Pyridopyrimidine derivatives as P2X3 inhibitors

Abstract

The present invention relates to compounds that inhibit P2X purinergic receptor 3 (hereinafter referred to as P2X3 inhibitors); in particular, the present invention relates to compounds that are pyridopyrimidine derivatives, methods for preparing such compounds, pharmaceutical compositions containing them, and their therapeutic uses. The compounds of the present invention may be useful in the treatment of many disorders related to P2X3 receptor mechanisms, for example, respiratory diseases including cough, asthma, idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD).

Description

[Technical Field]

[0001] The present invention relates to compounds which inhibit P2X purinoceptor 3 (hereinafter referred to as P2X3 inhibitors); in particular, the present invention relates to compounds which are pyridopyrimidine derivatives, methods for making such compounds, pharmaceutical compositions containing them and their therapeutic uses.

[0002] The compounds of the present invention may be useful in the treatment of a number of disorders associated with P2X3 receptor mechanisms, such as respiratory diseases including cough, asthma, idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD). [Background technology]

[0003] P2X receptors are cell surface ion channels activated by extracellular adenosine 5-triphosphate (ATP). The P2X receptor family is a trimeric assembly composed of seven different subunit subtypes (P2X1-7) that assemble into homomeric and heteromeric channels. All subunits share a common topology that includes an intracellular tail, two transmembrane helices that form the ion channel, and a large extracellular domain containing the ATP-binding site. Homomeric P2X1, P2X2, P2X3, P2X4, P2X5, and P2X7 channels and heteromeric P2X 2 / 3 and P2X 1 / 5The channels have been thoroughly characterized after heterologous expression. P2X receptors are abundantly distributed, and functional responses are found in neurons, glial cells, epithelia, endothelium, bone, muscle, and hematopoietic tissues. In smooth muscle, P2X receptors respond to ATP released from sympathetic motor nerves (e.g., during ejection). In sensory nerves, they are involved in the initiation of afferent signals in several organs (e.g., bladder, intestine) and play an important role in sensing tissue injury and inflammatory stimuli. Paracrine roles for ATP signaling via P2X receptors may exist in the neurohypophysis, ductal glands, airway epithelium, kidney, bone, and hematopoietic tissues. (RA. North: Molecular Physiology of P2X Receptors; Physiol Rev, Vol 82, Oct 2002). All P2X receptors mediate the uptake of Na. + and Ca + They are nonselective cation channels that are permeable to ions and are activated by ATP; however, the pharmacology of receptor subtypes varies with sensitivity to ATP and small molecule antagonists (K Kaczmarek-Hajek et al: Molecular and functional properties of P2X receptors - recent progress and persisting challenges; Purinergic Signalling 8:375-417, 2012).

[0004] In humans, P2X3 receptors have been reported in the heart and spinal cord at the mRNA level and in the DRG, gut (intramural plexus neurons), bladder (urothelium and urothelium) and dental pulp at the protein level (Garcia-Guzman M et al: Molecular characterization and pharmacological properties of the human P2X3 purinoceptor: Brain Res Mol Brain Res. 1997; 47(1-2):59-66).

[0005] The neurophysiological role of P2X3 receptors in airway sensory nerve function is similar to their role in mediating somatic nociception (Undem BJ and Nassenstein C: Airway nerves and dyspnea associated with inflammatory airway disease, Respir Physiol Nerobiol 167: 36-44, 2009). This similarity has given rise to the hypothesis of their involvement in symptoms of airway dysfunction, including cough and bronchial hyperresponsiveness (Ford AP: In pursuit of P2X3 antagonists: novel therapeutics for chronic pain and afferent sensitization, Purinergic signal 8 (suppl 1):3-26, 2012; North RA, Jarvis MF P2X Receptors as Drug Targets; Mol Pharmacol 83:759-769, 2013). P2X3 subunits are also co-localized in many neurons, particularly in the DRG, inferior ganglion, nucleus of the solitary tract and taste buds (Cheung KK, Burnstock G: Localization of P2X3 receptors and coexpression with P2X2 receptors during rat embryonic neurogenesis. J Comp Neurol 443(4):368-382 2002).

[0006] P2X3 antagonists have been proposed for the treatment of diabetic neuropathic pain (Guo J et al: Contributions of purinergic P2X3 receptors within the midbrain periaqueductal gray to diabetes-induced neuropathic pain, J Physiol Sci Jan;65(1):99-104 2015).

[0007] P2X3 and P2X 2 / 3These channels play an important role in the development of arthritis joint hyperalgesia (Teixeira JM et al: P2X3 and P2X2 / 3 Receptors Play a Crucial Role in Articular Hyperalgesia Development Through Inflammatory Mechanisms in the Knee Joint Experimental Synovitis, Mol Neurobiol Oct;54(8):6174-6186, 2017).

[0008] P2X3 is also a potential target for the therapeutic treatment of bladder pain. It has also been proposed as an analgesic target for treating ureteral colic and for facilitating the passage of ureteral stones (Canda AE et al: Physiology and pharmacology of the human ureter: basis for current and future treatments, Urol Int. 78(4):289-98, 2007).

[0009] P2X3 overexpression is associated with poor recurrence-free survival in hepatocellular carcinoma patients, identifying P2X3 as a potential therapeutic target (Maynard JP et al: P2X3 purinergic receptor overexpression is associated with poor recurrence-free survival in hepatocellular carcinoma patients Oncotarget Dec 1;6(38):41162-79, 2015).

[0010] It has been suggested that P2X3 antagonists may improve erectile function recovery (Li CL et al: Effects of intracavernous injection of P2X3 and NK1 receptor antagonists on erectile dysfunction induced by spinal cord transection in rats, Andrologia . Feb;47(1):25-9, 2015).

[0011] ATP enhances citric acid- and histamine-induced cough in preclinical models, but this effect can be reduced by a P2X3-selective antagonist (Kamei J and Takahashi Y: Involvement of ionotropic purinergic receptors in the histamine-induced enhancement of the cough reflex sensitivity in guinea pigs, Oct 10;547(1-3):160-4, 2006). In humans, local delivery of ATP initiates cough and bronchospasm (Basoglu OK et al: Effects of aerosolized adenosine 5'-triphosphate vs. adenosine 5'-monophosphate on dyspnea and airway caliber in healthy nonsmokers and patients with asthma, Chest. Oct;128(4):1905-9, 2005).

[0012] The therapeutic promise of P2X3 antagonists for the treatment of chronic cough was first recognized by Ford and Undem (Ford AP, Undem BJ: The therapeutic promise of ATP antagonism at P2X3 receptors in respiratory and urological disorders, Front Cell Neurosci, Dec 19;7:267, 2013). P2X3 is expressed by airway afferent nerves and mediates the hypersensitivity of the cough reflex, which is dramatically reduced by the oral P2X3 antagonist, AF-219 (Abdulqawi et al: P2X3 receptor antagonist (AF-219) in refractory chronic cough: a randomized, double-blind, placebo-controlled phase 2 study, Lancet 385, 1198-205, 2015).

[0013] ATP is a P2X 2 / 3 P2X2 is an important neurotransmitter in the taste system, acting primarily through heteromultimeric receptors. Consequently, disruption of taste function may be an unintended consequence of the use of purinergic P2X3 antagonists to treat pain, chronic cough, and other conditions (Vandenbeuch A et al: Role of the ectonucleotidase NTPDase2 in taste bud function, Proc Natl Acad Sci USA, Sep 3;110(36):14789-94, 2013. Bo X et al: Localization of ATP-gated P2X2 and P2X3 receptor immunoreactive nerves in rat taste buds, Neuroreport, 10(5):1107-11, 1999).

[0014] P2X3 and / or P2X 2 / 3 A wide variety of compounds have been described in the literature as inhibitors.

[0015] WO 2017058645 (Afferent Pharmaceuticals INC) discloses a diaminopyrimidine P2X3 / P2X3 inhibitor for the treatment of disorders involving cough, chronic cough and urge to cough, including cough associated with a respiratory disease or disorder, by administering an effective amount of the disclosed compound. 2 / 3 The use of antagonists is disclosed, however, pyridopyrimidine derivatives are not disclosed.

[0016] WO 2017011729 (Patara Pharma LLC) discloses a combination of cromolyn or a pharmaceutically acceptable salt thereof and P2X3 and / or P2X for the treatment of pulmonary diseases and conditions. 2 / 3 The use of receptor antagonists as antitussive agents has been disclosed.

[0017] WO2016091776 (Evotec AG) discloses 1,3-thiazol-2-yl substituted benzamide compounds that inhibit the P2X3 receptor and pharmaceutical compositions containing such compounds, and the use of the compounds for the treatment of several disorders, including respiratory diseases.

[0018] International Publication No. 2016088838 (Shionogi Pharmaceuticals) describes novel P2X3 and / or P2X 2 / 3 Purine derivative compounds having receptor antagonistic activity have been disclosed.

[0019] International Publication No. 2016084922 (Shionogi Pharmaceuticals) describes novel P2X3 and / or P2X 2 / 3 Triazine derivative compounds having receptor antagonistic activity have been disclosed.

[0020] WO2008123963 (Renovis) relates to fused heterocyclic compounds of tetrahydropyrido[4,3-d]pyrimidines and pharmaceutical compositions containing such compounds. Methods for preventing and / or treating several disorders, such as neurodegenerative disorders, pain, asthma, and autoimmune disorders, by administering the disclosed compounds are also provided.

[0021] WO2008130481 (Renovis) discloses 2-cyanophenyl fused heterocyclic compounds of the tetrahydropyrido[4,3-d]pyrimidine class and pharmaceutical compositions containing such compounds.

[0022] WO 2010033168 (Renovis) describes a series of phenyl or pyridyl substituted benzamides believed to be useful in the treatment of diseases associated with the P2X purinergic receptor, and more particularly, P2X3 receptors and / or P2X 2 / 3 Receptor antagonists have been disclosed, but pyridopyrimidine derivatives have not.

[0023] WO2009110985 (Renovis) relates to phenyl and pyridyl substituted benzamide compounds and pharmaceutical compositions containing such compounds, but excludes thiazole substituted benzamides, which are compounds different from the compounds of the present invention.

[0024] WO 2008000645 (Roche) describes compounds containing P2X3 and / or P2X4 useful for the treatment of urogenital, pain, gastrointestinal and respiratory diseases, conditions and disorders. 2 / 3 Receptor tetrazole-substituted aryl amide compound antagonists are disclosed.

[0025] Novel and pharmacologically improved P2X3 and / or P2X inhibitors in many therapeutic areas, e.g., particularly in respiratory diseases. 2 / 3 The potential exists for the development of inhibitors.

[0026] Notwithstanding the prior art cited above, there is still a need for novel pyridopyrimidine compounds, preferably with selective action on the P2X3 receptor, for the treatment of diseases associated with the P2X3 receptor in many therapeutic areas, for example, in particular respiratory diseases.

[0027] Notably, the prior art does not describe or suggest the pyridopyrimidine derivative compounds of the present invention of general formula (I) that provide a solution to the above-mentioned needs. Summary of the Invention

[0028] The present invention relates to a compound of formula (I) [ka] [During the ceremony, X1, X2 and X3 are independently CH or N; Z is H or selected from the group consisting of (C1-C4) alkyl-, heteroaryl, aryl, wherein any of said heteroaryl and aryl are optionally selected from (C1-C3) alkyl, halo, CN, (R A R B )NC(O)—; R1 is H; R2 is selected from the group consisting of heteroaryl(C1-C4)alkyl-, (C3-C8)heterocycloalkyl-(C1-C6)alkyl-, wherein any of said alkyl, heteroaryl, and heterocycloalkyl are optionally selected from (C1-C3)alkyl, halo, R A O(C1-C4)alkylene-, (C1-C6)haloalkyl, R A O-; R A and R B is, at each occurrence, independently H or (C1-C4)alkyl-; R A and R B may optionally contain, together with the nitrogen atom to which they are attached, a further heteroatom which is nitrogen, optionally RC (O)C-substituted 6-membered saturated heterocyclic monocyclic ring systems can be formed; R C is (C1-C6) alkyl; J is H or (R A R B )N- This refers to a compound of the formula:

[0029] In a second aspect, the present invention refers to a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof, alone or in combination with one or more other active ingredients, in admixture with one or more pharmaceutically acceptable carriers or excipients.

[0030] In a third aspect, the present invention provides a compound of formula (I) for use as a pharmaceutical.

[0031] In a further aspect, the present invention provides the use of a compound of formula (I) for use in the treatment of any disease in which the P2X3 receptor is involved.

[0032] In a further aspect, the present invention refers to a compound of formula (I) for use in the prevention and / or treatment of cough, subacute or chronic cough, refractory cough, idiopathic chronic cough, cough after viral infection, iatrogenic cough, asthma, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and cough associated with respiratory diseases such as COPD, asthma and bronchospasm.

[0033] In a further aspect, the present invention relates to a compound of formula IIIa [ka] [During the ceremony, X is N or CH; R7 is OH and / or Cl; R8 is a halo. This refers to a compound of the formula:

[0034] In a further aspect, the present invention refers to the use of Formula (IIIa) as an intermediate in the preparation of compounds of Formula (I).

[0035] Detailed Description of the Invention The present invention relates to a compound of formula (I) [ka] wherein X1, X2, and X3 are independently CH or N; Z is H or selected from the group consisting of (C1-C4) alkyl-, heteroaryl, aryl, wherein any of said heteroaryl and aryl are optionally selected from (C1-C3) alkyl, halo, CN, (R A R B )NC(O)—; R1 is H; R2 is selected from the group consisting of heteroaryl(C1-C4)alkyl-, (C3-C8)heterocycloalkyl-(C1-C6)alkyl-, wherein any of said alkyl, heteroaryl, and heterocycloalkyl are optionally selected from (C1-C3)alkyl, halo, R A O(C1-C4)alkylene-, (C1-C6)haloalkyl, R A O-; R A and R B is, in each occurrence, independently H or (C-C)alkyl-; or R A and R B may, together with the nitrogen atom to which they are attached, optionally contain a further heteroatom which is nitrogen; optionally R C (O)C-substituted 6-membered saturated heterocyclic monocyclic ring systems can be formed; R C is (C1-C6) alkyl; J is H or (R A R B )N-] The present invention relates to the compound

[0036] definition As used herein, the term "pharmaceutically acceptable salts" refers to derivatives of the compounds of formula (I), wherein the parent compound is suitably modified by converting any free acid or basic group, if present, with any base or acid, into a corresponding addition salt that is conventionally intended to be pharmaceutically acceptable.

[0037] Thus, suitable examples of such salts include inorganic or organic acid addition salts of basic residues such as amino groups, and inorganic or organic base addition salts of acidic residues such as carboxyl groups.

[0038] Cations of inorganic bases which may be suitably used to prepare salts include ions of alkali metals or alkaline earth metals such as potassium, sodium, calcium or magnesium.

[0039] Compounds obtained by reacting the primary compound that functions as a base with an inorganic or organic acid to form a salt include, for example, salts of hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, methanesulfonic acid, camphorsulfonic acid, acetic acid, oxalic acid, maleic acid, fumaric acid, succinic acid, and citric acid.

[0040] As used herein, the term "halogen" or "halogen atom" includes fluorine, chlorine, bromine and iodine atoms, preferably chlorine or fluorine.

[0041] The term "(C x -C y ")Alkyl" refers to a straight or branched chain alkyl group having from x to y carbon atoms. Thus, when x is 1 and y is 6, for example, the term includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, and n-hexyl.

