WO1997006161A1 - Anticoccidial 8-aminoquinoline derivatives - Google Patents

Abstract

Compounds of formula (I) non-toxic salts thereof, and non-toxic solvates of either entity, wherein A is C2-C10 alkylene, C4-C6 alkenylene, C4-C6 alkynylene or C5-C7 cycloalkylene; B is a direct link or C1-C6 alkylene; W is O, S, SO or SO2; R1 is OH, C¿1?-C4 alkoxy or C1-C4 alkyl; R?2¿ is H; halo; OH; C¿1?-C4 alkoxy; C1-C4 alkylamino; di C1-C4 alkylamino; C2-C4 alkenyl optionally substituted with phenyl, CO2(C1-C4 alkyl), CN or CONH2; or phenyl or phenoxy optionally substituted with one or two substituents selected from C1-C4 alkyl, C1-C4 alkoxy, halo, CF3 and amino; R?3¿ is H; halo; C¿2?-C4 alkenyl optionally substituted with phenyl, CO2(C1-C4 alkyl), CN or CONH2; phenyl optionally substituted with one or two substituents selected from C1-C4 alkyl, C1-C4 alkoxy, halo, CF3 and amino; thienyl; furyl or pyridyl; R?4¿ is H or C¿1?-C4 alkyl; R?5¿ is H; C¿1?-C4 alkyl; C1-C4 alkoxy; halo; C2-C4 alkenyl optionally substituted with phenyl, CO2(C1-C4 alkyl), CN or CONH2; phenyl or phenoxy optionally substituted with one or two substituents selected from C1-C4 alkyl, C1-C4 alkoxy, halo, CF3 and amino; thienyl; furyl or pyridyl; R?6¿ is H or C¿1?-C4 alkyl; R?7¿ is H or C¿1?-C4 alkoxy; m is 1, 2 or 3; n is 0, 1, 2, 3 or 4; and p is 0 or 1; have broad spectrum anticoccidial activity and thus are useful in the treatment or prevention of coccidiosis, and also for performance enhancement, in animals.

Description

ANTICOCCIDIAL 8-AMINOQUINOLINE DERIVATIVES

The present invention relates to certain novel 6-hydroxy-8-aminoquinoline and 6-alkoxy-8-aminoquinoline derivatives which have broad-spectrum anticoccidial activity and thus are useful in the treatment or prevention of coccidiosis, and also for performance enhancement (increased rate of growth and/or increased efficiency of feed utilisation), in animals.

Protozoan parasites can cause a variety of diseases in both livestock and companion animals, the most economically important of these diseases being coccidiosis. The majority of coccidia of importance in domestic animals belongs to the genus Eimeria which can infect a wide range of hosts including cattle, sheep, goats, poultry, pigs, cats and dogs; of these hosts, the resulting disease is most widespread in poultry. The life cycle of all the species includes the passing of oocysts with the faeces and thus the disease can spread rapidly when oocysts are ingested, for example, by birds. Where young birds are placed on heavily contaminated litter, deaths may occur within a few days and entire flocks can be wiped out. Thus the intensive rearing of birds is dependent on the availability of effective anticoccidial agents. Field resistance occurs to all the existing anticoccidials, thus reducing their efficacy, and resistance development has been very rapid for some of the anticoccidials rendering them virtually useless after a short period. The future health of poultry and other species affected by coccidiosis requires the development of new agents, not cross-resistant with all the existing classes, to replace the older products as they become ineffective. There is, therefore, a continuing need for new anticoccidial agents.

Although the antimalarial activity of 6-a!koxy-8-aminoquinoline derivatives is well known, only two of these compounds are known to have limited anticoccidial activity. Primaquine, 8-(5-amino-2-pentylamino)-6-methoxyquinoline, and pamaquine, 8-(5-diethylamino-2-pentylamino)-6-methoxyquinoline. have useful activity against Eimeria tenella and Eimeria necatrix, but are ineffective against Eimeria acervulina. Eimeria brunetti and Eimeria maxima rendering them of little value for the control of coccidiosis (see J. Vet. Med. Sci., 1991 J53, 13). It has now been discovered that the novel compounds of the invention have broad-spectrum anticoccidial activity against all the species of Eimeria identified above and, moreover, are significantly more potent than primaquine and pamaquine. In addition they have activity against resistant strains of Eimeria which are not controlled by the existing classes of anticoccidial drugs, in particular against those Eimeria sp. which are resistant to the polyether ionophores such as salinomycin, maduramycin, lasalocid and monensin.

Furthermore, the compounds of the invention have utility in the treatment or prevention of certain other protozoal diseases of domestic animals, for example those caused by Cryptosporidia SD.. Neospora sp. and Isospora so. whereas, in general, antimalarial drugs do not have utility in the treatment or prevention of diseases caused by gut-dwelling parasites such as Eimeria s^p. and Cryptosporidia so. The finding that the compounds of the invention are useful in such disease control is therefore unexpected.-

It has also been discovered that when the said compounds are administered to healthy animals they cause performance enhancement and, consequently, may cause the treated animals to grow at a faster rate than untreated animals and/or improve the feed conversion ration (FCR) of the treated animals, i.e. less food is needed to achieve the same weight gain.

Thus the present invention provides compounds of formula (I):

non-toxic salts thereof, and non-toxic solvates (including hydrates) of either entity, wherein A is C₂-C₁₀ alkylene, C -C₆ alkenylene, C₄-C₆ alkynylene or C₅-C₇ cycloalkylene;

B is a direct link or Ci-Ce alkylene; W is O, S, SO or S0₂; R¹ is OH, C C alkoxy or C C₄ alkyl;

R² is H; halo; OH; C C alkoxy; d-C alkylamino; di d-C alkylamino; C₂-C₄ alkenyl optionally substituted with phenyl, C0₂(C C alkyl), CN or CONH₂; or phenyl or phenoxy optionally substituted with one or two substituents selected from C-ι-C₄ alkyl, C-ι-C alkoxy, halo, CF₃ and amino;

R³ is H; halo; C₂-C₄ alkenyl optionally substituted with phenyl, C0₂(d- C alkyl), CN or CONH₂; phenyl optionally substituted with one or two substituents selected from C C₄ alkyl, C C alkoxy, halo, CF₃ and amino; thienyl; furyl or pyridyl; R⁴ is H or C C₄ alkyl;

R⁵ is H; Cι-C₄ alkyl; d-C alkoxy; halo; C₂-C₄ alkenyl optionally substituted with phenyl, C0₂(C.-C₄ alkyl), CN or CONH_2; phenyl or phenoxy optionally substituted with one or two substituents selected from Cι-C alkyl, C C₄ alkoxy, halo, CF₃ and amino; thienyl; furyl or pyridyl;

R⁶ is H or C.-C₄ alkyl; R⁷ is H or d-C alkoxy; m is 1 , 2 or 3; n is 0, 1 , 2, 3 or 4; and p is O or l .

In the above definition, halo means fluoro, chloro, bromo or iodo. Unless otherwise indicated, alkenylene or alkynylene groups having five or more carbon atoms, alkyl, alkoxy, alkenyl and alkylene (in the definition of A) groups having three or more carbon atoms, and alkylene (in the definition of B) having two or more carbon atoms, may be straight chain or branched chain. The compounds of formula (I) may contain one or more asymmetric centres and thus can exist as stereoisomers, i.e. as enantiomers or as diastereoisomers. Furthermore, compounds of formula (I) which contain alkenyl or alkenylene groups can exist as cis-stereoisomers or trans-stereoisomers. In each instance, the invention includes both the separated individual stereoisomers as well as mixtures thereof.

The non-toxic salts of the compounds of formula (I) are, for example, acid addition salts formed with inorganic acids such as hydrochloric, hydrobromic, sulphuric, nitric and phosphoric acid, with organo-carboxylic acids, or with organo- sulphonic acids. Certain compounds of formula (I) can also provide non-toxic metal salts, in particular alkali metal salts, with bases. Examples include the sodium and potassium salts.

A preferred group of compounds of formula (I) is that wherein A is C₂-C-ιo alkylene; R¹ is OH; R² and R³ are H; R⁴ is H or C1-C4 alkyl; R⁵ is H, C C alkyl, C C₄ alkoxy or halo; R⁶ is C C₄ alkyl and R⁷ is H. A more preferred group of compounds of formula (I) is that wherein A is C₂-

C₈ alkylene; B is a direct link or methylene; R⁴ is H or methyl; R⁵ is H, methyl, methoxy or bromo; R⁶ is methyl; m is 2 or 3 and n is 0, 2 or 3.

A particularly preferred group of compounds of formula (I) is that wherein A is C -C₅ alkylene; W is O, S or SO and R⁵ is H or bromo. A more particularly preferred group of compounds of formula (I) is that wherein A is (CH₂)₅; W is O; n is 0 and p is 0.

Especially preferred individual compounds of the invention include: 6-methoxy-8-[5-(4-tetrahydropyranylamino)-1-pentylamino]quinoline; 5-bromo-6-methoxy-8-[5-(4-tetrahydropyranylamino)-1-pentylamino]- quinoline; 6-methoxy-4-methyl-8-[5-(4-tetrahydropyranylamino)-1-pentylamino]- quinoline;

6-methoxy-8-[5-(2-tetrahydrofurylmethylamino)-1-pentylamino]quinoline; and 6-methoxy-8-[5-(3-tetrahydrofurylamino)-1-pentylamino]quinoline; and non-toxic salts thereof, and non-toxic solvates (including hydrates) of either entity.

