A pleuromutilin derivative compound and its preparation method and application

Abstract

The present invention discloses a pleuromutilin derivative compound, its preparation method, and application. The method comprises adding pleuromutilin and p-toluenesulfonyl chloride to methyl tert-butyl ether, mixing the mixture, adding sodium hydroxide solution dropwise with stirring, and reacting under reflux to obtain intermediate 1. Intermediate 1 and cysteamine hydrochloride are added to tetrahydrofuran, benzyltributylammonium chloride and sodium hydroxide solution are added dropwise with stirring, and the mixture is reacted with stirring for 4-5 hours to obtain intermediate 2. Intermediate 2, indole acid, and catalyst 2 are added to dichloromethane, and an amidation reaction is carried out at room temperature with stirring for 12-24 hours to obtain the pleuromutilin derivative compound. The pleuromutilin derivative compound of the present invention has a simple preparation process and a high yield. The derivative compound has good in vitro antibacterial activity and is particularly suitable as a new antibacterial drug for preventing and treating infectious diseases caused by bacteria in humans or animals.

Description

Technical Field

[0001] The present invention belongs to the field of medicinal chemistry, and in particular relates to a pleuromutilin derivative compound having 2-aminoethanethiol and an indole side chain, a pharmaceutically acceptable salt thereof, a preparation method of the compound, and applications of the compound. Background Art

[0002] The widespread use and misuse of antimicrobial drugs in veterinary medicine has led to a growing prevalence of drug-resistant bacteria from animals. These bacteria can be transmitted to humans through the food chain, leaving human medicine unavailable. In recent years, the surge in antimicrobial use has led to a growing incidence of drug resistance in animal-derived bacteria. Animal-derived drug-resistant bacteria and their resistance can be transmitted to humans through the food chain and other pathways, posing a significant threat to human health. Drug-resistant bacteria, particularly those such as Staphylococcus aureus and Streptococcus pneumoniae, pose a serious threat to human health. Therefore, the development of new drugs to combat drug-resistant bacteria is crucial.

[0003] Pleuromutilin is a diterpenoid compound with antibacterial activity isolated from the higher fungi pleurotusmutiliz (Fr.) Sacc. and pleurotusPasseckeranius Pilat. It is a tricyclic diterpenoid compound with a 5-6-8 tricyclic ring. Its molecular structure is shown below:

[0004]

[0005] Research has shown that this class of compounds inhibits bacterial protein synthesis at the ribosome level, acting on the 23S RNA of the bacterial 50S ribosome subunit, with the binding site located in the V domain of the peptidyl transferase (PTC). The ternary nucleus binds to the active pocket of the A site, while the side chain partially covers the P site where tRNA binds to the ribosome, achieving antibacterial activity by inhibiting bacterial protein synthesis. Pleuromutilin compounds have a different nucleus structure from common clinical antibacterial drugs, making them less likely to develop cross-resistance with other structurally similar antibacterial agents.

[0006] Pleuromutilin C 14 The ester structure side chain is the main site for chemical modification. 14 Most of the studies on the structural modification of the side chain are based on the premise of retaining the ester structure. 22 The structure-activity relationship shows that C 14 If the side chain is connected to a thioether side chain with a basic center, the activity of the derivative will be decisively improved. Summary of the Invention

[0007] In order to address the deficiencies of the prior art, the primary object of the present invention is to provide a pleuromutilin derivative compound having 2-aminoethanethiol and indole side chains or a pharmaceutically acceptable salt thereof.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned pleuromutilin derivative compound.

[0009] Another object of the present invention is to provide applications of the above-mentioned pleuromutilin derivative compounds.

[0010] The present invention is achieved by providing a pleuromutilin derivative compound having 2-aminoethanethiol and indole side chains, characterized in that the compound has a structural formula as shown in the following formula (I):

[0011]

[0012] Among them, R1 is a hydrogen group or a methoxy group, R2 is a hydrogen group or a fluoro group, and R3 is a hydrogen group or a methyl group.