[0042] As used herein, the term "(C x -C y) alkylene" refers to a C alkylene having a total of two unsatisfied valences, such as a divalent methylene radical. x -C y It refers to an alkyl group.

[0043] The expression "(C x -C y )haloalkyl" means "C )haloalkyl" as defined above x -C y "Alkyl" refers to an "alkyl" group in which one or more hydrogen atoms are replaced with one or more halogen atoms, which may be the same or different.

[0044] Therefore, the above "(C x -C y Examples of "haloalkyl" groups include halogenated, polyhalogenated, and fully halogenated alkyl groups in which all hydrogen atoms are replaced with halogen atoms, such as trifluoromethyl, difluoromethyl, and trifluoroethyl groups.

[0045] Synonymously, the terms "(C-C)hydroxyalkyl" or "(C-C)aminoalkyl" refer to a "(C-C)alkyl" group, as defined above, in which one or more hydrogen atoms have been replaced by one or more hydroxy (OH) or amino groups, respectively. Examples of these include hydroxymethyl, aminomethyl, dimethylaminopropyl, etc.

[0046] As used herein, unless otherwise indicated, aminoalkyl refers to one or more amino groups (—NR A R B ) (i.e., a "(C1-C6) alkyl" group). Thus, an example of an aminoalkyl is R A R B and monoaminoalkyl groups such as N-(C1-C6) alkyl.

[0047] The substituent R as defined above and below A and R B About R A and R BWhen these groups, together with the nitrogen atom to which they are attached, form a 5- or 6-membered heterocyclic radical, at least one additional ring carbon atom in the heterocyclic radical can be optionally substituted with at least one heteroatom (e.g., N, S, or O) and / or can have an -oxo (=O) substituent. It is understood that the heterocyclic radical can be optionally further substituted at any available position in the ring, i.e., on a carbon atom or on any heteroatom available for substitution. Substitution on a carbon atom includes spirodisubstitution and substitution on two adjacent carbon atoms, thus forming an additional 5- or 6-membered heterocyclic ring in either case. Examples of such heterocyclic radicals are 1-pyrrolidinyl, 1-piperidinyl, 1-piperazinyl, 4-methylpiperazinyl, piperazin-4-yl-2-one, 4-morpholinyl, morpholinyl-3-one, and 1-(piperazin-1-yl)ethenone.

[0048] The term "(C x -C y ")Cycloalkyl" refers to a saturated cyclic hydrocarbon group containing the indicated number of ring carbon atoms. Examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl.

[0049] The term "aryl" refers to a monocyclic carbocyclic ring system having 6 atoms, in which the ring is aromatic. Examples of suitable aryl monocyclic ring systems include, for example, phenyl.

[0050] The term "heteroaryl" refers to a monocyclic or bicyclic aromatic radical containing one or more heteroatoms selected from S, N, and O, including two such monocyclic rings or one such monocyclic ring and one monocyclic aryl ring covalently fused together. Examples of suitable 5- and 6-membered heteroaryls are thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, isothiazolyl, pyrazolyl, oxazolyl, isoxazolyl, isothiazolyl, triazolyl, thiadiazolyl, oxadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, tetrazolyl, and triazinyl.

[0051] The term "heterocyclyl" or "heterocyclic" refers to a saturated monocyclic, bicyclic, or tricyclic non-aromatic radical containing one or more heteroatoms selected from S, N, and O. In the case of bicyclic heterocyclic systems, fused, spiro, and bridged bicyclic systems are included within the scope of the term.

[0052] The term "(C x -C y "Heterocycloalkyl" refers to a saturated or partially unsaturated monocyclic (C) heterocycloalkyl in which at least one carbon atom is replaced with at least one heteroatom (e.g., N, S, or O) or has an -oxo (=O) substituent. x -C y ) cycloalkyl groups. Said heterocycloalkyl (i.e., heterocyclic radical or group) may be optionally further substituted at available positions on the ring, i.e., on a carbon atom or on any heteroatom available for substitution. Substitution on a carbon atom includes spirodisubstitution and substitution on two adjacent carbon atoms, thus forming an additional 5- to 6-membered heterocyclic ring in either case. (C x -C y ) Examples of heterocycloalkyl are represented by pyrrolidinyl, imidazolidinyl, thiazolidinyl, piperazinyl, piperidinyl, morpholinyl, thiomorpholinyl, dihydro- or tetrahydropyridinyl, tetrahydrothiophenyl, azetidinyl, oxetanyl, tetrahydropyranyl, pyranyl, 2H- or 4H-pyranyl, dihydro- or tetrahydrofuranyl, dihydroisoxazolyl, pyrrolidin-2-one-yl, dihydropyrrolyl radicals, and the like.

[0053] Specific examples of said heterocyclic radicals are tetrahydrothiophene 1,1-dioxide, 3,3-difluoropyrrolidinyl, 1-pyrrolidinyl, 1-methyl-2-pyrrolidinyl, 1-piperidinyl, 1-piperazinyl, 4-morpholinyl.

[0054] The expressions "aryloxyl" and "aryl(C-C)alkoxyl," as well as "heteroaryloxyl" and "heteroaryl(C-C)alkoxyl," refer to an aryl or heteroaryl group attached via an oxygen bridge and an attached aryl-alkoxyl or heteroaryl-alkoxyl group. Examples of such groups are phenyloxy, benzyloxy, and pyridinyloxy, respectively.

[0055] The term "aryl(C1-C6)alkyl" refers to an aryl ring attached to a straight or branched alkyl group containing from 1 to 6 carbon atoms, such as a phenylmethyl (i.e., benzyl), phenylethyl, or phenylpropyl group.

[0056] A term where z and k are integers (C z -C k ) heterocycloalkyl-(C x -C y ) Alkyl refers to a heterocyclic ring attached to a straight or branched alkyl group having x to y carbon atoms.

[0057] Similarly, the term "heteroaryl (C x -C y ) alkyl" or "aryl (C x -C y ")Alkyl" refers to a heteroaryl or aryl ring attached to a straight or branched alkyl group having x to y carbon atoms.

[0058] The expression "ring system" refers to a monocyclic, bicyclic or polycyclic ring system, which may be saturated, partially unsaturated or unsaturated, aryl, (C3-C 10 )cycloalkyl, (C3-C6)heterocycloalkyl or heteroaryl.

[0059] The terms "group," "radical," "fragment," or "substituent" are synonymous and are intended to refer to a functional group or molecular fragment that can be attached to a bond or another fragment or molecule. Thus, by way of example, the term "heterocyclic radical" herein refers to a monocyclic or bicyclic saturated or partially saturated heterocyclic moiety (group, radical), preferably a 4- to 11-membered monocyclic radical, in which at least one additional ring carbon atom may optionally be replaced with at least one additional heteroatom independently selected from N, S, or O, and / or may have an -oxo (=O) substituent, and the heterocyclic radical may optionally further include spirodisubstitution and substitution on two adjacent or vicinal atoms to form an additional 5- to 6-membered cyclic or heterocyclic, saturated, partially saturated, or aromatic ring. Examples of such heterocyclic radicals include 1-pyrrolidinyl, 1-piperidinyl, 1-piperazinyl, 4-morpholinyl, and the like.

[0060] An empty line ("-") between two letters or symbols is meant to represent a point of attachment for a substituent. When represented diagrammatically, the point of attachment in a cyclic functional group is indicated by a dot ("·") located on one of the available ring atoms where the functional group can be attached to a bond or other fragment of the molecule.

[0061] An oxo moiety is represented by (O) as an alternative to other common representations, such as (=O). Thus, for general formulas, a carbonyl group is represented herein as -C(O)-. Generally, bracketed groups are side groups and are not included in the chain, and brackets are used when considered useful to avoid ambiguity in linear chemical formulas; for example, a sulfonyl group -SO- may be represented as -S(O)- to avoid ambiguity with, for example, a sulfinic group -S(O)O-.

[0062] Whenever a basic amino group or a quaternary ammonium group is present in the compound of formula I, a physiologically acceptable anion may be present selected from chloride, bromide, iodide, trifluoroacetate, formate, sulfate, phosphate, methanesulfonate, nitrate, maleate, acetate, citrate, fumarate, tartrate, oxalate, succinate, benzoate, p-toluenesulfonate, pamoate, and naphthalenedisulfonate.Similarly, in the presence of an acidic group such as a COOH group, the corresponding physiological cationic salts also exist, including, for example, alkali metal or alkaline earth metal ions.

[0063] It will be appreciated that when compounds of formula (I) contain one or more stereocenters they may exist as optical stereoisomers.

[0064] When the compounds according to the present invention have at least one stereocenter, they can exist as enantiomers. When the compounds according to the present invention have two or more stereocenters, they can exist as diastereoisomers. All such single enantiomers, diastereoisomers, and mixtures thereof in any proportion are within the scope of the present invention. The absolute configuration (R) or (S) of the carbon atom containing the stereocenter is assigned according to the Cahn-Ingold-Prelog naming rules based on group priority.

[0065] The present invention further relates to the corresponding deuterated derivatives of the compounds of formula (I).

[0066] All preferred groups or embodiments for compounds of formula I described above and hereinafter may be combined with each other and apply mutatis mutandis.

[0067] In a preferred embodiment, the present invention comprises: X1, X2 and X3 are independently CH or N; Z is selected from heteroaryl, preferably pyridinyl, thiazolyl and thienyl, and aryl, preferably phenyl; wherein said heteroaryl and aryl are optionally substituted with one or more groups selected from (C1-C3) alkyl and halo, preferably methyl, fluorine and chlorine; R1 is H; R2 is heteroaryl(C1-C4)alkyl-, preferably (pyridazyl)methyl, (pyridazyl)ethyl(pyridinyl)methyl, (pyrimidinyl)ethyl, (oxadiazolyl)ethyl, wherein said heteroaryl is optionally substituted with one or more groups selected from (C1-C3)alkyl, halo, and (C1-C6)haloalkyl, preferably methyl, fluorine, and trifluoromethyl; J is H, It relates to compounds of formula (I) as defined above.

[0068] According to a preferred embodiment, the present invention refers to at least one of the compounds listed in Table 1 below and their pharmaceutically acceptable salts. Table 1: List of preferred compounds having formula (I) [Table 1-1] [Table 1-2] [Table 1-3] [Table 1-4] [Table 1-5] [Table 1-6] [Table 1-7]

[0069] In a preferred embodiment, the present invention provides a compound of formula (Ia) wherein X1 is N and X2 and X3 are CH. [ka] [During the ceremony, Z is H or is selected from the group consisting of (C1-C4) alkyl-, heteroaryl, aryl, wherein any of said heteroaryl and aryl are optionally selected from (C1-C3) alkyl, halo, CN, (R A R B )NC(O)—; R1 is H; R2 is selected from the group consisting of heteroaryl(C1-C4)alkyl-, (C3-C8)heterocycloalkyl-(C1-C6)alkyl, wherein any of said alkyl, heteroaryl is optionally selected from (C1-C3)alkyl, halo, R A O(C1-C4)alkylene-, (C1-C6)haloalkyl, R A O-, optionally substituted with one or more groups selected from; R A and R B is, in each occurrence, independently H or (C-C)alkyl-; R A and R B may optionally contain, together with the nitrogen atom to which they are attached, a further heteroatom which is a nitrogen atom, optionally R C (O)C-substituted 6-membered saturated heterocyclic monocyclic ring systems can be formed; R C is (C1-C6) alkyl; J is H or (R A R B )N- The present invention relates to compounds of formula (I) as defined above, represented by

[0070] In a further preferred embodiment, the present invention provides a compound of formula (Ia) Z is H, or (C1-C4) alkyl-, preferably methyl; R A is H and R B is phenyl optionally further substituted with one or more fluorines, (R A R B )N-; heteroaryl which is pyridinyl, thiazolyl, thiophenyl, each of said heteroaryls optionally substituted with one or more groups selected from methyl or chlorine; aryl, preferably phenyl, each of said aryls optionally selected from methyl, fluorine, CN and (R A R B )NC(O)-(wherein, R A and R B is H); selected from the group consisting of: R1 is H; R2 is Heteroaryl(C1-C4)alkyl-, preferably (pyridazyl)methyl, (pyridazyl)ethyl (pyridinyl)methyl, (pyridinyl)ethyl, (pyrimidyl)ethyl, (oxadiazolyl)ethyl, heteroaryl(C1-C6)alkoxyl, preferably pyridinyloxy; heteroaryl-(C1-C6)hydroxyalkyl, preferably (pyridinyl)ethanol; (C3-C8)heterocycloalkyl-(C1-C6)alkyl, preferably (morpholinyl)ethyl selected from the group consisting of Each of said heteroaryls is optionally selected from methyl, fluorine, trifluoromethyl, R A R is methyl A O-; J is H or (R A R B )N-, where R A and R Btogether with the nitrogen atom to which they are attached form a 6-membered saturated heterocyclic monocyclic ring system which may optionally contain a further heteroatom which is a nitrogen atom, said heterocyclic radical then being R C R is methyl C (O)C-, optionally further substituted A compound.

[0071] According to a preferred embodiment, the present invention refers to at least one of the compounds listed in Table 2 below and their pharmaceutically acceptable salts. Table 2: List of preferred compounds having formula (Ia) [Table 2-1] [Table 2-2] [Table 2-3] [Table 2-4] [Table 2-5] [Table 2-6] [Table 2-7] [Table 2-8] [Table 2-9]

[0072] In a further preferred embodiment, the present invention provides a compound of formula (Ia) Z is selected from the group consisting of heteroaryl, aryl, wherein any of said heteroaryl and aryl may be optionally substituted with one or more groups selected from (C1-C3) alkyl, halo; R1 is H; R2 is selected from the group consisting of heteroaryl(C1-C4)alkyl, wherein any of said alkyl, heteroaryl may be optionally substituted with one or more groups selected from (C1-C3)alkyl, halo, (C1-C6)haloalkyl, -oxo; J is H, A compound.

[0073] According to a preferred embodiment, the present invention refers to at least one of the compounds listed in Table 3 below and their pharmaceutically acceptable salts. Table 3: List of preferred compounds having formula (Ia) [Table 3-1] [Table 3-2] [Table 3-3]

[0074] In a further preferred embodiment, the present invention provides a compound of formula (Ia) Z is selected from the group consisting of phenyl, pyridinyl, and thienyl, wherein any of said phenyl, pyridinyl, and thienyl is optionally substituted with one or more groups selected from methyl and fluorine; R1 is H; R2 is selected from the group consisting of heteroaryl(C1-C2)alkyl, wherein any said heteroaryl is optionally substituted with one or more groups selected from methyl, fluorine, and trifluoromethyl; J is H, A compound.

[0075] According to a preferred embodiment, the present invention refers to at least one of the compounds listed in Table 4 below and their pharmaceutically acceptable salts. Table 4: List of preferred compounds having formula (Ia) [Table 4-1] [Table 4-2]

[0076] In a further preferred embodiment, the present invention provides a compound of formula Ib [ka] [During the ceremony, X2 and X3 are independently CH or N; Z is selected from the group consisting of heteroaryl and aryl, wherein any said aryl and heteroaryl may be optionally substituted with one or more groups selected from (C1-C3) alkyl, halo; R1 is H; R2 is selected from the group consisting of heteroaryl(C1-C4)alkyl-, wherein any said alkyl and heteroaryl is optionally substituted with one or more groups selected from (C1-C3)alkyl, (C1-C6)haloalkyl; J is H] wherein X1 is CH as defined above.

