Tyrosine derivatives, processes for their preparation, starting materials and uses thereof

Abstract

The present application relates to a kind of tyrosine derivatives and its preparation method, preparation raw materials and application.The above-mentioned tyrosine derivative has the following structural formula:Experimental demonstration, the above-mentioned tyrosine derivative is introduced by deuterium in traditional 18 F-tyrosine, which can improve the imaging target ratio and enhance the sensitivity of tumor imaging when used for the preparation of imaging agents.

Description

Technical Field

[0001] This invention relates to the field of imaging technology, and in particular to a tyrosine derivative, its preparation method, raw materials, and applications. Background Technology

[0002] Numerous studies have shown that tumor cells exhibit significant metabolic changes compared to normal cells. To meet their own proliferation needs, tumor cells require large amounts of amino acids. Amino acids are hydrophilic and cannot diffuse freely across mammalian cell membranes; therefore, tumor cells primarily achieve their large-scale amino acid uptake through various overexpressed amino acid transporters. Currently, inhibiting tumor growth by targeting amino acid transporters is a research hotspot in this field. Among the many amino acid transporters, LAT1 (targeting L-type amino acid transporter 1) has been the most studied. Overexpression of LAT1 plays a crucial role in the continuous proliferation of malignant tumor cells and is closely related to tumor stage, tumor angiogenesis, and patient prognosis. Therefore, LAT1-targeted PET (positron emission tomography) probes can be used for tumor imaging.

[0003] Currently, the amino acids used for tumor imaging mainly include 11 C-methionine ( 11 C-MET) and 18 F-tyrosine ( 18 F-FET), but 11 C-MET uses products with shorter half-lives. 11 The C tag has high usage requirements and its use is limited. 18 F-FETs have a longer half-life, but they exhibit some non-specific uptake and have lower imaging sensitivity. Summary of the Invention

[0004] Based on this, some embodiments of the present invention provide a tyrosine derivative and a method for preparing the same, which can be used to prepare a developer and improve the sensitivity of the developer.

[0005] In addition, some other embodiments of the present invention also provide a raw material for the preparation of the above-mentioned tyrosine derivative and its application.

[0006] A tyrosine derivative has the following structural formula:

[0007] .

[0008] A raw material for preparing a tyrosine derivative has the following general structural formula:

[0009] ;

[0010] Where R1 is 18F or OTos, R2 and R3 are each an amino protecting group, and R4 is a carboxyl protecting group.

[0011] In some embodiments, the following structural formula is used: , .

[0012] A method for preparing a tyrosine derivative includes the following steps:

[0013] Connect the precursor with [ 18 The reaction of F] fluoride yields an intermediate;

[0014] The intermediate was deprotected to obtain a tyrosine derivative;

[0015] The structural formulas of the precursor, the intermediate, and the tyrosine derivative are as follows: , and R2 and R3 are each an amino protecting group, and R4 is a carboxyl protecting group.

[0016] In some embodiments, the precursor is combined with [ 18 The steps of the [F] fluoride reaction include: reacting the precursor with [ 18 The F] fluoride mixture is reacted at 120℃~140℃ for 10 min~15 min, cooled to 70℃~85℃, and dried under air for 5 min~7 min to obtain the intermediate.

[0017] In some embodiments, the step of deprotecting the intermediate includes reacting the intermediate with an acidic reagent at 130°C to 150°C for 10 to 15 minutes to obtain a tyrosine derivative.

[0018] In some embodiments, the [ 18 The preparation steps for F] fluorides are as follows: in H2 18 O is in progress 18 O(p, n) 18 F is produced by the reaction. 18 F negative ions, using a solid-phase extraction column to... 18 F negative ions from the H2 18 Separate from O, elute the solid-phase extraction column with tetraethylammonium bicarbonate solution, and dry the eluent to obtain the [ 18 F] Fluorides.

[0019] The application of the tyrosine derivatives described above, or the tyrosine derivatives prepared by the methods described above, in the preparation of imaging agents for tumor detection.

[0020] In some embodiments, the tumor includes one or more of glioma, brain metastases, and oral squamous cell carcinoma.

