Diagnostic drugs 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 a benzene ring or pyridine ring, and R2 is independently selected from hydrogen, halogen, hydroxyl, cyano, nitro, amino, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, ... One or more of the following substituents are selected: C3-C6 cycloalkoxy, C1-C6 alkylamine, C3-C6 cycloalkamine, halogenated C1-C6 alkyl, halogenated C3-C6 cycloalkyl, halogenated C1-C6 alkoxy, halogenated C3-C6 cycloalkoxy, halogenated C1-C6 alkylamine, halogenated C3-C6 cycloalkamine, 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 drug and method for diabetic nephropathy of this invention are non-invasive diagnostic techniques, with advantages of less discomfort for the subject and fewer contraindications.

Description

Technical Field

[0001] The present invention relates to a diabetic nephropathy diagnostic drug, in particular to a radioactive therapeutic drug, specifically, to the use of a triazolotetrahydropyridine ring compound in the diagnosis of diabetic nephropathy and a method for diagnosing diabetic nephropathy. Prior Art

[0002] Diabetic nephropathy (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 have shown that when the estimated glomerular filtration rate (eGFR) is less than 30 mL·min-1·1.73 m-2, renal function damage is irreversible. Early drug intervention can delay the onset of organic renal disease. Timely detection of early glomerular, tubular and interstitial lesions is conducive to 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 non-diabetic nephropathy (NDKD), clinicians should accurately diagnose DKD and identify NDKD based on clinical manifestations and auxiliary examinations, so as to provide timely and correct treatment for subjects. At present, the diagnosis of DKD is often based on albuminuria and whether the subject has diabetic retinopathy, etc. However, albuminuria lacks specificity for diagnosing DKD, and some DKD subjects may show negative urine protein in the early stage, with only a decrease in GFR. Therefore, diabetic subjects with albuminuria or decreased GFR may be DKD, NDKD, or a combination of the two. Therefore, before diagnosing DKD, it should be ruled out whether diabetes is combined with NDKD. At present, renal biopsy is the gold standard for diagnosing DKD and excluding NDKD. If the subject has no contraindications to renal biopsy, renal biopsy is recommended for pathological diagnosis of DKD (Expert Consensus on Prevention and Treatment of Diabetic Nephropathy, 2014 Edition). Japanese Patent Application Laid-Open No. 2010-256132A discloses a method for detecting the degree of progression of diabetic nephropathy, a diagnostic kit for the degree of progression of diabetic nephropathy, and a substance and method as an indicator of the degree of progression of diabetic nephropathy. In this patent application, the body fluid collected from the subject is reacted with lectin to measure the amount of sugar chains with affinity to the lectin, and the measured amount of sugar chains is used to detect the progression of diabetic nephropathy. International patent application WO2020071517 discloses a biomarker miRNA-125b-5p and / or miRNA-181b-5p that can specifically diagnose diabetic nephropathy. In this diagnosis, when the expression of miRNA-125b-5p in the blood increases and / or the expression of miRNA-181b-5p decreases, diabetic nephropathy is diagnosed. Summary of the invention

[0003] Technical Problems to be Solved by the Invention As mentioned above, the current effective method for diagnosing diabetic nephropathy is renal biopsy. However, renal biopsy is a traumatic examination. Moreover, renal biopsy must exclude contraindications such as obvious bleeding tendency, severe hypertension, mental illness or non-cooperation, solitary kidney, small kidney, etc. Therefore, renal biopsy has certain limitations.

[0004] In view of the limitations of conventional technology, the purpose of the present invention is to provide a non-invasive and contraindication-free drug and method for diagnosing diabetic nephropathy.

[0005] Technical solutions to solve technical problems

[0006] The inventors searched for compounds that specifically accumulate in the kidneys of diabetic nephropathy subjects. Among the compounds described in the international publication No. WO2014 / 152604A1 that discloses affinity for P2X7 receptors (P2X7R), the inventors found that the compound of the following general formula (I) has the characteristic of specifically accumulating in the kidneys of diabetic nephropathy subjects / models. The present invention uses radionuclide labeling of the above-mentioned compounds and positron emission tomography (PET) or single photon emission computed tomography (SPECT) imaging technology to locate and quantify the above-mentioned compounds accumulated in the kidneys to achieve the purpose of diagnosing diabetic nephropathy.

