Novel methods for preparing imaging compounds

Abstract

The present invention relates to novel methods for preparing compounds of formula I. Diagnostic compositions and their use in the selective detection of disorders and abnormalities associated with tau aggregates, such as Alzheimer's disease (AD) and other tauopathies, for example, by using positron emission tomography (PET) imaging, are also disclosed.

Description

[Technical field]

[0001] The present invention relates to novel methods for preparing compounds of formula I that can be used for the selective detection of disorders and abnormalities associated with tau aggregates, such as Alzheimer's disease (AD) and other tauopathies, for example using positron emission tomography (PET) imaging. Diagnostic compositions comprising the obtained compounds, as well as their use in diagnosis and imaging, are also the subject of this application. [Background technology]

[0002] Alzheimer's disease is a neurological disorder believed to be primarily caused by amyloid plaques, which are extracellular accumulations of abnormal deposits of amyloid-beta (Aβ) aggregates in the brain or eye. Another major neuropathological hallmark in AD is intracellular neurofibrillary tangles (NFTs) caused by aggregation of hyperphosphorylated tau (tubulin-associated unit) protein, phosphorylated tau or pathological tau and its conformers. This pathology of AD is shared with many neurodegenerative tauopathies, especially certain types of frontotemporal dementia (FTD). In AD brains, tau pathology (tauopathy) develops later than amyloid pathology, but the causative role of Aβ protein in AD, which constitutes the backbone of the so-called amyloid cascade hypothesis (Hardy et al., Science 1992, 256, 184-185, and more recently Musiek et al., Nature Neurosciences 2015, 18(6), 800-806, "Three dimensions of the amyloid hypothesis: time, space and 'wingmen'"), remains a subject of debate.

[0003] Currently, the only way to definitively diagnose AD is to identify plaques and tangles in brain tissue by histological analysis of biopsy or autopsy material after the death of an individual. In addition to AD, tau plays an important role in other (non-AD) neurodegenerative diseases. Such non-AD tauopathies include, for example, supranuclear palsy (PSP), Pick's disease (PiD), and corticobasal degeneration (CBD).

[0004] Compounds of general formula A have been proposed as being useful for the selective detection of disorders and abnormalities associated with tau aggregates, such as Alzheimer's disease (AD) and other tauopathies, and certain methods for preparing said compounds have been described in the prior art.

[0005] [ka]

[0006] In the method disclosed by Gobbi et al. in WO2015 / 052105, 18 The precursor having a nitro group instead of F was treated in a microwave oven with [ 18 After the synthesis steps, the compound of formula A is, among others, 1) HPLC using a mobile phase of methanol and triethylamine; and 2) Reconstitution using a solid phase extraction cartridge to capture the compound of formula A and subsequent elution from the cartridge with ethanol diluted in saline (0.9% NaCl in water). The product was purified by a two-step procedure including:

[0007] This method afforded the compound of formula A in 26.1% yield.

[0008] Gobbi et al. further describe two methods in J. Med. Chem. 2017, vol. 60, pp. 7350-7370: a) Microwave method: 18[F]fluoride was captured on a cation exchange cartridge and activity was eluted with a Kryptofix® / potassium carbonate mixture. After addition of acetonitrile, the mixture was dried at elevated temperature. The dried [ 18 The vial containing the [F] fluoride mixture was transferred to a microwave apparatus and 0.5 mg of the precursor molecule (unprotected nitro derivative) in 400 μL DMSO was added. The vial was irradiated by microwave at 50 W for 240 s. The resulting solution was diluted and purified by preparative HPLC (C-18 column, acetonitrile / trimethylamine buffer, pH 7.2). The product peak was collected, diluted with water and passed through a C-18 Sep-Pak Plus cartridge. The cartridge was washed with water and 18 The F-labeled product was eluted with ethanol and diluted with saline solution. b) Heating method: 18 [F] fluoride was captured on a cation exchange cartridge and activity was eluted with a Kryptofix® / potassium carbonate mixture. After addition of acetonitrile, the mixture was dried at high temperature. 0.5 mg of the precursor molecule (unprotected nitro derivative) in 400 μL DMSO was added and the solution was heated at 160° C. for 10 min. The resulting solution was diluted and purified by preparative HPLC (C-18 column, acetonitrile / trimethylamine buffer, pH 7.2). The product peak was collected, diluted with water and passed through a C-18 Sep-Pak Plus cartridge. The cartridge was washed with water and 18 The F-labeled product was eluted with ethanol and diluted with saline solution.

[0009] Thus, the process for the preparation of the compound of formula A in the aforementioned prior art has two purification / reconstitution steps, which is only partially automated in the case of the microwave process as shown in FIG.

[0010] The nitro precursor (and major by-product) of the methods described in the prior art has poor solubility in ethanol, acetonitrile and acetonitrile / aqueous buffer mixtures used for purification (preparative HPLC), especially when aqueous buffer mixtures with neutral pH are used. Only 0.5-0.7 mg of precursor was used in the prior art examples.

[0011] It is an object of the present invention to provide an improved process for preparing compounds of formula I (as outlined in Figure 2) which is more cost and time efficient than prior art processes. In addition, the yield of the process should also be improved. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] WO2015 / 052105 [Non-patent literature]

[0013] [Non-Patent Document 1] Hardy et al., Science 1992, 256, 184-185 [Non-Patent Document 2] Musiek et al., Nature Neurosciences 2015, 18(6), pp. 800-806, "Three dimensions of the amyloid hypothesis: time, space and 'wingmen'" [Non-Patent Document 3] Gobbi et al., J. Med. Chem. 2017, Vol. 60, pp. 7350-7370 [Non-Patent Document 4] Greene and Wuts, Protecting groups in Organic Synthesis, 3rd ed., pp. 494-653 [Non-Patent Document 5] Synthesis (1982), pp. 85-125, Table 2, Carey [Non-Patent Document 6] Sundberg, Organic Synthesis, (1995), pp. 279 - 281, Table 5.8 [Non - Patent Document 7] Netscher, Recent Res. Dev. Org. Chem., 2003, 7, pp. 71 - 83 [Non - Patent Document 8] Coenen, Fluorine - 18 Labeling Methods: Features and Possibilities of Basic Reactions, (2006) [Non - Patent Document 9] Schubiger P.A., Friebe M., Lehmann L. (eds.), PET - Chemistry - The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp. 15 - 50 [Non - Patent Document 10] A. Andreadis et al., Biochemistry 31, (1992) pp. 10626 - 10633 [Non - Patent Document 11] M. Tolnay et al., IUBMB Life, 55(6): pp. 299 - 305, 2003 [Non - Patent Document 12] Remington's Pharmaceutical Sciences, 18th Edition, Mack Publishing Company, Easton, PA, 1990, p. 1445 [Non - Patent Document 13] P. J. Kocienski, Protecting Groups, 3rd Edition, 2003 [Non - Patent Document 14] Remington's Pharmaceutical Sciences, 15th Edition, Mack Publishing Co., New Jersey(1975) [Brief Explanation of the Drawings]

[0014] [Figure 1]FIG. 1 is a schematic overview of the selected prior art method by Gobbi et al. [Diagram 2] FIG. 1 is a schematic overview of the method of the present invention. [Diagram 3] This is the configuration of the GE Tracerlab FX synthesizer. [Figure 4] This is the configuration of the IBA Synthera synthesizer. Summary of the Invention [Means for solving the problem]

[0015] The present invention relates to the following items: 1. Compound of Formula I

[0016] [ka]

[0017] A method for preparing A) A compound of formula II

[0018] [ka]

[0019] wherein X is H or PG; LG is a leaving group, PG is an amine protecting group. of 18 reacting with a F fluorinating agent; and B) optionally, when X is PG, cleaving the protecting group PG; and C) subjecting the resulting compound of formula I to high performance liquid chromatography (HPLC) using a mobile phase containing ethanol and water. A method comprising: 2. The process according to item 1, wherein X is PG, step B is absent and the protecting group PG is cleaved in step A. 3. The process according to item 1, wherein X is PG and the protecting group PG is cleaved in step B. 4. The method according to any one of items 1 to 3, wherein the ratio of ethanol to water in the mobile phase is from about 5 / 95 v / v to about 80 / 20 v / v. 5. The method according to any of items 1 to 4, wherein the pH of the mobile phase is from about 0 to about 8, preferably from about 1 to about 3, more preferably from about 2 to about 3.0, and even more preferably from about 2.2 to about 2.8. 6. The method according to any of items 1 to 5, wherein the mobile phase further comprises a buffer preferably selected from alkali metal dihydrogen phosphates, dialkali metal hydrogen phosphates, trialkali metal phosphates, alkali metal acetates, alkaline earth metal acetates, alkaline earth metal formates, mono / di / trialkali metal citrates. 7. The method according to any one of items 1 to 6, wherein the high performance liquid chromatography (HPLC) is carried out under a pressure of about 50 to about 400 bar, preferably about 50 to about 250 bar. 8. The process according to any one of items 1 to 7, wherein step A, optional step B and step C are an automated process carried out on an automated synthesizer. 9. The method according to any one of items 1 to 8, wherein a fraction containing the compound of formula I is obtained by high performance liquid chromatography (HPLC), and this fraction is subjected to step D) sterile filtration. 10. The method according to any one of items 1 to 9, which does not comprise a solid phase extraction of a compound of formula I after step C, preferably does not comprise a solid phase extraction of a compound of formula I before or after step C. 11. The process according to any one of items 1 to 10, wherein the compound of formula I is not subjected to chromatography after the high performance liquid chromatography (HPLC) of step C, preferably the compound of formula I is not subjected to chromatography other than the high performance liquid chromatography (HPLC) of step C. 12. Compounds of formula I obtainable by the process according to any one of items 1 to 12.

[0020] [ka]

