Tetrahydroisoquinoline derivative antibacterial agent, preparation method thereof, composition containing same, pharmaceutical preparation and application of the three

Abstract

The present invention belongs to the field of pharmaceutical chemistry technology, and specifically relates to tetrahydroisoquinoline derivative antibacterial agents, preparation methods thereof, compositions containing the same, pharmaceutical preparations, and applications thereof. The invention relates to a compound having a structure as shown in Formula I or a pharmaceutically acceptable salt thereof, or at least one of a solvent compound, enantiomer, diastereomer, and tautomer of a compound as shown in Formula I or a pharmaceutically acceptable salt thereof; wherein R 1 and R 2 The tetrahydroisoquinoline derivative antibacterial agents are selected from hydrogen or chlorine and are different. They exhibit excellent and broad-spectrum antibacterial activity against different strains without changing the permeability of bacterial cell membranes. The MIC values ​​for various tested strains remain below 0.5 μg / mL, demonstrating their effectiveness against drug-resistant bacteria.

Description

Technical Field

[0001] The present invention belongs to the technical field of pharmaceutical chemistry, and specifically relates to tetrahydroisoquinoline derivative antibacterial agents, preparation methods thereof, compositions containing the same, pharmaceutical preparations, and applications of the three. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Antibiotics are the cornerstone of modern medicine and a powerful weapon in humanity's long and arduous struggle against bacteria. They have effectively cured infectious diseases caused by numerous pathogens and reduced associated mortality rates. However, antibiotics are also a double-edged sword, with the consequent widespread and rapid spread of antibiotic resistance genes (ARGs) in bacteria worldwide, triggering the significant public health problems of antibiotic resistance (AMR) and tolerance.

[0004] The mechanisms of bacterial resistance include: (1) production of enzymes that inactivate and modify antimicrobial drugs; (2) modification of antimicrobial drug targets; (3) changes in bacterial cell membrane permeability; (4) bacterial active efflux mechanisms; (5) changes in metabolic pathways; and (6) biofilm formation. Furthermore, most antimicrobial drugs approved for marketing in recent years have a narrow antimicrobial spectrum, similar to the mechanism of action of traditional antibiotics that inhibit bacterial protein synthesis. This can easily induce bacterial resistance and thus reduce the level of antimicrobial treatment. These factors make the development of new broad-spectrum antimicrobial drugs urgent.

[0005] Existing antimicrobial agents need to pass through the bacterial cell membrane to reach their target sites in order to exert their activity. However, bacteria can develop drug resistance by reducing the permeability of the outer membrane, and antimicrobial agents cannot enter the bacterial cell through the porin channel, thus becoming ineffective. Summary of the Invention

[0006] To address the deficiencies of the prior art, the present invention provides tetrahydroisoquinoline derivative antimicrobial agents, methods for their preparation, compositions containing them, pharmaceutical preparations, and applications thereof. These antimicrobial agents exhibit excellent broad-spectrum antimicrobial activity against different strains without altering bacterial cell membrane permeability. MIC values ​​for a variety of tested strains remained below 0.5 μg / mL, demonstrating their effectiveness against drug-resistant bacteria.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] In a first aspect, a tetrahydroisoquinoline derivative antibacterial agent having a structure as shown in Formula I or a pharmaceutically acceptable salt thereof, or at least one of a solvent compound, enantiomer, diastereomer, and tautomer of a compound as shown in Formula I or a pharmaceutically acceptable salt thereof;

[0009]

[0010] Where R 1 and R 2 are each selected from hydrogen or chlorine and are different.