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

[0008] A compound represented by general formula (I) or a pharmaceutically acceptable salt, precursor or solvate thereof, (I) Wherein, X is selected from carbon (C) or nitrogen (N); R 1 is selected from hydrogen or alkyl; R2 is one or more substituents on the benzene ring or the 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 alkynyl, C1-C6 alkoxy, C3-C6 cycloalkyloxy, C1-C6 alkylamino, C3-C6 cycloalkylamino, C1-C6 hydroxyalkyl, C3-C6 hydroxycycloalkyl, halogenated C1-C6 alkyl, halogenated C3-C6 cycloalkyl, halogenated C1-C6 alkoxy, halogenated C3-C6 cycloalkyloxy, halogenated C1-C6 alkylamino, halogenated C3-C6 cycloalkylamino, C6-C8 aryl or C5-C8 heteroaryl, and at least one atom of the substituents represented by R2 or the substituent as a whole is substituted by a radionuclide.

[0009] In the compound of the general formula (I), R 1 is preferably hydrogen, C1-C6 alkyl or C3-C6 cycloalkyl.

[0010] In the compound of the general formula (I), R 2 is one or more substituents on the benzene ring or the 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 alkylamino, halogenated C1-C4 alkyl, halogenated C1-C4 alkoxy or halogenated C1-C4 alkylamino, and at least one atom or the entire group of these substituents is substituted with a radionuclide.

[0012] In the compound of the general formula (I), the radioactive nuclide 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)methanone, 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)methanone, 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)methanone, 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)methanone, 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)methanone, (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)methanone, 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)methanone.

[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)methanone, 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)methanone, KIDJI-007 Precursor (1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl)(4-tri-n-butyltinphenyl)methanone, KIDJI-008 Precursor (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)methanone, KIDJI-009 Precursor (4-nitro-2-(tri-n-butyltinyl)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl)methanone, KIDJI-010 Precursor (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)methanone.

[0015] The pharmaceutically acceptable salts of the compounds of the present invention are addition salts of inorganic or organic acids, 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 (i.e., 2-hydroxysuccinic acid), lactic acid and fumaric acid.

[0016] The solvates of the compounds of the present invention are preferably hydrates.

[0017] The present invention also provides the use of any of the above compounds or their pharmaceutically acceptable salts, precursors, and solvates in the preparation of diagnostic drugs 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 a 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, 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.

[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: Formulating any of the above compounds, or pharmaceutically acceptable salts, precursors, or solvates thereof, into a physiologically acceptable solution; introducing the solution into a subject; Imaging the subject's kidneys; Analyze the images and make a diagnosis based on the analysis results.

[0022] In the above diagnostic methods, imaging is preferably performed by PET or SPECT.

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

[0024] Technical Effects The present invention provides a radioactive diagnostic drug, its use in the diagnosis of diabetic nephropathy, and a method for diagnosing diabetic nephropathy. By intravenously injecting the radioactive diagnostic drug and performing PET or SPECT imaging, the purpose of non-invasive diagnosis of diabetic nephropathy can be achieved. Compared with the conventional invasive examination of kidney puncture, it has the advantages of less pain for the subject and fewer contraindications. Simple diagram description

[0025] FIG. 1 shows the ex vivo autoradiography images of 18F-KIDJI-003 in normal mice and diabetic nephropathy model mice. FIG. 2 shows the quantitative analysis results of 18F-KIDJI-003 in vitro autoradiography of normal mice and diabetic nephropathy model mice. FIG3 shows the in vivo SPECT imaging 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. FIG. 4 shows the 18F-KIDJI-003 in vitro autoradiography images of kidneys of normal mice, heterozygous diabetic nephropathy mice, and homozygous diabetic nephropathy mice. FIG. 5 shows the results of P2X7R immunostaining experiments in the kidneys of normal mice, heterozygous and homozygous diabetic nephropathy mice. Implementation

[0026] Features, characteristics, compounds, chemical moieties or groups described in conjunction with an embodiment or example of the present invention should be understood to be applicable to any other embodiment or example described herein, unless incompatible therewith. All features disclosed in this specification (including the scope of the invention patent application, the abstract and the drawings) and / or all steps of any method or process disclosed thereby can be combined in any way, except for at least some mutually exclusive combinations of these features and / or steps. The present invention is not limited to the details of any embodiment. The present invention extends to any new feature or any new combination of features disclosed in this specification (including the scope of the invention patent application, the abstract and the drawings), or to any new step or any new combination of steps of any method or process disclosed thereby.

[0027] Imaging Isotopes and Imaging: Diagnostic techniques in nuclear medicine use radioactive tracers that emit gamma rays from within the body. These tracers are usually short-lived isotopes attached to a compound that allow detailed examination of specific physiological processes. They can be given by injection, inhalation, or orally. The first type detects single photons by a gamma camera, which can view an organ from many different angles. The camera creates an image based on the points where the radiation was emitted; the image is enhanced by a computer and viewed by the doctor on a monitor for signs of abnormalities.

