Anti-viral agent

Abstract

The present invention provides an anti-viral agent and the like including a compound represented by general formula (1) or (2) (where R1 is -(CH2)n1-Z1-R11 or -CH-(-Z1-R11)2 (n1 is 0 or 1; Z1 is a single bond, -O-, -NH-, -S-, -SO-, -SO2-, -CO-, -CO-O-, or -CH=N-O-; R11 is a hydrogen atom, a C1-6 alkyl group, -NR12R13, -N3, -NO2, -CN, -CH2-CO-O-R14, or a nitrogen atom-containing 5-membered or 6-membered heterocyclic group; R12 and R13 are each independently a hydrogen atom or a C1-6 alkyl group; and R14 is a hydrogen atom or a C1-6 alkyl group; with the proviso that, in the heterocyclic group, a nitrogen atom in the ring group is linked to Z1) or a derivative thereof, a salt of these compounds, or a solvate of these.

Description

antiviral agents

[0001] The present invention relates to an antiviral agent that is effective as a therapeutic agent against viruses such as coronaviruses and flaviviruses.

[0002] Coronaviruses are enveloped viruses whose genes are positive-sense single-stranded RNA. In addition to the viruses that cause the common cold, coronaviruses that infect humans also cause acute respiratory syndromes. Examples include SARS-CoV, which caused the severe acute respiratory syndrome (SARS) that broke out in a major outbreak in 2003, MERS-CoV, which caused the Middle East respiratory syndrome (MERS) that broke out in a major outbreak in 2013, and SARS-CoV-2, which caused the novel coronavirus disease COVID-19 that broke out in a major outbreak in 2019. In particular, there are still few treatments for COVID-19, and the development of more effective treatments is needed.

[0003] Remdesivir is a treatment for COVID-19. Remdesivir (GS-5734) is a monophosphoramidate prodrug of GS-441524, an antiviral drug consisting of a nucleic acid compound developed as a treatment for Ebola hemorrhagic fever and Marburg virus infection, and has antiviral activity against single-stranded RNA viruses. GS-441524 is also expected to have therapeutic effects against COVID-19 (Non-Patent Document 1). GS-441524 is an adenosine analog and is also the parent nucleoside of remdesivir. Non-Patent Document 5 reported that GS-441524 has antiviral activity against flaviviruses and coronaviruses. Non-Patent Document 6 reported that GS-621763 and MPV (Molnupiravir) have therapeutic effects against SARS-CoV-2 infection. GS-621763 is a prodrug of GS-441524, and MPV is a prodrug of NHC (N-hydroxycytidine).

[0004] Yan and Muller, ACS Medicinal Chemistry Letters, 2020, vol.11, p.1361-1366.Watanabe and Ueda, Nucleosides & Nucleotides, 1983, vol.2(2), p.113-125.Bergstrom et al., Journal of Organic Chemistry, 1981, vol.46(7), p.1423-1431.Uematsu and Suhadolnik, Journal of Medicinal Chemistry, 1973, vol.16(12), p.1405-1407.Cho et al., Bioorganic & Medicinal Chemistry Letters, 22(2012), 2705-2707.Schafer et al., bioRxiv preprint doi: https: / / doi.org / 10.1101 / 2021.09.13.460111, Version 9.4, 2021.9.13.Rasmussen et al., Viruses 2021, 13(7), 1369.

[0005] The present invention aims to provide an antiviral agent that is effective as a therapeutic agent for viral infectious diseases including COVID-19.

[0006] The present inventors screened compounds having antiviral activity against the novel coronavirus SARS-CoV-2 and two types of human coronavirus (strain 229E and strain OC43) using a compound library containing nucleic acid compounds as a base core held by the Center for Drug Discovery Science, Graduate School of Pharmaceutical Sciences, Hokkaido University, a national university corporation, and selected compounds with high antiviral activity, thereby completing the present invention.

[0007] That is, the present invention provides the following antiviral agents and the like: [1] A compound represented by the following general formula (1) or (2):

[0008]

[0009] [In the formula, R １ is -(CH ２) n １ -Z １ -R １１ or -CH-(-Z １ -R １１ ) ２ (n １ is 0 or 1; Z １ represents a single bond, an oxygen atom, -NH-, a sulfur atom, -SO-, or -SO ２ -, -CO-, -CO-O-, or -CH=N-O-; R １１ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -NR １２ R １３ , -N ３ , -NO ２ , -CN, -CH ２ -CO-O-R １４ or a 5- or 6-membered heterocyclic group containing a nitrogen atom; R １２ and R １３ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R １４ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. １ [2] An antiviral agent comprising a compound represented by the following general formula (1) or a derivative thereof, a salt of these compounds, or a solvate thereof: ２１ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -CH ２ -COOH or an amino group; R ２２ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an amino group; R ２３ , R ２６ , R ２７ , R ３１ , R ３２ , and R ３３ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R ２４ , R ２５ , R ２９ , R ３０ , and R ３５ is an alkyl group having 1 to 6 carbon atoms; R ２８ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a cyano group; R ３４represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -CH ２ -N ３ , a cyano group, an amino group, a nitro group, or an azido group; and A is a 5- or 6-membered heterocyclocyclic group containing a nitrogen atom.], and the general formula (2) is any one of the following general formulas (2-1) to (2-15): ２１ ~R ３５ and A is the same as defined above.] The antiviral agent according to [1],

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

[0016] [3] The antiviral agent according to [1] or [2], which comprises one or more compounds selected from the group consisting of HUP1136, HUP1108, HUP1069, HUP1077, HUP1078, and HUP1109.

[0017]

[0018] [4] A pharmaceutical composition comprising as an active ingredient the antiviral agent of any one of [1] to [3]. [5] The pharmaceutical composition of [4] above, which is used for treating an infection caused by a coronavirus or a flavivirus. [6] The pharmaceutical composition of [5] above, which is used for treating COVID-19. [7] The pharmaceutical composition of any one of [4] to [6] above, which is used in combination therapy with an inhibitor of 3CL protease. [8] The pharmaceutical composition of [7] above, wherein the inhibitor of 3CL protease is at least one selected from the group consisting of PF-07304814 and S-217622.

