Small molecule compound targeting folate receptor, preparation method, composition, and use

Abstract

The present invention provides a small molecule compound targeting a folate receptor, a preparation method, a composition, and a use. Specifically provided is a compound represented by formula (I) or a pharmaceutically acceptable salt thereof. The compound or the pharmaceutically acceptable salt thereof provided by the present invention can be used as a small molecule targeted fluorescent contrast agent for adjuvant surgical treatment, and has a novel structure and good targeting performance. A near infrared fluorescence capture system provided by the present invention facilitates tumor diagnosis and treatment and has good application prospects.

Description

Small molecule compound targeting folate receptor and preparation method, composition and application thereof

[0001] This application claims priority to Chinese Patent Application No. 202411130803.9, filed on August 16, 2024, and Chinese Patent Application No. 202411130802.4, filed on August 16, 2024. This application incorporates the entirety of the above-mentioned Chinese Patent Applications. TECHNICAL FIELD

[0002] The present application relates to a technology for detecting and evaluating the functional activity on tumors, in particular to a small molecule compound targeting folate receptor and preparation method, composition and application thereof. BACKGROUND

[0003] Folate receptor alpha (FR-α), also known as FOLR1 or folate binding protein, is a glycoprotein anchored on the cell membrane by glycosylated phosphatidylinositol (GPI), has high affinity for folic acid, and can transport folic acid through receptor-mediated endocytosis. FRα promotes tumor malignant growth as a signal molecule. Similar to other glycosylated phosphatidylinositol family proteins, FRα initiates intracellular regulatory signal networks after binding to folic acid. FRɑ is mainly highly expressed in tumor tissues of epithelial origin, and is not expressed or has very low expression in normal tissues, has high affinity for folic acid, and has lower affinity for reduced folic acid.

[0004] It is known that FRα is overexpressed on the entire tumor cell surface of various cancers, including ovarian cancer, TNBC (triple-negative breast cancer), endometrial cancer, mesothelioma, and lung cancer. FRα has a low expression level in normal cells, but a significantly increased expression level in certain cancer cells, and has become an important target in cancer diagnosis and treatment in recent years.

[0005] Intraoperative near-infrared (NIR) fluorescence imaging helps surgeons make judgments and reduce the positive rate of surgical margins, and has become an effective solution for detecting intraoperative tumor margins. Intraoperative fluorescence imaging is based on the enrichment of fluorescein in specific tissues, which can accurately display information such as blood vessels, lymph nodes, and tumor tissues during surgery. At the same time, it can specifically visualize the overexpressed specific molecular targets in tumor tissue, thereby achieving the effect of high signal-to-noise ratio tumor imaging and further reducing the positive rate of surgical margins. The wavelength range of near-infrared light is 650nm to 900nm, and because its penetration depth in tissue can reach 10mm, it is superior to visible light in intraoperative imaging. Because tissues only show limited autofluorescence in the NIR spectrum, using NIR fluorescence imaging agents can maximize the contrast between fluorescent signals in tumors and healthy tissues. In addition, near-infrared light does not affect the surgical field because near-infrared light is invisible to the human eye. The currently available imaging system combines white light illumination of the surgical area with NIR fluorescence images, while providing surgeons with anatomical information and fluorescence information.

[0006] ICG can distinguish various types of adrenal lesions (pheochromocytoma, metastatic renal cell carcinoma (RCC), lymphangioma, adrenal cortical adenoma, adrenal hemorrhagic cyst, adrenal simple cyst, cystic lymphangioma) and perform safe adrenal-sparing surgery.

[0007] The prior art compound OTL38 realizes application in tumor treatment. However, because the conjugation of the structure is too strong, the binding of the molecule and the targeted protein is hindered.

[0008] Therefore, it is particularly important to develop a compound with strong targeting and strong tumor detection capability, which is more suitable for clinical application, and a near-infrared fluorescence capture system. SUMMARY

[0009] The purpose of the present application is to provide a small molecule compound targeting folate receptor and a preparation method, composition and application thereof. As a small molecule targeted fluorescence contrast agent that can effectively assist surgical treatment, the structure is novel, the targeting is strong, and the field of view of the diseased tissue in tumor surgery and other treatment activities can be significantly improved, helping to efficiently and effectively identify diseased tissue and normal tissue, thereby facilitating surgical treatment.

[0010] The present application solves the above technical problems through the following scheme.

[0011] The present application provides a compound shown in formula I or a pharmaceutically acceptable salt thereof.

[0012] wherein,

[0013] R is

[0014] In one aspect, R is For example

[0015] In one aspect, the compound of Formula I is any one of the following compounds:

[0016] n is 2, 3, 4, or 5

[0017] m is 1, 2, 3, or 4

[0018] .

[0019] In one aspect, the pharmaceutically acceptable salt of the compound of Formula I contains a pharmaceutically acceptable cation, and the number of cations can be 1, 2, 3, or 4, and the cation can be K + , Na + , Li + , or NH4 + , for example, the tetrasodium salt of the compound of Formula I.

[0020] In one aspect, the compound of Formula I or a pharmaceutically acceptable salt thereof is a small molecule compound targeting folate receptor.

[0021] In one aspect, the pharmaceutically acceptable salt of the compound of Formula I is a compound of Formula II:

[0022] wherein M 1 , M 2 , M 3 , and M 4 are each independently H or a pharmaceutically acceptable cation;

[0023] R is as described in any aspect of the present application.

[0024] In one aspect, the pharmaceutically acceptable cation is a monovalent cation, for example, K + , Na + , or Li + , preferably Na + .

[0025] To achieve the above object, the embodiments of the present application provide a small molecule compound targeting folate receptor, which is:

[0026] wherein M is a monovalent cation, and R is selected from wherein denotes the position of the covalent bond of the R group.

[0027] In one or more embodiments of the present application, the monovalent cation is selected from the group consisting of potassium ion, sodium ion, lithium ion (e.g., sodium ion).

[0028] In one or more embodiments of the present application, the small molecule compound targeting folate receptor is wherein M is potassium ion, sodium ion, lithium ion (e.g., sodium ion).

[0029] In one or more embodiments of the present application, the small molecule compound targeting folate receptor is wherein M 1 , M 2 , M 3 , and M 4 are independently K + , Na + , or Li + (e.g., Na + ).

[0030] In one or more embodiments of the present application, the small molecule compound targeting folate receptor is

[0031] n is 2, 3, 4, or 5

[0032] m is 1, 2, 3, or 4

[0033] .

[0034] The present application provides a method for preparing the above-mentioned small molecule compound targeting folate receptor, the above-mentioned compound of formula I, or a pharmaceutically acceptable salt thereof, characterized in that it comprises the following steps:

[0035] preparing a first intermediate having the following structural formula:

[0036] reacting the first intermediate with a first compound to obtain the target compound, wherein the first compound has the following structural formula: wherein M 2 , M 3 , M 4 are each independently H or a pharmaceutically acceptable cation (e.g., monovalent cation), and R is selected from the group consisting of

[0037] In one or more embodiments of the present application, the method for preparing the small molecule compound targeting folate receptor is characterized in that it comprises the following steps:

[0038] preparing a first intermediate having the following structural formula:

[0039] The first intermediate is reacted with the first compound to obtain the target compound, and the first compound is wherein M is a monovalent cation, and R is selected from

[0040] In one or more embodiments of the present application, the reaction of the first intermediate with the first compound is carried out in an aqueous carbonate solution. Preferably, the concentration of the aqueous carbonate solution is 3-10 wt.%. Preferably, the aqueous carbonate solution is a 3.35 wt.% sodium carbonate solution.

