Synthesis and evaluation of 9-aminoacridines with SARS-COV-2 antiviral activity

Abstract

The synthesis and characterization of a series of derivatives and analogs based on the 9-aminoacridine scaffold shared by antimalarial drugs quinacrine and pyronaridine are described. Also described is the structure-activity relationship of these compounds against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the coronavirus disease of 2019 (COVID-19). Several compounds displayed potent in vitro activity, with 50% inhibitory concentrations below 1 micromolar.

Description

[0001] DESCRIPTION

[0002] SYNTHESIS AND EVALUATION OF 9-AMINO ACRIDINES WITH SARS-COV-2 ANTIVIRAL ACTIVITY CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and benefit of U.S. Provisional Patent Application Serial No. 63 / 542,676, filed October 5, 2023, which is herein incorporated by reference in its entirety. GOVERNMENT SUPPORT

[0003] This invention was made with government support under Grant Numbers R44GM 122196-02 Al and 1R43AT010585-01 awarded by the National Institutes of Health. The government has certain rights in the invention.

[0004] TECHNICAL FIELD The presently disclosed subject matter relates to 9-aminoaciridine compounds and analogs thereof. The presently disclosed subject matter further relates to the antiviral activity (e.g., anti-coronavirus activity) of the 9-aminoacridine compounds and analogs.

[0005] ABBREVIATIONS ACE2 = angiotensin converting enzyme 2

[0006] CCso = concentration of cytotoxicity 50%

[0007] COVID-19 = coronavirus disease of 2019

[0008] DMEM = Dulbecco’s modified eagle medium

[0009] DMF = N,N-dimethylformamide

[0010] DMSO = dimethyl sulfoxide

[0011] Et = ethyl

[0012] FCS = fetal calf serum

[0013] FDA = Food and Drug Administration

[0014] GFP = green fluorescent protein

[0015] IC50 = inhibitory concentration 50%

[0016] Me = methyl

[0017] MOI = multiplicity of infection

[0018] Mpro= coronavirus main protease PBS = phosphate buffered saline

[0019] PFA = paraformaldehyde

[0020] PLpro= papain-like protease

[0021] PS = phosphatidylserine rt = room temperature

[0022] SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2

[0023] SI = selectivity index

[0024] BACKGROUND

[0025] While as of June 2023 the coronavirus disease of 2019 (COVID-19) pandemic has ended based on the WHO recommendation, there are very few small molecule treatments developed for this disease1,2and preparation for future outbreaks of this virus or related viruses is still of great importance. COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The pandemic caused unprecedented economic and social hardships, affecting over 767 million people and causing over 6.9 million deaths worldwide.3Infection with SARS-CoV-2 leads to a broad range of clinical symptoms including respiratory distress, cough, immune system disruption, and loss of smell and taste4,5. While the development of various COVID-19 vaccines has been successful at preventing infection and decreasing symptom severity,6there is a recognized need for complementary antiviral agents which have direct activity against circulating SARS-CoV-2 strains. Remdesivir7,8is the only FDA-approved antiviral drug for the treatment of COVID-19, while molnupiravir and paxlovid both obtained emergency use authorizations in 2021 for treating infections with this virus in the USA9, and the latter obtained full approval from the FDA recently.

[0026] Accordingly, there is an ongoing need for additional small molecule compounds that can treat viral infections, such as coronavirus infections, including SARS-CoV-2 infections and the disease caused by SARS-CoV-2, i.e., COVID-19.

[0027] SUMMARY

[0028] This summary lists several embodiments of the presently disclosed subject matter, and in many cases lists variations and permutations of these embodiments. This summary is merely exemplary of the numerous and varied embodiments. Mention of one or more representative features of a given embodiment is likewise exemplary. Such an embodiment can typically exist with or without the feature(s) mentioned; likewise, those features can be applied to other embodiments of the presently disclosed subject matter, whether listed in this summary or not. To avoid excessive repetition, this summary does not list or suggest all possible combinations of such features.

[0029] In some embodiments, the presently disclosed subject matter provides a compound having a structure of Formula (I) or (II): wherein: X is CH or N; Y is CH or N; Ri is H, halo, or perhaloalkyl; R2 is H or halo; R3 is halo or alkoxy; R4 is -NH-alkyl, -NH-substituted alkyl, or -N-heterocycle; R7 is H or - CH2N(R9)2; RS is -CH2N(R9)2; and each R9 is alkyl or wherein two R9 together are alkylene and together with the nitrogen atom to which they are attached form a nitrogen-containing heterocycle; or a pharmaceutically acceptable salt thereof; and wherein when the compound has a structure of Formula (I) and X and Y are each CH, Ri is H, and R2 is Cl, Rais not methoxy; and wherein when the compound has a structure of Formula (II) and X is CH, Ri is H, and R2 is Cl, R3 is not methoxy.

[0030] In some embodiments, the compound has a structure of Formula (I). In some embodiments, X is CH, optionally wherein X is CH and Y is N. In some embodiments, Ri and R.3 are each Cl. In some embodiments, Ri is halo or perfluoroalkyl, optionally Cl or CF3 and R2 is H. In some embodiments, R4 is -NHCH(Rs)-L-N(R6)2 or -NHCH(Rs)-L-C-(NHR6)2, wherein Rs is alkyl, optionally methyl, L is alkylene, optionally propylene, and Re is alkyl, optionally ethyl or methyl. In some embodiments, the compound is selected from the group comprising: or a pharmaceutically acceptable salt thereof.

[0031] In some embodiments, the compound has a structure of Formula (II). In some embodiments, X is N and Y is CH. In some embodiments, Ri is halo or perfluoroalkyl, optionally wherein Ri is Cl, F, or CF3. In some embodiments, R3 is halo, optionally Cl. In some embodiments, Rs is -CHN(R9)2, wherein the two R9 together are butylene, optionally wherein R7 is H or -CHN(R9)2, wherein the two R9 together are butylene. In some embodiments, the compound is selected from the group comprising:

[0032] or a pharmaceutically acceptable salt thereof.

[0033] In some embodiments, the presently disclosed subject matter provides a pharmaceutical composition comprising a compound having a structure of Formula (I) or (II) and a pharmaceutically acceptable carrier.

[0034] In some embodiments, the presently disclosed subject matter provides a method of treating a viral infection or a disease caused by a viral infection in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound of any having a structure of Formula (I) or (II) or a pharmaceutical composition thereof. In some embodiments, the viral infection is a coronavirus infection. In some embodiments, the coronavirus infection is an infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In some embodiments, the compound has a 50% inhibitory concentration (ICso) against SARS-CoV-2 that is less than about 2.0 micromolar (pM), optionally less than about 1.0 pM. In some embodiments, the compound has a 50% cytotoxicity concentration (CCso) that is greater than about 4.0 pM. In some embodiments, the compound has a selectivity index (SI) of about 10 or more.

[0035] In some embodiments, the compound is selected from the group comprising: or a pharmaceutically acceptable salt thereof.

[0036] In some embodiments, the presently disclosed subject matter provides the use of a compound having a structure of Formula (I) or (II) in the preparation of a medicament for treating a viral infection or a disease caused by a viral infection, optionally wherein the viral infection is a coronavirus infection, further optionally wherein the coronavirus infection is a SARS-CoV-2 infection. Accordingly, it is an object of the presently disclosed subject matter to provide compounds of Formulas (I) and (II), as well as related pharmaceutical compositions, uses, and methods of treating viral infections, such as coronavirus infections. An object of the presently disclosed subject matter having been stated hereinabove, and which is achieved in whole or in part by the presently disclosed subject matter, other objects will become evident as the description proceeds hereinbelow.

[0037] DETAILED DESCRIPTION

[0038] There have been relatively few small molecules described with direct activity against SARS-CoV-2. The presently disclosed subject matter provides a study of the structure-activity relationship of the 9-aminoacridine scaffold against SARS-CoV-2 using traditional medicinal chemistry to identify promising new analogs with activity against SARS-CoV-2. More particularly, the presently disclosed subject matter identifies several novel 9-aminoacridine compounds or analogs thereof possessing potent in vitro activity in U2-OS ACE2 GFP 1-10 and 1-11 (IC50 < 1.0 «M) as well as moderate cytotoxicity (CCso > 4.0 / / M). For example, the compound referred to herein as 12126190 displayed the most potent activity as well as the best selectivity index (IC50 < 0.42 «M, CC50 > 4.41 «M, SI > 10).

[0039] The presently disclosed subject matter will now be described more fully. The presently disclosed subject matter can, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein below and in the accompanying Examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the embodiments to those skilled in the art.

[0040] All references listed herein, including but not limited to all patents, patent applications and publications thereof, and scientific journal articles, are incorporated herein by reference in their entireties to the extent that they supplement, explain, provide a background for, or teach methodology, techniques, and / or compositions employed herein.

[0041] I. DEFINITIONS

[0042] While the following terms are believed to be well understood by one of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the presently disclosed subject matter.

[0043] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs.

[0044] Following long-standing patent law convention, the terms “a”, “an”, and “the” refer to “one or more” when used in this application, including the claims. The term “and / or” when used in describing two or more items or conditions, refers to situations where all named items or conditions are present or applicable, or to situations wherein only one (or less than all) of the items or conditions is present or applicable.

[0045] The use of the term “or” in the claims is used to mean “and / or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and / or.” As used herein “another” can mean at least a second or more.

[0046] The term “comprising”, which is synonymous with “including,” “containing,” or “characterized by” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. “Comprising” is a term of art used in claim language which means that the named elements are essential, but other elements can be added and still form a construct within the scope of the claim.

[0047] As used herein, the phrase “consisting of’ excludes any element, step, or ingredient not specified in the claim. When the phrase “consists of’ appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

[0048] As used herein, the phrase “consisting essentially of’ limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel character! stic(s) of the claimed subject matter.

[0049] With respect to the terms “comprising”, “consisting of’, and “consisting essentially of’, where one of these three terms is used herein, the presently disclosed and claimed subject matter can include the use of either of the other two terms.

[0050] Unless otherwise indicated, all numbers expressing quantities of time, concentration, dosage and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.

[0051] As used herein, the term “about”, when referring to a value is meant to encompass variations of in one example ±20% or ±10%, in another example ±5%, in another example ±1%, and in still another example ±0.1% from the specified amount, as such variations are appropriate to perform the disclosed methods.

[0052] As used herein the term “alkyl” refers to C1-20 inclusive, linear (z.e., "straight-chain"), branched, or cyclic, saturated or at least partially and in some cases fully unsaturated (z.e., alkenyl and alkynyl) hydrocarbon chains, including for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, octyl, ethenyl, propenyl, butenyl, pentenyl, hexenyl, octenyl, butadienyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, and allenyl groups. "Branched" refers to an alkyl group in which a lower alkyl group, such as methyl, ethyl or propyl, is attached to a linear alkyl chain. "Lower alkyl" refers to an alkyl group having 1 to about 8 carbon atoms (z.e., a Ci-8 alkyl), e.g., 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms; 1 to about 6 carbon atoms (i.e., a Ci-6 alkyl), or 1 to 5 carbon atoms (i.e., a C1-5 alkyl). "Higher alkyl" refers to an alkyl group having about 10 to about 20 carbon atoms, e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms. In some embodiments, "alkyl" refers, in particular, to C1-8 straight-chain alkyls. In some embodiments, “alkyl” refers, in particular, to C1-8 branched-chain alkyls. In some embodiments, “alkyl” refers, in particular to C1-6 or C1-5 straight-chain and / or branched-chain alkyls (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl.)

[0053] Alkyl groups can optionally be substituted (a “substituted alkyl”) with one or more alkyl group substituents, which can be the same or different. The term "alkyl group substituent" includes but is not limited to alkyl, substituted alkyl, halo, arylamino, acyl, hydroxyl, aryloxyl, alkoxyl, alkylthio, arylthio, aralkyloxyl, aralkylthio, carboxyl, alkoxycarbonyl, oxo, and cycloalkyl. There can be optionally inserted along the alkyl chain one or more oxygen, sulfur or substituted or unsubstituted nitrogen atoms, wherein the nitrogen substituent is hydrogen, lower alkyl (also referred to herein as “alkylaminoalkyl”), or aryl.

