TITLE: GLYCOMIMETIC BINDERS FOR L-SIGN Description Field of the invention The present invention relates to selective glycomimetic ligands for the L-SIGN receptor, which find application in the medical field and, in particular, in the prevention and treatment of viral infections, for example caused by SARS-CoV- 2, in the immunotherapy of liver tumors and in the treatment of immune diseases. State of the art The SARS-CoV-2 virus infects human cells by exploiting the interaction between the membrane protein ACE2 (angiotensin-converting enzyme 2) and Spike glycoprotein. The SARS-CoV-2 virus also employ some immune cells to increase its transmission capacity. More specifically, the Spike glycoprotein is able to interact with human receptors belonging to the lectin family, called "C-type lectin receptors" (CLRs), including DC-SIGN and L-SIGN. The CLRs receptors are located on the surface of immune cells and are widely present in the respiratory mucosa and lung tissue. The capture of the virus by the CLRs receptors does not induce direct cellular infection; however, DC-SIGN and L-SIGN are able to retain the virus and transmit it to the permissive cells on which the ACE2 membrane protein is present, promoting the trans-infection of the virus itself. The virus transmission processes mediated by CLR receptors can be inhibited by using molecules that mimic the glycans present on the surface of the virus (glycomimetics). The DC-SIGN receptor is expressed in immature dendritic cells. In contrast, the L-SIGN receptor is expressed in type II alveolar cells and endothelial cells of the human lung and liver, and is co-expressed with ACE2 in respiratory tract cells. Therefore, in therapies to counter SARS-CoV-2 infection, L-SIGN is a more relevant target than DC-SIGN. The same is true for numerous other antiviral therapies. For example, L- SIGN is known to be the preferred attachment factor for West Nile virus (Davis et al J. Virol. 2006, 1290). To date, there are no selective glycomimetic molecules for the L-SIGN receptor with respect to DC-SIGN. Therefore, the problem behind the present invention is to develop glycomimetic molecules that selectively bind to L-SIGN and do not interact effectively with DC-SIGN. Summary of the invention The problem set out above is solved by a new class of glycomimetic molecules, as outlined in the attached claims, the definitions of which forms an integral part of the present description. Surprisingly, it has been found that these molecules, despite being closely related to a chemotype that contains active DC-SIGNB ligands, possess a high selectivity for the L-SIGN receptor. Thus, they can be effective in the prevention and treatment of infections by viruses that preferentially bind to the L-SIGN receptor. They can also be employed as targeting agents of drugs and vaccines towards liver endothelial cells (LSECs) expressing the L-SIGN receptor. Further characteristics and advantages of the invention will become clearer in the description of some embodiment examples, given hereinafter by way of indication and not of limitation. Brief description of the figures Figure 1 illustrates the results of the competition experiments performed by Surface Plasmon Resonance for the glycomimetic ligands identified in the experimental part of the present application as compounds 106a, 113, 115 and 119 (in accordance with the invention), the molecule identified in the experimental part as compound 103 and mannose (comparison examples). Figure 2 illustrates the data concerning the Isothermal Titration Calorimetry experiments carried out on the glycomimetic ligand identified in the experimental part of the present application as compound 106a (in accordance with the invention); Figure 3 shows the results of the direct interaction experiments performed by Surface Plasmon Resonance for the ligands identified in the experimental part of the present application as compounds 133 and 135 (in accordance with the invention). Detailed description of the invention The object of the present invention is a compound of formula (I) or a salt thereof, in which R is selected from the group consisting of: C ₁ - C ₆ alkyls, C ₃ -C ₆ cycloalkyls _, C ₆ -C ₁₀ aryls, -R ² Cl, -R ³ NH ₂ , - R ⁴ NHC(O)R’, -R ⁵ SR’’, -R ⁶ OR’’, and where: p is an integer from 0 to 3; q is an integer from 1 to 3; R ² _, R ³ _, R ⁴ _, R ⁵ _, R ⁶ are divalent radicals selected from the group consisting of C1 -C6 alkylenes and C3-C6 cycloalkylenes, preferably C2alkylenes having formula -CH2CH2-, and R', R'' are selected from the group consisting of C ₁ -C ₆ alkyls _, C ₃ -C ₆ cycloalkyls and C ₆ -C ₁₀ aryls, R''' is selected from the group consisting of -OH and halogens, preferably Cl, and in which R ¹ has formula (II): where: X is selected from the group consisting of CH ₂ , O, NH and S; Y is selected from the group consisting of O, NH and S; n is an integer between 0 and 3; m is an integer from 0 to 3, preferably 0; W is a heterocyclic substituent W1 selected from the group consisting of: or it is a substituent W2 having general formula: where: X1 is selected from the group consisting of H and C1-C6 alkyls preferably H or methyl; Z is selected from the group consisting of S and NRa, in which R _a and R _b are independently selected from the group consisting of H, COR ⁷ , COOR ⁸ , CONHR ⁹ , where R ⁷ , R ⁸ and R ⁹ are H, C1-C6alkyls,C3-C6 cycloalkyls or C6-C10 aryls. The present invention also relates to a compound of formula (IA) or a salt thereof, in which:

where R ¹ , p and q are as defined above. Said compound of formula (IA) is a dimer of the above compound of formula (I). Preferably, the R group of the compound of formula (I) is -R ² Cl, more preferably -CH2CH2Cl. According to a first embodiment, the group R ¹ has formula (II-A): (II-A) wherein when n = 0, X is CH2. In accordance with this embodiment, preferably, X is CH ₂ and Y is selected from NH, S and O. Preferably, n = 0 and/or m = 0. Preferably, Ra= H and/or Rb= H. In accordance with another embodiment, preferred compounds of formula (I) are those compounds wherein: - the substituent R ¹ has the formula (II-A) wherein n and m are 0, X is CH ₂ , Y is NH and Ra = Rb = H or Ra and Rb form, together with the heteroatoms to which they linked, an imidazole or imidazoline or benzimidazole or tetrahydropyrimidine moiety, that can be unsubstituted or substituted with a substituent preferably selected from alkyl, alkoxy, halogen, cycloalkyl, cycloalkoxy, aryl and heteroaryl; - the substituent R is a group -CH ₂ CH ₂ Cl. In accordance with this embodiment, the compound of formula (I) has the following formula: or it is a salt thereof, preferably a salt of hydrochloric acid or a salt of trifluoroacetic acid (TFA): In accordance with an embodiment, the group R ¹ has formula (II-A) wherein: n ≠0, X = NH, m = 0, Y = NH. Preferably, Ra = H and/or R _b = H. Preferably, n = 1. According to a second embodiment, the group R ¹ has formula (II-B): where when n = 0, X is CH2. Preferably, n = 0, X = CH2, m = 0, Y = NH, R _b = H. According to a third embodiment, the group R ¹ has formula (II-C): where when n = 0, X is CH ₂ . In accordance with this embodiment, preferably, X is CH2 and Y = NH. Preferably, n = 0 and/or m = 0. According to different embodiments, the compound (I) according to the present invention is selected from those reported in table 1 below. Table 1

Preferably, the compound (IA) is in the form of a salt, preferably a salt of hydrochloric acid or a salt of trifluoroacetic acid (TFA). Preferably, the compound (IA) has the formula: where X- = Cl- or CF ₃ COO-. The present invention also includes compound (I) and compound (IA), as well as their respective salts, for medical use. In the following description, the expressions "compound (I)" and "compound (IA)" also refer to the salts of the respective compounds. Compound (I) and compound (IA) act as selective inhibitors of the L-SIGN receptor. According to one embodiment, compound (I) and compound (IA) are advantageously employed for medical use in the prevention and/or treatment of virus infections which exploit ACE2 as a receptor to enter the target cell. According to one embodiment, said viruses are the viruses of the Orthocoronavirinae subfamily. For example, said viruses are the SARS-CoV2 virus and its variants. For example, these variants are the WT variants: Wuhan variant, UK: United Kingdom variant (B.1.1.7), SA: South African variant (B.1.53) and BR: Brazilian variant (P.1). According to further embodiments, said viruses include: West Nile virus (WNV), or hepatitis C virus (HCV), or Zika virus (Zikv), or Ebola virus. Also, object of the present invention are compound (I) and compound (IA) for medical use in the immunotherapy of liver tumors and/or in the treatment of immune diseases, in which said compounds act as targeting agents of drugs to liver sinusoidal endothelial cells (L-SEC) expressing the L-SIGN receptor. The targeting agents and drugs can be comprised in non-covalent formulations (e.g., liposomes and the like) or the carriers can be covalently linked to the drug using functional elements in the -OR group. The synthetic methodologies of compounds (I) and (IA) according to the present invention are reported below. METHOD OF SYNTHESIS NO. 1 A method is described for preparing the compound of formula (I), or a salt thereof, in which R ¹ is selected from the group consisting of: in which: X = CH ₂ , Y = NH, R _a = H, R _b = H, n and m are as defined above. Said method comprises a nucleophilic substitution reaction between the amino precursor of formula (III):

where r is an integer between 1 and 7, preferably 1, and a molecule having the formula: wherein Hal is a halogen, preferably chlorine or bromine, or other leaving group in nucleophilic substitution reactions. Said amino precursor (1.0 eq) and said molecule comprising a leaving group (1.4 eq) are dissolved in a high boiling solvent, for example DMF, DMSO, NMP, DMA or sulfolane (the concentration of the amino precursor is 0.1-0.5 M), and mixed at a temperature between 80 and 100°C until completion of the reaction, monitored by TLC. The reaction product is purified by flash chromatography. According to an embodiment of the invention, the compound (I) in which R ¹ has formula (II-A) is in the form of salt and the method for its synthesis comprises a nucleophilic substitution reaction between the amino precursor of formula (III) and formamidine hydrochloride having the formula: As an alternative to the method described above, the compound (I) in which R ¹ has formula (II-A) can be prepared in accordance with the synthetic methodologies illustrated in the experimental part of the present application. The amino precursor of formula (III) can be obtained starting from an azide 1 according to the following reaction scheme (SCHEME 1): An experimental procedure for obtaining the aforementioned compound is described below in accordance with SCHEME 1. A 0.04 M CuSO ₄ ∙5H ₂ O solution and a 0.16 M Na-ascorbate solution are prepared in deoxygenated water. A 0.4 M solution of alkyne 2 and a 0.4 M solution of azide 1 are prepared in deoxygenated THF. To the solution of the alkyne 2 (1 mol eq) are added, in sequence: 0.1 mol eq of the CuSO ₄ ∙5H ₂ O solution; 0.4 mol eq of the Na-ascorbate solution; 1 mol eq of the azide 1 solution. The reaction mixture is stirred at room temperature, under N2 and protected from light. At the end of the reaction, monitored by TLC, the solvents are evaporated and the crude triazole 3 is purified by automated flash chromatography to obtain a white foam. Triazole 3 is dissolved in anhydrous methanol, then a freshly prepared 0.1 M NaOMe solution is added. The reaction mixture is stirred at room temperature for one hour. Upon completion (monitoring by TLC), the reaction is neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated under vacuum. The crude product is dissolved in a 4:1 mixture of anhydrous CH2-Cl2 and TFA. The reaction is stirred at room temperature, under N2for one hour. At the end of the reaction (monitoring by TLC), the mixture is concentrated under vacuum and co-evaporated with toluene three times to obtain the amino precursor (III) as the TFA salt. METHOD OF SYNTHESIS NO. 2 A method is described for preparing the compound of formula (I), or a salt thereof, in which R ¹ is: (II-A) in which: X = CH2; Y = S or O; Ra= H; Rb= H, n and m are as defined above. As shown in the reaction scheme below (SCHEME 2), said method comprises a cycloaddition reaction between azide 1 and a terminal alkyne 4 to give the corresponding triazole 5; an addition reaction between triazole 5 and cyanamide to give compound 6; deacetylation of compound 6 to give product 7. SCHEME 2 in which: r is an integer between 1 and 7, preferably 1, Y is S or O. An experimental procedure for obtaining the aforementioned compound in accordance with SCHEME 2 is described below. A 0.04 M CuSO4∙5H2O solution and a 0.16 M Na-ascorbate solution are prepared in deoxygenated water. A 0.4 M solution of the terminal alkyne 4 and a 0.4 M solution of azide 1 in are prepared deoxygenated THF. To the solution of the terminal alkyne 4 (1.0 mol eq) are added, in sequence: 0.1 mol eq of the CuSO4∙5H2O solution; 0.4 mol eq of the Na-ascorbate solution; 1 mol eq of the azide 1 solution. The reaction mixture is stirred at room temperature, under N2and protected from light. At the end of the reaction, monitored by TLC, the solvents are evaporated and the crude product is purified by flash chromatography to obtain pure triazole 5. When Y = O: a mixture of triazole 5 (2.0 eq), cyanamide (1.2 eq) and anhydrous p-toluenesulfonic acid (1.3 eq) in anhydrous chloroform (1 M) is stirred under nitrogen until completion of the reaction; the mixture is then neutralized with triethylamine and the solvent removed at reduced pressure, the crude product is purified by flash chromatography to obtain compound 6. When Y = S: a catalytic amount of triethylamine (0.1 eq) is added to a mixture of triazole 5 (1.0 eq) and cyanamide (1.2 eq) in diethyl ether (1 M). After 2 hours of reflux, the reaction mixture is cooled to room temperature and stirred to completion (TLC monitoring); the solvent is then removed under reduced pressure and the crude product purified by flash chromatography to obtain compound 6. To a solution of product 6 (1.0 eq) in dry methanol (where Y is O or S) a freshly prepared 0.1 M NaOMe solution in dry methanol is added to a 0.05 M final concentration of the substrate (0.014 M final concentration of NaOMe). The reaction mixture is stirred at room temperature, under N2for one hour. Upon completion (TLC monitoring), the reaction is neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated in vacuo to obtain the pure product METHOD OF SYNTHESIS NO. 3 A method is described for preparing the compound of formula (I), or a salt thereof, in which R ¹ is: (II-A) in which: X = CH ₂ or NH, m = 0, Y = NH, with the condition that when n = 0, X is CH ₂ ; R _a = H, R _b = H; n and m are as defined above. Said method comprises an addition reaction between 1,3- Di-Boc-2-(trifluoromethylsulfonyl)guanidine and compound 8 to give compound 9; a cycloaddition reaction between azide 1 and compound 9 to give triazole 10; deacetylation of compound 10 to give compound 11; removal of the Boc protecting group with an acid to give product 12, as shown in the following reaction scheme (SCHEME 3):