[0011] The structure shown in Formula I is specifically any one of Compound I-1 and Compound I-2:

[0012]

[0013] In a second aspect, a method for preparing the tetrahydroisoquinoline derivative antibacterial agent as described in the first aspect comprises the following steps:

[0014]

[0015] a. Compound 1 was dissolved in toluene, and aminoacetaldehyde dimethyl acetal was added to reflux reaction. After the reaction, sodium borohydride was added to extract and react to obtain compound 2;

[0016] b. Compound 2 was dissolved in dichloromethane, and triethylamine, p-toluenesulfonyl chloride and 4-dimethylaminopyridine were added to react to obtain compound 3;

[0017] c. Compound 3 and anhydrous aluminum chloride were dissolved in dichloromethane and reacted under nitrogen to obtain compound 4;

[0018] d. Compound 4 was dissolved in glacial acetic acid, and sodium cyanoborohydride was added to react to obtain compound 5;

[0019] e. Compound 5 and cesium carbonate were dissolved in acetonitrile, and bromodecane was added under nitrogen protection and refluxed to obtain compound 6;

[0020] f. Compound 6, sodium tert-butoxide, and N-Boc-piperazine were dissolved in toluene, and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine and bis(dibenzylideneacetone)palladium were added, and the mixture was reacted under nitrogen to obtain compound 7;

[0021] g. Compound 7 was dissolved in dichloromethane, and trifluoroacetic acid was added to react to obtain a tetrahydroisoquinoline derivative antibacterial agent having the structure shown in Formula I.

[0022] Preferably, in step a, the reaction is carried out under reflux at 119-121° C. for 5.9-6.1 h, and sodium borohydride is added and reacted at room temperature for 0.9-1.1 h.

[0023] Preferably, in step b, the reaction is carried out at room temperature for 0.9 to 1.1 hours.

[0024] Preferably, in step c, the reaction is carried out at room temperature for 11.9 to 12.1 hours under nitrogen protection, and after the reaction is completed, a saturated sodium bicarbonate solution is added dropwise at 0° C. to quench the reaction.

[0025] Preferably, in step d, the reaction is carried out at room temperature for 1.9 to 2.1 hours, and after the reaction, the pH is adjusted to acidic to precipitate compound 5.

[0026] Preferably, in step e, the reaction is refluxed at 84.9-85.1° C. for 11.9-12.1 hours.

[0027] Preferably, in step f, the reaction is carried out at 99.9-101.1° C. for 11.9-12.1 h under nitrogen protection.

[0028] Preferably, in step g, the reaction is carried out at room temperature for 0.49 to 0.51 h, and the pH is adjusted to alkaline after the reaction.

[0029] In a third aspect, a composition comprises the tetrahydroisoquinoline derivative antibacterial agent as described in the first aspect.

[0030] In a fourth aspect, a pharmaceutical preparation comprises the tetrahydroisoquinoline derivative antibacterial agent as described in the first aspect and pharmaceutically acceptable excipients.

[0031] Preferably, the pharmaceutically acceptable excipients include at least one of a solvent, a disintegrant, a flavoring agent, a preservative, a colorant and a binder.

[0032] Preferably, the dosage form of the pharmaceutical preparation includes injection, tablet, pill, capsule, suspension or emulsion.

[0033] In a fifth aspect, use of the tetrahydroisoquinoline derivative antibacterial agent as described in the first aspect and / or the composition as described in the third aspect and / or the pharmaceutical preparation as described in the fourth aspect in the preparation of antibacterial products.

[0034] Preferably, the antimicrobial product comprises an antimicrobial drug.

[0035] Preferably, the target bacteria of the antibacterial product include Gram-positive bacteria or Gram-negative bacteria.

[0036] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:

[0037] Tetrahydroisoquinoline derivative antibacterial agents exhibit excellent and broad-spectrum antibacterial activity against different types of strains. The MIC values ​​for a variety of test strains consisting of Gram-positive sensitive bacteria, Gram-positive resistant bacteria, and Gram-negative bacteria are maintained below 0.5μg / mL. In particular, the MIC value for Bacillus pumilus CMCC63202 is as low as 0.0078μg / mL, making it a broad-spectrum antibacterial agent.

