3cpro inhibitors and methods thereof

Abstract

The disclosure relates to 3Cpro inhibitors. The 3Cpro inhibitor is a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof. The disclosure also relates to methods of treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV) in a subject in need thereof by using compound of Formula (I).

Description

[0001]

[0002] 3Cpro Inhibitors and Methods Thereof

[0003] Technical Field

[0004] The present invention relates, in general terms, to 3Cpro inhibitors and the methods of treatment thereof.

[0005] Background

[0006] Picornaviridae family consisting of genus Enterovirus (EV) include pathogens infecting humans. They are known to cause respiratory diseases, encephalitis, myocarditis and hand foot and mouth disease (HFMD). Enterovirus genus contains 12 species (EV A-L) and three are Rhinovirus species (RV A-C). Enteroviruses A & B have caused extremely large-scale, periodic epidemics in children, particularly in Asia-Pacific countries. From 2008 to 2015, China has observed EV-A71 outbreaks, which resulted in 12 million cases, including 123,261 severe cases and 3,322 deaths. From 2014 to 2015, EV-A71 outbreaks were observed in Thailand and Vietnam, resulting in more than 120,000 cases.

[0007] Large outbreaks of EV-D68 have emerged over recent years, and is increasingly becoming a serious global health concern. EV-D68 infection leads to severe lower respiratory infections and are associated with acute flaccid myelitis (AFM). Recent strains of EV-D68 has increased virulence. In 2014, US reported an outbreak leading to 1200 hospital admissions, 120 cases of AFM and 12 deaths. Since 2014, EV-D68 infections and EV-D68 assoc. AFM cases increased in US and Europe. In 2016 and 2018, 153 and 237 AFM cases are reported in US, respectively.

[0008] Human rhinovirus (HRV) is responsible for more than one-half of cold-like illnesses and cost more than $40 billion annually in the US. HRV infections leads to exacerbations of asthma and chronic obstructive pulmonary disease (COPD). HRV is also traditionally associated with upper respiratory tract infection (URTI), and also causes lower respiratory tract disease (LRTD), including severe pneumonia in immunocompetent individuals, patients with asthma, COPD, infants, children, elderly and immunocompromised. It is estimated that in US, about 4.8 million COPD patients and about 5 million asthma patients have their conditions exacerbated by HRV per year.

[0009] Enteroviruses are single-stranded, positive-sense RNA of approximately 7,500 bases in length. The enterovirus genome consists of a single polyprotein which is processed through a series of primary and secondary proteolytic cleavages by the virus-encoded proteases, 2Apro and 3Cpro, to give rise to structural and nonstructural viral proteins. It has been demonstrated that inhibiting the proteolytic processing of virus polyproteins via inhibition of 3Cpro is able to block viral replication effectively.

[0010] Rupintrivir was previously tested as a drug to treat enterovirus related diseases. However, it was discontinued in phase II as no clinical benefit was found.

[0011] To date, no approved specific antiviral therapy for diseases caused by these viruses is available. Hence, there is an urgent need to develop broad-spectrum novel compounds against viral targets that are conserved within this virus family and are crucial for virus replication. There is a lack of pharmaceutical compounds which can effectively inhibit 3Cpro, or specifically inhibit 3Cpro.

[0012] It would be desirable to overcome or ameliorate at least one of the above-described problems.

[0013] Summary

[0014] The present invention relates a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof: wherein R1is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted heteroaryl; R2is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl; R3is selected from H, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted heteroaryl; R4is selected from optionally substituted alkyl or optionally substituted cycloalkyl; R5, R6, R7and R8are independently selected from H or optionally substituted alkyl; or R4and R8are linked to form an optionally substituted heterocyclyl; n is an integer from 1 to 4; and m is an integer from 1 to 3.

[0015] In some embodiments, R1is selected from optionally substituted C2-C6 alkyl, optionally substituted spiro or fused cycloalkyl, or optionally substituted heteroaryl.

[0016] In some embodiments, R1is selected from

[0017] In some embodiments, R2is selected from optionally substituted C2-C6alkyl, optionally substituted C4-C8cycloalkyl, optionally substituted C4-C8aryl, optionally substituted C4- C8heteroaryl, optionally substituted (C4-C8)aryl(C1-C4)alkyl, or optionally substituted (C4-C8)heteroaryl(C1-C4)alkyl.

[0018] In some embodiments, R2is selected from

[0019] In some embodiments, R3is at a beta position relative to N.

[0020] In some embodiments, R3is selected from H, optionally substituted C1-C6alkyl, optionally substituted C3-C10 cycloalkyl or optionally substituted C4-C8aryl or optionally substituted C4-C8heteroaryl.

[0021] In some embodiments, R3is selected from H,

[0022] In some embodiments, R4is selected from optionally substituted C1-C6alkyl or optionally substituted C3-C6cycloalkyl.

[0023] In some embodiments, R4is selected from methyl, ethyl, propyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, or phenylmethyl.

[0024] In some embodiments, R5, R6, R7and R8are independently selected from H or C1-C6alkyl.

[0025] In some embodiments, n is an integer from 1 to 3.

[0026] In some embodiments, n is 2.

[0027] In some embodiments, m is 1 or 2.

[0028] In some embodiments, the compound is represented by Formula (la):

[0029] In some embodiments, the compound is represented by Formula (lb) or (Ic):

[0030] In some embodiments, the compound is selected from:

[0031]

[0032] In some embodiments, the compound is characterised by IC50 against Enterovirus of less than about 20 μM.

[0033] In some embodiments, the compound is characterised by IC50 against human Rhinovirus of less than about 20 μM.

[0034] In some embodiments, the compound is characterised by EC50 against Enterovirus of less than about 20 μM.

[0035] In some embodiments, the compound is characterised by EC50 against human Rhinovirus of less than about 20 μM.

[0036] The present invention relates to a method of treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV) in a subject in need thereof, comprising administering a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof to the subject.

[0037] The present invention relates to a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof for use in treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV).

[0038] The present invention relates to a use of a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof in the manufacture of a medicament for treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV).

[0039] In some embodiments, the disease or condition caused by EV and HRV is selected from poliomyelitis, nonspecific febrile, Bornholm disease, sepsis, aseptic meningitis, pericarditis, myocarditis, arrhythmias, heart failure, myocardial infarction, acute hemorrhagic conjunctivitis, herpangina, hand foot mouth disease, encephalitis, fever, muscle pain, sore throat, gastrointestinal distress / abdominal discomfort, headache, nausea, emesis, common cold, acute respiratory distress syndrome (ARDS), acute flaccid myelitis, viral-induced trigger and exacerbation of COPD and asthma, or hand foot mouth disease as well as its respective neurological and cardiac complications.

[0040] Detailed description

[0041] "Alkyl" refers to monovalent alkyl groups which may be straight chained or branched and preferably have from 1 to 10 carbon atoms or more preferably 1 to 6 carbon atoms. Examples of such alkyl groups include methyl, ethyl, n-propyl, / so-propyl, n-butyl, iso- butyl, n-hexyl, and the like.

[0042] "Aryl" refers to an unsaturated aromatic carbocyclic group having a single ring (eg. phenyl) or multiple condensed rings (eg. naphthyl or anthryl), preferably having from 6 to 14 carbon atoms. Examples of aryl groups include phenyl, naphthyl and the like.

[0043] "Heteroaryl" refers to a monovalent aromatic heterocyclic group which fulfils the Huckel criteria for aromaticity (ie. contains 4n + 2 n electrons) and preferably has from 2 to 10 carbon atoms and 1 to 4 heteroatoms selected from oxygen, nitrogen, selenium, and sulfur within the ring (and includes oxides of sulfur, selenium and nitrogen). Such heteroaryl groups can have a single ring (eg. pyridyl, pyrrolyl or N- oxides thereof or furyl) or multiple condensed rings (eg. indolizinyl, benzoimidazolyl, coumarinyl, quinolinyl, isoquinolinyl or benzothienyl).

[0044] Examples of heteroaryl groups include, but are not limited to, oxazole, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine, isoquinoline, quinoline, phthalazine, naphthylpyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, phenanthroline, isothiazole, phenazine, isoxazole, isothiazole, phenoxazine, phenothiazine, thiazole, thiadiazoles, oxadiazole, oxatriazole, tetrazole, thiophene, benzo[b]thiophene, triazole, imidazopyridine and the like.

[0045] "Cycloalkyl" refers to cyclic alkyl groups having a single cyclic ring or multiple condensed rings, preferably incorporating 3 to 11 carbon atoms. Such cycloalkyl groups include, by way of example, single ring structures such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, and the like, or multiple ring structures such as adamantanyl, indanyl, 1,2,3,4-tetrahydronapthalenyl and the like.

[0046] "Cycloalkenyl" refers to cyclic alkenyl groups having a single cyclic ring or multiple condensed rings, and at least one point of internal unsaturation, preferably incorporating 4 to 11 carbon atoms. Examples of suitable cycloalkenyl groups include, for instance, cyclobut-2-enyl, cyclopent-3-enyl, cyclohex-4-enyl, cyclooct- 3-enyl, indenyl and the like.

