Conjugated tlr7 and rig-i agonists

Abstract

This invention provides covalent conjugates of TLR7 and RIG-I agonists, processes for preparing such compounds and the use of such compounds in medicine.

Description

[0001] CONJUGATED TLR7 AND RIG-1 AGONISTS

[0002] FIELD OF THE INVENTION

[0003] The present invention provides covalent conjugates of TLR7 and RIG-1 agonists, processes for their preparation and their use in therapeutic applications.

[0004] BACKGROUND OF THE INVENTION

[0005] The innate immune system plays a vital role in defending the body against infections and tumors. It comprises specialized immune cells (e.g. dendritic cells (DCs), macrophages) equipped with various pattern recognition receptors (PRRs), including Toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs), retinoic acid-inducible gene-l-like receptors (RLRs), C-type lectin receptors (CLRs), and stimulator of interferon genes (STING). Upon activation, these cells start producing inflammatory cytokines, interferons (IFNs), and co-stimulatory molecules. This engagement serves as an essential initial signal that also determines the nature, strength, and duration of the subsequent adaptive response, including whether it manifests as a cellular or humoral response (Gutjahr et al., 2016).

[0006] RIG-1, an intracellular PRR, is responsible for detecting viral RNA and is present in the cytoplasm of almost every mammalian cell (Zevini et al., 2017). Upon activation, it triggers the IRF3 and IRF7 signaling pathways, leading to the production of type I IFNs in both immune and non-immune cells, independent of immunosuppressive cytokines like IL-10 or TGF-p. Interestingly, RIG-1 is expressed in all tumor cells, which exhibit high susceptibility to RIG-l-induced apoptosis, unlike nonmalignant cells that remain unaffected by RIG-l-induced apoptosis (Besch et al., 2009). Activation of RIG-1 in tumors not only induces apoptosis but also facilitates antigen release and activates antigen-presenting cells, effectively transforming tumors into tumor vaccines (Elion et al., 2018). Accordingly, RIG-1 agonists have shown antitumor efficiency in several in vivo studies (Elion et al., 2018; Jiang et al., 2019, 2023). On the other hand, the use of small molecule activators targeting the RIG-1 signaling pathway, known as IRF3 agonists, has also proven successful in prophylactic vaccination against influenza virus (Pattabhi et al., 2016) and has demonstrated efficient induction of mucosal responses to influenza (Yong et al., 2018; Wong et al., 2021). Various patent disclosures have reported RIG-1 agonists (alone or in combinations with small molecules or antibodies) and their medical applications (W02008 / 080091, WO2012 / 154271, US2013 / 0039887, WO2015 / 172099, US2017 / 0158772, W02018 / 053508, US2019 / 0336615, WO2019 / 246450, WO2019 / 204179, WO2020 / 225779, W02021 / 067480, WO2021 / 097347, WO2022 / 251406).

[0007] TLR7 is an intracellular receptor located in endosomes, responsible for detecting single-stranded RNA. Upon activation, it initiates signaling pathways mediated by IRF7, IRF5, and NF-KB. In humans, TLR7 is predominantly expressed in plasmacytoid DCs, and its activation leads to the production of IFNa and IL-12. These cytokines prime neighboring natural killer (NK) cells, T cells, and DCs. IFN-a enhances the cytotoxic potential of NK cells, while IL-12 boosts IFN-y secretion from NK cells. Additionally, TLR7 contributes to the maturation and differentiation of DCs, resulting in the generation of DCs with improved co-stimulatory and antigen-presenting abilities (Kobold et al., 2014). Various small molecule TLR7 agonists have been identified, including imidazoquinolines, purines, 3-deazapurines, and others (Hemmi et al., 2002; Lee et al., 2003; Jones et al., 2011). Imiquimod, a prototypical imidazoquinoline, is an effective topical cream for treating genital warts, basal cell carcinoma, and actinic keratosis. Among the purine class, 2-substituted 8-hydroxyadenines have shown potent TLR7 agonistic activity (Kurimoto et al., 2004, 2010) and can be covalently conjugated with other molecules (Akinbobuyi et al., 2016). Various studies and patent disclosures have reported purine-like TLR7 agonists and their medical applications (Tran et al., 2011; Nakamura et al., 2013; Akinbobuyi et al., 2015) (W02006 / 117670; W02007 / 024707; W02008 / 004948; W02010 / 093436; W02010 / 018134; WO2011 / 134668; W02012 / 038058; W02019 / 209811; WO2019 / 035969; W02019 / 036023; WO2019 / 035971; WO2019 / 197598).

[0008] During natural infection, pathogens often stimulate multiple innate receptors simultaneously. Similarly, effective live attenuated vaccines, including yellow fever virus vaccine, engage the immune system via synergistic stimulation of several PRRs to achieve a systemic response (Tom et al., 2019). The concept of using multiple agonists for robust activation of the immune system is the future in vaccine adjuvant / immunotherapeutic design. Cross-talk between innate immune receptors permits signal amplification and can be both quantitatively and qualitatively different than the contribution of each individual pathway (Thaiss et al., 2016). Cells treated with an innate immune agonist usually become tolerant to restimulation with the same agonist. However, if cells are restimulated with a different agonist, the response may be primed (Pashenkov et al., 2019). Simultaneous activation of distinct innate immune receptors by a mixture of agonists can bypass this tolerance and permits signal amplification, thus leading to a more efficient immune response. The covalent chemical linkage of these agonists can further enhance this response (Tom et al., 2019) as evidenced by several reported dual PRR agonists including TLR2 / TLR9 (Mancini et al., 2014), TLR4 / 9 (Madan-Lala et al., 2017), TLR2 / TLR7 (Gutjahr et al., 2017), NOD2 / TLR2 (Pavot et al., 2014), NOD2 / TLR7 (Gutjahr et al., 2020; Guzelj et al., 2022) and a trimeric adjuvant composed of TLR4, 7 and 9 agonists (Tom et al., 2015), all of which elicited potent and balanced cellular and humoral responses. Conjugation also impacts their toxicity and pharmacokinetic profiles; a chimeric TLR2 / TLR7 agonist proved to be much safer than equal amounts of individual agonists (Gutjahr et al., 2017).

[0009] In view of the great therapeutic potential of conjugated innate immune agonists, and despite the work that has already been done, there is an ongoing need for new potent compounds capable of eliciting responses from the aforementioned receptors. Thus, this specification discloses novel conjugated compounds that function as both TLR7 and RIG-1 agonists, the processes for their preparation and their uses in medicine.

[0010] SUMMARY OF THE INVENTION

[0011] In accordance with the purpose of this invention, as embodied and described herein, the present application discloses novel compounds that are synthetic TLR7 agonists covalently conjugated to synthetic RIG-1 agonists. Further provided are the processes for preparation of such compounds and the uses of such compounds in medicine.

[0012] In a first aspect, the present invention provides a compound of Formula I:

[0013] Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, wherein:

[0014] • R1is H, halogen, OH, SH, CF3, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg-Cio aryl, 5-10 membered heterocyclyl, Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkyl, Ci-Cg alkoxy-Ci-Cg alkoxy, Ci-Cg alkoxy-(Ci-Cg alkyl)S-, (Ci-C6alkyl)SO2NH-, (Ci-C6alkyl)C(=O)O-, (Ci-C6alkyl)OC(=O)-, (Ci-C6alkyl)C(=O)-, (Ci-Cg alkyl)C(=O)NH-, RaRbN-, or RaRbN(C=O)-, wherein alkyl, alkoxy, cycloalkyl, aryl, and heterocyclyl may be optionally substituted;

[0015] • R2is independently for each occurrence selected from H, halogen, OH, CHF2, CF3, CH2CF2, carboxy, CN, NO2, Ci-Cg alkyl, C3-C10 cycloalkyl, Ci-Cg alkoxy, (Ci-Cg alkyl)C(=O)-, (C6-Ci0aryl)C(=O)-, (Ci-C6alkyl)S-, (Ci-C6alkyl)C(=O)O-, (Ci-C6alkyl)OC(=O)-, (Ci-C6alkyl)C(=O)NH-, (Ci-Cg alkyl)SO2NH-, RaRbN-, and RaRbN(C=O)-, wherein alkyl, alkoxy, aryl, and cycloalkyl may be optionally substituted;

[0016] • Raand Rbare independently from each other selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, C6- C10 aryl and 5-10 membered heterocyclyl or Raland Rblmay together with the nitrogen atom form a 5-6 membered heterocycle, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0017] • X1is a single bond, -O-, -S-, -NRC-, -C(=O)- or -SO2-;

[0018] • Rcis H, Ci-Cg alkyl or C3-C10 cycloalkyl;

[0019] • L is a linking group;

[0020] • n is 0, 1, 2, 3 or 4; and

[0021] • R3is a RIG-1 agonist of Formula II: Formula II wherein:

[0022] • X2is a single bond, -O-, -S-, -NRd-, -C(=O)- or -SO2-;

[0023] • Rdis H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0024] • Y is N or CRe;

[0025] • Reis H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0026] • R4is independently for each occurrence selected from H, halogen, CN, NO2, CF3, Ci-Cg alkyl, C2- C6alkenyl, C2-C6 alkynyl, C3-C10 cycloalkyl, Cg-Cio aryl, 5-10 membered heterocyclyl, -ORf, -SRf, -C(=O)Rf, -C(=O)NRgRh, -C(=O)ORf, -OC(=O)Rf, -OC(=O)NRgRh, -NRgRh, - NRfC(=O)Rf, -SORf, -SC>2Rf, -SC>2NRgRh, and -NRfSC>2Rf, wherein alkyl, alkenyl, alkynyl, cycloalkyl, aryl, and heterocyclyl may be optionally substituted;

[0027] • Rfis independently for each occurrence selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg-Cio aryl and 5-10 membered heterocyclyl, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0028] • Rgand Rhare independently from each other selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, C6- C10 aryl and 5-10 membered heterocyclyl or Rgand Rhmay together with the nitrogen atom form a 5-6 membered heterocycle, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0029] • R5is H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0030] • R6is Ci-Cg alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C10 cycloalkyl, Cg-Cio aryl, or 5-10 membered heterocyclyl, wherein alkyl, alkenyl, alkynyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted.

[0031] In further aspect, the invention provides a process and intermediates for the preparation of compounds of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof.

[0032] In a further aspect, the present invention provides a compound of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, for use in therapy.

[0033] In a further aspect, the invention provides a pharmaceutical composition comprising a therapeutically effective amount of a compound of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, and a pharmaceutically acceptable excipient or carrier.

[0034] In a further aspect, the invention provides the use of a compound of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, in treatment of conditions for which agonism of TLR7 and RIG-1 receptors is beneficial.

[0035] In a further aspect, the invention provides the use of a compound of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof in the manufacture of a medicament.

[0036] In a further aspect, the invention provides a method for treating a subject in need thereof, comprising administering to the subject a therapeutically effective amount of a compound of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, or a pharmaceutical composition of the present invention.

[0037] In a further aspect, the invention provides a vaccine comprising a compound of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof.

