Diagnostic drugs and applications for diabetic nephropathy

Abstract

This invention provides compounds of general formula (I) or pharmaceutically acceptable salts, precursors, solvates thereof, and their use in the preparation of diagnostic drugs for diabetic nephropathy. Wherein, X is selected from carbon or nitrogen; R1 is selected from hydrogen or alkyl; R2 is one or more substituents on the benzene ring or pyridine ring, and R2 is independently selected from one or more of hydrogen, halogen, hydroxyl, cyano, nitro, amino, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C2-C6 alkoxy, C3-C6 cycloalkoxy, C1-C6 alkylamine, C3-C6 cycloalkylamine, halogenated C1-C6 alkyl, halogenated C3-C6 cycloalkyl, halogenated C1-C6 alkoxy, halogenated C3-C6 cycloalkoxy, halogenated C1-C6 alkylamine, halogenated C3-C6 cycloalkylamine, C6-C8 aryl or C5-C8 heteroaryl, and at least one atom of these substituents represented by R2 or the entire substituent is replaced by a radionuclide. The diagnostic drugs and methods for diabetic nephropathy of the present invention are non-invasive diagnostic techniques with the advantages of less discomfort for subjects and fewer contraindications.

Description

[Technical Field]

[0001] This invention relates to a diagnostic drug for diabetic nephropathy, particularly a radiotherapy drug. Specifically, it relates to the use of a triazolanotetrahydropyridine cyclic compound in the diagnosis of diabetic nephropathy and a diagnostic method for diabetic nephropathy. [Previous Technology]

[0002] Diabetic kidney disease (DKD) is a common complication of diabetes and one of the important causes of end-stage renal failure. Early diagnosis of DKD is particularly important. Generally, studies suggest that when the estimated glomerular filtration rate (eGFR) is <30 mL·min⁻¹·1.73 m⁻², renal function damage is irreversible. Early drug intervention can delay the onset of organic kidney disease. Timely detection of early glomerular, tubular, and interstitial lesions is beneficial for the early diagnosis and treatment of DKD. A retrospective study involving 121,395 subjects showed that early diagnosis of DKD can reduce the risk of subjects progressing to end-stage renal disease by 80% (Chinese Journal of Internal Medicine. 2021. 60(6): 522-532.). Since the management and treatment of DKD are quite different from those of non-diabetic kidney disease (NDKD), clinicians should accurately diagnose DKD and identify NDKD based on clinical manifestations and auxiliary examinations, so as to take timely and correct treatment for subjects. Currently, the clinical diagnosis of diabetic kidney disease (DKD) often relies on albuminuria and the presence of diabetic retinopathy. However, albuminuria lacks specificity for diagnosing DKD, and some DKD patients may present with negative urine protein in the early stages, only showing a decrease in gluconeogenesis imperfecta (GFR). Therefore, the presence of albuminuria or a decrease in GFR in diabetic patients could indicate DKD, non-diabetic kidney disease (NDKD), or both. Therefore, before diagnosing DKD, it is essential to rule out NDKD in addition to diabetes. Currently, renal biopsy is the gold standard for diagnosing DKD and ruling out NDKD. If the patient has no contraindications for renal biopsy, pathological diagnosis of DKD via renal biopsy is recommended (Expert Consensus on the Prevention and Treatment of Diabetic Nephropathy, 2014 edition). Japanese Patent Application Publication No. 2010-256132A discloses a method for detecting the progression of diabetic nephropathy, a diagnostic kit for the progression of diabetic nephropathy, and substances and methods used as indicators of the progression of diabetic nephropathy. In this patent application, bodily fluids collected from a subject are reacted with lectins to measure the amount of glycans with affinity for the lectins, and the measured amount of glycans is used to detect the progression of diabetic nephropathy. International patent application WO2020071517 discloses biomarkers miRNA-125b-5p and / or miRNA-181b-5p that can specifically diagnose diabetic nephropathy. In this diagnosis, diabetic nephropathy is diagnosed when the expression of miRNA-125b-5p in the blood increases and / or the expression of miRNA-181b-5p decreases. [Summary of the Invention]

[0003] The technical problem to be solved by the present invention is as described above. Currently, the effective method for diagnosing diabetic nephropathy is renal biopsy. However, renal biopsy is an invasive procedure, and it also requires exclusion of contraindications such as significant bleeding tendency, severe hypertension, mental illness or non-cooperative patients, solitary kidney, and small kidney. Therefore, renal biopsy has certain limitations.

[0004] In view of the limitations of the prior art, the purpose of the present invention is to provide a non-invasive and contraindicated diagnostic drug and method for diabetic nephropathy.

[0005] Technical solutions to address technical problems

[0006] The inventors sought compounds that specifically accumulate in the kidneys of subjects with diabetic nephropathy. Among the compounds described in International Publication No. WO2014 / 152604A1, which discloses an affinity for the P2X7 receptor (P2X7R), the inventors discovered that compounds of the following general formula (I) possess the characteristic of specific accumulation in the kidneys of subjects / models with diabetic nephropathy. This invention utilizes radionuclide labeling of the aforementioned compounds and positron emission tomography (PET) or single-photon emission computed tomography (SPECT) imaging techniques to locate and quantify the aforementioned compounds accumulated in the kidneys for the purpose of diagnosing diabetic nephropathy.

[0007] Specifically, the present invention includes the following technical solutions.

[0008] A compound of general formula (I) or a pharmaceutically acceptable salt, precursor or solvate thereof, wherein (I) X is selected from carbon (C) or nitrogen (N); R1 is selected from hydrogen or alkyl; R2 is one or more substituents on a benzene ring or pyridine ring, and R2 is independently selected from one or more of hydrogen, halogen, hydroxyl, cyano, nitro, amino, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C2-C6 alkoxy, C3-C6 cycloalkoxy, C1-C6 alkylamine, C3-C6 cycloalkylamine, C1-C6 hydroxyalkyl, C3-C6 hydroxycycloalkyl, halo-C1-C6 alkyl, halo-C3-C6 cycloalkyl, halo-C1-C6 alkoxy, halo-C3-C6 cycloalkoxy, halo-C1-C6 alkylamine, halo-C3-C6 cycloalkylamine, C6-C8 aryl, or C5-C8 heteroaryl, and at least one atom of these substituents represented by R2 or the entire substituent is replaced by a radionuclide.

[0009] In the compound of general formula (I), R1 is preferably hydrogen, C1-C6 alkyl or C3-C6 cycloalkyl.