[0047] "Heterocyclyl" refers to a monovalent saturated or unsaturated group having a single ring or multiple condensed rings, preferably from 1 to 8 carbon atoms and from 1 to 4 hetero atoms selected from nitrogen, sulfur, oxygen, selenium or phosphorous within the ring. The most preferred heteroatom is nitrogen. It will be understood that where, for instance, R2or R' is an optionally substituted heterocyclyl which has one or more ring heteroatoms, the heterocyclyl group can be connected to the core molecule of the compounds of the present invention, through a C-C or C-heteroatom bond, in particular a C-N bond.

[0048] Examples of heterocyclyl and heteroaryl groups include, but are not limited to, oxazole, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine, quinolizine, isoquinoline, quinoline, phthalazine, naphthylpyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, phenanthroline, isothiazole, phenazine, isoxazole, isothiazole, phenoxazine, phenothiazine, imidazolidine, imidazoline, piperidine, piperazine, indoline, phthalimide, 1,2, 3, 4-tetra hydroisoquinoline, 4,5,6,7-tetrahydrobenzo[b]thiophene, thiazole, thiadiazoles, oxadiazole, oxatriazole, tetrazole, thiazolidine, thiophene, benzo[b]thiophene, morpholino, piperidinyl, pyrrolidine, tetra hydrofuranyl, triazole, and the like.

[0049] In this specification "optionally substituted" is taken to mean that a group may or may not be further substituted or fused (so as to form a condensed polycyclic group) with one or more groups selected from hydroxyl, acyl, alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy, amino, aminoacyl, thio, arylalkyl, arylalkoxy, aryl, aryloxy, carboxyl, acylamino, cyano, halogen, nitro, phosphono, sulfo, phosphorylamino, phosphinyl, heteroaryl, heteroarylalkyl, heteroaryloxy, heterocyclyl, heterocyclylalkyl, heterocyclyloxy, oxyacyl, oxime, oxime ether, hydrazone, oxyacylamino, oxysulfonylamino, aminoacyloxy, trihalomethyl, trialkylsilyl, pentafluoroethyl, trifluoromethoxy, difluoromethoxy, trifluoromethanethio, trifluoroethenyl, mono- and di-alkylamino, mono-and di-(substituted alkyl)amino, mono- and di-arylamino, mono- and di-heteroarylamino, mono- and di-heterocyclyl amino, and unsymmetric di-substituted amines having different substituents selected from alkyl, aryl, heteroaryl and heterocyclyl, and the like, and may also include a bond to a solid support material, (for example, substituted onto a polymer resin). For instance, an "optionally substituted amino" group may include amino acid and peptide residues.

[0050] "Isomer" includes especially optical isomers (for example essentially pure enantiomers, essentially pure diastereomers, and mixtures thereof) as well as conformation isomers (i.e. isomers that differ only in their angles of at least one chemical bond), position isomers (particularly tautomers), and geometric isomers (e.g. cis-trans isomers).

[0051] Compounds described herein can comprise one or more asymmetric centers, and thus can exist in various isomeric forms, e.g., enantiomers and / or diastereomers. For example, the compounds described herein can be in the form of an individual enantiomer, diastereomer or geometric isomer, or can be in the form of a mixture of stereoisomers, including racemic mixtures and mixtures enriched in one or more stereoisomer. Isomers can be isolated from mixtures by methods known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts; or preferred isomers can be prepared by asymmetric syntheses. The invention additionally encompasses compounds described herein as individual isomers substantially free of other isomers, and alternatively, as mixtures of various isomers. "Optically-enriched," as used herein, means that the compound is made up of a significantly greater proportion of one enantiomer. In certain embodiments the compound of the present invention is made up of at least about 90% by weight of a preferred enantiomer. In other embodiments the compound is made up of at least about 95%, 98%, or 99% by weight of a preferred enantiomer. Preferred enantiomers may be isolated from racemic mixtures by any method known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts or prepared by asymmetric syntheses. See, for example, Jacques et al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen et al., Tetrahedron 33:2725 (1977); Eliel, Stereochemistry of Carbon Compounds (McGraw-Hill, NY, 1962); and Wilen, Tables of Resolving Agents and Optical Resolutions p. 268 (E.L. Eliel, Ed., Univ, of Notre Dame Press, Notre Dame, IN 1972).

[0052] The present disclosure is predicated on the understanding that 3Cpro is highly conserved among Enteroviruses (EV) and human Rhinovirus (HRV). The 3Cpro is distinguished from most other proteases by the fact that it has a cysteine nucleophile but with a chymotrypsin-like serine protease folding. This unique protein structure together with its essential role in viral replication made the 3Cpro an excellent target for antiviral intervention. In this regard, it is believed that broad spectrum 3Cpro inhibitors may be designed. The present disclosure concerns inhibitors of chymotrypsin-related protease (3Cpro). The compounds demonstrate inhibitory activity against EV and HRV.

[0053] The compounds of the present invention may be used as 3Cpro inhibitors, which targets HRV / EV virus. This is distinguished from 3CLpro / main protease (C30 endopeptidase or 3-chymotrypsin-like protease) inhibitors, which targets SARS-CoV-2 virus. 3CLpro has a different protein sequence compared to 3Cpro, and accordingly different active sites. Further, in some embodiments, the compounds of the present disclosure (such as example 6) only targets 3Cpro and not 3CLpro.

[0054] Accordingly, the present disclosure concerns a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof:

[0055] wherein R1is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted heteroaryl; R2is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl; R3is selected from H, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted heteroaryl R4is selected from optionally substituted alkyl or optionally substituted cycloalkyl; R5, R6, R7and R8are independently selected from H or optionally substituted alkyl; or R4and Rs are linked to form an optionally substituted heterocyclyl; n is an integer from 1 to 4; and m is an integer from 1 to 3.

[0056] In some embodiments, R1is selected from optionally substituted C1-C6alkyl, optionally substituted C3-C9cycloalkyl, or optionally substituted heteroaryl. In some embodiments, R1is selected from optionally substituted C1-C6alkyl, optionally substituted C3-C9cycloalkyl, or optionally substituted N-heteroaryl. In some embodiments, R1is selected from optionally substituted C2-C6 alkyl optionally substituted spiro or fused cycloalkyl, or optionally substituted 5 membered N-heteroaryl. In some embodiments, R1is selected from tert-butyl, methylisoxazolyl, spiro[3.3]heptanyl, or bicycle[l.l.l]heptanyl. In some embodiments, R1is selected from:

[0057] In some embodiments, when R1 is optionally substituted heteroaryl, the heteroatom in the heteroaryl is not linked to the amide moiety.

[0058] In some embodiments, R2is selected from optionally substituted C1-C6alkyl, optionally substituted C4-C8cycloalkyl, optionally substituted C4-C8aryl, optionally substituted C4- C8heteroaryl, optionally substituted (C4-C8)aryl(C1-C4)alkyl, or optionally substituted (C4-C8)heteroaryl(C1-C4)alkyl. In other embodiments, R2is selected from optionally substituted C2-C6 alkyl, optionally substituted C4-C8cycloalkyl, optionally substituted phenyl, optionally substituted phenyl( C4-C8)alkyl, or optionally substituted heteroaryl(C1-C4)alkyl. In other embodiments, R2is selected from propyl or cyclopenta nyl. In other embodiments, R2is selected from:

[0059] In some embodiments, R3is connected to the N-heterocyclyl via a single bond. In other words, R3is not connected to the N-heterocyclyl via a spiro or fused connection. In some embodiments, Rs is connected to the N-heterocyclyl via a spiro or fused connection.

[0060] In some embodiments, R3is at an alpha position relative to N. In some embodiments, R3is at a beta position relative to N.

[0061] In some embodiments, Rs is a lipophilic moiety. In other embodiments, Rs is selected from H, optionally substituted C1-C6alkyl, optionally substituted C3-C10 cycloalkyl or optionally substituted C6-C10aryl or optionally substituted C4-C8heteroaryl. In other embodiments, Rs is selected from H, optionally substituted C1-C6alkyl, optionally substituted C3-C10 cycloalkyl, optionally substituted phenyl or optionally substituted C4- Cs heteroaryl. In other embodiments, Rs is selected from H, methyl, ethyl, propyl, cyclopentyl, cyclopropyl, dimethylcyclopropyl phenyl or pyrindinyl.

[0062] In some embodiments, R3is selected from: H

[0063] In some embodiments, Rs is selected from fused cyclopropyl, fused dimethylcyclopropyl, fused cyclopentyl, fused phenyl, spiro cyclopropyl, and spiro cyclopentyl.

[0064] In some embodiments, R4is selected from optionally substituted C1-C6alkyl or optionally substituted C3-C6cycloalkyl. In other embodiments, R4is selected from methyl, ethyl, propyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, or phenylmethyl.