In a further aspect, the present invention provides processes for the preparation of compounds of formula (I), their non-toxic salts, and non-toxic solvates (including hydrates) of either entity, as illustrated below. It will be appreciated by persons skilled in the art that, within certain of the processes described, the order of the synthetic steps employed may be varied and will depend inter alia on factors such as the nature of other functional groups present in a particular substrate, the availability of key intermediates, and the protecting group strategy (if any) to be adopted. Clearly, such factors will also influence the choice of reagent for use in the said synthetic steps. It will also be appreciated that various standard substituent or functional group interconversions and transformations within certain compounds of formula (I) will provide other compounds of formula (I); examples are sulphide to sulphoxide or sulphone, alkene or alkyne to alkane, and halo to hydroxy, alkoxy, phenoxy, amino, alkenyl, aryl or heteroaryl. A compound of formula (1) may be obtained by N-monoalkylation of a compound of formula (II):

wherein A, R^2, R³, R⁴, R⁵, R⁶ and R⁷ are as previously defined for formula (I), using one or more of the following methods.

li By reaction of a compound of formula (II) with a compound of formula (III):

wherein B, W, R¹, m, n and p are as previously defined for formula (I) and X is a suitable leaving group, e.g. halo (preferably chloro, bromo or iodo), C C alkanesulphonyloxy, trifiuoromethanesulphonyloxy or arylsulphonyloxy (preferably benzenesulphonyloxy or p-toluenesulphonyloxy), in the presence of an appropriate base, e.g. sodium or potassium carbonate or bicarbonate, or triethylamine, in a suitable solvent such as a Cι-C₄ alkanol, 1 ,2-dimethoxyethane, acetonitrile, dimethylformamide or N,N-dimethylacetamide. and optionally in the presence of sodium or potassium iodide. If necessary, the primary and/or secondary amino group present in (II) may be protected using a conventional amine-protecting group, e.g. benzyl, benzyloxycarbonyl, t-butoxycarbonyl or 2,2,2- trichloroethoxycarbonyl. The reaction can be conducted at from about 0°C to about 150°C, preferably at from about room temperature to about 100°C, and, where appropriate, is followed by a standard amine-deprotection step.

2a. When B is not a direct link, by reaction of a compound of formula (II) with, depending on whether B is unbranched or branched α to the distally disposed (with respect to the quinoiine ring) amino group, an aldehyde or ketone respectively of formula (IV):

wherein W, R¹, m, n and p are as previously defined for formula (I) and

O = B' is a carbonyl-containing B precursor. The reductive amination may be carried out under conventional catalytic hydrogenation conditions, or by using sodium cyanoborohydride in a suitable solvent such as methanol or ethanol at about room temperature, or by using sodium triacetoxyborohydride optionally in the presence of glacial acetic acid in a suitable solvent such as tetrahydrofuran, dichloromethane or 1 ,2-dichloroethane at about room temperature, or by exploiting Lewis acid activation, e.g. using anhydrous zinc chloride. Alternatively, the reductive alkylation may be achieved by a two-step procedure in which the intermediate enamine is formed initially, under conventional conditions, and subsequently reduced to the required amine, e.g. using sodium cyanoborohydride in tetrahydrofuran-methanol at about room temperature. 2b. When B is a direct link, by reaction of a compound of formula (II) with a ketone of formula (V):

wherein W, R¹, m, n and p are as previously defined for formula (I), under the conditions described above in variant 2a.

One preferred procedure involves the reaction of (II) with (V) in the presence of sodium cyanoborohydride in a suitable solvent, e.g. methanol, at about room temperature, using an acid such as hydrochloric acid or methanolic hydrogen chloride to achieve the optimal reaction pH.

In another preferred procedure, (II) is reacted with (V) under mild catalytic hydrogenation conditions using prehydrogenated platinum oxide in a suitable solvent, e.g. ethanol; typical hydrogenation conditions are a pressure of 207kPa (30psi) and room temperature.

3i When the compound of formula (I) is a N-2-glycosyl analogue, by direct condensation of (II) with the corresponding aldose in a suitable solvent, e.g. an aqueous CrC₃ alkanol, preferably ethanol, at from about 20 °C to about 25 °C.

An alternative approach to a compound of formula (I), wherein A is not C₅-C₇ cycloalkylene, may involve a "reverse" N-monoalkyiation strategy, whereby a compound of formula (VI):

wherein R², R³, R , R⁵, R⁶ and R⁷ are as previously defined for formula (I), X is as previously defined for formula (III), and A' is C₁-C₉ alkylene, C₃-C₅ alkenylene or C₃-C₅ alkynylene, is reacted with an amine of formula (VII):

wherein B, W, R¹, m, n and p are as previously defined for formula (I), to provide an amide of formula (VIII):

followed by reduction of the amidic carbonyl group to a methylene group.

The reaction may be carried out as described previously for the reaction of (II) with (III) in variant 1 , using a conventional amine-protecting group strategy for (VII) where appropriate.

When the amine of formula (VII) is readily accessible, it is convenient to employ it in large excess since it also serves as solvent and as an acid scavenger with respect to the HX released during the alkylation. Preferably the reaction is conducted using at least a 2.5-fold excess of (VII) at about 100°C.

Reduction of the intermediate amide of formula (VIII) may be achieved using lithium aluminium hydride, optionally in the presence of aluminium chloride, in a suitable anhydrous solvent, e.g. tetrahydrofuran, ether or 1 ,4-dioxan, at from about 0°C to about 100°C. Typically, when no other susceptible group is present, the reaction is carried out using an excess of the reducing agent and about one equivalent of aluminium chloride in anhydrous tetrahydrofuran at from about 0°C to about 5°C.

An obvious variant of the above two-step altemative, which is also feasible when A is C5-C7 cycloalkylene, is to react an amine of formula (VII) with a compound of formula (IX):

wherein A, R², R³, R⁴, R⁵, R⁶ and R⁷ are as previously defined for formula (I) and X is as previously defined for formula (III), under the N-monoalkylation condition already described. A further process for synthesing a compound of formula (I) comprises reacting a compound of formula (X):

wherein R², R³, R⁴, R^5, R⁶ and R⁷ are as previously defined for formula (I) and A'= O is a carbonyl-containing A precursor, which may be an aldehyde or ketone depending on whether A is unbranched or branched respectively a to the distally disposed (with respect to the quinoline ring) amino group, with an amine of formula (VII) under the reductive amination conditions previously described. This is a particularly convenient route for a compound of formula (I) wherein A is C₅-C₇ cycloalkyl because of the ready accessibility of monoprotected cycloalkanediones, e.g. 1 ,4-cyclohexanεdione monoethylene ketal.

Compounds of formulae (II), (VI), (IX) and (X) may be assembled directly from the corresponding 8-aminoquinoline; altematively (II) may be generated via (IX). In either case, the terminal amino group is preferably introduced in protected form, e.g. as a phthalimido or di-t-butoxycarbonylamino moiety.

Particularly convenient ways of generating a compound of formula (II) are to treat the 8-aminoquinoline either with the appropriate ω-phthalimidoalkyl bromide, followed by deprotection of the amino group using hydrazine hydrate, or with the appropriate ω-cyanoalkyl bromide, followed by reduction of the cyano group using lithium aluminium hydride, as illustrated in the Preparations section. Th e skilled person will appreciate that certain of the quinoline substituents defined for a compound of formula (I), in particular R², R³ and R⁵, may be introduced either after the final step of a synthetic sequence, i.e. into another compound of formula (I), or at some earlier stage into a suitable intermediate when more appropriate. For example, conversion of R² is H into R² is chloro or bromo may be effected via the intermediacy of the derived quinoline N-oxide using phosphorus oxychloride or phosphorus oxybromide respectively. Further processing of either 2-haloquinoline derivative produced may be exploited to provide 2-hydroxy, 2-(Cι-C₄ alkoxy) or 2-phenoxy analogues using, for example, an alkali metal hydroxide, C C alkoxide or phenoxide respectively or, alternatively, to provide 2-(CrC alkylamino) or 2-(di C C alkylamino) analogues using the corresponding primary or secondary amine respectively as the nucleophile. The particularly versatile 2-bromoquinoline derivative may also be subjected to palladium-catalysed coupling either via a Heck reaction with the appropriate styrene, acrylic ester or acrylamide to afford the required 2-alkenyl analogue or via a Suzuki reaction with the appropriate arylboronic acid to furnish the required 2-aryl analogue. Preferably, the Heck reaction is conducted using an excess of the required alkene, in the presence of palladium(ll) acetate, tri-o-tolylphosphine and triethylamine, in a suitable solvent such as acetonitrile or dimethylformamide, at from about 80°C to about 160°C.

Preferably, the Suzuki reaction is carried out using one equivalent of the required arylboronic acid and of sodium bicarbonate, in the presence of tetrakis(triphenylphosphine)palladium(0), in a suitable solvent such as a mixture of toluene and ethanol, at about 100°C.

