Phosphoramidate-Based PSMA-Targeted Small Molecule Drug Conjugates

Abstract

The present invention relates to small molecules with high affinity and specificity for prostate-specific membrane antigen (PSMA) and methods of using them for therapeutic and diagnostic purposes.

Description

[Technical field]

[0001] Statement of Government Interests This application was supported by Grant No. R21CA223121 awarded by the National Institutes of Health. The United States Government has certain rights in this invention.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS The present invention claims priority from U.S. Provisional Application No. 63 / 305,770, filed February 2, 2022, the disclosures of each of which are incorporated by reference in their entireties herein. [Background technology]

[0003] The present invention relates to small molecules with high affinity and specificity for prostate-specific membrane antigen (PSMA) and methods of using them for therapeutic and diagnostic purposes.

[0004] Overview of related fields Prostate cancer (PCa) is the most diagnosed cancer in American men and is one of the leading causes of cancer-related deaths after lung cancer. In general, patients with localized disease can be treated with radical prostatectomy and / or radiation therapy. Patients with metastatic forms of PCa can be treated palliatively with androgen deprivation strategies, but most patients with metastatic disease experience disease progression that can eventually evolve into metastatic castration-resistant prostate cancer (mCRPC), which has poor survival rates. Chemotherapy (e.g., docetaxel, cabazitaxel) is often given after antiandrogen therapy has failed, but responses are often limited and are associated with on-target and off-target toxicities, especially in older men. Better therapeutic approaches are clearly needed for late-stage PCa patients.

[0005] Prostate-specific membrane antigen (PSMA) is a type II transmembrane protein that is highly overexpressed by the majority of all prostate cancers. PSMA expression is further upregulated in cancer cells from poorly differentiated, metastatic, hormone-refractory cancers, and mCRPC patients. Moreover, PSMA exhibits robust internalization from the cell surface, making it an ideal target for imaging and therapy. Indeed, PSMA-targeted radiopharmaceutical therapy has shown promise in clinical trials, and several radioligand therapies and antibody-drug conjugates (ADCs) have demonstrated efficacy in preclinical studies. Issues related to recurrence, off-target toxicity, immunogenicity of antibody-based therapy, and the stringent requirements imposed on facilities that produce and manage radiopharmaceuticals represent significant challenges for drug development, FDA approval, and use in the oncology community of agents to treat mCRPC.

[0006] Thus, there remains a need for effective therapies that precisely localize to prostate cancer lesions without significant off-target toxicity, but that are associated with lower manufacturing costs and avoid the regulatory challenges associated with producing and handling radiopharmaceuticals. Summary of the Invention

[0007] Small molecule-drug conjugates (SMDCs) represent an attractive alternative to the more conventional ADC approach for PSMA-targeted chemotherapy delivery. Both technologies typically include a PSMA targeting motif (antibody vs. enzyme inhibitor), a spacer, a cleavable linker, and a potent cytotoxic payload. After binding to cell surface PSMA, these agents are expected to internalize and accumulate in endosomes and lysosomes, which typically allow efficient release of the cytotoxic payload in the target cell by enzymatic cleavage. However, compared to anti-PSMA antibodies, small molecule PSMA inhibitors show accurate localization similar to prostate cancer lesions, but their rather low molecular weight and simpler molecular characterization are associated with lower manufacturing costs, flexibility in determining optimal dose regimens, and higher tolerated doses. The toxicity profile of PSMA-SMDCs is expected to be much lower than ADCs, due to their shorter residence time and more rapid and uniform diffusion to the tumor mass compared to normal organs such as the kidney, lacrimal gland, and salivary gland.

[0008] Thus, provided herein are therapeutic and diagnostic agents for prostate cancer that exploit the potency and specific affinity of small molecule inhibitors for PSMA. Thus, in one aspect, the present disclosure provides a compound of formula (I): [ka] or a pharma- ceutically acceptable salt thereof, wherein: D is -NR 2 a therapeutic or diagnostic agent attached to L via an -, -S-, or -O- moiety; L is an acid cleavable linker, X is a bond or [ka] and n is in the range of 1 to 6; R 1 , R 2 , R 3 , and R 4is independently H, -C1-C6 alkyl, or a protecting group, or a pharma- ceutically acceptable salt thereof.

[0009] The present disclosure also provides pharmaceutical compositions comprising the compounds of the present disclosure disclosed herein and a pharma- ceutically acceptable excipient, carrier, adjuvant, stabilizer, and / or diluent.

[0010] One aspect of the present disclosure provides a method for delivering a therapeutic or diagnostic agent to a subject, comprising administering to a subject in need of such an agent a therapeutically effective amount of a compound of the present disclosure disclosed herein, or a pharmaceutical composition of the present disclosure disclosed herein.

[0011] One aspect of the present disclosure provides a method of treating a patient having cancer (e.g., prostate cancer), comprising administering to the patient an effective amount of a compound of the present disclosure disclosed herein, or a pharmaceutical composition of the present disclosure disclosed herein.

[0012] Another aspect of the present disclosure provides a method of imaging one or more cancer cells (such as prostate cancer cells) in a patient, comprising administering to the patient an effective amount of a compound of the present disclosure disclosed herein, or a pharmaceutical composition of the present disclosure disclosed herein.

[0013] In another aspect, the disclosure provides a method for synthesizing a compound of formula (I). Such a method comprises the steps of: [ka] or a pharma- ceutically acceptable salt thereof, Compounds of formula (III): [ka] or a pharma- ceutically acceptable salt thereof, wherein D, L, n, R 1 , R 2 , R3 , and R 4 is as provided above for formula (I).

[0014] Other features and advantages of the present disclosure will become apparent from the following detailed description.

[0015] The accompanying drawings are included to provide a further understanding of the disclosed compositions and methods, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments of the present disclosure, and together with the description, serve to explain the principles and operation of the present disclosure. [Brief description of the drawings]

[0016] [Figure 1] The chemical structures of SMDC1 with a Val-Cit-linker and SMDC2 with a phosphoramidate linker are provided. [Diagram 2] Therapeutic efficacy of SMDC1 and 2. Tumor growth of mice treated with multiple doses of (A) saline, (B) MMAE, (C) CTT1700, SMDC control with non-cleavable phosphoramidate, (D) SMDC1, (E) SMDC2, (F) survival data of mice treated with multiple doses of control and SMDC1 and SMDC2. [Diagram 3] Concentrations of parent drug (filled circles) and MMAE payload (triangles) in plasma (A, B, C) and tumors (D, E, F) are shown following IV administration of 0.8 mg / kg CTT1700 (left column), SMDC1 (middle column), or SMDC2 (right column) to NCr nude mice bearing PC3-PiP tumors. [Figure 4] Representative syntheses of SMDC1 and SMDC2 are provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Before the disclosed processes and materials are described, it is to be understood that the aspects described herein are not limited to particular embodiments, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting, unless specifically defined herein.

[0018] In view of the present disclosure, the methods and compositions described herein can be adapted by one of skill in the art to meet the desired needs. In general, the disclosed compositions and methods take advantage of the potency and specific affinity of small molecule inhibitors of PSMA to provide improvements in the treatment of cancer, particularly prostate cancer.

[0019] Accordingly, one aspect of the disclosure provides compounds having structural formula (I) as described herein.

[0020] In certain embodiments, the present disclosure provides a method for treating a cancer comprising administering to a patient a cancer treatment, comprising administering to said patient a cancer treatment, [ka] The present invention provides a compound,

[0021] Such compounds have the formula: [ka] It can be represented by:

[0022] The present disclosure provides, in certain embodiments, compounds where X is a bond. Such compounds have the formula: [ka] It can be represented by:

[0023] The compounds of the present disclosure described herein include an acid-cleavable linker L (e.g., a linker that degrades in an acidic environment or other desired conditions to release a therapeutic or diagnostic agent). Such linkers, when attached to an agent, can take advantage of the lower intracellular pH (e.g., pH 5.5) or extracellular pH (e.g., pH 6.5) of the target cell type compared to that of blood or normal tissue to trigger a controlled release of the agent.

[0024] In certain embodiments of the present disclosure, the linker L comprises a phosphoramidate group. For example, in certain embodiments, L has the formula: [ka] containing a phosphoramidate of R 1 and R 3 is as provided above with respect to formula (I). In certain embodiments, R 1 is hydrogen, and / or R 3 is hydrogen.

[0025] In certain embodiments of the present disclosure, L is [ka] wherein R 5 is H, -OH, or -OC1-C6 alkyl; R 1 , R 2 , and R 3 is as provided above for formula (I).

[0026] In certain embodiments of the present disclosure, L is [ka] wherein R 5 is H, —OH, or —OC1-C6 alkyl.

[0027] In certain embodiments of the present disclosure, L is [ka] where R 5 is H, —OH, or —OC1-C6 alkyl.

[0028] In certain embodiments of the present disclosure, R 5 is H, -OH, or -OC1-C4 alkyl. In some embodiments, R 5 is H, -OH, or -OC1-C2 alkyl. In some embodiments, R 5 is H, -OH, or -OCH. In some embodiments, R 5 is H or -OCH. In some embodiments, R 5 is H. In some embodiments, R 5 is -OCH3.

[0029] In certain embodiments of the present disclosure, L is [ka] It is.

[0030] The compounds of the disclosure described herein, in certain exemplary embodiments, have the formula: [ka] wherein R 5 is H, -OH, or -OC1-C6 alkyl. In certain embodiments, R 5 is H, -OH, or -OC1-C4 alkyl. In some embodiments, R 5 is H, -OH, or -OC1-C2 alkyl. In some embodiments, R 5 is H, -OH, or -OCH. In some embodiments, R 5 is H or -OCH. In some embodiments, R 5is H. In some embodiments, R 5 is -OCH3.