[0065] In some embodiments, R5, R6, R7and R8are independently selected from H or C1-C6alkyl. In some embodiments, R5, R6, R7and R8are independently selected from H, methyl, ethyl or propyl. In some embodiments, R5, R6, R7and R8are independently H.

[0066] In some embodiments, R4and R8form an optionally substituted heterocyclyl. In other embodiments, R4and Rs are linked to form an optionally substituted C3-C6heterocyclyl.

[0067] In some embodiments, n is an integer from 1 to 3. In other embodiments, n is 2.

[0068] In some embodiments, m is an integer from 1 to 2.

[0069] In some embodiments, the compound is represented by Formula (I1), (I") or (I'"):

[0070]

[0071] In some embodiments, the compound is represented by Formula (la):

[0072]

[0073] In some embodiments, the compound is represented by Formula (la1), (la"), (la1"), (Ia'v), (Iav) or (Iavl):

[0074]

[0075] In some embodiments, the compound is represented by Formula (lb) :

[0076] In some embodiments, the compound is represented by Formula (lb'), (lb"), (lb'"), (Ib,v), (Ibv) or (Ibvl):

[0077]

[0078] In some embodiments, the compound is represented by Formula (Ic):

[0079] In some embodiments, the compound is represented by Formula (Ic1), (Ic"),(Ic'"),

[0080] (Ic'v), (Icv) or (Icvl):

[0081]

[0082] It was found that the 'S' stereocentre at R2shows consistently better inhibitory activity against HRV 3CPro enzyme. This is also in line with computational modelling (docking) study of these compounds, which is further corroborated with Structure Activity Relationship (SAR) analysis.

[0083] In some embodiments, the compound is selected from:

[0084]

[0085]

[0086]

[0087] In some embodiments, the compound is selected from:

[0088]

[0089] When R3is connected to the N-heterocyclyl via a spiro or fused connection, R3may be selected from

[0090] In some embodiments, the compound of Formula (I) is selected from:

[0091]

[0092] In some embodiments, the compound of Formula (I) is selected from:

[0093]

[0094] The IC50 is the concentration of an inhibitor where the response (or binding) is reduced by half. In some embodiments, the compound is characterised by IC50 against Enterovirus and / or human Rhinovirus of less than about 20 μM. In other embodiments, the IC50 is less than about 18 μM, about 16 μM, about 15 μM, about 14 μM, about 12 μM, about 10 μM, about 8 μM, about 6 μM, about 5 μM, about 2 μM, or about 1 μM. In other embodiments, the IC50 is less than about 900 nM, about 800 nM, about 700 nM, about 600 nM, about 500 nM, about 400 nM, about 300 nM, about 200 nM, or about 100 nM . In other embodiments, the IC50 is about 1 nM to about 20 μM, about 10 nM to about 20 μM, about 20 nM to about 20 μM, about 30 nM to about 20 μM, about 40 nM to about 20 μM, about 50 nM to about 20 μM, about 60 nM to about 20 μM, about 70 nM to about 20 μM, about 80 nM to about 20 μM, about 90 nM to about 20 μM, about 100 nM to about 20 μM. In other embodiments, the IC50 is about 1 nM to about 18 μM, about 1 nM to about 16 μM, about 1 nM to about 14 μM, about 1 nM to about 12 μM, about 1 nM to about 10 μM, about 1 nM to about 8 μM, about 1 nM to about 6 μM, about 1 nM to about 4 μM, about 1 nM to about 2 μM, about 1 nM to about 1 μM, about 1 nM to about 900 nM, about 1 nM to about 800 nM, about 1 nM to about 700 nM, about 1 nM to about 600 nM, about 1 nM to about 500 nM, about 1 nM to about 400 nM, about 1 nM to about 300 nM, about 1 nM to about 200 nM, or about 1 nM to about 100 nM.

[0095] The EC50 is the concentration of a drug that gives half-maximal response. In some embodiments, the compound is characterised by EC50 against Enterovirus and / or human Rhinovirus of less than about 20 μM. In other embodiments, the EC50 is less than about 18 μM, about 16 μM, about 15 μM, about 14 μM, about 12 μM, about 10 μM, about 8 μM, about 6 μM, about 5 μM, about 2 μM, or about 1 μM. In other embodiments, the EC50 is less than about 900 nM, about 800 nM, about 700 nM, about 600 nM, about 500 nM, about 400 nM, about 300 nM, about 200 nM, or about 100 nM. In other embodiments, the EC50 is about 1 nM to about 20 μM, about 10 nM to about 20 μM, abopt 20 nM to about 20 μM, about 30 nM to about 20 μM, about 40 nM to about 20 μM, about 50 nM to about 20 μM, about 60 nM to about 20 μM, about 70 nM to about 20 μM, about 80 nM to about 20 μM, about 90 nM to about 20 μM, abopt 100 nM to about 20 μM. In other embodiments, the EC50 is about 1 nM to about 18 μM, about 1 nM to about 16 μM, about 1 nM to about 14 μM, about 1 nM to about 12 μM, about 1 nM to about 10 μM, about 1 nM to about 8 μM, about 1 nM to about 6 μM, about 1 nM to about 4 μM, about 1 nM to about 2 μM, about 1 nM to about 1 μM, about 1 nM to about 900 nM, about 1 nM to about 800 nM, about 1 nM to about 700 nM, about 1 nM to about 600 nM, about 1 nM to about 500 nM, about 1 nM to about 400 nM, about 1 nM to about 300 nM, about 1 nM to about 200 nM, or about 1 nM to about 100 nM.

[0096] The present disclosure also concerns a pharmaceutical composition comprising a compound of Formula (I), and optionally an excipient.

[0097] The present disclosure also concerns a method of synthesising a compound of Formula (I). The compound may be synthesised via solid phase synthesis.

[0098] The present disclosure also concerns a method of treating a disease or condition associated with 3Cpro in a subject in need thereof, comprising administering a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof to the subject. The disease or condition may be characterised by a presence of 3Cpro, or by an upregulation of 3Cpro.

[0099] The present disclosure also concerns a method of treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV) in a subject in need thereof, comprising administering a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof to the subject.

[0100] The present disclosure also concerns a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof for use in treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV).

[0101] The present disclosure also concerns use of a compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof in the manufacture of a medicament for treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV).

[0102] As mentioned, the compounds of the present disclosure are 3Cpro inhibitors. The compounds shows good to excellent activity when tested against human Rhinovirus (HRV-14), Enterovirus 68 (EV-D68), Enterovirus 71 (EV-A71) and coxsackievirus B3 (CV-B3). In contrast, when tested against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the activity is significantly lower.

[0103] In some embodiments, the disease or condition caused by Enterovirus (EV) is selected from poliomyelitis, nonspecific febrile, Bornholm disease, sepsis, aseptic meningitis, pericarditis, myocarditis, arrhythmias, heart failure, myocardial infarction, acute hemorrhagic conjunctivitis, herpangina, hand foot mouth disease, encephalitis, fever, muscle pain, sore throat, gastrointestinal distress / abdominal discomfort, headache, nausea, emesis, common cold, acute respiratory distress syndrome (ARDS), acute flaccid myelitis, viral-induced trigger and exacerbation of COPD and asthma, or hand foot mouth disease as well as its respective neurological and cardiac complications.

[0104] In some embodiments, the disease or condition caused by human Rhinovirus (HRV) is common cold.

[0105] In some embodiments, Enterovirus is coxsackievirus. The disease or condition may be hand, foot, and mouth disease (HFMD), muscle infection, heart infection, and meningitis.

[0106] The compound of the invention can be administered to a subject as a pharmaceutically acceptable salt thereof. Suitable pharmaceutically acceptable salts include, but are not limited to salts of pharmaceutically acceptable inorganic acids such as hydrochloric, sulphuric, phosphoric, nitric, carbonic, boric, sulfamic, and hydrobromic acids, or salts of pharmaceutically acceptable organic acids such as acetic, propionic, butyric, tartaric, maleic, hydroxymaleic, fumaric, maleic, citric, lactic, mucic, gluconic, benzoic, succinic, oxalic, phenylacetic, methanesulphonic, toluenesulphonic, benezenesulphonic, salicyclic sulphanilic, aspartic, glutamic, edetic, stearic, palmitic, oleic, lauric, pantothenic, tannic, ascorbic and valeric acids.

[0107] Base salts include, but are not limited to, those formed with pharmaceutically acceptable cations, such as sodium, potassium, lithium, calcium, magnesium, ammonium and alkylammonium. In particular, the present invention includes within its scope cationic salts eg sodium or potassium salts, or alkyl esters (eg methyl, ethyl) of the phosphate group.

[0108] Basic nitrogen-containing groups may be quarternised with such agents as lower alkyl halide, such as methyl, ethyl, propyl, and butyl chlorides, bromides and iodides; dialkyl sulfates like dimethyl and diethyl sulfate; and others.

