WO2023161427A1 - Viral combination therapy - Google Patents

Abstract

This application describes the medical use of a combination treatment for infections through the inhibition of helicases, especially viral helicases, in combination with the inhibition of viral nucleic acid polymerases. In particular, the inhibition of the coronavirus helicase Nsp13 in combination with an inhibitor of a viral polymerase in the prophylaxis or therapy of a viral infection.

Description

VIRAL COMBINATION THERAPY

This application describes the medical use of a combination treatment for infections through the inhibition of helicases, especially viral helicases, in combination with the inhibition of viral nucleic acid polymerases. In particular, the inhibition of the coronavirus helicase Nspl3 in combination with an inhibitor of a viral polymerase in the prophylaxis or therapy of a viral infection.

Background of the Invention

The viral pandemic caused by the severe respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the worst outbreaks of respiratory diseases in the last century, resulting in more than 4.500.000 deaths since the first appearance of the viral infection in the Chinese province of Wuhan in December 2019. The pandemic has had global socio-economic ramifications, affecting the lives of billions of people everywhere. Yet, to date there is no approved efficacious therapy for the treatment of the disease caused by SARS-CoV- 2 infections, COVID-19. The most promising therapeutic opportunities thus far are repurposing approaches of known antiviral drugs targeting proteases and polymerases that are essential for the replication of viruses, such as remdesivir (HIV), indinavir (HIV), saquinavir (HIV) and lopinavir/ritonavir (HIV, hepatitis C). However, to date there is no targeted approved treatment for COVID-19, and current therapies are focused only on the alleviation of symptoms which may include fever, dry⁷ cough, and pneumonia. Effective singleagent therapies to control viral infections are rare most therapeutically relevant remedies make use of combinations of drugs that target different classes of viral enzymes. This is exemplified in the currently used therapeutic regimen for human immunodeficiency- virus, which combines the use of nucleoside analogue reverse transcriptase inhibitors with integrase inhibitors or non-nucleoside inhibitors, effectively controlling viral loads in infected individuals (Phanuphak & Gulick, 2020). For coronaviruses, the area of combination therapies is largely unexplored and current clinical trials focus on single-agent therapies. Thus, there is a great medical need for targeted combination treatments of human coronavirus infections, especially in the light of current reports shoyving declining antibody titers in patients post COVID- 19 infections, questioning the efficacy of vaccines (Long, Q, et al. (2020) Nat. Med., https://doi.org/10.1038/s41591-020-0965-6).

Coronaviruses are single-stranded, positive-strand RNA viruses, of which seven types have been shown to infect humans: 229E, NL63, OC43, HKU1, MERS-CoV, SARS-CoV and SARS-CoV-2. The symptoms of infections range from mild respiratory⁷ distress to more severe illnesses that can be lethal. The 29.9 kb SARS-CoV-2 genome contains at least six open reading frames (ORFs), of which the first ORF (ORFla/b) constitutes >70% of the genome. It encodes for 16 non-structural proteins (nspl-16) which have been shown to play a major role in viral replication. The four main structural proteins including spike, envelope, membrane and nucleocapsid are encoded by ORFs near the 3 '-end of the genome. These proteins are important for virion assembly and cell entry, ultimately causing cellular coronavirus infection. Additionally, specific structural and accessory⁷ proteins such as HE protein are also encoded by the coronavirus genome (Chen, Y. etal. (2020) J. Med. Virol., 92:418-423). Interestingly, SARS-CoV-2 shares more than ~80% identity on the nucleotide level to the first identified less infectious but more lethal SARS epidemic virus (L.E. Gralinski, V.D Menachery (2020) Viruses, 12: 135).

Surprisingly, the structural proteins of coronaviruses show great variability among the different coronavirus species while the key non-structural proteins (NSPs), and particularly the helicase Nspl3, have been shown to be much more conserved. In particular, the viral helicases of the SARS-CoV and SARS- CoV-2 Coronaviridae show more than 99% sequence identity (see Fig. 1). Quite strikingly there is a close evolutionary' relationship among viral helicases and in particular the viral helicases of the Coronaviridae (see Fig. 2). The amino acid sequence comprising the allosteric pocket is also highly conserved among the class of Pisoniviricetes, in particular the order Nidovirales, more particularly the suborder of Comidovirineae and most particularly the family of Coronaviridae and shows at least 57% sequence identity and more than 28% similarity among Coronaviridae (see Fig. 3). The structure of the MERS-CoV and the SARS-CoV and SARS-CoV2 Nspl3 helicases have been solved by X-ray crystallography (see Hao, W. et l. (2017) PLos Pathog, 13: el006474-e 1006474 and Jia, Z. et al. (2019) Nucleic Acids Res 47: 6538- 6550) Fig. 4), showing a high degree in structural similarity with overall RMSD values in the range of 1.15 and 1.6 A². The proteins belong to the SF1 superfamily of helicases and consist of five domains: an N- terminal zinc binding domain (ZBD), a helical stalk domain, the IB domain and the two RecA-like domains 1A and 2 A, which contain the six conserved active site motifs. Thus, it is particularly preferred that infection with viruses comprising helicases belonging to the SF1 superfamily are treated with the compounds of the present invention.

Viral helicases are motor proteins that use energy derived from ATP hydrolysis to catalyze the unwinding of RNA or DNA duplex oligonucleotides into single strands in a 5' to 3' direction. This enzymatic activity is absolutely necessary for viral genome replication and it has been shown to be required in transcription of viral mRNAs, translation, disruption of RNA-protein complexes, and packaging of nucleic acids into virions. Importantly, the validation of helicases as antiviral drug targets to reduce the viral replication has been demonstrated in animal models for the herpes simplex helicase (Crute, J. J., et al. (2002) Nat Med., 8:386-391 and Kleymann G, et al. (2002) Nat Med. 2002;8:392-398).

However, the development of non-toxic helicase inhibitors has historically been considered much more challenging than developing drugs targeting other viral enzymes, as the helicase ATP -binding site is conserved not only in the different classes of nucleic-acid regulated helicases, but also in in motor proteins, small GTPases, kinases, the AAA⁺ family of ATPases, etc. (see Fig 1A from D. N. Frick and A. M. I. Lam (2006) Curr. Pharm. Des., 12(11): 1315-1338). Thus, compounds that inhibit helicases via an ATP competitive mechanism have generally been regarded as potentially toxic due to off-target effects.

The present invention is based on the observation of the present inventors that inhibitors of helicases, in particular viral helicases, and inhibitors of viral polymerases, in particular RNA-directed RNA polymerases (RdRp), inhibit the replication of viruses, in particular single-stranded positive-sense RNA viruses, most of which utilize viral helicases for their replication cycle in at least an additive preferably synergistic way. Amongst the pathogenic RNA viruses, the present invention will be most suitable for viruses including those from severe acute respiratory' syndrome (SARS), middle-east respiratory' syndrome (MERS), Dengue fever virus (DFV), Japanese encephalitis virus (JEV), Tick-bome encephalitis virus (TBE) and West Nile virus (WNV). Other examples of suitable viral targets include the NS3 helicase and NS5B polymerase of hepatitis C virus (HCV), Zika virus, and yellow fever virus; the UL5:UL52:UL8 helicase/primase complex and UL30 polymerase of herpes simplex virus; the large T antigen helicase from human polyomavirus 2; and El helicase of human papillomaviruses (for a review see: Frick DN et al. (2006) Curr. Pharm. Des. 12(11): 1315-1338). Neither retroviruses nor negative-strand viruses encode their own helicases, however the present invention is also applicable to these taxonomies, as they utilize well- described host-cell helicases, which can serve as drug targets for these infections. As an example, HIV replication has been shown to depend on the human host cell DDX3 RNA helicase (Phanuphak & Gulick, 2020). Thus, an inhibitor of DDX3 RNA helicase can be used in a combination therapy with one of the many known inhibitors of HIV RNA polymerase. The same logic applies to those viruses which do not encode their own polymerase, such as those in the family Polyomaviridae or human papillomaviruses (Bhattachagee S. et al. (2017) Can. J. Microbiol. 63(3): 193-211). Additionally, since all polymerase enzymes require single stranded substrates which are produced by helicases, the present invention applies to all polymerase classes, not only the RdRp class but also to DNA dependent RNA polymerase (DdRp). Indeed, even viruses containing single-stranded genetic material require helicases to separate the doublestranded genetic material after the first round of replication by the polymerase. Accordingly, the present inventors have identified novel combination targets and therapeutic strategies for prevention and therapy of viral infection.

Summary of the Invention

In one aspect, the present invention is directed to an inhibitor of a helicase for use in combination with an inhibitor targeting viral replication and/or infection, in particular targeting SARS/CoV replication and/or infection in the prophylaxis or therapy of a viral infection, in particular of SARS/CoV.

In another aspect, the present invention is directed to an inhibitor targeting viral replication and/or infection, in particular targeting SARS/CoV replication and/or infection for use in combination with an inhibitor of a helicase in the prophylaxis or therapy of a viral infection, in particular of SARS/CoV.

In a first aspect, the present invention is directed to an inhibitor of a helicase for use in combination with an inhibitor of a viral polymerase in the prophylaxis or therapy of a viral infection.

In a second aspect, the present invention is directed to an inhibitor of a viral polymerase for use in combination with an inhibitor of a helicase in the prophylaxis or therapy of a viral infection.

In a third aspect, the present invention is directed to a pharmaceutical composition comprising the inhibitor of a helicase as defined in the first aspect and the inhibitor of a viral polymerase as defined in the second aspect either separately or in admixture and at at least one pharmaceutically acceptable excipient.

In a fourth aspect, the present invention is directed to the pharmaceutical composition of the third aspect for use in medicine, preferably for use in the prophylaxis or therapy of an infection with an RNA or DNA virus, preferably a single or double stranded RNA virus, more preferably a single stranded RNA virus. Description of the Figures

Fig. 1 Shows the sequence divergence between non-structural proteins of SARS-CoV and SARS-CoV-2 (Fig. 1 of Frick, D.N. et al (2020) Biochemistry, 59:2608-2615). The viral helicase Nspl3 is the most conserved protein among the NSPs with a sequence identity at the amino acid level of >99%. Fig. 2 Panel (A) shows the evolutionary relationship of viral helicases to other viral and cellular helicases (taken from Frick & Lam (2006) supra). Panel (B) shows the phylogenetic tree of the seven known human Coronavirus (CoV) helicases (B).

Fig- 3 Shows an alignment of the helicase that forms the allosteric binding pocket from the seven Coronaviruses, namely Nspl3 helicase of HCoV-229E (SEQ ID NO: 2) referred to as “229E” in the figure, Nspl3 helicase of HCoV-NL63 (SEQ ID NO: 3) referred to as “NL-63” in the figure, Nspl3 helicase of HCoV OC43 (SEQ ID NO: 4) referred to as “OC43” in the figure, Nspl3 helicase of HCoV HKU1 (SEQ ID NO: 5) referred to as “HKU1” in the figure, Nspl3 helicase of MERS CoV (SEQ ID NO: 6), Nspl3 helicase of SARS CoV (SEQ ID NO: 7) and Nspl3 helicase SARS CoV2 (SEQ ID NO: 1). The allosteric binding pockets of the seven coronavirus helicases are highlighted by a box. In SARS CoV2 the allosteric binding pocket spans S236-T440. Out of those 205 amino acids only 28 form the binding pocket. These amino acids are highlighted by bold print in SARS-CoV2 and also in the six other Coronavirus helicases. Within the 28 amino acids forming the binding pocket 57.1% of the amino acid residues are identical, 17.9% are highly similar, 10.7% similar, and 14.3% are different. Accordingly, within the region relevant for the interaction of the compounds of the present invention the seven coronavirus helicases have a homology of 85.7%. Furthermore, the alignment led to the identification of several conserved motifs with the coronavirus helicases, which are highlighted in all seven amino acid sequences by underline. Furthermore, amino acids highlighted in light grey are absolutely conserved in the active site motifs.

Fig. 4 Panel (A) shows a cartoon representation of the structure of the SARS-CoV2 Nspl3 (taken from PDB 6XEZ, Chen et al., 2020, Cell 182, 1-14). The N-terminal zinc binding domain (ZBD) with three bound zinc ions (dark spheres), the stalk domain, the IB domain and the two RecA-like domains 1A and 2A are labelled accordingly. The nucleotide binding cleft with the bound transition state analog A DP- AR is indicated by an arrow. Panel (B) highlights the RecA lobes 1A and 2A, the conserved residues from the six active site motifs are shown as sticks. The transition state analog ADP-AF₃ (grey) and the co-factor Mg²⁺ (black) are shown as spheres. The location of the newly identified allosteric pocket is indicated by the surface representation and does not overlap with the nucleotide binding site.

Fig. 5 Panel (A) shows the top view of the sliced surface of SARS-CoV2 Helicase domain N-Terminal Lobe S236-T440 (Lobe 1) with its tripartite pocket consisting of entry channel (1), left channel (2), and right channel (3), and active site (4) circled. Panel (B) shows the bottom view of the sliced surface of SARS-CoV2 Helicase domain N-Terminal Lobe S236-T440 (Lobe 1) with its tripartite pocket consisting of entry channel (1), left channel (2), and right channel (3), and active site (4) circled.

Fig. 6 A) Top view of the sliced surface of SARS-CoV-2 helicase domain Lobe 1A with colored by hydrophobicity with hydrophilic regions shown in white and hydrophobic regions shown in black. B) Bottom view of the sliced surface of SARS-CoV-2 helicase domain Lobe 1A colored by hydrophobicity with hydrophilic regions shown in white and hydrophobic regions shown in black. Fig. 7 A) Top view of the sliced surface of SARS-CoV-2 helicase domain Lobe 1A with compound COVI-3 addressing the entry channel and right channel. B) Bottom view of the sliced surface of SARS-CoV-2 helicase domain Lobe 1A with compound COVID Inhibitor (COVI) 3 (COVI-3) addressing the entry channel and right channel. C) Top view of the sliced surface of SARS-CoV2 Helicase domain Lobe 1 with compound COVI- 10 addressing the entry channel, right channel, and left channel. D) Bottom view of the sliced surface of SARS-CoV2 helicase domain Lobe 1 A with compound COVLIO addressing the entry channel, right channel, and left channel. E) Top view of the sliced surface of SARS-CoV2 Helicase domain Lobe 1 with compound COVI-35 addressing the entry channel and right channel. F) Bottom view of the sliced surface of SARS-CoV2 helicase domain Lobe 1A with compound COVI-35 addressing the entry channel and right channel.

Fig- 8 Panel (A) shows the molecular surface of compound COVI- 10 shown from three different angles. Region 1 contains polar substituents while regions 2 and 3 are largely unpolar. Panel (B) The molecular surface of compound COVI-3 shown from three different angles. Region 1 contains polar substituents while regions 2 and 3 are largely unpolar. (C) The molecular surface of compound COVI-35 shown from three different angles. Region 1 contains polar substituents while region 2 is unpolar.

Fig- 9 Panel (A) shows top view of the surface of compound COVI- 10 surrounded by the residues making up the binding pocket of the SARS-CoV2 helicase domain lobe 1 A. Panel (B) Bottom view of the surface of compound COVI- 10 surrounded by the residues making up the binding pocket of the SARS-CoV-2 Helicase domain lobe 1. Panel (C) Top view of the surface of compound COVI-3 surrounded by the residues making up the binding pocket of the SARS-CoV2 Helicase domain lobe 1. Panel (D) Bottom view of the surface of compound COVI-3 surrounded by the residues making up the binding pocket of the SARS-CoV2 Helicase domain lobe 1. Panel (E) Top view of the surface of compound COVI-35 surrounded by the residues making up the binding pocket of the SARS-CoV2 Helicase domain lobe 1. Panel (F) Bottom view of the surface of compound COVI- 35 surrounded by the residues making up the binding pocket of the SARS-CoV2 Helicase domain lobe 1.

Fig. 10 Panel (A) shows the bottom view of compound COVI-IO showing specific interactions with N158, F143, and 1169. B) Bottom view of compound COVI-3 showing specific interations with N158. C) Top view of compound COVI-35 showing specific interations with M429.

Fig. 11 Panel (A) shows a ligplot diagram of compound CO VI-10 in the allosteric binding site of SARS- CoV2 Nspl3 lobe 1. Panel (B) shows a ligplot diagram of compound COVI-3 in the allosteric binding site of SARS-CoV2 Nspl3 lobe 1. Panel (C) shows a ligplot diagram of compound COVI- 35 in the allosteric binding site of SARS-CoV2 Nspl3 lobe 1.

Fig. 12 Shows dose response curves of the active SARS-CoV-2 Nspl3 inhibitors tested in a FRET-based DNA unwinding helicase assay.

Fig. 13 Shows a dose response curves of selected SARS-CoV2 Nspl3 inhibitors tested in a malachite green based ATPase assay.

Fig. 14 Table indicating the structures of the COVI inhibitors and the respective IC50 determined in the DNA unwinding and ATPase assays.

Fig. 15 Shows dose response curves of remdesivir with 25 pM of SARS-CoV2 Nspl3 inhibitors tested in a cytopathic effect (CPE) assay.

Fig. 16 Shows dose response curves of selected Nspl3 inhibitors tested in a cellular infection assay with the 229E coronavirus.

Fig. 17 Shows dose response curves of selected SARS-CoV2 Nspl3 inhibitors tested in SARS-CoV-2 nanoluciferase assay.

Fig. 18 Shows 2D synergy map for COVI-3 or COVI-20 and Remdesivir drug combination on SARS-CoV- 2 infected VeroE6 cells followed by TCID50 determination of infectious viral titers. Generated using SynergyFinder 2.0 (lanevski et al., 2020).

Fig. 19 Shows synergy for COVI-3, COVI-35 and COVI-5 with the orally bioavailable Molnupiravir. Virus release in SARS-CoV-2 infected cell culture supernatant (VeroE6 cells).

Fig. 20 A general synthesis scheme for compounds of formula (I) comprising a pyrazole core structure. The three substituents which are subsequently covalently coupled to the core are shown without substituents but can either comprise such substituents when coupled and/or can comprise protection groups that protect such substituents during the coupling reaction and which are subsequently removed or they can comprise protection groups that can subsequently be cleaved to create new reactive groups to which the desired substituent is ultimately coupled as commonly known in the art.

Fig. 21 A general synthesis scheme for compounds of formula (II) comprising a quinazoline core structure. The two substituents which are subsequently covalently coupled to the core are shown without substituents but can either comprise such substituents when coupled and/or can comprise protection groups that protect such substituents during the coupling reaction and which are subsequently removed or they can comprise protection groups that can subsequently be cleaved to create new reactive groups to which the desired substituent is ultimately coupled as commonly known in the art.

Fig. 22 A general synthesis scheme for compounds of formula (III)

Fig. 23 A list of suppliers from which each compound was obtained under confidentiality obligation.

Fig. 24 Shows in-silico estimated binding affinities of Sars-CoV-2 Nspl3 inhibitors to other viral helicases. Detailed Description of the Invention

Before the present invention is described in detail below, it is to be understood that this invention is not limited to the particular methodology, protocols and reagents described herein as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention, which will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.

Several documents are cited throughout the text of this specification. Each of the documents cited herein (including all patents, patent applications, scientific publications, manufacturer's specifications, instructions, etc.), whether supra or infra, are hereby incorporated by reference in their entirety. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.

To practice the present invention, unless otherwise indicated, conventional methods of chemistry, biochemistry, and recombinant DNA techniques are employed which are explained in the literature in the field (cf., e.g., Molecular Cloning: A Laboratory Manual, 2^nd Edition, J. Sambrook et al. eds., Cold Spring Harbor Laboratory Press, Cold Spring Harbor 1989).

Definitions

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. As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents, unless the content clearly dictates otherwise.

In the following paragraphs, definitions of the terms: alkyl, heteroalkyl, haloalkyl, cycloalkyl, heterocycloalkyl, aryl, aralkyl, heteroaryl, heteroaralkyl, alkenyl, cycloalkenyl, heteroalkenyl, heterocycloalkenyl, and alkynyl are provided. These terms will in each instance of its use in the remainder of the specification have the respectively defined meaning and preferred meanings. Nevertheless, in some instances of their use throughout the specification preferred meanings of these terms are indicated.

The term "alkyl" refers to a saturated straight or branched carbon chain. Preferably, the chain comprises from 1 to 10 carbon atoms, i.e. 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, e g. methyl, ethyl, propyl (n-propyl or iso-propyl), butyl (n-butyl, iso-butyl, sec-butyl, tert-butyl), pentyl, hexyl, heptyl, octyl, nonyl, decyl. Alkyl groups are optionally substituted.

The term "heteroalkyl" refers to a saturated straight or branched carbon chain. Preferably, the chain comprises from 1 to 9 carbon atoms, i.e. 1, 2, 3, 4, 5, 6, 7, 8, or 9, e.g. methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, which is interrupted one or more times, e.g. 1, 2, 3, 4, 5, with the same or different heteroatoms. Preferably, the heteroatoms are selected from 0, S, and N, e.g. -(CH₂)n-X-(CH₂)_mCH₃, with n = 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9, m = 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 and X = S, O or NR¹ with R¹ = H or hydrocarbon (e.g. Ci to Ce alkyl). In particular, "heteroalkyl" refers to -O-CH₃, -OC2H5, -CH2-O-CH3, -CH2-O-C2H5, -CH2-O-C3H7, -CH₂-O-C4H₉, -CH2-O- C5H11, -C2H4-O-CH3, -C2H4-O-C2H5, -C2H4-O-C3H7, -C2H4-O-C4H9 etc. Heteroalkyl groups are optionally substituted.