[0010] In the compound of general formula (I), R2 is one or more substituents on the benzene ring or pyridine ring, for example, it can be 1, 2, 3, 4 or 5 substituents. When there are more than 2 substituents, these substituents can be the same or different.

[0011] R2 is further preferably one or more of hydrogen, halogen, hydroxyl, nitro, amino, C1-C4 alkyl, C1-C4 alkoxy, C1-C4 alkylamine, halo-C1-C4 alkyl, halo-C1-C4 alkoxy or halo-C1-C4 alkylamine, and at least one atom or the entire group of these substituents is replaced by a radionuclide.

[0012] In the compound of general formula (I), the radionuclide is preferably one or more of 18F, 11C, 131I, 123I, 124I, and 125I.

[0013] The compound of general formula (I) is preferably selected from any one of the following compounds: 18F-KIDJI-003 (S)-(3-fluoro-2-trifluoromethylpyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, 18F-KIDJI-004 (S)-(2-fluoro-6-methylpyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, 131I-KIDJI-007 (4-Iodophenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, 131I-KIDJI-008 (3-Iodo-4-methoxyphenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, 131I-KIDJI-009 (2-Iodo-4-nitro)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, (2-Fluoro-4-(tri-n-butyltin)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, 131I-KIDJI-010 (2-Fluoro-4-iodophenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone.

[0014] The precursor compound is selected from: KIDJI-003 precursor (S)-(3-chloro-2-trifluoromethylpyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, KIDJI-004 precursor (S)-(2-chloro-6-methylpyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, KIDJI-007 precursor (1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, KIDJI-007 precursor (1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) Pyridin-5-yl)(4-tri-n-butyltinphenyl) methyl ketone, KIDJI-008 precursor (4-methoxy-3-(tri-n-butyltin)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, KIDJI-009 precursor (4-nitro-2-(tri-n-butyltin)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone, KIDJI-010 precursor (2-fluoro-4-(tri-n-butyltin)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3] Triazolo[4,5-c]pyridin-5-yl)methyl ketone.

[0015] The pharmaceutically acceptable salts of the compounds of the present invention are addition salts of inorganic acids or organic acids. The inorganic acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, and nitric acid, and the organic acid is selected from acetic acid, tartaric acid, salicylic acid, methanesulfonic acid, succinic acid, citric acid, malic acid (i.e., 2-hydroxysuccinic acid), lactic acid, and fumaric acid.

[0016] The solvate of the compound of the present invention is preferably a hydrate.

[0017] The present invention also provides the use of any of the above-mentioned compounds or pharmaceutically acceptable salts, precursors or solvates thereof in the preparation of diagnostic medicaments for diabetic nephropathy.

[0018] The present invention also provides a radioactive diagnostic kit for diagnosing diabetic nephropathy, wherein the radioactive diagnostic reagent comprises a compound having the structure shown in the above general formula (I) or a pharmaceutically acceptable salt, precursor or solvate thereof.

[0019] In the diagnostic kit of the present invention, the pharmaceutically acceptable salt is an addition salt of an inorganic acid or an organic acid. The inorganic acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, and nitric acid; the organic acid is selected from acetic acid, tartaric acid, salicylic acid, methanesulfonic acid, succinic acid, citric acid, malic acid (i.e., 2-hydroxysuccinic acid), lactic acid, and fumaric acid.

[0020] In the diagnostic kit of the present invention, the solvate is a hydrate.

[0021] The present invention also provides a method for diagnosing diabetic nephropathy, comprising: preparing a physiologically acceptable solution of any of the compounds described above, or pharmaceutically acceptable salts, precursors, or solvates thereof; introducing the solution into a subject; imaging the kidneys of the subject; analyzing the images; and making a diagnosis based on the analysis results.

[0022] Of the above diagnostic methods, imaging via PET or SPECT is preferred.

[0023] In the above diagnostic method, the physiologically acceptable solution can be introduced into the subject's body by means of, for example, injection.

[0024] Technical Effects This invention provides a radiodiagnostic drug, its application in the diagnosis of diabetic nephropathy, and a method for diagnosing diabetic nephropathy. By intravenously injecting the radiodiagnostic drug followed by PET or SPECT imaging, non-invasive diagnosis of diabetic nephropathy can be achieved. Compared with conventional invasive renal biopsy, it has the advantages of less patient discomfort and fewer contraindications.

Implementation Method

[0026] The features, characteristics, compounds, chemical parts, or groups described in connection with embodiments or examples of the present invention should be understood to be applicable to any other embodiments or examples described herein, unless incompatible therewith. All features disclosed in this specification (including the claims, abstract, and drawings of the patent application) and / or all steps of any method or process disclosed therefrom may be combined in any manner, except for at least some mutually exclusive combinations of such features and / or steps. The invention is not limited to the details of any embodiment. The invention extends to any new feature or any new combination of features disclosed in this specification (including the claims, abstract, and drawings of the patent application), or to any new step or any new combination of steps of any method or process disclosed therefrom.

[0027] Imaging Isotopes and Imaging: Diagnostic techniques in nuclear medicine use radioactive tracers that emit gamma rays from within the body. These tracers are typically short-lived isotopes linked to compounds, allowing for detailed examination of specific physiological processes. They can be administered via injection, inhalation, or oral administration. One method involves a gamma camera that detects single photons, allowing observation of organs from many different angles. The camera creates an image based on the point of emission; this image is computer-enhanced, and doctors view it on a monitor for signs of abnormalities.

[0028] Positron emission tomography (PET) is a precise and sophisticated technique that uses isotopes produced by a cyclotron. The positron-emitting radionuclide is typically introduced via injection and accumulates in the target tissue. When the radionuclide decays, it emits positrons, which rapidly combine with nearby electrons, resulting in the simultaneous emission of two identifiable gamma rays in opposite directions. These are detected by a PET camera and their origin is indicated very precisely. PET's most important clinical application is in oncology, using fluoro-18-fluorodeoxyglucose ([18F]FDG) as a tracer, as it has proven to be the most accurate non-invasive method for detecting and evaluating most cancers. It is also well-suited for cardiac and brain imaging.

[0029] It is well known in the art that many medical diagnostic procedures (including PET and SPECT) utilize radiolabeled compounds. PET and SPECT are highly sensitive techniques and require small amounts of radiolabeled compounds (called tracers). Radiolabeled compounds are transported, accumulated, and transformed in the body in a similar manner to their corresponding non-radiolabeled compounds. Tracers or probes may be radiolabeled using radionuclides useful for PET imaging, such as 11C, 13N, 15O, 18F, 64Cu, and 124I, or using radionuclides useful for SPECT imaging, such as 99Tc, 77Br, 61Cu, 153Gd, 123I, 125I, 131I, and 32P. These are non-limiting examples of the term "radionium" (also known as a radioisotope or imaging isotope) as used herein.

