WO2000021949A1

WO2000021949A1 - Quinolones as t-rna synthetase inhibitors and antibacterial agents

Info

Publication number: WO2000021949A1
Application number: PCT/EP1999/007760
Authority: WO
Inventors: John Michael Berge; John Stephen Elder; Andrew Keith Forrest; Richard Lewis Jarvest
Original assignee: Smithkline Beecham Plc
Priority date: 1998-10-12
Filing date: 1999-10-05
Publication date: 2000-04-20
Also published as: GB9822241D0; AU6339499A; AR024219A1

Abstract

Compounds of formula (I), in which: R1 is aryl or heteroaryl; R2 is hydrogen, C¿(1-6)?alkyl, arylC(1-4)alkyl, arylC(2-4)alkenyl or C(1-6)alkylcarbonyl; R?3¿ is selected from halo, cyano, hydroxy, (C¿1-6)?alkyl (optionally substituted by halo, hydroxy, amino, carboxy or (C1-6)alkoxycarbonyl), (C3-7)cycloalkyl, C(1-6)alkoxy, amino, mono- or di-(C1-6)alkylamino, acylamino, carboxy, (C1-6)alkoxycarbonyl, carboxy(C1-6)alkyloxy, (C1-6)alkylthio, (C1-6)alkylsulphinyl, (C1-6)alkylsulphonyl, sulphamoyl, mono- and di-(C1-6)alkylsulphonyl, carbamoyl, mono- and di-(C1-6)alkylcarbamoyl, and heterocyclyl; m is 0 or an integer from 1 to 3; R?4¿ and a substituent on R1 are linked to form a saturated bridge comprising one or two carbon atoms and a heteroatom selected from O and NR5; R5 is hydrogen or C¿(1-6)?alkyl; Y is a linker group having from 2 to 6 methylene groups in a straight chain and in which one or more alkylene groups may have one or more C(1-6) alkyl substituents and which substituents may be linked to form a C2 or C3 alkylene bridge; Z is NH or O; and salts thereof, preferably pharmaceutically acceptable salts; are inhibitors of Saureus methionyl tRNA synthetase and thereof of use in therapy as antibacterial agents.

Description

QUINOLONES AS T-RNA SYNTHETASE INHIBITORS AND ANTIBACTERIAL AGENTS

The present invention relates to novel 2-(NH- or O- substituted) quinolones which are inhibitors of methionyl t-RNA synthetase (MRS), processes for their preparation and their use in therapy as anti-bacterial agents. t-RNA synthetases are involved in protein biosynthesis so that inhibition thereof may be expected to lead to a cessation of cell growth. Thus, for instance, the compound mupirocin, produced by the organism Pseudomonas fluorescens, is an anti-bacterial agent and is used as the active ingredient in the product Bactroban, marketed by SmithKline Beecham. Mupirocin has been shown to be an inhibitor of the isoleucyl t- RNA synthetase. Each t-RNA synthetases represents a separate target for drug discovery. t-RNA synthetase inhibitors which are selective for bacterial cells over mammalian cells are of considerable therapeutic interest as they have the potential to be used as anti-bacterial agents. The sequence of the t-RNA synthetase genes in organisms such as S a reus have recently been determined, see for instance European Patent application no 97300317.1 (SmithKline Beecham, S aureus MRS), thereby assisting the process of identifying inhibitors.

Various classes of 2-aminoquinolones have been previously described, for instance WO 96/060884 (as anti-arrhythmic agents) and EP 0143630, and US 4005205 (as H-2 histamine receptor antagonists). International application PCT/EP99/02648 (SmithKline Beecham, filing date 19 April 1999) describes a novel class of 2-(NH- or O- substituted) quinolones which are potent inhibitors of methionyl t-RNA synthetase. We have now found a further class of 2-(NH- or O- substituted) quinolones which are potent inhibitors of methionyl t-RNA synthetase. Accordingly, the present invention provides compounds of the formula (I):

(I) in which:

R! is aryl or heteroaryl;

R2 is hydrogen, C(i_6)alkyl, arylC(i_4)alkyl, arylC(2_4)alkenyl or C(i_6)alkylcarbonyl; R3 is selected from halo, cyano, hydroxy, (Cι -6)alkyl (optionally substituted by halo, hydroxy, amino, carboxy or (Ci -6)alkoxycarbonyl), (C3-7)cycloalkyl, C( g)alkoxy, amino, mono- or di-(Cι-6)alkylamino, acylamino, carboxy, (Cι-6)alkoxycarbonyl, carboxy(Cι-6)alkyloxy, (Cι-6)alkylthio, (Cι-6)alkylsulphinyl, (Cι -6)alkylsulphonyl, sulphamoyl, mono- and di-(Cι -6)alkylsulphamoyl, carbamoyl, mono- and di-(Cι -6)alkylcarbamoyl, and heterocyclyl; m is 0 or an integer from 1 to 3;

R4 and a substituent on R* are linked to form a saturated bridge comprising one or two carbon atoms and a heteroatom selected from O and NR^;

R5 is hydrogen or C(i.g)alkyl;

Y is a linker group having from 2 to 6 methylene groups in a straight chain and in which one or more alkylene groups may have one or more Cπ -6) ^kyl substituents and which substituents may be linked to form a C2 or C3 alkylene bridge;

Z is NH or O; and salts thereof, preferably pharmaceutically acceptable salts thereof.

Compounds of formula (I) are inhibitors of S aureus methionyl tRNA synthetase.

A preferred group of compounds of formula (I) are those in which R! is phenyl, that is compounds of formula (LA):

(IA) in which R^, R3_{; m;} γ_? and Z are as hereinbefore defined;

R⁴ and R⁶ form a bridge X(CH₂)p where X is O or NR⁵ and p is 1 or 2 ;

R7 is selected from halo, cyano, hydroxy, (Ci -6)alkyl (optionally substituted by halo, hydroxy, amino, carboxy or (Ci -6)alkoxycarbonyl), (C3-7)cycloalkyl, C(i_6)alkoxy, amino, mono- or di-(Cι -6)alkylamino, acylamino, carboxy, (Cι -6)alkoxycarbonyl, carboxy(Cι-6)alkyloxy, (Cι-6)alkylthio, (Cι-6)alkylsulphinyl, (Ci"6)alkylsulphonyl, sulphamoyl, mono- and di-(Cι-6)alkylsulphamoyl, carbamoyl, mono- and di-(Cι -6)alkylcarbamoyl, and heterocyclyl; and n is O, 1, 2 or 3.

Preferably, the heteroatom X is attached to the phenyl ring. Representative examples of the R6/R4 bridge include -OCH2-, -O(CH2)2^_> -O(CH₂)CH(CH₃)- and -NH(CH₂)2--

Representative values of R^ include halo, for instance chloro, bromo, iodo, alkoxy, for instance methoxy and alkyl, for instance ethyl. A preferred substitution pattern is 3,5-; for instance 3,5-dihalo-, 3-alkyl, 5-halo-, 3-halo, 5-alkyl-, 3-alkoxy, 5- halo or 3-halo, 5-alkoxy; for example 3,5-dichloro-, 3-iodo, 5-chloro-, 3-ethyl, 5-bromo- , 3-bromo, 5-ethoxy.

Representative examples of R^ include hydrogen.