[0109] It will be appreciated that any compound that is a prodrug of the compound of formula (I) is also within the scope and spirit of the invention. Thus the compound of the invention can be administered to a subject in the form of a pharmaceutically acceptable pro-drug. The term "pro-drug" is used in its broadest sense and encompasses those derivatives that are converted in vivo to the compound of the invention. Such derivatives would readily occur to those skilled in the art. Other texts which generally describe prodrugs (and the preparation thereof) include: Design of Prodrugs, 1985, H. Bundgaard (Elsevier); The Practice of Medicinal Chemistry, 1996, Camille G. Wermuth et al., Chapter 31 (Academic Press); and A Textbook of Drug Design and Development, 1991, Bundgaard et al., Chapter 5, (Harwood Academic Publishers). For example, a hydrogen at N may be replaced by a group selected from 9-Fluorenylmethyl carbamate (Fmoc), t-Butyl carbamate (Boc), Benzyl carbamate, acetamide, Trifluoroacetamide, Phthalimide, Benzylamine, Triphenylmethylamine, Benzylideneamine, and p- toluenesulfonamide (Tos).

[0110] The compound of the invention may be in crystalline form either as the free compound or as a solvate (e.g. hydrate) and it is intended that both forms are within the scope of the present invention. Methods of solvation are generally known within the art.

[0111] The compound of the invention, or a pharmaceutically acceptable salt, solvate or prodrug thereof is administered to the patient in a therapeutically effective amount. As used herein, a therapeutically effective amount is intended to include at least partially attaining the desired effect, or delaying the onset of, or inhibiting the progression of, or halting or reversing altogether the onset or progression of the disease or condition caused by Enterovirus (EV) and human Rhinovirus (HRV).

[0112] The term "therapeutic effect" refers to some extent of relief of one or more of the symptoms of a disease or condition or its associated pathology.

[0113] As used herein, the term "effective amount" relates to an amount of compound which, when administered according to a desired dosing regimen, provides the desired therapeutic activity; i.e. prolonging the survivability of the patient with such a disease or condition, reducing one or more signs or symptoms of the disease or condition, preventing or delaying, and the like beyond that expected in the absence of such treatment. Dosing may occur at intervals of minutes, hours, days, weeks, months or years or continuously over any one of these periods. Suitable dosages may lie within the range of about 0.1 ng per kg of body weight to 1 g per kg of body weight per dosage, such as is in the range of 1 mg to 1 g per kg of body weight per dosage. In one embodiment, the dosage may be in the range of 1 mg to 500 mg per kg of body weight per dosage. In another embodiment, the dosage may be in the range of 1 mg to 250 mg per kg of body weight per dosage. In yet another embodiment, the dosage may be in the range of 1 mg to 100 mg per kg of body weight per dosage, such as up to 50 mg per body weight per dosage.

[0114] Suitable dosage amounts and dosing regimens can be determined by the attending physician and may depend on the severity of the condition as well as the general age, health and weight of the patient to be treated.

[0115] The compound of the invention may be administered in a single dose or a series of doses. While it is possible for the active ingredient to be administered alone, it is preferable to present it as a composition, preferably as a pharmaceutical composition. The formulation of such compositions is well known to those skilled in the art. The composition may contain any suitable carriers, diluents or excipients. These include all conventional solvents, dispersion media, fillers, solid carriers, coatings, antifungal and antibacterial agents, dermal penetration agents, surfactants, isotonic and absorption agents and the like. It will be understood that the compositions of the invention may also include other supplementary physiologically active agents.

[0116] The carrier must be pharmaceutically "acceptable" in the sense of being compatible with the other ingredients of the composition and not injurious to the patient. The compositions may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the active ingredient with the carrier which constitutes one or more accessory ingredients. In general, the compositions are prepared by uniformly and intimately bringing into association the active ingredient with liquid carriers or finely divided solid carriers or both, and then if necessary shaping the product.

[0117] Injectables for such use can be prepared in conventional forms, either as a liquid solution or suspension or in a solid form suitable for preparation as a solution or suspension in a liquid prior to injection, or as an emulsion. Carriers can include, for example, water, saline (e.g., normal saline (NS), phosphate-buffered saline (PBS), balanced saline solution (BSS)), sodium lactate Ringer's solution, dextrose, glycerol, ethanol, and the like; and if desired, minor amounts of auxiliary substances, such as wetting or emulsifying agents, buffers, and the like can be added. Proper fluidity can be maintained, for example, by using a coating such as lecithin, by maintaining the required particle size in the case of dispersion and by using surfactants.

[0118] A person skilled in the art will appreciate that other means for injecting and / or administering the compound, composition or combinations to the vitreous of the eye can also be used. These other means can include, for example, intravitreal medical delivery devices. These devices and methods can include, for example, intravitreal medicine delivery devices, and biodegradable polymer delivery members that are inserted in the eye for long term delivery of medicaments. These devices and methods can further include transscleral delivery devices.

[0119] Other modes of administration including topical or intravenous administration may also be possible. For example, solutions or suspensions of the compound, composition or combinations of the invention may be formulated as eye drops, or as a membranous ocular patch, which is applied directly to the surface of the eye. Topical application typically involves administering the compound of the invention in an amount between 0.1 ng and 50 mg.

[0120] The compound or composition of the invention may also be suitable for intravenous administration. For example, a compound of formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof may be administered intravenously at a dose of up to 50 mg / m2.

[0121] The compound or composition of the invention may also be suitable for oral administration and may be presented as discrete units such as capsules, sachets or tablets each containing a predetermined amount of the active ingredient; as a powder or granules; as a solution or a suspension in an aqueous or non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion. The active ingredient may also be presented as a bolus, electuary or paste. In another embodiment, the compound of formula (I) or a pharmaceutically acceptable salt, solvate or prodrug is orally administerable.

[0122] A tablet may be made by compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active ingredient in a free-flowing form such as a powder or granules, optionally mixed with a binder (e.g inert diluent, preservative disintegrant (e.g. sodium starch glycolate, cross-linked polyvinyl pyrrolidone, cross-linked sodium carboxymethyl cellulose) surface-active or dispersing agent. Moulded tablets may be made by moulding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent. The tablets may optionally be coated or scored and may be formulated so as to provide slow or controlled release of the active ingredient therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile. Tablets may optionally be provided with an enteric coating, to provide release in parts of the gut other than the stomach.

[0123] The compound or composition of the invention may be suitable for topical administration in the mouth including lozenges comprising the active ingredient in a flavoured base, usually sucrose and acacia or tragacanth gum; pastilles comprising the active ingredient in an inert basis such as gelatine and glycerin, or sucrose and acacia gum; and mouthwashes comprising the active ingredient in a suitable liquid carrier.

[0124] The compound or composition of the invention may be suitable for topical administration to the skin may comprise the compounds dissolved or suspended in any suitable carrier or base and may be in the form of lotions, gel, creams, pastes, ointments and the like. Suitable carriers include mineral oil, propylene glycol, polyoxyethylene, polyoxypropylene, emulsifying wax, sorbitan monostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and water. Transdermal patches may also be used to administer the compounds of the invention.

[0125] The compound or composition of the invention may be suitable for parenteral administration include aqueous and non-aqueous isotonic sterile injection solutions which may contain anti-oxidants, buffers, bactericides and solutes which render the compound, composition or combination isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The compound or composition may be presented in unitdose or multi-dose sealed containers, for example, ampoules and vials, and may be stored in a freeze-dried (lyophilised) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules and tablets of the kind previously described.

[0126] Preferred unit dosage composition are those containing a daily dose or unit, daily subdose, as herein above described, or an appropriate fraction thereof, of the active ingredient.

[0127] It should be understood that in addition to the active ingredients particularly mentioned above, the composition of this invention may include other agents conventional in the art having regard to the type of composition or combination in question, for example, those suitable for oral administration may include such further agents as binders, sweeteners, thickeners, flavouring agents disintegrating agents, coating agents, preservatives, lubricants and / or time delay agents. Suitable sweeteners include sucrose, lactose, glucose, aspartame or saccharine. Suitable disintegrating agents include cornstarch, methylcellulose, polyvinylpyrrolidone, xanthan gum, bentonite, alginic acid or agar. Suitable flavouring agents include peppermint oil, oil of Wintergreen, cherry, orange or raspberry flavouring. Suitable coating agents include polymers or copolymers of acrylic acid and / or methacrylic acid and / or their esters, waxes, fatty alcohols, zein, shellac or gluten. Suitable preservatives include sodium benzoate, vitamin E, alpha-tocopherol, ascorbic acid, methyl paraben, propyl paraben or sodium bisulphite. Suitable lubricants include magnesium stearate, stearic acid, sodium oleate, sodium chloride or talc. Suitable time delay agents include glyceryl monostearate or glyceryl distearate.

[0128] Examples

[0129] In general, the compounds as disclosed herein may be synthesised by Solid-Phase- Synthesis (SPS)-flow platform or conventional solution batch synthesis.

