be between 1.0 and 1.5 moles.

[0025] In one preferred embodiment, compound 1 is mixed with oxalyl chloride or thionyl chloride and refluxed for 3-4 hours to obtain acyl chloride.

[0026] In one preferred embodiment, the dehydration and ring-closing step includes: adding a dehydration condensing agent to compound 2 and reacting for 1-4 hours under nitrogen atmosphere.

[0027] In one preferred embodiment, the dehydrating condensing agent is one of phosphorus oxychloride, phosphorus trichloride, phosphorus pentoxide, trifluoromethanesulfonic anhydride and 2-fluoropyridine, preferably trifluoromethanesulfonic anhydride and 2-fluoropyridine.

[0028] In one preferred embodiment, the molar ratio of compound 2 to the dehydrating agent is 1:1 to 3.0, the reaction temperature is 0°C to reflux, and the reaction time is 10 minutes to 2 hours.

[0029] In one preferred embodiment, the step of reducing compound 3 in step S4 includes: adding 70-80 parts of reducing agent to 150-250 parts of compound 3, reacting at room temperature for 1-2 hours, and adding water to terminate the reaction after the reaction is complete.

[0030] In one preferred embodiment, the reducing agent is selected from sodium borohydride, sodium cyanoborohydride, sodium triacetylborohydride, lithium aluminum hydride, or potassium borohydride, with sodium borohydride being preferred.

[0031] In one preferred embodiment, the molar ratio of compound 3 to reducing agent is 1:1 to 5, the reaction temperature is reflux at or below 0°C, and the reaction time is 1 to 3 hours.

[0032] In one preferred embodiment, the catalyst required for the synthesis of compound 4 is selected from (S,S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine (p-isopropylbenzene) ruthenium chloride or (R,R)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine (p-isopropylbenzene) ruthenium chloride, (S,S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine phenyl ruthenium chloride or (R,R)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine phenyl ruthenium chloride. (S,S)-TSDPEN-RU (mesotriene) CL or (R,R)-TSDPEN-RU (mesotriene) CL, preferably (S,S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine (p-isopropylbenzene) ruthenium chloride or (R,R)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine (p-isopropylbenzene) ruthenium chloride.

[0033] In one preferred embodiment, the molar ratio of compound 3 to the catalyst is 1:1-2%.

[0034] In one preferred embodiment, the methylation step includes adding 1-4 parts of formaldehyde and 450-550 parts of sodium borohydride to 450-550 parts of compound 4, reacting for 3-4 hours, and then adding water to terminate the reaction.

[0035] In one preferred embodiment, the phenolic hydroxyl protecting agent is bromomethyl methyl ether (MOMBr).

[0036] In one preferred embodiment, the reaction step S6 includes: adding 2-3 parts of sodium hydride or 12-15 parts of N,N-diisopropylethylamine (DIPEA) and 6-8 parts of MOMBr to 15-25 parts of compound 5, reacting for 5-40 minutes, and then adding water to terminate the reaction.

[0037] In the above reactions, sodium hydride is more effective than N,N-diisopropylethylamine.

[0038] In one preferred embodiment, the molar ratio of compound 5 to the phenolic hydroxyl protecting agent MOMBr is 1:1 to 5.

[0039] In one preferred embodiment, the reaction system of S6 further includes a base.

[0040] In one preferred embodiment, the base is selected from potassium hydroxide (KOH), sodium hydroxide (NaOH), carbonate (K2CO3), sodium hydride (NaH), pyridine, triethylamine (TEA), or N,N-diisopropylethylamine (DIPEA).

[0041] In one preferred embodiment, the reaction system of S6 further includes a solvent, which is one of dichloromethane, tetrahydrofuran, N,N-dimethylformamide and acetonitrile, preferably tetrahydrofuran.

[0042] In the above reaction, the solvent tetrahydrofuran is more effective than N,N-dimethylformamide.

[0043] In one preferred embodiment, the amounts of bromomethyl methyl ether (MOMBr) and sodium hydride are 1.0-1.2 times that of compound 5.

[0044] In one preferred embodiment, the reaction time is 5-10 minutes; if the reaction time is too long or too short, the yield will decrease significantly.

[0045] The dosage of MOMBr and sodium hydride, as well as the reaction time, are key influencing factors. If the dosage of MOMBr and sodium hydride is too long or too short, the yield will decrease significantly.

[0046] This invention also claims the use of the above-mentioned methylnephrine derivative intermediate in the preparation of compound 13, the structure of which is as follows:

[0047]

[0048] In one preferred embodiment, the intermediate of the methyl lotusine derivative shown in Formula 6 and compound 12 are reacted with a catalyst and a ligand under alkaline high-temperature conditions to obtain the compound 12 via a Ullmann reaction. The structure of compound 12 is as follows:

[0049]

[0050] R is selected from methyl (Me), acetyl (Ac), benzoyl (Bz), C(O)CF3, and C(O)OEt.

[0051] In one preferred embodiment, the catalyst is selected from cuprous oxide, cuprous iodide, cuprous bromide, copper, copper oxide, or a mixture of cuprous dimethyl sulfide, preferably a mixture of cuprous dimethyl sulfide.

[0052] In the above reactions, the mixture of cuprous bromide and dimethyl sulfide is more effective and has a higher yield than cuprous oxide, cuprous iodide, cuprous bromide, copper, and copper oxide.

[0053] In one preferred embodiment, the ligand is selected from one of 1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, N,N-dimethylglycine, N1,N2-bis([1,1'-biphenyl]-2-yl)glyoxamide, 2-pyridinecarboxylic acid, and 2-pyridinecarboxylic acid·pyridine salt, wherein 2-pyridinecarboxylic acid is more effective.

[0054] In one preferred embodiment, the alkali is selected from potassium phosphate, potassium carbonate, cesium carbonate, and cesium fluoride, with potassium phosphate being more effective.

[0055] In one preferred embodiment, the solvent is selected from toluene, dimethyl sulfoxide, 1,4-dioxane, acetonitrile, N,N-dimethylformamide, and pyridine, with pyridine being more effective.

[0056] In one preferred embodiment, the molar ratio of compound 6 to compound 12 is 1:0.5 to 2, the molar ratio of compound 6 to catalyst is 1:0.1 to 2.0, the molar ratio of compound 6 to ligand is 1:0.1 to 2.0, the molar ratio of compound 6 to base is 1:1 to 5.0, the reaction temperature is 80℃-150℃, and the reaction time is 2-7 days.

[0057] An excessively high or low ratio of raw materials, an excessively long or short cooking time, or an excessively high or low temperature will all significantly affect the yield. The optimal yield is achieved within this range.

[0058] In one preferred embodiment, the method for preparing compound 12 includes:

[0059] (1) Using vanillin as a raw material, compound 7 was synthesized by reacting it with nitromethane via Henry reaction under the action of a catalyst;

[0060] (2) Compound 7 was reduced to synthesize compound 8 under the action of a reducing agent;

[0061] (3) Compound 8 is synthesized by condensation reaction with 4-methoxyphenylacetic acid under the action of a condensing agent; or Compound 8 is activated to acyl chloride and reacted with 4-methoxyphenylacetic acid under alkaline conditions to synthesize compound 9.

[0062] (4) Compound 9 was cyclically closed in an inert solvent by the action of a dehydrating agent to synthesize compound 10;

[0063] (5) Compound 10 was reduced to compound 11 under the action of a reducing agent;

[0064] (6) Compound 11 was reacted with a methylating agent to synthesize compound 12.

[0065] In one preferred embodiment, in step (1), the catalyst is selected from one of triethylamine, ethylenediamine, ammonium acetate, and ammonium acetate, preferably ammonium acetate.

[0066] In one preferred embodiment, in step (1), the molar ratio of vanillin to nitromethane is 1:1 to 5, the reaction temperature is 25°C-reflux, and the reaction time is 3-12 hours;

[0067] In one preferred embodiment, in step (2), the reducing agent is selected from one of nickel powder, zinc powder, and lithium aluminum hydride, preferably lithium aluminum hydride; the solvent is selected from one of tetrahydrofuran, methanol, or toluene, preferably tetrahydrofuran;

[0068] In one preferred embodiment, in step (2), the molar ratio of compound 7 to reducing agent is 1:1 to 10, the reaction temperature is 0°C to reflux, and the reaction time is 8 to 24 hours.

[0069] In one preferred embodiment, in step (3), the condensing agent is selected from EDCI, CDI, DCC, HOAt, HOBt, HATU, preferably EDCI and HOAt; the reagent for activating the carboxylic acid to acyl chloride is selected from one of oxaloyl chloride and sulfonium chloride, preferably sulfonium chloride; and the solvent is selected from one of dichloromethane, water, tetrahydrofuran, ethyl acetate or N,N-dimethylformamide, preferably dichloromethane and water.

[0070] In one preferred embodiment, in step (3), the molar ratio of 4-methoxyphenylacetic acid to sulfoxide is 1.2 to 3:1; the molar ratio of compound 8 to 4-methoxyphenylacetic acid is 1:1.0 to 1.3; the reaction temperature is 0-50°C; and the reaction time is 3-12 hours.

[0071] In one preferred embodiment, in step (4), the solvent is selected from one of dichloromethane, N,N-dimethylformamide, acetonitrile or toluene, preferably dichloromethane; the dehydrating agent is selected from one of phosphorus oxychloride, phosphorus trichloride, phosphorus pentoxide, trifluoromethanesulfonic anhydride and 2-fluoropyridine, preferably trifluoromethanesulfonic anhydride and 2-fluoropyridine.

[0072] In one preferred embodiment, in step (4), the molar ratio of compound 9 to dehydrating agent is 1:1 to 3.0, the reaction temperature is reflux below 0°C, and the reaction time is 10 minutes to 12 hours.

[0073] In one preferred embodiment, in step (5), the reducing agent required for the synthesis of compound 11 is selected from sodium borohydride, sodium cyanoborohydride, sodium triacetylborohydride, lithium aluminum hydride or potassium borohydride, preferably sodium borohydride; the solvent is selected from methanol, ethanol, dichloromethane or tetrahydrofuran, preferably methanol.

[0074] In one preferred embodiment, in step (5), the molar ratio of compound 10 to reducing agent is 1:1 to 5, the reaction temperature is 0°C to reflux, and the reaction time is 1 to 3 hours.

[0075] In one preferred embodiment, in step (5), the catalyst required for the synthesis of the R-configuration or S-configuration compound 11 is selected from (S,S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine (p-isopropylbenzene) ruthenium chloride or (R,R)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine (p-isopropylbenzene) ruthenium chloride, (S,S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine phenyl ruthenium chloride or ( R,R)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine phenyl ruthenium chloride, (S,S)-TSDPEN-RU (trimethylbenzene) CL or (R,R)-TSDPEN-RU (trimethylbenzene) CL, preferably (S,S)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine (p-isopropylbenzene) ruthenium chloride or (R,R)-N-(p-toluenesulfonyl)-1,2-diphenylethanediamine (p-isopropylbenzene) ruthenium chloride.

[0076] In one preferred embodiment, in step (6), the solvent is selected from methanol, N,N-dimethylformamide, tetrahydrofuran, acetonitrile, and dichloromethane, and the methylating agent is selected from formic acid, formaldehyde, potassium iodide, methyl p-toluenesulfonate, dimethyl carbonate, or dimethyl sulfate, preferably formaldehyde.

[0077] In one preferred embodiment, in step (6), the molar ratio of compound 11 to the methylating agent is 1:1 to 10, the reaction temperature is 20°C-reflux, and the reaction time is 1-10 hours.

[0078] A methylnepenone derivative is a compound with the following structural formula, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof:

[0079]

[0080] This invention also claims the use of the above-mentioned methylcaenine derivative in the preparation of methylcaenine, the structure of which is as follows:

[0081]

[0082] In one preferred embodiment, compound 13 is deprotected by a phenolic hydroxyl protecting group under acidic or alkaline conditions to yield methyl lotusine.

[0083] In one preferred embodiment, the molar ratio of compound 13 to the acidic reagent is 1:10 to 100, the reaction temperature is reflux below 20°C, and the reaction time is 6 to 12 hours.