[0031] In certain embodiments, the compound is 1 , R 2 , and R 3 is of any of the previous embodiments, independently selected from one of the following groups (a)-(o): (a) hydrogen, C1-C6 alkyl, or a protecting group. (b) hydrogen or C1-C6 alkyl. (c) C1-C6 alkyl or a protecting group. (d) C1-C6 alkyl. (e) Hydrogen or a protecting group. (f) Hydrogen. (g) Protecting groups. (h) Any of groups (a) to (d), wherein C1-C6 alkyl is methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, or n-hexyl. (i) Any of groups (a) to (d) in which the C1-C6 alkyl is methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl. (j) Any of groups (a) to (d), wherein the C1-C6 alkyl is methyl, ethyl, n-propyl, or tert-butyl. (k) Any of groups (a) to (d), wherein the C1-C6 alkyl is methyl, ethyl, or tert-butyl. (l) Any of groups (a) to (d) wherein the C1-C6 alkyl is methyl or ethyl. (m) Any of groups (a) to (d) wherein the C1-C6 alkyl is methyl. (n) Any of groups (a) to (d) wherein the C1-C6 alkyl is ethyl. (o) Any of groups (a) to (d) wherein the C1-C6 alkyl is tert-butyl.

[0032] In certain embodiments of the compounds of the present disclosure described herein, R 1 , R 2 , and R 3 is H.

[0033] In certain embodiments, R 1 , R 2 , and R 3 At least one of the following is not H, and the remaining R 1 , R 2 , and R 3 is H.

[0034] In certain embodiments, the compound is 4 Any of the previous embodiments, wherein R is H or methyl. 4 is H.

[0035] In certain embodiments, the present disclosure provides a compound of the formula: [ka] The following exemplary compounds are provided:

[0036] In certain embodiments, the compound is of any of the previous embodiments, where n is in the range of 2 to 4. In certain embodiments, n is 3.

[0037] As provided above, the compounds of formula (I) described herein include a therapeutic or diagnostic moiety, D. Generally, D is -NR 2 D is attached to the linker L via -, -S-, or -O-. It is understood that the drug may actually be a derivative modified at the attachment site. For example, D may be attached to the linker L via -NR 2 It may be modified to include -, -S-, or -O-.

[0038] A therapeutic agent is a molecule useful in the treatment of a disease. Examples of therapeutic agents include chemotherapeutic agents, antibodies, antibody fragments, toxins, enzymes, nucleases such as ribonuclease (RNase) or DNase I, hormones, cytokines, chemokines, angiogenesis inhibitors, antisense oligonucleotides, small interfering RNA (siRNA), chelators, boron compounds, photoactive agents, small molecules, antibiotics, and radioisotopes.

[0039] Chemotherapeutic agents include, for example, anti-cancer agents, anti-neoplastic agents, and cytotoxic agents. Examples of anti-cancer chemotherapeutic agents include, but are not limited to, 5-fluorouracil, bleomycin, busulfan, camptothecin, carboplatin, chlorambucil, cisplatin (CDDP), cyclophosphamide, dactinomycin, daunorubicin, doxorubicin, estrogen receptor binding agents, etoposide (VP16), farnesyl-protein transferase inhibitors, gemcitabine, ifosfamide, mechlorethamine, melphalan, methotrexate, mitomycin, navelbine, nitrosurea, plicamycin, procarbazine, raloxifene, tamoxifen, taxol, temazolomide (aqueous form of DTIC), transplatinum, vinblastine and methotrexate, vincristine, or any of the above analogs or derivatives variants.Chemotherapeutic agents for use against infectious organisms include acyclovir, albendazole, amantadine, amikacin, amoxicillin, amphotericin B, ampicillin, aztreonam, azithromycin, bacitracin, BACTRIM, BATRAFEN, bifonazole, carbenicillin, caspofungin, cefaclor, cefazolin, cephalosporins, cefepime, ceftriaxone, cefotaxime, chloramphenicol, cidofovir, Cipro®, clarithromycin, clavulanic acid, clotrimazole, cloxacillin, doxycycline, econazole, erythrocycline, erythromycin, FLAGYL®, fluconazole, flucytosine, FOSCARNET®, furazolidone, ganciclovir, gefitinib, cephalosporin ... In some embodiments, the antimicrobials include, but are not limited to, cyclosporine, imipenem, isoniazid, itraconazole, kanamycin, ketoconazole, lincomycin, linezolid, meropenem, miconazole, minocycline, naftifine, nalidixic acid, neomycin, netilmicin, nitrofurantoin, nystatin, oseltamivir, oxacillin, paromomycin, penicillin, pentamidine, piperacillin-tazobactam, rifabutin, rifampin, rimantadine, streptomycin, sulfamethoxazole, sulfasalazine, tetracycline, tioconazole, tobramycin, tolcyclate, tolnaftate, trimethoprim-sulfamethoxazole, valacyclovir, vancomycin, zanamir, and zithromycin.

[0040] Hormones can be used as therapeutic agents themselves or in combination with other chemotherapy agents. Progestins such as hydroxyprogesterone caproate, medroxyprogesterone acetate, and megestrol acetate have been used for endometrial and breast cancers. Estrogens such as diethylstilbestrol and ethinyl estradiol have been used for cancers such as prostate cancer. Antiestrogens such as tamoxifen have been used for cancers such as breast cancer. Androgens such as testosterone propionate and fluoxymesterone have also been used to treat breast cancer. Corticosteroid hormones such as prednisone and dexamethasone can improve the effectiveness of other chemotherapy agents. Cytokines used as therapeutic agents include, but are not limited to, lymphokines, monokines, growth factors, and polypeptide hormones. Examples of cytokines include human growth hormone, N-methionyl human growth hormone, bovine growth hormone, parathyroid hormone, thyroxine, insulin, proinsulin, relaxin, prorelaxin, follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), luteinizing hormone (LH), hepatic growth factor, prostaglandins, fibroblast growth factor, prolactin, placental lactogen, OB protein, tumor necrosis factor α, tumor necrosis factor β, Müllerian inhibitory substance, mouse gonadotropin-related peptide, inhibin, activin, vascular endothelial growth factor, integrins, thrombopoietin (TPO), NGF-β, platelet growth factor, TGF-α, TGF-β, insulin-like growth factor ... growth factor I, insulin-like growth factor II, erythropoietin (EPO), bone morphogenetic factor, interferon alpha, interferon beta, interferon gamma, macrophage-CSF (M-CSF), granulocyte-macrophage-CSF (GM-CSF), granulocyte-CSF (G-CSF), IL-1, IL-1 alpha, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12, IL-13, IL-14, IL-15, IL-16, IL-17, IL-18, IL-21, LIF, Kit-ligand, FLT-3, angiostatin, thrombospondin, endostatin, and lymphotoxin.Examples of angiogenesis inhibitors used as therapeutic agents include, but are not limited to, angiostatin, baculostatin, canstatin, maspin, anti-VEGF antibodies, anti-PIGF peptides and antibodies, anti-vascular growth factor antibodies, anti-Flk-1 antibodies, anti-Flt-1 antibodies and peptides, laminin peptides, fibronectin peptides, plasminogen activator inhibitors, tissue metalloproteinase inhibitors, interferon, interleukin-12, IP-10, Gro-β, thrombospondin, 2-methoxyestradiol, proliferin-related tacrolimus, and the like. These include, but are not limited to, proteins, carboxyamidotriazoles, CM101, marimastat, pentosan polysulfate, angiopoietin-2, interferon-alpha, herbimycin A, PNU145156E, 16K prolactin fragment, linomide, thalidomide, pentoxifylline, genistein, TNP-470, endostatin, paclitaxel, accutin, angiostatin, cidofovir, vincristine, bleomycin, AGM-1470, platelet factor 4, and minocycline. Examples of small molecules for use as therapeutic agents include abrin, amantadine, amoxicillin, amphotericin B, ampicillin, aplidine, azaribine, anastrozole, azacitidine, aztreonam, azithromycin, bacitracin, trimethoprim / sulfamethoxazole, batrafen, bifonazole, bleomycin, bortezomib, bryostatin-1, busulfan, calicheamicin, camptothecin, 10-hydroxycamptothecin, carbenicillin, caspofungin, carmustine, cefaclor, ceftriaxone, and the like. Azolines, cephalosporins, cefepime, ceftriaxone, cefotaxime, celecoxib, chlorambucil, chloramphenicol, ciprofloxacin, cisplatin, irinotecan (CPT-11), SN-38, carboplatin, cladribine, cyclophosphamide, cytarabine, dacarbazine, docetaxel, dactinomycin, daunomycin glucuronide, daunorubicin, dexamethasone, diethylstilbestrol, diphtheria toxin, DNase I, doxorubicin, 2-pyrrolinodoxorubicin (2P-DOX),Doxycycline, cyano-morpholinodoxorubicin, doxorubicin glucuronide, duocarmycin (DUBA), epirubicin glucuronide, ethinyl estradiol, 7-ethyl-10-hydroxycamptothecin (SN-38), estramustine, estrogen receptor binding agents, etoposide, etoposide glucuronide, etoposide phosphate, erythrocycline, erythromycin, flagyl, farnesyl-protein transferase inhibitors, floxuridine (FUdR), 3',5'-O-dioleoside Ile-FudR (FUdR-dO), fludarabine, flutamide, fluorouracil, fluoxymesterone, ganciclovir, gentamicin, gelonin, gemcitabine, hydroxyprogesterone caproate, hydroxyurea, idarubicin, ifosfamide, imiquimod, isoniazid, itraconazole, kanamycin, ketoconazole, L-asparaginase, leucovorin, lomustine, mechlorethamine, medroprogesterone acetate, megestrol acetate, melphalan, mercaptopurine, 6-mercaptopurine , methotrexate, mitoxantrone, mithramycin, mitomycin, mitotane, minocycline, naftifine, nalidixic acid, neomycin, navelbine, nitrosurea, nystatin, ranpirnase, oxacillin, paromomycin, penicillin, pentamidine, piperacillin-tazobactam, phenylbutyrate, prednisone, procarbazine, paclitaxel, pentostatin, pokeweed antiviral protein, PSI-341, seco-duocarmycin (seco-DUBA), semustine, rifabutin ... Fabutin, rifampin, rimantadine, streptomycin, sulfamethoxazole, sulfasalazine, streptozocin, tamoxifen, taxane, taxol, testosterone propionate, tetracycline, thalidomide, thioguanine, thiotepa, teniposide, topotecan, transplatinum, trimethoprim-sulfamethoxazole, uracil mustard, valacyclovir, vancomycin, vinblastine, vinorelbine, vincristine, zanamil, zithromycin, and (R)-5-chloro-N, 2 -[4-(4-methylpiperazin-1-yl)phenyl]-N 4-[(tetrahydrofuran-2-yl)methyl]pyrimidine-2,4-diamine ((R)-9b).