[0038] The present invention can be further summarized by the following items:

[0039] 1. A compound having a structure according to Formula I:

[0040] Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, wherein:

[0041] • R1is H, halogen, OH, SH, CF3, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg-Cio aryl, 5-10 membered heterocyclyl, Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkyl, Ci-Cg alkoxy-Ci-Cg alkoxy, Ci-Cg alkoxy- (Ci-C6alkyl)S-, (Ci-C6alkyl)SO2NH-, (Ci-C6alkyl)C(=O)O-, (Ci-C6alkyl)OC(=O)-, (Ci-Cg alkyl)C(=O)-, (Ci-Cg alkyl)C(=O)NH-, RaRbN-, or RaRbN(C=O)-, wherein alkyl, alkoxy, cycloalkyl, aryl, and heterocyclyl may be optionally substituted;

[0042] • R2is independently for each occurrence selected from H, halogen, OH, CHF2, CF3, CH2CF2, carboxy, CN, NO2, Ci-Cg alkyl, C3-C10 cycloalkyl, Ci-Cg alkoxy, (Ci-Cg alkyl)C(=O)-, (C6-Ci0aryl)C(=O)-, (Ci-C6alkyl)S-, (Ci-C6alkyl)C(=O)O-, (Ci-C6alkyl)OC(=O)-, (Ci-C6alkyl)C(=O)NH-, (Ci-Cg alkyl)SO2NH-, RaRbN-, and RaRbN(C=O)-, wherein alkyl, alkoxy, aryl, and cycloalkyl may be optionally substituted;

[0043] • Raand Rbare independently from each other selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg-Cio aryl and 5-10 membered heterocyclyl or Raland Rblmay together with the nitrogen atom form a 5-6 membered heterocycle, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0044] • X1is a single bond, -O-, -S-, -NRC-, -C(=O)- or -SO2-;

[0045] • Rcis H, Ci-Cg alkyl or C3-C10 cycloalkyl;

[0046] • L is a linking group;

[0047] • n is 0, 1, 2, 3 or 4; and

[0048] • R3is a RIG-1 agonist of Formula II:

[0049] Formula II wherein:

[0050] • X2is a single bond, -O-, -S-, -NRd-, -C(=O)- or -SO2-;

[0051] • Rdis H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0052] • Y1is N or CRe;

[0053] • Reis H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0054] • R4is independently for each occurrence selected from H, halogen, CN, NO2, CF3, Ci-Cg alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C10 cycloalkyl, Cg-Cio aryl, 5-10 membered heterocyclyl, -ORf, -SRf, -C(=O)Rf, -C(=O)NRgRh, -C(=O)ORf, -OC(=O)Rf, -OC(=O)NRgRh, -NRgR h, -NRfC(=O)Rf, -SORf, -SC>2Rf, -SC>2NRgRh, and -NRfSC>2Rf, wherein alkyl, alkenyl, alkynyl, cycloalkyl, aryl, and heterocyclyl may be optionally substituted;

[0055] • Rfis independently for each occurrence selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, C6- C10 aryl and 5-10 membered heterocyclyl, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0056] • Rgand Rhare independently from each other selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, C6-Cio aryl and 5-10 membered heterocyclyl or Rgand Rhmay together with the nitrogen atom form a 5-6 membered heterocycle, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0057] • R5is H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0058] • R6is Ci-Cg alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C10 cycloalkyl, Cg-Cio aryl and 5-10 membered heterocyclyl, wherein alkyl, alkenyl, alkynyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted.

[0059] 2. Compound according to item 1, wherein n is 1.

[0060] 3. Compound according to item 1 or 2, wherein R1is H, Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkoxy, (Ci-C6alkyl)NH-, Ci-C6alkoxy-(Ci-C6alkyl)NH-, (Ci-C6alkyl)S- or CF3.

[0061] 4. Compound according to any one of items 1 to 3, wherein R1is Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkoxy, or (Ci-Cg alkyl ) N H-.

[0062] 5. Compound according to any one of items 1 to 4, wherein R1is n-BuO-.

[0063] 6. Compound according to any one of items 1 to 5, wherein R2is independently for each instance selected from H, halogen and Ci-Cg alkyl.

[0064] 7. Compound according to item 6, wherein R2is H in each instance.

[0065] 8. Compound according to any one of items 1 to 7, wherein X1is -O-, -NH- or -C(=O)-.

[0066] 9. Compound according to any one of items 1 to 8, wherein L is selected from the group consisting of an amino acid, a peptide, a non-peptidic polymeric linker and a non-polymeric aliphatic linker. 10. Compound according to item 9, wherein L is a non-peptidic polymeric linker or a non-polymeric aliphatic linker.

[0067] 11. Compound according to item 10, wherein L is a polyethylene glycol chain comprising of 2 to 100 repeating ethylene glycol units.

[0068] 12. Compound according to item 11, wherein L is a polyethylene glycol chain comprising of 2, 3, 4, 5, 6, 7, 8, 9 or 10 repeating ethylene glycol units.

[0069] 13. Compound according to item 10, wherein L is a non-polymeric aliphatic linker.

[0070] 14. Compound according to any one of items 1 to 13, wherein X2is -O-, -NH- or -C(=O)-.

[0071] 15. Compound according to any one of items 1 to 14, wherein Y is N or CH.

[0072] 16. Compound according to item 15, wherein Y is N.

[0073] 17. Compound according to any one of items 1 to 16, wherein R4is H in each instance.

[0074] 18. Compound according to any one of items 1 to 17, wherein R5is H or Ci-Cg alkyl.

[0075] 19. Compound according to item 18, wherein R5is H.

[0076] 20. Compound according to any one of items 1 to 19, wherein R6is an optionally substituted Cg-Cio aryl or an optionally substituted 5-10 membered heterocyclyl.

[0077] 21. Compound according to item 20, wherein R6is an optionally substituted Cg-Cio aryl.

[0078] 22. Compound according to item 21, wherein R6is naftyl.

[0079] 23. Compound according to any one of items 1 to 22, wherein said compound is selected from the group consisting of:

[0080] 2-(2-naphthamido)-N-(2-(2-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethoxy)ethoxy)ethyl)benzo[d]thiazole-6-carboxamide,

[0081] 2-(2-naphthamido)-N-(l-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)phenyl)-l-oxo- 6,9,12-trioxa-2-azapentadecan-15-yl)benzo[d]thiazole-6-carboxamide,

[0082] 2-(2-naphthamido)-N-(6-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)hexyl)benzo[d]thiazole-6-carboxamide,

[0083] 2-(2-naphthamido)-N-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethyl)benzo[d]thiazole-6-carboxamide, and

[0084] N-(6-(4-((4-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)benzoyl)piperazin-l- yl)methyl)piperidine-l-carbonyl)benzo[d]thiazol-2-yl)-2-naphthamide.

[0085] 24. A process for preparing a compound of Formula I as defined in any one of items 1 to 23 (with the variable groups being as defined in any one of items 1 to 23) which comprises reacting a compound of Formula IX:

[0086] Formula IX wherein R1, R2, X1, and n are as defined previously, with a compound of Formula X:

[0087] Formula X, wherein R4, R5, R6, X2, Y, and L are as defined previously; or a compound of Formula XI: Formula XI wherein R1, R2, X1, L and n are as defined previously, with a compound of Formula XII:

[0088] Formula XII wherein R4, R5, R6, X2, and Y are as defined previously; and optionally thereafter carrying out one or more of the following procedures: removing any protecting groups, forming a pharmaceutically acceptable salt, converting a compound of Formula I into another compound of Formula I.

[0089] 25. Compound of any one of item 1 to 23 for use in medicine. 26. Compound of any one of item 1 to 23 for use in treatment of a condition in which agonism of TLR7 and RIG-1 receptors is beneficial, wherein the condition is selected from the group consisting of viral infections, bacterial infections, fungal infections, protozoal infections, tumors, cancers and immunological diseases

[0090] 27. A pharmaceutical composition comprising a compound according to any one of items 1 to 23 and one or more pharmaceutically acceptable excipients or carriers.

[0091] 28. A vaccine comprising a compound according to any one of items 1 to 23.

[0092] BRIEF DESCRIPTION OF FIGURES

[0093] Figure 1 demonstrates the ability of the compounds of the invention to induce cytokine production in human PBMCs. Concentration of tested compounds was 1 pM. Intermediary compounds SG43, SB71, and their unconjugated mixture were used to compare the compounds of the invention to a TLR7 agonist, RIG-1 agonist and their unconjugated mixture, respectively.

[0094] Figure 2 demonstrates the ability of the compounds of the invention to activate the cytotoxic activity of PBMCs against K562 cancer cells. Concentration of tested compounds was 1 pM. The results are expressed as a ratio against the control (medium). IL-2 (200 U / mL) was used as the positive control. Intermediary compounds SG43, SB71, and their unconjugated mixture were used to compare the compounds of the invention to a TLR7 agonist, RIG-1 agonist and their unconjugated mixture, respectively.

[0095] Figure 3 demonstrates the ability of the compounds of the invention to promote BMDC antigen presentation to CD4+and CD8+T-lymphocytes. The results are expressed as a ratio of T cells that divided during the co-culturing period. Concentration of tested compounds was 1 pM. Intermediary compounds SG43, SB71, and their unconjugated mixture were used to compare the compounds of the invention to a TLR7 agonist, RIG-1 agonist and their unconjugated mixture, respectively.

[0096] DETAILED DESCRIPTION OF THE INVENTION

[0097] Definitions

[0098] Throughout the present specification and the accompanying claims, the word "comprise" and variations such as "comprises" and "comprising" are to be interpreted inclusively. That is, these words are intended to convey the possible inclusion of other elements or integers not specifically recited, where the context allows.

[0099] "Cj-Cj alkyl" means linear or branched alkyl group comprising of i to j carbon atoms. Non-limiting examples of alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl and hexyl.

[0100] "Cj-Cj alkoxy" means a Cj-Cj alkyl group as defined above linked to an oxygen atom. Non-limiting examples of alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, pentoxy and hexoxy.

[0101] "Cj-Cj alkenyl" means a linear or branched hydrocarbon group comprising of i to j carbon atoms containing at least one carbon-carbon double bond. Asymmetric structures are intended to include all positional and geometrical isomers. Non-limiting examples of alkenyl group include vinyl, propenyl, allyl, but-2-enyl and but-3-enyl.

[0102] "Cj-Cj alkynyl" means a linear or branched hydrocarbon group comprising of i to j carbon atoms containing at least one carbon-carbon triple bond. Non-limiting examples of alkynyl group include ethynyl, prop-2-ynyl and but-2-ynyl.

[0103] "Cj-Cj aryl" means a mono-, or bicyclic aromatic carbon-based radical comprising of i to j carbon atoms. Non-limiting examples or aryl group include phenyl and naphthyl.

[0104] "Cj-Cj cycloalkyl" means a mono-, bi-, or tricyclic, non-aromatic carbon-based radical comprising of i to j carbon atoms that is fully saturated or partially unsaturated. Non-limiting examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

[0105] "i-j membered heterocycle" means a saturated, partially saturated or unsaturated cycle consisting of one or several rings, comprising of i to j atoms of which one or more ring atoms are selected from nitrogen, oxygen or sulphur wherein a ring sulphur atom may be optionally oxidised to from the S- oxide, a ring nitrogen may be optionally oxidised to from the N-oxide, a ring nitrogen may be optionally quaternized and a -CH2- group may be optionally replaced by a -C(=O)-. Non-limiting examples of heterocyclyl groups include pyrrolidinyl, pyrrolyl, furanyl, thiophenyl, piperidinyl, pyridinyl, pyranyl, morpholinyl, piperazinyl, pyrimidiyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, oxodiazolyl, benzimidazolyl, benzoxazolyl, indolyl, isoindolyl, indolinyl, benzotriazolyl and quinolinyl.

[0106] "i-j membered heterocyclyl" means a saturated, partially saturated or unsaturated cyclic radical consisting of one or several rings, comprising of i to j atoms of which one or more ring atoms are selected from nitrogen, oxygen or sulphur wherein a ring sulphur atom may be optionally oxidised to from the S-oxide, a ring nitrogen may be optionally oxidised to from the N-oxide, a ring nitrogen may be optionally quaternized and a -CH2- group may be optionally replaced by a -C(=O)-. Non-limiting examples of heterocyclyl groups include pyrrolidinyl, pyrrolyl, furanyl, thiophenyl, piperidinyl, pyridinyl, pyranyl, morpholinyl, piperazinyl, pyrimidiyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, oxodiazolyl, benzimidazolyl, benzoxazolyl, indolyl, isoindolyl, indolinyl, benzotriazolyl and quinolinyl.

[0107] At various places in the present specification various aryl, cycloalkyl, and heterocyclyl rings are described. Unless otherwise specified, these rings can be attached to the rest of the molecule at any ring member as permitted by valency. For example, the term "a pyridine ring" or "pyridinyl" may refer to a pyridin-2-yl, pyridin-3-yl, or pyridin-4-yl ring.

[0108] "Specific side chain of an amino acid" means the R group of an amino acid with a generic formula H2NCHRCOOH. This includes but is not limited to the L and D isomers of natural amino acids arginine, histidine, lysine, aspartic acid, glutamic acid, serine, threonine, asparagine, glutamine, cysteine, glycine, proline, alanine, valine, isoleucine, leucine, methionine, phenylalanine, tyrosine or tryptophan as well as unnatural amino acids such as homoserine, ornithine, citrulline, phosphoserine, phosphothreonine, phosphotyrosine, isovaline, isoserine, allothreonine or hydroxyproline.

[0109] The term "peptide" as used herein, refers to an amino acid polymer wherein each amino acid is linked to its neighbor by an amide bond -C(=O)NH-, also called peptide bond.

[0110] The term "pharmaceutically acceptable" as used herein, refers to those compounds, materials, compositions and / or dosage forms with are, within the scope of sound medical judgement, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response or other problem or complication commensurate with a reasonable benefit / risk ratio.