Analogous Heck and Suzuki chemistry may be applied to the R³ and R⁵ positions of the quinoline nucleus where, additionally, the heteroaryl substituents may be introduced using the corresponding boronic acids. Such acids^' are obtainable from the appropriate heteroaryllithium and tri(Cι-C₄ alkyl)borate, followed by hydrolysis of the intermediate borate ester. The required 5-bromoquinoiine may be obtained by direct electrophilic substitution using, for example, tetra-n-butylammonium tribromide or bromine in a suitable solvent such as dichloromethane or chloroform at from about 0°C to about 40°C. Altematively, N-bromosuccinimide may be employed under similar conditions. The corresponding 5-chloroquinoline may be obtained using chlorine in glacial acetic acid and the 5-iodo analogue using iodine monochloride in glacial acetic acid, each at from about room temperature to about 100°C. Altematively, N-chiorosuccinimide or N-iodosuccinimide respectively, in dichloromethane or chloroform at from about 0°C to about 40°C, may be employed. in the R⁶ position, conversion of C-ι-C alkoxy into hydroxy may be achieved by standard dealkylation procedures, ranging from the use of concentrated hydrobromic acid at about 100°C to the use of boron tribromide in dichloromethane at from about -70 °C to about 25 °C.

With respect to other standard substituent transformations alluded to earlier, a compound of formula (I), or an intermediate thereto, wherein W is S may be transformed to the corresponding sulphoxide or sulphone either by controlled oxidation using ca. a stoichiometric amount of oxidising agent, or by using the required excess of oxidising agent, respectively, in an appropriate solvent.

Suitable oxidising agents are, for example, a peracid such as m-chloroperbenzoic acid, sodium periodate, hydrogen peroxide or potassium permanganate. A preferred reaction for converting a sulphide to a sulphoxide involves the use of sodium periodate in aqueous methanol at from about 20 °C to about 25 °C. A compound of formula (I), or an intermediate thereto, wherein A is C₄-C₆ alkenylene or C -C₆ alkynylene may be transformed to the corresponding derivative wherein A is C -C₆ alkylene by conventional catalytic or catalytic transfer hydrogenation. The intermediates of formulae (III), (IV), (V) and (VII) when neither commercially available nor subsequently described, can be obtained either by analogy with the processes described in the Preparations section or by conventional synthetic procedures, in accordance with standard textbooks on organic chemistry or literature precedent, from readily accessible starting materials using appropriate reagents and reaction conditions.

Moreover, persons skilled in the art will be aware of variations of, and altematives to, those processes described hereinafter in the Examples and Preparations sections which allow the compounds defined by formula (I) to be obtained.

The non-toxic acid addition salts of the compounds of formula (I) may also be prepared in a conventional manner. For example a solution of the free base is treated with the appropriate acid, either neat or in a suitable solvent, and the resulting salt isolated either by filtration or by evaporation under reduced pressure of the reaction solvent. Non-toxic base salts can be obtained in an analogous manner by treating a solution of a compound of formula (I) with the appropriate base. Both types of salt may be formed or inte rcon verted using ion-exchange resin techniques.

The anticoccidial activity of the compounds of the present invention was determined by the following in vivo test method.

Groups of five 7- to 8-day old Ross Broiler pullets were fed a meal diet containing the test compound uniformly dispersed therein. After 32 to 48 hours on this ration, each chick was inoculated βer os with oocysts of ionophone resistant Eimeria tenella and Eimeria acervulina, or Eimeria maxima. Other groups of five 7- to 8-day old chicks were fed the same meal diet without the test compound, then infected after 32 to 48 hours as above to provide the control groups. A further group of five 7- to 8- day old chicks was fed with the same meal diet without the test compound and was not subsequently infected. The results obtained with the three types of group were evaluated by visual scoring of intestinal and caecal lesions at 6 days post-challenge in the case of E. tenella and E. acervulina and at 7 days post-challenge in the case of E. maxima. For E. maxima, a total faecal collection was also made for each group over the 24-hour period prior to autopsy, i.e. from day 6 to day 7 post-challenge, and a sub-sample retained for faecal oocyst counting. The criteria used to measure anticoccidial activity consisted of lesion scores of 0 to 4 for all Eimeria species : see D.P. Conway and M.E. McKenzie, Poultry Coccidiosis-Diagnostic and Testing Procedures, Pfizer Inc., New York, second edition (1979). Faecal oocysts were counted using a modified McMaster salt flotation technique : see Manual of Veterinary Parasitological Laboratory Techniques, HMSO, London (1977), the faecal samples being suspended in saturated sodium chloride solution prior to sieving, and not centrifuged. The compounds of the invention were found to exhibit convincing anticoccidial activity when incorporated into the diet at from 1 to 100 parts per million (ppm). The performance enhancement activity of the compounds of the invention was determined as follows.

Groups of five 1-day old Ross Broiler pullets were fed a meal diet containing the test compound uniformly dispersed therein. Other groups of five 1-day old chicks, which served as the normal controls, were fed a meal diet without the test compound. The chicks were group-weighed at the start of the experiment (day 0) and again on days 7, 14 and 21 , and feed consumption per group was measured at each of the weigh-points. Four replicates of five chicks per treatment were used.

The criteria used to measure performance enhancement were weight gain and feed conversion: weight gain index (WGI) =

mean weight gain for medicated birds mean weight gain for non-medicated birds

feed conversion ratio (FCR) =

mean weight of feed consumed mean weight gain

The compounds of the invention elicited a WGI>1 and a lower FCR.

Evaluation of anticoccidial and performance enhancement activity in cattle and sheep was carried out according to the methods described in Amer. J. Vet. Res., 1979, 40, 97; jbjd., 1981 , 42, 54 and ibid., 1981 , 42, 57.

For use in the treatment of coccidiosis in poultry a compound of the invention may be administered orally in a suitable carrier. Conveniently, the medication is simply carried in the drinking water or in the poultry feed, so that a therapeutic dosage of the agent is ingested with the daily water or poultry ration. The agent can be directly metered into drinking water, preferably in the form of a liquid, water-soluble concentrate (such as an aqueous solution of a non-toxic, water¬ soluble salt) or added directly to the feed, as such, or in the form of a supplement premix or concentrate. A premix or concentrate of the therapeutic agent in a carrier is commonly employed for the inclusion of the agent in the feed. Suitable carriers are liquid or solid, as desired, such as water, various meals e.g. soybean oil meal, linseed oil meal and corncob meal, and mineral mixes as are commonly employed in poultry feeds. A particularly effective carrier is thε poultry feed itself i.e. a small portion of poultry feed. The carrier facilitates uniform distribution of the active materials in the finished feed with which the premix is blended. This is important because only small proportions of the present potent agents are required. It is important that the compound is thoroughly blended into the premix and, subsequently, the feed. In this respect, the agent may be dispersed or dissolved in a suitable oily vehicle such as soybean oil, corn oil, cottonseed oil and the like, or in a volatile organic solvent, and then biended with the carrier. It will be appreciated that the proportions of active material in the concentrate are capable of wide variation since the amount of agent in the finished feed may be adjusted by blending the appropriate proportion of premix with the feed to obtain a desired level of therapeutic agent.

High potency concentrates may be blended by the feed 'manufacturer with proteinaceous carrier such as soybean oil meal and other meals, as described above, to produce concentrated supplements which are suitable for direct feeding to poultry. In such instances, the poultry is permitted to consume the usual diet. Altematively, such concentrated supplements may be added directly to the poultry feed to produce a nutritionally balanced, finished feed containing a therapeutically effective level of the compound of the invention. The mixtures are thoroughly blended by standard procedures, such as in a twin shell blender, to ensure homogeneity.

It will, of course, be obvious to those skilled in the art that the use levels of the compounds described herein will vary under different circumstances. Continuous low-level medication, during the growing period i.e. during the first 6 to 12 weeks for chickens, is an effective prophylactic measure. In the treatment of established infections, higher levels may be necessary to overcome the infection. The use level in feed will generally be in the range of from 1 to 100 ppm. When administered in drinking water, the level will be that which will provide the same daily dose of medication, i.e. from 1 to 100 ppm, factored by the weight ration of the average daily consumption of feed to the average daily consumption of water. Altematively, a compound of the invention may be administered by injection, implant or as a pour-on or spot-on formulation, the required formulations being prepared in a conventional manner in accordance with standard veterinary practice. Injectable formulations, for example, may be prepared in the form of a sterile solution or emulsion for subcutaneous or intramuscular administration. The formulation will vary with regard to the weight of active compound, which will depend on the species of host animal to be treated, the severity and type of infection and the body weight of the host. The method, level, frequency and duration of dosing required will, in any case, be determined by the veterinary surgeon. In general, the dose level will be in the range of 2 to 200mg/Kg.

Thus the invention provides a composition for treating animals comprising a compound of formula (I), or a non-toxic salt thereof, or a non-toxic solvate (including hydrate) of either entity, together with a suitable diluent or carrier.