[0013] The present invention further discloses a pharmaceutically acceptable salt of the above-mentioned pleuromutilin derivative compound, which is a salt formed by the pleuromutilin derivative compound and hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, fumaric acid, maleic acid, oxalic acid, malonic acid, glutamic acid, aspartic acid, succinic acid, citric acid or malic acid.

[0014] Preferably, the chemical structural formula of the pharmaceutically acceptable salt of the pleuromutilin derivative compound is:

[0015]

[0016] The present invention further discloses a method for preparing the above-mentioned pleuromutilin derivative compound, which comprises the following steps:

[0017] (1) Pleuromutilin and p-toluenesulfonyl chloride were added to methyl tert-butyl ether and mixed, and a 10 mol / L sodium hydroxide solution was added dropwise with stirring. The mixture was refluxed at 55-60°C for 1-2 hours. The reaction product was cooled, washed, and dried to obtain an intermediate 1 having a structure shown in formula (II);

[0018]

[0019] (2) Intermediate 1 and cysteamine hydrochloride are added to tetrahydrofuran, and catalyst 1 benzyltributylammonium chloride and 20 wt% sodium hydroxide solution are added dropwise with stirring at 35-36°C, and the mixture is stirred at 50-55°C for 4-5 hours. The reaction product is concentrated, extracted, dried, and purified to obtain intermediate 2 having the structure shown in the following formula (III);

[0020]

[0021] (3) adding intermediate 2, indole acid and catalyst 2 to dichloromethane, and carrying out an amidation reaction at room temperature with stirring for 12 to 24 hours. After the reaction is quenched, the reaction product is extracted, dried and purified to obtain a pleuromutilin derivative compound; wherein the indole acid is selected from any one of 3-indolecarboxylic acid, 1-methylindole-3-carboxylic acid, 6-fluoro-indole-3-carboxylic acid and 5-methoxyindole-3-carboxylic acid; and the catalyst 2 is a mixture of DCC and DMAP.

[0022] Preferably, in step (1), the molar volume ratio of pleuromutilin, p-toluenesulfonyl chloride, methyl tert-butyl ether, and sodium hydroxide solution is 10-15 mmol: 13-17 mmol: 12-15 mL: 2.0-2.5 mL;

[0023] The reaction product is subjected to cooling, washing and drying as follows: the reaction product is cooled to 0° C., filtered, the obtained white solid is washed three times with methyl tert-butyl ether, then washed three times with deionized water, and dried in vacuo at 45° C.

[0024] Preferably, in step (2), the molar volume ratio of the intermediate 1, cysteamine hydrochloride, tetrahydrofuran, benzyltributylammonium chloride, and sodium hydroxide solution is 7.1-20.8 mmol: 14.2-41.6 mmol: 28-80 mL: 0.7-2.1 mmol: 5-15 mL;

[0025] The concentration, extraction, drying and purification of the reaction product specifically include: concentrating the reaction solution, extracting with dichloromethane, drying with anhydrous sodium sulfate, and purifying by column chromatography with ethyl acetate / 1% diethylamine.

[0026] Preferably, in step (3), the molar volume ratio of the intermediate 2, various indolecarboxylic acids, catalyst 2, and dichloromethane is 1.1-1.3 mmol: 1.3-1.6 mmol: 1.8-2.3 mmol: 10-20 mL;

[0027] The molar ratio of DCC to DMAP in the catalyst 2 is 1.3-1.6 mmol: 0.5-0.7 mmol;

[0028] The quenching is performed by using a saturated sodium bicarbonate solution, the extraction is performed by using dichloromethane, the drying is performed by using anhydrous sodium sulfate, and the purification is performed by using column chromatography.

[0029] The present invention further discloses the use of the pleuromutilin derivative compound or the pharmaceutically acceptable salt of the pleuromutilin derivative compound in the preparation of antibacterial drugs for treating infectious diseases.

