RU2744429C1 - Anti-rna viral, including anti-coronavirus agent - substituted quinoxaline, pharmaceutical composition and applications - Google Patents

Abstract

FIELD: pharmaceutical industry, medicine.SUBSTANCE: the invention relates to a substituted quinoxaline of general formula 1, where R1and R2are optionally the same hydrogen or halogen atoms, R3is a hydrogen atom, provided that R1, R2and R3are not simultaneously hydrogen, or both R1and R2are not 6 ,7-dichloro, or if R1is hydrogen, then R2is not 7-chloro. The invention also relates to a pharmaceutical composition having the property of an inhibitor of RNA-dependent RNA polymerase (RdRp) of RNA viruses, based on the specified compound of formula 1.EFFECT: new compounds and pharmaceutical compositions based on them have been obtained, which can be used in medicine as agents that inhibit RNA-dependent RNA polymerase (RdRp) RNA viruses, where the virus is SARS-CoV-2 coronavirus and influenza virus.5 cl, 1 dwg, 1 tbl, 10 ex

Description

This invention relates to a new inhibitor of RNA-dependent RNA polymerase (RdRp) of various RNA viruses - 3-hydroxy-6-fluoro-quinoxaline-2-carboxamide to a pharmaceutical composition and methods for their preparation and use. RNA - A virus is a virus that has RNA (ribonucleic acid) as its genetic material. The most common diseases caused by RNA viruses include influenza, ebola, severe acute respiratory syndrome (ARVI, SARS), SARS-CoV-2 coronavirus, yellow fever, etc. [P. Poltronieri ct al. RNA Viruses: RNA Roles in Pathogenesis, Complication and Viral Load. Curr. Genomics. 2015,16 (5), 327-335.].

Influenza is an infectious disease caused by the influenza virus. Symptoms can range from mild to severe. Complications of influenza can include viral pneumonia, secondary bacterial pneumonia, sinus infections, and worsening of previous health problems such as asthma or heart failure. Annual outbreaks of influenza spread around the world, resulting in three to five million cases of severe illness and between 290,000 and 650,000 deaths. Larger outbreaks, known as pandemics, are less common. There were three influenza pandemics in the 20th century: the Spanish flu in 1918 (17-100 million deaths), the Asian flu in 1957 (two million deaths), and the Hong Kong flu in 1968 (one million deaths). The World Health Organization declared an outbreak of a new type of influenza A / H1N1 a pandemic in June 2009. Influenza can also affect other animals, including pigs, horses and birds [https://en.wikipedia.org/wiki/Influenza].

The US Centers for Disease Control and Prevention (CDC) recommends four anti-influenza drugs for the treatment of influenza, including: oseltamivir phosphate (trade name Tamiflu®), zanamivir (trade name Relenza®), peramivir (trade name the name Rapivab®) and baloxavir marboxil (trade name Xofluza®) [https://www.cdc.gov/flu/treatment/whatyoushould.htm]. Known anti-herbal drugs.

Also known anti-influenza drug Favipiravir (T-705, Avigan, Favilavir), patented in 1999 by the Japanese company Toyama Xmikal Co. [RU 2224520]. Favipiravir is used in Japan to treat influenza, including the highly pathogenic A H5N1 avian influenza strain [R.W. Sidwell at al. Antimicrob. Agents Chemother. 2007,51 (3): 845-851].

Favipiravir exhibits antiviral activity against many other RNA viruses such as arenaviruses, bunyaviruses and filoviruses, which are known to cause fatal hemorrhagic fever. [Y. Furuta et al. Review Favipiravir (T-705), a broad spectrum inhibitor of viral RNA polymerase. Proc. Jpn. Acad., Scr. B 93, 2017, 449-463].

Favipiravir has successfully completed a trial for the treatment of progressive Ebola virus infection in mice [L. Oestereich et al. Ebola virus infection with T-705 (favipiravir) in a small animal model. Antiviral Research 2014, 105, 17-21.] And is a promising drug candidate, but has not yet been approved by WHO.

Ebola viral disease (EVD), also known as Ebola haemorrhagic fever (EIIF) or simply Ebola, is a viral haemorrhagic fever in humans and other primates caused by ebolaviruses. The disease has a high risk of death, killing between 25% and 90% of those infected, with an average of about 50%. EVD outbreaks occur intermittently in tropical regions of sub-Saharan Africa. Between 1976 and 2013, WHO reports 24 outbreaks with 2,387 cases with 1,590 deaths. The largest outbreak to date was in West Africa, which occurred from December 2013 to January 2016, with 28,646 cases and 11,323 deaths. The Ebola vaccine was approved in the US in December 2019. As of 2019, there was no approved treatment for Ebola [https://en.wikipedia.org/wiki/Ebola_virus_disease].

In February 2020, Favipiravir was successfully tested in an initial randomized trial in China as an antiviral therapy for the SARS-CoV-2 (COVID-19) coronavirus. Favipiravir received short-term approval in China on February 16, 2020 as an effective antiviral against COVID-19 for five years. It is currently produced in China under the name Favipiravir [https://de.wikipedia.org/wiki/Favipiravir]. As of April 25, 2020, 2,837,155 COV1D-19 cases, 808,975 recovered patients and 197,698 deaths were registered in the world (for 4 months).

It should be noted that Favipiravir has at least three significant drawbacks: low micromolar activity, the need to use high doses of favipiravir in the treatment of RNA viral diseases (daily dose from 1200 mg to ≥3200 mg [https://researchgate.net/publication/340000976_Experimental_Treatment_with_FavipiraVir 19_An_Open-Label_Control_Study] and Serious Side Effects [L. Voytko. Japanese Flu Drug 'Effective' Against Coronavirus In Clinical Trials, Chinese Officials Say. Mar 18, 2020. https://www.forbes.com/sites/lisettevoytko/2020/ 03/18 / japanese-flu-drug-effective-against-coronaviras-in-clinical-trials-chinese-officials-say / # 7e5300b56bad].