Preferably, n is 2, 3 or 4. Representative examples of Y include (CH2)n where n is 3.

Preferably, Z is NH.

Salts may be formed from inorganic and organic acids. Representative examples of suitable inorganic and organic acids from which pharmaceutically acceptable salts of compounds of formula (I) may be formed include maleic, fumaric, benzoic, ascorbic, pamoic, succinic, bis-methylenesalicylic, methanesulfonic, ethanedisulfonic, acetic, propionic, tartaric, salicylic, citric, gluconic, aspartic, stearic, palmitic, itaconic, glycolic, p-aminobenzoic, glutamic, benzenesulfonic, hydrochloric, hydrobromic, sulfuric, cyclohexylsulfamic, phosphoric and nitric acids. When used herein, the term "alkyl" and similar terms such as "alkoxy" includes all straight chain and branched isomers. Representative examples thereof include methyl, ethyl, n-propyl, wo-propyl, n-butyl, sec-butyl, wo-butyl, t-butyl, n-pentyl and n-hexyl.

Preferred substituents for an alkyl group include, for example, and unless otherwise defined, halogen, cyano, azido, nitro, carboxy, (C ό^koxycarbonyl, carbamoyl, mono- or di-(Cι .6)^lkyl^cart»amoyl, sulpho, sulphamoyl, mono- or di-(Cι. 6)alkylsulphamoyl, amino, mono- or di-(Cι_6)alkylamino, acylamino, ureido,

(Cι_6)alkoxycarbonylamino, 2,2,2-trichloroethoxycarbonylamino, aryl, heterocyclyl, hydroxy, (Cj_6)alkoxy, acyloxy, oxo, acyl, 2-thienoyl, (Cι_6)alkylthio, (Cι_6)alkylsulphinyl, (Cμ6)alkylsulphonyl, hydroxyimino, (Cι_6)alkoxyimino, hydrazino, hydrazono, benzohydroximoyl, guanidino, a idino and iminoalkylamino. When used herein, the term "aryl" includes, unless otherwise defined, phenyl or naphthyl optionally substituted with up to five, preferably up to three substituents.

Preferred substituents for an aryl group include, for example, and unless otherwise defined, halogen, cyano, (Cι -6)alkyl, (C3-7)cycloalkyl, (Cι-6)alkoxy, halo(Cι -5)alkyl, hydroxy, amino, mono- or di-(Cι -6)alkylamino, acylamino, nitro, carboxy, (Cι -6)alkoxycarbonyl, (Cι -6)alkenyloxycarbonyl,

(C 1 -6)alkoxycarbonyl(C \ -6)alky 1, carboxy (C \ -6)alkyl, (C \ -6)alkylcarbonyloxy , carboxy (C \ -6)alkyloxy , (C \ -6)alkoxycarbonyl(C \ -6)alkoxy , (C 1 -6)alkylthio, (Cι -6)alkylsulphinyl, (Cj-^alkylsulphonyl, sulphamoyl, mono- and di-(Cj-6)- alkylsulphamoyl, carbamoyl, mono- and di-(Cι-6)alkylcarbamoyl, and heterocyclyl. When used herein, the term "heteroaryl" includes single or fused rings comprising up to four hetero-atoms in the ring selected from oxygen, nitrogen and sulphur and optionally substituted with up to three substituents. Preferably the heterocyclic ring comprises from 4 to 7, preferably 5 to 6, ring atoms. A fused heterocyclic ring system may include carbocyclic rings and need only include one heterocyclic ring.

When used herein, the term "heterocyclyl" includes aromatic and non-aromatic single or fused rings comprising up to four hetero-atoms in the ring selected from oxygen, nitrogen and sulphur and optionally substituted with up to three substituents.

Suitably the heterocyclic ring comprises from 4 to 7, preferably 5 to 6, ring atoms. A fused heterocyclic ring system may include carbocyclic rings and need only include one heterocyclic ring. When substituted, a heteroaryl or a heterocyclyl group may have up to three substituents. Preferred such substituents include those previously mentioned for an aryl group as well as oxo.

When used herein, the terms "halogen" and "halo" include fluorine, chlorine, bromine and iodine and fluoro, chloro, bromo and iodo, respectively. It will be appreciated that compounds of formula (I) comprise one or more chiral centres so that the compounds exist as stereoisomers, including diastereoisomers and enantiomers. The present invention covers all such stereoisomers, and mixtures thereof, including racemates.

The compounds according to the invention are suitably provided in substantially pure form, for example at least 50% pure, suitable at least 60% pure, advantageously at least 75% pure, preferably at least 85% pure, more preferably at least 95% pure, especially at least 98% pure, all percentages being calculated as weight/weight. An impure or less pure form of a compound according to the invention may, for example, be used in the preparation of a more pure form of the same compound or of a related compound (for example a corresponding derivative) suitable for pharmaceutical use. Preferred compounds of formula (I) include:

2-[3-(6,8-Dibromo-2,3,4,5-tetrahydroquinolin-4-ylarnino)prop-l-ylamino]-lH-quinolin-

4-one;

2-[3-(6-Chloro-8-iodochroman-4-ylamino)prop-l-ylamino]-lH-quinolin-4-one; 2-[3-(8-Bromo-6-chloro-l,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]-lH- quinolin-4-one; 2-[3-(6-Bromo-8-chloro-l,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]-lH- quinolin-4-one;

2-[3-(6-Ethyl-8-iodo- 1 ,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]- lH-quinolin-

4-one; and

2-[3-(6,8-Dibromoclιroman-4-ylamino)prop-l-ylamino]-lH-quinolin-4-one.

Compounds of formula (I) may be readily prepared by reacting a compound of formula (II):

(π) in which R^, R3, m, Y and Z are as hereinbefore defined; with a cyclic ketone of formula (HI):

R!R CO

<ΠD

in which R^ and R⁴ are as hereinbefore defined, under reductive alkylation conditions.

Suitable reductive alkylating conditions are well known in the art and include for instance, the use of sodium triacetoxyborohydride in a solvent system such as DMF/acetic acid or sodium cyanoborohydride in methanol/acetic acid. Reductive alkylation with a ketone is typically carried out in refluxing methanol for a period of 16 - 40 h.

Compounds of formula (IT) may be prepared from a readily available 2- substituted quinolone, for instance a compound of the formula (IV):

(IN) in which R and m are as hereinbefore defined;

R8 is a leaving group such as halo, for instance chloro; and R9 is a CQ_6) alkyl, for instance methyl or ethyl, or an arylC(i_4) alkyl group; by displacement of R^ with a compound of the formula (V):

HNR YZH (V) in which R², Y and Z are as hereinbefore defined; or an activated derivative thereof; under nucleophilic displacement conditions; to form an intermediate which is then converted into a compound of formula (II) by acidic hydrolysis. Suitable conditions are well known in the art and include the use of a large excess of the compound of formula (V) to drive the reaction to completion and heating at a temperature of 60 - 130 °C. Addition of a base may be advantageous in some cases, eg a tertiary base such as NN-di(cyclohexyl)ethylamine. Acid hydrolysis may be carried out with refluxing concentrated hydrochloric acid where R^ is methyl or with trifluoroacetic acid at room temperature where R^ is 4-methoxybenzyl.

