A synthesis process of a galnac compound

Abstract

The application discloses a synthesis process of GalNAc compounds, and belongs to the technical field of compound synthesis. The synthesis process can synthesize GalNAc-L96 and analogs thereof by controlling specific raw materials and parameters. The synthesis process is simple, and the yield and purity of the synthesized target product are high. Specifically, the purity can reach 99%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compound synthesis, in particular to a synthesis process of GalNAc compound. BACKGROUND

[0002] GalNAc (N-acetylgalactosamine) conjugation is one of the most commonly used small nucleic acid drug delivery systems. GalNAc is a targeting ligand of the sialic acid receptor ASGPR, and has high affinity and internalization capacity with liver surface cells. GalNAc is covalently conjugated to small nucleic acid drug molecules of different sequences to form a polysaccharide-small nucleic acid conjugate, which utilizes the binding capacity between GalNAc and ASGPR specifically expressed by liver cells to accurately deliver the drug to the liver, into the cell to form an endosome, thereby achieving specific delivery to liver cells and enabling the drug to enter the cell to function.

[0003] At present, the process for synthesizing the core compound molecule L96 and its analogues conjugated with GalNAc has the problems of complex synthesis process, low synthesis yield and purity. SUMMARY

[0004] The purpose of the present application is to provide a synthesis process of GalNAc compound, which can synthesize GalNAc-L96 and its analogues, and the synthesis process is simple, and the yield and purity of the target product are high.

[0005] In order to achieve the above-mentioned purpose of the present application, the following technical solutions are adopted:

[0006] The present application provides a synthesis process of GalNAc compound, and the structural formula of the GalNAc compound is , wherein k, I, m and n are positive integers.

[0007] The synthesis process comprises the following steps:

[0008] (1) Trimethylol nitromethane and tert-butyl acrylate are dissolved in a solvent, and then a base is added for stirring reaction and extraction. The organic phase is collected, an acid is added to the organic phase for further stirring reaction, and then the solvent is removed, separated and purified to obtain compound 1;

[0009] (2) Compound C is added dropwise to a solution of compound B and stirred to react, and then distilled under reduced pressure to obtain compound 2 in a viscous state, wherein the structural formula of compound B is , and the structural formula of compound C is ;

[0010] (3) Compound 1 and carbonyl diimidazole are added to tetrahydrofuran and stirred to activate, after the activation is completed, compound 2 is added dropwise, triethylamine is further added to continue stirring reaction, after the solvent is removed, saturated brine is added, then extraction is performed, the organic phase is concentrated, separated and purified to obtain compound 3;

[0011] (4) D-galactosamine pentacetate and compound 3 are dissolved in dichloromethane, then under low temperature and nitrogen protection, trimethylsilyl trifluoromethanesulfonate dichloromethane solution is added dropwise, after the dropwise addition is completed, the temperature is increased to room temperature to perform stirring reaction, after the reaction is completed, saturated sodium bicarbonate aqueous solution is added, then the organic phase is separated, concentrated, separated and purified to obtain compound 4;

[0012] (5) Under nitrogen protection, palladium-carbon is added to a methanol solution of compound 4, hydrogen is filled and stirring reaction is performed under pressurized conditions, after the reaction is completed, diatomite is filtered, washed and concentrated to obtain compound 5;

[0013] (6) (2S, 4R)-4-hydroxypyrrolidine-2-carboxylic acid is dissolved in tetrahydrofuran, then under nitrogen protection, borane dimethyl sulfide complex is added to perform reaction, then quenching, solvent removal and purification are performed to obtain compound 6;

[0014] (7) Compound 6 is dissolved in pyridine, DMAP is added and stirred to obtain a pyridine solution of compound 6, under nitrogen protection, 4, 4'-dimethoxytriphenylchloromethane pyridine solution is added dropwise to the pyridine solution of compound 6 to perform stirring reaction, after the reaction is completed, the solvent is removed, saturated sodium bicarbonate aqueous solution is added, then extraction is performed, the organic phase is collected, washed, dried, separated and purified to obtain compound 7;