[0028] Positron emission tomography (PET) is a precise and complex technique that uses isotopes produced by cyclotrons. Positron-emitting radionuclides are usually introduced by injection and accumulate in target tissues. When the radionuclide decays, it emits a positron, which rapidly combines with a nearby electron, resulting in the simultaneous emission of two identifiable gamma rays in opposite directions. These are detected by the PET camera and indicate their source very accurately. The most important clinical role of PET is in oncology, using fluorine-18fluorodeoxyglucose ([ 18F]FDG) as a tracer, as it has been shown to be the most accurate non-invasive method for detecting and evaluating most cancers. It is also well used for cardiac and brain imaging.

[0029] Many medical diagnostic procedures, including PET and SPECT, utilize radiolabeled compounds, which are well known in the art. PET and SPECT are very 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 corresponding non-radiolabeled compounds. Tracers or probes can be radiolabeled with radionuclides useful for PET imaging, such as 11C, 13N, 15O, 18F, 64Cu, and 124I, or with radionuclides useful for SPECT imaging, such as 99Tc, 77Br, 61Cu, 153Gd, 123I, 125I, 131I, and 32P. These are non-limiting examples of the term "radionuclide" (also referred to as radioisotope, imaging isotope) as used herein.

[0030] Regarding radiohalogens, the isotope 123I has a half-life of 13 hours and a gamma energy of 159 keV, so ligands to be used for diagnostic purposes are usually labeled with this isotope or 18F (half-life of 2 hours). Other imaging isotopes that can be used include 131I, 77Br, and 76Br.

[0031] Those of ordinary skill in the art are familiar with various ways of detecting labeled compounds for imaging purposes. For example, radiolabeled compounds may be detected using positron emission tomography (PET) or single photon emission computed tomography (SPECT). The label introduced into the compound may depend on the desired detection method. Those of ordinary skill in the art are familiar with PET detection of positron emitting atoms such as 18F. Those of ordinary skill in the art are familiar with SPECT detection of photon emitting atoms such as 123I or 99Tc.

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

[0033] Typically, in the first step of the imaging method, a labeled compound is introduced into a tissue or subject in a detectable amount. The compound is typically part of a pharmaceutical composition and is administered to the tissue or subject by methods known to those of ordinary skill in the art. Typically, administration is by intravenous injection.

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

[0035] A detectable amount is the amount of labeled compound necessary to be detected by the selected detection method. The amount of labeled compound to be introduced into a subject to provide detectability can be readily determined by one of ordinary skill in the art to which the invention pertains. For example, increasing amounts of labeled compound may be administered to a subject until the compound is detected using the selected detection method. Radionuclides are introduced into a compound to provide detection of the compound.

[0036] The amount of time required can be readily determined by introducing a detectable amount of a labeled compound into a subject and then detecting the labeled compound at various times after administration.

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

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

[0039] definition In the examples of the present invention, unless otherwise specified, all instruments, raw material components, experimental animals, and chemical reagents are commercially available products that are well known to those with ordinary knowledge in the technical field to which the present invention belongs; in the examples of the present invention, unless otherwise specified, the technical means used are conventional means that are well known to those with ordinary knowledge in the technical field to which the present invention belongs. The progress of the reaction of the present invention can be monitored by conventional monitoring methods in the art (such as TLC, HPLC, LCMS or NMR), and the reaction endpoint is generally when the reaction substrate disappears.

[0040] Experimental methods in the examples of the specification that do not specify specific conditions are generally carried out according to conventional conditions in the art or according to conditions recommended by the manufacturer. In the present invention, unless otherwise specified, "above", "below", and "within" mean including the number. When "including" and "comprising" are used to describe an embodiment herein, other similar embodiments described as "consisting of" and / or "consisting essentially of" are also provided. When "consisting essentially of" are used to describe an embodiment herein, other similar embodiments described as "consisting of" are also provided. The term "and / or" used in phrases such as "A and / or B" herein is intended to include both A and B; A or B; A (alone); and B (alone). Similarly, the term "and / or" 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 the present invention, the term "C1-C6 alkyl" refers to a straight or branched alkyl group having 1 to 6 carbon atoms in the chain. For example, 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-dimethylbutanyl, 2,4-dimethylbutanyl, 3,3-dimethylbutanyl, 2-ethylbutanyl, etc., and groups that are considered to be equivalent to any of the above examples according to the ordinary skills in the art and the teachings provided herein. Similarly, the term "C1-C4 alkyl" refers to a straight or branched alkyl group having 1 to 4 carbon atoms in the chain.

[0042] The term "C3-C6 cycloalkyl" refers to a saturated monocyclic or polycyclic carbocyclic 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 would be considered equivalent to any of the foregoing examples based on the ordinary skills in the art and the teachings provided herein.