[0084] The present invention also provides the use of the methylcaesin derivative intermediate of the present invention or a pharmaceutical composition containing the methylcaesin derivative intermediate in the preparation of a medicament by antagonizing orexin receptors.

[0085] In one preferred embodiment, the pharmaceutical composition comprises at least one compound of the present invention and optionally a pharmaceutically acceptable excipient.

[0086] The advantages of this invention are as follows: Based on the limitations of the cumbersome and difficult-to-obtain large quantities natural extraction and separation of methylcaenine, this invention utilizes readily available and inexpensive commercial chemical products as starting materials to rapidly synthesize the key tetrahydroisoquinoline intermediates 6 (R-6 or S-6) and 12 (R-12 or S-12) via a simple and efficient route. Methylcaenine and its chiral isomers are then synthesized through the intermolecular Ullmann reaction between these two intermediates. This synthetic route employs a convergent synthesis strategy and develops a new Ullmann reaction optimization method, greatly improving the total synthesis efficiency and shortening the synthetic route. Based on this synthetic route, using vanillin as the starting material, the longest linear step requires only 9 steps to complete the gram-scale synthesis of methylcaenine, with a linear yield as high as 34.9%. This is also the first reported total synthesis route for methylcaenine, possessing industrial scale-up value. The application of methylcaenine and its chiral isomers as orexin receptor antagonists in the treatment of insomnia also provides valuable reference for the development of new insomnia drugs. Attached Figure Description

[0087] Figure 1 The 1H NMR spectrum of (±)-Nef;

[0088] Figure 2 The NMR carbon spectrum of (±)-Nef;

[0089] Figure 3 The hydrogen NMR spectrum of Nef;

[0090] Figure 4 The image shows the carbon NMR spectrum of Nef.

[0091] Figure 5 The hydrogen NMR spectrum of (R,S)-Nef;

[0092] Figure 6 The carbon NMR spectrum of (R,S)-Nef;

[0093] Figure 7 The hydrogen NMR spectrum of (S,R)-Nef is shown.

[0094] Figure 8 The carbon NMR spectrum of (S,R)-Nef;

[0095] Figure 9The 1H NMR spectrum of (S,S)-Nef is shown.

[0096] Figure 10 The carbon NMR spectrum of (S,S)-Nef;

[0097] Figure 11 Results of flow cytometry analysis of changes in intracellular calcium ion concentration in CHO cells. Detailed Implementation

[0098] The present invention will be further described below with reference to embodiments. The embodiments below can help those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

[0099] Example 1: Total Synthesis of the Racemic Compound of Methylnephrine

[0100] Preparation of Compound 1

[0101]

[0102] Method A: In a 500 mL reaction flask, 25.0 g of 4-hydroxyphenylacetic acid was added to 200 mL of acetonitrile, followed by 34.4 g of p-toluenesulfonic acid monohydrate. Then, 32.1 g of N-bromosuccinimide was slowly added at -20 °C. The reaction was carried out overnight at -20 °C, followed by filtration. The filtrate was concentrated under reduced pressure, and then washed with 500 mL of ethyl acetate, saturated sodium bisulfite solution, and water. The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to give a white solid, 34.5 g, of compound 1 (yield 91%).

[0103] Method B: In a 500 mL reaction flask, 5.0 g of 4-hydroxyphenylacetic acid was added to 50 mL of acetic acid. 5.3 g of bromine was slowly added at -10 °C. The reaction was carried out overnight at 0 °C. The acetic acid was removed by concentration under reduced pressure. The mixture was then washed with 500 mL of ethyl acetate, saturated sodium bisulfite solution, and water. The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain a white solid, 5.8 g, of compound 1 (77% yield).

[0104] The spectral data of compound 1 are as follows: 1 H NMR (500MHz, CDCl3) δ7.38(d,J=2.1Hz,1H),7.11(dd,J=8.3,2.1Hz,1H),6.96(d,J=8.3Hz,1H),3.54(s,2H).

[0105] For the preparation of compound 2:

[0106]

[0107] Method A: In a 25 mL reaction flask, 500 mg of compound 1 was added to 3 mL of dichloromethane, followed by 351 mg of CDI and 398 mg of 3,4-dimethoxyphenylethylamine. The reaction was carried out at room temperature for 2 hours. After the reaction was complete, 50 mL of dichloromethane was added, and the mixture was washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and recrystallized from petroleum ether and dichloromethane to give a white solid, 597 mg, with a yield of 97%.

[0108] Method B: In a 25 mL reaction flask, 500 mg of compound 1 was added to 3 mL of dichloromethane, followed by 414.9 mg of EDCI and 398 mg of 3,4-dimethoxyphenylethylamine. The reaction was carried out at room temperature for 2 hours. After the reaction was complete, 50 mL of dichloromethane was added, and the mixture was washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and recrystallized from petroleum ether and dichloromethane to give a white solid, 547 mg, with a yield of 66%.

[0109] Method C: In a 100 mL reaction flask, 3 g of compound 1, 2.39 g of 3,4-dimethoxyphenylethylamine, 3.23 g of EDCI, and 2.3 g of HOAt were added to 26 mL of dichloromethane and reacted at room temperature for 5 hours. After the reaction was complete, 300 mL of dichloromethane was added, and the mixture was washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and recrystallized to give 4.28 g of a white solid, with a yield of 84%.

[0110] Method D: In a 50 mL reaction flask, 2 g of compound 1 was added to 17 mL of dichloromethane, followed by 515 mg of thionyl chloride and 0.1 mL of DMF. After reflux for 3 hours, the mixture was concentrated under reduced pressure to obtain the acyl chloride. 1.2 g of 3,4-dimethoxyphenylethylamine and 1 g of potassium carbonate were dissolved in 12 mL of dichloromethane and 6 mL of water. The dichloromethane solution of the acyl chloride was then added dropwise, and the mixture was reacted at room temperature for 2 hours. After the reaction was complete, 100 mL of dichloromethane was added, and the mixture was washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and recrystallized to give 2.55 g of a white solid, with a yield of 90%.

[0111] Reaction analysis: Both condensing agents CDI and EDCI can promote amide bond formation, but CDI is slightly more effective in this invention, with a dosage between 1.0 and 1.5 moles. Even under optimal reaction conditions, i.e., reaction C, the yield of EDCI is only 84%, lower than that of CDI. Furthermore, SOCl2 activation of carboxylic acids yields acyl chlorides, which can also react efficiently with amines.

[0112] Compound 2 data are as follows: ESI-HRMS m / z calcd C 18 H 21 BrNO4[M+H] + 394.0648, found 394.0619.1 H NMR(400MHz,DMSO)δ10.06(s,1H),7.99(t,J=5.2Hz,1H,-NH),7.34(s,1H,Ar-H),7.0 0(d,J=8.4Hz,1H,Ar-H),6.85(dd,J=8.4,2.0Hz,1H,Ar-H),6.82(d,J=8.4Hz,1H,Ar-H ),6.77(d,J=2.0Hz,1H,Ar-H),6.64(dd,J=8.0,1.6Hz,1H,Ar-H),3.71(s,6H,-OCH3,- OCH3,),3.26(s,2H,-C(O)CH2),3.25-3.20(m,2H,-CH2),2.62(t,J=7.2Hz,2H,-CH2). 13 C NMR (125MHz, CDCl3) δ170.8,151.9,149.4,148.0,141.7,133.0,131.2,130 .4,128.6,120.9,116.7,112.0,111.6,110.7,56.2,56.1,42.7,40.9,35.2.

[0113] Preparation of compound 3:

[0114]

[0115] Method A: In a 50 mL reaction flask, 500 mg of compound 2 was added to 6.6 mL of dichloromethane. Then, under nitrogen protection, 251 mg of difluoropyridine and 445 mg of trifluoromethanesulfonic anhydride were added at 0 °C, and the reaction was carried out at room temperature for 1 hour. After the reaction was complete, 10 mL of dichloromethane was added, at which point a white solid precipitated. Filtering yielded 445.4 mg of the white solid, which was identified as compound 3, with a yield of 89%.

[0116] Method B: In a 10 mL reaction flask, 50 mg of compound 2 was added to 1.4 mL of acetonitrile, followed by the addition of 60.5 mg of phosphorus oxychloride under nitrogen protection. The mixture was heated to reflux for 3 hours. After the reaction was complete, the mixture was cooled and 1 mL of water was added to terminate the reaction. The reaction was extracted with 20 mL of dichloromethane and washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and separated by column chromatography to obtain 42 mg of compound 3 as a white solid, with a yield of 85%.

[0117] Reaction analysis: POCl3, difluoropyridine, and trifluoromethanesulfonic anhydride are all good dehydrating condensing agents. The preferred reaction temperature for difluoropyridine and trifluoromethanesulfonic anhydride is 0℃ to room temperature, and more preferably room temperature. The preferred reaction temperature for POCl3 is 30℃ to 90℃, and more preferably the solvent reflux temperature. Under the above conditions, compounds 1 to 3 can all be obtained as pure products by recrystallization without the need for column chromatography.

[0118] Compound 3 data are as follows: ESI-HRMS m / z calcd C 18 H 19 BrNO3[M+H] + 376.0543, found 376.0565. 1 H NMR (600MHz, CDCl3) δ7.31(d,J=1.4Hz,1H,Ar-H),6.99(d,J=7.1Hz,1H,Ar-H),6.72(d,J=8.1Hz,1H,Ar-H),6.60(s,1H,Ar-H)),6. 57(s,1H,Ar-H),5.27(s,1H,-OH),4.14(dd,J=9.6,3.9Hz,1H,NCH-),3.84(s,3H,-OCH3),3.81(s,3H,-OCH3),3.26-3.20(m,1H,-C H 2),3.12(dd,J=14.0,4.1Hz,1H,-C H 2), 3.03-2.92(m,2H,-C H 2), 2.80-2.67(m,3H,-C) H 2). 13 C NMR (125MHz, DMSO) δ175.2,155.9,153.8,147.9,134.6,133.8,129.7,125.5,116.9,116.7,113.0,111.7,109.8,56.4,56.3,41.0,36.9,24.5.

[0119] Preparation of the racemic mixture of compound 4:

[0120]

[0121] In a 50 mL reaction flask, 195 mg of compound 3 was added to 6.5 mL of methanol, followed by the addition of 73.8 mg of sodium borohydride at 0 °C. The reaction was allowed to proceed for 1 hour at room temperature. After the reaction was complete, 1 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the mixture was extracted with 50 mL of dichloromethane. The mixture was washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain 189 mg of the racemic form of compound 4 as a pale yellow liquid, with a yield of 95%.

[0122] The data for compound 4 are as follows: ESI-HRMS m / z calcd C 18 H 21 BrNO3[M+H] + 378.0699, found 378.0704. 1 H NMR (600MHz, DMSO) δ7.42(d,J=1.8Hz,1H,Ar-H),7.08(dd,J=8.4,1.8Hz,1H,Ar-H),6.86(d,J=8.4Hz,1H,Ar-H)),6.75(s,1H ,Ar-H)),6.61(s,1H,Ar-H)),3.93(dd,J=9.0,3.0Hz,1H,NCH-),3.70(s,3H,-OCH3),3.68(s,3H,-OCH3),3.09-3.03(m,1H,-C H 2),3.01(dd,J=13.8,4.2Hz,1H,-C H 2), 2.79-2.74(m, 1H, -C) H 2),2.67(dd,J=13.8,9.6Hz,1H,-C H 2), 2.63-2.53(m,2H,-C H 2). 13 C NMR (150MHz, CDCl3) δ152.1,147.9,147.4,133.1,131.6,129.9,129.7,127.1 ,116.9,112.0,110.8,109.5,56.9,56.2,56.1,53.6,46.5,41.7,40.6,29.2.