[0130] As an example, synthesis of Example 11 by Solid-Phase Synthesis flow platform is depicted below:

[0131] 98% yield 90% yield

[0132] 100 grams scale

[0133] Synthesis of 4-((tert-butyldimethylsilyl)oxy)benzonitrile: 4-hydroxybenzonitrile was dissolved in DCM, and then TBDMSCI (1.2 equivalent) and EtsN (2 equivalent) were added. The resulting mixture was stirred at 20 °C for 24 h and HzO was added. The above solution was washed with water three times. The organic phase was separated, dried with anhydrous sodium sulfate. The organic solvent was evaporated under reduced pressure to give the crude product 4-((tert-butyldimethylsilyl)oxy)benzonitrile as white solid which can be used for the next step without further purification.

[0134] Synthesis of (4-hydroxyphenyl)(4-methoxyphenyl)methanone: 4-((tert- butyldimethylsilyl)oxy)benzonitrile was dissolved in dry THF, and then (4- methoxyphenyl)magnesium bromide (1.3 equivalent) was added. The resulting mixture was stirred at 80 °C for 12 h and 6 M HCI was added to the reaction solution until pH = 5. The resulting solution was further stirred at 80 °C for 4 h, when the reaction temperature returns to room temperature ethyl acetate was added. The organic phase was separated, dried with anhydrous sodium sulfate. The organic solvent was evaporated under reduced pressure to give the crude product. After recrystallization with hexane and ethyl acetate to give the pure product.

[0135] Scheme for the Wang Resin modification

[0136] Synthesis of brominated Wang resin: Wang resin (loading: 1.0-1.2 mmol / g) was dissolved in DCM, and then PBrs (3.6 mmol, 3 equivalent) was added. The resulting mixture was stirred at 20 °C for 3 h, and the liquid is subsequently removed via filtration. The resin is then washed three times with DCM and after dried promptly utilized for the next step.

[0137] Synthesis of R-l: brominated Wang resin was dissolved in DMF, and then (4- hydroxyphenyl)(4-methoxyphenyl)methanone (2.5 equivalent) and CS2CO3 (3 equivalent) were added. The resulting mixture was stirred at 80 °C for 12 h, and H2O was added. The liquid is subsequently removed via filtration, the resin is then washed three times with CH3OH and DCM. After further dry under reduced pressure we can get R-l (loading: 0.7-.075 mmol / g). (Note: the loading was determined by the NMR with 1,3,5-trimethoxybenzene as internal standard).

[0138] Synthesis of R-2: R-l (10 g) was dissolved in dry THF, and then LiBH4 in THF (2 M, lOmL) was added. The resulting mixture was stirred at 20°C for 24 h, and CH3OH / H2O (1 : 1) was added. The liquid is subsequently removed via filtration, the resin is then washed three times with CH3OH and DCM. After further dry under reduced pressure we can get R-2.

[0139] Step 1-attachment of the starting compound to the resin R-2:

[0140] R-2 (1.0 g, 0.5 mmol / g) was loaded to the column reactor. Subsequently, 2.5 g of Compound 2, along with 100 pL of H2SO4, were dissolved in 25 mL of acetic acid and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 20 hours. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-3 resin was sequentially washed with 100 mL of MeOH and 100 mL of DMF, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0141] Step 2-deprotective reaction:

[0142] A mixture of 5 mL piperidine and 15 mL DMF was introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 20 minutes. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-4 resin was washed with 100 mL of DMF, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0143] Step 3-amide coupling reaction: o-Amino acid (5 equiv, 2.5 mmol), EDCI (6 equiv, 3 mmol) and DMAP (1 mmol) were dissolved in 20 mL of DCM and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 2 hours. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-5' resin was washed with 100 mL of DCM, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0144] Step 4-reduction reaction:

[0145] LiBF (2 M in THF, 2 mL) was dissolved in 20 mL of THF and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 2 hours. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-6' resin was sequentially washed with 100 mL of MeOH and 100 mL of DMF, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0146] Step 5-oxidation reaction:

[0147] DMP (1 g) was dissolved in 20 mL of DMF and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 4 hours. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-7' resin was sequentially washed with 100 mL of DMF and 100 mL of DCM, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0148] Step 6-oasserini reaction:

[0149] 2-isocyanopropane (5 equiv, 2.5 mmol) and benzoic acid (5 equiv, 2.5 mmol) were dissolved in 20 mL of DCM and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 6 hours. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-8’ resin was washed with 100 mL of DMF, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0150] Step 7-deprotective reaction:

[0151] A mixture of 5 mL piperidine and 15 mL DMF was introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 20 minutes. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-9' resin was washed with 100 mL of DMF, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0152] Step 8-amide coupling reaction: o-Amino acid (5 equiv, 2.5 mmol), HATU (6 equiv, 3 mmol), HOBt (1 mmol) and DIPEA (10 equiv, 5 mmol) were dissolved in 20 mL of DMF and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 miymin) for a duration of 6 hours.

[0153] Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R- 10' resin was washed withlOO mL of DMF, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0154] Step 9-deprotective reaction:

[0155] A mixture of 5 mL piperidine and 15 mL DMF was introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 20 minutes. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-ll’ resin was washed with 100 mL of DMF, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0156] Step 10-amide coupling reaction: a-Amino acid (5 equiv, 2.5 mmol), EDCI (6 equiv, 3 mmol) and DMAP (1 mmol) were dissolved in 20 mL of DCM and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 2 hours. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-12' resin was washed with 100 mL of THF / CH3OH / H2O (2 / 1 / 1), the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0157] Step 11-hvdrolvsis reaction:

[0158] NaOH (1 g) was dissolved in 20 mL of THF / CH3OH / H2O (2 / 1 / 1) and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 1 hour. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R-13' resin was sequentially washed with 100 mL of CH3OH and 100 mL of DMF, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0159] Step 12-oxidation reaction:

[0160] DMP (1 g) was dissolved in 20 mL of DMF and stored in a reagent bottle. This resultant solution was then introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 4 hours. Thereafter, the reagent bottle was replaced with a washing solvent bottle, and the R- 14' resin was sequentially washed with 100 mL of DMF and 100 mL of DCM, the resultant washing solvent was passed through the column reactor and collected in waste bottles. Following this process, the resin was deemed ready for subsequent procedures.

[0161] Step 13-cleavaae:

[0162] DCM / TFA (1 / 1, 40 mL) was introduced into the column reactor and circulated back into the original reagent bottle by the pump (flow rate 5 mL / min) for a duration of 6 hours. Thereafter, wash the column reactor with DCM and collect the final product in the original reagent bottle. Then the solvent was evaporated and the crude product was purified on silica and eluted with a mixture of ethyl acetate and MeOH (20: 1) to give the product 11 in 27% yield over 13 steps.

[0163] As an example, synthesis of Example C8 by conventional solution batch synthesis is depicted below:

[0164]

[0165] Step 1. Experimental procedure for compound 2

[0166] To a solution of methyl (S)-2-((tert-butoxycarbonyl)amino)-3-((S)-2-oxopyrrolidin-3- yl)propanoate (25.0 g, 94.610 mmol, 1.0 eq.) in THF (150 mL) was added LiBH4 (5.7 g, 261.945 mmol, 3.00 eq.). The mixture was stirred at 25 °C for 12 h. The mixture was diluted with DCM (400 mL), wash with brine. The organic phase was dried over Na2SO4, filtered and concentrated in vacuo to afford compound 2 (21.0 g, 81.30 mmol, 93.11 % yield) as white solid.lH NMR (400 MHz, CDCH) 6 6.26 (s, 1H), 5.46 (d, J = 8.0 Hz, 1H), 3.72 (s, 1H), 3.66 - 3.60 (m, 2H), 3.40 - 3.33 (m, 2H), 2.54 -

[0167] 2.41 (m, 2H), 2.02 - 1.95 (m, 1H), 1.88 - 1.79 (m, 1H), 1.67 - 1.62 (m, 1H), 1.43 (s, 9H).

[0168] Step 2. Experimental procedure for compound 3

[0169] To a solution of tert-butyl ((S)-l-hydroxy-3-((S)-2-oxopyrrolidin-3-yl)propan-2- yl)carbamate (11.40 g, 44.13 mmol, 1.0 eq.) in ACN (100 mL) was added IBX (24.7 g, 88.262 mmol, 2.0 eq.) at 80 °C under N2. After stirring at room temperature for 1 h, the mixture was filtered and concentrated in vacuo to afford crude product, which was purified by flash column chromatography (0% ~ 7%MeOH in DCM) to afford compound 3 (7.20 g, 28.092 mmol, 63.65% yield) as white solid.JH NMR (400 MHz, CDCIs) 6 9.59 (s, 1H), 6.43 - 6.34 (m, 1H), 6.18 (d, J = 6.8 Hz, 1H), 4.21 (s, 1H), 3.39 - 3.36 (m, 2H), 2.54 - 2.45 (m, 2H), 1.98 - 1.89 (m, 2H), 1.48 (s, 10H).