In our opinion, all these shortcomings are associated with its dramatic chemical lability [J. Huchting et al. Prodrugs of the Phosphoribosylated Forms of Hydroxypyrazinecarboxamide Pseudobase T-705 and Its De-Fluoro Analogue T-1105 as Potent Influenza Vims Inhibitors. J. Med, Chem. 2018, 61, 6193-6210], due to the presence of fluorine, which can easily enter into nucleophilic substitution reactions. Even in pure water and aqueous media, nucleophilic substitution of fluorine for hydroxyl occurs, followed by decomposition of the pyrazine heterocycle T-705 [J. Huchting et al. Synthesis of T705-ribonucleoside and T-705-ribonucleotide and studies of chemical stability. ChemMedChem 2017,12,652-659]. In addition, the highly reactive fluorine atom of Favipiravir can be easily replaced by O-, N- and S-nucleophiles, for example, cysteine or lysine in proteins [S.B. Cohen, R.L. Halcomb. Synthesis and characterization of an anomeric sulfur analogue of CMP-sialic acid. J. Org. Chem. 2000, 65, 6145-52], and non-selective or poorly selective covalent binding of such agents to biomolecules can lead to severe damage to cells and tissues or activation of the innate immune system in response to the formation of modified proteins that are considered foreign, with subsequent degradation in lysosomes. In addition, many irreversible inhibitors have mutagenic and genotoxic effects [J. Kazius et al. Derivation and validation of toxicophores for mutagenicity prediction. J. Med. Chem. 2005, 48, 312-20].

Considering that RNA viruses, and especially coronaviruses, pose a serious threat to public health (on a global scale, annual epidemics lead to 3-5 million cases of severe illness, millions of hospitalizations and up to 650,000 deaths worldwide), it seems advisable to search for new anti-RNA viral drugs with improved characteristics.

The following are definitions of terms that are used in the description of this invention.

The term "prodrug" refers to compounds of the invention that are cleaved chemically or metabolically and become, by solvolysis or under physiological conditions, a compound of the present invention that is pharmaceutically active in vivo. Prodrugs often have higher solubility, tissue compatibility, delivery, or sustained release in mammals (Bungard, H., Desing of products, pp. 7-9, 21-24, Elsevier, Amsterdam 1985). Prodrugs include acid derivatives well known to those skilled in the art, such as, for example, esters prepared by reacting an acidic parent compound with a suitable alcohol, or amides prepared by reacting a parent acid compound with a suitable amine. Examples of prodrugs include, but are not limited to, acetate, formate, benzoate, or other acylated derivatives of alcohols or amine functional groups in the compounds of the present invention.

The term "active ingredient" (drug substance) refers to a physiologically active substance of synthetic or other (biotechnological, plant, animal, bactericidal, etc.) origin with pharmacological activity, which is an active ingredient of a pharmaceutical composition.

The term "drug" means a substance (or a mixture of substances in the form of a pharmaceutical composition) in the form of tablets, capsules, injections, ointments and other ready-made forms, intended for the restoration, correction or change of physiological functions in humans and animals, as well as for the treatment and disease prevention, diagnostics, anesthesia, contraception, cosmetology and others.

The term "pharmaceutical composition" means a composition comprising a compound of Formula 1 and at least one of the components selected from the group consisting of pharmaceutically acceptable and pharmacologically compatible excipients, solvents, diluents, carriers, auxiliary, dispensing and receiving agents, delivery devices such as preservatives, stabilizers, fillers, grinders, humectants, emulsifiers, suspending agents, thickeners, sweeteners, fragrances, flavorings, antibacterial agents, fungicides, lubricants, sustained delivery regulators, the choice and ratio of which depends on the nature and method of administration and dosage. Examples of suspending agents are ethoxylated isostearyl alcohol, polyoxyethylene, sorbitol and sorbitol ether, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, and mixtures of these substances. Protection against the action of microorganisms can be provided by a variety of antibacterial and antifungal agents such as parabens, chlorobutanol, sorbic acid, and the like. The composition may also include isotonic agents such as sugars, sodium chloride and the like. Prolonged action of the composition can be provided by agents that slow down the absorption of the active ingredient, for example, aluminum monostearate and gelatin. Examples of suitable carriers, solvents, diluents and delivery vehicles are water, ethanol, polyalcohols, as well as mixtures thereof, vegetable oils (such as olive oil) and injectable organic esters (such as ethyl oleate). Examples of fillers are lactose, milk sugar, sodium citrate, calcium carbonate, calcium phosphate, and the like. Examples of grinders and dispensers are starch, alginic acid and its salts, silicates. Examples of lubricants are magnesium stearate, sodium lauryl sulfate, talc, and high molecular weight polyethylene glycol. A pharmaceutical composition for oral, sublingual, transdermal, intramuscular, intravenous, subcutaneous, local or rectal administration of an active ingredient, alone or in combination with another active ingredient, can be administered to animals and humans in a standard administration form, as a mixture with traditional pharmaceutical carriers. Suitable unit forms of administration include oral forms such as tablets, gelatin capsules, pills, powders, granules, chewing gums and oral solutions or suspensions, sublingual and buccal administration forms, aerosols, implants, topical, transdermal, subcutaneous, intramuscular, intravenous, intranasal or intraocular administration forms and rectal administration forms.

The term "excipient" as used herein refers to a compound that is used to prepare a pharmaceutical composition and is generally safe, non-toxic, and neither biologically nor otherwise undesirable, and includes excipients that are acceptable to veterinary use as well as pharmacologically acceptable for human use. The compounds of this invention may be administered alone, but will usually be administered in admixture with one or more pharmaceutically acceptable excipients, diluents or carriers selected based on the intended route of administration and standard pharmaceutical practice.

