WO2022214520A1 - Antibacterial compounds - Google Patents

Antibacterial compounds Download PDF

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Publication number
WO2022214520A1
WO2022214520A1 PCT/EP2022/059063 EP2022059063W WO2022214520A1 WO 2022214520 A1 WO2022214520 A1 WO 2022214520A1 EP 2022059063 W EP2022059063 W EP 2022059063W WO 2022214520 A1 WO2022214520 A1 WO 2022214520A1
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Prior art keywords
compound
ring
alkyl
inhibitor
compounds
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PCT/EP2022/059063
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French (fr)
Inventor
Jérôme Émile Georges GUILLEMONT
Magali Madeleine Simone Motte
José Manuel Bartolomé-Nebreda
Dirk Antonie LAMPRECHT
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Janssen Sciences Ireland Unlimited Company
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Publication of WO2022214520A1 publication Critical patent/WO2022214520A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
    • A61P31/04—Antibacterial agents
    • A61P31/06—Antibacterial agents for tuberculosis
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D487/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00
    • C07D487/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00 in which the condensed system contains two hetero rings
    • C07D487/04—Ortho-condensed systems

Definitions

  • the present invention relates to novel compounds.
  • the invention also relates to such compounds for use as a pharmaceutical and further for the use in the treatment of bacterial diseases, including diseases caused by pathogenic mycobacteria such as Mycobacterium tuberculosis.
  • Such compounds may work by targeting the respiratory chain, and thereby blocking all energy production of mycobacteria.
  • There are several ways of targeting the electron transport chain of mycobacteria for instance by interfering with ATP synthase in M. tuberculosis.
  • This particular invention focuses on the cytochrome bd target of the respiratory chain, which may be the primary mode of action.
  • such compounds are antitubercular agents, and in particular may act as such when combined with another tuberculosis drug (e.g. another inhibitor of a different target of the electron transport chain).
  • Mycobacterium tuberculosis is the causative agent of tuberculosis (TB), a serious and potentially fatal infection with a world-wide distribution.
  • TB tuberculosis
  • Estimates from the World Health Organization indicate that more than 8 million people contract TB each year, and 2 million people die from tuberculosis yearly. In the last decade, TB cases have grown 20% worldwide with the highest burden in the most impoverished communities. If these trends continue, TB incidence will increase by 41% in the next twenty years. Fifty years since the introduction of an effective chemotherapy, TB remains after AIDS, the leading infectious cause of adult mortality in the world. Complicating the TB epidemic is the rising tide of multi-drug-resistant strains, and the deadly symbiosis with HIV. People who are HIV-positive and infected with TB are 30 times more likely to develop active TB than people who are HIV-negative and TB is responsible for the death of one out of every three people with HIV/AIDS worldwide.
  • MDR-TB multi-drug-resistant strains
  • MDR-TB multi-drug-resistant strains
  • MDR-TB multi-drug-resistant strains
  • isoniazid and rifampin the most effective drugs of the four-drug standard, isoniazid and rifampin.
  • MDR-TB is lethal when untreated and cannot be adequately treated through the standard therapy, so treatment requires up to 2 years of "second-line" drugs. These drugs are often toxic, expensive and marginally effective.
  • infectious MDR-TB patients continue to spread the disease, producing new infections with MDR-TB strains.
  • drug resistant as used hereinbefore or hereinafter is a term well understood by the person skilled in microbiology.
  • a drug resistant Mycobacterium is a Mycobacterium which is no longer susceptible to at least one previously effective drug; which has developed the ability to withstand antibiotic attack by at least one previously effective drug.
  • a drug resistant strain may relay that ability to withstand to its progeny. Said resistance may be due to random genetic mutations in the bacterial cell that alters its sensitivity to a single drug or to different drugs.
  • MDR tuberculosis is a specific form of drug resistant tuberculosis due to a bacterium resistant to at least isoniazid and rifampicin (with or without resistance to other drugs), which are at present the two most powerful anti-TB drugs.
  • drug resistant includes multi drug resistant.
  • Another factor in the control of the TB epidemic is the problem of latent TB.
  • tuberculosis (TB) control programs about 2 billion people are infected by M. tuberculosis, though asymptomatically. About 10% of these individuals are at risk of developing active TB during their lifespan.
  • the global epidemic of TB is fuelled by infection of HIV patients with TB and rise of multi-drug resistant TB strains (MDR-TB).
  • MDR-TB multi-drug resistant TB strains
  • the reactivation of latent TB is a high risk factor for disease development and accounts for 32% deaths in HIV infected individuals.
  • To control TB epidemic the need is to discover new drugs that can kill dormant or latent bacilli.
  • the dormant TB can get reactivated to cause disease by several factors like suppression of host immunity by use of immunosuppressive agents like antibodies against tumor necrosis factor a or interferon-g.
  • immunosuppressive agents like antibodies against tumor necrosis factor a or interferon-g.
  • the only prophylactic treatment available for latent TB is two- three months regimens of rifampicin, pyrazinamide.
  • the tubercle bacilli enter healthy individuals by inhalation; they are phagocytosed by the alveolar macrophages of the lungs. This leads to potent immune response and formation of granulomas, which consist of macrophages infected with M. tuberculosis surrounded by T cells. After a period of 6-8 weeks the host immune response cause death of infected cells by necrosis and accumulation of caseous material with certain extracellular bacilli, surrounded by macrophages, epitheloid cells and layers of lymphoid tissue at the periphery.
  • Self-medication with antimicrobials is another major factor contributing to resistance.
  • Self-medicated antimicrobials may be unnecessary, are often inadequately dosed, or may not contain adequate amounts of active drug.
  • Patient compliance with recommended treatment is another major problem. Patients forget to take medication, interrupt their treatment when they begin to feel better, or may be unable to afford a full course, thereby creating an ideal environment for microbes to adapt rather than be killed.
  • M. tuberculosis is dependent on respiration to synthesise adequate amounts of ATP.
  • targeting the electron transport chain of the mycobacteria and thereby blocking energy production of mycobacteria is thought to be a potentially effective way of providing an efficient regimen against mycobacteria.
  • ATP synthase inhibitors as example of which is bedaquiline (marketed as Sirturo®)
  • cytochrome he inhibitors examples of which include the compound Q203 described in Journal article Nature Medicine, 19, 1157-1160 (2013) by Pethe et al “Discovery of Q203, a potent clinical candidate for the treatment of tuberculosis”, as well as patent applications such as internataional patent applcations WO 2017/001660, WO 2017/001661 , WO 2017/216281 and WO 2017/216283.
  • journal article Antimicrob. Agents Chemother, 2014, 6962-6965 by Arora et al describes compounds that target the respiratory bci complex in M. tuberculosis, and where deletion of the cytochrome bd oxidase generated a hypersusceptible mutant.
  • Journal article PANS (Early Edition), 2017, “Exploiting the synthetic lethality between terminal respiratory oxidases to kill Mycobacterium tuberculosis and clear host infection” by Kalia et al discloses various data around various tuberculosis compounds that target the respiratory chain.
  • Cytochrome bd itself is not essential for aerobic growth, but is upregulated and protects against a variety of stresses in various bacterial strains, for example as described in journal article Biochimica et Biophysica Acta 1837 (2014)
  • cytochrome bd inhibitors Various compounds are described in international patent applications WO 2012/069856 and WO 2017/103615, with the latter application describing such compounds as cytochrome bd inhibitors and indicates that thereapeutic combination products comprising one or more respiratory electron transport chain inhibitor and a cytochrome bd inhibitor is disclosed.
  • the compound CK-2-63 is described as a cytochrome bd inhibitor showing various inhibitor activity data, and combination data is also disclosed including combination of CK-2-63 with a mycobacterium cytochrome bcc inhibitor (e.g. AWE-402, where it is indicated therein that it is structurally related to the cytochrome bcc inhibitor Q203). It is indicated that such dual combination led to in increase in mycobacteria kill.
  • a mycobacterium cytochrome bcc inhibitor e.g. AWE-402
  • bedaquiline a known ATP synthase inhibitor
  • CK-2-63 showed an enhancement of bedaquiline activity at low concentrations.
  • AWE-402 a be inhibitor; see above
  • This particular invention focuses on novel compounds of the cytochrome bd target of the respiratory chain. New alternative/improved compounds are required, which may be tested/employed for use in combination.
  • R 1 represents Ci- 6 alkyl, -Br, hydrogen or -C(0)N(R ql )R q2 ;
  • R ql and R q2 independently represent hydrogen or Ci- 6 alkyl, or may be linked together to form a 3-6 membered carbocylic ring optionally substituted by one or more C 1-3 alkyl substituents;
  • Sub represents one or more optional substituents selected from halo (e.g, fluoro), -CN, C 1 - 6 alkyl and -O-Ci ⁇ alkyl (wherein the latter two alkyl moieties are optionally substituted by one or more fluoro atoms);
  • the “A” ring represents a 6-membered ring which may be aromatic or non-aromatic, or it represents a 5-membered aromatic ring containing one heteroatom (e.g. a sulfur heteroatom);
  • the “B” ring represents a 5-membered heteroaryl ring, which contains between one and four heteroatoms (e.g. selected from nitrogen, oxygen and sulfur), and which “B” ring is optionally substituted by one or more substituents selected from halo and C 1 - 6 alkyl (itself optionally substituted by one or more fluoro atoms);
  • L 1 represents an optional linker group, and hence may be a direct bond or -C(R xl )(R x2 );
  • R xl and R x2 independently represent hydrogen or C 1 -3 alkyl;
  • ring C represents a 5-membered aromatic ring containing at least one heteroatom (preferably containing at least one nitrogen atom), and which ring is optionally substituted by one or more substituents independently selected from R f ;
  • ring D represents a 6-membered aromatic ring containing at least one heteroatom (preferably containing at least one nitrogen atom), and which ring is optionally substituted by one or more substituents independently selected from R g ;
  • Y b represents -[(CH 2 )i-4] ⁇ (so forming a 3- to 6-membered N-containing ring), and R h represents one or more optional substituents on such ring;
  • R a , R b , R c , R d and R e independently represent hydrogen or a substituent selected from B 1 ; each R f , each R s and each R h (which are optional substituents), when present, independently represent a substituent selected from B 1 ; each B 1 independently represents a substituent selected from:
  • R dl represents Cue alkyl, preferably C 1-3 alkyl, optionally substituted by one or more halo (e.g. fluoro) atoms;
  • R el , R e2 , R e3 , R e4 and R e5 each independently represent hydrogen or Cue alkyl optionally substituted by one or more fluoro atoms; or a pharmaceutically-acceptable salt thereof, which compounds may be referred to herein as “compounds of the invention”.
  • compounds of the invention include those described here (e.g. above), in which: each B 1 independently represents a substituent selected from:
  • salts include acid addition salts and base addition salts.
  • Such salts may be formed by conventional means, for example by reaction of a free acid or a free base form of a compound of formula 1 with one or more equivalents of an appropriate acid or base, optionally in a solvent, or in a medium in which the salt is insoluble, followed by removal of said solvent, or said medium, using standard techniques (e.g. in vacuo, by freeze-drying or by filtration). Salts may also be prepared by exchanging a counter-ion of a compound of the invention in the form of a salt with another counter-ion, for example using a suitable ion exchange resin.
  • the pharmaceutically acceptable acid addition salts as mentioned hereinabove are meant to comprise the therapeutically active non-toxic acid addition salt forms that the compounds of formula (I) are able to form.
  • These pharmaceutically acceptable acid addition salts can conveniently be obtained by treating the base form with such appropriate acid.
  • Appropriate acids comprise, for example, inorganic acids such as hydrohalic acids, e.g. hydrochloric or hydrobromic acid, sulfuric, nitric, phosphoric and the like acids; or organic acids such as, for example, acetic, propanoic, hydroxyacetic, lactic, pyruvic, oxalic (i.e. ethanedioic), malonic, succinic (i.e.
  • prodrug of a relevant compound of the invention includes any compound that, following oral or parenteral administration, is metabolised in vivo to form that compound in an experimentally-detectable amount, and within a predetermined time (e.g. within a dosing interval of between 6 and 24 hours (i.e. once to four times daily)).
  • parenteral administration includes all forms of administration other than oral administration.
  • Prodrugs of compounds of the invention may be prepared by modifying functional groups present on the compound in such a way that the modifications are cleaved, in vivo when such prodrug is administered to a mammalian subject. The modifications typically are achieved by synthesising the parent compound with a prodrug substituent.
  • Prodrugs include compounds of the invention wherein a hydroxyl, amino, sulfhydryl, carboxy or carbonyl group in a compound of the invention is bonded to any group that may be cleaved in vivo to regenerate the free hydroxyl, amino, sulfhydryl, carboxy or carbonyl group, respectively.
  • prodrugs include, but are not limited to, esters and carbamates of hydroxy functional groups, esters groups of carboxyl functional groups, N-acyl derivatives and N-Mannich bases. General information on prodrugs may be found e.g. in Bundegaard, H. “Design of Prodrugs” p. 1-92, Elesevier, New York-Oxford (1985).
  • Compounds of the invention may contain double bonds and may thus exist as E ( Chrysler ) and Z ( 1966 ) geometric isomers about each individual double bond.
  • Positional isomers may also be embraced by the compounds of the invention. All such isomers (e.g. if a compound of the invention incorporates a double bond or a fused ring, the cis- and trans- forms, are embraced) and mixtures thereof are included within the scope of the invention (e.g. single positional isomers and mixtures of positional isomers may be included within the scope of the invention).
  • tautomer or tautomeric form
  • proton tautomers also known as prototropic tautomers
  • Valence tautomers include interconversions by reorganisation of some of the bonding electrons.
  • Compounds of the invention may also contain one or more asymmetric carbon atoms and may therefore exhibit optical and/or diastereoisomerism.
  • Diastereoisomers may be separated using conventional techniques, e.g. chromatography or fractional crystallisation.
  • the various stereoisomers may be isolated by separation of a racemic or other mixture of the compounds using conventional, e.g. fractional crystallisation or HPLC, techniques.
  • the desired optical isomers may be made by reaction of the appropriate optically active starting materials under conditions which will not cause racemisation or epimerisation (i.e. a ‘chiral pool’ method), by reaction of the appropriate starting material with a ‘chiral auxiliary’ which can subsequently be removed at a suitable stage, by derivatisation (i.e.
  • a resolution for example with a homochiral acid followed by separation of the diastereomeric derivatives by conventional means such as chromatography, or by reaction with an appropriate chiral reagent or chiral catalyst all under conditions known to the skilled person.
  • stereoisomers including but not limited to diastereoisomers, enantiomers and atropisomers
  • mixtures thereof e.g. racemic mixtures
  • stereochemistry of any particular chiral atom is not specified, then all stereoisomers are contemplated and included as the compounds of the invention. Where stereochemistry is specified by a solid wedge or dashed line representing a particular configuration, then that stereoisomer is so specified and defined.
  • the compounds of the present invention may exist in unsolvated as well as solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like, and it is intended that the invention embrace both solvated and unsolvated forms.
  • the present invention also embraces isotopically-labeled compounds of the present invention which are identical to those recited herein, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature (or the most abundant one found in nature). All isotopes of any particular atom or element as specified herein are contemplated within the scope of the compounds of the invention. Exemplary isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, fluorine, chlorine and iodine, such as 2H, 3 H, "C 13 C, 14 C , 13 N, ' ⁇ .
  • isotopically-labeled compounds of the present invention are useful in compound and for substrate tissue distribution assays.
  • Tritiated ( 3 H) and carbon-14 ( l4 C) isotopes are useful for their ease of preparation and detectability.
  • substitution with heavier isotopes such as deuterium (i.e., 2H may afford certain therapeutic advantages resulting from greater metabolic stability (e.g., increased in vivo half-life or reduced dosage requirements) and hence may be preferred in some circumstances.
  • Positron emitting isotopes such as l5 0, l3 N, n C and 18 F are usefuI for positron emission tomography (PET) studies to examine substrate receptor occupancy.
  • Isotopically labeled compounds of the present invention can generally be prepared by following procedures analogous to those disclosed in the description/Examples hereinbelow, by substituting an isotopically labeled reagent for a non-isotopieally labeled reagent.
  • Cu 4 alkyl groups (where q is the upper limit of the range) defined herein may be straight-chain or, when there is a sufficient number (i.e. a minimum of two or three, as appropriate) of carbon atoms, be branched-chain, and/or cyclic (so forming a Cs- q -cycloalkyl group).
  • Such cycloalkyl groups may be monocyclic or bicyclic and may further be bridged. Further, when there is a sufficient number (i.e. a minimum of four) of carbon atoms, such groups may also be part cyclic.
  • Such alkyl groups may also be saturated or, when there is a sufficient number (i.e. a minimum of two) of carbon atoms, be unsaturated (forming, for example, a C 2 - q alkenyl or a C 2 - q alkynyl group).
  • C3- q cycloalkyl groups may be monocyclic or bicyclic alkyl groups, which cycloalkyl groups may further be bridged (so forming, for example, fused ring systems such as three fused cycloalkyl groups).
  • Such cycloalkyl groups may be saturated or unsaturated containing one or more double bonds (forming for example a cycloalkenyl group).
  • Substituents may be attached at any point on the cycloalkyl group. Further, where there is a sufficient number (i.e. a minimum of four) such cycloalkyl groups may also be part cyclic.
  • halo when used herein, preferably includes fluoro, chloro, bromo and iodo.
  • Heterocyclic groups when referred to herein may include aromatic or non-aromatic heterocyclic groups, and hence encompass heterocycloalkyl and hetereoaryl.
  • aromatic or non-aromatic 5- or 6-membered rings may be heterocyclic groups (as well as carbocyclic groups) that have 5- or 6-members in the ring.
  • Heterocycloalkyl groups that may be mentioned include non-aromatic monocyclic and bicyclic heterocycloalkyl groups in which at least one (e.g. one to four) of the atoms in the ring system is other than carbon (i.e. a heteroatom), and in which the total number of atoms in the ring system is between 3 and 20 (e.g. between three and ten, e.g between 3 and 8, such as 5- to 8-). Such heterocycloalkyl groups may also be bridged. Further, such heterocycloalkyl groups may be saturated or unsaturated containing one or more double and/or triple bonds, forming for example a C?- q heterocycloalkenyl (where q is the upper limit of the range) group.
  • C2- q heterocycloalkyl groups that may be mentioned include 7-azabicyclo[2,2.1]heptanyl, 6-azabicyclo[3.1.1]heptanyl, 6- azabicyclo[3.2.1]-octanyl, 8-azabicyclo-[3.2.
  • heterocycloalkyl groups may, where appropriate, be located on any atom in the ring system including a heteroatom.
  • the point of attachment of heterocycloalkyl groups may be via any atom in the ring system including (where appropriate) a heteroatom (such as a nitrogen atom), or an atom on any fused carbocyclic ring that may be present as part of the ring system.
  • Heterocycloalkyl groups may also be in the N- or S- oxidised form.
  • Heterocycloalkyl mentioned herein may be stated to be specifically monocyclic or bicyclic.
  • Aromatic groups may be aryl or heteroaryl.
  • Aryl groups that may be mentioned include Ce-20, such as Ce-i2 (e.g. Ce-io) aryl groups. Such groups may be monocyclic, bicyclic or tricyclic and have between 6 and 12 (e.g. 6 and 10) ring carbon atoms, in which at least one ring is aromatic.
  • Ceuo aryl groups include phenyl, naphthyl and the like, such as 1,2,3,4-tetrahydronaphthyl.
  • the point of attachment of aryl groups may be via any atom of the ring system. For example, when the aryl group is polycyclic the point of attachment may be via atom including an atom of a non-aromatic ring. However, when aryl groups are polycyclic (e.g. bicyclic or tricyclic), they are preferably linked to the rest of the molecule via an aromatic ring. Most preferred aryl groups that may be mentioned herein are “phen
  • heteroaryl when used herein refers to an aromatic group containing one or more heteroatom(s) (e.g. one to four heteroatoms) preferably selected from N, O and S.
  • Heteroaryl groups include those which have between 5 and 20 members (e.g. between 5 and 10) and may be monocyclic, bicyclic or tricyclic, provided that at least one of the rings is aromatic (so forming, for example, a mono-, bi-, or tricyclic heteroaromatic group).
  • the heteroaryl group is polycyclic the point of attachment may be via any atom including an atom of a non-aromatic ring.
  • heteroaryl groups are polycyclic (e.g.
  • bicyclic or tricyclic they are preferably linked to the rest of the molecule via an aromatic ring.
