Preparation method of galisvir intermediate

Abstract

The present invention belongs to the technical field of preparation of bulk drug intermediates and discloses a method for preparing a galisvir intermediate. The preparation method comprises the following steps: 1) hydrolyzing compound 7 under acidic conditions to produce compound 8; 2) sequentially reacting compound 8 with Boc anhydride and acetic anhydride to produce compound 9; and 3) reacting compound 9 with a chlorinating agent to produce the galisvir intermediate compound 10. This method can produce a high-purity galisvir intermediate suitable for industrial production of galisvir, achieving economic benefits. #imgabs0#

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of bulk drug intermediates, and in particular relates to a method for preparing a galixigide intermediate. Background Art

[0002] Galidesivir (Cas No. 249503-25-1, also known as Galidesivir, BCX4430 or Immucillin-A) is an adenosine analog and a direct-acting antiviral drug that can directly destroy viral RNA-dependent RNA polymerase (RdRp) and thus exhibit antiviral activity. Its structure is as follows:

[0003]

[0004] The journal article ("Study on the Inhibitory Effect of Galidesivir on Rabies Virus in Vitro", Xie Yuan et al., "Chinese Journal of Zoonoses", Issue 12, 2023) studied the in vitro inhibitory effect of Galidesivir (BCX4430) on rabies viruses of different virulences. Favipiravir (T-705) and ribavirin were used as positive controls, and direct immunofluorescence (DFA), real-time fluorescence quantitative PCR and half tissue culture infectious dose (TCID50) were used to analyze the in vitro inhibitory effect of BCX4430 on rabies virus. The results showed that after CVS-11 and SC16 infected N2a cells and BHK-21 cells, 250 μmol / L BCX4430 showed a good viral inhibitory effect, which was equivalent to the inhibitory effect of ribavirin at the corresponding concentration. Compared with the corresponding concentration of T-705 positive control, 250 μmol / L After BCX4430 treatment, viral titers (F=273.48, P<0.01) and mRNA copy numbers were significantly reduced (F=268.39, P<0.01). In vitro, BCX4430 can significantly inhibit rabies virus replication. Patent (CN116421608A) also discloses the use of galidesivir in inhibiting / eliminating rabies virus in vitro. Galidesivir was found to be highly effective in inhibiting RABV proliferation in cells with minimal cytotoxicity. It can be used as a rabies wound treatment drug to maximize virus elimination at the wound site, providing new insights into the treatment of rabies virus.

[0005] As a direct-acting antiviral molecule, galisvir is primarily used to treat infections caused by highly pathogenic viruses. Galisvir has in vitro activity against a variety of RNA viral pathogens, including filoviruses and emerging infectious agents. It has activity against more than 20 RNA viruses from nine families, including filoviruses, togaviruses, bunyaviruses, arenaviruses, paramyxoviruses, coronaviruses, and flaviviruses, and can be used for broad-spectrum antiviral applications.

[0006] The preparation method of galisvir has been reported in the prior art, for example, WO9919338A1 discloses:

[0007]

[0008] WO2006002231 discloses:

[0009]

[0010] The compound shown in Formula I is a key intermediate in the preparation of galisvir, which is crucial for the preparation of galisvir:

[0011]

[0012] However, in the prior art, the preparation methods of the compound represented by Formula I often suffer from low reaction efficiency, poor purity and yield. In particular, since by-products are easily generated during the reaction process, it is difficult to prepare a high-purity compound represented by Formula I, which is not conducive to the industrial production of galisvir.

[0013] Therefore, it is necessary to provide a method for preparing a galisvir intermediate to improve the preparation efficiency of the galisvir intermediate, to adapt to the industrial production of galisvir, and to meet economic benefits. Summary of the Invention

[0014] The present invention addresses the problems existing in the prior art and provides a method for preparing a galisvir intermediate. The method can obtain a high-purity galisvir intermediate with a high yield, thereby adapting to the industrial production of galisvir and meeting economic benefits.

