New oral β-lactamase inhibitor, and preparation thereof and use thereof

Abstract

The present invention belongs to the field of medicinal chemistry. Disclosed are an oral β-lactamase inhibitor, and a preparation method therefor and the use thereof. The present invention specifically relates to a compound as represented by formula I or an optical isomer thereof, and the use thereof as an inhibitor for treating diseases associated with bacterial infections.

Description

A novel oral β-lactamase inhibitor, its preparation and application Technical Field

[0001] This invention relates to the pharmaceutical field, specifically to novel oral β-lactamase inhibitor compounds. This invention also provides the application of β-lactamase inhibitors and pharmaceutical compositions thereof in the treatment of bacterial infections, and further includes overcoming bacterial antibiotic resistance. Background Technology

[0002] For the past half-century, antibiotics have been an effective tool in treating infectious diseases. From the development of antibiotics until the late 1980s, developed countries had almost completely controlled bacterial infections. However, with the widespread use of antibiotics, various resistance mechanisms have gradually become prevalent, seriously threatening the clinical efficacy of antimicrobial therapy. The increase in antibiotic-resistant strains is particularly common in major hospitals and nursing homes, with consequences including higher morbidity and mortality, longer hospital stays, and increased treatment costs.

[0003] Many bacteria have evolved β-lactamases, which can inactivate a variety of β-lactam antibiotics. The most important mechanism of β-lactam antibiotic resistance is the production of β-lactamases by bacteria. These enzymes covalently bind to the carbonyl group on the β-lactam ring of β-lactam antibiotics, causing hydrolysis and inactivation. Currently, more than 300 types of β-lactamases are known. According to the Bush classification, β-lactamases are divided into four groups based on their preferred substrate and inhibitor profiles; while Ambler classifies them into four categories (A, B, C, and D) based on amino acid homology sequences. The active group in categories A, C, and D is serine, while the active group in category B is Zn. 2+ It belongs to the class of metalloenzymes. Currently used β-lactamase inhibitors (such as clavulanic acid, sulbactam, tazobactam, etc.) interact with class A and B β-lactamases, blocking their destruction of the β-lactam ring, thereby effectively combating bacterial resistance.

[0004] Oral therapy is a cost-effective means of treating bacterial infections, both in community settings and as a "de-escalation" treatment following intravenous administration. For decades, fluoroquinolone antibiotics (such as levofloxacin) have been the primary choice for this type of treatment. However, the increasing development of resistance to these drugs has limited their use. In recent years, oral β-lactams have filled this gap to some extent, but the emergence of extended-spectrum β-lactamases and carbapenemases has also limited their efficacy. In the past decade, we have made significant progress in identifying inhibitors that inhibit cephalosporin and carbapenem-hydrolyzing β-lactamases. For example, avibactam, rabrabactam, and wabobactam are currently approved for use in fixed combinations with β-lactams. However, these drugs are only available for intravenous administration and are typically only available in hospital settings. Therefore, treatment options are limited for patients with severe drug-resistant infections who are otherwise healthy and do not require hospitalization, or for patients who could be discharged but require antibiotic treatment from an outpatient setting (also known as "oral conversion therapy"). The demand for novel oral medications has spurred extensive research. Currently, while several broad-spectrum β-lactamase inhibitors are being developed as oral prodrugs, such as ETX0282, VNRX-7145, and ARX1796, which exhibit inhibitory activity against classes A, C, and D enzymes, their effectiveness against Enterobacterial infections, which currently cover class B metalloenzymes, is limited. To date, no oral β-lactamase inhibitors have been approved, and resistance rates to conventional antibiotics continue to rise.

[0005] In view of this, the present invention develops a novel oral β-lactamase inhibitor. This inhibitor is effective not only against four types of β-lactamases (A, B, C, and D), but also effectively inhibits the activity of carbapenem-resistant bacteria such as Acinetobacter baumannii, Enterobacteriaceae, and Pseudomonas aeruginosa. It exhibits significantly high oral bioavailability, meeting the clinical need for oral therapeutic drugs for diseases caused by bacterial infections. Summary of the Invention

[0006] This invention provides a β-lactamase inhibitor, which is a compound of formula (I) or its optical isomer:

[0007] in,

[0008] L is selected from -C(O)- and -C(O)NR. a -OC(=O)-, -(CR) a R b ) i -C(=O)O- or -OC(=O)O-;

[0009] X is selected from direct bond or -(CR) c R d )k -(CH2) n -;

[0010] R 1 Selected from H, halogens, -CN, -OH, -NH2, C 1-6 Alkyl, C 3-12 Cycloalkyl, 3-12 membered heterocyclic groups, C 6-12 Aryl, 5-12 heteroaryl, -C(O)R 2 -C(O)OR 2 -C(O)NR 2 R 3 -NR 2 C(O)R 3 -NR 2 R 3 -OR 2 -OC(O)R 2 -OC(O)NR 2 R 3 -NR 2 C(O)NR 3 R 4 -NR 2 C(O)OR 3 -SR 2 -S(O)R 2 -S(O)2R 2 -S(O)NR 2 R 3 -S(O)2NR 2 R 3 or -NR 2 S(O)2R 3 The C 3-12 Cycloalkyl, 3-12 membered heterocyclic groups, C 6-12 The aryl and 5-12 heteroaryl groups are each independently and selectively coupled with one or more R groups. 5 replace;

[0011] R a and R b Each is independently selected from H, halogen, or C. 1-6 Alkyl; or R a and R b The atoms connected to them combine to form C 3-6 cycloalkyl, the C 1-6 The alkyl group may optionally be substituted with one or more halogens;

[0012] R c and R d Each is independently selected from H, halogen, or C. 1-6 Alkyl; or R c and R dThe atoms connected to them combine to form C 3-6 cycloalkyl, the C 1-6 The alkyl group may optionally be substituted with one or more halogens;

[0013] R 2 R 3 and R 4 Each is independently selected from C 1-6 Alkyl, C 3-12 Cycloalkyl, 3-12 membered heterocyclic groups, C 6-12 Aryl or 5-12 heteroaryl groups;

[0014] R 5 Selected from halogens, -CN, -OH, -NH2, C 1-6 Alkyl, -C(O)R 2 -C(O)OR 2 -C(O)NR 2 R 3 -NR 2 C(O)R 3 NR 2 R 3 -OR 2 -OC(O)R 2 -OC(O)NR 2 R 3 -NR 2 C(O)NR 3 R 4 -NR 2 C(O)OR 3 -SR 2 -S(O)R 2 -S(O)2R 2 -S(O)NR 2 R 3 -S(O)2NR 2 R 3 or -NR 2 S(O)2R 3 ;

[0015] m can be 1, 2, 3, or 4;

[0016] n is 1, 2, 3, or 4;

[0017] i can be 0, 1, 2, 3 or 4;

[0018] k can be 0, 1, 2, 3 or 4.

[0019] In some implementations, L is selected from -OC(=O)-, -CH2C(=O)O-, -CF2C(=O)O-, -C(CH3)2C(=O)O-, -C(O)NCH3- or -OC(=O)O-; preferably, L is -OC(=O)-.

[0020] In some implementation schemes, R a Selected from H, F or -CH3.

[0021] In some implementation schemes, R b Selected from H, F or -CH3.

[0022] In some embodiments, X is selected from direct bond, -CH2-, -(CH2)3-, -C(CH3)2-CH2-, -CH(CH3)-, -CH(CH3)-(CH2)2-, -CH(CH3)-(CH2)3-, -CH(C2H5)-(CH2)-, or -CH(C2H5)-(CH2)3-; preferably, X is -CH(C2H5)-(CH2)-.

[0023] In some implementation schemes, R c Selected from H.

[0024] In some implementation schemes, R d Selected from H, -CH3, or -C2H5.

[0025] In some implementation schemes, R 1 Selected from -CH3, -OCH3, -OC(O)CH3, Preferably, R 1 It is -CH3.

[0026] In some implementation schemes, R 1 Selected from -C(O)N(CH3)2.

[0027] In some implementation schemes, R 2 Selected from H or -CH3.

[0028] In some implementations, L is -OC (=O)-, X is -CH(C2H5)-(CH2)-, and R is... 1 It is -CH3.

[0029] In some implementations, the Selected from

[0030] In some implementations, the Selected from

[0031] In some embodiments, the compound of formula (I) is any one of the following compounds:

[0032] In some embodiments, the compound or its optical isomer can be used in combination with one or more other antibiotics for the treatment of bacterial infections.

[0033] In some embodiments, the other antibiotic is selected from telbipenem, cefbufen, cefixime, ceftriaxone, cefdinir, cefpodoxime, pimecrolimus, cefaclor, cefuroxime, cefalexin, or a combination of two or more thereof; preferably, it is selected from telbipenem, cefbufen, cefixime, ceftriaxone, cefdinir, or cefpodoxime; more preferably, it is selected from telbipenem, cefbufen, or cefixime.

[0034] In some embodiments, the use of the aforementioned compounds, their optical isomers, or any of the aforementioned pharmaceutical compositions in the preparation of a medicament for treating bacterial infections is further included.

[0035] In some implementations, the bacterial infection type includes infections selected from Klebsiella pneumoniae, Escherichia coli, Escherichia coli, Enterobacter cloacae, Acinetobacter baumannii, or Pseudomonas aeruginosa.