The invention further provides a compound of formula (I), or a non-toxic salt thereof, or a non-toxic solvate (including hydrate) of either entity, or a composition containing any of the foregoing^', for use in the treatment or prevention of protozoal diseases, or in performance enhancement in animals. Furthermore, the invention provides a compound of formula (I), or a non¬ toxic salt thereof, or a non-toxic solvate (including hydrate) of either entity, or a composition containing any of the foregoing, for the manufacture of a medicament for the treatment or prevention of protozoal diseases, or for performance enhancement, in animals. Still further, the invention provides a method of treating animals to cure or prevent a protozoal disease, or to enhance performance, which comprises treating said animals with an effective amount of a compound of formula (I), or a non-toxic salt thereof, or a non-toxic solvate (including hydrate) of either entity, or a composition containing any of the foregoing. The intermediates of formulae (II), (VIII) and (IX) also form part of the invention. The syntheses of the compounds of the invention and of the intermediates for use therein are illustrated by the following Examples and Preparations. The purity of the compounds (Rf) was routinely monitored by thin layer chromatography using neutral alumina-coated plates and the following solvent systems (SS):

1. dichloromethane: methanol, 95:5; 2. ethyl acetate : methanol, 95:5;

3. ethyl acetate;

4. dichloromethane : methanol, 90:10;

5. dichloromethane : ethyl acetate, 95:5.

H Nuclear magnetic resonance (NMR) spectra were recorded using a

Bruker AC-300 spectrometer and were in all cases consistent with the proposed structures. Characteristic chemical shifts (δ) are given in parts-per-million downfield from tetramethylsilane using conventional abbreviations for designation of major peaks: e.g. s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; b, broad.

Mass spectra (m/z) were recorded using a Fisons Instruments Trio mass spectrometer in the thermospray mode.

Room temperature means 20°C-25°C.

EXAMPLE 1 6-Methoxy-8-f5-f4-tetrahvdropyranylamino)-1-pentylamino1αuinoline hvdrochloride A mixture of 8-(5-amino-1-pentyiamino)-6-methoxyquinoiine (Preparation 4;

1.44g, 5.55 mmol), 4-tetrahydropyranone (280mg, 2.79 mmol), sodium cyanoborohydride (104mg, 1.66 mmol), a 9.2M solution of hydrogen chloride in methanol (4 drops) and methanol (6ml) was stirred at room temperature for 24 hours and then evaporated under reduced pressure. The resulting viscous oil was dissolved in 1 M hydrochloric acid (30ml) and the solution washed with ether (3 x 10ml), basified to pH 10 with solid sodium hydroxide, saturated using sodium chloride and extracted with ether (3 x 15ml). Evaporation under reduced pressure of the dried (Na₂S0 ), combined extracts provided an oil which was dissolved in the minimum volume of dry 1 -propanol and then neutralised with 1 equivalent of a 9.2M solution of hydrogen chloride in methanol. The resulting buff precipitate was collected, washed with dry 1 -propanol and dried in vacuo to give the title compound (388mg). δ (CDCI₃) for free base: 3.40 (2H, td), 3.50 (1H, t), 3.90 (3H, s), 3.97 (2H, dt), 6.10 (1H, t), 6.27 (1H, d), 6.37 (1H, d), 7.30 (1H, q), 7.95 (1H, dd), 8.55 (1H, d). m/z 344 (m+H)⁺.

EXAMPLE 2 6-Methoxy-8-r5-(3-tetrahvdrothiopyranylamino)-1-pentylamino1αuinoline hvdrochloride

The title compound (820mg) was obtained by a procedure similar to that described in Example 1 but using ca. 1 molecular equivalent of the quinoline derivative and ca. 1.45 molecular equivalents of sodium cyanoborohydride, i.e. the title compound of Preparation 4 (1.0g, 3.86 mmol), 3-tetrahydrothiopyranone (445mg, 3.83 mmol) and sodium cyanoborohydride (290mg, 5.57 mmol) in methanolic hydrogen chloride at pH 6. Rf 0.87 (SS1). δ (CD₃OD): 1.60-2.00 (10H, m), 2.20 (2H, m), 2.60 (2H, m), 2.90 (1 H, m), 3.10 (2H, m), 3.40 (2H, t), 4.00 (3H, s), 6.90 (1 H, s), 7.90 (2H, 2xd), 8.85 (1H, dd), 8.90 (1 H, d). m/z 360 (M+H)⁺. EXAMPLE 3 6-Methoxy-8-r5-f3-tetrahvdrothienylamino)-1-pentylaminolαuinoline S.S- dioxide hvdrochloride

The title compound (350mg) was obtained by a procedure similar to that described in Example 2 using the titie compound of Preparation 4 (500mg, 1.93 mmol), 3-oxotetrahydrothiophene 1 ,1-dioxide (Synthetic Commun., 1983, 13, 269; 259mg, 1.93 mmol) and sodium cyanoborohydride (150mg, 2.88 mmol). Rf 0.80 (SS1). δ (CD₃OD): 1.60-1.80 (6H, m), 2.30 (2H, m), 2.95 (2H, m), 3.30 (5H, m), 4.05 (3H, s), 6.90 (1 H, s), 7.90 (2H, m), 8.80 (1 H, d), 8.90 (1 H, d). m/z 378 (M+H)⁺.

EXAMPLE 4 6-Methoxy-8-r5-(4-tetrahvdrothiopyranylamino)-1-pentylamino1quinoline hvdrochloride

The title compound (500mg) was obtained as a hygroscopic solid by a procedure similar to that described in Example 1 but using 1 molecular equivalent of the quinoline derivative and 0.6 molecular equivalent of sodium cyanoborohydride, i.e. the title compound of Preparation 4 (720mg, 2.76 mmol), 4- tetrahydrothiopyranone (320mg, 2.76 mmol) and sodium cyanoborohydride (104mg, 1.66 mmol) in methanolic hydrogen chloride at pH 6. Rf 0.78 (SS1). δ (CDCI₃) for free base: 2.45 (1 H, tt), 2.62 (6H, m), 3.90 (3H, s), 6.10 (1 H, t), 6.30 (1 H, d), 6.37 (1 H, d), 7.30 (1 H, q), 7.95 (1 H, dd), 8.55 (1 H, d). m/z 360 (M+H)⁺.

EXAMPLE 5 6-Methoxy-8-r5-(4-tetrahvdrothiopyranylamino)-1-pentylamino1αuinoline S- oxide hvdrochloride

Sodium metaperiodate (354mg, 1.65 mmol) was added to a stirred solution of the free base of the title compound of Example 4 (540mg, 1.5 mmol) in 50% aqueous methanol (40ml) and the resulting mixture stirred at room temperature for 1 hour. The methanol was removed by evaporation under reduced pressure and the residual mixture extracted with dichloromethane (3 x 50ml). Evaporation under reduced pressure of the dried (Na₂S0₄), combined extracts provided an oil which was purified by column chromatography on alumina, using methanol:dichloromethane (1 :19) as eluant, then treated with a 1 M solution of hydrogen chloride in ether to furnish the title compound (330mg) as a mixture of cis and trans isomers. Rf 0.40 and 0.50 (SS1). δ (CDCI₃) for free base: 1.50 (6H, m), 1.80-2.10 (4H, bm), 2.60 (4H, m), 3.10 (3H, m), 3.30 (2H, m), 3.90 (3H, s), 6.10 (1 H, bs), 6.15 (1 H, d), 6.20 (1 H, d), 7.30 (1 H, dd), 7.90 (1 H, d), 8.60 (1 H, d). m/z 376 (M+H)⁺.

EXAMPLE 6 6-Methoxy-8-r5-f3-tetrahvdrothiopyranylamino)-1-pentylamino1αuinoline S- oxide hvdrochloride

The title compound (210mg) was obtained by a procedure similar to that described in Example 5, but using ca. 1.25 molecular equivalents of sodium metaperiodate; i.e. the title^' compound of Example 2 (350mg, 0.97 mmol) and sodium metaperiodate (264mg, 1.23 mmol). Rf 0.25 and 0.30 (SS1). δ (CD₃OD): 1.80 (1 OH, s), 2.20-2.90 (4H, bm), 3.10 (3H, m), 3.40 (2H, t), 4.00 (3H, s), 6.90

(1 H, s), 7.95 (2H, m), 8.80 (1 H, d), 8.90 (1H, d). m/z 376 (M+H)⁺.

EXAMPLE 7 5-Bromo-6-methoxy-8-r5-f4-tetrahvdropyranylamino -1-pentylamino1αuinoline hvdrochloride

Tetra-n-butylammonium tribromide (700mg, 1.46 mmol) was added to a stirred, ice-cooled solution of the free base of the title compound of Example 1 (500mg, 1.46 mmol) in dichloromethane (30ml). The cooling bath was removed and the reaction mixture stirred for 0.5 hour, then washed with 1 M aqueous sodium hydroxide solution (10ml). Evaporation under reduced pressure of the dried (Na₂S0 ) organic phase gave an oil which was purified by column chromatography on alumina, using methanol:dichloromethane (1 :99) as eluant, then treated with a 1 M solution of hydrogen chloride in ether to provide the title compound (300mg). Rf 0.55 (SS1 ). δ (CD₃OD): 1.70 (6H, m), 1.80-2.10 (4H, m), 3.10 (2H, t), 3.30 (3H, m), 3.50 (2H, m), 4.00 (2H, dd), 4.10 (3H, s), 7.20 (1 H, s), 7.90 (1 H, dd), 8.90 (1 H, d), 9.00 (1 H, d). m/z 423 (M+H)⁺.