[0041] In embodiments, D disclosed herein includes therapeutic agents for the treatment of cancer and non-cancer therapeutic agents. These therapeutic agents include all hydroxyl and amine-containing therapeutic agents for the treatment of cancer, such as molecules that inhibit DNA replication (e.g., doxorubicin, epirubicin, carecheamicin, camptothecin), molecules that stabilize or disrupt microtubules (e.g., paclitaxel, docetaxel, epothilones), Na + / K + These include organic small molecules, including molecules that affect pumps (e.g., strophanthidin), molecules that affect the function of the Golgi apparatus (e.g., norrisolide and active derivatives of norrisolide). These therapeutic agents also include inorganic small molecules, such as all hydroxyl- and amine-containing therapeutic agents for the treatment of cancer, e.g., cisplatin or oxoplatin. Examples of linked antitumor agents include, e.g., CO-doxorubicin and CO-strophanthidin.

[0042] In other embodiments, the D disclosed herein can be any of a variety of proteins of human and non-human origin, such as antibodies (e.g., trastuzumab), hormones (e.g., luteinizing hormone, follicle stimulating hormone), cytokines (e.g., IL-6), growth factors (e.g., G-CSF), bacterial or plant toxins (e.g., Pseudomanas toxin, gelonin, ricin, abrin), and tumor-targeting soluble proteins of any kind; peptides, including engineered and natural peptides, that are toxic to tumor cells, alter the structure or function of such cells, or target other molecules to tumor cells or cells within tumor cells that serve to support tumor cells, such as lysine, TAT-related proteins that enhance cell penetration; and nucleic acids, such as RNA. These include, but are not limited to, antisense RNA, silencing RNA, toxins aptamers, DNA, e.g., naturally occurring and synthetic oligonucleotides, as well as higher molecular weight structures, e.g., plasmids and viral vectors expressing RNA or proteins that are toxic to tumor cells; particles, such as polymer-, protein-, metal-, and inorganic-based particles of any size, e.g., nanoparticles loaded with therapeutic agents, detectable labels such as fluorescent dyes or radionuclides, or imaging agents; proteins, including small molecules, both inorganic and organic small molecules that target cell surface receptors or otherwise bind to the surface or other accessible intra- or extracellular components of tumor cells.

[0043] Therapeutic agents also include drugs that are active in the CNS, such as L-Dopa, Ritalin, Cymbalta, Namenda, and Gleevec.

[0044] In other embodiments, D is an anti-cancer agent, an anti-neoplastic agent, or a cytotoxic molecule. In one embodiment, D is an anti-neoplastic agent, e.g., selected from the group consisting of monomethyl auristatin E (MMAE), monomethyl auristatin F (MMAF), and doxorubicin containing amine groups.

[0045] In one embodiment, D is selected from MMAE, MMAF, doxorubicin, cabazitaxel, docetaxel, paclitaxel, gemcitabine, imiquimod, SN-38, DUBA, seco-DUBA, (R)-9b, and gemcitabine.

[0046] A diagnostic agent is a molecule that can be used in imaging studies such as magnetic resonance imaging (MRI), magnetic resonance tomography (MRT), positron emission tomography (PET), computed tomography (CT), single photon emission computed tomography (SPECT), and optical images such as X-rays. A diagnostic agent is a detectable or traceable label. Examples of diagnostic agents used in these studies include, but are not limited to, radioisotopes, dyes (including those that use biotin-streptavidin complexes), enzymes, contrast agents, fluorescent compounds or molecules, such as fluorescent dyes, paramagnetic ions (for MRI), and small molecules, including both inorganic and organic small molecules, that target cell surface receptors or otherwise bind to the surface or other accessible intra- or extracellular components of tumor cells.

[0047] In certain embodiments, D is a radioisotope, an imaging agent, a fluorescent dye, a near-IR dye, an enzyme, a chemiluminescent agent, a bioluminescent agent, a paramagnetic ion, an ultrasound label, or a radioacoustic label.

[0048] In one aspect, the present disclosure also provides a pharmaceutical composition comprising the compound of the present disclosure described herein and a pharma- ceutically acceptable excipient, carrier, adjuvant, stabilizer, and / or diluent. The pharma- ceutical acceptable excipient, carrier, adjuvant, stabilizer, diluent, etc. included are determined by the composition to be administered and the method of administering the composition. There are a wide variety of suitable formulations of pharmaceutical compositions, including optional pharma- ceutical acceptable carriers, excipients, stabilizers, etc. Acceptable carriers or diluents for therapeutic use are well known in the pharmaceutical arts and are described, for example, in Remington's Pharmaceutical Sciences, 18th Ed., Mack Publishing Co., Easton, Pa. (1990).

[0049] Compositions suitable for parenteral administration, such as by intra-articular (intra-articular), intravenous, intramuscular, intradermal, intraperitoneal, and subcutaneous routes, include aqueous and non-aqueous isotonic sterile injection solutions, which may contain antioxidants, buffers, bacteriostats, and solutes that render the formulation isotonic with the blood of the intended recipient, and aqueous and non-aqueous sterile suspensions, which may include suspending agents, solubilizing agents, thickening agents, stabilizers, and preservatives. Compositions may be administered, for example, by intravenous infusion, orally, topically, intraperitoneally, intravesically, or intrathecally.

[0050] The pharmaceutical compositions disclosed herein may be manufactured by conventional mixing, dissolving, granulating, dragee-making, wet-milling, emulsifying, encapsulating, entrapping, or tabletting processes.The pharmaceutical compositions may be prepared as liquid solutions or suspensions, solid forms suitable for solution or suspension in liquid prior to use, or as emulsions.

[0051] In certain embodiments, the present disclosure also provides the method of using the disclosed compounds for therapeutic and diagnostic purposes.For example, the present disclosure provides a method of treating or ameliorating a disease or condition, which may comprise administering an effective amount of one or more of the compounds described herein or one or more of the pharmaceutical compositions described herein to a subject in need thereof.

[0052] In embodiments, the compounds of the present disclosure deliver anti-cancer drugs to selected tissues. The cancer may be lung cancer, breast cancer, colon cancer, ovarian cancer, prostate cancer, and melanoma.

[0053] Thus, in certain embodiments, the present disclosure provides a method of treating a patient with prostate cancer by administering to the patient an effective amount of a compound described herein or a pharmaceutical composition described herein. The amount of compound and regimen can be routinely determined using art-recognized techniques.

[0054] In certain embodiments, the present disclosure provides a method for imaging one or more cancer cells (such as prostate cancer cells) in a patient by administering to the patient an effective amount of a compound described herein or a pharmaceutical composition described herein. The method may further include imaging the compound in vivo. The imaging may be performed by any imaging technique known in the art.

[0055] definition As used herein, the term "cell" is meant to refer to a cell that is in vitro, ex vivo, or in vivo. In some embodiments, an ex vivo cell may be part of a tissue sample excised from an organism, such as a mammal. In some embodiments, an in vitro cell may be a cell in cell culture. In some embodiments, an in vivo cell is a cell that lives within an organism, such as a mammal.

[0056] As used herein, the term "contacting" refers to bringing together the indicated moieties in an in vitro system or in an in vivo system. For example, "contacting" PSMA with a compound includes administering a compound described herein to a subject or patient, such as a human, as well as introducing a compound into a sample that contains, for example, a cell preparation or purified preparation that contains PSMA.

[0057] As used herein, the terms "subject" or "patient", used interchangeably, refer to any animal, including a mammal, preferably a mouse, rat, other rodent, rabbit, dog, cat, pig, cow, sheep, horse, or primate, and most preferably a human.

[0058] As used herein, the phrase "pharmaceutically acceptable salts" refers to both pharmaceutically acceptable acid and base addition salts and solvates. Such pharmaceutically acceptable salts include those of hydrochloric acid, phosphoric acid, hydrobromic acid, sulfuric acid, sulfinic acid, formic acid, toluenesulfonic acid, methanesulfonic acid, nitric acid, benzoic acid, citric acid, tartaric acid, maleic acid, hydroiodic acid, alkanoic acid such as acetic acid, HOOC-(CH2) where n is 0-4,n -COOH and the like. Non-toxic pharmaceutical base addition salts include salts of bases such as sodium, potassium, calcium, ammonium, and the like. In certain embodiments, the pharma- ceutically acceptable salt is a sodium salt. Those skilled in the art will recognize a wide variety of non-toxic pharma- ceutically acceptable addition salts.

