Antibacterial compounds and uses and methods of preparation

Abstract

The application discloses an antibacterial compound and application and a preparation method, and is characterized by a structural formula: on the basis of the research on the anti-infective drug cefovecin sodium for pets, the 3-position tetrahydrofuran ring structure of cefovecin sodium is retained, the 7-position side chain thereof is selected to be modified, the antibacterial activity and the antibacterial spectrum of cefovecin sodium are changed by introducing the side chain, and the antibacterial effect on staphylococcus is the best, and a new antibiotic product with clinical value is obtained.

Description

Technical Field

[0001] This invention relates to the field of biomedicine, specifically to an antibacterial compound, its application, and a preparation method. Background Technology

[0002] Antimicrobial agents (including antibiotics, antiviral drugs, antifungal drugs, and antiparasitic drugs) are medications used to prevent and treat infections in humans, animals, and plants. Antimicrobial resistance occurs when bacteria, viruses, fungi, and parasites change over time and no longer respond to drugs. Antimicrobial resistance leads to increasingly more difficult-to-treat infections. The misuse and overuse of antimicrobial agents are major drivers of the development of drug-resistant pathogens.

[0003] Antimicrobial resistance occurs when bacteria, viruses, fungi, and parasites cease to respond to antimicrobial drugs. Because drug resistance renders antibiotics and other antimicrobial treatments ineffective, treating infections becomes more difficult, and may even become impossible. This can lead to the emergence of superbugs, bacteria that are not inhibited by the first-line drugs used to treat these pathogens, thus increasing the risk of disease transmission, disability, and death. This problem is considered one of the top ten global public health threats.

[0004] In recent years, the widespread use, especially the overuse, of antibiotics has led to severe resistance in many pathogens to clinical antibiotics, particularly Gram-negative bacteria, which has become a serious threat to public health. However, the development of new antibiotics targeting Gram-negative resistant bacteria has been slow. Therefore, the search for new antibiotics and novel antibacterial strategies to address the global "antibiotic crisis" is urgently needed.

[0005] Cefavirenz sodium is a novel third-generation cephalosporin antibiotic specifically for animals. Its structural feature is the addition of a tetrahydrofuran heterocycle linked to the C-position of the cephalosporin nucleus via a C-C bond, thus endowing the product with broad-spectrum antibacterial activity and stability against β-lactamases. As an antibacterial agent, cefavirenz sodium exhibits a broad antibacterial spectrum and advantages in dogs and cats, including rapid absorption, slow elimination, high bioavailability, good safety profile, and a high therapeutic index. It is an ideal long-acting antibiotic for dogs and cats and has shown promising applications in veterinary clinical practice. It is primarily used to treat skin, digestive tract, genitourinary tract, bone, and soft tissue infections in dogs and cats caused by susceptible bacteria, as well as pyoderma in dogs caused by Staphylococcus aureus carrying the mecA gene. It can also be used to prevent postoperative infections in dogs and cats after surgery.

[0006]

[0007] The number of cephalosporin derivatives containing tetrahydrofuran heterocyclic compounds at the C-3 position reported in the literature is limited, and apart from cefotaxime, there is no further research and development of new derivatives with similar structures. Summary of the Invention

[0008] To address the aforementioned technical problems, the first objective of this invention is to provide an antibacterial compound, the second objective is to provide a method for its preparation, and the third objective is to provide its application.

[0009] To achieve the first objective mentioned above, the present invention provides the following technical solution: an antibacterial compound, characterized in that it has the following structural formula: .

[0010] The second objective of this invention is achieved as follows: a method for preparing an antibacterial compound, characterized in that (6R,7R)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-7-(2-(thiophen-2-yl)acetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid is prepared by: adding (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid, dichloromethane, and water to a reaction vessel, stirring and cooling to 0°C~5°C, and then adding NaOH dropwise. The solid was completely dissolved in a solution, and the pH was controlled at 8. 2-(thiophen-2-yl)acetyl chloride was added dropwise, and the pH was controlled at 8. After the addition was complete, the reaction was carried out at 0℃~5℃, while maintaining the pH at 8. After the reaction was complete, the mixture was allowed to stand and separated. The dichloromethane phase was concentrated under reduced pressure until dry, and then water was added. The mixture was filtered, and the filter cake was washed with water to purify the product.

[0011] In the above scheme, purification is performed using reversed-phase rapid chromatography. To obtain an ester or salt, it is simply a matter of preparing a sodium salt or undergoing an esterification reaction using existing techniques.

[0012] The use of the antimicrobial compound in the preparation of medicines for treating diseases in humans and animals caused by bacteria, viruses, fungi and parasites.

[0013] In the above scheme: the bacteria are Gram-negative or Gram-positive bacteria.

[0014] In the above scheme, the bacteria is Staphylococcus aureus. It also shows good antibacterial effects against Klebsiella pneumoniae and Pseudomonas aeruginosa.

[0015] Beneficial effects

[0016] This invention is based on the research of cefotaxime sodium, an anti-infective drug for pets. It retains the tetrahydrofuran ring structure at the 3-position and modifies the side chain at the 7-position. By introducing the side chain of this structure, the antibacterial activity and antibacterial spectrum of cefotaxime sodium are changed, especially the activity against common drug-resistant bacteria in clinical practice is improved. It shows good bactericidal activity against Staphylococcus aureus, thus obtaining a new antibiotic product with clinical value. Attached Figure Description

[0017] Figure 1 The distribution of MIC values ​​for the three existing drugs against Escherichia coli is shown.

[0018] Figure 2 Distribution of MIC values ​​of Escherichia coli against six tested compounds.

[0019] Figure 3 The distribution of MIC values ​​of Escherichia coli against 15 tested compounds is shown.

[0020] Figure 4 The distribution of MIC values ​​of the three drugs against Staphylococcus aureus.

[0021] Figure 5 The distribution of MIC values ​​of the eight tested compounds against Staphylococcus aureus is shown.

[0022] Figure 6 The distribution of MIC values ​​of 13 tested compounds against Staphylococcus aureus is shown. Detailed Implementation

[0023] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0024] Example 1

[0025] F50-001 Synthesis

[0026] 1. Chemical reaction formula

[0027]

[0028]

[0029] 2. Operating Procedures

[0030] first step:

[0031] Add 5.83 g of (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropyl-2-yl)oxy)imino)-2-(2-(((tert-butoxycarbonyl)amino)thiazolyl-4-yl)acetic acid and 150 mL of dichloromethane to a 250 mL three-necked flask, stir and cool to -20 °C under N2 atmosphere, add 1.56 g of methanesulfonyl chloride and 1.75 g of triethylamine, stir at -20 °C for 4 hours to obtain a mixed anhydride solution.

[0032] In a separate 500 mL three-necked flask, add 5.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester hydrochloride and 50 mL of dichloromethane. Cool to -20 °C under nitrogen protection, add 2.52 g of triethylamine, and stir for 10 minutes. Add the aforementioned mixed anhydride solution, and stir the reaction at -15 °C to -10 °C. Monitor the reaction by TLC (PE:EA = 1:3) until (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester is completely reacted. Add 200 mL of water, stir for 15 min, allow to stand and separate, and collect the dichloromethane phase. Concentrate under reduced pressure to obtain 12.63 g of crude product. Purify the crude product by silica gel column chromatography (EA:PE=0:100~EA:PE=75:25) to obtain 8.11 g of product.

[0033] Step Two:

[0034] 5.0 g of (6R,7R)-7-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropyl-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazo-4-yl)acetamido)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester) and 25 mL of dichloromethane were added to a 100 mL three-necked flask and stirred until dissolved at room temperature. Then, 25 mL of trifluoroacetic acid was added, and the reaction was stirred at room temperature for 24 hours, monitored by TLC. After the reaction was complete, the reaction solution was concentrated to dryness under reduced pressure to obtain the crude product. The crude product was purified by normal-phase silica gel column chromatography (MeOH:DCM=0:100~MeOH:DCM=20:80) to obtain 2.56 g of a pale yellow solid.

[0035] Step 3:

[0036] Add 1.0 g of (6R,7R)-7-((Z)-2-(((2-carbonyloxypropyl-2-yl)oxy)imino)-2-(2-(aminothiazol-4-yl)acetamido)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester and 7 mL of acetone to a 50 mL single-necked flask and stir until dissolved at room temperature. Add 5 mL of water, adjust the pH to 7-8 with ammonia, and then add 1.11 g of sodium dithionite. Stir the reaction mixture at room temperature for 1.5 hours. Monitor the reaction by TLC. After the reaction is complete, concentrate the reaction solution under reduced pressure to remove the acetone. The remaining solution is treated with 1 M... The pH was adjusted to 2 with HCl solution, resulting in the precipitation of a pale yellow solid. The precipitate was filtered to obtain the crude product. This crude product was purified by reversed-phase rapid chromatography under the following conditions: a C18 silica gel column; a mobile phase of acetonitrile-pure water in a gradient of 5% to 50% over 30 minutes; and a detection wavelength of 254 nm. The purified fraction was freeze-dried to obtain 260 mg of a white solid.