[0038] By adding the hydrophobic fluorescent dye NPN and monitoring the changes in fluorescence intensity, a series of experimental results were obtained. It was found that tetrahydroisoquinoline derivative antibacterial agents had no effect on outer membrane permeability at their MIC and 1 / 2MIC concentrations, indicating that the excellent antibacterial activity of tetrahydroisoquinoline derivative antibacterial agents does not rely on the outer membrane permeability mechanism. By adding diSC35 and continuously monitoring the changes in the intensity of the fluorescence signal before and after the addition of the compound to determine whether the compound would affect the bacterial inner membrane proton gradient, it was found that tetrahydroisoquinoline derivatives had no effect on the inner membrane proton gradient at their MIC and 1 / 2MIC concentrations, indicating that the excellent antibacterial activity of tetrahydroisoquinoline derivatives does not rely on the inner and outer membrane permeability mechanism. Because tetrahydroisoquinoline derivatives do not rely on bacterial cell membrane permeabilization to exert their antibacterial activity, they can effectively fight drug-resistant bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0040] Figure 1 The results of the test on the bacterial outer membrane permeability of compound I2;

[0041] Figure 2 This is the result of measuring the effect of compound I2 on the proton gradient of the bacterial inner membrane. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0043] Example 1

[0044] Preparation of N-(4-bromo-3-chloro)-2,2-dimethoxyethyl-1-amine (Compound 2-1):

[0045]

[0046] 4-Bromo-3-chlorobenzaldehyde (Compound 1-1, 3.0 g, 13.7 mmol) was dissolved in toluene (25 mL), and aminoacetaldehyde dimethyl acetal (2.9 g, 27.3 mmol) was added. The temperature was raised to 120°C and refluxed for 6 h. Since the reaction could not be monitored by TLC, the reaction was quenched directly with water (50 mL) after 6 h and transferred to a separatory funnel. An appropriate amount of dichloromethane was added for extraction. This was repeated three times. The organic phases were combined, washed with water (50 mL × 2) and brine (50 mL), and the organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The residue was dissolved in ethanol (25 mL), and sodium borohydride (1.6 g, 41.0 mmol) was added in small portions. The reaction was allowed to react at room temperature for 1 h. The reaction was complete when monitored by TLC. The reaction was quenched by adding water (50 mL) and transferred to a separatory funnel. Extraction was performed with an appropriate amount of ethyl acetate. This was repeated three times. The organic phases were combined and washed with water (50 mL x 2) and brine (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 2-1 in a yield of 78.4%.

[0047] Preparation of N-(4-bromo-3-chloro)-N-(2,2-dimethoxyethyl)-4-toluenesulfonamide (Compound 3-1):

[0048]

[0049] Compound 2-1 (3.3 g, 10.8 mmol) was resuspended in dichloromethane (25 mL), and triethylamine (3.3 g, 32.3 mmol), p-toluenesulfonyl chloride (3.1 g, 16.1 mmol), and 4-dimethylaminopyridine (0.2 g, 1.6 mmol) were added. The reaction was allowed to react at room temperature for 1 h. TLC monitored the reaction to be complete. The reaction solution was transferred to a separatory funnel and extracted with water (50 mL) and an appropriate amount of dichloromethane. This was repeated three times. The organic phases were combined and washed with water (50 mL × 2) and brine (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 3-1 in a yield of 87.4%.

[0050] Preparation of 6-bromo-7-chloroisoquinoline (Compound 4-1):

[0051]

[0052] Compound 4-1 (4.4 g, 9.4 mmol) was placed in a double-necked flask, anhydrous aluminum chloride (5.6 g, 42.3 mmol) was added, and nitrogen was immediately applied. Dichloromethane (50 mL) was added to the system and the reaction was allowed to react at room temperature for 12 h. TLC monitored the reaction to be complete. The double-necked flask was placed in a cold trap and cooled to 0°C. Saturated sodium bicarbonate solution was slowly added dropwise to quench the reaction. The mixture was then transferred to a separatory funnel and extracted with an appropriate amount of dichloromethane. This was repeated three times. The organic phases were combined, washed with water (50 mL × 2) and brine (50 mL), and the organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 4-1 in a yield of 68.4%.

