Diazo compounds with Anti-trypanosomal activities

Abstract

The present invention provides diazo compounds having anti-trypanosomal activity, with less or no side-effects. The diazo compounds are structural analogue of quinapyramine and possess characteristics necessary for the targeted pharmacologic action of anti trypanosomosis, with reduced cytotoxicity. The compounds were found to have less cytotoxicity, and identical or better anti- parasitemia effect as compared to conventional quinapyramine sulfate.

Description

[0001] DIAZO COMPOUNDS WITH ANTI TRYPANOSOMAL ACTIVITIES FIELD OF THE INVENTION

[0002] The present invention relates to novel compounds having an anti-trypanosomal activity, and pharmaceutically acceptable salts thereof, and a method for preparing the same.

[0003] BACKGROUND OF THE INVENTION

[0004] Trypanosomosis is an economically important disease reported worldwide and is endemic in India causing high morbidity and mortality in a wide range of domestic animals. Trypanosoma evansi is the major causative agent and is pathogen to a wide variety of domestic and wild animals. The infection is mainly restricted to animals but the ability to infect human beings has also been reported due to lack of efficient apolipoprotein L 1. The parasite is mechanically transmitted by blood-sucking flies such as Tabanus and Stomoxys species. The disease has a major economic impact in tropical countries. The control of trypanosomosis may be aimed either at the fly or against the parasite. Due to difficulties in large scale fly control, trypanocides have been widely used to control the disease.

[0005] Trypanocidal drugs like Quinapyramine, Diminazene aceturate, Suramin, Isometamidium and Homidium (Figure 1) cause local and systemic reactions and sometimes death in cattle, horses, dogs, and pigs within minutes of treatment.

[0006] Sathaporn Jittapalapong et al. (2013) in Biomed Research International reported that quinapyramine belongs to the group of aminoquinaldine derivatives. Quinapyramine methyl- sulphate can be used to treat the infection by subcutaneous injection at a dose of 5 mg / kg bw. A more effective combination of quinapyramine sulphate and quinapyramine chloride (Triquin) can be used as a curative / preventive drug against T. evansi in horses and camels, administered by subcutaneous injection at a dose of 5-8 mg / kg bw. Local tolerance is sometimes low. However, the drug is quite efficient and the chemoprophylactic effect can last up to 4 months. In cattle, the use of quinapyramine is not recommended because it may induce crossresistance to both DA and IMC. Its use should be restricted to horses and camels only.

[0007] IN2560 / DEL / 2011 discloses a novel drug delivery system for quinapyramine sulphate in form of nano-particle formulation. The invention provides polymer based quinapyramine sulphate-loaded nano-particles.

[0008] Manuja et al, in Nanomedicine (Land), (2014) Aug;9(ll): 1625-34', in International Journal of Biological Macromolecules 88 (2016) 146-155', in Curr Top Med Chem. (2016);16(20):2316-27, in Current Topics in Medicinal Chemistry, Volume 16, Number 20 (2016), pp. 2231-2232 (2); in International Journal of Biological Macromolecules, Volume 92, (2016), Pages 788-794', in Nano-Structures & NanoObjects 16 (2018) 13-199', in Antimicrob Agents Chemother, (2018) Oct 24;62(ll):e00466-18', and in J Xenobiot (2023) Mar 2;13(1):148-158; have reported various research and have developed novel, effective safe nano delivery system for toxic trypanocidal drugs quinapyramine sulphate against Trypanosoma evansi.

[0009] Ruma Rani et al in Exp Parasitol (2020):219: 108018 reported nanotechnology enabled enhancement of anti-trypanosomal activity of piperine against Trypanosoma evansi.

[0010] Kedar S. Prayag et al in Journal of Drug Delivery Science and Technology Volume 81 (2023) 104215 reported preclinical evaluation of quinapyramine sulphate-loaded lipidic nanocarriers at a dose of 7.5mg / kg for trypanocidal effect against Trypanosoma evansi.