[0030] Regarding radioactive halogens, the isotope 123I has a half-life of 13 hours and a gamma energy of 159 keV, therefore it is commonly used to label ligands intended for diagnostic purposes with this isotope or 18F (half-life of 2 hours). Other imaging isotopes that can be used include 131I, 77Br, and 76Br.

[0031] Those skilled in the art to which this invention pertains are familiar with various methods of detecting labeled compounds for imaging purposes. For example, positron emission tomography (PET) or single-photon emission computed tomography (SPECT) can be used to detect radiolabeled compounds. The label introduced into the compound may depend on the desired detection method. Those skilled in the art to which this invention pertains are familiar with PET detection of positron-emitting atoms such as 18F. Those skilled in the art to which this invention pertains are familiar with SPECT detection of photon-emitting atoms such as 123I or 99Tc.

[0032] Radioactive diagnostic or detection reagents should have sufficiently high radioactivity and concentration to ensure reliable diagnosis and detection. The required level of radioactivity can be obtained through the methods for preparing the compounds provided herein.

[0033] Typically, in the first step of an imaging method, a labeled compound is introduced into a tissue or subject in a detectable amount. This compound is usually part of a pharmaceutical composition and is administered to the tissue or subject by methods well known to those skilled in the art to which this invention pertains. Typically, administration is by intravenous injection.

[0034] In other embodiments of the invention, the labeled compound is introduced into the subject in a detectable amount, and after sufficient time has been allowed for the compound to accumulate in the kidneys, the labeled compound is detected non-invasively.

[0035] The detectable amount is the amount of labeled compound necessary for detection by the selected detection method. The amount of labeled compound to be introduced into the subject to provide detectable results can be readily determined by those skilled in the art to which this invention pertains. For example, the amount of labeled compound given to the subject can be continuously increased until the compound is detected using the selected detection method. A radionuclide is introduced into the compound to provide detection of the compound.

[0036] By introducing a detectable amount of the labeled compound into the subject and then detecting the labeled compound at different times after administration, the required time amount can be easily determined.

[0037] The radiolabeled compound can be administered to the subject via a general or local administration route. For example, the labeled compound can be administered to the subject so that the compound is delivered throughout the body. Alternatively, the labeled compound can be administered to a specific target organ or tissue. For example, it may be desirable to locate and quantify the levels of the labeled compound in the kidneys in order to diagnose or track the progression of diabetic nephropathy in the subject.

[0038] One or more radionuclides can be incorporated into the compounds disclosed herein by replacing one or more atoms (e.g., hydrogen or alkyl, halogen, etc.) in a compound with an affinity for the P2X7 acceptor (P2X7R) as described in prior art WO2014 / 152604A1 with a radionuclide. The incorporation of radionuclides can be performed using known techniques. For example, these techniques can be based on the nucleophilic or electrophilic 18F fluorination of a suitable precursor, as described in, for example, the following literature: Medicinal Chemistry Approaches to Personalized Medicine (Lackey, Roth, ed.), Chapter 12 (Wiley-VCH, ISBN 978-3-527-33394-3).

[0039] In the embodiments of this invention, unless otherwise specified, all instruments, raw material components, experimental animals, and chemical reagents are commercially available products well known to those skilled in the art. In the embodiments of this invention, unless specifically specified, all technical means used are conventional means well known to those skilled in the art. The reaction process of this invention can be monitored using conventional monitoring methods in the art (e.g., TLC, HPLC, LCMS, or NMR), and the reaction endpoint is generally defined as the disappearance of the reaction matrix.

[0040] Experimental methods not specifically described in the embodiments of the specification are generally performed under conventional conditions in the art or under conditions recommended by the manufacturer. In this invention, unless otherwise specified, "above," "below," and "within" indicate inclusion of the stated number. When embodiments are described herein using "comprising" or "including," other similar embodiments described as "consisting of" and / or "substantially consisting of" are also provided. When embodiments are described herein using "substantially consisting of," other similar embodiments described as "consisting of" are also provided. The term "and / or" as used in phrases such as "A and / or B" is intended to include both A and B; A or B; A (alone); and B (alone). Similarly, the term "and / or" as used in phrases such as "A, B, and / or C" is intended to include each of the following embodiments: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0041] In this invention, the term "C1-C6 alkyl" refers to a straight-chain or branched alkyl group having 1 to 6 carbon atoms in its chain. Examples include methyl (Me), ethyl (Et), n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl (tBu), n-pentyl, isopentyl (2-methylbutyl), neopentyl (2,2-dimethylpropyl), n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,3-dimethylbutyl, 2,4-dimethylbutyl, 3,3-dimethylbutyl, 2-ethylbutyl, etc., and groups that would be considered equivalent to any of the foregoing examples based on ordinary skill in the art and the teachings provided herein. Similarly, the term "C1-C4 alkyl" refers to a straight-chain or branched alkyl group having 1 to 4 carbon atoms in its chain.

[0042] The term "C3-C6 cycloalkyl" refers to a saturated monocyclic or polycyclic carbon ring having 3 to 6 carbon atoms, such as cyclopropyl, 1-methylcyclopropyl, cyclobutyl, cyclopentyl, 1-methylcyclobutyl, cyclohexyl, 1,3-dimethylcyclobutyl, 1-methylcyclopentyl, and groups that, based on ordinary skill in the art and the teachings provided herein, would be considered equivalent to any of the foregoing examples.

[0043] The term "C2-C6 alkenyl" refers to a group having 2 to 6 carbon atoms and containing at least one carbon-carbon double bond, and may be straight-chain or branched. The group may contain multiple double bonds, and the orientation of each double bond is independently E or Z. The alkenyl group is preferably 1-alkenyl. Exemplary alkenyl groups include, but are not limited to, vinyl, propenyl, butenyl, pentenyl, hexenyl, and groups that, based on ordinary skill in the art and the teachings provided herein, would be considered equivalent to any of the foregoing examples. The group may be a terminal group or a bridging group.