[0015] In order to achieve the above object, the present invention provides a method for preparing a galisvir intermediate, wherein the galisvir intermediate is shown as compound 10:

[0016] The preparation method comprises the following steps:

[0017] 1) Compound 7 is hydrolyzed under acidic conditions to obtain compound 8;

[0018] 2) Compound 8 is reacted with Boc anhydride and acetic anhydride in sequence to obtain compound 9;

[0019] 3) Compound 9 reacts with a chlorinating agent to obtain the galisvir intermediate compound 10;

[0020]

[0021] In a preferred embodiment, alcohol is used as a solvent in step 1), and the mass volume ratio of compound 7 to alcohol is (0.5-5) g / 10 mL; the alcohol is selected from methanol, ethanol, propanol or n-butanol; concentrated acid is used to provide acidity in step 1), the concentrated acid concentration is 10-15 M, and the volume mass ratio of the concentrated acid to compound 7 is (10-30) mL:1 g; the concentrated acid is selected from concentrated hydrochloric acid and / or concentrated sulfuric acid.

[0022] In a preferred embodiment, the hydrolysis reaction conditions are: 70-90° C. for 8-15 h.

[0023] In a preferred embodiment, in step 2), compound 8 is reacted with Boc anhydride to obtain rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate, and rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate is reacted with acetic anhydride to obtain compound 9.

[0024] In a preferred embodiment, in step 2), the molar ratio of compound 8 to Boc anhydride is 1:1-5; the molar ratio of compound 8 to acetic anhydride is 1:2-6.

[0025] In a preferred embodiment, in step 2), solvent 1 and catalyst 1 are used when reacting compound 8 with Boc anhydride, the mass volume ratio of compound 8 to solvent 1 is 1 g:(50-100) mL, and the mass ratio of compound 8 to catalyst 1 is 1:0.5-3; the solvent 1 is selected from at least one of methanol, ethanol, propanol, n-butanol and water; and the catalyst 1 is triethylamine.

[0026] In a preferred embodiment, in step 2), the reaction conditions of compound 8 and Boc anhydride are: reaction at room temperature for 20-60 min.

[0027] In a preferred embodiment, in step 2), solvent 2 and catalyst 2 are used when reacting rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate with acetic anhydride, and the volume mass ratio of solvent 2 to compound 8 is (1-5) mL:1 g; the molar ratio of compound 8 to catalyst 2 is 1:0.005-0.05; the solvent 2 is pyridine, and the catalyst 2 is DMAP.

[0028] In a preferred embodiment, in step 2), the reaction conditions of rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate and acetic anhydride are: reaction at room temperature for 8-15 hours.

[0029] In a preferred embodiment, in step 3), the chlorinating agent is selected from benzyl(triethyl)ammonium chloride; the molar ratio of compound 9 to the chlorinating agent is 1:1-4; and the reaction conditions are 70-90° C. for 5-30 min.

[0030] In a preferred embodiment, in step 3), solvent 3 and catalyst 3 are used when compound 9 reacts with a chlorinating agent, the mass volume ratio of compound 9 to solvent 3 is 1 g: (30-100) mL, and the molar ratio of compound 9 to catalyst 3 is 1:5-10; the solvent 3 is acetonitrile; the catalyst 3 is N,N-dimethylaniline and / or phosphorus oxychloride; more preferably, a mixture of N,N-dimethylaniline and phosphorus oxychloride, the molar ratio of the two is 1:3-5.

[0031] In a preferred embodiment, the preparation process of compound 7 is as follows:

[0032]

[0033]

[0034] In a preferred embodiment, in step S1, anhydrous methyl tert-butyl ether and anisole are used as solvents in a volume ratio of 2-4:1, and a n-butyl lithium tetrahydrofuran solution with a molar concentration of 1-4 M is used as a catalyst; the mass volume ratio of compound 3 to the solvent is 1 g:(15-30) mL, and the mass volume ratio of compound 3 to the catalyst is 1 g:(1.5-2) mL; the molar ratio of compound 3 to compound R02 is 1:1-2; and the reaction conditions are -78°C for 1-3 h.

