Styryl benzothiazolium salts and its uses against parasitic infections

Abstract

The present invention refers to benzothiazolium salts of formula (I) and its use in therapy. More particularly, they are useful in the treatment and / or prevention of parasitic infections. The present invention also relates to pharmaceutical composition comprising them.

Description

[0001] Styryl benzothiazolium salts and its uses against parasitic infections

[0002] The invention relates to novel compounds, which are styryl benzothiazolium salts, and its use in therapy; particularly they have shown antitrypanosomal and leishmanicidal activity.

[0003] Therefore, the present invention belongs to the field of medicine and veterinary science.

[0004] BACKGROUND ART

[0005] Trypanosomiasis and Leishmaniasis are considered neglected tropical diseases that affect humans and other animals. They are caused by infections of Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. Specifically, these parasites cause human African trypanosomiasis or sleeping sickness, American trypanosomiasis or Chagas disease and leishmaniasis (in its different clinical manifestations: visceral, cutaneous and mucocutaneous), respectively. These protozoa have life cycles that alternate between two different hosts, an insect vector and the mammalian host. In the insect, the procyclic (T. brucei), epimastigote (T. cruzi) and promastigote (Leishmania) forms are extracellular, whereas, in the mammalian host, the amastigotes forms of Leishmania spp. and T. cruzi progress intracellularly, except for the T. brucei parasites which are extracellular. The actual treatments against these diseases consist of drugs that are toxic, outdated and non-efficient for patients suffering these diseases.

[0006] The benzothiazole core has been recognized as an important scaffold with a wide range of pharmacological properties including anticancer, anti-inflammatory, antidiabetic, anticonvulsant, antioxidant, antiviral, and antimicrobial activity (Yadav et al., Intelligent Pharmacy 2023, 1, 122-132).

[0007] In document Velásquez-Torres et al., Pharmaceuticals 2023, 16, 896, a derivative of benzothiazole as a potential anti-amoebic agent against Entamoeba Histolytica is reported.

[0008] In document Cuevas-Hernández et al., Antimicrob Agents Chemother 2020, 64, e01742-19, a fluorinated phenylbenzothiazole arrests the Trypanosoma Cruzi cell cycle and diminishes the Infection of mammalian host cells is reported. In document Martínez-Cerón, et al., Parasitol Res 2021, 120, 2905–2918, phenylbenzothiazole derivatives show effects against a Trypanosoma Cruzi Infection.

[0009] In document, Dunn, et al., J. Med. Chem. 1966, 9, 751-753, 2-(nitro-heterocyclic) benzothiazoles were shown to be potent inhibitors of Trichomonas foetus in vitro, and several compounds also had anthelmintic activity in a natural mouse pinworm infection.

[0010] In document, Haugwitz, et al., J. Med. Chem. 1982, 25, 969-974, 2-heteroaromatic-substituted isothiocyanatobenzoxazoles and -benzothiazoles were reported to show anthelmintic activities.

[0011] In document, Lapierre et al., Chem Biol Drug Des. 2024; 103: e14525, 2-amido-benzothiazole derivatives showed relevant efficiency against Trypanosoma brucei and Leishmania infantum parasites together with low cytotoxicity against THP-1 macrophages.

[0012] In document, Chabrecek et al., Chemical Papers (1987), 41(5), 655-69, 2-styrylbenzothiazolium salts substituted at position 3 with antibacterial and antifungal activity were reported.

[0013] In document, CN109912532, 2-styrylbenzothiazolium salts and its application in preparing bacterial biomembrane inhibitors were reported.

[0014] In document, Eibergen, et al., ChemBioChem (2012), 13(4), 574-583, the identification of a benzothiazolium salt, ABTZ-1, and derivatives that displayed potent antibacterial activity against Gram-positive pathogens was reported.

[0015] In document, Sigmundova et al., ARKIVOC (2008), (8), 183-192, new 2-styryl benzothiazolium salts substituted on the heterocyclic ring with antimicrobial activity were described.

[0016] In document, Radovan et al., Collection of Czechoslovak Chemical Communications (2002), 67(12), 1820-1832, a series of new push-pull 2-(ω-phenylalkenyl) benzothiazolium compounds with methyl groups in different positions of the conjugated alkenyl bridge and antimicrobial activity were reported.

[0017] In document, Magdolen, et al., Conference of Organic Chemists on Advances in Organic Chemistry, 22nd, Casta-Papiernicka, Slovakia, June 11-13, 1997, 185, a family of 2-styrylbenzothiazolium salts with activity against Mycobacterium tuberculosis was described.

[0018] In document, Kovalenko, F. P. 1978, 15 pp, a family of 39 2-styrylbenzothiazolium salts with anthelmintic activity against Alveococcus multilocularis and Echinococcus granulosus was reported.

[0019] In document, Kortisova, et al., J. Chemical Papers (2006), 60(1), 52-55, compounds based on 2-ethynylbenzothiazolium salts with a furane unit exhibited significant activities against several bacterial, yeast, and mould strains. The effect on growth and on the plastid system of the unicellular flagellate Euglena gracilis was also studied.

[0020] In document Jian-Feng Ge, et al. Med. Chem. Commun., 2012, 3, 1435-1442, the synthesis of cyanine dyes and investigation of their in vitro antiprotozoal activities was described, specifically against Plasmodium falciparum K1, Trypanosoma cruzi, T. brucei rhodesiense and Leishmania donovani. Among them, trimethine cyanines containing benzothiazolyl groups exhibited strong activities against P. falciparum and T. cruzi, whilst one symmetric pentamethine cyanine containing a fluorinated benzothiazolyl group was highly active against T. b. rhodesiense.

[0021] Currently there is no effective prophylactic method to prevent diseases caused by these parasites and chemotherapeutic treatments do not have the desired effectiveness, are toxic and / or are threatened by the appearance of therapeutic failure and resistance. New drugs are therefore urgently needed.

[0022] Despite continued attempts to control and treat leishmaniasis, the emergence of drugresistant strains presents a serious problem that weakens the effectiveness of current treatment strategies. The drugs available to treat leishmaniasis are mainly pentavalent antimonials, the first line of treatment despite their toxicity and low effectiveness due to the easy appearance of resistance, amphotericin B, which requires parenteral administration, is too expensive in its liposomal form, the only one that is not very toxic, and is threatened by resistance and miltefosine, the only oral drug to treat the disease but which is not effective against all species of leishmania, is teratogenic, too expensive and cases of resulting resistance have already appeared. Of its long half-life (7 days) which causes the existence of subtherapeutic doses over time.

