RU2721833C1 - Method of producing trifluoroacetates of substituted 6-aminoindoles, having antimicrobial action - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to a method of producing trifluoroacetates of substituted 6-aminoindoles, in which corresponding substituted 6-aminoindole in a benzene heated to boiling is reacted with trifluoroacetic acid.EFFECT: obtained compounds, such as 2,3,5-trimethyl-1H-indole-6-ammonium trifluoroacetate, 1,2,3,5-tetramethyl-1H-indole-6-ammonium trifluoroacetate, 2,3-dimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate, 1,2,3-trimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate, can be used as water-soluble synthetic antimicrobial preparations.1 cl, 4 ex

Description

The invention relates to the chemistry of salts of trifluoroacetic acid and aminoindoles, namely, 2,3,5-trimethyl-1H-indole-6-ammonium trifluoroacetate, 1,2,3,5-tetramethyl-1H-indole-6-ammonium trifluoroacetate, trifluoroacetate 2,3-dimethyl-5-methoxy-1H-indole-6-ammonium, trifluoroacetate 1,2,3-trimethyl-5-methoxy-1H-indole-6-ammonium, which can be used in medical practice as means, possessing antimicrobial action.

Throughout the history of the existence of pathogenic microorganisms, the struggle against many of their representatives already studied and newly studied continued. The discovery of antimicrobial agents led to the successful treatment and elimination of some bacterial infections, but revealed strains that are resistant to antimicrobials due to the numerous mechanisms of antibiotic resistance [1-3]. The problem of antibiotic resistance becomes more acute in the 21st century, a study of the mechanisms of acquiring resistance to antimicrobial agents underlies the development of new ways to combat this phenomenon [4-5]. Drug resistance is a growing global threat to public health that affects all major pathogens and antimicrobials [6-7].

When conducting microbiological monitoring in recent years, there has been a tendency to increase the proportion of multiresistant strains, for example, methicillin-resistant S.aureus have a significantly higher frequency of resistance compared to methicillin-sensitive strains, to gentamicin, clindamycin, rifampicin, tetracycline, chloramphenicol, ceftrofolin, ciprofrofolin, ciprofrofolin, ciprofrofolin, ciprofrofolin, ciprofrofolin, ciprofrofolin and erythromycin, P. aeruginosa is insensitive to antiseptic cephalosporins - cefepime and ceftazidime, as well as piperacillin-tazobactam, imipenem, meropenem, representatives of the Enterobacteriaceae family, are resistant to three and more traditionally used antibiotics such as cef. [8-10]

Search and development of new antimicrobial agents is one of the fundamental principles of overcoming the resistance of microorganisms to antibiotics. The need to search for new highly effective and safe antimicrobial compounds is enshrined in the Russian Federation at the legislative level [11].

Substituted aminoindoles with an amino group in the benzene ring are known as starting compounds for the production of trifluoromethyl-substituted indolylamides. Many of the resulting products show various kinds of biological activity. So, in amides, based on 4,7-aminoindoles and trifluoroacetoacetate, based on 7-aminoindoles and ethyl trifluoroacetic acid, a rather high antimicrobial activity was found [12-13]. In this regard, it was interesting to obtain water-soluble aminoindole derivatives containing a trifluoromethyl group in the molecule from 6-amino-2,3,5-trimethyl-, 6-amino-1,2,3,5-tetramethyl-, 6- amino-2,3-dimethyl-5-methoxy-, 6-amino-5-methoxy-1,2,3-trimethylindoles and trifluoroacetic acid and their laboratory study of antimicrobial activity.

The closest technical solution to the claimed invention is a method for producing trifluoromethyl-containing derivatives of aminoindoles by acylation of 2,3-dimethyl- and 1,2,3-trimethyl-7-aminoindoles with ethyl trifluoroacetic acid [13].

The disadvantage of this method is that the resulting indolylamides are not soluble in water, which is a disadvantage when using antimicrobial drugs.

The inventive compounds, their antimicrobial properties and method of obtaining from the prior art are unknown.