[0030] The present invention further discloses an antibacterial drug, which comprises the pleuromutilin derivative compound and / or one or more pleuromutilin derivative compounds in a pharmaceutically acceptable carrier, excipient or diluent.

[0031] The present invention further discloses another antibacterial drug, which comprises the pharmaceutically acceptable salt and / or the salt in a pharmaceutically acceptable carrier, excipient or diluent.

[0032] The present invention overcomes the deficiencies of the prior art and provides a pleuromutilin derivative compound and its preparation method and application. The synthetic route of the pleuromutilin derivative compound of the present invention is shown in the following formula:

[0033]

[0034] Among them, R1 is a hydrogen group or a methoxy group, R2 is a hydrogen group or a fluoro group, and R3 is a hydrogen group or a methyl group.

[0035] Compared with the shortcomings and deficiencies of the prior art, the present invention has the following beneficial effects:

[0036] (1) The present invention obtains pleuromutilin derivative compounds having 2-aminoethanethiol and indole structures through substitution and amidation reactions. These compounds are extensively screened for antibacterial activity, and it is found for the first time that such derivative compounds have good in vitro antibacterial activity and are particularly suitable as new antibacterial drugs for preventing and treating infectious diseases caused by bacteria in humans or animals. In particular, the antibacterial activity against Gram-positive bacteria, such as Staphylococcus aureus and Streptococcus, is superior to that of the marketed tylosin, and also has good antibacterial activity against drug-resistant bacteria (MRSA, MRSE);

[0037] (2) The preparation process of the pleuromutilin derivative compound of the present invention is simple and has a high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the nuclear magnetic spectrum of the pleuromutilin derivative compound 1 in the embodiment of the present invention;

[0039] Figure 2 is the nuclear magnetic spectrum of the pleuromutilin derivative compound 2 in the embodiment of the present invention;

[0040] Figure 3 is the nuclear magnetic spectrum of the pleuromutilin derivative compound 3 in the embodiment of the present invention;

[0041] Figure 4 It is the nuclear magnetic spectrum of the pleuromutilin derivative compound 4 in the embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] Example 1

[0044] (1) Preparation of Intermediate 1

[0045] 5.0 g (13.2 mmol) of pleuromutilin and 2.8 g (14.5 mmol) of p-toluenesulfonyl chloride were added to 13.2 mL of methyl tert-butyl ether, and 2.2 mL of 10 mol / L sodium hydroxide solution was added dropwise with stirring. After the addition was complete, the mixture was heated to 55° C. and refluxed for 1 h, resulting in the formation of a large amount of white precipitate. After the reaction was completed, the mixture was cooled to 0° C. The filtered white solid was rinsed three times with methyl tert-butyl ether and then three times with deionized water. The white solid was vacuum dried at 45° C. to obtain intermediate 1 having the structure represented by formula (II) in a yield of 92.9%.

[0046] It can be used directly in the next step without purification.

[0047]

[0048] (2) Preparation of Intermediate 2

[0049] 3.9 g (7.1 mmol) of intermediate 1 obtained in Example 1 and 1.6 g (14.2 mmol) of cysteamine hydrochloride were added to 28 mL of tetrahydrofuran, and then 0.22 g (0.7 mmol) of catalyst benzyltributylammonium chloride and 5 mL of 20 wt% sodium hydroxide solution were added with stirring at 35°C. After the addition was complete, the temperature was raised to 50°C and stirred for 4 h. After concentration, the mixture was extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by column chromatography (ethyl acetate / 1% diethylamine) to obtain intermediate 2 having the structure shown in formula (III) in a yield of 95.0%.