The term "pharmaceutically acceptable salt" means the relatively non-toxic organic and inorganic salts of acids and bases as claimed in the present invention. These salts can be obtained in situ during the synthesis, isolation, or purification of compounds, or they can be specially prepared. In particular, base salts can be specially prepared starting from the purified free base of the claimed compound and a suitable organic or inorganic acid. Examples of the salts thus obtained are hydrochlorides, hydrobromides, sulfates, bisulfates, phosphates, nitrates, acetates, oceanates, valeriates, oleates, palmitates, stearates, laurates, borates, benzoates, lactates, tosylates, citrates, maleates, fumarates, succinates, tartrates mesylates, malonates, salicylates, propioates, ethanesulfonates, benzenesulfonates, sulfamates and the like (For a detailed description of the properties of such salts, see Berge SM, et al., "Pharmaceutical Salts" J. Pharm. Sci. 1977, 66: 1-19). Salts of the claimed acids can also be specially prepared by reacting a purified acid with a suitable base, whereby metal and amine salts can be synthesized. Metallic salts include sodium, potassium, calcium, barium, zinc, magnesium, lithium and aluminum salts, the most desirable of which are sodium and potassium salts. Suitable inorganic bases from which metal salts can be derived are sodium hydroxide, carbonate, bicarbonate and hydride, potassium hydroxide and bicarbonate, potash, lithium hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide. As organic bases from which the salts of the claimed acids can be obtained, amines and amino acids are selected that are basic enough to form a stable salt and are suitable for medical use (in particular, they must have low toxicity). Such amines include ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, benzylamine, dibenzylamine, dicyclohexylamine, piperazine, ethylpiperidine, tris (hydroxymethyl) aminomethane, and the like. In addition, tetraalkylammonium hydroxides such as choline, tetramethylammonium, tetraethylammonium and the like can be used for salt formation. Basic amino acids - lysine, ornithine and arginine - can be used as amino acids.

The term "crystalline form" means a structure of a substance characterized by the packing of its constituent molecules into one of the types of a crystal lattice.

The term "polycrystalline form" means a structure of a substance having a polycrystalline structure, i. E. consisting of many small single crystals, i.e. crystallites of a certain crystalline form.

The term "therapeutically effective amount" as used herein means the amount of a substance, prodrug, or drug required to reduce the symptoms of a disease in a subject. The dose of a substance, prodrug or drug will be tailored to the individual requirements in each case. This dose can vary widely depending on numerous factors such as the severity of the disease to be treated, the age and general health of the patient, other drugs with which the patient is being treated, the route and form of administration, and the experience of the attending physician. For oral administration, the daily dose is about 0.01 to 10 g, including all values in between, per day in monotherapy and / or in combination therapy. The preferred daily dosage is from about 0.1 to 7 g per day. Typically, treatment is started with a large initial “loading dose” to rapidly reduce or eliminate the virus accompanying the tapering dose to a level sufficient to prevent an outbreak of infection.

The term "solvate" means a complex or aggregate formed by one or more molecules of a solute, i. E. a compound of the invention or a pharmaceutically acceptable salt thereof and one or more solvent molecules. Such solvates are typical solid crystals having a substantially fixed solute to solvent molar ratio. Representative solvents include, but are not limited to, water, ethanol, isopropanol, acetic acid, etc. When the solvent is water, the formed solvate is a hydrate.

The term "subject" means a mammal that includes, but is not limited to, cattle, pigs, sheep, chickens, turkeys, buffaloes, llamas, ostriches, dogs, cats and humans, preferably the subject is a human. It is assumed that the method of treating a subject can be any of the prodrugs of general formula 1, its stereoisomer, isotopically enriched analogue, its pharmaceutically acceptable salt, hydrate, solvate, crystalline and polymorphic form, or in combination with another compound, including an inhibitor of RNA-dependent RNA polymerase (RdRp) of various RNA viruses.

The authors discovered a new viral anti-RNA, including an anti-coronavirus agent, which is a substituted quinoxaline of general formula 1, its stereoisomer, a pharmaceutically acceptable salt, amorphous, polycrystalline or crystalline form.

where: R ¹ and R ² are optionally the same hydrogen or halogen atoms; R ³ represents a hydrogen atom or a fragment of general formula 2 or its stereoisomer.

where: X represents an oxygen atom or a C = CH ₂ group; * - the place of attachment of fragment 2;

R ⁴ represents a hydrogen atom or a substituent of general formula 3 or its stereoisomer

where: * - the place of attachment of substituent 3;

R ⁵ is C ₁ -C ₆ alkyl or C ₃ -C ₆ cycloalkyl; R ⁶ is optionally substituted aryl, preferably phenyl.

Substituted quinoxaline selected from the range of:

3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (1)},

6-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (2)},

7-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (3)},

6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (4)},

5,8-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (5)}.

Also preferred are substituted quinoxaline selected from the series

3-oxo-4-b-D-ribofuranoside-3,4-dihydroquinoxaline-2-carboxamide of general formula {2.1},

4- (2-C-methyl-b-D-ribofuranosyl) -3-oxo-3,4-dihydroquinoxaline-2-carboxamide of general formula {2.2}.