[0021] A developer comprising the above-described tyrosine derivative or a tyrosine derivative prepared by the above-described preparation method.

[0022] Experiments have shown that the above-mentioned tyrosine derivatives, through traditional methods... 18 The introduction of deuterium into F-tyrosine improves the target-to-sample ratio and enhances tumor imaging sensitivity when used in the preparation of imaging agents. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the ferrule mounting of the All-in-One device used to prepare the tyrosine derivative in Example 1;

[0025] Figure 2 This is a schematic diagram of the synthesis interface of the GE Tracerlab FX2N equipment used to prepare the tyrosine derivative in Example 2;

[0026] Figure 3 This is a purity test result for the tyrosine derivative prepared in Example 1.

[0027] Figure 4 This is a purity test result for the tyrosine derivative prepared in Example 2.

[0028] Figure 5 for 18 In vivo and in vitro studies of F-d4-FET in glioma model mice;

[0029] Figure 6 For glioma patients 18 F-d4-FET and 18 Imaging comparison of F-FET;

[0030] Figure 7 for 18 Imaging studies of F-d4-FET for other tumors. Detailed Implementation

[0031] To facilitate understanding of the present invention, a more comprehensive description of the invention will be provided below in conjunction with specific embodiments. Preferred embodiments of the invention are given in the specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] Unless otherwise stated or in case of contradiction, the terms or phrases used in this invention shall have the following meanings:

[0034] In this invention, "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0035] In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this invention, "one or several" refers to any one, any two, or any two or more of the listed items. "Several" refers to any two or more.

[0037] In this invention, unless otherwise specified, all percentage concentrations refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0038] The terms "optionally" and similar expressions used in this invention refer to embodiments of the invention that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be optional in the same or other circumstances. Furthermore, the description of one or more optional embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0039] When a numerical range is disclosed in this invention, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Further, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Moreover, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed in this invention should be understood to include any and all subranges to which they are incorporated.

[0040] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0041] The terms "comprising" and "having," and any variations thereof, used in embodiments of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.

[0042] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0043] The first aspect of this application provides a tyrosine derivative having the following structural formula:

[0044] .

[0045] The above-mentioned tyrosine derivatives are (recorded as) 18 F-d4-FET), compared with traditional 18 F-tyrosine ( 18 Compared to F-FET, the ethylene derivative is deuterated. Experiments have shown that by introducing deuterium, it can improve the target-to-tumor ratio and tumor imaging sensitivity when used to prepare imaging agents, resulting in better imaging effects and more favorable conditions for determining tumor boundaries. Furthermore, it also has advantages for imaging other types of tumors. Specifically, in vivo and in vitro imaging studies in rodent glioma animal models show that the imaging agent prepared from the aforementioned tyrosine derivative can effectively visualize the tumor extent, with its imaging edges highly consistent with pathological edges. Compared to... 18 F-FET showed its effectiveness in glioma imaging contrast studies.18 F-d4-FET PET images have a higher target-to-substrate ratio and better imaging results, thus making them more effective in determining tumor boundaries. 18 F-d4-FET also demonstrates excellent imaging performance in other tumor models such as oral cancer, lung cancer, and melanoma. Therefore, 18 F-d4-FET has the potential to replace traditional methods in glioma imaging. 18 F-FET also has certain application value in other tumors.

[0046] The second aspect of this application provides a raw material for preparing a tyrosine derivative, having the following general structural formula:

[0047] ;

[0048] Where R1 is 18 F or OTos, R2 and R3 are each an amino protecting group, and R4 is a carboxyl protecting group.

[0049] In some embodiments, the amino protecting group may be, but is not limited to, Boc (tert-butoxycarbonyl), Bn (benzyl), Cbz (benzyloxycarbonyl), Tos (p-toluenesulfonyl), PMB (p-methoxybenzyl), or Pht (phthalyl). In some embodiments, the amino protecting group is Boc.

[0050] In some embodiments, R2 and R3 are the same.