[0053] Preparation of 6-bromo-7-chloro-1,2,3,4-tetrahydroisoquinoline (Compound 5-1):

[0054]

[0055] Compound 4-1 (1 g, 4.1 mmol) was placed in a round-bottom flask, glacial acetic acid (100 mL) was added, and the mixture was stirred at room temperature until dissolved. Sodium cyanoborohydride (0.9 g, 13.5 mmol) was then added in small, multiple batches. The mixture was stirred at room temperature for 2 h. TLC confirmed the reaction was complete. The reaction solution was poured into ice water (50 mL), cooled, and stirred for 1 h. The solution was then basified to pH 10 with 40% NaOH solution. The solution was then transferred to a separatory funnel and extracted with an appropriate amount of dichloromethane. This was repeated three times. The organic phases were combined, washed with water (50 mL x 2) and brine (50 mL), dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The residue was dissolved in a minimum amount of dichloromethane and acidified dropwise with dilute hydrochloric acid until a large amount of white solid precipitated. The solution was then diluted with petroleum ether, filtered under reduced pressure, and dried to obtain a white solid. Compound 5-1 was used directly in the next step without purification, with a yield of 92.6%.

[0056] Preparation of 6-bromo-7-chloro-2-decyl-1,2,3,4-tetrahydroisoquinoline (Compound 6-1):

[0057]

[0058] Compound 5-1 (0.2 g, 1.0 mmol) and cesium carbonate (0.6 g, 2.0 mmol) were weighed and placed in a double-necked flask under nitrogen protection. Bromodecane (0.4 g, 2.0 mmol) and acetonitrile (12 mL) were slowly added, and the temperature was raised to 85°C and refluxed for 12 h. TLC monitoring showed that the reaction was almost complete. The reaction solution was evaporated to dryness under reduced pressure, and water (50 mL) and an appropriate amount of dichloromethane were added for extraction. This was repeated three times, and the organic phases were combined and washed with water (50 mL × 2) and brine (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 6-1 in a yield of 63.8%.

[0059] Preparation of tert-butyl-4-(7-chloro-2-decyl-1,2,3,4-tetrahydroisoquinoline)-piperazinyl-1-carboxylate (Compound 7-1):

[0060]

[0061] Compound 6-1 (0.2 g, 0.6 mmol) was placed in a two-necked flask, and sodium tert-butoxide (0.1 g, 1.1 mmol) and N-Boc-piperazine (0.2 g, 1.1 mmol) were added under nitrogen. BINAP (0.011 g, 0.017 mmol) and bis(dibenzylideneacetone)palladium (0.003 g, 0.006 mmol) were added to another two-necked flask under nitrogen. Toluene (10 mL) was added and stirred for 10 min. The mixture was then transferred to the two-necked flask containing compound 6-1, taking care to avoid contact with air during the transfer. The temperature was raised to 100°C and the reaction was allowed to proceed for 12 h. TLC monitoring indicated that the reaction was nearly complete. The reaction solution was cooled to room temperature and transferred to a separatory funnel. Extraction was performed with water (50 mL) and an appropriate amount of ethyl acetate. This was repeated three times. The organic phases were combined and washed with water (50 mL x 2) and brine (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 7-1 with a yield of 67.3%.

[0062] Preparation of compound I1:

[0063]

[0064] Compound 7-1 (0.2 g, 0.4 mmol) was dissolved in dichloromethane (9 mL), and trifluoroacetic acid (0.9 g, 7.9 mmol) was added dropwise. The mixture was stirred at room temperature for 1 h. TLC was used to monitor the reaction until complete. The reaction solution was evaporated to dryness under reduced pressure, and 40% NaOH aqueous solution (50 mL) and an appropriate amount of dichloromethane were added for extraction. This was repeated three times. The organic phases were combined, washed with water (50 mL × 2) and brine (50 mL), and the organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by thin-layer chromatography to obtain compound I1 in a yield of 65.8%.