[0011] Although various efforts have been made to provide safe and effective delivery of compounds having anti-trypanosomal activities, there is need for more development in the field of biologically active molecules having safe, nontoxic and effective efficacy against Trypanosoma evansi.

[0012] OBJECT OF THE INVENTION

[0013] Accordingly, it is an object of the present invention to provide compounds having anti-trypanosomal activity, with less or no side-effects.

[0014] It is further an object of the present invention to provide compounds possessing essential structural characteristics necessary for the targeted pharmacological action of anti trypanosomosis.

[0015] It is another object of the present invention to provide novel compounds having diazo group and method for synthesis thereof.

[0016] It is another object of the present invention to provide structural analogue of quinapyramine having reduced cytotoxicity.

[0017] It is yet another object of the present invention to provide a pharmaceutical composition comprising the structural analogue of quinapyramine.

[0018] SUMMARY OF THE INVENTION

[0019] In an aspect of the present invention there is provided a compound having structural formula I as

[0020] R’-N=N-R I

[0021] where, R’ is amino substituted aromatic rings, and

[0022] R is a moiety represented by a structural formula A as

[0023]

[0024] It is also an aspect of the invention to provide a method for preparing compound of formula II, which comprising steps of:

[0025] i. mixing a first precursor in diluted HC1 on ice bath with constant stirring, ii. adding aqueous solution of sodium nitrite dropwise to the solution of step (i), under constant stirring at ice bath, followed by adding a second precursor to the solution, and

[0026] iii. obtaining precipitate of compound of formula (II),

[0027] where the first precursor and the second precursor are selected from aryl amine and quinapyramine sulphate vice versa, such that in the method the first precursor is different from the second precursor.

[0028] It is another aspect of the present invention to provide a structural analogue of quinapyramine having structure of formula II.

[0029] BRIEF DESCRIPTION OF THE FIGURES

[0030] Figure 1 illustrates Chemical structures of (a) Trivalent arsenics (b) Homidium (c) diminazene aceturate (d) Quinapyramine sulfate (e) Suramin (f) Isometamidium

[0031] Figure 2 illustrates different steps of synthesis of the compound IV.

[0032] Figure 3 illustrates Thin Layer Chromatography study to confirm completion of the reaction of Formula IV.

[0033] Figure 4 illustrates (a) NMR data of QS, (b) NMR data of Compound III, and (c) NMR data of Compound IV.

[0034] Figure 5 illustrates mass spectrum for (a) Compound III and (b) Compound IV.

[0035] Figure 6 illustrates FTIR spectrum of (a) Compound III and (b) Compound IV. Figure 7 illustrates UV absorption spectrum of (a) Compound III and (b) Compound IV.

[0036] Figure 8 illustrates cytotoxic analysis of (a) Compound III and (b) compound IV in different dosage on VERO cell lines.

[0037] Figure 9 illustrates in vivo anti-trypanosomal activity of quinapyramine sulfate and Compound III.

[0038] Figure 10 illustrates survival rate of T. evansi infected mice treated with quinapyramine sulfate and Compound III.

[0039] Figure 11 illustrates survival rate of T. evansi infected mice treated with quinapyramine sulfate and Compound IV.

[0040] DESCRIPTION OF THE INVENTION

[0041] The present invention is directed towards development of compounds having anti Trypanosoma activity, with reduced or no toxicity.

[0042] The present invention is described with reference to specific embodiments and the tables including the best mode contemplated by the inventors for carrying out the invention. This description is not meant to be construed in a limiting sense, as various alternate embodiments of the invention will become apparent to persons skilled in the art, upon reference to the description of the invention. It is therefore contemplated that such alternative embodiments form part of the present invention.

[0043] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. It is to be understood that the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0044] The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting to various embodiments. It will be further understood that the terms "comprises" and / or "comprising" used herein specify the presence of stated features, integers, steps, operations, members, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and / or groups thereof. Also, expressions such as "at least," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0045] In an embodiment of the present invention there is provided a compound of formula I having structure as:

[0046] R’-N=N-R I,

[0047] where, R’ = amino substituted aromatic rings, and R = a moiety represented by a structural formula A.