[0051] In some embodiments, the carboxyl protecting group can be one commonly used in the art, for example, R4 is a C1-C6 alkyl group. In some embodiments, R4 is a methyl group.

[0052] In some embodiments, the structural formula of the raw material for preparing tyrosine derivatives is as follows: , .

[0053] The above-mentioned raw materials can be used as precursors or intermediates to prepare tyrosine derivatives.

[0054] A third aspect of this application provides a method for preparing a tyrosine derivative, comprising the following steps:

[0055] Connect the precursor with [ 18 The reaction of F] fluoride yields an intermediate;

[0056] The intermediate was deprotected to obtain a tyrosine derivative;

[0057] The structural formulas of the precursor, the intermediate, and the tyrosine derivative are as follows: , and R2 and R3 are each an amino protecting group, and R4 is a carboxyl protecting group.

[0058] In some embodiments, the precursor has the following structural formula: The synthetic route of the precursor is as follows:

[0059] .

[0060] Specifically, the preparation steps of the precursor include:

[0061] Compound 1 was reacted with p-toluenesulfonyl chloride (TsCl) under alkaline conditions and in the presence of a first catalyst to prepare compound 2. The reagent used under alkaline conditions may be, but is not limited to, triethylamine (TEA), and the first catalyst may be, but is not limited to, 4-dimethylaminopyridine (DMAP).

[0062] Compound 3 was reacted with compound 2 under alkaline conditions and a phase transfer catalyst to prepare compound 4. The reagent used under alkaline conditions may be, but is not limited to, potassium carbonate (K2CO3), and the phase transfer catalyst may be, but is not limited to, 18-crown-6.

[0063] The precursor is prepared by reacting compound 4 with di-tert-butyl carbonate anhydride (Boc2O) under alkaline conditions and in the presence of a second catalyst. The reagent used under alkaline conditions may be, but is not limited to, triethylamine (TEA), and the second catalyst may be, but is not limited to, 4-dimethylaminopyridine (DMAP).

[0064] It is understandable that when R2 and R3 are other amino protecting groups and R4 is other carboxyl protecting groups in the precursor's structural formula, it can be prepared by referring to the above reaction, and will not be repeated here.

[0065] In some embodiments, the precursor is combined with [ 18 The steps of the [F] fluoride reaction include: reacting the precursor with [ 18 The F] fluoride mixture is reacted at 120℃~140℃ for 10 min~15 min, cooled to 70℃~85℃, and dried under air for 5 min~7 min to obtain the intermediate.

[0066] In some embodiments, the precursor is combined with [ 18 The F] fluoride reaction is carried out in an organic solvent. The organic solvent can be, but is not limited to, acetonitrile (CH3CN).

[0067] It's understandable. 18 F] Fluorides can be prepared by methods commonly used in the art, and are not particularly limited herein.

[0068] In some of these embodiments, [18 F] Fluorides include 18 F-TEAF ([ 18 F]Et4NF). Specifically, [ 18 F] Fluorides are 18 A mixture of F-TEAF and TEAB (tetraethylammonium bicarbonate).

[0069] In an optional example, [ 18 F] fluorides are prepared by the following steps: in H2 18 O is in progress 18 O(p, n) 18 F is produced by the reaction. 18 F negative ions, using a solid-phase extraction column to... 18 F negative ions from the H2 18 Separate from O, elute the solid-phase extraction column with tetraethylammonium bicarbonate solution, and dry the eluent to obtain the [ 18 F] Fluorides.

[0070] Specifically, using a cyclotron in H2 18 On O 18 O(p,n) 18 F is produced by the reaction. 18 F negative ions.

[0071] In an optional example, for those containing [ 18 The step of drying the eluent containing [F] fluoride includes: drying the eluent containing [F] fluoride. 18 The eluent for F fluoride was heated to 110 °C and evaporated under dry nitrogen for 2 min. Then acetonitrile was added, and the eluent was evaporated and dried at 110 °C for 100 s, at 100 °C for 100 s, and at 90 °C for 2 min. These steps thoroughly removed water from the eluent, avoiding side reactions caused by the presence of water.

