PLK1 degradation inducing compounds with increased rigidity

Abstract

The invention discloses a novel PLK1 degradation agent based on a dihydropteridinone derivative or a pyrimidino diaza # imgabs0 # ketone derivative. The PLK1 degradation agent of the present invention is a proteolytic targeting chimera (PROTAC) that recruits the PLK1 protein into the CRBN E3 ubiquitin ligase via an optimized rigid linker. The compounds can induce PLK1 degradation and have improved drug properties, and can be used, for example, as a payload for antibody-drug conjugates (ADCs) for the treatment of cancer.

Description

Technical Field

[0001] The present disclosure relates to novel PLK1 degradation-inducing compounds, methods for preparing the same, and uses thereof. Background Art

[0002] Polo-like kinase 1 (PLK1) is a serine / threonine kinase that is widely distributed in eukaryotic cells and plays an important role in several stages of the cell cycle. PLK1 has long been considered a potential drug target for cancer treatment, and several PLK1 inhibitors have been evaluated in clinical trials. Among them, BI-2536 is a first-of-its-kind, highly selective, ATP-competitive small molecule based on a dihydropteridinone derivative that inhibits PLK1 enzymatic activity by blocking the ATP binding site. BI-2536 has also been found to be a potent BRD4 inhibitor, demonstrating its potential as a single, multipharmacologically targeted compound. However, conventional PLK1 inhibitors fail to fully inhibit PLK1 activity at clinically safe concentrations, and most of these have failed or been discontinued in clinical trials. This suggests that pharmacological mechanisms that inhibit enzyme activity by binding to the active site of PLK1, such as small molecule inhibitors, are insufficient for the development of new drugs designed to produce anticancer effects by inhibiting PLK1 activity in cancer cells.

[0003] Proteolysis targeting chimeras (PROTACs) are bispecific molecules containing a target protein binder and an E3 ubiquitin ligase binder connected by a linker. By recruiting the ubiquitin ligase to the target protein, PROTACs can promote the proteasomal degradation of the target protein. Because depletion of oncogenic proteins in cancer cells can achieve better therapeutic efficacy than inhibition of the same protein, PROTACs have been developed as a new therapeutic modality in the field of anticancer therapy.

[0004] Regarding PLK1 degradation PROTAC, CN109879877A discloses PLK1 / BRD4 dual-targeting PROTAC. The inventors focus on BRD4 and PLK1 as attractive therapeutic targets in acute myeloid leukemia (AML), and also show PROTAC-induced degradation of both BRD4 and PLK1 proteins and proliferation inhibition activity in human acute leukemia cells (Mu, Xupeng et al. "Protein targeting chimeric molecules specific for dual bromodomain 4 (BRD4) and Polo-like kinase 1 (PLK1) proteins in acute myeloid leukemia cells." Biochemical and biophysical research communications 521.4 (2020): 833-839.).

[0005] However, CN109879877A discloses only limited PROTAC designs in which dihydropteridinone derivatives are tethered to thalidomide derivatives (which are cereblon (CRBN) conjugates) via alkyl or PEG linkers. The PROTAC field is currently undergoing an important shift from alkyl and polyethylene glycol, which are easy to synthetically manipulate, to optimized rigid and functional linkers, so that the flexibility or freedom of the ternary complex is reduced while maintaining the degrader potency (Troup, Robert I., Charlene Fallan and Matthias GJ Baud. "Current strategies for the design of PROTAC linkers: a critical review." Exploration of Targeted Anti-tumor Therapy 1.5 (2020): 273.).

[0006] It is currently believed that the linker is not just a simple connector connecting the protein of interest (POI) and the E3 warhead. Instead, it plays a specific role in the degradation efficacy and efficacy of PROTAC by participating in the formation of a ternary complex. In addition, the physicochemical characteristics of PROTAC (e.g., efficacy, solubility or stability) may vary depending on the linker used. In view of this, it is necessary to improve the linker structure (including replacing the early alkyl / PEG linker) to develop therapeutically effective PROTAC compounds. However, the discovery of PROTAC linkers that form target-specific stable ternary complexes that result in sufficient target protein degradation effect remains a very challenging task and requires a lot of empirical trial and error in this field.

[0007] The applicant has previously developed PLK1-targeted PROTACs with target degradation effects using different PLK1 binding moieties (WO2021 / 194318A1, WO2021 / 194319A1, WO2021 / 194320A1, WO2021 / 194321A1). However, due to the structural complexity and dynamics of the ternary complex, predicting the combination of anchor / linker / warhead that leads to optimal degradation is a daunting challenge. In this context, by introducing PROTAC linkers based on amine and ring conformations with rigid properties, the inventors successfully synthesized the following novel optimized PLK1 degraders: which have efficient PLK1 degradation and can have improved pharmacological characteristics for PROTAC-based drugs. Summary of the Invention

[0008] Technical issues

[0009] The main purpose of the present invention is to provide alternative novel PLK1 degraders with increased rigidity through linker optimization.

[0010] Technical Solution

[0011] To achieve this, the present invention provides novel PROTAC compounds with a rigid linker through the insertion of two saturated 6-membered rings, optionally mediated by a short chain with limited variation.

[0012] Design of novel PLK1 degraders

[0013] In one general aspect, the present disclosure provides novel compounds represented by the following Formula I:

[0014] [Formula I]

[0015]

[0016] in:

[0017] L1 is a covalent bond or -(X5) 1～3 -, wherein X5 is each independently -CH2- or -NH-, provided that -NH- is absent or occurs at most once in L1;

[0018] L2 is a covalent bond or -(X6) 1～3 -, wherein X6 is each independently -CH2-, -C(O)-, -NH- or -CH(NH2)-, provided that -C(O)-, -NH-, -N(CH3)- and -CH(NH2) are each independently absent or present at most once in L2;

[0019] L3 is Among them, L3 passes covalently bonded to X4;

[0020] X1, X2, X3 and X4 are each independently CH or N;

[0021] X7 and X 8a Each is independently a covalent bond or -CH2-;

[0022] X 8b is -H or -CH3; and

[0023] R1 is -OCH3 or -OCF3;

[0024] wherein ULM is a moiety represented by the following formula II-1, II-2 or II-3:

[0025] [Formula II-1]

[0026]

[0027] [Formula II-2]

[0028]

[0029] [Formula II-3]

[0030]

[0031] in:

[0032] Ring U is phenyl or a 5- or 6-membered heteroaryl group;

[0033] U1 is -NH-, -NHCH2-, -NHCH2CH2-, -CH2NH-, -CH2CH2NH-, -NHCO-, -CONH- or -O-;

[0034] U2 is CH2 or C(O); and

[0035] R U It's a halogen.

[0036] In formula 1, is a PROTAC linker characterized by two saturated 6-membered rings The ULM and PTM are tethered in the para position, optionally mediated by short chains L1, L2, and L3. The rigid nature of the PROTAC linker may contribute to a more stable conformation in the CRBN E3 ligase-PLK1 interaction and present PLK1 within the ubiquitination zone.

[0037] In one embodiment, one to three of X1 to X4 are N. The present invention notes that the piperidine or piperazine ring carries a basic center formed by a protonatable amino group and thus can have a key role as a linker moiety and improve rigidity and solubility when protonated.

[0038] In Formula 1, L1, L2, and L3 mediate the two saturated 6-membered rings described above and may contribute to the overall favorable rigidity and solubility of the PROTAC linker within Formula 1.

[0039] In L1 of Formula 1, -(X5) 1～3 - represents that -(X5)- units are sequentially linked one to three times, wherein each -(X5)- unit may be the same or different.

[0040] In one embodiment, L1 is a covalent bond, wherein ULM is linked to X1 via a covalent bond.

[0041] In one embodiment, L1 is -(CH2) 1～3 -, for example -CH2-, -CH2CH2- or -CH2CH2CH2-, wherein -NH- is absent in L1.

[0042] In one embodiment, L1 is -NH-, -NHCH2-, -CH2NH-, -NHCH2CH2-, -CH2NHCH2-, or -CH2CH2NH-, wherein -NH- is present once in L1.

[0043] In L2 of Formula 1, -(X6) 1～3 - represents that -(X6)- units are sequentially linked one to three times, wherein each -(X6)- unit may be the same or different.

[0044] In one embodiment, L2 is a covalent bond, wherein the two 6-membered rings are linked via a covalent bond.

[0045] In one embodiment, L2 is -(CH2) 1～3 -, such as -CH2-, -CH2CH2- or -CH2CH2CH2-, wherein the functional group is not present in L2.

[0046] In one embodiment, L2 is -(R x )-、-(R x )-CH2-、-CH2-(R x )-、-(R x )-(R x )-、-(R x )-CH2-CH2-、-CH2-(R x )-CH2-、-CH2-CH2-(R x)-、-(R x )-(R x )-CH2-、-(R x )-CH2-(R x )-、-CH2-(R x )-(R x )-or-(R x )-(R x )-(R x )-, where R x is -C(O)-, -NH-, -N(CH3)- or -CH(NH2); and each unit –(R x Thus, -C(O)-, -NH-, -N(CH3)-, or -CH(NH2) is present once in L2 (if any).

[0047] In one embodiment, L3 is The amide groups can mediate an interaction network involving residues in the N- and C-lobes of PLK1, where the NH and CO groups form hydrogen bonds with key PLK1 amino acid residues (e.g., the backbone carbonyl of the glycine-rich loop LEU 59 residue and the side chain of ARG 57 residue), respectively.

[0048] In one embodiment, L3 is The oxadiazole group can further improve PROTAC properties, including metabolic stability.

[0049] The proposed PROTAC linker design in Formula 1 was optimized for anchor / linker / warhead, thus leading to improved physicochemical properties and potent potency.

[0050] The ULMs represented by Formula II-1 or II-2 are CRBN ligands in which a glutarimide is conjugated to a phenyl or heteroaryl ring, either directly or mediated through a short chain moiety.

[0051] In formula II-1, ring U can be phenyl or a 5- or 6-membered heteroaryl group, including pyrrolyl, furyl, thienyl, oxazolyl, isoxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl or pyrazolyl. In one embodiment, ring U is phenyl or pyridinyl.

[0052] In one embodiment, Formula II-1 is selected from the following:

[0053]

[0054] In formula II-1, L1 and the glutarimide moiety in formula II-1 can be attached to ring U at the ortho, meta, or para position. In one embodiment, they are attached at the para position.

[0055] In one embodiment, Formula II-1 is selected from the following:

[0056]

[0057] In formula II-2, U1 can be -NH-, -NHCH2-, -NHCH2CH2-, -CH2NH-, -CH2CH2NH-, -NHCO-, -CONH-, or -O-. In one embodiment, U1 is -NH-.

[0058] In one embodiment, Formula II-2 is as follows:

[0059]

[0060] In formulae II-1, II-2 and II-3, R U Can be fluorine, chlorine, bromine or iodine. In one embodiment, R U It's fluorine.

[0061] In one embodiment of the present disclosure, Formula I is the following Formula I-1:

[0062] [Formula I-1]

[0063]

[0064] Among them L 1a It is -CH2-, -NH-, -CH2CH2-, -NHCH2-, -CH2NH-, -CH2CH2CH2-, -NHCH2CH2-, -CH2NHCH2- or -CH2CH2NH-.

[0065] In one embodiment of the present disclosure, Formula I is the following Formula I-2:

[0066] [Formula I-2]

[0067]

[0068] in:

[0069] X9 is -CH2- or -CH(NH2)-.

[0070] In one embodiment of the present disclosure, Formula I is the following Formula I-3:

[0071] [Formula I-3]

[0072]

[0073] where X 10 is a covalent bond, -NH- or -CH(NH2)-; and X 11It is a covalent bond or -CH2-.

[0074] In one embodiment of the present disclosure, Formula I is the following Formula I-4:

[0075] [Formula I-4]

[0076]

[0077] in:

[0078] L 1b It is a covalent bond or -CH2NH-;

[0079] L 2b Is a covalent bond; -CH2NH-, -CH2N(CH3)- or -CH2CH(NH2)C(O)-;

[0080] X 8a is a covalent bond or -CH2-; and X 8b It is -H or -CH3.

[0081] In one embodiment of the present disclosure, the compound represented by Formula I is selected from Compounds 1 to 25.

[0082] [Table 1]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088] In another general aspect, there is provided a compound represented by the following formula III:

[0089] [Formula III]

[0090]

[0091] in:

[0092] L2 is -CH2-, -NHCH2-, -CH2NH-, -CH(NH2)CH2-, -CH2CH(NH2)-, or -CH2CH2C(O)-;

[0093] X1, X2, X3 and X4 are each independently CH or N;

[0094] X7 is a covalent bond or -CH2-;

[0095] R 2a and R 2b is -halogen; or R 2a and R 2b are linked to each other to form a 3- to 6-membered ring, such as a cyclopropane ring; and

[0096] R3 is -C 1-3 alkyl or 3- to 7-membered cycloalkyl; for example, isopropyl or cyclopentyl,

[0097] wherein ULM is a moiety represented by the following formula II-4:

[0098] [Formula II-4]

[0099]

[0100] wherein U3 is a covalent bond or -NH-; and R U It's a halogen.

[0101] In one embodiment of the present disclosure, the compound represented by Formula III is selected from Compounds 26 to 31.

[0102] [Table 2]

[0103]

[0104]

[0105] PROTAC linkers can contain various types of functional groups, including amines, amides, ethers, alkylamines, single C-C bonds, multiple C-C bonds, etc. One of the other alternative groups (including a cyclic backbone of piperidine or piperazine) can impart some rigidity to the linker, which can be further adjusted by additional groups (Desantis, Jenny et al. "PROTACs bearing piperazine-containing linkers: what effect on their protonation state?" RSCadvances 12.34(2022):21968-21977).

[0106] While the basic properties of these functional groups can serve as a starting point for optimizing PROTAC design, achieving successful PROTAC linker design is extremely challenging because even at a basic level it is impossible to predict which combination of anchor, linker, and warhead will lead to target protein degradation (Troup, Robert I., Charlene Fallan, and Matthias GJ Baud. "Current strategies for the design of PROTAC linkers: a critical review." Exploration of Targeted Anti-tumor Therapy 1.5 (2020): 273.).

[0107] In this context, the present inventors have revealed newly designed PROTACs with rigid linkers that exhibit sufficient levels of PLK1 degradation efficiency across the entire range represented by Formula I or III. In the field of PROTACs, these surprising results were unforeseen from earlier PROTACs with flexible PEG or alkyl linkers.

[0108] In one embodiment, the compounds of the present disclosure may be in the form of salts (preferably pharmaceutically acceptable salts). In the present disclosure, pharmaceutically acceptable salts refer to any organic or inorganic acid addition salts that are relatively non-toxic, harmless, and have a concentration that has an effective effect on patients, wherein the side effects caused by the salt do not impair the beneficial effects of the novel compounds of the present disclosure.

[0109] In one embodiment, the compounds of the present disclosure may be in the form of a racemate, enantiomer, rotamer, tautomer, N-oxide, or any stereoisomer, as if each were specifically described unless clearly excluded by the context.

[0110] In one embodiment, the compounds of the present disclosure may be in the form of hydrates or solvates thereof.

[0111] In one embodiment, the compounds of the present disclosure may be in the form of chimeric molecules conjugated to functional macromolecules via chemical linkers. In certain embodiments, the macromolecules are biomolecules, including nucleic acids, aptamers, carbohydrates, peptides or fragments thereof, antibodies or fragments thereof.

[0112] Synthesis of novel PLK1 degraders

[0113] In one embodiment, the novel compounds of the present disclosure can be prepared, for example, by the following reaction schemes 1 to 3, by synthetic methods known in the field of organic chemistry or by modifications obvious to those skilled in the art.

[0114] [Reaction Scheme 1]

[0115]

[0116] [Reaction Scheme 2]

[0117]

[0118] [Reaction Scheme 3]

[0119]

[0120] (iii) PTM-linker 1-RG 2b +RG 3a -Linker 2-ULM→

[0121] PTM-Linker 1-Linker 2-ULM → PTM-Linker-ULM

[0122] In the reaction scheme, PTM is

[0123] The linker is And ULM is the same as defined above. In the field of organic synthesis, RG 1 RG 2 RG 2a RG 2b RG 3 RG 3a RG 3b and RG 4 The moiety comprises a suitable reactive group that can be linked to the PROTAC intermediate by forming a covalent bond. The formation of the covalent bond can be achieved by synthetic reactions such as amide formation, ester formation, carbamate formation, urea formation, ether formation, amine formation, as well as single bond formation, double bond formation between carbon atoms, click chemistry, etc., depending on the specific reactive group, but is not limited thereto.

[0124] Each step in the above reaction scheme may include one or more synthetic steps. Isolation and purification of the products can be achieved by standard procedures known to those skilled in the art of organic chemistry.

[0125] Uses of novel PLK1 degraders

[0126] In one embodiment, the novel compounds of the present disclosure are PLK1 degraders that induce degradation of PLK1 protein in cells.

[0127] PLK-1 is an enzyme encoded by the PLK1 (polo-like kinase 1) gene in humans, the protein sequence of which is known in the art (e.g., NCBI reference sequence NP_005021). The structure of the PLK1 protein contains an N-terminal Ser / Thr kinase domain and C-terminal repeats of the polo box domain (PBD). Phosphorylation of the PLK1 protein is directly related to the enzymatic activity of PLK1.

[0128] The PROTACs of the present invention can induce proteasomal degradation of PLK1 in cells by recruiting CRBN ubiquitin ligase to PLK1 (supported by the experimental examples disclosed herein). For example, the present disclosure discloses that compounds 1 to 31 have PLK1 degradation activity (confirmed by luciferase assays in HeLa LgBit cell systems), resulting in inhibitory activity on cancer cell viability (confirmed by cell viability assays in small cell lung cancer (SCLC) cell lines H69 and H526).

[0129] In one embodiment, PROTACs of the present invention have superior therapeutic efficacy compared to the small PLK1 inhibitors from which the PROTACs are derived, by depleting the target protein rather than inhibiting it. Thus, PROTACs of the present invention can be used to treat PLK1-related disorders or conditions where aberrant expression of the PLK1 protein is implicated in the onset and / or progression of the disease.

[0130] In the present disclosure, a PLK1-related disorder or condition refers to any disease or condition that can be treated, delayed, inhibited, or prevented by inducing PLK1 degradation or inhibiting PLK1 activity. PLK1-related disorders or conditions include, but are not limited to, cancer, benign tumors, or neurological diseases.

[0131] In one embodiment, PROTACs of the present invention can have anti-cancer activity against cancer cells expressing PLK1 by depleting PLK1, a key oncogenic regulator of the cell cycle. Such cancers include all cancers that can exhibit preventive or therapeutic efficacy due to inhibition of PLK1 activity, and can be solid cancers or blood cancers. For example, the cancer can be one or more selected from the group consisting of squamous cell carcinoma, small cell lung cancer, non-small cell lung cancer, lung adenocarcinoma, lung squamous cell carcinoma, peritoneal cancer, skin cancer, skin or intraocular melanoma, rectal cancer, anal muscle cancer, esophageal cancer, small intestine cancer, endocrine cancer, parathyroid cancer, adrenal cancer, soft tissue sarcoma, urethral cancer, chronic or acute leukemia, lymphocytic lymphoma, hepatocellular carcinoma, gastrointestinal cancer, gastric cancer, pancreatic cancer, glioblastoma, neuroblastoma, glioma, cervical cancer, ovarian cancer, liver cancer, bladder cancer, liver tumor, breast cancer, colon cancer, colorectal cancer, endometrial cancer or uterine cancer, salivary gland cancer, kidney cancer, prostate cancer, vulvar cancer, thyroid cancer, head and neck cancer, brain cancer, osteosarcoma, bone cancer, large cell lymphoma, adrenocorticoid tumors, tumor), T cell lymphoma / leukemia, neuroendocrine cancer, neuroendocrine tumor, bile duct cancer, etc., but not limited thereto. The cancer includes not only primary cancer but also metastatic cancer.

[0132] Benign tumors include all benign tumors that can exhibit preventive or therapeutic efficacy due to inhibition of PLK1 activity, such as precancerous benign tumors, and can be solid tumors or hematological tumors. For example, the tumor can be one or more selected from the following: Barrett's esophagus, colon adenomas and polyps, breast fibroadenomas and cysts, monoclonal gammopathy of undetermined significance (MGUS), monoclonal lymphocytosis, etc., but are not limited thereto.

[0133] Nervous system diseases include all nervous system diseases that can exhibit preventive or therapeutic efficacy due to the inhibition of PLK1 activity, and specifically can be one or more selected from the following: central nervous system diseases, neurodegenerative diseases, Alzheimer's disease, Parkinson's disease, multiple sclerosis, Huntington's disease, senile dementia, epilepsy, Lou Gehrig's disease, stroke, and nerve damage and axonal degeneration-related disorders after brain or spinal cord injury, but are not limited thereto.

[0134] In order to improve drug activity, any known strategy in the PROTAC field can be applied to the PROTAC of the present invention, including photochemically controllable PROTAC (PHOTAC), hypoxia-activated PROTAC, folate-encapsulated PROTAC, antibody-PROTAC conjugate (Ab-PROTAC) and aptamer-PROTAC conjugate (APC) and BCL-XL PROTAC (Zhao, Chunlong and Frank J. Dekker. "Novel Design Strategies to Enhance the Efficiency of Proteolysis Targeting Chimeras." ACS Pharmacology & Translational Science 5.9 (2022): 710-723.).

[0135] In one embodiment, the PROTACs of the present invention can be used as the payload of an antibody-drug conjugate (ADC) (e.g., an antibody-PROTAC conjugate (Ab-PROTAC)). ADCs are able to deliver cytotoxic payloads specifically to cancer cells, enabling maximum effects on cancer cells while minimizing undesirable effects on non-cancerous cells. Therefore, Ab-PROTACs utilizing the PROTACs of the present invention can be a strategy to improve the tissue and cell type selectivity of PROTACs.

[0136] In one embodiment, the present disclosure provides a pharmaceutical composition comprising a PROTAC of the present invention, wherein the compound is conjugated to an antibody or antigen-binding fragment thereof via a linker.

[0137] In one embodiment, the present disclosure provides an antibody-drug conjugate comprising an antibody or antigen-binding fragment thereof and a PROTAC of the present invention, wherein the compound is conjugated to the antibody or antigen-binding fragment thereof via a linker.

[0138] In certain embodiments, a linker chemically links an antibody or antigen-binding fragment thereof to a PROTAC of the invention, wherein a functional group within the compound is modified to create a covalent bond with the linker moiety. In certain embodiments, the functional group is an amine group within the PROTAC linker or E3L binder portion of the compound.

[0139] In certain embodiments, the antibody or antigen-binding fragment thereof is specific for cancer cells and carries one or more molecules of a compound of Formula I or III. In certain embodiments, the linker is a cleavable or non-cleavable linker.

[0140] The present disclosure also provides pharmaceutical compositions comprising a PROTAC of the present invention and at least one pharmaceutically acceptable carrier. In one embodiment, the pharmaceutical composition comprises an effective amount of at least one PROTAC compound of the present invention and, optionally, an effective amount of one or more other active ingredients for combination therapy. In one embodiment, the pharmaceutical composition comprises more than one pharmaceutically acceptable amount of an additive or excipient.

[0141] Another embodiment of the present disclosure is a method for degrading PLK1 by administering a PROTAC of the present invention to a sample in vitro. The sample may include, but is not limited to, cells, cell culture, body fluids, or tissues of a mammal (including humans).

[0142] Beneficial effects of the present invention

[0143] The novel compounds disclosed herein can induce PLK1 degradation in cells and have improved PROTAC properties, such as potency, target selectivity, solubility, lipophilicity, permeability, stability, and toxicity; therefore, they can be effectively used to treat PLK1-related disorders or conditions.

[0144] Best Mode for Carrying Out the Invention

[0145] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terms used in this specification are only used to describe specific embodiments and are not intended to limit the disclosure.

[0146] The present disclosure provides the synthesis methods and biological activity results of compounds 1 to 31.

[0147] The compounds of the present invention were purified and their structures were analyzed according to the following methods.

[0148] instrument

[0149] LCMS: Shimadzu LCMS-2020

[0150] HPLC: Agilent 1260II LC, Agilent 1200 / G6410B

[0151] NMR: BRUKER AVANCE / 400MHZ

[0152] SFC:SHIMADZU LC-30ADsf

[0153] LCMS analysis

[0154] LCMS data were recorded using a Shimadzu LCMS-2020 equipped with an ESI (electrospray ionization) device. Water containing 0.0375% TFA (solvent A) and ACN containing 0.01875% TFA (solvent B) were used as mobile phases. Kinetex EVOC18 (2.1×30 mm, 5 μm) or HALO C18 (3.0×30 mm, 5 μm) columns were used.

[0155] HPLC analysis

[0156] For HPLC analysis, an Agilent 1260II LC or an Agilent 1200 / G6410B was used. Water containing 0.0375% TFA (solvent A) and ACN containing 0.01875% TFA (solvent B) were used as mobile phases. A Zobrax Eclipse Plus C18 (4.6×150 mm, 3.5 μm) or a YMC ODS A (4.6×150 mm, 3 μm) column was used.

[0157] NMR analysis

[0158] 1 H NMR spectra were recorded using a Bruker AVANCE III 400 MHz / 5 mm probe (BBO).

[0159] SFC analysis

[0160] In the SFC analysis, a SHIMADZU LC-30ADsf was used. CO2 (solvent A) and IPA+ACN containing 0.05% DEA (solvent B) were used as mobile phases. A Chiralpak AD-3 (50×4.6 mm, 3 μm) was used as a column.

[0161] <Example>

[0162] Example 1. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(2-((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)ethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 1)

[0163]

[0164] Step 1. Synthesis of 4-(2,6-bis(benzyloxy)pyridin-3-yl)aniline (2)

[0165] At 20 ° C and N2, to a solution of 2,6-dibenzyloxy-3-bromo-pyridine (6 g, 16.21 mmol) and 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (4.62 g, 21.07 mmol) in dioxane (90 mL) and H2O (9 mL) was added K2CO3 (6.72 g, 48.62 mmol) and Pd(dppf)Cl2 (1.19 g, 1.62 mmol), and the resulting mixture was stirred at 110 ° C for 6 hours. LCMS showed that the raw material was completely consumed and that 57% of the peak had the desired mass. The reaction mixture was concentrated in vacuo. The product was purified by flash chromatography on silica gel (80 g The residue was purified by silica gel flash column (0-20% EtOAc / petroleum ether gradient @ 200 mL / min) to afford 4-(2,6-bis(benzyloxy)pyridin-3-yl)aniline (6.3 g, 16.14 mmol, 99.61% yield, 98% purity) as a yellow oil. MS (M+H) + =383.2

[0166] Step 2. Synthesis of 3-(4-aminophenyl)piperidine-2,6-dione (3)

[0167] Under N2 atmosphere, Pd / C (1 g, 10% purity) was added to a solution of 4-(2,6-bis(benzyloxy)pyridin-3-yl)aniline (6 g, 15.69 mmol) in DCM (50 mL) and MeOH (50 mL). The suspension was degassed and purged with H2 three times. The mixture was stirred at H2 (15 Psi) and 20 ° C for 12 hours. LCMS showed that 44% of the starting material remained and 37% of the peak had the expected mass, and the reaction mixture was stirred at 20 ° C for another 12 hours. LCMS showed that the starting material was completely consumed and a peak with the expected mass was detected. The reaction mixture was diluted with MeOH (100 mL) and filtered. The filtrate was concentrated in vacuo to give 3-(4-aminophenyl)piperidine-2,6-dione (2.4 g, 11.75 mmol, 74.91% yield) as a green solid. MS (M+H) + =205.1

[0168] Step 3. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1-(4-(2-((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)ethyl)piperazin-1-yl)cyclohexane Synthesis of 3-methoxybenzamide (Compound 1)

[0169] To a solution of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-((1r,4R)-4-(4-(2-oxoethyl)piperazin-1-yl)cyclohexyl)benzamide (208.00 mg, 328.70 μmol) in DCM (10 mL) was added TEA (99.78 mg, 986.10 μmol, 137.25 μL) and 3-(4-aminophenyl)piperidine-2,6-dione (80.55 mg, 394.44 μmol) at 20° C. After stirring for 10 minutes, NaBH(OAc)3 (209.00 mg, 986.10 μmol) was slowly added at 20° C. and the resulting mixture was stirred at 20° C. for 2 hours. The product of 1-H-oxo-2-nitropropene was added into the 4-nitropropene (2-nitropropene) mixture of 4-nitropropene (2-nitropropene) and 4-nitropropene (2-nitropropene) (3-nitropropene) (4-nitropropene) (5-nitropropene) (6-nitropropene) (7-nitropropene) (8-nitropropene) (9-nitropropene) (1-nitropropene) (2-nitropropene) (6-nitropropene) (7-nitropropene) (8-nitropropene) (9 ... The product was dissolved in a mixture solution (20 mL, ACN:HO=1:3) and lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(2-((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)ethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (53 mg, 59.39 μmol, 18.07% yield, 92% purity) as a yellow solid. MS (M+H) + =821.2

[0170] 1H NMR (400MHz, DMSO-d6) δ=10.73(s,1H),8.44-8.36(m,1H),8.03(d,J=7.6Hz,1H),7.84(s,1H),7.59(s,1H),7.50-7.45(m,2H) ,6.91(d,J=8.5Hz,2H),6.53(d,J=8.5Hz,2H),5.37-5.24(m,1H),4.35(q,J=7.9Hz,1H),4.27-4.19(m,1H),3.93(s,3H),3.78- 3.68(m,1H),3.64(dd,J=5.0,10.4Hz,1H),3.24(s,3H),3.09(d,J=3.6Hz,2H),2.66-2.56(m,4H),2.48-2.39(m,7H),2.29-2.2 1(m,1H),2.14-1.95(m,4H),1.93-1.84(m,6H),1.80-1.72(m,4H),1.68-1.59(m,3H),1.40-1.28(m,4H),0.76(t,J=7.4Hz,3H)

[0171] Example 2. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 2)

[0172]

[0173] Step 1. tert-Butyl 4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidine-1-carboxylate (3) Synthesis

[0174] A mixture of 3-(4-aminophenyl)piperidine-2,6-dione (700 mg, 3.43 mmol), tert-butyl 4-formylpiperidine-1-carboxylate (657.91 mg, 3.08 mmol) and AcOH (20.58 mg, 342.76 μmol, 19.62 μL) in DCM (20 mL) was stirred at 15 ° C for 0.5 hours, then NaBH (OAc) 3 (3.3 g, 15.57 mmol) was added and the resulting mixture was stirred at 15 ° C for 12 hours. LCMS showed a peak with the desired mass (84%). The mixture was diluted with H2O (20 mL) and then treated with saturated NaHCO3 solution to adjust pH>7. The mixture was extracted with DCM (50 mL×2). The combined organic layers were dried over MgSO4, filtered and concentrated in vacuo. The product was purified by flash chromatography on silica gel (20 g The residue was purified by silica gel flash column (eluent: 20-45% EtOAc / petroleum ether gradient @ 200 mL / min), the eluent was concentrated in vacuo, the residue was diluted with EtOAc (30 mL), and treated with HCl solution (1 M) to adjust the pH to <7. The aqueous phase was washed with EtOAc (30 mL×2), and the EtOAc layer was discarded. The aqueous phase was treated with saturated Na2CO3 solution to adjust the pH>7, extracted with EtOAc (50 mL×3), and the combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo to give tert-butyl 4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidine-1-carboxylate (360 mg, 896.64 μmol, 26.16% yield) as a light blue solid. MS (M+Na) + =424.1.

[0175] Step 2. Synthesis of 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione (4)

[0176] To a solution of tert-butyl 4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidine-1-carboxylate (360 mg, 896.64 μmol) in DCM (10 mL) was added HCl / dioxane (4 M, 15 mL) and the mixture was stirred at 15 °C for 1 hour. LCMS showed that the starting material was completely consumed. The mixture was concentrated in vacuo to give 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione (340 mg, HCl salt) as a white solid, which was used directly in the next step. MS (M+H) + =302.4.