[0019] [9] A method for treating coronavirus infection or flavivirus infection by administering an effective amount of the antiviral agent of any of [1] to [3].

[10] The method for treatment of [9], wherein an effective amount of an antiviral agent consisting of HUP1108 is administered.

[11] The method for treatment of [9] or

[10] , wherein the effective amount is less than 60 mg / kg.

[12] The method for treatment of

[11] , wherein the effective amount is 20 mg / kg.

[13] The method for treatment of any of claims 9 to 12, wherein the coronavirus is SARS-CoV-2.

[14] The method for treatment of

[13] , wherein the SARS-CoV-2 is at least one strain selected from the group consisting of WK-521 strain, α strain, β strain, γ strain, δ strain, and o strain.

[15] The method for treatment of any one of claims 9 to 12, wherein the flavivirus is at least one selected from the group consisting of dengue virus (DENV), Zika virus (ZIKV), yellow fever virus (YFV), West Nile virus (WNV), and Japanese encephalitis virus (JEV).

[16] The method for treatment of any one of [9] to

[15] , wherein a 3CL protease inhibitor is co-administered.

[17] The method for treatment of

[16] , wherein the 3CL protease inhibitor is at least one selected from the group consisting of PF-07304814 and S-217622.

[0020]

[18] A therapeutic combination of the antiviral agent of any of [1] to [3] and an inhibitor of 3CL protease.

[19] The combination according to

[18] , wherein the inhibitor of 3CL protease is at least one selected from the group consisting of PF-07304814 and S-217622.

[20] The antiviral agent of any of [1] to [3], used for treating coronavirus infection or flavivirus infection.

[21] The antiviral agent according to

[20] , wherein the coronavirus is at least one selected from the group consisting of SARS-CoV-2 WK-521 strain, α strain, β strain, γ strain, δ strain, and O strain, and the flavivirus is at least one selected from the group consisting of dengue virus (DENV), Zika virus (ZIKV), yellow fever virus (YFV), West Nile virus (WNV), and Japanese encephalitis virus (JEV).

[0021] The antiviral agent according to the present invention contains, as an active ingredient, a nucleic acid compound that has high antiviral activity against enveloped viruses, such as coronaviruses and flaviviruses, whose genes are positive-sense single-stranded RNAs. Therefore, the antiviral agent is suitable as an in vivo or ex vivo antiviral agent, and a pharmaceutical composition containing the antiviral agent as an active ingredient is highly useful as a pharmaceutical composition for treating or preventing infectious diseases caused by coronaviruses or flaviviruses.

[0022] In Example 2, the amount of viral RNA (Log ) was measured when Caco-2 cells infected with SARS-CoV-2 were treated with any of the compounds HUP1136, HUP1108, HUP1069, HUP1077, HUP1078, and HUP1109. １０ 1 shows the results of measuring the viral RNA replication inhibition rate ([viral RNA copy number]) when Caco-2 cells infected with SARS-CoV-2 were treated with any of the compounds HUP1136, HUP1108, HUP1069, HUP1077, HUP1078, and HUP1109 in Example 2. 1 shows the results of measuring the relative viral RNA amount when Caco-2 cells infected with SARS-CoV-2 were treated with HUP1108 at three different times (Whole, Entry, and Post-entry) in Example 3. In Example 3, Caco-2 cells infected with SARS-CoV-2 were treated with HUP1108 at three different times (Whole, Entry, and Post-entry), and the viral titer (TCID ５０ In Example 5, Caco-2 cells infected with various strains of SARS-CoV-2 were treated with compound HUP1108, and the amount of viral RNA (Log １０1 shows the results of measuring the intrapulmonary virus titer of SARS-CoV-2-infected mice administered with HUP1108 and SARS-CoV-2-infected mice not administered with HUP1108 in Example 6. 1 shows the results of measuring the survival rate of SARS-CoV-2-infected mice administered with HUP1108 and SARS-CoV-2-infected mice not administered with HUP1108 in Example 7.

[0023] In the present invention and the present specification, "C ｙ－ｚ (y and z are positive integers satisfying y<z) means that the number of carbon atoms is y or more and z or less.

[0024] The antiviral agent according to the present invention comprises a compound represented by the following general formula (1) (hereinafter, sometimes referred to as "compound (1)") or a compound represented by the following general formula (2) (hereinafter, sometimes referred to as "compound (2)"):

[0025]

[0026] In the general formula (1) and the general formula (2), R １ is -(CH ２ ) n １ -Z １ -R １１ or -CH(-Z １ -R １１ ) ２ where n １ is 0 or 1, and Z １ represents a single bond, an oxygen atom, -NH-, a sulfur atom, -SO-, or -SO ２ -, -CO-, -CO-O-, or -CH=N-O-. １ If is 0, -(CH ２ ) ０ - is a single bond, and Z is attached to the carbon atom of the purine ring. １ means that there is a direct bond.

[0027] R １１ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -NR １２ R １３ , -N ３ , -NO ２, -CN, -CH ２ -CO-O-R １４ or a 5- or 6-membered heterocyclic group containing a nitrogen atom. １２ and R １３ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R １４ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. １ are connected.

[0028] R １１ , R １２ , R １３ , and R １４ is an alkyl group having 1 to 6 carbon atoms, the alkyl group may be linear or branched. More specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a sec-pentyl group, an isopentyl group, an n-hexyl group, a sec-hexyl group, an isohexyl group, etc. are preferred, an alkyl group having 1 to 4 carbon atoms is more preferred, an alkyl group having 1 to 3 carbon atoms is even more preferred, and a methyl group or an ethyl group is even more preferred.

[0029] More specifically, the compound (1) includes a compound represented by any one of general formulas (1-1) to (1-15), and the compound (2) includes a compound represented by any one of general formulas (2-1) to (2-15).

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] In the general formula (1-1) and the general formula (2-1), R ２１ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -CH２ -COOH or amino group (-NH ２ ) As the alkyl group having 1 to 6 carbon atoms, R １１ The same groups as those listed in the above can be used.