[0048] The present invention provides a compound of formula I having an antitrypanosomal activity, and is less toxic as compared to marketed drug Quinapyramine sulfate.

[0049] The R’ in the compound of formula I is an amino substituted aromatic ring selected from benzamidine acroflavine, diamidines, phenanthridinium, tryparsamide, arphenamine, tryparsamide, atoxyl, melarsen, oxophenarsine, acriflavine, diamidines, phenanthridinium, tozocide, cinnoline, pararosaniline, and 8-amino quinolone.

[0050] R is a moiety represented by a structural formula A having structure as: H

[0051] AC' '>'

[0052]

[0053] A

[0054] The moiety of the structural formula A is a structural analogue of quinapyramine, and differs with quinapyramine in respect of not having imine group.

[0055] In the context of the present invention, the term structural analogue is defined as chemical analogues, which are compounds that closely mirror another molecule’s core structure, differing only in specific atoms, functional groups, or small substructures. Despite a high chemical similarity, structural analogs are not necessarily functional analogs and can have very different physical, chemical, biochemical, or pharmacological properties. Thus, in an embodiment there is provided a structural analogue of quinapyramine, which is less toxic than quinapyramine.

[0056] In an embodiment, the compound of formula I is a compound of structural formula II, having anti-trypanosomal activity.

[0057]

[0058] where, R’ is selected from hydrogen, benzamidine, acroflavine, homidium, diamidines, phenanthridinium, tryparsamide, arphenamine, tryparsamide, atoxyl, melarsen, oxophenarsine, acriflavine, diamidines, phenanthridinium, tozocide, cinnoline, pararosaniline, and 8-amino quinolone. In a preferred embodiment, the compound of formula I / II is a compound of formula III, where R’ is H and has the structural formula as:

[0059] Or

[0060]

[0061] III

[0062] In a preferred embodiment, the compound of formula I / II is a compound of formula IV, where R’ is benzamidine, and having the structural formula as:

[0063]

[0064] IV

[0065] The compound of formula III contains Hydrogen as R’, while compound of formula IV contains 4-aminobenzidine moiety as R’. Both the compounds show antitrypanosomal activity similar to quinapyramine, however with no side effects or toxicity in small animals like rodents. The present invention thus provides a safe non-toxic analogue of quinapyamine having structure of formula II.

[0066] In an embodiment there is provided a pharmaceutical composition comprising the non-toxic analogue of quinapyamine having structure of formula II as an active ingredient and pharmaceutically acceptable excipients.

[0067] In an embodiment, there is provided a method for synthesis of the compound of formula II.

[0068] The method for synthesizing compound of formula II, comprises steps of:

[0069] iv. mixing a first precursor in diluted HC1 on ice bath with constant stirring,

[0070] v. adding aqueous solution of sodium nitrite dropwise to the solution of step (i), under constant stirring at ice bath, followed by adding a second precursor to the solution, and

[0071] vi. obtaining precipitate of compound of formula (II).

[0072] The method involves addition of a first precursor followed by a second precursor, where the first precursor and the second precursor are selected from aryl amine and quinapyramine sulphate vice versa, such that in a method the first precursor is different from the second precursor.

[0073] There is provided a method where, the first precursor is aryl amine, and the second precursor is quinapyramine sulphate. Also, there is provided a method where, the first precursor is quinapyramine sulphate, and the second precursor is aryl amine.

[0074] The aryl amine as used in the method as first precursor or second precursor is selected from amino substituted or unsubstituted benzamidine, acroflavine, homidium, diamidines, phenanthridinium, tryparsamide, arphenamine, tryparsamide, atoxyl, melarsen, oxophenarsine, acriflavine, diamidines, phenanthridinium, tozocide, cinnoline, pararosaniline, and 8-amino quinoline.