[0077] In a further preferred embodiment, the present invention provides a compound of formula Ib X2 and X3 are independently CH or N; Z is heteroaryl, which is pyridinyl, thiazolyl, each of said heteroaryls optionally further substituted with one or more methyl; aryls that are phenyl, each of said aryls optionally further substituted with one or more fluorines; selected from the group consisting of: R1 is H; R2 is (pyrimidyl)ethyl, (pyridazyl)methyl, (oxadiazolyl)ethyl, wherein the heteroaryl(C1-C4)alkyl- Each of said heteroarylalkyls may be optionally further substituted with one or more groups selected from methyl and trifluoromethyl; J is H, Concerning compounds.

[0078] According to a preferred embodiment, the present invention refers to at least one of the compounds listed in Table 5 below and their pharmaceutically acceptable salts. Table 5: List of preferred compounds having formula (Ib) [Table 5-1] [Table 5-2]

[0079] In a further preferred embodiment, the present invention provides a compound of formula Ib X2 and X3 are independently CH or N; Z is selected from the group consisting of pyridinyl, thiazolyl, and phenyl; wherein said pyridinyl, thiazolyl and phenyl are optionally substituted with one or more groups selected from methyl and fluorine; R1 is H; R2 is selected from the group consisting of (pyrimidyl)ethyl and (pyridazyl)methyl; wherein each of said (pyrimidyl)ethyl and (pyridazyl)methyl is optionally substituted with one or more groups selected from methyl and trifluoromethyl; J is H, A compound.

[0080] According to a preferred embodiment, the present invention refers to at least one of the compounds listed in Table 6 below and their pharmaceutically acceptable salts. Table 6: List of preferred compounds having formula (Ib) [Table 6]

[0081] In a further preferred embodiment, the present invention relates to compounds of formula Ic, wherein X1 and X3 are N and X2 is CH. [ka] [During the ceremony, Z is selected from the group consisting of aryl and heteroaryl, wherein any of said aryl and heteroaryl may be optionally substituted with one or more groups selected from halo and (C1-C3) alkyl; R1 is H; R2 is selected from the group consisting of heteroaryl(C1-C4)alkyl-, wherein any said heteroaryl is optionally substituted with one or more groups selected from (C1-C3)alkyl, (C1-C6)haloalkyl; J is H] The present invention relates to compounds of formula (I) represented by:

[0082] In a further preferred embodiment, the present invention provides Z is aryl, preferably phenyl, each of said aryls optionally substituted with one or more fluorines; R1 is H; R2 is selected from the group consisting of heteroaryl(C1-C4)alkyl-, which is (pyridinyl)methyl, (pyridazyl)methyl, (oxadiazolyl)ethyl, (pyrimidinyl)ethyl; each of said heteroarylalkyls is optionally substituted with one or more groups selected from methyl and trifluoromethyl; J is H, refers to a compound of formula Ic

[0083] According to a preferred embodiment, the present invention refers to at least one of the compounds listed in Table 7 below and their pharmaceutically acceptable salts. Table 7: List of preferred compounds having formula (Ic) [Table 7]

[0084] Compounds of formula (I), including all of the compounds listed above, can be prepared according to the methods shown in the schemes set out below using commonly known methods.

[0085] Scheme 1 [ka] In certain embodiments of the present invention, compound (Ia) can be prepared from intermediate (II) according to Scheme 1.

[0086] Intermediate (III) can be prepared from intermediate (IIa) by deoxyamination mediated by a reagent such as PyBOP or similar in the presence of a suitable amine (reagent 1), or alternatively, from intermediate (IIb) by reaction with a suitable amine (reagent 1).

[0087] Compound (Ia) can be prepared from intermediate (III) by a metal-catalyzed cross-coupling reaction such as a Stille or Suzuki coupling or similar reaction using a suitable reagent (reagent 2), such as an organoboron reagent.

[0088] In another embodiment of the present invention, intermediate (IV) can be prepared from intermediate (IIa) by a metal-catalyzed cross-coupling reaction such as a Stille or Suzuki coupling or similar reaction using a suitable reagent (reagent 2), such as, for example, an organoboron reagent.

[0089] Compound (Ia) can be prepared from intermediate (IV) by a deoxyamination reaction mediated by a reagent such as PyBOP or a similar reagent in the presence of a suitable amine (Reagent 1).

[0090] Intermediate (IVa) may be prepared from intermediate (IV) using a suitable chlorinating reagent such as, for example, phosphorus oxychloride (V) or thionyl chloride.

[0091] Compound (Ia) can be prepared from intermediate (IVa) using an amination reaction with a suitable amine (Reagent 1) in the presence of a base such as, for example, DIPEA.

[0092] Scheme 2 [ka] In another embodiment of the present invention, compound (Ia) can be prepared from intermediate (V) according to Scheme 2.

[0093] Intermediate (VI) can be prepared from intermediate (V) by an amination reaction with a suitable amine (Reagent 1) in the presence of a base such as, for example, DIPEA.

[0094] Intermediate (VII) can be prepared from intermediate (VI) by an amination reaction with a suitable amine (reagent 4) in the presence of a base such as, for example, DIPEA.

[0095] Compound (Ia) can be prepared from intermediate (VII) by a metal-catalyzed cross-coupling reaction such as a Stille or Suzuki coupling or similar reaction using a suitable reagent (reagent 2), such as an organoboron reagent.

[0096] Scheme 3 [ka] In certain embodiments of the present invention, compound (Ib) can be prepared from intermediate (VIII) according to Scheme 3.

[0097] Intermediate (IX) can be prepared from intermediate (VIII) by a metal-catalyzed cross-coupling reaction such as a Stille or Suzuki coupling or similar reaction using a suitable reagent such as an organoboron reagent (reagent 2).

[0098] Compound (Ib) can be prepared from intermediate (IX) by a deoxyamination reaction mediated by a reagent such as PyBOP or a similar reagent in the presence of a suitable amine (reagent 1).

[0099] In another embodiment of the present invention, intermediate (X) can be prepared from intermediate (VIII) by a deoxyamination reaction mediated by a reagent such as PyBOP or a similar reagent in the presence of a suitable amine (reagent 1).

[0100] Compound (Ib) can be prepared from intermediate (X) by a metal-catalyzed cross-coupling reaction such as a Stille or Suzuki coupling or similar reaction using a suitable reagent (reagent 2), such as an organoboron reagent.

[0101] Scheme 4 [ka] In certain embodiments of the present invention, compound (Ib) can be prepared from intermediate (XI) according to Scheme 4.

[0102] Intermediate (XII) can be prepared from intermediate (XI) by a deoxyamination reaction mediated by a reagent such as PyBOP or a similar reagent in the presence of a suitable amine (Reagent 1).

[0103] Compound (Ib) can be prepared from intermediate (XII) by a metal-catalyzed cross-coupling reaction such as a Stille or Suzuki coupling or similar reaction using a suitable reagent (reagent 2), such as an organoboron reagent.

[0104] Scheme 5 [ka] In certain embodiments of the present invention, compound (Ic) can be prepared from intermediate (XIII) according to Scheme 5.

[0105] Intermediate (XIV) can be prepared from intermediate (XIII) by a ring construction method mediated by a suitable reagent such as, for example, triethyl orthoformate.

[0106] Intermediate (XV) can be prepared by a metal catalyzed cross-coupling reaction such as a Stille or Suzuki coupling or similar reaction using a suitable reagent such as an organoboron reagent (reagent 2).

[0107] Intermediate (XVI) can be prepared from intermediate (XV) by a deoxyhalogenation reaction mediated by a reagent such as thionyl chloride or a similar reagent.

[0108] Compound (Ic) can be prepared from intermediate (XVI) by an amination reaction with an appropriate amine R1 in the presence of a base such as, for example, DIPEA.

[0109] In a particular embodiment, the present invention provides a compound of formula (IIIa) [ka] [During the ceremony, X is N or CH; R7 is OH and / or Cl; R8 is a halo. The present invention relates to the compound

[0110] In a further aspect, the present invention relates to the use of a compound of formula (IIIa) as an intermediate in the preparation of a compound of formula (I) above.

[0111] The compounds of the present invention have surprisingly been found to efficiently inhibit the P2X3 receptor, making said compounds effective in the treatment of respiratory diseases.

[0112] In certain embodiments, representative compounds of the present invention of formula (I) have surprisingly been found to efficiently and selectively inhibit P2X3 receptors, making them useful in treating respiratory diseases and avoiding adverse effects such as loss of taste response.

[0113] The compounds of formula (I) are selective P2X3 antagonists, wherein said selective P2X3 antagonists are P2X 2 / 3 It is at least 10-fold more selective for P2X3 homomeric receptor antagonism than heteromeric receptor antagonism.

[0114] In a preferred embodiment, the selective P2X3 antagonist is P2X 2 / 3 It is at least 30-fold more selective for P2X3 homomeric receptor antagonism over heteromeric receptor antagonism.

[0115] In a further preferred embodiment, the selective P2X3 antagonist is P2X 2 / 3 It is at least 50-fold more selective for P2X3 homomeric receptor antagonism over heteromeric receptor antagonism.

[0116] The present invention also provides pharmaceutical compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof, alone or in combination with one or more further active ingredients, in admixture with one or more pharmaceutically acceptable carriers or excipients.

[0117] In one embodiment, the present invention refers to a compound of formula (I) according to the present invention for use as a medicament.

[0118] In a further aspect, the present invention refers to the use of a compound of the present invention of formula (I) or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for the treatment of a disorder associated with the P2X3 receptor mechanism, preferably for the treatment of a respiratory disease.

[0119] Preferably, the present invention refers to a compound of formula (I) for use in the prevention and / or treatment of respiratory diseases, preferably cough, subacute or chronic cough, refractory cough, idiopathic chronic cough, cough after viral infection, iatrogenic cough, asthma, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and cough associated with respiratory diseases such as COPD, asthma and bronchospasm.

[0120] More preferably, the present invention refers to compounds of formula (I) for use in the prevention and / or treatment of chronic cough and cough associated with respiratory diseases such as COPD, asthma and bronchospasm.

[0121] The present invention also refers to a method for the prevention and / or treatment of disorders associated with P2X3 receptor mechanisms, which comprises administering to a patient in need of treatment a therapeutically effective amount of a compound of the present invention.

[0122] In another embodiment, the disorder that may be treated by the compounds of the invention is selected from the group consisting of cough, subacute or chronic cough, refractory cough, idiopathic chronic cough, cough after viral infection, iatrogenic cough, asthma, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and cough associated with respiratory diseases such as COPD, asthma and bronchospasm.

[0123] In a further preferred embodiment, the disorder is selected from cough and chronic cough.

[0124] The treatment method of the present invention involves administering to a patient in need of treatment a safe and effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof. As used herein, a "safe and effective amount," in reference to a compound of formula (I) or a pharmaceutically acceptable salt thereof or other pharmaceutically active substance, means an amount sufficient to treat the patient's condition but low enough to avoid serious side effects, although such an amount is routinely determined by one of ordinary skill in the art. The compound of formula (I) or a pharmaceutically acceptable salt thereof can be administered once or according to a dosing regimen in which various doses are administered at different time intervals over a predetermined period of time. Typical daily dosages can vary depending on the particular route of administration selected.

[0125] The present invention provides pharmaceutical compositions of compounds of formula (I) in admixture with one or more pharmaceutically acceptable carriers or excipients, for example, as described in Remington's Pharmaceutical Sciences Handbook, XVII Ed., Mack Pub., NY, USA.

[0126] Administration of the compounds of the present invention and pharmaceutical compositions thereof can be achieved, for example, orally, nasally, parenterally (subcutaneous, intravenous, intramuscular, intrasternal and infusion) and by inhalation, depending on the needs of the patient.

[0127] Preferably, the compounds of the present invention are administered orally and by inhalation.

[0128] A variety of solid oral dosage forms can be used to administer the compounds of the present invention, including solid forms such as tablets, gel capsules, capsules, caplets, granules, lozenges, and bulk powders. The compounds of the present invention can be administered alone or in combination with various pharmaceutically acceptable carriers, diluents (e.g., sucrose, mannitol, lactose, starch), and known excipients, including suspending agents, solubilizers, buffers, binders, disintegrants, preservatives, colorants, flavoring agents, lubricants, etc. Time-release capsules, tablets, and gels are also advantageous for administering the compounds of the present invention.

[0129] Preferably, the compounds of the present invention are administered in tablet form.

[0130] A variety of liquid oral dosage forms can also be used to administer the compounds of the present invention, including aqueous and non-aqueous solutions, emulsions, suspensions, syrups and elixirs.Such dosage forms also contain suitable known inert diluents such as water, and suitable known excipients such as preservatives, wetting agents, sweeteners, flavoring agents, and substances for emulsifying and / or suspending the compounds of the present invention.The compounds of the present invention can be administered in the form of an isotonic sterile solution, for example, intravenously.

[0131] For the treatment of diseases of the respiratory tract, the compounds according to the invention are preferably administered by inhalation.

[0132] Inhalable formulations include inhalable powders, propellant-containing metered dose aerosols or propellant-free inhalable formulations.

[0133] For administration as a dry powder, single or multi-dose inhalers known in the art can be utilized, in which case the powder can be filled into gelatin, plastic or other capsules, cartridges or blister packs, or can be present in a reservoir.

[0134] A diluent or carrier that is chemically inert to the compound of the present invention, such as lactose or any other additive suitable for improving the inhalation fraction, is added to the powdered compound of the present invention.

[0135] Inhalation aerosols containing a propellant gas such as a hydrofluoroalkane contain the compounds of the invention in solution or in dispersed form. Propellant-driven formulations may also contain other ingredients such as cosolvents, stabilizers and optionally other excipients.

[0136] Propellant-free inhalable formulations containing the compounds of the invention may be in the form of solutions or suspensions in aqueous, alcoholic or hydroalcoholic vehicles, which may be delivered by jet or ultrasonic nebulizers or soft mist nebulizers known in the art.

[0137] Preferably, the compounds of the present invention are administered orally.

[0138] The compounds of the invention may be administered as the sole active substance or in combination with other pharmaceutically active ingredients.

[0139] The dosage of the compounds of the present invention will depend on a variety of factors, including, inter alia, the particular disease being treated, the severity of the condition, the route of administration, and the like.

[0140] The present invention also relates to a device in the form of a single or multiple dose dry powder inhaler or a metered dose inhaler, which contains a pharmaceutical composition comprising a compound of formula (I) according to the invention.

[0141] Various aspects of the invention described herein are illustrated by the following examples, which are not meant to limit the invention in any way. The following examples illustrate the invention.

[0142] The examples of experimental implementations described herein serve to illustrate the invention, and the invention is not limited to the examples shown. [Example]

[0143] Preparation of Intermediates and Example Compounds Chemical names were assigned using Dotmatics software. In some cases, commonly used names of commercially available reagents were used instead of the names assigned by Dotmatics software.

[0144] All reagents for which the synthesis is not described in the experimental section are commercially available or are known compounds or can be prepared by methods known to those skilled in the art.

[0145] (R)-1-(2-(trifluoromethyl)pyrimidin-5-yl)ethanamine HCl, (R)-1-(6-methylpyridazin-3-yl)ethan-1-amine HCl were prepared according to the method described in WO 2016 / 091776.

