A baicalin derivative and its application

Abstract

This invention discloses a baicalin derivative or its pharmaceutical salt, with the following general structural formula: By optimizing the structure of baicalin, this invention obtains a baicalin derivative. Through antibacterial activity tests on common Gram-positive bacteria such as drug-resistant Staphylococcus aureus and Gram-negative bacteria such as Escherichia coli and Klebsiella pneumoniae, it was found that this type of compound has excellent anti-drug-resistant bacterial activity and has great development value in the preparation of anti-infective therapeutic drugs.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical chemistry technology, specifically, it relates to a baicalin derivative and its applications. Background Technology

[0002] Excessive or inappropriate use of quinolone antibiotics can increase bacterial resistance, with methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Acinetobacter baumannii (CRBBA), and drug-resistant Klebsiella pneumoniae becoming major types of nosocomial infections (Li Ping et al., Journal of Rational Clinical Drug Use, 2023, 4, 178-181; Niu Yinghui et al., Chinese Scientific and Technological Periodicals Database (Full Text Edition) Medicine and Health, 2022, 7, 262-264; Xing Lingyi et al., Journal of Tianjin University of Traditional Chinese Medicine, 2023, 1, 127-136). To address this global problem of antibiotic resistance, developing novel antibiotics with different mechanisms of action than quinolone antibiotics has become one effective solution.

[0003] Traditional Chinese medicine has a long history of disease prevention and treatment, with a wide range of sources and few side effects, making it a potential source for developing novel antibacterial drugs. Scutellaria baicalensis, a herbaceous plant belonging to the Lamiaceae family, possesses various pharmacological effects, among which baicalein, a flavonoid component, exhibits antibacterial activity (Feng Qianqian et al., Journal of Yichun University, 2022, 9, 21-24). However, baicalein's antibacterial activity is relatively weak, especially against methicillin-resistant Staphylococcus aureus (MRSA), with a MIC of 128-256 ug / mL (Zhou Liuru et al., Modern Hospital, 2011, 11, 34-35). Therefore, structural optimization of baicalein is needed to enhance its antibacterial activity. Summary of the Invention

[0004] The purpose of this invention is to provide a baicalin derivative.

[0005] Another object of the present invention is to provide the use of the baicalin derivative in the preparation of antibacterial drugs.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a baicalin derivative or a medicinal salt thereof, with the following general structural formula:

[0008]

[0009] L is selected from -(CH2)n-; n is selected from positive integers from 1 to 10;

[0010] R1 is selected from hydrogen, deuterium, hydroxyl, and halogens (fluorine, bromine, chlorine, iodine);

[0011] R2 is selected from hydrogen, deuterium, hydroxyl, and halogens (fluorine, bromine, chlorine, iodine);

[0012] R3 is selected from hydrogen, deuterium, hydroxyl, and halogens (fluorine, bromine, chlorine, iodine);

[0013] R4 is selected from hydrogen, deuterium, hydroxyl, and halogens (fluorine, bromine, chlorine, iodine);

[0014] Selected from

[0015] R5 is selected from

[0016] R6 is selected from hydrogen, deuterium, halogens (fluorine, bromine, chlorine, iodine), C1-C10 alkyl, and C1-C10 alkoxy.

[0017] R7 is selected from hydrogen, deuterium, halogens (fluorine, bromine, chlorine, iodine), C1-C10 alkyl, and C1-C10 alkoxy.

[0018] R8 is selected from hydrogen, deuterium, halogens (fluorine, bromine, chlorine, iodine), C1-C10 alkyl, and C1-C10 alkoxy.

[0019] R9 is selected from hydrogen, deuterium, halogens (fluorine, bromine, chlorine, iodine), C1-C10 alkyl, and C1-C10 alkoxy.

[0020] R 10 Selected from hydrogen, deuterium, halogens (fluorine, bromine, chlorine, iodine), C1-C10 alkyl, and C1-C10 alkoxy.

[0021] Preferably, in the baicalin derivative,

[0022] L is selected from -(CH2)n-; n is selected from 1, 2, 3, 4, 5;

[0023] R1 is selected from hydrogen, deuterium, hydroxyl, fluorine, bromine, chlorine, and iodine;

[0024] R2 is selected from hydrogen, deuterium, hydroxyl, fluorine, bromine, chlorine, and iodine;

[0025] R3 is selected from hydrogen, deuterium, hydroxyl, fluorine, bromine, chlorine, and iodine;

[0026] R4 is selected from hydrogen, deuterium, hydroxyl, fluorine, bromine, chlorine, and iodine;

[0027] Selected from

[0028] R5 is selected from

[0029] R6 is selected from hydrogen, deuterium, fluorine, bromine, chlorine, iodine, methyl, ethyl, isopropyl, methoxy, ethoxy, isopropoxy, tert-butoxy, and n-butoxy.