[0054] Thus, as used herein, the term "substituted alkyl" includes alkyl groups, as defined herein, in which one or more atoms or functional groups of the alkyl group are replaced with another atom or functional group, including for example, alkyl, substituted alkyl, halogen, aryl, substituted aryl, alkoxyl, hydroxyl, nitro, amino, alkylamino, dialkylamino, sulfate, and mercapto.

[0055] “Cyclic” and "cycloalkyl" refer to a non-aromatic mono- or multicyclic ring system of about 4 to about 10 carbon atoms. The cycloalkyl group can be optionally partially unsaturated. The cycloalkyl group can be also optionally substituted with an alkyl group substituent as defined herein, oxo and / or alkylene. There can be optionally inserted along the cyclic alkyl chain one or more oxygen, sulfur or substituted or unsubstituted nitrogen atoms, wherein the nitrogen substituent is hydrogen, lower alkyl, or aryl, thus providing a heterocyclic group. Representative monocyclic cycloalkyl rings include cyclopropyl, cyclopentyl, cyclohexyl and cycloheptyl. Representative multicyclic cycloalkyl rings include adamantyl, octahydronaphthyl, decalin, camphor, camphane, and noradamantyl. Representative nitrogen- containing heterocyclic groups include, but are not limited to, aziridine, piperidine, pyrroline, pyrrolidine, thiomorpholine, morpholine, azocane, and azepane.

[0056] "Alkoxyl" and “alkoxy” refer to an alkyl-O— group wherein alkyl is as previously described. The term "alkoxyl" as used herein can refer to C1-20 inclusive, linear, branched, or cyclic, saturated or unsaturated oxo-hydrocarbon chains, including for example methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy, and pentoxy.

[0057] The term "aryl" is used herein to refer to an aromatic substituent that can be a single aromatic ring, or multiple aromatic rings that are fused together, linked covalently, or linked to a common group, such as, but not limited to, a methylene or ethylene moiety. The common linking group also can be a carbonyl, as in benzophenone, or oxygen, as in diphenylether, or nitrogen, as in diphenylamine. The term "aryl" specifically encompasses heterocyclic aromatic compounds. The aromatic ring(s) can comprise phenyl, naphthyl, biphenyl, diphenylether, diphenylamine and benzophenone, among others. In particular embodiments, the term “aryl” means a cyclic aromatic comprising about 5 to about 10 carbon atoms, e.g., 5, 6, 7, 8, 9, or 10 carbon atoms, and including 5- and 6-membered hydrocarbon and heterocyclic aromatic rings.

[0058] The aryl group can be optionally substituted (a “substituted aryl”) with one or more aryl group substituents, which can be the same or different, wherein “aryl group substituent” includes alkyl, substituted alkyl, aryl, substituted aryl, aralkyl, hydroxyl, alkoxyl, aryloxyl, aralkyloxyl, carboxyl, acyl, halo, nitro, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, acyloxyl, acylamino, aroylamino, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl, arylthio, alkylthio, alkylene, and -NR'R", wherein R' and R" can each be independently hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, and aralkyl.

[0059] Thus, as used herein, the term "substituted aryl" includes aryl groups, as defined herein, in which one or more atoms or functional groups of the aryl group are replaced with another atom or functional group, including for example, alkyl, substituted alkyl, halogen, aryl, substituted aryl, alkoxyl, hydroxyl, nitro, amino, alkylamino, dialkylamino, sulfate, and mercapto.

[0060] Specific examples of aryl groups include, but are not limited to, cyclopentadienyl, phenyl, furan, thiophene, pyrrole, pyran, pyridine, imidazole, benzimidazole, isothiazole, isoxazole, pyrazole, pyrazine, triazine, pyrimidine, quinoline, isoquinoline, indole, carbazole, and the like.

[0061] “Heteroaryl” as used herein refers to an aryl group that contains one or more non-carbon atoms (e.g., O, N, S, Se, etc) in the backbone of a ring structure. Nitrogen-containing heteroaryl moieties include, but are not limited to, pyridine, imidazole, benzimidazole, pyrazole, pyrazine, triazine, pyrimidine, and the like.

[0062] “Aralkyl” refers to an -alkyl-aryl group, optionally wherein the alkyl and / or aryl moiety is substituted. Exemplary aralkyl groups include, but are not limited to, benzyl and ethylphenyl.

[0063] "Alkylene" refers to a straight or branched bivalent aliphatic hydrocarbon group having from 1 to about 20 carbon atoms, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms. The alkylene group can be straight, branched or cyclic. The alkylene group also can be optionally unsaturated and / or substituted with one or more "alkyl group substituents." There can be optionally inserted along the alkylene group one or more oxygen, sulfur or substituted or unsubstituted nitrogen atoms (also referred to herein as “alkylaminoalkyl”), wherein the nitrogen substituent is alkyl as previously described. Exemplary alkylene groups include methylene (-CH2-); ethylene (-CH2-CH2-); propylene (- (CH2)3-); cyclohexylene (-C6HIO-); -CH=CH— CH=CH-; -CH=CH-CH2-; -(CH2)q-N(R)- (CH2)I— , wherein each of q and r is independently an integer from 0 to about 20, e.g., 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, and R is hydrogen or lower alkyl; methylenedioxyl (-O-CH2-O-); and ethylenedi oxy 1 (-O-(CH2)2-O-). An alkylene group can have about 2 to about 3 carbon atoms and can further have 6-20 carbons.

[0064] The term “arylene” refers to a bivalent aromatic group, e.g., a bivalent phenyl or napthyl group. The arylene group can optionally be substituted with one or more aryl group substituents and / or include one or more heteroatoms.

[0065] The term “aralkylene” refers to a bivalent group that includes both aromatic and nonaromatic groups.

[0066] The term “amino” refers to the group -N(R)2 wherein each R is independently H, alkyl, substituted alkyl, aryl, substituted aryl, aralkyl, or substituted aralkyl. The terms “aminoalkyl” and “alkylamino” can refer to the group -N(R)2 wherein each R is H, alkyl or substituted alkyl, and wherein at least one R is alkyl or substituted alkyl. “Aralkylamine” can refer to the group -N(R)2wherein each R is H, aralkyl, or substituted alkyl and wherein at least one R is aralkyl or substituted aralkyl, e.g., aminobenyzl. “Dialkylamino” refers to an alkylamino group where both R are alkyl or substituted alkyl.

[0067] As use herein, the terms “administration of’ and / or “administering” a compound can be understood to refer to providing a compound of the presently disclosed subject matter to a subject in need of treatment. As used herein “administering” includes administration of a compound or compounds by any number of routes and modes including, but not limited to, oral, buccal, intravenous, intramuscular, intra-arterial, intramedullary, intrathecal, intraventricular, transdermal, subcutaneous, intraperitoneal, intranasal, enteral, topical, sublingual, vaginal, ophthalmic, pulmonary, vaginal, and rectal approaches.

[0068] As used herein, the term “pharmaceutically acceptable carrier” means a composition with which an appropriate compound can be combined and which, following the combination, can be used to administer the appropriate compound to a subject.

[0069] As used herein, the term “pharmaceutically acceptable” ester or salt means an ester or salt form of the active ingredient which is compatible with any other ingredients of the pharmaceutical composition, which is not deleterious to the subject to which the composition is to be administered.

[0070] As used herein, an “effective amount” or “therapeutically effective amount” refers to an amount of a compound or composition sufficient to produce a selected and / or detectable effect, such as but not limited to alleviating symptoms of a condition, disease, or disorder. In the context of administering compounds in the form of a combination, such as multiple compounds, the amount of each compound, when administered in combination with one or more other compounds, can be different from when that compound is administered alone. Thus, an effective amount of a combination of compounds refers collectively to the combination as a whole, although the actual amounts of each compound can vary. The term “more effective” means that the selected effect occurs to a greater extent by one treatment relative to the second treatment to which it is being compared.

[0071] The term “prevent” as used herein means to stop something from happening, or taking advance measures against something possible or probable from happening. In the context of medicine, “prevention” generally refers to action taken to decrease the chance of getting a disease or condition. It is noted that “prevention” need not be absolute, and thus can occur as a matter of degree.

[0072] The terms “treatment” and “treating” as used herein refer to both therapeutic treatment and prophylactic or preventative measures, wherein the object is to prevent or slow down (lessen) the targeted pathologic condition, prevent the pathologic condition, pursue or obtain beneficial results, and / or lower the chances of the individual developing a condition, disease, or disorder, even if the treatment is ultimately unsuccessful. Those in need of treatment include those already with the condition (e.g., those diagnosed with the condition or already experiencing symptoms of the conditions) as well as those prone to have or predisposed to having a condition, disease, or disorder, or those in whom the condition is to be prevented. Code numbers used herein to refer to particular compounds can be used to refer to the compound as well as any salts thereof. For example, 12126136 or 9a can be used here to refer to the compound having the structure: or to a salt thereof, e.g., to the HC1 salt thereof.

[0073] II. GENERAL CONSIDERATIONS

[0074] Current treatment strategies for SARS-CoV-2 pneumonia involve either prevention of viral attachment to the host cell or disruption of viral replication.1SARS-CoV-2 enters the host cell via a spike protein attachment to the host angiotensin converting enzyme 2 (ACE2) receptor.10After entry, viral RNA is translated by the host ribosome to generate two polyproteins, ppi a and pplab. The virus encodes two cysteine proteases, papain-like protease (PLpro) and the coronavirus main protease (Mpro), which cleave ppi a and pplab yielding nonstructural proteins which form complexes with the host membrane.11These proteases are essential for viral replication, making them attractive targets for antiviral therapeutics.12

[0075] A hot topic in the identification for antiviral drug candidates is the repurposing of existing drugs for new targets.1For example, remdesivir was originally developed for the treatment of hepatitis C and was later repositioned for COVID-19.13It was recently described that an antimalarial agent, pyronaridine, displays activity against a number of viruses including SARS-CoV-2.14'16The chemical structure of pyronaridine is shown below in Scheme 1, below. In subsequent studies, pyronaridine was shown to reduce viral load in the lungs of SARS-CoV- 2-infected mice.17Without being bound to any one theory, the antiviral effect of pyronaridine is believed to be most likely based on inhibition of replication, because it was found to selectively inhibit SARS-CoV-2 PLproactivity in vitro11Another antimalarial drug popular outside of the U.S., quinacrine, which has similar structural motifs, also displays similar in vitro activity against SARS-CoV-2.18,19’20The chemical structure of quinacrine is also shown below in Scheme 1.

[0076]

[0077] Scheme 1. Chemical Structures of Pyronaridine and Quinacrine.

[0078] III. 9-AMINOACRIDINE COMPOUNDS OF FORMULAS (I) AND (II)

[0079] As shown in Scheme 1, above, the chemical structures of antimalarial drugs pyronaridine and quinacrine each include a fused three-ring aromatic scaffold, i.e., 9- aminoacridine or an analog thereof that includes an additional heteroatom in one of the rings. Each also include an amino substituent on the central ring. The chemical structure and atom numbering system of 9-aminoacridine is shown in Scheme 2, below. The presently disclosed subject matter describes the structure-activity relationships of the 9-aminoacridine scaffold against SARS-CoV-2. Thus, in some embodiments, the presently disclosed subject matter relates to 9-aminoacridine derivatives or analogs thereof, i.e., compounds that include a 9- aminoacridine scaffold or an analog thereof. By “analog” is meant herein an acridine scaffold where at least one of the carbon atoms in one or both of the outer rings of the fused three-ring scaffold is replaced by a heteroatom (e.g., N, O, S, etc.) and / or where the nitrogen atom of the central ring is replaced by another heteroatom or CH. The presently disclosed derivatives and analogs can also include one or more substituents on a carbon atom of the fused ring structure (i.e., carbons 1, 2, 3, 4, 5, 6, 7, and or 8) and / or a substituent on the amino group (i.e., replacing one of the hydrogen atoms of the -NH2 group).