[0177] Step 3. ((1r,4r)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidin-1-yl Synthesis of tert-butyl (6)-(4-(4-cyclohexyl)carbamate (trans)

[0178] A mixture of 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione (380 mg, 1.12 mmol, HCl salt), tert-butyl ((1s,4s)-4-iodocyclohexyl)carbamate (cis) (475.49 mg, 1.46 mmol), NaCO (357.64 mg, 3.37 mmol) and DIPEA (436.11 mg, 3.37 mmol, 587.75 μL) in ACN (10 mL) was stirred at 80° C. for 12 hours. LCMS showed 23% of 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione remaining and 6% of the expected mass was detected. To the mixture was added Na2CO3 (357.64 mg, 3.37 mmol), DIPEA (436.11 mg, 3.37 mmol, 587.75 μL) and tert-butyl ((1s,4s)-4-iodocyclohexyl)carbamate (cis) (182.88 mg, 562.39 μmol) and stirred at 80°C for 2 hours. Additional tert-butyl ((1s,4s)-4-iodocyclohexyl)carbamate (cis) (182.88 mg, 562.39 μmol) was added and the resulting mixture was stirred at 80°C for another 14 hours. LCMS showed 11% of 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione remaining and 60% of the expected mass was detected. To the mixture was added tert-butyl ((1s,4s)-4-iodocyclohexyl)carbamate (cis) To the mixture was added tert-butyl ((1s,4s)-4-iodocyclohexyl)carbamate (cis) (91.44 mg, 281.20 μmol), and the mixture was stirred at 80°C for 2 hours. LCMS showed that 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione remained, and 61% of the expected mass was detected. To the mixture was added tert-butyl ((1s,4s)-4-iodocyclohexyl)carbamate (cis) (365.76 mg, 1.12 mmol), and the resulting mixture was stirred at 80°C for 12 hours. LCMS showed that a trace amount of 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione remained, and about 50% of the expected mass was detected. The mixture was filtered and the filter cake was washed with ACN (40 mL). The filtrate was treated with AcOH to adjust pH <7. The resulting mixture was concentrated in vacuo. The residue was diluted with DCM (40 mL) and washed with H2O (30 mL×2). The organic phase was dried over MgSO4, filtered and concentrated in vacuo.The residue was purified by preparative TLC (SiO, DCM:MeOH = 7:1) to give tert-butyl ((1r,4r)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (63 mg, 126.34 μmol, 11.23% yield) as a brown solid. MS (M+H). + =499.3.

[0179] Step 4. 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)phenyl)piperidin- Synthesis of 2,6-diketone (trans) (7)

[0180] A mixture of tert-butyl ((1r,4r)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (55 mg, 110.30 μmol), HCl / dioxane (4M, 3 mL) in DCM (3 mL) was stirred at 15 ° C for 1 hour. LCMS showed that the starting material was completely consumed and the expected mass was detected. The mixture was concentrated in vacuo to give 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)phenyl)piperidine-2,6-dione (trans) (50 mg, HCl salt) as a brown solid, which was used directly in the next step. MS (M+H) + =399.3.

[0181] Step 5. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidin-1-yl)cyclohexane Synthesis of 2-(4-amino-3-methoxybenzamide) (trans) (Compound 2)

[0182] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (35 mg, 82.26 μmol) in DMF (2 mL) were added HATU (46.92 mg, 123.39 μmol) and DIPEA (63.79 mg, 493.56 μmol, 85.97 μL), and the mixture was stirred at 15° C. for 15 minutes. Then, 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)phenyl)piperidine-2,6-dione (trans) (50 mg, 114.94 μmol, HCl salt) was added, and the resulting mixture was stirred at 15° C. for 1 hour. LCMS showed that 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)phenyl)piperidine-2,6-dione (trans) was completely consumed and showed a peak with the desired mass (65%). The mixture was diluted with H2O (40 mL) and extracted with EtOAc (30 mL×3). The combined organic layers were washed with brine (80 mL×5), dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by preparative TLC (SiO2, DCM:MeOH=7:1) and the eluent was concentrated in vacuo. The residue was purified by preparative HPLC (column: Phenomenex luna C18150*25mm*10um; mobile phase: [water (TFA)-ACN]; B%: 31%-51%, 7 minutes). The eluate contained residual DMF, and the eluate was concentrated in vacuo to remove most of the ACN. The residue was treated with NaHCO3 solution (0.5 mL) to adjust the pH to >7 and extracted with DCM (10 mL×3). The organic phase was washed with brine (10 mL×4), dried over MgSO 4 , filtered and concentrated in vacuo, and the residue was diluted with H 2 O (10 mL) and ACN (5 mL) and freeze-dried to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (trans) (15.2 mg, 18.10 μmol, 22.01% yield, 96% purity) as a white solid. MS (M+H) + =806.4.

[0183] 1H NMR (400MHz, DMSO-d6) δ = 10.73 (s, 1H), 8.41 (d, J = 8.9Hz, 1H), 8.16-8.03 (m, 1H ),7.84(s,1H),7.60(s,1H),7.52-7.40(m,2H),6.90(d,J=8.6Hz,2H),6.53(br d,J=8.4Hz,2H),5.77-5.59(m,1H),4.42-4.30(m,1H),4.27-4.19(m,1H),3.94(s,3H),3.84-3.69(m,1H),3 .63(dd,J=5.1,10.8Hz,1H),3.25(s,3H),2.94-2.88(m,2H),2.65-2.58(m,2H),2.47-2.45(m,1H),2.43(br d,J=4.4Hz,1H),2.06(br d,J=4.5Hz,2H),2.05-1.99(m,3H),1.99-1.93(m,3H),1.93-1.84(m,4H),1.83-1.72( m,5H),1.69-1.52(m,5H),1.50-1.33(m,4H),1.28-1.21(m,2H),0.76(t,J=7.4Hz,3H).

[0184] Example 3. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 3)

[0185]

[0186] Step 1. Synthesis of tert-butyl ((1r,4r)-4-(4-benzylpiperazin-1-yl)cyclohexyl)carbamate (trans) (2A) become

[0187] To ((1r, 4r) -4- aminocyclohexyl) tert-butyl carbamate (trans) (2g, 9.33mmol) and N-benzyl -2- chloro-N- (2- chloroethyl) second -1- amine (2.27g, 8.46mmol, HCl) in EtOH (20mL) solution, add NaHCO (3.92g, 46.66mmol, 1.81mL). The mixture was stirred at 85 ° C for 16 hours. LCMS shows that ((1r, 4r) -4- aminocyclohexyl) tert-butyl carbamate (trans) is completely consumed, and the desired quality is detected. The reaction mixture is quenched with H at 25 ° C O (30mL), then extracted with EtOAc (160mL). The organic layer is passed through Na SO Drying, filtered and concentrated under reduced pressure to obtain residue. The residue was triturated with EtOAc at 25 °C for 30 min to give tert-butyl ((1r,4r)-4-(4-benzylpiperazin-1-yl)cyclohexyl)carbamate (trans) (2.1 g, 5.34 mmol, 57.23% yield, 95% purity) as a white solid. MS (M+H) + =374.4.

[0188] Step 2. Synthesis of tert-butyl ((1r,4r)-4-(piperazin-1-yl)cyclohexyl)carbamate (trans) (3A)

[0189] To a solution of tert-butyl ((1r, 4r)-4-(4-benzylpiperazin-1-yl)cyclohexyl)carbamate (trans) (2.1 g, 5.62 mmol) in EtOH (20 mL) was added Pd / C (500 mg, 10% purity) and Pd(OH) / C (500 mg, 20% purity) under a N atmosphere. The suspension was degassed and purged with H three times. The mixture was stirred under H (30-40 Psi) at 25° C. for 16 hours. TLC (DCM:MeOH=10:1) indicated that tert-butyl ((1r, 4r)-4-(4-benzylpiperazin-1-yl)cyclohexyl)carbamate (trans) was completely consumed and a new spot formed. The mixture was filtered, and the filtrate was concentrated under reduced pressure to give tert-butyl ((1r,4r)-4-(piperazin-1-yl)cyclohexyl)carbamate (trans) (1.52 g, 5.36 mmol, 95.40% yield) as a white solid.

[0190] Step 3. Synthesis of 3-(4-aminophenyl)propan-1-ol (2)

[0191] At 0 ° C, BH3-Me2S (10M, 4.84mL) was added to a solution of 3-(4-aminophenyl)propanoic acid (2g, 12.11mmol) in THF (30mL). The mixture was stirred at 25 ° C for 2 hours. LCMS showed that 3-(4-aminophenyl)propanoic acid was completely consumed and the expected mass was detected. At 0 ° C, the reaction mixture was poured into 40mL of HCl (1N) solution. The pH value of the mixture was adjusted to 7.4 with saturated NaHCO3 solution and extracted with EtOAc (120mL). The organic layer was dried over Na2SO4, filtered and concentrated under reduced pressure to give 3-(4-aminophenyl)propan-1-ol (1.82g, 12.04mmol, 99.42% yield) as a brown oil. The crude product was used in the next step without further purification. MS (M+H) + =152.0.

[0192] Step 4. Synthesis of 4-(3-((tert-butyldimethylsilyl)oxy)propyl)aniline (3)

[0193] To 3-(4-aminophenyl)propan-1-ol (1.82g, 12.04mmol) in DCM (20mL) solution, add TBSCl (2.18g, 14.44mmol, 1.78mL) and imidazole (Imid) (1.64g, 24.07mmol). The mixture was stirred at 25°C for 16 hours. LCMS showed that 3-(4-aminophenyl)propan-1-ol was completely consumed, and the desired mass was detected. At 0°C, the reaction mixture was poured into 50mL of HCl (1N) solution, then extracted with EtOAc (100mL). The combined organic layer was dried over Na2SO4, filtered and concentrated under reduced pressure to obtain residue. By flash chromatography on silica gel ( 40g The residue was purified on a silica gel flash column (0-20% EtOAc / petroleum ether gradient @ 50 mL / min) to afford 4-(3-((tert-butyldimethylsilyl)oxy)propyl)aniline (2.9 g, 10.92 mmol, 90.76% yield) as a brown oil. MS (M+H) + =266.1.

[0194] Step 5. 3-((4-(3-((tert-Butyldimethylsilyl)oxy)propyl)phenyl)amino)piperidine-2,6- Synthesis of diketone (5)

[0195] To a solution of 4-(3-((tert-butyldimethylsilyl)oxy)propyl)aniline (2.7 g, 10.17 mmol) and 3-bromopiperidine-2,6-dione (4.88 g, 25.43 mmol) in ACN (15 mL) was added NaHCO 3 (4.96 g, 58.99 mmol, 2.30 mL). The mixture was stirred at 80 ° C for 14 hours. LCMS showed that 4-(3-((tert-butyldimethylsilyl)oxy)propyl)aniline was completely consumed and the desired mass was detected. The reaction mixture was filtered and the filtrate was concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 20g The residue was purified on a silica gel flash column with a 0-17% EtOAc / petroleum ether gradient at 120 mL / min to afford 3-((4-(3-((tert-butyldimethylsilyl)oxy)propyl)phenyl)amino)piperidine-2,6-dione (0.78 g, 2.07 mmol, 20.37% yield) as a blue solid. MS (M+H) + =377.4.

[0196] Step 6. Synthesis of 3-((4-(3-hydroxypropyl)phenyl)amino)piperidine-2,6-dione (6)

[0197] To a solution of 3-((4-(3-((tert-butyldimethylsilyl)oxy)propyl)phenyl)amino)piperidine-2,6-dione (0.78 g, 2.07 mmol) in dioxane (8 mL) was added HCl / dioxane (4 M, 16 mL). The mixture was stirred at 25 ° C for 1 hour. LCMS showed that 3-((4-(3-((tert-butyldimethylsilyl)oxy)propyl)phenyl)amino)piperidine-2,6-dione was completely consumed and the expected mass was detected. The mixture was concentrated under reduced pressure to give 3-((4-(3-hydroxypropyl)phenyl)amino)piperidine-2,6-dione (0.54 g, 2.06 mmol, 99.39% yield) as a blue solid. The product was used in the next step without further purification. MS (M+H) + =263.3.

[0198] Step 7. Synthesis of 3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl 4-methylbenzenesulfonate (7)

[0199] To a solution of 3-((4-(3-hydroxypropyl)phenyl)amino)piperidine-2,6-dione (0.54 g, 2.06 mmol) in DCM (6 mL) was added TEA (624.95 mg, 6.18 mmol, 859.63 μL) and TosCl (588.72 mg, 3.09 mmol). The mixture was stirred at 20 ° C for 12 hours. LCMS showed that 3-((4-(3-hydroxypropyl)phenyl)amino)piperidine-2,6-dione was completely consumed and the expected mass was detected. The mixture was concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 40g The residue was purified using a silica gel flash column (0-50% EtOAc / petroleum ether gradient @ 80 mL / min) to afford 3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl 4-methylbenzenesulfonate (710 mg, 1.62 mmol, 78.67% yield, 95% purity) as a blue solid. MS (M+H) + =417.1.

[0200] Step 8. ((1r,4r)-4-(4-(3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl)piperazine- Synthesis of tert-butyl 1-(1-yl)cyclohexyl)carbamate (trans) (8)

[0201] To a DMF (4mL) solution of 3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl-4-methylbenzenesulfonate (0.4g, 960.41μmol) and tert-butyl-((1r, 4r)-4-(piperazine-1-yl)cyclohexyl)carbamate (trans) (0.45g, 1.59mmol) was added DIPEA (744.76mg, 5.76mmol, 1.00mL) and NaI (28.79mg, 192.08μmol). The mixture was stirred at 25°C for 16 hours. LCMS showed that 3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl-4-methylbenzenesulfonate was completely consumed, and the desired mass was detected. The reaction mixture was quenched with H at 25°C o (20mL), then extracted with EtOAc (120mL). The combined organic layers were washed with brine (20 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 20g The residue was purified on a silica gel flash column using 0-20% MeOH / EtOAc at 50 mL / min as the eluent to afford tert-butyl ((1r,4r)-4-(4-(3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl)piperazin-1-yl)cyclohexyl)carbamate (trans) (0.227 g, 430.17 μmol, 44.79% yield) as a yellow solid. MS (M+H) +=528.3.

[0202] Step 9. 3-((4-(3-(4-((1r,4r)-4-aminocyclohexyl)piperazin-1-yl)propyl)phenyl)amino)piperidin-1-yl) Synthesis of pyridine-2,6-dione (trans) (9)

[0203] To a solution of tert-butyl ((1r, 4r)-4-(4-(3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl)piperazine-1-yl)cyclohexyl)carbamate (trans) (0.1 g, 189.50 μmol) in DCM (0.3 mL) was added TFA (153.50 mg, 1.35 mmol, 0.1 mL). The mixture was stirred at 25 ° C for 1 hour. LCMS showed that tert-butyl ((1r, 4r)-4-(4-(3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl)piperazine-1-yl)cyclohexyl)carbamate (trans) was completely consumed and the desired mass was detected. The reaction mixture was concentrated under reduced pressure to give 3-((4-(3-(4-((1r,4r)-4-aminocyclohexyl)piperazin-1-yl)propyl)phenyl)amino)piperidine-2,6-dione (trans) (0.1 g, 184.64 μmol, 97.43% yield, TFA) as a yellow oil. The product was used in the next step without further purification. MS (M+H) + =428.5.

[0204] Step 10. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl) amino)-N-((1r,4R)-4-(4-(3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl)piperazin-1-yl)cyclohexane Synthesis of (4-(2-hexyl)-3-methoxybenzamide (trans) (Compound 3)

[0205] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (78.56 mg, 184.64 μmol) in DMF (1 mL) was added HATU (105.31 mg, 276.95 μmol) and DIPEA (119.31 mg, 923.18 μmol, 160.80 μL). The mixture was stirred at 25° C. for 0.5 hours. 3-((4-(3-(4-((1r,4r)-4-aminocyclohexyl)piperazin-1-yl)propyl)phenyl)amino)piperidine-2,6-dione (trans) (0.1 g, 184.64 μmol, TFA) was then added to the mixture, and the mixture was stirred at 25° C. for an additional 16 hours. LCMS showed that 3-((4-(3-(4-((1r,4r)-4-aminocyclohexyl)piperazin-1-yl)propyl)phenyl)amino)piperidine-2,6-dione (trans) was completely consumed and the expected mass was detected. The reaction mixture was quenched with H2O (10 mL) at 25°C and then extracted with EtOAc (80 mL). The combined organic layers were washed with brine (10 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 20g The residue was purified by silica gel flash column (0-30% MeOH / EtOAc, 50 mL / min) to afford 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)propyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (trans) (91.6 mg, 104.21 μmol, 56.44% yield, 95% purity) as a white solid. MS (M+H) + =835.4.

[0206] 1H NMR (400MHz, DMSO-d6) δ = 10.77 (s, 1H), 8.45-8.36 (m, 1H), 8.03 (d, J = 7.6Hz, 1H), 7.84 (s, 1H), 7.59 (s, 1H), 7.52-7.42 (m,2H),6.91(d,J=8.3Hz,2H),6.59(d,J=8.3Hz,2H),5.62(d,J=7.3Hz,1H),4.36(t,J=8.0Hz,1H),4.30-4.19(m,2H),3 .93(s,3H),3.77-3.66(m,1H),3.24(s,3H),2.71-2.60(m,1H),2.63-2.55(m,4H),2.45-2.37(m,5H),2.31-2.23(m,3H ),2.18-1.98(m,3H),1.96-1.84(m,7H),1.80-1.70(m,4H),1.68-1.58(m,5H),1.44-1.23(m,5H),0.76(t,J=7.4Hz,3H)

[0207] Example 4. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 4)

[0208]

[0209] Step 1. Synthesis of 4-(2-((tert-butyldimethylsilyl)oxy)ethyl)aniline (2)

[0210] To a solution of 2-(4-aminophenyl)ethan-1-ol (2g, 14.58mmol) in DCM (20mL) was added TBSCl (2.7g, 17.91mmol, 2.2mL) and imidazole (1.2g, 17.63mmol), and the mixture was stirred at 25°C for 14 hours. TLC (petroleum ether: EtOAc = 5: 1) showed a new spot. The mixture was diluted with water (20mL) and extracted with EtOAc (20mL × 2). The combined organic layer was concentrated under reduced pressure. The product was purified by flash chromatography on silica gel (20g The residue was purified on a silica gel flash column (20-30% EtOAc / MeOH gradient @ 50 mL / min) to afford 4-(2-((tert-butyldimethylsilyl)oxy)ethyl)aniline (4.27 g, crude) as a yellow oil. MS (M+H) + =252.4

[0211] Step 2. 3-((4-(2-((tert-Butyldimethylsilyl)oxy)ethyl)phenyl)amino)piperidine-2,6- Synthesis of diketone (4)

[0212] At 20 ° C, to a solution of 4-[2-[tert-butyl(dimethyl)silyl]oxyethyl]aniline (2 g, 7.95 mmol) and 3-bromopiperidine-2,6-dione (2.29 g, 11.93 mmol) in ACN (40 mL) was added DIPEA (3.08 g, 23.86 mmol, 4.16 mL) and the reaction mixture was stirred at 80 ° C for 12 hours. LCMS showed 44% residual 4-(2-((tert-butyldimethylsilyl)oxy)ethyl)aniline and 38% of the peak had the desired mass. The reaction mixture was concentrated in vacuo. The product was purified by flash chromatography on silica gel ( 20g The residue was purified on a silica gel flash column with a 0-25% EtOAc / petroleum ether gradient at 200 mL / min to afford 3-((4-(2-((tert-butyldimethylsilyl)oxy)ethyl)phenyl)amino)piperidine-2,6-dione (806 mg, 2.22 mmol, 27.95% yield) as a brown solid. MS (M+H) + =363.3

[0213] Step 3. Synthesis of 3-((4-(2-hydroxyethyl)phenyl)amino)piperidine-2,6-dione (5)

[0214] To a solution of 3-[4-[2-[tert-butyl(dimethyl)silyl]oxyethyl]aniline]piperidine-2,6-dione (400 mg, 1.10 mmol) in dioxane (5 mL) was added HCl / dioxane (4 M, 10 mL) at 20 ° C., and the mixture was stirred at 20 ° C. for 1 hour. LCMS showed that the starting material was completely consumed and the expected mass was detected. The reaction mixture was combined with another batch (200 mg). The reaction mixture was concentrated in vacuo to give 3-((4-(2-hydroxyethyl)phenyl)amino)piperidine-2,6-dione (600 mg, crude) as a brown solid. MS (M+H) + =249.2

[0215] Step 4. Synthesis of 4-((2,6-dioxopiperidin-3-yl)amino)phenethyl 4-methylbenzenesulfonate (6)

[0216] At 20 ° C, to a solution of 3-((4-(2-hydroxyethyl)phenyl)amino)piperidine-2,6-dione (600 mg, 2.42 mmol) in DCM (8 mL) was added TEA (733.62 mg, 7.25 mmol, 1.01 mL) and TosCl (691.09 mg, 3.62 mmol). The mixture was stirred at 20 ° C for 12 hours. LCMS showed that the starting material was completely consumed and that 58% of the peak had the desired mass. The reaction mixture was concentrated in vacuo. The product was purified by flash chromatography on silica gel (12 g The residue was purified by silica gel flash column (0-50% EtOAc / petroleum ether gradient @ 100 mL / min) to afford 4-((2,6-dioxopiperidin-3-yl)amino)phenethyl 4-methylbenzenesulfonate (332 mg, 824.92 μmol, 34.13% yield) as a blue solid. MS (M+H) + =403.2

[0217] Step 5. ((1r,4r)-4-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenethyl)piperazin-1-yl)cyclohexane Synthesis of tert-butyl hexylcarbamate (trans) (8)

[0218] At 20 ° C, DIPEA (639.68 mg, 4.95 mmol, 862.10 μL) and NaI (24.73 mg, 164.98 μmol) were added to a DMF (10 mL) solution of 4-((2,6-dioxopiperidin-3-yl)amino)phenethyl 4-methylbenzenesulfonate (332 mg, 824.92 μmol) and tert-butyl ((1r, 4r)-4-(piperazine-1-yl)cyclohexyl)carbamate (trans) (467.58 mg, 1.65 mmol). The mixture was stirred at 40 ° C for 12 hours. LCMS showed that 26% of 4-((2,6-dioxopiperidin-3-yl)amino)phenethyl 4-methylbenzenesulfonate remained, and 25% of the peak showed that it had the desired mass. The reaction mixture was diluted with H2O (40 mL) and extracted with EtOAc (20 mL × 3). The organic layer was washed with brine (15 mL x 3), dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by preparative TLC (SiO2, DCM:MeOH = 10:1) and repurified by reverse phase HPLC (column: Phenomenex luna C18 150*25mm*10um; mobile phase: [water (TFA)-ACN]; B%: 14%-44%, 9 minutes) and lyophilized to give tert-butyl ((1r,4r)-4-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenethyl)piperazin-1-yl)cyclohexyl)carbamate (trans) (220 mg, 332.96 μmol, 40.36% yield, 95% purity, TFA). MS (M+H) + =514.5

[0219] Step 6. 3-((4-(2-(4-((1r,4r)-4-aminocyclohexyl)piperazin-1-yl)ethyl)phenyl)amino)piperidin-1-yl)ethyl)phenyl)amino)piperidin-1-yl Synthesis of pyridine-2,6-dione (trans) (9)

[0220] To a solution of tert-butyl ((1r, 4r)-4-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenethyl)piperazine-1-yl)cyclohexyl)carbamate (trans) (220 mg, 428.29 μmol, TFA) in DCM (3 mL) was added TFA (460.50 mg, 4.04 mmol, 0.3 mL) at 20 ° C. The mixture was stirred at 20 ° C for 1 hour. LCMS showed that the starting material was completely consumed and that 45% of the peak had the expected mass. The reaction mixture was concentrated in vacuo to give 3-((4-(2-(4-((1r, 4r)-4-aminocyclohexyl)piperazine-1-yl)ethyl)phenyl)amino)piperidine-2,6-dione (trans) (220 mg, crude, TFA) as a dark green oil. MS (M+H) + =414.4

[0221] Step 7. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenethyl)piperazin-1-yl)cyclohexyl)-3-((1r,4R)-4-(4-((2,6-dioxopiperidin-3-yl)amino)phenethyl)piperazin-1-yl)cyclohexyl)- Synthesis of Anisamide (Trans) (Compound 4)

[0222] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (169.36 mg, 398.05 μmol) in DMF (4 mL) at 20° C. were added HATU (166.48 mg, 437.85 μmol) and DIPEA (308.67 mg, 2.39 mmol, 415 μmol). .99 μL), after stirring for 10 minutes, a solution of 3-((4-(2-(4-((1r,4r)-4-aminocyclohexyl)piperazin-1-yl)ethyl)phenyl)amino)piperidine-2,6-dione (trans) (210 mg, 398.05 μmol, TFA) in DMF (4 mL) and DIPEA (308.67 mg, 2.39 mmol, 415.99 μL) was added at 20 ° C. The reaction mixture was stirred at 20 ° C for 1 hour. LCMS showed that the starting material was completely consumed and 37% of the peak showed the expected mass. The reaction mixture was diluted with H2O (40 mL) and extracted with EtOAc (15 mL×3), and the organic layer was washed with brine (12 mL×3), dried over Na2SO4, filtered and concentrated in vacuo. The crude product was purified by preparative TLC (SiO 2 , DCM:MeOH=10:1), and the product was dissolved in a mixture solution (20 mL, ACN:H 2 O=1:3) and lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (trans) (82.6 mg, 96.38 μmol, 24.21% yield, 95.8% purity) as a white solid. MS (M+H) + =821.5

[0223] 1H NMR (400MHz, DMSO-d6) δ = 10.77 (s, 1H), 8.41 (d, J = 8.9Hz, 1H), 8.11-8.03 (m, 1H), 7.84 (s, 1H), 7.6 0(s,1H),7.50-7.44(m,2H),6.95(d,J=8.4Hz,2H),6.61(d,J=8.3Hz,2H),5.78-5.62(m,1H),4.41 -4.31(m,1H),4.31-4.21(m,2H),3.94(s,3H),3.79-3.68(m,1H),3.25(s,3H),2.82-2.68(m,4H), 2.65-2.52(m,9H),2.15-1.70(m,15H),1.69-1.58(m,3H),1.48-1.31(m,4H),0.76(t,J=7.4Hz,3H)

[0224] Example 5. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(2-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)ethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 5)

[0225]

[0226] Step 1. Synthesis of benzyl 4-((1r,4r)-4-aminocyclohexyl)piperazine-1-carboxylate (trans) (2)

[0227] To a solution of benzyl 4-((1r,4r)-4-((tert-butyloxycarbonyl)amino)cyclohexyl)piperazine-1-carboxylate (trans) (1 g, 2.39 mmol) in DCM (5 mL) was added TFA (1.69 g, 14.86 mmol, 1.1 mL) at 20°C, and the resulting mixture was stirred at 20°C for 1 hour. LCMS showed that starting material remained, and the desired mass was detected. At 20°C, TFA (1.37 g, 11.97 mmol, 886.63 μL) was added to the reaction mixture, and the resulting mixture was stirred at 20°C for 2 hours. LCMS showed that starting material remained, and a peak with the desired mass was shown. The reaction mixture was stirred at 20°C for 12 hours. LCMS showed that the starting material was completely consumed, and a main peak with the desired mass was shown. The reaction mixture was concentrated in vacuo to give benzyl 4-((1r,4r)-4-aminocyclohexyl)piperazine-1-carboxylate (trans) (1.03 g, crude, TFA) as a yellow oil. MS (M+H) + =318.2

[0228] Step 2. 4-((1R,4r)-4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrakis Synthesis of benzyl (4)-(2-hydrogen pteridin-2-yl)amino)-3-methoxybenzamido)cyclohexyl)piperazine-1-carboxylate (trans)

[0229] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (trans) (0.8 g, 1.88 mmol) in DMF (6 mL) was added HATU (786.41 mg, 2.07 mmol) and DIPEA (729.02 mg, 5.64 mmol, 982.51 μL) at 20° C. After stirring for 10 minutes, a solution of benzyl 4-((1r,4r)-4-aminocyclohexyl)piperazine-1-carboxylate (1.03 g, crude, TFA) in DMF (6 mL) and DIPEA (1.46 g, 11.28 mmol, 1.97 mL) was added at 20° C., and the resulting mixture was stirred at 20° C. for 1 hour. LCMS showed that all starting materials were completely consumed and 78% of the peak had the expected mass. The reaction mixture was diluted with H2O (20 mL) and extracted with EtOAc (20 mL × 3). The organic layer was washed with brine (20 mL × 3), dried over Na2SO4, filtered and concentrated. The product was purified by flash chromatography on silica gel (25 g The residue was purified on a silica gel flash column with a gradient of 0-100% EtOAc / petroleum ether to 0-15% DCM / MeOH at 200 mL / min to afford benzyl 4-((1R,4r)-4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)cyclohexyl)piperazine-1-carboxylate (trans) (1.2 g, 1.64 mmol, 87.17% yield, 99% purity) as an off-white solid. MS (M+H) + =725.4

[0230] Step 3. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of 3-methoxy-N-((1r,4R)-4-(piperazin-1-yl)cyclohexyl)benzamide (trans) (5)

[0231] A solution of benzyl 4-((1R,4r)-4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)cyclohexyl)piperazine-1-carboxylate (trans) (600.00 mg, 827.71 μmol) in TFA (7.68 g, 67.31 mmol, 5 mL) was stirred at 50° C. for 12 hours. LCMS showed complete consumption of the starting material and 84% of the peak was of the expected mass. The reaction mixture was concentrated in vacuo to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-((1r,4R)-4-(piperazin-1-yl)cyclohexyl)benzamide (trans) (583 mg, crude, TFA) as a brown oil. MS (M+H) + =591.4

[0232] Step 4. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1-(4-(2,2-dimethoxyethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (reverse Synthesis of formula (6)

[0233] To a solution of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-((1r,4R)-4-(piperazin-1-yl)cyclohexyl)benzamide (trans) (523.00 mg, crude, TFA) in DMF (10 mL) was added DIPEA (575.43 mg, 4.45 mmol, 775.52 μL) and 2-bromo-1,1-dimethoxy-ethane (224.51 mg, 1.33 mmol, 155.91 μL) at 20 ° C., and the resulting mixture was stirred at 100 ° C. for 12 hours. LCMS showed that 3% of the starting material remained, and 27% of the peak showed the expected mass. The reaction mixture was diluted with H2O (20 mL) and extracted with EtOAc (15 mL × 3). The organic layer was washed with brine (15 mL x 3), dried over Na2SO4, filtered and concentrated. The residue was purified on a silica gel flash column with a 0-100% EtOAc / petroleum ether gradient at 150 mL / min to afford 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(2,2-dimethoxyethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (trans) (283 mg, 416.87 μmol, 56.18% yield) as a yellow solid. MS (M+H) + =679.4

[0234] Step 5. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of (1r, 4R)-4-(4-(2-oxoethyl)piperazin-1-yl)cyclohexyl)benzamide (trans) (7) become

[0235] To a solution of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(2,2-dimethoxyethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (trans) (283 mg, 416.87 μmol) in HO (5 mL) at 20° C. was added HBr (1.49 g, 7.37 mmol, 1 mL, 40% purity), and the resulting mixture was stirred at 40° C. for 12 hours. LCMS showed 42% starting material remaining and 28% of the peaks showed the expected mass, and the reaction mixture was stirred at 40° C. for 12 hours. LCMS showed that the starting material was completely consumed and 91% of the peaks showed the expected mass. The reaction mixture was concentrated in vacuo to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-((1r,4R)-4-(4-(2-oxoethyl)piperazin-1-yl)cyclohexyl)benzamide (trans) (264 mg, crude) as a yellow oil. MS (M+H2O+H) + =651.3

[0236] Step 6. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(4-(2-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)ethyl)-N-((1r,4R)-4-(4-(2-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)ethyl)- Synthesis of 1-(2-methyl-1-piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (trans) (Compound 5)