[0123] Preparation of the racemic mixture of compound 5

[0124]

[0125] Method A (stepwise method): In a 50 mL reaction flask, 500 mg of the racemic mixture of compound 4 was added to 6 mL of methanol, followed by 2.6 mL of formaldehyde. 498 mg of sodium borohydride was slowly added at 0 °C, and the reaction was allowed to proceed for 3 hours at room temperature. After the reaction was complete, 5 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the reaction mixture was extracted with 100 mL of dichloromethane. The mixture was washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain 514 mg of the racemic mixture of compound 5 as a white solid, with a yield of 93%.

[0126] Method B (One-pot method): In a 100 mL reaction flask, 2.0 g of compound 3 was added to 20 mL of methanol, followed by the addition of 1.0 g of sodium borohydride at 0 °C. The reaction was carried out at room temperature for 1 hour. After the reaction was complete, 1.1 mL of formaldehyde was added, and the reaction was carried out at room temperature for 3 hours. After the reaction was complete, 5 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the reaction was extracted with 200 mL of dichloromethane. The mixture was washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to give 1.85 g of the racemic mixture of compound 5 as a white solid, with a yield of 89%.

[0127] Reaction analysis: Compound 3, after reduction with sodium borohydride, can be directly subjected to the next N-methylation reaction without further treatment to obtain compound 5. The data for compound 5 are as follows: ESI-HRMS m / z calcd C 19 H 23 BrNO3[M+H] + 392.0856, found 392.0882. 1 H NMR (600MHz, CDCl3) δ7.18(d,J=1.8Hz,1H,Ar-H),6.92(dd,J=8.4,1.8Hz,1H,Ar-H),6.87(d,J=8.4Hz,1H,Ar-H),6.54(s ,1H,Ar-H),6.07(s,1H,Ar-H),3.82(s,3H,-OCH3),3.66(t,J=6.0Hz,1H,NCH-),3.61(s,3H,-OCH3),3.22-3.14(m,1H,-C H 2), 3.14-3.05(m, 1H, -C H 2), 2.85-2.71(m,3H,-C H 2), 2.59-2.57(m, 1H, -C) H 2), 2.51(s,3H,-NCH3). 13C NMR (150MHz, DMSO) δ146.9,146.5,133.3,129.7,129.5,126.1,116.6,111.7,111.4,64.3,55.4,55.3,46.5,42.5,24.8.

[0128] Preparation of the racemic mixture of compound 6

[0129]

[0130] Method A: In a 5 mL reaction flask, 20 mg of the racemic mixture of compound 5 was added to 0.5 mL of tetrahydrofuran, followed by 2.0 mg of sodium hydride. 6.4 mg of MOMBr was slowly added at 0 °C, and the reaction was allowed to proceed for 5 minutes at room temperature. After the reaction was complete, 1 mL of water was added to terminate the reaction. The tetrahydrofuran was removed by concentration under reduced pressure, and the reaction was extracted with 20 mL of dichloromethane. The mixture was washed twice with water and saturated brine. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and separated by column chromatography to obtain 15.3 mg of the racemic mixture of compound 6, a pale yellow liquid, with a yield of 69%.

[0131] Method B: In a 5 mL reaction flask, 20 mg of the racemic 5-component of compound was added to 0.5 mL of tetrahydrofuran, followed by 6.6 mg of DIPEA (in the same molar ratio as sodium hydride). 6.4 mg of MOMBr was slowly added at 0 °C, and the reaction was allowed to proceed overnight at room temperature. The reaction was extracted with 20 mL of dichloromethane, washed twice with water and saturated brine, and the organic phase was dried over anhydrous sodium sulfate. After filtration, concentration under reduced pressure, and column chromatography, 8.9 mg of the racemic 6-component of compound was obtained as a pale yellow liquid, with a yield of 40%.

[0132] Method C: In a 5 mL reaction flask, 20 mg of the racemic mixture of compound 5 was added to 0.5 mL of tetrahydrofuran, followed by 2.5 mg of sodium hydride. 7.6 mg of MOMBr was slowly added at 0 °C, and the reaction was allowed to proceed for 5 minutes at room temperature. After the reaction was complete, 0.2 mL of water was added to terminate the reaction. The tetrahydrofuran was removed by concentration under reduced pressure, and the reaction was extracted with 20 mL of dichloromethane. The mixture was washed twice with water and saturated brine. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and separated by column chromatography to obtain 12.2 mg of the racemic mixture of compound 6, a pale yellow liquid, with a yield of 55%.

[0133] Method D: In a 5 mL reaction flask, 20 mg of the racemic mixture of compound 5 was added to 0.5 mL of tetrahydrofuran, followed by 2.5 mg of sodium hydride. 7.6 mg of MOMBr was slowly added at 0 °C, and the reaction was allowed to proceed for 30 minutes at room temperature. After the reaction was complete, 0.2 mL of water was added to terminate the reaction. The tetrahydrofuran was removed by concentration under reduced pressure, and the reaction mixture was extracted with 20 mL of dichloromethane. The mixture was washed twice with water and saturated brine. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then separated by column chromatography to obtain 7.1 mg of the racemic mixture of compound 6, a pale yellow liquid, with a yield of 32%.

[0134] Method E: In a 5 mL reaction flask, 20 mg of the racemic 5-component of compound was added to 0.5 mL of N,N-dimethylformamide, followed by 2.5 mg of sodium hydride. 7.6 mg of MOMBr was slowly added at 0 °C, and the reaction was allowed to proceed for 5 minutes at room temperature. After the reaction was complete, 0.2 mL of water was added to terminate the reaction. The reaction was extracted with 20 mL of dichloromethane, washed twice with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and separated by column chromatography to obtain 6.0 mg of the racemic 6-component of compound, a pale yellow liquid, with a yield of 27%.

[0135] Method F: In a 5 mL reaction flask, 20 mg of the racemic 5-component of compound was added to 0.5 mL of N,N-dimethylformamide, followed by the addition of 10.2 mg of sodium hydride. 20.8 mg of MOMBr was then slowly added at 0 °C, and the reaction was carried out at room temperature for 5 minutes. No target product was formed.

[0136] Reaction Analysis: In the above reactions, sodium hydride was more effective than DIPEA, and tetrahydrofuran was more effective than N,N-dimethylformamide. The amounts of MOMBr and sodium hydride, as well as the reaction time, were the key influencing factors. The optimal molar amounts of MOMBr and sodium hydride were 1.0 times that of compound 4, with an optimal molar ratio range of 1:1.0–1.2. The reaction time was 5–10 minutes; prolonged reaction time significantly reduced the yield.

[0137] Compound 6 data are as follows: ESI-HRMS m / z calcd C 21 H 27 BrNO4[M+H] + 436.1118, found 436.1126. 1H NMR(500MHz,DMSO)δ7.40(d,J=1.5Hz,1H,Ar-H),7.10(dd,J=8.5,1.5Hz,1H,Ar-H),7.06(d,J=8.5Hz,1H,Ar-H),6.61(s,1H,Ar-H),6.47(s, 1H,Ar-H),5.22(s,2H,-OCH2O-),3.69(s,3H,-OCH3),3.66-3.62(m,1H,NCH-),3.59(s,3H,-OCH3),3.39(s,3H,-OCH3),3.16-3.07(m,1H,-C H 2),2.95(dd,J=14.0,7.0Hz,1H,-C H 2),2.83(dd,J=14.0,5.5Hz,1H,-C H 2), 2.76-2.66(m, 1H, -C) H 2), 2.66-2.59(m, 1H, -C) H 2), 2.47-2.41(m,1H,-C H 2), 2.35(s,3H,-NCH3). 13 C NMR (150MHz, DMSO) δ151.2,147.1,146.7,146.6,135.3,134.0,134.0,130.1,128.7,12 6.0,115.8,111.7,111.4,111.3,94.7,63.9,56.0,55.4,55.4,46.2,42.2,39.0,24.3.

[0138] Preparation of compound 7

[0139]

[0140] Method A: In a 100 mL reaction flask, 2 g of vanillin was added to 4 mL of nitromethane, followed by 20.4 mg of ammonium acetate. The mixture was refluxed at 110 °C overnight. After the reaction was complete, it was cooled to room temperature. The nitromethane was removed by concentration under reduced pressure, and methanol and water (9 mL, 2:1) were added to precipitate a large amount of solid. After filtration, the solid was washed with water and a small amount of ethanol to give 2.26 g of a yellow solid, with a yield of 88%.

[0141] Method B: In a 100 mL reaction flask, 2 g of vanillin was added to 4 mL of nitromethane, followed by 266 mg of triethylamine (in the same molar amount as ammonium acetate). The mixture was refluxed at 110 °C overnight. After the reaction was complete, the mixture was cooled to room temperature, concentrated under reduced pressure to remove the nitromethane, and then methanol and water (9 mL, 2:1) were added to precipitate a large amount of solid. After filtration, the solid was washed with water and a small amount of ethanol to give 810 mg of a yellow solid, with a yield of 32%.

[0142] Method C: In a 100 mL reaction flask, 2 g of vanillin was added to 4 mL of nitromethane, followed by 349 mg of ethylenediamine hydrochloride (in the same molar amount as ammonium acetate) and 105 mg of sodium hydroxide. The mixture was refluxed at 110 °C overnight. After the reaction was complete, the mixture was cooled to room temperature, concentrated under reduced pressure to remove the nitromethane, and methanol and water (9 mL, 2:1) were added to precipitate the solid. The precipitate was filtered and washed with water and a small amount of ethanol to give 74 mg of a yellow solid, with a yield of 29%.

[0143] Reaction analysis: Ammonium acetate was the best catalyst among ammonium acetate, triethylamine and ethylenediamine hydrochloride.

[0144] The data for compound 7 are as follows: 1 H NMR (600MHz, CDCl3) δ7.49 (dd, J=13.5, 3.2Hz, 1H), 7.26 (dd, J=13.5, 3.1Hz, 1H), 6.71 (d, J= 2.0Hz, 1H), 6.66 (dd, J=8.2, 2.0Hz, 1H), 6.46 (dd, J=8.2, 3.5Hz, 1H), 3.46 (d, J=3.4Hz, 3H).

[0145] Preparation of compound 8

[0146]

[0147] In a 250 mL reaction flask, 360 mg of lithium aluminum hydride was added to 20 mL of tetrahydrofuran, followed by 370 mg of a tetrahydrofuran solution of compound 7. The mixture was refluxed overnight at 110 °C. After the reaction was complete, the temperature was lowered to 0 °C, and 3 mL of water was slowly added with vigorous stirring, followed by 2 g of sodium bicarbonate. The mixture was then refluxed for another 3 hours. After the reaction solution cooled to room temperature, it was filtered through diatomaceous earth. The filter cake was washed with 20 mL of ethanol, and the filtrates were combined and concentrated under reduced pressure. The resulting solution was purified by column chromatography to obtain a yellow solid, 260 mg, in 82% yield.

[0148] Compound 8 data are as follows: ESI-HRMS m / z calcd C9H 14 NO2[M+H] + 168.1019, found 168.1035. 1H NMR (600MHz, DMSO) δ6.67(d,J=1.8Hz,1H),6.65(d,J=7.8Hz,1H),6.53(dd,J=8.0,1.8Hz,1H),3.75(s,4H),2.74(t,J=7.2Hz,2H),2.54(t,J=7.2Hz,2H).

[0149] Preparation of compound 9

[0150]

[0151] Method A: In a 50 mL reaction flask, 124 mg of p-methoxyphenylacetic acid was added to 6.7 mL of dichloromethane, followed by 160 mg of thionyl chloride and 0.1 mL of DMF. After reflux for 3 hours, the mixture was concentrated under reduced pressure to obtain the acyl chloride. 94 mg of compound 8 and 233 mg of potassium carbonate were dissolved in 4 mL of dichloromethane and 2 mL of water, and the dichloromethane solution of the acyl chloride was added dropwise. The reaction was carried out at room temperature for 2 hours. After the reaction was complete, 50 mL of dichloromethane was added, and the mixture was washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain a yellow solid, 178 mg, with a yield of 93%.

[0152] Method B: In a 10 mL reaction flask, 50 mg of p-methoxyphenylacetic acid, 50.2 mg of compound 8, 62.8 mg of EDCI, and 44.2 mg of HOBt were dissolved in 0.5 mL of N,N-dimethylformamide. The reaction was carried out overnight at room temperature. After the reaction was complete, 50 mL of dichloromethane was added, and the mixture was washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain a yellow solid, 10.4 mg, with a yield of 11%.