[0080] Scheme 2. Chemical Structure and Atom Numbering of 9- Aminoacridine Scaffold. In some embodiments, the 9-aminoacridine derivative or analog thereof includes 1, 2, or 3 nitrogen atoms in the backbone of the three-ring fused scaffold. In some embodiments, at least one ring nitrogen atom is at position 10 (i.e., as in the scaffold in Scheme 2). In some embodiments, at least one ring nitrogen atom is at position 8 or 4.

[0081] In some embodiments, the 9-aminoacridine derivative or analog thereof includes at least one substituent replacing a hydrogen atom of the amino group and 1 or 2 additional substituents on a ring carbon atom. In some embodiments, the additional substituents are attached to carbons 2, 3, 7, and / or 8. In some embodiments, the additional substituents are attached to carbons 7 and 2 or to carbons 7 and 3.

[0082] In some embodiments, the presently disclosed subject matter provides a compound having a structure of one of Formulas (I) or (II): wherein: X is CH or N; Y is CH or N; Ri is H, halo (e.g., Cl or F), or perhaloalkyl (e.g., CF3); R2 is H or halo (e.g., Cl); R3 is halo (e.g., Cl) or alkoxy (e.g., methoxy or another C1-5 alkoxy); R4 is -NH-alkyl, -NH- substituted alkyl, or -N-heterocycle (e.g., morpholine); R7 is H or - CH2N(R9)2; R8 is -CH2N(R9)2; and each R9 is alkyl (e.g., methyl or ethyl) or wherein two R9 together are alkylene (e.g., butylene) and together with the nitrogen atom to which they are attached form a nitrogen-containing heterocycle; or a pharmaceutically acceptable salt thereof. In some embodiments, when the compound has a structure of Formula (I) and when X and Y are each CH, R1 is H, and R2 is Cl, R3 is not methoxy. In some embodiments, when the compound has a structure of Formula (II) and when X is CH, R1 is H, and R2 is Cl, R3 is not methoxy. Thus, in some embodiments, the compound is other than, for example, pyronaridine or quinacrine. In some embodiments, when R2is Cl, R3is not alkoxy. In some embodiments, when R2 is Cl, R3 is not methoxy. In some embodiments, the compound has a structure of Formula (I): wherein X, Y, R1, R2, R3, and R4 are as defined above (i.e., X is CH or N; Y is CH or N; R1 is H, halo, or perhaloalkyl; R2is H or halo; R3is halo or alkoxy; R4is -NH-alkyl, -NH-substituted alkyl, or -N-heterocycle) or a pharmaceutically acceptable salt thereof. In some embodiments, when X and Y are each CH, R1 is H, and R2 is Cl, R3 is not methoxy. In some embodiments, X is CH. In some embodiments, Y is N. In some embodiments, Y is CH. In some embodiments, both X and Y are CH. In some embodiments, X is CH and Y is N. In some embodiments, X is N and Y is CH. In some embodiments, R2is H. In some embodiments, R1is H, halo, or perfluoralkyl (e.g., a C1-5perfluoroalkyl). In some embodiments, R1 is halo or perfluoroalkyl. In some embodiments, R1 is Cl, F, or CF3. In some embodiments, R1 is Cl or CF3. In some embodiments, R1 is F or CF3. In some embodiments, R1is halo or perfluoroalkyl (e.g., Cl or CF3) and R2is H. In some embodiments, R3 is alkoxy (e.g., C1-5 alkoxy) or halo. In some embodiments, R3 is methoxy or chloro. In some embodiments, R1and R3are each halo. In some embodiments, R1and R3are each Cl. In some embodiments, R2and R3are each Cl. In some embodiments, R4 is NH-substituted alkyl. In some embodiments, R4 is - NHCH(R5)-L-N(R6)2or -NHCH(R5)-L-C-(NHR6)2, wherein R5is alkyl (e.g., C1-5alkyl), L is alkylene (e.g., C1-5alkylene), and R6is alkyl (e.g., C1-5alkyl). In some embodiments, R5is methyl. In some embodiments, L is propylene. In some embodiments, R6 is ethyl or methyl. In some embodiments, R6 is ethyl. In some embodiments, the compound of Formula (I) is selected from the group including, but not limited to, N4-(2-Chloro-7-methoxyacridin-9-yl)-N1,N1-diethylpentane-1,4- diamine (also referred to herein as 12126136 or 9a), having the structure: , N1,N1-Diethyl-N4-(2-methoxy-7-(trifluoromethyl)acridin-9-yl)pentane-1,4-diamine (also referred to herein as 12126142 or 9b), having the structure: , N4-(2,7-Dichloroacridin-9-yl)-N1,N1-diethylpentane-1,4-diamine (also referred to herein as 12126190 or 9c), having the structure: N4-(7-chloro-2-methoxybenzo[b][1,5]naphthyridin-10-yl)-N1,N1-diethylpentane-1,4-diamine (also referred to herein as 12226050 or 9d), having the structure: ,or a pharmaceutically acceptable salt thereof (e.g., a HCl salt). In some embodiments, the compound has a structure of Formula (II):