[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, which 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 is preferably a 1-alkenyl. Exemplary alkenyl groups include but are not limited to vinyl, propenyl, butenyl, pentenyl, hexenyl, and groups that are considered equivalent to any of the foregoing examples based on the common skills in the art and the teachings provided herein. The group may be a terminal group or a bridging group.

[0044] The term "C2-C6 alkynyl" refers to a group having 2 to 6 carbon atoms and containing at least one carbon-carbon triple bond, which may be straight or branched. The group may contain multiple triple bonds. The alkynyl group is preferably a 1-alkynyl group. Exemplary alkynyl groups include, but are not limited to, ethynyl, propynyl, butynyl, pentynyl, hexynyl, and groups that would be considered equivalent to any of the foregoing examples based on the ordinary skill in the art and the teachings provided herein. 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 includes methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentyl (e.g., 2-methylbutoxy, 2-methoxybutyl), neopentyl (e.g., 2,2-dimethylpropoxy), cyclopentyloxy, n-hexyloxy, 2-methylpentyloxy, 2-methoxypentyl, 3-methylpentyloxy, 3-methoxypentyl, 2,3-dimethylbutoxy, 2,4-dimethylbutoxy, 3,3-dimethylbutoxy, 2,3-dimethoxybutyl, 2,4-dimethoxybutyl, 3,3-dimethoxybutanyl, 2-ethylbutoxy, 2-ethoxybutanyl, and the like, as well as groups that would be considered equivalent to any of the foregoing examples based on the ordinary skills in the art and the teachings provided herein.

[0046] The term "C1-C6 alkylamino" refers to an NH2-alkyl(C1-C6) group, wherein alkyl(C1-C6) is as defined herein for 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 rest 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 a halogen is optionally substituted for hydrogen. C1-C6 alkyl is as defined above. Examples include, but are not limited to, trifluoromethyl (CF 3), difluoromethyl (CF 2H), monofluoromethyl (CH 2F), pentafluoroethyl (CF 2CF 3), tetrafluoroethyl (CHFCF 3), monofluoroethyl (CH 2CH 2F), trifluoroethyl (CH 2CF 3), tetrafluorotrifluoromethylethyl (-CF(CF 3) 2), and groups that are considered equivalent to any of the foregoing examples according to the ordinary skill in the art and the teachings provided herein.

[0049] The term "C1-C6 haloalkoxy" refers to a C1-C6 alkoxy group optionally replacing hydrogen with halogen. C1-C6 alkoxy is as defined 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 are considered equivalent to any of the foregoing examples according to the ordinary skill in the art and the teachings provided herein.

[0050] The term "C1-C6 haloalkylamino" refers to a C1-C6 alkylamino group in which hydrogen is optionally substituted with halogen. C1-C6 alkylamino group is as defined above.

[0051] The term "C6-C8 aryl group" refers to an aromatic carbocyclic ring having a ring structure in which all ring atoms are carbon atoms, preferably each ring has 6 to 8 carbon atoms, and examples of aryl groups include phenyl, etc. The group may 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) having 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, isoindolizine, pyrrole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, tetrazole, indole, isoindole, 1H-indazole, purine, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, cinnoline, oxazole, phenanthridine, acridine, phenazine, isothiazole, phenothiazine, oxazole, isoxazole, furazan, phenoxazine, 2-, 3-, or 4-pyridyl, 2-, 3-, 4-, 5-, or 8-quinolyl, 1-, 3-, 4-, or 5-isoquinolyl, 1-, 2-, or 3-indolyl, and 2- or 3-thienyl. The group may be a terminal group or a bridging group.

[0053] The term "substituted" means that the specified group or moiety bears one or more substituents. The term "optionally substituted" means that the specified group is unsubstituted or substituted with one or more substituents. If the term "substituted" is used to describe a structural system, it means that substitution occurs at any valency allowed position on the system. In the case where a specified moiety or group is not explicitly stated to be optionally substituted or substituted with any specified substituent, it is understood that such moiety or group is intended to be unsubstituted. The terms "one or more", "one or more" in reference to substituents refer to one substituent to the highest number of substitutions that is chemically possible, i.e., replacing one atom with its corresponding radioisotope, until all atoms are replaced.

[0054] The term "diagnosis" refers to the act of identifying a disease from its signs and symptoms, and in the present invention, specifically refers to the analysis of biomarkers indicative of a disease.

[0055] The term "subject" includes humans and non-human animals. Non-human animals include all vertebrates, e.g., mammals and non-mammals, such as non-human primates, sheep, dogs, cows, chickens, amphibians and reptiles. Except where noted, the terms "patient" or "subject" are used interchangeably herein.

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

[0057] The term "pharmaceutically acceptable" refers to products or compounds that are approved by the Chinese drug regulatory authorities or listed in the Chinese Pharmacopoeia or other generally recognized pharmacopoeias for use in animals including humans.