[0037] 1 H NMR (400 MHz, DMSO-d6) δ 10.87 (s, 1H), 7.21 (s, 2H), 6.73 (d, J =5.3 Hz, 1H), 5.64 (dt, J = 12.3, 5.8 Hz, 1H), 5.07 – 4.98 (m, 1H), 3.22 (dd, J = 27.7, 17.1 Hz, 2H), 2.12 – 2.00 (m, 1H), 1.82 (dddd, J = 23.1, 19.4, 9.1, 6.0 Hz, 2H), 1.66 –1.52 (m, 1H), 1.47 (d, J = 3.2 Hz, 3H), 1.40 (s, 3H).

[0038] LCMS (ESI(-)):524.0.

[0039] Example 2

[0040] F50-002 Synthesis

[0041] 1. Chemical reaction formula

[0042]

[0043]

[0044] 2. Operating Procedures

[0045] first step:

[0046] Add 80 mL of dichloromethane, 12 mL of ethanol, and 1.2 mL of water to a 250 mL three-necked flask, stir, and cool to 0-2 °C. Add 4.78 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and 8.0 g of S-2-benzothiazolyl-(Z)-2-(2-aminothiazolyl-4-yl)-2-methoxycarbonylmethoxyiminothioacetic acid ester. Add 3.0 mL of triethylamine dropwise at 0-5 °C and stir at the same temperature for 8-10 hours. Add 60 mL of water, stir for 5 minutes, let stand to separate the layers, add 60 mL of water to the organic layer, stir for 5 minutes, let stand to separate the layers, and combine the aqueous layers; add 1 g of activated carbon, 0.1 g of sodium hydrosulfite and 0.04 g of EDTA-2Na to the aqueous layer, concentrate under reduced pressure at 15~20℃ for 30 minutes, filter, wash with water, and combine the filtrates.

[0047] Step Two:

[0048] Cool to 0-2℃, add an aqueous solution of 60mL water and 2.48g sodium hydroxide pre-cooled to 0℃, stir for 10 minutes, and rapidly add 4% hydrochloric acid at 5-8℃ to adjust the pH to 5.0-5.5. Continue to adjust the pH to 1.9-2.0, cool to 0-5℃, stir for 30 minutes, filter, wash with water, and dry under reduced pressure at 35-40℃ for 6 hours to obtain 7.48g of (6R,7R)-7-((Z)-2-(2-aminothiazolyl-4-yl)-2-((carboxymethoxy)imine)acetamido)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, with a yield of 85%.

[0049] 1 H NMR (400 MHz, D2O)δ: 1.69-2.18(4 H,m),3.32 and 3.51(2H,ABq,J=18 Hz),3.74-3.93(2H,m),4.52(2H,s),5.19(1H,d,J=5 Hz),5.77(1H,d,J=5 Hz)and 7.01(IH,s).

[0050] LCMS (ESI(-)):495.9.

[0051] Example 3

[0052] F50-003 Synthesis

[0053] 1. Chemical reaction formula

[0054]

[0055] 2. Operating Procedures

[0056] In a 50 mL three-necked flask, add 1.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid, 1.76 g of S-(benzo[d]thiazol-2-yl)-2-(2-amino-5-chlorothiazol-4-yl)-2-(methoxyimino)ethyl thioester, 12 mL of tetrahydrofuran, and 3 mL of water, and stir at room temperature. Add dropwise a mixture of 0.56 g of triethylamine and 1 mL of tetrahydrofuran. Stir the reaction mixture at room temperature for 18 hours, and monitor the reaction by TLC.

[0057] After the reaction was complete, 6 mL of dichloromethane was added to the reaction system, stirred for 10 minutes, allowed to stand, and separated, retaining the aqueous phase. 12 mL of dichloromethane was added to the aqueous phase, stirred for 10 minutes, allowed to stand, and separated, retaining the aqueous phase and combining the organic phases. 18 mL of water was added to the organic phase, stirred for 10 minutes, allowed to stand, and separated, combining the aqueous phases. The pH of the aqueous phase was adjusted to 2 with 1M HCl, resulting in the precipitation of a large amount of solid. The mixture was stirred for 10 minutes, filtered, and the crude product was obtained.

[0058] The crude product was purified by reverse-phase rapid column chromatography under the following conditions: C18 silica gel column; acetonitrile-water mobile phase with a gradient of 5% to 50% over 30 minutes; detection wavelength 254 nm. The purified fraction was freeze-dried to obtain (6R, 7R)-7-{(Z)-2-[2-amino-5-chlorothiazo-4-yl]-2-(methoxyimino)propamido}-8-oxo-3-[(S)-tetrahydrofuran-2-yl]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (260 mg) as a white solid.

[0059] 1H NMR (400 MHz, DMSO-d6) δ 9.54 (dd, J = 9.8, 8.6 Hz, 1H), 7.41 (s,2H), 5.72 (td, J = 8.5, 4.8 Hz, 1H), 5.11 (dd, J = 7.6, 4.8 Hz, 1H), 4.73(dd, J = 8.9, 6.7 Hz, 1H), 3.86 (d, J = 1.4 Hz, 3H), 3.83 (d, J = 8.1 Hz,1H), 3.74 – 3.66 (m, 1H), 3.57 – 3.51 (m, 1H), 3.44 (s, 1H), 2.11 (dtd, J =10.5, 7.4, 5.3 Hz, 1H), 1.99 – 1.80 (m, 2H), 1.67 (ddq, J = 29.9, 12.0, 8.7Hz, 1H).

[0060] LCMS (ESI(-)): 486.0, 488.0.

[0061] Example 4

[0062] F50-004 Synthesis

[0063] 1. Chemical reaction formula

[0064]

[0065]

[0066]

[0067] 2. Operating Procedures

[0068] first step:

[0069] Add 3.74 g of (Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropyl-2-yl)oxy)imino)acetic acid, 25 mL of DMF, 4.73 g of HATU, and 4.39 g of N,N-diisopropylethylamine to a 50 mL single-necked flask. Stir at room temperature for 15 min, then add 5.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-4-nitrobenzyl ester hydrochloride. Stir at room temperature for 16 hours. Monitor the reaction by TLC.

[0070] After the reaction was complete, the reaction solution was poured into 100 mL of ethyl acetate, and 100 mL of water was added. The mixture was stirred for 10 min, allowed to stand, and separated. The organic phase was retained, and the aqueous phase was extracted twice with 50 mL of ethyl acetate. The combined organic phases were washed once with 100 mL of saturated brine and concentrated under reduced pressure until dry to give 9.33 g of a yellow crude solid. The crude product was purified by silica gel column chromatography using 0% to 75% ethyl acetate in petroleum ether as the eluent. The purified fraction was evaporated to dryness to obtain 7.16 g of (6R,7R)-7-((Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-((1-(tert-butoxy)-2-methyl-1-oxopropane-2-yl)oxyimino)acetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-4-nitrobenzyl ester, which was a white solid.

[0071] Step Two:

[0072] Add 4.0 g of (6R,7R)-7-((Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-((1-(tert-butoxy)-2-methyl-1-oxopropane-2-yl)oxyimino)acetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester and 40 mL of dichloromethane to a 250 mL single-necked flask. Stir until dissolved at room temperature, then add 40 mL of trifluoroacetic acid. Stir the reaction at room temperature for 16 hours and monitor the reaction by TLC.

[0073] After the reaction was complete, the product was concentrated to dryness under reduced pressure to obtain a brown oily substance. The crude product was purified by silica gel column chromatography using 0% to 10% methanol in dichloromethane as the eluent. The purified fraction was evaporated to dryness to obtain 2.7 g of (6R,7R)-7-((Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-((2-carboxypropane-2-yl)oxyimino)acetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester, which was a yellow solid.

[0074] Step 3:

[0075] Add 1.0 g of (6R,7R)-7-((Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-((2-carboxypropane-2-yl)oxyimino)acetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-4-nitrobenzyl ester and 7 mL of acetone to a 50 mL single-necked flask, stir until dissolved, then add 5 mL of water, adjust the pH to 8 with ammonia, add 3.74 g of sodium hydrosulfite, then add 2 mL of water, react at room temperature for 1.5 hours, and maintain the pH at 8 with ammonia. Monitor the reaction by TLC.