[0153] Method C: In a 10 mL reaction flask, 50 mg of p-methoxyphenylacetic acid, 50.2 mg of compound 8, 113.8 mg of HBTU, and 70.53 mg of DIPEA were dissolved in 1.0 mL of N,N-dimethylformamide and dichloromethane (1:1), and the mixture was reacted overnight at room temperature. After the reaction was complete, 50 mL of dichloromethane was added, and the mixture was washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain a yellow solid, 8.4 mg, in 9% yield.

[0154] Method D: In a 10 mL reaction flask, 18.4 mg of p-methoxyphenylacetic acid, 14 mg of compound 8 and 16.3 mg of CDI were dissolved in 0.8 mL of dichloromethane and reacted at room temperature for 3 hours. Reaction monitoring showed that no compound 9 was formed.

[0155] Reaction analysis: The reaction was difficult to proceed and the effect was poor when using EDCI, HBTU and CDI as condensing agents; p-methoxyphenylacetic acid was activated by SOCl2 to form an acyl chloride, which could undergo an amide condensation reaction with compound 8. The molar ratio of acyl chloride to compound 8 was 1.0 to 2.0:1, with 1.0:1 being preferred; the reaction temperature was 0℃ to room temperature, with room temperature being better.

[0156] Compound 9 data are as follows: ESI-HRMS m / z calcd C 18 H 22 NO4[M+H] + 316.1543, found 316.1580. 1 H NMR (600MHz, CDCl3) δ7.06-7.02(m,2H,Ar-H),6.83-6.80(m,2H,Ar-H),6.74(d,J=8.0Hz,1H,Ar-H),6.56(d,J=1.8Hz,1H,Ar-H),6.46(dd,J=8.0,1.8 Hz,1H,Ar-H),5.55(s,1H),5.35(s,1H),3.80(s,3H),3.79(s,3H),3.44(s, 2H,-CH2), 3.40(dd,J=12.8,6.8Hz,2H,-CH2), 2.63(t,J=6.9Hz,2H,-CH2). 13 C NMR (150MHz, CDCl3) δ171.6,159.0,146.8,144.4,130.7,130.6,126.9,121.5,114.6,114.5,111.2,56.1,55.5,43.1,40.9,35.3.

[0157] Preparation of compound 10

[0158]

[0159] In a 50 mL reaction flask, 456 mg of compound 9 was added to 7.2 mL of dichloromethane. Then, under nitrogen protection, 281 mg of difluoropyridine and 490 mg of trifluoromethanesulfonic anhydride were added, and the reaction was carried out at room temperature for 1 hour. After the reaction was complete, 50 mL of dichloromethane was added, and the mixture was washed twice with water. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain a yellow liquid, 387 mg, with a yield of 90%.

[0160] Compound 10 data are as follows: ESI-HRMS m / z calcd C 18 H 20 NO3[M+H] + 298.1438, found 298.1458.1 H NMR (500MHz, CDCl3) δ7.46 (s, 1H), 7.21 (d, J = 8.5Hz, 2H), 6.78 (d, J = 8.6Hz, 2H), 6. 75(s,1H),3.94(s,3H),3.86(t,J=8.3Hz,2H),3.70(s,3H),2.96(t,J=7.9Hz,2H). 13 C NMR (150MHz, CDCl3) δ174.9,159.4,154.2,145.9,132.8,130.3,125.1,121.7,119.6,118.1,115.8,114.9,110.9,56.6,55.4,42.6,39.0,25.5.

[0161] Preparation of the racemic mixture of compound 11

[0162]

[0163] In a 50 mL reaction flask, 200 mg of compound 10 was added to 3 mL of methanol, followed by the addition of 76.5 mg of sodium borohydride at 0 °C. The reaction was allowed to proceed for 1 hour at room temperature. After the reaction was complete, 1 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the reaction mixture was extracted with 50 mL of dichloromethane. The mixture was washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain 201 mg of the racemic mixture of compound 11, in 99% yield, as a yellow liquid.

[0164] The data for the racemic mixture of compound 11 are as follows: ESI-HRMS m / z calcd C 18 H 22 NO3[M+H] + 300.1594, found 300.1615. 1 H NMR (600MHz, CDCl3) δ7.12(d,J=8.4Hz,2H,Ar-H),6.83(d,J=8.4Hz,1H,Ar-H),6.74(s,1H,Ar-H),6.53(s,1 H,Ar-H),4.04(dd,J=9.7,3.4Hz,1H,NCH-),3.80(s,3H),3.77(s,3H),3.42(s,1H,-NH),3.20-3.14(m,1H,-C H 2),3.11(dd,J=13.9,3.7Hz,1H,-C H 2),2.87(dt,J=12.0,4.6Hz,1H,-C H 2),2.78(dd,J=13.8,9.8Hz,1H,-CH 2),2.74(dd,J=14.5,8.4Hz,1H,-C H 2),2.67(dt,J=15.9,5.4Hz,1H,-C H 2). 13 C NMR (150MHz, CDCl3) δ158.5,145.6,144.1,130.7,130.6,130.5,126.3,114.3,112.4,111.3,56.9,56.0,55.4,41.4,40.9,29.3. 13 C NMR (125MHz, DMSO) δ162.5,157.4,146.0,144.3,132.0,130.4,129.9,124.7,114.5,113.2,111.9,64.0,55.6,55.0,47.1,42.5,35.9,30.9,24.8.

[0165] Preparation of the racemic mixture of compound 12

[0166]

[0167] Method A (stepwise method): 150 mg of the racemic mixture of compound 11 was dissolved in methanol, 1 mL of formaldehyde was added, and 76.5 mg of sodium borohydride was slowly added at 0 °C. The reaction was allowed to proceed for 3 hours at room temperature. After the reaction was complete, 2 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the reaction was extracted with 100 mL of dichloromethane. The mixture was washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain 157.8 mg of the racemic mixture of compound 12, a yellow foamy solid, with a yield of 75%.

[0168] Method B (One-Pot Method): In a 50 mL reaction flask, 387 mg of compound 10 was added to 3 mL of methanol, followed by the addition of 148 mg of sodium borohydride at 0 °C. The reaction was allowed to proceed for 1 hour at room temperature. After the reaction was complete, 2 mL of formaldehyde was added, followed by the slow addition of 148 mg of sodium borohydride at 0 °C. The reaction was allowed to proceed for 3 hours at room temperature. After the reaction was complete, 2 mL of water was added to terminate the reaction. The mixture was concentrated under reduced pressure to remove methanol, and the reaction was extracted with 100 mL of dichloromethane. The mixture was washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain 338 mg of the racemic form of compound 12 as a yellow, foamy solid, with a yield of 83%.

[0169] Reaction analysis: After reduction with sodium borohydride, compound 10 can be directly reacted to obtain compound 12 without further treatment.

[0170] The data for the racemic mixture of compound 12 are as follows: 1H NMR(600MHz,DMSO)δ8.56(s,1H,-OH),7.06-7.01(m,2H,Ar-H),6.78-6.73(m,2H,Ar-H),6.55(s,1H,Ar-H),6.44(s, 1H,Ar-H),3.70(s,3H,-OCH3),3.69(s,3H,-OCH3),3.52(t,J=6.0Hz,1H,NCH-),3.04(ddd,J=12.6,8.1,5.0Hz,1H,-C H 2), 2.88-2.84(m,1H,-C) H 2),2.79(dd,J=14.4,5.0Hz,1H,-C H 2),2.63(ddd,J=15.5,8.0,5.1Hz,1H,-C H 2),2.54(dt,J=12.1,5.2Hz,1H,-C H 2),2.39(dt,J=15.8,5.0Hz,1H,-C H 2). 13 C NMR (125MHz, DMSO) δ162.5,157.4,146.0,144.3,132.0,130.4,129.9,124.7,114.5,113.2,111.9,64.0,55.6,55.0,47.1 42.5,35.9,30.9,24.8.

[0171] Preparation of the racemic mixture of compound 13

[0172]

[0173] Method A: 21.8 mg of compound 6, 23.5 mg of compound 12, 4.1 mg of a mixture of cuprous dimethyl sulfide bromide, 2.5 mg of 2-pyridinecarboxylic acid, and 21.2 mg of potassium phosphate were added to a 10 mL pressure tube. 0.5 mL of pyridine was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure to remove pyridine. The reaction was then extracted with 10 mL of dichloromethane, washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 28.5 mg of compound 13 as a yellow viscous liquid, with a yield of 86%.

[0174] Method B: 21.8 mg of compound 6, 23.5 mg of compound 12, 4.1 mg of a mixture of cuprous dimethyl sulfide bromide, 2.5 mg of 2-pyridinecarboxylic acid, and 32.6 mg of cesium carbonate (in the same molar amount as potassium phosphate) were added to a 10 mL pressure tube. 0.5 mL of pyridine was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure to remove pyridine. The reaction was then extracted with 10 mL of dichloromethane, washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 26.2 mg of compound 13 as a yellow viscous liquid, with a yield of 79%.

[0175] Method C: 21.8 mg of compound 6, 23.5 mg of compound 12, 4.1 mg of a mixture of cuprous dimethyl sulfide bromide, 1.0 mg of N,N-dimethylglycine (in the same molar amount as 2-pyridinecarboxylic acid), and 32.6 mg of cesium carbonate were added to a 10 mL pressure tube. 0.5 mL of pyridine was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure to remove pyridine. The reaction was then extracted with 10 mL of dichloromethane, washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 19.9 mg of compound 13 as a yellow viscous liquid, with a yield of 60%.

[0176] Method D: 21.8 mg of compound 6, 23.5 mg of compound 12, 20.5 mg of cuprous dimethyl sulfide bromide, and 48.9 mg of cesium carbonate were added to a 10 mL pressure tube. 0.5 mL of pyridine was added under anhydrous and oxygen-free conditions, followed by heating at 150 °C for 24 hours. After the reaction was complete, the mixture was concentrated under reduced pressure to remove pyridine. The reaction was then extracted with 10 mL of dichloromethane, washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 16.9 mg of compound 13 as a yellow viscous liquid, with a yield of 51%.

[0177] Method E: 21.8 mg of compound 6, 23.5 mg of compound 12, 4.1 mg of cuprous dimethyl sulfide bromide, and 32.6 mg of cesium carbonate were added to a 10 mL pressure tube. 0.5 mL of pyridine was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure to remove pyridine. The reaction was then extracted with 10 mL of dichloromethane, washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 4.2 mg of compound 13 as a yellow viscous liquid, with a yield of 25%.

[0178] Method F: 21.8 mg of compound 6, 23.5 mg of compound 12, 1.9 mg of cuprous iodide, 1.8 mg of 3,4,7,8-tetramethyl-1,10-phenanthroline, and 32.6 mg of cesium carbonate were added to a 10 mL pressure tube. 0.5 mL of acetonitrile was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 24 hours. After the reaction was complete, the mixture was concentrated under reduced pressure to remove acetonitrile. The reaction was then extracted with 10 mL of dichloromethane, washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 9.9 mg of compound 13 as a yellow viscous liquid, with a yield of 30%.

[0179] Method G: 21.8 mg of compound 6, 23.5 mg of compound 12, 1.9 mg of cuprous iodide, 4.0 mg of N1,N2 bis([1,1'-biphenyl]-2-yl)glyoxalamide, and 21.2 mg of potassium phosphate were added to a 10 mL pressure tube. 0.5 mL of LDM was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 24 hours. After the reaction was complete, the mixture was concentrated under reduced pressure, and 20 mL of dichloromethane was added for extraction. The mixture was washed twice with semi-saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 5.5 mg of compound 13 as a yellow viscous liquid, with a yield of 16%.