[0058] The "precursor" of the present invention is a chemical substance in the previous stage of the production of the compound of general formula (I). The chemical substance can produce a radiolabeled compound of formula (I) through a radiolabeling chemical reaction.

[0059] The compounds of general formula (I) can form addition salts with suitable non-toxic 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 the compounds of general formula (I) according to conventional 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 corresponding asymmetrically substituted starting materials. If necessary, the protection of any active group can be carried out in any suitable step. The protecting group is suitably a protecting group conventionally used in the conventional art, and they can be introduced and removed by conventional methods. For example, when the amine group is protected by 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 is described in detail below with reference to the examples.

[0062] Example 1: Preparation method of the precursor compound of the present invention The precursor compound of the present invention is prepared according to the following flow chart:

[0063] Embodiment 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)methanone (precursor of KIDJI-003)

[0064] Step 1. Synthesis of Compound 2 2-Chloropyrimidine (10.0 g, 1.0 eq) was placed in a 100 mL three-necked flask, protected by N 2, and the temperature was controlled at T≤30°C. Hydrazine hydrate (20 mL, 4.7 eq) was slowly added dropwise, and stirred at room temperature for 16 hours. The reaction of the raw material was complete (pure ethyl acetate, the product polarity became larger) monitored by TLC. The mixture was concentrated to dryness under reduced pressure, and n-hexane (50 mL) was added to slurry for 2 hours, filtered, and the filter cake was washed with n-hexane (20 mL). The solid was concentrated to dryness and pumped dry with an oil pump to obtain 7.7 g of a white solid with a yield of 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. A 50% aqueous acetic acid solution (100 mL) was added. The temperature was lowered to below 0°C. A solution of sodium nitrite (6.3 g, 2.0 eq) in water (25 mL) was slowly added dropwise. The temperature was controlled at T≤5°C. The addition was completed in half an hour. The mixture was reacted at 0°C for about 2 hours. After the reaction of the raw materials was completed by TLC monitoring, solid sodium carbonate 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 without concentration.

[0066] Step 3. Synthesis of compound 4 Compound 3 (0.7 g, 1.0 eq) and (S)-2-methyl-4-oxopiperidin-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, N 2 was protected, the temperature was raised to 70°C, tetrahydropyrrole (0.316 g, 0.77 mmol) was injected with a syringe, the temperature was raised to 100°C, the reaction was continued for 16 h, and new spots were generated by TLC monitoring. 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, and anhydrous dichloromethane (10 mL) was added under N2 protection. Sodium bicarbonate (0.11 g, 1.0 eq) was added, and m-CPBA (0.33 g, 1.0 eq) was slowly added. The mixture was stirred at room temperature for 2 hours, and the reaction of the raw materials was monitored by TLC. After the reaction was completed, 1N sodium hydroxide aqueous solution (10 mL) was added, stirred for 20 minutes, extracted with dichloromethane, and the organic phase was collected, dried, concentrated under reduced pressure, and directly used in the next step.

[0068] Step 5. Synthesis of Compound 6 Compound 5 (1 g, 1.0 eq) was placed in a 100 mL single-necked bottle, protected by N2, and TFA (2.4 g, 10 eq) was added. The mixture was stirred at room temperature for 16 h. The reaction of the raw material was completed by TLC monitoring. The mixture was concentrated under reduced pressure to remove TFA, and dichloromethane was added. A 10% aqueous sodium carbonate solution was added to adjust the pH to about 8. The mixture was extracted with dichloromethane three times. The organic phase was collected, dried, filtered, concentrated under reduced pressure, and purified by column chromatography (DCM / MeOH=15:1).

[0069] Step 6. 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)methanone (Compound 7; KIDJI-003 precursor) Compound 6 (60 g, 1.0 eq) was placed in a 100 mL three-necked flask, protected by N 2, and 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, and stirred at room temperature for 16 h. LCMS monitoring showed that the product was generated. Saturated brine (20 ml) was added for washing, and dichloromethane was extracted. The organic phase was collected, concentrated under reduced pressure, and purified by column chromatography; then spin-dried 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] Example 1-2: Preparation of KIDJI-004 Precursor According to the method of Example 1-1, chloronicotinic acid was replaced by 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)methanone (KIDJI-004 precursor).

[0071] Embodiment 1-3: According to the method of Example 1-1, (S)-2-methyl-4-oxopiperidin-1-carboxylic acid tert-butyl ester was replaced by N-tert-butyloxycarbonyl-4-piperidinone; chloronicotinic acid was replaced by 3-n-butyltinbenzoic 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)methanone (KIDJI-007 precursor).

