WO2018196768A1 - Heterocyclic compound serving as pd-l1 inhibitor - Google Patents

Abstract

The present invention relates to the field of medical chemistry, and relates to a heterocyclic compound serving as a PD-L1 inhibitor. Specifically, the present invention relates to a compound represented by formula A, or an isomer, pharmaceutically acceptable salt, solvate or prodrug thereof, preparation methods therefor, a pharmaceutical composition containing these compounds, and a use of these compounds or composition in treating cancers or infectious diseases.

Description

Heterocyclic compounds as PD-L1 inhibitors Technical field

The present invention belongs to the field of medical chemistry, and relates to a class of heterocyclic compounds as PD-L1 inhibitors and uses thereof. In particular, the present invention relates to a compound represented by formula A or an isomer thereof, a pharmaceutically acceptable salt, Solvates or prodrugs, methods for their preparation, and pharmaceutical compositions containing these compounds and the use of such compounds or compositions for the treatment of cancer or infectious diseases.

Background technique

Programmed Cell Death-1 (PD-1) and its ligand PD-L1 (B7·H1) belong to the CD28/B7 superfamily. PD-1 is mainly expressed on the membrane surface of T cells, B cells, and natural killer cells (NK cells). PD-L1 is mainly expressed on mature CD4T cells, CD8 T cells, B cells, monocytes, and dendrites. Hematopoietic cells such as dendritic cells (DCs), macrophages, and some non-hematopoietic cells, such as membrane surfaces of endothelial cells, islet cells, mast cells, and the like. Among them, PD-L1 is highly expressed in various tumors, such as lung cancer, gastric cancer, multiple bone marrow, melanoma and breast cancer. The expression of PD-L1 on the surface of tumor cells interacts with the ligand on the surface of T cells, which can induce apoptosis of T cells or reduce the reactivity of T cells, thereby inhibiting the tumor immune response and allowing tumor cells to escape immune attack. Therefore, blocking the antagonist of PD1-PDL1 signaling pathway can promote the activation of T cells, reverse the tumor immune microenvironment, and enhance the endogenous anti-tumor immune effect. Targeting PD-1/PD-L1 inhibitors has broad application prospects in the field of tumor immunotherapy.

Currently, anti-PD-1/PD-L1 antibody therapy has been shown to have a clinical advantage, however, biomacromolecules also have some disadvantages such as immunogenicity and limitations of the route of administration. Therefore, there is still a need to develop targeted PD-1/PD-L1 inhibitors with better pharmacodynamics. The inventors of the present invention have found that a class of small molecule drugs can specifically modulate and/or mediate the transduction of PD-L1 and its related protein kinases for the treatment of diseases associated with PD-1/PD-L1.

Summary of the invention

It is an object of the present invention to provide a compound of the formula A or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof,

among them:

X and Y are each independently selected from N, O and S, and when X is N, Y is selected from O and S; when X is O or S, Y is N; when Y is N, X is selected from O and S; When Y is O or S, X is N;

When X is N, Y is selected from O and S or Y is O or S, and X is N, the group

for

When X is O or S, Y is N or Y is N, and X is selected from O and S, the group

for

R _{1 is} selected from the side chains of the amino acids Ser and Thr;

R _{2 is} selected from the group consisting of the amino acid Ser and Thr residues;

R _{3 is} selected from the group consisting of H, —(CH ₂ ) _m C(O)OR ₄ , —(CH ₂ ) _m C(O)N(R ₅ )(R ₆ ) and —(CH ₂ ) _m CN, wherein R ₄ , R ₅ , R ₆ are each independently selected from H and alkyl, and m is 0, 1, 2, 3 or 4;

n is 1, 2, 3 or 4.

In some preferred embodiments, a compound of Formula A, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, which is represented by Formula I or II a compound or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug:

Wherein: Q is selected from O and S; and R ₁ , R ₂ and R ₃ are as defined in Formula A.