[0037] In the general formula (1-2) and the general formula (2-2), R ２２ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an amino group. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0038] In the general formula (1-3) and the general formula (2-3), R ２３ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0039] In the general formula (1-4) and the general formula (2-4), R ２４ is an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0040] In the general formula (1-5) and the general formula (2-5), R ２５ is an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0041] In the general formula (1-6) and the general formula (2-6), R ２６ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0042] In the general formula (1-7) and the general formula (2-7), R ２７ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0043] In the general formula (1-8) and the general formula (2-8), R ２８is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a cyano group (—CN). Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0044] In the general formula (1-9) and the general formula (2-9), R ２９ is an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0045] In the general formula (1-10) and the general formula (2-10), R ３０ is an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0046] In the general formula (1-11) and the general formula (2-11), R ３１ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used.

[0047] In the general formula (1-12) and the general formula (2-12), R ３２ and R ３３ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in R can be used. ３２ and R ３３ are each independently preferably a hydrogen atom, a methyl group, or an ethyl group, and R ３２ and R ３３ are more preferably hydrogen atoms, methyl groups, or ethyl groups. ３２ is a hydrogen atom, and R ３３ It is also preferred that is a methyl group or an ethyl group.

[0048] In the general formula (1-13) and the general formula (2-13), R ３４ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -CH ２ -N ３ , cyano group, amino group, nitro group (-NO２ ), or an azido group (—N ３ ) As the alkyl group having 1 to 6 carbon atoms, R １１ The same groups as those listed in the above can be used.

[0049] In the general formula (1-14) and the general formula (2-14), R ３５ is an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include R １１ The same groups as those listed in the above can be used. ３５ may be the same or different groups. ３５ is preferably a hydrogen atom, a methyl group, or an ethyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0050] In general formula (1-15) and general formula (2-15), A is a 5- or 6-membered heterocyclo ring group containing a nitrogen atom. In the heterocyclo ring group, the nitrogen atom in the ring group is linked to a carbon atom of a purine ring via a methylene group. Examples of the heterocyclo ring group include monovalent groups obtained by removing the hydrogen atom bonded to the nitrogen atom from pyrrolidine, piperidine, morpholine, and thiomorpholine.

[0051] The compound (1) is preferably a compound represented by general formula (1-13), a compound represented by general formula (1-1), or a compound represented by general formula (1-11), and R ３４ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a cyano group, or a nitro group; ２１ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, or a compound in which R ３１ is more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0052] The compound (2) is preferably a compound represented by the general formula (2-13), a compound represented by the general formula (2-1), or a compound represented by the general formula (2-11), and R ３４is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a cyano group, or a nitro group; ２１ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, or a compound in which R ３１ is more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0053] The antiviral agent according to the present invention is particularly preferably one or more compounds selected from the group consisting of HUP1136 (tubercidin) (CAS No.: 69-33-0), HUP1108 (5-hydroxymethyltubercidin), HUP1069 (5-formyltubercidin oxime), HUP1077 (tubercidin N-oxide), HUP1078 (5-nitrotubercidin), and HUP1109 (5-cyanotubercidin, toyocamycin).

[0054]

[0055] HUP1108, HUP1069, HUP1077, HUP1078, and HUP1109 can be synthesized from HUP1136 by the method described in Non-Patent Document 2. HUP1108 can also be synthesized from HUP1136 by the method described in Non-Patent Document 3, and can also be synthesized from sangivamycin, a natural product, by the method described in Non-Patent Document 4.

[0056] In the antiviral agent according to the present invention, compound (1) and compound (2) may form a salt, and examples of the acid or base that forms the salt include mineral acids such as hydrochloric acid and sulfuric acid; organic acids such as acetic acid, succinic acid, and citric acid; alkali metals such as sodium and potassium; alkaline earth metals such as calcium and magnesium; etc. Compound (1) and compound (2) may also be in the form of a solvate such as a hydrate.

[0057] A derivative of compound (1) or a derivative of compound (2) may be used as the antiviral agent of the present invention. As the derivative of compound (1) or the derivative of compound (2), a derivative that is produced by undergoing enzymatic processing or the like in vivo to produce compound (1) or compound (2) is preferred. In the present invention, as the derivative of compound (1) or the derivative of compound (2) that can be used as an antiviral agent, a derivative obtained by, for example, prodrug formation carried out on pharmaceuticals containing nucleic acid compounds as active ingredients is more preferred. Specifically, in general formula (1) or general formula (2), a hydroxy group linked to the furan ring via a methylene group is replaced by a phosphate group (PO ４ － ), monophosphoramidite derivatives in which the hydroxy group is substituted with a monophosphoramidite group, and monophosphorothioate derivatives in which the hydroxy group is substituted with a monophosphorothioate group. The derivatives of compound (1) and compound (2) may form salts or may be in the form of solvates such as hydrates. The salts that can be used include those listed above.

[0058] Compound (1), a derivative of compound (1), compound (2), a derivative of compound (2), a salt of these compounds, or a solvate thereof (hereinafter, these may be collectively referred to as the "nucleic acid compound according to the present invention") has antiviral activity against viruses, particularly coronaviruses and flaviviruses, and is therefore useful as an active ingredient of a pharmaceutical composition used for the treatment or prevention of viral infections.

[0059] Coronaviruses include SARS-CoV, MERS-CoV, and SARS-CoV-2. There are various variants of SARS-CoV-2, including α strains (alpha strains) (B.1.1.7 lineage), β strains (beta strains) (B.1.351 lineage), γ strains (gamma strains) (P.1 lineage), δ strains (delta strains) (B.1.617.2 lineage), ο strains (omicron strains) (B.1.1.529), E484K strains (R.1 lineage), ε strains (epsilon strains) (B.1.427 / B.1.429 lineage), θ strains (theta strains) (P.3 lineage), κ strains (kappa strains) (B.1.617.1 lineage), and other variants. Flaviviruses, like coronaviruses, are enveloped viruses whose genes are positive-sense single-stranded RNA, and include dengue virus (DENV), which causes dengue fever (dengue hemorrhagic fever), Zika virus (ZIKV), which causes Zika fever (Zika virus infection), yellow fever virus (YFV), which causes yellow fever, West Nile virus (WNV), which causes West Nile fever (West Nile encephalitis), and Japanese encephalitis virus (JEV), which causes Japanese encephalitis. There are four types of DENV, types 1 to 4 (DENV1, DENV2, DENV3, and DENV4).