[0050] 1H NMR (400MHz, CDCl3) δ6.48 (dd, J=17.4, 11.0Hz, 1H), 5.75 (d, J=8.5Hz, 1H), 5.35 (d, J=10. 9Hz,1H),5.21(d,J=17.4Hz,1H),3.36(d,J=6.5Hz,1H),3.14(s,2H),2.88(t,J=6.2Hz,2H ),2.70(t,J=6.3Hz,2H),2.41–2.05(m,5H),1.77(d,J=14.7Hz,1H),1.65(q,J=11.5Hz,3) ,1.47(d,J=14.8Hz,9H),1.22–1.09(m,4H),0.88(d,J=6.9Hz,3H),0.74(d,J=6.9Hz,3H). 13 C NMR (101MHz, CDCl3) δ217.30,169.24,139.38,117.49,74.92,69.60,58.50,45.75,45.13,44.22,42.06 ,40.96,37.14,37.07,36.31,34.76,34.33,30.73,27.15,26.64,25.14,17.13,15.20,11.80.Chemical Formula:C 24 H 39 NO4S,Exact Mass:437.2600,HRMS(+TOF MS):438.2656(M+H + ).

[0051]

[0052] (3) Preparation of Compound 1

[0053] 0.51 g (1.17 mmol) of the intermediate (III) obtained in Example 2 was dissolved in 10 mL of dichloromethane, and 1.41 mmol of 3-indolecarboxylic acid and 2.11 mmol of catalyst 2 (0.29 g (1.49 mmol) of N,N'-dicyclohexylcarboximide (DCC) and 0.07 g (0.62 mmol) of 4-dimethylaminopyridine (DMAP)) were added. After the addition was completed, the mixture was stirred at room temperature for 12 to 24 h, quenched with saturated sodium bicarbonate solution, extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by column chromatography (petroleum ether:ethyl acetate = 1:1 → petroleum ether:ethyl acetate = 1:2). After concentration, the target compound 1 was obtained with a yield of 70.4%.

[0054] The structural formula of compound 1 is:

[0055]

[0056] The compound 1 was characterized and its NMR spectrum was as shown in Figure 1 As shown, the characterization data is as follows:

[0057] 1 H NMR(400MHz,Chloroform-d)δ9.85(s,1H),8.07–8.00(m,1H),7.74(d,J=2.9Hz,1H),7.46–7.37(m,1H),7.24–7.17(m,2H),6.80(t,J=5.8Hz,1H), 6.42(dd,J=17.4,11.0Hz,1H),5.72(d,J=8.4Hz,1H),5.23(dd,J=11.0,1.6Hz,1H),5.13(dd,J=17.4,1.6Hz,1H),3.79–3.57(m,2H),3.33(t,J=7. 9Hz, 1H), 3.20 (s, 2H), 2.86 (t, J = 6.2Hz, 2H), 2.34–2.26 (m, 1H), 2.24–2. 10(m,3H),2.08–2.03(m,2H),1.73(dq,J=14.5,3.2Hz,1H),1.68–1.56(m ,3H),1.55–1.46(m,1H),1.42(s,3H),1.39–1.28(m,2H),1.12(s,3H),1. 06(dd,J=14.0,4.4Hz,1H), 0.86(d,J=6.9Hz,3H), 0.70(d,J=7.1Hz,3H). 13 C NMR (101MHz, CDCl3) δ217.42,169.54,165.97,139.20,136.77,128.84,124.85,122.97,121.75,120.13,117.46,112.41,112.02,74.82,69. 93,58.39,45.66,45.10,44.14,41.98,38.12,36.95,36.22,34.68,34.47,33.49,30.61,27.03,26.63,25.05,17.07,15.12,11.79.Chemical Formula:C 33 H 44 N2O5S,Exact Mass:580.2971,HRMS(+TOF MS):581.3020(M+H + ).

[0058] Example 2

[0059] The preparation process of Example 2 is basically the same as that of Example 1, except that in step (3), indole acid is 1-methylindole-3-carboxylic acid, and the target compound 2 is finally obtained with a yield of 76.6%.