The term "haloalkyl" refers to a saturated straight or branched carbon chain in which one or more hydrogen atoms are replaced by halogen atoms, e.g. by fluorine, chlorine, bromine or iodine. Preferably, the chain comprises from 1 to 10 carbon atoms, i.e. 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. In particular, "haloalkyl" refers to -CH₂F, -CHF₂, -CF₃, -C2H4F, -C2H3F2, -C2H2F3, -C2HF4, -C2F5, -C₃H₆F, -C3H5F2, -C3H4F3, - C3H3F4, -C3H2F5, -C₃HF₆, -C3F7, -CH2CI, -CHCI2, -CCh, -C2H4CI, -C2H3CI2, -C2H2CI3, -C₂HC1₄, -C2CI5, - CsHeCl, -C3H5CI2, -C3H4CI3, -CsHsCU, -C3H2CI5, -CbHCl,,. and -C3CI7. Haloalkyl groups are optionally substituted.

The terms "cycloalkyl" and "heterocycloalkyl" alone or in combination with other terms, represent, unless otherwise stated, cyclic versions of "alkyl" and "heteroalkyl", respectively, with preferably 3, 4, 5, 6, 7, 8, 9 or 10 atoms forming a ring, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl etc. The terms "cycloalkyl" and "heterocycloalkyl" are also meant to include bicyclic, tricyclic and polycyclic versions thereof. If bicyclic, tricyclic or polycyclic rings are formed, it is preferred that the respective rings are connected to each other at two adjacent carbon atoms, however, alternatively the two rings are connected via the same carbon atom, i.e. they form a spiro ring system or they form "bridged" ring systems, preferably tricycle [3.3.1.1^3,7] decan. The term "heterocycloalkyl" preferably refers to a saturated ring having five members of which at least one member is an N, 0 or S atom and which optionally contains one additional 0 or one additional N; a saturated ring having six members of which at least one member is an N, 0 or S atom and which optionally contains one additional O or one additional N or two additional N atoms; or a saturated bicyclic ring having nine or ten members of which at least one member is an N, O or S atom and which optionally contains one, two or three additional N atoms. "Cycloalkyl" and "heterocycloalkyl" groups are optionally substituted. Additionally, for heterocycloalkyl, a heteroatom can occupy the position at which the heterocycle is attached to the remainder of the molecule. Examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, spiro[3,3]heptyl, spiro[3,4]octyl, spiro[4,3]octyl, spiro[3,5]nonyl, spiro[5,3]nonyl, spiro[3,6]decyl, spiro[6,3]decyl, spiro[4,5]decyl, spiro[5,4]decyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, adamantyl, and the like. Examples of heterocycloalkyl include l-(l,2,5,6-tetrahydropyridyl), 1-piperidinyl, 2-piperidinyl, 3- piperidinyl, 4-morpholinyl, 3-morpholinyl, l,8-diazo-spiro[4,5]decyl, l,7-diazo-spiro[4,5]decyl, 1,6- diazo-spiro[4,5]decyl, 2,8-diazo-spiro[4,5]decyl, 2,7-diazo-spiro[4,5]decyl, 2,6-diazo-spiro[4,5]decyl, 1,8- diazo-spiro[5,4]decyl, 1,7 diazo-spiro[5,4]decyl, 2,8-diazo-spiro[5,4]decyl, 2,7-diazo-spiro[5,4]decyl, 3,8- diazo-spiro[5,4]decyl, 3,7-diazo-spiro[5,4]decyl, l,4-diazabicyclo[2.2.2]oct-2-yl, tetrahydroftiran-2-yl, tetrahydrofuran-3-yl, tetrahydrothien-2-yl, tetrahydrothien-3-yl, 1-piperazinyl, 2-piperazinyl, and the like.

The term "aryl" preferably refers to an aromatic monocyclic ring containing 6 carbon atoms, an aromatic bicyclic ring system containing 10 carbon atoms or an aromatic tricyclic ring system containing 14 carbon atoms. Examples are phenyl, naphthyl or anthracenyl. The aryl group is optionally substituted. The term "aralkyl" refers to an alkyl moiety, which is substituted by aryl, wherein alkyl and aryl have the meaning as outlined above. An example is the benzyl radical. Preferably, in this context the alkyl chain comprises from 1 to 8 carbon atoms, i.e. 1, 2, 3, 4, 5, 6, 7, or 8, e.g. methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl. The aralkyl group is optionally substituted at the alkyl and/or aryl part of the group. Preferably the aryl attached to the alkyl has the meaning phenyl, naphthyl or anthracenyl.

The term "heteroaryl" preferably refers to a five or six-membered aromatic monocyclic ring wherein at least one of the carbon atoms is replaced by 1, 2, 3, or 4 (for the five membered ring) or 1, 2, 3, 4, or 5 (for the six membered ring) of the same or different heteroatoms, preferably selected from 0, N and S; an aromatic bicyclic ring system with 8 to 12 members wherein 1, 2, 3, 4, 5, or 6 carbon atoms of the 8, 9, 10, 11 or 12 carbon atoms have been replaced with the same or different heteroatoms, preferably selected from 0, N and S; or an aromatic tricyclic ring system with 13 to 16 members wherein 1, 2, 3, 4, 5, or 6 carbon atoms of the 13, 14, 15, or 16 carbon atoms have been replaced with the same or different heteroatoms, preferably selected from 0, N and S. Examples are furanyl, thiophenyl, oxazolyl, isoxazolyl, 1,2,4-oxadiazolyl, 1,2,3-oxadiazolyl, pyrrolyl, imidazolyl, pyrazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, thiazolyl, isothiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, pyridinyl, pynmidinyl, pyrazinyl, 1,2,3- triazinyl, 1,2,4-triazinyl, 1,3,5-triazinyl, 1 -benzofuranyl, 2-benzofuranyl, indoyl, isoindoyl, benzothiophenyl, 2-benzothiophenyl, IH-indazolyl, benzimidazolyl, benzoxazolyl, indoxazinyl, 2,1- benzosoxazoyl, benzothiazolyl, 1,2-benzisothiazolyl, 2,1-benzisothiazolyl, benzotriazolyl, quinolinyl, isoquinolinyl, 2,3-benzodiazinyl, quinoxalinyl, quinazolinyl, quinolinyl, 1,2,3-benzotriazinyl, or 1,2,4- benzotriazinyl. The heteroaryl group may be optionally substituted.

The term "heteroaralkyl" refers to an alkyl moiety, which is substituted by heteroaryl, wherein alkyl and heteroaryl have the meaning as outlined above. An example is the 2-alkylpyridinyl, 3-alkylpyridinyl, or 2-methylpyridinyl radical. Preferably, in this context the alkyl chain comprises from 1 to 8 carbon atoms, i.e. 1, 2, 3, 4, 5, 6, 7, or 8, e.g. methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl. The heteroaralkyl group is optionally substituted at the alkyl and/or heteroaryl part of the group. Preferably the heteroaryl attached to the alkyl has the meaning oxazolyl, isoxazolyl, 1,2,5- oxadiazolyl, 1,2,3-oxadiazolyl, pyrrolyl, imidazolyl, pyrazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, thiazolyl, isothiazolyl, 1,2,3-thiadiazolyl, 1,2,5-thiadiazolyl, pyridinyl, pyrimidinyl, pyrazinyl, 1,2,3-triazinyl, 1,2,4- triazinyl, 1,3,5-triazinyl, 1 -benzofuranyl, 2-benzofuranyl, indoyl, isoindoyl, benzothiophenyl, 2- benzothiophenyl, IH-indazolyl, benzimidazolyl, benzoxazolyl, indoxazinyl, 2,1-benzosoxazoyl, benzothiazolyl, 1,2-benzisothiazolyl, 2,1-benzisothiazolyl, benzotriazolyl, 2,3-benzodiazinyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, quinolinyl, 1,2,3-benzotriazinyl, or 1,2,4-benzotriazinyl. The heteroaralkyl group may be optionally substituted at the alkyl and/or heteroaryl part of the group.

The terms "alkenyl" and "cycloalkenyl" refer to olefinic unsaturated carbon atoms containing chains or rings with one or more double bonds. Examples are propenyl and cyclohexenyl. Preferably, the alkenyl chain comprises from 2 to 8 carbon atoms, i.e. 2, 3, 4, 5, 6, 7, or 8, e.g. ethenyl, 1-propenyl, 2- propenyl, iso-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, iso-butenyl, sec-butenyl, 1 -pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, hexenyl, heptenyl, octenyl. Preferably the cycloalkenyl ring comprises from 3 to 8 carbon atoms, i.e. 3, 4, 5, 6, 7, or 8, e.g. 1 -cyclopropenyl, 2-cyclopropenyl, 1-cyclobutenyl, 2-cyclobutenyl, 1 -cyclopentenyl, 2-cyclopentenyl, 3 -cyclopentenyl, 1 -cyclohexenyl, 2-cyclohexenyl, 3 -cyclohexenyl, cycloheptenyl, cyclooctenyl. The "alkenyl" and "cycloalkenyl" groups may be optionally substituted.

The terms “heteroalkenyl” and “heterocycloalkenyl” refer to unsaturated versions of “heteroalkyl” and “heterocycloalkyl”, respectively. Thus, the term “heteroalkenyl” refers to an unsaturated straight or branched carbon chain. Preferably, the chain comprises from 1 to 9 carbon atoms, i.e. 1, 2, 3, 4, 5, 6, 7, 8, 9, which is interrupted one or more times, e g. 1, 2, 3, 4, 5, with the same or different heteroatoms. Preferably, the heteroatoms are selected from 0, S, and N. In case that one or more of the interrupting heteroatoms is N, the N may be present as an -NR'- moiety, wherein R' is hydrogen or hydrocarbon (e.g. Ci to C,. alkyl), or it may be present as an =N- or -N= group, i.e. the nitrogen atom can form a double bond to an adjacent C atom or to an adjacent, further N atom. "Heteroalkenyl" groups are optionally substituted. The term “heterocycloalkenyl” represents a cyclic version of "heteroalkenyl" with preferably 3, 4, 5, 6, 7, 8, 9 or 10 atoms forming a ring. The term "heterocycloalkenyl" is also meant to include bicyclic, tricyclic and polycyclic versions thereof. If bicyclic, tncyclic or polycyclic rings are formed, it is preferred that the respective rings are connected to each other at two adjacent atoms. These two adjacent atoms can both be carbon atoms; or one atom can be a carbon atom and the other one can be a heteroatom; or the two adjacent atoms can both be heteroatoms. However, alternatively the two rings are connected via the same carbon atom, i.e. they form a spiro ring system or they form "bridged" ring systems. The term "heterocycloalkenyl" preferably refers to an unsaturated ring having five members of which at least one member is an N, O or S atom and which optionally contains one additional O or one additional N; an unsaturated ring having six members of which at least one member is an N, O or S atom and which optionally contains one additional 0 or one additional N or two additional N atoms; or an unsaturated bicyclic ring having nine or ten members of which at least one member is an N, 0 or S atom and which optionally contains one, two or three additional N atoms. "Heterocycloalkenyl" groups are optionally substituted. Additionally, for heteroalkenyl and heterocycloalkenyl, a heteroatom can occupy the position at which the heterocycle is attached to the remainder of the molecule.

The term "aralkenyl" refers to an alkenyl moiety, which is substituted by aryl, wherein alkenyl and aryl have the meaning as outlined above.

The term "heteroaralkenyl" refers to an alkenyl moiety, which is substituted by heteroaryl, wherein alkenyl and heteroaryl have the meaning as outlined above.

The term "alkynyl" refers to unsaturated carbon atoms containing chains or rings with one or more triple bonds. Preferably, the alkynyl chain comprises from 2 to 8 carbon atoms, i.e. 2, 3, 4, 5, 6, 7, or 8, e.g. ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4- pentynyl, hexynyl, heptynyl, octynyl. The alkynyl group may be optionally substituted.

The terms "heteroalkynyl", "cycloalkynyl", and "heterocycloalkynyl" refer to moieties that basically correspond to "heteroalkenyl", "cycloalkenyl", and "heterocycloalkenyl", respectively, as defined above but differ from "heteroalkenyl", "cycloalkenyl", and "heterocycloalkenyl" in that at least one double bond is replaced by a triple bond.

As used herein, the term “alicyclic system” includes cycloalkyl, cycloalkenyl, and cycloalkynyl substituents, as defined above.

As used herein, the term "carbocycle" includes monocyclic cycloalkyl, cycloalkenyl, cycloalkynyl and aryl substituents.

As used herein, the term "heterocycle" includes monocyclic heterocycloalkyl, heterocycloalkenyl, heterocycloalkynyl and heteroaryl substituents.

In one embodiment, carbon atoms or hydrogen atoms in alkyl, cycloalkyl, aryl, aralkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl radicals may be substituted independently from each other with one or more elements selected from the group consisting of 0, S, N or with groups containing one or more elements, i.e. 1, 2, 3, 4, 5, 6, or more selected from the group consisting of 0, S, and N.

Embodiments include alkoxy, cycloalkoxy, aryloxy, aralkoxy, alkenyloxy, cycloalkenyloxy, alkynyloxy, alkylthio, cycloalkylthio, arylthio, aralkylthio, alkenylthio, cycloalkenylthio, alkynylthio, alkylamino, cycloalkylamino, arylamino, aralkylamino, alkenylamino, cycloalkenylamino, alkynylamino radicals.

Other embodiments include hydroxyalkyl, hydroxycycloalkyl, hydroxyaryl, hydroxy aralkyl, hydroxyalkenyl, hydroxycycloalkenyl, hydroxy alkynyl, mercaptoalkyl, mercaptocycloalkyl, mercaptoaryl, mercaptoaralkyl, mercaptoalkenyl, mercaptocycloalkenyl, mercaptoalkynyl, aminoalkyl, aminocycloalkyl, aminoaryl, aminoaralkyl, aminoalkenyl, aminocycloalkenyl, aminoalkynyl radicals.

In another embodiment, one or more hydrogen atoms, e.g. 1, 2, 3, 4, 5, 6, 7, or 8 hydrogen atoms in alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, alicyclic system, aryl, aralkyl, heteroaryl, heteroaralkyl, alkenyl, cycloalkenyl, heteroalkenyl, heterocycloalkenyl, alkynyl radicals may be substituted independently from each other with one or more halogen atoms, e g. Cl, F, or Br. One preferred radical is the trifluoromethyl radical.

If two or more radicals can be selected independently from each other, then the term "independently" means that the radicals may be the same or may be different.

The term "optionally substituted" in each instance if not further specified refers to halogen (in particular F, Cl, Br, or I), -N0₂, -CN, -OR"', -NR'R", -C00R'",

CONR'R", -NR'COR", -NR"C0R", -NR'CONRR", -NR'S0₂E, -COR"; -S0₂NR'R", -

OOCR'", -CR"'R""0H, -R"'0H, and -E;

R' and R" is each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, aralkyl, and heteroaryl or together form a heteroaryl, or heterocycloalkyl; R'" and R"" is each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, alkoxy, aryl, aralkyl, heteroaryl, and -NR'R";

E is selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, alkoxyalkyl, heterocycloalkyl, an alicyclic system, aryl and heteroaryl; optionally substituted. As used in the context of the present invention the terms “nucleic acid sequence identity” or “amino acid sequence identity” relate to the percentage of sequence identity. The “nucleic acid sequence identity” or “amino acid sequence identity” is determined by comparing two optimally aligned sequences over a comparison window, wherein the portion of the sequence in the comparison window can comprise additions or deletions (i.e. gaps) as compared to the reference sequence (which does not comprise additions or deletions) for optimal alignment of the two sequences. The percentage is calculated by determining the number of positions at which the identical nucleic acid base or amino acid residue occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison and multiplying the result by 100 to yield the percentage of sequence identity.

As used in this specification the term “identical” in the context of two or more nucleic acids or polypeptide sequences, refers to two or more sequences or subsequences that are the same, i.e. comprise the same sequence of nucleotides or amino acids. Sequences are "substantially identical" to each other if they have a specified percentage of nucleotides or amino acid residues that are the same (e.g., at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity over a specified region), when compared and aligned for maximum correspondence over a comparison window, or designated region as measured using one of the following sequence comparison algorithms or by manual alignment and visual inspection. These definitions also refer to the complement of a test sequence. Accordingly, the term “at least 80% sequence identity” is used throughout the specification with regard to polypeptide and polynucleotide sequence comparisons. This expression preferably refers to a sequence identity of at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% to the respective reference polypeptide or to the respective reference polynucleotide.

As used in this specification the term “sequence comparison” refers to the process wherein one sequence acts as a reference sequence, to which test sequences are compared. When using a sequence comparison algorithm, test and reference sequences are entered into a computer, if necessary subsequence coordinates are designated, and sequence algorithm program parameters are designated. Default program parameters are commonly used, or alternative parameters can be designated. The sequence comparison algorithm then calculates the percent sequence identities or similarities for the test sequences relative to the reference sequence, based on the program parameters. In case where two sequences are compared and the reference sequence is not specified in comparison to which the sequence identity percentage is to be calculated, the sequence identity is to be calculated with reference to the longer of the two sequences to be compared, if not specifically indicated otherwise. If the reference sequence is indicated, the sequence identity is determined on the basis of the full length of the reference sequence indicated by SEQ ID, if not specifically indicated otherwise. In a sequence alignment, the term “comparison window” refers to those stretches of contiguous positions of a sequence which are compared to a reference stretch of contiguous positions of a sequence having the same number of positions. The number of contiguous positions selected may range from 10 to 1000, i.e. may comprise 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 1000 contiguous positions. Typically, the number of contiguous positions ranges from about 20 to 800 contiguous positions, from about 20 to 600 contiguous positions, from about 50 to 400 contiguous positions, from about 50 to about 200 contiguous positions, from about 100 to about 150 contiguous positions.

Methods of alignment of sequences for comparison are well known in the art. Optimal alignment of sequences for comparison can be conducted, for example, by the local homology algorithm of Smith and Waterman (Adv. Appl. Math. 2:482, 1970), by the homology alignment algorithm of Needleman and Wunsch (J. Mol. Biol. 48:443, 1970), by the search for similarity method of Pearson and Lipman (Proc. Natl. Acad. Sci. USA 85:2444, 1988), by computerized implementations of these algorithms (e.g., GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group, 575 Science Dr., Madison, Wis.), or by manual alignment and visual inspection (see, e.g., Ausubel et al., Current Protocols in Molecular Biology (1995 supplement)). Algorithms suitable for determining percent sequence identity and sequence similarity are the BLAST and BLAST 2.0 algorithms, which are described in Altschul et al. (Nuc. Acids Res. 25:3389-402, 1977), and Altschul et al. (J. Mol. Biol. 215:403-10, 1990), respectively. Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/). This algorithm involves first identifying high scoring sequence pairs (HSPs) by identifying short words of length W in the query sequence, which either match or satisfy some positive-valued threshold score T when aligned with a word of the same length in a database sequence. T is referred to as the neighborhood word score threshold (Altschul et al., supra). These initial neighborhood word hits act as seeds for initiating searches to find longer HSPs containing them. The word hits are extended in both directions along each sequence for as far as the cumulative alignment score can be increased. Cumulative scores are calculated using, for nucleotide sequences, the parameters M (reward score for a pair of matching residues; always >0) and N (penalty score for mismatching residues; always <0). For amino acid sequences, a scoring matrix is used to calculate the cumulative score. Extension of the word hits in each direction are halted when: the cumulative alignment score falls off by the quantity X from its maximum achieved value; the cumulative score goes to zero or below, due to the accumulation of one or more negative-scoring residue alignments; or the end of either sequence is reached. The BLAST algorithm parameters W, T, and X determine the sensitivity and speed of the alignment. The BLASTN program (for nucleotide sequences) uses as defaults a wordlength (W) of 11, an expectation (E) or 10, M=5, N=-4 and a comparison of both strands. For amino acid sequences, the BLASTP program uses as defaults a wordlength of 3, and expectation (E) of 10, and the BLOSUM62 scoring matrix (see Henikoff and Henikoff, Proc. Natl. Acad. Sci. USA 89: 10915, 1989) alignments (B) of 50, expectation (E) of 10, M=5, N=-4, and a comparison of both strands. The BLAST algorithm also performs a statistical analysis of the similarity between two sequences (see, e.g., Karlin and Altschul, Proc. Natl. Acad. Sci. USA 90:5873-87, 1993). One measure of similarity provided by the BLAST algorithm is the smallest sum probability (P(N)), which provides an indication of the probability by which a match between two nucleotide or amino acid sequences would occur by chance. For example, a nucleic acid is considered similar to a reference sequence if the smallest sum probability in a comparison of the test nucleic acid to the reference nucleic acid is less than about 0.2, typically less than about 0.01, and more typically less than about 0.001.

Semi-conservative and especially conservative amino acid substitutions, wherein an amino acid is substituted with a chemically related amino acid are preferred. Typical substitutions are among the aliphatic amino acids, among the amino acids having aliphatic hydroxyl side chain, among the amino acids having acidic residues, among the amide derivatives, among the amino acids with basic residues, or the amino acids having aromatic residues. Typical semi-conservative and conservative substitutions are:

Amino acid Conservative substitution Semi-conservative substitution

A G; S; T N; V; C

C A; V; L M; I; F; G

D E; N; Q A; S; T; K; R; H

E D; Q; N A; S; T; K; R; H

F W; Y; L; M; H I; V; A

G A S; N; T; D; E; N; Q

H Y; F; K; R L; M; A

I V; L; M; A F; Y; W; G

K R; H D; E; N; Q; S; T; A

L M; I; V; A F; Y; W; H; C

M L; I; V; A F; Y; W; C;

N Q D; E; S; T; A; G; K; R

P V; I L; A; M; W; Y; S; T; C; F

Q N D; E; A; S; T; L; M; K; R

R K; H N; Q; S; T; D; E; A

S A; T; G; N D; E; R; K

T A; S; G; N; V D; E; R; K; I

V A; L; I M; T; C; N

W F; Y; H L; M; I; V; C

Y F; W; H L; M; I; V; C.