[0059] As used herein, the term "alkyl" refers to a straight or branched chain hydrocarbon containing 1 to 10 carbon atoms, unless otherwise specified. Representative examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl, and n-decyl. When an "alkyl" group is a linking group between two other moieties, it may be straight or branched, and examples include, but are not limited to, -CH2-, -CH2CH2-, -CH2CH2CHC(CH3)-, -CH2CH(CH2CH3)CH2-.

[0060] As used herein, "protecting groups" include, but are not limited to, optionally substituted benzyl, t-butyl ester, allyl ester, alkyl ester (e.g., methyl, ethyl), fluorenylmethoxycarbonyl group (Fmoc), and amino, carboxylic acid and phosphate protecting groups described in Greene's Protective Groups in Organic Synthesis, 4th Edition, which is incorporated by reference. In some embodiments, R 1 is a carboxylic acid protecting group (e.g., methyl or t-butyl ester). In some embodiments, R 2is a nitrogen protecting group (e.g., Boc or benzyl). Optionally, the benzyl group includes, but is not limited to, unsubstituted benzyl, triphenylmethyl (trityl), diphenylmethyl, o-nitrobenzyl, 2,4,6-trimethylbenzyl, p-bromobenzyl, p-nitrobenzyl, p-methoxybenzyl (PMB), 2,6-dimethoxybenzyl, 4-(methylsulfinyl)benzyl, 4-sulfobenzyl, 4-azidomethoxybenzyl, and piperonyl, as well as the benzyl protecting groups for carboxylic acids and phosphoric acids disclosed in Greene's Protective Groups in Organic Synthesis, the relevant portions of which are incorporated by reference. EXAMPLES

[0061] The compounds disclosed herein can be made using procedures well known to those skilled in the art and described herein. For example, compounds of structural formula (I) can be prepared according to the general procedures (below) and / or similar synthetic procedures. Those skilled in the art can adapt the reaction sequences of Examples 1 and 2, as well as the general procedures to suit the desired target molecule. Of course, in certain circumstances, those skilled in the art will use different reagents to affect one or more of the individual steps, or use certain protected versions of the substituents. In addition, those skilled in the art will recognize that the compounds of the present disclosure can be fully synthesized using different routes.

[0062] The compounds and methods of the present disclosure are further exemplified by the following examples, which are not to be construed as limiting the disclosure in scope or spirit to the specific procedures and compounds described therein.

[0063] Development of SMDC1 and SMDC2 Two PSMA-targeted small molecule-drug conjugates, SMDC1 and SMDC2, in Figure 1, were prepared. Compound 1 utilized a valine-citrulline (Val-Cit) dipeptide linker. This linker is cleavable by the lysosome-abundant cathepsin B protease to release the cytotoxic payload. Compound 2 used an acid-labile phosphoramidate linker. This linker exhibits stability at the neutral pH of plasma and rapid release of the payload in the acidic conditions of the endosomal and lysosomal compartments. Monomethyl auristatin E (MMAE), an antitubulin agent that kills cells at sub-nanomolar concentrations by inhibiting the assembly of microtubules and subsequently inducing mitotic arrest, was used as the cytotoxic payload for both SMDCs. In both SMDCs, the phosphoramidate-based inhibitor CTT1298 was selected as the PSMA-targeting molecule due to its documented high affinity, irreversible binding to PSMA (IC 50 =19 nM) and high selectivity for PSMA-expressing cancer cells. Upon binding to extracellular PSMA, CTT1298 derivatized with radiolabeled pendant groups has been shown to undergo rapid and extensive internalization in tumor cells expressing PSMA. Furthermore, conjugation of chemical moieties to CTT1298 does not decrease the binding affinity of this ligand to PSMA.

[0064] With regard to the delivery of therapeutic payloads, one of the major challenges of small molecule PSMA inhibitors is their rapid renal clearance. This is due to the small molecular weight and highly charged (poly-carboxylate) nature of the inhibitor structure, which is also necessary for their high affinity to PSMA. To overcome this pharmacokinetic challenge, the two SMDCs contain an albumin-binding motif that is known to reduce receptor-mediated renal uptake and increase tumor uptake of drug-conjugates.

[0065] The synthesis of SMDC1 and SMDC2 was accomplished via copper-free click reactions (see Figure 4), as provided in more detail below. One key precursor was compound 3, which contains a distorted dibenzocyclooctyne for click chemistry, CTT1298 as a targeting molecule, and an albumin binding moiety into its molecular structure. Azides 4 and 5 incorporated a Val-Cit linker and a phosphoramidate linker, respectively, in addition to the cytotoxic payload. These click chemistry reactions were monitored by HPLC and found to be complete in less than 30 minutes. SMDC1 and SMDC2 were purified by preparative C18-HPLC and further desalted to give isolated yields of 30% and 49%, respectively, and were characterized by HRMS, HPLC, and HPLC. 31 It was fully characterized by P NMR. Example 1. Preparation and characterization of SMDC1 [ka] [ka]

[0066] All anhydrous solvents used in reactions were obtained from commercial sources or were freshly distilled over calcium hydride. 1 H, 13 C, and 31 P NMR spectra were recorded on a Varian 400, a Brucker Avance Neo 500, or a Varian 600 MHz spectrometer. 1 H NMR chemical shifts are relative to CDCl3 (δ=7.26 ppm), CD3OD (δ=3.31 ppm), or D2O (δ=4.79 ppm). 13 C NMR chemical shifts were relative to CDCl3 (δ = 77.23 ppm) or CD3OD (δ = 49.15 ppm). High-resolution mass spectrometry (HRMS) spectra were obtained on an Applied Biosystems 4800 MALDI-TOF / TOF mass spectrometer (Applied Biosystems, Foster City, CA).

[0067] Methyl N2-((S)-5-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-5-oxopentanoyl)-N6-(4-(4-iodophenyl)butanoyl)-D-lysinate (8). A solution of acid, 7 (2 g, 6.59 mmol), and HBTU (2.5 g, 6.59 mmol) was stirred in anhydrous DMF (11 mL) at room temperature for 30 min under Ar. A solution of 6 (2.6 g, 7.91 mmol) and anhydrous Et3N (2.5 mL, 16.5 mmol) in DMF (11 mL) was added to the reaction solution and the reaction was stirred under Ar for 3 h. The reaction was diluted with EtOAc (150 mL) and washed sequentially with 1N HCl (75 mL, 3x), saturated NaHCO3(aq) (75 mL, 2x), and brine (75 mL, 1x). The organic layer was dried over Na2SO4, the volatiles were removed under reduced pressure, and the resulting residue was dried under high vacuum and carried on to the next step without further purification. The isolated yield was 93%. 1 H NMR(400MHz,DMSO-d6)δ 8.14(d,J=7.7Hz,1H),7.40-7.28(m,5H),7.23(t,J=5.7Hz,1H),6.82(d,J=8.3Hz,1H),4.99(s,2H),4.24-4.14(m,1H),4.03-3.92(m,1H),3 .61(s,3H),2.95(q,J=6.5Hz,2H),2.20(q,J=6.6,5.1Hz,2H),1.81(dq,J=13.4,6.8Hz,1H),1.67(m,3H),1.38(2s,18H),1.30-1.20(m,2H). 13 C NMR(126MHz,CDCl3)δ 172.9,172.6,171.7,156.6,155.8,136.7,128.6,128.5,128.2,128.1,81.1,80.2,66.7,5 4.3,52.5,51.9,40.6,39.4,31.9,31.8,28.6,28.3,28.2,27.3,22.3,21.2.HRMS(MALDI):C 29 H 45 KN3O9 + [M+K] +Calculated m / z for: 618.27930, found 618.27661.