[0083] wherein X, Y, R1, R2, R3, and R4are as defined above (i.e., X is CH or N; Y is CH or N; R1is H, halo, or perhaloalkyl; R2is H or halo; R3is halo or alkoxy; R7is H or -CH2N(R9)2; R8is - CH2N(R9)2; and each R9 is alkyl or wherein two R9 together are alkylene and together with the nitrogen atom to which they are attached form a nitrogen-containing heterocycle) or a pharmaceutically acceptable salt thereof. In some embodiments, when X is CH, R1is H, and R2 is Cl, R3 is not methoxy. In some embodiments, Y is CH. In some embodiments, X is N and Y is CH. In some embodiments, X and Y are each CH. In some embodiments, X is CH and Y is N. In some embodiments, R2 is H. In some embodiments, R1 is halo or perfluoroalkyl, optionally wherein R1 is Cl, F, or CF3. In some embodiments, R1is F or CF3. In some embodiments, R3 is halo. In some embodiments, R3 is Cl. In some embodiments, R3 is alkoxy. In some embodiments, R3 is methoxy. In some embodiments, R8is -CHN(R9)2where the two R9together are alkylene. In some embodiments, the two R9together are butylene (-CH2CH2CH2CH2-) or pentylene (- CH2CH2CH2CH2CH2-). In some embodiments, the two R9 together are butylene, In some embodiments, R7 is H or -CHN(R9)2, where the two R9 together are alkylene. In some embodiments, the two R9together are butylene or pentylene. In some embodiments, the two R9 together are butylene. In some embodiments, the compound of Formula (II) is selected from the group including, but not limited to, 4-((2-Chloro-7-methoxyacridin-9-yl)amino)-2-(pyrrolidin-1- ylmethyl)phenol (also referred to herein as 12126134 or 8a), having the structure: , 4-((2-Methoxy-7-(trifluoromethyl)acridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12126135 or 8b), having the structure: , 4-((2-Fluoro-7-methoxyacridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12126140 or 8c), having the structure: , 4-((2,7-Dichloroacridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12126191 or 8d), having the structure: , 4-((2,6-Dichloroacridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12226052 or 8e), having the structure: , 4-((7-Methoxybenzo[b]-1,8-naphthyridin-5-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12226053 or 8f), having the structure: , 4-((2-Chloro-7-methoxyacridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12126131 or 7a), having the structure: , 4-((7-Methoxybenzo[b]-1,8-naphthyridin-5-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12126132 or 7f), having the structure: , 4-((2-Fluoro-7-methoxyacridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12126137 or 7c), having the structure: , 4-((2-Methoxy-7-(trifluoromethyl)acridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12126138 or 7b), having the structure: , 4-((2,7-Dichloroacridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12126189 or 7d), having the structure: 4-((2,6-Dichloroacridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol (also referred to herein as 12226051 or 7e), having the structure: , or a pharmaceutically acceptable salt thereof (e.g., a HCl salt thereof). IV. PHARMACEUTICAL COMPOSITIONS As described herein, the presently disclosed compounds have antiviral activity. Accordingly, the compounds of the presently disclosed subject matter are useful for the treatment of viral infections in human and in animals. Thus, in some embodiments, the presently disclosed subject matter provides a pharmaceutical composition comprising a compound having a structure of Formula (I) or (II): wherein: X is CH or N; Y is CH or N; R1is H, halo (e.g., Cl or F), or perhaloalkyl (e.g., CF3); R2 is H or halo (e.g., Cl); R3 is halo (e.g., Cl) or alkoxy (e.g., methoxy or another C1-5 alkoxy); R4 is -NH-alkyl, -NH-substituted alkyl, or -N-heterocycle (e.g., morpholine); R7 is H or - CH2N(R9)2; R8is -CH2N(R9)2; and each R9is alkyl (e.g., methyl or ethyl) or wherein two R9together are alkylene (e.g., butylene) and together with the nitrogen atom to which they are attached form a nitrogen-containing heterocycle; or a pharmaceutically acceptable salt thereof. For example, the pharmaceutical composition can include one or more compounds of Formula (I) and / or Formula (II) and a pharmaceutically acceptable carrier. In some embodiments, when the compound has a structure of Formula (I) and when X and Y are each CH, R1 is H, and R2 is Cl, R3 is not methoxy. In some embodiments, when the compound has a structure of Formula (II) and when X is CH, R1is H, and R2is Cl, R3is not methoxy. Thus, in some embodiments, the compound of Formula (I) or (II) is other than, for example, pyronaridine or quinacrine. In some embodiments, when R2 is Cl, R3 is not alkoxy. In some embodiments, when R2 is Cl, R3 is not methoxy. The compounds and compositions of the presently disclosed subject matter can be administered to, for example, a cell, a tissue, or a subject by any of several methods described herein and by others which are known to those of skill in the art. In some embodiments, the compounds of the presently disclosed subject matter are formulated for use by preparing a dilute solution or suspension in a pharmaceutically acceptable aqueous, organic, or aqueous- organic medium. In some embodiments, the compounds are formulated for topical or parenteral administration by intravenous, subcutaneous or intramuscular injection, or for intranasal application; or are prepared in tablet, capsule or aqueous suspension form with conventional excipients for oral administration or as a suppository. Accordingly, the compounds of the presently disclosed subject matter can be formulated, for example, in a wide variety of oral administration dosage forms and carriers. Oral administration can be in the form of tablets, coated tablets, dragée, hard and soft gelatin capsules, solutions, emulsions, syrups or suspensions. Compounds of the presently disclosed subject matter are also efficacious when administered by other routes of administration, including, for example, continuous (intravenous drip), topical parenteral, intramuscular, intravenous, subcutaneous, transdermal (e.g., alone or in combination with a penetration enhancement agent), buccal, nasal, inhalation, and suppository routes, among other routes of administration. In some embodiments, the compound is administered orally, e.g., using a daily or weekly dosing regimen. Thus, in some embodiments, the compounds of the presently disclosed subject matter are provided for use (e.g., in a pharmaceutical composition) for the treatment or prevention of viral infections, particularly coronavirus infections (e.g., SARS-CoV-2 infections), in humans and in animals (e.g., non-human mammals). In some embodiments, the compounds of the presently disclosed subject matter are provided (e.g., in a pharmaceutical composition) for use in the treatment or prevention of a disease or condition caused by (or triggered by) a viral infection (e.g., a SARS-Cov-2 or other coronavirus infection), such as for use in the treatment or prevention of COVID-19. In some embodiments, the compounds of Formula (I) or Formula (II) can be used in dosages from 0.001 – 1000 mg / kg body weight. In some embodiments, the compounds of Formula (I) and / or (II) can be used in dosages from about 0.01 – about 1000 mg / kg body weight. In some embodiments, the compound of Formula (I) or (II) is used in combination with one or more additional therapeutic agents, e.g., one or more additional antiviral or antimicrobial therapeutic agents (i.e., an additional antiviral therapeutic agent that is not a compound of Formula (I) or (II)) and / or one or more additional therapeutic agents used to treat a symptom of a viral infection or a disease caused or triggered by a viral infection or to enhance the immune response of a subject (e.g., pain, fever, inflammation, etc.). The compound of Formula (I) or (II) and the one or more additional therapeutic agents can be provided in a single formulation or co-administered in separate formulations at about the same time or at different times (e.g., different times within the same day, week, or month). As noted above, in some embodiments, the compound of Formula (I) or (II) can be provided as a pharmaceutically acceptable salt. Such salts include, but are not limited to, pharmaceutically acceptable acid addition salts, pharmaceutically acceptable base addition salts, pharmaceutically acceptable metal salts, ammonium and alkylated ammonium salts, and combinations thereof. Acid addition salts include salts of inorganic acids as well as organic acids. Representative examples of suitable inorganic acids include hydrochloric, hydrobromic, hydroiodic, phosphoric, sulfuric, nitric acids and the like. Representative examples of suitable organic acids include formic, acetic, trichloroacetic, trifluoroacetic, propionic, benzoic, cinnamic, citric, fumaric, glycolic, lactic, maleic, malic, malonic, mandelic, oxalic, picric, pyruvic, salicylic, succinic, methanesulfonic, ethanesulfonic, tartaric, ascorbic, pamoic, bismethylene salicylic, ethanedisulfonic, gluconic, citraconic, aspartic, stearic, palmitic, EDTA, glycolic, p-aminobenzoic, glutamic, benzenesulfonic, p-toluenesulfonic acids, sulphates, nitrates, phosphates, perchlorates, borates, acetates, benzoates, hydroxynaphthoates, glycerophosphates, ketoglutarates and the like. Base addition salts include but are not limited to, ethylenediamine, N-methyl- glucamine, lysine, arginine, ornithine, choline, N, N'- dibenzylethylenediamine, chloroprocaine, diethanolamine, procaine, N-benzylphenethylamine, diethylamine, piperazine, tris (hydroxymethyl)- aminomethane, tetramethylammonium hydroxide, triethylamine, dibenzylamine, ephenamine, dehydroabietylamine, N-ethylpiperidine, benzylamine, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, ethylamine, basic amino acids, e. g., lysine and arginine dicyclohexylamine and the like. Examples of metal salts include lithium, sodium, potassium, and magnesium salts and the like. Examples of ammonium and alkylated ammonium salts include ammonium, methylammonium, dimethylammonium, trimethylammonium, ethylammonium, hydroxyethylammonium, diethylammonium, butylammonium, tetramethylammonium salts and the like. In some embodiments, the presently disclosed compounds can further be provided as a solvate. The compound of Formula (I) or (II), or pharmaceutical composition thereof, can be used on a sample either in vitro (for example, on isolated cells or tissues) or in vivo in a subject (i.e. living organism, such as a patient). In some embodiments, the subject or patient is a human subject, although it is to be understood that the principles of the presently disclosed subject matter indicate that the presently disclosed subject matter is effective with respect to all vertebrate species, including mammals, which are intended to be included in the terms “subject” and “patient”. Moreover, a mammal is understood to include any mammalian species for which employing the compositions and methods disclosed herein is desirable, particularly agricultural and domestic mammalian species. As such, the methods of the presently disclosed subject matter are particularly useful in warm-blooded vertebrates. Thus, the presently disclosed subject matter concerns mammals and birds. More particularly provided are methods and compositions for mammals such as humans, as well as those mammals of importance due to being endangered (such as Siberian tigers), of economic importance (animals raised on farms for consumption by humans), and / or of social importance (animals kept as pets or in zoos) to humans, for instance, carnivores other than humans (such as cats and dogs), swine (pigs, hogs, and wild boars), ruminants (such as cattle, oxen, sheep, giraffes, deer, goats, bison, and camels), and horses. Also provided is the treatment of birds, including the treatment of those kinds of birds that are endangered, kept in zoos or as pets (e.g., parrots), as well as fowl, and more particularly domesticated fowl, for example, poultry, such as turkeys, chickens, ducks, geese, guinea fowl, and the like, as they are also of economic importance to humans. Thus, also provided is the treatment of livestock including, but not limited to domesticated swine (pigs and hogs), ruminants, horses, poultry, and the like. In some embodiments, the compound of Formula (I) or (II) (which can also be referred to as the “active ingredient”) can be administered in a pharmaceutically acceptable composition where the compound can be admixed with one or more pharmaceutically acceptable carriers. The term "pharmaceutically acceptable carrier" means a non-toxic material that does not interfere with the effectiveness of the biological activity of the active ingredients. In some embodiments, the pharmaceutically acceptable composition can also contain salts, buffering agents, preservatives, compatible carriers, and optionally other therapeutic agents. In some embodiments, the methods for administration of a compound of Formula (I) or pharmaceutically acceptable composition thereof to a subject include, but are not limited to intravenous injection, oral administration, buccal, topical, subcutaneous administration, intraperitoneal injection, pulmonary, intanasal, intracranial injection, and rectal administration. The particular mode of administering a composition matter depends on various factors, including the distribution and abundance of cells to be treated and mechanisms for metabolism or removal of the comp Actual dosage levels of constituents of the compositions of the presently disclosed subject matter can be varied so as to administer an amount of the composition that is effective to achieve the desired effect for a particular subject and / or target. The selected dosage level can depend upon the activity of the composition and the route of administration. After review of the disclosure herein of the presently disclosed subject matter, one of ordinary skill in the art can tailor the dosages to an individual subject, taking into account the particular formulation, method of administration to be used with the composition, and nature of the target to be treated. Such adjustments or variations, as well as evaluation of when and how to make such adjustments or variations, are well known to those of ordinary skill in the art. The effective amount can be determined by testing the compounds in an in vitro or in vivo model and then extrapolating therefrom for dosages in subjects of interest, e.g., humans. The therapeutically effective amount should be enough to exert a therapeutically useful effect in the absence of undesirable side effects in the subject to be treated with the composition. Pharmaceutically acceptable carriers are well known to those skilled in the art and include, but are not limited to, from about 0.01 to about 0.1M and preferably 0.05M phosphate buffer or 0.8% saline. Such pharmaceutically acceptable carriers can be aqueous or non- aqueous solutions, suspensions and emulsions. Examples of non-aqueous solvents suitable for use in the presently disclosed subject matter include, but are not limited to, propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate. Aqueous carriers suitable for use in the presently disclosed subject matter include, but are not limited to, water, ethanol, alcoholic / aqueous solutions, glycerol, emulsions or suspensions, including saline and buffered media. Oral carriers can be elixirs, syrups, capsules, tablets and the like. Liquid carriers suitable for use in the presently disclosed subject matter can be used in preparing solutions, suspensions, emulsions, syrups, elixirs and pressurized compounds. The active ingredient can be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, a mixture of both or pharmaceutically acceptable oils or fats. The liquid carrier can contain other suitable pharmaceutical additives such as solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavoring agents, suspending agents, thickening agents, colors, viscosity regulators, stabilizers or osmo-regulators. Liquid carriers suitable for use in the presently disclosed subject matter include, but are not limited to, water (partially containing additives as above, e.g. cellulose derivatives, preferably sodium carboxymethyl cellulose solution), alcohols (including monohydric alcohols and polyhydric alcohols, e.g. glycols) and their derivatives, and oils (e.g. fractionated coconut oil and arachis oil). For parenteral administration, the carrier can also include an oily ester such as ethyl oleate and isopropyl myristate. Sterile liquid carriers are useful in sterile liquid form comprising compounds for parenteral administration. The liquid carrier for pressurized compounds disclosed herein can be halogenated hydrocarbon or other pharmaceutically acceptable propellent. Solid carriers suitable for use in the presently disclosed subject matter include, but are not limited to, inert substances such as lactose, starch, glucose, methyl-cellulose, magnesium stearate, dicalcium phosphate, mannitol and the like. A solid carrier can further include one or more substances acting as flavoring agents, lubricants, solubilizers, suspending agents, fillers, glidants, compression aids, binders or tablet-disintegrating agents; it can also be an encapsulating material. In powders, the carrier can be a finely divided solid which is in admixture with the finely divided active compound. In tablets, the active compound is mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. The powders and tablets preferably contain up to 99% of the active compound. Suitable solid carriers include, for example, calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins. Parenteral carriers suitable for use in the presently disclosed subject matter include, but are not limited to, sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's and fixed oils. Intravenous carriers include fluid and nutrient replenishers, electrolyte replenishers such as those based on Ringer's dextrose and the like. Preservatives and other additives can also be present, such as, for example, antimicrobials, antioxidants, chelating agents, inert gases and the like. Carriers suitable for use in the presently disclosed subject matter can be mixed as needed with disintegrants, diluents, granulating agents, lubricants, binders and the like using conventional techniques known in the art. The carriers can also be sterilized using methods that do not deleteriously react with the compounds, as is generally known in the art. The compounds disclosed herein can take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and can contain formulatory agents such as suspending, stabilizing and / or dispersing agents. The compounds disclosed herein can also be formulated as a preparation for implantation or injection. Thus, for example, the compounds can be formulated with suitable polymeric or hydrophobic materials (e.g., as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives (e.g., as a sparingly soluble salt). Alternatively, the active ingredient can be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use. Suitable formulations for each of these methods of administration can be found, for example, in Remington: The Science and Practice of Pharmacy, A. Gennaro, ed., 20th edition, Lippincott, Williams & Wilkins, Philadelphia, Pa.

[0084] For example, formulations for parenteral administration can contain as common excipients sterile water or saline, polyalkylene glycols such as polyethylene glycol, oils of vegetable origin, hydrogenated naphthalenes and the like. In particular, biocompatible, biodegradable lactide polymer, lactide / glycolide copolymer, or polyoxyethylenepolyoxypropylene copolymers can be useful excipients to control the release of active compounds. Other potentially useful parenteral delivery systems include ethylene-vinyl acetate copolymer particles, osmotic pumps, implantable infusion systems, and liposomes. Formulations for inhalation administration contain as excipients, for example, lactose, or can be aqueous solutions containing, for example, polyoxy ethylene-9-auryl ether, glycocholate and deoxycholate, or oily solutions for administration in the form of nasal drops, or as a gel to be applied intranasally. Formulations for parenteral administration can also include glycocholate for buccal administration, methoxysalicylate for rectal administration, or citric acid for vaginal administration.

[0085] Further, formulations for intravenous administration can comprise solutions in sterile isotonic aqueous buffer. Where necessary, the formulations can also include a solubilizing agent and a local anesthetic to ease pain at the site of the injection. Generally, the ingredients are supplied either separately or mixed together in unit dosage form, for example, as a dry lyophilized powder or water free concentrate in a hermetically sealed container such as an ampule or sachet indicating the quantity of active agent. Where the compound is to be administered by infusion, it can be dispensed in a formulation with an infusion bottle containing sterile pharmaceutical grade water, saline or dextrose / water. Where the compound is administered by injection, an ampule of sterile water for injection or saline can be provided so that the ingredients can be mixed prior to administration.

[0086] Suitable formulations further include aqueous and non-aqueous sterile injection solutions that can contain antioxidants, buffers, bacteriostats, bactericidal antibiotics and solutes that render the formulation isotonic with the bodily fluids of the intended recipient; and aqueous and non-aqueous sterile suspensions, which can include suspending agents and thickening agents.

[0087] The compounds of the presently disclosed subject matter can further be formulated for topical administration. Suitable topical formulations include one or more compounds in the form of a liquid, lotion, cream or gel. Topical administration can be accomplished by application directly on the treatment area. For example, such application can be accomplished by rubbing the formulation (such as a lotion or gel) onto the skin of the treatment area, or by spray application of a liquid formulation onto the treatment area.

[0088] In some formulations, bioimplant materials can be coated with the compounds so as to improve interaction between cells and the implant.

[0089] Formulations of the compounds can contain minor amounts of wetting or emulsifying agents, or pH buffering agents. The formulations comprising the compound can be a liquid solution, suspension, emulsion, tablet, pill, capsule, sustained release formulation, or powder. The compounds can be formulated as a suppository, with traditional binders and carriers such as triglycerides.

[0090] Oral formulations can include standard carriers such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, polyvinyl pyrollidone, sodium saccharine, cellulose, magnesium carbonate, etc.

[0091] In some embodiments, the pharmaceutical composition comprising the compound of Formula (I) or (II) can include an agent which controls release of the compound, thereby providing a timed or sustained release compound.