[0075] The present invention further provides method for preparation of compounds of formula III and formula IV.

[0076] The Scheme I and Scheme II below shows method for preparation of compounds

[0077] of formula III and formula IV:

[0078] Scheme-II

[0079]

[0080] The compound of formula III is prepared in a method comprising steps of: i. dissolving 4-aminobenzamidine in concentrated HC1 and water at a temperature lower than 5°C, in ice bath,

[0081] ii. adding aqueous solution of sodium nitrite dropwise in the solution of step (i), under constant stirring at ice bath, followed by adding Quinapyramine sulfate solution, and

[0082] iii. obtaining quinapyramine diazonium salt of formula III.

[0083] The present invention further provides a method for preparation of compound of formula IV, comprising steps of:

[0084] i. adding quinapyramine sulfate to the concentrated HC1, and water at ice bath under stirring,

[0085] ii. adding aqueous solution of sodium nitrite dropwise to the solution of step (i), under constant stirring at ice bath, followed by adding 4-aminobenzamidine solution, and

[0086] iii. obtaining precipitate of diazonium compound of formula IV.

[0087] The preparation of compound of Formula III and Formula IV differs in terms of precursor of the reaction process. Thin Layer Chromatography and mass spectrum confirmed the completion of both the reactions. The formation of the compound of formula IV was confirmed by Fourier transform infrared (FTIR) spectroscopy.

[0088] NMR data of compound of formula III and IV show successful incorporation of the desired group to form compound.

[0089] The compounds were further analyzed for toxicity and in-vivo efficacy against Trypanosoma evansi in mice models. The compounds were found to show similar or better parasitamia as compared to quinapyramine, with reduced cytotoxicity.

[0090] Thus, in an embodiment there is provided a composition for activity against Trypanosoma evansi, wherein the composition comprises compound of formula II, and pharmaceutical excipients. The present invention will further be demonstrated by means of examples. The examples do not limit the scope of the invention in any manner.

[0091] Example 1: Synthesis of 6-((2-amino-6-methylpyrimidin-4-yl)amino)-l,2,4-trimethylquinolin-l-ium diazonium salt of quinapyramine (III)

[0092] The synthesis of compound of formula III proceeds at below S’ C temperature and under stirring. In a beaker dissolve 1.19 ml concentrated HC1 in 10ml water with the addition of 8.1 mg 4-aminobenzamidine in it. The beaker was kept on ice bath and left for stirring. 2.5 mg NaNOi and 10ml water solution is added to the beaker drop wise for 10 minutes. The solution was left on ice bath stirring for 30 mins.

[0093] 10ml solution of Quinapyramine sulphate containing 20 mg Quinapyramine sulphate was added to the solution and stirred for 2 hours to collect the precipitate of the compound of formula III by centrifugation or by filtration (Figure 2). Throughout the reaction the temperature was maintained below S’ C temperature. The compound of formula III so obtained is named as AS-01, and the name is used interchangeably.

[0094] Example 2: Synthesis of 6-((2-amino-6-methylpyrimidin-4-yl)amino-4-(3-4-carbamimidoylphenyl)triaz- 1 -en- 1 -yl) - 1,2-dimethylquinolin- 1 -ium (diazonium salt of quinapyramine) (IV)

[0095] Complete reaction proceeds at below S’ C temperature and under stirring. In a beaker, 1.19 ml concentrated HC1 was dissolved in 10ml water followed by adding 20 mg quinapyramine sulfate to it. The beaker was kept on ice bath and with constant stirring. 2.5 mg NaNCh solution inlOml water was added drop wise for 10 minutes, and kept on ice bath for 30 minutes, after that 10 ml (4-aminobenzamaidine) solution was added and left for stirring for 2 hours to obtain the precipitate by centrifugation or by filtration.

[0096] Thin Layer Chromatography analysis was done for the precipitate obtained by the above reaction, with sample of Quinapyramine sulphate and 4-aminobenzamidine. The TLC plate was put in chloroform solution and analyzed for UV adsorption. No spot movement was observed in n-hexane. Methanol is further added dropwise to check the movement of spot. Figure 3 shows the TLC analysis of the samples confirming formation of diazonium pyramine.