[0068] (S)-4-Carboxy-1-(((R)-6-(4-(4-iodophenyl)butanamido)-1-methoxy-1-oxohexan-2-yl)amino)-1-oxobutan-2-aminium chloride (9). A vacuum flask containing 8 (3.4 g, 5.86 mmol) and Pd / C (0.34 g, 10% mass equiv.) in MeOH (60 mL) was charged with H2 under balloon pressure. The reaction was continuously stirred until complete by TLC. The Pd / C was filtered using a celite pad, the filtrate was concentrated under reduced pressure, and the remaining residue was dried under high vacuum and carried on to the next step without further purification. A solution of 4-(4-iodophenyl)butanoic acid (1.7 g, 5.86 mmol) and HBTU (2.23 g, 5.86 mmol) was stirred at room temperature under Ar in anhydrous DMF (10 mL) for 30 min. A solution of CBz deprotected amine (2.74 g, 6.15 mmol) and anhydrous Et3N (1.53 mL, 8.79 mmol) in DMF (10 mL) was added to the reaction solution and the reaction was stirred under Ar for 6 h. The reaction was diluted with EtOAc (150 mL) and washed sequentially with 1N HCl (75 mL, 3x), saturated NaHCO3(aq) (75 mL, 2x), and brine (75 mL, 1x). The organic layer was dried over Na2SO4, the volatiles were removed under reduced pressure, and the resulting residue was dried under high vacuum and carried on to the next step without further purification. The isolated yield was 85%. Pre-9 1H NMR (400MHz, DMSO-d6) δ 8.13(d,J=7.7Hz,1H),7.74(t,J=5.6Hz,1H),7.62(d,J=8.2Hz,2H),7.00(d,J= 8.2Hz,2H),6.82(d,J=8.3Hz,1H),4.19(td,J=8.5,5.2Hz,1H),3.99(dt,J=22.0 ,7.6Hz,1H),3.60(s,3H),2.98(hept,J=6.3Hz,2H),2.19(q,J=6.8,6.1Hz,2H), 2.03(t,J=7.4Hz,2H),1.69(m,5H),1.38(2s,18H),1.24(q,J=7.0Hz,2H).Pre-9 13 C NMR(126MHz,CDCl3)δ 173.33,173.03,172.57,171.68,155.86,141.32,137.46,130.73,91.06,81.21,80.33,54.72,5 2.59,51.75,39.13,35.60,34.82,31.97,31.83,28.55,28.37,28.31,28.16,27.07,22.28.Pre-9 HRMS(MALDI):C 31 H 48 IN3NaO8 + [M+Na] + Calculated m / z for: 740.23783, found 740.24152. In a dry vacuum flask, a solution of the Boc-protected amine (0.099 g, 0.137 mmol) was stirred continuously in 4N HCl-1,4-dioxane (1 mL) at room temperature for 1 h. The volatiles were removed by rotary evaporation and the resulting residue was dried under high vacuum to give an off-white solid in quantitative yield. 1H NMR (400 MHz, DMSO-d6)δ 8.95(d,J=7.5Hz,1H),8.23(d,J=5.3Hz,3H),7.79(t,J=5.6Hz,1H),7.64-7.56 (m,2H),7.02-6.95(m,2H),4.23(q,J=7.7Hz,1H),3.85(d,J=5.8Hz,1H),3.61(s ,3H),3.02-2.93(m,2H),2.30(h,J=10.2,9.7Hz,2H),1.99(dt,J=19.2,7.0Hz, 4H),1.69(dp,J=28.2,7.5Hz,4H),1.34(q,J=7.0Hz,2H),1.25(d,J=8.0Hz,2H). 13 C NMR(126MHz,DMSO-d6)δ 173.3,172.1,171.7,168.4,141.7,137.0,130.9,91.4,66.4,52.3,52.0, 51.5,38.0,34.7,34.1,30.4,29.2,28.6,26.9,26.5,22.7.HRMS(MALDI):C 22 H 34 ClIN3O6 + [M+H] + についてのm / z calculated value: 598.14160, measured value 598.14044;C 22 H 33 ClIN3NaO6 + [M+Na] + についてのm / z calculated value: 620.12361, measured value 620.12140.

[0069] Compound 10. To a stirred solution of 9 (0.184 g, 0.308 mmol) and NaHCO3 (0.0801 g, 0.800 mmol) in ddH2O (2 mL) was added a solution of DBCO-PEG4-NHS (0.1 g, 0.154 mmol) in 1,4-dioxane (2 mL). The reaction was stirred at ambient temperature for 3 h. ddH2O (10 mL) was added to the reaction solution and the pH was slowly adjusted to 2 via 1N HCl. More ddH2O (10 mL) was added and the organics were extracted into EtOAc (20 mL, 3x). The organic layers were combined and dried under Na2SO4, followed by removal of the solvent under reduced pressure, and the resulting residue was purified by silica gel flash chromatography (14% MeOH in CH2Cl2 → 20% MeOH in CH2Cl2) to give a yellow solid in 70% yield. TLC: Rf=0.194 (15% MeOH in CH2Cl2, visualized by UV). 1 H NMR(600MHz,CD3OD)δ 7.62(dd,J=7.6,1.4Hz,1H),7.58-7.52(m,2H),7.45(m,1H),7.43-7.38(m,2H),7.31(m,2H),7.22(dd,J=7.5,1.5Hz,1 H),6.97-6.92(m,2H),5.09(d,J=14.0Hz,1H),4.40(m,1H),4.35(m,1H),3.70-3.61(m,6H),3.61-3.46(m,13H),3.25-3 .19(m,1H),3.17-3.04(m,3H),2.56-2.38(m,5H),2.32(td,J=7.3,3.6Hz,2H),2.30-2.25(m,2H),2.14(t,J=7.5Hz,2H) ,2.02(ddt,J=23.2,16.0,7.0Hz,2H),1.92-1.76(m,4H),1.71-1.62(m,1H),1.44(dp,J=19.9,6.6Hz,2H),1.32(m,2H). 13C NMR(151MHz,CD3OD)δ 175.6,174.1,173.9,173.8,173.1,152.5,149.5,142.8,138.5,133.5,131.8, 130.5,130.0,129.7,129.2,128.9,128.1,126.5,124.3,123.4,115.6,108.7,9 1.5,71.1,70.9,68.3,68.1,56.56,54.1,53.6,52.8,49.9,39.9,37.2,37.1,3 6.6,36.3,35.7,35.4,32.1,32.0,29.8,29.7,28.9,28.5,24.2.HRMS(MALDI):C 52 H 66 IN5NaO 13 + [M+Na] + m / z calculated for: 1118.35940, found 1118.36194; C 52 H 66 IKN5O 13 + [M+K] + Calculated m / z for: 1134.33334, found 1134.33423.

[0070] Compound 11. To a stirred solution of 42 (0.35 g, 0.319 mmol) and DIPEA (0.068 mL, 0.383 mmol) in anhydrous DMF (6 mL) was added TsTu (0.096 g, 0.319 mmol) in one portion under argon. The reaction was stirred at ambient temperature for 3 h. A solution of CTT1298 (0.322 g, 0.415 mmol) and KHCO3 (0.064 g, 0.639 mmol) in ddH2O (4 mL) was added to the reaction solution and the reaction was stirred continuously overnight. The volatiles were removed under reduced pressure and the resulting residue was purified by reverse phase flash chromatography (100% H2O → 100% MeOH) to give a yellow solid in 51% yield. TLC: Rf = 0.37 (70% MeOH in H2O, UV visualization). 1H NMR(600MHz,D2O)δ 7.69(d,J=7.6Hz,1H),7.63(d,J=7.9Hz,2H),7.55-7.41(m,6H),7.37(d,J=7.6Hz,1H),6.99(d,J=8.0Hz,2H),5.09(d,J=14.3Hz,1H),4.37(dd,J=9.4,4.9Hz,1H),4.33-4.27(m,1H),4.15(dd,J=8.7,4.7Hz,1H),4.10(dd,J=8.3,4.9Hz,1H),3.80-3.55(m,26H),3.54-3.47(m,1H),3.20(dt,J=12.3,5.7Hz,1H),3.10(dq,J=28.9,7.0Hz,6H),2.82(d,J=1.0Hz,1H),2.56(m,4H),2.50-2.16(m,17H),2.16-2.02(m,3H),1.87(m,10H),1.72(m,3H),1.65-1.53(m,5H),1.48(m,5H),1.38-1.24(m,5H). 31 P NMR(234MHz,D2O)δ 7.32. 13 C NMR(126MHz,D2O)δ 183.9,182.5,182.4,180.2,179.3,177.2,175.9,175.7,175.2,174.7,174.6,174.3,174.0,173.3,151.6,148.7,142.5,138.2,133.2,131.7,130.2,129.7,129.5,129.0,127.9,126.5,123.6,122.6,115.7,109.1,92.3,70.7,70.6,70.6,70.6,70.5,67.8,67.6,65.4,65.3,57.6,56.4,55.8,54.3,53.7,53.5,40.3,39.9,39.7,36.9,36.8,36.6,36.5,36.4,35.3,34.9,34.8,33.4,33.1,33.0,32.9,31.1,29.2,29.1,29.0,28.3,28.1,27.9,27.8,26.8,25.9,25.8,23.6.HRMS(MALDI):C 73 H 101 IKN9O 25 P + [M+K] +Calculated m / z for: 1700.53225, found 1700.53699.

[0071] Compound 3. To a stirred solution of 11 (0.29 g, 0.157 mmol) in ddH2O (5 mL) was added 1N KOH dropwise until pH = 12.5. The reaction was stirred until complete by TLC. The reaction solution was lyophilized to give an off-white solid which was carried on to the next step without further purification. The isolated yield was quantitative. TLC: Rf = 0.42 (70% MeOH in H2O, visualized by UV). 1 H NMR(600MHz,D2O)δ 7.25(d,J=8.1Hz,2H),7.23-7.06(m,6H),6.65(d,J=8.0Hz,2H),3.99(tdd ,J=22.0,8.6,4.8Hz,4H),3.65-3.53(m,5H),3.48-3.24(m,19H),3.03-2. 83(m,7H),2.42(tt,J=11.9,7.6Hz,2H),2.31-2.02(m,16H),1.98(t,J=7. 6Hz,5H),1.86-1.63(m,8H),1.62-1.40(m,10H),1.32(m,5H),1.16(m,5H). 31 P NMR(234MHz,DO)δ 7.35. 13 C NMR(151MHz,D2O)δ 183.1,181.5,181.4,179.3,178.5,176.4,175.0,174.5,173.8,173.1,172.7,172.5,150.5,147.6,141.5,13 7.1,132.2,130.7,129.2,128.7,128.5,128.1,126.9,125.5,122.5,121.6,114.7,108.1,91.4,69.6,69.5,69 .4,66.7,66.6,64.4,64.3,56.5,55.4,54.9,53.8,39.3,39.2,38.7,35.8,35.7,35.5,35.4,35.3,34.3,33.8, 33.7,32.3,32.1,32.0,31.9,31.3,28.2,28.0,27.8,27.2,27.0,26.8,26.7,24.9,24.8,22.7.HRMS(MALDI):C72 H 98 IKN9O 25 P + [M+K] + Calculated m / z for: 1685.51729, found 1685.51514. [ka]

[0072] ((Benzyloxy)carbonyl)-L-valine (ZL-Val). The procedure was followed from Olatunji et al. (Tetrahedron Lett. 61, 152398 (2020)) using L-Val (2 g, 17.1 mmol), (2.92 mL, 20.5 mmol), Na2CO3 (3.62 g, 34.1 mmol), and ddH2O (30 mL). The isolated yield was 98%. 1 H NMR(400MHz,CDCl3)δ 7.39-7.28(m,5H),5.26(d,J=9.1Hz,1H),5.12(s,2H),4.35(dd,J=9.1,4.5Hz,1H) ,2.24(dtd,J=13.8,6.9,4.1Hz,1H),1.01(d,J=6.9Hz,3H),0.93(d,J=6.9Hz,3H).

