WO2020003093A1 - Pyridin-3-yl acetic acid derivatives as inhibitors of human immunodeficiency virus replication - Google Patents

Pyridin-3-yl acetic acid derivatives as inhibitors of human immunodeficiency virus replication Download PDF

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Publication number
WO2020003093A1
WO2020003093A1 PCT/IB2019/055298 IB2019055298W WO2020003093A1 WO 2020003093 A1 WO2020003093 A1 WO 2020003093A1 IB 2019055298 W IB2019055298 W IB 2019055298W WO 2020003093 A1 WO2020003093 A1 WO 2020003093A1
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Prior art keywords
mmol
butoxy
methyl
tert
bipyridin
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PCT/IB2019/055298
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French (fr)
Inventor
Makonen Belema
Kyle J. Eastman
John F. Kadow
Eric P. Gillis
B. Narasimhulu Naidu
Kyle E. Parcella
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VIIV Healthcare UK (No.5) Limited
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Publication of WO2020003093A1 publication Critical patent/WO2020003093A1/en

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
    • C07D401/14—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing three or more hetero rings
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
    • A61P31/12—Antivirals
    • A61P31/14—Antivirals for RNA viruses
    • A61P31/18—Antivirals for RNA viruses for HIV
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D405/00—Heterocyclic compounds containing both one or more hetero rings having oxygen atoms as the only ring hetero atoms, and one or more rings having nitrogen as the only ring hetero atom
    • C07D405/14—Heterocyclic compounds containing both one or more hetero rings having oxygen atoms as the only ring hetero atoms, and one or more rings having nitrogen as the only ring hetero atom containing three or more hetero rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D491/00—Heterocyclic compounds containing in the condensed ring system both one or more rings having oxygen atoms as the only ring hetero atoms and one or more rings having nitrogen atoms as the only ring hetero atoms, not provided for by groups C07D451/00 - C07D459/00, C07D463/00, C07D477/00 or C07D489/00
    • C07D491/02—Heterocyclic compounds containing in the condensed ring system both one or more rings having oxygen atoms as the only ring hetero atoms and one or more rings having nitrogen atoms as the only ring hetero atoms, not provided for by groups C07D451/00 - C07D459/00, C07D463/00, C07D477/00 or C07D489/00 in which the condensed system contains two hetero rings
    • C07D491/04—Ortho-condensed systems
    • C07D491/044—Ortho-condensed systems with only one oxygen atom as ring hetero atom in the oxygen-containing ring
    • C07D491/052—Ortho-condensed systems with only one oxygen atom as ring hetero atom in the oxygen-containing ring the oxygen-containing ring being six-membered
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D491/00—Heterocyclic compounds containing in the condensed ring system both one or more rings having oxygen atoms as the only ring hetero atoms and one or more rings having nitrogen atoms as the only ring hetero atoms, not provided for by groups C07D451/00 - C07D459/00, C07D463/00, C07D477/00 or C07D489/00
    • C07D491/02—Heterocyclic compounds containing in the condensed ring system both one or more rings having oxygen atoms as the only ring hetero atoms and one or more rings having nitrogen atoms as the only ring hetero atoms, not provided for by groups C07D451/00 - C07D459/00, C07D463/00, C07D477/00 or C07D489/00 in which the condensed system contains two hetero rings
    • C07D491/10—Spiro-condensed systems
    • C07D491/107—Spiro-condensed systems with only one oxygen atom as ring hetero atom in the oxygen-containing ring
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D491/00—Heterocyclic compounds containing in the condensed ring system both one or more rings having oxygen atoms as the only ring hetero atoms and one or more rings having nitrogen atoms as the only ring hetero atoms, not provided for by groups C07D451/00 - C07D459/00, C07D463/00, C07D477/00 or C07D489/00
    • C07D491/02—Heterocyclic compounds containing in the condensed ring system both one or more rings having oxygen atoms as the only ring hetero atoms and one or more rings having nitrogen atoms as the only ring hetero atoms, not provided for by groups C07D451/00 - C07D459/00, C07D463/00, C07D477/00 or C07D489/00 in which the condensed system contains two hetero rings
    • C07D491/10—Spiro-condensed systems
    • C07D491/113—Spiro-condensed systems with two or more oxygen atoms as ring hetero atoms in the oxygen-containing ring

Definitions

  • the invention relates to compounds, compositions, and methods for the treatment of human immunodeficiency virus (HIV) infection. More particularly, the invention provides novel inhibitors of HIV, pharmaceutical compositions containing such compounds, and methods for using these compounds in the treatment of HIV infection.
  • HIV human immunodeficiency virus
  • the invention also relates to methods for making the compounds hereinafter described.
  • agents are classified as either nucleotide reverse transcriptase inhibitors (NRTIs), non-nucleotide reverse transcriptase inhibitors (NNRTIs), protease inhibitors (Pis), integrase inhibitors (INIs), or entry inhibitors (one, maraviroc, targets the host CCR5 protein, while the other, enfuvirtide, is a peptide that targets the gp4l region of the viral gpl60 protein).
  • NRTIs nucleotide reverse transcriptase inhibitors
  • NRTIs non-nucleotide reverse transcriptase inhibitors
  • Pro protease inhibitors
  • IPIs integrase inhibitors
  • entry inhibitors one, maraviroc, targets the host CCR5 protein, while the other, enfuvirtide, is a peptide that targets the gp4l region of the viral gpl60 protein.
  • a pharmacokinetic enhancer with no antiviral activity
  • Allosteric Integrase Inhibitors useful for treating HIV are disclosed, for example, in PCT/1B2018/050022 and PCT/1B2018/050021.
  • the present invention discloses compounds of Formula I, or a pharmaceutically acceptable salt thereof,
  • R 3 is Ci-salkyl
  • R 4 is Ci- 4 alkyl
  • R 1 is pyridinyl or phenyl and is optionally substituted with 1 or 2 halogens;
  • Q is Ci- 6 alkyl optionally substituted with 1 to 3 halogens
  • R 5 is H, phenyl, phenyl-O-, C3- 6 cycloalkyl, C3- 6 cycloalkyl-0-, Ci- 6 alkyl-0-, pyrazolyl, tetrahydropyranyl, or tetrahydrafuranyl, and is optionally substituted with 1-3 substituents independently selected from halogen and Ci- 6 alkyl;
  • R 2 is
  • R 6 is Ci-6alkyl
  • R 7 is C2-6alkyl, phenyl, -0Ci-6alkyl, CN, or halogen
  • R 2 is optionally substituted with 1-3 substituents independently selected from halogen and Ci- 6alkyl.
  • the invention also provides a compound of Formula (I) or a pharmaceutically acceptable salt thereof for use in therapy.
  • the invention also provides a compound of Formula (I) or a pharmaceutically acceptable salt thereof for use in the treatment of HIV infection
  • the invention also provides the use of a compound of Formula (I) or a
  • the invention also provides a pharmaceutical composition comprising a compound or salt of the invention.
  • the invention provides a method of treating HIV infection comprising administering a compound or salt of the invention to a patient.
  • the invention provides a method for inhibiting HIV integrase.
  • R 3 is C3- 5 alkyl.
  • R 4 is methyl or ethyl.
  • R 1 is pyridinyl and is optionally substituted with a fluorine.
  • Q is Ci-6alkyl optionally substituted with 1-3 fluorines.
  • R 5 is optionally substituted with 1-3 substituents independently selected from F, Cl, and methyl.
  • R 2 is
  • R 6 is methyl
  • R 7 is C2-3alkyl, phenyl, OCH3, CN, or F; and is optionally substituted with 1-2 substituents independently selected from F and CFb.
  • the invention includes all pharmaceutically acceptable salt forms of the
  • salts are those in which the counter ions do not contribute significantly to the physiological activity or toxicity of the compounds and as such function as pharmacological equivalents. These salts can be made according to common organic techniques employing commercially available reagents. Some anionic salt forms include acetate, acistrate, besylate, bromide, chloride, citrate, fumarate,
  • glucouronate hydrobromide, hydrochloride, hydroiodide, iodide, lactate, maleate, mesylate, nitrate, pamoate, phosphate, succinate, sulfate, tartrate, tosylate, and xinofoate.
  • Some cationic salt forms include ammonium, aluminum, benzathine, bismuth, calcium, choline, diethylamine, diethanolamine, lithium, magnesium, meglumine,
  • the invention includes all stereoisomeric forms of the compounds including enantiomers and
  • the invention includes all tautomeric forms of the compounds.
  • the invention includes atropisomers and rotational isomers.
  • a method for treating or preventing an HIV infection in a patient having or at risk of having the infection comprising administering to the patient a therapeutically effective amount of a compound disclosed herein, or a pharmaceutically acceptable salt thereof, in combination with a therapeutically effective amount of one or more additional therapeutic agents.
  • compositions comprising a compound disclosed herein, or a pharmaceutically acceptable salt thereof, in combination with one or more additional therapeutic agents, and a pharmaceutically acceptable carrier, diluent or excipient are provided.
  • compositions comprising a compound disclosed herein, or a pharmaceutically acceptable salt thereof, in combination with one or more additional therapeutic agents, and a pharmaceutically acceptable carrier, diluent or excipient are provided.
  • Preferred compositions include tablets and parenteral formulations.
  • combination pharmaceutical agents comprising a compound disclosed herein, or a pharmaceutically acceptable salt thereof, in combination with one or more additional therapeutic agents are provided.
  • the additional therapeutic agent may be an anti-HIV agent.
  • the additional therapeutic agent is selected from the group consisting of HIV protease inhibitors, HIV non-nucleoside inhibitors of reverse transcriptase, HIV nucleoside inhibitors of reverse transcriptase, HIV nucleotide inhibitors of reverse transcriptase, HIV integrase inhibitors, HIV non-catalytic site (or allosteric) integrase inhibitors, entry inhibitors (e.g., CCR5 inhibitors, gp4l inhibitors (i.e., fusion inhibitors) and CD4 attachment inhibitors), CXCR4 inhibitors, gpl20 inhibitors, G6PD and NADH-oxidase inhibitors, compounds that target the HIV capsid ("capsid inhibitors"; e.g., capsid polymerization inhibitors or capsid disrupting compounds such as those disclosed in WO 2013/006738 (Gilead Sciences), US 2013/016
  • “Combination,”“coadministration,”“concurrent” and similar terms referring to the administration of a compound of Formula I with at least one anti-HIV agent mean that the components are part of a combination antiretroviral therapy or highly active antiretroviral therapy (“HAART”) as understood by practitioners in the field of AIDS and HIV infection.
  • HAART highly active antiretroviral therapy
  • Patient means a person infected with the HIV virus.
  • Treatment “therapy,”“regimen,”“HIV infection,”“ARC,”“AIDS” and related terms are used as understood by practitioners in the field of AIDS and HIV infection.
  • Liquid compositions are usually in dosage unit ranges. Generally, the liquid
  • composition will be in a unit dosage range of about 1-100 milligram per milliliter
  • mg/mL Some examples of dosages are 1 mg/mL, 10 mg/mL, 25 mg/mL, 50 mg/mL, and 100 mg/mL.
  • other antiretroviral agents will be present in a unit range similar to agents of that class used clinically. Typically, this is about 1-100 mg/mL.
  • the invention encompasses all conventional modes of administration; oral and parenteral methods are preferred. Methods of Synthesis
  • the compounds of this invention can be made by various methods known in the art including those of the following schemes and in the specific embodiments section.
  • the structure numbering and variable numbering shown in the synthetic schemes are distinct from, and should not be confused with, the structure or variable numbering in the claims or the rest of the specification.
  • the variables in the schemes are meant only to illustrate how to make some of the compounds of this invention.
  • the disclosure is not limited to the foregoing illustrative examples and the examples should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, rather than to the foregoing examples, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.
  • Some compounds can be synthesized from an appropriately substituted heterocycle 1-1 according to Scheme I.
  • Compounds 1-1 and 1-6 are commercially available or synthesized by reactions well known in the art.
  • Treatment of compound 1-1 with bromine provided the dibromo intermediates 1-2 which was converted to the chloropyridine 1-3 by reacting with POCb.
  • Intermediate 1-3 conveniently transformed to ketoester 1-5 using conditions well-known to those skilled in the art, including reacting 1-3 with Grignard reagent in the presence of catalytic copper(I) bromide dimethylsulfide complex followed by alkyl 2-chloro-2-oxoacetate.
  • the boronate or boronic acid coupling reagents are commercially available or are prepared by reactions well-known to those skilled in the art.
  • Intermediates 1-10 are conveniently transformed to intermediates II-2 using conditions well-known in the art, including but not limited to the Suzuki coupling between intermediates 1-10 and II-l. Cleavage of protecting group in II-2 provided phenol II-3. Alkylation of the phenol II-3 was achieved by using conditions well known to those skilled in the art, including but not limited to Mitshunobu reaction to provide the intermediate II- 4. Hydrolysis of intermediate II-4 by using conditions well-known in the literature furnished carboxylic acid II-5.
  • some compounds of this invention can be synthesized according to Scheme III.
  • Pyridine III-l can be produced using methods similar to those described in the previous schemes.
  • This intermediate can be carried on to the final products by a variety of paths.
  • the C2 and C6 alkyl groups can be oxidized to furnish intermediates III-3 and/or III-4 which can be further transformed to final compounds III-9 or III-10 by methods well known in the art.
  • some compounds of this invention can be synthesized according to Scheme IV.
  • Pyridine III-5 can be transformed to the final products by several paths.
  • the C6 hydroxymethyl is oxidized to furnish carboxylic acid IV-1 which upon heating in the presence of acid provided C6-desmethyl analog IV-2.
  • The“Pd” mediated coupling of boronate IV-2 with appropriate aryl halides or aryl triflate followed by hydrolysis furnished the target compounds.
  • the target compounds could be synthesized by coupling intermediate IV-2 with aryl halides under Negishi coupling conditions followed by ester hydrolysis.
  • FhO/acetonitrile with 0.1% TFA and mobile phase B A: 9: 1 acetonitrile/FhO with 0.1% TFA; or mobile phase A: water/MeOH (9: 1) with 20 mM NFBOAc and mobile phase B: 95:5 MeOFl/FhO with 20 mM NFBOAc or mobile phase A: water/MeOH (9: 1) with 0.1% TFA and mobile phase B: 95:5 MeOFl/FhO with 0.1% TFA or mobile Phase A: 5:95 acetonitrile: water with l0-mM ammonium acetate; Mobile Phase B: 95:5 acetonitrile: water with l0-mM ammonium acetate.
  • LCMS Method 3 Column: Waters Acquity UPLC BEH C 18, 2.1 x 50 mm, 1.7- pm particles; Mobile Phase A: 5:95 acetonitrile:water with 10 mM ammonium acetate; Mobile Phase B: 95:5 acetonitrile:water with 10 mM ammonium acetate; Temperature: 50 °C; Gradient: 0-100% B over 3 minutes, then a 0.75-minute hold at 100% B; Flow: 1.0 mL/min; Detection: UV at 220 nm.
  • methyliminodiacetic acid (16.24 g, 110 mmol) and DMSO (97 ml).
  • the center neck was fitted with a pressure-equalizing addition funnel vented to positive N2 pressure.
  • Another neck was fitted with a rubber septum through which a thermocouple was inserted to monitor internal temperature.
  • the final neck was fitted with a short-path distillation apparatus collecting in a 100 mL r.b. flask and vented to a bubbler. This provides a slow stream of N2 carrier gas through the setup and out through the bubbler so that THF vapor does not accumulate.
  • the reaction solution containing the boronate was transfered to the addition funnel.
  • the 3-neck flask was heated with an oil bath (160 °C). Once the internal temperature had reached 115-120 °C the boronate solution was added dropwise at a rate necessary to maintain an internal temp of 115-120 °C. The addition took approximately 20 min.
  • the receiver flask containing the THF was exchanged for an empty 100 mL r.b. flask.
  • the bubbler line connected to the vacuum arm of the distillation apparatus was exchanged for a tube running to the rotovap.
  • the N2 source was closed.
  • the system was placed under vacuum, slowly ramping upon at which the DMSO distilled. The distillation was maintained until only trace DMSO remained.
  • the resulting powder was subjected to S1O2 purification (80g S1O2, hexanes:EtOAc 100:0 ⁇ 80:20) to afford a colorless oil that crystallized upon standing to afford 2-bromo-5-(4-fluorophenethoxy)pyridine (1.5337 g, 90 %) as a colorless, crystalline solid.
  • n- butyllithium in hexanes 8.33 ml, 20.8 mmol
  • the rate was approximately 0.25-0.50 mL/min.
  • the solution slowly began to turn a deep amber color.
  • the mixture was stirred for lh up which the solution was observed to be a deep amber color.
  • the bath was removed and the solution was allowed to warm to r.t. with stirring for 3h.
  • a distillation apparatus was assembled as follows: a 3-neck 250 mL flask equipped with a large stir bar was charged with methyliminodiacetic acid (6.06 g, 41.2 mmol) and DMSO (36.2 ml); the center neck was fitted with a pressure-equalizing addition funnel vented to positive N2 pressure; another neck was fitted with a rubber septum through which a thermocouple was inserted to monitor internal temperature; and the final neck was fitted with a short-path distillation apparatus collecting into a 250 mL r.b. flask and vented to a bubbler. The reaction solution containing the boronate was transfered to the addition funnel. The 3-neck flask was heated with an oil bath (160 °C).
  • the boronate solution was added dropwise at a rate necessary to maintain an internal temp of 115-120 °C. The addition took approximately 20 min.
  • the receiver flask containing the THF was exchanged for an empty 200 mL r.b. flask.
  • the bubbler line connected to the vacuum arm of the distillation apparatus was exchanged for a tube running vacuum.
  • the N2 source was closed.
  • the system was placed under vacuum, slowly ramping to 30 Torr upon which the DMSO distilled.
  • the distillation was maintained at 30 Torr until only trace DMSO remained.
  • the resulting residue, a solid, was dissolved in MeCN upon which only a white powder did not dissolve.
  • the mixture was concentrated onto Celite in vacuo.
  • the material was diluted with hexane:Et 2 0 (1 :1, 850 mL). A precipitate was immediately formed. The mixture was stirred for 5 minutes, then the liquid was decanted and reserved. The solids were treated with Et 2 0 (200 mL), and the mixture was stirred for 5 minutes. The solution was diluted with hexanes (200 mL), and the mixture was then stirred for 5 minutes. The mixture and the reserved solution were combined and filtered through a fine-fritted vacuum funnel. The filtrate was concentrated in vacuo. The resulting residue was diluted with a small amount of acetone and then concentrated onto Celite in vacuo. The resulting powder was subjected to Si0 2
  • the addition funnel was fitted onto the center neck of a 3-neck 250 mL flask equipped with a large stir bar was charged with N-methyliminodiacetic acid (24.35 g, 165 mmol) and DMSO (150 ml).
  • a side neck was fitted with a thermocouple.
  • the other side neck was fitted with a water-cooled short-path distillation apparatus collecting into a 250 mL round bottom flask and vented to a bubbler.
  • the addition funnel was capped with a gas adapter connected to a low-volume stream of N2 gas.
  • the 3 -neck flask was heated with an oil bath (150 °C).
  • the boronate solution was added dropwise at a rate necessary to maintain an internal temp of 115-120 °C.
  • the blue boronate solution immediately becomes a red/amber color upon contacting the DMSO solution.
  • the reaction mixture is a deep amber solution.
  • the receiver flask containing THF was exchanged for an empty 200 mL round bottom flask.
  • the bubbler line connected to the vacuum arm of the distillation apparatus was exchanged for a controlled vacuum source.
  • the N2 source feeding into the addition funnel was closed.
  • the system was placed under vacuum, slowly ramping to 30 Torr.
  • the receiver flask was emptied, then the vacuum was slowly ramped to 2 Torr.
  • the bath temperature was set to 125 °C and the pressure was maintained at 2 Torr.
  • the pressure was maintained at 2 Torr.
  • MeCN 100 mL
  • Heating was maintained until the solvent had reached reflux, then heating was stopped.
  • Celite Celite The mixture was concentrated in vacuo to afford a clumpy solid which was subjected to S1O2 chromatography
  • Step 1 To a solution of 2-(2-chlorophenoxy)ethan-l-ol (1.2 g, 6.95 mmol) and TEA (2.91 mL, 20.86 mmol) in THF (20 mL) was added dropwise Ms-Cl (0.813 mL,
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.103 mmol) in DMF (10 mL), 2-(2-chlorophenoxy)ethyl methanesulfonate (78 mg, 0.310 mmol) and was adde K2CO3 (71.4 mg, 0.517 mmol) and the mixture was stirred for 20 hours at 45 °C.
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetate (53 mg, 0.083 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.96 mg, 0.249 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC
  • Step 1 To a solution of 2-phenoxyethan-l-ol (1 g, 7.24 mmol) and TEA (3.03 mL, 21.71 mmol) in THF (20 mL) was added dropwise Ms-Cl (0.846 mL, 10.86 mmol)at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. LCMS showed that SM was consumed completely. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaHCCh, (10 ml) and brine (10 ml).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.103 mmol) in DMF (10 mL) was added K2CO3 (71.4 mg, 0.517 mmol) and 2-phenoxyethyl methanesulfonate (67.1 mg, 0.310 mmol). Then, the mixture was stirred at 45 °C for 20 hours and diluted with water and ethyl acetate (30 mL).