[0076] After the reaction was complete, the solution was concentrated under reduced pressure until acetone was completely removed. The pH was adjusted to 2 with 1M HCl solution, and a large amount of solid precipitated out. The solution was stirred for 10 minutes, filtered, and 0.8 g of crude yellow solid was obtained. The crude product was purified by reversed-phase rapid chromatography under the following conditions: C18 silica gel column; mobile phase was a mixture of acetonitrile and pure water, with a gradient change of 5% to 50% over 30 minutes; detection wavelength was 254 nm. The purified fraction was freeze-dried to obtain 120 mg of (6R,7R)-7-((Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(((2-carboxypropyl-2-yl)oxy)imino)acetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, which was a white solid.

[0077] 1 H NMR (400 MHz, DMSO-d6) δ 9.49 (t, J = 7.5 Hz, 1H), 8.20 (s, 2H), 5.78 (ddd, J = 10.4, 8.5, 4.8 Hz, 1H), 5.14 (dd, J = 6.5, 4.8 Hz, 1H), 4.75(dd, J = 8.9, 6.7 Hz, 1H), 3.85 (dq, J = 14.1, 7.2 Hz, 1H), 3.70 (td, J =7.8, 5.1 Hz, 1H), 3.58 – 3.49 (m, 2H), 2.10 (ddd, J = 11.8, 7.2, 4.1 Hz, 1H),1.90 (ddq, J = 28.0, 12.2, 5.7, 4.2 Hz, 2H), 1.67 (ddq, J = 26.5, 12.1, 8.6Hz, 1H), 1.47 (d, J = 2.4 Hz, 6H).

[0078] LCMS (ESI(-)):525.0.

[0079] Example 5

[0080] F50-012 Synthesis

[0081] 1. Chemical reaction formula

[0082]

[0083] 2. Operating Procedures

[0084] Add 30 mL of tetrahydrofuran and 30 mL of purified water to a 250 mL three-necked flask, cool to 0-5 °C, add 5.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid and 7.5 g of (Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(methoxyimino)thioacetic acid (S-2-benzothiazole) ester, and adjust the pH to 7.8-8.4 by adding a mixture of 2.9 mL of triethylamine and 4 mL of tetrahydrofuran dropwise at 0-5 °C, stirring for 5 hours. Add 50 mL of dichloromethane to the aqueous layer below 5 °C, stir for 5 minutes, and allow to separate into layers. Add 50 mL of dichloromethane to the aqueous layer, stir for 5 minutes, and allow to separate into layers. Combine the organic layers, add 15 mL of purified water, stir for 2 minutes, and allow to separate into layers. Combine the aqueous layers, adjust the pH to 2.6-3.0 by adding 15% hydrochloric acid dropwise at 0-10 °C, precipitate the solid, stir for 1 hour, filter, and wash with cold water. Dry under reduced pressure at 35-45 °C to obtain 4.0 g of product, with a yield of 85%.

[0085] 1 H NMR (400 MHz, DMSO-d6) δ 9.54 (t, J = 8.1 Hz, 1H), 8.12 (s, 2H), 5.73 (d, J = 5.4 Hz, 1H), 5.17 – 5.05 (m, 1H), 4.75 (t, J = 7.9 Hz, 1H), 3.91(d, J = 1.4 Hz, 3H), 3.83 (dt, J = 15.2, 7.2 Hz, 1H), 3.69 (d, J = 5.5 Hz,1H), 3.56 – 3.47 (m, 1H), 3.43 (s, 1H), 2.11 (d, J = 6.7 Hz, 1H), 1.97 – 1.77(m, 2H), 1.75 – 1.55 (m, 1H).

[0086] LCMS (ESI(-)):453.0.

[0087] Example 6

[0088] F50-013 Synthesis

[0089] 1. Chemical reaction formula

[0090]

[0091]

[0092] 2. Operating Procedures

[0093] first step:

[0094] Add 40 mL of tetrahydrofuran and 16 mL of water to a 250 mL three-necked flask, stir and cool to 15-20 °C, then add 4.78 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid and 7.2 g of [unclear text - possibly a typo, should be ... (Z)-2-(2-aminothiazol-4-yl)-2-acetoxyiminothioacetic acid (S-2-benzothiazolium) ester was added dropwise with a mixture of 2.64 mL triethylamine and 4 mL tetrahydrofuran, maintaining the pH of the reaction solution at 7.5–7.8. The reaction was carried out at 15–20 °C for approximately 4 hours. Then, 40 mL dichloromethane and 20 mL water were added, and the mixture was stirred for 5 minutes. The mixture was allowed to stand and separate into layers. The organic layer was washed once with 15 mL of water. The aqueous layers were combined, and the mixture was cooled to 10–15 °C. A solution of 2.8 g potassium carbonate and 12 mL water was added dropwise to adjust the pH to 8.0–8.5. Then, 2.7 g ammonium chloride was added, and simultaneously, an aqueous solution of potassium carbonate was added dropwise to adjust the pH to 8.0–8.5. The mixture was stirred for another 30 minutes. Finally, 8.2 g potassium acetate was added, bringing the pH to 9.0–9.5. The mixture was slowly cooled to approximately 0 °C, filtered, and washed with cold acetone. The wet product was weighed.

[0095] Step Two:

[0096] Add the wet product and 240 mL of purified water to the reaction flask, heat to 30-35℃, stir to dissolve, add 1.2 g of activated carbon and stir for 10 minutes, then filter; add 5% sulfuric acid dropwise at 30-35℃ to adjust the pH to 2.4-2.5, filter, wash with purified water, and dry under reduced pressure at 40-45℃ to obtain 5.8 g of product, with a yield of 75%.

[0097] 1H NMR (400 MHz, DMSO-d6) δ 13.42 (s, 1H), 11.29 (d, J = 3.1 Hz, 1H), 9.43 (t, J = 8.6 Hz, 1H), 7.12 (s, 2H), 6.67 (d, J = 8.0 Hz, 1H), 5.72 (ddd,J = 10.3, 8.1, 4.7 Hz, 1H), 5.13 (dd, J = 7.2, 4.7 Hz, 1H), 4.99 – 4.72 (m,1H), 3.85 (dq, J = 14.2, 7.2 Hz, 1H), 3.70 (tt, J = 7.9, 4.8 Hz, 1H), 3.55 –3.43 (m, 2H), 2.16 – 1.80 (m, 3H), 1.66 (ddq, J = 26.4, 12.1, 8.7 Hz, 1H).

[0098] LCMS (ESI(-)):438.0.

[0099] Example 7

[0100] F50-019 Synthesis

[0101] 1. Chemical reaction formula

[0102]

[0103]

[0104] 2. Operating Procedures

[0105] first step:

[0106] Add 30 mL of tetrahydrofuran to a 250 mL three-necked flask, cool to 0 °C, and add 2.32 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid and 5.0 g of (Z)-2-(2-aminothiazol-4-yl)-2-acetoxyiminothioacetic acid (S-2-benzothiazolium) ester while stirring. Add dropwise a mixture of 4.2 mL of triethylamine and 8 mL of tetrahydrofuran, control the pH of the reaction solution to 7.5-7.8, and react at 15-20 °C for about 48 hours. After concentration under reduced pressure, dissolve in ethyl acetate, wash with dilute hydrochloric acid aqueous solution, wash with brine, dry with anhydrous sodium sulfate, filter, concentrate under reduced pressure, and the obtained product can be directly used for the next reaction without purification.

[0107] Step Two:

[0108] Add 30 mL of dichloromethane and 8 mL of triethylsilane to the concentrated solution from the previous step, stir and cool to 0°C. Add 15 mL of trifluoroacetic acid, heat to room temperature and stir for 2 hours, concentrate under reduced pressure, disperse the residue with petroleum ether, filter, and dry to obtain 2.5 g of product.

[0109] 1 H NMR (400 MHz, DMSO-d6) δ 13.42 (s, 1H), 11.29 (d, J = 3.1 Hz, 1H), 9.43 (t, J = 8.6 Hz, 1H), 7.12 (s, 2H), 5.72 (ddd, J = 10.3, 8.1, 4.7 Hz,1H), 5.13 (dd, J = 7.2, 4.7 Hz, 1H), 4.99 – 4.72 (m, 1H), 3.85 (dq, J = 14.2,7.2 Hz, 1H), 3.70 (tt, J = 7.9, 4.8 Hz, 1H), 3.55 – 3.43 (m, 2H), 2.16 – 1.80(m, 3H), 1.66 (ddq, J = 26.4, 12.1, 8.7 Hz, 1H).

[0110] LCMS (ESI(-)):439.0.