[0180] Method H: 21.8 mg of compound 6, 23.5 mg of compound 12, 1.9 mg of cuprous iodide, 1.0 mg of N,N-dimethylglycine, and 32.6 mg of cesium carbonate were added to a 10 mL pressure tube. 0.5 mL of 1,4-dioxane was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 24 hours. After the reaction was complete, the mixture was concentrated under reduced pressure to remove 1,4-dioxane. The reaction was then extracted with 10 mL of dichloromethane, washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 9.7 mg of compound 13 as a yellow viscous liquid, with a yield of 29%.

[0181] Method I: 21.8 mg of compound 6, 23.5 mg of compound 12, 1.9 mg of cuprous iodide, 2.5 mg of 2-pyridinecarboxylic acid, and 32.6 mg of cesium carbonate were added to a 10 mL pressure tube. 0.5 mL of DMSO was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 24 hours. After the reaction was complete, the mixture was concentrated under reduced pressure, and 20 mL of dichloromethane was added for extraction. The mixture was washed twice with semi-saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 2.7 mg of compound 13 as a yellow viscous liquid, with a yield of 8%.

[0182] Reaction Analysis: The novel method using CuBr·Me₂S as a catalyst, 2-pyridinecarboxylic acid as a ligand, potassium phosphate as a base, and pyridine as a solvent in the above reaction efficiently achieves intermolecular Ullmann coupling between compounds 6 and 12. The yield decreases when Cu₂O, CuBr, and CuI are used as catalysts; amounts between 10% and 100% equivalents are preferred, with 10%–20% equivalents showing better results. The effects are less pronounced when N,N-dimethylglycine, 3,4,7,8-tetramethyl-1,10-phenanthroline, N₁,N₂bis([1,1'-biphenyl]-2-yl)glyoxalamide, 2-pyridinecarboxylic acid·pyridinium salt, and N₁-(2-pyridinylmethylene)-N₂-(4-pyridinylmethylene)-1,2-cyclohexanediamine are used as ligands. The amount of ligand used is between 0.2 and 0.6 equivalents, preferably between 0.3 and 0.4 equivalents; cesium carbonate, cesium fluoride, and potassium carbonate are less effective than potassium phosphate when used as bases, and the amount used is between 2.0 and 3.0 equivalents, preferably between 2.0 and 2.5 equivalents; N,N-dimethylformamide, dimethyl sulfoxide, 1,4-dioxane, and pyridine can be used as reaction solvents, with pyridine being the best; the reaction temperature is preferably between 110 and 150°C, and the new method obtained through screening can maintain high reaction efficiency at a lower temperature of 110°C.

[0183] The data for the racemic mixture of compound 13 are as follows: ESI-HRMS m / z calcd C 40 H 49 N₂O₇[M+H] + 669.3534, found 669.3574. 1 H NMR(600MHz, CDCl3)δ7.05-7.01(m,1H),6.89(dd,J=15.6,7.8Hz,2H),6.68-6.63(m,3H),6.60(s,1H),6.51(s,0.5H),6.4 7(s,0.5H),6.31(s,1H),5.96(s,1H),5.15-5.12(m,2H),3.80(s,1.5H),3.78(s,1.5H),3.75(s,3H),3.69(s,3H),3.61(br s,2H),3.55(s,3H),3.42(s,3H),3.19-3.02(m,3H),3.01-2.91(m,1H),2.84-2.65(m,6H),2.63-2.51(m,2H),2.46(s,3H),2.44(s,3H). 13C NMR(100 MHz, CDCl3)δ158.0,149.4,147.7,147.7,147.6,147.6,146.6,145.9,131.3,131.1,130.7, 130.6,130.6,129.0,124.8,119.6,119.5,119.3,117.9,117.8,113.8,113.7,113.6,112.5, 111.3,111.2,111.1,110.8,95.9,68.3,64.8,64.6,56.2,56.0,55.9,55.9,55.7,55.35,55.3,47.2,46.4,42.6,42.1,40.8,40.2,40.0,38.9,30.5,29.9,29.1,25.9,24.9,23.9,23.1.

[0184] Preparation of racemic (±)-Nef of methylnepenone

[0185]

[0186] Method A: 20 mg of the racemic mixture of compound 11, 2 mL of methanol, and 1 mL of 0.2 M hydrochloric acid solution were added to a reaction flask and stirred overnight at room temperature. After the reaction was complete, the mixture was extracted with dichloromethane, washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 17.2 mg of the racemic mixture of methylnepenem, with a yield of 87%.

[0187] Method B: 180 mg of racemic compound 11, 2 mL of methanol, and 1 mL of trifluoroacetic acid were added to a reaction flask and stirred at room temperature for 24 h. After the reaction was complete, the mixture was concentrated under reduced pressure and purified by column chromatography to obtain 158 mg, with a yield of 94%.

[0188] The data for methylnephrine are as follows: ESI-HRMS m / z calcd C 38 H 45 N₂O₆[M+H] + 625.3272, found 625.3293.

[0189] The proton and carbon NMR spectra of the racemic mixture (±)-Nef of methylnepenem are as follows: Figure 1 and Figure 2 As shown.

[0190] Implementation Case 2: Chiral Synthesis of Methylnephrine

[0191] Preparation of compound R-4

[0192]

[0193] In a 50 mL reaction flask, 2.5 g of compound 3 and 42.3 mg of ruthenium catalyst RuCl [(S,S)-TsDPEN(P-cymene)] were added to 6.6 mL of N,N-dimethylformamide. Then, 0.83 mL of a formic acid-triethylamine (5:2) azeotrope was added at 0 °C, and the reaction was allowed to proceed overnight at room temperature. After the reaction was complete, 200 mL of dichloromethane was added for extraction. The mixture was washed with semi-saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain 2.28 g of compound R-4, a brown viscous liquid, with a yield of 91% and an ee value of 93%. (ESI-HRMSm / z calcd C) 18 H 21 BrNO3[M+H] + 378.0699, found 378.0705. [α] D 25 -15.4 (c 0.24, MeOH); 1 H NMR (600MHz, DMSO) δ10.37(s,1H,-OH),7.62(d,J=2.0 Hz,1H,Ar-H),7.56(s,1H,Ar-H),7.19(dd,J=8.4,2.0 Hz,1H,Ar-H),7.13(s,1H,Ar-H),6.91(d,J=8.4 Hz,1H,Ar-H),4.41(s,2H,-CH2Ph),3.89(s,3H,-OCH3),3.83-3.79(m,5H,-OCH3,-NCH2),3.01(t,J=8.0 Hz,1H,-CH2).

[0194] Preparation of compound R-4 hydrochloride

[0195]

[0196] 2.28 g of compound R-4 was dissolved in 5 mL of THF, followed by the addition of 2 mL of ether solution in 2.0 M HCl. After thorough mixing, the mixture was placed in a -20°C freezer for 2 days. A white solid precipitated at the bottom. Filtration yielded 1.7 g of R-4 hydrochloride as a white solid powder, with a yield of 70%. ESI-HRMS m / z calcd C 18 H 21 BrNO3[M-Cl] + 378.0699, found 378.0711. [α] D 25 -17.7 (c 0.31, MeOH); 1H NMR (500MHz, DMSO) δ9.30(s,1H),9.21(s,1H),7.95(s,1H),7.52(d,J=2.0Hz,1H),7.18(dd,J= 8.3,2.0Hz,1H),6.97(d,J=8.2Hz,1H),6.78(s,1H),6.64(s,1H),4.56(s,1H),3.73(s,3H),3.6 2(s,3H),3.36(td,J=12.0,5.5Hz,1H),3.28(dd,J=14.1,6.0Hz,1H),3.17(td,J=11.8,5.5Hz,1 H),3.07(dd,J=14.1,8.3Hz,1H),3.00(dt,J=16.8,5.9Hz,1H),2.93-2.83(m,4H),2.73(s,3H).

[0197] Preparation of compound R-5

[0198]

[0199] In a 50 mL reaction flask, 2.1 g of compound R-4 hydrochloride was added to 10 mL of methanol, followed by 1.1 mL of formaldehyde. 419 mg of sodium borohydride was slowly added at 0 °C, and the reaction was allowed to proceed for 3 hours at room temperature. After the reaction was complete, 5 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the reaction mixture was extracted with 100 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to give 1.94 g of compound R-5 as a white solid, with a yield of 89%. ESI-HRMS m / z calcdC 19 H 23 BrNO3[M+H] + 392.0856, found 392.0879.[α] D 25 -9.8 (c 0.21, MeOH);

[0200] Preparation of compound R-6

[0201]

[0202] Method A (stepwise method): In a 100 mL reaction flask, 1.9 g of compound R-5 was added to 23.8 mL of tetrahydrofuran, followed by 194 mg of sodium hydride. 606 mg of MOMBr was slowly added at 0 °C, and the reaction was allowed to proceed for 10 minutes at room temperature. After the reaction was complete, 2 mL of water was added to terminate the reaction. The tetrahydrofuran was removed by concentration under reduced pressure, and the reaction was extracted with 200 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and separated by column chromatography to obtain 1.56 g of compound R-6, a light brown foamy solid, with a yield of 74%. ESI-HRMS m / z calcd C 21 H 27 BrNO4[M+H] + 436.1118, found 436.1146.[α] D 25 -40.5 (c 1.2, CHCl3); 1 H NMR (500MHz, CDCl3) δ7.31(d,J=2.0Hz,1H),7.00(d,J=8.4Hz,1H),6.93(dd,J=8.4,2 .0Hz,1H),6.54(s,1H),6.07(s,1H),5.18(s,2H),3.82(s,3H),3.65-3.62(m,1H),3. 60(s,3H),3.48(s,3H),3.15(ddd,J=12.7,8.8,5.1Hz,1H),3.06(dd,J=13.8,5.5Hz, 1H),2.85-2.77(m,1H),2.76-2.70(m,2H),2.55(dt,J=15.7,4.5Hz,1H),2.49(s,3H).

[0203] Method B (One-Pot Method): In a 50 mL reaction flask, 1.65 g of compound 3 and 27.9 mg of ruthenium catalyst RuCl [(S,S)-TsDPEN(P-cymene)] were added to 4.4 mL of N,N-dimethylformamide. Then, 0.55 mL of a formic acid-triethylamine (5:2) azeotrope was added at 0 °C, and the reaction was allowed to proceed overnight at room temperature. After the reaction was complete, 200 mL of dichloromethane was added for extraction, and the mixture was concentrated under reduced pressure to obtain crude compound R-4. 4.5 mL of methanol and 0.87 mL of formaldehyde were added to crude R-4, and 331 mg of sodium borohydride was slowly added at 0 °C. The reaction was allowed to proceed for 1 hour at room temperature. After the reaction was complete, 5 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the mixture was extracted with 100 mL of dichloromethane. After drying, filtration, and concentration under reduced pressure, a brown, foamy crude product R-5 was obtained. 22 mL of tetrahydrofuran was added to crude R-5, followed by 175 mg of sodium hydride under nitrogen protection. Then, 548 mg of MOMBr was slowly added at 0 °C, and the reaction was allowed to proceed for 5 minutes at room temperature. After the reaction was complete, 2 mL of water was added to terminate the reaction. The tetrahydrofuran was removed by concentration under reduced pressure, and the mixture was extracted with 200 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and separated by column chromatography to obtain 691 mg of compound R-6 as a brown, foamy solid, with a total yield of 36%.

[0204] Reaction analysis: Starting with compound 3, the three-step reaction (asymmetric reduction, N-methylation and methoxymethyl ether protection) can be integrated into a one-step reaction without column chromatography purification to obtain compound R-6.

[0205] Preparation of compound R-11

[0206]

[0207] In a 25 mL reaction flask, 1.5 g of compound 10 and 32.0 mg of ruthenium catalyst RuCl [(R,R)-TsDPEN(P-cymene)] were added to 8.0 mL of N,N-dimethylformamide. Then, 625 μL of a formic acid-triethylamine (5:2) azeotrope was added at 0 °C, and the reaction was allowed to proceed overnight at room temperature. After the reaction was complete, 100 mL of dichloromethane was added for extraction. The mixture was washed with semi-saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to give 1.36 g of compound R-11 as a brown solid, with a yield of 90%. (ESI-HRMS m / z calcd C) 18 H 22 NO3[M+H] + 300.1594, found 300.1600.