[0036] Definitions and Explanations

[0037] Unless otherwise stated, the terms used in the specification and claims have the following meanings.

[0038] "alkyl" refers to a straight-chain or branched saturated aliphatic hydrocarbon group. In some embodiments, the alkyl group has 1 to 6 carbon atoms. For example, as used herein, the term "C 1-6 "Alkyl" refers to a linear or branched group having 1 to 6 carbon atoms (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl or n-hexyl).

[0039] "Cycloalkyl" refers to a monocyclic or polycyclic hydrocarbon system that is saturated or partially unsaturated. For example, as used herein, the term "C" refers to... 3-12 "Cycloalkyl" refers to a cycloalkyl group having 3 to 12 cyclic carbon atoms. It can be a monocycloalkyl group, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl, or it can be a bicycloalkyl group.

[0040] "Heterocyclic group" refers to a ring system having at least one cyclic alkyl or cyclic alkenyl group containing a heterocycle, wherein the heteroatom includes, but is not limited to, oxygen, nitrogen, phosphorus, and sulfur atoms. The heterocyclic group can include monocyclic or polycyclic groups (e.g., having 2, 3, or 4 fused rings, spirocyclic, bridged rings, etc.). The heterocyclic group can be connected to other parts of the compound via cyclic carbon atoms or cyclic heteroatoms.

[0041] "Aryl" refers to an all-carbon monocyclic or fused polycyclic aromatic group having a conjugated π-electron system. For example, as used herein, the term "C" refers to a carbon-based monocyclic or polycyclic aromatic group. 6-12 "Aryl" refers to an aryl group containing 6 to 12 carbon atoms, such as phenyl or naphthyl.

[0042] "Heteroaryl" refers to a monocyclic or polycyclic aromatic group containing one or more identical or different heteroatoms, including monocyclic heteroaryl groups and bicyclic or polycyclic ring systems containing at least one heteroaryl ring (an aromatic ring system containing at least one heteroatom). The heteroaryl group is preferably 5 to 12-membered, more preferably 5- or 6-membered, such as imidazolyl, furanyl, thiophene, thiazolyl, pyrazolyl, oxazolyl, pyrroleyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, thiadiazole, pyrazinyl, etc., preferably triazolyl, thiophene, imidazolyl, pyrazolyl, oxazolyl, pyrimidinyl, or thiazolyl; more preferably pyrazolyl, pyrroleyl, and oxazolyl. The heteroaryl ring can be fused to an aryl, heterocyclic, or cycloalkyl ring, wherein the ring connected to the parent structure is the heteroaryl ring.

[0043] "Halogen" refers to F, Cl, Br or I.

[0044] All hydrogen atoms described in this invention can be replaced by their isotope deuterium, and any hydrogen atom in the compounds of the embodiments of this invention can also be replaced by a deuterium atom.

[0045] The term "substitution" refers to the replacement of one or more hydrogen atoms on a particular atom by a substituent, provided that the valence state of the particular atom is normal and the substituted compound is stable.

[0046] The term “optional” means that the event or condition described below may occur but is not required to occur, and the description includes both the scenario in which the event or condition occurs and the scenario in which the event or condition does not occur.

[0047] The solvents used in this invention are commercially available. The following abbreviations are used in this invention: KMnO4 refers to potassium permanganate; H2SO4 refers to potassium sulfate; tBuOH refers to tert-butanol; DMAP refers to 4-dimethylaminopyridine; MeOH refers to methanol; Pd(OAc)2 refers to palladium acetate; CataCXium A refers to n-butylbis(1-adamantyl)phosphine; Cs2CO3 refers to cesium carbonate; HCl refers to hydrochloric acid; EtOAc refers to ethyl acetate; LiOH refers to lithium hydroxide; THF refers to tetrahydrofuran; Ag2SO4 refers to silver sulfate; Boc2O refers to ditert-butyl dicarbonate; Pd(tBu3P)2 refers to bis(tri-tert-butylphosphine)palladium; Tol refers to toluene; Pinanediol refers to pinacol; Pd / C palladium on carbon catalyst; MeB(OH)2 refers to methylboronic acid; Conc.HCl refers to concentrated hydrochloric acid. K2CO3 refers to potassium carbonate; KI refers to potassium iodide; DMF refers to N,N-dimethylformamide; NaI refers to sodium iodide; Acetone refers to acetone; DIEA refers to N,N-diisopropylethylamine; NMP refers to N-methylpyrrolidone; NaHCO3 refers to sodium bicarbonate; TBAHSO4 refers to tetrabutylammonium bisulfate; DCM refers to dichloromethane; TBAF refers to tetrabutylammonium fluoride; TEA refers to triethylamine; DMPA refers to 4-dimethylaminopyridine; H2O refers to water; Saline refers to physiological saline. Detailed Implementation

[0048] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0049] Example 1

[0050] Step 1: At room temperature, potassium permanganate (440.82 g, 2.789 mol) was added dropwise to a mixed solution of 1-bromo-4-methoxy-2,3-dimethylbenzene (compound 1, 100 g, 0.465 mol) in tert-butanol (150 mL) and water (1200 mL). The reaction solution was stirred at 100 °C for 16 hours. After the reaction was completed, the solution was filtered through diatomaceous earth, the pH of the filtrate was adjusted to 1-2, and the solution was concentrated to obtain crude compound 1-2 (150 g). The product was directly used in the next step.

[0051] LCMS(ESI)calcd for C9H7BrO5[MH] + m / z 273,275,found 272.95,274.95.

[0052] Step 2: Add concentrated sulfuric acid (50 mL) to a methanol (500 mL) solution of 3-bromo-6-methoxybenzene-1,2-dicarboxylic acid (75 g of crude compounds 1-2 from the previous step, 0.273 mol). Stir the reaction mixture at 65 °C for 16 hours. After the reaction is complete, concentrate the methanol. Dilute the remaining solution with water, adjust the pH to 7-8, extract with ethyl acetate, wash, dry, and concentrate. The crude product is pulped (petroleum ether / ethyl acetate = 10 / 1) to give a yellow solid product (compounds 1-3, 16.7 g, 20.21% yield).

[0053] 1 H NMR (400MHz, DMSO-d6) δ7.81(d,J=9.2Hz,1H),7.26(d,J=9.2Hz,1H),3.84(s,3H),3.82(s,3H),3.77(s,3H).

[0054] Step 3: To a solution of dimethyl 3-bromo-6-methoxyphthalate (compounds 1-3, 19.9 g, 0.066 mol), potassium N-aminomethyltrifluoroborate (23.36 g, 0.99 mol), cesium carbonate (64.22 g, 0.197 mol), n-butyldi(1-adamantyl)phosphine (4.71 g, 0.013 mol) in 1,4-dioxane (250 mL) and water (50 mL), palladium acetate (1.48 g, 0.007 mol) was added. The reaction mixture was stirred at 100 °C under nitrogen protection for 16 hours. The reaction mixture was filtered through diatomaceous earth, extracted with ethyl acetate, washed, dried, filtered, and concentrated. The residue was pulped (petroleum ether / ethyl acetate = 10 / 1) to give a yellow solid product (compounds 1-4, 17.2 g, 53.16% yield).

[0055] 1 H NMR (400MHz, DMSO-d6)7.68(d,J=8.8Hz,1H),7.49(d,J=8.8Hz,1H),4.72(s,2H),3.85(s,3H),3.83(s,3H),1.51(s,9H).

[0056] Step 4: Add hydrochloric acid / ethyl acetate solution (4M, 100mL) to 2-tert-butyl-4-methyl-5-methoxy-3-oxoisoindoline-2,4-dicarboxylic acid ester (compounds 1-4, 17.2 g, 0.053 mol), and stir at room temperature for 2 hours. After the reaction is complete, filter to give a yellow solid product (compounds 1-5, 11.7 g, 99.06% yield).

[0057] 1H NMR (400MHz, DMSO-d6) δ8.63(s,1H),7.60(d,J=8.8Hz,1H),7.34(d,J=8.8Hz,1H),4.31(s,2H),3.83(s,3H),3.79(s,3H).

[0058] Step 5: Lithium hydroxide hydrate (6.64 g, 0.162 mol) was added to a mixture of methyl 5-methoxy-3-oxoisoindoline-4-carboxylic acid (compounds 1-5, 11.7 g, 0.053 mol) in tetrahydrofuran (100 mL) / methanol (100 mL) / water (100 mL). The mixture was stirred at 65 °C for 16 hours. After the reaction was completed, the mixture was concentrated, the pH was adjusted to 2-3, and the mixture was filtered to give a yellow solid product (compounds 1-6, 9.50 g, 86.77% yield).

[0059] 1 H NMR (400MHz, DMSO-d6) δ12.97(s,1H),8.58(s,1H),7.54(d,J=8.4Hz,1H),7.31(d,J=8.4Hz,1H),4.30(s,2H),3.83(s,3H).

[0060] Step 6: Liquid bromine (22.01 g, 137.70 mmol) was added dropwise to a concentrated sulfuric acid solution (100 mL) of 5-methoxy-3-oxoisoindoline-4-carboxylic acid (compounds 1-6, 9.5 g, 24.10 mmol) and silver sulfate (17.17 g, 55.01 mmol). The reaction mixture was stirred at 80 °C for 16 hours. After the reaction was completed, the mixture was cooled to room temperature, and then added to ice water. The solid precipitated and was filtered to obtain the crude product (compounds 1-7, 36.0 g), which was used directly in the next step.