[0146] Abbreviation-Meaning Et2O: diethyl ether; Et3N: triethylamine; TEA: triethylamine; DCC: N,N'-dicyclohexylcarbodiimide; PyBOP: (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate; DMF: dimethylformamide; EtOAc: ethyl acetate; RT: room temperature; THF: tetrahydrofuran; DCM: dichloromethane; MeOH: methyl alcohol; EtOH: ethyl alcohol; TFA: trifluoroacetic acid; LC-MS: liquid chromatography / mass spectrometry; HPLC: high performance liquid chromatography; MPLC: medium-pressure liquid chromatography; SFC: supercritical fluid chromatography; dppf: 1,1'-bis(diphenylphosphino)ferrocene; DIEA or DIPEA: N,N-diisopropylethylamine; MeCN: acetonitrile; MTBE: tert-butyl methyl ether; TBDMSCl: tert-butyl(chloro)dimethylsilane; DMSO: dimethyl sulfoxide; Boc2O: di-tert-butyl dicarbonate; UPLC: ultra-performance liquid chromatography.

[0147] General Experimental Details and Methods Analysis method Liquid chromatography-mass spectrometry Method 1 UPLC-MS was performed on a Waters Acquity I-Class equipped with a Waters Diode Array Detector connected to a Waters SQD2 single quadrupole mass spectrometer using a Waters HSS C18 column (1.8 μm, 100 × 2.1 mm) with an initial hold of 1.2 min at 5% acetonitrile / water (each mobile phase contained 0.1% formic acid), followed by a linear gradient from 5 to 100% within 3.5 min, followed by a hold at 100% for 1.5 min (F = 0.5 mL / min).

[0148] Method 2 UPLC-MS was performed on a Waters Acquity I-Class equipped with a Waters Diode Array Detector connected to a Waters SQD2 single quadrupole mass spectrometer using a Waters BEH Shield RP18 column (1.7 μm, 100 × 2.1 mm) with an initial hold of 1.2 min at 5% acetonitrile / water (each containing 10 mM ammonium bicarbonate), followed by a 5–100% linear gradient within 3.5 min, followed by a 1.5 min hold at 100% (F = 0.5 mL / min).

[0149] Method 3 UPLC-MS was performed on a Waters DAD + Waters SQD2, single quadrupole UPLC-MS spectrometer using an Acquity UPLC BEH Shield RP18 1.7 μm 100 × 2.1 mm (Plus guard cartridge). The column temperature was maintained at 5% acetonitrile / water (each containing 10 mM ammonium bicarbonate) for 0.4 min, followed by a linear gradient from 5 to 95% within 6.4 min, followed by a 1.2 min hold at 95% (F = 0.4 mL / min).

[0150] Method 4 UPLC-MS was performed on a Waters DAD + Waters SQD2, single quadrupole UPLC-MS spectrometer using an Acquity UPLC BEH Shield RP18 1.7 μm 100 × 2.1 mm (Plus guard cartridge) maintained at column temperature. The initial gradient was 5% acetonitrile (Far UV grade) with 0.1% (V / V) formic acid / 0.1% formic acid in water (high purity, PureLab Option unit) held for 0.4 min, followed by a linear gradient from 5 to 95% within 6.4 min, followed by a 1.2 min hold at 95% (F = 0.4 mL / min).

[0151] Method 4.1 Acquity UPLC-QDa mass spectrometer using a C18-reversed phase column (50 × 2.1 mm Acquity CSH with 1.7 μm particle size) maintained at 40 °C, eluting with A: 95 / 5 water / acetonitrile + 0.05% formic acid; B: 95 / 5 acetonitrile / water + 0.05% formic acid. gradient: [Table 8] Detection - MS, UV PDA MS ionization method - electrospray (positive / negative ion).

[0152] Method 4.2 Acquity UPLC-QDa mass spectrometer equipped with a C18 reversed-phase column (50 × 2.1 mm Acquity BEH with 1.7 μm particle size) maintained at 40 °C, eluting with A: 95 / 5 water / acetonitrile + 0.05% concentrated ammonia; B: 95 / 5 acetonitrile / water + 0.05% concentrated ammonia. gradient: [Table 9] Detection - MS, UV PDA MS ionization method - electrospray (positive / negative ion).

[0153] NMR 1 H nuclear magnetic resonance (NMR) spectroscopy was performed at near room temperature using Bruker or Varian instruments operating at 400 MHz with the solvents indicated unless otherwise noted. In all cases, the NMR data were consistent with the proposed structures. Characteristic chemical shifts (δ) are given in parts per million using conventional abbreviations for major peak designations, e.g., s, singlet; d, doublet; t, triplet; q, quartet; dd, doublet of doublets; dt, doublet of triplets; m, multiplet; and br, broad.

[0154] Preparative reversed-phase HPLC conditions Preparative HPLC purification was performed by reverse-phase HPLC using a Waters Fractionlynx preparative HPLC system (2525 pump, 2996 / 2998 UV / VIS detector, 2767 liquid handler) or an equivalent HPLC system, such as a Gilson Trilution UV-directed system. The Waters 2767 liquid handler acted as both the autosampler and fraction collector. The columns used for preparative purification of compounds were a 10 μm 19 × 150 mm Waters Sunfire OBD Phenomenex Luna Phenyl Hexyl or a Waters Xbridge Phenyl, 19 × 150, 5 μm column. Appropriate predefined gradients were selected based on the acidic or basic conditions, acetonitrile, and methanol solvent systems. The modifiers used under acidic / basic conditions were formic acid or trifluoroacetic acid (0.1% v / v) and ammonium bicarbonate (10 mM), respectively. The purification was controlled by Waters Fractionlynx software via monitoring from 210 to 400 nm, triggering a threshold collection value at 260 nm, and triggering the presence of the target molecular ion as observed under API conditions when using Fractionlynx. Collected fractions were analyzed by LCMS (Waters Acquity system equipped with a Waters SQD).

[0155] Chiral Supercritical Fluid Chromatography (SFC) Separation Protocol Diastereomeric separation of compounds was achieved by supercritical fluid chromatography (SFC) using a Waters Thar Prep100 preparative SFC system (P200 CO2 pump, 2545 modulating pump, 2998 UV / VIS detector, 2767 liquid handler equipped with a stacked injection module). The Waters 2767 liquid handler acted as both the autosampler and fraction collector. Appropriate isocratic methods were selected based on the solvent system: methanol, ethanol, or isopropanol, under either unmodified or basic conditions. The standard SFC method used was CO2 at 100 mL / min, 120 bar backpressure, and 40 °C column temperature. The modifier used under basic conditions was diethylamine (0.1% v / v). The modifier used under acidic conditions was formic acid (0.1% v / v) or trifluoroacetic acid (0.1% v / v). SFC purification was controlled by Waters Fractionlynx software via monitoring at 210-400 nm, typically operating at a threshold collection value of 260 nm. Collected fractions were analyzed by SFC (Waters / Thar SFC system equipped with a Waters SQD). Fractions containing the desired product were concentrated by vacuum centrifugation.

[0156] Supercritical fluid chromatography-mass spectrometry conditions Method 5 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux Cellulose-3 column with 15% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0157] Method 6 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux Cellulose-3 column with 20% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0158] Method 7 SFC-MS was performed isocratically using a Lux Cellulose-4 column on a Waters / Thar SFC system equipped with a Waters SQD, with 55% ethyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0159] Method 8 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux Cellulose-4 column with 20% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0160] Method 9 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux Cellulose-4 column with 30% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0161] Method 10 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux Cellulose-4 column with 50% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0162] Method 11 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux cellulose-4 column with 25% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0163] Method 12 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 15% ethyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0164] Method 13 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 25% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0165] Method 14 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 35% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0166] Method 15 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 55% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0167] Method 16 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 15% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0168] Method 17 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 20% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0169] Method 18 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC cellulose-C column with 15% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0170] Method 19 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC cellulose-C column with 15% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0171] Method 20 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC cellulose-C column with 25% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0172] Method 21 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC cellulose-SC column with 55% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0173] Method 22 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux Cellulose-3 column with 10% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0174] Method 23 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux Cellulose-3 column with 30% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0175] Method 24 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux cellulose-4 column with 20% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0176] Method 25 SFC-MS was performed isocratically using a Lux cellulose-4 column on a Waters / Thar SFC system equipped with a Waters SQD, with 40% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0177] Method 26 SFC-MS was performed isocratically using a Lux cellulose-4 column on a Waters / Thar SFC system equipped with a Waters SQD, with 55% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0178] Method 27 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a Lux Cellulose-4 column with 55% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0179] Method 28 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 20% ethyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0180] Method 29 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 25% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0181] method 30 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 55% methyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0182] Method 31 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC Amylose-C column with 30% isopropyl alcohol / CO2 (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40 °C.

[0183] Method 32 SFC-MS was performed isocratically on a Waters / Thar SFC system equipped with a Waters SQD using a YMC cellulose-C column with 40% isopropyl alcohol / CO (containing 0.1% diethylamine) at 5 mL / min, 120 bar back pressure, and a column temperature of 40°C.

[0184] Preparation of Intermediates and Example Compounds Intermediate 1 6-Bromopyrido[2,3-d]pyrimidin-4(3H)-one [ka] 2-Amino-5-bromonicotinic acid (35 g, 0.16 mol) and formamide (56 mcg, 1.41 mol) were heated at 140° C. for 20 hours. The mixture was cooled to 40° C. and water (100 mL) was added. The mixture was stirred for 30 minutes, after which more water (300 mL) was added. The reaction was filtered and the solid was washed with water (3×100 mL), 10% methanol-diethyl ether (3×100 mL), and diethyl ether (3×100 mL) to give the title compound (33.0 g, 90% yield) as a light brown solid. 1 H NMR (400MHz, DMSO): δ 12.78-12.77 (m, 1H), 9.09 (d, J=2.5Hz, 1H), 8.67 (d, J=2.5Hz, 1H), 8.41 (s, 1H). LCMS (Method 4): [MH + ]=226(2.38 minutes).

[0185] Intermediate 2 6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4(3H)-one [ka] Nitrogen was bubbled through a solution of 6-bromopyrido[2,3-d]pyrimidin-4(3H)-one (Intermediate 1) (1.0 g, 4.42 mmol), 4-fluorophenylboronic acid (929 mg, 6.64 mmol), and cesium carbonate (4.32 g, 13.27 mmol) in N,N-dimethylformamide (10 mL) and water (2 mL) for 5 minutes, after which tetrakis(triphenylphosphine)palladium(0) (664 mg, 0.57 mmol) was added. The resulting mixture was heated at 95 °C for 16 hours. After returning to room temperature, the reaction mixture was diluted with water (20 mL), filtered, and the solid was washed with diethyl ether to give the title compound as a beige solid (965 mg, 90%). LCMS (Method 4): [MH + ]=242(2.90 minutes).

[0186] The following compounds were synthesized according to the procedure described for the preparation of 6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4(3H)-one: [Table 10]

[0187] Example 1 6-(4-Fluorophenyl)-N-[1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl]pyrido[2,3-d]pyrimidin-4-amine [ka] To a solution of 6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4(3H)-one (Intermediate 2) (516 mg, 2.14 mmol) in N,N-dimethylformamide (15 mL) was added (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (1.17 g, 2.25 mmol) and diisopropylethylamine (1.7 mL, 9.63 mmol) in succession. The resulting mixture was heated at 45°C for 45 minutes, after which 1-(3-methyl-1,2,4-oxadiazol-5-yl)ethan-1-amine hydrochloride (600 mg, 3.0 mmol) was added, and heating was maintained at 45°C for 16 hours. After returning to room temperature, the mixture was diluted with ethyl acetate (25 mL) and water (70 mL). The organic phase was washed with brine (2 x 20 mL), passed through a hydrophobic frit and the solvent removed under reduced pressure. The residue was purified by preparative HPLC to give the title compound as a white solid (190 mg, 25%). 1 H NMR (400MHz, DMSO):δ 9.45(d, J=2.3Hz, 1H), 9.26-9.21(m, 2H), 8.69(s, 1H), 8.04-7.99(m, 2H), 7.49( dd, J=8.8, 8.8Hz, 2H), 5.88(d, J=6.8Hz, 1H), 2.38(s, 3H), 1.81(d, J=7.1Hz, 3H). LCMS (Method 3): [MH + ]=351(3.68 minutes).

[0188] Intermediate 20 6-(5-methylthiazol-2-yl)pyrido[2,3-d]pyrimidin-4(3H)-one [ka] Step 1: Preparation of 6-bromo-4-((2-(trimethylsilyl)ethoxy)methoxy)-pyrido[2,3-d]pyrimidine [ka] 6-Bromopyrido[2,3-d]pyrimidin-4(3H)-one (7.0 g, 30.97 mmol) was dissolved in N,N-dimethylformamide (260 mL) and the reaction mixture was cooled to 0 °C. Sodium hydride (60% dispersion in mineral oil, 1.49 g, 37.16 mmol) was added portionwise and the reaction mixture was stirred for 30 minutes. (2-Chloromethoxyethyl)trimethylsilane (8.2 mL, 46.45 mmol) was then added dropwise. The reaction was then stirred at 0 °C for 1 hour and then allowed to warm to room temperature. The reaction mixture was quenched with water (50 mL) and partitioned with ethyl acetate (50 mL). The phases were separated and the aqueous layer was washed with ethyl acetate (3 × 50 mL). The combined organic phases were dried over MgSO4, filtered, and concentrated under reduced pressure. The crude product was purified by column silica gel chromatography eluting with 0-70% ethyl acetate in dichloromethane to give the title compound as a white solid (6.0 g, 54%). 1 H NMR (400MHz, CDCl3): δ 9.01(d, J=2.4Hz, 1H), 8.74(d, J=2.4Hz, 1H), 8.40(s, 1H), 5.52(s, 2H), 3.66-3.62(m, 2H), 0.98-0.95(m, 2H), 0.02(s, 9H).

[0189] Step 2: Preparation of 5-methyl-2-(4-((2-(trimethylsilyl)ethoxy)-methoxy)pyrido[2,3-d]pyrimidin-6-yl)thiazole [ka] Nitrogen was bubbled through a suspension of 6-bromo-4-((2-(trimethylsilyl)ethoxy)methoxy)pyrido[2,3-d]pyrimidine (3500 mg, 9.82 mmol), bis(pinacolato)diboron (2993 mg, 11.79 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (401 mg, 0.49 mmol), and potassium acetate (1928 mg, 19.65 mmol) in 1,4-dioxane (80 mL) for 5 minutes. The reaction mixture was heated at 100 °C for 16 hours. The reaction was cooled to room temperature. To the resulting suspension was added water (16 mL), 2-bromo-5-methyl-1,3-thiazole (1836 mg, 10.3 mmol), cesium carbonate (6401 mg, 19.7 mmol), and an additional portion of [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (22 mg, 0.027 mmol). The reaction was heated at 100 °C for an additional 2 h. The reaction was cooled to room temperature and the solvent removed under reduced pressure. The residue was dissolved in dichloromethane and passed through a hydrophobic frit. The solvent was removed under reduced pressure, and the residue was purified by column chromatography on silica gel eluting with 30-50% ethyl acetate in dichloromethane. The resulting residue was triturated with diethyl ether to give the title compound as a pale yellow solid (2400 mg, 65%). LCMS (Method 4): [MH + ]=375(5.09 minutes).

[0190] Step 3: Preparation of 6-(5-methylthiazol-2-yl)pyrido[2,3-d]pyrimidin-4(3H)-one [ka] 5-Methyl-2-(4-((2-(trimethylsilyl)ethoxy)methoxy)pyrido[2,3-d]pyrimidin-6-yl)thiazole (1000 mg, 2.67 mmol) was dissolved in dichloromethane (15 mL) and trifluoroacetic acid (5 mL). The reaction mixture was stirred at room temperature for 5 hours. The solvent was removed under reduced pressure, and the residue was quenched with a saturated solution of sodium bicarbonate and water. The solid was filtered and dried under reduced pressure to give the title compound as a yellow solid (458 mg, 70%). LCMS (Method 4): [MH + ]=245(2.73 minutes).