[0041] In one or more embodiments of the present application, the carbonate is selected from sodium carbonate, potassium carbonate.

[0042] In one or more embodiments of the present application, the reaction conditions are 70-75 °C.

[0043] In one aspect, the reaction conditions are 70-75 °C, and the reaction is carried out for 1-2 h.

[0044] The present application also provides a compound of formula V or a pharmaceutically acceptable salt thereof:

[0045] wherein R is as defined in any aspect of the present application.

[0046] Preferably, the compound of formula V is any one of the following compounds:

[0047] n is 2, 3, 4 or 5

[0048] m is 1, 2, 3 or 4

[0049] .

[0050] The present application also provides a pharmaceutical composition comprising the small molecule compound targeting folate receptor as described above. Preferably, the active ingredient of the pharmaceutical composition is selected from the small molecule compound targeting folate receptor or a pharmaceutically acceptable salt thereof, a conjugate thereof and a pharmaceutically acceptable salt thereof. The composition can adopt a dosage form suitable for intradermal, subcutaneous, intramuscular, intraperitoneal, intravenous and intrathecal administration.

[0051] The present application also provides a pharmaceutical composition comprising the compound of formula I or a pharmaceutically acceptable salt thereof, the small molecule compound targeting folate receptor as described above and a pharmaceutical excipient. Preferably, the pharmaceutically acceptable salt is the compound of formula II. Preferably, the compound of formula I or a pharmaceutically acceptable salt thereof, the small molecule compound targeting folate receptor are active ingredients.

[0052] In one or more embodiments of the present application, the use of the application, including the small molecule compound targeting folate receptor as described above or the composition as described above, in the targeted reagent for targeting cancer tissue. The reagent includes detection reagent, therapeutic preparation.

[0053] In one or more embodiments of the present application, the cancer tissue is a cancer tissue expressing folate receptor, which can include parenchymal tissue or interstitial tissue or marginal tissue, such as lung cancer, breast cancer, ovarian cancer, etc.

[0054] The present application provides a use of the compound of formula I or its pharmaceutically acceptable salt as described above, or the small molecule compound targeting folate receptor as described above, in the preparation of a medicament for treating or diagnosing cancer tissue. Preferably, the medicament is an imaging agent (such as a fluorescent contrast agent).

[0055] The cancer tissue can be a cancer tissue expressing folate receptor, which can include parenchymal tissue or interstitial tissue or marginal tissue, such as lung cancer, breast cancer or ovarian cancer.

[0056] The present application provides a near-infrared fluorescence capture system, which comprises an imaging module containing the compound of formula I or its pharmaceutically acceptable salt;

[0057] wherein,

[0058] R is

[0059] In a certain aspect, the imaging module is used to provide the compound of formula I or its pharmaceutically acceptable salt to the target lesion area.

[0060] In a certain aspect, the imaging module comprises an imaging agent, which comprises the compound of formula I or its pharmaceutically acceptable salt and the above-mentioned pharmaceutical adjuvant, the pharmaceutical adjuvant is selected from one or more of the following: pharmaceutically acceptable carrier, diluent, pH adjuster, pH buffer, osmotic pressure regulator, solubilizer, metal ion chelator and antioxidant, for example, it comprises water for injection, osmotic pressure regulator, pH adjuster and / or buffer, the osmotic pressure regulator such as NaCl, the pH buffer such as potassium / sodium dihydrogen phosphate and dipotassium / sodium hydrogen phosphate, citric acid and citrate; the pH adjuster such as hydrochloric acid and / or sodium hydroxide; the metal ion chelator such as EDTA-2Na; the antioxidant such as sodium sulfite.

[0061] In a certain aspect, the near-infrared fluorescence capture system further comprises a light source module and a signal acquisition and display module.

[0062] The signal acquisition and display module is conventional in the art, which can include a near-infrared visual capture device with a near-infrared camera and a display device, through which the fluorescent signal emitted by the imaging agent is acquired and displayed on the display device.

[0063] The camera is conventional in the art, for example, the camera can simultaneously receive visible light and near-infrared light.

[0064] The mirror of the signal acquisition and display module is conventional in the art, for example, an optical endoscope or an electronic endoscope. The electronic endoscope is, for example, a flexible endoscope or a fiber endoscope.

[0065] The configuration of the near-infrared camera is conventional in the art, for example, detecting visible light or near-infrared light with absorption and emission maximum between about 400 nm and 900 nm.

[0066] The light source module is conventional in the art, which can be used to provide visible light or near-infrared excitation light to the lesion area, which is the target tissue cell of the imaging agent. The wavelength of the near-infrared excitation light is conventional in the art, for example, 776-805 nm.

[0067] The lesion area can be folate receptor-expressing tissue cells and / or cancer tissue, and the folate receptor-expressing tissue cells can be cancer tissue, including parenchymal tissue, interstitial tissue, or marginal tissue. The cancer tissue is, for example, lung cancer, breast cancer (such as triple-negative breast cancer (TNBC)), ovarian cancer, endometrial cancer, or mesothelioma.

[0068] In an embodiment, the preparation method of the imaging agent comprises the following steps: mixing and dissolving (e.g., dissolving and filtering) the pharmaceutical excipients and the compound of formula I or a pharmaceutically acceptable salt thereof, sterilizing to obtain the imaging agent.

[0069] In an embodiment, the near-infrared fluorescence capture system further comprises a power supply for powering the light source module, the imaging module, and the signal acquisition and display module.

[0070] In an embodiment, R is For example,

[0071] In an embodiment, the compound of formula I is any one of the following compounds:

[0072] n is 2, 3, 4, or 5

[0073] m is 1, 2, 3, or 4

[0074] .

[0075] In one aspect, the pharmaceutically acceptable salt of the compound of Formula I contains one, two, three or four pharmaceutically acceptable cations, which can be K + , Na + , Li + , or NH4 + , such as the tetrasodium salt of the compound of Formula I.

[0076] In one aspect, the pharmaceutically acceptable salt of the compound of Formula I is a compound of Formula II:

[0077] wherein M 1 , M 2 , M 3 and M 4 are each independently H or a pharmaceutically acceptable cation.

[0078] R is as described in any aspect of the application.

[0079] In one aspect, the pharmaceutically acceptable cation is K + , Na + , or Li + .

[0080] In one aspect, the compound of Formula II is

[0081] wherein M 1 , M 2 , M 3 and M 4 are independently K + , Na + , or Li + .

[0082] In one aspect, the compound of Formula II is

[0083] n is 2, 3, 4 or 5

[0084] m is 1, 2, 3 or 4

[0085] .

[0086] The application provides use of the above near-infrared fluorescent capturing system in surgery guided by near-infrared fluorescence imaging.

[0087] The use can comprise the following steps: administering the above imaging agent, providing near-infrared excitation light irradiation to the lesion area, using a signal acquisition and display module to acquire and display signals, and distinguishing and / or stripping the high response area according to the acquired signals.

[0088] The application can further comprise the steps of: preparing the imaging agent based on the basic information of the target lesion area, the basic information including: lesion site, patient age, gender, blood vessel status, blood information, blood supply status of the target area; administering the imaging agent, after the fluorescent imaging agent completes targeted adsorption, providing near-infrared excitation light irradiation to the lesion area, using a signal acquisition and display module to acquire and display signals, and distinguishing and / or stripping the high response area.