EXAMPLE 8 6-Methoxy-4-methyl-8-r5-(4-tetrahvdrothiopyranylamino)-1-pentylamino1- σuinoline hvdrochloride

The title compound (900mg) was obtained as a yellow solid from 8-(5-amino- 1 -pentylamino)-6-methoxy-4-methylquinoiine (Preparation 5; 1g, 3.7 mmol) by a procedure similar to that described in Example 4. δ (CD₃OD): 1.55-1.95 (9H, m), 2.45 (2H, d), 2.75 (6H, m), 3.10 (2H, m), 3.35 (3H, s), 3.90 (3H, s), 6.40 (1 H, s), 6.55 (1 H, s), 7.48 (1 H, d), 8.08 (1 H, bs). m/z 374 (M+H)⁺.

EXAMPLE 9 6-Methoxy-4-methyl-8-f5- 4-tstrahvdropyranylaminoV1-pentylamino1- quinoline hvdrochloride

The title compound (360mg) was obtained as a yellow solid from the title compound of Preparation 5 (1g, 3.7mmol) and 4-tetrahydropyranone (360mg, 3.6 mmol) by a procedure similar to that described in Example 4. δ (CD₃OD): 1.60- 2.00 (9H, m), 2.00-2.10 (2H, m), 3.10 (2H, t), 3.35 (3H, s), 3.30-3.50 (4H, m), 3.90 (3H, s), 4.00 (2H, m), 6.40 (1 H, bs), 6.60 (1 H, bs), 7.45 (1 H, bs), 8.15 (1 H, bs). m/z 358 (M+H)⁺.

EXAMPLE 10 6-Methoxy-8-f5-f3-tetrahvdrothienylamino -1 -pentylamino1αuinoline hvdrochloride

The title compound (520mg) was obtained as a hygroscopic solid from the title compound of Preparation 4 (720mg, 2.76 mmol) and 3-oxo- tetrahydrothiophene (280mg, 2.76 mmol) by a procedure similar to that described in Example 4. Rf 0.53 (SS1). δ (CDCI₃) for free base: 2.65 (3H, m), 2.85 (2H, t), 3.45 (1 H, m), 3.90 (3H, s), 6.10 (1 H, t), 6.30 (1 H, d), 6.37 (1 H, d), 7.30 (1 H, q), 7.95 (1 H, dd), 8.55 (1 H, d). m/z 346 (M+H)⁺.

EXAMPLE 11 8-r5-(2-D-Galactosylamino)-2-pentylamino1-6-methoxyαuinoline A mixture of 8-(5-amino-2-pentylamino-6-methoxyquinoiine (primaquine;

1.2g, 4.63 mmol), D-galactose (800mg, 4.44 mmol), ethanol (5ml) and water (4ml) was stirred at room temperature for 48 hours. Evaporation under reduced pressure, followed by trituration of the residue with ether, furnished a hygroscopic solid which was dried at 40 °C in vacuo to provide the title compound (800mg) as an off-white solid, δ (CD₃OD): 3.60-3.90 (7H, m), 3.90 (3H, s), 6.35 (1 H, m), 6.50 (1 H, m), 7.40 (1 H, q), 8.05 (1H, dd), 8.55 (1H, d). m/z 422 (M+H)⁺.

EXAMPLE 12 8-r5-(2-D-Glucosylamino)-2-pentylamino.-6-methoxyσuinoline The title compound (800mg) was obtained as a light-brown solid from primaquine (1.2g, 4.63 mmol) and α-D-glucose (800mg, 4.44 mmol) by a procedure similar to that described in Example 11. δ (CD₃OD): 3.10-3.90 (7H, m), 3.90 (3H, s), 6.35 (1 H, m), 6.50 (1 H, m), 7.40 (1 H, q), 8.05 (1 H, dd), 8.55 (1 H, d). m/z 422 (M+H)⁺.

EXAMPLE 13 8-r5-(2-D-MannosylaminoV2-pentylamino1-6-methoxyαuinoline The title compound (1.44g) was obtained as a light-brown solid from primaquine (1.2g, 4.63 mmol) and D-mannose (δOOmg, 4.44 mmol) by a procedure similar to that described in Example 11. δ (CD₃OD): 3.10-3.90 (7H, m), 3.90 (3H, s), 6.35 (1 H, m), 6.50 (1 H, m), 7.40 (1 H, q), δ.05 (1 H, dd), 6.55 (1 H, d). b m/z 422 (M+H)⁺.

EXAMPLE 14 6-Methoxy-6-r5-(2-D-ribosylaminoV2-pentylamino,αuinoline The title compound (670mg) was obtained as a dark-brown solid from 0 primaquine (1.2g, 4.63 mmol) and D-ribose (670mg, 4.43 mmol) by a procedure similar to that described in Example 11. δ (CD₃OD): 3.10-3.90 (6H, m), 3.90 (3H, s), 6.35 (1 H, m), 6.50 (1 H, m), 7.40 (1H, q), δ.05 (1H, dd), δ.55 (1 H, d). m/z 392 (M+H)⁺.

5 EXAMPLE 15

6-Methoxy-δ-r5-(2-tetrahvdrofurylmethylamino)-1-pentylamino1αuinoline hvdrochloride

A mixture of 6-(5-chloropeπtanoylamino)-6-methoxyquinoiine (Preparation 8; 4g) and 2-aminomethyltetrahydrofuran (50ml) was stirred at 100° C for 18 hours. 0 The cool reaction mixture was basified with 1M aqueous sodium hydroxide solution and extraction with dichloromethane effected. Evaporation under reduced pressure of the dried (Na₂S0₄), combined extracts gave an oil which was purified by column chromatography on basic alumina, using an elution gradient of ethyl acetate:dichloromethane (0:100 to 20:80), to afford the intermediate amide 5 (1.2g, 3.52 mmol).

A solution of the amide in dry tetrahydrofuran (10ml) was added, under nitrogen, to an ice-cooled, stirred slurry of aluminium chloride (500mg, 3.75 mmol), a 1 M solution of lithium aluminium hydride in tetrahydrofuran (14ml) and dry tetrahydrofuran (50ml), then stirring continued at this temperature for 2 hours. 0 The reaction mixture was quenched with 1M aqueous sodium hydroxide solution and filtered, then the filtrate extracted with dichloromethane. Evaporation under reduced pressure of the dried (Na₂S0₄), combined extracts, followed by purification of the residue by column chromatography on neutral alumina, using an elution gradient of ethyl acetate:dichloromethane (10:90 to 100:0), gave the free base of the title compound (300mg) as a yellow oil. The hydrochloride salt was obtained from the free base as a brown oil using a 1 M solution of hydrogen chloride in ether (0.9ml). δ (CD₃OD): 3.50-4.20 (3H, m), 3.90 (3H, s), 6.55 (1H, d), 6.70 (1H, m), 7.60 (1H, m), δ.35 (1H, d), 8.63 (1H, d). m/z 344 (M+H)⁺.

EXAMPLE 16 6-Methoxy-8-r5-C3-tetrahvdrofurylamino)-1-pentylamino1αuinoline hvdrochloride

The title compound (1.4g) was obtained as a brown oil from the title compound of Preparation 6 (3.7g, 12.6 mmol) and 3-aminotetrahydrofuran (2.7g, 31 mmol) by a procedure similar to that described in Example 15. δ (CD₃OD): 3.70-4.20 (3H, m), 3.90 (3H, s), 6.50 (1 H, d), 7.60 (1 H, m), 8.35 (1 H, m), 6.63 (1 H, m). m/z 330 (M+H)⁺.

EXAMPLE 17

5.6-Dimethoxy-6-^"5-(4-tetrahvdropyranylamino)-1-pentylamino1quinoline hvdrochloride

Sodium cyanoborohydride (220mg, 3.5 mmol) was added to a stirred mixture of δ-(5-amino-1-pentylamino)-5,6-dimethoxyquinoline (Preparation 3; 1 g, 3.5 mmol), 4-tetrahydropyranone (350mg, 3.5 mmol), a 0.5M solution of hydrogen chloride in methanol (0.5ml) and methanol (20ml), and the resulting mixture stirred at room temperature for 1 δ hours and then evaporated under reduced pressure. The solid residue was thoroughly digested with ethyl acetate, the dried (Na₂S0 ), combined ethyl acetate solutions evaporated under reduced pressure, and the resulting golden brown oil purified by column chromatography on alumina, using ethyl acetate:dichIoromethane (5:95) as eluant, to furnish the free base of the title compound (50mg) as a yellow oil. Treatment of a solution of the free base in 1 - propanol with 1.1 molecular equivalents of a solution of hydrogen chloride in ether produced a bright yellow solid which was crystallised from 2-propanol to afford the title compound (20mg). δ (CDCI₃): 1.25 (2H, m), 1.60 (8H, m), 1.90 (4H, m), 3.30 (4H, t), 3.40 (1 H, q), 3.90 (3H, s), 4.00 (3H, s), 5.60 (1 H, bs), 5.90 (1 H, bs), 6.40 (1 H, s), 7.30 (1 H, m), 8.25 (1 H, dd), δ.45 (1 H, d). m/z 374 (M+H)⁺.

