A method for preparing a radioactive probe precursor

Abstract

The present invention discloses a method for preparing a radioactive probe precursor, which belongs to a chemical synthesis method. This method uses 5-bromoisatin and sodium pyruvate, which are common and inexpensive products on the market, as raw materials. FAPI-46 can be successfully prepared through 20 reactions, including a Pfitzinger reaction, high-temperature decarboxylation, tert-butyl protection of carboxyl groups, a C-N coupling reaction, removal of tert-butyl protection, methyl protection of tert-butyl groups, removal of methyl protection, and a condensation reaction. The shortest route requires only 10 reaction steps. Compared with methods reported in the literature, this method has good reproducibility, mild reaction conditions, few by-products, and is easy to purify. It is more practical and economical, and has obvious advantages.

Description

Technical Field

[0001] The present invention relates to the pharmaceutical field, specifically to a method for preparing FAPI-46, a fibroblast activation protein (FAP) inhibitor. FAPI-46 can be used as a precursor for preparing radioactive probes. The resulting probes, after labeling with radionuclides, can be used for diagnosis and internal radiotherapy of diseases characterized by FAP overexpression, such as cancer, localized inflammation, and tissue and organ fibrosis. The FAPI-46 preparation method described herein is simple, economical, and suitable for industrial production. Background Art

[0002] Early detection of malignant tumors is crucial for improving patient prognosis and prolonging survival. Tumor growth and spread depend not only on cancer cells but also on the tumor stroma, which plays a crucial role in cancer initiation, progression, and metastasis. Cancer-associated fibroblasts (CAFs) are a major cellular component of the tumor stroma. FAP, a type II transmembrane glycoprotein belonging to the dipeptidyl peptidase IV-like family, is a specific marker expressed on the surface of CAFs and activated fibroblasts, playing a crucial role in extracellular matrix remodeling and fibrosis. Its expression is low in healthy tissues but is highly expressed in over 90% of malignant epithelial tumors. High FAP expression has been shown to be an independent marker of poor prognosis in various cancers. Furthermore, FAP is also involved in tissue inflammation, scarring, and fibrosis. Therefore, FAP-targeted molecular imaging (positron emission tomography (PET) and single-photon emission computed tomography (SPECT)) is becoming a powerful diagnostic and therapeutic tool for cancer, fibrosis, inflammation, and other diseases.

[0003] In 2019, Anastasia Loktev et al. reported a series of FAP-targeted radioactive probes with better tumor retention developed based on FAPI-04, among which the compound FAPI-46 showed a higher tumor-to-background ratio and significantly prolonged tumor site accumulation. The structure of FAPI-46 shown in formula (I) and its preparation method have been disclosed in the literature (J Nucl Med., 2019, 60, 1421-1429.) and patent (WO 2019154886). This type of compound can be used to prepare FAP-targeted radioactive probes by labeling with radionuclides.

[0004]

[0005] The reported synthesis method of FAPI-46 is to use 6-bromoquinoline-4-carboxylic acid as the starting material, and finally obtain FAPI-46 through tert-butyl protection, CN coupling, mesylation of the hydroxyl group, nucleophilic substitution, removal of the tert-butyl protection, Boc group protection of piperazine, amide condensation, removal of the piperazine Boc protection, and aminolysis of DOTA-p-nitrophenol ester. The synthesis route is as follows:

[0006]

[0007] The starting material 6-bromoquinoline-4-carboxylic acid in the above-mentioned route is relatively expensive, making large-scale production costly. The palladium catalyst used in the second-step coupling reaction is relatively expensive, making large-scale production of Ic uneconomical. The sixth-step reaction, Boc-protection of the piperazine N, suffers from poor reproducibility, preventing stable and high-yield production of the intermediate Ig. Furthermore, the resulting product is an amphoteric compound, which cannot be effectively purified by normal-phase silica gel column chromatography and requires reverse-phase preparative HPLC, making large-scale production uneconomical. The seventh-step reaction, amide condensation using HBTU / HOBt, results in extremely low yields, with virtually no product obtained. Therefore, there is an urgent need to develop a novel, practical, economical, and reproducible method for synthesizing FAPI-46 to provide a reference and foundation for its large-scale production. Summary of the Invention

[0008] The problem to be solved by the present invention is to overcome a series of difficulties in synthesizing the compound of formula (I) reported in the literature, and aims to provide a new method for synthesizing FAPI-46 that is more novel, practical, economical and reproducible, providing a reference and laying a foundation for the large-scale preparation of FAPI-46.

[0009]

[0010] The synthetic route is as follows:

[0011]

[0012]

[0013] The specific steps include:

[0014] In some specific technical solutions, the method steps are as follows:

[0015] 1) the compound of formula (2) and sodium pyruvate are cyclized via a Pfitzinger reaction to construct a quinoline ring to obtain a compound of formula (3);

[0016] 2) the compound of formula (3) is subjected to high temperature decarboxylation to obtain the compound of formula (4);

[0017] 3) Compound (7) was prepared using compound (4) as a raw material. The technical scheme is as follows:

[0018] The compound of formula (4) is protected by tert-butyl to obtain compound (8); the compound of formula (8) is coupled with CN to obtain compound (9); the compound of formula (9) is subjected to mesylation of the hydroxyl group to obtain compound (10); the compound of formula (10) is de-tert-butylated to obtain compound (11); the compound of formula (11) is protected by methyl to obtain compound (7);

[0019] Or: the compound of formula (4) is protected by methyl for carboxyl group to obtain the compound of formula (5); the compound of formula (5) is coupled to the compound of formula (6) via CN; the compound of formula (6) is subjected to mesylation of the hydroxyl group to obtain the compound of formula (7);

[0020] 4) reacting the compound of formula (7) with N-Boc piperazine to obtain a compound of formula (12) through nucleophilic substitution;

[0021] 5) demethylating the compound of formula (12) to obtain the compound of formula (13);

[0022] 6) The compound of formula (13) is used as a raw material to prepare the compound of formula (14). The technical scheme is as follows:

[0023] The compound of formula (13) is condensed to obtain the compound of formula (14);

[0024] Or: the compound of formula (13) is subjected to a condensation reaction to obtain the compound of formula (15); the compound of formula (15) is subjected to a hydrolysis reaction to obtain the compound of formula (16); the compound of formula (16) is subjected to an amide condensation reaction to obtain the compound of formula (14);

[0025] Or: the compound of formula (13) is subjected to ester condensation to obtain the compound of formula (17); the compound of formula (17) is subjected to ester aminolysis to obtain the compound of formula (14).

[0026] 7) removing the Boc protection from the compound of formula (14) to obtain the compound of formula (18);

[0027] 8) The compound of formula (18) is subjected to ester aminolysis to obtain the compound of formula (I).

[0028] In the technical solution of the present invention, in step 1), the reaction is carried out under alkaline conditions, and the selected base is sodium carbonate, potassium carbonate, potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, cesium hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, preferably sodium hydroxide;

[0029] The solvent used is dimethyl sulfoxide, N,N-dimethylformamide, acetone, methanol, ethanol, water, preferably water;

[0030] The reaction temperature is 15-110°C, preferably 110°C; the reaction time is 4-12h, preferably 4h.

[0031] In the technical solution of the present invention, in step 2), the solvent used is an inert high-boiling-point liquid dispersant, preferably: the inert high-boiling-point liquid dispersant is at least one of ethylene glycol, propylene glycol, paraffin, diphenyl ether, cyclobutanol, benzyl alcohol and diformate, preferably diphenyl ether; the reaction temperature is 150-250°C, preferably 200°C; and the reaction time is 2-8h, preferably 4-5h.