[0030] R7 is selected from hydrogen, deuterium, fluorine, bromine, chlorine, iodine, methyl, ethyl, isopropyl, methoxy, ethoxy, isopropoxy, tert-butoxy, and n-butoxy.

[0031] R8 is selected from hydrogen, deuterium, fluorine, bromine, chlorine, iodine, methyl, ethyl, isopropyl, methoxy, ethoxy, isopropoxy, tert-butoxy, and n-butoxy.

[0032] R9 is selected from hydrogen, deuterium, fluorine, bromine, chlorine, iodine, methyl, ethyl, isopropyl, methoxy, ethoxy, isopropoxy, tert-butoxy, and n-butoxy.

[0033] R 10 Selected from hydrogen, deuterium, fluorine, bromine, chlorine, iodine, methyl, ethyl, isopropyl, methoxy, ethoxy, isopropoxy, tert-butoxy, and n-butoxy.

[0034] Most preferably, the structure of the baicalin derivative is selected from one of the following structures:

[0035]

[0036] In a second aspect, the present invention provides the use of the baicalin derivative or its pharmaceutical salt in the preparation of an antibacterial medicament.

[0037] The bacteria referred to are methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, etc.

[0038] A third aspect of the present invention provides the use of the baicalin derivative or its pharmaceutical salt in the preparation of a medicament for treating infectious diseases.

[0039] The infectious diseases mentioned refer to those caused by drug-resistant bacteria, such as upper respiratory tract infections, pneumonia, cholecystitis, urinary tract infections, acute tonsillitis, bacterial dysentery, purulent meningitis, scarlet fever, tuberculosis, epidemic cerebrospinal meningitis, folliculitis, boils, etc.

[0040] The drug-resistant bacteria refer to methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli.

[0041] In a fourth aspect, the present invention provides the use of the baicalin derivative or its pharmaceutical salt in the preparation of an anti-inflammatory medicament.

[0042] The anti-inflammatory drugs mentioned refer to drugs used to treat leukemia.

[0043] In a fifth aspect, the present invention provides the use of the baicalin derivative or its pharmaceutical salt in the preparation of an antitumor medicament.

[0044] The tumor is selected from lung adenocarcinoma or intestinal cancer.

[0045] By adopting the above technical solution, the present invention has the following advantages and beneficial effects:

[0046] This invention optimizes the structure of baicalin to obtain a baicalin derivative. Through antibacterial activity tests on common Gram-positive bacteria such as drug-resistant Staphylococcus aureus and Gram-negative bacteria such as Escherichia coli and Klebsiella pneumoniae, it was found that this type of compound has excellent anti-drug-resistant bacterial activity and has great development value in the preparation of anti-infective therapeutic drugs.

[0047] The compounds of this invention are baicalin derivatives. Baicalin possesses anti-inflammatory, antioxidant, antitumor, and immunomodulatory activities (Zhang Qian et al., Journal of Yantai University: Natural Science and Engineering Edition, 2018, 3, 232-238; Fan Jinghui et al., Heilongjiang Medical Journal, 2015, 4, 783-784; Wang Lin et al., Tianjin Medical Journal, 2022, 4, 381-387). Therefore, the compounds of this invention can be used to prepare anti-inflammatory drugs, antitumor drugs, immunomodulatory drugs, and therapeutic agents for aging-related diseases. Detailed Implementation

[0048] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0049] Example 1

[0050] Preparation of compound I-1:

[0051]

[0052] Synthesis of 7-(2-bromoethoxy)-5-hydroxy-6-methoxy-2-phenyl-4H-benzopyran-4-one (3):

[0053] 5,7-Dihydroxy-6-methoxy-2-phenyl-4H-benzofuran-4-one (compound 1) (200 mg, 0.704 mmol) and anhydrous DMF (5 mL) were added to a 25 mL single-necked flask and stirred until homogeneous. Then, 1,3-dibromopropane (compound 2) (793 mg, 4.22 mmol) and potassium carbonate (243.3 mg, 1.76 mmol) were added, and the mixture was heated to 100 °C and reacted for 2 h. After the reaction was complete, the mixture was cooled to room temperature, filtered, and the solvent was removed by vacuum distillation. Water (50 mL) was added, and the mixture was extracted with ethyl acetate (20 mL × 3). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was removed by vacuum distillation. The mixture was purified by column chromatography to give compound 3 in 41% yield. 1HNMR(600MHz,Chloroform-d)δ12.73(s,1H),7.93–7.88(m,2H),7.61–7.52(m,3H), 6.69(s,1H),6.56(s,1H),4.45(t,J=6.2Hz,2H),3.97(s,3H),3.77(t,J=6.2Hz,2H).

