Bicyclo [2.1. 1] hexene compound and preparation and application thereof

Abstract

The invention discloses a bicyclo [2.1. 1] hexene compound and preparation and application thereof.The bicyclo [2.1. 1] hexene compound is obtained by taking bicyclo [1.1. 1] butanone and phosphate as starting raw materials and taking a tetrahydrofuran solution of potassium tert-butoxide as alkali through reflux and reaction at the temperature of 80 DEG C. The prepared compound has certain transpeptidase inhibitory activity, and can be used as a novel compound for inhibiting transpeptidase. The infection and diffusion of the staphylococcus aureus can be effectively inhibited.

Description

(I) Technical field

[0001] The present invention belongs to the field of biomedicine, and particularly relates to a novel bicyclo[2.1.1]hexene compound and an efficient synthesis route and antibacterial activity evaluation. (II) Background technology

[0002] Bioisostere replacement strategy plays an important role in the development of new drugs. Since phenyl groups are widely present in marketed drugs, research on bioisostere replacement based on benzene rings has always received widespread attention. However, in order to reasonably perform isosteric substitution, isosteres should not only have the same total number of outer electrons, but also be similar in terms of molecular size, shape (including bond angle, degree of hybridization), conformation, electron distribution (extreme, inductive effect, conjugation effect, charge, dipole, etc.), lipid-water distribution coefficient, chemical reactivity and hydrogen bond formation ability. Since bioisosteres are not universal, sometimes bioisosteres suitable for a certain series of compounds are not suitable for another series of compounds.

[0003] As a potential phenyl bioisostere, bicyclo[2.1.1]hexene is challenging to synthesize due to its large intrinsic molecular tension. The synthesis and development of new bicyclo[2.1.1]hexene compounds lays the foundation for the application of bicyclo skeletons in drug structure modification, which is of great significance in the field of pharmacy.

[0004] Sortase A plays a key role in the fixation of Staphylococcus aureus cell wall proteins and is considered as one of the new targets for antimicrobial drugs. By inhibiting Sortase A, the adhesion and colonization of pathogens can be effectively inhibited, thereby limiting the spread of infection. The development of new bicyclo[2.1.1]hexene compounds with Sortase A activity inhibition provides a potential new strategy for the development of new antimicrobial agents. (III) Summary of the invention

[0005] The invention provides a bicyclo[2.1.1]hexene compound and preparation and application thereof. The invention uses bicyclo[1.1.0]butanone and phosphate as starting materials, uses a tetrahydrofuran solution of potassium tert-butoxide as a base, and refluxes at 80°C to obtain a bicyclo[2.1.1]hexene compound. The prepared compound has a certain transpeptidase inhibitory activity and can effectively inhibit the infection and spread of Staphylococcus aureus.

[0006] The technical solution adopted by the present invention is:

[0007] In the first aspect, the present invention provides a multi-substituted bicyclo[2.1.1]hexene compound represented by formula (I):

[0008]

[0009] In formula (I), when R 1 =R 2 Time: R 1 , R 2 Each is independently phenyl, 4-tert-butylphenyl, 4-phenylphenyl, 4-trifluoromethoxyphenyl, 4-fluorophenyl, 4-trifluoromethylphenyl, 2-naphthyl;

[0010] In formula (I), when R 1 ≠R 2 Time: R 1 is phenyl, R 2 is one of 4-methylphenyl, 4-tert-butylphenyl, 4-phenylphenyl, 4-methoxyphenyl, 4-trifluoromethoxyphenyl, 4-methylthiophenyl, 4-trimethylsilylphenyl, 3,4-dimethylphenyl, 4-chlorophenyl, 4-bromophenyl, 4-trifluoromethylphenyl, 3-methylphenyl, 3-phenylphenyl, 3-methoxyphenyl, 3-chlorophenyl, 2-naphthyl, 2-pyridyl, 2-thienyl, 2-bromo-5-thienyl, 2-furyl, and 2-bromo-5-furyl; R 2 is phenyl, R 1 It is one of 4-methylphenyl, 4-phenylphenyl, 4-trifluoromethoxyphenyl, 4-trifluoromethylphenyl and 3-phenylphenyl.