Compounds of formula (I) may also be prepared by reacting together a compound of formula (VI):

R¹R⁴CHΝR²YZH

(VI) in which R , R², Y and Z are as hereinbefore defined; with a compound of formula (IN); under nucleophilic displacement conditions followed by acid hydrolysis. When Z=O, the anion may be formed with a base eg sodium hydride for the nucleophilic displacement reaction. Compounds of formula (I) in which R² is other than hydrogen may be readily obtained from the corresponding compound of formula (I) in which R² is hydrogen by a conventional acylation or reductive alkylation reaction.

Pharmaceutically acceptable salts of compounds of formula (I) are formed with appropriate organic or inorganic acids by methods known in the art. For example, the base is reacted with a suitable inorganic or organic acid in an aqueous miscible solvent such as ethanol with isolation of the salt by removing the solvent or in an aqueous immiscible solvent when the acid is soluble therein, such as ethyl ether or chloroform, with the desired salt separating directly or isolated by removing the solvent.

The compounds of this invention are active against both Gram negative and Gram positive organisms, including Bacteroides, for instance B. fragilis BC 1 ,

Haemophilus, for instance H. influenzae Ql; Moraxella, for instance M. catarrhalis 1502; Streptococci, for instance S. pyogenes CΝ10 and S. pneumoniae PU7; Staphylococci, for instance S. aureus Oxford; Escherichia, for instance E. Coli DCO, Legionella, for instance L. pneumophila; Pseudomonas, for instance P. aeruginosa Dalgleish and Enterobacter, for instance Ent. faecelis I. In addition, compounds of this invention are active against Staphylococci organisms such as S. aureus and coagulase negative strains of Staphylocci such as S. epidermidis which are resistant (including multiply-resistant) to other anti-bacterial agents, for instance, β-lactam antibiotics such as, for example, methicillin; macrolides; aminoglycosides, and lincosamides. Compounds of the present invention are therefore useful in treating infections associated with MRS A, MRCNS and MRSΕ organisms. Compounds of the present invention are also active against strains of E. faecalis including vancomycin resistant strains and therefore of use in treating infections associated with VRΕ organisms. Furthermore, compounds of the present invention are useful in treating Staphylococci organisms which are resistant to mupirocin. Bacterial infections which may be treated include respiratory tract infections, otitis, meningitis, skin and soft tissue infections in man, mastitis in cattle, and respiratory infections in animals such as pigs and cattle.

Accordingly, in a further aspect, the present invention provides a method of treating bacterial infection in human or non-human animals, which method comprises administering a therapeutically effective amount of a compound of formula (I) as hereinbefore defined, to a human or non-human animal in need of such therapy. The present invention provides a pharmaceutical composition comprising a compound of formula (I) together with a pharmaceutically acceptable carrier or excipient.

The present invention also provides a method of treating bacterial infections in animals, especially in humans and in domesticated mammals, which comprises administering a compound of formula (I), or a composition according to the invention, to a patient in need thereof.

The invention further provides the use of a compound of formula (I) in the preparation of a medicament composition for use in the treatment of bacterial infections. The compounds and compositions according to the invention may be formulated for administration in any convenient way for use in human or veterinary medicine, by analogy with other antibiotics.

The compounds and compositions according to the invention may be formulated for administration by any route, for example oral, topical or parenteral. The compositions may, for example, be made up in the form of tablets, capsules, powders, granules, lozenges, creams, syrups, or liquid preparations, for example solutions or suspensions, which may be formulated for oral use or in sterile form for parenteral administration by injection or infusion. Tablets and capsules for oral administration may be in unit dosage form, and may contain conventional excipients including, for example, binding agents, for example, syrup, acacia, gelatin, sorbitol, tragacanth, or polyvinylpyrrollidone; fillers, for example lactose, sugar, maize-starch, calcium phosphate, sorbitol or glycine; tabletting lubricants, for example magnesium stearate, talc, polyethylene glycol or silica; disintegrants, for example potato starch; and pharmaceutically acceptable wetting agents, for example sodium lauryl sulphate. The tablets may be coated according to methods well known in normal pharmaceutical practice.

Oral liquid preparations may be in the form of, for example, aqueous or oily suspensions, solutions, emulsions, syrups or elixirs, or may be presented as a dry product for reconstitution with water or another suitable vehicle before use. Such liquid preparations may contain conventional additives, including, for example, suspending agents, for example sorbitol, methyl cellulose, glucose syrup, gelatin, hydroxyethyl cellulose, carboxymethyl cellulose, aluminium stearate gel or hydrogenated edible fats; emulsifying agents, for example lecithin, sorbitan monooleate or acacia; non-aqueous vehicles (which may include edible oils), for example almond oil, oily esters (for example glycerine), propylene glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-hydroxybenzoate or sorbic acid; and, if desired, conventional flavouring and colour agents. Compositions according to the invention intended for topical administration may, for example, be in the form of ointments, creams, lotions, eye ointments, eye drops, ear drops, impregnated dressings, and aerosols, and may contain appropriate conventional additives, including, for example, preservatives, solvents to assist drug penetration, and emollients in ointments and creams. Such topical formulations may also contain compatible conventional carriers, for example cream or ointment bases, and ethanol or oleyl alcohol for lotions. Such carriers may constitute from about 1% to about 98% by weight of the formulation; more usually they will constitute up to about 80% by weight of the formulation.

Compositions according to the invention may be formulated as suppositories, which may contain conventional suppository bases, for example cocoa-butter or other glycerides.

Compositions according to the invention intended for parenteral administration may conveniently be in fluid unit dosage forms, which may be prepared utilizing the compound and a sterile vehicle, water being preferred. The compound, depending on the vehicle and concentration used, may be either suspended or dissolved in the vehicle. In preparing solutions, the compound may be dissolved in water for injection and filter-sterilised before being filled into a suitable vial or ampoule, which is then sealed. Advantageously, conventional additives including, for example, local anaesthetics, preservatives, and buffering agents can be dissolved in the vehicle. In order to enhance the stability of the solution, the composition may be frozen after being filled into the vial, and the water removed under vacuum; the resulting dry lyophilized powder may then be sealed in the vial and a accompanying vial of water for injection may be supplied to reconstitute the liquid prior to use. Parenteral suspensions may be prepared in substantially the same manner except that the compound is suspended in the vehicle instead of being dissolved and sterilisation cannot be accomplished by filtration. The compound may instead be sterilised by exposure to ethylene oxide before being suspended in the sterile vehicle. Advantageously, a surfactant or wetting agent is included in such suspensions in order to facilitate uniform distribution of the compound.

A compound or composition according to the invention may suitably be administered to the patient in an antibacterially effective amount.

A composition according to the invention may suitably contain from 0.1 % by weight, preferably from 10 to 60% by weight, of a compound according to the invention (based on the total weight of the composition), depending on the method of administration.

The compounds according to the invention may suitably be administered to the patient at a daily dosage of from 1.0 to 50 mg/kg of body weight. For an adult human (of approximately 70 kg body weight), from 50 to 3000 mg, for example about 1500 mg, of a compound according to the invention may be administered daily. Suitably, the dosage for adult humans is from 5 to 20 mg/kg per day. Higher or lower dosages may, however, be used in accordance with normal clinical practice.