[0023] In the case of patients suffering Chagas only two drugs are approved, the first-line drug Benznidazole and the second-line drug Nifurtimox. They are effective in the acute phase of the disease and in congenital transmission. The administration is also recommended in the chronic phase, although the cure rate importantly decreases. At the same time, both of them cause serious side effects due to their high toxicity what leads to frequent treatment abandonment by the patients.

[0024] In view of the prior art, there is a need to provide improved antiparasitic agents. In particular, there is a need to provide further benzothiazole derivatives, which have improved antitrypanosomal effects.

[0025] SUMMARY OF THE INVENTION

[0026] The present invention discloses novel compounds, which are benzothiazolium salts modified with a styryl group at position 2 that incorporate an amino group at position 4 of the phenyl ring. The invention also concerns pharmaceutical compositions comprising the novel compounds and their use in therapy.

[0027] A first aspect of the present invention relates to a compound of general formula (I), or a pharmaceutically acceptable salt thereof:

[0028]

[0029] wherein R1 and R2 are each independently selected from H, halogen, -O-(Ci-C4)-alkyl or Ci-04 alkyl,

[0030] R3 and R4 are each independently selected from:

[0031] optionally substituted Ci-Cs alkyl and phenyl,

[0032] R3 and R4 form a five- or six-membered ring with the N to which they are bonded and with the phenyl ring that is bonded to that N, and

[0033] R3 and R4 form, together with the N to which they are bonded, a five- or sixmembered aliphatic or aromatic ring,

[0034] Rs is an optionally substituted C1-8 alkyl,

[0035] Re is a H, halogen or a optionally substituted C1-8 alkyl,

[0036] Z is a counterion to offset the positive charge of the nitrogen of the aromatic ring being zero the final charge of the compound of formula (I),

[0037] for use in the treatment and / or prevention of parasitic infections.

[0038] In one embodiment, R1 and R2 are each independently H or halogen, more preferably the halogen is chlorine or fluorine, and even more preferably the halogen is fluorine.

[0039] In another embodiment, R3 and R4 are each independently Ci-Cs alkyl, more preferably C1-C4 alkyl, and even more preferably ethyl or methyl.

[0040] In a preferred embodiment, R3 and R4 are each independently optionally substituted phenyl (Ph). If substituted, the substituents of the Ph groups are selected preferably from: C1-C4 alkyl, methoxy, halogen, amino (-NH2), nitro (-NO2) or combinations thereof. Preferably, the Ph group is unsubstituted.

[0041] In another embodiment, Rs is independently Ci-Cs alkyl, more preferably C1-C4 alkyl, and even more preferably propyl, ethyl or methyl.

[0042] In another embodiment, R6is independently H, halogen or Ci-Cs alkyl and more preferably is a H or F.

[0043] In another embodiment, R6is in position orto with respect to the -NR3R4 group. In a preferred embodiment, Z' is selected from: halide, acetate, besilate, benzoate, carbonate, bicarbonate, benzenesulphonate, bitartrate, citrate, estearate, phosphate, fumarate, glucuronate, glycolate, hexanoate, hydroxynaphtoate, lactate, mesylate, nitrate, nitrite, octanoate, oleate, pamoate, pantotenate, propionate, poligalacturonate, salicilate, succinate, sulphate, tartrate, teoclate, tosylate, triflate, tetraphenylborate y trifluoroacetate. More preferably, Z' is a halide (F’, Cl', Br or I'), even more preferably, Z' is I'.

[0044] In another embodiment, the preferred compounds of formula (I) for use are selected from the group:

[0045]

[0046] In a preferred embodiment, the parasitic infection is selected from: african trypanosomiasis, chagas, leishmaniasis, blastocystosis, cryptosporidiosis, amoebiasis, giardiasis, sarcosystosis, toxoplasmosis, trichomoniasis and malaria. More preferably, the parasitic infection is selected from african trypanosomiasis, chagas, leishmaniasis and malaria.

[0047] In another preferred embodiment, the infection is leishmaniasis caused by Leishmania major, Leishmania donovani or Leishmania infantum parasites.

[0048] A second aspect of the invention refers to a compound of formula (I) described above, wherein the compound is selected from the next ones:

[0049]

[0050] Another aspect of the invention relates to the compound of formula (I), or to a pharmaceutically acceptable salt thereof, as defined in the second aspect of the invention, for use as a medicament. In another aspect, the present invention relates to a pharmaceutical composition comprising at least one compound of formula (I) or a pharmaceutically acceptable salt thereof, as defined in the second aspect of the invention, together with pharmaceutically acceptable excipients, adjuvants and / or carriers, for the administration to a patient.

[0051] The pharmaceutically acceptable adjuvants and vehicles that may be used in said compositions are the adjuvants and vehicles known to those skilled in the art and are usually used to prepare therapeutic compositions.

[0052] The compounds described in the present invention, the salts thereof, as well as the pharmaceutical compositions containing them can be used together with other additional drugs, or active ingredients, in order to provide a combination therapy. Said additional drugs can make up part of the same pharmaceutical composition or, alternatively, they can be provided in the form of a separate composition for the administration thereof which is simultaneous or not to that of the pharmaceutical composition comprising a compound of formula (I), or a salt thereof.

[0053] In a particular embodiment, the pharmaceutical composition is prepared in a solid form or aqueous suspension, in a pharmaceutically acceptable diluent. The therapeutic composition provided by this invention can be administered by any suitable route of administration, for which said composition will be formulated in the pharmaceutical form suitable for the chosen route of administration. In a particular embodiment, the administration of the therapeutic composition provided by this invention is performed by the following routes: oral, topical, rectal or parenteral (including subcutaneous, intraperitoneal, intradermal, intramuscular, intravenous, etc.).

[0054] In a preferred embodiment of the present invention, the pharmaceutical compositions are suitable for oral administration, in solid or liquid form. The possible forms for oral administration are tablets, capsules, syrups or solutions and may contain conventional excipients known in the pharmaceutical field, such as aggregating agents (e.g., syrup, acacia, gelatine, sorbitol, tragacanth or polyvinylpyrrolidone), fillers (e.g., lactose, sugar, corn starch, calcium phosphate, sorbitol or glycine), disintegrants (e.g., starch, polyvinylpyrrolidone or microcrystalline cellulose) or a pharmaceutically acceptable surfactant such as sodium lauryl sulphate.