[0035] In a preferred embodiment, in step S2, ethanol is used as the solvent and sodium borohydride is used as the catalyst; the mass volume ratio of compound 4 to the solvent is 1 g:(5-15) mL, and the molar ratio of compound 4 to the catalyst is 1:0.8-1.5; and the reaction conditions are room temperature for 30-120 min.

[0036] In a preferred embodiment, in step S3, dimethyl sulfoxide is used as the solvent and 2-iodoacylbenzoic acid is used as the catalyst; the mass volume ratio of compound 5 to the solvent is 1 g:(5-15) mL, and the molar ratio of compound 5 to the catalyst is 1:4-8; and the reaction conditions are 35-40° C. and the reaction is carried out for 8-15 hours.

[0037] In a preferred embodiment, in step S4, 4AMS, ammonium formate and sodium cyanoborohydride are used as catalysts in a mass ratio of 1-2:1-2:1; the mass volume ratio of compound 6 to solvent is 1 g:(5-15) mL, and the mass ratio of compound 6 to catalyst is 1:2-4; and the reaction conditions are room temperature for 20-40 min.

[0038] In a preferred embodiment, the preparation process of compound 3 is as follows:

[0039]

[0040] In a preferred embodiment, in step A, tetrahydrofuran is used as the solvent and sodium hydride is used as the catalyst; the mass volume ratio of compound 1 to the solvent is 1 g:(10-20) mL, the molar ratio of compound 1 to the catalyst is 1:1-3; the molar ratio of compound 1 to compound R01 is 1:1-2; and the reaction conditions are -10-10°C for 1-4 hours.

[0041] In a preferred embodiment, in step B, methanol is used as the solvent and sodium methoxide is used as the catalyst; the mass volume ratio of compound 2 to the solvent is 1 g:(5-20) mL, and the molar ratio of compound 2 to the catalyst is 1:1-2; the reaction conditions are room temperature for 2-6 h.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The preparation method of the galisvir intermediate provided by the present invention can obtain a high-purity galisvir intermediate, so as to adapt to the industrial production of galisvir and meet economic benefits. DETAILED DESCRIPTION

[0044] It is worth noting that the raw materials used in the present invention are all common commercially available products, and their sources are not specifically limited.

[0045] The synthetic route of the intermediate of Calixvir is as follows:

[0046]

[0047] Example 1 Step 1: Synthesis of Compound 2

[0048] To a solution of 7-bromo-4-chloro-5H-pyrrolo[3,2-d]pyrimidine (50 g, 0.21 mol) in tetrahydrofuran (800 mL) were added sodium hydride (12.0 g, 0.30 mol, 60% mineral oil) and chloromethoxytoluene (43.8 g, 0.28 mol) at 0°C. The reaction mixture was stirred at 0°C for 2 h. The reaction was quenched with pure water (500 mL), and the aqueous phase was extracted with ethyl acetate (500 mL × 3). The combined organic phases were washed with brine (500 mL), dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo to afford 5-(benzyloxymethyl)-7-bromo-4-chloro-pyrrolo[3,2-d]pyrimidine (75 g, 90% purity, 89% yield) as a light yellow solid. This was used directly in the next reaction. MS (ESI) M / Z: 351.9 / 353.9 [M+H] + .

[0049] Example 2 Step 2: Synthesis of Compound 3

[0050] To a solution of 5-(benzyloxymethyl)-7-bromo-4-chloro-pyrrolo[3,2-d]pyrimidine (75 g, 0.21 mol) in methanol (800 mL) was added solid sodium methoxide (46.0 g, 0.25 mol) in portions. The reaction mixture was stirred at 25°C for 4 h. The reaction mixture was cooled to 0°C, quenched with pure water (800 mL), and the aqueous phase was extracted with ethyl acetate (800 mL x 3). The combined organic phases were washed with brine (800 mL), dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo. The crude product was purified by slurrying with a mixture of petroleum ether and methyl tert-butyl ether (10:1, 800 mL) to afford 5-(benzyloxymethyl)-7-bromo-4-methoxy-pyrrolo[3,2-d]pyrimidine (43 g, 91.6% purity, 53.13% yield) as a pale yellow solid.