[0032] In the technical solution of the present invention, in step 3), the reaction conditions are as follows:

[0033] The compound of formula (4) is protected by a tert-butyl group to obtain compound (8): the tert-butyl donor used is di-tert-butyl dicarbonate, tert-butyl 2,2,2-trichloroacetimidate, or O-tert-butyl-N,N'-diisopropylisourea, preferably di-tert-butyl dicarbonate; the catalyst is 4-dimethylaminopyridine, and the solvent can be tetrahydrofuran, 1,4-dioxane, dichloromethane, toluene, or acetone, preferably tetrahydrofuran. The reaction temperature is 15°C-55°C, preferably room temperature; and the reaction time is 8-24 hours, preferably 12 hours.

[0034] The compound of formula (8) is subjected to CN coupling to obtain the compound of formula (9): the selected solvent is dimethyl sulfoxide, N,N-dimethylformamide, water or toluene, preferably dimethyl sulfoxide; the selected copper ion catalyst is cuprous iodide, cupric chloride, copper sulfate or copper oxide, preferably cuprous iodide; the selected ligand is 2-methyl-N-methylimidazole, 2-pyridylcyclohexaneethyl ketone, 2-pyrrolecarbonamide, pyridine oxide or L-proline, preferably L-proline; the selected base is potassium carbonate, sodium carbonate, cesium carbonate, potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, potassium hydroxide, sodium hydroxide or potassium tert-butoxide, preferably potassium carbonate; the reaction is protected by inert gas; the reaction temperature is 70°C-150°C, preferably 100°C; the reaction time is 4-12 hours, preferably 10 hours.

[0035] In the compound of formula (9) obtained by mesylation of the hydroxyl group to obtain the compound of formula (10), the selected mesylate donor is methanesulfonyl chloride or methanesulfonic anhydride, preferably methanesulfonyl chloride; the selected base is triethylamine or N,N-diisopropylethylamine, preferably triethylamine; the selected solvent is dichloromethane, tetrahydrofuran, dimethyl sulfoxide or N,N-dimethylformamide, preferably dichloromethane; the reaction temperature is 0-40°C; and the reaction time is 1-8h, preferably 1-3h.

[0036] In the process of removing the tert-butyl group of the compound of formula (10) to obtain the compound of formula (11), the acid used is trifluoroacetic acid, acetic acid, formic acid, trifluoromethanesulfonic acid, hydrochloric acid, hydrobromic acid, sulfuric acid or nitric acid, preferably trifluoroacetic acid; the solvent can be chloroform, 1,2-dichloroethane, 1,4-dioxane, ethyl acetate or dichloromethane, preferably dichloromethane; the reaction temperature is 0-45° C., and the reaction time is 1-4 h.

[0037] The compound of formula (11) is protected by methyl to obtain the compound of formula (7), wherein the methyl donor used is methyl iodide, methyl bromide, methyl chloride, dimethyl sulfate, preferably methyl iodide; the base used is potassium carbonate, sodium carbonate, cesium carbonate, potassium hydroxide or sodium hydroxide, preferably potassium carbonate; the solvent can be N,N-dimethylformamide, dimethyl sulfoxide, acetone, methanol, ethanol or water, preferably N,N-dimethylformamide; the reaction temperature is 0-100°C; the reaction time is 2-8h, preferably 1-3h;

[0038] The compound of formula (4) is subjected to methyl protection of the carboxyl group to obtain the compound of formula (5): the methyl donor used is methyl iodide, methyl bromide, methyl chloride or dimethyl sulfate, preferably methyl iodide; the base selected is potassium carbonate, sodium carbonate, cesium carbonate, potassium hydroxide or sodium hydroxide, preferably potassium carbonate; the solvent is N,N-dimethylformamide, dimethyl sulfoxide, acetone, methanol, ethanol or water, preferably N,N-dimethylformamide; the reaction temperature is 0-100°C, preferably room temperature; the reaction time is 1-4h;

[0039] The compound of formula (5) is coupled to the compound of formula (6) via CN: the solvent selected is dimethyl sulfoxide, N,N-dimethylformamide, water or toluene, preferably dimethyl sulfoxide; the copper ion catalyst selected is cuprous iodide, cupric chloride, copper sulfate or copper oxide, preferably cuprous iodide; the ligand selected is 2-methyl-N-methylimidazole, 2-pyridylcyclohexaneethyl ketone, 2-pyrrolecarbonamide, pyridine oxide or L-proline, preferably L-proline; the base selected is potassium carbonate, sodium carbonate, cesium carbonate, potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, potassium hydroxide, sodium hydroxide or potassium tert-butoxide, preferably potassium carbonate; the reaction is protected by inert gas; the reaction temperature is 70°C-150°C, preferably 100°C; the reaction time is 4-12h;

[0040] The compound of formula (6) is subjected to mesylation to obtain the compound of formula (7): the selected mesylate donor is methanesulfonyl chloride or methanesulfonic anhydride, preferably methanesulfonyl chloride; the selected base is triethylamine or N,N-diisopropylethylamine, preferably triethylamine; the selected solvent is dichloromethane, tetrahydrofuran, dimethyl sulfoxide or N,N-dimethylformamide, preferably dichloromethane; the reaction temperature is 0-40°C, and the reaction time is 1-3h.

[0041] In the technical solution of the present invention, in step 4), the reaction is carried out under alkaline conditions, and the base used is potassium carbonate, sodium carbonate, cesium carbonate, potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, potassium hydroxide or sodium hydroxide, preferably potassium carbonate; the catalyst used is potassium iodide or sodium iodide, preferably sodium iodide; the solvent is N,N-dimethylformamide, dimethyl sulfoxide, acetone, methanol, ethanol or water, preferably N,N-dimethylformamide; the reaction temperature is 50-100° C., preferably 70° C.; and the reaction time is 2-10 h, preferably 2.5 h.

[0042] In the technical solution of the present invention, in step 5), the reaction is carried out under alkaline conditions, and the base used is sodium hydroxide, potassium hydroxide or lithium hydroxide, preferably lithium hydroxide; the solvent is tetrahydrofuran, dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, water or methanol, preferably methanol and water; the reaction temperature is 0-55°C, preferably room temperature; and the reaction time is 12-24h, preferably 24h.

[0043] In the technical solution of the present invention, in step 6), the compound of formula (13) is condensed to obtain the compound of formula (14), and the reaction is carried out under alkaline conditions. The base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene, preferably N-methylimidazole; the condensing agent used is 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate Phosphate, N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate, O-[(ethoxycarbonyl)cyanomethylamine]-N,N,N',N'-tetramethylthiourea hexafluorophosphate, tetramethylfluorouronium hexafluorophosphate or 2-bromo-1-ethylpyridinium tetrafluoroborate, preferably N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate; the selected solvent is N,N-dimethylformamide or acetonitrile, preferably acetonitrile; the reaction temperature is 0-50°C, preferably room temperature; the reaction time is 6-24h, preferably 12h.

[0044] The compound of formula (13) is subjected to a condensation reaction to obtain a compound of formula (15): the reaction is carried out under alkaline conditions, the base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene, preferably N,N-diisopropylethylamine; the condensing agent used is 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate, N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate, O-[(ethoxycarbonyl)cyanomethylamine]-N,N,N',N'-tetramethylthiourea hexafluorophosphate, tetramethylfluorouronium hexafluorophosphate, 1-hydroxybenzotriazole or 2-bromo-1-ethylpyridinium tetrafluoroborate, preferably benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate (HBTU) and 1-hydroxybenzotriazole (HOBt); the selected solvent is N,N-dimethylformamide or acetonitrile, preferably N,N-dimethylformamide; the reaction temperature is 0-50°C, preferably room temperature; the reaction time is 6-24h, preferably 6h.