[0191] The following compounds were synthesized according to the procedure described for the preparation of 6-(5-methylthiazol-2-yl)pyrido[2,3-d]pyrimidin-4(3H)-one. [Table 11]

[0192] Example 49 6-(5-Methylthiazol-2-yl)-N-[[3-(trifluoromethyl)-1,2,4-oxadiazol-5-yl]methyl]pyrido[2,3-d]pyrimidin-4-amine [ka] 6-(5-Methylthiazol-2-yl)pyrido[2,3-d]pyrimidin-4(3H)-one (60 mg, 0.25 mmol) and N,N-diisopropylethylamine (0.21 mL, 1.23 mmol) were suspended in toluene (2.5 mL). The reaction mixture was heated to 95°C, and phosphorus(V) oxychloride (0.027 mL, 0.30 mmol) was added. The reaction mixture was heated at 95°C for 2 hours and cooled to room temperature. The solvent was removed under reduced pressure. To the resulting residue was added [3-(trifluoromethyl)-1,2,4-oxadiazol-5-yl]methanamine hydrochloride (75 mg, 0.37 mmol), potassium carbonate (102 mg, 0.74 mmol), and N,N-dimethylformamide (2 mL). The reaction mixture was stirred at room temperature for 16 hours. The reaction mixture was diluted with ethyl acetate and filtered through a pad of Celite®. The solvent was removed under reduced pressure, and the resulting residue was purified by preparative HPLC to give the title compound as a pale yellow solid (3.1 mg, 3%). 1 H NMR (400MHz, DMSO):δ 9.90-9.86(m, 1H), 9.60(d, J=2.3Hz, 1H), 9.30(d, J=2.3Hz, 1H), 8.69(s, 1H), 7.83-7.81(m, 1H), 5.25(d, J=3.7Hz, 2H), 2.63(d, J=1.1Hz, 3H). LCMS (Method 4): [MH + ]=394.

[0193] The following compound was synthesized according to the procedure described for the preparation of 6-(5-methylthiazol-2-yl)-N-[[3-(trifluoromethyl)-1,2,4-oxadiazol-5-yl]methyl]pyrido[2,3-d]pyrimidin-4-amine. [Table 12]

[0194] Intermediate 24 6-(1-((6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-yl)amino)ethyl)pyridin-2(1H)-one [ka] Step 1: Preparation of 4-chloro-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidine [ka] To a stirred suspension of 6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4(3H)-one (1 g, 4.15 mmol) and N,N-diisopropylethylamine (3.6 mL, 20.7 mmol) in anhydrous toluene (20 mL) under a nitrogen atmosphere was added phosphorus oxychloride (0.5 mL, 5.39 mmol). The mixture was heated at 90 °C for 2 h, after which time analysis by LC-MS indicated conversion to the desired target. The solvent was removed in vacuo, and the resulting residue was washed with DCM (40 mL) and saturated aqueous NaHCO3 (10 mL). The layers were mixed thoroughly, then separated, and the aqueous phase was re-extracted with DCM (20 mL). The combined organic layers were washed with saturated aqueous NaHCO3 (10 mL), followed by water (10 mL), and dried by passing through a phase separator. The solvent was concentrated under reduced pressure to give a dark brown semi-solid which was used immediately in the next step without further purification (1.6 g, >100%).

[0195] Step 2: Preparation of 6-(1-((6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-yl)amino)ethyl)pyridin-2(1H)-one [ka] 4-Chloro-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidine (150 mg, 0.58 mmol), 6-(1-aminoethyl)pyridin-2(1H)-one·HBr (152 mg, 0.69 mmol), and N,N-diisopropylethylamine (0.40 mL, 2.31 mmol) in N,N-dimethylformamide (4 mL) were stirred at 40° C. for 4 days. The yellow precipitate was filtered off and purified by preparative HPLC to give the title compound as a colorless solid (61 mg, 29%). 1H NMR (400MHz, DMSO):δ 11.76-11.75(m, 1H), 9.42(d, J=2.5Hz, 1H), 9.22(d, J=2.5Hz, 1H), 8.83(d, J=6.8Hz, 1H), 8.65(s, 1H), 8.03(ddd, J=3.2, 5.4, 12.0Hz , 2H), 7.50(dd, J=8.8, 8.8Hz, 2H), 7.40(dd, J=8.0, 8.0Hz, 1H), 6.28-6.21(m, 2H), 5.38(dd, J=6.9, 6.9Hz, 1H), 1.65(d, J=7.1Hz, 3H). LCMS (Method 4): [MH + ]=362(2.85 minutes).

[0196] The following compounds were synthesized following a similar method as described for the preparation of 6-(1-((6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-yl)amino)ethyl)pyridin-2(1H)-one using the appropriate amine reagent: [Table 13-1] [Table 13-2] [Table 13-3]

[0197] Example 2 (R)-5-(1-((6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-yl)amino)ethyl)-2-(trifluoromethyl)pyridine 1-oxide [ka] 6-(4-Fluorophenyl)pyrido[2,3-d]pyrimidin-4(3H)-one (Intermediate 2) (23.5 g, 97.4 mmol, 1 equiv.) was suspended in SOCl2 (240 mL), and then DMF (2.5 mL) was added dropwise. The reaction mixture was heated at reflux until a clear solution formed. After the reaction was complete, the volatiles were removed under reduced pressure. The residue was taken up in EtOAc, then filtered and dried to give 4-chloro-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidine (23.6 g, 91.9 mmol, 94% yield). To a mixture of 4-chloro-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidine (100 mg, 0.385 mmol) and (R)-5-(1-aminoethyl)-2-(trifluoromethyl)pyridine 1-oxide hydrochloride (112 mg, 0.462 mmol) in DMF (volume: 2 mL) was added DIPEA (0.3 mL, 1.722 mmol). The mixture was stirred at 80 °C for 16 h. The reaction mixture was diluted with AcOEt and washed with half-saturated aqueous NaCl solution, followed by brine. The organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. Purification by DP chromatography (Biotage Isolera, 28 g NH cartridge, gradient elution 0–60% AcOEt in dichloromethane) followed by RP chromatography (Biotage Isolera, 30 g C18 cartridge, gradient elution 0–35% B in A. A: water / acetonitrile 95:5 + 0.05% HCOOH, B: acetonitrile / water 95:5 + 0.05% HCOOH) gave (R)-5-(1-((6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-yl)amino)ethyl)-2-(trifluoromethyl)pyridine 1-oxide as an off-white powder (122 mg, 0.284 mmol, 73.8% yield). LCMS (Method 4.1): 0.70 min, 430.1[M+H] + . 1H NMR (400MHz, DMSO-d6) δ ppm 9.36(d, J=2.19Hz, 1H), 9.14(d, J=2.19Hz, 1H), 8.88(d, J=6.80Hz, 1H), 8.61(s, 1H), 8.59(s, 1H), 7.97(dd, J=8.47, 5.38Hz, 2 H), 7.91(d, J=8.33Hz, 1H), 7.58(d, J=8.33Hz, 1H), 7.44(t, J=8.77Hz, 2H), 5.55(quin, J=6.96Hz, 1H), 1.66(d, J=7.02Hz, 3H).

[0198] The following example compounds were synthesized by applying similar methods. [Table 14]

[0199] Intermediate 3 - Method A 6-Bromo-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine [ka] To a solution of 6-bromopyrido[2,3-d]pyrimidin-4(3H)-one (Intermediate 1) (1.0 g, 4.42 mmol) and 1-(3-methyl-1,2,4-oxadiazol-5-yl)ethan-1-amine hydrochloride (996 mg, 4.98 mmol) in N,N-dimethylformamide (25 mL) was added N,N-diisopropylethylamine (3.9 mL, 22.12 mmol) and (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (2.76 g, 5.31 mmol). The mixture was heated at 40 °C for 5 h and stirred at room temperature for 2 days. The reaction was filtered, and the solid was washed with ethyl acetate (20 mL). The filtrate was washed with water (100 mL), and the aqueous layer was then extracted with ethyl acetate (3 × 40 mL). The organic phases were combined, washed with brine (50 mL), passed through a hydrophobic frit and the solvent removed under reduced pressure. The residue was purified by silica gel chromatography eluting with 0-10% dichloromethane. Fractions containing product were combined and triturated with diethyl ether to give the title compound as a white solid (766 mg, 46% yield). LCMS (Method 3): [MH + ]=335(2.94 minutes).

[0200] Intermediate 4 - Method B 6-Bromo-N-((6-methylpyridin-3-yl)methyl)pyrido[2,3-d]pyrimidin-4-amine [ka] A mixture of 6-bromo-4-chloropyrido[2,3-d]pyrimidine (1 g, 4.09 mmol), (6-methylpyridin-3-yl)methanamine (0.500 g, 4.09 mmol), and triethylamine (3 mL, 21.52 mmol) in 1,4-dioxane / DMF 5:1 (volume: 12 mL) was stirred at 100 °C for 16 h. The reaction mixture was concentrated under reduced pressure. Purification by column chromatography (Biotage Isolera, 55 g NH cartridge, gradient elution: 0 to 100% acetone in heptane) afforded 6-bromo-N-((6-methylpyridin-3-yl)methyl)pyrido[2,3-d]pyrimidin-4-amine as a pale yellow powder (1.21 g, 3.66 mmol, 90% yield). The expected product was collected in fractions and as an insoluble precipitate on top of the cartridge. LCMS (CSH basic method 2 min): 0.66 min, m / z 329.8 and 331.7 [M] + and [M+2] + .

[0201] The following intermediates were synthesized by reacting the appropriate substrate and amine intermediate and applying Method A or B (see table for specific method): [Table 15]

[0202] Example 6 N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)-6-(5-methylthiazol-2-yl)pyrido[2,3-d]-pyrimidin-4-amine [ka] Nitrogen was bubbled through a solution of 5-methyl-2-(tributylstannyl)thiazole (902 mg, 2.67 mmol), 6-bromo-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine (Intermediate 3) (2.75 mg, 0.82 mmol) in N,N-dimethylformamide (12 mL) for 5 minutes, after which tetrakis(triphenylphosphine)palladium(0) (142 mg, 0.123 mmol) was added. The resulting mixture was heated at 95° C. for 18 hours. After returning to room temperature, the reaction was diluted with water (60 mL) and brine (25 mL) and extracted with ethyl acetate (3×30 mL). The combined organic phase was filtered through a Celite® cartridge, washed with water (50 mL), dried over MgSO4, and filtered. The solvent was removed under reduced pressure. The residue was purified by silica gel chromatography eluting with 0-100% methanol in dichloromethane to give the title compound as an off-white solid (140 mg, 48% yield). LCMS (Method 3): [MH + ]=354(3.25 minutes).

[0203] The following compounds were synthesized following a similar method as described for the preparation of N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)-6-(5-methylthiazol-2-yl)pyrido[2,3-d]-pyrimidin-4-amine, starting from the intermediate shown in the table using the appropriate stannane reagent. [Table 16-1] [Table 16-2]

[0204] Intermediate 7 6-(5-chloropyridin-2-yl)pyrido[2,3-d]pyrimidin-4(3H)-one [ka] Nitrogen was bubbled through a solution of 6-bromopyrido[2,3-d]pyrimidin-4(3H)-one (Intermediate 1) (832 mg, 3.68 mmol) and 5-chloro-2-(tributylstannyl)thiazole (2.0 g, 4.97 mmol) in N,N-dimethylformamide (35 mL) for 5 minutes. Tetrakis(triphenylphosphine)palladium(0) (638 mg, 0.552 mmol) was added, and the mixture was heated at 95°C for 18 hours. After returning to room temperature, the reaction mixture was filtered, and the solid was washed with N,N-dimethylformamide (50 mL) and then with 10% methanol-dichloromethane solution (3 x 25 mL) to give the title compound as an off-white solid (470 mg, 49%). 1 H NMR (400MHz, DMSO):δ 12.72-12.72(m, 1H), 9.70-9.66(m, 1H), 9.15(s, 1H), 8.85(s, 1H), 8.42(s, 1H), 8.34(d, J=8.6Hz, 1H), 8.16(d, J=7.3Hz, 1H).

[0205] Example 11 (R)-6-(5-chloropyridin-2-yl)-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine [ka] To a solution of 6-(5-chloropyridin-2-yl)pyrido[2,3-d]pyrimidin-4(3H)-one (Intermediate 7) (80 mg, 0.31 mmol) in N,N-dimethylformamide (8 mL) was added (6-methylpyridazin-3-yl)methanamine dihydrochloride (69 mg, 0.35 mmol), N,N-diisopropylethylamine (0.27 mL, 1.55 mmol), and (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (1.93 mg, 0.37 mmol). The resulting mixture was heated at 60 °C for 48 hours. After returning to room temperature, the reaction mixture was diluted with dichloromethane (10 mL) and water (20 mL) and filtered. The solid was washed with water (5 mL) and dichloromethane (10 mL), and the filtrate was separated. The aqueous phase was further extracted with dichloromethane (2 x 15 mL). The organic phases were combined, passed through a hydrophobic frit and the solvent removed under reduced pressure. The residue was purified by preparative HPLC to give the title compound as an off-white solid (9.5 mg, 7%). 1 H NMR (400MHz, DMSO):δ 9.74(d, J=2.0Hz, 1H), 9.55(d, J=2.0Hz, 1H), 9.25(s, 2H), 9.21(d, J=6.1Hz, 1H), 8.88(d, J=2.0Hz, 1H), 8 .67(s, 1H), 8.32(d, J=8.6Hz, 1H), 8.25(dd, J=2.3, 8.6Hz, 1H), 5.77-5.71(m, 1H), 1.81(d, J=7.1Hz, 3H). LCMS (Method 4): [MH + ]=432(3.71 minutes).

[0206] The following compounds were synthesized following a similar method as described for the preparation of (R)-6-(5-chloropyridin-2-yl)-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine using the appropriate amine reagent. [Table 17]

[0207] Example 13 (R)-6-(4-fluorophenyl)-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine [ka] Nitrogen was bubbled through a mixture of (R)-6-bromo-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine (100 mg, 0.251 mmol), potassium carbonate (104 mg, 0.752 mmol), 4-fluorophenylboronic acid (39 mg, 0.276 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (18 mg, 0.0251 mmol) in 1,4-dioxane (2 mL) and water (0.5 mL) for 10 minutes. The reaction was heated at 110 °C for 20 minutes in a microwave reactor. After returning to room temperature, water (2 mL) was added and the mixture was extracted with ethyl acetate (2 × 20 mL). The combined organic phases were dried over MgSO4, filtered, and the solvent was removed under reduced pressure. The residue was purified by flash chromatography eluting with 0-20% methanol in dichloromethane, followed by preparative HPLC to give the title compound as an off-white solid (37 mg, 35%). 1 H NMR (400MHz, CDCl3):δ 9.21(d, J=2.4Hz, 1H), 8.56(d, J=2.3Hz, 1H), 7.51(d, J=1.0Hz, 1H), 7.44(d, J=8.5Hz, 1H), 7.36(d, J=8.7Hz, 1H), 5.04(d, J=4.8Hz, 2H) , 4.03-4.03(m, 2H), 3.97-3.96(m, 2H), 3.69(dd, J=5.1, 5.1Hz, 2H), 3.53(dd, J=5.1, 5.1Hz, 2H), 2.75(s, 3H), 2.54(s, 3H), 2.16(s, 3H). LCMS (Method 3): [MH + ]=476.0(3.06 minutes).

[0208] Compound 18 was obtained as a by-product in the preparation of the compound of Example 17.