[0072] Embodiment 1-4: According to the method of Example 1-1, (S)-2-methyl-4-oxopiperidin-1-carboxylic acid tert-butyl ester was replaced by N-tert-butyloxycarbonyl-4-piperidinone; chloronicotinic acid was replaced by 3-n-butyltin-4-methoxybenzoic acid to prepare (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)methanone (KIDJI-008 precursor).

[0073] Embodiment 1-5: According to the method of Example 1-1, (S)-2-methyl-4-oxopiperidin-1-carboxylic acid tert-butyl ester was replaced by N-tert-butyloxycarbonyl-4-piperidinone; chloronicotinic acid was replaced by 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)methanone (KIDJI-009 precursor).

[0074] Embodiment 1-6: According to a method similar to Example 1-1, (S)-2-methyl-4-oxopiperidine-1-carboxylic acid tert-butyl ester was replaced by N-tert-butyloxycarbonyl-4-piperidinone; chloronicotinic acid was replaced by 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)methanone (KIDJI-010 precursor).

[0075] Example 2: Labeling synthesis

[0076] Labeling Synthesis Example 2-1 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)methanone (18F-KIDJI-003)

[0077] According to the following route, 18F-labeled (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-5yl)methanone (compound 7, KIDJI-003 precursor) was used as the labeling precursor to prepare 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-5yl)methanone (18F-KIDJI-003).

[0078] Weigh 5 mg of amino polyether (kryptofix) 222 and K 2CO 3 (3 mg) respectively and place them in a 1.5 mL EP tube, add pure water (100 µL) and acetonitrile (400 µL) to prepare kryptofix-222 / K 2CO 3 solution, take the kryptofix-222 / K 2CO 3 solution through a QMA column to elute 18F- into a 3 mL conical bottom fluorination reaction tube, heat at 135°C and blow nitrogen to dry for 3-5 minutes. Take anhydrous acetonitrile (300 µL) and add it to the fluorination reaction tube, heat at 135°C to dry, and bubble nitrogen for 2 minutes, repeat three times to fully remove water and dry.

[0079] Compound 7 (2 mg) was dissolved in anhydrous DMSO (200 µL), and 4 µL KF (potassium fluoride) solution (1.5 mg / mL DMSO) was added. The mixture was added to the reaction tube and stirred at 135°C for 10 minutes. After the reaction was completed, the entire reaction solution was separated and purified by HPLC. HPLC used a reverse C18 column (Waters Atlantis T3 10×250 mm, 5 um); the mobile phase was CH 3CN / H 2O (0.1% TFA) = 36 : 64; the flow rate was 2.0 mL / min. The fractions with a retention time of 37-38 minutes were collected, and the fractions of the obtained labeled compound were transferred to a 20 mL rotary evaporator and concentrated under reduced pressure to dryness in the rotary evaporator. 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%. Molar activity 61-87 GBq / µmol. 1H NMR (500 MHz, Chloroform-d) δ8.95-8.91 (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: Synthesis of 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)methanone (18F-KIDJI-004) According to the method of similar labeling synthesis example 2-1, (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)methanone was used to label the precursor to obtain the product. The radiochemical purity was >95%. The molar activity was 58-90 GBq / µmol.

[0081] Labeling Synthesis Example 2-3: Synthesis of 131I-labeled (4-iodophenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl)methanone (131I-KIDJI-007) 131I-KIDJI007 was prepared 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)methanone as the labeled precursor.

[0082] 65 μL phosphate buffer (0.3M, pH=5.5) was placed in a 1.5 mL low adsorption reaction tube, 20 μL labeled precursor (1 mg / mL methanol) was added, 5 uL 131I-NaI (200 μCi, Xinke Pharmaceuticals), 5 μL chloramine T (0.4 mg / mL H 2O) was added, vortexed at room temperature for 3 minutes, and 100 μL Na 2S 2O 5 (2.0 mg / mL H 2O) was added to quench the reaction. The product was purified by high performance liquid chromatography (chromatographic column, CAPCELLPAK C18 UG120 (φ6.0mm×150mm; Shiseido, Tokyo, Japan); mobile phase, CH 3CN / H 2O, 10 / 90~100 / 0, v / v; flow rate, 1.0 mL / min), and the radioactive product was collected at the corresponding time point. Repeat the above process until enough radioactive drugs (1.2-3 mCi) are collected. Concentrate to dryness under reduced pressure, add physiological saline (containing 2.5% (V / V) Tween 80 and 2.5% (V / V) ascorbic acid solution) to prepare radiolabeled product injection. The radiochemical purity is not less than 95%.

[0083] Labeling Synthesis Example 2-4: Synthesis of 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)methanone (131I-KIDJI-008) According to the method of labeled synthesis example 2-3, (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)methanone was used as the labeled precursor to prepare the product with a radiochemical purity of >95%.