In some embodiments, a compound of Formula A, Formula I or II, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, according to the invention, wherein:

R _{1 is} selected from the side chains of the amino acids Ser and Thr;

R _{2 is} selected from the group consisting of the amino acid Ser and Thr residues;

R _{3 is} selected from the group consisting of H, —(CH ₂ ) _m C(O)OR ₄ , —(CH ₂ ) _m C(O)N(R ₅ )(R ₆ ) and —(CH ₂ ) _m CN, wherein R ₄ , R ₅ and R ₆ are each independently selected from H and C _1-6 alkyl, and m is 1, 2, 3 or 4;

n is 1, 2, 3 or 4.

In some embodiments, a compound of Formula A, Formula I or II, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, according to the invention, wherein:

R _{1 is} selected from

R _{2 is} selected from

R _{3 is} selected from the group consisting of H, —(CH ₂ ) _m C(O)OR ₄ , —(CH ₂ ) _m C(O)N(R ₅ )(R ₆ ) and —(CH ₂ ) _m CN, wherein R ₄ , R ₅ and R ₆ are each independently selected from H and C _1-6 alkyl, and m is 1, 2, 3 or 4;

n is 1, 2, 3 or 4.

In some embodiments, a compound of Formula A, Formula I or II, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, according to the invention, wherein:

R _{1 is} selected from

R _{2 is} selected from

R _{3 is} selected from H,

And n is 1, 2, 3 or 4.

In some embodiments, the compound of Formula A, Formula I or II above, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof thereof, according to the invention, wherein

Selected from

In some embodiments, a compound of Formula A, Formula I or II, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, according to the invention, wherein:

R _{1 is} selected from

R _{2 is} selected from

with

Selected from

A compound having the formula A or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug thereof, non-limiting examples of which include:

Another object of the present invention is to provide a compound of the formula B or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug thereof,

among them:

X and Y are each independently selected from N, O and S, and when X is N, Y is selected from O and S; when X is O or S, Y is N; when Y is N, X is selected from O and S; When Y is O or S, X is N;

When X is N, Y is selected from O and S or Y is O or S, and X is N, the group

for

When X is O or S, Y is N or Y is N, and X is selected from O and S, the group

for

R _{7 is} selected from the side chain of the amino acids Asn, Gln, Asp, Glu;

R _{8 is} selected from the group consisting of the amino acid Ser and Thr residues;

R ₉ and R ₁₀ are each independently selected from H, an alkyl group and an alkylhydroxy group, and R ₉ and R _{10 are} not simultaneously H, and

R ₉ or R ₁₀ together with the amino group attached to its alpha carbon position form a nitrogen heterocycloalkyl or a nitrogen heterocycloalkyl group, optionally a one or more Substituted with a substituent selected from the group consisting of a hydroxyl group, a hydroxyalkyl group, a cyano group, an amino group, a halogen, and a nitro group; or

R ₉ and R ₁₀ together with the C atom to which they are attached form a cycloalkyl or oxacycloalkyl group, which is optionally selected from one or more selected from the group consisting of a hydroxyl group and a hydroxyalkyl group. Substituted by a substituent of a cyano group, an amino group, a halogen or a nitro group.

In a preferred embodiment, a compound of the formula B, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, is a compound of the formula III or IV. Or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof:

Wherein: Q is selected from O and S, and R ₇ , R ₈ , R ₉ and R ₁₀ are as defined in Formula B.

In some embodiments, the compound of Formula B, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal, or prodrug thereof, according to the present invention, wherein:

R _{7 is} selected from the side chain of the amino acids Asn, Gln, Asp, Glu;

R _{8 is} selected from the group consisting of the amino acid Ser and Thr residues;

R ₉ and R ₁₀ are each independently selected from the group consisting of H, C _1-6 alkyl and C _1-6 alkyl hydroxy, and R ₉ and R _{10 are} not H at the same time, and

R ₉ or R ₁₀ together with the amino group attached to its alpha carbon position form an aza C _3-6 cycloalkyl or a nitrogenoxa C _3-6 cycloalkyl group, said aza C _3-6 cycloalkyl or nitrox a hetero C _3-6 cycloalkyl group optionally substituted with one or more substituents selected from the group consisting of hydroxyl, hydroxy C _1-6 alkyl, cyano, amino, halogen, nitro;

R ₉ and R ₁₀ together with the C atom to which they are attached form a C _3-6 cycloalkyl or oxa C _3-6 cycloalkyl group, said C _3-6 cycloalkyl or oxa C _3-6 cycloalkane The group is optionally substituted with one or more substituents selected from the group consisting of a hydroxyl group, a hydroxy C _1-6 alkyl group, a cyano group, an amino group, a halogen, and a nitro group.