  • Heteroaryl groups that may be mentioned include 3,4-dihydro- l//-isoquinolinyl, 1 ,3-dihydroisoindolyl,
  • heteroaryl groups may, where appropriate, be located on any atom in the ring system including a heteroatom.
  • the point of attachment of heteroaryl groups may be via any atom in the ring system including (where appropriate) a heteroatom (such as a nitrogen atom), or an atom on any fused carboeyclic ring that may be present as part of the ring system.
  • the heteroaryl group is monocyclic or bicyclic.
  • the heteroaryl may consist of a five-, six- or seven-membered monocyclic ring (e.g. a monocyclic heteroaryl ring) fused with another five-, six- or seven-membered ring (e.g. a monocyclic aryl or heteroaryl ring).
  • Heteroatoms that may be mentioned include phosphorus, silicon, boron and, preferably, oxygen, nitrogen and sulfur.
  • aromatic groups When “aromatic” groups are referred to herein, they may be aryl or heteroaryl.
  • aromatic linker groups When “aromatic linker groups” are referred to herein, they may be aryl or heteroaryl, as defined herein, are preferably monocyclic (but may be polycyclic) and attached to the remainder of the molecule via any possible atoms of that linker group. However, when, specifically carbocyclic aromatic linker groups are referred to, then such aromatic groups may not contain a heteroatom, i.e. they may be aryl (but not heteroaryl).
  • a group may be substituted by one or more substituents (e.g, selected from C 1 - 6 alkyl), then those substituents (e.g. alkyl groups) are independent of one another. That is, such groups may be substituted with the same substituent (e.g. same alkyl substituent) or different (e.g. alkyl) substituents.
  • substituents e.g. selected from C 1 - 6 alkyl
  • R 1 represents hydrogen or C 1-3 alkyl.
  • Preferred compounds of the invention include those in which R 1 represents C 1-3 alkyl such as methyl or ethyl.
  • R 1 represents methyl.
  • Sub is not present.
  • Sub represents one or two substituents selected from halo (e.g. fluoro) atom, -CN and C 1-2 alkyl (e.g. methyl).
  • compounds of the invention may have an aromatic A ring such as in formula lb:
  • Compounds of the invention may have an aromatic 5-membered ring in which X x represents a heteroatom such as nitrogen, oxygen or sulfur, such as in formula Ic.
  • X x represents a heteroatom such as nitrogen, oxygen or sulfur, such as in formula Ic.
  • the “A” ring is unsubstituted or substituted with one fluoro atom.
  • the “A” ring is a 6-membered aromatic or non-aromatic ring.
  • Preferred compounds of the invention include those in which the “B” ring contain at least one nitrogen atom (in an embodiment, at the ring junction); and/or contains one, two, three or four heteroatoms in total.
  • compounds of the invention are those in which the “B” ring and adjacent 6 membered non-aromatic ring are represented by a sub-formula
  • any one or two of X 3 , X 4 and X 5 represents a heteroatom (e.g. N, O and/or S; and, in an embodiment, N) and the other(s) represents C (or CH).
  • preferred compounds of the invention include those in which: one of X 1 and X 2 represents N; and none, one or two of X 3 , X 4 and X 5 represents N.
  • the “B” ring and adjacent 6 membered non-aromatic ring in compounds of the invention may be depicted as follows in sub formula (II) (in which the left hand side would be further bound to the requisite quinolinone, or tetrahydro- quinolinone, of formula (I) and the right hand side would be further bound to the L 1 group of formula (I)):
  • one of X 1 and X 2 represents N (i.e. there is an essential nitrogen at the ring junction) and the other represents C; the other integers X 3 , X 4 and X 5 may represent C (or CH) or a heteroatom (such as N, O and/or S); and/or none, any one or two of X 3 , X 4 and X "1 represents a heteroatom (e.g, N, O and/or S) and the other represents C (or CH), and in which in all of the cases above, it will be understood that the rules of valency will need to be adhered to.
  • the “B” ring and adjacent 6 membered non-aromatic ring in compounds of the invention may be depicted as follows in sub formula (II) (in which the left hand side would be further bound to the requisite quinolinone, or tetrahydro- quinolinone, of formula (I) and the right hand side would be further bound to the L 1 group of formula (I)):
  • one of X 1 and X 2 represents N (i.e. there is an essential nitrogen at the ring junction) and the other represents C; the other integers X 3 , X 4 and X 3 may represent C (or CH) or a heteroatom (such as N,
  • any one or two of X 3 , X 4 and X 3 represents a heteroatom (e.g. N, O and/or S) and the other represents C (or CH), and in which in all of the cases above, it will be understood that the rules of valency will need to be adhered to.
  • preferred compounds of the invention include those in which in the sub-formula (II) depicted above:
  • X 1 , X 3 and X 5 represent a heteroatom (e.g. nitrogen) and X 2 and X 4 represent C (or CH).
  • preferred compounds of the invention include those in which in the sub-formula (II) depicted above:
  • X 2 , X 3 and X 3 represent a heteroatom (e.g. nitrogen) and X 1 and X 4 represent C (or CH).
  • the sub-formula (II) represents: In an embodiment, the sub-formula (II) represents: In a preferred embodiment the “B” ring and adjacent 6 membered non-aromatic ring in compounds of the invention may be depicted as follows, (in which the left hand side would be further bound to the requisite quinolinone, or tetrahydro-quinolinone, of formula (I) and the right hand side would be further bound to the L 1 group of formula
  • preferred compounds of the invention include those in which in the sub-formula (II) depicted above:
  • X 2 and X 3 represent a heteroatom (e.g. nitrogen) and X 1 , X 4 and X 5 represent C (or CH).
  • L 1 represents a direct bond or -C(R xl )(R x2 )-;
  • R xl and R x2 independently represent hydrogen for example: L 1 may specifically represent a direct bond or -CHb- (or, in a more specific embodiment, a direct bond).
  • L 1 represents a direct bond. In an alternative embodiment, L 1 represents -Ctb- (but is preferably a direct bond).
  • Z 1 represents (i), (ii) or (iii) (e.g. Z 1 represents (i) or (ii)).
  • Z 1 represents an aromatic ring (i.e. (i), (ii) or (iii) above), for instance (i) or (ii).
  • compounds of the invention include those in which when ring C is present, it represents a 5-membered aromatic ring, it contains one, two or three heteroatoms preferably selected from nitrogen, oxygen and sulfur; in a further embodiment, such ring is optionally substituted by one or two substituents independently selected from R f ; when ring D is present, it represents a 6-membered aromatic ring containing one nitrogen atom; and, in a further embodiment, such ring is optionally substituted by one or two substituents independently selected from R g ;
  • R a , R b , R c , R d and R e independently represent hydrogen or a substituent selected from B 1 ;
  • R f and R g each independently represent a substituent selected from B 1 .
  • such aromatic 5-membered (optionally substituted) ring may: (i) contain one sulfur atom (so forming a thienyl); (ii) contain one nitrogen and one sulfur atom (so forming e.g. thiazolyl); (iii) contain two nitrogen atoms (so forming e.g. a pyrazolyl); (iv) contains two nitrogen atoms and one sulfur atom; (v) contains two nitrogen atoms and one oxygen atom; (vi) contains three nitrogen atoms.
  • Ring D when Ring D is present (i.e. Z 1 represents (iii)), then such aromatic 6-membered ring may contain one nitrogen atom, so forming a pyridyl group (e.g. a 3- pyridyl group, or, in an alternative embodiment, a 2-pyridyl group or a 4-pyridyl group).
  • a pyridyl group e.g. a 3- pyridyl group, or, in an alternative embodiment, a 2-pyridyl group or a 4-pyridyl group.
  • further preferred compounds of the inventions include those in which: none, but preferably, one or two (e.g. one) of R a , R b , R c , R d and R e represents B 1 and the others represent hydrogen; and/or one or two (e.g. one) of R b .
  • R c and R d (preferably R c ) represents B 1 and the others represent hydrogen.
  • preferred compounds of the inventions include those in which: R b and one of R c or R d represent B 1 and the others represent hydrogen.
  • preferred compounds of the inventions include those in which: R b and R c represent B 1 and the others represent hydrogen.
  • preferred compounds of the inventions include those in which: R b and R d represent B 1 and the others represent hydrogen.
  • preferred compounds of the inventions include those in which: R b represent B' and the others represent hydrogen.
  • preferred compounds of the inventions include those in which: R c represent B 1 and the others represent hydrogen.
  • R c represent B 1 and the others represent hydrogen.
  • R e2 and R e 4 independently represent hydrogen
  • R el , R e3 and R e5 each independently represent C 1-3 alkyl (e.g. methyl) substituted by one or more fluoro atoms.
  • yet further preferred compounds of the inventions include those in which:
  • B 1 represents a substituent selected from:
  • halo e.g. fluoro or chloro
  • fluoro e.g. fluoro or chloro
  • C 1 - 6 alkyl preferably C 1-3 alkyl, substituted by one or more fluoro atom
  • B 1 represents a substituent selected from halo (e.g. fluoro or chloro), C 1-3 alkyl (optionally substituted by one or more fluoro atom) and -OR el (in which R el represents C 1-3 alkyl optionally substituted by one or more fluoro atom, so forming e.g. -OCH 3 or-OCF 3 ).
  • B 1 is selected from fluoro, -CH 3 , -OCH3, -CF 3 , -CHF 2 , -CH 2 CF 3 , -CH2CHF2, -CH 2 CH 2 CF 3 and -OCF 3 .
  • B 1 may represent isopropyl or -S(0) 2 CF 3 .
  • B 1 is selected from fluoro, -CH 3 , -CF 3 , -OCH 3 and
  • Z 1 represents:
  • ring C represents a 5-membered aromatic ring containing at least two heteroatom, wherein at least one of said hetero atom is a nitrogen atom, and which ring is substituted by one or more substituents independently selected from R f ; one or two (e.g. one) of R b R c and R d (preferably R c ) represents B 1 and the others represent hydrogen;
  • R f and R h independently represent hydrogen or a substituent selected from B 1 ; each B 1 independently represents a substituent selected from:
  • R dl represents C 1 - 6 alkyl, preferably C 1-3 alkyl, optionally substituted by one or more fluoro atoms;
  • R el represent hydrogen or C 1-6 alkyl optionally substituted by one or more fluoro atoms.
  • the compounds according to the invention have surprisingly been shown to be suitable for the treatment of a bacterial infection including a mycobacterial infection, particularly those diseases caused by pathogenic mycobacteria such as Mycobacterium tuberculosis (including the latent and drug resistant form thereof).
  • the present invention thus also relates to compounds of the invention as defined hereinabove, for use as a medicine, in particular for use as a medicine for the treatment of a bacterial infection including a mycobacterial infection.
  • Such compounds of the invention may act by interfering with ATP synthase in M. tuberculosis, with the inhibition of cytochrome bd activity being the primary mode of action.
  • Such bd inhibition may have an effect in killing mycobacteria (and hence having an anti-tuberculosis effect directly).
  • cytochrome bd is not necessarily essential for aerobic growth, it may have the most pronounced effect in combination with another inhibitor of a target of the electron transport chain of mycobacteria.
  • Such compounds may be tested for cytochrome bd activity by testing in an enzymatic assay, and may also be tested for activity in the treatment of a bacterial infection (e.g. mycobacterial infection) by testing the kill kinetics, for example of such compounds alone or in combination (as mentioned herein, e.g.
  • Cytochrome bd is a component of the electron transport chain, and therefore may he implicated with ATP synthesis, for instance alone or especially with one or more other inhibitor(s) of a target of the electron transport chain of mycobacteria.
  • the present invention also relates to the use of a compound of the invention, as well as any of the pharmaceutical compositions thereof as described hereinafter for the manufacture of a medicament for the treatment of a bacterial infection including a mycobacterial infection (for instance when such compound of the invention is used in combination with another inhibitor of a target of the electron transport chain of mycobacteria).
  • the invention provides a method of treating a patient suffering from, or at risk of, a bacterial infection, including a mycobacterial infection, which comprises administering to the patient a therapeutically effective amount of a compound or pharmaceutical composition according to the invention (for instance a therapeutically effective amount of a compound or pharmaceutical composition of the invention, in combination with one or more other inhibitor(s) of a target of the electron transport chain of mycobacteria).
  • the compounds of the present invention also show activity against resistant bacterial strains (for instance alone or in combination with another inhibitor of a target of the electron transport chain of mycobacteria).
  • resistant bacterial strains for instance alone or in combination with another inhibitor of a target of the electron transport chain of mycobacteria.
  • the invention also relates to a composition
  • a composition comprising a pharmaceutically acceptable carrier and, as active ingredient, a therapeutically effective amount of a compound according to the invention.
  • the compounds according to the invention may be formulated into various pharmaceutical forms for administration purposes. As appropriate compositions there may be cited all compositions usually employed for systemically administering drugs.
  • an effective amount of the particular compound, optionally in addition salt form, as the active ingredient is combined in intimate admixture with a pharmaceutically acceptable carrier, which carrier may take a wide variety of forms depending on the form of preparation desired for administration.
  • a pharmaceutically acceptable carrier which carrier may take a wide variety of forms depending on the form of preparation desired for administration.
  • These pharmaceutical compositions are desirable in unitary dosage form suitable, in particular, for administration orally or by parenteral injection.
  • any of the usual pharmaceutical media may be employed such as, for example, water, glycols, oils, alcohols and the like in the case of oral liquid preparations such as suspensions, syrups, elixirs, emulsions and solutions; or solid carriers such as starches, sugars, kaolin, diluents, lubricants, binders, disintegrating agents and the like in the case of powders, pills, capsules and tablets. Because of their ease in administration, tablets and capsules represent the most advantageous oral dosage unit forms in which case solid pharmaceutical carriers are obviously employed.
  • the carrier will usually comprise sterile water, at least in large part, though other ingredients, for example, to aid solubility, may be included.
  • injectable solutions for example, may be prepared in which the carrier comprises saline solution, glucose solution or a mixture of saline and glucose solution.
  • injectable suspensions may also be prepared in which case appropriate liquid carriers, suspending agents and the like may be employed.
  • solid form preparations which are intended to be converted, shortly before use, to liquid form preparations.
  • the pharmaceutical composition will preferably comprise from 0.05 to 99 % by weight, more preferably from 0.1 to 70 % by weight, even more preferably from 0.1 to 50 % by weight of the active ingredient(s), and, from 1 to 99.95 % by weight, more preferably from 30 to 99.9 % by weight, even more preferably from 50 to 99.9 % by weight of a pharmaceutically acceptable carrier, all percentages being based on the total weight of the composition.
  • the pharmaceutical composition may additionally contain various other ingredients known in the art, for example, a lubricant, stabilising agent, buffering agent, emulsifying agent, viscosity-regulating agent, surfactant, preservative, flavouring or colorant.
  • a lubricant for example, a lubricant, stabilising agent, buffering agent, emulsifying agent, viscosity-regulating agent, surfactant, preservative, flavouring or colorant.
  • Unit dosage form refers to physically discrete units suitable as unitary dosages, each unit containing a predetermined quantity of active ingredient calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier.
  • unit dosage forms are tablets (including scored or coated tablets), capsules, pills, powder packets, wafers, suppositories, injectable solutions or suspensions and the like, and segregated multiples thereof.
  • the daily dosage of the compound according to the invention will, of course, vary with the compound employed, the mode of administration, the treatment desired and the mycobacterial disease indicated. However, in general, satisfactory results will be obtained when the compound according to the invention is administered at a daily dosage not exceeding 1 gram, e.g. in the range from 10 to 50 mg/kg body weight.
  • the present compounds may be combined with other antibacterial agents in order to effectively combat bacterial infections.
  • compounds may be useful against bacterial infections, we mean that those compounds may have activity as such or those compounds may be effective in combination (as described herein, e.g. with one or more other inhibitors of the electron transport chain of mycobacteria) by enhancing activity or providing synergistic combinations, for example as may be described in the experimental hereinafter.
  • the present invention also relates to a combination of (a) a compound according to the invention, and (b) one or more other antibacterial agents (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor).
  • a compound according to the invention and (b) one or more other antibacterial agents (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor).
  • the present invention also relates to such a compound or combination, for use as a medicine.
  • the present invention also relates to the use of a combination or pharmaceutical composition as defined directly above for the treatment of a bacterial infection.
  • a pharmaceutical composition comprising a pharmaceutically acceptable carrier and, as active ingredient, a therapeutically effective amount of (a) a compound according to the invention, and (b) one or more other antibacterial agents (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor), is also comprised by the present invention.
  • one or more other antibacterial agents e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor
  • the weight ratio of (a) the compound according to the invention and (b) the other antibacterial agent(s) when given as a combination may be determined by the person skilled in the art. Said ratio and the exact dosage and frequency of administration depends on the particular compound according to the invention and the other antibacterial agent(s) used, the particular condition being treated, the severity of the condition being treated, the age, weight, gender, diet, time of administration and general physical condition of the particular patient, the mode of administration as well as other medication the individual may be taking, as is well known to those skilled in the art. Furthermore, it is evident that the effective daily amount may be lowered or increased depending on the response of the treated subject and/or depending on the evaluation of the physician prescribing the compounds of the instant invention. A particular weight ratio for the present compound of the invention and another antibacterial agent may range from 1/10 to 10/1, more in particular from 1/5 to 5/1, even more in particular from 1/3 to 3/1.
  • the compounds according to the invention and the one or more other antibacterial agents may be combined in a single preparation or they may be formulated in separate preparations so that they can be administered simultaneously, separately or sequentially.
  • the present invention also relates to a product containing (a) a compound according to the invention, and (b) one or more other antibacterial agents (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor), as a combined preparation for simultaneous, separate or sequential use in the treatment of a bacterial infection.
  • one or more other antibacterial agents e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as
  • antibacterial agents which may be combined with the compounds of the invention are for example antibacterial agents known in the art.
  • the compounds of the invention may be combined with antibacterial agents known to interfere with the respiratory chain of Mycobacterium tuberculosis, including for example direct inhibitors of the ATP synthase (e.g. bedaquiline, bedaquiline fumarate or any other compounds that may have be disclosed in the prior art, e.g. compounds disclosed in W02004/011436), inhibitors of ndh2 (e.g. clofazimine) and inhibitors of cytochrome bd.
  • direct inhibitors of the ATP synthase e.g. bedaquiline, bedaquiline fumarate or any other compounds that may have be disclosed in the prior art, e.g. compounds disclosed in W02004/011436
  • inhibitors of ndh2 e.g. clofazimine
  • inhibitors of cytochrome bd e.g. cytochrome bd.
  • compounds of the invention may be combined with one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor.
  • a cytochrome be inhibitor for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor.
  • the compounds of the invention might act as cytochrome bd inhibitors, and hence target the electron transport chain of the mycobacteria (thereby blocking energy production of mycobacteria), the compounds of the invention (cytochrome bd inhibitors), combinations with one or more other inhibitors of the electron transport chain is thought to be a potentially effective way of providing an efficient regimen against mycobacteria. Even if the compounds of the invention (cytochrome bd inhibitors) alone might not be effective against mycobacteria, combining with one or more other such inhibitors may provide an effective regimen where the activity of one or more components of the combination is/are enhanced and/or such combinations act more effectively (e.g. synergistically).
  • the compounds according to the invention can generally be prepared by a succession of steps, each of which may be known to the skilled person or described herein.
  • Compounds of formula (I) may be prepared by: (i) hydrogenation of a compound of formula (V), in which the integers are hereinbefore defined, by reaction with an appropriate reagent such as Hi and a palladium on carbon catalyst (for example, as described in the examples).
  • reaction products may be isolated from the reaction medium and, if necessary, further purified according to methodologies generally known in the art, such as extraction, crystallization and chromatography. It is further evident that reaction products that exist in more than one enantiomeric form, may be isolated from their mixture by known techniques, in particular preparative chromatography, such as preparative HPLC, chiral chromatography. Individual diastereoisomers or individual enantiomers can also be obtained by Supercritical Fluid Chromatography (SCF).
  • SCF Supercritical Fluid Chromatography
  • reaction products may be isolated from the reaction medium and, if necessary, further purified according to methodologies generally known in the art, such as extraction, crystallization and chromatography. It is further evident that reaction products that exist in more than one enantiomeric form, may be isolated from their mixture by known techniques, in particular preparative chromatography, such as preparative HPLC, chiral chromatography. Individual diastereoisomers or individual enantiomers can also be obtained by Supercritical Fluid Chromatography (SCF).