[0208] Preparation of compound R-11 hydrochloride

[0209]

[0210] 1.36 g of compound R-11 was dissolved in 5 mL of THF, followed by the addition of 2 mL of ether solution in 2.0 M HCl. After thorough mixing, the mixture was placed in a -20°C freezer for 2 days. A solid precipitated at the bottom, which was filtered to obtain 627 mg of R-11 hydrochloride as a light yellow solid powder, with a yield of 42%. ESI-HRMS m / z calcd C 18 H 22 NO3[M-Cl] + 300.1594, found 300.1600.[α] D 25 +6.1 (c 0.41, MeOH); 1 H NMR (500MHz, DMSO) δ9.25(s,2H),8.94(s,1H),7.28(d,J=8.6Hz,2H),6.92(d,J=8.7Hz,2H),6.75(s,1H),6.56(s,1H),4.60-4.50(m,1 H),3.76(s,6H),3.34-3.27(m,1H),3.21(dd,J=14.3,6.1Hz,1H),3.18-3.09(m,2H),2.99(dt,J=16.4,6.0Hz,1H),2.91-2.81(m,1H).

[0211] Preparation of compound R-12

[0212]

[0213] Method A (stepwise method): In a 50 mL reaction flask, 500 mg of compound R-11 hydrochloride was added to 3.5 mL of methanol, followed by 0.3 mL of formaldehyde. 100 mg of sodium borohydride was slowly added at 0 °C, and the reaction was allowed to proceed for 3 hours at room temperature. After the reaction was complete, 2 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the reaction was extracted with 100 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 470 mg of compound R-5 as a white solid, with a yield of 96%. ESI-HRMS m / z calcd C 19 H 24 NO3 + [M+H] + 314.1751, found 314.1778. [α] D 25 -49.6 (c 0.51, CHCl3); 1H NMR(500MHz, CDCl3)δ7.02(d,J=8.5Hz,2H),6.77(d,J=8.6Hz,2H),6.51(s ,1H),6.39(s,1H),3.83(s,3H),3.76(s,3H),3.63(t,J=6.0Hz,1H),3.13(d dd,J=13.0,8.1,5.1Hz,1H),3.01(dd,J=14.2,6.2Hz,1H),2.82(dd,J=14. 2,6.0Hz,1H),2.78-2.66(m,2H),2.52(dt,J=8.6,4.5Hz,1H),2.43(s,3H).

[0214] Method B (One-Pot Method): In a 50 mL reaction flask, 912 mg of compound 10 and 19.5 mg of ruthenium catalyst RuCl [(S,S)-TsDPEN(P-cymene)] were added to 3.0 mL of N,N-dimethylformamide. Then, 385 μL of a formic acid-triethylamine (5:2) azeotrope was added at 0 °C, and the reaction was allowed to proceed overnight at room temperature. After the reaction was complete, 100 mL of dichloromethane was added for extraction, and the mixture was concentrated under reduced pressure to obtain crude compound R-11. 3.5 mL of methanol and 0.47 mL of formaldehyde were added to crude R-11, and 174 mg of sodium borohydride was slowly added at 0 °C. The reaction was allowed to proceed for 1 hour at room temperature. After the reaction was complete, 5 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the mixture was extracted with 100 mL of dichloromethane. After drying, filtration, and concentration under reduced pressure, the mixture was separated by column chromatography to obtain 721 mg of compound R-12, a brown foamy solid, with a total yield of 75%.

[0215] Reaction analysis: Starting with compound 10, the two-step reaction (asymmetric reduction and N-methylation) can be integrated into a one-step reaction without column chromatography purification to obtain compound R-12.

[0216] Preparation of compound (R,R)-13

[0217]

[0218] Method A: 520 mg of compound R-6, 560 mg of compound R-12, 48.7 mg of a mixture of cuprous dimethyl sulfide bromide, 58.7 mg of 2-pyridinecarboxylic acid, and 505 mg of potassium phosphate were added to a 10 mL Schlenk tube. Under anhydrous and anaerobic conditions, 23.8 mL of pyridine was added, followed by heating at 110 °C for 5 days. After the reaction was complete, the mixture was concentrated under reduced pressure to remove pyridine. The reaction was then extracted with 200 mL of dichloromethane, washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 661 mg of compound (R,R)-13, a brown viscous liquid, with a yield of 83%. ESI-HRMS m / z calcd C 40 H 49 N₂O₇[M+H] + 669.3534, found 669.3564.[α] D 25 -118 (c 0.4, CHCl3); 1 H NMR (400MHz, CDCl3) δ7.03(d,J=8.2Hz,1H),6.87(d,J=8.4Hz,2H),6.68-6.67(m,3H),6.6 0(s,1H),6.53(d,J=1.2Hz,1H),6.47(s,1H),6.29(s,1H),5.94(s,1H),5.13(q,J=6.6Hz, 2H),3.78(s,3H),3.75(s,3H),3.69(s,3H),3.66-3.61(m,2H),3.54(s,3H),3.42(s,3H), 3.18-3.10(m,2H),3.00-3.97(m,1H),2.86-2.71(m,6H),2.71-2.60(m,3H),2.49(s,6H). 13 C NMR (125MHz, CDCl3) δ158.0,149.4,147.6,146.7,145.9,143.3,130.6,124.8,119.6,119.3,117.8,113.6,112.6,111.4 ,111.2,95.9,64.7,64.6,56.2,56.0,55.9,55.7,55.3,47.3,46.4,42.6,40.8,40.0,31.7,31.6,30.3,29.9,26.0,25.0.

[0219] Preparation of methylnephrine Nef

[0220]

[0221] 661 mg of compound (R,R)-13, 5 mL of methanol, and 2.5 mL of trifluoroacetic acid were added to a reaction flask and stirred at room temperature for 1 day. After the reaction was complete, the mixture was concentrated under reduced pressure and purified by column chromatography to obtain 525 mg of methylnepenone Nef as a yellow solid powder, with a yield of 85%. The chromatographic data of methylnepenone (R,R)-Nef are as follows: ESI-HRMS m / z calcd C 38 H 45 N₂O₆[M+H] + 625.3272, found 625.3297.[α] D 25 -22.0 (c 1.56, CHCl3); 1 H NMR (500MHz, CDCl3) δ6.88(d,J=8.5Hz,2H),6.83(d,J=8.2Hz,1H),6.71-6.65(m,3H),6.61(s,1H),6.53(d,J=1.6 Hz,1H),6.48(s,1H),6.37(s,1H),5.98(s,1H),3.79(s,3H),3.78(s,3H),3.71(s,3H),3.65-3.57(m,2H),3.51(s ,3H),3.15-3.08(m,2H),3.03(dd,J=13.7,5.0Hz,1H),2.97(dd,J=14.0,5.4Hz,1H),2.82-2.74(m,3H),2.73-2.6 8(m,2H),2.65(dd,J=13.7,7.8Hz,1H),2.59(dt,J=15.6,4.7Hz,1H),2.55-2.49(m,1H),2.47(s,3H),2.44(s,3H). 13 C NMR (125MHz, CDCl3) δ158.1,149.2,147.5,146.6,145.7,145.0,143.1,132.1,131.6,131.7,130.7,129.3,125.9,125.6,120.3 ,119.6,115.6,113.7,112.6,111.4,111.2,65.0,64.6,56.1,56.0,55.7,55.4,47.4,46.9,42.9,42.7,40.9,40.1,26.4,25.4.

[0222] The proton and carbon NMR spectra of methylnephrine (R,R)-Nef are as follows: Figure 3 and Figure 4 As shown.

[0223] Implementation Case 3: Chiral Synthesis of the Chiral Isomer (R,S)-Nef of Methylnephrine

[0224] Preparation of compound S-11

[0225]

[0226] In a 50 mL reaction flask, 2.4 g of compound 10 and 51.3 mg of ruthenium catalyst RuCl [(R,R)-TsDPEN(P-cymene)] were added to 8.0 mL of N,N-dimethylformamide. Then, 1.0 mL of a formic acid-triethylamine (5:2) azeotrope was added at 0 °C, and the reaction was allowed to proceed overnight at room temperature. After the reaction was complete, 200 mL of dichloromethane was added for extraction. The mixture was washed with semi-saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain 2.3 g of compound S-11 as a brown solid, with a yield of 96% and an ee value of 91%. (ESI-HRMS m / z calcd C) 18 H 22 NO3[M+H] + 300.1594, found 300.1611.[α] D 25 -12.5 (c 0.28, MeOH);

[0227] Preparation of compound S-11 hydrochloride

[0228]

[0229] 2.3 g of compound S-11 was dissolved in 5 mL of THF, followed by the addition of 2 mL of ether solution in 2.0 M HCl. After thorough mixing, the mixture was placed in a -20°C freezer and allowed to stand for 2 days. A solid precipitated at the bottom; after filtration, 1.33 g of S-11 hydrochloride was obtained as a light yellow solid powder, with a yield of 52%. ESI-HRMS m / z calcd C 18 H 22 NO3[M+H] + 300.1594, found 300.1613.[α] D 25 -5.8 (c 0.45, CHCl3); 1H NMR(500MHz, CDCl3)δ9.15(d,J=19.5Hz,2H),8.93(s,1H),7.27(d,J=8.6Hz,2H), 6.92(d,J=8.6Hz,2H),6.75(s,1H),6.55(s,1H),4.54(s,1H),3.75(s,6H),3.32- 3.28(m,1H),3.21(dd,J=14.3,6.0Hz,1H),3.15(dd,J=12.0,6.5Hz,1H),3.10(dd ,J=14.3,7.8Hz,1H),2.97(dt,J=16.4,6.0Hz,1H),2.85(dt,J=16.6,6.0Hz,1H).

[0230] Preparation of compound S-12

[0231]

[0232] Method A (stepwise method): In a 50 mL reaction flask, 1.06 g of compound S-11 hydrochloride was added to 7 mL of methanol, followed by 0.53 mL of formaldehyde. 200 mg of sodium borohydride was slowly added at 0 °C, and the reaction was allowed to proceed for 3 hours at room temperature. After the reaction was complete, 5 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the reaction was extracted with 100 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 969 mg of compound S-12 as a white solid, with a yield of 98%. ESI-HRMS m / z calcd C 19 H 24 NO3 + [M+H] + 314.1751, found 314.1778. [α] D 25 +52.1 (c 1.0, CHCl3); 1 H NMR (500MHz, CDCl3) δ7.04(d,J=8.6Hz,2H),6.81-6.75(m,2H),6.53(s,1H),6.40(s,1H),3.85(s,3H),3.78(s,3H),3.66(t,J=6.0Hz, 1H),3.19-3.12(m,1H),3.05(dd,J=14.2,6.1Hz,1H),2.84(dd,J=14.2,6.0Hz,1H),2.80-2.69(m,2H),2.60-2.51(m,1H),2.46(s,3H).

[0233] Method B (One-Pot Method): In a 50 mL reaction flask, 1.4 mg of compound 10 and 29.9 mg of ruthenium catalyst RuCl [(R,R)-TsDPEN(P-cymene)] were added to 4.7 mL of N,N-dimethylformamide. Then, 591 μL of a formic acid-triethylamine (5:2) azeotrope was added at 0 °C, and the reaction was allowed to proceed overnight at room temperature. After the reaction was complete, 100 mL of dichloromethane was added for extraction, and the mixture was concentrated under reduced pressure to obtain crude compound S-11. 4.5 mL of methanol and 0.71 mL of formaldehyde were added to the crude S-11, and 267 mg of sodium borohydride was slowly added at 0 °C. The reaction was allowed to proceed for 1 hour at room temperature. After the reaction was complete, 5 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the mixture was extracted with 100 mL of dichloromethane. After drying, filtration, and concentration under reduced pressure, the mixture was separated by column chromatography to obtain 1.06 g of compound S-12, a brown foamy solid, with a total yield of 72%.

[0234] Reaction analysis: Starting with compound 10, the two-step reaction (asymmetric reduction and N-methylation) can be integrated into a one-step reaction without column chromatography purification to obtain compound S-12.