[0072] In another optional example, for those containing [ 18 The steps for drying the eluent of fluoride F include: evaporating at 85°C for 3 min, then adding acetonitrile, and evaporating at 65°C and 110°C for 10 min each.

[0073] In one embodiment, the solvent used in the tetraethylammonium bicarbonate (TEAB) eluent includes one or more of water, acetonitrile, and ethanol. In an optional example, the solvent used in the TEAB eluent is a mixture of water and acetonitrile, or a mixture of water and ethanol.

[0074] In some embodiments, the step of deprotecting the intermediate to obtain the tyrosine derivative includes: reacting the intermediate with an acidic reagent at 130°C to 150°C for 10 to 15 minutes to obtain the tyrosine derivative. Under the action of the acidic reagent, the carboxyl protecting group is removed, and the amino protecting group is also removed.

[0075] In some embodiments, the acidic reagent may be, but is not limited to, hydrochloric acid.

[0076] The above-mentioned method for preparing tyrosine derivatives can achieve high radiochemical yield and high radioactive purity synthesis of drugs on two commercially available automated devices (All-in-One and GE Tracerlab FX2N), enabling institutions to independently synthesize and supply them for clinical use. Furthermore, the prepared tyrosine derivatives... 18 Both F-d4-FETs meet the quality standards for injectable positron emission tomography (PET) drugs and are of great significance for imaging tumors, especially central nervous system tumors.

[0077] The fourth aspect of this application provides the use of the tyrosine derivative as described above or the tyrosine derivative prepared by the preparation method described above in the preparation of an imaging agent for tumor detection.

[0078] In some embodiments, the tumor includes one or more of glioma, brain metastases, and oral squamous cell carcinoma.

[0079] Specifically, brain metastases can be, but are not limited to, lung cancer, melanoma, or fibrosarcoma. Oral squamous cell carcinoma can be, but is not limited to, tongue cancer.

[0080] Experiments have demonstrated that, in in vivo and in vitro imaging studies using rodent glioma animal models, the imaging agent prepared from the aforementioned tyrosine derivative can effectively visualize the tumor extent, with the imaging margins highly consistent with the pathological margins. In conjunction with... 18 F-FET showed its effectiveness in glioma imaging contrast studies. 18 F-d4-FET PET images have a higher target-to-substrate ratio and better imaging results, thus making them more effective in determining tumor boundaries. 18 F-d4-FET also demonstrates excellent imaging performance in other tumor models such as oral cancer, lung cancer, and melanoma. Therefore, 18 F-d4-FET has the potential to replace traditional methods in glioma imaging. 18 F-FET also has certain application value in other tumors.

[0081] A fifth aspect of this application provides a developer comprising the above-described tyrosine derivative or a tyrosine derivative prepared by the above-described preparation method.

[0082] It is understood that the developer may also include at least one pharmaceutically acceptable excipient. For example, the excipient may be one of a carrier, a filler, or a solvent.

[0083] To make the objectives and advantages of the present invention clearer, the tyrosine derivatives and their effects of the present invention are further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and should not be used to limit the present invention. Unless otherwise specified, the following embodiments do not include components other than unavoidable impurities. Unless otherwise specified, the drugs and instruments used in the embodiments are conventional choices in the art. Experimental methods in the embodiments that do not specify specific conditions are implemented according to conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0084] The preparation steps of the precursors in the following examples are as follows:

[0085] (1)

[0086] At room temperature, compound 1 (1 g, 15.13 mmol, 1 eq) was added to DCM (60 ml, 60 V), followed by DMAP (924 mg, 7.565 mmol, 0.5 eq), TEA (4.6 g, 6.3 ml, 45.39 mmol, 3 eq), and TsCl (6.35 g, 33.286 mmol, 2.2 eq, added in portions). After the addition of TsCl, the reaction system changed from colorless and clear to yellow and clear, and then became cloudy. The reaction was carried out at room temperature for 2 h. The reaction was considered complete by TLC (the mobile phase used for TLC was PE / EA = 3 / 1, and the R of compound 1 was [missing value]. f = 0, phosphomolybdic acid shows color development; R of compound 2 f = 0.5). Add water (60 mL) and separate the phases. Extract the aqueous phase twice with DCM (50 mL the first time, 20 mL the second time). Wash the combined organic phase once with 30 mL of saturated brine, dry with anhydrous sodium sulfate, and concentrate under reduced pressure at 40 °C to obtain the crude product. Add 10 mL of methanol to the crude product, stir at room temperature for 5 minutes, then filter, collect the filter cake, and give compound 2 (5.14 g pale yellow solid, 90.67% yield). HRMS calculated for C 16 H 15 D4O6S2 (M + H + ): 375.4664, found 375.4671.