  • SCF Supercritical Fluid Chromatography
  • the starting materials and the intermediates are compounds that are either commercially available or may be prepared according to conventional reaction procedures generally known in the art.
  • 8QD means Single Quadrupole Detector, “RT” room temperature, “BEH” bridged ethylsiloxane/silica hybrid, “HSS” High Strength Silica, “DAD” Diode Array Detector, “MSD” Mass Selective Detector.
  • RuPhos Pd G3 (2-Dicyclohexylphosphino-2',6'-diisopropoxy- 1,1'- biphenyl)[2-(2'-amino-l, 1 '-biphenyl)] palladium(II) methanesulfonate t-AmylOH tert- Amyl alcohol
  • the emulsion formed was concentrated under reduced pressure to remove DCM.
  • the residue was taken in water, filtered and washed with water (500 mL).
  • the solid was dissolved in DCM (250 mL), dried over NaiSCL, filtered and concentrated to dryness under reduced pressure.
  • the residue was purified by flash chromatography over silica gel (cartridge: Interchim IR50SI F0800, eluent: DCM/EtOAc from 100/0 to 70/30 over 40 min) to afford intermediate 11 (15.8 g, 90%) as a black solid.
  • Hexamethylditin [661-69-8] (0.9 mL, 4.34 mmol) was added to 2- Bromo-5-(trifluoromethoxy)pyridine [888327-36-4] (1.38 g, 5.42 mmol), and Tetrakis(triphenylphosphine)palladium(0) [14221-01-3] (0.63 g, 0.54 mmol), in Dry Toluene (27 mL) after bubbling the mixture with nitrogen for 10 minutes.
  • the reaction mixture was heated at 100 °C for 16 h. LCMS showed complete conversion into the desired product and no starting material. Yielding intermediate 22.
  • the reaction mixture was used in the next step without any work-up or further purification.
  • intermediate 32 (1.155 g, 3.979 mmol), intermediate 25 (539 mg, 1.989 mmol) and potassium carbonate [584-08-7] (412 mg, 2.98 mmol, 1.5 equiv.) were added in dry dioxane (120 mL). The mixture was deoxygenated by bubbling nitrogen for 2 min.
  • intermediate 24 (610 mg, 1.56 mmol) was added to a mixture of 3- methyl-4-oxo-lH-quinoline-2-carboxylic acid [CAS: 402491-58-1] (212 mg, 1.04 mmol), EDC hydrochloride acid [CAS: 25952-53-8] (240 mg, 1.25 mmol), and Pyridine (11 mL, 136 mmol) at rt.
  • the mixture was stirred at 90 °C for 16 h. LCMS analysis showed desired product.
  • 10% Pd/C (190 mg, 0. 16 mmol) was added to a solution of intermediate 4 (1.09 g, 2.5 mmol) in EtOH (20 mL) and EtOAc (20 mL) under nitrogen atmosphere at 0 °C. The mixture was stirred under 3 ⁇ 4 atmospheric pressure at rt for 16 h. Then, the reaction mixture was stirred at 60 °C for 8 h and at 50 °C for 16 h. Then, additional amount of 10% Pd/C ( 190 mg, 0.16 mmol) was added and the mixture was stirred at 60 °C for 8 h and at 50 °C for 16 h.
  • the reaction was filtered through a pad of celite®, washed with DCM/MeOH (50v/50v) and solvents were evaporated in vacuo.
  • the crude was purified by flash column chromatography (dry load in silica; DCM/MeOH (20: 1) in DCM from 0/100 to 60/40). The desired factions were collected and concentrated in vacuo to yield a first fraction of compound 1 (119 mg, 11%, 98% pure) and a second fraction of compound 1 (380 mg, 31%, 90% pure) as beige solids.
  • the mixture was hydrogenated (atmospheric pressure) at 60 °C for 20 h.
  • the reaction was filtered through a pad of celite® and the solvents were evaporated in vacuo.
  • the crude was purified by flash column chromatography (dry load in silica; DCM/MeOH (9:1) in DCM from 0/100 to 50/50). The desired factions were collected and concentrated in vacuo to yield compound 2 (137 mg, 26%) as a white solid.
  • Compound X is 6-chloro-2-ethyl-/V-( ⁇ 4-[2-(trifluoromethanesulfonyl)-2- azaspiro[3.3]heptan-6-yl]phenyl ⁇ methyl)imidazo[ 1 ,2- ⁇ ]pyridine-3-carboxamide, which is described as Compound 154 of WO 2017/001660 and may be prepared according to the procedures described therein.
  • CK-2-63 may be prepared in accordance with the procedures disclosed in WO 2017/103615 (see experimental and the disclosures therein, referring to WO 2012/2069856, where an experimental procedure is provided for “3-methyl-2-(4-(4- (trifluoromethoxy)phenoxy)phenyl)quinolin-4(lH)-one”).
  • Test compounds and reference compounds were dissolved in DMSO and 1 m ⁇ of solution was spotted per well in 96 well plates at 200x the final concentration. Column 1 and column 12 were left compound-free, and from column 2 to 11 compound concentration was diluted 3-fold. Frozen stocks of Mycobacterium tuberculosis strain EH4.0 expressing green-fluorescent protein (GFP) were previously prepared and titrated. To prepare the inoculum, 1 vial of frozen bacterial stock was thawed to room temperature and diluted to 5x10 exp5 colony forming units per ml in 7H9 broth. 200 m ⁇ of inoculum, which corresponds to 1x10 exp5 colony forming units, were transferred per well to the whole plate, except column 12.
  • GFP green-fluorescent protein
  • fluorescence was measured on a Gemini EM Microplate Reader with 543 excitation and 590 nm emission wavelengths and MIC50 and/or pICso values (or the like, e.g. IC50, IC90, PIC90, etc) were (or may be) calculated.
  • Bactericidal or bacteriostatic activity of the compounds can be determined in a time kill kinetic assay using the broth dilution method.
  • the starting inoculum of M. tuberculosis (strain H37Rv and H37Ra) is 10 6 CFU / ml in Middlebrook (lx) 7H9 broth.
  • the test compounds (cyt bd inhibitors) are tested in combination with a cyt be inhibitor (for example Q203 or Compound X) at the concentration ranging from 10- 30mM to 0.9-0.3mM respectively.
  • Tubes receiving no antibacterial agent constitute the culture growth control.
  • the tubes containing the microorganism and the test compounds are incubated at 37 °C.
  • the aim of this assay is to evaluate the O2 consumption rate of Mycobacterium tuberculosis (Mtb) bacilli after inhibition of cyt bcl and cyt bd, using extracellular flux technology.
  • Inhibition of cyt bcl e.g. using known inhibitors such as Q203 or Compound X
  • the inhibition of cyt bd will cause a significant decrease O2 consumption.
  • a sustained decrease of O2 consumption under membrane potential disrupting conditions, via the addition of the uncoupler CCCP, will show to the efficacy of the cyt bd inhibitor.
  • OCR oxygen consumption rate
  • the Compound X (final concentration of 0.9 mM, Compound X), is used to inhibit cyt bcl and the cyt bd inhibitor, CK-2-63 (final concentration of 10 mM), is used as a positive control.
  • the uncoupler CCCP is used at a final concentration of 1 mM.
  • Phenotypic assay using a cytochrome be knock-out TB strain and MIC determination against M. tuberculosis ⁇ , test 5
  • Biological Data - Example A Compounds of the invention/examples (or combinations, e.g. compounds of the invention/examples in combination with one or more other inhibitors of a target of the electron transport chain), for example when tested in any of Tests 1 to 3, may display activity.
  • Biological Data - Example B Compounds of the invention/examples (or combinations, e.g. compounds of the invention/examples in combination with one or more other inhibitors of a target of the electron transport chain), for example when tested in any of Tests 1 to 3, may display activity.
  • Biological Data - Example B Compounds of the invention/examples (or combinations, e.g. compounds of the invention/examples in combination with one or more other inhibitors of a target of the electron transport chain), for example when tested in any of Tests 1 to 3, may display activity.
  • Biological Data - Example B Compounds of the invention/examples (or combinations, e.g. compounds of the invention/example
  • the compounds of the invention/examples may have advantages associated with in vitro potency, kill kinetics (i.e. bactericidal effect) in vitro, PK properties, food effect, safety/toxicity (including liver toxicity, coagulation, 5-LO oxygenase), metabolic stability, Ames II negativity, MNT negativity, aqueous based solubility (and ability to formulate) and/or cardiovascular effect e.g. on animals (e.g. anesthetized guinea pig).
  • the data below that was generated/calculated may be obtained using standard methods/assays, for instance that are available in the literature or which may be performed by a supplier (e.g. Microsomal Stability Assay - Cyprotex, Mitochondrial toxicity (Glu/Gal) assay - Cyprotex, as well as literature CYP cocktail inhibition assays).
  • compounds of the invention/examples may be found to be advantageous as no mitotoxicity alerts were observed (e.g. in the Glu/Gal assay).

Abstract

The present invention relates to the following compounds (I) wherein the integers are as defined in the description, and where the compounds may be useful as medicaments, for instance for use in the treatment of tuberculosis (e.g. in combination).

Description

ANTIB ACTERIAL COMPOUNDS
The present invention relates to novel compounds. The invention also relates to such compounds for use as a pharmaceutical and further for the use in the treatment of bacterial diseases, including diseases caused by pathogenic mycobacteria such as Mycobacterium tuberculosis. Such compounds may work by targeting the respiratory chain, and thereby blocking all energy production of mycobacteria. There are several ways of targeting the electron transport chain of mycobacteria, for instance by interfering with ATP synthase in M. tuberculosis. This particular invention focuses on the cytochrome bd target of the respiratory chain, which may be the primary mode of action. Hence, primarily, such compounds are antitubercular agents, and in particular may act as such when combined with another tuberculosis drug (e.g. another inhibitor of a different target of the electron transport chain).
BACKGROUND OF THE INVENTION
Mycobacterium tuberculosis is the causative agent of tuberculosis (TB), a serious and potentially fatal infection with a world-wide distribution. Estimates from the World Health Organization indicate that more than 8 million people contract TB each year, and 2 million people die from tuberculosis yearly. In the last decade, TB cases have grown 20% worldwide with the highest burden in the most impoverished communities. If these trends continue, TB incidence will increase by 41% in the next twenty years. Fifty years since the introduction of an effective chemotherapy, TB remains after AIDS, the leading infectious cause of adult mortality in the world. Complicating the TB epidemic is the rising tide of multi-drug-resistant strains, and the deadly symbiosis with HIV. People who are HIV-positive and infected with TB are 30 times more likely to develop active TB than people who are HIV-negative and TB is responsible for the death of one out of every three people with HIV/AIDS worldwide.
Existing approaches to treatment of tuberculosis all involve the combination of multiple agents. For example, the regimen recommended by the U.S. Public Health Service is a combination of isoniazid, rifampicin and pyrazinamide for two months, followed by isoniazid and rifampicin alone for a further four months. These drugs are continued for a further seven months in patients infected with HIV. For patients infected with multidrug resistant strains of M. tuberculosis, agents such as ethambutol, streptomycin, kanamycin, amikacin, capreomycin, ethionamide, cycloserine, ciprofoxacin and ofloxacin are added to the combination therapies. There exists no single agent that is effective in the clinical treatment of tuberculosis, nor any combination of agents that offers the possibility of therapy of less than six months’ duration.
There is a high medical need for new drugs that improve current treatment by enabling regimens that facilitate patient and provider compliance. Shorter regimens and those that require less supervision are the best way to achieve this. Most of the benefit from treatment comes in the first 2 months, during the intensive, or bactericidal, phase when four drugs are given together; the bacterial burden is greatly reduced, and patients become noninfectious. The 4- to 6-month continuation, or sterilizing, phase is required to eliminate persisting bacilli and to minimize the risk of relapse. A potent sterilizing drug that shortens treatment to 2 months or less would be extremely beneficial. Drugs that facilitate compliance by requiring less intensive supervision also are needed. Obviously, a compound that reduces both the total length of treatment and the frequency of drug administration would provide the greatest benefit.
Complicating the TB epidemic is the increasing incidence of multi-drug-resistant strains or MDR-TB. Up to four percent of all cases worldwide are considered MDR-TB - those resistant to the most effective drugs of the four-drug standard, isoniazid and rifampin. MDR-TB is lethal when untreated and cannot be adequately treated through the standard therapy, so treatment requires up to 2 years of "second-line" drugs. These drugs are often toxic, expensive and marginally effective. In the absence of an effective therapy, infectious MDR-TB patients continue to spread the disease, producing new infections with MDR-TB strains. There is a high medical need for a new drug with a new mechanism of action, which is likely to demonstrate activity against drug resistant, in particular MDR strains.
The term “drug resistant” as used hereinbefore or hereinafter is a term well understood by the person skilled in microbiology. A drug resistant Mycobacterium is a Mycobacterium which is no longer susceptible to at least one previously effective drug; which has developed the ability to withstand antibiotic attack by at least one previously effective drug. A drug resistant strain may relay that ability to withstand to its progeny. Said resistance may be due to random genetic mutations in the bacterial cell that alters its sensitivity to a single drug or to different drugs.
MDR tuberculosis is a specific form of drug resistant tuberculosis due to a bacterium resistant to at least isoniazid and rifampicin (with or without resistance to other drugs), which are at present the two most powerful anti-TB drugs. Thus, whenever used hereinbefore or hereinafter “drug resistant” includes multi drug resistant. Another factor in the control of the TB epidemic is the problem of latent TB. In spite of decades of tuberculosis (TB) control programs, about 2 billion people are infected by M. tuberculosis, though asymptomatically. About 10% of these individuals are at risk of developing active TB during their lifespan. The global epidemic of TB is fuelled by infection of HIV patients with TB and rise of multi-drug resistant TB strains (MDR-TB). The reactivation of latent TB is a high risk factor for disease development and accounts for 32% deaths in HIV infected individuals. To control TB epidemic, the need is to discover new drugs that can kill dormant or latent bacilli. The dormant TB can get reactivated to cause disease by several factors like suppression of host immunity by use of immunosuppressive agents like antibodies against tumor necrosis factor a or interferon-g. In case of HIV positive patients the only prophylactic treatment available for latent TB is two- three months regimens of rifampicin, pyrazinamide. The efficacy of the treatment regime is still not clear and furthermore the length of the treatments is an important constrain in resource-limited environments. Hence there is a drastic need to identify new drugs, which can act as chemoprophylatic agents for individuals harboring latent TB bacilli.
The tubercle bacilli enter healthy individuals by inhalation; they are phagocytosed by the alveolar macrophages of the lungs. This leads to potent immune response and formation of granulomas, which consist of macrophages infected with M. tuberculosis surrounded by T cells. After a period of 6-8 weeks the host immune response cause death of infected cells by necrosis and accumulation of caseous material with certain extracellular bacilli, surrounded by macrophages, epitheloid cells and layers of lymphoid tissue at the periphery. In case of healthy individuals, most of the mycobacteria are killed in these environments but a small proportion of bacilli still survive and are thought to exist in a non-replicating, hypometabolic state and are tolerant to killing by anti-TB drugs like isoniazid. These bacilli can remain in the altered physiological environments even for individual’s lifetime without showing any clinical symptoms of disease. However, in 10% of the cases these latent bacilli may reactivate to cause disease. One of the hypothesis about development of these persistent bacteria is patho-physiological environment in human lesions namely, reduced oxygen tension, nutrient limitation, and acidic pH. These factors have been postulated to render these bacteria phenotypically tolerant to major anti-mycobacterial drugs.
In addition to the management of the TB epidemic, there is the emerging problem of resistance to first-line antibiotic agents. Some important examples include penicillin- resistant Streptococcus pneumoniae, vancomycin-resistant enterococci, methicillin- resistant Staphylococcus aureus, multi-resistant salmonellae.
The consequences of resistance to antibiotic agents are severe. Infections caused by resistant microbes fail to respond to treatment, resulting in prolonged illness and greater risk of death. Treatment failures also lead to longer periods of infectivity, which increase the numbers of infected people moving in the community and thus exposing the general population to the risk of contracting a resistant strain infection.
Hospitals are a critical component of the antimicrobial resistance problem worldwide. The combination of highly susceptible patients, intensive and prolonged antimicrobial use, and cross-infection has resulted in infections with highly resistant bacterial pathogens.
Self-medication with antimicrobials is another major factor contributing to resistance. Self-medicated antimicrobials may be unnecessary, are often inadequately dosed, or may not contain adequate amounts of active drug.
Patient compliance with recommended treatment is another major problem. Patients forget to take medication, interrupt their treatment when they begin to feel better, or may be unable to afford a full course, thereby creating an ideal environment for microbes to adapt rather than be killed.
Because of the emerging resistance to multiple antibiotics, physicians are confronted with infections for which there is no effective therapy. The morbidity, mortality, and financial costs of such infections impose an increasing burden for health care systems worldwide.
Therefore, there is a high need for new compounds to treat bacterial infections, especially mycobacteria] infections including drug resistant and latent mycobacterial infections, and also other bacterial infections especially those caused by resistant bacterial strains.
There are several ways of targeting the electron transport chain of mycobacteria, for instance by interfering with ATP synthase in M. tuberculosis. Unlike many bacteria,
M. tuberculosis is dependent on respiration to synthesise adequate amounts of ATP. Hence targeting the electron transport chain of the mycobacteria and thereby blocking energy production of mycobacteria is thought to be a potentially effective way of providing an efficient regimen against mycobacteria. Targets already known are ATP synthase inhibitors, as example of which is bedaquiline (marketed as Sirturo®), cytochrome he inhibitors, examples of which include the compound Q203 described in Journal article Nature Medicine, 19, 1157-1160 (2013) by Pethe et al “Discovery of Q203, a potent clinical candidate for the treatment of tuberculosis”, as well as patent applications such as internataional patent applcations WO 2017/001660, WO 2017/001661 , WO 2017/216281 and WO 2017/216283.
Additionally, journal article Antimicrob. Agents Chemother, 2014, 6962-6965 by Arora et al describes compounds that target the respiratory bci complex in M. tuberculosis, and where deletion of the cytochrome bd oxidase generated a hypersusceptible mutant. Journal article PANS (Early Edition), 2017, “Exploiting the synthetic lethality between terminal respiratory oxidases to kill Mycobacterium tuberculosis and clear host infection” by Kalia et al discloses various data around various tuberculosis compounds that target the respiratory chain. For instance, it is shown that the compound Q203 (a known be inhibitor; see above) could inhibit mycobacteria completely and become bactericidal, after genetic deletion of the cytochrome bd oxidase-encoding genes CydAB. Similarly, journal article MBio, 2014 Jul 15 ;5(4) by Berney et al “A Mycobacterium tuberculosis cytochrome bd oxidase mutant is hypersensitive to bedaquiline” shows that the activity of bedaquiline is enhanced when bd is inactiviated.
One known cytochrome bd inhibitor is Aurachin D, which is a quinolone with a realtively long side-chain. Cytochrome bd itself is not essential for aerobic growth, but is upregulated and protects against a variety of stresses in various bacterial strains, for example as described in journal article Biochimica et Biophysica Acta 1837 (2014)
1178- 1187 by Giuffre et al. Hence, monotherapy with a cytochrome bd inhibitor would not necessarily be expected to inhibit mycobacteria growth, but a combination with another inihibitor of a target of the electron transport chain of mycobacteria could be.
Various compounds are described in international patent applications WO 2012/069856 and WO 2017/103615, with the latter application describing such compounds as cytochrome bd inhibitors and indicates that thereapeutic combination products comprising one or more respiratory electron transport chain inhibitor and a cytochrome bd inhibitor is disclosed. Specifically, the compound CK-2-63 is described as a cytochrome bd inhibitor showing various inhibitor activity data, and combination data is also disclosed including combination of CK-2-63 with a mycobacterium cytochrome bcc inhibitor (e.g. AWE-402, where it is indicated therein that it is structurally related to the cytochrome bcc inhibitor Q203). It is indicated that such dual combination led to in increase in mycobacteria kill. It also described a combination of bedaquiline (a known ATP synthase inhibitor) with CK-2-63, and it is indicated that CK-2-63 showed an enhancement of bedaquiline activity at low concentrations. Data around a triple combination of bedaquiline, AWE-402 (a be inhibitor; see above) and CK-2-63 is also shown.
This particular invention focuses on novel compounds of the cytochrome bd target of the respiratory chain. New alternative/improved compounds are required, which may be tested/employed for use in combination.