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.084 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.13 mg, 0.253 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate ( 5 ml) and concentrated to give crude product.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.103 mmol) in DMF (10 mL) was added K2CO3 (14.29 mg, 0.103 mmol) and l-bromobutane (14.17 mg, 0.103 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-butoxy-4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.096 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (1 1.56 mg, 0.289 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product.
  • Step 1 To a solution of 2-(l,3-dimethyl-lH-pyrazol-4-yl)ethan-l-ol (250 mg, 1.783 mmol) and triethylamine (271 mg, 2.68 mmol) in DCM (10 mL) was added methanesulfonyl chloride (225 mg, 1.962 mmol) at 0 °C . The mixture was stirred at rt for 1 h. The mixture was taken up into aqueous Na2C03 (20 mL) and extracted with DCM (10 ml X 3).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.103 mmol) in DMF (10 mL) was added K2CO3 (71.4 mg, 0.517 mmol) and 2-(l,3-dimethyl- lH-pyrazol-4-yl)ethyl methanesulfonate (67.7 mg, 0.310 mmol).
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetate (41 mg, 0.068 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.12 mg, 0.203 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l- yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (42.9 mg, 0.310 mmol) and (bromomethyl)cyclopropane (25.1 mg, 0.186 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)- 4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.056 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.69 mg, 0.167 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (31 mg, 0.064 mmol) in DMF (10 mL) was added K2CO3 (26.6 mg, 0.192 mmol) and
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-4'- (4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (31 mg, 0.056 mmol) in methanol (10 mL) and water (2 mL) was added NaOH (2.247 mg, 0.056 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) and K2CO3 (42.9 mg, 0.310 mmol) was added 2-(2- bromoethoxy)propane (31.1 mg, 0.186 mmol). The mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-(2-isopropoxyethoxy)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (26 mg, 0.046 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (5.48 mg, 0.137 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product.
  • Step 1 To a solution of 2-(tert-butoxy)ethan-l-ol (1 g, 8.46 mmol) and TEA (3.54 mL, 25.4 mmol) in THF (15 mL) was added dropwise Ms-Cl (0.989 mL, 12.69 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. TLC showed that SM was consumed completely. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaHCCh, (10 ml) and brine (10 ml).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added 2-(tert-butoxy)ethyl methanesulfonate (18.26 mg,
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(tert-butoxy)ethoxy)- 4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (40 mg, 0.069 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.22 mg, 0.206 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of 4,4,4-trifluorobutan-l-ol (2 g, 15.61 mmol) and TEA (2.176 mL, 15.61 mmol) in THF (20 mL) was added dropwise Ms-Cl (1.217 mL, 15.61 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaHCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S0 4 , filtered and concentrated to give 4,4,4-trifluorobutyl methanesulfonate (2.5g,
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added 4,4,4-trifluorobutyl methanesulfonate (12.79 mg, 0.062 mmol) and K2CO3 (8.57 mg, 0.062 mmol) and stirred for 20 hours at 45 °C.
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate (42 mg, 0.071 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.49 mg, 0.212 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC
  • Step 1 To a solution of (tetrahydro-2H-pyran-4-yl)methanol (1 g, 8.61 mmol) and TEA (2.400 mL, 17.22 mmol) in THF (15 mL) was added dropwise Ms-Cl (1.006 mL, 12.91 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaElCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S0 4 , filtered and concentrated to give (tetrahydro-2H-pyran-4-yl)methyl
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and (tetrahydro-2H- pyran-4-yl)methyl methanesulfonate (18.07 mg, 0.093 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL).
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]- 5'-yl)acetate (30 mg, 0.052 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.19 mg, 0.155 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of (tetrahydrofuran-3-yl)methanol (1 9, 9.79 mmol) and TEA (1.365 mL, 9.79 mmol) in THF (15 mL) was added dropwise Ms-Cl (0.763 mL, 9.79 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaElCCh, (10 ml) and brine (10 ml).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and (tetrahydrofuran-3- yl)methyl methanesulfonate (22.36 mg, 0.124 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL).
  • Step 3 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'-bipyridin]-5'- yl)acetate (35 mg, 0.062 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (7.40 mg, 0.185 mmol) and stirred for 20 hours at 100 °C.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (40 mg, 0.083 mmol) in DMF (10 mL) was added K2CO3 (34.3 mg, 0.248 mmol) and 2-(tetrahydro-2H- pyran-4-yl)ethyl methanesulfonate (25.8 mg, 0.124 mmol). The mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL).
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]- 5'-yl)acetate (51 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and l-bromobutan-2- one (18.73 mg, 0.124 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL).
  • Step 2 The mixture of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-(2-oxobutoxy)-[2, 3'-bipyridin]-5'-yl)acetate (15 mg, 0.027 mmol) and DAST (5 mL) was stirred for 20 hours at 20 °C and diluted with water and ethyl acetate (30 mL).
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-4'- (4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (8 mg, 0.014 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (1.667 mg, 0.042 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and extracted with ethyl acetate (5 ml). Organic layer concentrated and purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM
  • Step 1 To a solution of 2-(cyclopentyloxy)ethan-l-ol (1 g, 7.68 mmol) and TEA (2.141 mL, 15.36 mmol) in THF (l5 mL) was added dropwise Ms-Cl (0.898 mL, 11.52 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaElCCh, (10 ml) and brine (10 ml).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and 2- (cyclopentyloxy)ethyl methanesulfonate (15.50 mg, 0.074 mmol). The mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL).
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetate (30 mg, 0.050 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.04 mg, 0.151 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 ( 13.94 mg, 0.101 mmol) and 1 -bromobutane (13.82 mg, 0.101 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-butoxy-6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (46 mg, 0.083 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.00 mg, 0.250 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product.
  • the crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00 ⁇ to give the desired product (S)-2-(tert-butoxy)-2-(5-butoxy-6'- methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (13.1 mg, 0.026 mmol, 30.8 % yield) as white solid.
  • Prep-HPLC Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: Me
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-(2-chlorophenoxy)ethyl
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'- yl)acetate (54 mg, 0.083 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.96 mg, 0.249 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-phenoxyethyl methanesulfonate (65.4 mg, 0.303 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-5-(2- phenoxyethoxy)-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.084 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.13 mg, 0.253 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product.
  • the crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00 ⁇ to give the desired product (S)-2-(tert- butoxy)-2-(6'-methyl-5-(2-phenoxyethoxy)-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]- 5'-yl)acetic acid (11.9 mg, 0.021 mmol, 24.56 % yield).
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(l,3-dimethyl-lH-pyrazol-4-yl)ethyl methanesulfonate (22.02 mg, 0.101 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (42 mg, 0.068 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.16 mg, 0.204 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and bromocyclopropane (21.97 mg, 0.182 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)- 6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.055 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (2.183 mg, 0.055 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (32 mg, 0.065 mmol) in DMF (10 mL) , K2CO3 (8.92 mg, 0.065 mmol) and bromocyclobutane (8.72 mg, 0.065 mmol) was added. The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-6'- methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (32 mg, 0.057 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.81 mg, 0.170 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product.
  • the crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00 ⁇ to give the desired product (S)-2-(tert-butoxy)-2-(5- (cyclobutylmethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (7.7 mg, 0.015 mmol, 26.0 % yield) as white solid.
  • Prep-HPLC Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(2-bromoethoxy)propane (30.3 mg, 0.182 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-isopropoxyethoxy)- 6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (27 mg, 0.046 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (5.57 mg, 0.139 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added 2-(tert-butoxy)ethyl methanesulfonate (23.76 mg, 0.121 mmol) and K2CO3 (25.09 mg, 0.182 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(tert-butoxy)ethoxy)- 6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (41 mg, 0.069 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.26 mg, 0.206 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added 4,4,4-trifluorobutyl methanesulfonate (24.96 mg, 0.121 mmol) and K2CO3 (25.09 mg, 0.182 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate(42 mg, 0.069 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.32 mg, 0.208 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product.
  • the crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00 ⁇ to give the desired product (S)-2-(tert- butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'- bipyridin]-5'-yl)acetic acid (17.8 mg, 0.032 mmol, 45.5 % yield) as white solid.
  • Prep-HPLC Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (25.09 mg, 0.182 mmol) and (tetrahydro-2H-pyran-4-yl)methyl methanesulfonate (23.51 mg, 0.121 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]-5'- yl)acetate (32 mg, 0.054 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.47 mg, 0.162 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and (tetrahydrofuran-3- yl)methyl methanesulfonate (22.36 mg, 0.124 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetate (31 mg, 0.053 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.42 mg, 0.160 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (45 mg, 0.091 mmol) in DMF (10 mL) was added K2CO3 (37.6 mg, 0.272 mmol) and 2-(tetrahydro-2H-pyran-4-yl)ethyl methanesulfonate (28.4 mg, 0.136 mmol).
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]-5'- yl)acetate (52 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C.
  • Step 2 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'- yl)acetate (28 mg, 0.046 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (5.53 mg, 0.138 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (25.09 mg, 0.182 mmol) and l-bromobutan-2-one (18.28 mg, 0.121 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water.
  • Step 2 A mixture of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-5-(2-oxobutoxy)- 4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (16 mg, 0.028 mmol) and DAST (5 mL) was stirred for 20 hours at 20 °C.
  • Step 3 To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-6'- methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate ( 40mg, 0.068 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.17 mg, 0.204 mmol) and stirred for 20 hours at 100 °C.
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(cyclopentyloxy)ethyl methanesulfonate (42.0 mg, 0.202 mmol).
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetate (52 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 3 The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (34.6 mg, 0.061 mmol) were separated by SFC [Column AD-H 4.6 x 100 mm 5 pm; Co- Solvent EtOH(l% ammonia/methanol)] to obtain
  • Second eluting diastereomer 64 (7.2 mg, 0.012 mmol, 20.01 % yield).
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and (bromomethyl)cyclopropane (27.2 mg, 0.202 mmol).
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)- 6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.095 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (7.57 mg, 0.189 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 3 The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (32.1 mg, 0.063 mmol) were separated by SFC [Column AD-H 4.6 x 100 mm; 5 pm; Co-Solvent EtOH (l%ammonia/methanol)] to obtain
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(2-bromoethoxy)propane (33.7 mg, 0.202 mmol.
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and (tetrahydrofuran-3-yl)methyl methanesulfonate (36.4 mg, 0.202 mmol).
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'-bipyridin]-5'- yl)acetate (53 mg, 0.091 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.97 mg, 0.274 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) , was added 2-(tert-butoxy)ethyl methanesulfonate (39.6 mg, 0.202 mmol) and K2CO3 (41.8 mg, 0.303 mmol).
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(tert- butoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(tetrahydro-2H-pyran-4-yl)ethyl methanesulfonate (31.5 mg, 0.151 mmol).
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]- 5'-yl)acetate (52 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C.
  • Step 3 The diastereomers of (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]- 5'-yl)acetic acid (21.5 mg, 0.038 mmol) were separated by SFC [Column IC (4.6 x 100 mm; 5 pm); Co-Solvent MeOH (0.2%ammonia/methano)] to obtain
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-(2-chlorophenoxy)ethyl
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetate (50 mg, 0.077 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.23 mg, 0.231 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 3 The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (36.5 mg, 0.060 mmol) were separated by SFC [Column IC (4.6 x 100 mm; 5 um); Co-Solvent MeOH (0.2%ammonia/methanol)].
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and (tetrahydro-2H-pyran-4-yl)methyl methanesulfonate (29.4 mg, 0.151 mmol).
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]- 5'-yl)acetate (53 mg, 0.089 mmol) in methanol (10 mL) and water (2 mL) was added NaOH (10.71 mg, 0.268 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and l-bromobutane (27.6 mg, 0.202 mmol).
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-butoxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.094 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (3.77 mg, 0.094 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 3 The diastereomers of (2S)-2-(tert-butoxy)-2-(5-butoxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (28.8 mg, 0.057 mmol) were separated by SFC [Column AD-H (4.6 x 100 mm; 5 pm); Co-Solvent EtOH(l .0% ammonia/methanol)] to obtain
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.084 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.10 mg, 0.253 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 3 The diastereomers of (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (32.5 mg, 0.058 mmol) were separated by SFC (Column IC (4.6 x 100 mm; 5 pm); Co- Solvent MeOH (0.2%ammonia/methanol)] to obtain
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and (bromomethyl)cyclobutane (30.1 mg, 0.202 mmol).
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)- 6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.089 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.64 mg, 0.266 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 3 The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (29.5 mg,
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (80 mg, 0.161 mmol) in DMF (10 mL) was added K2CO3 (66.9 mg, 0.484 mmol) and l-bromobutan-2-one (48.7 mg, 0.323 mmol).
  • Step 2 A solution of 5'-((S)-l-(tert-butoxy)-2-isopropoxy-2-oxoethyl)-6'-methyl- 4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5-yl butyrate (72 mg, 0.127 mmol) in DAST (5 mL) was stirred for 20 hours at 20 °C.
  • Step 3 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)- 6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate ( 60mg, 0.102 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (12.25 mg, 0.306 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 4 The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (47.8 mg,
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-phenoxyethyl methanesulfonate (65.4 mg, 0.303 mmol) .
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.081 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.74 mg, 0.244 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml).
  • Step 3 The diastereomers of (2S)-2-(tert-Butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (28.5 mg, 0.050 mmol) were separated by SFC [Column AD-H 4.6 x 100 mm mm 5 um; Co-Solvent EtOH (l%ammonia/methanol)].
  • Step 1 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'-
  • Step 2 To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetate (50 mg, 0.081 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.71 mg, 0.243 mmol) and stirred for 20 hours at 100 °C.
  • Step 3 The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (29.2 mg, 0.051 mmol) were separated by SFC [Column AD-H 4.6 x 100 mm; 5 pm; C o- Sol vent EtOH (l%ammonia/methanol)] to obtain
  • a recombinant NL-RLuc proviral clone was constructed in which a section of the nef gene form NL4-3 was replaced with the Renilla Luciferase gene. This virus is fully infectious and can undergo multiple cycles of replication in cell culture.
  • the luciferous reporter provides a simple and easy method for quantitating the extent of virus growth and consequently, the antiviral activity of test compounds.
  • the plasmid pNLRLuc contains the proviral NL-Rluc DNA cloned into pUCl8 at the Pvull site.
  • the NL-RLuc virus was prepared by transfection of 293T cells with the plasmid pNLRLuc.
  • Transfections were performed using the LipofectAMINE PLUS kit form Invitrogen (Carlsbad, CA) according to the manufacturer and the virus generated was titered in MT-2 cells.
  • the titrated virus was used to infect MT-2 cells in the presence of compound, and after 5 days of incubation, cells were processed and quantitated for virus growth by the amount of expressed luciferase.
  • Assay media was RPMI 1640 supplemented with 10% heat inactivated fetal bovine serum (FBS), 100 units/ml penicillin G/100 units/ml streptomycin, 10 mM HEPES buffer pH 7.55 and 2 mM L-glutamine. The results form at least 2 experiments were used to calculate the EC50 values.

Abstract

Disclosed are compounds of Formula (I), including pharmaceutically acceptable salts, pharmaceutical compositions comprising the compounds, methods for making the compounds and their use in inhibiting HIV integrase and treating those infected with HIV or AIDS.

Description

PYRIDIN-3-YL ACETIC ACID DERIVATIVES AS INHIBITORS OF HUMAN IMMUNODEFICIENCY VIRUS REPLICATION
FIELD OF THE INVENTION
The invention relates to compounds, compositions, and methods for the treatment of human immunodeficiency virus (HIV) infection. More particularly, the invention provides novel inhibitors of HIV, pharmaceutical compositions containing such compounds, and methods for using these compounds in the treatment of HIV infection.
The invention also relates to methods for making the compounds hereinafter described.
BACKGROUND OF THE INVENTION
Current therapy for HIV-infected individuals consists of a combination of approved anti-retroviral agents. Over two dozen drugs are currently approved for HIV infection, either as single agents or as fixed dose combinations or single tablet regimens, the latter two containing 2-4 approved agents. These agents belong to a number of different classes, targeting either a viral enzyme or the function of a viral protein during the virus replication cycle. Thus, agents are classified as either nucleotide reverse transcriptase inhibitors (NRTIs), non-nucleotide reverse transcriptase inhibitors (NNRTIs), protease inhibitors (Pis), integrase inhibitors (INIs), or entry inhibitors (one, maraviroc, targets the host CCR5 protein, while the other, enfuvirtide, is a peptide that targets the gp4l region of the viral gpl60 protein). In addition, a pharmacokinetic enhancer with no antiviral activity, i.e., cobicistat, available from Gilead Sciences, Inc. under the tradename TYBOST™
(cobicistat) tablets, has recently been approved for use in combinations with certain antiretroviral agents (ARVs) that may benefit from boosting.
In the US, where combination therapy is widely available, the number of HIV-related deaths has dramatically declined (Palella, F. T; Delany, K. M.; Moorman, A. C.; Loveless, M. O.; Furher, T; Satten, G. A.; Aschman, D. T; Holmberg, S. D. N. Engl. J. Med. 1998, 338 , 853-860).
Unfortunately, not all patients are responsive and a large number fail this therapy. In fact, initial studies suggest that approximately 30-50% of patients ultimately fail at least one drug in the suppressive combination. Treatment failure in most cases is caused by the emergence of viral resistance. Viral resistance in turn is caused by the replication rate of HIV-l during the course of infection combined with the relatively high viral mutation rate associated with the viral polymerase and the lack of adherence of HIV-infected individuals in taking their prescribed medications. Clearly, there is a need for new antiviral agents, preferably with activity against viruses already resistant to currently approved drugs. Other important factors include improved safety and a more convenient dosing regimen than many of the currently approved drugs.
Compounds which inhibit HIV replication have been disclosed. See, for example, the following patent applications: W02007131350, W02009062285, W02009062288, W02009062289, W02009062308, W02010130034, W02010130842, WO2011015641, WO2011076765, WO2012033735, WO2013123148, WO2013134113, WO2014164467, WO2014159959, WO2015126726, and WO2017025915.
Allosteric Integrase Inhibitors useful for treating HIV are disclosed, for example, in PCT/1B2018/050022 and PCT/1B2018/050021.
What is now needed in the art are additional compounds which are novel and useful in the treatment of HIV. Additionally, these compounds may desireably provide advantages for pharmaceutical uses, for example, with regard to one or more of their mechanisms of action, binding, inhibition efficacy, target selectivity, solubility, safety profiles, or bioavailability.
BRIEF DESCRIPTION OF THE INVENTION
Briefly, in one aspect, the present invention discloses compounds of Formula I, or a pharmaceutically acceptable salt thereof,
Figure imgf000003_0001
wherein R3 is Ci-salkyl;
R4 is Ci-4alkyl;
R1 is pyridinyl or phenyl and is optionally substituted with 1 or 2 halogens;
Q is Ci-6alkyl optionally substituted with 1 to 3 halogens;
R5 is H, phenyl, phenyl-O-, C3-6cycloalkyl, C3-6cycloalkyl-0-, Ci-6alkyl-0-, pyrazolyl, tetrahydropyranyl, or tetrahydrafuranyl, and is optionally substituted with 1-3 substituents independently selected from halogen and Ci-6alkyl; R2 is
Figure imgf000004_0001
wherein R6 is Ci-6alkyl; R7 is C2-6alkyl, phenyl, -0Ci-6alkyl, CN, or halogen; and R2 is optionally substituted with 1-3 substituents independently selected from halogen and Ci- 6alkyl.
The invention also provides a compound of Formula (I) or a pharmaceutically acceptable salt thereof for use in therapy.
The invention also provides a compound of Formula (I) or a pharmaceutically acceptable salt thereof for use in the treatment of HIV infection
The invention also provides the use of a compound of Formula (I) or a
pharmaceutically acceptable salt thereof in the manufacture of a medicament for the treatment of HIV infection.
The invention also provides a pharmaceutical composition comprising a compound or salt of the invention.
In addition, the invention provides a method of treating HIV infection comprising administering a compound or salt of the invention to a patient.
In addition, the invention provides a method for inhibiting HIV integrase.
Also provided in accordance with the invention are methods for making the compounds and salts of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Preferably R3 is C3-5alkyl.
Preferably R4 is methyl or ethyl.
Preferably R1 is pyridinyl and is optionally substituted with a fluorine.
Pereferably Q is Ci-6alkyl optionally substituted with 1-3 fluorines.
Preferably R5 is optionally substituted with 1-3 substituents independently selected from F, Cl, and methyl.
Preferably R2 is
Figure imgf000005_0001
wherein R6 is methyl; R7 is C2-3alkyl, phenyl, OCH3, CN, or F; and is optionally substituted with 1-2 substituents independently selected from F and CFb.
The invention includes all pharmaceutically acceptable salt forms of the
compounds. Pharmaceutically acceptable salts are those in which the counter ions do not contribute significantly to the physiological activity or toxicity of the compounds and as such function as pharmacological equivalents. These salts can be made according to common organic techniques employing commercially available reagents. Some anionic salt forms include acetate, acistrate, besylate, bromide, chloride, citrate, fumarate,
glucouronate, hydrobromide, hydrochloride, hydroiodide, iodide, lactate, maleate, mesylate, nitrate, pamoate, phosphate, succinate, sulfate, tartrate, tosylate, and xinofoate. Some cationic salt forms include ammonium, aluminum, benzathine, bismuth, calcium, choline, diethylamine, diethanolamine, lithium, magnesium, meglumine,
4-phenylcyclohexylamine, piperazine, potassium, sodium, tromethamine, and zinc.
