A pyridone compound, synthesis method and application thereof

Abstract

A pyridone compound, a synthesis method, and its application. The present invention discloses a pyridone derivative having a structure represented by Formula I, Formula II, or Formula III; the present invention also discloses a method for preparing the derivative. Studies have shown that the hydroxypyridone derivatives of the present invention have a high resistance index (RI = IC) of wild-type and PA / I38T mutant influenza virus RNA polymerase. 50 [I38T] / IC 50 [WT]) is lower than baloxavir, suggesting that the derivatives described herein are less affected by the influenza A PA / I38T mutation and are superior to baloxavir. Furthermore, these derivatives exhibit lower cytotoxicity than baloxavir and possess higher selectivity, making them suitable for the preparation of anti-influenza drugs that inhibit baloxavir-resistant strains. #imgabs0#

Description

Technical Field

[0001] The present invention belongs to the field of medicinal chemistry, and specifically relates to a pyridone compound, a synthesis method and an application thereof. Background Art

[0002] Influenza spreads rapidly among the population, with high morbidity and mortality rates. Antiviral treatment for influenza mainly relies on neuraminidase inhibitors, but drug resistance has emerged, and antiviral drugs with new mechanisms are urgently needed. In 2018, the influenza virus cap-dependent nuclease inhibitor baloxavir marboxil was approved for the treatment of acute uncomplicated influenza, which has a completely new mechanism of action. However, in recent clinical studies, baloxavir has produced a variety of different mutant virus strains. Among them, PA / I38X (I38T / M / F / L / N / S mutation) mutations account for as much as 2%-9% of patients. Conventional doses of baloxavir treatment are difficult to produce the expected therapeutic effect on influenza patients carrying the I38X mutation. There is an urgent need to develop PA inhibitors with the same level of inhibitory efficacy against wild-type and mutant influenza virus strains. The reduced sensitivity of BXA to the I38T mutation is attributed to unfavorable van der Waals stacking and induced adaptive changes in the Thr38 residue. The butterfly-shaped hydrophobic segment of BXA is PA N The hydrophobic pocket in the active site provides nearly perfect packing. However, the packing effect is slightly reduced with the presence of Thr38, which is more polar and smaller. N By changing the binding mode caused by the point mutation of the hydrophobic pocket in the active site, developing new hydrophobic fragment substituents, and then weakening the interaction between the corresponding inhibitor and the I38T mutation site, it is expected to improve its inhibitory activity against influenza PA / I38T mutant strains. Summary of the Invention

[0003] The object of the present invention is to provide a pyridone derivative, which is a hydroxypyridone derivative having 5' cap structure (CAP)-dependent endonuclease inhibitory activity.

[0004] Another object of the present invention is to provide a pyridone derivative that can simultaneously inhibit PA / WT and PA / I38T influenza viruses.

[0005] The present invention further provides a use of the compound in preparing drugs for inhibiting influenza virus RNA polymerase activity and for resisting influenza viruses.

[0006] Specifically, the structures represented by the following formula (I), formula (II) and formula (III) or their pharmaceutically acceptable salts,

[0007]

[0008] in

[0009] R1 is selected from hydrogen, halogen, alkyl (preferably C1-C6 alkyl), R1 is one or multiple independent of each other;

[0010] R2 is selected from the group consisting of: absent, alkyl (preferably C1-C6 alkyl) or alkanoyl (preferably C1-C3 alkanoyl, more preferably )or

[0011] R3 is selected from hydrogen or

[0012] R4 is selected from hydrogen or alkyl (preferably C1-C6 alkyl);

[0013] X is selected from N, O, S, Se; when X is O, S, Se, R2 does not exist;

[0014] Ring A is selected from one of the following structures:

[0015]

[0016] In the present invention, the alkyl group mentioned is generally a C1-C6 alkyl group, including but not limited to methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, etc. The alkyl group is further preferably a C1-C5 alkyl group, and further preferably a C1-C3 alkyl group, including but not limited to methyl, ethyl, and propyl.

[0017] In the present invention, the halogen mentioned includes F, Cl, Br, and I. Preferably, the halogen includes F, Cl, and Br.

[0018] Furthermore, the C atom corresponding to * in the following formula (I), formula (II) and formula (III) is in S configuration or R configuration or a mixture of S configuration and R configuration:

[0019]

[0020] R1, R2, R3, R4 and X are as defined above.

[0021] Furthermore, R1 is one, two or three independent of each other, and each R1 is independently selected from hydrogen, F, Cl, methyl, and ethyl.

[0022] Further, R2 is selected from not existing, or

[0023] Further, R3 is selected from hydrogen or

[0024] Further, R4 is selected from hydrogen or methyl, ethyl;

[0025] Furthermore, X is selected from N, O, S or Se; when X is O, S or Se, R2 does not exist.

[0026] Furthermore, the pyridone derivative has the structure shown in the following formula (Ia), (Ib), (Ic), and (III-a):

[0027]

[0028] R1 is H, halogen, C1-C3 alkyl, R1 is 1 or 2 independent of each other, R3 is H or

[0029] Furthermore, the pyridone derivative has a structure shown in any of the following formulas:

[0030]

[0031]

[0032] An intermediate for preparing the pyridone derivative described in any of the above technical solutions has a structure shown in any of the following formulas:

[0033]

[0034] R1 is selected from hydrogen, halogen, alkyl (preferably C1-C6 alkyl), R1 is one or multiple independent of each other;

[0035] R2 is selected from the group consisting of: absent, alkyl (preferably C1-C6 alkyl) or alkanoyl (preferably C1-C3 alkane, more preferably )or

[0036] R4 is selected from hydrogen or (preferably C1-C6 alkyl) alkyl;

[0037] X is selected from N, O, S or Se; when X is O, S or Se, R2 does not exist;

[0038] Ring A is selected from one of the following structures:

[0039]

[0040] Furthermore, the intermediate has a structure shown in any of the following formulas:

[0041]

[0042]

[0043] A method for synthesizing a pyridone derivative according to any of the above technical solutions, comprising: reducing a compound represented by formula (I-1) or formula (II-1) or formula (III-1) under the action of sodium borohydride to obtain an intermediate represented by formula (I-2) or formula (II-2) or formula (III-2); reacting the intermediate (I-2) or (II-2) or (III-2) with (R)-7-benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione in the presence of n-butylphosphoric anhydride to obtain an intermediate (I-3) or (II-3) or (III-3); and reducing the intermediate (I-3) or (II-3) or (III-3) with LiCl to obtain a pyridone derivative represented by formula (I) or formula (II) or formula (III):

[0044]

[0045] When preparing the intermediate of formula (I-2), formula (II-2) or formula (III-2), the solvent used is methanol or ethanol, and the molar ratio of the compound represented by formula (I-1), formula (II-1) or formula (III-1) to sodium borohydride is 1:1 to 2.5.

[0046] When preparing intermediate (I-3) or (II-3) or formula (III-3), the solvent used is ethyl acetate; the reaction temperature is 70-120°C; further, the reaction temperature is 100-120°C. The molar ratio of intermediate (I-2) or (II-2) or formula (III-2) to n-butylphosphoric anhydride and (R)-7-benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione is 1:1-1.5:0.3-0.6.

[0047] When preparing the pyridone derivative represented by formula (I), formula (II) or formula (III), the solvent used is N,N-dimethylacetamide; the reaction temperature is 60-100°C; more preferably 70-90°C; the molar ratio of the intermediate (I-3) or (II-3) formula (III-3) to LiCl is 1:2-15; further preferably 1:5-12.

[0048] Furthermore, Ring A for or When the intermediate represented by formula (II-2) first reacts with PBr3 to obtain intermediate (II-2-a):

[0049] Then, the intermediate (II-2-a) reacts with (R)-7-benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione in the presence of CsF to obtain the intermediate represented by formula (II-3).

[0050] In the above steps, when preparing the intermediate (II-2-a), the molar ratio of the intermediate represented by formula (II-2) and PBr3 is 1:1.2~2; the reaction solvent is anhydrous DCM.

[0051] When preparing the intermediate shown in (II-3), the reaction solvent is anhydrous acetonitrile; the molar ratio of (II-2-a), Cs, and (R)-7-benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione is 1:

[0052] 1.5~2.5:0.7~1.2; the reaction temperature is 50~80℃.

[0053] Going further:

[0054] When the intermediate (I-1) has a structure represented by formula (I-1-1), the intermediate (I-1) is obtained by reacting the intermediate (I-1-1-1) with tert-butyl nitrite; preferably, the reaction conditions of this step are: the reaction temperature is 70-100°C, the reaction solvent is DMSO, etc.; the molar ratio of the intermediate (I-1-1-1) to tert-butyl nitrite is 1:1.5-4.

[0055] When the intermediate (I-1) has a structure represented by formula (I-1-2), the intermediate (I-1) is obtained by reacting the intermediate (I-1-2-1) with tert-butyl nitrite:

[0056] When the intermediate (I-1) has a structure represented by formula (I-1-3), the intermediate (I-1) is obtained by reacting the intermediate (I-1-3-1) with polyphosphoric acid:

[0057] Preferably, the reaction conditions of this step are: reaction temperature of 70-100° C., reaction solvent of DMSO or the like; and the molar ratio of the intermediate (I-1-2-1) to tert-butyl nitrite of 1:1.5-4.

[0058] When the intermediate (II-1) has a structure represented by formula (II-1-1), the intermediate (II-1) is obtained by reacting the intermediate (II-1-1-1), phenylacetylene and tert-butyl nitrite:

[0059] Preferably, the reaction conditions of this step are: the reaction temperature is 50-80° C., the reaction solvent is chloroform or the like; sodium acetate is added simultaneously; and the molar ratio of the intermediate (II-1-1-1), phenylacetylene, sodium acetate and tert-butyl nitrite is 1:1-1.5:1-1.5:1.5-4.

[0060] When the intermediate (II-1) has a structure represented by formula (II-1-2), the intermediate (II-1) is obtained by reacting the intermediate (II-1-2-1) with a Grignard reagent corresponding to formula (II-1-2-2) under the action of I:

[0061] Preferably, the reaction conditions of this step are: the reaction solvent is anhydrous THF or the like; the molar ratio of the intermediate (II-1-2-1) to the Grignard reagent corresponding to formula (II-1-2-2) is 1:1 to 2.

[0062] When the intermediate (III-1) has a structure represented by formula (III-1-1), the intermediate (III-1) is obtained by first reacting the intermediate (III-1-1-1) with thionyl chloride and then reacting with aluminum trichloride:

[0063]

[0064]

[0065] Wherein, Z1 is S or O; Z2 is CH or N, X1 is S or Se; R2 is selected from Specifically:

[0066] The compound corresponding to formula (I) is prepared as follows: X is O, R3 is H, and R2 is absent;

[0067]

[0068] Alternatively, the preparation method is as follows: X is N, R3 is H;

[0069]

[0070] The compound corresponding to formula (I) is prepared as follows: X is S, R3 is H, and R2 is absent;

[0071]

[0072] The compound corresponding to formula (I) is prepared as follows: X is Se, R3 is H, and R2 is absent;

[0073]

[0074] The preparation method of the compound corresponding to formula (II) is as follows: R3 is H;

[0075]

[0076] Alternatively, the preparation method of the compound corresponding to formula (II) is as follows:

[0077]

[0078] Alternatively, the preparation method of the compound corresponding to formula (III) is as follows:

[0079]

[0080] The present invention also provides a use of any of the above-mentioned pyridone derivatives in the preparation of anti-influenza A drugs.

[0081] The positive progress effect of the present invention is:

[0082] The hydroxypyridone compounds of the present invention can effectively inhibit the replication of influenza virus in vitro. In particular, the compounds of the present invention are less affected by the influenza PA / I38T mutant strain and show a drug resistance index (RI = IC 50 [I38T] / IC 50 [WT]) is significantly lower than that of positive baloxavir. The present invention also discloses the use of the hydroxypyridone compound in the preparation of a drug for treating baloxavir-resistant viruses, which has low cytotoxicity and high selectivity. The hydroxypyridone compound with a novel structure disclosed in the present invention has promising application prospects in the clinical treatment of baloxavir-resistant virus strains. DETAILED DESCRIPTION

[0083] The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto. Without departing from the above-mentioned technical concept of the present invention, various substitutions and changes can be made according to common technical knowledge and customary means in the field, and all of these should be included within the scope of the present invention.

[0084] Example 1. Synthesis of 1-6-A and 1-6-B

[0085]

[0086] Step 1: Synthesis of compound 1-2

[0087] Under ice bath, potassium carbonate (8.1g, 58.8mmol) was added to a DMF solution (10mL) of compound 1-1 (5.0g, 29.4mmol), and then 3-bromopropyne (3.0mL, 44.2mmol) was added dropwise under stirring. After the addition was complete, the reaction solution was returned to room temperature and heated to 60°C, and the reaction was stirred for 12h. After the reaction was complete, the reaction solution was added to water (100mL) and extracted with ethyl acetate (3×100mL). The organic phases were combined, washed with water (1×100mL) and saturated brine (1×100mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain a crude compound 1-2. Finally, the pure compound 1-2 (5.6g, 92% yield) was obtained by recrystallization from petroleum ether / ethyl acetate. 1 H NMR (500MHz, CDCl3) δ7.72(d,J=8.3Hz,1H),7.07(d,J=1.8Hz,1H),7.04(dd,J=8.4,1 .8Hz,1H),4.80(d,J=2.4Hz,2H),2.61(s,3H),2.59(t,J=2.4Hz,1H).HRMS(ESI):m / z calcd for C 11 H 10 ClO2 + [M+H] + :209.0364,found:209.0360.