[0054] Synthesis of (5-hydroxy-6-methoxy-4-oxo-2-phenyl-4H-chromene-7-oxy)ethyl)piperidin-4-ylcarbamate tert-butyl ester (5):

[0055] Compound 3 (91 mg, 0.233 mmol) and anhydrous DMF (2.5 mL) were added to a 10 mL single-necked flask. After stirring, 4-(Boc-amino)-piperidine (compound 4) (46.6 mg, 0.233 mmol) and potassium carbonate (80.5 mg, 0.583 mmol) were added, and the mixture was heated to 70 °C and reacted for 2 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the solvent was removed by vacuum distillation. After cooling, water (50 mL) was added, and the mixture was extracted with ethyl acetate (20 mL × 3). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was removed by vacuum distillation. The mixture was purified by column chromatography to give a white solid, compound 5, in 30.9% yield. 1 H NMR (600MHz, DMSO-d6) δ12.75(s,1H),8.13–8.07(m,2H),7.65–7.53(m,3H),7.03(d,J=3.5Hz,2H),4.29(s,2H),4.13(s ,1H),3.74(s,4H),3.31(d,J=69.1Hz,2H),3.13–2.93(m,1H),2.72(s,2H),1.73(m,2H),1.52–1.40(m,2H),1.36(s,9H).

[0056] Synthesis of 7-(2-(4-aminopiperidin-1-yl)ethoxy)-5-hydroxy-6-methoxy-2-phenyl-4H-benzopyran-4-one (6):

[0057] Compound 5 (100 mg, 0.244 mmol) was added to a 25 mL single-necked flask, followed by 3 mL of trifluoroacetic acid and 3 mL of dichloromethane. The mixture was reacted at room temperature for 2 h. After the reaction was complete, the solvent was removed by vacuum distillation to obtain compound 6, which can be used directly in the next reaction.

[0058] Synthesis of compound I-1:

[0059] Compound 6 (168 mg, 0.41 mmol) was added to a 10 mL single-necked flask, and 2.5 mL of anhydrous dichloroethane was added and stirred to dissolve it. Then, 4-bromo-3,5-difluorobenzaldehyde (90.5 mg, 0.41 mmol) and NaBH(OAC)3 (434.5 mg, 2.05 mmol) were added sequentially, and the reaction was carried out at room temperature for 2 h. After the reaction was completed, saturated sodium bicarbonate solution was added, and the mixture was extracted with dichloromethane (15 mL × 3). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and purified by column chromatography after removing the solvent under reduced pressure to obtain a yellow solid I-1 in 39.3% yield. 1 H NMR (600MHz, Methanol-d4) δ7.68 (dt, J=6.4, 1.3Hz, 2H), 7.38 (t, J=7.7Hz, 2H), 7.35–7.30(m,1H),7.17(d,J=8.2Hz,2H),6.26(s,1H),5.60(t,J=3.8Hz,1H),4.2 0(t,J=5.4Hz,2H),3.86(s,2H),3.79(s,3H),3.23(d,J=11.8Hz,2H),3.00(t,J= 5.5Hz,2H),2.66(s,1H),2.47–2.40(m,2H),2.01(s,2H),1.58(q,J=11.6Hz,2H). 13 CNMR(151MHz,MeOD)δ160.64,158.99,150.55,148.42,147.94,142.25,134.45,132.30,128.86,127.87,126.13,123 .92,111.70,100.85,95.45,92.86,65.91,60.03,56.43,53.11,52.20,48.51,30.34,19.14.HRMS(ESI,positive)m / z calcd for C 30 H 29 BrF₂N₂O₅[M+H] + :615.1306; found615.1301.