[0061] Step 7: Add 4-dimethylaminopyridine (5.84 g, 0.048 mol) to a solution of crude 6-bromo-5-hydroxy-3-oxoisoindole-4-carboxylic acid (compounds 1-7, 36.0 g, 0.048 mol, 30% purity) and di-tert-butyl dicarbonate (93.89 g, 0.430 mol) in tert-butanol (150 mL) and tetrahydrofuran (150 mL). Stir the reaction mixture at 60 °C for 3 hours. Concentrate the reaction mixture under vacuum, and purify the residue by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 6 / 1) to give a white solid product (compounds 1-8, 8.60 g, 33.89% yield).

[0062] 1H NMR (400MHz, DMSO-d6) δ8.14(s,1H),4.79(s,2H),1.53(s,9H),1.52(s,9H),1.49(s,9H).

[0063] Steps 8-9: Under nitrogen atmosphere, add 0.83 g (0.002 mol) of di(tri-tert-butylphosphine)palladium to a toluene (130 mL) solution of compounds 1-8 (8.60 g, 0.016 mol), vinylboronic acid pinacol ester (2.99 g, 0.019 mol), and triethylamine (3.28 g, 0.032 mol). Stir the reaction mixture at 80 °C for 3 hours. Filter the reaction mixture, concentrate the filtrate to obtain the crude product (compounds 1-9, 9.5 g). Add (1R,2R,3S,5R)-(-)-2,3-pinenediol (13.45 g, 0.079 mol) to a tetrahydrofuran (100 mL) solution of the above crude product (compounds 1-9, 9.5 g, 0.016 mol). Stir the mixture at room temperature for 16 hours. After the reaction is complete, concentrate the reaction mixture. The residue was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 4 / 1) to give a yellow solid product (compounds 1-10, 4.20 g, 40.51% yield).

[0064] 1 H NMR (400MHz, DMSO-d6) δ8.11(s,1H),7.24(d,J=18.4Hz,1H),6.40(d,J=18.4Hz,1 H),4.81(s,2H),4.44(dd,J=8.4,1.2Hz,1H),2.30-2.40(m,1H),2.15-2.25(m,1H) ,2.02(t,J=5.2Hz,1H),1.85-1.92(m,1H),1.71-1.80(m,1H),1.53(s,9H),1.52(s ,9H),1.46(s,9H),1.38(s,3H),1.27(s,3H),1.00(d,J=10.8Hz,1H),0.84(s,3H).

[0065] Step 10: To a methanol (10 mL) solution of compound 1-10 (400 mg, 0.611 mmol), 10% palladium / carbon (65 mg) was added. The mixture was stirred for 2 hours under a hydrogen atmosphere, filtered, and the filtrate was concentrated. The residue was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 4 / 1) to give a yellow solid product (compound 1-11, 350 mg, 87.26% yield).

[0066] 1H NMR (400MHz, DMSO-d6) δ7.65 (s, 1H), 4.75 (s, 2H), 4.31 (dd, J = 8.4Hz, 1.2Hz, 2H), 2. 58-2.68(m,2H),2.25-2.34(m,1H),2.11-2.20(m,1H),1.92-2.00(t,J=5.6Hz,1H),1 .82-1.89(d,J=2.6Hz,1H),1.65-1.72(m,1H),1.52(s,9H),1.51(s,9H),1.47(s,9H ),1.31(s,3H),1.24(s,3H),1.03-1.10(m,2H),0.93(d,J=10.4Hz,1H),0.81(s,3H).

[0067] Step 11: Concentrated hydrochloric acid (1.5 mL) was added to a THF (1.5 mL) solution of compound 1-11 (150 mg, 0.229 mmol) and MeB(OH)2 (27.44 mg, 0.457 mmol), and the reaction mixture was stirred at room temperature for 5 h. The reaction solution was filtered and passed through a C100000-meter filter. 18 Column purification (eluting with 5%–95% MeCN / H2O in water containing 0.1% TFA) yielded a yellow solid compound Int 1 (10 mg, 17.37% yield).

[0068] LCMS(ESI)calcd for C 11 H 10 BNO5[M+H] + m / z 248.07, found 248.00

[0069] 1 H NMR(400MHz,MeOD)δ7.66(s,1H),4.50(s,2H),2.74(s,2H),0.95(s,2H).

[0070] Step 12: 2-Chloro-N,N-dimethylacetamide (236 mg, 1.94 mmol) was added to a DMF (5 mL) solution of compound Int 1 (200 mg, 0.65 mmol), K₂CO₃ (268 mg, 1.94 mmol), and KI (322 mg, 1.94 mmol), and the mixture was stirred at 50 °C under nitrogen protection for 12 hours. After the reaction was complete, the reaction mixture was filtered and purified by a C₁₈ column (eluting with 5% to 95% MeCN / H₂O, water containing 0.1% TFA) to give a white solid product 1 (50 mg, 23%).

[0071] LCMS(ESI)calcd for C15 H 18 BN2O6 + [M+H] + m / z 333.13, found 333.0.

[0072] 1H NMR (400MHz, Methanol-d4) δ7.41 (s, 1H), 5.09 (s, 2H), 4.36 (s, 2H), 3.10 (s, 3H), 2.99 (s, 3H), 2.87 (s, 2H), 1.11 (t, J = 7.8Hz, 2H).

[0073] Example 2

[0074] Step 1: Add NaI (16.5 g, 109.8 mmol) to an acetone (80 mL) solution of methyl 2-methylpropionate (5.0 g, 36.6 mmol), and stir the reaction mixture at 60 °C for 2 hours. Concentrate the reaction mixture, dilute with water, and extract with ethyl acetate. Dry the organic layer with anhydrous sodium sulfate and concentrate under vacuum to give a yellow oily product A-1 (6.0 g, 71.9%).

[0075] 1 H NMR(400MHz,Chloroform-d)δ5.91(s,2H),2.58-2.53(m,1H),1.17(s,3H),1.15(s,3H).

[0076] Step 2: Add methyl iodide 2-methylpropionate (compound A-1, 277 mg, 1.21 mmol) to a 2 mL NMP solution of compound Int 1 (100 mg, 0.40 mmol) and DIEA (157 mg, 1.21 mmol). Stir the reaction mixture at room temperature under nitrogen for 2 hours. Filter the reaction mixture and use C... 18 Column purification (eluting with 5% to 95% MeCN / H2O in water containing 0.1% TFA) yielded a white solid product 2 (23 mg, 16%).

[0077] LCMS(ESI)calcd for C 16 H 19 BNO7 + [M+H] + m / z 348.12, found 348.00.

[0078] 1H NMR (400MHz, Methanol-d4) δ7.41(s,1H),5.98(s,2H),4.37(s,2H),2.91(t,J=7. 8Hz, 2H), 2.64 (p, J = 7.0Hz, 1H), 1.20 (s, 3H), 1.18 (s, 3H), 1.12 (t, J = 7.8Hz, 2H).

[0079] Example 3

[0080] Step 1: Sodium iodide (819.43 mg, 5.467 mmol) was added to acetone (5 mL) containing methyl 2-ethylbutyrate (300 mg, 1.822 mmol). The mixture was stirred at 70 °C for 3 hours, cooled to room temperature and filtered. The filtrate was washed with sodium thiosulfate solution and sodium chloride aqueous solution, concentrated and dried to give crude brown oily product B-1 (320 mg, 68.57% yield).

[0081] Step 2: Add methyl 2-ethylbutyrate (compound B-1, 310.99 mg, 1.214 mmol) to a solution of compound Int 1 (100 mg, 0.405 mmol) and N,N-diisopropylethylamine (156.95 mg, 1.214 mmol) in N-methylpyrrolidone (3 mL), and stir the reaction mixture at room temperature for 1 h. Pass the reaction mixture through a C100000 ppm filter. 18 Column purification (eluting with 5%–30% MeCN / H2O in water containing 0.1% TFA) yielded off-white solid product 3 (22.95 mg, 13.91% yield).

[0082] LCMS(ESI)calcd for C 18 H 22 BNO7[M+H] + m / z 376.15, found 376.10

[0083] 1 H NMR (400MHz, Methanol-d4) δ7.41(s,1H),6.01(s,2H),4.37(s,2H),2.91(t,J=7.6Hz,2 H),2.24-2.34(m,1H),1.52-1.69(m,4H),1.11(t,J=7.6Hz,2H),0.90(t,J=7.6Hz,6H).

[0084] Example 4

[0085] Step 1: Sodium iodide (3.28 g, 21.90 mmol) was added to acetone (10 mL) containing methyl butyrate (1.0 g, 7.30 mmol). The mixture was stirred at 70 °C for 3 hours, cooled to room temperature and filtered. The filtrate was washed with sodium thiosulfate solution and sodium chloride aqueous solution, concentrated and dried to give crude brown oily product C-1 (1.0 g, 60.27% yield).