[0045] The compound of formula (15) is subjected to hydrolysis to obtain the compound of formula (16); the base used is sodium hydroxide, potassium hydroxide or lithium hydroxide, preferably lithium hydroxide; the solvent is tetrahydrofuran, dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, water or methanol, preferably methanol and water; the reaction temperature is 0-55°C, preferably room temperature, and the reaction time is 6-24 hours, preferably 24 hours.

[0046] The compound of formula (16) is subjected to an amide condensation reaction to obtain a compound of formula (14); the reaction is carried out under alkaline conditions, and the base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene, preferably N-methylimidazole; the condensing agent used is 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-N,N,N',N'-tetramethyluronium Hexafluorophosphate, N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate, O-[(ethoxycarbonyl)cyanomethylamino]-N,N,N',N'-tetramethylthiourea hexafluorophosphate, tetramethylfluorouronium hexafluorophosphate, or 2-bromo-1-ethylpyridinium tetrafluoroborate, preferably N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate; the solvent is N,N-dimethylformamide or acetonitrile, preferably acetonitrile; the reaction temperature is 0-50°C, preferably room temperature; the reaction time is 6-24 hours, preferably 12 hours.

[0047] The compound of formula (13) is subjected to ester condensation to obtain the compound of formula (17); the selected succinimide donor is N-hydroxysuccinimide, N-chlorosuccinimide, N-bromosuccinimide or N-iodosuccinimide, preferably N-hydroxysuccinimide; the selected dehydrating agent is N,N'-diisopropylcarbodiimide or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI), preferably 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI); the solvent is tetrahydrofuran, dichloromethane, N,N-dimethylformamide or dimethyl sulfoxide, preferably N,N-dimethylformamide; the reaction temperature is -10-25°C, preferably 0°C; the reaction time is 1-4h, preferably 2h.

[0048] The compound of formula (17) is subjected to ester aminolysis to obtain the compound of formula (14): the base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene, preferably N,N-diisopropylethylamine; the solvent selected is dimethyl sulfoxide, N,N-dimethylformamide, dichloromethane or toluene, preferably dichloromethane; the reaction temperature is 0-55°C, preferably room temperature; the reaction time is 2-8h, preferably 4h.

[0049] In the technical solution of the present invention, in step 7), the acid used is trifluoroacetic acid, acetic acid, formic acid, trifluoromethanesulfonic acid, hydrochloric acid, hydrobromic acid, sulfuric acid or nitric acid, preferably hydrochloric acid; the solvent selected is ethyl acetate, 1,4-dioxane, dichloromethane or tetrahydrofuran, preferably ethyl acetate; the temperature is 0-45°C, preferably room temperature; the reaction time is 0.5-2h, preferably 1h.

[0050] In the technical solution of the present invention, the reaction is carried out under alkaline conditions, and the base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene, preferably N,N-diisopropylethylamine; the solvent is dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, tetrahydrofuran or dichloromethane, preferably N,N-dimethylformamide; the reaction temperature is 0-45°C, preferably room temperature; and the reaction time is 1-12 hours, preferably 8 hours.

[0051] The key steps of this invention include a two-step reaction from the compound of formula (2) to obtain the compound of formula (4), a CN coupling reaction, a four-step reaction from the compound of formula (10) to obtain the compound of formula (13), a five-step reaction from the compound of formula (4) to obtain the compound of formula (13), and a condensation reaction from the compound of formula (13) to obtain the compound of formula (14). They are described below:

[0052] The compound of formula (2) undergoes Pfitzinger reaction to construct quinoline dicarboxylic acid and undergoes high-temperature decarboxylation to obtain the compound of formula (4). The reaction raw materials are cheap and readily available, the reaction operation is simple, and it is convenient for mass production.

[0053] The compound of formula (8) is subjected to copper-mediated CN coupling to obtain the product of formula (9), which has the advantages of simple operation, cheap raw materials, few by-products and high yield.

[0054] The compound of formula (10) undergoes tert-butyl removal, methyl protection, N-Boc piperazine substitution, and demethylation to obtain the compound of formula (13). This route circumvents the low yield, poor reproducibility, and difficulty in mass production and purification of the product encountered in the two-step reaction reported in prior patents, which involves simultaneous removal of Boc protection and tBu protection followed by single Boc protection. This synthetic route is simple to operate, has high yields, is easy to purify, and is conducive to mass production.

[0055] Compound (4) undergoes methyl protection of the carboxyl group, CN coupling, mesylation of the hydroxyl group, N-Boc piperazine substitution, and demethylation to obtain compound (13). This route circumvents the low yield, poor reproducibility, and difficulty in mass production and purification of the product encountered in the two-step reaction reported in prior patents, which involves simultaneous removal of Boc protection and tBu protection followed by single Boc protection. This synthetic route is short, simple to operate, and easy to purify, making it suitable for mass production.

[0056] The compound of formula (13) is condensed with compound (19) using TCFH as a condensing agent and NMI as a base to obtain the compound of formula (14). Unlike the previous patent, which used HBTU / HATU and HOBt for condensation, which resulted in extremely low yields or even no product, this method is simple to handle, has high and stable yields, and does not require stringent reaction conditions, making it suitable for mass production.

[0057] In summary, the novel method for preparing FAPI-46 (compound of formula (I)) provided by the present invention has the following advantages:

[0058] 1. The raw materials 5-bromoisatin and sodium pyruvate are easily available and inexpensive, thus reducing production costs.

[0059] 2. Compared with the methods in existing literature and patents, the method has better reproducibility, higher and more stable yield, simple operation, mild reaction conditions, easy control, and easy purification of reaction products.

[0060] 3. Most of the reagents used in the reaction are general reagents. The purification of other intermediates except the final product is free from the constraints of preparative liquid phase, which is more suitable for industrial production.

[0061] 4. New synthetic pathways and methods have greater practical application significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 is the H NMR spectrum of the compound of formula (3);

[0063] Figure 2 is the H NMR spectrum of the compound of formula (4);

[0064] Figure 3 is the H NMR spectrum of the compound of formula (8);

[0065] Figure 4 is the H NMR spectrum of the compound of formula (9);

[0066] Figure 5 is the H NMR spectrum of the compound of formula (10);

[0067] Figure 6 is the H NMR spectrum of the compound of formula (11);

[0068] Figure 7 is the H NMR spectrum of the compound of formula (7);

[0069] Figure 8 is the H NMR spectrum of the compound of formula (12);

[0070] Figure 9 is the H NMR spectrum of the compound of formula (14);

[0071] Figure 10 is the H NMR spectrum of the compound of formula (15);

[0072] Figure 11 is the H NMR spectrum of the compound of formula (5);

[0073] Figure 12 is the H NMR spectrum of the compound of formula (6);

[0074] Figure 13 is the hydrogen nuclear magnetic resonance spectrum of the compound of formula (17). DETAILED DESCRIPTION

[0075] The following examples are provided to illustrate the present invention in detail. The following examples are provided to better illustrate the present invention and are not intended to limit the scope of the present invention.

[0076] Example 1

[0077] 6-Bromoquinoline-2,4-dicarboxylic acid

[0078]

[0079] 5-Bromoisatin (5.0 g, 22.1 mmol) was added to a 2.5 M aqueous NaOH solution (53.2 mL, 133 mmol), followed by sodium pyruvate (2.92 g, 26.5 mmol). The reaction was refluxed at 110°C for 4 h. After the reaction was complete, the system was cooled to room temperature and the pH was adjusted to 2 with hydrochloric acid. A large amount of solid precipitated. The solid precipitate was filtered, washed with water, and dried thoroughly in a desiccator to yield 6.12 g of a brown solid with a purity of 97% and a yield of 93%. 1 H NMR (400MHz, DMSO) δ9.09 (d, J = 1.98Hz, 1H), 8.53 (s, 1H), 8.19 (d, J = 9.01Hz, 1H), 8.07 (dd, J1 = 2.04Hz, J2 = 9.03Hz, 1H).