Some of the compounds of the invention exist in stereoisomeric forms. The invention includes all stereoisomeric forms of the compounds including enantiomers and
diastereromers. Methods of making and separating stereoisomers are known in the art. The invention includes all tautomeric forms of the compounds. The invention includes atropisomers and rotational isomers.
In one embodiment, a method for treating or preventing an HIV infection in a patient having or at risk of having the infection is provided, comprising administering to the patient a therapeutically effective amount of a compound disclosed herein, or a pharmaceutically acceptable salt thereof, in combination with a therapeutically effective amount of one or more additional therapeutic agents.
In one embodiment, pharmaceutical compositions comprising a compound disclosed herein, or a pharmaceutically acceptable salt thereof, in combination with one or more additional therapeutic agents, and a pharmaceutically acceptable carrier, diluent or excipient are provided.
In one embodiment, pharmaceutical compositions comprising a compound disclosed herein, or a pharmaceutically acceptable salt thereof, in combination with one or more additional therapeutic agents, and a pharmaceutically acceptable carrier, diluent or excipient are provided. Preferred compositions include tablets and parenteral formulations.
In one embodiment, combination pharmaceutical agents comprising a compound disclosed herein, or a pharmaceutically acceptable salt thereof, in combination with one or more additional therapeutic agents are provided.
In the above embodiments, the additional therapeutic agent may be an anti-HIV agent. For example, in some embodiments, the additional therapeutic agent is selected from the group consisting of HIV protease inhibitors, HIV non-nucleoside inhibitors of reverse transcriptase, HIV nucleoside inhibitors of reverse transcriptase, HIV nucleotide inhibitors of reverse transcriptase, HIV integrase inhibitors, HIV non-catalytic site (or allosteric) integrase inhibitors, entry inhibitors (e.g., CCR5 inhibitors, gp4l inhibitors (i.e., fusion inhibitors) and CD4 attachment inhibitors), CXCR4 inhibitors, gpl20 inhibitors, G6PD and NADH-oxidase inhibitors, compounds that target the HIV capsid ("capsid inhibitors"; e.g., capsid polymerization inhibitors or capsid disrupting compounds such as those disclosed in WO 2013/006738 (Gilead Sciences), US 2013/0165489 (University of Pennsylvania), and WO 2013/006792 (Pharma Resources), pharmacokinetic enhancers, and other drugs for treating HIV, and combinations thereof.
“Combination,”“coadministration,”“concurrent” and similar terms referring to the administration of a compound of Formula I with at least one anti-HIV agent mean that the components are part of a combination antiretroviral therapy or highly active antiretroviral therapy (“HAART”) as understood by practitioners in the field of AIDS and HIV infection.
“Patient” means a person infected with the HIV virus.
“Treatment,”“therapy,”“regimen,”“HIV infection,”“ARC,”“AIDS” and related terms are used as understood by practitioners in the field of AIDS and HIV infection.
Those terms not specifically set forth herein shall have the meaning which is commonly understood and accepted in the art.
Liquid compositions are usually in dosage unit ranges. Generally, the liquid
composition will be in a unit dosage range of about 1-100 milligram per milliliter
(“mg/mL”). Some examples of dosages are 1 mg/mL, 10 mg/mL, 25 mg/mL, 50 mg/mL, and 100 mg/mL. Generally, other antiretroviral agents will be present in a unit range similar to agents of that class used clinically. Typically, this is about 1-100 mg/mL.
The invention encompasses all conventional modes of administration; oral and parenteral methods are preferred. Methods of Synthesis
The compounds of this invention can be made by various methods known in the art including those of the following schemes and in the specific embodiments section. The structure numbering and variable numbering shown in the synthetic schemes are distinct from, and should not be confused with, the structure or variable numbering in the claims or the rest of the specification. The variables in the schemes are meant only to illustrate how to make some of the compounds of this invention. The disclosure is not limited to the foregoing illustrative examples and the examples should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, rather than to the foregoing examples, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.
Abbreviations used in the schemes and examples generally follow conventions used in the art. Chemical abbreviations used in the specification and examples are defined as follows:“KHMDS” for potasium bis(trimethylsilyl)amide; "DMF" for N,N- dimethylformamide;“HATU’ or 0-(t- Azabenzotriazol- 1 -yl)-N,N,N’ ,N’ - tetramethyluronium hexafluorophosphate,“MeOH” for methanol;“Ar” for aryl; "TFA" for trifluoroacetic acid,“DMSO” for dimethylsulfoxide;“h” for hours;“rt” for room temperature or retention time (context will dictate);“min” for minutes; "EtOAc" for ethyl acetate; "THF" for tetrahydrofuran;“Et20” for diethyl ether; "DMAP" for 4- dimethylaminopyridine;“DCE” for l,2-dichloroethane;“ACN” for acetonitrile;“DME” for l,2-dimethoxy ethane;“HOBt” for l-hydroxybenzotriazole hydrate; and“DIEA” for dii sopropy 1 ethyl amine .
Certain other abbreviations as used herein, are defined as follows:“1 x” for once,
“2 x” for twice,“3 x” for thrice, "°C" for degrees Celsius,“eq” for equivalent or equivalents,“g” for gram or grams,“mg” for milligram or milligrams,“L” for liter or liters,“mL” for milliliter or milliliters,“pL” for microliter or microliters,“N” for normal, “M” for molar,“mmol” for millimole or millimoles,“atm” for atmosphere,“psi” for pounds per square inch,“cone” for concentrate,“sat” or“sat’d“ for saturated,“MW” for molecular weight,“mp” for melting point,“ee” for enantiomeric excess,“MS” or“Mass Spec” for mass spectrometry,“ESI” for electrospray ionization mass spectroscopy,“HR” for high resolution,“HRMS” for high resolution mass spectrometry ,“LCMS” for liquid chromatography mass spectrometry,“HPLC” for high pressure liquid chromatography, “RP HPLC” for reverse phase HPLC,“TLC” or“tic” for thin layer chromatography, “NMR” for nuclear magnetic resonance spectroscopy,“iff” for proton,“d” for delta,“s” for singlet,“d” for doublet,“t” for triplet,“q” for quartet,“m” for multiplet,“br” for broad, “Hz” for hertz, and“a”,“b”,“R”,“S”,“E”, and“Z” are stereochemical designations familiar to one skilled in the art.
Some compounds can be synthesized from an appropriately substituted heterocycle 1-1 according to Scheme I. Compounds 1-1 and 1-6 are commercially available or synthesized by reactions well known in the art. Treatment of compound 1-1 with bromine provided the dibromo intermediates 1-2 which was converted to the chloropyridine 1-3 by reacting with POCb. Intermediate 1-3 conveniently transformed to ketoester 1-5 using conditions well-known to those skilled in the art, including reacting 1-3 with Grignard reagent in the presence of catalytic copper(I) bromide dimethylsulfide complex followed by alkyl 2-chloro-2-oxoacetate. Coupling of amines 1-5 with intermediate 1-6 in the presence of an organic base such as Hunig’s base provided intermediate 1 7 Chiral Lewis acid such as 1-8 mediated reduction of ketoester 1-7 with catecholborane furnished the chiral alcohol 1 9 Tertiary butylation of alcohol 1-9 by well-known conditions, including but not limited to tertiary-butyl acetate and perchloric acid, gave intermediate 1-10.
Intermediates 1-10 are conveniently transformed to intermediates 1-11 using conditions well-known in the art, including but not limited to the Suzuki coupling between
intermediates 1-10 and R6B(OR)2. The boronate or boronic acid coupling reagents, well- known in the art, are commercially available or are prepared by reactions well-known to those skilled in the art. Hydrolysis of intermediate 1-11 by using conditions well-known to those skilled in the art furnished the carboxylic acid 1-12.
Scheme I
Figure imgf000009_0001
Intermediates 1-10 are conveniently transformed to intermediates II-2 using conditions well-known in the art, including but not limited to the Suzuki coupling between intermediates 1-10 and II-l. Cleavage of protecting group in II-2 provided phenol II-3. Alkylation of the phenol II-3 was achieved by using conditions well known to those skilled in the art, including but not limited to Mitshunobu reaction to provide the intermediate II- 4. Hydrolysis of intermediate II-4 by using conditions well-known in the literature furnished carboxylic acid II-5.
Scheme II
Figure imgf000010_0001
In yet another method, some compounds of this invention can be synthesized according to Scheme III. Pyridine III-l, can be produced using methods similar to those described in the previous schemes. This intermediate can be carried on to the final products by a variety of paths. In one, the C2 and C6 alkyl groups can be oxidized to furnish intermediates III-3 and/or III-4 which can be further transformed to final compounds III-9 or III-10 by methods well known in the art.
Scheme III
Figure imgf000011_0001
In yet another process, some compounds of this invention can be synthesized according to Scheme IV. Pyridine III-5 can be transformed to the final products by several paths. In one path, the C6 hydroxymethyl is oxidized to furnish carboxylic acid IV-1 which upon heating in the presence of acid provided C6-desmethyl analog IV-2. The“Pd” mediated coupling of boronate IV-2 with appropriate aryl halides or aryl triflate followed by hydrolysis furnished the target compounds. Alternatively, the target compounds could be synthesized by coupling intermediate IV-2 with aryl halides under Negishi coupling conditions followed by ester hydrolysis.
Scheme IV
Figure imgf000012_0001
The compounds described herein were purified by the methods well known to those skilled in art by normal phase column chromatography on silica gel column using appropriate solvent system described. Preparative HPLC or preparative LC/MS
purifications mentioned in this experimentation section were carried out by gradient elution either on Sunfire Prep C18 ODB column (5 pm; 19 or 30 X 100 mm) or Waters Xbridge C18 column (5 pM; 19 X 200 or 30 X 100 mm) or Water Atlantis (5 pm; 19 or 30 X 100 mm) or Waters XBridge Cl 8, 2.1 mm x 50 mm, 1.7 pm particles using the following mobile phases. Mobile phase A: 9: 1 FhO/acetonitrile with 10 mM NH4OAc and mobile phase B: A: 9: 1 acetonitrile/FhO with 10 mM NFBOAc; or mobile phase A: 9: 1
FhO/acetonitrile with 0.1% TFA and mobile phase B: A: 9: 1 acetonitrile/FhO with 0.1% TFA; or mobile phase A: water/MeOH (9: 1) with 20 mM NFBOAc and mobile phase B: 95:5 MeOFl/FhO with 20 mM NFBOAc or mobile phase A: water/MeOH (9: 1) with 0.1% TFA and mobile phase B: 95:5 MeOFl/FhO with 0.1% TFA or mobile Phase A: 5:95 acetonitrile: water with l0-mM ammonium acetate; Mobile Phase B: 95:5 acetonitrile: water with l0-mM ammonium acetate.
Analysis Methods:
LCMS Method 1: Column: Waters XBridge Cl 8, 2.1 mm x 50 mm, 1.7 pm particles; Mobile Phase A: 5:95 acetonitrile:water with 10 mM ammonium acetate; Mobile Phase B: 95:5 acetonitrile: water with 10 mM ammonium acetate; Temperature: 50 °C; Gradient: 0 %B to 100 %B over 3 min, then a 0.75 min hold at 100 %B; Flow: 1 mL/min; Detection: MS and UV (220 nm).
LCMS Method 2: Column: Waters XBridge Cl 8, 2.1 mm x 50 mm, 1.7 mih particles; Mobile Phase A: 5:95 acetonitrile:water with 0.1 % trifluoroacetic acid; Mobile Phase B: 95:5 acetonitrile:water with 0.1 % trifluoroacetic acid; Temperature: 50 °C; Gradient: 0 %B to 100 %B over 3 min, then a 0.75 min hold at 100 %B; Flow: 1 mL/min; Detection: MS and UV (220 nm).
LCMS Method 3: Column: Waters Acquity UPLC BEH C 18, 2.1 x 50 mm, 1.7- pm particles; Mobile Phase A: 5:95 acetonitrile:water with 10 mM ammonium acetate; Mobile Phase B: 95:5 acetonitrile:water with 10 mM ammonium acetate; Temperature: 50 °C; Gradient: 0-100% B over 3 minutes, then a 0.75-minute hold at 100% B; Flow: 1.0 mL/min; Detection: UV at 220 nm.
LCMS Method 4: Column: Waters Acquity UPLC BEH C 18, 2.1 x 50 mm, 1.7- pm particles; Mobile Phase A: 5:95 acetonitrile:water with 0.05 % trifluoroacetic acid; Mobile Phase B: 95:5 acetonitrile:water with 0.05 % trifluoroacetic acid; Temperature: 40 °C; Gradient: 0 %B to 100 %B over 1.5 min, then a 0.5 min hold at 100 %B; Flow: 0.8 mL/min; Detection: MS and UV (220 nm).
LCMS Method 5: Column: Phenomenex Luna Cl 8, 2.0 x 30 mm, 3-pm particles; Mobile Phase A: 5:95 acetonitrile:water with 10 mM ammonium acetate; Mobile Phase B: 95:5 acetonitrile:water with 10 mM ammonium acetate; Temperature: 40 °C; Gradient: 0- 100% B over 2 minutes, then a l-minute hold at 100% B; Flow: 1.0 mL/min; Detection: UV at 220 nm.
Figure imgf000013_0001
To a stirred solution of 2-methylpyridin-4-ol (8.0 g, 73 mmol) in dichloromethane (90 ml) and MeOH (11 ml) was added tert-butylamine (15.7 ml, 148 mmol) and the mixture was cooled to 0 °C. Bromine (7.55 ml, 147 mmol) was added dropwise over a 20 minute period. The reaction mixture was stirred at rt for 2 hours. Then the resulting slurry was filtered through a buchner funnel and the solid was washed with methanol (100 ml) and dried overnight to afford 3,5-dibromo-2-methylpyridin-4-ol (10 g, 37.5 mmol, 51.1 % yield). LCMS Method 4: retention time = 0.704 min.; observed ion = 267.8. ¾ NMR (500 MHz, DMSO-de) d 12.33 (br s, 1H), 8.21 (s, 1H), 2.40 (s, 3H).
Figure imgf000014_0001
To a solution of 3,5-dibromo-2-methylpyridin-4-ol (13.5 g, 50.6 mmol) in POCb (13.7 ml, 147 mmol) was added triethylamine (7.05 ml, 50.6 mmol) at 0 °C slowly over 30 min. After addition, the ice bath was removed and was stirred at 80 °C for 1 h. The reaction mixture was cooled to rt and slowly quenched by adding it to crushed ice. The resulting slurry was diluted with DCM (250 mL) and slowly neutralized with 2M Na2CCb solution. Once neutralized the layers were separated and the organic layer was dried (Na2S04), filtered and concentrated to give 3,5-dibromo-4-chloro-2-methylpyridine (14 g, 49 mmol, 97 % yield) as a off white solid. LCMS Method 4: retention time = 1.47 min.; observed ion = 285.7. ¾ NMR (500 MHz, CHLOROFORM-d) d 8.56 (s, 1H), 2.72 (s, 3H).
Figure imgf000014_0002
To a 25 mL RB flask equipped with a stir bar and placed under N2 was added THF (9 ml) and 3,5-dibromo-4-chloro-2-methylpyridine (1.0 g, 3.5 mmol). The mixture was warmed to 60 °C. To the solution was added isopropylmagnesium chloride (2 M solution in THF) (1.8 ml, 3.7 mmol) dropwise at 60 °C. The solution was stirred for 1 minute. Then, to the solution was added bis(methylthio)copper(III) bromide (83 mg, 0.350 mmol) (copper bromide dimethylsulfide complex) as a solid at once. The solution was stirred at rt for 5 min. Then, to a dry 50 mL rb flask equipped with a stir bar and placed under N2 atm was added THF (9 ml) and isopropyl 2-chloro-2-oxoacetate (580 mg, 3.85 mmol). The flask was placed in a -78 °C bath and was stirred for 10 min. To the flask was added the organometallic suspension/solution prepared above via addition funnel. The mixture remained a suspension of fine black precipitate and a pale orange solution. The bath was allowed to warm to rt with stirring. LCMS analysis after l.5h found a peak with the expected product mass. Then, to the reaction mixture was added diethanolamine (403 mΐ, 4.21 mmol, (the diethanolamine is expected to coordinate both the Cu and the Mg) The mixture was transfered to a separatory funnel using water and Et20. The mixture was diluted with water and was extracted with Et20. The combined organics were washed with brine; dried over Na2S04 and filtered. The solution was concentraed in vacuo. The resulting residue was dissolved in a minimal of acetone and then concentrated onto celite in vacuo. The resulting powder was subjected to S1O2 purification. (Biotage, EtO Ac/hexanes gradient, 0-40% over 10 CVs). The first peak to elute is the desired minor isomer:
isopropyl 2-(5-bromo-4-chloro-2-methylpyridin-3-yl)-2-oxoacetate (186 mg, 0.580 mmol, 16.56 % yield). LCMS Method 4: retention time = 1.33 min.; observed ion = 320.0, 322.0. ¾ NMR (500 MHz, METHANOL-d4) d 8.63 (s, 1H), 4.33 (spt, =6.6 Hz, 1H), 2.82 (s,
3H), 1.72 - 1.68 (m, 6H).
General Procedure A
Figure imgf000015_0001
To a stirred solution of isopropyl 2-(5-bromo-4-chloro-2-methylpyridin-3-yl)-2- oxoacetate (500 mg, 1.56 mmol) and N-ethyl-N-isopropylpropan-2-amine (817 mΐ, 4.68 mmol, 3 equiv) in dry acetonitrile (0.2 M) was added the appropriate amine (1 equiv) and the resulting solution was placed in a heating block pre-heated to 80°C and stirred for 2 days. The reaction was then concentrated, adsorbed onto celite and was purified on silica gel (Biotage, EtOAc/hexanes gradient, 0-50% over 10 CVs) to give the expected product consistent by LCMS.
Figure imgf000015_0002
Figure imgf000016_0001
Figure imgf000017_0001
Figure imgf000018_0001
Figure imgf000019_0002
General Procedure B
Figure imgf000019_0001
To a stirred solution of the starting material (1.2 mmol) and (R)-l-methyl-3,3- diphenyltetrahydro-lH,3H-pyrrolo[l,2-c][l,3,2]oxazaborole (1M in toluene) (0.180 ml, 0.180 mmol, .15 equiv) in toluene (6 ml , 0.2M) was added dropwise catecholborane (50% in toluene, 0.360 ml, 1.680 mmol, 1.4 equiv) at -40 °C. Then the reaction (which were solutions) were placed in a -20°C freezer overnight. Each reaction was then, diluted with EtOAc and sat Na2CCh. The mixture was vigorously stirred for 1 hr. The aq. layer separated and organicc layer washed with sat Na2CCh 2x , dried (Na2S04), filtered, concentrated and purified on silica by flash chromatography (EtO Ac/Hex gradient 0-100% over 10 CVs) to afford the expected product consistent by LCMS.
Figure imgf000019_0003
Figure imgf000020_0001
Figure imgf000021_0001
Figure imgf000022_0001
Figure imgf000023_0002
General Procedure C
Figure imgf000023_0001
Perchloric acid (70%, 1.1 equiv) was added at once to a solution of the appropriate chiral alcohol starting material (1 equiv) in a r.b. flask with septum equipped with a balloon. Then 2-methylprop-l-ene (g) was bubbled into the mixture until the balloon began to inflate and then the gas was turned off. The reaction was allowed to stir overnight. The reaction mixture was diluted with more DCM and then washed with sat. Na2CCb (2x) to make the pH basic. Then the organic phase was washed with brine and dried over Na2S04, filtered and concentrated. The residue was adsorbed onto celite and was purified on silica gel (Biotage, EtO Ac/hexanes gradient, 0-100% over 10 CVs) to afford the desired product consistent by LCMS.
Figure imgf000024_0001
Figure imgf000025_0001
Figure imgf000026_0001
Figure imgf000027_0002
ND = yielc not determined. The product was carried directly into the next step
Figure imgf000027_0001
To a 500 mL r.b. flask equipped with a large stir bar was added 6-bromopyri din-3 - ol (10.0 g, 57.5 mmol), 2-methylpropan-l-ol (4.26 g, 57.5 mmol), triphenylphosphine (15.8 g, 60.3 mmol) and THF (192 ml). To the stirring solution was added DIAD (11.73 ml, 60.3 mmol) and after 15 min the reaction solution was concentrated in vacuo. To the crude reaction product was added hexanes:Et20 (1 : 1, 250 mL) and stirred. A signficant amount of crystalline material (Ph3PO) precipitated was removed via filtration. The filtrate was concentrated in vacuo and the residue was dissolved in a minimal of acetone and concentrated onto Celite. The resulting powder was subjected to Si02 purifciation on the Biotage (120 g column) 0-100% 10 CVs to afford 2-bromo-5-isobutoxypyridine (12.7 g, 96%) as a clear oil. LCMS Method 4: retention time = 1.36 min.; observed ion = 230.0, 232.0. ¾ NMR (500 MHz, CHLOROFORM-d) d 8.07 (d, =3.0 Hz, 1H), 7.44 - 7.25 (m, 1H), 7.11 (dd, =8.8, 3.2 Hz, 1H), 3.76 (d, J=6.5 Hz, 2H), 2.17 - 2.06 (m, 1H), 1.05 (d, =6.8 Hz, 6H).