[0089] In the application, the imaging agent can be stored at -25℃-15℃.

[0090] In the application, the imaging agent can be a liquid preparation (such as an injection).

[0091] In the application, the imaging agent can be administered by injection (such as intravenous injection).

[0092] In the application, the administration dose of the imaging agent is conventional in the art, for example, according to the administration object mass, the dosage is 0.005-1.5 mg / kg, for example, 0.025 or 0.05 mg / kg, based on the mass of the compound of formula I or its pharmaceutically acceptable salt per unit mass of the administration object.

[0093] The lens distance of the near-infrared fluorescence capture system from the tumor site is conventional in the art, which can be selected as needed, for example, 1-10 cm.

[0094] The near-infrared fluorescence capture system can be used for fluorescence-guided surgery or fluorescence-guided tumor resection of primary tumors, metastatic tumors, lymph nodes, synchronous lesions, or tumor margins. The tumor is, for example, lung cancer, breast cancer (such as TNBC), ovarian cancer, endometrial cancer, or mesothelioma.

[0095] The application provides an application of the compound of formula I or a pharmaceutically acceptable salt thereof, the application comprising:

[0096] (i) used as an imaging agent for cells of a tissue expressing folate receptors;

[0097] (ii) used for preparing an imaging agent for cells of a tissue expressing folate receptors;

[0098] (iii) used for preparing an imaging agent for tumors;

[0099] wherein R is as described in any of the schemes of the application.

[0100] In the application, the imaging agent can comprise (1) a compound of formula I or a pharmaceutically acceptable salt thereof, and (2) a pharmaceutical excipient.

[0101] In the application, the folate receptor expressing tissue cells can be cancer tissue, including parenchymal tissue, interstitial tissue or marginal tissue, such as lung cancer, breast cancer (e.g. TNBC), ovarian cancer, endometrial cancer or mesothelioma.

[0102] In the application, the tumor is, for example, lung cancer, breast cancer (e.g. TNBC), ovarian cancer, endometrial cancer or mesothelioma.

[0103] In the application, the imaging agent can be a near-infrared fluorescent imaging agent, and the wavelength of the near-infrared light is 776-805 nm.

[0104] In the application, the compound of formula I or a pharmaceutically acceptable salt thereof is administered at a dose that is conventional in the art, for example, the compound of formula I or a pharmaceutically acceptable salt thereof is administered in a ratio of 0.005-1.5 mg / kg, for example 0.025 mg / kg or 0.05 mg / kg, to the mass of the subject to be administered.

[0105] In the application, the imaging agent is administered in a manner that is conventional in the art, preferably by injection.

[0106] In the application, the imaging agent is in a dosage form that is conventional in the art, for example, a liquid preparation, preferably an injection.

[0107] In one aspect, the pharmaceutical adjuvant is selected from one or more of a pharmaceutically acceptable carrier, a diluent, a pH adjuster, a pH buffer, an osmotic pressure adjuster, a co-solvent, a metal ion chelator and an antioxidant, for example, comprising water for injection, an osmotic pressure adjuster, for example NaCl, a pH adjuster and / or buffer, for example potassium / sodium dihydrogen phosphate and dipotassium / sodium hydrogen phosphate, citric acid and citrate, the pH adjuster being, for example, hydrochloric acid and / or sodium hydroxide, the metal ion chelator being, for example, EDTA-2Na, and the antioxidant being, for example, sodium sulfite.

[0108] The present application provides an imaging agent comprising a pharmaceutical adjuvant and a compound of formula I or a pharmaceutically acceptable salt thereof as described above;

[0109] wherein R is as described in any aspect of the present application.

[0110] In one aspect, the imaging agent is a liquid preparation, for example, an injection.

[0111] In one aspect, the imaging agent is administered in a manner that is conventional in the art, preferably by injection.

[0112] In some embodiments, the imaging agent is administered at a dose that is conventional in the art, and can be selected as appropriate based on the actual needs, for example, based on the mass of the subject to which it is administered, and the ratio of the compound of Formula (I) or a pharmaceutically acceptable salt thereof to the mass of the subject to which it is administered can be 0.005-1.5 mg / kg, for example, 0.025 mg / kg or 0.05 mg / kg.

[0113] In some embodiments, the pharmaceutical excipients are selected from one or more of pharmaceutically acceptable carriers, diluents, pH adjusters, pH buffers, osmolality adjusters, co-solvents, metal ion chelators, and antioxidants, for example, comprising water for injection, osmolality adjusters such as NaCl, pH adjusters and / or buffers such as potassium / sodium dihydrogen phosphate and di-potassium / sodium hydrogen phosphate, citric acid and citrate salts; pH adjusters such as hydrochloric acid and / or sodium hydroxide; metal ion chelators such as EDTA-2Na; antioxidants such as sodium sulfite.

[0114] In some embodiments, the imaging agent is a near-infrared fluorescence imaging agent, for example, an imaging agent for imaging folate receptor-expressing tissue cells and / or cancer tissue, which can be cancer tissue. The cancer tissue can be lung cancer, breast cancer (e.g., TNBC), ovarian cancer, endometrial cancer, or mesothelioma.

[0115] Terminology:

[0116] The term “pharmaceutically acceptable” means relatively non-toxic, safe, and suitable for use with humans and other mammals.

[0117] The term “pharmaceutically acceptable salt” refers to a salt of a compound with a pharmaceutically acceptable acid or base. When a compound contains relatively basic functionalities, acid addition salts can be obtained by contacting the compound in a suitable inert solvent with a sufficient amount of the pharmaceutically acceptable acid. See, e.g., Handbook of Pharmaceutical Salts: Properties, Selection, and Use (P. Heinrich Stahl, Camille G. Wermuth, 2011, 2nd Revised Edition).

[0118] The term “pharmaceutical excipient” refers to excipients and additional agents used in the production of pharmaceuticals and the dispensing of prescriptions, and all substances contained in a pharmaceutical preparation other than the active ingredient. See, e.g., the People’s Republic of China Pharmacopoeia (2020 Edition) or Handbook of Pharmaceutical Excipients (Raymond C. Rowe, 2009).

[0119] The above-mentioned preferred conditions can be combined arbitrarily to obtain preferred examples of the present application without departing from the common knowledge in the art.

[0120] The reagents and raw materials used in the present application are commercially available.

[0121] The positive progress effect of the present application is that the composition provided by the present application has one or more of the following advantages:

[0122] (1) Good targeting, which helps to mark diseased tissues and identify small lesions and occult lesions;

[0123] (2) Overcoming the shortcoming of fast clearance in cancer tissues, the half-life of ICG is generally 3-4 min, and the short half-life leads to multiple perfusions during surgery, which seriously affects the quality of surgery and prolongs the operation time, and the fluorescence of the compound of the present application can still be detected 24 hours after intravenous injection;

[0124] (3) Improving the fluorescence quantum yield. The fluorescence quantum yield of ICG is usually between 0.01 and 0.1. Due to the low fluorescence quantum yield of ICG, a higher dose is required to maintain effective fluorescence intensity. The compound of the present application is expected to provide effective tumor background ratio (TBR) at 0.005 mg / kg in clinical.