The technical result consists in obtaining new water-soluble trifluoromethyl-containing compounds in the molecule of the indole series having effective antimicrobial activity.

The specified technical result is achieved due to the use of a more accessible compound, trifluoroacetic acid, as a trifluoromethyl-containing agent in the reaction, which also allows to obtain target compounds of trifluoroacetates of substituted 6-aminoindoles with higher yield.

The essence of the invention lies in the fact that in the method for producing trifluoroacetates of substituted 6-aminoindoles having antimicrobial activity, the general formula (1):

, (1)

, (1)

where R = H, CH ₃ , R ₁ = CH ₃ , OCH ₃ in order to obtain water-soluble trifluoromethyl substituted aminoindole derivatives, the compounds of general formula (2):

, (2)

, (2)

where R and R ₁ have the indicated meanings, in benzene heated to boiling, they are reacted with trifluoroacetic acid of the general formula (3):

(3)

(3)

The resulting compounds are trifluoroacetates 2,3,5-trimethyl-1H-indole-6-ammonium, 1,2,3,5-tetramethyl-1H-indole-6-ammonium, 2,3-dimethyl-5-methoxy-1H-indole -6-ammonium, 1,2,3-trimethyl-5-methoxy-1H-indole-6-ammonium can be used as water-soluble synthetic antimicrobial agents.

Information confirming the achievement of the technical result is presented in the following examples.

Example 1. Trifluoroacetate 2,3,5-trimethyl-1H-indole-6-ammonium (X-1)

To a solution of 0.1 g (0.57 mmol) of 2,3,5-trimethyl-6-aminoindole in 50 ml of benzene heated to boiling, 0.078 g (0.68 mmol) of trifluoroacetic acid in 10 ml of benzene are added and heated to boiling. The precipitate formed upon cooling is filtered off, washed with benzene, followed by hot hexane. The yield of 2,3,5-trimethyl-1H-indole-6-ammonium trifluoroacetate is 84%. T decom _. . > 190 ° C, R _f = 0.20. Found,%: C 53.99; H, 5.06. C ₁₃ H ₁₅ N ₂ F ₃ O ₂ . Calculated,%: C 54.16; H, 5.24. UV spectrum (ethanol) λ _max (log ε): 207 _pl (4.26), 233 (4.52), 395 (3.76); ¹ H NMR spectrum (DMSO-d ₆ ): 2.13 (3H, s, 3-CH ₃ ), 2.29 (3H, s, 2-CH ₃ ), 2.36 (3H, s, 5-CH _3), 7.26 (1H, s, H-4), 7.30 (1H, s, H-7), 9.69 (3H, _{br s,} 6-NH _3), 10.81 (H s, H-1) ppm, ¹⁹ F NMR spectrum (DMSO-d ₆ ): -73.58 ppm Mass spectrum Jm / z (% to J _max ): 174 (100.00), 173 (86.00), 159 (30.00), 69 (53.00), 45 (73.00).

Example 2. 1,2,3,5-tetramethyl-1H-indole-6-ammonium trifluoroacetate (C-1)

Obtained similarly from 0.10 g (5.3 mmol) of 6-amino-1,2,3,5-tetramethylindole and 0.68 g (6.0 mmol) of trifluoroacetic acid. The yield of 1,2,3,5-tetramethyl-1H-indole-6-ammonium trifluoroacetate is 80.5%, T decomp. > 173 ° C, R _f = 0.38. Found,%: C 55.50; H 5.59. C ₁₄ H ₁₇ N ₂ F ₃ O ₂ . Calculated,%: C 55.63; H, 5.67. UV spectrum (ethanol) λ _max (log ε)): 210 _pl (4.28), 235 (4.53), 300 (3.83), ¹ H NMR spectrum (DMSO-d ₆ ): 2.16 ( 3H, s, 3-CH ₃ ), 2.31 (3H, s, 2-CH ₃ ), 2.38 (3H, s, 5-CH ₃ ), 3.59 (3H, s, 1-CH ₃ ), 7.31 (1H, s, H-4), 7.33 (1H, s, H-7), 9.69 (3H, s _br, 6 H, _3-N), NMR ¹⁹ F (DMSO -d ₆ ): -73.66 ppm. Mass spectrum Jm / z (% to J _max ): 188 (100.00), 187 (71.00), 173 (39.00), 69 (43.00), 45 (78.00), 28 ( 61.00), 17 (12.00)