[0011] Further, the bicyclo[2.1.1]hexene compound is one of the following:

[0012]

[0013]

[0014]

[0015] In a second aspect, the present invention provides a method for preparing a bicyclo[2.1.1]hexene compound represented by formula (I), wherein the reaction formula of the method is as follows:

[0016]

[0017] In formula (II), when R 1 =R 2 Time: R 1 , R 2 Each is independently phenyl, 4-tert-butylphenyl, 4-phenylphenyl, 4-trifluoromethoxyphenyl, 4-fluorophenyl, 4-trifluoromethylphenyl, 2-naphthyl;

[0018] When R 1 ≠R 2 Time: R 1 is phenyl, R 2is one of 4-methylphenyl, 4-tert-butylphenyl, 4-phenylphenyl, 4-methoxyphenyl, 4-trifluoromethoxyphenyl, 4-methylthiophenyl, 4-trimethylsilylphenyl, 3,4-dimethylphenyl, 4-chlorophenyl, 4-bromophenyl, 4-trifluoromethylphenyl, 3-methylphenyl, 3-phenylphenyl, 3-methoxyphenyl, 3-chlorophenyl, 2-naphthyl, 2-pyridyl, 2-thienyl, 2-bromo-5-thienyl, 2-furyl, and 2-bromo-5-furyl; R 2 is phenyl, R 1 It is one of 4-methylphenyl, 4-phenylphenyl, 4-trifluoromethoxyphenyl, 4-trifluoromethylphenyl, and 3-phenylphenyl;

[0019] In formula (I), R 1 Same as R in formula (II) 1 In formula (I), R 2 Same as R in formula (II) 2 ;

[0020] The preparation method comprises the following steps: placing compound (II) in a dry reaction tube at room temperature, adding tetrahydrofuran (THF), stirring and dissolving; adding compound (III), dropping potassium tert-butoxide, and reacting under magnetic stirring and reflux at 80° C., monitoring the reaction progress by thin layer chromatography (TLC) using a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 as a developing agent; after the reaction is completed, removing the magnetic stirrer from the reaction solution, adding a saturated ammonium chloride solution to the reaction solution for quenching, and then extracting the reaction mixture with ethyl acetate for 1-3 times, combining the obtained organic phases, and drying them with anhydrous sodium sulfate; the dried organic phases The phase is filtered to remove sodium sulfate, and the solvent is removed by rotary evaporation under reduced pressure to obtain a crude product; the crude product is purified by a silica gel chromatography column, using petroleum ether and ethyl acetate in a volume ratio of 10:1 as an eluent, the elution volume is 5 to 10 column volumes (preferably 7 column volumes), and the elution rate is 5 to 15 mL / min (preferably 10 mL / min); during the elution process, a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 is used as a developing solvent for TLC monitoring, and the eluted fractions with Rf values ​​of 0.7 to 0.8 are collected, and the solvent is removed by rotary evaporation under reduced pressure to obtain a bicyclo[2.1.1]hexene compound represented by formula (I).

[0021] Furthermore, the volume amount of tetrahydrofuran is 10 mL / mmol based on the amount of compound (II); the molar ratio of compound (II) to compound (III) and potassium tert-butoxide is 1:2:2.

[0022] The present invention also provides a use of the bicyclo[2.1.1]hexene compound in the preparation of a transaminase activity inhibitor.

[0023] The present invention also provides an application of the bicyclo[2.1.1]hexene compound in preparing an antibacterial agent for Staphylococcus aureus.

[0024] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in: the present invention provides a new bicyclo [2.1.1] hexene compound, the compound has a stable structure and is not easy to degrade, and the synthetic method adopted is green and simple, suitable for large-scale preparation, and has excellent application prospects. The bicyclo [2.1.1] hexene compound of the present invention can effectively inhibit the activity of transaminase, and can be used to inhibit the infection of Staphylococcus aureus. (IV) Description of the drawings

[0025] Figure 1 , Compound (I-1) 1 H NMR spectra (a) and 13 C NMR spectrum (b).