[0087] (2)

[0088] Compound 3 (0.875 g, 2.96 mmol, 1 eq) was dissolved in anhydrous acetonitrile (60 mL, 68 V), and compound 2 (1.4 g, 3.73 mmol, 1.26 eq), potassium carbonate (0.92 g, 6.63 mmol, 2.24 eq), and 18-crown-6 (179 mg, 0.59 mmol, 0.2 eq) were added. The mixture was heated to reflux overnight. Samples were taken for TLC analysis. The reaction was considered complete at this point. (The mobile phase used for TLC analysis was DCM / EA = 40 / 1, and the R0 of compound 2 was [not specified].) f = 1, R of compound 3 f = 0.1, R of compound 4 f = 0.2). The reaction system was cooled and concentrated under reduced pressure to remove MeCN. It was then extracted with H2O (20 mL) and EA (ethyl acetate, 20 mL). The organic phase was washed once with saturated brine (10 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by MPLC (mobile phase adjusted from DCM to DCM / EA = 20 / 1) to give compound 4 (1 g, pale yellow, oily, viscous sample, 67.8% yield). HRMS calculated for C 24 H 28 D4NO8S (M + H + ): 498.2100, found 498.2111.

[0089] (3)

[0090] Compound 4 (730 mg, 1.467 mmol, 1 eq) was dissolved in DCM (1.5 ml, 2V), and TEA (14.6 ml, 20V), DMAP (35 mg, 0.29 mmol, 0.2 eq), and Boc2O (1.28 g, 5.87 mmol, 4 eq) were added. The mixture was stirred overnight at 25°C. Samples were taken for TLC analysis. The reaction was considered complete at this point (the mobile phase used for TLC analysis was DCM / EA = 40 / 1, and the R0 of compound 4 was [missing value]. f = 0.2, R of the precursor f = 0.25). Add 10% citric acid aqueous solution to the reaction system until the pH is neutral. Add DCM (15 mL * 3). Combine the organic phases and wash once with saturated brine (15 mL). Dry with anhydrous sodium sulfate, filter, and concentrate under reduced pressure to obtain the crude product. Purify by MPLC (mobile phase adjusted from PE to DCM / EA = 30 / 1) to obtain the precursor (1.6 g yellow oily viscous sample, 77% yield). HRMS calculated for C29 H 36 D4NO 10 S (M + H + ): 598.2624, found 598.2629.

[0091] Example 1

[0092] This embodiment provides a method for preparing tyrosine derivatives using an all-in-one device, comprising the following steps:

[0093] (1) [ 18 F] Fluoride Synthesis

[0094] F-18 negative ions are produced by bombarding H2 with proton beams in a medical cyclotron. 18 O2 is generated and transported to the All-in-One device via pipeline. A Waters Sep-Pak Light QMA solid-phase extraction column (Tianjin Dexiang Maolong Technology Co., Ltd., 186004051, SEP-PAK LIGHTQMA 50BX) is activated with sodium bicarbonate aqueous solution (7.3% by mass) and sterile water for injection, respectively, and then used to capture and separate H2. 18 F-18 negative ions in O. 1 mL of TEAB (tetraethylammonium bicarbonate) eluent was automatically drawn using a 3 mL syringe. The solvent was a mixture of 0.7 mL CH3CN (acetonitrile) and 0.3 mL H2O. This mixture was used to elute the solid-phase extraction column, and the eluent was transferred to a reaction flask.