[0086] Step 2: Add methyl butyrate (267.92 mg, 1.21 mmol) to a solution of compound Int 1 (100 mg, 0.41 mmol) and N,N-diisopropylethylamine (156.95 mg, 1.214 mmol) in N-methylpyrrolidone (3 mL), and stir the reaction mixture at room temperature for 1 h. Pass the reaction solution through a C10 ... 18 Column purification (eluting with 5%–30% MeCN / H2O in water containing 0.1% TFA) yielded off-white solid product 4 (22.54 mg, 13.64% yield).

[0087] LCMS(ESI)calcd for C 16 H 18 BNO7[M+H] + m / z 348.12, found 348.05

[0088] 1 H NMR (400MHz, Methanol-d4) δ7.37-7.45(s,1H),5.98(s,2H),4.37(s,2H),2.90(t,J=8.0Hz, 2H), 2.40 (t, J = 7.2Hz, 2H), 1.62-1.70 (m, 1H), 1.11 (t, J = 8.0Hz, 2H), 0.96 (td, J = 7.6Hz, 3H).

[0089] Example 5

[0090] Step 1: Sodium iodide (1.02 g, 6.794 mmol) was added to acetone (5 mL) containing 400 mg (2.265 mmol) of chloromethyl cyclohexylcarboxylate. The mixture was stirred at 70 °C for 3 hours, cooled to room temperature and filtered. The filtrate was washed with sodium thiosulfate solution and sodium chloride aqueous solution, concentrated and dried to give crude brown oily product D-1 (500 mg, 82.36% yield).

[0091] Step 2: Add methyl cyclohexanecarboxylate (compound D-1, 325.57 mg, 1.214 mmol) to a solution of compound Int 1 (100 mg, 0.405 mmol) and N,N-diisopropylethylamine (156.95 mg, 1.214 mmol) in N-methylpyrrolidone (3 mL), and stir the reaction mixture at room temperature for 1 h. Pass the reaction mixture through a C100000 ppm filter. 18 Column purification (eluting with 5%–30% MeCN / H2O in water containing 0.1% TFA) yielded a white solid product 5 (7.5 mg, 4.59% yield).

[0092] LCMS(ESI)calcd for C 19 H 22 BNO7[M+H] + m / z 388.15, found 387.75

[0093] 1 H NMR (400MHz, Methanol-d4) δ7.42(s,1H),6.00(s,2H),4.38(s,1H),2.92(t,J=7.6Hz,1H),2.37-2.47(m,1H),1.93-2.00(m ,2H),1.74-1.82(m,2H),1.65-1.72(m,2H),1.42-1.53(m,2H),1.33-1.40(m,2H),1.28-1.32(m,1H),1.10(t,J=7.6Hz,1H).

[0094] Example 6

[0095] Step 1: Chloromethylsulfonyl chloride (compound E-1, 6.09 g, 0.037 mol) was added to a mixed solution of 2-cyclohexylacetic acid (5.0 g, 0.035 mol), sodium bicarbonate (11.76 g, 0.14 mol), and tetrabutylammonium bisulfate (1.19 g, 3.5 mmol) in water (45 mL) and dichloromethane (45 mL). The mixture was stirred at room temperature for 16 hours. The mixture was extracted twice with dichloromethane, the organic phases were combined, washed with water and brine, dried over sodium sulfate, and concentrated under vacuum to give the target product E-2 (5.30 g (approximately 90% purity), 71.08% yield), a colorless oil that could be used directly in the next reaction without further purification.

[0096] Step 2: 2-Cyclohexylacetic acid chloromethyl ester (E-2, 3.0 g, 15.7 mmol) and NaI (4.71 g, 31.4 mmol) were stirred at 70 °C for 3 h under nitrogen protection in acetone (45 mL). The mixture was filtered, and the filtrate was concentrated. The residue was diluted with EtOAc and washed with an aqueous solution of Na₂S₂O₃. The combined organic phases were dried over sodium sulfate. The mixture was concentrated under vacuum to give the target crude product E-3 (3.2 g, yield 61.15%), a yellow oil, which could be used in the next step without further purification.

[0097] 1 H NMR(400MHz,Chloroform-d)δ5.90(s,2H),2.21(d,J=7.1Hz,2H),1.72(ddd,J=15.4,11.0, 4.7Hz,5H),1.35-1.21(m,3H),1.16(tt,J=12.7,2.8Hz,1H),0.98(tt,J=12.0,6.1Hz,2H).

[0098] Step 3: A solution of compound Int 1 (120 mg, 0.4858 mmol), methyl 2-cyclohexylacetate (compound E-3, 411 mg, 1.457 mmol), and DIEA (188.35 mg, 1.457 mmol) in N-methylpyrrolidone (5 mL) was stirred at room temperature for 2 hours under a nitrogen atmosphere. The mixture was purified by reversed-phase column chromatography (eluting with 30%–45% MeCN / H2O, water containing 0.1% TFA) to give product 6 (20 mg, yield 9.24%) as a white solid.

[0099] LCMS(ESI)calcd for C 20 H 24 BNO7 + [M+H] + m / z 402.16, found 402.10.

[0100] 1 H NMR (400MHz, Methanol-d4) δ7.42 (d, J = 10.7Hz, 1H), 5.98 (d, J = 0.8Hz, 2H), 4.37 (s, 2H), 2.90 (t, J = 7.8Hz, 2H), 2.28(d,J=6.8Hz,2H),1.82-1.62(m,6H),1.34-1.15(m,3H),1.11(t,J=7.8Hz,1H),1.04-0.94(m,1H).

[0101] Example 7

[0102] Step 1: Cyclopentanecarboxylic acid (5.0 g, 43.80 mmol), NaHCO3 (11.0 g, 131.42 mmol), and TBAF (1 M in THF, 4.4 mL, 4.4 mmol) were dissolved in DCM / H2O (1 / 1, 200 mL). Chloromethylsulfonyl chloride (compound F-1, 6.5 g, 43.80 mmol) was added dropwise at 0 °C, and the reaction mixture was stirred at room temperature for 16 hours. The mixture was extracted with DCM, and the organic layer was concentrated under reduced pressure. The crude product was dissolved in EtOAc and washed with H2O (50 mL × 5). The organic layer was dried with Na2SO4 and concentrated under vacuum to give the colorless oily target product F-2 (5.6 g, 79%).

[0103] 1 H NMR (400MHz, Chloroform-d) δ5.70(s,2H),2.83-2.75(m,1H),1.94-1.86(m,2H),1.85-1.79(m,2H),1.73-1.67(m,2H),1.62-1.57(m,2H).

[0104] Step 2: Chloromethylcyclopentane carboxylate (F-2, 2.0 g, 12.30 mmol) was dissolved in acetone (30 mL), and NaI (5.5 g, 36.90 mmol) was added. The reaction mixture was stirred at 60 °C for 2 hours. After concentration, the reaction mixture was diluted with water and extracted with EtOAc. The organic layer was dried with Na2SO4 and concentrated under vacuum to give the target product F-3 (2.2 g, 70.4%) as a yellow oil.

[0105] 1 H NMR (400MHz, Chloroform-d) δ5.91(s,2H),2.76-2.71(m,1H),1.90-1.86(m,2H),1.83-1.79(m,2H),1.72-1.67(m,2H),1.60-1.56(m,2H).

[0106] Step 3: Compound Int 1 (200 mg, 0.81 mmol) and DIEA (314 mg, 2.43 mmol) were dissolved in NMP (5 mL), and iodomethylcyclopentane carboxylate (F-3, 617 mg, 2.43 mmol) was added. The reaction mixture was stirred at room temperature for 1 hour under a nitrogen atmosphere. After filtration, the reaction mixture was purified by C18 column chromatography (eluting with 5% to 95% MeCN / H2O containing 0.1% TFA) to give the target product 7 (78 mg, 25.8%) as a white solid.

[0107] LCMS(ESI)calcd for C 18 H 21 BNO7 + [M+H] + m / z 374.14, found 374.1.

[0108] 1 H NMR (400MHz, Methanol-d4) δ7.40 (s, 1H), 5.98 (d, J = 1.1Hz, 2H), 4.37 (d, J = 0.8Hz, 2H), 2.93-2.88 (m ,2H),2.84(td,J=8.6,7.9,6.5Hz,1H),1.95-1.81(m,4H),1.73-1.59(m,4H),1.12(t,J=7.8Hz,2H).

[0109] Example 8

[0110] Step 1: Cyclobutane carboxylic acid (5.0 g, 49.9 mmol), NaHCO3 (12.6 g, 149.8 mmol), and TBAF (1 M in THF, 5.0 mL, 5.0 mmol) were dissolved in DCM / H2O (1 / 1, 200 mL). Chloromethylsulfonyl chloride (compound G-1, 8.2 g, 49.9 mmol) was added dropwise at 0 °C, and the reaction mixture was stirred at room temperature for 16 hours. The reaction mixture was extracted with DCM, and the organic layer was concentrated under reduced pressure. The crude product was dissolved in ethyl acetate and washed with water (50 mL × 5). The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum to give a colorless oily product G-2 (5.5 g, 74.1% yield).

[0111] 1 H NMR (400MHz, Chloroform-d) δ5.71 (s, 2H), 3.20 (pd, J = 8.5, 1.1Hz, 1H), 2.37-2.28 (m, 2H), 2.27-2.19 (m, 2H), 2.04-1.90 (m, 2H).