The term “small molecule” as used in the context of the present invention refers to an organic compound with low molecular weight that is capable of modulating biochemical processes in order to diagnose, treat, or prevent diseases. The upper molecular-weight limit for a small molecule is approximately 900 daltons, which allows for the possibility to rapidly diffuse across cell membranes so that it can reach intracellular sites of action. This molecular weight cutoff is also a necessary condition for oral bioavailability as it allows for transcellular transport through intestinal epithelial cells. In addition to intestinal permeability, the molecule must also possess a reasonably rapid rate of dissolution into water and adequate water solubility and moderate to low first pass metabolism. A somewhat lower molecular weight cutoff of 500 daltons is preferred for oral small molecule drugs based on the observation that clinical attrition rates are significantly reduced if the molecular weight is kept below this limit. Accordingly, “low molecular weight” in the context of small molecules means < 900 D, preferably < 700 D and more preferably < 500 D. Larger structures such as nucleic acids and proteins, and many polysaccharides are not small molecules, although their constituent monomers (ribo- or deoxyribonucleotides, amino acids, and monosaccharides, respectively) are often considered small molecules. The term “small molecule inhibitor” as used in the context of the present invention refers to a small molecule that specifically binds to a biological macromolecule, preferably protein and act as an inhibitor of that macromolecule, thereby altering the activity or function of the target macromolecule.

"Pharmaceutically acceptable" means approved by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopeia (United States Pharmacopeia-33/National Formulary-28 Reissue, published by the United States Pharmacopeia Convention, Inc., Rockville Md., publication date: April 2010) or other generally recognized pharmacopeia for use in animals, and more particularly in humans.

The term "pharmaceutically acceptable salt" refers to a salt of a compound of the present invention. Suitable pharmaceutically acceptable salts of the compound of the present invention include acid addition salts which may, for example, be formed by mixing a solution of a compound described herein or a derivative thereof with a solution of a pharmaceutically acceptable acid such as hydrochloric acid, sulfuric acid, fumaric acid, maleic acid, succinic acid, acetic acid, benzoic acid, citric acid, tartaric acid, carbonic acid or phosphoric acid. Furthermore, where the compound of the invention carries an acidic moiety, suitable pharmaceutically acceptable salts thereof may include alkali metal salts (e.g., sodium or potassium salts); alkaline earth metal salts (e.g., calcium or magnesium salts); and salts formed with suitable organic ligands (e.g., ammonium, quaternary ammonium and amine cations formed using counteranions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, alkyl sulfonate and aryl sulfonate). Illustrative examples of pharmaceutically acceptable salts include but are not limited to: acetate, adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate, bromide, butyrate, calcium edetate, camphorate, camphorsulfonate, camsylate, carbonate, chloride, citrate, clavulanate, cyclopentanepropionate, digluconate, dihydrochloride, dodecylsulfate, edetate, edisylate, estolate, esylate, ethanesulfonate, formate, fumarate, gluceptate, glucoheptonate, gluconate, glutamate, glycerophosphate, glycolylarsanilate, hemisulfate, heptanoate, hexanoate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, hydroiodide, 2 -hydroxy ethane sulfonate, hydroxynaphthoate, iodide, isothionate, lactate, lactobionate, laurate, lauryl sulfate, malate, maleate, malonate, mandelate, mesylate, methanesulfonate, methylsulfate, mucate, 2-naphthalenesulfonate, napsylate, nicotinate, nitrate, N- methylglucamine ammonium salt, oleate, oxalate, pamoate (embonate), palmitate, pantothenate, pectinate, persulfate, 3 -phenylpropionate, phosphate/diphosphate, picrate, pivalate, polygalacturonate, propionate, salicylate, stearate, sulfate, subacetate, succinate, tannate, tartrate, teoclate, tosylate, triethiodide, undecanoate, valerate, and the like (see, for example, Berge, S. M., et al, "Pharmaceutical Salts", Journal of Pharmaceutical Science, 1977, 66, 1-19). Certain specific compounds of the present invention contain both basic and acidic functionalities that allow the compounds to be converted into either base or acid addition salts.

The neutral forms of the compounds may be regenerated by contacting the salt with a base or acid and isolating the parent compound in the conventional manner. The parent form of the compound differs from the various salt forms in certain physical properties, such as solubility in polar solvents, but otherwise the salts are equivalent to the parent form of the compound for the purposes of the present invention.

In addition to salt forms, the present invention provides compounds which are in a prodrug form. Prodrugs of the compounds described herein are those compounds that readily undergo chemical changes under physiological conditions to provide a compound of formula (I) to (IV), and especially a compound shown in Fig. 14. A prodrug is an active or inactive compound that is modified chemically through in vivo physiological action, such as hydrolysis, metabolism and the like, into a compound of this invention following administration of the prodrug to a patient. Additionally, prodrugs can be converted to the compounds of the present invention by chemical or biochemical methods in an ex vivo environment. For example, prodrugs can be slowly converted to the compounds of the present invention when placed in a transdermal patch reservoir with a suitable enzyme. The suitability and techniques involved in making and using prodrugs are well known by those skilled in the art. For a general discussion of prodrugs involving esters, see Svensson L.A. and Tunek A. (1988) Drug Metabolism Reviews 19(2): 165-194 and Bundgaard H. “Design of Prodrugs”, Elsevier Science Ltd. (1985). Examples of a masked carboxylate anion include a variety of esters, such as alkyl (for example, methyl, ethyl), cycloalkyl (for example, cyclohexyl), aralkyl (for example, benzyl, p-methoxybenzyl), and alkylcarbonyloxyalkyl (for example, pivaloyloxymethyl). Amines have been masked as arylcarbonyloxymethyl substituted derivatives which are cleaved by esterases in vivo releasing the free drug and formaldehyde (Bundgaard H. et al. (1989) J. Med. Chem. 32(12): 2503- 2507). Also, drugs containing an acidic NH group, such as imidazole, imide, indole and the like, have been masked with N-acyloxymethyl groups (Bundgaard H. “Design of Prodrugs”, Elsevier Science Ltd. (1985)). Hydroxy groups have been masked as esters and ethers. EP 0 039 051 A2 discloses Mannich-base hydroxamic acid prodrugs, their preparation and use.

The compounds of the present invention may also contain unnatural proportions of atomic isotopes at one or more of the atoms that constitute such compounds. For example, the compounds may be radiolabeled with radioactive isotopes, such as for example tritium (³H), iodine-125 (¹²⁵I) or carbon-14 (¹⁴C). All isotopic variations of the compounds of the present invention, whether radioactive or not, are intended to be encompassed within the scope of the present invention.

As used herein, “para position” when referring to the substituent of an aryl means that the substituent occupies the position opposite to the position at which the aryl is linked to the backbone of the compound.

As used herein, a “patient” means any mammal or bird that may benefit from a treatment with the compounds described herein. Preferably, a “patient” is selected from the group consisting of laboratory animals, domestic animals, or primates including chimpanzees and human beings. It is particularly preferred that the “patient” is a human being.

As used herein, "treat", "treating" or “treatment” of a disease or disorder means accomplishing one or more of the following: (a) reducing the severity of the disorder; (b) limiting or preventing development of symptoms characteristic of the disorder(s) being treated; (c) inhibiting worsening of symptoms characteristic of the disorder(s) being treated; (d) limiting or preventing recurrence of the disorder(s) in patients that have previously had the disorder(s); and (e) limiting or preventing recurrence of symptoms in patients that were previously symptomatic for the disorder(s).

As used herein, “prevent”, “preventing”, “prevention”, or “prophylaxis” of a disease or disorder means preventing that a disorder occurs in a subject for a certain amount of time. For example, if a compound described herein is administered to a subject with the aim of preventing a disease or disorder, said disease or disorder is prevented from occurring at least on the day of administration and preferably also on one or more days (e.g. on 1 to 30 days; or on 2 to 28 days; or on 3 to 21 days; or on 4 to 14 days; or on 5 to 10 days) following the day of administration.

A “pharmaceutical composition” according to the invention may be present in the form of a composition, wherein the different active ingredients and diluents and/or carriers are admixed with each other, or may take the form of a combined preparation, where the active ingredients are present in partially or totally distinct form. An example for such a combination or combined preparation is a kit-of-parts.

An “effective amount” is an amount of a therapeutic agent sufficient to achieve the intended purpose. The effective amount of a given therapeutic agent will vary with factors such as the nature of the agent, the route of administration, the size and species of the animal to receive the therapeutic agent, and the purpose of the administration. The effective amount in each individual case may be determined empirically by a skilled artisan according to established methods in the art.

The term “carrier”, as used herein, refers to a diluent, adjuvant, excipient, or vehicle with which the therapeutic agent is administered. Such pharmaceutical carriers can be sterile liquids, such as saline solutions in water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like. A saline solution is a preferred carrier when the pharmaceutical composition is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatine, malt, rice flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene glycol, water, ethanol and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsions, tablets, pills, capsules, powders, sustained-release formulations and the like. The composition can be formulated as a suppository, with traditional binders and carriers such as triglycerides. The compounds of the invention can be formulated as neutral or salt forms. Pharmaceutically acceptable salts include those formed with free amino groups such as those derived from hydrochloric, phosphoric, acetic, oxalic, tartaric acids, etc., and those formed with free carboxyl groups such as those derived from sodium, potassium, ammonium, calcium, ferric hydroxides, isopropylamine, tri ethylamine, 2-ethylamino ethanol, histidine, procaine, etc. Examples of suitable pharmaceutical carriers are described in "Remington's Pharmaceutical Sciences" by E. W. Martin. Such compositions will contain a therapeutically effective amount of the compound, preferably in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the patient. The formulation should suit the mode of administration.

Embodiments of the invention

In the following paragraphs, the elements of the present invention will be described. These elements are listed with specific embodiments, however, it should be understood that they may be combined in any manner and in any number to create additional embodiments. The variously described examples and preferred embodiments should not be construed to limit the present invention to only the explicitly described embodiments. This description should be understood to support and encompass embodiments, which combine the explicitly described embodiments with any number of the disclosed and/or preferred elements. Furthermore, any permutations and combinations of all descnbed elements in this application should be considered disclosed by the description of the present application unless the context indicates otherwise.

As explained above, the present invention is further based on the observation of the present inventors that inhibitors of viral helicases and viral RNA-directed RNA polymerases (RdRp) are at least additive, preferably synergize in the inhibition of replication of single stranded positive-sense RNA viruses, most of which utilize viral helicases fortheir replication cycle. Amongst the pathogenic RNA viruses, the present invention will be most suitable for viruses including those from severe acute respiratory syndrome (SARS), middle-east respiratory syndrome (MERS), Dengue fever virus (DFV), Japanese encephalitis virus (JEV), West Nile virus (WNV). Neither retroviruses nor negative-strand viruses encode for own helicases, however the present invention in also applicable to these taxonomies as they utilize well-described hostcell helicases which could serve as drug targets for these infections. As an example, EIIV replication has been shown to depend on the human host cell DDX3 RNA helicase, which could serve as a combination therapy target in this case (Phanuphak & Gulick, 2020). Additionally, since all polymerase enzymes require single stranded substrates which are produced by helicases, the present invention applies to all polymerase classes, not only the RdRp class. Indeed, even viruses containing single stranded genetic material require helicases to separate the double stranded genetic material after the first round of replication by the polymerase.

Accordingly, the present invention features the novel combination of inhibitors, preferably small molecule inhibitors, of helicases with inhibitors, preferably small molecule inhibitors, of viral polymerases, which can advantageously be used for prevention and therapy of viral infections.

Thus, in a first aspect, the present invention relates to an inhibitor of a helicase, preferably a viral helicase for use in combination with an inhibitor of a viral polymerase in the prophylaxis or therapy of a viral infection. It will be understood by the skilled person that the inhibitor of a helicase and the inhibitor of a viral polymerase are chosen in such that they inhibit the host helicase used by a particular viral species or the viral helicase and the viral polymerase of the same species.

Furthermore, the term inhibitor of a helicase, preferably a viral helicase refers to a compound, which has an IC50 of 100 pmolar or less, preferably of 50 umolar or less, more preferably of 20 pmolar or less, even more preferably of 10 pmolar or less to inhibit the helicase activity. Suitable assay systems are well known in the art but are also described in the example section for Nspl3. Suitable assays to measure viral helicase activity and subsequent inhibition include determination of the ATP turnover rate and inhibition of this ATP turnover by means of detecting organic phosphate production from the hydrolysis of ATP to ADP using fluorescent chemicals such as malachite green. More preferably, suitable assays measur the unwinding of DNA/RNA and subsequent inhibition of this unwinding by monitoring fluorescent signal of a FRET pair or by using radiolabeled DNA/RNA with detection by scintillation.

Correspondingly, in a second aspect, the present invention relates to an inhibitor of a viral polymerase for use in combination with an inhibitor of a helicase, preferably a viral helicase in the prophylaxis or therapy of a viral infection.

Inhibitors of viral polymerases

In one embodiment of the first or second aspect of the invention, the viral polymerase is a DNA dependent RNA polymerase (dDRP or RNAP), RNA-dependent DNA polymerase (RdDp) or a RNA dependent RNA polymerase (RdRp), preferably RdRp.

In a further preferred embodiment of the first or second aspect of the invention, the viral polymerase is a RdRp, and the inhibitor of the RdRp is a nucleoside analogue or a prodrug thereof which is integrated into the viral genome upon replication.

Suitable assays to measure viral polymerase activity and subsequent inhibition include monitoring radiolabeled nucleotide incorporation into sample DNA/RNA and subsequent inhibition of this incorporation via scintillation.

A large number of inhibitors of viral polymerases have been described in the art. Some are inhibitory on the viral polymerases of several species and others are specific to a particular viral species. Due to the functional interaction between viral polymerases and helicases described by the present inventors all of these inhibitors can be used in combination therapy with the helicase inhibitors described in the art and herein. In the following examples of viral polymerases and inhibitors thereof are provided with reference to documents describing such inhibitors, the entire contents of which are incorporated herein by reference.

RdRp of Coronaviruses, in particular NSP12, have been targeted to treat or prevent Coronavirus infection. Suitable inhibitors are disclosed, e.g. in WO 2012/012776 Al, WO 2016/106050 Al, and WO 2016/144918 Al.

RdRp of Influenza has been targeted to treat or prevent influenza infection. Suitable inhibitors are disclosed, e.g. in W02015088516A1, and W02021032611A1. RdRp of Hepatitis C virus (HCV), in particular NS5B, has been targeted to treat HCV. Suitable inhibitors are disclosed, e.g. in WO 00/06529, WO 00/13708, WO 00/10573, WO 00/18231, WO 01/47883, WO 01/85172, WO 02/04425, W02004065367A1, W02006012078A2, W02006110762A2.

All of the compounds disclosed therein are suitable for practicing the combination treatment of the present invention. Particularly preferred examples of inhibitors of viral polymerases have been described in WO 2012/012776 A 1 , WO 2016/ 106050 A 1 , and WO 2016/ 144918 A 1 , the entire contents of which are incorporated herein by reference.

The present invention will be most suitable for a combination of inhibitors for the NSP12 polymerase and Nspl3 helicase in coronaviruses including those from SARS and MERS; a combination of inhibitors of NS5 polymerase and NS3 helicase in flaviviruses, including those from DFV, JEV, WNV, Zika virus, yellow fever virus, and hepatitis C virus; a combination of inhibitors of the UL5:UL52:UL8 helicase/primase complex and UL30 polymerase of herpes simplex virus; and inhibitors of the large T antigen helicase of human polyomavirus 2 in combination with inhibitors of human DNA polymerase a- pnmase and human DNA polymerase 8.

In one embodiment of the first or second aspect of the invention, the inhibitor of the viral polymerase has a structure according to formula (V):

wherein

R9 is selected from the group consisting of H, phosphate, diphosphate, and triphosphate, wherein the phosphate is optionally substituted with a (Ci-6 alkyl)-O-C(O)-CH(CH₃)-NH- group and/or with a 5-, 6- or 7-membered carbocycle (preferably phenyl), R10 is CH₃ or CN; or is a pharmaceutically acceptable salt thereof

In one embodiment of the first or second aspect of the invention, the inhibitor of the viral polymerase has a structure according to formula (VI):

wherein

R11 is selected from the group consisting of H, Ci-6 alkanoyl, phosphate, diphosphate and triphosphate, wherein phosphate is optionally substituted with a (Ci-6 alkyl)-O-C(O)-CH(CH₃)- NH- group and/or with a 5-, 6- or 7-membered carbocycle (preferably phenyl),

R12 is H or substituted N-heptylcarbamate or heptyl substituted carbonate,

Y is F or H, or is a pharmaceutically acceptable salt thereof.

In one embodiment of the first or second aspect of the invention, the inhibitor of the viral polymerase has a structure according to formula (VII):

wherein

R13 is selected from the group consisting of H, phosphate, diphosphate, and triphosphate, wherein phosphate is optionally substituted with a (Ci-g alkyl)-O-C(O)-CH(CH₃)-NH- group and/or with a 5-, 6- or 7-membered carbocycle (preferably phenyl),

R14 is H, Ci-4 alkanoyl, or 2-methyl-N-substituted propenamide, preferably R14 is H,

R15 is CH₃or C₂H,

Y is methylamine, dimethylamine, N-methylcyclopropanamine, ethyl(methyl)amine, propyl(methyl)amine, or 0, or is a pharmaceutically acceptable salt thereof.

In one embodiment of the first or second aspect of the invention, the inhibitor of a viral polymerase is a nucleoside analogue or prodrug thereof, wherein the nucleoside analogue or prodrug thereof is selected from the group consisting of deoxyadenosine analogues, in particular didanosine or vidarabine; adenosine analogues, in particular galidesivir, AT-527, or remdesivir; deoxycytidine analogues, in particular cytarabine, gemcitabine, emtricitabine, lamivudine, molnupiravir, or its initial metabolite P-d-N4- hydroxycytidine, zalcitabine; guanosine and deoxyguanosine analogues, in particular abacavir, acyclovir, or entecavir; thymidine and deoxythymidine analogues, in particular stavudine, telbivudine, or zidovudine; and deoxyuridine analogues, in particular idoxuridine or trifluridine. In preferred embodiments of the first or second aspect of the invention, the inhibitor is selected from the group consisting of AT-527, remdesivir, and molnupiravir.

Inhibitors of helicases

There are several currently identified helicase inhibitors, which span from ATP or RNA competitive, to allosteric - or even those that increase the affinity of the helicase to DNA.

ATP competitive human polyomavirus helicase inhibitors range from triple digit micromolar initial hits to triple digit nano molar after optimization. These inhibitors have been identified via a crystallographic fragment screen against VCV LTag helicase. Additionally, these inhibitors have been verified active in cellulo with EC50S as low as 260 nM. Given that the binding modes of these ATP competitive inhibitors is well characterized, it is likely that significant improvements in IC50 and EC50 are possible (Bonafoux D. et al. (2016) J. Med. Chem. 59, 15, 7138-7151.

RNA competitive helicase inhibitors have been identified to inhibit human helicase DDX3 which is required for replication ofHIV-1. These inhibitors range from double digit to single digit micromolar and are specific for the DDX3 helicase and the binding location has been hypothesized based on computational modeling with support from experimental results (Radi M. et al. (2012) Bioorganic and Medicinal Chemistry Letters 22(5):2094-2098).

Other helicase inhibitors, B1LS-179-BS and BAY 57-1293 have been shown to increase the affinity of the viral helicase complex of HSV - UL5:UL52:UL8. These small molecules prevent the enzymatic activity of the helicase by “gluing” the helicase to the DNA, preventing unwinding with potency as low as double digit nanomolar . They have additionally been shown to have activity against HSV-1 and HSV-2 in vivo (Crumpacker CS et al. (2002) Nature Medicine 8:327-328).

There exist also allosteric inhibitors of the HPV El helicase, specifically CID 515118 and CID 51 164 with IC50S of 2 micromolar and 4 nanomolar respectively. Other HPV El inhibitors, namely CHEMBL 1207306 and CID 11330698 disrupt the interaction of El and E2, with IC50S of 6 nanomolar and 20 nanomolar each (Shadrick WR et al. (2013) Journal of Biomolecular Screening 18(7):761-781).

The helicase inhibitors that may be used in the context of the present invention can follow any of the above described modality. Preferably, they are ATP or RNA competitive inhibitors and more preferably they are allosteric inhibitors. The most preferred class of allosteric inhibitors are those that allosterically inhibit Nsp 13.

Preferred non-allosteric Nsp 13 inhibitors that can be used in the first and second aspect of the invention are small molecule inhibitors that comprise or consist of a trioxa-adamantane moiety covalently bound to a pyridoxal derivative. Preferred examples of such inhibitors are bananin, iodobananin, vanillinbananin, ansabananin, eubananin, and adeninobananin.