[0080] Example 2

[0081] 6-Bromoquinoline-4-carboxylic acid

[0082]

[0083] 6-Bromoquinoline-2,4-dicarboxylic acid (6.12 g, 20.7 mmol) was added to 50 mL of diphenyl ether and stirred at 200°C for 5 h. After the reaction was complete, the system was cooled to room temperature and 30 mL of acetone was added. The solid was filtered, washed with acetone and diethyl ether, and dried to obtain 4.94 g of a gray solid with a purity of 98% and a yield of 95%. 1 H NMR (400MHz, DMSO) δ9.09(d,J=4.38Hz,1H),9.01(d,J=2.13Hz,1H),8.07(d,J=8.95Hz,1H),8.03(d,J=4.41Hz,1H),7.98(dd,J1=2.14Hz,J2=8.96Hz 1H).

[0084] Example 3

[0085] tert-Butyl 6-bromoquinoline-4-carboxylate

[0086]

[0087] Di-tert-butyl dicarbonate (4.9 g, 19.5 mmol) was added to a solution of 6-bromoquinoline-4-carboxylic acid (10.9 g, 50 mmol) in tetrahydrofuran (45 mL). The mixture was stirred at room temperature for 30 minutes, followed by the addition of 4-dimethylaminopyridine (244 mg, 2 mmol). The mixture was stirred at room temperature for 12 hours. After TLC analysis, the reaction mixture was diluted with 150 mL of ethyl acetate and washed with saturated sodium bicarbonate solution, followed by washing once with water and once with saturated brine. The organic phase was collected, dried over anhydrous sodium sulfate, and the solvent evaporated under reduced pressure. Flash column chromatography yielded 4.94 g of a white solid with a purity of 97% and a yield of 82%. 1 H NMR (400MHz, CDCl3) δ9.02(d,J=2.08Hz,1H),9.00(d,J=4.42Hz,1H),8.02(d,J=8.9 3Hz, 1H), 7.87 (d, J = 4.39Hz, 1H), 7.83 (d, J1 = 2.22Hz, J2 = 8.91Hz, 1H), 1.68 (s, 9H).

[0088] Example 4

[0089] tert-Butyl 6-(3-hydroxypropylmethylamino)quinoline-4-carboxylate

[0090]

[0091] tert-Butyl 6-bromoquinoline-4-carboxylate (3.0 g, 9.8 mmol), L-proline (1.13 g, 9.8 mmol), cuprous iodide (931 mg, 4.9 mmol), and potassium carbonate (5.39 g, 39.1 mmol) were placed in a two-necked flask and evacuated to argon. 30 mL of dimethyl sulfoxide was added to the flask, followed by 3-(methylamino)-1-propanol (2.61 g, 29.3 mmol) dissolved in 5 mL of dimethyl sulfoxide. Stir at 100°C for 10 h. After completion of the reaction, monitored by TLC, the reaction solution was poured into 70 mL of water. The aqueous phase was extracted with ethyl acetate (30 mL x 3). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent evaporated under reduced pressure. Flash column chromatography afforded 1.3 g of a yellow oil with a purity of 98% and a yield of 42%. 1H NMR (400MHz, CDCl3) δ8.64(d,J=4.49Hz,1H),7.97(d,J=9.32Hz,1H),7.84(d,J=2.89Hz,1H),7.74(d,J=4.54Hz,1 H),7.43(dd,J1=2.85Hz,J2=9.41Hz,1H),3.76(t,2H),3.65(t,2H),3.11(s,3H),1.95-1.89(m,2H),1.67(s,9H).

[0092] Example 5

[0093] tert-Butyl 6-(methyl(3-((methylsulfonyl)oxy)propyl)amino)quinoline-4-carboxylate

[0094]

[0095] Triethylamine (3.43 mL, 24.7 mmol) was added to a 20 mL solution of tert-butyl 6-(3-hydroxypropylmethylamino)quinoline-4-carboxylate (1.3 g, 4.1 mmol) in dichloromethane and stirred at 0°C for 10 min. Methanesulfonyl chloride (0.64 mL, 8.2 mmol) was slowly added dropwise while maintaining 0°C. After addition, the mixture was stirred at 0°C for 30 min, allowed to warm to room temperature, and then allowed to react at room temperature for another 1 h. After completion of the reaction, as monitored by TLC, saturated ammonium chloride solution was added to the mixture at 0°C and stirred for 10 min to quench the reaction. After quenching, the mixture was separated and the organic phase was collected. The organic phase was washed twice with water and once with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Flash column chromatography yielded 1.46 g of a yellow oil with a purity of 98% and a yield of 90%. 1 H NMR (400MHz, CDCl3) δ8.66(d,J=4.52Hz,1H),7.98(d,J=9.34Hz,1H),7.85(d,J=2.68Hz,1H),7.76(d,J=4.58Hz,1H),7. 36(dd,J1=2.87Hz,J2=9.38Hz,1H),4.31(t,2H),3.65(t,2H),3.12(s,3H),3.00(s,3H),2.14-2.08(m,2H),1.66(s,9H).

[0096] Example 6

[0097] 6-(Methyl(3-((methylsulfonyl)oxy)propyl)amino)quinoline-4-carboxylic acid

[0098]

[0099] Trifluoroacetic acid (16.5 mL, 111 mmol), triisopropylsilane (0.76 mL, 3.7 mmol), and trifluoromethanesulfonic acid (0.81 mL, 9.3 mmol) were slowly added to a solution of tert-butyl 6-(methyl(3-((methylsulfonyl)oxy)propyl)amino)quinoline-4-carboxylate (1.46 g, 3.7 mmol) in dichloromethane (20 mL) at 0°C. The mixture was stirred at room temperature for 1 h. After completion of the reaction, as monitored by TLC, the solvent was evaporated under reduced pressure. The residue was washed with diethyl ether and the remaining solvent was evaporated again under reduced pressure. 2.0 g of a crude red oil was obtained, which was used directly in the next step without further purification. 1 H NMR (400MHz, DMSO) δ8.89(d,J=5.43Hz,1H),8.20(d,J=5.44Hz,1H),8.08(d,J=9.50Hz,1H),7.86(dd,J1=2.67Hz ,J2=9.56Hz,1H),7.76(d,J=2.47Hz,1H),4.28(t,2H),3.68(t,2H),3.20(s,3H),3.16(s,3H),2.04-1.97(m,2H).

[0100] Example 7

[0101] Methyl 6-(methyl(3-((methylsulfonyl)oxy)propyl)amino)quinoline-4-carboxylate

[0102]

[0103] The crude product from the previous step was dissolved in N,N-dimethylformamide (25 mL), and potassium carbonate (2.04 g, 14.8 mmol) and iodomethane (1.58 g, 11.1 mmol) were added to the system, and stirred at room temperature for 2 h. After completion of the reaction, as monitored by TLC, the reaction solution was diluted with 50 mL of water, and the aqueous phase was extracted with ethyl acetate (25 mL x 3). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Flash column chromatography afforded 900 mg of an orange-red oil with a purity of 97% and a two-step yield of 69%. 1 H NMR (400MHz, CDCl3) δ8.68(d,J=4.53Hz,1H),8.01(d,J=9.34Hz,1H),7.97(d,J=2.78Hz,1H),7.86(d,J=4.55Hz,1H),7. 39(dd,J1=2.81Hz,J2=9.38Hz,1H),4.33(t,2H),4.00(s,3H),3.67(t,3H),3.14(s,3H),3.03(s,3H),2.17-2.10(m,2H).