[0092] Accordingly, the presently disclosed pharmaceutical compositions can include pharmaceutically acceptable carriers including physiologically tolerable or acceptable diluents, excipients, solvents, or adjuvants. The compositions are in some embodiments sterile and nonpyrogenic. Examples of suitable carriers include, but are not limited to, water, normal saline, dextrose, mannitol, lactose or other sugars, lecithin, albumin, sodium glutamate, cysteine hydrochloride, ethanol, polyols (propylene glycol, polyethylene glycol, glycerol, and the like), vegetable oils (such as olive oil), injectable organic esters such as ethyl oleate, ethoxylated isosteraryl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum methahydroxide, bentonite, kaolin, agar-agar and tragacanth, or mixtures of these substances, and the like.

[0093] The pharmaceutical compositions can also contain minor amounts of nontoxic auxiliary pharmaceutical substances or excipients and / or additives, such as wetting agents, emulsifying agents, pH buffering agents, antibacterial and antifungal agents (such as parabens, chlorobutanol, phenol, sorbic acid, and the like). Suitable additives include, but are not limited to, physiologically biocompatible buffers (e.g., tromethamine hydrochloride), additions (e.g., 0.01 to 10 mole percent) of chelants (such as, for example, DTPA or DTPA-bisamide) or calcium chelate complexes (as for example calcium DTPA or CaNaDTPA-bisamide), or, optionally, additions (e.g., 1 to 50 mole percent) of calcium or sodium salts (for example, calcium chloride, calcium ascorbate, calcium gluconate or calcium lactate). If desired, absorption enhancing or delaying agents (such as liposomes, aluminum monostearate, or gelatin) may be used. The compositions can be prepared in conventional forms, either as liquid solutions or suspensions, solid forms suitable for solution or suspension in liquid prior to injection, or as emulsions. Pharmaceutical compositions according to the presently disclosed subject matter can be prepared in a manner fully within the skill of the art.

[0094] V. METHODS OF TREATING VIRUS INFECTIONS

[0095] In some embodiments, the presently disclosed subject matter provides a method of treating a viral infection or a disease caused by a viral infection in a subject in need thereof (i.e., a subject who has a viral infection). In some embodiments, the method comprises administering to the subject an effective amount of a compound of Formula (I) or (II): wherein: X is CH or N; Y is CH or N; Ri is H, halo (e.g., Cl or F), or perhaloalkyl (e.g., CF3); R2 is H or halo (e.g., Cl); R3 is halo (e.g., Cl) or alkoxy (e.g., methoxy or another C1-5 alkoxy); R4 is -NH-alkyl, -NH- substituted alkyl, or -N-heterocycle (e.g., morpholine); R7 is H or - CH2N(R9)2; R8 is -CH2N(R9)2; and each R9 is alkyl (e.g., methyl or ethyl) or wherein two R9 together are alkylene (e.g., butylene) and together with the nitrogen atom to which they are attached form a nitrogen-containing heterocycle; or a pharmaceutically acceptable salt or pharmaceutical composition thereof. In some embodiments, when the compound has a structure of Formula (I) and when X and Y are each CH, R1 is H, and R2 is Cl, R3 is not methoxy. In some embodiments, when the compound has a structure of Formula (II) and when X is CH, R1is H, and R2is Cl, R3is not methoxy. Thus, in some embodiments, the compound is other than, for example, pyronaridine or quinacrine. In some embodiments, when R2 is Cl, R3is not alkoxy. In some embodiments, when R2is Cl, R3is not methoxy. In some embodiments, the viral infection is a coronavirus infection. More particularly, the term coronavirus as used herein refers to viruses of the subfamily Orthocoronavirinae and include alphacoronaviruses (e.g., alphacoronavirus 1 (feline coronavirus, canine coronavirus), human coronavirus 229E, human coronavirus NL63, etc); betacoronaviruses (e.g., betacoronavirus 1 (human coronavirus OC43), murine coronavirus, severe acute respiratory syndrome related coronaviruses (SARS-COV-1 and SARS-COV-2), human coronavirus HKU1, Middle East respiratory syndrome coronavirus (MERS-CoV)); gammacoronaviruses (e.g., avian coronavirus); and deltacoronaviruses (e.g., porcine coronavirus HKU15). In some embodiments, the coronavirus is SARS-CoV-1, MERS-CoV, or SARS-CoV-2 and can cause a disease or condition such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), or Coronavirus disease of 2019 (COVID-19). In some embodiments, the viral infection is a SARS-CoV-2 infection and the disease is COVID-19. In some embodiments, the compound has a 50% inhibitory concentration (IC50) against SARS-CoV-2 that is less than about 2.0 micromolar (^M). In some embodiments, the compound has an IC50against SARS-CoV-2 that is less than about 1.0 ^M. In some embodiments, the compound has an IC50against SARS-CoV-2 that is about 0.6 ^M or less (e.g., about 0.40 ^M to about 0.60 ^M). In some embodiments, the IC50against SARS-CoV- 2 is measured in US-OS ACE2 GFP cells.  In some embodiments, the compound has a 50% cytotoxicity concentration (CC50) that is greater than about 4.0 µM. In some embodiments, the compound has a CC50 that is greater than about 5.0 ^M, greater than about 7.0 ^M, greater than about 10 ^M, or greater than about 20.0 ^M. In some embodiments, the compound has a selectivity index (SI) of about 10 or more. In some embodiments, the compound has a SI of about 12 or more, or about 13 or more or about 15 or more. In some embodiments, the compound has a SI of about 15.50. In some embodiments, the compound has a SI of about 12 or more and an ICso against SARS-CoV-2 or about 0.6 pM or less.

[0096] In some embodiments, the compound is selected from the group comprising:

[0097] of a pharmaceutically acceptable salt thereof.

[0098] In some embodiments, the compound is selected from the group comprising:

[0099] The compositions of the presently disclosed subject matter or pharmaceutical compositions comprising these compositions can be administered so that the compositions can have a physiological effect. Administration can occur enterally or parenterally; for example, orally, rectally, intraci stemally, intravaginally, intraperitoneally, locally (e.g., with powders, ointments or drops), or as a buccal or nasal spray or aerosol. Particular parenteral administration methods include intravascular administration (e.g., intravenous bolus injection, intravenous infusion, intra-arterial bolus injection, intra-arterial infusion and catheter instillation into the vasculature), peri- and intra-target tissue injection, subcutaneous injection or deposition including subcutaneous infusion (such as by osmotic pumps), intramuscular injection, and direct application to the target area, for example by a catheter or other placement device.

[0100] Where the administration of the composition is by injection or direct application, the injection or direct application may be in a single dose or in multiple doses. Where the administration of the compound is by infusion, the infusion can be a single sustained dose over a prolonged period of time or multiple infusions.

[0101] The relative amounts of the active ingredient, the pharmaceutically acceptable carrier, and any additional ingredients in a pharmaceutical composition of the presently disclosed subject matter will vary, depending upon the identity, size, and condition of the subject treated and further depending upon the route by which the composition is to be administered. By way of example, the composition may comprise between 0.1% and 100% (w / w) active ingredient.

[0102] In addition to the active ingredient, a pharmaceutical composition of the presently disclosed subject matter can further comprise one or more additional pharmaceutically active agents.

[0103] Controlled- or sustained-release formulations of a pharmaceutical composition of the presently disclosed subject matter can be made using conventional technology.

[0104] As used herein, “additional ingredients” include, but are not limited to, one or more of the following: excipients; surface active agents; dispersing agents; inert diluents; granulating and disintegrating agents; binding agents; lubricating agents; sweetening agents; flavoring agents; coloring agents; preservatives; physiologically degradable compositions such as gelatin; aqueous vehicles and solvents; oily vehicles and solvents; suspending agents; dispersing or wetting agents; emulsifying agents, demulcents; buffers; salts; thickening agents; fillers; emulsifying agents; antioxidants; antibiotics; antifungal agents; stabilizing agents; and pharmaceutically acceptable polymeric or hydrophobic materials. Other “additional ingredients” which may be included in the pharmaceutical compositions of the presently disclosed subject matter are known in the art and described, for example in Gennaro, 1990 and / or Gennaro, 2003, each of which is incorporated herein by reference. Other components such as preservatives, antioxidants, surfactants, absorption enhancers, viscosity enhancers or film forming polymers, bulking agents, diluents, coloring agents, flavoring agents, pH modifiers, sweeteners or taste-masking agents may also be incorporated into the composition. Suitable coloring agents include red, black, and yellow iron oxides and FD&C dyes such as FD&C Blue No. 2, FD&C Red No. 40, and the like. Suitable flavoring agents include mint, raspberry, licorice, orange, lemon, grapefruit, caramel, vanilla, cherry grape flavors, combinations thereof, and the like. Suitable pH modifiers include citric acid, tartaric acid, phosphoric acid, hydrochloric acid, maleic acid, sodium hydroxide, and the like. Suitable sweeteners include aspartame, acesulfame K, thaumatic, and the like. Suitable taste-masking agents include sodium bicarbonate, ion-exchange resins, cyclodextrin inclusion compounds, adsorbates, and the like.

[0105] Typically, dosages of the compound of the presently disclosed subject matter which can be administered to an animal, in some embodiments a human, range in amount from 1 pg to about 100 g per kilogram of body weight of the animal. While the precise dosage administered will vary depending upon any number of factors, including but not limited to, the type of animal and type of disease state being treated, the age of the animal, the size of the animal, the gender of the animal, the condition of the animal, and the route of administration. In some embodiments, the dosage of the compound will vary from about 1 mg to about 10 g per kilogram of body weight of the animal. In another aspect, the dosage will vary from about 10 mg to about 1 g per kilogram of body weight of the animal.

[0106] The compositions can be administered to an animal as frequently as several times daily, or it can be administered less frequently, such as once a day, once a week, once every two weeks, once a month, or even less frequently, such as once every several months or even once a year or less.

[0107] Suitable preparations include injectables, either as liquid solutions or suspensions, however, solid forms suitable for solution in, suspension in, liquid prior to injection, may also be prepared. The preparation may also be emulsified, or the compositions encapsulated in liposomes. The active ingredients are often mixed with excipients which are pharmaceutically acceptable and compatible with the active ingredient. Suitable excipients are, for example, water saline, dextrose, glycerol, ethanol, or the like and combinations thereof. In addition, if desired, the preparation can also include minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents, and / or adjuvants.

[0108] In some embodiments, the presently disclosed subject provides a compound for use in the preparation of a medicament for treating a viral infection or a disease caused by a viral infection, wherein the compound is a compound of Formula (I) or Formula (II). IN some embodiments, the viral infection is a coronavirus infection. In some embodiments, the coronavirus infection is a SARS-CoV-2 infection. In some embodiments, the medicament comprises more than one compound of Formula (I) and / or Formula (II). In some embodiments, the medicament comprises a compound selected from the group comprising: or a pharmaceutically acceptable salt thereof.