More preferred is a substituted quinoxaline selected from:

3-oxo-4-b-D-ribofuranoside-3,4-dihydroquinoxaline-2-carboxamide {2.1 (1)},

6-fluoro-3-oxo-4-b-D-ribofuranoside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (2)},

7-fluoro-3-oxo-4-b-D-ribofuranoside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (3)},

6,7-fluoro-3-oxo-4-b-D-ribofuranoside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (4)},

5,8-fluoro-3-oxo-4-b-D-ribofuranoside-3,4-dihydroquinocealin-2-carboxamide {2.1 (5)},

4- (2-C-methyl-b-D-ribofuranosyl) -3-oxo-3,4-dihydroquinoxaline-2-carboxamide {2.2 (1)},

Also preferred are substituted quinoxaline selected from:

1- (C1-Salkyl) (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxalin-1 (2H) -yl) - 3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (aryloxy) phosphoryl] amino} propanoate {3.2.1},

1- (C1-C6alkyl) (2S) -2 - {[(S) - {[(2R, 3R, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxalin-1 (2H) -yl) - 3,4-dihydroxy-4-difluoro-3-hydroxytetrahydrofuran-2-yl] methoxy} (aryloxy) phosphoryl] amio} propanoate {3.2.2} or their stereoisomers.

where R ¹ , R ² have the above meaning. R ⁹ and R ¹⁰ respectively have the above meanings for R ⁵ and R ⁶ .

More preferred are substituted quinoxaline selected from the series: 1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxaline-1 (2H ) -yl) -3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.1 (1)},

1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-7-fluoro-2-oxoquinoxalin-1 (2H) -yl) - 3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.1 (2)},

1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-6,7-difluoro-2-oxoquinoxalin-1 (2H) -yl ) -3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.1 (3)},

cyclohexyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-6,7-difluoro-2-oxoquinoxalin-1 (2H) -yl) - 3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.1 (4)} or their stereo isomers, pharmaceutically acceptable salts, amorphous, polycrystalline or crystalline forms.

A new viral anti-RNA, including an anti-coronavirus agent, which is a substituted quinoxaline of general formula 1, is more active than the well-known Favipiravir, which is active against a number of RNA viruses. For example, 7-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (3)} has an EC ₅₀ activity of 2.5 μM against the highly pathogenic strain Ia / duck / MN / 1525/81 (H5N1) RNA influenza virus, while Favipiravir has EC ₅₀ = 4.5 μM for this RNA virus [RW Sidwell at al. Antimicrob. Agents Chemother. 2007, 51 (3): 845-851], i.e. the latter is 1.8 times less active than the new inhibitor of this invention. In addition, Favipiravir has a higher cytotoxicity and (CC ₅₀ > 661 μM) [RW Sidwell at al. Antimicrob. Agents Chemother. 2007, 51 (3): 845-851] and the therapeutic index TI CC ₅₀ / EC ₅₀ > 147, significantly inferior to 6-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide (1 (2)} (CC ₅₀ > 1207 μM, TI> 480).

The study of the antiviral activity of 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (4)} in an in vitro model of the SARS-COV-2 virus (strain BetaCoV / Hong Kong / VM20001061 / 2020) demonstrated pronounced anti-RNA viral activity. At a concentration of 100 μM, 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (4)} reduced the copy number of SARS-Cov-2 RNA by 2 orders of magnitude, and also completely protected cells from cytopathic action virus. Under the same conditions, Favipiravir did not affect the reproduction of the virus.

In addition, substituted quinoxalines of general formula 1 are stable in the pH range 2 ÷ 4, while Favipiravir is unstable at pH 2 and pH 4 (Table 1).

The subject of this invention is a pharmaceutical composition, in the form of tablets, capsules or injections, having the property of an inhibitor of RNA-dependent RNA polymerase (RdRp) RNA virus, containing in a therapeutically effective amount substituted quinoxaline of general formula 1 or its stereoisomer, pharmaceutically acceptable salt, amorphous, polycrystalline or a crystalline form, optionally in combination with a pharmaceutically acceptable carrier or excipient.

Pharmaceutical compositions can include pharmaceutically acceptable excipients. Pharmaceutically acceptable agents are understood as meaning diluents, auxiliary agents and / or carriers used in the pharmaceutical field. If necessary, the use of the pharmaceutical composition of the present invention in clinical practice, it can be mixed with conventional pharmaceutical carriers.

The carriers used in the pharmaceutical compositions of the present invention are those used in the pharmaceutical field to produce common forms, including: in oral forms, binders, lubricants, disintegrants, solvents, diluents, stabilizers, suspending agents, colorless agents, flavoring agents; antiseptic agents, solubilizers, stabilizers are used in injection forms; in local forms, bases, diluents, lubricants, antiseptic agents are used.

The subject of this invention is also a drug with anti-RNA viral activity, in the form of tablets, capsules or injections, placed in a pharmaceutically acceptable package, intended for the prevention of treatment of RNA viral infections in humans and warm-blooded animals, which includes a substituted quinoxaline of the general formula 1, its stereoisomer, pharmaceutically acceptable salt, amorphous, polycrystalline or crystalline form, or a pharmaceutical composition comprising a substituted quinoxaline of general formula 1, its stereoisomer, pharmaceutically acceptable salt, amorphous, polycrystalline or crystalline form.

The subject of this invention is also therapeutic cocktails for the treatment of RNA viral infections, comprising as one of the components a drug or pharmaceutical composition according to the present invention, containing as an active component a substituted quinoxaline of general formula 1, its stereoisomer, a pharmaceutically acceptable salt, amorphous, polycrystalline or crystalline form. A therapeutic cocktail for the treatment of RNA viral infections, along with the drug of the present invention, may include other known drugs intended for the treatment of RNA viral infections, or drugs that enhance the patient's immune system, including interferons.

In accordance with this invention, a method for the prevention and treatment of RNA viral infections in animals and humans consists in administering to a patient a drug, pharmaceutical composition or therapeutic cocktail according to this invention.