SUMMARY OF THE INVENTION There is now provided a compound of formula (I)
Figure imgf000007_0001
wherein
R1 represents Ci-6 alkyl, -Br, hydrogen or -C(0)N(Rql)Rq2;
Rql and Rq2 independently represent hydrogen or Ci-6 alkyl, or may be linked together to form a 3-6 membered carbocylic ring optionally substituted by one or more C 1-3 alkyl substituents;
Sub represents one or more optional substituents selected from halo (e.g, fluoro), -CN, C1-6 alkyl and -O-Ci^ alkyl (wherein the latter two alkyl moieties are optionally substituted by one or more fluoro atoms); the “A” ring represents a 6-membered ring which may be aromatic or non-aromatic, or it represents a 5-membered aromatic ring containing one heteroatom (e.g. a sulfur heteroatom); the “B” ring represents a 5-membered heteroaryl ring, which contains between one and four heteroatoms (e.g. selected from nitrogen, oxygen and sulfur), and which “B” ring is optionally substituted by one or more substituents selected from halo and C1-6 alkyl (itself optionally substituted by one or more fluoro atoms);
L1 represents an optional linker group, and hence may be a direct bond or -C(Rxl)(Rx2);
Rxl and Rx2 independently represent hydrogen or C 1 -3 alkyl;
Figure imgf000008_0001
ring C represents a 5-membered aromatic ring containing at least one heteroatom (preferably containing at least one nitrogen atom), and which ring is optionally substituted by one or more substituents independently selected from Rf; ring D represents a 6-membered aromatic ring containing at least one heteroatom (preferably containing at least one nitrogen atom), and which ring is optionally substituted by one or more substituents independently selected from Rg;
Yb represents -[(CH2)i-4]~ (so forming a 3- to 6-membered N-containing ring), and Rh represents one or more optional substituents on such ring;
Ra, Rb, Rc, Rd and Re independently represent hydrogen or a substituent selected from B1; each Rf, each Rs and each Rh (which are optional substituents), when present, independently represent a substituent selected from B1; each B1 independently represents a substituent selected from:
Figure imgf000009_0001
Rdl represents Cue alkyl, preferably C1-3 alkyl, optionally substituted by one or more halo (e.g. fluoro) atoms; Rel, Re2, Re3, Re4 and Re5 each independently represent hydrogen or Cue alkyl optionally substituted by one or more fluoro atoms; or a pharmaceutically-acceptable salt thereof, which compounds may be referred to herein as “compounds of the invention”.
In a particular embodiment, compounds of the invention include those described here (e.g. above), in which: each B1 independently represents a substituent selected from:
Figure imgf000010_0001
Pharmaceutically-acceptable salts include acid addition salts and base addition salts. Such salts may be formed by conventional means, for example by reaction of a free acid or a free base form of a compound of formula 1 with one or more equivalents of an appropriate acid or base, optionally in a solvent, or in a medium in which the salt is insoluble, followed by removal of said solvent, or said medium, using standard techniques (e.g. in vacuo, by freeze-drying or by filtration). Salts may also be prepared by exchanging a counter-ion of a compound of the invention in the form of a salt with another counter-ion, for example using a suitable ion exchange resin.
The pharmaceutically acceptable acid addition salts as mentioned hereinabove are meant to comprise the therapeutically active non-toxic acid addition salt forms that the compounds of formula (I) are able to form. These pharmaceutically acceptable acid addition salts can conveniently be obtained by treating the base form with such appropriate acid. Appropriate acids comprise, for example, inorganic acids such as hydrohalic acids, e.g. hydrochloric or hydrobromic acid, sulfuric, nitric, phosphoric and the like acids; or organic acids such as, for example, acetic, propanoic, hydroxyacetic, lactic, pyruvic, oxalic (i.e. ethanedioic), malonic, succinic (i.e. butanedioic acid), maleic, fumaric, malic, tartaric, citric, methanesulfonic, ethanesulfonic, benzenesulfonic, p-toluenesulfonic, cyclamic, salicylic, p-aminosalicylic, pamoic and the like acids. For the purposes of this invention solvates, prodrugs, N-oxides and stereoisomers of compounds of the invention are also included within the scope of the invention. The term “prodrug” of a relevant compound of the invention includes any compound that, following oral or parenteral administration, is metabolised in vivo to form that compound in an experimentally-detectable amount, and within a predetermined time (e.g. within a dosing interval of between 6 and 24 hours (i.e. once to four times daily)).
For the avoidance of doubt, the term “parenteral” administration includes all forms of administration other than oral administration.
Prodrugs of compounds of the invention may be prepared by modifying functional groups present on the compound in such a way that the modifications are cleaved, in vivo when such prodrug is administered to a mammalian subject. The modifications typically are achieved by synthesising the parent compound with a prodrug substituent. Prodrugs include compounds of the invention wherein a hydroxyl, amino, sulfhydryl, carboxy or carbonyl group in a compound of the invention is bonded to any group that may be cleaved in vivo to regenerate the free hydroxyl, amino, sulfhydryl, carboxy or carbonyl group, respectively.
Examples of prodrugs include, but are not limited to, esters and carbamates of hydroxy functional groups, esters groups of carboxyl functional groups, N-acyl derivatives and N-Mannich bases. General information on prodrugs may be found e.g. in Bundegaard, H. “Design of Prodrugs” p. 1-92, Elesevier, New York-Oxford (1985).
Compounds of the invention may contain double bonds and may thus exist as E ( entgegen ) and Z ( zusammen ) geometric isomers about each individual double bond. Positional isomers may also be embraced by the compounds of the invention. All such isomers (e.g. if a compound of the invention incorporates a double bond or a fused ring, the cis- and trans- forms, are embraced) and mixtures thereof are included within the scope of the invention (e.g. single positional isomers and mixtures of positional isomers may be included within the scope of the invention).
Compounds of the invention may also exhibit tautomerism. All tautomeric forms (or tautomers) and mixtures thereof are included within the scope of the invention. The term "tautomer" or "tautomeric form" refers to structural isomers of different energies which are interconvertible via a low energy barrier. For example, proton tautomers (also known as prototropic tautomers) include interconversions via migration of a proton, such as keto-enol and imine-enamine isomerisations. Valence tautomers include interconversions by reorganisation of some of the bonding electrons. Compounds of the invention may also contain one or more asymmetric carbon atoms and may therefore exhibit optical and/or diastereoisomerism. Diastereoisomers may be separated using conventional techniques, e.g. chromatography or fractional crystallisation. The various stereoisomers may be isolated by separation of a racemic or other mixture of the compounds using conventional, e.g. fractional crystallisation or HPLC, techniques. Alternatively the desired optical isomers may be made by reaction of the appropriate optically active starting materials under conditions which will not cause racemisation or epimerisation (i.e. a ‘chiral pool’ method), by reaction of the appropriate starting material with a ‘chiral auxiliary’ which can subsequently be removed at a suitable stage, by derivatisation (i.e. a resolution, including a dynamic resolution), for example with a homochiral acid followed by separation of the diastereomeric derivatives by conventional means such as chromatography, or by reaction with an appropriate chiral reagent or chiral catalyst all under conditions known to the skilled person.
All stereoisomers (including but not limited to diastereoisomers, enantiomers and atropisomers) and mixtures thereof (e.g. racemic mixtures) are included within the scope of the invention.
In the structures shown herein, where the stereochemistry of any particular chiral atom is not specified, then all stereoisomers are contemplated and included as the compounds of the invention. Where stereochemistry is specified by a solid wedge or dashed line representing a particular configuration, then that stereoisomer is so specified and defined.
The compounds of the present invention may exist in unsolvated as well as solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like, and it is intended that the invention embrace both solvated and unsolvated forms.
The present invention also embraces isotopically-labeled compounds of the present invention which are identical to those recited herein, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature (or the most abundant one found in nature). All isotopes of any particular atom or element as specified herein are contemplated within the scope of the compounds of the invention. Exemplary isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, fluorine, chlorine and iodine, such as 2H, 3H, "C 13C, 14C , 13N, 'Ό. 170, ISO, 32P, 33P, 35S, 18F, 36C1, l23I, and l25I. Certain isotopically-labeled compounds of the present invention (e.g., those labeled with 3H and 14C) are useful in compound and for substrate tissue distribution assays. Tritiated (3H) and carbon-14 (l4C) isotopes are useful for their ease of preparation and detectability. Further, substitution with heavier isotopes such as deuterium (i.e., 2H may afford certain therapeutic advantages resulting from greater metabolic stability (e.g., increased in vivo half-life or reduced dosage requirements) and hence may be preferred in some circumstances. Positron emitting isotopes such as l50, l3N, nC and 18F are usefuI for positron emission tomography (PET) studies to examine substrate receptor occupancy. Isotopically labeled compounds of the present invention can generally be prepared by following procedures analogous to those disclosed in the description/Examples hereinbelow, by substituting an isotopically labeled reagent for a non-isotopieally labeled reagent.
Unless otherwise specified, Cu4 alkyl groups (where q is the upper limit of the range) defined herein may be straight-chain or, when there is a sufficient number (i.e. a minimum of two or three, as appropriate) of carbon atoms, be branched-chain, and/or cyclic (so forming a Cs-q-cycloalkyl group). Such cycloalkyl groups may be monocyclic or bicyclic and may further be bridged. Further, when there is a sufficient number (i.e. a minimum of four) of carbon atoms, such groups may also be part cyclic. Such alkyl groups may also be saturated or, when there is a sufficient number (i.e. a minimum of two) of carbon atoms, be unsaturated (forming, for example, a C2-q alkenyl or a C2-q alkynyl group).
C3-q cycloalkyl groups (where q is the upper limit of the range) that may be specifically mentioned may be monocyclic or bicyclic alkyl groups, which cycloalkyl groups may further be bridged (so forming, for example, fused ring systems such as three fused cycloalkyl groups). Such cycloalkyl groups may be saturated or unsaturated containing one or more double bonds (forming for example a cycloalkenyl group). Substituents may be attached at any point on the cycloalkyl group. Further, where there is a sufficient number (i.e. a minimum of four) such cycloalkyl groups may also be part cyclic.
The term “halo”, when used herein, preferably includes fluoro, chloro, bromo and iodo.
Heterocyclic groups when referred to herein may include aromatic or non-aromatic heterocyclic groups, and hence encompass heterocycloalkyl and hetereoaryl. Equally, “ aromatic or non-aromatic 5- or 6-membered rings” may be heterocyclic groups (as well as carbocyclic groups) that have 5- or 6-members in the ring.
Heterocycloalkyl groups that may be mentioned include non-aromatic monocyclic and bicyclic heterocycloalkyl groups in which at least one (e.g. one to four) of the atoms in the ring system is other than carbon (i.e. a heteroatom), and in which the total number of atoms in the ring system is between 3 and 20 (e.g. between three and ten, e.g between 3 and 8, such as 5- to 8-). Such heterocycloalkyl groups may also be bridged. Further, such heterocycloalkyl groups may be saturated or unsaturated containing one or more double and/or triple bonds, forming for example a C?-q heterocycloalkenyl (where q is the upper limit of the range) group. C2-q heterocycloalkyl groups that may be mentioned include 7-azabicyclo[2,2.1]heptanyl, 6-azabicyclo[3.1.1]heptanyl, 6- azabicyclo[3.2.1]-octanyl, 8-azabicyclo-[3.2. ljoctanyl, aziridinyl, azetidinyl, dihydropyranyl, dihydropyridyl, dihydropyrrolyl (including 2,5-dihydropyrrolyl), dioxolanyl (including 1 ,3-dioxolanyl), dioxanyl (including 1,3-dioxanyl and 1,4- dioxanyl), dithianyl (including 1 ,4-dithianyl), dithiolanyl (including 1,3-dithiolanyl), imidazolidinyl, imidazolinyl, morpholinyl, 7-oxabicyclo[2.2.1]heptanyl, 6-oxabicyclo- [3.2.1]octanyl, oxetanyl, oxiranyl, piperazinyl, piperidinyl, non-aromatic pyranyl, pyrazolidinyl, pyrrolidinonyl, pyrrolidinyl, pyrrolinyl, quinuclidinyl, sulfolanyl, 3- sulfolenyl, tetrahydropyranyl, tetrahydrofuranyl, tetrahydropyridyl (such as 1 ,2,3,4- tetrahydropyridyl and 1,2,3,6-tetrahydropyridyl), thietanyl, thiiranyl, thiolanyl, thiomorpholinyl, trithianyl (including 1,3,5-trithianyl), tropanyl and the like. Substituents on heterocycloalkyl groups may, where appropriate, be located on any atom in the ring system including a heteroatom. The point of attachment of heterocycloalkyl groups may be via any atom in the ring system including (where appropriate) a heteroatom (such as a nitrogen atom), or an atom on any fused carbocyclic ring that may be present as part of the ring system. Heterocycloalkyl groups may also be in the N- or S- oxidised form. Heterocycloalkyl mentioned herein may be stated to be specifically monocyclic or bicyclic.
Aromatic groups may be aryl or heteroaryl. Aryl groups that may be mentioned include Ce-20, such as Ce-i2 (e.g. Ce-io) aryl groups. Such groups may be monocyclic, bicyclic or tricyclic and have between 6 and 12 (e.g. 6 and 10) ring carbon atoms, in which at least one ring is aromatic. Ceuo aryl groups include phenyl, naphthyl and the like, such as 1,2,3,4-tetrahydronaphthyl. The point of attachment of aryl groups may be via any atom of the ring system. For example, when the aryl group is polycyclic the point of attachment may be via atom including an atom of a non-aromatic ring. However, when aryl groups are polycyclic (e.g. bicyclic or tricyclic), they are preferably linked to the rest of the molecule via an aromatic ring. Most preferred aryl groups that may be mentioned herein are “phenyl”.
Unless otherwise specified, the term "heteroaryl” when used herein refers to an aromatic group containing one or more heteroatom(s) (e.g. one to four heteroatoms) preferably selected from N, O and S. Heteroaryl groups include those which have between 5 and 20 members (e.g. between 5 and 10) and may be monocyclic, bicyclic or tricyclic, provided that at least one of the rings is aromatic (so forming, for example, a mono-, bi-, or tricyclic heteroaromatic group). When the heteroaryl group is polycyclic the point of attachment may be via any atom including an atom of a non-aromatic ring. However, when heteroaryl groups are polycyclic (e.g. bicyclic or tricyclic), they are preferably linked to the rest of the molecule via an aromatic ring. Heteroaryl groups that may be mentioned include 3,4-dihydro- l//-isoquinolinyl, 1 ,3-dihydroisoindolyl,
1.3-dihydroisoindolyl (e.g. 3,4-dihydro- l/i-isoquinolin-2-yl, l,3-dihydroisoindol-2-yl,
1.3-dihydroisoindol-2-yl; i.e. heteroaryl groups that are linked via a non-aromatic ring), or, preferably, acridinyl, benzimidazolyl, benzodioxanyl, benzodioxepinyl, benzo- dioxolyl (including 1,3-benzodioxolyl), benzofuranyl, benzofurazanyl, benzothiadiazolyl (including 2,1,3-benzothiadiazolyl), benzothiazolyl, benzoxadiazolyl (including 2,1,3-benzoxadiazolyl), benzoxazinyl (including 3,4-dihydro-2//-l,4- benzoxazinyl), benzoxazolyl, benzomorpholinyl, benzoselenadiazolyl (including
2.1.3-benzoselenadiazolyl), benzothienyl, carbazolyl, chromanyl, cinnolinyl, furanyl, imidazolyl, imidazo[l,2-a]pyridyl, indazolyl, indolinyl, indolyl, isobenzofuranyl, isochromanyl, isoindolinyl, isoindolyl, isoquinolinyl, isothiaziolyl, isothiochromanyl, isoxazolyl, naphthyridinyl (including 1 ,6-naphthyridinyl or, preferably,
1 ,5-naphthyridinyl and 1,8-naphthyridinyl), oxadiazolyl (including 1,2,3-oxadiazolyl,
1.2.4-oxadiazolyl and 1,3,4-oxadiazolyl), oxazolyl, phenazinyl, phenothiazinyl, phthalazinyl, pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridyl, pyrimidinyl, pyrrolyl, quinazolinyl, quinolinyl, quinolizinyl, quinoxalinyl, tetrahydroisoquinolinyl (including 1,2,3,4-tetrahydroisoquinolinyl and 5,6,7,8-tetra- hydroisoquinolinyl), tetrahydroquinolinyl (including 1,2,3,4-tetrahydroquinolinyl and 5,6,7,8-tetrahydroquinolinyl), tetrazolyl, thiadiazolyl (including 1 ,2,3-thiadiazolyl,
1.2.4-thiadiazolyl and 1,3,4-thiadiazolyl), thiazolyl, thiochromanyl, thiophenetyl, thienyl, triazolyl (including 1,2,3-triazolyl, 1,2,4-triazolyl and 1,3,4-triazolyl) and the like. Substituents on heteroaryl groups may, where appropriate, be located on any atom in the ring system including a heteroatom. The point of attachment of heteroaryl groups may be via any atom in the ring system including (where appropriate) a heteroatom (such as a nitrogen atom), or an atom on any fused carboeyclic ring that may be present as part of the ring system. Heteroaryl groups may also be in the N- or S- oxidised form. Heteroaryl groups mentioned herein may be stated to be specifically monocyclic or bicyclic. When heteroaryl groups are polycyclic in which there is a nonaromatic ring present, then that non-aromatic ring may be substituted by one or more =0 group. Most preferred heteroaryl groups that may be mentioned herein are 5- or 6- membered aromatic groups containing 1, 2 or 3 heteroatoms (e.g, preferably selected from nitrogen, oxygen and sulfur).
It may be specifically stated that the heteroaryl group is monocyclic or bicyclic. In the case where it is specified that the heteroaryl is bicyclic, then it may consist of a five-, six- or seven-membered monocyclic ring (e.g. a monocyclic heteroaryl ring) fused with another five-, six- or seven-membered ring (e.g. a monocyclic aryl or heteroaryl ring).
Heteroatoms that may be mentioned include phosphorus, silicon, boron and, preferably, oxygen, nitrogen and sulfur.
When “aromatic” groups are referred to herein, they may be aryl or heteroaryl. When “aromatic linker groups” are referred to herein, they may be aryl or heteroaryl, as defined herein, are preferably monocyclic (but may be polycyclic) and attached to the remainder of the molecule via any possible atoms of that linker group. However, when, specifically carbocyclic aromatic linker groups are referred to, then such aromatic groups may not contain a heteroatom, i.e. they may be aryl (but not heteroaryl).
For the avoidance of doubt, where it is stated herein that a group may be substituted by one or more substituents (e.g, selected from C1-6 alkyl), then those substituents (e.g. alkyl groups) are independent of one another. That is, such groups may be substituted with the same substituent (e.g. same alkyl substituent) or different (e.g. alkyl) substituents.
All individual features (e.g. preferred features) mentioned herein may be taken in isolation or in combination with any other feature (including preferred feature) mentioned herein (hence, preferred features may be taken in conjunction with other preferred features, or independently of them).
The skilled person will appreciate that compounds of the invention that are the subject of this invention include those that are stable. That is, compounds of the invention include those that are sufficiently robust to survive isolation from e.g. a reaction mixture to a useful degree of purity. In an embodiment, R1 represents hydrogen or C1-3 alkyl. Preferred compounds of the invention include those in which R1 represents C1-3 alkyl such as methyl or ethyl. In another embodiment, R1 represents methyl. In an embodiment, Sub is not present. In a further embodiment, Sub represents one or two substituents selected from halo (e.g. fluoro) atom, -CN and C1-2 alkyl (e.g. methyl).
Compounds of the invention may have a non-aromatic A ring such as in formula la:
Figure imgf000017_0001
Alternatively, compounds of the invention may have an aromatic A ring such as in formula lb:
Figure imgf000017_0002
Compounds of the invention may have an aromatic 5-membered ring in which Xx represents a heteroatom such as nitrogen, oxygen or sulfur, such as in formula Ic.
Figure imgf000017_0003
In an embodiment the “A” ring is unsubstituted or substituted with one fluoro atom.
In an embodiment, the “A” ring is a 6-membered aromatic or non-aromatic ring. Preferred compounds of the invention include those in which the “B” ring contain at least one nitrogen atom (in an embodiment, at the ring junction); and/or contains one, two, three or four heteroatoms in total.