EXAMPLE 18 6-Methoxy-δ-r5-(4-tetrahvdrothiopyranylamino)-2-pentylaminolquinoline hvdrochloride

A mixture of primaquine (1.53g, 5.92 mmol), 4-tetrahydrothiopyranone (340mg, 2.96 mmol), sodium cyanoborohydride (111 mg, 1.76 mmol), a 50% solution of concentrated hydrochloric acid in methanol (0.3δml) and methanol (2.6ml) was stirred at room temperature for 15 hours, then evaporated under reduced pressure. The resulting viscous reddish-brown oil (ca. 2g) was dissolved in ethyl acetate (1.5ml) and purified by column chromatography on basic alumina, using an elution gradient of methanol:ethyl acetate (0:100 to 5:95), to give the free base of the title compound (δ94mg) as a brown oil. Treatment of a solution of the free base in dry ether (10ml) with 1.1 molecular equivalents of a solution of hydrogen chloride in ether provided the title compound (δ70mg) as an orange, slightly hygroscopic solid. Rf 0.δ6 (SS2). δ (CD₃OD): 1.33 (3H, d), 1.70-2.50 (8H, m), 2.75 (4H, m), 2.80-3.05 (1 H, m), 3.25 (2H, t), 3.75 (1 H, tq), 3.90 (3H, s), 6.85 (1 H, s), 7.90 (1 H, dd), 8.70-δ.δO (2H, dd). m/z 360 (M+H)⁺.

EXAMPLE 19 6-Methoxy-8-r4-(4-tetrahvdropyranylamino -1-butylamino1quinoline hvdrochloride

The title compound was obtained from its free base (340mg) as a hygroscopic solid by a procedure similar to that described in Example 17 but using ca. 1.1 molecular equivalents of both the ketone and sodium cyanoborohydride; i.e. the title compound of Preparation 6 (700mg, 2.9 mmol), 4-tetrahydropyranone (320mg, 3.19 mmol) and sodium cyanoborohydride (185mg, 3.19 mmol), and ethyl acetate as the eluant for chromatographic purification of the free base of the titie compound. Rf 0.65 (SS3), 0.60 (SS4). δ (CDCI₃) for free base: 1.60 (2H, m), 1.90 (2H, bd), 3.35 (4H, m), 3.90 (3H, s), 3.95 (2H, bd), 6.60 (1 H, d), 6.90 (1H, d), 7.35 (1 H, q), 7.95 (1 H, dd), 6.55 (1H, d). m/z 330 (M+H)⁺.

EXAMPLE 20 6-Methoxy-8-r2-(4-tetrahvdropyranylamino)ethylaminolquinoline hvdrochloride

The title compound and its free base (370mg) were obtained by a procedure similar to that described in Example 19 using the title compound of Preparation 7 (800mg, 3.7 mmol), 4-tetrahydropyranone (400mg, 4.07 mmol) and sodium cyanoborohydride (250mg, 4.07 mmol). Rf 0.60 (SS3), 0.65 (SS4). δ (CDCI₃) for free base: 1.50 (2H, m), 1.90 (2H, bd), 2.80 (1 H, m), 3.10 (2H, t), 3.45 (4H, m), 3.90 (3H, s), 3.95 (2H, bd), 6.30 (1H, t), 6.37 (2H, dd), 7.30 (1 H, q), 7.95 (1 H, dd), 8.55 (1 H, d). m/z 302 (M+H)⁺.

EXAMPLE 21 6-Methoxy-8-r5-f3-tetrahvdrothienylamino)-1-pentylamino1quinoline S-oxide The title compound (1δmg) was obtained as an oil by a procedure similar to that described in Example 5, but with stirring of the reaction mixture for 24 hours and using methanol:ethyl acetate (1 :9) as the eluant for chromatographic purification, from the title compound of Example 10 (146mg, 0.42 mmol), sodium periodate (100mg, 0.46 mmol) and 50% aqueous methanol (20ml). Rf 0.25 (SS1). δ (CDCI₃): 2.55-3.35 (11 H, m), 3.90 (3H, s), 6.10 (1 H, t), 6.30 (1 H, d), 6.40 (1 H, d), 7.35 (1 H, q), 7.95 (1 H, dd), δ.55 (1 H, d). m/z 362 (M+H)⁺. EXAMPLE 22 8-^'4-(2-D-MannosylaminoV1 -butylamino1-6-methoχyquinoline The title compound (150mg) was obtained as a pink crystalline solid from the title compound of Preparation 6 (300mg, 1.22 mmol) and D-mannose (230mg, 1.27 mmol) by a procedure similar to that described in Example 11. Rf 0.30 (SS1). δ (CD₃OD): 1.60-1.90 (4H, m), 2.60-2.70 (2H, m), 3.00-3.30 (4H, m), 3.50- 3.60 (6H, m), 3.90 (3H, s), 4.10 (1 H, bs), 6.30 (1 H, s), 6.50 (1 H, s), 7.30 (1 H, dd), δ.00 (1 H, d), 8.50 (1 H, s). m/z 40δ (M+H)⁺.

EXAMPLE 23 6-Methoxy-δ-f6-(4-tetrahvdropyranylamino)-1-hexylamino1ouinoline hvdrochloride A stirred suspension of platinum oxide (0.5g) in ethanol (75ml) was prehydrogenated at 207kPa (30psi) and room temperature for 0.5 hour, then a solution of 8-(6-amino-1-hexylamino)-6-methoxyquinoline (Preparation 10; 5.0g, 1δ.3 mmol) and 4-tetrahydropyranone (2.17g, 21.7 mmol) in ethanol (125ml) was added and the hydrogenation continued under the same conditions for 2 days. Filtration of the resulting mixture, followed by evaporation under reduced pressure of the filtrate, gave the crude free base of the title compound (6.2g) as a deep red oil. A portion (5.0g) of this oil was dissolved in the minimum volume of dry 1- propanol, then the resulting solution stirred whilst a 1 M solution of hydrogen chloride in ether (17ml) was added. After a further 10 minutes, the mixture was treated with dry ether until precipitation of the required hydrochloride salt was effected. The precipitate was extracted into water and the resulting aqueous solution freeze-dried to afford the title compound (4.2g). δ (CDCI₃): 1.40-2.20 (12H, m), 2.90 (2H, m) 3.20 (3H, m), 3.40 (2H, bt), 3.90 (3H, s), 4.05 (2H, m), 6.40 (2H, m), 7.50 (1 H, m), δ.20 (1 H, m), 6.60 (1 H, m), 9.60 (2H, m). m/z 356 (M+H)⁺. EXAMPLE 24 6-Methoxy-8-r7-(4-tetrahvdropyranylamino)-1-heptylamino1quinoline hvdrochloride

The title compound (4.3g) was obtained as a brown solid from 8-(7-amino-1 - heptylamino)-6-methoxyquinoline (Preparation 12; 3.85g, 13.4 mmol) and 4- tetrahydropyranone (1.6g, 16 mmol), by a procedure similar to that described in Example 23, except that the hydrogenation was conducted for 3 hours and the hydrochloride salt was isolated by trituration of the initially obtained gum with dry ether and immediate drying in vacuo over phosphorous pentoxide. δ (CDCI₃): 1.20-1.60 (10H, m), 1.60-2.20 (4H, m), 2.δ0 (2H, m), 3.2 (3H, m), 3.70 (2H, m), 3.90 (3H, s), 4.05 (2H, m), 6.60 (2H, m), 7.70 (1 H, dd), 6.50 (1H, dd), δ.70 (1 H, dd), 9.40-9.60 (2H, 2 x s). m/z 372 (M+H)⁺.

EXAMPLE 25 6-Methoxy-δ-rδ-f4-tetrahvdropyranylamino -1-octylamino1quinoline hvdrochloride

The title compound (4.0g) was obtained as a dark brown solid from δ-(δ- amino-1-octylamino)-6-methoxyquinoline (Preparation 15; 4.55g, 15 mmol) and 4- tetrahyd ropy ran one (1.δ1g, 18.1 mmol), by a procedure similar to that described in Example 24. δ (CDCI₃): 1.20-1.60 (12H, m), 1.60-2.20 (4H, m), 2.90 (2H, bm), 3.20 (3H, m), 3.40 (2H, m), 3.60 (3H, s), 4.00 (2H, dt), 6.40 (2H, 2 x s), 7.40 (1H, dd), 8.00 (1 H, d), 8.50 (1H, d), 9.40-9.80 (2H, 2 x bs). m/z 386 (M+H)⁺.