[0125] (4) Compared with OTL38, the compound of the present application has more excellent pharmacokinetic properties, faster elimination speed in blood in vivo, lower background, higher tumor background ratio (TBR), and can more clearly distinguish tumors and normal tissues.

[0126] (5) According to the animal performance of the compound of the present application and OTL38 at the same dose (the tumor background ratio is better than OTL38 at each dose), therefore, the compound of the present application is expected to provide the same or even better lesion tissue differentiation ability than OTL38 in clinical at a lower dose.

[0127] (6) Novel structure, good solubility, small steric hindrance, long-term enrichment of diseased tissues at low concentration, dynamic enrichment and elimination of diseased tissues and elimination of background, and prominent diseased tissues. BRIEF DESCRIPTION OF DRAWINGS

[0128] Figure 1 is a near-infrared imaging diagram of compound 1 administered at 1 nmol per mouse for 1 hour.

[0129] Figure 2 is a near-infrared imaging diagram of OTL38 administered at 1 nmol per mouse for 1 hour.

[0130] Figure 3 is a near-infrared imaging diagram of compound 1 administered at 1 nmol per mouse for 2 hours.

[0131] Figure 4 is a near infrared image of OTL38 administered at 1 nmole per mouse for 2 hours.

[0132] Figure 5 is a near infrared image of Compound 1 administered at 1 nmole per mouse for 4 hours.

[0133] Figure 6 is a near infrared image of OTL38 administered at 1 nmole per mouse for 4 hours.

[0134] Figure 7 is a near infrared image of Compound 1 administered at 1 nmole per mouse for 8 hours.

[0135] Figure 8 is a near infrared image of OTL38 administered at 1 nmole per mouse for 8 hours.

[0136] Figure 9 is a near infrared image of Compound 1 administered at 1 nmole per mouse for 24 hours.

[0137] Figure 10 is a near infrared image of OTL38 administered at 1 nmole per mouse for 24 hours.

[0138] Figure 11 is a near infrared image of Compound 1 administered at 10 nmole per mouse for 1 hour.

[0139] Figure 12 is a near infrared image of OTL38 administered at 10 nmole per mouse for 1 hour.

[0140] Figure 13 is a near infrared image of Compound 1 administered at 10 nmole per mouse for 2 hours.

[0141] Figure 14 is a near infrared image of OTL38 administered at 10 nmole per mouse for 2 hours.

[0142] Figure 15 is a near infrared image of Compound 1 administered at 10 nmole per mouse for 4 hours.

[0143] Figure 16 is a near infrared image of OTL38 administered at 10 nmole per mouse for 4 hours.

[0144] Figure 17 is a near infrared image of Compound 1 administered at 10 nmole per mouse for 8 hours.

[0145] Figure 18 is a near infrared image of OTL38 administered at 10 nmole per mouse for 8 hours.

[0146] Figure 19 is a near infrared image of Compound 1 administered at 10 nmole per mouse for 24 hours.

[0147] Figure 20 is a near infrared image of OTL38 administered at 10 nmole per mouse for 24 hours.

[0148] Figure 21 is a near infrared image of a blank control group of mice.

[0149] Figure 22 shows near-infrared imaging of mouse organs after administration of compound 1 at 1 nmol / mouse.

[0150] Figure 23 shows near-infrared imaging of mouse organs after administration of compound 1 at 10 nmol / mouse.

[0151] Figure 24 shows near-infrared imaging of mouse organs after administration of OTL38 at 1 nmol / mouse.

[0152] Figure 25 shows near-infrared imaging of mouse organs after administration of OTL38 at 10 nmol / mouse. Detailed Implementation

[0153] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0154] Including but not limited to the following embodiments: This refers to the carrier resin itself, which does not participate in the reaction. eq indicates molar multiple. "V" represents the volume / mass ratio; 7V means that 1g of chlorinated resin corresponds to 7mL of reagent.

[0155] Example 1 Compound 1

[0156] Here M is Na + For example, and for Li + K + The same logic applies to situations like these.

[0157] Synthetic route

[0158] Step 1: B01 Synthesis

[0159] Weigh 600 mg of pteroic acid and 643 mg of Fmoc-ethylenediamine hydrochloride, add them to a 250 mL single-necked flask, and dissolve them in 24 mL of DMSO. Add 1.04 g of HTAU and 746 mg of DIEA, stir for 2 h, and after the reaction is complete, add the reaction solution to MTBE, centrifuge, and dry to obtain BO1 (1.1 g, yield 99%). LCMS: [M+H] + =577.2, 2.78 min.

[0160] Step 2: B02 Synthesis

[0161] Weigh B01 (1.0 g) into a 50 mL single-neck flask, dissolve in DMSO (20 mL); add DBU (268 mg), stir for 1 h, and then add the reaction solution to MTBE, centrifuge, and dry to obtain B02 (754 mg of crude product, calculated at a yield of 100%).

[0162] Step 3: Synthesis of B03

[0163] Weigh H-Tyr(tBu)-OtBu.HCl (490 mg) into a 50 mL single-neck flask, dissolve in DMSO (20 mL); add DMAP (7.2 mg) and DCM (10 mL), and then cool to 0-5°C under nitrogen protection; add CDI (485 mg), monitor the reaction end by HPLC, add 5 mL of water, warm to 25°C, stir for 1 h, and then separate the DCM layer and concentrate; weigh B02 (628 mg) and TEA (376 mg) into a 50 mL single-neck flask, dissolve in DMSO (10 mL), add the above-mentioned intermediate obtained after concentration at 0-5°C, and then stir overnight at 25°C; add the reaction solution dropwise to MTBE, centrifuge, and dry to obtain B03 (809 mg, a yield of about 85%).

[0164] LCMS: [M+H] + = 674.4, 2.92 min.

[0165] Step 4: Synthesis of B04

[0166] Weigh B03 (809 mg) into a 50 mL single-neck flask, add 10 mL (90% TFA, 5% water, and 5% triethylsilane), and then stir at 25°C; monitor the reaction end by HPLC, and then prepare the reaction solution to obtain B04 (403 mg, a yield of about 60%). LCMS: [M+H] + = 562.3, 1.42 min.

[0167] Purification of preparation of B04

[0168] Step 5: Synthesis of Compound 1

[0169] Weigh B04 (100 mg, 0.19 mmol) into a 25 mL single-neck flask, configure a sodium carbonate aqueous solution (sodium carbonate: 134 mg, 1.26 mmol, and purified water: 4 mL) into the reaction flask, add int1 (237 mg, 0.27 mmol), and then warm to 70 ～ 75°C, and maintain the temperature for one hour.

[0170] Post-treatment: cool to 20 ～25 °C, preparation, lyophilization to get 50 mg blue solid compound 1, yield 19%, purity 96.30%, MS: [M-4Na+4H+2H] 2+ = 707.3,

[0171] 1 H NMR (400 MHz, DMSO-d6 / D2O) δ 8.63 (s, 1H), 8.06 (s, 2H), 7.78 (d, J = 14.0 Hz, 4H), 7.65 - 7.58 (m, 8H), 7.31 (d, J = 8.4 Hz, 3H), 7.18 (d, J = 8.5 Hz, 3H), 7.00 (d, J = 8.5 Hz, 3H), 6.91 (t, J = 6.1 Hz, 1H), 6.61 (d, J = 8.7 Hz, 2H), 6.28 (s, 1H), 6.19 (d, J = 14.2 Hz, 2H), 6.01 (d, J = 7.0 Hz, 1H), 4.46 (d, J = 5.9 Hz, 2H), 4.25 - 4.04 (m, 6H), 3.16 - 2.90 (m, 8H), 2.78 (dd, J = 13.5, 7.3 Hz, 1H), 2.69 (s, 4H), 1.90 (s, 3H), 1.74 (d, J = 9.1 Hz, 10H), 1.26 (s, 6H), 1.23 (s, 2H), 1.22 (s, 6H).