[0060] Like remdesivir, the nucleic acid compound according to the present invention inhibits RNA-dependent RNA polymerase (RdRp). Therefore, it has antiviral activity against viruses replicated by RdRp. Examples of such viruses include viruses that cause viral hepatitis, such as coronaviruses, flaviviruses, and hepacivirus C. The nucleic acid compound according to the present invention can be used to treat infectious diseases caused by viruses replicated by RdRp.

[0061] The nucleic acid compounds of the present invention are particularly useful as active ingredients in pharmaceutical compositions used to treat or prevent coronavirus infections, including COVID-19. Because the various SARS-CoV-2 mutant strains all require RdRp for replication, the nucleic acid compounds of the present invention have antiviral activity against all of these mutant strains. Furthermore, the nucleic acid compounds of the present invention are also very useful as active ingredients in pharmaceutical compositions used to treat or prevent flavivirus infections, including dengue fever, Zika fever, yellow fever, West Nile fever, and Japanese encephalitis. Because the nucleic acid compounds of the present invention are low-molecular-weight compounds, they are free from problems such as immunogenicity. Furthermore, because they can be administered orally and the route of administration is not particularly limited, they are particularly useful as active ingredients in pharmaceuticals for mammals, including humans.

[0062] Non-Patent Document 7 discusses the cellular uptake of GS-441524. The authors speculate that cellular uptake of GS-441524 is entirely dependent on adenosine transporters present on the cell surface, and that these transporters are reduced in hypoxic lung epithelial cells and certain cell lines, resulting in reduced cellular uptake of GS-441524. One major difference between GS-441524 and tubercidin derivatives, such as HUP1108, is that GS-441524 has a cyano group (—CN) attached to position 1, whereas HUP1108 does not. Therefore, this difference may be one of the reasons why the compounds of the present invention exhibit superior efficacy compared to GS-441524.

[0063] Therefore, the compounds of the present invention are believed to be taken up into cells via multiple mechanisms, thereby alleviating the problem of reduced uptake into hypoxic lung epithelial cells in which adenosine transporters are reduced, and are believed to have excellent antiviral activity.

[0064] When one or more nucleic acid compounds according to the present invention are incorporated into a pharmaceutical composition, they may be compounded with a pharmaceutically acceptable carrier as needed, and various dosage forms may be employed depending on the purpose of prevention or treatment. Examples of such dosage forms include oral preparations, injections, suppositories, ointments, patches, etc., with oral preparations being preferred. Each of these dosage forms can be prepared by a formulation method commonly known and commonly used by those skilled in the art.

[0065] Pharmaceutically acceptable carriers include excipients, binders, disintegrants, lubricants, and colorants for solid preparations, and solvents, solubilizers, suspending agents, isotonicity agents, buffers, and soothing agents for liquid preparations. Furthermore, formulation additives such as preservatives, antioxidants, colorants, sweeteners, and stabilizers can also be used as needed.

[0066] When preparing a solid oral preparation, an excipient, and if necessary, a binder, a disintegrant, a lubricant, a colorant, a flavoring agent, an odor masking agent, etc., are added to the nucleic acid compound of the present invention, and then tablets, coated tablets, granules, powders, capsules, etc. can be produced by conventional methods.

[0067] When preparing oral liquid preparations, flavoring agents, buffers, stabilizers, odorants, etc. can be added to the nucleic acid compound of the present invention to produce oral liquid preparations, syrups, elixirs, etc. using conventional methods.

[0068] When preparing an injection, a pH adjusting agent, a buffering agent, a stabilizer, an isotonic agent, a local anesthetic, etc. can be added to the nucleic acid compound of the present invention, and subcutaneous, intramuscular, and intravenous injections can be produced by conventional methods.

[0069] Suppositories can be prepared by adding pharmaceutical carriers known in the art, such as polyethylene glycol, lanolin, cocoa butter, and fatty acid triglycerides, to the nucleic acid compound of the present invention and then manufacturing them by conventional methods. Ointments can be prepared by blending bases, stabilizers, humectants, preservatives, and the like commonly used with the nucleic acid compound of the present invention as needed, and mixing and formulating them by conventional methods. Patches can be prepared by applying the ointment, cream, gel, paste, etc. to a conventional support by conventional methods.

[0070] The content of the nucleic acid compound of the present invention in each of the above-mentioned preparations varies depending on the patient's symptoms, dosage form, etc., but is generally about 0.001 to 1000 mg for oral preparations, about 0.001 to 500 mg for injections, and about 0.01 to 1000 mg for suppositories.

[0071] The daily dose of these preparations varies depending on the symptoms, body weight, age, sex, etc. of the patient and cannot be determined in general, but is usually about 0.005 to 5000 mg, preferably 0.01 to 1000 mg, per day for an adult (body weight 60 kg), and is preferably administered once a day or in divided doses about 2 to 3 times a day.

[0072] Furthermore, the dosage of the nucleic acid compound according to the present invention is not particularly limited, but is preferably less than 60 mg / kg, more preferably 10 mg / kg or more but less than 60 mg / kg, and even more preferably 15 to 40 mg / kg. For example, the dosage of the nucleic acid compound according to the present invention can be 15 to 30 mg / kg, or even 20 mg / kg. Furthermore, for example, less than 60 mg / kg of HUP1108 (5-hydroxymethyltubercidin) can be administered, and it is preferable to administer 20 mg / kg of HUP1108.

[0073] The animal to which the antiviral agent and pharmaceutical composition containing the nucleic acid compound according to the present invention as an active ingredient is administered is not particularly limited, and may be a human or a non-human animal. Non-human animals include mammals such as cows, pigs, horses, sheep, goats, monkeys, dogs, cats, rabbits, mice, rats, hamsters, and guinea pigs, and birds such as chickens, quails, and ducks.