[0109] EXAMPLES

[0110] The following Examples have been included to provide guidance to one of ordinary skill in the art for practicing representative embodiments of the presently disclosed subject matter. In light of the present disclosure and the general level of skill in the art, those of skill can appreciate that the following Examples are intended to be exemplary only and that numerous changes, modifications, and alterations can be employed without departing from the scope of the presently disclosed subject matter. EXAMPLE 1

[0111] COMPOUND SYNTHESIS

[0112] All reagents and solvents were purchased from commercial suppliers (AlfaAesar, Acros, Chimmed) and used without further purification. The1H and13C spectra were recorded on a Bruker AC-300 (300 MHz,1H) or a Bruker AC-200 (50 MHz,13C) NMR spectrometers (Bruker Corporation, Billerica, Massachusetts, United States of America). Chemical shifts were measured in DMSO-de or CDCh using tetramethylsilane as an internal standard and reported as ppm values. The following abbreviations are used to indicate multiplicity: s, singlet; d, doublet; t, triplet; m, multiplet; dd, doublet of doublets; brs, broad singlet. Mass spectra were recorded on a Finnigan MAT INCOS 50 quadrupole mass spectrometer (Thermo Finnigan, San Jose, California, United States of America) (electrospray ionization (El), 70 eV) with direct injection. The purity of the final compounds was analyzed by analytical high-performance liquid chromatography (HPLC) on an Elute HPLC system (Bruker Daltonik, Heidelberg, Germany) equipped with an Azura UVD 2. IS UV detector (Knauer, Berlin, Germany) with a wavelength at 254 nm and acquisition rate at 1 Hz. Chromatographic separation was carried out on an Acquity HSS T3 column (2.1 x 100 mm, 1.3 pm, 100 A) at 30 °C, sample injection volume - 2.0 pL. A mobile phase consisting of 0.1 % formic acid in water (A), 0.1 % formic acid in acetonitrile (B) was programmed with gradient elution of 30-95% at a flow rate of 250 pL / min. Mass spectrometric detection was operated in the positive ion mode. Data were processed using Compass DataAnalysis 5.1 software (Bruker Daltonik, Heidelberg, Germany). All final compounds were > 95 % pure. Elemental analysis (% C, H, N) was performed on a EURO EA elemental analyzer (HEKAtech, Wegberg, Germany). Melting points were determined on an Electrothermal 9001 melting point apparatus (Electrothermal, Rochford, United Kingdom) (10 °C per min) and were uncorrected. Merck KGaA silica gel 60 F254 plates (Merck Group, Darmstadt, Germany) were used for analytical thin-layer chromatography. Spots were detected by a UV lamp. Column chromatography was performed using silica gel Merck 60 (70-230 mesh; Merck Group, Darmstadt, Germany). Yields refer to purified products and were not optimized.

[0113] 4-Amino-2,6-bis((dimethylamino)methyl)phenol, 4-amino-2,6-bis(pyrrolidin-l- ylmethyl)phenol, and 4-amino-2-(pyrrolidin-l-ylmethyl)phenol were prepared according to the procedures as described.21, 22The synthetic procedures are described in the Supporting information. Compounds 5, 6, 7g, 8g were synthesized as previously described,17their physicochemical properties are identical to those described in Puhi et alY1 General procedure for the synthesis of benzoic acids 3a-h

[0114] The corresponding amine 2 (2.4 equiv.), potassium carbonate (2 equiv.) and copper (0.4 equiv.) were consistently added to a solution of the corresponding chloro-derivative 1 (1 equiv.) in dry DMF (20 mL). The resulting suspension was stirred at reflux for 8 h and then at room temperature for 16 h. The mixture was poured into hot water (60 mL), stirred for 1 h and filtered. Ethyl acetate (60 mL) was added to the remaining aqueous solution. The aqueous layer was separated, and the organic layer was washed with fresh water (2x20 mL). The combined aqueous fractions were acidified with 2M hydrochloric acid solution to pH 2 and extracted with ethyl acetate (2x40 mL). The combined organic layers were washed with water, dried with Na2SO4 and evaporated in vacuo. The residue was treated with / / -hexane and the precipitate was filtered to afford the corresponding product 3a-h. These intermediates were used without further purification:

[0115] 5-Chloro-2-((4-methoxyphenyl)amino)benzoic acid 3a

[0116] Yield 49 %, mp. 198-200 °C. MS (El): m / z 277.

[0117] 2-((4-Methoxyphenyl)amino)-5-(trifluoromethyl)benzoic acid 3b Yield 41 %, mp. 186-190 °C. MS (El): m / z 311.

[0118] 5-Fluoro-2-((4-methoxyphenyl)amino)benzoic acid 3c Yield 47 %, mp. 216-218 °C. MS (El): m / z 261.

[0119] 4-Chloro-2-((4-methoxyphenyl)amino)benzoic acid 3d Yield 50 %, mp. 204-208 °C. MS (El): m / z 277.

[0120] 5-Chloro-2-((4-chlorophenyl)amino]benzoic acid 3e Yield 56 %, mp. 227-230 °C. MS (El): m / z 282.

[0121] 2-((4-Methoxyphenyl)amino)nicotinic acid 3f

[0122] Yield 58 %, mp. 216-218 °C. MS (El): m / z 244.

[0123] 5-Chloro-2-((6-methoxypyridin-3-yl)amino)benzoic acid 3g Yield 40 %, mp. 182-186 °C. MS (El): m / z 278.

[0124] 4-Chloro-2-((4-chlorophenyl)amino)benzoic acid 3h Yield 45 %, mp. 224-226 °C. MS (El): m / z 282.

[0125] General procedure for the synthesis of acridines and naphthyridines 4a-h

[0126] Triethylamine hydrochloride (0.8 equiv.) was added portion-wise to a suspension of benzoic acid 3 (1 equiv.) in phosphorus oxychloride (3 mL), and the resulting mixture was stirred at reflux for 5-6 h. Then the mixture was cooled and poured on ice. After 30-min stirring ammonia solution was added dropwise to pH 8, the precipitate was filtered, washed with ethanol and / / -hexane to afford the desired product.

[0127] 2.9-Dichloro-7-methoxyacridine 4a

[0128] Yield 95 %, mp. 185-186 °C. MS (El): m / z 278.

[0129] 9-Chloro-2-methoxy-7-(trifluoromethyl)acridine 4b Yield 93%, mp. 196-200 °C. MS (El): m / z 311. 9-Chloro-2-fluoro-7-methoxyacridine 4c Yield 95%, mp. 180-182 °C. MS (El): m / z 261.

[0130] 6.9-Dichloro-2-methoxyacridine 4d

[0131] Yield 92%, mp. 184-186 °C. MS (El): m / z 278.

[0132] 2.7.9-Trichloroacridine 4e

[0133] Yield 94%, mp. 216-218 °C. MS (El): m / z 282.

[0134] 5-Chloro-7-methoxybenzo[Z>]-l,8-naphthyridine 4f Yield 88%, mp. Tra=188-192 °C. MS (El): m / z 244. 7, 10-Dichloro-2-methoxybenzo[Z>]-l,5-naphthyridine 4g Yield 96%, mp. 178-182 °C. MS (El): m / z 279.

[0135] 2.6.9-Trichloroacridine 4h

[0136] Yield 93%, mp. 212-214 °C. MS (El): m / z 282.

[0137] General procedure for the synthesis of acridines and naphthyridines 7a-g and 8a-g

[0138] 4-Amino-2,6-bis(pyrrolidin-l-ylmethyl)phenol (1 equiv., in the case of 7a-g) or 4- amino-2-(pyrrolidin-l-ylmethyl)phenol (1 equiv., in the case of 8a-g) was added to a suspension of 4 (1 equiv.) in dry DMF (7 mL), and the reaction mixture was stirred at 100 °C for 1-2 h (TLC control chlorofomrmethanol 9: 1). If a precipitate was observed, it was filtered and washed with DMF, ethyl acetate and ether to afford the desired product. If a solution was observed, it was cooled, poured into water and extracted with ethyl acetate. The separated aqueous fraction was alkalized with an aqueous NaHCCh solution to pH 2 and extracted with ethyl acetate (2x40 mL). The combined organic layers were washed with water, dried with Na2SO4 and not fully evaporated in vacuo. The remaining organic solution was acidified with hydrogen chloride solution 3M in methanol to pH 2 and fully evaporated in vacuo. The residue was recrystallized from a 1 : 1 mixture of ether: ethyl acetate or other indicated mixture and washed with acetone and ether to afford the desired product. Data from1H NMR (200 MHz, DMSO-de) and13C NMR (50 MHz, DMSO-de) is described below. 4-((2-Chloro-7-methoxyacridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol 7a (12126131) Yield 75 %, mp.207-210 °C (МеOH:ethyl acetate 1:2).1H NMR (200 MHz; DMSO- d6; δ, ppm; J, Hz): 1.92 (brs, 8H, 4CH2,pyr), 3.44 (brs, 8H, 4CH2,pyr), 3.76 (s, 3H, CH3), 4.46 (s, 4H, 2CH2), 7.64-7.78 (m, 4H, 2CHph, HC(6,8)), 7.93 (d, 1H, HC(3), J = 9.1), 8.05-8.27 (m, 3H, HC(1,4,9), 10.44 (s, 1H, NH), 10.80 (s, 1H, NH), 11.66 (s, 1H, OH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.40, 51.13, 52.39, 56.09, 103.46, 114.05, 115.21, 121.20, 121.66, 121.88, 124.44, 127.97, 128.40, 130.16, 133.43, 134.22, 135.72, 137.74, 152.33, 153.81, 155.73. MS (EI): m / z 517. Anal. calcd for C30H33ClN4О2: C, 69.69; H, 6.43; N, 10.84. Found: C, 69.73; H, 6.46; N, 10.89. 4-((2-Methoxy-7-(trifluoromethyl)acridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol hydrochloride 7b (12126138) Yield 71 %, mp.223-225 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.93 (brs, 8H, 4CH2,pyr), 3.12 (brs, 8H, 4CH2,pyr), 3.78 (s, 3H, CH3), 4.46 (s, 4H, 2CH2), 7.70- 7.89 (m, 4H, HC(3,5,1`,3`)), 8.01-8.25 (m, 2H, HC(4`,6)), 8.31 (d, 1H, HC(5`), J = 9.0), 8.54 (s, 1H, HC(8`)), 10.48 (s, 1H, NH), 10.80 (s, 1H, NH), 12.04 (s, 1H,OH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.37, 51.14, 52.40, 56.15, 103.93, 112.03, 115.48, 120.91, 121.13, 121.23, 121.98, 122.73, 123.37, 124.26, 124.36, 124.43, 126.32, 128.55, 129.15, 130.25, 133.20, 136.09, 140.60, 154.17, 155.90. MS (EI): m / z 550. Anal. calcd for C31H33F3N4О2: C, 67.62; H, 6.04; N, 10.18. Found: C, 67.57; H, 6.07; N, 10.20. 4-((2-Fluoro-7-methoxyacridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol hydrochloride 7c (12126137) Yield 62 %, mp. 240 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 2.00 (brs, 8H, 4CH2,pyr), 3.74 (s, 3H, CH3), 4.44 (brs, 4H, 2CH2), 7.71 (brs, 4H, HC(3,5,1`,8`), 7.83-8.57 (m, 4H, HC(3`,4`,5`,6`), 10.68 (brs, 2H, NH, H), 11.53 (s, 1H, OH), 15.57 (br s, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.40, 51.29, 52.49, 55.99, 103.02, 103.26, 108.85, 109.34, 113.53, 114.22, 114.36, 121.73, 123.19, 124.17, 128.27, 129.83, 133.15, 135.91, 136.37, 152.28, 153.54, 154.94, 155.57, 159.77, 160.01, 168.16, 169.99. MS (EI): m / z 500. Anal. calcd for C30H33FN4О2: C, 71.98; H, 6.64; N, 11.19. Found: C, 71.94; H, 6.67; N, 11.17. 4-((2,7-Dichloroacridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol hydrochloride 7d (12126189) Yield 85 %, mp. 238-240 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.94 (br s, 8H, 4CH2,pyr), 3.25-3.62 (m, 8H, 4CH2,pyr), 4.49 (s, 4H, 2CH2), 7.78 (s, 2H, HC(3, 5)), 8.00 (d, 2H, HC(4`,5`), J = 9.1), 8.17 (d, 2H, HC(3`,6`), J = 9.2), 8.32 (s, 2H, HC(1`, 8`)),10.47-10.88 (m, 2H, NH), 12.12 (brs, 1H, NH), 15.50 (brs, 1H, OH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.42, 51.05, 52.37, 114.57, 121.49, 122.03, 124.85, 128.27, 130.06, 135.27, 138.77, 153.45, 154.25. MS (EI): m / z 521. Anal. calcd for C29H30Cl2N4О: C, 66.79; H, 5.80; N, 10.74. Found: C, 67.83; H, 5.87; N, 10.79.