Example 3. 2,3-Dimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate (X-2)

Obtained similarly from 0.15 g (0.79 mmol) of 6-amino-2,3-dimethyl-5-methoxyindole and 0.097 g (0.85 mmol) of trifluoroacetic acid. The yield of 2,3-dimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate is 54%. T decom. > 161 ºС. R_f= 0.24. Found,%: C 53.99; H, 5.06. WITH_thirteenN_fifteenN₂F₃O₃. Calculated,%: C 54.16; H, 5.24. UV spectrum (ethanol) λ_max(log ε): 207_pl(4.42), 230 (4.55), 303 (4.03); NMR spectrum¹N (DMSO-d₆): 2.15 (3H, s, 3-CH₃), 2.29 (3H, s, 2-CH₃), 3.90 (3H, s, 5-OCH)₃), 7.08 (1H, s, H-4), 7.26 (1H, s, H-7), 9.56 (3H, s_{the ear}6-NH₃), 10.75 (H, s, H-1) ppm, NMR spectrum^nineteenF (DMSO-d₆): -73.56 ppm Mass spectrum Jm / z (% to J_max): 191 (18.32), 190 (100.00), 176 (12.01), 175 (95.90), 147 (69.47), 145 (13.71), 69 (20.72) 45 (24.22), 28 (10.81).

Example 4. 1,2,3-trimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate (C-2)

Obtained similarly from 0.14 g (6.8 mmol) of 6-amino-5-methoxy-1,2,3-trimethylindole and 0.08 g (7.0 mmol) of trifluoroacetic acid. Yield of 1,2,3-trimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate 71.1%, T decomp. > 160 ºС. R_f= 0.46. Found,%: C 52.69; H, 5.21. WITH_thirteenN_fifteenN₂F₃O₃. Calculated,%: C 52.83; H, 5.38. UV spectrum (ethanol) λ_max(log ε): 213_pl(4.63), 230 (4.60), 300 (4.06); NMR spectrum¹N (DMSO-d₆): 2.18 (3H, s, 3-CH₃), 2.31 (3H, s, 2-CH₃), 3.59 (3H, s, 1-CH₃), 3.91 (3H, s, 5-OCH)₃), 7.13 (1H, s, H-4), 7.30 (1H, s, H-7), 9.44 (3H, s_{the ear}6-NH₃) ppm, NMR spectrum^nineteenF (DMSO-d₆): 73.63 ppm Mass spectrum Jm / z (% to J_max): 205 (15.12), 204 (100.00), 190 (11.31), 189 (73.67), 161 (46.65), 160 (10.21), 69 (12.31) 45 (11.61), 28 (8.41).

1H NMR spectra were recorded on a Joel JNM-ECX400 multinuclear nuclear magnetic resonance spectrometer (400 MHz) in DMSO-d ₆ . Electronic spectra were obtained on a LEKI SS2109UV instrument in ethanol. Mass spectra were recorded on a Finnigan MAT INCOS-50 mass spectrometer with direct input of the sample into an ion source at an ionization energy of 70 eV. Elemental analysis was performed on a vario MICRO cube elemental analyzer. The names of amines and salts are given according to the rules of the computer program ACD / LABS IUPAC Name Generator. Structural formulas of compounds are drawn in the ISIS Draw 2.4 computer program. The purity of the obtained compounds was monitored, R _f was determined by TLC on Silufol UV-254 plates in a 1: 1: 0.1 benzene-ethyl acetate-methanol system.