[0060] The structural formula of compound 2 is:

[0061]

[0062] The compound 2 was characterized and its NMR spectrum was as shown in Figure 2 As shown, the characterization data is as follows:

[0063] 1 H NMR (400MHz, CDCl3) δ8.09–8.01(m,1H),7.72–7.66(m,1H),7.39–7.31(m,1H),7.34–7.23(m,1H),6.70(t,J=6.1Hz,1H),6.51–6.39( m,1H),5.75(dd,J=8.4,2.1Hz,1H),5.32–5.24(m,1H),5.17(dq,J=17.4,1.6Hz,1H),3.83–3.77(m,3H),3.80–3.59(m,2H),3.36(t,J =8.3Hz,1H),3.23(s,2H),2.88(t,J=5.1Hz,2H),2.37–2.28(m,1H),2.28–2.15(m,2H),2.14–2.05(m,2H),1.76(d,J=14.4Hz,1H),1. 71–1.51(m,4H),1.48–1.42(m,3H),1.42–1.28(m,2H),1.15(s,3H),1.13–1.05(m,1H),0.88(d,J=6.4Hz,3H),0.73(d,J=6.7Hz,3H). 13 C NMR (101MHz, CDCl3) δ217.21,169.48,165.29,139.22,137.43,132.64,125.57,122.72,121.67,120.54,117.43,110.90,110.21,74.78,69.87, 58.37,45.65,45.10,44.15,41.98,37.95,36.94,36.24,34.65,34.43,3 3.56,33.48,30.62,27.04,26.64,25.05,17.05,15.10,11.76.Chemical Formula:C34 H 46 N2O5S,Exact Mass:594.3127,HRMS(+TOF MS):595.3171(M+H + ).

[0064] Example 3

[0065] The preparation process of Example 3 is basically the same as that of Example 1, except that in step (3), indole acid is 6-fluoro-indole-3-carboxylic acid, and the target compound 3 is finally obtained with a yield of 80.4%.

[0066] The structural formula of compound 3 is:

[0067]

[0068] The compound 3 was characterized and its NMR spectrum was as shown in Figure 3 As shown, the characterization data is as follows:

[0069] 1 H NMR (400MHz, CDCl3) δ9.86(s,1H),7.99(dd,J=8.9,5.2Hz,1H),7.65(d,J=2.3Hz,1H),7.05(dd,J=9.2,2.3Hz,1H),6.97(td,J=9.1,2.3Hz,1H),6.78( t,J=5.9Hz,1H),6.41(dd,J=17.4,11.1Hz,1H),5.72(d,J=8.4Hz,1H),5.22 (dd,J=11.0,1.5Hz,1H),5.14(dd,J=17.4,1.5Hz,1H),3.78–3.68(m,1H),3 .66–3.51(m,2H),3.35(t,J=7.0Hz,1H),3.21(s,2H),2.86(t,J=6.1Hz,2H) ,2.35–2.27(m,1H),2.26–2.16(m,2H),2.13–2.05(m,2H),1.78–1.71(m,1H ),1.67–1.56(m,3H),1.54–1.46(m,1H),1.43(s,3H),1.36–1.28(m,2H),1. 12(s,3H),1.09–1.02(m,1H),0.86(d,J=6.9Hz,3H),0.70(d,J=6.9Hz,3H). 13CNMR(101MHz, CDCl3)δ217.38,169.70,165.65,159.01,139.21,136.84,128.55,121.73,121.37,117.47,112.20,110.33,98.68,74.85 ,70.05,58.41,45.69,45.13,44.18,42.01,38.15,36.96,36.25,34.70,34.56,33.55,30.63,27.06,26.63,25.08,17.09,15.12,11.78.

[0070] Chemical Formula:C 33 H 43 FN2O5S,Exact Mass:598.2877,HRMS(+TOF MS):599.3231(M+H + ).

[0071] Example 4

[0072] The preparation process of Example 4 is basically the same as that of Example 1, except that in step (3), the indole acid is 5-methoxyindole-3-carboxylic acid, and the target compound 4 is finally obtained with a yield of 84.7%.

