Anti-proliferative agents for treating PAH

This invention relates to compounds of general Formula I in which A, R1, R2, R3 and R4 are as defined herein, and the pharmaceutically acceptable salts thereof; to pharmaceutical compositions comprising such compounds and salts; to methods of using such compounds, salts and compositions for treating pulmonary hypertension and related diseases, like pulmonary arterial hypertension; to methods of using such compounds, salts and compositions for treating abnormal cell growth, such as cancer; and to processes to make such compounds, salts and compositions.

FIELD OF INVENTION

Provided herein are 1,6-naphthyridinyl and pyrido[2,3-d]pyrimidinyl compounds useful for treating pulmonary hypertension and related diseases and useful for treating abnormal cell growth, such as cancer; processes to make such compounds; and methods of use of such compounds for treatment of pulmonary hypertension and related diseases, like pulmonary arterial hypertension, and for treatment of abnormal cell growth, such as cancer.

BACKGROUND OF THE INVENTION

Pulmonary hypertension (PH) has been previously classified as primary (idiopathic) or secondary. Recently, the World Health Organization (WHO) has classified pulmonary hypertension into five groups: Group 1: pulmonary arterial hypertension (PAH); Group 2: PH with left heart disease; Group 3: PH with lung disease and/or hypoxemia; Group 4: PH due to chronic thrombotic and/or embolic disease; and Group 5: miscellaneous conditions (e.g., sarcoidosis, histiocytosis X, lymphangiomatosis and compression of pulmonary vessels).

Pulmonary arterial hypertension is a serious, complex, progressive and life-threatening disease of the pulmonary vasculature, characterized by profound vasoconstriction and an abnormal proliferation of smooth muscle cells in the walls of the pulmonary arteries. Severe narrowing of the blood vessels in the lungs leads to very high pulmonary arterial pressures. These high pressures make it difficult for the heart to pump blood through the lungs to be oxygenated. Patients with PAH suffer from extreme shortness of breath as the heart struggles to pump against these high pressures. Patients with PAH typically develop significant increases in pulmonary vascular resistance (PVR) and sustained elevations in pulmonary artery pressure (PAP), which ultimately lead to right ventricular failure and death. Patients diagnosed with PAH have a poor prognosis and equally compromised quality of life, with a mean life expectancy of 2 to 5 years from the time of diagnosis if untreated.

There are currently 10 approved therapies for the treatment of PAH in the United States (US) and Europe. All of these therapies fall within one of 3 vasodilator classes including the prostacyclin analogs (epoprostenol, treprostinil, iloprost and selexipag), the endothelin receptor antagonists (ERA) (bosentan, ambrisentan, and macitentan), and agents affecting the Nitric Oxide signaling pathway including the soluble guanylate cyclase activator riociguat and the phosphodiesterase type-5 inhibitors sildenafil and tadalafil. These interventions address predominantly the endothelial and vascular hemodynamic dysfunction associated with the condition, and although it has been demonstrated that these therapies delay progression of the disease, morbidity and mortality remain high in this patient population. Despite the availability of these therapies, the five-year survival of patients with PAH remains as low at 57%. McGoon M D, Miller D P. REVEAL: A contemporary US pulmonary arterial hypertension registry.Eur Respir Rev.2012; 21:8-18.

The pathophysiology driving the vascular remodeling characteristic of PAH is multifactorial and includes abnormal vascular cell proliferation, reduced apoptosis, inflammation, in situ thrombosis and vasoconstriction. PAH is recognized to share many characteristics of a malignant phenotype including abnormal proliferation, formation of plexiform lesions in the proximity of pulmonary vasculature, altered mitochondrial metabolism and a switch to anaerobic metabolic pathways despite adequate oxygen supply. Two key cell types involved in progression towards PAH are Pulmonary Arterial Smooth Muscle Cells (PASMCs) and Pulmonary Artery Adventitial Fibroblasts (PAAFs). In WO2018/073687, inhibitors of cyclin-dependent kinases (CDKs), like palbociclib, are identified as being useful for the treatment of PAH, by assessing the effects on human and rat PASMCs and human PAAFs. However, there remains a need for treatment of PAH.

Moreover, CDKs and related serine/threonine protein kinases are important cellular enzymes that perform essential functions in regulating cell division and proliferation. The CDK catalytic units are activated by regulatory subunits known as cyclins. At least sixteen mammalian cyclins have been identified (Johnson D G, Walker C L. Cyclins and Cell Cycle Checkpoints. Annu. Rev. Pharmacol. Toxicol. (1999) 39:295 312). Additional functions of Cyclin/CDK heterodynes include regulation of transcription, DNA repair, differentiation and apoptosis (Morgan D O. Cyclin dependent kinases: engines, clocks, and microprocessors. Annu. Rev. Cell. Dev. Biol. (1997) 13:261 291).

CDK inhibitors have been demonstrated to be useful in treating cancer. Increased activity or temporally abnormal activation of CDKs has been shown to result in the development of human tumors, and human tumor development is commonly associated with alterations in either the CDK proteins themselves or their regulators (Cordon Cardo C. Mutations of cell cycle regulators: biological and clinical implications for human neoplasia. Am. J. Pathol. (1995) 147:545 560; Karp J E, Broder S. Molecular foundations of cancer: new targets for intervention. Nat. Med. (1995) 1:309 320; Hall M, Peters G. Genetic alterations of cyclins, cyclin dependent kinases, and CDK inhibitors in human cancer. Adv. Cancer Res. (1996) 68:67 108).

CDK4 and CDK6 are important regulators of cell cycle progression at the G1-S checkpoint, which are controlled by D-type cyclins and INK4 endogenous CDK inhibitors, such as p16INK4a (CDKN2A). Dysregulation of the cyclin D-CDK4/6-INK4-retinoblastoma (Rb) pathway has been reported to be associated with development of endocrine therapy resistance.

Mutations of CDK4 and CDK6 have been described in subgroups of melanoma and other tumors (Zuo L, et al., Germline mutations in the p16INK4a binding domain of CDK4 in familial melanoma.Nature Genet. (1996) 12, 97-99; Ortega S, et al. Cyclin D dependent kinases, INK4 inhibitors and cancer.Biochim. Biophys. Acta(2002) 1602:73 87; Smalley K S M et al. Identification of a novel subgroup of melanomas with KIT/cyclin dependent kinase 4 overexpression.Cancer Res(2008) 68: 5743 52). Amplifications of the regulatory subunits of CDKs and cyclins, and mutation, gene deletion, or transcriptional silencing of endogenous INK4 CDK inhibitors have also been reported as mechanism by which the pathway can be activated (Smalley KSM (2008)).

The development of CDK inhibitors has been reviewed in the literature. For example, see Sánchez-Martinez et al. Cyclin dependent kinase (CDK) inhibitors as anticancer drugs,Bioorg. Med. Chem. Lett. (2015) 25: 3420-3435 (and references cited therein). The use of CDK4/6 inhibitors in combination with endocrine therapy has demonstrated significant efficacy in the treatment of hormone receptor (HR)-positive, human epidermal growth factor 2 (HER2)-negative advanced or metastatic breast cancers, and CDK4/6 inhibitors, including palbociclib, ribociclib and abemaciclib, have been approved in combination with endocrine therapy in a first- or second-line setting.

Nevertheless, due to the potential for development of acquired resistance and other bypass mechanisms to CDK4/6 inhibitors, there remains a need to identify novel CDK4/6 inhibitors having an appropriate pharmacological profile, for example in terms of potency, selectivity, pharmacokinetics, and duration of action.

SUMMARY OF THE INVENTION

or a pharmaceutically acceptable salt thereof, wherein:

A is CH or N;

R2is C1-C4alkyl optionally substituted with 1, 2, or 3 substituents each independently selected from the group consisting of —OH, C1-C2alkoxy, and F;

R3is 4- to 8-membered heterocyclyl, C3-C8cycloalkyl, (4- to 8-membered heterocyclyl)-C1-C4alkyl-, or (C3-C8cycloalkyl)-C1-C4alkyl-,wherein each of the 4- to 8-membered heterocyclyl and the 4- to 8-membered heterocyclyl moiety in (4- to 8-membered heterocyclyl)-C1-C4alkyl- is optionally substituted with 1 or 2 R5,wherein each of the C3-C8cycloalkyl and the C3-C8cycloalkyl moiety in (C3-C8cycloalkyl)-C1-C4alkyl- is optionally substituted with 1 or 2 R5and further optionally substituted with 1-N(R6)2, andwherein each of the C1-C4alkyl moieties in (4- to 8-membered heterocyclyl)-C1-C4alkyl- and (C3-C8cycloalkyl)-C1-C4alkyl- is optionally substituted with 1, 2, or 3 R5; R4is a moiety having the structure of

each R6is independently selected from the group consisting of H and C1-C2alkyl;

each R7is independently H or C1-C2alkyl; and

The present invention also provides a pharmaceutical composition that includes a compound of Formula I, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient or carrier.

The present invention also provides a method for treating a disease or disorder in a subject, which method includes administering to the subject in need thereof a therapeutically effective amount of a compound of Formula I or a pharmaceutically acceptable salt thereof, wherein the disease or disorder is selected from the group consisting of pulmonary hypertension, pulmonary arterial hypertension, pulmonary hypertension with left heart disease, pulmonary hypertension with lung disease and/or hypoxemia, pulmonary hypertension due to chronic thrombotic and/or embolic disease, and diseases associated with pulmonary hypertension including sarcoidosis, histiocytosis X, lymphangiomatosis and compression of pulmonary vessels.

The present invention also provides a method for treating abnormal cell growth (such as cancer) in a subject, which method includes administering to the subject in need thereof a therapeutically effective amount of a compound of Formula I or a pharmaceutically acceptable salt thereof.

The present invention also provides use of a compound of Formula I, or a pharmaceutically acceptable salt thereof, for treating a disease or disorder, or in preparation a medicament for treating a disease or disorder, wherein the disease or disorder is selected from the group consisting of pulmonary hypertension, pulmonary arterial hypertension, pulmonary hypertension with left heart disease, pulmonary hypertension with lung disease and/or hypoxemia, pulmonary hypertension due to chronic thrombotic and/or embolic disease, and diseases associated with pulmonary hypertension including sarcoidosis, histiocytosis X, lymphangiomatosis and compression of pulmonary vessels.

The present invention also provides use of a compound of Formula I or a pharmaceutically acceptable salt thereof, for treating abnormal cell growth (such as cancer), or in preparation a medicament for treating abnormal cell growth (such as cancer).

The present invention also provides a method for inhibiting CDK (e.g. CDK4 and/or CDK6), which method including contacting the CDK with a compound of Formula I or a pharmaceutically acceptable salt thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention may be understood more readily by reference to the following Detailed Description and the Examples and schemes provided herein. It is to be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

It is to be understood that this invention is not limited to specific synthetic methods of making that may of course vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. In this specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings:

The term “about” refers to a relative term denoting an approximation of plus or minus 10% of the nominal value it refers, in one embodiment, to plus or minus 5%, in another embodiment, to plus or minus 2%. For the field of this disclosure, this level of approximation is appropriate unless the value is specifically stated to require a tighter range.

As used herein, the term “alkyl” is defined to include any acyclic, saturated aliphatic hydrocarbons including straight chains and branched chains. In some embodiments, the alkyl group 1 to 4 carbon atoms, 1 to 3 carbon atoms, 1 to 2 carbon atoms, or only one carbon atom. For example, the term “C1-6alkyl” refers to linear or branched aliphatic hydrocarbon chains of 1 to 6 carbon atoms, inclusive (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, or n-hexyl); the term “C1-4alkyl” refers to linear or branched aliphatic hydrocarbon chains of 1 to 4 carbon atoms, inclusive (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, or tert-butyl); the term “C1-2alkyl” refers to aliphatic hydrocarbon chains of 1 to 2 carbon atoms, inclusive; and the term “C1alkyl” refers to methyl and the term “C2alkyl” refers to ethyl. An alkyl group optionally can be substituted by one or more (e.g. 1 to 5) suitable substituents if and when so specified.

As used herein, the term “alkoxy” or “alkyloxy” refers to an —O-alkyl group. For example, the term “C1-C4alkoxy” or “C1-C4alkyloxy” refers to an —O—(C1-C4alkyl) group; and the term “C1-C2alkoxy” or “C1-C2alkyloxy” refers to an —O—(C1-C2alkyl) group. Examples of alkoxy include methoxy, ethoxy, propoxy (e.g., n-propoxy and isopropoxy), tert-butoxy, and the like. C1-C2alkoxy include methoxy and ethoxy. The alkoxy or alkyloxy group optionally can be substituted by 1 or more (e.g., 1 to 5) suitable substituents if and when so specified. As used herein, the term “cycloalkyl” refers to saturated or unsaturated, non-aromatic, monocyclic or polycyclic (such as bicyclic) hydrocarbon rings [e.g., monocyclics such as cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, cyclohexadienyl, cycloheptyl, cycloheptatrienyl, or bicyclics including spiro, fused, or bridged systems (such as bicyclo[1.1.1]pentanyl, bicyclo[2.2.1]heptanyl, bicyclo[3.1.0]hexanyl, or bicyclo[3.2.1]octanyl, etc.)]. In some embodiments the cycloalkyl may optionally contain one, two or more non-aromatic double or triple bonds in the ring structure and/or may optionally be substituted with one or more (e.g. one to three) oxo groups. In some embodiments, the bicycloalkyl group has 3 to 8 carbon atoms. For example, the term “C3-8cycloalkyl” refers to saturated or unsaturated, non-aromatic, monocyclic or polycyclic (such as bicyclic) hydrocarbon rings of 3 to 8 ring-forming carbon atoms (e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl cyclohexyl, bicyclo[3.1.0]hexanyl, bicyclo[1.1.1]pentanyl, or bicyclo[3.2.1]octanyl); and the term “Cm cycloalkyl” refers to saturated or unsaturated, non-aromatic, monocyclic or polycyclic (such as bicyclic) hydrocarbon rings of 3 to 6 ring-forming carbon atoms (e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, bicyclo[3.1.0]hexanyl, bicyclo[1.1.1]pentan-1-yl, or bicyclo[1.1.1]pentan-2-yl). For yet another example, the term “C3-4cycloalkyl” refers to saturated or unsaturated, non-aromatic, monocyclic hydrocarbon rings of 3 to 4 ring-forming carbon atoms (e.g. cyclopropyl or cyclobutyl). In some embodiments, a C3-8cycloalkyl group includes saturated monocyclic or polycyclic (such as bicyclic) hydrocarbon rings of 3 to 8 ring-forming carbon atoms and unsaturated monocyclic or polycyclic (such as bicyclic) hydrocarbon rings of 3 to 8 ring-forming carbon atoms with one ring double bond. In some embodiments, a C3-8cycloalkyl group includes saturated monocyclic or polycyclic (such as bicyclic) hydrocarbon rings of 3 to 8 ring-forming carbon atoms. The cycloalkyl group optionally can be substituted by 1 or more (e.g., 1 to 5) suitable substituents if and when so specified.

The term “heterocyclyl” means a saturated or partially unsaturated, nonaromatic ring system containing one or more (e.g. one, two, three, or four) ring-forming carbon atoms and one or more (e.g. one, two, three, or four) ring-forming heteroatoms each independently selected from the group consisting of oxygen, nitrogen and sulfur. The ring system of the heterocyclyl can be monocyclic or polycyclic (including 2 or more rings, for example, a bicyclic ring system), including spiro, fused, and/or bridged systems, wherein each of the individual ring within the ring system contains 1 or more ring-forming carbon atoms and 0, 1, or more (e.g. 0, 1, 2, or 3) ring-forming heteroatoms (each of which is independently selected from oxygen, nitrogen and sulfur). In some embodiments, a heterocyclyl group includes a saturated ring system containing one or more (e.g. one, two, three, or four) ring-forming carbon atoms and one or more (e.g. one, two, three, or four) ring-forming heteroatoms each independently selected from the group consisting of oxygen, nitrogen and sulfur. Some examples of “heterocyclyl” include lactones, lactams, cyclic ethers and cyclic amines. Certain nonlimiting examples of “heterocyclyl” include pyrrolidinonyl, 2,5-dihydro-1H-pyrrolyl, piperidinonyl, morpholinonyl, piperazinonyl, oxazolidinonyl, imidazolidinonyl, 1,3-oxazinan-2-onyl, tetrahydropyrimidin-2(1H)-onyl, epoxidyl, tetrahydrofuranyl, tetrahydropyranyl, dioxanyl, aziridinyl, azetidinyl, oxetanyl, pyrrolidinyl, oxazolidinyl, thiazolidinyl, piperidinyl, morpholinyl, piperazinyl, thiomorpholinyl, 1,3-oxazinanyl, 1,3-thiazinanyl, 2-azaspiro[3.3]heptanyl, 2-azabicyclo[2.1.1]hexanyl, 5-azabicyclo[2.1.1]hexanyl, 6-azabicyclo[3.1.1]heptanyl, 2-azabicyclo[2.2.1]heptanyl, 3-azabicyclo[3.1.1]heptanyl, 2-azabicyclo[3.1.1]heptanyl, 3-azabicyclo[3.1.0]hexanyl, 2-azabicyclo[3.1.0]hexanyl, 3-azabicyclo[3.2.1]octanyl, 8-azabicyclo[3.2.1]octanyl, 3-oxa-7-azabicyclo[3.3.1]nonanyl, 3-oxa-9-azabicyclo[3.3.1]nonanyl, 2-oxa-5-azabicyclo[2.2.1]heptanyl, 6-oxa-3-azabicyclo[3.1.1]heptanyl, 2-azaspiro[3.3]heptanyl and 2-oxa-6-azaspiro[3.3]heptanyl. In some embodiments, a ring-forming S atom in the heterocyclyl may be optionally substituted by one or two oxo groups if and when so specified, and/or a ring-forming carbon atom in the heterocyclyl may be optionally substituted by one oxo group if and when so specified. The heterocyclyl group optionally can be substituted by 1 or more (e.g., 1 to 5) suitable substituents if and when so specified.

As used herein, the term “halo” or “halogen” group is defined to include fluorine (F), chlorine (Cl), bromine (Br) or iodine (I).

As used herein, the term “fluoroalkyl” refers to an alkyl group having one or more halogen substituents (up to perfluoroalkyl, i.e., every hydrogen atom of the alkyl group has been replaced by a fluorine atom, for example, 1 to 5 hydrogen atoms of the alkyl group have been replaced by fluorine atoms). For example, as used herein, the term “C1-C4fluoroalkyl” means, a C1-C4alkyl, as defined herein, having one or more fluorine (F) substituents (up to perfluoroalkyl, i.e., every hydrogen atom of the C1-C4alkyl group has been replaced by a fluorine atom, for example, 1 to 5 hydrogen atoms of the alkyl group have been replaced by fluorine atoms; and the term “C1-C2fluoroalkyl” means, a C1-C2alkyl, as defined herein, having one or more fluorine (F) substituents (up to perfluoroalkyl, i.e., every hydrogen atom of the C1-C2alkyl group has been replaced by a fluorine atom). For another example, the term “C1fluoroalkyl” means methyl having one or more fluorine (F) substituents (up to perfluoroalkyl, i.e., every hydrogen atom of the methyl group has been replaced by a fluorine atom). Examples of C1-C4fluoroalkyl include CF3, CHF2, CH2F, CH2CF3, CH2CHF2, C2F5, CH2C2F5, CH2CH2CH2CF3, and the like; C1-C2fluoroalkyl includes CF3, CHF2, CH2F, CH2CF3, CH2CHF2, CH2CH2F; CHFCF3, CHFCHF2, CHFCH2F, CHFCH3, CF2CF3, CF2CHF2, CF2CH2F, and CF2CH3; and C1fluoroalkyl includes CF3, CHF2, and CH2F.

As used herein, the term “fluoroalkoxy” or “fluoroalkyloxy” refers to an —O-fluoroalkyl group. For example, the term “C1-C6fluoroalkoxy” or “C1-C6fluoroalkyloxy” refers to an —O—(C1-C6fluoroalkyl) group; the term “C1-C4fluoroalkoxy” or “C1-C4fluoroalkyloxy” refers to an —O—(C1-C4fluoroalkyl) group; and the term “C1-C2fluoroalkoxy” or “C1-C2fluoroalkyloxy” refers to an —O—(C1-C2fluoroalkyl) group. Examples of fluoroalkoxy include monofluoromethoxy (—OCH2F), difluoromethoxy (—OCHF2), trifluromethoxy (—OCF3), —OCH2CF3, —OC2F5, and the like.

A “substituted” atom or moiety indicates that any hydrogen on the designated atom or moiety can be replaced with a selection from the indicated substituent group (up to that every hydrogen atom on the designated atom or moiety is replaced with a selection from the indicated substituent group), provided that the normal valency of the designated atom or moiety is not exceeded, and that the substitution results in a stable compound. For example, if a methyl group (i.e., CH3) is substituted, then up to 3 hydrogen atoms on the carbon atom can be replaced with substituent groups. For another example, if a piperdin-4-yl is substituted with a substituent group, then any hydrogen atom on the ring-forming carbon atom or the ring-forming nitrogen atom can be replaced with the substituent group. Some examples of substituent groups for alkyl include halogen (e.g. F), OH, and —O—C1-C4alkyl (i.e. C1-C4alkoxy). Some examples of substituent groups for cycloalkyl or heterocyclyl include halogen, OH, —NH2, —NH(C1-C4alkyl), N(C1-C4alkyl)2, C1-C4alkyl (which further can be substituted with 0, 1 or more substituents each independently selected from halogen, OH, C1-C4alkoxy, and C1-C4haloalkoxy) and C1-C4alkoxy (which further can be substituted with 0, 1 or more substituents each independently selected from halogen, OH, C1-C4alkoxy and C1-C4fluoroalkoxy).

As used herein, the term “optionally substituted” means that substitution is optional and therefore includes both unsubstituted and substituted atoms and moieties.

As used herein, unless specified, the point of attachment of a substituent can be from any suitable position of the substituent. For example, piperidinyl can be piperidin-1-yl (attached through the N atom of the piperidinyl), piperidin-2-yl (attached through the C atom at the 2-position of the piperidinyl), piperidin-3-yl (attached through the C atom at the 3-position of the piperidinyl), or piperidin-4-yl (attached through the C atom at the 4-position of the piperidinyl). For another example, pyridinyl (or pyridyl) can be 2-pyridinyl (or pyridin-2-yl), 3-pyridinyl (or pyridin-3-yl), or 4-pyridinyl (or pyridin-4-yl).

As used herein, the term “n-membered” where n is an integer typically describes the number of ring-forming atoms in a ring moiety where the number of ring-forming atoms is n. For example, piperidinyl is an example of a 6-membered heterocyclyl ring and tetrahydropyranyl is an example of a 5-membered heterocyclyl group. Relatedly, the term “n- to m-membered” heterocyclyl (wherein the integer “n” describes the lower number of ring-forming atoms in the heterocyclyl and the integer “m” describes the upper number of ring-forming atoms) is specifically intended to include any of n-membered, (n+1)-membered, . . . and up to m-membered heterocyclyl group; for example, the term “4- to 8-membered heterocyclyl” is specifically intended to include any 4-, 5-, 6-, 7-, or 8-membered heterocyclyl group, inclusive.