[0237] To a solution of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-((1r,4R)-4-(4-(2-oxoethyl)piperazin-1-yl)cyclohexyl)benzamide (trans) (174 mg, 274.97 μmol) and 3-(4-amino-1-oxo-isoindolin-2-yl)piperidine-2,6-dione (71.29 mg, 274.97 μmol) in MeOH (5 mL) at 20°C was added TFA (31.35 mg, 274.97 μmol, 20.43 μL) followed by the slow addition of NaBH3CN (51.84 mg, 824.91 μmol) at 20°C and the resulting mixture was stirred at 20°C for 1 hour. The product of 1-H-oxo-2-nitropropene was added into the 4-nitropropene (2-nitropropene) and 1-nitropropene (2-nitropropene) ... The product was re-purified by preparative HPLC (column: Phenomenex luna C18150*40mm*15um; mobile phase: [water (TFA)-ACN]; B%: 15%-45%, 10 minutes) and lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(2-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)ethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (trans) (23.1 mg, 18.58 μmol, 6.76% yield, 98% purity, 3TFA) as a white solid. MS (M+H) + =876.4

[0238] 1H NMR (400MHz, DMSO-d6) δ = 11.02 (s, 1H), 9.04-8.69 (m, 1H), 8.27-8.20 (m, 1H), 8.05-7.97 (m, 1H), 7.78 (s, 1H), 7.55-7.48 (m, 2H), 7 .33(t,J=7.7Hz,1H),7.00(d,J=7.3Hz,1H),6.85(d,J=8.2Hz,1H),5.13(dd,J=5.1,13.4Hz,1H),4.43-4.38(m,1H),4.27-4.10(m,3 H),3.91(s,3H),3.81-3.76(m,1H),3.44-3.42(m,14H),3.23(s,3H),2.96-2.92(m,1H),2.66-2.58(m,2H),2.46-2.38(m,1H),2.31 -2.23(m,1H),2.13-2.02(m,3H),2.02-1.90(m,4H),1.88-1.78(m,3H),1.65-1.55(m,3H),1.54-1.36(m,5H),0.75(t,J=7.5Hz,3H)

[0239] Example 6. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 6)

[0240]

[0241] Step 1. 4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl)piperidin-3-yl Synthesis of tert-butyl pyridine-1-carboxylate (3)

[0242] To a solution of 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione (1 g, 3.86 mmol) and tert-butyl 4-formylpiperidine-1-carboxylate (904.88 mg, 4.24 mmol) in MeOH (20 mL) was added HOAc (115.81 mg, 1.93 mmol, 110.40 μL), TFA (87.96 mg, 771.43 μmol, 57.30 μL), and NaBH3CN (727.17 mg, 11.57 mmol). The mixture was stirred at 25°C for 16 hours. LCMS showed 45% of 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione remaining, several new peaks were observed on LCMS, and a peak with the desired mass (44%) was observed. At 0 ° C, the reaction mixture was quenched with saturated NaHCO3 aqueous solution (30 mL) and then extracted with EtOAc (50 mL × 2). The combined organic layer was washed with brine (30 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue, which was triturated with EtOAc for 2 hours at 25 ° C and then triturated with MeOH for 16 hours at 25 ° C to give tert-butyl 4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl)piperidine-1-carboxylate (780 mg, 1.25 mmol, 32.34% yield, 73% purity) as a white solid. MS (M+H-100) + =357.3

[0243] Step 2. 3-(1-oxo-4-((piperidin-4-ylmethyl)amino)isoindolin-2-yl)piperidine-2,6-dione (4) Synthesis

[0244] To a solution of tert-butyl 4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl)piperidine-1-carboxylate (780 mg, 1.25 mmol) in dioxane (2 mL) was added HCl / dioxane (4 M, 3.12 mL). The mixture was stirred at 20° C. for 2 hours. LCMS showed complete consumption of tert-butyl 4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl)piperidine-1-carboxylate and one peak with the desired mass (65%) was observed. The reaction mixture was concentrated under reduced pressure to remove the solvent. The residue was purified by preparative HPLC (column: YMC Triart C18150*25mm*5um; mobile phase: [water (HCl)-ACN]; B%: 4%-34%, 10 minutes) and then lyophilized to give 3-(1-oxo-4-((piperidin-4-ylmethyl)amino)isoindolin-2-yl)piperidine-2,6-dione (360 mg, 916.31 μmol, 73.47% yield, HCl) as a white solid. MS (M+H) + =357.1

[0245] Step 3. ((1r,4r)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino Synthesis of tert-butyl (1-methyl)piperidin-1-yl)cyclohexyl)carbamate (6)

[0246] To a solution of 3-(1-oxo-4-((piperidin-4-ylmethyl)amino)isoindolin-2-yl)piperidine-2,6-dione (340 mg, 865.41 μmol, HCl) and tert-butyl ((1s,4s)-4-iodocyclohexyl)carbamate (562.83 mg, 1.73 mmol) in ACN (3 mL) and DMF (3 mL) was added NaCO (550.35 mg, 5.19 mmol). The mixture was stirred at 80° C. for 16 hours. LCMS showed 38% of 3-(1-oxo-4-((piperidin-4-ylmethyl)amino)isoindolin-2-yl)piperidine-2,6-dione remaining, several new peaks were shown on LCMS, and a peak with the expected mass (28%) was shown. Then add tert-butyl ((1s, 4s)-4-iodocyclohexyl)carbamate (281.42 mg, 865.41 μmol). The mixture was stirred at 80 ° C for another 32 hours. LCMS showed 16% residual 3- (1-oxo-4- ((piperidin-4-ylmethyl) amino) isoindoline-2-yl) piperidine-2,6-dione and showed a peak with the desired mass (30%). The reaction mixture was quenched with water (10 mL) at 0 ° C and then extracted with EtOAc (50 mL × 2). The combined organic layers were washed with brine (15 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue, which was purified by preparative HPLC (column: Phenomenex luna C18 150*40mm*15um; mobile phase: [water(FA)-ACN]; gradient: 8%-38% B over 15 minutes) and then lyophilized to give tert-butyl ((1r,4r)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (60 mg, 105.11 μmol, 12.15% yield, 97% purity) as a white solid. MS (M+H) + =554.5

[0247] Step 4. 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)-1-oxoisothiazolinone Synthesis of (2-indoline-1,2-yl)piperidine-2,6-dione (7)

[0248] To a solution of tert-butyl ((1r,4r)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (40 mg, 72.24 μmol) in dioxane (0.2 mL) was added HCl / dioxane (4 M, 180.61 μL). The mixture was stirred at 20° C. for 0.5 h. LCMS showed complete consumption of the starting material and one major peak with the expected mass. The reaction mixture was concentrated under reduced pressure to remove the solvent to give 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)-1-oxoisoindolin-2-yl)piperidine-2,6-dione (35 mg, 71.42 μmol, 98.87% yield, HCl) as a white solid. MS (M+H) + =454.3

[0249] Step 5. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl) Synthesis of (1-piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 6)

[0250] To a solution of 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)-1-oxoisoindolin-2-yl)piperidine-2,6-dione (35 mg, 71.42 μmol, HCl) and (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (27.35 mg, 64.28 μmol) in DMF (2 mL) was added HATU (40.74 mg, 107.13 μmol) and DIPEA (46.15 mg, 357.12 μmol, 62.20 μL). The mixture was stirred at 20° C. for 16 hours. LCMS showed complete consumption of the starting material and one peak with the expected mass (60%) was shown. The reaction mixture was quenched with water (15 mL) at 0°C and then extracted with EtOAc (20 mL x 2). The combined organic layers were washed with brine (10 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue which was purified by preparative HPLC (column: Phenomenex luna C18 The product was purified by HPLC-MS / MS (150*25mm*10um; mobile phase: [water (TFA)-ACN]; gradient: 30%-60% B over 10 minutes) and then lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)amino)methyl)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (29.0 mg, 25.83 μmol, 36.16% yield, 97% purity, 2TFA) as a white solid. MS (M+H) + =861.5

[0251] 1H NMR (400MHz, DMSO-d6) δ = 11.02 (s, 1H), 9.01-8.83 (m, 1H), 8.22 (d, J = 8.1Hz, 1H), 8.13-7.95 (m, 1H), 7.78 (s, 1H), 7.60-7.42 (m, 2H), 7.30 (t, J = 7. 8Hz,1H),6.94(d,J=7.5Hz,1H),6.81(d,J=8.1Hz,1H),5.89-5.71(m,1H) ,5.13(dd,J=5.0,13.2Hz,1H),4.40-4.39(m,1H),4.27-4.18(m,2H),4.15 -4.08(m,1H),3.92(s,3H),3.83-3.74(m,2H),3.66-3.61(m,2H),3.23(s ,3H),3.10-3.08(m,2H),3.03-2.89(m,3H),2.69-2.62(m,1H),2.57-2.5 4(m,1H),2.30-2.26(m,1H),2.11-1.95(m,7H),1.94-1.84(m,4H),1.83- 1.70(m,3H),1.68-1.55(m,4H),1.52-1.35(m,5H),0.76(t,J=7.3Hz,3H).

[0252] Example 7. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)methyl)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 7)

[0253]

[0254] Step 1. Synthesis of (4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)methanol (3)

[0255] To a solution of 2,6-bis(benzyloxy)-3-bromopyridine (2 g, 5.40 mmol), (4-(hydroxymethyl)phenyl)boronic acid (902.93 mg, 5.94 mmol) in dioxane (20 mL) and H2O (2 mL) was added Pd(dppf)Cl2 (395.26 mg, 540.19 μmol) and K2CO3 (2.24 g, 16.21 mmol), and the mixture was stirred at 100 ° C. for 16 hours under N2 atmosphere. LCMS showed a main peak with the expected mass. The mixture was filtered and the filtrate was concentrated in vacuo. The product was purified by flash chromatography on silica gel (20 g The residue was purified by silica gel flash column (0-50% EtOAc / petroleum ether gradient @ 40 mL / min) to afford (4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)methanol (1.8 g, 4.53 mmol, 83.84% yield) as a yellow oil. MS (M+H) + =398.2.

[0256] Step 2. Synthesis of 3-(4-(hydroxymethyl)phenyl)piperidine-2,6-dione (4)

[0257] A mixture of (4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)methanol (1 g, 2.52 mmol) and Pd / C (200 mg, 2.52 mmol, 10% purity) in CF3CH2OH (10 mL) was degassed and purged with H2 three times, and then stirred at 30°C for 16 hours under an atmosphere of H2 (50 Psi). TLC (petroleum ether: EtOAc = 1:2) indicated that the starting material was completely consumed, and a major new spot with greater polarity was detected. The mixture was filtered, and the filter cake was washed with CF3CH2OH (100 mL). The filtrate was concentrated in vacuo. The product was purified by flash chromatography on silica gel (Biotage; 10 g The residue was purified by silica gel flash column (0-50% EtOAc / petroleum ether gradient @ 80 mL / min) to afford 3-(4-(hydroxymethyl)phenyl)piperidine-2,6-dione (300 mg, 1.37 mmol, 54.63% yield) as a white solid. MS (M+H) + =219.3.

[0258] Step 3. Synthesis of 4-(2,6-dioxopiperidin-3-yl)benzaldehyde (5)

[0259] To a solution of 3-(4-(hydroxymethyl)phenyl)piperidine-2,6-dione (100 mg, 458.19 μmol) in DCM (2 mL) was added MnO2 (199.17 mg, 2.29 mmol) and the mixture was stirred at 20 ° C for 16 hours. TLC (petroleum ether: EtOAc = 1: 2) indicated that the starting material was completely consumed and a major new spot was detected. The mixture was filtered and the filter cake was washed with DCM (20 mL). The filtrate was concentrated in vacuo to give 4-(2,6-dioxopiperidin-3-yl)benzaldehyde (50 mg, 230.18 μmol, 50.24% yield) as a yellow solid. MS (M+H) + =218.3.

[0260] Step 4. Benzyl (4-(4-(((tert-Butoxycarbonyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (11) Synthesis

[0261] At 20 ℃, to a solution of tert-butyl (piperidin-4-ylmethyl)carbamate (3g, 14.00mmol) in DCE (80mL) was added benzyl (4-oxocyclohexyl)carbamate (3.5g, 14.15mmol) and HOAc (840.66mg, 14.00mmol, 801.39μL). After stirring for 2 hours at 25 ℃, NaBH (OAc) 3 (11.87g, 56.00mmol) was then added, and the resulting mixture was stirred for 14 hours at 25 ℃. LCMS showed a main peak with the desired mass. The reaction mixture was quenched by adding NaHCO 3 (200mL) and extracted with EtOAc (200mL×3). The combined organic layer was washed with brine (500mL×2), dried over Na 2 SO 4, filtered and concentrated in vacuo. The product was purified by reverse phase HPLC (Column HPLC). 330 g Flash Column WelchUltimate XB_C 18 20-40 μm; 120A; Sample dissolution solvent, approximately 15.00 g sample dissolved in 20 mL of DMF; flow rate 100 mL / min; mobile phase MeCN / H2O; gradient B% 10-100% 50 min; % min; instrument TELEDYNE ISCOCombiFlashRf 150 ) The residue was purified by lyophilization of the eluate to give benzyl (4-(4-(((tert-butoxycarbonyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (2 g, 4.49 mmol, 32.06% yield) as a yellow solid. MS (M+H) + =446.3.

[0262] Step 5. ((1r,4r)-4-(4-(((tert-Butyloxycarbonyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamic acid Synthesis of benzyl ester (trans) (12)

[0263] At 25 ℃, to CH CN (15mL) solution of (4-(4-(((tert-butyloxycarbonyl)amino)methyl)piperidin-1-yl)cyclohexyl)benzylcarbamate (0.5g, 1.12mmol), (S)-5-oxopyrrolidine-2-carboxylic acid (75.00mg, 580.88μmol) was added. The mixture was stirred at 70 ℃ for 2 hours, and then the mixture was stirred at 25 ℃ for 16 hours. LCMS showed the main peak with the desired mass. The reaction mixture was filtered. The filter cake was diluted with EtOAc (30mL) and H O (15mL), and the mixture was adjusted to pH=8 with NaOH (1M, 0.5mL), and extracted with EtOAc (40mL×2). The combined organic layers were washed with brine (30 mL x 2), dried over anhydrous Na2SO4, filtered, and concentrated in vacuo to afford benzyl ((1r,4r)-4-(4-(((tert-butoxycarbonyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (180 mg, 403.96 μmol, 36.00% yield) as a white solid. MS (M+H) + =446.3.

[0264] Step 6. Benzyl ((1r,4r)-4-(4-(aminomethyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (6) Synthesis

[0265] To a solution of benzyl ((1r,4r)-4-(4-(((tert-butyloxycarbonyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (180 mg, 403.96 μmol) in dioxane (1 mL) was added HCl / dioxane (4 M, 1 mL) and the mixture was stirred at 20 ° C for 1 hour. LCMS showed a major peak with the desired mass. The mixture was concentrated in vacuo to give benzyl ((1r,4r)-4-(4-(aminomethyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (150 mg, crude, HCl salt) as a white solid. MS (M+H) + =346.2.

[0266] Step 7. ((1r,4r)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)methyl)piperidin-1-yl Synthesis of benzyl)cyclohexyl)carbamate (trans) (7)

[0267] At 20 ° C, to a solution of 4-(2,6-dioxopiperidin-3-yl)benzaldehyde (50 mg, 230.18 μmol), benzyl ((1r, 4r)-4-(4-(aminomethyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (87.92 mg, 230.18 μmol, HCl salt) in DCM (2 mL) was added NaOAc (18.88 mg, 230.18 μmol). After stirring for 0.5 hours, NaBH(OAc) (146.35 mg, 690.54 μmol) was added and the mixture was stirred at 20 ° C for 16 hours. LCMS showed a main peak with the expected mass. The mixture was diluted with water (10 mL) and extracted with EtOAc (10 mL×3). The combined organic layers were washed with saturated NaHCO (10 mL×2), dried over NaSO, filtered and concentrated in vacuo. The residue was purified by reverse phase HPLC (column: YMC Triart C18 150*25mm*5um; mobile phase: [water (HCl)-ACN]; gradient: 2%-32% B over 8 minutes). The eluate was lyophilized to give benzyl ((1r,4r)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (60 mg, 109.75 μmol, 47.68% yield) as a white solid. MS (M+H) + =547.4.

[0268] Step 8. 3-(4-((((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)methyl)benzene Synthesis of 2,6-piperidin-2,6-dione (trans) (8)

[0269] A mixture of benzyl ((1r,4r)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)methyl)piperidin-1-yl)cyclohexyl)carbamate (trans) (60 mg, 109.75 μmol) in TFA (1 mL) was stirred at 60 °C for 4 hours. LCMS showed a major peak with the desired mass. The mixture was concentrated in vacuo to give 3-(4-((((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)methyl)phenyl)piperidine-2,6-dione (trans) (57 mg, 108.24 μmol, 98.63% yield, TFA salt) as a brown oil. MS (M+H) + =413.3.

[0270] Step 9. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(4-(((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)methyl)piperidin-1-yl)cyclohexane Synthesis of 2-(4-amino-3-methoxybenzamide) (trans) (Compound 7)

[0271] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (40.40 mg, 94.95 μmol) in DMF (1 mL) was added HATU (54.15 mg, 142.43 μmol) and DIPEA (61.36 mg, 474.75 μmol, 82.69 μL) at 20° C. After stirring for 0.5 hours, 3-(4-((((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)methyl)amino)methyl)phenyl)piperidine-2,6-dione (trans) (50 mg, 94.95 μmol, TFA salt) was added and the resulting mixture was stirred at 20° C. for 16 hours. LCMS showed a major peak with the expected mass. The mixture was diluted with water (10 mL) and extracted with EtOAc (10 mL x 3). The combined organic layers were washed with brine (20 mL x 2), dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by reverse phase HPLC (column: Phenomenex luna C18 150*25 mm*10 um; mobile phase: [water (TFA)-ACN]; gradient: 22%-52% B over 10 minutes). The eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)methyl)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (trans) (42.4 mg, 37.62 μmol, 39.62% yield, 93% purity, 2TFA salt) as a white solid. MS (M+H) + =820.5.

[0272] 1H NMR (400MHz, DMSO-d6) δ = 10.87 (s, 1H), 9.48-9.22 (m, 1H), 9.00-8.78 (m, 2H), 8.31-8.18 (m, 1H), 8.04-7. 93(m,1H),7.79(s,1H),7.56-7.39(m,4H),7.36-7.25(m,2H),4.43-4.37(m,1H),4.23-4.14(m,3H),3.93 -3.88(m,4H),3.83-3.77(m,1H),3.56-3.47(m,2H),3.32-3.10(m,5H),3.07-2.82(m,4H),2.75-2.64(m, 1H),2.27-2.17(m,1H),2.11-1.74(m,14H),1.69-1.54(m,4H),1.52-1.36(m,6H),0.76(t,J=7.4Hz,3H).

[0273] Example 8. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 8)

[0274]

[0275] Step 1. Synthesis of tert-butyl (4-(2,6-bis(benzyloxy)pyridin-3-yl)benzyl)carbamate (3)

[0276] To a solution of tert-butyl (4-bromobenzyl)carbamate (450 mg, 1.57 mmol), 2,6-bis(benzyloxy)-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (656.22 mg, 1.57 mmol) in dioxane (5 mL) and H2O (0.5 mL) was added Pd(dppf)Cl2 (230.12 mg, 314.50 μmol), K2CO3 (651.99 mg, 4.72 mmol). Under an N2 atmosphere, the mixture was stirred at 100 ° C for 16 hours. LCMS showed a peak with the desired mass (53%). The mixture was filtered through a diatomaceous earth pad. The filtrate was concentrated in vacuo to give a residue. The product was purified by flash chromatography on silica gel (Biotage; 10 g The residue was purified on a silica gel flash column (0-20% EtOAc / petroleum ether gradient @ 80 mL / min) to afford tert-butyl (4-(2,6-bis(benzyloxy)pyridin-3-yl)benzyl)carbamate (600 mg, 1.12 mmol, 71.46% yield, 93% purity) as a yellow solid. MS (M+H) + =497.2.

[0277] Step 2. Synthesis of tert-butyl (4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (4)

[0278] A mixture of tert-butyl (4-(2,6-bis(benzyloxy)pyridin-3-yl)benzyl)carbamate (600 mg, 1.21 mmol) and Pd / C (100 mg, 10% purity) in CF3CH2OH (10 mL) was degassed and purged with H2 three times. Under an atmosphere of H2 (50 Psi), the mixture was stirred at 20 ° C for 16 hours. TLC (petroleum ether: EtOAc = 3: 1) indicated that the starting material was completely consumed, and a major new spot with lower polarity was detected. The mixture was diluted with CH3CH2OH (30 mL), filtered through a celite pad, and washed with CH3CH2OH (30 mL). The filtrate was concentrated in vacuo to give tert-butyl (4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (380 mg, 1.19 mmol, 98.79% yield) as a yellow oil. MS (M+H) + =319.4.

[0279] Step 3. Synthesis of 3-(4-(aminomethyl)phenyl)piperidine-2,6-dione (5)

[0280] To a solution of tert-butyl (4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (280 mg, 879.49 μmol) in dioxane (3 mL) was added HCl / dioxane (4 M, 2.80 mL) and the mixture was stirred at 20 ° C for 1 hour. TLC (petroleum ether: EtOAc = 3: 1) indicated that the starting material was completely consumed and a major new spot with lower polarity was detected. The mixture was concentrated in vacuo to give 3-(4-(aminomethyl)phenyl)piperidine-2,6-dione (220 mg, crude product, HCl) as a white solid. MS (M+H) + =219.3.

[0281] Step 4. Synthesis of benzyl ((1r,4r)-4-(4-oxopiperidin-1-yl)cyclohexyl)carbamate (6)

[0282] To a solution of benzyl ((1r, 4r)-4-aminocyclohexyl)carbamate (500 mg, 1.76 mmol, HCl) in MeOH (5 mL) was added 1,5-dichloropentane-3-one (272.18 mg, 1.76 mmol), NaHCO3 (737.47 mg, 8.78 mmol, 341.58 μL), and the mixture was stirred at 75 ° C for 16 hours. LCMS showed multiple peaks and the expected mass. TLC (DCM: MeOH = 10: 1) indicated that the starting material was completely consumed and a new spot was detected. The reaction mixture was diluted with H2O (10 mL) and extracted with EtOAc (10 mL × 3). The combined organic layers were washed with brine (20 mL × 2), dried over Na2SO4, and filtered. The filtrate was concentrated in vacuo to give a residue. The product was purified by flash chromatography on silica gel (Biotage; 10 g The residue was purified by silica gel flash column (50-100% EtOAc / petroleum ether to 10% MeOH / EtOAc gradient @ 80 mL / min) to afford benzyl ((1r,4r)-4-(4-oxopiperidin-1-yl)cyclohexyl)carbamate (400 mg, 1.21 mmol, 68.95% yield) as a yellow oil. MS (M+H) + =331.1.

[0283] Step 5. ((1r,4r)-4-(4-((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)piperidin-1-yl)cyclohexane Synthesis of benzyl)carbamate (7)

[0284] To a solution of 3-(4-(aminomethyl)phenyl)piperidine-2,6-dione (80 mg, crude, HCl) and benzyl ((1r,4r)-4-(4-oxopiperidin-1-yl)cyclohexyl)carbamate (103.78 mg, 314.08 μmol) in DCM (1 mL) was added TEA (158.91 mg, 1.57 mmol, 218.58 μL), and the mixture was stirred at 20° C. for 0.5 h. NaBH(OAc) (199.70 mg, 942.24 μmol) was added, and the mixture was stirred at 20° C. for 16 h. LCMS showed a major peak with the expected mass. The mixture was filtered, and the filter cake was washed twice with EtOAc (10 mL) and water (10 mL), and dried under vacuum to give benzyl ((1r,4r)-4-(4-((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)piperidin-1-yl)cyclohexyl)carbamate (150 mg, crude) as a white solid. MS (M+H) + =533.4.

[0285] Step 6. 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)amino)methyl)phenyl)piperidin- Synthesis of 2,6-diketone (8)

[0286] A mixture of benzyl ((1r,4r)-4-(4-((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)piperidin-1-yl)cyclohexyl)carbamate (100 mg, crude) in TFA (0.5 mL) was stirred at 60 °C for 4 hours. LCMS showed a major peak with the desired mass. The mixture was concentrated in vacuo to give 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)amino)methyl)phenyl)piperidine-2,6-dione (90 mg, crude, TFA) as a brown oil. MS (M+H) + =399.3.

[0287] Step 7. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(4-((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)piperidin-1-yl)cyclohexyl)-3-methyl Synthesis of oxybenzamide (Compound 8)

[0288] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (74.71 mg, 175.59 μmol) in DMF (2 mL) were added HATU (80.12 mg, 210.71 μmol) and DIPEA (68.08 mg, 526.76 μmol, 91.75 μL), and the mixture was stirred at 20° C. for 0.5 hour. 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)amino)methyl)phenyl)piperidine-2,6-dione (90 mg, crude, TFA) was added, and the mixture was stirred at 20° C. for 16 hours. LCMS showed a peak with the desired mass (47%). The mixture was diluted with water (10 mL) and extracted with EtOAc (10 mL×3). The combined organic layers were washed with brine (20 mL×2), dried over Na 2 SO 4 , and filtered. The filtrate was concentrated in vacuo to give a residue. The residue was purified by preparative HPLC (column: Phenomenex luna C18 150*25 mm*10 um; mobile phase: [water (TFA)-ACN]; gradient: 23%-53% B over 10 minutes) and further purified by preparative HPLC (column: Phenomenex Luna C18 150*25 mm*10 um; mobile phase: [water (TFA)-ACN]; gradient: 22%-52% B over 10 minutes). The eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (41.5 mg, 40.13 μmol, 22.86% yield, 98% purity, 2TFA) as a white solid. MS (M+H) + =806.5.

[0289] 1H NMR (400MHz, DMSO-d6) δ = 10.87 (s, 1H), 9.86-9.70 (m, 1H), 9.31-9.13 (m, 2H), 9.07-8.90 (m, 1H), 8.26 (d, J = 7.6Hz, 1H), 7.98 (d ,J=7.5Hz,1H),7.79(s,1H),7.56-7.46(m,4H),7.33(d,J=8.1Hz,2H),4.45-4.37(m,1H),4.26-4.17(m,3H),3.94-3.88(m,5H) ,3.62-3.57(m,3H),3.43-3.34(m,2H),3.25-3.20(m,4H),3.16-3.05(m,2H),2.76-2.64(m,1H),2.56-2.51(m,2H),2.41-2.31 (m,2H),2.28-2.18(m,1H),2.13-1.96(m,5H),1.94-1.74(m,7H),1.64-1.53(m,3H),1.50-1.42(m,3H),0.75(t,J=7.5Hz,3H).

[0290] Example 9. Synthesis of N-(1-(2-amino-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)piperazin-1-yl)propionyl)piperidin-4-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamide (Compound 9)

[0291]

[0292]

[0293] Step 1. (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of methyl)-3-methoxybenzoic acid (13)

[0294] 3 batches: A mixture of (R)-2-chloro-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (550 mg, 1.87 mmol), 4-amino-3-methoxybenzoic acid (374.27 mg, 2.24 mmol) and HCl (12 M, 550.00 μL) in EtOH (2 mL) and H O (8 mL) was stirred at 105° C. for 12 hours. LCMS showed complete consumption of (R)-2-chloro-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one. The mixture of the three batches was concentrated in vacuo to give a mixture of (R)-ethyl 4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoate and (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (2.5 g) as a brown gum. To a solution of the brown gum (2.5 g) in MeOH (20 mL) and THF (20 mL) was added NaOH (2 M, 20 mL), and the mixture was stirred at 25 ° C for 16 hours. LCMS showed that the starting material was completely consumed and showed 65% of the expected mass. The mixture was concentrated in vacuo to remove most of the solvent. The residue was triturated with H2O (30 mL) and EtOAc (30 mL) for 10 min, the suspension was filtered, and the filter cake was washed with H2O (30 mL) and EtOAc (30 mL), the filter cake was diluted with EtOH (30 mL) and HCl solution (20 mL), and the mixture was concentrated in vacuo at 70°C. The residue was triturated with a mixture (EtOAc:EtOH:DMF=4:2:1, 7 mL) for 30 min, the suspension was filtered, and the filter cake was washed with EtOAc (20 mL). The mixture was triturated again with a mixture (EtOAc:EtOH:DMF=4:2:1, 10 mL) for 30 minutes, the suspension was filtered, and the filter cake was washed with a mixture (EtOAc:EtOH:DMF=4:2:1, 3 mL). The filter cake was collected and dried to give (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (950 mg, 2.23 mmol, 78.51% yield) as a gray solid. MS (M+H) + =426.2.

[0295] 1H NMR (400MHz, DMSO-d6) δ=13.31-12.55(m,1H),9.94-9.42(m,1H),7.98(d,J=8.1Hz,1H),7.91(s,1H),7.72-7.47(m,2H),4.47(dd,J=3.2,6. 4Hz,1H),4.26-4.15(m,1H),3.90(s,3H),3.30-3.17(m,3H),2.02-1.8 6(m,3H),1.85-1.70(m,3H),1.61-1.38(m,4H),0.75(t,J=7.4Hz,3H).

[0296] Step 2. (R)-4-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl) Synthesis of tert-butyl (amino)-3-methoxybenzamido)piperidine-1-carboxylate (15)

[0297] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (400 mg, 940.12 μmol) in DMF (5 mL) were added HATU (428.95 mg, 1.13 mmol) and DIPEA (364.51 mg, 2.82 mmol), and the mixture was stirred at 25° C. for 15 min. Then, tert-butyl 4-aminopiperidine-1-carboxylate (188.28 mg, 940.12 μmol) was added, and the resulting mixture was stirred at 25° C. for 1 hour. LCMS showed that (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid was completely consumed and showed 75% of the expected mass. The mixture was treated with AcOH to adjust the pH to 6-7, and the resulting mixture was diluted with H2O (50 mL) and extracted with EtOAc (50 mL×3). The combined organic layers were washed with brine (100 mL×3), dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by preparative TLC (SiO , petroleum ether: EtOAc = 1:2) to give (R)-tert-butyl 4-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)piperidine-1-carboxylate (375 mg, 617.04 μmol, 65.63% yield) as an off-white solid. MS (M+H) + =608.3.

[0298] Step 3. (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(piperidin-4-yl)-3-methoxy-N-(piperidin-4-yl)

[0299] Synthesis of benzamide (8)

[0300] To a solution of (R)-tert-butyl 4-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)piperidine-1-carboxylate (400 mg, 658.17 μmol) in DCM (10 mL) was added HCl / dioxane (4 M, 10 mL) and the mixture was stirred at 25 ° C for 1 hour. LCMS showed that the starting material was completely consumed and showed 89% of the expected mass. The reaction mixture was concentrated in vacuo to give (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-(piperidin-4-yl)benzamide (395 mg, HCl salt) as an off-white solid. MS (M+H) + =508.2.

[0301] Step 4. Benzyl 4-(2-((tert-Butyloxycarbonyl)amino)-3-methoxy-3-oxopropyl)piperazine-1-carboxylate (3) Synthesis

[0302] By 2-((tert-butoxycarbonyl) amino)-3-iodopropionic acid methyl ester (2.5g, 7.60mmol), piperazine-1-benzyl formate (1.71g, 7.75mmol, 1.50mL) and Na cO (1.61g, 15.19mmol) mixture in acetone (50mL) stirred 12 hours at 25 ℃.LCMS shows that 2-((tert-butoxycarbonyl) amino)-3-iodopropionic acid methyl ester is consumed completely, and shows 33% expected mass.Suspension is filtered, and with EtOAc (50mL) washing filter cake, filtrate is concentrated in vacuo.By flash chromatography on silica gel (20g The residue was purified using a silica gel flash column (14-26% EtOAc / petroleum ether gradient @ 100 mL / min) to afford benzyl 4-(2-((tert-butoxycarbonyl)amino)-3-methoxy-3-oxopropyl)piperazine-1-carboxylate (1.07 g, 2.54 mmol, 33.42% yield) as a yellow oil. MS (M+H) + =422.2.

[0303] Step 5. Synthesis of 3-(4-((benzyloxy)carbonyl)piperazin-1-yl)-2-((tert-butoxycarbonyl)amino)propanoic acid (4) become

[0304] To a solution of benzyl 4-(2-((tert-butoxycarbonyl)amino)-3-methoxy-3-oxopropyl)piperazine-1-carboxylate (1.07 g, 2.54 mmol) in MeOH (5 mL) and THF (5 mL) was added NaOH (2 M, 5 mL) and the mixture was stirred at 25 ° C for 12 hours. LCMS showed that the starting material was completely consumed and showed 53% of the expected mass. The mixture was concentrated in vacuo to remove most of the organic solvent. At 0 ° C, the residue was treated with a mixture of AcOH (580 μL) in H2O (5 mL) to adjust pH = 5 to 6. The mixture was extracted with EtOAc (10 mL×2), and the combined organic layers were concentrated in vacuo to give 3-(4-((benzyloxy)carbonyl)piperazin-1-yl)-2-((tert-butoxycarbonyl)amino)propanoic acid (850 mg) as a brown oil, which was used directly. MS (M+H) + =408.2.