[0065] Example 2

[0066] Preparation of N-(4-bromo-2-chloro)-2,2-dimethoxyethyl-1-amine (Compound 2-2):

[0067]

[0068] 4-Bromo-2-chlorobenzaldehyde (Compound 1-2, 3.0 g, 13.7 mmol) was dissolved in toluene (25 mL), and aminoacetaldehyde dimethyl acetal (2.9 g, 27.3 mmol) was added. The temperature was raised to 120°C and refluxed for 6 h. Since the reaction could not be monitored by TLC, the reaction was quenched directly with water (50 mL) after 6 h and transferred to a separatory funnel. An appropriate amount of dichloromethane was added for extraction. This was repeated three times. The organic phases were combined, washed with water (50 mL × 2) and brine (50 mL), and the organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The residue was dissolved in ethanol (25 mL), and sodium borohydride (1.6 g, 41.0 mmol) was added in batches according to the principle of small amounts and multiple times. The reaction was allowed to react at room temperature for 1 h. The reaction was complete when monitored by TLC. The reaction was quenched by adding water (50 mL) and transferred to a separatory funnel. Extraction was performed with an appropriate amount of ethyl acetate. This was repeated three times. The organic phases were combined and washed with water (50 mL x 2) and brine (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 2-1 in a yield of 77.8%.

[0069] Preparation of N-(4-bromo-2-chloro)-N-(2,2-dimethoxyethyl)-4-toluenesulfonamide (Compound 3-2):

[0070]

[0071] Compound 2-2 (3.3 g, 10.8 mmol) was resuspended in dichloromethane (25 mL), and triethylamine (3.3 g, 32.3 mmol), p-toluenesulfonyl chloride (3.1 g, 16.1 mmol), and 4-dimethylaminopyridine (0.2 g, 1.6 mmol) were added. The reaction was allowed to react at room temperature for 1 h. TLC monitored the reaction to be complete. The reaction solution was transferred to a separatory funnel and extracted with water (50 mL) and an appropriate amount of dichloromethane. This was repeated three times. The organic phases were combined and washed with water (50 mL × 2) and brine (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 3-2 in a yield of 86.7%.

[0072] Preparation of 6-bromo-8-chloroisoquinoline (Compound 4-2):

[0073]

[0074] Compound 3-2 (4.4 g, 9.4 mmol) was placed in a double-necked flask, anhydrous aluminum chloride (5.6 g, 42.3 mmol) was added, and nitrogen was immediately applied. Dichloromethane (50 mL) was added to the system and the reaction was allowed to react at room temperature for 12 h. TLC monitored the reaction to be complete. The double-necked flask was placed in a cold trap and cooled to 0°C. Saturated sodium bicarbonate solution was slowly added dropwise to quench the reaction. The mixture was then transferred to a separatory funnel and extracted with an appropriate amount of dichloromethane. This was repeated three times. The organic phases were combined, washed with water (50 mL × 2) and brine (50 mL), and the organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 4-2 in a yield of 67.1%.

[0075] Preparation of 6-bromo-8-chloro-1,2,3,4-tetrahydroisoquinoline (Compound 5-2):

[0076]

[0077] Compound 4-2 (1 g, 4.1 mmol) was placed in a round-bottom flask, glacial acetic acid (100 mL) was added, and the mixture was stirred at room temperature until dissolved. Sodium cyanoborohydride (0.9 g, 13.5 mmol) was then added in small, multiple batches. The mixture was stirred at room temperature for 2 h. TLC monitored the reaction to be complete. The reaction solution was poured into ice water (50 mL), cooled, and stirred for 1 h. It was then basified to pH 10 with 40% NaOH solution, transferred to a separatory funnel, and extracted with an appropriate amount of dichloromethane. This was repeated three times. The organic phases were combined, washed with water (50 mL × 2) and brine (50 mL), dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The residue was dissolved in a minimum amount of dichloromethane and acidified dropwise with dilute hydrochloric acid until a large amount of white solid precipitated. The mixture was then diluted with petroleum ether, filtered under reduced pressure, and dried to obtain a white solid. Compound 5-2 was used directly in the next step without purification, with a yield of 91.8%.