[0021] and optionally a diagnostically acceptable carrier, diluent, adjuvant or excipient. 13. The composition according to item 12 for use in diagnosis. 14. The composition according to item 12 for use in imaging tau aggregates, in particular for use in imaging tau aggregates by positron emission tomography. 15. The disorder is Alzheimer's disease (AD), familial AD, Creutzfeldt-Jakob disease, pugilistically impaired encephalopathy, Down's syndrome, Gerstmann-Sträussler-Scheinker disease, inclusion body myositis, prion protein cerebral amyloid angiopathy, traumatic brain injury (TBI), amyotrophic lateral sclerosis, Guam parkinsonism dementia complex, non-Guamese motor neuron disease with neurofibrillary tangles, argyrophilic granule disease, corticobasal degeneration (CBD), lithiasis, cerebrovascular disease, cerebrovascular accident ... Diffuse neurofibrillary tangles with calcification, frontotemporal dementia with parkinsonism linked to chromosome 17, Hallervorden-Spatz disease, multiple system atrophy, Niemann-Pick disease type C, pallidopontinigral degeneration, Pick's disease (PiD), progressive subcortical gliosis, progressive supranuclear palsy (PSP), subacute sclerosing panencephalitis, tangle-only dementia, postencephalitic parkinsonism, myotonic dystrophy, tau panencephalitis, astrocyte-associated AD , certain prion diseases (GSS with tau), mutations in LRRK2, chronic traumatic encephalitis, familial British dementia, familial Danish dementia, frontotemporal lobar degeneration, Guadeloupe parkinsonism, neurodegeneration with cerebral iron accumulation, SLC9A6-associated mental retardation, white matter tauopathy with microspheroidal glial inclusions, traumatic stress syndrome, epilepsy, Lewy body dementia (LBD), hereditary cerebral hemorrhage with amyloidosis (Dutch type), mild 15. The composition for use according to item 13 or 14, selected from cognitive impairment (MCI), multiple sclerosis, Parkinson's disease, atypical parkinsonism, HIV-associated dementia, adult-onset diabetes mellitus, senile cardiac amyloidosis, endocrine tumors, glaucoma, ocular amyloidosis, primary retinal degeneration, macular degeneration (such as age-related macular degeneration (AMD)), optic nerve drusen, optic neuropathy, optic neuritis and lattice dystrophy; preferably, Alzheimer's disease. 16. The composition for use according to item 13 or 14, wherein the disorder is selected from Huntington's disease, ischemic stroke, psychosis in AD. 17. A composition for use according to any one of items 13 to 16, which is administered by injection. 18. The composition as defined in item 12 for use in the diagnosis of a disorder associated with tau aggregates or for use in the diagnosis of a tauopathy, in particular when the diagnosis is performed by positron emission tomography. 19. The composition for use according to item 18, wherein the tauopathy is a 3R tauopathy. 20. The composition for use according to item 18, wherein the tauopathy is a 4R tauopathy. 21. The disorder is Alzheimer's disease (AD), familial AD, Creutzfeldt-Jakob disease, pugilistically impaired syndrome, Down's syndrome, Gerstmann-Sträussler-Scheinker disease, inclusion body myositis, prion protein cerebral amyloid angiopathy, traumatic brain injury (TBI), amyotrophic lateral sclerosis, Guam parkinsonism dementia complex, non-Guam motor neuron disease with neurofibrillary tangles, argyrophilic granule disease, and corticobasal degeneration (CBD). , diffuse neurofibrillary tangles with calcifications, frontotemporal dementia with parkinsonism linked to chromosome 17, Hallervorden-Spatz disease, multiple system atrophy, Niemann-Pick disease type C, pallidopontinigral degeneration, Pick's disease (PiD), progressive subcortical gliosis, progressive supranuclear palsy (PSP), subacute sclerosing panencephalitis, tangle-only dementia, postencephalitic parkinsonism, myotonic dystrophy, tau panencephalitis, astrocyte-related AD with tau, certain prion diseases (GSS with tau), mutations in LRRK2, chronic traumatic encephalitis, familial British dementia, familial Danish dementia, frontotemporal lobar degeneration, Guadeloupe parkinsonism, neurodegeneration with cerebral iron accumulation, SLC9A6-associated mental retardation, white matter tauopathy with microspheroidal glial inclusions, traumatic stress syndrome, epilepsy, Lewy body dementia (LBD), hereditary cerebral hemorrhage with amyloidosis (Dutch type) ), mild cognitive impairment (MCI), multiple sclerosis, Parkinson's disease, atypical parkinsonism HIV-associated dementia, adult-onset diabetes mellitus, senile cardiac amyloidosis, endocrine tumors, glaucoma, ocular amyloidosis, primary retinal degeneration, macular degeneration (such as age-related macular degeneration (AMD)), optic nerve drusen, optic neuropathy, optic neuritis and lattice dystrophy; preferably, the composition for use according to item 18 is selected from Alzheimer's disease. 22. The composition for use according to item 18, wherein the disorder is selected from Huntington's disease, ischemic stroke and psychosis in AD. 23. The composition for use according to item 21, wherein the disorder is Alzheimer's disease (AD). 24. The composition for use according to item 21, wherein the disorder is Parkinson's disease or atypical parkinsonism. 25. The composition for use according to item 21, wherein the disorder is progressive supranuclear palsy (PSP). 26. The composition for use according to item 21, wherein the disorder is Pick's disease (PiD). 27. The composition for use according to any one of items 18 to 26, wherein tau aggregates are imaged in the brain or in the eye. 28. A method for imaging tau aggregates, in particular a method for imaging tau aggregates by positron emission tomography, wherein an effective amount of a composition as defined in item 12 is administered to a patient. 29. A method for diagnosing a disorder associated with tau aggregates or a tauopathy, wherein an effective amount of a composition as defined in item 12 is administered to a patient, in particular wherein the diagnosis is performed by positron emission tomography. 30. The method according to item 29, wherein the tauopathy is a 3R tauopathy. 31. The method according to item 29, wherein the tauopathy is a 4R tauopathy. 32. The disorder is Alzheimer's disease (AD), familial AD, Creutzfeldt-Jakob disease, pugilistically impaired encephalopathy, Down's syndrome, Gerstmann-Sträussler-Scheinker disease, inclusion body myositis, prion protein cerebral amyloid angiopathy, traumatic brain injury, amyotrophic lateral sclerosis, Guam parkinsonism dementia complex, non-Guamese motor neuron disease with neurofibrillary tangles, argyrophilic granule disease, corticobasal degeneration, calcification Diffuse neurofibrillary tangles associated with glaucoma, frontotemporal dementia with parkinsonism linked to chromosome 17, Hallervorden-Spatz disease, multiple system atrophy, Niemann-Pick disease type C, pallidopontinigral degeneration, Pick's disease, progressive subcortical gliosis, progressive supranuclear palsy (PSP), subacute sclerosing panencephalitis, tangle-only dementia, postencephalitic parkinsonism, myotonic dystrophy, tau panencephalitis, astrocyte-related AD, among others. Certain prion diseases (GSS with tau), mutations in LRRK2, chronic traumatic encephalitis, familial British dementia, familial Danish dementia, frontotemporal lobar degeneration, Guadeloupe parkinsonism, neurodegeneration with cerebral iron accumulation, SLC9A6-associated mental retardation, white matter tauopathy with microspheroidal glial inclusions, traumatic stress syndrome, epilepsy, Lewy body dementia (LBD), hereditary cerebral hemorrhage with amyloidosis (Dutch type), mild cognitive impairment (MCI), multiple sclerosis, Parkinson's disease, atypical parkinsonism, HIV-associated dementia, adult-onset diabetes mellitus, senile cardiac amyloidosis, endocrine tumors, glaucoma, ocular amyloidosis, primary retinal degeneration, macular degeneration (such as age-related macular degeneration (AMD)), optic nerve drusen, optic neuropathy, optic neuritis and lattice dystrophy; preferably, Alzheimer's disease. 33. The method according to item 29, wherein the disorder is selected from Huntington's disease, ischemic stroke and psychosis in AD. 34. The method according to item 32, wherein the disorder is Alzheimer's disease (AD). 35. The method according to item 32, wherein the disorder is Parkinson's disease or atypical parkinsonism. 36. A method according to item 32, wherein the disorder is progressive supranuclear palsy (PSP). 37. The method according to item 32, wherein the disorder is Pick's disease (PiD). 38. The method according to any one of items 28 to 37, wherein tau aggregates are imaged in the brain or in the eye. 39. Use of a composition as defined in item 12 for the manufacture of a diagnostic agent for imaging tau aggregates, in particular for imaging tau aggregates by positron emission tomography. 40. Use of a composition as defined in item 12 for the manufacture of a diagnostic agent for diagnosing a disorder associated with tau aggregates or for diagnosing a tauopathy, in particular wherein the diagnosis is carried out by positron emission tomography. 41. The use according to item 40, wherein the tauopathy is a 3R tauopathy. 42. The use according to item 40, wherein the tauopathy is a 4R tauopathy. 43. The disorder is Alzheimer's disease (AD), familial AD, Creutzfeldt-Jakob disease, pugilistically impaired encephalopathy, Down's syndrome, Gerstmann-Sträussler-Scheinker disease, inclusion body myositis, prion protein cerebral amyloid angiopathy, traumatic brain injury, amyotrophic lateral sclerosis, Guam parkinsonism dementia complex, non-Guamese motor neuron disease with neurofibrillary tangles, argyrophilic granule disease, corticobasal degeneration, calcification Diffuse neurofibrillary tangles associated with glaucoma, frontotemporal dementia with parkinsonism linked to chromosome 17, Hallervorden-Spatz disease, multiple system atrophy, Niemann-Pick disease type C, pallidopontinigral degeneration, Pick's disease, progressive subcortical gliosis, progressive supranuclear palsy (PSP), subacute sclerosing panencephalitis, tangle-only dementia, postencephalitic parkinsonism, myotonic dystrophy, tau panencephalitis, astrocyte-related AD, among others. Certain prion diseases (GSS with tau), mutations in LRRK2, chronic traumatic encephalitis, familial British dementia, familial Danish dementia, frontotemporal lobar degeneration, Guadeloupe parkinsonism, neurodegeneration with cerebral iron accumulation, SLC9A6-associated mental retardation, white matter tauopathy with microspheroidal glial inclusions, traumatic stress syndrome, epilepsy, Lewy body dementia (LBD), hereditary cerebral hemorrhage with amyloidosis (Dutch type), mild cognitive impairment (MCI), multiple sclerosis, Parkinson's disease, atypical parkinsonism, HIV-associated dementia, adult-onset diabetes mellitus, senile cardiac amyloidosis, endocrine tumors, glaucoma, ocular amyloidosis, primary retinal degeneration, macular degeneration (such as age-related macular degeneration (AMD)), optic nerve drusen, optic neuropathy, optic neuritis and lattice dystrophy; preferably, Alzheimer's disease. 44. The use according to item 40, wherein the disorder is selected from Huntington's disease, ischemic stroke and psychosis in AD. 45. The use according to item 43, wherein the disorder is Alzheimer's disease (AD). 46. ​​The use according to item 43, wherein the disorder is Parkinson's disease or atypical parkinsonism. 47. Use according to item 43, wherein the disorder is progressive supranuclear palsy (PSP). 48. Use according to item 43, wherein the disorder is Pick's disease (PiD). 49. The use according to any one of items 39 to 48, wherein tau aggregates are imaged in the brain or in the eye. 50. Use of the composition according to item 12 as an analytical reference. 51. Use of a composition according to item 12 as an in vitro screening tool. 52. A method for collecting data for the diagnosis of a disorder associated with tau aggregates in a sample or patient, comprising: (a) contacting a sample or a specific body part or body region suspected of containing tau aggregates with a composition as defined in item 12 containing a compound of formula I, (b) binding a compound of formula I to tau aggregates; (c) detecting the compound of formula I bound to tau aggregates; and (d) optionally correlating the presence or absence of a compound of formula I that binds to tau aggregates with the presence or absence of tau aggregates in the sample or in a particular body part or region. A method comprising: 53. A method for determining the amount of tau aggregates in a tissue and / or body fluid, comprising: (a) providing a sample representative of the tissue and / or body fluid to be tested; (b) testing the sample for the presence of tau aggregates using a composition as defined in item 12 containing a compound of formula I; (c) determining the amount of the compound of formula I bound to the tau aggregates; and (d) calculating the amount of tau aggregates in the tissue and / or body fluid A method comprising: 54. A method for collecting data for determining a propensity for a disorder associated with tau aggregates in a patient, comprising detecting specific binding of a composition as defined in item 12 containing a compound of formula I in a sample or in situ to tau aggregates, wherein the detecting step comprises: (a) contacting a sample or a specific body part or region suspected of containing tau aggregates with a composition as defined in item 12, comprising a compound of formula I that specifically binds to tau aggregates; (b) binding a compound of formula I to tau aggregates to form a compound / tau aggregate complex; (c) detecting the formation of a compound / tau aggregate complex; (d) optionally correlating the presence or absence of the compound / tau aggregate complex with the presence or absence of tau aggregates in the sample or in a particular body part or region; and (e) Optionally, comparing the amount of compound / tau aggregates to a normal control value. A method comprising: 55. A method for collecting data to monitor residual disability in a patient suffering from a disorder associated with tau aggregates who has been treated with a pharmaceutical agent, comprising: (a) contacting a sample or a specific body part or region suspected of containing tau aggregates with a composition as defined in item 12, comprising a compound of formula I that specifically binds to tau aggregates; (b) binding a compound of formula I to tau aggregates to form a compound / tau aggregate complex; (c) detecting the formation of a compound / tau aggregate complex; (d) optionally correlating the presence or absence of the compound / tau aggregate complex with the presence or absence of tau aggregates in the sample or in a particular body part or region; and (e) Optionally, comparing the amount of compound / tau aggregates to a normal control value. A method comprising: 56. A method for collecting data to predict the response of a patient suffering from a disorder associated with tau aggregates to a pharmaceutical treatment, comprising: (a) contacting a sample or a specific body part or region suspected of containing tau aggregates with a composition as defined in item 12, comprising a compound of formula I that specifically binds to tau aggregates; (b) binding a compound of formula I to tau aggregates to form a compound / tau aggregate complex; (c) detecting the formation of a compound / tau aggregate complex; (d) optionally correlating the presence or absence of the compound / tau aggregate complex with the presence or absence of tau aggregates in the sample or in a particular body part or region; and (e) Optionally, comparing the amount of compound / tau aggregates to a normal control value. A method comprising:

[0022] definition The term "alkyl," unless otherwise defined, refers to a saturated straight or branched carbon chain containing from 1 to 6 carbon atoms.