Medicines can be administered via an inhaler, orally, or parenterally (eg, intravenously, subcutaneously, intraperitoneally, or topically). The clinical dosage of substituted quinoxaline of general formula 1 or its stereoisomer, pharmaceutically acceptable salt, amorphous, polycrystalline or crystalline form in patients can be adjusted depending on the therapeutic efficacy and bioavailability of the active ingredients in the body, the rate of their metabolism and excretion from the body, as well as depending on the age, sex and stage of the patient's disease, while the daily dose in adults is usually 100 ÷ 4000 mg. Therefore, during the preparation of the drug according to the present invention from the pharmaceutical composition in the form of dosage units, it is necessary to take into account the above effective dosage, while each dosage unit of the drug should contain 100-4000 mg of substituted quinoxaline of general formula 1 or its stereoisomer, pharmaceutically acceptable salt, amorphous, polycrystalline or crystalline form. As directed by your doctor or pharmacist, these drugs can be taken several times over specific periods of time (preferably one to six times).

The subject of this invention is also a substituted quinoxaline of general formula 1, its stereoisomer, pharmaceutically acceptable salt, amorphous, polycrystalline or crystalline form, excluding 3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (1)}

where: R ¹ and R ² are optionally the same hydrogen or halogen atoms, excluding R ¹ = R ² = H; R ³ represents a hydrogen atom or a fragment of general formula 2 or its stereoisomer.

where: X represents an oxygen atom or a C = CH ₂ group; * - the place of attachment of fragment 2; R ⁴ represents a hydrogen atom or a substituent of general formula 3 or its stereoisomer

where: * - the place of attachment of substituent 3; R ⁵ is C ₁ -C ₆ alkyl or C ₃ -C ₆ cycloalkyl; R ⁶ is optionally substituted aryl, preferably phenyl.

Substituted quinoxaline selected from the range of:

3-oxo-3,4-dihydroquinoxaline-2-carboxamide (1 (1)}, 6-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (2)},

7-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (3)},

6,7-difluoro-3-oxo-3,4-dihydroquinoxatin-2-carboxamide {1 (4)},

5,8-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (5)}.

Also preferred are substituted quinoxaline selected from the series 3-oxo-4-β-D-ribofuranoside-3,4-dihydroquinoxaline-2-carboxamide of general formula {2.1},

4- (2-C-methyl-β-D-ribofuranosyl) -3-oxo-3,4-dihydroquinoxaline-2-carboxamide of general formula {2.2}.

More preferred is a substituted quinoxaline selected from:

3-oxo-4-β-D-ribofuranoside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (1)},

6-fluoro-3-oxo-4-β-D-ribofuranoside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (2)},

7-fluoro-3-oxo-4-β-D-ribofuranoside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (3)},

6,7-fluoro-3-oxo-4-β-D-ribofuranoside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (4)},

5,8-fluoro-3-oxo-4-β-D-ribofuranoside-3,4-diadroquinoxalin-2-carboxamide {2.1 (5)},

4- (2-C-methyl-β-D-ribofuranoside) -3-oxo-3,4-dihydroquinoxaline-2-carboxamide (2.2 (1)},

Also preferred are substituted quinoxaline selected from:

1- (C1-Calkyl) (2S) -2 - {[(S) - {[(2R, 3, S, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxalin-1 (2H) -yl ) -3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (aryloxy) phosphoryl] amino} propanoate {3.2.1},

1- (C1-C6alki) (2S) -2 - {[(S) - {[(2R, 3R, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxalin-1 (2H) -yl) - 3,4-dihydroxy-4-difluoro-3-hydroxytetrahydrofuran-2-yl] methoxy} (aryloxy) phosphoryl] amino} propanoate {3.2.2} or their stereoisomers.

where R ¹ , R ² have the above meaning, R ⁹ and R ¹⁰ have the corresponding above meaning for R ⁵ and R ⁶

More preferred are substituted quinoxaline selected from the series: 1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxachin-1 (2H ) -yl) -3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate (3.2.1 (1)},

1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-7-fluoro-2-oxoquinoxalin-1 (2H) -yl) - 3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate (3.2.1 (2)},

1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-6,7-difluoro-2-oxoquinoxalin-1 (2H) -yl ) -3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate (3.2.1 (3)},

cyclohexyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-6,7-difluoro-2-oxoquinoxalin-1 (2H) -yl) - 3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate (3.2.1 (4)},

1-methylethyl (2S) -2 - ([(S) - {[(2R, 3R, 4R, 5R) -5- (3-carbamoyl-6,7-difluoro-2-oxoquinoxalin-1 (2H) -yl ) -3,4-dihydroxy-4-methyltetrahydrofuran-2-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.2 (1)} or their stereoisomers, pharmaceutically acceptable salts, amorphous, polycrystalline or crystalline forms ...

The subject of this invention is a method for preparing 3-oxo-3,4-dihydroquinoxaline-2-carboxamide of the general formula 1, excluding 3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (1)}, by reacting C1-C4-alkyl 3-oxo-3,4-dihydroquinoxaline-2-carboxylate of general formula B1

where R ¹ and R ² have the above meaning, excluding R ¹ = R ² = H.

The subject of this invention is a process for the preparation of 3-oxo-3,4-dihydroquinoxaline-2-carboxamide of the general formula 2.1-2.7 or their stereoisomers. As the initial building blocks, we used, on the one hand, 3-oxo-3,4-dihydroquinoxaline-2-carboxyamide of general formula 1a or its trimethylsilyl derivative of general formula 1b (Scheme 1), and on the other hand, sugars 2.1-2.7 (Scheme 2 )

where: R ¹ and R ² have the above meaning

Scheme 1. Substituted 3-oxo-3,4-dihydroquinoxaline-2-carboxamides 1a and 1b.

Scheme 2. Initial building blocks 2.1, 2.2.