[0111] "Pharmaceutically acceptable salts" means a salt of a disclosed compound that does not abrogate the biological effectiveness and retains properties of free bases or free acids, which are not biologically or otherwise undesirable. Where a compound has one or more basic groups, acid addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired acid, either neat or in a suitable inert solvent. The salt can be formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like or organic acid such as acetic acid, tartaric acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, benzoic acid, cinnamic acid, methanesulfonic acid, lactic acid, maleic acid, fumaric acid, succinic acid, and the like. Where a compound has one or more acidic groups, the salt can be formed with the addition of an organic or an inorganic base. Salts derived from inorganic bases include but are not limited to sodium, potassium, lithium, ammonium, calcium, magnesium and zinc salts. Salts derived from organic bases include but are not limited to salts of primary, secondary and tertiary amines, substituted amines, cyclic amines, naturally-occurring amines and the like, such as isopropylamine, trimethylamine, diethylamine, triethylamine, ethanolamine, lysine, arginine, piperidine, piperazine, choline, betaine, caffeine, choline, and the like. 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. A preferred pharmaceutically acceptable salt is the sodium salt.

[0112] Other salts that are not deemed pharmaceutically acceptable may be useful in the preparation of compound of Formula I and are included within the scope of this invention, such as those formed with ammonia and trifluoroacetic acid.

[0113] "Pharmaceutically acceptable esters" means that compounds of Formula I may be derivatised at carboxylic or hydroxy groups to provide derivatives which are capable of conversion back to the parent compounds in vivo. Examples of such compounds include physiologically acceptable and metabolically labile ester derivatives, such as methoxymethyl esters, methylthiomethyl ester and pivaloyloxymethyl esters. Additionally, any physiologically acceptable equivalents of the compounds of Formula I, similar to the metabolically labile esters, which are capable of producing the parent compounds of Formula I in vivo, are within the scope of this invention.

[0114] The term "optionally substituted" as used herein, refers to a group that may or may not be further substituted with one or more groups (preferably 1, 2, 3 or 4 groups, more preferably 1 or 2 groups). Permissible substituents include but are not limited to OR, SR, NR2, CN, NO2, halogen, oxo, carboxyl, CF3, CH2CF3, CHF2, OCF3, OCHF2, =NR, =N, =NOR, =N-CN, -C(=O)NR2, -NRC(=O)R, -C(=O)R, - OC(=O)R, -C(=O)OR, -NRC(=O)OR, -SO2R, -SO2NR2, -NRSO2R, Ci-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, Ci-Cg alkoxy, C3-CM cycloalkyl, Cg-Cio aryl, and 5-10 membered heterocyclyl wherein each R is H, Ci-Cg alkyl, C2-Cg alkenyl, C2-Cg alkynyl, C3-CM cycloalkyl, Cg-Cw aryl, or 5-10 membered heterocyclyl and wherein each alkyl, alkenyl, alkynyl, cycloalkyl, aryl and heterocyclyl and groups containing them may be further optionally substituted, e.g., with one or more groups (preferably 1, 2, 3 or 4 groups, more preferably 1 or 2 groups) selected from OR, SR, NR2, CN, NO2, halogen, oxo, carboxyl, CF3, CH2CF3, CHF2, OCF3, OCHF2, =NR, =N, =NOR, =N-CN, -C(=O)NR2, -NRC(=O)R, -C(=O)R, -OC(=O)R, -C(=O)OR, - NRC(=O)OR, -SO2R, -SO2NR2, and -NRSO2R.

[0115] The term "administering" as used herein, refers to parenteral, intravenous, intraperitoneal, intramuscular, intertumoral, intralesional, intranasal, subcutaneous or oral administration, administration as a suppository, topical contact, intrathecal administration, or the implantation of a slow-release device, such as a mini-osmotic pump, to the subject.

[0116] The term "subject" as used herein, refers to an animal or human body.

[0117] The term "agonist" as used herein, refers to the native ligand of a receptor, to analogues thereof or other ligand that similarly "activate" the receptor, and / or to a positive modulator of the receptor.

[0118] A RIG-1 agonist is any compound that functions to activate RIG-1 receptor.

[0119] A TLR7 agonist is any compound that functions to activate TLR7 receptor.

[0120] The term "therapeutically effective amount" as used herein, refers to the quantity of a compound of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, which will elicit the desired biological response in an animal or human body.

[0121] The term "treatment" or "treating" as used herein, includes (i) preventing a pathological condition from occurring; (ii) inhibiting the pathological condition or arresting its development; (iii) relieving the pathological condition and / or diminishing symptoms associated with the pathological condition.

[0122] "Pharmaceutical composition" means one or more active ingredients, and one or more inert ingredients, as well as any product which results, directly or indirectly, from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients. Accordingly, the pharmaceutical compositions of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable excipient (pharmaceutically acceptable carrier).

[0123] "Excipient" refers to compounds administered together with the therapeutic agent, for example, buffering agents, isotonicity modifiers, preservative, stabilizers, anti-adsorption agents, or other auxiliary agents. However, in some cases, one excipient may have dual or triple functions.

[0124] It will be appreciated by those skilled in the art that certain compounds described herein contain one or more chiral centres. Accordingly, these compounds may exist in, and be isolated in, optically active and racemic forms. Some compounds may exhibit polymorphism. Polymorphs as referred herein includes both crystalline and amorphous forms. It is to be understood that this invention encompasses any racemic, optically active, polymorphic or stereoisomeric form, or mixtures thereof, of a compound of the invention, which possesses the useful properties described herein, it being known in the art how to prepare optically-active forms (for example, by resolution of the racemic form by recrystallization techniques, by synthesis from optically-active starting materials, by stereoselective synthesis, by enzymatic resolution, by biotransformation, or by chromatographic separation using a chiral stationary phase).

[0125] In addition to salt forms, the 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 the compounds of the present invention. Prodrugs include, for example, compounds of this invention wherein hydroxy, amine or carboxy groups are bonded to any group that, when administered to a subject, cleaves to form the hydroxy, amine or carboxy groups. 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 or chemical reagent. A prodrug may improve the physical properties of the parent drug and / or it may also improve overall drug efficacy, for example through the reduction of toxicity and unwanted effects of a drug by controlling its absorption, blood levels, metabolic distribution and cellular uptake.

[0126] Within the present invention it is to be understood that a compound of Formula I or a salt thereof may exhibit the phenomenon of tautomerism and that the formulae drawings within this specification can represent only one of the possible tautomeric forms. It is to be understood that the invention encompasses any tautomeric form which possesses the useful properties described herein and is not to be limited merely to any one tautomeric form utilised within the formulae drawings. The formulae drawings within this specification can represent only one of the possible tautomeric forms and it is to be understood that the specification encompasses all possible tautomeric forms of the compounds drawn not just those forms which it has been possible to show graphically herein.

[0127] In particular, a compound of Formula lAis the tautomer of a compound of Formula lB.

[0128] Generally, tautomeric structures have been represented herein in the enol form, as a matter of consistency and convenience.

[0129] It is also to be understood that certain compounds of Formula I and salts thereof can exist in solvated as well as unsolvated forms such as, for example, hydrated forms. It is to be understood that the invention encompasses all such solvated form which possess the useful properties described herein.

[0130] In the formulae drawings within this specification a bond traversing an aromatic ring between two carbon atoms means that the attached group may be located at any of the positions on the aromatic ring, made available by removal of the hydrogen atom that is implicitly there. By way of illustration, the formula represents

[0131] In another illustration, the formula represents

[0132] Conjugates of RIG-1 and TLR7 agonists

[0133] The first aspect of the present invention are conjugated compounds of Formula I:

[0134] Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, wherein:

[0135] • R1is H, halogen, OH, SH, CF3, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg-Cio aryl, 5-10 membered heterocyclyl, Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkyl, Ci-Cg alkoxy-Ci-Cg alkoxy, Ci-Cg alkoxy-(Ci-Cg alkyl)S-, (Ci-C6alkyl)SO2NH-, (Ci-C6alkyl)C(=O)O-, (Ci-C6alkyl)OC(=O)-, (Ci-C6alkyl)C(=O)-, (Ci-Cg alkyl)C(=O)NH-, RaRbN-, or RaRbN(C=O)-, wherein alkyl, alkoxy, cycloalkyl, aryl, and heterocyclyl may be optionally substituted;

[0136] • R2is independently for each occurrence selected from H, halogen, OH, CHF2, CF3, CH2CF2, carboxy, CN, NO2, Ci-Cg alkyl, C3-C10 cycloalkyl, Ci-Cg alkoxy, (Ci-Cg alkyl)C(=O)-, (C6-Ci0aryl)C(=O)-, (Ci-C6alkyl)S-, (Ci-C6alkyl)C(=O)O-, (Ci-C6alkyl)OC(=O)-, (Ci-C6alkyl)C(=O)NH-, (Ci-Cg alkyl)SO2NH-, RaRbN-, and RaRbN(C=O)-, wherein alkyl, alkoxy, aryl, and cycloalkyl may be optionally substituted;

[0137] • Raand Rbare independently from each other selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, C6- C10 aryl and 5-10 membered heterocyclyl or Raland Rblmay together with the nitrogen atom form a 5-6 membered heterocycle, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0138] • X1is a single bond, -O-, -S-, -NRC-, -C(=O)- or -SO2-;

[0139] • Rcis H, Ci-Cg alkyl or C3-C10 cycloalkyl;

[0140] • L is a linking group;

[0141] • n is 0, 1, 2, 3 or 4; and

[0142] • R3is a RIG-1 agonist of Formula II:

[0143] Formula II wherein:

[0144] • X2is a single bond, -O-, -S-, -NRd-, -C(=O)- or -SO2-; • Rdis H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0145] • Y is N or CRe;

[0146] • Reis H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0147] • R4is independently for each occurrence selected from H, halogen, CN, NO?, CF3, Ci-Cg alkyl, C?- Cg alkenyl, C?-Cg alkynyl, C3-C10 cycloalkyl, Cg-Cio aryl, 5-10 membered heterocyclyl, -ORf, -SRf, -C(=O)Rf, -C(=O)NRgRh, -C(=O)ORf, -OC(=O)Rf, -OC(=O)NRgRh, -NRgRh, - NRfC(=O)Rf, -SORf, -SO?Rf, -SO?NRgRh, and -NRfSO?Rf, wherein alkyl, alkenyl, alkynyl, cycloalkyl, aryl, and heterocyclyl may be optionally substituted;

[0148] • Rfis independently for each occurrence selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg-Cio aryl and 5-10 membered heterocyclyl, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0149] • Rgand Rhare independently from each other selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg- Cio aryl and 5-10 membered heterocyclyl or Rgand Rhmay together with the nitrogen atom form a 5-6 membered heterocycle, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;

[0150] • R5is H, Ci-Cg alkyl, or C3-C10 cycloalkyl;

[0151] • R6is Ci-Cg alkyl, C?-Cg alkenyl, C?-Cg alkynyl, C3-C10 cycloalkyl, Cg-Cio aryl and 5-10 membered heterocyclyl, wherein alkyl, alkenyl, alkynyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted.

[0152] In some embodiments, provided herein is a compound having Formula III:

[0153] Formula III or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, wherein R1, R2, R4, R5, R6, X1, X2, L and n are as defined previously.

[0154] According to certain embodiments, n is 1 or 2.

[0155] According to certain embodiments, n is 1.

[0156] According to certain embodiments, R1is hydrogen, Ci-Cg alkoxy, Ci-Cg al koxy-Ci-Cg alkoxy, (Ci-Cg alkyl)NH-, Ci-Cg alkoxy-(Ci-C6alkyl)NH-, (Ci-Cg alkyl)S- or CF3.

[0157] According to certain embodiments, R1is Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkoxy, or (Ci-Cg alkyl) N H-.

[0158] According to certain embodiments, R1is Ci-Cg alkoxy. According to certain embodiments, R1is n-butoxy.

[0159] According to certain embodiments, R1is Ci-Cg alkoxy-Ci-Cg alkoxy.

[0160] According to certain embodiments, R1is CH2O(CH2)2O-.

[0161] According to certain embodiments, R1is (Ci-Cg al kyl) N H-.

[0162] According to certain embodiments, R1is butylamino.

[0163] According to certain embodiments, R2is independently for each occurrence selected from H, halogen or Ci-Cg alkyl.

[0164] According to certain embodiments, R2is H in each instance.

[0165] According to certain embodiments, X1is -O-, -NH- or -C(=O)-.

[0166] According to certain embodiments, X1is -C(=O)-.

