WO2022187206A1 - Dual-target mu opioid and dopamine d3 receptors ligands; preparation and use thereof - Google Patents

Dual-target mu opioid and dopamine d3 receptors ligands; preparation and use thereof Download PDF

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WO2022187206A1
WO2022187206A1 PCT/US2022/018287 US2022018287W WO2022187206A1 WO 2022187206 A1 WO2022187206 A1 WO 2022187206A1 US 2022018287 W US2022018287 W US 2022018287W WO 2022187206 A1 WO2022187206 A1 WO 2022187206A1
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compound
instance
alkyl
pain
independently
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Amy Hauck Newman
Alessandro BONIFAZI
Francisco O. BATTITI
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The United States Of America, As Represented By The Secretary, Department Of Health And Human Services
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
    • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D207/04—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having no double bonds between ring members or between ring members and non-ring members
    • C07D207/08—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having no double bonds between ring members or between ring members and non-ring members with hydrocarbon radicals, substituted by hetero atoms, attached to ring carbon atoms
    • C07D207/09—Radicals substituted by nitrogen atoms, not forming part of a nitro radical
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
    • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D207/04—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having no double bonds between ring members or between ring members and non-ring members
    • C07D207/10—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having no double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D207/12—Oxygen or sulfur atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D249/00—Heterocyclic compounds containing five-membered rings having three nitrogen atoms as the only ring hetero atoms
    • C07D249/02—Heterocyclic compounds containing five-membered rings having three nitrogen atoms as the only ring hetero atoms not condensed with other rings
    • C07D249/04—1,2,3-Triazoles; Hydrogenated 1,2,3-triazoles
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D295/00—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms
    • C07D295/04—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms with substituted hydrocarbon radicals attached to ring nitrogen atoms
    • C07D295/12—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms with substituted hydrocarbon radicals attached to ring nitrogen atoms substituted by singly or doubly bound nitrogen atoms
    • C07D295/125—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms with substituted hydrocarbon radicals attached to ring nitrogen atoms substituted by singly or doubly bound nitrogen atoms with the ring nitrogen atoms and the substituent nitrogen atoms attached to the same carbon chain, which is not interrupted by carbocyclic rings
    • 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
    • C07D401/02—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 two hetero rings
    • C07D401/12—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 two hetero rings linked by a chain containing hetero atoms as chain links

Definitions

  • the present disclosure is directed to dual-target Mu opioid (MOR) and dopamine D 3 receptors (D 3 R) ligands and their uses.
  • MOR dual-target Mu opioid
  • D 3 R dopamine D 3 receptors
  • MOR mu-opioid receptors
  • GPCR G- protein coupled receptors
  • Y 1 is -NH- or a piperazinyl group attached to the core structure and L 1 through the nitrogen atoms;
  • L 1 is a covalent bond or a linking group;
  • Y 2 is a covalent bond or a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms;
  • L 2 is a covalent bond or a linking group
  • Ar 1 is an aryl or a heteroaryl, wherein when Ar 1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents.
  • the disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein each instance of n independently is 0 or 1.
  • the disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein Ar 1 is substituted phenyl or optionally substituted pyridyl.
  • the disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein Ar 1 is wherein a is 1 or 2, and each instance of R 1 , R 2 , R 3 , and R 4 independently is hydrogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, hydroxyl, or halogen with the proviso that at least two of R 1 , R 2 , R 3 , and R 4 are other than hydrogen.
  • the disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein a) R 1 and R 4 are hydrogen and R 2 and R 3 are halogen; b) R 1 and R 4 are hydrogen, R 2 is halogen, and R 3 is C 1 -C 6 , alkyl; c) R 1 is hydrogen or hydroxyl, R 2 is C 1 -C 3 alkoxy, R 3 is halogen, and R 4 is C 1 -C 6 alkyl; d) R 5 is trifluoromethyl; or e) R 6 is ethyl and a is 1.
  • the disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein Y 1 is piperazinyl group and L 1 -Y 2 -L 2 is a covalent bond so that Y 1 Ar 1 .
  • Y 1 is -NH-;
  • L 1 is a linking group, wherein L 1 linking group is an alkyl chain containing 1, 2, 3, 4,
  • L 1 is a linking group, wherein L 1 linking group is -(CH 2 ) g - wherein g is 2, 3, 4, 5, 6,
  • Y 2 is a pyrrolidinyl or piperazinyl group
  • Z is N or CH; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
  • the disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein the compound is according to Formula (IB): Formula (IB) or a pharmaceutically acceptable salt thereof, wherein each instance of R a , n, and R x are as defined above for Formula (I); each instance of R c and R d independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C 3 -C 6 cycloalkyl, or a C 3 -C 6 cycloalkenyl;
  • Z is N or CH; each instance of R b independently is C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH 2 , C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, C 2 -C 6 alkanoyl, mono-C 1 -C 2 alkylamino, or di-C 1 -C 2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
  • the disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein the compound is according to Formula (IC):
  • Formula (IC) or a pharmaceutically acceptable salt thereof wherein each instance of R a , n, and R x are as defined above for Formula (I); each instance of R c and R d independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C 3 -C 6 cycloalkyl, or a C 3 -C 6 cycloalkenyl; x is 1 or 2;
  • Z is N or CH; each instance of R b independently is C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH 2 , C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, C 2 -C 6 alkanoyl, mono-C 1 -C 2 alkylamino, or di-C 1 -C 2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
  • the disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein the compound is according to Formula (ID): Formula (ID) or a pharmaceutically acceptable salt thereof, wherein each instance of R a , n, and R x are as defined above for Formula (I); each instance of R c and R d independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C 3 -C 6 cycloalkyl, or a C 3 -C 6 cycloalkenyl; x is 1 or 2;
  • Z is N or CH; each instance of R b independently is C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH 2 , C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, C 2 -C 6 alkanoyl, mono-C 1 -C 2 alkylamino, or di-C 1 -C 2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
  • R e is -C(O)NHR f ; or a C 1 to C 4 alkyl group substituted by wherein Ar 1 is aryl or a heteroaryl; wherein when Ar 1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents;
  • R s is H or CH3
  • R t is H or OH
  • R f is a C 1 to C4 alkyl group substituted by h is 1 or 2;
  • R t is H or OH; or a salt thereof.
  • the disclosure further provides compounds according to Formula (X), wherein R s is H and n is 1, and/or wherein R e is -C(O)NHR f .
  • R a , R f , R x , and n are defined as above for Formula (X); or a salt thereof.
  • the disclosure further provides a pharmaceutical composition comprising a compound as described in any preceding embodiment, and optionally a pharmaceutically acceptable carrier.
  • the disclosure further provides a method of treating pain, comprising providing to a patient in need thereof a therapeutically effective amount of at least one of the compounds as described in any preceding embodiment, optionally in the form of a pharmaceutical composition.
  • the pain to be treated is selected from the group consisting of acute pain, chronic pain, neuropathic pain, nociceptive pain, radicular pain, and combinations thereof.
  • the disclosure further provides a method of treating a disease or disorder that is treatable by the action of a dopamine D 3 receptor antagonist, a dopamine D 3 receptor partial agonist, a MOR agonist, a MOR partial agonist, or a combination of one or more of the foregoing, comprising providing to a patient in need thereof a therapeutically effective amount of at least one of the compounds as described in any preceding embodiment, optionally in the form of a pharmaceutical composition.
  • the disease or disorder to be treated is selected from the group consisting of substance use disorder (SUD), opioid use disorder (OUD), opioid addiction, and combinations thereof.
  • the disclosure further provides compounds according to Formula (I), wherein the compound is compound 13, 14, 15, 23, 28, 30, 31, 32, 40, or 48, as set out in Table 1 below, or a pharmaceutically acceptable salt thereof.
  • the disclosure further provides compounds according to Formula (X), wherein the compound is compound 74, 75, or 84 as described below, or a pharmaceutically acceptable salt thereof.
  • FIG. 1 illustrates drug design strategy based on structural modification of canonical synthons inspired by agonists, antagonists, and partial agonists selectively targeting MOR and D 3 R.
  • FIG. 2 shows the effects of intracranial (i.c.v.) microinjections of compound 28 or vehicle on thermal nociceptive responses as assessed by hot-plate test, compound 28 produced a dose-dependent increase in pain threshold (latency to sign of pain), indicating an analgesic effect produced by compound 28. Repeated injection of the same dose (20 mg) of compound 28 produced the same or similar analgesic effects in amplitude.
  • FIG. 3 shows the effects of intracranial (i.c.v.) microinjections of compound 28, morphine, or vehicle on open-field locomotion in mice, compound 28 failed to alter, while morphine produced a significant increase in locomotion.
  • FIG. 4 shows the effects of morphine (i.c.v.) or loperamide (i.p.) on thermal nociceptive response in mice. Intracranial microinjection of morphine produced a significant analgesic effect (left panel), while systemic administration of loperamide also produced an analgesic effect in a dose-dependent manner (right panel) as assessed by hot-plate test.
  • morphine i.c.v.
  • loperamide i.p.
  • FIG. 5 shows the effects of intranasal compound 28 on thermal nociceptive response in mice, compound 28 produced a dose-dependent analgesic effect as assessed by hot-plate test.
  • dual-target Mu opioid (MOR) and dopamine D 3 receptors (D 3 R) compounds (alternatively referred to as “dual-target MOR-D 3 R ligands” or “dual target compounds”), methods of preparation, and intermediates used in the preparation of such compounds.
  • dual-target means that a single compound (the “dual-target compound”) can act on more than one target, for example acting on both MOR and D 3 R.
  • uses of the novel compounds including use as potential non-addictive pharmacotherapeutics for pain management.
  • Dopamine D 3 receptor (D 3 R) antagonists and partial agonists are a “new” proposed class of ligands as therapeutics to attenuate opioid self-administration. It has recently been demonstrated that D 3 R antagonists and partial agonists look promising for the treatment of OUD (Jordan et al. “The highly selective dopamine D 3 R antagonist, R-VK4-40 attenuates oxycodone reward and augments analgesia in rodents” Neuropharmacology 2019, 158, 107597; You et al.
  • Dopamine D 3 R antagonist VK4-116 attenuates oxycodone self- administration and reinstatement without compromising its antinociceptive effects” Neuropsychopharmacology 2019, 44 (8), 1415-1424; Kumar et al. “Highly Selective Dopamine D 3 Receptor (D 3 R) Antagonists and Partial Agonists Based on Eticlopride and the D 3 R Crystal Structure: New Leads for Opioid Dependence Treatment” J Med Chem 2016, 59 (16), 7634-50.) Highly selective antagonists, such as VK4-116 (1) and VK4-40 (2) (FIG.
  • D 3 R antagonists/partial agonists do not potentiate the cardiovascular effects induced by cocaine or oxycodone in rats (Jordan et al. “Newly Developed Dopamine D3 Receptor Antagonists, R- VK4-40 and R-VK4-116, Do Not Potentiate Cardiovascular Effects of Cocaine or Oxycodone in Rats” J Pharmacol Exp Ther 2019, 371 (3), 602-614). In combination, these studies support the development of D 3 R antagonists/partial agonists to reduce the risk of opioid misuse and the consequent development of opioid use disorders.
  • D 3 R antagonism/partial agonism as an alternative and non-opioid approach for treatment of OUD, modulating the abuse potential of common prescription opioids (e.g., oxycodone) (Jordan et al. Neuropharmacology 2019; You et ah; Jordan et al. J Pharmacol Exp Ther 2019), combined with the well-established antinociceptive properties of MOR agonists, prompted the idea of generating a novel class of dual-target ligands directed to both MOR and D 3 R (FIG. 1).
  • common prescription opioids e.g., oxycodone
  • These dual-target compounds provide innovative and non-addictive pain management treatments for pain (e.g., acute and/or chronic pain). These compounds also provide for the development of pharmacological tools to study alternative receptor targets, different from opioid receptors, for reducing addiction liability of commonly prescribed analgesics; including development of pharmacological tools to study brain plasticity, physiology, and receptor cross-modulation pharmacology, in pain and addiction.
  • the general structure of the dual-target compounds involve a MOR Pharmacophore- Linker-D 3 R Pharmacophore where the MOR Pharmacophore provides agonism or partial agonism at MOR to provide an analgesic effect.
  • the D 3 R Pharmacophore provides antagonism or partial agonism at D 3 R for reducing addictive liability.
  • the dual-target compounds include those according to general Formula (I) and all sub-Formulas (IA), (IB), (IC), and (ID) as described herein.
  • Y 1 is -NH- or a piperazinyl group attached to the core structure and L 1 through the nitrogen atoms, specifically wherein when Y 1 is piperazinyl group and L 1 -Y 2 -L 2 is a covalent bond so that Y 1 Ar 1 ;
  • L 1 is a covalent bond or a linking group
  • Y 2 is a covalent bond or a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms, specifically a pyrrolidinyl or piperazinyl group;
  • L 2 is a covalent bond or a linking group; and Ar 1 is an aryl or a heteroaryl, wherein when Ar 1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents, specifically Ar 1 is substituted phenyl or optionally substituted pyridyl.
  • L 1 can be a covalent bond or a linking group, wherein the L 1 linking group is an alkyl chain containing 1, 2, 3, 4, 5, 6, 7, 8, 9 or more carbon atoms in the chain (the number of carbon atoms excluding pendant substitution), optionally including internal unsaturation, optionally an internal cycloalky group, optionally an internal heteroatom (e.g. O, N, S, or P, specifically an internal O (ether group) such as where L 1 is - (CH 2 ) y - O-(CH 2 ) y - where each y independently is 1, 2, 3, or more), optionally a substitution on the alkyl chain where the substitution is described herein (e.g.
  • oxo oxo
  • L 1 is linked to Y 2 via a heteroatom (e.g., O).
  • Exemplary internal cycloalkyl groups include cyclopropyl or cyclobutyl.
  • Y 2 can be a covalent bond or a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms, specifically a pyrrolidinyl or piperazinyl group.
  • Ar 1 is an aryl or a heteroaryl, wherein when Ar 1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents, specifically Ar 1 is substituted phenyl or optionally substituted pyridyl. In specific embodiments, Ar 1 is optionally substituted pyridyl, specifically pyridyl substituted with trifluoromethyl.
  • Ar 1 is wherein a is 1 or 2, and each instance of R 1 , R 2 , R 3 , and R 4 independently is hydrogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, hydroxyl, or halogen with the proviso that at least two of R 1 , R 2 , R 3 , and R 4 are other than hydrogen (i.e., the phenyl comprises at least two substituents).
  • R 1 and R 4 are hydrogen, R 2 and R 3 are halogen, specifically Cl.
  • R 1 and R 4 are hydrogen, R 2 is halogen, specifically Cl, and R 3 is C 1 -C 6 alkyl, specifically ethyl.
  • R 1 is hydrogen or hydroxyl;
  • R 2 is C 1 -C 3 alkoxy, specifically -OMe;
  • R 3 is halogen, specifically Cl, and
  • R 4 is C 1 -C 6 alkyl, specifically ethyl.
  • R 5 is trifluoromethyl.
  • R 6 is ethyl and a is 1.
  • Dual-target compounds within the general Formula (I) include compounds according to Formulas (IA), (IB), (IC), (ID):
  • each instance of R a , n, and R x are as defined above for Formula (I); each instance of R b independently is C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH 2 , C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, C 2 -C 6 alkanoyl, mono-C 1 -C 2 alkylamino, or di-C 1 -C 2 alkylamino;
  • Z is N or CH; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH; each instance of R c and R d independently is hydrogen, hydroxyl, or halogen, specifically F; m is 0, 1, 2, 3, or 4, specifically m is 1 or 2; t is 0, 1, 2, 3, or 4, specifically t is 1 or 2; is a single bond, a double bond, a C 3 -C 6 cycloalkyl, or a C 3 -C 6 cycloalkenyl, specifically a single bond; and x is 1 or 2, specifically 1.
  • Z is CH, it is understood that the carbon can be optionally substituted such that the hydrogen is replaced with a substituent as defined herein as suitable for substitution on A 1 .
  • R e is -C(O)NHR f ; or a C 1 to C4 alkyl group substituted by wherein Ar 1 has the meaning set out above;
  • R s is H or CH 3 ;
  • R t is H or OH
  • R f is a C 1 to C4 alkyl group substituted by wherein Ar 1 has the meaning set out above; h is 1 or 2; R t is H or OH; or a salt thereof.
  • R s is H.
  • R 1 is OH
  • H is 1 In an embodiment H is 2
  • each compound name includes the free acid or free base form of the compound as well hydrates of the compound and all pharmaceutically acceptable salts of the compound.
  • Formula (I) includes all subformulas thereof including Formulas (IA), (IB), (IC), and
  • the dual-target compounds may contain one or more asymmetric elements such as stereogenic centers, stereogenic axes and the like, e.g., asymmetric carbon atoms, so that the compounds can exist in different stereoisomeric forms.
  • asymmetric elements such as stereogenic centers, stereogenic axes and the like, e.g., asymmetric carbon atoms, so that the compounds can exist in different stereoisomeric forms.
  • These compounds can be, for example, racemates or optically active forms.
  • these compounds with two or more asymmetric elements these compounds can additionally be mixtures of diastereomers.
  • compounds having asymmetric centers it should be understood that all of the optical isomers and mixtures thereof are encompassed.
  • single enantiomers, i.e., optically active forms can be obtained by asymmetric synthesis, synthesis from optically pure precursors, or by resolution of the racemates.
  • Resolution of the racemates can also be accomplished, for example, by conventional methods such as crystallization in the presence of a resolving agent, or chromatography, using, for example, a chiral high-performance liquid chromatography (HPLC) column.
  • HPLC high-performance liquid chromatography
  • isotopes of atoms occurring in the present compounds are contemplated.
  • Isotopes include those atoms having the same atomic number but different mass numbers.
  • isotopes of hydrogen include tritium and deuterium; isotopes of carbon include 11 C, 13 C, and 14 C; and an isotope of fluorine includes 18 F.
  • active agent means a dual-target compound of the disclosed Formulas that when administered to a patient, alone or in combination with another compound, element, or mixture, confers, directly or indirectly, a physiological effect on the patient.
  • the indirect physiological effect may occur via a metabolite or other indirect mechanism.
  • the active agent is a compound, then salts, solvates (including hydrates) of the free compound, crystalline forms, non-crystalline forms, and any polymorphs of the compound are included. All forms are contemplated herein regardless of the methods used to obtain them.
  • a dash (“-") that is not between two letters or symbols is used to indicate a point of attachment for a substituent.
  • -(CH 2 )C 3 -C 8 cycloalkyl is attached through carbon of the methylene (CH 2 ) group.
  • alkyl means a branched or straight chain saturated aliphatic hydrocarbon group having the specified number of carbon atoms, generally from 1 to about 12 carbon atoms.
  • C 1 -C 6 alkyl as used herein indicates an alkyl group having from 1, 2, 3, 4, 5, or 6 carbon atoms.
  • Other embodiments include alkyl groups having from 1 to 8 carbon atoms, 1 to 4 carbon atoms or 1 or 2 carbon atoms, e.g. C 1 -C 6 alkyl, C 1 -C 4 alkyl, and C 1 -C 2 alkyl.
  • C 0 -C n alkyl When C 0 -C n alkyl is used herein in conjunction with another group, for example, (cycloalkyl)C 0 -C 4 alkyl, the indicated group, in this case cycloalkyl, is either directly bound by a single covalent bond (C 0 ), or attached by an alkyl chain having the specified number of carbon atoms, in this case 1, 2, 3, or 4 carbon atoms.
  • alkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, 3-methylbutyl, t- butyl, n-pentyl, and sec -pentyl.
  • alkoxy represents an alkyl group as defined above with the indicated number of carbon atoms attached through an oxygen bridge.
  • alkoxy include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, 2-butoxy, t-butoxy, n-pentoxy, 2-pentoxy, 3-pentoxy, isopentoxy, neopentoxy, n-hexoxy, 2-hexoxy, 3-hexoxy, and 3-methylpentoxy.
  • aryl means aromatic groups containing only carbon in the aromatic ring or rings. Typical aryl groups contain 1 to 3 separate, fused, or pendant rings and from 6 to about 18 ring atoms, without heteroatoms as ring members. When indicated, such aryl groups may be further substituted with carbon or non-carbon atoms or groups. Bicyclic aryl groups may be further substituted with carbon or non-carbon atoms or groups.
  • Bicyclic aryl groups may contain two fused aromatic rings (naphthyl) or an aromatic ring fused to a 5- to 7-membered non-aromatic cyclic group that optionally contains 1 or 2 heteroatoms independently chosen from N, O, and S, for example, a 3,4-methylenedioxy- phenyl group (e.g., a benzo[d] [1,3]dioxole).
  • Aryl groups include, for example, phenyl, naphthyl, including 1 -naphthyl and 2-naphthyl, and bi-phenyl.
  • cycloalkyl indicates a saturated hydrocarbon ring group, having only carbon ring atoms and having the specified number of carbon atoms, usually from 3 to about 8 ring carbon atoms, or from 3 to about 7 carbon atoms.
  • cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl as well as bridged or caged saturated ring groups such as norborane or adamantane.
  • cycloalkenyl means a saturated hydrocarbon ring group, comprising one or more unsaturated carbon-carbon bonds, which may occur in any stable point of the ring, and having the specified number of carbon atoms.
  • Monocyclic cycloalkenyl groups typically have from 3 to about 8 carbon ring atoms or from 3 to 7 (3, 4, 5, 6, or 7) carbon ring atoms.
  • Cycloalkenyl substituents may be pendant from a substituted nitrogen or carbon atom, or a substituted carbon atom that may have two substituents may have a cycloalkenyl group, which is attached as a spiro group.
  • Examples of cycloalkenyl groups include cyclopropenyl, cyclobutenyl, cyclopentenyl, or cyclohexenyl as well as bridged or caged saturated ring groups such as norbornene.
  • heteroaryl indicates a stable 5- to 7-membered monocyclic or 7- to 10-membered bicyclic heterocyclic ring which contains at least 1 aromatic ring that contains from 1 to 4, or specifically from 1 to 3, heteroatoms chosen from N, O, and S, with remaining ring atoms being carbon.
  • the total number of S and O atoms in the heteroaryl group exceeds 1, these heteroatoms are not adjacent to one another.
  • the total number of S and O atoms in the heteroaryl group is not more than 2, more specifically the total number of S and O atoms in the heteroaryl group is not more than 1.
  • a nitrogen atom in a heteroaryl group may optionally be quaternized.
  • heteroaryl groups may be further substituted with carbon or non-carbon atoms or groups.
  • substitution may include fusion to a 5 to 7-membered saturated cyclic group that optionally contains 1 or 2 heteroatoms independently chosen from N, O, and S, to form, for example, a [1,3]dioxolo[4,5-c]pyridyl group.
  • 5- to 6-membered heteroaryl groups are used.
  • heteroaryl groups include, but are not limited to, pyridyl, indolyl, pyrimidinyl, pyridizinyl, pyrazinyl, imidazolyl, oxazolyl, furanyl, thiophenyl, thiazolyl, triazolyl, tetrazolyl, isoxazolyl, quinolinyl, pyrrolyl, pyrazolyl, benz[b]thiophenyl, isoquinolinyl, quinazolinyl, quinoxalinyl, thienyl, isoindolyl, and 5, 6,7,8- tetrahydroisoquinoline.
  • Haloalkyl includes both branched and straight-chain alkyl groups having the specified number of carbon atoms, substituted with 1 or more halogen atoms, up to the maximum allowable number of halogen atoms.
  • Examples of haloalkyl include, but are not limited to, trifluoromethyl, difluoromethyl, 2-fluoroethyl, and penta-fluoroethyl.
  • Haloalkoxy is a haloalkyl group as defined herein attached through an oxygen bridge (oxygen of an alcohol radical).
  • Halo or “halogen” is any of fluoro, chloro, bromo, and iodo.
  • “Mono- and / or di-alkylamino” is a secondary or tertiary alkyl amino group, wherein the alkyl groups are independently chosen alkyl groups, as defined herein, having the indicated number of carbon atoms. The point of attachment of the alkylamino group is on the nitrogen. Examples of mono- and di-alkylamino groups include ethylamino, dimethylamino, and methyl-propyl- amino.
  • substituted means that any one or more hydrogens on the designated atom or group is replaced with a selection from the indicated group, provided that the designated atom’s normal valence is not exceeded.
  • an oxo group substitutes aromatic moieties, the corresponding partially unsaturated ring replaces the aromatic ring.
  • a pyridyl group substituted by oxo is a pyridone.
  • a stable compound or stable structure is meant to imply a compound that is sufficiently robust to survive isolation from a reaction mixture, and subsequent formulation into an effective therapeutic agent.
  • substituents are named into the core structure. For example, it is to be understood that when (cycloalkyl)alkyl is listed as a possible substituent the point of attachment of this substituent to the core structure is in the alkyl portion, or when arylalkyl is listed as a possible substituent the point attachment to the core structure is the alkyl portion.
  • Suitable groups that may be present on a “substituted” or “optionally substituted” position include, but are not limited to, halogen; cyano; hydroxyl; nitro; azido; alkanoyl (such as a C 2 -C 6 alkanoyl group such as acyl or the like); carboxamido; alkyl groups (including cycloalkyl groups) having 1 to about 8 carbon atoms, or 1 to about 6 carbon atoms; alkenyl and alkynyl groups including groups having one or more unsaturated linkages and from 2 to about 8, or 2 to about 6 carbon atoms; alkoxy groups having one or more oxygen linkages and from 1 to about 8, or from 1 to about 6 carbon atoms; aryloxy such as phenoxy; alkylthio groups including those having one or more thioether linkages and from 1 to about 8 carbon atoms, or from 1 to about 6 carbon atoms; alkylsulfinyl groups including those having one or
  • dosage form means a unit of administration of an active agent.
  • dosage forms include tablets, capsules, injections, suspensions, liquids, emulsions, creams, ointments, suppositories, inhalable forms, transdermal forms, and the like.
  • An exemplary dosage form is a solid oral dosage form.
  • compositions comprising at least one active agent, such as a dual-target compound or pharmaceutically acceptable salt thereof and at least one other substance, such as a carrier.
  • Pharmaceutical compositions meet the U.S. FDA’s GMP (good manufacturing practice) standards for human or non-human drugs.
  • the pharmaceutical compositions can be formulated into a dosage form.
  • salts of the present compounds can be synthesized from a parent compound that contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting free acid forms of these compounds with a stoichiometric amount of the appropriate base (such as Na, Ca, Mg, or K hydroxide, carbonate, bicarbonate, or the like), or by reacting free base forms of these compounds with a stoichiometric amount of the appropriate acid. Such reactions are typically carried out in water or in an organic solvent, or in a mixture of the two.
  • the appropriate base such as Na, Ca, Mg, or K hydroxide, carbonate, bicarbonate, or the like
  • salts of the present compounds further include solvates of the compounds and of the compound salts.
  • Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like.
  • the pharmaceutically acceptable salts include the conventional non-toxic salts and the quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids.
  • conventional non-toxic acid salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, mesylic, esylic, besylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, HOOC-(CH 2 ) n -COOH where n is 0-4, and the like. Lists of additional suitable salts may be found, e.g., in Remington’s Pharmaceutical Sciences, 17th, acid
  • a pharmaceutical composition comprises a dual-target compound or a pharmaceutically acceptable salt thereof and optionally further comprising a pharmaceutically acceptable carrier.
  • carrier refers to a diluent, excipient, or vehicle with which an active compound is provided.
  • compositions comprising a dual-target compound or pharmaceutically acceptable salt thereof, together with a pharmaceutically acceptable carrier.
  • the dual-target compound may be administered orally, topically, parenterally, by inhalation or spray, sublingually, transdermally, via buccal administration, rectally, as an ophthalmic solution, or by other means, in dosage unit formulations containing conventional pharmaceutically acceptable carriers.
  • the pharmaceutical composition may be formulated as any pharmaceutically useful form, e.g., as an aerosol, a cream, a gel, a pill, a capsule, a tablet, a syrup, a transdermal patch, a subcutaneous formulation, or an ophthalmic solution.
  • Some dosage forms, such as tablets and capsules can be subdivided into suitably sized unit doses containing appropriate quantities of the active components, e.g., an effective amount to achieve the desired purpose.
  • Carriers include excipients and diluents and must be of sufficiently high purity and sufficiently low toxicity to render them suitable for administration to the patient being treated.
  • the carrier can be inert or it can possess pharmaceutical benefits of its own.
  • the amount of carrier employed in conjunction with the compound is sufficient to provide a practical quantity of material for administration per unit dose of the compound.
  • Classes of carriers include, for example, buffering agents, coloring agents, diluents, disintegrants, emulsifiers, flavorants, glidants, lubricants, preservatives, stabilizers, surfactants, tableting agents, and wetting agents.
  • Some carriers may be listed in more than one class, for example vegetable oil may be used as a lubricant in some formulations and a diluent in others.
  • Exemplary pharmaceutically acceptable carriers include sugars, starches, celluloses, powdered tragacanth, malt, gelatin, talc, and vegetable oils.
  • compositions can be formulated for oral administration. These compositions can contain between 0.1 and 99 weight percent (“wt.%”) of a dual-target compound or pharmaceutically acceptable salt thereof, and usually at least about 5 wt.%. Some embodiments contain from about 25 wt.% to about 50 wt. % or from about 5 wt.% to about 75 wt.% of a compound of a dual-target compound.
  • the dual-target compound may be administered to the patient as a daily dosage regimen in unit dosage form one, two, three, or more times daily, specifically once daily.
  • Unit dosage forms for oral administration can contain about 0.5 mg to about 500 mg, specifically about 1 mg to about 400 mg, more specifically about 3 mg to about 200 mg, and yet more specifically about 5 mg to about 100 mg of the dual-target compound.
  • Unit dosage amounts for parenteral administration can contain about 0.1 mg to about 200 mg, specifically about 1 mg to about 100 mg, and more specifically about 2 to about 50 mg of the dual-target compound.
  • the dual-target compound can be administered to the patient for a period of time for acute therapy or for continuous therapy, for example one or more weeks, two or more weeks, three or more weeks, a month, two or more months, and the like.
  • the pharmaceutical composition can be formulated in a package or kit comprising the pharmaceutical composition containing a dual-target compound or a pharmaceutically acceptable salt thereof in a container and further comprising instructions for using the composition in order to elicit a therapeutic effect in a patient.
  • the pharmaceutical composition can also be formulated in a package or kit comprising the pharmaceutical composition of a dual-target compound or pharmaceutically acceptable salt thereof in a container and further comprising instructions for using the composition to treat a patient suffering from pain, including e.g., a dosing regimen.
  • a method for treating pain or eliciting an analgesic effect comprises providing an effective amount of a dual-target compound or pharmaceutically acceptable salt thereof to a patient in need of such treatment.
  • the dual-target compound or pharmaceutically acceptable salt thereof is provided in the form of a pharmaceutical composition.
  • the dual-target compounds provide safer non-addictive treatments for effective pain management.
  • the therapeutically effective amount of dual-target compounds may be lower than amounts of conventional opioids as the dopamine D 3 antagonist/partial agonist effect will potentiate the mu-opioid analgesic effect and possibly will prevent dose escalation for pain relief.
  • the selective dopamine D 3 receptor antagonist/partial agonist effect may mitigate the development of opioid addiction by eliminating the need for dose escalation and prevent the development of dependence and misuse.
  • Medical treatment can include treatment of an existing condition, such as a disease or disorder, prophylactic or preventative treatment, or diagnostic treatment.
  • providing means giving, administering, selling, distributing, transferring (for profit or not), manufacturing, compounding, or dispensing.
  • treating includes providing a therapeutically effective amount of a dual-target compound sufficient to prevent or inhibit or relieve pain; to provide analgesia.
  • terapéuticaally effective amount means an amount effective, when administered to a patient, to provide a therapeutic benefit, such as an amelioration of symptoms, e.g., to treat a patient suffering from pain, to provide analgesia, to mitigate the development of opioid addiction, and the like.
  • the pain to be treated by the methods is not particularly limiting and can include chronic pain, acute pain, breakthrough pain, post-operative pain, perioperative pain, mild pain, moderate pain, severe pain, bone and joint pain, soft tissue pain, nerve pain, pain due to a disease or disorder, pain due to trauma, neuropathic pain, nociceptive pain, radicular pain, and the like, and a combination thereof.
  • the compounds described herein have the advantage that they will have lower addictive liability compared to opioid agonists.
  • DA dopamine
  • D 2-like R dopamine D 2-like receptors
  • OUD opioid use disorders
  • CADD computer aided drug design
  • BRET bioluminescence resonance energy transfer
  • HEK 293 cells human embryonic kidney 293 cells
  • HPLC high performance liquid chromatography
  • HRMS high resolution mass spectrometry
  • DMA diichloromethane, methanol, ammonium hydroxide
  • EDC 1-Ethy1-3-(3-dimethylaminopropyl)carbodiimide
  • HOBt hydroxybenzotriazole
  • HCTU O-(1H-6-Chlorobenzotriazole-1-yl)-1,1,3,3- tetramethyluroniumhexafluorophosphate
  • DIPEA N,N-diisopropylethylamine
  • STAB sodium triacetoxyborohydride
  • DMP dess-martin periodinane
  • ACN acetonitrile
  • MOR agonists such as loperamide (3) (peripherally limited potent MOR agonist, FDA approved for anti-diarrhea treatment), and diphenoxylate (4), share similar structural motifs with the highly potent non-selective D 2 R/D 3 R antagonist haloperidol (5) (FIG. 1).
  • a substituted phenyl-piperazine and/or phenyl-piperidine synthon that was common to both classes of ligands was identified and modified to generate small molecules exploiting the structural similarities between MOR and D 3 R proteins, thus achieving dual-target binding.
  • Methadone (6) (FIG.
  • Bivalent dual-target analogs are those compounds where a MOR agonist primary pharmacophore (PP) is tethered with a D 3 R antagonist PP; both can bind their respective OBS, eliciting their corresponding opioid agonist and dopaminergic antagonist effects. Consistent with the definition of bitopic ligands (Newman et al., A., 2016 Philip S.
  • this D 3 R SP may also elicit binding interactions within the MOR SBP.
  • the novel class of dual-target compounds can be subdivided, as depicted in FIG. 1 (A-B), in three general templates: A) the N,N-dimethy 1-2,2-diphenyl acetamide, 2,2- diphenylacetonitrile, and 1,1-diphenylbutan-2-one MOR PPs, derived from loperamide (3), diphenoxylate (4), and methadone (6) respectively (FIG. 1), were tethered with suitably substituted PPs, inspired by selective and non-selective D 3 R antagonists (e.g., 1, 2, PG648 (7), eticlopride (8) and SB269,652 (9); FIG.