The method for preparing substituted 3-oxo-3,4-dihydroquinoxaline-2-carboxamide of general formula 2.1 and general formula 3.2.1 is shown in Scheme 3 and consists in the interaction of tetra-O-acetyl-β-D-ribofuranose (B2.1) with trimethylsilyl derivative of 3-oxo-3,4-dihydroquinoxalin-2-carboxamide of general formula 1b, followed by removal of acetyl protecting groups from B2.1.1 and reaction of the resulting 2.1 with 2,2-dimstoxyproian in the presence of p-toluenesulfonic acid monohydrate, followed by interaction of the resulting B2. 1.2 c (S) -isopropyl 2 - ((S) - (perfluorophenoxy) (phenoxy) phosphorylamino) propanoate in the presence of t-BuMgCl to obtain B2.1.3 and the conversion of the latter under the action of TFA into the target product of general formula 3.2.1.

R ¹ , R ² , R ⁹ and R ¹⁰ have the above meanings.

Scheme 3. Scheme for the preparation of substituted 3-oxo-3,4-dihydroquinoxaline-2-carboxamide of general formulas 2.1 and 3.2.1. a - SnCl ₄ , MeCN; b - NH ₃ , MeOH; c - Me ₂ C (OMe) ₂ , TsOH, Me ₂ CO; d - t-BuMgCl, (S) -isoproiyl 2 - ((S) - (perfluorophenoxy) (phenoxy) phosphorylamino) propanoate, THF, 0-10 ° C; e - TFA, H ₂ O, MeOH.

The method for preparing substituted 3-oxo-3,4-dihydroquinoxaline-2-carboxamide of general formula 2.2 and general formula 3.2.2 is presented in Scheme 4 and consists in the reaction (2S, 3R, 4R, 5R) -2,4-bis (benzoyloxy ) -5 - [(benzoyloxy) methyl] -3-methyloxalan-3-yl benzoate (B2.2) with trimethylsilyl derivative of 3-oxo-3,4-dihydroquinoxaline-2-carboxamide of general formula 1b, followed by deprotection of benzoyl groups from B2.2.1 and the reaction of the resulting 2.2 with 2,2-dimethoxypropane in the presence of p-toluenesulfonic acid monohydrate, followed by the reaction of the resulting B2.2.2 with (S) -isopropyl 2 - ((S) - (perfluorophenoxy) (phenoxy) phosphorylamino) -propanoate in in the presence of t-BuMgCl to obtain B2.2.3 and the conversion of the latter under the action of TFA into the target product of general formula 3.2.2.

R ¹ , R ² , R ⁹ and R ¹⁰ have the above meanings.

Scheme 4. Scheme for the preparation of substituted 3-oxo-3,4-dihydroquinoxaline-2-carboxamide of general formulas 2.2 and 3.2.2. a - SnCl ₄ , MeCN; b - NH ₃ , MeOH; c - Me ₂ C (OMe) ₂ , TsOH, Me ₂ CO; d - t-BuMgCl, (S) -isopropyl 2 - ((S) - (perfluorophenoxy) (phenoxy) phosphorylamino) propanoate, THF, 0-10 ° C; e - TFA, H ₂ O, MeOH.

The invention is illustrated by the following drawings

Figure 1. Concentration dependence of SARS-Cov-2 virus inhibition by 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (4)}.

This invention is illustrated but not limited by the following examples.

Example 1 Preparation of 6-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide of formula {1 (2)}. Ethyl 6-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxylate {B1 (1): R = Et, R ¹ = H, R ² = F} (0.236 g, 1 mmol) was stirred in a closed tube with 2.5 ml of 7N methanolic NH ₃ solution at 50 ° C. within 15 hours. After cooling, the yellow precipitate was filtered off, washed with ether and dried in a vacuum. Get 1 (2): ¹ H NMR (DMSO-d ₆ , 400 MHz) δ 12.77 (brs, 1H), 8.52 (brs, 1H), 7.84 (brs, 1H), 7.69 (dd, J ₁ = 8.8 Hz, J ₂ = 2.4 Hz, 1H), 7.54 (dt, J ₁ = 8.8 Hz, J ₂ = 2.4 Hz, 1H), 7.37 (dd, J ₁ = 8.8 Hz, J ₂ = 5.2 Hz, 1H).

Example 2. Preparation of 7-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide of formula {1 (3)}. Received, as in example 1, starting from ethyl 7-fluoro-3-oxo-3,4-dihydroquixaline-2-carboxylate {(B1 (2): R = Et, R ¹ = F, R ² = H} and ammonia. 1 (3): ¹ H NMR (DMSO-d ₆ , 400 MHz) δ 12.77 (brs, 1H), 8.52 (brs, 1H), 7.84 (brs, 1H), 7.69 (dd, J ₁ = 8.8 Hz, J ₂ = 2.4 Hz, 1H), 7.54 (dt, J ₁ = 8.8 Hz, J ₂ = 2.4 Hz, 1H), 7.37 (dd, J ₁ = 8.8 Hz, J ₂ = 5.2 Hz, 1H).

Example 3. Obtaining ethyl 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxylate {B1 (3): R = Et, R ¹ = R ² = F}. To a solution of 4,5-difluorobenzene-1,2-diamine (10 mmol) in EtOH (30 ml) was added diethyl ketomalonate (1.74 g, 10 mmol) and refluxed for 2 hours. After cooling, the reaction mixture was concentrated and treated with ethyl acetate. The precipitate was collected by filtration, washed with ethyl acetate, ether and dried in vacuum, yielding B1 (3): ¹ H NMR (DMSO-d ₆ , 400 MHz) δ 12.98 (brs, 1H), 8.01 (dd, J ₁ = 10.8 Hz, J ₂ = 8.0 Hz, 1H), 7.27 (dd, J ₁ = 10.8 Hz, J ₂ = 7.2 Hz, 1H), 4.37 (q, J = 7.0 Hz, 2H), 1.31 (t, J = 7.0 Hz, 3H) ...