[0104] Example 8

[0105] Methyl 6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carboxylate

[0106]

[0107] Potassium carbonate (3.92 g, 28.4 mmol), sodium iodide (2.98 g, 19.9 mmol), and 1-Boc piperazine (2.91 g, 15.6 mmol) were added sequentially to a solution of methyl 6-(methyl(3-((methylsulfonyl)oxy)propyl)amino)quinoline-4-carboxylate (5.0 g, 14.2 mmol) in anhydrous N,N-dimethylformamide (30 mL). The mixture was stirred at 70°C for 2.5 h. After completion of the reaction, as monitored by TLC, 70 mL of water was added for dilution, and the aqueous phase was extracted with ethyl acetate (30 mL x 3). The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Flash column chromatography afforded 5.2 g of an orange-yellow oil with a purity of 98% and a yield of 83%. 1 H NMR (400MHz, CDCl3) δ8.62(d,J=4.49Hz,1H),7.93(d,J=9.31Hz,1H),7.89(d,J=2.74Hz,1H),7.81(d,J=4.56Hz,1H),7.41(dd,J1 =2.82Hz, J2=9.42Hz,1H),3.97(s,3H),3.54(t,2H),3.43(t,4H),3.07(s,3H),2.40-2.36(m,4H),1.85-1.78(m,2H),1.43(s,9H).

[0108] Example 9

[0109] Lithium 6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carboxylate

[0110]

[0111] 1M lithium hydroxide (13 mL, 12.9 mmol) was added to a solution of methyl 6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carboxylate (5.2 g, 11.7 mmol) in methanol (40 mL) and water (8 mL) and stirred at room temperature for 24 h. After completion of the reaction as monitored by TLC, methanol was evaporated under reduced pressure, the residue was dissolved in water (20 mL), and the aqueous phase was washed with ethyl acetate (30 mL x 3). The aqueous phase was lyophilized to obtain 5.7 g of a yellow solid with a yield of 99%. The lyophilized product was used directly in the next reaction.

[0112] Example 10

[0113] tert-Butyl (S)-4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate

[0114]

[0115] (S)-4,4-Difluoro-1-glycylpyrrolidine-2-carbonitrile (570 mg, 2.5 mmol), N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate (TCFH) (710 mg, 2.5 mmol), N-methylimidazole (NMI) (0.42 mL, 7.1 mmol), and lithium 6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carboxylate (1.0 g, 2.3 mmol) were dissolved in anhydrous acetonitrile (25 mL) and stirred at room temperature for 12 h. After completion of the reaction, the reaction solution was diluted with water (50 mL), and the aqueous phase was extracted with ethyl acetate (25 mL x 5). The ethyl acetate was combined. The remaining substrate in the aqueous phase was then extracted with dichloromethane (25 mL x 3). The dichloromethane was combined, and the solvent was evaporated under reduced pressure. The reaction was then repeated. The combined ethyl acetate was washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The product was purified by flash column chromatography to give 658 mg of a yellow solid with a purity of 97% and a yield of 48%. 1 H NMR (400MHz, CDCl3) δ8.52(d,J=4.36Hz,1H),7.89(d,J=9.29Hz,1H),7.38(dd,J1=2.40Hz,J2= 9.41Hz,1H),7.32(d,J=4.24Hz,1H),7.23(t,2H),4.95-4.92(m,1H),4.32(dd,J1=5.42Hz,J2= 17.46Hz,1H),4.15(dd,J1=4.55Hz,J2=17.46Hz,1H),4.07-3.91(m,2H),3.54-3.47(m,2H),3. 42(t,4H),3.02(s,3H),2.85-2.72(m,2H),2.40-2.37(m,6H),1.82-1.75(m,2H),1.43(s,9H).

[0116] Example 11

[0117] 6-Bromoquinoline-4-carboxylic acid methyl ester

[0118]

[0119] 6-Bromoquinoline-2,4-dicarboxylic acid (500 mg, 2 mmol) was dissolved in N,N-dimethylformamide (10 mL). Potassium carbonate (1.1 g, 8 mmol) and iodomethane (852 mg, 6 mmol) were added to the mixture and stirred at room temperature for 2 h. After completion of the reaction, as monitored by TLC, 20 mL of water was added to dilute the reaction solution. The aqueous phase was then extracted with ethyl acetate (10 mL x 3). The combined organic phases were washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Flash column chromatography afforded 387 mg of a pale yellow solid with a purity of 97% and a yield of 73%. 1H NMR (400MHz, CDCl3) δ9.02 (t, 2H), 8.02 (d, J = 8.99Hz, 1H), 7.94 (d, J = 4.49Hz, 1H), 7.84 (dd, J1 = 2.12Hz, J2 = 8.99Hz, 1H), 4.04 (s, 3H).

[0120] Example 12

[0121] 6-(3-Hydroxypropylmethylamino)quinoline-4-carboxylic acid methyl ester

[0122]

[0123] Methyl 6-bromoquinoline-4-carboxylate (265 mg, 1 mmol), L-proline (115 mg, 1 mmol), cuprous iodide (95 mg, 0.5 mmol), and potassium carbonate (552 mg, 4 mmol) were placed in a two-necked flask and evacuated to argon. 6 mL of dimethyl sulfoxide was added to the flask, followed by 3-(methylamino)-1-propanol (267 mg, 3 mmol) dissolved in 2 mL of dimethyl sulfoxide. Stir at 100°C for 10 h. After completion of the reaction, monitored by TLC, the reaction solution was poured into 16 mL of water. The aqueous phase was extracted with ethyl acetate (8 mL x 3). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent evaporated under reduced pressure. Flash column chromatography afforded 20 mg of a yellow oil with a purity of 97% and a yield of 7%. 1 H NMR (400MHz, CDCl3) δ8.65 (d, J = 9.41Hz, 1H), 7.98 (d, J = 9.28Hz, 1H), 7.94 (d, J = 2.89Hz, 1H), 7.83 (d, J = 4. 46Hz,1H),7.43(dd,J1=2.84Hz,J2=9.44Hz,1H),4.00(s,3H),3.77(t,2H),3.65(t,2H),1.96-1.90(m,2H).

[0124] Example 13

[0125] Methyl 6-(methyl(3-((methylsulfonyl)oxy)propyl)amino)quinoline-4-carboxylate

[0126]

[0127] Triethylamine (304 mL, 2.2 mmol) was added to a solution of methyl 6-(3-hydroxypropylmethylamino)quinoline-4-carboxylate (100 mg, 0.37 mmol) in dichloromethane (5 mL) and stirred at 0°C for 10 min. Methanesulfonyl chloride (84 mg, 0.73 mmol) was slowly added dropwise while maintaining 0°C. After addition, the mixture was stirred at 0°C for 30 min, allowed to warm to room temperature, and allowed to react at room temperature for 1 h. After completion of the reaction, as monitored by TLC, saturated ammonium chloride solution was added to the mixture at 0°C and stirred for 10 min to quench the reaction. After quenching, the mixture was separated and the organic phase was collected. The organic phase was washed twice with water and once with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Flash column chromatography yielded 120 mg of an orange-red oil with a purity of 99% and a yield of 94%.