At various places in the present specification, substituents of compounds of the invention are disclosed in groups or in ranges. It is specifically intended that the invention include each and every individual sub-combination of the members of such groups and ranges (including the end points). For example, the carbon atom content of alkyl and various other hydrocarbon-containing moieties can be indicated by a prefix designating the number of carbon atoms in the moiety, that is, the prefix Ciindicates a moiety of the integer “i” carbon atoms. For one example, C3alkyl indicates any alkyl with 3 carbon atoms, including propan-1-yl and propan-2-yl. For another example, the carbon atom content of alkyl and various other hydrocarbon-containing moieties is indicated by a prefix designating a lower and upper number of carbon atoms in the moiety, that is, the prefix indicates a moiety of the integer “i” to the integer “j” carbon atoms, inclusive. For one example, the term “C1-C6alkyl” is specifically intended to include C1alkyl (methyl), C2alkyl (ethyl), C3alkyl (i.e., propan-1-yl or propan-2-yl), C4alkyl (e.g. n-butyl, iso-butyl, or tert-butyl), C5alkyl (e.g. pentan-1-yl or 3-methylbutan-1-yl), and C6alkyl (e.g. hexan-1-yl or 3-methylpentan-1-yl). For another example, the term “C3-C6cycloalkyl” is specifically intended to include any C3cycloalkyl (cyclopropyl), C4cycloalkyl (e.g. cyclobutyl), C5cycloalkyl (e.g. cyclocpentyl), or C6cycloalkyl (e.g. cyclohexyl).

At various places in the present specification, the chemical terms such as alkyl, alkoxy, fluoroalkoxy (e.g. C1-C2alkyl, C1-C4alkyl, C1-C4fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy) can be used in combination with one or more other chemical terms, for example, “C1-C2alkoxy-C1-C2fluoroalkyl-”, “—C1-C4alkyl-(4- to 8-membered heterocyclyl)”, or “—C1-C4alkyl-(C3-C8cycloalkyl)”. In such situation, those skilled in the art would readily recognize the indicated point of attachment for the combination [e.g., the indicated point attachment for the “—C1-C4alkyl-(C3-C8cycloalkyl)” is through the “C1-C4alkyl” moiety] and that each moiety of the combination fulfills the normal valency rule [e.g. the “C1-C4alkyl” moiety of “—C1-C4alkyl-(C3-C8cycloalkyl)” is bivalent, i.e., linking to the “C3-C8cycloalkyl” moiety and attaching to the base molecular moiety through the indicated point of attachment; and for another example, the “C1-C2fluoroalkyl” moiety of the “C1-C2alkoxy-C1-C2fluoroalkyl-” is bivalent, linking to the “C1-C2alkoxy” moiety and attaching to the base molecular moiety through the indicated point of attachment].

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein R2is C1-C4alkyl optionally substituted with 1, 2, or 3 F and further optionally substituted with 1 OH or C1-C2alkoxy. In a further embodiment, R2is C1-C4alkyl optionally substituted with 1, 2, or 3 F and further optionally substituted with 1 C1-C2alkoxy. In a yet further embodiment, R2is C1-C2alkyl optionally substituted with 1, 2, or 3 F and further optionally substituted with 1 C1-C2alkoxy.

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein R2is C1-C2alkyl optionally substituted with 1, 2, or 3 F. In a further embodiment, R2is C1-C2alkyl. In a yet further embodiment, R2is methyl.

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein R3is 4- to 8-membered heterocyclyl or C3-C8cycloalkyl, wherein the 4- to 8-membered heterocyclyl is optionally substituted with 1 or 2 R5, and wherein the C3-C8cycloalkyl is optionally substituted with 1 or 2 R5and further optionally substituted with 1-N(R6)2. In a further embodiment, R3is 5- to 7-membered heterocyclyl or C3-C6cycloalkyl, wherein the 5- to 7-membered heterocyclyl is optionally substituted with 1 or 2 R5, and wherein the C3-C6cycloalkyl is optionally substituted with 1 or 2 R5and further optionally substituted with 1-N(R6)2.

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein R3is 4- to 8-membered heterocyclyl optionally substituted with 1 or 2 R5.

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein R3is C3-C8cycloalkyl optionally substituted with 1 or 2 R5and further optionally substituted with 1-N(R6)2. In a further embodiment, R3is C3-C8cycloalkyl. In a yet further embodiment, R3is cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or bicyclo[3.1.0]hexanyl.

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein:

A is CH or N;

R3is 5- to 7-membered heterocyclyl, C3-C6cycloalkyl, (5- to 7-membered heterocyclyl)-C1-C4alkyl-, or (C3-C6cycloalkyl)-C1-C4alkyl-,wherein each of the 5- to 7-membered heterocyclyl and the 5- to 7-membered heterocyclyl moiety in (5- to 7-membered heterocyclyl)-C1-C4alkyl- is optionally substituted with 1 R5,wherein each of the C3-C6cycloalkyl and the C3-C6cycloalkyl moiety in (C3-C6cycloalkyl)-C1-C4alkyl- is optionally substituted with 1 or 2 R5and further optionally substituted with 1-N(R6)2, andwherein each of the C1-C4alkyl moieties in (5- to 7-membered heterocyclyl)-C1-C4alkyl- and (C3-C6cycloalkyl)-C1-C4alkyl- is optionally substituted with 1, 2, or 3 R5; R4is a moiety having the structure of

each R6is independently selected from the group consisting of H and C1-C2alkyl; and

each R7is independently H or CH3, provided that no more than two R7are CH3.

An embodiment of the compound of Formula I of the present invention, or a pharmaceutically acceptable salt thereof, is a compound of Formula II:

or a pharmaceutically acceptable salt thereof (wherein A and R3are as defined in any of the embodiment described herein). In a further embodiment, the two substituents on the tetrahydropyran ring of Formula II are trans to each other (i.e., the two substituents on the tetrahydropyran ring are on the opposite sides of the tetrahydropyran ring).

An embodiment of the compound of Formula I or II, or a pharmaceutically acceptable salt thereof, is a compound of Formula III:

or a pharmaceutically acceptable salt thereof (wherein A and R3are as defined in any of the embodiment described herein).

An embodiment of the compound of Formula I, or a pharmaceutically acceptable salt thereof, of the invention, is a compound of Formula II:

or a pharmaceutically acceptable salt thereof, wherein:

A is CH or N;

In a further embodiment of the compound of Formula II, R3is 5- to 7-membered heterocyclyl optionally substituted with 1 R5(and R5is as defined in any of the embodiments described herein), and the two substituents on the tetrahydropyran ring of Formula II are trans to each other (i.e., the two substituents on the tetrahydropyran ring are on the opposite sides of the tetrahydropyran ring).

An embodiment of the compound of Formula I or II, or a pharmaceutically acceptable salt thereof, of the invention, is a compound of Formula III:

or a pharmaceutically acceptable salt thereof, wherein R3is 5- to 7-membered heterocyclyl optionally substituted with 1 R5(and R5is as defined in any of the embodiments described herein).

Another embodiment of the invention includes a compound of any one of Formulas I, II, and III, or a pharmaceutically acceptable salt thereof, wherein the 4- to 8-membered heterocyclyl or 5- to 7-membered heterocyclyl of R3comprises one ring-forming heteroatom selected from nitrogen or oxygen, and wherein the heterocyclyl is optionally substituted with 1 R5, and wherein R5is selected from the group consisting of F, OH, —CN, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl-, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-.

Another embodiment of the invention includes a compound of any one of Formulas I, II, and III, or a pharmaceutically acceptable salt thereof, wherein the 4- to 8-membered heterocyclyl or 5- to 7-membered heterocyclyl of R3is selected from the group consisting of 2-azaspiro[3.3]heptanyl, tetrahydrofuranyl, pyrrolidinyl, and piperidinyl, wherein each of the heterocyclyl selections is optionally substituted with 1 R5, and wherein R5is selected from the group consisting of F, OH, —CN, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl-, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-. One skilled in the art would appreciate that the 4- to 8-membered heterocyclyl or 5- to 7-membered heterocyclyl of R3can be attached to the base molecular moiety through a ring-forming carbon or ring-forming nitrogen atom of the heterocyclyl. In addition, one skilled in the art would appreciate that a R5substituent can attach to a ring-forming carbon or ring-forming nitrogen atom of the heterocyclyl.

Another embodiment of the invention includes a compound of any one of Formula I, II, or III, or a pharmaceutically acceptable salt thereof, wherein the 4- to 8-membered heterocyclyl or 5- to 7-membered heterocyclyl of R3is selected from the group consisting of 2-azaspiro[3.3]heptan-6-yl, pyrrolidin-3-yl, piperidin-4-yl, and tetrahydrofuran-3-yl, each is optionally substituted with 1 R5, and R5is selected from the group consisting of F, OH, —CN, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl-, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-. In a yet further embodiment, the 4- to 8-membered heterocyclyl or 5- to 7-membered heterocyclyl of R3is selected from the group consisting of 2-azaspiro[3.3]heptan-6-yl, pyrrolidin-3-yl, 1-methylpyrrolidin-3-yl, 2-(2-methoxyethyl)-2-azaspiro[3.3]heptan-6-yl, 2-(2,2-difluoroethyl)-2-azaspiro[3.3]heptan-6-yl, and piperidin-4-yl.

Another embodiment of the invention includes a compound of any one of Formula I, II, or III, or a pharmaceutically acceptable salt thereof, wherein R3is 2-azaspiro[3.3]heptan-6-yl optionally substituted with 1 R5that is selected from the group consisting of C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy-C1-C2alkyl-, and C1-C2fluoroalkoxy-C1-C2alkyl-.

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein A is N, and R3is 4- to 8-membered heterocyclyl optionally substituted with 1 R5(and R5is as defined in any of the embodiments described herein). In a further embodiment, the compound or a pharmaceutically acceptable salt thereof is a compound of Formula II or III, wherein R3is 5- to 7-membered heterocyclyl optionally substituted with 1 R5.

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein A is CH, and R3is 4- to 8-membered heterocyclyl optionally substituted with 1 R5(and R5is as defined in any of the embodiments described herein). In a further embodiment, the compound or a pharmaceutically acceptable salt thereof is a compound of Formula II or III, wherein R3is 5- to 7-membered heterocyclyl optionally substituted with 1 R5(and R5is as defined in any of the embodiments described herein).

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein R3is C3-C6cycloalkyl optionally substituted with 1 or 2 R5and further optionally substituted with 1-N(R6)2, wherein each of R5and R6is as defined in any of the embodiments described herein. In a further embodiment, R3is selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexanyl, and bicyclo[3.1.0]hexanyl, wherein each of the cycloalkyl selections is optionally substituted with 1 or 2 R5, and further optionally substituted with 1-N(R6)2; each R5is independently selected from the group consisting of F, OH, —CN, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-; and each R6is independently selected from the group consisting of H and C1-C2alkyl.

An embodiment of the invention is a compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein R3is cyclobutyl or cyclopentyl, each optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F, OH, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-.

An embodiment of the compound of Formula I, or a pharmaceutically acceptable salt thereof, of the invention, is a compound of Formula II:

or a pharmaceutically acceptable salt thereof, wherein:

A is CH or N;

each R6is independently selected from the group consisting of H and C1-C2alkyl.

In a further embodiment of the compound of Formula II wherein R3is C3-C6cycloalkyl optionally substituted with 1 or 2 R5and further optionally substituted with 1 —N(R6)2(wherein each of R5and R6is as defined in any of the embodiments described herein), and the two substituents on the tetrahydropyran ring of Formula II are trans to each other (i.e., the two substituents on the tetrahydropyran ring are on the opposite side of the tetrahydropyran ring).

An embodiment of the compound of Formula I or II, or a pharmaceutically acceptable salt thereof, of the invention, is a compound of Formula III:

or a pharmaceutically acceptable salt thereof, wherein R3is C3-C6cycloalkyl optionally substituted with 1 or 2 R5and further optionally substituted with 1 —N(R6)2(wherein each of R5and R6is as defined in any of the embodiments described herein).

An embodiment of the invention includes a compound of any one of Formulas I, II, or III, wherein the C3-C8cycloalkyl or C3-C6cycloalkyl of R3is selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexanyl, and bicyclo[3.1.0]hexanyl, wherein each of the cycloalkyl selections is optionally substituted with 1 or 2 R5, and further optionally substituted with 1 —N(R6)2; each R5is independently selected from the group consisting of F, OH, —CN, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-; and each R6is independently selected from the group consisting of H and C1-C2alkyl.

An embodiment of the invention includes a compound of any one of Formulas I, II, and III, wherein the C3-C8cycloalkyl or C3-C6cycloalkyl of R3is selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and bicyclo[3.1.0]hexanyl, wherein each of the cycloalkyl selections is optionally substituted with 1 or 2 R5and further optionally substituted with 1 —N(R6)2; each R5is independently selected from the group consisting of F, OH, —CN, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-; and each R6is independently selected from the group consisting of H and C1-C2alkyl. In a further embodiment, the C3-C8cycloalkyl or C3-C6cycloalkyl of R3is selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and bicyclo[3.1.0]hexan-2-yl, wherein each of the cycloalkyl selections is optionally substituted with 1 or 2 R5and further optionally substituted with 1 —N(R6)2. In a yet further embodiment, each R5is independently selected from the group consisting of F, OH, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-. In a still further embodiment, each R5is independently selected from the group consisting of F, OH, C1-C2alkyl, C1-C2fluoroalkyl, and C1-C2alkoxy-C1-C2alkyl-. In a yet still further embodiment, each R5is independently selected from the group consisting of F, OH, CH3, and CH2CH3; and each R6is independently selected from the group consisting of H and CH3.

An embodiment of the invention includes a compound of any one of Formulas I, II, or III, or a pharmaceutically acceptable salt thereof, wherein R3is bicyclo[3.1.0]hexan-2-yl, optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F, OH, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-.

An embodiment of the invention includes a compound of any one of Formulas I, II, or III, or a pharmaceutically acceptable salt thereof, wherein the C3-C8cycloalkyl or C3-C6cycloalkyl of R3is cyclohexyl (also known as cyclohexanyl) optionally substituted with 1 or 2 R5and further optionally substituted with 1 —N(R6)2(wherein each of R5and R6is as defined in any of the embodiments described herein). In a further embodiment, R3is cyclohexyl substituted with 1-N(R6)2(wherein each of R6is as defined in any of the embodiments described herein). In a yet further embodiment, each R6is independently selected from the group consisting of H and CH3.

An embodiment of the invention includes a compound of any one of Formulas I, II, or III, or a pharmaceutically acceptable salt thereof, wherein the C3-C8cycloalkyl or C3-C6cycloalkyl of R3is cyclobutyl optionally substituted with 1 or 2 R5(wherein each of R5is as defined in any of the embodiments described herein). In a further embodiment, each R5is independently selected from the group consisting of F, OH, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-.

An embodiment of the invention includes a compound of any one of Formulas I, II, or III, or a pharmaceutically acceptable salt thereof, wherein the C3-C8cycloalkyl or C3-C6cycloalkyl of R3is cyclopentyl optionally substituted with 1 or 2 R5and further optionally substituted with 1 —N(R6)2(wherein each of R5and R6is as defined in any of the embodiments described herein). In a further embodiment, R3is cyclopentyl optionally substituted with 1 or 2 R5(wherein each of R5is as defined in any of the embodiments described herein). In a yet further embodiment, R3is cyclopentyl optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F, OH, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-. In a still further embodiment, R3is cyclopentyl.

An embodiment of the invention includes a compound of any one of Formulas I, II, or III, or a pharmaceutically acceptable salt thereof, wherein A is CH (and the other variables, such as R1, R2, R3, R4, when present, are as defined in any of the embodiments described herein).

An embodiment of the invention includes a compound of any one of Formulas I, II, or III, or a pharmaceutically acceptable salt thereof, wherein A is N (and the other variables, such as R1, R2, R3, R4, when present, are as defined in any of the embodiments described herein).

An embodiment of the invention is a compound of Formula I, II, or III, wherein R3is (5- to 7-membered heterocyclyl)-C1-C4alkyl- or (C3-C6cycloalkyl)-C1-C4alkyl-, wherein each of the 5- to 7-membered heterocyclyl moiety in (5- to 7-membered heterocyclyl)-C1-C4alkyl- is optionally substituted with 1 or 2 R5, and wherein the C3-C6cycloalkyl moiety in (C3-C6cycloalkyl)-C1-C4alkyl- is optionally substituted with 1 or 2 R5and further optionally substituted with 1 —N(R6)2(wherein each of R5and R6is as defined in any of the embodiments described herein). Some examples of the 5- to 7-membered heterocyclyl moiety include 2-azaspiro[3.3]heptanyl, tetrahydrofuranyl, pyrrolidinyl, or piperidinyl, each of which is optionally substituted with 1 R5, and R5is selected from the group consisting of F, OH, —CN, C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl-, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-. Some examples of the C3-C6cycloalkyl moiety include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexanyl, or bicyclo[3.1.0]hexanyl, each of which is optionally substituted with 1 or 2 R5and further optionally substituted with 1 —N(R6)2; wherein each R5is independently selected from the group consisting of F, OH, CH3, and CH2CH3; and each R6is independently selected from H and CH3.

An embodiment of the invention includes a compound of Formula II or III, or a pharmaceutically acceptable salt thereof, wherein A is N; R3is cyclobutyl, cyclopentyl, or bicyclo[3.1.0]hexanyl, each is optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F, OH, CH3, or CH2CH3. In a further embodiment, R3is cyclobutyl, cyclopentyl, or bicyclo[3.1.0]hexan-2-yl, each is optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F and CH3. In a yet further embodiment, the compound or a pharmaceutically acceptable salt thereof is a compound of Formula III or a pharmaceutically acceptable salt thereof.

An embodiment of the invention includes a compound of Formula II or III, or a pharmaceutically acceptable salt thereof, wherein A is CH; R3is cyclobutyl, cyclopentyl, or bicyclo[3.1.0]hexanyl, each is optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F, OH, CH3, or CH2CH3. In a further embodiment, R3is cyclobutyl, cyclopentyl, or bicyclo[3.1.0]hexan-2-yl, each is optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F and CH3. In a yet further embodiment, the compound or a pharmaceutically acceptable salt thereof is a compound of Formula III or a pharmaceutically acceptable salt thereof.

An embodiment of the invention includes a compound of Formula II or III, or a pharmaceutically acceptable salt thereof, wherein A is N; R3is cyclopentyl optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F, OH, CH3, or CH2CH3. In a further embodiment, R3is cyclopentyl optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F and CH3. In a yet further embodiment, the compound or a pharmaceutically acceptable salt thereof is a compound of Formula III or a pharmaceutically acceptable salt thereof.

An embodiment of the invention includes a compound of Formula II or III, or a pharmaceutically acceptable salt thereof, wherein A is CH; R3is cyclopentyl optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F, OH, CH3, or CH2CH3. In a further embodiment, R3is cyclopentyl optionally substituted with 1 or 2 R5; and each R5is independently selected from the group consisting of F and CH3. In a yet further embodiment, the compound or a pharmaceutically acceptable salt thereof is a compound of Formula III or a pharmaceutically acceptable salt thereof.

An embodiment of the invention includes a compound of Formula II or III, or a pharmaceutically acceptable salt thereof, wherein A is N; R3is pyrrolidinyl, piperidinyl, or 2-azaspiro[3.3]heptanyl, each is optionally substituted with 1 R5, and wherein R5is selected from the group consisting of C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl-, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-. In a further embodiment, R3is pyrrolidine-3-yl, piperidin-4-yl, or 2-azaspiro[3.3]heptan-6-yl, each is optionally substituted with 1 R5, and wherein R5is selected from the group consisting of C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy-C1-C2alkyl-, and C1-C2fluoroalkoxy-C1-C2alkyl-. In a yet further embodiment, R3is 2-azaspiro[3.3]heptan-6-yl optionally substituted with 1 R5that is selected from the group consisting of C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy-C1-C2alkyl-, and C1-C2fluoroalkoxy-C1-C2alkyl-. In a still further embodiment, the compound or a pharmaceutically acceptable salt thereof is a compound of Formula III or a pharmaceutically acceptable salt thereof.

An embodiment of the invention includes a compound of Formula II or III, or a pharmaceutically acceptable salt thereof, wherein A is CH; R3is pyrrolidinyl, piperidinyl, or 2-azaspiro[3.3]heptanyl, each is optionally substituted with 1 R5, and wherein R5is selected from the group consisting of C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy, C1-C2fluoroalkoxy, C1-C2alkoxy-C1-C2alkyl-, C1-C2fluoroalkoxy-C1-C2alkyl-, C1-C2alkoxy-C1-C2fluoroalkyl-, and C1-C2fluoroalkoxy-C1-C2fluoroalkyl-. In a further embodiment, R3is pyrrolidine-3-yl, piperidin-4-yl, or 2-azaspiro[3.3]heptan-6-yl, each is optionally substituted with 1 R5, and wherein R5is selected from the group consisting of C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy-C1-C2alkyl-, and C1-C2fluoroalkoxy-C1-C2alkyl-. In a yet further embodiment, R3is 2-azaspiro[3.3]heptan-6-yl optionally substituted with 1 R5that is selected from the group consisting of C1-C2alkyl, C1-C2fluoroalkyl, C1-C2alkoxy-C1-C2alkyl-, and C1-C2fluoroalkoxy-C1-C2alkyl-. In a still further embodiment, the compound or a pharmaceutically acceptable salt thereof is a compound of Formula III or a pharmaceutically acceptable salt thereof.

In one embodiment, the present invention provides a compound selected from Examples 1 to 34 in the EXAMPLES section or a pharmaceutically acceptable salt thereof (or the parent/basic compound thereof where the exemplary compound, for example, is a salt) herein below.

One embodiment includes a compound selected from:6-acetyl-8-cyclobutyl-2-{[3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-cyclopentyl-2-{[3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-(2-azaspiro[3.3]heptan-6-yl)-2-{[3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-2-{[3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methyl-8-[2-methylcyclopentyl]pyrido[2,3-d]pyrimidin-7(8H)-one;3-acetyl-1-cyclopentyl-7-{[3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one;6-acetyl-8-[bicyclo[3.1.0]hexan-2-yl]-2-{[3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-[2-fluoro-2-methylcyclopentyl]-2-{[3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one; and6-acetyl-8-[2-(2,2-difluoroethyl)-2-azaspiro[3.3]heptan-6-yl]-2-{[3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one,
or a pharmaceutically acceptable salt thereof.

One embodiment includes a compound selected from:6-acetyl-8-cyclobutyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-cyclopentyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-(2-azaspiro[3.3]heptan-6-yl)-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methyl-8-[(1R,2S)-2-methylcyclopentyl]pyrido[2,3-d]pyrimidin-7(8H)-one;3-acetyl-1-cyclopentyl-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one;6-acetyl-8-[(1S,2R,5R)-bicyclo[3.1.0]hexan-2-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-[(1R,2S,5S)-bicyclo[3.1.0]hexan-2-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-[(1R,2S)-2-fluoro-2-methylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-[(1S,2R)-2-fluoro-2-methylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one; and6-acetyl-8-[2-(2,2-difluoroethyl)-2-azaspiro[3.3]heptan-6-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one,
or a pharmaceutically acceptable salt thereof.