[0139] 4-((2,6-Dichloroacridin-9-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol hydrochloride 7e (12226051) Yield 82 %, mp.240-244 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.95 (brs, 8H, 4CH2,pyr), 4.45 (s, 8H, 4CH2,pyr), 7.39 (d, 1H, HC(3`), J = 9.2), 7.67 (s, 2H, HC(3,5)), 7.81-8.28 (m, 4H, HC(4`,5`,7,`8`)), 8.44 (brs, 1H, HC(1`)), 9.92-11.36 (brs, 1H, NH, OH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.44, 51.44, 52.66, 112.82, 115.54, 116.00, 117.85, 121.20, 122.28, 123.95, 124.91, 128.03, 128.09, 128.67, 129.11, 134.89, 138.96, 139.30, 141.16, 153.80. MS (EI): m / z 521. Anal. calcd for C29H30Cl2N4О: C, 66.79; H, 5.80; N, 10.74. Found: C, 66.83; H, 5.84; N, 10.76. 4-((7-Methoxybenzo[b]-1,8-naphthyridin-5-yl)amino)-2,6-bis(pyrrolidin-1-ylmethyl)phenol hydrochloride 7f (12126132) Yield 62 %, mp. 217-220 °C (decomp.). (EtOH:MeOH 1:1).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.94 (s, 8H, 4CH2,pyr), 3.24 (s, 8H, 4CH2,pyr), 3.81 (s, 3H, CH3), 4.43 (s, 4H, 2CH2), 7.30 (s, 1H, HC(1)), 7.60 (s, 3H, 2CHph, HC(3)), 7.92 (s, 2H, HC(4,7), 8.34 (brs, 1H, HC(8)), 8.88 (brs, 1H, HC(6)), 11.4-13.3 (brs, 4H, NH, OH).13С NMR (50 MHz; DMSO- d6; δ, ppm): 22.47, 51.65, 52.66, 56.04, 105.39, 117.89, 118.25, 120.51, 122.35, 124.58, 126.48, 126.64, 127.81, 135.60, 136.03, 148.77, 152.66, 153.87, 155.38. MS (EI): m / z 483. Anal. calcd for C29H33N5О2: C, 72.02; H, 6.88; N, 14.48. Found: C, 72.06; H, 6.92; N, 14.52. 4-((2-Chloro-7-methoxyacridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol hydrochloride 8a (12126134) Yield 89 %, mp. 255 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.94 (s, 4H, 2CH2,pyr), 3.75 (s, 3H, CH3), 4.28 (s, 2H, CH2), 7.19 (d, 1H, HC(6), J = 8.7), 7.31 (s, 1H, HC(1`)), 7.65 (m, 3H, HC(3,5,8`), 7.88 (d, 1H, HC(5`), J = 8.4), 8.11 (m, 3H, HC(3`,4`,6`), 10.0-12.0 (brs , 4H, NH, OH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.46, 50.96, 52.50, 55.82, 103.87, 113.94, 114.08, 115.09, 116.94, 118.70, 121.55, 121.94, 124.36, 127.21, 127.63, 128.56, 132.61, 133.80, 136.20, 138.29, 152.01, 155.38, 155.56. MS (EI): m / z 433. Anal. calcd for C25H24ClN3О2: C, 69.20; H, 5.58; N, 9.68. Found: C, 69.25; H, 5.62; N, 9.71. 4-((2-Methoxy-7-(trifluoromethyl)acridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol hydrochloride 8b (12126135) Yield 77 %, mp. 265 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.69-2.17 (brm, 4H, 2CH2,pyr), 3.08 (brs, 2H, CH2,pyr), 3.77 (s, 3H, CH3), 4.30 (s, 2H, CH2), 7.19 (d, 1H, HC(6), J = 8.7), 7.38 (d, 1H, HC(3`), J = 8.4), 7.71 (brs, 2H, HC(3,5)), 7.84 (s, 1H, HC(1’)), 7.99-8.31 (m, 3H, HC(4`,5`,6`), 8.41 (s, 1H, HC(8`)), 10.73 (brs, 1H, NH), 10.96 (brs, 1H, H), 11.87 (brs, 1H, OH), 15.28, (brs, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.43, 50.77, 52.42, 55.95, 103.88, 111.36, 115.00, 116.82, 118.87, 120.89, 121.04, 122.34, 122.97, 124.31, 124.39, 126.31, 127.76, 128.33, 129.00, 129.28, 131.63, 135.77, 140.66, 154.19, 155.78, 155.96. MS (EI): m / z 467. Anal. calcd for C26H24F3N3О2: C, 66.80; H, 5.17; N, 8.99. Found: C, 66.83; H, 5.23; N, 9.02. 4-((2-Fluoro-7-methoxyacridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol hydrochloride 8c (12126140) Yield 87 %, mp. >270 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.93 (brs, 4H, 2CH2,pyr), 3.09 (s, 2H, CH2,pyr), 3.71 (s, 3H, CH3), 4.28 (s, 2H, CH2), 7.18 (d, 1H, HC(6), J = 8.7), 7.35 (dd, 1H, HC(5), J = 8.7, 2.4), 7.66 (m, 3H, HC(3,1`,8`)) 7.75-7.99 (m, 2H, HC(3’,4’)), 8.11 (d, 1H, HC(5`), J = 9.1), 8.22 (dd, 1H, HC(6`), J = 9.2, 5.3), 10.66 (s, 1H, NH), 10.90 (s, 1H, H, NH), 11.37 (s, 1H, OH), 15.36 (br s, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.46, 50.87, 52.48, 55.72, 103.15, 108.78, 109.29, 113.37, 113.55, 114.21, 116.67, 118.58, 121.14, 122.27, 123.98, 124.53, 127.61, 127.97, 129.00, 131.86, 135.67, 136.34, 152.36, 154.62, 155.36, 155.49, 159.45. MS (EI): m / z 417. Anal. calcd for C25H24FN3О2: C, 71.92; H, 5.79; N, 10.07. Found: C, 71.97; H, 5.84; N, 10.11. 4-((2,7-Dichloroacridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol hydrochloride 8d (12126191) Yield 67 %, mp. >270 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 2.01 (brs, 4H, 2CH2,pyr), 3.09 (brs, 4H, CH2,pyr), 4.30 (s, 2H, CH2), 7.21 (d, 1H, HC(6), J = 8.7), 7.37 (dd, 1H, HC(5), J = 8.6, 2.3), 7.66 (d, 1H, HC(3), J = 2.3), 7.85-8.05 (m, 2H, HC(4`,5`)), 8.14 (d, 2H, HC(3`,6`), J = 9.1),8.26 (brs, 2H, HC(1`,8`)), 10.66 (s, 1H, NH), 10.95 (s, 1H, NH), 12.1 (brs, 1H, OH), 15.05 (br s, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.48, 50.77, 52.50, 114.12, 117.03, 118.94, 121.41, 124.77, 127.57, 128.10, 128.92, 131.44, 135.28, 138.71, 153.55, 156.18. MS (EI): m / z 438. Anal. calcd for C24H21Cl2N3О: C, 65.76; H, 4.83; N, 9.59. Found: C, 65.79; H, 4.85; N, 9.62. 4-((2,6-Dichloroacridin-9-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol hydrochloride 8e (12226052) Yield 70 %, mp. >270 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 2.02 (brs, 4H, 2CH2,pyr), 3.05 (brs, 4H, 2CH2,pyr), 4.28 (s, 2H, CH2), 7.19 (d, 1H, HC(6), J = 8.6), 7.27-7.52 (m, 2H, HC(3`,5)), 7.59 (s, 1H, HC(3)), 7.85-8.27 (m, 4H, HC(1`,3`,7`,8`), 8.40 (s, 1H, HC(5`)), 10.59 (brs, 1H, NH), 10.88 (brs, 1H, NH), 11.95 (brs, 1H, OH), 14.91 (brs, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.42, 50.86, 52.60, 111.94, 114.59, 117.00, 117.79, 118.88, 121.19, 124.08, 124.70, 127.29, 128.10, 128.31, 128.52, 135.33, 138.74, 139.69, 140.90, 154.28, 155.97. MS (EI): m / z 438. Anal. calcd for C24H21Cl2N3О: C, 65.76; H, 4.83; N, 9.59. Found: C, 65.72; H, 4.79; N, 9.63. 4-((7-Methoxybenzo[b]-1,8-naphthyridin-5-yl)amino)-2-(pyrrolidin-1-ylmethyl)phenol hydrochloride 8f (12226053) Yield 75 %, mp. >270 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 2.01 (brs, 4H, 2CH2,pyr), 3.06 (s, 2H, CH2,pyr), 3.84 (s, 3H, CH3), 4.27 (s, 2H, CH2), 7.11 (s, 1H, HC(3)), 7.23 (d, 1H, HC(6), J = 8.7), 7.40 (m, 3H, HC(5,6’,8’)), 7.50-7.88 (m, 1H, HC(2`)), 8.07 (m, 2H, HC(5`), NHpyr), 8.40 (d, 1H, HC(3`), J = 7.5), 9.01 (d, 1H, HC(1`), J = 3.3), 10.85 (brs, 1H, NH), 11.05 (brs, 1H, NH), 12.1 (brs, 1H, OH), 14.44 (brs, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 22.49, 50.70, 52.49, 56.18, 104.03, 107.76, 115.08, 116.96, 118.80, 118.95, 119.49, 120.95, 127.44, 128.36, 128.97, 131.59, 135.71, 147.84, 154.95, 155.84, 155.94, 156.91. MS (EI): m / z 400. Anal. calcd for C24H24N4О2: C, 71.98; H, 6.04; N, 13.99. Found: C, 72.01; H, 6.06; N, 13.97. General procedure for the synthesis of acridines and naphthyridines 9a-d N1,N1-Diethylpentane-1,4-diamine (6 equiv.) was added to a suspension of 4 (1 equiv.) in dry DMF (7 mL), and the reaction mixture was stirred at 100 °C for 6 h. Then the solution was cooled, diluted with waster and extracted with ethyl acetate (3x30 mL). The organic layer was acidified by an aqueous solution of hydrochloric acid to pH 2, and the aqueous layer was separated. The organic layer was additionally washed with water until the aqueous layer became pH 7. The combined aqueous solution was evaporated in vacuo. A mixture of ethyl acetate:isopropanol (5:1) was added to the residue and the resulting mixture was boiled until crystals appeared. The precipitate was filtered, washed with isopropanol, ethyl acetate and ether to afford the desired product. N4-(2-Chloro-7-methoxyacridin-9-yl)-N1,N1-diethylpentane-1,4-diamine hydrochloride 9a (12126136) Yield 56 %, mp.232-236 °C.1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.10 (t, 6H, 2CH3, J = 6.7), 1.65 (d, 5H, CH3CHCH2, J = 6.0), 1.88 and 2.11 (s and s, 1H and 1H, CH2CH2N), 2.93 (s, 2H, CH2N), 3.36 (s, 4H, 2CH2-CH3), 4.00 (s, 3H, OCH3), 4.59 (brs, 1H, CH), 7.71 (d, 1H, HC(6), J = 9.2), 8.03 (dt, 4H, HC(3,4,5,8), J = 18.0, 9.5), 8.64 (s, 1H, HC(1)), 9.55 (brs, 1H, NH), 10.44 (s, 1H, NH), 14.93 (s, 1H, OH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 8.17, 19.96, 20.77, 33.64, 49.80, 55.30, 56.22, 104.12, 112.79, 113.36, 120.66, 120.98, 124.04, 127.45, 127.62, 134.28, 135.35, 137.54, 155.48. MS (EI): m / z 399. Anal. calcd for C26H30ClN3О: C, 69.07; H, 7.56; N, 10.51. Found: C, 69.11; H, 7.59; N, 10.48. N1,N1-Diethyl-N4-(2-methoxy-7-(trifluoromethyl)acridin-9-yl)pentane-1,4-diamine hydrochloride 9b (12126142) Yield 70 %, mp. 212 °C (decomp.).1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.12 (t, 6H, 2CH3, J = 6.7), 1.70 (d, 5H, CH3CHCH2, J = 6.1), 1.93 and 2.14 (s and s, 1H and 1H, CH2CH2N), 2.94 (s, 2H, CH2N), 3.38 (s, 4H, 2CH2-CH3), 4.02 (s, 3H, OCH3), 4.57 (brs, 1H, CH), 7.87 (dd, 1H, HC(3)), 7.94-8.37 (m, 4H, HC(4,5,6,8)), 8.83 (brs, 1H, HC(1)), 10.08 (s, 1H, NH), 10.49 (s, 1H, NH), 15.03 (s, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 8.12, 8.17, 19.90, 20.58, 33.46, 45.80, 49.72, 55.73, 56.45, 104.48, 110.46, 114.04, 120.33, 120.63, 121.24, 121.68, 122.28, 122.93, 124.17, 126.64, 127.54, 129.36, 132.07, 135.30, 140.72, 155.85, 156.95. MS (EI): m / z 433. Anal. calcd for C24H30F3N3О: C, 66.49; H, 6.98; N, 9.69. Found: : C, 66.54; H, 7.02; N, 9.73. N4-(2,7-Dichloroacridin-9-yl)-N1,N1-diethylpentane-1,4-diamine hydrochloride 9c (12126190) Yield 61 %, mp.256-258 °C.1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 1.15 (t, 6H, 2CH3, J = 6.7), 1.63 (d, 5H, CH3CHCH2, J = 5.7), 1.94 and 2.12 (s and s, 1H and 1H, CH2CH2N), 2.98 (s, 2H, CH2N), 3.26 (brs, 4H, N(CH2CH3)2), 4.56 (brs, 1H, CH), 7.84-8.28 (m, 4H, HC(3,4,5,6)), 8.67 (brs, 2H, HC(1,8)), 9.84 (brs, 1H, NH), 10.56 (brs, 1H, NH), 15.02 (brs, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 8.27, 19.92, 20.43, 33.42, 46.11, 50.11, 55.24, 113.25, 121.15, 124.64, 127.97, 135.02, 138.75, 155.77. MS (EI): m / z 404. Anal. calcd for C21H26Cl2N3: C, 65.35; H, 6.73; N, 10.39. Found: C, 65.38; H, 6.78; N, 10.34. N4-(7-chloro-2-methoxybenzo[b][1,5]naphthyridin-10-yl)-N1,N1-diethylpentane-1,4-diamine hydrochloride 9d (12226050) Yield 64 %, mp.160-164 °C.1H NMR (200 MHz; DMSO-d6; δ, ppm; J, Hz): 0.98-1.34 (m, 6H, 2CH3), 1.51 (d, 3H, CH3, J = 6.2), 1.80 (brs, 4H, 2CH2), 2.08 (s, 1H, CH), 2.82-3.22 (m, 6H, 3CH2N), 4.02 (s, 3H, OCH3), 6.06 (s, 1H, NH), 7.57 (d, 1H, HC(7), J = 9.2), 7.61 (dd, 1H, HC(3), J = 1.5, 9.0), 8.06 (d, 1H, HC(4), J = 1.5), 8.38 (d, 1H, HC(8), J = 9.2), 9.00 (s, 1H, HC(5)), 9.35 (s, 1H, NH), 10.49 (s, 1H, NH), 15.04 (s, 1H, NH).13С NMR (50 MHz; DMSO-d6; δ, ppm): 8.23, 20.21, 21.39, 32.84, 45.77, 45.91, 50.23, 52.94, 54.42, 113.52, 117.54, 121.76, 124.33, 124.55, 127.22, 131.06, 135.04, 137.89, 138.72, 152.29, 158.21. MS (EI): m / z 400. Anal. calcd for C22H29ClN4O: C, 65.90; H, 7.29; N, 13.97. Found: C, 65.98; H, 7.36; N, 13.93. Tables 1-3 below show the areas, area percentages, signal-to-noise (S / N) ratios, and retention times (RT) of the peaks of the HPLC traces of compounds 7a, 7e, and 9c. Table 1. HPLC of Compound 7a. Table 2. HPLC of Compound 7e. Table 3. HPLC of Compound 9c. Discussion: Derivatives and analogs based on the pyronaridine core were synthesized according to Schemes 3 and 4, below. The benzoic acids 3a-h were obtained under the Ullmann reaction conditions from commercial aryl chlorides 1a-e and arylamines 2a-c (Scheme 3). Subsequent cyclization of 3a-h with phosphorus oxychloride led to afford the desired intermediate acridines and naphthyridines 4a-h in high yields. Further, some compounds 4a-h were reacted with the corresponding amines listed in Scheme 4 in DMF medium at reflux or 100 °C to give the final products 7a-g and 8a-g.