[0023] "Halo" or "halogen" refers to F, Cl, Br, and I. Preferably, "halogen" is independently at each occurrence selected from F, Cl, and Br, more preferably from F and Cl, and even more preferably from F.

[0024] The term "amine protecting group" (PG) as used herein is any protecting group suitable for protecting an amine group during the anticipated chemical reaction. Examples of suitable protecting groups are well known to those skilled in the art. Suitable protecting groups are discussed, for example, in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, 3rd Edition, pp. 494-653, which is incorporated herein by reference. Protecting groups can be selected from carbamates, amides, imides, N-alkylamines, N-arylamines, imines, enamines, boranes, NP protecting groups, N-sulfenyl, N-sulfonyl and N-silyl. Particular preferred examples of the protecting group (PG) are carbobenzyloxy (Cbz), (p-methoxybenzyl)oxycarbonyl (Moz or MeOZ), tert-butyloxycarbonyl (BOC), 9-fluorenylmethyloxycarbonyl (FMOC), benzyl (Bn), p-methoxybenzyl (PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenylmethyl (trityl), methoxyphenyldiphenylmethyl (MMT) or dimethoxytrityl (DMT). More preferred examples of the protecting group PG include tert-butyloxycarbonyl (BOC), dimethoxytrityl (DMT) and triphenylmethyl (trityl). A more preferred example of the protecting group PG is tert-butyloxycarbonyl (BOC).

[0025] The term "carbamate amine protecting group" refers to an amine protecting group containing a *-CO-O group, where the asterisk indicates the bond to the amine. Examples are carbobenzyloxy (Cbz), (p-methoxybenzyl)oxycarbonyl (Moz or MeOZ), tert-butyloxycarbonyl (BOC), and 9-fluorenylmethyloxycarbonyl (FMOC).

[0026] The term "leaving group" (LG) as used herein means any leaving group, an atom or group of atoms that can be replaced by another atom or group of atoms. Examples are given, for example, in Synthesis (1982), pp. 85-125, Table 2; Carey and Sundberg, Organische Synthese, (1995), pp. 279-281, Table 5.8; or Netscher, Recent Res. Dev. Org. Chem., 2003, pp. 7, 71-83, Schemes 1, 2, 10 and 15, etc.). (Coenen, Fluorine-18 Labeling Methods: Features and Possibilities of Basic Reactions, (2006), Schubiger PA, Friebe M., Lehmann L. (eds.), PET-Chemistry - The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pages 15-50, in particular: page 25 scheme 4, page 28 scheme 5, page 30 table 4, page 33 figure 7). Preferably, the "Leaving Group" (LG) is selected from the group consisting of nitro, bromo, iodo, chloro, trialkylammonium, hydroxyl, boronic acid, iodonium, sulfonic acid ester. More preferably, the "Leaving Group" (LG) is nitro or trimethylammonium. It is understood that the compound containing trialkylammonium or iodonium may further comprise an anion. Even more preferably, the "Leaving Group" (LG) is nitro. Another more preferred "Leaving Group" (LG) is trimethylammonium.

[0027] The term "crown ether" as used herein means a compound composed of a ring containing several ether groups. More specifically, the term "crown ether" preferably refers to a monocyclic organic group, which may be substituted and contains 8-16 carbon atoms and 4-8 heteroatoms selected from N, O and S in the ring. Each of the one or more optional substituents may be independently selected from any organic group containing 1-15 carbon atoms and optionally 1-6 heteroatoms selected from N, O and S. Preferred examples of "crown ethers" are optionally substituted monocyclic rings containing 10-14 carbon atoms and 5-7 heteroatoms selected from N, O and S in the ring. Examples of "crown ethers" are optionally substituted monocyclic rings containing 12 carbon atoms and 6 heteroatoms selected from N and O in the ring. Specific examples include 18-crown-6, dibenzo-18-crown-6 and diaza-18-crown-6.

[0028] The term "cryptand" as used herein refers to a class of polycyclic compounds related to crown ethers, which have three chains attached to two nitrogen atoms. A well-known "cryptand" is 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (Kryptofix®).

[0029] Tau as used herein refers to a highly soluble microtubule-associated protein that is often found in neurons, including the six major isoforms, truncated or deleted forms, and other modified forms resulting from, for example, phosphorylation, glycosylation, glycation, prolyl isomerase, nitration, acetylation, polyamination, ubiquitination, sumoylation, and oxidation.Pathological tau or tau aggregates (neurofibrillary tangles, NFTs) as used herein refer to insoluble aggregates of hyperphosphorylated tau protein that contain paired helical fibrils and straight fibrils.Its presence is a hallmark of AD and other diseases known as tauopathies.

[0030] The tau gene contains 16 exons, and the major tau protein isoforms are encoded by 11 of these. Alternative splicing of exon 10 produces tau isoforms with either three (exon 10 deleted) or four (exon 10 present) repeat domains, known as 3R and 4R tau, respectively (A. Andreadis et al., Biochemistry 31, (1992) pp. 10626-10633; M. Tolnay et al., IUBMB Life, 55(6): pp. 299-305, 2003). In Alzheimer's disease, the ratio of 3R and 4R isoforms is similar. In contrast, in some tauopathies, one of the two isoforms predominates. As used herein, the term "3R tauopathy" refers to tauopathies in which the 3R isoform predominates, such as Pick's disease (PiD). As used herein, the term "4R tauopathy" refers to tauopathies in which the 4R isoform predominates, such as progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD).

[0031] As used hereinafter in the present description and claims, the term "pharmaceutically acceptable salts" refers to non-toxic derivatives of the compounds of the present disclosure, where the parent compound is modified by making salts of inorganic and organic acids. Inorganic acids include, but are not limited to, acids such as hydrochloric acid, nitric acid, or sulfuric acid. Organic acids include, but are not limited to, carboxylic acids such as fatty acids, alicyclic acids, aromatic acids, aromatic fatty acids, and heterocyclic acids, and sulfonic acids. The pharmaceutically acceptable salts of the present invention can be synthesized from parent compounds containing a basic or acidic moiety by conventional chemical methods. In general, such salts can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two. A list of suitable salts can be found in Remington's Pharmaceutical Sciences, 18th Edition, Mack Publishing Company, Easton, PA, 1990, page 1445, the disclosure of which is incorporated herein by reference.

[0032] "Pharmaceutically acceptable" or "acceptable for diagnostic use" is defined to refer to those compounds, materials, compositions and / or dosage forms that are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without undue toxicity, irritation, allergic response, or other problem or complication commensurate with a reasonable benefit / risk ratio.

[0033] The patient or subject in the present invention is typically an animal, particularly a mammal, more particularly a human.

[0034] "Chromatography" or "liquid chromatography" refers to a method for the separation of a mixture of compounds. The mixture is dissolved in a liquid and travels through a "stationary phase" via a "mobile phase". Separation is based on the interaction of the compounds in the mobile phase with the stationary phase. Such different interactions result in differential retention on the stationary phase, thus affecting the separation. Chromatography can be preparative or analytical. The purpose of preparative chromatography is to separate components of a mixture and is therefore a form of purification. Analytical chromatography is performed with small samples of material and is used to measure the proportions of compounds in a mixture.

[0035] "High performance liquid chromatography (HPLC)" is a form of liquid chromatography that uses very small particles (10 μm or less) of stationary phase and separates compounds by applying sufficiently high pressure. HPLC systems typically consist of a reservoir of mobile phase, a pump, a pump, a separation column (containing the stationary phase), and a detector. For the separation of radioactive compounds, a suitable HPLC system is equipped with a radioactivity detector. Optionally, the HPLC system has additional detectors, such as UV, photodiode array, refractive index, conductivity, fluorescence, mass analyzer.

[0036] "Solid-phase extraction (SPE)" is a sample preparation and / or purification process that includes two or more separate steps. First, compounds are dissolved or suspended in a liquid mixture of solvents and the liquid sample is passed through a stationary (solid) phase. Some compounds are retained in the stationary phase while others pass through. In a second step, the retained compounds are eluted with a suitable solvent. Optionally, the stationary phase is washed with another solution before the elution step. In contrast to HPLC techniques, the particle sizes used are much larger (e.g., 25 μm or more compared to HPLC with typical particle sizes of 10 μm or less) and therefore the pressures applied are much smaller (for HPLC, pressures are typically greater than 50 bar).

[0037] A "solid phase extraction cartridge (SPE cartridge)" is a syringe or container (eg, Sep Pak®) pre-filled with a stationary phase for SPE.

[0038] "Sterile filtration" is a method for sterilizing a solution by filtration through a microfilter. A microfilter is, for example, a filter having a pore size of about 0.25 μm or less, preferably about 20 nm to about 0.22 μm, which is typically used to remove microorganisms. Membrane filters used for microfiltration in manufacturing processes are generally made from materials such as mixed cellulose esters, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or polyethersulfone (PES).

[0039] As used herein, "automation" refers to the performance of synthesis and / or purification steps by suitable equipment (synthesizer).

[0040] The term "radioscavenger" refers to a compound that reduces the rate of radiolytic decomposition. Preferred radioscavenger include ascorbic acid and its salts, and gentisic acid and its salts. More preferred radioscavenger are ascorbic acid, sodium ascorbate, and mixtures thereof.

[0041] Including but not limited to IBA Synthera, GE Fastlab, GE Tracerlab MX, GE Tracerlab FX, GE Tracerlab FX, Trasis AllinOne, ORA Neptis Perform, ORA Neptis Mosaic, ORA Neptis Plug, Scintomics GPR, Synthera, Comecer Taddeo, Raytest Synchrom, Sofie Elixys, Eckert&Ziegler Modular Lab, Sumitomo Heavy Industries F100 F200 F300, Siemens Explora 18Suitable "synthesizers" for F-radiolabelling are well known to those skilled in the art.

[0042] "Radiochemical purity" means the percentage of total activity of a radionuclide present in its stated chemical form. Typically, radiochemical purity is determined by thin layer chromatography or HPLC.

[0043] The preferred definitions provided in the "Definitions" section apply to all of the embodiments described herein unless otherwise stated.

[0044] Methods of the Invention In a first aspect, the present invention is directed to a method for preparing a compound of formula I.

[0045] [ka]

[0046] The method comprises: A) A compound of formula II

[0047] [ka]

[0048] wherein X is H or PG; LG is a leaving group, PG is an amine protecting group. of 18 reacting with a F fluorinating agent; and B) optionally, when X is PG, cleaving the protecting group PG; and C) subjecting the obtained compound of formula I to high performance liquid chromatography (HPLC) using a mobile phase comprising a mixture of ethanol and water. Includes.

[0049] Preferred compounds of formula I are

[0050] [ka]

[0051] is selected from the group consisting of:

[0052] More preferred compounds of formula I are

[0053] [ka]

[0054] It is.

[0055] Preferred compounds of formula II are

[0056] [ka]

[0057] is selected from the group consisting of:

[0058] More preferred compounds of formula II are

[0059] [ka]

[0060] is selected from the group consisting of:

[0061] In these compounds, PG and LG are as defined in the "Definitions" section.

[0062] Even more preferred compounds of formula II are

[0063] [ka]

[0064] is selected from the group consisting of X - is a counter ion, e.g., halogen, CF3 SO 3 - and CF 3 CO 2 - is a counter ion selected from the group consisting of:

[0065] Process A Step A) comprises reacting a compound of formula II

[0066] [ka]

[0067] (In the formula, X is H or PG; LG is a leaving group, PG is an amine protecting group. of 18 F involves reacting with a fluorinating agent.

[0068] When X is H, a compound having formula I is obtained. When X is PG, a compound having formula III is obtained.