[0044] The term "C2-C6 ynyl" refers to a group having 2 to 6 carbon atoms and containing at least one carbon-carbon triple bond, and may be straight-chain or branched. The group may contain multiple triple bonds. The ynyl group is preferably 1-ynyl. Exemplary ynyl groups include, but are not limited to, ethynyl, propynyl, butynyl, pentyynyl, hexynyl, and groups that, based on ordinary skill in the art and the teachings provided herein, would be considered equivalent to any of the foregoing examples. The group may be a terminal group or a bridging group.

[0045] The term "C1-C6 alkoxy" refers to a C1-C6 alkyl-O- group, wherein the C1-C6 alkyl group is as defined above. The group may be a terminal group or a bridging group. Specifically, C1-C6 alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentoxy (e.g., 2-methylbutoxy, 2-methoxybutyl), neopentoxy (e.g., 2,2-dimethylpropoxy), cyclopentoxy, n-hexyloxy, 2-methylpentoxy, 2-methoxypentyl, 3-methylpentoxy, 3-methoxypentyl, 2,3-dimethylbutoxy, 2,4-dimethylbutoxy, 3,3-dimethylbutoxy, 2,3-dimethoxybutyl, 2,4-dimethoxybutyl, 3,3-dimethoxybutyl, 2-ethylbutoxy, 2-ethoxybutyl, etc., and groups that, based on ordinary skill in the art and the teachings provided herein, would be considered equivalent to any of the foregoing examples.

[0046] The term "C1-C6 alkylamine" refers to an NH2-alkyl (C1-C6) group, wherein the alkyl (C1-C6) is as defined herein as C1-C6 alkyl. The group may be a terminal group or a bridging group. If the group is a terminal group, the group is bonded to the remainder of the molecule through the alkyl group.

[0047] The term "halogen" means fluorine, chlorine, bromine or iodine.

[0048] The term "halogenated C1-C6 alkyl" refers to a C1-C6 alkyl group in which hydrogen is optionally replaced by a halogen. The definition of C1-C6 alkyl is the same as above. Examples include, but are not limited to, trifluoromethyl (CF3), difluoromethyl (CF2H), monofluoromethyl (CH2F), pentafluoroethyl (CF2CF3), tetrafluoroethyl (CHFCF3), monofluoroethyl (CH2CH2F), trifluoroethyl (CH2CF3), tetrafluorotrifluoromethylethyl (-CF(CF3)2), and groups that, based on ordinary skill in the art and the teachings provided herein, would be considered equivalent to any of the foregoing examples.

[0049] The term "C1-C6 haloalkoxy" refers to a C1-C6 alkoxy group in which hydrogen is optionally replaced by a halogen. The definition of C1-C6 alkoxy is the same as above. Examples of haloalkoxy groups include trifluoromethoxy (OCF3), difluoromethoxy (OCF2H), monofluoromethoxy (OCH2F), monofluoroethoxy (OCH2CH2F), pentafluoroethoxy (OCF2CF3), tetrafluoroethoxy (OCHFCF3), trifluoroethoxy (OCH2CF3), tetrafluorotrifluoromethylethoxy (-OCF(CF3)2), and groups that, based on ordinary skill in the art and the teachings provided herein, would be considered equivalent to any of the foregoing examples.

[0050] The term "C1-C6 haloalkylamine" refers to a C1-C6 alkylamine group in which hydrogen is optionally replaced by a halogen. The definition of C1-C6 alkylamine is the same as above.

[0051] The term "C6-C8 aryl" refers to an aromatic carbon ring having a ring structure in which all ring atoms are carbon atoms, preferably having 6 to 8 carbon atoms per ring. Examples of aryl groups include phenyl groups. The group can be a terminal group or a bridging group.

[0052] The term "C5-C8 heteroaryl" refers to a group containing an aromatic ring (preferably a 5- or 6-membered aromatic ring), wherein the aromatic ring has one or more heteroatoms as ring atoms in the aromatic ring, and the remaining ring atoms are carbon atoms. Suitable heteroatoms include nitrogen, oxygen and sulfur. Examples of heteroaryl groups include thiophene, furan, imidazole, thiazole, isothiazole, [2,3-b]thiophene, isoindazine, pyrrole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, tetrazolium, indole, isoindole, 1H-indazole, purine, quinoline, isoquinoline, phthalazine, naphthidine, quinoxaline, zoline, zopyrazole, phenanthridine, acridine, phenazine, isothiazole, phenothiazine, oxazole, isoxazole, furazine, phenothiazine, 2-pyridyl, 3-pyridyl or 4-pyridyl, 2-quinolinyl, 3-quinolinyl, 4-quinolinyl, 5-quinolinyl or 8-quinolinyl, 1-isoquinolinyl, 3-isoquinolinyl, 4-isoquinolinyl or 5-isoquinolinyl, 1-indole, 2-indole or 3-indole, and 2-thienyl or 3-thienyl. The group can be a terminal group or a bridging group.

[0053] The term "substitution" means that a specified group or portion has one or more substituents. The term "optionally substituted" means that a particular group is unsubstituted or substituted by one or more substituents. If the term "substitution" is used to describe a structural system, it means that substitution occurs at any position permitted by any valence in that system. Where a specified portion or group is not explicitly indicated to be optionally substituted or replaced by any specified substituent, it should be understood that such portion or group is intended to indicate that it is unsubstituted. The terms "one or more" and "one or more" used with respect to substituents refer to the highest chemically possible number of substitutions, i.e., replacing one atom with its corresponding radioactive isotope, until all atoms are substituted.

[0054] The term "diagnosis" refers to the act of identifying a disease from its signs and symptoms. In this invention, it specifically refers to the analysis of biomarkers that indicate a disease.

[0055] The term "subject" includes both humans and non-human animals. Non-human animals include all vertebrates, such as mammals and non-mammals, such as non-human primates, sheep, dogs, cattle, chickens, amphibians, and reptiles. Unless otherwise indicated, the terms "patient" or "subject" are used interchangeably herein.

[0056] The term “P2X7R” refers to the P2X7 receptor.

[0057] The term "pharmaceutically acceptable" means a product or compound approved by the Chinese drug regulatory authority or listed in the Chinese Pharmacopoeia or other recognized pharmacopoeias for use in animals, including humans.

[0058] The "precursor" described in this invention is a chemical substance preceding the formation of a compound of formula (I). This chemical substance can generate a radiolabeled compound of formula (I) through a radiolabeling chemical reaction.

[0059] Compounds of general formula (I) can form addition salts with suitable nontoxic organic or inorganic acids. Examples of acid addition salts include salts derived from inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, and nitric acid, and salts derived from organic acids such as acetic acid, tartaric acid, salicylic acid, methanesulfonic acid, succinic acid, citric acid, malic acid, lactic acid, fumaric acid, etc. These salts can be prepared from compounds of general formula (I) according to known salt-forming methods.