SCHEME 3 where r is an integer between 1 and 7, preferably 1, o is an integer selected between 0 and 1, preferably, X- is Cl- or CF3COO-. An experimental procedure for obtaining the above compound is described below in accordance with SCHEME 3. 1,3-Di-Boc-2-(trifluoromethylsulfonyl)guanidine (0.9 eq) is dissolved in anhydrous dichloromethane (0.2 M), then triethylamine (1 eq) and compound 8 (1 eq) are added; examples of compound 8 are propargylamine and propargylhydrazine. The reaction mixture is stirred at room temperature, under nitrogen. Once the reaction is completed (TLC monitoring), the mixture is concentrated under vacuum and purified by flash chromatography to obtain compound 9. A 0.04 M CuSO4∙5H2O solution and a 0.16 M Na-ascorbate solution are prepared in deoxygenated water. A 0.6 M solution of compound 9 and a 0.4 M solution of azide 1 are prepared in deoxygenated THF. To the solution of compound 9 (1.5 mol eq) are added, in sequence: 0.1 mol eq of the CuSO4∙5H2O solution; 0.4 mol eq of the Na-ascorbate solution; 1 mol eq of the azide 1 solution. At the end of the reaction, monitored by TLC, the solvents are evaporated and the crude product is purified by flash chromatography to obtain pure triazole 10. To a solution of triazole 10 (1.0 eq) in anhydrous methanol, a freshly prepared 0.1 M NaOMe solution in anhydrous MeOH is added until a final concentration of 0.05 M of the substrate is reached (final concentration of NaOMe of 0.014 M). The reaction mixture is stirred at room temperature, under N2for one hour. Upon completion (TLC monitoring), the reaction is neutralized with Amberlite® IR120 hydrogen form ion- exchange resin, filtered and concentrated under vacuum to obtain the pure product 11. When X- = CF ₃ COO-: compound 11 (1 eq) is dissolved in a 4: 1 mixture of anhydrous CH2 Cl2 and TFA (0.05 M). The reaction mixture is stirred at room temperature, under N2 for 5 hours. Upon completion (TLC monitoring), the mixture is concentrated under vacuum and co-evaporated with toluene three times to obtain pure product 12. When X- = Cl-: compound 11 (1 eq.) is dissolved in CH2Cl2 (0.04 M); then 3 mol eq are added of a 1 M aqueous solution of HCl. The reaction mixture is stirred at room temperature for 3 days. Upon completion (TLC monitoring), the mixture is concentrated under vacuum and co-evaporated with toluene three times to obtain pure product 12. METHOD OF SYNTHESIS NO. 4 A method is described for preparing the compound of formula (I), or a salt thereof, in which R ¹ is: in which: X = CH ₂ or NH, m = 0, Y = NH, with the condition that when n = 0, X is CH ₂ , Ra and/or Rb are independently selected from COR ⁷ , COOR ⁸ , CONHR ⁹ , where R ⁷ , R ⁸ and R ⁹ are as defined above. Said method provides for the synthesis of compound 11 as described with reference to the previous SCHEME 3; compound 11 is reacted with a nucleophilic agent to give compound 13, which is subsequently subjected to removal of the protective group Boc with an acid to give product 14a/14b (tautomers), as shown in the following reaction scheme (SCHEME 4):

SCHEME 4 in which: r is an integer between 1 and 7, preferably 1, o is an integer selected between 0 and 1, RNu is a nucleophilic agent, in which: R is H, a C1-C6alkyl, C3-C 6cycloalkyl or a C6-C10aryl, and Nu is for example S-, O-, -NH ₂ , preferably, X- is Cl- or CF ₃ COO-. As a nucleophilic agent, a Grignard reagent can also be employed. An experimental procedure for obtaining the aforesaid compound in accordance with SCHEME 4 is described below. Compound 11 is obtained in accordance with the description provided regarding SCHEME 3, which will not be repeated here. A solution of compound 11 (1 eq) and nucleophilic agent (2 eq) in refluxed THF (0.3 M) is stirred until reaction is complete (TLC monitoring). The resulting solution is then concentrated under reduced pressure and the crude product purified by flash chromatography to obtain compound 13. When X- = CF3 COO-: compound 13 (1 eq.) is dissolved in a 4:1 mixture of anhydrous CH ₂ Cl ₂ and TFA (0.05 M). The reaction mixture is stirred at room temperature, under N ₂ for 5 hours. Upon completion (TLC monitoring), the mixture is concentrated under vacuum and co-evaporated with toluene three times to obtain the product 14a/14b (tautomers). When X- = Cl-: compound 13 (1 eq.) is dissolved in CH ₂ Cl ₂ (0.04 M); then 3 mol eq are added of a 1 M aqueous solution of HCl. The reaction mixture is stirred at room temperature for 3 days. At the end of the reaction (TLC monitoring), the mixture is concentrated under vacuum and co-evaporated with toluene three times to obtain the product 14a/14b (tautomers). A specific example of the above method is reported below, in which compound 11 reacts with the nucleophilic agent RNH ₂ to give compound 13', which in turn is treated in an acidic environment to give the amidinourea 14a'/14b' (tautomers), according to the following reaction (SCHEME 4A). The reaction conditions are as reported above.

SCHEME 4A METHOD OF SYNTHESIS NO. 5 A method is described for preparing the compound of formula (I), or a salt thereof, in which R ¹ is: where X = CH ₂ , Y = NH, R _b = H. Said method comprises an addition reaction between alkyne 15 and ammonium thiocyanate to give compound 16; a cycloaddition reaction between compound 16 and azide 1 to give the corresponding triazole 17; a deacetylation reaction to give product 18, as shown in the following reaction scheme (SCHEME 5).

SCHEME 5 where r is an integer between 1 and 7, preferably 1. An experimental procedure for obtaining the aforementioned compound accordance with SCHEME 5 is described below. Compound 15 (1.0 eq) is dissolved in water (2 M) and 3 eq of concentrated HCl; an example of compound 15 is propargylamine. The resulting solution is heated until dissolved, then cooled to room temperature. Ammonium thiocyanate (1.0 eq) is added to the solution and heated to 90°C overnight. At the end of the reaction (monitoring by TLC), the solution is cooled to room temperature and concentrated under reduced pressure. The crude product is purified by flash chromatography to obtain compound 16. A 0.04 M CuSO ₄ ∙5H ₂ O solution and a 0.16 M Na-ascorbate solution are prepared in deoxygenated water. A 0.6 M solution of compound 16 and a 0.4 M solution of azide 1 are prepared in deoxygenated THF. To the solution of compound 16 (1.5 mol eq) are added, in sequence: 0.1 mol eq of the CuSO ₄ ∙5H ₂ O solution; 0.4 mol eq of the Na-ascorbate solution; 1 mol eq of the azide 1 solution. The reaction mixture is stirred at room temperature, under N2 and protected from light. At the end of the reaction, monitored by TLC, the solvents are evaporated and the crude product is purified by flash chromatography to obtain pure triazole 17. A freshly prepared 0.1 M NaOMe solution in anhydrous methanol is added to a solution of triazole 17 (1.0 eq) in anhydrous methanol until a final substrate concentration of 0.05 M is reached (final NaOMe concentration of 0.014 M). The reaction mixture is stirred at room temperature, under N ₂ . Upon completion (monitoring by TLC), the reaction is neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated under vacuum to obtain pure product 18. METHOD OF SYNTHESIS NO. 6 A method is described for preparing the compound of formula (I), or a salt thereof, in which R is selected from the group consisting of C ₁ -C ₆ alkyls, C ₃ -C ₆ cycloalkyls _, C ₆ -C ₁₀ aryls, R ² Cl, where R ² is as defined above. Said method provides for the introduction of the aforementioned R group through the glycosylation reaction of an R-OH alcohol, preferably primary, with the 2-azido mannosyl donor 19a, as reported in the following reaction scheme (SCHEME 6A). SCHEME 6A An experimental procedure for obtaining azide 1 in accordance with SCHEME 6A, in which ROH is 2-chloroethanol (R = -CH2CH2Cl), is described below. Compound 19a (1.0 eq) is dissolved in anhydrous CH2Cl2 (concentration of compound 19a = 0.5 M), then 2-chloroethanol (2.0 eq) is added. The reaction mixture is cooled to 0° C, then BF3 ∙Et2O (4.0 eq) is added. The reaction is stirred at room temperature, under N2overnight. At the end of the reaction (monitoring by TLC), the mixture is extracted twice with cold water, once with a saturated solution of NaHCO ₃ and once again with cold water. The organic phase is dried over Na ₂ SO ₄ , filtered and concentrated under vacuum. The crude product is purified by automated flash chromatography. Alternatively, the aforementioned R-OH alcohol glycosylation reaction can use the donor 2-azido mannosyl 19b as reagent, as reported in the following reaction scheme (SCHEME 6B). SCHEME 6B An experimental procedure for obtaining azide 1 according to SCHEME 6B, in which ROH is 2-chloroethanol (R = -CH2CH2Cl), is described below. Compound 19b (1.0 eq) and activated and powdered molecular sieves 4A are co-evaporated with toluene three times and left under vacuum overnight. The mixture is then dissolved in anhydrous CH2Cl2 (concentration of compound 19b = 0.1 M), 2- chloroethanol (1.0 eq) is added and the solution is cooled to -30°C; then TMSOTf (0.2 eq) is added. The mixture is stirred at -30°C until completion (TLC monitoring). Upon completion, the mixture is quenched with TEA (0.4 eq) and concentrated under vacuum. The crude product is purified by flash chromatography. The azide 1 resulting from the aforementioned alcohol glycosylation reactions is subjected to the methods 1-5 described above, to obtain the compound according to the invention. METHOD OF SYNTHESIS NO. 7 A method is described for preparing the compound of formula (I), or a salt thereof, wherein R is -R ³ NH2, wherein R ³ is as defined above. Said method provides for the formation of azide 21 from the respective chloride 20 and the reduction of azide 21 to amine 22, in accordance with SCHEME 7, which gives the specific example in which R ³ is a C1-C6alkylene (with z integer between 1 and 6). The chloride 20 can be obtained with the method of SCHEME 6A or 6B. SCHEME 7 An experimental procedure for obtaining the amine 22 in accordance with SCHEME 7 is described below. Compound 20 (1.0 eq) is dissolved in anhydrous DMF, then NaN3 (5.0 eq) is added. The reaction mixture is stirred at 55°C for 3 days. At the end of the reaction (monitoring by ¹ H-NMR), the mixture is concentrated under vacuum and the crude compound 21 purified by automated flash chromatography to obtain pure compound 21. Compound 21 (1.0 eq) is dissolved in anhydrous methanol (concentration of compound 21 = 0.05 M) and 10% Pd/C or Pd Lindlar is added. The reaction is stirred in an atmosphere of H ₂ (1 atm) at room temperature. At the end of the reaction (monitoring by TLC), the catalyst is filtered on celite and the solvent is evaporated under reduced pressure to obtain pure product 22. The product 22 is then subjected to deacetylation with a NaOMe solution, in accordance with the procedure described above in relation to SCHEMES 2-5. In the synthesis method according to SCHEME 7, as a starting substrate, as an alternative to the acetylated compound 20, it is possible to use the corresponding deacetylated molecule. As an alternative to the method according to SCHEME 7, it is possible to introduce the aforementioned R group starting from a reaction intermediate, for example in accordance with the following reaction scheme (SCHEME 7A):

SCHEME 7A In the example illustrated in the above scheme, the intermediate 20a reacts with NaN3 to give the corresponding azide 21a, which is reduced to amine 22a. Subsequently, the compound 22a reacts according to the SCHEME 1 described above to give the amino precursor of formula (III) (not shown in the above scheme), which is then subjected to a nucleophilic substitution reaction according to the synthesis method no. 1 to give the reaction product. METHOD OF SYNTHESIS NO. 8 A method for preparing the compound of formula (I), or a salt thereof, is described, in which R is -R ⁴ NHC (O) R', in which R ⁴ and R' are as defined above. Said method provides for the reaction of the amine 22 obtained with the method of SCHEME 7 with an acyl chloride R'COCl or a carboxylic acid R'COOH, in accordance with SCHEME 8.