[0074] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0075] <Coronavirus> Among the coronaviruses used in the following experiments, SARS-CoV-2 strain JPN / TY / WK-521 provided by the National Institute of Infectious Diseases and its mutant strains QK002 (α strain), TY8-612 (β strain), TY5-501 (γ strain), and TY11-927 (δ strain), all provided by the National Institute of Infectious Diseases, were used. Coronaviruses that commonly infect humans (HCoVs) were HCoV-229E (ATCC: VR-740) and HCoV-OC43 (ATCC: VR-1558) obtained from the ATCC.

[0076] <Flaviviruses> Of the flaviviruses used in the following experiments, the D1 / hu / PHL / 10-07 strain, D2 / hu / INDIA / 09-74 strain, D3 / hu / Thailand / 00-40 strain, and D4 / hu / Solomon / 08-11 strain were used for DENV1-4, respectively. The MR766 strain was used for ZIKV. The 17D-204 strain was used for YFV. The NY99 strain was used for WNV. The Beijing-1 strain was used for JEV.

[0077] <Cultured Cells> In the following experiments, MRC5 cells, a cultured cell line derived from human fetal lung, or Caco-2 cells, a cultured cell line derived from human colon cancer, were used for virus infection. For both cells, 2% FBS / MEM was used as the culture medium. 2% FBS / MEM was prepared by adding 2% FBS (fetal bovine serum: manufactured by Gibco) and L-glutamine (manufactured by Wako) to MEM (Minimum Essential Medium: manufactured by Nissui).

[0078] Example 1 Compounds from a nucleic acid compound library owned by the Center for Drug Discovery Science, Graduate School of Pharmaceutical Sciences, Hokkaido University, National University Corporation, were used as test samples to screen for compounds that have the effect of suppressing cell death in cells infected with human coronaviruses. HCoV-229E and HCoV-OC43 were used as human coronaviruses. As a result, six compounds from the compound library used, namely HUP1136, HUP1108, HUP1069, HUP1077, HUP1078, and HUP1109, were found to have antiviral activity.

[0079]

[0080] <Confirmation of cell death inhibitory effect> Six compounds evaluated to have antiviral activity were examined for their inhibitory effect on coronavirus-induced cell death. As positive controls, GS-5734 (remdesivir) and GS-441524 were also examined in the same manner.

[0081] First, cells treated with each compound were infected with the virus in each well of a 96-well plate. ２ Incubator (37°C, 5% CO ２ The cells were cultured for 3 days in a 96-well plate. After 3 days of culture, the 96-well plate was observed with the naked eye and under a microscope to confirm the cell morphology, the presence or absence of crystals, etc. Then, 20 μL of resazurin solution (a solution prepared by dissolving resazurin sodium salt (Sigma) in PBS to a concentration of 0.24 mg / mL) was dispensed into each well, and the cells were incubated in a CO ２ After 2 hours of incubation in an incubator, 20 μL of a reaction stop solution (virus inactivation solution: a solution of sodium dodecyl sulfate (SDS) dissolved in distilled water to a concentration of 7.5%) was dispensed into each well and mixed using a plate mixer. The fluorescence intensity of the 96-well plate was then measured at 531 nm (emission) / 590 nm (excitation) using a multiplate reader (device name: EnVision, manufactured by PerkinElmer).

[0082] Using statistical analysis software (product name: GraphPad Prism 8, manufactured by GraphPad Software), the 50% cell death inhibitory concentration (EC ５０ ) was calculated. ５０ and CC ５０ From the value of SI(CC ５０ / EC ５０ The calculation results are shown in Table 1.

[0083] [Agonist] vs response-Variable slope (four parametric) Y = Bottom + (X^HillSlope) * (Top - Bottom) / (X^HillSlope + EC50^HillSlope)

[0084] X: Concentration of test sample Y: Inhibition rate of infected cell death (cell viability) HillSlope: Slope of a series of curves Bottom (basal response) = 0 (0% inhibition rate of infected cell death) Top (maximum response) = 100 (100% inhibition rate of infected cell death)

[0085]

[0086] Example 2 The six compounds whose antiviral activity was confirmed in Example 1 were examined for their inhibitory effect on viral RNA replication against SARS-CoV-2. Caco-2 cells were used as cultured cells to be infected with the virus.

[0087] <Confirmation of the effect of inhibiting viral RNA replication> (1) Viral infection of cultured cells A culture medium consisting of 2% FBS / MEM was used to dilute the test samples (six compounds with confirmed antiviral activity), viruses, and cells. First, 100 μL of Caco-2 cell solution prepared to the appropriate cell number was dispensed into a 96-well plate, and the cells were then incubated in CO ２ Incubator (37°C, 5% CO ２) overnight. Next, a test sample previously diluted to an appropriate concentration with culture medium was added to each well of the 96-well plate containing Caco-2 cells so as to prepare a 3-fold serial dilution series (50 μL / well), and the mixture was mixed using a plate mixer. A virus solution previously diluted to an appropriate concentration with culture medium was dispensed at 50 μL / well into the 96-well plate containing the test sample. The 96-well plate was then mixed using a plate mixer, and the mixture was heated in a CO ２ Incubator (37°C, 5% CO ２ ) for 48 hours.

[0088] (2) RNA extraction and purification After 48 hours of culture, 150 μL of culture supernatant was collected from each well of the 96-well plate. The lysis buffer included in the RNA extraction kit (product name: PureLink Pro 96 Viral RNA / DNA Kit, manufactured by Thermo Fisher Scientific) was added to each well to inactivate the virus. Viral RNA was then purified according to the protocol included with the kit.

[0089] (3) Measurement of viral RNA Purified viral RNA and SARS-CoV-2 nucleocapsid region using a probe / primer set designed to perform real-time quantitative reverse transcription PCR (qRT-PCR). qRT-PCR was performed using a commercially available kit (product name: THUNDERBIRD Probe One-step qRT-PCR kit, manufactured by TOYOBO) and a real-time PCR system (product name: QuantStudio 7 Flex Real-Time PCR System, manufactured by Thermo Fisher Scientific).

