Biphenyl compound and application thereof in resisting clinical drug-resistant bacteria

Abstract

The invention relates to the technical field of medicines, in particular to a biphenyl compound and application thereof in resisting clinical drug-resistant bacteria. The biphenyl compound provided by the invention has a structure as shown in a formula I: # imgabs0 #, in the formula I, R1 is H, R2 is C (CH3) 3, and R3 is H; or R1 = C (CH3) 3, R2 = H, and R3 = C (CH3) 3. The biphenyl compound provided by the invention can effectively inhibit various clinical drug-resistant bacteria, and has great application potential.

Description

Technical Field

[0001] The present invention relates to the field of pharmaceutical technology, and particularly relates to a biphenyl compound and its application in anti-clinical drug-resistant bacteria. Background Art

[0002] The discovery of antibiotics has saved many lives. However, with the widespread use of antibiotics, drug-sensitive strains have gradually been eliminated, and drug-resistant strains have become an important source of clinical infections. Currently, common clinically Gram-positive drug-resistant bacteria include Methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium, etc. Taking MRSA as an example, some drug-resistant strains show multi-drug resistance and are insensitive to a variety of antibiotics. Therefore, it is necessary to research and develop drugs that can effectively inhibit the activity of clinical drug-resistant bacteria. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a biphenyl compound and its application in anti-clinical drug-resistant bacteria. The biphenyl compound provided by the present invention can effectively inhibit a variety of clinical drug-resistant bacteria and has great application potential.

[0004] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a biphenyl compound having the structure shown in Formula I:

[0006]

[0007] In Formula I, R1 = H, R2 = C(CH3)3, R3 = H;

[0008] Or, R1 = C(CH3)3, R2 = H, R3 = C(CH3)3.

[0009] The present invention provides a preparation method of the biphenyl compound described in the above solution, including the following steps:

[0010] Mix compound A, 3,5-dimethoxyphenylboronic acid, an inorganic base reagent, a palladium catalyst, an organic phosphine ligand, and an organic-aqueous mixed solvent, and carry out the Suzuki-Miyaura reaction to obtain intermediate C;

[0011]

[0012] Mix the intermediate C, an organic solvent, and BBr₃ for a demethylation reaction to obtain the biphenyl compound.

[0013] Preferably, the molar ratio of the compound A to 3,5 - dimethoxyphenylboronic acid is 1:(1 - 1.2).

[0014] Preferably, the inorganic base reagent includes one or more of K₂CO₃, Na₂CO₃, KOH, NaOH, Ba(OH)₂, and K₃PO₄; the molar ratio of the compound A to the inorganic base reagent is 1:(3 - 4).

[0015] Preferably, the palladium catalyst includes one or more of Pd(OAc)₂, Pd(PPh₃)₄, PdCl₂, PdCl₂(dppf), and Pd(PPh₃)₂Cl₂; the molar ratio of the compound A to the palladium catalyst is 1:(0.01 - 0.1);

[0016] The organic phosphine ligand includes one or more of PPh₃, P(tBu)₃, and PCy₃; the molar ratio of the compound A to the organic phosphine ligand is 1:(0.02 - 0.2).

[0017] Preferably, the temperature of the Suzuki - Miyaura reaction is 90 - 110 °C and the time is 10 - 15 h; the Suzuki - Miyaura reaction is carried out under the protection of an inert gas.

[0018] Preferably, the molar ratio of the intermediate C to BBr₃ is 1:(1.2 - 2).

[0019] Preferably, the demethylation reaction is carried out under ice - bath conditions, and the reaction time is 10 min - 4 h.

[0020] The present invention provides the use of the biphenyl compound described in the above - mentioned scheme in the preparation of anti - clinical drug - resistant bacteria drugs.

[0021] Preferably, the clinical drug - resistant bacteria include one or more of methicillin - resistant Staphylococcus aureus, clinically drug - resistant Staphylococcus epidermidis, clinically drug - resistant Enterococcus faecalis, and clinically drug - resistant Enterococcus faecium.