[0111] Example 8

[0112] F50-035 Synthesis

[0113] 1. Chemical reaction formula

[0114]

[0115] 2. Operating Procedures

[0116] first step:

[0117] Add 50 mL of dichloromethane to a 250 mL three-necked flask, cool under nitrogen protection to below -20 °C, add 5.5 g of phosphorus pentachloride, and add 5.4 g of 2-ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetic acid while stirring. Stir at -15 to -12 °C for 30 minutes, then at -5 °C for 2 hours. Add 50 mL of isopropyl ether at -5 °C, and stir at -5 to 10 °C for 30 minutes. Filter, wash with isopropyl ether, and dry to obtain 6.02 g of 2-ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetyl chloride hydrochloride, yield 89.1%.

[0118] Step Two:

[0119] Add 2.7 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid and 50 mL of dichloromethane to a 100 mL reaction flask. Add 10 g of BSA (N,O-bistrimethylsilylacetamide) while stirring. Heat to 35 °C and stir until dissolved. Cool to -20 °C under nitrogen protection and add 2.8 g of... 2-Ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetyl chloride hydrochloride was stirred at -18 to -12°C for 25 minutes, then stirred at -12 to -3°C for 20 minutes. A solution of 4g sodium bicarbonate and 30mL water was added, and the mixture was allowed to stand to separate the aqueous layer. The pH of the aqueous layer was adjusted to 2.6 to 3.0 with 10% hydrochloric acid, and crystals precipitated. The crystals were filtered, washed with water, and dried to obtain 3.2g of the product.

[0120] 1 H NMR (400 MHz, DMSO-d6) δ 9.52 (t, J = 8.6 Hz, 1H), 8.13 (s, 2H), 5.74 (td, J = 9.5, 9.0, 4.7 Hz, 1H), 5.11 (dd, J = 7.1, 4.8 Hz, 1H), 4.75(dd, J = 8.9, 6.7 Hz, 1H), 4.17 (q, J = 7.1 Hz, 2H), 3.85 (dq, J = 14.7, 7.2Hz, 2H), 3.69 (td, J = 7.9, 5.3 Hz, 2H), 2.11 (dtd, J = 12.0, 7.3, 3.6 Hz,1H), 1.88 (dddd, J = 27.7, 17.1, 8.5, 4.7 Hz, 2H), 1.74 – 1.56 (m, 1H), 1.25(t, J = 7.0 Hz, 3H).

[0121] LCMS (ESI(-)):467.0.

[0122] Example 9

[0123] F50-057 Synthesis

[0124] 1. Chemical reaction formula

[0125]

[0126] 2. Operating Procedures

[0127] first step:

[0128] Add 40 mL of dichloromethane and 6.6 g of (Z)-2-(2-((tert-butoxycarbonyl)amino)thiazolyl-4-yl)pent-2-enoic acid to a 100 mL three-necked flask, stir, and cool to -20 °C under nitrogen protection. Add 2.43 g of methanesulfonyl chloride and 2.8 g of triethylamine dropwise, and continue the reaction for 3 hours to obtain a mixed acid anhydride for later use.

[0129] Step Two:

[0130] 5.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid was dissolved in a mixed solution of 30 mL methanol and 10 mL dichloromethane. The solution was cooled to -20 °C, and 4.12 g of TEA was added. The temperature was maintained at -20 °C, and a mixed acid anhydride solution was added dropwise. The reaction was carried out at 0-5 °C for 8-10 hours. After concentration under reduced pressure, ethyl acetate was added for dispersion, and the mixture was filtered and dried to obtain approximately 9.0 g of the product.

[0131] Step 3:

[0132] Take 500 mg of the dried product from the previous step (6R,7R)-7-((Z)-2-(2-((tert-butyloxycarbonyl)amino)thiazo-4-yl)pent-2-enamide)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid in a 50 mL single-necked flask, dissolve it in 1 mL of dichloromethane, add 1 mL of trifluoroacetic acid under ice bath, and stir for 1 hour. Dilute with 5 mL of dichloromethane, and a solid precipitates. Filter, wash the filter cake with dichloromethane, and dry to obtain 120 mg of white solid.

[0133] 1H NMR (400 MHz, DMSO-d6) δ 13.38 (s, 1H), 9.32 (dd, J = 7.9, 5.3 Hz,1H), 7.87 (s, 1H), 7.42 – 6.86 (m, 1H), 6.36 (d, J = 8.7 Hz, 1H), 6.25 (td, J= 7.7, 4.0 Hz, 1H), 5.73 (ddd, J = 23.5, 7.9, 4.7 Hz, 1H), 5.17 (dd, J = 7.1,4.7 Hz, 1H), 4.95 (s, 1H), 3.85 (dq, J = 14.5, 7.3 Hz, 1H), 3.72 (td, J =8.0, 4.6 Hz, 1H), 3.59 – 3.41 (m, 2H), 2.21 (m, J = 7.5, 4.2 Hz, 2H), 2.13 –1.96 (m, 1H), 1.94 – 1.77 (m, 2H), 1.76 – 1.60 (m, 1H), 1.02 (td, J = 7.5,1.7 Hz, 3H).

[0134] LCMS (ESI(-)):449.0.

[0135] Example 10

[0136] F50-093 Synthesis

[0137] 1. Chemical reaction formula

[0138]

[0139] 2. Operating Procedures

[0140] In a 50 mL three-necked flask, add 1.5 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid, 10 mL of dichloromethane, and 0.6 mL of water. Stir and cool to 0℃~5℃, then add 10% NaOH solution dropwise until the solid is completely dissolved, controlling the pH to 8. Add 0.98 g of 2-(thiophene-2-yl)acetyl chloride dropwise, controlling the pH to 8. After the addition is complete, react at 0℃~5℃ for 2 hours, maintaining the pH at 8, and monitor the reaction by TLC. After the reaction is complete, allow to stand and separate the liquids. Concentrate the dichloromethane phase under reduced pressure until dry, add 9 mL of water, filter, and wash the filter cake twice with water to obtain the crude product.

[0141] The crude product was purified by reversed-phase rapid chromatography under the following conditions: the column was a C18 silica gel column; the mobile phase was a mixture of acetonitrile and pure water, with a gradient change of 5% to 50% over 30 minutes; and the detection wavelength was 254 nm. The purified fraction was freeze-dried to obtain 210 mg of (6R,7R)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-7-(2-(thiophen-2-yl)acetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid, as a white solid.

[0142] 1 H NMR (400 MHz, DMSO-d6) δ 9.11 (d, J = 8.2 Hz, 1H), 7.36 (dd, J =5.1, 1.3 Hz, 1H), 6.97 – 6.90 (m, 2H), 5.63 (ddd, J = 15.2, 8.3, 4.7 Hz, 1H), 5.09 (dd, J = 9.0, 4.7 Hz, 1H), 4.74 (dd, J = 8.9, 6.7 Hz, 1H), 3.86 (m, J =7.6 Hz, 1H), 3.81 – 3.73 (m, 2H), 3.70 (dt, J = 7.9, 4.1 Hz, 1H), 3.59 – 3.40(m, 2H), 2.24 – 2.06 (m, 1H), 2.01 – 1.75 (m, 2H), 1.73 – 1.54 (m, 1H).

[0143] LCMS (ESI(-)):393.0.

[0144] Example 11

[0145] F50-95 Synthesis

[0146] 1. Chemical reaction formula

[0147]

[0148]

[0149] 2. Operating Procedures

[0150] first step:

[0151] Dissolve 2.1 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 30 mL of DMF, and then dissolve completely after adding 3.2 g of DIEA. Add 2.1 g of 2-cyanoacetic acid and 2.1 g of HATU, and stir at room temperature for 1 hour. Add water and ethyl acetate, stir, allow to stand for separation, concentrate the organic layer under reduced pressure, and purify by silica gel column chromatography to obtain 2 g of yellow solid.

[0152] Step Two:

[0153] Dissolve 1 g of (6R,7R)-7-(2-cyanoacetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 6 mL of acetone and stir until dissolved. Add 1.9 g of sodium dithionite in portions and adjust the pH to 7-8 with ammonia. Stir at room temperature for 1 hour. Monitor the reaction of the starting material by TLC until complete. Extract with dichloromethane, purify the aqueous phase by reversed-phase silica gel column chromatography, and lyophilize to obtain 0.2 g of pale yellow powder.