[0170] Step 3. Experimental procedure for compound 5

[0171] To a solution of tert-butyl ((S)-l-oxo-3-((S)-2-oxopyrrolidin-3-yl)propan-2- yl)carbamate (1.0 g, 3.902 mmol, 1.0 eq.) and isocyanocyclopentane (408.3 mg, 4.292 mmol, 1.10 eq.) in DCM (10 mL) at 0 °C, acetic acid (344 mg, 5.73 mmol, 2.0 eq) was added and the mixture was stirred at 25 °C for 16 hrs. The mixture was purified by flash column chromatography (0%~6%MeOH in DCM) to afford compound 5 (1.40 g, 3.402 mmol, 87.17% yield) as white solid. MS Ca led . : 411.5, MS found: 312.51 [M + H+-100]+.

[0172] Step 4. Experimental procedure for compound 6

[0173] To a solution of (3S)-3-((tert-butoxycarbonyl)amino)-l-(cyclopentylamino)-l-oxo-4- ((S)-2-oxopyrrolidin-3-yl)butan-2-yl acetate (2.2 g, 5.346 mmol, 1.00 eq.) in MeOH (15.00 mL) at 0 °C, a solution of lithium hydroxide (384.9 mg, 16.038 mmol, 3.00 eq.) in H2O (5.00 mL) was added in dropwise. Then the mixture was stirred at room temperature for 2h. The reaction mixture was quenched by NH4CI (20 ml) and extracted with DCM (100 mLX4). The combined DCM was washed with brine (40 mL), dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography (eluting 0%~6%MeOH in DCM) to afford compound 6 (1.97 g, 99.75% yield) as white solid. MS Calcd. : 369.23, MS found: 270.43 [M-Boc+H+]+.

[0174] Step 5. Experimental procedure for compound 7

[0175] Tert-butyl ((2S)-4-(cyclopentylamino)-3-hydroxy-4-oxo-l-((S)-2-oxopyrrolidin-3- yl)butan-2-yl)carbamate (260.0 mg, 0.704 mmol, 1.00 eq.) was dissolved in dioxane

[0176] (2.00 mL), HCI (2.00 mL, 8.0 mmol) was added and stirred at room temperature for lh. The reaction was concentrated under reduced pressure to give (3S)-3-amino-N- cyclopentyl-2-hydroxy-4-((S)-2-oxopyrrolidin-3-yl)butanamide hydrochloride (215 mg, 100% yield, crude) as white solid. MS Calcd. : 269.36, MS found: 271.44 [M + H+]+.

[0177] Step 6. Experimental procedure for compound 9

[0178] 3S)-3-amino-N-cyclopentyl-2-hyd roxy-4-((S)-2-oxopyrrolidin-3-yl)butanamide hydrochloride (215.0 mg, 0.703 mmol, 1.00 eq.) and (2S)-l-[(2-methylpropan-2- yl)oxycarbonyl]piperidine-2-carboxylic acid (177.2 mg, 0.773 mmol, 1.10 eq.) were dissolved in DCM (5 mL) at 0 °C, DIPEA(DIEA, Hunig's base) (363.4 mg, 2.812 mmol, 4.00 eq.) was then added and the solution was allowed to stir at 0 °C for 5 min. HATU (400.8 mg, 1.054 mmol, 1.50 eq.) was added and the resultant solution was stirred at 0 °C for 2h. The reaction solution was concentrated under reduced pressure. This crude oil was then purified by chromatography on Silica gel (1-10%CH30H / CH2C12) to afford crude, which was purified by prep-HPLC to give tert-butyl(2S)-2-[[(2S)-4- (cyclopentylamino)-3-hydroxy-4-oxo-l-[(3S)-2-oxopyrrolidin-3-yl]butan-2- yl]carbamoyl]piperidine-l-carboxylate (160 mg, 47.34% yield) as a white solid. MS Calcd. : 480.61, MS found: 465.86

[0179] Step 7. Experimental procedure for compound 10

[0180] Tert-butyl (2S)-2-(((2S)-4-(cyclopentylamino)-3-hydroxy-4-oxo-l-((S)-2- oxopyrrolidin-3-yl)butan-2-yl)carbamoyl)piperidine-l-carboxylate (260.0 mg, 0.541 mmol, 1.00 eq.) was dissolved in DCM (4.00 mL), TFA (370.1 mg, 3.246 mmol, 6.00 eq.) was added and stirred at room temperature for lh. The reaction was concentrated under reduced pressure to give 4-l(2S)-N-[(2S)-4-(cyclopentylamino)-3-hydroxy-4- oxo-l-[(3S)-2-oxopyrrolidin-3-yl]butan-2-yl]piperidine-2-carboxamide TFA salt (268 mg, 100% yield) as yellowish oil. MS Calcd.: 380.49, MS found: 381.69 [M + H]+.

[0181] Step 8. Experimental procedure for compound 12

[0182] (2S)-N-((2S)-4-(cyclopentylamino)-3-hyd roxy-4-oxo-l-((S)-2-oxopyrrolidin-3- yl)butan-2-yl)piperidine-2-carboxamide TFA salt (260.0 mg, 0.526 mmol, 1.00 eq.) and (5-methylisoxazole-3-carbonyl)-L-valine TFA salt (179.0 mg, 0.526 mmol, 1.00 eq.) were dissolved in DCM (5 mL) at 0 °C, DIPEA(DIEA, Hunig's base) (271.9 mg, 2.104 mmol, 4.00 eq.) was then added and the solution was allowed to stir at 0 °C for 5 min. HATU (300.0 mg, 0.789 mmol, 1.50 eq.) was added and the resultant solution was stirred at 0 °C for 2h. The reaction solution was dissolved in ethyl acetate, and then washed with water (20 mL) and brine (20 ml_) . The organic layer was collected and subsequently dried with anhydrous Na2SC>4 and filtered. This filtrate was collected and concentrated. This crude oil was then purified by chromatography on Silica gel (1%-10%CH30H in CH2CI2) to afford 4-lN-[(2S)-l-[(2S)-2-[[(2S)-4-(cyclopentylamino)-3-hydroxy-4- oxo- l-[(3S)-2-oxopyrrolidin-3-yl]butan-2-yl]carbamoyl]piperid in-1 -yl]-3-methyl-l- oxobutan-2-yl]-5-methyl-l,2-oxazole-3-carboxamide (210 mg, crude). MS Calcd. : 588.71, MS found: 589.80 [M + H]+.

[0183] Step 5 Experimental procedure for Example C8

[0184] 4-lN-[(2S)-l-[(2S)-2-[[(2S)-4-(cyclopentylamino)-3-hydroxy-4-oxo-l-[(3S)-2- oxopyrrolidin-3-yl]butan-2-yl]carbamoyl]piperidin-l-yl]-3-methyl-l-oxobutan-2-yl]-5- methyl-l,2-oxazole-3-carboxamide (200.0 mg, 0.340 mmol, 1.00 eq., crude) was dissolved in ACN (6.00 mL) at room temperature, IBX (190 mg, 0.68 mmol, 2.00 eq.) was added and stirred at 80 °C under nitrogen for lh. The reaction mixture was cooled to room temperature and filtered, the organic layer was concentrated under reduced pressure. The crude was purified by prep-HPLC (30ML30%-43%-17MIN-A2-B2- NH3H2O, twice) to give Example C8 (2.00 mg, 1.01% yield) as a white solid.

[0185] Biochemical assays (HRV-14, EV-D68, EV-A71 and CV-B3 3Cpro) and respective activity summary

[0186] Legends:

[0187] IC50 > 100 μM

[0188] + : IC50 20 - 100 μM

[0189] + + : IC50 1 - 20 μM

[0190] + + + : IC50 100 nM - 1 μM

[0191] + + + + : IC50 < 100 nM

[0192] Biochemical assay (SARS-CoV-2 3CLPro) and respective activity summary Legends:

[0193] IC50 > 10 μM

[0194] Recombinant protein expression and purification

[0195] The 3C protease domain from Enterovirus-D68 (Accession No. EF107098.1) was cloned into pET29a (+) with a non-cleavable C terminus His tag by Genscript (Piscataway, NJ, USA). The codon optimized plasmid for E. coli expression was transformed into competent Rosetta (DE3) cells. A single colony was picked to inoculate 10 mL of Terrific Broth (TB) supplemented with 50 pg / ml Kanamycin and 30 pg / ml Chloramphenicol and grown at 37 °C with shaking at 230 rpm. The 10-mL inoculum was added to 1 L of TB and induced with 0.5 mM IPTG for 3hrs at 37°C. The cell pellet was resuspended in lysis buffer (100 mM HEPES pH 7.5, 500 mM NaCI, 10 mM Imidazole, 5% glycerol, 0.5 mM DTT, and 10 pg / mL DNase I), and lysed by sonication (30% amplitude, 2 seconds on / 2 seconds off). Cell debris were removed by centrifugation at 20,000 rpm for 30 mins at 4°C. The supernatant was loaded onto equilibrated HisTrap HP column (Cytiva). The column was washed with lysis buffer containing 10 mM imidazole, followed by another wash with 25 mM imidazole. Protein was eluted using buffer with 500mM imidazole and further purified by gel filtration chromatography on HiLoad 16 / 600 Superdex 200 prep grade column (Cytiva) with 20 mM HEPES pH 7.5, 300 mM NaCI, 5% glycerol, 0.5 mM DTT. Fractions from resulted peak were pooled and concentrated using centrifugal filter unit of 10,000-molecular-weight-cutoff. The purity and molecular weight of the protein was confirmed with SDS-PAGE and Mass Spectrometry (MS). A predominant peak at 21376 Da was observed by MS which matched with the calculated molecular weight of EV-D68 3Cpro.