  • D 3 R antagonists e.g., 1, 2, PG648 (7), eticlopride (8) and SB269,652 (9)
  • 4-bromo-2,2-diphenylbutanenitrile was first N-alkylated with dimethylamine hydrochloride (Me 2 NH ⁇ HCl) under basic conditions, followed by hydrolysis of the nitrile in the presence of 48% HBr (aq solution) to yield the HBr salt of amino acid 17. Subsequent amidation mediated by EDC, HOBt, and 4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butan-1-amine yielded the desired product 18. Despite the importance of the alpha-methyl group of 6 being well reported in the literature (Goldberg et al.
  • 1,2,3,4-tetrahydroisoquinoline-7-carbonitrile is another common D 2 R-D 3 R antagonist PP fragment, present in well-characterized ligands, such as 9 (Kumar et al. “Synthesis and Pharmacological Characterization of Novel trans-Cyclopropylmethyl-Linked Bivalent Ligands That Exhibit Selectivity and Allosteric Pharmacology at the Dopamine D 3 Receptor (D 3 R)” J Med Chem 2017, 60 (4), 1478-1494; Kopinathan et al. “Subtle Modifications to the Indole-2-carboxamide Motif of the Negative Allosteric Modulator N-(( trans)-4-(2-(7-Cyano-
  • the injection port and transfer line temperatures were 250 and 280 °C, respectively, and the oven temperature gradient used was as follows: the initial temperature (70 °C) was held for 1 min and then increased to 300 °C at 20 °C/min and maintained at 300 °C for 4 min, total run time 16.5 min.
  • Column chromatography was performed using a Teledyne Isco CombiFlash RF flash chromatography system, or a Teledyne Isco EZ-Prep chromatography system.
  • Preparative thin layer chromatography was performed on Analtech silica gel plates (1000 ⁇ m). When %DMA is reported as eluting system, it stands for % of methanol in DCM, in presence of 0.5%-1% NH 4 OH.
  • Preparative chiral HPLC was performed using a Teledyne Isco EZ-Prep chromatography system with DAD (Diode Array Detector) and ELS detectors. HPLC analysis was performed using an Agilent Technologies 1260 Infinity system coupled with DAD (Diode Array Detector). For each analytical HPLC run multiple DAD ⁇ absorbance signals were measured in the range of 210-280 nm. Separation of the analyte, purity and enantiomeric/diastereomeric excess determinations were achieved at 40 °C using the methods reported in each detailed reaction description. Preparative and analytical HPLC columns were purchased from Daicel corporation or Phenomenex.
  • HPLC analysis method B Chiralpak OZ-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 30% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 9.072 and 10.862 min, purity >95%, er 43:57 (absorbance at 254 nm).
  • N,N-Dimethyl-4-(phenethylamino)-2,2-diphenylbutanamide (27).
  • a solution of 26 (90 mg, 0.32 mmol), 2-phenylethan-1-amine (77 mg, 0.64 mmol) and cat. AcOH in DCE (5 mL) was stirred at RT for 30 min.
  • STAB 9 mg, 0.48 mmol was added portion-wise and the mixture stirred for additional 2 h.
  • the solvent was removed under vacuum and the residue purified by flash chromatography eluting with 5% DMA.
  • the desired product was obtained as a colorless oil (quantitative yield).
  • HPLC analysis method A Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 11.906 and 12.953 min, purity >99%, er 38:62 (absorbance at 254 nm).
  • HPLC analysis method B Chiralcel OD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 12.011 min, purity >99% (absorbance at 254 nm).
  • HPLC analysis method C Chiralcel OZ-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 12.172 min, purity >95% (absorbance at 254 nm). The free base was converted into the corresponding oxalate salt.
  • HRMS C 32 H 40 O 2 N 4 CI 2 + H + ) calculated 583.26011, found 583.26204 (error 2.3 ppm).
  • HPLC analysis method A Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 20% 2- PrOH in hexanes; flow rate: 1 mL /min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL ; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 8.242 and 9.055 min, purity >99%, er 37:63 (absorbance at 254 nm).
  • HPLC analysis method B Chiralcel OD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210- 280 nm, Rt 8.516 and 9.788 min, purity >99%, er 57:43 (absorbance at 254 nm).
  • HPLC analysis method C Chiralcel OZ-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 8.886 and 9.524 min, purity >99%. er 50:50 (absorbance at 254 nm). The free base was converted into the corresponding oxalate salt. HRMS (C 34 H 45 O 2 N 4 CI + H + ) found 577.33059 (error 0.4 ppm).
  • HPLC analysis method B Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 10% 2- PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: -1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 9.043 min, purity >99%, ee >99% (absorbance at 254 nm).
  • HRMS C 31 H 34 N 3 O 3 CI + H + ) calculated 532.23615, found 532.23691 (error 0.4 ppm).
  • HPLC analysis method A Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: gradient from 10% to 40% 2- PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 22.362 min, purity >95%, ee >99% (absorbance at 254 nm).
  • HPLC analysis method B Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 30% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD a ⁇ bsorbance signals measured in the range of 210- 280 nm, Rt 14.389 min, purity >99%, ee >99% (absorbance at 254 nm).
  • the obtained crude material was dissolved in DCE (10 mL) and added to a solution of 26 (169 mg, 0.6 mmol) and catalytic AcOH in DCE (10 mL). The mixture was stirred for 10 min at RT and STAB (190 mg, 0.9 mmol) was added portionwise. The reaction was stirred for additional 12 h, the solvent was removed under vacuum and the residue purified by flash chromatography eluting with 10% DMA. The desired product was obtained as a colorless oil (80.5 mg, 21% yield).
  • HPLC analysis method A Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 30% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD a ⁇ bsorbance signals measured in the range of 210- 280 nm, Rt 9.538 and 10.664 min, purity >99%, er 46:54 (absorbance at 254 nm).
  • HPLC analysis method B Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 15% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ab ⁇ sorbance signals measured in the range of 210-280 nm, Rt 22.250 and 25.814 min, purity >99%, er 50:50 (absorbance at 254 nm).
  • HRMS C 37 H 49 N 4 O 4 CI + 2H 2+ found 325.18021, (C 37 H 49 N 4 O 4 CI + H + ) calculated 649.35151, found 649.35221 (error 1.0 ppm).
  • HPLC analysis method A Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 10% 2- PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD ⁇ absorbance signals measured in the range of 210-280 nm, Rt 20.539 and 23.859 min, purity >99%, er 51:49 (absorbance at 254 nm).
  • HRMS C 33 H 38 N 3 O 4 CI + H + ) calculated 576.26236, found 576.26297 (error 1.0 ppm).
  • HPLC analysis method Chiralpak AD-H analytical column (4.5mm x 250mm - 5 ⁇ m particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 ⁇ L; sample concentration: ⁇ 1 mg/mL; multiple DAD a ⁇ bsorbance signals measured in the range of 210-280 nm, Rt 18.518 min, purity >95%, ee >95% (absorbance at 210 nm). The free base was converted into the corresponding oxalate salt.
  • the compound was prepared following the same procedure described for compound 61 starting from tert-butyl (2S,4R)-4-((tert-butyldimethylsilyl)oxy)-2-((4-(6- (trifluoromethyl)pyridin-2-yl)piperazin-1-yl)methyl)pyrrolidine-l -carboxylate (0.62 g, 1.14 mmol).
  • the crude material obtained was used in the following step without further purification.
  • N,N-dimethyl-2,2-diphenylbutanamide (74) The desired product was prepared as described for compound 75, starting from (3R,5S)-5-((4-(2,3-dichlorophenyl)piperazin-1- yl)methyl)59yrrolidine-3-ol (780 mg, 2.37 mmol) and N,N-dimethyl-4-oxo-2,2- diphenylbutanamide (930 mg, 3.31 mmol), and isolated by preparative reverse phase HPLC (Phenomenex C-18 Gemini preparative HPLC column) eluting with a gradient starting from 10% ACN to 80% ACN in 2-PrOH + 0.1% TFA (flow rate 25-30 mL/min; injections of 4 mL at 15mg/mL) for a total run time of 60 min (324 mg, 17% yield).
  • HPLC Purenex C-18 Gemini preparative HPLC column
  • Analytical HPLC Agilent poroshell C-184.6 x 50 mm, 2.7 mm; gradient 10%-80% ACN in water + 0.1% TFA; 60 min run; injection 20 mL (1 mg/mL); temperature 40 C; Rt 22.862 min, purity >99% (at absorbance 1254 nm).
  • Analytical HPLC Agilent poroshell C-18 4.6 x 50 mm, 2.7 mm; gradient 10%-80% ACN in water + 0.1% TFA; 60 min run; injection 20 mL (1 mg/mL); temperature 40 C; Rt 22.013 min, purity >99% (at absorbance 1254 nm).
  • STAB cat. AcOH, DCE;
  • DMP DCM, from 0 C to room temperature;
  • STAB cat.
  • the desired product was isolated by preparative reverse phase HPLC (Phenomenex C-18 Gemini preparative HPLC column) eluting with a gradient starting from 10% ACN to 80% ACN in 2-PrOH + 0.1% TFA (flow rate 25-30 mL/min; injection of 4 mL - 5 mg/mL) for a total run time of 60 min (35 mg, 56% yield).
  • Scheme 15 a) NaN 3 , DMF; b) copper(II) sulfate pentahydrate, sodium ascorbate, hex-5-yn-1-ol, THF:H 2 O; c) DMP, DCM, from 0 C to room temperature; d) STAB, cat. AcOH, DCE; e) 3- bromoprop-1-yne, K 2 CO 3 , ACN, reflux; f) K 2 CO 3 , ACN, reflux.
  • N,N-dimethyl-2,2-diphenyl-4-(4-(6-(trifluoromethyl)pyridin-2-yl)piperazin-1- yl)butanamide (90) A solution of N-(3,3-diphenyldihydrofuran-2(3H)-ylidene)-N- methylmethanaminium bromide (1.0 g, 2.89 mmol), 1-(6-(trifluoromethyl)pyridm-2- yl)piperazine (0.668 g, 2.89 mmol) and K 2 CO 3 (2.0 g, 14.4 mmol) in ACN (20 mL) was stirred at reflux overnight.
  • Radioligand binding assays were conducted similarly as previously described (Battiti et al. 2019; Michino et al).
  • HEK293 cells stably expressing human D 2 LR or D 3 R or D4.4 were grown in a 50:50 mix of DMEM and Ham’s F12 culture media, supplemented with 20 mM HEPES, 2 mM L-glutamine, 0.1 mM non-essential amino acids, 1X antibiotic/antimycotic, 10% heat-inactivated fetal bovine serum, and 200 ⁇ g/mL hygromycin (Life Technologies, Grand Island, NY) and kept in an incubator at 37 °C and 5% CO 2 .
  • cells were harvested using premixed Earle’s balanced salt solution with 5 mM EDTA (Life Technologies) and centrifuged at 3000 rpm for 10 min at 21 °C. The supernatant was removed, and the pellet was resuspended in 10 mL hypotonic lysis buffer (5 mM MgCL, 5 mM Tris, pH 7.4 at 4 °C) and centrifuged at 14 500 rpm ( ⁇ 25000g) for 30 min at 4 °C. The pellet was then resuspended in binding buffer.
  • Bradford protein assay Bio-Rad, Hercules, CA was used to determine the protein concentration.
  • membranes were diluted to 500 ⁇ g/mL, in fresh EBSS binding buffer made from 8.7 g/L Earle’s Balanced Salts without phenol red (US Biological, Salem, MA), 2.2 g/L sodium bicarbonate, pH to 7.4, and stored in a -80 °C freezer for later use.
  • EBSS binding buffer made from 8.7 g/L Earle’s Balanced Salts without phenol red (US Biological, Salem, MA), 2.2 g/L sodium bicarbonate, pH to 7.4, and stored in a -80 °C freezer for later use.
  • EBSS binding buffer made from 8.7 g/L Earle’s Balanced Salts without phenol red (US Biological, Salem, MA), 2.2 g/L sodium bicarbonate, pH to 7.4, and stored in a -80 °C freezer for later use.
  • membranes were harvested fresh; the binding buffer was made from 50 mM Tris, 10 mM MgCl 2 , 1 mM
  • the reaction was terminated by filtration through PerkinElmer Uni-Filter-96 GF/B, presoaked for the incubation time in 0.5% polyethylenimine, using a Brandel 96-Well Plates Harvester Manifold (Brandel Instruments, Gaithersburg, MD). The filters were washed thrice with 3 mL (3 ⁇ 1 mL/well) of ice-cold binding buffer. PerkinElmer MicroScint 20 Scintillation Cocktail (65 ⁇ L) was added to each well, and filters were counted using a PerkinElmer MicroBeta Microplate Counter.
  • HEK293 cells stably expressing hMOR were grown in a DMEM medium, supplemented with 10% FBS, 2 mM L-glutamine, 1% penicillin-streptomycin (or antibiotic/antimycotic) and hygromycin B (50 ⁇ g/mL). Upon reaching confluence the cells were harvested and the membranes prepared as detailed before.
  • the binding buffer was made of 50 mM Tris and 5 mM MgCl 2 at pH 7.4. The experiments were performed in presence of [ 3 H]-DAMGO (final concentration 3 nM; Perkin Elmer) and 30 ⁇ g/well of membranes (final concentration). The reactions were incubated for 60 min at RT and terminated by rapid filtration through Perkin Elmer Uni-Filter-96 GF/B, presoaked for 60 min in 0.5% polyethylenimine. The non-specific binding was determined using 10 ⁇ M C-TOP, cold DAMGO, or Naloxone. The radioligand K d was measured via radioligand saturation experiments.
  • the extended linker compounds are reasonably well tolerated inside MOR.
  • Cells were seeded in 10 cm Petri dishes (2.5 x 10 6 cells per dish) and allowed to grow overnight in media at 37 °C, 5 % CO 2 . The following day, cells were transiently transfected in media supplemented with antibiotics (100 U/mL penicillin and 100 m g/mL streptomycin, Gibco) using a 1:6 total DNA to PEI (PolySciences Inc) ratio.
  • antibiotics 100 U/mL penicillin and 100 m g/mL streptomycin, Gibco
  • BRET constructs were as follows: 4 of Ngb33-Venus and 1 ⁇ g of mMOR-Rluc8 for Nb33 recruitment, 2 o ⁇ fg WT-G ⁇ (i2 or oA), 1 ⁇ g of G ⁇ 1 - Venus(156-239), 1 ⁇ g of G ⁇ 2- Venus( 1- 155), 1 ⁇ g of masGRK3ct-Rluc8 and 1 of receptor (SNAP-mMOR or hD 3 R) for GPA (Hollins et al.
  • the cells were washed once with D-PBS and incubated with ligands in D-PBS (supplemented with 10 mM glucose) at 37 °C, 5 % CO 2 for 3h prior to starting the assay.
  • D-PBS supplemented with 10 mM glucose
  • the Rluc substrate coelenterazine h was added to each well (final concentration of 5 pM) and cells were incubated for 5 minutes at 37 °C.
  • ligands final concentration from 10 pM to 1 nM in D-PBS
  • ligands final concentration from 10 pM to 1 nM in D-PBS
  • cells were incubated for a further 10 minutes at 37 °C before reading the plate in a PHERAstar FSX microplate reader (Venus and Rluc emission signals at 535 and 475 nm respectively, BMG Labtech).
  • the ratio of Venus:Rluc counts was used to quantify the BRET signal in each well.
  • Data were normalized to the wells containing 10 pM DAMGO/quinpirole or no drug for maximal or minimal response, respectively and as indicated in the figure legends. All experiments were performed in duplicate and at least three times independently.
  • the ability of the ligands to induce the active state of the MOR was determined by measuring recruitment of a conformationally selective nanobody that recognizes and binds to the active conformation of MOR, nanobody 33 (Nb33) (Sounier et al. “Propagation of conformational changes during mu-opioid receptor activation” Nature 2015, 524 (7565), 375-8).
  • Nb33 nanobody 33
  • Four of the newly synthesized MOR-D 3 R hybrids 14, 23, 28, 40 were tested.
  • the efficacious agonists DAMGO D-Ala2, N-MePhe4, Gly5-ol-enkephalin
  • quinpirole and dopamine were used as reference agonists to normalize data at the MOR and D 3 R, respectively.
  • MOR partial agonist morphine was included to illustrate the relative coupling efficiency and amplification of the different assays. Both known antagonists, naloxone (MOR) and 5 (D 3 R), inhibited agonist- stimulated GPA in a concentration-dependent manner.
  • Biased agonism analysis for MOR signaling pathways All data represent the mean of at least three independent experiments, each performed in duplicate. Transduction coefficients and bias factors were calculated using the Black and Leff operational model of agonism using DAMGO as the reference, balanced ligand. To perform the bias analysis, each individual concentration-response curve was fitted to the following form of the operational model of agonism (Black et al. “An operational model of pharmacological agonism: the effect of E/[A] curve shape on agonist dissociation constant estimation” Br J Pharmacol 1985, 84 (2), 561-71) to allow the quantification of biased agonism:
  • E m is the maximal possible response of the system
  • basal is the basal level of response
  • [A] is the molar concentration of each agonist
  • K represents the equilibrium dissociation constant of the agonist
  • ⁇ is an index of the signaling efficacy of the agonist that is defined as R T /K E , where R T is the total number of receptors and Kr is the coupling efficiency of each agonist-occupied receptor
  • n is the slope of the transducer function that links occupancy to response.
  • the log( ⁇ /K A ) value of a reference agonist in this case DAMGO
  • DAMGO the log( ⁇ /K A ) value of a reference agonist
  • the relative bias can then be calculated for each ligand at the two different signaling pathways by subtracting the ⁇ log( ⁇ /K A ) of one pathway from the other to give a ⁇ log( ⁇ /K A ) value, which is a measure of bias.
  • a lack of biased agonism will result in values of ⁇ log( ⁇ /k A ) not significantly different from 0 between pathways.
  • pooled_SEM is the calculated error for the difference
  • SE j 1 and SE j 2 is the individual uncorrelated/random error values used to propag the pooled SEM value.
  • MOR-D 3 R dual-target ligands The data obtained highlight a series of hit to lead candidates as MOR-D 3 R dual-target ligands.
  • Multiple combinations of bivalent or bitopic ligands were synthesized based on carefully designed structural modifications and in silico guided SAR around the MOR PP, D 3 R PP and SP, as well as linkers, with a particular focus on regio- and stereochemistry.
  • Compounds were identified with a range of sub-nanomolar to sub-micromolar binding affinities for each receptor of interest and thus provide a new approach to modulate the pharmacological profiles of highly selective MOR agonists through concomitant dual-target D 3 R antagonism.
  • Intracerebroventricular (i.c.v.) microinjection Male adult (25-30 g) wild- type mice with C57BL/6J genetic backgrounds, purchased from Jaxson’s Laboratory, were individually housed and maintained on a 12-h light/dark cycle with free access to food and water. Under ketamine + xylazine anesthesia (100 mg/kg + 10 mg/kg, i.p.), mouse was implanted with a 30-gauge stainless steel guide cannula unilaterally into a lateral ventricle (coordinates: +0.3 mm posterior to bregma, 1.0 mm lateral to midline, and -3.0 mm ventral to the surface of the cortex). After 5-7 days of recovery from surgery the experiments began.
  • Each animal received 2-3 drug injections during the experiments with 3-5 days of time intervals. The order of drug injections was counterbalanced.
  • Hot-plate test Nociceptive tests were be performed using a hot plate device (Model 39, IITC Life Science Inc., Woodland Hills, CA, USA). See FIGS. 2, 4, 5. Briefly, mice were placed inside a transparent cage on the hot plate, which was pre-heated to 52 ( ⁇ 0.2) °C.
  • mice were habituated to locomotor detection chambers (Accuscan Instruments, Columbus, OH, USA) for 2 ⁇ 3 days (3 hours per day). On the test day, mice were placed in the chamber for 1 h of habituation (baseline), and then each animal received one dose of morphine, compound 28 or vehicle (saline, i.c.v.). Next, mice were placed back in the open-field apparatus and locomotor activity was measured over a 2 h period. The order of the injections was counterbalanced. The time intervals between the drug tests were 3-5 days. The distance traveled before and after injections was collected in 10-min intervals using the VersaMax data analysis system (Accuscan Instruments).
  • compositions, methods, or formulae may alternatively comprise, consist of, or consist essentially of, any appropriate components or steps herein disclosed.
  • the invention may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants, species, or steps used in the prior art compositions, methods, or formulae, or that are otherwise not necessary to the achievement of the function and/or objectives of the present claims.
  • endpoints of all ranges directed to the same component or property are inclusive of the endpoints, are independently combinable, and include all intermediate points and ranges (e.g., ranges of “up to about 25 wt.%, or, more specifically, about 5 wt.% to about 20 wt.%,” is inclusive of the endpoints and all intermediate values of the ranges of “about 5 wt.% to about 25 wt.%,” such as about 10 wt% to about 23 wt%, etc.).

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Abstract

Disclosed herein are novel dual-target compounds that bind at both the mu-opioid receptor (MOR) and dopamine D3 receptors (D3R) to provide MOR-mediated analgesia, while minimizing addictive liability through D3R antagonism/partial agonism. The novel compounds are useful in the treatment of pain and substance use disorder.

Description

DUAL-TARGET MU OPIOID AND DOPAMINE D3 RECEPTORS LIGANDS; PREPARATION AND USE THEREOF
HELD OF THE DISCLOSURE The present disclosure is directed to dual-target Mu opioid (MOR) and dopamine D3 receptors (D3R) ligands and their uses.
BACKGROUND
Until now, the main target for pain-management therapies and drug development has been the opioid system, and in particular the mu-opioid receptors (MOR), belonging to the G- protein coupled receptors (GPCR) family. However, the most common MOR agonists used in pain therapy suffer from a high potential for abuse and development of tolerance. Opioid agonists are largely ineffective in long-term pain therapy, such as chronic pain therapy.
Over the last decade, the United States has faced a devastating opioid epidemic with an estimate of over 130 people dying from opioid overdose every day (CDC/NCHS National Vital Statistics System, Mortality. CDC WONDER, Atlanta, GA: US Department of Health and Human Services, CDC). The misuse and often consequent addiction to opioids (e.g., prescription pain relievers, and synthetic opioids in general) is a serious national health, social, and economic emergency. Coupled with the novel coronavirus pandemic, the mortality rate involving opioid overdose is rising, and the need for new therapeutic strategies is more urgent than ever (Silva et al. “The Escalation of the Opioid Epidemic Due to COVID- 19 and Resulting Lessons About Treatment Alternatives” The American loumal of Managed Care 2020, 26 (7)). According to recent reports, >20% of patients being treated for chronic pain will misuse their opioid prescriptions, and 8-12% develop opioid use disorders (OUD) (Vowles et al. “Rates of opioid misuse, abuse, and addiction in chronic pain: a systematic review and data synthesis” Pain 2015, 156 (4), 569-76). Ultimately, an estimated 5% of patients is reported to transition from misuse of prescription opioids to heroin (Muhuri et al. “Associations of Nonmedical Pain Reliever Use and Initiation of Heroin Use in the United States” CBHSQ Data Rev. August 2013; Cicero et al. “The changing face of heroin use in the United States: a retrospective analysis of the past 50 years” JAMA Psychiatry 2014, 71 (7), 821-6; Carlson et al. “Predictors of transition to heroin use among initially non-opioid dependent illicit pharmaceutical opioid users: A natural history study” Drug Alcohol Depend 2016, 160, 127-34), or other synthetic opioids.
Therefore, there remains a need in the art for safer methods of pain management using new therapeutics that provide effective analgesia with reduced abuse liability. SUMMARY
The present disclosure provides compounds according to Formula (I):
Figure imgf000003_0001
or pharmaceutically acceptable salts thereof, wherein
Rx is CN or -(C=O)-N(Rz)2 wherein each instance of Rz independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, or C2-C6 alkanoyl; each instance of Ra independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; each instance of n independently is 0, 1, 2, or 3;
Y1 is -NH- or a piperazinyl group attached to the core structure and L1 through the nitrogen atoms; L1 is a covalent bond or a linking group;
Y2 is a covalent bond or a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms;
L2 is a covalent bond or a linking group; and
Ar1 is an aryl or a heteroaryl, wherein when Ar1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents.
The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein Rx is - (C=O)-N(Rz)2 wherein each instance of Rz independently is C1-C6 alkyl.
The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein each instance of n independently is 0 or 1.
The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein Ar1 is substituted phenyl or optionally substituted pyridyl. The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein Ar1 is
Figure imgf000004_0001
wherein a is 1 or 2, and each instance of R1, R2, R3, and R4 independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy, hydroxyl, or halogen with the proviso that at least two of R1, R2, R3, and R4 are other than hydrogen.
The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein a) R1 and R4 are hydrogen and R2 and R3 are halogen; b) R1 and R4 are hydrogen, R2 is halogen, and R3 is C1-C6, alkyl; c) R1 is hydrogen or hydroxyl, R2 is C1-C3 alkoxy, R3 is halogen, and R4 is C1-C6 alkyl; d) R5 is trifluoromethyl; or e) R6 is ethyl and a is 1.
The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein Y1 is piperazinyl group and L1-Y2-L2 is a covalent bond so that Y1Ar1.
The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein
Y1 is -NH-; L1 is a linking group, wherein L1 linking group is an alkyl chain containing 1, 2, 3, 4,
5, 6, 7, 8, 9 or more carbon atoms in the chain, optionally including internal unsaturation, optionally an internal cycloalky group, optionally an internal heteroatom, optionally a substitution on the alkyl chain, and optionally wherein L1 is linked to Y2 via a heteroatom; Y2 is a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms; and
L2 is a linking group, wherein L2 linking group is an alkyl chain containing 1, 2, 3, 4, 5, 6, 7, 8, 9 or more carbon atoms in the chain, wherein the alkyl chain is linked to Ar1 through a covalent bond, O, S, NRy, -(C=O)-, C(RW)2, N(Ry)- (C=O)-, -(C=O)-N(Ry), -O-(C=O)-O-, -O-(C=O)-N(Ry)-, -N(Ry)-(C=O)-O-, or -N(Ry)-(C=O)-N(Ry)-; each instance of Ry independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, or C2-C6 alkanoyl; and each instance of Rw independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino. The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein Y1 is -NH-;
L1 is a linking group, wherein L1 linking group is -(CH2)g- wherein g is 2, 3, 4, 5, 6,
7, or 8; -(CH2)f-CH=CH-(CH2)f- wherein each instance of f independently is
1, 2, or 3; or
Figure imgf000005_0002
wherein each instance of f independently is 1, 2, or 3; optionally wherein L1 is linked to Y2 via O;
Y2 is a pyrrolidinyl or piperazinyl group;
L2 is a linking group, wherein L2 linking group is an alkyl chain containing 1 or 2 carbon atoms wherein the alkyl chain is linked to Ar1 through N(Ry)-(C=O)- or -(C=O)-N(Ry); and each instance of Ry independently is hydrogen or C1-C6 alkyl.
The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein the compound is according to Formula (IA):
Formula (IA)
Figure imgf000005_0001
or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I);
Z is N or CH; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH. The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein the compound is according to Formula (IB): Formula (IB)
Figure imgf000006_0001
or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I); each instance of Rc and Rd independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C3-C6 cycloalkyl, or a C3-C6 cycloalkenyl;
Z is N or CH; each instance of Rb independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH. The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein the compound is according to Formula (IC):
Formula (IC)
Figure imgf000006_0002
or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I); each instance of Rc and Rd independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C3-C6 cycloalkyl, or a C3-C6 cycloalkenyl; x is 1 or 2;
Z is N or CH; each instance of Rb independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
The disclosure further provides compounds according to Formula (I) or pharmaceutically acceptable salts thereof of any preceding embodiment, wherein the compound is according to Formula (ID):
Figure imgf000007_0001
Formula (ID) or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I); each instance of Rc and Rd independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C3-C6 cycloalkyl, or a C3-C6 cycloalkenyl;
Figure imgf000007_0002
x is 1 or 2;
Z is N or CH; each instance of Rb independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
The disclosure further provides compounds according to Formula (X)
Figure imgf000008_0001
wherein Rx is CN or -(C=O)-N(Rz)2 wherein each instance of Rz independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, or C2-C6 alkanoyl; each instance of Ra independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; each instance of n independently is 0, 1, 2, or 3;
Re is -C(O)NHRf; or a C1 to C4 alkyl group substituted by
Figure imgf000008_0002
wherein Ar1 is aryl or a heteroaryl; wherein when Ar1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents;
Rs is H or CH3; and
Rt is H or OH;
Rf is a C1 to C4 alkyl group substituted by
Figure imgf000008_0003
h is 1 or 2;
Rt is H or OH; or a salt thereof.
The disclosure further provides compounds according to Formula (X), wherein Rs is H and n is 1, and/or wherein Re is -C(O)NHRf.
The disclosure further provides compounds according to Formula (XI)
Figure imgf000009_0001
wherein Ra, Rf, Rx, and n are defined as above for Formula (X); or a salt thereof. The disclosure further provides a pharmaceutical composition comprising a compound as described in any preceding embodiment, and optionally a pharmaceutically acceptable carrier.
The disclosure further provides a method of treating pain, comprising providing to a patient in need thereof a therapeutically effective amount of at least one of the compounds as described in any preceding embodiment, optionally in the form of a pharmaceutical composition. The disclosure further provides that the pain to be treated is selected from the group consisting of acute pain, chronic pain, neuropathic pain, nociceptive pain, radicular pain, and combinations thereof.
The disclosure further provides a method of treating a disease or disorder that is treatable by the action of a dopamine D3 receptor antagonist, a dopamine D3 receptor partial agonist, a MOR agonist, a MOR partial agonist, or a combination of one or more of the foregoing, comprising providing to a patient in need thereof a therapeutically effective amount of at least one of the compounds as described in any preceding embodiment, optionally in the form of a pharmaceutical composition. The disclosure further provides that the disease or disorder to be treated is selected from the group consisting of substance use disorder (SUD), opioid use disorder (OUD), opioid addiction, and combinations thereof.
The disclosure further provides compounds according to Formula (I), wherein the compound is compound 13, 14, 15, 23, 28, 30, 31, 32, 40, or 48, as set out in Table 1 below, or a pharmaceutically acceptable salt thereof. The disclosure further provides compounds according to Formula (X), wherein the compound is compound 74, 75, or 84 as described below, or a pharmaceutically acceptable salt thereof. BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 illustrates drug design strategy based on structural modification of canonical synthons inspired by agonists, antagonists, and partial agonists selectively targeting MOR and D3R. FIG. 2 shows the effects of intracranial (i.c.v.) microinjections of compound 28 or vehicle on thermal nociceptive responses as assessed by hot-plate test, compound 28 produced a dose-dependent increase in pain threshold (latency to sign of pain), indicating an analgesic effect produced by compound 28. Repeated injection of the same dose (20 mg) of compound 28 produced the same or similar analgesic effects in amplitude. FIG. 3 shows the effects of intracranial (i.c.v.) microinjections of compound 28, morphine, or vehicle on open-field locomotion in mice, compound 28 failed to alter, while morphine produced a significant increase in locomotion.
FIG. 4 shows the effects of morphine (i.c.v.) or loperamide (i.p.) on thermal nociceptive response in mice. Intracranial microinjection of morphine produced a significant analgesic effect (left panel), while systemic administration of loperamide also produced an analgesic effect in a dose-dependent manner (right panel) as assessed by hot-plate test.
FIG. 5 shows the effects of intranasal compound 28 on thermal nociceptive response in mice, compound 28 produced a dose-dependent analgesic effect as assessed by hot-plate test. DETAILED DESCRIPTION
Disclosed are dual-target Mu opioid (MOR) and dopamine D3 receptors (D3R) compounds (alternatively referred to as “dual-target MOR-D3R ligands” or “dual target compounds”), methods of preparation, and intermediates used in the preparation of such compounds. The term “dual-target” means that a single compound (the “dual-target compound”) can act on more than one target, for example acting on both MOR and D3R. Further disclosed are uses of the novel compounds including use as potential non-addictive pharmacotherapeutics for pain management.
Dopamine D3 receptor (D3R) antagonists and partial agonists are a “new” proposed class of ligands as therapeutics to attenuate opioid self-administration. It has recently been demonstrated that D3R antagonists and partial agonists look promising for the treatment of OUD (Jordan et al. “The highly selective dopamine D3R antagonist, R-VK4-40 attenuates oxycodone reward and augments analgesia in rodents” Neuropharmacology 2019, 158, 107597; You et al. “Dopamine D3R antagonist VK4-116 attenuates oxycodone self- administration and reinstatement without compromising its antinociceptive effects” Neuropsychopharmacology 2019, 44 (8), 1415-1424; Kumar et al. “Highly Selective Dopamine D3 Receptor (D3R) Antagonists and Partial Agonists Based on Eticlopride and the D3R Crystal Structure: New Leads for Opioid Dependence Treatment” J Med Chem 2016, 59 (16), 7634-50.) Highly selective antagonists, such as VK4-116 (1) and VK4-40 (2) (FIG. 1), attenuate oxycodone self-administration and reinstatement to drug seeking, without compromising oxycodone’s antinociceptive effects, in rodents. Importantly, these D3R antagonists/partial agonists do not potentiate the cardiovascular effects induced by cocaine or oxycodone in rats (Jordan et al. “Newly Developed Dopamine D3 Receptor Antagonists, R- VK4-40 and R-VK4-116, Do Not Potentiate Cardiovascular Effects of Cocaine or Oxycodone in Rats” J Pharmacol Exp Ther 2019, 371 (3), 602-614). In combination, these studies support the development of D3R antagonists/partial agonists to reduce the risk of opioid misuse and the consequent development of opioid use disorders.
Due to the abuse liability and development of tolerance associated with the most common MOR agonists used in pain therapy, including chronic pain, for which opioid agonists are largely ineffective in the long-term (Rosenblum et al. “Opioids and the treatment of chronic pain: controversies, current status, and future directions” Exp Clin Psychopharmacol 2008, 16 (5), 405-16; Kaye et al. “Prescription Opioid Abuse in Chronic Pain: An Updated Review of Opioid Abuse Predictors and Strategies to Curb Opioid Abuse: Part 1.” Pain Physician 2017, 20 (2S), S93-S109; Morrone et al. “Opioids Resistance in Chronic Pain Management” Curr Neuropharmacol 2017, 15 (3), 444-456.), research efforts have been directed toward identifying specific physiological responses associated with MOR agonists’ cellular activation pathways. Functionally biased agonists have been posited to reduce the side effect profile of classic opioid analgesics and augment their utility not only as analgesics, but also in the treatment of OUD (Schmid et al. “Bias Factor and Therapeutic Window Correlate to Predict Safer Opioid Analgesics” Cell 2017, 171 (5), 1165-1175 el3; Grim et al. “Toward Directing Opioid Receptor Signaling to Refine Opioid Therapeutics” Biol Psychiatry 2020, 87 (1), 15-21; Bossert et al. “Role of mu, but not delta or kappa, opioid receptors in context-induced reinstatement of oxycodone seeking” Eur J Neurosci 2019, 50 (3), 2075-2085; Grim et al. “A G protein signaling-biased agonist at the mu-opioid receptor reverses morphine tolerance while preventing morphine withdrawal” Neuropsychopharmacology 2020, 45 (2), 416-425.).
