A process for the preparation of alkylated nucleosides, nucleotides, oligonucleotides and analogs thereof

Abstract

This invention provides a method for preparing alkylated nucleosides, nucleotides, oligonucleotides, or their analogues, comprising the following steps: reacting a nucleoside substrate with R... 2 B(OH)2 or R 2 BF3K is dissolved in a solvent, then an oxidant and additives are added, and the reaction is carried out under light or non-light conditions to obtain the product; wherein, the nucleoside substrate is a nucleoside, nucleotide, oligonucleotide, or analogue thereof; the R 2 B(OH)2 or R 2 In BF3K, R 2 The following groups are selected from alkyl, alkoxy, aralkyl, cycloalkyl, alkenyl, alkynyl, alkyl halogen, and the following groups: This invention designs a new route for synthesizing alkylated nucleosides, nucleotides, oligonucleotides, and their analogues, using nucleosides, nucleotides, oligonucleotides, and their analogues as raw materials, through C-H bond functionalization reactions. This preparation method is simple, easy to operate, and uses mild reaction conditions, avoiding harsh high-temperature conditions and the use of toxic reagents, making it environmentally friendly.

Description

Technical Field

[0001] This invention relates to the fields of chemistry and medicine, specifically to a method for preparing alkylated nucleosides, nucleotides, oligonucleotides and their analogues. Background Technology

[0002] Nucleosides, nucleotides, oligonucleotides, and their analogues have attracted widespread attention due to their excellent antiviral and antitumor activities. Alkylated nucleoside compounds possess unique physiological activities: for example, 8-methyladenine nucleoside can inhibit vaccinia virus, and 8-ethyladenine nucleoside can treat infections caused by respiratory syncytial virus (J.Med.Chem.1993,36,2938-2942). C-8 substituted guanosines can selectively inhibit the polymerization of FtsZ, a key protein in cell division, without affecting the assembly of eukaryotic homologous tubulin (J.Am.Chem.Soc.2013,135,16418-16428). NBT1 analogues obtained from C-8 cyclopentanamino-substituted purine nucleosides have excellent inhibitory effects on nucleoside transporters (J.Med.Chem.2006,49,2861-2867). Introducing an alkyl chain at the C-8 position can inhibit amino acid amidation without inhibiting aminoacyl-tRNA, exhibiting excellent selectivity. 5-Ethyldeoxyuridine is an FDA-approved antiviral drug for herpes simplex virus, and it also possesses antitumor activity (J.Med.Chem.1986,29,494-499). Alkylated nucleosides can also treat or prevent hosts exhibiting infection or abnormal cell proliferation caused by Flaviviridae, Orthomyxoviridae, or Paramyxoviridae viruses (CN1646141A). With the emergence of increasingly novel viruses and the increasing drug resistance and mutations of existing viruses, existing nucleoside analogues are far from meeting therapeutic needs. Furthermore, sudden outbreaks of viral infections highlight the importance of developing broad-spectrum nucleoside antiviral drugs. Therefore, the synthesis of alkylated nucleoside analogues provides an important pathway for finding antiviral and antitumor drugs.

[0003] Currently, the main methods for synthesizing alkyl-substituted nucleoside analogs include: 1) Traditional transition metal-catalyzed cross-coupling reactions (Chem. Commun. 2003, 68, 837-848, etc.). However, this method has the following disadvantages: firstly, it requires pre-activation of one of the two reactants, which greatly reduces the atom economy of the reaction; secondly, the organometallic catalytic system has disadvantages such as high temperature, the need for noble metals, and sensitivity to water. 2) Through CH heterocyclic alkylation reaction (CN104478883A). However, this reaction needs to be carried out at 70℃, and the substrate range is limited to tetrahydrofuran compounds, and the substrate base purine derivatives do not even have the basic sugar ring structure of nucleosides. 3) By first alkenylating and then reducing the alkenyl group to an alkyl group. However, it requires the use of tin reagents or mercury-containing reagents and the reaction steps are relatively long (Collect.Czech.Chem.Commun.1991,56,1944-1947.J.Am.Chem.Soc.1978,100,8106-8112).

[0004]

[0005] With the rapid development of international research and production of nucleic acid-based new drugs, the demand for alkylated nucleosides is increasing. Therefore, it is necessary to address the problems of complex synthesis processes, demanding reaction conditions, and high costs associated with the synthesis of these compounds. Finding a low-cost method with mild reaction conditions and fewer reaction steps to synthesize new alkylated nucleoside analogs with potential pharmacological activity is of great significance. This method could provide raw materials for the research of antiviral and antitumor drugs, while also offering an effective method for the alkylation of other nucleosides and their analogs, and has broad industrial application prospects. Summary of the Invention

[0006] To address the problems of expensive raw materials, complex processes, and harsh reaction conditions in the preparation of alkylated nucleosides in existing technologies, this invention provides a method for preparing alkylated nucleosides, nucleotides, oligonucleotides, and their analogues. This method is characterized by mild conditions, low cost, and high atom economy.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing alkylated nucleosides, nucleotides, oligonucleotides, or analogues thereof, comprising the following steps: reacting a nucleoside substrate with R... 2 B(OH)2 or R 2 BF3K is dissolved in a solvent, and then an oxidant and additives are added. The mixture is reacted under light or non-light conditions to obtain alkylated nucleosides, nucleotides, oligonucleotides or their analogues.