[0073] 2,5-Dioxopyrrolidin-1-yl((benzyloxy)carbonyl)-L-valinate (ZL-Val-OSu). A solution of ZL-Val (2 g, 7.96 mmol) and HBTU (3.02 g, 7.96 mmol) was stirred in anhydrous DMF (14 mL) at room temperature for 30 min under Ar. A solution of N-hydroxylsuccinimide (1.09 g, 9.55 mmol) and anhydrous Et3N (2.08 mL, 11.9 mmol) in DMF (14 mL) was added to the reaction solution and the reaction was stirred under Ar for 3 h. The reaction was diluted with EtOAc (180 mL) and washed sequentially with 1N HCl (75 mL, 3x), saturated NaHCO3(aq) (75 mL, 2x), and brine (75 mL, 1x). The organic layer was dried over Na2SO4, the volatiles were removed under reduced pressure, and the resulting residue was dried under high vacuum and carried on to the next step without further purification. The isolated yield was 84%. 1 H NMR(400MHz,CDCl3)δ 7.40-7.28(m,5H),5.30-5.24(m,1H),5.21-5.08(m,2H),4.73-4.65(m,1H),2.84(s,4H),2.41-2.28(m,1H),1.05(2ds,J=6.9Hz,6H).

[0074] 2,5-Dioxopyrrolidin-1-yl 4-(azidomethyl)benzoate (BzN3-Osu). The procedure for the preparation of ZL-Val-NHS described above was followed using BzN3 (0.6 g, 3.39 mmol), NHS (0.468 g, mmol), HBTU (1.28 g, 3.39 mmol), Et3N (0.89 mL, 5.08 mmol), and DMF (22 mL). The product was carried on to the next step without further purification. The isolated yield was 98%. 1 H NMR(400MHz,CDCl3)δ 8.20-8.13(m,2H),7.47(d,J=8.2Hz,2H),4.47(s,2H),2.92(s,4H).

[0075] (S)-2-(((benzyloxy)carbonyl)amino)-5-ureidopentanoic acid (ZL-Cit). The procedure described by Olatunji et al. was followed using L-Cit (2 g, 17.1 mmol), CBzCl (1.96 mL, 13.7 mmol), Na2CO3 (2.42 g, 22.8 mmol), and ddH2O (27 mL). The isolated yield was 88%. 1 H NMR(400MHz,DMSO-d6)δ 12.58(s,1H),7.61(d,J=8.0Hz,1H),7.42-7.26(m,5H),5.93(t,J=5.7Hz,1H),5.38(s,2H),5.03(s,2H),3.93(ddd,J=9.4,7.9, 4.8Hz,1H),3.19-3.14(m,1H),2.93(q,J=6.6Hz,2H),1.75-1.62(m,1H),1.61-1.48(m,1H),1.40(tdd,J=13.4,8.5,4.0Hz,2H).

[0076] Benzyl (S)-(1-((4-(hydroxymethyl)phenyl)amino)-1-oxo-5-ureidopentan-2-yl)carbamate (12). Following the procedure from Mondal et al. (Tetrahedron letters, 59(40), 3594-3599(2018)), ZL-Cit (3g, 9.69mmol), p-aminobenzyl alcohol (1.43g, 11.6mmol), HATU (4.43g, 11.6mmol), DIPEA (6.76mL, 38.8mmol), and DMF (18mL) were used. The mixture was purified by silica gel flash chromatography (10% MeOH in CH2Cl2, 30% CH3CN → 10% MeOH in CH2Cl2, 40% CH3CN) to give a yellow solid in 85% yield. TLC: Rf = 0.21 (10% MeOH in CH2Cl2, 40% CH3CN, UV visualization). 1H NMR (400MHz, DMSO-d6) δ 9.98(s,1H),7.56(t,J=8.6Hz,3H),7.41-7.14(m,7H),5.98(t,J=5.8Hz,1H), 5.42(s,2H),5.10(t,J=5.7Hz,1H),5.03(s,2H),4.43(d,J=5.4Hz,2H),4.14(d dt,J=21.3,10.5,5.3Hz,1H),3.17(d,J=4.8Hz,1H),2.98(ddt,J=36.8,13.2,6 .5Hz,2H),1.59(dtd,J=18.2,14.4,13.5,8.6Hz,2H),1.41(2ds,J=6.9Hz,2H).

[0077] Benzyl ((S)-1-(((S)-1-((4-(hydroxymethyl)phenyl)amino)-1-oxo-5-ureidopentan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)carbamate (13). Following the procedure from Mondal et al., 12 (2.65 g, 6.37 mmol), Pd / C (0.265 g, 10% mass equiv.), Z-Val-Osu (2.14 g, 6.15 mmol), CHCl (40 mL), MeOH (160 mL), and DMF (22 mL) were used. The mixture was purified by silica gel flash chromatography (10% MeOH in CHCl, 10% CHCN → 10% MeOH in CHCl, 30% CHCN) to give a white solid in 65% yield. TLC: Rf = 0.18 (10% MeOH in CHCl, 40% CHCN, UV visualization). 1H NMR (400MHz, DMSO-d6) δ 9.97(s,1H),8.09(d,J=7.6Hz,1H),7.63-7.50(m,2H),7.38-7.21(m,7H),5.98( t,J=5.8Hz,1H),5.41(s,2H),5.10(t,J=5.7Hz,1H),5.04(s,2H),4.42(t,J=6.0 Hz,3H),3.92(dd,J=8.8,6.8Hz,1H),3.09-2.84(m,2H),1.98(h,J=6.7Hz,1H),1 .78-1.50(m,2H),1.39(ddt,J=22.1,13.1,8.3Hz,2H),0.85(2ds,J=6.8Hz,6H).

[0078] 4-(Azidomethyl)-N-((S)-1-(((S)-1-((4-(hydroxymethyl)phenyl)amino)-1-oxo-5-ureidopentan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)benzamide (14). Following the procedure from Mondal et al., 13 (1.47 g, 2.86 mmol), Pd / C (0.147 g, 10% mass equiv.), BzN3-Osu (0.94 g, 3.42 mmol), CHCl (70 mL), MeOH (700 mL), and DMF (10 mL). The mixture was purified by silica gel flash chromatography (10% MeOH in CH2Cl2, 20% CH3CN → 10% MeOH in CH2Cl2, 40% CH3CN) to give a white solid in 74% yield. TLC: Rf = 0.20 (10% MeOH in CH2Cl2, 40% CH3CN, UV visualization). 1H NMR(400MHz,DMSO-d6)δ 9.94(s,1H),8.33(d,J=8.4Hz,1H),8.22(d,J=7.6Hz,1H),7.97-7.83(m,2H),7.61-7.51(m,2H), 7.51-7.41(m,2H),7.26-7.20(m,2H),5.98(t,J=5.8Hz,1H),5.41(s,2H),5.10(t,J=5.7Hz,1H),4 .53(s,2H),4.46-4.31(m,4H),2.99(ddq,J=25.8,13.2,6.6Hz,2H),2.20-2.05(m,1H),1.70(dq, J=13.3,7.9,7.3Hz,1H),1.60(tq,J=9.1,4.6Hz,1H),1.53-1.28(m,2H),0.94(2ds,J=6.4Hz,6H). 13 C NMR(101MHz,DMSO-d6)δ 171.2,170.4,166.3,158.9,138.9,137.6,137.4,134.1,128.2,128.0,130.0,1 18.9,62.6,59.1,53.2,53.1,30.2,29.4,26.8,25.3,19.4,18.9.HRMS(MALDI):C 26 H 34 N8NaO5 + [M+Na] + m / z calculated for: 561.25444, found: 561.25616; C 26 H 34 KN8O5 + [M+K] + Calculated m / z for: 577.22837, measured 577.22974.

[0079] 4-((S)-2-((S)-2-(4-(azidomethyl)benzamido)-3-methylbutanamido)-5-ureidopentanamido)benzyl(4-nitrophenyl)carbonate (15). To a stirred solution of 14 (0.2 g, 0.371 mmol) and pyridine (0.088 mL, 1.11 mmol) in anhydrous DMF (4 mL) under Ar was added a solution of p-nitrophenyl chloroformate (0.112 g, 0.557 mmol) in CHCl (1 mL) dropwise. The reaction was stirred at ambient temperature overnight. The solvent was removed under reduced pressure and the resulting mixture was purified by silica gel flash chromatography (5% MeOH in CHCl→8% MeOH in CHCl) to give a white solid in 53% yield. TLC: Rf=0.35 (10% MeOH in CHCl, UV visualization). 1 H NMR(400MHz,DMSO-d6)δ 8.37-8.28(m,2H),7.97-7.86(m,2H),7.71-7.28(m,8H),5.24(s,2H),4.53(s,2H),4.48-4.29(m,2H),3 .10-2.85(m,2H),2.14(hept,J=6.8Hz,1H),1.78-1.56(m,2H),1.56-1.32(m,2H),0.95(2ds,J=6.9,6H). 13 C NMR(101MHz,DMSO-d6)δ 171.2,171.1,170.8,170.7,170.6,170.5,166.3,166.2,158.9,155.3,151.9,145.2,139.4,139.3,138.9,138.8,134.1,134.0,132. 4,129.6,129.3,128.2,128.0,125.4,122.7,119.0,118.9,70.3,59.0,58.9,53.1,46.2,30.2,29.3,26.8,19.4,18.9.HRMS(MALDI):C 33 H 37 N9NaO9 + [M+Na] + m / z calculated for: 726.26064, found: 726.26434; C 33 H 37 KN9O9 + [M+K] + Calculated m / z for: 742.23458, found 742.23602.