[0060] The compounds of the present invention can be recovered from the reaction mixture and purified in a conventional manner. Isomers, such as enantiomers, can be obtained in a conventional manner, for example, by stepwise synthesis from starting materials with corresponding asymmetric substitutions. If desired, protection of any active group can be carried out in any suitable step. Protecting groups are suitable to be protecting groups conventionally used in the art, and can be introduced and removed by conventional methods. For example, when an amino group is protected by a Boc, the Boc can be removed by conventional methods under acidic conditions.

[0061] The compounds of the present invention can be synthesized according to known techniques. The present invention will be described in detail below with reference to the embodiments.

[0062] Example 1: Preparation method of the precursor compound of the present invention. The precursor compound of the present invention was prepared according to the following flowchart.

[0063] Example 1-1: Synthesis of (S)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (KIDJI-003 precursor)

[0064] Step 1. Synthesis of Compound 2: 2-Chloropyrimidine (10.0 g, 1.0 eq) was placed in a 100 mL three-necked flask under N2 protection and the temperature was controlled at T≤30℃. Hydrazine hydrate (20 mL, 4.7 eq) was slowly added dropwise. The mixture was stirred overnight at room temperature for 16 h. TLC monitoring showed that the reaction of the starting material was complete (pure ethyl acetate, product polarity increased). The mixture was concentrated under reduced pressure to dryness, and n-hexane (50 mL) was added and stirred for 2 h. The mixture was filtered, and the filter cake was washed with n-hexane (20 mL). The solid was concentrated to dryness and dried by an oil pump to give 7.7 g of white solid, yield 80%.

[0065] Step 2. Synthesis of Compound 3: Compound 2 (5 g, 1.0 eq) was placed in a 250 ml three-necked flask under N2 protection. 100 mL of 50% glacial acetic acid aqueous solution was added. The temperature was lowered to below 0°C. 25 mL of water solution containing sodium nitrite (6.3 g, 2.0 eq) was slowly added dropwise while maintaining the temperature T≤5°C. The addition was completed over half an hour. The reaction was carried out at 0°C for about 2 hours. The reaction was monitored by TLC until the starting material was completely reacted. Sodium carbonate solid was slowly added to adjust the pH to about 8. The mixture was extracted three times with toluene. The organic layer was collected, dried, filtered, and used directly in the next step of the reaction without concentration.

[0066] Step 3. Synthesis of Compound 4: Compound 3 (0.7 g, 1.0 eq) and (S)-2-methyl-4-oxopiidine-1-carboxylic acid tert-butyl ester (0.95 g, 0.77 eq) were placed in a 100 mL three-necked flask, toluene (10 mL) was added, and the mixture was heated to 70 °C under N2 protection. Tetrahydropyrrole (0.316 g, 0.77 mmol) was injected using a syringe, and the mixture was heated to 100 °C. The reaction was allowed to proceed for 16 h, and TLC monitoring showed the formation of new spots. The mixture was cooled to room temperature, concentrated under reduced pressure, and purified by column chromatography (PET / EA = 1:10).

[0067] Step 4. Synthesis of Compound 5: Compound 4 (0.5 g, 1.0 eq) was placed in a 100 mL three-necked flask under N2 protection. Anhydrous dichloromethane (10 mL) was added, followed by sodium bicarbonate (0.11 g, 1.0 eq). Then, m-CPBA (0.33 g, 1.0 eq) was slowly added. The mixture was stirred at room temperature for 2 hours, and the reaction was monitored by TLC until the reactants were fully reacted. After the reaction was complete, 1N sodium hydroxide aqueous solution (10 mL) was added, and the mixture was stirred for 20 minutes. The mixture was then extracted with dichloromethane, and the organic phase was collected, dried, concentrated under reduced pressure, and used directly in the next reaction step.

[0068] Step 5. Synthesis of Compound 6: Compound 5 (1 g, 1.0 eq) was placed in a 100 mL single-necked flask under N2 protection. TFA (2.4 g, 10 eq) was added and stirred at room temperature for 16 h. The reaction of the starting material was monitored by TLC until it was completely reacted. TFA was removed by concentration under reduced pressure. Dichloromethane was added and the pH was adjusted to about 8 by adding 10% sodium carbonate aqueous solution. The mixture was extracted three times with dichloromethane. The organic phase was collected, dried, filtered, concentrated under reduced pressure, and purified by column chromatography (DCM / MeOH=15:1).

[0069] Step Six. Synthesis of (S)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (compound 7; precursor of KIDJI-003): Compound 6 (60 g, 1.0 eq) was placed in a 100 mL three-necked flask under N2 protection. Chloronicotinic acid (50 mg, 1.1 eq), HATU (91 mg, 1.1 eq), DIPEA (0.15 ml, 4.0 eq), DMF (5 ml), and DCM (10 ml) were added. The mixture was stirred at room temperature for 16 h. LCMS monitoring showed product formation. Wash with saturated brine (20 ml), extract with dichloromethane, collect the organic phase, concentrate under reduced pressure, and purify by column chromatography; then evaporate to dryness to obtain a white solid. ¹H NMR (500 MHz, Chloroform-d) δ 8.84–8.79 (m, 2H), 8.65–8.57 (m, 1H), 7.37–7.31 (m, 2H), 5.79–5.72, 5.55 (m, 1H), 4.57, 3.97–3.93 (m, 1H), 4.38–4.30 (m, 1H), 3.44–3.16 (m, 2H), 1.32–1.29, 1.18–1.16 (m, 3H).

[0070] Examples 1-2: Preparation of KIDJI-004 precursor According to the method of Example 1-1, chloronicotinic acid was replaced with 2-chloro-6-methylisonicotinic acid to prepare (S)-(2-chloro-6-methylpyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (KIDJI-004 precursor).

[0071] Examples 1-3: Following the method of Example 1-1, (S)-2-methyl-4-oxopidin-1-carboxylic acid tert-butyl ester was replaced with N-tert-butoxycarbonyl-4-piperidone; chloronicotinic acid was replaced with 3-n-butyltin benzoic acid to prepare (1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl)(4-tri-n-butyltin)phenyl) methyl ketone (KIDJI-007 precursor).

[0072] Examples 1-4: Following the method of Example 1-1, (S)-2-methyl-4-oxopidin-1-carboxylic acid tert-butyl ester was replaced with N-tert-butoxycarbonyl-4-piperidone; chloronicotinic acid was replaced with 3-n-butyltin-4-methoxybenzoic acid to prepare (4-methoxy-3-(tri-n-butyltin)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (KIDJI-008 precursor).