[0009] The nucleoside substrate is a nucleoside, nucleotide, oligonucleotide, or analogue thereof;

[0010] The R 2 B(OH)2 or R 2 In BF3K, R 2 Selected from alkyl, alkoxy, aralkyl, cycloalkyl, alkenyl, alkynyl, alkyl halogen and the following groups:

[0011]

[0012] Preferably, the solvent is one or more of acetonitrile (MeCN), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), and water;

[0013] The amount of solvent added is 2 to 20 millimoles per millimole of nucleoside substrate.

[0014] Preferably, the oxidant is (NH4)2S2O8, K2S2O8, or Ce(SO4). 2, One or more of Cu(OAc)2·H2O; adding an oxidizing agent to the reaction can directly oxidize R. 2 B(OH)2 or R 2 BF3K forms free radicals, and on the other hand, it can oxidize photosensitizers under the condition of adding photosensitizers, promote the generation of free radicals, and shorten the reaction time.

[0015] The molar ratio of the nucleoside substrate to the oxidant is 1:0.5 to 3. More preferably, the molar ratio is 1:2.

[0016] Preferably, the additive is one or more of magnesium chloride, trifluoroacetic acid (TFA), zinc chloride, and catechol; adding the additive during the reaction can activate the substrate and improve the yield. More preferably, it is catechol, because catechol reacts with R... 2 B(OH)2 or R 2 BF3K can combine to generate free radical precursors with lower oxidation potential (e.g., alkyl borates can generate alkyl catechol borate esters), thereby obtaining higher yields.

[0017] The molar ratio of the nucleoside substrate to the additive is 1:0.1 to 3. More preferably, the molar ratio is 1:2 to 3.

[0018] Preferably, the R 2 B(OH)2 or R 2 The molar ratio of BF3K to the nucleoside substrate is 1:1 to 5. More preferably, the molar ratio is 1:2 to 4.

[0019] Preferably, the reaction under light conditions further includes the step of adding a photosensitizer before the reaction.

[0020] Preferably, the photosensitizer is one or more of MesAcr, Ir[dF(CF3)ppy]2(dtbbpy)PF6, Ru(bpy)3(PF6)2, Ru(bpz)3(PF6)2, Ru(DMB)3(PF6)2, and Eosin Y;

[0021] The amount of photosensitizer added is 3.0 to 5.0% of the molar mass of the nucleoside substrate; more preferably, it is 1:5.0%.

[0022] Preferably, the illumination conditions are achieved using 30-100W LED lights. More preferably, 36-85W LED lights are used.

[0023] Preferably, the reaction is carried out in a nitrogen atmosphere at room temperature for 5–24 hours. More preferably, the reaction is carried out for 12–24 hours.

[0024] Secondly, the present invention provides an alkylated nucleoside, nucleotide, oligonucleotide or analogue prepared according to the foregoing method, with a structure as shown in general formula (I) or (II) or (III) or (IV) or (V) or (VI) or (VII):

[0025]

[0026] Wherein, X is selected from H, F, Cl, Br, I, NH2, NHOH, OH, N3, CN, CF3, aryl, alkyl, alkoxy, aralkyl, cycloalkyl, alkenylalkyl, alkynylalkyl, alkyl halogen and the following groups:

[0027]

[0028] Y is selected from H, F, Cl, Br, I, NH2, NHOH, OH, N3, CN, CF3;

[0029] R 2 Selected from alkyl, alkoxy, aralkyl, cycloalkyl, alkenyl, alkynyl, alkyl halogen and the following groups:

[0030]

[0031]

[0032] R 1 Selected from the following groups:

[0033]

[0034] Of the above groups, R3 and R 4 Each is selected from OH, H, F, Cl, Br, I, OMe, OEt, OCH2CH2OCH3, OAc, and N3;

[0035] R 5 Selected from H, OH, ODMTr, OAc; Z is selected from S or O;

[0036] R 6 Selected from alkyl, alkoxy, aralkyl, cycloalkyl, alkenyl, alkynyl, alkyl halogen and the following groups:

[0037] Oligonucleotides are artificially modified and / or unmodified oligonucleotides containing 2-10 bases.