Design, synthesis, and pharmacological characterization of signaling-pathway biased agonists targeting the mu-opioid receptors (MOR) allowed for the identification of highly selective G-protein biased agonists, with limited activation of Beta-arrestin pathways, highlighting different physiological effects mediated by each independent pathway (Schmid et al.; Kennedy et al. “Optimization of a Series of Mu Opioid Receptor (MOR) Agonists with High G Protein Signaling Bias” J Med Chem 2018, 61 (19), 8895-8907.)· It has been suggested that the MOR G-protein pathway seems to be the predominant mediator of the analgesic effects of MOR agonists, meanwhile it has been posited that the simultaneous hindering of Beta-arrestin recruitment might reduce the respiratory depression and other side effects, such as constipation, associated with opioid-like drugs (Imam et al. “Intracerebroventricular administration of CYX-6, a potent mu-opioid receptor agonist, a delta- and kappa-opioid receptor antagonist and a biased ligand at mu, delta & kappa-opioid receptors, evokes antinociception with minimal constipation and respiratory depression in rats in contrast to morphine” Eur J Pharmacol 2020, 871, 172918; Kliewer et al. “Phosphorylation-deficient G-protein-biased mu-opioid receptors improve analgesia and diminish tolerance but worsen opioid side effects” Nat Commun 2019, 10 (1), 367; Montandon et al. “G-protein-gated Inwardly Rectifying Potassium Channels Modulate Respiratory Depression by Opioids” Anesthesiology 2016, 124 (3), 641-50; Levitt et al. “mu opioid receptor activation hyperpolarizes respiratory-controlling Kolliker-Fuse neurons and suppresses post-inspiratory drive” J Physiol 2015, 593 (19), 4453-69; Galligan et al. “Molecular physiology of enteric opioid receptors” Am J Gastroenterol Suppl 2014, 2 (1), 17-21.). However, this has been a topic of intensive investigation, and recently it has been reported that classical MOR agonists, such as morphine and fentanyl, induce dose-dependent respiratory depression and constipation in Beta-arrestin2 knock-out mice, similarly to what is observed in wild-type mice (Kliewer et al. “Morphine-induced respiratory depression is independent of beta-arrestin2 signalling” Br J Pharmacol 2020; Imam et al. “Progress in understanding mechanisms of opioid-induced gastrointestinal adverse effects and respiratory depression” Neuropharmacology 2018, 131, 238-255; Gillis et al. “Low intrinsic efficacy for G protein activation can explain the improved side effect profiles of new opioid agonists” Sci Signal 2020, 13 (625)). Subsequent pharmacological evaluation has also shown that MOR G- protein biased agonists still have abuse potential (Kliewer et al.; Negus et al. “Abuse Potential of Biased Mu Opioid Receptor Agonists” Trends Pharmacol Sci 2018, 39 (11), 916- 919; Altarifi et al. “Effects of acute and repeated treatment with the biased mu opioid receptor agonist TRV130 (oliceridine) on measures of antinociception, gastrointestinal function, and abuse liability in rodents” J Psychopharmacol 2017, 31 (6), 730-739; Austin Zamarripa et al. “The G-protein biased mu-opioid agonist, TRV130, produces reinforcing and antinociceptive effects that are comparable to oxycodone in rats” Drug Alcohol Depend 2018, 192, 158-162). It is still unclear whether the optimal outcome and pharmacotherapeutic potential of MOR agonists can be gained through selective activation of a particular downstream signaling pathway (functional selectivity) or whether an optimal level partial agonism at multiple pathways may instead provide a route for the development of safer opioids (Gillis et ah; Julie et al. “Opioid pharmacology under the microscope” Mol Pharmacol 2020). Independent of the signaling pathways and cellular mechanisms associated with respiratory depression and constipation, abuse liability remains as a serious concern that must be addressed with different drug design approaches.
The recognition of D3R antagonism/partial agonism as an alternative and non-opioid approach for treatment of OUD, modulating the abuse potential of common prescription opioids (e.g., oxycodone) (Jordan et al. Neuropharmacology 2019; You et ah; Jordan et al. J Pharmacol Exp Ther 2019), combined with the well-established antinociceptive properties of MOR agonists, prompted the idea of generating a novel class of dual-target ligands directed to both MOR and D3R (FIG. 1). Not wishing to be bound by theory, compounds that are both MOR agonists/partial agonists and D3R antagonist/partial agonists would have analgesic activity without concomitant abuse liability. This approach aimed at maintaining the analgesic effects of the classic MOR agonists, while reducing the rewarding properties and subsequent abuse liability as a result of D3R antagonism. This drug design may lead to the development of safer dual-target drugs, bridging the most promising pharmacological effects of two classes of molecules/targets previously developed independently. Of note, the drug design was to develop new small molecules endowed with differing ranges of affinities for both targets, independently modulating their physiology/pharmacology rather than towards simultaneous binding of MOR and D3R when in close proximity or in a heteromeric conformation. Nevertheless, if MOR-D3R heteromers are demonstrated to exist and are physiologically relevant, these molecules may be interesting tools to probe their pharmacology. Potent dual-target MOR agonist-D3R antagonist/partial agonist leads, based on different structural templates and scaffolds, presenting similar sub-micromolar to low nanomolar/sub-nanomolar affinities for their targets of interest were developed after extensive structure-activity relationship studies, computationally aided drug-design, and in vitro functional assays. These dual-target compounds have the pharmacological potential of maintaining the analgesic effects of MOR agonism, combined with the reduced opioid-abuse liability consequence of D3R antagonism.
These dual-target compounds provide innovative and non-addictive pain management treatments for pain (e.g., acute and/or chronic pain). These compounds also provide for the development of pharmacological tools to study alternative receptor targets, different from opioid receptors, for reducing addiction liability of commonly prescribed analgesics; including development of pharmacological tools to study brain plasticity, physiology, and receptor cross-modulation pharmacology, in pain and addiction.
These compounds as dual target pain management drugs provide safer pain management to subjects by bridging the most promising pharmacological effects of two classes of independent targets.
The general structure of the dual-target compounds involve a MOR Pharmacophore- Linker-D3R Pharmacophore where the MOR Pharmacophore provides agonism or partial agonism at MOR to provide an analgesic effect. The D3R Pharmacophore provides antagonism or partial agonism at D3R for reducing addictive liability. The dual-target compounds include those according to general Formula (I) and all sub-Formulas (IA), (IB), (IC), and (ID) as described herein.
A dual -target compound of Formula (I):
Figure imgf000014_0001
or a pharmaceutically acceptable salt thereof, wherein
Rx is CN or -(C=O)-N(Rz)2 wherein each instance of Rz independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, or C2-C6 alkanoyl; each instance of Ra independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; each instance of n independently is 0, 1, 2, or 3, specifically 0, 1, or 2, and more specifically 0 or 1 ;
Y1 is -NH- or a piperazinyl group attached to the core structure and L1 through the nitrogen atoms, specifically wherein when Y1 is piperazinyl group and L1-Y2-L2 is a covalent bond so that Y1Ar1;
L1 is a covalent bond or a linking group;
Y2 is a covalent bond or a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms, specifically a pyrrolidinyl or piperazinyl group;
L2 is a covalent bond or a linking group; and Ar1 is an aryl or a heteroaryl, wherein when Ar1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents, specifically Ar1 is substituted phenyl or optionally substituted pyridyl.
Within Formula (I) L1 can be a covalent bond or a linking group, wherein the L1 linking group is an alkyl chain containing 1, 2, 3, 4, 5, 6, 7, 8, 9 or more carbon atoms in the chain (the number of carbon atoms excluding pendant substitution), optionally including internal unsaturation, optionally an internal cycloalky group, optionally an internal heteroatom (e.g. O, N, S, or P, specifically an internal O (ether group) such as where L1 is - (CH2)y- O-(CH2)y- where each y independently is 1, 2, 3, or more), optionally a substitution on the alkyl chain where the substitution is described herein (e.g. oxo), or a combination thereof; and optionally wherein L1 is linked to Y2 via a heteroatom (e.g., O). Exemplary internal unsaturation includes a -CH=CH- group or a -C≡C- group. Exemplary internal cycloalkyl groups include cyclopropyl or cyclobutyl. Specific examples of L1 include - (CH2)g- wherein g is 2, 3, 4, 5, 6, 7, or 8 (e.g., n -butyl, n -pentyl, etc.); -(CH2)f-CH=CH- (CH2)f- wherein each instance of f independently is 1, 2, or 3 (e.g., E-butenyl); or
Figure imgf000015_0001
wherein each instance of f independently is 1, 2, or 3 (e.g., cis- (methyl)cyclopropyl-methyl, trans-(methyl)cyclopropyl-methyl, trans-(methyl)cyclopropyl- ethyl, trans-(ethyl)cyclopropyl-methyl), cis-(methyl)cyclopropyl-ethyl, cis- (ethyl)cyclopropyl-methyl) .
Within Formula (I) Y2 can be a covalent bond or a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms, specifically a pyrrolidinyl or piperazinyl group.
Within Formula (I) L2 can be a covalent bond or a linking group, wherein the L2 linking group is an alkyl chain containing 1, 2, 3, 4, 5, 6, 7, 8, 9 or more carbon atoms in the chain (the number of carbon atoms excluding pendant substitution), wherein the alkyl chain is linked to Ar1 through a covalent bond, O, S, NRy, -(C=O)-, C(RW)2, N(Ry)-(C=O)-, -(C=O)- N(Ry), -O-(C=O)-O-, -O-(C=O)-N(Ry)-, -N(Ry)-(C=O)-O-, or -N(Ry)-(C=O)-N(Ry)-; each instance of Ry independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, or C2-C6 alkanoyl; and each instance of Rw independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino.
Ar1 is an aryl or a heteroaryl, wherein when Ar1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents, specifically Ar1 is substituted phenyl or optionally substituted pyridyl. In specific embodiments, Ar1 is optionally substituted pyridyl, specifically pyridyl substituted with trifluoromethyl. In an embodiment, Ar1 is
Figure imgf000016_0002
wherein a is 1 or 2, and each instance of R1, R2, R3, and R4 independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy, hydroxyl, or halogen with the proviso that at least two of R1, R2, R3, and R4 are other than hydrogen (i.e., the phenyl comprises at least two substituents). In an embodiment, R1 and R4 are hydrogen, R2 and R3 are halogen, specifically Cl. In an embodiment, R1 and R4 are hydrogen, R2 is halogen, specifically Cl, and R3 is C1-C6 alkyl, specifically ethyl. In an embodiment, R1 is hydrogen or hydroxyl; R2is C1-C3 alkoxy, specifically -OMe; R3 is halogen, specifically Cl, and R4is C1-C6 alkyl, specifically ethyl. In an embodiment, R5 is trifluoromethyl. In an embodiment, R6 is ethyl and a is 1.
Dual-target compounds within the general Formula (I) include compounds according to Formulas (IA), (IB), (IC), (ID):
Figure imgf000016_0001
Formula (IC),
Figure imgf000017_0001
or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I); each instance of Rb independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino;
Z is N or CH; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH; each instance of Rc and Rd independently is hydrogen, hydroxyl, or halogen, specifically F; m is 0, 1, 2, 3, or 4, specifically m is 1 or 2; t is 0, 1, 2, 3, or 4, specifically t is 1 or 2; is a single bond, a double bond, a C3-C6 cycloalkyl, or a C3-C6 cycloalkenyl, specifically a single bond; and x is 1 or 2, specifically 1. When Z is CH, it is understood that the carbon can be optionally substituted such that the hydrogen is replaced with a substituent as defined herein as suitable for substitution on A1.
In an embodiment, there is provided a compound of formula X:
Figure imgf000017_0002
wherein Raand Rx have the meanings set out above;
Re is -C(O)NHRf; or a C1 to C4 alkyl group substituted by
Figure imgf000018_0001
wherein Ar1 has the meaning set out above;
Rs is H or CH3; and
Rt is H or OH;
Rf is a C1 to C4 alkyl group substituted by wherein Ar1 has the meaning set out above;
Figure imgf000018_0002
h is 1 or 2; Rt is H or OH; or a salt thereof.
In an embodiment, Rs is H. In an embodiment, R1 is OH In an embodiment, H is 1 In an embodiment H is 2
In an embodiment there is provided a compound of formula XI
Figure imgf000018_0003
wherein Ra, Rf, Rx, and n are defined above; or a salt thereof.
In an embodiment, there is provided a compound of formula CP
Figure imgf000019_0001
or a salt thereof.
The compounds are described using standard nomenclature. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this disclosure belongs. Unless clearly contraindicated by the context each compound name includes the free acid or free base form of the compound as well hydrates of the compound and all pharmaceutically acceptable salts of the compound. Formula (I) includes all subformulas thereof including Formulas (IA), (IB), (IC), and
(ID). The term “Formula (I)”, “Formula (IA)”, “Formula (IB)”, “Formula (IC)”, and “Formula (ID)” as used herein, encompasses all compounds that satisfy the formula, including any enantiomers, racemates and stereoisomers, as well as all pharmaceutically acceptable salts and radioisotopes of such compounds. The phrase “a compound of Formula (I)”, etc., includes all subgeneric groups of Formula (I), and so forth, as well as all forms of such compounds, including salts and hydrates, unless clearly contraindicated by the context in which this phrase is used.
In certain situations, the dual-target compounds may contain one or more asymmetric elements such as stereogenic centers, stereogenic axes and the like, e.g., asymmetric carbon atoms, so that the compounds can exist in different stereoisomeric forms. These compounds can be, for example, racemates or optically active forms. For compounds with two or more asymmetric elements, these compounds can additionally be mixtures of diastereomers. For compounds having asymmetric centers, it should be understood that all of the optical isomers and mixtures thereof are encompassed. In these situations, single enantiomers, i.e., optically active forms, can be obtained by asymmetric synthesis, synthesis from optically pure precursors, or by resolution of the racemates. Resolution of the racemates can also be accomplished, for example, by conventional methods such as crystallization in the presence of a resolving agent, or chromatography, using, for example, a chiral high-performance liquid chromatography (HPLC) column. Where a compound exists in various tautomeric forms, the compound is not limited to any one of the specific tautomers, but rather includes all tautomeric forms.
All isotopes of atoms occurring in the present compounds are contemplated. Isotopes include those atoms having the same atomic number but different mass numbers. By way of general example, and without limitation, isotopes of hydrogen include tritium and deuterium; isotopes of carbon include 11C, 13C, and 14C; and an isotope of fluorine includes 18F.
The term “active agent”, as used herein, means a dual-target compound of the disclosed Formulas that when administered to a patient, alone or in combination with another compound, element, or mixture, confers, directly or indirectly, a physiological effect on the patient. The indirect physiological effect may occur via a metabolite or other indirect mechanism. When the active agent is a compound, then salts, solvates (including hydrates) of the free compound, crystalline forms, non-crystalline forms, and any polymorphs of the compound are included. All forms are contemplated herein regardless of the methods used to obtain them.
A dash ("-") that is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, -(CH2)C3-C8 cycloalkyl is attached through carbon of the methylene (CH2) group.
“Alkanoyl” is an alkyl group as defined herein, covalently bound to the group it substitutes by a keto (-(C=O)-) bridge. Alkanoyl groups have the indicated number of carbon atoms, with the carbon of the keto group being included in the numbered carbon atoms. For example a C2 alkanoyl group is an acetyl group having the formula CH3(C=O)-.
The term “alkyl”, as used herein, means a branched or straight chain saturated aliphatic hydrocarbon group having the specified number of carbon atoms, generally from 1 to about 12 carbon atoms. The term C1-C6 alkyl as used herein indicates an alkyl group having from 1, 2, 3, 4, 5, or 6 carbon atoms. Other embodiments include alkyl groups having from 1 to 8 carbon atoms, 1 to 4 carbon atoms or 1 or 2 carbon atoms, e.g. C1-C6 alkyl, C1-C4 alkyl, and C1-C2 alkyl. When C0-Cn alkyl is used herein in conjunction with another group, for example, (cycloalkyl)C0-C4 alkyl, the indicated group, in this case cycloalkyl, is either directly bound by a single covalent bond (C0), or attached by an alkyl chain having the specified number of carbon atoms, in this case 1, 2, 3, or 4 carbon atoms. Examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, 3-methylbutyl, t- butyl, n-pentyl, and sec -pentyl.
The term “alkoxy” represents an alkyl group as defined above with the indicated number of carbon atoms attached through an oxygen bridge. Examples of alkoxy include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, 2-butoxy, t-butoxy, n-pentoxy, 2-pentoxy, 3-pentoxy, isopentoxy, neopentoxy, n-hexoxy, 2-hexoxy, 3-hexoxy, and 3-methylpentoxy.
The term “aryl”, as used herein, means aromatic groups containing only carbon in the aromatic ring or rings. Typical aryl groups contain 1 to 3 separate, fused, or pendant rings and from 6 to about 18 ring atoms, without heteroatoms as ring members. When indicated, such aryl groups may be further substituted with carbon or non-carbon atoms or groups. Bicyclic aryl groups may be further substituted with carbon or non-carbon atoms or groups. Bicyclic aryl groups may contain two fused aromatic rings (naphthyl) or an aromatic ring fused to a 5- to 7-membered non-aromatic cyclic group that optionally contains 1 or 2 heteroatoms independently chosen from N, O, and S, for example, a 3,4-methylenedioxy- phenyl group (e.g., a benzo[d] [1,3]dioxole). Aryl groups include, for example, phenyl, naphthyl, including 1 -naphthyl and 2-naphthyl, and bi-phenyl.
The term “cycloalkyl”, as used herein, indicates a saturated hydrocarbon ring group, having only carbon ring atoms and having the specified number of carbon atoms, usually from 3 to about 8 ring carbon atoms, or from 3 to about 7 carbon atoms. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl as well as bridged or caged saturated ring groups such as norborane or adamantane.
The term “cycloalkenyl”, as used herein, means a saturated hydrocarbon ring group, comprising one or more unsaturated carbon-carbon bonds, which may occur in any stable point of the ring, and having the specified number of carbon atoms. Monocyclic cycloalkenyl groups typically have from 3 to about 8 carbon ring atoms or from 3 to 7 (3, 4, 5, 6, or 7) carbon ring atoms. Cycloalkenyl substituents may be pendant from a substituted nitrogen or carbon atom, or a substituted carbon atom that may have two substituents may have a cycloalkenyl group, which is attached as a spiro group. Examples of cycloalkenyl groups include cyclopropenyl, cyclobutenyl, cyclopentenyl, or cyclohexenyl as well as bridged or caged saturated ring groups such as norbornene.
The term “heteroaryl”, as used herein, indicates a stable 5- to 7-membered monocyclic or 7- to 10-membered bicyclic heterocyclic ring which contains at least 1 aromatic ring that contains from 1 to 4, or specifically from 1 to 3, heteroatoms chosen from N, O, and S, with remaining ring atoms being carbon. When the total number of S and O atoms in the heteroaryl group exceeds 1, these heteroatoms are not adjacent to one another. Specifically, the total number of S and O atoms in the heteroaryl group is not more than 2, more specifically the total number of S and O atoms in the heteroaryl group is not more than 1. A nitrogen atom in a heteroaryl group may optionally be quaternized. When indicated, such heteroaryl groups may be further substituted with carbon or non-carbon atoms or groups. Such substitution may include fusion to a 5 to 7-membered saturated cyclic group that optionally contains 1 or 2 heteroatoms independently chosen from N, O, and S, to form, for example, a [1,3]dioxolo[4,5-c]pyridyl group. In certain embodiments 5- to 6-membered heteroaryl groups are used. Examples of heteroaryl groups include, but are not limited to, pyridyl, indolyl, pyrimidinyl, pyridizinyl, pyrazinyl, imidazolyl, oxazolyl, furanyl, thiophenyl, thiazolyl, triazolyl, tetrazolyl, isoxazolyl, quinolinyl, pyrrolyl, pyrazolyl, benz[b]thiophenyl, isoquinolinyl, quinazolinyl, quinoxalinyl, thienyl, isoindolyl, and 5, 6,7,8- tetrahydroisoquinoline.
“Haloalkyl” includes both branched and straight-chain alkyl groups having the specified number of carbon atoms, substituted with 1 or more halogen atoms, up to the maximum allowable number of halogen atoms. Examples of haloalkyl include, but are not limited to, trifluoromethyl, difluoromethyl, 2-fluoroethyl, and penta-fluoroethyl.
“Haloalkoxy” is a haloalkyl group as defined herein attached through an oxygen bridge (oxygen of an alcohol radical).
“Halo” or “halogen” is any of fluoro, chloro, bromo, and iodo.
“Mono- and / or di-alkylamino” is a secondary or tertiary alkyl amino group, wherein the alkyl groups are independently chosen alkyl groups, as defined herein, having the indicated number of carbon atoms. The point of attachment of the alkylamino group is on the nitrogen. Examples of mono- and di-alkylamino groups include ethylamino, dimethylamino, and methyl-propyl- amino.
The term “substituted”, as used herein, means that any one or more hydrogens on the designated atom or group is replaced with a selection from the indicated group, provided that the designated atom’s normal valence is not exceeded. When the substituent is oxo (i.e., =O) then 2 hydrogens on the atom are replaced. When an oxo group substitutes aromatic moieties, the corresponding partially unsaturated ring replaces the aromatic ring. For example, a pyridyl group substituted by oxo is a pyridone. A stable compound or stable structure is meant to imply a compound that is sufficiently robust to survive isolation from a reaction mixture, and subsequent formulation into an effective therapeutic agent.
Unless otherwise specified substituents are named into the core structure. For example, it is to be understood that when (cycloalkyl)alkyl is listed as a possible substituent the point of attachment of this substituent to the core structure is in the alkyl portion, or when arylalkyl is listed as a possible substituent the point attachment to the core structure is the alkyl portion.
Suitable groups that may be present on a “substituted” or “optionally substituted” position include, but are not limited to, halogen; cyano; hydroxyl; nitro; azido; alkanoyl (such as a C2-C6 alkanoyl group such as acyl or the like); carboxamido; alkyl groups (including cycloalkyl groups) having 1 to about 8 carbon atoms, or 1 to about 6 carbon atoms; alkenyl and alkynyl groups including groups having one or more unsaturated linkages and from 2 to about 8, or 2 to about 6 carbon atoms; alkoxy groups having one or more oxygen linkages and from 1 to about 8, or from 1 to about 6 carbon atoms; aryloxy such as phenoxy; alkylthio groups including those having one or more thioether linkages and from 1 to about 8 carbon atoms, or from 1 to about 6 carbon atoms; alkylsulfinyl groups including those having one or more sulfinyl linkages and from 1 to about 8 carbon atoms, or from 1 to about 6 carbon atoms; alkylsulfonyl groups including those having one or more sulfonyl linkages and from 1 to about 8 carbon atoms, or from 1 to about 6 carbon atoms; aminoalkyl groups including groups having one or more N atoms and from 1 to about 8, or from 1 to about 6 carbon atoms; aryl having 6 or more carbons and one or more rings, (e.g., phenyl, biphenyl, naphthyl, or the like, each ring either substituted or unsubstituted aromatic); arylalkyl having 1 to 3 separate or fused rings and from 6 to about 18 ring carbon atoms, with benzyl being an exemplary arylalkyl group; arylalkoxy having 1 to 3 separate or fused rings and from 6 to about 18 ring carbon atoms, with benzyloxy being an exemplary arylalkoxy group; or a saturated, unsaturated, or aromatic heterocyclic group having 1 to 3 separate or fused rings with 3 to about 8 members per ring and one or more N, O or S atoms, e.g. coumarinyl, quinolinyl, isoquinolinyl, quinazolinyl, pyridyl, pyrazinyl, pyrimidinyl, furanyl, pyrrolyl, thienyl, thiazolyl, triazinyl, oxazolyl, isoxazolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzothiazolyl, tetrahydrofuranyl, tetrahydropyranyl, piperidinyl, morpholinyl, piperazinyl, and pyrrolidinyl. Such heterocyclic groups may be further substituted, e.g. with hydroxy, alkyl, alkoxy, halogen and amino.
The term “dosage form”, as used herein, means a unit of administration of an active agent. Examples of dosage forms include tablets, capsules, injections, suspensions, liquids, emulsions, creams, ointments, suppositories, inhalable forms, transdermal forms, and the like. An exemplary dosage form is a solid oral dosage form.
The term “pharmaceutical compositions”, as used herein, are compositions comprising at least one active agent, such as a dual-target compound or pharmaceutically acceptable salt thereof and at least one other substance, such as a carrier. Pharmaceutical compositions meet the U.S. FDA’s GMP (good manufacturing practice) standards for human or non-human drugs. The pharmaceutical compositions can be formulated into a dosage form.
The term “pharmaceutically acceptable salt”, as used herein, includes derivatives of the disclosed compounds in which the parent compound is modified by making inorganic and organic, acid or base addition salts thereof. The salts of the present compounds can be synthesized from a parent compound that contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting free acid forms of these compounds with a stoichiometric amount of the appropriate base (such as Na, Ca, Mg, or K hydroxide, carbonate, bicarbonate, or the like), or by reacting free base forms of these compounds with a stoichiometric amount of the appropriate acid. Such reactions are typically carried out in water or in an organic solvent, or in a mixture of the two. Generally, non-aqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are used, where practicable. Salts of the present compounds further include solvates of the compounds and of the compound salts.
Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. The pharmaceutically acceptable salts include the conventional non-toxic salts and the quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. For example, conventional non-toxic acid salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, mesylic, esylic, besylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, HOOC-(CH2)n-COOH where n is 0-4, and the like. Lists of additional suitable salts may be found, e.g., in Remington’s Pharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton, Pa., p. 1418 (1985).
In an embodiment, a pharmaceutical composition comprises a dual-target compound or a pharmaceutically acceptable salt thereof and optionally further comprising a pharmaceutically acceptable carrier.
The term “carrier”, as used herein, applied to pharmaceutical compositions refers to a diluent, excipient, or vehicle with which an active compound is provided.
The compounds can be administered as the neat chemical or administered as a pharmaceutical composition. Accordingly, an embodiment provides pharmaceutical compositions comprising a dual-target compound or pharmaceutically acceptable salt thereof, together with a pharmaceutically acceptable carrier.
The dual-target compound may be administered orally, topically, parenterally, by inhalation or spray, sublingually, transdermally, via buccal administration, rectally, as an ophthalmic solution, or by other means, in dosage unit formulations containing conventional pharmaceutically acceptable carriers. The pharmaceutical composition may be formulated as any pharmaceutically useful form, e.g., as an aerosol, a cream, a gel, a pill, a capsule, a tablet, a syrup, a transdermal patch, a subcutaneous formulation, or an ophthalmic solution. Some dosage forms, such as tablets and capsules, can be subdivided into suitably sized unit doses containing appropriate quantities of the active components, e.g., an effective amount to achieve the desired purpose.
Carriers include excipients and diluents and must be of sufficiently high purity and sufficiently low toxicity to render them suitable for administration to the patient being treated. The carrier can be inert or it can possess pharmaceutical benefits of its own. The amount of carrier employed in conjunction with the compound is sufficient to provide a practical quantity of material for administration per unit dose of the compound.
Classes of carriers include, for example, buffering agents, coloring agents, diluents, disintegrants, emulsifiers, flavorants, glidants, lubricants, preservatives, stabilizers, surfactants, tableting agents, and wetting agents. Some carriers may be listed in more than one class, for example vegetable oil may be used as a lubricant in some formulations and a diluent in others. Exemplary pharmaceutically acceptable carriers include sugars, starches, celluloses, powdered tragacanth, malt, gelatin, talc, and vegetable oils.
The pharmaceutical compositions can be formulated for oral administration. These compositions can contain between 0.1 and 99 weight percent (“wt.%”) of a dual-target compound or pharmaceutically acceptable salt thereof, and usually at least about 5 wt.%. Some embodiments contain from about 25 wt.% to about 50 wt. % or from about 5 wt.% to about 75 wt.% of a compound of a dual-target compound.
The dual-target compound may be administered to the patient as a daily dosage regimen in unit dosage form one, two, three, or more times daily, specifically once daily.
Unit dosage forms for oral administration can contain about 0.5 mg to about 500 mg, specifically about 1 mg to about 400 mg, more specifically about 3 mg to about 200 mg, and yet more specifically about 5 mg to about 100 mg of the dual-target compound. Unit dosage amounts for parenteral administration can contain about 0.1 mg to about 200 mg, specifically about 1 mg to about 100 mg, and more specifically about 2 to about 50 mg of the dual-target compound.
The dual-target compound can be administered to the patient for a period of time for acute therapy or for continuous therapy, for example one or more weeks, two or more weeks, three or more weeks, a month, two or more months, and the like.
The pharmaceutical composition can be formulated in a package or kit comprising the pharmaceutical composition containing a dual-target compound or a pharmaceutically acceptable salt thereof in a container and further comprising instructions for using the composition in order to elicit a therapeutic effect in a patient.
The pharmaceutical composition can also be formulated in a package or kit comprising the pharmaceutical composition of a dual-target compound or pharmaceutically acceptable salt thereof in a container and further comprising instructions for using the composition to treat a patient suffering from pain, including e.g., a dosing regimen.
In an embodiment, a method for treating pain or eliciting an analgesic effect comprises providing an effective amount of a dual-target compound or pharmaceutically acceptable salt thereof to a patient in need of such treatment. Within this embodiment, the dual-target compound or pharmaceutically acceptable salt thereof is provided in the form of a pharmaceutical composition.
The dual-target compounds provide safer non-addictive treatments for effective pain management. The therapeutically effective amount of dual-target compounds may be lower than amounts of conventional opioids as the dopamine D3 antagonist/partial agonist effect will potentiate the mu-opioid analgesic effect and possibly will prevent dose escalation for pain relief. The selective dopamine D3 receptor antagonist/partial agonist effect may mitigate the development of opioid addiction by eliminating the need for dose escalation and prevent the development of dependence and misuse.
The term “patient”, as used herein, is a human in need of medical treatment. Medical treatment can include treatment of an existing condition, such as a disease or disorder, prophylactic or preventative treatment, or diagnostic treatment.
The term “providing”, as used herein, means giving, administering, selling, distributing, transferring (for profit or not), manufacturing, compounding, or dispensing.
The terms “treating” and “treatment”, as used herein, includes providing a therapeutically effective amount of a dual-target compound sufficient to prevent or inhibit or relieve pain; to provide analgesia.
The term “therapeutically effective amount” as used herein, means an amount effective, when administered to a patient, to provide a therapeutic benefit, such as an amelioration of symptoms, e.g., to treat a patient suffering from pain, to provide analgesia, to mitigate the development of opioid addiction, and the like.
As used herein the pain to be treated by the methods is not particularly limiting and can include chronic pain, acute pain, breakthrough pain, post-operative pain, perioperative pain, mild pain, moderate pain, severe pain, bone and joint pain, soft tissue pain, nerve pain, pain due to a disease or disorder, pain due to trauma, neuropathic pain, nociceptive pain, radicular pain, and the like, and a combination thereof. The compounds described herein have the advantage that they will have lower addictive liability compared to opioid agonists.
This invention is further illustrated by the following examples that should not be construed as limiting.
EXAMPLES
ABBREVIATIONS
DA (dopamine); D2-likeR (dopamine D2-likereceptors); OUD (opioid use disorders); CADD (computer aided drug design); BRET (bioluminescence resonance energy transfer); HEK 293 cells (human embryonic kidney 293 cells); HPLC (high performance liquid chromatography); HRMS (high resolution mass spectrometry); DMA (dichloromethane, methanol, ammonium hydroxide); EDC (1-Ethy1-3-(3-dimethylaminopropyl)carbodiimide); HOBt (hydroxybenzotriazole); HCTU (O-(1H-6-Chlorobenzotriazole-1-yl)-1,1,3,3- tetramethyluroniumhexafluorophosphate); DIPEA (N,N-diisopropylethylamine); STAB (sodium triacetoxyborohydride); DMP (dess-martin periodinane); ACN (acetonitrile); LAH (lithium aluminium hydride); GPA (G-protein Activation); mp (melting point); TBME (tert- butyl methyl ether); AcOH (acetic acid); DCE (1,2-Dichloroethane).
Example 1. Compound Design and Compound Synthesis
Several well-known MOR agonists, such as loperamide (3) (peripherally limited potent MOR agonist, FDA approved for anti-diarrhea treatment), and diphenoxylate (4), share similar structural motifs with the highly potent non-selective D2R/D3R antagonist haloperidol (5) (FIG. 1). A substituted phenyl-piperazine and/or phenyl-piperidine synthon that was common to both classes of ligands was identified and modified to generate small molecules exploiting the structural similarities between MOR and D3R proteins, thus achieving dual-target binding. Methadone (6), (FIG. 1), also showed low micromolar D2R and D3R affinity in the binding assays (Table 1), supporting the hypothesis that some of its structural fragments, could be used to target not only the MOR orthosteric binding site (OBS), but the D2R and D3R as well. Unlike 6, the synthetic opioid fentanyl, with its completely different structural features, showed an interesting moderate affinity for the dopamine D4R subtype, but total lack of recognition for either D2R or D3R (Table 1).
A fragment-based drug design approach, supported by molecular docking, computer- aided drug design (CADD), and extensive in-vitro pharmacology was used to guide Structure- Activity Relationships (SAR), hit optimization, and lead identification. Bivalent dual-target analogs are those compounds where a MOR agonist primary pharmacophore (PP) is tethered with a D3R antagonist PP; both can bind their respective OBS, eliciting their corresponding opioid agonist and dopaminergic antagonist effects. Consistent with the definition of bitopic ligands (Newman et al., A., 2016 Philip S. Portoghese Medicinal Chemistry Lectureship: Designing Bivalent or Bitopic Molecules for G-Protein Coupled Receptors. The Whole Is Greater Than the Sum of Its Parts. J Med Chem 2020, 63 (5), 1779-1797), these new analogs are classified as bitopic when they incorporate a MOR agonist PP, targeting its corresponding OBS that also has structural features suitable for D3R OBS recognition, tethered to a D3R secondary pharmacophore (SP), identifying the D3R secondary binding pocket (SBP) Chien et al. “Structure of the human dopamine D3 receptor in complex with a D2/D3 selective antagonist” Science 2010, 330 (6007), 1091-5). Of note, this D3R SP may also elicit binding interactions within the MOR SBP. All new compounds presented designed linkers, as tethering fragments, with specific SAR focusing on the linkers’ regiochemistry, stereochemistry and substituents presentation (Newman et al. 2020). All newly synthesized analogs were tested for their on-target and off-target affinities at MOR, D2R, D3R, and D4R, in a combination of agonist and antagonist radioligand competition binding assays. Compounds selected as hits, for their promising dual-target and sub-micromolar affinities, were further evaluated in functional bioluminescence resonance energy transfer (BRET) studies, to assess their agonist and/or antagonist potencies for the target of interest, and possible functional selectivity (biased agonism) for specific signaling pathways.