[0167] According to certain embodiments, X1is in para position relative to the (CH2)ngroup.

[0168] According to certain embodiments, X2is -O-, -NH- or -C(=O)-.

[0169] According to certain embodiments, X2is -C(=O)-.

[0170] According to certain embodiments, Y is N.

[0171] According to certain embodiments, Y is CRe.

[0172] According to certain embodiments, Y is CH.

[0173] According to certain embodiments, R4is H in each instance.

[0174] According to certain embodiments, R5is H or Ci-Cg alkyl.

[0175] According to certain embodiments, R5is Ci-Cg alkyl.

[0176] According to certain embodiments, R5is methyl.

[0177] According to certain embodiments, R5is H.

[0178] According to certain embodiments, R6is an optionally substituted Cg-Cio aryl or an optionally substituted 5-10 membered heterocyclyl.

[0179] According to certain embodiments, R6is an optionally substituted 5-10 membered heterocyclyl.

[0180] According to certain embodiments, R6is an optionally substituted Cg-Cio aryl.

[0181] According to certain embodiments, R6is an optionally substituted CM aryl.

[0182] According to certain embodiments, R6is naftyl.

[0183] In some preferred embodiments of Formula I:

[0184] • R1is (Ci-Cg alkyl) N-, Ci-Cg alkoxy, or Ci-Cg alkoxy-Ci-Cg alkoxy, preferably butylamino, n-butoxy, or CH2O(CH2)2O-;

[0185] • R2is H in each instance;

[0186] • n is 1;

[0187] • X1is -C(=O)-; preferably is -C(=O)- in para position relative to the (CH2)ngroup; L is a linking group;

[0188] R3is as defined herein.

[0189] In some preferred embodiments, R3is a group of Formula II wherein:

[0190] • X2is -C(=O)-;

[0191] • R4is H in each instance;

[0192] • R5is H;

[0193] • R6is H is an optionally substituted Cg-Cio aryl or an optionally substituted 5-10 membered heterocyclyl, preferably naftyl.

[0194] In some preferred embodiments, R3is a group of Formula IV:

[0195] Formula IV

[0196] In some embodiments, provided herein is a compound of Formula V:

[0197] Formula V

[0198] Wherein R1, R6, X1, X2, and L are as defined previously.

[0199] In some embodiments, provided herein is a compound of Formula VI:

[0200] Formula VI

[0201] Wherein X1, X2, and L are as defined previously.

[0202] Preferred compounds of Formula I are selected from the group of:

[0203] 2-(2-naphthamido)-N-(2-(2-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethoxy)ethoxy)ethyl)benzo[d]thiazole-6-carboxamide,

[0204] 2-(2-naphthamido)-N-(l-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)phenyl)-l-oxo-

[0205] 6,9,12-trioxa-2-azapentadecan-15-yl)benzo[d]thiazole-6-carboxamide,

[0206] 2-(2-naphthamido)-N-(6-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)hexyl)benzo[d]thiazole-6-carboxamide,

[0207] 2-(2-naphthamido)-N-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethyl)benzo[d]thiazole-6-carboxamide, and

[0208] N-(6-(4-((4-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)benzoyl)piperazin-l- yl)methyl)piperidine-l-carbonyl)benzo[d]thiazol-2-yl)-2-naphthamide.

[0209] Linking Group

[0210] In certain embodiments of the invention, L is a linking group that functions to covalently connect a TLR7 agonist of Formula VII: to a RIG-1 agonist of Formula II:

[0211] Formula II wherein R1, R2, R4, R5, R6, X1, X2, Y, and n are as defined previously.

[0212] The specific composition of the linking group L is not critical provided the resulting conjugate retains the useful biological properties described herein. Linker type and length can be readily optimized in the context of the other substituents in the conjugated compound by using the assays provided in Example 7. The selection of a linker component is based on its documented properties of biocompatibility and solubility in aqueous and organic media.

[0213] According to certain embodiments, the linker L is a non-peptidic polymeric linker. Non-limiting examples of suitable non-peptidic polymeric linkers include polyalkylene oxides (e.g. polyethylene glycol, polypropylene glycol, and the like), polyvinyl alcohol, polyvinylpyrrolidone, and the like, as well as derivative and copolymers thereof.

[0214] According to certain embodiments, the linker L comprises a polyethylene glycol (PEG) chain. According to certain embodiments, the polyethylene glycol chain comprises from 2 to 100, such as 2 to 50, repeating ethylene glycol units. According to certain embodiments, the polyethylene glycol chain comprises 2, 3, 4, 5, 6, 7 , 8, 9 or 10 repeating ethylene glycol units. According to certain embodiments, one or both terminal hydroxy groups on the polyethylene glycol chain may be substituted with groups selected from amine, thiol, azide, carboxy, hydroxyl, N-hydroxysuccinimide and maleimide.

[0215] According to certain embodiments, the linker L is non-polymeric aliphatic linker, comprising of a divalent, linear or branched, straight or cyclic, saturated or unsaturated, hydrocarbon chain, having from 2 to 100 carbon atoms, wherein the carbon atoms are optionally replaced by a group selected from -O-, -S-, -NH-, -C(=O)-, -OC(=O)-, -N(CI-C6alkyl)-, -NHC(=O)-, -N(CI-C6alkyl)C(=O)-, -S(=O)- or - S(=O)2- and wherein the chain is optionally substituted on carbon with one or more (e.g. 1, 2, 3 or 4) substituents. The non-polymeric aliphatic linkers are typically derived from an aliphatic compound having at least two functional groups, capable of reacting with functional groups on the TLR7 and RIG- I agonist moieties (e.g. carboxy, NH2, OH, and the like).

[0216] According to certain embodiments, the linker L is a divalent radical formed from an amino acid. According to certain embodiments, the linker L is a divalent radical formed from a natural amino acid and stereoisomers thereof.

[0217] According to certain embodiments, the linker L is a divalent radical formed from a peptide. According to certain embodiments, the peptide includes naturally occurring amino acids, and stereoisomers thereof. According to certain embodiments, the peptide is formed only from naturally occurring amino acids, and stereoisomers thereof. According to certain embodiments, the linker L is a polyproline linker. According to certain embodiments, the linker L is a polyglycine linker.

[0218] According to certain embodiments, the linker L is -NH-(CH2)2-O-(CH2)2-O-(CH2)2-NH-.

[0219] According to certain embodiments, the linker L is -NH-(CH2)3-O-(CH2)2-O-(CH2)2-O-(CH2)3-NH-.

[0220] According to certain embodiments, the linker L is -NH-(CH2)6-NH-.

[0221] According to certain embodiments, the linker L is -NH-(CH2)2-NH-.

[0222] According to certain embodiments, the linker L is a group of Formula VIII:

[0223] Formula VIII

[0224] Therapeutic applications

[0225] Conjugated compounds of the present invention are TLR7 and RIG-1 agonists. Thus, compounds of Formula I or pharmaceutically acceptable salts, racemates, diastereomers, enantiomers, esters or prodrugs thereof are useful in the treatment of conditions for which modulation, especially agonism, of TLR7 and / or RIG-1 is beneficial.

[0226] Immune responses generated by simultaneous activation of both TLR7 and RIG-1 lead to the production and activation of pro-inflammatory cytokines. Thus, in one aspect, conjugated compounds of the invention are useful for the treatment of viral, bacterial, fungal, and protozoal infections, tumors or cancers, and immunological diseases.

[0227] In another aspect, a compound of the invention is useful for the treatment of a viral, bacterial, fungal or protozoal infection. According to certain embodiments, a compound of the invention is useful for the treatment of a viral infection. According to certain embodiments, a compound of the invention is useful for the treatment of a bacterial infection. According to certain embodiments, a compound of the invention is useful for the treatment of a fungal infection. According to certain embodiments, a compound of the invention is useful for the treatment of a protozoal infection.

[0228] In yet another aspect, conjugated compounds of the invention are useful for the treatment of tumors or cancer including but not limited to carcinomas, sarcomas, lymphomas, leukemia, brain cancer, cancer of the head, cancer of the reproductive system, gastrointestinal cancer, liver cancer, bile duct cancer, kidney cancer, bladder cancer, bone cancer, lung cancer, thyroid cancer, heart cancer, and metastasized cancer.

[0229] In yet another aspect, conjugated compounds of the invention are useful to treat bacterial, fungal, and protozoal infections including but not limited to infections caused by bacteria of the genus Escherichia, Enterobacter, Salmonella, Staphylococcus, Klebsiella, Proteus, Pseudomonas, Streptococcus, Chlamydia, or fungal infections such as candidiasis, aspergillosis, histoplasmosis, and cryptococcal meningitis.

[0230] According to certain embodiments, a compound of the invention is useful for the treatment of an immunological disease.

[0231] In another aspect, the conjugated compounds of the invention are useful as vaccine adjuvants. Accordingly, this specification discloses a compound of Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof for use in medicine, for immune modulation for the treatment of a disease.

[0232] Compounds of the present invention can be formulated as pharmaceutical compositions and administered to a subject, such as a human patient in a variety of forms adapted to the chosen route of administration, i.e. orally or parenterally, by intravenous, intramuscular, topical or subcutaneous routes. Pharmaceutical compositions comprising a compound of Formula I, may be prepared using techniques and methods known to those skilled in the art. Some of the methods commonly used in the art are described in Remington's The Science and Practice of Pharmacy.

[0233] Accordingly, one aspect of the invention is directed to pharmaceutical compositions comprising a compound of Formula I and one or more pharmaceutically acceptable excipients. For example, the conjugated compounds of the invention can be formulated for parenteral administration, such as intravenous administration or administration into a body cavity or lumen of an organ. Formulations for injection will commonly comprise a solution of the conjugated compound of the invention dissolved in a pharmaceutically acceptable carrier. Among the acceptable vehicles and solvents that can be employed are water and Ringer's solution. In addition, sterile fixed oils can conventionally be employed as a solvent or suspending medium. For this purpose, any bland fixed oil can be employed including synthetic monoglycerides or diglycerides. In addition, fatty acids such as oleic acid can likewise be used in the preparation of injectables. These solutions are sterile and generally free of undesirable matter. These formulations can be sterilized by conventional, well known sterilization techniques. The formulations can contain pharmaceutically acceptable auxiliary substances as required to approximate physiological conditions such as pH adjusting and buffering agents, toxicity adjusting agents, e.g., sodium acetate, sodium chloride, potassium chloride, calcium chloride, sodium lactate and the like.

[0234] These compositions can also be used as vaccine adjuvants. Thus, another aspect of the present invention is a vaccine comprising the conjugated compound of the invention.

[0235] Used as vaccine adjuvants, the compounds of Formula I and pharmaceutical compositions thereof can be administered at the same time and by the same method as the antigen (viral, bacterial, parasitic antigen and the like) against which it is desired to increase the cell immunity reactions (type IV hypersensitivity) or the production of circulating or local antibodies in the immunized subject.

[0236] Compounds of the present invention may also be administered in the form of liposomes. As is known in the art, liposomes are generally derived from phospholipids or other lipid substances. Liposomes are formed by mono- or multilamellar hydrated liquid crystals that are dispersed in an aqueous medium. Any non-toxic, physiologically acceptable and metabolizable lipid capable of forming liposomes can be used. The present compositions in lipid form can contain, in addition to a compound of the present invention, stabilizers, preservatives, excipients, and the like. Typical lipids are the phospholipid and phosphatidyl choline, both natural and synthetic. Methods of forming liposomes are known in the art and are described in Prescott's Methods in Cell Biology, which is incorporated herein by reference.

[0237] Process

[0238] Another aspect of the present invention is the process for the manufacture of compounds of Formula I or a pharmaceutically acceptable salt thereof.

[0239] If not commercially available, the necessary starting materials for the procedures such as those described below may be made by procedures which are selected from standard organic chemistry techniques, techniques which are analogous to the synthesis of knows structurally similar compounds, or techniques, which are analogous to the procedures described in the examples.

[0240] It will also be appreciated that in some of the reactions mentioned herein it may be necessary / desirable to protect any sensitive groups in compounds. The instances where protection is necessary or desirable are known to those skilled in the art, as are suitable methods for such protection.

[0241] Example of a suitable protecting group for a hydroxy group is, for example, an acyl group, for example an alkanoyl group such as acetyl, an aroyl group, for example benzoyl, a silyl group such as trimethylsilyl or an arylmethyl group, for example benzyl. The deprotection conditions for the above protecting groups will necessarily vary with the choice of protecting group. Thus, for example, an acyl group such as an alkanol or an aroyl group may be removed, for example, by hydrolysis with a suitable base such as an alkali metal hydroxide, for example lithium of sodium hydroxide. Alternatively, a silyl group such as trimethylsilyl may be removed, for example, by fluoride or by aqueous acid; or an arylmethyl group such as a benzyl group may be removed, for example, by hydrogenation in the presence of catalyst such as palladium-on-carbon.