[0088] Step 2: Synthesis of Compound 1-3

[0089] In a sealed tube, compound 1-2 (4.16 g, 20 mmol) was dissolved in DMSO (5 mL), and then tert-butyl nitrite (7.1 mL, 60 mmol) was added dropwise with stirring. After the addition was complete, the reaction solution was heated to 80°C and stirred for 4 hours. After the reaction was complete, the reaction solution was added to water (50 mL) and extracted with ethyl acetate (3×50 mL). The organic phases were combined and washed with water (1×100 mL) and saturated brine (1×100 mL), dried over anhydrous sodium sulfate, filtered, and dried. The crude product was purified by silica gel column chromatography to obtain pure compound 1-3 (2.35 g, 50%). 1 H NMR (500MHz, DMSO-d6) δ9.21 (s, 1H), 8.13 (d, J = 8.7Hz, 1H), 7.37 (dd, J = 8.7, 2.1Hz, 1H), 7.30 (d, J = 2.1Hz, 1H), 5.28 (s, 2H). HRMS (ESI): m / z calcd for C 11 H7ClNO3 + [M+H]+ :236.0109,found:236.0101

[0090] Step 3: Synthesis of Compound 1-4

[0091] Under ice bath, compound 1-3 (2.35 g, 10 mmol) was added to 15 mL of methanol, and then sodium borohydride (0.76 g, 20 mmol) was slowly added under stirring. The reaction solution was warmed to room temperature and stirred for 2 h. After completion of the reaction, 5 mL of water was added to quench the reaction, and then the mixture was concentrated under reduced pressure to remove most of the methanol. The aqueous phase was extracted with dichloromethane (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain the crude product of 1-4. Finally, the pure product of compound 1-4 (2.18 g, 92% yield) was obtained by recrystallization from ethyl acetate. 1 H NMR(500MHz,DMSO-d6)δ8.74(d,J=1.2Hz,1H),7.52(dd,J=8.1,0.7Hz,1H),7.26–7.09( m,2H),6.44(d,J=5.4Hz,1H),5.93(d,J=5.3Hz,1H),5.21–5.11(m,2H).HRMS(ESI):m / z calcd for C 11 H7ClNO2 + [M-OH] + :220.0160,found:220.0162

[0092] Step 4: Synthesis of Compound 1-5

[0093] Compound 1-4 (0.28 g, 1.2 mmol) was added to a 50% (w / w)-T4P / EA solution (1 mL, 1.2 mmol) in n-butylphosphoric acid (50% ethyl acetate solution), and the mixture was stirred at room temperature. (R)-7-Benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione (0.20 g, 0.6 mmol) and 2 mL of ethyl acetate were then added. The reaction mixture was heated to 110°C and stirred for 5 hours. After completion of the reaction, the reaction mixture was quenched by adding 15 mL of saturated sodium bicarbonate solution and extracted with ethyl acetate (2 × 50 mL). The organic phases were combined and washed with saturated brine (1×50 mL), dried over anhydrous sodium sulfate, filtered, and dried. The crude product was purified by column chromatography to give 58 mg and 52 mg of pure compounds 1-5-A and 1-5-B, respectively (total yield 17%). The obtained compounds were detected by liquid chromatography, with a retention time of 7.10 min for compound 1-5-A and 7.14 min for compound 1-5-B. Compounds 1-5-A and 1-5-B are two diastereomers of formula (1-5) with respect to *C, the same below.

[0094] Compound 1-5-A: 1 H NMR(500MHz, CDCl3)δ8.28(s,1H),7.67–7.64(m,2H),7.39(dd,J=8.0,6.4Hz,2H),7.37–7.28(m,3H),7.26(s ,1H),6.98(d,J=7.6Hz,1H),6.13(d,J=7.8Hz,1H),5.58(s,1H),5.53–5.46(m,2H),5.38(d,J=10.6Hz,1H),4 .87(dd,J=14.8,1.4Hz,1H),4.65(dd,J=13.6,2.6Hz,1H),4.50(dd,J=9.9,3.0Hz,1H),3.83(dd,J=10.8,3.0 Hz,1H),3.75(dd,J=11.9,3.3Hz,1H),3.33–3.24(m,2H),2.99(ddd,J=13.4,11.8,3.5Hz,1H).HRMS(ESI):m / z calcd for C 28 H 24 ClN4O6 + [M+H] + :547.1379,found:547.1371 Compound 1-5-B: 1H NMR(500MHz, CDCl3)δ8.30(s,1H),7.61–7.56(m,2H),7.38–7.33(m,2H),7.32–7.28(m,1H),7.12(d,J=2.1Hz ,1H),6.96(d,J=7.7Hz,1H),6.78(dd,J=8.1,2.1Hz,1H),6.44(d,J=8.2Hz,1H),5.79(d,J=7.7Hz,1H),5.59(d ,J=11.0Hz,1H),5.48–5.43(m,2H),5.41(d,J=11.0Hz,1H),4.87(dd,J=14.7,1.3Hz,1H),4.79(dd,J=9.9,3.0 Hz,1H),4.70(dd,J=13.3,2.3Hz,1H),3.80(ddd,J=19.6,11.2,3.1Hz,2H),3.34–3.18(m,3H).HRMS(ESI):m / z calcd for C 28 H 24 ClN4O6 + [M+H] + :547.1379,found:547.1380

[0095] Step 5: Synthesis of compound 1-6-A

[0096] Compound 1-5-A (55 mg, 0.1 mmol) was added to 1 mL of N,N-dimethylacetamide, followed by the addition of lithium chloride (42 mg, 1 mmol). The reaction mixture was stirred at 80°C for 6 h. After completion of the reaction, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M aqueous HCl, and 1 mL of water were added, and stirring continued for 1 h. The precipitated solid was collected by filtration and dried to obtain crude compound 1-6-A. Further recrystallization from isopropyl ether / chloroform afforded pure compound 1-6-A (36 mg, 79% yield). It was a white solid, mp 212.4-213.3°C. 1H NMR (500MHz, DMSO-d6) δ8.95(s,1H),7.37(d,J=9.5Hz,1H),7.25(d,J=2.2Hz,1H),7.10(d,J= 8.3Hz,1H),7.05(d,J=7.6Hz,1H),5.92(s,1H),5.66(d,J=7.6Hz,1H),5.49(d,J=14.8Hz,1H), 4.94(d,J=14.8Hz,1H),4.85(d,J=9.8Hz,1H),4.43(d,J=13.4Hz,1H),3.77(dd,J=10.8,3.1H z,1H),3.73(dd,J=11.7,3.3Hz,1H),3.62–3.55(m,1H),3.40-3.42(m,1H),3.16–3.10(m,1H). 13 C NMR(125MHz,DMSO-d6)δ160.93,158.20,157.12,157.06,138.20,135.71,133.67,130.81,125.24, 124.65,123.29,115.81,110.91,70.23,68.07,65.57,64.45,61.82,45.38,22.81.HRMS(ESI):m / z calcd for C 21 H 18 ClN4O6 + [M+H] + :457.0910,found:457.0912

[0097] Step 6: Synthesis of compound 1-6-B

[0098] Compound 1-5-B (55 mg, 0.1 mmol) was added to 1 mL of N,N-dimethylacetamide, followed by the addition of lithium chloride (42 mg, 1 mmol). The reaction mixture was stirred at 80°C for 6 h. After completion of the reaction, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M aqueous HCl, and 1 mL of water were added, and stirring continued for 1 h. The precipitated solid was collected by filtration and dried to obtain crude compound 1-6-B. Further recrystallization from isopropyl ether / chloroform afforded pure compound 1-6-B (30 mg, 66% yield). It was a white solid, mp 204.1-205.0°C. 1H NMR (500MHz, DMSO-d6) δ11.66(s,1H),8.80(s,1H),7.68(d,J=8.2Hz,1H),7.38(d,J=2.1 Hz,1H),7.32(dd,J=8.2,2.2Hz,1H),7.18(d,J=7.6Hz,1H),5.84(s,1H),5.76(d,J=7.7Hz ,1H),5.55(d,J=14.9Hz,1H),4.91(d,J=14.9Hz,1H),4.53–4.45(m,1H),4.42(d,J=13.4 Hz,1H),3.68(td,J=10.5,3.2Hz,2H),3.63–3.55(m,1H),3.39(s,1H),3.15–3.09(m,1H). 13 C NMR(125MHz,DMSO-d6)δ160.87,158.39,156.34,155.62,138.55,135.71,133.40,126.79,125.20,124.02,1 16.14,111.10,79.26,79.00,78.74,70.27,68.06,65.54,64.73,61.97,45.37,22.79.HRMS(ESI):m / zcalcd for C 21 H 18 ClN4O6 + [M+H] + :457.0910,found:457.0910

[0099] Example 2. Synthesis of 2-6-A and 2-6-B

[0100] Following the procedure of Example 1, except that 4'-chloro-2'-hydroxyacetophenone (1-1) was replaced with 4-fluoro-2-hydroxyacetophenone, two diastereomers of compound 2-6 were obtained: compound 2-6-A and compound 2-6-B. Compound 2-6-A: white solid, mp 226.9-227.3°C. 11H NMR (500 MHz, DMSO-d6) δ 8.95 (s, 1H), 7.45–7.29 (m, 1H), 7.05 (d, J = 3.1 Hz, 1H), 7.03–7.01 (m, 1H), 6.86 (m, 1H), 5.89 (m, 1H), 5.64 (m, 1H), 5.51 (d, J = 15.0 Hz, 1H), 4.93 (d, J = 14.8 Hz, 1H), 4.84 (m, 1H), 4.44 (d, J = 13.4 Hz, 1H), 3.75 (ddd, J = 22.0, 11.3, 3.3 Hz, 3H), 3.63–3.55 (m, 1H), 3.15 (d, J = 12.5 Hz, 1H). 13 13C NMR (125 MHz, DMSO-d6) δ 164.68, 162.71, 160.91 (d, J = 11.8 Hz), 158.84, 157.35, 157.06, 138.19, 133.91 (d, J = 10.58 Hz), 122.45, 115.77, 111.42 (d, J = 21.50 Hz), 110.87 (d, J = 22.68 Hz), 110.58, 110.40, 68.12, 67.31, 65.62, 64.28, 61.72, 45.37, 22.81. HRMS (ESI): m / z calcd for C 21 H 18 FN4O6 + [M + H] + : 441.1205, found: 441.1206 Compound 2-6-B: White solid, mp 232.5 - 233.6 °C. 1 1H NMR (500 MHz, DMSO-d6) δ 11.67 (s, 1H), 8.81 (s, 1H), 7.71 (dd, J = 8.5, 6.6 Hz, 1H), 7.17 (dd, J = 10.8, 7.5 Hz, 2H), 7.11 (td, J = 8.4, 2.7 Hz, 1H), 5.84 (s, 1H), 5.77 (d, J = 7.6 Hz, 1H), 5.55 (d, J = 14.8 Hz, 1H), 4.91 (d, J = 14.9 Hz, 1H), 4.49 (dd, J = 9.9, 3.2 Hz, 1H), 4.42 (d, J = 13.3 Hz, 1H), 3.67 (dt, J = 10.9, 5.5 Hz, 2H), 3.61–3.56 (m, 1H), 3.40 (d, J = 2.8 Hz, 1H), 3.15–3.08 (m, 1H). 13C NMR (125MHz, DMSO-d6) δ171.31,160.88,159.11(d,J=11.8Hz),156.33,155.85,152.81,138.57,133.63(d,J=10.58Hz),116.13, 115.86,112.13(d,J=21.50Hz),111.40(d,J=22.68Hz),111.11,70.19,68.06,65.53,64.58,61.99,45.39,22.80.HRMS(ESI):m / z calcd for C 21 H 18 FN4O6 + [M+H] + :441.1205,found:441.1206

[0101] Example 3. Synthesis of 3-6-A and 3-6-B

[0102] Referring to the method of Example 1, except that 4'-chloro-2'-hydroxyacetophenone (1-1) was replaced with 2'-hydroxyacetophenone, two diastereomers corresponding to compound 3-6 were finally obtained: compound 3-6-A and compound 3-6-B.