[0095] The reaction flask was heated to 110 °C while being purged with dry nitrogen gas for 2 min to evaporate and dry it. Then, 1 mL of acetonitrile was added to the reaction flask, and the reaction was continued to be purged with dry nitrogen gas at 110 °C for 100 s, at 100 °C for 100 s, and at 90 °C for 2 min to obtain the desired result. 18 The F-TEAF / TEAB mixture was then cooled to 50 °C.

[0096] (2) Intermediate synthesis

[0097]

[0098] 1.2 mg of the precursor (dissolved in 1.3 mL of CH3CN) was added to the reaction flask of step (1), and the reaction flask was heated to 120 °C and reacted for 10 min. Then the temperature was lowered to 85 °C, and the mixture was dried by aeration for 5 min. The reaction flask was then cooled to 50 °C to obtain the intermediate.

[0099] (3) Synthesis of tyrosine derivatives

[0100] Add 1 mL of 3M HCl to the reaction flask from step (2) and react at 130°C for 10 min to obtain the tyrosine derivative. Then cool the reaction flask to 40°C and add 3 mL of 1.2 M NaOAc to the reaction flask. Use a syringe to aspirate the solution in the reaction flask to ensure complete neutralization.

[0101] (4) HPLC separation and purification

[0102] Draw 4 mL of solution from the reaction flask and insert it into the loop. To reduce the loss of product in the reaction flask, draw 4 mL of buffer A (5% ethanol) and inject it back into the reaction flask, then draw it out again and insert it into the loop.

[0103] Instrument: Shimadzu LC-16P high performance liquid chromatograph (Japan);

[0104] Detector: Detection was performed jointly by a Shimadzu ultraviolet detector (SPD-16, λ = 254 nm) and a radioactive detector;

[0105] Semi-preparative chromatographic column: OSAKA SODA CAPCELL PAK C18, 5 μm, 10 mm ID × 250 mm;

[0106] Column temperature: 20 ℃;

[0107] Mobile phase solution: CH3CH2OH / H2O = 5 / 95;

[0108] Flow rate: 5 ml per minute;

[0109] Product retention time: 15 min.

[0110] The schematic diagram of the ferrule installation of the All-in-One device used to prepare the tyrosine derivative in this embodiment is shown below. Figure 1 As shown. This is understandable. Figure 1 This refers to the layout interface of the All-in-One device. When the device is working, specific parameter values ​​can be provided as needed.

[0111] Example 2

[0112] This embodiment provides a method for preparation using a GE Tracerlab FX2N device (a multifunctional fluorine synthesis device), with the following steps:

[0113] (1) [ 18 F] Fluoride Synthesis

[0114] Fluorine-18 negative ions are produced by bombarding H2 with a proton beam in a medical cyclotron accelerator. 18O2 is generated and transported via pipeline to a GE Tracerlab FX2N device. A Waters Sep-Pak Light QMA solid-phase extraction column (Tianjin Dexiang Maolong Technology Co., Ltd., 186004051, SEP-PAK LIGHT QMA 50BX) is activated with sodium bicarbonate aqueous solution (7.3% by mass) and sterile water for injection, respectively, and then used to capture and separate H2. 18 Fluorine-18 anions in O were elute with the eluent from V1 (containing 2 mg TEAB + 0.7 mL anhydrous acetonitrile + 0.3 mL sterile water) into reaction flask 1. The flask was then evaporated at 85 °C for 3 min. Then, the liquid from V2 (1 mL acetonitrile) was added to reaction flask 1, and the flask was evaporated at 65 °C and 110 °C for a total of 10 min. The reaction flask was then cooled to 50 °C.

[0115] (2) Synthesis of intermediates

[0116]

[0117] 1.2 mg of the precursor was dissolved in 1.3 mL of ACN and placed in V3, then added to reaction flask 1. The mixture was heated to 120 °C and reacted for 10 min. The mixture was then cooled to 85 °C and dried under ventilation for 5 min. Subsequently, reaction flask 1 was cooled to 50 °C.