Figure imgf000028_0001
Figure imgf000028_0002
To a dry 250 mL r.b. flask equipped with a large stir bar was added 2-bromo-5- isobutoxypyridine (12.7 g, 55.2 mmol). The flask was placed under N2 atm (vac/fill x 3), then to the flask was added THF (97 ml) and triisopropyl borate (12.9 ml, 55.7 mmol). The solution was degassed with N2 2x and cooled in a -78 °C bath. To the solution was added dropwise n-butyllithium in hexanes (22.3 ml, 55.7 mmol) at a rate necessary to avoid build-up of any localized dark discoloration (usually visible in the central vortex with fast stirring). The rate was approximately 0.25-0.50 mL/min. At the completion of the addition, the solution slowly began to turn dark yellow. Stirring was maintained for 20 min upon which the solution was observed to be a light amber. The bath was removed and the solution was allowed to warm to r.t. with stirring. As the solution warmed, the color deepened even more significantly. After 3 h the reaction solution was carried forward into the distillation step.
The distillation setup:
A 3-neck 250 mL flask equipped with a large stir bar was charged with
methyliminodiacetic acid (16.24 g, 110 mmol) and DMSO (97 ml). The center neck was fitted with a pressure-equalizing addition funnel vented to positive N2 pressure. Another neck was fitted with a rubber septum through which a thermocouple was inserted to monitor internal temperature. The final neck was fitted with a short-path distillation aparatus collecting in a 100 mL r.b. flask and vented to a bubbler. This provides a slow stream of N2 carrier gas through the setup and out through the bubbler so that THF vapor does not accumulate.
Distillation:
The reaction solution containing the boronate was transfered to the addition funnel. The 3-neck flask was heated with an oil bath (160 °C). Once the internal temperature had reached 115-120 °C the boronate solution was added dropwise at a rate necessary to maintain an internal temp of 115-120 °C. The addition took approximately 20 min. The receiver flask containing the THF was exchanged for an empty 100 mL r.b. flask. The bubbler line connected to the vacuum arm of the distillation apparatus was exchanged for a tube running to the rotovap. The N2 source was closed. The system was placed under vacuum, slowly ramping upon at which the DMSO distilled. The distillation was maintained until only trace DMSO remained. The residue was dissolved in MeCN upon which only the MIDA (white powder) did not dissolve. The mixture was concentrated onto celite in vacuo. The resulting powder was subjected to S1O2 purification on the Biotage (0- 100% EtOAc/ACN gradient over 10 CVs). TLC was performed with 1 : 1 EA/ACN looking at it with both ETV and then KMn04 staining (to observe biproduct). The fractions containing the product were collected and concentrated to afford the desired product 2-(5- isobutoxypyridin-2-yl)-6-methyl-l,3,6,2-dioxazaborocane-4,8-dione (7.3 g, 23.85 mmol, 43.2 % yield) as a white solid. LCMS Method 5: retention time = 1.35 min.; observed ion = 307.2. ¾ NMR (500 MHz, Acetone) d 8.45 - 8.38 (m, 1H), 7.60 - 7.54 (m, 1H), 7.29 (dd, =8.4, 2.9 Hz, 1H), 4.34 (d, J=\6.6 Hz, 2H), 4.17 (d, J=\6.6 Hz, 2H), 3.90 - 3.84 (m, 2H), 2.78 (s, 3H), 2.15 - 2.09 (m, 1H), 1.05 (d, =6.8 Hz, 6H).
General Procedure D
Figure imgf000029_0001
To a 5 mL microwave vial equipped with a stir bar was added tripotassium phosphate ( 0.480 mmol), Pd(Ph3P)4 ( 0.019 mmol), 2-(5-isobutoxypyridin-2-yl)-6-methyl- l,3,6,2-dioxazaborocane-4,8-dione compound contaminated with 2-butyl-6-methyl-l, 3,6,2- dioxazaborocane-4,8-dione (0.144 mmol), the appropriate 5-bromopyridine core ( 0.096 mmol), diacetoxycopper (0.048 mmol) and diethanolamine ( 0.096 mmol). The vial was sealed and degassed with N2 (vac/fill x 3). Then to the vial was added DMF (1 ml) and was placed in a 100 °C heating block and stirred for 16 hr (overnight). The reaction was purified on silica gel (Biotage, 24g column, EtO Ac/hexanes gradient, 0-100% over 10 CVs) to give the ester intermediate. This material was taken up in ethanol (2 mL) and treated with sodium hydroxide (0.100 ml, 0.500 mmol, 5 N aq) in a 2 dram pressure relief vial at rt. The reaction was then placed in 100 °C heating block and allowed to stir until hydrolysis was complete as deemed by LCMS (3 hr). The sample was then purified prep- HPLC to afford the corresponding carboxylic acid.
In some cases, pairs of diastereomers were isolated but which was which was not determined and so the flat structure is shown twice, for example, Examples 9 and 10.
General Procedure D was used for Examples 1 - 23
Representative ¾ NMR; Example 1: ¾ NMR (500 MHz, DMSO-de) d 8.33 (br s, 1H), 8.11 (s, 1H), 7.48 (br d, =8.5 Hz, 1H), 7.40 (d, =8.5 Hz, 1H), 5.86 (br s, 1H), 3.92 - 3.82 (m, 2H), 2.56 - 2.53 (m, 2H), 2.49 - 2.45 (m, 3H), 2.05 (dt, =l3.3, 6.5 Hz, 2H), 1.78 (br s,
2H), 1.66 (br s, 4H), 1.45 (br s, 3H), 1.38 (br s, 1H), 1.23 (s, 1H), 1.11 (s, 9H), 1.00 (br d, =6.4 Hz, 6H)
Figure imgf000030_0001
Figure imgf000031_0001
Figure imgf000032_0001
Figure imgf000033_0001
Figure imgf000034_0003
Figure imgf000034_0001
To a 40 mL vial equipped with a stir bar was added l-(2-bromoethyl)-4- fluorobenzene (2.334 g, 11.49 mmol) and 6-bromopyri din-3 -ol (1.00 g, 5.75 mmol), then DMSO (30 ml) and potassium carbonate (1.589 g, 11.49 mmol). The vial was vented to a N2 stream (bubbler), then placed in a 50 °C oil bath with stirring for 18h. (t=0). To the reaction solution was added l-(2-bromoethyl)-4-fluorobenzene (2.334 g, 11.49 mmol). The mixture was stirred at 50 °C for 3h. To the reaction mixture was added potassium carbonate (1.589 g, 11.49 mmol). The reaction mixture was stirred for 18h. The reaction mixture was cooled to r.t., then was transfered to a 500 mL separatory funnel and was diluted with water (150 mL). The mixture was extracted with Et20 (100 mL). The organic phase was washed with brine (50 mL), then dried over MgSCri, filtered, then concentrated in vacuo. The resulting residue was dissolved in a min. of acetone and then was concentrated onto Celite in vacuo. The resulting powder was subjected to S1O2 purification (80g S1O2, hexanes:EtOAc 100:0^80:20) to afford a colorless oil that crystallized upon standing to afford 2-bromo-5-(4-fluorophenethoxy)pyridine (1.5337 g, 90 %) as a colorless, crystalline solid. ¾ NMR (500MHz, CDCh) d 8.04 (d, J=3.0 Hz, 1H), 7.36 (dd, =8.7, 0.5 Hz, 1H), 7.26 - 7.21 (m, 2H), 7.08 (dd, =8.8, 3.2 Hz, 1H), 7.05 - 6.99 (m, 2H), 4.18 (t, =6.8 Hz, 2H), 3.08
Figure imgf000034_0002
To a dry 50 mL Schlenk flask equipped with a large stir bar was added 2-bromo-5- (4-fluorophenethoxy)pyridine (6.103 g, 20.61 mmol). The flask was placed under nitrogen atmosphere. To the flask was added THF (36 ml) and triisopropyl borate (4.83 ml, 20.8 mmol). The flask was sealed with a septum, then the solution was sparged with N2 for 5 minutes. The flask was cooled in a -78 °C bath. To the solution was added dropwise n- butyllithium in hexanes (8.33 ml, 20.8 mmol) at a rate necessary to avoid build-up of any localized dark discoloration. The rate was approximately 0.25-0.50 mL/min. At the completion of the addition the solution slowly began to turn a deep amber color. The mixture was stirred for lh up which the solution was observed to be a deep amber color. The bath was removed and the solution was allowed to warm to r.t. with stirring for 3h. Separately, a distillation apparatus was assembled as follows: a 3-neck 250 mL flask equipped with a large stir bar was charged with methyliminodiacetic acid (6.06 g, 41.2 mmol) and DMSO (36.2 ml); the center neck was fitted with a pressure-equalizing addition funnel vented to positive N2 pressure; another neck was fitted with a rubber septum through which a thermocouple was inserted to monitor internal temperature; and the final neck was fitted with a short-path distillation aparatus collecting into a 250 mL r.b. flask and vented to a bubbler. The reaction solution containing the boronate was transfered to the addition funnel. The 3-neck flask was heated with an oil bath (160 °C). Once the internal temperature had reached 115-120 °C, the boronate solution was added dropwise at a rate necessary to maintain an internal temp of 115-120 °C. The addition took approximately 20 min. The receiver flask containing the THF was exchanged for an empty 200 mL r.b. flask. The bubbler line connected to the vacuum arm of the distillation apparatus was exchanged for a tube running vacuum. The N2 source was closed. The system was placed under vacuum, slowly ramping to 30 Torr upon which the DMSO distilled. The distillation was maintained at 30 Torr until only trace DMSO remained. The resulting residue, a solid, was dissolved in MeCN upon which only a white powder did not dissolve. The mixture was concentrated onto Celite in vacuo. The resulting powder was subjected to S1O2 purification (l20g S1O2 column, EtOAc:MeCN 100:0^0: 100) on the Biotage to afford 2-(5-(4- fluorophenethoxy)pyridin-2-yl)-6-methyl-l,3,6,2-dioxazaborocane-4,8-dione (2.067 g,
27.0 %) as a colorless solid foam. ¾ NMR (500 MHz, acetone-d6) d 8.40 - 8.36 (m, 1H), 7.57 - 7.52 (m, 1H), 7.44 - 7.35 (m, 2H), 7.29 (dd, J=8.4, 2.8 Hz, 1H), 7.12 - 7.02 (m, 2H), 4.31 (d, J=l6.6 Hz, 2H), 4.30 (t, J=6.7 Hz, 2H), 4.14 (d, J=l6.6 Hz, 2H), 3.11 (t, J=6.7 Hz, 2H), 2.75 (s, 3H). General Procedure E
Figure imgf000036_0001
To a 5 mL microwave vial equipped with a stir bar was added tripotassium phosphate (0.480 mmol), Pd(Ph3P)4 (0.019 mmol), 2-(5-(4-fluorophenethoxy)pyridin-2-yl)- 6-methyl-l,3,6,2-dioxazaborocane-4,8-dione (0.136 mmol), the appropriate 5- bromopyridine core ( 0.096 mmol), diacetoxycopper (8.72 mg, 0.048 mmol) and diethanolamine (0.096 mmol). The vial was sealed and degassed with N2 (vac/fill x 3). Then to the vial was added DMF (1 ml) and was placed in a 100 °C heating block, and stirred for 16 hr overnight. The reaction was purified on silica gel (Biotage, 24g column, EtOAc/hexanes gradient, 0-100% over 10 CVs) to give the ester intermediate. This material was taken up in ethanol (2 mL) and treated with sodium hydroxide (0.100 ml, 0.500 mmol, 5 N aq) in a 2-dram pressure relief vial at rt. The reaction was then placed in 100 °C heating block and allowed to stir until hydrolysis was complete as deemed by LCMS (3 hr). The sample was then purified by prep-HPLC to afford the corresponding carboxylic acid.
General Procedure E was used for Examples 24 - 33 Representative Ή NMR; Example 24: Ή NMR (500 MHz, METHANOL-dr) d 8.32 (d, J=2.7 Hz, 1H), 8.15 (s, 1H), 7.52 (dd, J=8.7, 2.9 Hz, 1H), 7.42 - 7.35 (m, 3H), 7.08 - 7.03 (m, 2H), 5.83 (s, 1H), 4.35 (t, J=6.3 Hz, 2H), 3.15 (t, =6.6 Hz, 2H), 2.74 (br s, 2H), 2.65 (s, 3H), 1.92 - 1.85 (m, 2H), 1.78 - 1.62 (m, 10H), 1.19 (s, 9H)
Figure imgf000037_0001
Figure imgf000038_0002
Figure imgf000038_0001
To a 1L round bottom flask equipped with a large stir bar was added 6- bromopyri din-3 -ol (24.69 g, 142 mmol), benzyl alcohol (15.42 mL, 149 mmol), triphenylphosphine (39.1 g, 149 mmol) and THF (600 mL). The flask was placed in a r.t. water bath. To the stirred solution was added in six portions DIAD (29.0 mL, 149 mmol). The internal temperature increased from 20 deg to 35 deg C, and was 35 deg C at the completion of the addition. After stirring for 18 h the reaction solution was concentrated in vacuo to afford a liquid residue. The material was diluted with hexane:Et20 (1 :1, 850 mL). A precipitate was immediately formed. The mixture was stirred for 5 minutes, then the liquid was decanted and reserved. The solids were treated with Et20 (200 mL), and the mixture was stirred for 5 minutes. The solution was diluted with hexanes (200 mL), and the mixture was then stirred for 5 minutes. The mixture and the reserved solution were combined and filtered through a fine-fritted vacuum funnel. The filtrate was concentrated in vacuo. The resulting residue was diluted with a small amount of acetone and then concentrated onto Celite in vacuo. The resulting powder was subjected to Si02
chromatography (330g Si02 column, hexanes:EtOAc 100:0 - 80:20) to afford 5- (benzyloxy)-2-bromopyridine as a colorless, crystalline solid (24.84 g, 66%). 'H NMR (400 MHz, CHLOROFORM-d) d 8.16 (d, J=3.2 Hz, 1H), 7.45 - 7.36 (m, 6H), 7.18 (dd, .7=8.6, 3.2 Hz, 1H), 5.12 (s, 2H).
Alternative procedure : To a stirred solution of 6-bromopyridin-3-ol (100 g, 575 mmol), K2CCh (119 g, 862 mmol) in acetone (1 L) was added benzyl bromide (0.075 L,
632 mmol). The mxiture was stirred for 3 h at 80 °C. LCMS showed completion of reaction. Then, the mixture was cooled to 20 °C and poured into water (250 mL). The precipitate was filtered, taken up in in DCM and washed with sat. NaHCCh (50 mL), water (50 mL), brine (50 mL) and concentrated to afford 5-(benzyloxy)-2-bromopyridine (120 g, 454 mmol, 79 % yield) as a off-white solid.
Figure imgf000039_0001
To a dry 250 mL round bottom flask equipped with a large stir bar and charged with 5-(benzyloxy)-2-bromopyridine (21.8527 g, 83 mmol) was added THF (150 ml) and triisopropyl borate (19.40 ml, 84 mmol). The flask was sealed with a rubber septum, then the solution was sparged with N2 for 5 min. The flask was cooled in a -78 °C bath. To the solution was added dropwise over 30 min n-butyllithium in hexanes (33.4 ml, 84 mmol). The cold bath was removed and the solution was allowed to slowly warm to r.t. with stirring. After 2 h the solution was transferred to a pressure-equalizing addition funnel. The addition funnel was fitted onto the center neck of a 3-neck 250 mL flask equipped with a large stir bar was charged with N-methyliminodiacetic acid (24.35 g, 165 mmol) and DMSO (150 ml). A side neck was fitted with a thermocouple. The other side neck was fitted with a water-cooled short-path distillation apparatus collecting into a 250 mL round bottom flask and vented to a bubbler. The addition funnel was capped with a gas adapter connected to a low-volume stream of N2 gas. The 3 -neck flask was heated with an oil bath (150 °C). Once the DMSO solution had reached 115-120 °C the boronate solution was added dropwise at a rate necessary to maintain an internal temp of 115-120 °C. The blue boronate solution immediately becomes a red/amber color upon contacting the DMSO solution. The reaction mixture is a deep amber solution. Upon completion of the addition the receiver flask containing THF was exchanged for an empty 200 mL round bottom flask. The bubbler line connected to the vacuum arm of the distillation apparatus was exchanged for a controlled vacuum source. The N2 source feeding into the addition funnel was closed. The system was placed under vacuum, slowly ramping to 30 Torr. The receiver flask was emptied, then the vacuum was slowly ramped to 2 Torr. The bath temperature was set to 125 °C and the pressure was maintained at 2 Torr. When the majority of DMSO had been removed the flask was opened to ambient atmosphere. To the flask was added MeCN (100 mL). Heating was maintained until the solvent had reached reflux, then heating was stopped. To the hot mixture was added Celite. The mixture was concentrated in vacuo to afford a clumpy solid which was subjected to S1O2 chromatography
(EtOAc:MeCN 100:0 - 0: 100) to afford the desired product as a colorless solid. This material was dissolved/suspended in MeCN (100 mL), then was diluted with Et20 (400 mL). The crystalline solid was collected via vacuum filtration. The solids were dried under high vacuum to afford (5-(benzyloxy)pyridin-2-yl)boronic acid MIDA ester as a colorless, fine crystalline solid (5.81 g, 21%). ¾ NMR (500 MHz, ACETONITRILE-ds) d 8.50 - 8.42 (m, 1H), 7.56 (d, =8.4 Hz, 1H), 7.49 - 7.44 (m, 2H), 7.44 - 7.38 (m, 2H), 7.38 - 7.33 (m, 1H), 7.31 (dd, =8.4, 2.9 Hz, 1H), 5.16 (s, 2H), 4.10 - 4.04 (m, 2H), 3.98 - 3.92 (m,
2H), 2.54 (s, 3H).
Simplified procedure: To a solution of 5-(benzyloxy)-2-bromopyridine (98 g, 371 mmol) and triisopropyl borate (77 g, 408 mmol) in THF (800mL) was added n- butyllithium (193 mL, 482 mmol) at -78 °C and stirred for 20 min at -78°C. Then, the reaction mixture was stirred at rt for 3 h. The reaction mixture was added to a solution of 2,2'-(2,2'-(methylazanediyl)diacetic acid (109 g, 742 mmol) in DMSO (800 mL) at 115- 120 °C (internal temperature). Then, the THF and DMSO was distilled off over 2 h to remove as much solvent as possible. The reaction flask was cooled, diluted with 3000 mL of ethyl acetate and washed with water (2000 mL x2), dried and concentrated. The residue was purifeid by silica gel chromatography to give 2-(5-(benzyloxy)pyridin-2-yl)-6-methyl- l,3,6,2-dioxazaborocane-4,8-dione (41 g, 120 mmol, 32.2 % yield) as pale solid.
Example 34
Figure imgf000041_0001
(S)-2-(tert-Butoxy)-2-(5'-fluoro-6'-isobutoxy-6-methyl-4-(7-azaspiro[3.5]nonan-7-yl)-[3,3'- bipyridin]-5-yl)acetic acid
Isopropyl (S)-2-(5-bromo-2-methyl-4-(7-azaspiro[3.5]nonan-7-yl)pyridin-3-yl)-2- (tert-butoxy)acetate (45 mg, 0.096 mmol), 3-fluoro-2-isobutoxy-5-(4,4,5,5-tetramethyl- l,3,2-dioxaborolan-2-yl)pyridine (56.8 mg, 0.193 mmol), SPhos Pd G3 (7.50 mg, 9.63 pmol), K3P04 (61.3 mg, 0.289 mmol) were combined under N2. l,4-Dioxane (1604 pl) and water (321 mΐ) were added under N2. The reaction was stirred at 80 °C. for 1 hr. The reaction was concentrated, adsorbed onto celite and was purified on silica gel (Biotage,
EtO Ac/hexanes gradient) to afford isopropyl (S)-2-(tert-butoxy)-2-(5'-fluoro-6'-isobutoxy- 6-methyl-4-(7-azaspiro[3.5]nonan-7-yl)-[3,3'-bipyridin]-5-yl)acetate. The ester was subjected to hydrolysis conditions: (1.5 mL of EtOH, 0.1 mL of 5N aq NaOH, l00°C, 3 hrs.). The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5'-fluoro-6'-isobutoxy-6-methyl-4-(7- azaspiro[3.5]nonan-7-yl)-[3,3'-bipyridin]-5-yl)acetic acid (6.5 mg). LCMS (M + H) = 514.2; Retention time (10 mM NEEITCCh) = 2.10.