One embodiment includes a compound selected from:6-acetyl-8-cyclobutyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-cyclopentyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-(2-azaspiro[3.3]heptan-6-yl)-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methyl-8-[(1R,2S)-2-methylcyclopentyl]pyrido[2,3-d]pyrimidin-7(8H)-one;3-acetyl-1-cyclopentyl-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one;6-acetyl-8-[(1S,2R,5R)-bicyclo[3.1.0]hexan-2-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or 6-acetyl-8-[(1R,2S,5S)-bicyclo[3.1.0]hexan-2-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or a mixture thereof;6-acetyl-8-[(1R,2S)-2-fluoro-2-methylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or 6-acetyl-8-[(1S,2R)-2-fluoro-2-methylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or a mixture thereof; and6-acetyl-8-[2-(2,2-difluoroethyl)-2-azaspiro[3.3]heptan-6-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one,
or a pharmaceutically acceptable salt thereof.

One embodiment includes a compound selected from:6-acetyl-8-cyclobutyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-cyclopentyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methyl-8-[(1R,2S)-2-methylcyclopentyl]pyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-[(1S,2S)-2-hydroxy-2-methylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or 6-acetyl-8-[(1R,2R)-2-hydroxy-2-methylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or a mixture thereof;6-acetyl-8-[(1R,2S)-2-ethylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;6-acetyl-8-[(1S,2R,5R)-bicyclo[3.1.0]hexan-2-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or 6-acetyl-8-[(1R,2S,5S)-bicyclo[3.1.0]hexan-2-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or a mixture thereof;6-acetyl-8-[(1R,2S)-2-fluoro-2-methylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or 6-acetyl-8-[(1S,2R)-2-fluoro-2-methylcyclopentyl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or a mixture thereof;6-acetyl-8-(3,3-dimethylcyclobutyl)-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one;3-acetyl-1-(3-hydroxycyclopentyl)-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one, including resolved diastereomers or as a mixture;6-acetyl-8-(cis-4-hydroxycyclohexyl)-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one; and6-acetyl-8-(trans-3-hydroxycyclobutyl)-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one, or a pharmaceutically acceptable salt thereof.

In some embodiments, the present invention provides a crystalline form of 3-acetyl-1-cyclopentyl-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one (e.g. the crystalline form as in Example 5). In some further embodiments, the crystalline form of 3-acetyl-1-cyclopentyl-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one is anhydrous. In some further embodiments, the crystalline form of anhydrous (anhydrate) 3-acetyl-1-cyclopentyl-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one is designated as “Form I” that is characterized according to its unique solid state signatures with respect to, for example, powder X-ray diffraction (PXRD), described herein (such as substantially as depicted inFIG. 1). A list of diffraction peaks expressed in terms of the degree 20 and relative intensities with a relative intensity of 3.0% (as depictedFIG. 1) is provided in Table X1 herein. As is well known in the art of powder diffraction, the relative intensities of the peaks (reflections) can vary, depending upon the sample preparation technique, the sample mounting procedure and the particular instrument employed. Moreover, instrument variation and other factors can affect the 2-theta values. Therefore, the XRPD peak assignments can vary by plus or minus about 0.2°.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising at least two characteristic peaks, in terms of 2θ, selected from at 8.0±0.2°; 18.6±0.2°; 19.1±0.2°; and 21.3±0.2°. In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising at least three characteristic peaks, in terms of 2θ, selected from at 8.0±0.2°; 18.6±0.2°; 19.1±0.2°; and 21.3±0.2°. In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising all four characteristic peaks, in terms of 2θ, selected from at 8.0±0.2°; 18.6±0.2°; 19.1±0.2°; and 21.3±0.2°.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising characteristic peaks, in terms of 2θ, at 8.0±0.2° and 18.6±0.2°.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising characteristic peaks, in terms of 2θ, at 8.0±0.2° and 19.1±0.2°.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising characteristic peaks, in terms of 2θ, at 18.6±0.2° and 19.1±0.2°.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising all three characteristic peaks, in terms of 2θ, selected from at 8.0±0.2°; 18.6±0.2°; and 19.1±0.2°.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising at least two characteristic peaks, in terms of 2θ, as those listed in Table X1.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising at least three characteristic peaks, in terms of 2θ, as those listed in Table X1.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising at least four (e.g. 4, 5, 6, 7, 8, 9, or 10) characteristic peaks, in terms of 2θ, as those listed in Table X1.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern comprising at least two characteristic peaks, in terms of 2θ, selected from at 8.0±0.2°; 18.6±0.2°; 19.1±0.2°; and 21.3±0.2°; and at least one additional characteristic peaks, in terms of 2θ, as those listed in Table X1 (e.g. peak at 23.3).

In some embodiments, Form I exhibits a powder X-ray diffraction pattern substantially as shown inFIG. 1.

The present invention includes any subset of any embodiment described herein.

The present invention includes combinations of two or more embodiments described hereinabove, or any subset thereof.

In another embodiment, the invention provides a pharmaceutical composition comprising a compound of the invention described herein, and at least one pharmaceutically acceptable excipient or carrier.

The present invention further provides use of a compound of the invention described herein in treating a disease or disorder described herein (i.e. method of treatment).

The compound of the present invention is a CDK inhibitor (e.g. a CDK4 and/or CDK6 inhibitor). Thus, the present invention further provides a method for inhibiting CDK (i.e., an activity of CDK either in vitro or in vivo), comprising contacting (including incubating) the CDK with the compound of the invention described herein.

As used herein, the compounds of invention in the pharmaceutical compositions (including formulations), uses, methods, and/or kits of the present invention described herein include compounds of Formula I or pharmaceutically acceptable salts thereof (including a compound of Formula II or III, or a pharmaceutically acceptable salt thereof, and including all embodiments and combinations of two or more embodiments described herein or any subcombination thereof, for example, any one of the compounds selected from Examples 1 to 34, or a pharmaceutically acceptable salt thereof).

As used herein, the term “contacting” refers to the bringing together of indicated moieties in an in vitro system or an in vivo system. For example, “contacting” CDK with a compound of the invention includes the administration of a compound of the present invention to an individual or patient, such as a human, having the CDK, as well as, for example, introducing a compound of the invention into a sample containing a cellular or purified preparation containing the CDK.

The present invention further provides a method for treating a disease or disorder in a patient, which method including administering to the patient in need thereof a therapeutic effective amount of a compound or a pharmaceutically acceptable salt of the invention, wherein the disease or disorder is selected from the group consisting of pulmonary hypertension, pulmonary arterial hypertension, pulmonary hypertension with left heart disease, pulmonary hypertension with lung disease and/or hypoxemia, pulmonary hypertension due to chronic thrombotic and/or embolic disease, and diseases associated with pulmonary hypertension including sarcoidosis, histiocytosis X, lymphangiomatosis and compression of pulmonary vessels.

The present invention further provides a method for treating pulmonary hypertension in a patient, which method includes administering to the patient in need thereof an effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof. In some embodiments, the compound administered is in the form of a pharmaceutically acceptable salt. In other embodiments, the compound administered is not in the form of a pharmaceutically acceptable salt (e.g., the base/parent compound is administered).

When discussing treatment of pulmonary hypertension, any one or more of these related diseases are included within that treatment as they fall within the WHO categorization of pulmonary hypertension: Group 1: pulmonary arterial hypertension (PAH); Group 2: PH with left heart disease; Group 3: PH with lung disease and/or hypoxemia; Group 4: PH due to chronic thrombotic and/or embolic disease; and Group 5: miscellaneous conditions (e.g., sarcoidosis, histiocytosis X, lymphangiomatosis and compression of pulmonary vessels).

Another embodiment of the invention includes a method for treating pulmonary arterial hypertension in a patient, which method includes administering to the patent in need thereof an effective amount of a compound or a pharmaceutically acceptable salt of the invention.

In an embodiment, the present invention further provides a method for treating abnormal cell growth in a subject, which method includes administering to the subject in need thereof a therapeutically effective amount of a compound or a pharmaceutically acceptable salt of the invention. In a further embodiment, the abnormal cell growth is cancer. Compounds or salts of the invention may be administered as single agent, or may be administered in combination with one or more other anti cancer therapeutic agents, in particular standard of care agents appropriate for the particular cancer. In a yet further embodiment, the cancer is selected from breast cancer, ovarian cancer, bladder cancer, uterine cancer, prostate cancer, lung cancer [including non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), squamous cell carcinoma or adenocarcinoma], esophageal cancer, head and neck cancer, colorectal cancer, kidney cancer (including renal cell carcinoma or RCC), liver cancer (including hepatocellular carcinoma or HCC), pancreatic cancer, stomach (i.e., gastric) cancer, and thyroid cancer. In further embodiments of the methods provided herein, the cancer is breast cancer, ovarian cancer, bladder cancer, uterine cancer, prostate cancer, lung cancer, esophageal cancer, liver cancer, pancreatic cancer, or stomach cancer.

In an embodiment, the present invention further provides a method for treating cancer in a subject, which method includes administering to the subject in need thereof a therapeutic effective amount of a compound or a pharmaceutically acceptable salt of the invention. In a further embodiment, the cancer is breast cancer, including, e.g., ER-positive/HR-positive, HER2-negative breast cancer; ER-positive/HR-positive, HER2-positive breast cancer; triple negative breast cancer (TNBC); or inflammatory breast cancer. In another embodiment, the breast cancer is endocrine resistant breast cancer, trastuzumab resistant breast cancer, or breast cancer demonstrating primary or acquired resistance to CDK4/CDK6 inhibition. In yet another embodiment, the breast cancer is advanced or metastatic breast cancer.

In a further aspect, the invention provides a method for the treatment of abnormal cell growth, in particular cancer, in a subject in need thereof, which method includes administering to the subject an amount of a compound of the invention, in combination with an amount of an additional anti cancer therapeutic agent, which amounts are together effective in treating said abnormal cell growth.

The present invention further provides use of a compound of the present invention, for treating a disease or disorder described herein (e.g. those described in the method of treatment herein).

The present invention further provides use of a compound of the present invention, in manufacturing a medicament for treating a disease or disorder described herein (e.g. those described in the method of treatment herein).

The invention also includes the following embodiments:

a compound of the present invention, including in any of the embodiments described herein, for use as a medicament;

a compound of the present invention, including any of the embodiments described herein, for use in the manufacture of a medicament;

use of a compound of the present invention, including any of the embodiments described herein, for treating abnormal cell growth such as cancer;

use of a compound of the present invention, including any of the embodiments described herein, in the manufacture of a medicament for treating abnormal cell growth such as cancer;

use of a compound of the present invention, including any of the embodiments described herein, in the manufacture of a medicament for treating pulmonary arterial hypertension;

use of a compound of the present invention, including any of the embodiments described herein, in the manufacture of a medicament for treating pulmonary hypertension (PH), or any of the diseases within the WHO categorization of PH;

a compound of the present invention, including any of the embodiments described herein, for use in the treatment of abnormal cell growth such as cancer;

a compound of the present invention, including any of the embodiments described herein, for use in the treatment of pulmonary arterial hypertension; and

a compound of the present invention, including any of the embodiments described herein, for use in the treatment of pulmonary hypertension (PH), or any of the diseases within the WHO categorization of PH.

Every Example or a pharmaceutically acceptable salt thereof may be claimed individually or grouped together in any combination with any number of each and every embodiment described herein.

The invention also relates to a pharmaceutical composition comprising a compound of the present invention, including any of the embodiments described herein, for use in the treatment of a disease or disorder described herein, for example, one selected from: pulmonary hypertension, pulmonary arterial hypertension, pulmonary hypertension with left heart disease, pulmonary hypertension with lung disease and/or hypoxemia, pulmonary hypertension due to chronic thrombotic and/or embolic disease, and diseases associated with pulmonary hypertension including sarcoidosis, histiocytosis X, lymphangiomatosis and compression of pulmonary vessels.

In another embodiment of the invention, a compound of the present invention is administered to a subject diagnosed with or at risk of developing pulmonary hypertension or PAH including, but are not limited to, idiopathic PAH, hereditary or familial PAH, and secondary pulmonary hypertension (e.g. hypertension resulting from pulmonary emboli, emphysema, pulmonary fibrosis, and congenital heart disease). In one embodiment, the subject is diagnosed with idiopathic PAH or hereditary PAH. In some embodiments, the subject at risk of developing PAH has a mutation in the gene encoding the bone morphogenetic protein type-2 receptor.

The present invention also includes a kit for the treatment or prevention of pulmonary arterial hypertension. In one embodiment, the kit comprises a compound of the present invention and an administration device. The administration device can be designed for pulmonary delivery, such as inhalers, nebulizers, insufflators, droppers, and aerosolizers. In other embodiments, the administration device can be designed for intravenous or intra-arterial delivery, such as a catheter. The compound or the pharmaceutically acceptable salt of the present invention may be optionally formulated to be stored in the administration device. The kit may further comprise instructions for administering the compound or the pharmaceutically acceptable salt of the present invention, to a subject (e.g., human) for treating or preventing PAH or other diseases discussed herein. In one embodiment, the instructions elaborate and qualify the mode of administration, for example, by specifying the days of administration for the compound or the pharmaceutically acceptable salt of the present invention during a 28-day cycle.

The invention includes a method of treating a disorder disclosed herein (e.g. PAH or cancer), where the method includes using a compound of the present invention either as monotherapy or in a combination therapy in which a subject or patient in need of treatment is administered the compound or salt of the invention in combination with one or more drugs (referred to also as active agent) approved for the treatment of the disease or disorder disclosed herein (e.g. PAH or cancer). For example, an additional active agent may include but is not limited to a prostaglandin (e.g., epoprostenol, treprostinil, iloprost, selexipag), an endothelin receptor antagonist (e.g., bosentan, ambrisentan, macitentan), a guanylate cyclase inhibitor (e.g., riociguat), vasodilators (e.g., prostacyclin and sildenafil), calcium channel blockers (e.g., amlodipine, diltiazem, and nifedipine); anticoagulants (e.g., warfarin), and diuretics. Reference to a drug, e.g., sildenafil, includes sildenafil and all pharmaceutically acceptable salts, e.g., sildenafil citrate. For another example, an additional active agent may include an anti-cancer agent such as one of the standard of care agents appropriate for the cancer to be treated.

In another aspect, a compound of the present invention is used in the manufacture of a medicament for the treatment or prevention of PAH. Yet in another aspect, a compound of the present invention is used in the manufacture of a medicament for the treatment or prevention of related diseases as discussed herein. In various embodiments, the medicament is formulated for oral administration, including both immediate release and sustained (modified) release pharmaceutical formulations. In other embodiments the medicament is formulated for administration by inhalation. In all of these embodiments, the invention provides unit dose forms of the medicament.

The invention also provides a combination that includes a compound of the present invention and another therapeutic agent. Such combination can be used in the uses and methods of the invention described herein.

The present invention also includes isotopically labelled compounds, which are identical to a compound of the present invention (e.g. a compound of Formula I, II, or III, or a pharmaceutically acceptable salt thereof), but for the fact that one or more atoms are replaced by atoms having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Examples of isotopes that can be incorporated into compounds of the present invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, sulfur, fluorine and chlorine, such as2H,3H,13C,11C,14C,15N,18O,17O,31P,32P,35S,18F, and36Cl, respectively. Compounds of the present invention, and pharmaceutically acceptable salts of said compounds, which contain the aforementioned isotopes and/or other isotopes of other atoms are within the scope of this invention. Certain isotopically labelled compounds of the present invention, for example those into which radioactive isotopes such as3H and14C are incorporated, are useful in drug and/or substrate tissue distribution assays. Tritiated, i.e.,3H, and carbon-14 i.e.,14C, isotopes are particularly preferred for their ease of preparation and detectability. Further, substitution with heavier isotopes such as deuterium, i.e.,2H, can afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements and, hence, may be preferred in some circumstances. Isotopically labelled compounds of Formula I, II, or III, or a pharmaceutically acceptable salt thereof, can generally be prepared by carrying out the procedures disclosed in the Schemes and/or in the Examples and Preparations below, by substituting a readily available isotopically labelled reagent for a non-isotopically labelled reagent.

The compounds of the invention may exhibit the phenomena of tautomerism and structural isomerism. For example, the compounds of the invention may exist in several tautomeric forms. All such tautomeric forms are included within the scope of the compounds of the invention. Tautomers may exist as mixtures of a tautomeric set in solution. In solid form, usually one tautomer predominates. Even though one tautomer may be described, the present invention includes all tautomers of the compounds of the invention.

The invention also relates to prodrugs of the compounds of the present invention. Thus, certain derivatives of compounds of the invention which may have little or no pharmacological activity themselves can, when administered to a patient, be converted into the inventive compounds, for example, by hydrolytic cleavage. Such derivatives are referred to as ‘prodrugs’. Further information on the use of prodrugs may be found in ‘Pro-drugs as Novel Delivery Systems, Vol. 14, ACS Symposium Series (T Higuchi and W Stella) and ‘Bioreversible Carriers in Drug Design’, Pergamon Press, 1987 (ed. E B Roche, American Pharmaceutical Association), the disclosures of which are incorporated herein by reference in their entireties.

Prodrugs in accordance with the invention can, for example, be produced by replacing appropriate functionalities present in the inventive compounds with certain moieties known to those skilled in the art as ‘pro-moieties’ as described, for example, in “Design of Prodrugs” by H Bundgaard (Elsevier, 1985), the disclosure of which is incorporated herein by reference in its entirety.

Some non-limiting examples of prodrugs in accordance with the invention include:

(i) where the compound contains an alcohol functionality (—OH), an ether thereof, for example, replacement of the hydrogen with (C1-C6)alkanoyloxymethyl, or with a phosphate ether group; and

(ii) where the compound contains a primary or secondary amino functionality (—NH2or —NHR where R≠H), an amide thereof, for example, replacement of one or both hydrogens with a suitably metabolically labile group, such as an amide, carbamate, urea, phosphonate, sulfonate, etc.

The term “subject” or “patient”, as used herein, refers to a mammal such as a human, a primate, cow, sheep, or a companion animal (including cat or dog).

The term “treating”, as used herein, unless otherwise indicated, means reversing, alleviating, inhibiting the progress of, or preventing the disorder or condition to which such term applies, or one or more symptoms of such disorder or condition. The term “treatment”, as used herein, unless otherwise indicated, refers to the act of treating as “treating” is defined herein. The term “treating” also includes adjuvant and neo-adjuvant treatment of a subject.

For the purposes of this invention, beneficial or desired clinical results in the treatment of cancer include, but are not limited to, one or more of the following: reducing the proliferation of (or destroying) neoplastic or cancerous cell; inhibiting metastasis or neoplastic cells; shrinking or decreasing the size of a tumor; remission of the cancer; decreasing symptoms resulting from the cancer; increasing the quality of life of those suffering from the cancer; decreasing the dose of other medications required to treat the cancer; delaying the progression of the cancer; curing the cancer; overcoming one or more resistance mechanisms of the cancer; and/or prolonging survival of patients the cancer. Positive therapeutic effects in cancer can be measured in a number of ways (see, for example, W. A. Weber, Assessing tumor response to therapy, J. Nucl. Med. 50 Suppl. 1:1S-10S (2009). For example, with respect to tumor growth inhibition (T/C), according to the National Cancer Institute (NCI) standards, a T/C less than or equal to 42% is the minimum level of anti-tumor activity. A T/C <10% is considered a high anti-tumor activity level, with T/C (%)=median tumor volume of the treated/median tumor volume of the control×100.

The phrase “therapeutically effective amount” means an amount of a compound of the invention that (i) treats or prevents the particular disease, (ii) attenuates, ameliorates, or eliminates one or more symptoms of the particular disease, or (iii) prevents or delays the onset of one or more symptoms of the particular disease described herein.

The phrase “pharmaceutically acceptable” indicates that the substance or composition must be compatible chemically and toxicologically, with the other ingredients comprising a formulation, and for the mammal being treated therewith.

Hemisalts of acids and bases may also be formed, for example, hemisulfate and hemicalcium salts. For a review on suitable salts, see Handbook of Pharmaceutical Salts: Properties, Selection, and Use by Stahl and Wermuth (Wiley-VCH, 2002).

“Abnormal cell growth”, as used herein, unless otherwise indicated, refers to cell growth that is independent of normal regulatory mechanisms (e.g., loss of contact inhibition). Abnormal cell growth may be benign (not cancerous), or malignant (cancerous).

Abnormal cell growth includes the abnormal growth of: (1) tumor cells (tumors) that show increased expression of CDK4 and/or CDK6; (2) tumors that proliferate by aberrant CDK4 and or CDK6 activation; and (3) tumors that are resistant to endocrine therapy, HER2 antagonists or CDK4/6 inhibition.

The term “additional anticancer therapeutic agent” as used herein means any one or more therapeutic agent, other than a compound of the invention, that is or can be used in the treatment of cancer. In some embodiments, such additional anticancer therapeutic agents include compounds derived from the following classes: mitotic inhibitors, alkylating agents, antimetabolites, antitumor antibiotics, anti-angiogenesis agents, topoisomerase I and II inhibitors, plant alkaloids, hormonal agents and antagonists, growth factor inhibitors, radiation, signal transduction inhibitors, such as inhibitors of protein tyrosine kinases and/or serine/threonine kinases, cell cycle inhibitors, biological response modifiers, enzyme inhibitors, antisense oligonucleotides or oligonucleotide derivatives, cytotoxics, immuno-oncology agents, and the like.

In some embodiments, the additional anticancer agent is an endocrine agent, such as an aromatase inhibitor, a SERD or a SERM.

In other embodiments, a compound of the invention may be administered in combination with a standard of care agent, such as tamoxifen, docetaxel, paclitaxel, cisplatin, capecitabine, gemcitabine, vinorelbine, exemestane, letrozole, fulvestrant, anastrozole or trastuzumab.

As used herein “cancer” refers to any malignant and/or invasive growth or tumor caused by abnormal cell growth. Cancer includes solid tumors named for the type of cells that form them, cancer of blood, bone marrow, or the lymphatic system. Examples of solid tumors include sarcomas and carcinomas. Cancers of the blood include, but are not limited to, leukemia, lymphoma and myeloma. Cancer also includes primary cancer that originates at a specific site in the body, a metastatic cancer that has spread from the place in which it started to other parts of the body, a recurrence from the original primary cancer after remission, and a second primary cancer that is a new primary cancer in a person with a history of previous cancer of a different type from the latter one.

In some embodiments of the methods provided herein, the cancer is selected from the group consisting of breast cancer, ovarian cancer, bladder cancer, uterine cancer, prostate cancer, lung cancer (including NSCLC), esophageal cancer, liver cancer, pancreatic cancer and stomach cancer.

This invention also comprises a pharmaceutical formulation comprising a therapeutically effective amount of a compound of the invention, together with a pharmaceutically acceptable carrier. For preparing pharmaceutical compositions with the compounds of the present invention, pharmaceutically acceptable carriers can be either a solid or liquid. Solid form preparations include powders, tablets, pills, capsules, cachets, suppositories, and dispensable granules. A solid carrier can be one or more substances which may also act as diluents, flavoring agents, binders, preservatives, tablet disintegrating agents, or an encapsulating material. For tablet dosage forms, depending on dose, a compound or a pharmaceutically acceptable salt of the invention, may make up from 1 wt % to 80 wt % of the dosage form, typically from 5 wt % to 60 wt %, more typically from about 10 wt % to about 35 wt %, or even more typically from about 15 wt % to about 25 wt % of the dosage form. In specific embodiments, a compound or a pharmaceutically acceptable salt of the invention, comprises about 20 wt % of the dosage form by weight.

In the solid dosage forms of the invention, the carrier may comprise a variety of pharmaceutically acceptable excipients, including, for example, diluents, disintegrants, binders, lubricants, glidants and surface-active agents. Formulations may also include excipients such as preservatives, anti-oxidants, flavors and colorants, as well as other excipients known in the art.