[0209] Applying similar methods, starting from the appropriate intermediates, the following intermediates were prepared: [Table 18-1] [Table 18-2]

[0210] Example 19 N-((3,5-difluoropyridin-2-yl)methyl)-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-amine [ka] To a mixture of 6-bromo-4-chloropyrido[2,3-d]pyrimidine (100 mg, 0.409 mmol) and (3,5-difluoropyridin-2-yl)methanamine hydrochloride (73.9 mg, 0.409 mmol) in DMF (volume: 2 mL) was added DIPEA (0.15 mL, 0.861 mmol). The mixture was stirred at 80 °C for 6 h. After complete conversion of the starting material to 6-bromo-N-((3,5-difluoropyridin-2-yl)methyl)pyrido[2,3-d]pyrimidin-4-amine, water (1 mL) was added to the reaction mixture, followed by the addition of 4-fluorophenylboronic acid (86 mg, 0.614 mmol), potassium phosphate (174 mg, 0.818 mmol), and Pd(dppf)Cl CHCl (33.4 mg, 0.041 mmol). The mixture was stirred at 80 °C for 16 h. The mixture was cooled to room temperature, and then formic acid (0.154 mL, 4.09 mmol) was added. Purification by RP chromatography (Biotage Isolera, 30 g C18 cartridge, gradient elution 100:0 to 30:70 A / B, A: water / acetonitrile 95:5 + 0.1% HCOOH, B: acetonitrile:water 95:5 + 0.1% HCOOH in 15 CV) afforded N-((3,5-difluoropyridin-2-yl)methyl)-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-amine as an off-white powder (35.8 mg, 0.097 mmol, 23.83% yield). LCMS: 0.70 min, m / z 367.9[M+H]+, (Method 4.1):. 1 H NMR (400MHz, DMSO-d6) δ ppm 9.29-9.47(m, 1H), 9.20(t, 1H), 9.10(d, J=2.41Hz, 1H), 8.54-8.63(m, 1H), 8. 38-8.49(m, 1H), 7.81-8.04(m, 3H), 7.42(t, J=8.88Hz, 2H), 4.93-5.03(m, 2H).

[0211] Applying a similar method by starting from 6-bromo-4-chloropyrido[2,3-d]pyrimidine, using the appropriate amine and boronic acid or ester, the following examples were synthesized: [Table 19]

[0212] Intermediate 8 6-Bromopyrido[2,3-d]pyrimidine-2,4-diol [ka] 2-Amino-5-bromo-pyridine-3-carboxylic acid (3 g, 13.82 mmol) was triturated with urea (4.90 g, 81.59 mmol). The mixture was heated to the evaporation point of urea (280 °C) using a sand bath until solidification. After cooling, the resulting solid was dissolved in 50 mL of 2 N sodium hydroxide and then filtered while hot. 6 N HCl solution was added dropwise to the mixture until pH 8. The resulting precipitate was collected by filtration, washed with cold water, and dried under reduced pressure to give the title compound (3.0 g, 89.5%). LCMS (Method 4): [MH + ]=242.0(2.58 minutes).

[0213] Intermediate 9 6-Bromo-2,4-dichloropyrido[2,3-d]pyrimidine [ka] To a suspension of 6-bromopyrido[2,3-d]pyrimidine-2,4-diol (Intermediate 8) (500 mg, 2.07 mmol) in POCl3 (5 mL, 53.65 mmol) was added N,N-diisopropylethylamine (1.0 mL, 5.74 mmol). The mixture was heated at 120 °C for 18 h. The reaction mixture was poured onto ice, diluted with dichloromethane (15 mL), and stirred at room temperature for 1 h. The aqueous phase was extracted with dichloromethane (2 × 70 mL). The organic phases were combined, washed with a saturated aqueous solution of NaHCO3, dried over MgSO4, and filtered. The solvent was removed under reduced pressure to give the title compound as a red solid (470 mg, 82%). LCMS (Method 4): [MH + ]=278.0(4.30 minutes).

[0214] Intermediate 10 1-(4-(6-bromo-4-(((6-methylpyridazin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one [ka] Step 1: Preparation of 6-bromo-2-chloro-N-((6-methylpyridazin-3-yl)methyl)pyrido[2,3-d]pyrimidin-4-amine [ka] To a solution of 6-bromo-2,4-dichloropyrido[2,3-d]pyrimidine (Intermediate 9) (370 mg, 1.33 mmol) and 6-methylpyridazin-3-yl)methanamine dihydrochloride (312 mg, 1.59 mmol) in tert-butanol (10 mL) was added N,N-diisopropylethylamine (0.69 mL, 3.98 mmol). The reaction mixture was heated at 40° C. for 1 hour. The solvent was removed under reduced pressure, and the residue was used in the next step without further purification. LCMS (Method 3): [MH + ]=365.0(2.95 minutes).

[0215] Step 2: Preparation of 1-(4-(6-bromo-4-(((6-methylpyridazin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one (Intermediate 10) [ka] 6-Bromo-2-chloro-N-((6-methylpyridazin-3-yl)methyl)pyrido[2,3-d]pyrimidin-4-amine (485 mg, 1.33 mmol), 1-acetylpiperazine (340 mg, 2.65 mmol), and N,N-diisopropylethylamine (1.2 mL, 6.63 mmol) were dissolved in 1-butanol (10 mL). The reaction mixture was heated at 140° C. for 1 h. The reaction was cooled to room temperature, diluted with dichloromethane (20 mL), and washed with water (50 mL). The organic phase was dried over MgSO4, filtered, and the solvent was removed under reduced pressure to give the title compound as a red solid (350 mg, 58%). LCMS (Method 3): [MH + ]=457.0(2.86 minutes).

[0216] Examples 21 and 22 1-(4-(6-(4-fluorophenyl)-4-(((6-methylpyridazin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one (Example 21) and 1-(4-(4-(((6-methylpyridazin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one (Example 22) [ka] 1-(4-(6-Bromo-4-(((6-methylpyridazin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one (Intermediate 10) (50 mg, 0.11 mmol), potassium carbonate (45 mg, 0.33 mmol), 4-fluorophenylboronic acid (17 mg, 0.12 mmol), and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (8 mg, 0.01 mmol) were transferred into a microwave vial. 1,4-Dioxane (2 mL) and water (0.5 mL) were added, and the solution was degassed with nitrogen for 10 minutes. The reaction mixture was heated in a microwave reactor at 110° C. for 20 minutes. After returning to room temperature, water (2 mL) was added, and the mixture was extracted with ethyl acetate (2×20 mL). The organic phases were combined, dried over MgSO4, filtered, and the solvent was removed under reduced pressure. The residue was purified by preparative HPLC to give the title compound. Example 21 (18 mg, 35%) 1 H NMR (400 MHz, CDCl): δ 9.00(d, J=2.5Hz, 1H), 8.14(d, J=2.5Hz, 1H), 7.61-7.56(m, 3H), 7.47(d, J=8.5Hz, 1H), 7.40(d, J=8.5Hz, 1H), 7.20-7.15(m, 2H), 5.03(d, J=4.4Hz , 2H), 4.07(dd, J=3.7, 5.5Hz, 2H), 3.99(dd, J=3.4, 5.8Hz, 2H), 3.71(dd, J=5.3, 5.3Hz, 2H), 3.55(dd, J=5.2, 5.2Hz, 2H), 2.76(s, 3H), 2.17(s, 3H). LCMS (Method 3): [MH + ]=473.0(3.4 minutes). Example 22 (9.0 mg, 21%) 1H NMR (400MHz, CDCl3):δ 8.79(d, J=3.3Hz, 1H), 8.07(d, J=8.1Hz, 1H), 7.47-7.38(m, 3H), 7.07(dd, J=4.8, 8.1Hz, 1H), 5.00(d, J=3.8Hz, 2H), 4 .05(t, J=6.2Hz, 2H), 3.99(t, J=4.5Hz, 2H), 3.72-3.68(m, 2H), 3.54(dd, J=4.5, 4.5Hz, 2H), 2.75(s, 3H), 2.16(s, 3H). LCMS (Method 3): [MH + ]=379.0(2.36 minutes).

[0217] Example 23 1-(4-(4-(((6-methylpyridazin-3-yl)methyl)amino)-6-(5-methylthiazol-2-yl)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one [ka] Nitrogen gas was bubbled through a solution of 1-(4-(6-bromo-4-(((6-methylpyridazin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one (Intermediate 10) (50 mg, 0.109 mmol), 5-methyl-2-(tri-n-butylstannyl)thiazole (0.077 mL, 0.219 mmol), and tetrakis(triphenylphosphine)palladium(0) (19 mg, 0.0164 mmol) in N,N-dimethylformamide (2 mL) for 5 minutes. The mixture was heated at 80° C. for 18 hours. After returning to room temperature, the reaction mixture was diluted with methanol (5 mL) and loaded onto an SCX cartridge. The cartridge was washed with methanol, and the filtrate was collected when eluting with 7 M ammonia in methanol. The solvent was removed under reduced pressure and the residue was purified by preparative HPLC to give the title compound as an off-white solid (15 mg, 29%). 1H NMR (400MHz, CDCl3):δ 9.21(d, J=2.4Hz, 1H), 8.56(d, J=2.3Hz, 1H), 7.51(d, J=1.0Hz, 1H), 7.44(d, J=8.5Hz, 1H), 7.36(d, J=8.7Hz, 1H), 5.04(d, J=4.8Hz, 2H) , 4.03-4.03(m, 2H), 3.97-3.96(m, 2H), 3.69(dd, J=5.1, 5.1Hz, 2H), 3.53(dd, J=5.1, 5.1Hz, 2H), 2.75(s, 3H), 2.54(s, 3H), 2.16(s, 3H). LCMS (Method 3): [MH + ]=476.0(3.06 minutes).

[0218] The following compound was synthesized according to the procedure described for the preparation of 1-(4-(4-(((6-methylpyridazin-3-yl)methyl)amino)-6-(5-methylthiazol-2-yl)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one. [Table 20]

[0219] Intermediate 25 N-[1-(3-cyclopropyl-1,2,4-oxadiazol-5-yl)ethyl]-6-(4-fluorophenyl)pyrido-[2,3-d]pyrimidin-4-amine [ka] 6-(4-Fluorophenyl)pyrido[2,3-d]pyrimidin-4(3H)-one (200 mg, 0.83 mmol) was suspended in thionyl chloride (1.2 mL, 16.6 mmol) and DMF (0.6 μL, 0.008 mmol). The reaction mixture was heated at 95° C. for 16 hours and cooled to room temperature. The solvent was removed under reduced pressure. The resulting residue was suspended in dioxane (5.0 mL), followed by the addition of DIPEA (0.72 mL, 4.15 mmol) and [1-(3-cyclopropyl-1,2,4-oxadiazol-5-yl)ethyl]amine hydrochloride (236 mg, 1.24 mmol). The reaction mixture was heated at 95° C. for 3 hours and then cooled to room temperature. Water was added, and the resulting solid was filtered and dried under reduced pressure. The residue was purified by preparative HPLC to give the title compound as an off-white solid (257 mg, 82%) as a mixture of two enantiomers. 1 H NMR (400MHz, DMSO):δ 9.47-9.43(m, 1H), 9.19-9.16(m, 2H), 8.68(s, 1H), 8.05-7.98(m, 2H), 7.53-7.45(m, 2H), 5.86- 5.79(m, 1H), 2.20-2.12(m, 1H), 1.76(d, J=6.8Hz, 3H), 1.10(d, J=8.4Hz, 2H), 0.95-0.87(m, 2H). LCMS (Method 3): [MH + ]=377(4.09 minutes).

[0220] The following compound was synthesized according to the procedure described for the preparation of N-[1-(3-cyclopropyl-1,2,4-oxadiazol-5-yl)ethyl]-6-(4-fluorophenyl)-pyrido-[2,3-d]pyrimidin-4-amine. [Table 21-1] [Table 21-2] [Table 21-3] [Table 21-4] [Table 21-5]

[0221] Example 83 Single enantiomer 1 of 6-(5-fluoro-2-pyridyl)-N-[1-(5-methyl-1,3,4-thiadiazol-2-yl)ethyl]pyrido[2,3-d]pyrimidin-4-amine (Example 83) Example 84 Single enantiomer 2 of 6-(5-fluoro-2-pyridyl)-N-[1-(5-methyl-1,3,4-thiadiazol-2-yl)ethyl]pyrido[2,3-d]pyrimidin-4-amine [ka] 6-(5-Fluoropyridin-2-yl)pyrido[2,3-d]pyrimidin-4(3H)-one (200 mg, 0.64 mmol) was suspended in thionyl chloride (1.2 mL, 16.5 mmol) and DMF (0.001 mL). The reaction mixture was heated at 95°C for 22 hours. The reaction was cooled to room temperature, and the solvent was removed under reduced pressure. The resulting residue was diluted with saturated NaHCO3 solution, and the aqueous phase was extracted with ethyl acetate (2 x 50 mL). The combined organic phases were dried, and the solvent was removed under reduced pressure. The residue (145 mg) was dissolved in chloroform (1.0 mL), and 1-(5-methyl-1,3,4-thiadiazol-2-yl)ethan-1-amine (93 mg, 0.65 mmol) was added. The reaction mixture was heated at 70°C in a sealed tube under nitrogen for 18 hours. The resulting mixture was then cooled to room temperature. The reaction was diluted with cold water and stirred for 10 minutes. The solid was collected by filtration, after which ethyl acetate and water were added. The two phases were separated, and the aqueous phase was extracted with 5% methanol-ethyl acetate solution (2 x 50 mL). The combined organic phases were passed through phase separator paper, and the solvent was removed under reduced pressure. The residue was purified by achiral preparative HPLC, followed by chiral preparative SFC to give the title compound as an off-white solid. Example 83, Single Enantiomer 1: 24.7 mg, 13% 1 H NMR (400MHz, DMSO):δ 9.71(d, J=2.4Hz, 1H), 9.47(d, J=2.4Hz, 1H), 9.35(d, J=7.4Hz, 1H), 8.80(d, J=3.0Hz, 1H), 8.70(s, 1H) , 8.28(dd, J=4.3, 8.8Hz, 1H), 8.05-7.99(m, 1H), 6.02-5.97(m, 1H), 2.67(s, 3H), 1.82(d, J=7.0Hz, 3H). LCMS (Method 4): [MH + ]=368 (2.60 min). Chiral analysis (Method 30) (1.69 min). Example 84, Single Enantiomer 2: 27.3 mg, 14% 1 H NMR (400MHz, DMSO):δ 9.71(d, J=2.4Hz, 1H), 9.47(d, J=2.5Hz, 1H), 9.35(d, J=7.5Hz, 1H), 8.80(d, J=2.9Hz, 1H), 8.70(s, 1H) , 8.28(dd, J=4.3, 8.8Hz, 1H), 8.05-7.99(m, 1H), 6.02-5.97(m, 1H), 2.67(s, 3H), 1.82(d, J=7.0Hz, 3H). LCMS (Method 4): [MH + ]=368 (2.60 min). Chiral analysis (Method 30) (3.1 min).