[0097] The nuclear magnetic resonance (NMR) analysis of the synthesized compound was carried out at Avance III 400-MHz: Bruker NMR instrument in dimethyl sulfoxide (DMSO)-d6 by utilizing TMS (tetramethylsilane) as reference.

[0098] The synthesis of the compound was validated through a comparison of 1H NMR spectra of the compound with quinapyramine sulfate (QS). In QS peak related to 5 protons in the aromatic region at 5 6.51-8.7 ppm was observed but, in the compound, 9 protons in the aromatic region at 56.57 - 8.9 was observed and also shifting in the value of the aromatic region occurred. A distinct singlet emerged for the methyl groups in the aliphatic region at 5 3.99 for N-CH3, 5= 3.52 for N-C-CH3, and 5=2.71 for C-CH3. The chemical shifts of these methyl protons remained largely unaltered or exhibited negligible changes upon compound formation. This observation suggested the non-participation of these protons in the compound formation. The peaks due to three methyl groups appeared in the aliphatic region for compound III. Peaks due to NH2 groups did not appear in the spectra due to exchangeable protons. A singlet appeared at 11.18 ppm in QS, which shifted in the spectra of compound III. The disappearance of the -NH2 peak from the quinoline nucleus in the compound IV suggests that coupling occurs from that aniline group (Figure 4a-c).

[0099] The mass spectra of the compounds were acquired using acetonitrile solvent. The spectral data obtained from mass spectrometry were consistent with the observed molecular formulae of the compound. For instance, in mass spectra of compound III, m / z value occurs at 307 which match the expected molecular mass of quinapyramine diazonium which further confirms the formation of quinapyramine diazonium (Figure 5(a)). The compound of formula IV displayed a [M]+ ion peak at m / z 441.7818, which matched the expected value. The peak at 426.2741 was obtained after the removal of the methyl molecule (Figure 5b).

[0100] The IR spectrum of compound III (Figure 6a) confirmed the presence of characteristic functional groups. Broad absorptions in the 3435 cm-1region were assigned to N-H stretching vibrations of the amino and secondary amine groups, while peaks at 3137 cm-1and 2930.7 cm-1Corresponded to aromatic and aliphatic C-H stretches, respectively. A strong band observed at 1643 cm-1was attributed to C=N stretching of the heteroaromatic quinoline and pyrimidine rings, overlapping with aromatic C=C vibrations. The azo group (-N=N-) displayed a medium band around 1450 cm confirming its conjugation within the aromatic framework.

[0101] The FT-IR spectra of a compound IV show prominent azo bond (N=N) vibrations which are identifiable between 1504 cm-1 and 1555 cm-1, while C-N stretching occurs at 1284 cm-1. The strong aromatic ring absorption appears at 1683 cm-1 for C=C stretching and weak at 1800 cm-1 due to C=C bending. The bands due to the aromatic region in the range of 1400-1650 cm-1 are also significant as azo bond stretching appears between the bands of the aromatic region. The stretching of the aromatic region is prominent and strong. The absorption band of the azo chromophore is distinct from the C=C absorption bands which are quite evident (Figure 6b).

[0102] The absorption spectra of the compound III (Figure 7a) are recorded at 200- 800 nm using 4-fold dilution of stock solution (Img / ml) i.e. 0.25 mg / ml. The strong absorption band at 330-350 nm, which corresponds to 7t— >7t* electronic transitions of the azo group conjugated with the quinoline ring system, confirming the presence of an extended delocalized chromophore. A secondary band observed at 250-280 nm arises from localized aromatic 7t— >7t* transitions of the phenyl and quinoline fragments, while the higher energy region below 230 nm is attributed to 7t— >7t* and o— >o* transitions, along with possible contributions from n— >7t* transitions of heteroatom lone pairs. The UV absorption spectra of the compound IV are recorded at 200- 800 nm using 4-fold dilution of stock solution (Img / ml) i.e. 0.25 mg / ml and strong adsorption occurs at 292-297 nm (Abs. 4.18) due to JI-JI* transition of the azo chromophore (Figure 7b).