Example 35
Figure imgf000041_0002
(S)-2-tert-Butoxy-2-(5-(2-(2-chlorophenoxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-
6'-methyl-2,3'-bipyridin-5'-yl)acetic acid:
Step 1 : To a solution of 2-(2-chlorophenoxy)ethan-l-ol (1.2 g, 6.95 mmol) and TEA (2.91 mL, 20.86 mmol) in THF (20 mL) was added dropwise Ms-Cl (0.813 mL,
10.43 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. LCMS showed that SM was consumed completely. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NalTCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S04, filtered and concentrated to give 2-(2-chlorophenoxy)ethyl methanesulfonate (l . lg, 4.39 mmol, 63.1 % yield)as a brown oil which was used in the next step without purification.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.103 mmol) in DMF (10 mL), 2-(2-chlorophenoxy)ethyl methanesulfonate (78 mg, 0.310 mmol) and was adde K2CO3 (71.4 mg, 0.517 mmol) and the mixture was stirred for 20 hours at 45 °C. The mixture was diluted with water and ethyl acetate (30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2- (2-chlorophenoxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]- 5'-yl)acetate (53 mg, 0.083 mmol, 80 % yield) as a yellow oil. LCMS (M + H) = 683.1; Retention time (10 mM NLLHCCh) = 2.569.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetate (53 mg, 0.083 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.96 mg, 0.249 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC
(Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetic acid (24.6 mg, 0.041 mmol, 49.7 % yield) as white solid. LCMS (M + H) = 596.1; Retention time (10 mM NH4HCO3) = 1.604. ¾ NMR (400 MHz, MeOD) d 8.46 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.69 (dd, J = 8.6, 3.0 Hz, 1H), 7.49 (d, J = 8.6 Hz, 1H), 7.38 (dd, J = 7.9, 1.6 Hz, 1H), 7.33- 7.26 (m, 1H), 7.17 (dd, J = 8.3, 1.3 Hz, 1H), 6.97 (td, J = 7.7, 1.4 Hz, 1H), 5.81 (s, 1H), 4.59 (dd, J = 8.0, 3.8 Hz, 2H), 4.49- 4.45 (m, 2H), 3.3- 2.81 (m, 7H), 1.61- 1.26 (m, 6H), 1.21 (s, 9H), 0.84- 0.75 (m, 6H).
Example 36
Figure imgf000043_0001
(S)-2-tert-Butoxy-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-(2-phenoxy ethoxy)-
2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of 2-phenoxyethan-l-ol (1 g, 7.24 mmol) and TEA (3.03 mL, 21.71 mmol) in THF (20 mL) was added dropwise Ms-Cl (0.846 mL, 10.86 mmol)at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. LCMS showed that SM was consumed completely. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaHCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S04, filtered and concentrated to give 2-phenoxy ethyl methanesulfonate (900 mg, 4.16 mmol, 57.5 % yield) as a brown oil which was used in the next step without purification.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.103 mmol) in DMF (10 mL) was added K2CO3 (71.4 mg, 0.517 mmol) and 2-phenoxyethyl methanesulfonate (67.1 mg, 0.310 mmol). Then, the mixture was stirred at 45 °C for 20 hours and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04, concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'- methyl-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.057 mmol, 55.1 % yield) as a yellow oil. LCMS (M + H) = 604.2; Retention time (10 mM NH4HCO3) =
2.513.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.084 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.13 mg, 0.253 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate ( 5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'- methyl-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (10.9 mg, 0.019 mmol, 22.97 % yield). LCMS (M + H) = 562.2; Retention time (10 mM NH4HCO3) = 1.648. ¾ NMR (400 MHz, MeOD) d 8.33 (d, J = 2.8 Hz, 1H), 8.06 (s, 1H), 7.53 (dd, J = 8.6, 2.9 Hz, 1H), 7.38 (d, j = 8.6 Hz, 1H), 7.23- 7.14 (m, 2H), 6.91- 6.81 (m, 3H), 5.70 (s, 1H), 4.40 (dd, j= 6.1, 3.0 Hz, 2H), 4.32- 4.24 (m, 2H), 3.30- 2.54 (m, 7H), 1.54 -1.17 (m, 6H), 1.09 (s, 9H), 0.75- 0.65 (m, 6H).
Example 37
Figure imgf000044_0001
(S)-2-tert-Butoxy-2-(5-butoxy-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-2,3'- bipyridin-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.103 mmol) in DMF (10 mL) was added K2CO3 (14.29 mg, 0.103 mmol) and l-bromobutane (14.17 mg, 0.103 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product, which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-butoxy-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl- [2,3'-bipyridin]-5'-yl)acetate (43 mg, 0.080 mmol, 77 % yield) as a yellow oil. LCMS (M + H) = 540.2; Retention time (10 mM NH4HCO3) = 2.758.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-butoxy-4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.096 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (1 1.56 mg, 0.289 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG- 009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5-butoxy-4'-(4-ethyl-4-methylpiperidin-l- yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetic acid (21.6 mg, 0.042 mmol, 43.9 % yield) as white solid. LCMS (M + H) = 498.1; Retention time (10 mM NH4HCO3) = 1.716. Ή NMR (400 MHz, MeOD) d 8.36 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.56 (dd, J = 8.6, 2.9 Hz, 1H), 7.47 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.16 (t, J = 6.4 Hz, 2H), 2.30- 2.66 (m, 7H), 1.91- 1.77 (m, 2H), 1.64- 1.25 (m, 8H), 1.21 (s, 9H), 1.04 (t, J = 7.4 Hz, 3H), 0.88- 0.77
(m, 6H).
Example 38
Figure imgf000045_0001
(S)-2-tert-Butoxy-2-(5-(2-(l,3-dimethyl-lH-pyrazol-4-yl)ethoxy)-4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of 2-(l,3-dimethyl-lH-pyrazol-4-yl)ethan-l-ol (250 mg, 1.783 mmol) and triethylamine (271 mg, 2.68 mmol) in DCM (10 mL) was added methanesulfonyl chloride (225 mg, 1.962 mmol) at 0 °C . The mixture was stirred at rt for 1 h. The mixture was taken up into aqueous Na2C03 (20 mL) and extracted with DCM (10 ml X 3). The combined organic layers were washed with brine, dried over Na2S04, concentrated to afford 2-(l,3-dimethyl-lH-pyrazol-4-yl)ethyl methanesulfonate (300 mg, 1.100 mmol, 61.7 % yield) as oil which was used in the next step without further purification. LCMS: retention time = 1.22 min, m/z = 219 [M+H]+, purity: 80% (214 nm).
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.103 mmol) in DMF (10 mL) was added K2CO3 (71.4 mg, 0.517 mmol) and 2-(l,3-dimethyl- lH-pyrazol-4-yl)ethyl methanesulfonate (67.7 mg, 0.310 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product, which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2- (l,3-dimethyl-lH-pyrazol-4-yl)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'- bipyridin]-5'-yl)acetate (41 mg, 0.068 mmol, 65.5 % yield) as a yellow oil. LCMS (M + H) = 606.2; Retention time (10 mM NH4HCO3) = 2.234.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetate (41 mg, 0.068 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.12 mg, 0.203 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5-(2-(l,3- dimethyl-lH-pyrazol-4-yl)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'- bipyridin]-5'-yl)acetic acid (17.3 mg, 0.031 mmol, 45.3 % yield) as white solid. LCMS (M + H) = 564.2; Retention time (10 mM NH4HCO3) = 1.452. ¾ NMR (400 MHz, MeOD) d 8.38 (d, J = 2.7 Hz, 1H), 8.16 (s, 1H), 7.56 (dd, J = 8.6, 2.9 Hz, 1H), 7.47 (d, J = 7.8 Hz, 2H), 5.82 (s, 1H), 4.25 (t, J = 6.7 Hz, 2H), 3.80 (s, 3H), 3.23- 2.57 (m, 9H), 2.25 (s, 3H), 1.61-1.23 (m, 6H), 1.21 (s, 9H), 0.87- 0.74 (m, 6H).
Example 39
Figure imgf000047_0001
(S)-2-tert-Butoxy-2-(5-(cyclopropylmethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'- methyl-2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l- yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (42.9 mg, 0.310 mmol) and (bromomethyl)cyclopropane (25.1 mg, 0.186 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product, which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)-4'-(4-ethyl-4-methylpiperidin-l- yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.018 mmol, 29.7 % yield) as a yellow oil. LC;MS (M + H) = 538.3; Retention time (10 mM NH4HCO3) = 2.005.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)- 4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.056 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.69 mg, 0.167 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)-4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetic acid (10.1 mg, 0.020 mmol, 36.5 % yield) as white solid. LCMS (M + H) = 496.2; Retention time (10 mM NH4HCO3) = 1.573. ¾ NMR (400 MHz, MeOD) d 8.37 (d, J = 2.7 Hz, 1H), 8.16 (s, 1H), 7.55 (dd, J = 8.6, 2.9 Hz, 1H), 7.46 (d, J = 8.5 Hz, 1H), 5.82 (s, 1H), 4.00 (d, J = 7.0 Hz, 2H), 3.09- 2.53 (m, 7H), 1.58-1.27 (m, 7H), 1.21 (s, 9H), 0.91- 0.76 (m, 6H), 0.73- 0.63 (m, 2H), 0.53- 0.30 (m, 2H). Example 40
Figure imgf000048_0001
(S)-2-tert-Butoxy-2-(5-(cyclobutylmethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-
2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (31 mg, 0.064 mmol) in DMF (10 mL) was added K2CO3 (26.6 mg, 0.192 mmol) and
(bromomethyl)cyclobutane (19.10 mg, 0.128 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product, which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (31 mg, 0.023 mmol, 35.9 % yield) as a yellow oil. LCMS (M + H) = 552.2; Retention time (10 mM NH4HCO3) = 2.237.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-4'- (4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (31 mg, 0.056 mmol) in methanol (10 mL) and water (2 mL) was added NaOH (2.247 mg, 0.056 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG- 009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetic acid (15.9 mg, 0.031 mmol, 55.5 % yield) as white solid. LCMS (M + H) = 510.1; Retention time (10 mM NH4HCO3)
= 1.681. ¾ NMR (400 MHz, MeOD) d 8.37 (d, J = 2.7 Hz, 1H), 8.17 (s, 1H), 7.56 (dd, J = 8.6, 2.9 Hz, 1H), 7.47 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.12 (d, J = 6.5 Hz, 2H), 3.15- 2.54 (m, 7H), 2.19 (ddd, J = 8.6, 7.3, 4.6 Hz, 2H), 2.11- 1.87 (m, 4H), 1.72- 1.22 (m, 6H), 1.21 (s, 9H), 0.92- 0.73 (m, 6H).
Example 41
Figure imgf000049_0001
(S)-2-tert-Butoxy-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-5-(2-isopropoxyethoxy)-6'- methyl-2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) and K2CO3 (42.9 mg, 0.310 mmol) was added 2-(2- bromoethoxy)propane (31.1 mg, 0.186 mmol). The mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)- 5-(2-isopropoxyethoxy)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (26 mg, 0.019 mmol,
30.6 % yield) as a yellow oil. LCMS (M + H) = 570.5; Retention time (10 mM NH4HCO3) = 1.969.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-(2-isopropoxyethoxy)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (26 mg, 0.046 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (5.48 mg, 0.137 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(4'-(4- ethyl-4-methylpiperidin-l-yl)-5-(2-isopropoxyethoxy)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetic acid (14.5 mg, 0.027 mmol, 60.2 % yield) as white solid. LCMS (M + H) = 528.2; Retention time (10 mM MLHCO3) = 1.573. ¾ NMR (400 MHz, MeOD) d 8.41 (d, J = 2.9 Hz, 1H), 8.17 (s, 1H), 7.60 (dd, J = 8.6, 2.9 Hz, 1H), 7.48 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.28 (dd, J = 5.6, 3.2 Hz, 2H), 3.91- 3.83 (m, 2H), 3.75 (dt, J = 12.2, 6.1 Hz, 1H), 3.30-2.82 (m, 7H), 1.51-1.50 (m, 2H), 1.42-1.26 (m, 4H), 1.23 (s, 6H), 1.21 (s, 9H), 0.87- 0.79 (m, 6H).
Example 42
Figure imgf000050_0001
(S)-2-tert-Butoxy-2-(5-(2-tert-butoxyethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'- methyl-2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of 2-(tert-butoxy)ethan-l-ol (1 g, 8.46 mmol) and TEA (3.54 mL, 25.4 mmol) in THF (15 mL) was added dropwise Ms-Cl (0.989 mL, 12.69 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. TLC showed that SM was consumed completely. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaHCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S04, filtered and concentrated to give 2-(tert-butoxy)ethyl methanesulfonate (l .2g, 1.352 mmol, 15.98 % yield) as a brown oil which was used in the next step without purification.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added 2-(tert-butoxy)ethyl methanesulfonate (18.26 mg,
0.093 mmol) and K2CO3 (17.15 mg, 0.124 mmol) and stirred for 20 hours at 45 °C. The reaction mixture was diluted with water and ethyl acetate (30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(tert-butoxy)ethoxy)-4'- (4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (40 mg, 0.021 mmol, 34.6 % yield) as a yellow oil. LCMS (M + H) = 584.2; Retention time (10 mM NH4HCC>3) = 2.714.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(tert-butoxy)ethoxy)- 4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (40 mg, 0.069 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.22 mg, 0.206 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5-(2-(tert-butoxy)ethoxy)-4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetic acid (14.9 mg, 0.028 mmol, 40.1 % yield) as white solid. LCMS (M + H) = 542.2; Retention time (10 mM NH4HCO3) = 1.623. ¾ NMR (400 MHz, MeOD) d 8.40 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.60 (dd, J = 8.6, 2.9 Hz, 1H), 7.48 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.26 (dd, J = 7.5, 4.3 Hz, 2H), 3.82 (t, J = 4.6 Hz, 2H), 3.18- 2.45 (m, 7H), 1.60- 1.24 (m, 15H), 1.21 (s, 9H), 0.87- 0.79 (m, 6H).
Example 43
Figure imgf000051_0001
(S)-2-tert-Butoxy-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-(4,4,4- trifluorobutoxy)-2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of 4,4,4-trifluorobutan-l-ol (2 g, 15.61 mmol) and TEA (2.176 mL, 15.61 mmol) in THF (20 mL) was added dropwise Ms-Cl (1.217 mL, 15.61 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaHCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S04, filtered and concentrated to give 4,4,4-trifluorobutyl methanesulfonate (2.5g,
11.52 mmol, 73.8 % yield) as a brown oil which was used in the next step without purification.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added 4,4,4-trifluorobutyl methanesulfonate (12.79 mg, 0.062 mmol) and K2CO3 (8.57 mg, 0.062 mmol) and stirred for 20 hours at 45 °C. Diluted with water and ethyl acetate (30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-(4,4,4- trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate (42 mg, 0.028 mmol, 44.8 % yield) as a yellow oil. LCMS (M + H) = 594.2; Retention time (10 mM NLLHCCh) = 2.652.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate (42 mg, 0.071 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.49 mg, 0.212 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC
(Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'- yl)acetic acid (22.9 mg, 0.042 mmol, 58.7 % yield) as white solid. LCMS (M + H) = 552.2; Retention time (10 mM MLHCO3) = 1.645. ¾ NMR (400 MHz, MeOD) d 8.41 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.59 (dd, J = 8.6, 2.9 Hz, 1H), 7.49 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.24 (t, J = 6.1 Hz, 2H), 3.30- 2.66 (m, 7H), 2.45 (ddd, J = 10.9, 8.0, 5.4 Hz, 2H), 2.12 (dd, J = 10.2, 5.8 Hz, 2H), 1.75- 1.25 (m, 6H), 1.21 (s, 9H), 0.90- 0.74 (m, 6H).
Example 44
Figure imgf000053_0001
(S)-2-tert-Butoxy-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-((tetrahydro-2H- pyran-4-yl)methoxy)-2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of (tetrahydro-2H-pyran-4-yl)methanol (1 g, 8.61 mmol) and TEA (2.400 mL, 17.22 mmol) in THF (15 mL) was added dropwise Ms-Cl (1.006 mL, 12.91 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaElCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S04, filtered and concentrated to give (tetrahydro-2H-pyran-4-yl)methyl
methanesulfonate (1.1 g, 5.21 mmol, 60.6 % yield) as a brown oil which was used in the next step without purification.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and (tetrahydro-2H- pyran-4-yl)methyl methanesulfonate (18.07 mg, 0.093 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product, which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'- bipyridin]-5'-yl)acetate (30 mg, 0.016 mmol, 25.5 % yield) as a yellow oil. LCMS (M + H) = 582.2; Retention time (10 mM NLLHCO3) = 2.747.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]- 5'-yl)acetate (30 mg, 0.052 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.19 mg, 0.155 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep- HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'- bipyridin]-5'-yl)acetic acid (11.8 mg, 0.022 mmol, 42.4 % yield) as white solid. LCMS (M + H) = 540.2; Retention time (10 mM NH4HCO3) = 1.509. ¾ NMR (400 MHz, MeOD) d 8.38 (d, J = 2.7 Hz, 1H), 8.16 (s, 1H), 7.57 (dd, J = 8.6, 2.9 Hz, 1H), 7.48 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.16- 3.85 (m, 4H), 3.51 (t, J = 10.9 Hz, 2H), 3.30- 2.65 (m, 7H), 2.24- 2.07 (m, 1H), 1.83 (d, J = 12.0 Hz, 2H), 1.57- 1.27 (m, 8H), 1.21 (s, 9H), 0.88- 0.76 (m, 6H).
Example 45
Figure imgf000054_0001
(2S)-2-tert-Butoxy-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-((tetrahydrofuran-3- yl)methoxy)-2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of (tetrahydrofuran-3-yl)methanol (1 9, 9.79 mmol) and TEA (1.365 mL, 9.79 mmol) in THF (15 mL) was added dropwise Ms-Cl (0.763 mL, 9.79 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaElCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S04, filtered and concentrated to give (tetrahydrofuran-3-yl)methyl methanesulfonate (l.2g, 5.92 mmol, 60.5 % yield) as a brown oil which was used in the next step without purification.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and (tetrahydrofuran-3- yl)methyl methanesulfonate (22.36 mg, 0.124 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product, which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'-bipyridin]-5'- yl)acetate (35 mg, 0.019 mmol, 31.0 % yield) as a yellow oil. LCMS (M + H) = 568.2; Retention time (10 mM NH4HCO3) = 2.451.
Step 3 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'-bipyridin]-5'- yl)acetate (35 mg, 0.062 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (7.40 mg, 0.185 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'- bipyridin]-5'-yl)acetic acid (15.2 mg, 0.029 mmol, 46.9 % yield) as white solid. LCMS (M + H) = 526.2; Retention time (10 mM NH4HCO3) = 1.472. ¾ NMR (400 MHz, MeOD) d 8.39 (d, J = 2.7 Hz, 1H), 8.16 (s, 1H), 7.58 (dd, J = 8.6, 2.9 Hz, 1H), 7.48 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.19- 4.04 (m, 2H), 3.95 (dt, J = 14.5, 7.4 Hz, 2H), 3.84- 3.69 (m, 2H), 3.23- 2.59 (m, 8H), 2.26- 2.11 (m, 1H), 1.84 (dt, J = l2.9, 7.2 Hz, 1H), 1.65- 1.25 (m, 6H), 1.21 (s, 9H), 0.88- 0.77 (m, 6H).
Example 46
Figure imgf000055_0001
(S)-2-tert-Butoxy-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-(2-(tetrahydro-2H- pyran-4-yl)ethoxy)-2,3'-bipyridin-5'-yl)acetic acid Step 1 : To a solution of 2-(tetrahydro-2H-pyran-4-yl)ethan-l-ol (300 mg, 2.304 mmol) and TEA (0.964 mL, 6.91 mmol) in THF (10 mL) was added dropwise Ms-Cl (0.269 mL, 3.46 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaHCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S04, filtered and concentrated to give 2-(tetrahydro-2H-pyran-4-yl)ethyl methanesulfonate (300 mg, 1.329 mmol, 57.7 % yield) as a brown oil which was used in the next step without purification.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (40 mg, 0.083 mmol) in DMF (10 mL) was added K2CO3 (34.3 mg, 0.248 mmol) and 2-(tetrahydro-2H- pyran-4-yl)ethyl methanesulfonate (25.8 mg, 0.124 mmol). The mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product, which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin- l-yl)-6'-methyl-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.020 mmol, 24.77 % yield) as a yellow oil. LCMS (M + H) = 596.5; Retention time (10 mM MLHCCb) = 2.293.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]- 5'-yl)acetate (51 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep- HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'- bipyridin]-5'-yl)acetic acid (19.0 mg, 0.032 mmol, 37.7 % yield) as white solid. LCMS (M + H) = 554.2; Retention time (10 mM NH4HCO3) = 1.545. ¾ NMR (400 MHz, MeOD) d 8.37 (d, J = 2.7 Hz, 1H), 8.17 (s, 1H), 7.57 (dd, J = 8.6, 2.9 Hz, 1H), 7.48 (d, J = 8.6 Hz, 1H), 5.83 (s, 1H), 4.23 (t, J = 6.2 Hz, 2H), 3.97 (dd, J = 11.4, 3.6 Hz, 2H), 3.47 (td, J = 11.8, 2.0 Hz, 2H), 3.30-2.65 (m, 7H), 1.96-1.68 (m, 5H), 1.40-1.39 (m, 8H), 1.21 (s, 9H), 0.90- 0.77 (m, 6H).
Example 47
Figure imgf000057_0001
(S)-2-tert-Butoxy-2-(5-(2,2-difluorobutoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-
2,3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and l-bromobutan-2- one (18.73 mg, 0.124 mmol). Then, the mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product, which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-6'- methyl-5-(2-oxobutoxy)-[2,3'-bipyridin]-5'-yl)acetate (15 mg, 0.027 mmol, 43.7 % yield) as a yellow oil. LCMS (M + H) = 554.4; Retention time (0.0l%TFA) = 2.168.