[0073] Examples 1-5: Following the method of Example 1-1, (S)-2-methyl-4-oxopidin-1-carboxylic acid tert-butyl ester was replaced with N-tert-butoxycarbonyl-4-piperidone; chloronicotinic acid was replaced with 2-n-butyltin-4-nitrobenzoic acid to prepare (4-nitro-2-(tri-n-butyltin)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (KIDJI-009 precursor).

[0074] Examples 1-6: Following a method similar to Example 1-1, (S)-2-methyl-4-oxopidin-1-carboxylic acid tert-butyl ester was replaced with N-tert-butoxycarbonyl-4-piperidone; chloronicotinic acid was replaced with 2-fluoro-4-n-butyltinylbenzoic acid to prepare (2-fluoro-4-(tri-n-butyltinyl)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (KIDJI-010 precursor).

[0075] Example 2: Label Synthesis

[0076] Labeled Synthesis Example 2-1: Labeled Synthesis of 18F-labeled (S)-(3-fluoro-2-(trifluoromethyl)pyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (18F-KIDJI-003)

[0077] 18F-labeled (S)-(3-fluoro-2-(trifluoromethyl)pyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (compound 7, KIDJI-003 precursor) was prepared using (S)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (18F-KIDJI-003) as a labeled precursor.

[0078] Weigh 5 mg of amine polyether (kryptofix) 222 and 3 mg of K2CO3 into a 1.5 mL EP tube, add 100 µL of pure water and 400 µL of acetonitrile to prepare a kryptofix-222 / K2CO3 solution. Elute 18F- with a QMA column and transfer the solution to a 3 mL conical-bottom fluorination reaction tube. Heat at 135 °C and purge with nitrogen for 3-5 minutes to dry. Add 300 µL of anhydrous acetonitrile to the fluorination reaction tube, heat at 135 °C and purge with nitrogen for 2 minutes. Repeat three times to ensure thorough dehydration and drying.

[0079] Compound 7 (2 mg) was dissolved in anhydrous DMSO (200 µL), and 4 µL of KF (potassium fluoride) solution (1.5 mg / mL DMSO) was added. This mixture was added to a reaction tube and stirred at 135 °C for 10 minutes. After the reaction was complete, the entire reaction solution was separated and purified by HPLC. HPLC was performed using a reverse-phase C18 column (Waters Atlantis T3 10×250 mm, 5 μm); the mobile phase was CH3CN / H2O (0.1% TFA) = 36:64; the flow rate was 2.0 mL / min. Fractions with a retention time of 37-38 minutes were collected, and the fraction containing the labeled compound was transferred to a 20 mL rotary evaporator flask and concentrated under reduced pressure until dried in the rotary evaporator flask. Physiological saline (containing 2.5% (V / V) Tween 80 and 2.5% (V / V) ascorbic acid solution) was added to prepare 18F-KIDJI003 injection. Radiochemical purity >95%. Mole activity is 61-87 GBq / µmol. ¹H NMR (500 MHz, Chloroform-d) δ 8.95-8.91 (m, 2H), 8.68-8.64 (m, 1H), 7.60-7.56 (m, 1H), 7.49-7.44 (m, 1H), 5.82, 5.65-5.62 (m, 1H), 4.69, 4.19-4.16 (m, 1H), 4.58-4.40 (m, 1H), 3.58-3.37 (m, 2H), 1.42-1.28 (m, 3H).

[0080] Labeling Synthesis Example 2-2: 18F-labeled (S)-(2-fluoro-6-methylpyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (18F-KIDJI-004) was prepared according to a similar method as in Labeling Synthesis Example 2-1, using a (S)-(2-fluoro-6-methylpyridin-4-yl)(6-methyl-1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone labeled precursor. Radiochemical purity > 95%. Molar activity 58-90 GBq / µmol.

[0081] Labeling Synthesis Examples 2-3: 131I-labeled (4-iodophenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (131I-KIDJI-007) was synthesized according to the following route, using (1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl)(4-tri-n-butyltin)phenyl) methyl ketone as the labeling precursor to prepare 131I-KIDJI007.

[0082] 65 µL of phosphate buffer (0.3M, pH=5.5) was placed in a 1.5 mL low-adsorption reaction tube, 20 µL of labeled precursor (1 mg / mL methanol) was added, 5 μL of 131I-NaI (200 μCi, Xinke Pharmaceutical) was added, and 5 μL of chloramine T (0.4 mg / mL H2O) was added. The reaction was vortexed at room temperature for 3 minutes, and 100 μL of Na2S2O5 (2.0 mg / mL H2O) was added to quench the reaction. The product was purified by high performance liquid chromatography (chromatographic column, CAPCELLPAK C18 UG120 (φ6.0 mm × 150 mm; Shiseido, Tokyo, Japan); mobile phase, CH3CN / H2O, 10 / 90~100 / 0, v / v; flow rate, 1.0 mL / min), and the radioactive product was collected at the corresponding time points. Repeat the above process until sufficient radiopharmaceutical (1.2-3 mCi) is collected. Concentrate under reduced pressure until dry, then add physiological saline (containing 2.5% (v / v) Tween 80 and 2.5% (v / v) ascorbic acid solution) to prepare a radiolabeled product injection solution. The radiochemical purity should be not less than 95%.

[0083] Labeling Synthesis Examples 2-4: 131I-labeled (3-iodo-4-methoxyphenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (131I-KIDJI-008) was prepared according to the method of Labeling Synthesis Examples 2-3, using (4-methoxy-3-(tri-n-butyltinyl)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone as the labeling precursor, with a radiochemical purity >95%.

[0084] Labeling Synthesis Examples 2-5: 131I-labeled (2-iodo-4-nitro)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (131I-KIDJI-009) was prepared according to the method in Labeling Synthesis Examples 2-3, using (4-nitro-2-(tri-n-butyltin)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone as the labeling precursor. Radiochemical purity > 95%.

[0085] Labeling Synthesis Examples 2-6: 131I-labeled (2-fluoro-4-iodophenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone (131I-KIDJI-010) was prepared according to the method of Labeling Synthesis Examples 2-3, using (2-fluoro-4-(tri-n-butyltinyl)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl) methyl ketone as the labeling precursor, with a radiochemical purity >95%.