[0305] Step 6. Synthesis of 2-((tert-Butyloxycarbonyl)amino)-3-(piperazin-1-yl)propanoic acid (5)

[0306] To a solution of 3-(4-((benzyloxy)carbonyl)piperazin-1-yl)-2-((tert-butoxycarbonyl)amino)propanoic acid (850 mg, 2.09 mmol) in CF3CH2OH (15 mL) was added Pd / C (200 mg, 10% purity) under N2. The suspension was degassed in vacuo and purged with H2 several times. The mixture was stirred under H2 (15 Psi) at 25°C for 12 hours. LCMS showed that the starting material was completely consumed. The mixture was filtered, and the filter cake was washed with CF3CH2OH (50 mL), and the filtrate was concentrated in vacuo to give 2-((tert-butoxycarbonyl)amino)-3-(piperazin-1-yl)propanoic acid (590 mg, crude) as a light brown solid. MS (M+H) + =274.1.

[0307] Step 7. 2-((tert-Butyloxycarbonyl)amino)-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxopiperidin-3-yl)- Synthesis of (4-isoindolin-1-yl)piperazin-1-yl)propionic acid (7)

[0308] A mixture of 2-(2,6-dioxopiperidin-3-yl)-4-fluoroisoindoline-1,3-dione (600 mg, 2.17 mmol), 2-((tert-butoxycarbonyl)amino)-3-(piperazin-1-yl)propanoic acid (600.00 mg, 2.20 mmol) and DIPEA (890.40 mg, 6.89 mmol, 1.20 mL) in DMSO (10 mL) was stirred at 100 ° C for 12 hours. LCMS showed that 2-(2,6-dioxopiperidin-3-yl)-4-fluoroisoindoline-1,3-dione was completely consumed and showed 74% of the expected mass. AcOH was added to the mixture until pH = 7, and the resulting mixture was filtered. The filtrate was purified by preparative HPLC (column: Phenomenex lunaC18 150*40mm*15um; mobile phase: [water (FA)-ACN]; B%: 10%-40%, 15 minutes), and the eluate was freeze-dried to give 2-((tert-butoxycarbonyl)amino)-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)piperazin-1-yl)propanoic acid (460 mg, 868.68 μmol, 39.99% yield) as an orange solid. MS (M+H) + =530.2.

[0309] Step 8. (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridine- (2-amino)-3-methoxybenzamido)piperidin-1-yl)-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxopiperidin-1-yl)- Synthesis of tert-butyl (4-(2-(2-oxoisoindolin-1-yl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (9)

[0310] A solution of 2-((tert-butoxycarbonyl)amino)-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)piperazin-1-yl)propanoic acid (180 mg, 339.92 μmol), HATU (181.70 mg, 477.86 μmol) and DIPEA (285.05 mg, 2.21 mmol, 384.16 μL) in DMF (5 mL) was stirred at 25° C. for 15 minutes, and then (R)-4-((8-cyclopentyl-7 -ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-(piperidin-4-yl)benzamide (200 mg, 367.59 μmol, HCl salt) was added and the resulting mixture was stirred at 25 ° C for 2 hours. LCMS showed residual traces of 2-((tert-butoxycarbonyl)amino)-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)piperazin-1-yl)propanoic acid and 67% of the expected mass. The mixture was diluted with H2O (15 mL) and extracted with EtOAc (10 mL×3). The combined organic layers were washed with brine (15 mL×5), dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by preparative TLC (SiO 2 , DCM:MeOH=15:1, twice) to give tert-butyl (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)piperidin-1-yl)-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (320 mg, 313.99 μmol, 85.42% yield) as a yellow solid. MS (M+H) + =1019.4.

[0311] Step 9. N-(1-(2-amino-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindoline- 4-yl)piperazin-1-yl)propionyl)piperidin-4-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7, Synthesis of 8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamide (Compound 9)

[0312] To a solution of tert-butyl (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)piperidin-1-yl)-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (320 mg, 313.99 μmol) in DCM (5 mL) was added HCl / dioxane (4 M, 5 mL) and the mixture was stirred at 25 °C for 1 hour. LCMS showed complete consumption of the starting material and 75% of the expected mass. The mixture was concentrated in vacuo. The residue was diluted with DMF (2.5 mL) and the mixture was treated with DIPEA to adjust pH>7. The resulting mixture was purified by preparative HPLC (column: Waters Xbridge 150*25mm10um; mobile phase: [water(NH4HCO3)-ACN]; B%: 35%-65%, 10 minutes), and the eluate was freeze-dried to give N-(1-(2-amino-3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)piperazin-1-yl)propanoyl)piperidin-4-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamide (127.0 mg, 129.34 μmol, 41.19% yield, 93.6% purity) as a yellow solid. MS (M+H) + =919.5.

[0313] 1H NMR (400MHz, CD3OD) δ=8.54-8.42(m,1H),7.78(d,J=1.5Hz,1H),7.70-7.59(m,1H),7.52-7.42(m,2H),7.41-7 .25(m,2H),5.14-5.05(m,1H),4.59-4.42(m,2H),4.32-4.25(m,1H),4.25-4.04(m,3H),4.00(d,J=8.5Hz,3H) ,3.47-3.35(m,4H),3.35-3.33(m,3H),2.96-2.80(m,3H),2.80-2.70(m,4H),2.70-2.58(m,2H),2.58-2.46(m ,1H),2.24-2.10(m,3H),2.07-1.92(m,3H),1.92-1.78(m,5H),1.77-1.68(m,3H),1.67-1.42(m,2H),0.86(br t,J=7.4Hz,3H).

[0314] Example 10. Synthesis of N-(1-(2-amino-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzamide (Compound 10)

[0315]

[0316] Step 1. (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridine- (4-(2,6-dioxopiperidin-3-yl)amino)-3-(trifluoromethoxy)benzamido)piperidin-1-yl)-3-(4-(2,6-dioxopiperidin-3-yl) Synthesis of tert-butyl (phenyl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (3)

[0317] To a solution of 2-((tert-butoxycarbonyl)amino)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propanoic acid (200 mg, 342.22 μmol, 78.8% purity) in DMF (6 mL) was added EDCI (78.72 mg, 410.66 μmol) and HOBt (55.49 mg, 410.66 μmol), DIPEA (132.69 mg, 1.03 mmol, 178.82 μL) and (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(piperidin-4-yl)-3-(trifluoromethoxy)benzamide (204.67 mg, 342.22 μmol, HCl salt). The mixture was stirred at 25 ° C for 1 hour. LCMS showed about 60% of the desired mass. The reaction mixture was diluted with water (30 mL) and extracted with EtOAc (20 mL × 3). The combined organic layer was washed with saturated brine (50 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 12g The residue was purified on a silica gel flash column with a 0-40% petroleum ether:EtOAc / EtOH (v / v=5 / 1) gradient @ 80 mL / min as the eluent to afford tert-butyl (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzamido)piperidin-1-yl)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (180 mg, 169.23 μmol, 49.45% yield, 94.4% purity) as a yellow oil. MS (M+H) + =1004.5.

[0318] Step 2. N-(1-(2-amino-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propanoyl 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)- ... Synthesis of 3-(trifluoromethoxy)benzamide (Compound 10)

[0319] To a solution of tert-butyl (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzamido)piperidin-1-yl)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (180 mg, 179.26 μmol) in DCM (2 mL) at 0° C. was added TFA (3.08 g, 27.01 mmol, 2 mL). The mixture was stirred at 25° C. for 2 hours. LCMS showed approximately 72.7% of the desired mass. The mixture was concentrated under reduced pressure to give a residue. The residue was purified by preparative HPLC (column: Phenomenex luna C18 150×40 mm×15 μm; mobile phase: [water (TFA)-ACN]; B%: 15%-45%, 10 minutes) and then lyophilized to give N-(1-(2-amino-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzamide (56 mg, 54.46 μmol, 30.38% yield, 99% purity, TFA salt) as a white solid. MS (M+H) + =904.4.

[0320] 1 H NMR (400MHz, DMSO-d6) δ = 10.77 (d, J = 2.9Hz, 1H), 9.57-9.36 (m, 1H), 8.45 (dd, J = 7.6, 17.7Hz, 1H), 8.22-7 .97(m,3H),7.95-7.88(m,2H),7.79(d,J=2.1Hz,1H),7.10-7.02(m,2H),6.92(dd,J=4.8,8.5Hz,2H),4.7 2-4.62(m,1H),4.39-4.37(m,1H),4.10-4.07(m,2H),3.95-3.86(m,4H),3.75-3.70(m,1H),3.23-3.14(m ,6H),2.95-2.72(m,5H),2.66-2.57(m,6H),2.23-2.04(m,2H),1.95-1.72(m,8H),1.62-1.53(m,1H),1.46 -1.34(m,5H),0.78-0.70(m,3H).

[0321] Example 11. Synthesis of N-(1-(2-amino-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propionyl)piperidin-4-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamide (Compound 11)

[0322]

[0323] Step 1. (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridine- 2-amino)-3-methoxybenzamido)piperidin-1-yl)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidin-1-yl) Synthesis of tert-butyl (1-oxazine-1-yl)-1-oxopropan-2-yl)carbamate (3)

[0324] To a solution of 2-((tert-butoxycarbonyl)amino)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propanoic acid (200 mg, 342.22 μmol, 78.8% purity) in DMF (5 mL) was added EDCI (78.73 mg, 410.66 μmol), (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-(piperidin-4-yl)benzamide (186.20 mg, 342.22 μmol, HCl salt), DIPEA (132.69 mg, 1.03 mmol, 178.83 μL), and HOBt (55.49 mg, 410.66 μmol). The mixture was stirred at 25° C. for 2 hours. LCMS showed about 60% of the desired mass. The reaction mixture was diluted with water (30 mL) and extracted with EtOAc (20 mL × 3). The combined organic layer was washed with saturated brine (50 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue which was purified by flash chromatography on silica gel ( 12g Purification was performed on a silica gel flash column with a 0-50% petroleum ether:EtOAc / EtOH (v / v=5 / 1) gradient @ 80 mL / min as the eluent to afford tert-butyl (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)piperidin-1-yl)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (180 mg, 159.51 μmol, 46.61% yield, 84.2% purity) as a yellow solid. MS (M+H) + =950.4.

[0325] Step 2. N-(1-(2-amino-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propanoyl 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)- ... Synthesis of 3-methoxybenzamide (Compound 11)

[0326] To a solution of tert-butyl (1-(4-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)piperidin-1-yl)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (180 mg, 189.45 μmol) in DCM (2 mL) at 0° C. was added TFA (3.08 g, 27.01 mmol, 2 mL). The mixture was stirred at 25° C. for 1 hour. LCMS showed approximately 76% of the desired mass. The reaction mixture was concentrated under reduced pressure to give a residue. The results were analyzed by preparative HPLC (column: Phenomenex luna C18 150×40 mm×15 μm; mobile phase: [water (TFA)-ACN]; B%: 10%-40%, 10 minutes) and preparative HPLC (column: Waters Xbridge The residue was purified by HPLC (150 × 25 mm × 5 μm; mobile phase: [water (NH4HCO3)-ACN]; B%: 36%-66%, 10 minutes) and then lyophilized to give N-(1-(2-amino-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamide (61.4 mg, 71.08 μmol, 37.52% yield, 98.4% purity) as a white solid. MS (M+H) + =850.2.

[0327] 1H NMR (400MHz, DMSO-d6) δ=10.84-10.67(m,1H),8.41(d,J=5.3Hz,1H),8.13(d,J=4.5Hz,1H),7.84(s,1H),7.60(s,1H),7 .47(d,J=8.1Hz,2H),7.06-7.03(m,2H),6.89(d,J=8.6Hz,2H),4.48-4.32(m,2H),4.23(dd,J=3.4,7.5Hz,1H),4.12-4.0 0(m,2H),3.93(d,J=6.0Hz,4H),3.75-3.67(m,1H),3.24(s,3H),3.15-3.08(m,5H),2.75-2.56(m,6H),2.47-2.31(m,4H ),2.17-2.10(m,1H),2.00-1.96(m,2H),1.90-1.74(m,8H),1.72-1.48(m,5H),1.45-1.33(m,1H),0.76(t,J=7.4Hz,3H).

[0328] Example 12. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)methyl)amino)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 12)

[0329]

[0330] Step 1. Synthesis of benzyl ((1r,4r)-4-(4-oxopiperidin-1-yl)cyclohexyl)carbamate (3)

[0331] 1,5-dichloropentane-3-one (108.87 mg, 702.29 μmol) and NaHCO3 (294.99 mg, 3.51 mmol, 136.63 μL) were added to a solution of benzyl ((1r, 4r)-4-aminocyclohexyl)carbamate (200 mg, 702.29 μmol, HCl) in MeOH (2 mL), and the mixture was stirred at 75 ° C for 16 hours. LCMS showed that the overlapping peaks had the expected mass. TLC (DCM: MeOH = 10: 1) showed that a new spot was detected. The reaction mixture was diluted with H2O (10 mL) and extracted with EtOAc (10 mL × 3). The combined organic layers were washed with brine (20 mL × 2), dried over Na2SO4, and filtered. The filtrate was concentrated in vacuo. The product was purified by flash chromatography on silica gel (Biotage; 10 g The residue was purified on a silica gel flash column (50-100% EtOAc / petroleum ether to 10% MeOH / EtOAc gradient @ 100 mL / min) to afford benzyl ((1r,4r)-4-(4-oxopiperidin-1-yl)cyclohexyl)carbamate (140 mg, 423.70 μmol, 60.33% yield) as a yellow solid. MS (M+H) + =331.1.

[0332] Step 2. ((1r,4r)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)methane Synthesis of benzyl)amino)piperidin-1-yl)cyclohexyl)carbamate (5)

[0333] A solution of benzyl ((1r, 4r)-4-(4-oxopiperidin-1-yl)cyclohexyl)carbamate (140 mg, 423.70 μmol), 3-(4-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione (115.79 mg, 423.70 μmol) and TEA (128.62 mg, 1.27 mmol, 176.92 μL) in DCM (2 mL) was stirred at 20 ° C for 0.5 hours, and NaBH (OAc) 3 (269.40 mg, 1.27 mmol) was added and the mixture was stirred at 20 ° C for 16 hours. LCMS showed a main peak with the expected mass. The mixture was filtered through a celite pad. The filtrate was quenched with NaHCO 3 (5 mL) and extracted with EtOAc (10 mL×5). The combined organic layers were dried over Na2SO4, filtered, and the filtrate was concentrated in vacuo to afford benzyl ((1r,4r)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)methyl)amino)piperidin-1-yl)cyclohexyl)carbamate (100 mg, crude) as a yellow solid. MS (M+H) + =588.3.

[0334] Step 3. 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)amino)methyl)-1-oxoisothiazolinone Synthesis of (2-indoline-1,2-dione)piperidine-2,6-dione (6)

[0335] A mixture of benzyl ((1r,4r)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)methyl)amino)piperidin-1-yl)cyclohexyl)carbamate (100 mg, 170.15 μmol) in TFA (1 mL) was stirred at 60 °C for 4 hours. LCMS showed a major peak with the desired mass. The mixture was concentrated in vacuo to give 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)amino)methyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione (90 mg, 158.56 μmol, 93.19% yield, TFA) as a brown oil. MS (M+H) +=454.2.

[0336] Step 4. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)methyl)amino) Synthesis of (1-piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 12)

[0337] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (67.47 mg, 158.56 μmol) in DMF (1 mL) were added HATU (72.35 mg, 190.28 μmol) and DIPEA (122.96 mg, 951.38 μmol, 165.71 μL), and the mixture was stirred at 20° C. for 0.5 hr. 3-(4-(((1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)amino)methyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione (90 mg, 158.56 μmol, TFA) was added, and the mixture was stirred at 20° C. for 16 hr. LCMS showed overlapping peaks with the desired mass (70%). The reaction mixture was diluted with H2O (5 mL) and extracted with EtOAc (10 mL×3). The combined organic layers were washed with brine (20 mL×2), dried over Na2SO4, and filtered. The filtrate was concentrated in vacuo. The crude product was purified by reverse phase HPLC (column: Waters Xbridge 150*25mm*5um; mobile phase: [water(NH4HCO3)-ACN]; B%: 37%-67%, 9 minutes) and lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)methyl)amino)piperidin-1-yl)cyclohexyl)-3-methoxybenzamide (18.1 mg, 19.13 μmol, 12.06% yield, 91% purity) as a white solid. MS (M+H) + =861.4.

[0338] 1H NMR (400MHz, DMSO-d6) δ = 10.99 (s, 1H), 8.43-8.38 (m, 1H), 8.01 (d, J = 7.7Hz, 1H), 7.84 (s, 1H), 7.62-7.57 (m, 3H), 7.49-7. 44(m,3H),5.17-5.09(m,1H),4.55-4.30(m,3H),4.27-4.20(m,1H),3.93(s,3H),3.85-3.78(m,2H),3.76-3.67(m,1H),3. 24(s,3H),3.01-2.86(m,1H),2.85-2.72(m,2H),2.65-2.56(m,4H),2.44-2.38(m,2H),2.28-2.24(m,1H),2.20-2.13(m,2 H),2.05-1.99(m,2H),1.92-1.85(m,4H),1.82-1.75(m,6H),1.67-1.58(m,3H),1.38-1.22(m,6H),0.76(t,J=7.4Hz,3H).

[0339] Example 13. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1-((1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)-3-methoxybenzamide (Compound 13)

[0340]

[0341] Step 1. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1-((1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl Synthesis of 3-methoxybenzamide (Compound 13)

[0342] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (61.29 mg, 144.05 μmol) in DMF (1 mL) at 20°C were added HATU (65.73 mg, 172.87 μmol) and DIPEA (18.62 mg, 144.05 μmol, 25.09 μL). After stirring for 10 minutes, a solution of 3-((4-(4-((4-(aminomethyl)piperidin-1-yl)methyl)piperidin-1-yl)phenyl)amino)piperidine-2,6-dione (114 mg, 216.08 μmol, TFA) in DMF (1 mL) and DIPEA (290.82 mg, 2.25 mmol, 391.94 μL) was added at 20 ° C., and the resulting mixture was stirred at 20 ° C for 16 hours. LCMS showed that the starting material was completely consumed and that 50% of the peak had the desired mass. The reaction mixture was diluted with H2O (20 mL) and extracted with EtOAc (10 mL × 3), the organic layer was washed with brine (10 mL × 3), dried over Na2SO4, filtered and concentrated in vacuo to give a crude product. The crude product was purified by preparative TLC (SiO 2 , DCM:MeOH=5:1), and the product was dissolved in a mixture solution (20 mL, ACN:H 2 O=1:3) and lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1-((1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)-3-methoxybenzamide (21 mg, 24.04 μmol, 16.45% yield, 94% purity) as an off-white solid. MS (M+H) + =821.2

[0343] 1H NMR (400MHz, DMSO-d6) δ = 10.75 (s, 1H), 8.42 (d, J = 8.8Hz, 2H), 7.84 (s, 1H), 7.61 (s, 1H), 7.52-7.48 (m, 2H), 6.79-6.72 (m ,2H),6.60(d,J=8.9Hz,2H),5.38(d,J=6.4Hz,1H),4.40-4.29(m,1H),4.24(dd,J=3.7,7.6Hz,1H),4.21-4.14(m,1H),3.9 4(s,3H),3.43-3.34(m,4H),3.27-3.14(m,7H),2.78-2.68(m,1H),2.62-2.57(m,1H),2.14-2.07(m,1H),2.06-1.95(m,2 H),1.94-1.86(m,3H),1.84-1.73(m,10H),1.68-1.57(m,4H),1.54-1.37(m,2H),1.34-1.21(m,4H),0.76(t,J=7.5Hz,3H)

[0344] Example 14. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-3-(trifluoromethoxy)benzamide (Compound 14)

[0345]

[0346] Step 1. (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of methyl 3-(trifluoromethoxy)benzoate (3)

[0347] To a solution of (R)-2-chloro-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (398.87 mg, 1.70 mmol) in DMF (8 mL) was added Pd(OAc)2 (38.08 mg, 169.62 μmol), BINAP (211.23 mg, 339.24 μmol) and Cs2CO3 (1.11 g, 3.39 mmol) and the reaction mixture was heated to 80°C under N2 atmosphere for 12 hours. LCMS showed a peak with the desired mass (57%). The reaction mixture was poured into 1N HCl solution to adjust pH to 7 and then extracted with EtOAc (50 mL×2). The combined organic layers were dried over Na2SO4 and filtered. The filtrate was concentrated in vacuo. The product was purified by flash chromatography on silica gel ( 40g The residue was purified on a silica gel flash column with a 0-30% EtOAc / petroleum ether gradient at 60 mL / min as the eluent to afford (R)-methyl 4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzoate (330 mg, 668.72 μmol, 39.43% yield) as a yellow oil. MS (M+H) + =494.3.

[0348] Step 2. (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of 3-(trifluoromethoxy)benzoic acid (4)

[0349] To a solution of (R)-methyl 4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzoate (330 mg, 668.72 μmol) in THF (1.5 mL) and MeOH (1.5 mL) was added a solution of NaOH (40.12 mg, 1.00 mmol) in HO (0.5 mL), and the resulting mixture was stirred at 15° C. for 16 hours. LCMS showed 12% of (R)-methyl 4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzoate remaining and a peak with the desired mass (59%). Concentrated HCl was added to the reaction mixture to adjust the pH to 6, and then concentrated in vacuo to give (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzoic acid (320 mg, 667.43 μmol) as a white solid, which was used in the next step without further purification. MS (M+H) + =480.2

[0350] Step 3. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl) Synthesis of 3-(trifluoromethoxy)benzamide (Compound 14)

[0351] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-(trifluoromethoxy)benzoic acid (97 mg, 168.75 μmol) in DMF (0.2 mL) was added HATU (133.22 mg, 350.36 μmol) and DIPEA (150.94 mg, 1.17 mmol, 203.42 μL). The mixture was stirred at 25° C. for 0.5 hours. 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (130 mg, 233.57 μmol, TFA) was then added, and the resulting mixture was stirred at 25° C. for 16 hours. LCMS showed that 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino)piperidine-2,6-dione was completely consumed and the expected mass was detected. At 25°C, the reaction mixture was diluted with H2O (10 mL) and then extracted with EtOAc (80 mL). The organic layer was washed with brine (10 mL), dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by flash chromatography on silica gel ( 20g The product was purified by silica gel flash column (eluent: 0-15% MeOH / EtOAc @ 50 mL / min), and then purified by preparative HPLC (column: Phenomenex luna C18 150*25 mm*10 um; mobile phase: [water (TFA)-ACN]; gradient: 23%-53% B over 9 minutes). The eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-3-(trifluoromethoxy)benzamide (53.8 mg, 45.62 μmol, 19.53% yield, 96% purity, 2TFA) as a purple solid. MS (M+H) + =904.4.

[0352] 1H NMR (400MHz, DMSO-d6) δ = 10.77 (s, 1H), 9.48-9.35 (m, 1H), 9.28-9.12 (m, 1H), 8.41 (br d,J=7.5Hz,1H),8.09(d,J=8.5Hz,1H),7.95-7.87(m,2H),7.79(s,1H),6.83(d,J=9.0Hz,2 H),6.65(d,J=8.9Hz,2H),4.41-4.34(m,2H),4.27-4.19(m,2H),4.14-4.06(m,3H),3.92(br d,J=3.5Hz,2H),3.57(br d,J=7.0Hz,2H),3.40(br d,J=6.3Hz,2H),3.27-3.16(m,6H),2.96-2.82(m,4H),2.80-2.71(m,1H),2.63-2.54( m,1H),2.13-2.03(m,1H),1.95-1.71(m,9H),1.56-1.36(m,6H),0.75(t,J=7.4Hz,3H).

[0353] Example 15. Synthesis of 3-(4-(4-(2-amino-3-(4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)piperidine-2,6-dione (Compound 15)

[0354]

[0355]

[0356] Step 1. (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of 3-methoxybenzoic acid (3)

[0357] At 20 ° C, to a solution of (R)-2-chloro-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (8 g, 27.14 mmol) in EtOH (100 mL) was added 4-amino-3-methoxybenzoic acid (4.4 g, 26.32 mmol) and HCl (12 M, 4.6 mL) in H2O (400 mL), and the mixture was stirred at 100 ° C for 16 hours. LCMS showed a peak with the expected mass (50%). The reaction mixture was stirred at 20 ° C for 1 hour, the mixture was filtered, and the filter cake was dried under reduced pressure to give (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (6 g, crude) as a light yellow solid. MS (M+H) + =426.2

[0358] Step 2. (R)-2-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl) Synthesis of tert-butyl (3-methoxybenzoyl)amino)hydrazine-1-carboxylate (4)

[0359] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (5 g, 11.75 mmol) in DMF (50 mL) was added HATU (6.75 g, 17.75 mmol), DIPEA (5.94 g, 45.93 mmol, 8 mL) and tert-butyl carbazate (1.8 g, 13.62 mmol) at 20 ° C. Under an N2 atmosphere, the mixture was stirred at 20 ° C. for 16 hours. LCMS showed a major peak with the expected mass. The reaction mixture was diluted with H2O (100 mL) and the mixture was extracted with EtOAc (150 mL×2). The combined organic layers were washed with brine (200 mL×3), dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was triturated with a solvent (EtOAc:MTBE=1:2; 90 mL) at 20° C. for 1 hour. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain (R)-tert-butyl 2-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoyl)hydrazine-1-carboxylate (5.2 g, 9.64 mmol, 82.00% yield) as a pale yellow solid. MS (M+H) + =540.3

[0360] Step 3. (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of 3-methoxybenzoylhydrazide (5)

[0361] To a solution of tert-butyl (R)-2-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoyl)hydrazine-1-carboxylate (2 g, 3.71 mmol) in DCM (15 mL) at 20 ° C was added TFA (12.28 g, 107.70 mmol, 8 mL). The mixture was stirred at 20 ° C for 2 hours. LCMS showed a major peak with the expected mass. The reaction mixture was concentrated under reduced pressure to give (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoyl)hydrazine-1-carboxylate (2 g, crude, TFA). MS (M+H) + =440.3

[0362] Step 4. (R)-N'-(2-chloroacetyl)-4-(8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8- Synthesis of tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid hydrazide (6)

[0363] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzohydrazide (2 g, crude, TFA) in DCM (40 mL) was added DIPEA (3.71 g, 28.71 mmol, 5 mL) and 2-chloroacetyl chloride (397.04 mg, 3.52 mmol, 280 μL) at 0 ° C. Under N2 atmosphere, the mixture was stirred at 20 ° C for 1 hour. LCMS showed a peak with the expected mass (56%). The reaction mixture was diluted with H2O (20 mL) and the mixture was extracted with DCM (50 mL×2). The combined organic layers were washed with brine (60 mL×2), dried over Na2SO4, filtered and concentrated under reduced pressure. The product was purified by flash chromatography on silica gel (80 g The residue was purified using a silica gel flash column (75-100% EtOAc / petroleum ether gradient @ 100 mL / min) to afford (R)-N'-(2-chloroacetyl)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzohydrazide (1.5 g, 2.91 mmol, 80.46% yield) as a pale yellow oil. MS (M+H) + =516.2

[0364] Step 5. (R)-2-((4-(5-(chloromethyl)-1,3,4-oxadiazol-2-yl)-2-methoxyphenyl)amino)-8- Synthesis of Cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (7)

[0365] Under N2 atmosphere, a solution of (R)-N'-(2-chloroacetyl)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzohydrazide (800 mg, 1.55 mmol) in POCl3 (13.16 g, 85.83 mmol, 8.00 mL) was stirred at 80 ° C for 32 hours. LCMS showed residual (R)-N'-(2-chloroacetyl)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzohydrazide (7%) and a peak with the desired mass (65%). The reaction mixture was concentrated under reduced pressure to remove POCl3. The crude product was then diluted with DCM (30 mL), and the organic layer was washed with NaHCO (30 mL x 2), dried over NaSO, filtered, and concentrated under reduced pressure to afford (R)-2-((4-(5-(chloromethyl)-1,3,4-oxadiazol-2-yl)-2-methoxyphenyl)amino)-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (770 mg, crude) as a yellow solid. MS (M+H) + =498.1

[0366] Step 6. (R)-4-(((5-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridine- Synthesis of tert-butyl 2-(2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidine-1-carboxylate (8) become

[0367] To a solution of (R)-2-((4-(5-(chloromethyl)-1,3,4-oxadiazol-2-yl)-2-methoxyphenyl)amino)-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (200 mg, 401.63 μmol) in DMF (3 mL) was added tert-butyl 4-aminopiperidine-1-carboxylate (90 mg, 449.38 μmol), DIPEA (222.59 mg, 1.72 mmol, 299.99 μL) and KI (60.00 mg, 361.45 μmol) at 20 ° C. Under N2 atmosphere, the mixture was stirred at 20 ° C for 16 hours. LCMS showed a peak with the expected mass. The reaction mixture was diluted with HO (10 mL) and the mixture was extracted with EtOAc (25 mL×2). The combined organic layers were washed with brine (20 mL x 3), dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified on a silica gel flash column (0-10% MeOH:EtOAc gradient, 100 mL / min) to afford (R)-tert-butyl 4-(((5-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidine-1-carboxylate (300 mg, crude) as a light yellow solid. MS (M+H) + =662.4

[0368] Step 7. (R)-8-Cyclopentyl-7-ethyl-2-((2-methoxy-4-(5-((piperidin-4-ylamino)methyl)-1, Synthesis of (3,4-oxadiazol-2-yl)phenyl)amino)-5-methyl-7,8-dihydropteridin-6(5H)-one (9)

[0369] To a solution of (R)-tert-butyl 4-(((5-(4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidine-1-carboxylate (0.3 g, 453.31 μmol) in dioxane (4 mL) was added HCl / dioxane (4 M, 4 mL) at 20°C. The mixture was stirred at 20°C for 2 hours. LCMS showed a major peak with the expected mass. The reaction mixture was concentrated under reduced pressure to give (R)-8-cyclopentyl-7-ethyl-2-((2-methoxy-4-(5-((piperidin-4-ylamino)methyl)-1,3,4-oxadiazol-2-yl)phenyl)amino)-5-methyl-7,8-dihydropteridin-6(5H)-one (270 mg, crude, HCl) as a pale yellow solid. MS (M+H) + =562.3

[0370] Step 8. (1-(4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydro (pteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidin-1-yl)-3-(4-(4- Synthesis of tert-butyl (2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (11)

[0371] To a solution of 2-((tert-butoxycarbonyl)amino)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)propanoic acid (120 mg, 260.57 μmol) in DMF (2 mL) at 20 °C were added EDCI (100.00 mg, 521.65 μmol), HOBt (40.00 mg, 296.03 μmol), DIPEA (296.80 mg, 2.30 mmol, 400.00 μL) and (R)-8-cyclopentyl-7-ethyl-2-((2-methoxy-4-(5-((piperidin-4-ylamino)methyl)-1,3,4-oxadiazol-2-yl)phenyl)amino)-5-methyl-7,8-dihydropteridin-6(5H)-one (200.00 mg, crude, HCl). Under N2 atmosphere, the mixture was stirred at 20 ℃ for 16 hours. LCMS showed a peak with the desired mass (58%). The reaction mixture was diluted with H2O (8mL), and the mixture was extracted with EtOAc (15mL×2). The combined organic layers were washed with brine (10mL×3), dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by preparative HPLC (column: Phenomene×luna C18 150×25mm×10um; mobile phase: [water (TFA)-ACN]; gradient: 20%-50% B, over 10 minutes; column temperature: 30 ℃) and by preparative HPLC (column: Waters Xbridge C18 150×50mm×10um; mobile phase: [water (NH4HCO3)-ACN]; gradient: 35%-65% B, over 10 minutes; column temperature: 30 ° C) and then purified to give tert-butyl (1-(4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidin-1-yl)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (210 mg, 209.13 μmol, 80.26% yield) as a light yellow solid. MS (M+H) + =1004.7

[0372] Step 9. 3-(4-(4-(2-amino-3-(4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo- (5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidin-2-yl) Synthesis of (1-piperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)piperidine-2,6-dione (Compound 15)

[0373] To a solution of tert-butyl (1-(4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidin-1-yl)-3-(4-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperazin-1-yl)-1-oxopropan-2-yl)carbamate (170 mg, 169.29 μmol) in DCM (5 mL) at 20 °C was added TFA (6.14 g, 53.85 mmol, 4 mL). The mixture was stirred at 20 °C for 2 hours. LCMS showed a major peak with the desired mass. The reaction mixture was concentrated under reduced pressure. The residue was lyophilized to give 3-(4-(4-(2-amino-3-(4-(((5-(4-((((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)piperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)piperidine-2,6-dione (132.9 mg, crude, 3TFA) as a light yellow solid. MS (M+H) + =904.6

[0374] 1 H NMR (400MHz, DMSO-d6) δ = 10.78 (s, 1H), 9.33-9.22 (m, 1H), 8.25-8.07 (m, 2H) ,7.86(s,1H),7.68-7.60(m,2H),7.12-7.03(m,2H),6.97-6.89(m,2H),4.81 -4.71(m,4H),4.61-4.42(m,5H),4.24-4.17(m,1H),4.03-3.92(m,4H),3.78-3.69(m,1H),3.62-3.51(m,1H),3.26-3.14(m ,7H),2.83-2.56(m,7H),2.49-2.42(m,1H),2.28-2.06(m,3H),1.98-1.74(m,6H),1.60-1.43(m,5H),0.77(t,J=7.4Hz,3H).