Solid dosage forms, such as tablets, typically contain diluents, e.g., lactose (monohydrate, spray-dried monohydrate, anhydrous and the like), mannitol, xylitol, dextrose, sucrose, sorbitol, compressible sugar, microcrystalline cellulose, powdered cellulose, starch, pregelatinized starch, dextrates, dextran, dextrin, dextrose, maltodextrin, calcium carbonate, dibasic calcium phosphate, tribasic calcium phosphate, calcium sulfate, magnesium carbonate, magnesium oxide, poloxamers, polyethylene oxide, hydroxypropyl methyl cellulose and mixtures thereof. Different types of microcrystalline cellulose may be suitable for use in the formulations described herein. Examples of microcrystalline cellulose include Avicel® types: PH101, PH102, PH103, PH105, PH 112, PH113, PH200, PH301, and other types of microcrystalline cellulose, such as silicified microcrystalline cellulose (SMCC). In some embodiments, the diluent is selected from the group consisting of microcrystalline cellulose, lactose monohydrate, mannitol, sorbitol, xylitol, magnesium carbonate, dibasic calcium phosphate, tribasic calcium phosphate, or mixtures thereof. In certain embodiments, the diluent comprises microcrystalline cellulose. In some embodiments, the diluent comprises one or more types of microcrystalline cellulose, for example Avicel® PH105, Avicel® PH200 or mixtures thereof. In some such embodiments, the diluent excludes lactose monohydrate. In other such embodiments, the diluent comprises microcrystalline cellulose and further comprises lactose monohydrate. Diluents frequently comprise from about 25 wt % to about 75 wt % of the solid dosage form, and preferably from about 50 wt % to about 75 wt % of the dosage form.

Solid dosage forms frequently contain disintegrants. Examples of disintegrants include sodium starch glycolate, sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, croscarmellose sodium, crospovidone, polyvinylpyrrolidone, methylcellulose, microcrystalline cellulose, lower alkyl-substituted hydroxypropyl cellulose, starch, pregelatinized starch, and sodium alginate. In some embodiments, the disintegrant is crospovidone. Any grade of crospovidone can be used; for example CL, CL-SF and XL grades of crospovidone are suitable for use in the formulations described herein. Specific examples include Kollidon, Kollidon CL®, Kollidon CL-M®, Polyplasdone XL®, Polyplasdone XL-100, and Polyplasdone INF-100. In some embodiments, the carrier comprises at least one disintegrant selected from the group consisting of crospovidone, croscarmellose sodium and sodium starch glycolate. In specific embodiments, the disintegrant is crospovidone. Disintegrants frequently comprise from about 1 wt % to about 25 wt %, preferably from about 5 wt % to about 20 wt %, more preferably from about 5 wt % to about 10 wt % of the dosage form.

Binders may be used to impart cohesive qualities to a tablet formulation. Suitable binders include microcrystalline cellulose, gelatin, sugars, polyethylene glycol, natural and synthetic gums, polyvinylpyrrolidone, pregelatinized starch, hydroxypropyl cellulose, and hydroxypropyl methylcellulose. In some embodiments, the binder is selected from the group consisting of microcrystalline cellulose, hydroxypropyl cellulose and hydroxypropyl methylcellulose. In specific embodiments, the binder is microcrystalline cellulose, e.g. Avicel® PH105. When present, binders may comprise from about 0 wt % to about 15 wt %, or from about 0.2 wt % to about 10 wt % of the dosage form. In some embodiments, the binder comprises about 5 wt % to about 10 wt % of the dosage form. In particular embodiments, the binder comprises about 10 wt % of the dosage form.

Solid dosage forms frequently contain one or more lubricants. Examples of lubricants include magnesium stearate, calcium stearate, zinc stearate, sodium stearyl fumarate, mixtures of magnesium stearate with sodium lauryl sulfate, or mixtures of two or more of these. In some embodiments, the lubricant is magnesium stearate and/or sodium stearyl fumarate. In some embodiments, the lubricant is magnesium stearate. In some such embodiments, the solid dosage form is a tablet comprising intragranular and extragranular magnesium stearate. In other embodiments, the solid dosage form is a tablet comprising intragranular magnesium stearate and extragranular sodium stearyl fumarate. When present, lubricants frequently comprise from about 0.25 wt % to about 10 wt %, preferably from about 0.5 wt % to about 6 wt % of the dosage form.

Tablets may also compromise glidants, for example silicon dioxide, colloidal silicon dioxide, magnesium silicate, magnesium trisilicate, talc, and other forms of silicon dioxide, such as aggregated silicates and hydrated silica. In some embodiments, the glidant is silicon dioxide. When present, glidants may comprise from about 0 wt % to about 10 wt %, preferably from about 0.2 wt % to about 5 wt %, or from about 0.5 wt % to about 2 wt % of the tablet.

Tablets may optionally include surface-active agents, such as sodium lauryl sulfate and polysorbate 80. When present, surface-active agents may comprise from 0 wt % to 10 wt %, or preferably 0.2 wt % to 5 wt % of the tablet.

In general, the solid dosage forms of the invention are prepared according to methods usual in pharmaceutical chemistry. Selected carrier (or excipients) may be incorporated along with the active pharmaceutical ingredient into either or both of the extragranular or intragranular compartments.

The therapeutically effective dose of a compound or a pharmaceutically acceptable salt of the invention, will vary from approximately 0.01 mg/kg to approximately 100 mg/kg of body weight per day. Typical adult doses will be approximately 0.1 mg to approximately 3000 mg per day. More typically, the therapeutically effective adult dose of a compound or a pharmaceutically acceptable salt of the invention, is 50 mg, 75 mg, 100 mg, 125 mg, 175 mg, or 200 mg per day. The quantity of active component in a unit dose preparation may be varied or adjusted from approximately 0.1 mg to approximately 500 mg, preferably about 25 mg to about 200 mg according to the particular application. The composition can, if desired, also contain other compatible therapeutic agents. A subject in need of treatment with a compound or a pharmaceutically acceptable salt of the invention, is administered a dosage of about 0.6 to about 500 mg per day, and preferably about 25 mg to about 200 mg per day, either singly or in multiple doses over a 24-hour period. Such treatment may be repeated at successive intervals for as long as necessary.

The compounds of the present invention (including compounds of Formula I, II, or III, or salts thereof) may contain asymmetric or chiral centers, and, therefore, exist in different stereoisomeric forms. Unless specified otherwise, it is intended that all stereoisomeric forms of the compounds of the present invention as well as mixtures thereof, including racemic mixtures, form part of the present invention. In addition, the present invention embraces all geometric and positional isomers. For example, if a compound of the present invention incorporates a double bond or a fused ring, both the cis- and trans-forms, as well as mixtures, are embraced within the scope of the invention.

Chiral compounds of the invention (and chiral precursors thereof) may be obtained in enantiomerically-enriched form using chromatography, typically high pressure liquid chromatography (HPLC) or supercritical fluid chromatography (SFC), on a resin with an asymmetric stationary phase and with a mobile phase consisting of a hydrocarbon, typically heptane or hexane, containing from 0 to 50% isopropanol, typically from 2 to 20%, and from 0 to 5% of an alkylamine, typically 0.1% diethylamine (DEA) or isopropylamine. Concentration of the eluent affords the enriched mixture.

Diastereomeric mixtures can be separated into their individual diastereoisomers on the basis of their physical chemical differences by methods well known to those skilled in the art, such as by chromatography and/or fractional crystallization. Enantiomers can be separated by converting the enantiomeric mixture into a diastereomeric mixture by reaction with an appropriate optically active compound (e.g. chiral auxiliary such as a chiral alcohol or Mosher's acid chloride), separating the diastereoisomers and converting (e.g. hydrolyzing) the individual diastereoisomers to the corresponding pure enantiomers. Enantiomers can also be separated by use of a chiral HPLC column. Alternatively, the specific stereoisomers may be synthesized by using an optically active starting material, by asymmetric synthesis using optically active reagents, substrates, catalysts or solvents, or by converting one stereoisomer into the other by asymmetric transformation.

According to the methods of the invention, a compound of the present invention or a combination is preferably administered in the form of a pharmaceutical composition. Accordingly, a compound of the present invention or a combination thereof can be administered to a patient separately or together in any conventional oral, rectal, transdermal, parenteral (e.g., intravenous, intramuscular or subcutaneous), intracisternal, intravaginal, intraperitoneal, topical (e.g., powder, ointment, cream, spray or lotion), buccal or nasal dosage form (e.g., spray, drops or inhalant).

The compounds of the invention or combinations can be administered alone but will generally be administered in an admixture with one or more suitable pharmaceutical excipients, adjuvants, diluents or carriers known in the art and selected with regard to the intended route of administration and standard pharmaceutical practice. The compound of the invention or combination may be formulated to provide immediate-, delayed-, modified-, sustained-, pulsed- or controlled-release dosage forms depending on the desired route of administration and the specificity of release profile, commensu-rate with therapeutic needs.

The pharmaceutical composition comprises a compound of the invention or a combination thereof in an amount generally in the range of from about 1% to about 75%, 80%, 85%, 90% or even 95% (by weight) of the composition, usually in the range of about 1%, 2% or 3% to about 50%, 60% or 70%, more frequently in the range of about 1%, 2% or 3% to less than 50% such as about 25%, 30% or 35%.

Methods of preparing various pharmaceutical compositions with a specific amount of active compound are known to those skilled in this art. For examples, see Remington: The Practice of Pharmacy, Lippincott Williams and Wilkins, Baltimore Md. 20.sup.th ed. 2000.

Compositions suitable for parenteral injection generally include pharmaceutically acceptable sterile aqueous or nonaqueous solutions, dispersions, suspensions, or emulsions, and sterile powders for reconstitution into sterile injectable solutions or dis-persions. Examples of suitable aqueous and nonaqueous carriers or diluents (including solvents and vehicles) include water, ethanol, polyols (propylene glycol, polyeth-ylene glycol, glycerol, and the like), suitable mixtures thereof, triglycerides including vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate. A preferred carrier is Miglyol® brand caprylic/capric acid ester with glycerine or pro-pylene glycol (e.g., Miglyol® 812, Miglyol® 829, Miglyol® 840) available from Condea Vista Co., Cranford, N.J. Proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants.

These compositions for parenteral injection may also contain excipients such as preserving, wetting, emulsifying, and dispersing agents. Prevention of microorganism contamination of the compositions can be accomplished with various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, and the like. It may also be desirable to include isotonic agents, for example, sugars, sodium chloride, and the like. Prolonged absorption of injectable pharmaceutical compositions can be brought about by the use of agents capable of delaying absorption, for exam-ple, aluminum monostearate and gelatin.

Solid dosage forms for oral administration include capsules, tablets, chews, loz-enges, pills, powders, and multi-particulate preparations (granules). In such solid dos-age forms, a compound of the present invention or a combination is admixed with at least one inert excipient, diluent or carrier. Suitable excipients, diluents or carriers in-clude materials such as sodium citrate or dicalcium phosphate and/or (a) one or more fillers or extenders (e.g., microcrystalline cellulose (available as Avicel™ from FMC Corp.) starches, lactose, sucrose, mannitol, silicic acid, xylitol, sorbitol, dextrose, calci-um hydrogen phosphate, dextrin, alpha-cyclodextrin, beta-cyclodextrin, polyethylene glycol, medium chain fatty acids, titanium oxide, magnesium oxide, aluminum oxide and the like); (b) one or more binders (e.g., carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, gelatin, gum arabic, ethyl cellu-lose, polyvinyl alcohol, pullulan, pregelatinized starch, agar, tragacanth, alginates, gel-atin, polyvinylpyrrolidone, sucrose, acacia and the like); (c) one or more humectants (e.g., glycerol and the like); (d) one or more disintegrating agents (e.g., agar-agar, calci-um carbonate, potato or tapioca starch, alginic acid, certain complex silicates, sodium carbonate, sodium lauryl sulphate, sodium starch glycolate (available as Ex-plotab™ from Edward Mendell Co.), cross-linked polyvinyl pyrrolidone, croscarmel-lose sodium A-type (available as Ac-di-sol™), polyacrilin potassium (an ion ex-change resin) and the like); (e) one or more solution retarders (e.g., paraffin and the like); (f) one or more absorption accelerators (e.g., quaternary ammonium compounds and the like); (g) one or more wetting agents (e.g., cetyl alcohol, glycerol monostearate and the like); (h) one or more adsorbents (e.g., kaolin, bentonite and the like); and/or (i) one or more lubricants (e.g., talc, calcium stearate, magnesium stearate, stearic acid, polyoxyl stearate, cetanol, talc, hydrogenated caster oil, sucrose esters of fatty acid, di-methylpolysiloxane, microcrystalline wax, yellow beeswax, white beeswax, solid poly-ethylene glycols, sodium lauryl sulfate and the like). In the case of capsules and tab-lets, the dosage forms may also comprise buffering agents.

Solid compositions of a similar type may also be used as fillers in soft or hard filled gelatin capsules using such excipients as lactose or milk sugar, as well as high molecular weight polyethylene glycols, and the like.

Solid dosage forms such as tablets, dragees, capsules, and granules may be prepared with coatings and shells, such as enteric coatings and others well known in the art. They may also contain opacifying agents, and can also be of such composition that they release the compound of the present invention and/or the additional pharma-ceutical agent in a delayed manner. Examples of embedding compositions that can be used are polymeric substances and waxes. The drug may also be in micro-encapsulated form, if appropriate, with one or more of the above-mentioned excipients.

For tablets, the active agent will typically comprise less than 50% (by weight) of the formulation, for example less than about 10% such as 5% or 2.5% by weight. The predominant portion of the formulation comprises fillers, diluents, disintegrants, lubri-cants and optionally, flavors. The composition of these excipients is well known in the art. Frequently, the fillers/diluents will comprise mixtures of two or more of the following components: microcrystalline cellulose, mannitol, lactose (all types), starch, and di-calcium phosphate. The filler/diluent mixtures typically comprise less than 98% of the formulation and preferably less than 95%, for example 93.5%. Preferred disintegrants include Ac-di-sol™, Explotab™, starch and sodium lauryl sulphate. When present a disintegrant will usually comprise less than 10% of the formulation or less than 5%, for example about 3%. A preferred lubricant is magnesium stearate. When present a lubricant will usually comprise less than 5% of the formulation or less than 3%, for ex-ample about 1%.

Tablets may be manufactured by standard tabletting processes, for example, direct compression or a wet, dry or melt granulation, melt congealing process and extru-sion. The tablet cores may be mono or multi-layer(s) and can be coated with appropri-ate overcoats known in the art.

Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups, and elixirs. In addition to the compound of the present invention or the combination, the liquid dosage form may contain inert diluents commonly used in the art, such as water or other solvents, solubilizing agents and emulsifiers, as for example, ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, dime-thylformamide, oils (e.g., cottonseed oil, groundnut oil, corn germ oil, olive oil, castor oil, sesame seed oil and the like), Miglyole® (available from CONDEA Vista Co., Cran-ford, N.J.), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, or mixtures of these substances, and the like.

Besides such inert diluents, the composition may also include excipients, such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and per-fuming agents.

Oral liquid forms of the compounds of the invention or combinations include solutions, wherein the active compound is fully dissolved. Examples of solvents include all pharmaceutically precedented solvents suitable for oral administration, particularly those in which the compounds of the invention show good solubility, e.g., polyeth-ylene glycol, polypropylene glycol, edible oils and glyceryl- and glyceride-based sys-tems. Glyceryl- and glyceride-based systems may include, for example, the following branded products (and corresponding generic products): Captex™ 355 EP (glyceryl tricaprylate/caprate, from Abitec, Columbus Ohio), Crodamol™ GTC/C (medium chain triglyceride, from Croda, Cowick Hall, UK) or Labrafac™ CC (medium chain triglyides, from Gattefosse), Captex™ 500P (glyceryl triacetate i.e. triacetin, from Abitec), Cap-mul™ MCM (medium chain mono- and diglycerides, fromAbitec), Migyol™ 812 (caprylic/capric triglyceride, from Condea, Cranford N.J.), Migyol™ 829 (caprylic/capric/succinic triglyceride, from Condea), Migyol™ 840 (propylene glycol dicaprylate/dicaprate, from Condea), Labrafil™ M1944CS (oleoyl macrogol-6 glycer-ides, from Gattefosse), Peceol™ (glyceryl monooleate, from Gattefosse) and Maisine™ 35-1 (glyceryl monooleate, from Gattefosse). Of particular interest are the medium chain (about C.sub.8 to C.sub.10) triglyceride oils. These solvents frequently make up the predominant portion of the composition, i.e., greater than about 50%, usu-ally greater than about 80%, for example about 95% or 99%. Adjuvants and additives may also be included with the solvents principally as taste-mask agents, palatability and flavoring agents, antioxidants, stabilizers, texture and viscosity modifiers and solu-bilizers.

Compositions for rectal or vaginal administration preferably comprise suppositories, which can be prepared by mixing a compound of the present invention or a com-bination with suitable non-irritating excipients or carriers, such as cocoa butter, poly-ethylene glycol or a suppository wax which are solid at ordinary room temperature, but liquid at body temperature, and therefore, melt in the rectum or vaginal cavity thereby releasing the active component(s).

Dosage forms for topical administration of the compounds of the present invention or combinations include ointments, creams, lotions, powders and sprays. The drugs are admixed with a pharmaceutically acceptable excipient, diluent or carrier, and any preservatives, buffers, or propellants that may be required.

Many of the present compounds are poorly soluble in water, e.g., less than about 1 μg/mL. Therefore, liquid compositions in solubilizing, non-aqueous solvents such as the medium chain triglyceride oils discussed above are a preferred dosage form for these compounds.

Solid amorphous dispersions, including dispersions formed by a spray-drying process, are also a preferred dosage form for the poorly soluble compounds of the in-vention. By “solid amorphous dispersion” is meant a solid material in which at least a portion of the poorly soluble compound is in the amorphous form and dispersed in a water-soluble polymer. By “amorphous” is meant that the poorly soluble compound is not crystalline. By “crystalline” is meant that the compound exhibits long-range order in three dimensions of at least 100 repeat units in each dimension. Thus, the term amor-phous is intended to include not only material which has essentially no order, but also material which may have some small degree of order, but the order is in less than three dimensions and/or is only over short distances. Amorphous material may be character-ized by techniques known in the art such as powder x-ray diffraction (PXRD) crystal-lography, solid state NMR, or thermal techniques such as differential scanning calo-rimetry (DSC).

In some embodiments, at least a major portion (i.e., at least about 60 wt %) of the poorly soluble compound in the solid amorphous dispersion is amorphous. The compound can exist within the solid amorphous dispersion in relatively pure amorphous domains or regions, as a solid solution of the compound homogeneously distributed throughout the polymer or any combination of these states or those states that lie intermediate between them. Preferably, the solid amorphous dispersion is substantially homogeneous so that the amorphous compound is dispersed as homogeneously as possible throughout the polymer. As used herein, “substantially homogeneous” means that the fraction of the compound that is present in relatively pure amorphous domains or re-gions within the solid amorphous dispersion is relatively small, on the order of less than 20 wt %, and preferably less than 10 wt % of the total amount of drug.

Water-soluble polymers suitable for use in the solid amorphous dispersions should be inert, in the sense that they do not chemically react with the poorly soluble compound in an adverse manner, are pharmaceutically acceptable, and have at least some solubility in aqueous solution at physiologically relevant pHs (e.g. 1-8). The pol-ymer can be neutral or ionizable, and should have an aqueous-solubility of at least 0.1 mg/mL over at least a portion of the pH range of 1-8.

Water-soluble polymers suitable for use with the present invention may be cellu-losic or non-cellulosic. The polymers may be neutral or ionizable in aqueous solution. Of these, ionizable and cellulosic polymers are preferred, with ionizable cellulosic pol-ymers being more preferred.

The solid amorphous dispersions may be prepared according to any process for forming solid amorphous dispersions that results in at least a major portion (at least 60%) of the poorly soluble compound being in the amorphous state. Such processes include mechanical, thermal and solvent processes. Exemplary mechanical processes include milling and extrusion; melt processes including high temperature fusion, sol-vent-modified fusion and melt-congeal processes; and solvent processes including non-solvent precipitation, spray coating and spray drying. See, for example, the following U.S. Patents, the pertinent disclosures of which are incorporated herein by reference: U.S. Pat. Nos. 5,456,923 and 5,939,099, which describe forming dispersions by extrusion processes; U.S. Pat. Nos. 5,340,591 and 4,673,564, which describe forming dispersions by milling processes; and U.S. Pat. Nos. 5,707,646 and 4,894,235, which describe forming dispersions by melt congeal processes. In a preferred process, the solid amorphous dispersion is formed by spray drying, as disclosed in European Patent Application Publication No. 0 901 786 A2. In this process, the compound and polymer are dissolved in a solvent, such as acetone or methanol, and the solvent is then rapidly removed from the solution by spray drying to form the solid amorphous dispersion. The solid amorphous disper-sions may be prepared to contain up to about 99 wt % of the compound, e.g., 1 wt %, 5 wt %, 10 wt %, 25 wt %, 50 wt %, 75 wt %, 95 wt %, or 98 wt % as desired.

The solid dispersion may be used as the dosage form itself or it may serve as a manufacturing-use-product (MUP) in the preparation of other dosage forms such as capsules, tablets, solutions or suspensions. An example of an aqueous suspension is an aqueous suspension of a 1:1 (w/w) compound/HPMCAS-HF spray-dried dispersion containing 2.5 mg/mL of compound in 2% polysorbate-80. Solid dispersions for use in a tablet or capsule will generally be mixed with other excipients or adjuvants typically found in such dosage forms. For example, an exemplary filler for capsules contains a 2:1 (w/w) compound/HPMCAS-MF spray-dried dispersion (60%), lactose (fast flow) (15%), microcrystalline cellulose (e.g., Avicel.sup.(R0-102) (15.8%), sodium starch (7%), sodium lauryl sulfate (2%) and magnesium stearate (1%).

The HPMCAS polymers are available in low, medium and high grades as Aqoa.sup®-LF, Aqoat.sup®-MF and Aqoat.sup®-HF respectively from Shin-Etsu Chemical Co., LTD, Tokyo, Japan. The higher MF and HF grades are generally preferred.

The following paragraphs describe exemplary formulations, dosages, etc. useful for non-human animals. The administration of the compounds of the present invention and combinations of the compounds of the present invention with anti-obesity agents can be effected orally or non-orally.

An amount of a compound of the present invention or combination of a com-pound of the present invention with another anti-obesity agent is administered such that an effective dose is received. Generally, a daily dose that is administered orally to an animal is between about 0.01 and about 1,000 mg/kg of body weight, e.g., between about 0.01 and about 300 mg/kg or between about 0.01 and about 100 mg/kg or between about 0.01 and about 50 mg/kg of body weight, or between about 0.01 and about 25 mg/kg, or about 0.01 and about 10 mg/kg or about 0.01 and about 5 mg/kg.

Conveniently, a compound of the present invention (or combination) can be carried in the drinking water so that a therapeutic dosage of the compound is ingested with the daily water supply. The compound can be directly metered into drinking water, preferably in the form of a liquid, water-soluble concentrate (such as an aqueous solution of a water-soluble salt).