[0038] It should be noted that, in the above groups, A / T / C / G / U represents that the base connected thereto is any one or more of A, T, C, G, and U.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] This invention presents a novel pathway for the synthesis of alkylated nucleosides, nucleotides, oligonucleotides, and their analogues. Using nucleosides, nucleotides, oligonucleotides, and their analogues as raw materials, alkylated nucleosides, nucleotides, oligonucleotides, and their analogues are synthesized through CH bond functionalization reactions. The preparation method of this invention is simple, easy to operate, and uses mild reaction conditions, avoiding harsh high-temperature conditions and the use of toxic reagents, thus being environmentally friendly. Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0042] The following examples provide a method for preparing alkylated nucleosides, nucleotides, oligonucleotides, or their analogues, comprising the following steps:

[0043] Nucleoside substrate and R 2 B(OH)2 or R 2 BF3K is dissolved in a solvent, and then an oxidant and additives are added. The mixture is reacted under light or non-light conditions to obtain alkylated nucleosides, nucleotides, oligonucleotides or their analogues.

[0044] The nucleoside substrate is a nucleoside, nucleotide, oligonucleotide, or analogue thereof;

[0045] The R 2 B(OH)2 or R 2 In BF3K, R 2 Selected from alkyl, alkoxy, aralkyl, cycloalkyl, alkenyl, alkynyl, alkyl halogen and the following groups:

[0046]

[0047] The solvent is one or more of acetonitrile (MeCN), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), and water; the amount of solvent added is 2 to 20 ml per millimole of nucleoside substrate.

[0048] The oxidant is (NH4)2S2O8 or K2S2O. 8, Ce(SO4) 2, One or more of Cu(OAc)2·H2O; the molar ratio of the nucleoside substrate to the oxidant is 1:0.5-3.

[0049] The additive is one or more of magnesium chloride, trifluoroacetic acid, zinc chloride, and catechol; the molar ratio of the nucleoside substrate to the additive is 1:0.1-3.

[0050] The nucleoside substrate and R 2 B(OH)2 or R 2 The molar ratio of BF3K is 1:1 to 5.

[0051] The reaction under light conditions also includes the step of adding a photosensitizer before the reaction.

[0052] The photosensitizer is one or more of MesAcr, Ir[dF(CF3)ppy]2(dtbbpy)PF6, Ru(bpy)3(PF6)2, Ru(bpz)3(PF6)2, Ru(DMB)3(PF6)2, and Eosin Y; the amount of photosensitizer added is 3.0 to 5.0% of the molar mass of the nucleoside substrate.

[0053] The lighting conditions are provided by using 30-100W LED lights.

[0054] The reaction was carried out in a nitrogen atmosphere under the condition of 5–24 h at room temperature.

[0055] Under the above conditions, the corresponding alkylated nucleosides, nucleotides, oligonucleotides or their analogues can be prepared.

[0056] The reaction principle for preparing alkylated nucleosides, nucleotides, oligonucleotides, or their analogues in this invention is as follows:

[0057] R is oxidized by oxidant 2 B(OH)2 or R 2 BF3K, generates R 2 Free radicals, making R 2 Free radicals undergo radical addition reactions with nucleoside substrates to yield a series of products; under light conditions, the added photosensitizer is oxidized by the oxidant, and then forms an excited state under light, reacting with R... 2 B(OH)2 or R 2 BF3K undergoes a single-electron transfer to generate R. 2 Free radicals can promote R under light. 2 The faster generation of free radicals can shorten the reaction time.

[0058] Based on the above reaction principle, this invention can not only prepare alkylated nucleosides, nucleotides, oligonucleotides or their analogues as shown in the following general formulas (I) or (II) or (III) or (IV) or (V) or (VI) or (VII):

[0059]

[0060] Wherein, X is selected from H, F, Cl, Br, I, NH2, NHOH, OH, N3, CN, CF3, phenyl, alkyl, alkoxy, aralkyl, cycloalkyl, alkenylalkyl, alkynylalkyl, alkyl halogen and the following groups:

[0061]

[0062] Y is selected from H, F, Cl, Br, I, NH2, NHOH, OH, N3, CN, CF3;

[0063] R 2 Selected from alkyl, alkoxy, aralkyl, cycloalkyl, alkenyl, alkynyl, alkyl halogen and the following groups:

[0064]

[0065]

[0066] R 1 Selected from the following groups:

[0067]

[0068] Of the above groups, R 3 and R 4 Each is selected from OH, H, F, Cl, Br, I, OMe, OEt, OCH2CH2OCH3, OAc, and N3;

[0069] R5 Selected from H, OH, ODMTr, OAc; Z is selected from S or O;

[0070] R 6 Selected from alkyl, alkoxy, aralkyl, cycloalkyl, alkenyl, alkynyl, alkyl halogen and the following groups:

[0071] Oligonucleotides are artificially modified and / or unmodified oligonucleotides containing 2-10 bases.

[0072] The method of the present invention can also be used to prepare alkylated nucleosides, nucleotides, oligonucleotides and their analogues with other known structures.