[0051] MS (ESI) M / Z: 347.9 / 349.9 [M+H] + .

[0052] 1 H NMR:ET86557-11-P1A;

[0053] 1 H NMR (DMSO-d6, 400MHz) δ8.51(s,1H),8.13(s,1H),7.36-7.17(m,5H),5.74(s,2H),4.52(s,2H),4.07(s,3H).

[0054] Example 3 Step 3: Synthesis of Compound 4

[0055] A solution of 5-(benzyloxymethyl)-7-bromo-4-methoxy-pyrrolo[3,2-d]pyrimidine (43 g, 0.12 mol) was dissolved in anhydrous methyl tert-butyl ether (600 mL) and anisole (200 mL). The mixture was cooled to -78°C and n-BuLi (2.5 M in tetrahydrofuran, 74 mL) was added dropwise under nitrogen. Stirring was continued for 0.5 h. A solution of rac-(3aR,6aR)-6-[[tert-butyl(dimethyl)silyl]oxymethyl]-2,2-dimethyl-6,6a-dihydro-3aH-furan[3,4-d][1,3]dioxol-4-one (44.8 g, 0.15 mol) in methyl tert-butyl ether (300 mL) was added dropwise to the above mixture. After the addition was complete, the reaction solution was stirred at -78°C for 2 h. The reaction was quenched with saturated aqueous ammonium chloride (1.8 L). The aqueous phase was extracted with ethyl acetate (800 mL × 3). The combined organic phase was washed with brine (800 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The product was purified by flash silica gel chromatography ( 120g The product was purified by silica gel flash column, 0-100% ethyl acetate / petroleum ether gradient elution, 80 mL / min) to give the compound [5-(benzyloxymethyl)-4-methoxy-pyrrolo[3,2-d]pyrimidin-7-yl]-[rac-(4R,5R)-5-[2-[tert-butyl(dimethyl)silyl]oxo-1-hydroxy-ethyl]-2,2-dimethyl-1,3-dioxolan-4-yl]methanone (24 g, purity 80%, yield 27.2%) as a light yellow oil.

[0056] MS (ESI) M / Z: 572.3 [M+H] + .

[0057] 1 H NMR:ET86557-51-P1A;

[0058] 1 H NMR(DMSO-d6,400MHz)δ8.46(s,1H),7.81(s,1H),7.36-7.21(m,5H),5.75(s,2H),4.75-4.62(m,1H),4 .45(s,2H),4.10-3.99(m,2H),3.70-3.65(m,1H),1.20(s,3H),1.17(s,3H),0.90(s,9H),0.09(s,6H).

[0059] Condition optimization:

[0060]

[0061] It can be seen that in the preparation process of compound 4, the reaction solvent and reaction temperature have a very large impact on whether the target product compound 4 can be prepared. Only by using methyl tert-butyl ether / anisole as the solvent and at -78°C can compound 4 with higher purity be prepared.

[0062] Example 4 Step 4: Synthesis of Compound 5

[0063] To a solution of [5-(benzyloxymethyl)-4-methoxy-pyrrolo[3,2-d]pyrimidin-7-yl]-[rac-(4R,5R)-5-[2-[tert-butyl(dimethyl)silyl]oxo-1-hydroxy-ethyl]-2,2-dimethyl-1,3-dioxol-4-yl]methanone (10 g, 17 mmol) in ethanol (100 mL) was added sodium borohydride (0.66 g, 17 mmol) in portions at 0°C. The reaction mixture was stirred at 25°C for 1 h. The reaction was quenched with purified water (100 mL), and the aqueous phase was extracted with ethyl acetate (150 mL x 3). The combined organic phases were washed with brine (150 mL), dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo to afford 2-[tert-butyl(dimethyl)silyl]oxo-1-[rac-(4R,5S)-5-[[5-(benzyloxymethyl)-4-methoxy-pyrrolo[3,2-d]pyrimidin-7-yl]-hydroxy-methyl]-2,2-dimethyl-1,3-dioxolan-4-yl]ethanol (9 g, 85% purity, 76.2% yield) as a colorless oil. This was used directly in the next reaction without purification.