[0154] 1 H NMR (400 MHz, DMSO-d6) δ 13.43 (s, 1H), 9.28 (dd, J = 10.1, 8.2Hz, 1H), 5.64 (ddd, J = 15.4, 8.1, 4.7 Hz, 1H), 5.12 (dd, J = 9.6, 4.7 Hz,1H), 4.86 (ddd, J = 87.1, 8.6, 6.7 Hz, 1H), 3.91 – 3.82 (m, 1H), 3.78 (t, J =5.7 Hz, 2H), 3.74 – 3.68 (m, 1H), 3.62 – 3.52 (m, 1H), 3.46 (dd, J = 17.8,11.8 Hz, 1H), 2.19 – 1.89 (m, 2H), 1.89 – 1.56 (m, 2H).

[0155] LCMS (ESI(-)):336.0.

[0156] Example 12

[0157] F50-096 Synthesis

[0158] 1. Chemical reaction formula

[0159]

[0160]

[0161] 2. Operating Procedures

[0162] first step:

[0163] Dissolve 1.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 10 mL of DMF, add 1.6 g of DIEA, stir until dissolved, add 0.83 g of 2-(4-pyridinylthio)acetic acid, then add 1.03 g of HATU, and stir at room temperature for 1 hour. Monitor the reaction of the starting material by TLC plate until complete. Add water and ethyl acetate, stir, allow to stand for layering, concentrate the organic layer under reduced pressure, and purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate) to obtain 1 g of yellow solid.

[0164] Step Two:

[0165] Dissolve 1 g of (6R,7R)-8-oxo-7-(2-(4-pyridinylthio)acetamide)-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrophenyl ester in 6 mL of acetone and stir until dissolved. Add sodium dithionite in portions and adjust the pH to 7-8 with ammonia. Stir at room temperature for 1 hour, and monitor the reaction of the starting material by TLC until complete. Extract with dichloromethane, purify the aqueous phase by reverse-phase column chromatography, and lyophilize to obtain 0.2 g of a pale yellow powder.

[0166] 1 H NMR (400 MHz, DMSO-d6) δ 13.41 (s, 1H), 9.28 (t, J = 8.3 Hz, 1H), 8.63 – 8.23 ​​(m, 2H), 7.30 (dt, J = 4.6, 1.3 Hz, 2H), 5.65 (ddd, J = 15.4,8.3, 4.7 Hz, 1H), 5.10 (dd, J = 9.5, 4.7 Hz, 1H), 4.85 (ddd, J = 82.8, 8.6,6.7 Hz, 1H), 4.00 – 3.78 (m, 3H), 3.72 (tdd, J = 7.8, 5.4, ​​1.5 Hz, 1H), 3.51(qd, J = 17.5, 10.7 Hz, 2H), 2.21 – 1.89 (m, 2H), 1.89 – 1.58 (m, 2H).

[0167] LCMS (ESI(-)):420.0.

[0168] Example 13

[0169] F50-099 Synthesis

[0170] 1. Chemical reaction formula

[0171]

[0172] 2. Operating Procedures

[0173] first step:

[0174] Add 36.5 mL of dry dichloromethane to a 100 mL three-necked flask. Under a nitrogen atmosphere, add 5.16 g of phosphorus pentachloride, heat to 30 °C, and stir until most of the solid dissolves. Then cool to -25 °C and add 7.5 mL of dimethyl carbonate dropwise, controlling the temperature not to exceed -12 °C. After the addition is complete, stir at -25 °C for 30 minutes, then add 4.13 g of (Z)-2-(furan-2-yl)-2-(methoxyimino)acetic acid ammonium, and maintain the temperature at -15 to -12 °C with stirring for 1 hour. Then cool to -20 °C and stir for 30 minutes. Measure 18 mL of 2 °C water and slowly add it dropwise to the reaction system, controlling the temperature at 0 to 1 °C. After the addition is complete, maintain the temperature at 0 to 1 °C with stirring for 10 minutes, allow to stand, and separate the liquids. Wash the organic phase twice with 18 mL of 2 °C water. The organic phase was cooled to -5℃ for later use, yielding a (Z)-2-(furan-2-yl)-2-(methoxyimino)acetyl chloride solution.

[0175] Step Two:

[0176] Add 5.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid and 21.5 mL of water to a 250 mL three-necked flask. Cool to 0-2 °C and slowly add 10% NaOH solution until the solid is completely dissolved and the pH is 8, controlling the temperature not to exceed 5 °C. Add (Z)-2-(furan-2-yl)-2-(methoxyimino)acetyl chloride solution to the reaction system, controlling the temperature to -2-6 °C and the pH to 6.5-7.0. After the addition is complete, react for 2.5 hours. Monitor the reaction by HPLC. After the reaction is complete, allow to stand and separate the phases. Wash the organic phase once with 5 mL of cold water at 2 °C and combine the aqueous phases. Adjust the pH of the aqueous phase to 2 with 1 M HCl solution. A large amount of solid precipitates out and is filtered. 7.9 g of crude product is obtained.

[0177] Step 3:

[0178] 1.0 g of the crude product was purified by reversed-phase rapid chromatography under the following conditions: the column was C18 silica gel; the mobile phase was a mixture of acetonitrile and pure water, with a gradient change of 5% to 50% over 30 minutes; and the detection wavelength was 254 nm. The purified fraction was freeze-dried to obtain 400 mg of (6R,7R)-7-((Z)-2-(furan-2-yl)-2-(methoxyimino)acetamido)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, which was a white solid.

[0179] 1 H NMR (400 MHz, DMSO-d6) δ 9.75 (dd, J = 8.0, 5.9 Hz, 1H), 7.83 (d, J= 1.7 Hz, 1H), 6.74 – 6.61 (m, 2H), 5.71 (ddd, J = 15.3, 7.9, 4.7 Hz, 1H), 5.15 (dd, J = 7.5, 4.7 Hz, 1H), 5.04 – 4.74 (m, 1H), 3.89 (d, J = 1.8 Hz, 3H), 3.84 (dt, J = 14.3, 7.2 Hz, 1H), 3.70 (tt, J = 7.9, 4.2 Hz, 1H), 3.58 –3.52 (m, 1H), 3.44 – 3.38 (m, 1H), 2.16 – 2.06 (m, 1H), 2.00 – 1.78 (m, 2H), 1.65 (ddq, J = 26.4, 12.1, 8.6 Hz, 1H).

[0180] LCMS (ESI(-)):420.0.

[0181] Example 14

[0182] F50-100 Synthesis

[0183] 1. Chemical reaction formula

[0184]

[0185]

[0186] 2. Operating Procedures

[0187] first step:

[0188] Dissolve 3 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 50 mL of DCM, and add 2.25 g of TEA. Stir and cool to below -5 °C, then add 2.2 g of (R)-2-chloro-2-oxo-1-phenylethyl carboxylate, and stir at the same temperature for 30 minutes. After the reaction is complete as monitored by TLC, add water, allow to stand to separate the organic layer, dry with anhydrous sodium sulfate, filter, concentrate under reduced pressure, and purify by silica gel column chromatography (petroleum ether / ethyl acetate) to obtain 3.5 g of yellow solid.

[0189] Step Two:

[0190] Dissolve 1.0 g of (6R,7R)-7-((R)-2-(formyloxy)-2-phenylacetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 6 mL of acetone and stir until dissolved. Add water to the reaction solution, resulting in a pale yellow turbidity. Add 1.38 g of sodium dithionite in portions and adjust the pH to 7-8 with ammonia. Stir at room temperature for 1 hour. Monitor the reaction of the starting materials by TLC until complete. Extract with dichloromethane, retaining the aqueous phase. Adjust the pH of the aqueous phase to approximately 2 with hydrochloric acid, resulting in the precipitation of a solid. Filter the solid, purify the wet product by reverse-phase (pure water system), and lyophilize to obtain 0.2 g of a pale white solid.

[0191] 1 H NMR (400 MHz, DMSO-d6) δ 13.46 (s, 1H), 9.38 (dd, J = 10.4, 8.2 Hz,1H), 8.41 – 8.27 (m, 1H), 7.50 (h, J = 3.4 Hz, 2H), 7.39 (qd, J = 5.2, 4.2,1.9 Hz, 3H), 6.13 – 6.03 (m, 1H), 5.69 – 5.51 (m, 1H), 4.99 (dd, J = 7.9, 4.7Hz, 1H), 4.77 – 4.66 (m, 1H), 3.84 (tt, J = 14.3, 7.4 Hz, 1H), 3.73 – 3.64(m, 1H), 3.55 – 3.38 (m, 2H), 2.14 – 1.79 (m, 3H), 1.71 – 1.55 (m, 1H).

[0192] LCMS (ESI(-)):431.0.