[0060] Example 2

[0061] Preparation of compound I-2:

[0062]

[0063] Following the preparation method of compound I-1 in Example 1, 3-fluoro-4-iodobenzaldehyde was used instead of 4-bromo-3,5-difluorobenzaldehyde to obtain a yellow solid with a yield of 3.8%. 1H NMR(600MHz,Chloroform-d)δ7.91–7.86(m,2H),7.70–7.65(m,1H),7.59–7.49(m,3 H),7.17–7.13(m,1H),6.94(d,J=8.0Hz,1H),6.67(s,1H),6.58(s,1H),4.27(t,J=5. 7Hz,2H),3.90(s,3H),3.83(s,2H),3.11–3.05(m,2H),2.97(t,J=5.7Hz,2H),2.63( d,J=11.4Hz,1H),2.32(t,J=11.4Hz,2H),2.03–1.97(m,2H),1.60(d,J=11.5Hz,2H). 13 C NMR (151MHz, CDCl3) δ182.70,164.03,162.57,160.94,157.90,153.19,142.06,139.27,132.82,131.89,131.22,129.11,126.27,125 .74,115.71,115.55,106.38,105.54,91.61,79.55,67.00,60.85,56.45,53.47,52.47,49.21,31.41,29.65.HRMS(ESI,positive)m / z calcd for C 30 H 30 FIN2O5[M+H] + : 645.1261; found 645.1256.

[0064] Example 3

[0065] Preparation of compound I-3:

[0066]

[0067] Following the preparation method of compound I-1 in Example 1, 4-chloro-3,5-difluorobenzaldehyde was substituted for 4-bromo-3,5-difluorobenzaldehyde to obtain a yellow solid with a yield of 3.8%. 1H NMR(600MHz,Methanol-d4)δ7.69–7.64(m,2H),7.39–7.35(m,2H),7.35–7.29(m,1H) ,7.18–7.15(m,2H),6.24(s,1H),5.58(t,J=3.8Hz,1H),4.14(t,J=5.6Hz,2H),3.79( s,2H),3.78(s,3H),3.14–3.08(m,2H),2.87(t,J=5.6Hz,2H),2.52(tt,J=10.7,4.0H z,1H),2.26(td,J=11.9,2.5Hz,2H),1.98–1.91(m,2H),1.51(qd,J=11.6,3.8Hz,2H). 13 C NMR(151MHz,MeOD)δ159.44,157.81,150.70,148.40,147.88,147.84,141.93, 134.46,132.26,128.85,127.88,127.80,123.93,111.61,111.44,107.16,100 .61,95.46,92.53,66.34,59.99,56.64,53.49,52.47,48.68,48.03,47.88,47 .74,47.60,47.46,47.32,47.17,31.02,29.38,19.17.HRMS(ESI,positive)m / z calcd forC 30 H 29 ClF₂N₂O₅[M+H] + : 571.1811; found 571.1806.

[0068] Example 4

[0069] Preparation of compound I-4:

[0070]

[0071] Following the preparation method of compound I-1 in Example 1, 4-bromobenzaldehyde was substituted for 4-bromo-3,5-difluorobenzaldehyde to obtain a yellow solid with a yield of 22.4%. 1H NMR(600MHz,Chloroform-d)δ7.93–7.88(m,2H),7.61–7.52(m,3H),7.50–7.4 3(m,2H),7.27–7.21(m,2H),6.70(s,1H),6.60(s,1H),4.26(t,J=5.9Hz,2H), 3.93(s,3H),3.80(s,2H),3.03(dd,J=11.9,4.0Hz,2H),2.92(t,J=5.9Hz,2H) ,2.59–2.51(m,1H),2.29–2.22(m,2H),1.97–1.91(m,2H),1.53–1.44(m,2H). 13 C NMR (151MHz, CDCl3) δ182.72,163.98,158.16,153.22,139.58,132.93,131.85,131.48,131.33,129.78,129.11,1 26.27,120.67,106.34,105.61,91.57,67.49,60.84,56.69,53.83,52.90,50.09,32.63.HRMS(ESI,positive)m / z calcd for C 30 H 31 BrN2O5[M+H] + : 579.1494; found 579.1489.