[0103] Compound 3-6-A: white solid, mp 228.3-229.5℃. 1 H NMR (500MHz, DMSO-d6) δ8.90(s,1H),7.40(t,J=7.7Hz,1H),7.31(d,J=7.5Hz,1H),7.15(d,J=7.9Hz,1 H),7.08(d,J=7.7Hz,1H),7.02(t,J=7.3Hz,1H),5.84(s,1H),5.65(d,J=7.6Hz,1H),5.46(d,J=14.9H z,1H),4.93(dd,J=10.0,3.2Hz,1H),4.87–4.81(m,1H),4.43(dd,J=13.4,2.6Hz,1H),3.75(ddd,J=17 .9,11.2,3.2Hz,2H),3.60(d,J=10.4Hz,1H),3.42–3.39(m,1H),3.16(ddd,J=15.0,11.9,3.5Hz,1H). 1313C NMR (125 MHz, DMSO-d6) δ 170.88, 160.87, 157.50, 157.35, 156.72, 152.55, 138.25, 132.28, 126.47, 124.91, 123.12, 116.29, 116.08, 110.89, 73.13, 70.26, 68.10, 65.56, 64.49, 62.61, 45.42. HRMS (ESI): m / z calcd for C 21 H 19 N4O6 + [M + H] + : 423.1300, found: 423.1304

[0104] Compound 3-6-B: White solid, mp 215.1 - 216.1 °C. 1 1H NMR (500 MHz, Methanol-d4) δ 8.61 (s, 1H), 7.43 (td, J = 7.7, 1.7 Hz, 1H), 7.36 (d, J = 7.5 Hz, 1H), 7.19 (d, J = 8.0 Hz, 1H), 7.16 (dd, J = 7.6, 1.7 Hz, 1H), 7.06 (t, J = 7.4 Hz, 1H), 5.93 (d, J = 7.5 Hz, 1H), 5.76 (s, 1H), 5.48 (d, J = 14.9 Hz, 1H), 5.13 (dd, J = 10.0, 3.1 Hz, 1H), 4.61 (dd, J = 13.5, 2.5 Hz, 1H), 3.85 (ddd, J = 22.6, 11.3, 3.3 Hz, 2H), 3.56 (t, J = 10.5 Hz, 1H), 3.51–3.46 (m, 1H), 3.46–3.33 (m, 1H), 3.32 (d, J = 2.0 Hz, 1H). 13 13C NMR (125 MHz, Methanol-d4) δ 162.06, 159.39, 158.52, 157.32, 154.04, 140.64, 133.86, 133.13, 128.32, 126.82, 124.75, 118.26, 112.64, 91.46, 72.20, 69.94, 67.39, 66.38, 65.31, 49.51, 47.09. HRMS (ESI): m / z calcd for C 21 H 19 N4O6 + [M + H] + : 423.1300, found: 423.1298

[0105] Example 4. Synthesis of 4-9-A and 4-9-B

[0106]

[0107] Step 1: Synthesis of compound 4-2

[0108] To a solution of compound 4-1 (5.0 g, 37.0 mmol) in ethanol (15 mL) at room temperature, di-tert-butyl dicarbonate (9.3 mL, 40.7 mmol) was added. After the addition was complete, the reaction mixture was heated to 65°C and stirred for 24 hours. After completion of the reaction, the reaction mixture was spin-dried to obtain crude compound 4-2 (7.4 g, 85% yield), which was used directly in the next reaction. 1 H NMR(500MHz, CDCl3) δ10.93(s,1H),8.46(dd,J=8.6,1.2Hz,1H),7.85(dd,J=8.0,1.6Hz,1H),7 .54–7.46(m,1H),7.02(ddd,J=8.2,7.2,1.2Hz,1H),2.64(s,3H),1.52(s,9H).HRMS(ESI):m / z calcdfor C 13 H 17 NaNO3 + [M+Na] + :258.1101,found:258.1109

[0109] Step 2: Synthesis of compound 4-3

[0110] Under ice bath, NaH (1.44 g, 60 mmol) was added in batches to 30 mL of anhydrous THF solution of compound 4-2 (7.05 g, 30 mmol) under N2 protection, then returned to room temperature and stirred for 1 h. 3-Bromopropyne (3.9 mL, 45 mmol) was added dropwise to the reaction solution and refluxed overnight. After completion of the reaction, 10 mL of saturated NH4Cl solution was added to quench the reaction, and then most of the THF was removed by concentration under reduced pressure. The aqueous phase was extracted with ethyl acetate (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain the crude product of 4-3. The obtained crude product was purified by silica gel column chromatography to obtain pure 4-3 (5.0 g, yield 61%). 1 H NMR (500MHz, CDCl3) δ7.64 (s, 1H), 7.52–7.33 (m, 3H), 4.77–4.10 (m, 2H), 2.52 (s, 3H), 2.24 (s, 1H), 1.41 (d, J = 95.1Hz, 9H). HRMS (ESI): m / z calcd forC 16H 19 NaNO3 + [M+Na] + :296.1258,found:296.1257

[0111] Step 3: Synthesis of compound 4-4

[0112] In a sealed tube, compound 4-3 (4.1 g, 15 mmol) was dissolved in DMSO (5 mL), and tert-butyl nitrite (5.3 mL, 45 mmol) was then added dropwise with stirring. The reaction mixture was heated to 80°C and stirred for 4 h. After the reaction was complete, the reaction mixture was added to water (50 mL) and extracted with ethyl acetate (3 × 50 mL). The combined organic phases were washed with saturated brine (1 × 100 mL), dried over anhydrous sodium sulfate, filtered, and dried. The resulting crude product was purified by silica gel column chromatography to obtain pure compound 4-4 (1.9 g, 42% yield). 1 H NMR (500MHz, CDCl3) δ8.56 (s, 1H), 8.14 (s, 1H), 7.61 (t, J = 7.4Hz, 1H), 7.50–7.28 (m, 2H), 5.70–3.89 (m, 2H), 1.31 (s, 9H). HRMS (ESI): m / z calcdfor C 16 H 16 NaN2O4 + [M+Na] + :323.1003,found:323.1002

[0113] Step 4: Synthesis of compound 4-5

[0114] Compound 4-4 (1.5 g, 5 mmol) was dissolved in 10 mL of anhydrous DCM at room temperature, and then 5 mL of trifluoroacetic acid was added dropwise with stirring. The reaction solution was stirred at room temperature for 6 h. After completion of the reaction, the reaction solution was spin-dried, and the residue was dissolved in 20 mL of DCM. Saturated sodium bicarbonate solution was added to adjust the pH to 7. The aqueous phase was extracted with DCM (3 × 20 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried. The resulting crude product was recrystallized from petroleum ether / dichloromethane to obtain pure compound 4-5 (0.76 g, 76% yield). 1H NMR(500MHz,DMSO-d6)δ9.03(s,1H),7.99(dd,J=8.3,1.7Hz,1H),7.35(ddd,J=8.4,5.2,1.7Hz,2H),6.9 1(dd,J=8.5,1.1Hz,1H),6.78(ddd,J=8.2,6.8,1.1Hz,1H),4.23(d,J=3.8Hz,2H).HRMS(ESI):m / zcalcd for C 11 H9N2O2 + [M+H] + :201.0659,found:201.0653

[0115] Step 5: Synthesis of Compound 4-6

[0116] At room temperature, compound 4-5 (0.76 g, 3.8 mmol) and DIPEA (0.7 mL, 4 mmol) were dissolved in 5 mL of anhydrous DCM, and then acetyl chloride (0.32 mL, 4.5 mmol) was added dropwise with stirring. After the addition was complete, the reaction solution was stirred at room temperature for 2 h. After the reaction was complete, 20 mL of DCM was added to dilute the reaction solution, and then washed with dilute hydrochloric acid (0.5 M, 1 × 20 mL), saturated sodium bicarbonate (1 × 20 mL), and saturated sodium chloride solution (1 × 20 mL), respectively. The combined organic phases were dried over anhydrous sodium sulfate, filtered, and spin-dried. The resulting crude product was then slurried with diethyl ether to obtain pure compound 4-6 (0.8 g, yield 87%). 1 H NMR (500MHz, CDCl3) δ8.65–8.53(m,1H),8.16(dd,J=7.8,1.7Hz,1H),7.70(dd,J=7.7,1.7Hz,1H),7.59(dd,J=7.7,1.2 Hz,1H),7.35(dd,J=7.9,1.2Hz,1H),5.86(d,J=15.7Hz,1H),4.04(dd,J=15.7,1.5Hz,1H),1.86(s,3H).HRMS(ESI):m / z calcd for C 13 H 11 N2O3 + [M+H] + :243.0795,found:243.0794

[0117] Step 6: Synthesis of Compound 4-7

[0118] Under ice bath, compound 4-6 (0.8 g, 3.3 mmol) was added to 10 mL of methanol, and then sodium borohydride (0.25 g, 6.6 mmol) was slowly added under stirring. The reaction solution was warmed to room temperature and stirred for 2 h. After completion of the reaction, 5 mL of water was added to quench the reaction, and then the mixture was concentrated under reduced pressure to remove most of the methanol. The aqueous phase was extracted with dichloromethane (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain crude 4-7. Finally, pure compound 4-7 (0.72 g, 90% yield) was obtained by recrystallization from ethyl acetate. 1 H NMR (500MHz, DMSO-d6) δ8.72(d,J=1.1Hz,1H),7.58(dd,J=7.5,1.6Hz,1H),7.51–7.39(m,3H),6.17(d,J=141. 5Hz,1H),5.80(dd,J=16.4,1.2Hz,1H),5.72(s,1H),3.81(dd,J=16.4,1.5Hz,1H),1.76(s,3H).HRMS(ESI):m / z calcd for C 13 H 13 N2O3 + [M+H] + :245.0921,found:245.0918

[0119] Step 7: Synthesis of compounds 4-8-A and 4-8-B

[0120] In a sealed tube, compound 4-7 (0.29 g, 1.2 mmol) was added to a 50% (w / w)-T4P / EA solution (1 mL, 1.2 mmol), and the mixture was stirred at room temperature. (R)-7-Benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione (0.20 g, 0.6 mmol) and 2 mL of ethyl acetate were then added. The reaction mixture was heated to 110°C and stirred for 5 h. After completion of the reaction, the reaction mixture was quenched by adding 15 mL of saturated sodium bicarbonate solution and extracted with ethyl acetate (2 × 50 mL). The combined organic phases were washed with saturated brine (1×50 mL), dried over anhydrous sodium sulfate, filtered, and dried by rotary evaporation. The resulting crude product was purified by column chromatography to yield 46 mg and 40 mg of pure compounds 4-8-A and 4-8-B, respectively (total yield 13%). The resulting compounds were detected by liquid chromatography, with a retention time of 7.60 min for compound 4-8-A and 7.70 min for compound 4-8-B. Compounds 4-8-A and 4-8-B are two diastereomers corresponding to compound 4-8 of the above formula.

[0121] Compound 4-8-A: 1 H NMR(500MHz,DMSO-d6)δ9.22(s,1H),8.04(dd,J=7.8,1.7Hz,1H),7.80(td,J=7.6,1.7Hz,1H),7.70(d,J=7.6Hz,1H),7.65–7.60(m,2H),7.58–7.54(m,2H),7.39(m,1H),7.26(m,2H),6.22(d,J=7.6Hz,1H),5.84(s,1H),5.61(m,1H),5.07(d,J=2.4Hz,2H),4.80(ddd,J=12.6,9.9,4.6Hz,1H),4.18–4.10(m,2H),4.03(td,J=11.3,4.4Hz,2H),3.43(td,J=12.0,3.1Hz,1H),3.13(dd,J=11.4,10.0Hz,1H),2.95(ddd,J=13.7,12.1,4.3Hz,1H),1.77(s,3H).HRMS(ESI):m / z calcd for C 30 H 28 N5O6 + [M+H] + :554.2035,found:554.2038

[0122] Compound 4-8-B: 1 H NMR(500MHz,DMSO-d6)δ8.72(d,J=1.1Hz,1H),7.70(d,J=7.6Hz,1H),7.57(td,J=7.8,1.4Hz,3H),7.53–7.39(m,2H),7.38–7.34(m,2H),7.32–7.28(m,2H),6.22(d,J=7.6Hz,1H),5.80(s,1H),5.68(m,1H),5.08(d,J=2.3Hz,2H),4.83–4.77(m,1H),4.15(dd,J=13.8,2.9Hz,1H),4.02(dt,J=11.2,5.4Hz,2H),3.81(dd,J=16.4,1.5Hz,1H),3.46–3.41(m,1H),3.13(dd,J=11.4,9.9Hz,1H),2.95(ddd,J=13.8,12.2,4.3Hz,1H),1.76(s,3H).HRMS(ESI):m / z calcd for C 30 H 28N5O6 + [M+H] + :554.2035,found:554.2040