[0055] The compositions for oral administration can be prepared by conventional galenic pharmacy methods, such as mixing and dispersing. The tablets can be coated following methods known in the pharmaceutical industry.

[0056] The pharmaceutical compositions can be adapted for parenteral administration, as sterile solutions, suspensions, or lyophilised solutions of the products of the invention, using the suitable dose. Suitable excipients can be used, such as pH buffering agents or surfactants.

[0057] The aforementioned formulations can be prepared using conventional methods, such as those described in the Pharmacopoeias of different countries and in other reference texts.

[0058] The administered amount of a compound of the present invention will depend on the relative efficacy of the chosen compound, the severity of the disease to be treated and the weight of the subject. The term “subject” in the present invention includes both humans and non-human animals.

[0059] All the compounds described in the invention can be in crystalline form as free compounds or as solvates. In this sense, the term “solvate”, as used here, includes both pharmaceutically acceptable solvates, in other words, solvates of the compound of formula (I) which can be used in the preparation of a medicine, and pharmaceutically unacceptable solvates, which can be used in the preparation of pharmaceutically acceptable salts or solvates. The nature of the pharmaceutically acceptable solvate is not critical as long as it is pharmaceutically acceptable. In a particular embodiment, the solvate is a hydrate. The solvates can be obtained by conventional solvation methods known to those skilled in the art.

[0060] For the application thereof in therapy, the compounds of formula (I) of the present invention, the salts or solvates thereof, will be found, preferably, in a pharmaceutically acceptable or substantially pure form, in other words, having a pharmaceutically acceptable purity level excluding normal pharmaceutical additives such as diluents and carriers, and not including material considered toxic at normal dosage levels. The purity levels for the active ingredient are preferably greater than 50%, more preferably greater than 70%, and still more preferably greater than 90%. In a preferred embodiment, they are greater than 95% of the compound of formula (I) or the salts or solvates thereof.

[0061] Another aspect of the invention relates to a method of treating and / or preventing parasitic infections, said method comprising administering to a subject a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein R₁ to R₆ are as defined in the first aspect of the invention.

[0062] A last aspect of the present invention relates to the use of a compound of formula (I) or to a pharmaceutically acceptable salt thereof, wherein R₁ to R₆ are as defined in the first aspect of the invention for the preparation of a medicament for use in the treatment and / or prevention of parasitic infections.

[0063] Definitions

[0064] The term “alkyl”, in the present invention, refers to a saturated, linear or branched hydrocarbon chain, which bind to the rest of the molecule by a single bond. The number of carbons of the chain is indicated next to the word alkyl. Thus, for example, C1-C4 alkyl refers to a saturated, linear or branched hydrocarbon chain having between 1 to 4 carbon atoms. Examples of “alkyl” are: methyl, ethyl, n-propyl, / -propyl, n-butyl, tert-butyl, sec-butyl, etc. Alkyl groups may be optionally substituted by one or more substituents. Non limiting substituents are, for example, halogens, ciano and methoxy.

[0065] Preferably, the alkyl groups present in formula (I) are unsubstituted.

[0066] The term "halogen" refers to F, Cl, Br or I.

[0067] The term "excipients, adjuvants and / or carriers" relates to molecular entities or substances through which the active ingredient is administered. Such pharmaceutical excipients, adjuvants or carriers can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and similar oils, excipients, disintegrating agents, humectants or dilutes. Suitable pharmaceutical excipients and carriers are known for the skilled person in the art.

[0068] The term "pharmaceutically acceptable salts" relates to salts or solvates which, on being administered to the recipient, are capable of providing a compound such as that described herein. The preparation of salts and derivatives can be carried out by methods known in the state of the art. Preferably, "pharmaceutically acceptable" relates to molecular entities and compositions that are physiologically tolerable and do not typically produce an allergic reaction or a similar unfavourable reaction, such as gastric upset, dizziness and similar side effects, when administered to a human.

[0069] In the sense used in this description, the expression “therapeutically effective amount” refers to the amount of the agent or compound capable of developing the therapeutic action determined by the pharmacological properties thereof, calculated to produce the desired effect and, in general, it will be determined, among other causes, by the very features of the compounds, including the age, state of the subject, the severity of the illness or disorder, and the route and frequency of administration.

[0070] The term "treatment or prevention" as used herein, unless otherwise indicated, relates to reversing, alleviating and inhibiting the progress of, or preventing the disorder or condition to which it applies in such terms, one or more symptoms of such disorder or condition.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. Methods and materials similar or equivalent to those described herein can be used in the practice of the present invention. Throughout the description and claims the word "comprise" and its variations are not intended to exclude other technical features, additives, components, or steps. Additional objects, advantages and features of the invention will become apparent to those skilled in the art upon examination of the description or may be learned by practice of the invention. The following examples are provided by way of illustration and are not intended to be limiting of the present invention. EXAMPLES

[0072] Example 1. Synthesis of styryl benzothiazolium salts

[0073] For the synthesis of the benzothiazolium precursors: To a solution of commercial 2-methyl benzothiazole (3 mmol) in acetonitrile (5 mL) was added methyl, ethyl or n-propyl iodide (18 mmol). The solution was stirred and heated at reflux (80 °C) for 6-96 h. The precipitate was filtered and washed with cold acetonitrile to give the pure product.

[0074] As an example, the synthesis of 2,3-dimethylbenzo[d]thiazol-3-ium iodide

[0075]

[0076] Table 1. Commercial benzothiazoles and alkyl iodides for the synthesis of the benzothiazolium precursors.

[0077]

[0078]

[0079] For the synthesis of the compounds 1-23: A solution of (hetero)aromatic aldehyde (0.3 mmol) and benzothiazolium precursor (0.3 mmol) in ethanol (5 mL) was heated 5 at reflux (80 °C) for 9-38 h. After this time, the precipitate was filtered and washed with cold ethanol and diethyl ether to give the pure product.

[0080] As an example, the synthesis of (E)-2-(4-(Dimethylamino)styryl)-3- methylbenzo[d]thiazol-3-ium iodide (compound 1).

[0081] 0

[0082]

[0083] Table 2. Commercial aldehyde reagents and benzothiazolium precursors for the synthesis of the compounds 1-23.