[0078] Preparation of 6-bromo-8-chloro-2-decyl-1,2,3,4-tetrahydroisoquinoline (Compound 6-2):

[0079]

[0080] Compound 5-2 (0.2 g, 1.0 mmol) and cesium carbonate (0.6 g, 2.0 mmol) were weighed and placed in a double-necked flask under nitrogen protection. Bromodecane (0.4 g, 2.0 mmol) and acetonitrile (12 mL) were slowly added, and the temperature was raised to 85°C and refluxed for 12 h. TLC monitoring showed that the reaction was almost complete. The reaction solution was evaporated to dryness under reduced pressure, and water (50 mL) and an appropriate amount of dichloromethane were added for extraction. This was repeated three times, and the organic phases were combined and washed with water (50 mL × 2) and brine (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 6-2 in a yield of 62.9%.

[0081] Preparation of tert-butyl-4-(8-chloro-2-decyl-1,2,3,4-tetrahydroisoquinoline)-piperazinyl-1-carboxylate (Compound 7-2):

[0082]

[0083] Compound 6-2 (0.2 g, 0.6 mmol) was placed in a two-necked flask, and sodium tert-butoxide (0.1 g, 1.1 mmol) and N-Boc-piperazine (0.2 g, 1.1 mmol) were added under nitrogen. BINAP (0.011 g, 0.017 mmol) and bis(dibenzylideneacetone)palladium (0.003 g, 0.006 mmol) were added to another two-necked flask under nitrogen. Toluene (10 mL) was added and stirred for 10 min. The mixture was then transferred to the two-necked flask containing compound 6-2, taking care to avoid contact with air during the transfer. The temperature was raised to 100°C and the reaction was allowed to proceed for 12 h. TLC monitoring indicated that the reaction was nearly complete. The reaction solution was cooled to room temperature and transferred to a separatory funnel. Extraction was performed with water (50 mL) and an appropriate amount of ethyl acetate. This was repeated three times. The organic phases were combined and washed with water (50 mL x 2) and brine (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by silica gel column chromatography to obtain compound 7-2 with a yield of 66.7%.

[0084] Preparation of compound I2:

[0085]

[0086] Compound 7-2 (0.2 g, 0.4 mmol) was dissolved in dichloromethane (9 mL), and trifluoroacetic acid (0.9 g, 7.9 mmol) was added dropwise. The mixture was stirred at room temperature for 1 h. The reaction was monitored by TLC until complete. The reaction solution was evaporated to dryness under reduced pressure, and 40% NaOH aqueous solution (50 mL) and an appropriate amount of dichloromethane were added for extraction. This was repeated three times. The organic phases were combined, washed with water (50 mL × 2) and brine (50 mL), and the organic layer was dried over anhydrous sodium sulfate, filtered, and evaporated to dryness under reduced pressure. The crude product was purified by thin-layer chromatography to obtain compound I2 in a yield of 59.4%.

[0087] H NMR spectra of compound I1 and compound I2 ( 1 The characterization information of H NMR and mass spectrometry (M / Z) is shown in Table 1. The characterization data demonstrate the successful synthesis of tetrahydroisoquinoline derivatives Compound I1 and Compound I2.

[0088] Table 1 Characterization information of compound I1 and compound I2

[0089]

[0090]

[0091] Example 3

[0092] The minimum inhibitory concentration (MIC) of compound I1 and compound I2 against different types of strains (Gram-positive sensitive bacteria: Bacillus pumilus CMCC63202, sensitive Staphylococcus aureus S.aureus ATCC25923; Gram-positive resistant bacteria: penicillin-resistant Staphylococcus aureus S.aureus ATCC31007, methicillin-resistant Staphylococcus aureus S.aureusATCC43300; Gram-negative bacteria: Escherichia coli E.coli ATCC25922, Escherichia coli E.coli BW25113, Escherichia coli E.coli BW25113 (ΔAcrB), Acinetobacter baumannii A.baumnnii ATCC19606) was determined, the antibacterial activity of the target compounds was determined, and their antibacterial spectrum was explored.