[0123] Step 8: Synthesis of compound 4-9-A

[0124] Compound 4-8-A (46 mg, 0.08 mmol) was added to 1 mL of N,N-dimethylacetamide, followed by the addition of lithium chloride (34 mg, 0.8 mmol). The reaction mixture was stirred at 80°C for 6 h. After completion of the reaction, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M aqueous HCl, and 1 mL of water were added, and stirring continued for 1 h. The precipitated solid was collected by filtration and dried to obtain crude compound 4-9-A. Further recrystallization from isopropyl ether / chloroform afforded pure compound 4-9-A (31 mg, 83% yield). It was a white solid, mp 236.0-237.0°C. 1 H NMR(500MHz, DMSO-d6)δ9.21(s,1H),8.04(dd,J=7.8,1.6Hz,1H),7.80(td,J=7.6,1.6Hz,1H),7.64–7.32(m,3H),6.07(d,J=7.4Hz,1H),5.75(s, 2H),4.88(td,J=13.2,11.7,4.1Hz,1H),4.20–3.95(m,3H),3.5-3.75(m ,1H),3.22(t,J=10.8Hz,2H),3.02(td,J=13.1,4.1Hz,1H),1.77(s,3H). 13 C NMR (125MHz, DMSO-d6) δ182.20,170.72,168.72,162.38,158.63,158.52,151.61,141.43,137.80,135.30,134. 69,131.27,129.65,129.03,118.76,118.29,111.82,65.54,65.49,64.78,64.13,54.95,22.16.HRMS(ESI):m / z calcd for C 23 H 22 N5O6 + [M+H] + :464.1565,found:464.1569

[0125] Step 9: Synthesis of compound 4-9-B

[0126] Compound 4-8-B (40 mg, 0.07 mmol) was added to 1 mL of N,N-dimethylacetamide, followed by the addition of lithium chloride (30 mg, 0.7 mmol). The reaction mixture was stirred at 80°C for 6 h. After completion of the reaction, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M aqueous HCl, and 1 mL of water were added, and stirring continued for 1 h. The precipitated solid was collected by filtration and dried to obtain crude compound 4-9-B. Further recrystallization from isopropyl ether / chloroform afforded pure compound 4-9-B (27 mg, 82% yield). It was a white solid, mp 230.6-231.2°C. 1 H NMR(500MHz,DMSO-d6)δ8.70(d,J=18.0Hz,1H),7.57(dd,J=7.4,1.5Hz,1H),7.50(td,J=7.5,1 .6Hz,1H),7.43(dtd,J=17.9,7.5,1.5Hz,2H),7.39–7.20(m,1H),6.01(d,J=15.5Hz,1H),5.80 (d,J=16.7Hz,1H),5.74(d,J=19.2Hz,1H),4.82(s,1H),4.12–3.98(m,3H),3.81(d,J=16.4Hz, 1H),3.47–3.42(m,1H),3.21(t,J=10.7Hz,1H),2.97(t,J=12.8Hz,1H),1.77(d,J=8.4Hz,3H). 13 CNMR(125MHz,DMSO-d6)δ169.56,168.79,162.25,161.17,160.56,155.86,141.46,138.41,130.21,130.09,129 .86,129.01,128.82,128.53,125.09,115.37,66.65,65.64,65.50,65.13,64.72,38.34,22.46.HRMS(ESI):m / z calcd for C 23 H 22 N5O6 + [M+H] + :464.1565,found:464.1570

[0127] Example 5

[0128]

[0129] Step 1: The synthesis of compounds 5-1 to 5-5 is the same as in Example 4

[0130] Step 2: Synthesis of compound 5-6

[0131] At room temperature, compound 5-5 (1.0 g, 5 mmol) and DIPEA (1.1 mL, 6 mmol) were dissolved in 5 mL of anhydrous DCM. Chloroacetyl chloride (0.48 mL, 6 mmol) was then added dropwise with stirring. The reaction mixture was stirred at room temperature for 2 h. After completion of the reaction, 20 mL of DCM was added to dilute the reaction mixture, which was then washed with dilute hydrochloric acid (0.5 M, 1 × 20 mL), saturated sodium bicarbonate (1 × 20 mL), and saturated sodium chloride solution (1 × 20 mL). The combined organic phases were dried over anhydrous sodium sulfate, filtered, and spin-dried. The resulting crude product was then slurried with diethyl ether to obtain pure compound 5-6 (1.3 g, 93% yield). 1 H NMR (500MHz, CDCl3) δ8.62(d,J=1.4Hz,1H),8.20(dd,J=7.9,1.7Hz,1H),7.75(td,J=7.6,1.7Hz,1H),7.64(td,J=7.6,1.2Hz,1H),7.46(dd,J =7.8,1.2Hz,1H),5.83(d,J=15.7Hz,1H),4.12(dd,J=15.7,1.5Hz,1H),3.87(d,J=12.8Hz,1H),3.78(d,J=12.8Hz,1H).HRMS(ESI):m / zcalcd for C 13 H 10 N2ClO3 + [M+H] + :277.0375,found:277.0368

[0132] Step 3: Synthesis of Compound 5-7

[0133] Compound 5-6 (1.1 g, 4 mmol) was dissolved in 5 mL of acetonitrile at room temperature, and KSCN (1.2 g, 12 mmol) was added with stirring. The reaction mixture was stirred at 60°C for 4 h. After completion of the reaction, the solvent was dried and dissolved in 20 mL of ethyl acetate. The organic phase was washed with water (1 × 50 mL) and saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and dried to obtain the crude product. Finally, the product was slurried with diethyl ether to obtain the pure product of compound 5-7 (1.0 g, yield 88%). 1H NMR (500MHz, DMSO-d6) δ9.23(s,1H),8.11(dd,J=7.9,1.7Hz,1H),7.80(td,J=7.6,1.7Hz,1H),7.72(dd,J=8.0,1.3Hz,1H),7.66(td,J =7.6,1.3Hz,1H),5.60(d,J=15.7Hz,1H),4.42(d,J=15.1Hz,1H),4.24(dd,J=15.7,1.5Hz,1H),3.85(d,J=15.1Hz,1H).HRMS(ESI):m / z calcd forC 14 H 10 N3SO3 + [M+H] + :300.0438,found:300.0430

[0134] Step 4: Synthesis of compounds 5-8 to 5-10-A and 5-10-B is the same as in Example 4

[0135] Compound 5-10-A: white solid, mp 239.0-240.0℃. 1 H NMR(500MHz,DMSO-d6)δ9.23(s,1H),8.11(dd,J=7.8,1.5Hz,1H),7.80(t,J=7.5Hz,1H),7.72(d, J=7.8Hz,1H),7.65–7.61(m,1H),7.33(d,J=12.5Hz,1H),6.07(d,J=7.4Hz,1H),5.88–5.48(m,2H) ,4.89(ddd,J=13.5,10.1,4.0Hz,1H),4.41(d,J=15.1Hz,1H),4.24(d,J=15.4Hz,1H),4.17–3.99 (m,4H),3.84(d,J=15.0Hz,1H),3.46(d,J=2.9Hz,1H),3.22(s,1H),3.01(dd,J=13.2,4.2Hz,1H). 13C NMR(125MHz,DMSO-d6)δ181.42,169.65,165.44,162.25,158.99,158.78,151.38,139.79,138.35,135.75,134.69, 132.11,129.92,129.56,119.47,117.98,113.35,112.47,65.72,65.68,64.91,64.56,40.56,37.92.HRMS(ESI):m / z calcd for C 24 H 21 N6O6S + [M+H] + :521.1238,found:521.1240

[0136] Compound 5-10-B: white solid, mp 245.1-246.0℃. 1 H NMR(500MHz,DMSO-d6)δ8.69(s,1H),7.66–7.60(m,2H),7.50(dd,J=6.9,2.1Hz,1H),7.43(ddd,J =7.0,4.8,1.9Hz,2H),7.41–7.32(m,1H),6.12(s,1H),6.07(d,J=7.4Hz,1H),4.89(td,J=15.7,14 .5,8.5Hz,2H),4.48(d,J=16.8Hz,1H),4.09(dd,J=14.1,2.9Hz,1H),4.03(td,J=11.7,5.5Hz,2H) ,3.47(dd,J=12.2,2.9Hz,1H),3.28(s,2H),3.23(t,J=10.7Hz,1H),3.02(td,J=13.1,4.1Hz,1H). 13 C NMR(125MHz,DMSO-d6)δ170.62,167.50,162.35,161.22,155.61,151.56,141.62,137.73,136.71,129.42,128.98, 128.77,126.45,125.17,118.22,114.04,111.73,103.00,65.74,65.50,65.44,64.74,42.84,40.81.HRMS(ESI):m / z calcd for C 24 H 21 N6O6S + [M+H] +:521.1238,found:521.1234

[0137] Example 6. Synthesis of 6-6-A and 6-6-B

[0138]

[0139] Step 1: Synthesis of compound 6-2

[0140] Compound 6-1 (5.9 g, 30 mmol) was dissolved in 20 mL of acetone at room temperature, and dimethyl sulfide (3.3 mL, 45 mmol) was added. The reaction mixture was stirred at room temperature overnight. After the reaction, the reaction mixture was filtered to obtain a white solid, which was dried to obtain crude compound 6-2 (7.0 g, 90% yield), which was used directly in the next step.

[0141] Step 2: Synthesis of compound 6-3

[0142] In a sealed tube, compound 6-2 (5.2 g, 20 mmol) was added to 10 mL of chloroform. Sodium acetate (1.64 g, 20 mmol), phenylacetylene (2.2 mL, 20 mmol), and tert-butyl nitrite (7.1 mL, 60 mmol) were added sequentially. The reaction solution was heated to 60°C and stirred for 6 h. After the reaction, most of the solvent was removed by rotary evaporation, and the residue was dissolved in 20 mL of DCM. The combined organic phases were washed sequentially with water (1 × 50 mL) and saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and dried to dryness to obtain the crude product. Pure compound 6-3 (3.3 g, 66% yield) was obtained by silica gel column chromatography. 1 H NMR (500MHz, CDCl3) δ8.38–8.33(m,2H),7.88–7.83(m,2H),7.70–7.65(m,1H),7.57–7.49(m,5H),7.06(s,1H).HRMS(ESI):m / z calcd for C 16 H 11 NaNO2 + [M+Na] + :272.0682,found:272.0683

[0143] Step 3: Synthesis of compound 6-4

[0144] Under ice bath, compound 6-3 (2.5 g, 10 mmol) was added to 10 mL of methanol, and then sodium borohydride (0.76 g, 20 mmol) was slowly added under stirring. The reaction solution was warmed to room temperature and continued to stir for 2 h. After the reaction was completed, 5 mL of water was added to quench the reaction, and then the mixture was concentrated under reduced pressure to remove most of the methanol. The aqueous phase was extracted with dichloromethane (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain crude 6-4. Finally, pure compound 6-4 (2.2 g, 90% yield) was obtained by recrystallization from petroleum ether / ethyl acetate. 1 H NMR(500MHz, CDCl3)δ7.75–7.69(m,2H),7.52–7.48(m,2H),7.45–7.37(m,5H),7.36–7 .31(m,1H),6.42(s,1H),6.03(d,J=2.1Hz,1H),3.02(d,J=3.3Hz,1H).HRMS(ESI):m / z calcd for C 16 H 12 NO + [M-OH] + :234.0914,found:234.0918

[0145] Step 4: Synthesis of compounds 6-5-A and 6-5-B

[0146] In a sealed tube, compound 6-4 (0.3 g, 1.2 mmol) was added to a 50% (w / w)-T4P / EA solution (1 mL, 1.2 mmol), and the mixture was stirred at room temperature. (R)-7-Benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione (0.20 g, 0.6 mmol) and 2 mL of ethyl acetate were then added. The reaction mixture was heated to 110°C and stirred for 5 h. After completion of the reaction, the reaction mixture was quenched by adding 15 mL of saturated sodium bicarbonate solution and extracted with ethyl acetate (2 × 50 mL). The combined organic phases were washed with saturated brine (1×50 mL), dried over anhydrous sodium sulfate, filtered, and dried in spun-dry form. The resulting crude product was purified by column chromatography to yield 30 mg and 24 mg of pure compounds 6-5-A and 6-5-B, respectively (total yield 8%). The resulting compounds were analyzed by liquid chromatography, with a retention time of 7.0 min for compound 6-5-A and 7.1 min for compound 6-5-B.