An experimental procedure for obtaining amide 23 in accordance with SCHEME 8 is described below. Reaction with R'COCl acyl chloride: sodium hydride (2.0 eq) is added at 0°C to a solution of compound 22 (1.0 eq) in 1,4-dioxane (concentration of compound 22 = 1.5 M), kept under stirring. Subsequently the acyl chloride (1.0 eq) is added dropwise. The resulting mixture is stirred at room temperature. At the end of the reaction (monitoring by TLC) the mixture is extracted with CH ₂ Cl ₂ and the organic phase is washed with water, then dried over Na ₂ SO ₄ , filtered and concentrated under vacuum. The crude product 23 is purified by flash chromatography to obtain the pure product 23. Reaction with carboxylic acid R'COOH: compound 22 (1.0 eq) is dissolved in anhydrous THF (0.2 M). Carboxylic acid (1.2 eq) and DCC (1.2 eq) are added in this order. The resulting mixture is stirred at room temperature under N2. At the end of the reaction (monitoring by TLC), the mixture is filtered on celite and washed with CH ₂ Cl ₂ . The crude product 23 is purified by flash chromatography to obtain the pure product 23. The product 23 is then subjected to deacetylation with a NaOMe solution, in accordance with the procedure described above in relation to SCHEMES 2-5. In the synthesis method according to SCHEME 8, as a starting substrate, as an alternative to the acetylated compound 22, it is possible to use the corresponding deacetylated molecule. As an alternative to the method according to SCHEME 8, it is possible to introduce the aforementioned R group starting from a reaction intermediate, for example in accordance with the following reaction scheme SCHEME 8A In the example illustrated in the above scheme, the intermediate 22a reacts with an acyl chloride or a carboxylic acid to give the amide 23a. Subsequently, the compound 23a reacts according to the SCHEME 1 described above to give the amino precursor of formula (III) (not shown in the above scheme), which is then subjected to a nucleophilic substitution reaction according to the synthesis method no. 1 to give the reaction product. METHOD OF SYNTHESIS NO. 9 A method is described for preparing the compound of formula (I), or a salt thereof, in which R is -R ³ NH2, -R ⁵ SR’’ or -R ⁶ OR'', in which R ³ , R ⁵ , R ⁶ e R'' are as defined above. Said method provides for a nucleophilic substitution reaction between compound 20 and a nucleophilic agent, in accordance with SCHEME 9, which gives the specific example in which R ³ , R ⁵ , R ⁶ is a C1-C6 alkylene (with z being an integer between 1 and 6): SCHEME 9 in which: RNu is a nucleophilic agent, in which: R is H, a C1-C6alkyl, a C3-C6cycloalkyl or a C6-C10aryl, and Nu is selected from S-, O- and -NH2. An experimental procedure for obtaining the product 24 in accordance with SCHEME 9, in which the nucleophilic agent is a thiolate, is described below. Compound 20 (1.0 eq) is dissolved in anhydrous DMF (0.2 M), then the corresponding thiol R''SH (5 eq) is added. The resulting reaction mixture is stirred at 55°C for 3 days. At the end of the reaction (monitoring by ¹ H-NMR), the mixture is concentrated under vacuum and the crude product 24 is purified by automated flash chromatography to obtain pure product 24. The product 24 is then subjected to deacetylation with a NaOMe solution, in accordance with the procedure described above in relation to SCHEMES 2-5. In the synthesis method according to SCHEME 9, as a starting substrate, as an alternative to the acetylated compound 20, it is possible to use the corresponding deacetylated molecule. As an alternative to the method according to SCHEME 9, it is possible to introduce the aforementioned R group starting from a reaction intermediate, for example in accordance with the following reaction scheme (SCHEME 9A), which reports the specific example in which the agent nucleophile is a thiolate:

SCHEME 9A In the example illustrated in the above scheme, the intermediate 20a reacts with the nucleophilic agent to give the compound 24a, which reacts according to the SCHEME 1 described above to give the amino precursor of formula (III) (not shown in the above scheme), which is then subjected to a nucleophilic substitution reaction according to the synthesis method no. 1 to give the reaction product. METHOD OF SYNTHESIS NO. 10 A method is described for preparing the compound of formula (I), or a salt thereof, in which R is where p, q and R''' are as defined above. Said method comprises the formation of an azide 26 starting from the corresponding chloride 25 in the presence of sodium azide; deacetylation of azide 26 to give compound 27; reaction of compound 27 with a terminal alkyne 28 to give product 29, as shown in the following reaction scheme (SCHEME 10): SCHEME 10 An experimental procedure for obtaining the product 29 in accordance with SCHEME 10 is described below. Compound 25 (1 eq) is dissolved in anhydrous DMF, then NaN3 (5 eq) is added. The reaction mixture is stirred at 55°C for 3 days. At the end of the reaction (monitoring by ¹ H-NMR), the mixture is concentrated under vacuum and the crude product is purified by automated flash chromatography to obtain pure compound 26 as a white foam. A freshly prepared 0.1 M NaOMe solution in anhydrous methanol is added to a solution of 26 (0.07 mmol) in anhydrous methanol until a final substrate concentration of 0.05 M is reached (final NaOMe concentration of 0.014 M). The reaction mixture is stirred at room temperature, under N ₂ for one hour. Upon completion (monitoring by TLC), the reaction is neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated under vacuum to obtain the pure product 27 as a white foam. A 0.01 M CuSO ₄ ∙5H ₂ O solution and a 0.04 M Na-ascorbate solution are prepared in deoxygenated water. A 0.04 M solution of alkyne 28 (according to Adibekian et al Nat. Chem. Biol. 2011, 7, 469), a 0.03 M solution of Tris [(1-benzyl-1H-1,2,3- triazol-4-yl) methyl] amine (TBTA) and a 0.2 M solution of compound 27 are prepared in deoxygenated THF. To the alkyne 28 solution (1 mol eq) are added, in sequence: 0.2 mol eq of the TBTA solution; 0.1 mol eq of the CuSO4∙5H2O solution; 0.4 mol eq of the Na-ascorbate solution. The mixture is stirred at room temperature for 10 minutes, then 1.0 mol eq of the compound 27 solution is added. The reaction mixture is stirred at room temperature in the dark overnight. At the end of the reaction (monitoring by TLC), the solvents are evaporated and the crude product purified by reverse-phase automated flash chromatography to obtain pure product 29 as a foam. As an alternative to the method according to SCHEME 10, it is possible to introduce the aforementioned R group starting from a reaction intermediate, for example in accordance with the following reaction scheme (SCHEME 10A):