[0015] (8) Compound D is mixed with dichlorosulfoxide, heated to distill and stirred, dichlorosulfoxide is removed to obtain a white solid, N-hydroxysuccinimide dichloromethane solution is added dropwise to the dichloromethane solution of the white solid to perform stirring reaction, then saturated sodium bicarbonate solution is added to the reaction product, the organic phase is separated, washed, dried and removed to obtain solid compound 8, wherein the structural formula of compound D is ;

[0016] (9) Compound 8, HBTU and N, N-diisopropylethylamine are added to DMF, then under stirring, compound 7 is further added to perform reaction, after the reaction is completed, the solvent is removed, saturated sodium bicarbonate solution is added, the organic phase is collected by extraction, washed, dried, separated and purified to obtain compound 9;

[0017] (10) adding compound 5, compound 9 and N,N-diisopropylethylamine into tetrahydrofuran for stirring reaction, after the reaction is completed, removing the organic solvent, adding saturated sodium bicarbonate solution, extracting and collecting the organic phase, washing, drying, separating and purifying to obtain compound 10;

[0018] adding compound 10, compound E and DMAP into acetonitrile for stirring reaction, after the reaction is completed, removing the organic solvent, adding saturated sodium bicarbonate solution, extracting and collecting the organic phase, adding base into the organic phase, removing the organic solvent, and separating and purifying to obtain the GalNAc compound, wherein the structural formula of compound E is .

[0019] Preferably, in the step (1), the molar ratio of trimethyl nitromethane and tert-butyl acrylate is 1:(4.5-5.5);

[0020] The solvent is a mixture of DMSO and distilled water in a volume ratio of (1.8-2.2):1;

[0021] The added concentration of the base is 0.15-0.2M;

[0022] The stirring reaction time is not less than 10h, and the reaction temperature is room temperature; the extractant used for extraction is ethyl acetate;

[0023] The continuous stirring reaction time is not less than 10h, and the temperature is room temperature.

[0024] Preferably, in the step (2), the molar ratio of compound C and compound B is 1:(0.8-1.2);

[0025] The stirring reaction temperature is room temperature, and the reaction time is not less than 10h.

[0026] Preferably, in the step (3), the molar ratio of compound 1 and carbonyl diimidazole is 1:(3-5);

[0027] The added amount of triethylamine is (1.8-2.2):1 of the molar ratio of compound 1;

[0028] The continuous stirring reaction time is not less than 10h;

[0029] The solvent used for extraction is DCM.

[0030] Preferably, in the step (4), the mass ratio of D-galactosamine pentacetate, compound 3 and trimethylsilyl trifluoromethanesulfonate is (120-130):(80-85):(75-80);

[0031] The stirring reaction time is not less than 10h.

[0032] Preferably, in the step (5), the pressurized pressure is 1-4 atmospheres, the stirring reaction time is 11-13 hours, and the reaction temperature is room temperature.

[0033] Preferably, in the step (6), the molar ratio of (2S, 4R)-4-hydroxypyrrolidine-2-carboxylic acid and borane dimethyl sulfide complex is 1: (2.5-3.5).

[0034] The reaction temperature is room temperature, and the reaction time is 8-12 hours.

[0035] Preferably, in the step (7), the molar ratio of compound 6 and 4,4'-dimethoxytrityl chloride is 1: (0.5-1.5).

[0036] The stirring reaction time is not less than 12 hours.

[0037] Preferably, in the step (8), the molar ratio of compound D and N-hydroxysuccinimide is 1: (1-1.5).

[0038] The stirring reaction time is 8-12 hours.

[0039] In the step (9), the molar ratio of compound 8, HBTU, N, N-diisopropylethylamine and compound 7 is (0.4-0.6): (0.5-0.6): (0.55-0.65): (0.4-0.6).

[0040] The reaction time is not less than 10 hours.

[0041] Preferably, in the step (10), the molar ratio of compound 5, compound 9 and N, N-diisopropylethylamine is (0.05-0.07): (0.6-0.7): (0.07-0.08); the stirring reaction time of compound 5, compound 9 and N, N-diisopropylethylamine added into tetrahydrofuran is 20-28 hours.