[0069] [ka]

[0070] An intermediate compound having the formula:

[0071] 18 F fluorinating agents are well known to those skilled in the art. 18 F-fluorinated drugs can be used. Typical examples include H 18 F, Alkaline or alkaline earth 18 F fluorides (e.g., K 18 F, Rb 18 F, Cs 18 F and Na 18 F). Optionally, 18F-fluorinated drugs can be used in combination with chelating agents such as cryptands (e.g.: 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]-hexacosane-Kryptofix®) or crown ethers (e.g.: 18-crown-6). Alternatively, 18 F-fluorinated drugs are 18 A tetraalkylammonium salt of F or 18 Tetraalkylphosphonium salts of F, such as 18 F Tetra (C 1 ~ 6 (alkyl) ammonium salt or 18 F Tetra (C 1 ~ 6 Examples of these include tetrabutylammonium [alkyl]phosphonium salts. 18 F]fluoride and tetrabutylphosphonium[ 18 [F] fluoride. Preferably, 18 F-fluorinated drugs are 18 F, H 18 F, Cs 18 F, Na 18 F or tetrabutylammonium [ 18 In an even more preferred embodiment, 18 F-fluorinated drugs are 18 In another preferred embodiment, 18 F-fluorinated drugs are tetrabutylammonium [ 18 F] fluoride.

[0072] 18 F-fluorination is typically carried out in a solvent, preferably selected from acetonitrile, dimethylsulfoxide, dimethylformamide, dimethylacetamide, amyl alcohol, tert-butyl alcohol or mixtures thereof, preferably the solvent contains or is acetonitrile or DMSO. Other solvents can also be used and are well known to those skilled in the art. The solvent can be water and / or other alcohols, e.g. C 1~10It may further comprise a linear, branched or cyclic alkanol as a co-solvent. In one preferred embodiment, 18 The solvent for carrying out F radiolabeling contains dimethylsulfoxide. In another preferred embodiment, 18 The solvent for carrying out F radiolabeling contains acetonitrile. In a preferred embodiment, 18 The solvent for carrying out F radiolabeling is dimethylsulfoxide. In another preferred embodiment, 18 The solvent for carrying out F radiolabeling is acetonitrile.

[0073] 18 F-fluorination is typically carried out for up to about 60 minutes. A preferred reaction time is up to about 30 minutes. More preferred reaction times are up to about 15 minutes. Typical reaction times are about 1-15 minutes, preferably 5-15 minutes, more preferably 10-15 minutes.

[0074] 18 F-fluorination is typically carried out under conventional or microwave-assisted heating at temperatures between about 60 and about 200° C. In a preferred embodiment, 18 The F-fluorination is carried out at about 100 to about 180° C. In a more preferred embodiment, 18 The F-fluorination is carried out at about 100 to about 160° C. Preferably, 18 The F-fluorination is carried out under conventional heating. Conventional heating is understood to be any heating that does not use microwaves.

[0075] The amount of starting material is not particularly limited. For example, about 0.5 to about 50 μmol of the compound of formula II can be used for the production of one batch of the compound of formula I. In a preferred embodiment, about 2 to about 25 μmol of the compound of formula II is used. In a more preferred embodiment, about 2.5 to about 15 μmol of the compound of formula II is used. In one embodiment, at least about 2 μmol of the compound of formula II is used. In a preferred embodiment, at least about 2.5 μmol of the compound of formula II is used. In a more preferred embodiment, at least about 3 μmol of the compound of formula II is used.

[0076] Typically, about 0.5 to about 10 mg of a compound of formula II can be used to prepare one batch of a compound of formula I. In a preferred embodiment, about 0.5 to about 5 mg of a compound of formula II is used. In a more preferred embodiment, about 1 to about 3 mg of a compound of formula II is used.

[0077] When X is PG, an intermediate compound having formula III is obtained: The protecting group PG can be cleaved either during step A or the optional subsequent step B.

[0078] Preferred compounds of formula III are

[0079] [ka]

[0080] is selected from the group consisting of:

[0081] In these compounds, PG is as defined in the "Definitions" section.

[0082] Process B Step B is an optional step which involves cleaving the protecting group PG from a compound of formula III to obtain a compound of formula I. As will be apparent to one skilled in the art, this step is not applicable if step A is carried out with a compound of formula II where X is hydrogen or if the protecting group PG has already been cleaved in step A.

[0083] Reaction conditions for cleavage of various protecting groups are well known to those skilled in the art and may be selected from, but are not limited to, those described in the textbook Protecting groups in Organic Synthesis, 3rd Edition, pages 494-653 by Greene and Wuts, and the textbook Protecting Groups, 3rd Edition, 2003 by P.J. Kocienski, all of which are incorporated herein by reference.

[0084] The conditions used in step B depend on the protecting group to be cleaved and are therefore not particularly limited.

[0085] Possible reaction conditions include i) heating at about 60 to about 160°C; ii) adding an acid and heating at about 0 to about 160°C; or iii) adding a base and heating at about 0 to about 160°C.

[0086] Preferred acids are hydrochloric acid, sulfuric acid and phosphoric acid. One preferred acid is sulfuric acid. Another preferred acid is phosphoric acid. Another preferred acid is hydrochloric acid. Preferred bases are sodium hydroxide and potassium hydroxide.

[0087] Preferred reaction conditions include the addition of an acid and heating at about 25° C. to 160° C., preferably 25° C. to 120° C., more preferably 90 to 120° C. Preferably, the reaction mixture is heated for about 1 to about 20 minutes, more preferably about 5 to about 15 minutes.

[0088] If desired, steps A and B can be carried out in the same or different reaction vessels. Preferably, steps A and B are carried out in the same reaction vessel.

[0089] If desired, the solution obtained after step B can be used as is in step C. Alternatively, the composition of the solution can be adapted so that it is more suitable for performing HPLC. For example, a buffer or diluent can be added before step C.

[0090] The preferred diluent is ethanol, water or a combination thereof.

[0091] In addition, the pH of the solution can be adapted. In a preferred embodiment, the pH is adjusted to about 6 or less, more preferably about 4 or less, or even more preferably about 3 or less, before step C. In a preferred embodiment, the pH is adjusted to about 0 to about 6, more preferably about 0 to about 4, and even more preferably about 1 to 3, before step C.

[0092] Process C Step C is a step in which the compound of formula I obtained in step A or, if used, step B, is subjected to HPLC using a mobile phase containing ethanol and water.

[0093] In the prior art, it was assumed that it was necessary to use two chromatographic steps to arrive at an injectable tracer, namely, first purification by HPLC of the compound of formula I and then reconstitution by SPE. The inventors have surprisingly found that when a mixture of ethanol and water is used as the mobile phase, the subsequent capture of the compound via solid phase extraction can be omitted. It is therefore possible to use a single chromatographic step for purification and preparation. This is 18 This is particularly important in the present case of radiofluorination since F has a half-life of only about 110 minutes, so the speed of the process to arrive at an injectable formulation of Compound I is of utmost importance.

[0094] Because the claimed methods are faster and less complicated than conventional methods, compounds of formula I can be obtained in higher decay-corrected yields.

[0095] The selection of a mixture of ethanol and water as the mobile phase has the added advantage that these two components are acceptable for diagnostic purposes and therefore may be retained in the composition administered to the patient (unlike methanol, acetonitrile, triethylamine and trimethylamine used in the prior art). Thus, the selection of ethanol and water as the mobile phase significantly reduces the time and cost required for the preparation of the compound of formula I and / or results in higher yields and higher radiochemical purity than prior art methods.

[0096] The method of the invention preferably does not comprise a solid phase extraction of a compound of formula I after step C, more preferably the method of the invention does not comprise a solid phase extraction of a compound of formula I before or after step C.

[0097] The compound of formula I is preferably not subjected to chromatography after the high performance liquid chromatography (HPLC) of step C, and more preferably the compound of formula I is not subjected to chromatography other than the high performance liquid chromatography (HPLC) of step C.

[0098] The mobile phase used in the HPLC method comprises ethanol and water, which may further contain acids, bases, buffers, salts and / or radioscavenger, and optionally mixtures thereof.

[0099] The ratio of ethanol to water is not particularly limited, but is preferably about 5 / 95 v / v to about 80 / 20 v / v, more preferably about 5 / 95 v / v to about 50 / 50 v / v, and even more preferably about 5 / 95 v / v to about 20 / 80 v / v.

[0100] The pH of the mobile phase is not limited, but it is preferably about 0 to about 8, preferably about 0 to about 6, more preferably about 1 to about 5, even more preferably about 1 to about 3, and even more preferably about 2.2 to about 2.8.

[0101] Possible buffer solutions may include salts which may be selected from alkali metal dihydrogen phosphates, dialkali metal hydrogen phosphates, trialkali metal phosphates, alkali metal acetates, alkaline earth metal acetates, alkaline earth metal formates, mono / di / trialkali metal citrates, the preferred alkali and alkaline earth metals being sodium and potassium.

[0102] Possible bases can be sodium hydroxide and / or potassium hydroxide.

[0103] If desired, the pH of the mobile phase can be adjusted using inorganic or organic acids. Examples of inorganic acids include ascorbic acid, citric acid, and acetic acid. Examples of organic acids include hydrochloric acid, sulfuric acid, and phosphoric acid, preferably phosphoric acid.

[0104] A radioscavenger is a compound that reduces the decomposition of the compound of formula I by radiolysis. Examples include ascorbic acid and ascorbate salts, gentisic acid and gentisate salts. Further examples include citric acid and citrate salts. More preferred radioscavenger is ascorbic acid, sodium ascorbate and mixtures thereof.

[0105] Preferably, the mobile phase comprises about 50 to about 500 mM buffer solution (e.g., alkaline dihydrogen phosphate) having a pH of about 1 to about 3, more preferably about 50 to about 250 mM buffer solution (e.g., alkaline dihydrogen phosphate) having a pH of about 1 to about 3, and even more preferably about 50 to about 150 mM buffer solution (e.g., alkaline dihydrogen phosphate) having a pH of about 1 to about 3.

[0106] A preferred mobile phase comprises about 5 to about 20% v / v ethanol, about 95 to about 80% v / v water, about 50 to about 150 mM buffer (e.g., alkaline dihydrogen phosphate) having a pH of about 1 to about 3, and optionally a radioscavenger. A more preferred mobile phase comprises about 5 to about 20% v / v ethanol, about 95 to about 80% v / v water, about 50 to about 150 mM buffer (e.g., alkaline dihydrogen phosphate) having a pH of about 2.2 to about 2.8, and optionally a radioscavenger.

[0107] Stationary phases for use in HPLC methods are well known and can be appropriately selected by one of skill in the art. In a preferred embodiment, the stationary phase is a "reversed phase" (RP) stationary phase.

[0108] Examples of RP-HPLC stationary phases include C18, C8, phenyl, cyano (e.g., cyanopropyl), pentafluorophenyl, amino (e.g., aminopropyl), amide (e.g., C 10~24 -alkane-aminopropyl), phenylhexyl functionalized resins or mixed phase resins.

[0109] In one embodiment, the particle size of the HPLC stationary phase is about 1.6 to about 15 μm. In a preferred embodiment, the particle size of the HPLC stationary phase is about 5 to about 10 μm. In another embodiment, the particle size of the HPLC stationary phase is about 10 μm.

[0110] Typically, the HPLC column has a diameter of about 2.0 to about 50 mm and a length of about 50 to about 300 mm. In a preferred embodiment, the HPLC column has a diameter of about 4.6 to about 20 mm and a length of about 150 to about 250 mm. In a more preferred embodiment, the HPLC column has dimensions of 10 x 250 mm.

[0111] The flow rate used in high performance liquid chromatography is not limited, and can be about 1 to about 20 mL / min, more typically about 2 to about 15 mL / min, and even more typically about 2 to about 7 mL / min.

[0112] The pressure used in high performance liquid chromatography is not particularly limited, and can be in the range of about 50 to about 400 bar, typically about 50 to about 250 bar, and more typically about 50 to 200 bar.

[0113] In one embodiment, about 1 to about 500 GBq 18 F] fluoride is used for the preparation of the compound of formula I. In a preferred embodiment, about 50 to about 500 GBq [ 18 In a more preferred embodiment, about 100 to about 500 GBq[F] fluoride is used for the preparation of the compound of formula I. 18 In an even more preferred embodiment, about 200 to about 500 GBq[F] fluoride is used for the preparation of the compound of formula I. 18 F] fluoride is used for the preparation of the compound of formula I.