[0084] Labeling Synthesis Example 2-5: Synthesis of 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)methanone (131I-KIDJI-009) According to the method of labeling synthesis example 2-3, (4-nitro-2-(tri-n-butyltinyl)phenyl)(1-(pyrimidin-2-yl)-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl)methanone was used as the labeling precursor to prepare the product. The radiochemical purity was >95%.

[0085] Labeling Synthesis Example 2-6: The labeled synthesis of 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)methanone (131I-KIDJI-010) was prepared according to the method of labeled synthesis example 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)methanone as the labeled precursor, with a radiochemical purity of >95%.

[0086] Example 3: Ex vivo autoradiography of 18F-KIDJI-003 The spontaneous type 2 diabetes mouse model uses the db / db homozygous mice (BKS.Cg-Dock7m+ / +LeprdbJ; JAX® Mice Strain Code 607) discovered by the Jackson Laboratory in the United States. The Leptin receptor gene on chromosome 4 is defective, causing db / db mice to become bulimic and obese from the age of four weeks, and to show obvious hyperglycemia, hyperlipidemia, insulin resistance and other characteristics as they age. The course of the disease is very similar to that of type 2 diabetes subjects. The control group mice use normal mice (m / m) or heterozygous mice (m / db).

[0087] Mice were anesthetized with 1.5% (v / v) isoflurane and injected with 18F-KIDJI-003 (15 MBq) via the tail vein. After 60 minutes, mice were killed by dislocation, and kidneys were removed and quickly frozen in dry ice. 20 µm frozen sections were prepared using a cryostat (RWD Minux FS800). The frozen sections were placed on a development 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 is an ex vivo autoradiography. Compared with normal mice, 18F-KIDJI-003 showed obvious accumulation in the renal pelvis of diabetic nephropathy mice. The results of quantitative analysis (Figure 2) showed that the radioactivity of 18F-KIDJI-003 in the renal pelvis of diabetic nephropathy mice was more than 4 times that of the renal pelvis of normal mice. The data were from the left and right kidneys of 2 normal mice and 2 diabetic nephropathy mice, with a total of 4 kidneys in each group.

[0089] Example 4: In vivo imaging In vivo imaging example 4-1: PET in vivo imaging of 18F-KIDJI-004

[0090] PET scanning was 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 fixed in the center of the FOV of the PET scanner. Immediately after intravenous injection of 18F-KIDJI-004 (15 MBq), the radioactivity signal was acquired in 3D mode for 90 min. The energy window was 350-750 keV. After the completion of the PET scan, 5 μl / g body weight of ioversol injection (35%) (Optiray 350; Guerbet) was intravenously injected into the mice, and then a 30-second CT scan was immediately performed (X-ray source: 70 kV / 88 mA, FOV: 60 mm). During the PET and CT scans, the mice were anesthetized with 1.5% (v / v) isoflurane.

[0091] In vivo imaging example 4-2: SPECT in vivo imaging of 131I-KIDJI-007 SPECT scanning was 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 through the tail vein, and then the radiation signal was immediately acquired every 30 minutes for 2 hours in three-dimensional mode. The energy window was set to 360-700 keV. After the completion of the SPECT scan, 5 μl / g body weight of ioversol injection (Optiray 350; Guerbet) was injected through the tail vein of the mouse, and then a 30-second CT scan was immediately performed (X-ray source: 50 kV / 980 μA, 480 projections; During the SPECT and CT scans, the mice were anesthetized with 1.5% (v / v) isoflurane.

[0092] In vivo imaging Example 4-3: In vivo imaging of 131I-KIDJI-008 In vivo imaging of 131I-KIDJI-008 was performed in a similar manner to that of in vivo imaging Example 4-2, except that 131I-KIDJI-007 was replaced with 131I-KIDJI-008.

[0093] In vivo imaging Example 4-4: In vivo imaging of 131I-KIDJI-009 In vivo imaging of 131I-KIDJI-009 was performed in a similar manner to that of in vivo imaging Example 4-2, except that 131I-KIDJI-007 was replaced with 131I-KIDJI-009.

[0094] In vivo imaging example 4-5: In vivo imaging of 131I-KIDJI-010 In vivo imaging of 131I-KIDJI-010 was performed in a similar manner to that of in vivo imaging Example 4-2, except that 131I-KIDJI-007 was replaced with 131I-KIDJI-010.

[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 are all significantly accumulated in the renal pelvis of the kidneys of db / db model mice, but not in the kidneys of normal mice.