[0042] The molar ratio of compound 10, compound E and DMAP is (0.03-0.05): (0.07-0.09): (0.1-0.15); the stirring reaction time of compound 10, compound E and DMAP added into acetonitrile is 10-14 hours.

[0043] Compared with the prior art, the present application has at least the following beneficial effects:

[0044] The synthesis method of the present application can synthesize GalNAc-L96 and its analogues, and has the advantages of simple process, high yield and high purity of the target product, and the purity is as high as 99%. DETAILED DESCRIPTION

[0045] The technical solutions of the present application will be described in detail below with reference to the embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.

[0046] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present application should be understood as the general meanings understood by the skilled in the art to which the present application belongs.

[0047] The present application provides a synthesis process of a GalNAc compound, and the structural formula of the GalNAc compound is , wherein k, I, m, and n are positive integers.

[0048] The synthesis process comprises the following steps:

[0049] (1) Trimethyl ortho-nitromethane and tert-butyl acrylate are dissolved in a solvent, and then a base is added for stirring reaction and extraction. The organic phase is collected, an acid is added to the organic phase for further stirring reaction, the solvent is removed, and then separation and purification are performed to obtain compound 1.

[0050] (2) Compound C is added dropwise to a solution of compound B and stirring reaction is performed, and then reduced pressure distillation is performed to obtain compound 2 in a viscous state, wherein the structural formula of compound B is , and the structural formula of compound C is .

[0051] (3) Compound 1 and carbonyl diimidazole are added to tetrahydrofuran and stirring activation is performed, then compound 2 is added dropwise after the activation is completed, triethylamine is further added for stirring reaction, the solvent is removed, saturated brine is then added, and then extraction is performed. The organic phase is concentrated, separated and purified to obtain compound 3.

[0052] (4) D-galactosamine pentacetate and compound 3 are dissolved in dichloromethane, then under low temperature and nitrogen protection, trimethylsilyl trifluoromethanesulfonate in dichloromethane solution is added dropwise, after the dropwise addition is completed, stirring reaction is performed at room temperature, after the reaction is completed, saturated sodium bicarbonate aqueous solution is added, and then the organic phase is separated, concentrated and purified to obtain compound 4.

[0053] (5) Under nitrogen protection, palladium-carbon is added to a methanol solution of compound 4, hydrogen is then filled and stirring reaction is performed under pressure, after the reaction is completed, diatomite is used for filtration, washing and concentration to obtain compound 5.

[0054] (6) (2S, 4R)-4-hydroxypyrrolidine-2-carboxylic acid is dissolved in tetrahydrofuran, then under nitrogen protection, borane dimethyl sulfide complex is added for reaction, and then quenching, removal of the solvent and purification are performed to obtain compound 6.

[0055] (7) Compound 6 is dissolved in pyridine, DMAP is added and stirred to obtain a pyridine solution of compound 6, a pyridine solution of 4,4'-dimethoxytrityl chloride is added dropwise into the pyridine solution of compound 6 under nitrogen protection, and the reaction is stirred until the reaction is completed, the solvent is removed, saturated sodium bicarbonate aqueous solution is added, and then extraction is performed, the organic phase is collected, washed, dried, separated and purified to obtain compound 7;

[0056] (8) Compound D is mixed with dichlorosulfoxide, heated and distilled, and stirred to remove dichlorosulfoxide to obtain a white solid; a dichloromethane solution of N-hydroxysuccinimide is added dropwise into a dichloromethane solution of the white solid, and the reaction is stirred, then saturated sodium bicarbonate solution is added to the reaction product, the organic phase is separated, washed, dried, and the organic solvent is removed to obtain solid compound 8, wherein the structural formula of compound D is ;

[0057] (9) Compound 8, HBTU and N,N-diisopropylethylamine are added to DMF, then compound 7 is added under stirring, and the reaction is performed, after the reaction is completed, the solvent is removed, saturated sodium bicarbonate solution is added, the organic phase is collected by extraction, washed, dried, separated and purified to obtain compound 9;

[0058] (10) Compound 5, compound 9 and N,N-diisopropylethylamine are added to tetrahydrofuran for stirring reaction, after the reaction is completed, the organic solvent is removed, saturated sodium bicarbonate solution is added, the organic phase is collected by extraction, washed, dried, separated and purified to obtain compound 10;

[0059] Compound 10, compound E and DMAP are added to acetonitrile for stirring reaction, after the reaction is completed, the organic solvent is removed, saturated sodium bicarbonate solution is added, the organic phase is collected by extraction, a base is added to the organic phase, the organic solvent is removed, and then separated and purified to obtain the GalNAc compound, wherein the structural formula of compound E is .