[0114] In one embodiment, about 10 GBq or more of [ 18 [F] fluoride is used for the preparation of the compound of formula I. In a preferred embodiment, about 50 GBq or more of [ 18 In a more preferred embodiment, about 100 GBq or more of [F] fluoride is used for the preparation of the compound of formula I. 18 In an even more preferred embodiment, about 200 GBq or more of [F] fluoride is used for the preparation of the compound of formula I. 18 F] fluoride is used for the preparation of the compound of formula I.

[0115] In one embodiment, about 10 GBp or more of a radiolabeled compound of formula I is obtained. In a preferred embodiment, about 20 GBp or more of a radiolabeled compound of formula I is obtained. In a more preferred embodiment, about 50 GBp or more of a radiolabeled compound of formula I is obtained. In an even more preferred embodiment, about 100 GBp or more of a radiolabeled compound of formula I is obtained.

[0116] In one embodiment, the compound of formula I is obtained with a radiochemical purity of at least about 90%. In a preferred embodiment, the compound of formula I is obtained with a radiochemical purity of at least about 93%. In a preferred embodiment, the compound of formula I is obtained with a radiochemical purity of at least about 95%. In a more preferred embodiment, the compound of formula I is obtained with a radiochemical purity of at least about 98%.

[0117] Optional steps Since ethanol and water are included in the mobile phase, the HPLC fractions containing the compound of formula I can be used directly as an injectable formulation if desired, or the HPLC fractions containing the compound of formula I can be mixed with additional diagnostically acceptable components, such as diagnostically acceptable carriers, diluents, adjuvants, or excipients, to prepare an injectable formulation of the compound of formula I.

[0118] In a preferred step D, sterile filtration can be carried out after step C. If further components are added, sterile filtration can be carried out before or after their addition.

[0119] In one embodiment, step A, optional step B, and step C are performed using an automated synthesis device. Examples of such automated synthesis devices include, but are not limited to, IBA Synthera, GE Fastlab, GE Tracerlab MX, GE Tracerlab FX, GE Tracerlab FX, Trasis AllinOne, ORA Neptis Perform, ORA Neptis Mosaic, ORA Neptis Plug, Scintomics GPR, Synthera, Comecer Taddeo, Raytest Synchrom, Sofie Elixys, Eckert&Ziegler Modular Lab, Sumitomo Heavy Industries F100 F200 F300, and Siemens Explora.

[0120] A preferred method is to A) Compound of formula II, where LG=nitro and PG=Boc, is dissolved in DMSO, preferably with K 18 F and tetrabutylammonium [ 18 F] fluoride 18 F]-fluorinating agent at about 100 to about 180° C., preferably about 120 to about 180° C., more preferably about 140 to about 160° C., whereby the Boc protecting group is cleaved under radiolabeling conditions; C) HPLC purification of the compound of formula I using an ethanol / sodium dihydrogen phosphate buffer mixture (about 5 to about 20% EtOH), the buffer having a pH of about 1 to about 3, preferably about 2.2 to about 2.8; and D) If desired, combining the HPLC fractions containing the compound of formula I with components acceptable for further diagnostic use in a formulation intended for administration to a patient. If desired, the HPLC fraction is passed through a sterile filter before or after mixing with further diagnostically acceptable components of the formulation.

[0121] Another preferred method comprises the steps of: A) Compound of formula II, where LG=trimethylammonium and PG=trityl, is dissolved in DMSO, preferably with K 18 F and tetrabutylammonium [ 18 F] fluoride 18 F]-fluorinating agent or acetonitrile at about 80 to about 180° C., preferably about 100 to about 180° C.; B) adding phosphoric acid and heating at about 90 to about 120° C. for about 1 to about 15 minutes; C) HPLC purification of the compound of formula I using an ethanol / sodium dihydrogen phosphate buffer mixture (about 5 to about 20% EtOH), the buffer having a pH of about 1 to about 3, preferably about 2.2 to about 2.8; and D) If desired, combining the HPLC fractions containing the compound of formula I with components acceptable for further diagnostic use in a formulation intended for administration to a patient. If desired, the HPLC fraction is passed through a sterile filter before or after mixing with further diagnostically acceptable components of the formulation.

[0122] Unless otherwise specified, all hydrogens in compounds of formula I, II or III are 1 Even if H or 2 It may be H (deuterium).

[0123] The method of the present invention may provide a diagnostic composition comprising a compound of formula I. Due to the speed and low complexity of the method, 18 The amount of F-labeled compound I can be higher than in conventional methods. This method also provides compounds of formula I with high radiochemical purity (e.g., at least about 90%, preferably at least about 93%, more preferably at least about 95%, and even more preferably at least about 98%) at high radioactivity levels (e.g., at least about 20 GBq of the compound of formula I, preferably at least about 50 GBq of the compound of formula I, more preferably at least about 100 GBq of the compound of formula I).

[0124] The diagnostic compositions are suitable for use in diagnosis. They are particularly suitable for the diagnosis of disorders associated with tau aggregates or for imaging tau aggregates, in particular for imaging tau aggregates using positron emission tomography (PET).

[0125] Diagnostic Compositions A "diagnostic composition" is defined in the present invention as a composition comprising a compound of formula I. For in vivo applications, the diagnostic composition should be in a form suitable for administration to a mammal, such as a human. Preferably, the diagnostic composition further comprises a physiologically acceptable carrier, diluent, adjuvant or excipient. Administration to a patient is preferably performed by injection of the composition as a solution. Such compositions may optionally contain further ingredients such as solvents, buffers, diagnostically acceptable solubilizers and diagnostically acceptable stabilizers or antioxidants.

[0126] Acceptable excipients for diagnostic use are well known in the pharmaceutical art and are described, for example, in Remington's Pharmaceutical Sciences, 15th Edition, Mack Publishing Co., New Jersey (1975). Diagnostic excipients can be selected with reference to standard pharmaceutical practice. The excipient must be acceptable in the sense of not being deleterious to the recipient thereof.

[0127] Preferably, the diagnostic composition comprises about 1% v / v to about 20% v / v ethanol based on the total amount of ethanol and water. More preferably, the diagnostic composition comprises about 1% v / v to about 15% v / v ethanol based on the total amount of ethanol and water. Even more preferably, the diagnostic composition comprises about 5% v / v to about 10% v / v ethanol based on the total amount of ethanol and water. In addition to the above components, the diagnostic composition comprises water. The amount of water is selected so that the total amount of the composition is 100%.

[0128] The compounds of formula I are administered by injection. Examples of such administration include one or more of intravenous, intraarterial, intraperitoneal, intrathecal, intraventricular, intraurethral, ​​intrasternal, intracranial, intramuscular or subcutaneous administration of the compound and / or using infusion techniques. For parenteral administration, the compounds are best used in the form of a sterile solution which may contain other excipients. The solution should be suitably buffered (preferably to a pH of 3 to 9, more preferably to a pH of 4.0 to 8.5) if necessary. The preparation of suitable parenteral formulations under sterile conditions is readily accomplished by standard pharmaceutical techniques well known to those skilled in the art.

[0129] The diagnostic compositions of the invention can be formulated in a manner known per se to those skilled in the art, for example as described in Remington's Pharmaceutical Sciences, 15th Edition, Mack Publishing Co., New Jersey (1975).

[0130] The dose of the detectably labeled compound of formula I may vary depending on the exact compound to be administered, the patient's weight, the size and type of the sample, and other variables, as will be apparent to a practitioner of skill in the art. In general, the mass may preferably range from about 0.001 μg to about 100 μg per patient dose, preferably from about 0.01 μg to about 50 μg per patient dose. The radioactive dose may be, for example, from about 100 to about 600 MBq, more preferably from about 150 to about 450 MBq per injection, and even more preferably from about 150 to about 200 MBq.

[0131] In particular, in one embodiment, a disease or disorder that can be detected and monitored with a detectably labeled compound of Formula I is a disease or condition associated with tau protein aggregates, e.g., a 3R or 4R tauopathy.

[0132] Diseases or conditions that can be detected and monitored with the detectably labeled compounds obtained by the methods of the present invention include neurodegenerative disorders such as tauopathies. Examples of diseases and conditions that can be detected and monitored are caused by or associated with the formation of neurofibrillary lesions. This is the main brain pathology in tauopathies. Diseases and conditions include a heterogeneous group of neurodegenerative diseases or conditions, including diseases or conditions that show the coexistence of tau and amyloid pathology. Examples of diseases involving tau aggregates are generally listed as tauopathies, and these include Alzheimer's disease (AD), Creutzfeldt-Jakob disease, Punch-Drunkenness, Down's syndrome, Gerstmann-Sträussler-Scheinker disease, inclusion body myositis, prion protein cerebral amyloid angiopathy, traumatic brain injury, amyotrophic lateral sclerosis, Parkinsonism-Dementia Complex of Guam, Non-Guam Motor Neuron Disease with Neurofibrillary Tangles, Argyrophilic granule disease, corticobasal degeneration, diffuse neurofibrillary tangles with calcifications, frontotemporal dementia with parkinsonism linked to chromosome 17, Hallervorden-Spatz disease, multiple system atrophy, Niemann-Pick disease type C, pallidopontinigral degeneration, Pick's disease, progressive subcortical gliosis, progressive supranuclear palsy (PSP), subacute sclerosing panencephalitis, tangle-only dementia, postencephalitic parkinsonism, myotonic dystrophy, tachycardial infarction, and glaucoma. Panencephalitis, astrocyte-related AD, certain prion diseases (GSS with tau), mutations in LRRK2, chronic traumatic encephalitis, familial British dementia, familial Danish dementia, frontotemporal lobar degeneration, Guadeloupe parkinsonism, neurodegeneration with cerebral iron accumulation, SLC9A6-associated mental retardation, white matter tauopathy with microspheroidal glial inclusions, traumatic stress syndrome, epilepsy, Lewy body dementia (LBD), amyloidosis The diseases and conditions that can be detected and monitored include, but are not limited to, hereditary cerebral hemorrhage with retinal edema (Dutch type), mild cognitive impairment (MCI), multiple sclerosis, Parkinson's disease, atypical parkinsonism, HIV-associated dementia, adult-onset diabetes mellitus, senile cardiac amyloidosis, endocrine tumors, glaucoma, ocular amyloidosis, primary retinal degeneration, macular degeneration (such as age-related macular degeneration (AMD)), optic nerve drusen, optic neuropathy, optic neuritis, and lattice dystrophies. , Alzheimer's disease (AD), familial AD, Creutzfeldt-Jakob disease, punch-drunk syndrome, Down's syndrome, Gerstmann-Sträussler-Scheinker disease, inclusion body myositis, prion protein cerebral amyloid angiopathy, traumatic brain injury (TBI), amyotrophic lateral sclerosis, Guam parkinsonism dementia complex, non-Guam motor neuron disease with neurofibrillary tangles, argyrophilic granule disease, corticobasal degeneration (CBD), diffuse neurofibrillary tangles with calcifications, frontotemporal dementia with parkinsonism linked to chromosome 17, Hallervorden-Spatz disease, multiple system atrophy, Niemann-Pick disease type C, pallidopontinigral degeneration, Pick's disease (PiD), progressive subcortical gliosis, progressive supranuclear palsy (PSP), subacute sclerosing panencephalitis, tangle-only dementia, postencephalitic parkinsonism, Myotonic dystrophy, tau panencephalitis, astrocyte-associated AD, certain prion diseases (GSS with tau), mutations in LRRK2, chronic traumatic encephalitis, familial British dementia, familial Danish dementia, frontotemporal lobar degeneration, Guadeloupe parkinsonism, neurodegeneration with cerebral iron accumulation, SLC9A6-associated mental retardation and white matter tauopathy with microspheroidal glial inclusions, more preferably Alzheimer's disease (AD), Creutzfeldt-Jakob disease, punch-drunk syndrome, amyotrophic lateral sclerosis, argyrophilic granule disease, corticobasal degeneration, frontotemporal dementia with parkinsonism linked to chromosome 17, Pick's disease, progressive supranuclear palsy (PSP), tangle-only dementia, parkinsonism dementia complex of Guam, Hallervorden-Spatz disease and frontotemporal lobar degeneration. Preferably, the disease or condition is Alzheimer's disease, Parkinson's disease or atypical parkinsonism, progressive supranuclear palsy (PSP), or Pick's disease (PiD), more preferably Alzheimer's disease.