[0096] Example 5: In vitro autoradiography of mouse kidney tissue sections Fresh frozen kidneys of 6-month-old normal mice (m / m), diabetic nephropathy mice heterozygous (m / db) and homozygous (db / db) were frozen sections with a thickness of 20 µm. 18F-KIDJI-003 obtained in the labeled synthesis example 2-1 was added to 50 mM Tris-HCL buffer (pH 7.4) to prepare an incubation solution (final chemical concentration 5 nM). The kidney sections were immersed in the incubation solution containing or not containing non-radioactive labeled KIDJI-003 (10 µM), and after standing for 1 hour, they were washed with 50 mM Tris-HCL buffer (pH 7.4) for 2 minutes × 2 times. They were sealed in a developing plate for 1 hour, and the images were read and quantitatively analyzed using a radioautographic scanner (CR-35 Bio; Elysia-Raytest).

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

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

[0099] Example 6: Immunostaining experiment of mouse kidney tissue sections Normal mice (m / m), heterozygous (m / db) and homozygous (db / db) mice at 6 months of age were killed by cervical dislocation. The left and right kidneys were removed and immersed in 4% PFA / PBS fixative overnight to complete tissue fixation. After PBS washing, they were immersed in 20% sucrose / PBS solution overnight and 30% sucrose / PBS solution overnight to complete cryoprotection. Then, the kidneys were made into 10µm thick frozen sections using a cryostat (Rayward). P2X7R staining was performed using anti-P2X7R (Cat #: APR-004, Alomone labs) antibody. After the kidney sections were treated with an autoclave (citric acid buffer (0.01M sodium citrate: 0.01M citric acid = 5:1), 121°C, 5 minutes), they were washed with running water for 5 minutes, TSA blocking buffer (TSA Fluorescein System, NEL70000, Perkin Elmer) was added to the kidney sections, and the sections were left standing for 1 hour. The incubation solution containing the primary antibody (anti-P2X7R antibody, 1:1000) was added and left standing overnight. The primary antibody was discarded, and the washing was repeated 3 times with PBS for 5 minutes. The incubation solution containing the biotin-labeled secondary antibody was added and left standing for another 1 hour. Afterwards, the fluorescent signal was amplified using the TSA sensitization kit (TSA Fluorescein System, NEL70000; Perkin Elmer), and the sections were blocked using VECTASHILD mounting medium (H-1000, Vector Laboratories Inc.), and then observed under a microscope. 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), diabetic nephropathy mice heterozygous db / m (middle) and homozygous db / db (right). This result is consistent with the experimental results in Figure 4, which once again shows that P2X7R expression is not increased in diabetic nephropathy model db / db homozygous mice. Therefore, it is once again proved that the accumulation of 18F-KIDJI003 in the renal pelvis of diabetic nephropathy mice is not due to the binding of 18F-KIDJI003 and P2X7R.

[0100] Example 7: Diagnostic Method for Diabetic Nephropathy In the diagnosis of DKD in the subjects, as in the animal experiments, PET or SPECT imaging is performed after intravenous injection of 18F-KIDJI003 radioactive molecular probe, and diabetic nephropathy is diagnosed 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 some preferred embodiments of the present invention, it should be understood by those with ordinary knowledge in the technical field to which the present invention belongs that the above contents are further detailed descriptions of the present invention in combination with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Without departing from the spirit and scope of the present invention, those with ordinary knowledge in the technical field to which the present invention belongs can make various changes in form and details, including making some simple deductions or substitutions, which also belong to part of the present invention.

[0102] none

[0103] none

Claims

1. A compound of general formula (I) or a pharmaceutically acceptable salt, precursor, or solvate thereof: (I) wherein, X is 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, haloethyl, halo-n-propyl, halo-isopropyl, halo-n-butyl, halo-isobutyl, halo-tert-butyl, or halo-C1-C4 alkoxy, and at least one atom of the above substituents represented by R2 is replaced by a radioactive isotope, or R2 is a radioactive isotope, wherein the halogen is selected from fluorine, bromine, or iodine; the precursor of the compound is selected from: 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)(4-tri-n-butyltinphenyl) methyl ketone, KIDJI-008 precursor (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, 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.

2. The compound as claimed in claim 1 or a pharmaceutically acceptable salt, precursor, or solvate thereof, wherein the radionuclide is selected from one or more of 18F, 11C, 131I, 123I, 124I, and 125I.

3. The compound as claimed in claim 1, or a pharmaceutically acceptable salt, precursor, or solvate thereof, wherein the compound is selected from: 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, 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.

4. The compound as claimed in claim 1 or a pharmaceutically acceptable salt, precursor, or solvate thereof, wherein the pharmaceutically acceptable salt is an addition salt of an inorganic acid or an organic acid.

5. The compound as claimed in claim 4 or a pharmaceutically acceptable salt, precursor, or solvate thereof, 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.

6. The compound as described in claim 1 or a pharmaceutically acceptable salt, precursor, or solvate thereof, wherein the solvate is a hydrate.

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