[0172] Preparation of compound 1

[0173] Similarly, using different raw materials such as replacing the "Fmoc-ethylenediamine hydrochloride" in step 1 of Example 1 with "Fmoc-propylenediamine hydrochloride", "Fmoc-butylenediamine hydrochloride", "Fmoc-pentylenediamine hydrochloride", i.e. compounds 6, 7 and 8 can be obtained by the method of the present example, the specific process is referred to the above, here will not be repeated.

[0174] Example 2

[0175] Preparation of compound 2

[0176] Here M is Na + , for example, and Li + , K + and the like can be similarly realized.

[0177] Synthetic route step 1: C03 solid phase synthesis Note: eq is the molar amount of chloromethylated resin, V is the volume / mass ratio (mL / g), for example 7V means that the amount of reagent is 7 mL for 1 g of chloromethylated resin.

[0178] Step 2: Synthesis of compound 2

[0179] C03 (100 mg, 0.156 mmol) was weighed into a 25 ml single neck flask, a sodium carbonate aqueous solution (sodium carbonate: 100 mg, 0.946 mmol, purified water: 4 ml) was added to the reaction flask, int1 (152 mg, 0.156 mmol) was added, and the temperature was raised to 70 ～ 75°C, and the temperature was maintained for one hour.

[0180] Work-up: the temperature was lowered to 20 ～ 25°C, and 84 mg of blue solid compound 2 was obtained by preparation and lyophilization, with a yield of 23%, purity 97.65%, MS: [M-4Na+4H+2H] 2+ 743.9,

[0181] 1 H NMR (400 MHz, DMSO-d6 / D2O) δ 8.60 (s, 1H), 7.77 (d, J = 13.8 Hz, 2H), 7.59 (dd, J = 18.6, 7.8 Hz, 6H), 7.28 (d, J = 8.8 Hz, 2H), 7.18 (d, J = 8.4 Hz, 2H), 6.97 (d, J = 8.4 Hz, 2H), 6.59 (d, J = 8.7 Hz, 2H), 6.14 (d, J = 14.2 Hz, 2H), 4.45 (s, 2H), 4.18 (s, 2H), 4.05 (s, 5H), 3.54 - 3.38 (m, 6H), 3.38 - 3.33 (m, 2H), 3.30 (d, J = 5.3 Hz, 2H), 2.95 (s, 1H), 2.77 (s, 1H), 2.64 (s, 4H), 2.56 (t, J = 6.7 Hz, 4H), 2.20 (d, J = 5.8 Hz, 2H), 1.86 (s, 2H), 1.74 (d, J = 19.5 Hz, 9H), 1.23 (d, J = 2.6 Hz, 12H).

[0182] Purification of compound 2

[0183] Similarly, using different raw materials, such as replacing "Fmoc-PEG2-CH2CH2COOH" in Step 1 of Example 2 with "Fmoc-PEG3-CH2CH2COOH", "Fmoc-PEG4-CH2CH2COOH", "Fmoc-PEG5-CH2CH2COOH", compounds 3, 4 and 5 can be obtained by the method of the present example, and the specific process is referred to the above, which will not be repeated here.

[0184] Example 1 for effect test

[0185] 1. In vivo activity imaging of compound 1 (compared with OTL38, CAS: % 1628858-03-6): lung cancer model

[0186] BALB / c nude (athymic nude mice) was used to construct a HCC827 (human lung cancer cell line ATCC_CRL-2868) lung cancer subcutaneous tumor-bearing mouse model, and when the average tumor volume reached about 300-400 mm 3 , the mice were grouped and administered. The mice in the administration group were divided into 4 groups, 3 mice in each group; 3 mice in the blank control group. The mice bearing HCC827 tumor xenografts were intravenously injected with 1, 10 nmol / mouse of compound 1 and OTL38 (5% glucose solution, the same below), and the blank control group was injected with 5% glucose solution (see Table 1 below), and then whole body imaging study was performed using a small animal live imaging system (IVIS Lumina LT serier III), which contains a near-infrared fluorescence imaging system. Imaging was performed at 1h, 2h, 4h, 8h, 24h (the blank control group was imaged at 1h and 24h), and the same diameter circle was used to take the tumor and background sites, and the fluorescence values were obtained, and the tumor-to-background ratio (TBR) was calculated, and the average value was calculated, the larger the value, the more likely to provide clearer tumor boundaries, and it is expected to provide better surgical field in surgery. The specific results are shown in Figures 1-20 (in the figures, the test data of compound 1, the test data of OTL38 are shown in order, wherein, Radiant Efficiency is the radiant efficiency (p / sec / cm 2 / sr) / (μw / cm 2 ), and Table 2.

[0187] Table 1 In vivo live imaging grouping

[0188] The 4 administration groups had some fluorescence enrichment in the tumor at 1h, and the tumor and non-tumor sites could be roughly distinguished from the image, and the boundary tended to be obvious at the subsequent time points, and continued until the last time point of the experiment, 24h.

[0189] All four dosing groups provided a certain tumor background ratio (TBR) at 1 hour and beyond (except for the OTL38 1 nmol / animal group at 1 hour). In terms of compounds, compound 1 showed superior TBR values ​​at every time point across both doses compared to OTL38. At different dose levels, the compound 1 10 nmol / animal group was superior to the 1 nmol / animal group at every time point. There was no difference in TBR values ​​between the OTL38 1 nmol / animal and 10 nmol / animal groups, and the increased dose did not improve imaging boundary clarity. Compound 1 is expected to provide better tumor background data in subsequent dose optimization studies.

[0190] The results showed that compound 1 combined with the near-infrared fluorescence imaging system could distinguish tumors from background in mice as quickly as 1 hour. The TBR peak values ​​of 1 nmol / mouse and 10 nmol / mouse were at 8 hours and 24 hours, respectively, and its performance in mice was significantly better than that of OTL38.

[0191] Table 2 Comparison of tumor background ratio data for OTL38 and Compound 1 in live imaging

[0192] 2. Imaging of ex vivo tissues – Tissue distribution studies

[0193] A subcutaneous tumor-bearing mouse model of HCC827 (human lung cancer cell line) lung cancer was constructed in BALB / c nude mice (athymic nude mice). The average tumor volume reached approximately 300–400 mm. 3 The mice were divided into four groups of three mice each, and a control group of three mice (grouping was the same as described in the in vivo imaging study). Mice bearing HCC827 tumor xenografts were intravenously injected with 1, 10 nmol / mouse of compound 1, and OTL38 (5% glucose solution, the same below), while the control group was injected with 5% glucose solution. Whole-body imaging was then performed using a small animal in vivo imaging system containing a near-infrared fluorescence imaging system. Imaging was performed at 1h, 2h, 4h, 8h, and 24h (the control group was imaged at 1h and 24h). After 24h in vivo fluorescence imaging, the mice were euthanized, and organs (tumor, heart, liver, spleen, lung, kidney, stomach, muscle, skin, ovary, pancreas, colon, and small intestine) were collected for in vivo imaging system measurements. The results are shown in Figures 21-25. The fluorescence ratios of mouse tumors to muscle tissue, ovarian tissue, and lung tissue were also calculated, as shown in Table 3 below.