[0072] Example 5

[0073] Preparation of compound I-5:

[0074]

[0075] Following the preparation method of compound I-1 in Example 1, 4-iodobenzaldehyde was substituted for 4-bromo-3,5-difluorobenzaldehyde to obtain a yellow solid with a yield of 22.1%. 1H NMR(600MHz,Chloroform-d)δ7.93–7.88(m,2H),7.68–7.63(m,2H),7.61–7.51(m, 3H),7.14–7.08(m,2H),6.70(s,1H),6.60(s,1H),4.25(t,J=5.9Hz,2H),3.92(s,3H ),3.78(s,2H),3.05–2.99(m,2H),2.92(t,J=5.9Hz,2H),2.54(dq,J=10.2,5.0,4. 0Hz,1H),2.24(td,J=11.8,11.4,2.5Hz,2H),1.97–1.91(m,2H),1.54–1.44(m,2H). 13 C NMR (151MHz, CDCl3) δ182.71,163.98,158.12,153.24,140.19,137.45,132.89,131.84,131.30,130.08,129.09,126.25 ,106.32,105.58,92.13,91.55,67.40,60.83,56.66,53.77,52.87,50.75,50.13,32.55,30.58.HRMS(ESI,positive)m / z calcd forC 30 H 31 IN₂O₅[M+H] + : 627.1356; found 627.1350.

[0076] Example 6

[0077] Preparation of compound I-6:

[0078]

[0079] Following the preparation method of compound I-1 in Example 1, 3-fluoro-4-bromobenzaldehyde was used instead of 4-bromo-3,5-difluorobenzaldehyde to obtain a yellow solid with a yield of 17.5%. 1H NMR(600MHz,Chloroform-d)δ7.93–7.88(m,2H),7.60–7.52(m,3H),7.49(dd,J=8.2,7.1Hz, 1H),7.17(dd,J=9.5,1.9Hz,1H),7.02(dd,J=8.1,1.9Hz,1H),6.69(s,1H),6.59(s,1H),4.2 6(t,J=5.9Hz,2H),3.93(s,3H),3.81(s,2H),3.05–3.00(m,2H),2.92(t,J=5.9Hz,2H),2.53 (td,J=10.1,5.0Hz,1H),2.25(t,J=11.3Hz,2H),1.94(d,J=12.8Hz,2H),1.52–1.44(m,2H). 13 C NMR (151MHz, CDCl3) δ182.71,163.98,159.92,158.28,158.16,153.22,142.92,142.88,133.24,132.93,131.86,131.32,129.11,126.26,124. 66,124.64,116.01,115.86,106.97,106.83,106.34,105.60,91.57,67.50,60.83,56.69,53.85,52.89,49.76,32.71.HRMS(ESI,positive)m / z calcd forC 30 H 30 BrFN2O5[M+H] + : 597.1400; found 597.1395.

[0080] Example 7

[0081] Preparation of compound I-7:

[0082]

[0083] Following the preparation method of compound I-1 in Example 1, 4-bromo-3,5-difluorobenzaldehyde was replaced with 3,4-dihydro-2H-pyrano[2,3-C]pyridine-6-carboxaldehyde to obtain a yellow solid in 20% yield. 1H NMR(600MHz,Chloroform-d)δ8.09(s,1H),7.90(dt,J=6.8,1.6Hz,2H),7.60–7.51(m,3H),6.9 9(s,1H),6.68(s,1H),6.59(s,1H),4.23(dt,J=18.7,5.6Hz,4H),3.92(s,3H),3.83(s,2H),3. 05–2.99(m,2H),2.91(t,J=6.0Hz,2H),2.77(t,J=6.5Hz,2H),2.58(tt,J=10.3,4.0Hz,1H),2. 25(td,J=11.5,2.5Hz,2H),2.06–1.99(m,2H),1.99–1.93(m,2H),1.52(td,J=11.0,7.5Hz,2H). 13 CNMR(151MHz, CDCl3)δ182.71,163.97,158.17,153.25,153.18,150.86,150.51,138.57,132.90,131.84,131.30,131.04,129.10,126.2 6,122.72,106.31,105.57,91.56,67.42,66.55,60.84,56.65,54.35,52.89,51.58,45.38,32.47,24.22,21.67.HRMS(ESI,positive)m / z calcd for C 32 H 35 N3O6[M+H] + : 558.2604; found 558.2599.

[0084] Example 8

[0085] Preparation of compound I-8:

[0086]

[0087] Following the preparation method of compound I-1 in Example 1, 4-(Boc-amino)-3-hydroxypiperidine was substituted for trans-4-(Boc-amino)-piperidine to obtain a yellow solid with a yield of 20.0%. 1H NMR(600MHz,Chloroform-d)δ7.92–7.85(m,2H),7.59–7.51(m,3H),7.02–6.96(m,2H),6.68( s,1H),6.57(s,1H),4.27–4.20(m,2H),3.94(d,J=3.4Hz,1H),3.91(s,3H),3.74(d,J=14.1Hz, 1H),3.54(td,J=9.0,4.3Hz,1H),3.25–3.17(m,1H),3.05–2.93(m,3H),2.43–2.37(m,1H),2.2 9(ddd,J=11.2,9.6,2.7Hz,1H),2.20(t,J=10.1Hz,1H),2.09–2.02(m,1H),1.47–1.38(m,1H). 13 C NMR (151MHz, CDCl3) δ182.71,164.02,160.78,159.13,158.04,153.25,142.81,132.94,131.86,131.32,129.11,126.27,111 .18,106.41,105.64,91.60,70.68,67.27,60.84,60.66,58.82,56.26,52.58,49.65,29.68,29.64.HRMS(ESI,positive)m / z calcd for C 30 H 29 BrF₂N₂O₆[M+H] + : 631.1255; found 631.1250.