The antimicrobial activity of 2,3,5-trimethyl-1H-indole-6-ammonium trifluoroacetate, 1,2,3,5-tetramethyl-1H-indole-6-ammonium trifluoroacetate, 2,3-dimethyl-5-methoxy trifluoroacetate was studied -1H-indole-6-ammonium, 1,2,3-trimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate.

When conducting a microbiological experiment, the studied compounds were used in the form of a solution (sterile water for injection was used as a solvent). Museum strains were used as test microorganisms for studying the antimicrobial activity of the obtained compounds: Staphylococcus aureus 6538-P ATCC, Staphylococcus aureus 43300 ATCC (МRSА), Escherichia coli 25922 ATCC, Pseudomonas aeruginosa 27853 ATCC, Streptococcus. The museum strains used in this work were obtained from the collection of the Museum of Living Cultures of FSBI “NTsESMP” of the Ministry of Health of Russia, Becton Dickinson France S.A.S. The antimicrobial activity of the obtained compounds was determined by the method of serial dilutions in the broth (“test tube” macro method) [14–16]. The antimicrobial preparation dioxidin (a derivative of di-N-hydroxyquinoxaline) (production of Biosynthesis, solution for topical application, endotracheal and intravenous administration, 10 mg / ml), widely used in medical practice, was used as a comparison drug. This drug has high in vivo chemotherapeutic activity on model infections similar in pathogenesis to human pathological processes (purulent meningitis, pyelonephritis, septicopyemia) and caused by strains of anaerobic bacteria that are resistant (including multiresistant) to drugs of other classes, including Pseudomonas aeruginosa strains sticks and methicillin-resistant staphylococci. Dioxidin is characterized by a wide antibacterial spectrum with a bactericidal effect, and is also active against gram-positive and gram-negative aerobic conditionally pathogenic bacteria. The activity of dioxidine against tuberculosis mycobacteria is shown. For the preparation of comparison of dioxidine IPC relative to strains of Staphylococcus spp. is 125.0-1000.0 μg / ml, Escherichia coli 8.0-250.0 μg / ml, Pseudomonas spp. 125.0-1000.0 μg / ml, Streptococcus spp. 64.0-1000.0 μg / ml [17].

To assess the sensitivity of microorganisms, Muller-Hinton Bouillon (ICB) was used, which is approved for use in the Russian Federation in the prescribed manner and satisfies the requirements in terms of its characteristics. Intralaboratory quality control of the environment was carried out using all the media approved for use in the Russian Federation in the established manner. The concentration of the suspension of the studied microorganism was 1.5x10 ⁸ CFU / ml. The optical density of the bacterial suspension with a concentration of 1.5x10 ⁸ CFU / ml upon visual inspection corresponded to the turbidity standard of 0.5 according to McFarland. A commercial turbidity standard was used in the work. A bacterial suspension was prepared from agar cultures. To prepare the inoculum, a pure daily culture of microorganisms grown on solid nutrient media was used. Selected several of the same type, clearly isolated colonies grown on non-selective solid nutrient media. Loops transferred a small amount of material from the tops of the colonies into a test tube with sterile saline, adjusting the inoculum density to exactly 0.5 according to the McFarland standard. Inoculum was used for 15 minutes after preparation.

Serial dilution method in broth - macro method (test tube)