Conveniently, a compound of the present invention (or combination thereof) can also be added directly to the feed, as such, or in the form of an animal feed supplement, al-so referred to as a premix or concentrate. A premix or concentrate of the compound in an excipient, diluent or carrier is more commonly employed for the inclusion of the agent in the feed. Suitable excipients, diluents or carriers are liquid or solid, as desired, such as water, various meals such as alfalfa meal, soybean meal, cottonseed oil meal, linseed oil meal, corncob meal and corn meal, molasses, urea, bone meal, and mineral mixes such as are commonly employed in poultry feeds. A particularly effective excipient, diluent or carrier is the respective animal feed itself; that is, a small portion of such feed. The carrier facilitates uniform distribution of the compound in the finished feed with which the premix is blended. Preferably, the compound is thoroughly blended into the premix and, subsequently, the feed. In this respect, the compound may be dispersed or dissolved in a suitable oily vehicle such as soybean oil, corn oil, cottonseed oil, and the like, or in a volatile organic solvent and then blended with the carrier. It will be appreciated that the proportions of compound in the concentrate are capable of wide variation since the amount of the compound in the finished feed may be adjusted by blending the appropriate proportion of premix with the feed to obtain a desired level of compound.

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

If the supplement is used as a top dressing for the feed, it likewise helps to ensure uniformity of distribution of the compound across the top of the dressed feed.

Drinking water and feed effective for increasing lean meat deposition and for improving lean meat to fat ratio are generally prepared by mixing a compound of the present invention with a sufficient amount of animal feed to provide from about 10−3to about 500 ppm of the compound in the feed or water.

The preferred medicated swine, cattle, sheep and goat feed generally contain from about 1 to about 400 grams of a compound of the present invention (or combination) per ton of feed, the optimum amount for these animals usually being about 50 to about 300 grams per ton of feed.

The preferred poultry and domestic pet feeds usually contain about 1 to about 400 grams and preferably about 10 to about 400 grams of a compound of the present invention (or combination thereof) per ton of feed.

For parenteral administration in animals, the compounds of the present invention (or combination) may be prepared in the form of a paste or a pellet and administered as an implant, usually under the skin of the head or ear of the animal in which increase in lean meat deposition and improvement in lean meat to fat ratio is sought.

Paste Formulations may be prepared by dispersing the drug in a pharmaceutically acceptable oil such as peanut oil, sesame oil, corn oil or the like.

Pellets containing an effective amount of a compound of the present invention, pharmaceutical composition, or combination may be prepared by admixing a com-pound of the present invention or combination with a diluent such as carbowax, carnuba wax, and the like, and a lubricant, such as magnesium or calcium stearate, may be added to improve the pelleting process.

It is, of course, recognized that more than one pellet may be administered to an animal to achieve the desired dose level which will provide the increase in lean meat deposition and improvement in lean meat to fat ratio desired. Moreover, implants may also be made periodically during the animal treatment period in order to maintain the proper drug level in the animal's body.

The present invention has several advantageous veterinary features. For the pet owner or veterinarian who wishes to increase leanness and/or trim unwanted fat from pet animals, the instant invention provides the means by which this may be accomplished. For poultry, beef and swine breeders, utilization of the method of the present invention yields leaner animals that command higher sale prices from the meat industry.

Preparation

Compounds of the present invention may be synthesized by synthetic routes that include processes analogous to those well-known in the chemical arts, particularly in light of the description contained herein. The starting materials are generally availa-ble from commercial sources such as Aldrich Chemicals (Milwaukee, Wis.) or are readily prepared using methods well known to those skilled in the art (e.g., prepared by meth-ods generally described in Louis F. Fieser and Mary Fieser, Reagents for Organic Syn-thesis, v. 1-19, Wiley, New York (1967-1999 ed.), or Beilsteins Handbuch der organ-ischen Chemie, 4, Aufl. ed. Springer-Verlag, Berlin, including supplements (also avail-able via the Beilstein online database)). Many of the compounds used herein, are re-lated to, or are derived from compounds in which there is a large scientific interest and commercial need, and accordingly many such compounds are commercially available or are reported in the literature or are easily prepared from other commonly available substances by methods which are reported in the literature.

For illustrative purposes, the reaction schemes depicted below provide potential routes for synthesizing the compounds of the present invention as well as key inter-mediates. For a more detailed description of the individual reaction steps, see the Examples section below. Those skilled in the art will appreciate that other synthetic routes may be used to synthesize the inventive compounds. Although specific starting materials and reagents are discussed below, other starting materials and reagents can be easily substituted to provide a variety of derivatives and/or reaction conditions. In addition, many of the compounds prepared by the methods described below can be further modified in light of this disclosure using conventional chemistry well known to those skilled in the art.

Unless stated otherwise, the variables in Schemes A-L have the same meanings as defined herein. The amines mentioned herein may constitute protected amines that are deprotected under standard conditions known to those skilled in the art. The need for such protection/deprotection will vary depending on the nature of the remote functionality and the conditions of the preparation methods. The need for such protection is readily determined by one skilled in the art. The use of such protection/deprotection methods is also within the skill in the art. For a general description of protecting groups and their use, see T. W. Greene, Protective Groups in Organic Synthesis, John Wiley & Sons, New York, 1991.

For example, certain compounds contain primary amines or carboxylic acid functionalities that may interfere with reactions at other sites of the molecule if left unprotected. Accordingly, such functionalities may be protected by an appropriate protecting group, which may be removed in a subsequent step. Suitable protecting groups for amine and carboxylic acid protection include those protecting groups commonly used in peptide synthesis (such as N-tert-butoxycarbonyl (Boc), benzyloxycarbonyl (Cbz), and 9-fluorenylmethylenoxycarbonyl (Fmoc) for amines, and lower alkyl or benzyl esters for carboxylic acids), which are generally not chemically reactive under the reaction conditions described and can typically be removed without chemically altering other functionality in the compounds of the present invention.

The Reaction Schemes described below are intended to provide a general description of the methodology employed in the preparation of the compounds of the present invention. Some of the compounds of the present invention contain a single chiral center. In the following Schemes, the general methods for the preparation of the compounds are shown either in racemic or enantioenriched form. It will be apparent to one skilled in the art that all of the synthetic transformations can be conducted in a precisely similar manner whether the materials are enantioenriched or racemic. Moreover, the resolution to the desired optically active material may take place at any desired point in the sequence, using well-known methods such as described herein and in the chemistry literature.

In the following Reaction Schemes, the variables R1, R2, R3, and R4are as described in the Summary except where otherwise noted.

As illustrated in Scheme A, oxidation of A-1 to afford the mixture A-2 [sulfoxide (n=1) and/or sulfone (n=2)] can be carried out under appropriate conditions, such as with potassium peroxymonosulfate (Oxone®) in tetrahydrofuran (THF) and water as solvent (this oxidation can be used in e.g. Scheme D). A subsequent nucleophilic aromatic substitution (SNAr reaction) provides the 2-substituted pyrido[2,3-d]pyrimidin-7(8H)-ones A-3. The SNAr reactions are typically carried out in the presence of a suitable base such as N,N-diisopropylethylamine (DIPEA) in a suitable solvent such as dimethyl sulfoxide (DMSO) or tetrahydrofuran (THF).

As illustrated in Scheme B, treatment of B-1 such as 6-bromo-2-chloro-8-cyclopentyl-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one (purchased or synthesized in a manner similar to that described by Duan, S. et al.,Org. Process Res. Dev.2016, 20, 1191-1202) with a vinyl ether precursor such as tributyl(1-ethoxyethenyl)stannane or 1-(ethenyloxy)butane, under standard palladium-catalyzed cross-coupling conditions, affords the vinyl ether B-2 where R is H. Alternatively, substituted vinyl stannane or alkoxy vinyl ether reagents could be employed to afford B-2 intermediates wherein R is other than H, for example, wherein R is methyl optionally substituted with one or more fluorine atoms. SNAr reaction of B-2 with various substituted amines in the presence of a base such as DIPEA in a suitable solvent such as DMSO provides B-3. Hydrolysis of the vinyl ether under acidic conditions, such as aqueous HCl in THF, provides the 2-substituted pyrido[2,3-d]pyrimidin-7(8H)-ones B-4 (wherein R2is for example, CH2R, and R is H or methyl optionally substituted with one or more fluorine atoms).

An alternative synthetic route to B-4 is depicted in Scheme C. Hydrolysis of vinyl ether B-2 in the presence of an acid, such as aqueous HCl in THF, affords C-1. SNAr reaction of C-1 with various substituted amines in the presence of a base, such as DIPEA, in a suitable solvent, such as DMSO, provides B-4.

Scheme D illustrates an alternative SNAr reaction of B-1 with various substituted amines to provide pyrimidine D-1. Functionalization of D-1 at the C(6) position is achieved by treatment with a suitable substituted vinyl stannane or an alkoxy vinyl ether under standard cross-coupling conditions known to those skilled in the art, followed by the acid-mediated hydrolysis of the resulting vinyl ether, to afford the ketone intermediate B-4. Alternatively, an SNAr reaction of B-1 with sodium methanethiolate in a suitable solvent such as THF or DMSO generates methylthiopyrimidine D-2, which is followed by standard cross-coupling conditions and acid-mediated hydrolysis to afford ketone D-3. Following the procedure described in Scheme A would provide B-4.

As illustrated in Scheme E, SNAr reaction of E-1 with various substituted amines under basic conditions, such as with triethylamine in acetonitrile as solvent, provides E-2. A Heck reaction of E-2 with appropriately substituted enoic acids and concomitant cyclization using acetic anhydride provides the pyrido[2,3-d]pyrimidin-7(8H)-ones E-3. Bromination at the C(6) position using standard reagents such as bromine in a suitable solvent such as dichloromethane gives the bromide E-4. An SNAr reaction with various substituted amines as previously discussed provides E-5. Installation of the ketone moiety at the C(6) position is achieved by treating it with a vinyl stannane or alkoxy vinyl ether under standard cross-coupling conditions followed by the acid-mediated hydrolysis of the corresponding vinyl ether to provide E-6.

As illustrated in Scheme F, SNAr reaction of ethyl 4-chloro-2-(methylthio)pyrimidine-5-carboxylate (F-1; purchased or synthesized in a manner similar to that described by Federico, S. et al.,J. Med. Chem.2014, 57, 6210-6225) with various substituted amines under basic conditions yields F-2. Conversion of the ester functionality in F-2 to the corresponding ketone is carried out using standard methods known in the art to provide F-6. For example, lithium aluminum hydride (LiAlH4) reduction of F-2 generates alcohol F-3, which is followed by manganese(IV) oxide oxidation to afford aldehyde F-4. Addition of a suitable Grignard reagent such as methylmagnesium chloride (where R1=Me) to F-4 generates alcohol F-5, which is then converted to ketone F-6 through manganese(IV) oxide oxidation. The pyrido[2,3-d]pyrimidin-7(8H)-one F-7 is obtained through a cyclocondensation using either standard Horner-Wadsworth-Emmons reaction conditions or ethyl acetate and a suitable base such as sodium bis(trimethylsilyl)amide. Bromination at C(6), which provides F-8, is followed by oxidation of the thiomethyl group at C(2) under standard conditions described previously (Scheme A), yielding F-9. SNAr reaction with various substituted amines as previously discussed provides E-5. E-6 is then obtained from E-5 as described in Scheme E. Alternatively, introduction of the ketone moiety onto F-8 under similar conditions as described in Scheme D yields A-1, which is then used following the procedure as described in Scheme A to provide A-3. An alternative approach to convert F-2 to F-6 is the hydrolysis of ester F-2 to generate acid F-10, which is subsequently converted to the Weinreb amide F-11. Addition of a suitable Grignard reagent such as methylmagnesium chloride (in the case where R1=Me) to F-11 in THF generates F-6.

As illustrated in Scheme G, alkylation of 5-methyl-2-(methylthio)pyrido[2,3-d] pyrimidin-7(8H)-one G-1 (purchased or synthesized in a manner similar to that described by VanderWel, S. N. et al.,J. Med. Chem.2005, 48, 2371-2387) with a compound R3-X such as an alkyl halide or mesylate (i.e., methanesulfonate) in the presence of a base, such as 2-tert-butyl-1,1,3,3-tetramethylguanidine, yields a mixture of positional isomers 7-O— and 8-N-alkyl pyrido[2,3-d]pyrimidines G-2 and F-7, respectively, which are separated to provide F-7 that can be used as illustrated in Scheme F to obtain E-6.

As illustrated in Scheme H, amidation/cyclization of 1-[4-amino-2-(methylthio)pyrimidin-5-yl]ethan-1-one H-1 with a diketene precursor (i.e., 2,2,6-trimethyl-4H-1,3-dioxin-4-one) with or without solvents, such as toluene, yields methylthiopyrimidine H-2. Oxidation of the thiomethyl group of H-2 under standard conditions (vide supra), followed by SNAr reaction with various substituted amines R4—NH2under basic conditions, affords H-4. A standard SN2 reaction between H-4 and R3—X (e.g. alkyl halides) under basic conditions, using a base such as NaH, affords a mixture of 7-O— and 8-N-alkyl pyrido[2,3-d]pyrimidines H-5 and E-6 (a compound of A-3 wherein R2is CH3), respectively. Separation of these positional isomers provides E-6 that can be used as discussed herein.

As illustrated in Scheme I, to improve the solubility and enable subsequent transformations, H-3 was subjected to an SNAr reaction with various alkyl thiols R′—SH wherein R′ is an alkyl having at least 4 carbons (e.g., decylthiol) under basic conditions, such as with triethylamine and THF as solvent, to generate I-1. A photo-catalyzed regioselective N-alkylation of I-1, using various carboxylic acids R3—CO2H, yields the pyridopyrimidine 1-2. This reaction may be carried out using bis(acetyloxy)(2,4,6-trimethylphenyl)-λ3-iodane as oxidant and (2,2′-bipyridine-κ2N1,N1){bis[3,5-difluoro-2-(5-fluoropyridin-2-yl)phenyl]}iridium hexafluorophosphate as catalyst in dichloromethane. Oxidation of the thiomethyl group at C(2) under the standard conditions described above generates 1-3. SNAr reaction of 1-3 with various substituted amines R4—NH2under standard conditions yields E-6.

As illustrated in Scheme J, treatment of the commercially available 4-chloro-2-(methylthio)pyrimidine J-1 with a base, such as lithium diisopropylamide (LDA) in a suitable solvent such as THF, followed by the addition of a suitably substituted aldehyde R1CHO, provides the alcohol J-2. Oxidation of the alcohol J-2 under standard conditions, such as with manganese(IV) oxide in chloroform, gives the ketone J-3. SNAr reaction of J-3 with various substituted amines R3—NH2under basic conditions provides F-6, which can provide, e.g., E-6, as illustrated in Scheme F.

As illustrated in Scheme K, SNAr reaction of 1-(4,6-dichloropyridin-3-yl)ethan-1-one K-1 (purchased or synthesized in a manner similar to that described by McCoull, W. et al.,J. Med. Chem.2017, 60, 3187-3197) at the C-4 position with various substituted amines R3—NH2under basic conditions yields K-2. Amidation/cyclization of K-2 with a diketene precursor (e.g., 2,2,6-trimethyl-4H-1,3-dioxin-4-one) yields methyl ketone K-3. A standard transition metal-catalyzed C—N coupling reaction of K-3 with various amines R4—NH2in a suitable solvent, such as toluene or THF, yields 1,6-naphthyridin-2(1H)-one K-4.

As evident to someone skilled in the art, the methods described in Schemes E through K for introduction of the R3-substituent allows for the introduction of a wide variety of R3-substituents including (but not limited to) alkyl, cycloalkyl, and heterocycloalkyl groups. This may be accomplished simply by using the appropriately substituted amine reagent (Schemes E, F, J), halide reagent (Schemes G, H), or carboxylic acid reagent (Scheme I).

As illustrated in Scheme L, SNAr reaction of the commercially available methyl 4,6-dichloronicotinate L-1 with various substituted amines R3—NH2under basic conditions yields L-2. The transformation of the ester functionality of L-2 to the corresponding ketone group was accomplished using standard methods known in the art (like those described in Scheme F) to afford ketone L-3. A cyclocondensation of L-3 using either standard Horner-Wadsworth-Emmons conditions or ethyl acetate and a suitable base such as sodium bis(trimethylsilyl)amide yields naphthyridin-2(1H)-one L-4. A standard transitional metal-catalyzed C—N coupling reaction of L-4 with various substituted amines R4—NH2under basic conditions affords L-5. Following bromination of L-5 in at the C(6) position, the ketone moiety is introduced by treatment with an appropriately substituted vinyl stannane or alkoxy vinyl ether under standard cross-coupling reaction conditions followed by acid-mediated hydrolysis to yield aminopyridine L-7.

EXAMPLES

Experimental Procedures

The following illustrate the synthesis of various compounds of the present invention. Additional compounds within the scope of this invention may be prepared using the methods illustrated in these Examples, either alone or in combination with techniques generally known in the art.

Experiments were generally carried out under inert atmosphere (nitrogen or argon), particularly in cases where oxygen- or moisture-sensitive reagents or intermediates were employed. Commercial solvents and reagents were generally used without further purification. Anhydrous solvents were employed where appropriate, generally AcroSeal® products from Acros Organics, Aldrich® Sure/Seal™ from Sigma-Aldrich, or DriSolv® products from EMD Chemicals. In other cases, commercial solvents were passed through columns packed with 4 Å molecular sieves, until the following QC standards for water were attained: a) <100 ppm for dichloromethane, toluene, N,N-dimethylformamide, and tetrahydrofuran; b) <180 ppm for methanol, ethanol, 1,4-dioxane, and diisopropylamine. For very sensitive reactions, solvents were further treated with metallic sodium, calcium hydride, or molecular sieves, and distilled just prior to use. Products were generally dried under vacuum before being carried on to further reactions or submitted for biological testing. Mass spectrometry data is reported from either liquid chromatography-mass spectrometry (LCMS), atmospheric pressure chemical ionization (APCI) or gas chromatography-mass spectrometry (GCMS) instrumentation. Chemical shifts for nuclear magnetic resonance (NMR) data are expressed in parts per million (ppm, δ) referenced to residual peaks from the deuterated solvents employed (chloroform, 7.26 ppm; CD2HOD, 3.31 ppm; acetonitrile-d2, 1.94 ppm; dimethyl sulfoxide-d5, 2.50 ppm; DHO, 4.79 ppm). In some examples, chiral separations were carried out to separate enantiomers of certain compounds of the invention (in some examples, the separated enantiomers are designated as ENT-1 and ENT-2, according to their order of elution). In some examples, the optical rotation of an enantiomer was measured using a polarimeter. According to its observed rotation data (or its specific rotation data), an enantiomer with a clockwise rotation was designated as the (+)-enantiomer and an enantiomer with a counter-clockwise rotation was designated as the (−)-enantiomer. Similarly, in some examples separations were carried out to separate diastereomers of certain compounds of the invention; in some examples, the separated diastereomers are designated as DIAST-1 and DIAST-2, according to their order of elution. Racemic compounds are indicated either by the absence of drawn or described stereochemistry, or by the presence of (+/−) adjacent to the structure; in this latter case, the indicated stereochemistry represents just one of the two enantiomers that make up the racemic mixture.

Reactions proceeding through detectable intermediates were generally followed by LCMS, and allowed to proceed to full conversion prior to addition of subsequent reagents. For syntheses referencing procedures in other Examples or Methods, reaction conditions (reaction time and temperature) may vary. In general, reactions were followed by thin-layer chromatography or mass spectrometry, and subjected to work-up when appropriate. Purifications may vary between experiments: in general, solvents and the solvent ratios used for eluents/gradients were chosen to provide appropriate Rfs or retention times. All starting materials in these Preparations and Examples are either commercially available or can be prepared by methods known in the art or as described herein.

The compounds and intermediates described below were named using the naming convention provided with ACD/ChemSketch 2017.2.1, File Version N40E41, Build 96719 (Advanced Chemistry Development, Inc., Toronto, Ontario, Canada). The naming convention provided with ACD/ChemSketch 2017.2.1 is well known by those skilled in the art and it is believed that the naming convention provided with ACD/ChemSketch 2017.2.1 generally comports with the IUPAC (International Union for Pure and Applied Chemistry) recommendations on Nomenclature of Organic Chemistry and the CAS Index rules.

The terms “concentrated”, “evaporated”, and “concentrated in vacuo” refer to the removal of solvent at reduced pressure on a rotary evaporator with a bath temperature less than 60□C. The abbreviation “min” and “h” stand for “minutes” and “hours” respectively. The term “TLC” refers to thin layer chromatography, “room temperature or ambient temperature” means a temperature between 18° C. to 25° C., “LCMS” refers to liquid chromatography-mass spectrometry, “UPLC” refers to ultra performance liquid chromatography and “HPLC” refers to high pressure liquid chromatography.

Hydrogenation may be performed in a Parr Shaker under pressurized hydrogen gas, or in Thales-nano H-Cube flow hydrogenation apparatus at full hydrogen and a flow rate between 1-2 mL/min at specified temperature.

HPLC, UPLC, LCMS, and SFC retention times were measured using the methods noted in the procedures.

To an ice-cooled solution of C3 (1.70 g, 4.49 mmol) and ethyl acetate (1.39 g, 15.8 mmol) in tetrahydrofuran (20 mL) was added lithium bis(trimethylsilyl)amide (1 M solution; 13.5 mL, 13.5 mmol) in a portion-wise manner, at a rate of 0.5 mL every 10 seconds. The reaction mixture was stirred under ice-cooling for 30 minutes, and then at 40° C. for approximately 1 hour, whereupon it was diluted with aqueous ammonium chloride solution (5 mL), and combined with a similar reaction carried out using C3 (100 mg, 0.264 mmol). After the resulting mixture had been partitioned between ethyl acetate (30 mL) and saturated aqueous sodium chloride solution (20 mL), the aqueous layer was extracted with ethyl acetate (2×10 mL), and the combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via chromatography on silica gel (Gradient: 0% to 30% ethyl acetate in dichloromethane) to provide C4 as a light yellow solid. Combined yield: 1.65 g, 4.10 mmol, 86%. LCMS m/z 402.9 [M+H]+.

To a 0° C. solution of C7 (100 mg, 0.225 mmol) in tetrahydrofuran (8 mL) was added potassium peroxymonosulfate (Oxone®; 207 mg, 0.337 mmol), followed by water (4 mL). The reaction mixture was stirred at room temperature (10° C.) for 1 hour, whereupon it was partitioned between ethyl acetate (15 mL) and saturated aqueous sodium chloride solution (5 mL). The aqueous layer was extracted with ethyl acetate (2×5 mL), and the combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo, providing P2 (120 mg) as a light yellow solid. This material was used directly in subsequent chemistry.

A sample of P3 (30 mg) was dissolved in diethyl ether (2.0 mL) and treated with heptane (2.0 mL); the mixture was allowed to sit over a weekend in an unsealed vessel. One of the resulting crystals was used for X-ray structural determination (see below).

Single Crystal X-Ray Analysis

Data collection was performed on a Bruker D8 Quest diffractometer at room temperature. Data collection consisted of omega and phi scans.

The structure was solved by intrinsic phasing using SHELX software suite in the monoclinic space group P21. The structure was subsequently refined by the full-matrix least squares method. All non-hydrogen atoms were found and refined using anisotropic displacement parameters.

The hydrogen atoms were placed in calculated positions and were allowed to ride on their carrier atoms. The final refinement included isotropic displacement parameters for all hydrogen atoms.