[0133] Further examples of diseases or conditions that can be detected and monitored with detectably labeled compounds obtained by the methods of the present invention include psychosis in Huntington's disease, ischemic stroke and AD.

[0134] The method of the present invention has several important advantages over the prior art methods: After the compound of formula I is prepared, only a single chromatographic step is required, without subsequent reconstitution via SPE, so the setup is much simpler than the prior art setup, in which two different chromatographic steps are performed.

[0135] The method has proven to be very robust: due to the choice of ethanol and water as the mobile phase with adjusted pH, larger amounts of precursor (e.g., more than 1 mg) can be used without precipitation being caused.

[0136] 18 The F-labelled compound of formula I can be easily separated from the precursor of the compound of formula II and possible by-products.

[0137] Moreover, high yields and purities can be achieved. For example, it is possible to obtain decay-uncorrected yields of at least about 35%. Product activities can be at least about 20 GBq, preferably at least about 50 GBq, and more preferably at least about 100 GBq. Radiochemical purity can be at least about 95%, preferably at least about 98%, at low and high radioactivity levels (e.g., at least about 100 GBq).

[0138] This invention is illustrated by the following examples which should not be construed as limiting. EXAMPLES

[0139] Abbreviation

[0140] [Table 1A]

[0141] [Table 1B]

[0142] Experimental Data All reagents and solvents were obtained from commercial suppliers and used without further purification. 1 H) spectra were recorded on a Bruker DRX-400 MHz NMR spectrometer or a Bruker AV-400 MHz NMR spectrometer in deuterated solvents. Mass spectra (MS) were recorded on an Advion CMS mass spectrometer. Chromatography was performed using silica gel (Fluka: Silica gel 60, 0.063-0.2 mm) and suitable solvents as indicated in the specific examples. Flash purification was performed using a Biotage Isolera One flash purification system using HP-Sil (Biotage) or puriFlash-columns (Interchim) and solvent gradients as indicated in the specific examples. Thin layer chromatography (TLC) was performed on silica gel plates with UV detection.

[0143] Synthesis of test compounds Preparation Example A

[0144] [ka]

[0145] Process A Commercially available 2,6-dibromopyridine (4.12 g, 16.6 mmol) was suspended in ethanol (40 mL) and hydrazine hydrate (10 mL, 97.6 mmol) in water (ca. 50-60%) was added. The mixture was heated in a sand bath at ca. 115° C. for 18 h. The solvent was removed and the residue was purified by chromatography on silica using ethyl acetate / n-heptane (60 / 40) to give the title compound as an off-white solid (3.05 g, 93%). 1 H-NMR (400 MHz, CDCl 3 ): δ = 7.33 (t, 1H), 6.83 (d, 1H), 6.67 (d, 1H), 6.00 (br-s, 1H), 3.33-3.00 (br-s, 2H)

[0146] Process B The title compound from step A above (10 g, 53.2 mmol) and commercially available 1-Boc-4-piperidone (10.6 g, 53.2 mmol) were added to a 500 mL flask and mixed until a homogenous blend was obtained. Polyphosphoric acid (80 g, 115% H 3 PO 4 Baseline) was added and the mixture was heated in a sand bath at about 160°C. At about 120°C, the Boc-protecting group was cleaved and the reaction mixture foamed. After completion of the Boc-cleavage, the foam collapsed and the dark reaction mixture was stirred at about 160°C for 20 hours. The reaction mixture was allowed to cool to room temperature and water (400 mL) was added. The reaction mixture was stirred / sonicated until the gummy material was dissolved. The reaction mixture was then placed in an ice bath and the pH of the solution was adjusted to pH 12 by adding solid pellets of sodium hydroxide (exothermic). The precipitate was filtered off and washed with water (400 mL) to remove salts. The precipitate was dissolved in dichloromethane / methanol (9 / 1; 1500 mL) by sonication and washed with water (2 x 400 mL) to remove residual salts and insoluble material. The organic phase was diluted with Na 2 SO 4 The mixture was dried at 40° C., filtered and the solvent removed under reduced pressure. The dark residue was treated with dichloromethane (100 mL), sonicated for 5 min and the precipitate was collected by filtration. The precipitate was washed with dichloromethane (40 mL) and air-dried to give the title compound as a beige solid (3.5 g, 26%). 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 11.5 (br-s, 1H), 7.72 (d, 1H), 7.15 (d, 1H), 3.86-3.82 (m, 2H), 3.06-3.00 (m, 2H), 2.71-2.65 (m, 2H)

[0147] Process C The title compound from step B above (1.75 g, 6.94 mmol) was suspended in xylene (380 mL) and manganese(IV) oxide (6.62 g, 76.9 mmol) was added. The reaction mixture was then heated in a sand bath at about 160° C. for 36 h. The cooled reaction mixture was evaporated under reduced pressure and the residue was suspended in dichloromethane / methanol (1 / 1; 400 mL) and stirred at room temperature for 30 min. The reaction mixture was then filtered through a filter paper to remove manganese(IV) oxide, which was washed with methanol (50 mL). The combined filtrates were evaporated under reduced pressure and the dark residue was purified by chromatography on silica (50 g HP-SIL-cartridge) using a Biotage Isolera system with an ethyl acetate / heptane gradient (5 / 95 to 100 / 0) to remove non-polar impurities, followed by dichloromethane / methanol (9 / 1→4 / 1) to give the title compound as a dark yellow solid. The combined yield from the two runs was 1.77 g (51%). 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 12.52 (br-s, 1H), 9.42 (s, 1H), 8.61 (d, 1H), 8.53 (d, 1H), 7.56-7.52 (m, 2H)

[0148] Preparation Example B

[0149] [ka]

[0150] Process A To a suspension of the title compound from Preparation Example A (0.776 g, 0.72 mmol) in dichloromethane (65 mL) was added triethylamine (1.86 mL, 13 mmol) and trityl-chloride (2.63 g, 9.39 mmol). After addition of 4-(dimethylamino)-pyridine (0.074 g, 0.608 mmol), the reaction mixture was stirred at room temperature for 16 hours. The reaction mixture was diluted with dichloromethane (150 mL) and water (50 mL). The organic phase was separated and washed with Na 2 SO4 The mixture was dried at 40° C., filtered and the solvent removed in vacuo. The residue was purified on a HP-Sil SNAP cartridge (50 g) using a Biotage Isolera One purification system with an ethyl acetate / n-heptane gradient (5 / 95→100 / 0→100 / 0) to give the title compound B as a pale yellow solid (0.831 g, 54%). Unreacted starting material was recovered by flushing the cartridge with ethyl acetate / methanol (90 / 10) to give the starting material as an off-white solid (0.195 g, 25%). 1 H-NMR (400 MHz, CDCl 3 ) δ = 9.22 (s, 1H), 8.23 ​​(d, 1H), 8.13 (d, 1H), 7.48-7.42 (m, 7H), 7.33-7.22 (m, 12H), 6.41 (d, 1H) MS (ESI); m / z = 490.03 / 491.96 [M+H] +

[0151] Preparation Example C

[0152] [ka]

[0153] Process A To a suspension of the title compound from Preparation Example A (0.482 g, 1.94 mmol) in dichloromethane (40 mL) was added triethylamine (1.15 mL, 8 mmol) and 4,4'-(chloro(phenyl)methylene)bis(methoxybenzene) (DMTrt-Cl) (1.963 g, 5.8 mmol). After addition of 4-(dimethylamino)-pyridine (0.046 g, 0.377 mmol), the reaction mixture was stirred at room temperature for 3 days. The reaction mixture was diluted with dichloromethane (100 mL) and water (40 mL). The organic phase was separated and diluted with Na 2 SO 4The mixture was dried at 40° C., filtered and the solvent removed in vacuo. The residue was purified on a HP-Sil SNAP cartridge (50 g) using a Biotage Isolera One purification system with an ethyl acetate / n-heptane gradient (5 / 95→100 / 0→100 / 0) to give the title compound C as a pale yellow solid (0.825 g, 72%). Unreacted starting material was recovered by flushing the cartridge with ethyl acetate / methanol (90 / 10) to give the starting material as an off-white solid (0.042 g, 8.8%). 1 H-NMR (400 MHz, CDCl 3 ) δ = 9.23 (s, 1H), 8.23 ​​(d, 1H), 8.13 (d, 1H), 7.39-7.31 (m, 6H), 7.29-7.25 (4H), 6.80 (d, 4H), 6.41 (dd, 1H), 3.81 (s, 6H)

[0154] Example 1

[0155] [ka]

[0156] Process A To a mixture of degassed 1,4-dioxane (4.3 mL) and water (1 mL) in a microwave vial was added [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (0.0084 g, 0.01 mmol), followed by the title compound of Preparation Example A (0.05 g, 0.2 mmol), (2-fluoropyridin-4-yl)boronic acid (0.035 g, 0.245 mmol) and cesium carbonate (0.133 g, 0.41 mmol). The reaction mixture was then heated in a sand bath at about 115°C for 6 hours. The reaction mixture was diluted with ethyl acetate (60 mL) and water (20 mL) and the organic phase was separated and added Na 2 SO 4The mixture was dried at 40° C., filtered and the solvent was evaporated in vacuo. The dark residue was purified by chromatography on silica (25 g HP-SIL) using a Biotage Isolera system with a dichloromethane / methanol gradient (100 / 0→95 / 5→90 / 10→80 / 20) to give the title compound 1 as an off-white solid (0.033 g, 63%). 1 H-NMR (400 MHz, DMSO-d 6 ) δ = 12.50 (br-s, 1H), 9.45 (s, 1H), 8.83 (d, 1H), 8.56-8.52 (m, 1H), 8.43-8.39 (m, 1H), 8.19-8.14 (m, 2H), 7.92 (s, 1H), 7.54-7.50 (m, 1H) MS (ESI): m / z = 265.04 [M+H] +

[0157] Example 2

[0158] [ka]

[0159] Process A To a suspension of the title compound of Preparation Example A (0.430 g, 1.73 mmol) in dichloromethane (25 mL) was added triethylamine (1.93 mL, 13.89 mmol) and di-tert-butyl dicarbonate (2.27 g, 10.02 mmol). After addition of 4-(dimethylamino)-pyridine (0.042 g, 0.34 mmol), the reaction mixture was stirred at room temperature for 3 days. The solvent was removed under reduced pressure and the residue was purified using a Biotage Isolera One purification system on a HP-Sil SNAP cartridge (25 g) with an ethyl acetate / n-heptane gradient (5 / 95→100 / 0→100 / 0) to give the title compound as a white solid (0.558 g, 92%). 1 H-NMR (400 MHz, CDCl 3) δ = 9.28 (s, 1H), 8.73 (d, 1H), 8.22 (d, 2H), 7.59 8d, 1H), 1.80 (s, 9H)

[0160] Process B To a mixture of degassed 1,4-dioxane (3 mL) and water (0.7 mL) in a microwave vial was added [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloro-methane (0.0058 g, 0.007 mmol), followed by the title compound from step A above (0.05 g, 0.143 mmol), (6-fluoropyridin-3-yl)boronic acid (0.024 g, 0.17 mmol) and cesium carbonate (0.092 g, 0.286 mmol). The reaction mixture was then heated in a sand bath at about 100° C. for 4 hours. The reaction mixture was diluted with ethyl acetate (80 mL) and water (35 mL) and the organic phase was separated and added Na 2 SO 4 The mixture was dried at 40° C., filtered and the solvent was evaporated in vacuo. The dark residue was purified by chromatography on silica (12 g, puriFlash, Interchim) using a Biotage Isolera system with a dichloromethane / methanol gradient (100 / 0→98 / 2→95 / 5→90 / 10→80 / 20) to give the less polar Boc-protected compound (0.0255 g, 49%) and the more polar title compound 2 as an off-white solid (0.0116 g, 31%). Highly polar title compound 2: 1 H-NMR (400 MHz, DMSO-d 6 ) δ = 12.40 (br-s, 1H), 9.40 (s, 1H), 9.05 (s, 1H), 8.78-8.70 (m, 2H), 8.51 (d, 1H), 8.02 (d, 1H), 7.50 (d, 1H), 7.36 (dd, 1H) MS (ESI): m / z = 265.09 [M+H] + Less polar Boc-protected compounds: 1H-NMR (400 MHz, DMSO-d 6 ) δ = 9.48 (s, 1H), 9.13 (d, 1H), 8.84-8.78 (m, 2H), 8.68 (d, 1H), 8.23 ​​(d, 1H), 8.19 (d, 1H), 7.40 (dd, 1H), 1.75 8s, 9H)

[0161] The synthesis of title compound 2 was first described in WO2015 / 052105 (Example 1) by a different synthetic method.