In an embodiment of the invention, compounds of the invention are those in which the “B” ring and adjacent 6 membered non-aromatic ring are represented by a sub-formula
(II) as defined hereinbelow (where it will be appreciated that the rules of valency will be adhered to, e.g. where C is mentioned then it may need to have a H attached to it), in which: one of X1 and X2 represents N (i.e. there is an essential nitrogen at the ring junction) and the other represents C; the other integers X3, X4 and X3 may represent C (or CH) or a heteroatom (such as N,
O and/or S; and, in an embodiment, represent N); and/or none, any one or two of X3, X4 and X5 represents a heteroatom (e.g. N, O and/or S; and, in an embodiment, N) and the other(s) represents C (or CH).
Hence, in view of the foregoing, preferred compounds of the invention include those in which: one of X1 and X2 represents N; and none, one or two of X3, X4 and X5 represents N.
In an embodiment, the “B” ring and adjacent 6 membered non-aromatic ring in compounds of the invention may be depicted as follows in sub formula (II) (in which the left hand side would be further bound to the requisite quinolinone, or tetrahydro- quinolinone, of formula (I) and the right hand side would be further bound to the L1 group of formula (I)):
Figure imgf000019_0001
wherein: one of X1 and X2 represents N (i.e. there is an essential nitrogen at the ring junction) and the other represents C; the other integers X3, X4 and X5 may represent C (or CH) or a heteroatom (such as N, O and/or S); and/or none, any one or two of X3, X4 and X"1 represents a heteroatom (e.g, N, O and/or S) and the other represents C (or CH), and in which in all of the cases above, it will be understood that the rules of valency will need to be adhered to.
In a particular embodiment, the “B” ring and adjacent 6 membered non-aromatic ring in compounds of the invention may be depicted as follows in sub formula (II) (in which the left hand side would be further bound to the requisite quinolinone, or tetrahydro- quinolinone, of formula (I) and the right hand side would be further bound to the L1 group of formula (I)):
Figure imgf000020_0001
wherein: one of X1 and X2 represents N (i.e. there is an essential nitrogen at the ring junction) and the other represents C; the other integers X3, X4 and X3 may represent C (or CH) or a heteroatom (such as N,
O and/or S); and/or none, any one or two of X3, X4 and X3 represents a heteroatom (e.g. N, O and/or S) and the other represents C (or CH), and in which in all of the cases above, it will be understood that the rules of valency will need to be adhered to. In a further embodiment, preferred compounds of the invention include those in which in the sub-formula (II) depicted above:
X1, X3 and X5 represent a heteroatom (e.g. nitrogen) and X2 and X4 represent C (or CH). In an alternate further embodiment, preferred compounds of the invention include those in which in the sub-formula (II) depicted above:
X2, X3 and X3 represent a heteroatom (e.g. nitrogen) and X1 and X4 represent C (or CH).
In an embodiment, the sub-formula (II) represents:
Figure imgf000020_0002
In an embodiment, the sub-formula (II) represents:
Figure imgf000021_0001
In a preferred embodiment the “B” ring and adjacent 6 membered non-aromatic ring in compounds of the invention may be depicted as follows, (in which the left hand side would be further bound to the requisite quinolinone, or tetrahydro-quinolinone, of formula (I) and the right hand side would be further bound to the L1 group of formula
(I)):
Figure imgf000021_0002
In yet a further embodiment, preferred compounds of the invention include those in which in the sub-formula (II) depicted above:
X2 and X3 represent a heteroatom (e.g. nitrogen) and X1, X4 and X5 represent C (or CH).
Other preferred compounds of the invention include those in which:
L1 represents a direct bond or -C(Rxl)(Rx2)-;
Rxl and Rx2 independently represent hydrogen for example: L1 may specifically represent a direct bond or -CHb- (or, in a more specific embodiment, a direct bond).
In a particular embodiment, L1 represents a direct bond. In an alternative embodiment, L1 represents -Ctb- (but is preferably a direct bond).
Figure imgf000022_0001
and hence there are three embodiments of the invention, and in an aspect, Z1 represents (i), (ii) or (iii) (e.g. Z1 represents (i) or (ii)). Hence, in an embodiment, Z1 represents an aromatic ring (i.e. (i), (ii) or (iii) above), for instance (i) or (ii).
In a further embodiment, compounds of the invention include those in which when ring C is present, it represents a 5-membered aromatic ring, it contains one, two or three heteroatoms preferably selected from nitrogen, oxygen and sulfur; in a further embodiment, such ring is optionally substituted by one or two substituents independently selected from Rf; when ring D is present, it represents a 6-membered aromatic ring containing one nitrogen atom; and, in a further embodiment, such ring is optionally substituted by one or two substituents independently selected from Rg;
Ra, Rb, Rc, Rd and Re independently represent hydrogen or a substituent selected from B1;
Rf and Rg each independently represent a substituent selected from B1. In an embodiment, when Ring C is present (i.e. Z1 represents (ii)), then such aromatic 5-membered (optionally substituted) ring may: (i) contain one sulfur atom (so forming a thienyl); (ii) contain one nitrogen and one sulfur atom (so forming e.g. thiazolyl); (iii) contain two nitrogen atoms (so forming e.g. a pyrazolyl); (iv) contains two nitrogen atoms and one sulfur atom; (v) contains two nitrogen atoms and one oxygen atom; (vi) contains three nitrogen atoms.
In an embodiment, when Ring D is present (i.e. Z1 represents (iii)), then such aromatic 6-membered ring may contain one nitrogen atom, so forming a pyridyl group (e.g. a 3- pyridyl group, or, in an alternative embodiment, a 2-pyridyl group or a 4-pyridyl group).
In an embodiment, further preferred compounds of the inventions include those in which: none, but preferably, one or two (e.g. one) of Ra, Rb, Rc, Rd and Re represents B1 and the others represent hydrogen; and/or one or two (e.g. one) of Rb . Rc and Rd (preferably Rc) represents B1 and the others represent hydrogen. In a further embodiment, preferred compounds of the inventions include those in which: Rb and one of Rc or Rd represent B1 and the others represent hydrogen.
In a further embodiment, preferred compounds of the inventions include those in which: Rb and Rc represent B1 and the others represent hydrogen.
In a further embodiment, preferred compounds of the inventions include those in which: Rb and Rd represent B1 and the others represent hydrogen.
In a further embodiment, preferred compounds of the inventions include those in which: Rb represent B' and the others represent hydrogen.
In a further embodiment, preferred compounds of the inventions include those in which: Rc represent B1 and the others represent hydrogen. In an embodiment of the invention:
Re2 and Re 4 independently represent hydrogen;
Rel, Re3 and Re5 each independently represent C1-3 alkyl (e.g. methyl) substituted by one or more fluoro atoms.
In a further embodiment, yet further preferred compounds of the inventions include those in which:
B 1 represents a substituent selected from:
(i) halo (e.g. fluoro or chloro) and, in an embodiment, fluoro; (ii) C1-6 alkyl, preferably C1-3 alkyl, substituted by one or more fluoro atom;
(iii) -ORel.
In a further embodiment of the invention, B1 represents a substituent selected from halo (e.g. fluoro or chloro), C1-3 alkyl (optionally substituted by one or more fluoro atom) and -ORel (in which Rel represents C1-3 alkyl optionally substituted by one or more fluoro atom, so forming e.g. -OCH3 or-OCF3). In a specific embodiment, B1 is selected from fluoro, -CH3, -OCH3, -CF3, -CHF2, -CH2CF3, -CH2CHF2, -CH2CH2CF3 and -OCF3. In an alternative embodiment, B1 may represent isopropyl or -S(0)2CF3. In a further specific embodiment, B1 is selected from fluoro, -CH3, -CF3, -OCH3 and
-OCF3.
In embodiments of the invention, Z1 represents:
(i)
(ii)
Figure imgf000024_0001
ring C represents a 5-membered aromatic ring containing at least two heteroatom, wherein at least one of said hetero atom is a nitrogen atom, and which ring is substituted by one or more substituents independently selected from Rf; one or two (e.g. one) of Rb Rc and Rd (preferably Rc) represents B1 and the others represent hydrogen;
Rf and Rh independently represent hydrogen or a substituent selected from B1; each B1 independently represents a substituent selected from:
(i) fluoro;
(ii) -ORel; (iii) -Rdl;
Rdl represents C1-6 alkyl, preferably C1-3 alkyl, optionally substituted by one or more fluoro atoms; and/or
Rel represent hydrogen or C 1-6 alkyl optionally substituted by one or more fluoro atoms.
PHARMACOLOGY
The compounds according to the invention have surprisingly been shown to be suitable for the treatment of a bacterial infection including a mycobacterial infection, particularly those diseases caused by pathogenic mycobacteria such as Mycobacterium tuberculosis (including the latent and drug resistant form thereof). The present invention thus also relates to compounds of the invention as defined hereinabove, for use as a medicine, in particular for use as a medicine for the treatment of a bacterial infection including a mycobacterial infection. Such compounds of the invention may act by interfering with ATP synthase in M. tuberculosis, with the inhibition of cytochrome bd activity being the primary mode of action. Such bd inhibition may have an effect in killing mycobacteria (and hence having an anti-tuberculosis effect directly). However, as cytochrome bd is not necessarily essential for aerobic growth, it may have the most pronounced effect in combination with another inhibitor of a target of the electron transport chain of mycobacteria. Such compounds may be tested for cytochrome bd activity by testing in an enzymatic assay, and may also be tested for activity in the treatment of a bacterial infection (e.g. mycobacterial infection) by testing the kill kinetics, for example of such compounds alone or in combination (as mentioned herein, e.g. with one or more other inhibitor(s) of a (different) target of the electron transport chain of mycobacteria; such other different targets may be more implicated in aerobic growth). Cytochrome bd is a component of the electron transport chain, and therefore may he implicated with ATP synthesis, for instance alone or especially with one or more other inhibitor(s) of a target of the electron transport chain of mycobacteria.
Further, the present invention also relates to the use of a compound of the invention, as well as any of the pharmaceutical compositions thereof as described hereinafter for the manufacture of a medicament for the treatment of a bacterial infection including a mycobacterial infection (for instance when such compound of the invention is used in combination with another inhibitor of a target of the electron transport chain of mycobacteria).
Accordingly, in another aspect, the invention provides a method of treating a patient suffering from, or at risk of, a bacterial infection, including a mycobacterial infection, which comprises administering to the patient a therapeutically effective amount of a compound or pharmaceutical composition according to the invention (for instance a therapeutically effective amount of a compound or pharmaceutical composition of the invention, in combination with one or more other inhibitor(s) of a target of the electron transport chain of mycobacteria).
The compounds of the present invention also show activity against resistant bacterial strains (for instance alone or in combination with another inhibitor of a target of the electron transport chain of mycobacteria). Whenever used hereinbefore or hereinafter, that the compounds can treat a bacterial infection (alone or in combination) it is meant that the compounds can treat an infection with one or more bacterial strains.
The invention also relates to a composition comprising a pharmaceutically acceptable carrier and, as active ingredient, a therapeutically effective amount of a compound according to the invention. The compounds according to the invention may be formulated into various pharmaceutical forms for administration purposes. As appropriate compositions there may be cited all compositions usually employed for systemically administering drugs. To prepare the pharmaceutical compositions of this invention, an effective amount of the particular compound, optionally in addition salt form, as the active ingredient is combined in intimate admixture with a pharmaceutically acceptable carrier, which carrier may take a wide variety of forms depending on the form of preparation desired for administration. These pharmaceutical compositions are desirable in unitary dosage form suitable, in particular, for administration orally or by parenteral injection. For example, in preparing the compositions in oral dosage form, any of the usual pharmaceutical media may be employed such as, for example, water, glycols, oils, alcohols and the like in the case of oral liquid preparations such as suspensions, syrups, elixirs, emulsions and solutions; or solid carriers such as starches, sugars, kaolin, diluents, lubricants, binders, disintegrating agents and the like in the case of powders, pills, capsules and tablets. Because of their ease in administration, tablets and capsules represent the most advantageous oral dosage unit forms in which case solid pharmaceutical carriers are obviously employed. For parenteral compositions, the carrier will usually comprise sterile water, at least in large part, though other ingredients, for example, to aid solubility, may be included. Injectable solutions, for example, may be prepared in which the carrier comprises saline solution, glucose solution or a mixture of saline and glucose solution. Injectable suspensions may also be prepared in which case appropriate liquid carriers, suspending agents and the like may be employed. Also included are solid form preparations which are intended to be converted, shortly before use, to liquid form preparations.
Depending on the mode of administration, the pharmaceutical composition will preferably comprise from 0.05 to 99 % by weight, more preferably from 0.1 to 70 % by weight, even more preferably from 0.1 to 50 % by weight of the active ingredient(s), and, from 1 to 99.95 % by weight, more preferably from 30 to 99.9 % by weight, even more preferably from 50 to 99.9 % by weight of a pharmaceutically acceptable carrier, all percentages being based on the total weight of the composition.
The pharmaceutical composition may additionally contain various other ingredients known in the art, for example, a lubricant, stabilising agent, buffering agent, emulsifying agent, viscosity-regulating agent, surfactant, preservative, flavouring or colorant.
It is especially advantageous to formulate the aforementioned pharmaceutical compositions in unit dosage form for ease of administration and uniformity of dosage. Unit dosage form as used herein refers to physically discrete units suitable as unitary dosages, each unit containing a predetermined quantity of active ingredient calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. Examples of such unit dosage forms are tablets (including scored or coated tablets), capsules, pills, powder packets, wafers, suppositories, injectable solutions or suspensions and the like, and segregated multiples thereof.
The daily dosage of the compound according to the invention will, of course, vary with the compound employed, the mode of administration, the treatment desired and the mycobacterial disease indicated. However, in general, satisfactory results will be obtained when the compound according to the invention is administered at a daily dosage not exceeding 1 gram, e.g. in the range from 10 to 50 mg/kg body weight.
Given the fact that the compounds of the invention are useful against bacterial infections, the present compounds may be combined with other antibacterial agents in order to effectively combat bacterial infections. Where it is indicated that compounds may be useful against bacterial infections, we mean that those compounds may have activity as such or those compounds may be effective in combination (as described herein, e.g. with one or more other inhibitors of the electron transport chain of mycobacteria) by enhancing activity or providing synergistic combinations, for example as may be described in the experimental hereinafter.
Therefore, the present invention also relates to a combination of (a) a compound according to the invention, and (b) one or more other antibacterial agents (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor). The present invention also relates to such a compound or combination, for use as a medicine. The present invention also relates to the use of a combination or pharmaceutical composition as defined directly above for the treatment of a bacterial infection.
A pharmaceutical composition comprising a pharmaceutically acceptable carrier and, as active ingredient, a therapeutically effective amount of (a) a compound according to the invention, and (b) one or more other antibacterial agents (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor), is also comprised by the present invention.
The weight ratio of (a) the compound according to the invention and (b) the other antibacterial agent(s) when given as a combination may be determined by the person skilled in the art. Said ratio and the exact dosage and frequency of administration depends on the particular compound according to the invention and the other antibacterial agent(s) used, the particular condition being treated, the severity of the condition being treated, the age, weight, gender, diet, time of administration and general physical condition of the particular patient, the mode of administration as well as other medication the individual may be taking, as is well known to those skilled in the art. Furthermore, it is evident that the effective daily amount may be lowered or increased depending on the response of the treated subject and/or depending on the evaluation of the physician prescribing the compounds of the instant invention. A particular weight ratio for the present compound of the invention and another antibacterial agent may range from 1/10 to 10/1, more in particular from 1/5 to 5/1, even more in particular from 1/3 to 3/1.
The compounds according to the invention and the one or more other antibacterial agents may be combined in a single preparation or they may be formulated in separate preparations so that they can be administered simultaneously, separately or sequentially. Thus, the present invention also relates to a product containing (a) a compound according to the invention, and (b) one or more other antibacterial agents (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor), as a combined preparation for simultaneous, separate or sequential use in the treatment of a bacterial infection. The other antibacterial agents which may be combined with the compounds of the invention are for example antibacterial agents known in the art. For example, the compounds of the invention may be combined with antibacterial agents known to interfere with the respiratory chain of Mycobacterium tuberculosis, including for example direct inhibitors of the ATP synthase (e.g. bedaquiline, bedaquiline fumarate or any other compounds that may have be disclosed in the prior art, e.g. compounds disclosed in W02004/011436), inhibitors of ndh2 (e.g. clofazimine) and inhibitors of cytochrome bd. Additional mycobacterial agents which may be combined with the compounds of the invention are for example rifampicin (=rifampin); isoniazid; pyrazinamide; amikacin; ethionamide; ethambutol; streptomycin; para-aminosalicylic acid; cycloserine; capreomycin; kanamycin; thioacetazone; PA-824; delamanid; quinolones/fluoroquinolones such as for example moxifloxaein, gatifloxacin, ofloxacin, ciprofloxacin, sparfloxacin; macrolides such as for example clarithromycin, amoxycillin with clavulanic acid; rifamycins; rifabutin; rifapentin; as well as others, which are currently being developed (but may not yet be on the market; see e.g. http://www.newtbdrugs.org/pipeline.php). In particular, and as mentioned herein, compounds of the invention may be combined with one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor. Given that the compounds of the invention might act as cytochrome bd inhibitors, and hence target the electron transport chain of the mycobacteria (thereby blocking energy production of mycobacteria), the compounds of the invention (cytochrome bd inhibitors), combinations with one or more other inhibitors of the electron transport chain is thought to be a potentially effective way of providing an efficient regimen against mycobacteria. Even if the compounds of the invention (cytochrome bd inhibitors) alone might not be effective against mycobacteria, combining with one or more other such inhibitors may provide an effective regimen where the activity of one or more components of the combination is/are enhanced and/or such combinations act more effectively (e.g. synergistically).
GENERAL PREPARATION
The compounds according to the invention can generally be prepared by a succession of steps, each of which may be known to the skilled person or described herein.
EXPERIMENTAL PART
Compounds of formula I may be prepared in accordance with the techniques employed in the examples hereinafter (and those methods know by those skilled in the art), for example by using the following techniques.
Compounds of formula (I) may be prepared by: (i) hydrogenation of a compound of formula (V),
Figure imgf000031_0001
in which the integers are hereinbefore defined, by reaction with an appropriate reagent such as Hi and a palladium on carbon catalyst (for example, as described in the examples).
It is evident that in the foregoing and in the following reactions, the reaction products may be isolated from the reaction medium and, if necessary, further purified according to methodologies generally known in the art, such as extraction, crystallization and chromatography. It is further evident that reaction products that exist in more than one enantiomeric form, may be isolated from their mixture by known techniques, in particular preparative chromatography, such as preparative HPLC, chiral chromatography. Individual diastereoisomers or individual enantiomers can also be obtained by Supercritical Fluid Chromatography (SCF). The starting materials and the intermediates are compounds that are either commercially available or may be prepared according to conventional reaction procedures generally known in the art.
Experimental
Compounds of formula I may be prepared in accordance with the techniques employed in the examples hereinafter (and those methods know by those skilled in the art), for example by using the following techniques.
It is evident that in the foregoing and in the following reactions, the reaction products may be isolated from the reaction medium and, if necessary, further purified according to methodologies generally known in the art, such as extraction, crystallization and chromatography. It is further evident that reaction products that exist in more than one enantiomeric form, may be isolated from their mixture by known techniques, in particular preparative chromatography, such as preparative HPLC, chiral chromatography. Individual diastereoisomers or individual enantiomers can also be obtained by Supercritical Fluid Chromatography (SCF).
The starting materials and the intermediates are compounds that are either commercially available or may be prepared according to conventional reaction procedures generally known in the art.
1. General Information Melting points
Melting points were recorded using a differential scanning calorimeter DSC 1 Mettler Toledo. Melting points were measured with a temperature gradient of 10°C per min from 25 to 350 °C. Values are peak values. Unless indicated, this method is used. An alternative method is with open capilliary tubes on a Mettler Toledo MP50, which may be indicated at “MT”. With this method, melting points are measured with a temperature gradient of 10 °C/minute. Maximum temperature is 300 °C. The melting point data is read from a digital display and checked from a video recording system. lH NMR
'H NMR spectra were recorded on a Bruker Avance DRX 400 spectrometer or Bruker Advance III 400 spectrometer using internal deuterium lock and equipped with reverse double-resonance (*H, 13C, SEI) probe head with z gradients and operating at 400 MHz for proton and 100 MHz for carbon and a Bruker Avance 500 MHz spectrometer equipped with a Bruker 5mm BBFO probe head with z gradients and operating at 500 MHz for proton and 125 MHz for carbon.
NMR spectra were recorded at ambient temperature unless otherwise stated.