[0064] MS (ESI) M / Z: 574.3 [M+H] + .

[0065] 1 HNMR(DMSO-d6,400MHz)δ8.50(s,1H),7.33-7.24(m,5H),7.06(s,1H),5.84(d,J=10.8Hz,1H) ,5.67(d,J=11.0Hz,1H),5.18(dd,J=7.2,6.0Hz,1H),4.70(dt,J=11.9,0.9,0.9Hz,1H),4.60 (dt,J=12.0,0.9,0.9Hz,1H),4.51(dd,J=7.2,4.8Hz,1H),4.12-4.03(m,1H),3.81-3.68(m,5 H),3.64-3.58(m,2H),3.20-3.14(m,1H),1.36(s,3H),1.25(s,3H),0.89(s,9H),0.06(s,6H).

[0066] Example 5 Step 5: Synthesis of Compound 6

[0067] To a solution of 2-[tert-butyl(dimethyl)silyl]oxy-1-[rac-(4R,5S)-5-[[5-(benzyloxymethyl)-4-methoxy-pyrrolo[3,2-d]pyrimidin-7-yl]-hydroxy-methyl]-2,2-dimethyl-1,3-dioxolan-4-yl]ethanol (7.8 g, 13.6 mmol) in anhydrous dimethyl sulfoxide (40 mL) was added 2-iodoacetylbenzoic acid (22.8 g, 81.6 mol). The reaction mixture was stirred at 37°C for 12 h. The reaction was quenched with purified water (50 mL), and the aqueous phase was extracted with ethyl acetate (55 mL x 3). The combined organic phases were washed with brine (55 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give compound 2-[tert-butyl(dimethyl)silyl]oxy-1-[rac-(4S,5R)-5-[5-(benzyloxymethyl)-4-methoxy-pyrrolo[3,2-d]pyrimidine-7-carbonyl]-2,2-dimethyl-1,3-dioxolan-4-yl]ethanone (7.5 g, 70% purity, 67.6% yield) as a light yellow oil.

[0068] MS (ESI) M / Z: 570.2 [M+H] + .

[0069] 1 H NMR:ET88364-6-P1A;

[0070] 1 H NMR(DMSO-d6,400MHz)δ8.64(s,1H),8.62(s,1H),7.25-7.21(m,5H),6.22(d,J=7.6Hz,1H),5.83(s,2H),5.14(d,J=7.2Hz,1H),4 .54(s,2H),4.43(s,2H),4.09(s,3H),4.05(d,J=2.0Hz,1H),1.47(s,3H),1.42(s,3H),0.75(s,9H),-0.04(s,3H),-0.06(s,3H).

[0071] Example 6 Step 6: Synthesis of Compound 7

[0072] To a solution of 2-[tert-butyl(dimethyl)silyl]oxy-1-[rac-(4S,5R)-5-[5-(benzyloxymethyl)-4-methoxy-pyrrolo[3,2-d]pyrimidine-7-carbonyl]-2,2-dimethyl-1,3-dioxol-4-yl]ethanone (7.28 g, 12.8 mmol) in ethanol (100 mL) were added 4AMS (7.28 g), ammonium formate (7.75 g, 122 mmol), and sodium cyanoborohydride (4.71 g, 74.9 mmol). The reaction mixture was stirred at 25°C for 30 minutes. The reaction mixture was filtered, and purified water (80 mL) and EtOAc (100 mL) were added to the filtrate. The mixture was poured into a separatory funnel and separated. The aqueous phase was then extracted with ethyl acetate (100 mL x 2). The combined organic phases were washed with brine (100 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by flash silica gel chromatography ( 20g The product was purified by silica gel column with a gradient of 0-100% ethyl acetate / petroleum ether at 45 mL / min as the eluent to afford the compound tert-butyl-dimethyl-[[rac-(3aS,4S,6R,6aR)-4-[5-(benzyloxymethyl)-4-methoxy-pyrrolo[3,2-d]pyrimidin-7-yl]-2,2-dimethyl-4,5,6,6a-tetrahydro-3aH-[1,3]dioxo[4,5-c]pyrrol-6-yl]methoxy]silane (2.5 g, purity 90%, yield 33.0%) as a light yellow oil.