[0103] Example 3: Acute intramuscular toxicity study in SD rats and swiss albino (sa) mice

[0104] The acute intramuscular and intraperitoneal toxicity studies were conducted on male and female Sprague Dawley (SD) rats and Swiss Albino mice respectively as per new drugs and clinical trial rules, 2019. The control group of each sex was administered sterile water of injection. The other three dose groups of each sex were administered test item compound III and compound IV as a single dose by intramuscular (UM) route in rats and intraperitoneal (I / P) route in mice and animals were observed 14 days for the signs of toxicity, mortality for macroscopic and macroscopic finding. The animals were sacrificed by CO2 euthanasia and subjected to a complete necropsy on 15 days. The animals were observed daily during the quarantine and acclimatization period and treatment period, for the recording of clinical signs. After the treatment, all the animals were observed immediately after dosing once during first 30 minutes and first 24 hours with special attention during the first 2 to 4 hours after beginning of exposure period for signs of toxicity and after that early on each day and again in the afternoon for the period of 14 days. Body weights were recorded after the animals were received at the test facility, at the end of the acclimatization period (during grouping and allocation), prior to dosing and prior to sacrifice. An increasing trend of weight gain has been seen in all the treated mice at the end of experimental period of 14 days and no mortality was observed in the treated animals. All sacrificed animals were necropsied and examined macroscopically. No external and internal abnormalities were detected in any of the animal during necropsy. No mortality was observed with test item Compound III and Compound IV by the intramuscular and intraperitoneal routes in male and female SD rats and Swiss Albino mice respectively, Example 4: Cytotoxicity evaluation on Vero cell lines

[0105] The cytotoxic activity was assessed for compound III, compound IV and Quinapyramine by colorimetric assay using resazurin dye (7 -Hydroxy- 3 H-phenoxazin-3-one 10-oxide) at different concentrations. Vero cells at a density of 1 x 104cells per well were cultured in 100 pL of cell culture medium in a 96 -well cell culture plate at 37°C in 5% CO2, At 70% confluency, cultured cells were treated with QS and Compound III and IV (1000-125pg / ml) and incubated again for 24 hrs as above. After incubation, the samples were treated with 10 pl of the resazurin solution prepared in DMEM (1 mg / ml) and incubated for 4 hrs at conditions specified above. After 4 hrs blue color changes to the pink coloured resorufin proportionally to cellular metabolic activity and absorbance was recorded by spectrophotometer (ELISA plate reader, Power Wave XS2) at 590 nm. Cytotoxicity percentage was calculated with reference to untreated cells after normalizing the background coloration of media.

[0106] % Cytotoxicity = (OD1- OD2) / OD1 x 100

[0107] OD1 and OD2 were absorbance of untreated control and samples treated with nanoformulation respectively.

[0108] The results as shown in Figure 8(a) and 8(b) confirms that QS exhibited greater cytotoxicity as compared to Compound III and IV at all the concentrations tested.

[0109] Example 5: In vivo anti-trypanosomal activity of quinapyramine sulfate The compound III was further analyzed for in-vivo efficacy against Trypanosoma evansi in mice models. The mice were divided into four groups. Group I was infected and treated with conventional drug Quinapyramine at recommended dose of 5mg / kg; Group II was infected and treated with Compound III at a dose of 4mg / kg, Group III was infected, but not provided with any medication; and Group IV was uninfected and untreated. Group I, II and IV animals survived, while Group III animals died in 8-10 days (Figure 9). Thus, it was concluded that a low dose of compound of formula III (4mg / kg) is equally effective as compared to a 5mg / kg dose of Quinapyramine.