Analysis of the absolute structure using likelihood methods (Hooft, 2008) was performed using PLATON (Spek). The results indicate that the absolute structure has been correctly assigned. The method calculates that the probability that the structure is correctly assigned is 100%. The Hooft parameter is reported as 0.018 with an esd of (8) and the Parsons parameter is reported as 0.024 with an esd of (9). The asymmetric unit contains two molecules of P3, and the absolute configuration was confirmed for both of these.

The final R-index was 2.8%. A final difference Fourier revealed no missing or misplaced electron density.

Pertinent crystal, data collection and refinement information is summarized in Table A. Atomic coordinates, bond lengths, bond angles, and displacement parameters are listed in Tables B-D.

Software and References

TABLE CBond lengths [Å] and angles [°] for P3.Br(1)—C(7)1.891(4)Br(2)—C(21)1.895(4)Cl(1)—C(2)1.731(5)Cl(2)—C(16)1.737(5)N(1)—C(2)1.329(7)N(1)—C(1)1.330(7)N(2)—C(2)1.306(5)N(2)—C(3)1.347(5)N(3)—C(3)1.385(4)N(3)—C(8)1.402(5)N(3)—C(9)1.490(5)N(4)—C(16)1.317(6)N(4)—C(15)1.322(6)N(5)—C(16)1.320(5)N(5)—C(17)1.342(5)N(6)—C(17)1.377(4)N(6)—C(22)1.388(5)N(6)—C(23)1.497(5)O(1)—C(8)1.216(5)O(2)—C(22)1.220(5)C(1)—C(4)1.386(6)C(1)—H(1)0.9300C(3)—C(4)1.404(6)C(4)—C(5)1.441(6)C(5)—C(7)1.346(6)C(5)—C(6)1.498(7)C(6)—H(6A)0.9600C(6)—H(6B)0.9600C(6)—H(6C)0.9600C(7)—C(8)1.460(6)C(9)—C(10)1.534(6)C(9)—C(13)1.555(6)C(9)—H(9)0.9800C(10)—C(11)1.521(7)C(10)—H(10A)0.9700C(10)—H(10B)0.9700C(11)—C(12)1.512(7)C(11)—H(11A)0.9700C(11)—H(11B)0.9700C(12)—C(13)1.522(6)C(12)—H(12A)0.9700C(12)—H(12B)0.9700C(13)—C(14)1.509(7)C(13)—H(13)0.9800C(14)—H(14A)0.9600C(14)—H(14B)0.9600C(14)—H(14C)0.9600C(15)—C(18)1.400(6)C(15)—H(15)0.9300C(17)—C(18)1.412(6)C(18)—C(19)1.440(6)C(19)—C(21)1.344(5)C(19)—C(20)1.492(7)C(20)—H(20A)0.9600C(20)—H(20B)0.9600C(20)—H(20C)0.9600C(21)—C(22)1.469(6)C(23)—C(27)1.532(7)C(23)—C(24)1.543(6)C(23)—H(23)0.9800C(24)—C(25)1.486(8)C(24)—H(24A)0.9700C(24)—H(24B)0.9700C(25)—C(26)1.485(9)C(25)—H(25A)0.9700C(25)—H(25B)0.9700C(26)—C(27)1.539(7)C(26)—H(26A)0.9700C(26)—H(26B)0.9700C(27)—C(28)1.496(7)C(27)—H(27)0.9800C(28)—H(28A)0.9600C(28)—H(28B)0.9600C(28)—H(28C)0.9600C(2)—N(1)—C(1)113.8(4)C(2)—N(2)—C(3)115.8(4)C(3)—N(3)—C(8)120.4(3)C(3)—N(3)—C(9)119.7(3)C(8)—N(3)—C(9)119.6(3)C(16)—N(4)—C(15)114.3(4)C(16)—N(5)—C(17)115.8(4)C(17)—N(6)—C(22)120.6(3)C(17)—N(6)—C(23)119.9(3)C(22)—N(6)—C(23)119.5(3)N(1)—C(1)—C(4)124.5(5)N(1)—C(1)—H(1)117.8C(4)—C(1)—H(1)117.8N(2)—C(2)—N(1)129.3(4)N(2)—C(2)—C1(1)115.5(4)N(1)—C(2)—C1(1)115.2(3)N(2)—C(3)—N(3)117.4(3)N(2)—C(3)—C(4)121.6(3)N(3)—C(3)—C(4)121.0(4)C(1)—C(4)—C(3)115.1(4)C(1)—C(4)—C(5)124.1(4)C(3)—C(4)—C(5)120.8(3)C(7)—C(5)—C(4)116.6(4)C(7)—C(5)—C(6)124.0(4)C(4)—C(5)—C(6)119.4(4)C(5)—C(6)—H(6A)109.5C(5)—C(6)—H(6B)109.5H(6A)—C(6)—H(6B)109.5C(5)—C(6)—H(6C)109.5H(6A)—C(6)—H(6C)109.5H(66)—C(6)—H(6C)109.5C(5)—C(7)—C(8)124.4(4)C(5)—C(7)—Br(1)122.6(3)C(8)—C(7)—Br(1)113.0(3)O(1)—C(8)—N(3)120.0(4)O(1)—C(8)—C(7)123.2(4)N(3)—C(8)—C(7)116.8(3)N(3)—C(9)—C(10)112.4(4)N(3)—C(9)—C(13)117.1(3)C(10)—C(9)—C(13)106.7(3)N(3)—C(9)—H(9)106.7C(10)—C(9)—H(9)106.7C(13)—C(9)—H(9)106.7C(11)—C(10)—C(9)104.6(4)C(11)—C(10)—H(10A)110.8C(9)—C(10)—H(10A)110.8C(11)—C(10)—H(10B)110.8C(9)—C(10)—H(10B)110.8H(10A)—C(10)—H(10B)108.9C(12)—C(11)—C(10)103.7(4)C(12)—C(11)—H(11A)111.0C(10)—C(11)—H(11A)111.0C(12)—C(11)—H(11B)111.0C(10)—C(11)—H(11B)111.0H(11A)—C(11)—H(11B)109.0C(11)—C(12)—C(13)104.4(4)C(11)—C(12)—H(12A)110.9C(13)—C(12)—H(12A)110.9C(11)—C(12)—H(12B)110.9C(13)—C(12)—H(12B)110.9H(12A)—C(12)—H(12B)108.9C(14)—C(13)—C(12)115.0(4)C(14)—C(13)—C(9)118.3(4)C(12)—C(13)—C(9)104.3(4)C(14)—C(13)—H(13)106.1C(12)—C(13)—H(13)106.1C(9)—C(13)—H(13)106.1C(13)—C(14)—H(14A)109.5C(13)—C(14)—H(14B)109.5H(14A)—C(14)—H(14B)109.5C(13)—C(14)—H(14C)109.5H(14A)—C(14)—H(14C)109.5H(14B)—C(14)—H(14C)109.5N(4)—C(15)—C(18)124.4(4)N(4)—C(15)—H(15)117.8C(18)—C(15)—H(15)117.8N(4)—C(16)—N(5)129.3(4)N(4)—C(16)—Cl(2)115.6(3)N(5)—C(16)—Cl(2)115.2(4)N(5)—C(17)—N(6)117.4(4)N(5)—C(17)—C(18)121.6(3)N(6)—C(17)—C(18)121.0(3)C(15)—C(18)—C(17)114.7(4)C(15)—C(18)—C(19)124.5(4)C(17)—C(18)—C(19)120.8(3)C(21)—C(19)—C(18)116.2(4)C(21)—C(19)—C(20)123.6(4)C(18)—C(19)—C(20)120.2(4)C(19)—C(20)—H(20A)109.5C(19)—C(20)—H(20B)109.5H(20A)—C(20)—H(20B)109.5C(19)—C(20)—H(20C)109.5H(20A)—C(20)—H(20C)109.5H(20B)—C(20)—H(20C)109.5C(19)—C(21)—C(22)124.4(4)C(19)—C(21)—Br(2)122.7(3)C(22)—C(21)—Br(2)112.9(3)O(2)—C(22)—N(6)120.8(4)O(2)—C(22)—C(21)122.4(4)N(6)—C(22)—C(21)116.8(3)N(6)—C(23)—C(27)116.1(3)N(6)—C(23)—C(24)113.3(4)C(27)—C(23)—C(24)105.5(3)N(6)—C(23)—H(23)107.2C(27)—C(23)—H(23)107.2C(24)—C(23)—H(23)107.2C(25)—C(24)—C(23)107.0(5)C(25)—C(24)—H(24A)110.3C(23)—C(24)—H(24A)110.3C(25)—C(24)—H(24B)110.3C(23)—C(24)—H(24B)110.3H(24A)—C(24)—H(24B)108.6C(26)—C(25)—C(24)108.0(4)C(26)—C(25)—H(25A)110.1C(24)—C(25)—H(25A)110.1C(26)—C(25)—H(25B)110.1C(24)—C(25)—H(25B)110.1H(25A)—C(25)—H(25B)108.4C(25)—C(26)—C(27)104.2(5)C(25)—C(26)—H(26A)110.9C(27)—C(26)—H(26A)110.9C(25)—C(26)—H(26B)110.9C(27)—C(26)—H(26B)110.9H(26A)—C(26)—H(26B)108.9C(28)—C(27)—C(23)117.0(5)C(28)—C(27)—C(26)114.3(6)C(23)—C(27)—C(26)105.4(4)C(28)—C(27)—H(27)106.5C(23)—C(27)—H(27)106.5C(26)—C(27)—H(27)106.5C(27)—C(28)—H(28A)109.5C(27)—C(28)—H(28B)109.5H(28A)—C(28)—H(28B)109.5C(27)—C(28)—H(28C)109.5H(28A)—C(28)—H(28C)109.5H(28B)—C(28)—H(28C)109.5

A mixture of C10 (177 g, 741 mmol) and 2,2,6-trimethyl-4H-1,3-dioxin-4-one (316 g, 2.22 mol) was stirred at 75° C. to 85° C. for 72 hours, whereupon toluene (354 g, 2 volumes) was added, and the resulting mixture was cooled to 15° C. to 30° C. Dichloromethane (2 volumes) was added, and the mixture was stirred at 15° C. to 30° C. for 30 to 40 minutes, whereupon it was treated with silica gel (354 g) and stirring was continued at 15° C. to 30° C. for 20 to 30 minutes. After this mixture had been filtered through a pad of silica gel (177 g), the filter pad was further eluted with a 1:1 mixture of propan-2-yl acetate and heptane (approximately 45 volumes), and the eluent was monitored by thin-layer chromatography (Eluent: 3:1 petroleum ether/heptane) until no further product P4 was detected. The appropriate eluates were combined and concentrated in vacuo, to 2 to 3 volumes. 2-Propanol (5 volumes) was then added, and the mixture was concentrated to 2 to 3 volumes; this process was repeated until the residual propan-2-yl acetate was ≥0.2% by GC analysis. The resulting mixture was cooled to −5° C. to 5° C. and stirred for 1 to 2 hours, whereupon it was filtered to provide P4 as a solid. Yield: 69.0 g, 226 mmol, 30%. Representative1H NMR (500 MHz, DMSO-d6) δ 8.86 (s, 1H), 7.84 (s, 1H), 5.31-5.20 (m, 1H), 2.43 (s, 3H), 2.36 (s, 3H), 2.16-2.04 (m, 2H), 2.00-1.84 (m, 4H), 1.70-1.58 (m, 2H).

Step 2. Synthesis of rac-(1S,2R,5R)-bicyclo[3.1.0]hexan-2-amine, hydrochloride salt (C23)

A mixture of C22, hydrochloride salt (800 mg, 3.58 mmol), palladium hydroxide on carbon (800 mg), and hydrogen chloride (4 M solution in ethyl acetate; 1.8 mL, 7.2 mmol) in methanol (15 mL) was degassed 3 times with hydrogen. The reaction mixture was then stirred under hydrogen (1 atmosphere) for 5 hours at 50° C., whereupon it was filtered; the filtrate was concentrated in vacuo to afford C23 as a white solid. Yield: 452 mg, 3.38 mmol, 94%.

Triethylamine (1.51 g, 14.9 mmol) was added drop-wise to a 0° C. solution of 5-bromo-2,4-dichloropyrimidine (850 mg, 3.73 mmol) and C23 (452 mg, 3.38 mmol) in acetonitrile (50 mL). The reaction mixture was allowed to warm to room temperature, and stirred at 20° C. for 18 hours, whereupon it was treated with aqueous ammonium chloride solution (30 mL) and extracted with ethyl acetate (2×50 mL). The combined organic layers were dried, filtered, concentrated in vacuo, and subjected to chromatography on silica gel (Gradient: 1% to 4% ethyl acetate in petroleum ether), providing C24 as a white solid. Yield: 790 mg, 2.74 mmol, 81%. LCMS m/z 289.6 (bromine-chlorine isotope pattern observed) [M+H]+.

Vapor diffusion of pentane into a dichloroethane solution of C26 provided crystals for the X-ray structure determination.

Single Crystal X-Ray Analysis

Data collection was performed on a Bruker Kappa APEX-II CCD diffractometer equipped with Mo Kαradiation (λ=0.71073 Å). A 0.313×0.155×0.117 mm piece of a colorless block was mounted on a CryoLoop with Paratone oil. Data were collected in a nitrogen gas stream at 100(2) K using ϕ and ω scans. The crystal-to-detector distance was 40 mm and exposure time was 30 seconds per frame using a scan width of 1.0°. Data collection was 99.9% complete to 25.00° in e. A total of 9647 reflections were collected covering the indices, −21<=h<=25, −5<=k<=5, −15<=/<=13. 2400 reflections were found to be symmetry independent, with an Rintof 0.0561. Indexing and unit cell refinement indicated a primitive, monoclinic lattice. The space group was found to be P21/c. The data were integrated using the Bruker SAINT software program and scaled using the SADABS software program. Solution by direct methods (SHELXT) produced a complete phasing model consistent with the proposed structure. All non-hydrogen atoms were refined anisotropically by full-matrix least-squares (SHELXL-2014; G. M. Sheldrick, SHELXTL Version 2014/7. http://shelx.uni-ac.gwdg.de/SHELX/index.php). All hydrogen atoms were placed using a riding model. Their positions were constrained relative to their parent atom using the appropriate HFIX command in SHELXL-2014. Crystallographic data are summarized in Table E. Atomic coordinates, bond lengths, bond angles, and displacement parameters are listed in Tables F-K.

TABLE FAtomic coordinates (×104) and equivalent isotropic displacementparameters (Å2× 103) for C26. U(eq) is defined as one-thirdof the trace of the orthogonalized Uijtensor.xyzU(eq)O(1)7454(1)1289(4)6754(2)44(1)O(2)7039(1)5049(4)5898(1)29(1)N(1)7846(1)5561(5)7148(2)42(1)C(7)7455(1)3761(6)6618(2)29(1)C(8)6549(1)3341(6)5343(2)33(1)C(9)6224(1)5088(5)4470(2)26(1)C(10)5705(1)6681(6)4620(2)33(1)C(11)5423(2)8381(6)3827(2)37(1)C(12)5665(2)8493(6)2874(2)34(1)C(13)6178(2)6908(6)2722(2)35(1)C(14)6459(2)5207(6)3512(2)32(1)F(1)8476(2)8644(8)8816(3)53(1)C(1)8433(5)4610(20)7822(7)37(2)C(2)9098(5)5300(20)7506(7)50(2)C(3)9531(4)4960(30)8517(7)74(3)C(4)9117(5)4990(30)9444(7)42(2)C(5)8476(4)5724(14)8928(5)34(1)C(6)7938(4)4967(16)9490(6)46(2)F(1B)8936(2)8411(8)7779(4)72(2)C(1B)8246(4)4797(19)8080(7)45(2)C(2B)8106(5)6190(20)9124(7)72(2)C(3B)8737(6)5890(30)9817(8)125(4)C(4B)9238(6)5150(30)9119(10)73(3)C(5B)8919(4)5541(14)8036(8)56(2)C(6B)9187(5)4170(20)7138(9)90(3)

TABLE GBond lengths [Å] and angles [°] for C26.O(1)—C(7)1.213(3)O(2)—C(7)1.349(3)O(2)—C(8)1.446(3)N(1)H(1A)0.8800N(1)—H(1B)0.8800N(1)—C(7)1.331(4)N(1)—C(1)1.497(10)N(1)—C(1B)1.426(9)C(8)—H(8A)0.9900C(8)—H(8B)0.9900C(8)—C(9)1.501(4)C(9)—C(10)1.380(4)C(9)—C(14)1.386(4)C(10)—H(10)0.9500C(10)—C(11)1.387(4)C(11)—H(11)0.9500C(11)—C(12)1.387(4)C(12)—H(12)0.9500C(12)—C(13)1.367(4)C(13)—H(13)0.9500C(13)—C(14)1.383(4)C(14)—H(14)0.9500F(1)—C(5)1.426(8)C(1)—H(1)1.0000C(1)—C(2)1.553(14)C(1)—C(5)1.510(11)C(2)—H(2A)0.9900C(2)—H(2B)0.9900C(2)—C(3)1.502(11)C(3)—H(3A)0.9900C(3)—H(3B)0.9900C(3)—C(4)1.566(12)C(4)—H(4A)0.9900C(4)—H(4B)0.9900C(4)—C(5)1.479(13)C(5)—C(6)1.475(11)C(6)—H(6A)0.9800C(6)—H(6B)0.9800C(6)—H(6C)0.9800F(1B)—C(5B)1.434(8)C(1B)—H(1BA)1.0000C(1B)—C(2B)1.562(12)C(1B)—C(5B)1.482(13)C(2B)—H(2BA)0.9900C(2B)—H(2BB)0.9900C(2B)—C(3B)1.519(13)C(3B)—H(3BA)0.9900C(3B)—H(3BB)0.9900C(3B)—C(4B)1.519(16)C(4B)—H(4BA)0.9900C(4B)—H(4BB)0.9900C(4B)—C(5B)1.479(14)C(5B)—C(6B)1.505(12)C(6B)—H(6BA)0.9800C(6B)—H(6BB)0.9800C(6B)—H(6BC)0.9800C(7)—O(2)—C(8)116.1(2)C(7)—N(1)—H(1A)119.6C(7)—N(1)—H(1B)119.2C(7)—N(1)—C(1)120.9(5)C(7)—N(1)—C(1B)121.6(4)C(1)—N(1)—H(1A)119.6C(1B)—N(1)—H(1B)119.2O(1)—C(7)—O(2)123.0(3)O(1)—C(7)—N(1)126.1(3)N(1)—C(7)—O(2)110.9(2)O(2)—C(8)—H(8A)110.5O(2)—C(8)—H(8B)110.5O(2)—C(8)—C(9)106.1(2)H(8A)—C(8)—H(8B)108.7C(9)—C(8)—H(8A)110.5C(9)—C(8)—H(8B)110.5C(10)—C(9)—C(8)120.9(2)C(10)—C(9)—C(14)118.9(3)C(14)—C(9)—C(8)120.2(3)C(9)—C(10)—H(10)119.7C(9)—C(10)—C(11)120.7(3)C(11)—C(10)—H(10)119.7C(10)—C(11)—H(11)120.1C(10)—C(11)—C(12)119.8(3)C(12)—C(11)—H(11)120.1C(11)—C(12)—H(12)120.2C(13)—C(12)—C(11)119.7(3)C(13)—C(12)—H(12)120.2C(12)—C(13)—H(13)119.7C(12)—C(13)—C(14)120.6(3)C(14)—C(13)—H(13)119.7C(9)—C(14)—H(14)119.8C(13)—C(14)—C(9)120.3(3)C(13)—C(14)—H(14)119.8N(1)—C(1)—H(1)107.0N(1)—C(1)—C(2)120.1(7)N(1)—C(1)—C(5)112.4(7)C(2)—C(1)—H(1)107.0C(5)—C(1)—H(1)107.0C(5)—C(1)—C(2)102.7(8)C(1)—C(2)—H(2A)111.1C(1)—C(2)—H(2B)111.1H(2A)—C(2)—H(2B)109.1C(3)—C(2)—C(1)103.2(7)C(3)—C(2)—H(2A)111.1C(3)—C(2)—H(2B)111.1C(2)—C(3)—H(3A)110.0C(2)—C(3)—H(3B)110.0C(2)—C(3)—C(4)108.3(7)H(3A)—C(3)—H(3B)108.4C(4)—C(3)—H(3A)110.0C(4)—C(3)—H(3B)110.0C(3)—C(4)—H(4A)111.0C(3)—C(4)—H(4B)111.0H(4A)—C(4)—H(4B)109.0C(5)—C(4)—C(3)103.6(7)C(5)—C(4)—H(4A)111.0C(5)—C(4)—H(4B)111.0F(1)—C(5)—C(1)105.2(6)F(1)—C(5)—C(4)105.8(7)F(1)—C(5)—C(6)107.8(7)C(4)—C(5)—C(1)106.2(7)C(6)—C(5)—C(1)114.4(7)C(6)—C(5)—C(4)116.6(6)C(5)—C(6)—H(6A)109.5C(5)—C(6)—H(6B)109.5C(5)—C(6)—H(6C)109.5H(6A)—C(6)—H(6B)109.5H(6A)—C(6)—H(6C)109.5H(6B)—C(6)—H(6C)109.5N(1)—C(1B)—H(1BA)108.3N(1)—C(1B)—C(2B)116.7(7)N(1)—C(1B)—C(5B)112.3(7)C(2B)—C(1B)—H(1BA)108.3C(5B)—C(1B)—H(1BA)108.3C(5B)—C(1B)—C(2B)102.5(8)C(1B)—C(2B)—H(2BA)111.3C(1B)—C(2B)—H(2BB)111.3H(2BA)—C(2B)—H(2BB)109.2C(3B)—C(2B)—C(1B)102.2(9)C(3B)—C(26)—H(2BA)111.3C(3B)—C(2B)—H(2BB)111.3C(2B)—C(3B)—H(3BA)110.1C(2B)—C(3B)—H(3BB)110.1H(3BA)—C(3B)—H(3BB)108.4C(4B)—C(3B)—C(2B)108.0(8)C(4B)—C(3B)—H(3BA)110.1C(4B)—C(3B)—H(3BB)110.1C(3B)—C(4B)—H(4BA)110.8C(3B)—C(4B)—H(4BB)110.8H(4BA)—C(4B)—H(4BB)108.9C(5B)—C(4B)—C(3B)104.6(9)C(5B)—C(4B)—H(4BA)110.8C(5B)—C(4B)—H(4BB)110.8F(1B)—C(5B)—C(1B)107.3(6)F(1B)—C(5B)—C(4B)108.7(8)F(1B)—C(5B)—C(6B)103.5(8)C(1B)—C(5B)—C(6B)112.4(8)C(4B)—C(5B)—C(1B)105.2(9)C(4B)—C(5B)—C(6B)119.3(8)C(5B)—C(6B)—H(6BA)109.5C(5B)—C(6B)—H(6BB)109.5C(5B)—C(6B)—H(6BC)109.5H(6BA)—C(6B)—H(6BB)109.5H(6BA)—C(6B)—H(6BC)109.5H(6BB)—C(6B)—H(6BC)109.5

Symmetry transformations used to generate equivalent atoms:

Step 3. Synthesis of rac-(1R,2S)-2-fluoro-2-methylcyclopentanamine, Hydrochloride Salt (C27)

A mixture of C26 (281 mg, 1.12 mmol), 20% palladium hydroxide on carbon (50 mg), and hydrogen chloride (2 M solution in methanol; 0.671 mL, 1.34 mmol) was stirred under a balloon of hydrogen overnight, whereupon it was filtered through diatomaceous earth. The filtrate was resubjected to the reaction conditions overnight, and again filtered through diatomaceous earth. Concentration of the filtrate provided C27 as a pale yellow solid (189 mg). By1H NMR analysis, this material was not entirely pure; a portion of it was progressed directly to the following step.1H NMR (400 MHz, DMSO-d6), characteristic peaks: δ 2.12-1.55 (m, 6H), 1.50 (d, JHF=22.0 Hz, 3H).