[0147] Compound 6-5-A: 11H NMR (500 MHz, Methanol-d4) δ 7.81–7.77 (m, 2H), 7.72 (d, J = 7.6 Hz, 1H), 7.51 (ddd, J = 7.7, 4.1, 1.9 Hz, 3H), 7.49–7.44 (m, 4H), 7.37 (dd, J = 8.4, 6.9 Hz, 2H), 7.31 (dq, J = 9.5, 7.3, 6.7 Hz, 4H), 6.70 (s, 1H), 6.46 (d, J = 7.5 Hz, 1H), 5.91 (s, 1H), 5.16 (d, J = 2.1 Hz, 2H), 4.64 (dd, J = 9.9, 4.7 Hz, 1H), 4.19 (dd, J = 14.0, 3.0 Hz, 1H), 4.05 (td, J = 12.1, 4.5 Hz, 2H), 3.52 (td, J = 11.9, 3.1 Hz, 1H), 3.17 (dd, J = 11.5, 9.9 Hz, 1H), 2.98 (ddd, J = 14.0, 12.2, 4.4 Hz, 1H). HRMS (ESI): m / z calcd for C 33 H 29 N4O5 + [M + H] + : 561.2133, found: 561.2128

[0148] Compound 6-5-B: 1 1H NMR (500 MHz, DMSO-d6) δ 8.23–8.17 (m, 2H), 8.03–7.98 (m, 2H), 7.79–7.75 (m, 1H), 7.70 (d, J = 7.6 Hz, 1H), 7.65–7.58 (m, 4H), 7.57–7.54 (m, 3H), 7.36 (dd, J = 8.1, 6.5 Hz, 2H), 7.32–7.28 (m, 2H), 6.22 (d, J = 7.6 Hz, 1H), 5.75 (s, 1H), 5.08 (d, J = 2.4 Hz, 2H), 4.82–4.77 (m, 1H), 4.15 (dd, J = 13.8, 2.8 Hz, 1H), 4.03 (dt, J = 11.3, 5.8 Hz, 2H), 3.47–3.41 (m, 1H), 3.13 (dd, J = 11.4, 10.0 Hz, 1H), 2.99–2.92 (m, 1H). HRMS (ESI): m / z calcd for C 33 H 29 N4O5 + [M + H] + : 561.2133, found: 561.2130

[0149] Step 5: Synthesis of compound 6-6-A

[0150] Compound 6-5-A (30 mg, 0.053 mmol) was added to 1 mL of N, N-dimethylacetamide, lithium chloride (26 mg, 0.6 mmol) was added, and the reaction solution was stirred at 80 ° C for 6 hours. After the reaction was completed, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M HCl aqueous solution and 1 mL of water were added, and stirring was continued for 1 hour. The solid precipitated in the reaction solution was collected by suction filtration and dried to obtain a crude product. Further recrystallization from isopropyl ether / chloroform gave pure compound 6-6 (17 mg, yield 68%). White solid, mp 198.0-199.0 ° C 1 H NMR(500MHz,DMSO-d6)δ7.87–7.84(m,2H),7.62(d,J=7.5Hz,1H),7.51–7.46(m ,5H),7.36(q,J=6.9,6.2Hz,3H),7.28(t,J=7.3Hz,1H),6.98(s,1H),6.07(d,J= 7.4Hz,1H),5.85(s,1H),4.93–4.84(m,1H),4.09(dd,J=14.1,3.0Hz,1H),4.03 (td,J=11.7,5.5Hz,2H),3.46(d,J=2.9Hz,1H),3.23(s,1H),3.05–2.99(m,1H). 13 C NMR (125MHz, DMSO-d6) δ169.40,168.56,162.68,162.45,151.96,142.57,138.35,131.00,129.80,128. 92,128.15,127.16,126.60,126.00,118.85,112.51,98.96,67.95,65.88,65.83,65.11.HRMS(ESI):m / z calcd for C 26 H 23 N4O5 + [M+H] + :471.1663,found:471.1666

[0151] Step 6: Synthesis of compound 6-6-B

[0152] Compound 6-5-B (24 mg, 0.043 mmol) was added to 1 mL of N,N-dimethylacetamide, followed by the addition of lithium chloride (26 mg, 0.6 mmol). The reaction mixture was stirred at 80°C for 6 h. After completion of the reaction, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of a 0.5 M aqueous solution of HCl, and 1 mL of water were added, and stirring continued for 1 h. The precipitated solid was collected by filtration and dried to obtain the crude product. Further recrystallization from isopropyl ether / chloroform afforded pure compound 6-6-B (13 mg, 64% yield). It was a white solid, mp 202.5-203.1°C. 1 H NMR(500MHz,DMSO-d6)δ8.20(d,J=7.6Hz,2H),8.02(dd,J=7.3,2.1Hz,1H),7.78(t,J=7.4Hz,1 H),7.73(dd,J=7.6,1.6Hz,1H),7.66–7.61(m,4H),7.60–7.56(m,1H),7.50(s,1H),7.35(d,J= 12.3Hz,1H),6.07(d,J=7.4Hz,1H),5.75(s,1H),4.92–4.85(m,1H),4.08(td,J=13.3,12.7,4. 9Hz, 2H), 4.03–4.00 (m, 1H), 3.45 (d, J = 2.9Hz, 1H), 3.24 (d, J = 10.7Hz, 1H), 3.04–2.98 (m, 1H). 13 C NMR(125MHz,DMSO-d6)δ185.40,170.62,167.14,162.34,161.89,151.56,151.08,137.72,135.28,134.49,132.49,131.12,1 31.01,130.25,130.08,128.89,128.07,124.84,118.21,111.72,104.92,99.76,65.50,65.44,64.74,54.91.HRMS(ESI):m / z calcd for C 26 H 23 N4O5 + [M+H] + :471.1663,found:471.1658

[0153] Example 7. Synthesis of 7-6-A and 7-6-B

[0154] The method of Example 6 was followed, except that 2-bromoacetophenone (6-1) was replaced by α-bromo-4-chloroacetophenone. The total yield was 9%.

[0155] Compound 7-6-A: white solid, mp 186.2-187.2℃. 1 H NMR (500MHz, DMSO-d6) δ8.23(m,2H),8.00(dd,J=7.6,1.8Hz,3H),7.70(d,J=8.6Hz,3H),7.58(m,2H),7.35(d,J=12.4Hz,1H),6. 07(d,J=7.4Hz,1H),5.75(s,1H),4.93–4.82(m,1H),4.11–4.01(m,3H),3.48(m,1H),3.24(d,J=10.7Hz,1H),3.04–2.99(m,1H). 13 C NMR (125MHz, DMSO-d6) δ185.69,170.46,169.44,164.53,162.54,162.32,162.27,151.52,137.79,135.39,134.47,130.28,1 28.89,128.63,128.56,122.90,118.38,116.69,116.51,111.82,100.96,65.52,65.46,64.75,54.93,48.63.HRMS(ESI):m / z calcd for C 26 H 22 ClN4O5 + [M+H] + :505.1274,found:505.1272

[0156] Compound 7-6-B: white solid, mp 191.4-192.0℃. 1 H NMR(500MHz,DMSO-d6)δ7.86–7.84(m,2H),7.62(d,J=7.5Hz,1H),7.53–7.47(m,5H ),7.42(d,J=1.9Hz,1H),7.35(d,J=12.5Hz,1H),6.98(s,1H),6.07(d,J=7.4Hz,1H) ,5.87(s,1H),4.93–4.83(m,1H),4.09(dd,J=14.0,3.0Hz,1H),4.03(td,J=11.7,5 .6Hz,2H),3.48–3.43(m,1H),3.24(d,J=10.7Hz,1H),3.02(td,J=13.1,4.2Hz,1H). 13C NMR (125MHz, DMSO-d6) δ184.59,170.83,170.55,162.43,162.18,151.66,139.56,137.88,134.13,132.23,131.27,131.22, 129.53,129.13,128.87,126.14,126.05,118.37,111.93,101.05,65.59,65.54,64.83,64.18,63.73,54.98.HRMS(ESI):m / z calcd for C 26 H 22 ClN4O5 + [M+H] + :505.1274,found:505.1278

[0157] Example 8. Synthesis of 8-8

[0158]

[0159] Step 1: Synthesis of compound 8-2

[0160] Compound 8-1 (3.5 g, 24.5 mmol) was dissolved in a mixture of 10 mL of anhydrous DCM and 100 μL of anhydrous DMF. Oxalyl chloride (4.2 mL, 49 mmol) was slowly added dropwise. The reaction mixture was stirred at room temperature overnight. After the reaction, the reaction mixture was dried to give crude compound 8-2, which was used directly in the next step.

[0161] Step 2: Synthesis of compound 8-3

[0162] Compound 8-2 was dissolved in 20 mL of anhydrous DCM, dimethylhydroxylamine hydrochloride (3.0 g, 30 mmol) was added, and DIPEA (8.7 mL, 50 mmol) was slowly added dropwise with stirring. The reaction solution was stirred at room temperature overnight. After the reaction was completed, 30 mL of 1 M HCl was added to quench the reaction. The aqueous phase was extracted with dichloromethane (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain the crude product of 8-3. Finally, the pure product of compound 8-3 (3.72 g, yield 83%) was obtained by recrystallization from petroleum ether / ethyl acetate.

[0163] 1 H NMR (500MHz, CDCl3) δ8.77(s,1H),3.67(s,3H),3.34(s,3H),2.77(s,3H).

[0164] HRMS(ESI):m / z calcd for C7H11 N2O2S + [M+H] + :187.0536,found:187.0530

[0165] Step 3: Synthesis of compound 8-4

[0166] The magnesium ribbon for removing surface oxide film in advance is cut into small pieces (1.46g, 60mmol) and joins in 10mL anhydrous THF, under stirring, drops into several iodine elements, solution becomes brownish black rapidly.To reaction system, add the THF solution 10mL of 2-bromo-5-fluorotoluene (1.26mL, 10mmol), be warming up to backflow, until reaction successfully causes, now, solution color disappears, near colorless transparency.Remove the stirring reaction at room temperature after heating, and continue to drip the THF solution 10mL of remaining 2-bromo-5-fluorotoluene (5mL, 40mmol) by dropping funnel, keep system slightly backflow and continue reaction about 2h, obtain the THF solution of 4-fluoro-2-methylphenyl magnesium bromide of 1M / L.

[0167] Compound 8-3 (2.8 g, 15 mmol) was dissolved in 10 mL of anhydrous THF, and 20 mL of the 4-fluoro-2-methylphenylmagnesium bromide THF solution prepared above was added. The reaction solution was stirred at room temperature for 2 h. After the reaction was completed, 0.5 M HCl was added to the system until the system showed weak acidity, and the reaction was continued to stir for 30 min to quench the reaction. The aqueous phase was extracted with ethyl acetate (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain a crude product, which was purified by silica gel column chromatography to obtain pure compound 8-4 (1.65 g, yield 47%). 1 H NMR (500MHz, CDCl3) δ8.84 (s, 1H), 7.40 (dd, J=8.5, 5.8Hz, 1H), 7.02–6.93 (m, 2H), 2.54 (s, 3H), 2.39 (s, 3H). HRMS (ESI): m / z calcd forC 12 H 11 FNOS + [M+H] + :236.0540,found:236.0536

[0168] Step 4: Synthesis of compound 8-5

[0169] Under ice bath, compound 8-4 (0.8 g, 3.4 mmol) was added to 10 mL of methanol, and then sodium borohydride (0.26 g, 6.8 mmol) was slowly added under stirring. The reaction solution was warmed to room temperature and continued to stir for 2 h. After the reaction was completed, 5 mL of water was added to quench the reaction, and then the majority of the methanol was removed by concentration under reduced pressure. The aqueous phase was extracted with dichloromethane (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain the crude product of 8-5. Finally, the pure product of compound 8-5 (0.8 g, 99% yield) was obtained by recrystallization from petroleum ether / ethyl acetate. 1 H NMR (500MHz, CDCl3) δ8.54 (s, 1H), 7.55 (dd, J=8.6, 5.9Hz, 1H), 6.94 (td, J=8.4, 2.7Hz, 1H), 6.85 (dd, J= 9.6,2.7Hz,1H),6.16(d,J=3.4Hz,1H),3.16(d,J=3.6Hz,1H),2.40(s,3H),2.22(s,3H).HRMS(ESI):m / z calcd for C 12 H 13 FNOS + [M+H] + :238.0697,found:238.0694

[0170] Step 5: Synthesis of compound 8-6

[0171] Compound 8-5 (0.5 g, 2.1 mmol) was dissolved in 5 mL of anhydrous DCM, and phosphorus tribromide (0.32 mL, 3.4 mmol) was slowly added. The reaction was stirred at room temperature for 6 h. After the reaction was completed, cold saturated sodium bicarbonate solution was added to the reaction system to quench the reaction. The aqueous phase was extracted with dichloromethane (2 × 50 mL). The combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain the crude product 8-6, which was used directly in the next step. HRMS (ESI): m / z calcd for C 12 H 11 FNS + [M-Br] + :220.0591,found:220.0590

[0172] Step 6: Synthesis of compound 8-7

[0173] Compound 8-6 (0.3 g, 1 mmol) was added to 5 mL of anhydrous acetonitrile, followed by the addition of (R)-7-benzyloxy-3,4,12,12A-tetrahydro-1H-[1,4]azino[3,4-C]pyrido[2,1-F][1,2,4]triazine-6,8-dione (0.27 g, 0.83 mmol) and CsF (0.32 g, 2.1 mmol). The reaction mixture was heated to 70°C and stirred for 12 h. After completion of the reaction, the reaction mixture was quenched by adding 25 mL of saturated sodium bicarbonate solution and extracted with ethyl acetate (2 × 50 mL). The combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried. The resulting crude product was purified by column chromatography to obtain the racemic compound 8-7 (23 mg, 5% yield). HRMS (ESI): m / z calcd for C 29 H 28 N4O4FS + [M+H] + :547.1810,found:547.1804

[0174] Step 7: Synthesis of compound 8-8

[0175] Compound 8-7 (20 mg, 0.036 mmol) was added to 1 mL of N, N-dimethylacetamide, and lithium chloride (26 mg, 0.6 mmol) was added. The reaction solution was stirred at 80 ° C for 6 hours. After the reaction was completed, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M HCl aqueous solution and 1 mL of water were added, and stirring was continued for 1 hour. The precipitated solid in the reaction solution was collected by suction filtration and dried to obtain a crude product. Further recrystallization from isopropyl ether / chloroform gave a racemic compound 8-8 (11 mg, yield 65%).