Data are reported as follow: chemical shift in parts per million (ppm) relative to TMS (5 = 0 ppm) on the scale, integration, multiplicity (s = singulet, d = doublet, t = triplet, q = quartet, quin = quintuplet, sex = sextuplet, m = multiplet, b = broad, or a combination of these), coupling constant(s) J in Hertz (Hz).
HPLC- LCMS
Analytical methods LCMS
The mass of some compounds was recorded with LCMS (liquid chromatography mass spectrometry). The methods used are described below.
General procedure LCMS Methods The High Performance Liquid Chromatography (HPLC) measurement was performed using a LC pump, a diode-array (DAD) or a UV detector and a column as specified in the respective methods. If necessary, additional detectors were included (see table of methods below). Flow from the column was brought to the Mass Spectrometer (MS) which was configured with an atmospheric pressure ion source. It is within the knowledge of the skilled person to set the tune parameters (e.g. scanning range, dwell time...) in order to obtain ions allowing the identification of the compound’s nominal monoisotopic molecular weight (MW). Data acquisition was performed with appropriate software.
Compounds are described by their experimental retention times (Rt) and ions. If not specified differently in the table of data, the reported molecular ion corresponds to the [M+H]+ (protonated molecule) and/or [M-Hj (deprotonated molecule). In case the compound was not directly ionizable the type of adduct is specified (i.e. |M+N'H.i]\ [M+HCOOT, etc...). For molecules with multiple isotopic patterns (Br, Cl..), the reported value is the one obtained for the lowest isotope mass. All results were obtained with experimental uncertainties that are commonly associated with the method used. Hereinafter, “8QD” means Single Quadrupole Detector, “RT” room temperature, “BEH” bridged ethylsiloxane/silica hybrid, “HSS” High Strength Silica, “DAD” Diode Array Detector, “MSD” Mass Selective Detector. Table: LCMS Method codes (Flow expressed in mL/min; column temperature (T) in °C; Run time in minutes).
Figure imgf000033_0001
Figure imgf000034_0001
When a compound is a mixture of isomers which give different peaks in the LCMS method, only the retention time of the main component is given in the LCMS table.
2. Abbreviations (and formulae)
AcOH Acetic acid
AcCl Acetyl chloride
BrettPhos 2-(Dicyclohexylphosphino)3,6-dimethoxy-2',4',6'-triisopropyl- 1,1 '-biphenyl
BrettPhos Pd G3 [(2-Di-cyclohexylphosphino-3,6-dimethoxy-2',4',6'- triisopropyl- 1 , 1 '-biphenyl)-2-(2'-amino- 1,1' - biphenyl)]palladium(II) methanesulfonate methanesulfonate
CBr4 T etrabromomethane
CbzCl Benzyl chloroformate CH3CN Acetonitrile cs2co3 Cesium carbonate
CSA Camphor- 10-sulfonic acid
DCE Dichloroethane
DCM or CH2CI2 Dichloromethane
DIPEA N ,N -Diisopropylethylamine
DMAP 4-(Dimethylamino)pyridine
DME 1 ,2-Dimethoxyethane
DMF Dimethylformamide
DMF-DMA Az/V-dimethylformamide dimethyl acetal
DMSO Methyl sulfoxide
EDCI-HC1 N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride
Et20 Diethylether
Et3N or TEA Triethylamine EtOAc Ethyl acetate EtOH Ethanol h hour
Hi Dihydrogen gas
HATU Hexafluorophosphate Azabenzotriazole Tetramethyl Uronium
HC1 Hydrochloric acid
HFIP Hexafluoroisopropanol
HOBT·H2O 1-Hydroxybenzotriazole hydrate
/-PrOH Isopropyl alcohol
K2C03 Potassium carbonate
LiOH Lithium hydroxide
MeOH Methanol
MeTHF Methyltetrahydrofurane
MgSO. Magnesium sulfate min Minute
N2 Nitrogen
NaHC03 Sodium Bicarbonate
NaOH Sodium hydroxide NBS 1 -bromopyrrolidine-2,5-dione
NH4CI Ammonium, chloride
NH4HCO3 Ammonium bicarbonate
NMR Nuclear Magnetic Resonance
Pd/C Palladium on carbon
PdCl2(PPh3)2 Dichlorobis(triphenylphosphine)palladium(II)
Pd(OAc)2 Palladium(II) acetate
PIDA (Diacetoxyiodo)benzene
POCI3 Phosphorous Oxychloride
Ra-Ni Raney®-Nickel rt Room temperature
RuPhos 2-Dicyclohexylphosphino-2',6'-diisopropoxybiphenyl RuPhos Pd G3 (2-Dicyclohexylphosphino-2',6'-diisopropoxy- 1,1'- biphenyl)[2-(2'-amino-l, 1 '-biphenyl)] palladium(II) methanesulfonate t-AmylOH tert- Amyl alcohol
TBTU 0-(benzotriazole- 1 -yl)-N,N,N’ ,N’ -tetramethyluronium tetrafluoroborate
Tf20 Trifluoromethanesulfonic Anhydride
TFA Trifluoroactetic acid
THF Tetrahydrofuran
TMSC1 Trimethylsilyl chloride
TsOI I or PTSA p-Toluensulfonic acid
XantPhos 4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene
PdCl2(dppf)2 [1,1 ’-Bis(diphenylphosphino)ferrocene]dichloropalladium(II)
K3RO4·H2O Potassium phosphate monohydrate
KOtBu Potassium tert-butoxide Experimental Part
PREPARATION OF THE INTERMEDIATES
PREPARATION OF INTERMEDIATE 1
Figure imgf000037_0001
A stirred mixture of ethyl 6-bromoimidazo[l,2-a]pyrazine-2-carboxylate (CAS [1208085-94-2], 4.6 g, 17.07 mmol), 4-(trifluoromethoxy)phenylboronic acid (CAS [139301-27-2], 7.03 g, 34.14 mmol) and K3PO4 (10.87 g, 51.21 mmol) in 1,4-dioxane (30 mL) and H2O (21 mL) was bubbled with nitrogen. Then, PdCbidppfb (1.4 g, 1.71 mmol) was added and the mixture was stirred at 90 °C for 16 h. Water was added and the mixture was extracted with EtOAc (x3). The organic layer was dried over MgS04, filtered and concentrated in vacuo. The crude product was purified by flash column chromatography (dry load in celite; silica; EtOAc in Heptane, from 0/100 to 50/50). The desired fractions were collected and concentrated in vacuo to yield intermediate 1 (2.5 g, 38%) as a solid.
The following compounds were synthesized by the method already reported.
Figure imgf000037_0002
Figure imgf000038_0001
Figure imgf000039_0002
PREPARATION OF INTERMEDIATE 2
Figure imgf000039_0001
LiOH.PbO (CAS [1310-65-2], 322 mg, 7.52 mmol) in THF (20.5 mL) was added to intermediate 1 (2.4 g, 6.83 mmol), followed by ¾0 (6.8 mL) and the reaction mixture was stirred at rt for 16 h. Then, additional amount of LiOH. ¾0 (59 mg, 1.37 mmol) was added and the mixture was stirred at rt for 2 h. The solution was acidified with 1M HC1 until pH = 7 and it was concentrated in vacuo to yield intermediate 2 (2.43 g, 99%) as a solid. The crude product was used in the next step without further purification.
The following compounds were synthesized by the method already reported.
Figure imgf000040_0002
PREPARATION OF INTERMEDIATE 3
Figure imgf000040_0001
l-Chloro-N,N, 2-trimethyl- l-propenylamine (CAS [26189-59-3], 0.57 mL, 4.12 mmol) was added to a solution of intermediate 2 (1.21 g, 3.74 mmol) in 1,4-dioxane (22.5 mL) under nitrogen atmosphere. The reaction mixture was stirred at rt for 20 minutes. Then, additional amount of l-chloro-N,N, 2-trimethyl- l-propenylamine (0.21 mL, 1.5 mmol) was added and the mixture was stirred at rt for 30 minutes. Then, additional quantity of l-chloro-N,N, 2-trimethyl- 1-propenylamine (0.26 mL, 1.87 mmol) was added and the mixture was stirred for 15 minutes. Then, a solution of l-(2-aminophenyl)propan-l-one (CAS [1196-28-7], 0.61 g, 4.08 mmol) in 1,4-dioxane (11 mL) was added and the mixture was stirred at rt for 10 minutes. Then, DIPEA (0.97 mL, 5.56 mmol) was 5 added until pH basic (pH=8) and the mixture was stirred at rt for 16 h. Additional amount of l-(2-aminophenyl)propan-l-one (0.5 g, 3.33 mmol) in 1,4-dioxane (9 mL) was added to the mixture and it was stirred at rt for 2 h. Then, water was added and the precipitate was filtered and washed with water to yield intermediate 3 (1.18 g, 56%) as a brownish solid. The crude product was used in the next step without further 10 purification.
The following compounds were synthesized by the method already reported.
Figure imgf000041_0002
15 PREPARATION OF INTERMEDIATE 4
Figure imgf000041_0001
In a glass pressure bottle, NaOH (263 mg, 6.58 mmol) was added to a mixture of intermediate 3 (1.15 g, 2.02 mmol) in 1,4-dioxane (20 mL) under nitrogen atmosphere at rt. Then, the mixture was stirred at 110 °C for lh and 30 minutes. Heptane was added and the precipitate was filtered off yielding intermediate 4 ( 1 g, 96%) as an orangish solid.
The following compounds were synthesized by the method already reported.
5
Figure imgf000042_0002
PREPARATION OF INTERMEDIATE 5
Figure imgf000042_0001
1-5
10 K2CO3 (1.17 g, 8.48 mmol) was added to diethyl 3,5-pyrazoledicarboxylate (CAS L37687-24-4], 1.5 g, 7.07 mmol) and 2-bromo-4'-(trifluoromethoxy)acetophenone (CAS 103962-10-3], 2 g, 7.07 mmol) in acetone (7 mL) at rt. The mixture was stirred at rt for 16 h. Water was added and the mixture was extracted with DCM. The organic layer was separated, dried over MgS04, filtered and concentrated in vacuo to yield 15 intermediate 5 (2.61 g, 80%) as a yellow oil. PREPARATION OF INTERMEDIATE 6
Figure imgf000043_0001
Ammonium acetate (4.86 g, 62.99 mmol) was added to a solution of intermediate 5 (2.61 g, 6.3 mmol) in glacial acetic acid (80 mL) at it. The mixture was stirred at 120 °C for 2 days. Additional amount of ammonium acetate (2.43 g, 31 .5 mmol) was added and the mixture was stirred at 120 °C for 2 days. The solvent was removed in vacuo. The crude was neutralized with NaiC03 aq. sat. sol. The precipitate was filtered and washed with cold water to yield intermediate 6 (2.06 g, 80%) as a beige solid. PREPARATION OF INTERMEDIATE 7
Figure imgf000043_0002
Intermediate 6 (2.06 g, 5.61 mmol) in POCb (39.4 mL) was heated at 110° C for 2 h. The reaction mixture was poured into ice-water, then Nall CO * aq. sat. sol. (20 ml) was added, finally K2CO3 was added until pH 7. The precipitate was filtered, washed with water and dried in vacuo to yield intermediate 7 (0.75 g, 33%) as a brown solid.
PREPARATION OF INTERMEDIATE 8
Figure imgf000043_0003
LiOH.tbO (CAS [1310-65-2], 99 mg, 2.3 mmol) in THE (5 mL) was added to intermediate 7 (740 mg, 1.92 mmol), followed by ¾0 (1.5 mL) and the reaction mixture was stirred at rt for 3 h. The solution was acidified with 1M HC1 until pH = 7 and it was concentrated in vacuo to yield intermediate 8 (755 mg, 99%) as a yellow solid. The crude product was used in the next step without further purification.
The following compounds were synthesized by the method already reported.
Figure imgf000044_0002
PREPARATION OF INTERMEDIATE 9
Figure imgf000044_0001
1 -Chloro-N,N, 2-trimethyl- 1 -propenylamine (CAS [26189-59-3], 0.39 mL, 2.85 mmol) was added to a solution of intermediate 8 (679 mg, 1.9 mmol) in 1,4-dioxane (6 mL) under nitrogen atmosphere. The reaction mixture was stirred at rt for 20 minutes. Additional amount of l-chloro-N,N, 2-trimethyl- 1 -propenylamine (0.39 mL, 2.85 mmol) was added and the mixture was stirred at rt for 30 minutes. Then, a solution of l-(2-aminophenyl)propan-l-one (CAS [1196-28-7], 309 mg, 2.07 mmol) in 1,4- dioxane (3 mL) was added to the mixture. DIPEA (0.43 mL, 2.44 mmol) was added until pH basic (pH=8) and the mixture was stirred at rt for 16 h. Then, water was added and the precipitate was filtered to yield intermediate 9 (565 mg, 58%) as a yellow solid.
The following compounds were synthesized by the method already reported.
Figure imgf000045_0001
Figure imgf000046_0001
PREPARATION OF INTERMEDIATE 10
Figure imgf000047_0001
In a glass pressure bottle, KOtBu (198 mg, 1.73 mmol) was added to a mixture of intermediate 9 (565 mg, 1.16 mmol) in 1,4-dioxane (7 mL) under nitrogen atmosphere at rt. Then, the mixture was stirred at 110 °C for 2h. The crude was concentrated in vacuo to yield intermediate 10 (635 mg, 98%) as a yellow solid.
The following compounds were synthesized by the method already reported.
Figure imgf000047_0003
PREPARATION OF INTERMEDIATE 11
Figure imgf000047_0002
To an argon-purged mixture of 2-amino-5-bromopyrazine (CAS [59489-71-3 ], 12.0 g, 69.0 mmol), 4-(trifluoromethoxy)phenylboronic acid (CAS [139301-27-2 ], 17.0 g,
82.8 mmol), K3PO4.H2O (47.6 g, 207 mmol) in a mixture of 1,4-dioxane (320 mL) and H2O (72 mL) was added PdCh(dppf)2 (2.52 g, 3.45 mmol) under argon atmosphere at rt. The resulting mixture was stirred at 100 °C for 16 h. After cooling to rt the mixture was concentrated to dryness under reduced pressure. The residue was diluted with DCM (300 mL) and water (300 mL) and the layers were separated. The aqueous layer was extracted with DCM (3 x 300 mL) and the combined organic layers were washed with brine (300 mL). The emulsion formed was concentrated under reduced pressure to remove DCM. The residue was taken in water, filtered and washed with water (500 mL). The solid was dissolved in DCM (250 mL), dried over NaiSCL, filtered and concentrated to dryness under reduced pressure. The residue was purified by flash chromatography over silica gel (cartridge: Interchim IR50SI F0800, eluent: DCM/EtOAc from 100/0 to 70/30 over 40 min) to afford intermediate 11 (15.8 g, 90%) as a black solid.
The following compounds were synthesized by the method already reported.
Figure imgf000048_0002
PREPARATION OF INTERMEDIATE 12
Figure imgf000048_0001
Intermediate 11 (15.8 g, 61.9 mmol) was added to a solution of O- (mesitylsulfonyl)hydroxylamine (CAS [36016-40-7], 0.23 M in DCM, 323 mL, 74.3 mmol) under argon atmosphere at 0 °C. The reaction mixture was warmed to room temperature and stirred for 18 h. The precipitate was filtered, washed with DCM (300 mL) and vaccum-dried to afford intermediate 12 (28.1 g, 96%) as a beige solid. The following compounds were synthesized by the method already reported.
Figure imgf000049_0002
PREPARATION OF INTERMEDIATE 13
Figure imgf000049_0001
An argon-purged solution of intermediate 12 (28. 1 g, 59.7 mmol) and ethyl chlorooxoacetate (CAS [4755-77-5], 13.3 mL, 119 mmol) in pyridine (140 mL) was stirred at 100 °C for 17 h, then cooled to room temperature. The reaction mixture was concentrated under reduced pressure, quenched with aq. sat NaHC03 solution (150 ml, pH~9-10) and stirred for 1 h at room temperature. The precipitate formed was filtered on a glass-frit, washed with water (200 mL) and vaccum-dried (60 °C, 2 days). The residue was purified by flash chromatography over silica gel (cartridge: Interchim IR50SI F0800, eluent: cyelohexane/EtOAc from 100/0 to 0/100 over 60 min then DCM/EtOAC 80/20 over 15 min) to afford intermediate 13 (15.1 g, 72%) as a green solid.
The following compounds were synthesized by the method already reported.
Figure imgf000050_0002
PREPARATION OF INTERMEDIATE 14
Figure imgf000050_0001
To a solution of intermediate 13 (7.50 g, 21.3 mmol) in THF (90 mL) were added UOH.H2O (CAS [1310-65-2], 893 mg, 21.3 mmol) and H20 (90 mL) and the resulting mixture was stirred at room temperature for 2.5 h. The mixture was concentrated to dryness under reduced pressure and vacuum-dried (60 °C, overnight) to afford intermediate 14 (7.74 g, quant.) as a green solid which was used as such in the next step.
PREPARATION OF INTERMEDIATE 15
Figure imgf000051_0001
To an argon-purged solution of intermediate 14 (7.74 g, 21.3 mmol) in DCM (180 mL) were added DMF (three drops) and oxalyl chloride (CAS [79-37-8], 3.60 mL, 42.6 mmol) at 0 °C. The resulting mixture was stirred at 0 °C for 0.5 h, then warmed to room temperature and stirred for 4 h. The reaction mixture was concentrated to dryness under reduced pressure. The residue was taken in 1,4-dioxane (150 mL) and a solution of l-(2-aminophenyl)propan-l-one (CAS [1196-28-7], 3.81 g, 25.5 mmol) in 1 ,4- dioxane (60 ml) was added and the resulting mixture was stirred at rt for 22 h. The reaction mixture was filtered on a glass-frit and the solid was washed with water (400 mL) and vacuum-dried (60 °C, overnight). The residue was dissolved in a DCM/MeOH mixture (9: 1, 600 mL) and washed with a saturated aqueous solution of NaHCCb (2 x 200 mL). The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure to afford intermediate 15 (7.1 g, 73%) as a green solid. PREPARATION OF INTERMEDIATE 16
Figure imgf000052_0001
An argon-purged mixture of intermediate 15 (7.10 g, 15.6 mmol) and NaOH (1.87 g, 46.8 mmol) in 1,4-dioxane (155 mL) was stirred at 110 °C for 16 h then. After cooling to rt, the reaction mixture was concentrated to dryness under reduced pressure and the residue was acidified with a 1.0 M HC1 aq. solution (100 mL, pH~l). The resulting mixture was filtered on glass-frit, the solid was washed with water (400 mL) and dried under vacuum at 60 °C for 16 h to afford intermediate 16 (6.26 g, 92%) as a yellowish solid.
PREPARATION OF INTERMEDIATE 17
Figure imgf000052_0002
In a round bottom flask, dry DMF (19 mΐ, 0.25 mmol) was added to a solution of intermediate 14 (810 mg, 2.5 mmol) in 1,4-dioxane (15 mL) at rt under nitrogen atmosphere. Then, oxalyl chloride (CAS [79-37-8], 0.22 mL, 2.5 mmol) was added and the reaction mixture was stirred at rt for 15min. Then, additional amount of oxalyl chloride (0.22 mL, 2.5 mmol) was added and the reaction mixture was stirred at rt for 15 minutes. A solution of l-(2-amino-5-fluorophenyl)propan-l-one (CAS [124623-14- 9 ], 415 mg, 2.48 mmol) in 1,4-dioxane (3mL) was added to the mixture. Then, DIPEA (3.02 mL, 17.36 mmol) was added at rt until pH= 8 and the mixture was stirred at rt for
4 h. Additional amount of l-(2-amino-5-fluorophenyl)propan-l-one (415 mg, 2.48 mmol) in 1,4-dioxane (3mL) was added and the reaction mixture was stirred at rt for 15 min. Then, water was added and the precipitate was filtered and washed with water to yield intermediate 17 (2 g, 95%) as a brownish solid that was used in the next step without further purification. PREPARATION OF INTERMEDIATE 18
Figure imgf000053_0001
In a glass pressure bottle, NaOH (549 mg, 13.73 mmol) was added to intermediate 17 (2 g, 4.22 mmol) in 1,4-dioxane (40.5 mL) under nitrogen atmosphere at rt. Then, the mixture was stirred at 110 °C for 2 h. The mixture was cooled to rt and heptane was added. The precipitate was filtered and washed with heptane to yield intermediate 18 (1.9 g, 71%) as a redish solid that was used in the next step without further purification.