[0084]

[0085]

[0086]

[0087] Example 2. Characterization of the new benzothiazolium precursors and final compounds 1-23

[0088] NMR spectra were obtained on a Bruker Avance III 400 at an operating frequency of

[0089]

[0090] ,

[0091] Benzothiazolium

[0092]

[0093] methyl-3-propylbenzo[d]thiazol-3-ium iodide

[0094]

[0095] Off white solid (reaction time = 96 h, yield = 15%).1H NMR (400 MHz, DMSO-d₆): δ = 1.00 (3H, t, J = 7.2 Hz, N⁺CH₂CH₂CH₃), 1.81-1.90 (2H, sx, J = 7.6 Hz, N⁺CH₂CH₂CH₃). 3.20 (3H, s, CH₃), 4.62 (2H, t, J= 7.6 Hz, N⁺CH₂CH₂CH₃). 7.73 (1H, dt, J = 2.4 and 9.2 Hz, H-6), 8.41 (1 H, dd, J = 2.4 and 9.6 Hz, H-4), 8.47 (1 H, dd, J = 5.2 and 9.2 Hz, H-7) ppm.

[0096] 13C NMR (100.6 MHz, DMSO-d₆): δ = 10.71 (N⁺CH₂CH₂CH₃), 17.16 (CH3), 21.22 (N+CH2CH2CH3), 50.74 (N+CH2CH2CH3), 104.32 (d, J = 28.77 Hz, C4), 116.94 (d, J =

[0097]

[0098] ,,,,,,, and 8.0 Hz, H-6), 7.76 (1 H, d, J = 16 Hz, H-b), 7.81 (1 H, dt, J = 1.2 Hz and 8.4 Hz, H- 5), 7.90 (2H, d, 2H J= 8.8 Hz, H-3’ and H-5’), 8.09 (1H, d, J= 16 Hz, H-a), 8.17 (1H, d, J = 8.4 Hz, H-7), 8.36 (1 H, dd, J = 0.8 Hz and 8.0 Hz, H-4) ppm.

[0099] 13C NMR (100.6 MHz, DMSO-d₆): δ = 36.16 (N⁺CH₃), 110.07 (Cb), 116.47 (C7), 118.92 (C2’ and C6’), 124.03 (C4), 125.46 (C4”), 126.16 (C2”, C6” and 4’), 127.34

[0100]

[0101] ,, ,,,,,,,,, 7.66 (1 H, dt, J = 1.2 Hz and 7.6 Hz, H-5), 7.76 (1 H, dt, J = 1.2 Hz and 7.6 Hz, H-6), 7.82 (2H, d, J = 8.8 Hz, H-2’ and H-6’), 8.02 (1H, d, J = 15.2 Hz, H-b), 8.06 (1H, d, J = 8.4 Hz, H-4), 8.25 (1 H, dd, J = 0.8 Hz and 8 Hz, H-7) ppm.13C NMR (100.6 MHz, DMSO-d₆): δ = 12.49 (N(CH₂CH₃)₂), 35.47 (N+CH3), 44.15 (N(CH2-CH3)2), 105.64 (Ca), 111.60 (C3’ and C5’), 115.80 (C4), 121.01 (C1’), 123.72 (C7), 126.65 (C3a), 127.30 (C5), 128.78 (C6), 133.25 (C2’ And C6’), 141.91 (C7a), 150.03 (Cb), 151.42 (C4’), 171.15 (C2) ppm.

[0102]

[0103] Dark purple solid (reaction time = 9 h, yield = 85%).1H NMR (400 MHz, DMSO-cfe): 5 = 3.09 (6H, s, N(CH3)2), 4.16 (3H, s, N+CH3), 6.80 (2H, d, J = 9.2 Hz, H-3’ and H-5’), 7.55 (1H, d, J = 15.6 Hz, H-a), 7.71 (1H, dd, J= 2 and 8.8 Hz, H-6), 7.89 (2H, d, J = 9.2 Hz, H-2’ and H-6’), 8.05 (1 H, d, J = 15.2 Hz, H-b), 8.25 (1H, s, H-4), 8.27 (1H, d, J= 8.4 Hz, H-7) ppm.

[0104] 13C NMR (100.6 MHz, DMSO-d₆): δ = 35.69 (N⁺CH₃), 39.76 (N(CH3)2), 105.87 (Ca), 111.96 (C3’ and C5’), 115.82 (C4), 121.41 (CT), 125.16 (C7), 125.62 (C7a), 127.27

[0105]

[0106] ,,,,,,,, (1H, d, J = 15.2 Hz, H-b), 8.08 (1H, dd, J = 2.4 and 9.6 Hz, H-4), 8.30 (1H, dd, J = 5.2 and 8.8 Hz, H-7) ppm.13C NMR (100.6 MHz, DMSO-cfe): 6 = 12.54 (N(CH2CH3)2), 35.78 (N+CH3), 44.26 (N(CH2CH3)2), 103.54 (d, J = 28.17 Hz, C4), 105.51 (Ca), 111.72 (C3’ and C5’), 115.48 (d, J = 24.14 Hz, C6), 121.06 (C1’), 122.44 (C7a), 125.53 (d, J = 10.06 Hz, C7), 133.53 (C2’ and C6’), 143.31 (d, J= 13.08 Hz, C3a), 150.40 (Cb), 151.68 (C4’), 162.3 (d, J = 244.46 Hz, C5), 172.94 (C2) ppm.

[0107] HRMS (ESI) m / z: [M-I]+calcd for C20H22FN2S+341.1482, found 341.1495.

[0108] Compound 9. (E)-5-Chloro-2-(4-(diethylamino)styryl)-3-methylbenzo[c]thiazol-3-ium iodide

[0109]

[0110] Dark green solid (reaction time = 8 h, yield = 83%).1H NMR (400 MHz, DMSO-cfe): 5 = 1.15 (6H, t, J= 6.8 Hz, N(CH2CH3)2). 3.49 (4H, q, J =6.8 Hz, N(CH2CH3)2). 4.15 (3H, N+CH3), 6.80 (2H, d, J = 9.2 Hz, H-3’ and H-5’), 7.51 (1H, d, J = 15.2 Hz, H-a), 7.69 (1H, dd, J= 2 and 8.8 Hz, H-6), 7.87 (2H, d, J= 8.8 Hz, H-2’ and H-6’), 8.03 (1H, d, J = 15.2 Hz, H-b), 8.23 (1H, d, J = 2 Hz, H-4), 8.26 (1H, d, J= 8.8 Hz, H-7) ppm.