[0162] Synthesis of radiolabeled precursors (Example 3-a)

[0163] [ka]

[0164] Process A To a mixture of degassed 1,4-dioxane (4.3 mL) and water (1 mL) in a microwave vial was added [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (0.0084 g, 0.01 mmol), the title compound of Preparation Example B (0.1 g, 0.2 mmol), 2-nitro-4-(4,4,5,5,-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (0.061 g, 0.245 mmol) and cesium carbonate (0.133 g, 0.41 mmol). The reaction mixture was then heated in a sand bath at about 115° C. for 6 hours. The reaction mixture was diluted with ethyl acetate (60 mL) and water (20 mL) and the organic phase was separated and added Na 2 SO 4 The mixture was dried at 40° C., filtered and the solvent was evaporated in vacuo. The dark residue was purified by chromatography on silica (25 g pufiFlash-column, Interchim) using a Biotage Isolera system with an ethyl acetate / n-heptane gradient (5 / 95→100 / 0→100 / 0) to give the title compound 3-a as a pale yellow solid (0.082 g, 75%). 1 H-NMR (400 MHz, CDCl 3 ) δ = 9.32 (s, 1H); 8.56 (d, 1H), 8.48 (d, 1H), 8.33 (s, 1H); 8.30 (d, 1H), 7.85 (d, 1H), 7.69 (d, 1H), 7.58-7.54 (m, 5H), 7.32-7.25 (m, 10H), 6.48 (d, 1H) MS (ESI): m / z = 534.28 [M+H] + .

[0165] (Example 3-b) Method a:

[0166] [ka]

[0167] Process A To a solution of 3-a (0.0396 g, 0.074 mmol) in dichloromethane (5 mL) was added trifluoroacetic acid (1.2 mL). The reaction mixture was stirred at room temperature for 6 h and methanol (2 mL) was added. The solvent was evaporated in vacuum and the residue was dissolved / suspended in methanol (5 mL). The solvent was evaporated in vacuum and the residue was dissolved / suspended again in methanol (5 mL). The solvent was evaporated in vacuum and the residue was suspended in dichloromethane (2 mL). After addition of triethylamine (1 mL, 7.2 mmol), di-tert-butyl dicarbonate (0.098 g, 0.43 mmol) and 4-(dimethylamino)-pyridine (0.0018 g, 0.014 mmol), the reaction mixture was stirred at room temperature for 18 h. The reaction mixture was diluted with ethyl acetate (50 mL) and water (20 mL). The organic phase was separated and Na 2 SO 4The mixture was dried at 40° C., filtered and the solvent removed in vacuo. The residue was purified using a Biotage Isolera One purification system on silica (25 g pufiFlash, Interchim) with an ethyl acetate / n-heptane gradient (5 / 95→100 / 0→100 / 0) to elute non-polar by-products, followed by ethyl acetate / methanol (95 / 5) to give the title compound 3-b as a pale yellow solid (0.0184 g, 63%). 1 H-NMR (400 MHz, CDCl 3 ) δ = 9.36 (s, 1H), 9.15 (s, 1H), 8.82-8.76 (m, 2H), 8.57 (d, 1H), 8.45 (d, 1H), 8.36 (d, 1H), 8.07 (d, 1H), 1.87 (s, 9H) MS (ESI); m / z = 391.82 [M+H] +

[0168] Method b:

[0169] [ka]

[0170] Process A To a mixture of degassed 1,4-dioxane (2.2 mL) and water (0.5 mL) in a microwave vial was added [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (0.0042 g, 0.005 mmol), followed by the title compound of Preparative Example C (0.055 g, 0.1 mmol), 2-nitro-4-(4,4,5,5,-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (0.0305 g, 0.12255 mmol) and cesium carbonate (0.067 g, 0.205 mmol). The reaction mixture was then heated in a sand bath at about 115° C. for 6 hours. The reaction mixture was diluted with ethyl acetate (20 mL) and the precipitate was collected by filtration, washed with water (10 mL) and methanol (5 mL), and air-dried to give 3-c (0.0277 g, 95%).

[0171] Process B To a suspension of the crude title compound from Step A above (0.0277 g, 0.095 mmol) in dichloromethane (4 mL) was added triethylamine (1 mL, 7.2 mmol), di-tert-butyl dicarbonate (0.2 g, 0.86 mmol) and 4-(dimethylamino)-pyridine (0.0036 g, 0.028 mmol). The reaction mixture was stirred at room temperature for 16 h and diluted with ethyl acetate (50 mL) and water (20 mL). The organic phase was separated and washed with Na 2 SO 4 The mixture was dried at 40° C., filtered and the solvent removed in vacuo. The residue was purified on a Biotage Isolera One purification system on silica (25 g pufiFlash, Interchim) with an ethyl acetate / n-heptane gradient (5 / 95→100 / 0→100 / 0) to elute non-polar by-products, followed by ethyl acetate / methanol (95 / 5) to give the title compound 3-b as a pale yellow solid (0.0261 g, 70%). 1 H-NMR (400 MHz, CDCl 3 ) δ = 9.38 (s, 1H), 9.16 (s, 1H), 8.83-8.78 (m, 2H), 8.58 (d, 1H), 8.46 (d, 1H), 8.38 (d, 1H), 8.09 (d, 1H), 1.88 (s, 9H) MS (ESI); m / z = 391.85 [M+H] + ; 291.74 [M+H-Boc] +

[0172] (Example 3-d)

[0173] [ka]

[0174] Process A To a mixture of degassed 1,4-dioxane (2.2 mL) and water (0.5 mL) in a microwave vial was added [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (0.0042 g, 0.005 mmol), followed by the title compound of Preparative Example C (0.055 g, 0.1 mmol), 2-nitro-4-(4,4,5,5,-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (0.0305 g, 0.12255 mmol) and cesium carbonate (0.067 g, 0.205 mmol). The reaction mixture was then heated in a sand bath at about 115° C. for 6 hours. The reaction mixture was diluted with ethyl acetate (20 mL) and the precipitate was collected by filtration, washed with water (10 mL) and methanol (5 mL), and air-dried to give 3-c as a grey solid (0.0277 g, 95%).

[0175] Process B To a suspension of the crude title compound from Step A above (0.0277 g, 0.095 mmol) in dichloromethane (4 mL) was added triethylamine (1 mL, 7.2 mmol), 4,4'-(chloro(phenyl)methylene)bis(methoxybenzene) (0.081 g, 0.29 mmol) and 4-(dimethylamino)-pyridine (0.0036 g, 0.028 mmol). The reaction mixture was stirred at room temperature for 18 hours and diluted with ethyl acetate (50 mL) and water (20 mL). The organic phase was separated and diluted with Na 2 SO 4 It was dried at 400 C, filtered and the solvent was removed in vacuo. The residue was purified using a Biotage Isolera One purification system on silica (25 g pufiFlash, Interchim) with an ethyl acetate / n-heptane gradient (5 / 95→100 / 0→100 / 0) to give the title compound 3-d as a pale yellow solid (0.0261 g, 44%). 1 H-NMR (400 MHz, CDCl 3) δ = 9.32 (s, 1H), 8.58 (d, 1H), 8.50 (d, 1h), 8.36 (s, 1H), 8.30 (d, 1H), 7.85 (d, 1H), 7.74 (d, 1H), 7.52-7.42 (m, 6H), 7.27-7.23 (m, 4H), 6.80 (d, 4H), 6.49 (d, 1H), 3.78 (s, 6H)

[0176] (Example 3-e)

[0177] [ka]

[0178] Process A Commercially available N,N-dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-amine (0.25 g, 1 mmol) was dissolved in dichloromethane (5 mL). To the resulting stirred solution was added methyl trifluoromethanesulfonate (0.124 mL, 1.1 mmol) dropwise at room temperature. The solution was stirred at room temperature for 4 hours. The reaction mixture was concentrated to remove dichloromethane and the residue was dried in vacuo to give a yellow glass / foam which was used directly in the next step.

[0179] Process B To a solution of degassed 1,4-dioxane (12 mL) and water (3 mL) in a microwave vial was added [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (0.034 g, 0.04 mmol), the title compound of Preparation Example B (0.4 g, 0.816 mmol), the crude title compound from Step A above (approximately 1 mmol), and cesium carbonate (0.544 g, 1.68 mmol). The reaction mixture was heated in a sand bath at approximately 120° C. for 6 hours. The reaction mixture was diluted with ethyl acetate (150 mL) and water (50 mL), the organic phase was separated, and sodium carbonate was added. 2 SO 4The mixture was dried at 40° C., filtered and the solvent was evaporated in vacuo. The dark residue was purified by chromatography on silica (25 g HP-Ultra) using a Biotage Isolera system with an ethyl acetate / n-heptane gradient (5 / 95→100 / 0→100 / 0) to elute unreacted starting material and non-polar by-products. The gradient was then changed to dichloromethane / methanol (100 / 0→95 / 5→90 / 10) to give the dimethylamine derivative as a pale yellow glass (0.127 g, 29%; MS (ESI): m / z = 532.27 [M+H]+) and the methylamine derivative as a grey solid (0.0547 g, 13%; MS (ESI): m / z = 519.18 [M+H]+). The gradient was changed again to dichloromethane / methanol (90 / 10→80 / 20) and maintained at (80 / 20) to afford the title compound 3-e as a brown solid (0.104 g, 18%). 1 H NMR (400 MHz, DMSO-d6) δ = 9.47 (s, 1H); 8.89 (d, 1H), 8.55 (d, 1H), 8-35-8.32 (m, 2H), 8.29 (d, 1H), 7.63-7.57 (m, 5H), 7.48 (d, 1H), 7.34-7.25 (m, 10H), 6.48 (d, 1H), 3.60 (s, 9H) MS (ESI): m / z = 546.26 [M+H] +

[0180] (Example 3-f) (Trimethylammonium / NH precursor) (ACI-3613)

[0181] [ka]

[0182] Process A 3-e (0.199 g, 0.364 mmol) was suspended in dichloromethane (10 mL). After the addition of trifluoroacetic acid (10 mL), the reaction mixture was stirred at room temperature for 18 h. The solvent was removed under reduced pressure, the residue was dissolved in methanol (10 mL), and the solvent was removed under reduced pressure. The methanol treatment of the residue was repeated two more times. The residue was then suspended in dichloromethane (20 mL) and sonicated for about 5 min. The precipitate was collected by filtration, washed with dichloromethane (10 mL), and air-dried to give the title compound 3-f as a grey solid (0.127 g, 83%). 1 H-NMR (400 MHz, DMSO-d 6 ) δ = 13.76 (br-s, 1H), 9.84 (s, 1H); 8.12 (d, 1H), 8.89 (d, 1H), 8.80 (d, 1H), 8.75 (s, 1H), 8.54-8.50 (m, 2H), 8.04 (d, 1H), 3.72 (s, 9H) MS (ESI): m / z = 303.91 [M+H] +

[0183] (Example 4-a)

[0184] [ka]

[0185] Process A To a mixture of degassed 1,4-dioxane (3 mL) and water (0.7 mL) in a microwave vial was added [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (0.0058 g, 0.007 mmol), followed by the title compound from Step A of Example 2 (0.05 g, 0.143 mmol), 2-nitro-5-(4,4,5,5,-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (0.0428 g, 0.17 mmol) and cesium carbonate (0.092 g, 0.286 mmol). The reaction mixture was then heated in a sand bath at about 100° C. for 4 hours. The reaction mixture was diluted with ethyl acetate (80 mL) and water (35 mL) and the organic phase was separated and added Na 2 SO 4 The mixture was dried at 40° C., filtered and the solvent was evaporated in vacuo. The dark residue was purified by chromatography on silica (12 g, puriFlash, Interchim) using a Biotage Isolera system with a dichloromethane / methanol gradient (100 / 0→98 / 2→95 / 5→90 / 10→80 / 20) to give the title compound 4-a as a pale yellow solid (0.0173 g, 31%). 1 H NMR (400 MHz, CDCl 3 / CD 3 OD) δ = 9.45 (d, 1H), 9.32 (s, 1H), 8.93 (dd, 1H), 8.68-8.64 (m, 2H), 8.46 (d, 1H), 8.35 (d, 1H), 8.14 (d, 1H), 1.82 (s, 9H) MS (ESI): m / z = 392.13 [M+H] +

[0186] The synthesis of the title compound 4-a was first described in WO2015 / 052105 (Example 3a) by a different synthetic method.