When the compositions according to the invention are presented in unit dosage form, each unit dose may suitably comprise from 25 to 1000 mg, preferable from 50 to 500 mg, of a compound according to the invention.

The following Intermediates and Examples illustrate the present invention.

Intermediates

Intermediate 1 - 2-(3-Aminoprop-l-ylamino)-Lfif-quinolin-4-one dihydrochloride a) 2-(3-Aminoprop-l-yIamino)-4-ethoxyquinoline To 2-chloro-4-ethoxyquinoline (J. Chem. Soc. Perkin Trans. 1, 1993, 181; 323 mg, 1.56 mmol) was added 1,3- diaminopropane (3.9 ml, 47 mmol). The mixture was stirred under argon at 60°C for 48 h. Excess diamine was removed in vacuo to leave a cream residue which was purified by flash chromatography on silica gel eluting with 6% (9: 1 MeOH/NH3) in DCM to give the title compound as a white solid (294 mg, 77%); δjj (CD3OD) 1.49 (3H, t), 1.79 (2H, m), 2.74 (2H, t), 3.51 (2H, t), 4.13 (2H, q), 6.09 (1H, s), 7.12 (1H, t), 7.45 (1H, t), 7.55 (1H, d), 7.90 (1H, d); MS (APCI-) 244 (100%, [M-H]"), 216 (34). b) 2-(3-Aminoprop-l-ylamino)-lfl^r-quinolin-4-one dihydrochloride To compound la (453 mg, 1.85 mmol) was added concentrated hydrochloric acid (20 ml). The mixture was refluxed under argon for 24 h. Excess hydrochloric acid was removed in vacuo to give the title compound as a pale yellow solid (547 mg, 100%); δjj (CD3OD) 2.00-2.15 (2H, m), 3.05-3.15 (2H, m), 3.55-3.65 (2H, m), 6.31 (1H, s), 7.39 (1H, t), 7.67 (1H, t), 7.75-7.90 (1H, m), 7.98 (1H, d); MS (APCI+) 218 (100%, MH+), 219 (38).

Examples

Example 1 - 2-[3-(6,8-DichIorochroman-4-ylamino)prop-l-ylamino]-lff-quinolin- 4-one - To a solution of 2-(3-aminoprop-l-ylamino)-lH-quinolin-4-one dihydrochloride (0.058 g, 0.2 mmol) in methanol (2 ml) and acetic acid (0.1 ml) was added sequentially sodium methoxide (0.5M in methanol, 0.8 ml, 0.4 mmol), 6,8-dichlorochroman-4-one (0.087 g, 0.4 mmol) and sodium cyanoborohydride (0.038 g, 0.6 mmol). The mixture was refluxed under argon for 31 h, adding further portions of sodium cyanoborohydride after 6 h, 22 h and 29 h. The mixture was then evaporated to dryness and purified by flash chromatography, eluting with 0-7% "10% ammonia in methanol" in dichloromethane to give an impure product. This material was further purified on a SCX cartridge, eluting with methanol followed by 0.2M NΗ3 in methanol to give the title compound as a white foam (0.046 g, 55%); δπ (CD3OD) 1.8-2.1 (4H, m), 2.65-2.9 (2H, m), 3.3-3.5 (2H, m), 3.81 (1H, t), 4.2-4.4 (2H, m), 5.64 (1H, s), 7.15-7.55 (5H, m), and 8.06 (1H, dd); MS (ES+) 418, 420 (95, 70%, MH+) and 201 (100).

Example 2 - 2-[3-(5,7-Dichloro-2,3-dihydrobenzofuran-3-ylamino)prop-l- y lamino] - LH-quinolin-4-one

(a) 5,7-Dichloro-2,3-dihydrobenzofuran-3-one. 2, 4-Dichlorophenoxy acetic acid (1.11 g, 5 mmol) and thionyl chloride (20 ml) were mixed together to give a suspension. On heating a solution formed, and this was refluxed for 1 h, then evaporated to dryness to give 2,4-dichlorophenoxyacetyl chloride (1.2 g); v_max (CH2CI2) 1804 cm'¹ (C=O). This acid chloride was dissolved in dichloromethane (20 ml), then aluminium chloride (0.73 g, 5.5 mmol) added. The mixture effervesced and quickly darkened. After 30 minutes the black mixture was poured onto ice, then filtered through kieselguhr, washing well with dichloromethane. The phases were separated, and the organic washed with brine, dried, and evaporated to give a dark residue (0.7 g). This was purified by flash chromatography, eluting with 30-90% dichloromethane in hexane, to give the impure title compound as an off-white solid (0.028 g, 2.8%); δfi (CDCI3) 4.78 (2H, s), 7.56 (1H, d), and 7.63 (1H, d). (b) 2-[3-(5,7-DichIoro-2,3-dihydrobenzofuran-3- ylamino)prop-l-ylamino]-lH-quinolin-4-one.

A solution of 2-(3-aminoprop-l-ylamino)-lH-quinolin-4-one dihydrochloride (0.038 g, 0.13 mmol) in methanol (2 ml) and acetic acid (0.1 ml) was treated with sodium methoxide (0.5M in methanol, 0.52 ml, 0.26 mmol). This solution was then added to compound 2a (0.028 g, 0.13 mmol), warmed, and then sodium cyanoborohydride (0.025 g, 0.4 mmol) added. The mixture was then refluxed for 16 h, and evaporated to dryness. The residue was repeatedly purified on three SCX cartridges, as in Example 1, to give the title compound as an off-white gum (0.0055 g, 10%); δπ (CD3OD) 1.8-1.95 (2Η, m), 2.6-2.85 (2H, m), 3.35-3.5 (2H,m), 4.5-4.8 (3H, m), 5.67 (1H, s) 7.2-7.6 (5H, m), and 8.10 (1H, d); MS (ES+) 404, 406 (100, 60%, MH+) and 201 (65).

Example 3 - 2-[3-(6,8-Dibromo-2,3,4,5-tetrahydroquinolin-4-ylamino)prop-l- ylamino]-lH-quinolin-4-one A solution of 2-(3-aminoprop-l-ylamino)-lH-quinolin-4-one dihydrochloride (0.038 g, 0.13 mmol) in methanol (2 ml) and acetic acid (0.1 ml) was treated with sodium methoxide (0.5M in methanol, 0.52 ml, 0.26 mmol). To this solution was then added 6,8-dibromo-2,3,4,5-tetrahydroquinolin-4-one (0.040 g, 0.13 mmol) in methanol (2 ml). The mixture was then warmed under argon and sodium cyanoborohydride (0.025 g, 0.4 mmol) added. The reaction was then refluxed for 40 h, adding more borohydride after 16 h and 24 h, and evaporated to dryness. The residue was purified on SCX cartridges followed by flash chromatography, eluting with 0-8% "10% ammonia in methanol" in dichloromethane, to give the title compound as an off-white gum (0.009 g, 14%); δfj (CD3OD) 1.65-2.0 (4Η, m), 2.65-2.8 (2H, m), 3.2-3.4 (4H, m), 3.65-3.75 (1H, m), 5.55 (1H, s), 7.1-7.55 (5H, m), and 7.97 (1H, d); MS (ES+) 505, 507, 509 (15, 30, 15%, MH+) and 218 (100); MS (ES-) 503, 505, 507 (50, 100, 45%, [M-H]").