[0111] 13C NMR (100.6 MHz, DMSO-cfe): 5 = 12.52 (N(CH2CH3)2). 35.63 (N+CH3), 44.26 (N(CH2CH3)2). 105.31 (Ca), 111.72 (C3’ and C5’), 115.75 (C4), 121.07 (C1’), 125.11 (C7), 125.52 (C7a), 127.19 (C6), 133.61 (C2’ and C6’), 133.69 (C5), 143.03 (C3a), 150.73 (Cb), 151.73 (C4’), 172.29 (C2) ppm.

[0112] HRMS (ESI) m / z: [M-I]+calcd for C20H22ClN2S+357.1187, found 357.1191.

[0113] Compound 10. (E)-5-Bromo-2-(4-(diethylamino)styryl)-3-methylbenzo[c]thiazol-3-ium iodide

[0114]

[0115] Dark purple solid (reaction time = 9 h, yield = 78%).1H NMR (400 MHz, DMSO-cfe): 5 = 1.15 (6H, t, J = 6.8 Hz, N(CH2CH3)2). 3.50 (4H, q, J = 6.8 Hz, N(CH2CH3)2). 4.15 (3H, N+CH3), 6.82 (2H, d, J = 9.2 Hz, H-3’ and H-5’), 7.52 (1H, d, J = 15.2 Hz, H-a), 7.82 (1 H, dd, J = 2 and 8.8 Hz, H-6), 7.87 (2H, d, J = 9.2 Hz, H-2’ and H-6’), 8.05 (1 H, d, J= 15.2 Hz, H-b), 8.19 (1H, d, J= 8.4 Hz, H-7), 8.27 (1H, d, J= 1.6 Hz, H-4) ppm.

[0116] 13C NMR (100.6 MHz, DMSO-cfe): 5 = 12.55 (N(CH2CH3)2). 35.63 (N+CH3), 44.30 (N(CH2CH3)2), 105.30 (Ca), 111.76 (C3’ and C5’), 118.57 (C4), 121.11 (CT), 121.79

[0117]

[0118] methylbenzo[d]thiazol-3-ium iodide

[0119]

[0120] Purple solid (reaction time = 10 h, yield = 52%).1H NMR (400 MHz, DMSO-cfe): 5 = 3.05 (6H, d, J = 2 Hz, N(CH3)2), 4.26 (3H, s, N+CH3), 6.97 (1H, t, J = 9.2 Hz, H-5’), 7.69 (1 H, dd, J = 2 and 8.8 Hz, H-6’), 7.74 (1 H, dt, J = 2.8 and 9.2 Hz, H-5), 7.75 (1 H, d, J = 15.6 Hz, H-a), 7.95 (1H, dd, J= 2 and 16 Hz, H-2’), 8.09 (1H, d, J= 15.6 Hz, H-b), 8.20 (1H, dd, J = 4.4 and 9.6 Hz, H-4), 8.29 (1H, dd, J = 2.4 and 8.4 Hz, H-7) ppm.

[0121] 13C NMR (100.6 MHz, DMSO-cfe): 5 = 36.33 (N+CH3), 41.94 (d, J = 6.04 Hz, N(CH3)2), 109.74 (Ca), 110.69 (d, J= 28. 77 Hz, C7), 116.52 (d, J= 15.09 Hz, C2’), 116.65 (d, J = 2.41 Hz, C5’), 117.50 (d, J = 25.25 Hz, C5), 118.25 (d, J = 9.66 Hz, C4), 124.25 (d, J = 8.05 Hz, C1’), 128.93 (d, J = 13.08 Hz, C7a), 129.20 (C6’), 138.87 (C3a), 143.43 (d, J = 2.01 Hz, C4’), 148.43 (d, J = 2.01 Hz, Cb), 151.97 (d, J = 243.45 Hz, C3’), 160.72 (d, J = 247.48 Hz, C6), 171.80 (C2) ppm.

[0122] HRMS (ESI) m / z: [M-I]+calcd for C18H17N2F2S+331.1081, found 331.1135.

[0123] Compound 13. (E)-2-(4-(Dimethylamino)styryl)-6-fluoro-3-methylbenzo[d]thiazol-3-ium iodide

[0124]

[0125] Dark purple solid (reaction time = 10 h, yield = 83%).1H NMR (400 MHz, DMSO-cfe): 5 = 3.11 (6H, s, N(CH3)2), 4.20 (3H, s, N+CH3), 6.84 (2H, d, J = 9.2 Hz, H-3’ and H-5’), 7.58 (1H, d, J= 15.2 Hz, H-a), 7.69 (1H, dt, J = 2.4 and 8.8 Hz, H-5), 7.90 (2H, d, J = 9.2 Hz, H-2’ and H-6’), 8.05 (1H, d, J= 15.2 Hz, H-b), 8.12 (1H, dd, J = 4.4 and 9.2 Hz, H-4), 8.23 (1 H, dd, J = 2.8 and 8.4 Hz, H-7) ppm.

[0126] 13C NMR (100.6 MHz, DMSO-cfe): 5 = 35.85 (N+CH3), 39.71 (N(CH3)2), 106.19 (Ca), 110.50 (d, J = 28.17 Hz, C7), 111.92 (C3’ and C5’), 117.00 (d, J = 25.15 Hz, C5), 117.62 (d, J= 10.06 Hz, C4), 121.42 (C1’), 128.40 (d, J= 12.07 Hz, C7a), 132.86 (C2’ and C6’), 138.81 (d, J = 1.00 Hz, C3a), 150.31 (Cb), 153.51 (C4’), 160.46 (d, J = 246.47 Hz, C6), 171.52 (C2) ppm.

[0127] HRMS (ESI) m / z: [M-I]+calcd for C18H18N2FS+313.1175, found 313.1224.

[0128]

[0129] Dark purple solid (reaction time = 10 h, yield = 87%).1H NMR (400 MHz, DMSO-cfe): 5 = 1.16 (6H, t, J = 7.2 Hz, N(CH2CH3)2). 1.39 (3H, t, J = 7.2 Hz, N+CH2CH3), 3.51 (4H, q, J= 6.8 Hz, N(CH2CH3)2). 4.77 (3H, N+CH2CH3). 6.83 (2H, d, J = 9.2 Hz, H-3’ and H-5’), 7.54 (1H, d, J= 15.2 Hz, H-a), 7.57 (1H, dt, J= 2.4 and 9.2 Hz, H-6), 7.90 (2H, d, J= 9.2 Hz, H-2’ and H-6’), 8.07 (1H, d, J= 15.2 Hz, H-b), 8.14 (1H, dd, J= 2.4 and 9.6 Hz, H-4), 8.31 (1H, dd, J= 5.2 and 9.2 Hz, H-7) ppm.