[0193] Example 15

[0194] F50-101 Synthesis

[0195] 1. Chemical reaction formula

[0196]

[0197]

[0198] 2. Operating Procedures

[0199] first step:

[0200] Dissolve 3.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 50 mL of DMF, and then dissolve completely after adding 4.8 g of DIEA. Add 1.4 g of 2-(2-aminothiazol-4-yl)acetic acid and 3.4 g of HATU, stir at room temperature for 1 hour, monitor the reaction of the starting material by TLC until complete, add water, stir, extract with ethyl acetate, concentrate the organic layer under reduced pressure, and give 4 g of white solid.

[0201] Step Two:

[0202] Dissolve 1.0 g of (6R,7R)-7-(2-(2-aminothiazol-4-yl)acetamido)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 6 mL of acetone. Add 1.44 g of sodium dithionite in portions and adjust the pH to 7-8 with ammonia. Stir at room temperature for 1 hour. Monitor the reaction of the starting material by TLC until complete. Filter to remove a small amount of solid residue. Wash the filtrate with dichloromethane. Purify the aqueous phase by reverse-phase silica gel column chromatography (pure water system). Lyophilize to obtain 0.2 g of pale white solid.

[0203] 1H NMR (400 MHz, DMSO-d6) δ 8.87 (t, J = 7.8 Hz, 1H), 6.90 (d, J = 3.9Hz, 2H), 6.25 (d, J = 2.5 Hz, 1H), 5.63 (ddd, J = 13.1, 8.5, 4.7 Hz, 1H), 5.08 (dd, J = 9.0, 4.8 Hz, 1H), 4.76 (dd, J = 8.9, 6.7 Hz, 1H), 3.86 (m, J =7.1 Hz, 1H), 3.70 (td, J = 7.9, 5.3 Hz, 1H), 3.60 – 3.48 (m, 1H), 3.43 (d, J= 18.0 Hz, 1H), 3.38 (t, J = 2.9 Hz, 2H), 2.19 – 2.06 (m, 1H), 1.90 (ddtd, J= 35.2, 15.3, 7.4, 3.8 Hz, 2H), 1.66 (ddq, J = 30.0, 12.2, 8.7 Hz, 1H).

[0204] LCMS (ESI(-)):409.0.

[0205] Example 16

[0206] F50-103 Synthesis

[0207] 1. Chemical reaction formula

[0208]

[0209]

[0210] 2. Operating Procedures

[0211] first step:

[0212] Dissolve 2.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 35 mL of DMF, add 3.2 g of DIEA, and stir until dissolved. Add 2.0 g of (R)-2-(4-ethyl-2,3-dioxopiperazin-1-carboxamido)-2-(4-hydroxyphenyl)acetic acid and 2.25 g of HATU, and stir at room temperature for 1 hour. Monitor the reaction of the starting material by TLC until complete, and then stop the reaction. Add water and ethyl acetate, allow to stand, separate the organic layer, concentrate the organic layer under reduced pressure, and purify the residue by silica gel column chromatography in normal phase (petroleum ether / ethyl acetate) to give 2.8 g of pale yellow solid.

[0213] Step Two:

[0214] Dissolve 1.0 g of (6R,7R)-7-((R)-2-(4-ethyl-2,3-dioxopiperazin-1-carboxamido)-2-(4-hydroxyphenyl)acetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 6 mL of acetone and stir until dissolved. Add water to the reaction solution, add 1.9 g of sodium dithionite in portions, and adjust the pH to 7-8 with ammonia. Stir at room temperature for 1 hour, and monitor the reaction of the starting material by TLC until complete. Wash with dichloromethane, adjust the pH of the aqueous phase to about 2 with hydrochloric acid, and the solid precipitates. Filter, purify the wet product by reversed-phase column chromatography (pure water system), and lyophilize to obtain 0.15 g of pale white solid.

[0215] 1 H NMR (400 MHz, DMSO-d6) δ 9.77 – 9.62 (m, 2H), 9.25 (dd, J = 24.4,8.5 Hz, 1H), 7.21 (ddd, J = 9.6, 4.8, 2.4 Hz, 2H), 6.78 – 6.65 (m, 2H), 5.48(dd, J = 8.1, 5.7 Hz, 2H), 4.91 – 4.82 (m, 1H), 3.98 – 3.84 (m, 2H), 3.84 –3.73 (m, 1H), 3.70 – 3.51 (m, 3H), 3.44 – 3.37 (m, 2H), 3.31 – 3.08 (m, 2H), 2.10 (ddd, J = 24.1, 11.9, 6.1 Hz, 1H), 1.90 – 1.70 (m, 2H), 1.58 – 1.42 (m,1H), 1.08 (t, J = 7.2 Hz, 3H).

[0216] LCMS (ESI(-)):586.0.

[0217] Example 17

[0218] F50-105 Synthesis

[0219] 1. Chemical reaction formula

[0220]

[0221]

[0222] 2. Operating Procedures

[0223] first step:

[0224] Add 1.62 g of 2,6-dimethoxybenzoic acid and 100 mL of dichloromethane to a 250 mL three-necked flask, purging three times with N2, and stirring under N2 atmosphere to cool to -20 °C. Then add 1.02 g of methanesulfonyl chloride and 1.14 g of triethylamine, and stir at -20 °C for 4 hours to obtain a mixed anhydride solution for later use.

[0225] In a separate 250 mL three-necked flask, add 3.26 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester hydrochloride and 30 mL of dichloromethane. Cool to -20 °C, add 1.65 g of triethylamine, and stir for 15 minutes. Add the above mixed anhydride solution, and stir the reaction at -15 to -10 °C. Monitor the reaction by TLC (PE:EA = 1:3) until (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester is completely reacted. Add 130 mL of water, stir for 15 minutes, allow to stand and separate, and collect the dichloromethane phase. Concentrate the organic phase under reduced pressure to obtain 3.30 g of crude product. The crude product is purified by silica gel column chromatography (EA:PE=0:100~EA:PE=75:25) to obtain 2.66 g of white solid.

[0226] Step Two:

[0227] Add 1.0 g of (6R,7R)-7-(2,6-dimethoxybenzamide)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-4-nitrobenzyl ester and 7 mL of acetone to a 50 mL single-necked flask, stir until dissolved, then add 5 mL of water, adjust the pH to 8 with ammonia, add 1.29 g of sodium hydrosulfite, then add 2 mL of water, react at room temperature for 1.5 hours, and maintain the pH at 8 with ammonia. Monitor the reaction by TLC.

[0228] The reaction solution was concentrated under reduced pressure until acetone was completely removed. The pH was adjusted to 2 with 1M HCl solution, and a large amount of solid precipitated out. The mixture was stirred for 10 minutes and filtered to obtain 0.77g of crude yellow solid.

[0229] The crude product was purified by reversed-phase rapid chromatography under the following conditions: a C18 silica gel column; a mobile phase of acetonitrile in pure water, with a gradient change of 5% to 50% over 30 minutes; and a detection range of 254 nm. The purified fraction was freeze-dried to obtain 540 mg of (6R,7R)-7-(2,6-dimethoxyaniline)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, as a white solid.

[0230] 1 H NMR (400 MHz, DMSO-d6) δ 9.09 (dd, J = 11.7, 8.7 Hz, 1H), 7.39 –7.21 (m, 1H), 6.67 (d, J = 3.1 Hz, 1H), 6.65 (d, J = 3.0 Hz, 1H), 5.80 (td, J= 8.9, 4.8 Hz, 1H), 5.13 (dd, J = 6.7, 4.8 Hz, 1H), 4.81 – 4.72 (m, 1H), 3.87(q, J = 7.4 Hz, 1H), 3.73 (s, 6H), 3.70 (dd, J = 7.9, 5.3 Hz, 1H), 3.53 (d, J= 18.1 Hz, 1H), 3.48 – 3.39 (m, 1H), 2.11 (td, J = 11.9, 7.3 Hz, 1H), 1.89 (dtdd, J = 25.0, 20.1, 10.0, 5.4 Hz, 2H), 1.75 – 1.58 (m, 1H).

[0231] LCMS (ESI(-)):432.9.

[0232] Example 18

[0233] F50-106 Synthesis

[0234] 1. Chemical reaction formula

[0235]

[0236] 2. Operating Procedures

[0237] In a 50 mL three-necked flask, add 3.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid and 15 mL of water. Stir and cool to 0-5 °C, then add 10% NaOH solution dropwise until the solid is completely dissolved, maintaining pH 8. Slowly add 2.71 g of 5-methyl-3-phenylisoxazole-4-carbonyl chloride, maintaining pH 8. After the addition is complete, react at 0-5 °C for 2 hours, maintaining pH 8, and monitor the reaction by TLC. After the reaction is complete, adjust the pH of the reaction solution to 2 with 1 M HCl solution. The solid precipitates, is filtered, and the filter cake is washed twice with 5 mL of cold water at 2 °C, then dried to obtain 3.55 g of crude product.