[0086] Example 3: 18F-KIDJI-003 ex vivo autoradiography. The spontaneous type 2 diabetes mouse model used was the db / db homozygous mouse (BKS.Cg-Dock7m+ / +LeprdbJ; JAX® Mice Strain Code 607) discovered by the Jackson Laboratory in the United States. A defect in the leptin receptor gene on chromosome 4 causes db / db mice to exhibit overeating and obesity from four weeks of age, followed by significant hyperglycemia, hyperlipidemia, and insulin resistance with increasing age. The pathogenesis is very similar to that of type 2 diabetes patients. Control mice included normal mice (m / m) or heterozygous mice (m / db).

[0087] Mice were anesthetized with 1.5% (v / v) isoflurane and then injected with 18F-KIDJI-003 (15 MBq) via the tail vein. Sixty minutes later, the mice were euthanized by dislocation, and the kidneys were harvested and rapidly frozen in dry ice. 20 µm frozen sections were prepared using a cryostat (RWD Minux FS800). The frozen sections were in contact with a contrast plate (FUJIFILM; BAS-IP SR 2025E) for 2 hours, and images were read and quantitatively analyzed using an autoradiography scanner (CR-35 Bio; Elysia-Raytest).

[0088] Figure 1 shows ex vivo autoradiography. Compared with normal mice, 18F-KIDJI-003 showed significant accumulation in the renal pelvis of diabetic nephropathy mice. Quantitative analysis (Figure 2) showed that the radioactivity of 18F-KIDJI-003 in the renal pelvis of diabetic nephropathy mice was more than four times that in the renal pelvis of normal mice. Data were obtained from the left and right kidneys of two normal mice and two diabetic nephropathy mice, a total of four kidneys in each group.

[0089] Example 4: Live Imaging Example 4-1: PET Live Imaging of 18F-KIDJI-004

[0090] PET scans were performed using an Inveon scanner (Siemens Medical Solutions Knoxville, TN, USA). Mice (m / m and db / db mice) were anesthetized with 1.5% (v / v) isoflurane and then fixed in the center of the FOV of the PET scanner. Immediately after intravenous injection of 18F-KIDJI-004 (15 MBq), 90 minutes of radiation signal were acquired in three-dimensional mode. The energy window was 350–750 keV. After the PET scan, mice were intravenously injected with iodofol (35%) (Optiray 350; Guerbet) at 5 μL / g body weight, followed immediately by a 30-second CT scan (X-ray source: 70 kV / 88 mA, FOV: 60 mm). Mice were anesthetized with 1.5% (v / v) isoflurane during both the PET and CT scans.

[0091] In vivo imaging example 4-2: SPECT in vivo imaging with 131I-KIDJI-007. SPECT scans were performed using a nanoScan SPECT / CT scanner (Mediso Medical Imaging Systems, Hungary). Mice were anesthetized with 1.5%-2.0% (v / v) isoflurane and placed on a preheated scanning mouse bed. 131I-KIDJI-007 (11.1 MBq) was injected via the tail vein, and radiation signals were immediately acquired in three-dimensional mode every 30 minutes for up to 2 hours. The energy window was set to 360-700 keV. After completing the SPECT scan, mice were injected with iodofol (Optiray 350; Guerbet) via the tail vein at a dose of 5 μL / g body weight, followed immediately by a 30-second CT scan (X-ray source: 50 kV / 980 μA, 480 projections; mice were anesthetized with 1.5% (v / v) isoflurane during both the SPECT and CT scans).

[0092] Live Imaging Example 4-3: Live Imaging of 131I-KIDJI-008 Live Imaging of 131I-KIDJI-008 is performed by replacing 131I-KIDJI-007 with 131I-KIDJI-008 in a manner similar to that of Live Imaging Example 4-2.

[0093] Live Imaging Example 4-4: Live Imaging of 131I-KIDJI-009 Live Imaging of 131I-KIDJI-009 is performed by replacing 131I-KIDJI-007 with 131I-KIDJI-009 in a manner similar to that of Live Imaging Example 4-2.

[0094] Live Imaging Example 4-5: Live Imaging of 131I-KIDJI-010 Live Imaging of 131I-KIDJI-010 is performed by replacing 131I-KIDJI-007 with 131I-KIDJI-010 in a manner similar to that of Live Imaging Example 4-2.

[0095] The results of in vivo imaging Example 4 are shown in Figure 3. The imaging results show that 18F-KIDJI-004, 131I-KIDJI-007, 131I-KIDJI-008, 131I-KIDJI-009 and 131I-KIDJI-010 all showed significant accumulation in the renal pelvis of the kidneys of db / db model mice, while no significant accumulation was observed in the kidneys of normal mice.

[0096] Example 5: In vitro autoradiography of mouse kidney tissue sections. Freshly frozen kidneys from 6-month-old normal mice (m / m), heterozygous (m / db) and homozygous (db / db) diabetic nephropathy mice were prepared into 20µm thick sections. An incubation solution (final chemical concentration 5nM) was prepared by adding 18F-KIDJI-003, synthesized in Example 2-1, to 50mM Tris-HCl buffer (pH 7.4). The kidney sections were immersed in the incubation solution with or without the radiolabeled KIDJI-003 (10µM) and allowed to stand for 1 hour. Afterward, they were washed twice for 2 minutes each time with 50mM Tris-HCl buffer (pH 7.4). The sections were then incubated in a developing plate for 1 hour, and images were read and quantitatively analyzed using an autoradiography scanner (CR-35 Bio; Elysia-Raytest).

[0097] Table 1 TB Non-SB SB normal mice 72.49 13.83 58.66 Diabetic nephropathy model mice (homozygous) 54.87 14.13 40.74 Diabetic nephropathy model mouse (heterozygote) 57.56 13.09 44.47

[0098] The upper segment of Figure 4 shows the total binding (TB) of 18F-KIDJI-003 on fresh frozen kidney sections from normal mice and diabetic nephropathy mouse models. The lower segment shows the in vitro autoradiography with added unlabeled KIDJI-003, showing the non-specific binding (NSB) of 18F-KIDJI-003 on fresh frozen kidney sections from normal mice and diabetic nephropathy mouse models. TB minus NSB represents the specific binding (SB), a parameter reflecting P2X7R performance. Table 1 shows the quantitative results of Figure 4. The addition of unlabeled KIDJI-003 significantly reduced the total binding of 18F-KIDJI-003, indicating a large amount of 18F-KIDJI-003 specific binding in the mouse kidneys. However, there was no difference in specific binding per unit area in the kidneys of normal mice and diabetic nephropathy mouse models. This indicates that P2X7R performance is not increased in diabetic nephropathy mouse models. Therefore, the accumulation of 18F-KIDJI-003 in the renal pelvis of a diabetic nephropathy mouse model does not originate from the combination of 18F-KIDJI003 and P2X7R.