[0194] The results showed that at the 24-hour time point, in the 1 nmol / animal group, the fluorescence of compound 1 and OTL38 was not sufficiently observed in the tumor site, but due to the low uptake in other tissues, this dose group showed relatively obvious differentiation in tumor / muscle and tumor / lung (see Table 3 for details); in the 10 nmol / animal group, both compound 1 and OTL38 showed obvious fluorescence in the tumor, and this dose group showed better differentiation in tumor / muscle and tumor / lung than the 1 nmol / animal group (see Table 3 for details), and is expected to be able to distinguish positive resection margins in clinical use.

[0195] Significant fluorescence was observed in the kidneys, which may be related to drug excretion in urine. A small amount of fluorescence was also observed in the healthy lungs, liver, stomach, and ovaries of the 10 nmol group, possibly due to the slight expression of FRα in these tissues. During data processing, since ovarian cancer also overexpresses FRα, the tumor / ovarian ratio was calculated. The 10 nmol / animal groups of both compounds showed significant differences compared to the control group, suggesting the potential application value of these two compounds in ovarian cancer.

[0196] Table 3. Fluorescence ratio of subcutaneous tumor to normal tissue in tumor-bearing mice 24 h after injection of 1, 10 nmol / mouse of compound 1 and OTL38.

[0197] Example 2 of effect test

[0198] In vivo imaging studies

[0199] Subcutaneous tumor-bearing mouse models of lung cancer were constructed in BALB / c nude mice using HCC827 (human lung cancer cell line, Jicui Yaokang) and A549 (folate receptor α-negative cell line, Jicui Yaokang). The average tumor volume reached approximately 300–400 mm. 3 Grouping and administration began at specific times (grouping details are shown in Table 4 below). Mice bearing tumor xenografts were intravenously injected with 0.025 and 0.05 mg / kg of Compound 1, Compound 2, and OTL38 (5% glucose solution, the same below), respectively, while the blank control group was injected with 5% glucose solution. Whole-body imaging studies were then performed using a small animal in vivo imaging system containing a near-infrared fluorescence imaging system. Imaging was performed at 1h, 2h, 4h, 8h, and 24h, using the same diameter to delineate the tumor and background areas, acquiring fluorescence values, and calculating the tumor-to-background ratio. A higher ratio tends to provide a clearer tumor boundary, potentially offering a better surgical field during surgery. Specific results are shown in Table 5 below.

[0200] Table 4 Grouping of in vivo imaging

[0201] At 1 hour, some fluorescence enrichment was observed in the tumor area of ​​all six drug-treated groups, and the tumor and non-tumor areas could be roughly distinguished from the images. The boundary became clearer at subsequent time points and continued until the last time point of the experiment, 24 hours later.

[0202] All six dosing groups provided a certain tumor background ratio (TBR) at 1 hour and beyond. At different dose levels, there were no significant differences in TBR values ​​at each time point between the OTL38, compound 1, and compound 2 0.025 mg / kg and 0.05 mg / kg dose groups. The 0.05 mg / kg dose groups of compound 1 and compound 2 were superior to their lower dose groups, suggesting that: 1) increasing the dose may increase the tumor background ratio of compound 1 and compound 2; 2) the difference between two-fold dose intervals was not significant, and further dose intervals need to be increased to investigate dose-related factors. Compound 1 and compound 2 are expected to provide better tumor background data in subsequent dose optimization studies. At the compound level, compound 1 showed a significant advantage in tumor background ratio, followed by compound 2, while OTL38 had the lowest. This suggests that structural changes in compounds 1 and 2 led to alterations in pharmacokinetic properties. This conclusion is also reflected in the background fluorescence values ​​of the three compounds, as detailed in Table 6: At the same dose level, the background fluorescence values ​​were: OTL38 > compound 1 > compound 2. Part of the background fluorescence originates from blood vessels throughout the tissue, suggesting that the elimination rate in the blood should be: OTL38 < compound 1 < compound 2. Therefore, the superior tumor background ratio of compounds 1 and 2 is likely due to a certain level of tumor accumulation and lower background interference, thus widening the gap with OTL38. Good pharmacokinetic properties are not easily achieved, and finding changes in pharmacokinetic properties due to structural alterations is even more difficult. Compounds eliminated too quickly in the blood generally have poor tissue accumulation due to their short distribution time; while compounds eliminated too slowly in the blood require a longer time to reach a low background, which usually means a longer preoperative waiting time. Furthermore, without higher tumor accumulation, a high background means a low tumor background ratio, resulting in less clear tumor boundaries. How to achieve a balance: that is, a certain rate of blood elimination can result in a lower background while allowing the target tissue to accumulate within a certain time window.

[0203] The compound protected by this patent is a small molecule compound that targets the folate receptor. To confirm its targeting, an in vivo imaging experiment was conducted using the folate receptor-negative cell line A549. All six treatment groups showed no difference from the control group, confirming its receptor specificity. Tumor background ratio data are shown in Table 7 below.

[0204] Table 5 Comparison of tumor background ratio (TBR) data for in vivo imaging of OTL38, compound 1, and compound 2 (HCC827 group)

[0205] Table 6 In vivo imaging OTL38, compound 1 and compound 2 background fluorescence value (unit: [p / s / cm^2 / sr] / [μW / cm^2]) data comparison (HCC827 group)

[0206] Table 7 In vivo imaging OTL38, compound 1 and compound 2 tumor background ratio (TBR) data comparison (A549 group)

[0207] Ex vivo tissue imaging-tissue distribution study

[0208] HCC827 (human lung cancer cell line, ATCC) subcutaneous tumor-bearing mouse model was constructed on BALB / c nude (athymic nude mice), and the average tumor volume reached about 300-400mm 3 When the average tumor volume reached about 300-400mm, the mice bearing HCC827 tumor xenografts were intravenously injected with 0.025mg / kg, 0.05mg / kg of compound 1, compound 2 and OTL38 (5% glucose solution, same below), and the blank control group was injected with 5% glucose solution (grouping was the same as the HCC827 group in the in vivo imaging study). 2h after administration, the whole mice of the 7 groups were euthanized, and the tumor, heart, liver, spleen, lung, kidney, stomach, back muscle, back skin, ovary, pancreas, colon and small intestine were taken out for fluorescence imaging. The fluorescence ratio of the mouse tumor to muscle tissue, ovarian tissue and lung tissue was calculated, as shown in Table 8 below.

[0209] From the data analysis in Table 8, it can be seen that, except for the two dose groups of OTL38, the ratios of compound 1, compound 2 tumor and muscle, healthy lung, ovary are statistically different, indicating that positive tumor tissue and muscle, healthy lung, ovary can produce obvious distinction, and it is expected to distinguish the positive margin in lung cancer and ovarian cancer clinical surgery. The reason for evaluating ovarian cancer here is that folate receptor FRα is overexpressed in most ovarian cancer and lung cancer, and this experiment is a subcutaneous tumor-bearing model constructed by human lung cancer cell line, which overexpresses folate receptor α, and to a certain extent, the tissue ratio of tumor expressing folate receptor to healthy ovary can be guessed its possible application in ovarian cancer.