In another preferred embodiment, a compound of the formula B, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein R ₉ is H, R ¹⁰ is amino group formed on the α-carbon position with C _3-6 cycloalkyl aza, aza said C _3-6 cycloalkyl optionally substituted with one or more substituents selected from hydroxy, hydroxy C _1-6 alkyl, Substituted by a substituent of a cyano group, an amino group, a halogen or a nitro group.

In another preferred embodiment, a compound of the formula B, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein R _{9 is} selected from C _1-3 An alkyl group, R _{10 is} selected from C _1-3 alkyl groups, and R ₉ and R ₁₀ together with the C atom to which they are attached form a C _3-6 cycloalkyl group, optionally a C _3-6 cycloalkyl group Or a plurality of substituents selected from the group consisting of a hydroxyl group, a hydroxyalkyl group, a cyano group, an amino group, a halogen, and a nitro group.

In another preferred embodiment, a compound of the formula B, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein R _{9 is} selected from C _1-3 An alkyl group, R _{10 is} selected from a C _1-3 hydroxyalkyl group, and R ₉ and R ₁₀ together with the C atom to which they are attached form an oxa C _3-6 cycloalkyl group, said oxa C _3-6 cycloalkyl group It is optionally substituted with one or more substituents selected from the group consisting of a hydroxyl group, a hydroxyalkyl group, a cyano group, an amino group, a halogen, and a nitro group.

A compound having the formula B or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug thereof, non-limiting examples of which include:

Another object of the present invention is to provide a compound of the formula C or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug,

among them:

X and Y are each independently selected from N, O and S, and when X is N, Y is selected from O and S; when X is O or S, Y is N; when Y is N, X is selected from O and S; When Y is O or S, X is N;

When X is N, Y is selected from O and S or Y is O or S, and X is N, the group

for

When X is O or S, Y is N or Y is N, and X is selected from O and S, the group

for

R _{11 is} selected from the side chains of the amino acids Ser and Thr;

R _{12 is} selected from the group consisting of amino acid Asn, Gln, Asp, Glu side chain;

R _{15 is} selected from the group consisting of H and alkyl;

R ₁₃ and R ₁₄ are each independently selected from H and alkyl, and R ₁₃ and R _{14 are} not H at the same time, and

R ₁₃ , R ₁₄ together with the C atom to which they are attached form a cycloalkyl group; or

R ₁₃ or R ₁₄ together with the imino group to which the α carbon position is bonded forms a nitrogen heterocycloalkyl group, or R ₁₄ together with R ₁₅ and the atom to which they are attached form an optionally substituted lactone cycloalkyl group.

The cycloalkyl, azacycloalkyl or lactone cycloalkyl is optionally substituted with one or more substituents selected from the group consisting of hydroxyl, hydroxyalkyl, cyano, amino, halogen, nitro;

In a preferred embodiment, a compound of the formula C, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, is a compound of the formula V or VI. Or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof:

Wherein: Q is selected from O and S; and R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₅ are as defined in Formula C.

In a preferred embodiment, a compound of the formula C, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein R ₁₃ , R ₁₄ and The attached C atoms together form a C _3-6 cycloalkyl group;

In another preferred embodiment, a compound of the formula C, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein R ₁₄ and its alpha carbon position The attached imino groups together form an aza C _3-6 cycloalkyl group;

In another preferred embodiment, a compound of the formula C, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein R ₁₄ and R ₁₅ and The attached atoms together form a lactone C _3-6 cycloalkyl group which is substituted by one or more selected from the group consisting of hydroxyl, oxo, hydroxyalkyl, cyano, amino, halogen, nitro Substituted by

A compound having the formula C or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug thereof, non-limiting examples of which include:

Another object of the present invention is to provide a process for the preparation of a compound of the formula I, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, comprising the steps of:

(1) a compound of the formula ia and a compound of the formula ib are subjected to a condensation reaction to form a compound of the formula ic;

(2) cyclizing a compound of the formula ic to give a compound of the formula id;

(3) a compound of the formula id is reacted with an amine compound to give a compound of the formula IE;

(4) a nucleophilic substitution reaction of a compound of the formula IE with a compound of the formula i to give a compound of the formula ig;

(5) under acidic conditions, a compound of formula ig is hydrolyzed to give a compound of formula I;

Wherein: Pg ₁ represents a protecting group of R ₁ ; Pg ₂ represents a protecting group of R ₂ ; as described in Formula I, R ₁ and R ₂ are each selected from the group consisting of the amino acid Ser and Thr side chains, in order to avoid the amino acid Ser or Thr side chain In the further reaction during the reaction, a conventional hydroxy protecting group may be used to protect the amino acid Ser or Thr side chain, and Pg ₁ and Pg _{2 are} preferably tert-butyl ( ^t Bu);

Pg ₃ represents a protecting group of R ₃ or is absent; as described in Formula I, R _{3 is} selected from H, -(CH ₂ ) _m C(O)OR ₄ , -(CH ₂ ) _m C(O)N ( R ₅ )(R ₆ ) and —(CH ₂ ) _m CN; when R ₃ is a group containing a hydroxyl group or an amino group which is susceptible to change in further reaction, it can be protected by a conventional protecting group; Pg ₄ Pg ₅ represents an amino protecting group.

Another object of the present invention is to provide a process for the preparation of a compound of the formula II, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, comprising the steps of:

(1) a compound of the formula ia and a compound of the formula iib are subjected to a condensation reaction to form a compound of the formula iic;

(2) cyclization of a compound of formula iic to give a compound of formula iid;

(3) a compound of the formula iid is reacted with an amine compound to give a compound of the formula iie;

(4) a compound of the formula iie and a compound of the formula if subjected to nucleophilic substitution to give a compound of the formula iig;

(5) under acidic conditions, a compound of formula iig is hydrolyzed to give a compound of formula II;

Wherein: Pg ₁ represents a protecting group for R ₁ ; Pg ₂ represents a protecting group for R ₂ ; as described in Formula II, R ₁ and R ₂ are each selected from the group consisting of the amino acid Ser and Thr side chains, in order to avoid the amino acid Ser or Thr side chain Further reaction in the reaction, the conventional hydroxyl group can be used to protect the hydroxyl group, Pg ₁ , Pg ₂ is preferably tert-butyl ( ^t Bu);

Pg ₃ represents the protection or absence of R ₃ ; as described in Formula II, R _{3 is} selected from H, -(CH ₂ ) _m C(O)OR ₄ , -(CH ₂ ) _m C(O)N(R ₅ ) (R ₆ ) and -(CH ₂ ) _m CN; when R ₃ is a group which contains a hydroxyl group or an amino group and is susceptible to change in further reaction, it can be protected by a conventional protecting group;

Pg ₄ and Pg ₅ represent an amino protecting group.

Another object of the present invention is to provide a compound of Formula B, Formula C, Formula III, Formula IV, Formula V or Formula VI or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate thereof, The preparation method of the crystallization or prodrug, according to the preparation method of the compound of the general formula I and the general formula II provided above, the person skilled in the art can obtain the general formula B, the general formula C, and the conventional raw material according to the conventional knowledge in the field of organic synthesis. Formula III, Formula IV, Formula V or Formula VI.

Another object of the present invention is to provide a pharmaceutical composition comprising, for example, Formula A, Formula B, Formula C, Formula I, Formula II, Formula III, Formula IV, A compound of the formula V or formula VI, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, and a pharmaceutically acceptable carrier.

Another object of the present invention is to provide a compound of the formula A, formula B, formula C, formula I, formula II, formula III, formula IV, formula V, formula VI. Or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof or a pharmaceutical composition comprising the same for use in the manufacture of a medicament for the treatment of cancer or an infectious disease.