[0090] The viral RNA copy number in each sample was calculated using the standard curve method. The standard curve was prepared by similarly performing qRT-PCR using a plasmid incorporating the base sequence containing the nucleocapsid region as a template (10 ９ ~10 ３ copies).

[0091] (4) Calculation of viral RNA replication inhibition rate The viral RNA replication inhibition rate (%) of the test sample at each concentration was calculated based on the viral RNA copy number in the test sample-free group. The amount of viral RNA (Log １０ The results of measuring the viral RNA replication inhibition rate ([viral RNA copy number derived from cells treated with the test sample] / [viral RNA copy number derived from cells in the test sample-free group]×100%) are shown in Figure 1, and the results of measuring the viral RNA replication inhibition rate ([viral RNA copy number derived from cells treated with the test sample] / [viral RNA copy number derived from cells in the test sample-free group]×100%) are shown in Figure 2.

[0092] Thereafter, the 90% viral RNA replication inhibitory concentration (EC ) was calculated using statistical analysis software (product name: GraphPad Prism 8, manufactured by GraphPad Software) based on the following formula: ９０ The calculation results are shown in Table 2.

[0093] [Agonist] vs response-Find ECanything EC50 = ECF / (F / (100 - F))^(1 / HillSlope) Y = Bottom + (Top - Bottom) / (1 + (EC50 / X)^HillSlope)

[0094] ECF: Concentration of test sample that results in a reaction value of F% between Bottom and Top. F: Desired inhibition rate (EC 90 In this case, F = 90) X: Concentration of the test sample Y: Inhibition rate of viral RNA replication HillSlope: Slope of the series of curves Bottom (basal response) = 0 (0% inhibition rate of viral RNA replication) Top (maximum response) = 100 (100% inhibition rate of viral RNA replication)

[0095]

[0096] As shown in Figures 1 and 2, in cells treated with the six compounds whose antiviral activity was confirmed in Example 1, the amount of virus released from infected cells tended to decrease and the rate of viral RNA replication inhibition increased in a compound dose-dependent manner, although this differed depending on the compound, confirming that these compounds have antiviral activity against SARS-CoV-2.

[0097] Microscopic observation during the test revealed that cells treated with HUP1109 exhibited strong cytotoxicity sufficient to cause cell death. Furthermore, HUP1078 (0.123 μM and above), HUP1136 (1.11 μM and above), and HUP1108 (10 μM) all exhibited mild cytotoxicity, but not sufficient to cause cell death. It was suggested that cells treated with HUP1078 and HUP1109 exhibited antiviral activity due to the cytotoxicity of these compounds. Meanwhile, the concentrations at which HUP1136 and HUP1108 demonstrated antiviral activity were lower than the concentrations at which they exhibited cytotoxicity. In particular, HUP1108 may have inhibited viral proliferation due to its cytotoxic effects at concentrations higher than 3.33 μM, but viral proliferation was also inhibited at concentrations lower than 3.33 μM, confirming that it has antiviral activity even at low concentrations that do not exhibit cytotoxicity. Of these six compounds, HUP1077 and HUP1108 in particular pose little risk of cytotoxicity and exhibit concentration-dependent inhibitory activity against viral RNA replication, and are therefore considered to be very useful as antiviral agents.

[0098] Example 3 A time-of-addition test was carried out to investigate the site of action of HUP1108 in the anti-SARS-CoV-2 activity. Caco-2 cells were used as cultured cells to be infected with the virus.

[0099] <Time-of-Addition Test> (1) Viral Infection of Cultured Cells A culture medium consisting of 2% FBS / MEM was used to dilute the test sample (HUP1108), virus, and cells. First, 300 μL of Caco-2 cell solution prepared to the appropriate cell number was dispensed into a 48-well plate at a rate of 1 / well. ２ Incubator (37°C, 5% CO２ After removing the culture supernatant from each well containing Caco-2 cells in the 48-well plate, a virus solution (150 μL / well) previously diluted to an appropriate concentration with culture medium was added, and then test samples (150 μL / well, final concentration: 1 μM) previously diluted with culture medium were added at the following three timings (Whole, Entry, and Post-entry). ２ Incubator (37°C, 5% CO ２ ) for a total of 24 hours.

[0100] Whole: The test sample is present throughout the entire viral infection process. The test sample is added at the same time as the virus solution is added, and the mixture is mixed with a plate mixer. ２ Incubator (37°C, 5% CO ２ After that, the culture supernatant was removed, the cells were washed with culture medium, and a new culture medium containing a test sample was added. ２ Incubator (37°C, 5% CO ２ ) for 24 hours.

[0101] Entry: The test sample is present only at the time of virus entry. The test sample is added at the same time as the virus solution is added, mixed with a plate mixer, and then cooled with CO ２ Incubator (37°C, 5% CO ２ After that, the culture supernatant was removed, and the cells were washed with culture medium. After that, a culture medium containing a new test sample was added, and the cells were incubated in CO ２ Incubator (37°C, 5% CO ２ After that, the culture supernatant was again removed, and the cells were washed with culture medium. After that, a culture medium not containing the test sample was added, and the cells were incubated in CO ２ Incubator (37°C, 5% CO ２ ) for 22 hours.

[0102] Post-entry: The test sample is present only after the virus has entered. When the virus is added, the test sample is not added, and CO ２ Incubator (37°C, 5% CO ２After that, the culture supernatant was removed, the cells were washed with culture medium, and a new culture medium (containing no test sample) was added. ２ Incubator (37°C, 5% CO ２ After that, the culture supernatant was again removed, and the cells were washed with culture medium. Then, a culture medium containing a test sample was added, and the cells were incubated in CO ２ Incubator (37°C, 5% CO ２ ) for 22 hours.

[0103] (2) RNA extraction and purification After 24 hours of culture, the culture supernatant was collected from each well of the 48-well plate and used for virus titer measurement. The cells in the wells were washed with PBS (phosphate buffered saline) (300 μL x 2), and the lysis buffer included with the RNA extraction kit (product name: PureLink RNA Mini Kit, manufactured by Thermo Fisher Scientific) was added to each well to lyse the cells. Total RNA was then purified according to the protocol included with the kit.