[0026] Figure 2 , Compound (I-9) 1 H NMR spectra (a) and 13 C NMR spectrum (b).

[0027] Figure 3 , Compound (I-11) 1 H NMR spectra (a) and 13 C NMR spectrum (b).

[0028] Figure 4 , Compound (I-17) 1 H NMR spectra (a) and 13 C NMR spectrum (b).

[0029] Figure 5 , Compound (I-30) 1 H NMR spectra (a) and 13 C NMR spectrum (b). (V) Specific implementation methods

[0030] The present invention is further explained below in conjunction with specific examples, but the specific examples do not limit the present invention in any way. Unless otherwise specified, the reagents and methods involved in the examples are all commonly used reagents and methods in the art.

[0031] Among them, compound (III) was obtained through commercial purchase, and the preparation of compound (II) refers to the literature J.Am.Chem.Soc.2023,145,21152-21158.

[0032] The room temperature of the present invention is 25-30°C.

[0033] Example 1: Preparation of 1,3-diphenylbicyclo[2.1.1]hex-2-ene-2-carboxylic acid ethyl ester (I-1):

[0034]

[0035] At room temperature, 3-phenylbicyclo[1.1.0]butylbenzophenone (Ⅱ-1, 46.8 mg, 0.20 mmol) and tetrahydrofuran (2 mL) were added to a 5 mL dry reaction tube, stirred and dissolved, and then ethyl 2-(diethoxyphosphonyl)acetate (Ⅲ-1, 89.6 mg, 0.40 mmol) was added, and then potassium tert-butoxide (0.40 ml, 0.40 mmol) was added dropwise, and refluxed at 80 ° C for 6 hours under magnetic stirring. The reaction was monitored with petroleum ether and ethyl acetate in a volume ratio of 10:1 as a developing agent. After the reaction was completed, the magnetic stirrer was removed from the reaction solution, and a saturated ammonium chloride solution was added to the reaction solution for quenching. Then, the reaction mixture was extracted three times with ethyl acetate, and the obtained organic phases were combined and dried with anhydrous sodium sulfate. The dried organic phase was filtered to remove sodium sulfate, and the solvent was removed by rotary evaporation under reduced pressure to obtain a crude product. The crude product was separated by chromatography on a silica gel column (silica gel particle size 200-300 mesh, column height 42 cm, diameter 15 mm), and the eluent was V 石油醚 :V 乙酸乙酯 =10:1, elution volume 7 column volumes, elution rate 10mL / min, TLC spot plate monitoring with petroleum ether and ethyl acetate in a volume ratio of 10:1 as the developing solvent, collect the effluent with an Rf value of 0.7, and rotary evaporate until no liquid flows out to obtain 54.0mg of white solid, namely 1,3-diphenylbicyclo[2.1.1]hex-2-ene-2-carboxylic acid ethyl ester (Ⅰ-1), the yield is 89%, and the 1 H NMR Figure 1 Middle a, 13 C NMR Figure 1 Middle b. 1 H NMR (500MHz, CDCl3) δ7.65-7.67(m,2H),7.36-7.40(m,2H),7.30-7.34(m,3H),7.21-7.25(m,3H),3.88(q ,J=7.0Hz,2H),3.17-3.19(m,3H),2.82(ddd,J1=4.0Hz,J2=2.5Hz,J3=1.5Hz,2H),0.81(t,J=7.0Hz,3H). 13C NMR (125MHz, CDCl3) δ165.4,163.8,141.6,140.0,134.1,128.6,128.1,127.9,127.8,126.3,126.2,66.7,60.2,59.7,43.9,13.4.HRMS(ESI-TOF):m / z calc'd for C 21 H 21 O2(M+H) + :305.1536, found 305.1534.