[0022] The present invention provides a biphenyl compound. The two hydroxyl groups at the 3,5 - positions on the benzene ring and the hydrophobic alkyl group at the para - or meta - position on the other benzene ring endow the biphenyl compound with good antibacterial activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the preparation flow chart of Compound 1 and Compound 2;

[0024] Figure 2 for Compound 1 1HNMR spectrum;

[0025] Figure 3 is for Compound 1 13 C NMR spectrum;

[0026] Figure 4 is for Compound 2 1 HNMR spectrum;

[0027] Figure 5 is for Compound 2 13 C NMR spectrum. Detailed implementation mode

[0028] The present invention provides a biphenyl compound having the structure shown in Formula I:

[0029]

[0030] In Formula I, R1 = H, R2 = C(CH3)3, R3 = H;

[0031] Or, R1 = C(CH3)3, R2 = H, R3 = C(CH3)3.

[0032] The present invention provides a preparation method of the biphenyl compound described in the above scheme, including the following steps:

[0033] Mix Compound A, 3,5-dimethoxyphenylboronic acid, an inorganic base reagent, a palladium catalyst, an organic phosphine ligand and an organic-aqueous mixed solvent, and carry out the Suzuki-Miyaura reaction to obtain Intermediate C;

[0034]

[0035] Mix the Intermediate C, an organic solvent and BBr3, and carry out a demethylation reaction to obtain the biphenyl compound.

[0036] In the present invention, unless otherwise specified, the raw materials used are all commercially available products well-known in the art.

[0037] The present invention mixes Compound A, 3,5-dimethoxyphenylboronic acid, an inorganic base reagent, a palladium catalyst, an organic phosphine ligand and an organic-aqueous mixed solvent, and carries out the Suzuki-Miyaura reaction to obtain Intermediate C.

[0038] In the present invention, the molar ratio of Compound A to 3,5-dimethoxyphenylboronic acid is preferably 1:(1 - 1.2), and in specific embodiments, it can be 1:1, 1:1.1 or 1:1.2.

[0039] In the present invention, the inorganic basic reagent preferably includes one or more of K2CO3, Na2CO3, KOH, NaOH, Ba(OH)2 and K3PO4; the molar ratio of the compound A to the inorganic basic reagent is preferably 1:(3-4), and in specific embodiments, it can be 1:3, 1:3.5 or 1:4. In the present invention, the role of the inorganic basic reagent is to provide a basic environment, neutralize the generated HBr during the reaction, and reduce divalent palladium to zero-valent palladium.

[0040] In the present invention, the palladium catalyst preferably includes one or more of Pd(OAc)2, Pd(PPh3)4, PdCl2, PdCl2(dppf) and Pd(PPh3)2Cl2; the molar ratio of the compound A to the palladium catalyst is preferably 1:(0.01-0.1), and in specific embodiments, it can be 1:0.01, 1:0.05 or 1:0.1.

[0041] In the present invention, the organic phosphine ligand preferably includes one or more of PPh3, P(tBu)3 and PCy3; the molar ratio of the compound A to the organic phosphine ligand is preferably 1:(0.02-0.2), and in specific embodiments, it can be 1:0.02, 1:0.05, 1:0.1, 1:0.15 or 1:0.2. In the present invention, the organic phosphine ligand coordinates with palladium to form a stable complex, preventing metal aggregation or deactivation.

[0042] In the present invention, the organic-aqueous mixed solvent is preferably a mixture of an organic solvent and water; wherein, the organic solvent is preferably 1,4-dioxane, dimethyl sulfoxide or N,N-dimethylformamide; the volume ratio of the organic solvent to water is preferably 4:1. The present invention has no special requirements for the amount of the organic-aqueous mixed solvent, as long as it can ensure the smooth progress of the Suzuki-Miyaura reaction.

[0043] In the present invention, the mixing of the compound A, 3,5-dimethoxyphenylboronic acid, inorganic basic reagent, palladium catalyst, organic phosphine ligand and organic-aqueous mixed solvent preferably includes: first placing the compound A, 3,5-dimethoxyphenylboronic acid, inorganic basic reagent, palladium catalyst and organic phosphine ligand in a reaction vessel, then evacuating three times and replacing the air in the reaction vessel with an inert gas, sealing, and adding the organic-aqueous mixed solvent in an inert atmosphere.