[0130]

[0131] ,,,,,,, 150.92 (Cb), 153.73 (C4’), 162.47 (d, J = 245.46 Hz, C5), 172.98 (C2) ppm.

[0132] HRMS (ESI) m / z: [M-I]+calcd for C20H22FN2S+341.1482, found 341.1481.

[0133]

[0134] ,,, ,, 7.6 Hz, N(CH2CH2CH2CH3)2), 4.20 (3H, s, N+CH3), 6.79 (2H, d, J= 8.8 Hz, H-3’ and H-5’), 7.56 (1H, d, J= 15.2 Hz, H-a), 7.66 (1H, dt, J= 1.2 and 7.6 Hz, H-5), 7.76 (1H, dt, J = 1.2 and 7.6 Hz, H-6), 7.86 (2H, d, J = 8.8 Hz, H-2’ and H-6’), 8.02 (1H, d, J = 15.2 Hz, H-b), 8.06 (1H, d, J= 8 Hz, H-4), 8.27 (1H, dd, J= 0.8 and 8 Hz, H-7) ppm.

[0135] 13C NMR (100.6 MHz, DMSO-cfe): 5 = 13.81 (N(CH2CH2CH2CH3)2), 19.54

[0136]

[0137] 3-ium iodide

[0138]

[0139] , ,,,, 109.98 (Ca), 116.31 (d, J= 25.15 Hz, C6), 118.85 (C3’ and C5’), 123.23 (C7a), 125.55 (C4” x 2), 125.98 (d, J = 9.96 Hz, C7), 126.05 (CT), 126.22 ((C2” and C6”) x 2), 130.03 ((C3” and C5”) x 2), 131.99 (C2’ and C6’), 143.27 (d, J = 12.07 Hz, C3a), 145.41 (C1” x 2), 148.94 (Cb), 151.52 (C4’), 162.42 (d, J = 245.46 Hz, C5), 173.65 (C2) ppm.

[0140] HRMS (ESI) m / z: [M-I]+calcd for C28H22FN2S+437.1482, found 437.1493.

[0141]

[0142] Pink solid (reaction time = 38 h, yield = 10%).1H NMR (400 MHz, DMSO-cfe): 6 = 2.41 (3H, s, Ar-CH3), 2.45 (3H, s, Ar-CH3), 4.23 (3H, s, N+CH3), 6.90 (2H, d, J = 8.8 Hz, H-3’ and H-5’), 7.18 (4H, d, J = 7.2 Hz, (H-2”and H-6”) x 2), 7.22 (2H, t, J = 7.2 Hz, H-4” x 2), 7.42 (4H, t, J = 7.2 Hz, (H-3” and H-5”) x 2), 7.72 (1 H, d, J = 16 Hz, H-a), 7.86 (2H, d, J= 8.8 Hz, H-2’ and H-6’), 7.99 (1H, s, H-4), 8.04 (1H, d, J= 15.6 Hz, H-b), 8.09 (1H, s, H-7) ppm.

[0143] HRMS (ESI) m / z: [M-l ]+calcd for C3oH27N2S+447.1889, found 447.1904.

[0144]

[0145] Cell culture Cell culture media were purchased from Gibco (Grand Island NY, USA). Fetal bovine serum (FBS) was a product of Harlan-Seralab (Belton, U. K.). Supplements and other chemicals not listed in this section were obtained from Sigma Chemicals Co. (St. Louis, Mo., USA). Plastics for cell culture were supplied by Thermo Scientific™ BioLite. All tested compounds were dissolved in DMSO at a concentration of 10 mg / mL and stored at-20°C until use. Cell lines were maintained in Dulbecco’s modified Eagle’s medium (DMEM) containing glucose (1 g / L), glutamine (2 mM), penicillin (50 lU / mL), streptomycin (50 pg / mL) and amphotericin (1.25 pg / mL), supplemented with 10% FBS.

[0146] THP1 cells (human monocytic cell line) were maintained in RPMI-1640 medium supplemented with 10% heat-inactivated fetal bovine serum (hiFBS) and 5% penicillin / streptomycin (37 °C, 5% CO2, and 100% humidity).

[0147] Parasite culture L. major promastigotes (LucRE9) were cultured at 28 °C in 5% CO2in modified RPMI-1640 medium (Invitrogen, Carlsbad, CA) with 10% hiFBS.

[0148] Cytotoxicity assays: The cytotoxic effect of the compounds was evaluated in MRC-5 cell line, through alamarBlue® assay (ThermoFisher scientific) (J. Med. Chem. 2018, 61, 1231-1240). The stock solutions of the compounds were prepared in DMSO, with the final DMSO concentration in each well maintained below 1%. Prior to compounds addition, 5 x 103cells per mL (MRC-5 cells) were seeded in 96-wells plates (100 pL / well) and incubated for 24h at 37 °C, 5% CO2to allow cell attachment. Subsequently, the compounds were added at various concentrations ranging from 0 to 100 pM, and the plates were incubated for 72 h. After the incubation period, 20 pL of resazurin solution (110 ng / ml) were added to each well and cells were incubated for 4 h. Then, cells were lysed with 50 pL / well of 3% SDS. The plate was incubated at 37 °C for an additional hour and subsequently, the fluorescence intensity was measure at the Infinite F200 plate reader (TECAN Austria, GmbH), exciting at 550 nm and recording the emission at 590 nm. The obtained results were expressed as the concentration of compound that reduces cell growth by 50% compared to untreated control cells (IC50). Data are presented as the average of at least three independent measurements, each conducted in triplicate conditions.

[0149] Cytotoxicity assays on THP1: Cytotoxicity on THP1 was measured through the alamarBlue® assay (Thermo Fisher Scientific). THP1 cells were seeded at a density of 3 x 105cells / mL in 96-well plates (100 pL / well) and treated with 20 ng / mL PMA (phorbol 12-myristate 13-acetate, Sigma) for 48 hours. Post-differentiation, the cells were washed and fresh medium was added (100 pL / well) before being reincubated. Following another 48 hours, the wells were washed again, and fresh medium with increasing concentrations of compounds was added (100 pL / well). Seventy-two hours later, 20 pL of resazurine solution (110 ng / mL) was added to each well, and the cells were incubated for an additional 4 hours at 37°C. Subsequently, 50 pL of 20% SDS was added to each well. The plate was incubated for an extra hour at 37°C before being analyzed for fluorescence using an Infinite F200 plate reader (TECAN Austria, GmbH). The excitation wavelength was set at 550 nm and the emission wavelength at 590 nm. Results are reported as the concentration of compounds that reduce cell growth by 50% compared to untreated control cells (IC50), determined using SigmaPlot with a four-parameter logistic curve. Data represent the average of three independent experiments, each conducted in triplicate.