In the example illustrated in the above scheme, the intermediate 25a reacts with NaN ₃ to give the corresponding azide 26a, which is deacetylated to give the compound 27a, which in turn reacts with the alkyne 28 to give the compound 29a. The latter is subjected to removal of the Boc protecting group with an acid to give the product 29, or it first reacts with a nucleophilic agent and then is subjected to removal of the Boc protecting group in accordance with SCHEME 4 to give the product 29. A further method for introducing the aforementioned R group uses the intermediate 25b as a starting substrate, in accordance with the following reaction scheme (SCHEME 10B): SCHEME 10B In the example illustrated in the above scheme, the intermediate 25b reacts with NaN ₃ to give the corresponding azide 26b, which is deacetylated to give the compound 27b. The latter is subjected to removal of the Boc protecting group with an acid to give compound 27b', which in turn reacts with 1,3-Di-Boc-2-(trifluoromethylsulfonyl)-guanidine to give compound 27a'. The latter reacts with the alkyne 28 to give the compound 29a'. The latter is subjected to removal of the Boc protecting group with an acid to give the product 29, or it first reacts with a nucleophilic agent and then is subjected to removal of the Boc protecting group in accordance with SCHEME 4 to give the product 29. A further method for introducing the aforementioned R group uses the intermediate 26b as a starting substrate, in accordance with the following reaction scheme (SCHEME 10C): SCHEME 10C In the example illustrated in the above scheme, the intermediate 26b reacts with alkyne 28 to give the compound 26c, which is deacetylated to give 27c. The latter is subjected to removal of the Boc protecting group with an acid to give compound 27c', which in turn reacts with 1,3-Di-Boc-2- (trifluoromethylsulfonyl)-guanidine to give compound 29b. The latter is subjected to removal of the Boc protecting group with an acid to give the product 29, or it first reacts with a nucleophilic agent and then is subjected to removal of the Boc protecting group in accordance with SCHEME 4 to give the product 29. METHOD OF SYNTHESIS NO. 11 A method is described for preparing the compound of formula (IA), or a salt thereof, which comprises a cycloaddition reaction between a terminal alkyne 30 and an azide 31 to give compound 32, as shown in the following reaction scheme (SCHEME 11). The azide 31 can be obtained starting from the respective chloride, as described for the synthesis method no. 10. SCHEME 11 in which: p is an integer from 0 to 3, q is an integer from 1 to 3, w is an integer selected between 0 and 1. An experimental procedure for obtaining product 32 in accordance with SCHEME 11 is described below. A 0.01 M CuSO4 ∙5H2O solution and a 0.04 M Na-ascorbate solution are prepared in deoxygenated water. A 0.04 M solution of alkyne 30 (according to Ordanini et al. Chem Comm 2015, 51, 3816), a 0.03 M solution of Tris[(1-benzyl-1H-1,2,3-triazol- 4-yl)methyl]amine (TBTA) and a 0.2 M solution of compound 31 are prepared in deoxygenated THF. To the solution of the alkyne 30 (1 mol eq) are added, in sequence: 0.2 mol eq of the TBTA solution; 0.1 mol eq of the CuSO ₄ ∙5H ₂ O solution; 0.4 mol eq of the Na-ascorbate solution. The mixture is stirred at room temperature for 10 minutes, then 2.2 mol eq of the solution of compound 31 are added. The reaction mixture is stirred under MW irradiation at 60°C. At the end of the reaction (monitoring by TLC), the solvents are evaporated and the crude product is purified by automated reverse phase flash chromatography with obtaining the pure product 32 as a yellow foam. As an alternative to the method according to SCHEME 11, it is possible to prepare compound (IA) starting from a reaction intermediate of compound (I), as will be better described in the experimental part. Experimental part Synthesis of compounds 106a and 106b: Compounds 106a and 106b were synthesized according to the following reaction scheme: Synthesis of compound 100: The 2-deoxy-2-azido-1,3,4,6-tetra-O-acetylmannose (prepared according to Medve et al Chem Eur. J. 2019, 14659; 5.6 g, 15.0 mmol, 1 eq.) was dissolved anhydrous CH2Cl2(17 mL) and 2-chloroethanol (2 mL, 30.0 mmol, 2 eq.). The mixture was cooled to 0°C, then BF ₃ ∙Et ₂ O (7.4 mL, 60 mmol, 4 eq.) was added slowly. The reaction was stirred at room temperature, under N ₂ for one night. Upon completion (TLC monitoring, toluene: AcOEt 7: 3, staining by ceric ammonium molybdate reagent), the mixture was extracted with cold H ₂ O (x2), saturated solution of NaHCO ₃ (x1) and cold H ₂ O (x1). The organic phase was dried over Na ₂ SO ₄ , filtered and concentrated under vacuum. The crude product was purified by automated flash chromatography (toluene with AcOEt gradient from 0% to 30%) to obtain the pure product 100 as a white foam (3.82 g, 65%). 1H-NMR (400 MHz, CDCl ₃ ): δ(ppm)= 5.39 (dd, 1H, J _3-4 = 9.7 Hz, J _2-3 = 3.8 Hz, H ₃ ), 5.32 (t, 1H, J _4-3 = J _4-5 = 9.7 Hz, H ₄ ), 4.89 (d, 1H, J1-2= 1.3 Hz, H1), 4.23 (dd, 1H, J6a-6b= 12.3 Hz, J6a-5= 4.9 Hz, H6a), 4.12-4.04 (m, 2H, H5 + H6b), 3.96-3.89 (m, 1H, H _7a ), 3.84-3.76 (m, 1H, H _7b ), 3.67 (t, 2H, J _8-7 = 5.5 Hz, H ₈ ), 2.10 (s, 6H, 2x OAc), 2.05 (s, 3H, OAc) 1 ³ C-NMR (400 MHz, CDCl ₃ ): δ(ppm)= 170.8 (CH ₃ CO), 170.0 (CH3CO), 169.7 (CH3CO), 98.7 (C1), 71.0 (C3), 68.9 (C5), 65.6 (C7), 65.9 (C4), 62.2 (C6), 61.5 (C2), 42.6 (C8), 20.8 (CH3CO), 20.7 (CH ₃ CO), 20.6 (CH ₃ CO) MS (ESI): m/z calculated for [C ₁₄ H ₂₀ ClN ₃ NaO ₈ ] ⁺ : 416.08 [M + Na] ⁺ , found: +68 ( ^^ = 2.0, CHCl ₃ ) Synthesis of compound 103: A 0.04 M CuSO4∙5H2O solution and a 0.16 M Na-ascorbate solution were prepared in deoxygenated water. A 0.4 M solution of N-Boc-propargylamine 101 and a 0.4 M solution of azide 100 were prepared in deoxygenated THF. To the solution of 101 (3.2 mL, 1.27 mmol, 1 mol eq), the following were added in sequence: 0.1 mol eq of the CuSO4∙5H2O solution (3.2 mL, 0.127 mmol), 0.4 mol eq of the Na-ascorbate solution (3.2 mL, 0.51 mmol), 1 mol eq of the solution of 100 (3.2 mL, 1.27 mmol). The reaction was stirred at room temperature, under N ₂ and protected from light. Upon completion (TLC monitoring Hex: AcOEt 6:4, Rf: 0.27), the solvents were evaporated. Crude product 102 was purified by automated flash chromatography (hexane with AcoEt gradient from 50% to 100%) to obtain a white foam (yield: 94%; R _f : 0.21 in Hex: AcoEt 1:1). Product 102 (50 mg) was dissolved in anhydrous MeOH (1 mL), a freshly prepared 0.1 M NaOMe solution in anhydrous MeOH (200 µL) was then added and the reaction stirred at room temperature for one hour. Upon completion (TLC monitoring CH ₂ Cl ₂ :MeOH 9:1), the reaction was neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated under vacuum. The crude was dissolved in a 4:1 mixture of anhydrous CH2Cl2 and TFA (2.3 mL). The reaction was stirred at room temperature, under N ₂ for one hour. Upon completion (TLC monitoring, CH ₂ Cl ₂ :MeOH 8:2), the mixture was concentrated under vacuum and co- evaporated with toluene three times to obtain the pure product 103 as TFA salt (white foam; 82% on two steps). Synthesis of compound 105: The TFA salt of 103 (38 mg, 0.087 mmol, 1 eq.) Was dissolved in H2O (725 µL) and diluted with 1,4-dioxane (3.6 mL), then 1 was added, 3-Di-Boc-2- (trifluoromethylsulfonyl)guanidine 104 (40.9 mg, 0.1 mmol, 1.2 eq). After five minutes, triethylamine (36 µL, 0.26 mmol, 3 eq) was slowly added and the reaction stirred at room temperature overnight. Upon completion (TLC monitoring, CH2Cl2:MeOH 9:1), the mixture was diluted with AcOEt and washed three times with brine. The organic phase was dried over Na ₂ SO ₄ , filtered and concentrated under vacuum. The crude was purified by automated flash chromatography (CH ₂ Cl ₂ with MeOH gradient from 0% to 20%) to obtain the pure product 105 as a white foam (30 mg, 61%). 1H-NMR (400 MHz, CD ₃ OD): δ(ppm)= 8.17 (s, 1H, H _TrCH ), 5.14 (s, 1H, H ₁ ), 5.09 (dd, 1H, J _2-3 = 5.3 Hz, J _2-1 = 1.1 Hz, H ₂ ), 4.65 (s, 2H, H ₉ ), 4.19 (dd, 1H, J _3-4 = 9.1 Hz, J _3-2 = 5.3 Hz, H3), 4.04 (m, 1H, H7a), 3.92-3.77 (m, 4H, H6 + H7b + H5), 3.76- 3.67 (m, 3H, H8 + H4), 1.52 (s, 9H, 3xCH3), 1.48 (s, 9H, 3xCH3). MS (ESI): m/z calculated for [C ₂₂ H ₃₈ ClN ₆ O ₉ ] ⁺ : 565.24 [M +H] ⁺ , found: 565.20; m/z calculated for [C ₂₂ H ₃₇ ClN ₆ NaO ₉ ] ⁺ : 587.22 [M + Na] ⁺ , found: 587.21; m/z calculated for [C ₂₂ H ₃₆ ClN6O9]- : 563.22 [M - H]-, found: 563.17 Synthesis of compound 106a: Compound 105 (47.4 mg, 0.083 mmol, 1 eq.) Was dissolved in a 4: 1 mixture of anhydrous CH ₂ Cl ₂ and TFA (1.66 mL). The reaction was stirred at room temperature, under N ₂ for 5 hours. Upon completion (TLC monitoring, CH2Cl2:MeOH 8:2), the mixture was concentrated in vacuo and co-evaporated with toluene three times to obtain the pure product 106a as a white foam (39 mg, 98%). 1H-NMR (400 MHz, CD ₃ OD): δ(ppm)= 8.22 (s, 1H, H _TrCH ), 5.15- 5.08 (m, 2H, H1 + H2), 4.49 (s, 2H, H9), 4.22 (dd, 1H, J3-4 = 9.2 Hz, J3-2 = 5.1 Hz, H3), 4.04 (m, 1H, H7a), 3.88 (d, 2H, J6-5 = 3 Hz, H ₆ ), 3.86-3.78 (m, 2H, H _7b + H ₅ ), 3.77-3.69 (m, 3H, H ₈ + H ₄ ). 1 ³ C-NMR (400 MHz, CD ₃ OD): δ(ppm)= 158.9 (C ₁₀ ), 158.8 (C _Trq ), 124.9 (CTrCH), 99.4 (C1), 75.1 (C5), 70.1 (C3), 69.3 (C7), 67.6 (C4), 65.4 (C2), 61.8 (C6), 43.8 (C8), 37.6 (C9). MS (HRMS): m/z calculated for [C ₁₂ H ₂₂ ClN ₆ O ₅ ] ⁺ : 365.1340 [M + H] ⁺ , found: 365.1337; m/z calculated for [C ₁₂ H ₂₁ ClN ₆ NaO ₅ ] ⁺ : 387.1159 [M+ Na] ⁺ , found: 387.1153.[ ^^] ² ^ _^ ⁷ = +10 ( ^^ = 0.5, MeOH) Synthesis of compound 106b: Compound 105 (36.3 mg, 0.064 mmol, 1 eq.) was dissolved in CH ₂ Cl ₂ (1.4 mL), then 190 µL of a 1M aqueous solution of HCl (3 eq) was added. The reaction was stirred at room temperature for 3 days. Upon completion (TLC monitoring, CH ₂ Cl ₂ :MeOH 8:2), the mixture was concentrated in vacuo and co-evaporated with toluene three times to obtain the pure product 106b as a white foam (22.7 mg, 88%). An alternative synthesis of intermediate 105 is reported below, according to the following reaction scheme: Synthesis of compound 108: 1,3-Di-Boc-2-(trifluoromethylsulfonyl)guanidine 104 (160 mg, 0.41 mmol, 0.9 eq) was dissolved in anhydrous dichloromethane (2.05 mL), then triethylamine (63 µL, 0.45 mmol, 1 eq) and propargylamine 107 (29 µL, 0.45 mmol, 1 eq). The reaction was stirred at room temperature, under nitrogen. Upon completion (TLC monitoring Hex:AcOEt 7:3), the mixture was concentrated in vacuo and purified by automated flash chromatography (hexane with AcOEt gradient from 0% to 30%) to obtain compound 108 as a white solid (89.3 mg, 73% product). H-NMR (400 MHz, CDCl): δ(ppm)= 11.43 (s, 1H, H), 8.43 (br s, 1H, H), 4.21 (dd, 2H, J = 4.9 Hz, J = 2.5 Hz, H), 2.25 (t, 1H, J = 2.5 Hz, H), 1.47 (s, 18H, 6xCH) MS (ESI): m/z calculated for [C H NNaO] : 320.16 [M + Na], found: 320.02; m/z calculated for [C H NO] : 290.16 [M - H], found: 295.99 Synthesis of compound 109: A 0.04 M CuSO4∙5H2O solution and a 0.16 M Na-ascorbate solution were prepared in deoxygenated water. A 0.6 M solution of 108 and a 0.4 M solution of 100 were prepared in deoxygenated THF. To the solution of 108 (375 µL, 0.23 mmol, 1.5 mol eq) were added, in sequence: 0.1 mol eq of the CuSO ₄ ∙5H ₂ O solution (375 µL, 0.015 mmol), 0.4 mol eq of Na-ascorbate solution (375 µL, 0.06 mmol), 1 mol eq of the solution of 100 (375 µL, 0.15 mmol). The reaction was stirred at room temperature, under N ₂ and protected from light. Upon completion (TLC monitoring Hex:AcOEt 6:4, Rf: 0.27), the solvents were evaporated and the crude product was purified by automated flash chromatography (hexane with AcOEt gradient from 0% to 70%) to obtain the pure triazole 109 as a white foam (96.7 mg, 93%). 1H-NMR (400 MHz, CDCl ₃ ): δ(ppm)= 11.44 (s, 1H, H ₁₁ ), 8.82 (t, 1H, J _10-9 = 4.8 Hz, H ₁₀ ), 7.98 (s, 1H. H _TrCH ), 5.51 (dd, 1H, J3-4 = 9.8 Hz, J3-2 = 5.2 Hz, H3), 5.41 (dd, 1H, J2-3 = 5.2 Hz, J2-1 = 0.9 Hz, H2), 5.26 (t, 1H, J4-3= 9.8 Hz, H4), 5.14 (s, 1H, H ₁ ), 4.82 (dd, 1H, J _9a-9b = 15.4 Hz, J _9a-10 = 5.6 Hz, H _9a ), 4.68 (dd, 1H, J _9b-9a = 15.4 Hz, J _9b-10 = 5.6 Hz, H _9b ), 4.33-4.17 (m, 3H, H ₆ + H ₅ ), 4.02-3.95 (m, 1H, H _7a ), 3.90-3.83 (m, 1H, H _7b ), 3.72 (t, 2H, J8-7 = 5.7 Hz, H8), 2.16 (s, 3H, OAc), 2.04 (s, 3H, OAc), 1.95 (s, 3H, OAc), 1.50 (s, 9H, 3xCH3), 1.48 (s, 9H, 3xCH ₃ ). MS (ESI): m/z calculated for [C ₂₈ H ₄₄ ClN ₆ O ₁₂ ] ⁺ : 691.27 [M + H] ⁺ , found: 691.58; m/z calculated for [C ₂₈ H ₄₃ ClN ₆ NaO ₁₂ ] ⁺ : 713.25 [M + Na] ⁺ , found: 713.54; m/z calculated for [C28H42ClN6O12]- : 689.25 [M - H]-, found: 689.65 Synthesis of compound 105: To a solution of 109 (50 mg, 0.07 mmol) in anhydrous MeOH (1.2 mL) a freshly prepared 0.1 M NaOMe solution in anhydrous MeOH (200 µL) was added to a final concentration of 0.05 M of the substrate (final NaOMe concentration of 0.014 M). The reaction was stirred at room temperature, under N ₂ for one hour. Upon completion (TLC CH ₂ Cl ₂ :MeOH 9:1 monitoring), the reaction was neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated under vacuum to obtain the pure product 105 as a white foam (37 mg, 94%). Compound 113 was synthesized according to the following reaction scheme: Synthesis of compound 111: A 0.04 M CuSO4 ^. 5H2O solution and a 0.16 M Na-ascorbate solution were prepared in deoxygenated water. A 0.4 M solution of 110 and a 0.4 M solution of 100 were prepared in deoxygenated THF. To the solution of 110 (800 µL, 0.32 mmol, 1 mol eq) were added, in sequence: 0.1 mol eq of CuSO4 ^. 5H2O solution (800 µL, 0.032 mmol), 0.4 mol eq of Na-ascorbate solution (800 µL, 0.128 mmol), 1 mol eq of the solution of 100 (800 µL, 0.32 mmol). The reaction was stirred at room temperature, under N ₂ and protected from light. Upon completion (TLC Hex:AcOEt 1:1, Rf(111): 0.20), the solvents were evaporated, and the crude product purified via automated flash chromatography (Hex with AcOEt gradient from 15% to 100%) to obtain the pure triazole 111 as a white foam (146 mg, 60%). 1H-NMR (400MHz, MeOD): δ(ppm)= 8.28 (m, 1H, HTrCH), 7.94 (m, 1H, H10), 7.64 (d, 1H, J12-13 = 7.1 Hz, H13), 7.37 (m, 2H, H11, H12), 5.46 (m, 1H, H3), 5.39 (m, 1H, H2), 5.29 (m, 1H, H4), 5.18 (m, 1H, H ₁ ), 5.11 (m, 2H, H ₉ ), 4.31 (m, 2H, H _6a,b ), 4.20 (m, 1H, H ₅ ), 4.05-3.96 (m, 1H, H _7a ), 3.92-3.84 (m, 1H, H _7b ), 3.79 (t, 2H, J8-7 = 6.6 Hz, H8), 2.03 (s, 3H, OAc), 1.85 (s, 3H, OAc), 1.50 (s, 3H, OAc), 1.71 (s, 9H, 3xCH3), 1.40 (s, 9H, 3x CH ₃ ). Synthesis of compound 112: The product 111 (100 mg) was dissolved in in dry MeOH (720 µL), a freshly prepared 1M NaOMe solution in dry MeOH was added (39 µL) and the reaction was stirred at room temperature for 2h. Upon completion (TLC CH ₂ Cl ₂ :MeOH 9:1), the reaction was neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated in vacuo to obtain the pure product 112 as a white foam (66 mg, 94%). 1H-NMR (400MHz, CD3OD): δ(ppm)= 8.12 (s, 1H, HTrCH), 7.47 (m, 2H, H _10,13 ), 7.15 (dd, 1H, J _11-12 = 6.1 Hz, J _11-13 = 2.8 Hz, H _11,12 ), 5.34 (s, 2H, H ₉ ), 5.08 (s, 1H, H ₁ ), 5.05 (d, J _1-2 = 5.2 Hz, 1H, H ₂ ), 4.15 (dd, 1H, J _3-2 = 9.7 Hz, J _3-4 = 4.0 Hz, H ₃ ), 4.03-3.95 (m, 1H, H7a), 3.85-3.70 (m, 6H, H5+H6a,6b+H7b+H8a,8b), 3.64 (t, 1H, H4), 1.54 (s, 9H, 3x CH3). Synthesis of compound 113: Compound 112 (66 mg, 0.12 mmol, 1 eq.) was dissolved in a 4:1 mixture of dry CH ₂ Cl ₂ and TFA (2.45 mL). The reaction was stirred at room temperature, under N2for 5h. Upon completion (TLC monitoring, DCM:MeOH 8:2) the mixture was concentrated in vacuo and co-evaporated with toluene three-times to obtain 113 as the TFA salt (white foam) (66.2 mg, 99%). 1H-NMR (400 MHz, CD ₃ OD): δ(ppm)= 8.29 (s, 1H, H _CHTr ), 7.43- 7.36 (m, 2H, H10,13), 7.34-7.27 (m, 2H, H11,12), 5.13 (m, 2H, H1+H2), 4.74 (s, 2H, H9a,9b), 4.22 (dd, 1H, J3-2 = 9.3 Hz, J3-4 = 4.1 Hz, H ₃ ), 4.05-3.97 (m, 1H, H _7a ), 3.87 (d, 2H, J _6-5 = 2.9 Hz, H _6a,6b ), 3.82-3.78 (m, 2H, H _7b +H ₅ ), 3.77-3.70 (m, 3H, H _8a,8b +H ₄ ). ¹³ C-NMR (400MHz, CD ₃ OD): δ(ppm)= 151.8 (C), 144.3 (C), 131.2 (CTrq), 125.3 (CTrCH), 125.2 (C11,12), 112.6 (C10,13), 99.8 (C1), 75.2 (C5), 70.3 (C3), 69.5 (C7), 67.7 (C4), 65.7 (C2), 61.9 (C6), 44.1 (C ₈ ), 39.4 (C ₉ ). MS (ESI): m/z calculated for [C ₁₈ H ₂₄ ClN ₆ O ₅ ] ⁺ : 439.87 [M + H] ⁺ , found: 439.41; m/z calculated for [C ₁₈ H ₂₄ ClN ₆ O ₅ ]- : 437.87 [M - H]- , found: 437.34. Compound 115 was synthesized according to the following reaction scheme: Synthesis of compound 115: A 0.04 M CuSO4 ^. 5H2O solution and a 0.16 M Na-ascorbate solution were prepared in deoxygenated water. A 0.4 M solution of 114 and a 0.4 M solution of 100 were prepared in deoxygenated THF. To the solution of 114 (1.63 mL, 0.65 mmol, 1 mol eq) were added, in sequence: 0.1 mol eq of CuSO ₄ ^. 5H ₂ O solution (1.63 mL, 0.065 mmol), 0.4 mol eq of Na-ascorbate solution (1.63 mL, 0.26 mmol), 1 mol eq of the solution of 100 (1.63 mL, 0.65 mmol). The reaction was stirred at room temperature, under N2 and protected from light. The reaction was monitored by NMR analysis. After 22h, the solvents were evaporated, the crude was dissolved in AcOEt and washed two times with NaOH 40 % (% m/V). The organic phase was then treated with HCl 1M (until pH = 1) and the solvents (AcOEt and water) were evaporated. The obtained chloride salt was purified via semi-preparative HPLC (H ₂ O with CH ₃ CN gradient from 0% to 50% + 0.1% Formic Acid) to give the pure formate 115 as a white foam (142 mg, 50%). 1H-NMR (400 MHz, CD ₃ OD): δ(ppm)= 8.21 (s, 1H, H _CHTr ), 5.12 (s, 2H, H1+ H2), 4.50 (s, 2H, H9a,b), 4.22 (dd, 1H, J3-2 = 9.6 Hz, J3-4 = 3.8 Hz, H3), 4.01 (m, 1H, H7), 3.88 (d, 2H, J6-5 = 4.0 Hz, H _6,6’ ), 3.86-3.71 (m, 9H, H _7’ +H ₅ +H ₄ +H _8,8’ +H _10,11 ). ¹³ C-NMR (400MHz, CD ₃ OD): δ(ppm)= 161.7 (C), 144.5 (C _Trq ), 125.0 (C _TrCH ), 99.8 (C ₁ ), 75.4 (C ₅ ), 70.8 (C ₃ ), 69.7 (C ₇ ), 67.9 (C ₅ ), 66.2 (C ₂ ), 62.2 (C6), 44.9-43.9 (C8+ C10 + C11), 39.0 (C9). MS (ESI): m/z calculated for [C14H24ClN6O5] ⁺ : 390.14 [M + H] ⁺ , found: 390.27; m/z calculated for [C ₁₄ H ₂₂ ClN ₆ O ₅ ]- : 388.14 [M - H]- , found: 388.21. Synthesis of compound 119:

Compound 119 was synthesized according to the following reaction scheme: solution were prepared in deoxygenated water. A 0.4 M solution of 116 and a 0.4 M solution of 100 were prepared in deoxygenated THF. To the solution of 116 (850 µL, 0.34 mmol, 1 mol eq) were added, in sequence: 0.1 mol eq of CuSO ₄ ^. 5H ₂ O solution (850 µL, 0.034 mmol), 0.4 mol eq of Na-ascorbate solution (850 µL, 0.136 mmol), 1 mol eq of the solution of 1 (850 µL, 0.34 mmol). The reaction was stirred at room temperature, under N2 and protected from light. Upon completion (TLC DCM:MeOH 95:5, R _f (117): 0.46), the solvents were evaporated, and the crude product purified via automated flash chromatography (DCM with MeOH gradient from 0% to 6%) to obtain the pure triazole 117 as a white foam (164 mg, 68%). 1H-NMR (400MHz, MeOD): δ(ppm)= 8.24 (m, 1H, H _TrCH ), 7.45 (m, 1H, H ₁₁ ), 6.89 (m, 1H, H ₁₀ ), 5.46 (m, 1H, H ₃ ), 5.39 (m, 1H, H2), 5.29 (m, 1H, H4), 5.25 (m, 1H, H1), 4.95-4.72 (m, 2H, H9), 4.31 (m, 1H, H5 + H6a,6b), 4.05-3.91 (m, 1H, H7a,b), 3.82 (t, 2H, J _8-7 = 6.6 Hz, H ₈ ), 2.19 (s, 3H, OAc), 2.05 (s, 3H, OAc), 1.90 (s, 3H, OAc), 1.60 (s, 9H, 3xCH ₃ ), 1.38 (s, 9H, 3x CH ₃ ). Synthesis of compound 118: The product 117 (146 mg) was dissolved in in dry MeOH (4 mL), a freshly prepared 0.1M NaOMe solution in dry MeOH was added (612 µL) and the reaction was stirred at room temperature for 4h. Upon completion (TLC CHCl ₃ :MeOH 9:1), the reaction was neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated in vacuo to obtain the pure product 118 as a white foam (102 mg, 99%). 1H-NMR (400MHz, CDCl ₃ ): δ(ppm)= 8.05 (s, 1H, H _TrCH ), 6.88 (s, 2H, H _10,11 ), 5.20-4.98 (m, 4H, H ₁ +H ₂ +H ₉ ), 4.18 (dd, 1H, J _3-4 = 10.0 Hz, J _3-2 = 4.0 Hz, H ₃ ), 4.02 (m, 1H, H _7a ), 3.94-3.72 (m, 6H, H5+H6a,b+H7b+H8a,b), 3.67 (t, 1H, H4), 1.50 (s, 9H, 3x CH3). Synthesis of compound 119: Compound 118 (102 mg, 0.21 mmol, 1 eq.) was dissolved in a 4:1 mixture of dry CH ₂ Cl ₂ and TFA (4.2 mL). The reaction was stirred at room temperature, under N ₂ for 3h. Upon completion (TLC monitoring, DCM:MeOH 8:2) the mixture was concentrated in vacuo and co-evaporated with toluene three-times to obtain 119 (TFA salt) as a white foam (105 mg, 99%). 1H-NMR (400 MHz, CD ₃ OD): δ(ppm)= 8.22 (s, 1H, H _CHTr ), 6.88 (s, 2H, H _10,11 ), 5.13-5.10 (m, 2H, H ₁ +H ₂ ), 4.58 (s, 2H, H ₉ ), 4.21 (dd, J3-2 = 9.6 Hz, J3-4 = 4.6 Hz 1H, H3), 4.01-3.97 (m, 1H, H7a), 3.90 (d, 2H, J6-5 = 3.2 Hz, H6), 3.82-3.76 (m, 2H, H7b+H5), 3.77-3.69 (m, 2H, H ₄ +H ₈ ). ¹³ C-NMR (400MHz, CD ₃ OD): δ(ppm)= 144.5 (C), 135.8 (C _Trq ), 124.7 (C _TrCH ), 115 (C _10,11 ) 99.5 (C ₁ ), 74.9 (C ₅ ), 70.2 (C ₃ ), 69.4 (C ₇ ), 67.7 (C ₄ ), 65.5 (C ₂ ), 61.9 (C ₆ ), 43.7 (C8), 39.1 (C9). MS (ESI): m/z calculated for [C14H22ClN6O5] ⁺ : 388.73 [M + H] ⁺ , found: 389.41; m/z calculated for [C ₁₄ H ₂₀ ClN ₆ O ₅ ]- : 386.73 [M - H]- , found: 386.32. Synthesis of intermediate 121: Intermediate 121 was synthesized according to the following reaction scheme: Synthesis of compound 120: Compound 109 (230 mg, 0.33 mmol, 1 eq) was dissolved in anhydrous DMF (1.65 mL), then NaN ₃ (106.5 mg, 1.64 mmol, 5 eq) was added and the reaction was stirred at 55°C for 3 days. Upon completion ( ¹ H-NMR monitoring), the mixture was concentrated in vacuo and the crude product was purified by automated flash chromatography (hexane with AcOEt gradient from 0% to 100%) to obtain the pure product 120 as a white foam. (60.2 mg, 26%). 1H-NMR (400 MHz, CDCl3): δ(ppm)= 11.44 (s, 1H, H11), 8.82 (t, 1H, J _10-9 = 4.6 Hz, H ₁₀ ), 7.98 (s, 1H. H _TrCH ), 5.49 (dd, 1H, J _3-4 = 9.9 Hz, J _3-2 = 5.2 Hz, H ₃ ), 5.41 (d, 1H, J _2-3 = 5.0 Hz, H ₂ ), 5.26 (t, 1H, J _4-3 = 10.0 Hz, H ₄ ), 5.13 (s, 1H, H ₁ ), 4.80 (dd, 1H, J9a-9b = 15.5 Hz, J9a-10 = 5.5 Hz, H9a), 4.66 (dd, 1H, J9b-9a = 15.5 Hz, J9b-10 = 5.5 Hz, H9b), 4.30 (dd, 1H, J6a-6b = 12.4 Hz, J _6a-5 = 4.0 Hz, H _6a ), 4.22-4.14 (m, 2H, H _6b + H ₅ ), 3.94-3.87 (m, 1H, H _7a ), 3.74-3.67 (m, 1H, H _7b ), 3.58-3.44 (m, 2H, H ₈ ), 2.14 (s, 3H, OAc), 2.02 (s, 3H, OAc), 1.93 (s, 3H, OAc), 1.48 (s, 9H, 3xCH3), 1.46 (s, 9H, 3x CH3). MS (ESI): m/z calculated for [C28H43N9NaO12] ⁺ : 720.29 [M + Na] ⁺ , found: 720.11. Synthesis of compound 121: To a solution of 120 (50 mg, 0.07 mmol) in anhydrous MeOH (1.2 mL) a freshly prepared 0.1 M NaOMe solution in anhydrous MeOH (200 µL) was added to a final concentration of substrate of 0.05 M (final NaOMe concentration of 0.014 M). The reaction was stirred at room temperature, under N ₂ for one hour. Upon completion (TLC CH ₂ Cl ₂ :MeOH 9:1 monitoring), the reaction was neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated under vacuum to obtain the pure product 121 as a white foam (37 mg, 92%). An alternative synthesis of intermediate 121 is reported below, according to the following reaction scheme: Synthesis of compound 122: Compound 102 (180 mg, 0.33 mmol, 1 eq) was dissolved in anhydrous DMF (1.65 mL), then NaN ₃ (106.5 mg, 1.64 mmol, 5 eq) was added and the reaction was stirred at 55°C for 3 days. Upon completion ( ¹ H-NMR monitoring), the mixture was concentrated in vacuo and the crude product was purified by automated flash chromatography (hexane with 30% to 70% AcOEt gradient) to obtain pure product 122 as a white foam (158 mg, 86%). 1H-NMR (400 MHz, CD3OD): δ(ppm)= 8.10 (s, 1H, HCHTr), 5.49 (dd, 1H, J _3-4 = 10.2 Hz, J _3-2 = 5.1 Hz, H ₃ ), 5.40 (d, 1H, J _2-3 = 5.1 Hz, H ₂ ), 5.32 (t, 1H, J _4-3 = 10.2 Hz, H ₄ ), 5.27 (s, 1H. H ₁ ), 4.41-4.32 (m, 3H, H _6a + H ₉ ), 4.30-4.19 (m, 2H, H _6b + H ₅ ), 4.01- 3.92 (m, 1H, H7a), 3.82-3.75 (m, 1H, H7b), 3.62-3.45 (m, 2H, H8), 2.16 (s, 3H, OAc), 2.05 (s, 3H, OAc), 1.89 (s, 3H, OAc), 1.45 (s, 9H, 3xCH ₃ ). MS (ESI): m/z calculated for [C ₂₂ H ₃₃ N ₇ NaO ₁₀ ] ⁺ : 578.22 [M + Na] ⁺ , found: 578.38. Synthesis of compound 123: To a solution of 122 (50 mg, 0.09 mmol) in anhydrous MeOH (1.5 mL) a freshly prepared 0.1 M NaOMe solution in anhydrous MeOH (270 µL) was added to a final concentration of substrate of 0.05 M (final NaOMe concentration of 0.015 M). The reaction was stirred at room temperature, under N ₂ for one hour. Upon completion (TLC CH2Cl2:MeOH 9:1 monitoring), the reaction was neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated under vacuum to obtain pure product 123 as a white foam (37.8 mg, 98%). 1H-NMR (400 MHz, CD ₃ OD): δ(ppm)= 8.06 (s, 1H, H _CHTr ), 5.12 (s, 1H, H1), 5.07 (d, 1H, J2-3= 4.7 Hz, H2), 4.31 (s, 2H, H9), 4.24-4.17 (m, 1H, H3), 4.01-3.82 (m, 3H, H7a + H6), 3.81-3.66 (m, 3H, H _7b + H ₄ + H ₅ ), 3.48 (t, 2H, J _8-7 = 4.6 Hz, H ₈ ), 1.45 (s, 9H, 3xCH ₃ ). MS (ESI): m/z calculated for [C ₁₆ H ₂₇ N ₇ NaO ₇ ] ⁺ : 452.19 [M + Na] ⁺ , found: 452.19; m/z calculated for [C ₃₂ H ₅₄ N ₁₄ NaO ₁₄ ] ⁺ : 881.38 [2M + Na] ⁺ , found: 881.01; m/z calculated for [C16H26N7O7] ⁺ : 428.18 [M - H]-, found 428.18. Synthesis of compound 124: Compound 123 (37.5 mg, 0.087 mmol, 1 eq.) was dissolved in a 9:1 mixture of anhydrous CH2Cl2 and TFA (1.77 mL). The reaction was stirred at room temperature, under N ₂ for an hour. Upon completion (TLC monitoring, CHCl ₃ :MeOH 8:2), the mixture was concentrated in vacuo and co-evaporated with toluene three times to obtain 124 as the TFA salt ( yellowish foam) (38.5 mg, quantitative). 1H-NMR (400 MHz, CD ₃ OD): δ(ppm)= 8.30 (s, 1H, H _CHTr ), 5.16- 5.11 (m, 2H, H ₁ + H ₂ ), 4.28-4.21 (m, 3H, H ₉ + H ₃ ), 4.01-3.93 (m, 1H, H _7a ), 3.90 (d, 2H, J _6-5 = 3.4 Hz, H ₆ ), 3.82-3.76 (m, 1H, H5), 3.75-3.66 (m, 2H, H4 + H6b), 3.53-3.46 (t, 2H, J8-7 = 4.7 Hz, H8). Synthesis of compound 121: The salt of TFA 124 (38 mg, 0.087 mmol, 1 eq.) was dissolved in H ₂ O (725 µL) and diluted with 1,4-dioxane (3.6 mL), then 1,3-Di-Boc-2-(trifluoromethylsulfonyl)guanidine 104 (40.9 mg, 0.1 mmol, 1.2 eq). After five minutes, triethylamine (36 µL, 0.26 mmol, 3 eq) was slowly added and the reaction stirred at room temperature overnight. Upon completion (TLC monitoring, CH ₂ Cl ₂ :MeOH 9:1), the mixture was diluted with AcOEt and washed three times with brine. The organic phase was dried over Na2SO4, filtered and concentrated under vacuum. The crude was purified by automated flash chromatography (CH ₂ Cl ₂ with MeOH gradient from 0% to 20%) to obtain the pure product 121 as a white foam (30 mg, 60%). 1H-NMR (400 MHz, CD3OD): δ(ppm)= 8.18 (s, 1H, HTrCH), 5.14 (s, 1H, H1), 5.09 (d, 1H, J2-3 = 5.2 Hz, H2), 4.65 (s, 2H, H9), 4.21 (dd, 1H, J _3-4 = 9.1 Hz, J _3-2 = 5.2 Hz, H ₃ ), 3.99-3.91 (m, 1H, H _7a ), 3.90-3.83 (m, 2H, H ₆ ), 3.81-3.67 (m, 3H, H ₄ + H ₅ + H _7b ), 3.48 (t, 2H, J _8-7 = 5.1 Hz, H ₈ ), 1.51 (s, 9H, 3xCH ₃ ), 1.48 (s, 9H, 3x CH3). Compound 121 was treated with trifluoroacetic acid or HCl, as described above for compound 105, obtaining the compounds collectively referred to as 121a. Synthesis of compound 130 Compound 130 was synthesized according to the following reaction scheme:

Synthesis of compound 126: A 0.04 M CuSO4∙5H2O solution and a 0.16 M Na-ascorbate solution were prepared in deoxygenated water. A 0.4 M solution of 125 (prepared according to Piron F. et al, Synthesis (Stuttg) 2010, 2010, 1639–1644) and a 0.4 M solution of 122 were prepared in deoxygenated THF. To the solution of 125 (2.75 mL, 1.1 mmol, 1 mol eq) were added, in sequence: 0.1 mol eq of the CuSO4∙5H2O solution (2.75 mL, 0.11 mmol), 0.4 mol eq of the Na-ascorbate solution (2.75 mL, 0.44 mmol) and 1.0 mol eq of the 122 solution (2.75 mL, 1.1 mmol) was added. The reaction was stirred at room temperature in the dark overnight. Upon completion (TLC monitoring CH2Cl2:MeOH 9:1), the solvents were evaporated and the crude product purified by automated flash chromatography (CH ₂ Cl ₂ with Acetone gradient from 5% to 100%) to obtain the pure product 126 as a foam (689.4 mg, 82%). 1H-NMR (400MHz, CD3OD): δ(ppm)= 8.09 (s, 1H, HTrCH’), 8.04 (s, 1H, H _TrCH ), 5.39-5.29 (m, 2H, H ₂ , H ₃ ), 5.28-5.17 (m, 2H, H ₁ , H ₄ ), 4.79-4.70 (m, 2H, H ₈ ), 4.68 (s, 2H, H ₁₀ ), 4.33 (s, 2H, H ₉ ), 4.29-4.16 (m, 2H, H _6a , H _7a ), 4.14-3.99 (m, 2H, H _6b , H _7b ), 3.76- 3.71 (m, 2H, H15), 3.70-3.62 (m, 11H, H5, H11-H14, H16), 2.15 (s, 3H, OAc), 2.03 (s, 3H, OAc), 1.88 (s, 3H, OAc), 1.43 (s, 9H, H _tBu ). Synthesis of compound 127: Compound 126 (500 mg, 0.65 mmol, 1 eq) was dissolved in dry DMF (3.25 mL), then NaN3 (213.2 mg, 3.28 mmol, 5 eq) was added, and the reaction stirred at 55 °C for 5 days. Upon completion ( ¹ H-NMR monitoring), the mixture was concentrated in vacuo and the crude product purified via automated flash chromatography (CH ₂ Cl ₂ with MeOH gradient from 3% to 10%) to obtain pure product 127 as a white foam (430 mg, 86%). 1H-NMR (400MHz, CD3OD): δ(ppm)= 8.09 (s, 1H, HTrCH’), 8.04 (s, 1H, H _TrCH ), 5.39-5.29 (m, 2H, H ₂ , H ₃ ), 5.28-5.17 (m, 2H, H ₁ , H ₄ ), 4.79-4.70 (m, 2H, H ₈ ), 4.68 (s, 2H, H ₁₀ ), 4.33 (s, 2H, H ₉ ), 4.29-4.16 (m, 2H, H _6a , H _7a ), 4.14-3.99 (m, 2H, H _6b , H _7b ), 3.72 (m, 11H, H5, H11-H15), 3.40-3.61 (m, 2H, H16), 2.15 (s, 3H, OAc), 2.03 (s, 3H, OAc), 1.88 (s, 3H, OAc), 1.43 (s, 9H, HtBu). Synthesis of compound 128: To a solution of 127 (390 mg, 0.51 mmol) in dry MeOH (8.7 mL) a freshly prepared 0.1M NaOMe solution (1.5 mL) in dry MeOH was added to a 0.05M final concentration of the substrate (0.014M final concentration of NaOMe). The reaction was stirred at room temperature, under N ₂ for 1h. Upon completion (TLC monitoring CH ₂ Cl ₂ :MeOH 9:1, R _f :0.50) the reaction was neutralized with Amberlite® IR120 hydrogen form ion-exchange resin, filtered and concentrated in vacuo to obtain the pure product 128 (311.3 mg, 95%). 1H-NMR (400MHz, CD ₃ OD): δ(ppm)= 8.04 (s, 1H, H _TrCH’ ), 8.01 (s, 1H, H _TrCH ), 5.04 (s, 1H, H ₁ ), 4.99 (d, 1H, J _2-3 = 5.1 Hz, H2), 4.71-4.63 (m, 4H, H8, H10), 4.29 (s, 2H, H9), 4.21-4.13 (m, 1H, H7a), 4.05 (dd, 1H, J3-4 = 9.4 Hz, J3-2 = 5.1 Hz, H3), 3.98- 3.91 (m, 1H, H _7b ), 3.85-3.75 (m, 2H, H ₆ ), 3.70-3.62 (m, 11H, H ₄ , H ₁₁ -H ₁₅ ), 3.40-3.33 (m, 3H, H ₅ , H ₁₆ ), 1.44 (s, 9H, H _tBu ). MS (ESI): m/z calculated for [C ₂₅ H ₄₂ N ₁₀ NaO ₁₀ ] ⁺ : 665.30 [M + Na] ⁺ , found: 665.58 Synthesis of compound 129: Compound 128 (60 mg, 0.09 mmol, 1 eq.) was dissolved in a 9:1 mixture of dry CH2Cl2 and TFA (1.88 mL). The reaction was stirred at room temperature, under N ₂ for 2h. Upon completion (TLC monitoring, CHCl3:MeOH 8:2, Rf:0.1) the mixture was concentrated in vacuo and co-evaporated with toluene three- times to obtain the pure TFA salt 129 as a white foam (54.9 mg, 93%). Synthesis of compound 130: The TFA salt 129 (150 mg, 0.23 mmol, 1 eq.) was dissolved in H2O (1.9 mL) and diluted with 1,4-dioxane (9.6 mL), then 1,3-Di-Boc-2-(trifluoromethylsulfonyl)guanidine (107.3 mg, 0.27 mmol, 1.2 eq) was added. After five minutes, triethylamine (95 ^L, 0.69 mmol, 3 eq) was slowly added and the reaction stirred at RT overnight. Upon completion (TLC monitoring, CH2Cl2:MeOH 9:1, Rf=0.55) the mixture was diluted with AcOEt and washed with brine three-times. The organic phase was dried over Na ₂ SO ₄ , filtered and concentrated in vacuo. The crude was purified via automated flash chromatography (CH ₂ Cl ₂ with a MeOH gradient from 0% to 20%) to obtain the pure product 130 as a white foam (128.1 mg, 71%). 1H-NMR (400MHz, CD ₃ OD): δ(ppm)= 8.13 (s, 1H, H _TrCH ), 8.04 (brs, 1H, H _TrCH’ ), 5.06 (s, 1H, H ₁ ), 5.01 (dd, 1H, J _2-3 = 5.1 Hz, J _2-1 = 1.2 Hz, H ₂ ), 4.72-4.60 (m, 6H, H ₈ , H _10, H ₉ ), 4.22-4.13 (m, 1H, H7a), 4.06 (dd, 1H, J3-4 = 9.7 Hz, J3-2 = 5.1 Hz, H3), 3.98- 3.90 (m, 1H, H7b), 3.86-3.76 (m, 2H, H6), 3.70-3.60 (m, 11H, H ₄ , H ₁₁ -H ₁₅ ), 3.41-3.31 (m, 3H, H ₅ , H ₁₆ ), 1.52 (s, 9H, H _tBu ), 1.48 (s, 9H, H _tBu ) . ¹³ C-NMR (400MHz, CD ₃ OD): δ(ppm) = 164.4 (COOtBu), 157.4 (COOtBu), 153.9 (C ₁₇ ), 146.0 (C _Trq’ ), 144.8 (CTrq), 125.8 (CTrCH’), 124.8 (CTrCH), 99.2 (C1), 84.5 (CquattBu), 80.5 (CquattBu), 75.2 (C5), 71.6, 71.5, 71.4 (C12, C13, C14), 71.0 (C ₁₅ ), 70.8 (C ₁₁ ), 70.3 (C ₃ ), 67.7 (C ₄ ), 67.0 (C ₇ ), 65.2 (C ₂ ), 65.0 (C ₁₀ ), 62.2 (C ₆ ), 51.7 (C ₁₆ ), 51.0 (C ₈ ), 36.9 (C ₉ ), 28.6 (tBu), 28.2 (tBu). MS (ESI): m/z calculated for [C ₃₁ H ₅₃ N ₁₂ O ₁₂ ] ⁺ : 785.39 [M ⁺ H] ⁺ , found: 785.40; m/z calculated for [C31H52N12NaO12] ⁺ : 807.37 [M + Na] ⁺ , found: 807.44. Synthesis of dimeric compound 133: The dimeric compound 133 was synthesized according to the following reaction scheme:

Synthesis of compound 132: A 0.01 M CuSO4∙5H2O solution and a 0.04 M Na-ascorbate solution were prepared in deoxygenated water. A 0.04 M solution of 131 (prepared according to Ordanini et al. Chem Comm 2015, 51, 3816), a 0.03 M solution of Tris [(1-benzyl-1H-1,2, 3- triazol-4-yl) methyl] amine (TBTA) and a 0.2 M solution of 121 were prepared in deoxygenated THF. To the solution of 131 (600 µL, 24 µmol, 1 mol eq) were added, in sequence: 0.2 mol eq of the TBTA solution (146 µL, 4.4 µmol), 0.1 mol eq of the CuSO4∙5H2O solution (240 µL, 2.4 µmol) and 0.4 mol eq of the Na-ascorbate solution (240 µL, 9.6 µmol). The mixture was stirred at room temperature for 10 minutes, then 2.2 mol eq of the 121 solution (530 µL, 53 µmol) was added. The reaction was stirred under MW irradiation at 60°C. Upon completion (TLC monitoring H2O:CH3CN 1:1), the solvents were evaporated and the crude product was purified via size-exclusion chromatography on a Sephadex LH-20 column (Ø 3 cm, H 55 cm; eluent: MeOH) to obtain pure product 132 as a yellow foam (19 mg, 38%) 1H-NMR (400 MHz, CD3OD): δ(ppm)= 8.61 (s, 2H, HT1), 8.14 (s, 2H, HCHtr), 7.86 (s, 2H, HR2), 7.20 (s, 2H, HR5), 7.15 (s, 2H, H _R10 ), 5.09 (s, 2H, H ₁ ), 5.04 (d, 2H, J _2-3 = 5.1 Hz, H ₂ ), 4.79-4.67 (m, 4H, H ₈ ), 4.67-4.54 (s, 4H, H ₉ ), 4.34-4.30 (m, 4H, H _G9 ), 4.30-4.18 (m, 10H, H _G1 + H _G5 + H _7s ), 4.11 (dd, 2H, J _3-4 = 9.4 Hz, J3-2 = 5.3 Hz, H3), 4.06-3.99 (m, 2H, H7b), 3.98-3.90 (m, 12H, HG10 + HG2 + HG6), 3.81-3.65 (m, 30H, H4 + HG4 + HG8 + H _G12 + H _G3 + H _G7 + H _G11 + H ₆ ), 3.48-3.40 (m, 2H, H ₅ ), 1.50 (s, 18H, 6xCH ₃ ), 1.47 (s, 18H, 6xCH ₃ ). ¹³ C-NMR (400 MHz, CD ₃ OD): δ(ppm)= 155.3, 154.9 (C _R6 , C _R11 ), 154.1 (C ₁₀ ), 150.5 (C _R3 ), 126.9 (CTC5), 122.3 (CR1), 119.1 (CR10), 118.4 (CR5), 115.9, 114.5 (CR4, CR9), 113.0 (CR2), 99.2 (C1), 92.8, 91.7 (CR7, CR8), 84.6 (C _quat t _Bu ), 80.6 (C _quat t _Bu ), 75.3 (C ₅ ), 74.1, 73.7 (C _G3 , C _G7 , C _G11 ), 70.9 (C _G9 , C _G5 or C _G1 ), 70.8 (C _G2 , C _G6 ), 70.6 (C _G10 ), 70.3 (C ₃ ), 69.3 (C _G1 or C _G5 ), 67.7 (C ₄ ), 67.2 (C ₇ ), 65.3 (C ₂ ), 62.4, 62.3, 62.2, 62.1 (CG4, CG8, CG12, C6), 51.0 (C8), 37.0 (C9), 28.6 (tBu), 28.2 (tBu). MS (MALDI, matrix: DHB, solvent: MeOH): m/z calculated for [C ₈₉ H ₁₂₉ N ₁₈ O ₃₄ ] ⁺ : 1993.892 [M - 1Boc + H] ⁺ , found: 1994.935; m/z calculated for [C ₈₄ H ₁₂₁ N ₁₈ O ₃₂ ] ⁺ : 1893.839 [M - 2Boc + H] ⁺ , found: 1894.914; m/z calculated for [C79H113N18O30] ⁺ : 1793.839 [M - 3Boc + H] ⁺ , found: 1794.763; m/z calculated for [C ₇₄ H ₁₀₅ N ₁₈ O ₂₈ ] ⁺ : 1693.735 [M - 4Boc + H] ⁺ , found: 1694.096. Synthesis of compound 133: Compound 132 (11 mg, 5 μmol) was dissolved in a 9:1 mixture of anhydrous THF and TFA (900 ^L). The reaction was stirred at room temperature, under N ₂ for 1h. Upon completion ( ¹ H-NMR monitoring, CD ₃ OD), the mixture was concentrated in vacuo and co-evaporated with toluene three times. Crude product was purified via semi-preparative HPLC (conditions reported below) to obtain the pure product 133 (bis-formate salt) as a yellow foam (8.9 mg, 55%). HPLC: Flow: 10 mL/min; UV channels: 210 nm; 254 nm; A: H ₂ O + 0.1% HCO ₂ H, B: CH ₃ CN. Gradient: 0-5 min: 0% B, 5-20 min: 0 - 45% B; tr (133) = 16.29 min. 1H-NMR (400MHz, DMSO-d ⁶ ): δ(ppm)= 8.73 (brs, 2H, H ₁₀ ), 8.57 (s, 2H, H _TC5 ), 8.49 (brs, 2H, FA), 8.16 (s, 2H, H _TrCH ), 7.88- 7.75 (m, 8H, HR2, NH,NH2), 7.22 (s, 2H, HR5), 7.16 (s, 2H, HR10), 5.49 (brs, 2H, OH-3), 5.31 (brs, 2H, OH-4), 5.05 (s, 2H, H1), 4.94-4.85 (m, 4H, H ₂ , OH-6), 4.83-4.58 (m, 10H, H ₈ , OH-Peg), 4.38 (s, 4H, H ₉ ), 4.31-4.19 (m, 12H, H _G1 , H _G5 , H _G9 ), 4.12-4.04 (m, 2H, H _7a ), 4.00-3.80 (m, 16H, H _7b , H ₃ , H _G2 , H _G6 , H _G10 ), 3.71- 3.49 (m, 30H, H6, H4, HG4, HG8, HG12, HG3, HG7, HG11), 3.44-3.39 (m, 2H, H5). ¹³ C-NMR (400MHz, CD3OD): δ(ppm) extrapolated from HSQC = 156.9 (FA), 125.2 (C _TC5 ), 123.3 (C _TrCH ), 117.8 (C _R10 ), 117.5 (C _R5 ), 111.7 (C _R2 ), 97.5 (C ₁ ), 74.8 (C ₅ ), 73.2 (C _G4 , C _G8 , C _G12 , C _G3 , C _G7 , C _G11 ), 69.5 (C _G10 , C _G2. C _G6 ), 68.9 (C ₃ , C _G9 , C _G1 , C _G5 ), 66.5 (C4), 65.8 (C7), 64.0 (C2), 60.6 (C6), 49.9 (C8), 36.7 (C9). HRMS (ESI): m/z calculated for [C74H105N18O28] ⁺ : 1693.7346 [M + H] ⁺ , found: 1693.7382; m/z calculated for [C ₇₄ H ₁₀₄ N ₁₈ NaO ₂₈ ] ⁺ : 1715.7165 [M + Na] ⁺ , found: 1715.7208 (after deconvolution); m/z calculated for [C ₇₄ H ₁₀₆ N ₁₈ O ₂₈ ] ²⁺ : 847.3712 [M + 2H] ²⁺ , found: 847.3713; m/z calculated for [C74H105N18NaO28] ²⁺ : 858.3622 [M + Na + H] ²⁺ , found: 858.3618; m/z calculated for [C74H104N18Na2O28] ²⁺ : 869.3531 [M + 2Na] ²⁺ , found: 869.3525, m/z calculated for [C ₇₄ H ₁₀₆ N ₁₈ NaO ₂₈ ] ³⁺ : 572.5774 [M + 2H + Na] ³⁺ , found: 572.5781; m/z calculated for [C ₇₄ H ₁₅₆ N ₁₈ Na ₂ O ₂₈ ] ³⁺ :579.9047 [M + 2Na + H] ³⁺ , found: 579.9049; m/z calculated for [C74H104N18Na3O28] ³⁺ : 587.2320 [M + 3Na] ³⁺ , found: 587.2321. The dimeric compound 135 was synthesized according to the following reaction scheme:

Synthesis of compound 134: A 0.01 M CuSO4∙5H2O solution and a 0.04 M Na-ascorbate solution were prepared in deoxygenated water. A 0.04 M solution of 131 (prepared according to Ordanini et al. Chem Comm 2015, 51, 3816), a 0.03 M solution of Tris [(1-benzyl-1H-1,2, 3- triazol-4-yl) methyl] amine (TBTA) and a 0.2 M solution of 130 were prepared in deoxygenated THF. To the solution of 131 (1.17 mL, 47 µmol, 1 mol eq) were added, in sequence: 0.2 mol eq of the TBTA solution (313 µL, 9.4 µmol), 0.1 mol eq of the CuSO4∙5H2O solution (470 µL, 4.7 µmol) and 0.4 mol eq of the Na-ascorbate solution (475 µL, 19 µmol). The mixture was stirred at room temperature for 10 minutes, then 2.2 mol eq of the 130 solution (50 µL, 100 µmol) was added. The reaction was stirred under MW irradiation at 60°C. Upon completion (TLC monitoring H2O:CH3CN 1:1), the solvents were evaporated and the crude product was purified via size-exclusion chromatography on a Sephadex LH-20 column (Ø 3 cm, H 55 cm; eluent: MeOH) to obtain pure product 134 as a yellow foam (25.5 mg, 22%) 1H-NMR (400MHz, CD3OD): δ(ppm)= 8.59 (s, 2H, HTC5), 8.14 (s, 2H, H _TrCH ), 7.94 (s, 2H, H _TrCH’ ), 7.87 (s, 2H, H _R2 ), 7.24 (s, 2H, H _R5 ), 7.19 (s, 2H, H _R10 ), 5.03 (s, 2H, H ₁ ), 4.98 (d, 2H, J _{2- 3} = 5.2 Hz, H ₂ ), 4.70-4.52 (m, 16H, H ₈ , H ₁₆ , H ₉ , H ₁₀ ), 4.34 (t, 4H, JG9-G10 = 4.4 Hz, HG9), 4.30-4.24 (m, 8H, HG1, HG5), 4.16-4.12 (m, 2H, H7a), 4.04 (dd, 2H, J3-4 = 9.5 Hz, J3-2 = 5.2 Hz, H3), 3.98-3.87 (m, 18H, H _G10 , H _G2, H _G6 , H _7b , H ₁₅ ), 3.81-3.54 (m, 46H, H _4, H _G4, H _G8 , H _G12, H _G3, H _G7, H _G11, H ₆ , H ₁₁ , H ₁₂ , H ₁₃ , H ₁₄ ), 1.51 (s, 18H, Ht _Bu ), 1.48 (s, 18H, Ht _Bu ). HRMS (ESI): m/z calculated for [C112H167N24NaO42] ⁺ : 2520.1670 [M + H] ⁺ , found: 2520.1633; m/z calculated for [C112H166N24NaO42] ⁺ : 2542.1489 [M + Na] ⁺ , found: 2542.1438; m/z calculated for [C ₁₁₂ H ₁₆₅ N ₂₄ Na ₂ O ₄₂ ] ²⁺ : 2564.1309 [M + 2Na - H] ⁺ , found: 2564.1274 (after deconvolution). m/z calculated for [C ₁₁₂ H ₁₆₈ N ₂₄ O ₄₂ ] ²⁺ : 1260.5874 [M + 2H] ²⁺ , found: 1260.5823; m/z calculated for [C112H167N24NaO42] ²⁺ : 1271.5783 [M + Na + H] ²⁺ , found: 1271.5763; m/z calculated for [C ₁₁₂ H ₁₆₆ N ₂₄ Na ₂ O ₄₂ ] ²⁺ : 1282.5693 [M + 2Na] ²⁺ , found: 1282.5676; m/z calculated for [C ₁₁₂ H ₁₆₉ N ₂₄ O ₄₂ ] ³⁺ : 840.7275 [M + 3H] ³⁺ , found: 840.7244; m/z calculated for [C ₁₁₂ H ₁₆₈ N ₂₄ NaO ₄₂ ] ³⁺ : 848.0548 [M + Na + 2H] ³⁺ , found: 848.0525; m/z calculated for [C112H167N24Na2O42] ⁺ : 855.3821 [M + 2Na + H] ³⁺ , found: 855.3794; m/z calculated for [C ₁₁₂ H ₁₆₆ N ₂₄ Na ₃ O ₄₂ ] ³⁺ : 862.7095 [M + 3H] ³⁺ , found: 862.7066. Synthesis of compound 135: Compound 134 (14.5 mg, 5.7 μmol) was dissolved in a 9:1 mixture of anhydrous CH2Cl2 and TFA (570 ^L). The reaction was stirred at room temperature, under N ₂ for 1h. Upon completion ( ¹ H-NMR monitoring, CD ₃ OD), the mixture was concentrated in vacuo and co-evaporated with toluene three times. Crude product was purified via semi-preparative HPLC (conditions reported below) to obtain the pure product 135 as bis-formate salt (4.3 mg, 35%). HPLC: Flow: 10 mL/min; UV channels: 210 nm; 254 nm; A: H ₂ O + 0.1% HCO ₂ H, B: CH ₃ CN. Gradient: 0-2 min: 0% B, 2-27 min: 0 - 40% B; tr (135) = 22.04 min 1H-NMR (400MHz, DMSO-d ⁶ ): δ(ppm)= 8.57 (brs, 2H, H ₁₇ ), 8.50 (s, 2H, H _TC5 ), 8.44 (brs, 2H, FA), 8.14 (s, 2H, H _TrCH ), 8.09 (s, 2H, H _TrCH’ ), 7.86 (s, 2H, H _R2 ), 7.70 (brs, 6H, NH, NH ₂ ), 7.20 (s, 2H, HR5), 7.16 (s, 2H, HR10), 5.47 (brs, 2H, OH-3), 5.26 (brs, 2H, OH-4), 5.01 (s, 2H, H1), 4.87 (d, 2H, J2-3 = 4.8 Hz, H2), 4.73 (brs, 2H, OH-6), 4.68-4.55 (m, 14H, H ₈ , H ₁₆ , OH-Peg), 4.51 (s, 4H, H ₁₀ ), 4.39 (s, 4H, H ₉ ), 4.28-4.20 (m, 12H, H _G1 , H _G9 , H _G5 ), 4.05-3.98 (m, 2H, H _7a ), 3.91-3.80 (m, 20H, H _7b , H ₃ , H ₅ , H _G6, HG2,HG10), 3.61-3.48 (m, 40H, H6, H4, H11-H15, HG4, HG8, HG12, HG3, HG7, HG11). HRMS (ESI): m/z calculated for [C92H135N24O34] ⁺ : 2119.9573 [M + H] ⁺ , found: 2119.9578; m/z calculated for [C ₉₂ H ₁₃₄ N ₂₄ NaO ₃₄ ] ⁺ : 2141.9392 [M + H] ⁺ , found: 2141.9407; m/z calculated for [C ₉₂ H ₁₃₃ N ₂₄ Na ₂ O ₃₄ ] ⁺ : 2163.9211 [M + 2Na - H] ⁺ , found: 2163.9216 (after deconvolution); m/z calculated for [C92H136N24O34] ²⁺ : 1060.4825 [M + 2H] ²⁺ , found: 1060.4799; m/z calculated for [C ₉₂ H ₁₃₅ N ₂₄ NaO ₃₄ ] ²⁺ : 1071.4735 [M + Na + H] ²⁺ , found: 1071.4708; m/z calculated for [C ₉₂ H ₁₃₄ N ₂₄ Na ₂ O ₃₄ ] ²⁺ : 1082.4645 [M + 2Na] ²⁺ , found: 1082.4614; m/z calculated for [C92H137N24O34] ³⁺ : 707.3243 [M + 3H] ³⁺ , found: 707.3232; m/z calculated for [C92H136N24NaO34] ³⁺ : 714.6516 [M + 2H + Na] ³⁺ , found: 714.6503; m/z calculated for [C ₉₂ H ₁₃₅ N ₂₄ Na ₂ O ₃₄ ] ³⁺ : 721.9789 [M + 2Na + H] ³⁺ , found: 721.9775; m/z calculated for [C ₉₀ H ₁₃₀ N ₂₀ Na ₃ O ₃₄ ] ³⁺ : 729.3062 [M + 3Na] ³⁺ , found: 729.6389. Experimental analysis and results The inhibitory potency of the monovalent glycomimetic compounds of the invention towards the extra cellular domain (ECD) of the DC-SIGN and L-SIGN receptors was evaluated by competition experiments performed using Surface Plasmon Resonance (SPR) on Biacore T200 instrument at 25°C, using a CM4 sensorchip functionalized with SARS-CoV-2 Spike protein. The spike protein used was Spike HexaPro, described in Hsiesh et al. Science, 2020, 369, 1501. Its production and purification were performed as described for Spike 2P in Thépaut et al. PLOS Pathogens, 2021, 17, e1009576. Flow cells Fc1, Fc2 and Fc3 were activated with 60 µL of a mixture of EDC-NHS (according to manufacturer). Fc1 was functionalized with 16.7 µL of a solution of bovine serum albumin (BSA) at 20 µg/mL in 10 mM NaOAc at pH 4 and was used as a reference. Fc2 and Fc3 were functionalized with Spike HexaPro at 20 µg/mL in 10 mM NaOAc pH 5, reaching 1766 and 1913 RU respectively. The inhibitory potency of the compounds towards DC-SIGN and L-SIGN ECD was evaluated with competition tests performed with decreasing concentrations of the compounds from 5 mM to 9.7656 µM, using a 1:2 dilution. The compounds were co-injected with 20 µM DC-SIGN or 20 µM L-SIGN solutions. The flow was set at 5 µL/min in buffer A (25 mM Tris, 150 mM NaCl, 4 mM CaCl ₂ ) supplemented with 0.05% Tween20, with an association and dissociation time set to 100 seconds each. Surface regeneration was performed for 10 seconds at 100 µL/min with a stabilization period of 100 seconds, using 50 mM EDTA for DC-SIGN tests and 50 mM glycine NaOH pH 12, 0.15% Triton, 25 mM EDTA for L-SIGN tests. The results of the above competition experiments performed by SPR are illustrated in the graph of Figure 1, which shows the IC50 of compounds 106a, 113, 115, 119 (invention) compared with the IC ₅₀ of mannose and compound 103 (comparative examples). From the results reported in Figure 1 it can be seen that compounds 106a, 113, 115, 119 have a selectivity for L-SIGN up to 58 fold over DC-SIGN. Furthermore, compound 106a (IC50 24 μM) inhibits the L-SIGN receptor 80 times better than D- mannose (IC ₅₀ 1939 μM) and 11 times better than compound 103 (IC ₅₀ 278 μM).The most potent of the series, compound 119 (IC ₅₀ 18 μM) inhibits the L-SIGN receptor over two orders of magnitude better than D-mannose. The interaction of compound 106a with the L-SIGN receptor was also confirmed by Isothermal Titration Calorimetry (ITC) experiments (Figure 2). These experiments were carried out on a MicroCal PEAQ-ITC apparatus, at 25° C, in buffer A (25 mM Tris pH 8, 150 mM NaCl, 4 mM CaCl ₂ ). L-SIGN ECD (172 μM) was titrated with consecutive 2 μL injections of a 2 mM solution of compound 106a in Calcium buffer (30 μL of 20 mM compound 106a + 270 μL of Calcium buffer). The analysis was performed in triplicate and the graphs shown in Figure 2 (which report, respectively, Differential Power (DP) vs. time, and ^H vs. molar ratio) are representative of the average of the three experiments. The value of the dissociation constant obtained is: Kd = 12.8 ± 1.5 μM. This value confirms the high affinity of ligand 106a for the L-SIGN receptor. The results obtained from the ITC experiments for the ligand 106a, shown in Figure 2, confirm the excellent value (low micromolar) of the dissociation constant Kd and indicate that the interaction between ligand and L-SIGN receptor has an enthalpy contribution ( ^H) which is very favorable. The stoichiometry of interaction between ligand and L-SIGN receptor is 1,13 and the value of c (C-value) indicates that the concentration of L-SIGN receptor used in this experiment is appropriate for a correct analysis of the data. The inhibitory potency of the divalent glycomimetic compounds of the invention 133 and 135 towards the extra cellular domain (ECD) of the DC-SIGN and L-SIGN receptors was evaluated by direct interaction experiments performed using Surface Plasmon Resonance (SPR) on Biacore T200 instrument at 25°C, using a CM3 sensor chip S series. For this experiment the extracellular domain (ECD) of DC- SIGN and L-SIGN were immobilized onto the SPR surface in an oriented manner, by their N-terminus, taking advantage of biotine/streptavidin interaction. To generate DC/L SIGN specifically biotinylated at the N-terminus, 3 glycine residues at the N-terminus of the protein were added by site directed mutagenesis in order to allow a sortaging procedure. The biotinylated versions of DC/L-SIGN ECDs (Biot-ECDs) were prepared by sortaging as described in Achilli, S., Monteiro, J. T., Serna, S., Mayer-Lambertz, S., Thépaut, M., Le Roy, A., Ebel, C., Reichardt, N.-C., Lepenies, B., Fieschi, F., and Vivès, C. (2020) TETRALEC, Artificial Tetrameric Lectins: A Tool to Screen Ligand and Pathogen Interactions. IJMS 21, 1– 19 using a commercial synthetic biotinylated peptide, To generate the oriented SPR surfaces, the flow cells were functionalized with Streptavidin in 10 mM Acetate buffer pH 4 and the remaining activated groups were blocked with 1 M ethanolamine pH 8. After blocking, the flow cells were treated with 100 μL of 10 mM HCl to remove non-specifically bound proteins and 100 μL of 50 mM NaOH/ 1M NaCl to expose surface to regeneration protocol. Priming of the surface was done using the running buffer (25 mM Tris pH 8, 150 mM NaCl, 4 mM CaCl2, 0.05% Tween). A Streptavidin flow cell surface was used as reference (On Flow Cell 1 of a Biacore T200 with a level of functionalization of 1300 RU) for correction of the binding response. DC-SIGN–Biot-ECD and L-SIGN-Biot_ECD (solubilized in the same running buffer) are injected and captured on FC-2 and FC3 surfaces. When the desired density is reached, injection is stopped. An injection of 12s at 100 µL/min of 1M NaCl/10mM NaOH was done to eliminate non-specifically captured proteins. For DC-SIGN-Biot_ECD 1547 RU were captured on FC2 and for L- SIGN 1774 RU. Surfaces are ready for interaction. Regeneration of the surfaces was achieved by 50 mM glycine NaOH pH120.15% Triton 25 mM EDTA. Interaction studies and Kd determination were performed by injecting increasing concentrations of the ligands (here 133 and 135) ranging from 2 nM to 500 nM obtained by serial dilution in the running buffer. Binding curves were analyzed using Biacore T200 Evaluation Software 3.2.1 (GE Healthcare) and data were fit using Steady State Affinity model. The results of the above direct interaction experiments performed by SPR are illustrated in the graph of Figure 3, which shows the log of the apparent Kd (log Kd, nM) of compounds 133 and 135 (invention) for DC-SIGN and L-SIGN. The data show that these compounds reach nM affinities for L-SIGN (133, Kd 52 nM; 135, Kd 25 nM) and their selectivity over DC-SIGN is 200 fold (133) and 1000-fold (135), respectively. *** It is evident that those which have been described are only particular embodiments of the present invention. The person skilled in the art will be able to make to the invention all those modifications necessary for its adaptation to particular conditions, without however departing from the scope of protection as defined in the attached claims.