[0044] In the present invention, the temperature of the Suzuki-Miyaura reaction is preferably 90-110 °C, and the time is preferably 10-15 h; in specific embodiments, the temperature of the Suzuki-Miyaura reaction can be 90 °C, 100 °C or 110 °C, and the time of the Suzuki-Miyaura reaction can be 10 h, 11 h, 12 h, 13 h, 14 h or 15 h. The Suzuki-Miyaura reaction of the present invention is preferably carried out under the protection of an inert gas. The present invention has no special requirements for the type of the inert gas, and any inert gas well-known in the art can be used, such as nitrogen and argon. In the present invention, the Suzuki-Miyaura reaction is preferably carried out under oil bath and stirring conditions.

[0045] After completing the Suzuki-Miyaura reaction, water is added to the obtained reaction system in the present invention to dilute the reaction solution, the organic solvent is removed by rotary evaporation under reduced pressure, the mixture is extracted three times with ethyl acetate, the organic phases are combined, washed with saturated brine, dried with anhydrous Na2SO4 for 4 h, and the ethyl acetate is removed by rotary evaporation under reduced pressure, and then purified by silica gel column chromatography to obtain intermediate C. In the present invention, the eluent used in the silica gel column chromatography is preferably petroleum ether and dichloromethane; the volume ratio of the petroleum ether to the dichloromethane is preferably 20:1.

[0046] After obtaining intermediate C, the present invention mixes the intermediate C, an organic solvent and BBr3 to carry out a demethylation reaction to obtain the biphenyl compound.

[0047] In the present invention, the molar ratio of the intermediate C to BBr3 is preferably 1:(1.2-2), and in specific embodiments, it can be 1:1.2, 1:1.4, 1:1.6, 1:1.8 or 1:2. In the present invention, the organic solvent preferably includes dichloromethane, carbon tetrachloride, n-pentane or carbon disulfide. The present invention does not make special limitations on the dosage of the organic solvent, and it is only necessary to ensure the smooth progress of the demethylation reaction.

[0048] In the present invention, the demethylation reaction is preferably carried out under ice bath conditions; the time of the demethylation reaction is preferably 10 min-4 h, and in specific embodiments, it can be 10 min, 30 min, 1 h, 2 h, 3 h or 4 h.

[0049] After the demethylation reaction is completed, the present invention slowly drops a pre-cooled 3M NaOH solution into the reaction system to quench the reaction. After the reaction solution returns to room temperature, the pH is adjusted to less than 4 with dilute hydrochloric acid. The organic solvent is removed by rotary evaporation under reduced pressure, diluted with water, extracted three times with ethyl acetate, the organic phases are combined, dried over anhydrous Na2SO4, and the ethyl acetate is removed by rotary evaporation under reduced pressure. The biphenyl compound is obtained by silica gel column chromatography purification. In the present invention, the eluent used in the silica gel column chromatography is preferably petroleum ether and ethyl acetate; the volume ratio of the petroleum ether to the ethyl acetate is preferably 4:1.

[0050] The present invention provides the use of the biphenyl compound described in the above solution in the preparation of anti-clinical drug-resistant bacteria drugs.

[0051] In the present invention, the clinical drug-resistant bacteria preferably include one or more of methicillin-resistant Staphylococcus aureus, clinically drug-resistant Staphylococcus epidermidis, clinically drug-resistant Enterococcus faecalis, and clinically drug-resistant Enterococcus faecium.

[0052] The following examples are used to illustrate in detail the biphenyl compound, its preparation method and application provided by the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0053] Example 1

[0054] The preparation methods of Compound 1 and Compound 2 are as follows, and the preparation process is as Figure 1 shown:

[0055] (1) Synthesis of intermediates C1 and C2: Substituted bromobenzenes (A1 and A2), 3,5-dimethoxyphenylboronic acid (B), potassium carbonate, palladium acetate and triphenylphosphine are added to a two-necked round-bottom flask in a molar ratio of 1:1.2:4:0.01:0.02. Connect the condenser, evacuate and replace the air in the round-bottom flask with argon three times. Then, an appropriate amount of a mixed solution of 1,4-dioxane and water with a volume ratio of 4:1 is added using a syringe, and the mixture is stirred and reacted in an oil bath at 90 °C for 12 h. After the reaction is completed, the reaction solution is diluted with water, the 1,4-dioxane is removed by rotary evaporation under reduced pressure, extracted three times with ethyl acetate, the organic phases are combined, washed with saturated brine, dried over anhydrous Na2SO4 for 4 h, and the ethyl acetate is removed by rotary evaporation under reduced pressure. Then, silica gel column chromatography purification is carried out (the eluent is petroleum ether and dichloromethane, and the volume ratio of petroleum ether to dichloromethane is 20:1 ) to obtain intermediates C1 and C2.