[0150] In vitro antitrypanosomal activity against Trypanosoma brucei

[0151] Bloodstream forms (BSF) of T. brucei brucei 'single marker' S427 (S16) were grown at 37 °C, 5% CO2 in HMI-9 medium supplemented with 10% (heat-inactivated fetal bovine serum, hiFBS). Drug susceptibility assay was performed as described in Carvalho L et al., 2015 (Antimicrob Agents Chemother. 2015 Oct;59(10):6151-60). Briefly, parasites (1 x 104BSF per mL) were incubated in 96-well plates with increasing concentration of drugs / compounds for 72 h at 37 °C, 5% CO2 in culture medium. Cell proliferation was determined using the alamarBlue® assay (B. Raz, et al., Acta Trop 68 (1997) 139-147). The Alamar Blue assay is used to determine drug sensitivity of African trypanosomes (T. b. rhodesiense and T. b. gambiense) in vitro. Fluorescence was recorded with an Infinite® F200 microplate reader (Tecan Austria GmbH, Austria) equipped with 550 and 590 nm filters for excitation and emission wavelengths, respectively. The results are expressed as the concentration of compound that reduces cell growth by 50% compared to untreated control cells (IC50). Data were presented as the average of at least three independent measurements, each conducted in triplicate conditions.

[0152] In vitro antileishmanial activity against Leishmania ma / 'or promastigotes

[0153] The anti-leishmanial activity of the compounds was determined using MTT-based assay (Sigma-Aldrich) (Antimicrob Agents Chemother 2011, 55, 3838-3844). The stock solutions of the compounds were prepared in DMSO with a final DMSO percentage in each well maintained below 1%. 4 x 106parasites per mL were incubated at 28 °C in 96-well plates (50 pL / well) either alone or in the presence of increasing concentration of compounds DMSO for 72 h. After the incubation period, 10 pL of MTT (5 mg / ml) was added to each well and parasites were incubated for 4 h at 28°C. Subsequently, cell lysis was performed using 50 pL / well of 20% SDS. The plate was then incubated at 37 °C for an additional hour and then absorbance was measured at a wavelength of 540 using an Infinite F200 plate reader (TECAN Austria, GmbH). The IC50was calculated as described above. Data were presented as the average of at least three independent measurements, each conducted in triplicate conditions.

[0154] In vitro antileishmanial activity against Leishmania ma / 'or amastigotes

[0155] The antiparasitic activity of the compounds against the intracellular form of Leishmania major was evaluated using the Luciferase Assay System kit from Promega. THP1 cells were seeded at a density of 3 x 105cells / mL in 96-well plates (100 pL / well) and treated with 20 ng / mL PMA (phorbol 12-myristate 13-acetate, Sigma) for 48 hours to induce differentiation. Post-differentiation, the cells were washed and fresh medium was added (100 pL / well) before being reincubated. Following an additional 24 hours, the wells were washed, and 50 pL of L. major-LucRE9 parasites at a density of 1.5 x 106parasites / mL (suspended in RPMI-1640 medium 5% hiFBS and 5% penicillin / streptomycin) were added to the wells. The plates were then incubated at 35°C in 5% CO2. After 24 hours, the wells were washed three times with PBS, and fresh medium with increasing concentrations of compounds was added (100 pL / well). After another 72 hours of incubation, the cells were then treated with 25 pL of lysis buffer and stored at -80°C. Following 24 hours, 25 pL of luciferase enzyme substrate was added to each well, and the luciferase activity of the amastigotes was determined using a TECAN Infinite F200 microplate reader. Results are reported as the concentration of compounds that reduce parasite growth by 50% compared to untreated control infected macrophages (IC50), determined using SigmaPlot with a four-parameter logistic curve. Data represent the average of three independent experiments, each conducted in triplicate.

[0156] Antitrypanosomal and antileishmanial activity of prepared compounds on Trypanosoma brucei and on promastigotes of Leishmania major, respectively.

[0157] Table 3.

[0158] IC50 (uM) Selectivity Index (SI) Compd T. brucei L. major MRC-5 T.brucei L.major 1 0.000019 ± 0.0000053 0.02 ± 0.013 1.52 ± 0.37 79206.5 62.7 2 0.34 ± 0.13 0.02 ± 0.011 5.13 ± 0.76 15.1 252.0 3 0.00026 ±0.00017 0.0065 ± 0.0029 0.08 ± 0.03 294.5 12.0 4 0.00029 ±0.00019 0.007 ± 0.002 14.01 ± 1.71 48310 2001.4 5 0.00054 ± 0.00029 0.012 ± 0.03 45.47 ± 8.42 84203 3789.2 6 0.00067 ± 0.00001 0.0082 ± 0.0012 15.12 ± 1.27 22567 1843.9 7 0.00041 ± 0.00001 0.0065 ± 0.0010 0.0044 ± 0.0002 10.73 <1 8 0.036 ± 0.011 0.0083 ± 0.006 15.60 ±2.68 434 1879 9 0.0058 ± 0.001 0.0073 ± 0.004 14.65 ± 0.15 2547 2006 10 0.0066 ± 0.0017 0.034 ± 0.007 15.16 ± 0.58 2297 445 11 0.796 ± 0.133 0.162 ± 0.041 40.89 ± 3.52 51 252 12 0.989 ± 0.139 0.233 ± 0.109 57.44 ± 0.47 58 246 13 0.00092 ± 0.00004 0.010 ± 0.006 20.74 ± 0.93 22474 2074 14 0.191 ± 0.022 0.024 ± 0.003 21.93 ± 0.19 115 913 15 0.129 ± 0.061 0.0078 ± 0.0023 18.07 ± 1.70 140 2316 16 0.459 ± 0.095 0.048 ± 0.028 24.79 ±2.74 54 516 17 0.078 ± 0.008 0.013 ± 0.008 5.98 ± 0.14 76 460 18 0.011 ± 0.004 0.0096 ± 0.0039 7.76 ± 0.83 684 808 19 0.0051 ± 0.0002 0.044 ± 0.007 2.88 ± 0.31 564.7 65.5 20 0.91 ± 0.18 0.08 ± 0.02 4.21 ± 0.49 4.63 52.63 21 12.40 ±2.38 1.50 ± 0.03 12.87 ± 1.38 1.04 8.6 22 6.39 ± 0.25 2.77 ± 0.21 4.23 ± 0.11 <1 1.53 23 0.077 ± 0.013 0.029 ± 0.01 0.53 ± 0.11 6.88 18.3 The selectivity index (SI) was calculated related to a healthy cell line (MRC-5) as IC50 MRC-5 I IC50 T.brucei or IC50 MRC-51 IC50 L.major.