[0088] Example 9

[0089] Preparation of compound I-9:

[0090]

[0091] Following the preparation method of compound I-1 in Example 1, 4-(Boc-amino)-3-hydroxypiperidine and 4-chloro-3,5-difluorobenzaldehyde were substituted for 4-(Boc-amino)-piperidine and 4-bromo-3,5-difluorobenzaldehyde, respectively, to obtain a yellow solid with a yield of 39.3%. 1HNMR(600MHz,Chloroform-d)δ7.94–7.86(m,2H),7.60–7.51(m,3H),7.03(d,J=7.6Hz,2H),6.69(s,1H), 6.57(s,1H),4.24(td,J=5.8,1.4Hz,2H),3.97–3.93(m,1H),3.92(s,3H),3.75(d,J=14.1Hz,1H),3.55(td ,J=9.0,4.3Hz,1H),3.25–3.20(m,1H),2.99(qd,J=14.5,13.3,9.6Hz,3H),2.41(td,J=9.8,9.3,4.2Hz,1 H),2.32(dd,J=12.6,9.8Hz,1H),2.22(t,J=10.1Hz,1H),2.10–2.04(m,1H),1.44(qd,J=11.0,4.0Hz,1H). 13 CNMR(151MHz,DMSO-d6)δ182.85,163.90,159.04,158.60,157.40,153.21,152.56,145.13,132.64,132.59,131.14,129.60,126.8 8,111.95,105.82,105.41,92.99,71.07,67.69,60.93,60.51,60.15,56.33,55.36,52.47,49.23,30.00.HRMS(ESI,positive)m / z calcdfor C 30 H 29 ClF₂N₂O₆[M+H] + : 587.1760; found 587.1755.

[0092] Example 10

[0093] Preparation of compound I-10:

[0094]

[0095] Following the preparation method of compound I-1 in Example 1, 4-(Boc-amino)-3-hydroxypiperidine and 4-bromo-3,5-difluorobenzaldehyde were replaced with trans-4-(Boc-amino)-3-hydroxypiperidine and 3,4-dihydro-2H-pyrano[2,3-C]pyridine-6-carboxaldehyde, respectively, to obtain a yellow solid with a yield of 14.7%. 1H NMR(600MHz,Chloroform-d)δ7.89–7.84(m,2H),7.52(dt,J=14.4,6.9Hz,3H),7.42(dq,J=4.3,2.0Hz,1H),7.05–6.97(m, 2H),6.87(d,J=8.3Hz,1H),6.64(s,1H),6.55(s,1H),5.32(s,1H),4.36(ddd,J=5.0,3.0,0.9Hz,1H),4.34–4.29(m,1H),4. 27(s,1H),4.23(s,3H),4.22–4.17(m,2H),3.99–3.93(m,1H),3.90(s,3H),3.33(s,1H),3.26(d,J=10.1Hz,1H),3.05(d,J= 11.5Hz,1H),2.99–2.88(m,2H),2.70–2.62(m,1H),2.20(t,J=11.9Hz,1H),2.12(t,J=10.7Hz,1H),2.01(d,J=30.8Hz,1H). 13 C NMR(151MHz,Chloroform-d)δ190.73,182.70,163.99,157.96,153.22,143.67,132.86,131.85,131.26,129.09,126.26,124.21,122.15,118.41,11 8.03,117.65,106.39,105.54,91.58,68.65,67.13,64.31,64.28,60.87,60.30,58.97,55.95,52.69,52.20,48.94,29.69.HRMS(ESI,positive)m / z calcd for C 32 H 34 N₂O₈[M+H] + : 575.2393; found 575.2388.