Step 2: The mixture of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-5-(2-oxobutoxy)-[2, 3'-bipyridin]-5'-yl)acetate (15 mg, 0.027 mmol) and DAST (5 mL) was stirred for 20 hours at 20 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04, concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-4'-(4-ethyl-4-methylpiperidin-l- yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (8 mg, 0.014 mmol, 51.3 % yield) as a yellow oil. LCMS (M + H) = 576.3; Retention time (0.0l%TFA) = 2.184.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-4'- (4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (8 mg, 0.014 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (1.667 mg, 0.042 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and extracted with ethyl acetate (5 ml). Organic layer concentrated and purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM
NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-4'-(4-ethyl-4- methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'-yl)acetic acid (3.3 mg, 6.18 pmol,
44.5 % yield) as white solid. LCMS (M + H) = 534.2; Retention time (10 mM NH4HCO3)
= 1.611. ¾ NMR (400 MHz, MeOD) d 8.45 (d, J = 2.8 Hz, 1H), 8.14 (s, 1H), 7.64 (dd, J = 8.6, 3.0 Hz, 1H), 7.50 (d, J = 8.6 Hz, 1H), 5.80 (s, 1H), 4.41 (t, J = 12.0 Hz, 2H), 3.31- 2.65 (m, 7H), 2.26- 2.01 (m, 2H), 1.68- 1.25 (m, 6H), 1.20 (s, 9H), 1.12 (t, J = 7.5 Hz, 3H), 0.88-0.75 (m, 6H).
Example 48
Figure imgf000058_0001
(S)-2-tert-Butoxy-2-(5-(2-(cyclopentyloxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'- methyl-2, 3'-bipyridin-5'-yl)acetic acid
Step 1 : To a solution of 2-(cyclopentyloxy)ethan-l-ol (1 g, 7.68 mmol) and TEA (2.141 mL, 15.36 mmol) in THF (l5 mL) was added dropwise Ms-Cl (0.898 mL, 11.52 mmol) at 0 °C. The reaction mixture was stirred for 20 hours at 25 °C. The reaction mixture was poured into water (20 mL), extracted by EtOAc (30 mL), washed with 1M HC1 (5 ml), sat NaElCCh, (10 ml) and brine (10 ml). The organic layer was dried over Na2S04, filtered and concentrated to give 2-(cyclopentyloxy)ethyl methanesulfonate (l .07g, 4.62 mmol, 60.2 % yield) as a brown oil which was used in the next step without purification.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and 2- (cyclopentyloxy)ethyl methanesulfonate (15.50 mg, 0.074 mmol). The mixture was stirred for 20 hours at 45 °C and diluted with water and ethyl acetate (30 mL). Organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetate (30 mg, 0.046 mmol, 73.8 % yield) as a yellow oil. LCMS (M + H) = 596.4; Retention time (10 mM NH4HCO3) = 2.252.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetate (30 mg, 0.050 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.04 mg, 0.151 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-4'-(4-ethyl-4-methylpiperidin-l-yl)-6'-methyl-[2,3'-bipyridin]-5'- yl)acetic acid (14.4 mg, 0.026 mmol, 51.6 % yield) as white solid. LCMS (M + H) = 554.2; Retention time (10 mM NFLHCCh) = 1.654. ¾ NMR (400 MHz, MeOD) d 8.40 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.60 (dd, J = 8.6, 2.9 Hz, 1H), 7.48 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.28 (td, J = 3.9, 1.5 Hz, 2H), 4.11- 4.01 (m, 1H), 3.86-3.78 (m, 2H),3.30- 2.66 (m, 7H), 1.83-1.67 (m, 6H), 1.62-1.44 (m, 4H), 1.41 -1.27 (m, 4H), 1.21 (s, 9H), 0.88- 0.79 (m, 6H).
Example 49
Figure imgf000059_0001
(S)-2-(tert-Butoxy)-2-(5-butoxy-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-
5'-yl)acetic acid Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 ( 13.94 mg, 0.101 mmol) and 1 -bromobutane (13.82 mg, 0.101 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04, concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-butoxy-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'- bipyridin]-5'-yl)acetate (44 mg, 0.080 mmol, 79 % yield) as yellow oil. LCMS (M + H) = 552.2; Retention time (10 mM NH4HCO3) = 2.905 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-butoxy-6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (46 mg, 0.083 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.00 mg, 0.250 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert-butoxy)-2-(5-butoxy-6'- methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (13.1 mg, 0.026 mmol, 30.8 % yield) as white solid. LCMS (M + H) = 510.1; Retention time (10 mM NH4HCO3) = 1.736 min. ¾NMR (400 MHz, MeOD) d 8.36 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.55 (dd, J = 8.6, 2.9 Hz, 1H), 7.45 (d, J = 8.5 Hz, 1H), 5.84 (s, 1H), 4.16 (t, J = 6.4 Hz, 2H), 3.30- 2.66 (m, 7H), 1.88- 1.83 (m, 2H), 1.64- 1.32 (m, 14H), 1.21 (s, 9H), 1.03- 1.02 (m, 2H).
Example 50
Figure imgf000060_0001
(S)-2-(tert-Butoxy)-2-(5-(2-(2-chlorophenoxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-
8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-(2-chlorophenoxy)ethyl
methanesulfonate (76 mg, 0.303 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'- yl)acetate (54 mg, 0.079 mmol, 79 % yield). LCMS (M + H) = 650.0; Retention time (10 mM NH4HCO3) = 2.638 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'- yl)acetate (54 mg, 0.083 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.96 mg, 0.249 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NLLHCCh); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert-butoxy)-2-(5-(2-(2-chlorophenoxy)ethoxy)-6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (16.7 mg, 0.027 mmol, 33.1 % yield) as white solid. LCMS (M + H) = 608.1; Retention time (10 mM NH4HCO3) = 1.619 min. ¾NMR (400 MHz, MeOD) d 8.46 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.69 (dd, J = 8.6, 2.9 Hz, 1H), 7.48 (d, J = 8.6 Hz, 1H), 7.38 (dd, J = 7.9, 1.6 Hz, 1H), 7.33- 7.24 (m, 1H), 7.17 (dd, J = 8.3, 1.3 Hz, 1H), 6.97 (td, J = 7.7, 1.4 Hz, 1H), 5.84 (s, 1H), 4.59 (dd, J = 7.0, 3.7 Hz, 2H), 4.51- 4.44 (m, 2H), 3.30- 2.66 (m, 7H), 1.63- 1.47 (m, 8H), 1.47-1.26 (m,
4H), 1.21 (s, 9H).
Example 51
Figure imgf000062_0001
(S)-2-(tert-Butoxy)-2-(6'-methyl-5-(2-phenoxyethoxy)-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'- bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-phenoxyethyl methanesulfonate (65.4 mg, 0.303 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-5-(2-phenoxyethoxy)-4'-(8-azaspiro[4.5]decan- 8-yl)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.058 mmol, 57.7 % yield). LCMS (M + H) = 616.2; Retention time (10 mM NH4HCO3) = 2.576 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-5-(2- phenoxyethoxy)-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.084 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.13 mg, 0.253 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert- butoxy)-2-(6'-methyl-5-(2-phenoxyethoxy)-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]- 5'-yl)acetic acid (11.9 mg, 0.021 mmol, 24.56 % yield). LCMS (M + H) = 574.2; Retention time (10 mM NH4HCO3) = 1.668 min. ¾NMR (400 MHz, MeOD) d 8.44 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.64 (dd, J = 8.6, 2.9 Hz, 1H), 7.48 (d, J = 8.6 Hz, 1H), 7.35- 7.24 (m, 2H), 6.99 (dt, J = 13.5, 4.1 Hz, 3H), 5.84 (s, 1H), 4.53 (dd, J = 6.0, 2.9 Hz, 2H), 4.44- 4.37 (m, 2H), 3.30- 2.66 (m, 7H), 1.68-1.28 (m, 12H), 1.21 (s, 9H). Example 52
Figure imgf000063_0001
(S)-2-(tert-Butoxy)-2-(5-(2-(l, 3-dimethyl- HT-pyrazol-4-yl)ethoxy)-6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(l,3-dimethyl-lH-pyrazol-4-yl)ethyl methanesulfonate (22.02 mg, 0.101 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (42 mg, 0.068 mmol, 67.4 % yield) as yellow oil. LCMS (M + H) = 618.2; Retention time (10 mM NH4HCO3) = 2.289 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (42 mg, 0.068 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.16 mg, 0.204 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep- HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2- (tert-butoxy)-2-(5-(2-(l, 3-dimethyl- UT-pyrazol-4-yl)ethoxy)-6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (17.5 mg, 0.030 mmol, 44.7 % yield) as white solid. LCMS (M + H) = 576.2; Retention time (10 mM NH4HCO3) = 1.468 min. 1HNMR (400 MHz, MeOD) d 8.37 (d, J = 2.8 Hz, 1H), 8.15 (s, 1H), 7.55 (dd, J = 8.6, 2.9 Hz, 1H), 7.45 (d, J = 9.9 Hz, 2H), 5.84 (s, 1H), 4.26 (t, J = 6.6 Hz, 2H), 3.80 (s, 3H), 3.22 -2.59 (m, 9H), 2.25 (s, 3H), 1.67-1.27 (m, 12H), 1.21 (s, 9H).
Example 53
Figure imgf000064_0001
(S)-2-(tert-Butoxy)-2-(5-(cyclopropylmethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-
[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and bromocyclopropane (21.97 mg, 0.182 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)-6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.018 mmol, 30.4 % yield) as yellow oil. LCMS (M + H) = 550.3; Retention time (10 mM NH4HCO3) = 2.062 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)- 6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.055 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (2.183 mg, 0.055 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC
(Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert- butoxy)-2-(5-(cyclopropylmethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'- bipyridin]-5'-yl)acetic acid (6.2 mg, 0.012 mmol, 22.38 % yield) as white solid. LCMS (M + H) = 508.2; Retention time (10 mM NH4HCO3) = 1.596 min. 1HNMR (400 MHz, MeOD) d 8.36 (d, J = 2.8 Hz, 1H), 8.16 (s, 1H), 7.54 (dd, J = 8.6, 2.9 Hz, 1H), 7.44 (d, J = 8.6 Hz, 1H), 5.85 (s, 1H), 4.01 (d, J = 7.0 Hz, 2H), 3.30- 2.66 (m, 7H), 1.66- 1.27 (m,
13H), 1.21 (s, 9H), 0.72- 0.61 (m, 2H), 0.50- 0.37 (m, 2H).
Example 54
Figure imgf000065_0001
(S)-2-(tert-Butoxy)-2-(5-(cyclobutylmethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-
[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (32 mg, 0.065 mmol) in DMF (10 mL) , K2CO3 (8.92 mg, 0.065 mmol) and bromocyclobutane (8.72 mg, 0.065 mmol) was added. The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)- [2,3'-bipyridin]-5'-yl)acetate (32 mg, 0.014 mmol, 22.19 % yield) as yellow oil. LCMS (M + H) = 564.4; Retention time (10 mM NH4HCO3) = 2.326 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-6'- methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (32 mg, 0.057 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.81 mg, 0.170 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert-butoxy)-2-(5- (cyclobutylmethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (7.7 mg, 0.015 mmol, 26.0 % yield) as white solid. LCMS (M + H) = 522.2; Retention time (10 mM NH4HCO3) = 1.709 min. 1HNMR (400 MHz, MeOD) d 8.36 (d, J = 2.8 Hz, 1H), 8.16 (s, 1H), 7.55 (dd, J = 8.6, 2.9 Hz, 1H), 7.44-7.43 (m, 1H), 5.85 (s, 1H), 4.13 (d, J = 6.6 Hz, 2H), 3.30- 2.66 (m, 7H), 2.27- 1.92 (m, 6H), 1.66- 1.28 (m, 13H), 1.21 (s, 9H).
Example 55
Figure imgf000066_0001
(S)-2-(tert-Butoxy)-2-(5-(2-isopropoxyethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-
[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(2-bromoethoxy)propane (30.3 mg, 0.182 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to isopropyl (S)-2-(tert-butoxy)-2-(5-(2-isopropoxyethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)- [2,3'-bipyridin]-5'-yl)acetate (27 mg, 0.024 mmol, 39.4 % yield) as yellow oil. LCMS (M + H) = 582.5; Retention time (10 mM NH4HCO3) = 2.021 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-isopropoxyethoxy)- 6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (27 mg, 0.046 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (5.57 mg, 0.139 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC
(Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 mhi; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert- butoxy)-2-(5-(2-isopropoxyethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'- bipyridin]-5'-yl)acetic acid (16.1 mg, 0.030 mmol, 64.3 % yield) as white solid. LCMS (M + H) = 540.2; Retention time (10 mM NH4HCO3) = 1.594 min. 1HNMR (400 MHz, MeOD) d 8.40 (d, J = 2.7 Hz, 2H), 8.17 (s, 1H), 7.59 (dd, J = 8.6, 2.9 Hz, 1H), 7.46 (d, J = 8.6 Hz, 1H), 5.85 (s, 1H), 4.32- 4.24 (m, 2H), 3.87 (dd, J = 5.3, 3.8 Hz, 2H), 3.74 (dd, J = 12.2, 6.1 Hz, 1H), 3.30- 2.66 (m, 7H), 1.64- 1.30 (m, 12H), 1.23- 1.21 (m, 15H).
Example 56
Figure imgf000067_0001
(S)-2-(tert-Butoxy)-2-(5-(2-(tert-butoxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-
[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added 2-(tert-butoxy)ethyl methanesulfonate (23.76 mg, 0.121 mmol) and K2CO3 (25.09 mg, 0.182 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(tert-butoxy)ethoxy)-6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (41 mg, 0.023 mmol, 37.2 % yield)as brown oil. LCMS (M + H) = 596.3; Retention time (10 mM NH4HCO3) = 2.794 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2-(tert-butoxy)ethoxy)- 6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (41 mg, 0.069 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.26 mg, 0.206 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC
(Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert- butoxy)-2-(5-(2-(tert-butoxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'- bipyridin]-5'-yl)acetic acid (16 mg, 0.029 mmol, 42.0 % yield) as white solid. LCMS (M + H) = 554.2; Retention time (10 mM NH4HCO3) = 1.643 min. lHNMR (400 MHz, MeOD) d 8.40 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.59 (dd, J = 8.6, 2.9 Hz, 1H), 7.46 (d, J = 8.6 Hz, 1H), 5.85 (s, 1H), 4.31- 4.20 (m, 2H), 3.89-3.76 (m, 2H), 3.30- 2.66 (m, 7H), 1.65- 1.49 (m, 8H), 1.47- 1.31 (m, 4H), 1.27 (s, 9H), 1.21 (s, 9H).
Example 57
Figure imgf000068_0001
(S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-(4,4,4-trifluorobutoxy)-
[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added 4,4,4-trifluorobutyl methanesulfonate (24.96 mg, 0.121 mmol) and K2CO3 (25.09 mg, 0.182 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-(4,4,4- trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate (42 mg, 0.026 mmol, 42.4 % yield) as brown oil. LCMS (M + H) = 606.4; Retention time (10 mM NH4HCO3) = 2.712 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate(42 mg, 0.069 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.32 mg, 0.208 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert- butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'- bipyridin]-5'-yl)acetic acid (17.8 mg, 0.032 mmol, 45.5 % yield) as white solid. LCMS (M + H) = 564.2; Retention time (10 mM NH4HCO3) = 1.664 min. 1HNMR (400 MHz, MeOD) d 8.40 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.58 (dd, J = 8.6, 2.9 Hz, 1H), 7.47 (d, J = 8.6 Hz, 1H), 5.85 (s, 1H), 4.24 (t, J = 6.0 Hz, 2H), 3.30- 2.66 (m, 7H), 2.50- 2.36 (m, 2H), 2.16- 2.09 (m, 2H), 1.66- 1.28 (m, 12H), 1.21 (s, 9H).
Example 58
Figure imgf000069_0001
(S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-((tetrahydro-2H-pyran-4- yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (25.09 mg, 0.182 mmol) and (tetrahydro-2H-pyran-4-yl)methyl methanesulfonate (23.51 mg, 0.121 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]-5'- yl)acetate (32 mg, 0.015 mmol, 24.05 % yield) as yellow oil. LCMS (M + H) = 594.2; Retention time (10 mM NH4HCO3) = 2.611 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]-5'- yl)acetate (32 mg, 0.054 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.47 mg, 0.162 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NLLHCCb); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5- ((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (6.3 mg, 0.011 mmol, 21.19 % yield) as white solid. LCMS (M + H) = 552.2; Retention time (10 mM NH4HCO3) = 1.522 min. 1HNMR (400 MHz, MeOD) d 8.37 (d, J = 2.8 Hz, 1H), 8.15 (s, 1H), 7.57 (dd, J = 8.6, 2.9 Hz, 1H), 7.46 (d, J = 8.6 Hz, 1H), 5.85 (s, 1H), 4.04- 4.00 (m, 4H), 3.51 (t, J = 11.0 Hz, 2H), 3.30- 2.66 (m, 7H), 2.17-2.16 (m, 1H), 1.83 (d, J = 12.4 Hz, 2H), 1.67- 1.28 (m, 14H), 1.21 (s, 9H).
Example 59
Figure imgf000070_0001
(2S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-((tetrahydrofuran-3- yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4- methylpiperidin-l-yl)-5-hydroxy-6'-methyl-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.062 mmol) in DMF (10 mL) was added K2CO3 (25.7 mg, 0.186 mmol) and (tetrahydrofuran-3- yl)methyl methanesulfonate (22.36 mg, 0.124 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl
acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(4'-(4- ethyl-4-methylpiperidin-l-yl)-6'-methyl-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'- bipyridin]-5'-yl)acetate (35 mg, 0.019 mmol, 31.0 % yield) as a yellow oil. LCMS (M + H) = 568.2; Retention time (10 mM NH4HCO3) = 2.451 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetate (31 mg, 0.053 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (6.42 mg, 0.160 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product._The crude product was purified by Prep- HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (2S)-2- (tert-butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-((tetrahydrofuran-3- yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (11.8 mg, 0.022 mmol, 41.0 % yield) as white solid. LCMS (M + H) = 538.2; Retention time (10 mM NH4HCO3) = 1.487 min. 1HNMR (400 MHz, MeOD) d 8.38 (d, J = 2.8 Hz, 1H), 8.15 (s, 1H), 7.58 (dd, J = 8.6, 2.9 Hz, 1H), 7.46 (d, J = 8.6 Hz, 1H), 5.85 (s, 2H), 4.23- 4.05 (m, 2H), 3.95 (dt, J = 14.5, 7.4 Hz, 2H), 3.84- 3.71 (m, 2H), 3.30- 2.66 (m, 7H), 2.26 -2.13 (m, 1H), 1.88- 1.80 (m, 1H), 1.68 -1.28 (m, 13H), 1.21 (s, 9H).
Example 60
Figure imgf000071_0001
(S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-(2-(tetrahydro-2H-pyran-
4-yl)ethoxy)-[2,3'-bipyridin]-5'-yl)acetic acid Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (45 mg, 0.091 mmol) in DMF (10 mL) was added K2CO3 (37.6 mg, 0.272 mmol) and 2-(tetrahydro-2H-pyran-4-yl)ethyl methanesulfonate (28.4 mg, 0.136 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]-5'- yl)acetate (52 mg, 0.018 mmol, 20.09 % yield) as yellow oil. LCMS (M + H) = 608.5; Retention time (10 mM NH4HCO3) = 2.338 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]-5'- yl)acetate (52 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NLLHCCh); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert-butoxy)-2-(6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-5-(2- (tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (17.0 mg, 0.028 mmol, 32.5 % yield) as white solid. LCMS (M + H) = 566.1; Retention time (10 mM NH4HCO3) = 1.562 min. ¾ NMR (400 MHz, MeOD) d 8.37 (d, J = 2.7 Hz, 1H), 8.16 (s, 1H), 7.56 (dd, J = 8.6, 2.9 Hz, 1H), 7.46 (d, J = 8.6 Hz, 1H), 5.86 (s, 1H), 4.23 (t, J = 6.2 Hz, 2H), 3.97 (dd, J = 11.0, 3.4 Hz, 2H), 3.47 (td, J = 11.9, 2.1 Hz, 2H), 3.30 - 2.66 (m, 7H), 1.93 - 1.29 (m, 19H), 1.21 (s, 9H).
Example 61
Figure imgf000073_0001
(S)-2-(tert-Butoxy)-2-(5-(2-(cyclopentyloxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8- yl)-[2,3'-bipyridin]-5'-yl)acetic acid Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'-
(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (16.73 mg, 0.121 mmol) and 2-(cyclopentyloxy)ethyl
methanesulfonate (18.91 mg, 0.091 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl isopropyl (S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'- yl)acetate (28 mg, 0.042 mmol, 69.8 % yield) as yellow oil. LCMS (M + H) = 608.4;
Retention time (10 mM NH4HCO3) = 2.400 min.