The following compounds were synthesized by the method already reported.
Figure imgf000053_0002
Figure imgf000054_0001
PREPARATION OF INTERMEDIATE 19
Figure imgf000055_0001
Copper(II) bromide (CAS [7789-45-9], 15.25 g, 68.28 mmol) was added to a mixture 2-oxo-butyric acid ethyl ester (CAS [15933-07-0], 2.96 g, 22.76 mmol) in dry CHCE (8 mL) and EtO Ac (5 mL) at rt. The mixture was stirred at 90 °C for 16 h. Then the mixture was cooled to rt, filtered through of pad of celite and risen with EtOAc/heptane (1:2). The filtrate was concentrated in vacuo to yield a dark yellow oil. Then, 2-amino- 5-bromopyrazine (CAS [59489-71-3], 1.98 g, 11.38 mmol) and 1,4-dioxane (28 mL) were added and the mixture was stirred at 90 °C for 48 h. The solvent was removed in vacuo to yield intermediate 19 (5.77 g, 89%) which was used in the next step without further purification.
PREPARATION OF INTERMEDIATE 20
Figure imgf000055_0002
10% Pd/C (600 mg, 0.49 mmol) was added to a solution of 4-chloro-iV-(2- propionylphenyl)-6-(4-(trifluoromethyl)phenyl)pyrazolo[l,5-n]pyrazine-2-carboxamide (synthetized according to the procedure reported for intermediate 9) (1.17 g, 2.47 mmol) in EtOH (10 mL) and EtO Ac (10 mL) under nitrogen atmosphere at 0 °C. The mixture was stirred under Lb atmospheric pressure at rt for 24 h. The reaction was filtered through a pad of celite® and solvents were evaporated in vacuo to yield intermediate 20 (848 mg, 54%) as a yellow solid. PREPARATION OF INTERMEDIATE 21
Figure imgf000056_0001
Pyridinium chlorochromate (CAS [26299-14-9], 482 mg, 2.24 mmol) was added to a solution of intermediate 20 (665 mg, 1.5 mmol) in dry DCM (8 mL) at rt. The mixture was stirred at rt for 2 h. The reaction was filtered through a pad of celite® and solvents were evaporated in vacuo. The crude was purified by flash column chromatography (silica; EtOAc in heptane from 0/100 to 60/40 and DCM/MeOH (9: 1) in DCM from 0/100 to 100/0). The desired fractions were collected and concentrated in vacuo to yield intermediate 21 (442 mg, 51%) as a brown solid.
PREPARATION OF INTERMEDIATE 22
Figure imgf000056_0002
In a sealed tube, Hexamethylditin [661-69-8] (0.9 mL, 4.34 mmol) was added to 2- Bromo-5-(trifluoromethoxy)pyridine [888327-36-4] (1.38 g, 5.42 mmol), and Tetrakis(triphenylphosphine)palladium(0) [14221-01-3] (0.63 g, 0.54 mmol), in Dry Toluene (27 mL) after bubbling the mixture with nitrogen for 10 minutes. The reaction mixture was heated at 100 °C for 16 h. LCMS showed complete conversion into the desired product and no starting material. Yielding intermediate 22. The reaction mixture was used in the next step without any work-up or further purification. PREPARATION OF INTERMEDIATE 23
Figure imgf000057_0001
In a sealed tube, to the intermediate 22 (1.77 g; 5.42 mmol) in dry toluene (27 ml) were added intermediate intermediate 25 (1.22 g; 4.52 mmol) and Tetrakis(triphenylphosphine)palladium(0) [14221-01-3] (1.57 g; 1.36 mmol) under nitrogen atmosphere. The reaction mixture was desgassed with nitrogen and heated at 100 °C for 72 h. The mixture was filtered through of pad of celite, washed with absolute ethanol and concentrated under vacuum. The crude was purified by flash column chromatography twice (First purificationrdry loading, silica, 120 g; EtOAc in heptane from 0/100 to 50/50); (second purification: silica, 80 g; EtOAc in heptane from 0/100 to 30/70). The desired fractions were collected and concentrated in vacuo to yield intermediate 23 (489 mg, 28 %) as a light yellow solid.
PREPARATION OF INTERMEDIATE 26
Figure imgf000057_0002
In a sealed tube, Sodium 5-(trifluoromethyl)pyridine-2-sulfinate [cas 2098851-48-8J (3.8 g, 14.8 mmol), intermediate 25 (2 g, 7.4 mmol) and potassium carbonate [584-08-
7] (1.5 g, 11.1 mmol) were dissolved in dry dioxane [123-91-1] (126 mL) under a nitrogen. Tricyclohexylphosphine [2622-14-2] (517 mg, 1.85 mmol) and palladium(II) Acetate [3375-31-3] (828 mg, 3.7 mmol) were added and the reaction was stirred at 150 °C for 22 hour.
The mixture was allowed to cool down to rt, filtered over a pad of celite, and washed with EtOAc and water. The organic layer was washed with brine, separated, dried over MgS04 and the solvent evaporated in vacuo. The crude product was purified by flash column chromatography (80 g silica; heptane/EtOAc from 100/0 to 70/30). The desired fractions were collected, and the solvent evaporated in vacuo to yield intermediate 26 (890 mg, 36 %) as a yellow solid. PREPARATION OF INTERMEDIATE 30
Figure imgf000058_0001
20% Palladium hydroxide on carbon [12135-22-7] (544 mg, 0.77 mmol) was added to a solution of intermediate 29 (2.5 g, 7.75 mmol) in EtOH (33 mL) THF (33 mL) and AcOH (3 mL) under nitrogen atmosphere. The mixture was stirred under ¾ atmospheric pressure at 60 °C for 18 h. Then, the reaction was filtered through a pad of celite®, washed with DCM/MeOH (50v/50v) and the solvent was evaporated in vacuo. Toluene was added to the residue, and the solvent was evaporated off under reduced pressure to yield intermediate 30 as a colorless oil (2.7 g, 92%)
PREPARATION OF INTERMEDIATE 31
Figure imgf000058_0002
In a round bottom flask, Di-tert-butyl dicarbonate (CAS [24424-99-5], 6.6 mL, 28.7 mmol) was added to a stirred solution of intermediate 30 (2.79 g, 7.14 mmol), Triethylamine (CAS [121-44-8], 3.5 mL, 25 mmol), DMAP (CAS [1122-58-3], 175 mg, 1.43 mmol), in DCM (35 mL) at rt under N2 atmosphere. The mixture was stirred at rt for 64 hours. Then, the reaction mixture was diluted with water and extracted with DCM. The organic layer was separated, dried over MgS04 and filtered. The solvent was evaporated in vacuo. The crude product (5.4 g) was purified by flash column chromatography (80 g silica; MeOH/DCM from 0/100 to 10/90). The desired fractions were collected, and the solvent evaporated in vacuo to yield intermediate 31 ( 1.94 g, 59%) as a pale orange solid. PREPARATION OF INTERMEDIATE 32
Figure imgf000059_0001
In a round bottom flask, 2-Bromo-5-fluoro-4-methylpyridine [885168-20-7] (3.0 g, 15.8 mmol) was added to a solution of sodium 1 -methyl 3-sulfinopropanoate [90030- 48-1] (8.7 g, 47.37 mmol) and Cul [7681-65-4] (9.0 g, 47.37 mmol) in DMSO (150 mL). The reaction was stirred under a nitrogen atmosphere at 110 °C for 4 h. The mixture was then cooled to rt, diluted with ethyl acetate and washed with water. The organic phase was separated, dried over MgS04, filtered, and concentrated in vacuo. The residue was purified by flash column chromatography over silica gel (80 g, silica, EtOAc in DCM from 0/100 to 40/60) to yield intermediate 32 ( 1.16 g, 28 %) as a yellowish sticky solid.
PREPARATION OF INTERMEDIATE 33
Figure imgf000059_0002
In a screw top vial, intermediate 32 (1.155 g, 3.979 mmol), intermediate 25 (539 mg, 1.989 mmol) and potassium carbonate [584-08-7] (412 mg, 2.98 mmol, 1.5 equiv.) were added in dry dioxane (120 mL). The mixture was deoxygenated by bubbling nitrogen for 2 min. Then, Palladium (II) acetate [3375-31-3] (223.3 mg, 0.995 mmol, 0.5 equiv.) and tricyclohexylphosphine [2622-14-2] (140 mg, 0.497 mmol, 0.25 equiv.) were added, the tube was closed, and the reaction mixture was stirred at 150 °C for 16 h. Then, intermediate 25 (180 mg, 0.663 mmol) and potassium carbonate [584-08-7] (138 mg, 0.995 mmol, 0.5 equiv.) were added to the mixture of one batch. The mixture was deoxygenated by bubbling nitrogen for 2 min. Then, Palladium (II) acetate [3375- 31-3] (75 mg, 0.333 mmol, 0.17 equiv.) and tricyclohexylphosphine [2622-14-2] (46 mg, 0.165 mmol, 0.083 equiv.) were added, the tube was closed, and the reaction mixture was stirred at 150 °C for 16 h. The mixture was allowed to cool down to rt, filtered over a pad of celite, and washed with EtOAc. Then, water was added to the filtrate and the mixture was extracted with EtOAc. The organic phase was washed with brine, separated and dried over MgS04 and the solvent evaporated in vacuo. The crude product was purified by flash column chromatography (120 g silica; EtOAc in DCM from 100/0 to 10/90). The desired fractions were collected, and the solvent evaporated in vacuo to yield intermediate 33 (215 mg, 32 %) as a yellow solid.
PREPARATION OF INTERMEDIATE 34
Figure imgf000060_0001
In a screw top vial, intermediate 24 (610 mg, 1.56 mmol) was added to a mixture of 3- methyl-4-oxo-lH-quinoline-2-carboxylic acid [CAS: 402491-58-1] (212 mg, 1.04 mmol), EDC hydrochloride acid [CAS: 25952-53-8] (240 mg, 1.25 mmol), and Pyridine (11 mL, 136 mmol) at rt. The mixture was stirred at 90 °C for 16 h. LCMS analysis showed desired product.
HC1 (1M) aqueous solution was added to the mixture and was extracted with AcOEt. The organic layer was dried over MgS04, filtered and concentrated in vacuo.
The crude product was purified by flash column chromatography (silica, 40 g, AcOEt in Heptane from 0/100 to 100/0). The desired fractions were collected and concentrated in vacuo to yield, intermediate 34 as a brownish solid.
PREPARATION OF INTERMEDIATE 35
Figure imgf000060_0002
4-(Trifluoromethoxy)benzylzinc bromide, 0.5 M in tetrahydrofuran [1251848-83-5] (9 ml, 4.65 mmol) was added to a stirred solution, intermediate 25 (630 mg, 2.32 mmol) and Bis(tri-tert-butylphosphine)palladium(0) [53199-31-8] (119 mg, 0.23 mmol) in dry THF (10 ml) at 0°C while nitrogen was bubbling. The mixture was stirred at 50 °C for 16 h.
The reaction was quenched with NH4C1 (0.5 ml). The solvent was removed in vacuo. Then EtOH (10 ml) and H2S04 con. (0.1 ml) were added and the mixture was stirred at 95 °C for 16 h.
The reaction mixture was diluted with NaHC()3 and extracted with EtOAc. The combined organic layer was dried MgS04, filtered and the solvent evaporated in vacuo. The crude product was purified by flash column chromatography (25g. Si02; DCM/MeOH (9:1) in DCM from 0/100 to 100/0). The desired fractions were collected and concentrated in vacuo to yield intermediate 35 (860 mg, yield: 96 %) as a brownish solid.
PREPARATION OF THE FINAL COMPOUNDS El. PREPARATION OF FINAL COMPOUND 1
Figure imgf000061_0001
10% Pd/C (190 mg, 0. 16 mmol) was added to a solution of intermediate 4 (1.09 g, 2.5 mmol) in EtOH (20 mL) and EtOAc (20 mL) under nitrogen atmosphere at 0 °C. The mixture was stirred under ¾ atmospheric pressure at rt for 16 h. Then, the reaction mixture was stirred at 60 °C for 8 h and at 50 °C for 16 h. Then, additional amount of 10% Pd/C ( 190 mg, 0.16 mmol) was added and the mixture was stirred at 60 °C for 8 h and at 50 °C for 16 h. The reaction was filtered through a pad of celite®, washed with DCM/MeOH (50v/50v) and solvents were evaporated in vacuo. The crude was purified by flash column chromatography (dry load in silica; DCM/MeOH (20: 1) in DCM from 0/100 to 60/40). The desired factions were collected and concentrated in vacuo to yield a first fraction of compound 1 (119 mg, 11%, 98% pure) and a second fraction of compound 1 (380 mg, 31%, 90% pure) as beige solids. 1H NMR (400 MHz, DMSO) d 11.24 (s, 1H), 8.07 (dd, J = 8.1, 1.2 Hz, 1H), 7.94 (d, J = 8.3 Hz, 1H), 7.76 (s, 1H), 7.65 (d, J = 8.7 Hz, 2H), 7.58 - 7.54 (m, 1H), 7.42 (d, J = 8.0 Hz, 2H), 7.26 - 7.20 (m, 1H), 4.41 (dd, J = 12.0, 4.0 Hz, 1H), 4.35 - 4.27 (m, 1H), 4.25 -4.08 (m, 2H), 4.00 - 3.91 (m, 1H), 3.43 - 3.36 (m, 1H), 2.23 (s, 3H).
E2. PREPARATION OF FINAL COMPOUND 2
Figure imgf000062_0002
10% Pd/C (150 mg, 0.12 mmol) was added to a solution of intermediate 10 (540 mg, 1.15 mmol) in EtOH (15 mL) and EtOAc (15 mL) under nitrogen atmosphere at 0 °C.
The mixture was hydrogenated (atmospheric pressure) at 60 °C for 20 h. The reaction was filtered through a pad of celite® and the solvents were evaporated in vacuo. The crude was purified by flash column chromatography (dry load in silica; DCM/MeOH (9:1) in DCM from 0/100 to 50/50). The desired factions were collected and concentrated in vacuo to yield compound 2 (137 mg, 26%) as a white solid.
1H NMR (400 MHz, DMSO) d 11.40 (s, 1H), 8.09 (dd, J = 8.1, 1.2 Hz, 1H), 7.79 (d, J = 8.2 Hz, 1H), 7.68 (d, J = 8.7 Hz, 2H), 7.63 - 7.56 (m, 1H), 7.42 (d, J = 8.0 Hz, 2H), 7.30 - 7.23 (m, 1H), 6.59 (s, 1H), 4.51 (dd, J = 12.1, 4.0 Hz, 1H), 4.39 - 4.30 (m, 1H), 4.28 - 4.20 (m, 1H), 4.10 (dd, J = 16.3, 6.9 Hz, 1H), 4.07 - 3.98 (m, 1H), 2.17 (s, 3H), (-NH was not observed).
E3. PREPARATION OF FINAL COMPOUNDS 3, 4 and 5
Figure imgf000062_0001
An argon-purged solution of intermediate 16 (6.26 g, 14.3 mmol) in EtOH (130 mL) was hydrogenated (atmospheric pressure) in the presence of 10% Pd/C (3.05 g, 2.86 mmol) under stirring at 60 °C for 30 h, then cooled to room temperature. The reaction mixture was filtered through celite® and the filter-cake was rinsed with a DCM/MeOH mixture (9: 1, 400 mL). The filtrate was concentrated to dryness under reduced pressure. The residue was purified by flash chromatography over silica gel (cartridge: Interchim IR50SIF0220, eluent: DCM/MeOH from 100/0 to 95/5 over 40 min) affording compound 3 (4.04 g, 64%) as a white solid. Compound 3 (4 g) was purified via chiral SFC (Stationary phase: CHIRALPAK IA 5pm 250*30mm, Mobile phase: 60% C02, 40% mixture of EtOH/DCM 90/10 v/v (+0.3% iPrNIl·)). Pure fractions were collected and evaporated affording compound 4 (2.02 g) and compound 5 (1.88 g).
Compound 4 (0.3 g) was triturated with DIPE and heptane. The precipitate was filtered off and dried overnight under reduced pressure at 60°C affording pure compound 4
(0.268 g).
‘H NMR (500 MHz, DMSO-ife) d ppm 1 1 .66 (s, 1 H) 8.11 (dd, 7=8.24, 1.22 Hz, 1 H) 7.92 (d, 7=8.39 Hz, 1 H) 7.68 (d, 7=8.70 Hz, 2 H) 7.62 (ddd, 7=8.43, 6.98, 1.53 Hz, 1 H) 7.43 (d, 7=8.09 Hz, 2 H) 7.34 - 7.21 (m, 1 H) 4.63 (dd, 7=12.13, 4.04 Hz, 1 H) 4.51 - 4.40 (m, 1 H) 4.36 - 4.09 (m, 3 H) 3.50 (td, 7=7,82, 3.74 Hz, 1 H) 2.35 (s, 3 H).
Compound 5 (0.3 g) was triturated with DIPE and heptane. The precipitate was filtered off and dried overnight under reduced pressure at 60°C affording pure compound 5
(0.281 g).
*H NMR (500 MHz, DMSO -de) d ppm 11.66 (s, 1 H) 8.11 (dd, 7=8.24, 1.22 Hz, 1 H) 7.92 (d, 7=8.39 Hz, 1 H) 7.68 (d, 7=8.70 Hz, 2 H) 7.62 (ddd, 7=8.43, 6.98, 1 .53 Hz, 1
H) 7.43 (d, 7=8.09 Hz, 2 H) 7.34 - 7.21 (m, 1 H) 4.63 (dd, 7=12.13, 4.04 Hz, 1 H) 4.51 - 4.40 (m, 1 H) 4.36 - 4.09 (m, 3 H) 3.50 (td, 7=7.82, 3.74 Hz, 1 H) 2.35 (s, 3 H).
PREPARATION OF FINAL COMPOUND 7
Figure imgf000063_0001
HC14N in dioxane (15.4 mL, 62 mmol) was added to a solution of intermediate 53 (2.4 g, 3.09 mmol) in a mixture of DCM/Dioxane (160mL). The mixture was stirred at rt for 18 h. The mixture was concentrated in vacuo, then the crude was triturated with sat. aq. NaHC03 solution and washed with H20. The crude product was triturated with DCM and dried in vacuo, then dissolved in hot DCM/MeOH 9/ 1 and filtered off the impurities. The filtrated was concentrated in vacuo and the solid was dried to yield compound 7 (295 mg, yield 20.73%) as a pale yellow solid.
1H NMR (400 MHz, DMSO) d 11.85 (s, 1H), 8.02 (dd, J = 9.2, 4.7 Hz, 1H), 7.74 (dd, J = 9.4, 3.0 Hz, 1H), 7.56 (td, J = 8.7, 3.0 Hz, 1H), 7.37 (dd, J = 8.5, 1.7 Hz, 1H), 7.25
(dd, J = 11.5, 8.3 Hz, 1H), 7.08 (ddd, J = 8.3, 4.3, 2.0 Hz, 1H), 4.62 (dd, J = 12.1, 3.9 Hz, 1H), 4.45 - 4.14 (m, 5H), 3.87 (s, 3H), 2.36 (s, 3H).
E5. PREPARATION OF FINAL COMPOUND 18
Figure imgf000064_0001
In a glass pressure bottle, NaOH (109 mg, 2.73 mmol) was added to intermediate 21 (372 mg, 0.84 mmol) in dry 1,4-dioxane (8 mL) under nitrogen atmosphere at rt. The mixture was stirred at 110 °C for 2 h. The crude was concentrated in vacuo and purified by flash column chromatography (silica; DCM/MeOH (9: 1 ) in DCM from 0/100 to 60/40). The desired fractions were collected and concentrated in vacuo to yield compound 18 (148 mg, yield 40%) as a yellow solid.
1H NMR (400 MHz, DMSO) d 11.40 (s, 1H), 8.09 (dd, J = 8.1, 1.3 Hz, 1H), 7.83 - 7.72 (m, 5H), 7.63 - 7.55 (m, 1H), 7.32 - 7.21 (m, 1H), 6.60 (s, 1H), 4.54 (dd, J = 12.1, 4.0 Hz, 1H), 4.46 - 4.37 (m, 1H), 4.26 (dd, J = 16,3, 2.5 Hz, 1H), 4.12 (dd, J = 16.4, 7.2 Hz, 1H), 4.08 - 3.99 (m, 1H), 3.41 - 3.33 (m, 1H), 2.17 (s, 3H). E4. PREPARATION OF FINAL COMPOUND 6
Figure imgf000065_0001
10% Pd/C (100 mg, 0.08 mmol) was added to a solution of intermediate 18 (2 g, 4.39 mmol) in a mixture of EtOH/EtOAc (15 mL) under nitrogen atmosphere at 0 °C. The mixture was stirred under hydrogen atmosphere at rt for 16 h. The reaction was filtered through a pad of celite® and the solvent was evaporated in vacuo to yield 1400 mg of the crude product (69% yield, 72% pure).