[0118] (3) Synthesis of tyrosine derivatives

[0119] 1 mL of 3 M HCl from V4 was added to reaction flask 1, and the mixture was reacted at 130 °C for 10 min to obtain a tyrosine derivative. The reaction flask was then cooled to 40 °C, and 1 mL of 3.6 M NaOAc from V5 was added to reaction flask 1 to neutralize the excess HCl.

[0120] (4) HPLC separation and purification

[0121] Take 2 mL of product from reaction flask #1 and inject it into the loop.

[0122] Instrument: Shimadzu LC-16P high performance liquid chromatograph (Japan);

[0123] Detector: Detection was performed jointly by a Shimadzu ultraviolet detector (SPD-16, λ = 225 nm) and a radioactive detector;

[0124] Semi-preparative chromatographic column: OSAKA SODA CAPCELL PAK C18, 5 μm, 10 mm ID × 250 mm;

[0125] Column temperature: 20 ℃;

[0126] Mobile phase solution: CH3CH2OH / H2O = 5 / 95;

[0127] Flow rate: 5 ml / min;

[0128] Product retention time: 10.7 min.

[0129] The synthesis interface diagram of the tyrosine derivative prepared in this embodiment is shown in the figure below. Figure 2 As shown.

[0130] The following is the test section:

[0131] 1. Purity testing

[0132] Instrument: Shimadzu LC-16P high performance liquid chromatograph (Japan);

[0133] Detector: Detection was performed jointly by a Shimadzu ultraviolet detector (SPD-16, λ = 225 nm) and a radioactive detector;

[0134] Analytical column: GL Sciences, WondaSil C18-WR, 4.6 × 150 mm;

[0135] Column temperature: 20 ℃;

[0136] Mobile phase solution: CH3CN (0.1% TFA) / H2O (0.1% TFA) = 15 / 85;

[0137] Flow rate: 1 mL / min;

[0138] Retention time of radioactive products and standard compounds: 7.2 ~ 7.5 min.

[0139] The HPLC chromatogram of the tyrosine derivative prepared in Example 1 is shown below. Figure 3 As shown. From Figure 3 It can be seen that the retention time of the radioactive product is 7.224 min and the radiochemical purity is 100%.

[0140] The HPLC chromatogram of the tyrosine derivative prepared in Example 2 is shown below. Figure 4 As shown. From Figure 4 It can be seen that the retention time of the radioactive product is 7.485 min and the radiochemical purity is 100%.

[0141] 3. 18 In vivo and in vitro studies of F-d4-FET in glioma animal models

[0142] Approximately 20 MBq of the drug was injected into SD model rats via the tail vein. Twenty minutes later, PET / CT imaging of the rat brain was performed, and the results were fused with T2-weighted MRI images from the same day. The extent of the lesions shown on the MRI was analyzed. 18 The F-d4-FET PET / CT images were almost identical. After imaging, the mice were euthanized, and immediately embedded and sectioned using OCT. Adjacent brain slices were stained with phosphorus screen and HE staining, respectively. The autoradiographic images and pathological images were then compared. Figure 5 As shown, 18 F-d4-FETs showed significant concentration at the tumor site, with the extent almost identical to that shown by hematoxylin and eosin (HE). The results indicate that... 18 F-d4-FET can effectively visualize the extent of gliomas.

[0143] 4. 18 F-d4-FET and 18 Comparative Imaging Study of F-FET in Glioma Patients

[0144] Figure 6 MRI enhancement at the same level in the brain of a patient suspected of having a glioma. 18 F-d4-FET and 18 F-FET imaging representative image; the patient underwent contrast-enhanced brain MRI and [other imaging techniques] within one week. 18 F-d4-FET, 18 Two PET / CT scans were performed using the F-FET method, with an interval of at least 24 hours between the two scans. The patient underwent tumor resection after the PET scans, and pathological diagnosis confirmed a diffuse midline glioma, WHO grade IV. Figure 6 As shown, a mass is present in the left temporal lobe-thalamus-basal ganglia region, with significant enhancement on MRI. Abnormal radioactive concentrations of both imaging agents are observed within the enhanced area, and the imaging range of both PET scans is larger than the enhanced area on MRI. However, within normal brain tissue, 18 F-FETs still exhibit some non-specific uptake, therefore, 18 F-d4-FET has a higher target-to-substrate ratio, and its imaging effect is significantly better than that of FET. 18 F-FET provides a clearer delineation of the tumor's extent, which is more helpful in assisting clinical diagnosis and treatment.