[0375] Example 16. Synthesis of 3-(4-(((1-((1r,4r)-4-(((5-(4-((((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)piperidin-4-yl)amino)methyl)phenyl)piperidine-2,6-dione (Compound 16)

[0376]

[0377] Step 1. (1-((1r,4r)-4-((tert-Butyloxycarbonyl)amino)cyclohexyl)piperidin-4-yl)(4-(2,6-dioxo Synthesis of Benzyl (3-piperidin-3-yl)benzyl)carbamate (2)

[0378] To a solution of tert-butyl ((1r, 4r)-4-(4-((4-(2,6-dioxopiperidin-3-yl)benzyl)amino)piperidin-1-yl)cyclohexyl)carbamate (500 mg, 1.00 mmol) in THF (5 mL) and H2O (5 mL) was added TEA (304.39 mg, 3.01 mmol, 418.69 μL). The reaction mixture was cooled to 0 ° C. CbzCl (342.10 mg, 2.01 mmol, 286.28 μL) was then slowly added and the resulting mixture was stirred at 25 ° C for 16 hours. LCMS showed a peak with the desired mass (about 25%). The reaction mixture was diluted with water (20 mL) and extracted with EtOAc (30 mL×3). The combined organic layer was washed with water (30 mL), dried over Na2SO4, and filtered. The filtrate was concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 20g The residue was purified on a silica gel flash column (30-40% MeOH / EtOAc gradient at 80 mL / min) to afford benzyl (1-((1r,4r)-4-((tert-butyloxycarbonyl)amino)cyclohexyl)piperidin-4-yl)(4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (410 mg, 647.93 μmol, 64.62% yield) as a yellow oil. MS (M+H) + =633.4.

[0379] Step 2. (1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)(4-(2,6-dioxopiperidin-3-yl)benzyl Synthesis of benzyl carbamate (3)

[0380] To the resulting solution of benzyl (1-((1r,4r)-4-((tert-butoxycarbonyl)amino)cyclohexyl)piperidin-4-yl)(4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (620 mg, 979.79 μmol) in dioxane (6 mL) was added HCl / dioxane (4 M, 6 mL). The mixture was stirred at 25 °C for 2 hours. LCMS showed that benzyl (1-((1r,4r)-4-((tert-butoxycarbonyl)amino)cyclohexyl)piperidin-4-yl)(4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate was completely consumed and showed one major peak with the expected mass. The reaction mixture was concentrated under reduced pressure to give benzyl (1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)(4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (600 mg, crude, HCl salt) as a yellow solid. MS (M+H) + =533.4.

[0381] Step 3. (1-((1r,4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6, 7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)piperidin Synthesis of Benzyl (4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (5)

[0382] To a solution of benzyl (1-((1r,4r)-4-aminocyclohexyl)piperidin-4-yl)(4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (300 mg, 527.12 μmol, HCl salt) and (R)-2-((4-(5-(chloromethyl)-1,3,4-oxadiazol-2-yl)-2-methoxyphenyl)amino)-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (262.49 mg, 527.12 μmol) in DMF (5 mL) was added KI (8.75 mg, 52.71 μmol) and DIPEA (204.37 mg, 1.58 mmol, 275.44 μL). The mixture was stirred at 40 °C for 20 h. LCMS showed a peak with the desired mass (approximately 54%). The residue was diluted with water (20 mL) and extracted with EtOAc (20 mL × 3). The combined organic layers were washed with brine (20 mL × 3), dried over Na2SO4 and filtered. The filtrate was concentrated under reduced pressure. The residue was purified by column chromatography via preparative TLC (SiO2, EtOAc: MeOH = 2: 1) to give (1-((1r, 4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)piperidin-4-yl)(4-(2,6-dioxopiperidin-3-yl)benzyl)carbamic acid benzyl ester (125 mg, 125.73 μmol, 23.85% yield) as a yellow solid. MS(M+H) + =994.6.

[0383] Step 4. 3-(4-(((1-((1r,4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo- (5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexane Synthesis of 4-(2-(4-(2-methyl-1-piperidin-4-yl)amino)methyl)phenyl)piperidine-2,6-dione (Compound 16)

[0384] To a solution of benzyl (1-((1r,4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)piperidin-4-yl)(4-(2,6-dioxopiperidin-3-yl)benzyl)carbamate (125 mg, 125.73 μmol) was added TFA (4.61 g, 40.39 mmol, 3 mL). The mixture was stirred at 60 °C for 16 hours. LCMS showed one major peak with the expected mass. The reaction mixture was concentrated under reduced pressure. The residue was purified by preparative HPLC (column: Phenomenex luna C18 150×40 mm×15 μm; mobile phase: [water(TFA)-ACN]; gradient: 10%-40% B over 10 min) and the eluent was lyophilized to give 3-(4-(((1-((1r,4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)piperidin-4-yl)amino)methyl)phenyl)piperidine-2,6-dione (113.3 mg, 88.31 μmol, 70.24% yield, 93.7% purity, 3TFA salt) as a white solid. MS(M+H) + =860.5.

[0385] 1H NMR (400MHz, CD3CN) δ = 10.19-10.07 (m, 1H), 8.84 (br s,1H),7.97(d,J=8.8Hz,1H),7.65-7.61(m,2H),7.49-7.44(m,3H),7.27(d,J=8.2Hz,2H),4.48(s,2H),4.33(dd,J =3.4,6.7Hz,1H),4.20-4.13(m,3H),3.93(s,3H),3.82(dd,J=5.3,11.3Hz,1H),3.60-3.54(m,2H),3.49-3.44(m,1 H),3.22(s,3H),3.18-3.16(m,1H),2.99-2.95(m,2H),2.66-2.59(m,4H),2.43-2.37(m,3H),2.34-2.28(m,3H),2. 26-2.22(m,2H),2.20-2.15(m,4H),1.87-1.76(m,4H),1.63-1.55(m,4H),1.53-1.40(m,5H),0.80(t,J=7.5Hz,3H).

[0386] Example 17. Synthesis of 3-(4-(4-((((1r,4r)-4-(((5-(4-((((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)amino)methyl)piperidin-1-yl)-3-fluorophenyl)piperidine-2,6-dione (Compound 17)

[0387]

[0388] Step 1. ((1r,4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8- (tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)carbamic acid Synthesis of tert-butyl ester (3)

[0389] To a solution of (R)-2-((4-(5-(chloromethyl)-1,3,4-oxadiazol-2-yl)-2-methoxyphenyl)amino)-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (200 mg, 401.63 μmol) in DMF (4 mL) at 20° C. was added tert-butyl ((1r,4r)-4-aminocyclohexyl)carbamate (120 mg, 478.54 μmol, HCl), DIPEA (267.12 mg, 2.07 mmol, 360.00 μL) and KI (60.00 mg, 361.44 μmol). The mixture was stirred at 20° C. under N atmosphere for 20 h. LCMS showed a peak with the desired mass (77%). The reaction mixture was diluted with H2O (10 mL) and the mixture was extracted with EtOAc (30 mL×2). The combined organic layers were washed with brine (20 mL×3), dried over Na2SO4, filtered and concentrated under reduced pressure. The product was purified by silica gel flash chromatography (Biotage; 10 g The residue was purified on a silica gel flash column with a 0-10% MeOH:EtOAc gradient at 100 mL / min to afford tert-butyl ((1r,4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)carbamate (300 mg, crude) as a light yellow solid. MS (M+H) + =676.4

[0390] Step 2. (R)-2-((4-(5-((((1r,4r)-4-aminocyclohexyl)amino)methyl)-1,3,4-oxadiazole-2-yl)- Synthesis of 7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (4)

[0391] To a solution of tert-butyl ((lr,4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)carbamate (300 mg, crude) in dioxane (5 mL) was added HCl / dioxane (4 M, 8 mL) at 20°C. The mixture was stirred at 20°C for 2 hours. LCMS showed a major peak with the expected mass. The reaction mixture was concentrated under reduced pressure to give (R)-2-((4-(5-((((1r,4r)-4-aminocyclohexyl)amino)methyl)-1,3,4-oxadiazol-2-yl)-2-methoxyphenyl)amino)-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (270 mg, crude, HCl) as a pale yellow solid. MS (M+H) + =576.3

[0392] Step 3. 3-(4-(4-((((1r,4r)-4-(((5-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo- (5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexane Synthesis of 2-(4-( ...amino-3-piperidin-1-yl)-3-fluorophenyl)piperidin-2,6-dione)) (Compound 17)

[0393] To a solution of 1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidine-4-carbaldehyde (120 mg, 376.95 μmol) in DCM (4 mL) at 20° C. were added (R)-2-((4-(5-((((1r,4r)-4-aminocyclohexyl)amino)methyl)-1,3,4-oxadiazol-2-yl)-2-methoxyphenyl)amino)-8-cyclopentyl-7-ethyl-5-methyl-7,8-dihydropteridin-6(5H)-one (210.00 mg, 343.05 μmol, HCl) and TEA (228.86 mg, 2.26 mmol, 314.80 μL) and the mixture was stirred at 20° C. for 1 h. Then, NaBH (OAc) 3 (300.00 mg, 1.42 mmol) was added to the mixture, and the resulting mixture was stirred at 20 ° C for 15 hours. LCMS showed a peak with the desired mass (43%). At 0 ° C, NaHCO 3 (saturated aqueous solution, 4 mL) was added to the reaction mixture to adjust the pH of the aqueous layer to 9-10, followed by extraction with DCM (15 mL × 2), and the combined organic layers were washed with brine (20 mL × 2), dried over Na 2 SO 4, filtered and concentrated under reduced pressure. The residue was purified by preparative HPLC (column: Phenomenex luna C18 150 × 25 mm × 10 um; mobile phase: [water (TFA)-ACN]; gradient: 16%-46% B over 10 minutes; column temperature: 30 ° C). The eluate was lyophilized to give 3-(4-(4-((((1r,4r)-4-(((5-(4-((((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)methyl)amino)cyclohexyl)amino)methyl)piperidin-1-yl)-3-fluorophenyl)piperidine-2,6-dione as a pale yellow solid (123.7 mg, 99.25 μmol, 26.33% yield, 97.9% purity, 3TFA). MS (M+H) + =878.6

[0394] 1H NMR (400MHz, DMSO-d6) δ=10.77(s,1H),9.96-9.78(m,1H),9.10-8.95(m,1H),8.59-8.47(m,1H),8.25(d,J=8.3 Hz,1H),7.86(s,1H),7.68-7.61(m,2H),7.05-6.94(m,3H),4.73(s,2H),4.46-4.38(m,1H),4.28-4.18(m,1H), 3.98(s,3H),3.85-3.76(m,1H),3.42-3.33(m,2H),3.25(s,2H),3.12-3.03(m,1H),2.99-2.83(m,2H),2.72-2. 62(m,2H),2.50-2.49(m,3H),2.30-2.13(m,5H),2.02-1.73(m,10H),1.66-1.33(m,11H),0.77(t,J=7.5Hz,3H).

[0395] Example 18. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino)cyclohexyl)-3-methoxybenzamide (Compound 18)

[0396]

[0397] Step 1. Synthesis of 1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidine-4-carboxaldehyde (2)

[0398] To a solution of 3-(3-fluoro-4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)piperidine-2,6-dione (2 g, 6.24 mmol) in DCM (50 mL) was added DMP (3.97 g, 9.36 mmol), and the mixture was stirred at 20 ° C for 2 hours. TLC (petroleum ether / EtOAc=1 / 1) showed that 3-(3-fluoro-4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)piperidine-2,6-dione was completely consumed and a new spot was formed. The mixture was filtered, and the filtrate was concentrated under reduced pressure to give 1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidine-4-carboxaldehyde (2 g, crude product) as a yellow oil. MS (M+H) + =319.4

[0399] Step 2. ((1r,4r)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methane Synthesis of benzyl)amino)cyclohexyl)carbamate (4)

[0400] To 1- (4- (2,6- dioxopiperidin-3-yl) -2- fluorophenyl) piperidine -4- carboxaldehyde (2g, 6.28mmol) and ((1r, 4r) -4- aminocyclohexyl) benzyl carbamate (1.56g, 6.28mmol) in DCM (20mL) solution, add AcOH (377.28mg, 6.28mmol, 359.66 μ L), and the mixture is stirred at 20 DEG C for 1 hour, then add NaBH (OAc) 3 (1.60g, 7.54mmol), and the resulting mixture is stirred at 20 DEG C for 12 hours. LCMS shows a peak (43%) with the desired mass. The reaction mixture is diluted with water (100mL) and extracted with DCM (50mL × 3). The combined organic layer is washed with saturated brine (200mL), dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by preparative HPLC (column: Phenomenexluna C18 150*40mm*15um; mobile phase: [water(TFA)-ACN]; gradient: 15%-45% B over 10 minutes) to give benzyl ((1r,4r)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino)cyclohexyl)carbamate (0.9 g, 1.57 mmol, 24.97% yield, 96% purity) as a yellow oil. MS (M+H) + =551.4

[0401] Step 3. 3-(4-(4-((((1r,4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)-3-fluorophenyl) Synthesis of piperidine-2,6-dione (5)

[0402] A solution of benzyl ((1r, 4r)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino)cyclohexyl)carbamate (450 mg, 817.20 μmol) in TFA (7.68 g, 67.31 mmol, 5 mL) was stirred at 40 ° C for 3 hours. LCMS showed a peak with the desired mass (79%). The mixture was concentrated under reduced pressure to give 3-(4-(4-((((1r, 4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)-3-fluorophenyl)piperidine-2,6-dione (0.4 g, 753.93 μmol, 92.26% yield, TFA) as a yellow oil. MS (M+H) + =417.3

[0403] Step 4. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino) Synthesis of cyclohexyl)-3-methoxybenzamide (Compound 18)

[0404] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (160.39 mg, 376.96 μmol) in DMF (5 mL) were added HATU (172.00 mg, 452.36 μmol) and DIPEA (194.88 mg, 1.51 mmol, 262.64 μL), and the mixture was stirred at 20° C. for 1 hr, 3-(4-(4-((((1r,4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)-3-fluorophenyl)piperidine-2,6-dione (0.2 g, 376.96 μmol, TFA) was added, and the mixture was stirred at 20° C. for 12 hr. LCMS showed a peak with the desired mass (60%). The reaction mixture was diluted with water (50 mL) and extracted with EtOAc (30 mL × 3). The combined organic layers were washed with saturated brine (100 mL), dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by preparative HPLC (column: Phenomenex lunaC18 150*40mm*15um; mobile phase: [water (TFA)-ACN]; gradient: 15%-45% B over 10 minutes), and the eluent was adjusted to pH = 9 with K2CO3 solid, and the resulting mixture was extracted with EtOAc (30 mL × 3). The combined organic layers were washed with saturated brine (100 mL), dried over anhydrous Na2SO4, filtered and concentrated, and the residue was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino)cyclohexyl)-3-methoxybenzamide (121.3 mg, 139.85 μmol, 37.10% yield, 95% purity) as a white solid. MS (M+H) + =824.5.

[0405] 1H NMR (400MHz, DMSO-d6) δ = 10.81 (s, 1H), 8.47-8.37 (m, 1H), 8.04 (br d,J=7.5Hz,1H),7.85(s,1H),7.60(s,1H),7.54-7.43(m,2H),7.08-6.89(m,3H),4.41-4.31(m,1H),4.24(br dd,J=3.4,7.3Hz,1H),3.94(s,3H),3.81-3.75(m,2H),3.25(s,3H),2.75-2.56(m,4H),2.52–2.45(m,4H),2.41-2. 33(m,1H),2.24-2.15(m,1H),2.06-1.74(m,15H),1.69-1.59(m,3H),1.50-1.25(m,5H),1.19-1.02(m,2H),0.77(br t,J=7.4Hz,3H).

[0406] Example 19. Synthesis of N-(4-(1-amino-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)piperidin-1-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamide (Compound 19)

[0407]

[0408] Step 1. (1-(1-((tert-Butyloxycarbonyl)amino)piperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidine-3-yl)- 1-[(2-fluorophenyl)piperazin-1-yl)ethyl)

[0409] Synthesis of benzyl carbamate (2)

[0410] To a solution of benzyl (1-(1-aminopiperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazine-1-yl)ethyl)carbamate (170 mg, 300.00 μmol) in THF (3 mL) was added TEA (212.50 mg, 2.10 mmol, 292.29 μL) and Boc O (196.42 mg, 900.00 μmol, 206.76 μL), and the mixture was stirred at 25 ° C for 12 hours. LCMS showed a desired mass of 38%. The mixture was diluted with water (10 mL) and extracted with EtOAc (10 mL × 3), and the combined organic layers were washed with water (10 mL), dried over Na SO and filtered. The filtrate was concentrated under reduced pressure. The residue was purified by preparative TLC (DCM:MeOH=20:1) to give benzyl (1-(1-((tert-butoxycarbonyl)amino)piperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (40 mg, 59.99 μmol, 20.00% yield) as a yellow solid. MS (M+H) + =667.4

[0411] Step 2. (1-(1-aminopiperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin- Synthesis of benzyl (1-oxazin-1-yl)ethyl)carbamate (3)

[0412] To a solution of benzyl (1-(1-((tert-butyloxycarbonyl)amino)piperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (40 mg, 59.99 μmol) in DCM (0.5 mL) was added TFA (122.80 mg, 1.08 mmol, 80 μL) and the mixture was stirred at 25 ° C for 1 hour. LCMS showed 82% of the expected mass. The mixture was concentrated under reduced pressure to give benzyl (1-(1-aminopiperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (40 mg, crude, TFA) as a yellow oil. MS (M+H) + =567.4

[0413] Step 3. (1-(1-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridine- 2-(4-(2,6-dioxopiperidin-3-yl)-2-fluorobenzene)amino)-3-methoxybenzamido)piperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorobenzene) Synthesis of benzyl)piperazin-1-yl)ethyl)carbamate (5)

[0414] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (30 mg, 70.51 μmol) and HATU (27 mg, 71.01 μmol) in DMF (1 mL) was added DIPEA (74.20 mg, 574.11 μmol, 0.1 mL), and the mixture was stirred at 25° C. for 15 minutes. A solution of benzyl (1-(1-aminopiperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (40 mg, crude, TFA) was then added at 0° C., and the mixture was stirred at 25° C. for 1 hour. LCMS showed 36% of the desired mass. The mixture was diluted with water (10 mL) and extracted with EtOAc (10 mL × 3), and the combined organic layers were washed with brine (10 mL), dried over Na2SO4 and filtered. The filtrate was concentrated under reduced pressure. The residue was purified by preparative TLC (DCM:MeOH=10:1) to give benzyl (1-(1-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)piperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (40 mg, 40.24 μmol, 68.48% yield, 98% purity) as a yellow solid. MS (M+H) + =974.5

[0415] Step 4. N-(4-(1-amino-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl) ethyl)piperidin-1-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl) Synthesis of (amino)-3-methoxybenzamide (Compound 19)

[0416]

[0266] A solution of benzyl (1-(1-(4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamido)piperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (120 mg, 123.19 μιηοΐ) in TFA (7.68 g, 67.31 mmol, 5 mL) was stirred at 60 °C for 4.5 hours. LCMS showed traces of starting material remaining and 52% of the desired mass. The mixture was concentrated under reduced pressure and then purified by preparative HPLC (column: Phenomenex Luna C18150*25mm*10um; mobile phase: [water(TFA)-ACN]; gradient: 17%-47% B over 10 minutes), and the eluate was lyophilized to give N-(4-(1-amino-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)piperidin-1-yl)-4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzamide (37.3 mg, 30.92 μmol, 25.10% yield, 98% purity, 3TFA) as a white solid. MS (M+H) + =840.5

[0417] 1 H NMR (400MHz, DMSO-d6)δ=10.82(br s,1H),9.51(br s,1H),9.24-9.01(m,1H),7.99-7.91(m,1H),7.79(br s,1H),7.55-7.38(m,2H),7.16-6.92(m,3H),4.46-4.38(m,1H),4.23-4.14 (m,1H),3.90(s,3H),3.85-3.79(m,1H),3.48-3.34(m,6H),3.22(s,3H),3. 18-3.02(m,6H),2.83-2.73(m,2H),2.70-2.60(m,1H),2.55-2.53(m,3H),2 .28-2.13(m,1H),2.05-1.69(m,10H),1.67-1.35(m,7H),0.82-0.67(m,3H).

[0418] Example 20. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(4-(2,6-dioxopiperidin-3-yl)phenethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (Compound 20)

[0419]

[0420] Step 1. Synthesis of 2-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)ethan-1-ol (3)

[0421] A mixture of 2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)ethan-1-ol (3 g, 12.09 mmol), 2,6-bis(benzyloxy)-3-bromopyridine (4.50 g, 12.15 mmol), CsCO (7.88 g, 24.18 mmol) and Pd(dppf)Cl (900.00 mg, 1.23 mmol) in dioxane (6 mL) and H O (1.2 mL) was degassed and purged with N 3 times, then stirred at 100 ° C. under a N atmosphere for 16 hours. LCMS showed a major peak with the desired mass. The reaction mixture was filtered. The filtrate was diluted with H O (80 mL) and then extracted with EtOAc (150 mL×2). The combined organic layers were washed with brine (100 mL x 2), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue which was purified by silica gel flash chromatography (Biotage; 40 g Purification was performed on a silica gel flash column (eluent: 15-25% EtOAc:petroleum ether gradient, 100 mL / min) to afford 2-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)ethan-1-ol (4.9 g, 11.91 mmol, 98.49% yield) as a pale yellow oil. MS (M+H) + =412.2

[0422] Step 2. Synthesis of 3-(4-(2-hydroxyethyl)phenyl)piperidine-2,6-dione (4)

[0423] Under N2 atmosphere, to a solution of 2-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)ethan-1-ol (1.9 g, 4.62 mmol) in CF3CH2OH (50 mL) was added Pd / C (4.91 g, 4.62 mmol, 10% purity), the suspension was degassed and purged with H2 three times, and then under H2 atmosphere (15 Psi), the mixture was stirred at 20 ° C for 32 hours. LCMS showed that 2-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)ethan-1-ol was completely consumed and showed a peak with the expected mass. The reaction mixture was filtered. The filtrate was concentrated under reduced pressure. The compound was triturated with MTBE (15 mL) at 20 ° C for 1 hour. The mixture was filtered. The filter cake was dried in vacuo to give 3-(4-(2-hydroxyethyl)phenyl)piperidine-2,6-dione (800 mg, 3.43 mmol, 74.28% yield) as a light yellow solid. MS (M+H) + =234.1

[0424] Step 3. Synthesis of 2-(4-(2,6-dioxopiperidin-3-yl)phenyl)acetaldehyde (5)

[0425] At 25 ° C, DMP (1.09 g, 2.57 mmol, 796.92 μL) was added to a solution of 3-(4-(2-hydroxyethyl)phenyl)piperidine-2,6-dione (500 mg, 2.14 mmol) in DCM (10 mL). The mixture was stirred at 25 ° C for 2 hours. LCMS showed a main peak with the desired mass. The reaction mixture was diluted with H2O (10 mL) at 20 ° C and then extracted with DCM (30 mL×2). The combined organic layers were washed with NaHCO3 (saturated aqueous solution, 30 mL×3), dried over Na2SO4, filtered and concentrated under reduced pressure to give 2-(4-(2,6-dioxopiperidin-3-yl)phenyl)acetaldehyde (490 mg, crude product) as a light yellow oil. MS (M+H) + =232.1

[0426] Step 4. ((1r,4r)-4-(4-(4-(2,6-dioxopiperidin-3-yl)phenethyl)piperazin-1-yl)cyclohexyl) Synthesis of tert-butyl carbamate (7)

[0427] At 20 ° C, to a solution of 2-(4-(2,6-dioxopiperidin-3-yl)phenyl)acetaldehyde (490 mg, 2.12 mmol) in DCM (20 mL) was added tert-butyl ((1r, 4r)-4-(piperazin-1-yl)cyclohexyl)carbamate (544.44 mg, 1.92 mmol) and TEA (1.29 g, 12.71 mmol, 1.77 mL), and the mixture was stirred at 20 ° C for 1 hour. NaBH (OAc) 3 (1.35 g, 6.36 mmol) was then added, and the resulting mixture was stirred at 20 ° C for another 15 hours. LCMS showed a peak with the desired mass (28%). The reaction mixture was adjusted to pH about 9 to 10 with NaHCO 3 (saturated aqueous solution, 20 mL) at 0 ° C, and then extracted with DCM (30 mL × 2). The combined organic layers were then washed with brine (30 mL × 2), dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was diluted with DMF (6 mL) and then filtered. The filter cake was concentrated under reduced pressure to give 350 mg of product. The filtrate was purified by preparative HPLC (column: Phenomenex luna C18 150 × 40 mm × 15 um; mobile phase: [water (TFA) -ACN]; gradient: 5% -35% B, over 10 minutes, column temperature: 30 ° C). The eluate was lyophilized to give 90 mg of product. Two batches were combined to give tert-butyl ((1r, 4r) -4- (4- (4- (2,6-dioxopiperidin-3-yl) phenethyl) piperazine-1-yl) cyclohexyl) carbamate (440 mg, 882.37 μmol, 41.64% yield) as a light yellow solid. MS (M+H) + =499.3

[0428] 1 H NMR (400MHz, DMSO-d6) δ = 10.81 (s, 1H), 7.22-7.05 (m, 4H), 6.71-6.63 (m, 1H), 3.85-3.77 (m, 1H), 3.18-3.07 (m, 1 H),2.72-2.59(m,3H),2.50-2.35(m,11H),2.19-2.00(m,3H),1.84-1.72(m,4H),1.37(s,9H),1.24-1.09(m,4H).

[0429] Step 5. 3-(4-(2-(4-((1r,4r)-4-aminocyclohexyl)piperazin-1-yl)ethyl)phenyl)piperidin-2,6- Synthesis of diketone (8)

[0430] To a solution of tert-butyl ((1r, 4r)-4-(4-(4-(2,6-dioxopiperidin-3-yl)phenethyl)piperazine-1-yl)cyclohexyl)carbamate (300 mg, 601.62 μmol) in dioxane (2 mL) was added HCl / dioxane (2M, 12 mL) at 20 ° C. The mixture was stirred at 20 ° C. for 2 hours. LCMS showed a main peak with the desired mass. The reaction mixture was concentrated under reduced pressure to give 3-(4-(2-(4-((1r, 4r)-4-aminocyclohexyl)piperazine-1-yl)ethyl)phenyl)piperidine-2,6-dione (260 mg, crude, HCl salt) as a white solid. MS (M+H) + =399.3

[0431] Step 6. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(4-(4-(2,6-dioxopiperidin-3-yl)phenethyl)piperazin-1-yl)cyclohexyl)-3-methoxy Synthesis of benzamide (Compound 20)

[0432] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (260 mg, 611.07 μmol) in DMF (5 mL) at 20° C. was added EDCI (200 mg, 1.04 mmol), HOBt (120 mg, 888.08 μmol), DIPEA (519.40 mg, 4.02 mmol, 700 μL) and 3-(4-(2-(4-((1r,4r)-4-aminocyclohexyl)piperazin-1-yl)ethyl)phenyl)piperidine-2,6-dione (260 mg, 597.70 μmol, HCl). The mixture was stirred at 20° C. under N atmosphere for 16 h. LCMS showed a major peak with the expected mass. The reaction mixture was diluted with H2O (15 mL) and then extracted with EtOAc (50 mL × 2). The combined organic layers were washed with brine (30 mL × 3), dried over Na2SO4, filtered and concentrated under reduced pressure. The compound was triturated with (EtOAc:MTBE=1:1; 40 mL) at 20 ° C for 1 hour. The mixture was filtered, and the filter cake was concentrated under reduced pressure and then lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(4-(2,6-dioxopiperidin-3-yl)phenethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (251.3 mg, 296.51 μmol, 48.52% yield, 95.1% purity) as a white solid. MS(M+H) + =806.6

[0433] 1H NMR(400MHz, DMSO-d6)δ=10.87-10.74(m,1H),8.47(s,1H),8.08-7.94(m,1H),7.85(s,1H),7.63-7.55(m, 1H),7.52-7.42(m,2H),7.23-7.14(m,2H),7.14-7.08(m,2H),4.40-4.31(m,1H),4.28-4.18(m,1H),3.94(s ,3H),3.84-3.68(m,2H),3.25(s,3H),2.74-2.62(m,3H),2.61-2.52(m,6H),2.47-2.36(m,4H),2.35-2.12( m,3H),2.07-1.98(m,2H),1.93-1.71(m,10H),1.67-1.55(m,3H),1.41-1.24(m,4H),0.77(t,J=7.2Hz,3H).

[0434] The filtrate was concentrated and then purified by preparative HPLC (column: Phenomene×luna C18 150×40 mm×15 μm; mobile phase: [water (TFA)-ACN]; gradient: 10%-40% B over 10 minutes, column temperature: 30° C.). The eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(4-(4-(2,6-dioxopiperidin-3-yl)phenethyl)piperazin-1-yl)cyclohexyl)-3-methoxybenzamide (114 mg, 106.61 μmol, 17.45% yield, 96.7% purity, 2TFA) as a white solid. MS (M+H) + =806.6

[0435] 1H NMR (400MHz, DMSO-d6) δ=0.83(s,1H),9.51-9.33(m,1H),8.30(d,J=7.7Hz,1H),7.85(d,J=8.3H z,1H),7.78(s,1H),7.59-7.50(m,2H),7.29-7.22(m,2H),7.22-7.16(m,2H),4.49-4.42(m,2H) ,4.16-4.12(m,2H),3.90(s,3H),3.86-3.82(m,2H),3.22-3.18(m,3H),2.97-2.90(m,2H),2.70 -2.60(m,1H),2.51-2.36(m,10H),2.19-1.77(m,12H),1.62-1.39(m,8H),0.75(t,J=7.5Hz,3H).