A solution of 3-chloroperoxybenzoic acid (16.7 g, 96.8 mmol) in dichloromethane (300 mL) was added over 30 minutes, in a drop-wise manner, to a −5° C. solution of C33 (14.0 g, 44.1 mmol) in dichloromethane (300 mL). After the reaction mixture had been stirred at 15° C. for 16 hours, it was diluted with saturated aqueous sodium sulfite solution (6 mL), followed by saturated aqueous sodium carbonate solution (35 mL). The resulting mixture was extracted with dichloromethane (2×50 mL), and the combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. By1H NMR analysis, the reaction was incomplete, so this material was dissolved in dichloromethane (150 mL), cooled to −5° C., and again treated drop-wise with a solution of 3-chloroperoxybenzoic acid (3.0 g, 17 mmol) in dichloromethane (10 mL). This reaction mixture was stirred at 15° C. for 3 hours, whereupon it was treated with saturated aqueous sodium sulfite solution (2 mL), diluted with saturated aqueous sodium carbonate solution (20 mL), and extracted with dichloromethane (2×30 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo to give P12 as a yellow solid (15 g). This material was combined with the product from a similar reaction carried out using C33 (1.47 g, 4.63 mmol), mixed with dichloromethane (60 mL) and petroleum ether (400 mL), and stirred for 40 minutes. Filtration provided P12 as a yellow solid. Combined yield: 14.3 g, 40.9 mmol, 84%. LCMS m/z 350.3 [M+H]+.1H NMR (400 MHz, chloroform-d) δ 9.10 (s, 1H), 5.96-5.85 (m, 1H), 3.39 (s, 3H), 2.57 (s, 3H), 2.46 (s, 3H), 2.33-2.21 (m, 2H), 2.21-2.10 (m, 2H), 2.01-1.90 (m, 2H), 1.77-1.65 (m, 2H).

Alternate Preparation of P12

A mixture of C32 (172.7 g, 487.5 mmol), butyl ethenyl ether (146.0 g, 1.458 mol), N,N-diisopropylethylamine (121 mL, 695 mmol), and {bis[2-(diphenylphosphino)phenyl]ether}palladium(II) dichloride [Pd(DPEPhos)Cl2; 6.98 g, 9.75 mmol] in n-butanol (1 L) was degassed for 15 minutes with nitrogen, and then heated to an internal temperature of 89° C. The reaction mixture was stirred overnight, using a mechanical stirrer, whereupon aqueous sodium carbonate solution (5%; 1 L) was added. The organic layer was concentrated under reduced pressure, using a water bath at 50° C., to remove the n-butanol, and the resulting solid was dissolved in ethyl acetate (1 L). Activated charcoal (60 g) was added, and the mixture was stirred for 10 minutes before being filtered through a pad of diatomaceous earth. The filter pad was washed with ethyl acetate, and the combined filtrates were treated with SiliCycle SiliaMetS® thiol metal scavenger (45.0 g), stirred at room temperature for 30 minutes at room temperature, and filtered. The filter pad was washed with ethyl acetate, and the combined filtrates were again treated with SiliCycle SiliaMetS® thiol metal scavenger (22.5 g), stirred at room temperature for 30 minutes, and filtered. The filter pad was washed with ethyl acetate, and the combined filtrates were concentrated in vacuo to afford a solid, which was dissolved in ethyl acetate (1 L) and treated with hydrochloric acid (6 M; 90 mL). After this reaction mixture had been stirred at room temperature for 2 hours, it was filtered, and the collected solids were washed with a 1:1 mixture of tert-butyl methyl ether and ethyl acetate to provide C33, hydrochloride salt as a solid (132 g). The filtrate was concentrated to dryness under reduced pressure; the residue was dissolved in a mixture of tert-butyl methyl ether and ethyl acetate (1:1, 300 mL), and slurried for 30 minutes. This mixture was then filtered, and the collected solids were washed with a 1:1 mixture of tert-butyl methyl ether and ethyl acetate, providing additional C33, hydrochloride salt (31 g) as an off-white solid. Combined yield: 163 g, 460 mmol, 94%. LCMS m/z 318.2 [M+H]+.1H NMR (400 MHz, CDCl3) 8.95 (s, 1H), 8.33 (br s, 1H), 5.94-5.83 (m, 1H), 2.79 (s, 3H), 2.55 (s, 3H), 2.41 (s, 3H), 2.34-2.23 (m, 2H), 2.14-2.02 (m, 2H), 1.99-1.88 (m, 2H), 1.78-1.66 (m, 2H).

A solution of C33, hydrochloride salt (154 g, 435 mmol) in tetrahydrofuran (1.8 L) was diluted with water (500 mL), treated with potassium phosphate (40.2 g, 189 mmol), and cooled to 15° C. under mechanical stirring. Potassium peroxymonosulfate (Oxone®; 402.0 g, 654 mmol) was then slowly added into the stirring solution over several minutes. The ice bath was sporadically applied thereafter to maintain the internal temperature below 25° C., and stirring was continued for 2 additional hours. LCMS analysis at this point indicated conversion to the product: LCMS m/z 350.1 [M+H]+. The reaction mixture was then filtered, and the collected solid was washed with ethyl acetate. The aqueous layer of the combined filtrates was extracted with ethyl acetate, and the combined organic layers were washed twice with saturated aqueous sodium chloride solution, dried over magnesium sulfate, filtered, and concentrated in vacuo. The residue was slurried in a mixture of ethyl acetate in heptane (5%; 1 L) for 1 hour; the solid was collected via filtration and washed with 5% ethyl acetate in heptane, providing P12 (135 g) as a pale yellow solid. Concentration of the filtrate under reduced pressure provided a residue, which was slurried for 4 hours in a mixture of ethyl acetate in heptane (5%; 250 mL), whereupon the solid was collected via filtration and washed with 5% ethyl acetate in heptane to afford additional P12 (4.0 g) as a white solid. Combined yield: 139 g, 398 mmol, 91%.1H NMR (400 MHz, CDCl3) 9.11 (s, 1H), 5.96-5.85 (m, 1H), 3.39 (s, 3H), 2.57 (s, 3H), 2.46 (s, 3H), 2.33-2.22 (m, 2H), 2.22-2.10 (m, 2H), 2.01-1.91 (m, 2H), 1.78-1.65 (m, 2H).

Potassium peroxymonosulfate (Oxone®; 128 g, 208 mmol) was added to a suspension of C34 (17.2 g, 69.0 mmol) in a mixture of tetrahydrofuran (800 mL) and water (160 mL) at room temperature (20° C.). The reaction mixture was stirred at 25° C. for 27 hours, whereupon it was diluted with water (800 mL), stirred at room temperature (15° C.) for 2 hours, and filtered. The collected solid was washed sequentially with water (300 mL) and tert-butyl methyl ether (100 mL), then mixed with water (300 mL), stirred at room temperature (20° C.) for 1 hour, and filtered. The filter cake was washed with water (100 mL) and combined with the product of a similar reaction carried out using C34 (2.10 g, 8.42 mmol). This material was again mixed with water (150 mL), stirred at room temperature (20° C.) for 1 hour, and filtered. This filter cake was washed with water (80 mL) to provide C35 as a white solid. Combined yield: 9.0 g, 32.0 mmol, 41%. LCMS m/z 282.1 [M+H]+.1H NMR (400 MHz, DMSO-d6) δ 13.31 (br s, 1H), 9.39 (s, 1H), 3.43 (s, 3H), 2.46 (s, 3H), 2.41 (s, 3H).

A freshly opened bottle of N,N-dimethylformamide was sparged with nitrogen for approximately 15 minutes. A mixture of P4 (63.0 g, 207 mmol), (3S,4R)-4-aminotetrahydro-2H-pyran-3-ol (29.1 g, 248 mmol) and lithium tert-butoxide (19.9 g, 249 mmol) was dissolved in the sparged N,N-dimethylformamide (300 mL), and the flask was purged under gentle nitrogen pressure for approximately 15 minutes.

Further purification was carried out as follows. A solution of 5 (185 g, 480 mmol) in dichloromethane (approximately 750 mL) was prepared via application of minimal heat until 5 was in solution. SiliaMetS Thiol (SH) (Silicycle; 18.3 g) was added, and the resulting mixture was stirred at a gentle reflux for 30 minutes, whereupon it was cooled in an ice bath for 5 minutes, and filtered through a 1 cm pad of diatomaceous earth, followed by a dichloromethane (approximately 250 mL) rinse of the filter pad. The combined filtrates were distilled at atmospheric pressure to remove dichloromethane (approximately 250 mL). tert-Butyl methyl ether (500 mL) and seed crystals of 5 (approximately 100 mg; see the origin of these crystals below) were added, and additional solvent (approximately 250 mL, boiling point approximately 45° C.) was removed by distillation. tert-Butyl methyl ether (500 mL) was again added, and the mixture was stirred, resulting in precipitation of solid; distillation was continued until a total of approximately 1.3 L had been collected, and the boiling point of the distillate was 50.6° C. At this point, the mixture was allowed to cool to room temperature with stirring, whereupon the solid was collected by filtration and rinsed with tert-butyl methyl ether (2×100 mL), affording 5 as a yellow solid (163 g, 423 mmol, 88% for the purification).

Alternative reaction conditions to obtain 5 from P4 and (3S,4R)-4-aminotetrahydro-2H-pyran-3-ol include using Pd(OAc)2of (AllylPdCl)2and t-BuBrettPhos as the catalyst/ligand; using solvents including isopropyl acetate, methyl ethyl ketone, toluene, THF, and 2-methyltetrhydrofuran that preferably contains THF [up to approximately 20% of THF]; and using another base including NaOt-Bu, KOt-Bu, KOt-Amyl, K3PO4, and Cs2CO3. Alternative workup conditions include quenching the reaction with aqueous ammonium chloride and washing the aqueous layer with organic solvent consistent with the reaction solvent. Purification of 5 can be accomplished with an acid/base workup followed by a thiol-silica gel plug. Water is added to the combined organic layers, and the pH is adjusted to about 6 by addition of 1 M hydrochloric acid. tert-Butyl methyl ether is used as a wash. The pH can be adjusted to about 5 with NaOH and K3PO4. Example 5 is extracted with an organic solvent like dichloromethane and purified similarly as discussed above. A short chain alcohol, e.g., C1-3alcohol, can be included in the organic layer to elute 5 from the thiol-silica gel plug. Any color present could be removed by standard procedures before crystallization from a short chain alcohol.

Generation of Seed Crystals of 5

A slurry of 5 (40 g) in ethanol (235 mL) was heated at reflux until a solution was obtained. Water (600 mL) was added to the hot solution in a drop-wise manner over 35 minutes, and solvent (an ethanol/water azeotrope) was collected using a short-path distillation head while a vacuum of approximately 450 mbar was maintained. Heating was continued for 45 minutes after completion of the water addition; during this time, approximately 125 mL of solvent were collected. The heat was then turned off, and the mixture was allowed to stir and cool to room temperature overnight. Filtration, followed by washing of the filter cake with water, provided 5 (37.5 g) as a light beige solid, which was shown to be crystalline via powder X-ray diffraction analysis; a portion of this material was used as the seed crystals employed above.

Generation of a Crystal of 5 for X-Ray Structural Determination

Single Crystal X-Ray Analysis

Data collection was performed on a Bruker D8 Venture diffractometer at room temperature. Data collection consisted of omega and phi scans.

The structure was solved by intrinsic phasing using SHELX software suite in the monoclinic space group P21. The structure was subsequently refined by the full-matrix least squares method. All non-hydrogen atoms were found and refined using anisotropic displacement parameters.

The disordered positions at C17-C15 were noted but not treated with a disorder model. The hydrogen atoms located on nitrogen and oxygen were found from the Fourier difference map and refined with distances restrained. The remaining hydrogen atoms were placed in calculated positions and were allowed to ride on their carrier atoms. The final refinement included isotropic displacement parameters for all hydrogen atoms.

Analysis of the absolute structure using likelihood methods (Hooft, 2008) was performed using PLATON (Spek). An attempt was made to determine the absolute configuration directly from the X-ray diffraction data by the method of Hooft and also with the Parsons method. The final refined Hooft parameter and Parsons parameter were both given as 0.12 with an esd of 0.06. This value indicates that the stereochemistry of 5 depicted in the scheme above represents the absolute configuration.

The final R-index was 4.2%. A final difference Fourier revealed no missing or misplaced electron density.

Pertinent crystal, data collection and refinement information is summarized in Table L. Atomic coordinates, bond lengths, bond angles, and displacement parameters are listed in Tables M-P.

TABLE MAtomic coordinates (×104) and equivalent isotropic displacementparameters (Å2× 103) for 5. U(eq) is defined as one-third ofthe trace of the orthogonalized Uijtensor.xyzU(eq)N(1)9697(2)4394(3)4774(2)53(1)N(2)9158(2)4372(3)6695(2)46(1)N(3)4911(2)5202(2)5519(2)36(1)O(1)8944(2)6876(3)3237(2)64(1)O(2)10612(3)4542(4)1214(2)93(1)O(3)3389(4)6836(4)8920(4)115(1)O(4)2691(2)5473(3)6001(2)68(1)C(1)9889(3)5800(3)2945(3)51(1)C(2)9793(4)5677(5)1581(3)74(1)C(3)10188(5)3206(6)1636(4)92(1)C(4)10309(4)3151(5)2992(4)72(1)C(5)9482(3)4379(3)3471(2)45(1)C(6)8697(2)4556(3)5507(2)40(1)C(7)7301(2)4863(3)5087(2)39(1)C(8)6338(2)4995(2)5896(2)34(1)C(9)6823(2)4904(2)7148(2)37(1)C(10)8236(3)4569(3)7462(2)44(1)C(11)5869(3)5132(3)8017(2)41(1)C(12)6412(3)5109(5)9343(2)65(1)C(13)4512(3)5366(3)7620(2)43(1)C(14)3436(3)5668(4)8465(2)55(1)C(15)2508(4)4508(6)8742(3)84(1)C(16)3955(3)5346(3)6343(2)44(1)C(17)4324(3)5237(3)4226(2)41(1)C(18)4829(4)6495(3)3493(2)56(1)C(19)4950(7)5850(5)2262(3)105(2)C(20)4370(5)4405(5)2216(3)80(1)C(21)4515(3)3862(3)3503(3)49(1)

TABLE NBond lengths [Å] and angles [°] for 5.N(1)—C(6)1.353(3)N(1)—C(5)1.446(3)N(1)—H(1X)0.93(2)N(2)—C(10)1.326(3)N(2)—C(6)1.357(3)N(3)—C(16)1.393(3)N(3)—C(8)1.397(3)N(3)—C(17)1.483(3)O(1)—C(1)1.416(4)O(1)—H(1Y)0.98(2)O(2)—C(3)1.404(6)O(2)—C(2)1.408(5)O(3)—C(14)1.199(4)O(4)—C(16)1.233(3)C(1)—C(5)1.514(4)C(1)—C(2)1.522(4)C(1)—H(1A)0.9800C(2)—H(2A)0.9700C(2)—H(2B)0.9700C(3)—C(4)1.507(6)C(3)—H(3A)0.9700C(3)—H(3B)0.9700C(4)—C(5)1.526(4)C(4)—H(4A)0.9700C(4)—H(4B)0.9700C(5)—H(5)0.9800C(6)—C(7)1.395(3)C(7)—C(8)1.384(3)C(7)—H(7)0.9300C(8)—C(9)1.420(3)C(9)—C(10)1.396(3)C(9)—C(11)1.439(3)C(10)—H(10)0.9300C(11)—C(13)1.342(4)C(11)—C(12)1.507(3)C(12)—H(12A)0.9600C(12)—H(12B)0.9600C(12)—H(12C)0.9600C(13)—C(16)1.459(3)C(13)—C(14)1.518(3)C(14)—C(15)1.456(5)C(15)—H(15A)0.9600C(15)—H(15B)0.9600C(15)—H(15C)0.9600C(17)—C(21)1.533(4)C(17)—C(18)1.540(4)C(17)—H(17)0.9800C(18)—C(19)1.519(5)C(18)—H(18A)0.9700C(18)—H(18B)0.9700C(19)—C(20)1.449(6)C(19)—H(19A)0.9700C(19)—H(19B)0.9700C(20)—C(21)1.514(5)C(20)—H(20A)0.9700C(20)—H(20B)0.9700C(21)—H(21A)0.9700C(21)—H(21B)0.9700C(6)—N(1)—C(5)126.3(2)C(6)—N(1)—H(1X)114(2)C(5)—N(1)—H(1X)118(2)C(10)—N(2)—C(6)117.2(2)C(16)—N(3)—C(8)121.58(18)C(16)—N(3)—C(17)116.28(19)C(8)—N(3)—C(17)122.12(18)C(1)—O(1)—H(1Y)103(2)C(3)—O(2)—C(2)111.1(3)O(1)—C(1)—C(5)108.4(2)O(1)—C(1)—C(2)109.2(3)C(5)—C(1)—C(2)109.9(3)O(1)—C(1)—H(1A)109.8C(5)—C(1)—H(1A)109.8C(2)—C(1)—H(1A)109.8O(2)—C(2)—C(1)112.8(3)O(2)—C(2)—H(2A)109.0C(1)—C(2)—H(2A)109.0O(2)—C(2)—H(2B)109.0C(1)—C(2)—H(2B)109.0H(2A)—C(2)—H(2B)107.8O(2)—C(3)—C(4)112.4(4)O(2)—C(3)—H(3A)109.1C(4)—C(3)—H(3A)109.1O(2)—C(3)—H(3B)109.1C(4)—C(3)—H(3B)109.1H(3A)—C(3)—H(3B)107.9C(3)—C(4)—C(5)110.7(3)C(3)—C(4)—H(4A)109.5C(5)—C(4)—H(4A)109.5C(3)—C(4)—H(4B)109.5C(5)—C(4)—H(4B)109.5H(4A)—C(4)—H(4B)108.1N(1)—C(5)—C(1)111.9(2)N(1)—C(5)—C(4)110.5(3)C(1)—C(5)—C(4)109.7(2)N(1)—C(5)—H(5)108.2C(1)—C(5)—H(5)108.2C(4)—C(5)—H(5)108.2N(1)—C(6)—N(2)114.4(2)N(1)—C(6)—C(7)123.5(2)N(2)—C(6)—C(7)122.2(2)C(8)—C(7)—C(6)119.9(2)C(8)—C(7)—H(7)120.1C(6)—C(7)—H(7)120.1C(7)—C(8)—N(3)122.15(19)C(7)—C(8)—C(9)118.55(19)N(3)—C(8)—C(9)119.30(19)C(10)—C(9)—C(8)116.5(2)C(10)—C(9)—C(11)123.4(2)C(8)—C(9)—C(11)120.1(2)N(2)—C(10)—C(9)125.6(2)N(2)—C(10)—H(10)117.2C(9)—C(10)—H(10)117.2C(13)—C(11)—C(9)118.7(2)C(13)—C(11)—C(12)121.7(2)C(9)—C(11)—C(12)119.6(2)C(11)—C(12)—H(12A)109.5C(11)—C(12)—H(12B)109.5H(12A)—C(12)—H(12B)109.5C(11)—C(12)—H(12C)109.5H(12A)—C(12)—H(12C)109.5H(12B)—C(12)—H(12C)109.5C(11)—C(13)—C(16)122.7(2)C(11)—C(13)—C(14)122.6(2)C(16)—C(13)—C(14)114.8(2)O(3)—C(14)—C(15)121.1(3)O(3)—C(14)—C(13)119.8(3)C(15)—C(14)—C(13)119.0(3)C(14)—C(15)—H(15A)109.5C(14)—C(15)—H(15B)109.5H(15A)—C(15)—H(15B)109.5C(14)—C(15)—H(15C)109.5H(15A)—C(15)—H(15C)109.5H(15B)—C(15)—H(15C)109.5O(4)—C(16)—N(3)121.1(2)O(4)—C(16)—C(13)121.6(2)N(3)—C(16)—C(13)117.3(2)N(3)—C(17)—C(21)116.1(2)N(3)—C(17)—C(18)115.5(2)C(21)—C(17)—C(18)106.2(2)N(3)—C(17)—H(17)106.1C(21)—C(17)—H(17)106.1C(18)—C(17)—H(17)106.1C(19)—C(18)—C(17)104.7(3)C(19)—C(18)—H(18A)110.8C(17)—C(18)—H(18A)110.8C(19)—C(18)—H(18B)110.8C(17)—C(18)—H(18B)110.8H(18A)—C(18)—H(18B)108.9C(20)—C(19)—C(18)108.7(3)C(20)—C(19)—H(19A)110.0C(18)—C(19)—H(19A)110.0C(20)—C(19)—H(19B)110.0C(18)—C(19)—H(19B)110.0H(19A)—C(19)—H(19B)108.3C(19)—C(20)—C(21)106.6(3)C(19)—C(20)—H(20A)110.4C(21)—C(20)—H(20A)110.4C(19)—C(20)—H(20B)110.4C(21)—C(20)—H(20B)110.4H(20A)—C(20)—H(20B)108.6C(20)—C(21)—C(17)102.9(2)C(20)—C(21)—H(21A)111.2C(17)—C(21)—H(21A)111.2C(20)—C(21)—H(21B)111.2C(17)—C(21)—H(21B)111.2H(21A)—C(21)—H(21B)109.1

Symmetry transformations used to generate equivalent atoms.

Thus, one embodiment of the invention provides 3-acetyl-1-cyclopentyl-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one as a crystalline solid. In another further embodiment, the crystalline solid is anhydrous.

Acquisition of Powder X-ray Diffraction (PXRD) Data for Crystal 5

A sample the crystal 5 (anhydrous) was submitted for PXRD analysis and found to be a crystalline material (designated as Form I). Powder X-ray diffraction analysis was conducted using a Bruker D8 Advance diffractometer equipped with a Cu radiation source. The divergence slit was set at 10 mm continuous illumination. Diffracted radiation was detected by a LYNXEYE_EX detector with motorized slits. The X-ray tube voltage and amperage were set to 40 kV and 40 mA respectively. Data was collected at the Cu wavelength (CuKα=1.5418λ) in the Theta-Theta goniometer from 3.0 to 40.0 degrees 2-Theta using a step size of 0.01 degrees and a step time of 1.0 second with an antiscatter screen in place. Samples were rotated during data collection. Samples were prepared by placing them in a silicon low background sample holder and rotated during collection. Data were collected using Bruker DIFFRAC Plus software and analysis was performed by EVA diffract plus software. The PXRD data file was not processed prior to peak searching. Using the peak search algorithm in the EVA software, peaks selected with a threshold value of 1 were used to make preliminary peak assignments. To ensure validity, adjustments were manually made; the output of automated assignments was visually checked, and peak positions were adjusted to the peak maximum. Peaks with relative intensity of ≥3% were generally chosen. Typically, the peaks which were not resolved or were consistent with noise were not selected. A typical error associated with the peak position from PXRD stated in USP up to +1-0.2° 2-Theta (USP-941). One diffraction pattern was consistently observed and is provided inFIG. 1. A list of diffraction peaks expressed in terms of the degree 2θ and relative intensities with a relative intensity of 3.0% of a PXRD from a sample of crystal 5 (obtained by the methods provided herein) are shown in Table X1 below.