[0099] Example 6: Immunostaining Experiment of Mouse Kidney Tissue Sections Six-month-old normal mice (m / m), heterozygous (m / db), and homozygous (db / db) mice were euthanized by cervical dislocation. The left and right kidneys were removed and immersed in 4% PFA / PBS fixative overnight for tissue fixation. After washing with PBS, the kidneys were successively immersed in 20% sucrose / PBS solution overnight and then in 30% sucrose / PBS solution overnight for cryopreservation. The kidneys were then prepared into 10µm thick frozen sections using a cryostat (Reward). P2X7R staining was performed using anti-P2X7R (Cat #: APR-004, Alomone Labs) antibody. Kidney sections were treated in an autoclave (citric acid buffer (0.01M sodium citrate: 0.01M citric acid = 5:1), 121°C, 5 minutes), then rinsed with running water for 5 minutes. TSA blocking buffer (Perkin Elmer TSA Fluorescein System, NEL70000) was added to the kidney sections, and the sections were incubated for 1 hour. Incubation solution containing primary antibody (anti-P2X7R antibody, 1:1000) was added, and the sections were incubated overnight. The primary antibody was discarded, and the sections were washed three times with PBS for 5 minutes each time. Incubation solution containing biotin-labeled secondary antibody was added, and the sections were incubated for another 1 hour. Subsequently, the fluorescence signal was amplified using a TSA sensitization kit (TSA Fluorescein System, NEL70000; Perkin Elmer), and blocked using VECTASHILD mounting medium (H-1000, Vector Laboratories Inc.) for microscopic observation. The results are shown in Figure 5. There was no significant difference in P2X7R expression in the kidneys of 6-month-old normal mice (left), heterozygous db / m (middle), and homozygous db / db (right) diabetic nephropathy mice. This result is consistent with the experimental results in Figure 4, further demonstrating that P2X7R expression is not increased in homozygous db / db mice in the diabetic nephropathy model. Therefore, this further proves that the accumulation of 18F-KIDJI003 in the renal pelvis of the diabetic nephropathy mouse model does not originate from the binding of 18F-KIDJI003 and P2X7R.

[0100] Example 7: Diagnostic method for diabetic nephropathy In the diagnosis of DKD in subjects, the same as in animal experiments, PET or SPECT imaging is performed after intravenous injection of 18F-KIDJI003 radioactive molecular probe. Diagnostic nephropathy is based on whether the radioactive molecular probe accumulates in the renal pelvis.

[0101] Although the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Without departing from the spirit and concept of the invention, those skilled in the art can make various changes in form and detail, including some simple deductions or substitutions, all of which are also part of the invention. [Simplified Explanation of the Diagram]

[0025] Figure 1 shows ex vivo autoradiography images of 18F-KIDJI-003 in normal mice and diabetic nephropathy model mice. Figure 2 shows the quantitative analysis results of ex vivo autoradiography of 18F-KIDJI-003 in normal mice and diabetic nephropathy model mice. Figure 3 shows SPECT in vivo imaging images of the radiolabeled compounds 18F-KIDJI-004, 131I-KIDJI-007, 131I-KIDJI-008, 131I-KIDJI-009, and 131I-KIDJI-010 of the present invention in the kidneys of db / db model mice and normal mice. Figure 4 shows in vitro autoradiography images of 18F-KIDJI-003 in the kidneys of heterozygous and homozygous mice with diabetic nephropathy. Figure 5 shows the results of P2X7R immunostaining experiments on the kidneys of normal mice, heterozygous mice, and homozygous mice with diabetic nephropathy. [Biomaterial Storage]

[0103] None

Claims

1. The use of a compound or a pharmaceutically acceptable salt or solvate thereof in the preparation of a diagnostic medicament for diabetic nephropathy, said compound being a compound of general formula (I).

1. Among them, X is selected from carbon or nitrogen; R1 is selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl; R2 is one or more substituents on the benzene ring or pyridine ring, R2 is independently selected from one or more of hydrogen, halogen, cyano, nitro, C1-C4 alkyl, C1-C4 alkoxy, haloC1-C4 alkyl, and haloC1-C4 alkoxy, and at least one atom of these substituents represented by R2 is replaced by a radionuclide or R2 is a radionuclide.

2. For the purpose described in claim 1, the compound is selected from:

3. As described in claim 1, the pharmaceutically acceptable salt is an addition salt of an inorganic acid or an organic acid.

4. As claimed in claim 4, the inorganic acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid and nitric acid, and the organic acid is selected from acetic acid, tartaric acid, salicylic acid, methanesulfonic acid, succinic acid, citric acid, malic acid, lactic acid and fumaric acid.

5. As described in claim 1, the solvate is a hydrate.

6. For the purpose described in claim 1, the radionuclide is selected from one or more of 18F, 11C, 131I, 123I, 124I, and 125I.

7. A radiodiagnostic kit for diagnosing diabetic nephropathy, said radiodiagnostic kit comprising a compound having the structure shown in general formula (I) or a pharmaceutically acceptable salt or solvate thereof.

7. Among them, X is selected from carbon or nitrogen; R1 is selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl; R2 is one or more substituents on the benzene ring or pyridine ring, R2 is independently selected from one or more of hydrogen, halogen, cyano, nitro, C1-C4 alkyl, C1-C4 alkoxy, haloC1-C4 alkyl, and haloC1-C4 alkoxy, and at least one atom of these substituents represented by R2 is replaced by a radionuclide or R2 is a radionuclide.

8. The radiodiagnostic kit as described in claim 7, wherein the compound is selected from:

9. The radiodiagnostic kit as described in claim 7, wherein the pharmaceutically acceptable salt is an addition salt of an inorganic acid or an organic acid.

10. The radiodiagnostic kit as claimed in claim 7, wherein the inorganic acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid and nitric acid, and the organic acid is selected from acetic acid, tartaric acid, salicylic acid, methanesulfonic acid, succinic acid, citric acid, malic acid, lactic acid and fumaric acid.

11. The radiodiagnostic kit as described in claim 7, wherein the solvate is a hydrate.

12. The radiodiagnostic kit as described in claim 7, wherein the radionuclide is selected from one or more of 18F, 11C, 131I, 123I, 124I, and 125I.

Images