[0176] White solid, mp 217.3-218.1 ℃. A mixture of diastereomers (1.7:1) was obtained in 65% yield. 1H NMR(500MHz,DMSO-d6)δ8.83(s,1.7H),8.11(s,1H),7.70(d,J=7.6Hz,1H),7.62(dd,J=6.9,3.1Hz,2H),7.56(dd,J=7.0,1.6Hz,1.7H),7.52(dd,J=8.6,6.2Hz,1.7H),7.39–7.35(m,2H),7.35–7.29(m,3.4H),7.06(s,1H),7.05–7.02(m,1.7H),7.00(d,J=3.2Hz,1H),6.99–6.96(m,1.7H),6.23(d,J=7.6Hz,1H),6.07(d,J=7.5Hz,1.7H),6.06(s,1.7H),5.91(s,1H),5.07(d,J=2.8Hz,1.7H),4.95–4.82(m,1.7H),4.82–4.71(m,1H),4.18–4.06(m,3H),4.03(dtd,J=11.5,6.7,6.2,2.7Hz,5.1H),3.46(s,1H),3.44(d,J=2.6Hz,1.7H),3.25–3.22(m,1.7H),3.15(d,J=1.4Hz,1H),3.05–2.99(m,1.7H),2.97(s,1H),2.35(s,5.1H),2.17(s,5.1H),2.13(s,3H),2.02(s,3H). 13 C NMR(125MHz,DMSO-d6)δ174.03,170.73,162.36,162.11(d,J=1.76Hz),160.17(d,J=2.65Hz),151.72,150.37,148.35,146.46,139.63,138.83(d,J=2.77Hz),137.73,137.46,137.40,136.18,135.9(d,J=2.4Hz),128.13,128.07,127.68,127.33,118.24,116.68,116.53,116.51(d,J=2.77Hz),116.37,115.29,112.45,112.32,112.28,112.16,111.72,72.76,65.80,65.52,65.47,65.41,64.76,64.17,64.03,62.33,18.55,18.33,15.12,11.16.HRMS(ESI):m / z calcd forC 22 H 22N4O4FS + [M+H] + :457.1341,found:457.1336

[0177] Example 9. Synthesis of 9-8

[0178] Referring to the method of Example 8, except that 4-methylthiazole-5-carboxylic acid was replaced with 4-methyl-5-carboxylic acid-1,3-oxazole, the final product was a diastereomeric mixture shown in Formula 9-8, in which the ratio of the two diastereoisomers was 2:1 (yield 66%).

[0179] Compound 9-8: white solid, mp 229.6-230.3℃. 1 H NMR(500MHz,DMSO-d6)δ8.56(s,2H),8.10(s,1H),7.70(d,J=7.6Hz,1H),7.62(d d,J=6.9,2.3Hz,2H),7.61–7.53(m,4H),7.38–7.36(m,2H),7.35–7.32(m,2H),7. 32–7.28(m,1H),7.24(dd,J=10.2,2.6Hz,2H),7.16(td,J=8.6,2.6Hz,2H),7.05( td,J=8.7,2.8Hz,1H),6.98(dd,J=10.0,2.8Hz,1H),6.23(d,J=7.6Hz,1H),6.07( d,J=7.5Hz,2H),5.91(s,1H),5.75(s,2H),5.11–5.04(m,2H),5.01–4.82(m,2H), 4.81–4.68(m,1H),4.20–4.07(m,3H),4.03(tq,J=11.3,3.6,2.7Hz,6H),3.49–3. 46(m,2H),3.46(d,J=2.8Hz,1H),3.25–3.21(m,2H),3.17–3.13(m,1H),3.06–2.9 9(m,2H),2.96–2.90(m,1H),2.31(s,6H),2.28(s,6H),2.12(s,3H),2.02(s,3H). 13C NMR(125MHz,DMSO-d6)δ184.10,174.03,170.75,164.16,162.36,160.20,155.95,153.78,150.38,148.75,146.47,14 5.82,144.37,139.96(d,J=8.8Hz),139.63(d,J=8.8Hz),137.67(d,J=7.3Hz),137.11(d,J=7.3Hz),135.93(d,J=3.2H z),133.90(d,J=2.8Hz),131.35,131.00,128.07,127.99,118.24,117.86,117.69,116.53,116.37,115.30,112.75,1 12.57,112.32,112.15,111.72,72.77,65.80,65.47,64.76,64.03,62.33,19.12,18.33,13.55,11.16.HRMS(ESI):m / z calcd for C 22 H 22 N4O5F + [M+H] + :441.1569,found:441.1572

[0180] Example 10. Synthesis of 10-7

[0181] Referring to the method of Example 8, except that 4-methylthiazole-5-carboxylic acid was replaced with 4-methylthiophene-5-carboxylic acid, the final product was a diastereomeric mixture represented by Formula 10-7 (18 mg, yield 72%), in which the ratio of the two diastereoisomers was 1.6:1.

[0182] White solid, mp 209.2-210.0℃. 1H NMR(500MHz,DMSO-d6)δ7.91(d,J=5.0Hz,1.6H),7.70(d,J=7.6Hz,1H),7.62(d,J=7.6Hz,1.6H),7.57(d,J=1.6Hz,1H),7.55(s,1H),7.49(dd,J=8.6,6.2Hz,1H),7.44(dd,J=8.5,5.9Hz,1.6H),7.38–7.35(m,2H),7.34–7.29(m,3.2H),7.26(d,J=5.1Hz,1H),7.21(dd,J=10.2,2.7Hz,1.6H),7.15–7.11(m,3.2H),7.01(td,J=8.7,2.9Hz,1H),6.97(dd,J=10.1,2.8Hz,1H),6.82(d,J=5.0Hz,1H),6.23(d,J=7.6Hz,1H),6.07(d,J=7.5Hz,1.6H),6.00(s,1.6H),5.75(s,1H),5.07(d,J=3.0Hz,2H),4.88(ddd,J=12.5,10.2,4.3Hz,1.6H),4.83–4.77(m,1H),4.17–4.07(m,3H),4.02(dq,J=11.3,3.4,2.7Hz,4.8H),3.44(s,2.6H),3.23(s,1H),3.16–3.12(m,1.6H),3.02(dd,J=4.2,1.5Hz,1H),2.95(ddd,J=13.7,12.1,4.3Hz,1.6H),2.28(s,4.8H),2.25(s,4.8H),2.17(s,3H),2.14(s,3H). 13C NMR (125MHz, DMSO-d6) δ189.57,174.03,170.71,163.65,162.36,161.68,155.94,151.61,148.74,145. 74,141.87,139.62,138.95,138.47,137.74,136.85,136.37,133.84,133.07,131.34,129.97,129.56,1 29.49,127.67,123.54,118.24,117.52,117.35,116.45,116.28,115.29,112.58,112.41,112.15,111. 98,111.76,72.77,65.80,65.47,65.03,64.76,64.03,18.96,18.55,16.11,13.55.HRMS(ESI):m / zcalcd for C 23 H 23 FN3O4S + [M+H] + :456.1388,found:456.1386

[0183] Example 11. Synthesis of 11-8-A and 11-8-B

[0184]

[0185] Step 1: Synthesis of compound 11-2

[0186] To a DCM solution (100 mL) of compound 11-1 (10.0 g, 76.9 mmol) was added pyridine (6.7 g, 84.6 mmol), followed by the addition of acetyl chloride (6.0 mL, 84.6 mmol) dropwise with stirring. The reaction mixture was stirred at room temperature for 12 h. After completion of the reaction, the reaction mixture was poured into 2M HCl (100 mL) and extracted with DCM (3 × 100 mL). The organic phases were combined and washed sequentially with water (1 × 100 mL) and saturated brine (1 × 100 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain the crude product. Purification by silica gel column chromatography gave pure compound 11-2 (12 g, 96% yield). 1 H NMR(500MHz, CDCl3)δ7.11–7.03(m,2H),6.95–6.88(m,1H),2.35(s,3H).HRMS(ESI):m / z calcdfor C8H6F2O2Na + [M+Na] +:195.0229,found:195.0228

[0187] Step 2: Synthesis of compound 11-3

[0188] At 0°C, compound 11-2 (12.0 g, 70 mmol) was dissolved in DCE (50 mL), and then anhydrous aluminum chloride (9.3 g, 70 mmol) was added portionwise with stirring. After the addition was complete, the reaction solution was brought to reflux and stirred for 12 hours. After the reaction was complete, 2M HCl (100 mL) was added to the reaction solution for quenching, and the mixture was extracted with DCM (3 × 100 mL). The organic phases were combined and washed with water (1 × 100 mL) and saturated brine (1 × 100 mL), dried over anhydrous sodium sulfate, filtered, and dried. The resulting crude product was purified by silica gel column chromatography to obtain pure compound 11-3 (9.7 g, 81%). 1 H NMR (500MHz, CDCl3) δ12.57 (d, J=1.3Hz, 1H), 7.52 (ddd, J=9.2, 5.5, 2.3Hz, 1H), 6.72 (td, J=9.3, 6.6Hz, 1H), 2.62 (s, 3H). HRMS (ESI): m / z calcd for C8H6F2O2Na + [M+Na] + :195.0229,found:195.0231

[0189] Step 3: Synthesis of compounds 11-4 to 11-8 was carried out by referring to the method of Example 1, except that 4'-chloro-2'-hydroxyacetophenone (1-1) was replaced by compound 11-3, and finally two diastereomers corresponding to compound 11-8 were obtained: compound 11-8-A and compound 11-8-B.

[0190] Compound 11-8-A: white solid. 1H NMR(500MHz,DMSO-d6)δ11.68(s,1H),8.98(s,1H),7.20(t,J=7.6Hz,1H),7.15–7.08(m,1H),7 .06(d,J=7.7Hz,1H),5.99(s,1H),5.69(d,J=7.7Hz,1H),5.58(d,J=14.6Hz,1H),5.07(d,J=14. 7Hz,1H),4.81(dd,J=9.9,3.1Hz,1H),4.44(dd,J=13.5,2.5Hz,1H),3.78(dd,J=10.8,3.1Hz,1 H),3.73(dd,J=11.6,3.3Hz,1H),3.59(t,J=10.4Hz,1H),3.44–3.40(m,1H),3.16–3.10(m,1H). 13 C NMR(125MHz,DMSO-d6)δ177.04,160.96,157.33,156.81,151.65,138.22,127.02,126.90,124.06,123.93, 119.90,115.53,112.57,112.44,110.96,110.85,70.20,68.03,65.54,64.55,61.81,45.37.HRMS(ESI):m / z calcd for C 21 H 17 F2N4O6 + [M+H] + :459.1111,found:459.1111 Compound 11-8-B: white solid. HRMS (ESI): m / z calcd for C 21 H 17 F2N4O6 + [M+H] + :459.1111,found:459.1108

[0191] Example 12. Synthesis of 12-12-A and 12-12-B

[0192]

[0193] Step 1: Synthesis of compound 12-5

[0194] Compound 12-4 (4 g, 25.8 mmol) was dissolved in 15 mL of chlorobenzene and heated to 100°C with stirring. BPO (0.62 g, 2.58 mmol) and dibromohydantoin (8.87 g, 31.0 mmol) were then added to the reaction mixture. The temperature was continued to reflux and the reaction was allowed to react overnight. After the reaction, the chlorobenzene was removed by concentration under reduced pressure. The residue was dissolved in DCM and filtered to remove insoluble matter. The filtrate was dried to obtain the crude product, which was then purified by silica gel column chromatography to obtain pure compound 12-5 (3 g, 51% yield). 1 H NMR (500MHz, CDCl3) δ8.59 (s, 1H), 4.56 (s, 2H), 4.48 (q, J = 7.1Hz, 2H), 1.45 (t, J = 7.1Hz, 3H). HRMS (ESI): m / zcalcd for C7H9NBrO3 + [M+H] + :233.9761,found:233.9759

[0195] Step 2: Synthesis of compound 12-6

[0196] Under a nitrogen atmosphere, compound 12-5 (2 g, 8.6 mmol) and triphenylphosphine (2.7 g, 10.3 mmol) were added to 15 mL of toluene and refluxed for 4 h. After the reaction, the filtrate was filtered and the filter cake was washed with toluene to obtain crude compound 12-6, which was used directly in the next reaction without further purification. HRMS (ESI): m / z calculated for C 25 H 23 NPO3 + [M+H] + :416.1411,found:416.1412

[0197] Step 3: Synthesis of compound 12-7

[0198] Crude compound 12-6 (1.5 g, 3.0 mmol) was dissolved in 10 mL of anhydrous acetonitrile at 0°C. 2,3-Difluorobenzaldehyde (0.85 g, 6.0 mmol) and DBU (0.55 g, 3.6 mmol) were then added sequentially with stirring. The reaction mixture was heated to reflux and allowed to react overnight. After completion of the reaction, the solvent was removed by concentration under reduced pressure, and the product was directly purified by silica gel column chromatography to obtain pure compound 12-7 (0.8 g, 94% yield). 1H NMR(500MHz, CDCl3)δ8.09(d,J=0.9Hz,1H),7.11(dtd,J=10.0,7.7,2.0Hz,1H),7.06–6.93(m,2H),6.87 (d,J=12.0Hz,1H),6.72(d,J=12.0Hz,1H),4.45(q,J=7.1Hz,2H),1.43(t,J=7.2Hz,3H).HRMS(ESI):m / z calcd forC 14 H 12 NF2O3 + [M+H] + :280.0780,found:280.0773