Example 4 Preparation of 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (4)}. Prepared as in example 1 starting from ethyl 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxylate {B1 (3)} and ammonia. 1 (4): ¹ H NMR (DMSO-d ₆ , 400 MHz) δ 12.77 (brs, 1H), 8.52 (brs, 1H), 7.84 (brs, 1H), 7.69 (dd, J ₁ = 8.8 Hz, J ₂ = 2.4 Hz, 1H), 7.54 (dt, J ₁ = 8.8 Hz, J ₂ = 2.4 Hz, 1H), 7.37 (dd, J ₁ = 8.8 Hz, J ₂ = 5.2 Hz, 1H).

Example 5. Obtaining 3-oxo-4-β-D-ribofunaroside-3,4-diadroquinoxalin-2-carboxamide of the general formula {2.1} and 4- (2-C-methyl-β-D-ribofuranoside) -3-oxo -3,4-dihydroquinoxaline-2-carboxamide of general formula {2.2}.

N, O-bis (trimethylsilyl) acetamide (0.856 ml, 3.5 mmol) was added to a suspension of compound 1b (1 mmol) in 10 ml of dry acetonitrile under argon, and the mixture was stirred for 2 hours at 50 ° С. The solution is cooled and the corresponding ribofuranose (1.1 mmol) and tin (IV) chloride (0.176 ml, 1.5 mmol) are added. The mixture is stirred under argon at 70 ° C for 15 hours. The solution was evaporated in vacuo, diluted with dichloromethane, washed with water and saturated NaHCO ₃ , dried over Na ₂ SO ₄ and evaporated in vacuo. The target product is isolated by column chromatography on silica gel (dichloromethane: methanol 19: 1).

An ice-cold 4N solution of ammonia in methanol was added to the resulting product, and the mixture was stirred in a refrigerator for 12 hours. The solution was evaporated, the residue was treated with acetonitrile. The precipitate is filtered off, washed with acetonitrile, ether and dried under vacuum. Receive respectively the target product of General formula 2.1 or 2.2, including: 3-oxo-4-β-D-ribofunaroside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (1)}, Mol. wt 321, LC-MS (ESI) 322 (M + H) ⁺ ; 6-fluoro-3-oxo-4-β-D-ribofunaroside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (2)}, Mol. wt 341, LC-MS (ESI) 342 (M + H) ⁺ ; 7-fluoro-3-oxo-4-β-D-ribofuranoside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (3)}, Mol. wt 341, LC-MS (ESI) 342 (M + H) ⁺ ; 6,7-fluoro-3-oxo-4-β-D-ribofunaroside-3,4-dihydroquinoxalin-2-carboxamide {2.1 (4)}, Mol. wt 357, LC-MS (ESI) 348 (M + H) ⁺ ; 5,8-fluoro-3-oxo-4-β-D-ribofunaroside-3,4-dihydroquinocealin-2-carboxamide {2.1 (5)}, Mol. wt 357, LC-MS (ESI) 348 (M + H) ⁺ ; 4- (2-C-methyl-β-D-ribofuranoside) -3-oxo-3,4-dihydroquinoxaline-2-carboxamide {2.2 (1)}, Mol. wt 335, LC-MS (ESI) 336 (M + H) ⁺ .

Example 6. Obtaining 1- (C1-C6alki) (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxalin-1 (2H) -yl) -3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (aryloxy) phosphoryl] amino} propanoate of general formula {3.2.1} and 1- (C1-C6alki) (2S) -2 - {[(S ) - {[(2R, 3R, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxalin-1 (2H) -yl) -3,4-dihydroxy-4-difluoro-3-hydroxytetrahydrofuran-2-yl } methoxy} (aryloxy) phosphoryl] amino} propanoate of general formula {3.2.2}.

To a suspension of compound 2.1 or 2.2 (1 mmol) in 10 ml of acetone, 2,2-dimethoxypropane (1.23 ml, 10 mmol) and n-toluenesulfonic acid monohydrate (0.228 g, 1.2 mmol) are added, and the mixture is stirred at room temperature for 15 h. The mixture was evaporated in vacuo, dissolved in methanol, treated with Amberlit A-26 in alkaline form (pre-washed with 2N NaOH and water) and stirred for 2 hours. The mixture was filtered, evaporated in vacuo, the residue was washed with ethyl acetate, dried in vacuum and obtained, respectively. .2.1.2 or B.2.2.2.

To a solution of compound B.2.1.2 or B.2.2.2 (1 mmol) in 10 ml of THF under argon at a temperature of -10-0 ° C add a 1M solution of tert-butyl magnesium chloride in THF (2.25 ml, 2.25 mmol), maintaining the temperature of the mixture is below 0 ° C. The reaction mixture is stirred under argon at a temperature of about 0 ° C for 1 hour.Then (S) -isopropyl 2 - ((S) - (perfluorophenoxy) (phenoxy) phosphorylamino) propanoate (0.63 g , 1.2 mol) and the mixture was stirred under argon at room temperature for 15 h. The reaction mixture was diluted with dichloromethane, washed with 5% citric acid solution with 10% NaCl, and evaporated in vacuum. Dissolve the residue B.2.1.3 or B.2.2.3 in 8 ml of TFA, add 2 ml of water and stir for 30 min. The solution is evaporated in vacuum and the target product of general formula 3.2.1 or 3.2.2 is isolated by HPLC, including: 1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-2-oxoquinoxalin-1 (2H) -yl) -3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.1 (1)}, Like. wt 590, LC-MS (ESI) 591 (M + H) ⁺ ;