[0096] Example 11

[0097] In vitro antibacterial activity assay of compounds I-1 to I-10

[0098] The in vitro antibacterial activity of three strains—methicillin-resistant Staphylococcus aureus ATCC 33591 (MRSA), Klebsiella pneumoniae ATCC 10031, and Escherichia coli ATCC 25922—was tested using the micro-broth dilution method. The minimum inhibitory concentration (MIC) was determined using gepotidacin and baicalein as controls.

[0099] The experimental strains included Gram-positive bacteria: methicillin-resistant Staphylococcus aureus ATCC 33591 (MRSA); and Gram-negative bacteria: Klebsiella pneumoniae ATCC 10031 and Escherichia coli ATCC 25922.

[0100] The specific steps are as follows:

[0101] (1) Preparation of test compound and culture medium: The test compound was prepared as a 10 mg / mL DMSO stock solution, and the culture medium was prepared according to the manufacturer's instructions.

[0102] (2) Gradual dilution of the test compound

[0103] Two-fold dilution of the test compound solution: Aseptically, add 12.8 μL of the drug solution to well 1 of a 96-well plate, then add 27.2 μL of DMSO. Add 2-12 μL of DMSO to each of the 20 wells and mix thoroughly. Take 20 μL from the first well and add it to the second well, mixing thoroughly. Collect 20 μL from the second well and add it to the third well, repeating this process until the eleventh well. Collect 20 μL and discard it. From the twelfth well onwards, only 20 μL of DMSO is used for growth and control. Add 180 μL of sterile water to the next well and mix thoroughly. The control drug is prepared using the same method. Place 10 μL in each of the 96 sterile wells to prepare different concentrations of the test compound solution as samples.

[0104] (3) Preparation of test strains and MIC experiment

[0105] Agar plates containing a single fungus were mixed with 5 ml of sterile physiological saline, and the spectrophotometer transmittance was approximately 80%. MHB liquid medium was diluted to 1:200, and 90 μL of the bacterial suspension was mixed with 10 μL of the target compound solution in the medium. Results were incubated at 35°C for 16–20 hours and then interpreted. Dilutes of the same compound were recorded in wells 1 through 12 as follows: 32, 16, 8, 4, 2, 1, 0.5, 0.25, 0.125, 0.0625, 0.03125, and 0 μg / mL. Each dilution of the same compound was used as a parallel sample.

[0106] (4) Results reading and judgment:

[0107] Referring to the 2013 CLSI recommendations: the MIC value is the lowest visible antimicrobial concentration that can completely inhibit the growth of microorganisms in a test tube or microdilution well. If only microorganisms growing in the pores can be identified, the device can be used to help read and record the results of microdilution experiments. When determining the growth endpoint, compare the growth of microorganisms in microdilution wells or in vitro with those of non-antimicrobial agents. The test is valid if the growth control wells show acceptable growth conditions (2mm button-shaped precipitates or a mixture with a certain degree of turbidity).

[0108] Table 1. Minimum inhibitory concentrations of compounds I-1 to I-10 against three bacterial strains.

[0109]

[0110]

[0111] As shown in Table 1, baicalin exhibited weak activity against the three bacterial strains, while the structurally optimized compounds I-1, I-2, I-3, I-4, I-5, and I-6 showed enhanced antibacterial activity and selectivity against methicillin-resistant Staphylococcus aureus (MRSA) and Klebsiella pneumoniae. Compounds I-1 and I-3 showed comparable activity to Gepotidacin against MRSA. These results indicate that the compounds of this invention have the potential for developing anti-infective drugs.

[0112] Example 12

[0113] In vitro anti-inflammatory activity assays of some compounds of this invention

[0114] Mouse mononuclear macrophage leukemia cell line RAW264.7 (purchased from Wuhan Pronosei Life Sciences Co., Ltd.) was selected as the cell line for anti-inflammatory activity assay. The expression levels of inflammatory factors such as TNF-α and IL-6 were evaluated. The anti-inflammatory activity was assessed using an inflammation-related physiological index (IR) score, ranging from 0 to 100. The IR scoring method was as follows: Cell-only culture medium was used as the blank group. Lipopolysaccharide (LPS) was added to the blank group to induce the expression of inflammatory factors in cells that did not exhibit inflammation, creating the model group. The compound was added to the model group as the experimental group. Inflammation-related index levels were measured in each group, and the results were calculated using the formula: IR = (Inflammation-related index level in model group - Inflammation-related index level in experimental group) / (Inflammation-related index level in model group - Inflammation-related index level in blank group) × 100%. The IR calculation formula used enzyme-linked immunosorbent assay (ELISA) to quantitatively characterize the inflammation-related index levels by detecting absorbance.