Step 2: To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'- yl)acetate (28 mg, 0.046 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (5.53 mg, 0.138 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NLLHCCh); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert-butoxy)-2-(5-(2-(cyclopentyloxy)ethoxy)-6'-methyl-4'-(8- azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (8.4 mg, 0.015 mmol, 32.2 % yield) as white solid. LCMS (M + H) = 566.1; Retention time (10 mM NH4HCO3) = 1.676 min. 1HNMR (400 MHz, MeOD) d 8.40 (d, J = 2.7 Hz, 1H), 8.16 (s, 1H), 7.59 (dd, J = 8.6, 2.9 Hz, 1H), 7.46 (d, J = 8.6 Hz, 1H), 5.85 (s, 1H), 4.32- 4.24 (m, 2H), 4.10- 4.01 (m, 1H), 3.87- 3.80 (m, 2H), 3.30- 2.66 (m, 7H), 1.85-1.28 (m, 20H), 1.21 (s, 9H).
Example 62
Figure imgf000074_0001
(S)-2-(tert-Butoxy)-2-(5-(2,2-difluorobutoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-
[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (30 mg, 0.061 mmol) in DMF (10 mL) was added K2CO3 (25.09 mg, 0.182 mmol) and l-bromobutan-2-one (18.28 mg, 0.121 mmol). The mixture was stirred for 20 hours at 45 °C, cooled and diluted with water. The mixture was extracted with ethyl acetate (30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-5-(2-oxobutoxy)-4'-(8-azaspiro[4.5]decan-8-yl)- [2,3'-bipyridin]-5'-yl)acetate (16 mg, 0.028 mmol, 46.7 % yield) as yellow oil. LCMS (M + H) = 566.5; Retention time (0.0l%TFA) = 2.202 min.
Step 2: A mixture of isopropyl (S)-2-(tert-butoxy)-2-(6'-methyl-5-(2-oxobutoxy)- 4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate (16 mg, 0.028 mmol) and DAST (5 mL) was stirred for 20 hours at 20 °C. The mixture was diluted with water and ethyl acetate (30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ethyl acetate/petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan- 8-yl)-[2,3'-bipyridin]-5'-yl)acetate (9 mg, 0.015 mmol, 54.1 % yield) as yellow oil. LCMS (M + H) = 587.3; Retention time (0.0l%TFA) = 2.218 min.
Step 3 : To a solution of isopropyl (S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-6'- methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetate ( 40mg, 0.068 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (8.17 mg, 0.204 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml), extracted with ethyl acetate (5 ml) and organic layer was concentrated to give crude product. The crude product was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: water (10 mM NH4HCO3); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give the desired product (S)-2-(tert-butoxy)-2-(5-(2,2- difluorobutoxy)-6'-methyl-4'-(8-azaspiro[4.5]decan-8-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (16.7 mg, 0.030 mmol, 43.9 % yield) as white solid. LCMS (M + H) = 546.2; Retention time (10 mM NH4HCO3) = 1.662 min. 1HNMR (400 MHz, MeOD) d 8.45 (d, J = 2.8 Hz, 1H), 8.17 (s, 1H), 7.65 (dd, J = 8.6, 3.0 Hz, 1H), 7.50 (d, J = 8.6 Hz, 1H), 5.86 (s, 1H), 4.42 (t, J = 12.0 Hz, 2H), 3.30- 2.66 (m, 7H), 2.14-2.13 (m, 2H), 1.70- 1.29 (m, 12H), 1.21 (s, 9H), 1.12-1.11 (m, 3H).
Example 63 and 64
Figure imgf000075_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(5-(2-(cyclopentyloxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-
2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(cyclopentyloxy)ethyl methanesulfonate (42.0 mg, 0.202 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(cyclopentyloxy)ethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.067 mmol, 66.0 % yield) as yellow oil. LCMS (M + H) = 608.3; Retention time (10 mM NH4HC03) = 2.902 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetate (52 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (34.6 mg, 0.061 mmol, 71.5 % yield) as white solid. LCMS (M + H) = 566.2; Retention time (10 mM NH4HC03) = 1.661 min.
Step 3 : The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2- (cyclopentyloxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (34.6 mg, 0.061 mmol) were separated by SFC [Column AD-H 4.6 x 100 mm 5 pm; Co- Solvent EtOH(l% ammonia/methanol)] to obtain
First eluting diastereomer 63: (8.6 mg, 0.015 mmol, 24.56 % yield). LCMS (M + H) = 566.2 ; Retention time (10 mM NH4HC03) = 1.673 min. 1HNMR (400 MHz, MeOD) d 8.28 (d, J = 2.8 Hz, 1H), 8.01 (s, 1H), 7.48 (dd, J = 8.6, 2.9 Hz, 1H), 7.34 (d, J = 8.6 Hz, 1H), 5.70 (s, 1H), 4.16 (dd, J = 5.3, 3.7 Hz, 2H), 3.94 (ddd, J = 10.0, 6.4, 3.4 Hz, 1H), 3.71 (dd, J = 5.3, 3.7 Hz, 2H), 3.08-1.98 (m, 7H), 1.72- 1.13 (m, 20H), 1.08 (s, 9H) and
Second eluting diastereomer 64: (7.2 mg, 0.012 mmol, 20.01 % yield). LCMS (M + H) = 566.2; Retention time (10 mM NH4HC03) = 1.661 min. 1HNMR (400 MHz, MeOD) d 8.28 (t, J = 4.6 Hz, 1H), 8.03 (s, 1H), 7.48 (dd, J = 8.6, 2.9 Hz, 1H), 7.34 (dd, J = 14.3, 7.6 Hz, 1H), 5.86 (s, 1H), 4.16 (dd, J = 5.3, 3.7 Hz, 2H), 3.93 (ddd, J = 9.8, 6.4, 3.4 Hz, 1H), 3.74- 3.67 (m, 2H), 3.04- 2.42 (m, 5H), 1.95- 1.13 (m, 22H), 1.09 (s, 9H).
Example 65 and 66
Figure imgf000077_0001
First eluting isomer Second eluting isomer
2S)-2-(tert-Butoxy)-2-(5-(cyclopropylmethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)- yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and (bromomethyl)cyclopropane (27.2 mg, 0.202 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (53 mg, 0.084 mmol, 84 % yield) as yellow oil. LCMS (M + H) = 550.2; Retention time (10 mM NH4HC03) = 2.705 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)- 6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.095 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (7.57 mg, 0.189 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (34.9 mg,
0.069 mmol, 72.7 % yield) as white solid. LCMS (M + H) = 508.2; Retention time (10 mM NH4HC03) = 1.592 min.
Step 3 : The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(cyclopropylmethoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (32.1 mg, 0.063 mmol) were separated by SFC [Column AD-H 4.6 x 100 mm; 5 pm; Co-Solvent EtOH (l%ammonia/methanol)] to obtain
First eluting diastereomer 65: (9.6 mg, 0.019 mmol, 29.9 % yield). LCMS (M + H) = 508.2; Retention time (10 mM NH4HC03) = 1.605 min. 1HNMR (400 MHz, MeOD) d 8.35 (d, J = 2.8 Hz, 1H), 8.11 (s, 1H), 7.54 (dd, J = 8.6, 2.9 Hz, 1H), 7.45 (d, J = 8.6 Hz, 1H), 5.80 (s, 1H), 4.00 (d, J = 7.0 Hz, 2H), 2.66 (s, 3H), 2.31- 1.25 (m, 17H), 1.18 (s, 9H), 0.74- 0.65 (m, 2H), 0.50- 0.34 (m, 2H) and
Second eluting diastereomer 66: (6.3 mg, 0.012 mmol, 19.63 % yield) . LCMS (M + H) = 508.0; Retention time (10 mM NH4HC03) = 1.595 min. 1H NMR (400 MHz, MeOD) d 8.23 (d, J = 2.7 Hz, 1H), 7.98 (s, 1H), 7.42 (dd, J = 8.6, 2.8 Hz, 1H), 7.33 (d, J = 8.6 Hz, 1H), 5.78 (s, 1H), 3.94 - 3.84 (m, 2H), 2.52 (s, 3H), 2.18 -1.12 (m, 17H), 1.07 (s, 9H), 0.62- 0.52 (m, 2H), 0.31 (q, J = 4.6 Hz, 2H).
Example 67 and 68
Figure imgf000078_0001
First eluting isomer Second eluting isomer
(S)-2-(tert-Butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-5-(2-(2S)-2-(tert-butoxy)-2-(5-
(2-isopropoxyethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in DMF (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(2-bromoethoxy)propane (33.7 mg, 0.202 mmol. The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-isopropoxyethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (53 mg, 0.091 mmol, 90 % yield) as yellow oil. LCMS (M + H) = 582.2; Retention time (10 mM NH4HC03) = 2.662 min.
Step 2
To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-isopropoxyethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (53 mg, 0.091 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.93 mg, 0.273 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (S)-2-(tert-butoxy)-2-(4'-(4-ethyl-4-methylpiperidin-l-yl)-5-(2- (2S)-2-(tert-butoxy)-2-(5-(2-isopropoxyethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)- yl)-[2,3'-bipyridin]-5'-yl)acetic acid (32.7 mg, 0.061 mmol, 66.5 % yield) as white solid. LCMS (M + H) = 540.2; Retention time (10 mM NH4HC03) = 1.568 min.
Step 3
The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2-isopropoxyethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (32.7 mg, 0.061 mmol) were separated by SFC [Column AD-H 4.6 x 100 mmmm 5 pm; Co-Solvent EtOH (1% ammonia/methanol Ammonia)] to obtain.
First eluting diastereomer 67: (9.2 mg, 0.017 mmol, 28.1 % yield). LCMS (M + H) =
540.2; Retention time (10 mM NH4HC03) = 1.568 min. 1HNMR (400 MHz, MeOD) d 8.40 (d, J = 2.8 Hz, 1H), 8.14 (s, 1H), 7.60 (dd, J = 8.6, 2.9 Hz, 1H), 7.47 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.28 (dd, J = 5.3, 3.8 Hz, 2H), 3.87 (dd, J = 5.4, 3.7 Hz, 2H), 3.74 (dq, J = 12.2, 6.1 Hz, 1H), 3.17- 2.40 (m, 5H), 1.90 -1.27 (m, 14H), 1.26- 1.16 (m, 15H) and Second eluting diastereomer 68: (8.9 mg, 0.016 mmol, 26.2 % yield) . LCMS (M + H) = 540.2; Retention time (10 mM NH4HC03) = 1.580 min. 1HNMR (400 MHz, MeOD) d 8.29 (d, J = 2.8 Hz, 1H), 8.03 (s, 1H), 7.48 (dd, J = 8.6, 2.9 Hz, 1H), 7.40- 7.30 (m, 1H), 5.74-5.73(m, 2H), 4.19- 4.12 (m, 2H), 3.75 (dd, J = 5.3, 3.8 Hz, 2H), 3.63 (dp, J = 12.3, 6.1 Hz, 1H), 3.07- 2.39 (m, 6H), 1.97-1.15 (m, 13H), 1.13- 1.09 (m, 15H). Example 69
Figure imgf000080_0001
(2S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-((tetrahydrofuran- 3-yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and (tetrahydrofuran-3-yl)methyl methanesulfonate (36.4 mg, 0.202 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5- ((tetrahydrofuran-3-yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetate (53 mg, 0.086 mmol, 86 % yield) as yellow oil. LCMS (M + H) = 580.2; Retention time (10 mM NH4HC03) = 2.474 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'-bipyridin]-5'- yl)acetate (53 mg, 0.091 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.97 mg, 0.274 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-((tetrahydrofuran-3-yl)methoxy)-[2,3'- bipyridin]-5'-yl)acetic acid (27.3 mg, 0.050 mmol, 54.2 % yield) as white solid. LCMS (M + H) = 538.2; Retention time (10 mM NH4HC03) = 1.500 min. 1HNMR (400 MHz, MeOD) d 8.43- 8.35 (m, 1H), 8.15 (d, J = 10.1 Hz, 1H), 7.59 (dt, J = 8.6, 2.8 Hz, 1H), 7.52- 7.41 (m, 1H), 5.82 (s, 1H), 4.12 (ddd, J = 19.9, 13.1, 7.8 Hz, 2H), 3.94 (qd, J = 7.4, 2.2 Hz, 2H), 3.86 -3.71 (m, 2H), 3.28- 2.57 (m, 8H), 2.26- 1.26 (m, 14H), 1.20 (s, 9H).
Example 70
Figure imgf000081_0001
(2S)-2-(tert-Butoxy)-2-(5-(2-(tert-butoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin- 2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) , was added 2-(tert-butoxy)ethyl methanesulfonate (39.6 mg, 0.202 mmol) and K2CO3 (41.8 mg, 0.303 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(tert-butoxy)ethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.081 mmol, 80 % yield)as brown oil. LCMS (M + H) = 596.3; Retention time (10 mM NH4HC03) = 2.786 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(tert- butoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(5-(2- (tert-butoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (29 mg, 0.051 mmol, 59.8 % yield) as white solid. LCMS (M + H) = 554.2; Retention time (10 mM NH4HC03) = 1.631 min. 1HNMR (400 MHz, MeOD) d 8.40 (t, J = 3.3 Hz, 1H), 8.14 (d, J = 5.0 Hz, 1H), 7.60 (dd, J = 8.6, 2.8 Hz, 1H), 7.47 (dd, J = 8.6, 5.6 Hz, 1H), 5.81 (s, 1H), 4.31- 4.21 (m, 2H), 3.87 -3.75 (m, 2H), 3.18- 2.58 (m, 5H), 2.14- 1.10 (m, 32H).
Example 71 and 72
Figure imgf000082_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-(2-(tetrahydro-2H- pyran-4-yl)ethoxy)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and 2-(tetrahydro-2H-pyran-4-yl)ethyl methanesulfonate (31.5 mg, 0.151 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5- (2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.082 mmol,
81 % yield) as yellow oil. LCMS (M + H) = 608.2; Retention time (10 mM NH4HC03) = 2.649 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]- 5'-yl)acetate (52 mg, 0.086 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.27 mg, 0.257 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC {Instrument Gilson 281 (PHG-009); Column Xtimate Prep Cl 8 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40- 68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert- butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-(2-(tetrahydro-2H-pyran-4- yl)ethoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (21.5 mg, 0.038 mmol, 44.4 % yield) as white solid. LCMS (M + H) = 566.2; Retention time (10 mM NH4HC03) = 1.560 min.
Step 3 : The diastereomers of (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(2-(tetrahydro-2H-pyran-4-yl)ethoxy)-[2,3'-bipyridin]- 5'-yl)acetic acid (21.5 mg, 0.038 mmol) were separated by SFC [Column IC (4.6 x 100 mm; 5 pm); Co-Solvent MeOH (0.2%ammonia/methano)] to obtain
First eluting diastereomer 71: (4.5 mg, 7.70 pmol, 20.27 % yield). LCMS (M + H) = 566.1; Retention time (10 mM NH4HC03) = 1.558 min. ¾NMR (400 MHz, MeOD) d 8.37 (d, J = 2.8 Hz, 1H), 8.13 (s, 1H), 7.57 (dd, J = 8.6, 2.9 Hz, 1H), 7.46 (d, J = 8.6 Hz, 1H), 5.82 (s, 1H), 4.23 (t, J = 6.2 Hz, 2H), 3.97 (dd, J = 11.1, 3.4 Hz, 2H), 3.47 (td, J = 11.9, 1.9 Hz,
2H), 2.66 (s, 3H), 1.93- 1.29 (m, 23H), 1.20 (s, 9H) and
Second eluting diastereomer 72: (3.7 mg, 6.54 pmol, 17.21 % yield). LCMS (M + H) = 566.2 ; Retention time (10 mM NH4HC03) = 1.545 min. 1HNMR (400 MHz, MeOD) d 8.26 (d, J = 2.7 Hz, 1H), 8.03 (s, 1H), 7.45 (dd, J = 8.6, 2.9 Hz, 1H), 7.36 (d, J = 8.6 Hz, 1H), 5.83 (s, 1H), 4.11 (t, J = 6.1 Hz, 2H), 3.85 (dd, J = 10.9, 3.7 Hz, 2H), 3.34 (td, J =
11.9, 2.0 Hz, 2H), 2.52 (s, 3H), 2.13- 2.07 (m, 1H), 1.98- 1.16 (m, 23H), 1.08 (s, 9H).
Example 73 and 74
Figure imgf000083_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(5-(2-(2-chlorophenoxy)ethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-(2-chlorophenoxy)ethyl
methanesulfonate (76 mg, 0.303 mmol. The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(2-chlorophenoxy)ethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.065 mmol, 64.7 % yield) as yellow oil. LCMS (M + H) = 650.1; Retention time (10 mM NH4HC03) = 2.742 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetate (50 mg, 0.077 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.23 mg, 0.231 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (36.5 mg, 0.060 mmol, 78 % yield) as white solid. LCMS (M + H) = 608.1; Retention time (10 mM NH4HC03) = 1.687 min.
Step 3 : The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2-(2- chlorophenoxy)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (36.5 mg, 0.060 mmol) were separated by SFC [Column IC (4.6 x 100 mm; 5 um); Co-Solvent MeOH (0.2%ammonia/methanol)].
First eluting diastereomer 73: (3.9 mg, 6.41 pmol, 10.68 % yield). LCMS (M + H) = 608.1; Retention time (10 mM NH4HC03) = 1.662 min. lHNMR (400 MHz, MeOD) d 8.47 (d, J = 2.8 Hz, 1H), 8.16 (d, J = 9.3 Hz, 1H), 7.70 (dd, J = 8.6, 2.9 Hz, 1H), 7.50 (d, J = 8.6 Hz, 1H), 7.38 (dd, J = 7.9, 1.6 Hz, 1H), 7.34 - 7.25 (m, 1H), 7.17 (dd, J = 8.3, 1.3 Hz, 1H),
6.97 (td, J = 7.7, 1.4 Hz, 1H), 5.96 (s, 1H), 4.62- 4.55 (m, 2H), 4.50- 4.44 (m, 2H), 2.66 (s, 3H), 2.24-2.17 (m, 1H), 2.10- 1.99 (m, 1H), 1.91-1.29 (m, 14H), 1.21 (s, 9H) and
Second eluting diastereomr 74: (4.1 mg, 6.74 pmol, 11.23 % yield). LCMS (M + H) = 608.1; Retention time (10 mM NH4HC03) = 1.669 min. ¾ NMR (400 MHz, MeOD) d 8.33 (d, J = 2.8 Hz, 1H), 8.01 (s, 1H), 7.56 (dd, J = 8.6, 2.9 Hz, 1H), 7.35 (d, J = 8.6 Hz, 1H), 7.26 (dd, J = 7.9, 1.6 Hz, 1H), 7.20- 7.14 (m, 1H), 7.05 (dd, J = 8.3, 1.3 Hz, 1H), 6.85 (td, J = 7.7, 1.4 Hz, 1H), 5.67 (s, 1H), 4.46 (dd, J = 5.4, 3.1 Hz, 2H), 4.35 (dd, J = 5.4, 3.1 Hz, 2H), 2.57 (s, 3H), 2.00- 1.87 (m, 1H), 1.72- 1.14 (m, 15H), 1.07 (s, 9H).
Example 75
Figure imgf000085_0001
(2S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-((tetrahydro-2H- pyran-4-yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and (tetrahydro-2H-pyran-4-yl)methyl methanesulfonate (29.4 mg, 0.151 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5- ((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]-5'-yl)acetate (53 mg, 0.085 mmol,
84 % yield) as yellow oil. LCMS (M + H) = 594.2; Retention time (10 mM NH4HC03) = 2.565 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'-bipyridin]- 5'-yl)acetate (53 mg, 0.089 mmol) in methanol (10 mL) and water (2 mL) was added NaOH (10.71 mg, 0.268 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-((tetrahydro-2H-pyran-4-yl)methoxy)-[2,3'- bipyridin]-5'-yl)acetic acid (3.9 mg, 6.84 pmol, 7.66 % yield) as white solid. LCMS (M + H) = 552.2 ; Retention time (10 mM NH4HC03) = 1.522 min. 1HNMR (400 MHz, MeOD) 5 8.40 - 8.34 (m, 1H), 8.13 (d, J = 9.5 Hz, 1H), 7.62 - 7.53 (m, 1H), 7.50 - 7.42 (m, 1H), 5.96 (s, 1H), 4.09- 3.97 (m, 4H), 3.51 (t, J = 11.7 Hz, 2H), 3.18- 2.58 (m, 5H), 2.23-1.26 (m, 19H), 1.20 (s, 9H).
Example 76 and 77
Figure imgf000086_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(5-butoxy-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'- bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and l-bromobutane (27.6 mg, 0.202 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2- (tert-butoxy)-2-(5-butoxy-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetate (52 mg, 0.026 mmol, 25.6 % yield) as yellow oil. LCMS (M + H) = 552.4;
Retention time (10 mM NH4HC03) = 1.787 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-butoxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (52 mg, 0.094 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (3.77 mg, 0.094 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC {Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(5-butoxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (28.8 mg, 0.057 mmol, 60.0 % yield) as white solid. LCMS (M + H) = 510.1; Retention time (10 mM NH4HC03) = 1.687 min.