Example 4 2-[3-(6-Chloro-8-iodochroman-4-ylamino)prop-l-ylamino]-lff- quinolin-4-one a) 6-ChIoro-8-iodo-chroman-4-one

6-Chlorochroman-4-one (0.182 g, 1 mmol) and iodine tris-trifluoroacetate (0.466 g, 1 mmol) were stirred in dichloromethane (10 ml) for 3 h at 20°C. Aqueous 20% sodium iodide solution (20 ml) was then added and the mixture stirred for 30 min. Dichloromethane (20 ml) was added and the organic layer washed with sat. sodium hydrogen carbonate solution and 5% sodium bisulfite solution. After drying (MgSO4) the organic layer was evaporated to dryness and the residue purified by chromatography on silica gel eluting with 0-60% dichloromethane in hexane to give 6-chloro-8-iodo- chroman-4-one as a white solid, (0.12 g, 39%). δπ (CDCL3) 2.84 (2H, dd), 4.64 (2H, dd), 7.85 (1H, d) and 7.91 (1H, d). b) 2-[3-(6-Chloro-8-iodochroman-4-ylamino)prop-l-yIamino]-lH-quinoIin-4-one

To a solution of 2-(3-aminoprop-l-ylamino)-lH-quinolin-4-one dihydrochloride (0.029 g, 0.1 mmol) in methanol (1 ml) and acetic acid (0.1 ml) was added sodium acetate (0.017 g, 0.207 mmol), compound 4a (0.046 g, 0.15 mmol) and then sodium cyanoborohydride (0.009 g, 0.15 mmol). The reaction was refluxed under argon for 18 h, and then evaporated to dryness. The residue was purified on a SCX cartridge, eluting with methanol followed by 0.2M NΗ3 in methanol to give the title compound as a white solid (0.030 g, 59%); δ_H (CD3OD) 1.84 (2H, m), 1.97 (2H, m), 2.76 (2H, m), 3.37 (2H, m), 3.79 (1H, m), 4.3 (2H, m), 5.62 (1H, s), 7.2 (1H, t), 7.28 (1H, d), 7.35 (1H, d) 7.51 (1H, m) 7.57 (1H, d), and 8.02 (1H, d); MS (ES+) 510, 512(100, 30%, MH+); MS (ES-) 508, 510 (100. 30%, [M-H]^").

Example 5 - 2-[3-(8-Bromo-6-chloro-l,2,3,4-tetrahydroquinolin-4- ylamino)propylamino]-lflf-quinolin-4-one.

(a) 3-(2-Bromo-4-chlorophenylamino)propionic acid - To a solution of 2-bromo-4- chloroaniline (2.06 g, 10 mmol) in acetonitrile (15 mL) at reflux was added 2-oxetanone (0.64 mL, 10 mmol) over a 20 minute period. After 3h the mixture was cooled and the acetonitrile was evaporated. The residue was recrystallised from toluene to yield the title compound as a white solid; MS (ES^") 278(35%)[M-H]^_.

(b) 8-Bromo-6-chloro-2,3-dihydro-lH-quinolin-4-one - To phosphorus pentoxide (15 g) was added 85 % orthophosphoric acid (6 mL) and the resultant mixture heated at 100°C for 0.5h. 3-(2-Bromo-4-chlorophenylamino)propionic acid (0.5 g, 1.8 mmol) was then added. After 2h the mixture was quenched with ice and stirred vigorously for 0.5h.

The mixture was filtered and the bright yellow precipitate washed with water and dried to yield the title compound; δ_H (CDCI3) 7.80(1H, d), 7.50(1H, d), 4.97(1H, br. s),

3.66(2H, t x d), 2.71(2H, t); MS (ES") 260(100%)[M-H]".

(c) 2-[3-(8-Bromo-6-chloro-l^,3,4-tetrahydroquinolin-4-ylamino)propylamino]- lff-quinolin-4-one - The title compound was prepared by an identical procedure to that described in Example 4b from 8-bromo-6-chloro-2,3-dihydro-lH-quinolin-4-one; δ_Η (CD3OD) 8.08(1H, d x d), 7.53(1H, t x d), 7.35(1H, d), 7.29(2H, m), 7.16QH, d),

5.68(1H, s), 3.78(1H, t), 3.48-3.39(4H, m) 2.83(2H, q), 2.07(1H, m) 1.92-1.75(3H, m);

MS (ES-) 461(54%)[M-H]".

Example 6 - 2-[3-(6-Bromo-8-chloro-l,2,3,4-tetrahydroquinoIin-4- ylamino)propylamino] - Iff -quinolin-4-one.

(a) 3-(4-Bromo-2-chlorophenylamino)propionic acid - The title compound was prepared by an identical procedure to that described for Example 5a from 4-bromo-2- chloroaniline; MS (ES^") 278(62%)[M-H]^".

(b) 6-Bromo-8-chloro-2,3-dihydro-Lfif^"-quinolin-4-one - The title compound was prepared by an identical procedure to that described in Example 5b from 3-(4-bromo-2- chlorophenylamino)propionic acid; δfj (CDCI3) 7.89(1H, d), 7.51(1H, d), 4.98(1H, br. s), 3.65(2H, t x d), 2.72(2H, t); MS (ES^') 260(100%)[M-H]". (c) 2-[3-(6-Bromo-8-chloro-l,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]- lff-quinolin-4-one - The title compound was prepared by an identical procedure to that described in Example 4b from 6-bromo-8-chloro-2,3-dihydro-lH-quinolin-4-one; δ_Η (CD3OD) 7.97(1H, d x d), 7.40(1H, t), 7.22(1H, d), 7.15-7.09(3H, m), 5.55(1H, s), 3.66(1H, t), 3.34-3.25(4H, m), 2.73-2.65(2H, m), 1.94-1.90(1H, m) 1.79-1.62(3H, m); MS (ES^") 461(100%)[M-H]".

Example 7 - 2-[3-(6-Bromo-8-ethyl-l,2,3,4-tetrahydroquinolin-4- ylamino)propylamino]-LH-quinoIin-4-one. (a) 3-(4-Bromo-2-ethylphenylamino)propionic acid - The title compound was prepared by an identical procedure to that described for Example 5a from 4-bromo-2- ethylaniline; MS (ES") 272(50%)[M-H]". (b) 6-Bromo-8-ethyl-2,3-dihydro-Lff-quinolin-4-one - The title compound was prepared by an identical procedure to that described in Example 5b from 3-(4-bromo-

2-ethylphenylamino)propionic acid; δ_H (CDCI3) 7.88(1H, d), 7.29(1H, d), 4.38(1H, br. s), 3.60(2H, t), 2.68(2H, t) 2.46(2H, q) 1.27(3H, t); MS (ES") 252(50%)[M-H]".

(c) 2-[3-(6-Bromo-8-ethyl-l,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]-Lff- quinolin-4-one - The title compound was prepared by an identical procedure to that described in Example 4b from 6-bromo-8-ethyl-2,3-dihydro-lH-quinolin-4-one; δjj

(CD3OD) 8.16(1Η, d x d), 7.36(1H, t), 7.24(1H, d), 7.21(1H, d), 7.06(1H, d), 6.98(1H, d), 5.65(1H, s), 3.58(1H, t), 3.33-3.19(4H, m), 2.76-2.72(2H, m), 2.28(2H, q), 1.81-

1.70(4H, m) 1.15(3H, t); MS (ES+) 455(100%)[MH]+.