[0112] Step 2: Chloromethylcyclobutane carboxylate (G-2, 3.5 g, 23.6 mmol) was dissolved in acetone (30 mL), and sodium iodide (10.6 g, 70.8 mmol) was added. The reaction mixture was stirred at 60 °C for 2 hours. After the reaction was complete, the mixture was concentrated, diluted with water, and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to give a yellow oily product G-3 (3.9 g, yield 68.6%).

[0113] 1 H NMR (400MHz, Chloroform-d) δ5.91 (s, 2H), 3.16 (dd, J = 8.2, 1.0Hz, 1H), 2.32-2.28 (m, 2H), 2.23-2.19 (m, 2H), 1.97-1.90 (m, 2H).

[0114] Step 3: Compound Int 1 (100 mg, 0.40 mmol) and DIEA (157 mg, 1.21 mmol) were dissolved in NMP (2 mL), and iodomethylcyclobutane carboxylate (486 mg, 2.02 mmol) was added. The reaction mixture was stirred at room temperature for 1 hour under a nitrogen atmosphere. After the reaction was complete, the mixture was filtered and passed through a C100000-2000 ppm filter. 18 Column purification (eluting with 5% to 95% acetonitrile / water solution containing 0.1% TFA) gave a white solid product 8 (21 mg, yield 14.5%).

[0115] LCMS(ESI)calcd for C 17 H 19 BNO7 + [M+H] + m / z 360.12, found 360.10.

[0116] 1 H NMR (400MHz, Methanol-d4) δ7.41-7.38(m,1H),5.98(s,2H),4.39-4.32(m,2H),3.30-3.20(m,1H),2.91-2.87(m,2H),2.36-2 .27(m,2H),2.23(dddd,J=11.6,6.1,3.9,1.8Hz,2H),2.02(dt,J=11.2,7.4Hz,1H),1.95-1.86(m,1H),1.11(t,J=7.8Hz,2H).

[0117] Example 9

[0118] Step 1: Dissolve chloromethylcyclopropane carboxylate (800 mg, 5.95 mmol) in acetone (10 mL), add sodium iodide (2675 mg, 17.84 mmol), and stir the reaction mixture at 60 °C for 2 hours. After the reaction is complete, concentrate the mixture, dilute with water, and extract with ethyl acetate. Dry the organic layer with anhydrous sodium sulfate, filter, and concentrate under reduced pressure to give a yellow oily product H-1 (900 mg, yield 67.0%).

[0119] 1H NMR (400MHz, Chloroform-d) δ5.91 (s, 2H), 1.63 (ddd, J = 8.0, 4.7, 3.4Hz, 1H), 1.11-1.06 (m, 2H), 0.94 (ddd, J = 7.9, 3.8, 3.0Hz, 2H).

[0120] Step 2: Compound Int 1 (100 mg, 0.40 mmol) and N,N-diisopropylethylamine (157 mg, 1.21 mmol) were dissolved in N-methylpyrrolidone (2 mL), and iodomethylcyclopropane carboxylate (compound H-1, 274 mg, 1.21 mmol) was added. The reaction mixture was stirred at room temperature for 1 hour under a nitrogen atmosphere. After the reaction was complete, the mixture was filtered and passed through a C100000-dimethylcyclopropane ether precipitate. 18 Column purification (eluting with 5% to 95% acetonitrile / water solution containing 0.1% TFA) gave a white solid product 9 (32 mg, yield 22.9%).

[0121] LCMS(ESI)calcd for C 16 H 17 BNO7 + [M+H] + m / z 346.11, found 346.0.

[0122] 1 H NMR (400MHz, Methanol-d4) δ7.40(s,1H),5.97(s,2H),4.37(s,2H),2.90(t,J=7.8Hz,2H),1.68(ddd,J =7.9,5.4,3.2Hz,1H),1.11(t,J=7.8Hz,2H),1.01(dt,J=4.7,3.0Hz,2H),0.96(dt,J=8.0,2.9Hz,2H).

[0123] Example 10

[0124] Step 1: Compound Int 1 (100 mg, 0.40 mmol), TEA (123 mg, 1.21 mmol), and DIEA (188.35 mg, 1.457 mmol) were dissolved in NMP (2 mL). Iodomethyl 2,2-dimethylpropionate (compound I, 392 mg, 1.62 mmol) was added. The reaction mixture was stirred at room temperature for 1 hour under a N2 atmosphere. After the reaction was complete, the mixture was filtered and passed through a C24 filter. 18 Column purification (eluting with 5% to 95% MeCN / H2O containing 0.1% TFA) yielded 10 (32 mg, 22.9%) of white solid product.

[0125] LCMS(ESI)calcd for C 17 H 21 BNO7 + [M+H] + m / z 362.14, found 362.10.

[0126] 1 H NMR (400MHz, Methanol-d4) δ7.41(d,J=1.0Hz,1H),5.98(s,2H),4.37(d,J=0.8Hz,2H),2.91(t,J=7.8Hz,2H),1.24(d,J=0.9Hz,9H),1.11(d,J=7.7Hz,2H).

[0127] Example 11

[0128] Step 1: Chloromethylsulfonyl chloride (compound J-1, 8.08 g, 0.049 mol) was added to a mixture of valeric acid (5.0 g, 0.049 mol), sodium bicarbonate (16.47 g, 0.196 mol), and tetrabutylammonium bisulfate (1.66 g, 4.9 mmol) in water (45 mL) and dichloromethane (45 mL). The mixture was stirred at room temperature for 16 h. The mixture was extracted twice with dichloromethane, the organic phases were combined, washed with water and brine, dried over sodium sulfate, and then concentrated under vacuum to give the target product J-2 (5.3 g (purity approximately 90%), yield 84.42%), a colorless oil that could be used in the next reaction without further purification.

[0129] 1 H NMR (400MHz, Chloroform-d) δ5.72-5.67(m,1H),2.38(td,J=7.7,2.2Hz,2H),1.64(dt,J=7.5,3.9Hz,2H),1.36(q,J=7.4Hz,2H),0.95-0.88(m,3H).

[0130] Step 2: A solution of tetrahydropyran-4-carboxylic acid chloromethyl ester (J-2, 2.5 g, 16.6 mmol) and sodium iodide (NaI, 4.98 g, 33.2 mmol) in acetone (40 mL) was stirred at 70 °C for 3 hours under a nitrogen atmosphere. The mixture was filtered, and the filtrate was concentrated. The residue was diluted with ethyl acetate (EtOAc) and washed with an aqueous solution of sodium thiosulfate (Na2S2O3). The organic phases were combined, dried over sodium sulfate, and then concentrated under vacuum to give the target product J-3 (2.3 g (purity approximately 85%), yield 48.80%) as a brown oil.

[0131] 1 H NMR (400MHz, Chloroform-d) δ5.91 (s, 2H), 2.34 (t, J = 7.8Hz, 2H), 1.63 (p, J = 7.5Hz, 2H), 1.41-1.32 (m, 2H), 0.92 (m, t, J = 7.6Hz, 3H).

[0132] Step 3: A solution of compound Int 1 (120 mg, 0.4858 mmol), methyl iodide valerate (compound J-3, 352.68 mg, 1.457 mmol), and DIEA (188.35 mg, 1.457 mmol) in N-methylpyrrolidone (5 mL) was stirred at room temperature for 2 hours under a nitrogen atmosphere. The mixture was purified by reversed-phase column chromatography (eluting with a 30%–45% acetonitrile (MeCN) / water system containing 0.1% trifluoroacetic acid (TFA)) to give final product 11 (23 mg, yield 13.1%) as a yellow solid.

[0133] LCMS(ESI)calcd for C 17 H 20 BNO7[M+H] + m / z 362.13, found 362.10.

[0134] 1 H NMR (400MHz, Methanol-d4) δ7.41(d,J=1.0Hz,1H),5.98(s,2H),4.37(d,J=0.8Hz,2H),2.90(t,J=7.8Hz,2H ),2.42(t,J=7.5Hz,2H),1.65-1.57(m,2H),1.41-1.34(m,2H),1.11(t,J=7.8Hz,2H),0.93(t,J=7.3Hz,3H).

[0135] Example 12

[0136] Steps 1-2: 2,2-Dimethylbutyric acid (5.0 g, 43.04 mmol), NaHCO3 (10.8 g, 129.13 mmol), and TBAF (1 M in THF, 4.3 mL, 4.3 mmol) were dissolved in DCM / H2O (1 / 1, 200 mL). Chloromethylsulfonyl chloride (compound K-1, 7.1 g, 43.04 mmol) was added at 0 °C, and the reaction mixture was stirred at room temperature for 16 hours. The mixture was extracted with DCM, and the organic layer was concentrated under reduced pressure. The crude product was dissolved in EtOAc and washed with H2O (50 mL × 5). The organic layer was dried with Na2SO4 and concentrated under vacuum to give a colorless oily intermediate. The intermediate was dissolved in acetone, and NaI (19.4 g, 129.13 mmol) was added. The reaction mixture was stirred at 60 °C for 2 hours. After the reaction was complete, the mixture was concentrated, diluted with water, and extracted with EtOAc. The organic layer was dried with Na2SO4 and concentrated under vacuum to give a yellow oily product K-3 (6.1 g, 55.3%).