[0187] 18 Radiolabeling of precursors with F Examples of radiolabeled precursors

[0188] [ka]

[0189] General radiolabeling method A (radiolabeling, deprotection, HPLC and SPE) carried out on a tracerlab FX as shown in Figure 3 - Comparative Example [ 18 [F]fluoride was captured on a Sep-Pak Accell Plus QMA light cartridge (Waters) and 2 CO 3 / Kryptofix® 2.2.2 solution. Elution was performed at 95°C with He or N 2 The water was removed using a stream of water and coevaporated to dryness with MeCN (1 mL). The solution of the dissolved precursor was then dried and cooled to 100° C. 18 The reaction vial was sealed and heated at 150 °C for 15 min. Then, acid (HCl, H 2 SO 4 Or H 3 PO 4 ) was added and the mixture was heated at 150° C. for 10 min. The reaction mixture was diluted with 1 mL NaOH and 2.4 mL prep. The HPLC mobile phase and crude product were purified via semi-preparative HPLC (e.g., Phenomenex, Gemini C18, 5 μm, 250×10 mm) at 4 mL / min. The isolated tracer was diluted with water (20 mL+10 mg / mL sodium ascorbate), captured on a C-18 Plus cartridge (Waters), washed with water (10 mL+10 mg / mL sodium ascorbate), eluted with ethanol (1 mL), and mixed with water (14 mL+10 mg / mL sodium ascorbate).

[0190] General radiolabeling method B (radiolabeling, HPLC and SPE) carried out on a tracerlab FX as shown in FIG. 3 - Comparative Example [ 18 [F]fluoride was captured on a Sep-Pak Accell Plus QMA light cartridge (Waters) and2 CO 3 / Kryptofix® 2.2.2 solution. Elution was performed at 95°C with He or N 2 The water was removed using a stream of water and coevaporated to dryness with MeCN (1 mL). The solution of the dissolved precursor was then dried and cooled to 100° C. 18 [F]F-Kryptofix complex was added. The reaction vial was sealed and heated at 150 °C for 15 min. The reaction mixture was diluted with 0.5-1 mL of NaOH and 2.4 mL of prep. The HPLC mobile phase and crude product were purified via semi-preparative HPLC (e.g., Phenomenex, Gemini C18, 5 μm, 250 × 10 mm) at 4 mL / min. The isolated tracer was diluted with water (20 mL + 10 mg / mL sodium ascorbate), captured on a C-18 Plus cartridge (Waters), washed with water (10 mL + 10 mg / mL sodium ascorbate), eluted with ethanol (1 mL), and mixed with water (14 mL + 10 mg / mL sodium ascorbate).

[0191] General radiolabeling method C (radiolabeling, HPLC) performed on IBA Synthera + Synthera HPLC as shown in FIG. [ 18 [F]fluoride was captured on a Sep-Pak Accell Plus QMA light cartridge (Waters) and 2 CO 3 / Kryptofix® 2.2.2 solution. He or N 2 The water was removed using a stream of water and coevaporated to dryness. The solution of the dissolved precursor was then dried and cooled to 100°C. 18 The reaction vial was sealed and heated at 150 °C for 15 min. The reaction mixture was diluted with 1 M H 3 PO 4The aqueous components of the prep were diluted with 0.5-1 mL and 3-3.5 mL. The HPLC mobile phase and crude product were purified via semi-preparative HPLC (e.g., Waters XBridge Peptide BEH C18, 130 Å, 10 μm, 10 mm×250 mm) at 3-6 mL / min. Fractions containing the product (5-10 mL) were collected and diluted with diluent containing 0-2 mL EtOH, 10-20 mL water and 0-4 mL phosphate buffer concentrate (Braun, 3.05 g disodium monohydrogen phosphate dodecahydrate, 0.462 g sodium dihydrogen phosphate dihydrate in 20 mL water for injection) and / or sodium ascorbate (100-1000 mg) and / or sodium citrate (100-1000 mg) and / or gentisic acid (20-200 mg).

[0192] General radiolabeling method D (radiolabeling, HPLC) performed on a tracerlab FX as shown in FIG. 3 [ 18 [F]fluoride was captured on a Sep-Pak Accell Plus QMA light cartridge (Waters) and 2 CO 3 / Kryptofix® 2.2.2 solution. Elution was performed at 95°C with He or N 2 The water was removed using a stream of water and coevaporated to dryness with MeCN (1 mL). The solution of the dissolved precursor was then dried and cooled to 100° C. 18 The reaction vial was sealed and heated at 150 °C for 15 min. The reaction mixture was diluted with 1 M H 3 PO 4The aqueous components of the prep were diluted with 0.5-1 mL and 3-3.5 mL. The HPLC mobile phase and crude product were purified via semi-preparative HPLC (e.g., Waters XBridge Peptide BEH C18, 130 Å, 10 μm, 10 mm x 250 mm or Gemini 5 μm C18, 250 x 10 mm, Phenomenex: 00G-4435-N0) at 3-6 mL / min. The fractions containing the product (5-10 mL) were collected and diluted with diluent containing 0-2 mL EtOH, 10-20 mL water and 0-4 mL phosphate buffer concentrate (Braun) and / or sodium ascorbate (100-1000 mg) and / or sodium citrate (100-1000 mg) and / or gentisic acid (20-200 mg).

[0193] General radiolabeling method E (radiolabeling, deprotection, HPLC) performed on a tracerlab FX as shown in Figure 3. [ 18 [F]fluoride was captured on a Sep-Pak Accell Plus QMA light cartridge (Waters) and 2 CO 3 / Kryptofix® 2.2.2 solution. Elution was performed at 95°C with He or N 2 The water was removed using a stream of water and coevaporated to dryness with MeCN (1 mL). The solution of the dissolved precursor was then dried and cooled to 100° C. 18 The reaction vial was sealed and heated at 150 °C for 15 min. Then, 0.5 M H 2 SO 41 mL of 1M NaOH was added and the mixture was heated at 100 °C for 10 min. The reaction mixture was diluted with 0.5-1 mL of 1M NaOH and 2-3 mL of the aqueous component of the prep. The HPLC mobile phase and crude product were purified via semi-preparative HPLC (e.g., Waters XBridge Peptide BEH C18, 130 Å, 10 μm, 10 mm x 250 mm or Gemini 5 μm C18, 250 x 10 mm, Phenomenex: 00G-4435-N0) at 3-6 mL / min. Fractions containing the product (5-10 mL) were collected and diluted with diluent medium containing 0-2 mL of EtOH, 10-20 mL of water and 0-4 mL of phosphate buffer concentrate (Braun) and / or sodium ascorbate (100-1000 mg) and / or sodium citrate (100-1000 mg) and / or gentisic acid (20-200 mg).

[0194] General radiolabeling method F (radiolabeling, deprotection, HPLC) performed on IBA Synthera + Synthera HPLC as shown in Figure 4. [ 18 [F]fluoride was captured on a Sep-Pak Accell Plus QMA light cartridge (Waters) and 2 CO 3 / Kryptofix® 2.2.2 solution. He or N 2 The water was removed using a stream of water and coevaporated to dryness. The solution of the dissolved precursor was then dried and cooled to 100°C. 18 The reaction vial was sealed and heated at 110-120 °C for 5-10 min. After fluorination, 1 M H 3 PO 40.5-1 mL of hexanes was added and the reaction mixture was heated at 100-110 °C for 10-15 min. The mixture was diluted with 3-3.5 mL of the aqueous component of the prep. HPLC mobile phase and the crude product was purified via semi-preparative HPLC (e.g., Waters XBridge Peptide BEH C18, 130 Å, 10 μm, 10 mm × 250 mm) at 3-6 mL / min. Fractions containing the product (5-10 mL) were collected and diluted with 0-2 mL of EtOH, 10-20 mL of water and 0-4 mL of phosphate buffer concentrate (Braun, 3.05 g of disodium monohydrogen phosphate dodecahydrate, 0.462 g of sodium dihydrogen phosphate dihydrate in 20 mL of water for injection) and / or a diluent containing sodium ascorbate (100-1000 mg) and / or sodium citrate (100-1000 mg) and / or gentisic acid (20-200 mg).

[0195] Determination of radiochemical purity Radiochemical purity was determined by analytical HPLC, e.g., column: Atlantis T3, Waters, 100 x 4.6 mm, 3 μm, 100; mobile phase A: 40 mM sodium acetate, final pH 5.0 with glacial acetic acid; mobile phase B: 35% methanol in acetonitrile; flow rate: 1.8 mL / min; gradient: 0-5 min 15-32% B, 5-8 min 32-80% B, 8-12 min 80% B, 12-13 min 80-15% B, 13-16 min 15% B.

[0196] 18 Results for the synthesis of F-Ib:

[0197] [Table 2A]

[0198] [Table 2B]

Claims

1. Compounds of Formula I 【Chemistry 1】 A method for preparing A) A compound of formula II 【Chemistry 2】 wherein X is H or PG; LG is a leaving group, PG is an amine protecting group. of 18 reacting with a F fluorinating agent; and B) optionally, when X is PG, cleaving the protecting group PG; and C) subjecting the resulting compound of formula I to high performance liquid chromatography (HPLC) using a mobile phase containing ethanol and water. A method comprising:

2. 2. The method of claim 1, wherein X is PG, step B is absent and the protecting group PG is cleaved in step A, or wherein X is PG and the protecting group PG is cleaved in step B.

3. 3. The method according to claim 1 or 2, wherein the ratio of ethanol to water in the mobile phase is from 5 / 95 v / v to 80 / 20 v / v.

4. The method according to any one of claims 1 to 3, wherein the pH of the mobile phase is from 0 to 8.

5. A method described in any one of claims 1 to 3, wherein the pH of the mobile phase is 1 to 3.

6. The method of claim 1 , wherein the mobile phase further comprises a buffer.

7. The method of claim 6, wherein the buffer is selected from alkali metal dihydrogen phosphates, dialkali metal hydrogen phosphates, trialkali metal phosphates, alkali metal acetates, alkali metal formates and mono / di / trialkali metal citrates.

8. The method according to any one of claims 1 to 7, wherein the high performance liquid chromatography (HPLC) is carried out under a pressure of 50 to 400 bar.

9. The method of claim 1, wherein high performance liquid chromatography (HPLC) is carried out at a pressure of 50 to 250 bar.

10. 10. The method according to any one of claims 1 to 9, wherein a fraction containing the compound of formula I is obtained by high performance liquid chromatography (HPLC), and this fraction is subjected to step D) sterile filtration.

11. 11. The method according to any one of claims 1 to 10, which does not include a solid phase extraction of the compound of formula I after step C.

12. The method of claim 1, wherein the method does not include solid phase extraction of the compound of formula I before or after step C.

13. 13. The method of any one of claims 1 to 12, wherein the compound of formula I is not chromatographed after high performance liquid chromatography (HPLC) in step C.

14. The method of any one of claims 1 to 12, wherein the compound of formula I is not subjected to chromatography other than high performance liquid chromatography (HPLC) in step C.

Images