The crude product (700 mg) was purified by RP-HPLC. Column: Brand Phenomenex; Type Gemini; I.D. (mm) 100 x 30; Particle size Sum (Cl 8) 110A; Installed Gilson 1 Method (MMP3AF) From 70 % of (H2O in 0.1% HCOOH) - 30 % (ACN: MeOH 1: 1) Till 27 % of (H20 in 0.1% HCOOH)- 73 % (ACN: MeOH 1: 1). The fractions were concentrated and dried in vacuo to afford a light yellowish solid that was triturated with DIPE, filtered and dried in vacuo to afford compound 6 (100 mg) as a white solid. 1 H NMR (400 MHz, DMSO) d 11.86 (s, 1H), 8.02 (dd, J = 9.2, 4.7 Hz, 1H), 7.73 (dd, J
= 9.4, 3.0 Hz, 1H), 7.68 (d, J = 8.7 Hz, 2H), 7.56 (td, J = 8.7, 3.0 Hz, 1H), 7.43 (d, J = 8.1 Hz, 2H), 4.64 (dd, J = 12.1, 3.9 Hz, 1H), 4.45 (dd, J = 10.3, 3.9 Hz, 1H), 4.23 (dt, J = 22.1, 14.2 Hz, 3H), 2.36 (s, 3H). NH missed
The following compounds were synthesized by the method already reported.
Figure imgf000066_0001
Figure imgf000067_0001
Figure imgf000068_0002
The following compounds are/were also prepared in accordance with the methods described herein:
Compound 19
Figure imgf000068_0001
Figure imgf000069_0001
Figure imgf000070_0001
Figure imgf000071_0001
Figure imgf000072_0001
Figure imgf000073_0001
Figure imgf000074_0001
Figure imgf000075_0001
Figure imgf000076_0001
Figure imgf000077_0001
Figure imgf000078_0001
Figure imgf000079_0001
Further Characterizing data table
Where MP = melting point. (DSC) using a Metller Toledo DSC3 SFR System, (MP) using a Mettler Toledo MP50.
Figure imgf000080_0001
Figure imgf000081_0001
Figure imgf000082_0001
Figure imgf000083_0001
Figure imgf000084_0001
Figure imgf000084_0002
Figure imgf000085_0001
Figure imgf000086_0001
Pharmacological Examples In the tests described below, individual compounds of the invention/examples (or combinations containing such compounds, for instance cytochrome bd inhibitors of the invention/examples in combination with one or more other inhibitor(s) of a (different) target of the electron transport chain of mycobacteria, as described herein) may be tested. For instance, in Tests 1 to 4, combinations may be tested (e.g. combinations of test cytochrome bd compounds with known cytochrome be inhibitors, such as Q203 and Compound X). Where a control cytochrome bd compound is employed, then CK- 2-63 is employed. The compound Q203 (cytochrome bcl inhibitor) may be prepared in accordance with the procedures in J. Medicinal Chemistry, 2014, 57 (12), pp 5293-5305, as well as, in WO 2011/113606 (see Compound 289 “6-chloro-2-ethyl-/V-(4-(4-(4- (trifluoromethoxy)phenyl)piperidin- 1 -yl)benzyl)imidazo[ 1 ,2-a]pyridine-3- carboxamide”).
Compound X is 6-chloro-2-ethyl-/V-({4-[2-(trifluoromethanesulfonyl)-2- azaspiro[3.3]heptan-6-yl]phenyl }methyl)imidazo[ 1 ,2-α]pyridine-3-carboxamide, which is described as Compound 154 of WO 2017/001660 and may be prepared according to the procedures described therein.
CK-2-63 may be prepared in accordance with the procedures disclosed in WO 2017/103615 (see experimental and the disclosures therein, referring to WO 2012/2069856, where an experimental procedure is provided for “3-methyl-2-(4-(4- (trifluoromethoxy)phenoxy)phenyl)quinolin-4(lH)-one”).
MIC determination against M. tuberculosis : test 1
Test compounds and reference compounds were dissolved in DMSO and 1 mΐ of solution was spotted per well in 96 well plates at 200x the final concentration. Column 1 and column 12 were left compound-free, and from column 2 to 11 compound concentration was diluted 3-fold. Frozen stocks of Mycobacterium tuberculosis strain EH4.0 expressing green-fluorescent protein (GFP) were previously prepared and titrated. To prepare the inoculum, 1 vial of frozen bacterial stock was thawed to room temperature and diluted to 5x10 exp5 colony forming units per ml in 7H9 broth. 200 mΐ of inoculum, which corresponds to 1x10 exp5 colony forming units, were transferred per well to the whole plate, except column 12. 200m1 7H9 broth were transferred to wells of column 12. Plates were incubated at 37°C in plastic bags to prevent evaporation. After 7 days, fluorescence was measured on a Gemini EM Microplate Reader with 485 excitation and 538 nm emission wavelengths and IC50 and/or pICso values (or the like, e.g. IC50, IC90, pICgo, etc) were (or may be) calculated. MIC determination against M. tuberculosis: test 2
Appropriate solutions of experimental and reference compounds were made in 96 well plates with 7H9 medium. Samples of Mycobacterium tuberculosis strain H37Rv were taken from cultures in logarithmic growth phase. These were first diluted to obtain an optical density of 0.3 at 600 nm wavelength and then diluted 1/100, resulting in an inoculum of approximately 5x10 exp5 colony forming units per ml. IOOmI of inoculum, which corresponds to 5x10 exp4 colony forming units, wer transferred per well to the whole plate, except column 12. Plates were incubated at 37°C in plastic bags to prevent evaporation. After 7 days, resazurin was added to all wells. Two days later, fluorescence was measured on a Gemini EM Microplate Reader with 543 excitation and 590 nm emission wavelengths and MIC50 and/or pICso values (or the like, e.g. IC50, IC90, PIC90, etc) were (or may be) calculated.
Time kill kinetics assays: test 3
Bactericidal or bacteriostatic activity of the compounds can be determined in a time kill kinetic assay using the broth dilution method. In this assay, the starting inoculum of M. tuberculosis (strain H37Rv and H37Ra) is 106 CFU / ml in Middlebrook (lx) 7H9 broth. The test compounds (cyt bd inhibitors) are tested in combination with a cyt be inhibitor (for example Q203 or Compound X) at the concentration ranging from 10- 30mM to 0.9-0.3mM respectively. Tubes receiving no antibacterial agent constitute the culture growth control. The tubes containing the microorganism and the test compounds are incubated at 37 °C. After 0, 1, 4, 7, 14 and 21 days of incubation samples are removed for determination of viable counts by serial dilution (10° to 1(T6) in Middlebrook 7H9 medium and plating (100 mΐ) on Middlebrook 7H11 agar. The plates are incubated at 37 °C for 21 days and the number of colonies are determined. Killing curves can be constructed by plotting the log10CFU per ml versus time. A bactericidal effect of a cytochrome be and cytochrome bd inhibitor (either alone or in combinaton) is commonly defined as 2-log 10 decrease (decrease in CFU per ml) compared to Day 0. The potential carryover effect of the drugs is limited by using 0.4% charcoal in the agar plates, and by serial dilutions and counting the colonies at highest dilution possible used for plating.
Phenotypic assay to determine the O2 consumption rate of Mycobacterium tuberculosis', test 4
The aim of this assay is to evaluate the O2 consumption rate of Mycobacterium tuberculosis (Mtb) bacilli after inhibition of cyt bcl and cyt bd, using extracellular flux technology. Inhibition of cyt bcl (e.g. using known inhibitors such as Q203 or Compound X) forces the bacillus to use the less energetically efficient terminal oxidase cyt bd. The inhibition of cyt bd will cause a significant decrease O2 consumption. A sustained decrease of O2 consumption under membrane potential disrupting conditions, via the addition of the uncoupler CCCP, will show to the efficacy of the cyt bd inhibitor.
The oxygen consumption rate (OCR) of Mtb (stain H37Ra) bacilli adhered to the bottom of a Cell-Tak (BD Biosciences) coated XF cell culture microplate (Agilent), at 5x 106 bacilli per well, was measured using the Agilent Seahorse XFe96. Prior to the assay Mtb bacilli are cultured for two days to an OD600 ~0.7-0.9 in liquid medium, using 7H9 supplemented with 10% and 0,02% Tyloxapol. The assay media used is unbuffered 7H9 only supplemented with 0.2% glucose. For this assay the Compound X (final concentration of 0.9 mM, Compound X), is used to inhibit cyt bcl and the cyt bd inhibitor, CK-2-63 (final concentration of 10 mM), is used as a positive control. The uncoupler CCCP is used at a final concentration of 1 mM.
In general, four basal OCR measurements are taken before the automatic addition of Compound X, through drug port A of the sensor cartridge, after which seven more OCR measurements are taken to allow enough time for the inhibition of cyt be 1. Next the cyt bd test compounds (final concentration of 10 mM), as well as the positive and negative controls (assay media with a final DMSO concentration of 0.4%), are added (drug port B) followed by seven OCR measurements. Finally, CCCP is added followed by three OCR measurements, this is done twice (drug ports C and D). For the control’s measurements are performed in eight replicate wells and for the assay compounds six replicate wells per condition. Compounds are scored for their sustained inhibition of cyt bd in relation to the positive and negative controls.
Further Phenotypic assay: using a cytochrome be knock-out TB strain and MIC determination against M. tuberculosis·, test 5
Appropriate solutions of experimental and reference compounds were made in 384 well plates with 7H9 medium. Samples of Mycobacterium tuberculosis strain H37Rv ActaE- AqcrCAB (Nat Commun 10. 4970, 2019, https://doi.org/10.1038/s41467-Q19-12956-2I were taken from cultures in logarithmic growth phase. These were first diluted to obtain an optical density of 0.4 at 600 nm wavelength and then diluted 1/150, resulting in an inoculum of approximately 5x10 exp5 colony forming units per ml. 30m1 of inoculum, which corresponds to 5x10 exp5 colony forming units, were transferred per well to the whole plate, except columns 23-24. Plates were incubated at 37°C, in an extra humidified incubator, in plastic bags to prevent evaporation. After 10 days, optical density at 620 nm wavelength was measured on an EnVision 2105 Multimode Plate Reader with a Photometric 620/8 excitation filter, and MIC50 and/or pICso values (or the like, e.g. IC50, IC90, rK¾o, etc) were (or may be) calculated. Further Phenotypic assay: using a cytochrome be knock-out TB strain and MIC determination against M. tuberculosis·, test 6
Appropriate solutions of experimental and reference compounds were made in 384 well plates with 7H9 medium. Samples of Mycobacterium tuberculosis strain H37Rv ActaE- AqcrCAB (Nat Commun 10. 4970. 2019. https://doi.org/ 10.1038/s41467-019- 12956-2) were taken from frozen stock
Figure imgf000090_0001
The stock is diluted to get an inoculum of 5c10L5 colony forming units per ml. 30m1 of inoculum, which corresponds to 5x10 exp5 colony forming units, were transferred per well to the whole plate, except the first 2 and the last 2 columns and the first 2 and the last 2 rows. These wells are filled with media to avoid evaporation. Plates were incubated at 37°C, in an extra humidified incubator, in plastic bags to prevent evaporation. After 10 days, optical density at 620 nm wavelength was measured on an EnVision 2105 Multimode Plate Reader with a Photometric 620/8 excitation filter, and MICso and/or pICso values (or the like, e.g. IC50, IC90, pICgo, etc) were (or may be) calculated.
Pharmacological Results
Biological Data - Example A Compounds of the invention/examples (or combinations, e.g. compounds of the invention/examples in combination with one or more other inhibitors of a target of the electron transport chain), for example when tested in any of Tests 1 to 3, may display activity. Biological Data - Example B
Compounds of the examples were tested in Test 4 described above (in section “Pharmacological Examples”; O2 consumption rate testing), together with Compound X - a known cytochrome be inhibitor - as described above, and the following results were obtained:
Figure imgf000090_0002
Figure imgf000091_0001
Biological Data - Example C
Compounds of the examples are tested in Test 3 (the kill kinetics) described above, obtaining results expressed as a log reduction in CFUs per ml as compared to Day 0.
Biological Data - Example D
Compounds of the examples are/were re-tested in Test 5 and/or Test 6 described above. The following results were obtained in Test 5
Figure imgf000091_0002
The following further results were obtained in Test 6:
Figure imgf000091_0003
Figure imgf000092_0001
Further Data
The compounds of the invention/examples may have advantages associated with in vitro potency, kill kinetics (i.e. bactericidal effect) in vitro, PK properties, food effect, safety/toxicity (including liver toxicity, coagulation, 5-LO oxygenase), metabolic stability, Ames II negativity, MNT negativity, aqueous based solubility (and ability to formulate) and/or cardiovascular effect e.g. on animals (e.g. anesthetized guinea pig). The data below that was generated/calculated may be obtained using standard methods/assays, for instance that are available in the literature or which may be performed by a supplier (e.g. Microsomal Stability Assay - Cyprotex, Mitochondrial toxicity (Glu/Gal) assay - Cyprotex, as well as literature CYP cocktail inhibition assays). Mitotoxicity data:
Figure imgf000092_0002
Figure imgf000093_0001
Figure imgf000094_0001
Figure imgf000095_0001
Figure imgf000096_0001
Figure imgf000097_0001
In the table above, “negative” [1] means that in the test, it was found to have low mitotoxicity (and hence no mitotoxicity alerts), “positive” [3] means that there were some mitotoxicity alerts and “inconclusive” [0] means that no accurate conclusion could be drawn, e.g. due to issues with the compound being tested in the assay, e.g. solubility or precipitation issues (e.g. compound may not be soluble enough or may precipitate).
In view of the data above, compounds of the invention/examples may be found to be advantageous as no mitotoxicity alerts were observed (e.g. in the Glu/Gal assay).

Claims

1. A compound of formula (I)
Figure imgf000098_0001
wherein
R1 represents C1-6 alkyl, -Br, hydrogen or -C(O)N(Rql)Rq2;
Rql and Rq2 independently represent hydrogen or C1-6 alkyl, or may be linked together to form a 3-6 membered carbocylic ring optionally substituted by one or more C1-3 alkyl substituents;
Sub represents one or more optional substituents selected from halo (e.g. fluoro), -CN, C1-6 alkyl and -O-C1-6 alkyl (wherein the latter two alkyl moieties are optionally substituted by one or more fluoro atoms); the “A” ring represents a 6-membered ring which may be aromatic or non-aromatic, or it represents a 5-membered aromatic ring containing one heteroatom (e.g. a sulfur heteroatom); the “B” ring represents a 5-membered heteroaryl ring, which contains between one and four heteroatoms (e.g. selected from nitrogen, oxygen and sulfur), and which “B” ring is optionally substituted by one or more substituents selected from halo and C1-6 alkyl (itself optionally substituted by one or more fluoro atoms);
L1 represents an optional linker group, and hence may be a direct bond or -C(Rxl)(Rx2);
Rxl and Rx2 independently represent hydrogen or C1-3 alkyl; Z1 represents any one of the following moieties:
(i)
Figure imgf000099_0001
ring C represents a 5-membered aromatic ring containing at least one heteroatom (preferably containing at least one nitrogen atom), and which ring is optionally substituted by one or more substituents independently selected from Rf; ring D represents a 6-membered aromatic ring containing at least one heteroatom (preferably containing at least one nitrogen atom), and which ring is optionally substituted by one or more substituents independently selected from Rg; Yh represents -[(CH2) 1-4]- (so forming a 3- to 6-membered N-containing ring), and Rh represents one or more optional substituents on such ring;
Ra, Rb, Rc, Rd and Re independently represent hydrogen or a substituent selected from B1; each Rf, each Rg and each Rh (which are optional substituents), when present, independently represent a substituent selected from B 1 ; each B1 independently represents a substituent selected from:
(i) halo;
(ii) -Rd1;
(iii) -ORel;
(iv) -C(O)N(Re2)Re3
(v) -SF5;
(vi) -N(Re4)S(O)2Re5;
(vii) -S(O)2Re5;
Rdl represents C1-6 alkyl, preferably C1-3 alkyl, optionally substituted by one or more halo (e.g. fluoro) atoms;
Re l, Re2, Re3, Re4 and Re5each independently represent hydrogen or C1-6 alkyl optionally substituted by one or more fluoro atoms; or a pharmaceutically-acceptable salt thereof.
2. A compound as claimed in Claim 1, wherein R1 represents C1-3 alkyl such as methyl.
3. A compound as claimed in Claim 1 which is represented as follows:
Figure imgf000101_0001
4. A compound as claimed in any of the preceding claims, wherein the “B” ring and adjacent 6 membered non-aromatic ring in compounds of the invention may be depicted as follows in sub formula (II) (in which the left hand side would be further bound to the requisite quinolinone, or tetrahydro-quinolinone, of formula (I) and the right hand side would be further bound to the L1 group of formula (I)):
Figure imgf000101_0002
wherein: one of X1 and X2 represents N (i.e. there is an essential nitrogen at the ring junction) and the other represents C; the other integers X3, X4 and X5 may represent C (or CH) or a heteroatom (such as N,
O and/or S); and/or none, any one or two of X3, X4 and X3 represents a heteroatom (e.g. N, O and/or S) and the other represents C (or CH).
5, A compound as claimed in any of the preceding claims wherein: L1 represents a direct bond or -C(Rxl)(Rx2)-; Rxl and Rx2 independently represent hydrogen.
6. A compound as claimed in any one of the preceding claims, wherein: none, but preferably, one or two (e.g. one) of Ra, Rb, Rc, Rd and Re represents B1 and the others represent hydrogen; and/or one of Rb Rc and Rd (preferably Rc) represents B1 and the others represent hydrogen.
7. A compound as claimed in any one of the preceding claims, wherein B1 represents a substituent selected from:
(i) Fluoro or chloro;
(i!) C1-6 alkyl, preferably Ci .* alkyl, substituted by one or more fluoro atom;
(iii)
(iv)
(v)
(vi)
(vii)
Figure imgf000102_0001
8. A compound as claimed in any one of the preceding claims, wherein:
Re2 and Re4 independently represent hydrogen;
Rel, Re3 and Re3 each independently represent C 1-3 alkyl (e.g. methyl) substituted by one or more fluoro atoms.
9. A compound as claimed in any one of claims 1 to 8, for use as a pharmaceutical.
10. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and, as active ingredient, a therapeutically effective amount of a compound as defined in any one of claims 1-8.
11. Compound according to any one of claims 1-8 for use in the treatment of tuberculosis.
12. Use of a compound according to any one of claims 1 to 8 for the manufacture of a medicament for the treatment of tuberculosis.
13. A method of treatment of tuberculosis, which method comprises administration of a therapeutically effective/useful amount of a compound according to any one of Claim 1 to 8.
14. A combination of (a) a compound according to any one of claims 1 to 8, and (b) one or more other anti-tuberculosis agent (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor).
15. A product containing (a) a compound according to any one of claims 1 to 8, and (b) one or more other anti-tuberculosis agent (e.g. one or more other inhibitors of the electron transport chain of mycobacteria, for instance a cytochrome be inhibitor, an ATP synthase inhibitor, a NDH2 inhibitor and/or an inhibitor of the menaquinone synthesis pathway, such as a MenG inhibitor), as a combined preparation for simultaneous, separate or sequential use in the treatment of a bacterial infection.
16. A combination or product according to Claim 14 or Claim 15 for use in the treatment of tuberculosis.
17. Use of a combination or product according to Claim 14 or Claim 15 for the manufacture of a medicament for the treatment of tuberculosis.
18. A method of treatment of tuberculosis, which method comprises administration of a therapeutically effective amount of a combination or product according to Claim 14 or Claim 15.
19. Compound according to any one of claims 1-8 for use in enhancement of activity of another anti-tuberculosis agent (as defined in Claim 14 or Claim 15) when employed in combination.
20. A process for the preparation of a compound of formula (I) as claimed in Claim 1, which process comprises:
(i) hydrogenation of a compound of formula (V),
Figure imgf000104_0001
in which the integers are defined in Claim 1.
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