[0242] A suitable protecting group for an amino group is, for example, any acyl group, for example an alkanoyl group such as acetyl, an alkoxycarbonyl group, for example a methoxycarbonyl, ethoxycarbonyl or t-butoxycarbonyl group, an arylmethoxycarbonyl group, for example benzyloxycarbonyl, or an aroyl group, for example benzoyl. The deprotection conditions for the above protecting groups necessarily vary with the choice of protecting group. Thus, for example, an acyl group such as an alkanoyl or alkoxycarbonyl group or an aroyl group may be removed for example, by hydrolysis with a suitable base such as an alkali metal hydroxide, for example lithium or sodium hydroxide. Alternatively an acyl group such as a t-butoxycarbonyl group may be removed, for example, by treatment with a suitable acid such as hydrochloric, sulphuric, phosphoric or trifluoroacetic acid and an arylmethoxycarbonyl group such as a benzyloxycarbonyl group may be removed, for example, by hydrogenation over a catalyst such as palladium-on-carbon, or by treatment with a Lewis acid, for example boron tris (trifluoroacetate). A suitable alternative protecting group for a primary amino group is, for example, a phthalogenyl group which may be removed by treatment with an alkylamine, for example dimethylaminopropylamine or 2-hydroxyethylamine, or with hydrazine.

[0243] Example of a suitable protecting group for a carboxy group is, for example, an alkyl group, for example a methyl, ethyl or t-butyl group or an aryl group, for example a benzyl group. The deprotection conditions for the above protecting groups necessarily vary with the choice of protecting group. Thus, for example, an alky group such as a methyl or ethyl group may be removed for example, by hydrolysis with a suitable base such as an alkali metal hydroxide, for example lithium or sodium hydroxide. Alternatively, an alkyl group such as a t-butyl group may be removed, for example, by treatment with a suitable acid such as hydrochloric, sulphuric, phosphoric or trifluoroacetic acid. An aryl group such as a benzyl group may be removed, for example, by hydrogenation over a catalyst such as palladium-on-carbon.

[0244] Other suitable protecting groups well known to those skilled in the art can be found in "Protective Groups in Organic Synthesis", 3rdEd. by Greene and Wuts (John Wiley and Sons, 1999), incorporated herein by reference.

[0245] The protecting groups may be removed at any convenient stage in the synthesis using conventional techniques well known in the chemical art, or they may be removed during a later reaction step or work-up.

[0246] Thus, the present invention also provides that the compounds of the Formula I and pharmaceutically acceptable salts thereof can be prepared by a process comprising reacting a compound of Formula IX:

[0247] Formula IX wherein R1, R2, X1, and n are as defined previously, with a compound of Formula X:

[0248] Formula X, wherein R4, R5, R6, X2, Y, and L are as defined previously; or a compound of Formula XI:

[0249] Formula XI wherein R1, R2, X1, L and n are as defined previously, with a compound of Formula XII:

[0250] Formula XII wherein R4, R5, R6, X2, and Y are as defined previously; and optionally thereafter carrying out one or more of the following procedures:

[0251] • removing any protecting groups, • forming a pharmaceutically acceptable salt,

[0252] • converting a compound of Formula I into another compound of Formula I.

[0253] Provided by these processes are conjugated compounds of Formula III and pharmaceutically acceptable salts thereof: Formula III wherein R1, R2, R4, R5, R6, X1, X2, Y, L, and n are as defined previously.

[0254] Examples METHODS OF SYNTHESIS

[0255] The present invention is further exemplified, but not limited by, the following examples that illustrate the preparation of compounds of Formula I. The use of these and other examples anywhere in the specification is illustrative only, and in no way limits the scope and meaning of the invention or of any exemplified form. Likewise, the invention is not limited to any particular preferred embodiments described herein. Indeed, many modifications and variations of the invention may be apparent to those skilled in the art upon reading this specification, and can be made without departing from its spirit and scope. The invention is therefore to be limited only by the terms of the appended claims, along with the full scope of equivalents to which the claims are entitled.

[0256] Unless otherwise stated:

[0257] • evaporation was carried out by rotary evaporation in vacuo and work-up procedures were carried out after removal of residual solids after filtration;

[0258] • operations were generally carried out at ambient temperature, that is typically between 18 and 26°C and without exclusion of air unless otherwise stated, or a person skilled in the art would otherwise work under an inert atmosphere;

[0259] • flash column chromatography was used to purify compounds and was performed on Merck Silica Gel 60 unless otherwise stated;

[0260] • yields are given for illustration only and are not necessarily the maximum attainable;

[0261] • the structure of the end-products was generally confirmed by NMR and mass spectral techniques; proton NMR spectra is quoted and was determined using a Bruker Avance III 400 MHz spectrometer operating at field strength of 400 MHz. Chemical shifts are reported in part per million downfield from tetramethylsilane as an internal standard and peak multiplicities are shown thus: s, singlet; brs, broad singlet; d, doublet; t, triplet; q, quartet; m, multiplet

[0262] • mass spectra were obtained using a Q. TOF Premier mass spectrometer (Micromass, Waters, Manchester, UK) and Exactive Plus Orbitrap mass spectrometer (Thermo Fisher Scientific, Waltham, Massachusetts, USA)

[0263] • each intermediate was generally purified to the standard required for the subsequent stage and was characterized in sufficient detail to confirm that the assigned structure was correct; purity was assessed by high pressure liquid chromatography, thin layer chromatography, or NMR and identity was determined by mass spectrometry and NMR spectroscopy as appropriate.

[0264] Abbreviations

[0265] As used herein, the symbols and conventions are consistent with those used in the contemporary scientific literature. Specifically, the following abbreviations are used in the text:

[0266] BoczO for di-tert-butyl decarbonate; CDCI3 for deuterated chloroform; COMU for (l-cyano-2-ethoxy-2- oxoethylidenaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate; DCC for N,N'- dicyclohexylcarbodiimide; DCM for dichloromethane; DIPEA for N,N-diisopropylethylamine; DMAP for 4-dimethylaminopyridine; DMF for dimethylformamide; DMSO for dimethyl sulfoxide; DMSO-d6for deuterated dimethyl sulfoxide; EDC for N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride; eq for equivalent; g for gram; HATU for l-[bis(dimethylamino)methylene]-lH-l,2,3- triazolo[4,5-b]pyridinium 3-oxid hexafluorophosphate; HCI for hydrochloric acid; HOBt for

[0267] T1 hydroxybenzotriazole; K2CO3 for potassium carbonate; LPS for lipopolysaccharides; mL for milliliter; mmol for millimole; NaHCOs for sodium hydrogen carbonate; NaOH for sodium hydroxide; Na2SO4 for sodium sulphate; Na2S2C>3 for sodium thiosulfate; NH4CI for ammonium chloride; NMR for nuclear magnetic resonance; PBS for phosphate buffered saline; RPM for revolutions per minute; rt for room temperature; TEA for triethylamine; TFA for trifluoroacetic acid

[0268] EXAMPLE 1: Compound SB71

[0269] Intermediate 1

[0270] Methyl 2-(2-naphthamido)benzo[d]thiazole-6-carboxylate: To an ice-chilled stirring solution of methyl 2-aminobenzo[d]thiazole-6-carboxylate (470 mg, 2.3 mmol, 1 eq) in DMF (3mL) were added 2- naphthoic acid (428 mg, 4.5 mmol, 1.1 eq), DIPEA (1.97 mL, 11.3 mmol, 5 eq), HOBt (336 mg, 2.5 mmol, 1.1 eq), DMAP (catalytic amount) and EDC x HCI (475 mg, 2,5 mmol, 1,1 eq). The resulting mixture was stirred at rt for 20 h. The reaction mixture was diluted with ethyl acetate (40 mL), and washed with 1% citric acid (2 x 20 mL). Saturated NaHCOs solution was added and precipitate was filtered to afford the subject compound as an off-white solid (255 mg, 31%).1H NMR (400 MHz, DMSO-dg) 6 8.87 (s, 1H), 8.72 (d, 1H), 8.17 (dd, 1H), 8.14 - 8.01 (m, 4H), 7.89 (d, 1H), 7.75 - 7.63 (m, 2H), 3.90 (s, 3H).

[0271] Compound 2

[0272] SB71

[0273] 2-(2-naphthamido)benzo[d]thiazole-6-carboxylic acid: To an ice-chilled stirring suspension of Intermediate 1 (220 mg, 0.61 mmol, 1 eq) in methanol (8 mL) was added IM NaOH( 6 mL, 6 mmol, 10 eq) dropwise. The resulting mixture was stirred at rt for 72 h. After evaporating methanol in vacuo, water (15 mL) was added and the mixture was washed with ethyl acetate (3 x 20 mL). After acidifying the mixture with IM HCI solution it was extracted three time with ethyl acetate (3 x 20 mL). The combined organic phases were dried over Na2SO4and concentrated in vacuo to afford the subject compound as a yellow solid (200 mg, 95%).XH NMR (400 MHz, DMSO-d6) 6 8.82 (d, 1H), 8.50 (s, 1H), 8.27 - 8.19 (m, 1H), 8.12 - 7.92 (m, 4H), 7.73 - 7.57 (m, 3H).

[0274] EXAMPLE 2: Compound SG43

[0275] Intermediate 3

[0276] 4-((6-amino-2-chloro-9H-purin-9-yl)methyl)benzonitrile: 2-chloroadenine (1.017 g, 6 mmol, 1.0 eq), potassium carbonate (2.579 g, 18.66 mmol 3.11 eq) and 4-(bromomethyl)benzonitrile (1.625 g, 8.29 mmol 1.38 eq) were suspended in DMSO (22 mL) and stirred at rt for 20 h. The reaction mixture was poured into ethyl acetate (130 mL) and water (90 mL). After mixing thoroughly, the mixture was concentrated in vacuo. The concentrated mixture was cooled in ice and the formed precipitate was filtered, washed with cold water and dried to afford the subject compound (1.737 g, yield: 89%).XH NMR (400 MHz, DMSO-d6) 6 8.28 (s, 1H), 7.85-7.83 (m, 4H), 7.42 (d, 2H), 5.45 (s, 2H).

[0277] Intermediate 4

[0278] 4-((6-amino-2-butoxy-9H-purin-9-yl)methyl)benzoic acid: Intermediate 3 (1.737 g, 6.10 mmol, 1 eq) was suspended in dry n-butanol (60 mL). A 20% solution of sodium n-butoxide in n-butanol (33.6 mL, 61.01 mmol, 10 eq) was added and the resulting mixture was refluxed with stirring for 20 h. The reflux was paused to cool the mixture. Water (20 mL) was added and the reflux was continued for additional 20 h. The reaction mixture was extracted three times with 80 mL of water. The combined aqueous layers were acidified to pH 3 with concentrated HCI and cooled overnight. The white precipitate obtained was filtered and dried to afford the subject compound (1.605 g, yield: 77%).1H NMR (400 MHz, DMSO-d6) 6 12.69 (br s, 1H), 8.07 (s, 1H), 7.91 (d, 2H), 7.39 (d, 2H), 7.25 (s, 2H), 5.35 (s, 2H), 4.20-4.18 (m, 2H), 1.64-1.61 (m, 2H), 1.39-1.35 (m, 2H), 0.90 (t, 3H).

[0279] Intermediate 5

[0280] 4-((6-amino-8-bromo-2-butoxy-9H-purin-9-yl)methyl)benzoic acid: Intermediate 4 (1.605 g, 4.701 mmol, 1 eq) was suspended in acetic acid (60 mL). Sodium acetate (1.928 g, 23.51 mmol, 5 eq) and bromine (1.22 mL, 23.74 mmol, 5.05 eq) were added and the resulting mixture was stirred at rt for 2 h. Aqueous NajSjOs was added to the reaction mixture. The precipitate obtained was filtered and washed with cold water and diethyl ether to afford the subject compounds as a yellow powder (1.976 g, yield 100%).^ NMR (400 MHz, DMSO-d6) 6 7.92 (d, 2H), 7.44 (brs, 2H), 7.30 (d, 2H), 5.33 (s, 2H), 4.19 (t, 2H), 1.66-1.59 (m, 2H), 1.40-1.35 (m, 2H), 0.91 (t, 3H).