The novel class of dual-target compounds can be subdivided, as depicted in FIG. 1 (A-B), in three general templates: A) the N,N-dimethy 1-2,2-diphenyl acetamide, 2,2- diphenylacetonitrile, and 1,1-diphenylbutan-2-one MOR PPs, derived from loperamide (3), diphenoxylate (4), and methadone (6) respectively (FIG. 1), were tethered with suitably substituted PPs, inspired by selective and non-selective D3R antagonists (e.g., 1, 2, PG648 (7), eticlopride (8) and SB269,652 (9); FIG. 1), via short ethyl linker chain; and B) the same MOR OBS-binding agonist PPs were linked with D3R OBS antagonist PPs via a longer and more complex butyl linker, substituted with a 3-hydroxyl group, or the piperazine or pyrrolidine basic function in several regiochemical combinations.
The first series of compounds with the 2,2-diphenylbutanenitrile as the MOR PP, inspired by 4, were prepared as depicted in Scheme 1. Starting from the commercially available 4-bromo-2,2-diphenylbutanenitrile, simple N -alkylation under basic conditions yielded the first group of bivalent MOR-D3R hybrids, where the D3R PP was represented by 2-phenylethan-1-amine (12), 1-(2,3-dichlorophenyl)piperazine (13), 4-(4-(2,3- dichlorophenyl)piperazin-1-yl)butan-1-amine (14), and 4-amino-1-(4-(2,3- dichlorophenyl)piperazin-1-yl)butan-2-ol (15). This provided initial SAR deduction, by increasing the structural complexity of the D3R PP, and simultaneously modifying the linker length and substitution. To investigate the optimal regiochemistry for introducing the linker and D3R PP, compound 18 was prepared, where the butyl-4-(2,3-dichlorophenyl)piperazine synthon was introduced to replace the nitrile, while maintaining the MOR 4- (dimethylamino)-2,2-diphenylbutananiide moiety, as seen in both 3 and 6 (FIG. 1). In detail, 4-bromo-2,2-diphenylbutanenitrile was first N-alkylated with dimethylamine hydrochloride (Me2NH·HCl) under basic conditions, followed by hydrolysis of the nitrile in the presence of 48% HBr (aq solution) to yield the HBr salt of amino acid 17. Subsequent amidation mediated by EDC, HOBt, and 4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butan-1-amine yielded the desired product 18. Despite the importance of the alpha-methyl group of 6 being well reported in the literature (Goldberg et al. “Stereochemical basis for a unified structure activity theory of aromatic and heterocyclic rings in selected opioids and opioid peptides” Perspect Medicin Chem 2010, 4, 1-10), favoring the optimal binding pose within the MOR OBS, it was decided to study SAR of structurally simplified analogs. Thus, via simple Grignard addition to the nitrile 16, the desmethyl-methadone 19 was prepared.
Figure imgf000030_0001
Scheme 1. a) appropriate primary or secondary amine, K2CO3, acetonitrile (ACN), D; b) Me2NH HCl, K2CO3, ACN, Δ; c) HBr 48% in H2O, Δ; d) N-(3-dimethylaminopropyl)-N- ethylcarbodiimide hydrochloride (EDC), 1-hydroxybenzotriazole hydrate (HOBt), 4-(4-(2,3- dichlorophenyl)piperazin- 1-yl)butan- 1-amine, N,N-diisopropylethylamine (Hiinig’ s base, DIPEA), dichloromethane (DCM); e) ethyl magnesium bromide (EtMgBr) 3M in diethyl ether (Et2O), toluene, Δ.
In Scheme 2, in order to investigate the structural requirement of the D3R pharmacophore, and in particular the effect of replacing the basic butyl-4-(2,3- dichlorophenyl)piperazine, with the corresponding amide analog, HCTU mediated amide coupling of 5-((tert-buloxycarbonyl)amino)pentanoic acid, followed by removal of the Boc- protecting group, and consequent mono N-alkylation with 4-bromo-2,2-diphenylbutanenitrile afforded the desired product, 21. The longer 5 carbon atom linker, instead of the canonical butyl chain, was chosen because of the increased rigidity of the amide function and need for extending the tethered PP to an optimal distance.
Figure imgf000031_0001
Scheme 2. a) 1-(2,3-dichlorophenyl)piperazine, 2-(6-chloro-1-H-benzotriazole-1-yl)-1, 1,3,3- tetramethylaminium hexafluorophosphate (HCTU), DCM; b) trifluoroacetic acid (TFA), DCM; c) 4-bromo-2,2-diphenylbutanenitrile, K2CO3, ACN, Δ.
The switch from 2,2-diphenylbutanenitrile (4-like analogs) to N,N-dimethyl-2,2- diphenylbutanamide (3-like analogs) as the MOR PP was achieved as described in Scheme 3. Starting from the commercially available N-(3,3-diphenyldihydrofuran-2(3H)-ylidene)-N - methylmethanaminium bromide, simple ring opening with the appropriate primary or secondary amines afforded compounds 22, presenting the 6-like dimethylamino function, 23, where the 2,3-dichlorophenyl piperazine D3R scaffold was introduced, as well as 24, whose
1,2,3,4-tetrahydroisoquinoline-7-carbonitrile is another common D2R-D3R antagonist PP fragment, present in well-characterized ligands, such as 9 (Kumar et al. “Synthesis and Pharmacological Characterization of Novel trans-Cyclopropylmethyl-Linked Bivalent Ligands That Exhibit Selectivity and Allosteric Pharmacology at the Dopamine D3 Receptor (D3R)” J Med Chem 2017, 60 (4), 1478-1494; Kopinathan et al. “Subtle Modifications to the Indole-2-carboxamide Motif of the Negative Allosteric Modulator N-(( trans)-4-(2-(7-Cyano-
3,4-dihydroisoquinolin-2(1H)-yl)ethyl)cyclohexyl)-1H-indole-2-carboxamide (SB269652) Yield Dramatic Changes in Pharmacological Activity at the Dopamine D2 Receptor” J Med Chem 2019, 62 (1), 371-377; Draper-Joyce et al. “The action of a negative allosteric modulator at the dopamine D2 receptor is dependent upon sodium ions” Sci Rep 2018, 8 (1), 1208; Verma et al. “The E2.65A mutation disrupts dynamic binding poses of SB269652 at the dopamine D2 and D3 receptors” PLoS Comput Biol 2018, 14 (1), el005948). To investigate the effect of the linker length and substitution on the bivalent hybrid analogs, N-(3,3-diphenyldihydrofuran-2(3H)-ylidene)-N-methylmethanaminium bromide was simply washed with 2N NaOH in H2O, and extracted with DCM, to obtain the alcohol intermediate 25, which was then oxidized to the aldehyde using Dess-Martin periodinane and then mono-N-alkylated via reductive amination conditions with the appropriate primary and secondary amines. This small library of compounds (27, 28, 29, 30, 31, and 32) covered a large structural variety of canonical D3R antagonist PPs, as well as butyl and hydroxyl substituted linkers, known for increasing D3R subtype selectivity (Newman et al. “N-(4-(4- (2,3-dichloro- or 2-methoxyphenyl)piperazin-1-yl)butyl)heterobiarylcarboxamides with functionalized linking chains as high affinity and enantioselective D3 receptor antagonists” J Med Chem 2009, 52 (8), 2559-70.).
Figure imgf000032_0001
Scheme 3. a) appropriate secondary amine, K2CO3, ACN, tert-butyl methyl ether (TBME), Δ; b) 2N NaOH in H2O; c) Dess-Martin periodinane (DMP), DCM, 0 °C to RT; d) appropriate primary or secondary amine, catalytic acetic acid (cat. AcOH), sodium triacetoxyborohydride (STAB), 1,2-dichloroethane (DCE).
Compound 34, containing the 1,2,3,4-tetrahydroisoquinoline-7-carbonitrile pharmacophore was synthesized according to Scheme 4, via preparation of intermediate 33, and reductive amination with 26.
Figure imgf000033_0001
Scheme 4. a) N-(4-bromobutyl)phthalimide, K2CO3, cat. KI, ACN, Δ; b) hydrazine (NH2NH2), ethanol (EtOH), D; c) N,N-dimethyl-4-oxo-2,2-diphenylbutanamide (26), cat. AcOH, STAB, DCE.
In order to expand the library towards different D3R PP, the canonical piperazine and 1,2,3,4-tetrahydroisoquinoline, inspired by selective D3R antagonists and partial agonists (1, 2, 7, and 9; FIG. 1), were replaced in Scheme 5 with the highly decorated phenyl-N- (pyrrolidin-2-ylmethyl)benzamide derived from the eticlopride pharmacophore (8, FIG. 1). (S)-Nor-eticlopride (obtained from the NIDA Drug Supply Program) and simple alkylation with 4-bromo-2,2-diphenylbutanenitrile yielded compound 35, introducing the 2,2-diphenyl- nitrile MOR PP, tethered by an ethyl linker. Meanwhile, formation of intermediate 36, allowed the synthesis of analog 37, tethered via the longer butyl-amino linker.
Figure imgf000034_0001
Scheme 5. a) N-(4-bromobutyl)phthalimide, K2CO3, ACN, D; b) NH2NH2, EtOH, Δ; c) K2CO3, ACN, Δ. Analogous to the approach described above for the phenylpiperazine series, the replacement of the diphenyl nitrile MOR PP was investigated, with the 3-like N,N- dimethylamide functional group for the 8-based bivalent analogs. In Scheme 6, the substituted benzoic acid intermediate was prepared following previous literature procedures (Kumar et al. 2016; De Paulis et al. “Synthesis, crystal structure and anti-dopaminergic properties of eticlopride (FLB 131)” Eur. J. Med. Chem. 1985, 20 (3), 273-279). The benzoic acid was coupled with 2-(4-(2-(aminomethyl)pyrrolidin-1-yl)butyl)isoindoline-1,3-dione, which was freshly prepared in situ via selective Boc- deprotection of 38, prior to the HCTU mediated amide coupling. The phthalimide group in intermediate 39 was removed and the resulting primary amine was mono-N-alkylated via reductive amination to yield 40 as the racemic mixture.
In this case, it was decided to synthesize the racemic mixture, starting from the commercially available tert -butyl (pyrrolidin-2-ylmethyl)carbamate, because although 8 favors the (S) absolute configuration at the pyrrolidine ring, the possibility of different stereochemical requirements for this bivalent analog was not excluded, as seen in another series of bivalent/bitopic D3R ligands (Battiti et al. 2020).
Figure imgf000035_0001
Scheme 6. a) N-(4-bromobutyl)phthalimide, K2CO3, ACN, D; b) TFA, DCM; c) HCTU, DCM; d) NH2NH2, EtOH, Δ; e) cat. AcOH, STAB, DCE.
SAR for an alternative MOR PP, with a 3,3-diphenyl substituted pyrrolidine, were investigated through the synthesis of analogs in Scheme 7. The common starting material 4- bromo-2,2-diphenylbutanenitrile was reacted with lithium aluminum hydride (LAH), to give the primary amine, and consequent ring-closure in a one-pot step. Intermediate 41 was either readily methylated with methyl chloroformate and in situ LAH reduction (42) or reacted with propionyl chloride to yield the cyclic amide synthon 43. This rather simple PP allowed us to evaluate the effect of structural rigidity in 6- and 3-like MOR PP, and the effect of replacing the protonatable cyclic amine to a cyclic amide. To prepare the bivalent analog 46, 41 was initially alkylated with 2-chloroacetyl chloride, then with racemic tert-butyl (pyrrolidin-2- ylmethyl)carbamate, to yield 45. Finally, Boc- deprotection and amide coupling afforded the desired product.
As consistently observed in previous work (Newman et al. 2020), when generating bitopic or bivalent ligand SAR, it is necessary to study structural requirements not only for the PP and/or SP, but regiochemistry and stereochemistry of the linkers, which can play an important role in their biological activity.
Figure imgf000036_0001
Scheme 7. a) LAH, THF, 0 °C to RT; b) 2-chloroacetyl chloride, DIPEA, THF, 0 °C to RT; c) cat. KI, K2CO3, ACN, A; d) TFA, DCM; e) HCTU, DIPEA, DCM; f) methyl chloroformate, DIPEA, DCM, 0 °C to RT; g) LAH, THF, 0 °C to RT; h) propionyl chloride, DIPEA, DCM, from 0 °C to RT.
In Scheme 8, a modification of the regiochemistry for the pyrrolidine D3R PP scaffold was approached. The final compound 48 presents the MOR diphenyl-N,N-di methyl amide PP tethered to the D3R PP, via a butyl ether linker fused in postion-4 of the pyrrolidine nucleus, in a rel -trans stereochemistry configuration with respect to the 8 amide PP appended in position-2. The trans configuration has been proposed (Shaik, A. B. et al, unpublished data) to be the optimal stereochemistry to achieve high affinity for D3R. This was easily introduced as shown in Scheme 8, starting from 47 (Shaik, A. B. et al., unpublished data) via reductive amination and Boc-deprotection to ultimately yield 48.
Figure imgf000037_0001
Scheme 8. A) cat. AcOH, STAB, DCE; b) TFA, DCM.
All chemicals and solvents were purchased from chemical suppliers unless otherwise stated and used without further purification. All melting points were determined (when obtainable) on an OptiMelt automated melting point system and are uncorrected. The 1H and 13C NMR spectra were recorded on a Varian Mercury Plus 400 instrument. Proton chemical shifts are reported as parts per million (δ ppm) relative to tetramethylsilane (0.00 ppm) as an internal standard, or to deuterated solvents. Coupling constants are measured in Hz. Chemical shifts for 13C NMR spectra are reported as parts per million (δ ppm) relative to deuterated CHCl3 or deuterated MeOH (CDCI377.5 ppm, CD3OD 49.3 ppm). Chemical shifts, multiplicities and coupling constants (7) have been reported and calculated using Agilent- NMR 400Mr or MNova 9.0 software. Gas chromatography-mass spectrometry (GC/MS) data were acquired (where obtainable) using an Agilent Technologies (Santa Clara, CA) 7890B GC equipped with an HP-5MS column (cross-linked 5% PH ME siloxane, 30 m x 0.25 mm i.d. x 0.25 μm film thickness) and a 5977B mass-selective ion detector in electron-impact mode. Ultrapure grade helium was used as the carrier gas at a flow rate of 1.2 mL/min. The injection port and transfer line temperatures were 250 and 280 °C, respectively, and the oven temperature gradient used was as follows: the initial temperature (70 °C) was held for 1 min and then increased to 300 °C at 20 °C/min and maintained at 300 °C for 4 min, total run time 16.5 min. Column chromatography was performed using a Teledyne Isco CombiFlash RF flash chromatography system, or a Teledyne Isco EZ-Prep chromatography system. Preparative thin layer chromatography was performed on Analtech silica gel plates (1000 μm). When %DMA is reported as eluting system, it stands for % of methanol in DCM, in presence of 0.5%-1% NH4OH. Preparative chiral HPLC was performed using a Teledyne Isco EZ-Prep chromatography system with DAD (Diode Array Detector) and ELS detectors. HPLC analysis was performed using an Agilent Technologies 1260 Infinity system coupled with DAD (Diode Array Detector). For each analytical HPLC run multiple DAD λ absorbance signals were measured in the range of 210-280 nm. Separation of the analyte, purity and enantiomeric/diastereomeric excess determinations were achieved at 40 °C using the methods reported in each detailed reaction description. Preparative and analytical HPLC columns were purchased from Daicel corporation or Phenomenex. HPLC methods and conditions are reported in the descriptions of the chemical reactions where they were applied. Microanalyses were performed by Atlantic Microlab, Inc. (Norcross, GA) and agree with ± 0.4% of calculated values. HRMS (mass error within 5 ppm) and MS/MS fragmentation analysis were performed on a LTQ-Orbitrap Velos (Thermo-Scientific, San Jose, CA) coupled with an ESI source in positive ion mode to confirm the assigned structures and regiochemistry. Unless otherwise stated, all the test compounds were evaluated to be >95% pure on the basis of combustion analysis, NMR, GC-MS, and HPLC-DAD. The detailed analytical results are reported in the characterization of each final compound.
4-(Phenethylamino)-2,2-diphenylbutanenitrile (12). A suspension of 4-bromo-2,2- diphenylbutanenitrile (500 mg, 1.67 mmol), 2-phenylethan-1- amine (605 mg, 5 mmol), and K2CO3 (230 mg, from 1.67 mmol up to 10 equivalents) in ACN (50 mL), was heated at 130 °C in a sealed vessel overnight. The mixture was filtered, the solvent removed under vacuum, and the residue purified by flash chromatography eluting with 15% DMA. The desired product was obtained as a colorless oil (300 mg, 53% yield). 1H NMR (400 MHz, CDCl3) δ 7.36 - 7.18 (m, 15H), 3.74 (t, J = 7.1 Hz, 2H), 3.07 (t, J = 6.2 Hz, 2H), 2.95 (t, J = 7.2 Hz, 2H), 2.60 (t, J = 6.2 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 171.34, 142.74, 139.55, 128.86, 128.57, 128.46, 128.38, 128.36, 128.12, 126.98, 126.18, 61.47, 53.40, 46.66, 46.18, 37.35, 33.47. The free base was converted into the corresponding oxalate salt. HRMS (C24H24N2 + H+) calculated 341.20123, found 341.20048 (error -0.7 ppm). CHN (C24H24N2+ 1.5 H2C2O4 + H2O) calculated C 65.71, H 5.92, N 5.68; found C 65.76, H 5.77, N 5.57. M.P: Salt too hygroscopic to determine melting point.
4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)-2,2-diphenylbutanenitrile (13). The reaction was performed following the same procedure described for 12, starting from 1-(2,3- dichlorophenyl)piperazine (250 mg, 0.9 mmol) and 4-bromo-2,2-diphenylbutanenitrile (350 mg, 1.17 mmol). The desired product was purified by flash chromatography eluting with hexanes/ethyl acetate (hex/EtOAc 5:5), and obtained as a colorless oil (30 mg, 7.5% yield). 1H NMR (400 MHz, CDCl3) δ 7.45 - 7.23 (m, 10H), 7.19 - 7.08 (m, 2H), 6.94 (dd, J = 6.8, 2.8 Hz, 1H), 3.04 (br s, 4H), 2.65 (dd, J = 10.5, 4.3 Hz, 6H), 2.57 - 2.49 (m, 2H). The free base was converted into the corresponding oxalate salt. CHN (C26H25N3CI2+ H2C2O4 + 0.25 H2O) calculated C 61.71, H 5.09, N 7.71; found C 61.67, H 5.09, N 7.85. mp: 202-207 °C.
4-((4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)butyl)amino)-2,2- diphenylbutanenitrile (14). The reaction was performed following the same procedure described for 12, starting from 4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butan-1-amine(200 mg, 0.7 mmol) and 4-bromo-2,2-diphenylbutanenitrile (105 mg, 0.35 mmol). The desired product was purified by flash chromatography eluting with 15% DMA, and obtained as a colorless oil (58 mg, 31% yield). 1H NMR (400 MHz, CDCl3) δ 7.37 - 7.29 (m, 10H), 7.29 - 7.18 (m, 2H), 6.95 (dd, J = 6.4, 3.2 Hz, 1H), 4.84 (br s, 1H), 3.52 (t, J = 7.2 Hz, 2H), 3.26 (t, J = 6.2 Hz, 2H), 3.05 (t, J = 4.8 Hz, 4H), 2.71 (t, J = 6.2 Hz, 2H), 2.59 (br s, 4H), 2.44 (dd, J = 8.2, 6.7 Hz, 2H), 1.70 - 1.53 (m, 4H); 13C NMR (101 MHz, CDCl3) δ 171.46, 151.32, 142.37, 133.99, 128.51, 128.45, 127.48, 127.39, 127.15, 124.48, 118.56, 61.65, 58.24, 53.24, 51.31, 46.34, 44.72, 37.36, 25.14, 24.26. The free base was converted into the corresponding oxalate salt. HRMS (C30H34N4O2 + H+) calculated 521.22333, found 521.22363 (error 0.3 ppm). CHN (C30H34N4CI2+ 3 H2C2O4+ 0.5 H2O) calculated C 54.01, H 5.16, N 7.00; found C 53.97, H 5.33, N 7.15. M.P: Salt decomposes above 80 °C.
4-((4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)-3-hydroxybutyl)amino)-2,2- diphenylbutanenitrile (15). The reaction was performed following the same procedure described for 12, starting from 4-amino-1-(4-(2,3-dichlorophenyl)piperazin-1-yl)butan-2-ol Michino et al. “Toward Understanding the Stmctural Basis of Partial Agonism at the Dopamine D3 Receptor” J Med Chem 2017, 60 (2), 580-593) (223 mg, 0.7 mmol) and 4- bromo-2,2-diphenylbutanenitrile (105 mg, 0.35 mmol). The desired product was purified by flash chromatography eluting with 15% DMA, and obtained as a colorless oil (53 mg, 28% yield). 1H NMR (400 MHz, CDCl3) δ 7.48 - 7.32 (m, 6H), 7.24 - 7.10 (m, 6H), 6.95 (dd, J = 7.2, 2.3 Hz, 1H), 4.22 - 4.06 (m, 3H), 3.75 - 3.67 (m, 2H), 3.12 (br s, 4H), 2.96 (tt, J = 8.1, 4.2 Hz, 4H), 2.76 (d, J = 10.7 Hz, 2H), 2.67 (dd, J = 12.5, 3.2 Hz, 1H), 2.61 - 2.50 (m, 1H), 2.01 (s, 1H), 1.82 (ddd, J = 16.4, 13.9, 7.1 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ 169.96, 150.78, 138.44, 138.40, 134.10, 129.50, 129.48, 128.91, 128.89, 127.88, 127.78, 127.58, 127.43, 124.83, 118.64, 64.45, 63.72, 62.31, 53.36, 50.83, 50.62, 45.63, 37.82, 31.51. HRMS (C30H34N4CI2 + H+) calculated 537.21824, found 537.21935 (error 1 ppm). HPLC analysis method A: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 30% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 4.944 min, purity >94.3% (absorbance at 254 nm). HPLC analysis method B: Chiralpak OZ-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 30% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 9.072 and 10.862 min, purity >95%, er 43:57 (absorbance at 254 nm).
4-(Dimethylamino)-2,2-diphenylbutanenitrile (16). The reaction was performed following the same procedure described for 12, starting from dimethylamine hydrochloride (2 g, 25 mmol) and 4-bromo-2,2-diphenylbutanenitrile (5 g, 16.7 mmol). The desired product was purified by flash chromatography eluting with 5% DMA, and obtained as a colorless oil (3.5 g, 79% yield). 1H NMR (400 MHz, CDCl3) δ 7.66 - 6.75 (m, 10H), 2.68 - 2.50 (m, 2H), 2.50 - 2.33 (m, 2H), 2.25 (s, 6H). GC/MS (El), Rt 10.499 min; 264.1 (M+), purity >95%. The free base was converted into the corresponding oxalate salt. CHN (C18H20N2 + H2C2O4) calculated C 67.78, H 6.26, N 7.90; found C 67.66, H 6.43, N 7.96. mp: 163-169 °C.
3-Carboxy-A%V-dimethyl-3,3-diphenylpropan-1-aminiuin bromide (17). Compound 16 (2 g, 7.6 mmol) was dissolved in 48% HBr aq solution (50 mL) and stirred under reflux overnight. The solution was concentrated to half- volume, decanted and the residue washed multiple times with Et2O. The dried crude material was used in the next step without further purification. N-(4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)butyl)-4-(dimethylamino)-2,2- diphenylbutanamide (18). A solution of 17 (460 mg, 1.26 mmol), EDC hydrochloride (240 mg, 1.26 mmol), HOBt (170 mg, 1.26 mmol) and DIPEA (2.2 mL; 12.6 mmol) in DCM (20 mL) was stirred at RT for 1 h, followed by dropwise addition of 4-(4-(2,3- dichlorophenyl)piperazin-1-yl)butan-1-amine (380 mg, 1.26 mmol) in DCM (20 mL). The mixture was stirred at RT overnight, the solvent evaporated under vacuum and the residue purified by flash chromatography eluting with 10% DMA. The desired product was obtained as a yellow oil (40 mg, 6% yield). 1H NMR (400 MHz, CDCl3) δ 7.36 - 7.20 (m, 10H), 7.18 - 7.08 (m, 2H), 6.94 (dd, J = 6.6, 3.0 Hz, 1H), 6.74 (br s, 1H), 3.31 - 3.14 (m, 2H), 3.03 (br s, 4H), 2.62 - 2.53 (m, 6H), 2.40 - 2.27 (m, 2H), 2.19 (m, 8H), 1.53 - 1.36 (m, 4H); 13C NMR (101 MHz, CDCl3) δ 173.99, 151.26, 143.81, 133.99, 128.74, 128.25, 127.47, 127.40,
126.81, 124.51, 118.55, 60.22, 58.03, 55.98, 53.23, 51.28, 45.53, 45.42, 44.87, 39.71, 36.80, 29.40, 27.36, 24.09. The free base was converted into the corresponding oxalate salt. HRMS (C32H40ON4CI2 + H+) calculated 567.26519, found 567.26524 (error 1.3 ppm). CHN (C32H40ON4CI2 + 2 H2C2O4 + 3 H2O) calculated C 53.93, H 6.29, N 6.99; found C 53.89, H 5.90, N 7.31. Salt too hygroscopic to determine melting point.
6-(Dimethylamino)-4,4-diphenylhexan-3-one (19). Ethyl magnesium bromide (3 M solution in diethyl ether, 10 mmol) was added dropwise to a solution of 16 (2 g, 7.5 mmol) in toluene (30 mL) at 0 °C. The mixture was slowly warmed to RT and then stirred at reflux for 3 h. The reaction was quenched with 10 mL of 2N HCl (aq solution) at 0 °C and stirred at reflux for for 30 min. The suspension was basified with 2N NaOH at 0 °C, the toluene removed under vacuum and the aq phase extracted with DCM/2-PrOH (3:1). The organic layers were combined, dried over Na2SO4, fdtered and dried under vacuum to afford the crude material, which was purified by flash chromatography eluting with 10% DMA. The desired product was obtained as a colorless oil (1.3 g, 59%). 1H NMR (400 MHz, CDCl3) d 7.51 - 7.06 (m, 10H), 2.52 (m, 2H), 2.30 (m, 2H), 2.15 (d, J = 0.9 Hz, 6H), 1.95 (m, 2H),
0.88 (td, J = 13, 0.9 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 211.02, 141.48, 129.14, 128.26, 126.94, 65.04, 55.67, 45.52, 35.41, 32.47, 9.05. The free base was converted into the corresponding oxalate salt. HRMS (C20H25NO + H+) calculated 296.20089, found 296.20150 (error 0.4 ppm). CHN (C20H25NO + H2C2O4) calculated C 68.55, H 7.06, N 3.63; found C 68.51, H 7.15, N 3.62. mp: 161-165 °C. tert- Butyl (5-(4-(2,3-dichlorophenyl)piperazin-1-yl)-5-oxopentyl)carbamate (20).
A solution of 5-(( tert-butoxycarbonyl)amino)pentanoic acid (470 mg, 2.16 mmol), 1-(2,3- dichlorophenyl (piperazine (500 mg, 2.16 mmol) and HCTU (895 mg, 2.16 mmol) in DCM (25 mL) was stirred at RT for 3 h. The solvent was removed under vacuum and the residue purified by flash chromatography eluting with hex/EtOAc (40/60). The desired product was obtained as a yellow oil (550 mg, 59% yield). 1H NMR (400 MHz, CDCl3) δ 7.23 - 7.11 (m, 2H), 6.92 (dd, J = 7.7, 1.8 Hz, 1H), 4.63 (br s, 1H), 3.79 (t, J = 4.9 Hz, 2H), 3.68 - 3.60 (m, 2H), 3.15 (q, J = 6.6 Hz, 2H), 3.00 (dq, J = 10.7, 5.2 Hz, 4H), 2.39 (t, J = 7.4 Hz, 2H), 1.76 - 1.62 (m, 2H), 1.60 - 1.51 (m, 2H), 1.43 (s, 9H).
4-((5-(4-(2,3-Dichlorophenyl)piperazin-1-yl)-5-oxopentyl)amino)-2,2- diphenylbutanenitrile (21). Trifluoroacetic acid (1 mL, 12.8 mmol) was added to a solution of 20 (550 mg, 1.28 mmol) in DCM (10 mL). The mixture was stirred at RT for 24 h, basified with 2N NaOH and extracted with DCM. The organic layers were combined, dried over Na2SO4 filtered and dried under vacuum to afford the crude primary amine intermediate, which was dissolved in ACN (20 mL), followed by addition of 4-bromo-2,2- diphenylbutanenitrile (384 mg, 1.28 mmol) and K2CO3 (10 equivalents). The reaction mixture was stirred at reflux overnight, filtered and the solvent removed under vacuum. The residue was purified by flash chromatography eluting with 15% DMA, and the desired product obtained as a yellow oil (20 mg, 3% yield). 1H NMR (400 MHz, CDCl3) δ 7.37 - 7.10 (m, 12H), 6.90 (dd, J = 7.8, 1.8 Hz, 1H), 3.78 (d, J = 5.8 Hz, 2H), 3.63 (t, J = 4.9 Hz, 2H), 3.59 - 3.51 (m, 2H), 3.28 (t, J = 6.2 Hz, 2H), 2.97 (dt, J = 9.3, 5.0 Hz, 4H), 2.72 (t, J = 6.2 Hz, 2H), 2.50 - 2.41 (m, 2H), 1.71 (m, 4H); 13C NMR (101 MHz, CDCl3) δ 171.48, 171.42, 150.64, 142.20, 134.16, 128.51, 128.47, 128.43, 127.74, 127.50, 127.25, 125.13, 118.75, 61.72, 51.69, 51.20, 46.41, 45.80, 44.41, 41.73, 37.36, 32.69, 26.68, 22.47. HRMS (C31H34ON4CI2 + H+) calculated 549.21824, found 549.21825 (error 0.0 ppm). HPLC analysis method: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 30% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 27.693 min, purity >95% (absorbance at 254 nm).
4-(Dimethylamino)-N,N-dimethyl-2,2-diphenylbutanamide (22). Dimethylamine hydrochloride (1.18 g, 14.5 mmol) was added to a suspension of N-( 3,3- diphenyldihydrofuran-2(3H)-ylidene)-N-methylmethanaminium bromide (500 mg, 1.45 mmol) and K2CO3 (2.0 g, 14.5 mmol) in TBME/ACN (25 mL/10 mL). The reaction mixture was heated in a sealed vessel for 24 h, the solvent removed under vacuum, and the residue purified by flash chromatography eluting with EtOAc/MeOH (95/5). The desired product was obtained as a colorless oil (70 mg, 16% yield). 1H NMR (400 MHz, CDCl3) δ 7.43 - 7.24 (m, 10H), 2.97 (br s, 3H), 2.57 - 2.46 (m, 2H), 2.30 (m + br s, 2H + 9H). GC/MS (El), Rt 11.256 min; 310.1 (M+), purity >95%. The free base was converted into the corresponding oxalate salt. HRMS (C20H26ON2 + H+) found 311.21098 (error -2.4 ppm). CHN (C20H26ON2 + 1.5 H2C2O4 + 0.75 H2O) calculated C 60.19, H 6.70, N 6.10; found C 60.09, H 6.36, N 6.13. mp: 174-178 °C.
4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)-N,N-dimethyl-2,2-diphenylbutanamide (23). 1-(2,3-Dichlorophenyl)piperazine hydrochloride (400 mg, 1 mmol) was added to a suspension ofN-(3,3-diphenyldihydrofuran-2(3H)-ylidene)-N-methylmethanaminium bromide (500 mg, 1 mmol), K2CO3 (1 g, 7 mmol) and DIPEA (1 mL, 7 mmol) in ACN (20 mL). The reaction mixture was stirred at reflux overnight, the solvent removed under vacuum and the residue purified by flash chromatography eluting with 5% DMA. The desired product was obtained as a colorless oil (640 mg, 91% yield). 1H NMR (400 MHz, CDCl3) δ 7.46 - 7.34 (m, 10H), 7.34 - 7.20 (m, 2H), 7.15 - 7.03 (m, 1H), 2.97 (br s, 6H), 2.56 - 2.43 (m, 8H), 2.19 - 2.10 (m, 2H), 1.69 (s, 2H); 13C NMR (101 MHz, CDCl3) δ 173.41, 151.42, 140.76, 133.89, 128.35, 128.10, 127.44, 127.30, 126.70, 124.29, 118.54, 59.70, 55.71, 53.16, 51.33, 42.24. The free base was converted into the corresponding oxalate salt. HRMS (C28H31ON3CI2 + H+) calculated 496.19169, found 496.19052 (error -2.3 ppm). CHN (C28H31ON3CI2 + 1.5 H2C2O4) calculated C 58.96, H 5.43, N 6.65; found C 58.69, H 5.33, N 6.65. mp: 195-200 °C.
4-(7-Cyano-3,4-dihydroisoquinolin-2(1H)-yl)-N,N-dimethyl-2,2- diphenylbutanamide (24). The reaction was performed following the same procedure described for 23, starting from 1,2,3,4-tetrahydroisoquinoline-7-carbonitrile (100 mg, 0.63 mmol). The crude material was purified by flash chromatography eluting with 5% DMA and the desired product was obtained as a colorless oil (130 mg, 40% yield). 1H NMR (400 MHz, CDCl3 δ) 7.46 - 7.18 (m, 12H), 7.10 (d, J = 7.9 Hz, 1H), 3.49 (br s, 2H), 2.98 (br s, 3H), 2.82 (t, J = 5.9 Hz, 2H), 2.63 (t, J = 5.9 Hz, 2H), 2.55 - 2.46 (m, 2H), 2.40 - 2.26 (br s, 3H), 2.26 - 2.17 (m, 2H); 13C NMR (101 MHz, CDCl3) δ 173.44, 140.62, 140.46, 136.71, 130.29, 129.39, 129.33, 128.42, 128.39, 128.07, 126.80, 119.18, 109.08, 59.74, 55.45, 55.42, 50.18, 42.84, 29.55. The free base was converted into the corresponding oxalate salt. HRMS (C28H29ON3 + H+) calculated 424.23834, found 424.23765 (error -1.6 ppm). CHN (C28H29ON3 + 1.5 H2C2O4 + 0.5 H2O) calculated C 65.60, H 5.86, N 7.40; found C 65.76, H 5.87, N 7.29. mp 178-181 °C.
4-Hydroxy-N,N-dimethyl-2,2-diphenylbutanamide (25). N-( 3,3- Diphenyldihydrofuran-2(3H)-ylidene)-N-methylmethanaminium bromide (700 mg, 2 mmol) was suspended in 2N NaOH (15 mL aq solution) and then stirred at RT for 5 min. The mixture was extracted with DCM, the organic layers were combined, dried over Na2SO4, filtered and evaporated under vacuum to afford the pure desired product in quantitative yield, as a colorless oil. 1H NMR (400 MHz, CDCl3) δ 7.48 - 7.25 (m, 10H), 3.17 (q, J = 5.0 Hz, 2H), 3.04 - 2.95 (m, 3H), 2.57 - 2.49 (m, 2H), 2.35 - 2.27 (m, 3H). GC/MS (El), Rt 11.847 min; 283.1 (M+).