[0235] Preparation of compound (R,S)-13

[0236]

[0237] Method A: 891 mg of compound R-6, 960 mg of compound S-12, 83.9 mg of a mixture of cuprous dimethyl sulfide bromide, 100.6 mg of 2-pyridinecarboxylic acid, and 867.0 mg of potassium phosphate were added to a 200 mL Schlenk flask. 41 mL of pyridine was added under anhydrous and oxygen-free conditions, followed by heating at 110 °C for 7 days. After the reaction was complete, the pyridine was removed by vacuum concentration. The reaction was then extracted with 200 mL of dichloromethane, washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography to obtain 1.2 g of compound (R,S)-13, a brown viscous liquid, with a yield of 88%. ESI-HRMS m / z calcd C 40 H 49 N₂O₇[M+H] + 669.3534, found 669.3559.[α] D 25 -63.3 (c 0.1, CHCl3); 1H NMR(500MHz, CDCl3)δ7.02(d,J=8.2Hz,1H),6.92(d,J=8.1Hz,2H),6.68-6.59(m,4H),6.56(s,1 H),6.52(s,1H),6.14(s,1H),5.76(s,1H),5.15-5.08(m,2H),3.98-3.88(m,2H),3.82(s,3H),3 .77(s,3H),3.69(s,3H),3.61-3.53(m,1H),3.48(s,3H),3.41(s,3H),3.38-3.29(m,2H),3.14- 3.07(m,1H),3.04-2.90(m,4H),2.89-2.79(m,4H),2.76-2.71(m,1H),2.68(s,3H),2.67(s,3H). 13 C NMR (126MHz, CDCl3) δ158.5,150.2,148.9,147.5,147.3,146.6,130.9,125.4,120.0,119.3,118.2,116.2,116.2,114.0,112.7 ,111.5,111.4,95.9,65.2,64.8,56.3,56.1,55.8,55.4,46.6,45.5,41.7,40.8,40.7,40.2,31.8,30.3,29.9,29.5,23.0,22.9.

[0238] Preparation of the chiral isomer (R,S)-Nef of methylnepenone

[0239]

[0240] 1.2 g of compound (R,S)-13, 10 mL of methanol, and 5 mL of trifluoroacetic acid were added to a reaction flask and stirred at room temperature for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure and purified by column chromatography to obtain 1.07 g of the chiral isomer of methylnepenthes (R,S)-Nef, a yellow solid powder, with a yield of 95%. The chromatographic data of (R,S)-Nef are as follows: ESI-HRMS m / z calcd C 38 H 45 N₂O₆[M+H] + 625.3272, found 625.3298.[α] D 25 -20.0 (c 1.55, CHCl3); [α] D 25 -21.5 (c 1.66, CHCl3); 1HNMR(400MHz, CDCl3) δ6.90(d,J=8.6Hz,2H),6.82(d,J=8.2Hz,1H),6.66(dd,J=12.6,5.2Hz,3H),6.6 2(s,1H),6.55(d,J=1.8Hz,1H),6.50(s,1H),6.37(s,1H),6.00(s,1H),3.80(s,3H),3.77(s,3H),3.70 (s,3H),3.59(dd,J=13.5,7.3Hz,2H),3.53(s,3H),3.17-3.06(m,2H),3.01(td,J=13.9,5.3Hz,2H),2 .85-2.73(m,3H).,2.73-2.67(m,2H),2.66-2.57(m,2H),2.57-2.49(m,1H),2.46(s,3H),2.43(s,3H). 13 C NMR (101MHz, CDCl3) δ158.0,149.2,147.5,146.6,145.6,144.9,143.0,132.2,131.7,131.2,130.7,130.6,129.4,125.9,125.5,12 0.2,119.4,115.7,113.7,112.6,111.4,111.2,65.0,64.7,56.1,55.9,55.7,55.3,47.3,47.0,42.9,42.7,40.9,40.2,26.3,25.5.

[0241] The proton and carbon NMR spectra of the chiral isomer (R,S)-Nef of methylnephrine are as follows: Figure 5 and Figure 6 As shown.

[0242] Implementation Case 4: Synthesis of the chiral isomer (S,R)-Nef of methylnepenone

[0243] Preparation of compound S-4

[0244]

[0245] In a 10 mL reaction flask, 300 mg of compound 3 and 5.0 mg of ruthenium catalyst RuCl [(S,S)-TsDPEN(P-cymene)] were added to 1.0 mL of N,N-dimethylformamide. Then, 100 μL of a formic acid-triethylamine (5:2) azeotrope was added at 0 °C, and the reaction was allowed to proceed overnight at room temperature. After the reaction was complete, 200 mL of dichloromethane was added for extraction. The mixture was washed with semi-saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and then subjected to column chromatography to obtain 256 mg of compound S-4, a brown viscous liquid, with a yield of 85% and an ee value of 93%. (ESI-HRMS m / z calcd C) 18 H 21 BrNO3[M+H] + 378.0699, found 378.0703. 1 HNMR (600MHz, DMSO) δ10.37(s,1H,-OH),7.62(d,J=2.0Hz,1H,Ar-H),7.56(s,1H,Ar-H),7.19(dd,J=8.4,2.0Hz,1H,Ar-H),7.13(s,1H,Ar- H),6.91(d,J=8.4Hz,1H,Ar-H),4.41(s,2H,-CH2Ph),3.89(s,3H,-OCH3),3.83-3.79(m,5H,-OCH3,-NCH2),3.01(t,J=8.0Hz,1H,-CH2).[α] D 25 -7.9 (c 0.63, CHCl3);

[0246] Preparation of compound S-4 hydrochloride

[0247]

[0248] 256 mg of compound S-4 was dissolved in 2 mL of THF, followed by the addition of 1 mL of ether solution in 2.0 M HCl. After thorough mixing, the mixture was placed in a -20°C freezer for 2 days. A white solid precipitated at the bottom. Filtration yielded 116 mg of S-4 hydrochloride as a white solid powder, with a yield of 43%. ESI-HRMS m / z calcd C 18 H 21 BrNO3[M-Cl] + 378.0699, found 378.0716. [α] D 25 -49.6 (c0.51, CHCl3);

[0249] Preparation of compound S-5

[0250]

[0251] In a 5 mL reaction flask, 116 mg of compound S-4 hydrochloride was added to 2 mL of methanol, followed by 46 μL of formaldehyde. 18.0 mg of sodium borohydride was slowly added at 0 °C, and the reaction was allowed to proceed for 3 hours at room temperature. After the reaction was complete, 1 mL of water was added to terminate the reaction. The methanol was removed by concentration under reduced pressure, and the reaction mixture was extracted with 50 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 116 mg of compound S-5 as a white solid, with a yield of 96%. ESI-HRMS m / z calcdC 19 H 23 BrNO3[M+H] + 392.0856, found 392.0864.[α] D 25 +7.5 (c 0.54, MeOH);

[0252] Preparation of compound S-6

[0253]

[0254] In a 100 mL reaction flask, 116 mg of compound S-5 was added to 1.5 mL of tetrahydrofuran, followed by 11.8 mg of sodium hydride. 37 mg of MOMBr was slowly added at 0 °C, and the reaction was allowed to proceed for 10 minutes at room temperature. After the reaction was complete, 0.5 mL of water was added to terminate the reaction. The tetrahydrofuran was removed by concentration under reduced pressure, and the mixture was extracted with 50 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and separated by column chromatography to obtain 83.6 mg of compound S-6 as a white, foamy solid, with a yield of 65%. ESI-HRMS m / z calcd C 21 H 27 BrNO4[M+H] + 436.1118, found 436.1143.[α] D 25 +47.1 (c 0.56, CHCl3);

[0255] Preparation of compound (S,R)-13

[0256]

[0257] In a 10 mL Schlenk flask, 21.8 mg of compound S-6, 23.5 mg of compound R-12, 2.1 mg of a mixture of cuprous dimethyl sulfide bromide, 2.5 mg of 2-pyridinecarboxylic acid, and 21.2 mg of potassium phosphate were added. Under anhydrous and oxygen-free conditions, 0.5 mL of pyridine was added, followed by heating at 110 °C for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure to remove pyridine, and the reaction was extracted with 50 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 24.4 mg of compound (R,S)-13, a brown viscous liquid, with a yield of 78%. ESI-HRMS m / z calcd C 40 H 49 N₂O₇[M+H] + 669.3534, found 669.3543.[α] D 25 +57.5 (c 0.2, CHCl3); 1 H NMR(500MHz, CDCl3)δ7.05(d,J=8.2Hz,1H),6.95(d,J=8.0Hz,2H),6.72-6.63(m,4H),6 .60(s,1H),6.56(s,1H),6.13(s,1H),5.76(s,1H),5.16-5.10(m,2H),4.07-4.02(m,1H) ,4.01-3.96(m,1H),3.86(s,3H),3.80(s,3H),3.72(s,3H),3.68-3.64(m,1H),3.50(s, 3H),3.43(s,3H),3.40-3.37(m,1H),3.21-3.16(m,1H),3.14-3.09(m,1H),3.07-2.96(m 3H),2.96-2.84(m,5H),2.73(br s,7H). 13 C NMR (125MHz, CDCl3) δ158.6,150.3,149.0,147.5,147.4,146.6,143.8,1 30.9,125.5,124.1,123.7,120.0,119.3,118.1,116.2,114.1,112.7,111 .5,111.4,95.8,65.2,64.8,56.3,56.2,56.1,55.7,55.4,46.5,45.4,41. 5,41.5,40.6,40.1,34.9,34.4,32.1,31.8,29.9,29.9,29.5,24.0,22.7.

[0258] Preparation of the chiral isomer (S,R)-Nef of methylnepenone

[0259]

[0260] 24.4 mg of compound (S,R)-13, 1 mL of methanol, and 0.5 mL of trifluoroacetic acid were added to a reaction flask and stirred at room temperature for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure and purified by column chromatography to obtain 17.3 mg of the chiral isomer of methylnepenone (S,R)-Nef, a yellow solid powder, with a yield of 76%. The chromatographic data of the chiral isomer of methylnepenone (S,R)-Nef are as follows: ESI-HRMS m / z calcd C 38 H 45 N₂O₆[M+H] + 625.3272, found 625.3297.[α] D 25 -19.8 (c 0.44, CHCl3); 1 H NMR (400MHz, CDCl3) δ6.93(d,J=8.6Hz,2H),6.85(d,J=8.2Hz,1H),6.72-6.66(m,3H),6.64(s,1 H),6.56(d,J=1.9Hz,1H),6.53(s,1H),6.37(s,1H),5.98(s,1H),3.82(s,3H),3.80(s,3H),3.72 (s,3H),3.66-3.62(m,2H),3.54(s,3H),3.20-3.08(m,3H),3.04(dd,J=13.9,5.4Hz,1H),2.88- 2.77(m,3H),2.76-2.71(m,2H),2.70-2.62(m,2H),2.62-2.56(m,1H),2.49(s,3H),2.48(s,3H). 13 C NMR (101MHz, CDCl3) δ158.1,149.2,147.6,146.6,145.7,144.9,143.0,131.8,131.5,131.1,130.6,130.5,125.6,120.2,11 9.4,115.7,113.7,112.6,111.3,111.2,65.0,64.7,56.1,55.9,55.7,55.3,47.2,46.8,42.8,42.5,40.8,40.1,26.1,25.2.

[0261] The proton and carbon NMR spectra of the chiral isomer (S,R)-Nef of methylnephrine are shown below. Figure 7 and Figure 8 As shown.