[0104] (3) Measurement of viral RNA qRT-PCR was performed using purified total RNA and a probe / primer set designed for the nucleocapsid region of SARS-CoV-2. qRT-PCR was performed in the same manner as in Example 2, except that ACTB was used as an endogenous control.

[0105] (4) Calculation of viral RNA replication inhibition rate Based on the Ct value of each sample obtained by qRT-PCR, the relative viral RNA amount was calculated using the ΔΔCt method, assuming that the viral RNA amount in the test sample-free group was 1, and the viral RNA replication inhibition rate was calculated. The calculation results for the relative viral RNA amount for each sample are shown in Figure 3. The graph shown in Figure 3 was created using statistical analysis software (product name: GraphPad Prism 8, manufactured by GraphPad Software).

[0106] (5) Measurement of virus titer The culture supernatant recovered in (2) above was diluted with culture medium to an appropriate concentration and added to VeroE6 / TMPRSS2 cells (100 μL / well) dispensed into a 96-well plate. The mixture was mixed using a plate mixer and then incubated in CO ２ Incubator (37°C, 5% CO ２ The cells were cultured at 100°C for 72 hours. After that, the cytopathic effect (CPE) due to the virus infection was observed, and the median tissue culture infectious dose (TCID ５０ ) was calculated. ５０ The logarithmic values ​​of are shown in Figure 4. The graph shown in Figure 4 was created using statistical analysis software (product name: GraphPad Prism 8, manufactured by GraphPad Software).

[0107] As shown in Figures 3 and 4, when HUP1108 was administered whole or post-entry, a decrease in the relative viral RNA amount and viral titer was observed. These results suggest that the anti-SARS-CoV-2 activity of HUP1108 acts on the replication process after viral entry.

[0108] Example 4 Six compounds that were evaluated to have antiviral activity in Example 1 were examined for their inhibitory effect on cell death caused by flavivirus infection.

[0109] <Evaluation of Cell Death Inhibitory Effect> (1) Cultured Cells In the following experiments, BHK-21 cells, a cultured cell line derived from Syrian hamster kidney, were used for virus infection. 2% FBS / MEM or 2% FBS / RPMI-1640 was used as the culture medium. Each culture medium was prepared by adding 2% FBS (fetal bovine serum: Gibco) and L-glutamine (Wako) to MEM (Minimum Essential Medium: Nissui) or RPMI-1640 (Gibco).

[0110] (2) Viral infection and MTT assay First, cells treated with each compound were infected with various viruses in each well of a 96-well plate. ２Incubator (37°C, 5% CO ２ ) for 4 days for DENV2, 5 days for DENV1, 3, and 4, and 3 days for ZIKV, YFV, WNV, and JEV. The cultured 96-well plates were observed with the naked eye and under a microscope to confirm cell morphology and the presence or absence of crystals. Next, 30 μL of MTT solution (a solution prepared by dissolving 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (Nacalai Tesque) in PBS to a concentration of 5 μg / mL) was added to each well, and the cells were incubated in a CO ２ The plates were cultured for 2 hours in an incubator. Then, 150 μL of the supernatant was removed from the plate without sucking up the cells, and 150 μL of cell lysis solution (virus inactivation solution: prepared by adding 50 mL of Triton X-100 and 4 mL of hydrochloric acid (12 N) to 500 mL of isopropanol) was added to each well and mixed using a plate mixer. The absorbance of the 96-well plate was then measured at two wavelengths, 570 nm and 630 nm, using an absorbance meter.

[0111] (3) EC ５０ Calculation of 50% cell death inhibitory concentration (EC ５０ The results are shown in Table 3.

[0112] [EC 50 ] = 10 Z Z = ([50% OD] - [Low OD]) / ([High OD] - [Low OD]) × {log (High conc.) - log (Low conc.)} + log (Low conc.) [50% OD] = {OD (cell control) - OD (virus control)} × 0.5 + OD (virus control)

[0113] OD: absorbance conc.: drug concentration OD (cell control): mean absorbance of control wells OD (virus control): mean absorbance of virus control wells

[0114] EC ５０ was calculated from two points A-High (High OD, High conc.) and B-Low (Low OD, Low conc.) that sandwich the 50% OD value on the absorbance vs. drug concentration curve.

[0115] The results are shown in Table 3. As shown in Table 3, of the six compounds, four compounds, HUP1136, HUP1108, HUP1069, and HUP1077, were found to have high antiviral activity against DENV1, DENV2, DENV3, DENV4, ZIKV, YFV, WNV, and JEV.

[0116] Furthermore, Non-Patent Document 5 reports the antiviral activity of GS-441524 against DENV2 (EC ５０ ) was 9.46 μM. This value is significantly higher than that of the compounds of the present invention, HUP1136, HUP1108, HUP1069, and HUP1077, and is particularly about 10 times higher than that of HUP1108 and about 40 times higher than that of HUP1136. Non-Patent Document 5 also reported that the antiviral activity (EC ５０ ) was reported to be 11 μM. This value is significantly higher than both HUP1136 and HUP1108, and is particularly about 40 times higher than HUP1108 and about 73 times higher than HUP1136. Therefore, it is clear that the antiviral activity of the compound of the present invention is significantly higher than that of GS-441524.

[0117]

[0118] Example 5 The inhibitory effect of HUP1108 on viral RNA replication against the SARS-CoV-2 WK-521 strain and various mutant strains (α, β, γ, and δ strains) was investigated using a method similar to that used in Example 2. However, when infecting cultured cells with the virus, a test sample previously diluted to an appropriate concentration with culture medium was added to each well of a 96-well plate containing Caco-2 cells so as to prepare a 2-fold serial dilution series (50 μL / well) rather than a 3-fold serial dilution series, and the mixture was mixed using a plate mixer.

[0119] As shown in Figure 5, a tendency for the amount of virus released from infected cells to decrease in a dose-dependent manner was observed, confirming that HUP1108 has antiviral activity against all five strains of SARS-CoV-2. From these results, it can be said that HUP1108 also has antiviral activity against other variants of SARS-CoV-2 (e.g., the Omicron strain).