1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-7-fluoro-2-oxoquinoxalin-1 (2H) -yl) - 3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.1 (2)}, Mol. wt 608, LC-MS (ESI) 681 (M + H) ⁺ ; 1-methylethyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-6,7-difluoro-2-oxoquinoxalin-1 (2H) -yl ) -3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.1 (3)}, Mol. wt 626, LC-MS (ESI) 627 (M + H) ⁺ ; cyclohexyl (2S) -2 - {[(S) - {[(2R, 3S, 4R, 5R) -5- (3-carbamoyl-6,7-difluoro-2-oxoquinoxalin-1 (2H) -ip) - 3,4-dihydroxytetrahydrofuran-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.1 (4)}, Mol. wt 666, LC-MS (ESI) 667 (M + H) ⁺ ; 1-methylethyl (2S) -2 - {[(S) - {[(2R, 3R, 4R, 5R) -5- (3-carbamoyl-6,7-difluoro-2-oxohyioxachin-1 (2H) -yl ) -3,4-di-hydroxy-4-methyltetrahydrofuran-2-2-yl] methoxy} (phenoxy) phosphoryl] amino} propanoate {3.2.2 (1)}, Mol. wt 604, LC-MS (ESI) 605 (M + H) ⁺ .

Example 7. Obtaining a pharmaceutical composition in the form of tablets. 1600 mg of starch, 1600 mg of crushed lactose, 400 mg of talc and 1000 mg of 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide are mixed {1 (1), 1 (3) or 1 (4) }. The resulting bar is crushed into granules and sieved through sieves, collecting granules with a size of 14-16 mesh. The resulting granules are tableted into a suitable tablet form weighing 920 mg, each containing 200 mg of 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (1), 1 (3) or 1 (4 )} weighing 560 mg each.

Example 8. Obtaining a pharmaceutical composition in the form of capsules. Thoroughly mix 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {3.2.1 (1), 3.2.1 (2) or 3.2.1 (3)} with lactose powder in the ratio of 2: one. The resulting powder mixture is packaged in 600 mg in gelatin capsules of a suitable size, each of which contains 200 mg of 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {3.2.1 (1), 3.2.1 ( 2) or 3.2.1 (3)}.

Example 9. Anti-RNA viral activity and cytotoxicity of 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (3)}. The anti-RNA viral activity against the Ia / duck / MN / 1525/81 strain of the influenza virus RNA of the test compound was determined at the Institute for Antiviral Research, University of Utah, using a neutral red essay. The cytotoxicity of the test compounds is determined in parallel. 7-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (3)} has an EC ₅₀ activity of 2.5 μM, a CC ₅₀ cytotoxicity> 1207 μM and a therapeutic TI> 480).

Example 10. Anti-RNA viral activity and cytotoxicity. The protocol for testing substances against the SARS-CoV-2 virus is described in the article by Ka-Tim Choy al. Remdesivir, lopinavir, emetine, and homoharringtonine inhibit SARS-CoV-2 replication in vitro. Antiviral Research 2020, 178, 10478; https://www.sciencedirect.com/science/ article / pii / S016635422030200X. The activity of the compounds was determined against the SARS-CoV-2 virus, strain BetaCoV / Hong Kong / VM20001061 / 2020, isolated from samples of patients with COVID-2019. The VERO E6 culture was seeded in a 96-well plate, incubated at 37 ° C and 5% CO2 for 24 hours. A 100 μM stock solution of the test substance in DMSO was prepared, and serial dilutions were made in DMSO with a step of 4 (to obtain 1000-fold solutions in DMSO). The corresponding amount of the stock solution of the test substance in DMSO was subjected to intermediate dilution in a medium for cell cultivation, the resulting solutions of the substance were added to the cells, the final concentration of DMSO was 0.1%. Each substance was investigated at five concentrations: 100 μM, 25 μM, 6.25 μM, 1.56 μM, 0.39 μM, and 0 (blank control) in 2 repetitions (wells). 2 hours after the addition of substances, the virus was added at MOI = 0.02, and incubated at 37 ° C and 5% CO ₂ for 48 hours. Selected 200 μl of the supernatant from the virus culture, isolated nucleic acids, used QRT-PCR to detect viral load using the TaqMan ™ Fast Virus 1-Step Master Mix kit. Received, in particular for compound 1 (4) EC ₅₀ = 29.25 μM (Figure 1). Cytotoxicity (CC ₅₀ > 100 μM) was determined in cells with added substances and without virus using the CellTiter-Glo kit (Promega).

Claims (13)

1. Substituted quinoxaline of general formula 1

, where R ¹ and R ² are optionally the same hydrogen or halogen atoms, R ³ is a hydrogen atom, provided that R ¹ , R ² and R ^{3 are} not simultaneously hydrogen, or both R ¹ and R ^{2 are} not 6,7-dichloro, or if R ¹ is hydrogen, then R ^{2 is} not 7-chloro. 2. Substituted quinoxaline according to claim 1, selected from the series 6-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (2)}, 7-fluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (3)}, 6,7-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (4)}, 5,8-difluoro-3-oxo-3,4-dihydroquinoxaline-2-carboxamide {1 (5)}

3. Substituted quinoxaline according to claim 1 or 2, having the properties of an inhibitor of RNA-dependent RNA polymerase (RdRp) of the RNA virus, where the virus is SARS-CoV-2 coronavirus and influenza virus. 4. A pharmaceutical composition having the property of an inhibitor of RNA-dependent RNA polymerase (RdRp) of an RNA virus, where the virus is a SARS-CoV-2 coronavirus and an influenza virus, containing in a therapeutically effective amount a substituted quinoxaline of general formula 1 according to claim 1 or 2 in combination with a pharmaceutically acceptable carrier or excipient. 5. The use of a substituted quinoxaline of general formula 1 according to claim 1 or 2 or a pharmaceutical composition according to claim 4 for inhibiting RNA-dependent RNA polymerase (RdRp) of an RNA virus, where the virus is SARS-CoV-2 coronavirus and influenza virus.

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