Example 8 - 2-[3-(6-EthyI-8-iodo-l,2,3,4-tetrahydroquinolin-4- ylamino)propylamino]-LH-quinolin-4-one dihydrochloride.

(a) 3-(4-Ethylphenylamino)propionic acid - The title compound was prepared by an identical procedure to that described for Example 5a from 4-ethylaniline; MS (ES") 385(100%)[2M-H]", 192(76%)[M-H]".

(b) 6-Ethyl-2,3-dihydro-LH-quinoIin-4-one - The tide compound was prepared from 3-(4-ethylphenylamino)propionic acid, by an similar procedure to that described for Example 5b. The quenched reaction mixture was treated with aqueous ammonia solution (pH 9.0), extracted with the ethyl acetate, dried and evaporated to give the title compound; δ_H (CDCI3) 77.68(1H, d), 7.16(1H, d x d), 6.61(1H, d), 4.28(1H, br. s), 3.55(2H, t), 2.68(2H, t) 2.55(2H, q) 1.19(3H, t); MS (ES") 174(30%)[M-H]-.

(c) 6-Ethyl-8-iodo-2,3-dihydro-lH-quinolin-4-one - 6-Ethyl-2,3-dihydro-lH-quinolin- 4-one (0.66 g, 3.8 mmol) was dissolved in 2M hydrochloric acid (10 mL) and treated with iodine monochloride (0.6 g, 3.8 mmol) in 2M hydrochloric acid. After 10 minutes the mixture was diluted with dichloromethane (25 mL) and the layers separated. The organic phase was washed with 10% sodium bisulfite solution, dried and evaporated to yield the crude product. Chromatography over silica gel eluting with 40/60 petroleum ether/diethyl ether gave the title compound as a yellow solid; δπ (CDCI3) 7.69(2Η, m), 4.71(1H, br. s), 3.62(2H, t x d), 2.68(2H, t) 2.53(2H, q) 1.19(3H, t); MS (ES^") 300(35%)[M-H]".

(d) 2-[3-(6-Ethyl-8-iodo-l,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]-lff- quinoIin-4-one dihydrochloride - The title compound was prepared by an identical procedure to that described in Example 4b from 6-ethyl-8-iodo-2,3-dihydro-lH- quinolin-4-one. Conversion to the dihydrochloride was achieved by treatment with 1M methanolic hydrogen chloride, evaporation and trituration with diethyl ether to yield the title compound as a crystalline solid; δjj (CD₃OD) 8.12(1Η, d), 7.81-7.78(2H, m), 7.55-7.50(2H, m), 7.12(1H, d), 5.36(1H, s), 4.43(1H, t), 3.66(2H, t), 3.52-3.20(6H, m), 2.49(2H, q), 2.20-2.01(2H, m), 1.17(3H, t); MS (ES") 501(100%)[M-H]^".

Example 9 - 2-[3-(6-Methoxy-8-bromo-l,2,3,4-tetrahydroquinolin-4- ylamino)propylamino]-lff-quinolin-4-one.

(a) 3-(2-Bromo-4-methoxyphenylamino)propionic acid - To a solution of 3-(4- methoxyphenylamino)propionic acid (1.95g, 10 mmol) in acetic acid (20 mL) at 10°C was added dropwise a solution of bromine (1.61g, 10 mmol) in acetic acid (10 mL). After 2h stirring at room temperature the solvent was evaporated and the residue partitioned between ethyl acetate (50 mL) and water (50 mL). The organic layer was separated, dried and evaporated to yield the crude product. Chromatography over silica gel eluting with petroleum ether/ethyl acetate gave the title compound as a pale yellow solid; δ_H (CDCI3+ D₂O) 7.07(1H, d), 6.82(1H, d x d), 6.64(1H, d), 3.74(3H, s), 3.48(2H, d), 2.70(2H, s); MS (ES") 272(100%)[M-H]".

(b) 6-Methoxy-8-bromo-2,3-dihydro-lH-quinolin-4-one - The title compound was prepared by an identical procedure to that described in Example 5b from 3-(4- methoxy-2-bromophenylamino)propionic acid; δ_jj (CDCI3) 7.28(1H, d), 7.20(1H, d), 4.63(1H, br. s), 3.70(3H, s), 3.53(2H, t), 2.63(2H, t); MS (ES") 256(100%)[MH]+. (c) 2-[3-(6-Methoxy-8-bromo-l^,3,4-tetrahydroquinolin-4-ylamino)propylamino]- LH-quinoIin-4-one - The title compound was prepared by an identical procedure to that described in Example 4b from 6-methoxy-8-bromo-2,3-dihydro-lH-quinolin-4- one; δ_H (CD3OD) 7.97(1H, d), 7.40(1H, t), 7.19(1H, d), 7.14(1H, t), 6.86(1H, d), 6.73(1H, d), 5.55(1H, s), 3.75(1H, d), 3.56(3H, s), 3.30(2H, t), 3.25-3.20(2H, m), 2.76(2H, t), 1.98-1.95(1H, m), 1.82-1.74(3H, m); MS (ES") 459(10%)[MH+].

Example 10 - 2-[3-(8-Chloro-6-iodochroman-4-ylamino)prop-l-ylamino]-lff- quinolin-4-one a) 8-Chloro-6-iodo-chroman-4-one - 8-Chlorochroman-4-one (Ariamala and Balasubramanian, Tetrahedron, 45, 309-318 1989; 60 mg, 0.33 mmol) was iodinated using the method of Example 4a to give to give the title compound as a white solid, (59 mg, 58%); δ_H (CDCI3) 2.85 (2H, dd), 4.65 (2H, dd), 7.65 (1H, d) and 7.85 (1H, d). b) 2-[3-(8-Chloro-6-iodochroman-4-ylamino)prop-l-ylamino]-Lff-quinolin-4-one - The material of Example 10a (44 mg) was reductively coupled to 2-(3-aminoprop-l- ylamino)-lH-quinolin-4-one dihydrochloride (0.043 g, 0.15 mmol) using the method of Example 4b to give the title compound, (25 mg, 34%) as a white solid; δjj (CD3OD) 1.9, (2H, m), 2.1 (2H, m), 2.8 (2H, m), 3.4 (2H, m), 3.85 (IH, m), 4.35 (2H, m), 5.75 (IH, s), 7.25 (IH, t), 7.35 (IH, d), 7.5-7.7 (3H, m), and 8.05 (IH, d); MS (ES+) 510, 512(100, 30%, MH+); MS (ES-) 508, 510 (100, 30%, [M-H]").