[0196] A similar construct design was followed for SARS-CoV-2 3CLpro strain BetaCoV / Wuhan / WIV04 / 2019 (Accession NC_045512). The codon optimized plasmid for E. coli expression was transformed into competent BL21(DE3) cells and similar expression and purification method was followed except that all buffers contained 20mM Tris, pH 7.5, lOOmM NaCI, 2mM DTT and protein was eluted using 300mM imidazole.

[0197] The purity and molecular weight of the protein was confirmed with SDS-PAGE MS. A predominant peak at 34863 Da was observed by MS which matched with the calculated molecular weight of SARS-CoV-2 C-His-3CLpro without the N-terminal Methionine residue.

[0198] A similar construct design was followed for EV-A71 3Cpro strain Anhuil-09-China (Accession GQ994988) and coxsackievirus B3 strain Beijing0811 (Accession GQ141875.1) by cloning into pET29a with C-terminal 6X His tag. The codon optimized plasmid for E. coli expression was transformed into Rosetta (DE3) and BL21(DE3), respectively. The expression conditions for both were similar to EV-D68 3Cpro except that EV-A71 3Cpro was cultured in Modified Terrific Broth (TB) instead of LB media. The protein was purified using HisTrap HP column and gel filtration chromatography using HiLoad 16 / 600 Superdex 200 prep grade column. The recombinant proteins were eluted using 20 mM HEPES pH7.5, 500 mM NaCI, 500 mM Imidazole, 5% Glycerol and 0.5 mM DTT. The purity and molecular weight of the protein was confirmed with SDS-PAGE MS. A predominant peak at 21358 Da and 21427 Da was observed by MS for EV-A71 and CV-B3 3Cpro, respectively. The recombinant EV-D68 3Cpro and SARS-CoV-2 3CLpro protein were stored in 20 mM HEPES pH 7.5, 300 mM NaCI, 5% glycerol, l.OmM DTT and 20mM Tris, pH 7.5, 100 mM NaCI, 2.0 mM DTT, respectively.

[0199] Human rhinovirus-14 (HRV-14 3Cpro) with a N-terminus His tag was purchased from Sigma-Aldrich (Cat no: SAE0045). The protein was supplied in 50 mM Tris HCI (pH 7.5), 150 mM NaCI, 1 mM TCEP and 50% (V / V) glycerol.

[0200] The recombinant EV-A71 and CV-B3 3Cpro proteins were stored in 20 mM HEPES pH 7.5, 300 mM NaCI, 5% glycerol, 1.0mM DTT.

[0201] EV-D68 3Cpro protein sequence (SEO ID 1)

[0202] MGPGFDFAQAIMKKNTVVARTEKGEFTMLGVHDRVAVIPTHASVGETIYINDVETKVLDACALRD LTDTNLEITIVKLDRNQKFRDIRHFLPRYEDDYNDAVLSVHTSKFPNMYIPVGQVTNYGFLNLGGT PTHRILMYNFPTRAGQCGGVVTTTGKVIGIHVGGNGAQGFAAMLLHSYFTDTQLEHHHHHH

[0203] SARS CoV-2 3CL pro protein sequence (SEO ID 2)

[0204] MSGFRKMAFPSGKVEGCMVQVTCGTTTLNGLWLDDVVYCPRHVICTSEDMLNPNYEDLLIRKSN HNFLVQAGNVQLRVIGHSMQNCVLKLKVDTANPKTPKYKFVRIQPGQTFSVLACYNGSPSGVYQ CAMRPNFTIKGSFLNGSCGSVGFNIDYDCVSFCYMHHMELPTGVHAGTDLEGNFYGPFVDRQTA

[0205] QAAGTDTTITVNVLAWLYAAVINGDRWFLNRFTTTLNDFNLVAMKYNYEPLTQDHVDILGPLSAQ TGIAVLDMCASLKELLQNGMNGRTILGSALLEDEFTPFDVVRQCSGVTFQLEHHHHHH

[0206] EV-A71 3Coro protein sequence (SEO ID 31

[0207] MGPSLDFALSLLRRNIRQVQTDQGHFTMLGVRDRLAVLPRHSQPGKTIWIEHKLVNVLDAVELVD EQGVNLELTLITLDTNEKFRDITKFIPENISTASDATLVINTEHMPSMFVPVGDVVQYGFLNLSGKP THRTMMYNFPTKAGQCGGVVTSVGKVIGIHIGGNGRQGFCAGLKRSYFASEQLEHHHHHH

[0208] CV-B3 3Cpro protein sequence (SEO ID 4)

[0209] MGPAFEFAVAMMKRNSSTVKTEYGEFTMLGIYDRWAVLPRHAKPGPTILMNDQEVGVLDAKELV DKDGTNLELTLLKLNRNEKFRDIRGFLAKEEVEVSEAVLAINTSKFPNMYIPVGQVTDYGFLNLGG TPTKRMLMYNFPTRAGQCGGVLMSTGKVLGIHVGGNGHQGFSAALLKHYFNDEQLEHHHHHH

[0210] Biochemical assay method for EV-D68 3Cpro, HRV-14 3Coro. SARS-CoV-2 3CLpro, EV-A71 3Coro and CV-B3 3Coro

[0211] A highly sensitive FRET based protease assay was developed to identify inhibitors of 3C proteases. The test compounds were 3-fold serially diluted in 100% DMSO to 15 concentrations, starting at 3.33 mM. 1.5 pl of the serially diluted compounds were transferred to a black 384 well assay plate (Cat. 781900, Greiner). 23.5 pl of 2.13X concentration of SARS-CoV-2 Chis-3CLpro, EV-D68 Chis-3Cpro or HRV-14C prepared in assay buffer was added to the compounds and incubated for 30 mins at 25°C followed by addition of 25 pl of 2X concentration of substrate.

[0212] The final assay contained 12.5 nM of SARS-CoV-2 Chis-3CLpro with 6 μM peptide 1 substrate in assay buffer containing 50 mM HEPES at pH 7.5, 100 mM NaCI, = 0.01% Triton X-100 and ImM DTT and plates were incubated at 37°C for 1.5hrs. 100 nM of EV-D68 or HRV-14C 3Cpro was tested with 2.0 μM peptide 13 spbstrate in assay bpffer containing 50 mM HEPES (pH 7.5), 1 mM DTT, 0.01% Triton-X and 15% glycerol and incubated for 1 hr at 37°C and 25°C, respectively. The final concentration of DMSO in the assay was 3%. Similarly, assays with EV-A71 3Cpro at 500 nM or CV-B3 3Cpro at 250 nM included 2.0 μM of peptide 13 or peptide 15 substrate in a buffer of 50 mM HEPES (pH 7.5), 1 mM DTT, 0.01% Triton-X, and 15% glycerol, and were incubated for 2 hours at 25°C.The FRET signal was measured using an excitation wavelength of 340 nm (UV(TRF) 340 / 60 nm, Barcode 101), emission wavelength of 490 nm (DSPPsion 486 / 10 filter, Barcode 220) and Lance / DELFIA D400 single mirror (Barcode 412) on Envision plate reader (2104 Envision Multilabel Plate Readers, Perkin Elmer). The dose- dependent inhibition curves were fitted with a variable slope using GraphPad Prism software (GraphPad, USA) to determine a compound's IC50. The substrates, Peptide 1 (Dabcyl)KTSAVLQSGFRKM(Glu)(EDANS), Peptide 13 EDANS-LEVLFQ / GP-DABCYL and Peptide 15 (EDANS-IEALFQ / GP-DABCYL) were synthesized by Genscript.