[0060] In the present application, the separation and purification method is not strictly limited, and the conventional separation and purification method in the art can be used, preferably, in an embodiment, the separation and purification can be performed by column chromatography, and the elution solvent is dichloromethane / ethanol.

[0061] In some embodiments, in step (1), the molar ratio of trimethylol nitromethane and tert-butyl acrylate is 1: (4.5-5.5);

[0062] The solvent is a mixture of DMSO and distilled water in a volume ratio of (1.8-2.2):1;

[0063] The concentration of the added base is 0.15-0.2 M.

[0064] The stirring reaction time is not less than 10 hours, and the reaction temperature is room temperature; the extraction agent used for extraction is ethyl acetate;

[0065] The stirring reaction time is not less than 10 hours, and the reaction temperature is room temperature.

[0066] In some embodiments, in the step (2), the molar ratio of the compound C to the compound B is 1:(0.8-1.2);

[0067] The stirring reaction temperature is room temperature, and the reaction time is not less than 10 hours.

[0068] Preferably, in the step (3), the molar ratio of the compound 1 to carbonyldiimidazole is 1:(3-5);

[0069] The added amount of triethylamine is (1.8-2.2):1 in molar ratio to the compound 1;

[0070] The stirring reaction time is not less than 10 hours;

[0071] The solvent used for extraction is DCM.

[0072] Preferably, in the step (4), the mass ratio of D-galactosamine pentacetate, the compound 3 and trimethylsilyl trifluoromethanesulfonate is (120-130):(80-85):(75-80);

[0073] The stirring reaction time is not less than 10 hours.

[0074] In some embodiments, in the step (5), the pressure is 1-4 atmospheres, the stirring reaction time is 11-13 hours, and the reaction temperature is room temperature.

[0075] Preferably, in the step (6), the molar ratio of (2S,4R)-4-hydroxypyrrolidine-2-carboxylic acid to borane dimethyl sulfide complex is 1:(2.5-3.5);

[0076] The reaction temperature is room temperature, and the reaction time is 8-12 hours.

[0077] In some embodiments, in the step (7), the molar ratio of the compound 6 to 4,4'-dimethoxytritylchloromethane is 1:(0.5-1.5);

[0078] The stirring reaction time is not less than 12 hours.

[0079] Preferably, in the step (8), the molar ratio of the compound D to N-hydroxysuccinimide is 1:(1-1.5);

[0080] The stirring reaction time is 8-12 hours.

[0081] In the step (9), the molar ratio of compound 8, HBTU, N,N-diisopropylethylamine and compound 7 is (0.4-0.6):(0.5-0.6):(0.55-0.65):(0.4-0.6);

[0082] The reaction time is not less than 10 h.

[0083] In some embodiments, in the step (10), the molar ratio of compound 5, compound 9 and N,N-diisopropylethylamine is (0.05-0.07):(0.6-0.7):(0.07-0.08); the stirring reaction time of compound 5, compound 9 and N,N-diisopropylethylamine added into tetrahydrofuran is 20-28 h;

[0084] The molar ratio of compound 10, compound E and DMAP is (0.03-0.05):(0.07-0.09):(0.1-0.15); the stirring reaction time of compound 10, compound E and DMAP added into acetonitrile is 10-14 h.

[0085] The technical solutions of the present application are further described in detail through specific examples.