Example 11 - 2-[3-(6,8-Dichloro-3-methylchroman-4-ylamino)prop-l-ylamino]- lH-quinoIin-4-one a) 6,8-Dichloro-3-methylchroman-4-one - To 6,8-dichloro-3-methylchromone (0.458 g, 2 mmol) in toluene (30 ml) and THF (14 ml) at -78°C under argon was added dropwise a 1M solution of DIB AL in toluene (5 ml). After 30 min at -78°C, methanol (20 ml) was added and the mixture allowed to warm to 20°C. Hydrochloric acid (0.25M , 20 ml) and toluene (50 ml) were added and the aqueous phase extracted with more toluene (50 ml). The combined organic phases were dried (MgSO4) and evaporated to dryness. The residue was purified by chromatography on silica gel eluting with 10- 100% dichloromethane in hexane to give the title compound as a white solid, (0.324 g, 70%), δ_H(CDCl₃) 1.25 (3H, d, J=6.9Hz), 2.9 (IH, m), 4.25 (IH, t, J=l 1.4Hz), 4.65 (IH, dd, J=5, 11.4Hz), 7.5 (IH, d, J=2.7Hz), 7.8 (IH, d, J= 2.7Hz). b) 2-[3-(6,8-Dichloro-3-methylchroman-4-ylamino)prop-l-yIamino]-l//-quinolin-4- one - To 2-(3-aminoprop-l-ylamino)-lH-quinolin-4-one dihydrochloride (0.058 g, 0.2 mmol), sodium acetate (33 mg, 0.4 mmol) in methanol (2 ml), acetic acid (0.1 ml) and sodium cyanoborohydride (0.02 g, 0.31 mmol) was refluxed under argon for 18 h. The mixture was then evaporated to dryness and purified first using a SCX cartridge, eluting with methanol followed by 0.2M NΗ3 in methanol then by flash chromatography, eluting with 2-8% "10% ammonia in methanol" in dichloromethane to give the faster eluted diastereoisomer of the title compound (6 mg, 7%); δ_ji (CD3OD) 1.0 (3H, d, J=7Hz), 1.9 (2H, m), 2.3 (IH, m), 2.9 (2H, m), 3.45 (2H, t, J=6.8Hz), 3.8 (IH, d,

J=4.2Hz), 4.2 (2H, d, J=5.4Hz ), 5.7 (IH, s) 7.2-7.4 (4H, m), 7.55 (IH, m) and 8.05 (IH, bd, J=8.1Hz); MS (ES+) 432, 430 (100, 70%, MH+), followed by the slower eluted diastereoisomer of the title compound (2.5 mg, 3%); δ_jj (CD3OD) 1.0 (3H, d, J=7Hz), 1.9 (2H, m), 2.2 (IH, m), 2.8 (2H, m), 3.4 (2H, m), 3.5 (IH, d, J=4Hz), 4.1 (IH, dd, J=4.2, 11Hz), 4.45, (IH, dd, J=2.7, 11Hz), 5.7 (IH, s) 7.2-7.6 (5H, m) and 8.1 (IH, bd, J=8Hz); MS (ES+) 432, 430 (100, 70%, MH+).

Example 12 - 2-[3-(6,8-Dibromochroman-4-ylamino)prop-l-ylamino]-lff-quinoIin- 4-one (a) 3-(2,4-Dibromophenoxy)propanoic acid - 2,4-Dibromophenol (7.56 g, 30 mmol) was dissolved in warm aqueous sodium hydroxide (2M, 15 ml, 30 mmol). To this was added slowly 2-oxetanone (1.89 ml, 30 mmol). The mixture was gently refluxed for lh, then cooled, acidified and extracted with diethyl ether. The organic phase was back extracted with saturated aqueous sodium hydrogen carbonate. This basic aqueous phase was acidified and extracted with diethyl ether. The combined organic extracts were washed with brine, dried and evaporated to give an off-white solid. This was recrystallised from dichloromethane / hexane to give the title compound as a white powder (3.48 g, 36%); δ_H (CDCI3) 2.92 (2H, t), 4.28 (2H, t), 6.8 (IH, d), 7.37 (IH, dd), and 7.66 (IH, d); MS (ES+) 321, 323, 325 (4, 8, 4%, MH+) and 249, 251, 253 (50, 100, 50).

(b) 6,8-Dibromochroman-4-one - 3-(2,4-Dibromophenoxy)propanoic acid (1.94 g, 6 mmol) was dissolved in benzene (75 ml), then phosphorus pentoxide (8.5 g, 60 mmol) added. The mixture was refluxed for 90 min, cooled and the benzene decanted off. The residue was carefully diluted with cold water, and extracted with diethyl ether. The combined organic phases were washed with dilute aqueous sodium hydrogen carbonate, water and brine, dried and evaporated to give the crude product. This was purified by flash chromatography, eluting with 0-20% diethyl ether in hexane, to afford the title compound as a yellow solid (1.33 g, 73%); δ_H (CDC1₃) 2.86 (2H, t), 4.65 (2H, t), 7.85 (IH, d), and 7.97 (IH, d); MS (ES-) 303, 305, 307 (30, 40, 20%, [M-H]^") and 249, 251, 253 (50, 100, 50).

(c) 2-[3-(6,8-Dibromochroman-4-ylamino)prop-l-ylamino]-lff-quinolin-4-one - To a solution of 2-(3-aminoprop-l-ylamino)-lH-quinolin-4-one dihydrochloride (0.044 g, 0.15 mmol) in methanol (1 ml) and acetic acid (0.1 ml) was added sequentially sodium methoxide (0.5M in methanol, 0.6 ml, 0.3 mmol), 6,8-dibromochroman-4-one (0.061 g, 0.2 mmol) and sodium cyanoborohydride (0.025 g, 0.4 mmol). The mixture was refluxed under argon for 19 h, adding a further portion of sodium cyanoborohydride after 3 h. The mixture was then cooled and purified on a SCX cartridge, washing with methanol followed by eluting with 0.2M NΗ3 in methanol. The product was further purified by flash chromatography, eluting with 0-6% "10% ammonia in methanol" in dichloromethane to give the title compound as a white foam (0.025 g, 33%); δjj (CD3OD) 1.8-2.1 (4H, m), 2.68-2.89 (2H, m), 3.39 (2H, t), 3.82 (IH, t), 4.21-4.44 (2H, m), 5.65 (IH, s), 7.17-7.35 (2H, m), 7.42-7.55 (3H, m), and 8.06 (IH, dd); MS (ES+) 506, 508, 510 (50, 100, 50%, MH+) and 218 (87).

Biological Data

1. Enzyme Inhibition

Compounds of the present invention may be assayed for their ability to inhibit the enzyme methionyl tRNA synthetase (MRS), using recombinant S. aureus MRS, as follows:

Reaction Mix (per 1ml )

Stock Volume (ul) Final Conct lOOmM Tris/Cl, pH 7.9 600 30 mM

250 mM KC1 75 mM

125 mM ATP 40 2.5 mM

250 mM MgCl2 80 10 mM

50 mM DTT 80 2 mM

0.5mM Met (S-35 hot and ι cold) 40 10 uM

Solid tRNA 4mg/ml 2mg/ml

(Mixed E. coli MRE 600)

H₂O 160

10 x Inhibitor (0 - 100 uM) 5 ul per well 0 - 10 uM

The reaction is started by adding 20 ul appropriately diluted pure enzyme (pre-incubated with inhibitor) to 25 ul reaction mix for 10 min at romm temperature. The reaction is terminated by the addition of 100 ul 5% trichloroacetic acid, 10% glycerol. The TCA precipitate is harvested onto dry Unifilter GFC plates using a Packard Filtermate Cell Harvester. The filters are washed with 4 x 200ul of 50% industrial methylated spirit, before drying. 30 ul of Microscint 20 is added to each well and plates are counted on a TopCount. (Packard 96 well counter).