[0073] MS (ESI) M / Z: 555.2 [M+H] + .

[0074] 1 H NMR:ET88364-8-P1A;

[0075] 1 H NMR (CDCl3, 400MHz) δ8.45 (s, 1H), 7.64 (s, 1H), 7.45-7.22 (m, 7H), 5.91-5.61 (m, 2H), 4.95 (d, J = 4.8Hz ,3H),4.55(s,2H),4.13(s,3H),4.12-4.05(m,2H),1.45(s,3H),1.29(s,3H),0.95(s,9H),0.17(s,6H).

[0076] Example 7 Step 7: Synthesis of Compound 8

[0077] To a solution of tert-butyl-dimethyl-[[rac-(3aS,4S,6R,6aR)-4-[5-(benzyloxymethyl)-4-methoxy-pyrrolo[3,2-d]pyrimidin-7-yl]-2,2-dimethyl-4,5,6,6a-tetrahydro-3aH-[1,3]dioxo[4,5-c]pyrrol-6-yl]methoxy]silane (2 g, 0.77 mmol) in methanol (10 mL) was added concentrated hydrochloric acid (12 M, 40 mL). The reaction mixture was stirred at 80° C. for 12 h. The reaction mixture was filtered and strained to dryness. The crude product was slurried with acetonitrile, filtered, and the filter cake collected to yield rac-(2R,3R,4S,5S)-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-3,4-diol (1 g, 90% purity, 82.5% yield) as a pale yellow solid. This was used directly in the next reaction without purification.

[0078] MS (ESI) M / Z: 267.1 [M+H] + .

[0079] 1 H NMR:ET88364-9-P1A;

[0080] 1 H NMR (DMSO-d6, 400MHz) δ7.98 (s, 1H), 7.80 (s, 1H), 4.83 (d, J = 4.8Hz, 1H), 4.43 (dd ,J=4.2,7.2Hz,1H),4.24(t,J=4.4Hz,1H),3.76-3.73(m,2H),3.67-3.64(m,2H).

[0081] Example 8 Step 8: Synthesis of Compound 9

[0082] To a solution of rac-(2R,3R,4S,5S)-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-3,4-diol (0.96 g, 3.2 mmol) in methanol (48 mL) and water (24 mL) were added triethylamine (1.28 g) and Boc anhydride (1.38 g, 6.34 mmol), respectively. The reaction mixture was stirred at 25°C for 30 minutes. The reaction mixture was concentrated under reduced pressure, and the crude product, rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate, was dissolved in pyridine (1.79 mL). DMAP (7.75 mg, 63.4 μmol) and acetic anhydride (1.13 g, 11.1 mmol) were added, respectively. The reaction mixture was stirred at 25°C for 12 h. The reaction mixture was diluted with purified water (20 mL) and extracted with ethyl acetate (30 mL x 3). The combined organic layers were washed with brine (35 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain a residue. The crude product was purified by silica gel column chromatography to give the compound tert-butyl rac-(2R,3R,4S,5S)-3,4-diacetoxy-2-(acetoxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate (600 mg, purity 92.8%, yield 38.4%) as a white solid.

[0083] MS (ESI) M / Z: 493.2 [M+H] + .