[0281] Compound 6

[0282] SG43

[0283] 4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)benzoic acid: To Intermediate 5 (1.976 g, 4.701 mmol) in methanol (35 mL) was added 10 M aqueous NaOH (35 mL). The mixture was refluxed with stirring for 24 h. The solution was cooled to room temperature and acidified with 6 M HCI solution. After concentrating the mixture in vacuo, the off-white precipitate obtained was filtered and washed with water and diethyl ether to afford the subject compound (1.523 g, yield 91%).1H NMR (400 MHz, DMSO-d6) 6 10.25 (s, 1H), 7.89 (d, 2H), 7.38 (d, 2H), 6.63 (brs, 2H), 4.93 (s, 2H), 4.13 (t, 2H), 1.62-1.58 (m, 2H), 1.38-1.33 (m, 2H), 0.89 (t, 3H).

[0284] EXAMPLE 3: Compound SB77

[0285] Intermediate 7 tert-Butyl (2-(2-(2-aminoethoxy)ethoxy)ethyl)carbamate: A solution of BocjO (4.365 g, 20 mmol, 1 eq) in DCM (40 mL) was added dropwise to a stirring solution of l,2-Bis(2-aminoethoxy)ethane (14.821 g, 100 mmol, 5 eq) in DCM (100 mL) at 0 °C. The resulting mixture was stirred at rt for 20 h. Subsequently, the solution was washed with water (3 x 100 mL) and brine (100 mL), dried over anhydrous NajSCUand concentrated in vacuo to afford the subject compound as a colourless oil (4.370 g, yield: 88%).TH NMR (400 MHz, DMSO-d6) 6 6.72 (brs, 1H), 3.53 - 3.44 (m, 4H), 3.41 - 3.30 (m, 4H), 3.05 (q, 2H), 2.64 (t, 2H), 1.36 (s, 9H).

[0286] Intermediate 8 tert-Butyl (2-(2-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethoxy)ethoxy)ethyl)carbamate: Compound 6 (500 mg, 1.399 mmol, 1 eq) was dissolved in DMSO (20mL). Intermediate 7 (1.157 g, 4.659 mmol, 3.33 eq) and DIPEA (1.299 mL, 7.457 mmol, 5.33 eq) were dissolved in DCM (ImL) and added to the stirring solution of Compound 6 in DMSO. After cooling the reaction mixture in ice, COMU (1.594 g, 3.722 mmol, 2.66 eq) was added and the mixture was stirred at rt for 20h. Ethyl acetate (100 mL) and IM NaHCO3solution (75 mL) were added. After concentrating the mixture in vacuo, the mixture was cooled in ice for one hour. The precipitate was filtered and washed with water and diethyl ether to afford the subject compound, which was used for the next step without any further purification.

[0287] Intermediate 9

[0288] 4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)-N-(2-(2-(2- aminoethoxy)ethoxy)ethyl)benzamide: Intermediate 8 (491 mg, 0,84 mmol) was added to an ice- chilled stirred mixture of TFA and DCM (1 / 5, 12 mL), and the mixture was allowed to warm to room temperature. After 3 h, the solvent was evaporated in vacuo. The residue was precipitated in diethyl ether, filtered and washed with diethyl ether to afford the subject compound as a brown solid (492 mg, yield: 98%).^ NMR (400 MHz, DMSO-d6) 6 10.07 (s, 1H), 8.48 (t, 1H), 7.82 - 7.75 (m, 4H), 7.35 (d, 2H), 6.52 (brs, 2H), 4.91 (s, 2H), 4.13 (t, 2H), 3.63 - 3.49 (m, 8H), 3.46 - 3.33 (m, 2H), 3.03 - 2.88 (m, 2H), 1.67 - 1.56 (m, 2H), 1.43 - 1.30 (m, 2H), 0.90 (t, 3H).

[0289] Compound 10

[0290] SB77 2-(2-naphthamido)-N-(2-(2-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethoxy)ethoxy)ethyl)benzo[d]thiazole-6-carboxamide: To an ice-chilled stirring solution of Intermediate 9 (100 mg, 0.205 mmol, 1 eq) in DMF (1.5 mL) were added DIPEA (0.143 mL, 0.820 mmol, 4 eq), Compound 2 (79 mg, 0.226 mmol, 1.1 eq) and COMU (97 mg, 0.226 mmol, 1.1 eq). The resulting mixture was stirred at rt for 20 h. Subsequently, ethy acetate (30 mL) was added and washed with saturated NaHCOs solution (2 x 20 mL) and brine (20 mL). The organic layer was concentrated in vacuo. The crude compound was purified using preparative thin layer silica gel chromatography (4% MeOH / DCM) to afford the subject compound as a white solid (18 mg, yield: 11%).

[0291] NMR (400 MHz, DMSO-dg) 6 13.27 (s, 1H), 10.05 (s, 1H), 8.93 (s, 1H), 8.67 (d, J = 5.4 Hz, 1H), 8.60 (s, 1H), 8.56 (s, 1H), 8.23 (d, J = 8.8 Hz, 1H), 8.17 (d, J = 7.7 Hz, 2H), 8.12 (d, J = 8.1 Hz, 1H), 8.07 - 8.00 (m, 2H), 7.92 (d, J = 8.3 Hz, 1H), 7.88 - 7.82 (m, 2H), 7.79 - 7.71 (m, 2H), 7.41 (d, J = 8.3 Hz, 2H), 6.53 (s, 2H), 5.83 (s, 1H), 4.96 (s, 2H), 4.18 (t, J = 6.6 Hz, 2H), 3.60 (d, J = 15.0 Hz, 12H), 1.66 (p, J = 6.8 Hz, 2H), 1.42 (q, J = 7.4 Hz, 2H), 0.95 (t, J = 7.4 Hz, 3H).

[0292] EXAMPLE 4: Compound SB102

[0293] Intermediate 11 tert-Butyl (3-(2-(2-(3-aminopropoxy)ethoxy)ethoxy)propyl)carbamate: A solution of BocjO (2.97 g, 14 mmol, 1 eq) in DCM (35 mL) was added dropwise to a stirring solution of 3,3'-((oxybis(ethane-2,l- diyl))bis(oxy))bis(propan-l-amine) ( 15 g, 68 mmol, 5 eq) in DCM (60 mL) at 0°C. The resulting mixture was stirred at rt for 20 h. Subsequently, DCM was evaporated and saturated NaHCOs (50 mL) was added to the mixture, which was extracted two times with DCM (2 x 50 mL). Combined organic phases were washed with NaHCOs (25 mL) and brine (40 mL), dried over anhydrous NajSCU and concentrated in vacuo to afford the subject compound as a colourless oil (3.33 g, yield: 74%).z1H NMR (400 MHz, DMSO-dg) 6 6.78 (t, 1H), 3.60 - 3.30 (m, 12H), 3.04 - 2.86 (m, 2H), 2.57 (t, 2H), 1.69 - 1.47 (m, 4H), 1.37 (s, 9H).

[0294] Intermediate 12 tert-Butyl (l-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)phenyl)-l-oxo-6,9,12-trioxa-2- azapentadecan-15-yl)carbamate: Compound 6 (250 mg, 0.670 mmol, 1 eq) was dissolved in DMSO (8mL). Intermediate 11 (746 mg, 2.329 mmol, 3.33 eq), DIPEA (0.62 mL, 3.571 mmol, 5.33 eq) and COMU (763 mg, 1.782 mmol, 2.66 eq) were added to an ice-chilled mixture. The resulting mixture was stirred at rt for 20 h. Ethyl acetate (75 mL) and IM NaHCOs solution (50 mL) were added. After concentrating the mixture in vacuo, the mixture was cooled in ice for one hour. The precipitate was filtered and washed with water and diethyl ether to afford the subject compound, which was used for the next step without any further purification.

[0295] Intermediate 13

[0296] 4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)-N-(3-(2-(2-(3- aminopropoxy)ethoxy)ethoxy)propyl)benzamide: Intermediate 12 (362 mg, 0.549 mmol) was added to an ice-chilled stirred mixture of TFA and DCM (1 / 5, 20 mL), and the mixture was allowed to warm to room temperature. After 4 h, the solvent was evaporated in vacuo. The residue was coevaporated with diethyl ether to afford the subject compound as a brown solid (300 mg, yield: 98%).1H NMR (400 MHz, DMSO-dg) 6 10.07 (s, 1H), 8.41 (t, 1H), 7.77 (d, 2H), 7.35 (d, 2H), 6.56 (s, 2H), 5.31 (s, 2H), 4.91 (s, 2H), 4.14 (t, 2H), 3.55 - 3.26 (m, 12H), 3.00 - 2.77 (m, 4H), 1.76 (t, 4H), 1.69 - 1.51 (m, 2H), 1.36 (h, 2H), 1.09 (t, 2H), 0.90 (t, 3H).

[0297] Compound 14

[0298] SB102

[0299] 2-(2-naphthamido)-N-(l-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)phenyl)-l-oxo- 6,9,12-trioxa-2-azapentadecan-15-yl)benzo[d]thiazole-6-carboxamide: To an ice-chilled stirring solution of Intermediate 13 (118 mg, 0.211 mmol, 1 eq) in DMF (1.5 mL) were added Compound 2 (80 mg, 0.232 mmol, 1.1 eq), DIPEA (0.183 mL, 1.054 mmol, 5 eq) and COMU (99 mg, 0.232 mmol, 1.1 eq). The resulting mixture was stirred at rt for 20 h. Subsequently, ethy acetate (30 mL) was added and washed with saturated NaHCOs solution (2 x 20 mL) and brine (20 mL). The organic layer was concentrated in vacuo. The crude compound was purified using Isolera Biotage One Flash Chromatography (0,1% TFA, Acetonitrile, Methanol) to afford the subject compound as a bright yellow solid (17 mg, yield: 9%).TH NMR (400 MHz, DMSO-d6) 6 10.17 (s, 1H), 8.72 (s, 1H), 8.41 (t, 1H), 8.35 - 8.26 (m, 2H), 8.16 (d, 1H), 8.03 (d, 1H), 7.92 (m, 3H), 7.86 - 7.75 (m, 2H), 7.70 (dd, 1H), 7.53 (dd, 2H), 7.42 (d, 1H), 7.34 (d, 2H), 6.52 (s, 1H), 4.90 (s, 2H), 4.12 (t, 2H), 3.60 - 3.43 (m, 16H), 1.84 - 1.68 (m, 5H), 1.66 - 1.53 (m, 2H), 1.35 (q, 2H), 0.89 (t, 3H).

[0300] EXAMPLE 5: Compound SB106

[0301] Intermediate 15: tert-Butyl (6-aminohexyl)carbamate: A solution of BocjO (3.756 g, 17 mmol, 1 eq) in DCM (35 mL) was added dropwise to a stirring solution of hexane-l,6-diamine (10 g, 96 mmol, 5 eq) in DCM (65 mL) at 0°C. The resulting mixture was stirred at rt for 20 h. Subsequently, DCM was evaporated and saturated NaHCOa was added to the mixture, which was extracted two times with DCM (2 x 50 mL). Combined organic phases were washed with NaHCOa (2 x 25 mL) and brine (40 mL), dried over anhydrous NajSCU and concentrated in vacuo to afford the subject compound as a white solid (2.47 g, yield: 67%).1H NMR (400 MHz, DMSO-d6) 6 6.77 (t, 1H), 2.88 (td, 2H), 1.45 - 1.13 (m, 21H).

[0302] Intermediate 16 tert-butyl (6-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)benzamido)hexyl)carbamate: Compound 6 (250 mg, 0.670 mmol, 1 eq) was dissolved in DMSO (8mL). Intermediate 15 (500 mg, 2.329 mmol, 3.33 eq), DIPEA (0.62 mL, 3.571 mmol, 5.33 eq) and COMU (763 mg, 1.782 mmol, 2.66 eq) were added to an ice-chilled mixture. The resulting mixture was stirred at rt for 20 h. Ethyl acetate (75 mL) and IM NaHCO3solution (50 mL) were added. After concentrating the mixture in vacuo, the mixture was cooled in ice for one hour. The precipitate was filtered and washed with water and diethyl ether to afford the subject compound, which was used for the next step without any further purification.TH NMR (400 MHz, DMSO-d6) 6 9.98 (s, 1H), 8.39 (t, 1H), 7.77 (d, 2H), 7.34 (d, 2H), 6.78 (d, 1H), 6.48 (s, 2H), 4.90 (s, 2H), 4.13 (t, 2H), 3.27 - 3.05 (m, 2H), 2.98 - 2.81 (m, 2H), 1.67 - 1.17 (m, 23H), 0.90 (t, 3H).