[0238] 1.0 g of crude product was purified by reversed-phase rapid chromatography under the following conditions: C18 silica gel column; mobile phase was a mixture of acetonitrile and pure water, with a gradient change of 5% to 50% over 30 minutes; detection wavelength was 254 nm. The purified fraction was freeze-dried to obtain 350 mg of (6R,7R)-7-(5-methyl-3-phenylisoxazol-4-carboxamido)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid, as a white solid.

[0239] 1 H NMR (400 MHz, DMSO-d6) δ 9.50 (d, J = 8.0 Hz, 1H), 7.72 – 7.63 (m,2H), 7.54 – 7.45 (m, 3H), 5.78 (ddd, J = 23.1, 8.0, 4.7 Hz, 1H), 5.20 (dd, J = 8.8, 4.7 Hz, 1H), 4.88 (ddd, J = 93.1, 8.7, 6.7 Hz, 1H), 3.92 – 3.80 (m,1H), 3.71 (td, J = 7.9, 5.2 Hz, 1H), 3.61 – 3.45 (m, 2H), 2.57 (d, J = 4.3Hz, 3H), 2.16 – 2.06 (m, 1H), 2.01 – 1.78 (m, 2H), 1.76 – 1.56 (m, 1H).

[0240] LCMS (ESI(-)): 454.0

[0241] Example 19

[0242] F50-107 synthesis

[0243] 1. Chemical reaction formula

[0244]

[0245] 2. Operating Procedures

[0246] Add 3.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and 15 mL of water to a 50 mL three-necked flask. Stir and cool to 0-5 °C. Add 10% NaOH solution dropwise until the solid is completely dissolved, controlling the pH to 8. Slowly add 3.13 g of 3-(2-chlorophenyl)-5-methylisoxazole-4-carboxyl chloride, controlling the pH to 8. After the addition is complete, react at 0-5 °C for 2 hours, maintaining the pH at 8, and monitor the reaction by TLC. After the reaction is complete, adjust the pH of the reaction solution to 2 with 1 M HCl solution. The solid precipitates out, is filtered, and the filter cake is washed twice with 5 mL of cold water at 2 °C. Dry to obtain 4.25 g of crude product.

[0247] 1.0 g of crude product was purified by reversed-phase rapid chromatography under the following conditions: C18 silica gel column; mobile phase was a mixture of acetonitrile and pure water, with a gradient change of 5% to 50% over 30 minutes; detection wavelength was 254 nm. The purified fraction was freeze-dried to obtain 100 mg of (6R,7R)-7-(3-(2-chlorophenyl)-5-methylisoxazol-4-carboxamido)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid, which was a white solid.

[0248] 1 H NMR (400 MHz, DMSO-d6) δ 9.17 – 9.09 (m, 1H), 7.62 – 7.39 (m, 4H), 5.71 (s, 1H), 5.08 (dd, J = 11.2, 4.8 Hz, 1H), 4.77 (s, 1H), 3.84 (dq, J =13.6, 7.2 Hz, 1H), 3.72 – 3.64 (m, 1H), 3.50 (d, J = 17.7 Hz, 1H), 3.41 (s,1H), 2.64 (d, J = 4.4 Hz, 3H), 2.11 (s, 1H), 1.97 – 1.78 (m, 2H), 1.70 – 1.56 (m, 1H).

[0249] LCMS (ESI(-)): 488.0, 489.9.

[0250] Example 20

[0251] F50-108 synthesis

[0252] 1. Chemical reaction formula

[0253]

[0254] 2. Operating Procedures

[0255] In a 50 mL three-necked flask, add 3.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and 9 mL of water. Stir and cool to 0-5 °C, then add ammonia dropwise to completely dissolve the solid, maintaining pH at 8. Weigh 3.13 g of 3-(2,6-dichlorophenyl)-5-methylisoxazole-4-carboxyl chloride, dilute with 15 mL of acetone, and add the resulting solution dropwise to the reaction system, maintaining pH at 8 with ammonia. After the addition is complete, react at 0-5 °C for 2 hours, maintaining pH at 8, and monitor the reaction by TLC. After the reaction is complete, adjust the pH of the reaction solution to 2 with 1 M HCl solution, causing the solid to precipitate. Filter the solution, wash the filter cake twice with 5 mL of cold water at 2 °C, and dry to obtain 4.11 g of crude product.

[0256] 1.0 g of crude product was purified by reversed-phase rapid chromatography under the following conditions: C18 silica gel column; mobile phase was a mixture of acetonitrile and pure water, with a gradient change of 5% to 50% over 30 minutes; detection wavelength was 254 nm. The purified fraction was freeze-dried to obtain 120 mg of (6R,7R)-7-(3-(2,6-dichlorophenyl)-5-methylisoxazol-4-carboxamido)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid, which was a white solid.

[0257] 1H NMR (400 MHz, DMSO-d6) δ 9.16 (t, J = 8.1 Hz, 1H), 7.68 – 7.49 (m,3H), 5.67 (ddd, J = 19.2, 8.2, 4.7 Hz, 1H), 5.08 (dd, J = 7.9, 4.7 Hz, 1H), 4.76 (dd, J = 8.9, 6.7 Hz, 1H), 3.87 (q, J = 7.3 Hz, 1H), 3.70 (td, J = 7.8,5.2 Hz, 1H), 3.50 (dd, J = 17.3, 14.8 Hz, 2H), 2.71 (d, J = 6.0 Hz, 3H), 2.11(ddd, J = 12.6, 9.9, 5.9 Hz, 1H), 2.00 – 1.78 (m, 2H), 1.65 (ddq, J = 26.5,12.1, 8.7 Hz, 1H).

[0258] LCMS(ESI(-)):522.0,524.0.

[0259] Example 21

[0260] F50-109 synthesis

[0261] 1. Chemical reaction formula

[0262]

[0263]

[0264] 2. Operating Procedures

[0265] first step:

[0266] Dissolve 3.0 g of (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 50 mL of DMF, and then dissolve completely after adding 4.79 g of DIEA. Add (R)-2-(4-ethyl-2,3-dioxomorpholine-1-carboxamide)-2-phenylacetic acid, and adjust the pH with DIEA to make the reaction alkaline. Add 3.38 g of HATU, and stir at room temperature for 1 hour. Monitor the reaction of the starting material by TLC until it is complete, and then stop the reaction. Add water and ethyl acetate, separate the layers, concentrate the organic layer under reduced pressure, and purify the residue by silica gel column chromatography to give 4.3 g of pale yellow solid.

[0267] Step Two:

[0268] Dissolve 1.0 g of (6R,7R)-7-((R)-2-(4-ethyl-2,3-diketopiramate-1-carboxamido)-2-phenylacetamyl)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thio-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid-4-nitrobenzyl ester in 6 mL of acetone. Stir until dissolved. Add 6.0 mL of water to the reaction solution, resulting in a pale yellow turbidity. Add 1.11 g of sodium dithionite in portions and adjust the pH to 7-8 with ammonia. Stir at room temperature for 1 hour. Monitor the reaction of the starting material by TLC until complete. Wash with dichloromethane, separate the aqueous phase, adjust the pH of the aqueous phase to approximately 2 with hydrochloric acid, and the solid precipitates. Filter, wash with water, and purify the wet product by reversed-phase silica gel column chromatography (pure water system). Freeze-dry to obtain 0.2 g of pale white solid.

[0269] 1 H NMR (400 MHz, DMSO-d6) δ 9.84 (dd, J = 7.3, 3.7 Hz, 1H), 9.38 (dd,J = 8.5, 4.1 Hz, 1H), 7.49 – 7.39 (m, 2H), 7.39 – 7.27 (m, 3H), 5.65 (dd, J =12.4, 7.3 Hz, 1H), 5.53 (ddd, J = 22.3, 8.6, 4.7 Hz, 1H), 4.97 – 4.84 (m,2H), 3.90 (td, J = 5.3, 2.7 Hz, 2H), 3.79 (m, J = 7.2 Hz, 1H), 3.68 – 3.59(m, 1H), 3.56 (m, J = 4.4 Hz, 2H), 3.41 (d, J = 7.0 Hz, 2H), 3.28 – 3.14 (m,2H), 2.09 (q, J = 6.5 Hz, 1H), 1.90 – 1.73 (m, 2H), 1.53 (dq, J = 12.1, 9.0Hz, 1H), 1.08 (t, J = 7.1 Hz, 3H).

[0270] LCMS (ESI(-)):570.0.