[0073] The structural formula of compound 4 is:

[0074]

[0075] The compound 4 was characterized and its NMR spectrum was as shown in Figure 4 As shown, the characterization data is as follows:

[0076] 11H NMR (400 MHz, CDCl3) δ 9.54 (d, J = 3.0 Hz, 1H), 7.67 (d, J = 2.9 Hz, 1H), 7.59 (d, J = 2.4 Hz, 1H), 7.27 (d, J = 7.6 Hz, 1H), 6.86 (dd, J = 8.9, 2.4 Hz, 1H), 6.76 (t, J = 5.8 Hz, 1H), 6.41 (dd, J = 17.4, 11.0 Hz, 1H), 5.72 (d, J = 8.4 Hz, 1H), 5.21 (dd, J = 11.0, 1.5 Hz, 1H), 5.12 (dd, J = 17.4, 1.6 Hz, 1H), 3.84 (s, 3H), 3.79–3.70 (m, 1H), 3.63–3.54 (m, 1H), 3.33 (dd, J = 9.9, 6.4 Hz, 1H), 3.20 (s, 2H), 2.86 (t, J = 6.1 Hz, 2H), 2.34–2.26 (m, 1H), 2.24–2.11 (m, 2H), 2.10–2.05 (m, 2H), 1.73 (dq, J = 14.6, 3.1 Hz, 1H), 1.68–1.54 (m, 3H), 1.54–1.44 (m, 1H), 1.42 (s, 3H), 1.37–1.26 (m, 2H), 1.11 (s, 3H), 1.07 (dd, J = 14.1, 4.3 Hz, 1H), 0.85 (d, J = 6.9 Hz, 3H), 0.69 (d, J = 7.0 Hz, 3H). 13 13C NMR (101 MHz, CDCl3) δ 217.37, 169.62, 165.98, 155.69, 139.15, 131.64, 128.36, 125.87, 117.50, 113.53, 112.95, 111.79, 102.15, 74.83, 69.99, 58.39, 56.05, 45.66, 45.16, 44.15, 41.99, 37.94, 36.94, 36.22, 34.68, 34.55, 33.69, 30.62, 27.05, 26.59, 25.06, 17.07, 15.11, 11.79. Chemical Formula: C 34 H 46 N2O6S, Exact Mass: 610.3077, HRMS(+TOF MS): 611.3125 (M + H + ).

[0077] Example 5

[0078] This Example 5 is basically the same as Example 1, except that in step (1), 10 mmol of pleuromutilin and 13 mmol of p-toluenesulfonyl chloride are added to 12 mL of methyl tert-butyl ether, and 2 mL of 10 mol / L sodium hydroxide solution is added dropwise with stirring. After the addition is complete, the mixture is heated to 60° C. and refluxed for 1 hour, resulting in the formation of a large amount of white precipitate. After the reaction is completed, the mixture is cooled to 0° C., and the filtered white solid is rinsed three times with methyl tert-butyl ether and then three times with deionized water. The white solid is vacuum-dried at 45° C. to obtain Intermediate 1 having a structure represented by Formula (II) in a yield of 91.0%.

[0079] Example 6

[0080] This Example 6 is basically the same as Example 1, except that in step (1), 15 mmol of pleuromutilin and 17 mmol of p-toluenesulfonyl chloride are added to 15 mL of methyl tert-butyl ether, and 2.5 mL of 10 mol / L sodium hydroxide solution is added dropwise with stirring. After the addition is complete, the mixture is heated to 55° C. and refluxed for 1 hour, resulting in the formation of a large amount of white precipitate. After the reaction is completed, the mixture is cooled to 0° C., and the filtered white solid is rinsed three times with methyl tert-butyl ether and then three times with deionized water. The white solid is vacuum-dried at 45° C. to obtain Intermediate 1 having a structure represented by Formula (II) in a yield of 90.5%.

[0081] Example 7

[0082] This Example 7 is basically the same as Example 1, except that, in step (2), 20.8 mmol of the intermediate 1 prepared in Example 1 and 41.6 mmol of cysteamine hydrochloride are added to 80 mL of tetrahydrofuran, and then 2.1 mmol of the catalyst benzyltributylammonium chloride and 15 mL of a 20 wt% sodium hydroxide solution are added at 36° C. with stirring. After the addition is complete, the temperature is raised to 55° C. and stirred for 5 h. After concentration, the mixture is extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by column chromatography (ethyl acetate / 1% diethylamine) to obtain the intermediate 2 having the structure shown in formula (III) with a yield of 94.2%.