[0120] Example 6 (1) In vivo mouse model (intrapulmonary viral load measurement model) SARS-CoV-2 (WK-521 strain) was inoculated intranasally into BALB / c mice, and the lung homogenate supernatant obtained 3 days after infection was inoculated into subsequent mice. This passage was repeated 10 times. Stably high viral titers were obtained from passage 3 (P3), but deaths occurred from P9 onward. Genetic analysis of the P10 virus was performed using next-generation sequencing (NGS). As a result, a Q498H mutation was confirmed in the spike protein region, which determines the infectivity of the virus. The effect of HUP1108 on inhibiting viral growth in the mouse lung was examined using a growth evaluation model using the virus (MA-P10 strain) adapted to this mouse. Five-week-old BALB / c mice were inoculated with the MA-P10 strain (2 × 10 ２ TCID ５０ The day after infection, lungs were collected from each mouse and the virus titer in the lungs was measured (five mice per group). The results showed that the virus load in the lungs of the group that received a single intramuscular dose of HUP1108 (20 mg / kg) 2 hours before infection was approximately 1.3 log lower than that of the group that received only the vehicle (Vehicle) (Fig. 6).

[0121] (2) In vivo mouse model (lethality model) Next, the lethality suppression effect of HUP1108 was examined using this MA-P10 strain-infected mouse model. BALB / c mice aged 30 to 50 weeks were infected with SARS-CoV-2 (MA-P10 strain) (2 × 10 ２ TCID ５０ Mice were inoculated intranasally with SARS-CoV-2 (100 mg / kg / mouse), and HUP1108 was administered intramuscularly (20 mg / kg) once 2 hours before infection and once daily from the day after infection until 4 days after infection for a total of 5 days. Survival rates were calculated (5 mice per group). The survival rate of mice in the HUP1108-administered group was 100%, while the survival rate of mice in the vehicle-administered group for 5 days was 40% (Figure 7). In other words, repeated administration of HUP1108 suppressed the lethal effect of SARS-CoV-2.

[0122] Non-Patent Document 6 reported that oral administration of GS-621763 at 60 mg / kg or more per day or oral administration of MPV (Molnupiravir) at 120 mg / kg or more per day to a SARS-CoV-2-MA10 model improved acute respiratory distress syndrome. In contrast, intramuscular administration of the compound of the present invention, HUP1108, at 20 mg / kg per day to a similar mouse model significantly reduced the amount of virus in the lungs and achieved a 100% survival rate. HUP1108 was also confirmed to be a compound that exhibited extremely high antiviral activity against SARS-CoV-2 even in vivo at low doses.

Claims

1. The following general formula (1) or (2): 【Chemistry 1】 [In the formula, R １ is -(CH ２ ) n １ -Z １ -R １１ or -CH-(-Z １ -R １１ ) ２ and n １ is 0 or 1; Z １ represents a single bond, an oxygen atom, -NH-, a sulfur atom, -SO-, or -SO ２ -, -CO-, -CO-O-, or -CH=N-O-; R １１ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -NR １２ R １３ , -N ３ , -NO ２ , -CN, -CH ２ -C-O-R １４ or a 5- or 6-membered heterocyclic group containing a nitrogen atom; R １２ and R １３ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R １４ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, The nitrogen atom in the heterocyclic group and Z １ are connected. or a derivative, a salt, or a solvate thereof.

2. The compound represented by the general formula (1) is represented by the following general formulas (1-1) to (1-15): 【Chemistry 2】 【Chemistry 3】 【Chemistry 4】 [In the formula, R ２１ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -CH ２ -COOH or an amino group; R ２２ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an amino group; R ２３ , R ２６ , R ２７ , R ３１ , R ３２ , and R ３３ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R ２４ , R ２５ , R ２９ , R ３０ , and R ３５ is an alkyl group having 1 to 6 carbon atoms; R ２８ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a cyano group; R ３４ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -CH ２ -N ３ , cyano, amino, nitro, or azide; A is a 5- or 6-membered heterocyclic group containing a nitrogen atom. The compound represented by the general formula (2) is selected from the group consisting of the following general formulas (2-1) to (2-15): 【Chemistry 5】 【Chemistry 6】 【Chemistry 7】 [In the formula, R ２１ ~R ３５ and A are the same as above. The antiviral agent of claim 1, selected from the group consisting of:

3. HUP1136, HUP1108, HUP1069, HUP1077, HUP1078, and HUP1109 【Chemistry 8】 The antiviral agent according to claim 1 or 2, comprising one or more compounds selected from the group consisting of:

4. An antiviral agent described in any one of claims 1 to 3, comprising HUP1108.

5. A pharmaceutical composition comprising the antiviral agent according to any one of claims 1 to 4.

6. 6. A pharmaceutical composition according to claim 5 for use in the treatment of infections caused by coronaviruses or flaviviruses.

7. The pharmaceutical composition described in claim 6, wherein the infectious disease is caused by COVID-19.

8. The pharmaceutical composition according to claim 6 or 7, wherein the infectious disease is caused by SARS-CoV-2.

9. The pharmaceutical composition according to claim 8, wherein the SARS-CoV-2 is at least one selected from the group consisting of WK-521 strain, α strain, β strain, γ strain, δ strain, and ο strain.

10. The pharmaceutical composition according to claim 6, wherein the flavivirus is at least one selected from the group consisting of dengue virus (DENV), Zika virus (ZIKV), yellow fever virus (YFV), West Nile virus (WNV) and Japanese encephalitis virus (JEV).

11. The pharmaceutical composition according to any one of claims 6 to 10, which is used together with an inhibitor of 3CL protease.

12. The pharmaceutical composition according to claim 11, wherein the 3CL protease inhibitor is at least one selected from the group consisting of PF-07304814 and S-217622.

13. A pharmaceutical composition described in any one of claims 6 to 12, formulated to be administered in an effective amount of less than 60 mg / kg.

14. A pharmaceutical composition described in any one of claims 6 to 13, formulated to be administered in an effective amount of 20 mg / kg.

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