[0036] Using the same method, (II-1) and (III-1) in the preparation process of compound (I-1) were replaced according to the corresponding substituents in Table 1 to prepare compounds (I-2) to (I-33), respectively. The NMR data are shown in Table 1.

[0037] Table 1 Structural data of compounds Ⅰ-1-Ⅰ-33

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] Example 2: Evaluation of Compounds on Sortase A Transpeptidase Activity

[0049] 1. Study on the activity of compound Ⅰ on sortase A in Staphylococcus aureus (DSM 20231).

[0050] (1) Sample preparation:

[0051] 1) Preparation of substrate solution: Weigh 1.7 mg of substrate LPATG (purchased from Shanghai Jier Biochemical Co., Ltd.), add 781.66 μL DMSO to fully dissolve, then add 7.0349 mL pure water to prepare a substrate solution with a final concentration of 250 μM. The final concentration of the substrate in each well (96-well plate) during the experiment was 25 μM.

[0052] 2) Compound solution preparation: Compounds I-1 to I-33 were dissolved in DMSO to prepare 45 μM compound solutions.

[0053] 3) Buffer solution: pH 7.5, 50 mM Tris-HCl buffer containing 150 mM NaCl and 5 mM CaCl2.

[0054] 4) Preparation of Buffer-E solution: Take out 187.5 μL of Sortase A stored at -80°C and add it to 11.8 mL of Buffer solution to prepare working buffer solution (Buffer-E solution).

[0055] (2) Sortase A activity assay:

[0056] The 96-well plate was divided into experimental group, control group A and control group B.

[0057] Experimental group: 80 μL of prepared Buffer-E solution and 10 μL of compound solution were added to each well.

[0058] Control group A (i.e., without adding transferase): 80 μL Buffer-E solution and 10 μL Buffer solution were added to each well.

[0059] Control group B: Add 90 μL of Buffer solution to each well.

[0060] After the 96-well plate was pre-incubated at 37°C for 10 minutes, 10 μL of substrate solution was added to each well, the final concentration of Sortase A in each well was 1.25 μM, and the final concentration of the compound was 4.5 μM, and the initial fluorescence intensity (excitation wavelength λ1 = 305 nm, emission wavelength λ2 = 460 nm) was immediately measured and recorded as the fluorescence intensity at 0 minutes. The 96-well plate was then incubated at 37°C for 60 minutes and the fluorescence intensity was measured again. The change in fluorescence intensity indicates the amount of product generated by substrate hydrolysis, which is used to evaluate the inhibitory effect of the compound on Sortase A activity. Each group of experiments was repeated three times.

[0061] The calculation formula of Sortase A activity inhibition rate is:

[0062] Sortase A activity inhibition rate = 100-(F 60 min -F0min +F 不加转肽酶 ) / F 加转肽酶 ×100

[0063] 2. Conclusion: The experimental results show that when the final concentration of the compound is 4.5 μM, compounds I-15, I-18, and Ⅰ-24 have good inhibitory activity against Sortase A of Staphylococcus aureus, among which compounds I-1, Ⅰ-12, Ⅰ-13, Ⅰ-14, Ⅰ-16, Ⅰ-17, Ⅰ-22, and I-23 have an inhibition rate of more than 22% on the activity of Sortase A of Staphylococcus aureus.

[0064] Table 2 Inhibition rate of bicyclo[2.1.1]hexene compounds on Sortase A (4.5 μM)

[0065]

[0066]

[0067]

[0068]

[0069]