In a preferred embodiment, a compound of formula A, formula B, formula C, formula I, formula II, formula III, formula IV, formula V or formula VI Or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, or a pharmaceutical composition comprising the same, for use in the manufacture of a medicament for the treatment of a cancer or an infectious disease, wherein the cancer comprises But not limited to melanoma, brain tumors (gliomas with malignant astroglia and oligodendroglioma), esophageal cancer, stomach cancer, liver cancer, pancreatic cancer, colorectal cancer (colon cancer) , rectal cancer, etc.), lung cancer (non-small cell lung cancer, small cell lung cancer, primary or metastatic squamous cell carcinoma, etc.), kidney cancer, breast cancer, ovarian cancer, prostate cancer, skin cancer, neuroblastoma, sarcoma, Osteochondroma, osteoma, osteosarcoma, seminoma, testicular tumor, uterine cancer (cervical cancer, endometrial cancer, etc.), head and neck cancer (maxillary cancer, laryngeal cancer, pharyngeal cancer, tongue cancer, intraoral cancer) Etc., multiple myeloma, malignant lymphoma (reticulocyte sarcoma, lymphosarcoma) , Hodgkin's lymphoma, etc., polycythemia vera, leukemia (acute myeloid leukemia, chronic myeloid leukemia, acute lymphocytic leukemia, chronic lymphocytic leukemia, etc.), thyroid neoplasms, ureteral tumors, bladder tumors, gallbladder cancer, Cholangiocarcinoma, chorionic epithelial cancer or pediatric tumor (Ewing familial sarcoma, Wilms' sarcoma, rhabdomyosarcoma, angiosarcoma, embryonic testicular cancer, neuroblastoma, retinoblastoma, hepatic blastoma, nephroblast Combination of tumors, etc.) and said cancer.

In another preferred embodiment, a formula of formula A, formula B, formula C, formula I, formula II, formula III, formula IV, formula V or formula VI Use of a compound, or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug thereof, or a pharmaceutical composition comprising the same, in the manufacture of a medicament for the treatment of a cancer or an infectious disease, wherein the infection Sexual diseases include, but are not limited to, bacterial, viral, and fungal infections.

In a specific embodiment, a compound of Formula A, Formula B, Formula C, Formula I, Formula II, Formula III, Formula IV, Formula V, or Formula VI It has a significant inhibitory effect on colon cancer.

Explanation of terms:

Terms used in the specification and claims have the following meanings unless stated to the contrary.

"Hydrogen" and "carbon" in the compounds of the present invention include all isotopes thereof. Isotopes are understood to include those atoms having the same number of atoms but having different mass numbers, such as isotopes of hydrogen including lanthanum and cerium, and isotopes of carbon including ¹³ C and ¹⁴ C.

The term "stereoisomer" refers to a molecule having the same atomic composition and attachment in the same manner, but having a three-dimensional arrangement differently, including optical isomers, geometric isomers (also known as cis-trans isomers), "chiral" It is a molecule that has properties that cannot overlap with its mirror image; "non-chiral" refers to a molecule that can overlap with its mirror image. Optical isomers are divided into enantiomers and diastereomers. "Enantiomer" refers to two isomers of a compound that are not superimposable but are mirror images of each other. "Diastereomer" refers to a stereoisomer that has two or more chiral neutralities and whose molecules are not mirror images of each other. Diastereomers have different physical properties such as melting point, boiling point, spectral properties and reactivity. The mixture of diastereomers can be separated by high resolution analytical procedures such as electrophoresis and chromatography, such as HPLC.

All stereoisomeric forms of the compounds of the invention include, but are not limited to, diastereomers, enantiomers, cis and trans isomers, and mixtures thereof, such as racemic mixtures. Many organic compounds exist in optically active forms, that is, they have the ability to rotate planes of plane polarized light. In describing optically active compounds, the prefix D, L or R, S is used to indicate the absolute configuration of the molecular chiral center. The prefix D, L or (+), (-) is used to designate the sign of the plane-polarized light rotation of the compound, (-) or L means that the compound is left-handed, and the prefix (+) or D means that the compound is right-handed. The chemical structures of these stereoisomers are the same, but their stereostructures are different. A particular stereoisomer can be an enantiomer, and a mixture of isomers is often referred to as a mixture of enantiomers. The 50:50 mixture of enantiomers is referred to as a racemic mixture or a racemate, which may result in no stereoselectivity or stereospecificity during the chemical reaction. The terms "racemic mixture" and "racemate" refer to an equimolar mixture of two enantiomers that lack optical activity.