The present inventors have identified and characterized within Nspl3 a pocket that appears to be involved in allosteric regulation of the ATPase activity of Nspl3. Compounds that specifically bind to this pocket are capable of inhibiting the ATPase activity of Nspl3. Compounds that bind to the ATPase site of ALC1 and block the ATPase activity have to compete with ATP for binding to the ATPase site. Since the cellular ATP concentration is in the range of 1 to 10 mM depending on the cellular compartment, very high binding affinities in the low nanomolar range are required to successfully prevent ATP from binding to the ATPase site of Nspl3. Allosteric inhibitors of Nspl3 do not have this limitation since they do not have to prevent ATP from binding but inhibit Nspl3 ’s ATPase activity through a different mechanism. The present inventors have identified compounds that are capable of specifically binding to the allosteric pocket and determined the spatial and electronic requirements of compounds that fit into this pocket. Thus, by defining the “lock” the inventors were able to define the “keys”, i.e. compounds, fitting into this lock, i.e. the allosteric binding pocket, and that are capable of forming non-covalent bonds or other stabilizing interactions to allow them to specifically bind in the pocket. Using this rational design approach the present inventors identified compounds that were capable of inhibiting Nspl3 movement on chromatin and which are particularly suitable to be used as helicase inhibitors in the context of the first and second aspect of the invention.

Structure-based computer modeling of ligand-protein interactions is now a core component of modern drug discovery (Charifson and Kuntz, 1997). Computational methods have played a key role in the drug discovery process for a growing number of marketed drugs, including HIV protease inhibitors (Charifson and Kuntz, 1997; Greer et al., 1994; Jorgensen, 2004) and zanamivir (an antiviral neuraminidase inhibitor) (von Itzstein et al., 1993), and in the development of new drug candidates, such as HIV integrase inhibitors (Hazuda et al., 2004; Schames et al., 2004), hepatitis C protease inhibitors (Liverton et al., 2008; Thomson and Pemi, 2006), and beta-secretase inhibitors (BACE-1) (Stauffer et al., 2007). There are three major classes of physical computer methods available in the field (listed from fastest to slowest, and least physical to most physical): (1) very fast molecular docking methods, including DOCK, Glide, AutoDock, FlexX, ICN, PMF, and GOLD, Molecular dynamics based free energy methods (MD), such as MM/GBSA or MM/PBSA, in which solvent, protein, and ligand are subject to forces exerted by each other and thermal fluctuations and move in iterative steps as a response to these forces, and (4) absolute binding free energy (ABFE) methods, including alchemical simulations, which are the most expensive computationally, but which include the physics in the most rigorous way that is currently practical. ABFE methods start from an unbound ligand and potentially the unbound structure of the protein to attempt to predict the structures, affinities, and thermal properties of the complexes of interest. These strategies known in the art and in particular the approach described in the experimental section can be used to identify compounds that are allosteric inhibitors of ALC1 by binding to the allosteric binding pocket within ALC1 first identified by the present inventors. Thus, in a preferred embodiment of the first or second aspect of the present invention, the inhibitor of a helicase activity is an inhibitor of the helicase activity of a Nspl3 helicase of SARS-CoV-2 (Nspl3) or of a viral homologue thereof, wherein the inhibitor specifically binds to an allosteric binding pocket within the N-terminal lobe of the ATPase domain of Nspl3 or of a viral homologue thereof.

The term “an inhibitor of the helicase activity” as used in the context of the inhibitors of the present invention refers to the inhibition of any helicase activity, which includes the activity of viral helicases as well as the activity of host cell helicases. In preferred embodiments, the term “an inhibitor of the helicase activity” refers to the inhibition of the activity of a helicase of a virus of the class of positive-stranded RNA viruses, preferably of the class Pisoniviricetes, more preferably of the order of Nidovirales and more preferably of the family of Coronaviridae . To assess the ability of an individual compound to inhibit helicase activity it is preferred that the helicase activity is determined in a helicase unwinding assay using SARSCoV2 helicase Nspl3 with an amino acid sequence according to SEQ ID NO: 1 as described herein. Such an assay preferably uses 0.15 nM Nspl3 and 100 nM of dsDNA that is labeled with a pair of FRET labels to detect the unwinding of the dsDNA. The unwinding reaction can be initiated by the addition of 200 pM ATP and 1 pM of unlabeled single-stranded DNA. Alternatively, the ability to inhibit helicase activity may also be determined in a helicase unwinding assay using a different helicase, such as another viral helicase or a host cell helicase. Also in these alternative assays it is preferred that the helicase is used in a concentration of 0.15 nM. It is preferred that inhibitors of the invention inhibit the helicase activity with an IC50 of 100 pM or less, more preferably with an IC50 of 50 pM or less and more preferably with an IC50 of 20 pM or less and most preferably with an IC50 of 10 pM or less.

The term “viral homologue” of SARS-CoV-2 Nspl3 with an amino acid sequence according to SEQ ID NO: 1 refers to viral proteins that are functional homologs, i.e. that exhibit helicase activity in a chromatin remodeling assay as used in the examples of the present invention (see Example 3). Preferably, the term refers to a protein that is a functional and structural homologue of SARS-CoV-2 Nspl3. The structural homology is preferably within the amino acids of the viral homologue that form the allosteric pocket of the helicase. The present inventors have used molecular dynamics (MD) simulation on the first lobe of the SARS-CoV-1 Nspl3 helicase (residues 236 to 440 from the published SARS-CoV-1 Nspl3 PDB: 6IYT, see Example 1) to identify a yet unidentified allosteric binding pocket within Nspl3. The allosteric binding pocket to which the helicase inhibitors of the present invention bind is formed by amino acids 236 to 440 ofNspl3 according to SEQ ID NO: 1. However, not every amino acid within the amino acid stretch spanning amino acid residues 236 to 440 of SEQ ID NO: 1 is forming the surface of the allosteric pocket of Nspl3 available for binding to the inhibitors of the invention. This is due to the fact that some amino acids are buried in the pocket and are poorly accessible and others are not even part of the pocket but are located within Nspl3 or on the outside surface of Nspl3. The surface area of this allosteric binding pocket of Nspl3 is formed by the following amino acids (with reference to SEQ ID NO: 1): Y277, T279, L280, Q281, G282, T307, C309, F373, D374, E375, 1376, S377, M378, A379, L384, N388, Y396, Y398, 1399, G400, D401, P406, P408, N423, V425, C426, R427, and M429. Of these residues amino acids Y277, L384, N388, Y396, Y398, and V425 form the entry channel into the pocket through which the inhibitors of the invention may enter the binding pocket, and amino acids T307, C309, F373, D374, E375, S377, M378, A379, and N423 form the left channel and T279, L280, Q281, G282, 1376, 1399, G400, D401, P406, P408, C426, R427, and M429 form the right channel. Thus, preferred viral homologues comprise a binding pocket of similar structure, which can be assessed by using MD as described below. Preferred structural homologues are those that comprise identical or conservatively or semi-conservatively substituted amino acids at at least 50% of the amino acid positions corresponding to Y277, T279, L280, Q281, G282, T307, C309, F373, D374, E375, 1376, S377, M378, A379, L384, N388, Y396, Y398, 1399, G400, D401, P406, P408, N423, V425, C426, R427, and M429 of Nspl3 with an amino acid sequence according to SEQ ID NO: 1. Preferred structural homologues comprise identical or conservatively substituted amino acids at at least 60%, 70%, 80% of the amino acid positions corresponding to Y277, T279, L280, Q281, G282, T307, C309, F373, D374, E375, 1376, S377, M378, A379, L384, N388, Y396, Y398, 1399, G400, D401, P406, P408, N423, V425, C426, R427, and M429 of Nspl3 with an amino acid sequence according to SEQ ID NO: 1. Particularly preferred structural viral helicase homologues share at least 60%, at least 70%, more preferably at least 80%, more preferably at least 90% with AA 277 to M429 ofNspl3 with an amino acid sequence according to SEQ ID NO: 1. Exemplary preferred viral homologues of SARS-CoV-2 Nspl3 are shown in Fig. 3 and are depicted in the appended sequence listing as SEQ ID NOs: 2 to 7.

The term “corresponding position” is used in the context of the present invention to refer to an amino acid position within the amino acid sequence of a given protein (e g. a helicase homologue of Nspl3 according to SEQ ID NO: 1), which is aligned with a reference protein, in particular with Nspl3 of SARSCoV2 according to SEQ ID NO: 1, that aligns with an amino acid in the reference protein. Alignments of two or more amino acids sequences can be carried out using a number of publicly available software tools including Clustal Omega (https://www.ebi.ac.uk/Tools/msa/clustalo/) or PBLAST in each case using standard alignment parameters. An example of such an alignment using Nspl3 of SARSCoV2 according to SEQ ID NO: 1 and helicases of six related RNA viruses are shown in Fig. 3. The skilled person can readily determine on the basis of such an alignment an amino acid that corresponds to one of the amino acids specifically indicated above and below with reference to Nspl3 of SARSCoV2 according to SEQ ID NO: 1. For example, with 11 of SARSCoV2 aligns with 1278 of SARSCoV (SEQ ID NO: 2) referred to as “229E” in figure 3, with 1278 of Nspl3 helicase of HCoV-NL63 (SEQ ID NO: 3) referred to as “NL- 63” in figure 3, with Y276 of Nspl3 helicase of EICoV OC43 (SEQ ID NO: 4) referred to as “OC43” in figure 3, with Y276 of Nspl3 helicase of HCoV HKU1 (SEQ ID NO: 5) referred to as “HKU1” in figure , with Y277 ofNspl3 helicase of MERS CoV (SEQ ID NO: 6), and with Y277 ofNsp!3 helicase of SARS CoV (SEQ ID NO: 7).

Accordingly, in one embodiment of the first or second aspect,

(i) the N-terminal lobe of the ATPase domain consists of amino acid residues 236 to 440 of SEQ ID NO: 1 or the corresponding amino acid residues of the viral homologue; and/or (ii) the allosteric binding pocket comprises or consists of Y277, T279, L280, Q281, G282, T307, C309, F373, D374, E375, 1376, S377, M378, A379, L384, N388, Y396, Y398, 1399, G400, D401, P406, P408, N423, V425, T426, R427, and M429 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue ofNspl3. These are the amino acids that can form non-covalent bonds with the inhibitor of the present invention because their side chains and/or back bones form the surface of the binding pocket.

In a further embodiment of the first or second aspect, the allosteric binding pocket is tripartite and comprises an entry channel (1), a left channel (2) and a right channel (3) and is located on the backside of the active site of Nspl3 or of a viral homologue thereof. It can be seen in Fig. 5 to 7, and 10. An allosteric inhibitor of the invention specifically binds, preferably non-covalently, to amino acids within one or more of the entry channel (1), the left channel (2), and the right channel (3) and, thereby inhibits allosteric activation of the helicase.

In a further embodiment of the first or second aspect, the helicase inhibitor specifically binds to at least one of the following seven sets of amino acids within the allosteric binding pocket:

(i) in the entry channel the backbone of at least one amino acid residues selected from N381, L384, S385, V387, N388, and V425 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the ammo acids at the corresponding positions in a viral homologue of Nsp 13 and/or one or more sidechains of amino acid residues selected from P238, T239, Y277, N381, L384, S385, V387, N388, Y396, Y398, N 423, and V425 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nsp 13;

(ii) in the right channel the backbone of at least one amino acid residues selected from L280, T279, Q281, G282, T307, C309, F373, Y398, 1399, G400, D401, P406, P408, V425, C426, and R427 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nsp 13 and/or one or more side chains of amino acid residues selected from L280, Q281, F373, 1376, 1399, G400, P406, P408, N423, C426, and M429 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3;

(iii) in the left channel the backbone of amino acid residues selected from T279, E375, 1376, S377, M378, A379, P408, and M429 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nsp 13 and/or one or more sidechains of amino acid residues selected from T307, C309, F373, D374, 1376, M378, A379, L384, and N423 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nsp 13;

(iv) in the right and entry channel the backbone of at least one amino acid residue selected from L280, T279, Q281, G282, T307, C309, F373, N381, L384, S385, V387, N388, Y398, 1399, G400, D401, P406, P408, V425, C426, and R427 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue ofNspl3 and/or one or more sidechains of amino acid residues selected from P238, T239, Y277, L280, Q281, F373, 1376, N381, L384, S385, V387, N388, Y396, Y398, 1399, G400, P406, P408, N423, V425, C426, and M429 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue ofNsp!3;

(v) in the left and entry channel the backbone of amino acid residues selected from T279, E375, 1376, S377, M378, A379, N381, L384, S385, V387, N388, P408, V425, and M429 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3 and/or one or more sidechains of amino acid residues selected from P238, T239, Y277, T307, C309, F373, D374, 1376, M378, A379, N381, L384, S385, V387, N388, Y396, Y398, N423, and V425 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue ofNsp!3;

(vi) in the left and right channel the backbone of amino acid residues selected from T279, L280, Q281, G282, T307, C309, F373, E375, 1376, S377, M378, A379, Y398, 1399, G400, D401, P406, P408, V425, C426, R427, M429 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3 and/or one or more sidechains of amino acid residues selected from L280, Q281, T307, C309, F373, D374, 1376, M378, A379, L384, 1399, G400, P406, P408, N423, C426, and M429 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3; and/or

(vii) in the left, right and entry channel the backbone of amino acid residues selected from T279, L280, Q281, G282, T307, C309, F373, E375, 1376, S377, M378, A379, N381, L384, S385, V387, N388, Y398, 1399, G400, D401, P406, P408, V425, C426, R427, and M429 ofNsp!3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3 and sidechains of residues P238, T239, Y277, L280, Q281, T307, C309, F373, D374, 1376, M378, A379, N381, L384, S385, V387, N388, Y396, Y398, 1399, G400, P406, P408, N423, V425, C426, and M429 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue ofNsp!3.

In a further embodiment of the first or second aspect, the helicase inhibitor specifically binds to:

(a) the amino acids indicated above in (i) and further to one more amino acids selected from the group consisting of Y277 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y277 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents, or wherein the inhibitor binds to Y277 by cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents; or wherein the terminal oxygen of Y277 interacts with a hydrogen bond donating group; N388 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to a side chain on N388 via a hydrogen bond donating or accepting group; Y396 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y396 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents, or wherein Y396 forms cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents; and Y398 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitors binds to the aromatic ring of Y398 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents or forms cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents;

(b) the amino acids indicated above in (ii) and further to one more amino acids selected from the group consisting of L280 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of L280 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3 with a hydrogen bond acceptor group; Y398 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y398 via face-to-face or edge-to- face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen- pi interactions with polar, charged, or carbo-halogen substituents; 1399 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of 1399 by carbo halogen or hydrogen bond donating groups or to the backbone N of 1399 interacting with a hydrogen bond acceptor; G400 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the ammo acids at the corresponding positions in a viral homologue ofNspl3, wherein the inhibitor binds to the backbone N of G400 with a hydrogen bond acceptor group or to the backbone carbonyl oxygen of G400 with carbo halogen or hydrogen bond donating groups; D401 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of D401 with carbo halogen or hydrogen bond donating groups; P406, wherein the inhibitor binds to the backbone carbonyl oxygen of P406 with carbo halogen or hydrogen bond donating groups; and C426 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the S of C426 with a carbo-halogen group or the S of C426 forms a covalent bond to a “warhead” of the inhibitor;

(c) the amino acids indicated above in (iii) and further to one more amino acids selected from the group consisting of T307 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the sidechain of T307 with a hydrogen bond donating or accepting group or wherein the inhibitor binds to the backbone carbonyl oxygen of T307 with carbo halogens or hydrogen bond donating groups; F373 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of F373 via face-to-face or edge-to- face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen- pi interactions with polar, charged, or carbo-halogen substituents; C309 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the S of C309 with carbo-halogens or the S of C309 forms a covalent bond to a “warhead” of the inhibitor; D374 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or ofthe amino acids at the corresponding positions in a viral homologue of Nsp 13, wherein the inhibitor binds to the sidechain of D374 with a hydrogen bond donating or accepting group; E375 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of E375 with carbo halogens or hydrogen bond donating groups; 1376 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of 1376 with carbo halogens or hydrogen bond donating groups; M378 ofNsp!3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nsp 13, wherein the inhibitor binds to the backbone N of M378 with a hydrogen bond acceptor group; and A379 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of A379 with carbo halogens or hydrogen bond donating groups or to the backbone N of A379 with a hydrogen bond acceptor group;

(d) the amino acids indicated above in (iv) and further to one more amino acids selected from the group consisting of Y277 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y277 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents or wherein the inhibitor binds to the terminal oxygen of Y277 with a hydrogen bond donating group; L280 of Nsp 13 of S ARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of L280 with a hydrogen bond acceptor group; N388 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nsp 13, wherein the inhibitor binds to the side chain ofN388 with a hydrogen bond donating or accepting group; Y396 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y396 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents; Y398 of Nsp 13 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y398 via face-to-face or edge-to-face pi-pi interaction with aromatic carboor heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents; 1399 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of 1399 with carbo halogen or hydrogen bond donating groups or to the backbone N of 1399 with a hydrogen bond acceptor group; G400 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of G400 with a hydrogen bond acceptor group or to the backbone carbonyl oxygen of G400 with carbo halogen or hydrogen bond donating groups; D401 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of D401 with carbo halogen or hydrogen bond donating groups; P406 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of P406 with carbo halogen or hydrogen bond donating groups; and C426 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the S of C426 with a carbo-halogen or the S of 426 forms a covalent bond to a “warhead” of the inhibitor;

(e) the amino acids indicated above in (v) and further to one more amino acids selected from the group consisting of: Y277 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y277 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents or wherein the inhibitor binds to the terminal oxygen of Y277 with a hydrogen bond donating group; N388 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the side chain of N388 with a hydrogen bond donating or accepting group; T307 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the sidechain of T307 with a hydrogen bond donating or accepting group or to the backbone carbonyl oxygen of T307 with carbo halogens or hydrogen bond donating groups; F373 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of F373 via face-to-face or edge-to- face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen- pi interactions with polar, charged, or carbo-halogen substituents; C309 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the S of C309 with carbo-halogens or the S of C309 forms a covalent bond to a “warhead” of the inhibitor; D374 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or ofthe amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the sidechain of D374 with a hydrogen bond donating or accepting group; E375 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of E375 with carbo halogens or hydrogen bond donating groups; 1376, wherein the inhibitor binds to the backbone carbonyl oxygen of 1376 with carbo halogens or hydrogen bond donating groups; M378 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of M378 with a hydrogen bond acceptor group; A379 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of A379 with carbo halogens or hydrogen bond donating groups or to the backbone N of A379 with a hydrogen bond acceptor group; Y396, of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3 wherein the inhibitor binds to the aromatic ring of Y396 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents; and Y398 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in aviral homologue ofNspl3, wherein the inhibitor binds to the aromatic ring ofY398 via face- to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents;

(f) the amino acids indicated above in (vi) and further to one more amino acids selected from the group consisting of L280 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of L280 with a hydrogen bond acceptor group; T307 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the sidechain of T307 with a hydrogen bond donating or accepting group or to the backbone carbonyl oxygen of T307 with carbo halogens or hydrogen bond donating groups; F373 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the ammo acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of F373 via face-to-face or edge-to- face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen- pi interactions with polar, charged, or carbo-halogen substituents; C309, wherein the inhibitor binds to the S of C309 with carbo-halogens or the S of C309 forms a covalent bond to a “warhead” of the inhibitor; D374 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the sidechain of D374 with a hydrogen bond donating or accepting group; E375, wherein the inhibitor binds to the backbone carbonyl oxygen of E375 with carbo halogens or hydrogen bond donating groups; 1376 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of 1376 with carbo halogens or hydrogen bond donating groups; M378 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of M378 with a hydrogen bond acceptor group; A379 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of A379 with carbo halogens or hydrogen bond donating groups or to the backbone N of A379 with a hydrogen bond acceptor group; Y398 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y398 via face-to-face or edge-to- face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen- pi interactions with polar, charged, or carbo-halogen substituents; 1399 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of 1399 with carbo halogen or hydrogen bond donating groups or to the backbone N of 1399 with a hydrogen bond acceptor group; G400 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue ofNspl3, wherein the inhibitor binds to the backbone N of G400 with a hydrogen bond acceptor group or to the backbone carbonyl oxygen of G400 with carbo halogen or hydrogen bond donating groups; D401 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of D401 with carbo halogen or hydrogen bond donating groups; P406, wherein the inhibitor binds to the backbone carbonyl oxygen of P406 with carbo halogen or hydrogen bond donating groups; and C426 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the S of C426 with a carbo-halogen or the S of 426 forms a covalent bond to a “warhead” of the inhibitor; or

(g) the amino acids indicated above in (vii) and further to one more amino acids selected from the group consisting of Y277 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y277 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents or wherein the inhibitor binds to the terminal oxygen of Y277 with a hydrogen bond donating group; N388 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the side chain of N388 with a hydrogen bond donating or accepting group; Y396 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y396 via face-to-face or edge-to-face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents; L280 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of L280 with a hydrogen bond acceptor group; T307 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the sidechain of T307 with a hydrogen bond donating or accepting group or to the backbone carbonyl oxygen of T307 with carbo halogens or hydrogen bond donating groups; F373 ofNsp!3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of F373 via face-to-face or edge-to- face pi-pi interaction with aromatic carbo- or heterocyclic substituents or via cation-pi, polar-pi, or halogen- pi interactions with polar, charged, or carbo-halogen substituents; C309 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the S of C309 with carbo-halogens or the S of C309 forms a covalent bond to a “warhead” of the inhibitor; D374 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or ofthe amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the sidechain of D374 with a hydrogen bond donating or accepting group; E375 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of E375 with carbo halogens or hydrogen bond donating groups; 1376 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of 1376 with carbo halogens or hydrogen bond donating groups; M378 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of M378 with a hydrogen bond acceptor group; A379 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of A379 with carbo halogens or hydrogen bond donating groups or to the backbone N of A379 with a hydrogen bond acceptor group; Y398 ofNspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the aromatic ring of Y398 via face-to-face or edge-to-face pi-pi interaction with aromatic carboor heterocyclic substituents or via cation-pi, polar-pi, or halogen-pi interactions with polar, charged, or carbo-halogen substituents; 1399 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of 1399 with carbo halogen or hydrogen bond donating groups or to the backbone N of 1399 with a hydrogen bond acceptor group; G400 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone N of G400 with a hydrogen bond acceptor group or to the backbone carbonyl oxygen of G400 with carbo halogen or hydrogen bond donating groups; D401 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of D401 with carbo halogen or hydrogen bond donating groups; P406 of Nspl3 of SARSCoV2 according to SEQ ID NO: 1 or of the amino acids at the corresponding positions in a viral homologue of Nspl3, wherein the inhibitor binds to the backbone carbonyl oxygen of P406 with carbo halogen or hydrogen bond donating groups; and C426, wherein the inhibitor binds to the S of C426 with a carbo-halogen or the S of 426 forms a covalent bond to a “warhead” of the inhibitor.