[0080] 4-((S)-2-((S)-2-(4-(azidomethyl)benzamido)-3-methylbutanamido)-5-ureidopentanamido)benzyl((2S)-1-(((2S)-1-(((3R,4S,5S)-1-(3-((1S,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy-5-methyl-1-oxoheptan-4-yl)(methyl)amino)-3-methyl-1-oxobutan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)(methyl)carbamate (4). To a stirred solution of MMAE (0.122 g, 0.171 mmol), pyridine (0.046 mL, 0.568 mmol), and HOBt hydrate (0.00435 g, 0.0284 mmol) in dry DMF (2 mL) was added a solution of 15 (0.1 g, 0.142 mmol) in DMF (2 mL) at room temperature. The solvent was removed under reduced pressure and the crude product was purified by silica gel flash chromatography (8% MeOH in CH2Cl2 → 10% MeOH in CH2Cl2) to give a colorless oil in 81% yield. TLC: Rf = 0.21 (10% MeOH in CH2Cl2, UV visualization). HRMS (MALDI): C 66 H 99 N 13 NaO 13 + [M+Na] + m / z calculated for: 1304.73775, found 1304.74109; C 66 H 99 KN 13 O 13 + [M+K] + Calculated m / z for: 1320.71169, found 1320.70508.

[0081] SMDC1. A solution of 4 (48 mg, 30.5 μmol) in ddHO (2 mL) was added to a solution of 3 (50 mg, 32.5 μmol) in ddHO (2 mL) and the reaction was stirred at ambient temperature for 30 min. The solvent was removed under reduced pressure and the resulting residue was purified by RP-Prep HPLC (5% CHCN in 10 mM NH4OAc → 100% CH3CN, gradient shown below). Fractions containing the desired product were combined, the NHOAc was neutralized with excess KHCO3 (ca. 2 equiv.), the solvent was removed under reduced pressure and the resulting residue was lyophilized overnight. The solid was desalted using a C18 Sep-Pak (100% ddHO → 100% MeOH) to give an off-white solid product in 30%. 31 P NMR(234 MHz,D2O)δ 7.41.HRMS(MALDI):C 138 H 196 IN 22 O 38 P 2- / 2[M-2H] 2- m / z calculated for / 2: 1463.6432, found 1463.6420; C 138 H 196 IN 22 O 38 P 3- / 3[M-3H] 3- m / z calculated for / 3: 975.4262, found 975.4267; C 138 H 196 IN 22 O 38 P 4- / 4[M-4H] 4- Calculated m / z for / 4: 731.3177, found 731.3133. Example 2. Preparation and characterization of SMDC2 [ka]

[0082] Following the synthesis and purification of 1 above, 3 (50 mg, 27.0 μmol), 5 (41 mg, 29.7 μmol), and ddHO (4 mL) were used in an isolated yield of 49%. 31P NMR(234MHz,D2O)δ 9.59,9.35,7.42.HRMS(MALDI):C 138 H 193 IN 20 O 42 P2 2- / 2[M-2H] 2- m / z calculated for / 2: 1483.6051, found 1483.6007, found 1463.6420; C 138 H 193 IN 20 O 42 P2 3- / 3[M-3H] 3- m / z calculated for / 3: 988.7341, found 988.7234, found 975.4267; C 138 H 193 IN 20 O 42 P2 4- / 4[M-4H] 4- Calculated m / z for / 4: 741.2986, found 741.2957.

[0083] Example 3. PSMA Binding: Once characterized, the IC of PSMA 50 The IC values ​​were determined as previously described and were consistent with other PSMA inhibitors in this class. 50 = 24.1 ± 2.1 nM) and SMDC2 (IC 50 = 1.74 ± 0.14 nM) in the nanomolar range.

[0084] Example 4. Evaluation of SMDC1 and SMDC2 in preclinical models of human PCa Efficacy study design: NCr nude mice (6-8 weeks old) were administered 1 × 10 6 PC3 PiP cells (1:1 in saline with Matrigel, total volume 100 μL) were injected subcutaneously into the right hind flank. Tumors were grown to approximately 100 mm 3Tumors were allowed to grow to a size of approximately 2-3 weeks. Treatment consisted of injecting the appropriate compound into the lateral tail vein (100 μL bolus) once a week for the first 6 weeks of the study. Efficacy treatment groups were 8 animals of each of the following: 1) saline, 2) MMAE alone, 0.2 mg / kg (molar equivalent of MMAE conjugated to a small molecule), 3) CTT1700 (structure below), 0.8 mg / kg, 4) 1, 0.8 mg / kg, and 5) 2, 0.8 mg / kg. Tumor size was measured twice weekly for the duration of the study, and mortality was shown for survival curves. Animals were sacrificed when tumor status reached IACUC criteria for euthanasia (tumor burden >1.5 cm in any axis, ulceration, weight loss >20%). Blood was collected via the superficial temporal vein at weeks 0, 4, 7, and 10, and CBCs were measured with triplicate differentials. [ka]

[0085] Compound retention study design (PK study): Three volumes of PBS (pH 7.4) were added to tumor, kidney, and tear tissues, and 10 volumes of PBS (pH 7.4) were added to prostate tissue samples. Tumor, kidney, and prostate samples were homogenized with a homogenizer, and tear tissues were sonicated with a sonicator. Twenty-five microliters of plasma or tissue homogenate were added to a microcentrifuge tube, followed by the addition of 10 μL of internal standard solution and 100 μL of 5 mM ammonium bicarbonate and acetonitrile (25:75 v,v). Samples were then vortexed at high setting for 1 min and centrifuged at 17,200 × g for 10 min. The resulting supernatant was pipetted into an HPLC vial, and 10–20 μL was injected into the LC-MS / MS system. SMDC2 was used as an internal standard for quantification of CTT1700 and SMDC1, and SMDC1 was used as an internal standard for SMDC2. [ 2H8]-MMAE was used as an internal standard for MMAE. The concentrations of CTT1700 (MW 3013.4 g / mol), SMDC2 (MW 3275.7 g / mol), and SMDC1 (MW 3159.6 g / mol) were quantified using a SCIEX (Framingham, MA01701) 4500 LC-MS / MS system consisting of an Exion HPLC and a 4500 mass detector. For quantification of MMAE concentrations, a SCIEX 6500+Qtrap LC-MS / MS system consisting of an Agilent (Palo Alto, CA 94036) 1290 HPLC and a Sciex 6500+QTrap mass detector was used. Chromatography consisted of a gradient using 5 mM ammonium bicarbonate and acetonitrile, and separation was achieved using a Phenomenex (Torrance, CA 90501) Kinetex column (2×50 mm, 2.6 μm). The MRM m / z transitions monitored were CTT1700, SMDC2, SMDC1, MMAE, and [ 2 For H8]-MMAE, the correlation coefficients were 903.1 / 419.0, 990.7 / 419.0, 977.8 / 718.4, 718.5 / 686.5, and 726.5 / 694.5, respectively. The standard curves were linear from 10 to 10,000 ng / mL for CTT1700, SMDC2, and 1, while the MMAE standard curve was linear from 0.01 to 10 ng / mL. For all standard curves, the correlation coefficients were 1 / y 2 Weighted linear regression was used.

[0086] PK parameters were estimated using standard noncompartmental methods with Phoenix WinNonlin (Certara, Princeton, NJ). Plasma parent drug was derived using an IV bolus approach, while all other data were derived using an extravascular approach.

[0087] Consideration To evaluate the efficacy of SMDC1 and 2 in a preclinical model of human PCa, a xenograft tumor model was used, derived from PSMA+PC3-PIP tumor cells implanted subcutaneously into the right hind flank of NCr nude mice (6-8 weeks old). Three weeks after injection of the cells, the average tumor volume was 100 mm. 3 The tumor size reached 1.5 mg / kg, and mice were treated once weekly for 6 weeks via lateral tail vein injection (100 μL bolus) with 0.8 mg / kg SMDC (252.8 nmol / kg SMDC1, 244.2 nmol / kg SMDC2, n=8). Tumor size was measured twice weekly for the duration of the study, and mortality was shown for survival curves 90 days after the first dose. Animals were euthanized if tumor or mouse condition reached IACUC criteria for euthanasia (tumor burden >1.5 cm in any axis, ulceration, mouse weight loss >20%). Blood was collected via the superficial temporal vein at weeks 0, 4, 7, and 10, and complete blood count (CBC) analysis was performed using a triplicate differential. For biodistribution studies, blood samples were obtained 1 and 6 hours after a single 0.8 mg / kg dose, followed by euthanasia at 24, 72, and 120 hours. LC-MS / MS analysis was performed to determine the concentrations of SMDC and MMAE in plasma, tumor, lacrimal gland, kidney, and prostate samples.