[0128] Example 14

[0129] tert-Butyl 4-(3-((4-((2-methoxy-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate

[0130]

[0131] N,N-Diisopropylethylamine (0.16 mL, 0.92 mmol) was added to a solution of lithium 6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carboxylate (100 mg, 0.23 mmol) in anhydrous N,N-dimethylformamide (6 mL). Glycine methyl ester hydrochloride (29 mg, 0.23 mmol), benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate (HBTU) (87 mg, 0.23 mmol), and 1-hydroxybenzotriazole (HOBt) (31 mg, 0.23 mmol) were then added. The mixture was stirred at room temperature for 6 h. After completion of the reaction, the reaction solution was diluted with water (12 mL), the aqueous phase was extracted with ethyl acetate (6 mL x 3), and the organic phases were combined. The combined organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Flash column chromatography gave 60 mg of an orange-yellow oil with a purity of 97% and a yield of 52%. 1H NMR (400MHz, CDCl3) δ8.52(d,J=4.36Hz,1H),7.87(d,J=9.40Hz,1H),7.39(dd,J1=2.80Hz,J2=9.49Hz,1H),7.30(d,J=4.39Hz,1H),7.22(d,J=2.73Hz 1H),6.90(t,1H),4.29(d,J=5.53Hz,2H),3.79(S,3H),3.51(t,2H),3.42 (t,4H),3.03(s,3H),2.41-2.37(m,6H),1.83-1.76(m,2H),1.43(s,9H).

[0132] Example 15

[0133] Lithium (6-((3-(4-(tert-Butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carbonyl)glycinate

[0134]

[0135] 1M lithium hydroxide (0.13 mL, 0.13 mmol) was added to a solution of tert-butyl 4-(3-((4-((2-methoxy-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate (60 mg, 0.12 mmol) in methanol (5 mL) and water (1 mL), and the mixture was stirred at room temperature for 24 h. After completion of the reaction as monitored by TLC, methanol was evaporated under reduced pressure, the residue was dissolved in water (10 mL), and the aqueous phase was washed with ethyl acetate (3 mL x 3). The aqueous phase was lyophilized and used directly in the next reaction.

[0136] Example 16

[0137] tert-Butyl (S)-4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate

[0138]

[0139] (S)-4,4-Difluoropyrrolidine-2-carbonitrile (12 mg, 0.12 mmol), N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate (TCFH) (37 mg, 0.13 mmol), N-methylimidazole (NMI) (29 μL, 0.37 mmol), and lithium (6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carbonyl)glycinate (0.12 mmol) were dissolved in anhydrous acetonitrile (6 mL) and stirred at room temperature for 12 h. After completion of the reaction, the reaction solution was diluted with water (12 mL), and the aqueous phase was extracted with ethyl acetate (6 mL x 5). The ethyl acetate was combined. The remaining substrate in the aqueous phase was then extracted with dichloromethane (6 mL x 3). The dichloromethane was combined, and the solvent was evaporated under reduced pressure. The reaction was then repeated. The combined ethyl acetate was washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Flash column chromatography gave 32 mg of an orange-yellow oil with a purity of 97% and a yield of 45%.

[0140] Example 17

[0141] 2,5-Dioxopyrrolidin-1-yl 6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carboxylate

[0142]

[0143] 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) (34 mg, 0.18 mmol) and N-hydroxysuccinimide (HOSu) (21 mg, 0.18 mmol) were added to a solution of lithium 6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carboxylate (70 mg, 0.16 mmol) in N,N-dimethylformamide (3 mL) at 0°C. The mixture was stirred at 0°C for 2 h. After completion of the reaction, as monitored by TLC, the reaction solution was diluted with water (6 mL), the aqueous phase was extracted with ethyl acetate (3 mL x 3), and the organic phase was collected. The organic phase was washed twice with water and once with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Flash column chromatography afforded 56 mg of an orange-red oil with a purity of 97% and a yield of 66%. 1H NMR (400MHz, CDCl3) δ8.67(d,J=4.61Hz,1H),8.01(d,J=4.61Hz,1H),7.97(d,J=9.39Hz,1H),7.69(d,J=2.88Hz,1H),7.46(dd,J1=2. 85Hz, J2=9.66Hz,1H),3.56(t,3H),3.43(t,4H),3.09(s,3H),3.02-2.87(m,4H),2.39-2.33(m,6H),1.85-1.78(m,2H),1.45(s,9H).

[0144] Example 18

[0145] tert-Butyl (S)-4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate

[0146]

[0147] N,N-Diisopropylethylamine (0.15 mL, 0.86 mmol) was added to a solution of (S)-4,4-difluoro-1-glycylpyrrolidine-2-carbonitrile (26 mg, 0.12 mmol) in anhydrous dichloromethane (3 mL). After stirring at room temperature for 10 minutes, 2,5-dioxopyrrolidin-1-yl 6-((3-(4-(tert-butoxycarbonyl)piperazin-1-yl)propyl)(methyl)amino)quinoline-4-carboxylate (56 mg, 0.12 mmol) was added to the solution. Stir at room temperature for 4 hours. After completion of the reaction, the solvent was evaporated directly, and flash column chromatography was performed to obtain 19 mg of a yellow solid with a purity of 98% and a yield of 30%.

[0148] Example 19

[0149] (S)-N-(2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)-6-(methyl(3-(piperazin-1-yl)propyl)amino)quinoline-4-carboxamide

[0150]

[0151] A 2 M solution of hydrogen chloride in ethyl acetate (2 mL) was added to a solution of tert-butyl (S)-4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate (20 mg, 0.033 mmol) in ethyl acetate (2 mL) and stirred at room temperature for 1 h. After completion of the reaction, the solvent was evaporated to dryness and used directly in the next reaction without purification.

[0152] Example 20

[0153] (S)-2,2',2"-((10-(2-(4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazin-1-yl)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid

[0154]

[0155] DIPEA (58 μL, 0.33 mmol) was added to a solution of (S)-N-(2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)-6-(methyl(3-(piperazin-1-yl)propyl)amino)quinoline-4-carboxamide (0.033 mmol) in anhydrous N,N-dimethylformamide (3 mL). After stirring at room temperature for 20 min, 1-(2,5-dioxo-1-pyrrolidinyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA-NHS Ester) (17 mg, 0.033 mmol) was added, and stirring was continued at room temperature for 8 h. The product was then isolated by HPLC and lyophilized to yield 22 mg of the title compound with a purity of 99% and a yield of 74%. ESI-MS: [(M+2) / 2] + 443.66.

Claims

1. A method for preparing a radioactive probe precursor, characterized in that:

2. The method according to claim 1, wherein The steps of this method are as follows: 1) the compound of formula (2) and sodium pyruvate are cyclized via a Pfitzinger reaction to construct a quinoline ring to obtain a compound of formula (3); 2) the compound of formula (3) is subjected to high temperature decarboxylation to obtain the compound of formula (4); 3) Compound (7) was prepared using compound (4) as a raw material. The technical scheme is as follows: The compound of formula (4) is protected by tert-butyl to obtain compound (8); the compound of formula (8) is coupled with CN to obtain compound (9); the compound of formula (9) is subjected to mesylation of the hydroxyl group to obtain compound (10); the compound of formula (10) is de-tert-butylated to obtain compound (11); the compound of formula (11) is protected by methyl to obtain compound (7); Or: the compound of formula (4) is protected by methyl for carboxyl group to obtain the compound of formula (5); the compound of formula (5) is coupled to the compound of formula (6) via CN; the compound of formula (6) is subjected to mesylation of the hydroxyl group to obtain the compound of formula (7); 4) reacting the compound of formula (7) with N-Boc piperazine to obtain a compound of formula (12) through nucleophilic substitution; 5) demethylating the compound of formula (12) to obtain the compound of formula (13); 6) The compound of formula (13) is used as a raw material to prepare the compound of formula (14). The technical scheme is as follows: The compound of formula (13) is condensed to obtain the compound of formula (14); Or: the compound of formula (13) is subjected to a condensation reaction to obtain the compound of formula (15); the compound of formula (15) is subjected to a hydrolysis reaction to obtain the compound of formula (16); the compound of formula (16) is subjected to an amide condensation reaction to obtain the compound of formula (14); Or: the compound of formula (13) is subjected to ester condensation to obtain the compound of formula (17); the compound of formula (17) is subjected to ester aminolysis to obtain the compound of formula (14); 7) removing the Boc protection from the compound of formula (14) to obtain the compound of formula (18); 8) The compound of formula (18) is subjected to ester aminolysis to obtain the compound of formula (I).