The skilled person using a 3D model of Nspl3 or a homolog thereof or at least a 3D model of the binding pocket and in silico modelling can determine chemical groups that are capable of forming the above indicated bonds with the above indicated amino acids or chemical groups within the above indicated amino acids of the binding pocket (see also Example 1).

In one embodiment of the first or second aspect, the helicase inhibitor is an small molecule inhibitor with a molecular weight within the range of 200 - 700 Da.

In one embodiment of the first or second aspect, the helicase inhibitor has a structure and stereoelectronic properties complementary to the allosteric binding pocket of the helicase. A structure of an inhibitor is considered complementary, if it can enter the binding pocket of the helicase and fit into the tripartite structure of the binding pocket. An example of an inhibitor that has a structure and stereoelectronic properties complementary to the allosteric binding pocket and which thus fits into the binding pocket is shown in Fig. 7. The position of exemplary compounds that have a structure and stereoelectronic properties complementary to the allosteric binding pocket are also shown in Fig. 9. Fig. 11 is an 2D view of the binding pocket and shows how the three different compounds interact with amino acids in the binding pocket.

In one embodiment of the first or second aspect, the helicase inhibitor consists of a central acyclic or cyclic core structure with 1 - 3 substituents that are independently directed at one, two or three of the channels selected from the group of entry channel, the left channel and a right channel of the tripartic allosteric binding pocket. The phrase a “substituent is directed at a channel” is used in the context of the present invention to characterize a substituent that protrudes into that channel and forms a non-covalent bond with at least one amino acid within the channel.

In a further embodiment of the first or second aspect, the helicase inhibitor consists of a central heterocyclic or carbocyclic scaffold optionally substituted with 1 - 3 substituents that are independently directed at one, two or three of the channels selected from the group of entry channel, the left channel and a right channel of the tripartic allosteric binding pocket.

In a further embodiment of the first or second aspect, the helicase inhibitor consists of a central heteroaromatic scaffold optionally substituted with 1- 3 substituents that are independently directed at one, two or three of the channels selected from the group of entry channel, the left channel and a right channel of the tripartic allosteric binding pocket.

In a further embodiment of the first or second aspect, the helicase inhibitor consists of a central heteroaromatic scaffold optionally substituted with 2 or 3 substituents, preferentially 3 substituents that are independently directed at one, two or three of the channels selected from the group of entry channel, the left channel and a right channel of the tripartic allosteric binding pocket.

In a further embodiment of the first or second aspect, the helicase inhibitor consists of a central heteroaromatic scaffold comprising 1 to 3 5-, 6- or 7-membered rings, wherein 0 to 2 of the individual rings are selected from 5-, 6- or 7-membered carbocyclic rings and from 1 to 3 rings are selected from 5-, 6- or 7-membered heterocyclic rings, wherein each ring is annulated to at least one other ring and/or connected to at least one other ring via covalent bonds, and wherein the heteroaromatic scaffold is optionally substituted with 2 or 3 substituents, preferably 3 substituents that are independently directed at one, two or three of the channels selected from the group of entry channel, the left channel and a right channel of the tripartic allosteric binding pocket.

In a particular embodiment of the first or second aspect, the 5-, 6- or 7-membered heterocyclic ring is selected from the group consisting of imidazole, imidazoline, pyrazole, pyrazolone, pyrrole, 2- hydroxypyrrole, 1,2,3-triazole, thiophene, 1,2,4-thiadiazole, quinazoline, 1-quinoline, 3-quinoline, pyrrolopyridine, imidazopyridine, and pyrimidopyrimidine.

In a particular embodiment of the first or second aspect, the helicase inhibitor of the invention has a structure according to formula (I): ENTRY CHANNEL

LEFT CHANNEL > RIGHT CHANNEL

(I) wherein

Al and A3 are each independently selected from N or C;

A2 is selected from N, C or 0;

X is H or OH or NH₂;

LI is selected from the group consisting of C, CH, CH₂, O, N, and NH; or LI is not present;

Z is a 5-, 6- or 7-membered carbo- or heterocycle substituted with R3, optionally further substituted, wherein R3 is connected to Z either via a bond or via a -CH₂- group;

R1 is H or a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -N0₂, -CN, -OH, -C00H, -NH-SO₂-alkyl (particularly -NH-SO₂-(Ci-C6)alkyl), NH- CO-alkyl (particularly -NH-C0-(Ci-C6)alkyl), -C0NH₂, -CONH-alkyl (particularly -C0NH-(Ci- Ce)alkyl), -Br, -Cl, -F, -I, -Me, -CF₂, -Et, -OMe, and -SMe;

R2 is H or a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two or three (preferably one) lipophilic substituents that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, -Me, -CFs, -Et, -OMe, and -SMe, wherein R2 is connected to A3 either via a bond or via a -CH₂- group;

R3 is H or a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -N0₂, -CN, -OH, -C00H, -NH-SO₂-alkyl (particularly -NH-SO₂-(Ci-Ce)alkyl), NH- CO-alkyl (particularly -NH-CO-(Ci-C₆)alkyl), -C0NH₂, -CONH-alkyl (particularly -C0NH-(Ci- C₆)alkyl), -Br, -Cl, -F, -I, -Me, -CF₃, -Et, -OMe, and -SMe; or pharmaceutically acceptable salt thereof, wherein Rl, R2 and R3 preferably have a molecular shape and stereoelectronic properties complementary to the allosteric binding pocket.

In above formula (I) the “Entry Channel”, “Left Channel” and “Right Channel” are merely indicated to indicate the relative position that the inhibitor of the invention will occupy when bound to the binding pocket. The indicating of the position of the three channels aids the skilled person in selecting suitable substituents from the above indicated substituents that can bind to the amino acids within the respectively indicated part of the binding pocket. Thus, in a further embodiment of the first or second aspect Rl is selected in such that it binds to amino acids in the Entry Chanel, R2 is selected in such that it binds to amino acids in the Left Channel and R3 is selected in such that it binds to amino acids in the Right Channel.

In above embodiment it is preferred that

Al is N substituted with R1.

In above embodiment it is preferred that

A2 is N.

In above embodiment it is preferred that

A3 is C substituted with R2, wherein R2 is connected to A3 either via a bond or via a -CH₂- group.

In above embodiment it is preferred that

LI is CH= or CH2 connected to Z.

In above embodiment it is preferred that

Z is a 5-, 6-membered heterocycle substituted with R3, optionally further substituted, preferably with one or two =0 or -NH₂, more preferably with one or two =0; wherein R3 is connected to Z either via a bond or via a -CH₂- group is a 5- membered heterocycle, preferably 5-membered heteroaryl substituted with R3, optionally fiirther substituted, wherein R3 is connected to Z either via a bond or via a — CH₂— group, preferably via a -CH₂- group. Particularly preferred 5 -membered heteroaryls are selected from the group consisting of furanyl, thiophenyl, oxazolyl, isoxazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, pyrrolyl, imidazolyl, pyrazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, thiazolyl, isothiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, optionally further substituted, wherein R3 is connected to Z either via a bond or via a -CH₂- group. The 5 membered heteroaryl may be further substituted with one or two =0 or -NH₂, more preferably with one or two =0. In a further preferred embodiment Z is a 5-membered N-heteroaryl, preferably imidazolyl, selected from pyrrolyl, imidazolyl, pyrazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, preferably optionally further substituted, preferably with one or two =0 or -NH₂, more preferably with one or two =0. In the most preferred embodiment Z is imidazolidine-2,4-dionyl. wherein R3 is connected to the imidazolidine-2,4-dionyl at the N at position 3 via a -CH₂- group.

In above embodiment it is preferred that

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -N0₂, -CN, -OH, -C00H, -NH-SO₂-alkyl (particularly -NH-SO₂-(Ci-C6)alkyl), NH- CO-alkyl (particularly -NH-C0-(Ci-C6)alkyl), -C0NH₂, -CONH-alkyl (particularly -C0NH-(Ci- Ce)alkyl), -Br, -Cl, -E, -I, -Me, -CF₂, -Et, -OMe, and -SMe. More preferably R1 is a 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -N0₂, -CN, -OH, -C00H, -NH- SO₂-aIkyl (particularly -NH-SO₂-(Ci-C6)alkyl), NH-CO-alkyl (particularly -NH-CO-(Ci-Cs)alkyl), - CONH2, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, -Me, -CF₃, -Et, -OMe, and -SMe.

In above embodiment it is preferred that 31

R2 is a 6-membered aryl or a 5- or 6-membered heteroaryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe. More preferably R2 is a 6- membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, - CF3, Et, -OMe, and -SMe. If R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, - OMe, and -SMe is in para position. If R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe are in ortho and para position.

In above embodiment it is preferred that

R3 is a 6-membered aryl or a 5 - or 6-membered heteroaryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-Cg)alkyl), NH- CO-alkyl (particularly -NH-CO-(Ci-C₆)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci- Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe. More preferably R1 is a 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of NO2, -CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-Ce)alkyl), NH-CO-alkyl (particularly -NH-CO-(Ci-Ce)alkyl), -CONH₂, - CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe.

In a further embodiment of the first or second aspect, the helicase inhibitor has a structure according to formula (I), wherein

Al is N substituted with R1 ;

A2 is N; and

A3 is C substituted with R2, wherein R2 is connected to A3 either via a bond or via a -CH₂- group.

In above embodiment it is preferred that:

X is H or OH.

In above embodiment it is preferred that:

LI is CH= or CH₂ connected to Z.

In above embodiment it is preferred that:

Z is a 5- or 6-membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH2- group.

In above embodiment it is preferred that:

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-Cg)alkyl), NH- CO-alkyl (particularly -NH-CO-(Ci-C6)alkyl), -CONH2, -CONH-alkyl (particularly -CONH-(Ci- C₆)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe. In above embodiment it is preferred that:

R2 is a 6-membered aryl or a 5 - or 6-membered heteroaryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe are preferably in ortho and para position.

In above embodiment it is preferred that:

R3 is a 6-membered aryl or a 5 - or 6-membered heteroaryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-Cg)alkyl), NH- CO-alkyl (particularly -NH-CO-(Ci-Ce)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci- C₆)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

X is H or OH; and

LI is CH= or CH₂ connected to Z.

In above embodiment it is preferred that:

X is H or OH;

LI is CH= or CH₂ connected to Z; and

Z is a 5- or 6-membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH₂- group.

In above embodiment it is preferred that:

X is H or OH;

LI is CH= or CH₂ connected to Z; and

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-C6)alkyl), NH-CO-alkyl (particularly -NH- CO-(Ci-Cs)alkyl), -CONH2, -CONH-alkyl (particularly -CONH-(Ci-C6)alkyl), -Br, -Cl, -F, -I, Me, - CF3, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

X is H or OH;

LI is CH= or CH2 connected to Z; and

R2 is 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, - F, -I, Me, -CF₃, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe are preferably in ortho and para position. In above embodiment it is preferred that:

X is H or OH;

LI is CH= or CH2 connected to Z; and

R3 is 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SOz-alkyl (particularly -NH-SO₃-(C -C,)alkyl). NH-CO-alkyl (particularly -NH- CO-(Ci-Cg)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, - CF₃, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

X is H or OH;

LI is CH= or CH₂ connected to Z;

Z is a 5- or 6-membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH₂- group; and

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -NO₂, -CN, -OH, -COOH, -NH-SO₂-alkyl (particularly -NH-SO₂-(Ci-C6)alkyl), NH-CO-alkyl (particularly -NH- CO-(Ci-Cs)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, - CF₃, Et, -OMe, and -SMe;

In above embodiment it is preferred that:

X is H or OH;

LI is CH= or CH₂ connected to Z;

Z is a 5- or 6-membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH₂- group; and

R2 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three (preferably one) lipophilic substituents that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, - F, -I, Me, -CF₃, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe are preferably in ortho and para position; and

In above embodiment it is preferred that:

X is H or OH;

LI is CH= or CH2 connected to Z;

Z is a 5- or 6-membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH₂- group; and

R3 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SOz-alkyl (particularly -NH-SO₂-(C -C )alkyl). NH-CO-alkyl (particularly -NH- CO-(Ci-Cg)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, - CF₃, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

Al is N substituted with R1 ;

A2 is N;

A3 is C substituted with R2, wherein R2 is connected to A3 either via a bond or via a -CH₂- group;

X is H or OH;

LI is CH= or CH₂ connected to Z;

Z is a 5- or 6-membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH₂- group;

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SO₂-alkyl (particularly -NH-SO₂-(Ci-C6)alkyl), NH-CO-alkyl (particularly -NH- CO-(Ci-Cs)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci-C6)alkyl), -Br, -Cl, -F, -I, -Me, -CF₃, -Et, -OMe, and -SMe;

R2 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three (preferably one) lipophilic substituents that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CFj, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, - F, -I, Me, -CF3, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe are preferably in ortho and para position; and

R3 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-C6)alkyl), NH-CO-alkyl (particularly -NH- CO-(Ci-Cs)alkyl), -CONH2, -CONH-alkyl (particularly -CONH-(Ci-C6)alkyl), -Br, -Cl, -F, -I, Me, - CF₃, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

Al is N substituted with R1 ;

A2 is N;

A3 is C substituted with R2, wherein R2 is connected to A3 either via a bond or via a -CH2- group;

X is H or OH;

LI is CH= or CH2 connected to Z;

Z is a 5 -membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a — CH₂— group;

R1 is a 6-membered aryl or heteroaryl, preferably 6-membered aryl, optionally substituted with one or two, preferably one substituents that are independently from each other selected from the group consisting of -NO₂, -CN, -OH, -COOH, -NH-SO₂-alkyl (particularly -NH-SO₂-(Ci-C₆)alkyl), NH- CO-alkyl (particularly -NH-CO-(Ci-Ce)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci- C₆)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe;

R2 is a 6-membered aryl or heteroaryl, preferably 6-membered aryl, optionally substituted with one or two lipophilic substituents that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, - F, -I, Me, -CF₃, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe are preferably in ortho and para position; and

R3 is a 6-membered aryl or heteroaryl, preferably 6-membered aryl, optionally substituted with one or two (preferably one) substituents that are independently from each other selected from the group consisting of -NO₂, -CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-Cs)alkyl), NH- CO-alkyl (particularly -NH-CO-(Ci-C6)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci- C₆)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (I), wherein Al is N substituted with Ri;

A2 is N; and

A3 is C substituted with R₂, wherein R2 is connected to A3 either via a bond or via a -CH₂- group.

In above embodiment it is preferred that:

X is H or OH.

In above embodiment it is preferred that: LI is CH= connected to Z.

In above embodiment it is preferred that:

Z is a 5 -membered heterocycle, preferably a 5 -membered heteroaryl, more preferably a 5 -membered N-heteroaryl, substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH2- group, preferably via a -CH2- group.

In above embodiment it is preferred that:

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, - CN, -OH, COOH, NH-SO2-alkyl (particularly -NH-SO2-(Ci-Ce)alkyl), NH-CO-alkyl (particularly - NH-CO-(Ci-Ce)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

R2 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, - OMe, and -SMe are preferably in ortho and para position.

In above embodiment it is preferred that:

R3 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, - CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-C6)alkyl), NH-CO-alkyl (particularly -NH-CO-(Ci-Ce)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, wherein R3 is connected to Z via a -CH₂- group.

In above embodiment it is preferred that:

X is H or OH; and

LI is CH= connected to Z.

In above embodiment it is preferred that:

X is H or OH;

LI is CH= connected to Z; and

Z is a 5- membered heterocycle, preferably 5 -membered N-heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH2- group, preferably via a -CH2- group.

In above embodiment it is preferred that:

X is H or OH; LI is CH= connected to Z;

Z is a 5- membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH2- group; and

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, - CN, -OH, COOH, NH-SO2-alkyl (particularly -NH-SO2-(Ci-Cs)alkyl), NH-CO-alkyl (particularly - NH-CO-(Ci-Ce)alkyl), -CONH2, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe;

In above embodiment it is preferred that:

X is H or OH;

LI is CH= connected to Z;

Z is a 5- membered heterocycle, preferably 5 -membered N-heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH₂- group; and

R2 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, - OMe, and -SMe are preferably in ortho and para position; and

In above embodiment it is preferred that:

X is H or OH;

LI is CH= connected to Z;

Z is a 5- membered heterocycle, preferably 5-membered N-heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH₂- group, preferably via a -CH₂- group; and

R3 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO₂, - CN, -OH, -COOH, -NH-SO₂-alkyl (particularly -NH-SO₂-(Ci-C6)alkyl), NH-CO-alkyl (particularly -NH-CO-(Ci-C6)alkyl), -CONH2, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, wherein R3 is connected to Z via a -CH2- group.

In above embodiment it is preferred that:

Al is N substituted with Ri;

A2 is N;

A3 is C substituted with R₂, wherein R2 is connected to A3 either via a bond or via a -CH₂- group;

X is H or OH; LI is CH= connected to Z;

Z is a 5- membered heterocycle, preferably 5-membered N-heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH2- group, preferably via a -CH2- group;

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, - CN, -OH, COOH, NH-SO2-alkyl (particularly -NH-SO2-(Ci-Cs)alkyl), NH-CO-alkyl (particularly - NH-CO-(Ci-Ce)alkyl), -CONH2, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe;

R2 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, - OMe, and -SMe are preferably in ortho and para position; and

R3 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, - CN, -OH, -COOH, -NH-SO2-alkyl (particularly -NH-SO2-(Ci-C6)alkyl), NH-CO-alkyl (particularly -NH-CO-(Ci-Ce)alkyl), -CONH₂, -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, wherein R3 is connected to Z via a -CH₂- group.

In above embodiment it is preferred that:

Al is N substituted with Ri;

A2 is N;

A3 is C substituted with R₂, wherein R2 is connected to A3 either via a bond or via a -CH₂- group.

X is H or OH;

LI is CH= connected to Z;

Z is a 5- membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a -CH2- group, preferably via a -CH2- group;

Rl is a 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, -CN, -OH, COOH, NH-SO2-alkyl (particularly -NH-SO2-(CI- Cs)alkyl), NH-CO-alkyl (particularly -NH-CO-(Ci-Cs)alkyl), -CONH2, -CONH-alkyl (particularly - CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe;

R2 is a 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, - F, -I, Me, -CF3, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe are preferably in ortho and para position; and

R3 is a 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one substituent(s) that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SOj-alkyl (particularly -NH-SO₂-(Ci- Ce)alkyl), NH-CO-alkyl (particularly -NH-CO-(Ci-Ce)alkyl), -CONH2, -CONH-alkyl (particularly - CONH-(Ci-Ce)alkyl), -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, wherein R3 is connected to Z via a — CH₂- group.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (I), wherein Al is N substituted with Ri;

A2 is N;

A3 is C substituted with R₂, wherein R2 is connected to A3 either via a bond or via a -CH₂- group;

X is OH;

LI is CH= connected to Z;

Z is a 5 -membered heterocycle substituted with R3, wherein R3 is connected to Z either via a bond or via a — CH₂— group;

Rl is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one polar substituent(s) that are independently from each other selected from the group consisting of -NO₂, - CN, -OH, COOH, NH-SO₂-alkyl (particularly -NH-SO₂-(Ci-C6)alkyl), NH-CO-alkyl (particularly - NH-CO-(Ci-C6)alkyl), -CONH₂, and -CONH-alkyl (particularly -CONH-(Ci-Ce)alkyl);

R2 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, - F, -I, Me, -CF3, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of-Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe are preferably in ortho and para position;

R3 is a 6-membered aryl or a 5- or 6-membered heteroaryl, preferably 6-membered aryl or heteroaryl, more preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe. In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (I), wherein Al is N substituted with Ri;

A2 is N;

A3 is C substituted with R% wherein R2 is connected to A3 either via a bond or via a -CH2- group;

X is OH;

LI is CH= connected to Z;

Z is imidazolidine-2, 4-dione, wherein R3 is connected to Z via a -CH2- group at the 3 position of the imidazolidine-2, 4-dione;

Rl is a 6-membered aryl or heteroaryl, preferably 6-membered aryl, optionally substituted with one, two or three, preferably one polar substituent(s) that are independently from each other selected from the group consisting of -NO2, -CN, -OH, COOH, NH-SO2-alkyl (particularly -NH-SO2-(Ci-C,)alkyl). NH-CO-alkyl (particularly -NH-CO-(Ci-Ce)alkyl), -CONH₂, and -CONH-alkyl (particularly - CONH-(Ci-C₆)alkyl);

R2 is 6-membered aryl or heteroaryl, preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe are preferably in ortho and para position;

R3 is 6-membered aryl or heteroaryl, preferably 6-membered aryl, optionally substituted with one, two or three, preferably one lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe.