[0073] Example 1

[0074] This embodiment provides a method for preparing the compound shown in Formula 3, and the reaction formula is as follows:

[0075]

[0076] Specific preparation steps:

[0077] Add guanosine (0.2 mmol, 56.6 mg) as shown in Formula 1, potassium tert-butyltrifluoroborate (0.4 mmol, 65.6 mg) as shown in Formula 2, MesAcr (0.01 mmol, 4 mg), (NH4)2S2O8 (0.4 mmol, 91.2 mg), 15 μl TFA (0.2 mmol), 1 ml MeCN, and 1 ml H2O (as solvent) to a 10 ml Shrek tube. The reaction mixture was placed in a nitrogen atmosphere under 85 W LED illumination at room temperature for 16 hours. The reaction was monitored using a TCL. After termination, the solvent was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 56.3 mg of the target compound 8-tert-butylguanosine (as shown in Formula 3), with a yield of 82%. The obtained target compound was analyzed by proton NMR spectroscopy using a Bruker 400 MHz instrument. The characterization results are as follows: 1 H NMR (400MHz, DMSO) δ10.58(s,1H),6.20(s,2H),5.95(d,J=6.2Hz,1H),5.34(d,J=6.3Hz,1H),5.09-5.07(m,2H),4.99(d,J =5.3Hz,1H),4.17(dd,J=8.7,5.2Hz,1H),3.86(dd,J=8.1,4.4Hz,1H),3.70-3.66(m,1H),3.58-3.49(m,1H),1.39(s,9H).

[0078] Example 2

[0079] This embodiment provides a method for preparing the compound shown in Formula 5, and the reaction formula is as follows:

[0080]

[0081] The specific preparation steps are as follows:

[0082] Add guanosine (0.2 mmol, 56.6 mg) of Formula 1, ethylboric acid (0.8 mmol, 59.2 mg) of Formula 4, MesAcr (0.01 mmol, 4 mg), (NH4)2S2O8 (0.4 mmol, 91.2 mg), catechol (0.2 mmol, 22 mg), 15 μl TFA (0.2 mmol), 1 ml MeCN, and 1 ml H2O (as solvent) to a 10 ml Shrek tube. The reaction mixture was placed in a nitrogen atmosphere under 85 W LED illumination at room temperature for 16 hours. The reaction was monitored using a TCL. After termination, the solvent was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 56.6 mg of the target compound 8-ethylguanosine (Formula 5), ​​with a yield of 91%. The obtained target compound was analyzed by 1H NMR and 1C NMR using a Bruker 400 MHz NMR spectrometer. The characterization results are as follows: 1 H NMR (400MHz, DMSO) δ10.62(s,1H),6.28(s,2H),5.64(d,J=6.7Hz,1H),5.33(d,J=6.7Hz,1H),5.17-5.11(m,1H),5.09-5.07(m,1H),4.76 (dd,1H),4.11-4.07(m,1H),3.86(dd,J=7.4,3.9Hz,1H),3.66-3.61(m,1H),3.55-3.49(m,1H),2.75-2.69(m,2H),1.22(t,J=7.4Hz,3H). 13 C NMR (100MHz, DMSO) δ156.4,152.9,151.8,149.6,115.6,87.7,85.7,71.2,70.6,62.01,20.8,11.8.

[0083] Example 3

[0084] This embodiment provides a method for preparing the compound shown in Formula 5, and the reaction formula is as follows:

[0085]

[0086] The specific preparation steps are as follows:

[0087] In a 10 ml Shrek tube, guanosine (0.2 mmol, 56.6 mg) of Formula 1, ethylboric acid (0.8 mmol, 59.2 mg) of Formula 4, (NH4)2S2O8 (0.4 mmol, 91.2 mg), catechol (0.2 mmol, 22 mg), 15 μl TFA (0.2 mmol), 1 ml MeCN, and 1 ml H2O (as solvent) were added. The reaction mixture was reacted at room temperature for 12 hours under nitrogen protection. The reaction was monitored using a TCL. After termination of the reaction, the solvent in the reaction mixture was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 56.6 mg of the target compound 8-ethylguanosine (Formula 5), ​​with a yield of 91%.

[0088] Example 4

[0089] This embodiment provides a method for preparing the compound shown in Formula 7, and the reaction formula is as follows:

[0090]

[0091] The specific preparation steps are as follows:

[0092] Add guanosine (0.2 mmol, 56.6 mg) of Formula 1, cyclobutylboronic acid (0.4 mmol, 40 mg) of Formula 6, MesAcr (0.01 mmol, 4 mg), (NH4)2S2O8 (0.4 mmol, 91.2 mg), catechol (0.2 mmol, 22 mg), 15 μl TFA (0.2 mmol), 1 ml MeCN, and 1 ml H2O (as solvent) to a 10 ml Shrek tube. The reaction mixture was reacted at room temperature under nitrogen protection using an 85W LED for 16 hours. The reaction was monitored using a TCL. After termination, the solvent was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 53.9 mg of the target compound 8-cyclobutylguanosine (Formula 7), with a yield of 80%. The obtained target compound was analyzed by 1H NMR and 1C NMR using a Bruker 400 MHz NMR spectrometer. The characterization results are as follows: 1HNMR (400MHz, DMSO) δ10.63 (s, 1H), 6.29 (s, 2H), 5.52 (d, J = 6.8 Hz, 1H), 5.30 (d, J = 6. 6Hz,1H),5.16(dd,J=7.0,4.8Hz,1H),5.07(d,J=4.6Hz,1H),4.71(dd,J=12.3,6.3Hz, 1H),4.10(d,J=2.6Hz,1H),3.86(dd,J=7.2,4.1Hz,1H),3.73-3.61(m,2H),3.57-3.5 1(m,1H),2.45-2.34(m,1H),2.33-2.18(m,3H),2.01-1.99(m,1H),1.92-1.82(m,1H). 13 C NMR (100MHz, DMSO) δ156.8,153.3,152.2,151.4,116.2,88.1,86.2,71.7,71.0,62.5,32.2,27.3,27.1,18.3.

[0093] Example 5

[0094] This embodiment provides a method for preparing the compound shown in Formula 9, and the reaction formula is as follows:

[0095]

[0096] The specific preparation steps are as follows:

[0097] In a 10 ml Shrek tube, uridine (0.2 mmol, 48.8 mg) as shown in Formula 8, ethylboric acid (0.8 mmol, 59.2 mg) as shown in Formula 4, (NH4)2S2O8 (0.4 mmol, 91.2 mg), MgCl2 (0.2 mmol, 19.1 mg), catechol (0.4 mmol, 44.4 mg), 0.4 ml DMSO, and 0.4 ml H2O were added. The reaction mixture was reacted at room temperature under nitrogen protection using a 36W blue LED for 12 hours. The reaction was monitored using a TCL. After termination of the reaction, the solvent in the reaction mixture was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 40.8 mg of the target compound 5-ethyluridine as shown in Formula 9, with a yield of 75%.

[0098] Example 6

[0099] This embodiment provides a method for preparing the compound shown in Formula 11, and the reaction formula is as follows:

[0100]

[0101] The specific preparation steps are as follows:

[0102] In a 10 ml Shrek tube, uridine (0.2 mmol, 48.8 mg) as shown in Formula 8, potassium isopropyltrifluoroborate (0.8 mmol, 120.0 mg) as shown in Formula 10, (NH4)2S2O8 (0.4 mmol, 91.2 mg), MgCl2 (0.2 mmol, 19.1 mg), catechol (0.4 mmol, 44.4 mg), 0.4 ml DMSO, and 0.4 ml H2O were added. The reaction mixture was reacted at room temperature under nitrogen protection with a 36 W blue LED for 12 hours. The reaction was monitored with a TCL. After the reaction was terminated, the solvent in the reaction mixture was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 38.3 mg of the target compound 5-isopropyluridine as shown in Formula 11, with a yield of 67%.

[0103] Example 7

[0104] This embodiment provides a method for preparing the compound shown in Formula 13, and the reaction formula is as follows:

[0105]

[0106] The specific preparation steps are as follows:

[0107] In a 10 ml Shrek tube, uridine (0.2 mmol, 48.8 mg) as shown in Formula 8, cyclohexylboronic acid (0.8 mmol, 102.4 mg) as shown in Formula 12, (NH4)2S2O8 (0.4 mmol, 91.2 mg), MgCl2 (0.2 mmol, 19.1 mg), catechol (0.4 mmol, 44.4 mg), 0.4 ml DMSO, and 0.4 ml H2O were added. The reaction mixture was reacted at room temperature under nitrogen protection with a 36 W blue LED for 12 hours. The reaction was monitored with a TCL. After the reaction was terminated, the solvent in the reaction solution was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 51.5 mg of the target compound 5-cyclohexyluridine as shown in Formula 13, with a yield of 79%.

[0108] Example 8

[0109] This embodiment provides a method for preparing the compound shown in Formula 15, and the reaction formula is as follows:

[0110]

[0111] The specific preparation steps are as follows:

[0112] In a 10 ml Shrek tube, triacetyluridine (0.2 mmol, 74 mg) of Formula 14, ethylboric acid (0.8 mmol, 59.2 mg) of Formula 4, (NH4)2S2O8 (0.4 mmol, 91.2 mg), and catechol (0.4 mmol, 44.4 mg) were added, along with 0.8 ml of DMSO solvent. The reaction mixture was reacted at room temperature under nitrogen protection using a 36 W blue LED for 17 hours. The reaction was monitored using a TCL. After termination, the solvent in the reaction mixture was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 57.3 mg of the target compound 5-ethyltriacetyluridine (Formula 15), with a yield of 72%.