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A polysubstituted bicyclo[2.1.1]hexene compound represented by formula (I): In formula (I), when R 1 =R 2 Time: R 1 , R 2 Each is independently phenyl, 4-tert-butylphenyl, 4-phenylphenyl, 4-trifluoromethoxyphenyl, 4-fluorophenyl, 4-trifluoromethylphenyl, 2-naphthyl; When R 1 ≠R 2 Time: R 1 is phenyl, R 2 is one of 4-methylphenyl, 4-tert-butylphenyl, 4-phenylphenyl, 4-methoxyphenyl, 4-trifluoromethoxyphenyl, 4-methylthiophenyl, 4-trimethylsilylphenyl, 3,4-dimethylphenyl, 4-chlorophenyl, 4-bromophenyl, 4-trifluoromethylphenyl, 3-methylphenyl, 3-phenylphenyl, 3-methoxyphenyl, 3-chlorophenyl, 2-naphthyl, 2-pyridyl, 2-thienyl, 2-bromo-5-thienyl, 2-furyl, and 2-bromo-5-furyl; R 2 is phenyl, R 1 It is one of 4-methylphenyl, 4-phenylphenyl, 4-trifluoromethoxyphenyl, 4-trifluoromethylphenyl and 3-phenylphenyl.

2. The bicyclo[2.1.1]hexene compound according to claim 1, characterized in that The bicyclo[2.1.1]hexene compound is one of the following:

3. A method for preparing the bicyclo[2.1.1]hexene compound according to claim 1, characterized in that: The method comprises the following steps: placing compound (II) in a dry reaction tube at room temperature, adding tetrahydrofuran, stirring and dissolving; adding compound (III), dropping potassium tert-butoxide, and reacting under magnetic stirring and reflux at 80°C, monitoring the reaction progress by thin layer chromatography using a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 as a developing agent; after the reaction is completed, removing the magnetic stirrer from the reaction solution, adding a saturated ammonium chloride solution to the reaction solution for quenching, extracting the reaction mixture with ethyl acetate for 1-3 times, combining the obtained organic phases, and drying with anhydrous sodium sulfate; drying The dried organic phase is filtered to remove sodium sulfate, and the solvent is removed by rotary evaporation under reduced pressure to obtain a crude product; the crude product is purified by a silica gel chromatography column, using petroleum ether and ethyl acetate in a volume ratio of 10:1 as an eluent, the elution volume is 5 to 10 column volumes, and the elution rate is 5 to 15 mL / min; during the elution process, a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 is used as a developing solvent for thin layer chromatography monitoring, and the eluted fractions with Rf values ​​of 0.7 to 0.8 are collected, and the solvent is removed by rotary evaporation under reduced pressure to obtain a bicyclo[2.1.1]hexene compound represented by formula (I); In formula (II), when R 1 =R 2 Time: R 1 , R 2 Each is independently phenyl, 4-tert-butylphenyl, 4-phenylphenyl, 4-trifluoromethoxyphenyl, 4-fluorophenyl, 4-trifluoromethylphenyl, 2-naphthyl; When R 1 ≠R 2 Time: R 1 is phenyl, R 2 is one of 4-methylphenyl, 4-tert-butylphenyl, 4-phenylphenyl, 4-methoxyphenyl, 4-trifluoromethoxyphenyl, 4-methylthiophenyl, 4-trimethylsilylphenyl, 3,4-dimethylphenyl, 4-chlorophenyl, 4-bromophenyl, 4-trifluoromethylphenyl, 3-methylphenyl, 3-phenylphenyl, 3-methoxyphenyl, 3-chlorophenyl, 2-naphthyl, 2-pyridyl, 2-thienyl, 2-bromo-5-thienyl, 2-furyl, and 2-bromo-5-furyl; R 2 is phenyl, R 1 It is one of 4-methylphenyl, 4-phenylphenyl, 4-trifluoromethoxyphenyl, 4-trifluoromethylphenyl, and 3-phenylphenyl; In formula (I), R 1 Same as R in formula (II) 1 In formula (I), R 2 Same as R in formula (II) 2 .

4. The preparation method according to claim 3, characterized in that: The volume amount of tetrahydrofuran used is 10 mL / mmol based on the amount of compound (II); the molar ratio of compound (II) to compound (III) and potassium tert-butoxide is 1:2:

2.

5. Use of the bicyclo[2.1.1]hexene compound according to claim 1 in the preparation of a transaminase activity inhibitor.

6. Use of the bicyclo[2.1.1]hexene compound according to claim 1 in the preparation of an antibacterial agent for Staphylococcus aureus.

Images