[0271] Example 22

[0272] Bioactivity evaluation

[0273] Cefvitine belongs to the third-generation cephalosporin class of antibiotics. Its antibacterial activity is comparable to other cephalosporins, and it is mainly characterized by its long-lasting effect. Previous studies have found cross-resistance between cefvitine and other third-generation cephalosporins, and it exhibits resistance to strains producing extended-spectrum β-lactamases. To screen for cefvitine derivatives with superior antibacterial activity, in vitro drug susceptibility testing was performed on 21 compounds. The results are reported below.

[0274] 1 strain tested

[0275] 1) Escherichia coli resistant to cefavirenz and producing extended-spectrum β-lactamase;

[0276] 2) Carbapenemase-producing Escherichia coli resistant to cefavirenz;

[0277] 3) Standard strain of Escherichia coli;

[0278] 4) Pseudomonas intermedius that are sensitive to and resistant to ceftriaxone;

[0279] 5) Enzyme-producing Staphylococcus aureus;

[0280] 6) Standard strain of Staphylococcus aureus;

[0281] 7) Cefavirenz-resistant Klebsiella pneumoniae and Pseudomonas aeruginosa.

[0282] 2 Experimental Methods

[0283] The minimum inhibitory concentrations (MICs) of 21 tested compounds, cefotaxime, cefotaxime, and ceftazidime against the tested bacterial strains were determined using the agar dilution method, with drug concentrations ranging from 0.0625 mg / L to 128 mg / L.

[0284] 3. Experimental Results

[0285] 3.1 Distribution of MIC values ​​of Escherichia coli

[0286] The statistical results of the distribution of MIC values ​​of cefotaxime, cefotaxime, and ceftazidime against Escherichia coli are as follows: Figure 1 As shown. By Figure 1 It can be seen that the MIC value of ceftazidime (CAZ) ranges from 0.125 to >128 μg / mL, and the number of strains with MIC values ​​in the range of 0.125 to 4 μg / mL accounts for 61.54% of the total number of strains; the MIC value of cefotaxime (CTX) ranges from 0.0625 to >128 μg / mL, and the number of strains with MIC values ​​in the range of 0.0625 to 4 μg / mL accounts for only 15.38% of the total number of strains; the MIC value of cefotaxime (INN) ranges from 0.5 to >128 μg / mL, and the number of strains with MIC values ​​in the range of 0.5 to 2 μg / mL accounts for only 7.69% of the total number of strains.

[0287] The statistical distribution of the MIC values ​​of 21 tested compounds against Escherichia coli is as follows: Figure 2 and Figure 3 As shown. By Figure 2 It can be seen that the six tested compounds have good antibacterial effects against Escherichia coli. The MIC values ​​are distributed as follows: F50-001, TBWX, and F50-004 all range from 0.5 to >128 μg / mL; F50-003 ranges from 16 to >128 μg / mL; F50-013 ranges from 0.0625 to >128 μg / mL; and F50-035 ranges from 4 to >128 μg / mL.

[0288] Among the tested compounds, F50-001 had the highest proportion of strains with a MIC value ≤ 2 μg / mL, with 6 strains accounting for 23.08% of the total. This was followed by TBWX, F50-004, and F50-013, accounting for 7.69% of the total. F50-003 and F50-035 had none. Of these six tested compounds, F50-001 showed the best antibacterial effect against cefotaxime-resistant Escherichia coli, even surpassing cefotaxime and cefotaxime.

[0289] Depend on Figure 3 It can be seen that the proportion of strains with MIC values ​​>128 μg / mL for the remaining 15 tested compounds is relatively high, all exceeding 76%, indicating that these 15 compounds have poor antibacterial effects against cefvitamin-resistant Escherichia coli.

[0290] 3.2 Distribution of MIC values ​​for Staphylococcus aureus

[0291] The statistical results of the distribution of MIC values ​​of cefotaxime, cefotaxime, and ceftazidime against Staphylococcus aureus (Pseudomonas intermedius and Staphylococcus aureus) are as follows: Figure 4 As shown. By Figure 4 It can be seen that the MIC value of cefotaxime (INN) ranges from 0.25 to 32 μg / mL, and the number of strains with MIC values ​​< 8 μg / mL accounts for 80.00% of the total number of strains, indicating good antibacterial effect; the MIC value of cefotaxime (CTX) ranges from 0.25 to 32 μg / mL, and the number of strains with MIC values ​​< 8 μg / mL accounts for 73.33% of the total number of strains, indicating good antibacterial effect; the MIC value of ceftazidime (CAZ) ranges from 4 to 128 μg / mL, and the number of strains with MIC values ​​< 8 μg / mL accounts for 26.67% of the total number of strains.

[0292] The statistical distribution of the MIC values ​​of 21 tested compounds against Staphylococcus aureus is as follows: Figure 5 and Figure 6 As shown. By Figure 5The MIC values ​​of the eight tested compounds against Staphylococcus aureus were distributed as follows: F50-93 had an MIC value range of 0.0625–2 μg / mL, showing better antibacterial effects than cefotaxime, cefotaxime, and ceftazidime; F50-101 had an MIC value range of 0.0625–8 μg / mL, with 86.67% of the strains having MIC values ​​< 8 μg / mL, indicating better antibacterial effects than cefotaxime; F50-095 and F50-096 both had MIC values ​​range of 0.0625–32 μg / mL, with 93.33% of the strains having MIC values ​​< 8 μg / mL, indicating even better antibacterial effects than cefotaxime; F50-109 had an MIC value range of 0.125–32 μg / mL, with MIC values ​​< 8 μg / mL. The number of strains with MIC values ​​of 0.0625–8 μg / mL accounted for 93.33% of the total number of strains; the MIC value distribution range of F50-101 was 0.0625–8 μg / mL, with strains having MIC values ​​<8 μg / mL accounting for 86.67% of the total number of strains, and its antibacterial effect was better than that of cefotaxime; the MIC value distribution range of F50-013 was 0.0625–128 μg / mL, with strains having MIC values ​​<8 μg / mL accounting for 86.67% of the total number of strains; the MIC value distribution range of F50-100 was 0.125–64 μg / mL, with strains having MIC values ​​<8 μg / mL accounting for 86.67% of the total number of strains; and the MIC value distribution range of F50-103 was 0.25–64 μg / mL, with strains having MIC values ​​<8 μg / mL accounting for 80.00% of the total number of strains.

[0293] Overall, all eight compounds showed antibacterial effects against Staphylococcus aureus, with F50-93 exhibiting the best antibacterial effect.

[0294] Depend on Figure 6 It can be seen that the MIC values ​​of Staphylococcus against the other 13 tested compounds ranged from 0.125 to >128 μg / mL. The compounds with the concentrated distribution range of 0.125 to 4 μg / mL were: F50-099, F50-107, F50-106, F50-003, TBWX, and F50-108. These 6 compounds had better antibacterial effects than ceftazidime.

[0295] 3.3 Distribution of MIC values ​​for Klebsiella pneumoniae and Pseudomonas aeruginosa

[0296] Almost all of the compounds had MICs >128 μg / mL against both bacteria; only F50-93 and F50-107 had MICs of 0.0625 μg / mL and 0.5 μg / mL against Pseudomonas aeruginosa, respectively.

[0297] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An antibacterial compound, characterized in that, The structural formula is: 。 2. A method for preparing an antibacterial compound, characterized in that, The preparation method of (6R,7R)-8-oxo-3-((S)-tetrahydrofuran-2-yl)-7-(2-(thiophen-2-yl)acetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid is as follows: In a reaction vessel, (6R,7R)-7-amino-8-oxo-3-((S)-tetrahydrofuran-2-yl)-5-thia-1-azabicyclo[4.2.0] is added. [0] Oct-2-en-2-carboxylic acid, dichloromethane, and water were stirred and cooled to 0℃~5℃. NaOH solution was added dropwise to completely dissolve the solid, and the pH was controlled at 8. 2-(thiophen-2-yl)acetyl chloride was added dropwise, and the pH was controlled at 8. After the addition was complete, the reaction was carried out at 0℃~5℃, and the pH was maintained at 8. After the reaction was complete, the mixture was allowed to stand and separated. The dichloromethane phase was concentrated under reduced pressure until dry. Water was then added, and the mixture was filtered. The filter cake was washed with water to purify the product.

3. The method for preparing the antibacterial compound according to claim 2, characterized in that: Purification was performed using reverse rapid chromatography.

4. The use of the antibacterial compound of claim 1 in the preparation of a medicament for treating diseases in humans and animals caused by bacteria.

5. The application according to claim 4, characterized in that: The bacteria are either Gram-negative or Gram-positive.

6. The application according to claim 5, characterized in that: The bacteria in question is Staphylococcus aureus.

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