[0110] Example 6: Percent parasitemia and Mortality analysis in mice

[0111] The percent parasitemia for the compounds of formula III and formula IV was evaluated. The Group II animals of Example 5 were evaluated for evaluation of percent parasitemia for compound of formula III.

[0112] The compound of formula III showed 80% reduction in parasites in 2 days of treatment, while complete 100% reduction achieved within 2-3 days of treatment, whereas in case of compound of formula Quinapyramine sulfate, the effect of reduction in parasites was achieved after 3 days of treatment (Figure 10). Thus, the compound of formula III, not only is less toxic, also shows early treatment effect compared to quinapyramine.

[0113] The Compound IV was also analyzed for percent parasitemia. The mice were divided into four groups. Mice in Groups I, II, III and IV were infected with 104T. evansi parasites intraperitoneally. After 24 hrs, Group I was treated with Compound IV at a dose of 4mg / kg bwt; Group II mice were given 2mg / kg bwt. Group III mice were treated with conventional drug quinapyramine sulfate at dose of 2mg / kg bwt; Group IV mice were infected, but not provided any medication; and Group V mice were uninfected and untreated.

[0114] These were evaluated for mortality and percent parasitaemia for 90 day period. Group I, II, III and V animals survived, while Group IV animals died in 8-10 days. Mice in Groups I, II, III and V exhibited 100% survival rate, with no signs of parasitemia (0% infection), indicating that these mice remained healthy throughout the study. In contrast, Group IV mice showed 100% parasitemia, as all mice in this group were infected and succumbed to the infection by the 8- 10th day, resulting in a 0% survival rate by the end of the experiment (Figure 11). Hence, tests confirmed no parasite load in mice after therapy. These results show that Compound IV formulation works well against T. evansi, with conventional treatment also being effective.

[0115] ADVANTAGE OF THE INVENTION

[0116] The present invention provides compounds having efficacy against Trypanosoma evansi, with less cytotoxic effect compared to marketed drug Quinapyramine sulfate. The non-toxic compounds are structural analogue of Quinapyramine and has similar or better effect compared to Quinapyramine, with reduced side effects.

Claims

CLAIMS:

1. A compound having structural formula I asR’-N=N-R Iwhere, R’ is amino substituted aromatic rings, andR is a moiety represented by a structural formula A as2. The compound as claimed in claim 1, wherein the compound a compound having structural formula II as:

3. The compound as claimed in claim 1 or claim 2, wherein the R’ is selected from benzamidine acroflavine, diamidines, phenanthridinium, tryparsamide, arphenamine, tryparsamide, atoxyl, melarsen, oxophenarsine, acriflavine, diamidines, phenanthridinium, tozocide, cinnoline, pararosaniline, and 8-amino quinolone.

4. The compound as claimed in claim 1 or claim 2, wherein the compound is compound of structural formula III:

5. The compound as claimed in claim 1 or claim 2, wherein the compound is compound of structural formula IV:

6. A method for preparing compound of formula II of claim 2 comprising steps of:i. mixing a first precursor in diluted HC1 on ice bath with constant stirring,ii. adding aqueous solution of sodium nitrite dropwise to the solution of step (i), under constant stirring at ice bath, followed by adding a second precursor to the solution, andiii. obtaining precipitate of compound of formula (II).

7. The method as claimed in claim 6, wherein the first precursor and the second precursor are selected from aryl amine and quinapyramine sulphate vice versa, such that the first precursor is different from the second precursor in the method.

8. The method as claimed in claim 6, wherein the aryl amines are selected from benzamidine, acroflavine, homidium, diamidines, phenanthridinium, tryparsamide, arphenamine, tryparsamide, atoxyl, melarsen, oxophenarsine, acriflavine,diamidines, phenanthridinium, tozocide, cinnoline, pararosaniline, and 8-amino quinoline.

9. A structural analogue of quinapyramine having structure of formula II as claimed in claim 2.

10. A pharmaceutical composition comprising the compound as claimed in claim 1, as an active ingredient and a pharmaceutically acceptable excipients.

Images