[0113] Example 9

[0114] This embodiment provides a method for preparing the compound shown in Formula 17, and the reaction formula is as follows:

[0115]

[0116] The specific preparation steps are as follows:

[0117] In a 10 ml Shrek tube, add disodium guanosine triphosphate (0.1 mmol, 52.3 mg) as shown in Formula 18, potassium isopropyltrifluoroborate (0.2 mmol, 30 mg) as shown in Formula 10, MesAcr (0.005 mmol, 2 mg), (NH4)2S2O8 (0.2 mmol, 45.6 mg), 7.5 μl TFA (0.1 mmol), 0.5 ml MeCN, and 0.5 ml H2O (as solvent). The reaction mixture was reacted at room temperature under nitrogen protection using an 85W LED for 16 hours. The reaction was monitored using LCMS. After termination, the solvent was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 40.1 mg of the target compound 8-isopropylguanosine triphosphate as shown in Formula 17, with a yield of 71%. The obtained target compound was analyzed by 1H NMR, 1C NMR, and 1P NMR spectra using a Bruker 400 MHz NMR spectra. The characterization results are as follows: 1 H NMR(400MHz,D2O)δ5.88(d,J=6.4Hz,1H),5.25(t,J=13.7,7.6Hz,1H),4.37– 4.17(m,4H),3.32-3.24(m,J=13.6,6.8Hz,1H),1.31(dd,J=6.7,2.7Hz,6H). 13 C NMR (100MHz, D2O) δ156.7,153.9,151.4,110.7,88.1,84.1,84.0 70.9,69.9,64.4,26.2,20.3,19.8. 31P NMR(162MHz,D2O)δ-5.69(d,J=19.5Hz,1P),-10.76(d,J=18.7Hz,1P),-21.29(t,J=19.1Hz,1P).

[0118] Example 10

[0119] This embodiment provides a method for preparing the compound shown in Formula 19, and the reaction formula is as follows:

[0120]

[0121] The specific preparation steps are as follows:

[0122] In a 10 mL Shrek tube, the following compounds were added: compound of formula 18 (0.1 mmol, 52.3 mg), ethylboric acid of formula 4 (0.4 mmol, 30 mg), MesAcr (0.005 mmol, 2 mg), (NH4)2S2O8 (0.2 mmol, 45.6 mg), catechol (0.1 mmol, 11 mg), 7.5 μl TFA (0.1 mmol), 0.5 mL MeCN, and 0.5 mL H2O (as solvent). The reaction mixture was reacted at room temperature under nitrogen protection with an 85 W LED for 24 hours. The reaction was monitored by LCMS. After termination, the solvent was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 45.0 mg of the target compound of formula 19, with a yield of 73%. The target compound was analyzed by proton, carbon, and phosphorus NMR spectra using a Bruker 400 MHz NMR spectra. The characterization results are as follows: 1 H NMR(400MHz,D2O)δ7.86(d,J=8.1Hz,1H),5.93-5.85(m,3H),5.04(t,J=5.9Hz,1H),4.91-4.84(m,1H),4.40-4.38(m,1H),4.37- 4.30(m,2H),4.30-4.22(m,2H),4.15-4.12(m,1H),3.92-3.89(m,1H),3.87-3.83(m,1H),2.97-2.90(m,2H),1.34-1.30(m,3H). 13 C NMR(100Hz,D2O)δ165.9,161.0,153.5,151.6,141.6,112.7,102.4,89.0,8 8.7,85.0,84.9,74.4,74.3,73.6,71.4,69.4,64.7,64.6,61.6,20.2,10.9. 31P NMR(162MHz,D2O)δ-0.51(s,1P).

[0123] Example 11

[0124] This embodiment provides a method for preparing the compound shown in Formula 21, and the reaction formula is as follows:

[0125]

[0126] The specific preparation steps are as follows:

[0127] In a 10 ml Shrek tube, the following compounds were added: compound of formula 20 (0.1 mmol, 52.3 mg), ethylboric acid of formula 4 (0.4 mmol, 30 mg), MesAcr (0.005 mmol, 2 mg), (NH4)2S2O8 (0.2 mmol, 45.6 mg), catechol (0.1 mmol, 11 mg), 7.5 μl TFA (0.1 mmol), 0.5 ml MeCN, and 0.5 ml H2O (as solvent). The reaction mixture was reacted at room temperature under nitrogen protection with an 85 W LED for 24 hours. The reaction was monitored by LCMS. After termination, the solvent was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 44.8 mg of the target compound of formula 21, with a yield of 71%. The target compound was analyzed by proton, carbon, and phosphorus NMR spectra using a Bruker 400 MHz NMR spectra. The characterization results are as follows: 1 H NMR(400MHz,D2O)δ7.66(s,1H),5.91(d,J=4.6Hz,1H),5.84(d,J=6.5Hz,1H),5.00(t,J=5.8Hz,1H),4.87-4.83(m,1H),4.39- 4.35(m,3H),4.30-4.21(m,2H),4.15-4.12(m,1H),3.90-3.80(m,2H),2.85-2.70(m,2H),1.85(s,3H),1.27(t,J=7.4Hz,3H). 13 C NMR(100MHz,D2O)δ166.2,153.1,152.9,151.7,151.6,137.1,115.3,111.6,88. 7,88.4,84.8,82.7,74.7,73.3,71.4,69.5,64.7,61.6,38.6,20.5,11.5,11.1. 31 P NMR(162MHz,D2O)δ-0.67(s,1P).