[0093] The MICs of compounds I1 and I2 were determined using the two-fold broth dilution method specified by the International Association of Antimicrobial Infections. The specific steps were as follows: 190 μL of LB broth was added to column 1 of a 96-well plate, and 100 μL of LB broth was added to columns 2-10. 10 μL of a 10240 μg / mL stock solution of the compound was added to the first column of each row. Mix thoroughly using a multichannel pipette, then pipette 100 μL to the second column and continue mixing. This continued until the tenth column was mixed, after which 100 μL was aspirated and discarded. Columns 11 and 12 each contained 100 μL of LB broth as a positive and negative control. 5 μL of bacterial culture was added to columns 1-11. The plates were incubated in a 37°C incubator for 18-20 h, and the MIC values ​​were read. The antibacterial activities of the target compounds were determined based on this method, as shown in Table 2.

[0094] Table 2 In vitro antibacterial MIC of compound I1 and compound I2, unit μg / mL

[0095]

[0096] Compounds I1 and I2 exhibited excellent and broad-spectrum antibacterial activity against different types of strains, and the MIC values ​​for the above-mentioned test strains were maintained below 0.5 μg / mL. In particular, the MIC value of compound I2 against Bacillus pumilus CMCC63202 was as low as 0.0078 μg / mL, indicating that tetrahydroisoquinoline derivative antibacterial agents are broad-spectrum antibacterial agents.

[0097] n-Phenylnaphthylamine (NPN) is a hydrophobic fluorescent dye. When the outer membrane of Gram-negative bacteria is damaged or ruptured, NPN will pass through the damaged outer membrane from the water-soluble environment outside the bacteria into the hydrophobic environment inside the bacteria, showing a trend of increased fluorescence. Therefore, in the experiment, if the fluorescence signal is monitored to be enhanced after adding the test compound, it means that the compound exhibits outer membrane permeability. Polymyxin B (polymyxin B) is a polypeptide antibiotic and also an outer membrane permeabilizer. It has an inhibitory effect on a variety of Gram-negative bacteria. At the same time, PAβN is also a bacterial inner and outer membrane permeabilizer. Therefore, polymyxin B and PAβN are used as positive controls, and DMSO, the solvent used for the test compound, is used as a negative control. By continuously monitoring the intensity changes of the fluorescence signal, it is determined whether the tetrahydroisoquinoline derivative antibacterial agent with antibacterial activity has an outer membrane permeability mechanism. Compound I2 was set to two concentrations of MIC and 1 / 2MIC to test the effect of the compound on the bacterial outer membrane permeability at a reasonable concentration. As Figure 1 As shown, compound I2 had no effect on outer membrane permeability at its MIC and 1 / 2MIC, indicating that the excellent antibacterial activity of compound I2 does not rely on the outer membrane permeability mechanism.

[0098] 3,3'-dipropylthiocarbocyanine iodide (diSC35) is a fluorescent dye that is sensitive to membrane potential. Under normal circumstances, due to the existence of the potential gradient, the dye diSC35 is absorbed by bacteria and accumulated in the membrane, and self-quenching causes a slight decrease in fluorescence intensity. However, if the compound destroys the inner membrane proton gradient and dissipates the bacterial membrane potential, the dye diSC35 will be displaced into the bacterial in vitro environment, resulting in a significant increase in fluorescence intensity. Therefore, diSC35 can be used to continuously monitor the intensity changes of the fluorescence signal before and after the addition of the test compound to determine whether the compound will destroy the inner membrane proton gradient. Compound I2 was set to two concentrations of MIC and 1 / 2MIC to test the effect of the compound on the inner membrane proton gradient at a reasonable concentration. Figure 2 As shown in the results, compound I2 had no effect on the inner membrane proton gradient at its MIC and 1 / 2MIC, indicating that the excellent antibacterial activity of compound I2 does not rely on the inner and outer membrane permeabilization mechanism.