[0145] 5. 18 Imaging studies of F-d4-FET in other tumor models

[0146] Figure 7 Demonstrated the use in different tumor models 18F-d4-FET imaging was performed, showing from left to right two subcutaneous lung cancer models (H460 and A549), a subcutaneous melanoma model (B16F10), a subcutaneous fibrosarcoma model (HT1080), and an in situ tongue cancer model (cal27). The white arrows indicate the location of the tumor. Among these models, 18 F-d4-FETs were significantly concentrated in tumor tissues, which indicates that... 18 F-d4-FET has imaging potential for these tumors.

[0147] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0148] The embodiments described above are merely illustrative of several implementations of the present invention, facilitating a detailed understanding of the technical solutions of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A tyrosine derivative, characterized in that, It has the following structural formula: The tyrosine derivative is used for imaging of tumors of the central nervous system.

2. A raw material for preparing the tyrosine derivative as described in claim 1, characterized in that, It has the following general structural formula: ； Where R1 is 18 F or OTos, R2 and R3 are each independently an amino protecting group, and R4 is a carboxyl protecting group. The amino protecting group is tert-butoxycarbonyl, benzyl, benzyloxycarbonyl, p-toluenesulfonyl, p-methoxybenzyl, or phthaloyl, and the carboxyl protecting group is a C1-C6 alkyl group.

3. The raw material for preparing the tyrosine derivative according to claim 2, characterized in that, It has the following structural formula: , .

4. A method for preparing the tyrosine derivative as described in claim 1, characterized in that, Includes the following steps: Connect the precursor with [ 18 The reaction of F] fluoride yields an intermediate; The intermediate was deprotected to obtain a tyrosine derivative; The structural formulas of the precursor, the intermediate, and the tyrosine derivative are as follows: , and R2 and R3 are each an amino protecting group, and R4 is a carboxyl protecting group. The amino protecting group is tert-butoxycarbonyl, benzyl, benzyloxycarbonyl, p-toluenesulfonyl, p-methoxybenzyl, or phthaloyl, and the carboxyl protecting group is a C1-C6 alkyl group.

5. The method for preparing the tyrosine derivative according to claim 4, characterized in that, Connect the precursor with [ 18 The steps of the [F] fluoride reaction include: reacting the precursor with [ 18 The F] fluoride mixture is reacted at 120℃~140℃ for 10 min~15 min, then cooled to 70℃~85℃ and dried under air for 5 min~7 min to obtain the intermediate.

6. The method for preparing the tyrosine derivative according to claim 4, characterized in that, The step of deprotecting the intermediate includes reacting the intermediate with an acidic reagent at 130°C to 150°C for 10 min to 15 min.

7. The method for preparing the tyrosine derivative according to claim 4, characterized in that, The [ 18 The preparation steps for F] fluorides are as follows: in H2 18 O is in progress 18 O(p, n) 18 F is produced by the reaction. 18 F negative ions, using a solid-phase extraction column to... 18 F negative ions from the H2 18 Separate from O, elute the solid-phase extraction column with tetraethylammonium bicarbonate solution, and dry the eluent to obtain the [ 18 F] Fluorides.

8. The use of the tyrosine derivative as described in claim 1 or the tyrosine derivative prepared by any one of claims 4 to 7 in the preparation of an imaging agent for the detection of tumors of the central nervous system.

9. The application according to claim 8, characterized in that, The tumor includes one or more of gliomas and brain metastases.

10. An imaging agent for detecting tumors of the central nervous system, characterized in that, This includes the tyrosine derivative as described in claim 1 or the tyrosine derivative prepared by any one of the preparation methods described in claims 4 to 7.

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