[0137] 1 H NMR(400MHz,Chloroform-d)δ5.91(s,2H),1.59-1.56(m,2H),1.14(s,6H),0.87-0.83(m,3H).

[0138] Step 3: Dissolve compounds Int 1 (100 mg, 0.40 mmol), TEA (123 mg, 1.21 mmol), and DIEA (157 mg, 1.21 mmol) in NMP (2 mL), add iodomethyl 2,2-dimethylbutyrate (compound K-3, 311 mg, 1.21 mmol), and stir the reaction mixture at room temperature for 1 hour under a nitrogen atmosphere. After the reaction is complete, filter the mixture and pass it through a C100000-meter filter. 18 Column purification (eluting with 5% to 95% MeCN / H2O containing 0.1% TFA) yielded a white solid product 12 (10 mg, 5.3%).

[0139] LCMS(ESI)calcd for C 18 H 23 BNO7 + [M+H] + m / z 376.16, found 376.10.

[0140] 1H NMR (400MHz, Methanol-d4) δ7.41(s,1H),5.99(s,2H),4.37(s,2H),2.91(t,J=7.8Hz, 2H), 1.62 (q, J = 7.5Hz, 2H), 1.19 (s, 6H), 1.12 (t, J = 7.8Hz, 2H), 0.85 (t, J = 7.5Hz, 3H).

[0141] Example 13

[0142] Steps 1-2: 2-Methylpentanoic acid (compound L, 5.0 g, 43.04 mmol), NaHCO3 (10.8 g, 129.13 mmol), and TBAF (1 M in THF, 4.3 mL, 4.3 mmol) were dissolved in DCM / H2O (1 / 1, 200 mL). Chloromethylsulfonyl chloride (compound L-1, 7.1 g, 43.04 mmol) was added at 0 °C, and the reaction mixture was stirred at room temperature for 16 hours. The mixture was extracted with DCM, and the organic layer was concentrated under reduced pressure. The crude product was dissolved in EtOAc and washed with H2O (50 mL × 5). The organic layer was dried with Na2SO4 and concentrated under vacuum to give a colorless oily intermediate. The intermediate was dissolved in acetone, and NaI (19.4 g, 129.13 mmol) was added. The reaction mixture was stirred at 60 °C for 2 hours. After the reaction was complete, the mixture was concentrated, diluted with water, and extracted with EtOAc. The organic layer was dried with Na2SO4 and concentrated under vacuum to obtain the target product L-3 (5.7 g, 51.7%), which was yellow and oily.

[0143] 1 H NMR(400MHz,Chloroform-d)δ5.91-5.87(m,2H),2.46-2.41(m,1H),1.62(td,J=7.6,5.3 Hz,1H),1.43-1.37(m,1H),1.34-1.28(m,2H),1.11(d,J=7.1Hz,3H),0.89-0.85(m,3H).

[0144] Step 3: Compound Int 1 (120 mg, 0.49 mmol) and DIEA (188 mg, 1.46 mmol) were dissolved in NMP (3 mL), and iodomethyl 2-methylvalerate (compound L-3, 373 mg, 1.46 mmol) was added. The reaction mixture was stirred at room temperature for 1 hour under a nitrogen atmosphere. After the reaction was complete, the mixture was filtered and passed through a C10000-4000 ppm filter. 18Column purification (eluting with 5% to 95% MeCN / H2O containing 0.1% TFA) yielded a white solid product 13 (17 mg, 9.3%).

[0145] LCMS(ESI)calcd for C 18 H 23 BNO7 + [M+H] + m / z 376.16, found 376.10.

[0146] 1 H NMR (400MHz, Methanol-d4) δ7.40(s,1H),5.99(s,2H),4.37(s,2H),2.90(t,J=7.8Hz,2H),2.54(q,J=7.0Hz,1H),1.71-1.64(m, 1H), 1.43 (ddd, J=13.0, 6.4, 3.3Hz, 1H), 1.39-1.29 (m, 3H), 1.17 (d, J=7.1Hz, 3H), 1.10 (t, J=8.4Hz, 2H), 0.90 (t, J=7.3Hz, 3H).

[0147] Example 14

[0148] Step 1: Chloromethylsulfonyl chloride (6.65 g, 0.040 mol) was added dropwise to a mixture of 2-methylhexanoic acid (5.0 g, 0.038 mol), sodium bicarbonate (12.94 g, 0.154 mol), and tetrabutylammonium bisulfate (1.30 g, 3.84 mmol) dissolved in water (45 mL) and dichloromethane (45 mL). The mixture was stirred at room temperature for 16 hours. The mixture was extracted twice with dichloromethane, and the organic phases were combined, washed successively with water and brine, and then dried over sodium sulfate. The product was concentrated under vacuum to obtain the target product M-2 (5.60 g, purity approximately 90%, yield 73.47%), a colorless oil that could be used in the next reaction without further purification.

[0149] Step 2: A solution of methyl 2-methylhexanoate (M-2, 3.0 g, 15.1 mmol) and sodium iodide (NaI, 4.68 g, 31.2 mmol) in acetone (45 mL) was stirred at 70 °C for 3 hours under a nitrogen atmosphere. The mixture was filtered, and the filtrate was concentrated. The residue was diluted with ethyl acetate (EtOAc) and washed with an aqueous solution of sodium thiosulfate. The organic phases were combined, dried over sodium sulfate, and then concentrated under vacuum to give the target crude product M-3 (3.1 g, purity approximately 85%, yield 71.03%), a brown oily substance, which could be used for the next reaction without further purification.

[0150] 1 H NMR(400MHz,Chloroform-d)δ5.94-5.88(m,2H),2.47-2.40(m,1H),1.68-1.60(m,1H ),1.49-1.41(m,1H),1.34-1.25(m,4H),1.14(d,J=7.0Hz,2H),0.88(d,J=7.2Hz,3H).

[0151] Step 3: A solution of compound Int 1 (120 mg, 0.4858 mmol), methyl iodide 2-methylhexanoate (compound M-3, 393.66 mg, 1.457 mmol), and DIEA (188.35 mg, 1.457 mmol) in N-methylpyrrolidone (5 mL) was stirred at room temperature for 1.5 hours under a nitrogen atmosphere. The mixture was purified by reversed-phase column chromatography (eluting with 30%–50% MeCN / H2O, water containing 0.1% TFA) to give product 14 (26 mg, yield 12.37%) as a white solid.

[0152] 1 H NMR (400MHz, Methanol-d4) δ7.42(d,J=1.1Hz,1H),6.00(d,J=0.9Hz,2H),4.37(s,2H),2.91(t,J=7.8Hz,1H),2.51(p,J=7.0Hz,1H) ,1.71-1.63(m,1H),1.50-1.42(m,1H),1.36-1.26(m,4H),1.17(dd,J=6.9,0.9Hz,3H),1.12(t,J=7.9Hz,1H),0.88(t,J=6.8Hz,2H).

[0153] Example 15

[0154] Steps 1-2: Cyclopropylacetic acid (5.0 g, 49.94 mmol), NaHCO3 (12.6 g, 149.83 mmol), and TBAF (1 M in THF, 5.0 mL, 5.0 mmol) were dissolved in DCM / H2O (1 / 1, 200 mL). Chloromethylsulfonyl chloride (compound N-1, 8.2 g, 49.94 mmol) was added at 0 °C, and the reaction mixture was stirred at room temperature for 16 hours. The mixture was extracted with DCM, and the organic layer was concentrated under reduced pressure. The crude product was dissolved in EtOAc and washed with H2O (50 mL × 5). The organic layer was dried with Na2SO4 and concentrated under vacuum to give a colorless oily intermediate. The intermediate was dissolved in acetone, and NaI (22.5 g, 149.83 mmol) was added. The reaction mixture was stirred at 45 °C for 16 hours. After the reaction was complete, the mixture was concentrated, diluted with water, and extracted with EtOAc. The organic layer was dried with Na2SO4 and concentrated under vacuum to give a yellow oily product N-3 (4.8 g, 40.0%).

[0155] 1 H NMR (400MHz, Chloroform-d) δ5.92 (s, 2H), 2.24 (d, J = 7.2Hz, 2H), 1.07-1.01 (m, 1H), 0.58-0.55 (m, 2H), 0.18 (dd, J = 4.8, 1.3Hz, 2H).

[0156] Step 3: Iodomethyl-2-cyclopropylacetate (compound N-3, 350 mg, 1.46 mmol) was added to a solution of compound Int 1 (120 mg, 0.49 mmol) and DIEA (188 mg, 1.46 mmol) in NMP (3 mL). The reaction mixture was stirred at room temperature under nitrogen for 1 hour. The reaction mixture was filtered and treated with C... 18 Column purification (eluting with 5% to 95% MeCN / H2O containing 0.1% TFA) yielded a white solid product 15 (10 mg, 5.7%).

[0157] LCMS(ESI)calcd for C 17 H 19 BNO7 + [M+H] + m / z 360.12, found 360.05.

[0158] 1H NMR (400MHz, Methanol-d4) δ7.41(s,1H),5.99(s,2H),4.37(s,2H),2.91(t,J=7.8Hz,2H),2.33(d,J= 7.1Hz,2H),1.12(t,J=7.8Hz,2H),1.07-1.00(m,1H),0.57-0.52(m,2H),0.19(dt,J=6.0,4.6Hz,2H).