EXAMPLE 26 6-Methoxy-5-methyl-8r5-(4-tetrahvdropyranylamino)-1-pentylamino1quinoline pamoate The crude free base of the title compound was obtained as a brown oil from

8-(5-amino-1-pentylamino)-6-methoxy-5-methylquinoIine (Preparation 17; 1.0 g, 3.7 mmol) and 4-tetrahydropyranone (0.60 g, 6.0 mmol), by a procedure similar to that described in Example 23, except that the hydrogenation was conducted at 133 kPa (20 psi) and for 16 hours. It was purified by column chromatography on alumina, using methanokdichloromethane (1 :99) as eluant, and then converted to the hydrochloride salt using a 1 M solution of hydrogen chloride in ether. The resulting red oil was dissolved in water (10 ml) and the solution treated with a solution of disodium pamoate hydrate (1.2 g) in water (15 ml). The orange precipitate was collected by filtration, washed with water and dried ]n vacuo to give the title compound (2.7 g). δ(CDCI₃) for free base: 2.35(3H,s), 2.δ5(4H,m), 3.40(4H,td), 3.85(1 H,m), 3.95(3H,s), 4.15(2H,dt), 6.50(1 H,t), 6.41 (1 H,s), 7.35(1 H,q), 8.12(1 H,dd), 8.55(1 H,d). m/z 358 (M+H)⁺.

PREPARATIQN 1 8-Amino-5.6-dimethoxyouinoline Obtained essentially by the procedure described in J. Med. Chem., 1962, 25.

964.

PREPARATION 2 5.6-Dimethoxy-δ-r5-(N-phthalimido -1 -pentylaminolquinoline A mixture of the title compound of Preparation 1 (5g, 24.5 mmol), N-(5- bromo-1-pentyl)phthalimide (J.Chem.Soc, 1929, 2959; 8.5g, 24.5 mmol) and triethylamine (2.5g, 24.5 mmol), under nitrogen, was stirred at 150° C for 6 hours and then at room temperature for 16 hours. The resulting solid mixture was dissolved in dichloromethane and this solution washed successively with dilute hydrochloric acid and water, dried (Na₂S0₄), then evaporated under reduced pressure to give a golden brown oil. Sonication of the oil with a mixture of methanol and 2-propanol provided a yellow solid which was collected, washed with methanol and dried in vacuo. to afford the title compound (δg). δ (CDCI₃): 1.25 (2H, m), 1.80 (4H, m), 3.25 (2H, m), 3.70 (2H, t), 3.90 (3H, s), 4.00 (3H, s), 5.90 (1 H, bs), 6.40 (1 H, s), 7.30 (1 H, m), 7.80 (4H, mm), 8.25 (1 H, dd), 8.45 (1 H, d). m/z 420 (M+H)⁺.

PREPARATION 3 8-(5-Amino-1-pentylamino)-5.6-dimethoxyquinoline A mixture of the title compound of Preparation 2 (δg, 19 mmol), hydrazine hydrate (3ml, 0.10 mol) and ethanol (100ml) was stirred under reflux for 3 hours and then at room temperature for 16 hours. The reaction mixture was allowed to cool and filtered, then the filtrate evaporated under reduced pressure. The resulting residue was basified to pH 11 using aqueous sodium hydroxide solution and the mixture extracted with ether. Evaporation under reduced pressure of the dried (Na₂S0₄), combined extracts furnished the title compound (4.9g) as a yellowish brown oil. δ (CDCI₃): 1.25 (2H, m), 1.80 (4H, m), 3.25 (2H, m), 3.70 (2H, t), 3.90 (3H, s), 4.00 (3H, s), 5.60 (2H, bs), 5.90 (1 H, bs), 6.40 (1 H, s), 7.30 (1 H, m), 8.25 (1 H, dd), 8.45 (1 H, d). m/z 290 (M+Hf.

PREPARATION 4 8-f5-Amino-1-pentylamino)-6-methoxyouinoline The title compound (J.Amer.Chem.Soc, 1946, 68, 1536) was obtained from 6-methoxy-8-nitroquinoline by analogy with the synthetic procedures described above for producing the title compound of Preparation 3.

PREPARATION 5 δ-(5-Amino-1-pentylamino)-6-methoxy-4-methylouinoline The title compound was obtained from 8-amino-6-methoxy-4-methylquinoline

(prepared from 4-amino-3-nitroanisole using the procedure described in J. Med. Chem., 1982, 25, 964) by analogy with Preparation 3 as a yellow oil. m/z 274 (M+H)⁺.

PREPARATION 6

8-(4-Amino-1-butylamino)-6-methoxyquinoline The title compound (J. Chem. Soc, 1934, 1524) was obtained by analogy with Preparation 4.

PREPARATION 7

3-(2-Aminoethylamino)-6-methoxyquinoline The title compound (J. Chem. Soc, 1929, 2959) was obtained by analogy with Preparation 4. PREPARATION δ 6-f5-Chloropentanoylamino)-6-methoxyouinoline A mixture of δ-amino-6-methoxyquinoline (21.8g, 0.125 mol), 5-chlorovaleryl chloride (8ml, 0.062 mol) and anhydrous toluene (90ml) was stirred at 100° C for 1 hour. The cool reaction mixture was filtered, then the filtrate washed successively with 10% aqueous acetic acid solution and 10% aqueous sodium carbonate solution, dried (Na₂S0₄) and evaporated under reduced pressure. Crystallisation of the resulting brown solid from dichloromethane:ether afforded the title compound (6g) as a light brown solid, δ (CDCI₃): 1.60-2.00 (2H, m), 2.60 (2H, t), 3.60 (2H, t), 3.82 (3H, s), 6.80 (1H, d), 7.40 (1H, m), 8.05 (1H, d), 8.53 (1H, d), 8.63 (1 H, d), 9.80 (1 H, bs). m/z 294 (M+H)⁺.

PREPARATION 9

8-(5-Cvano-1-pentylamino)-6-methoxyQuinoline

A mixture of δ-amino-6-methoxyquinoline (5.0g, 28.7 mmol), 1-bromo-5- cyanopentane (5.0g, 28.5 mmol) and triethylamine (2.3ml) was stirred at 100°C for

12 hours. The cool reaction mixture was evaporated under reduced pressure and the resulting dark tar dissolved in dichloromethane (50ml), then this solution was washed with saturated brine (25ml) and evaporated under reduced pressure to give a solid. The crude product was purified by column chromatography on silica gel, using dichloromethane as eluant, to provide the title compound (4.65g) as a reddish-orange solid. Rf 0.80 (SS5). δ (CDCI₃): 1.50-1.90 (6H, m), 2.35 (2H, t), 3.30 (2H, dd), 3.85 (3H, s), 6.00 (1 H, bs), 6.20 (1 H, dd), 6.30 (1 H, dd), 7.30 (1 H, dd), 7.80 (1 H, dd), 8.50 (1H, dd). m/z 270 (M+H)⁺. PREPARATION 10 δ-(6-Amino-1-hexylamino)-6-methoxyquinoline A solution of lithium aluminium hydride in tetrahydrofuran (1 ; 54ml, 54 mmol) was added under nitrogen to stirred, dry tetrahydrofuran (50ml). The resulting solution was cooled to -5°C to 0°C, then a solution of the title compound of Preparation 9 (4.65g, 17.3 mmol) in dry tetrahydrofuran (100ml) added dropwise whilst maintaining the temperature below 5°C. The reaction mixture was stirred for a further 0.5 hour and then quenched by the sequential, dropwise addition of a mixture of water (2ml) and tetrahydrofuran (20ml), 15% aqueous sodium hydroxide solution (2ml) and water (6ml). The resulting mixture was stirred for 0.5 hour at room temperature and filtered, then the filtrate evaporated under reduced pressure to provide the title compound (ca^ 100% yield) as a deep reddish oily gum of sufficient purity to be progressed to the final stage of the reaction sequence (Example 23). δ (CDCI₃): 1.20-1.60 (8H, m), 2.70 (2H, t), 3.30 (2H, m), 3.90 (3H, s), 6.30 (2H, dd), 7.30 (1 H, dd), 7.90 (1 H, dd), 8.50 (1 H, dd). m/z 274 (M+H)⁺.

PREPARATION 11

8-(6-Cvano-1-hexylamino,-6-methoxyquinoline The title compound (56% yield) was obtained as a reddish-orange solid, by a procedure similar to that described in Preparation 9, using 1-bromo-6- cyanohexane as the appropriate nitrile. δ (CDCI₃): 1.40-1.90 (8H, m), 2.40 (2H, t), 3.30 (2H, dd), 3.90 (3H, s), 6.00 (1 H, bs), 6.30 (1 H, dd), 6.40 (1 H, dd), 7.30 (1 H, dd), 7.90 (1 H, dd), 8.60 (1 H, dd). m/z 284 (M+H)⁺. PREPARATION 12 8-f7-Amino-1-heptylamino)-6-methoxyouinoline The title compound (ca. 99% yield) was obtained as a reddish oily gum of sufficient purity to be progressed to the final stage of the reaction sequence (Example 24) from the title compound of Preparation 11 , by a procedure similar to that described in Preparation 10. δ (CDCI₃): 1.20-1.50 (10H, m), 2.70 (2H, t), 3.20 (2H, t), 3.80 (3H, s), 6.30 (1 H, dd), 6.40 (1 H, dd), 7.30 (1 H, dd), 7.90 (1 H, dd), 8.60 (1 H, dd). m/z 288 (M+H)⁺.

PREPARATION 13 1 -Bromo-7-cvanoheptane A stirred mixture of 8-bromooctanoic acid (11.Oδg, 49.7 mmol) and thionyl chloride (4.35ml, 59.6 mmol) was heated under reflux for 1 hour, then the excess thionyl chloride removed by evaporation under reduced pressure. The resulting residue was added dropwise to stirred, ice-cooled 0.880 aqueous ammonia solution (70ml) and the resulting solid collected by filtration, washed with 0.860 aqueous ammonia solution and dried in vacuo over phosphorous pentoxide to furnish 8-bromooctanamide (10.92g).