[0128] Example 12

[0129] This embodiment provides a method for preparing the compound shown in Formula 23, and the reaction formula is as follows:

[0130]

[0131] The specific preparation steps are as follows:

[0132] In a 10 mL Shrek tube, the following compounds were added: compound of formula 22 (0.1 mmol, 92.3 mg), ethylboric acid of formula 4 (0.4 mmol, 30 mg), MesAcr (0.005 mmol, 2 mg), (NH4)2S2O8 (0.2 mmol, 45.6 mg), catechol (0.1 mmol, 11 mg), 7.5 μl TFA (0.1 mmol), 0.5 mL MeCN, and 0.5 mL H2O (as solvent). The reaction mixture was reacted at room temperature under nitrogen protection using an 85 W LED for 24 hours. The reaction was monitored by LCMS. After termination of the reaction, the solvent in the reaction mixture was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 66.6 mg of the target compound of formula 23, with a yield of 70%.

[0133] Example 13

[0134] This embodiment provides a method for preparing the compound shown in Formula 25, and the reaction formula is as follows:

[0135]

[0136] The specific preparation steps are as follows:

[0137] In a 10 mL Shrek tube, the following compounds were added: compound of formula 24 (0.1 mmol, 153.5 mg), ethylboric acid of formula 4 (0.4 mmol, 30 mg), MesAcr (0.005 mmol, 2 mg), (NH4)2S2O8 (0.2 mmol, 45.6 mg), catechol (0.1 mmol, 11 mg), 7.5 μl TFA (0.1 mmol), 0.5 mL MeCN, and 0.5 mL H2O (as solvent). The reaction mixture was reacted at room temperature under nitrogen protection using an 85 W LED for 24 hours. The reaction was monitored by LCMS. After termination of the reaction, the solvent was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 107.2 mg of the target compound of formula 25, with a yield of 68%.

[0138] Example 14

[0139] This embodiment provides a method for preparing the compound shown in Formula 27, and the reaction formula is as follows:

[0140]

[0141] The specific preparation steps are as follows:

[0142] In a 10 mL Shrek tube, the following compounds were added: compound of formula 26 (0.1 mmol, 65.1 mg), ethylboric acid of formula 4 (0.4 mmol, 30 mg), MesAcr (0.005 mmol, 2 mg), (NH4)2S2O8 (0.2 mmol, 45.6 mg), catechol (0.1 mmol, 11 mg), 7.5 μl TFA (0.1 mmol), 0.5 mL MeCN, and 0.5 mL H2O (as solvent). The reaction mixture was reacted at room temperature under nitrogen protection using an 85 W LED for 24 hours. The reaction was monitored by LCMS. After termination of the reaction, the solvent in the reaction mixture was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 46.2 mg of the target compound of formula 27, with a yield of 68%.

[0143] Example 15

[0144] This embodiment provides a method for preparing the compound shown in Formula 29, and the reaction formula is as follows:

[0145]

[0146] The specific preparation steps are as follows:

[0147] In a 10 ml Shrek tube, cytidine (Formula 28) (0.2 mmol, 48.6 mg), ethylboric acid (Formula 4) (0.8 mmol, 59.2 mg), (NH4)2S2O8 (0.4 mmol, 91.2 mg), MgCl2 (0.2 mmol, 19.1 mg), catechol (0.4 mmol, 44.4 mg), 0.4 ml DMSO, and 0.4 ml H2O were added. The reaction mixture was reacted at room temperature under nitrogen protection using a 36 W blue LED for 12 hours. The reaction was monitored using a TCL. After termination of the reaction, the solvent in the reaction mixture was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 6.5 mg of the target compound, 5-ethylcytidine (Formula 29), with a yield of 12%.

[0148] Example 16

[0149] This embodiment provides a method for preparing the compound shown in Formula 5, and the reaction formula is as follows:

[0150]

[0151] The specific preparation steps are as follows:

[0152] In a 10 ml Shrek tube, guanosine (0.2 mmol, 56.6 mg) as shown in Formula 1, ethylboric acid (0.8 mmol, 59.2 mg) as shown in Formula 4, MesAcr (0.01 mmol, 4 mg), (NH4)2S2O8 (0.4 mmol, 91.2 mg), 15 μl TFA (0.2 mmol), 1 ml MeCN, and 1 ml H2O (as solvent) were added. The reaction mixture was placed in a nitrogen atmosphere under 85 W LED illumination at room temperature for 16 hours. The reaction was monitored with a TCL. After the reaction was terminated, the solvent in the reaction solution was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 8.1 mg of the target compound 8-ethylguanosine as shown in Formula 5, with a yield of 13%.