[0056] (2) Synthesis of target products 1 and 2: BBr3 is slowly dropped into the dichloromethane solutions of intermediates C1 and C2 respectively under an ice bath (the molar ratio of intermediates C1 and C2 to BBr3 is 1:1.4 ), React for 4 h, and monitor the reaction progress by thin-layer chromatography. After the reaction is completed, slowly add pre-cooled 3 M NaOH solution dropwise in an ice bath to quench the reaction. After the reaction solution returns to room temperature, adjust the pH < 4 with dilute hydrochloric acid, remove dichloromethane by rotary evaporation under reduced pressure, dilute with water, extract three times with ethyl acetate, combine the organic phases, dry over anhydrous Na2SO4, remove ethyl acetate by rotary evaporation under reduced pressure, and purify by silica gel column chromatography (the eluent is petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is 4:1) to obtain the target compounds 1 and 2.

[0057] Structural characterization of target compounds 1 and 2

[0058] The synthesized biphenyl compounds 1 and 2 were subjected to NMR analysis and mass spectrometry analysis, and the results are as follows:

[0059] Compound 1: C 16 H 18 O2; white solid; yield: 76%; [M-H] - Theoretical value: 241.1229; measured value: 241.1220.

[0060] 1 H NMR (600 MHz, Acetone-d6) δ 8.28 (d, J = 1.8 Hz, 2H), 7.54 - 7.48 (m, 2H), 7.48 - 7.44 (m, 2H), 6.61 (d, J = 2.2 Hz, 2H), 6.35 (t, J = 2.2 Hz, 1H), 1.34 (s, 9H).

[0061] 13 C NMR (151 MHz, Acetone-d6) δ 159.80 (2×C), 150.99, 143.93, 139.16, 127.25 (2×C), 126.41 (2×C), 106.21 (2×C), 102.36, 35.02, 31.63 (3×C).

[0062] Compound 2: C 20 H 26 O2; white solid; yield: 84%; [M-H] - Theoretical value: 297.1855; measured value: 297.1876.

[0063] 1 H NMR (600 MHz, Acetone-d6) δ 8.27 (d, J = 0.8 Hz, 2H), 7.47 (t, J = 1.8 Hz, 1H), 7.40 (d, J = 1.8 Hz, 2H), 6.61 (d, J = 2.2 Hz, 2H), 6.36 (t, J = 2.2 Hz, 1H), 1.37 (s, 20H).

[0064] 13 C NMR (151 MHz, Acetone-d6) δ 159.69 (2×C), 151.67 (2×C), 145.26, 141.54, 122.11, 121.97 (2×C), 106.59 (2×C), 102.21, 35.45 (2×C), 31.77 (6×C).

[0065] Figures 2 - 3 They are respectively the 1 1H NMR spectrum of Compound 1 and 13 13C NMR spectrum; Figures 4 - 5 They are respectively the 1 1H NMR spectrum of Compound 2 and 13 13C NMR spectrum.

[0066] From Figures 2 - 5 the above data, it can be seen that the target compound of the present invention has been successfully prepared.

[0067] Test of Biphenyl Compounds against Clinically Drug-Resistant Bacteria

[0068] The MIC detection of the biphenyl compounds of the present invention against different drug-resistant strains was carried out according to the standards formulated by the Clinical and Laboratory Standards Institute (CLSI) of the United States, and the microbroth dilution method was used for determination. The two-fold diluted drug solution (100 μL) and the bacterial solution (100 μL, about 1×10 6 CFU) were added to the 96-well plate by the liquid dilution method. After completion, it was placed in an incubator at 37 °C and 80% humidity and statically cultured for 16 - 24 h. Each experiment had 3 biological replicates. Penicillin, ceftaroline fosamil, oxacillin, levofloxacin, and ceftazidime were used as positive control drugs. The test results are shown in Tables 1 - 3.