[0086] Example 1

[0087] This example is a synthesis method of a GalNAc-L96 compound, and the structural formula of GalNAc-L96 is ;

[0088] The synthesis method comprises:

[0089] (1) 151.12 g of trimethylol nitromethane (1.0 mol, 1.0 eq.) and 640.85 g of tert-butyl acrylate (5.0 mol, 5.0 eq.) are added to a mixed solvent of 2 liters of DMSO and 1 liter of distilled water, 280.55 g of potassium hydroxide (0.5 mol, 0.5 eq.) is added in batches at room temperature, and stirring is continued for 10 hours, 1 liter of distilled water is added, 1 liter of ethyl acetate is extracted 3 times, the combined organic phase is washed with water 5 times, 200 mL of formic acid is added to the organic phase, and stirring is carried out at room temperature for 10 hours. After the organic solvent is distilled under reduced pressure, a crude product is obtained, which is separated and purified by column chromatography, and the elution solvent is dichloromethane / methanol, and compound 1 (169.21 g, yield 46.1%) is separated;

[0090] The reaction formula is ;

[0091] (2) 200.24 g of δ-valerolactone (2.0 mol, 1.0 eq.) was dissolved in 1 L of dry dichloromethane, 167 mL of 1,3-propanediamine (148.26 g, 2.0 mol, 1.0 eq.) was added dropwise at room temperature, and stirring was continued at room temperature for 10 hours after the dropwise addition was completed. Distillation under reduced pressure gave a viscous compound 2 (348.50 g, yield >99%);

[0092] The reaction formula is ;

[0093] (3) 146.84 g of compound 1 (0.4 mol, 1.0 eq.), 259.44 g of carbonyldiimidazole (1.6 mol, 4.0 eq.) were sequentially added to 1 L of dry tetrahydrofuran, and stirring was activated at room temperature. 209.10 g of compound 2 was dissolved in 1 L of dry tetrahydrofuran, and the dropwise addition time was controlled to 0.5 hours. After the dropwise addition was completed, 280 mL of triethylamine (202.38 g, 2.0 mol, 5.0 eq.) was added, and stirring was continued at room temperature for 10 hours. The solvent was removed by distillation, 500 mL of saturated brine was added, and the crude product was extracted with an organic solvent DCM (500 mL, 4 times). The organic phase was combined and concentrated, and then purified by column chromatography. The elution solvent was dichloromethane / methanol, and compound 3 (267.90 g, yield 80.1%) was separated;

[0094] The reaction formula is ;

[0095] (4) 124.60 g of D-galactosamine pentaacetate (0.32 mol, 3.2 eq.), 83.60 g of compound 3 (0.1 mol, 1.0 eq.) was dissolved in 300 mL of dry dichloromethane, and 77.79 g of trimethylsilyl trifluoromethanesulfonate was dissolved in 200 mL of dry dichloromethane. Slowly dropwise addition was performed under nitrogen protection, and the temperature of the mixed solution was controlled to 0~5 ℃. After the dropwise addition was completed, the temperature was slowly increased to room temperature, and stirring was continued for 10 hours. 500 mL of saturated sodium bicarbonate aqueous solution was added, the organic phase was separated, the aqueous solution was extracted with 500 mL of dichloromethane twice, and the combined organic phase was washed with 500 mL of saturated brine. The organic phase was concentrated to give a crude compound S4, which was purified by column chromatography. The elution solvent was dichloromethane / methanol, and compound 4 was separated;

[0096] The reaction formula is ;

[0097] (5) Compound 4 was dissolved in 1 liter of methanol, 20 grams of palladium-carbon (10%) was added under nitrogen protection, hydrogen was flushed in, the pressure was controlled at 1-4 atmospheres, and stirring was carried out at room temperature for 12 hours. After the reaction system was filtered and washed with diatomite, the solution was concentrated to obtain Compound 5 (138.1 grams, the yield of the two-step reaction of (4) and (5) was 77.1%);

[0098] The reaction formula is ;

[0099] (6) 131.13 grams of (2S, 4R)-4-hydroxypyrrolidine-2-carboxylic acid (1.0 mol, 1.0 eq.) was dissolved in 1 liter of tetrahydrofuran, 1.5 liters of borane dimethyl sulfide complex (2.0 mol / L) (3.0 mol, 3.0 eq.) was slowly added under nitrogen protection and temperature control at 5-10°C, and then slowly increased to room temperature. The reaction was continued for 10 hours under nitrogen protection, methanol was added under nitrogen protection to quench the reaction, the solvent was removed by distillation under reduced pressure, and Compound 6 was obtained after the crude product was extracted with anhydrous isopropyl alcohol and the isopropyl alcohol was distilled off under reduced pressure;