[0153] Example 17

[0154] This embodiment provides a method for preparing the compounds shown in Formulas 31, 32, and 33, with the following reaction formulas:

[0155] The specific preparation steps are as follows:

[0156] In a 10 ml Shrek tube, adenosine (0.2 mmol, 53.4 mg) of Formula 30, ethylboric acid (0.8 mmol, 59.2 mg) of Formula 4, MesAcr (0.01 mmol, 4 mg), (NH4)2S2O8 (0.4 mmol, 91.2 mg), catechol (0.2 mmol, 22 mg), 15 μl TFA (0.2 mmol), 1 ml MeCN, and 1 ml H2O (as solvent) were added. The reaction mixture was placed in a nitrogen atmosphere and the reaction tube was placed under 85 W LED light at room temperature for 16 hours. The reaction was monitored with a TCL. After the reaction was terminated, the solvent in the reaction solution was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 5.9 mg of the target compound of Formula 31 (10% yield), 17.7 mg of the target compound of Formula 32 (30% yield), and 5.9 mg of the target compound of Formula 33 (10% yield).

[0157] Example 18

[0158] This embodiment provides a method for preparing the compound shown in Formula 35, and the reaction formula is as follows:

[0159]

[0160] The specific preparation steps are as follows:

[0161] In a 10 mL Shrek tube, the following compounds were added: compound of formula 34 (0.2 mmol, 68.6 mg), ethylboric acid of formula 4 (0.8 mmol, 59.2 mg), MesAcr (0.01 mmol, 4 mg), (NH4)2S2O8 (0.4 mmol, 91.2 mg), catechol (0.2 mmol, 22 mg), 15 μl TFA (0.2 mmol), 1 mL MeCN, and 1 mL H2O (as solvent). The reaction mixture was placed in a nitrogen atmosphere under 85 W LED illumination at room temperature for 16 hours. The reaction was monitored using a TCL. After termination, the solvent in the reaction mixture was evaporated to dryness using a rotary evaporator. The residue was purified by column chromatography to obtain 44.5 mg of the target compound of formula 35, with a yield of 60%.

[0162] Example 19

[0163] The preparation method in this embodiment is basically the same as that in Example 2, except that only catechol is added in this embodiment, and trifluoroacetic acid is not added. The target compound shown in Formula 2 was thus prepared in a yield of 34.2 mg, with a yield of 55%.

[0164] It should be noted that when the compound shown in formula VI... When Y is OH, it is the compound shown in formula V of this invention. Therefore, based on the specific preparation method of this invention, the compound shown in Formula V can be prepared without a doubt. Furthermore, the method of this invention can also prepare keto-enol or amine-imine tautomers of nucleosides, which will not be listed individually in this invention.

[0165] Comparative Example 1

[0166] The preparation method of this comparative example is basically the same as that of Example 2, except that the oxidant (NH4)2S2O8 was not added in this comparative example. The target compound shown in Formula 5 was obtained in a yield of 0 mg.

[0167] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing alkylated nucleosides, characterized in that, Includes the following steps: Nucleoside substrate and R 2 B(OH)2 is dissolved in a solvent, then an oxidant and additives are added, and the reaction is carried out under light or non-light conditions to obtain alkylated nucleosides. The nucleoside substrate is guanosine; The R 2 In B(OH)2, R 2 Selected from alkyl and cycloalkyl groups; The oxidant is (NH4)2S2O8; The additive is a combination of trifluoroacetic acid and catechol; The reaction under illumination uses 85 W LED light and also includes the step of adding a photosensitizer before the reaction; the photosensitizer is one or more of MesAcr, Ir[dF(CF3)ppy]2(dtbbpy)PF6, Ru(bpy)3(PF6)2, Ru(bpz)3(PF6)2, Ru(DMB)3(PF6)2, and Eosin Y.

2. The method for preparing alkylated nucleosides according to claim 1, characterized in that, The solvent is one or more of acetonitrile, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, and water; The amount of solvent added is 2 to 20 millimoles per millimole of nucleoside substrate.

3. The method for preparing alkylated nucleosides according to claim 1, characterized in that, The molar ratio of the nucleoside substrate to the oxidant is 1:0.5 to 3.

4. The method for preparing alkylated nucleosides according to claim 1, characterized in that, The molar ratio of the nucleoside substrate to the additive is 1:0.1 to 3.

5. The method for preparing alkylated nucleosides according to claim 1, characterized in that, The nucleoside substrate and R 2 The molar ratio of B(OH)2 is 1:1 to 5.

6. The method for preparing alkylated nucleosides according to claim 1, characterized in that, The amount of photosensitizer added is 3.0 to 5.0% of the molar mass of the nucleoside substrate.

7. The method for preparing alkylated nucleosides according to claim 1, characterized in that, The reaction was carried out in a nitrogen atmosphere under the condition of 5–24 h at room temperature.

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