In a further embodiment of the first or second aspect of the invention, the inhibitor has a structure according to formula (I), wherein Al is N substituted with Rl ;

A2 is N;

A3 is C substituted with R2, wherein R2 is connected to A3 either via a bond or via a -CH₂- group;

X OH;

LI is CH= connected to Z;

Z is imidazolidine-2, 4-dione, wherein R3 is connected to Z via a -CH2- group at the N at the 3 position of the imidazolidine-2, 4-dione;

Rl is phenyl, optionally substituted with one, two, or three, preferably one polar moieties that are independently from each other selected from the group consisting of -NO2, -CN, -OH, COOH, NH- SO2-alkyl (particularly -NH-SO2-(Ci-Ce)alkyl), NH-CO-alkyl (particularly -NH-CO-(Ci-C6)alkyl), -CONH2, and -CONH-alkyl (particularly -CONH-(Ci-C6)alkyl); R2 is any phenyl or benzyl (preferably phenyl) substituted with one, two, or three (preferably one) lipophilic substituents that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe, if R2 is substituted once than the one lipophilic substituent(s) that is independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe is preferably in para position, and if R2 is substituted twice the two lipophilic substituent(s) that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe are preferably in ortho and para position;

R3 is phenyl substituted with one, two, or three (preferably one) lipophilic substituents that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (I), wherein Al is N substituted with Ri;

A2 is N;

A3 is C substituted with R2, wherein R2 is connected to A3 either via a bond or via a -CH₂- group;

X is OH;

LI is CH= connected to Z;

Z is imidazolidine-2, 4-dione, wherein R3 is connected to Z via a -CH₂- group at the N at the 3 position of the imidazolidine-2, 4-dione;

Rl is phenyl, 4 -nitrophenyl, 2,6-dichloro-4-bromo-phenyl, 4-fluorophenyl, 4-bromophenyl, 2,6- dichlorophenyl, 2 -methylphenyl, 4 -methylphenyl, 2, 3 -dimethylphenyl, or 4-methoxyphenyl;

R2 is 2,4-dichlorophenyl, 4-chlorophenyl, phenyl, benzyl, 3-pyridine, 2-methylbenzyl, 4- fluorobenzyl, 4-chlorobenzyl, 2-methoxyphenyl, or 3 -methoxyphenyl; and

R3 is 4-fluorophenyl, 2-fluorophenyl, 3-fluorophenyl, 2,4-difluorophenyl, 2-methylphenyl, 3- methylphenyl, 4 -methylphenyl, 2-chlorophenyl, 3 -chlorophenyl, 3-pyridine, 3-methoxyphenyl, 4- nitrophenyl, 3 -nitrophenyl, 4-trifluoromethyl-phenyl, or 4 -cyanophenyl.

In a further particular embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (II):

ENTRY CHANNEL

BOTTOM VIEW

FORMULA 2

(II) wherein

A5 and A8 are each independently selected from N or CH;

A6 is selected from N or CH, or when A6 takes part in the annotated carbo- or heterocycle Z, then A6 is C;

A7 is selected from N or CH, or when A7 takes part in the annotated carbo- or heterocycle Z, then A7 is C;

L2 is selected from the gronp consisting of -CH2-R4, -CF2- R4, -CH2-CH2- R4, -CH2-CH2-CH2-R4, - O-R4, -NH-R4, -N=R4;

L3 is selected from the gronp consisting of CH2-R5, -CF2- R5, -CH2-CH2- R5, -CH2-CF2-R5, -CH2- CH2-CH2-R5, -O-R5, -NH-R5, -N=R5; or

L2 and L3 together with the A8 to which they are connected form a 5- or 6-membered heterocycle snbstitnted by R4 and/or R5;

L4 is CH₂, -CF2-, CH2-CH2, CH2-CH2-CH2, 0, N, and NH, or is absent;

Z is a 5-, 6- or 7-membered carbo- or heterocycle, optionally snbstitnted with one, two, or three, preferably one substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, -OH, Me, -CF₃, Et, -OMe, -SMe, and -NO2; and can be annulated to the central core or connected via a covalent bond

R4 is 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, -CF₃, Me, Et, -OMe, and -SMe, or R4 is hydrogen, methyl, or C00H;

R5 is a 5-, 6-, 7-, 8-, 9- or 10-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe; R6 is a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) substituents selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NO2, Me, -CF3, Et, -OMe, and -SMe; or R6 is H; or when A7 takes part in the annulated carbo- or heterocycle Z then A5 and A6 are independently selected from -N or -CH and A8 is selected from -N, -CH, -CH2-N, -CH2-CH, or -NH-CH; or pharmaceutically acceptable salt thereof, wherein R4, R5, and R6 preferably have a molecular shape and stereoelectronic properties complementary to the allosteric binding pocket.

In above formula (II) the “Entry Channel”, and “Right Channel” are merely indicated to indicate the relative position that the inhibitor of the invention will occupy when bound to the binding pocket. The indicating of the position of the three channels aids the skilled person in selecting suitable substituents from the above indicated substituents that can bind to the amino acids within the respectively indicated part of the binding pocket. Thus, in a further embodiment of the first or second aspect, each one of R4 and R5 is selected in such that it binds to ammo acids in the Entry Chanel, R6 is selected in such that it binds to amino acids in the Right Channel.

In above embodiment it is preferred that:

A5 and A6 are N; and

A7 takes part in the annulated carbo- or heterocycle, preferably carbocycle Z.

In above embodiment it is preferred that:

A5 and A6 are N;

A7 takes part in the annulated carbo- or heterocycle, preferably carbocycle Z; and

A8 is -CH₂-N, -CH2-CH, or -NH-CH, preferably -NH-CH.

In above embodiment it is preferred that: A5 is N and A8 is -N or -CH.

In above embodiment it is preferred that:

A5 is N and A8 is -N or -CH; and

A6 takes part in the annulated carbo- or heterocycle, preferably carbocycle Z.

In above embodiment it is preferred that:

L2 is selected from the group consisting of -CH2-R4, -CH2-CH2- R4, -CH2-CH2-CH2-R4.

In above embodiment it is preferred that:

L2 is selected from the group consisting of -CH2-R4, -CF2- R4, -CH2-CH2-R4, -CH2-CH2-CH2-R4, - NH-R4; and

R4 is 6-membered aryl or 5-, 6- or 7-membered heteroaryl, preferably 5- or 6 -membered heteroaryl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, -CF3, Me, Et, -OMe, and -SMe, or R4 is hydrogen, methyl, or COOH. In above embodiment it is preferred that:

L3 is selected from the group consisting of -CH2-R5, -CH2-CH2- R5, -CH2-CF2-R5;

In above embodiment it is preferred that:

L3 is selected from the group consisting of -CH2-R5, -CH2-CH2- R5, -CH2-CF2-R5; and

R5 is a 5-, 6-, 7-, 8-, 9- or 10-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

L2 and L3 together with the A8 to which they are connected form a 5- or 6-membered heterocycle substituted by R4 and R5.

In above embodiment it is preferred that:

L2 and L3 together with the A8 to which they are connected form a 5- or 6-membered heterocycle substituted by R4 and R5;

R4 is hydrogen, methyl, or COOH;

R5 is a 5-, 6-, 7-membered carbo- or heterocycle, preferably phenyl or 5- or 6-membered heteroaryl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

L4 is absent.

In above embodiment it is preferred that:

R4 is hydrogen, methyl, COOH or tetrazolyl.

In above embodiment it is preferred that:

L2 is -CH2-R4, -CH2-CH2- R4, -CH₂-CH₂-CH₂-R4; and

R4 is hydrogen, methyl, COOH or tetrazolyl.

In above embodiment it is preferred that:

R5 is any 5-, 6- 7-, 8-, 9-, or 10-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, - I, -CF₃, Me, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

R5 is C5 to C7-cycloalkyl, i.e. C5-, Cg- or Cy-cycloalkyl, Cg to Cio-bicycloalkyl, i.e. Cg-, C7-, Cs-, C9- or Cw-bicycloalkyl, Cg to Cw-spiroalkyl, i.e. Cg-, C7-, Cs-, C9- or Cio-spiroalkyl, phenyl, 5 or 6 membered heteroaryl, adamantyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe; more preferably cyclopentyl, cyclohexyl, phenyl, bromo-phenyl, bicyclo[2.2.1]heptyl, spiro[3,3]heptyl, or adamantyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or adamantyl substituted with one, or two lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe In above embodiment it is preferred that:

L3 is selected from the group consisting of -CH2-R5, -CH2-CH2- R5, -CH2-CF2-R5; and

R5 is C5 to Cr-cycloalkyl, i.e. C5-, Ce- or Ch-cycloalkyl. Ce to Cio-bicycloalkyl, i.e. Ce-, C7-, Cs-, Cg- or Cw-bicycloalkyl, Ce to Cw-spiroalkyl, i.e. Ce-, C7-, Cs-, Cg- or Cio-spiroalkyl, phenyl, 5 or 6 membered heteroaryl, adamantyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe; more preferably cyclopentyl, cyclohexyl, phenyl, bromo-phenyl, bicyclo[2.2.1]heptyl, spiro[3,3]heptyl, or adamantyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF3, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or adamantyl substituted with one, or two lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe In above embodiment it is preferred that:

R6 is a 6 membered aryl or 5-, 6- or 7-membered heteroaryl, optionally substituted with one, two, or three, preferably one substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NO2, Me, -CF₃, Et, -OMe, and -SMe or R6 is H.

In above embodiment it is preferred that:

L4 is absent; and

R6 is a 5-, or 6-membered carbo- or heterocycle, preferably 6-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) substituents selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NO2, Me, -CF₃, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

Z is a 6 membered aryl, or a 5-, 6-membered heteroaryl, preferably phenyl, optionally substituted with one, two, or three, preferably one substituent(s) selected from the group consisting of -Br, -Cl, -F, - I, -OH, Me, -CF₃, Et, -OMe, -SMe, and -NO₂.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (II), wherein A5 is N; one of A6 and A7 is CH and the other one is N; or one of A6 and A7 is C and takes part in the annulated carbo- or heterocycle Z and the other one is N;

A8 is N or CH;

L2, L3, L4 are independently from each other selected from the group consisting of CH2, -CF2-, CH2-CH2, CH2-CH2-CH2, 0, N, and NH, or are absent, or L2 and L3 together with the A8 to which they are connected form a 5- or 6-membered heterocycle substituted by R4 and R5;

Z is any 5-, 6- or 7-membered carbo- or heterocycle and can be annulated to the central core or connected via a covalent bond and optionally substituted with one, two, or three (preferably one) substituents selected from the group consisting of -Br, -Cl, -F, -I, -OH, Me, -CF₃, Et, -OMe, -SMe, and -NO2; R4 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, -CF₃, Me, Et, -OMe, and -SMe, or R4 is hydrogen, methyl, or COOH;

R5 is a 5-, 6- 7-, 8-, 9-, or 10-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, - CF₃, Me, Et, -OMe, and -SMe;

R6 is a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) substituents selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NO2, Me, - CF₃, Et, -OMe, and -SMe, or R6 is H or when A7 takes part in the annulated carbo- or heterocycle Z then A5 and A6 are N and A8 is selected from -N, -CH, -CH₂-N, -CH2-CH, or -NH-CH, preferably -CH₂-N, -CH₂-CH, or -NH-CH; wherein R4, R5, and R6 preferably have a molecular shape and stereoelectronic properties complementary to the allosteric binding pocket.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (II), wherein A5 is N; one of A6 and A7 is C and takes part in the annulated carbo- or heterocycle Z and the other one is N;

A8 is N;

L2 is CH₂-CH₂ and L3 is CH₂-CH₂ or CH₂-CF₂; or L2 and L3 together with the A8 to which they are connected form a 5- or 6-membered heterocycle (preferably piperidine or a pyrrolidine) substituted by R4 and R5;

L4 is absent;

Z is a 6-membered carbo- or heterocycle annulated to the central core, wherein Z is optionally substituted with one, two, or three (preferably one) substituents selected from the group consisting of -Br, -Cl, -F, -I, -OH, Me, -CF₃, Et, -OMe, -SMe, and NO₂;

R4 is COOH or CH₂N₄;

R5 is a 5-, 6-, 7-, or 10-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, Me, - CF₃, Et, -OMe, and -SMe;

R6 is a 5 - or 6-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NO₂, Me, -CF₃, Et, - OMe, and -SMe, or R6 is H.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (II), wherein each one of A5, A7 and A8 is N;

A6 is C and takes part in the annulated carbo- or heterocycle Z;

L2 is CH₂-CH₂-R4;

L3 is CH2-CH2-R4; or L2 and L3 together with the A8 to which they are connected form a piperidine ring or a pyrrolidine ring, substituted by R4 and R5;

L4 is absent;

Z is phenyl or cyclohexyl annulated to the central core, wherein Z is optionally substituted with one, two, or three, preferably one substituent(s) selected from the group consisting of -Br, -Cl, -F, -OH, Me, -CF₃, -OMe, and -NO₂,

R4 is COOH or tetrazolyl;

R5 is phenyl, cyclopentyl or adamantyl, optionally substituted with one, two, or three, preferably one lipophilic substituents selected from the group consisting of -Br, -CF₃, Me, -CH2-CF3, and -OMe;

R6 is a 6-membered carbo- or heterocycle, preferably phenyl or cyclohexyl; more preferably phenyl, optionally substituted with one, two, or three, preferably one substituent(s) selected from the group consisting of Br, -Cl, -F, Me, -CF₃, -OMe, and -NO2

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (IV):

ENTRY CHANNEL

BOTTOM VIEW

wherein

B is a 5-, 6-, or 7-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from 0, N, or S;

R7 is a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe;

Z1 is selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NH2, Me, -CF₃, Et, -OMe, -SMe, and -NO2; or Zl is absent,

XI is 0 or S, preferably 0; A9 is 0, NH or CH₂;

A 10 is 0, NH or CH₂; and

R8 is a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe; or pharmaceutically acceptable salt thereof, wherein R7 and R8 preferably have a molecular shape and stereoelectronic properties complementary to the allosteric binding pocket.

In above formula (IV) the “Entry Channel”, “and “Right Channel” are merely indicated to indicate the relative position that the inhibitor of the invention will occupy when bound to the binding pocket. The indicating of the position of the two channels aids the skilled person in selecting suitable substituents from the above indicated substituents that can bind to the amino acids within the respectively indicated part of the binding pocket. Thus, in a further embodiment of the first or second aspect, R7 is selected in such that it binds to amino acids in the Entry Chanel, and R8 is selected in such that it binds to amino acids in the Right Channel.

In above embodiment it is preferred that:

B is a 5-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from O, N, or S, preferably comprising 3 heteroatoms selected from N, or S, more preferably 1,2,4-thiadiazaloyl. If B is 1,2,4- thiadiazaloyl it is preferred that A9 is substituted at the 5 -position and R7 at the 3-positon of the

1 ,2,4-thiadiazaloyl.

In above embodiment it is preferred that:

XI is O;

A9 is 0 or NH,

A10 is O orNH; and

B is a 5-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from O, N, or S, preferably comprising 3 heteroatoms selected from N, or S, more preferably 1,2,4-thiadiazaloyl. If B is 1,2,4- thiadiazaloyl it is preferred that A9 is substituted at the 5 -position and R7 at the 3-positon of the

1 ,2,4-thiadiazaloyl.

In above embodiment it is preferred that:

XI is 0 or S (preferably O);

A9 is NH;

A10 is NH; and

B is a 5-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from 0, N, or S, preferably comprising 3 heteroatoms selected from N, or S, more preferably 1,2,4-thiadiazaloyl. If B is 1,2,4- thiadiazaloyl it is preferred that A9 is substituted at the 5 -position and R7 at the 3-positon of the

1 ,2,4-thiadiazaloyl.

In above embodiment it is preferred that:

XI is O; A9 is 0 or NH,

A10 is O orNH;

B is a 5-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from 0, N, or S, preferably comprising 3 heteroatoms selected from N, or S, more preferably 1,2,4-thiadiazaloyl. If B is 1,2,4- thiadiazaloyl it is preferred that A9 is substituted at the 5 -position and R7 at the 3-positon of the 1,2,4-thiadiazaloyl; and

R7 is 5- or 6-membered carbo- or heterocycle, preferably, 6-membered aryl or 5 or 6-membered heteroaryl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably R7 is phenyl or 5-membered heteroaryl, preferably thiophenyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or thiophenyl substituted with one or two, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

XI is 0 or S (preferably O);

A9 is NH;

A10 is NH;

B is a 5-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from O, N, or S, preferably comprising 3 heteroatoms selected from N, or S, more preferably 1,2,4-thiadiazaloyl. If B is 1,2,4- thiadiazaloyl it is preferred that A9 is substituted at the 5 -position and R7 at the 3-positon of the 1,2,4-thiadiazaloyl; and

R7 is 5- or 6-membered carbo- or heterocycle, preferably, 6-membered aryl or 5 or 6-membered heteroaryl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably R7 is phenyl or 5-membered heteroaryl, preferably thiophenyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or thiophenyl substituted with one or two, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

R7 is 5- or 6-membered carbo- or heterocycle, preferably, 6-membered aryl or 5 or 6-membered heteroaryl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably R7 is phenyl or 5 -membered heteroaryl, preferably thiophenyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or thiophenyl substituted with one or two, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

B is a 5-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from 0, N, or S, preferably comprising 3 heteroatoms selected from N, or S, more preferably 1,2,4-thiadiazaloyl. If B is 1,2,4- thiadiazaloyl it is preferred that A9 is substituted at the 5 -position and R7 at the 3-positon of the 1,2,4-thiadiazaloyl; and

R7 is phenyl or 5-membered heteroaryl, preferably thiophenyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or thiophenyl substituted with one or two, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (IV), wherein B is a 5-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from 0, N, or S.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (IV), wherein

XI is O;

A9 is 0 or NH; and

A10 is O orNH.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (IV), wherein

XI is 0 or S, preferably 0;

A9 is NH; and

A10 is NH.

In a further particular embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (III):

ENTRY CHANNEL

BOTTOM VIEW

wherein each A4 is independently from each other selected from N, NH, CH or CH2;

Z1 is selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NH2, Me, -CF3, Et, -OMe, -SMe, and -NO2; or Z1 is absent;

R7 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe;

R8 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe; or pharmaceutically acceptable salt thereof, wherein R7 and R8 preferably have a molecular shape and stereoelectronic properties complementary to the allosteric binding pocket.

In above formula (III) the “Entry Channel”, “and “Right Channel” are merely indicated to indicate the relative position that the inhibitor of the invention will occupy when bound to the binding pocket. The indicating of the position of the two channels aids the skilled person in selecting suitable substituents from the above indicated substituents that can bind to the amino acids within the respectively indicated part of the binding pocket. Thus, in a further embodiment of the first or second aspect, R7 is selected in such that it binds to amino acids in the Entry Chanel, and R8 is selected in such that it binds to amino acids in the Right Channel.

In above embodiment it is preferred that:

R7 is 5- or 6-membered carbo- or heterocycle, preferably, 6-membered aryl or 5 or 6-membered heteroaryl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably R7 is phenyl or 5-membered heteroaryl, preferably thiophenyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or thiophenyl substituted with one or two, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

A4 is N; and

R7 is 5- or 6-membered carbo- or heterocycle, preferably, 6-membered aryl or 5 or 6-membered heteroaryl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably R7 is phenyl or 5-membered heteroaryl, preferably thiophenyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or thiophenyl substituted with one or two, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

Z 1 is absent;

A4 is N; and

R7 is 5- or 6-membered carbo- or heterocycle, preferably, 6-membered aryl or 5 or 6-membered heteroaryl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably R7 is phenyl or 5-membered heteroaryl, preferably thiophenyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe, more preferably unsubstituted phenyl or thiophenyl substituted with one or two, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

R8 is cyclohexyl, piperidmyl, hexahydropyridazinyl, hexahydropynmidinyl, or piperazinyl, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In above embodiment it is preferred that:

Z 1 is absent;

A4 is N; and

R8 is cyclohexyl, piperidinyl, hexahydropyridazinyl, hexahydropyrimidinyl, or piperazinyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (III), wherein each A4 is N or CH,

Z1 is selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NH₂, Me, -CF₃, Et, -OMe, -SMe, and -NO₂; or Z1 is absent;

R7 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe; and

R8 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (III), wherein each A4 is N, Z1 is selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NH2, Me, -CF3, Et, -OMe, -SMe, and -NO2; or Z1 is absent;

R8 is cyclohexyl, piperidinyl, hexahydropyridazinyl, hexahydropyrimidinyl, or piperazinyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe; and

R7 is a 5 - or 6-membered carbo- or heterocycle (preferably 5 - or 6-membered aryl or heteroaryl group), optionally substituted with a methyl group or an ethyl group.

In a further embodiment of the first or second aspect of the invention, the helicase inhibitor has a structure according to formula (III), wherein each A4 is N, Z 1 is absent;

R8 is methylpiperidinyl, preferably I-methylpiperidinyl;

R7 is phenyl, optionally substituted with methyl or ethyl, or thiophene, optionally substituted with methyl or ethyl; preferably R7 is phenyl or methyl-substituted thiophenyl.

In a particular preferred embodiment of the first or second aspect of the invention, the helicase inhibitor is selected from the group consisting of the compounds shown in below Table 1 :

Table 1

In a third aspect, the present invention relates to a pharmaceutical composition comprising the inhibitor of a helicase as defined in any aspect of the invention and the inhibitor of a viral polymerase as defined in any aspect of the invention either seperately or in admixture and at at least one pharmaceutically acceptable excipient.