AVV-Dimethyl-4-oxo-2,2-diphenylbutanamidc (26). DMP was added portion- wise to a solution of 25 (200 mg, 0.71 mmol) in DCM (10 mL) at 0 °C. The reaction mixture was slowly warmed to RT and stirred for 1 h. The suspension was washed with 10% NaHCO3 (aq solution), the organic layer dried over Na2SO4, filtered and evaporated under vacuum. The residue was purified by flash chromatography eluting with Hex/EtOAc (50/50) to afford the desired product as a white solid (120 mg, 60% yield). H NMR (400 MHz, CDCl3) δ 9.17 (t, J = 2.2 Hz, 1H), 7.46 - 7.25 (m, 10H), 3.11 - 2.99 (m, 6H), 2.33 (s, 2H). GC/MS (El), Rt 11.744 min; 281.1 (M+).
N,N-Dimethyl-4-(phenethylamino)-2,2-diphenylbutanamide (27). A solution of 26 (90 mg, 0.32 mmol), 2-phenylethan-1-amine (77 mg, 0.64 mmol) and cat. AcOH in DCE (5 mL) was stirred at RT for 30 min. STAB (97 mg, 0.48 mmol) was added portion-wise and the mixture stirred for additional 2 h. The solvent was removed under vacuum and the residue purified by flash chromatography eluting with 5% DMA. The desired product was obtained as a colorless oil (quantitative yield). 1H NMR (400 MHz, CDCl3) δ 7.39 - 7.10 (m, 15H), 2.96 (m, 3H), 2.75 (br s, 7H), 2.48 - 2.28 (m + br s, 4H + 1H); 13C NMR (101 MHz, CDCl3) d 176.89, 173.88, 140.40, 139.18, 128.82, 128.73, 128.54, 128.45, 128.04, 126.94, 126.22, 126.17, 60.51, 50.11, 46.28, 44.40, 43.46, 40.00, 35.13, 23.25. The free base was converted into the corresponding oxalate salt. HRMS (C26H30ON2 + H+) calculated 387.24309, found 387.24226 (error -2.1 ppm). CHN (C26H30ON2+ 1.5 H2C2O4 + 0.1 NH4OH) calculated C 66.33, H 6.43, N 5.60; found C 66.10, H 6.61, N 5.91. mp: 112-117 °C.
4-((4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)butyl)amino)-N,N-dimcthyl-2,2- diphenylbutanamide (28). The reaction was performed following the same procedure described for 27, starting from 4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butan-1-amine (272 mg, 0.9 mmol). The desired product was purified by flash chromatography eluting with 25% DMA and obtained as a colorless oil (300 mg, 65% yield). H NMR (400 MHz, CDCl3) d 7.41 - 7.33 (m, 7H), 7.28 - 7.26 (m, 3H), 7.15 - 7.13 (m, 2H), 7.00 - 6.90 (m, 1H), 3.05 (s, 4H), 2.98 (s, 3H), 2.62 (br s, J = 6.0 Hz, 3H), 2.51 (t, J = 6.8 Hz, 6H), 2.45 - 2.37 (m, 4H), 2.29 (br s, 3H), 1.62 - 1.49 (m, 4H); 13C NMR (101 MHz, CDCl3) δ 178.09, 173.97, 151.17, 139.95, 133.94, 128.69, 128.65, 127.97, 127.48, 127.38, 127.15, 124.55, 118.73, 60.48,
57.93, 53.14, 51.06, 50.67, 47.97, 45.70, 43.25, 25.94, 24.19, 23.98. The free base was converted into the corresponding oxalate salt. HRMS (C32H40ON4CI2 + H+) calculated 567.26519, found 567.26458 (error -1.1 ppm). CHN (C32H40ON4CI2 + 2.5 H2C2O4 + H2O) calculated C 54.82, H 5.84, N 6.91; found C 54.89, H 5.68, N 6.83. M.P: Salt too hygroscopic to determine melting point.
4-((4-(4-(2,3-Dichlorophcnyl)piperazin-1-yl)-3-hydroxybutyl)amino)-N,N- dimethyl-2, 2-diphenylbutanamide (29). The reaction was performed following the same procedure described for 27, starting from 4-amino- 1-(4-(2, 3-dichlorophenyl)piperazin-1- yl)butan-2-ol (130 mg, 0.41 mmol). The desired product was purified by flash chromatography eluting with 25% DMA and obtained as a colorless oil (80 mg, 34% yield). 1H NMR (400 MHz, CDCl3) δ 7.37 (m, 8H), 7.31 - 7.22 (m, 2H), 7.16 - 7.07 (m, 2H), 6.93 (dd, J = 6.5, 3.1 Hz, 1H), 3.82 (m, 1H), 3.04 (br s, 6H), 2.97 (br s, 1H), 2.83 - 2.67 (m, 4H), 2.59 (dt, J = 11.8, 6.1 Hz, 4H), 2.50 - 2.30 (m, 4H), 2.30 - 2.17 (m, 4H), 1.56 - 1.32 (m,
2H); 13C NMR (101 MHZ, CDCl3) δ 173.53, 151.32, 140.75, 140.71, 133.98, 128.38, 128.33,
128.12, 128.09, 128.04, 127.48, 127.36, 126.71, 126.68, 124.45, 118.56, 71.43, 68.18, 64.64, 62.95, 59.92, 53.04, 52.17, 51.35, 47.60, 47.30, 45.64, 43.84, 34.82, 34.04. HPLC analysis method A: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 11.906 and 12.953 min, purity >99%, er 38:62 (absorbance at 254 nm). HPLC analysis method B: Chiralcel OD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 12.011 min, purity >99% (absorbance at 254 nm). HPLC analysis method C: Chiralcel OZ-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 12.172 min, purity >95% (absorbance at 254 nm). The free base was converted into the corresponding oxalate salt. HRMS (C32H40O2N4CI2 + H+) calculated 583.26011, found 583.26204 (error 2.3 ppm). CHN (C32H40O2N4CI2 + 2 H2C2O4 + 1.5 H2O) calculated C 54.69, H 5.99, N 7.09; found C 54.75, H 5.71, N 7.16. mp: Salt decomposes above 116 °C.
4-(4-(2-Chloro-3-ethylphenyl)piperazin-1-yl)-N,N-dimethyl-2,2- diphenylbutanamide (30). The reaction was performed following the same procedure described for 27, starting from 1-(2-chloro-3-ethylphenyl)piperazine (Kumar et al. 2016) (120 mg, 0.53 mmol). The desired product was purified by flash chromatography eluting with 15% DMA and obtained as a colorless oil (130 mg, 50% yield). H NMR (400 MHz, CDCl3) 5 7.44 - 7.34 (m, 8H), 7.29 (m, 2H), 7.13 (t, J = 7.8 Hz, 1H), 6.91 (ddd, J = 19.7, 7.8, 1.5 Hz, 2H), 3.07 (br s, 6H), 2.99 (br s, 2H), 2.74 (br s + q, 4H + 2H), 2.61 - 2.52 (m, 2H), 2.38 (m, 4H), 1.20 (t, J = 7.5 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 175.46, 173.36, 148.98, 143.16,
140.12, 128.63, 128.54, 128.49, 128.06, 126.98, 126.87, 124.19, 118.14, 59.68, 55.36, 52.67, 50.17, 40.52, 27.39, 22.19, 14.03. The free base was converted into the corresponding oxalate salt. HRMS (C30H36ON3CI + H+) found 490.26239 (error 0.9 ppm). CHN (C30H36ON3CI +
1.5 H2C2O4) calculated C 63.40, H 6.29, N 6.72; found C 63.35, H 6.46, N 6.67. mp: 183-186 °C. 4-((4-(4-(2-Chloro-3-ethylphenyl)piperazin-1-yl)butyl)amino)-N,N-dimethyl-2,2- diphenylbutanamide (31). The reaction was performed following the same procedure described for 27, starting from 4-(4-(2-chloro-3-ethylphenyl)piperazin-1-yl)butan-1-amine (390 mg, 1.33 mmol). The desired product was purified by flash chromatography eluting with 15% DMA and obtained as a colorless oil (90 mg, 12% yield). 1H NMR (400 MHz, CDCl3 d 7.43 - 7.30 (m, 8H), 7.30 - 7.21 (m, 2H), 7.13 (t, J = 7.8 Hz, 1H), 6.92 (ddd, J = 8.1, 6.6, 1.6 Hz, 2H), 3.03 (br s, 6H), 2.97 (br s, 2H), 2.76 (q, J = 7.5 Hz, 2H), 2.48 - 2.38 (m, 4H), 2.38 - 2.30 (m, 6H), 2.30 - 2.22 (m, 4H), 1.51 - 1.40 (m, 2H), 1.40 - 1.31 (m, 2H), 1.21 (t, J = 7.5 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 173.52, 149.69, 143.14, 140.85, 128.66, 128.32, 128.07, 126.83, 126.64, 123.85, 117.99, 59.90, 58.56, 53.42, 51.55, 49.76, 47.50, 45.75, 28.20, 27.46, 24.72, 23.03, 14.09. The free base was converted into the corresponding oxalate salt. HRMS (C34H45ON4CI + H+) calculated 561.33547, found 561.33350 (error -4.4 ppm). CHN (C34H45ON4CI + 2 H2C2O4 + 1.75 H2O) calculated C 59.06, H 6.85, N 7.25, found C 59.09, H 6.65, N 7.17.
4-((4-(4-(2-Chloro-3-ethylphenyl)piperazin-1-yl)-3-hydroxybutyl)amino)-N,N- dimethyl-2, 2-diphenylbutanamide (32). The reaction was performed following the same procedure described for 27, starting from 4-amino-1-(4-(2-chloro-3-ethylphenyl)piperazin-1- yl)butan-2-ol (166 mg, 0.53 mmol). The desired product was purified by flash chromatography eluting with 25% DMA and obtained as a colorless oil (110 mg, 36% yield). 1H NMR (400 MHz, CDCl3) δ 7.43 - 7.32 (m, 7H), 7.32 - 7.22 (m, 3H), 7.13 (t, J = 7.8 Hz, 1H), 6.92 (ddd, J= 11.9, 7.8, 1.6 Hz, 2H), 3.82 (m, 1H), 3.03 (s, 6H), 2.98 (s, 2H), 2.82 - 2.69 (m, 5H), 2.61 (ddd, J = 11.7, 8.1, 5.3 Hz, 3H), 2.47 - 2.19 (m, 8H), 1.58 - 1.34 (m, 2H), 1.22 (t, J = 7.5 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 173.55, 149.65, 143.17, 140.71, 128.67, 128.39, 128.05, 126.82, 126.72, 123.88, 117.98, 67.91, 64.64, 59.97, 53.73, 51.60, 47.48, 47.22, 45.49, 34.03, 27.45, 14.07. HPLC analysis method A: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 20% 2- PrOH in hexanes; flow rate: 1 mL /min; injection volume: 20 μL; sample concentration: ~1 mg/mL ; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 8.242 and 9.055 min, purity >99%, er 37:63 (absorbance at 254 nm). HPLC analysis method B: Chiralcel OD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210- 280 nm, Rt 8.516 and 9.788 min, purity >99%, er 57:43 (absorbance at 254 nm). HPLC analysis method C: Chiralcel OZ-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 8.886 and 9.524 min, purity >99%. er 50:50 (absorbance at 254 nm). The free base was converted into the corresponding oxalate salt. HRMS (C34H45O2N4CI + H+) found 577.33059 (error 0.4 ppm). CHN (C34H45O2N4CI + 2 H2C2O4 + H2O) calculated C 58.87, H 6.63, N 7.23, found C 59.06, H 6.46, N 7.14. mp: 126- 130 °C.
2-(4-Amino butyl)-1,2,3,4-tetrahydroisoquinoline-7-carbonitrile (33). A suspension of 1,2,3,4-tetrahydroisoquinoline-7-carbonitrile (300 mg, 1.9 mmol), N-(4- bromobutyl)phthalimide (535 mg, 1.9 mmol), cat. KI (3.15 mg, 19 μmol) and K2CO3 (2.6 g, 19 mmol) in ACN (20 mL) was stirred under reflux overnight. The reaction mixture was cooled down to RT, filtered, and the solvent removed under vacuum and the residue dissolved in EtOH (10 mL), followed by addition of hydrazine (0.175 mL). The solution was stirred under reflux for 3 h, EtOH was evaporated, the residue diluted with 20% K2CO3 aq solution and extracted with DCM. The organic layers were combined, dried over Na2SO4, filtered and evaporated under vacuum. The crude material was used in the next step without further purification (300 mg, 94% yield).
4-((4-(7-Cyano-3,4-dihydroisoquinolin-2(1H)-yl)butyl)amino)-N,N-dimethyl-2,2- diphenylbutanamide (34). The reaction was performed following the same procedure described for 27, starting from 33 (300 mg, 1.31 mmol) and 26 (368 mg, 1.31 mmol). The desired product was purified by flash chromatography eluting with 10% DMA and obtained as a colorless oil (300 mg, 46% yield). 1H NMR (400 MHz, CDCl3) δ 7.42 - 7.21 (m, 12H), 7.16 (d, J = 7.9 Hz, 1H), 3.57 (s, 2H), 3.47 (d, J = 0.7 Hz, 6H), 2.99 - 2.87 (m, 4H), 2.68 (t, 7 = 5.9 Hz, 2H), 2.49 - 2.35 (m, 7H), 1.50 (q, J = 7.7 Hz, 2H), 1.41 (q, J = 7.3 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 173.55, 140.74, 140.36, 136.37, 130.37, 129.50, 129.46, 128.35, 128.04, 126.69, 119.13, 109.29, 59.89, 58.00, 55.45, 50.77, 50.10, 49.57, 47.45, 45.64, 29.41, 27.93, 24.82. The free base was converted into the corresponding oxalate salt. HRMS (C32H38ON4 + H+) found 495.31212 (error 0.5 ppm). CHN (C34H45O2N4CI + 2 H2C2O4 + 1.5 H2O) calculated C 61.61, H 6.46, N 7.98, found C 61.59, H 6.36, N 7.98. mp: Salt decomposes above 134 °C.
(S)-3-Chloro-N-((1-(3-cyano-3,3-diphenylpropyl)pyrrolidin-2-yl)methyl)-5-ethyl- 6-hydroxy-2-methoxybenzamide (35). The reaction was performed following the same procedure described for 12, starting from (S)-nor-eticlopride (250 mg, 0.8 mmol) and 4- bromo-2,2-diphenylbutanenitrile (240 mg, 0.8 mmol). The desired product was purified by flash chromatography eluting with hex/EtOAc (60/40) and obtained as a colorless oil (98 mg, 23% yield). 1H NMR (400 MHz, CDCl3) δ 13.78 (s, 1H), 8.74 (s, 1H), 7.44 - 7.19 (m, 11H), 3.86 (s, 3H), 3.62 (ddd, J = 14.0, 6.9, 2.6 Hz, 1H), 3.29 - 3.12 (m, 2H), 2.89 - 2.78 (m, 1H), 2.72 - 2.55 (m, 5H), 2.49 - 2.37 (m, 1H), 2.28 (q, J = 8.8 Hz, 1H), 1.90 (dq, J = 12.3, 8.1 Hz, 1H), 1.75 (t, J = 7.8 Hz, 2H), 1.67 - 1.51 (m, 1H), 1.32 - 1.15 (m, 3H); 13C NMR (101 MHz, CDCl3) δ 169.44, 160.15, 152.40, 140.02, 139.45, 132.90, 130.91, 128.95, 128.01, 127.97, 126.64, 122.00, 116.06, 108.18, 62.15, 61.44, 54.04, 50.33, 50.08, 40.43, 38.52, 29.68, 28.12, 22.71, 22.55, 13.43. CHN (C31H34N3O3CI + 0.4 hexanes) calculated C 70.81, H 7.05, N 7.42; found C 70.49, H 7.15, N 7.08. HPLC analysis method A: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: gradient from 10% to 40% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 7.799 min, purity >99%, ee >99% (absorbance at 254 nm). HPLC analysis method B: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 10% 2- PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: -1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 9.043 min, purity >99%, ee >99% (absorbance at 254 nm). HRMS (C31H34N3O3CI + H+) calculated 532.23615, found 532.23691 (error 0.4 ppm).
(S)-N-((1-(4-Aminobutyl)pyrrolidin-2-yl)methyl)-3-chloro-5-ethyl-6-hydroxy-2- methoxybenzamide (36). The reaction was performed following the same procedure described for 33, starting from (S)-3-chloro-5-ethyl-6-hydroxy-2-methoxy-N-(pyrrolidin-2- ylmethyl)benzamide ((S)-nor-eticlopride 250 mg, 0.8 mmol). The crude material was used in the next step without further purification (110 mg, 36% yield).
(S)-3-Chloro-N-((1-(4-((3-cyano-3,3-diphenylpropyl)amino)butyl)pyrrolidin-2- yl)methyl)-5-ethyl-6-hydroxy-2-methoxybenzamide (37). The reaction was performed following the same procedure described for 12, starting from 36 (110 mg, 0.29 mmol) and 4- bromo-2,2-diphenylbutanenitrile (78 mg, 0.26 mmol). The desired product was purified by flash chromatography eluting with 10% DMA and obtained as a colorless oil (15 mg, 10% yield). 1H NMR (400 MHz, CDCl3 + CD3OD) 7 δ.39 - 7.23 (m, 6H), 7.18 - 7.06 (m, 5H), 3.83 (s, 3H), 3.82 - 3.50 (m, 6H), 3.36 - 3.26 (m, 6H), 2.82 (p, J = 6.9 Hz, 2H), 2.53 (q, J = 7.5 Hz, 2H), 1.74 (m, 5H), 1.11 (ddd, J = 8.2, 7.1, 0.8 Hz, 3H); 13C NMR (101 MHz, CDCl3) d 174.69, 163.12, 156.56, 143.10, 142.99, 137.03, 134.45, 132.70, 132.67, 132.08, 132.06, 131.89, 131.85, 120.19, 112.47, 67.26, 66.39, 64.97, 57.87, 54.60, 49.82, 43.72, 42.16, 31.41, 27.77, 27.47, 26.07, 25.77, 16.57. HPLC analysis method A: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: gradient from 10% to 40% 2- PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 22.362 min, purity >95%, ee >99% (absorbance at 254 nm). HPLC analysis method B: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 30% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD a λbsorbance signals measured in the range of 210- 280 nm, Rt 14.389 min, purity >99%, ee >99% (absorbance at 254 nm). HRMS
(C35H43N4O3CI + 2H)2+ found 302.15901; (C35H43N4O3CI + H+) calculated 603.30965, found 603.31020 (error 0.4 ppm). tert- Butyl ((1-(4-(1,3-dioxoisoindolin-2-yl)butyl)pyrrolidin-2- yl)methyl)carbamate (38). A suspension of tert-butyl (pyrrolidin-2-ylmethyl)carbamate (500 mg, 2.5 mmol), N-(4-bromobutyl)phthalimide (775 mg, 2.75 mmol), cat. KI (4.15 mg, 25 μmol) and K2CO3 (3.45 g, 25 mmol) in ACN (20 mL) was stirred under reflux overnight. The reaction mixture was cooled down to RT, filtered, and the solvent removed under vacuum, the desired product, presenting both N-Boc and N-phthalimide protecting groups, was purified by flash chromatography eluting with 10% DMA and obtained as a yellow oil (940 mg, 85% yield). 1H NMR (400 MHz, CDCl3) 7 δ.84 (dd, J = 5.5, 3.0 Hz, 2H), 7.71 (dd, J = 5.5, 3.1 Hz, 2H), 5.00 - 4.95 (m, 1H), 3.77 - 3.64 (m, 2H), 3.27 (d, J = 10.9 Hz, 1H), 3.15 - 2.99 (m, 2H), 2.73 (dt, J = 11.9, 8.1 Hz, 1H), 2.47 (br s, 1H), 2.23 - 2.02 (m, 2H), 1.89 - 1.43 (m, 8H), 1.43 (s, 9H).
3-Chloro-N-((1-(4-(l,3-dioxoisoindolin-2-yl)butyl)pyrrolidin-2-yl)methyl)-5- ethyl-6-hydroxy-2-methoxybenzamide (39). A solution of 38 (940 mg, 2.34 mmol) and TFA (2.5 mL) in DCM (15 mL) was stirred at RT for 3 h. The reaction was quenched with NaHCO3 (sat. aq solution) and extracted with DCM/2-PrOH (3:1). The organic layers were combined, dried over Na2SO4, filtered and evaporated under vacuum. The crude material was dissolved in DCM (15 mL), followed by dropwise addition of a solution of 3-chloro-5-ethyl- 6-hydroxy-2-methoxybenzoic acid (De Paulis et al.) (647 mg, 2.81 mmol) and HCTU (1.16 g, 2.81 mmol) in DCM (15 mL). The reaction mixture was stirred at RT for 48 h, the solvent was removed under vacuum and the crude material purified by flash chromatography eluting with 5% DMA. The desired product was obtained as a brown oil (310 mg, 26% yield). 1H NMR (400 MHz, CDCl3) δ 13.12 (s, 1H), 9.11 (s, 1H), 7.80 (dd, J = 5.4, 3.0 Hz, 2H), 7.69 (dd, J = 5.5, 3.0 Hz, 2H), 7.26 - 7.15 (m, 1H), 3.96 - 3.78 (m, 5H), 3.72 (m, J = 14.0 Hz,
4H), 3.57 (br s, 1H), 3.48 (br s, 1H), 3.26 (br s, 2H), 2.66 - 2.51 (m, 3H), 2.22 (dt, J = 15.0, 7.6 Hz, 1H), 1.99 (tt, J = 13.4, 6.9 Hz, 2H), 1.80 - 1.60 (m, 3H), 1.18 (dt, J = 10.7, 7.5 Hz, 3H).
3-Chloro-N-((1-(4-((4-(dimethylamino)-4-oxo-3,3- diphenylbutyl)amino)butyl)pyrrolidin-2-yl)methyl)-5-ethyl-6-hydroxy-2- methoxybenzamide (40). Hydrazine (0.2 mL, 50-60% wt. in H2O) was added to a solution of 39 (310 mg, 0.6 mmol) in EtOH (20 mL) and the solution was stirred at reflux for 3 h. The solvent was removed under vacuum, the residue diluted with 20% K2CO3 aq solution and extracted with DCM. The organic layers were combined, dried over Na2SO4, filtered and evaporated under vacuum. The obtained crude material was dissolved in DCE (10 mL) and added to a solution of 26 (169 mg, 0.6 mmol) and catalytic AcOH in DCE (10 mL). The mixture was stirred for 10 min at RT and STAB (190 mg, 0.9 mmol) was added portionwise. The reaction was stirred for additional 12 h, the solvent was removed under vacuum and the residue purified by flash chromatography eluting with 10% DMA. The desired product was obtained as a colorless oil (80.5 mg, 21% yield). 1H NMR (400 MHz, CDCl3) δ 8.79 (br s, 1H), 7.40 - 7.22 (m, 11H), 3.82 (s, 3H), 3.72 (dt, J = 12.1, 4.0 Hz, 2H), 3.28 - 3.19 (m, 1H), 3.14 (dt, J = 9.5, 4.5 Hz, 1H), 2.95 (br s, 3H), 2.74 - 2.52 (m, 3H), 2.47 - 2.35 (m, 4H), 2.25 (d, J = 14.1 Hz, 4H), 2.12 (q, J = 8.6 Hz, 3H), 1.93 - 1.80 (m, 1H), 1.72 (d, J = 7.8 Hz, 2H), 1.69 - 1.52 (m, 1H), 1.40 (dt, J = 16.4, 8.3 Hz, 4H), 1.20 (dt, J = 27.3, 7.3 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 173.62, 169.49, 160.11, 152.51, 140.71, 140.65, 132.82, 130.67,
128.37, 128.17, 128.16, 128.03, 126.72, 116.01, 108.17, 62.27, 61.41, 60.04, 54.01, 53.80, 49.38, 47.15, 45.23, 40.32, 28.10, 27.73, 26.57, 22.58, 22.51, 13.41. HPLC analysis method A: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 30% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD a λbsorbance signals measured in the range of 210- 280 nm, Rt 9.538 and 10.664 min, purity >99%, er 46:54 (absorbance at 254 nm). HPLC analysis method B: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 15% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD ab λ sorbance signals measured in the range of 210-280 nm, Rt 22.250 and 25.814 min, purity >99%, er 50:50 (absorbance at 254 nm). HRMS (C37H49N4O4CI + 2H)2+ found 325.18021, (C37H49N4O4CI + H+) calculated 649.35151, found 649.35221 (error 1.0 ppm).
3,3-Diphenylpyrrolidine (41). A suspension of LAH (0.56 g, 14.8 mmol) in THF (50 mL) was cooled to 0 °C and a solution of 4-bromo-2,2-diphenylbutanenitrile (1.5 g, 5 mmol) in THF (20 mL) was added dropwise. The mixture was stirred at RT for 15 h, quenched with MeOH (5 mL) and sat. aq NaHCO3 solution (5 mL), filtered over celite and concentrated under vacuum. The residue was suspended in DCM and washed with sat. Na2CO3 solution. The organic layer was dried over Na2SO4, filtered and evaporated under vacuum. The crude material was purified by flash chromatography eluting with 10% DMA. The desired product was obtained as a yellow oil (0.450 g, 40% yield). 1H NMR (400 MHz, CDCl3) 7.3 δ4 - 7.22 (m, 8H), 7.22 - 7.13 (m, 2H), 3.52 (s, 2H), 3.13 (t, J = 7.2 Hz, 2H), 2.80 - 2.70 (br s, 1H), 2.52 (t, J = 7.2 Hz, 2H). GC/MS (El), Rt 9.987 min; 223.2 (M+). 1-Methyl-3,3-diphenylpyrrolidine (42). Methyl chloroformate (85 mg, 69 μL, 0. 9 mmol) was added dropwise to a solution of 41 (100 mg, 0.45 mmol) in THF (10 mL ), followed by excess of DIPEA (5 eq.). The mixture was stirred at RT for 1 h, the solvent evaporated under vacuum and the residue dissolved in THF (10 mL). This solution was added dropwise to a suspension of LAH (17 mg, 0.45 mmol) in THF (10 mL), at 0 °C. The mixture was warmed to RT, quenched with MeOH/2N aq NaOH (1:1 ratio, 2 mL), filtered over celite, and the solvents were evaporated under vacuum. The crude material was purified by flash chromatography eluting with 10% DMA to afford the desired product as a colorless oil (60 mg, 56% yield). 1H NMR (400 MHz, CDCl3) δ 7.26 (d, J = 4.6 Hz, 8H), 7.20 - 7.11 (m, 2H), 3.22 (s, 2H), 2.82 (td, J = 7.0, 0.6 Hz, 2H), 2.60 (dd, J = 7.7, 6.7 Hz, 2H), 2.42 (s, 3H). GC/MS (El), Rt 9.650 min; 237.2 (M+), purity >99%.
1-(3,3-Diphenylpyrrolidin-1-yl)propan-1-one (43). A solution of 41 (70 mg, 0.31 mmol), propionyl chloride (58 mg, 0.63 mmol) and DIPEA (5 eq) in DCM (10 mL) was stirred under reflux overnight. The solvent was removed under vacuum and the residue purified by flash chromatography eluting with hex/EtOAc (70/30). The desired product was obtained as a colorless oil (25 mg, 29% yield). 1H NMR (400 MHz, CDCl3) rotamer conformations observed (60:40; rotamer A: rotamer B) 7 δ.34 - 7.14 (m, 10H), 4.16 (s, 2H, rotamer A), 4.04 (s, 2H, rotamer B), 3.53 (t, J = 6.9 Hz, 2H, rotamer B), 3.42 (t, J = 6.7 Hz, 2H, rotamer A), 2.63 (t, J = 6.7 Hz, 2H, rotamer A), 2.52 (t, J = 6.9 Hz, 2H, rotamer B), 2.41 (q, J = 7.5 Hz, 2H, rotamer B), 2.26 (q, J = 7.5 Hz, 2H, rotamer A), 1.21 (t, J = 7.5 Hz, 3H, rotamer B), 1.16 (t, J = 7.5 Hz, 3H, rotamer A). GC/MS (El), Rt 12.154 min; 279.1 (M+), purity >99%.
2-Chloro-1-(3,3-diphenylpyrrolidin-1-yl)ethan-1-one (44). 2-Chloroacetyl chloride (126 mg, 1.12 mmol) was added dropwise to a solution of 41 (250 mg, 1.12 mmol) in THF (10 mL) at 0 °C, followed by dropwise addition of DIPEA (0.3 mL, 1.68 mmol). The mixture was allowed to warm to RT and stirred for 1 h. The solvent was removed under vacuum and the residue used in the following step without further purification. GC/MS (El), Rt 12.740 min; 299.1 (M+). tert- Butyl ((1-(2-(3,3-diphenylpyrrolidin-1-yl)-2-oxoethyl)pyrrolidin-2- yl)methyl)carbamate (45). A mixture of 44 (290 mg, 0.97 mmol), tert-butyl (pyrrolidin-2- ylmethyl)carbamate (194 mg, 0.97 mmol), KI (161 mg, 0.97 mmol) and K2CO3 (1.34 g, 9.67 mmol) in ACN (25 ml) was stirred under reflux for 3 h. The mixture was filtered, the solvent evaporated under vacuum and the residue purified by flash chromatography eluting with 10% DMA. The desired product was obtained as a yellow oil (330 mg, 74% yield). H NMR (400 MHz, CDCI3) rotamer conformations observed δ 7.34 - 7.15 (m, 10H), 5.30 (m, 1H), 3.69 - 3.38 (m, 4H), 3.29 - 2.93 (m, 3H), 2.71 - 2.17 (m, 4H), 1.90 (tt, J = 19.2, 8.6 Hz, 2H), 1.73 (m,J = 17.3, 8.5 Hz, 4H), 1.50 - 1.38 (m, 9H).
3-Chloro-N-((1-(2-(3,3-diphenylpyrrolidin-1-yl)-2-oxoethyl)pyrrolidin-2- yl)methyl)-5-ethyl-6-hydroxy-2-methoxybenzamide (46). TFA (0.3 mL) was added to a solution of 45 (330 mg, 0.71 mmol) in DCM (10 mL). The mixture was stirred at RT for 2 h, basified with NH4OH (28% aq solution) and extracted with DCM. The organic layers were combined, dried over Na2SO4, filtered and evaporated under vacuum to afford the crude material, which was filtered over a silica pad, eluting and washing with 25% DMA to isolate the desired primary amine intermediate. The amine was dissolved in DCM (10 mL) and added dropwise to a solution of 3-chloro-5-ethyl-6-hydroxy-2-methoxybenzoic acid (70 mg, 0.3 mmol), HCTU (0.2 g, 0.33 mmol) and DIPEA (1.5 eq) in DCM (10 mL). The mixture was stirred at RT for 3 h, the solvent was removed under vacuum and the residue purified by flash chromatography eluting with 5% DMA. The desired product was obtained as a colorless oil (26 mg, 15% yield). 1H NMR (400 MHz, CDCl3) rotamer conformations observed δ 13.68 (s, 1H), 8.82 (s, 1H), 7.31 - 7.12 (m, 11H), 4.23 (t, J = 11.0 Hz, 1H), 4.02 (dd, J = 26.1, 11.5 Hz, 1H), 3.85 (ds, J = 17.4 Hz, 3H), 3.79 - 3.68 (m, 1H), 3.62 - 3.21 (m, 6H), 2.96 (br s,
1H), 2.68 - 2.52 (m, 4H), 2.14 - 1.97 (m, 1H), 1.92 - 1.66 (m, 4H), 1.28 - 1.14 (m, 3H); 13C NMR (101 MHz, CDCl3) rotamer conformations observed δ 169.75, 160.07, 160.04, 152.47, 152.46, 144.94, 144.88, 144.79, 133.07, 130.79, 130.77, 128.57, 128.53, 128.51, 126.67, 126.62, 126.59, 126.58, 126.52, 116.16, 116.11, 107.98, 61.57, 61.49, 56.60, 56.14, 56.12, 55.10, 54.87, 54.68, 54.45, 53.40, 52.22, 44.57, 44.39, 40.88, 40.46, 37.52, 35.57, 29.68, 28.38, 28.26, 23.05, 22.86, 22.51, 13.39. HPLC analysis method A: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 10% 2- PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD λ absorbance signals measured in the range of 210-280 nm, Rt 20.539 and 23.859 min, purity >99%, er 51:49 (absorbance at 254 nm). HRMS (C33H38N3O4CI + H+) calculated 576.26236, found 576.26297 (error 1.0 ppm).
3-Chloro-N-(((2S,4R)-4-(4-((4-(dimethylamino)-4-oxo-3,3- diphenylbutyl)amino)butoxy)pyrrolidin-2-yl)methyl)-5-ethyl-6-hydroxy-2- methoxybenzamide (48). A solution of 47 (Shaik, A. B. et al, unpublished data) (400 mg,
0.8 mmol), 26 (225 mg, 0.8 mmol) and cat. AcOH (0.05 eq) in DCE (20 mL) was stirred at RT for 1 h, followed by portion-wise addition of STAB (339 mg, 1.6 mmol). The mixture was stirred at RT for 3 h, basified with 10% NH4OH in MeOH, the solvent evaporated under vacuum and the residue purified by flash chromatography eluting with 10% DMA. The obtained intermediate was dissolved in DCM (20 mL) and TFA (10 mL), and the solution was stirred at RT overnight. The excess of TFA was removed under vacuum, the residue resuspended in aq NH4OH (pH 9) and extracted with DCM/2-PrOH (3:1). The organic layers were combined, dried over Na2SO4, filtered and evaporated to afford the crude material, which was purified by flash chromatography eluting with 25% DMA. The desired product was obtained as a colorless oil (45 mg, 8.5% yield). 1H NMR (400 MHz, CDCl3) 8.92 δ (s, 1H), 7.43 - 7.21 (m, 11H), 3.97 (t, J = 4.9 Hz, 1H), 3.89 (s, 3H), 3.57 (dq, J = 9.6, 4.7 Hz, 3H), 3.36 (dt, J = 5.8, 2.8 Hz, 3H), 3.22 (tt, J = 8.9, 4.5 Hz, 2H), 3.02 - 2.90 (m, 5H), 2.69 - 2.55 (m, 4H), 2.45 (dd, J = 21.5, 5.7 Hz, 4H), 2.30 (br s, 2H), 2.00 (dd, J = 13.7, 6.9 Hz, 1H), 1.70 - 1.50 (m, 5H), 1.31 - 1.14 (m, 3H); 13C NMR (101 MHz, CDCl3) δ 174.57, 169.21, 160.06, 152.48, 139.97, 132.89, 130.72, 128.78, 127.96, 127.93, 127.26, 116.16, 108.17, 80.67, 68.17, 61.57, 56.10, 51.78, 43.34, 36.07, 27.16, 22.50, 21.93, 13.41. HPLC analysis method: Chiralpak AD-H analytical column (4.5mm x 250mm - 5 μm particle size); mobile phase: isocratic 20% 2-PrOH in hexanes; flow rate: 1 mL/min; injection volume: 20 μL; sample concentration: ~1 mg/mL; multiple DAD a λbsorbance signals measured in the range of 210-280 nm, Rt 18.518 min, purity >95%, ee >95% (absorbance at 210 nm). The free base was converted into the corresponding oxalate salt. HRMS (C37H49N4O5CI + 2H)2+ calculated 333.17685, found 333.17656 (error 0.9 ppm), (C37H49N4O5CI + H)+ calculated 665.34642, found 665.34552 (error 1.4 ppm). CHN (C37H49N4O5CI + 2 H2C2O4 + 1.5 H2O) calculated C 56.45, H 6.47, N 6.42; found C 56.25, H 6.24, N 6.40. mp: Salt decomposes above 90 °C.