Reagents

Mixed E. coli MRE 600 tRNA and ATP were purchased from Boehringer-Mannheim, L-[35 S] methionine from Amersham and other reagents from Sigma.

Pure recombinant S. aureus MRS (EP application number 97300317.1, SmithKline Beecham) was obtained using standard purification procedures. The enzyme is diluted in Dilution Buffer which consists of 10 mM Tris / CI, 2 mM DTT pH 7.9. Results

Examples 1 to 12 have IC50 values against S. aureus MRS in the range <3 to 100 nM. All are highly selective with respect to the mammalian enzyme (no inhibition of rat MRS up to 1 μM).

2. Antibacterial Activity

Compounds of the present invention were assayed for antibacterial activity against a range of pathogenic organisms (strains of S aureus, S pneumoniae, Efaecalis, H influenzae and M catarrhalis) in a standard MIC assay modified by the inclusion of cyclodextrin, to assist with solubility.

Examples 1, 3-8, 10 and 12 had MIC's <1 μg/ml against some strains of the organisms S. aureus, S. pneumoniae, and E.faecalis; and MIC's against M. Catarrhalis in the range 8-32 μg/ml.

Claims

1. A compound of formula (I):

(I) in which:

R! is aryl or heteroaryl;

R2 is hydrogen, C(i.g)alkyl, arylC(i_4)alkyl, arylC(2-4)alkenyl or C(i_6)alkylcarbonyl;

R3 is selected from halo, cyano, hydroxy, (Cj-6)alkyl (optionally substituted by halo, hydroxy, amino, carboxy or (Ci -6)alkoxycarbonyl), (C3"7)cycloalkyl, C(i_6)alkoxy, amino, mono- or di-(Cι-6)alkylarnino, acylamino, carboxy, (Cι-g)alkoxycarbonyl, carboxy(Cι-6)alkyloxy, (Cι-6)alkylthio, (Cι-6)alkylsulphinyl, (Cj-6)alkylsulphonyl, sulphamoyl, mono- and di-(Cι-6)alkylsulphamoyl, carbamoyl, mono- and di-(Ci-6)alkylcarbamoyl, and heterocyclyl; m is 0 or an integer from 1 to 3;

R⁴ and a substituent on Rl are linked to form a saturated bridge comprising one or two carbon atoms and a heteroatom selected from O and NR^;

R5 is hydrogen or C(i_6)alkyl;

Y is a linker group having from 2 to 6 methylene groups in a straight chain and in which one or more alkylene groups may have one or more CQ._QΛ alkyl substituents and which substituents may be linked to form a C2 or C3 alkylene bridge;

2. A compound of formula (I) which has the formula (LA):

(IA) in which R^, R3, m, Y, and Z are as defined in claim 1;

R⁴ and R⁶ form a bridge X(CH2)p where X is O or NR⁵ and p is 1 or 2 ;

R^ is selected from halo, cyano, hydroxy, (Cι-6)alkyl (optionally substituted by halo, hydroxy, amino, carboxy or (Cι-5)alkoxycarbonyl), (C3"7)cycloalkyl, C(i_6)alkoxy, amino, mono- or di-(Cι-5)alkylamino, acylamino, carboxy, (C|-6)alkoxycarbonyl, carboxy(Cι-6)alkyloxy, (Cι-6)alkylthio, (Cι-6)alkylsulphinyl, (Cι-6)alkylsulphonyl, sulphamoyl, mono- and di-(Ci-5)alkylsulphamoyl, carbamoyl, mono- and di-(Cι-6)alkylcarbamoyl, and heterocyclyl; and n is O, 1, 2 or 3.

3. A compound as claimed in claim 2 in which X is attached to the phenyl ring.

4. A compound as claimed in any one of claims 1 to 3 in which Y is (CH2)_n where n is 3.

5. A compound as claimed in any one of claims 1 to 4 in which Z is NH.

6. A compound as claimed in any one of claims 1 to 5 in which m is 0.

7. A compound as claimed in any one of claims 2 to 6 in which R^ is selected from halo, alkoxy, and alkyl.

8. A compound as claimed in any one of claims 2 to 7 in which n is 2.

9. A compound of formula (I) as claimed in claim 1 selected from:

2- [3 -(6 , 8-Dichlorochroman-4-y lamino)prop- 1 -ylamino] - 1 H-quinolin-4-one ;

2-[3-(5,7-DicWoro-2,3-dihydrobenzofuran-3-ylarm^o)prop-l-ylamino]-lH-quinolin-4- one;

2-[3-(6,8-Dibromo-2,3,4,5-tetrahyα oquinolin-4-ylamino)prop-l-ylamino]-lH-quinolin- 4-one;

2-[3-(6-Chloro-8-iodochroman-4-ylamino)prop- 1 -ylamino]- lH-quinolin-4-one;

2-[3-(8-Bromo-6-chloro- 1 ,2,3 ,4-tetrahydroquinolin-4-ylamino)propylamino]- 1H- quinolin-4-one;

2-[3-(6-Bromo-8-chloro- 1 ,2,3 ,4-tetrahydroquinolin-4-ylamino)propylamino]- 1H- quinolin-4-one;

2-[3-(6-Bromo-8-ethyl-l,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]-lH- quinolin-4-one; 2-[3-(6-Ethyl-8-iodo- 1 ,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]- lH-quinolin- 4-one dihydrochloride;

2-[3-(6-Methoxy-8-bromo- 1 ,2,3,4-tetrahydroquinolin-4-ylamino)propylamino]- 1H- quinolin-4-one; 2-[3-(8-Chloro-6-iodochroman-4-ylamino)prop-l-ylamino]-lH-quinolin-4-one;

2-[3-(6,8-Dichloro-3-methylchroman-4-ylamino)prop-l -ylamino]- lH-quinolin-4-one; and

2-[3-(6,8-Dibromochroman-4-ylamino)prop- 1 -ylamino]- lH-quinolin-4-one.

10. A pharmaceutical composition comprising an antibacterially effective amount of a substance or compound according to claim 1 together with a pharmaceutically acceptable carrier or excipient.

11. A compound as claimed in claim 1 for use in therapy.

12. A compound as claimed in claim 1 for use in the treatment of bacterial infections.

13. The use of a compound as claimed in claim 1 in the manufacture of a medicament for use in the treatment of bacterial infections.

14. A process for preparing a compound of formula (I) as claimed in claim 1 which process comprises:

(a) reacting a compound of formula (LI):

(Η) in which R^, R3, _m, Y and Z are as defined in claim 1 ; with a cyclic ketone of formula (HI):

R!R⁴CO

(IH)

in which R! and R⁴ are as defined in claim 1, under reductive alkylation conditions; or

(b) from a compound of the formula (IV):

(IN) in which R^ and m are as hereinbefore defined;

R8 is a leaving group such as halo, for instance chloro; and

R9 is a Cπ -6) alkyl, for instance methyl or ethyl, or an arylC(i_4) alkyl group; by displacement of R% with a compound of the formula (V):

HΝR²YZH

(V) in which R², Y and Z are as hereinbefore defined; or an activated derivative thereof; under nucleophilic displacement conditions; to form an intermediate which is then converted into a compound of formula (LI) by acidic hydrolysis.