[0069] Table 1 MIC (μg / mL) values of Compounds 1 and 2 against three strains of MRSA

[0070] Compound MRSA-1 MRSA-2 MRSA-3 Compound 1 20 20 20 Compound 2 2.5 2.5 2.5 Ceftaroline fosamil 32 32 64 Oxacillin 16 64 512

[0071] Note: In Table 1, MRSA-1, MRSA-2, and MRSA-3 represent three different strains of Methicillin-resistant Staphylococcus aureus, all of which were clinically isolated.

[0072] Table 2 MIC (μg / mL) values of Compounds 1 and 2 against Staphylococcus epidermidis

[0073] Compound Staphylococcus epidermidis Compound 1 20 Compound 2 5 Penicillin 64 Oxacillin 16

[0074] Table 3 MIC (μg / mL) values of Compounds 1 and 2 against Enterococcus faecalis and Enterococcus faecium

[0075] Compound Enterococcus faecalis Enterococcus faecium Compound 1 20 20 Compound 2 5 5 Penicillin 128 128 Levofloxacin 8 8

[0076] From the results in Tables 1 - 3, it can be seen that both Compounds 1 and 2 showed certain antibacterial activities. In particular, Compound 2 showed good inhibitory effects against three strains of MRSA, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium. The MIC values were less than those of the positive control drug, indicating its potential for development into an anti - clinically drug - resistant bacteria drug.

[0077] The above - mentioned is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A biphenyl compound, characterized in that It has the structure shown in formula I: In formula I, R1=H, R2=C(CH3)3, R3=H; Alternatively, R1=C(CH3)3, R2=H, R3=C(CH3)3.

2. The method for preparing the biphenyl compound according to claim 1, characterized in that: The following steps are involved: Compound A, 3,5-dimethoxyphenylboronic acid, an inorganic alkaline reagent, a palladium catalyst, an organic phosphine ligand and an organic-water mixed solvent are mixed to perform a Suzuki-Miyaura reaction to obtain an intermediate C; The intermediate C, an organic solvent and BBr3 are mixed and subjected to a demethylation reaction to obtain the biphenyl compound.

3. The preparation method according to claim 2, characterized in that: The molar ratio of the compound A to 3,5-dimethoxyphenylboronic acid is 1:(1-1.2).

4. The preparation method according to claim 2, characterized in that: The inorganic alkaline reagent includes one or more of K2CO3, Na2CO3, KOH, NaOH, Ba(OH)2 and K3PO4; the molar ratio of the compound A to the inorganic alkaline reagent is 1:(3-4).

5. The preparation method according to claim 2, characterized in that: The palladium catalyst includes one or more of Pd(OAc)2, Pd(PPh3)4, PdCl2, PdCl2(dppf) and Pd(PPh3)2Cl2; the molar ratio of the compound A to the palladium catalyst is 1:(0.01-0.1); The organic phosphine ligand includes one or more of PPh3, P(tBu)3 and PCy3; the molar ratio of the compound A to the organic phosphine ligand is 1:(0.02-0.2).

6. The preparation method according to any one of claims 2 to 5, characterized in that: The temperature of the Suzuki-Miyaura reaction is 90-110° C., and the time is 10-15 hours; the Suzuki-Miyaura reaction is carried out under the protection of an inert gas.

7. The preparation method according to claim 2, characterized in that: The molar ratio of the intermediate C to BBr3 is 1:(1.2-2).

8. The preparation method according to claim 2 or 7, characterized in that: The demethylation reaction is carried out in an ice bath, and the reaction time is 10 min to 4 h.

9. Use of the biphenyl compound according to claim 1 in the preparation of drugs against clinical drug-resistant bacteria.

10. The use according to claim 9, characterized in that: The clinical drug-resistant bacteria include one or more of methicillin-resistant Staphylococcus aureus, clinical drug-resistant Staphylococcus epidermidis, clinical drug-resistant Enterococcus faecalis and clinical drug-resistant Enterococcus faecium.

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