[0083] Example 8

[0084] This Example 8 is basically the same as Example 1, except that in step (3), 1.3 mmol of the intermediate (III) prepared in Example 2 was dissolved in 20 mL of dichloromethane, and 2.3 mmol of catalyst 2 (1.6 mmol of 3-indolecarboxylic acid, 1.3 mmol of N,N'-dicyclohexylcarboximide (DCC), and 0.7 mmol of 4-dimethylaminopyridine (DMAP)) was added. After the addition was completed, the mixture was stirred at room temperature for 12 h, quenched with saturated sodium bicarbonate solution, extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by column chromatography (petroleum ether:ethyl acetate = 1:1 → petroleum ether:ethyl acetate = 1:2). After concentration, the target compound 1 was obtained with a yield of 70.2%.

[0085] Example 9

[0086] This Example 9 is basically the same as Example 1, except that in step (3), 1.1 mmol of the intermediate (III) obtained in Example 2 was dissolved in 10 mL of dichloromethane, and 1.8 mmol of catalyst 2 (1.3 mmol of 3-indolecarboxylic acid, 1.3 mmol of N,N'-dicyclohexylcarboximide (DCC), and 0.5 mmol of 4-dimethylaminopyridine (DMAP)) was added. After the addition was completed, the mixture was stirred at room temperature for 24 h, quenched with saturated sodium bicarbonate solution, extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by column chromatography (petroleum ether:ethyl acetate = 1:1 → petroleum ether:ethyl acetate = 1:2). After concentration, the target compound 1 was obtained in a yield of 69.3%.

[0087] Application Example Antibacterial Test

[0088] The pleuromutilin derivative compounds 1 to 4 prepared in the above Examples 1 to 4 were all tested for their effects on methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, Staphylococcus aureus (S. aureus-1, S. aureus-29213 and S. aureus-25923), Escherichia coli, Streptococcus agalactiae and Streptococcus dysgalactiae by a two-fold dilution method. equisimilis)(S.dysgalactiae-1, S.dysgalactiae-2, S.dysgalactiae-3), the results are shown in Table 1 and Table 2 (wherein, among the above-mentioned bacteria, the standard strains were purchased from ATCC, and the clinical strains were preserved at the Lanzhou Institute of Animal Husbandry and Veterinary Drugs, Chinese Academy of Agricultural Sciences).

[0089] Table 1 Minimum inhibitory concentration of pleuromutilin derivatives in vitro

[0090]

[0091] Table 2 Minimum inhibitory concentration of pleuromutilin derivatives in vitro

[0092]

[0093] As can be seen from Tables 1 and 2, the inhibitory effects of this type of pleuromutilin derivatives on MRSA, MRSE, S.aureus-1, S.aureus-29213, S.aureus-25923, S.agalactiae-1, S.dysgalactiae-1, S.dysgalactiae-2 and S.dysgalactiae-3 are better than those of the control drug tiamulin, among which compound 1 has the best effect, with an MIC value of 16 times that of tiamulin.

[0094] 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 scope of protection of the present invention.

Claims

1. A pleuromutilin derivative compound having 2-aminoethanethiol and indole side chains, characterized in that: The structural formula of the compound is shown in the following formula (I): Among them, R1 is a hydrogen atom or a methoxy group, R2 is a hydrogen atom or a fluorine atom, and R3 is a hydrogen atom or a methyl group.

2. A pharmaceutically acceptable salt of the pleuromutilin derivative compound according to claim 1, characterized in that: The pharmaceutically acceptable salt is a salt formed by the pleuromutilin derivative compound and hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, fumaric acid, maleic acid, oxalic acid, malonic acid, glutamic acid, aspartic acid, succinic acid, citric acid or malic acid.