[0159] Example 16

[0160] Step 1: Chloromethylsulfonyl chloride (compound O-1, 7.21 g, 0.0437 mol) was added to a mixture of 2-ethylhexanoic acid (6.0 g, 0.0416 mol), sodium bicarbonate (13.98 g, 0.166 mol), and tetrabutylammonium bisulfate (1.61 g, 4.16 mmol) in water (60 mL) and dichloromethane (60 mL). The mixture was stirred at room temperature for 16 hours. The mixture was extracted twice with dichloromethane, the organic phases were combined, washed with water and brine, dried over sodium sulfate, and concentrated under vacuum to give product O-2 (5.60 g, yield 63.0%) as a colorless oil.

[0161] 1 H NMR (400MHz, Chloroform-d) δ5.73 (s, 1H), 2.38-2.29 (m, 1H), 1.75-1.40 (m, 4H), 1.35-1.21 (m, 4H), 0.91 (t, J = 7.2Hz, 3H), 0.88 (t, J = 7.2Hz, 3H).

[0162] Step 2: A solution of methyl 2-ethylhexanoate (O-2, 2.5 g, 13.0 mmol) and sodium iodide (3.90 g, 26.0 mmol) in acetone (45 mL) was stirred at 65 °C for 3 hours under nitrogen protection. The mixture was filtered, and the filtrate was concentrated. The residue was diluted with ethyl acetate and washed with an aqueous solution of sodium thiosulfate. The combined organic phases were dried over sodium sulfate and concentrated under vacuum to give crude product O-3 (2.5 g (purity approximately 85%), yield 57.69%), a yellow oil that could be used directly in the next reaction without further purification.

[0163] 1H NMR (400MHz, Chloroform-d) δ5.92(s,2H),2.31-2.25(m,1H),1.66-1.57(m,2H),1.57-1.41(m,2H),1.35-1.19(m,4H),0.89(dt,J=8.7,7.2Hz,6H).

[0164] Step 3: A solution of compound Int 1 (120 mg, 0.486 mmol), methyl iodide 2-ethylhexanoate (compound O-3, 393.66 mg, 1.46 mmol), and DIEA (188.35 mg, 1.46 mmol) in N-methylpyrrolidone (5 mL) was stirred at room temperature for 1 hour under nitrogen protection. The mixture was purified by reverse-phase column chromatography (eluting with a 40% to 50% acetonitrile / water solution containing 0.1% trifluoroacetic acid) to give product 16 (25 mg, yield 12.12%) as a white solid.

[0165] LCMS(ESI)calcd for C 20 H 26 BNO7[M+H] + m / z 404.18, found 403.75.

[0166] 1 H NMR (400MHz, Methanol-d4) δ7.41(s,1H),6.01(d,J=0.6Hz,1H),4.37(d,J=0.8Hz,1H),2.90(t,J=7.6Hz,2H),2.38-2.31(m,1H ),1.69-1.59(m,2H),1.58-1.47(m,1H),1.33-1.24(m,4H),1.11(t,J=7.8Hz,2H),0.89(t,J=7.2Hz,3H).0.85(t,J=7.2Hz,3H).

[0167] Example 17

[0168] Step 1: Dissolve Int1 (40 mg, 0.162 mmol) in 1 M NaOH (0.33 mL) and ACN (1 mL), and stir at room temperature for 5 min. Add a small amount of water and freeze dry to obtain yellow solid product 17 (35 mg, yield 70.00%).

[0169] LCMS(ESI)calcd for C 12 H 10 BNNa2O6[M+H]m / z 308.99, found 2247.55

[0170] 1 H NMR (400MHz, D2O) δ7.07 (s, 1H), 4.24 (s, 2H), 2.66 (t, J = 6.8Hz, 2H), 0.36 (t, J = 6.8Hz, 2H).

[0171] Bioactivity test

[0172] Experimental Example 1: Evaluation of the antibacterial effect of compound combined with antibiotic in a mouse thigh infection model.

[0173] 1. Experimental Objective

[0174] This study established a thigh infection model by inoculating CD-1 mice with Klebsiella pneumoniae and evaluated the antibacterial effects of cefixime and compound 3 in combination in the mouse thigh infection model.

[0175] 2. Experimental Procedure

[0176] 2.1 Laboratory Animals

[0177] CD-1 mice (6-8 weeks old), SPF grade, female.

[0178] 2.2 Strain Cultivation and Preparation

[0179] Using a sterile inoculation loop, pick up bacterial culture from a Klebsiella pneumoniae ATCC BAA-1705 glycerol cryopreservation tube and streak it onto a BHI plate. Incubate at 35±2℃ for approximately 17 hours. Pick a single colony from the overnight culture, suspend it in sterile physiological saline, vortex until homogeneous, and measure the OD value. 600 The value is used as the inoculation solution.

[0180] 2.3 Drug Preparation

[0181] Table 1. Preparation concentration and solvent of the test compound

[0182] 2.4 Animal Experiment Procedures

[0183] 2.4.1 Preprocessing

[0184] Day 0 is defined as the day of bacterial inoculation. Day 4: Cyclophosphamide is administered intraperitoneally at a dose of 150 mpk, once daily. Day 1: Cyclophosphamide is administered intraperitoneally at a dose of 100 mpk, once daily.

[0185] 2.4.2 Vaccination

[0186] On Day 0, an infectious dose of ~5.0E+06 CFU / mouse of bacterial suspension was injected intramuscularly into the right thigh at an inoculation volume of 100 μL / mouse.

[0187] 2.4.3 Administration

[0188] Administration began 2 hours after infection, via oral gavage (PO), at a frequency of BID. Specific dosages are shown in Table 2.

[0189] Table 2. Dosing Regimen

[0190] Note: 1. Day-4: The day of bacterial infection is Day 0, the four days before infection are Day-4, and so on;

[0191] 2.Vehicle: 10% DMSO+40% PEG300+5% Tween-80+45% Saline;

[0192] 3. BID: Interval 5 hours.

[0193] 2.4.4 Endpoint Operation

[0194] Animals in group G1 (Day 0): Mice were euthanized with CO2 2 hours after infection, and right thigh muscle was collected. Animals in groups G2-G5 (Day 0): Mice were euthanized with CO2 12 hours after infection, and right thigh muscle was collected. All tissues were weighed and placed in 50 mL centrifuge tubes containing 10 mL of sterile physiological saline. The tissues were homogenized using a homogenizer, and the bacterial load was determined.

[0195] 2.4.5 Detection Indicators

[0196] Animal weight; bacterial load in the right thigh muscle.

[0197] 3. Experimental Results

[0198] The experimental results showed that, compared with the 2h infection group (G1), the bacterial load in the 12h infection group steadily increased, indicating that the bacteria could be stably colonized in the tissue. Compared with the 12h infection group (G2), the use of 100mpk cefixime alone (G3) could not effectively reduce the bacterial load in the tissue; compared with the cefixime monotherapy group (G3), cefixime combined with different doses of compound 3 (G4 and G5) significantly reduced the tissue CFU by more than 2log (p < 0.001, Table 3).

[0199] Table 3. Bacterial load in mouse thigh tissue 12 h after drug administration

[0200] 4. Experimental Conclusions

[0201] In this experiment, a local infection model was established by inoculating Klebsiella pneumoniae into the thigh tissue of CD-1 mice, to evaluate the antibacterial effects of G1, G2, G3, G4 and G5 in the mouse local infection model. The experimental results show that 12 hours after administration, the bacterial load in the thigh tissue of animals in the two test article groups (G4 and G5) was significantly reduced compared with the group administered with cefixime alone. The above results suggest that Compound 3 can significantly restore the sensitivity to cefixime, and the oral administration of the two in combination has good in vivo antibacterial effect.

[0202] Experimental Example 2 Determination of Pharmacokinetics in Rats

[0203] 1. Experimental purpose:

[0204] SD rats were administered with the example compounds via single intravenous injection and gavage respectively, plasma samples at different time points were collected, and the bioavailability of Compound 3, Compound 8 and Compound 17 was calculated.

[0205] 2. Experimental protocol

[0206] 2.1 Test drugs

[0207] The example compounds 3, 8 and 17 of the present invention.

[0208] 2.2 Laboratory animals

[0209] ICR mice, SPF grade, male, purchased from Hunan SJA Laboratory Animal Co., Ltd., with the animal production license number (SCXK(Xiang)2021-0002).

[0210] 2.3 Drug preparation:

[0211] Preparation of test solution for intravenous administration of Example Compound 17: Weigh 1.59 mg of Compound 17 test sample into a glass vial; add 0.338 mL of DMSO, mix well, then add 0.677 mL of Solutol HS-15 (polyethylene glycol (15)-hydroxystearate), mix well, then add 5.751 mL of normal saline, vortex to mix, and perform ultrasonication to obtain a clear and transparent solution with a concentration of 0.2 mg / mL.

[0212] Preparation of test solution for gavage administration of Example Compound 17: Weigh 14.33 mg of Compound 17 test sample into a glass vial; add 0.610 mL of DMSO, mix well, then add 1.220 mL of Solutol HS-15, mix well, then add 10.367 mL of normal saline, vortex to mix, and perform ultrasonication to obtain a clear and transparent solution with a concentration of 1.0 mg / mL.