[0199] Step 4: Synthesis of compound 12-8

[0200] Compound 12-7 (0.8 g, 2.9 mmol) was dissolved in ethanol / water (5 mL / 1 mL) and LiOH·H2O (0.24 g, 5.8 mmol) was added with stirring. The mixture was allowed to react at room temperature for 2 h. After completion of the reaction, the ethanol was removed by concentration under reduced pressure. 2M HCl was then added dropwise to the residue with stirring until the pH reached approximately 6. The mixture was filtered and the filtrate was discarded. The filter cake was washed with water and dried to obtain 0.65 g of crude compound 12-8, which was used directly in the next reaction without further purification. HRMS (ESI): m / z calculated for C 12 H8NF2O3 + [M+H] + :252.0467,found:252.0461

[0201] Step 5: Synthesis of compound 12-9

[0202] Compound 12-8 (0.65 g, 2.6 mmol) was dissolved in 5 mL of anhydrous DCM. Thionyl chloride (0.38 mL, 5.2 mmol) was added dropwise with stirring, followed by a catalytic amount of DMF. The mixture was refluxed for 4 h. After completion of the reaction, 10 mL of carbon tetrachloride and anhydrous aluminum chloride (0.78 g, 5.2 mmol) were added after the system returned to room temperature. The temperature was raised to reflux and the reaction was allowed to proceed overnight. After completion of the reaction, 10 mL of 1 M HCl was added dropwise to quench the reaction. The aqueous phase was extracted with DCM (1 × 50 mL). The combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain crude compound 12-9. Finally, pure compound 12-9 (0.55 g, 92% yield) was obtained by silica gel column chromatography. 1H NMR (500MHz, CDCl3) δ8.97 (s, 1H), 8.35 (ddd, J = 9.2, 5.5, 2.0Hz, 1H), 7.37 (td, J = 8.9, 7.5Hz, 1H), 7.28 (s, 1H), 7.07 (d, J = 12.0Hz, 1H). HRMS (ESI): m / z calcd for C 12 H6NF2O2 + [M+H] + :234.0362,found:234.0363

[0203] Step 6: Synthesis of compound 12-10

[0204] Under ice, compound 12-9 (0.55 g, 2.36 mmol) was added to 10 mL of ethanol, and sodium borohydride (0.09 g, 2.36 mmol) was slowly added with stirring. The reaction solution was warmed to room temperature and stirred for 2 h. After completion of the reaction, 5 mL of water was added to quench the reaction, and then the solution was concentrated under reduced pressure to remove most of the ethanol. The aqueous phase was extracted with dichloromethane (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain the crude product. Finally, pure compound 12-10 (0.48 g, 87% yield) was obtained by recrystallization from ethyl acetate. 1 H NMR (500MHz, DMSO-d6) δ9.13 (s, 1H), 7.48 (dq, J=17.4, 8.5Hz, 2H), 7.04 (d, J= 11.8Hz,1H),6.97(d,J=11.8Hz,1H),6.17(s,1H),5.84(s,1H).HRMS(ESI):m / z calcd for C 12 H6NF2O + [M-OH] + :218.0412,found:218.0410

[0205] Step 7: Synthesis of compound 12-11

[0206] Compound 12-10 (0.4 g, 1.7 mmol) was added to a 50% (w / w)-T4P / EA solution (2 mL, 2.4 mmol) in n-butylphosphoric acid (50% ethyl acetate solution), and the mixture was stirred at room temperature. (R)-7-Benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione (0.26 g, 0.8 mmol) and 2 mL of ethyl acetate were then added. The reaction mixture was heated to 110°C and stirred for 5 hours. After completion of the reaction, the reaction mixture was quenched by adding 15 mL of saturated sodium bicarbonate solution and extracted with ethyl acetate (2 × 50 mL). The combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and dried in spun-drying. The resulting crude product was purified by column chromatography (dichloromethane:methanol = 100:1 → 50:1) to yield 103 mg and 73 mg of pure compounds 12-11-A and 12-11-B, respectively (total yield 42%). The resulting compounds were analyzed by liquid chromatography, with retention times of 7.10 min for compound 12-11-A and 7.13 min for compound 12-11-B. Compounds 12-11-A and 12-11-B are two diastereomers of formula (12-11) with respect to *C.

[0207] Compound 12-11-A: 1 H NMR(500MHz,DMSO-d6)δ9.40(s,1H),7.58–7.54(m,2H),7.41–7.36(m,2H),7.35–7.30(m,1H),7.27–7.20(m,1H),7.17–7.1 0(m,2H),7.07(dd,J=11.8,1.5Hz,1H),6.78(d,J=7.7Hz,1H),6.19(s,1H),5.72(d,J=7.7Hz,1H),5.25(d,J=11.0Hz,1H),5 .08(d,J=11.0Hz,1H),4.45(dd,J=13.5,2.5Hz,1H),4.22(dd,J=9.9,3.1Hz,1H),3.66(dd,J=11.6,3.3Hz,1H),3.53(dd,J= 10.7,3.1Hz,1H),3.29(d,J=10.3Hz,1H),3.22(td,J=11.7,2.7Hz,1H),2.97(ddd,J=13.4,11.7,3.5Hz,1H).HRMS(ESI):m / z calcd for C 29 H 23 N4F2O5 + [M+H]+ :545.1632,found:545.1631

[0208] Compound 12-11-B: 1 H NMR(500MHz,DMSO-d6)δ9.26(s,1H),7.66(dd,J=8.8,5.1Hz,1H),7.63–7.57(m,1H),7.55–7.51(m,2H),7.38–7.34(m,2H), 7.32–7.29(m,1H),7.11(d,J=11.9Hz,1H),7.04(dd,J=11.8,1.5Hz,1H),6.74(d,J=7.6Hz,1H),6.13(s,1H),5.84(d,J=7.7 Hz,1H),5.17(d,J=10.8Hz,1H),5.10(d,J=10.8Hz,1H),4.39(dd,J=13.4,2.5Hz,1H),4.09(dd,J=9.8,3.1Hz,1H),3.62(dd ,J=11.6,3.3Hz,1H),3.55(dd,J=10.6,3.1Hz,1H),3.22–3.12(m,2H),2.86(ddd,J=13.5,11.7,3.5Hz,1H).HRMS(ESI):m / z calcd forC 29 H 23 N4F2O5 + [M+H] + :545.1632,found:545.1628

[0209] Step 8: Synthesis of compound 12-12-A

[0210] Compound 12-11-A (93 mg, 0.17 mmol) was added to 1 mL of N, N-dimethylacetamide, lithium chloride (42 mg, 1 mmol) was added, and the reaction solution was stirred at 80 ° C for 6 h. After the reaction was completed, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M HCl aqueous solution and 1 mL of water were added, and stirring was continued for 1 h. The solid precipitated in the reaction solution was collected by suction filtration and dried to obtain a crude compound 12-12-A. Further recrystallization from isopropyl ether / chloroform gave pure compound 12-12-A (70 mg, 90% yield).

[0211] White solid. 1H NMR (500MHz, DMSO-d6) δ11.70(s,1H),9.41(s,1H),7.38–7.32(m,1H),7.28(dd,J=9. 0,5.1Hz,1H),7.17–7.06(m,2H),6.69(d,J=7.7Hz,1H),6.21(s,1H),5.56(d,J=7.6H z,1H),4.43(dd,J=13.3,2.4Hz,1H),4.24(dd,J=9.4,3.7Hz,1H),3.68(dd,J=11.6,3 .4Hz,1H),3.56–3.48(m,2H),3.40–3.37(m,1H),3.05(ddd,J=13.3,11.7,3.5Hz,1H). 13 C NMR(125MHz,DMSO-d6)δ171.60,161.54,160.99,158.79,153.38,138.92,129.12,128.93,126.50,120.71,1 20.53,120.44,117.69,117.56,116.13,115.54,110.93,70.12,68.23,65.96,63.56,45.82.HRMS(ESI):m / z calcd for C 22 H 17 N4F2O5 + [M+H] + :455.1162,found:455.1160

[0212] Step 6: Synthesis of compound 12-12-B

[0213] Compound 12-11-B (63 mg, 0.12 mmol) was added to 1 mL of N,N-dimethylacetamide, followed by the addition of lithium chloride (42 mg, 1 mmol). The reaction mixture was stirred at 80°C for 6 h. After completion of the reaction, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M aqueous HCl, and 1 mL of water were added, and stirring continued for 1 h. The precipitated solid from the reaction mixture was collected by filtration and dried to obtain crude compound 12-12-B. Further recrystallization from isopropyl ether / chloroform afforded pure compound 12-12-B (50 mg, 94% yield). A white solid was obtained. 1H NMR (500MHz, DMSO-d6) δ11.68(s,1H),9.27(s,1H),7.70(dd,J=8.9,5.1Hz,1H),7.60(q,J=8 .8Hz,1H),7.12(d,J=11.8Hz,1H),7.06(dd,J=11.7,1.5Hz,1H),6.66(d,J=7.6Hz,1H),6.16 (s,1H),5.69(d,J=7.6Hz,1H),4.45–4.33(m,1H),4.14(dd,J=9.7,3.2Hz,1H),3.64(dd,J=1 1.7,3.2Hz,1H),3.55(dd,J=10.7,3.2Hz,1H),3.47(m,1H),3.35(m,1H),2.99–2.90(m,1H). 13 C NMR(125MHz,DMSO-d6)δ171.33,160.97,159.79,157.64,153.10,138.21,128.76,128.53,125.68,125.61,1 20.30,119.88,117.89,117.75,115.53,115.46,110.70,69.18,67.73,65.43,63.43,45.35.HRMS(ESI):m / z calcd for C 22 H 17 N4F2O5 + [M+H] + :455.1162,found:455.1166.

[0214] Example 13. Synthesis of 13-16-A and 13-16-B

[0215]

[0216] Step 1: Synthesis of compound 13-10

[0217] The synthesis of compound 13-10 was carried out according to the method in Example 12.

[0218] Step 2: Synthesis of compound 13-11

[0219] At 0°C under a nitrogen atmosphere, compound 13-5 (1,2-bis(2,3-difluorophenyl) disulfide) (0.6 g, 2 mmol) was dissolved in acetonitrile / water (8 mL / 2 mL), and zinc powder (0.52 g, 8 mmol) was added. Ferric chloride (0.65 g, 4 mmol) was added portionwise with stirring. The reaction solution was allowed to return to room temperature and the reaction continued for 3 h. Compound 13-10 (0.9 g, 4 mmol) was then added and allowed to react overnight. After completion of the reaction, the insoluble material was filtered through celite, and the filter cake was washed with EA. The filtrate was collected and washed sequentially with water (1 × 50 mL) and saturated brine (1 × 50 mL). The crude product was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain the product. It was then purified by silica gel column chromatography (petroleum ether:ethyl acetate = 50:1) to obtain pure compound 13-11 (0.7 g, 91% yield).

[0220] 1 H NMR (500MHz, CDCl3) δ8.28 (s, 1H), 7.13–6.97 (m, 3H), 4.46 (q, J = 7.1Hz, 2H), 4.19 (d, J = 0.9Hz, 2H), 1.43 (t, J = 7.2Hz, 3H).

[0221] HRMS(ESI):m / z calcd for C 13 H 12 SF2NO3 + [M+H] + :300.0501,found:300.0495

[0222] Step 3: Synthesis of compound 13-12

[0223] Compound 13-11 (0.7 g, 2.3 mmol) was dissolved in ethanol / water (5 mL / 1 mL). LiOH·H₂O (0.2 g, 4.6 mmol) was added with stirring and allowed to react at room temperature for 2 h. After completion of the reaction, the ethanol was removed by concentration under reduced pressure. 2M HCl was then added dropwise to the residue with stirring until the pH reached approximately 6. The mixture was filtered and the filtrate was discarded. The filter cake was washed with water and dried to obtain 0.56 g of crude compound 13-12, which was used directly in the next step without further purification.

[0224] HRMS(ESI):m / z calcd for C 11 H8SF2NO3 + [M+H] + :272.0188,found:272.0184

[0225] Step 4: Synthesis of compound 13-13

[0226] Compound 13-12 (0.5 g, 1.8 mmol) was added to 10 g of polyphosphoric acid and stirred at 150°C for 24 h. After completion of the reaction, the reaction solution was slowly added dropwise to a cold saturated sodium bicarbonate solution. The aqueous phase was extracted with EA (2 × 100 mL). The combined organic phases were washed with saturated brine (1 × 50 mL). The crude product was dried over anhydrous sodium sulfate and then spin-dried to dryness. Purification by silica gel column chromatography afforded pure compound 13-13 (0.2 g, 46% yield).