Scheme 9
Figure imgf000053_0001
Figure imgf000054_0001
a) imidazole, tert-butylchlorodimethylsilane, DCM:DMF (4:1); b) borane-methyl sulfide complex, THF, from 0 C to room temperature; c) Dess-Martin periodinane (DMP), DCM, from 0 C to room temperature; d) sodium triacetoxyborohydride (STAB), cat. acetic acid (AcOH), DCM, 2N aq. NaOH; e) 1M TBAF, THF; f) trifluoroacetic acid (TFA):DCM (1:2); g) STAB, cat. AcOH, DCE.
(2S,4R)-1-(tert-butoxycarbonyl)-4-((tert-butyldimethylsilyl)oxy)pyrrolidine-2- carboxylic acid (60) tert-butylchlorodimethylsilane (6.5 g, 43.2 mmol) was added portion- wise to a solution of (2S,4R)-1-(tert-butoxycarbonyl)-4-hydroxypyrrolidine-2-carboxylic acid (N-Boc-trans-4-hydroxy-L-proline) (5.0 g, 21.6 mmol) and imidazole (2.9 g, 43.2 mmol) in DCM (20 mL) and DMF (5 mL). The reaction was stirred at room temperature (RT) for 2 hours, and the mixture was washed with 0.1N HC1 and sat. NH4CI, dried over Na2SO4, filtered, and evaporated. The residue was used in the following step without further purification (6.8 g, yield 91%). 1H NMR (400 MHz, CDCl3) δ 4.51 - 4.14 (m, 2H), 3.57 (ddd, J = 19.8, 11.0, 5.3 Hz, 1H), 3.33 (ddd, J = 41.1, 11.1, 3.9 Hz, 1H), 2.18 (dddd, J = 18.4, 13.3, 8.3, 5.3 Hz, 1H), 2.10 - 1.91 (m, 1H), 1.43 (2 x s, 9H), 0.99 - 0.73 (2 x s, 9H), 0.36 - 0.19 (2 x s, 6H). tert-butyl (2S,4R)-4-((tert-butyldimethylsilyl)oxy)-2-(hydroxymethyl)pyrrolidine-1- carboxylate (61) A solution of (2S,4R)-1-(tert-butoxycarbonyl)-4-((tert- butyldimethylsilyl)oxy)pyrrolidine-2-carboxylic acid (4.0 g, 11.6 mmol) was dissolved in THF (20 mL), followed by drop- wise addition of borane-methyl sulfide complex (58 mmol) at 0 C. The reaction mixture allowed to warm to room temperature and stirred overnight under argon atmosphere. The reaction was quenched with sat. NH4CI and extracted with EtOAc. The organic phase was dried over Na2SO4, filtered, and evaporated. The crude material was purified by flash chromatography, eluting with 40% EtOAc in hexanes, to yield the desired product (2.2 g, 57% yield). 1H NMR (400 MHz, CDCl3) δ 4.89 (d, J = 8.2 Hz, 1H), 4.28 (br s, 1H), 4.17 - 4.09 (m, 1H), 3.69 (t, J = 9.9 Hz, 1H), 3.54 (t, J = 9.5 Hz, 1H), 3.43 (d, J = 11.7 Hz, 1H), 3.34 (dd, J = 11.6, 4.1 Hz, 1H), 1.95 (m, 1H), 1.60 (m, 1H), 1.47 (s, 9H), 0.87 (s, 9H), 0.06 (s, 6H). tert-butyl(R)-4-((tert-butyldimethylsilyl)oxy)-2-((4-(2,3-dichlorophenyl)piperazin-1- yl)methylene)pyrrolidine-1-carboxylate (62) To a solution of tert-butyl (2S,4R)-4-((tert- butyldimethylsilyl)oxy)-2-(hydroxymethyl)pyrrolidine-1-carboxylate (2.2 g, 6.6 mmol) in DCM (30 mL) was added DMP (2.8 g, 1 Eq, 6.6 mmol) portion-wise at 0 C. The mixture was warmed to RT and stirred for 1 hour. The mixture was washed with sat. aq. NaHCO3, dried over Na2SO4 and filtered. To the filtered solution was added 3 drops of AcOH, followed by 1-(2,3-dichlorophenyl)piperazine (1.5 g, 6.6 mmol) and the reaction was stirred at RT for 30 min. Immediate precipitation of the iminium salt intermediate was observed, then sodium triacetoxyborohydride (1.4 g, 6.6 mmol) was added portion-wise. The precipitate never went back into DCM solution and thus the expected reduction never occurred. After 2 hours the reaction was quenched and washed with 2N NaOH and brine. The organic layer was dried, filtered, evaporated and the residue purified by flash chromatography. The enamine product eluted with 2% DMA (2% MeOH with 0.5% NH4OH, in DCM) (2.0 g, 55% yield). 1H NMR (400 MHz, CDCl3) δ 7.13 (m, 2H), 6.92 (t, J = 7.4 Hz, 1H), 4.39 (m, 1H), 4.01 (m, 1H), 3.38 (m, 2H), 3.02 (br s, 4H), 2.72 - 2.60 (m, 4H), 2.33 (dt, J = 13.6, 4.2 Hz, 1H), 1.99 (br s, 2H), 1.49 (m + s, 1H + 9H), 0.90 (m, 9H), 0.06 (dd, J = 4.2, 2.1 Hz, 6H).
(i?)-5-((4-(2,3-dichlorophenyl)piperazin-1-yl)methylene)pyrrolidin-3-ol (63) To a solution of tert-butyl (R )-4-((tert-butyldimethylsilyl)oxy)-2-((4-(2,3-dichlorophenyl)piperazin-1- yl)methylene)pyrrolidine-1-carboxylate (2.2 g, 4.1 mmol) in THF (20 mL) was added TBAF (1 M in THF; 12 mL, 12 mmol). The mixture was stirred for 45 min, until complete deprotection of the silyl ether was observed. The solvent was evaporated, and the residue dissolved in DCM (20 mL), followed by addition of TFA (10 mL). The mixture was stirred overnight at room temperature, the excess of TFA evaporated, the residue basified with 2N NaOH and extracted with DCM:2-PrOH (3:1). The organic phase was dried over Na2SO4, filtered, and evaporated. The crude material was used in the next step without further purification. (R)-4-(2-((4-(2,3-dichlorophenyl)piperazin-1-yl)methylene)-4-hydroxypyrrolidin-1-yl)- N,N-dimethyl-2,2-diphenylbutanamide (64) N,N-dimethyl-4-oxo-2,2-diphenylbutanamide (1.1 g, 3.9 mmol) was dissolved in DCE (15 mL), followed by addition of cat. AcOH (3-4 drops) and a solution of (R)-5-((4-( 2,3-dichlorophenyl)piperazin-1-yl)melhylene)pyrrolidin- 3-ol (1.3 g, 3.9 mmol) in DCE (15 mL). The mixture was stirred for 30 min, then STAB (0.83 g, 3.9 mmol) was added portion- wise. The reaction was stirred overnight at room temperature. The reaction was diluted with a solution of 0.5% NH4OH in MeOH, the solvents were evaporated, and the residue was purified by flash chromatography eluting with 10% DMA (0.57 g, 24% yield). 1H NMR (400 MHz, CDCl3) 7 δ.65 (br s, 1H), 7.57 (d, J = 1.6 Hz, 2H), 7.57 - 7.46 (m, 2H), 7.44 (dt, J = 9.2, 1.6 Hz, 1H), 7.37 (ddt, J = 12.4, 10.3, 3.1 Hz,
3H), 7.33 - 7.16 (m, 2H), 7.16 - 7.08 (m, 1H), 6.94 (dtd, J = 11.4, 5.7, 4.9, 2.9 Hz, 1H), 4.44 (br s, 1H), 3.79 (br s, 1H), 2.95 (m, 10H), 2.45 (2 x br s, 11H), 1.86 (dd, J = 28.4, 19.6 Hz, 3H). 13C NMR (101 MHz, CDCl3) 1 δ73.38, 152.41, 140.00, 135.06, 130.87, 129.30, 129.26, 129.08, 128.39, 128.12, 125.40, 119.54, 71.76, 64.13, 63.51, 54.56, 51.98, 41.43, 40.29, 38.49. The free base was converted into the corresponding oxalate salt. HRMS-MS/MS C33H38CI2N4O2 + H+ calculated 593.24446, found 593.24552. Elemental analysis ( C33H38CI2N4O2 + 2.5 H2C2O4+ 2.5 H2O) calculated C 52.84, H 5.60, N 6.49, found C 52.54, H 5.24, N 6.87.
Scheme 10
Figure imgf000056_0001
a) STAB, cat. AcOH, DCE; b) 1M TBAF, THE; c) TFA:DCM (1:2); d) STAB, cat. AcOH, DCE. tert-butyl(2S,4R)-4-((tert-butyldimethylsilyl)oxy)-2-((4-(6-(trifluoromethyl)pyridin-2- yl)piperazin-1-yl)methyl)pyrrolidine-1-carboxylate (65) The compound was prepared following the same procedure described for compound 64 starting from 1-(6- (trifluoromethyl)pyridin-2-yl)piperazine (0.94 g, 4.1 mmol). The desired product was partially purified by flash chromatography eluting with 40% EtOAc in hexanes (0.62 g, 25% yield) and used in the following step without further purification.
(3R,5S)-5-((4-(6-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)methyl)pyrrolidin-3-ol (66)
The compound was prepared following the same procedure described for compound 61 starting from tert-butyl (2S,4R)-4-((tert-butyldimethylsilyl)oxy)-2-((4-(6- (trifluoromethyl)pyridin-2-yl)piperazin-1-yl)methyl)pyrrolidine-l -carboxylate (0.62 g, 1.14 mmol). The crude material obtained was used in the following step without further purification.
4-((2S,4R)-4-hydroxy-2-((4-(6-(trifluoromethyl)pyridin-2-yl)piperazin-1- yl)methyl)pyrrolidin-1-yl)-N,N-dimethyl-2,2-diphenylbutanamide (67) The compound was prepared following the same procedure described for compound 64 starting from (3R,5S)-5-((4-(6-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)methyl)pyrrolidin-3-ol (200 mg, 0.61 mmol) and N,N-dimethyl-4-oxo-2,2-diphenylbutanamide (190 mg, 0.67 mmol). The desired product was isolated by flash chromatography eluting with 25% DMA (120 mg, 33% yield). 1H NMR (400 MHz, CDCh) δ 7.56 (t, J = 8.0 Hz, 1H), 7.43 - 7.29 (m, 8H), 7.28 - 7.19 (m, 2H), 6.93 (d, J = 73 Hz, 1H), 6.73 (d, J = 8.6 Hz, 1H), 4.36 - 4.28 (m, 1H), 3.44 (m, 5H), 2.88 (br s, 3H), 2.80 (m, 1H), 2.64 - 2.49 (m, 3H), 2.42 - 2.23 (m, 9H), 2.17 - 2.09 (m, 2H), 1.80 (m, 2H). 13C NMR (101 MHz, CDCh) 8 172.80, 158.26, 137.45, 127.75, 127.66, 127.23, 126.16, 126.06, 108.70, 108.07, 69.47, 61.55, 59.17, 52.64, 44.00, 39.88. The free base was converted into the corresponding oxalate salt. HRMS-MS/MS C33H40F3N5O2 + H+ calculated 596.32069, found 596.31987. Elemental analysis ( C33H40F3N5O2 + 2.5 H2C2O4+ 0.5 H2O) calculated C 55.00, H 5.59, N 8.44, found C 55.04, H 5.66, N 8.72 Scheme 11
Figure imgf000058_0001
a) appropriate aromatic piperazine, EDC HCl, HOBt, DIPEA, DCM; b) TFA:DCM (1:2); c) LAH, THF, from 0 C to room temperature; d) STAB, cat. AcOH, DCE. tert-butyl(2S,4R)-2-(4-(3-chloro-5-ethyl-2-methoxyphenyl)piperazine-1-carbonyl)-4- hydroxypyrrolidine-1-carboxylate (69) EDC HCl salt (0.23 g, 1.18 mmol) and HOBt (0.18 g, 1.18 mmol) were added to a solution of (2S, 4R)-1-(tert-butoxycarbonyl)-4- hydroxypyrrolidine-2-carboxylic acid (0.27 g, 1.18 mmol) in DCM (10 mL), followed by the addition of DIPEA (0.25 mL, 1.75 mmol). The mixture was stirred at room temperature for 30 min, followed by dropwise addition of 1-(3-chloro-5-ethyl-2-methoxyphenyl)piperazine (prepared by the method disclosed in J Med Chem. 2016 Aug 25;59(16):7634-50) (0.30 g, 1.18 mmol) dissolved in DCM (10 mL) and DIPEA (0.25 mL, 1.75 mmol). The reaction was stirred at room temperature for an additional 2 h. The solvents were evaporated, and the residue was purified by flash chromatography eluting with 10% DMA (0.50 g, 91% yield). 1H NMR (400 MHz, CDCl3) δ 6.90 (d, J = 7.8 Hz, 1H), 6.59 (s, 1H), 4.83 (dt, J = 34.4, 7.7 Hz, 1H), 4.52 (2 x br s, 1H), 3.85 (d, J = 3.1 Hz, 3H), 3.68 (dd, J = 27.6, 12.7 Hz, 4H), 3.49 (d, J = 2.1 Hz, 4H), 3.39 - 2.83 (m, 4H), 2.55 (d, = J 7.9 Hz, 2H), 1.45 (d, = 14 J.1 Hz, 9H), 1.20 (t, J = 7.6 Hz, 3H).3
(3R,5S)-5-((4-(3-chloro-5-ethyl-2-methoxyphenyl)piperazin-1-yl)methylpyrrolidine-3-ol (71) The intermediate was prepared by -Boc deprotection, mediated by TFA, as described for 63, starting from tert-butyl (2S, 4R )-2-(4-(3-chloro-5-ethyl-2-methoxyphenyl)piperazine-1- carbonyl)-4-hydroxypyrrolidine-1-carboxylate (500 mg, 1.07 mmol). The obtained crude material was immediately dissolved in THF (10 mL) and added dropwise to a stirring suspension of LAH (41 mg, 1.1 mmol) in THF (10 mL), at 0 C, under argon atmosphere. After the dropwise addition was completed, the reaction was allowed to warm to room temperature and stirred overnight. The mixture was cooled to 0 C, and the reaction quenched by slow dropwise addition of sat. aq. Na2SO4. The suspension was filtered, and the solvents evaporated to yield the crude material, which was used in the following step without further purification (290 mg, 77% yield)
4-((2S,4R)-2-((4-(3-chloro-5-ethyl-2-methoxyphenyl)piperazin-1-yl)methyl)-4- hydroxypyrrolidin-1-yl)-N,N-dimethyl-2,2-diphenylbutanamide (73) The compound was prepared following the general reductive amination procedure described for compound 64, starting from (3R,5S)-5-((4-(3-chloro-5-ethyl-2-methoxyphenyl)piperazin-1- yl)methyl)58yrrolidine-3-ol (290 mg, 0.819 mmol) and N,N-dimethyl-4-oxo-2,2- diphenylbutanamide (231 mg, 0.819 mmol). The desired product was isolated by flash chromatography eluting with 15% DMA (180 mg, 36% yield). 1H NMR (400 MHz, CDCl3) d 7.41 - 7.30 (m, 9H), 7.30 - 7.16 (m, 1H), 6.88 - 6.83 (s, 1H), 6.60 (s, 1H), 4.50 (q, = 3 J.6 Hz, 1H), 3.93 (dd, J = 12.4, 4.9 Hz, 1H), 3.78 (s + m, 3H + 1H), 3.56 (d, = 12 J.4 Hz, 1H), 2.95 (s, 3H), 2.85 (m, 7H), 2.70 - 2.53 (m, 6H), 2.37 - 2.22 (m, 6H), 1.98 (dd, J = 8.6, 5.6 Hz, 2H), 1.24 (t, J = 7.6 Hz, 3H). 13C NMR (101 MHz, CDCl3) 17 δ6.56, 176.52, 174.49, 173.37, 146.25, 146.06, 140.73, 128.86, 128.79, 128.20, 128.08, 127.87, 127.54, 127.43, 127.28, 122.15, 116.65, 92.93, 68.90, 60.78, 59.35, 58.93, 57.85, 53.43, 49.82, 40.34, 39.19, 38.57, 37.31, 28.55, 22.70, 15.53. The free base was converted into the corresponding oxalate salt. HRMS-MS/MS C36H47CIN4O3 + H+ calculated 619.34095, found 619.33962. Elemental analysis (C36H47CIN4O3 + 2 H2C2O4+ 2 H2O) calculated C 57.51, H 6.64, N 6.71, found C 57.44, H 6.26, N 6.64 tert-butyl (2S,4R)-2-(4-(2,3-dichlorophenyl)piperazine-1-carbonyl)-4- hydroxypyrrolidine-1-carboxylate (68) The compound was prepared following the same procedure described for 69, starting from 1-(2,3-dichlorophenyl)piperazine (1.2 g, 8.65 mmol). The desired product was isolated by flash chromatography eluting with 100% EtOAc (2.3 g, 60% yield). 1H NMR (400 MHz, CDCl3) δ 7.17 (ddd, J = 7.4, 4.6, 1.7 Hz, 2H), 6.96 - 6.88 (m, 1H), 4.91 - 4.76 (m, 1H), 4.51 (2 x br s, 1H), 3.87 (s, 2H), 3.79 - 3.66 (m, 4H), 3.61 - 3.50 (2 x d, J = 11.8, 11.7 Hz, 1H), 3.07 - 3.00 (m, 4H), 1.80 (m, 2H), 1.44 (dt, J = 13.5,
2.8 Hz, 9H).
(3R,5S)-5-((4-(2,3-dichlorophenyl)piperazin-1-yl)methyl)59yrrolidine-3-ol (72) The desired product was prepared as described for compound 73, starting from tert-butyl (2S,4R)- 2-(4-(2,3-dichlorophenyl)piperazine-1-carbonyl)-4-hydroxypyrrolidine-1-carboxylate (2.3 g, 5.18 mmol), and used in the following step without further purification (0.48 g, 99% yield).
4-((2S,4R)-2-((4-(2,3-dichlorophenyl)piperazin-1-yl)methyl)-4-hydroxypyrrolidin-1-yl)-
N,N-dimethyl-2,2-diphenylbutanamide (74) The desired product was prepared as described for compound 75, starting from (3R,5S)-5-((4-(2,3-dichlorophenyl)piperazin-1- yl)methyl)59yrrolidine-3-ol (780 mg, 2.37 mmol) and N,N-dimethyl-4-oxo-2,2- diphenylbutanamide (930 mg, 3.31 mmol), and isolated by preparative reverse phase HPLC (Phenomenex C-18 Gemini preparative HPLC column) eluting with a gradient starting from 10% ACN to 80% ACN in 2-PrOH + 0.1% TFA (flow rate 25-30 mL/min; injections of 4 mL at 15mg/mL) for a total run time of 60 min (324 mg, 17% yield). *H NMR (400 MHz,
CDCl3) δ 7.49 - 7.17 (m, 12H), 6.98 (dd, J = 7.9, 1.7 Hz, 1H), 4.53 (s, 1H), 4.16 (br s, 1H), 3.84 (d, J = 12.1 Hz, 1H), 3.52 (d, J = 13.3 Hz, 1H), 3.40 - 3.20 (m, 9H), 2.99 (br s, 4H),
2.86 (m, 2H), 2.70 (t, J = 11.5 Hz, 1H), 2.60 - 2.40 (m, 2H), 2.31 (s, 3H), 2.14 - 1.99 (m,
2H). 13C NMR (101 MHz, CDCl3) δ 173.49, 149.38, 139.49, 138.00, 134.33, 129.30, 129.20, 129.08, 128.34, 128.25, 127.95, 127.83, 127.72, 127.58, 125.91, 118.95, 68.77, 61.60, 60.20, 59.68, 56.72, 53.53, 48.67, 39.85, 39.51, 39.26, 37.36. HRMS-MS/MS C33H40CI2N4O2 + H+ calculated 595.26011, found 595.25984. Analytical HPLC: Agilent poroshell C-184.6 x 50 mm, 2.7 mm; gradient 10%-80% ACN in water + 0.1% TFA; 60 min run; injection 20 mL (1 mg/mL); temperature 40 C; Rt 22.862 min, purity >99% (at absorbance 1254 nm).
Scheme 12
Figure imgf000061_0001
Figure imgf000062_0001
a) 2-(4-bromobutyl)isoindoline-1,3-dione, K2CO3, ACN, reflux; b) NH2NH2, EtOH, reflux; c) EDCHCl, HOBt, DIPEA, DCM; d) 1M TBAF, THF; e) TFA:DCM (1:2); f) STAB, cat. AcOH, DCE.
2-(4-(4-(6-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)butyl)isoindolme-1,3-dione (77)
A solution of 1-(6-(trifluoromethyl)pyridin-2-yl)piperazine (5 g, 22 mmol), 2-(4- bromobutyl)isoindoline-1,3-dione (5.5 g, 20 mmol) and K2CO3 (15 g, 108 mmol) in ACN (100 mL) was stirred at reflux 3 h. The mixture was filtered, the solvent evaporated, and the desired product isolated by flash chromatography eluting with 5% DMA (4 g, 40% yield). 1H NMR (400 MHz, CDCl3) δ 7.76 (dd, J = 5.4, 3.1 Hz, 2H), 7.63 (dd, J = 5.5, 3.1 Hz, 2H), 7.49 (d, J = 8.0 Hz, 1H), 6.84 (d, J = 7.3 Hz, 1H), 6.67 (d, J = 8.7 Hz, 1H), 3.65 (t, J = 7.1 Hz,
2H), 3.51 (t, J = 5.1 Hz, 4H), 2.44 (t, J = 5.1 Hz, 4H), 2.34 (t, J = 7.6 Hz, 2H), 1.66 (t, J = 7.6 Hz, 2H), 1.54 - 1.45 (m, 2H). tert-butyl (2S,4R)-4-hydroxy-2-((4-(4-(6-(trifluoromethyl)pyridin-2-yl)piperazin-1- yl)butyl)carbamoyl)pyrrolidine-1-carboxylate (81) 2-(4-(4-(6-(trifluoromethyl)pyridin-2- yl)piperazin-1-yl)butyl)isoindoline-1,3-dione (4 g, 9.25 mmol) was dissolved in EtOH (25 mL ) and hydrazine (8.89 g, 8.71 mL, 278 mmol), and stirred at reflux for 3 h. The solvent was evaporated, the residue suspended in 20% aq. K2CO3 and extracted with DCM:2-PrOH (3:1). The organic phase was dried over Na2SO4, filtered, and evaporated. The crude material obtained was immediately reacted with (2S,4R)-1-(tert-butoxycarbonyl)-4- hydroxypyrrolidine-2-carboxylic acid (2.14 g, 9.25 mmol), following the same procedure described for AB08-94. The desired product was isolated by flash chromatography eluting with 5% DMA (3.2 g, 67% yield). (2S,4R)-1-(4-(dimethylamino)-4-oxo-3,3-diphenylbutyl)-4-hydroxy-N-(4-(4-(6- (trifluoromethyl)pyridin-2-yl)piperazin-1-yl)butyl)pyrrolidine-2-carboxamide (82) TFA
(25 mL) was added to a solution of tert-butyl (2S,4R)-4-hydroxy-2-((4-(4-(6- (trifluoromethyl)pyridin-2-yl)piperazin- 1 -yl)butyl)carbamoyl)pyrrolidine- 1 -carboxylate (1.83 g, 3.55 mmol) in DCM (50 mL), and stirred at room temperature until reaction completion. The solvent was evaporated, the residue was basified with 2N NaOH and extracted with DCM. The organic phase was dried over Na2SO4, filtered, and evaporated. The crude was immediately reacted with the aldehyde via reductive amination conditions as described for Compound 75. The desired product was isolated by flash chromatography eluting with 10% DMA (0.18 g, 15% yield). 1H NMR (400 MHz, CDCl3) 7 δ.57 (t, J = 8.0 Hz, 1H), 7.40 - 7.32 (m + br s, 8H), 7.26 (q, J = 2.6, 2.0 Hz, 3H), 6.94 (d, J = 7.4 Hz, 1H), 6.77 (d, J = 8.7 Hz, 1H), 4.29 (m, 1H), 3.62 (d, J = 5.9 Hz, 4H), 3.38 (dd, J = 10.6, 5.3 Hz, 1H), 3.20 (m,
3H), 2.96 (s, 3H), 2.53 (s, 4H), 2.43 - 2.18 (m, 8H), 2.08 (m, 2H), 1.91 (dt, J = 13.5, 7.0 Hz, 1H), 1.72 (br s, 2H), 1.50 (br s, 4H). 13C NMR (101 MHz, CDCl3) 173 δ.85, 173.20, 158.80, 140.60, 138.23, 128.52, 128.11, 127.86, 126.93, 109.38, 70.65, 66.42, 61.04, 59.73, 58.26, 53.67, 52.88, 44.71, 40.06, 38.62, 27.69, 24.18. The free base was converted into the corresponding oxalate salt. HRMS-MS/MS C37H47F3N6O3 + H+ calculated 681.37345, found 681.37253. Elemental analysis ( C37H47F3N6O3 + 2.5 H2C2O4 + H2O) calculated C 54.60, H 5.89, N 9.10, found C 54.74, H 5.72, N 9.10. Analytical HPLC: Agilent poroshell C-18 4.6 x 50 mm, 2.7 mm; gradient 10%-80% ACN in water + 0.1% TFA; 60 min run; injection 20 mL (1 mg/mL); temperature 40 C; Rt 20.759 min, purity >99% (at absorbance 1254 nm). tert-butyl (2S,4R)-4-((tert-butyllimethylsilyl)oxy)-2-((4-(4-(2,3- dichlorophenyl)piperazin-1-yl)butyl)carbamoyl)pyrrolidine-1-carboxylate (78) The compound was prepared following the same procedure described for compound 81 starting from (2S,4R)-1-(tert-butoxycarbonyl)-4-((tert-butyldimethylsilyl)oxy)pyrrolidine-2- carboxylic acid (1.7 g, 5.0 mmol) and 4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butan-1-amine (as described in Bioorg Med Chem Lett. 2003 Jul 7;13(13):2179-83) (1.5 g, 5.0 mmol). The desired product was isolated by flash chromatography eluting with 5% DMA (1.9 g, 61% yield). 1H NMR (400 MHz, CDCl3) δ 7.21 - 7.11 (m, 2H), 7.06 (br s, 1H), 7.02 - 6.92 (m, 1H), 4.36 (2 x br s, 2H), 3.45 - 3.39 (m, 1H), 3.35 (br s, 1H), 3.28 (br s, 1H), 3.08 (br s, 4H), 2.64 (br s, 4H), 2.44 (br s, 3H), 1.76 (br s, 2H), 1.51 (br s, 4H), 1.46 (s, 9H), 0.92 - 0.84 (m, 9H), 0.08 (br s, 6H). (2S,4R)-N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-4-hydroxypyrrolidine-2- carboxamide (79) The compound was prepared following the same procedure described for compound 63 starting from tert-butyl(2S,4R)-4-((tert-buiyldimethylsilyl)oxy )-2-((4-(4-(2,3- dichlorophenyl)piperazin-1-yl)butyl)carbamoyl)pyrrolidine-1-carboxylate (1.9 g, 3.0 mmol), and using consecutive deprotecting steps with TBAF (1M THF solution, 9 mL, 9 mmol) and TFA (1.2 mL, 15 mmol) in THF (25 mL) and DCM (30 mL), respectively. The crude material obtained was used in the following step without further purification. (2S,4R)-N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-1-(4-(dimethylamino)-4-oxo- 3,3-diphenylbutyl)-4-hydroxypyrrolidine-2-carboxamide (80) The compound was prepared following the same procedure described for compound 75 starting from (2S,4R)-N- (4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-4-hydroxypyrrolidine-2-carboxamide (1.48 g, 3.55 mmol). The desired product was isolated by flash chromatography eluting with 10% DMA (0.24 g, 10% yield). 1H NMR (400 MHz, CDCl3) 7 δ.57 (s, 1H), 7.40 - 7.29 (m, 7H), 7.29 - 7.23 (m, 3H), 7.21 - 7.11 (m, 2H), 7.00 (m, 1H), 4.30 (dq, J = 10.1, 4.8 Hz, 1H), 3.38 (dd,J = 10.3, 5.3 Hz, 1H), 3.19 - 3.11 (m, 9H), 2.96 (s, 3H), 2.75 (br s, 4H), 2.52 (d, J = 7.7 Hz, 2H), 2.44 - 2.30 (m, 6H), 2.11 (ddt, J = 12.9, 8.7, 5.1 Hz, 2H), 1.91 (ddd, J = 13.6, 8.0, 6.2 Hz, 1H), 1.60 (m, 4H). 13C NMR (101 MHz, CDCl3) 17 δ5.09, 173.77, 173.28, 150.90, 140.64, 139.73, 134.01, 128.55, 128.51, 127.78, 127.50, 127.48, 126.98, 126.93, 124.76, 118.69, 70.48, 66.36, 60.96, 59.76, 57.79, 53.64, 52.85, 50.62, 50.45, 44.50, 39.96, 39.13, 38.48, 37.19, 27.58, 23.41, 21.75. The free base was converted into the corresponding oxalate salt. HRMS-MS/MS C37H47CI2N5O3 + H+ calculated 680.31287, found 680.31183. Elemental analysis ( C37H47CI2N5O3 + 2 H2C2O4+ 2 H2O) calculated C 54.91, H 6.18, N 7.81, found C 54.77, H 5.87, N 7.63. Scheme 13
Figure imgf000065_0001
a) STAB, cat. AcOH, DCE; b) DMP, DCM, from 0 C to room temperature; c) STAB, cat. AcOH, DCE.
4-(5-(hydroxymethyl)-2-methylpiperidin-1-yl)-N,N-dimethyl-2,2-diphenylbutanamide
(83) The compound was prepared following the same procedure described for compound 75, starting from (6-methylpiperidin-3-yl)methanol (101 mg, 0.78 mmol) and N,N-dimethyl-4- oxo-2,2-diphenylbutanamide (220 mg, 0.78 mmol). The desired product was isolated by flash chromatography eluting with 10% DMA (170 mg, 55% yield). Diastereomeric ratio/excess and relative configurations have not been determined. 1H NMR (400 MHz, CDCl3) 7.51 δ — 7.24 (m, 10H), 3.62 (d, J = 11.4 Hz, 1H), 3.19 (d, J = 14.6 Hz, 1H), 2.99 (s, 3H), 2.74 - 2.61 (m, 5H), 2.29 (s, 3H), 2.04 - 1.87 (m, 3H), 1.77 (m, 3H), 1.55 (ddd, J = 14.3, 9.5, 4.8 Hz,
1H), 1.24 (td, J = 12.6, 10.8, 3.8 Hz, 1H), 1.14 (d, J = 6.3 Hz, 3H). 4-(5-((4-(2,3-dichlorophenyl)piperazin-1-yl)methyl)-2-methylpiperidin-1-yl)-N,N- dimethyl-2, 2-diphenylbutanamide (84) DMP was added portion-wise to a solution of 4-(5- (hydroxymethyl)-2-methylpiperidin-1-yl)-N,N-dimethyl-2, 2-diphenylbutanamide (60 mg, 0.15 mmol) in DCM (10 mL), at 0 C. The mixture was allowed to warm to room temperature and stirred for 2 h. The suspension was washed sat. aq. NaHCO3, the organic phase was dried over Na2SO4, filtered, and evaporated to yield the crude aldehyde, which was reacted with 1-
(2,3-dichlorophenyl)piperazine (42 mg, 0.18 mmol) following the same procedure described for compound 75. The desired product was isolated by preparative reverse phase HPLC (Phenomenex C-18 Gemini preparative HPLC column) eluting with a gradient starting from 10% ACN to 80% ACN in 2-PrOH + 0.1% TFA (flow rate 25-30 mL/min; injection of 4 mL - 10 mg/mL) for a total run time of 60 min (21 mg, 23% yield). Diastereomeric ratio/excess and relative configurations have not been determined. 1H NMR (400 MHz, CDCl3 ) 7.39 δ (m, 10H), 7.20 (dd, J = 17.4, 9.6 Hz, 3H), 6.99 (d, J = 7.8 Hz, 2H), 3.89 (br s, 1H), 3.71 (m, 2H), 3.41 - 3.22 (m, 5H), 2.98 (m + s, 1H + 3H), 2.85 (m, 5H), 2.54 (br s, 2H), 2.30 (s, 3H), 1.70 - 1.95 (m, 3H, 1.31 (m, 3H), 1.16 (d, J = 6.0 Hz, 3H). 13C NMR (101 MHz, CDCl3) 173 δ.26, 148.84, 138.91, 138.48, 134.34, 134.29, 129.15, 129.09, 127.98, 127.82, 127.78, 127.69, 126.18, 126.08, 119.14, 119.03, 60.05, 58.82, 58.48, 54.56, 51.42, 48.28, 47.94, 43.88, 39.26, 38.06, 37.38, 30.93, 29.66, 26.77, 17.25. HRMS-MS/MS C35H44CI2N4O + H+ calculated 607.29649, found 607.29620. Analytical HPLC: Agilent poroshell C-18 4.6 x 50 mm, 2.7 mm; gradient 10%-80% ACN in water + 0.1% TFA; 60 min run; injection 20 mL (1 mg/mL); temperature 40 C; Rt 22.013 min, purity >99% (at absorbance 1254 nm).