[0213] Virus assays (HRV-14, EV-D68, EV-A71 and CV-B3) and respective activity summary Legends:

[0214] + : EC50 >20 μM

[0215] + + : EC50 1 - 20 μM

[0216] + + + : EC50 100 nM - 1 μM

[0217] + + + + : EC50 < 100 nM

[0218] "Tested in the presence of 2 μM CP-100356 monohydrochloride

[0219] "Tested in the presence of 2 μM CP-100356 monohydrochloride

[0220] ‘Tested in the absence of 2 μM CP-100356 monohydrochloride

[0221] Compounds were tested for in vitro antiviral activity against enterovirus-68 (EV-68, US / KY / 14-18953; M01 = 0.004) and human rhinovirus-14 (HRV-14, 1059; M01=0.007). EV-68 was tested in RD cells and HRV-14 in HeLa Ohio cells, and test media was MEM supplemented with 5% FBS, 25 mM MgCI2, and 50 pg / mL gentamicin. Cell plates were prepared the day before treatment and infection, seeding cells at 3e4 per well in 96- well plates. Compounds were solubilized in DMSO to prepare 10 mM stock solutions and were then serially diluted using eight half-log dilutions in test media containing efflux inhibitor (final 2 μM on plate) so that the starting (high) test concentration was 50 μM (final DMSO concentration was ≤SO.5%). The final concentration was used to test efflux inhibitor alone at 2 μM. Each dilution was added to 5 wells of a 96-well plate containing cells (0.1 mL per well). Three wells of each dilution were infected with virus (0.1 mL per well), and two wells remained uninfected as toxicity controls. Six wells were infected and untreated as virus controls, and six wells were uninfected and untreated as cell controls. Virus was prepared to achieve a MOI < 0.05. A positive control compound was tested in parallel for each virus. Plates were incubated at 33±2°C, 5% CO2. On day 3 post-infection, once untreated virus control wells reached maximum CPE, plates were stained with neutral red dye for approximately 2 hours (±15 minutes). Supernatant dye was removed, and wells rinsed with PBS, and the incorporated dye was extracted in 50:50 Sorensen citrate buffer / ethanol for >30 minutes and the optical density was read on a spectrophotometer at 540 nm. Optical densities were converted to percent of cell controls and normalized to the virus control, then the concentration of test compound required to inhibit CPE by 50% (EC50) was calculated by regression analysis.

[0222] Alternative protocol:

[0223] Compounds were tested for in vitro antiviral activity against Enterovirus A71 (EV-A71, Tainan / 4643 / 98), Coxsackievirus B3 (CV-B3, HA 201933), Enterovirus D68 (EV-D68, US / KY / 14-18953), and human rhinovirus 14 (HRV-14, 1059). EV-A71 and CV-B3 were tested in Vero 76 cells, EV-D68 in Rhabdomyosarcoma (RD) cells, and HRV-14 in HeLa Ohio cells. Confluent or near-confluent cell culture monolayers were prepared in 96-well plates one day prior to testing. Cells were maintained in MEM supplemented with 5% FBS. For antiviral assays, the same medium was used but with FBS reduced to 2% and supplemented with 50 pg / ml gentamicin.

[0224] Compounds were solubilized in DMSO to prepare 10 mM stock solutions and were then serially diluted using eight half-log dilutions in test media containing CP-100356 monohydrochloride (PZ0171, Sigma-Aldrich), a P-glycoprotein (P-gp) inhibitor (final concentration 2 μM on the plate), so that the starting (high) test concentration was 10 μM (final DMSO concentration was <0.5%). Each dilution was added to 5 wells of a 96- well plate containing cells. Three wells of each dilution were infected with virus, and two wells remained uninfected as toxicity controls. Six wells were infected and untreated as virus controls, and six wells were uninfected and untreated as cell controls. A positive control compound was tested in parallel for each virus.

[0225] On the testing day, the growth media are removed from the cells, and the test compound is applied in a 0.1 ml volume to wells at 2X concentration. Virus, normally at a titer that will cause >80% CPE (usually an MOI <0.003), in a 0.1 ml volume is added to the wells designated for virus infection. Medium devoid of virus is placed in toxicity control wells and cell control wells. Plates are incubated at 37°C with 5% CO2 until marked CPE (>80% CPE for most virus strains) is observed in virus control wells. The plates are then stained with 0.011% neutral red for approximately two hours at 37°C in a 5% CO2 incubator. Supernatant dye is removed, and the wells are rinsed with phosphate-buffered solution (PBS). The incorporated dye is then extracted in a 50: 50 Sorensen citrate buffer / ethanol mixture for >30 minutes, and the optical density is read on a spectrophotometer at 540 nm. Optical densities were converted to a percentage of dye present in untreated control wells and normalized to the virus control. Then, the concentration of the test compound required to inhibit CPE by 50% (EC50) was calculated by regression analysis.

[0226] Selective compounds were tested for in vitro antiviral activity against mouse-adapted Enterovirus A71 (EV-A71, Tainan / 4643 / 98, MP10 Plaque 6) and Enterovirus D68 (EV- D68, US / MO / 14-18949, MP30). The same protocol as above was used, except without CP-100356 monohydrochloride.

[0227] It will be appreciated that many further modifications and permutations of various aspects of the described embodiments are possible. Accordingly, the described aspects are intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

[0228] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0229] Throughout this specification and the claims which follow, unless the context requires otherwise, the phrase "consisting essentially of", and variations such as "consists essentially of" will be understood to indicate that the recited element(s) is / are essential i.e. necessary elements of the invention. The phrase allows for the presence of other non-recited elements which do not materially affect the characteristics of the invention but excludes additional unspecified elements which would affect the basic and novel characteristics of the method defined.

[0230] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

Claims1. A compound of Formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof:wherein R1is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted heteroaryl; R2is selected from optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;R3is selected from H, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted heteroaryl; R4is selected from optionally substituted alkyl or optionally substituted cycloalkyl; R5, R6, R7and R8are independently selected from H or optionally substituted alkyl; or R4and Rs are linked to form an optionally substituted heterocyclyl; n is an integer from 1 to 4; and m is an integer from 1 to 3.

2. The compound according to claim 1, wherein R1is selected from optionally substituted C2-C6 alkyl, optionally substituted spiro or fused cycloalkyl, or optionally substituted heteroaryl.

3. The compound according to claim 1 or 2, wherein R1is selected from4. The compound according to any one of claims 1 to 3, wherein R2is selected from optionally substituted C2-C6alkyl, optionally substituted C4-C8cycloalkyl, optionally substituted C4-C8aryl, optionally substituted C4-C8heteroaryl, optionally substituted (C4-C8)aryl(C1-C4)alkyl, or optionally substituted ( C4-C8)heteroaryl(C1-C4)alkyl.

5. The compound according to any one of claims 1 to 4, wherein R2is selected from6. The compound according to any one of claims 1 to 5, wherein R3 is at a beta position relative to N.

7. The compound according to any one of claims 1 to 6, wherein R3is selected from H, optionally substituted C1-C6alkyl, optionally substituted C3-C10 cycloalkyl, optionally substituted C4-C8aryl or optionally substituted C4-C8heteroaryl.

8. The compound according to any one of claims 1 to 7, wherein R3is selected from H,9. The compound according to any one of claims 1 to 8, wherein R4is selected from optionally substituted C1-C6alkyl or optionally substituted C3-C6cycloalkyl.

10. The compound according to any one of claims 1 to 9, wherein R4is selected from methyl, ethyl, propyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, or phenylmethyl.

11. The compound according to any one of claims 1 to 10, wherein R5, R6, R7and R8are independently selected from H or C1-C6alkyl.

12. The compound according to any one of claims 1 to 11, wherein n is an integer from 1 to 3.

13. The compound according to any one of claims 1 to 12, wherein n is 2.

14. The compound according to any one of claims 1 to 13, wherein m is 1 or 2.

15. The compound according to any one of claims 1 to 14, wherein the compound is represented by Formula16. The compound according to any one of claims 1 to 15, wherein the compound is represented by Formula17. The compound according to any one of claims 1 to 16, wherein the compound is selected from:

18. The compound according to any one of claims 1 to 17, wherein the compound is characterised by IC50 against Enterovirus of less than about 20 μM.

19. The compound according to any one of claims 1 to 18, wherein the compound is characterised by IC50 against human Rhinovirus of less than about 20 μM.

20. The compound according to any one of claims 1 to 19, wherein the compound is characterised by EC50 against Enterovirus of less than about 20 μM.

21. The compound according to any one of claims 1 to 20, wherein the compound is characterised by EC50 against human Rhinovirus of less than about 20 μM.

22. A method of treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV) in a subject in need thereof, comprising administering a therapeutically effective amount of a compound of Formula (I) according to any one of claims 1 to 21 or a pharmaceutically acceptable salt, solvate or prodrug thereof to the subject.

23. A compound of Formula (I) according to any one of claims 1 to 21 or a pharmaceutically acceptable salt, solvate or prodrug thereof for use in treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV).

24. Use of a compound of Formula (I) according to any one of claims 1 to 21 or a pharmaceutically acceptable salt, solvate or prodrug thereof in the manufacture of a medicament for treating a disease or condition caused by Enterovirus (EV) and / or human Rhinovirus (HRV).

25. The method, compound for use or use according to any one of claims 22 to 24, wherein the disease or condition caused by EV and HRV is selected from poliomyelitis,nonspecific febrile, Bornholm disease, sepsis, aseptic meningitis, pericarditis, myocarditis, arrhythmias, heart failure, myocardial infarction, acute hemorrhagic conjunctivitis, herpangina, hand foot mouth disease, encephalitis, fever, muscle pain, sore throat, gastrointestinal distress / abdominal discomfort, headache, nausea, emesis, common cold, acute respiratory distress syndrome (ARDS), acute flaccid myelitis, viral- induced trigger and exacerbation of COPD and asthma, or hand foot mouth disease as well as its respective neurological and cardiac complications.

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