[0436] Example 21. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)-[1,4'-dipiperidinyl]-1'-yl)-3-methoxybenzamide (Compound 21)

[0437]

[0438] Step 1. tert-Butyl 4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidine-1-carboxylate (3) Synthesis

[0439] At 20 ° C, tert-butyl 4-formylpiperidine-1-carboxylate (960.00 mg, 4.50 mmol) and HOAc (314.70 mg, 5.24 mmol, 300 μL) were added to a solution of 3- (4-aminophenyl) piperidine-2,6-dione (800 mg, 3.92 mmol) in DCM (30 mL), and the mixture was stirred at 20 ° C for 1 hour. NaBH (OAc) 3 (2.40 g, 11.32 mmol) was then added, and the resulting mixture was stirred at 20 ° C for 15 hours. LCMS showed a main peak with the desired mass. The reaction mixture was adjusted to pH = 8 to 9 with NaHCO 3 (saturated aqueous solution) at 0 ° C, and then extracted with DCM (30 mL × 3). The combined organic layer was washed with brine (30 mL × 2), dried over Na 2 SO 4, filtered and concentrated under reduced pressure. The product was purified by preparative HPLC (column: Phenomenex luna C18 150×40 mm×15 um; mobile phase: [water (TFA)-ACN]; gradient: 15%-45% B over 10 minutes; column temperature: 30° C.) to give tert-butyl 4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidine-1-carboxylate (1.4 g, 3.49 mmol, 89.01% yield) as a pale yellow solid. MS (M+Na) + =424.2

[0440] Step 2. Synthesis of 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione (4)

[0441] To a solution of tert-butyl 4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)piperidine-1-carboxylate (1 g, 2.49 mmol) in dioxane (2 mL) was added HCl / dioxane (2 M, 20 mL) at 20 ° C., and the mixture was stirred at 20 ° C. for 2 hours. LCMS showed a major peak with the desired mass. The reaction mixture was concentrated under reduced pressure to give 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione (800 mg, crude, HCl salt) as a light yellow solid. MS (M+H) + =302.2

[0442] Step 3. Synthesis of 8-nitroso-1,4-dioxa-8-azaspiro[4.5]decane (7)

[0443] At 0 ° C, to 1,4-dioxa-8-azaspiro [4.5] decane (2g, 13.97mmol, 1.79mL) in H2O (20mL) solution was added NaNO2 (2.9g, 42.03mmol) in batches, and then HOAc (3.36g, 55.87mmol, 3.20mL) was added dropwise at 0 ° C, and the resulting mixture was stirred for another 16 hours at 20 ° C. LCMS showed a main peak with the desired mass. The reaction mixture was diluted with H2O (20mL) at 0 ° C, then adjusted to pH = 9 with NaHCO3 (saturated aqueous solution) at 0 ° C, and then extracted with EtOAc (50mL×3). The combined organic layers were washed with brine (60 mL x 2), dried over Na2SO4, filtered, and the filtrate was concentrated under reduced pressure to give 8-nitroso-1,4-dioxa-8-azaspiro[4.5]decane (2.4 g, crude) as a pale yellow solid. MS (M+H) + =173.0

[0444] Step 4. Synthesis of 1,4-dioxa-8-azaspiro[4.5]dec-8-amine (8)

[0445] To a solution of 8-nitroso-1,4-dioxa-8-azaspiro[4.5]decane (2 g, 11.62 mmol) in THF (20 mL) and H2O (10 mL) was added NH4Cl (3.20 g, 59.82 mmol) at 0°C under N2 atmosphere, followed by addition of Zn (4.10 g, 62.70 mmol) in portions at 0°C, and then the suspension was stirred at 20°C for 4 hours under N2 atmosphere. LCMS showed that the starting material was completely consumed and showed a main peak with the expected mass. The reaction mixture was filtered. The filter cake was washed with THF (50 mL). The filtrate of 1,4-dioxa-8-azaspiro[4.5]dec-8-amine (1.8 g, crude, light yellow oil) was used in the next step without further purification. MS (M+H) + =159.1

[0446] Step 5. Synthesis of tert-butyl (1,4-dioxa-8-azaspiro[4.5]dec-8-yl)carbamate (8A)

[0447] To a solution of 1,4-dioxa-8-azaspiro[4.5]dec-8-amine (1.8 g, 11.38 mmol) in THF (10 mL) and H2O (10 mL) was added Boc2O (7.60 g, 34.82 mmol, 8 mL) at 0°C and under N2 atmosphere, and then Na2CO3 (5 g, 47.17 mmol) was added portionwise to the mixture at 0°C. The mixture was then stirred at 20°C for 14 hours under N2 atmosphere. LCMS showed that 1,4-dioxa-8-azaspiro[4.5]dec-8-amine was completely consumed and showed a main peak with the expected mass. The reaction mixture was filtered. The filtrate was diluted with H2O (30 mL) and then extracted with EtOAc (80 mL×2). The combined organic layers were washed with brine (80 mL×2), dried over Na2SO4, filtered, and the filtrate was concentrated under reduced pressure. The results were analyzed by silica gel flash chromatography (Biotage; 20 g The residue was purified by silica gel flash column (eluent: 30-50% EtOAc:petroleum ether gradient, 100 mL / min) to afford tert-butyl (1,4-dioxa-8-azaspiro[4.5]dec-8-yl)carbamate (900 mg, 3.48 mmol, 30.62% yield) as a pale yellow solid. MS (M+H-56) + =203.1

[0448] Step 6. Synthesis of 1,4-dioxa-8-azaspiro[4.5]dec-8-amine (8)

[0449] To a solution of tert-butyl (1,4-dioxa-8-azaspiro[4.5]dec-8-yl)carbamate (600 mg, 2.32 mmol) in DCM (5 mL) was added TFA (4.61 g, 40.39 mmol, 3.00 mL) at 20 ° C. The mixture was stirred at 20 ° C. for 2 hours. LCMS showed a main peak with the desired mass. The reaction mixture was concentrated under reduced pressure to give 1,4-dioxa-8-azaspiro[4.5]dec-8-amine (600 mg, crude, TFA salt) as a light yellow oil. MS (M+H) + =159.1

[0450] Step 7. (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of 1,4-dioxa-8-azaspiro[4.5]dec-8-yl)-3-methoxy-N-(1,4-dioxa-8-azaspiro[4.5]dec-8-yl)benzamide (10)

[0451] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (600 mg, 1.41 mmol) in DMF (8 mL) was added EDCI (360.00 mg, 1.88 mmol), HOBt (240.00 mg, 1.78 mmol), DIPEA (1.11 g, 8.61 mmol, 1.50 mL) and 1,4-dioxa-8-azaspiro[4.5]dec-8-amine (600.00 mg, 2.20 mmol, TFA salt) at 20 ° C. Under an N atmosphere, the mixture was stirred at 20 ° C. for 16 hours. LCMS showed a peak with the desired mass (59%). The reaction mixture was diluted with H2O (30 mL) and then extracted with EtOAc (50 mL×2). The combined organic layers were washed with brine (50 mL x 3), dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (Biotage; 10 g The product was purified by silica gel flash column with a gradient of 60-100% EtOAc:petroleum ether at 80 mL / min as eluent, followed by preparative HPLC (column: Phenomenex luna C18 150×40 mm×15 μm; mobile phase: [water (TFA)-ACN]; gradient: 15%-45% B over 10 minutes, column temperature: 30°C). The eluate was lyophilized to give (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-(1,4-dioxa-8-azaspiro[4.5]dec-8-yl)benzamide (420 mg, 742.49 μmol, 52.65% yield) as a pale yellow solid. MS (M+H) + =566.3

[0452] Step 8. (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino Synthesis of 3-methoxy-N-(4-oxopiperidin-1-yl)benzamide (5)

[0453] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-(1,4-dioxa-8-azaspiro[4.5]dec-8-yl)benzamide (300 mg, 530.35 μmol) in HO (2 mL) and dioxane (2 mL) was added HCOOH (12 mL). The mixture was stirred at 20 ° C for 32 hours. LCMS showed a major peak with the desired mass. The reaction mixture was washed with EtOAc (20 mL). The aqueous phase was adjusted to pH 8-9 with Na2CO3 (saturated aqueous solution) at 0°C, then extracted with EtOAc (30 mL×3). The combined organic layers were washed with brine (30 mL×2), dried over Na2SO4, filtered, and the filtrate was concentrated under reduced pressure to obtain (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-(4-oxopiperidin-1-yl)benzamide (276 mg, crude) as a pale yellow oil. MS (M+H) + =522.3

[0454] Step 9. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1,4'-dipiperidin-1'-yl)-3-methyl-N-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)-[1,4'-dipiperidin-1'-yl)- Synthesis of oxybenzamide (Compound 21)

[0455] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxy-N-(4-oxopiperidin-1-yl)benzamide (240 mg, 460.11 μmol) in DCM (8 mL) at 20° C. was added 3-(4-((piperidin-4-ylmethyl)amino)phenyl)piperidine-2,6-dione (200 mg, 591.99 μmol, HCl salt) and TEA (436.20 mg, 4.31 mmol, 600.00 μL), and the mixture was stirred at 20° C. for 6 hours. NaBH(OAc) (420.00 mg, 1.98 mmol) was then added, and the resulting mixture was stirred at 20° C. for another 15 hours. LCMS showed a peak with the desired mass (25%). The reaction mixture was adjusted to pH 9-10 with NaHCO 3 (saturated aqueous solution) at 0° C., and then extracted with DCM (20 mL×2). The combined organic layers were washed with brine (20 mL×2), dried over Na 2 SO 4 , filtered, and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (Biotage; 10 g Silica gel flash column, eluting with a 0-10% EtOH:DCM gradient, 60 mL / min), and then purified by preparative HPLC (column: Phenomenex luna C18 150×25 mm×10 um; mobile phase: [water (TFA)-ACN]; gradient: 14%-44% B over 10 minutes, column temperature: 30°C). The eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(4-(((4-(2,6-dioxopiperidin-3-yl)phenyl)amino)methyl)-[1,4'-dipiperidin]-1'-yl)-3-methoxybenzamide (91.7 mg, 85.05 μmol, 18.48% yield, 96.0% purity, 2TFA) as a white solid. MS (M+H) + =807.6

[0456] 1 H NMR (400MHz, DMSO-d6) δ = 10.73 (s, 1H), 9.63-9.54 (m, 1H), 9.35-9.22 (m, 2H), 7.95-7.86 (m, 1H), 7.78 (s,1H),7.50-7.43(m,2H),6.95-6.89(m,2H),6.58-6.51(m,2H),4.45-4.42(m,1H),4.18-4.13(m,1H) ,3.89(s,4H),3.66-3.63(m,2H),3.56-3.54(m,1H),3.22(s,3H),3.17-3.08(m,3H),2.97-2.86(m,5H ),2.64-2.56(m,1H),2.10-1.97(m,6H),1.92-1.74(m,10H),1.54-1.38(m,6H),0.75(t,J=7.4Hz,3H).

[0457] Example 22. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[1,4'-dipiperidin]-4-yl)-3-methoxybenzamide (Compound 22)

[0458]

[0459] Step 1. Synthesis of tert-butyl 4-(((benzyloxy)carbonyl)amino)-[1,4'-dipiperidinyl]-1'-carboxylate (3)

[0460] To DCM (30mL) solution of tert-butyl 4-oxopiperidin-1-formate (2g, 10.04mmol), piperidin-4-yl benzylcarbamate (2.5g, 10.67mmol) and HOAc (629.40mg, 10.48mmol, 600 μL) are added. The mixture is stirred at 20°C for 2 hours. Then NaBH (OAc) is added at 20°C (4.67g, 22.02mmol), and the mixture of gained is stirred at 20°C for 14 hours. LCMS shows the peak (59%) with desired quality. The reaction mixture is diluted with H at 0°C o (10mL), NaHCO (saturated aqueous solution) is adjusted to pH=8-9 at 0°C, then extracted with DCM (30mL×3). The organic layer merged is washed with salt water (30mL×2), through Na sO dried, filtered, and the filtrate is concentrated under reduced pressure. The results were analyzed by reverse phase HPLC (ID.95mm×H 365mm Column Welch Ultimate XB_C 18 The residue was purified using a 1% FA (20-40 μm; 120A; mobile phase: MeCN / H₂O; gradient B: 30-50% over 45 min; % min; flow rate: 100 mL / min; 0.1% FA conditions). The eluate was lyophilized to afford tert-butyl 4-(((benzyloxy)carbonyl)amino)-[1,4'-dipiperidine]-1'-carboxylate (2.6 g, 6.23 mmol, 62.03% yield) as a pale yellow solid. MS (M+H) + =418.2

[0461] Step 2. Synthesis of benzyl [1,4'-dipiperidinyl]-4-ylcarbamate (4)

[0462] At 20 ° C, HCl / dioxane (2M, 10 mL) was added to a solution of tert-butyl 4-(((benzyloxy)carbonyl)amino)-[1,4'-dipiperidine]-1'-formate (1.0 g, 2.39 mmol) in dioxane (2 mL), and the mixture was stirred at 20 ° C for 2 hours. LCMS showed that tert-butyl 4-(((benzyloxy)carbonyl)amino)-[1,4'-dipiperidine]-1'-formate was completely consumed and showed a main peak with the desired mass. The reaction mixture was concentrated under reduced pressure to give benzyl [1,4'-dipiperidine]-4-ylcarbamate (800 mg, crude, HCl salt) as a light yellow solid. MS (M+H) + =318.2

[0463] Step 3. (1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[1,4'-dipiperidin-4-yl)carbamic acid Synthesis of benzyl ester (6)

[0464] At 20 ° C, to a solution of 2-(4-(2,6-dioxopiperidin-3-yl)phenyl)acetaldehyde (450 mg, 1.95 mmol) in DCM (25 mL) was added benzyl [1,4'-bipiperidin]-4-ylcarbamate (510 mg, 1.44 mmol, HCl salt) and TEA (1.65 g, 16.33 mmol, 2.27 mL), and the mixture was stirred at 20 ° C for 1 hour. NaBH (OAc) 3 (1.36 g, 6.43 mmol) was then added, and the resulting mixture was stirred at 20 ° C for 15 hours. LCMS showed a peak with the desired mass (24%). The reaction mixture was adjusted to pH = 9 to 10 with NaHCO 3 (saturated aqueous solution) at 0 ° C, and then extracted with DCM (40 mL × 2). The combined organic layer was washed with brine (40 mL × 2), dried over Na 2 SO 4, filtered and concentrated under reduced pressure. The residue was diluted with DMF (7 mL) and then filtered. The filter cake was dried in vacuo to give 150 mg of product. The filtrate was purified by preparative HPLC (column: Phenomenex luna C18 150×40 mm×15 um; mobile phase: [water (TFA)-ACN]; gradient: 0%-30% B, over 10 minutes, column temperature: 30°C, column temperature: 30°C). The eluate was lyophilized to give another 450 mg of product. Two batches were combined to give benzyl (1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[1,4'-dipiperidin]-4-yl)carbamate (600 mg, 1.13 mmol, 57.88% yield) as a light yellow solid. MS (M+H) + =533.3

[0465] Step 4. 3-(4-(2-(4-amino-[1,4'-bipiperidinyl]-1'-yl)ethyl)phenyl)piperidine-2,6-dione (7) Synthesis

[0466] A mixture of benzyl (1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[1,4'-bipiperidin]-4-yl)carbamate (560 mg, 1.05 mmol) in TFA (10 mL) was stirred at 60 ° C for 3 hours. LCMS showed that the starting material was completely consumed and showed a peak with the expected mass. The reaction mixture was concentrated under reduced pressure to give 3-(4-(2-(4-amino-[1,4'-bipiperidin]-1'-yl)ethyl)phenyl)piperidine-2,6-dione (540 mg, crude, TFA salt) as a light yellow oil. MS (M+H) + =399.3

[0467] Step 5. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[1,4'-dipiperidin-4-yl)-3-methoxybenzoyl Synthesis of amine (Compound 22)

[0468] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (400 mg, 940.12 μmol) in DMF (6 mL) at 20° C. was added EDCI (400 mg, 2.09 mmol), HOBt (200 mg, 1.48 mmol), DIPEA (742.00 mg, 5.74 mmol, 1 mL) and 3-(4-(2-(4-amino-[1,4′-dipiperidinyl]-1′-yl)ethyl)phenyl)piperidine-2,6-dione (540.00 mg, 1.05 mmol, TFA salt). The mixture was stirred at 20° C. under N atmosphere for 16 h. LCMS showed a peak with the desired mass (45%). The reaction mixture was diluted with H2O (15 mL) and then with EtOAc (40 mL x 2). The combined organic layers were washed with brine (30 mL x 3), dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by preparative HPLC (column: Phenomenex luna C18 150 x 40 mm x 15 μm; mobile phase: [water (TFA)-ACN]; gradient: 10%-40% B over 10 minutes, column temperature: 30°C). The eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[1,4'-dipiperidin]-4-yl)-3-methoxybenzamide (194.2 mg, 227.21 μmol, 24.17% yield, 94.3% purity, 2TFA) as a light yellow solid and an additional 90 mg of impure product which was repurified by preparative HPLC (column: Waters Xbridge C18 150×50 mm×10 um; mobile phase: [water(NH4HCO3)-ACN]; gradient: 25%-55% B over 10 minutes, column temperature: 30°C). The eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[1,4'-dipiperidin]-4-yl)-3-methoxybenzamide (46.7 mg, 57.19 μmol, 6.08% yield, 98.7% purity) as a pale yellow solid. MS (M+H) + =806.6

[0469] 1H NMR(400MHz, DMSO-d6)δ=10.86-10.77(m,1H),8.45-8.36(m,1H),8.09-8.01(m,1H),7.89-7.81( m,1H),7.62-7.56(m,1H),7.51-7.44(m,2H),7.21-7.15(m,2H),7.14-7.08(m,2H),4.41-4.32(m, 1H),4.28-4.19(m,1H),3.94(s,3H),3.84-3.71(m,2H),3.30-3.22(m,5H),2.99-2.85(m,4H),2. 74-2.58(m,4H),2.26-2.15(m,4H),2.04-1.90(m,5H),1.82-1.41(m,16H),0.77(t,J=7.5Hz,3H).

[0470] Example 23. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[4,4'-dipiperidin]-1-yl)-3-methoxybenzamide (Compound 23)

[0471]

[0472] Step 1. Synthesis of tert-butyl 1'-nitroso-[4,4'-dipiperidinyl]-1-carboxylate (2)

[0473] To a solution of [4,4'-bipiperidine]-1-tert-butyl formate (2g, 7.45mmol) in H2O (20mL) was added NaNO2 (1.54g, 22.36mmol) in batches at 0°C, followed by dropwise addition of HOAc (2.10g, 34.94mmol, 2mL) at 0°C, and the mixture was stirred at 20°C for 16 hours. LCMS showed a main peak with the desired mass. The reaction mixture was diluted with H2O (20mL) at 0°C, and NaHCO3 (saturated aqueous solution, 60mL) was added at 0°C to adjust to pH=9, followed by extraction with EtOAc (60mL×3). The combined organic layers were washed with brine 160mL (80mL×2), dried over Na2SO4, and filtered. The filtrate was concentrated under reduced pressure to give tert-butyl 1'-nitroso-[4,4'-bipiperidine]-1-formate (2.2g, crude product) as a light yellow oil. MS(M+H-56) + =242.1

[0474] 1H NMR (400MHz, DMSO-d6) δ = 4.87-4.80 (m, 1H), 4.69-4.58 (m, 1H), 4.01-3.86 (m, 2H), 3.73-3.64 (m, 1H), 2.79-2.53 (m, 3H), 1.9 6-1.89(m,1H),1.78-1.69(m,1H),1.68-1.59(m,2H),1.56-1.46(m,1H),1.39(s,9H),1.33-1.23(m,2H),1.09-0.91(m,3H).

[0475] Step 2. Synthesis of tert-butyl 1'-amino-[4,4'-dipiperidinyl]-1-carboxylate (3)

[0476] To a solution of tert-butyl 1'-nitroso-[4,4'-bipiperidine]-1-carboxylate (2.1 g, 7.06 mmol) in THF (20 mL) and H2O (10 mL) was added NH4Cl (2 g, 37.39 mmol) at 0°C and under N2 atmosphere, and then Zn (2.6 g, 39.76 mmol) was added portionwise to the mixture at 0°C, and the resulting mixture was stirred at 20°C for 3 hours under N2 atmosphere. LCMS showed a peak with the expected mass. The reaction mixture was filtered. The filter cake was washed with THF (50 mL). The filtrate of tert-butyl 1'-amino-[4,4'-bipiperidine]-1-carboxylate (2 g, crude product, light yellow oil) was used in the next step without further purification. MS (M+H) + =284.2

[0477] Step 3. Synthesis of tert-butyl 1'-(((benzyloxy)carbonyl)amino)-[4,4'-dipiperidine]-1-carboxylate (4)

[0478] At 0 ° C and N2 atmosphere, to a solution of 1'-amino-[4,4'-bipiperidine]-1-tert-butyl formate (2g, 7.06mmol) in THF (40mL) and H2O (20mL), Na2CO3 (4g, 37.74mmol) was added, and then CbzCl (4.80g, 28.16mmol, 4.02mL) was added dropwise at 0 ° C, and then the mixture was stirred at 20 ° C for 16 hours under N2 atmosphere. LCMS showed that 1'-amino-[4,4'-bipiperidine]-1-tert-butyl formate was completely consumed and showed a peak with the expected mass. The reaction mixture was filtered. The filtrate was diluted with H2O (30mL) and then extracted with EtOAc (60mL×2). The combined organic layer was washed with brine (50mL×3), dried over Na2SO4, and filtered. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (Biotage; 20 g The product was purified by silica gel flash column with a gradient of 25-33% EtOAc:petroleum ether, 80 mL / min, followed by preparative HPLC (column: Waters Xbridge C18 150×50 mm×10 μm; mobile phase: [water (NH4HCO3)-ACN]; gradient: 44%-74% B over 10 minutes, column temperature: 30°C). The eluate was lyophilized to give tert-butyl 1'-(((benzyloxy)carbonyl)amino)-[4,4'-dipiperidine]-1-carboxylate (1.8 g, 4.31 mmol, 61.09% yield) as a white solid. MS (M+H) + =418.2

[0479] Step 4. Synthesis of benzyl [4,4'-dipiperidinyl]-1-ylcarbamate (5)

[0480] To a solution of tert-butyl 1'-(((benzyloxy)carbonyl)amino)-[4,4'-dipiperidine]-1-carboxylate (1 g, 2.39 mmol) in dioxane (6 mL) was added HCl / dioxane (2 M, 10 mL) at 20 ° C. The mixture was stirred at 20 ° C. for 2 hours. LCMS showed a major peak with the desired mass. The reaction mixture was concentrated under reduced pressure to give benzyl [4,4'-dipiperidine]-1-ylcarbamate (820 mg, crude, HCl salt) as a light yellow solid. MS (M+H) + =318.2

[0481] Step 5. (1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[4,4'-dipiperidin-1-yl)carbamic acid Synthesis of benzyl ester (7)

[0482] At 20 ° C, to a solution of 2-(4-(2,6-dioxopiperidin-3-yl)phenyl)acetaldehyde (550 mg, 2.38 mmol) in DCM (25 mL) was added benzyl [4,4'-bipiperidin]-1-ylcarbamate (700 mg, 1.98 mmol, HCl salt) and TEA (2.04 g, 20.12 mmol, 2.8 mL), and the mixture was stirred at 20 ° C for 1 hour. NaBH (OAc) 3 (1.53 g, 7.21 mmol) was then added, and the resulting mixture was stirred at 20 ° C for 15 hours. LCMS showed a peak with the desired mass (56%). The reaction mixture was treated with NaHCO 3 (saturated aqueous solution) at 0 ° C to adjust to pH = 9 to 10, and then extracted with DCM (40 mL × 2). The combined organic layer was washed with brine (30 mL × 2), dried over Na 2 SO 4, filtered and concentrated under reduced pressure. The residue was diluted with DMF (6 mL) and filtered. The filter cake was dried under reduced pressure to give 550 mg of product. The filtrate was purified by preparative HPLC (column: Phenomenex luna C18 150×25 mm×10 um; mobile phase: [water (TFA)-ACN]; gradient: 16%-46% B, over 12 minutes). The eluate was lyophilized to give another 120 mg of product. Two batches were combined to give benzyl (1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[4,4'-dipiperidin]-1-yl)carbamate (670 mg, 1.26 mmol, 52.88% yield) as a light yellow solid. MS (M+H) + =533.3

[0483] Step 6. 3-(4-(2-(1'-amino-[4,4'-dipiperidinyl]-1-yl)ethyl)phenyl)piperidine-2,6-dione (8) Synthesis

[0484] A mixture of benzyl (1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[4,4'-bipiperidin]-1-yl)carbamate (150 mg, 281.60 μmol) in TFA (5 mL) was stirred at 60 ° C for 3 hours. LCMS showed that the starting material was completely consumed and showed a peak with the desired mass. The reaction mixture was concentrated under reduced pressure to give 3-(4-(2-(1'-amino-[4,4'-bipiperidin]-1-yl)ethyl)phenyl)piperidine-2,6-dione (144 mg, crude, TFA salt) as a light yellow oil. MS (M+H) + =399.3

[0485] Step 7. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[4,4'-dipiperidin-1-yl)-3-methoxybenzoyl)-N-(1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[4,4'-dipiperidin-1-yl)-3-methoxybenzoyl) Synthesis of amine (Compound 23)

[0486] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (110 mg, 258.53 μmol) in DMF (3 mL) at 20° C. was added EDCI (100 mg, 521.65 μmol), HOBt (60 mg, 444.04 μmol), DIPEA (296.80 mg, 2.30 mmol, 400 μL), and 3-(4-(2-(1′-amino-[4,4′-dipiperidin]-1-yl)ethyl)phenyl)piperidine-2,6-dione (144 mg, 280.94 μmol, TFA salt). The mixture was stirred at 20° C. under N atmosphere for 16 h. LCMS showed a peak with the desired mass (57%). The reaction mixture was diluted with H2O (5 mL) and then extracted with EtOAc (15 mL x 2). The combined organic layers were washed with brine (20 mL x 3), dried over Na2SO4, filtered, and concentrated under reduced pressure. The compound was purified by preparative HPLC (column: Phenomenex luna C18 150 x 25 mm x 10 μm; mobile phase: [water (TFA)-ACN]; gradient: 15%-45% B over 12 minutes, column temperature: 30°C). The eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1'-(4-(2,6-dioxopiperidin-3-yl)phenethyl)-[4,4'-dipiperidin]-1-yl)-3-methoxybenzamide (79.2 mg, 70.92 μmol, 27.43% yield, 92.6% purity, 2TFA) as a pale yellow solid. MS (M+H) + =806.6

[0487] 1H NMR (400MHz, DMSO-d6) δ = 10.84 (s, 1H), 9.94-9.76 (m, 1H), 9.66-9.32 (m, 2H), 7.92-7.83 (m, 1H) ,7.79(s,1H),7.57-7.45(m,2H),7.33-7.18(m,4H),4.48-4.38(m,1H),4.24-4.08(m,1H),3.98 -3.76(m,4H),3.67-3.36(m,2H),3.30-3.10(m,6H),3.02-2.79(m,5H),2.73-2.62(m,1H),2.49 -2.36(m,2H),2.26-2.10(m,1H),2.06-1.65(m,11H),1.63-1.06(m,11H),0.76(t,J=7.4Hz,3H).

[0488] Example 24. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-3-methoxybenzamide (Compound 24)

[0489]

[0490] Step 1. Synthesis of 3-((4-(piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (2)

[0491] To a solution of tert-butyl 4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazine-1-carboxylate (1 g, 2.57 mmol) in dioxane (20 mL) was added HCl / dioxane (2 M, 7.72 mL). The mixture was stirred at 25 ° C. for 8.5 hours. LCMS showed 3% of tert-butyl 4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazine-1-carboxylate remaining and 79% of the desired compound. The reaction mixture was concentrated under reduced pressure to give 3-((4-(piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (1.45 g, crude, HCl) as a blue solid. MS (M+H) + =289.2.

[0492] Step 2. (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-3-yl Synthesis of tert-butyl (4-pyridin-4-yl)carbamate (4)

[0493] To a DMF (20 mL) solution of 3-((4-(piperazine-1-yl)phenyl)amino)piperidine-2,6-dione (1.35 g, 4.16 mmol, HCl) and tert-butyl (1-(3-chloropropionyl)piperidin-4-yl)carbamate (1.09 g, 3.74 mmol) was added NaI (747.61 mg, 4.99 mmol) and DIPEA (1.61 g, 12.47 mmol, 2.17 mL). The mixture was stirred at 80 ° C for 16 hours. LCMS showed that 3-((4-(piperazine-1-yl)phenyl)amino)piperidine-2,6-dione was completely consumed and showed 48% of the desired compound. The residue was diluted with H2O (100 mL) and extracted with EtOAc (100 mL×3). The combined organic layer was washed with brine (200 mL), dried over Na2SO4, filtered and concentrated under reduced pressure. By silica gel flash chromatography (20g The residue was purified on a silica gel flash column (eluting with 100-50% EtOAc / MeOH at 45 mL / min) to afford tert-butyl (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)carbamate (0.65 g, 1.08 mmol, 25.94% yield, 90% purity) as a purple solid. MS (M+H) + =543.4.

[0494] Step 3. 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino) Synthesis of piperidine-2,6-dione (5)

[0495] To a solution of tert-butyl (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)carbamate (650 mg, 1.12 mmol, HCl) in dioxane (10 mL) was added HCl / dioxane (2 M, 10 mL). The mixture was stirred at 25 ° C for 2 hours. LCMS showed 63% of the desired compound. The reaction mixture was concentrated to give 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (790 mg, crude, HCl) as a blue solid. MS (M+H) + =443.3.