[0213] Example: Preparation of test solution for oral administration of compound 3: Weigh 21.62 mg of compound 3 into a glass bottle; add 0.628 mL of DMSO, mix well, then add 1.256 mL of Solutol HS-15, mix well, then add 10.674 mL of physiological saline, vortex mix, and sonicate to obtain a clear and transparent solution with a concentration of 1.52 mg / mL.

[0214] Example: Preparation of test solution for gavage administration of compound 8: The test solution was prepared on the same day. 16.51 mg of compound 8 was weighed into a glass bottle; 0.536 mL of DMSO was added, and after mixing, 1.071 mL of Solutol HS-15 was added, and after mixing, 9.106 mL of physiological saline was added and vortexed. The solution was then sonicated to obtain a clear and transparent solution with a concentration of 1.45 mg / mL.

[0215] 2.4 Administration:

[0216] 2.4.1 Administration of Compound 17:

[0217] Nine male SD rats were administered the drug via intravenous injection after fasting overnight. The dosage was 1 mg / kg (0.00405 mmol / kg), and the administration volume was 5 mL / kg.

[0218] Nine male SD rats were administered the drug via PO (oral administration) after fasting overnight. The dosage was 10 mg / kg (0.0405 mmol / kg) and the administration volume was 10 mL / kg.

[0219] 2.4.2 Administration of Compound 3:

[0220] Nine male SD rats were used. After fasting overnight, they were administered the drug PO at a dose of 15.2 mg / kg (0.0405 mmol / kg) in a volume of 10 mL / kg.

[0221] 2.4.3 Administration of Compound 8:

[0222] Nine male SD rats were used. After fasting overnight, they were administered the drug PO at a dose of 14.5 mg / kg (0.0405 mmol / kg) in a volume of 10 mL / kg.

[0223] 2.5 Sample Collection and Processing:

[0224] Intravenous injection sampling time points: 5 min, 15 min, 30 min, 1 h, 2 h, 4 h, 8 h, and 24 h after administration.

[0225] Data collection points after gavage administration: 15 min, 30 min, 1 h, 2 h, 4 h, 6 h, 12 h, and 24 h after administration.

[0226] Approximately 0.1 mL of blood was collected and placed in a labeled EDTA-2K anticoagulant tube. The tube was gently inverted to ensure thorough mixing of the anticoagulant (EDTA-2K) with the blood. The plasma was then separated by centrifugation within 1 hour of blood collection at 4°C, 6800g, for 6 minutes. The separated plasma was then transferred to labeled EP tubes and stored in an ultra-low temperature freezer as soon as possible until sample analysis.

[0227] Table 4. Rat pharmacokinetic data of the compounds in the examples

[0228] 3. Experimental Conclusions

[0229] The pharmacokinetic properties of compounds 3 and 8 of the present invention are superior to those of compound 17.

[0230] 3.1 Significantly improved bioavailability

[0231] The oral bioavailability of compound 3 was 98.7%, that of compound 8 was 81.6%, and that of compound 17 was 58.5%. These data indicate that compounds 3 and 8 have significantly higher bioavailability than compound 17, suggesting that their design successfully reduced the first-pass effect or metabolic loss, thus improving oral absorption efficiency. Higher bioavailability can reduce the dosage, decrease potential side effects, and improve patient compliance.

[0232] 3.2 Advantages of Exposure

[0233] AUC of compound 3, active ingredient, administered by gavage 0-t The concentration was 42524 h·ng / mL; the AUC of compound 8, the active ingredient, was determined by gavage administration. 0-t The AUC of compound 17 administered by gavage was 37930 h·ng / mL. 0-t The AUC was 29162 h·ng / mL, indicating that both compounds 3 and 8 had a higher AUC than compound 17 after direct gavage. 0-t The high levels indicate that compounds 3 and 8 can reach effective blood concentrations more quickly and maintain longer exposure, potentially enhancing efficacy.

Claims

1. A β-lactamase inhibitor, which is a compound of formula (I) or an optical isomer thereof: in, L is selected from -C(O)- and -C(O)NR. a -OC(=O)-, -(CR) a R b ) i -C(=O)O- or -OC(=O)O-; X is selected from direct bond or -(CR) c R d ) k -(CH2) n -; R 1 Selected from H, halogens, -CN, -OH, -NH2, C 1-6 Alkyl, C 3-12 Cycloalkyl, 3-12 membered heterocyclic groups, C 6-12 Aryl, 5-12 heteroaryl, -C(O)R 2 -C(O)OR 2 -C(O)NR 2 R 3 -NR 2 C(O)R 3 -NR 2 R 3 -OR 2 -OC(O)R 2 -OC(O)NR 2 R 3 -NR 2 C(O)NR 3 R 4 -NR 2 C(O)OR 3 -SR 2 -S(O)R 2 -S(O)2R 2 -S(O)NR 2 R 3 -S(O)2NR 2 R 3 or -NR 2 S(O)2R 3 The C 3-12 Cycloalkyl, 3-12 membered heterocyclic groups, C 6-12 The aryl and 5-12 heteroaryl groups are each independently and selectively coupled with one or more R groups. 5 replace; R a and R b Each is independently selected from H, halogen, or C. 1-6 Alkyl; or R a and R b The atoms connected to them combine to form C 3-6 cycloalkyl, the C 1-6 The alkyl group may optionally be substituted with one or more halogens; R c and R d Each is independently selected from H, halogen, or C. 1-6 Alkyl; or R c and R d The atoms connected to them combine to form C 3-6 cycloalkyl, the C 1-6 The alkyl group may optionally be substituted with one or more halogens; R 2 R 3 and R 4 Each is independently selected from C 1-6 Alkyl, C 3-12 Cycloalkyl, 3-12 membered heterocyclic groups, C 6-12 Aryl or 5-12 heteroaryl groups; R 5 Selected from halogens, -CN, -OH, -NH2, C 1-6 Alkyl, -C(O)R 2 -C(O)OR 2 -C(O)NR 2 R 3 -NR 2 C(O)R 3 NR 2 R 3 -OR 2 -OC(O)R 2 -OC(O)NR 2 R 3 -NR 2 C(O)NR 3 R 4 -NR 2 C(O)OR 3 -SR 2 -S(O)R 2 -S(O)2R 2 -S(O)NR 2 R 3 -S(O)2NR 2 R 3 or -NR 2 S(O)2R 3 ; m can be 1, 2, 3, or 4; n is 1, 2, 3, or 4; i can be 0, 1, 2, 3 or 4; k can be 0, 1, 2, 3 or 4.

2. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, L is selected from -OC(=O)-, -CH2C(=O)O-, -CF2C(=O)O-, -C(CH3)2C(=O)O-, -C(O)NCH3- or -OC(=O)O-; preferably, L is -OC(=O)-.

3. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, R a Selected from H, F or -CH3.

4. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, R b Selected from H, F or -CH3.

5. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, X is selected from direct bond, -CH2-, -(CH2)3-, -C(CH3)2-CH2-, -CH(CH3)-, -CH(CH3)-(CH2)2-, -CH(CH3)-(CH2)3-, -CH(C2H5)-(CH2)- or -CH(C2H5)-(CH2)3-; preferably, X is -CH(C2H5)-(CH2)-.

6. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, R c Selected from H.

7. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, R d Selected from H, -CH3, or -C2H5.

8. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, R 1 Selected from -CH3, -OCH3, -OC(O)CH3, Preferably, R 1 It is -CH3.

9. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, R 1 Selected from -C(O)N(CH3)2.

10. The β-lactamase inhibitor according to claim 1, characterized in that, In the compound of formula (I) or its optical isomer, R 2 Selected from H or -CH3.

11. The β-lactamase inhibitor according to claims 1-10, characterized in that, In the compound of formula (I) or its optical isomer, L is -OC(=O)-, X is -CH(C2H5)-(CH2)-, and R is... 1 It is -CH3.

12. The β-lactamase inhibitor according to claims 1-11, characterized in that, The Selected from 13. The β-lactamase inhibitor according to claims 1-11, characterized in that, The Selected from 14. The β-lactamase inhibitor according to claims 1-13, wherein the compound of formula (I) is selected from the following compounds:

15. A pharmaceutical composition, characterized in that, The compound or its optical isomer can be used in combination with one or more other antibiotics for the treatment of bacterial infections, said other antibiotics being selected from telbipenem, cefbufen, cefixime, ceftriaxone, cefdinir, cefpodoxime, pimecrolimus, cefaclor, cefuroxime, cefalexin, or combinations of two or more thereof; preferably, selected from telbipenem, cefbufen, cefixime, ceftriaxone, cefdinir, or cefpodoxime; more preferably, selected from telbipenem, cefbufen, or cefixime.

16. The use of any compound, optical isomer, or pharmacologically acceptable salt thereof, or the pharmaceutical composition of claim 15, in the preparation of a medicament for treating bacterial infections.

17. The application according to claim 16, wherein the bacterial infection type comprises an infection selected from: Klebsiella pneumoniae, Escherichia coli, Escherichia coli, Enterobacter cloacae, Acinetobacter baumannii, or Pseudomonas aeruginosa.

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