Figure imgf000066_0001
a) trimethyl phosphonoacetate, NaH, MeOH, from 0 C to room temperature; b) 5% cat. Pd/C, EtOH, TFA, ¾ 50 psi; c) LAH, THF, from 0 C to room temperature; d) STAB, cat. AcOH, DCE; e) DMP, DCM, from 0 C to room temperature; f) STAB, cat. AcOH, DCE. tert-butyl-3-(2-methoxy-2-oxoethylidene)pyrrolidine-1-carboxylate (85) Trimethyl phosphonoacetate (2.36 g, 13.0 mmol) was dissolved in MeOH (10 mL) and the solution was cooled to 0 C. Sodium hydride (0.33 g, 95% wt, 13.0 mmol) was added portion-wise and the mixture was allowed to warm to room temperature and stirred for 30 min, followed by drop- wise addition of tert-butyl 3-oxopyrrolidine-1-carboxylate (2.00 g, 10.8 mmol) dissolved in MeOH (10 mL). The reaction was stirred overnight at room temperature, quenched with addition of sat. aq. NH4CI, MeOH was evaporated, and the aq. layer extracted with DCM.
The organic phase was dried over Na2SO4, filtered, and evaporated. The desired product was isolated, as E and Z mixture, via flash chromatography, eluting with a gradient from 0% to 60% EtOAc in hexanes (0.92 g, 35% yield). GC/MS Rt 8.428 min, m/z 421.1 methyl 2-(pyrrolidin-3-yl)acetate (86) Pd/C (20.3 mg, 0.19 mmol) was added to a solution of tert-butyl-3-(2-methoxy-2-oxoethylidene)pyrrolidine-1-carboxylate (920 mg, 3.81 mmol) in EtOH (20 mL) and TFA (0.4 mL), and shaken in a Parr apparatus overnight at 50 psi ¾ pressure. The reaction was filtered over celite, the solvent was evaporated, the residue was dissolved in DCM and stirred for additional 30 min in presence of TFA (3 mL). The solution was evaporated, the residue suspended in 2N NaOH (pH>9), and extracted with DCM. The organic phase was dried over Na2SO4, filtered, and evaporated. The crude material obtained was used in the following step without further purification (350 mg, 64% yield). 1H NMR (400 MHz, CDCl3) δ 3.68 (s, 3H), 3.15 (dd, J = 10.5, 6.6 Hz, 1H), 2.99 - 2.88 (m, 2H), 2.56 - 2.35 (m, 4H), 2.06 - 1.93 (m, 2H), 1.38 (dq, J = 12.6, 7.3 Hz, 1H).
2-(pyrrolidin-3-yl)ethan-1-ol (87) LAH (280 mg, 7.33 mmol) was suspended in THF (10 mL), followed by dropwise addition of methyl 2-(pyrrolidin-3-yl)acetate (350 mg, 2.44 mmol) dissolved in THF (10 mL), at 0 C. the mixture was allowed to reach room temperature and stirred for 4 h. The reaction was quenched with sat. aq. Na2SO4, filtered and the solvent evaporated. The crude material was used without further purification.
4-(3-(2-hydroxyethyl)pyrrolidin-1-yl)-N,N-dimethyl-2,2-diphenylbutanamide (AB10-15) The compound was prepared following the same procedure described for compound 75, starting from 2-(pyrrolidin-3-yl)ethan-1-ol (240 mg, 2.08 mmol). The desired product was isolated by flash chromatography eluting with 25% DMA (40 mg, 5% yield). 1H NMR (400 MHz, CDCl3) δ 7.36 (m, 7H), 7.27 (m, 3H), 3.68 - 3.47 (m, 2H), 2.98 (s, 3H), 2.81 (td, J = 9.2, 4.5 Hz, 1H), 2.53 - 2.34 (m, 4H), 2.31 (m + s, 2H + 3H), 2.19 (q, J = 7.1 Hz, 2H), 2.02 (s, 1H), 1.96 - 1.82 (m, 1H), 1.65 (m, 1H), 1.57 - 1.46 (m, 2H).
4-(3-(2-(4-(2,3-dichlorophenyl)piperazin-1-yl)ethyl)pyrrolidin-1-yl)-N,N-dimethyl-2,2- diphenylbutanamide (89) The compound was prepared following the same procedure described for compound 84, starting with oxidation of 4-(3-(2-hydroxyethyl)pyrrolidin-1-yl)-
N,N-dimethyl-2,2-diphenylbutanamide (40 mg, 0.11 mmol) to aldehyde and subsequent reductive amination in presence of 1-(2,3-dichlorophenyl)piperazine hydrochloride (27 mg,
0.13 mmol). The desired product was isolated by preparative reverse phase HPLC (Phenomenex C-18 Gemini preparative HPLC column) eluting with a gradient starting from 10% ACN to 80% ACN in 2-PrOH + 0.1% TFA (flow rate 25-30 mL/min; injection of 4 mL - 5 mg/mL) for a total run time of 60 min (35 mg, 56% yield). H NMR (400 MHz, CDCl3) δ 7.41 - 7.33 (m, 10H), 7.27 - 7.12 (m, 2H), 7.01 - 6.93 (m, 1H), 3.66 (m, 3H), 3.38 (br s, 2H), 3.25 (br s, 2H), 3.08 (br s, 4H), 2.99 (m + s, 1H + 3H), 2.76 (br s, 3H), 2.54 (br d, J = 29.4 Hz, 3H), 2.30 (s, 3H), 2.23 (m, 1H), 1.96 (m, 2H), 1.80 (m, 2H). 13C NMR (101 MHz, CDCl3) δ 173.41, 168.32, 148.84, 141.38, 138.70, 138.53, 134.31, 132.72, 131.42, 129.07, 127.82, 127.77, 127.75, 127.73, 126.13, 119.04, 109.56, 94.43, 59.73, 58.38, 56.80, 55.50, 55.07, 53.93, 53.55, 52.64, 52.53, 52.52, 48.19, 40.77, 39.19, 37.30, 34.83, 34.37, 29.73, 28.83, 26.93, 26.73. HRMS-MS/MS C34H42CI2N4O + H+ calculated 593.28084, found 593.28053. Analytical HPLC: Phenomenex gemini C-18 4.6 x 50 mm, 3 mm; gradient 10%- 80% ACN in water + 0.1% TFA; 60 min run; injection 20 mL (1 mg/mL); temperature 40 C; Rt 19.638 min, purity 93% (at absorbance 1254 nm). Elemental analysis ( C34H42CI2N4O + 3.5 CF3COOH + 2.5 H2O) calculated C 47.45, H 4.91, N 5.40, found C 47.56, H 4.64, N 5.43.
Scheme 15
Figure imgf000069_0001
a) NaN3, DMF; b) copper(II) sulfate pentahydrate, sodium ascorbate, hex-5-yn-1-ol, THF:H2O; c) DMP, DCM, from 0 C to room temperature; d) STAB, cat. AcOH, DCE; e) 3- bromoprop-1-yne, K2CO3 , ACN, reflux; f) K2CO3 , ACN, reflux.
N,N-dimethyl-2,2-diphenyl-4-(4-(6-(trifluoromethyl)pyridin-2-yl)piperazin-1- yl)butanamide (90) A solution of N-(3,3-diphenyldihydrofuran-2(3H)-ylidene)-N- methylmethanaminium bromide (1.0 g, 2.89 mmol), 1-(6-(trifluoromethyl)pyridm-2- yl)piperazine (0.668 g, 2.89 mmol) and K2CO3 (2.0 g, 14.4 mmol) in ACN (20 mL) was stirred at reflux overnight. The mixture was filtered, the solvent was evaporated, and the residue was purified by flash chromatography, eluting with 5% DMA, to yield the desired product (0.950 g, 66% yield). 1H NMR (400 MHz, CDCl3) δ 7.51 (t, J = 8.0 Hz, 1H), 7.46 - 7.33 (m, 7H), 7.32 - 7.24 (m, 3H), 6.88 (d, J = 7.2 Hz, 1H), 6.69 (d, J = 8.7 Hz, 1H), 3.50 (t, J = 5.0 Hz, 4H), 2.98 (s, 3H), 2.51 - 2.38 (m, 6H), 2.35 (s, 3H), 2.16 - 2.07 (m, 2H). 13C NMR (101 MHz, CDCl3) δ 173.48, 158.81, 146.51, 146.17, 140.75, 138.07, 128.40, 128.13, 126.77, 123.00, 120.28, 116.65, 116.63, 116.59, 109.29, 108.53, 108.50, 59.78, 55.84, 53.42, 52.83, 44.77, 42.46, 39.17, 37.23. The free base was converted into the corresponding oxalate salt. HRMS-MS/MS C28H31F3N4O + H+ calculated 497.25227, found 497.25185. Elemental analysis ( C28H31F3N4O + H2C2O4) calculated C 61.43, H 5.67, N 9.55, found C 61.02, H 5.99, N 9.32.
4-azido-N,N-dimethyl-2,2-diphenylbutanamide (92) A solution of N-(3,3- diphenyldihydrofuran-2(3H)-ylidene)-N-methylmethanaminium bromide (2.0 g, 7.51 mmol) and sodium azide (0.488 g, 7.51 mmol) in DMF (10 mL) was stirred at room temperature, overnight.
The mixture was diluted with DCM and washed with brine. The organic phase was dried over Na2SO4, filtered and evaporated. The desired product was isolated by flash chromatography eluting with 20% EtOAc in hexanes (1.6 g, 69% yield). 1H NMR (400 MHz, CDCl3) 7.53 δ - 7.15 (m, 10H), 3.10 - 2.85 (m, 5H), 2.55 - 2.43 (m, 2H), 2.31 (s, 3H). GC/MS Rt 11.973, m/z 308.2.
4-(4-(4-hydroxybutyl)-1H-1,2,3-triazol-1-yl)-N,N-dimethyl-2,2-diphenylbutanamide (93) copper(II) sulfate pentahydrate (81.0 mg, 0.324 mmol) and sodium ascorbate (64.2 mg, 0.324 mmol) were added to a solution of 4-azido-N,N-dimethyl-2,2-diphenylbutanamide (500 mg, 1.62 mmol) and hex-5-yn-1-ol (159 mg, 1.62 mmol) in THF:water (1:1, 40 mL). The solvents were evaporated, and the desired product was partially purified by flash chromatography eluting with 10% DMA, then used in the following step without further purification (630 mg, 96% yield). 4-(4-(4-(4-(3-chloro-5-ethyl-2-methoxyphenyl)piperazin-1-yl)butyl)-1H-1,2,3-triazol-1- yl)-N,N-dimethyl-2,2-diphenylbutanamide (94) 4-(4-(4-hydroxybutyl)-1H-1,2,3-triazol-1- yl)-N,N-dimethyl-2,2-diphenylbutanamide (500 mg, 1.23 mmol) was oxidized to aldehyde, followed by reductive amination in presence of 1-(3-chloro-5-ethyl-2- methoxyphenyl)piperazine (313 mg, 1,23 mmol), as described for AB09-74. The desired product was isolated by flash chromatography eluting with 15% DMA (110 mg, 14% yield). 1H NMR (400 MHz, CDCl3) δ 7.44 - 7.34 (m, 7H), 7.34 - 7.22 (m, 4H), 6.84 (s, 1H), 6.61 (s, 1H), 4.06 - 3.98 (m, 3H), 3.82 (s, 3H), 3.63 (t, J = 6.4 Hz, 1H), 3.17 (br s, 3H), 3.02 (s, 3H), 2.79 - 2.64 (m, 8H), 2.58 - 2.45 (m, 3H), 2.33 (s, 3H), 1.75 - 1.54 (m, 4H), 1.18 (t, J = 7.6 Hz, 3H). 13C NMR (101 MHz, CDC13) 17 δ3.30, 147.60, 147.48, 146.37, 145.93, 140.86, 139.48, 128.82, 127.95, 127.31, 122.37, 120.88, 116.80, 62.45, 59.68, 59.09, 58.11, 53.43, 49.74, 48.32, 46.30, 39.14, 37.20, 32.19, 28.46, 27.32, 25.81, 25.52, 25.42, 25.24, 15.43. HRMS -MS/MS C37H47CIN6O2 + H+ calculated 643.35218, found 643.35140. Analytical HPLC: Agilent poroshell C-18 4.6 x 50 mm, 2.7 mm; gradient 10%-80% ACN in water + 0.1% TFA; 60 min ran; injection 20 mL (1 mg/mL); temperature 40 C; Rt 33.416 min, purity >95% (at absorbance 1254 nm). Elemental analysis ( C37H47CIN6O2 + H2O) calculated C 67.20, H 7.47, N 12.71, found C 67.49, H 7.23, N 12.36.
4-(4-((4-(3-chloro-5-ethyl-2-methoxyphenyl)piperazin-1-yl)methyl)-1H-1,2,3-triazol-1- yl)-N,N-dimethyl-2,2-diphenylbutanamide (91) A solution of 3-bromoprop-1-yne (158 mg, 1.06 mmol), 1 -(3-chloro-5-ethyl-2-methoxyphenyl)piperazine (300 mg, 1.18 mmol) and K2CO3 (1.63 g, 11.8 mmol) in ACN (20 mL) was stirred at reflux for 2 h. The mixture was filtered, and the solvent was evaporated. The residue, redissolved in DCM, was filtered through a silica plug and washed with 10% DMA. The obtained material was dried, and solubilized in THF:water (1:1, 20 mL), followed by addition of 4-azido-N,N-dimethyl-2,2- diphenylbutanamide (363 mg, 1.18 mmol), copper(II) sulfate pentahydrate (58.8 mg, 0.236 mmol) and sodium ascorbate (46.7 mg, 0.236 mmol). The reaction was stirred overnight at room temperature, the solvents evaporated and the desired product isolated by flash chromatography eluting with 15% DMA (90 mg, 13% yield). 1H NMR (400 MHz, CDCl3) δ 7.44 - 7.38 (s + m, 8H), 7.38 - 7.26 (m, 3H), 6.81 (s, 1H),
6.60 (s, 1H), 4.13 - 4.04 (m, 2H), 3.81 (s, 3H), 3.67 (s, 2H), 3.15 - 3.08 (m, 4H), 3.04 (s,
3H), 2.83 - 2.74 (m, 2H), 2.64 (m, 4H), 2.54 (q, J = 7.6 Hz, 2H), 2.34 (s, 3H), 1.24 - 1.15 (t, 7 = 7.6 Hz, 3H). 13C NMR (101 MHz, CDCl3) 17 δ3.27, 146.30, 146.11, 143.87, 140.75, 139.46, 128.85, 128.17, 127.95, 127.34, 122.82, 122.11, 116.69, 59.72, 59.01, 53.40, 53.37, 50.08, 48.46, 46.27, 39.14, 37.20, 31.43, 30.95, 28.46, 15.41. HRMS-MS/MS C34H41CIN6O2 + H+ calculated 601.30523, found 601.30477. Analytical HPLC: Agilent poroshell C-184.6 x 50 mm, 2.7 mm; gradient 10%-80% ACN in water + 0.1% TFA; 60 min run; injection 20 mL (1 mg/mL); temperature 40 C; Rt 32.832 min, purity >95% (at absorbance 1254 nm). Elemental analysis ( C34H41CIN6O2 + H2O) calculated C 65.95, H 7.00, N 13.57, found C 65.70, H 6.91, N 13.62.
Example 2. Radioligand Binding Studies: hD2R , hD3R , and hD4R
Radioligand binding assays were conducted similarly as previously described (Battiti et al. 2019; Michino et al). HEK293 cells stably expressing human D2LR or D3R or D4.4 were grown in a 50:50 mix of DMEM and Ham’s F12 culture media, supplemented with 20 mM HEPES, 2 mM L-glutamine, 0.1 mM non-essential amino acids, 1X antibiotic/antimycotic, 10% heat-inactivated fetal bovine serum, and 200 μg/mL hygromycin (Life Technologies, Grand Island, NY) and kept in an incubator at 37 °C and 5% CO2. Upon reaching 80-90% confluence, cells were harvested using premixed Earle’s balanced salt solution with 5 mM EDTA (Life Technologies) and centrifuged at 3000 rpm for 10 min at 21 °C. The supernatant was removed, and the pellet was resuspended in 10 mL hypotonic lysis buffer (5 mM MgCL, 5 mM Tris, pH 7.4 at 4 °C) and centrifuged at 14 500 rpm (~25000g) for 30 min at 4 °C. The pellet was then resuspended in binding buffer. Bradford protein assay (Bio-Rad, Hercules, CA) was used to determine the protein concentration. For [3H]-N-methylspiperone binding studies membranes were diluted to 500 μg/mL, in fresh EBSS binding buffer made from 8.7 g/L Earle’s Balanced Salts without phenol red (US Biological, Salem, MA), 2.2 g/L sodium bicarbonate, pH to 7.4, and stored in a -80 °C freezer for later use. For [3H]-(R)-(+)-7- OH- DPAT binding studies, membranes were harvested fresh; the binding buffer was made from 50 mM Tris, 10 mM MgCl2, 1 mM EDTA, pH 7.4. On the test day, each test compound was diluted into half-log serial dilutions using the 30% dimethyl sulfoxide (DMSO) vehicle.
When it was necessary to assist solubilization of the drugs at the highest tested concentration, 0.1% AcOH (final concentration v/v) was added alongside the vehicle. Membranes were diluted in fresh binding buffer. Radioligand competition experiments were conducted in 96- well plates containing 300 μL fresh binding buffer, 50 μL of the diluted test compound, 100 μL of membranes (for [3H]-N-methylspiperone assays: 10-20, 10-20, and 20-30 μg/well total protein for hD2LR, hD3R, and hD4.4R, respectively; for [3H]-(R)-(+)-7- OH-DPAT assays: 40-80, and 20-40 μg/well total protein for hD2LR, and hD3R, respectively), and 50 μL of radioligand diluted in binding buffer ( [3H]-N-methylspiperone : 0.4 nM final concentration for all the hD2-like receptor subtypes; [3H]-(R)-(+)-7-OH-DPAT: 1.5 nM final concentration for hD2L, and 0.5 nM final concentration for hD3; Perkin Elmer). Aliquots of radioligands solution were also quantified accurately in each experiment replicate, to determine how much radioactivity was added, taking in account the experimentally determined counter efficiency. Nonspecific binding was determined using 10 pM (+)- butaclamol (Sigma- Aldrich, St. Louis, MO), and total binding was determined with the 30% DMSO vehicle. All compound dilutions were tested in triplicate, and the reaction incubated for 60 min ([3H]-N-methylspiperone assays) or 90 min ([3H]-(R)-(+)-7-OH-DPAT assays) at RT. The reaction was terminated by filtration through PerkinElmer Uni-Filter-96 GF/B, presoaked for the incubation time in 0.5% polyethylenimine, using a Brandel 96-Well Plates Harvester Manifold (Brandel Instruments, Gaithersburg, MD). The filters were washed thrice with 3 mL (3 Å~ 1 mL/well) of ice-cold binding buffer. PerkinElmer MicroScint 20 Scintillation Cocktail (65 μL) was added to each well, and filters were counted using a PerkinElmer MicroBeta Microplate Counter. IC50 values for each compound were determined from dose-response curves, and Ki values were calculated using the Cheng-Prusoff equation (Cheng et al. “Relationship between the inhibition constant (Kl) and the concentration of inhibitor which causes 50 per cent inhibition (150) of an enzymatic reaction” Biochem Pharmacol 1973, 22 (23), 3099-108). Kd values were determined via separate homologous competitive binding experiments. When a complete inhibition could not be achieved at the highest tested concentrations, Ki values have been extrapolated by constraining the bottom of the dose-response curves (=0% residual specific binding) in the nonlinear regression analysis. These analyses were performed using GraphPad Prism version 8 for Macintosh (GraphPad Software, San Diego, CA). All results were rounded to the third significant figure. Ki values were determined from at least three independent experiments and are reported as the mean + standard error of the mean (SEM).
Example 3. Radioligand Binding Studies: hMOR
Radioligand binding experiments were conducted, and the results analyzed, as described in Example 2, and similarly as previously reported (Cai et al. “Opioid-galanin receptor heteromers mediate the dopaminergic effects of opioids” J Clin Invest 2019, 129 (7), 2730-2744). HEK293 cells stably expressing hMOR were grown in a DMEM medium, supplemented with 10% FBS, 2 mM L-glutamine, 1% penicillin-streptomycin (or antibiotic/antimycotic) and hygromycin B (50 μg/mL). Upon reaching confluence the cells were harvested and the membranes prepared as detailed before. The binding buffer was made of 50 mM Tris and 5 mM MgCl2 at pH 7.4. The experiments were performed in presence of [3H]-DAMGO (final concentration 3 nM; Perkin Elmer) and 30 μg/well of membranes (final concentration). The reactions were incubated for 60 min at RT and terminated by rapid filtration through Perkin Elmer Uni-Filter-96 GF/B, presoaked for 60 min in 0.5% polyethylenimine. The non-specific binding was determined using 10 μM C-TOP, cold DAMGO, or Naloxone. The radioligand Kd was measured via radioligand saturation experiments.
Binding Studies and Structure- Activity Relationships (SAR)
All the newly synthesized compounds were tested for their binding affinities at hMOR (in competition with [3H]-DAMGO), hD2R, hD3R, and hD4R (in competition with [3H]-N- methylspiperone ([3H]-NMSP) for all the hD2-like subtypes). Moreover, a subset of selected hits were further studied at hD2R and hD3R using the agonist [3H]-(R)-(+)-7-OH-DPAT as the competing radioisotope. It has previously been reported that differences in affinity due to the radioligand being an agonist or antagonist can predict functional efficacy profiles for the tested compounds (Battiti et al. 2019; Keck et al. “Dopamine D4 Receptor-Selective Compounds Reveal Structure- Activity Relationships that Engender Agonist Efficacy” J Med Chem 2019, 62 (7), 3722-3740).
In Table 1 the binding data are reported for the first series of MOR-D3R hybrid analogs, based on, 3-, 4-, and 6-like PPs. Reference compounds, including fentanyl, 3, 4, 5, and 6 are reported in the table for useful comparisons. Among the reference compounds, it was interesting to observe how 3, a well-known potent MOR agonist, despite presenting an SP identical to the D2-like antagonist 5 (FIG. 1), binds with low micromolar affinity to all the D2-like subtypes, as predicted in the CADD studies. Fentanyl, 4, and 6, all have low nanomolar affinities for MOR, as expected and consistent with the literature (Volpe et al.; Cai et ah). Fentanyl, however, presents moderate affinity for D4R ( Ki = 554 nM), while being inactive at both D2R and D3R (Ks >10,000 nM), meanwhile 6 is endowed with a preferential low micromolar affinity for D3R, being completely inactive at D2R and >10-fold selective over D4R. These data highlight how subtle structural changes in well-characterized MOR agonists, can induce different binding profiles and subtype selectivity for the D2-like dopamine receptors, and that binding affinities can be directed toward dual-target profiles with well-designed structural modifications.
In general, replacing the nitrile group with the 3-like N,N-dimethylamide synthon significantly increased the affinity profiles of all the analogs. In particular, 23 presents one of the highest MOR affinities among all the new analogs (MOR Ki = 0.832 nM), and despite the shorter linker, which is generally less favorable for Di-like receptors affinity, a potent D2-like ligand was still obtained (D2R Ki = 74.7 nM, D3R Ki = 171 nM, and D4R K = 102 nM). A similar nanomolar binding profile across D2R and D3R was also confirmed when 23 was tested in the presence of [3H]-(R)-(+)-7-OH-DPAT. The analogous nitrile compound, 13, showed reduced MOR binding (~320-fold; Ki = 266 nM) and reduced D3R binding (~ 13-fold; Ki = 2,240 nM).
Not wishing to be bound by theory, but perhaps because of this conformational change, N,N-dimethylamide to cyano substitutions on the extended linker molecules such as 14 (D2R Ki - 149 nM, D3R Ki - 132 nM) are better tolerated at D3R than the shorter linker compounds such as 13 (D2R Ki = 2630 nM, D3R Ki = 2240 nM). As in D3R, the extended linker compounds are reasonably well tolerated inside MOR. However, in contrast to its binding profile at D3R, even the extended linker molecule with nitrile substitutions 14 shows reduced MOR binding (K = 490 nM). This was also observed with the nitrile analogues, 35 and 37. Compound 28, an analogous compound with substituted N ,N-dimethylamide in the MOR PP motif, shows significant improvement in both D3R affinity (K = 39.2 nM) and a MOR binding (K = 23.8 nM). This analog in this series shows a low nanomolar dual-target affinity for both the MOR and the D2-like receptors. In contrast, compound 18 showed similarly high affinity for the D2-like receptors, but MOR affinity was diminished (Ki = 1470 nM). Whereas compounds 15, 19, 21, 24 and 27 showed the opposite profile, having higher affinities for MOR than D2R or D3R. Compounds 16 and 22 were poorly active at all receptors tested, reflecting an inability to bind the OBS of either MOR or the D2-like receptors.
Introduction of the hydroxy substituent in the butylamine linker (compounds 29 and 32), as well as replacement of the 2,3-dichlorophenyl piperazine, with the 2-chloro-3-ethyl- phenylpiperazine (compounds 31 and 32) either maintained or slightly decreased the overall affinity for all the D2-like receptor subtypes, when compared to 28. The introduction of l,2,3,4-tetrahydroisoquinoline-7-carbonitrile as D3R PP (34), decreased affinity for the D2- like receptors into the micromolar range. None of the diphenyl-pyrrolidine analogues (compounds 42, 43 and 46) were active. However, the only bivalent compound 46 did have moderate affinity for D3R (Ki = 288 nM).
Shifting from a phenylpiperazine-based D3R PP, to a highly decorated 8-based D3R PP, to develop SAR around the pyrrolidine scaffold, 40, containing a racemic pyrrolidin-2- ylmethyl- amide linker, and 48, presenting a butyl ether linker chain in position 4 of the trans- pyrrolidine nucleus were synthesized. Compound 48 showed the highest D2R/D3R affinity among all the new analogs (D2R Ki = 9.41 nM; D3R Ki = 2.21 nM), however the regio- and stereochemistry of the substituted pyrrolidine ring was detrimental for MOR binding, with a Ki of 559 nM. On the other hand, 40 emerged as a promising lead, alongside 23 and 28, with its almost identical affinities for both MOR (Ki = 106 nM) and D3R (Ki = 135 nM), ~4- and ~25-fold selectivity over D2R and D4R respectively. This profile distinguished 40 as one of the most promising dual-target MOR-D3R compounds in the series.
Across all the tested compounds, no significant differences were observed in the D2- like affinities determined using [3H]-NMSP and [3H]-(R)-(+)-7-OH-DPAT binding assays were observed, unlike previous observations for efficacious agonist ligands (Newman et al. 2020; Battiti et al. 2019), consistent with the hypothesis that all the new analogs are likely antagonists or low efficacy partial agonists at D3R.
Based on their binding profiles, a select group of hits were tested in functional assays, to determine their agonist and antagonist potencies for the multiple GPCR-related signaling pathways, as well as to validate and confirm the MOR agonism and D3R antagonism/partial agonism profile sought for these new hybrid molecules.
Figure imgf000076_0001
Figure imgf000077_0001
Figure imgf000078_0001
Figure imgf000079_0001
Figure imgf000080_0001
Figure imgf000081_0001
Figure imgf000082_0001
Radioligand competition binding affinity data, for all the MOR diphenyl PP analogs based on 3, 4, and 6 at hMOR and hD2-like receptor subtypes. All the affinity values are expressed as Ki ± SEM, derived from IC50 values using the Cheng-Prusoff equation, and calculated as the mean of at least three independent experiments (n = number of independent experiments), each performed in triplicate. ND = Not Determined. aNo inhibition of specific radioligand binding was observed at the highest tested concentration in one to three independent experiments, each performed in triplicate. bKi value obtained from reference (Volpe et al. “Uniform assessment and ranking of opioid mu receptor binding constants for selected opioid drugs” Regul Toxicol Pharmacol 2011, 59 (3), 385-90).
Table 1A
Figure imgf000084_0001
Radioligand competition binding affinity data. All the affinity values are expressed as Ki ± SEM, derived from IC50 values using the Cheng-Prusoff equation, and calculated as the mean of at least three independent experiments (n = number of independent experiments), each performed in triplicate. Multiparameter optimization (MPO) scores (Wager T. T. et al. “Moving beyond rules: the development of a central nervous system multiparameter optimization (CNS MPO) approach to enable alignment of druglike properties” ACS Chem. Neurosci. 1 (6) (2010) 435-449) have been calculated for predicting compound CNS penetrability based on cLogP, cLogD, molecular weight (M.W.), topological polar surface area (TPSA), hydrogen bond donors (HBD), and p/fa.
Example 4. Bioluminescence Resonance Energy Transfer (BRET) Studies
All reagents were purchased from Sigma Aldrich-Merck unless otherwise stated. BRET experiments were performed in transiently transfected human embryonic kidney 293 T (HEK 293T) cells, as described previously (Gillis et al.; Klein Herenbrink et al. “The role of kinetic context in apparent biased agonism at GPCRs” Nat Commun 2016, 7, 10842). Briefly, cells were grown and maintained at 37 °C in 5 % CO2 in Dulbecco’s modified eagle medium (DMEM) supplemented with 10 % (v/v) fetal bovine serum (FBS). Cells were seeded in 10 cm Petri dishes (2.5 x 106 cells per dish) and allowed to grow overnight in media at 37 °C, 5 % CO2. The following day, cells were transiently transfected in media supplemented with antibiotics (100 U/mL penicillin and 100 m g/mL streptomycin, Gibco) using a 1:6 total DNA to PEI (PolySciences Inc) ratio. BRET constructs were as follows: 4 of Ngb33-Venus and 1 μg of mMOR-Rluc8 for Nb33 recruitment, 2 o μfg WT-Gα (i2 or oA), 1 μg of Gβ 1 - Venus(156-239), 1 μg of Gγ2- Venus( 1- 155), 1 μg of masGRK3ct-Rluc8 and 1 of receptor (SNAP-mMOR or hD3R) for GPA (Hollins et al. “The c-terminus of GRK3 indicates rapid dissociation of G protein heterotrimers” Cell Signal 2009, 21 (6), 1015-21) and 4 ug of arrestin-3-Venus, 2 μg of WT-GRK2 and 1 μg of mMOR-Rluc8 for arrestin-3 recruitment. Cells were then allowed to grow overnight at 37 °C, 5 % CO2. The next day, cells were plated in Greiner poly-D-lysine-coated 96-well plates (SLS) in media and allowed to grow overnight. On the day of the assay (48h post-transfection), cells were washed once with D- PBS (Lonza, SLS) and incubated in D-PBS for 30 min at 37 °C. For the antagonist-mode assays that require pre-incubation, the cells were washed once with D-PBS and incubated with ligands in D-PBS (supplemented with 10 mM glucose) at 37 °C, 5 % CO2 for 3h prior to starting the assay. The Rluc substrate coelenterazine h (NanoLight) was added to each well (final concentration of 5 pM) and cells were incubated for 5 minutes at 37 °C. After 5 minutes, ligands (final concentration from 10 pM to 1 nM in D-PBS) were added to the plate and cells were incubated for a further 10 minutes at 37 °C before reading the plate in a PHERAstar FSX microplate reader (Venus and Rluc emission signals at 535 and 475 nm respectively, BMG Labtech). The ratio of Venus:Rluc counts was used to quantify the BRET signal in each well. Data were normalized to the wells containing 10 pM DAMGO/quinpirole or no drug for maximal or minimal response, respectively and as indicated in the figure legends. All experiments were performed in duplicate and at least three times independently. All data points represent the mean and error bars represent the standard error of the mean (SEM) and were fitted using the built-in log(agonist) vs. response (three parameters) model in Prism 8.0 (GraphPad software Inc., San Diego, CA). For agonist-mode assays data was fitted to a three parameter concentration-response model where EC50 is the concentration of the agonist needed to elicit half the maximal response of the particular agonist, defined as Emax. For the antagonist-mode assays, data points were fitted using a three-parameter concentration-response model where IC50 is the concentration required to inhibit half the maximum response of the agonist used at a particular concentration. Values of pEC50 or pIC50 plus/minus error are given as the error has a gaussian distribution whereas the error associated with the antilog value does not. For some ligands for which the lower asymptote of the curve was not well defined within the concentration range the bottom was constrained to be equal to 0%. BRET functional studies at MOR and D3R were conducted to characterize the action of selected ligands to signal through both MOR and D3R; these results are shown in Table 2. The action of these ligands was assessed through arrestin-3 (or β-arrestin-2) recruitment at MOR and G protein activation (GPA) at MOR (Gαi2) and D3R (GαoA) assays. In addition, the ability of the ligands to induce the active state of the MOR was determined by measuring recruitment of a conformationally selective nanobody that recognizes and binds to the active conformation of MOR, nanobody 33 (Nb33) (Sounier et al. “Propagation of conformational changes during mu-opioid receptor activation” Nature 2015, 524 (7565), 375-8). Four of the newly synthesized MOR-D3R hybrids (14, 23, 28, 40) were tested. The efficacious agonists DAMGO (D-Ala2, N-MePhe4, Gly5-ol-enkephalin), quinpirole and dopamine were used as reference agonists to normalize data at the MOR and D3R, respectively. MOR partial agonist morphine was included to illustrate the relative coupling efficiency and amplification of the different assays. Both known antagonists, naloxone (MOR) and 5 (D3R), inhibited agonist- stimulated GPA in a concentration-dependent manner.
All four MOR diphenyl PP analogs tested (14, 23, 28 and 40), showed agonist activity at MOR, with 23 being the most potent and efficacious compound. Compound 14 showed low potency MOR agonism that could only be detected at the highest concentration used of 10 mM in the most amplified and sensitive GPA i2 assay. 40 displayed higher potency and efficacy in assays of MOR activation than 28, with 28 displaying no detectable agonism in the less amplified Nb33 and arrestin-3 recruitment assays, but an Emax of 50% that of DAMGO in the GPA i2 assay. Compound 40 gave a robust response (Emax = 84.4% of DAMGO) in the GPA i2 assay but much weaker responses in the arrestin and Nb33 assays, indicating it is a less efficacious partial agonist than morphine. All four bivalent compounds share a similar MOR diphenyl PP based on 3 and 4, the N,N-dimethyl-diphenylbutanamide PP being more favorable than the diphenylbutanenitrile PP for MOR agonism. The major structural differences are present in the D3R PP as well as the type and length of the linker between the two pharmacophores: a shorter linker being more favorable for MOR agonism.
In general, across the series of compounds and morphine it was observed higher maximal effects (Emax) and potencies in the GPA i2 assay as compared to that in the arrestin-3 recruitment and Nb33 assays. Such behavior is consistent with the action of partial agonists at signaling endpoints with different levels of amplification and coupling efficiency of the pathway. In agreement with this, when these data were analyzed using the Black and Leff operational model of agonism and assessed for biased agonism using DAMGO as the reference ligand, none of the compounds displayed significant bias between these two pathways relative to the action of DAMGO (Table 3). When these four MOR diphenyl PP ligands were tested for their ability to activate the D3R, 14 and 28 showed similar efficacies (64% and 55% of dopamine, respectively), with 28 being the most potent compound in agreement with their relative affinities (Table 1). Although 14 and 40 display similar affinities for D3R, 40 acted as an antagonist with micromolar potency (IC50 = 1.5mM), whereas 14 acted as a robust partial agonist ( Emax = 63.8% of quinpirole). Lastly, 23, which was the most potent MOR agonist and shares the same D3R PP structure as 28 but with a shorter linker, displayed weak partial agonism (Emax = 20% of quinpirole) at the D3R and sub-micromolar potency consistent with its binding affinity.