A stirred mixture of the intermediate amide and thionyl chloride (9.0ml, 0.123 mol) was heated under reflux for 4 hours, then the excess thionyl chloride removed by evaporation under reduced pressure to afford the title compound (9.67g). δ (CDCI₃): 1.20-1.50 (6H, m), 1.50-1.60 (2H, m), 1.70-1.80 (2H, m), 2.40 (2H, t), 3.50 (2H, t). m/z 205 (M+H)⁺. PREPARATION 14 8-(7-Cvano-1-heptylamino)-6-methoxyouinoline The titie compound (49% yield) was obtained as a dark reddish gum, by a procedure similar to that described in Preparation 9, using the title compound of Preparation 13 as the appropriate nitrile. Rf 0.80 (SS5). δ (CDCI₃): 1.40-1.80 (10H, m), 2.30 (2H, t), 3.30 (2H, dd), 3.80 (3H, s), 6.10 (1H, bs), 6.30 (1 H, dd), 6.40 (1 H, dd), 7.40 (1 H, dd), 7.90 (1 H, dd), 8.60 (1 H, dd). m z 298 (M+H)⁺.

PREPARATION 15 8-(8-Amino-1-octylamino -6-methoxyquinoline The title compound (85% yield) was obtained as a reddish-brown oily gum of sufficient purity to be progressed to the final stage of the reaction sequence (Example 25) from the title compound of Preparation 14, by a procedure similar to that described in Preparation 10. δ (CDCI₃): 1.30-1.60 (12H, m), 2.50 (2H, t), 3.20 (2H, m), 3.80 (3H, s), 6.20 (1 H, dd), 6.30 (1 H, dd), 7.30 (1 H, dd), 7.80 (1 H, dd), 8.40 (1 H, dd). m z 302 (M+H)⁺.

PREPARATION 16

8-(4-Cvano-1-butylamino)-6-methoxy-5-methylquinoline

The title compound (57% yield) was obtained by a procedure similar to that described in Preparation 9, using 8-amino-6-methoxy-5-methylquinoline (J. Amer. Chem. Soc, 1946, 68, 1551 ; prepared from 4-amino-2-methyI-5-nitroanisole via 6- methoxy-5-methyl-8-nitroquinoiine by analogy with the procedure described in J. Med. Chem., 1982, 25, 964) and 1-bromo-4-cyanobutane. δ(CDCI₃): 1.80- 2.05(4H,m), 2.38(3H,s), 2.45(2H,t), 3.40(2H,m), 3.95(3H,s), 6.20(1 H,bs), 6.45(1 H,s), 7.40(1 H,q), 8.20(1 H,dd), 8.60(1 H,d). m/z 270 (M+H)⁺. PREPARATION 17 8-(5-Amino-1-pentviamino)-6-methoxy-5-methylquinoline

The title compound (50% yield) was obtained from the title compound of Preparation 16, by a procedure similar to that described in Preparation 10. δ(CDCI₃): 2.35(3H,s), 3.95(3H,s), 6.10(1 H,t), 6.42(1 H,s), 7.35(1 H,q), 8.10(1 H,dd), δ.55(1 H,d). m/z 274 (M+H)⁺.

Biolooical activity

The following Table illustrates the in vivo anticoccidial activities in poultry for a range of the compounds of the invention, determined by the test methods described on pages 14 to 15. ED₉₅ is the concentration of drug in parts per million (ppm) in the meal diet required to achieve 95% lesion control of the particular Eimeria species identified.

TABLE

EXAMPLE ED₉₅ NUMBER

E. tenella = E. acervulina

1 12.5 12.5

9 12.5 25

15 12.5 25

16 50 100

20 12.5 12.5

Claims

1. A compound of formula (I):

a non-toxic salt thereof, or a non-toxic solvate of either entity; wherein A is C₂-Cι₀ alkylene, C₄-Cβ alkenylene, C -C₆ alkynylene or C₅-C₇ cycloalkylene;

B is a direct link or C-ι-C₆ alkylene;

W is O, S, SO or S0₂;

R¹ is OH, C1-C4 alkoxy or C1-C4 alkyl; R² is H; halo; OH; C C₄ alkoxy; C1-C4 alkylamino; di C₁-C₄ alkylamino;

C₂-C₄ alkenyl optionally substituted with phenyl, C0₂(CrC₄ alkyl), CN or CONH₂; or phenyl or phenoxy optionally substituted with one or two substituents selected from C.-C₄ alkyl, C₁-C₄ alkoxy, halo, CF₃ and amino;

R³ is H; halo; C₂-C₄ alkenyl optionally substituted with phenyl, C0₂(C

C₄ alkyl), CN or CONH₂; phenyl optionally substituted with one or two substituents selected from C₁-C4 alkyl, C1-C4 alkoxy, halo, CF₃ and amino; thienyl; furyl or pyridyl;

R⁴ is H or CrC₄ alkyl;

R⁵ is H; C C₄ alkyl; Cι-C₄ alkoxy; halo; C₂-C₄ alkenyl optionally substituted with phenyl, C0₂(C C₄ alkyl), CN or CONH_2; phenyl or phenoxy optionally substituted with one or two substituents selected from C C alkyl, Cι-C₄ alkoxy, halo, CF₃ and amino; thienyl; furyl or pyridyl; R⁶ is H or C C₄ alkyl;

R⁷ is H or C C₄ alkoxy; m is 1 , 2 or 3; n is 0, 1 , 2, 3 or 4; and p is 0 or 1.

2. A compound according to claim 1 wherein A is C₂-Cιo alkylene; R¹ is OH; R² and R³ are H; R⁴ is H or C C alkyl; R⁵ is H, C C₄ alkyl, Cι-C₄ alkoxy or halo; R⁶ is C1-C4 alkyl and R⁷ is H.

3. A compound according to claim 2 wherein A is C₂-C₈ alkylene; B is a direct link or methylene; R⁴ is H or methyl; R⁵ is H, methyl, methoxy or bromo; R⁶ is methyl; m is 2 or 3 and n is 0, 2 or 3.

4. A compound according to claim 3 wherein A is C₄-C₅ alkylene; W is O, S or SO and R⁵ is H or bromo.

5. A compound according to claim 4 wherein A is (CH₂)₅; W is O; n is 0 and p is 0. 6. A compound according to claim 5 wherein the compound of formula (I) is selected from

6-methoxy-8-[5-(4-tetrahydropyranylamino)-1-pentylamino]quinoline; 5-bromo-6-methoxy-8-[5-(4-tetrahydropyranylamino)-1-pentylamino]- quinoline; 6-methoxy-4-methyl-8-[5-(4-tetrahydropyranylamino)-1 -pentylamino]- quinoiine;

6-methoxy-8-[5-(2-tetrahydrofurylmethylamino)-1-pentylamino]quinoiine; and 6-methoxy-8-[5-(3-tetrahydrofurylamino)-1-pentylamino]quinoline.

7. A composition for treating animals comprising a compound of formula (I), or a non-toxic salt thereof, or a non-toxic solvate of either entity, together with a suitable diluent or carrier.

8. A composition according to claim 7 in the form of an oral, injectable, implant, pour-on or spot-on formulation, or in the form of a concentrate, premix or supplement for incorporation with the animals' normal feed or drinking water.

9. A composition according to claims 7 and 8 wherein the animals are poultry, cattle or sheep.

10. A compound of formula (I), or a non-toxic salt thereof, or a non-toxic solvate of either entity, or a composition containing any of the foregoing, according to any one of claims 1 to 9, for use in the treatment or prevention of protozoal diseases, or in performance enhancement, in animals.

11. The use according to claim 10 wherein the disease is coccidiosis.

12. The use according to claims 10 and 11 wherein the animals are poultry, cattle or sheep.

13. The use of a compound of formula (I), or a non-toxic salt thereof, or a non¬ toxic solvate of either entity, or a composition containing any of the foregoing, according to any one of claims 1 to 9, for the manufacture of a medicament for the treatment or prevention of protozoal diseases, or for performance enhancement, in animals.

14. The use according to claim 13 wherein the disease is coccidiosis.

15. The use according to claims 13 and 14 wherein the animals are poultry, cattle or sheep.

16. A compound of formula (II):

wherein A, R^2, R³, R⁴, R⁵, R⁶ and R⁷ are as previously defined for formula (I) in ciaim 1.

17. A compound of formula (VIII):

wherein A¹ is d-Cg alkylene, C₃-C₅ alkenylene or C₃-C5 alkynylene, and B, W, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, m, n and p are as previously defined for formula (I) in claim 1.

18. A method of treating animals to cure or prevent a protozoal disease, or to enhance performance, which comprises treating said animals with an effective amount of a compound of formula (I), or a non-toxic salt thereof, or a non-toxic solvate of either entity, or a composition containing any of the foregoing, according to any one of claims 1 to 9.

19. A method according to claim 1δ wherein the disease is coccidiosis.

20. A method according to claims 1 δ and 19 wherein the animals are poultry, cattle or sheep.