In a fourth aspect, the present invention relates to the pharmaceutical composition of the third aspect for use in medicine, preferaby for use in the prophylaxis or therapy of an infection with an RNA or DNA virus, preferably a single or double stranded RNA virus, more preferably a single stranded RNA virus.

In one embodiment of the first, second or fourth aspect of the invention, the inhibitor of a helicase and the inhibitor of a viral polymerase are administered in separate administration forms concomitantly or sequentially or in a single administration form.

In one embodiment of the first, second or fourth aspect of the invention, the viral infection is an infection with a virus of the realm Acinaviria. Duplodnaviria, Monodnaviria, Ribozyviria. Varidnaviria, or Riboviria. more preferably Riboviria.

In one embodiment of the first, second or fourth aspect of the invention, the viral infection is an infection with a virus of the kingdom Orlhornavirae. more preferably a virus of the phylum Pisuviricota, more preferably a virus of the class Pisonivlricetes, more preferably a virus of the order Nidovirales, more preferably a virus of the suborder Comidovirineae and most preferably a virus of the family Coronavir dae . In a preferred embodiment, the virus is a coronavirus including in particular SARS-CoV, MERS-CoV, SARS-CoV-2 and mutants thereof.

The present inventors have also discovered that inhibitors of helicases, in particular the helicases used in the first and second aspect of the above described invention can also be used in combination treatment with other inhibitors, preferably small molecule inhibitors, targeting a mechanism fundamental to viral replication and infection, in particular SARS/CoV replication and infection.

Thus, in a fifth aspect, the present invention is directed to an inhibitor of a helicase for use in combination with an inhibitor targeting viral replication and/or infection, in particular targeting SARS/CoV replication and/or infection in the prophylaxis or therapy of a viral infection, in particular of SARS/CoV.

Consequently, in a sixth aspect, the present invention is directed to an inhibitor targeting viral replication and/or infection, in particular targeting SARS/CoV replication and/or infection for use in combination with an inhibitor of a helicase in the prophylaxis or therapy of a viral infection, in particular of SARS/CoV.

In the context of the fifth and sixth aspect of the invention it is preferred that the inhibitors of the helicase are inhibitors of viral helicase, more preferably of a coronavirus helicase, most preferably of Nspl3 of SARS/CoV. Preferred examples of such inhibitors of helicases are those indicated in Formula (I) to (IV) above and in particular those indicated in Table 1 above.

The inhibitor targeting viral replication and/or infection is preferably an inhibitor of the activity of one or more non-structural protein of the virus, preferably an inhibitor of the activity of one or more non- structural protein of a coronavirus, more preferably of SARS/CoV other than a polymerase (combination therapies with an inhibitor of a polymerase are the subject of the first to fourth aspect of the present invention). Examples of such non-structural proteins are Nsp5 (also referred to as M^pr° or 3C-like proteinase).

Examples of inhibitors targeting viral replication and/or infection include pyridone-containing a- ketoamides, ritonavir, nirmatrelvir, i.e. (lR,2S,5S)-N-{(lS)-l-Cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}- 6, 6-dimethyl-3-[3-methyl-N-(trifhioroacetyl)-L-valyl]-3-azabicyclo[3.1.0]hexane-2 -carboxamide, or derivatives thereof as disclosed and claimed in PCT/IB2021/057281, ritonavir and nirmatrelvir (e.g. as sold under the name “Paxlovid™”), chloroquine, formoterol, chloroquine and formoterol, camostat mesylate, bromhexine hydrochloride, camostat mesylate and bromhexine hydrochloride, monoclonal antibodies binding to the Spike protein, ivermectin or ebselen.

Particularly, preferred combinations are inhibitors of helicases indicated in Formula (I) to (IV) above and in particular those indicated in Table 1 above with ritonavir, nirmatrelvir, or ritonavir and nirmatrelvir (e.g. “Paxlovid™).

In one embodiment of any aspect of the invention, the inhibitor of a helicase and the inhibitor of a viral polymerase, or the inhibitor of a helicase and the inhibitor targeting viral replication and/or infection, exhibit an additive, preferably synergistic effect when used in combination. In particular embodiments, the inhibitor of a helicase and the inhibitor of a viral polymerase; or the inhibitor of a helicase and the inhibitor targeting viral replication and/or infection; exhibit a Most Synergistic Area (MSA) that is indicative of an additive effect of the compounds, i.e. a MSA of <0 to 10, e.g. preferably a MSA of at least 2, at least 4, at least 6, or at least 8. In a particular preferred embodiment the MSA is at least 10, at least 11, at least 12, at least 13, at least 14; or at least 15.

In particualr embodiments, the MSA score is determined on the basis of TCIDso readout assays, as described below in section 6 of the “Examples” section (see Chapter entitled “TCIDso readout”). The presence (or absence) of a synergistic effect can be determined using the web application SynergyFinder 2.0 as published by lanevski et al., 2020, “SynergyFinder 2.0: visual analytics of multi-drug combination synergies ”, Nucleic Acids Research, 48(W1):W488-W493, with the correction published in “Correction to ‘SynergyFinder 2.0: visual analytics of multi-drug combination synergies ’” , 2022, Nucleic Acids Research, 50(12): 7198. The contents of lanevski et al., 2020 and of the indicated correction are herewith incorporated by reference in their entirety.

The calculation method described by lanevski et al., 2020 relies on calculating the difference of 4 parameter log-logistic curve fits. The authors describe their approach as a “4 parameter log-logistic curve fits” and “simple algebra”,

More specifically, the ZIP (zero interaction potency) score is derived from 4 parameter logistic curve fits. lanevski and co-workers find that, at zero interaction point, the formula corresponds to “probabilistic independence”, which is in this case (EQI): responce_A+B = responce_drugA + responce_drugB — responce_drugA X responce_drugB

For example, when having 2 drugs with 50% response each which do not interact, the result will be (50% + 50% - (50% x 50%)) = 75%.

A value of 75% equates to a ZIP score of 0.

To determine synergy, lanevski and co-workers calculate the deviation from this zero interaction point. This is done by taking the average difference between co-titration logistic curve fits and the zero interaction fit. In this case (EQ2):

For example, when having the same two drugs of EQI with 50% responce each but they do interact with + 5% over the expected responce_A+B in EQI (i.e. 75% + 5% = 80%), then EQ2 becomes :

S = 80% - 75% 8 = 5%

This corresponds to a ZIP score of 5.

EXAMPLES

Experiments

1. In Silica Characterization

Initially, a 12 ps molecular dynamics (MD) simulation was run on the first lobe of the SARS-CoV- 1 Nspl3 helicase (residues 236 to 440 from the published SARS-CoV-1 Nspl3 PDB: 6JYT) - which shares 100% sequence identity in this specific region with the SARS-CoV-2 ortholog. MD was initiated with implicit solvent. The simulation was run using a step size of 2 femtoseconds. The simulation was run on an NVIDIA Tesla V100-SXM2-32gb GPU. The MD started with an initial minimization step followed by 10,000 steps of equilibration. After which, energies and frames were written every 100 frames. After the MD simulation was complete, every 10^th frame was taken from the trajectory. These frames were aligned to the initial pose using and PCA was carried out. Plots of the PCA were generated using the first two principle components. 8 clusters of protein conformations were identified manually. A random point near the center of each cluster was extracted as PDB files. Flexible docking was then preformed into each of the 8 protein conformations on an Intel(R) Xeon(R) Platinum 8268 CPU @ 2.90GHz cpu. Docking was preformed using a proprietary compound library.

The average docking score from all of the protein conformations was used to rank the ligands from the library. The top 64 ligands were then selected for subsequent biochemical analysis. The in vitro data was correlated with the molecular docking into each of the protein frames. The frame with the best correlation with the in vitro FRET-based DNA unwinding assay measurements (Fig. 12) was chosen as the representative structure for use in more rigorous molecular docking for pose refinement of biologically active molecules. Surprisingly, these docking poses revealed a previously unknown allosteric binding site, that is located behind motif II of the active site in the interior of the protein. This pocket is not visible in the crystal structure and could only be identified by the applied molecular dynamics simulations. The pocket shows a tripartite structure with an entry channel, a left channel and a right channel. This pocket is composed of the following amino acids of the SARS-CoV/SARS-CoV-2 Nspl3 amino acids: Y277, T279, L280, Q281, G282, T307, C309, F373, D374, E375, 1376, S377, M378, A379, L384, N388, Y396, Y398, 1399, G400, D401, P406, P408, N423, V425, C426, R427, and M429. Of these residues, Y277, L384, N388, Y396, Y398, and V425 form the entry channel, T307, C309, F373, D374, E375, S377, M378, A379, and N423 form the left channel and T279, L280, Q281, G282, 1376, 1399, G400, D401, P406, P408, C426, R427, and M429 form the right channel.

Fig. 3 shows an alignment of the amino acid sequences of the seven known helicases of coronoaviruses. The alignment was generated using the Clustal Omega Multiple Sequence Alignment program available at EMBL-EBI (https://www.ebi.ac.uk/Tools/msa/clustalo/) using standard alignment parameters. The amino acids of SARS-CoV-2 Nspl3 that are part of the allosteric binding pocked noted above are highlighted by bold print as are the amino acids of the six other coronavirus helicases that are at the corresponding position in the respective helicase. The following Table 1 summarizes the level of conservation between the amino acids identified as forming the binding pocket of SARS-CoV-2 Nspl3 and the binding pocket of the six other coronavirus helicases.

Table 1

For the development of additional small molecule inhibitors that both fit into the binding pocket and have specific, favorable interactions, special attention has been paid to the following interactions between potential small molecules and the protein. Although the binding pocket is largely hydrophobic and thus binding will be dominated by hydrophobic interactions, the number of favorable interactions below should be maximized while maintaining physicochemical properties conducive to favorable pharmacokinetic properties.

(i) Hydrogen Bonds: Hydrogen bonding (H-bonding) is likely the most critical aspect for small molecule binding in general. H-bonds are formed between lone pairs of electrons and polar, electron poor hydrogens at distances of 1.5A to 2.5A. The backbone of every amino acid contains both an H bond donor and acceptor, and many amino acid sidechains contain H- bond donors, acceptors, or both. The right and left channels of the binding pocket are rich in both H-bond donors and acceptors. Fewer H-bond donors and acceptors are present in the entry channel, especially as the channel nears the center of the protein. This can be seen in figure 6 where black regions are hydrophobic, and thus poor in H-bond accepting and donating groups. To take advantage of this, H-bond acceptors and donators should be positioned on small molecule moieties directed into the left and right channel, as well as the entry channel outer boundary. (ii) Salt Bridges: Since several residues lining the binding pocket have charged sidechains - specifically aspartate 374 and 401, glutamate 375, and to some extent Arginine 427 - the potential to form salt bridges between charged amino acid sidechains and charged moieties of the small molecule can be exploited. Salt bridges are ideally formed at a distance of approximately 2A and can have interaction energies in the low double digit kcal/mol, but often suffer from the large desolvation penalty associated with the charged moiety of the small molecule. To take advantage of salt bridges, charged moieties may be directed toward the left and right channels.

(iii) pi-pi stacking: Interactions between pi bonded systems, especially aromatic pi bonded systems, are among the most prevalent intra- and intermolecular interactions. In proteins, several amino acids are capable of pi stacking with aromatic moieties in small molecules, these are phenylalanine, tyrosine, tryptophan, and histidine. In the case of the SARS-CoV-2 Nspl3 helicase allosteric binding pocket, one phenylalanine is present for pi stacking in the left channel, two tyrosines are present in the entry channel, and one tyrosine is shared between the entry and nght channel. These aromatic systems can be targeted for pi stacking by including complementary aromatic moieties in small molecules. Both face-to-face and edge-to-face interactions are highly favorable at distances of 3.5 - 5A.

(iv) Cation/Polar-pi: Cation-pi and polar-pi interactions occur between an aromatic pi system and a cation or electron poor polar region. These interactions, as in (iii) are capable of being exploited in the left and entry channels of the binding pocket with phenylalanine and tyrosine . To target these residues, the small molecules should contain polar regions or cations addressing the entry and left channels primarily. Furthermore, pi systems in the small molecules may interact with polar or charged amino acid sidechains, which are primarily present at the entry channel outer boundary, left, and right channels.

(v) Halogen bonding: Carbo halogens in small molecules have three critical electron interactions. The first is with the backbone carbonyl oxygen, which tend to occur at distances from 2. A to 3.5 A and become more favorable as the Van der Waals radius of the halogen increases. Additionally, carbo halogens interact with pi systems in a similar manner to the polar-pi interaction described in (iv). Finally, carbo halogens, especially fluorine, can form tight bonds with sulfur atoms, especially those in cystines. Halogens can be added in many locations on the small molecule, since there are potential binding interactions in many places in the binding pocket. There are pi systems able to be targeted by halogens in the left, right, and entry channel. There are backbone carbonyl oxygens able to be targeted primarily in the left and right channels. Cystine sulfurs are available in the left and right channel.

(vi) Van der Waals: nonspecific interactions between uncharged, nonpolar atoms of the protein and small molecule are the most abundant present as well as the weakest. They are present in all channels within the binding pocket but are the only available interactions in the center of the entry channel, as can be observed in figure 8 by the concentration of hydrophobic residues in this region. As such, in the development of new compounds, nonpolar substituents should be directed toward the center of the entry pocket.

The structure of the compounds subsequently tested in below assays were determined using this approach and then synthesized by various contract manufacturers under an obligation to confidentiality as indicated in Fig. 23.

2. Nspl3 Expression and Purification

A plasmid coding for the SARS-CoV-2 Nspl3 helicase with an N-terminal HislO-SUMO-tag was co-transformed with pGro7 (Takara Chaperone plasmid set #3340) into E. colt BL21 Gold (DE3) expression strain (Agilent Technologies 230132), plated on an LB-Agar plate supplemented with Chloramphenicol and Kanamycin and grown at 37°C overnight. A swab from the LB-Agar plate was used to inoculate the pre-culture (LB supplemented with Chloramphenicol and Kanamycin) and grown over night at 30°C while shaking. The pre-culture was used the next day to inoculate the expression culture 1:50. The expression culture was cultivated by shaking at 37°C until an optical density (600nm) of 0.5 - 0.8 was reached. The chaperone expression was then induced by the addition of 0.5 mg/ml (final concentration) L- arabinose. After additional shaking at 37°C for 1 h, the cultures were transferred to 25 °C and the expression of Nspl3 was induced by the addition of 0.5 mM IPTG (final concentration). The expression was allowed to proceed for 15h at 25°C, before the bacterial cells were harvested by centrifugation.

The cells were resuspended in 50 mM Tris pH 7.5, 500 mM NaCl, ImM MgCL, 20 mM Imidazole, 1 mM DTT supplemented with EDTA-free protease inhibitors (Roche) and lysed by sonication. The lysate was spun down for 30 min at 20 000 x g (4°C). The protein was purified by IMAC using lysis buffer as wash buffer and 50mM Tris pH 7.5, 500 mM NaCl, 1 mM MgCL. 500 mM Imidazole, ImM DTT as elution buffer. Elution fractions containing the target protein were pooled, supplemented with Img His6-SenP2 protease and dialyzed extensively against 20 mM Tris pH 7.5, 300 mM NaCl, 1 mM MgCL, ImM DTT. The dialyzed protein solution was spiked with 5 M NaCl to 500 mM final concentration. Uncleaved HislO- SUMO-Nspl3 and His6-SenP2 were removed by IMAC. The flow through containing the untagged target protein was diluted with 20mM Tris pH 7.5 to a final NaCl concentration of 50mM and loaded on a Heparin column operated in 20mM Hepes pH 7.5, 50 mM NaCl, ImM DTT, and eluted with a gradient to 50% 20 mM Hepes pH 7.5, 1 M NaCl, 1 mM DTT. The pure peak fractions were pooled, supplemented with 20% (v/v) glycerol and flash frozen in liquid nitrogen for storage at -80°C.

3. Nspl3 helicase unwinding assay

A FRET-based DNA unwinding assay was established for SARSCoV2 Nspl3 with an ammo acid sequence according to SEQ ID NO: 1. The helicase unwinding assay monitors fluorescence resonance energy transfer (FRET) to detect the separation of a fhiorophore-labeled reporter strand from a loading strand that is modified with a spectrally paired quencher dye by Nspl3. Helicase unwinding reactions were performed in 384 well plates in 10 mM HEPES pH 7.4, 10 mM NaCl, 0.005% BSA, 2.5% Glycerol, 2.5 mM MgCL, 0.01% CHAPS, 2 mM DTT and reaction mixtures contained 0.15 nM Nspl3 and 100 nM of fluorescein- and black hole quencher labeled dsDNA. The unwinding reaction was initiated by the addition of 200 |1M ATP and 1 pM of unlabeled single-stranded DNA (ssDNA/capture oligo which prevents reannealing and will permanently separate the reporter strand from the loading strand) followed by shaking the plates for 5 sec at 1450 rpm and sealing them with a foil compatible with fluorescence reading. The change in fluorescence was immediately recorded with a BMG labtech PheraStar FSX reader (excitation wavelength 485 nm, emission wavelength 520 nm). Unless stated otherwise, unwinding proceeded for 20 min. The increase in fluorescence was plotted as a function over time and the initial velocities ofNspl3- mediated unwinding were obtained by fitting the resulting kinetic trace by a linear curve fit. To profile compounds that modulate the unwinding activity of Nspl3, the enzyme and substrate were incubated for 30 min in the presence of the compound prior to initiating unwinding by ATP addition. The rate of unwinding (initial velocity) was determined as described above and compared against the rate of unwinding in the absence of the putative modulator/compound.

4. Malachite Green ATPase Assay

To confirm active compounds by an orthogonal method, a malachite green assay was established to validate the small molecules as inhibitors of the Nspl3 enzymatic ATP hydrolysis (Fig. 4). The malachite green assay allows the detection of organic phosphate that is released upon ATP hydrolysis by the helicase. The lOpL ATPase assay reactions were performed in transparent 384 well plates in 10 mM HEPES pH 7.4, 10 mM NaCl, 0.005% BSA, 2.5% Glycerol, 2.5 mM MgCh, 0.01% CHAPS, 2 mM DTT and 2.5% DMSO. The reaction mixtures contained 500pMNspl3 and 100 nM dsDNA of the same sequence as for the helicase assay. The reaction was started by the addition of 100 pM ATP followed by shaking the plates for 5 sec at 1450 rpm. The reaction was allowed to proceed for 5 minutes, before 20 pL Biomol Green (Enzo Life Sciences) was added to stop the reaction. The absorbance of the phosphomolybdate-malachite green complex was monitored at 650 nm on a Tecan Genios pro 4 minutes after stopping the reaction. Compounds inhibiting the ATPase activity of SARS-CoV-2 Nspl3 were profiled by incubating the compounds for 30 min with the enzyme substrate complex prior to starting the reaction with ATP. The inhibition was calculated by normalizing the blank-subtracted absorbance reads to untreated blank-subtracted controls.

5. SARS-CoV-2 nanoluciferase assay in human ACE-2 expressing A549 cells

The SARS-CoV-2 nanoluciferase assay using A549 cells expressing the human ACE-2 receptor was performed in the laboratory of Pei-Yong Shi at the University of Texas, Medical Branch on behalf of Eisbach. A549-ACE2 cells (12,000 cells per well) were seeded in phenol-red free medium supplemented with 2% FBS into clear 96-well plates. On the next day, 2-fold serial dilutions of compounds were added 1 h prior to infection with SARS-CoV-2 -Nine. At 48 h post-infection, luciferase signals were measured in lysed cells using Nano luciferase substrates (Promega). The relative luciferase signals were calculated by normalizing the luciferase signals of the compound-treated groups to that of the DMSO-treated groups (set as 100%). Experiments were performed at one (MOI = 0.025) with technical duplicates. 6. SARS-CoV-2 antiviral assay with patient isolate in VeroE6 cells

TCID50 readout

VeroE6 (10,000 cells per well) were seeded in DMEM medium supplemented with 10% FBS and 100 U penicillin / 0.1 mg/ml streptomycin in a clear 96 well plate. On the next day, 2-fold serial dilutions of compounds were added 1 h prior to infection with SARS-CoV-2 (primary SARS-CoV-2 isolate, Dusseldorf strain, MOI = 1). Ih after infection, cells were washed thrice with PBS and compounds were replenished. The cell culture medium from each well was collected 24 hr after infection and subjected to TCID50 determination. TCID50/mL values were determined by crystal violet staining and subsequent scoring of the amounts of wells displaying cytopathic effects. TCID50 was calculated by the Spearman- Karber algorithm.

The TCID50 readout was also used for co-treatment tests with RdRP inhibitors (Fig.18 and Fig. 19). A 2D-titration (Remdesivir and COVI-3 or Remdesivir and COVI-20) was performed on SARS-CoV-2 infected VeroE6 cells followed by TCID50 determination of infectious viral titers. To quantify the degree of synergy between the two compounds, the observed drug combination responses were compared with the expected additive drug response. SynergyFinder was used to explore and visualize the synergy landscape (lanevski et al., 2020, SynergyFinder 2.0: visual analytics of multi-drug combination synergies, Nucleic Acids Research). Most Synergistic Area (MSA) scores >10 are considered to be indicative of a synergistic effect at particular concentrations, while < 10 but > 0 are considered to be additive (as seen in figure 18). Similarily, Molnupiravir was tested alone or in combination with a fixed concentration (i.e., 25 pM) of different COVI compounds in the TCID50 based assay as described above to investigate effects of cotreatment.