Table 2.
Figure imgf000088_0001
Figure imgf000089_0001
Potencies and efficacies at MOR and D3R. All data represent the mean of at least three independent experiments (n = number of independent experiments), each performed in duplicate. Potency values are expressed as pEC50 ± SEM with the corresponding EC50 in nM in brackets. Efficacy values are calculated as a percentage of a reference ligand (DAMGO or quinpirole for MOR and D3R respectively) and expressed as Emax ± SEM (%). NA = Not Active, the compound presents no agonist activity at the highest tested concentration.
Table 3.
Figure imgf000090_0001
Biased agonism analysis for MOR signaling pathways. All data represent the mean of at least three independent experiments, each performed in duplicate. Transduction coefficients and bias factors were calculated using the Black and Leff operational model of agonism using DAMGO as the reference, balanced ligand. To perform the bias analysis, each individual concentration-response curve was fitted to the following form of the operational model of agonism (Black et al. “An operational model of pharmacological agonism: the effect of E/[A] curve shape on agonist dissociation constant estimation” Br J Pharmacol 1985, 84 (2), 561-71) to allow the quantification of biased agonism:
Figure imgf000091_0001
in which Em is the maximal possible response of the system, basal is the basal level of response, [A] is the molar concentration of each agonist, K represents the equilibrium dissociation constant of the agonist and τ is an index of the signaling efficacy of the agonist that is defined as RT/KE, where RT is the total number of receptors and Kr is the coupling efficiency of each agonist-occupied receptor, and n is the slope of the transducer function that links occupancy to response. The analysis assumes that the transduction machinery used for a given cellular pathway are the same f all agonists, such that the Em and transducer slope (n) are shared between agonists. Data for all ligands for each pathway were fitted globally, to determine values of KA and t. Biased agonism was quantified as previously described (Kenakin et al. “A simple method for quantifying function selectivity and agonist bias” ACS Chem Neurosci 2012, 3 (3), 193-203). In short, to exclude the impact of cell-dependent and assay-dependent effects on the observed agonism at each pathway, the log(τ/KA) value of a reference agonist, in this case DAMGO, is subtracted from the log(τ/KA) value of the other ligands to yield Δlog(τ/KA .) The relative bias can then be calculated for each ligand at the two different signaling pathways by subtracting the Δlog(τ/KA) of one pathway from the other to give a ΔΔ log(τ/KA) value, which is a measure of bias. A lack of biased agonism will result in values of ΔΔlog(τ/kA) not significantly different from 0 between pathways. To account for the propagation of error associated with the determination of composite parameters, the following equation was used:
Figure imgf000091_0002
where pooled_SEM is the calculated error for the difference and SEj1 and SEj2 is the individual uncorrelated/random error values used to propag the pooled SEM value.
The data obtained highlight a series of hit to lead candidates as MOR-D3R dual-target ligands. Multiple combinations of bivalent or bitopic ligands were synthesized based on carefully designed structural modifications and in silico guided SAR around the MOR PP, D3R PP and SP, as well as linkers, with a particular focus on regio- and stereochemistry. Compounds were identified with a range of sub-nanomolar to sub-micromolar binding affinities for each receptor of interest and thus provide a new approach to modulate the pharmacological profiles of highly selective MOR agonists through concomitant dual-target D3R antagonism.
The functional studies revealed three lead analogs, 23, 28 and 40, which are partial agonists at MOR and partial agonists or antagonists at D3R. Not wishing to be bound by theory, but it has been suggested that low intrinsic efficacy could explain the improved therapeutic window observed on the most recent MOR agonists, such as PZM21 and TRV- 130 (Gillis et al.) and compounds 23, 28 and 40 fit this desired functional profile with the added feature of D3R weak partial agonism or antagonism, which may prove beneficial in avoiding the addictive liability of opioid receptor targeted drugs. Compounds 23, 28 and 40 have central nervous system multiparameter optimization (MPO) (Wager, et al. “Moving beyond rules: the development of a central nervous system multiparameter optimization (CNS MPO) approach to enable alignment of dmglike properties” ACS Chem Neurosci 2010, 1 (6), 435-49; Wager et al. “Central Nervous System Multiparameter Optimization Desirability: Application in Drug Discovery” ACS Chem Neurosci 2016, 7 (6), 767-75) scores of ~2 and are predicted to be peripherally limited.
Example 5. Nociceptive and Locomotor Tests
Intracerebroventricular (i.c.v.) microinjection: Male adult (25-30 g) wild- type mice with C57BL/6J genetic backgrounds, purchased from Jaxson’s Laboratory, were individually housed and maintained on a 12-h light/dark cycle with free access to food and water. Under ketamine + xylazine anesthesia (100 mg/kg + 10 mg/kg, i.p.), mouse was implanted with a 30-gauge stainless steel guide cannula unilaterally into a lateral ventricle (coordinates: +0.3 mm posterior to bregma, 1.0 mm lateral to midline, and -3.0 mm ventral to the surface of the cortex). After 5-7 days of recovery from surgery the experiments began. A total of 36 mice were subdivided into 4 groups: compound 28 analgesia group (n = 10), morphine/loperamide analgesia group (n= 10), compound 28 locomotion group ( n = 8), and intranasal compound 28 analgesia group (n=8). Each animal received 2-3 drug injections during the experiments with 3-5 days of time intervals. The order of drug injections was counterbalanced. Hot-plate test: Nociceptive tests were be performed using a hot plate device (Model 39, IITC Life Science Inc., Woodland Hills, CA, USA). See FIGS. 2, 4, 5. Briefly, mice were placed inside a transparent cage on the hot plate, which was pre-heated to 52 (±0.2) °C. When thermal nociceptive signs such as licking, stomping the hind paw, or jumping from the plate appeared, the mouse was immediately removed from the cage. The time interval (sec) from mouse being placed on the hotplate to exhibiting the first sign of thermal nociception was measured. The cut-off time for the test was 60 s to avoid tissue damage. Each animal was be tested 2~3 times for three different drug doses with time intervals of 3~5 days.
Open-field locomotion: This experiment was designed to study the effects of i.c.v. or i.p. injection of morphine, compound 28 or loperamide on open-field locomotor behavior in mice. See FIG. 3. Before locomotor testing, mice were habituated to locomotor detection chambers (Accuscan Instruments, Columbus, OH, USA) for 2~3 days (3 hours per day). On the test day, mice were placed in the chamber for 1 h of habituation (baseline), and then each animal received one dose of morphine, compound 28 or vehicle (saline, i.c.v.). Next, mice were placed back in the open-field apparatus and locomotor activity was measured over a 2 h period. The order of the injections was counterbalanced. The time intervals between the drug tests were 3-5 days. The distance traveled before and after injections was collected in 10-min intervals using the VersaMax data analysis system (Accuscan Instruments).
The above work shows the use of bivalent drug design to engage both MOR and D3R in the pursuit of a novel class of opioid analgesics with lower abuse potential.
The terms “a” and “an” do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The term “or” means “and/or”. Reference throughout the specification to “one embodiment”, “another embodiment”, “an embodiment”, and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity).
In general, the compositions, methods, or formulae may alternatively comprise, consist of, or consist essentially of, any appropriate components or steps herein disclosed.
The invention may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants, species, or steps used in the prior art compositions, methods, or formulae, or that are otherwise not necessary to the achievement of the function and/or objectives of the present claims.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
The endpoints of all ranges directed to the same component or property are inclusive of the endpoints, are independently combinable, and include all intermediate points and ranges (e.g., ranges of “up to about 25 wt.%, or, more specifically, about 5 wt.% to about 20 wt.%,” is inclusive of the endpoints and all intermediate values of the ranges of “about 5 wt.% to about 25 wt.%,” such as about 10 wt% to about 23 wt%, etc.).
All methods described herein can be performed in a suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”), is intended merely to better illustrate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention as used herein. Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this invention belongs.
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

What is claimed is:
1. A compound according to Formula (I):
Figure imgf000095_0001
Formula (I) or a pharmaceutically acceptable salt thereof, wherein
Rx is CN or -(C=O)-N(Rz)2 wherein each instance of Rz independently is hydrogen, C1- C6 alkyl, C1-C6 haloalkyl, or C2-C6 alkanoyl; each instance of Ra independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; each instance of n independently is 0, 1, 2, or 3;
Y1 is -NH- or a piperazinyl group attached to the core structure and L1 through the nitrogen atoms;
L1 is a covalent bond or a linking group;
Y2 is a covalent bond or a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms;
L2 is a covalent bond or a linking group; and
Ar1 is an aryl or a heteroaryl, wherein when Ar1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents.
2. The compound of claim 1, wherein Rx is -(C=O)-N(Rz)2 wherein each instance of Rz independently is C1-C6 alkyl.
3. The compound of any one of claims 1-2, wherein each instance of n independently is 0 or 1.
4. The compound of any one of claims 1-3, wherein Ar1 is substituted phenyl or optionally substituted pyridyl.
5. The compound of any one of claims 1-3, wherein Ar1 is
Figure imgf000096_0001
wherein a is 1 or 2, and each instance of R1, R2, R3, and R4 independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy, hydroxyl, or halogen with the proviso that at least two of R1, R2, R3, and R4 are other than hydrogen.
6. The compound of claim 5, wherein: a) R1 and R4 are hydrogen and R2 and R3 are halogen; b) R1 and R4 are hydrogen, R2 is halogen, and R3 is C1-C6 alkyl; c) R1 is hydrogen or hydroxyl, R2 is C1-C3 alkoxy, R3 is halogen, and R4 is C1-C6 alkyl; d) R5 is trifluoromethyl; or e) R6 is ethyl and a is 1.
7. The compound of any one of claims 1-6, wherein Y1 is piperazinyl group and L1-Y2-L2 is a covalent bond so that Y1-Ar1.
8. The compound of any one of claims 1-6, wherein:
Y1 is -NH-;
L1 is a linking group, wherein L1 linking group is an alkyl chain containing 1, 2, 3, 4, 5,
6, 7, 8, 9 or more carbon atoms in the chain, optionally including internal unsaturation, optionally an internal cycloalky group, optionally an internal heteroatom, optionally a substitution on the alkyl chain, and optionally wherein L1 is linked to Y2 via a heteroatom;
Y2 is a 5-6-membered heterocyclic group comprising 1 or 2 nitrogen atoms; and L2 is a linking group, wherein L2 linking group is an alkyl chain containing 1, 2, 3, 4, 5,
6, 7, 8, 9 or more carbon atoms in the chain, wherein the alkyl chain is linked to Ar1 through a covalent bond, O, S, NRy, -(C=O)-, C(RW)2, N(Ry)-(C=O)-, -(C=O)-N(Ry), -O- (C=O)-O-, -O-(C=O)-N(Ry)-, -N(Ry)-(C=O)-O-, or -N(Ry)-(C=O)-N(Ry)-; each instance of Ry independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, or Ci-Ce alkanoyl; and each instance of Rw independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino.
9. The compound of any one of claims 1-6, wherein:
Y1 is -NH-;
L1 is a linking group, wherein L1 linking group is -(CH2)g wherein g is 2, 3, 4, 5, 6, 7, or 8; -(CH2)f-CH=CH-(CH2)f- wherein each instance of f independently is 1, 2, or 3; or
Figure imgf000097_0002
wherein each instance of f independently is 1, 2, or 3; optionally wherein L1 is linked to Y2 via O;
Y2 is a pyrrolidinyl or piperazinyl group;
L2 is a linking group, wherein L2 linking group is an alkyl chain containing 1 or 2 carbon atoms wherein the alkyl chain is linked to Ar1 through N(Ry)-(C=O)- or -(C=O)-N(Ry); and each instance of Ry independently is hydrogen or C1-C6 alkyl.
10. The compound of any one of claims 1-6, wherein the dual-target compound is according to Formula (IA):
Figure imgf000097_0001
Formula (IA) or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I);
Z is N or CH; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
11. The compound of any one of claims 1-6, wherein the dual-target compound is according to Formula (IB):
Figure imgf000098_0001
or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I); each instance of Rc and Rd independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C3-C6 cycloalkyl, or a C3-C6 cycloalkenyl;
Z is N or CH; each instance of Rb independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
12. The compound of any one of claims 1-6, wherein the dual-target compound is according to Formula (IC):
Figure imgf000098_0002
Formula (IC) or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I); each instance of Rc and Rd independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C3-C6 cycloalkyl, or a C3-C6 cycloalkenyl; x is 1 or 2; Z is N or CH; each instance of Rb independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
13. The compound of any one of claims 1-6, wherein the dual-target compound is according to Formula (ID):
Figure imgf000099_0001
or a pharmaceutically acceptable salt thereof, wherein each instance of Ra, n, and Rx are as defined above for Formula (I); each instance of Rc and Rd independently is hydrogen, hydroxyl, or halogen; m is 0, 1, 2, 3, or 4; t is 0, 1, 2, 3, or 4; is a single bond, a double bond, a C3-C6 cycloalkyl, or a C3-C6 cycloalkenyl; x is 1 or 2;
Z is N or CH; each instance of Rb independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; q is 0, 1, 2, 3 or 4 when Z is N; and q is 2, 3, or 4 when Z is CH.
4. A compound of formula (X):
Figure imgf000100_0001
wherein Rx is CN or -(C=O)-N( Rz)2 wherein each instance of Rz independently is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, or C2-C6 alkanoyl; each instance of Ra independently is C1-C6 alkyl, C1-C6 haloalkyl, halogen, hydroxyl, amino, nitro, cyano, -COOH, -CHO, -CONH2, C1-C6 alkoxy, C1-C6 haloalkoxy, C2-C6 alkanoyl, mono-C1-C2 alkylamino, or di-C1-C2 alkylamino; each instance of n independently is 0, 1, 2, or 3;
Re is -C(O)NHRf; or a C1 to C4 alkyl group substituted by
Figure imgf000100_0002
wherein Ar1 is aryl or a heteroaryl; wherein when Ar1 is phenyl, the phenyl is substituted by 2, 3, or 4 substituents;
Rs is H or CH3; and Rt is H or OH;
Rf is a C1 to C4 alkyl group substituted by
Figure imgf000100_0003
h is 1 or 2; Rt is H or OH; or a salt thereof.
15. A compound of formula (XI)
Figure imgf000101_0001
wherein Ra, Rf, Rx, and n are defined as in claim 14; or a salt thereof.
16. A pharmaceutical composition comprising a dual- target compound of any one of claims 1-15 and optionally a pharmaceutically acceptable carrier.
17. A method of treating pain, comprising providing to a patient in need thereof a therapeutically effective amount a dual-target compound or composition of any one of claims 1-15.
18. The method of claim 17, wherein the pain is chronic pain, acute pain, breakthrough pain, post-operative pain, perioperative pain, mild pain, moderate pain, severe pain, bone and joint pain, soft tissue pain, nerve pain, pain due to a disease or disorder, pain due to trauma, neuropathic pain, nociceptive pain, radicular pain, or a combination thereof.
19. A method of treating a disease or disorder that is treatable by the action of a dopamine D3 receptor antagonist, a dopamine D3 receptor partial agonist, a MOR agonist, a MOR partial agonist, or a combination of one or more of the foregoing, comprising providing to a patient in need thereof a therapeutically effective amount of a dual-target compound or composition of any one of claims 1-15.
20. The method of claim 19 wherein the disorder is opioid use disorder and/or substance use disorder.
21. The compound according to claim 14 wherein Rs is H and n is 1
22. The compound according to claim 14 wherein Re is -C(O)NHRf.
23. The compound of claim 1, wherein the compound is compound 13, 14, 15, 23, 28, 30, 31, 32, 40, or 48, as set out in Table 1, or a pharmaceutically acceptable salt thereof.
24. The compound of claim 14 wherein the compound is compound 74, 75, or 84 as hereinbefore described, or a pharmaceutically acceptable salt thereof.
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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2140862A1 (en) * 1970-08-17 1972-03-02 The Upjohn Co., Kalamazoo, Mich. (V.St.A.) Preparations for repelling animals, in particular birds and mice
JPS5029578A (en) * 1973-07-11 1975-03-25
JPH0920759A (en) * 1995-07-06 1997-01-21 Kyorin Pharmaceut Co Ltd New cyclic diamine derivative and its production
JPH0920758A (en) * 1995-07-06 1997-01-21 Kyorin Pharmaceut Co Ltd New cyclic diamine derivative and its production
WO1997045115A1 (en) * 1996-05-31 1997-12-04 Trophix Pharmaceuticals, Inc. Pharmaceutical for treatment of neurological and neuropsychiatric disorders
EP1325912A1 (en) * 2000-10-12 2003-07-09 SSP Co., Ltd. 2,2-diphenylbutanamide derivatives and medicines containing the same
WO2005085226A1 (en) * 2004-03-10 2005-09-15 Janssen Pharmaceutica N.V. Mtp inhibiting aryl piperidines or piperazines substituted with 5-membered heterocycles
WO2006040646A1 (en) * 2004-10-14 2006-04-20 Pfizer, Inc. Benzimidazole or indole amides as inhibitors of pin1
JP2007055940A (en) * 2005-08-24 2007-03-08 Astellas Pharma Inc Pyrazolopyrimidine derivative
WO2015092009A1 (en) * 2013-12-20 2015-06-25 Laboratorios Del Dr. Esteve, S.A. Piperazine derivatives having multimodal activity against pain

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2140862A1 (en) * 1970-08-17 1972-03-02 The Upjohn Co., Kalamazoo, Mich. (V.St.A.) Preparations for repelling animals, in particular birds and mice
JPS5029578A (en) * 1973-07-11 1975-03-25
JPH0920759A (en) * 1995-07-06 1997-01-21 Kyorin Pharmaceut Co Ltd New cyclic diamine derivative and its production
JPH0920758A (en) * 1995-07-06 1997-01-21 Kyorin Pharmaceut Co Ltd New cyclic diamine derivative and its production
WO1997045115A1 (en) * 1996-05-31 1997-12-04 Trophix Pharmaceuticals, Inc. Pharmaceutical for treatment of neurological and neuropsychiatric disorders
EP1325912A1 (en) * 2000-10-12 2003-07-09 SSP Co., Ltd. 2,2-diphenylbutanamide derivatives and medicines containing the same
WO2005085226A1 (en) * 2004-03-10 2005-09-15 Janssen Pharmaceutica N.V. Mtp inhibiting aryl piperidines or piperazines substituted with 5-membered heterocycles
WO2006040646A1 (en) * 2004-10-14 2006-04-20 Pfizer, Inc. Benzimidazole or indole amides as inhibitors of pin1
JP2007055940A (en) * 2005-08-24 2007-03-08 Astellas Pharma Inc Pyrazolopyrimidine derivative
WO2015092009A1 (en) * 2013-12-20 2015-06-25 Laboratorios Del Dr. Esteve, S.A. Piperazine derivatives having multimodal activity against pain

Non-Patent Citations (61)

* Cited by examiner, † Cited by third party
Title
ALTARIFI ET AL.: "Effects of acute and repeated treatment with the biased mu opioid receptor agonist TRV 130 (oliceridine) on measures of antinociception, gastrointestinal function, and abuse liability in rodents", J PSYCHOPHARMACOL, vol. 31, no. 6, 2017, pages 730 - 739
AUSTIN ZAMARRIPA ET AL.: "The G-protein biased mu-opioid agonist, TRV130, produces reinforcing and antinociceptive effects that are comparable to oxycodone in rats", DRUG ALCOHOL DEPEND, vol. 192, 2018, pages 158 - 162, XP085519442, DOI: 10.1016/j.drugalcdep.2018.08.002
BIOORG MED CHEM LETT, vol. 13, no. 13, 7 July 2003 (2003-07-07), pages 2179 - 83
BOSSERT ET AL.: "Role of mu, but not delta or kappa, opioid receptors in context-induced reinstatement of oxycodone seeking", EUR J NEUROSCI, vol. 50, no. 3, 2019, pages 2075 - 2085
BRYAN M C ET AL: "High-throughput identification of fucosyltransferase inhibitors using carbohydrate microarrays", BIOORGANIC & MEDICINAL CHEMISTRY LETTERS, ELSEVIER, AMSTERDAM, NL, vol. 14, no. 12, 21 June 2004 (2004-06-21), pages 3185 - 3188, XP004841371, ISSN: 0960-894X, DOI: 10.1016/J.BMCL.2004.04.001 *
CAI ET AL.: "Opioid-galanin receptor heteromers mediate the dopaminergic effects of opioids", J CLIN INVEST, vol. 129, no. 7, 2019, pages 2730 - 2744
CARLSON ET AL.: "Predictors of transition to heroin use among initially non-opioid dependent illicit pharmaceutical opioid users: A natural history study", DRUG ALCOHOL DEPEND, vol. 160, 2016, pages 127 - 34, XP029437492, DOI: 10.1016/j.drugalcdep.2015.12.026
CHEMICAL LIBRARY: "3-cyano/amido-3,3,diphenylpropyl-1-piperazinyl derivatives; 2001-2015", 25 June 2015 (2015-06-25), pages 1 - 9, XP055933668, Retrieved from the Internet <URL:www.stn.org> [retrieved on 20220621] *
CHEMSPIDER: "benzenacetamide derivative", REGISTRY, 9 June 2008 (2008-06-09), pages 1 - 1, XP055917411, Retrieved from the Internet <URL:www.ston.org> [retrieved on 20220503] *
CHENG ET AL.: "Relationship between the inhibition constant (Kl) and the concentration of inhibitor which causes 50 per cent inhibition (150) of an enzymatic reaction", BIOCHEM PHARMACOL, vol. 22, no. 23, 1973, pages 3099 - 108, XP000942582, DOI: 10.1016/0006-2952(73)90196-2
CHIEN ET AL.: "Structure of the human dopamine D receptor in complex with a D /D selective antagonist", SCIENCE, vol. 330, no. 6007, 2010, pages 1091 - 5, XP055049168, DOI: 10.1126/science.1197410
CICERO ET AL.: "The changing face of heroin use in the United States: a retrospective analysis of the past 50 years", JAMA PSYCHIATRY, vol. 71, no. 7, 2014, pages 821 - 6
DE PAULIS ET AL.: "Synthesis, crystal structure and anti-dopaminergic properties of eticlopride (FLB 131", EUR. J. MED. CHEM., vol. 20, no. 3, 1985, pages 1418 - 279
DRAPER-JOYCE ET AL.: "The action of a negative allosteric modulator at the dopamine D2 receptor is dependent upon sodium ions", SCI REP, vol. 8, no. 1, 2018, pages 1208
GALLIGAN ET AL.: "Molecular physiology of enteric opioid receptors", AM J GASTROENTEROL SUPPL, vol. 2, no. 1, 2014, pages 17 - 21
GEYER MARCEL ET AL: "Can Silicon Make an Excellent Drug Even Better? An in vitro and in vivo Head-to-Head Comparison between Loperamide and Its Silicon Analogue Sila-Loperamide", CHEMMEDCHEM COMMUNICATIONS, vol. 10, no. 5, 20 March 2015 (2015-03-20), DE, pages 911 - 924, XP055917410, ISSN: 1860-7179, DOI: 10.1002/cmdc.201500040 *
GILLIS ET AL.: "Low intrinsic efficacy for G protein activation can explain the improved side effect profiles of new opioid agonists", SCI SIGNAL, vol. 13, no. 625, 2020
GOLDBERG ET AL.: "Stereochemical basis for a unified structure activity theory of aromatic and heterocyclic rings in selected opioids and opioid peptides", PERSPECT MEDICIN CHEM, vol. 4, 2010, pages 1 - 10
GRIM ET AL.: "A G protein signaling-biased agonist at the mu-opioid receptor reverses morphine tolerance while preventing morphine withdrawal", NEUROPSYCHOPHARMACOLOGY, vol. 45, no. 2, 2020, pages 416 - 425, XP036954052, DOI: 10.1038/s41386-019-0491-8
GRIM ET AL.: "Toward Directing Opioid Receptor Signaling to Refine Opioid Therapeutics", BIOL PSYCHIATRY, vol. 87, no. 1, 2020, pages 15 - 21, XP085932374, DOI: 10.1016/j.biopsych.2019.10.020
HOLLINS ET AL.: "The c-terminus of GRK3 indicates rapid dissociation of G protein heterotrimers", CELL SIGNAL, vol. 21, no. 6, 2009, pages 1015 - 21, XP026072428, DOI: 10.1016/j.cellsig.2009.02.017
IMAM ET AL.: "Intracerebroventricular administration of CYX-6, a potent mu-opioid receptor agonist, a delta- and kappa-opioid receptor antagonist and a biased ligand at mu, delta & kappa-opioid receptors, evokes antinociception with minimal constipation and respiratory depression in rats in contrast to morphine", EUR J PHARMACOL, vol. 871, 2020, pages 172918
IMAM ET AL.: "Progress in understanding mechanisms of opioid-induced gastrointestinal adverse effects and respiratory depression", NEUROPHARMACOLOGY, vol. 131, 2018, pages 238 - 255, XP085351338, DOI: 10.1016/j.neuropharm.2017.12.032
J MED CHEM., vol. 59, no. 16, 25 August 2016 (2016-08-25), pages 7634 - 50
JORDAN CHLOE J ET AL: "The highly selective dopamine D3R antagonist, R-VK4-40 attenuates oxycodone reward and augments analgesia in rodents", NEUROPHARMACOLOGY, ELSEVIER, AMSTERDAM, NL, vol. 158, 8 April 2019 (2019-04-08), XP085814756, ISSN: 0028-3908, [retrieved on 20190408], DOI: 10.1016/J.NEUROPHARM.2019.04.003 *
JORDAN ET AL., J PHARMACOL EXP THER, 2019
JORDAN ET AL., NEUROPHARMACOLOGY, 2019
JORDAN ET AL.: "Newly Developed Dopamine D3 Receptor Antagonists, R-VK4-40 and R-VK4-116, Do Not Potentiate Cardiovascular Effects of Cocaine or Oxycodone in Rats", J PHARMACOL EXP THER, vol. 371, no. 3, 2019, pages 602 - 614
JORDAN ET AL.: "The highly selective dopamine D R antagonist, R-VK4-40 attenuates oxycodone reward and augments analgesia in rodents", NEUROPHARMACOLOGY, vol. 158, 2019, pages 107597, XP085814756, DOI: 10.1016/j.neuropharm.2019.04.003
JULIE ET AL.: "Opioid pharmacology under the microscope", MOL PHARMACOL, 2020
KAYE ET AL.: "Prescription Opioid Abuse in Chronic Pain: An Updated Review of Opioid Abuse Predictors and Strategies to Curb Opioid Abuse: Part 1", PAIN PHYSICIAN, vol. 20, no. 2S, 2017, pages S93 - S109
KECK ET AL.: "Dopamine D4 Receptor-Selective Compounds Reveal Structure-Activity Relationships that Engender Agonist Efficacy", J MED CHEM, vol. 62, no. 7, 2019, pages 3722 - 3740
KENNEDY ET AL.: "Optimization of a Series of Mu Opioid Receptor (MOR) Agonists with High G Protein Signaling Bias", J MED CHEM, vol. 61, no. 19, 2018, pages 8895 - 8907
KLEIN HERENBRINK ET AL.: "The role of kinetic context in apparent biased agonism at GPCRs", NAT COMMUN, vol. 7, 2016, pages 10842
KLIEWER ET AL.: "Morphine-induced respiratory depression is independent of beta-arrestin2 signalling", BR J PHARMACOL, 2020
KLIEWER ET AL.: "Phosphorylation-deficient G-protein-biased mu-opioid receptors improve analgesia and diminish tolerance but worsen opioid side effects", NAT COMMUN, vol. 10, no. 1, 2019, pages 367
KOMOTO T ET AL: "NEW MU-OPIOID RECEPTOR AGONISTS WITH PIPERAZINE MOIETY", CHEMICAL AND PHARMACEUTICAL BULLETIN, PHARMACEUTICAL SOCIETY OF JAPAN, JP, vol. 49, no. 10, 1 January 2001 (2001-01-01), pages 1314 - 1320, XP001180116, ISSN: 0009-2363, DOI: 10.1248/CPB.49.1314 *
KOPINATHAN ET AL.: "Subtle Modifications to the Indole-2-carboxamide Motif of the Negative Allosteric Modulator N-(( trans)-4-(2-(7-Cyano-3,4-dihydroisoquinolin-2(l H)-yl)ethyl)cyclohexyl)-l H-indole-2-carboxamide (SB269652) Yield Dramatic Changes in Pharmacological Activity at the Dopamine D2 Receptor", J MED CHEM, vol. 62, no. 1, 2019, pages 371 - 377
KUMAR ET AL.: "Highly Selective Dopamine D Receptor (D R) Antagonists and Partial Agonists Based on Eticlopride and the D R Crystal Structure: New Leads for Opioid Dependence Treatment", J MED CHEM, vol. 59, no. 16, 2016, pages 7634 - 50, XP055370771, DOI: 10.1021/acs.jmedchem.6b00860
KUMAR ET AL.: "Synthesis and Pharmacological Characterization of Novel trans-Cyclopropylmethyl-Linked Bivalent Ligands That Exhibit Selectivity and Allosteric Pharmacology at the Dopamine D Receptor (D R", J MED CHEM, vol. 60, no. 4, 2017, pages 1478 - 1494
LEVITT ET AL.: "mu opioid receptor activation hyperpolarizes respiratory-controlling Kolliker-Fuse neurons and suppresses post-inspiratory drive", J PHYSIOL, vol. 593, no. 19, 2015, pages 4453 - 69
MONTANDON ET AL.: "G-protein-gated Inwardly Rectifying Potassium Channels Modulate Respiratory Depression by Opioids", ANESTHESIOLOGY, vol. 124, no. 3, 2016, pages 641 - 50, XP055761733, DOI: 10.1097/ALN.0000000000000984
MORRONE ET AL.: "Opioids Resistance in Chronic Pain Management", CURR NEUROPHARMACOL, vol. 15, no. 3, 2017, pages 444 - 456
MUHURI ET AL.: "Associations of Nonmedical Pain Reliever Use and Initiation of Heroin Use in the United States", CBHSQ DATA REV., August 2013 (2013-08-01)
NEGUS ET AL.: "Abuse Potential of Biased Mu Opioid Receptor Agonists", TRENDS PHARMACOL SCI, vol. 39, no. 11, 2018, pages 916 - 919, XP085508813, DOI: 10.1016/j.tips.2018.08.007
NEWMAN ET AL.: "N-(4-(4-(2,3-dichloro- or 2-methoxyphenyl)piperazin-l-yl)butyl)heterobiarylcarboxamides with functionalized linking chains as high affinity and enantioselective D receptor antagonists", J MED CHEM, vol. 52, no. 8, 2009, pages 2559 - 70, XP055117679, DOI: 10.1021/jm900095y
PHILIP S: "Portoghese Medicinal Chemistry Lectureship: Designing Bivalent or Bitopic Molecules for G-Protein Coupled Receptors. The Whole Is Greater Than the Sum of Its Parts", J MED CHEM, vol. 63, no. 5, 2020, pages 1779 - 1797
REGNIER G L ET AL: "Trophenylpropylpiperazine derivatives as new potent analgesic substances", JOURNAL OF MEDICINAL CHEMISTRY, AMERICAN CHEMICAL SOCIETY, US, vol. 3, no. 15, 1 January 1972 (1972-01-01), pages 295 - 301, XP002076588, ISSN: 0022-2623, DOI: 10.1021/JM00273A600 *
REUVENI HADAS ET AL: "Toward a PKB inhibitor: Modification of a selective PKA inhibitor by rational design", BIOCHEMISTRY,, vol. 41, no. 32, 13 August 2002 (2002-08-13), pages 10304 - 10314, XP002267237, ISSN: 0006-2960, DOI: 10.1021/BI0202530 *
ROSENBLUM ET AL.: "Opioids and the treatment of chronic pain: controversies, current status, and future directions", EXP CLIN PSYCHOPHARMACOL, vol. 16, no. 5, 2008, pages 405 - 16
SCHMID ET AL.: "Bias Factor and Therapeutic Window Correlate to Predict Safer Opioid Analgesics", CELL, vol. 171, no. 5, 2017, pages 1165 - 1175
SERRA-VINARDELL JENNY ET AL: "-xylitols (DIXs) by Click Chemistry", CHEMMEDCHEM COMMUNICATIONS, 1 January 2014 (2014-01-01), DE, pages n/a - n/a, XP055934075, ISSN: 1860-7179, DOI: 10.1002/cmdc.201402023 *
SILVA ET AL.: "The Escalation of the Opioid Epidemic Due to COVID-19 and Resulting Lessons About Treatment Alternatives", THE AMERICAN JOURNAL OF MANAGED CARE, vol. 26, no. 7, 2020
SOUNIER ET AL.: "Propagation of conformational changes during mu-opioid receptor activation", NATURE, vol. 524, no. 7565, 2015, pages 375 - 8, XP037205419, DOI: 10.1038/nature14680
THUY NGUYEN ET AL: "Discovery of Novel Proline-Based Neuropeptide FF Receptor Antagonists", ACS CHEMICAL NEUROSCIENCE, vol. 8, no. 10, 9 August 2017 (2017-08-09), US, pages 2290 - 2308, XP055533934, ISSN: 1948-7193, DOI: 10.1021/acschemneuro.7b00219 *
VERMA ET AL.: "The E2.65A mutation disrupts dynamic binding poses of SB269652 at the dopamine D and D receptors", PLOS COMPUT BIOL, vol. 14, no. 1, 2018, pages el005948
VOWLES ET AL.: "Rates of opioid misuse, abuse, and addiction in chronic pain: a systematic review and data synthesis", PAIN, vol. 156, no. 4, 2015, pages 569 - 76
WAGER ET AL.: "Central Nervous System Multiparameter Optimization Desirability: Application in Drug Discovery", ACS CHEM NEUROSCI, vol. 7, no. 6, 2016, pages 767 - 75
WAGER ET AL.: "Moving beyond rules: the development of a central nervous system multiparameter optimization (CNS MPO) approach to enable alignment of druglike properties", ACS CHEM NEUROSCI, vol. 1, no. 6, 2010, pages 435 - 49
WAGER T. T. ET AL.: "Moving beyond rules: the development of a central nervous system multiparameter optimization (CNS MPO) approach to enable alignment of druglike properties", ACS CHEM. NEUROSCI., vol. 1, no. 6, 2010, pages 435 - 449
YOU: "Dopamine D3R antagonist VK4-116 attenuates oxycodone self-administration and reinstatement without compromising its antinociceptive effects", NEUROPSYCHOPHARMACOLOGY, vol. 44, no. 8, 2019, pages 1415 - 1424, XP036803797, DOI: 10.1038/s41386-018-0284-5

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