[0159] Antileishmanial activity of prepared compounds on amastigotes of Leishmania major.

[0160] Table 4.

[0161] IC50 (uM) Selectivity Index (SI) Compd L. major THP-1 MRC-5 THP-1 MRC-5 1 0.000485 ± 0.000617 22.4 ± 3.45 1.52 ± 0.37 46151 3132 2 0.0281 ± 0.00473 0.93 ± 0.02 5.13 ± 0.76 33 182 3 - - 0.08 ± 0.03

[0162] 4 0.000374 ± 0.000457 21.39 ± 1.65 14.01 ± 1.71 57146 37429 5 0.0911 ± 0.1239 29.96 ± 1.06 45.47 ± 8.42 329 499 6 0.0040 ± 0.0016 21.18 ± 0.91 15.12 ± 1.27 5267 3760 7 - - 0.0044 ± 0.0002

[0163] 8 0.00198 ± 0.00103 21.87 ± 0.3 15.60 ± 2.68 11101 7894 9 0.00130 ± 0.00178 6.7 ± 0.49 14.65 ± 0.15 5153 11261 10 0.00120 ± 0.00029 14.01 ± 6.17 15.16 ± 0.58 11620 12574 11 0.000463 ± 0.000363 67.18 ± 1.61 40.89 ± 3.52 145097 88315 12 0.0339 ± 0.0040 68.02 ± 1.48 57.44 ± 0.47 2001 1689 13 0.0043 ± 0.0004 20.72 ± 2.38 20.74 ± 0.93 4829 4834 14 0.0001216 ± 0.0000447 25.21 ± 4.22 21.93 ± 0.19 207319 180345 15 0.0000194 ± 0.0000171 19.99 ± 0.57 18.07 ± 1.70 1030412 931443 16 0.002437 ± 0.003798 52.14 ± 7.22 24.79 ± 2.74 21395 10172 17 0.01007 ± 0.0172 20.55 ± 0.07 5.98 ± 0.14 2040 594 18 0.0000343 ± 0.0000067 4.18 ± 0.82 7.76 ± 0.83 121866 226239 19 0.000664 ± 0.0001426 6.03 ± 0.45 2.88 ± 0.31 9075 4334 20 0.00392 ± 0.00548 0.89 ± 0.13 4.21 ± 0.49 227 1073 21 - - 12.87 ± 1.38

[0164] 22 - - 4.23 ± 0.11

[0165] 23 - - 0.53 ± 0.11

[0166] The selectivity index (SI) was calculated related to a healthy cell line (MRC-5) as IC50 THP-1 / IC50 L. major or IC50 MRC-5 / IC50 L.major.

Claims

CLAIMS1. Compound of formula (I), or a pharmaceutically acceptable salt thereof:whereinRi and R2are each independently selected from H, halogen, -O-(Ci-C4)-alkyl or Ci-C4 alkyl,R3and R4are each independently selected from:optionally substituted Ci-Cs alkyl and phenyl,R3and R4 form a five- or six-membered ring with the N to which they are bonded and with the phenyl ring that is bonded to that N, andR3 and R4 form, together with the N to which they are bonded, a five- or sixmembered aliphatic or aromatic ring,Rs is an optionally substituted C1-8 alkyl,Re is a H, halogen or an optionally substituted C1-8 alkyl,Z is a counterion to offset the positive charge of the nitrogen of the aromatic ring being zero the final charge of the compound of formula (I),for use in the treatment and / or prevention of parasitic infections.

2. Compound of formula (I) for use, according to claim 1, wherein R1 and R2are each independently H or halogen.

3. Compound of formula (I) for use, according to claim 2, wherein the halogen is chlorine or fluorine.

4. Compound of formula (I) for use, according to claim 1 or 2, wherein R3and R4are each independently Ci-Cs alkyl.

5. Compound of formula (I) for use, according to claim 4, wherein R3and R4 are each independently C1-C4 alkyl, preferably ethyl or methyl6. Compound of formula (I) for use, according to any of previous claims, wherein Rs is independently Ci-Cs alkyl, preferably C1-C4 alkyl, even more preferably propyl, ethyl or methyl.

7. Compound of formula (I) for use, according to any of previous claims, wherein Rs is independently H, halogen or Ci-Cs alkyl, preferably, Rs is H or F.

8. Compound of formula (I) for use, according to any of previous claims, wherein Rs is in position ortho with respect to the -NR3R4 group.

9. Compound of formula (I) for use, according to any of previous claims, Z- is selected from: halide, acetate, besylate, benzoate, carbonate, bicarbonate, benzenesulphonate, bitartrate, citrate, estearate, phosphate, fumarate, glucuronate, glycolate, hexanoate, hydroxynaphtoate, lactate, mesylate, nitrate, nitrite, octanoate, oleate, pamoate, pantotenate, propionate, polygalacturonate, salicylate, succinate, sulphate, tartrate, teoclate, tosylate, triflate, tetraphenylborate and trifluoroacetate.

10. Compound of formula (I) for use, according to any of previous claims, wherein the compound is selected from the group:

11. Compound of formula (I) for use, according to any of previous claims, wherein the parasitic infection is selected from: african trypanosomiasis, chagas, leishmaniasis, blastocystosis, cryptosporidiosis, amoebiasis, giardiasis, sarcosystosis, toxoplasmosis, trichomoniasis and malaria.

12. Compound of formula (I) for use, according to any of previous claims, wherein the the parasitic infection is Leishmaniasis caused by Leishmania major, Leishmania donovani or Leishmania infantum parasites.

13. Compound of formula (I) selected from:

14. Compound of formula (I), according to claim 13, for use as a medicament.

15. Pharmaceutical composition comprising at least one compound of formula (I) as defined in claim 13, or a pharmaceutically acceptable salt thereof, together with a pharmaceutically acceptable excipients, adjuvants and / or carriers.

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