[0496] Step 4. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl) Synthesis of 3-methoxybenzamide (Compound 24)

[0497] To a solution of 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (790 mg, 1.65 mmol HCl) and (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (467.81 mg, 1.10 mmol) in DMF (10 mL) was added HATU (543.47 mg, 1.43 mmol) and DIPEA (710.50 mg, 5.50 mmol, 957.55 μL). The mixture was stirred at 25 ° C for 2 hours. LCMS showed 42% of the desired compound. The reaction mixture was poured into water (50 mL) and extracted with EtOAc (60 mL×3). The combined organic layers were washed with brine (200 mL), dried over Na2SO4 and concentrated to give the crude product. The product was purified by flash chromatography on silica gel ( 20g The residue was purified by silica gel flash column (eluting with 100-30% DCM:MeOH @ 50 mL / min) to give the crude product. The crude product was purified by preparative HPLC (column: Waters Xbridge C18 150×50 mm×10 um; mobile phase: [water(NH 4 HCO 3 )-ACN]; gradient: 25%-55% B over 10 minutes) and the eluent was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-(1-(3-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-3-methoxybenzamide (203.5 mg, 220.25 μmol, 20.03% yield, 92% purity) as a blue solid. MS (M+H) + =850.5

[0498] 1H NMR(400MHz,DMSO-d6)δ=10.75(br s,1H),8.42(d,J=8.9Hz,1H),8.11(d,J=7.9Hz,1H),7.84(s,1H),7.66-7.55(m,1H),7.52-7.37(m,2H),6.75(d, J=9.0Hz,2H),6.60(d,J=8.9Hz,2H),5.37(d,J=7.1Hz,1H),4.47-4.31(m,2H),4.28-4.13(m,2H),4.13-3.99(m, 1H),3.94(s,3H),3.44-3.36(m,2H),3.24(s,3H),3.17-3.08(m,1H),3.00-2.82(m,4H),2.80-2.63(m,2H),2.62 -2.52(m,8H),2.16-1.97(m,2H),1.96-1.71(m,9H),1.69-1.54(m,3H),1.54-1.28(m,2H),0.76(t,J=7.5Hz,3H)

[0499] Example 25. Synthesis of 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(((1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidin-4-yl)methyl)amino)cyclohexyl)-3-methoxybenzamide (Compound 25)

[0500]

[0501] Step 1. Synthesis of 1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidine-4-carbaldehyde (2)

[0502] To a solution of 3-(5-(4-(1,3-dioxolane-2-yl)piperidin-1-yl)pyridin-2-yl)piperidine-2,6-dione (0.5 g, 1.45 mmol) in dioxane (2 mL) and H2O (2 mL) was added FA (69.55 mg, 1.45 mmol, 6 mL), and the mixture was stirred at 25°C for 38 hours. The mixture was adjusted to pH = 8 with saturated Na2CO3 solution at 0°C and extracted with EtOAc (10 mL×3), and the combined organic layers were washed with water (20 mL), dried over Na2SO4 and filtered. The filtrate was concentrated under reduced pressure to give 1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidine-4-carbaldehyde (380 mg, crude) as a yellow oil. MS (M+H) + =302.2

[0503] Step 2. ((1r,4r)-4-(((1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidin-4-yl)methane Synthesis of tert-butyl (4-(4-amino)cyclohexyl)carbamate (trans) (3)

[0504] To a solution of 1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidine-4-carbaldehyde (380 mg, 1.26 mmol), tert-butyl ((1r, 4r)-4-aminocyclohexyl)carbamate (trans) (0.3 g, 1.40 mmol) in DCM (6 mL) and DMF (3 mL) was added TEA (261.72 mg, 2.59 mmol, 360 μL) and the mixture was stirred at 25 ° C for 15 minutes. NaBH (OAc) 3 (534.53 mg, 2.52 mmol) was added and the mixture was stirred at 25 ° C for 14 hours. LCMS showed that the expected mass was detected. The mixture was diluted with water (20 mL) and then extracted with EtOAc (10 mL×3), and the combined organic layers were washed with water (20 mL), dried over Na2SO4 and filtered. The filtrate was concentrated under reduced pressure. The product was purified by flash chromatography on silica gel (5 g The residue was purified on a silica gel flash column with a 15% MeOH / EtOAc gradient @ 50 mL / min as eluent to afford tert-butyl ((1r,4r)-4-(((1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidin-4-yl)methyl)amino)cyclohexyl)carbamate (trans) (250 mg, 480.34 μmol, 38.09% yield, 96% purity) as a yellow solid. MS (M+H) + =500.4

[0505] Step 3. 3-(5-(4-((((1r,4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)pyridin-2-yl) Synthesis of Piperidine-2,6-dione (trans) (4)

[0506] To a solution of tert-butyl ((1r, 4r)-4-(((1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidin-4-yl)methyl)amino)cyclohexyl)carbamate (trans) (250 mg, 500.36 μmol) in DCM (2.5 mL) was added HCl / dioxane (2M, 5 mL) and the mixture was stirred at 25 ° C for 1 hour. LCMS showed 93% of the expected mass. The mixture was concentrated under reduced pressure to give 3-(5-(4-((((1r, 4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)pyridin-2-yl)piperidine-2,6-dione (trans) (220 mg, crude, HCl) as a yellow solid. MS (M+H) + =400.3

[0507] Step 4. 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino 4-(((1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidin-4-yl)methyl)amino) Synthesis of (trans)-3-methoxybenzamide (cyclohexyl) (Compound 25)

[0508] To a solution of (R)-4-((8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-3-methoxybenzoic acid (210 mg, 493.56 μmol) and HATU (206.43 mg, 542.92 μmol) in DMF (3 mL) was added DIPEA (318.95 mg, 2.47 mmol, 429.85 μL), and the mixture was stirred at 25° C. for 15 minutes. 3-(5-(4-((((1r,4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)pyridin-2-yl)piperidine-2,6-dione (trans) (220 mg, 504.60 μmol, HCl) in DMF (3 mL) was added, and the mixture was stirred at 25° C. for 1 hour. The mixture was diluted with EtOAc (10 mL) and saturated NaHCO solution (10 mL), then extracted with EtOAc (10 mL × 3) and DCM (10 mL × 3), and the combined organic layers were washed with brine (30 mL × 2), dried over NaSO and filtered. The filtrate was concentrated under reduced pressure and then purified by preparative HPLC (column: Phenomenex luna C18150*25 mm*10 um; mobile phase: [water (TFA)-ACN]; gradient: 14%-44% B over 10 minutes), and the eluate was lyophilized. The product was purified by preparative HPLC (column: Waters Xbridge 150*25mm*5um; mobile phase: [water(NH4HCO3)-ACN]; gradient: 30%-50% B over 10 minutes), and the eluate was lyophilized to give 4-(((R)-8-cyclopentyl-7-ethyl-5-methyl-6-oxo-5,6,7,8-tetrahydropteridin-2-yl)amino)-N-((1r,4R)-4-(((1-(6-(2,6-dioxopiperidin-3-yl)pyridin-3-yl)piperidin-4-yl)methyl)amino)cyclohexyl)-3-methoxybenzamide (trans) (57.80 mg, 67.33 μmol, 13.64% yield, 94% purity) as a white solid. MS (M+H) + =807.7

[0509] 1H NMR(400MHz,DMSO-d6)δ=10.83-10.70(m,1H),8.40(d,J=8.8Hz,1H),8.20- 8.17(m,1H),8.02(d,J=8.1Hz,1H),7.84(s,1H),7.59(s,1H),7.49-7.44(m, 2H),7.31(dd,J=2.8,8.7Hz,1H),7.15(d,J=8.7Hz,1H),4.36(t,J=8.0Hz,1H ),4.23(dd,J=3.4,7.5Hz,1H),3.94(s,3H),3.87(dd,J=5.4,8.7Hz,1H),3.7 8-3.67(m,3H),3.24(s,3H),2.67(t,J=11.2Hz,2H),2.60-2.52(m,1H),2.48 -2.43(m,3H),2.37-2.28(m,1H),2.22-2.15(m,1H),2.13-2.07(m,1H),2.03 -1.99(m,1H),1.97-1.71(m,13H),1.68-1.56(m,3H),1.54-1.45(m,1H),1.4 3-1.31(m,2H),1.28-1.17(m,2H),1.14-1.03(m,2H),0.76(t,J=7.4Hz,3H).

[0510] SFC method details: "Column: Chiralpak AD-3 50×4.6 mm ID, 3 μm, mobile phase: phase A is CO2, and phase B is IPA+ACN (0.05% DEA); gradient elution: 60% IPA+ACN (0.05% DEA) / CO2, flow rate: 3 mL / min; detector: PDA, column temperature: 35°C; back pressure: 100 bar"

[0511] Example 26. 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine Synthesis of 1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)-2-fluorophenyl)piperazin-1-yl)propionyl)piperidin-4-yl)-3-methoxybenzamide (Compound 26)

[0512]

[0513] Step 1. Synthesis of 3-((3-fluoro-4-(piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (2)

[0514] To a solution of tert-butyl 4-(4-((2,6-dioxopiperidin-3-yl)amino)-2-fluorophenyl)piperazine-1-carboxylate (500 mg, 1.23 mmol) in dioxane (5 mL) was added HCl / dioxane (4 M, 5 mL) and the mixture was stirred at 20 ° C for 1 hour. LCMS showed that the starting material was completely consumed and showed a major peak with the expected mass. The mixture was concentrated in vacuo to give 3-((3-fluoro-4-(piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (420 mg, crude, HCl) as a gray solid. MS (M+H) + =307.1.

[0515] Step 2. (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)-2-fluorophenyl)piperazin-1-yl)propanoyl Synthesis of tert-butyl (4-(4-yl)piperidin-4-yl)carbamate

[0516] To a solution of 3-((3-fluoro-4-(piperazine-1-yl)phenyl)amino)piperidine-2,6-dione (420 mg, crude, HCl) and tert-butyl (1-(3-chloropropionyl)piperidin-4-yl)carbamate (1.78 g, 6.13 mmol) in DMF (10 mL) was added K2CO3 (677.33 mg, 4.90 mmol) and NaI (18.37 mg, 122.52 μmol), and the mixture was stirred at 90 ° C for 16 hours. LCMS showed that the starting material was completely consumed and showed a main peak with the expected mass. The reaction mixture was diluted with brine (30 mL) and extracted with EtOAc (20 mL×3). The combined organic layers were washed with brine (80 mL×3), dried over Na2SO4, and filtered. The filtrate was concentrated in vacuo to give a residue. The product was purified by flash chromatography on silica gel (Biotage; 20 g The residue was purified on a silica gel flash column with a gradient of 50-100% EtOAc / petroleum ether to 10% MeOH / EtOAc @ 100 mL / min to afford tert-butyl (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)-2-fluorophenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)carbamate (630 mg, 1.12 mmol, 91.71% yield) as a grey solid. MS (M+H) + =561.3.

[0517] Step 3. 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)-3-fluorophenyl) Synthesis of (amino)piperidine-2,6-dione (5)

[0518] To a solution of tert-butyl (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)-2-fluorophenyl)piperazine-1-yl)propanoyl)piperidin-4-yl)carbamate (630 mg, 1.12 mmol) in dioxane (10 mL) was added HCl / dioxane (4 M, 10 mL) and the mixture was stirred at 20 ° C for 0.5 hours. LCMS showed that the starting material was completely consumed and showed a major peak with the desired mass. The mixture was concentrated in vacuo to give 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazine-1-yl)-3-fluorophenyl)amino)piperidine-2,6-dione (550 mg, crude, HCl) as a yellow solid. MS (M+H) + =461.2.

[0519] Step 4. 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4, 5-b][1,4]diazepine -2-yl)amino)-N-(1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)-2-fluorophenyl)- Synthesis of 2-(4-(2-methyl-1-piperazin-1-yl)propionyl)piperidin-4-yl)-3-methoxybenzamide (Compound 26)

[0520] To 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine To a solution of 4-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazine-1-yl)-3-fluorophenyl)amino)piperidine-2,6-dione (300 mg, crude, HCl) in DMF (6 mL) was added HATU (344.27 mg, 905.42 μmol) and DIPEA (390.07 mg, 3.02 mmol, 525.70 μL), and the mixture was stirred at 20 ° C for 0.5 hours. 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazine-1-yl)-3-fluorophenyl)amino)piperidine-2,6-dione (300 mg, crude, HCl) was added, and the resulting mixture was stirred at 20 ° C for 16 hours. LCMS showed that the starting material was completely consumed and showed a main peak with the expected mass. The reaction mixture was diluted with brine (15 mL) and extracted with EtOAc (20 mL×3). The combined organic layers were washed with brine (80 mL x 3), dried over Na2SO4, and filtered. The filtrate was concentrated in vacuo to obtain a residue. The residue was purified by silica gel flash chromatography (Biotage; 10 g Silica gel flash column, eluent: 50-100% EtOAc / petroleum ether to 10% MeOH / EtOAc gradient @ 200 mL / min) and then purified by reverse phase HPLC (column: Waters Xbridge 150*25 mm*5 um; mobile phase: [water (NH4HCO3)-ACN]; B%: 36%-66%, 10 minutes). The eluate was lyophilized to obtain 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine) as a gray solid. -2-yl)amino)-N-(1-(3-(4-((2,6-dioxopiperidin-3-yl)amino)-2-fluorophenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-3-methoxybenzamide (200.9 mg, 218.97 μmol, 36.28% yield, 97% purity). MS (M+H) + =890.3.

[0521] 1 H NMR (400MHz, DMSO-d6) δ = 10.76 (s, 1H), 8.30-8.23 (m, 2H), 8.14 (d, J = 7.5Hz, 1H), 7.96 (s, 1H), 7.52-7.45 (m, 2H), 6.87-6.77(m,1H),6.54-6.47(m,1H),6.44-6.38(m,1H),5.79(d,J=7.7Hz,1H),4.83-4.70(m,1H),4.44-4.33(m,1 H),4.29-4.21(m,1H),4.09-4.00(m,3H),3.96-3.90(m,4H),3.29(s,3H),3.16-3.09(m,1H),2.89-2.81(m,4H),2 .76-2.54(m,11H),2.11-2.06(m,1H),1.96-1.81(m,5H),1.74-1.67(m,2H),1.64-1.56(m,4H),1.51-1.36(m,2H).

[0522] Example 27. 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine Synthesis of 1-(1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)-3-methoxybenzamide (Compound 27)

[0523]

[0524] Step 1. Synthesis of ethyl 1-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)piperidine-4-carboxylate (3)

[0525] A mixture of 2,6-bis(benzyloxy)-3-(4-bromophenyl)pyridine (1.9 g, 4.26 mmol), ethyl piperidine-4-carboxylate (803.07 mg, 5.11 mmol), RuPhos (198.64 mg, 425.69 μmol), Pd2(dba)3 (389.81 mg, 425.69 μmol) and Cs2CO3 (4.16 g, 12.77 mmol) in dioxane (40 mL) was degassed and purged with N2 three times. The resulting mixture was stirred at 100 ° C for 16 hours under N2 atmosphere. LCMS showed a peak with the desired mass (75%). The mixture was filtered through a pad of celite. The filtrate was concentrated in vacuo. The product was purified by flash chromatography on silica gel (Biotage; 20 g The residue was purified on a silica gel flash column with a 0-20% EtOAc / petroleum ether gradient at 100 mL / min as the eluent to afford ethyl 1-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)piperidine-4-carboxylate (1.9 g, 3.64 mmol, 85.40% yield) as a white solid. MS (M+H) + =523.2

[0526] Step 2. Synthesis of (1-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)piperidin-4-yl)methanol (5)

[0527] To a solution of ethyl 1-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)piperidine-4-carboxylate (1.1 g, 2.10 mmol) in THF (20 mL) was added LAH (160 mg, 4.22 mmol) at 0°C and the mixture was stirred at 25°C for 2 hours. LCMS showed a major peak with the desired mass. The mixture was quenched by addition of H2O (0.5 mL), NaOH (15% aqueous solution, 0.5 mL), H2O (1.5 mL), dried over Na2SO4 and filtered. The filtrate was concentrated in vacuo. The product was purified by flash chromatography on silica gel (Biotage; 20 g The residue was purified on a silica gel flash column with a 0-50% EtOAc / petroleum ether gradient at 100 mL / min as eluent to afford (1-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)piperidin-4-yl)methanol (0.9 g, 1.87 mmol, 88.97% yield) as a white solid. MS (M+H) + =481.2

[0528] Step 3. Synthesis of 3-(4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)piperidine-2,6-dione (6)

[0529] A mixture of (1-(4-(2,6-bis(benzyloxy)pyridin-3-yl)phenyl)piperidin-4-yl)methanol (800 mg, 1.66 mmol) and Pd / C (200 mg, 1.66 mmol, 10% purity) in CF3CH2OH (10 mL) and THF (2 mL) was degassed and purged with H2 (15 Psi) three times, and the mixture was stirred at 20°C for 16 hours. LCMS showed a major peak with the desired mass. The mixture was filtered through a pad of celite. The filtrate was concentrated in vacuo. The product was purified by flash chromatography on silica gel (Biotage; 20 g The residue was purified on a silica gel flash column (50-100% EtOAc / petroleum ether gradient @ 100 mL / min) to afford 3-(4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)piperidine-2,6-dione (480 mg, 1.59 mmol, 95.37% yield) as a white solid. MS (M+H) + =303.1

[0530] Step 4. Synthesis of 1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidine-4-carbaldehyde (7)

[0531] To a solution of 3-(4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)piperidine-2,6-dione (200 mg, 661.45 μmol) in DCM (1 mL) was added DMP (336.66 mg, 793.74 μmol) and the mixture was stirred at 20 ° C for 1 hour. LCMS showed that the expected mass was detected. The mixture was filtered through a pad of celite. The filtrate was concentrated in vacuo to give 1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidine-4-carbaldehyde (200 mg, crude) as a brown oil. MS (M+H) + =301.1

[0532] Step 5. ((1-((1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidin-4-yl)methyl)piperidin-4-yl) Synthesis of tert-butyl (methyl)carbamate (9)

[0533] A solution of 1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidine-4-carboxaldehyde (200 mg, crude product) and tert-butyl (piperidin-4-ylmethyl)carbamate (142.70 mg, 665.89 μmol) in DCM (2 mL) was stirred at 20 ° C for 0.5 hours, NaBH (OAc) 3 (423.39 mg, 2.00 mmol) was added, and the mixture was stirred at 20 ° C for 16 hours. LCMS showed a peak with the desired mass (98%). The reaction mixture was quenched with NaHCO 3 (5 mL) and extracted with EtOAc (10 mL × 3). The combined organic layer was washed with brine (20 mL × 2), dried over Na 2 SO 4, filtered, and the filtrate was concentrated in vacuo. The residue was purified by flash chromatography on silica gel (Biotage; 10 g The reaction mixture was purified by silica gel flash column with a gradient of 50-100% EtOAc / petroleum ether to 10% MeOH / EtOAc @ 100 mL / min as the eluent, and then triturated with a mixture solution (6 mL, DMF:ACN=5:1) at 20° C. for 0.5 h and filtered. The filter cake was dried in vacuo to give tert-butyl ((1-((1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate (74 mg, 148.40 μmol, 37.00% yield, 78% purity) as a purple solid. The filtrate was repurified by preparative HPLC (column: Phenomenex Synergi Polar-RP 100*25mm*4um; mobile phase: [water (TFA)-ACN]; B%: 10%-40%, 9 minutes), and the eluate was lyophilized to give tert-butyl ((1-((1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate (130 mg, 260.70 μmol, 65.00% yield, 93% purity) as a white solid. MS (M+H) + =499.3

[0534] Step 6. 3-(4-(4-((4-(aminomethyl)piperidin-1-yl)methyl)piperidin-1-yl)phenyl)piperidin-2,6- Synthesis of diketone (10)

[0535] To a solution of tert-butyl ((1-((1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate (130 mg, 212.18 μmol, TFA salt) in DCM (2 mL) at 20 ° C. TFA (241.94 mg, 2.12 mmol) was added. The mixture was stirred at 20 ° C. for 20 minutes. LCMS showed that the starting material was completely consumed and the expected mass was detected. The reaction mixture was concentrated in vacuo to give 3-(4-(4-((4-(aminomethyl)piperidin-1-yl)methyl)piperidin-1-yl)phenyl)piperidine-2,6-dione (109 mg, crude, TFA) as a yellow oil. MS (M+H) + =399.3

[0536] Step 7. 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4, 5-b][1,4]diazepine -2-yl)amino)-N-((1-((1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidin-4- Synthesis of 4-(2-methyl)piperidin-4-yl)methyl)-3-methoxybenzamide (Compound 27)

[0537] At 20 ° C, 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine To a solution of 4-(4-(4-((4-(aminomethyl)piperidin-1-yl)methyl)piperidin-1-yl)phenyl)piperidine-2,6-dione (109 mg, crude, TFA salt) in DMF (2 mL) and DIPEA (121.32 mg, 938.69 μmol) was added HATU (65.43 mg, 172.09 μmol) and DIPEA (60.66 mg, 469.34 μmol) in DMF (2 mL) and stirred for 10 minutes. The mixture was stirred at 20 ° C for 1 hour. LCMS showed that the starting material was completely consumed and showed a main peak with the expected mass (90%). The reaction mixture was diluted with H O (15 mL) and extracted with EtOAc (10 mL × 3). The combined organic layers were washed with brine (10 mL × 3), dried over Na2SO4, filtered and concentrated. The residue was purified by preparative TLC (SiO2, DCM:MeOH=10:1) to give a residue. This residue was combined with another batch (30 mg scale) for lyophilization to give 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine) as a white solid. -2-yl)amino)-N-((1-((1-(4-(2,6-dioxopiperidin-3-yl)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)-3-methoxybenzamide (113 mg, 136.48 μmol, 87.24% yield). MS (M+H) + =828.2

[0538] 1 H NMR (400MHz, DMSO-d6) δ = 10.76 (s, 1H), 8.48-8.35 (m, 1H), 8.31-8.23 (m, 2H), 7.97 (s, 1H), 7.55-7. 45(m,2H),7.03(d,J=8.6Hz,2H),6.88(d,J=8.7Hz,2H),4.84-4.70(m,1H),4.05(t,J=14.1Hz,2H), 3.93(s,3H),3.76-3.60(m,3H),3.33-3.30(m,5H),3.17(s,2H),3.04-2.71(m,2H),2.68-2.58(m,3 H),2.48-2.41(m,1H),2.21-2.07(m,2H),2.05-1.86(m,4H),1.82-1.54(m,12H),1.34-1.08(m,4H).

[0539] Example 28. 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine Synthesis of 1-(1-(1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)-3-methoxybenzamide (Compound 28)

[0540]

[0541] Step 1. Benzyl 4-((4-(((tert-Butoxycarbonyl)amino)methyl)piperidin-1-yl)methyl)piperidine-1-carboxylate (3) Synthesis

[0542] At 20 ℃, to MeOH (200mL) solution of 4-formylpiperidine-1-benzylformate (10g, 40.44mmol) and (piperidin-4-ylmethyl) tert-butyl carbamate (8.67g, 40.44mmol), add AcOH (2.43g, 40.44mmol, 2.31mL), after stirring for 30 minutes, then slowly add NaBH at 20 ℃ CN (2.54g, 40.44mmol), and the reaction mixture of gained is stirred at 20 ℃ for 16 hours. LCMS shows that raw material is completely consumed, and shows the peak (62%) with desired mass. Reactant mixture is diluted with H o (300mL) and extracted with EtOAc (150mL×3). By the organic layer NaHCO merged (100mL×3) washed, through Na sO dried, filtered. The filtrate is concentrated in vacuo. Residue is passed through flash chromatography on silica gel (80g Silica gel flash column, eluent 0-100% EtOAc / petroleum ether gradient @ 200 mL / min), followed by silica gel flash chromatography ( 80g Purification on silica gel flash column (0-100% EtOAc / petroleum ether gradient @ 200 mL / min) afforded benzyl 4-((4-(((tert-butoxycarbonyl)amino)methyl)piperidin-1-yl)methyl)piperidine-1-carboxylate (14 g, 31.42 mmol, 77.70% yield) as a white solid. MS (M+H) + =446.4.

[0543] Step 2. Synthesis of tert-butyl ((1-(piperidin-4-ylmethyl)piperidin-4-yl)methyl)carbamate (4)

[0544] To a solution of benzyl 4-((4-(((tert-butoxycarbonyl)amino)methyl)piperidin-1-yl)methyl)piperidine-1-carboxylate (2 g, 4.49 mmol) in EtOH (20 mL) under N2 was added Pd / C (1 g, 10% purity) and AcOH (2.10 g, 34.94 mmol, 2 mL). The suspension was degassed and purged with H2 three times. The mixture was stirred at 25°C under H2 (50 Psi) for 16 hours. LCMS showed that most of the starting material remained, and the reaction mixture was stirred at 20°C for another 16 hours. LCMS showed that half of the starting material remained. Additional Pd(OH)2 / C (1 g, 20% purity), AcOH (1 mL) were added, and the suspension was degassed and purged with H2 three times. The mixture was stirred at 25°C under H2 (50 Psi) for 16 hours. LCMS showed that the starting material was completely consumed and showed a peak with the desired mass (86%). The reaction mixture was filtered. The filter cake was washed with EtOH (40 mL × 3), and the filtrate was concentrated in vacuo to give tert-butyl ((1-(piperidin-4-ylmethyl)piperidin-4-yl)methyl)carbamate (1.5 g, crude product) as a colorless oil. MS (M+H) + =312.5.

[0545] Step 3. tert-Butyl ((1-((1-(4-nitrophenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate Synthesis of ester (5)

[0546] At 20 ℃, to tert-butyl ((1-(piperidin-4-ylmethyl)piperidin-4-yl)methyl)carbamate (1.5g, 4.04mmol) and 1-fluoro-4-nitrobenzene (455.76mg, 3.23mmol, 342.67μL) DMSO (40mL) solution, add KCO (2.23g, 16.15mmol). The mixture was stirred at 20 ℃ for 16 hours. LCMS showed a peak with the desired mass (26% peak). The reaction mixture was diluted with H2O (80mL) and extracted with EtOAc (30mL×3), the organic layer was washed with brine (30mL×3), dried over Na2SO4, and filtered. The filtrate was concentrated in vacuo. The product was purified by flash chromatography on silica gel (80g The residue was purified on a silica gel flash column with a 0-100% EtOAc / petroleum ether gradient at 200 mL / min as eluent to afford tert-butyl ((1-((1-(4-nitrophenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate (400 mg, 924.74 μmol, 22.90% yield) as a yellow oil. MS (M+H) + =433.3.

[0547] Step 4. tert-Butyl ((1-((1-(4-aminophenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate Synthesis of ester (6)

[0548] At 20 ℃, to tert-butyl ((1-((1-(4-nitrophenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate (400mg, 924.74μmol) in EtOH (10mL) and H o (2mL) solution, add Fe (258.23mg, 4.62mmol) and N h cl (247.32mg, 4.62mmol). The mixture was stirred at 80 ℃ for 2 hours. LCMS showed that most of the raw material remained, and additional N h cl (247.33mg, 4.62mmol) was added and the reaction mixture was stirred at 80 ℃ for another 1 hour. LCMS showed that 11% of the raw material remained, and showed a peak (83%) with the desired mass. The reaction mixture was diluted with H o (40mL) and diluted with Na c o was adjusted to pH=10, then extracted with EtOAc (30mL×3). The combined organic layer was dried over Na s o and filtered. The filtrate was concentrated in vacuo to give tert-butyl ((1-((1-(4-aminophenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate (370 mg, crude) as a brown solid. MS (M+H) + =403.3.

[0549] Step 5. ((1-((1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-4-yl)methyl)piperidine- Synthesis of tert-butyl 4-(4-yl)methyl)carbamate (8)

[0550] At 20 ℃, to ((1-((1-(4-aminophenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamic acid tert-butyl ester (185mg, 459.55μmol) and 3-bromopiperidine-2,6-dione (264.71mg, 1.38mmol) in ACN (1.5mL) solution, add NaHCO (231.63mg, 2.76mmol, 107.29μL). The mixture was stirred at 80 ℃ for 16 hours. LCMS showed that the raw material was completely consumed and showed a peak with the desired mass (36%). The reaction mixture was filtered and the filter cake was washed with EtOAc (20mL). The filtrate was concentrated in vacuo to give a crude product. The crude product was combined with another batch (350mg scale) for purification. The product was purified by flash chromatography on silica gel (12g The residue was purified by silica gel flash column with an eluent of 0-100% EtOAc / petroleum ether to 0-50% DCM / MeOH gradient @ 100 mL / min to give product A (248 mg). Product A was further purified by preparative TLC (SiO2, DCM:MeOH=5:1) to give an impure product, which was dissolved in a mixture of solvents (20 mL, ACN:H2O=1:3) to give tert-butyl ((1-((1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate (170 mg, 330.95 μmol, 72.02% yield) as a white solid. MS (M+H) + =514.3.

[0551] Step 6. 3-((4-(4-((4-(aminomethyl)piperidin-1-yl)methyl)piperidin-1-yl)phenyl)amino)piperidin-1-yl Synthesis of pyridine-2,6-dione (9)

[0552] To a solution of tert-butyl ((1-((1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)carbamate (138 mg, 268.65 μmol) in DCM (1 mL) was added TFA (307.00 mg, 2.69 mmol, 0.2 mL) and the mixture was stirred at 20 ° C for 1 hour. LCMS showed that the starting material was completely consumed and the expected mass was detected. The reaction mixture was concentrated in vacuo to give 3-((4-(4-((4-(aminomethyl)piperidin-1-yl)methyl)piperidin-1-yl)phenyl)amino)piperidine-2,6-dione (228 mg, crude, TFA salt) as a dark green solid. MS (M+H) + =414.4.

[0553] Step 7. b 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4, 5-b][1,4]diazepine -2-yl)amino)-N-((1-((1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-3-yl)amino)phenyl)piperidin-2-yl)amino)-N-((1-((1-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-3-yl)amino)-N-((1-((1-(4-( Synthesis of (4-pyridin-4-yl)methyl)piperidin-4-yl)methyl)-3-methoxybenzamide (Compound 28)

[0554] At 20 ° C, 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine To a solution of 3-((4-(4-(aminomethyl)piperidin-1-yl)methyl)piperidin-1-yl)phenyl)amino)piperidine-2,6-dione (114 mg, 216.08 μmol, TFA salt) in DMF (1 mL) and DIPEA (222.60 mg, 1.72 mmol, 0.3 mL) was added HATU (98.59 mg, 259.30 μmol) and DIPEA (74.20 mg, 574.11 μmol, 0.1 mL) in DMF (1 mL) and stirred for 10 minutes. The mixture was stirred at 20° C. for 1 hour. LCMS showed complete consumption of the starting material and a peak with the desired mass (26%) was observed. The reaction mixture was diluted with H2O (20 mL) and extracted with EtOAc (10 mL × 3). The combined organic layers were washed with brine (10 mL × 3), dried over Na2SO4, filtered and concentrated in vacuo. The crude product was purified by preparative TLC (SiO2, DCM: MeOH = 5: 1) and repurified by preparative HPLC (column: Phenomenex luna C18150 * 25mm * 10um; mobile phase: [water (TFA)-ACN]; gradient: 18% -48% B, over 9 minutes), and the eluent was lyophilized to give 4- ((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido [4,5-b] [1,4] diazepine as a white solid 4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperidin-4-yl)methyl)piperidin-4-yl)methyl)-3-methoxybenzamide (31.1 mg, 27.91 μmol, 12.91% yield, 96.2% purity, 2TFA). MS (M+H) + =843.4.

[0555] 1H NMR (400MHz, DMSO-d6) δ = 10.82 (s, 1H), 9.17-9.00 (m, 1H), 8.57-8.47 (m, 1H), 8.32-8.22(m,2H),8.09(s,1H),7.56-7.48(m,2H),7.36-7.30(m,1H),6.77(br d,J=8.8Hz,2H),4.83-4.72(m,1H),4.38(br dd,J=3.7,6.5Hz,1H),4.14-4.00(m,2H),3.93(s,3H),3.53-3.63(m,8H),3.33(s,3H),3.28-3.19(m,2H),3.13-2.98(m, 2H),2.80-2.68(m,1H),2.67-2.50(m,1H),2.28-2.10(m,1H),2.09-2.00(m,2H),1.97-1.82(m,6H),1.75-1.44(m,10H).

[0556] Example 29. 4-((9'-cyclopentyl-5'-methyl-6'-oxo-5',6',8',9'-tetrahydrospiro[cyclopropane-1,7'-pyrimido[4,5-b][1,4]diazepine Synthesis of 1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propionyl)piperidin-4-yl)-3-methoxybenzamide (Compound 29)

[0557]

[0558] Step 1. Synthesis of tert-butyl 4-(4-nitrophenyl)piperazine-1-carboxylate (3)

[0559] To a DMF (100 mL) solution of 1-fluoro-4-nitrobenzene (10 g, 70.87 mmol, 7.52 mL) and tert-butyl piperazine-1-formate (26.40 g, 141.74 mmol) was added KCO (29.38 g, 212.62 mmol). The mixture was stirred at 0 ° C for 1 hour and at 20 ° C for 16 hours. LCMS showed that 1-fluoro-4-nitrobenzene was completely consumed, and the desired mass was detected. The reaction mixture was diluted with H at 0 ° C. O (100 mL). The mixture was filtered and washed with water (100 mL) and petroleum ether (100 mL) to give tert-butyl 4- (4-nitrophenyl) piperazine-1-formate (25.7 g, crude product) as a yellow solid. MS (M+H) + =308.0.

[0560] Step 2. Synthesis of tert-butyl 4-(4-aminophenyl)piperazine-1-carboxylate (4)

[0561] To a solution of tert-butyl 4-(4-nitrophenyl)piperazine-1-carboxylate (10 g, crude product) in EtOH (100 mL) was added Pd / C (3 g, 10% purity). The suspension was degassed and purged with H2 three times. The mixture was stirred at H2 (15 Psi) and 25 ° C for 16 hours. LCMS showed that tert-butyl 4-(4-nitrophenyl)piperazine-1-carboxylate was completely consumed, and the desired mass was detected. The mixture was filtered and concentrated under reduced pressure to give tert-butyl 4-(4-aminophenyl)piperazine-1-carboxylate (9.18 g, crude product) as a red solid. The crude product was used in the next step without further purification. MS (M+H) + =278.2.

[0562] Step 3. Synthesis of tert-butyl 4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazine-1-carboxylate (6) become

[0563] To a solution of tert-butyl 4-(4-aminophenyl)piperazine-1-carboxylate (2.5 g, 9.01 mmol) and 3-bromopiperidine-2,6-dione (3.46 g, 18.02 mmol) in ACN (10 mL) was added NaHCO (3.51 g, 41.78 mmol, 1.63 mL). The mixture was stirred at 80 ° C for 16 hours. LCMS showed that tert-butyl 4-(4-aminophenyl)piperazine-1-carboxylate was completely consumed and the desired mass was detected. The reaction mixture was quenched with H2O (40 mL) at 25 ° C and extracted with EtOAc (160 mL). The organic layer was dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 80g The residue was purified on a silica gel flash column with a 0-40% EtOAc / petroleum ether gradient at 50 mL / min as eluent to afford tert-butyl 4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazine-1-carboxylate (1.7 g, 4.38 mmol, 48.55% yield) as a blue solid. MS (M+H) + =389.2.