Step 3 : The diastereomers of (2S)-2-(tert-butoxy)-2-(5-butoxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (28.8 mg, 0.057 mmol) were separated by SFC [Column AD-H (4.6 x 100 mm; 5 pm); Co-Solvent EtOH(l .0% ammonia/methanol)] to obtain
First eluting diastereomer 76: (4.3 mg, 8.05 pmol, 14.24 % yield). LCMS (M + H) = 510.1; Retention time (10 mM NH4HC03) = 1.663 min. lHNMR (400 MHz, MeOD) d 8.23 (d, J = 2.8 Hz, 1H), 8.02 (d, J = 9.4 Hz, 1H), 7.43 (dd, J = 8.6, 2.9 Hz, 1H), 7.34 (d, J = 8.6 Hz, 1H), 5.69 (s, 1H), 4.04 (t, J = 6.4 Hz, 2H), 2.53 (d, J = 9.1 Hz, 3H), 1.78- 1.15 (m, 20H), 1.08 (s, 9H), 0.92 (t, J = 7.4 Hz, 3H) and
Second eluting diastereomer 77: (2.7 mg, 4.87 pmol, 8.62 % yield). LCMS (M + H) = 510.1; Retention time (10 mM NH4HC03) = 1.657 min. ¾ NMR (400 MHz, MeOD) d 8.37 (d, J = 2.7 Hz, 1H), 8.16 (s, 1H), 7.56 (dd, J = 8.6, 2.8 Hz, 1H), 7.47 (d, J = 8.6 Hz, 1H), 5.97 (s, 1H), 4.17 (t, J = 6.4 Hz, 2H), 2.64 (s, 3H), 2.42 - 1.23 (m, 20H), 1.21 (s, 9H), 1.03 (t, J = 7.4 Hz, 3H).
Example 78 and 79
Figure imgf000087_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-(4,4,4- trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetic acid Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) , was added K2CO3 (41.8 mg, 0.303 mmol) and 4,4,4-trifluorobutyl methanesulfonate (41.6 mg, 0.202 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-(4,4,4- trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.080 mmol, 80 % yield) as brown oil. LCMS (M + H) = 606.2; Retention time (10 mM NH4HC03) = 2.688 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetate (51 mg, 0.084 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.10 mg, 0.253 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'- yl)acetic acid (32.5 mg, 0.058 mmol, 68.5 % yield) as white solid. LCMS (M + H) = 564.1; Retention time (10 mM NH4HC03) = 1.651 min.
Step 3 : The diastereomers of (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(4,4,4-trifluorobutoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (32.5 mg, 0.058 mmol) were separated by SFC (Column IC (4.6 x 100 mm; 5 pm); Co- Solvent MeOH (0.2%ammonia/methanol)] to obtain
First eluting diastereomer 78: (4.8 mg, 8.38 pmol, 14.53 % yield). LCMS (M + H) = 564.2; Retention time (10 mM NH4HC03) = 1.629 min. 1HNMR (400 MHz, MeOD) d 8.38 (d, J = 2.8 Hz, 1H), 8.07 (s, 1H), 7.57 (dd, J = 8.6, 2.8 Hz, 1H), 7.47 (d, J = 8.6 Hz, 1H), 5.87 (s, 1H), 4.23 (t, J = 6.0 Hz, 2H), 3.28- 2.88 (m, 2H), 2.64 (s, 3H), 2.50- 2.36 (m, 2H), 2.15- 2.04 (m, 2H), 1.89- 1.24 (m, 14H), 1.18 (s, 9H) and
Second eluting diastereomer 79: (4.4 mg, 7.70 pmol, 13.35 % yield). LCMS (M + H) = 564.2; Retention time (10 mM NH4HC03) = 1.640 min. 1HNMR (400 MHz, MeOD) d 8.36 (d, J = 2.8 Hz, 1H), 8.06 (s, 1H), 7.57 (dd, J = 8.6, 2.9 Hz, 1H), 7.45 (d, J = 8.5 Hz, 1H), 5.75 (s, 1H), 4.23 (t, J = 6.1 Hz, 2H), 3.29 - 3.00 (m, 2H), 2.65 (s, 3H), 2.53- 2.35 (m, 2H), 2.15- 2.04 (m, 2H), 1.82 -1.23 (m, 14H), 1.17 (s, 9H).
Example 80 and 81
Figure imgf000089_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(5-(cyclobutylmethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)- yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (41.8 mg, 0.303 mmol) and (bromomethyl)cyclobutane (30.1 mg, 0.202 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel
chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.079 mmol, 79 % yield) as yellow oil. LCMS (M + H) = 564.4; Retention time (0.01% TFA) = 1.800 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)- 6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.089 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (10.64 mg, 0.266 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (29.5 mg,
0.057 mmol, 63.8 % yield) as white solid. LCMS (M + H) = 522.2; Retention time (10 mM NH4HC03) = 1.705 min.
Step 3 : The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(cyclobutylmethoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (29.5 mg,
0.057 mmol) were separated by SFC [Column AD-H (4.6 x 100 mm; 5 pm); Co-Solvent EtOH (1.0% ammonia/methanol)] to obtain
First eluting diastereomer 80: (4.3 mg, 8.13 pmol, 14.37 % yield). LCMS (M + H) = 522.2; Retention time (10 mM NH4HC03) = 1.685 min. 1HNMR (400 MHz, MeOD) d 8.24 (d, J = 2.8 Hz, 1H), 8.01 (s, 1H), 7.44 (dd, J = 8.6, 2.9 Hz, 1H), 7.33 (d, J = 8.5 Hz, 1H), 5.69 (s, 1H), 4.00 (d, J = 6.5 Hz, 2H), 3.11- 2.46 (m, 5H), 2.22- 1.12 (m, 21H), 1.08 (s, 9H) and Second eluting diastereomer 81: (4.4 mg, 8.43 pmol, 14.92 % yield). LCMS (M + H) = 522.2; Retention time (10 mM NH4HC03) = 1.686 min. ¾ NMR (400 MHz, MeOD) d 8.37 (d, J = 2.8 Hz, 1H), 8.16 (s, 1H), 7.56 (dd, J = 8.6, 2.9 Hz, 1H), 7.47 (d, J = 8.6 Hz, 1H), 5.97 (s, 1H), 4.13 (d, J = 6.6 Hz, 2H), 3.24- 2.60 (m, 5H), 2.26- 1.25 (m, 21H), 1.21 (s, 9H).
Example 82 and 83
Figure imgf000090_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(5-(2,2-difluorobutoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)- yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (80 mg, 0.161 mmol) in DMF (10 mL) was added K2CO3 (66.9 mg, 0.484 mmol) and l-bromobutan-2-one (48.7 mg, 0.323 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford 5'- ((S)-l-(tert-butoxy)-2-isopropoxy-2-oxoethyl)-6'-methyl-4'-(octahydroisoquinolin-2(lH)- yl)-[2,3'-bipyridin]-5-yl butyrate (72 mg, 0.050 mmol, 31.0 % yield) as yellow oil. LCMS (M + H) = 566.3; Retention time (0.0l%TFA) = 2.028 min.
Step 2: A solution of 5'-((S)-l-(tert-butoxy)-2-isopropoxy-2-oxoethyl)-6'-methyl- 4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5-yl butyrate (72 mg, 0.127 mmol) in DAST (5 mL) was stirred for 20 hours at 20 °C. The mixture was diluted with ethyl acetate ( 30 mL), washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10:1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(5-(l,l- difluorobutoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (60 mg, 0.096 mmol, 76 % yield). LCMS (M + H) = 588.3; Retention time (0.0l%TFA) = 2.178 min.
Step 3 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)- 6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate ( 60mg, 0.102 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (12.25 mg, 0.306 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (47.8 mg,
0.088 mmol, 86 % yield) as white solid. LCMS (M + H) = 546.2 ; Retention time (10 mM NH4HC03) = 1.621 min.
Step 4: The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2,2-difluorobutoxy)-6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid (47.8 mg,
0.088 mmol) were separated by SFC [Column IC (4.6 x 100 mm; 5 pm); Co-Solvent MeOH (0.2% ammonia/methanol)] to obtain
First eluting diastereomer 82: (4.8 mg, 8.05 pmol, 9.19 % yield). LCMS (M + H) = 546.2 ; Retention time (10 mM NH4HC03) = 1.604 min. 1HNMR (400 MHz, MeOD) d 8.46 (d, J = 2.8 Hz, 1H), 8.16 (s, 1H), 7.66 (dd, J = 8.6, 3.0 Hz, 1H), 7.52 (d, J = 8.6 Hz, 1H), 5.98 (s, 1H), 4.42 (t, J = 12.0 Hz, 2H), 3.28 - 2.83 (m, 2H), 2.65 (s, 3H), 2.21- 2.06 (m, 2H), 1.90- 1.27 (m, 14H), 1.20 (s, 9H), 1.12 (t, J = 7.5 Hz, 3H) and Second eluting diastereomer 83: (4.9 mg, 8.33 mihoΐ, 9.51 % yield). LCMS (M + H) = 546.2 ; Retention time (10 mM NH4HC03) = 1.614 min. 1HNMR (400 MHz, MeOD) d 8.45 (d, J = 2.8 Hz, 1H), 8.14 (s, 1H), 7.65 (dd, J = 8.6, 3.0 Hz, 1H), 7.50 (d, J = 8.6 Hz, 1H), 5.83 (s, 1H), 4.41 (t, J = 12.0 Hz, 2H), 3.20 - 2.81 (m, 2H), 2.65 (s, 3H), 2.24- 2.02 (m, 2H), 1.80- l.32(m, 14H), 1.20 (s, 9H), 1.12 (t, J = 7.5 Hz, 3H).
Example 84 and 85
Figure imgf000092_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-(2- phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-phenoxyethyl methanesulfonate (65.4 mg, 0.303 mmol) . The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-(2- phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.049 mmol, 49.0 % yield) as yellow oil. LCMS (M + H) = 616.2; Retention time (10 mM NH4HC03) = 2.679 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.081 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.74 mg, 0.244 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(6'- methyl-4'-(octahydroisoquinolin-2(lH)-yl)-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'- yl)acetic acid (28.5 mg, 0.050 mmol, 61.2 % yield) as white solid and mixture of diastereomers. LCMS (M + H) = 574.2; Retention time (10 mM NH4HC03) = 1.634 min.
Step 3 : The diastereomers of (2S)-2-(tert-Butoxy)-2-(6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-5-(2-phenoxyethoxy)-[2,3'-bipyridin]-5'-yl)acetic acid (28.5 mg, 0.050 mmol) were separated by SFC [Column AD-H 4.6 x 100 mm mm 5 um; Co-Solvent EtOH (l%ammonia/methanol)].
First eluting diastereomer 84: (4.6 mg, 7.69 pmol, 15.48 % yield). LCMS (M + H) = 574.1; Retention time (10 mM NH4HC03) = 1.638 min. 1HNMR (400 MHz, MeOD) d 8.44 (d, J = 2.8 Hz, 1H), 8.15 (s, 1H), 7.65 (dd, J = 8.6, 2.9 Hz, 1H), 7.49 (d, J = 8.6 Hz, 1H), 7.35- 7.26 (m, 2H), 6.98 (dd, J = 14.2, 7.6 Hz, 3H), 5.82 (s, 1H), 4.52 (dd, J = 5.4, 3.3 Hz, 2H), 4.41 (dd, J = 5.4, 3.3 Hz, 2H), 2.67 (s, 3H), 2.29- 1.28 (m, 16H), 1.22 (s, 9H) and
Second eluting diastereomer 85: (4.7 mg, 8.19 pmol, 16.49 % yield). LCMS (M + H) = 574.2; Retention time (10 mM NH4HC03) = 1.630 min. 1HNMR (400 MHz, MeOD) d 8.45 (d, J = 2.9 Hz, 1H), 8.17 (s, 1H), 7.65 (dd, J = 8.5, 2.9 Hz, 1H), 7.50 (d, J = 8.5 Hz, 1H), 7.35- 7.24 (m, 2H), 7.03- 6.91 (m, 3H), 4.53 (dd, J = 5.9, 2.8 Hz, 2H), 4.41 (dd, J = 5.3, 3.4 Hz, 2H), 2.64 (s, 3H), 2.25- 1.27 (m, 16H), 1.21 (s, 9H).
Example 86 and 87
Figure imgf000093_0001
First eluting isomer Second eluting isomer
(2S)-2-(tert-Butoxy)-2-(5-(2-(l,3-dimethyl-lH-pyrazol-4-yl)ethoxy)-6'-methyl-4'- (octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetic acid
Step 1 : To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-hydroxy-6'-methyl-4'-
(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.101 mmol) in
DMF (10 mL) was added K2CO3 (69.7 mg, 0.504 mmol) and 2-(l,3-dimethyl-lH-pyrazol- 4-yl)ethyl methanesulfonate (66.1 mg, 0.303 mmol). The mixture was stirred for 20 hours at 45 °C, diluted with water and ethyl acetate ( 30 mL), organic layer separated, washed with brine (20 mL), dried over Na2S04 and concentrated to obtain a crude product which was purified by silica gel chromatography eluting with ether acetate/ petroleum ether (from 10: 1 to 1 : 1) to afford isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH-pyrazol-4- yl)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'-yl)acetate (50 mg, 0.048 mmol, 47.3 % yield) as yellow oil. LCMS (M + H) = 618.2; Retention time (10 mM NH4HC03) = 2.363 min.
Step 2: To a solution of isopropyl (2S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetate (50 mg, 0.081 mmol) in methanol (10 mL) and water (2 mL) was added sodium hydroxide (9.71 mg, 0.243 mmol) and stirred for 20 hours at 100 °C. The mixture was concentrated under vacuo, diluted with HC1 (1N, 0.5 ml) and ethyl acetate (5ml). Organic layer separated and concentrated to give crude product which was purified by Prep-HPLC (Instrument Gilson 281 (PHG-009); Column Xtimate Prep C18 OBD, 21.2 x 250 mm, 10 pm; Mobile Phase A: Water (10 mM NH4HC03); B: MeCN; Gradient 40-68%B in 8.0 min, stop at 13.0 min; Flow Rate (ml/min) 30.00} to give (2S)-2-(tert-butoxy)-2-(5-(2-(l,3- dimethyl-lH-pyrazol-4-yl)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'- bipyridin]-5'-yl)acetic acid (29.2 mg, 0.051 mmol, 62.7 % yield) as white solid. LCMS (M + H) = 576.2; Retention time (10 mM NH4HC03) = 1.465 min.
Step 3 : The diastereomers of (2S)-2-(tert-butoxy)-2-(5-(2-(l,3-dimethyl-lH- pyrazol-4-yl)ethoxy)-6'-methyl-4'-(octahydroisoquinolin-2(lH)-yl)-[2,3'-bipyridin]-5'- yl)acetic acid (29.2 mg, 0.051 mmol) were separated by SFC [Column AD-H 4.6 x 100 mm; 5 pm; C o- Sol vent EtOH (l%ammonia/methanol)] to obtain
First eluting diastereomer 86: (4.2 mg, 7.08 pmol, 13.97 % yield). LCMS (M + H) = 576.2; Retention time (10 mM NH4HC03) = 1.476 min. ¾ NMR (400 MHz, MeOD) d 8.36 (d, J = 2.8 Hz, 1H), 8.11 (s, 1H), 7.56 (dd, J = 8.6, 2.9 Hz, 1H), 7.45 (d, J = 9.0 Hz, 2H), 5.81 (s, 1H), 4.25 (t, J = 6.6 Hz, 2H), 3.80 (s, 3H), 3.28- 2.78 (m, 4H), 2.66 (s, 3H), 2.25 (s, 3H), 1.86-1.30 (m, 14H), 1.19 (s, 9H) and
Second eluting diastereomer 87: (4.5 mg, 7.47 pmol, 14.73 % yield). LCMS (M + H) = 576.2; Retention time (10 mM NH4HC03) = 1.467 min. 1HNMR (400 MHz, MeOD) d 8.26 (d, J = 2.7 Hz, 1H), 8.02 (d, J = 8.1 Hz, 1H), 7.45 (dd, J = 8.6, 2.9 Hz, 1H), 7.34 (t, J = 11.4 Hz, 2H), 5.86 (s, 1H), 4.14 (t, J = 6.6 Hz, 2H), 3.68 (s, 3H), 3.15- 2.59 (m, 7H), 2.52 (s, 3H), 2.13 (s, 3H), 1.79-1.16 (m, 14H), 1.09 (s, 9H).
Biological Methods
Inhibition of HIV replication: A recombinant NL-RLuc proviral clone was constructed in which a section of the nef gene form NL4-3 was replaced with the Renilla Luciferase gene. This virus is fully infectious and can undergo multiple cycles of replication in cell culture. In addition, the luciferous reporter provides a simple and easy method for quantitating the extent of virus growth and consequently, the antiviral activity of test compounds. The plasmid pNLRLuc contains the proviral NL-Rluc DNA cloned into pUCl8 at the Pvull site. The NL-RLuc virus was prepared by transfection of 293T cells with the plasmid pNLRLuc. Transfections were performed using the LipofectAMINE PLUS kit form Invitrogen (Carlsbad, CA) according to the manufacturer and the virus generated was titered in MT-2 cells. For susceptibility analyses, the titrated virus was used to infect MT-2 cells in the presence of compound, and after 5 days of incubation, cells were processed and quantitated for virus growth by the amount of expressed luciferase. Assay media was RPMI 1640 supplemented with 10% heat inactivated fetal bovine serum (FBS), 100 units/ml penicillin G/100 units/ml streptomycin, 10 mM HEPES buffer pH 7.55 and 2 mM L-glutamine. The results form at least 2 experiments were used to calculate the EC50 values. Luciferase was quantitated using the Dual Luciferase kit form Promega (Madison, WI). Susceptibility of viruses to compounds was determined by incubation in the presence of serial dilutions of the compound. The 50% effective concentration (EC50) was calculated by using the exponential form of the median effect equation where (Fa) = l/[l+ (ED5o/drug conc.)m] (Johnson VA, Byington RT. Infectivity Assay. In Techniques in HIV Research ed. Aldovini A, Walker BD. 71-76. New York: Stockton Press.1990). Results are summarized in Table 1. Table 1.
Figure imgf000096_0001
Figure imgf000097_0001
Figure imgf000098_0001
ND: Not determined

Claims

CLAIMS We claim:
1. A compound of Formula I, or a pharmaceutically acceptable salt thereof,
Figure imgf000099_0002
I
wherein R3 is Ci-salkyl;
R4 is Ci-4alkyl;
R1 is pyridinyl or phenyl and is optionally substituted with 1 or 2 halogens;
Q is Ci-6alkyl optionally substituted with 1 to 3 halogens;
R5 is H, halo, phenyl, phenyl-O-, C3-6cycloalkyl, C3-6cycloalkyl-0-, Ci-6alkyl-0-, pyrazolyl, tetrahydropyranyl, or tetrahydrafuranyl, and is optionally substituted with 1-3 substituents independently selected from halogen and Ci-6alkyl;
R2 is
Figure imgf000099_0001
wherein R6 is Ci-6alkyl; R7 is C2-6alkyl, phenyl, -OCi-6alkyl, CN, or halogen; and R2 is optionally substituted with 1-3 substituents independently selected from halogen and Ci- 6alkyl.
2 A compound or salt according to Claim 1 wherein R3 is C3-5alkyl.
3. A compound or salt according to Claim 1 or Claim 2 wherein R4 is methyl or ethyl.
4. A compound or salt according to any of Claim 1-3 wherein R1 is pyridinyl and is optionally substituted with a fluorine.
5. A compound or salt according to any of Claims 1-4 wherein Q is Ci-6alkyl optionally substituted with 1-3 fluorines.
6. A compound or salt according to any of Claim 1-5 wherein R5 is optionally substituted with 1-3 substituents independently selected from F, Cl, and methyl.
7. A compound or salt according to any of Claims 1-6 wherein R2 is
Figure imgf000100_0001
wherein R6 is methyl; R7 is C2-3alkyl, phenyl, OCFb, CN, or F; and is optionally substituted with 1-2 substituents independently selected from F and CFb.
8. A pharmaceutical composition comprising a compound or salt according to any of Claims 1-7.
9. The composition of claim 8 further comprising at least one other agent used for treatment of AIDS or HIV infection selected from nucleoside HIV reverse transcriptase inhibitors, non-nucleoside HIV reverse transcriptase inhibitors, HIV protease inhibitors, HIV fusion inhibitors, HIV attachment inhibitors, CCR5 inhibitors, CXCR4 inhibitors, CAPSID inhibitors, HIV budding or maturation inhibitors, and HIV integrase inhibitors, and a pharmaceutically acceptable carrier.
10. A method for treating HIV infection comprising administering a composition according to Claim 8 to a patient in need thereof.
11. The method of claim 10 further comprising administering at least one other agent used for treatment of AIDS or HIV infection selected from nucleoside HIV reverse transcriptase inhibitors, non-nucleoside HIV reverse transcriptase inhibitors, HIV protease inhibitors, HIV fusion inhibitors, HIV attachment inhibitors, CCR5 inhibitors, CXCR4 inhibitors, CAPSID inhibitors, HIV budding or maturation inhibitors, and HIV integrase inhibitors.
12. A compound or pharmaceutically acceptable salt thereof according to any of Claims 1-7 for use in therapy
13. A compound or pharmaceutically acceptable salt thereof according to any of Claims 1-7 for use in treating HIV infection.
14. A compound or pharmaceutically acceptable salt thereof according to any of Claims 1-7 for use in the manufacture of a medicament for the treatment of HIV infection.
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