3. The method according to claim 2, wherein In step 1), the reaction is carried out under alkaline conditions, and the selected base is sodium carbonate, potassium carbonate, potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, cesium hydroxide, sodium hydroxide, potassium hydroxide, and lithium hydroxide; The solvents used were dimethyl sulfoxide, N,N-dimethylformamide, acetone, methanol, ethanol, and water; The reaction temperature is 15-110°C and the reaction time is 4-12h.

4. The method according to claim 3, wherein In step 1), the base selected is sodium hydroxide; the solvent used is water; the reaction temperature is 110° C., and the reaction time is 4 h.

5. The method according to claim 2, wherein In step 2), the solvent used is an inert high-boiling-point liquid dispersant, the reaction temperature is 150-250° C., and the reaction time is 2-8 hours.

6. The method according to claim 5, wherein In step 2), the inert high-boiling-point liquid dispersant is at least one of ethylene glycol, propylene glycol, paraffin, diphenyl ether, cyclobutanol, benzyl alcohol and diformate, the reaction temperature is 200° C., and the reaction time is 4-5 hours.

7. The method according to claim 6, wherein In step 2), the inert high-boiling-point liquid dispersant is diphenyl ether.

8. The method according to claim 1, wherein In step 3), the reaction conditions are as follows: The compound of formula (4) is protected by tert-butyl group to obtain compound (8): the tert-butyl donor used is di-tert-butyl dicarbonate, tert-butyl 2,2,2-trichloroacetimidate or O-tert-butyl-N,N'-diisopropylisourea; the catalyst is 4-dimethylaminopyridine, and the selected solvent is tetrahydrofuran, 1,4-dioxane, dichloromethane, toluene or acetone; the reaction temperature is 15°C-55°C, and the reaction time is 8-24h; The compound of formula (8) is subjected to CN coupling to obtain the compound of formula (9): the solvent selected is dimethyl sulfoxide, N,N-dimethylformamide, water or toluene; the copper ion catalyst selected is cuprous iodide, cupric chloride, copper sulfate or copper oxide; the ligand selected is 2-methyl-N-methylimidazole, 2-pyridylcyclohexaneethyl ketone, 2-pyrrolecarbonamide, pyridine oxide or L-proline; the base selected is potassium carbonate, sodium carbonate, cesium carbonate, potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, potassium hydroxide, sodium hydroxide or potassium tert-butoxide; the reaction is protected by inert gas; the reaction temperature is 70° C.-150° C.; the reaction time is 4-12 h; The compound of formula (9) is subjected to mesylation of the hydroxyl group to obtain the compound of formula (10), wherein the selected mesylate donor is methanesulfonyl chloride or methanesulfonic anhydride; the selected base is triethylamine or N,N-diisopropylethylamine; the selected solvent is dichloromethane, tetrahydrofuran, dimethyl sulfoxide or N,N-dimethylformamide; the reaction temperature is 0-40°C; the reaction time is 1-8h; In the process of removing the tert-butyl group of the compound of formula (10) to obtain the compound of formula (11), the acid used is trifluoroacetic acid, acetic acid, formic acid, trifluoromethanesulfonic acid, hydrochloric acid, hydrobromic acid, sulfuric acid or nitric acid; the solvent is chloroform, 1,2-dichloroethane, 1,4-dioxane, ethyl acetate or dichloromethane; the reaction temperature is 0-45°C, and the reaction time is 1-4h; The compound of formula (11) is protected by methyl to obtain the compound of formula (7), wherein the methyl donor used is methyl iodide, methyl bromide, methyl chloride, or dimethyl sulfate; the base used is potassium carbonate, sodium carbonate, cesium carbonate, potassium hydroxide, or sodium hydroxide; the solvent can be N,N-dimethylformamide, dimethyl sulfoxide, acetone, methanol, ethanol, or water; the reaction temperature is 0-100°C; and the reaction time is 2-8h; The compound of formula (4) is protected by methyl for carboxyl group to obtain the compound of formula (5): the methyl donor used is iodomethane, bromomethane, chloromethane or dimethyl sulfate; the base used is potassium carbonate, sodium carbonate, cesium carbonate, potassium hydroxide or sodium hydroxide; the solvent is N,N-dimethylformamide, dimethyl sulfoxide, acetone, methanol, ethanol or water; the reaction temperature is 0-100°C, and the reaction time is 1-4h; The compound of formula (5) is coupled to the compound of formula (6) via CN: the solvent selected is dimethyl sulfoxide, N,N-dimethylformamide, water or toluene; the copper ion catalyst selected is cuprous iodide, cupric chloride, copper sulfate or copper oxide; the ligand selected is 2-methyl-N-methylimidazole, 2-pyridylcyclohexaneethyl ketone, 2-pyrrolecarbonamide, pyridine oxide or L-proline; the base selected is potassium carbonate, sodium carbonate, cesium carbonate, potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, potassium hydroxide, sodium hydroxide or potassium tert-butoxide; the reaction is protected by inert gas; the reaction temperature is 70°C-150°C, and the reaction time is 4-12 hours; The compound of formula (6) is subjected to mesylation to obtain the compound of formula (7): the selected mesylate donor is methanesulfonyl chloride or methanesulfonic anhydride; the selected base is triethylamine or N,N-diisopropylethylamine; the selected solvent is dichloromethane, tetrahydrofuran, dimethyl sulfoxide or N,N-dimethylformamide; the reaction temperature is 0-40°C, and the reaction time is 1-3h.

9. The method according to claim 8, wherein In step 3), the reaction conditions are as follows: The compound of formula (4) is protected by tert-butyl group to obtain compound (8): the tert-butyl donor used is di-tert-butyl dicarbonate; the selected solvent is tetrahydrofuran; the reaction temperature is room temperature; the reaction time is 12h; The compound of formula (8) is subjected to CN coupling to obtain the compound of formula (9): the selected solvent is dimethyl sulfoxide; the selected copper ion catalyst is cuprous iodide; the selected ligand is L-proline; the selected base is potassium carbonate; the reaction temperature is 100° C.; the reaction time is 10 h; The compound of formula (9) is subjected to mesylation of the hydroxyl group to obtain the compound of formula (10), wherein the selected mesylate donor is mesylate chloride; the selected base is triethylamine; the selected solvent is dichloromethane; and the reaction time is 1-3 hours; In the process of removing the tert-butyl group of the compound of formula (10) to obtain the compound of formula (11), the acid used is trifluoroacetic acid; the solvent is dichloromethane; The compound of formula (11) is protected by methyl to obtain the compound of formula (7), wherein the methyl donor used is iodomethane; the base used is potassium carbonate; the solvent is N,N-dimethylformamide; the reaction time is 1-3h; The compound of formula (4) is subjected to methyl protection of the carboxyl group to obtain the compound of formula (5): the methyl donor used is iodomethane; The base used is potassium carbonate; the solvent is N,N-dimethylformamide; the reaction temperature is room temperature; The compound of formula (5) is coupled to the compound of formula (6) via CN: the selected solvent is dimethyl sulfoxide; the selected copper ion catalyst is cuprous iodide; The selected ligand is L-proline; the selected base is potassium carbonate; the reaction temperature is 100°C; The compound of formula (6) is subjected to mesylation to obtain the compound of formula (7): the selected mesylate donor is methanesulfonyl chloride; the selected base is triethylamine; and the selected solvent is dichloromethane.