Examples 6 and 7

Step 4. Synthesis of (1S,2S)-2-[6-acetyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methyl-7-oxopyrido[2,3-d]pyrimidin-8(7H)-yl]-1-methylcyclopentyl acetate and (1R,2R)-2-[6-acetyl-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methyl-7-oxopyrido[2,3-d]pyrimidin-8(7H)-yl]-1-methylcyclopentyl acetate (C43)

Potassium carbonate (512 mg, 3.70 mmol) was added to a solution of C43 (170 mg, 0.371 mmol) in methanol (12 mL). The reaction mixture was stirred at room temperature for 24 hours, whereupon it was diluted with water and extracted with dichloromethane. The combined organic layers were dried over sodium sulfate, filtered, concentrated in vacuo, and purified via chromatography on silica gel (Gradient: 0% to 10% ethyl acetate in heptane) to provide a mixture of 6 and 7 as a pale yellow solid. Yield: 115 mg, 0.276 mmol, 74%. Separation of the two diastereomers was carried out using supercritical fluid chromatography (Column: Chiral Technologies Chiralcel OJ-H, 5 μm; Mobile phase: 4:1 carbon dioxide/methanol; Back pressure: 100 bar). The first-eluting diastereomer was designated as 6, and the second-eluting diastereomer as 7; both were isolated as solids.

Examples 8 and 9

Step 3. Synthesis of rac-(3S,4R)-4-amino-2,2-dimethyltetrahydro-2H-pyran-3-ol, Hydrochloride Salt (C46)

A solution of C45 (2.0 g, 8.5 mmol) in methanol (85 mL) was degassed with nitrogen and then treated with 20% palladium hydroxide on carbon (400 mg). This mixture was stirred under a balloon of hydrogen for 16 hours, whereupon 20% palladium hydroxide on carbon (400 mg) was again added and hydrogenation was continued for 3 days. After the catalyst had been removed via filtration, the filter cake was washed with methanol (30 mL), and the combined filtrates were treated with hydrochloric acid (4 M; 10.7 mL, 43 mmol). The resulting mixture was concentrated in vacuo (10 mm Hg, 40° C.), providing a light brown solid. This was mixed with diethyl ether (30 mL) and sonicated; the clear ether layer was decanted off, and the remaining gummy solid was dried to provide C46 as a light brown solid. Yield: 820 mg, 4.5 mmol, 53%. LCMS m/z 146.3 [M+H]+.1H NMR (400 MHz, DMSO-d6) δ 8.22 (br s, 3H), 3.58-3.44 (m, 2H), 3.23 (d, J=10.2 Hz, 1H), 3.15-3.02 (m, 1H), 1.98-1.89 (m, 1H), 1.73-1.59 (m, 1H), 1.14 (s, 3H), 1.06 (s, 3H).

A vial containing a solution of P6 (317 mg, 1.04 mmol), C46 (290 mg, 1.6 mmol), and N,N-diisopropylethylamine (0.90 mL, 5.2 mmol) in dimethyl sulfoxide (4 mL) was capped and heated to 80° C. (block temperature) with stirring for 16 hours. The reaction mixture was then partitioned between dichloromethane (100 mL) and saturated aqueous sodium bicarbonate solution (20 mL), and the aqueous layer was extracted with dichloromethane (30 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. Separation of the component enantiomers was carried out using supercritical fluid chromatography (Column: Chiral Technologies Chiralpak AD-H, 5 μm; Mobile phase: 3:2 carbon dioxide/methanol; Back pressure: 100 bar); the first-eluting enantiomer, which exhibited a negative (−) rotation, was designated as 8, and the second-eluting enantiomer, which exhibited a positive (+) rotation, was designated as 9. From examination of the1H NMR spectra, both of these materials were assumed to exist as a mixture of rotamers.

Examples 12 and 13

Step 1. Synthesis of 8-[(1S,2R,5R)-bicyclo[3.1.0]hexan-2-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one and 8-[(1R,2S,5S)-bicyclo[3.1.0]hexan-2-yl]-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one (C50)

A mixture of P9 (260 mg, 0.897 mmol), (3S,4R)-4-aminotetrahydro-2H-pyran-3-ol (158 mg, 1.35 mmol), and N,N-diisopropylethylamine (348 mg, 2.69 mmol) in dimethyl sulfoxide (3 mL) was stirred at 70° C. for three hours, whereupon the reaction mixture was poured into water (50 mL) and extracted with ethyl acetate (2×50 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. After the residue had been combined with the product from a similar reaction carried out using P9 (30 mg, 0.10 mmol), it was purified using silica gel chromatography (Gradient: 0% to 5% methanol in dichloromethane) to afford C50, which consisted of the indicated mixture of 2 diastereomers, as a white solid. Combined yield: 150 mg, 0.421 mmol, 42%.

Step 2. Synthesis of 8-[(1S,2R,5R)-bicyclo[3.1.0]hexan-2-yl]-6-bromo-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one and 8-[(1R,2S,5S)-bicyclo[3.1.0]hexan-2-yl]-6-bromo-2-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one (C51)

A solution of C50 (120 mg, 0.337 mmol), N-bromosuccinimide (65.9 mg, 0.370 mmol), and oxalic acid (3.0 mg, 33 μmol) in acetonitrile (10 mL) was stirred in a sealed tube for 5 hours at 25° C. Aqueous sodium bisulfite solution (10 mL) was added; after the resulting mixture had been stirred at room temperature for a few minutes, it was partitioned between ethyl acetate (50 mL) and water (50 mL), and the aqueous layer was extracted with ethyl acetate (2×50 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo, providing C51 (150 mg) as a gum. This material was progressed to the following step.

Examples 14 and 15

A 500 mL Erlenmeyer flask was charged with deionized water (27.0 mL), to which was added potassium phosphate buffer solution (pH 7.5, 1.0 M; 4.0 mL), aqueous magnesium chloride solution (0.165 M; 0.8 mL, 132 μmol) and a solution of 5 in acetonitrile (0.005 M; 0.16 mL, 0.8 μmol). The mixture was treated with female mouse liver microsomes (4.0 mL, Corning Gentest 452702), followed by the addition of a freshly prepared aqueous solution of NADPH (dihydronicotinamide adenine dinucleotide phosphate; 0.013 M; 4.0 mL, 52 μmol). The uncapped Erlenmeyer flask was shaken using a Thermo Scientific Precision shaker with a 1″ throw at 37° C. for 1 hour. The reaction mixture was divided into equal portions (20 mL each) and poured into two 50 mL Falcon conical centrifuge tubes. The solutions were quenched by adding acetonitrile (20 mL) to each Falcon tube. The Falcon tubes were vortexed and centrifuged at 3000 rpm for 5 minutes. The supernatant was decanted and transferred in equal portions (20 mL each) to two 50 mL Falcon conical centrifuge tubes and the solvent was evaporated using a EZ-2 Plus Genevac (1 hour HPLC setting, 34° C./238 mbar to 41° C./7 mbar). The remaining aqueous solutions were combined (˜20 mL) into a 50 mL Falcon conical centrifuge tube and treated with acetonitrile (0.5 mL) and neat formic acid (0.5 mL), then charged with deionized water to a final volume of 50 mL. The solution was divided into equal portions (25 mL each), poured into two high speed centrifuge tubes, and centrifuged at 40,000G for 30 minutes. The supernatant was decanted into a 50 mL glass conical tube and the solution was adsorbed onto a C18 HPLC column (Zorbax Polaris C18-A, 250×4.6 mm, 5 μm) using a JASCO PU-1580 HPLC pump at a flow rate of 0.8 mL/min over ˜60 minutes. The HPLC column was transferred to a Thermo LTQ Velos mass spectrometer in line with a Waters Acquity UHPLC instrument comprised of a quaternary pump, autosampler and photodiode array UV/vis detector. A gradient (0.1% formic acid in water (A) and acetonitrile (B)) was applied to separate products of interest. After passing through the photodiode array detector, the eluent was split at a ratio of approximately 15:1, with the larger portion going to a fraction collector, and the smaller portion to the mass spectrometer (fractions were collected every 20 seconds). Fractions containing peaks of interest were analyzed by UHPLC-UV-HRMS using an AB Sciex TripleTOF 5600-1 mass spectrometer in line with a Waters Acquity UPLC System-1. Samples were injected (2 μL) onto a C18 UHPLC column (Phenomenex Kinetex C18, 2.1×50 mm, 1.7 μm) and a 0.1% formic acid in water (A) and acetonitrile (B) gradient was applied at a flow rate of 0.4 mL/min, maintained at 40° C. After UHPLC-UV-HRMS analysis, fractions were pooled and the solvent was removed using an EZ-2 Plus Genevac (3 hour HPLC setting, 34° C./238 mbar to 41° C./7 mbar). The dried samples were analyzed by NMR spectroscopy and quantified by external calibration against the1H NMR spectrum of a 5.0 mM benzoic acid standard solution in DMSO-d6using the ERETIC2 function within Topspin V3.2. The first-eluting diastereomer collected was designated as 14 (DIAST-1). Yield: 18 μg, 45 nmol.1H NMR (600 MHz, DMSO-d6) δ 8.57 (s, 1H), 7.26 (d, J=7.5 Hz, 1H), 6.44 (s, 1H), 5.58-5.44 (m, 1H), 4.49-4.41 (m, 1H), 3.90-3.76 (m, 3H), 3.45-3.33 (m, 2H), 3.08 (t, J=10.3 Hz, 1H), 2.39 (s, 3H), 2.38-2.32 (m, 1H), 2.30-2.23 (m, 4H), 2.12-1.97 (m, 3H), 1.74 (t, J=10.8 Hz, 1H), 1.70-1.63 (m, 1H), 1.50-1.38 (m, 1H). HRMS (TOF, m/z): [M+H]+calcd for C21H28N3O5, 402.2029; found, 402.2031 (0.5 ppm). UHPLC retention time 2.605 minutes; Phenomenex Kinetex C18 column (2.1×50 mm, 1.7 μm); column temperature 40° C.; flow rate 0.1 mL/minute; detection range UV 220-400 nm; mobile phase: solvent A=formic acid (0.1%), solvent B=acetonitrile (100%); gradient elution: 0-0.5 minutes solvent A (95%) and solvent B (5%), 0.5-6.5 minutes solvent A (50%) and solvent B (50%), 6.5-7.9 minutes solvent A (20%) and solvent B (80%), 7.9-8.0 minutes solvent A (5%) and solvent B (95%), 8.0-9.1 minutes solvent A (95%) and solvent B (5%), 9.1-10.0 minutes solvent A (100%) and solvent B (0%); total run time 10.0 minutes.

In a similar manner, starting materials A2, A3, and A4 may be respectively converted to the diastereomers 3-acetyl-1-[(1R,3R)-3-hydroxycyclopentyl]-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one (D2), 3-acetyl-1-[(1S,3S)-3-hydroxycyclopentyl]-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one (D3), and 3-acetyl-1-[(1S,3R)-3-hydroxycyclopentyl]-7-{[(3S,4R)-3-hydroxytetrahydro-2H-pyran-4-yl]amino}-4-methyl-1,6-naphthyridin-2(1H)-one (D4).

Examples 16 and 17

Hydrogen chloride (4.0 M solution in 1,4-dioxane; 0.181 mL, 0.724 mmol) was added to a solution of C52 (91 mg, 0.24 mmol) in dichloromethane (2 mL), and the reaction mixture was stirred at room temperature for 1 hour. LCMS analysis of the reaction mixture at this point indicated the presence of the product C53: LCMS m/z 350.2 [M+H]+. Concentration in vacuo provided C53 as a solid, which was taken directly to the following step.

A solution of potassium peroxymonosulfate (Oxone®; 326 mg, 0.530 mmol) in water (1 mL) was added to a solution of C53 (from the previous step; 88 mg, 0.24 mmol) in tetrahydrofuran (4 mL), and the reaction mixture was stirred at room temperature for 16 hours. LCMS analysis of the reaction mixture at this point indicated the presence of the product C54: LCMS m/z 345.9 [(M−HF)+H]+. Water was added, and the resulting mixture was extracted twice with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo to afford C54 as a pale yellow solid. Yield: 89.0 mg, 0.24 mmol, quantitative over 2 steps.

To a solution of C56 (1.00 g, 2.39 mmol) in a mixture of tetrahydrofuran (40 mL) and water (20 mL) was added potassium peroxymonosulfate (Oxone®; 2.64 g, 4.29 mmol). The reaction mixture was stirred at room temperature (17° C.) for 3 hours, whereupon it was diluted with water (40 mL) and extracted with ethyl acetate (2×40 mL). The combined organic layers were washed with saturated aqueous sodium chloride solution (50 mL), dried over sodium sulfate, filtered, and concentrated in vacuo to afford C57 as a yellow gum, which was used without additional purification. Yield: 1.08 g, quantitative. LCMS m/z 473.1 [M+Na+].

A suspension of (3S,4R)-4-aminotetrahydro-2H-pyran-3-ol (226 mg, 1.93 mmol), C57 (700 mg, 1.55 mmol), and sodium carbonate (341 mg, 3.22 mmol) in tetrahydrofuran (15 mL) was stirred at room temperature (20° C.) for approximately 20 hours. The reaction mixture was then partitioned between water (35 mL) and ethyl acetate (35 mL), and the organic layer was washed with saturated aqueous sodium chloride solution (20 mL), dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified using chromatography on silica gel (Gradient: 0% to 10% methanol in dichloromethane) to provide C58 as a yellow gum. Yield: 700 mg, 1.44 mmol, 93%. LCMS m/z 510.2 [M+Na+].

A mixture of 2-(2,4-difluorophenyl)-5-fluoropyridine (2.46 g, 11.8 mmol) and iridium(III) chloride (1.56 g, 5.23 mmol) in 2-ethoxyethanol (24 mL) and water (10 mL) was degassed under vacuum and the reaction vessel was then charged with nitrogen. This evacuation cycle was repeated twice, whereupon the reaction mixture was heated to 120° C. for 18 hours. It was then cooled to room temperature (28° C.) and solids were collected via filtration; the filter cake was washed with water (150 mL) to provide C59 as a yellow solid. Yield: 3.11 g, 2.41 mmol, 92%.

A mixture of C62 (6.1 mg, 13 μmol) and potassium peroxymonosulfate (Oxone®; 15 mg, 24 μmol) in a mixture of tetrahydrofuran and water (4:1, 0.75 mL) was stirred at room temperature for 66 hours. The reaction mixture was then partitioned between water (0.75 mL) and ethyl acetate (2 mL), and the organic layer was eluted through a solid-phase extraction cartridge loaded with sodium sulfate; this extraction process was repeated, and solvent was removed in vacuo to provide intermediate C63 [6-acetyl-2-(decylsulfonyl)-8-(3,3-dimethylcyclobutyl)-5-methylpyrido[2,3-d]pyrimidin-7(8H)-one]. This material was dissolved in methanol (1 mL), and half of it was concentrated under reduced pressure and then treated with a solution of (3S,4R)-4-aminotetrahydro-2H-pyran-3-ol (1.2 mg, 10 μmol) in tetrahydrofuran (0.25 mL). The reaction vial was shaken at 65° C. overnight, whereupon the reaction mixture was partitioned between ethyl acetate (1.2 mL) and water (0.60 mL) with vortexing. The organic layer was eluted through a solid-phase extraction cartridge loaded with sodium sulfate; the extraction process was repeated using ethyl acetate (0.60 mL), and solvent was removed from the combined organic layers in vacuo. Purification was carried out via reversed-phase HPLC (Column: Waters Sunfire C18, 5 μm; Mobile phase A: 0.05% trifluoroacetic acid in water; Mobile phase B: 0.05% trifluoroacetic acid in acetonitrile; Gradient: 5% to 60% B) to provide 19. Yield: 1.6 mg, 4.0 μmol, 62%. LCMS m/z 401.4 [M+H]+. Retention time: 0.922 minutes (Column: Phenomenex Kinetex C18, 2.1×30 mm, 2.6 μm; Mobile phase A: 0.05% trifluoroacetic acid in water; Mobile phase B: 0.05% trifluoroacetic acid in acetonitrile; Gradient: 5% to 95% B over 2.0 minutes, then hold at 95% B for 0.7 minutes; Flow rate: 1.0 mL/minute).

In Vitro Purified Enzyme Assays to Determine Potency for CDKs

The Chelation-Enhanced Fluorescence (CHEF) monitors the phosphorylation state in real time where the level of fluorescence is directly proportional to the amount of phosphorylated substrate. CHEF exploits a synthetic α-amino acid with a side chain bearing an 8-hydroxyquinoline derivative (sulfonamido-oxine, Sox) which, upon coordination to Mg(II), relays information on the phosphorylation state of a proximal serine, threonine or tyrosine residue in peptide-based kinase substrates. Phosphorylation of a specific peptide (Catalog # AQT0258) from AssayQuant Technologies results in an increase in fluorescence at the excitation and emission wavelengths of 360 nm Ex/485 nm Em.

Examples along with DMSO (negative) and Palbociclib (positive) controls were added to 384-well plates at 100-fold their final concentrations followed by the addition of 10 nM CDK4/Cyclin D1 (LJIC-2007F1) or 10 nM CDK6/Cyclin D3 (LJIC-2009H2) for a 20 minute pre-incubation in assay buffer containing 40 mM HEPES, 1 mM Dithiothreito (DTT, 10 mM MgCl2, 1% Glycerol, 0.1% BSA. Enzyme reactions were initiated by the addition of AssayQuant Technologies peptide and ATP substrates (10 μM CHEF peptide (Catalog # AQT0258), 2 mM ATP) and allowed to proceed for 2 hours followed by fluorescence read of the reaction. Kideterminations were made from a plot of the fractional velocity as a function of inhibitor concentration fit to the Morrison equation with the enzyme concentration as a variable.

The purpose CDK4/Cyclin D1 assay is to evaluate the inhibition (% inhibition, Kiappand Kivalues) in the presence of small molecule inhibitors by using a fluorescence based microfluidic mobility shift assay. CDK4/Cyclin D1 catalyzes the production of ADP from ATP that accompanies the phosphoryl transfer to the substrate peptide 5-FAM-Dyrktide. The mobility shift assay electrophoretically separates the fluorescently labeled peptides (substrate and phosphorylated product) following the kinase reaction. Both substrate and product are measured and the ratio of these values is used to generate % Conversion of substrate to product by the LabChip EZ Reader. Typical reaction solutions contained 2% DMSO (±inhibitor), 10 mM MgCl2, 1 mM DTT, 3.5 mM ATP, 0.005% Tween-20, 3 μM 5-FAM-Dyrktide, 3 nM activated CDK4/Cyclin D1 in 40 mM HEPES buffer at pH 7.5.

Inhibitor Kideterminations for activated CDK4/Cyclin D1 (2007 E1/2008+PO4) were initiated with the addition of ATP (50 μL final reaction volume), following a eighteen minute pre-incubation of enzyme and inhibitor at 22° C. in the reaction mix. The reaction was stopped after 195 minutes by the addition of 50 μL of 30 mM EDTA. Kideterminations were made from a plot of the fractional velocity as a function of inhibitor concentration fit to the Morrison equation with the enzyme concentration as a variable.

The purpose of the CDK6/Cyclin D3 assay is to evaluate the inhibition (% inhibition, Kiappand Kivalues) in the presence of small molecule inhibitors by using a fluorescence based microfluidic mobility shift assay. CDK6/Cyclin D3 catalyzes the production of ADP from ATP that accompanies the phosphoryl transfer to the substrate peptide 5-FAM-Dyrktide The mobility shift assay electrophoretically separates the fluorescently labeled peptides (substrate and phosphorylated product) following the kinase reaction. Both substrate and product are measured and the ratio of these values is used to generate % conversion of substrate to product by the LabChip EZ Reader. Typical reaction solutions contained 2% DMSO (±inhibitor), 2% glycerol, 10 mM MgCl2, 1 mM DTT, 3.5 mM ATP, 0.005% Tween 20 (TW-20), 3 μM 5-FAM-Dyrktide, 4 nM activated CDK6/Cyclin D3 in 40 mM HEPES buffer at pH 7.5.

Inhibitor Kideterminations for activated CDK6/Cyclin D3 (LJIC-2009G1/2010+PO4) were initiated with the addition of ATP (50 μL final reaction volume), following a eighteen minute pre-incubation of enzyme and inhibitor at 22° C. in the reaction mix. The reaction was stopped after 95 minutes by the addition of 50 μL of 30 mM EDTA. Kideterminations were made from a plot of the fractional velocity as a function of inhibitor concentration fit to the Morrison equation with the enzyme concentration as a variable.

The purpose of the CDK6/Cyclin D1 assay is to evaluate the inhibition (% inhibition, Kiappand Kivalues) in the presence of small molecule inhibitors by using a fluorescence based microfluidic mobility shift assay. CDK6/Cyclin D1 catalyzes the production of ADP from ATP that accompanies the phosphoryl transfer to the substrate peptide 5-FAM-Dyrktide The mobility shift assay electrophoretically separates the fluorescently labeled peptides (substrate and phosphorylated product) following the kinase reaction. Both substrate and product are measured and the ratio of these values is used to generate % conversion of substrate to product by the LabChip EZ Reader. Typical reaction solutions contained 2% DMSO (±inhibitor), 2% glycerol, 10 mM MgCl2, 1 mM DTT, 3.5 mM ATP, 0.005% Tween 20 (TW-20), 3 μM 5-FAM-Dyrktide, 4 nM activated CDK6/Cyclin D1 in 40 mM HEPES buffer at pH 7.5.

Inhibitor Kideterminations for activated CDK6/Cyclin D1 (LJIC-2003 A2/1865) were initiated with the addition of ATP (50 μL final reaction volume), following a fifteen minute pre-incubation of enzyme and inhibitor at 22° C. in the reaction mix. The reaction was stopped after 35 minutes by the addition of 50 μL of 30 mM EDTA. Kideterminations were made from a plot of the fractional velocity as a function of inhibitor concentration fit to the Morrison equation with the enzyme concentration as a variable.

For all the CDK4 and CDK6 assays the Kiconstant for compounds were calculated for each enzyme using the Morrison equation. Fractional activity was measured at different compound concentrations, [I] and the data fit to the Morrison equation where [E] is the enzyme concentration, [S] is the ATP concentration, and KnAppis the apparent Km for ATP for each enzyme under each assay format. With the Kicalculations dependent on the assay conditions for each assay format the resulting Kibecomes assay independent with a strong one to one correlation of Kivalues for compounds tested in both assay formats.

For Ki Calculations, see also Morrison, J. F. (1969) Kinetics of the reversible inhibition of enzyme-catalysed reactions by tight-binding inhibitors,Biochimica et biophysica acta185, 269-286; and Murphy, D. J. (2004) Determination of accurate KI values for tight-binding enzyme inhibitors: an in silico study of experimental error and assay design,Analytical biochemistry327, 61-67.

In Table 2, assay data are presented to two (2) significant figures as the geometric mean (Ki) based on the number of replicates listed (Number). A cell having NA means there was no data for that Example in the indicated assay.

Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application for all purposes.