[0084] 1 H NMR:ET88364-13-P1A;

[0085] 1 H NMR(DMSO-d6,400MHz)δ11.97(s,1H),11.82(d,J=2.4Hz,1H),7.76(d,J=3.2Hz,1H),7.19(s,1H),5.50(d,J=6.0Hz,2H) ,5.37(d,J=5.2Hz,1H),4.56-4.46(m,1H),4.37(d,J=6.4Hz,2H),2.00(d,J=7.2Hz,6H),1.75(s,3H),1.27-0.95(m,9H).

[0086] Example 9 Step 9: Synthesis of Compound 10

[0087] To a solution of tert-butyl (2R,3R,4S,5S)-3,4-diacetoxy-2-(acetoxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate (340 mg, 690 μmol) in acetonitrile (15 mL) were added benzyl(triethyl)ammonium chloride (314 mg, 1.38 mmol), N,N-dimethylaniline (125 mg, 1.04 mmol), and phosphorus oxychloride (635 mg, 4.14 mmol), respectively. After stirring, a clear, pale yellow solution was obtained. The reaction mixture was slowly heated to 80°C and maintained at this temperature for 10 minutes. After cooling to room temperature, the phosphorus oxychloride was removed by concentration under reduced pressure. The residue was quenched with warm water (10 mL), dissolved in 10 mL of chloroform, and washed rapidly and carefully with saturated aqueous sodium bicarbonate until the pH reached neutral. The organic layer was separated, washed with water (10 mL), brine (10 mL), dried over sodium sulfate, filtered and concentrated under reduced pressure to give the crude product. 4g The residue was purified by silica gel column, 0-100% ethyl acetate / petroleum ether gradient elution, 35 mL / min) to obtain the compound tert-butyl (2R,3R,4S,5S)-3,4-diacetoxy-2-(acetoxymethyl)-5-(4-chloro-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate (110 mg, purity 92.75%, yield 31.2%) as a white solid.

[0088] MS (ESI) M / Z: 511.2 [M+H] + .

[0089] 1 H NMR:ET88364-18-P1A;

[0090] 1 H NMR(DMSO-d6,400MHz)δ12.40(s,1H),8.60(s,1H),7.83(s,1H),5.61-5.50(m,3H) ,4.65-4.55(m,1H),4.47-4.36(m,2H),2.00(d,J=12.8Hz,9H),1.20-0.84(m,9H).

[0091] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a calisvir intermediate, characterized in that: The galisvir intermediate is shown in compound 10: The preparation method comprises the following steps: 1) Compound 7 was hydrolyzed under acidic conditions to obtain compound 8; 2) Compound 8 reacts with Boc anhydride and acetic anhydride in sequence to obtain compound 9; 3) Compound 9 reacts with a chlorinating agent to obtain the galisvir intermediate compound 10; ； In step 1), alcohol is used as the solvent, and the mass volume ratio of compound 7 to alcohol is (0.5-5) g / 10 mL. Concentrated acid is used to provide acidity, and the volume mass ratio of the concentrated acid to compound 7 is (10-30) mL:1 g. The hydrolysis reaction conditions in step 1) are: reaction at 70-90° C. for 8-15 hours. The preparation process of compound 7 is as follows: ； The preparation process of compound 3 is as follows: ； In step A, tetrahydrofuran is used as the solvent and sodium hydride is used as the catalyst; the mass volume ratio of compound 1 to the solvent is 1 g: (10-20) mL, the molar ratio of compound 1 to the catalyst is 1:1-3; the molar ratio of compound 1 to compound R01 is 1:1-2; the reaction conditions are -10-10°C for 1-4 hours; In step B, methanol is used as the solvent and sodium methoxide is used as the catalyst; the mass volume ratio of compound 2 to the solvent is 1 g: (5-20) mL, and the molar ratio of compound 2 to the catalyst is 1:1-2; the reaction conditions are room temperature for 2-6 hours.

2. The preparation method according to claim 1, wherein The alcohol is selected from methanol, ethanol, propanol or n-butanol; the concentration of the concentrated acid in step 1) is 10-15M, and the concentrated acid is selected from concentrated hydrochloric acid and / or concentrated sulfuric acid.