CPE-based assay

VeroE6 (10,000 cells per well) were seeded in DMEM medium supplemented with 10% FBS and 100 U penicillin / 0.1 mg/ml streptomycin in a clear 96 well plate. On the next day, 2-fold serial dilutions of compounds were added 1 h prior to infection with SARS-CoV-2 (primary SARS-CoV-2 isolate, Dusseldorf strain). Cell viability was determined by SRB assay 72h post infection. Absorbance at 510 nm was determined in a Tecan plate reader. Experiments were performed at one MOI (MOI = 0.01, 2000 TCID50) with technical quadruplicates. Wells containing cells only and cells infected with virus were used as internal controls. Percentage of cytopathic effect (CPE) inhibition was defined as [(test compound - virus control)/(cell control - virus control)]* 100.

N-protein ELISA

VeroE6 (1,000 cells per well) were seeded in DMEM medium supplemented with 10% FBS and 100 U penicillin / 0. 1 mg/ml streptomycin in a clear 96 well plate. On the next day, 2-fold serial dilutions of compounds were added 1 h prior to infection with SARS-CoV-2 (primary SARS-CoV-2 isolate, Dusseldorf strain). After another 24 hours cells were fixed with 4% PFA and permeabilized with Triton and blocking was done with FCS. The primary antibody is directed against the N-protein. TMB was used as substrate. The reaction was stopped after 15 minutes by addition of HC1 and then measured at 450 nm in the ELISA reader. The measurements were normalized to cells treated only with live virus and DMSO.

7. hCoV-229e-Rluc antiviral assay

Huh7 cells (100,000 cells per well) were seeded in DMEM medium supplemented with 10% FBS and 100 U penicillin / 0.1 mg/ml streptomycin into white 96-well plates. On the next day, 2-fold serial dilutions of compounds were added 1 h prior to infection with hCoV-229e-Rluc. At 24 h post-infection, luciferase signals were measured in lysed cells using Coelenterazine as bioluminescent substrate and a luminometer for readout. The relative luciferase signals were calculated by normalizing the luciferase signals of the compound-treated groups to that of the DMSO-treated groups (set as 100%). Experiments were performed at an MOI = 0.01 with technical duplicates.

8. Synthesis of chemical compounds

The synthesis of compounds of general formula (I) can be carried out according to the general synthesis scheme shown in Fig. 20. The compound prepared in Fig. 20 is not shown in the list of compounds depicted in Fig. 14 but rather reflects a basic compound scaffold in which the phenyl groups are not substituted (while several compounds shown in Fig. 14 carry substituents at the phenyl groups).

For example, the synthesis of COVI-06 consists of first an N-alkylation of hydantoin with 3- fluorobenzyl bromide in DMF and NaH as a base at 0 °C and warming up to room temperature. In step 2, the product of step 1, 3-(3-fluorobenzyl)-2,4-imidazolidinedione, undergoes a condensation reaction with DMF under reflux conditions for 6 h to form (5Z)-5-[(dimethylamino)methylidene]-3-[(3- methylphenyl)methyl]imidazolidine-2, 4-dione. Step 3 consists of an aldol reaction of l-(4- chlorophenyl)ethan-l-one and dimethyl carbonate under reflux conditions for 16 hours, forming ethyl 3- (4-chlorophenyl)-3-oxopropanoate. Next, ethyl 3-(4-chlorophenyl)-3-oxopropanoate and (4- nitrophenyl)hydrazine hydrochloride form pyrazole 3 by refluxing the reaction mixture in ethanol for 16 hours. The product of this step 4 is 3-(4-chlorophenyl)-l-(4-nitrophenyl)-lH-pyrazol-5-ol, which is subsequently reacted with (5Z)-5-[(dimethylamino)methylidene]-3-[(3- methylphenyl)methyl]imidazolidine-2, 4-dione, the product from step 2 under reflux conditions for 4 hours in the presence of acetic acid to form COVI-06.

The synthesis of CO VI-20 consists first of a conversion of (3-methoxyphenyl)methanol to form 1- (bromomethyl) -3 -methoxybenzene. As expected, the subsequent steps mirror those for the synthesis of COVI-06. Step 2 is an N-alkylation reaction between l-(bromomethyl)-3-methoxybenzene and hydantoin with DMF and NaH from 0 °C to room temperature resulting in the formation of 2-hydroxy-3-[(3- methoxyphenyl)methyl]imidazolidin-4-one. In step 3, 2-hydroxy-3-[(3- methoxyphenyl)methyl]imidazolidin-4-one undergoes a condensation reaction with DMF under reflux conditions for 6 hours to form (5Z)-5-[(dimethylamino)methylidene]-2-hydroxy-3-[(3- methoxyphenyl)methyl]imidazolidin-4-one. Step 4 consists of an aldol reaction of l-(4- chlorophenyl)ethan-l-one and dimethyl carbonate under reflux conditions for 16 hours, producing ethyl 3- (4-chlorophenyl)-3-oxopropanoate. Next, in step 5, ethyl 3-(4-chlorophenyl)-3-oxopropanoate and (4- nitrophenyl)hydrazine hydrochloride are combined in a pyrazole formation reaction in ethanol under reflux conditions for 16 hours. The product of this step 4 is 3-(4-chlorophenyl)-l-(4-nitrophenyl)-lH-pyrazol-5- ol, which is subsequently reacted with (5Z)-5-[(dimethylamino)methylidene]-2-hydroxy-3-[(3- methoxyphenyl)methyl]imidazolidin-4-one in the presence of acetic acid under reflux conditions for 4 hours to form COVI-20.

Likewise, the synthesis of compounds of general formula (II) can be carried out according to the general synthesis scheme shown in Fig. 21. Again, the compound prepared in Fig. 21 is not shown in the list of compounds depicted in Fig. 14 but rather reflects a basic compound scaffold in which the phenyl groups are not substituted (while several compounds shown in Fig. 14 carry substituents at the phenyl groups).

Specifically, the synthesis of C0VL3 begins with a quinolinone formation between 2- aminobenzamide and 3 -bromobenzaldehyde in step 1. In step 2, the product of step 1, 2-(3- bromophenyl)quinazolm-4-ol undergoes chlorination by phosphoryl chloride to form 2-(3-bromophenyl)- 4-chloroquinazoline. 2-(3-bromophenyl)-4-chloroqumazoline then undergoes an amination reaction in step 3 with ethyl 3-[(2-phenylethyl)amino]propanoate - which is produced via an alkylation reaction between ethyl 3-aminopropanoate and (2-bromoethyl)benzene in the presence of DMF and potassium carbonate at 120 °C for 2 hours - again in the presence of DMF and potassium carbonate at 120 °C for 8 hours in order to form ethyl 3-{[2-(3-bromophenyl)quinazolin-4-yl](2-phenylethyl)amino}propanoate in step 4. Ethyl 3- {[2-(3-bromophenyl)quinazolin-4-yl](2-phenylethyl)amino}propanoate is subsequently subjected to an ester hydrolysis reaction with sodium hydroxide and THF-H₂O from 0 °C to room temperature for 16 hours followed by reflux for 3 hours to form CO VI-3.

Similarly, COVI-72 synthesis begins with a quinolinone formation between 2-aminobenzamide and 3 -bromobenzaldehyde in step 1. In step 2, the product of step 1, 2-(3-bromophenyl)quinazolin-4-ol undergoes chlorination by phosphoryl chloride and forms 2-(3-bromophenyl)-4-chloroquinazoline. In parallel 2-(3-ethyladamantan-l-yl)acetic acid undergoes amide formation via acid chloride to form 2-(3- ethyladamantan-l-yl)acetamide, which is reduced to the corresponding amine with lithium aluminum hydride and THF for 2 hours to form 2-(3-ethyladamantan-l-yl)ethan-l-amine. Next, in step 3, 2-(3- ethyladamantan-l-yl)ethan-l -amine undergoes cyanoalkylation with prop-2-enenitrile through heating at 100 °C for 1 hour. The product of step 3, 3-{[2-(3-ethyladamantan-l-yl)ethyl]amino}propanenitrile, is employed for aminoquinolinone formation with 2-(3-bromophenyl)-4-chloroquinazoline with DIPEA as base and dioxane at 120 °C for 16 hours, yielding 3-{[2-(3-bromophenyl)quinazolin-4-yl][2-(3- ethyladamantan-l-yl)ethyl] amino (propanenitrile. Finally, in step 5 tetrazole formation, 3-{[2-(3- bromophenyl)quinazolin-4-yl][2-(3-ethyladamantan-l-yl)ethyl]amino}propanenitrile is converted to COVI-72 heating L-proline, DMF, and sodium azide at 120 °C for 24 hours. Likewise, the synthesis of compounds of general formula (III) can be carried out according to the general synthesis scheme shown in Fig. 22.

Specifically, COVI-35 can be produced in two steps. First, an aminothiazole formation is carried out using 2-bromo-l-phenylethan-l-one and thiourea in ethanol at 50 °C for 6 hours, producing 4-phenyl-l,3- thiazol-2 -amine. 4-phenyl-l,3-thiazol-2-amine then takes part in urea formation reaction with 1- methylpiperidin-4-amine, triphosgene and DCM for 2 hours to form COVI-35.

Additionally, CO VI-85 may be produced in three steps, beginning with a Pinner reaction between ethanol and 3-methylthiophene-2-carbonitrile, catalyzed by HC1 to form ethyl 3 -methylthiophene-2 - carboximidate. Similar to COVI-35, an aminothiadiazole formation follows between ethyl 3- methylthiophene-2-carboximidate and thiourea with potassium tert-butoxide, DMSO, and molecular iodine for 16 hours at room temperature. This forms 3-(3-methylthiophen-2-yl)-l,2,4-thiadiazol-5-amine, which is used in the step 3 urea formation reaction with l-methylpiperidin-4-amine, triphosgene and DCM for 2 hours to form COVL85.

All compounds that have been rationally designed as described in Example 1 were ordered from contract manufacturers Enamine (Riga, Latvia), ChemDiv (San Diego CA, USA), or Intonation Research Laboratories (Hyderabad, India) under CDA as shown in the table in Fig. 23. The inhibitors of the invention are simple molecules to synthesize and it is within the ability of the skilled person to synthesize such molecules without any inventive activity on the basis of the structural information provided herein. Accordingly, there is a large number of contract manufacturers that can produce such compounds to order once provided with the structure to be synthesized.

Claims

Claims An inhibitor of a helicase for use in combination with an inhibitor of a viral polymerase in the prophylaxis or therapy of a viral infection. An inhibitor of a viral polymerase for use in combination with an inhibitor of a helicase in the prophylaxis or therapy of a viral infection. The inhibitor of a helicase for use of claim 1 or the inhibitor of a viral polymerase for use of claim 2, wherein the viral polymerase is a DNA dependent RNA polymerase (dDRP or RNAP), RNA- dependent DNA polymerase (RdDp) or a RNA dependent RNA polymerase (RdRp), preferably RdRp. The inhibitor of a helicase for use of claim 1 or 3 or the inhibitor of a viral polymerase for use of claim 2 or 3 , wherein the viral polymerase is a RdRp, and the inhibitor of the RdRp is a nucleoside analogue or a prodrug therof which is integrated into the viral genome. The inhibitor of a helicase for use of any of claims 1, or 3 to 4 or the inhibitor of a viral polymerase for use of any of claims 2 to 4, wherein the inhibitor of a viral polymerase is a nucleoside analogue or prodrug thereof, wherein the nucleoside analogue or prodrug thereof is preferably selected from the group consisting of deoxyadenosine analogues, in particular didanosine or vidarabine; adenosine analogues, in particular galidesivir, AT-527, or remdesivir; deoxycytidine analogues, in particular cytarabine, gemcitabine, emtricitabine, lamivudine, molnupiravir, zalcitabine; guanosine and deoxyguanosine analogues, in particular abacavir, acyclovir, or entecavir; thymidine and deoxythymidme analogues, in particular stavudine, telbivudine, or zidovudine; and deoxyuridine analogues, in particular idoxundine or tnflundine. The inhibitor of a helicase for use of any of claims 1, or 3 to 5 or the inhibitor of a viral polymerase for use of any of claims 2 to 5, wherein the inhibitor of a helicase specifically binds to an allosteric binding pocket within the N-terminal lobe of the ATPase domain of the helicase. The inhibitor of a helicase for use of any of claims 1, or 3 to 6 or the inhibitor of a viral polymerase for use of any of claims 2 to 6, wherein the inhibitor of a helicase has a structure according to formula (II): ENTRY CHANNEL

BOTTOM VIEW

wherein

A5 and A8 are each independently selected from N or CH;

A6 is selected from N or CH, or when A6 takes part in the annulated carbo- or heterocycle Z, then A6 is C;

A7 is selected from N or CH, or when A7 takes part in the annulated carbo- or heterocycle Z, then A7 is C;

L2 is selected from the group consisting of -CH₂-R4, -CF₂- R4, -CH₂-CH₂- R4, -CH₂-CH₂-CH₂- R4, -O-R4, -NH-R4, -N=R4;

L3 is selected from the group consisting of CH₂-R5, -CF₂- R5, -CH₂-CH₂- R5, -CH₂-CF₂-R5, - CH₂-CH₂-CH₂-R5, -O-R5, -NH-R5, -N=R5; or

L2 and L3 together with the A8 to which they are connected form a 5- or 6-membered heterocycle substituted by R4 and/or R5;

L4 is CH₂, -CF₂- CH₂-CH₂, CH₂-CH₂-CH₂, 0, N, and NH, or is absent;

Z is a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, -OH, Me, - CF₃, Et, -OMe, -SMe, and -N0₂; and can be annulated to the central core or connected via a covalent bond

R4 is 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, - CF₃, Me, Et, -OMe, and -SMe, or R4 is hydrogen, methyl, or COOH;

R5 is a 5-, 6-, 7-, 8-, 9- or 10-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) lipophilic substituents selected from the group consisting of - Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe;

R6 is a 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) substituents selected from the group consisting of -Br, -Cl, -F, -I, -OH, -N0₂, Me, -CF₃, Et, -OMe, and -SMe; or R6 is H; or when A7 takes part in the annulated carbo- or heterocycle Z then A5 and A6 are independently selected from -N or -CH and A8 is selected from -N, -CH, -CH2-N, -CH2-CH, or -NH-CH or a pharmaceutically acceptable salt thereof. The inhibitor of a helicase for use of claim 7 or the inhibitor of a viral polymerase for use of claim

7, wherein the inhibitor of a helicase has a structure according to formula (II), and wherein

A5 is N; one of A6 and A7 is C and takes part in the annulated 5-, 6- or 7-membered carbo- or heterocycle, preferably 5- or 6 membered aryl or heteroaryl Z and the other one is N;

A8 is N;

L2 is CH₂-CH₂-R4 and L3 is CH₂-CH₂-R5 or CH₂-CF₂-R5 or L2 and L3 together with the A8 to which they are connected form a 5- or 6-membered heterocycle, preferably piperidinyl or a pyrrolidinyl substituted by R4 and R5;

L4 is absent;

Z is any 6-membered carbo- or heterocycle, preferably 6-membered aryl or heteroaryl annulated to the central core, wherein Z is optionally substituted with one, two, or three, preferably one substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, -OH, Me, -CF₃, Et, -OMe, - SMe, and NO2;

R4 is COOH or tetrazolyl;

R5 is any 5-, 6-, or 7-membered carbo- or heterocycle, optionally substituted with one, two, orthree, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe;

R6 is any 5- or 6-membered carbo- or heterocycle, optionally substituted with one, two, or three (preferably one) substituents selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NO₂, Me, -CF₃, Et, -OMe, and -SMe, or R6 is H. The inhibitor of a helicase for use of any of claims 1, or 3 to 6 or the inhibitor of a viral polymerase for use of any of claims 2 to 6, wherein the inhibitor of a helicase has a structure according to formula (I):

ENTRY CHANNEL

BOTTOM VIEW

LEFT CHANNEL RIGHT CHANNEL wherein

Al and A3 are each independently selected from N or C;

A2 is selected from N, C or 0;

X is H or OH or NH₂;

LI is selected from the group consisting of C, CH, CH₂, 0, N, and NH; or LI is not present;

Z is any 5-, 6- or 7-membered carbo- or heterocycle substituted with R3, optionally further substituted, wherein R3 is connected to Z either via a bond or via a -CH₂- group;

R1 is H or any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -N0₂, -CN, -OH, -C00H, -NH-SO₂-alkyl, NH-CO-alkyl, -C0NH₂, - CONH-alkyl, -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe;

R2 is H or any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two or three (preferably one) lipophilic substituents that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe, wherein R2 is connected to A3 either via a bond or via a -CH₂- group;

R3 is H or any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -N0₂, -CN, -OH, -C00H, -NH-SO₂-alkyl, NH-CO-alkyl, -C0NH₂, - CONH-alkyl, -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe; or a pharmaceutically acceptable salt thereof. The inhibitor of a helicase for use of claim 9 or the inhibitor of a viral polymerase for use of claim 9, wherein the inhibitor of a helicase has a structure according to formula (I), and wherein Al is N substituted with R1 ;

A2 is N;

A3 is C substituted with R2, wherein R2 is connected to A3 either via a bond or via a -CH₂- group;

X is H or OH;

LI is CH= or CH₂ connected to Z;

Z is a 5- or 6-membered heterocycle, preferably heteroaryl substituted with R3, optionally further substituted, wherein R3 is connected to Z either via a bond or via a -CH₂- group;

R1 is a 6-membered aryl or a 5- or 6-membered heteroaryl,, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -NO₂, -CN, -OH, -C00H, -NH-SO₂-alkyl, NH-CO-alkyl, -C0NH₂, - CONH-alkyl, -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe;

R2 is 6-membered aryl or a 5- or 6-membered heteroaryl,, optionally substituted with one, two or three (preferably one) lipophilic substituents that are independently from each other selected from the group consisting of -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe; and R3 is 6-membered aryl or a 5- or 6-membered heteroaryl, optionally substituted with one, two or three (preferably one) substituents that are independently from each other selected from the group consisting of -NO2, -CN, -OH, -COOH, -NH-SO2-alkyl, NH-CO-alkyl, -CONH2, - CONH-alkyl, -Br, -Cl, -F, -I, Me, -CF₃, Et, -OMe, and -SMe. The inhibitor of a helicase for use of any of claims 1, or 3 to 6 or the inhibitor of a viral polymerase for use of any of claims 2 to 6, wherein the inhibitor of a helicase has a structure according to formula (IV):

ENTRY CHANNEL

BOTTOM VIEW

wherein

B is a 5-, 6-, or 7-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from 0, N, or S, preferably a 5-membered heterocycle comprising 1, 2, or 3 heteroatoms selected from O, N, or S;

R7 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe;

Z1 is selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NH₂, Me, -CF₃, Et, -OMe, -SMe, and -NO2; or Zl is absent,

XI is O or S;

A9 is O, NH or CH₂;

A10 is 0, NH or CH2; and

R8 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe; or a pharmaceutically acceptable salt thereof. The inhibitor of a helicase for use of claim 11 or the inhibitor of a viral polymerase of claim 11, wherein the inhibitor of a helicase has a structure according to formula (III)

ENTRY CHANNEL

BOTTOM VIEW

wherein each A4 is independently from each other selected from N, NH, CH or CH₂, preferably N or CH;

Z1 is selected from the group consisting of -Br, -Cl, -F, -I, -OH, -NH₂, Me, -CF₃, Et, -OMe, -SMe, and -NO₂; orZl is absent;

R7 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe;

R8 is any 5-, 6- or 7-membered carbo- or heterocycle, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe; preferably cyclohexyl, piperidinyl, hexahydropyridazinyl, hexahydropyrimidinyl, or piperazinyl, optionally substituted with one, two, or three, preferably one lipophilic substituent(s) selected from the group consisting of -Br, -Cl, -F, -I, Me, Et, -OMe, and -SMe; or a pharmaceutically acceptable salt thereof.

13. The inhibitor of a helicase for use of any of claims 1 , or 3 to 12 or the inhibitor of a viral polymerase for use of any of claims 2 to 12, wherein the inhibitor of a helicase is selected from the group:

A pharmaceutical composition comprising the inhibitor of a helicase as defined in any of claims 1, or 3 to 13 and the inhibitor of a viral polymerase as defined in any of claims 2 to 13 either separately or in admixture and at at least one pharmaceutically acceptable excipient. The pharmaceutical composition of claim 14 for use in medicine, preferably for use in the prophylaxis or therapy of an infection with an RNA or DNA virus, preferably a single or double stranded RNA virus, more preferably a single stranded RNA virus. The inhibitor of a viral helicase for use of any of claims 1, or 3 to 13 or the inhibitor of a viral polymerase for use of any of claims 2 to 13 or the pharmaceutical composition for use of claim 15, wherein the inhibitor of a helicase and the inhibitor of a viral polymerase are administered in a separate administration forms concomitantley or sequentially or in a single administration form. The inhibitor of a viral helicase for use of any of claims 1, 3 to 13 or 16 or the inhibitor of a viral polymerase for use of any of claims 2 to 13 or 16 or the pharmaceutical composition for use of claim 15 or 16, wherein the viral infection is an infection with a virus of the realm Adnaviria. Duplodnaviria, Monodnaviria, Ribozyviria. Varidnaviria, or Riboviria, preferably of the realm Riboviria. more peferably with a virus of the kingdom Orthornavirae. more preferably a virus of the phylum Pisuviricota more preferably a virus of the class Pisoniviricetes, more preferably a virus of the order Nidovirales, more preferably a virus of the suborder Comidovirineae and most preferably a virus of the family Coronaviridae .