[0100] The reaction formula is ;

[0101] (7) Compound 6 obtained in step (6) was dissolved in 500 milliliters of dry pyridine, 2 grams of DMAP was added, and stirring was carried out at room temperature for 0.5 hours to obtain a pyridine solution of Compound 6; 304.95 grams of 4,4'-dimethoxytrityl chloride (DMT-Cl, 0.9 mol, 0.9 eq.) was dissolved in 1 liter of dry pyridine, and was slowly added dropwise to the pyridine solution of Compound 6 under nitrogen protection. After the dropwise addition was completed, stirring was continued at room temperature for 12 hours. After the pyridine was removed by distillation under reduced pressure, 1 liter of saturated aqueous sodium bicarbonate solution was added, 1 liter of dichloromethane was extracted three times, the organic phases were combined, washed with saturated brine, dried with sodium sulfate, concentrated, separated and purified by column chromatography, and eluted with dichloromethane / methanol to obtain 280.22 grams of Compound 7 (the yield of the two-step reaction of steps (6) and (7) was 66.8%);

[0102] The reaction formula is ;

[0103] (8) 230.30 g of dodecanedioic acid (1.0 mol, 1.0 eq.) was mixed with 1 L of dichlorosulfoxide, heated and refluxed, stirred for more than 4 hours, dichlorosulfoxide was removed by distillation under reduced pressure, and a white solid was obtained; the white solid was dissolved in 1 L of dry dichloromethane, 1 L of N-hydroxysuccinimide dichloromethane solution (115.08 g, 1.0 mol, 1.0 eq.) was slowly added dropwise under temperature control, after the dropwise addition was completed, stirring was continued at room temperature for 10 hours, saturated sodium bicarbonate was added, the pH value was adjusted to 6, the organic phase was separated, the aqueous phase was extracted twice with dichloromethane, the combined organic phase was washed with saturated brine, dried over sodium sulfate, and the organic solvent was removed by concentration to obtain a solid compound 8 (420.13 g, yield 72.0%);

[0104] The reaction formula is ;

[0105] (9) 163.69 g of compound 8 (0.5 mol, 1.0 eq.), 208.59 g of HBTU (0.55 mol, 1.1 eq.) and 80 g of N,N-diisopropyl ethylamine (0.6 mol, 1.2 eq.) were sequentially added to 1 L of dry DMF, 209.76 g of compound 7 (0.5 mol, 1.0 eq.) was added under stirring at room temperature, stirring was continued at room temperature for 10 hours, the solvent was removed by distillation under reduced pressure, 1 L of saturated sodium bicarbonate aqueous solution was added, 1 L of dichloromethane was extracted three times, the combined organic phase was washed with saturated brine, dried over sodium sulfate, concentrated, purified by column chromatography, and eluted with dichloromethane / methanol, and 268.31 g of compound 9 was separated (reaction yield 73.6%);

[0106] The reaction formula is

[0107] ;

[0108] (10) 107.63 g of compound 5 (0.06 mol, 1.0 eq.), 48.11 g of compound 9 (0.066 mol, 1.1 eq.) and 9.31 g of N,N-diisopropyl ethylamine (0.072 mol, 1.2 eq.) were sequentially added to 500 mL of tetrahydrofuran, stirred at room temperature for 24 hours, the organic solvent was removed by distillation under reduced pressure, 1 L of saturated sodium bicarbonate aqueous solution was added, 1 L of dichloromethane was extracted three times, the combined organic phase was washed with saturated brine, dried over sodium sulfate, concentrated, purified by column chromatography, and 102.69 g of compound 10 was separated (reaction yield 71.1%, HPLC purity 99%);

[0109] The reaction formula is:

[0110] ;