3. The preparation method according to claim 1, wherein In step 2), compound 8 reacts with Boc anhydride to obtain rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate, and rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate reacts with acetic anhydride to obtain compound 9.

4. The preparation method according to claim 3, wherein In step 2), the molar ratio of compound 8 to Boc anhydride is 1:1-5; the molar ratio of compound 8 to acetic anhydride is 1:2-6.

5. The preparation method according to claim 3, wherein In step 2), solvent 1 and catalyst 1 are used for the reaction of compound 8 with Boc anhydride. The mass volume ratio of compound 8 to solvent 1 is 1 g: (50-100) mL, and the mass ratio of compound 8 to catalyst 1 is 1:0.5-3. The solvent 1 is selected from at least one of methanol, ethanol, propanol, n-butanol and water. The catalyst 1 is triethylamine. The reaction conditions of compound 8 and Boc anhydride are: reaction at room temperature for 20-60 min.

6. The preparation method according to claim 3, wherein In step 2), solvent 2 and catalyst 2 are used for the reaction of rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate with acetic anhydride. The volume mass ratio of solvent 2 to compound 8 is (1-5) mL:1 g; the molar ratio of compound 8 to catalyst 2 is 1:0.005-0.05; the solvent 2 is pyridine, and the catalyst 2 is DMAP. The reaction conditions of rac-(2R,3R,4S,5S)-3,4-dihydroxy-2-(hydroxymethyl)-5-(4-hydroxy-5H-pyrrolo[3,2-d]pyrimidin-7-yl)pyrrolidine-1-carboxylate and acetic anhydride are as follows: reaction at room temperature for 8-15 hours.

7. The preparation method according to claim 1, wherein In step 3), the chlorinating agent is selected from benzyl (triethyl) ammonium chloride; the molar ratio of compound 9 to the chlorinating agent is 1:1-4; and the reaction conditions are 70-90° C. for 5-30 min.

8. The preparation method according to claim 1, wherein In step 3), solvent 3 and catalyst 3 are used when compound 9 reacts with a chlorinating agent. The mass volume ratio of compound 9 to solvent 3 is 1 g: (30-100) mL, and the molar ratio of compound 9 to catalyst 3 is 1:5-10. The solvent 3 is acetonitrile; and the catalyst 3 is N,N-dimethylaniline and / or phosphorus oxychloride.

9. The preparation method according to claim 1, wherein In step S1, anhydrous methyl tert-butyl ether and anisole in a volume ratio of 2-4:1 are used as a solvent, and a n-butyl lithium tetrahydrofuran solution with a molar concentration of 1-4 M is used as a catalyst; the mass volume ratio of compound 3 to the solvent is 1 g: (15-30) mL, and the mass volume ratio of compound 3 to the catalyst is 1 g: (1.5-2) mL; the molar ratio of compound 3 to compound R02 is 1:1-2; and the reaction conditions are -78°C for 1-3 hours.

10. The preparation method according to claim 1, wherein In step S2, ethanol is used as the solvent and sodium borohydride is used as the catalyst; the mass volume ratio of compound 4 to the solvent is 1 g: (5-15) mL, and the molar ratio of compound 4 to the catalyst is 1:0.8-1.5; the reaction conditions are room temperature for 30-120 min; in step S3, dimethyl sulfoxide is used as the solvent and 2-iodoacylbenzoic acid is used as the catalyst; the mass volume ratio of compound 5 to the solvent is 1 g: (5-15) mL, and the molar ratio of compound 5 to the catalyst is 1:4-8; the reaction conditions are 35-40° C. for 8-15 h; in step S4, ethanol is used as the solvent, and 4AMS, ammonium formate and sodium cyanoborohydride in a mass ratio of 1-2:1-2:1 are used as the catalyst; the mass volume ratio of compound 6 to the solvent is 1 g: (5-15) mL, and the mass ratio of compound 6 to the catalyst is 1:2-4; the reaction conditions are room temperature for 20-40 min.

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