10. The method according to claim 2, wherein In step 4), the reaction is carried out under alkaline conditions, and the base used is potassium carbonate, sodium carbonate, cesium carbonate, potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, potassium hydroxide or sodium hydroxide; the catalyst used is potassium iodide or sodium iodide; the solvent is N,N-dimethylformamide, dimethyl sulfoxide, acetone, methanol, ethanol or water; the reaction temperature is 50-100° C.; and the reaction time is 2-10 h.

11. The method according to claim 10, wherein In step 4), the reaction is carried out under alkaline conditions, the base used is potassium carbonate; the catalyst used is sodium iodide; the solvent is N,N-dimethylformamide; the reaction temperature is 70° C.; and the reaction time is 2.5 h.

12. The method according to claim 2, wherein In step 5), the reaction is carried out under alkaline conditions, the base used is sodium hydroxide, potassium hydroxide or lithium hydroxide; the solvent is tetrahydrofuran, dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, water or methanol; the reaction temperature is 0-55° C., and the reaction time is 12-24 h.

13. The method according to claim 12, wherein: In step 5), the reaction is carried out under alkaline conditions, the base used is lithium hydroxide; the solvent is methanol and water; the reaction temperature is room temperature; and the reaction time is 24 hours.

14. The method according to claim 2, wherein In step 6), the compound of formula (13) is condensed to obtain the compound of formula (14). The reaction is carried out under alkaline conditions. The base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene; the condensing agent used is 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-N,N,N ',N'-tetramethyluronium hexafluorophosphate, N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate, O-[(ethoxycarbonyl)cyanomethylamine]-N,N,N',N'-tetramethylthiourea hexafluorophosphate, tetramethylfluorouronium hexafluorophosphate or 2-bromo-1-ethylpyridinium tetrafluoroborate; the selected solvent is N,N-dimethylformamide or acetonitrile; the reaction temperature is 0-50°C; the reaction time is 6-24h; The compound of formula (13) is subjected to a condensation reaction to obtain the compound of formula (15): the reaction is carried out under alkaline conditions, the base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene; the condensation agent used is 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate, N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate, O-[(ethoxycarbonyl)cyanomethylamine]-N,N , N', N'-tetramethylthiourea hexafluorophosphate, tetramethylfluorouronium hexafluorophosphate, 1-hydroxybenzotriazole or 2-bromo-1-ethylpyridinium tetrafluoroborate; the selected solvent is N, N-dimethylformamide or acetonitrile; the reaction temperature is 0-50 ° C, and the reaction time is 6-24h; the compound of formula (15) is hydrolyzed to obtain the compound of formula (16); the base used is sodium hydroxide, potassium hydroxide or lithium hydroxide; the solvent is tetrahydrofuran, dichloromethane, N, N-dimethylformamide, dimethyl sulfoxide, water or methanol; the reaction temperature is 0-55 ° C, and the reaction time is 6-24h; The compound of formula (16) is subjected to an amide condensation reaction to obtain a compound of formula (14); the reaction is carried out under alkaline conditions, and the base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene; the condensing agent used is 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-N,N,N', N'-tetramethyluronium hexafluorophosphate, N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate, O-[(ethoxycarbonyl)cyanomethylamine]-N,N,N',N'-tetramethylthiourea hexafluorophosphate, tetramethylfluorouronium hexafluorophosphate or 2-bromo-1-ethylpyridinium tetrafluoroborate; the solvent is N,N-dimethylformamide or acetonitrile; the reaction temperature is 0-50°C, and the reaction time is 6-24h; The compound of formula (13) is subjected to ester condensation to obtain the compound of formula (17); the selected succinimide donor is N-hydroxysuccinimide, N-chlorosuccinimide, N-bromosuccinimide or N-iodosuccinimide; the selected dehydrating agent is N,N'-diisopropylcarbodiimide or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI); the solvent is tetrahydrofuran, dichloromethane, N,N-dimethylformamide or dimethyl sulfoxide; the reaction temperature is -10-25°C, and the reaction time is 1-4h; The compound of formula (17) is subjected to ester aminolysis to obtain the compound of formula (14): the base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene; the solvent selected is dimethyl sulfoxide, N,N-dimethylformamide, dichloromethane or toluene; the reaction temperature is 0-55°C, and the reaction time is 2-8h.

15. The method according to claim 14, wherein In step 6), the compound of formula (13) is condensed to obtain the compound of formula (14). The reaction is carried out under alkaline conditions. The base used is N-methylimidazole; the condensing agent used is N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate; the selected solvent is acetonitrile; the reaction temperature is room temperature; and the reaction time is 12 hours. The compound of formula (13) is subjected to a condensation reaction to obtain the compound of formula (15): the reaction is carried out under alkaline conditions, the base used is N,N-diisopropylethylamine; the condensing agents used are benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate (HBTU) and 1-hydroxybenzotriazole (HOBt); the selected solvent is N,N-dimethylformamide; the reaction temperature is room temperature; the reaction time is 6 hours; The compound of formula (15) is subjected to hydrolysis reaction to obtain the compound of formula (16); the base used is lithium hydroxide; the solvent is methanol and water; the reaction temperature is room temperature; the reaction time is 24 hours; The compound of formula (16) is subjected to an amide condensation reaction to obtain the compound of formula (14); the reaction is carried out under alkaline conditions, the base used is N-methylimidazole; the condensation agent used is N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate; the selected solvent is acetonitrile; the reaction temperature is room temperature; the reaction time is 12 hours; The compound of formula (13) is subjected to ester condensation to obtain the compound of formula (17); the selected succinimide donor is N-hydroxysuccinimide; the selected dehydrating agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI); the solvent is N,N-dimethylformamide; the reaction temperature is 0°C; the reaction time is 2 hours; The compound of formula (17) is subjected to ester aminolysis to obtain the compound of formula (14): the base used is N,N-diisopropylethylamine; the selected solvent is dichloromethane; the reaction temperature is room temperature; and the reaction time is 4 hours.

16. The method according to claim 2, wherein In step 7), the acid used is trifluoroacetic acid, acetic acid, formic acid, trifluoromethanesulfonic acid, hydrochloric acid, hydrobromic acid, sulfuric acid or nitric acid; the solvent selected is ethyl acetate, 1,4-dioxane, dichloromethane or tetrahydrofuran, the reaction temperature is 0-45° C., and the reaction time is 0.5-2 h.

17. The method according to claim 16, wherein In step 7), the acid used is hydrochloric acid, the solvent selected is ethyl acetate, the reaction temperature is room temperature, and the reaction time is 1 h.

18. The method according to claim 2, wherein In step 8), the reaction is carried out under alkaline conditions, and the base used is triethylamine, N,N-diisopropylethylamine, N-methylimidazole or 1,8-diazabicycloundec-7-ene; the solvent is dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, tetrahydrofuran or dichloromethane; the reaction temperature is 0-45° C., and the reaction time is 1-12 h.

19. The method according to claim 18, wherein The reaction is carried out under alkaline conditions, the base used is N,N-diisopropylethylamine; the solvent is N,N-dimethylformamide; the reaction temperature is room temperature; and the reaction time is 8 hours.

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