[0111] 96.31 g of compound 10 (0.04 mol, 1.0 eq.), 8.0 g of succinic anhydride (0.08 mol, 2.0 eq.), 14.6 g of DMAP (0.12 mol, 3.0 eq.) were added into 500 mL of acetonitrile in turn, stirred at room temperature for 12 hours, removed the organic solvent by distillation under reduced pressure, added 1 L of saturated sodium bicarbonate aqueous solution, extracted with 1 L of dichloromethane for 3 times, combined the organic phase, added base to the organic phase, removed the organic solvent by distillation under reduced pressure, separated and purified by column chromatography, and 80.2 g of compound GalNAc-L96 was separated (the yield of the reaction was 80%, and the HPLC purity was 99%);

[0112] The reaction formula is:

[0113] .

[0114] In summary, the synthesis method of the present application can synthesize GalNAc-L96, and the yield and purity of the target product are high, and the purity is as high as 99%.

[0115] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application.

Claims

1. A process for the synthesis of a GalNAc-based compound, characterized in that, The structural formula of the GalNAc compound is wherein k, I, m, and n are positive integers. The synthesis process comprises the following steps: (1) trimethylol nitromethane and tert-butyl acrylate are dissolved in a solvent, a base is added to stir and react, extraction is performed, an organic phase is collected, an acid is added to the organic phase to continue stirring and reacting, a solvent is removed, and compound 1 is obtained by separation and purification, wherein the structural formula of compound 1 is ; (2) Compound C is added dropwise to a solution of Compound B and stirred to react, and distilled under reduced pressure to obtain viscous Compound 2, wherein Compound B has a structural formula of , Compound C has a structural formula of , and Compound 2 has a structural formula of ; (3) Compound 1 and carbonyl diimidazole are added to tetrahydrofuran and stirred to activate, after the activation is completed, Compound 2 is added dropwise, triethylamine is added to continue stirring the reaction, after the solvent is removed, saturated brine is added, then extraction is performed, the organic phase is concentrated, separated and purified to obtain Compound 3, wherein the structural formula of Compound 3 is ; (4) dissolving D-galactosamine pentaacetate and compound 3 in dichloromethane, then adding dropwise a dichloromethane solution of trimethylsilyl trifluoromethanesulfonate at low temperature under nitrogen protection, after the dropwise addition is completed, the reaction is stirred at room temperature, after the reaction is completed, saturated sodium bicarbonate aqueous solution is added, then the organic phase is separated, concentrated, separated and purified to obtain compound 4, wherein the structural formula of compound 4 is ; (5) under the protection of nitrogen, adding palladium-carbon to the methanol solution of compound 4, then filling hydrogen and stirring under the condition of pressure, after the reaction is completed, filtering, washing and concentrating through diatomite to obtain compound 5, wherein the structural formula of compound 5 is ; (6) dissolving (2S, 4R)-4-hydroxypyrrolidine-2-carboxylic acid in tetrahydrofuran, then, under the protection of nitrogen, adding borane dimethyl sulfide complex to react, and then quenching, removing solvent and purifying to obtain compound 6, wherein the structural formula of compound 6 is ; (7) Compound 6 is dissolved in pyridine, DMAP is added and stirred to obtain a pyridine solution of compound 6, a pyridine solution of 4,4'-dimethoxytrityl chloride is added dropwise to the pyridine solution of compound 6 under nitrogen protection, and the reaction is stirred until the reaction is completed. The solvent is removed, saturated aqueous sodium bicarbonate solution is added, and then extracted. The organic phase is collected, washed, dried, separated and purified to obtain compound 7, wherein the structural formula of compound 7 is ; (8) mixing, heating, and distilling compound D with thionyl chloride, stirring, and removing the thionyl chloride to obtain a white solid; adding a dichloromethane solution of N-hydroxysuccinimide dropwise to a dichloromethane solution of the white solid to perform a stirring reaction, further adding a saturated sodium bicarbonate solution to the reaction product, separating an organic phase, washing, drying, and removing an organic solvent to obtain a solid compound 8, wherein a structural formula of the compound D is , and a structural formula of the compound 8 is ; (9) adding compound 8, HBTU and N,N-diisopropylethylamine to DMF, then, under stirring, adding compound 7 to react, after the reaction is completed, removing the solvent, adding saturated sodium bicarbonate solution, extracting and collecting the organic phase, washing, drying, separating and purifying to obtain compound 9, wherein the structural formula of compound 9 is ; (10) adding compound 5, compound 9 and N,N-diisopropylethylamine into tetrahydrofuran for stirring reaction, after the reaction is completed, removing the organic solvent, adding saturated sodium bicarbonate solution, collecting the organic phase by extraction, washing, drying, separating and purifying to obtain compound 10, wherein the structural formula of compound 10 is ； The compound 10, the compound E and DMAP are added into acetonitrile for stirring reaction, after the reaction is completed, the organic solvent is removed, a saturated sodium bicarbonate solution is added, the organic phase is collected by extraction, a base is added into the organic phase, the organic solvent is removed, and the GalNAc compound is obtained by separation and purification, wherein the compound E has a structural formula of .