[0099] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A tetrahydroisoquinoline derivative antibacterial agent, characterized in that: Having the structure shown in Formula I or a pharmaceutically acceptable salt thereof; ； Where R 1 and R 2 are each selected from hydrogen or chlorine and are different, -C 10 H 21 It is a straight chain structure.

2. A method for preparing the tetrahydroisoquinoline derivative antibacterial agent according to claim 1, characterized in that: The following steps are involved: a. Compound 1 was dissolved in toluene, and aminoacetaldehyde dimethyl acetal was added to reflux reaction. After the reaction, sodium borohydride was added to extract and react to obtain compound 2; b. Compound 2 was dissolved in dichloromethane, and triethylamine, p-toluenesulfonyl chloride and 4-dimethylaminopyridine were added to react to obtain compound 3; c. Compound 3 and anhydrous aluminum chloride were dissolved in dichloromethane and reacted under nitrogen to obtain compound 4; d. Compound 4 was dissolved in glacial acetic acid, and sodium cyanoborohydride was added to react to obtain compound 5; e. Compound 5 and cesium carbonate were dissolved in acetonitrile, and bromodecane was added under nitrogen protection and refluxed to obtain compound 6; f, compound 6 and sodium tert-butoxide, N -Boc-piperazine was dissolved in toluene, and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine and bis(dibenzylideneacetone)palladium were added, and the reaction was carried out under nitrogen protection to obtain compound 7; g. Compound 7 was dissolved in dichloromethane, and trifluoroacetic acid was added to react to obtain a tetrahydroisoquinoline derivative antibacterial agent having the structure shown in Formula I; Among them, R 1 , R 2 , -C 10 H 21 As defined in claim 1.

3. The preparation method according to claim 1, wherein In step a, the reaction was refluxed at 119-121°C for 5.9-6.1 hours, and sodium borohydride was added and reacted at room temperature for 0.9-1.1 hours; Alternatively, in step b, the reaction is carried out at room temperature for 0.9 to 1.1 h; Alternatively, in step c, the reaction is carried out at room temperature under nitrogen protection for 11.9 to 12.1 hours, and after the reaction is completed, a saturated sodium bicarbonate solution is added dropwise at 0°C to quench the reaction; Alternatively, in step d, the reaction is carried out at room temperature for 1.9 to 2.1 hours, and after the reaction, the pH is adjusted to acidic to precipitate compound 5; Alternatively, in step e, the reaction is refluxed at 84.9-85.1° C. for 11.9-12.1 h; Alternatively, in step f, the reaction is carried out at 99.9-101.1° C. for 11.9-12.1 h under nitrogen protection; Alternatively, in step g, the reaction is carried out at room temperature for 0.49 to 0.51 h, and the pH is adjusted to alkaline after the reaction.

4. A composition, characterized in that The invention comprises the tetrahydroisoquinoline derivative antibacterial agent as claimed in claim 1.

5. A pharmaceutical preparation, characterized in that The invention comprises the tetrahydroisoquinoline derivative antibacterial agent as claimed in claim 1 and pharmaceutically acceptable excipients.

6. The pharmaceutical preparation according to claim 5, wherein The pharmaceutically acceptable excipients include at least one of a solvent, a disintegrant, a flavoring agent, a preservative, a colorant and a binder.

7. The pharmaceutical preparation according to claim 5, wherein The pharmaceutical preparation can be taken in the form of injection, tablet, pill or capsule.

8. The pharmaceutical preparation according to claim 5, wherein The dosage form of the pharmaceutical preparation is a suspension or an emulsion.

9. Use of the tetrahydroisoquinoline derivative antibacterial agent according to claim 1 and / or the composition according to claim 4 and / or the pharmaceutical preparation according to any one of claims 5 to 8 in the preparation of an antibacterial product.

10. The use according to claim 9, characterized in that The antimicrobial products include antimicrobial drugs.

11. The use according to claim 9, characterized in that The target bacteria of the antimicrobial product include Gram-positive bacteria or Gram-negative bacteria.

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