[0262] Implementation Case 5: Synthesis of the chiral isomer (S,S)-Nef of methylnepenone

[0263] Preparation of compound (S,S)-13

[0264]

[0265] In a 10 mL Schlenk flask, 21.8 mg of compound S-6, 23.5 mg of compound R-12, 2.1 mg of a mixture of cuprous dimethyl sulfide bromide, 2.5 mg of 2-pyridinecarboxylic acid, and 21.2 mg of potassium phosphate were added. Under anhydrous and oxygen-free conditions, 0.5 mL of pyridine was added, followed by heating at 110 °C for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure to remove pyridine, and the reaction was extracted with 50 mL of dichloromethane. The mixture was washed twice with water, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography to obtain 23.4 mg of compound (S,S)-13, a brown viscous liquid, with a yield of 73%. ESI-HRMS m / z calcd C 40 H 49 N₂O₇[M+H] + 669.3534, found 669.3549.[α] D 25 +124 (c 0.15, CHCl3); 1 H NMR(500MHz, CDCl3) δ7.02(d,J=8.1Hz,1H),6.89(d,J=8.0Hz,2H),6.65(dd,J=12.1,4.2Hz,4H) ,6.51(s,2H),6.18(s,1H),5.78(s,1H),5.18-5.06(m,2H),3.98-3.88(m,2H),3.80(s,3H),3.76 (s,3H),3.69(s,3H),3.60-3.53(m,1H),3.49(s,3H),3.41(s,3H),3.35-3.26(m,2H),3.08(ddd ,J=10.6,9.6,4.2Hz,1H),3.05-2.94(m,3H),2.90-2.80(m,3H),2.78-2.72(m,2H),2.67(s,6H). 13C NMR (125MHz, CDCl3) δ158.5,150.3,148.8,147.8,147.2,146.5,143.6,130.9,125.3,124.2,123.7,119.8,119.6,118.0,114.0,112.8 ,111.4,111.3,95.9,65.2,64.7,56.3,56.1,56.1,55.8,55.4,46.6,45.7,41.6,41.0,40.7,39.8,32.1,31.8,29.9,29.6,23.2,22.9.

[0266] Preparation of the chiral isomer (S,S)-Nef of methylnepenone

[0267]

[0268] 23.4 mg of compound (S,S)-13, 1 mL of methanol, and 0.5 mL of trifluoroacetic acid were added to a reaction flask and stirred at room temperature for 3 days. After the reaction was complete, the mixture was concentrated under reduced pressure and purified by column chromatography to obtain 18.1 mg of the chiral isomer of methylnepenone (S,R)-Nef, a yellow solid powder, with a yield of 83%. The chromatographic data of the chiral isomer of methylnepenone (S,S)-Nef are as follows: ESI-HRMS m / z calcd C 38 H 45 N₂O₆[M+H] + 625.3272, found 625.3287.[α] D 25 +18.3 (c 0.8, CHCl3); 1 H NMR (400MHz, CDCl3) δ6.91(d,J=8.6Hz,2H),6.85(d,J=8.2Hz,1H),6.72-6.68(m,3H),6.63(s,1H),6.55( d,J=1.9Hz,1H),6.38(s,1H),6.00(s,1H),3.81(s,3H),3.80(s,3H),3.73(s,3H),3.63(dt,J=7.6,5.5Hz ,2H),3.53(s,3H),3.18-3.10(m,2H),3.06(dd,J=13.7,5.2Hz,1H),3.00(dd,J=14.0,5.4Hz,1H),2.86-2 .77(m,3H),2.73(dd,J=11.2,6.2Hz,2H),2.70-2.63(m,2H),2.61-2.54(m,1H),2.50(s,3H),2.46(s,3H). 13C NMR (101MHz, CDCl3) δ158.1,149.1,147.5,146.6,145.7,144.9,143.1,132.1,131.6,131.4,130.7,129.2,125.9,125.6,120.3 ,119.6,115.6,113.7,112.6,111.4,111.2,65.0,64.6,56.1,55.9,55.7,55.4,47.4,46.9,42.9,42.7,40.9,40.1,26.3,25.4.

[0269] The proton and carbon NMR spectra of the chiral isomer (S,S)-Nef of methylnephrine are as follows: Figure 9 and Figure 10 As shown.

[0270] Example 6: In vitro orexin receptor antagonistic activity experiment

[0271] Experimental Principle: Orexin activates voltage-gated calcium channels, transient receptor potential channels, and intracellular calcium storage, inducing a rapid and sustained increase in intracellular calcium. After a compound antagonizes orexin receptors, the strength of the antagonistic effect is reflected in the change in intracellular calcium ion concentration before and after the addition of an agonist. Flow cytometry is used to reflect intracellular calcium ion concentration through real-time fluorescence intensity; therefore, changes in intracellular calcium ion concentration can be reflected by measuring changes in cell fluorescence intensity during compound treatment. A large increase in fluorescence intensity indicates a weak antagonistic effect on orexin receptors, while a small increase in fluorescence intensity indicates a strong antagonistic effect.

[0272] Experimental materials: MEM-Alpha medium, fetal bovine serum (FBS), penicillin-streptomycin solution (double antibody), PBS buffer, 0.5% trypsin, calcium ion detection kit (Fluo-4, catalog number S1061S).

[0273] Experimental method: Logarithmic growth phase Chinese hamster ovary cells (CHO cells) were collected at 1.5 × 10⁶ cells per well. 5Cells were seeded into 12-well plates and cultured at 37°C for 24 h. The culture medium was discarded, and the cells were washed twice with PBS buffer. 2 μL of the 10 mM test compound (Suv, (±)-Nef, (R,S)-Nef, (R,R)-Nef, (S,R)-Nef, or (S,S)-Nef) was added to each well. The cells were cultured in MEM-Alpha medium for 24 h. The culture medium was discarded, and the cells were washed twice with PBS. After digestion with 0.5% trypsin, the cells were resuspended in culture medium and washed once with PBS. Adherent cells were centrifuged at 1000 rpm for 5 min at room temperature, and the supernatant was discarded. 250 μL of Fluo-4 staining solution was added to each collected cell tube, and the cells were resuspended to form a single-cell suspension. The cells were incubated at 37°C in the dark for 30 min. After incubation, samples were loaded and detected using flow cytometry. After detection, the changes in fluorescence intensity before and after the addition of orexin-A or orexin-B (concentration 10pM-1μM) were measured to obtain the fluorescence intensity change curve over time.

[0274]

[0275] Experimental results: such as Figure 11 As shown, flow cytometry was used to detect changes in intracellular calcium ion concentration in CHO cells. After stimulation with orexin A or orexin B, the intracellular calcium ion concentration in CHO cells (C-2 blank control group) significantly increased. The positive control drugs Suv, (±)-Nef, (R,S)-Nef, (R,R)-Nef, (S,R)-Nef, and (S,S)-Nef all effectively inhibited the increase in intracellular calcium ion concentration induced by orexin A or orexin B. Their antagonistic activity against orexin receptors was comparable to that of Suv. The antagonistic activity varied depending on the chiral configuration of the compounds, with (R,S)-Nef and (R,R)-Nef exhibiting stronger antagonistic activity.

Claims

1. A methylnepenone derivative intermediate, characterized in that, It is a compound with the following structural formula, or its racemic form, enantiomer, or mixture thereof, or a pharmaceutically acceptable salt thereof: ； Among them, R1 is selected from chlorine, bromine, and iodine; R2 is selected from methyl, acetyl, benzoyl, and C(O)CF3.

2. The method for preparing the intermediate of methylnepenone derivative according to claim 1, characterized in that, When R1 is bromine and R2 is methyl, the preparation method of the methyl lotusine derivative intermediate includes the following steps: S1. Compound 1 was obtained by bromination of 4-hydroxyphenylacetic acid under alkaline conditions. S2, Compound 1 and 3,4-dimethoxyphenethylamine undergo a condensation reaction to give Compound 2; Alternatively, the carboxylic acid on compound 1 is activated to an acyl chloride, which then reacts with 3,4-dimethoxyphenethylamine under alkaline conditions to give compound 2; S3 and compound 2 undergo dehydration and ring closure to obtain compound 3; S4 and compound 3 were reduced to obtain compound 4; S5 and compound 4 react with a methylating agent to methylate the hydrogen atoms on nitrogen to obtain compound 5; S6 and compound 5 react with a phenolic hydroxyl protecting agent under alkaline conditions to obtain compound 6; The structure of compound 1 is as follows: ; The structure of compound 2 is as follows: ; The structure of compound 3 is as follows: ; The structure of compound 4 is as follows: ; The structure of compound 5 is as follows: .

3. The preparation method according to claim 2, characterized in that, The steps of the bromination reaction include: adding 30-40 parts of p-toluenesulfonic acid monohydrate to 20-25 parts of 4-hydroxyphenylacetic acid, followed by slowly adding 30-40 parts of the brominating reagent at -15 to -25°C, and reacting overnight; the brominating reagent includes bromine water or one of N-bromosuccinimide.

4. The preparation method according to claim 3, characterized in that, The brominating reagent is N-bromosuccinimide.

5. The preparation method according to claim 2, characterized in that, The condensation reaction step includes: adding 50-55 parts of condensing agent and 55-60 parts of 3,4-dimethoxyphenethylamine to 45-50 parts of compound 1, and reacting at room temperature for 2-3 hours; wherein the condensing agent is selected from 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimide, dicyclohexylcarbodiimide, 1-hydroxy-7-azabenzotriazole, 1-hydroxybenzotriazole or 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate.

6. The preparation method according to claim 5, characterized in that, The molar ratio of compound 1 to condensing agent is 1.5~3:1; the molar ratio of compound 1 to 3,4-dimethoxyphenylethylamine is 1~1.5:1; the reaction temperature is 0-30℃; and the reaction time is 2-5 hours.

7. The preparation method according to claim 2, characterized in that, The phenolic hydroxyl protecting agent is bromomethyl methyl ether; the reaction step of S6 includes: adding 2-3 parts of sodium hydride or 12-15 parts of N,N-diisopropylethylamine and 6-8 parts of the phenolic hydroxyl protecting agent to 15-25 parts of compound 5, reacting for 5-40 minutes, and then adding water to terminate the reaction.

8. The use of the methylnepenone derivative intermediate according to claim 1 in the preparation of compound 13, characterized in that, The structure of compound 13 is as follows: .

9. The application according to claim 8, characterized in that, Compound 13 was obtained by reacting the methyl lotusine derivative intermediate shown in Formula 6 and compound 12 under alkaline high-temperature conditions with a catalyst and ligand, followed by an Ullmann reaction. The structure of compound 12 is as follows: ； Wherein, R is selected from methyl, acetyl, benzoyl, and C(O)CF3; The catalyst is selected from a mixture of cuprous iodide or cuprous dimethyl sulfide bromide; the ligand is selected from one of 1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, N,N-dimethylglycine, N1,N2-bis([1,1'-biphenyl]-2-yl)glyoxamide, 2-pyridinecarboxylic acid, and 2-pyridinecarboxylic acid•pyridine salt; the molar ratio of compound 6 to compound 12 is 1:0.5~2, the molar ratio of compound 6 to catalyst is 1:0.1~2.0, the molar ratio of compound 6 to ligand is 1:0.1~2.0, the molar ratio of compound 6 to base is 1:1~5.0; the reaction temperature is 80℃-150℃, and the reaction time is 2-7 days.

10. The application according to claim 9, characterized in that, When R is methyl, the preparation method of compound 12 includes: (1) Using vanillin as a raw material, compound 7 was synthesized by Henry reaction with nitromethane under the action of a catalyst; (2) Compound 7 was reduced to synthesize compound 8 under the action of a reducing agent; (3) Compound 8 is synthesized by condensation reaction with 4-methoxyphenylacetic acid under the action of a condensing agent; or Compound 8 is activated to an acyl chloride and reacted with 4-methoxyphenylacetic acid under alkaline conditions to synthesize Compound 9. (4) Compound 9 was cyclically closed in an inert solvent by the action of a dehydrating agent to synthesize compound 10; (5) Compound 10 was reduced to synthesize compound 11 under the action of a reducing agent; (6) Compound 11 was reacted with a methylating agent to synthesize compound 12; The structural formula of compound 7 is: ; The structural formula of compound 8 is: ; The structural formula of compound 9 is: ; The structural formula of compound 10 is: ; The structural formula of compound 11 is: .

11. A methylnepenone derivative, characterized in that, It is a compound with the following structural formula, or its racemic, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof: 。 12. The application of the methyl lotusine derivative according to claim 11 in the preparation of methyl lotusine, characterized in that, The structure of the methylnephrine is as follows: 。

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