2. The synthesis process of claim 1, wherein, In the step (1), the molar ratio of trimethyl nitromethane and tert-butyl acrylate is 1: (4.5-5.5); The solvent is a mixed solution of DMSO and distilled water in a volume ratio of (1.8-2.2):1; The adding concentration of the base is 0.15-0.2M; The stirring reaction time is not less than 10h, and the reaction temperature is room temperature; the extractant used for extraction is ethyl acetate; The continuous stirring reaction time is not less than 10h, and the temperature is room temperature.

3. The synthesis process of claim 1, wherein, In the step (2), the molar ratio of compound C and compound B is 1: (0.8-1.2); The stirring reaction temperature is room temperature, and the reaction time is not less than 10h.

4. The synthesis process of claim 1, wherein, In the step (3), the molar ratio of compound 1 and carbonyl diimidazole is 1: (3-5); The molar ratio of the adding amount of triethylamine and compound 1 is (1.8-2.2):1; The continuous stirring reaction time is not less than 10h; The solvent used for extraction is DCM.

5. The synthesis process of claim 1, wherein, In the step (4), the mass ratio of D-galactosamine pentaacetate, compound 3 and trimethylsilyl trifluoromethanesulfonate is (120-130):(80-85):(75-80); The stirring reaction time is not less than 10h.

6. The synthesis process of claim 1, wherein, In the step (5), the pressure is 1-4 atmospheres, the stirring reaction time is 11-13h, and the reaction temperature is room temperature.

7. The synthesis process of claim 1, wherein, In the step (6), the molar ratio of (2S,4R)-4-hydroxypyrrolidine-2-carboxylic acid and borane dimethyl sulfide complex is 1: (2.5-3.5); The reaction temperature is room temperature, and the reaction time is 8-12h.

8. The synthesis process of claim 1, wherein, In the step (7), the molar ratio of compound 6 and 4,4'-dimethoxytrityl chloride is 1: (0.5-1.5); The stirring reaction time is not less than 12h.

9. The synthesis process of claim 1, wherein, In the step (8), the molar ratio of compound D and N-hydroxysuccinimide is 1: (1-1.5); The stirring reaction time is 8-12h; In the step (9), the molar ratio of compound 8, HBTU, N,N-diisopropylethylamine and compound 7 is (0.4-0.6):(0.5-0.6):(0.55-0.65):(0.4-0.6); The reaction time is not less than 10h.

10. The synthesis process of claim 1, wherein, In the step (10), the molar ratio of compound 5, compound 9 and N,N-diisopropylethylamine is (0.05-0.07):(0.6-0.7):(0.07-0.08); the stirring reaction time of compound 5, compound 9 and N,N-diisopropylethylamine added into tetrahydrofuran is 20-28h; The molar ratio of compound 10, compound E and DMAP is (0.03-0.05):(0.07-0.09):(0.1-0.15); the time for stirring reaction of adding compound 10, compound E and DMAP into acetonitrile is 10-14 h. The molar ratio of compound 10, compound E and DMAP is (0.03-0.05):(0.07-0.09):(0.1-0.15); the time for stirring reaction of adding compound 10, compound E and DMAP into acetonitrile is 10-14 h.

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