[0222] Following a similar method as described for the preparation of the single enantiomers of 6-(5-fluoro-2-pyridyl)-N-[1-(5-methyl-1,3,4-thiadiazol-2-yl)ethyl]pyrido[2,3-d]pyrimidin-4-amine, the compounds shown in the table below were obtained as single isomers by chiral preparative SFC purification. [Table 22]

[0223] Example 91 6-(4-Fluorophenyl)-N-[(5-methyl-1,3,4-thiadiazol-2-yl)methyl]pyrido[2,3-d]pyrimidin-4-amine [ka] 6-(4-Fluorophenyl)pyrido[2,3-d]pyrimidin-4(3H)-one (90 mg, 0.37 mmol) and DIPEA (0.32 mL, 1.87 mmol) were suspended in toluene (3.5 mL). The reaction mixture was heated to 95°C, and phosphorus(V) oxychloride (0.042 mL, 0.45 mmol) was added. The reaction mixture was heated at 95°C for 2 hours and then cooled to room temperature. The solvent was removed under reduced pressure, and to the resulting residue was added (5-methyl-1,3,4-thiadiazol-2-yl)methanamine hydrochloride (93 mg, 0.56 mmol), DIPEA (0.32 mL, 1.87 mmol), and dioxane (3.5 mL). The reaction mixture was heated at 95°C for an additional 5 hours. The reaction mixture was diluted with water, and the solid was collected. The precipitate was suspended in DMSO and filtered. The solid was washed with water, then ethyl acetate and dried under vacuum to give the title compound as an off-white solid (31 mg, 24%). 1 H NMR (400MHz, DMSO):δ 9.62-9.56(m, 1H), 9.45(d, J=1.7Hz, 1H), 9.09(s, 1H), 8.77(s, 1H), 8.02 -7.96(m, 2H), 7.49(t, J=8.6Hz, 2H), 5.19(d, J=5.2Hz, 2H), 2.72(s, 3H). LCMS (Method 4): [MH + ]=353(2.78 minutes).

[0224] The following compound was synthesized according to the procedure described for the preparation of 6-(4-fluorophenyl)-N-[(5-methyl-1,3,4-thiadiazol-2-yl)methyl]pyrido[2,3-d]pyrimidin-4-amine. [Table 23]

[0225] Intermediate 11 6-chloro-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,4-d]pyrimidin-4-amine [ka] 6-Chloropyrido[3,4-d]pyrimidin-4(3H)-one (50 mg, 0.27 mmol), (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (158 mg, 0.30 mmol), and (6-methylpyridazin-3-yl)methanamine hydrochloride (59 mg, 0.30 mmol) were dissolved in N,N-dimethylformamide (1 mL) and N,N-diisopropylethylamine (1.2 mL, 7 mmol). The reaction mixture was heated at 50 °C for 16 h. After returning to room temperature, brine (10 mL) was added, and the mixture was extracted with ethyl acetate (3 × 15 mL). The combined organic phases were dried over MgSO4, filtered, and the solvent was removed under reduced pressure. The residue was purified by column silica gel chromatography eluting with 0–20% methanol in dichloromethane to give the title compound (50 mg, 65%). LCMS (Method 4): [MH + ]=288.0(2.33 minutes).

[0226] Following a similar method to that described for the preparation of 6-chloro-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,4-d]pyrimidin-4-amine (Intermediate 11), the following compounds were prepared: [Table 24]

[0227] Example 26 6-(4-Fluorophenyl)-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,4-d]pyrimidin-4-amine [ka] 6-Chloro-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,4-d]pyrimidin-4-amine (50 mg, 0.17 mmol), potassium carbonate (96 mg, 0.70 mmol), 4-fluorophenylboronic acid (73 mg, 0.52 mmol), and tetrakis(triphenylphosphine)palladium(0) (30 mg, 0.026 mmol) were added to a microwave vial. Dioxane (2 mL) and water (0.5 mL) were added, and the solution was degassed with nitrogen for 10 minutes. The reaction mixture was heated in a microwave reactor at 110 °C for 20 minutes. After returning to room temperature, water (2 mL) was added, and the mixture was extracted with ethyl acetate (2 × 15 mL). The combined organic phases were dried over MgSO4, filtered, and the solvent was removed under reduced pressure. The residue was purified by column silica gel chromatography eluting with 0-20% methanol in dichloromethane to give the title compound (9 mg, 15%). 1 H NMR (400MHz, DMSO):δ 9.57(t, J=5.1Hz, 1H), 9.32(s, 1H), 8.97(s, 1H), 8.71(s, 1H), 8.39(dd, J=5.6, 8.6Hz, 2H), 7.76(d, J =8.6Hz, 1H), 7.66(d, J=8.6Hz, 1H), 7.55(dd, J=8.8, 8.8Hz, 2H), 5.21(d, J=5.6Hz, 2H), 2.74(s, 3H). LCMS (Method 4): [MH + ]=347.0(3.18 minutes).

[0228] Following a similar method to that described for the preparation of 6-(4-fluorophenyl)-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,4-d]pyrimidin-4-amine, the following compound was prepared: [Table 25]

[0229] Example 28 N-[(6-methylpyridazin-3-yl)methyl]-6-(5-methylthiazol-2-yl)pyrido[3,4-d]pyrimidin-4-amine [ka] A mixture of 6-chloro-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,4-d]pyrimidin-4-amine (Intermediate 11) (100 mg, 0.35 mmol), 5-methyl-2-(tributylstannyl)thiazole (271 mg, 0.7 mmol), and potassium carbonate (96 mg, 0.70 mmol) in N,N-dimethylformamide (2 mL) was sparged with nitrogen for 5 minutes, followed by the addition of [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (57 mg, 0.07 mmol) and Cu(I)I (13 mg, 0.07 mmol). The resulting mixture was heated at 100 °C for 1 hour. The reaction was cooled, diluted with ethyl acetate (30 mL), and washed with water (10 mL). The organic phase was filtered through Celite®, and the solvent was removed under reduced pressure. The residue was purified by preparative HPLC to give the title compound as a brown solid (9 mg, 7%). 1 H NMR (400MHz, DMSO):δ 9.72(t, J=5.5Hz, 1H), 9.13(s, 1H), 8.99(s, 1H), 8.59-8.57(m, 1H), 7.75(s, 1H), 7 .62-7.58(m, 1H), 7.53-7.49(m, 1H), 5.05-5.01(m, 2H), 2.60(s, 3H), 2.55(s, 3H). LCMS (Method 4): [MH + ]=350(3.01 minutes).

[0230] Following a similar method to that described for the preparation of N-[(6-methylpyridazin-3-yl)methyl]-6-(5-methylthiazol-2-yl)pyrido[3,4-d]pyrimidin-4-amine, the following compound was prepared: [Table 26]

[0231] Intermediate 13 6-Bromo-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,2-d]pyrimidin-4-amine [ka] 6-Bromopyrido[3,2-d]pyrimidin-4(3H)-one (150 mg, 0.66 mmol), (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (380 mg, 0.73 mmol), and (6-methylpyridazin-3-yl)methanamine hydrochloride (143 mg, 0.73 mmol) were dissolved in N,N-dimethylformamide (1 mL) and N,N-diisopropylethylamine (2.9 mL, 16 mmol). The reaction mixture was heated at 50 °C for 6 h. After returning to room temperature, brine (10 mL) was added, and the reaction mixture was extracted with ethyl acetate (3 × 15 mL). The combined organic phases were dried over MgSO4, filtered, and the solvent was removed under reduced pressure. The residue was purified by column silica gel chromatography eluting with 0–20% methanol in dichloromethane to give the title compound as an off-white solid. LCMS (Method 4): [MH + ]=331.0(2.92 minutes).

[0232] Following a similar method to that described for the preparation of 6-bromo-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,2-d]pyrimidin-4-amine (Intermediate 13), the following compounds were prepared: [Table 27]

[0233] Example 31 6-(4-Fluorophenyl)-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,2-d]pyrimidin-4-amine [ka] 6-Bromo-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,2-d]pyrimidin-4-amine (Intermediate 13) (50 mg, 0.15 mmol), potassium carbonate (63 mg, 0.45 mmol), 4-fluorophenylboronic acid (23 mg, 0.16 mmol), and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (11 mg, 0.016 mmol) were added to a microwave vial. 1,4-Dioxane (2 mL) and water (0.5 mL) were added, and the solution was degassed with nitrogen for 10 minutes. The reaction mixture was heated in a microwave reactor at 110 °C for 20 minutes. After returning to room temperature, water (2 mL) was added, and the mixture was extracted with ethyl acetate (2 × 15 mL). The combined organic phases were dried over MgSO4, filtered, and the solvent was removed under reduced pressure. The residue was purified by column silica gel chromatography eluting with 0-20% methanol in dichloromethane to give the title compound as an off-white solid (22 mg, 42%). 1 H NMR (400MHz, CDCl3):δ 8.65(s, 1H), 8.22(t, J=5.9Hz, 1H), 8.19-8.08(m, 4H), 7.54(d, J=8.6Hz, 1H), 7 .33(d, J=8.6Hz, 1H), 7.23(t, J=6.9Hz, 2H), 5.19(d, J=6.1Hz, 2H), 2.73(s, 3H). LCMS (Method 4): [MH + ]=347.0(2.93 minutes).

[0234] Example 32 N-((6-methylpyridazin-3-yl)methyl)-6-(5-methylpyridin-2-yl)pyrido[3,2-d]-pyrimidin-4-amine [ka] Nitrogen was bubbled through a solution of 6-chloro-N-((6-methylpyridazin-3-yl)methyl)pyrido[3,2-d]pyrimidin-4-amine (70 mg, 0.21 mmol), 5-methyl-2-(tributylstannyl)pyridine (0.15 mL, 0.42 mmol), and tetrakis(triphenylphosphine)palladium(0) (37 mg, 0.032 mmol) in N,N-dimethylformamide (2 mL) for 5 minutes. The reaction mixture was heated at 80° C. for 18 hours. The crude product was cooled to room temperature, diluted with methanol, and loaded onto an SCX cartridge. The cartridge was washed with methanol, and the filtrate was collected when eluting with 7 M ammonia in methanol. The solvent was removed under reduced pressure, and the residue was purified by preparative HPLC to give the title compound (19 mg, 26% yield). 1 H NMR (400MHz, CDCl3):δ 8.84(d, J=8.8Hz, 1H), 8.67(s, 1H), 8.54(d, J=1.8Hz, 1H), 8.46(d, J=8.0Hz, 1H), 8.27(dd, J=5.3, 5.3Hz, 1H), 8.20(d, J=8.9Hz, 1H), 7.69(dd, J=1.9, 8.2Hz, 1H), 7.56(d, J=8.5Hz, 1H), 7.34(d, J=8.7Hz, 1H), 5.20(d, J=5.9Hz, 2H), 2.74(s, 3H), 2.43(s, 3H). LCMS (Method 3): [MH + ]=344.2(3.34 minutes).

[0235] The following compounds were synthesized according to a method similar to that used to prepare N-((6-methylpyridazin-3-yl)methyl)-6-(5-methylpyridin-2-yl)pyrido[3,2-d]-pyrimidin-4-amine: [Table 28]

[0236] Example 35 (R)-6-(5-methylpyridin-2-yl)-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[3,2-d]pyrimidin-4-amine [ka] To a solution of (R)-6-bromo-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[3,2-d]pyrimidin-4-amine (Intermediate 14) (210 mg, 0.53 mmol) in N,N-dimethylformamide (4.0 mL) was added potassium carbonate (145 mg, 1.05 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (86 mg, 0.10 mmol), and copper iodide (20 mg). The mixture was stirred for 10 minutes, after which 3-methyl-5-tributylstannyl thiazole (402 mg, 1.05 mmol) was added. The reaction was heated at 100 °C for 16 hours. After cooling to room temperature, water (10 mL) was added, and the reaction was extracted with dichloromethane (3 × 10 mL). The combined organic phase was filtered through a hydrophobic frit. The solvent was removed under reduced pressure, and the residue was purified by preparative HPLC to give the title compound as an off-white solid (7.1 mg, 33%). 1 H NMR (400MHz, DMSO):δ 9.25(s, 2H), 8.94(d, J=8.0Hz, 1H), 8.88(d, J=8.2Hz, 1H), 8.83(d, J=8.8Hz, 1H), 8.61(d, J=1.4Hz, 1H), 8.52(s, 1) H), 8.24(d, J=8.8Hz, 1H), 7.89(dd, J=1.7, 8.1Hz, 1H), 5.80(d, J=7.3Hz, 1H), 2.43(s, 3H), 1.83(d, J=7.2Hz, 3H). LCMS (Method 3): [M+H]=412.2 (4.60 min).

[0237] Example 36 (R)-6-(5-methylthiazol-2-yl)-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)-pyrido[3,2-d]pyrimidin-4-amine [ka] Nitrogen was bubbled through a solution of (R)-6-bromo-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[3,2-d]pyrimidin-4-amine (Intermediate 14) (100 mg, 0.25 mmol), potassium carbonate (69 mg, 0.501 mmol), 3-methyl-5-tributylstannyl thiazole (195 mg, 0.50 mmol), and copper iodide (9.5 mg, 0.05 mmol) in N,N-dimethylformamide (4.0 mL) for 5 minutes, after which [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (41 mg, 0.05 mmol) was added. The reaction was heated at 100 °C for 1 hour. After cooling to room temperature, water (10 mL) was added, and the reaction was extracted with dichloromethane (3 × 10 mL). The combined organic phases were filtered through a hydrophobic frit. The solvent was removed under reduced pressure. The residue was purified by preparative HPLC to give the title compound as an off-white solid (6.8 mg, 7%). 1 H NMR (400MHz, DMSO):δ 9.24(s, 2H), 8.59(d, J=8.0Hz, 1H), 8.53-8.48(m, 2H), 8.24(d, J=8.8Hz, 1H), 7.79(d, J=1.1Hz, 1H), 5.76-5.71(m, 1H), 2.58(s, 3H), 1.82(d, J=7.0Hz, 3H). LCMS (Method 3): [M+H]=418.2 (4.20 min).

[0238] Intermediate 15 6-(4-fluorophenyl)pyrido[3,2-d]pyrimidin-4(3H)-one [ka] Nitrogen was bubbled through a mixture of 6-bromopyrido[3,2-d]pyrimidin-4(3H)-one (286 mg, 1.27 mmol), potassium carbonate (252 mg, 3.80 mmol), and 4-fluoro(phenylboronic acid) (195 mg, 1.40 mmol) in 1,4-dioxane (5 mL) and water (0.5 mL) for 5 minutes, after which [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (93 mg, 0.127 mmol) was added. The reaction was sealed and heated in a microwave reactor at 110 °C for 30 minutes. After cooling to room temperature, water (5 mL) was added, and the reaction was extracted with ethyl acetate (3 × 5 mL). The combined organic phase was washed with brine (10 mL) and passed through a hydrophobic frit. The solvent was removed under reduced pressure. The residue was purified by column silica gel chromatography eluting with 0-15% methanol in dichloromethane to give the title compound as a red powder (294 mg, 96%). LCMS (Method 4): [M+H]=242.0 (3.15 min).

[0239] Example 37 (R)-6-(4-fluorophenyl)-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[3,2-d]pyrimidin-4-amine [ka] To a solution of 6-(4-fluorophenyl)pyrido[3,2-d]pyrimidin-4(3H)-one (Intermediate 15) (150 mg, 0.62 mmol) in N,N-dimethylformamide (2 mL) was added (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (356 mg, 0.68 mmol) and diisopropylethylamine (2.7 mL, 15.6 mmol) in succession. The resulting mixture was heated at 50 °C for 1 h, after which (R)-1-(2-(trifluoromethyl)pyrimidin-5-yl)ethan-1-amine hydrochloride (156 mg, 0.68 mmol) was added and heating was maintained at 50 °C for 2 h. After returning to room temperature, the mixture was diluted with ethyl acetate (50 mL) and water (10 mL). The organic phase was washed with brine (2 × 20 mL), passed through a hydrophobic frit, and the solvent was removed under reduced pressure. The residue was purified by preparative HPLC to give the title compound as an off-white solid (13 mg, 5%). 1 H NMR (400MHz, DMSO):δ 9.21(s, 2H), 8.53-8.44(m, 4H), 8.19(d, J=8.8Hz, 1H), 7.40(dd, J=8.8, 8.8Hz, 2H), 5.74(q, J=6.9Hz, 1H), 2.07(s, 1H), 1.81(d, J=7.0Hz, 3H). LCMS (Method 3): [M+H]=414.4 (4.96 min).