[0140] Reagents and conditions: a) K2CO3, Cu, DMF, reflux then rt; b) POCI3, (C2H5)3N HCI, reflux

[0141] Scheme 3. Synthesis of acridines and naphthyridines 4a-h.

[0142]

[0143] ‘Pyronaridine

[0144] Scheme 4. Synthesis of 9-aminoacridines 7a-g and 8a-g.

[0145] EXAMPLE 2

[0146] IN VITRO ACTIVITY

[0147] SARS-CoV-2-infected US-OS ACE2 GFP cells were generated according to a previously described procedure.23In short, U2-OS ACE2 GFP cells were split one day before infection. Compounds were resuspended in DMSO or FEO at 20 mM or 5 mM. These concentrations were sufficient to solubilize the molecules. The experimental compounds were incubated for 2 hours at 37°C in 100 «L of growth medium (DMEM 10% FCS 1% PS). 10 / / L of SARS-CoV-2 virus (strain BetaCoV / France / IDF0372 / 2020) were then added to each well (final MOI 0.1). Cells are incubated at 37°C for 20 hours, fixed with PFA 8% 30 min at RT, and washed with PBS. To stain the nuclei and measure the viability, 100 uL of Hoechst solution is added. The plates are read with an automated confocal microscope (Opera Phoenix), which measures the number of infected cells (GFP signal) and viability (Hoechst signal). The compounds were tested from 50 «M to 0.64 nM with serial 5-fold dilutions.

[0148] Results and Discussion:

[0149] The antiviral activity against SARS-CoV-2, cytotoxicity in U2-OS ACE2 GFP cells, and selectivity index (SI) for the synthesized compounds are summarized in Tables 4 and 5, below. The quinacrine derivatives in Table 4 were more active when bearing a 2-chloro substituent compared to a 3-chloro substituent (for example, quinacrine is less active than 12126136 (9a) and 12126290 (9c)). For the symmetric pyronaridine derivatives in Table 5 (R4 = Py), compounds bearing trifluoromethyl substituents at the 2-position (Ri as drawn) were more active than the 2-chloro compounds and had comparable antiviral activity to the 3-chloro derivatives (R2 as drawn). A significant relationship was not observed regarding the 2- and 3-chloro derivatives with respect to activity. For the asymmetric pyronaridine derivatives (Table 5, R4 = H), 2-chloro substituents were generally more active than the 3-chloro derivatives, and the more electronegative fluoro- and trifluoromethyl groups did not increase activity to a significant degree. The presence of a chloro- or methoxy substituent at R3 did not have a significant effect on activity. Lastly, the introduction of an additional nitrogen atom into the ring system did not affect antiviral activity significantly but did result in lower cytotoxicity. Overall, antiviral activity appeared dependent on both the identity of the side chain at the acridine 9-position as well as the halogenation pattern around the central ring system. Table 4. SARS-CoV-2 inhibition in U2-OS ACE2 GFP cells (IC50, µM), cytotoxicity (CC50, µM), and selectivity index (SI) of quinacrine derivatives. Table 5. SARS-CoV-2 inhibition in U2-OS ACE2 GFP cells (IC50, µM), cytotoxicity (CC50, µM), and selectivity index (SI) of pyronaridine derivatives.

[0150]

[0151] Compound X Y R1R2R3R4IC50(pM) CC50(pM) SI

[0152] Overall, compounds 12226051 and 12126190 were among the most active compounds and displayed high selectivity indexes (SI > 10). Compounds 12126134, 12126136 and 12126138 were also comparable in antiviral activity, but displayed higher cytotoxicity and lower selectivity indexes (SI < 10). Subsequent studies of these compounds in other common cells lines such as A549-ACE2, Huh-7, and Caco-2 can be performed to determine cell-type specific activity against SARS-CoV-2.20,24While, the most active compounds are still less active than remdesivir (ICso = 0.02-0.05 / / M),7, 8nonetheless, these findings suggest that compounds 12226051 and 12126190 support further investigation of the repurposing of pyronaridine and quinacrine as antivirals against SARS-CoV-19 and illustrate how they can be used to generate new analogs with improved properties (e.g., compared to quinacrine).

[0153] While there has been considerable progress made on COVID-19 drug discovery in the over 3 years since the pandemic began with preclinical and clinical molecules showing activity,1, 2there is still a need to identify promising lead compounds. This can be particularly important as the virus mutates and overcomes existing small-molecule antivirals. As described herein, 9-aminoacridines appear suitable to provide a scaffold for further optimization as antivirals.14'16

[0154] REFERENCES

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[0178] It will be understood that various details of the presently disclosed subject matter may be changed without departing from the scope of the presently disclosed subject matter. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation.

Claims

CLAIMSWhat is claimed is:

1. A compound having a structure of Formula (I) or (II):wherein:X is CH or N;Y is CH or N;Ri is H, halo, or perhaloalkyl;R2 is H or halo; R3 is halo or alkoxy;R4 is -NH-alkyl, -NH-substituted alkyl, or -N-heterocycle;R7is H or -CH2N(R9)2;Rs is -CH2N(R9)2; andeach R9 is alkyl or wherein two R9 together are alkylene and together with the nitrogen atom to which they are attached form a nitrogen-containing heterocycle; or a pharmaceutically acceptable salt thereof; and wherein when the compound has a structure of Formula (I) and X and Y are each CH, Ri is H, and R2 is Cl, R?is not methoxy; and wherein when the compound has a structure of Formula (II) and X is CH, Ri is H, and R2 is Cl, R3 is not methoxy.

2. The compound of claim 1, wherein the compound has a structure of Formula (I).

3. The compound of claim 2, wherein X is CH, optionally wherein X is CH and Y is N.

4. The compound of claim 2, wherein Ri and R3 are each Cl.

5. The compound of claim 2, wherein Ri is halo or perfluoroalkyl, optionally Cl or CF3 and R2 is H.

6. The compound of claim 2, wherein R4 is -NHCH(Rs)-L-N(R6)2 or -NHCH(Rs)- L-C-(NHRe)2, wherein Rs is alkyl, optionally methyl, L is alkylene, optionally propylene, and Re is alkyl, optionally ethyl or methyl.

7. The compound of claim 2, wherein the compound is selected from the groupor a pharmaceutically acceptable salt thereof.

8. The compound of claim 1, wherein the compound has a structure of Formula (II).

9. The compound of claim 8, wherein X is N and Y is CH.

10. The compound of claim 8, wherein Ri is halo or perfluoroalkyl, optionally wherein Ri is Cl, F, or CF3.

11. The compound of claim 8, wherein R3 is halo, optionally Cl.

12. The compound of claim 8, wherein Rs is -CHN(R9)2, wherein the two R9 together are butylene, optionally wherein R7 is H or -CHN(R9)2, wherein the two R9 together are butylene.

13. The compound of claim 8, wherein the compound is selected from the group consisting of:or a pharmaceutically acceptable salt thereof.

14. A pharmaceutical composition comprising a compound of any one of claims 1- 13 and a pharmaceutically acceptable carrier.

15. A method of treating a viral infection or a disease caused by a viral infection in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound of any one of claims 1-13 or a pharmaceutical composition of claim 14.

16. The method of claim 15, wherein the viral infection is a coronavirus infection.

17. The method of claim 15, wherein the coronavirus infection is an infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

18. The method of claim 15, wherein the compound has a 50% inhibitory concentration (IC50) against SARS-CoV-2 that is less than about 2.0 micromolar (pM), optionally less than about 1.0 pM.

19. The method of claim 17 or claim 18, wherein the compound has a 50% cytotoxicity concentration (CC50) that is greater than about 4.0 pM.

20. The method of any one of claims 17-19 wherein the compound has a selectivity index (SI) of about 10 or more.

21. The method of any one of claims 15-20, wherein the compound is selected from the group consisting of:or a pharmaceutically acceptable salt thereof.

22. Use of a compound of any one of claims 1-13 in the preparation of a medicament for treating a viral infection or a disease caused by a viral infection, optionally wherein the viral infection is a coronavirus infection, further optionally wherein the coronavirus infection is a SARS-CoV-2 infection.

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