[0210] The tumor to healthy lung tissue ratio of the two dose groups of OTL38 failed to be distinguished from the blank control group, which might be because of slow elimination in blood, the tumor accumulation at the 2h time point was less than the interference of background, and the expected time point was shifted, which might bring better results. Compared with OTL38, compounds 1 and 2 are expected to meet the surgical requirements in a shorter time after clinical administration, and combined with the in vivo imaging results (tumor to background ratio showing an upward trend, and the peak appearing at 24h), the tumor to tissue distinction at subsequent time points will be clearer. Taking both into account, compounds 1 and 2 are expected to provide a wider surgical time window.

[0211] Table 8 Subcutaneous tumor to normal tissue fluorescence ratio in dissected tissues of tumor-bearing mice injected with 0.025, 0.05 mg / kg of compounds 1, 2, and OTL38 at 2h

[0212] Example 3 (Ovarian Cancer)

[0213] SKOV3 (Shanghai Cell Bank) ovarian cancer subcutaneous tumor-bearing mouse models were constructed on NCG mice, and the average tumor volume reached about 300-400 mm 3 When the average tumor volume reached about 300-400 mm

[0214] Table 9 In vivo imaging grouping

[0215] Except for the 0.025 mg / kg dose group of OTL38, the rest of the five administration groups had some fluorescence enrichment in the tumor part at 1h, and the tumor and non-tumor parts could be roughly distinguished from the image, and the boundary tended to be clear at subsequent time points, which continued until the last time point of 24h of this experiment.

[0216] From different dose levels, the two dose groups of OTL38 could provide a certain tumor to background ratio after 2h, and the remaining four administration groups could provide a certain tumor to background ratio at 1h and thereafter. At different dose levels, the high and low doses of the three compounds had little difference, and the TBR of the high dose group was slightly higher than that of the low dose group, suggesting that increasing the dose later might have greater application value.

[0217] Among different compounds, compound 1 is the most obvious, compound 2 is the second, OTL38 is weaker, but still can distinguish tumor after 2h, and provide clear surgical margin.

[0218] Table 10 Tumor background ratio (TBR) data comparison of SKOV3 tumor-bearing mice injected with 0.025, 0.05 mg / kg of compound 1, compound 2, OTL38

[0219] Although the specific embodiments of the present application are described above, those skilled in the art should understand that these are only illustrative, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present application. Therefore, the protection scope of the present application is defined by the appended claims.

Claims

1. A compound of Formula I: ###0001### or a pharmaceutically acceptable salt thereof. wherein, R is 2. The compound of claim 1, or a pharmaceutically acceptable salt thereof, having the formula I, wherein which satisfies one or more of the following conditions: (1) R is For example (2) a pharmaceutically acceptable salt of the compound of Formula I containing a pharmaceutically acceptable cation, the number of cations can be 1, 2, 3 or 4, and the cation can be K + , Na + , Li + or NH4 + . For example, a pharmaceutically acceptable salt of the compound of Formula I can be a tetrasodium salt of the compound of Formula I. (3) the compound of Formula I or its pharmaceutically acceptable salt is a small molecule compound targeting folate receptor.

3. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein The compound of Formula I is any one of the following compounds: n is 2, 3, 4, or 5 m is 1, 2, 3 or 4 。 4. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein The pharmaceutically acceptable salt of the compound of Formula I is a compound of Formula II; wherein M 1 , M 2 , M 3 , and M 4 are each independently H or a pharmaceutically acceptable cation; R is as defined in claim 1; Preferably, the pharmaceutically acceptable cation is a monovalent cation, for example K + , Na + , or Li + ; Further preferably, the compound of Formula II is n is 2, 3, 4, or 5 m is 1, 2, 3 or 4 。 5. A small molecule compound targeting folate receptor, characterized in that, The structure is: wherein M is a monovalent cation, R is selected from Preferably, the monovalent cation is selected from potassium ion, sodium ion, lithium ion.

6. The small molecule compound targeting folate receptor according to claim 5, wherein The small molecule compound is wherein M is a potassium ion, a sodium ion, a lithium ion.

7. A process for the preparation of a compound of formula I as claimed in any one of claims 1 to 4 or a pharmaceutically acceptable salt thereof or a small molecule compound targeting folate receptor as claimed in claim 5 or 6, wherein, ###00006### I The preparation method comprises the following steps: The first intermediate is prepared in accordance with the following scheme: The first intermediate is reacted with a first compound to obtain the target small molecule compound, and the first compound is wherein M 2 , M 3 , M 4 are each independently H or a pharmaceutically acceptable cation, e.g., a monovalent cation, R is selected from Preferably, the preparation method satisfies one or more of the following conditions: (1) the reaction of the first intermediate and the first compound is carried out in aqueous carbonate, preferably, the carbonate is selected from sodium carbonate, potassium carbonate, lithium carbonate; (2) the reaction condition is 70-75℃, and the reaction time is 1-2h.

8. A compound of Formula V: ###0006### V or a pharmaceutically acceptable salt thereof. wherein R is as defined in any one of claims 1-7; Preferably, said compound of formula V is any one of the following compounds: n is 2, 3, 4, or 5 m is 1, 2, 3 or 4 。 9. A pharmaceutical composition comprising the compound of Formula I or its pharmaceutically acceptable salt according to any one of claims 1-4, the small molecule compound targeting folate receptor according to claim 5 or 6; Preferably, the pharmaceutically acceptable salt of the compound of Formula I is the compound of Formula II according to claim 4.

10. Use of a substance M in the preparation of a medicament for treating or diagnosing cancer tissue, or use of a substance M in a targeting agent targeting cancer tissue, wherein the substance M is the compound of Formula I or its pharmaceutically acceptable salt according to any one of claims 1-4, the small molecule compound targeting folate receptor according to claim 5 or 6, or the pharmaceutical composition according to claim 9; Preferably, the cancer tissue is folate receptor-expressing cancer tissue, which can include parenchymal tissue or interstitial tissue or marginal tissue, such as lung cancer, breast cancer or ovarian cancer.

11. A near-infrared fluorescence capture system, comprising: It comprises an imaging module containing a compound of formula I or a pharmaceutically acceptable salt thereof. wherein, R is 12. The near-infrared fluorescence capture system of claim 11, wherein, which satisfies one or more of the following conditions: (1) the imaging module is used to provide the compound of Formula I or its pharmaceutically acceptable salt to a target lesion area, such as folate receptor-expressing tissue cells and / or cancer tissue; (2) the imaging module comprises an imaging agent, wherein the imaging agent comprises the compound of Formula I or its pharmaceutically acceptable salt and a pharmaceutical adjuvant, such as one or more selected from pharmaceutically acceptable carriers, diluents, pH adjusters, pH buffers, osmotic pressure adjusters, solubilizers, metal ion chelators and antioxidants, for example, comprising water for injection, an osmotic pressure adjuster, a pH adjuster and / or a buffer, wherein the osmotic pressure adjuster is, for example, NaCl, the pH buffer is, for example, potassium / sodium dihydrogen phosphate and dipotassium / sodium hydrogen phosphate, citric acid and citrate, the pH adjuster is, for example, hydrochloric acid and / or sodium hydroxide, the metal ion chelator is, for example, EDTA-2Na, and the antioxidant is, for example, sodium sulfite; (3) the near-infrared fluorescence capture system further comprises a light source module and a signal acquisition and display module; (4) the preparation method of the imaging agent comprises the following steps: mixing and dissolving the pharmaceutical adjuvant and the compound of Formula I or its pharmaceutically acceptable salt, and sterilizing to obtain the imaging agent; (5) R is For example (6) the pharmaceutically acceptable salt of the compound of Formula I contains a pharmaceutically acceptable cation, and the number of cations is 1, 2, 3 or 4. Preferably, the pharmaceutically acceptable salt of the compound of Formula I is a compound of Formula II: wherein M 1 , M 2 , M 3 , and M 4 are each independently H or a pharmaceutically acceptable cation; R is as defined in claim 11.