[0115] The specific experimental method was as follows: RAW264.7 cells were cultured in DMEM medium until they reached the logarithmic growth phase. After cell counts, they were seeded into 96-well cell culture plates. Once the cells were fully adherent, the old medium was discarded. 0.5 μM and 1 μM solutions of the compound prepared with the medium, along with the positive control compound 8-hydroxypsoralen, were added to the 96-well plates, and the plates were incubated for 2 hours. Lipopolysaccharide (LPS) was then added to induce the secretion of inflammatory factors for 4 hours. The cell supernatant was collected, and the levels of inflammatory factors such as TNF-α and IL-6 were measured according to the instructions of the enzyme-linked immunosorbent assay (ELISA) kit.

[0116] Table 2 shows the inhibitory effect of some of the compounds in the examples on IL-6 in RAW264.7 cells (1 μM).

[0117]

[0118]

[0119] Table 3 shows the inhibitory effects of some of the compounds in the examples on TNF-α in RAW264.7 cells.

[0120]

[0121] As shown in Tables 2 and 3, the compounds of this invention exhibit good inhibitory effects on IL-6 and TNF-α in mouse mononuclear macrophage leukemia RAW264.7. For example, compounds I-2, I-3, I-8, and I-10 show better inhibitory activity against IL-6 than baicalin; compounds I-1, I-2, and I-3 all show certain inhibitory activity against TNF-α at concentrations of 0.5 μM and 1 μM, while the inhibitory activity of baicalin is almost non-existent. These results indicate that the compounds of this invention can also be used to prepare anti-inflammatory drugs.

[0122] Example 13

[0123] In vitro antitumor activity assay of the compounds of this invention

[0124] Tumor cell proliferation inhibition assays were performed on some of the compounds of this invention using the CCK-8 assay (e.g., *Pharmacological Research Methods for New Drugs*, edited by Lü Qiujun, 2007: 242-243). The cell lines used were A549 (human lung adenocarcinoma cells) and HCT-116 (human colon cancer cells), and the culture medium was DMEM + 10% FBS + double antibiotics.

[0125] In vitro activity assay: 4-5 × 10⁻⁵ mg / well of the solution was added to each well of a 96-well plate. 4100 μL of cell suspension per cell / mL was incubated at 37°C in a 5% CO2 incubator. After 24 h, 10 μL of sample solution was added to each well, with duplicate wells, and incubated at 37°C in a 5% CO2 incubator for 72 h. 20 μL of 5 mg / mL CCK-8 solution was added to each well, and after 4 h, 100 μL of dissolving buffer was added to each well. The wells were then incubated to dissolve the cells, and the OD value at 570 nm was measured using a multi-wavelength microplate reader. The inhibition rate (IR) and half-maximal inhibitory concentration (IC50) were calculated using Excel software. 50 ).

[0126] Calculate the inhibition rate (IR%) of cell growth by the drug using the following formula.

[0127]

[0128] The experimental results are shown in Table 4, where the sample refers to the compound prepared in the corresponding example.

[0129] Table 4 shows the in vitro antitumor activity of compounds in some examples.

[0130]

[0131] The above experimental results show that the compounds of the present invention have good antitumor activity and exhibit excellent activity against lung adenocarcinoma, colorectal cancer, and other cell lines. For example, except for compound I-2, the other compounds showed activity of several micromoles against the HCT-116 tumor cell line, while baicalin showed almost no activity. Therefore, the compounds of the present invention and their salts can be used to prepare antitumor drugs.

[0132] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A baicalein derivative or a pharmaceutically acceptable salt thereof, characterized by, The structure of the baicalein derivative is selected from one of the following structures: 。 2. Use of a baicalein derivative or a pharmaceutically acceptable salt thereof in the manufacture of an antibacterial medicament, characterized in that, The bacteria refer to methicillin-resistant Staphylococcus aureus and Klebsiella pneumoniae; the structure of the baicalein derivative is selected from one of the following structures: 。 3. Use of a baicalein derivative or a pharmaceutically acceptable salt thereof in the manufacture of an anti-inflammatory medicament, characterized in that, The structure of the baicalein derivative is selected from one of the following structures: 。 4. Use of the baicalein derivative or a pharmaceutically acceptable salt thereof according to claim 1 in the preparation of an antitumor drug.

5. Use of the baicalein derivative or a pharmaceutical salt thereof according to claim 4 in the manufacture of an antitumor agent, characterized in that, The tumor is selected from lung adenocarcinoma or intestinal cancer.

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