3. The pharmaceutically acceptable salt according to claim 2, wherein The chemical structural formula of the pharmaceutically acceptable salt of the pleuromutilin derivative compound is:

4. The method for preparing the pleuromutilin derivative compound according to claim 1, characterized in that: The method comprises the following steps: (1) Pleuromutilin and p-toluenesulfonyl chloride were added to methyl tert-butyl ether and mixed, and a 10 mol / L sodium hydroxide solution was added dropwise with stirring. The mixture was refluxed at 55-60°C for 1-2 hours. The reaction product was cooled, washed, and dried to obtain an intermediate 1 having a structure shown in formula (II); (2) Intermediate 1 and cysteamine hydrochloride are added to tetrahydrofuran, and catalyst 1 benzyltributylammonium chloride and 20 wt% sodium hydroxide solution are added dropwise with stirring at 35-36°C, and the mixture is stirred at 50-55°C for 4-5 hours. The reaction product is concentrated, extracted, dried, and purified to obtain intermediate 2 having the structure shown in the following formula (III); (3) adding intermediate 2, indole acid and catalyst 2 to dichloromethane, and carrying out an amidation reaction at room temperature with stirring for 12 to 24 hours. After the reaction is quenched, the reaction product is extracted, dried and purified to obtain a pleuromutilin derivative compound; wherein the indole acid is selected from any one of 3-indolecarboxylic acid, 1-methylindole-3-carboxylic acid, 6-fluoro-indole-3-carboxylic acid and 5-methoxyindole-3-carboxylic acid; and the catalyst 2 is a mixture of DCC and DMAP.

5. The preparation method according to claim 4, wherein In step (1), the molar volume ratio of pleuromutilin, p-toluenesulfonyl chloride, methyl tert-butyl ether, and sodium hydroxide solution is 10-15 mmol: 13-17 mmol: 12-15 mL: 2.0-2.5 mL; The reaction product is subjected to cooling, washing and drying as follows: the reaction product is cooled to 0° C., filtered, the obtained white solid is washed three times with methyl tert-butyl ether, then washed three times with deionized water, and dried in vacuo at 45° C.

6. The preparation method according to claim 4, wherein In step (2), the molar volume ratio of the intermediate 1, cysteamine hydrochloride, tetrahydrofuran, benzyltributylammonium chloride, and sodium hydroxide solution is 7.1-20.8 mmol: 14.2-41.6 mmol: 28-80 mL: 0.7-2.1 mmol: 5-15 mL; The concentration, extraction, drying and purification of the reaction product specifically include: concentrating the reaction solution, extracting with dichloromethane, drying with anhydrous sodium sulfate, and purifying by column chromatography with ethyl acetate / 1% diethylamine.

7. The preparation method according to claim 4, wherein In step (3), the molar volume ratio of the intermediate 2, various indolecarboxylic acids, catalyst 2, and dichloromethane is 1.1-1.3 mmol: 1.3-1.6 mmol: 1.8-2.3 mmol: 10-20 mL; The molar ratio of DCC to DMAP in the catalyst 2 is 1.3-1.6 mmol: 0.5-0.7 mmol; The quenching is performed by using a saturated sodium bicarbonate solution, the extraction is performed by using dichloromethane, the drying is performed by using anhydrous sodium sulfate, and the purification is performed by using column chromatography.

8. Use of the pleuromutilin derivative compound according to claim 1, or a pharmaceutically acceptable salt of the pleuromutilin derivative compound according to claim 2 or claim 3, in the preparation of an antibacterial drug for treating infectious diseases caused by methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae.

9. An antibacterial drug, characterized in that The drug comprises the pleuromutilin derivative compound according to claim 1 and one or more pharmaceutically acceptable carriers of the pleuromutilin derivative compound.

10. An antibacterial drug, characterized in that: The drug comprises the pharmaceutically acceptable salt according to claim 2 or 3 and a pharmaceutically acceptable carrier of the salt.

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