[0088] Tumor growth and survival data for control and SMDC1 and 2 treated mice are shown in Figure 2. Saline and MMAE control animals reached the endpoint criteria within 6 weeks of first dose (Figures 2A and 2B). This was expected for MMAE treatment as the cytotoxic agent is known to be non-specific and minimal accumulation of the agent is expected in the tumor and microenvironment. Animals treated with CTT1700 (PSMA-targeted SMDC with a stable phosphoramidate linker) showed moderate efficacy, with all animals reaching endpoint tumor burden within 12 weeks of starting dosing (Figure 2C). In sharp contrast, SMDC1 and 2 showed dramatic efficacy compared to the control. Tumor regression was observed in compound 1 treated animals up to 2 weeks after the last dose, followed by slower tumor growth. Six of eight mice survived 90 days after first dose (Figure 2D). Animals treated with compound 2 showed significant tumor growth regression, with no detectable tumors in any of the mice by day 35 of the first dose (Figure 2E). Survival of mice in the SMDC2 group was statistically higher than the other groups, with all animals surviving at 90 days (Figure 2F). It is important to note that in all groups of mice, body weights remained constant or increased throughout survival, there were no obvious visual signs of toxicity (dirty fur, diarrhea, lethargy), and CBCs were within normal range (data not shown). Based on these data and observations, the dose regimen utilized uniformly in this comparative study is below the maximum tolerated dose (MTD) in immune-compromised nude mice.

[0089] Plasma and tissue biodistribution is shown in Figure 3. Plasma levels of SMDC and released MMAE indicate overall exposure, while levels in kidney and lacrimal gland represent organs where off-target effects with PSMA-targeted agents have been observed in the past. Parent SMDC1 and 2 showed a volume of distribution, i.e., a value between the plasma volume and the extracellular water volume, of 0.106 L / kg and 0.122 L / kg, respectively. This indicates an albumin-binding motif that enhances the half-life and retention of SMDC in plasma. In general, the observed plasma MMAE and parent drug profiles showed parallel, approximately monoexponential profiles. Furthermore, the drug release MMAE elimination half-lives from plasma (t 1 / 2 ), which is shorter than the t of 4.1 hours reported for MMAE when administered directly. 1 / 2These observations indicate a rate-limited elimination with the pharmacokinetics (PK) of the parent drug determining and prolonging MMAE exposure. Plasma concentrations of MMAE were found to be 5 orders of magnitude lower than the parent drug indicating low systemic release of the MMAE payload. In the tumor, the concentrations of the parent drugs were roughly orders of magnitude similar, suggesting similar efficiency in targeting, but MMAE concentrations varied between compounds due to linker stability. A slow decline of CTT1700 and 2 in all tissues was observed over the course of 5 days. Surprisingly, SMDC1 could not be quantified in any other tissues besides the tumor (Table 1). For all parent drugs, MMAE concentrations in tissues appeared to remain constant or decrease over time, while MMAE concentrations in tumors continued to show a steady increase from days 1 to 5. This indicates a slow conversion and selective accumulation of MMAE from parent SMDC in tumor tissues, preferentially to other tissues. Furthermore, SMDC1 and 2 resulted in approximately 6-fold higher absolute tumor MMAE exposure compared to the control SMDC and the non-degradable linker CTT1700. The reported plasma clearance of MMAE of 60 mL / hr corresponds to 47 L / d / kg, allowing the apparent MMAE formation clearance observed in the data to be used to calculate the fraction of parent compound converted to MMAE. The fraction of drug estimated to release MMAE for CTT1700, SMDC1, and SMDC2 was 1%, 38%, and 36%, respectively. This 40-fold difference in MMAE release capacity between CTT1700 versus 1 and 2 was reflected in MMAE tumor concentrations, perhaps the most important index for interpreting efficacy data. [Table 1]

[0090] In summary, the pharmacokinetic performance of the pH-cleavable linker in 2 can be correlated with its superior efficacy when compared to the control CTT1700. The data indicate that the efficient release of payload from 2 reflects the optimal design of its acid-labile linker technology. In addition, the in vivo performance of SMDC2 compared to SMDC1 demonstrates that the acid-labile phosphoramidate linker competes with the Val-Cit linker found in ADCs. Although the efficacy and biodistribution experiments performed are proof-of-concept studies, the results obtained justify the exploration of this new acid-labile linker technology in the context of releasing other clinically relevant payloads, as well as further rigorous pharmacokinetic studies before proceeding to the clinic.

[0091] Examples 5-29. Additional SMDCs according to the present disclosure Additional examples are essentially prepared according to the procedures described above, where an azide is reacted with a targeting molecule to give the corresponding triazole-containing SMDC. The two targeting molecules, or salts thereof, are as follows: [ka] [Table 2-1] [Table 2-2] [Table 2-3] [Table 2-4]

[0092] It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes will be suggested to those skilled in the art in light thereof and are to be incorporated within the spirit and scope of this application and the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference for all purposes.

Claims

1. Compounds of structural formula (I) 【Chemistry 1】 or a pharma- ceutically acceptable salt thereof, wherein: D is -NR ２ a therapeutic or diagnostic agent attached to L via an -, -S-, or -O- moiety; L is an acid cleavable linker; X is a bond or 【Chemistry 2】 and n ranges from 1 to 6; R １ , R ２ , R ３ , and R ４ are independently H, -C １ -C ６ alkyl, or a protecting group, or a pharma- ceutically acceptable salt thereof.

2. 2. The compound of claim 1, wherein D is a therapeutic agent.

3. 2. The compound of claim 1, wherein D is an antiangiogenic agent, a cytotoxic agent, a cytokine, a chemokine, an apoptotic agent, a prodrug, a toxin, an enzyme, a radioisotope, an immunomodulator, an antibiotic, an agent active in the CNS, or a hormone.

4. D is monomethylauristatin E (MMAE), monomethylauristatin F (MMAF), doxorubicin, cabazitaxel, docetaxel, paclitaxel, gemcitabine, imiquimod, 7-ethyl-10-hydroxycamptothecin (SN-38), duocarmycin (DUBA), seco-duocarmycin (seco-DUBA), (R)-5-chloro-N ２ -[4-(4-methylpiperazin-1-yl)phenyl]-N ４ The compound according to any one of claims 1 to 3, which is -[(tetrahydrofuran-2-yl)methyl]pyrimidine-2,4-diamine ((R)-9b), or gemcitabine.

5. 2. The compound of claim 1, wherein D is a diagnostic agent.

6. 2. The compound of claim 1, wherein D is a radioisotope, an imaging agent, a fluorescent dye, a near-IR dye, an enzyme, a chemiluminescent agent, a bioluminescent agent, a paramagnetic ion, an ultrasound label, or a radioacoustic label.

7. D is -NR ２ The compound according to any one of claims 1 to 6, wherein L is linked via -.

8. L, 【Chemistry 3】 wherein R ５ is H, —OH, or —OC １ -C ６ The compound according to any one of claims 1 to 6, which is alkyl.

9. L, 【Chemistry 4】 Wherein R ５ is H, —OH, or —OC １ -C ６ The compound according to any one of claims 1 to 6, which is alkyl.

10. L, 【Chemistry 5】 Wherein R ５ is H, —OH, or —OC １ -C ６ The compound according to any one of claims 1 to 6, which is alkyl.

11. L, 【Chemistry 6】 The compound according to any one of claims 1 to 6,

12. X, 【Chemistry 7】 The compound according to any one of claims 1 to 11,

13. formula: 【Chemistry 8】 wherein R ５ is H, —OH, or —OC １ -C ６ The compound of claim 12, which is alkyl.

14. R ５ The compound of claim 8, 9, 10, or 12, wherein is H.

15. R ５ But, -OCH ３ 13. The compound of claim 8, 9, 10, or 12, wherein

16. R １ , R ２ , and R ３ are independently H or -C １ -C ４ The compound according to any one of claims 1 to 15, which is alkyl.

17. R １ , R ２ , and R ３ The compound of any one of claims 1 to 15, wherein is independently H or methyl.

18. R １ , R ２ , and R ３ The compound of any one of claims 1 to 15, wherein is independently H.

19. R ４ The compound according to any one of claims 1 to 15, wherein is H or methyl.

20. R ４ The compound according to any one of claims 1 to 15, wherein is H.

21. The compound according to any one of claims 1 to 7, which is of the following formula: 【Chemistry 9】 。

22. The compound according to any one of claims 1 to 7, which is of the following formula: 【Chemistry 10】 。

23. 23. The compound of claim 21 or 22, wherein D is MMAE.

24. 24. The compound according to any one of claims 1 to 23, wherein n is in the range of 2 to 4.

25. The compound according to any one of claims 1 to 23, wherein n is 3.

26. A pharmaceutical composition comprising a compound according to any one of claims 1 to 25 and a pharma- ceutically acceptable excipient, carrier, adjuvant, stabilizer and / or diluent.

27. A method of delivering a therapeutic or diagnostic agent to a subject, comprising administering a therapeutically effective amount of a compound according to any one of claims 1 to 25, or a pharmaceutical composition according to claim 26, to a subject in need of such an agent, wherein D is a therapeutic or diagnostic agent.

28. 27. A method of treating a patient having prostate cancer, comprising administering to said patient an effective amount of a compound according to any one of claims 1 to 25, or a pharmaceutical composition according to claim 26.

29. 27. A method for imaging one or more prostate cancer cells in a patient, comprising administering to the patient a compound according to any one of claims 1 to 25, or a pharmaceutical composition according to claim 26.

30. A method for synthesizing a compound of formula (I) according to any one of claims 1 to 25, comprising the steps of: 【Chemistry 11】 or a pharma- ceutically acceptable salt thereof, Compound of formula (III) 【Chemistry 12】 or a pharma- ceutically acceptable salt thereof, wherein D, L, n, R １ , R ２ , R ３ , and R ４ is as provided above with respect to formula (I).

31. 31. The method of claim 30, wherein said contacting is under copper-free conditions.

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