[0240] The following compound was synthesized according to a method similar to that described for the preparation of (R)-6-(4-fluorophenyl)-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[3,2-d]pyrimidin-4-amine: [Table 29]

[0241] Intermediate 16 6-Bromopteridin-4(3H)-one [ka] To a suspension of 3-amino-6-bromopyrazine-2-carboxamide (2 g, 9.22 mmol) in triethyl orthoformate (20 mL, 120.24 mmol) was added acetic anhydride (10 mL, 105.79 mmol). The reaction mixture was heated at 120° C. for 1 hour and at 90° C. for 2 days. After returning to room temperature, the reaction mixture was concentrated under reduced pressure. The residue was triturated in IPA, filtered, and dried to give the title compound as a brown solid (1.3 g, 62%). LCMS (Method 4): [MH + ]=227.0(1.81 minutes).

[0242] Intermediate 17 6-(4-fluorophenyl)pteridin-4(3H)-one [ka] 6-Bromopteridin-4(3H)-one (Intermediate 16) (300 mg, 1.32 mmol), potassium carbonate (548 mg, 3.96 mmol), 4-fluorophenylboronic acid (203 mg, 1.45 mmol), and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (97 mg, 0.132 mmol) were added to a microwave vial. Dioxane (5 mL) and water (0.5 mL) were added, and the solution was degassed with nitrogen for 10 minutes. The reaction mixture was heated in a microwave reactor at 110 °C for 35 minutes. After returning to room temperature, water (5 mL) was added, and the mixture was extracted with a mixture of CHCl3 / IPA (60:40) (3 × 20 mL). The combined organic phases were dried over MgSO4, filtered and the solvent removed under reduced pressure to give the title compound as a red solid (280 mg, 88%). LCMS (Method 4): [MH + ]=243.0(2.93 minutes).

[0243] Example 39 6-(4-Fluorophenyl)-N-((6-methylpyridazin-3-yl)methyl)pteridin-4-amine [ka] Step 1: Preparation of 4-chloro-6-(4-fluorophenyl)pteridine [ka] To a solution of 6-(4-fluorophenyl)pteridin-4(3H)-one (Intermediate 17) (280 mg, 1.16 mmol) in thionyl chloride (2.6 mL, 35.98 mmol) was added N,N-dimethylformamide (0.1 mL, 0.01 mmol), and the mixture was heated at reflux for 3 hours. After returning to room temperature, toluene (5 mL) was added, and the solvent was removed under reduced pressure. Two more additions of toluene and evaporation under reduced pressure gave the title compound, which was used in the next step without further purification.

[0244] Step 2: Preparation of 6-(4-fluorophenyl)-N-((6-methylpyridazin-3-yl)methyl)pteridin-4-amine 4-Chloro-6-(4-fluorophenyl)pteridine (120 mg, 0.460 mmol), 6-methylpyridazin-3-yl)methanamine dihydrochloride (81 mg, 0.506 mmol), and triethylamine (0.19 mL, 1.38 mmol) were dissolved in isopropanol (2.0 mL) and heated at 70 °C for 3 hours. The mixture was then cooled to room temperature and loaded onto an SCX cartridge. The cartridge was washed with methanol, and the filtrate was collected when extracted with 7 M ammonia-methanol. The solvent was removed under reduced pressure, and the residue was purified by preparative HPLC to give the title compound (8.6 mg, 7% yield). 1 H NMR (400MHz, CDCl3):δ 9.48(s, 1H), 8.81(s, 1H), 8.36(s, 1H), 8.16(dd, J=5.3, 8.6Hz, 2H), 7.53(d, J=8.6H z, 1H), 7.36(d, J=8.6Hz, 1H), 7.25-7.22(m, 2H), 5.18(d, J=5.6Hz, 2H), 2.75(s, 3H). LCMS (Method 4): [MH + ]=348.0(3.17 minutes).

[0245] Example 40 6-(4-Fluorophenyl)-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)pteridin-4-amine [ka] To a solution of 6-(4-fluorophenyl)pteridin-4(3H)-one (Intermediate 17) (40 mg, 0.165 mmol) in N,N-dimethylformamide (4 mL) was added (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (95 mg, 0.18 mmol), diisopropylethylamine (0.71 mL, 4.1 mmol), and 1-(3-methyl-1,2,4-oxadiazol-5-yl)ethan-1-amine hydrochloride (36 mg, 0.18 mmol) in succession. The resulting mixture was heated at 50°C for 2 h. After returning to room temperature, the mixture was diluted with water (10 mL) and extracted with ethyl acetate (3 x 10 mL). The combined organic phases were passed through a hydrophobic frit, and the solvent was removed under reduced pressure. The residue was purified by preparative HPLC to give the title compound as a yellow solid (113 mg, 12%). 1 H NMR (400MHz, DMSO):δ 9.81(s, 1H), 9.46(d, J=8.2Hz, 1H), 8.67-8.60(m, 3H), 7.47(dd, J=8.9, 8.9Hz, 2H), 5.94-5.88(m, 1H), 2.35(s, 3H), 1.81(d, J=7.2Hz, 3H). LCMS (Method 3): [MH + ]=352.2(3.93 minutes).

[0246] The following compound was synthesized following a similar method as described for the preparation of 6-(4-fluorophenyl)-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)pteridin-4-amine: [Table 30]

[0247] Chiral preparative SFC purification of the appropriate racemic mixture above gave the following compounds as single isomers as shown in the table below. [Table 31-1] [Table 31-2] [Table 31-3]

[0248] Pharmacological activity of the compounds of the present invention. In vitro electrophysiology assay of P2X3 Cells expressing P2X3 receptors were grown according to standard methods and maintained at 37°C in a 5% humidified CO2 atmosphere. Two days before the assay, cells were seeded into T175 flasks and detached from the flasks using TrypLE when grown to 80-90% confluence. Dissociated cells were cultured in serum-free medium at a cell density of 3 x 10 cells. 6Cells were resuspended at 1000 cells / ml and loaded into a Sophion Qube automated patch-clamp system. The extracellular assay buffer contained 145 mM NaCl, 4 mM KCl, 2 mM CaCl2, 1 mM MgCl2, 10 mM HEPES, and 10 mM glucose at pH 7.4. The intracellular assay solution contained 140 mM CsF, 10 mM NaCl, 10 mM EGTA, and 10 mM HEPES at pH 7.2. Agonist stock solutions were prepared in H2O and diluted with bath solution before use. All antagonists were prepared as 10 mM stock solutions in DMSO and diluted with bath solution before use. All experiments were performed in the whole-cell patch-clamp configuration at room temperature, with 384 individual cells simultaneously voltage-clamped at -60 mV on a Sophion Qube instrument. α,β-MeATP (800 nM) was applied, followed by agonist application to establish two baseline responses, which were then washed with extracellular assay buffer containing 0.5 U / ml apyrase. After the second agonist application, the antagonist was incubated for 10 minutes in the absence of α,β-MeATP. After antagonist preincubation, 800 nM α,β-MeATP and the antagonist were co-administered to determine the inhibitory effect of the antagonist. A concentration of antagonist was evaluated on a single cell, and different concentrations of antagonist were applied to other cells on 384 recording substrates. Control P2X3 current amplitudes were obtained from the peak current amplitude from the second agonist response before preincubation with the antagonist. The peak P2X3 current amplitude in the presence of antagonist was used to calculate the inhibitory effect at each concentration of antagonist according to the following formula: Percent inhibition of P2X3=(P2X3 control peak amplitude-P2X3 antagonist peak amplitude / P2X3 control peak amplitude)*100.

[0249] Concentration-response curves were generated from 10 different concentrations, with each concentration of antagonist tested on at least two individual cells. The concentration of antagonist that inhibited P2X3 currents by 50% (IC) was determined by fitting the data with the following equation: 50 ) was calculated. Y=a+[(ba) / (1+10^((logc-x)d)] where "a" is the minimum response, "b" is the maximum response, and "c" is the IC 50 and "d" is the hill gradient.

[0250] The results for individual compounds are provided in Table 8 below and show the range of activity. [Table 32-1] [Table 32-2] [Table 32-3]

[0251] P2X 2 / 3 In vitro electrophysiology assay Two modifications were made: 1) 10 μM ATP was used as the agonist; and 2) the P2X3 assay was used, in which the post-average current amplitude was measured 7 s after agonist application. 2 / 3 A similar assay protocol was used for the assay.

[0252] The results in Table 9 demonstrate that the compounds of the present invention are selective P2X3 antagonists. [Table 33]

Claims

1. Formula (Ia) 【Chemistry 1】 [During the ceremony, Z may optionally be (C １ -C ３ ) alkyl, halo, CN, (R Ａ R Ｂ ) NC(O)—; R １ is H; R ２ is heteroaryl (C １ -C ４ ) alkyl-, (C ３ -C ８ ) heterocycloalkyl-(C １ -C ６ ) alkyl, wherein any of said alkyl, heteroaryl is optionally selected from the group consisting of (C １ -C ３ ) Alkyl, halo, R Ａ O(C １ -C ４ ) alkylene-, (C １ -C ６ ) haloalkyl, R Ａ O-; R Ａ and R Ｂ is, in each occurrence, independently H or (C １ -C ４ ) alkyl-, or R Ａ and R Ｂ may optionally contain, together with the nitrogen atom to which they are attached, a further heteroatom which is a nitrogen atom, optionally R Ｃ (O)C-substituted 6-membered saturated heterocyclic monocyclic ring systems can be formed; R Ｃ (C １ -C ６ ) alkyl; J is H or (R Ａ R Ｂ )N- A compound represented by:

2. A compound selected from the group consisting of: 6-(4-fluorophenyl)-N-[1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl]pyrido[2,3-d]pyrimidin-4-amine, Single enantiomer 1 of 6-(4-fluorophenyl)-N-[1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl]pyrido[2,3-d]pyrimidin-4-amine, Single enantiomer 2 of 6-(4-fluorophenyl)-N-[1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl]pyrido[2,3-d]pyrimidin-4-amine; (R)-5-(1-((6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-yl)amino)ethyl)-2-(trifluoromethyl)pyridine 1-oxide; (R)-6-(4-fluorophenyl)-N-(1-(6-methylpyridazin-3-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine; (S)-2-((6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-yl)amino)-2-(6-methoxypyridin-3-yl)ethan-1-ol; 6-(4-fluorophenyl)-N-(2-morpholinoethyl)pyrido[2,3-d]pyrimidin-4-amine formate; (R)-6-(4-fluorophenyl)-N-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine; N-((6-methylpyridin-3-yl)methyl)-6-(p-tolyl)pyrido[2,3-d]pyrimidin-4-amine; 6-(4-fluorophenyl)-N-((6-methylpyridin-3-yl)methyl)pyrido[2,3-d]pyrimidin-4-amine; 2-(4-(((6-methylpyridin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-6-yl)benzonitrile; 2-(4-(((6-methylpyridin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-6-yl)benzamide; N-((3,5-difluoropyridin-2-yl)methyl)-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-amine; 6-(4-fluorophenyl)-N-((6-methylpyridazin-3-yl)methyl)pyrido[2,3-d]pyrimidin-4-amine; 1-(4-(6-(4-fluorophenyl)-4-(((6-methylpyridazin-3-yl)methyl)amino)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one; 1-(4-(4-(((6-methylpyridazin-3-yl)methyl)amino)-6-(5-methylpyridin-2-yl)pyrido[2,3-d]pyrimidin-2-yl)piperazin-1-yl)ethan-1-one; N-[(6-methylpyridazin-3-yl)methyl]-6-(5-methylthiazol-2-yl)pyrido[2,3-d]pyrimidin-4-amine, 2-((6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-yl)amino)-2-(5-methyl-1,2,4-oxadiazol-3-yl)ethan-1-ol, (R)-6-(4-fluorophenyl)-N-(1-(5-methyl-1,3,4-oxadiazol-2-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-(1-(5-methyl-1,3,4-thiadiazol-2-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine, (R)-6-(4-fluorophenyl)-N-(1-(5-methyl-1,2,4-oxadiazol-3-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-(2-(3-methyl-1,2,4-oxadiazol-5-yl)propan-2-yl)pyrido[2,3-d]pyrimidin-4-amine, N-(1-(3,5-difluoropyridin-2-yl)ethyl)-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-(2-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[(1R)-1-[6-(trifluoromethyl)pyridazin-3-yl]ethyl]pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[(5-methyl-1,3,4-oxadiazol-2-yl)methyl]pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[1-[3-(trifluoromethyl)-1,2,4-oxadiazol-5-yl]ethyl]pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[(3-methylisoxazol-5-yl)methyl]pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[(2-methylthiazol-4-yl)methyl]pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[(5-methyl-1,2,4-oxadiazol-3-yl)methyl]pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[(5-methyl-1,3,4-thiadiazol-2-yl)methyl]pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[(3-methyl-1,2,4-oxadiazol-5-yl)methyl]pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-[[3-(trifluoromethyl)-1,2,4-oxadiazol-5-yl]methyl]pyrido[2,3-d]pyrimidin-4-amine, 6-phenyl-N-[(1R)-1-[2-(trifluoromethyl)pyrimidin-5-yl]ethyl]pyrido[2,3-d]pyrimidin-4-amine, Single enantiomer 1 of 6-(4-fluorophenyl)-N-[1-[3-(trifluoromethyl)-1,2,4-oxadiazol-5-yl]ethyl]pyrido[2,3-d]pyrimidin-4-amine, Single enantiomer 1 of 6-(4-fluorophenyl)-N-(1-(5-methyl-1,3,4-thiadiazol-2-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine, 6-(4-fluorophenyl)-N-(1-(5-methyl-1,3,4-thiadiazol-2-yl)ethyl)pyrido[2,3-d]pyrimidin-4-amine single enantiomer 2, Single enantiomer 1 of N-[1-(3,5-difluoro-2-pyridyl)ethyl]-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-amine, a single enantiomer 2 of N-[1-(3,5-difluoro-2-pyridyl)ethyl]-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-amine, and N-[1-(3,5-difluoro-2-pyridyl)ethyl]-6-(4-fluorophenyl)pyrido[2,3-d]pyrimidin-4-amine.

3. 10. A pharmaceutical composition comprising a compound of claim 1 or 2, or a pharmaceutically acceptable salt thereof, alone or in combination with one or more other active ingredients, in admixture with one or more pharmaceutically acceptable carriers or excipients.

4. The pharmaceutical composition of claim 3 for oral administration.

5. 5. A pharmaceutical composition according to claim 3 or 4 for use as a medicament.

6. P2X ３ 5. A pharmaceutical composition according to claim 3 or 4 for use in the treatment of any disease in which the receptor is involved.

7. 5. The pharmaceutical composition according to claim 3 or 4 for use in the prevention and / or treatment of respiratory diseases including cough, subacute or chronic cough, refractory cough, idiopathic chronic cough, cough after viral infection, iatrogenic cough, asthma, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and cough associated with respiratory diseases such as COPD, asthma and bronchospasm.

8. 8. The pharmaceutical composition of claim 7 for use in the treatment of chronic cough.

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