13. The near-infrared fluorescence capture system of claim 11 or 12, wherein, which satisfies one or more of the following conditions: (1) the signal acquisition and display module comprises a near-infrared visual capture device with a near-infrared camera and a display device, the near-infrared camera is used to acquire the fluorescent signal emitted by the imaging agent, and the display device is used to display the acquired signal; (2) the light source module is used to provide visible light or near-infrared excitation light to the lesion area, and the lesion area is the tissue cells targeted by the imaging agent; (3) the folate receptor-expressing tissue cells are cancer tissues, and the cancer tissues include parenchymal tissues, interstitial tissues, or marginal tissues; (4) the near-infrared fluorescence capture system further comprises a power supply for powering the light source module, the imaging module, and the signal acquisition and display module; (5) the cation is K + , Na + , Li + , or NH4 + .

14. The near-infrared fluorescence capture system of claim 13, wherein, which satisfies one or more of the following conditions: (1) the mirror of the signal acquisition and display module is an optical endoscope or an electronic endoscope; (2) the near-infrared camera is configured to detect visible light or near-infrared light with an absorption and emission maximum between about 400 nm and 900 nm; (3) the wavelength of the near-infrared excitation light is 776-805 nm; (4) the cancer tissues are lung cancer, breast cancer, ovarian cancer, endometrial cancer, or mesothelioma, and the breast cancer is, for example, triple-negative breast cancer; (5) the camera can simultaneously receive visible light and near-infrared light.

15. The near-infrared fluorescence capture system of claim 11 or 12, wherein, The compound of Formula I is any one of the following compounds: n is 2, 3, 4, or 5 m is 1, 2, 3, or 4 ； Alternatively, the compound of Formula II is any one of the following compounds: n is 2, 3, 4, or 5 m is 1, 2, 3, or 4 。 16. Use of the near-infrared fluorescence capture system according to any one of claims 11-15 in near-infrared fluorescence imaging-guided surgery. Preferably, the use satisfies one or more of the following conditions: (1) the use comprises the following steps: administering the imaging agent, providing near-infrared excitation light irradiation to the lesion area, using the signal acquisition and display module to acquire and display the signal, and distinguishing and / or separating the high response area according to the acquired signal; (2) in the use, the imaging agent is stored at -25°C to 15°C; (3) in the use, the imaging agent is a injection; (4) in the use, the imaging agent is administered by injection; (5) in the use, the dose of the imaging agent administered is 0.005-1.5 mg / kg, for example 0.025 or 0.05 mg / kg, based on the mass of the compound of formula I or a pharmaceutically acceptable salt thereof per unit mass of the administration subject; (4) the lens of the near-infrared fluorescence capture system is 1-10 cm away from the tumor site; (5) the near-infrared fluorescence capture system is used for fluorescence-guided surgery or fluorescence-guided tumor resection of primary tumors, metastatic tumors, lymph nodes, synchronous lesions, or tumor margins; the tumor is, for example, lung cancer, breast cancer, ovarian cancer, endometrial cancer, or mesothelioma.

17. Use of a compound of Formula I: ###0006### or a pharmaceutically acceptable salt thereof, as claimed in any one of claims 11-15, comprising: (i) for use as an imaging agent for folate receptor-expressing tissue cells; (ii) for use in the preparation of an imaging agent for folate receptor-expressing tissue cells; (iii) an imaging agent for preparing a tumor; R is as defined in any one of claims 11-15.

18. The use of a compound of Formula I or a pharmaceutically acceptable salt thereof as claimed in claim 17, wherein, which satisfies one or more of the following conditions: (1) in the use, the imaging agent comprises (1) the compound of formula I or a pharmaceutically acceptable salt thereof, and (2) a pharmaceutical excipient; Preferably, the pharmaceutical adjuvant contains one or more selected from pharmaceutically acceptable carriers, diluents, pH adjusters, pH buffers, osmotic pressure adjusters, co-solvents, metal ion chelators and antioxidants, for example, contains water for injection, osmotic pressure adjusters, pH adjusters and / or buffers, the osmotic pressure adjusters such as NaCl, the pH buffers such as potassium / sodium dihydrogen phosphate and dipotassium / sodium hydrogen phosphate, citric acid and citrate; the pH adjusters such as hydrochloric acid and / or sodium hydroxide; the metal ion chelators such as EDTA-2Na; the antioxidants such as sodium sulfite; (2) In the use, the expression folate receptor tissue cells are cancer tissues, the cancer tissues include parenchymal tissue, interstitial tissue or marginal tissue, for example, lung cancer, breast cancer, ovarian cancer, endometrial cancer or mesothelioma, the breast cancer such as triple negative breast cancer; (3) In the use, the tumor is lung cancer, breast cancer, ovarian cancer, endometrial cancer or mesothelioma, the breast cancer such as triple negative breast cancer; (4) In the use, the imaging agent is a near-infrared fluorescent imaging agent, the wavelength of the near-infrared light is 776-805 nm; (5) In the use, the compound of formula I or a pharmaceutically acceptable salt thereof is administered at a dose of 0.005-1.5 mg / kg, for example, 0.025 mg / kg or 0.05 mg / kg, based on the mass of the subject; (6) In the use, the imaging agent is administered by injection; (7) In the use, the imaging agent is in the form of a liquid preparation, for example, an injection.

19. An imaging agent, characterized in that, comprising a pharmaceutically acceptable excipient and a compound of Formula I or a pharmaceutically acceptable salt thereof as described in any one of claims 11-15; R is as defined in any one of claims 11-15.

20. The imaging agent of claim 19, wherein, It satisfies one or more of the following conditions: (1) The imaging agent is administered by injection; (2) The imaging agent is in the form of a liquid preparation, for example, an injection; (3) The imaging agent is administered at a dose of 0.005-1.5 mg / kg, for example, 0.025 mg / kg or 0.05 mg / kg, based on the mass of the subject; (4) The pharmaceutical adjuvant contains one or more selected from pharmaceutically acceptable carriers, diluents, pH adjusters, pH buffers, osmotic pressure adjusters, co-solvents, metal ion chelators and antioxidants, for example, contains water for injection, osmotic pressure adjusters, pH adjusters and / or buffers, the osmotic pressure adjusters such as NaCl, the pH buffers such as potassium / sodium dihydrogen phosphate and dipotassium / sodium hydrogen phosphate, citric acid and citrate; the pH adjusters such as hydrochloric acid and / or sodium hydroxide; the metal ion chelators such as EDTA-2Na; the antioxidants such as sodium sulfite; (5) The imaging agent is a near-infrared fluorescent imaging agent, for example, an imaging agent for expression folate receptor tissue cells and / or cancer tissues, the expression folate receptor tissue cells can be cancer tissues, for example, lung cancer, breast cancer, ovarian cancer, endometrial cancer or mesothelioma, the breast cancer such as triple negative breast cancer.

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