[0303] Intermediate 17

[0304] 4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)-N-(6-aminohexyl)benzamide: Intermediate 16 (372 mg, 0.670 mmol) was added to an ice-chilled stirred mixture of TFA and DCM (1 / 5, 20 mL), and the mixture was allowed to warm to room temperature. After 4 h, the solvent was evaporated in vacuo. The residue was coevaporated with diethyl ether to afford the subject compound as a brown solid (300 mg, yield: 98%), which was used for the next step without any further purification. Compound 18

[0305] SB106

[0306] 2-(2-naphthamido)-N-(6-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)hexyl)benzo[d]thiazole-6-carboxamide: To an ice-chilled stirring solution of Intermediate 17 (100 mg, 0.219 mmol, 1 eq) in DMF (1.5 mL) were added Compound 2 (84 mg, 0.241 mmol, 1.1 eq), DIPEA (0.191 mL, 1.09 mmol, 5 eq) and COMU (103 mg, 0.241 mmol, 1.1 eq). The resulting mixture was stirred at rt for 20 h. Subsequently, ethy acetate (30 mL) was added and washed with IM HCI (2 x 20 mL), saturated NaHCOs solution (2 x 20 mL) and brine (20 mL). The organic layer was concentrated in vacuo. The crude compound was purified using preparative thin layer silica gel chromatography (3,3 % MeOH / DCM) to afford the subject compound as an off-white solid (6 mg, yield: 4%).TH NMR (400 MHz, DMSO-d6) 6 13.19 (s, 1H), 9.98 (s, 1H), 8.86 (s, 1H), 8.51 (s, 2H), 8.41 (d, 1H), 8.17 (d, 1H), 8.14 - 8.08 (m, 2H), 8.05 (d, 1H), 7.95 (d, 1H), 7.84 (d, 1H), 7.78 (d, 2H), 7.74 - 7.63 (m, 2H), 7.34 (d, 2H), 6.46 (s, 1H), 4.90 (s, 2H), 4.12 (t, 2H), 3.23 (s, 4H), 1.67 - 1.47 (m, 6H), 1.35 (q, 6H), 0.89 (t, 3H).

[0307] EXAMPLE 6: Compound SB110

[0308] Intermediate 19 tert-Butyl (2-aminoethyl)carbamate: A solution of BocjO (7.26 g, 33 mmol, 1 eq) in DCM (35 mL) was added dropwise to a stirring solution of ethylenediamine (10 g, 167 mmol, 5 eq) in DCM (60 mL) at 0°C. The resulting mixture was stirred at rt for 20 h. Subsequently, DCM was evaporated and saturated NaHCOs was added to the mixture, which was extracted three times with DCM (3 x 50 mL). Combined organic phases were washed with NaHCO3 (2 x 25 mL) and brine (40 mL), dried over anhydrous NajSCU and concentrated in vacuo to afford the subject compound as a yellow solid (2.927 g, yield: 53%).1H NMR (400 MHz, DMSO-d6) 6 6.75 (t, 1H), 2.91 (dt, 2H), 2.52 (d, 2H), 1.37 (d, 11H).

[0309] Intermediate 20 tert-Butyl (2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)benzamido)ethyl)carbamate: Compound 6 (225 mg, 0.630 mmol, 1 eq) was dissolved in DMSO (8mL). Intermediate 19 (336 mg, 2.096 mmol, 3.33 eq), DIPEA (0.58 mL, 3.358 mmol, 5.33 eq) and COMU (717 mg, 1.676 mmol, 2.66 eq) were added to an ice-chilled mixture. The resulting mixture was stirred at rt for 20 h. Ethyl acetate (75 mL) and IM NaHCOs solution (50 mL) were added. After concentrating the mixture in vacuo, the mixture was cooled in ice for one hour. The precipitate was filtered and washed with water and hexane to afford the subject compound, which was used for the next step without any further purification.1H NMR (400 MHz, DMSO-d6) 6 10.03 (s, 1H), 8.55 - 8.32 (m, 1H), 7.77 (d, 2H), 7.34 (d, 2H), 6.90 (s, 1H), 6.49 (s, 1H), 4.90 (s, 2H), 4.12 (t, 2H), 3.32 - 3.18 (m, 2H), 3.07 (d, 2H), 1.61 (p, 2H), 1.36 (s, 11 H), 0.90 (t, 3H).

[0310] Intermediate 21

[0311] 4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)-N-(2-aminoethyl)benzamide: Intermediate 20 (260 mg, 0.521 mmol) was added to an ice-chilled stirred mixture of TFA and DCM (1 / 5, 20 mL), and the mixture was allowed to warm to room temperature. After 3 h, the solvent was evaporated in vacuo. The residue was coevaporated with diethyl ether to afford the subject compound as a brown solid (205 mg, yield: 99%), which was used for the next step without any further purification

[0312] Compound 22:

[0313] SB110 2-(2-naphthamido)-N-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethyl)benzo[d]thiazole-6-carboxamide: To an ice-chilled stirring solution of Intermediate 21 (170 mg, 0.175 mmol, 1 eq) in DMF (1.5 mL) were added, Compound 2 (67 mg, 0.193 mmol, 1.1 eq), DIPEA (0.153 mL, 0.876 mmol, 5 eq) and COMU (82 mg, 0.193 mmol, 1.1 eq). The resulting mixture was stirred at rt for 20 h. Subsequently, ethy acetate (30 mL) was added and washed with IM HCI (2 x 20 mL), saturated NaHCO3 solution (2 x 20 mL) and brine (20 mL). The organic layer was concentrated in vacuo. The crude compound was purified using preparative thin layer silica gel chromatography (2,5% MeOH / DCM) to afford the subject compound as an off-white solid (15 mg, yield: 12%).TH NMR (400 MHz, DMSO-d6) 6 13.21 (s, 1H), 9.99 (s, 1H), 8.86 (s, 1H), 8.69 (s, 1H), 8.61 (s, 1H), 8.53 (s, 1H), 8.17 (d, 1H), 8.11 (d, 2H), 8.05 (d, 1H), 7.96 (q, 2H), 7.81 (d, 2H), 7.76 - 7.63 (m, 2H), 7.36 (d, 2H), 6.47 (s, 2H), 4.91 (s, 2H), 4.12 (t, 2H), 3.46 (d, 4H), 1.61 (p, 2H), 1.42 - 1.30 (m, 2H), 0.89 (t, 3H).

[0314] EXAMPLE 7: Compound SB149

[0315] Intermediate 23 tert-Butyl 4-((4-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)benzoyl)piperazin-l- yl)methyl)piperidine-l-carboxylate: Compound 6 (180 mg, 0.504 mmol, 1 eq) was dissolved in DMSO (4.5mL). tert-butyl 4-(piperazin-l-ylmethyl)piperidine-l-carboxylate (130 mg, 0.458 mmol, 1 eq), DIPEA (0.40 mL, 2.290 mmol, 5 eq) and COMU (216 mg, 0,504 mmol, 1 eq) were added to an ice-chilled mixture. The resulting mixture was stirred at rt for 20 h. Ethyl acetate (40 mL) and IM NaHCO3solution (30 mL) were added. After concentrating the mixture in vacuo, the mixture was cooled in ice for one hour. The precipitate was filtered and washed with water and hexane to afford the subject compound (200 mg, 70%). NMR (400 MHz, DMSO-d6) 6 10.10 (s, 1H), 7.33 (s, 4H), 6.51 (s, 2H), 4.89 (s, 2H), 4.15 (dt, 2H), 3.90 (d, 2H), 3.58 (s, 2H), 2.68 (d, 3H), 2.28 (s, 3H), 2.12 (d, 2H), 1.73 - 1.57 (m, 6H), 1.38 (s, 14H), 0.90 (t, 3H).

[0316] Intermediate 24

[0317] (4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)phenyl)(4-(piperidin-4-ylmethyl)piperazin- l-yl)methanone: Intermediate 23 (200 mg, 0.321 mmol) was added to an ice-chilled stirred mixture of TFA and DCM (1 / 5, 6 mL), and the mixture was allowed to warm to room temperature. After 3 h, the solvent was evaporated in vacuo. The residue was coevaporated with diethyl ether to afford the subject compound as a brown solid (165 mg, yield: 99%), which was used for the next step without any further purification

[0318] Compound 25

[0319] SB149

[0320] N-(6-(4-((4-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)benzoyl)piperazin-l- yl)methyl)piperidine-l-carbonyl)benzo[d]thiazol-2-yl)-2-naphthamide: To an ice-chilled stirring solution of Intermediate 24 (84 mg, 0.160 mmol, 1 eq) in DMF (2 mL) were added, Compound 2 (62 mg, 0.177 mmol, 1.1 eq), DIPEA (0.84 mL, 0.482 mmol, 3 eq) and COMU (76 mg, 0.177 mmol, 1.1 eq). The resulting mixture was stirred at rt for 20 h. The solvent was removes in vacuo and the crude compound was purified using Isolera Biotage One Flash Chromatography (0,1% TFA, Acetonitrile, Methanol) to afford the subject compound as an off-white solid (17 mg, yield: 13%).1H NMR (400 MHz, DMSO-dg) 6 13.14 (s, 1H), 9.98 (s, 1H), 8.85 (s, 1H), 8.18 (d, 1H), 8.14 - 7.98 (m, 3H), 7.79 (s, 1H), 7.67 (dt, 2H), 7.45 (d, 1H), 7.34 (s, 4H), 6.47 (s, 2H), 4.89 (s, 2H), 4.13 (t, 2H), 3.59 (s, 1H), 2.19 (d, 12H), 1.81 (s, 3H), 1.62 (p, 3H), 1.37 (h, 3H), 1.11 (d, 2H), 0.90 (t, 3H).

[0321] EXAMPLE 8: PBMC cytokine production assay

[0322] The TLR7 and RIG-1 conjugated compounds of the invention were tested for their ability to induce cytokine production in human primary peripheral blood mononuclear cells (PBMCs).

[0323] PBMCs were isolated from whole blood by centrifugation with the Ficoll-Paque density gradient solution. After centrifugation, PBMCs were washed twice with PBS and resuspended in medium at 1.5 x 106cells / mL. To perform the assay, PBMCs were seeded on 96-well microtiter plates at 1.5 x 105cells per well and incubated at 37 °C in the presence of the compounds.

[0324] The compounds were prepared as follows: First, stock solutions of the conjugated compounds were prepared in DMSO at a 1 mM concentration. The working dilutions of the conjugated compounds in medium were then added directly to PBMCs to ensure a 1 pM final concentration.

[0325] Cell free supernatant were collected after 20 h of incubation and stored at -80 °C until tested. Cytokine concentrations were determined with the LEGENDplex HU Essential Immune Response Panel (Biolegend, San Diego, CA, USA) on an Attune NxT flow cytometer (Thermo Fisher Scientific, Waltham, MA, USA) in accordance with manufacturer's instructions. Standard curves were generated using recombinant cytokines contained in the kit. The data were analysed using the LEGENDplex Data Analysis Software Suite (BioLegend). The ability of conjugated compounds to induce cytokine production in PBMCs is demonstrated in Figure 1. SB77 was the tested conjugated compound of the invention. Medium was used as a negative control. Intermediary compounds SG43 and SB71 were used as TLR7 and RIG-1 agonists, respectively. The combination of SG43 and SB71 was employed to compare the activity of conjugated compounds against an unconjugated mixture of TLR7 and RIG-1 agonists.

[0326] EXAMPLE 9: PBMC cytotoxicity assay

[0327] The TLR7 and RIG-1 conjugated compounds of the invention were tested for their ability to activate the cytotoxic activity of peripheral blood mononuclear cells (PBMCs) towards cancer cell lines. The main effector fraction of PBMCs in this assay are natural killer (NK) cells, which play an essential role in the innate immune system through their direct cytotoxic activity against aberrant cells, especially tumour cells and virally infected cells. The flow cytometry-based method described hereafter measures the PBMC cytotoxic activity against target cancer cell lines by co-incubating PBMCs and cancer cells, which were pre-labelled by carboxyfluorescein succinimidyl ester (CFSE) to distinguish them from effector cells. Successful activation of effector cells by the tested compounds leads to higher degree of cell death in the target cell population.