[0227] 1 H NMR (500MHz, CDCl3) δ8.49 (s, 1H), 7.88 (ddd, J = 8.9, 5.3, 1.9Hz, 1H), 7.30–7.27 (m, 1H), 3.95 (s, 2H).

[0228] HRMS(ESI):m / z calcd for C 11 H6SF2NO2 + [M+H] + :254.0082,found:254.0082

[0229] Step 5: Synthesis of Compounds 13-14

[0230] Under ice, compound 13-13 (0.2 g, 0.8 mmol) was added to 10 mL of ethanol, and sodium borohydride (0.06 g, 1.6 mmol) was slowly added with stirring. The reaction solution was warmed to room temperature and stirred for 2 h. After completion, 5 mL of water was added to quench the reaction, and the mixture was then concentrated under reduced pressure to remove most of the ethanol. The aqueous phase was extracted with dichloromethane (2 × 50 mL), and the combined organic phases were washed with saturated brine (1 × 50 mL), dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain the crude product. Finally, pure compound 13-14 (0.18 g, 90% yield) was obtained by recrystallization from ethyl acetate.

[0231] 1 H NMR (500MHz, DMSO-d6) δ8.69(s,1H),7.54–7.42(m,2H),6.62(d,J=4.6Hz,1H),6.33(d,J=4.6Hz,1H),4.08–3.98(m,2H).

[0232] HRMS(ESI):m / z calcd for C 11 H6SF2NO + [M-OH] + :238.0133,found:238.0131

[0233] Step 6: Synthesis of compounds 13-15

[0234] Compound 13-14 (0.18 g, 0.7 mmol) was added to a 50% (w / w)-T4P / EA solution (2 mL, 2.4 mmol) in n-butylphosphoric acid (50% ethyl acetate solution). (R)-7-benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione (0.16 g, 0.5 mmol) and 2 mL of ethyl acetate were then added. The reaction mixture was heated to 110°C and stirred for 5 hours. After completion of the reaction, the reaction mixture was quenched by adding 15 mL of saturated sodium bicarbonate solution and extracted with ethyl acetate (2 × 50 mL). The combined organic phases were washed with saturated brine (1×50 mL), dried over anhydrous sodium sulfate, filtered, and dried in spun-dry form. The resulting crude product was purified by column chromatography to yield 20 mg and 14 mg of pure compounds 13-15-A and 13-15-B, respectively (total yield 12%). The resulting compounds were analyzed by liquid chromatography, with retention times of 7.02 min for compound 13-15-A and 7.04 min for compound 13-15-B. Compounds 13-15-A and 13-15-B are two diastereomers of formula (13-15) with respect to *C.

[0235] Compound 13-15-A: HRMS (ESI): m / z calculated for C 28 H 22 N4F2O5S + [M+H] + :565.1352,found:565.1350

[0236] Compound 13-15-B: HRMS (ESI): m / z calculated for C 28 H 22 N4F2O5S + [M+H] + :565.1352,found:565.1349

[0237] Step 8: Synthesis of compound 13-16-A

[0238] Compound 13-15-A (20 mg, 0.035 mmol) was added to 1 mL of N, N-dimethylacetamide, lithium chloride (15 mg, 0.35 mmol) was added, and the reaction solution was stirred at 80 ° C for 6 h. After the reaction was completed, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M HCl aqueous solution and 1 mL of water were added, and stirring was continued for 1 h. The solid precipitated in the reaction solution was collected by suction filtration and dried to obtain a crude compound 13-16-A. Further recrystallization from isopropyl ether / chloroform gave a pure compound 13-16-A (15 mg, 90% yield).

[0239] White solid.HRMS(ESI):m / z calcd for C 21 H 17 N4F2O5S + [M+H] + :475.0883,found:475.0880

[0240] Step 9: Synthesis of compound 13-16-B

[0241] Compound 13-15-B (14 mg, 0.025 mmol) was added to 1 mL of N, N-dimethylacetamide, lithium chloride (11 mg, 0.25 mmol) was added, and the reaction solution was stirred at 80 ° C for 6 h. After the reaction was completed, the reaction system was placed in an ice bath, and 0.5 mL of acetone, 2 mL of 0.5 M HCl aqueous solution and 1 mL of water were added, and stirring was continued for 1 h. The solid precipitated in the reaction solution was collected by suction filtration and dried to obtain a crude compound 13-16-B. Further recrystallization from isopropyl ether / chloroform gave pure compound 13-16-B (11 mg, 90% yield).

[0242] White solid.HRMS(ESI):m / z calcd for C 21 H 17 N4F2O5S + [M+H] + :475.0883,found:475.0878

[0243] Example 14. Synthesis of 14-15-A and 14-15-B

[0244] By referring to the method of Example 13, two diastereomers corresponding to compound 14-15 were finally obtained: compound 14-15-A and compound 14-15-B (see claims or description for their structures, the same below).

[0245] Compound 14-15-A: HRMS (ESI): m / z calculated for C 21 H 17 N4F2O5Se + [M+H] + :523.0327,found:523.0325

[0246] Compound 14-15-B: HRMS (ESI): m / z calculated for C 21 H 17 N4F2O5Se + [M+H] + :523.0327,found:523.0330

[0247] Example 15. Synthesis of 15-12-A and 15-12-B

[0248] By referring to the method of Example 12, two diastereomers corresponding to compound 15-12 were finally obtained: compound 15-12-A and compound 15-12-B.

[0249] Compound 15-12-A: HRMS (ESI): m / z calculated for C 22 H 19 N4O5[M+H] + :419.1350,found:419.1352

[0250] Compound 15-12-B: HRMS (ESI): m / z calculated for C 22 H 19 N4O5[M+H] + :419.1350,found:419.1353

[0251] Example 16. Synthesis of 16-12-A and 16-12-B

[0252] By referring to the method of Example 12, two diastereomers corresponding to compound 16-12 were finally obtained: compound 16-12-A and compound 16-12-B.

[0253] Compound 16-12-A: HRMS (ESI): m / z calculated for C 22 H 18 FN4O5[M+H] + :437.1256,found:437.1255

[0254] Compound 16-12-B: HRMS (ESI): m / z calculated for C 22 H 18 FN4O5[M+H] + :437.1256,found:437.1257

[0255] Example 17 Inhibitory Effects of Compounds Disclosed in the Present Invention on Influenza Virus Polymerase Expressed in HEK-293T Cells

[0256] HEK-293T cells were trypsinized and counted, then suspended in DMEM medium containing 10% fetal bovine serum and then cultured at 1.5 × 10 4 Cells / well were seeded in a 96-well plate with 100 μL of empty volume per well. The 96-well plate was cultured at 37°C / 5% CO2 for 24 hours. After 24 hours, 20 μL of DMEM solution containing a certain concentration of the test compound was added, and 20 μL of DMEM solution was added to the control wells, and the cells were cultured in a cell culture incubator for another 2 hours. Subsequently, a plasmid transfection solution (plasmids including PA, PB1, PB2, NP, Luciferase and Renilla) was added to each well, and the culture was continued for 24 hours. The culture medium was removed, and 100 μL / well of PBS solution was added to gently wash the cells. After removing the PBS, 1×CLB cell lysate was added to each well. After shaking at room temperature for 20 minutes, the lysate in the plate was transferred to a 1.5 mL centrifuge tube, centrifuged at 12,000 rpm for 2 minutes, 20 μL of the supernatant was placed in a 96-well white plate, and the Luciferase substrate and Renilla substrate were added in sequence, and the luminescence value was detected using an enzyme reader. The regression curve and regression equation were obtained by regression analysis, and the IC value of the compound described in the present invention was calculated. 50 In Table 1, PA / WT represents wild-type influenza PA; PA / I38T represents I38T mutant influenza PA.

[0257] Table 1. IC values of the hydroxypyridone compounds and baloxavir of the present invention 50 Value and RI value

[0258]

[0259]

[0260] Examples 1 to 16 and IC of baloxavir 50The RI values are shown in Table 1. The results demonstrate that the hydroxypyridone compounds disclosed herein, particularly the compounds prepared in Examples 14 and 15, effectively inhibit influenza A virus RNA polymerase in HEK-293T cells. However, the inhibitory activity of baloxavir against the PA / I38T-resistant strain was significantly reduced. The RI of the hydroxypyridone compounds disclosed herein is lower than that of baloxavir, indicating that the derivatives disclosed herein are less susceptible to influenza A PA / I38T mutant strains and are superior to baloxavir.

[0261] Example 18 Antiviral Effect of the Compounds Disclosed in the Present Invention in MDCK Cells Infected with Influenza A Virus

[0262] MDCK cells were trypsinized and counted, then suspended in DMEM medium containing 10% fetal bovine serum and then cultured at 1.5×10 5 MDCK cells were seeded into 24-well plates at 500 μL of culture medium per well. The plates were incubated at 37°C / 5% CO2 for 24 hours. The culture medium was removed and 500 μL of fresh culture medium was added. After adding a certain concentration of the test compound, influenza virus was inoculated into the 24-well plates at a multiplicity of infection (MOI = number of viruses / number of cells) of 0.1. The plates were incubated in a cell culture incubator for 24 hours. The supernatant was collected and the viral TCID was determined. 50 The EC value of the compound of the present invention was calculated by regression analysis to obtain the regression curve and regression equation. 50 value.

[0263] Table 2. EC values of the hydroxypyridone compounds and baloxavir according to the present invention 50 value

[0264]

[0265] Examples 1, 2, 12 and EC of baloxavir 50 The values are shown in Table 2. The results show that the hydroxypyridone compounds (1-6-A, 1-6-B, 2-6-A, 2-6-B, 12-12-A, 12-12-B) obtained in the present invention can effectively inhibit influenza A virus in MDCK cells. Examples 1, 2, and 12 have inhibitory activities comparable to baloxavir against wild-type strains, and Example 12 has an inhibitory activity against the I38T mutant strain that is significantly better than baloxavir.

Claims

1. A pyridone derivative, characterized in that Having a structure represented by formula (I) or formula (III), or a pharmaceutically acceptable salt thereof, ； in R1 is selected from hydrogen, halogen, C1~C6 alkyl, R1 is one or multiple independent of each other; R2 is selected from non-existent, C1~C6 alkyl or C1~C3 alkyl acyl or ; R3 is selected from hydrogen or ; X is selected from N, O, S, Se; when X is O, S, Se, R2 does not exist; Ring A is selected from: 。 2. The pyridone derivative according to claim 1, characterized in that In formula (I) or formula (III), the C atom corresponding to * is in S configuration or R configuration or a mixture of S configuration and R configuration: ； R3 and X are as defined in claim 1; R1 is H, halogen, C1~C3 alkyl, R1 is 1 or 2 independent of each other; R2 is selected from the group consisting of: not existing, C1~C3 alkyl, or .

3. The pyridone derivative according to claim 1 or 2, characterized in that It has the structure represented by the following formula (Ia), (Ib), (Ic), and (III-a): ； R1 is H, halogen, C1~C3 alkyl, R1 is 1 or 2 independent of each other, R3 is H or .

4. The pyridone derivative according to claim 1, characterized in that Having any of the following structures: ； ； ； ； ； 。 5. An intermediate for preparing the pyridone derivative according to any one of claims 1 to 4, characterized in that: Having a structure shown in any of the following formulas: ； R1, R2 and X are as defined in claim 1.

6. The intermediate according to claim 5, characterized in that Having a structure shown in any of the following formulas: 。 7. A method for synthesizing a pyridone derivative according to any one of claims 1 to 4, characterized in that: include: The compound represented by formula (I-1) or formula (III-1) is reduced under the action of sodium borohydride to obtain the intermediate represented by formula (I-2) or formula (III-2). The intermediate (I-2) or formula (III-2) is reacted with (R)-7-benzyloxy-3,4,12,12a-tetrahydro-1H-[1,4]azino[3,4-c]pyrido[2,1-f][1,2,4]triazine-6,8-dione in the presence of n-butylphosphoric anhydride to obtain intermediate (I-3) or intermediate (III-3). The intermediate (I-3) or intermediate (III-3) is reduced with LiCl to remove the benzyl group to obtain a pyridone derivative represented by formula (I) or formula (III): ； 。 8. The method for synthesizing a pyridone derivative according to claim 7, wherein: When the intermediate (I-1) has a structure represented by formula (I-1-1), the intermediate (I-1) is obtained by reacting the intermediate (I-1-1-1) with tert-butyl nitrite: When the intermediate (I-1) has a structure represented by formula (I-1-2), the intermediate (I-1) is obtained by reacting the intermediate (I-1-2-1) with tert-butyl nitrite: When the intermediate (I-1) has a structure represented by formula (I-1-3), the intermediate (I-1) is obtained by reacting the intermediate (I-1-3-1) with polyphosphoric acid: When the intermediate (III-1) has a structure represented by formula (III-1-1), the intermediate (III-1) is obtained by first reacting the intermediate (III-1-1-1) with thionyl chloride and then reacting with aluminum trichloride: ； Wherein, X1 is S or Se; R2 is selected from or .

9. Use of the pyridone derivative according to any one of claims 1 to 4 in the preparation of influenza drugs.

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