[0564] Step 4. Synthesis of 3-((4-(piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (7)

[0565] To a solution of tert-butyl 4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazine-1-carboxylate (0.6 g, 1.54 mmol) in DCM (6 mL) was added TFA (3.07 g, 26.92 mmol, 2 mL). The mixture was stirred at 20 ° C for 1 hour. LCMS showed that tert-butyl 4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazine-1-carboxylate was completely consumed, and the expected mass was detected. The reaction mixture was concentrated under reduced pressure to give 3-((4-(piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (0.62 g, 1.54 mmol, 99.76% yield, TFA) as a blue oil. MS (M+H) + =289.3.

[0566] Step 5. (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-3-yl Synthesis of tert-butyl (4-pyridin-4-yl)carbamate (9)

[0567] To 3-((4-(piperazine-1-yl)phenyl)amino)piperidine-2,6-dione (0.77g, 1.91mmol, TFA) and (1-(3-chloropropionyl)piperidin-4-yl)carbamic acid tert-butyl ester (1.11g, 3.83mmol) in DMF (8mL) solution, DIPEA (2.23g, 17.22mmol, 3.00mL) and NaI (57.37mg, 382.73μmol) were added. The mixture was stirred at 40°C for 16 hours. LCMS showed 23% residual 3-((4-(piperazine-1-yl)phenyl)amino)piperidine-2,6-dione, and 16% expected mass was detected. The reaction mixture was quenched with H at 25°C o (20mL), then extracted with EtOAc (180mL). The organic layer was washed with brine (20 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 40g The residue was purified on a silica gel flash column using 0-10% MeOH / EtOAc at 50 mL / min as eluent to afford tert-butyl (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)carbamate (0.34 g, 626.53 μmol, 32.74% yield) as a black solid. MS (M+H) + =543.4.

[0568] Step 6. 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino) Synthesis of piperidine-2,6-dione (10)

[0569] To (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazine-1-yl)propionyl)piperidin-4-yl)t-butyl carbamate (300mg, 552.82μmol) in DCM (0.4mL) solution, add TFA (1.15g, 10.10mmol, 750.00μL).The mixture is stirred at 25 DEG C for 0.5 hour.LCMS shows that (1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazine-1-yl)propionyl)piperidin-4-yl)t-butyl carbamate is completely consumed, and desired mass is detected. The reaction mixture was concentrated under reduced pressure to give 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (300 mg, 539.01 μmol, 97.50% yield, TFA) as a green oil. MS (M+H) + =443.2.

[0570] Step 7. 4-((9'-cyclopentyl-5'-methyl-6'-oxo-5',6',8',9'-tetrahydrospiro[cyclopropane-1,7'- Pyrimido[4,5-b][1,4]diazepine ]-2'-yl)amino)-N-(1-(3-(4-(4-((2,6-dioxopiperidin-3-yl) Synthesis of 3-methoxybenzamide (Compound 29)

[0571] To 4-((9'-cyclopentyl-5'-methyl-6'-oxo-5',6',8',9'-tetrahydrospiro[cyclopropane-1,7'-pyrimido[4,5-b][1,4]diazepine To a solution of 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (300 mg, 539.01 μmol, TFA) in DMF (3 mL) was added HATU (307.42 mg, 808.51 μmol) and DIPEA (348.32 mg, 2.70 mmol, 469.43 μL). The mixture was stirred at 25° C. for 0.5 h. 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazin-1-yl)phenyl)amino)piperidine-2,6-dione (300 mg, 539.01 μmol, TFA) was then added and stirred at 25° C. for another 16 h. LCMS showed 11% of 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazine-1-yl)phenyl)amino)piperidine-2,6-dione remaining and 24% of the desired compound. DIPEA (371.00 mg, 2.87 mmol, 0.5 mL) was added and stirred at 25 ° C for another 2 hours. LCMS showed that 3-((4-(4-(3-(4-aminopiperidin-1-yl)-3-oxopropyl)piperazine-1-yl)phenyl)amino)piperidine-2,6-dione was completely consumed and the desired mass was detected. The reaction mixture was quenched by adding H2O (20 mL) at 25 ° C and then extracted with EtOAc (40 mL×3). The combined organic layers were washed with brine (20 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel ( 20g The residue was purified by silica gel flash column, eluent: 0-20% MeOH / EtOAc @ 50 mL / min) and preparative HPLC (column: Waters Xbridge 150*25 mm*5 um; mobile phase: [water (NH4HCO3)-ACN]; gradient: 30%-60% B over 10 minutes). The eluate was lyophilized to give 4-((9'-cyclopentyl-5'-methyl-6'-oxo-5',6',8',9'-tetrahydrospiro[cyclopropane-1,7'-pyrimido[4,5-b][1,4]diazepine) as a purple solid. ]-2'-yl)amino)-N-(1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-3-methoxybenzamide (73 mg, 79.60 μmol, 14.77% yield, 94% purity) and 4-((9'-cyclopentyl-5'-methyl-6'-oxo-5',6',8',9'-tetrahydrospiro[cyclopropane-1,7'-pyrimido[4,5-b][1,4]diazepine ]-2'-yl)amino)-N-(1-(3-(4-(4-((2,6-dioxopiperidin-3-yl)amino)phenyl)piperazin-1-yl)propanoyl)piperidin-4-yl)-3-methoxybenzamide (50.2 mg, 56.49 μmol, 10.48% yield, 94% purity). MS (M+H) + =862.7.

[0572] 1 H NMR (400MHz, DMSO-d6) δ=10.75(s,1H),8.40(d,J=8.1Hz,1H),8.12(d,J=7.6Hz,1H),7.98(s,1H),7.69(s,1H),7.55-7.39(m,2H),6 .75(d,J=9.0Hz,2H),6.60(d,J=8.9Hz,2H),5.37(d,J=7.3Hz,1H),4.94-4.77(m,1H),4.39(d,J=13.0Hz,1H),4.26-4.13(m,1H),4.1 2-4.00(m,1H),3.94(s,4H),3.47(s,2H),3.16(s,3H),3.15-3.08(m,1H),2.97-2.86(m,4H),2.78-2.63(m,2H),2.60-2.50(m,9H), 2.17-2.03(m,1H),1.95-1.76(m,5H),1.73-1.64(m,2H),1.63-1.56(m,2H),1.54-1.36(m,4H),0.95-0.83(m,2H),0.72-0.61(m,2H)

[0573] Example 30. 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine Synthesis of 4-((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino)cyclohexyl)-3-methoxybenzamide (Compound 30)

[0574]

[0575] Step 1. Synthesis of 1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidine-4-carboxaldehyde (2)

[0576] To a solution of 3-(3-fluoro-4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)piperidine-2,6-dione (2 g, 6.24 mmol) in DCM (50 mL) was added DMP (3.97 g, 9.36 mmol), and the mixture was stirred at 20 ° C for 2 hours. TLC (petroleum ether / EtOAc=1 / 1) showed that 3-(3-fluoro-4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)piperidine-2,6-dione was completely consumed and a new spot was formed. The mixture was filtered, and the filtrate was concentrated under reduced pressure to give 1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidine-4-carboxaldehyde (2 g, crude product) as a yellow oil. MS (M+H) + =319.4

[0577] Step 2. ((1r,4r)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methane Synthesis of benzyl)amino)cyclohexyl)carbamate (4)

[0578] To 1- (4- (2,6- dioxopiperidin-3-yl) -2- fluorophenyl) piperidine -4- carboxaldehyde (2g, 6.28mmol) and ((1r, 4r) -4- aminocyclohexyl) benzyl carbamate (1.56g, 6.28mmol) in DCM (20mL) solution, add AcOH (377.28mg, 6.28mmol, 359.66 μ L), and the mixture is stirred at 20 DEG C for 1 hour, then add NaBH (OAc) 3 (1.60g, 7.54mmol), and the resulting mixture is stirred at 20 DEG C for 12 hours. LCMS shows a peak (43%) with the desired mass. The reaction mixture is diluted with water (100mL) and extracted with DCM (50mL × 3). The combined organic layer is washed with saturated brine (200mL), dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by preparative HPLC (column: Phenomenexluna C18 150*40mm*15um; mobile phase: [water(TFA)-ACN]; gradient: 15%-45% B over 10 minutes) to give benzyl ((1r,4r)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino)cyclohexyl)carbamate (0.9 g, 1.57 mmol, 24.97% yield, 96% purity) as a yellow oil. MS (M+H) + =551.4

[0579] Step 3. 3-(4-(4-((((1r,4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)-3-fluorophenyl) Synthesis of piperidine-2,6-dione (5)

[0580] A solution of benzyl ((1r, 4r)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino)cyclohexyl)carbamate (450 mg, 817.20 μmol) in TFA (7.68 g, 67.31 mmol, 5 mL) was stirred at 40 ° C for 3 hours. LCMS showed a peak with the desired mass (79%). The mixture was concentrated under reduced pressure to give 3-(4-(4-((((1r, 4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)-3-fluorophenyl)piperidine-2,6-dione (0.4 g, 753.93 μmol, 92.26% yield, TFA) as a yellow oil. MS (M+H) + =417.3

[0581] Step 4. 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4, 5-b][1,4]diazepine -2-yl)amino)-N-((1r,4r)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluoro Synthesis of (4-(phenyl)piperidin-4-yl)methyl)amino)cyclohexyl)-3-methoxybenzamide (Compound 30)

[0582] To 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine To a solution of 1-(4-(4-((((1r, 4r)-4-aminocyclohexyl)amino)methyl)piperidin-1-yl)-3-fluorophenyl)piperidine-2,6-dione (0.2 g, 376.96 μmol, TFA salt) in DMF (5 mL) was added HATU (172.00 mg, 452.36 μmol) and DIPEA (194.88 mg, 1.51 mmol, 262.64 μL), and the mixture was stirred at 20 ° C for 1 hour. LCMS showed a peak with the desired mass (16%). The reaction mixture was diluted with water (50 mL) and extracted with EtOAc (30 mL × 3). The combined organic layers were washed with saturated brine (100 mL), dried over anhydrous Na2SO4, and filtered. The filtrate was concentrated under reduced pressure. The residue was purified by preparative HPLC (column: Phenomenex luna C18 150*25mm*10um; mobile phase: [water (FA)-ACN]; gradient: 17%-47% B over 10 minutes), and the eluent was lyophilized to give 4-((9-cyclopentyl-7,7-difluoro-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine) as a light yellow solid. -2-yl)amino)-N-((1r,4r)-4-(((1-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin-4-yl)methyl)amino)cyclohexyl)-3-methoxybenzamide (17.5 mg, 20.25 μmol, 5.37% yield, 97.9% purity). MS (M+H) + =846.4.

[0583] 1 H NMR (400MHz, DMSO-d6) δ = 10.83 (s, 1H), 8.26 (s, 1H), 8.26-8.17 (m, 4H), 7.54-7.43 (m, 2H),7.10-6.93(m,3H),4.88-4.68(m,1H),4.14-4.04(m,2H),3.94(s,3H),3.85-3.75( m,2H),3.33(s,3H),3.10-3.04(m,1H),3.00-2.92(m,2H),2.73-2.62(m,5H),2.27-2. 07(m,4H),2.05-1.82(m,8H),1.81-1.70(m,3H),1.65-1.55(m,4H),1.50-1.36(m,6H).

[0584] Example 31. N-(4-(1-amino-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)piperidin-1-yl)-4-((7,7-difluoro-9-isopropyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine Synthesis of 2-methoxy-2-amino-3-methoxybenzamide (Compound 31)

[0585]

[0586]

[0587] Step 1. tert-Butyl 4-(1-(((benzyloxy)carbonyl)amino)-2-methoxy-2-oxoethyl)piperidine-1-carboxylate (2) Synthesis

[0588] To a THF (50 mL) solution of tert-butyl 4-(1-amino-2-methoxy-2-oxyethyl)piperidine-1-formate (4.5 g, 16.52 mmol) was added CbzCl (3.38 g, 19.83 mmol, 2.83 mL) and KCO (6.85 g, 49.57 mmol). The mixture was stirred at 20 ° C for 16 hours. LCMS showed that the raw material was completely consumed and showed 15% of the expected mass. The reaction mixture was quenched by adding water (30 mL) at 0 ° C and extracted with EtOAc (50 mL × 2). The combined organic layer was washed with brine (40 mL), dried over NaSO, and filtered. The filtrate was concentrated under reduced pressure, and then flash chromatography on silica gel (40 g) was performed. Purification by silica gel flash column (0-30% EtOAc / petroleum ether gradient @ 60 mL / min) afforded tert-butyl 4-(1-((benzyloxy)carbonyl)amino)-2-methoxy-2-oxoethyl)piperidine-1-carboxylate (3.9 g, 9.59 mmol, 58.07% yield) as a colorless oil. MS (M-100+H) + =307.2

[0589] Step 2. Synthesis of tert-butyl 4-(1-((benzyloxy)carbonyl)amino)-2-hydroxyethyl)piperidine-1-carboxylate (3)

[0590] At 0 ° C, to a solution of tert-butyl 4-(1-(((benzyloxy)carbonyl)amino)-2-methoxy-2-oxoethyl)piperidine-1-carboxylate (3.9 g, 9.59 mmol) in THF (100 mL) was added LiBH4 (2 M, 9.59 mL). The mixture was stirred at 20 ° C for 16 hours. LCMS showed that the raw material was completely consumed and showed 37% of the expected mass. The reaction mixture was quenched by adding saturated NH4Cl aqueous solution (30 mL) at 0 ° C, and then extracted with EtOAc (40 mL × 2). The combined organic layer was washed with brine (30 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The product was purified by flash chromatography on silica gel (40 g The residue was purified on a silica gel flash column (0-60% EtOAc / petroleum ether gradient @ 60 mL / min) to afford tert-butyl 4-(1-(((benzyloxy)carbonyl)amino)-2-hydroxyethyl)piperidine-1-carboxylate (1.5 g, 3.73 mmol, 38.83% yield, 94% purity) as a colorless oil. MS (M-100+H) + =279.2

[0591] Step 3. Synthesis of tert-butyl 4-(1-((benzyloxy)carbonyl)amino)-2-oxoethyl)piperidine-1-carboxylate (4)

[0592] To a solution of DMSO (420.00 mg, 5.38 mmol, 420 μL) in DCM (9 mL) was slowly added (COCl) 2 (609.00 mg, 4.80 mmol, 420 μL) at -70°C, and the mixture was stirred at -70°C for 15 minutes. A solution of tert-butyl 4-(1-((benzyloxy)carbonyl)amino)-2-hydroxyethyl)piperidine-1-carboxylate (850 mg, 2.25 mmol) in DCM (9 mL) was then added at -70°C, and the mixture was stirred at -70°C for 20 minutes. TEA (1.36 g, 13.44 mmol, 1.87 mL) was added, and the mixture was stirred at -70°C for 30 minutes. After workup, 1 H NMR showed the desired product. The mixture was diluted with water (50 mL) and then extracted with DCM (20 mL×2). The combined organic layers were washed with water (20 mL), dried over Na 2 SO 4 , filtered, and concentrated under reduced pressure to give tert-butyl 4-(1-(((benzyloxy)carbonyl)amino)-2-oxoethyl)piperidine-1-carboxylate (860 mg, crude) as a yellow oil. MS (M+H) + =377.5

[0593] Step 4. 4-(1-(((Benzyloxy)carbonyl)amino)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorobenzene Synthesis of tert-butyl (1-methyl)piperazin-1-yl)ethyl)piperidine-1-carboxylate (6)

[0594] To a solution of 3-(3-fluoro-4-(piperazin-1-yl)phenyl)piperidine-2,6-dione (650 mg, 1.98 mmol, HCl) in DCM (10 mL) was added TEA (625.22 mg, 6.18 mmol, 860 μL) and MgSO (716.08 mg, 5.95 mmol), followed by tert-butyl 4-(1-(((benzyloxy)carbonyl)amino)-2-oxoethyl)piperidine-1-carboxylate (860 mg, 2.28 mmol) in DMF (10 mL), and the mixture was stirred at 25° C. for 15 minutes. NaBH(OAc) (840.67 mg, 3.97 mmol) was added and the mixture was stirred at 25° C. for 14 hours. LCMS showed 41% of the desired mass. The mixture was combined with another batch (150 mg scale), then diluted with water (30 mL) and extracted with EtOAc (10 mL×2). The combined organic layers were washed with water (10 mL×2), dried over Na 2 SO 4 and filtered. The filtrate was concentrated under reduced pressure. The product was purified by flash chromatography on silica gel (5 g The residue was purified on a silica gel flash column with a 0-10% MeOH / EtOAc gradient at 50 mL / min as eluent to afford tert-butyl 4-(1-((benzyloxy)carbonyl)amino)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)piperidine-1-carboxylate (720 mg, 994.22 μmol, 50.14% yield, 90% purity) as a yellow solid. MS (M+H) + =652.4

[0595] Step 5. (2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)-1-(piperidin-4-yl)- Synthesis of benzyl)ethyl)carbamate (7)

[0596] To a solution of tert-butyl 4-(1-(((benzyloxy)carbonyl)amino)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazine-1-yl)ethyl)piperidine-1-carboxylate (720 mg, 1.10 mmol) in DCM (5 mL) was added HCl / dioxane (4 M, 10 mL) and the mixture was stirred at 25 ° C for 1 hour. LCMS showed 87% of the expected mass. The mixture was concentrated under reduced pressure to give benzyl (2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazine-1-yl)-1-(piperidin-4-yl)ethyl)carbamate (660 mg, crude, HCl) as a yellow solid. MS (M+H) + =552.4

[0597] Step 6. (2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)-1-(1-nitroso)- Synthesis of benzyl (4-piperidin-4-yl)ethyl)carbamate (8)

[0598] To a solution of benzyl (2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)-1-(piperidin-4-yl)ethyl)carbamate (0.3 g, crude, HCl) in THF (6 mL) was added TEA (174.48 mg, 1.72 mmol, 240.00 μL) and t-BuONO (208.08 mg, 2.02 mmol, 240.00 μL), and the mixture was stirred at 60 ° C. under N2 for 14 hours. LCMS showed 50% of the desired mass. The mixture was concentrated under reduced pressure. The product was purified by flash chromatography on silica gel (5 g The residue was purified on a silica gel flash column with a 0-20% EtOAc / petroleum ether gradient at 50 mL / min as eluent to afford benzyl (2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)-1-(1-nitrosopiperidin-4-yl)ethyl)carbamate (0.5 g, 861.11 μmol, 84.40% yield) as a yellow solid. MS (M+H) + =581.4

[0599] Step 7. (1-(1-aminopiperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperidin- Synthesis of benzyl (1-oxazin-1-yl)ethyl)carbamate (9)

[0600] To a solution of benzyl (2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazine-1-yl)-1-(1-nitrosopiperidin-4-yl)ethyl)carbamate (100 mg, 172.22 μmol) and NH4Cl (28.00 mg, 523.45 μmol) in THF (1 mL) and H2O (0.3 mL) was slowly added Zn (56 mg, 856.40 μmol) and the mixture was stirred at 25 ° C for 1 hour. LCMS showed 75% of the expected mass. The mixture was merged with another batch (50 mg scale) and then diluted with THF (5 mL). The mixture was filtered and the filter cake was washed with THF (15 mL). The filtrate was concentrated under reduced pressure to give benzyl (1-(1-aminopiperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (190 mg, crude) as a yellow solid. MS (M+H) + =567.4

[0601] Step 8. (1-(1-(4-((7,7-difluoro-9-isopropyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimidine benzo[4,5-b][1,4]diazepine -2-yl)amino)-3-methoxybenzamido)piperidin-4-yl)-2-(4-(4-(2,6- Synthesis of benzyl (2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (11)

[0602] To 4-((7,7-difluoro-9-isopropyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine To a solution of 1-(1-aminopiperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (190 mg, crude) in DMF (3 mL) was added dimethylbenzyl (1-(1-aminopiperidin-4-yl)-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (190 mg, crude) and the mixture was stirred at 25° C. for 1 hour. LCMS showed 51% of the desired mass. The mixture was diluted with water (10 mL), then extracted with EtOAc (10 mL×3), the combined organic layers were washed with brine (10 mL×3), dried over Na 2 SO 4 , filtered and concentrated under reduced pressure, and then purified by preparative TLC (EtOAc:MeOH=10:1) to give (1-(1-(4-((7,7-difluoro-9-isopropyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine) as a yellow solid Benzyl 2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (0.2 g, 173.19 μmol, 52.13% yield, 84% purity). MS (M+H) + =970.5

[0603] Step 9. N-(4-(1-amino-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl) ethyl)piperidin-1-yl)-4-((7,7-difluoro-9-isopropyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4, 5-b][1,4]diazepine Synthesis of 2-methoxy-2-amino-3-methoxybenzamide (Compound 31)

[0604] (1-(1-(4-((7,7-difluoro-9-isopropyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine A solution of benzyl 2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)carbamate (170 mg, 147.21 μmol) in TFA (12.28 g, 107.70 mmol, 8 mL) was stirred at 60° C. for 6 hours. LCMS showed 55% of the desired mass. The mixture was concentrated under reduced pressure and then purified by preparative HPLC (column: Phenomenex luna C18 150*25mm*10um; mobile phase: [water(TFA)-ACN]; gradient: 17%-47% B over 10 minutes), and the eluate was lyophilized to give N-(4-(1-amino-2-(4-(4-(2,6-dioxopiperidin-3-yl)-2-fluorophenyl)piperazin-1-yl)ethyl)piperidin-1-yl)-4-((7,7-difluoro-9-isopropyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepine) as a white solid. -2-yl)amino)-3-methoxybenzamide (77.4 mg, 59.79 μmol, 40.62% yield, 91% purity, 3TFA). MS (M+H) + =836.5

[0605] 1 H NMR (400MHz, DMSO-d6) δ = 10.83 (s, 1H), 9.48-9.38 (m, 1H), 8.30-8.02 (m, 3H), 7.49-7.40 (m, 2H), 7 .12-6.93(m,3H),4.95-4.80(m,1H),4.08(t,J=12.9Hz,2H),3.93(s,3H),3.85-3.79(m,1H),3.58- 3.62(m,6H),3.32(s,3H),3.20-3.08(m,6H),3.02-2.91(m,1H),2.81-2.72(m,2H),2.71-2.58(m,1 H),2.50-2.47(m,3H),2.26-2.14(m,1H),2.04-1.94(m,1H),1.82-1.46(m,5H),1.30-1.16(m,6H).

[0606] <Experimental Example>

[0607] 1. Luciferase Assay Targeting PLK1

[0608] Preparation and culture of HeLa LgBit (PLK1-HiBitKI) cell line

[0609] A HeLa cell line was generated in which the LgBit vector was transfected and stably expressed. Next, gRNA and a donor were constructed to express the HiBit amino acid sequence, which is native to the cell, after the C-terminus of the PLK1 gene. This was then inserted into the cells along with a vector capable of expressing CRISPR / Cas9. Only cells that had completed insertion and knock-in were selected, subcultured, and used.

[0610] For cell culture, DMEM (Gibco, catalog number 11995-065; lot number 2646135), FBS (Gibco, catalog number 16000-044; lot number 2634213P), penicillin / streptomycin (PS) (Gibco, catalog number 15140-122; lot number 2441887), 100 mM 2 Cell culture dish (SPL, catalog number 20100), 150 mm 2 Cell culture dishes (SPL, catalog number 20150), 96-well culture plates (SPL, catalog number 30196), PBS pH 7.4 (Gibco, catalog number 10010-023; lot number 2509235), TrypLE TM Express (Gibco, catalog number 12605-010; lot number 2323417), a cell counter (hemocytometer) (all-in-one, catalog number 4-458-01), and 0.4% trypan blue solution (DYNEBIO, catalog number CBT3710; lot number 20221111).

[0611] Luciferase assay

[0612] The compounds of Examples were completely dissolved in DMSO (Sigma-Aldrich catalog number D2438, batch number RNBL5438) and used in the experiments.

[0613] In the case of HeLa LgBit (Plk1-HiBit KI), post-treatment compounds were released after thymidine blocking and the method was as follows. Thymidine (Sigma-Aldrich catalog number T9250-5G) was completely dissolved in ddH2O and used in the experiment. For thymidine blocking, the product was treated with 2mM thymidine and then incubated for 24 hours. For release and chemical treatment, the culture medium was aspirated and washed with 1× PBS. TrypLE was added TM The cells were incubated in a 37°C CO2 incubator (Thermo Fisher Science, catalog number 4111) for 5 minutes. The cells were neutralized by adding complete culture medium and counted using a counter. For each well of a 96-well culture plate (SPL), 3.3 × 10 4cells in a total culture medium volume of 150 μl and incubate in a CO2 incubator.

[0614] Each cell line was incubated in a CO2 incubator for 18 hours, and Endurazine (Promega, catalog number N257B) was added to each well to make up 4% of the total volume. After adding the compound of the example to a concentration of 300 nM in a 96-well white plate (SPL), the wavelength of the microplate reader (BMG Labtech, CLARIOstar Plus) was set to 470-480 nM, and then real-time luminescence was tracked. After 9 hours, luminescence values ​​were obtained and displayed as a bar graph using an Excel program.

[0615] The results are shown in the table below.

[0616] [Table 3]

[0617] Compound value Compound value 1 0.139 2 0.129 3 0.253 4 0.157 5 0.376 6 0.286 7 0.214 8 0.279 9 0.377 10 0.282 11 0.234 12 0.372 13 0.165 14 0.269 15 0.345 16 0.263 17 0.172 18 0.111 19 0.132 20 0.154 21 0.144 22 0.145 23 0.186 24 0.206 25 0.144 26 0.269 27 0.295 28 0.259 29 0.267 30 0.250 31 0.241

[0618] 2. Cell Viability Assay of NCI-H69 and NCI-H526 Cell Lines

[0619] Culture of NCI-H69 and NCI-H526 cell lines

[0620] NCI-H69 (hereinafter referred to as H69) and NCI-H526 (hereinafter referred to as H526) cell lines were purchased from Korea Cell Line Bank (KCLB, Seoul, South Korea). For cell culture, RPMI 1640 (Gibco, catalog number 22400-089; batch number 2537146), FBS (Gibco, catalog number 16000-044; batch number 2511328P), penicillin / streptomycin (PS) (Gibco, catalog number 15140-122; batch number 2441887), 75T cell culture flasks (SPL, catalog number 71075), 175T cell culture flasks (SPL, catalog number 71175), 96-well cell culture plates (SPL, catalog number 30096), PBS pH 7.4 (Gibco, catalog number 10010-023; batch number 2509235), TrypLE TM Express (Gibco, catalog number 12605-010; lot number 2323417), a cell counter (hemocytometer) (all-in-one, catalog number 4-458-01), and 0.4% trypan blue solution (DYNEBIO, catalog number CBT3710; lot number 20221111).

[0621] Cell viability assay

[0622] The compounds of the examples were completely dissolved in DMSO (Sigma-Aldrich catalog number D2438, batch number RNBL7287) and used in the experiment. 3×10 4 Cells were added and the cells were cultured in a total volume of 150 μl. Each compound was diluted 3 times from the highest concentration of 3000 nM to the lowest concentration of 0.46 nM. After the compound was processed into each well so that the total volume was 200 μl, it was cultured in a CO2 incubator (Thermo Fisher Science, catalog number 4111) for 5 days. Then, after EZ-Cytox (DOGEN, catalog number EZ-3000, batch number DLS2308) (20 μl per well) was processed, it was cultured in a CO2 incubator for 4 hours. The absorbance of the fully cultured sample was measured by setting the wavelength of a microplate reader (BMG Labtech, CLARIOstar Plus) to 450 nM, and the measurement was performed after shaking in a microplate reader for 3 minutes before measurement. The final measured values ​​were arranged with an Excel program, the chart was displayed by a Prism-GraphPad program, and the IC 50 value.

[0623] The cell viability results of H69 and H526 cell lines are shown in Tables 4 and 5, respectively. (A: IC 50 Less than 20nM, B:IC 50 50nM or less, C:IC 50 is 100 nM or less).

[0624] [Table 4]

[0625] Compound active Compound active 1 A 2 A 3 A 4 A 5 A 6 B 7 B 8 A 9 C 10 C 11 B 12 C 13 C 14 B 15 C 16 C 17 B 18 A 19 B 20 A 21 A 22 B 23 A 24 A 25 A 26 B 27 B 28 C 29 C 30 B 31 B

[0626] [Table 5]

[0627] Compound active Compound active 1 A 2 A 3 A 4 A 5 A 6 A 7 A 8 A 9 A 10 B 11 A 12 B 13 A 14 A 15 B 16 B 17 A 18 A 19 B 20 A 21 A 22 A 23 A 24 A 25 A 26 A 27 B 28 B 29 B 30 B 31 B

Claims

1. A compound represented by the following formula I: [Formula I] in: L1 is a covalent bond or -(X5) 1～3 -, wherein X5 is each independently -CH2- or -NH-, provided that -NH- is absent or occurs at most once in L1; L2 is a covalent bond or -(X6) 1～3 -, wherein X6 is each independently -CH2-, -C(O)-, -NH- or -CH(NH2)-, provided that -C(O)-, -NH-, -N(CH3)- and -CH(NH2) are each independently absent or present at most once in L2; L3 is Among them, L3 passes covalently bonded to X4; X1, X2, X3 and X4 are each independently CH or N; X7 and X 8a Each is independently a covalent bond or -CH2-; X 8b is -H or -CH3; and R1 is -OCH3 or -OCF3; wherein ULM is a moiety represented by the following formula II-1, II-2 or II-3: [Formula II-1] [Formula II-2] [Formula II-3] in: Ring U is phenyl or a 5- or 6-membered heteroaryl group; U1 is -NH-, -NHCH2-, -NHCH2CH2-, -CH2NH-, -CH2CH2NH-, -NHCO-, -CONH- or -O-; U2 is CH2 or C(O); and R U It's a halogen.

2. The compound according to claim 1, wherein Formula I is the following Formula I-1: [Formula I-1] Among them L 1a It is -CH2-, -NH-, -CH2CH2-, -NHCH2-, -CH2NH-, -CH2CH2CH2-, -NHCH2CH2-, -CH2NHCH2- or -CH2CH2NH-.

3. The compound according to claim 1, wherein Formula I is the following Formula I-2: [Formula I-2] in: X9 is -CH2- or -CH(NH2)-.

4. The compound according to claim 1, wherein Formula I is the following Formula I-3: [Formula I-3] where X 10 is a covalent bond, -NH-, or -CH(NH2)-; and X 11 It is a covalent bond or -CH2-.

5. The compound according to claim 1, wherein Formula I is represented by the following formula I-4: [Formula I-4] in: L 1b It is a covalent bond or -CH2NH-; L 2b is a covalent bond, -CH2NH-, -CH2N(CH3)-, or -CH2CH(NH2)C(O)-; X 8a is a covalent bond or -CH2-; and X 8b It is -H or -CH3.

6. The compound according to claim 1, wherein the compound is selected from compounds 1 to 25:

7. A compound represented by the following formula III: [Formula III] in: L2 is -CH2-, -NHCH2-, -CH2NH-, -CH(NH2)CH2-, -CH2CH(NH2)-, -C(O)CH2CH2- or -CH2CH2C(O)-; X1, X2, X3 and X4 are each independently CH or N; X7 is a covalent bond or -CH2-; R 2a and R 2b Is - halogen, or R 2a and R 2b are linked to each other to form a 3- to 6-membered ring; and R3 is -C 1-3 Alkyl or 3- to 7-membered cycloalkyl; wherein ULM is a moiety represented by the following formula II-4: [Formula II-4] wherein U3 is a covalent bond or -NH-; and R U It's a halogen.

8. The compound according to claim 7, wherein the compound is selected from compounds 26 to 31:

9. The compound according to any one of claims 1 to 8, wherein the compound induces degradation of polo-like kinase 1 (PLK1) protein.

10. A pharmaceutical composition comprising a compound according to any one of claims 1 to 9 and at least one pharmaceutically acceptable carrier.

11. A pharmaceutical composition comprising the compound according to any one of claims 1 to 9, wherein the compound is conjugated to an antibody or an antigen-binding fragment thereof via a linker.

12. A pharmaceutical composition for treating cancer, benign tumors or nervous system diseases, comprising the compound according to any one of claims 1 to 9.

13. An antibody-drug conjugate comprising an antibody or an antigen-binding fragment thereof and a compound according to any one of claims 1 to 9, wherein the compound is conjugated to the antibody or the antigen-binding fragment thereof via a linker.

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