[0328] Chronic myelogenous leukaemia K562 cells were used as target cells in the assay. K562 cells were precultured for at least 10 days before the assay was performed. Immediately prior to the addition of target cells to PBMCs, target cells were stained with CFSE at 2 pM for 15 minutes at 37 °C in the dark. Cells were then washed with medium and resuspended at 2 x 105cells / mL.

[0329] PBMCs were isolated from whole blood by centrifugation with the Ficoll-Paque density gradient solution. After centrifugation, PBMCs were washed twice with PBS and resuspended in medium at 4 x 106cells / mL. To perform the assay, PBMCs were seeded on 96-well microtiter plates at 4 x 105cells per well and cultured in duplicates at 37 °C for 20 h in the presence of the compounds.

[0330] The compounds were prepared as follows: First, stock solutions of the conjugated compounds were prepared in DMSO at a 1 mM concentration. The working dilutions of the conjugated compounds in medium were then added directly to PBMCs to ensure a 1 pM final concentration.

[0331] After incubating the PBMCs in the presence of compounds, 104CFSE-stained K562 cells were added to each well for a final 40:1 ratio of effector cells versus target cells. After 4 h of co-incubation, cells were stained with the SYTOX™ Blue (Invitrogen) nucleic acid stain and analysed with flow cytometry. Dead (SYTOX™ Blue stain positive) target cells were gated out of the CFSE positive population, providing the ratio of killed cells within the target cell population.

[0332] The ability of conjugated compounds to activate the cytotoxic activity of PBMCs against K562 target cells is demonstrated in Figure 2. SB77 and SB102 were the tested conjugated compounds of the invention. Medium was used as a control and the results are given as a ratio versus the control. Intermediary compounds SG43 and SB71 were used as TLR7 and RIG-1 agonists, respectively. The combination of SG43 and SB71 was employed to compare the activity of conjugated compounds against an unconjugated mixture of TLR7 and RIG-1 agonists. IL-2 (200 U / mL) was used as the positive control.

[0333] EXAMPLE 10: Antigen presentation of BMDCs to CD4+ and CD8+ T-lymphocytes The effect of the conjugated compounds of the invention on antigen presentation of mouse bone marrow derived dendritic cells (BMDCs) to T-lymphocytes was examined. After pre-treating BMDCs with selected compounds and ovalbumin (OVA), antigen presentation of OVA to either CD4+or CD8+OVA-specific T-lymphocytes was observed with flow cytometry by detecting the degree of activation and proliferation of affected T-lymphocytes.

[0334] Bone-marrow cells were isolated from the tibia of C57BL / 6 mice and cultured in Dulbecco's modified Eagle's medium supplemented with 10% heat-inactivated fetal bovine serum, 2 mM L-glutamine, 100 U / mL penicillin, 100 pg / mL streptomycin, and 20 ng / mL granulocyte-macrophage colony-stimulating factor for 7 days at 37 °C and 5% CO2.

[0335] CD4+and CD8+T cells were purified from splenocytes of OT II and OT I transgenic mice using CD4+and CD8+T-cell negative selection kits (Miltenyi Biotec, Germany), according to manufacturer instructions. Purified T cells were stained with CFSE and washed. Then, 5 x 104T cells were mixed in triplicate with 104BMDCs per well (pre-treated with compounds [1 pM] or LPS [1 pg / mL] and 50 pg / mL OVA soluble protein for 18 h, and then washed). After 72 h of coincubation (37 °C, 5% CO2), the cells were stained with Fixable viability dye eFluor 780 (eBioscience, Thermo Fisher Scientific, MA, USA), anti-Thyl.2 PE- Cy7 (Biolegend, San Diego, CA, USA), anti-CD8 eFluor450 (eBioscience), anti-CD4 eFluor450 (eBioscience), and anti-CD25 APC antibodies (Biolegend) and analyzed using a Beckman Coulter Cytoflex S flow cytometer (CA, USA) and the FlowJo software (Tree Star, Inc., Ashland, OR, USA). Live Thyl.2+ / CD4+and Thyl.2+ / CD8+were evaluated for CFSE dilution and CD25 expression.

[0336] Figure 3 demonstrate the ratio of T-lymphocytes that divided during the co-culturing period. Medium was used as a negative control. LPS (1 pg / mL) was used as the positive control. Intermediary compounds SG43 and SB71 were used as TLR7 and RIG-1 agonists, respectively. The combination of SG43 and SB71 was employed to compare the activity of conjugated compounds against an unconjugated mixture of TLR7 and RIG-1 agonists.

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Claims

CLAIMS1. A compound having a structure according to Formula I:Formula I or a pharmaceutically acceptable salt, racemate, diastereomer, enantiomer, ester or prodrug thereof, wherein:• R1is H, halogen, OH, SH, CF3, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg-Cio aryl, 5-10 membered heterocyclyl, Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkyl, Ci-Cg alkoxy-Ci-Cg alkoxy, Ci-Cg alkoxy- (Ci-C6alkyl)S-, (Ci-C6alkyl)SO2NH-, (Ci-C6alkyl)C(=O)O-, (Ci-C6alkyl)OC(=O)-, (Ci-Cg alkyl)C(=O)-, (Ci-Cg alkyl)C(=O)NH-, RaRbN-, or RaRbN(C=O)-, wherein alkyl, alkoxy, cycloalkyl, aryl, and heterocyclyl may be optionally substituted;• R2is independently for each occurrence selected from H, halogen, OH, CHF2, CF3, CH2CF2, carboxy, CN, NO2, Ci-Cg alkyl, C3-C10 cycloalkyl, Ci-Cg alkoxy, (Ci-Cg alkyl)C(=O)-, (C6-Ci0aryl)C(=O)-, (Ci-C6alkyl)S-, (Ci-C6alkyl)C(=O)O-, (Ci-C6alkyl)OC(=O)-, (Ci-C6alkyl)C(=O)NH-, (Ci-Cg alkyl)SO2NH-, RaRbN-, and RaRbN(C=O)-, wherein alkyl, alkoxy, aryl, and cycloalkyl may be optionally substituted;• Raand Rbare independently from each other selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, Cg-Cio aryl and 5-10 membered heterocyclyl or Raland Rblmay together with the nitrogen atom form a 5-6 membered heterocycle, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;• X1is a single bond, -O-, -S-, -NRC-, -C(=O)- or -SO2-;• Rcis H, Ci-Cg alkyl or C3-C10 cycloalkyl;• L is a linking group;• n is 0, 1, 2, 3 or 4; and• R3is a RIG-1 agonist of Formula II:Formula II wherein:• X2is a single bond, -O-, -S-, -NRd-, -C(=O)- or -SO2-;• Rdis H, Ci-Cg alkyl, or C3-C10 cycloalkyl;• Y is N or CRe;• Reis H, Ci-Cg alkyl, or C3-C10 cycloalkyl;• R4is independently for each occurrence selected from H, halogen, CN, NO?, CF3, Ci-Cg alkyl, Cj-Cg alkenyl, C2-C6 alkynyl, C3-C10 cycloalkyl, Cg-Cio aryl, 5-10 membered heterocyclyl, -ORf, -SRf, -C(=O)Rf, -C(=O)NRgRh, -C(=O)ORf, -OC(=O)Rf, -OC(=O)NRgRh, -NRgR h, -NRfC(=O)Rf, -SORf, -SO?Rf, -SO2NRgRh, and -NRfSO?Rf, wherein alkyl, alkenyl, alkynyl, cycloalkyl, aryl, and heterocyclyl may be optionally substituted;• Rfis independently for each occurrence selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, C6- C10 aryl and 5-10 membered heterocyclyl, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;• Rgand Rhare independently from each other selected from H, Ci-Cg alkyl, C3-C10 cycloalkyl, C6-Cio aryl and 5-10 membered heterocyclyl or Rgand Rhmay together with the nitrogen atom form a 5-6 membered heterocycle, wherein alkyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted;• R5is H, Ci-Cg alkyl, or C3-C10 cycloalkyl;• R6is Ci-Cg alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C10 cycloalkyl, Cg-Cio aryl, or 5-10 membered heterocyclyl, wherein alkyl, alkenyl, alkynyl, cycloalkyl, aryl and heterocyclyl may be optionally substituted.

2. Compound according to claim 1, wherein n is 1.

3. Compound according to claim 1 or 2, wherein R1is H, Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkoxy, (Ci-C6alkyl)NH-, Ci-C6alkoxy-(Ci-C6alkyl)NH-, (Ci-C6alkyl)S- or CF3.

4. Compound according to any one of claims 1 to 3, wherein R1is Ci-Cg alkoxy, Ci-Cg alkoxy-Ci-Cg alkoxy, or (Ci-Cg alkyl ) N H-.

5. Compound according to any one of claims 1 to 4, wherein R1is n-BuO-.

6. Compound according to any one of claims 1 to 5, wherein R2is independently for each instance selected from H, halogen and Ci-Cg alkyl.

7. Compound according to claim 6, wherein R2is H in each instance.

8. Compound according to any one of claims 1 to 7, wherein X1is -O-, -NH- or -C(=O)-.

9. Compound according to any one of claims 1 to 8, wherein L is selected from the group consisting of an amino acid, a peptide, a non-peptidic polymeric linker and a non-polymeric aliphatic linker.

10. Compound according to claim 9, wherein L is a non-peptidic polymeric linker or a non-polymeric aliphatic linker.

11. Compound according to claim 10, wherein L is a polyethylene glycol chain comprising of 2 to 100 repeating ethylene glycol units.

12. Compound according to claim 11, wherein L is a polyethylene glycol chain comprising of 2, 3, 4, 5, 6, 7, 8, 9 or 10 repeating ethylene glycol units.

13. Compound according to claim 10, wherein L is a non-polymeric aliphatic linker.

14. Compound according to any one of claims 1 to 13, wherein X2is -O-, -NH- or -C(=O)-.

15. Compound according to any one of claims 1 to 14, wherein Y is N or CH.

16. Compound according to claim 15, wherein Y is N.

17. Compound according to any one of claims 1 to 16, wherein R4is H in each instance.

18. Compound according to any one of claims 1 to 17, wherein R5is H or Ci-Cg alkyl.

19. Compound according to claim 18, wherein R5is H.

20. Compound according to any one of claims 1 to 19, wherein R6is an optionally substituted Cg-Cio aryl or an optionally substituted 5-10 membered heterocyclyl.

21. Compound according to claim 20, wherein R6is an optionally substituted Cg-Cio aryl.

22. Compound according to claim 21, wherein R6is naftyl.

23. Compound according to any one of claims 1 to 22, wherein said compound is selected from the group consisting of:2-(2-naphthamido)-N-(2-(2-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethoxy)ethoxy)ethyl)benzo[d]thiazole-6-carboxamide,2-(2-naphthamido)-N-(l-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)phenyl)-l-oxo-6,9,12-trioxa-2-azapentadecan-15-yl)benzo[d]thiazole-6-carboxamide,2-(2-naphthamido)-N-(6-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)hexyl)benzo[d]thiazole-6-carboxamide,2-(2-naphthamido)-N-(2-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9- yl)methyl)benzamido)ethyl)benzo[d]thiazole-6-carboxamide, andN-(6-(4-((4-(4-((6-amino-2-butoxy-8-hydroxy-9H-purin-9-yl)methyl)benzoyl)piperazin-l- yl)methyl)piperidine-l-carbonyl)benzo[d]thiazol-2-yl)-2-naphthamide.

24. A process for preparing a compound of Formula I as defined in any one of claims 1 to 23 (with the variable groups being as defined in any one of claims 1 to 23) which comprises reacting a compound of Formula IX:Formula IX wherein R1, R2, X1, and n are as defined previously,with a compound of Formula X:Formula X, wherein R4, R5, R6, X2, Y, and L are as defined previously; or a compound of Formula XI:Formula XI wherein R1, R2, X1, L and n are as defined previously, with a compound of Formula XII:Formula XII wherein R4, R5, R6, X2, and Y are as defined previously; and optionally thereafter carrying out one or more of the following procedures:• removing any protecting groups,• forming a pharmaceutically acceptable salt,• converting a compound of Formula I into another compound of Formula I.

25. Compound of any one of claim 1 to 23 for use in medicine.

26. Compound of any one of claim 1 to 23 for use in treatment of a condition in which agonism of TLR7 and RIG-1 receptors is beneficial, wherein the condition is selected from the group consisting of viral infections, bacterial infections, fungal infections, protozoal infections, tumors, cancers and immunological diseases27. A pharmaceutical composition comprising a compound according to any one of claims 1 to 23 and one or more pharmaceutically acceptable excipients or carriers.

28. A vaccine comprising a compound according to any one of claims 1 to 23.

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