Testing was carried out in a volume of 1 ml of each dilution of the test compound with a final concentration of the studied microorganism of about 5x10 ⁵ CFU / ml. MKB for determination of sensitivity was poured into 0.5 ml in each tube. The number of tubes was nine, plus one for setting a “negative” control, that is, ten. A working solution of the test compound was prepared from the main solution using a liquid nutrient medium - MBB. Then a working solution in an amount of 0.5 ml using a micropipette with a sterile tip was introduced into the first tube containing 0.5 ml of broth. The mixture was thoroughly mixed and a new sterile tip transferred 0.5 ml of a solution of the test compound in the broth to a second tube containing initially 0.5 ml of broth. This procedure was repeated until all the necessary series of dilutions was prepared. 0.5 ml of broth was removed from the last tube. Thus, a number of test tubes with solutions of the test compound were obtained, the concentrations of which differed by 2 times in neighboring tubes. For inoculation, a standard microbial suspension equivalent to 0.5 according to the McFarland standard, diluted 100 times in ICB, was used, after which the concentration of the microorganism in it was approximately 10 ⁶ CFU / ml. 0.5 ml of inoculum was added to each tube containing 0.5 ml of the appropriate dilution of the test compound, and to one tube with 0.5 ml of MCB without antibiotic (“negative” control). The final concentration of the microorganism in each tube was approximately 5x10 ⁵ CFU / ml. The inoculum was introduced into test tubes with dilutions of the test compound no later than 15-30 minutes from the time of preparation. The tubes were closed with sterile cotton-gauze plugs and all but the “negative” control tubes were incubated in a normal atmosphere at 37 ° C for 16–20 or 20–24 h (depending on the type of microorganism being tested). The negative control tube was placed in a refrigerator at 4 ° C, where it was stored until the results were taken into account. To determine the presence of microorganism growth, test tubes with inoculations were examined in transmitted light. The culture growth in the presence of the test compound was compared with a reference tube (“negative” control) containing the original inoculum and stored in the refrigerator. The minimum inhibitory concentration (MIC) was determined by the lowest concentration of the test compound, which inhibits the visible growth of the microorganism.

Relative to test strains of microorganisms, 2,3,5-trimethyl-1H-indole-6-ammonium trifluoroacetate (X-1) shows the following activity: for S.aureus 6538-P, ATCC MPC of the test compound was 1.96 μg / ml; Staphylococcus aureus 43300 ATCC (MRSA) 1.96 μg / ml; E.coli 25922 ATCC - 0.98 μg / ml; P.aeruginosa 27853 ATCC - 0.98 μg / ml; S.pyogenes 19615 ATCC - 0.98 μg / ml; 1,2,3,5-tetramethyl-1H-indole-6-ammonium trifluoroacetate (C-1): for S. aureus 6538-P, ATCC MPC of the test compound was 7.9 μg / ml; Staphylococcus aureus 43300 ATCC (MRSA) 7.9 μg / ml; E.coli 25922 ATCC - 0.98 μg / ml; P.aeruginosa 27853 ATCC - 3.9 μg / ml; S.pyogenes 19615 ATCC - 31.3 μg / ml; 2,3-dimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate (X-2): for S. aureus 6538-P ATCC, the MPC of the test compound was 31.2 μg / ml; Staphylococcus aureus 43300 ATCC (MRSA) 31.2 μg / ml; E.coli 25922 ATCC - 0.98 μg / ml; P.aeruginosa 27853 ATCC - 7.9 μg / ml; S.pyogenes 19615 ATCC - 125 μg / ml; 1,2,3-trimethyl-5-methoxy-1H-indole-6-ammonium trifluoroacetate (C-2): for S.aureus 6538-P ATCC, the MIC of the test compound was 125 μg / ml; Staphylococcus aureus 43300 ATCC (MRSA) 125 μg / ml; E.coli 25922 ATCC - 0.98 μg / ml; P.aeruginosa 27853 ATCC - 1.96 μg / ml; S.pyogenes 19615 ATCC - 0.98 μg / ml, which exceeds the antimicrobial activity of the reference drug - dioxidine.

Thus, the compounds in the claimed invention have antimicrobial activity in excess of the activity of the reference drug - dioxidine.

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Claims (6)

The method of obtaining trifluoroacetates substituted 6-aminoindoles having antimicrobial activity, General formula (1):

, (1) where R = H, CH₃, R₁= CH₃, OCH₃, characterized in that in order to obtain water-soluble trifluoromethyl substituted aminoindole derivatives of a compound of general formula (2):

, (2) where R and R ₁ have the indicated meanings, in benzene heated to boiling, they are reacted with trifluoroacetic acid of the general formula (3):

(3)