Depending on the choice of starting materials and methods, the compounds of the invention may be one of the possible isomers or mixtures thereof, such as racemates and mixtures of diastereomers (depending on the number of asymmetric carbon atoms) The form exists. Optically active (R)- or (S)-isomers can be prepared using chiral synthons or chiral reagents, or resolved using conventional techniques.

The resulting mixture of any stereoisomers can be separated into pure or substantially pure geometric isomers, enantiomers, diastereomers, for example, by chromatography, depending on the difference in physicochemical properties of the components. Method and / or step crystallization.

The "pharmaceutically acceptable salt" of the present invention means an acid and/or a basic salt of a compound with an inorganic and/or organic acid and a base form, and also a zwitterionic salt (internal salt). The compound of the present invention contains an amino acid side chain and an amino acid residue, so that it can form an internal salt or a salt corresponding to other inorganic inorganic and/or organic acid and base forms.

The "solvate" of the present invention means a form of the compound of the present invention which forms a solid or liquid complex by coordination with a solvent molecule. Hydrates are a special form of solvates in which coordination occurs with water. Within the scope of the invention, the solvate is preferably a hydrate.

"Crystalline" as used in the present invention refers to various solid forms formed by the compounds of the present invention, including crystalline forms and amorphous forms.

The "prodrug" of the present invention refers to a compound which is converted into a compound of the present invention by a reaction with an enzyme, gastric acid or the like under physiological conditions of a living body, that is, a compound which is converted into the invention by oxidation, reduction, hydrolysis or the like of the enzyme and/or A compound which is converted into a compound of the invention by a hydrolysis reaction such as gastric acid or the like.

The "alkyl group" of the present invention means a linear or branched saturated hydrocarbon group, preferably a C _1-8 alkyl group, more preferably a C _1-6 alkyl group. Non-limiting examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, 1,1-dimethylpropane 1,1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, 2-methylbutyl, 3-methylbutyl, n-hexyl, 1-ethyl -2-methylpropyl, 1,1,2-trimethylpropyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 2,2-dimethylbutyl, 1,3-Dimethylbutyl, 2-ethylbutyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2,3-dimethylbutyl, n-glycol Base, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, 2,3-dimethylpentyl, 2,4-dimethylpentyl, 2,2- Dimethylpentyl, 3,3-dimethylpentyl, 2-ethylpentyl, 3-ethylpentyl, n-octyl, 2,3-dimethylhexyl, 2,4-dimethyl Hexyl, 2,5-dimethylhexyl, 2,2-dimethylhexyl, 3,3-dimethylhexyl, 4,4-dimethylhexyl, 2-ethylhexyl, 3-ethylhexyl, 4-ethylhexyl, 2-methyl-2-ethylpentyl, 2-methyl-3-ethylpentyl.

"Cycloalkyl" as used in the present invention refers to a saturated or partially unsaturated monocyclic or polycyclic substituent comprising from 3 to 20 carbon atoms, preferably from 4 to 13 carbon atoms. Non-limiting examples of monocycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, cyclohexadienyl, cycloheptyl, cycloheptatriene The group, the cyclooctyl group and the like are preferably a cyclopentyl group or a cyclohexyl group. Polycycloalkyl groups include spiro, fused, and bridged cycloalkyl groups.

The "azacycloalkylene group" of the present invention means a saturated ring comprising a nitrogen atom and a plurality of carbon atoms, and the azacycloalkylene group is preferably aza C _3-20 cycloalkyl group, more preferably aza C _{4 -13} cycloalkyl. More preferably, it is an aza C _3-6 cycloalkyl group. Non-limiting examples of azacycloalkyl groups include pyrrolidinyl and piperidinyl groups.

The "oxyheterocycloalkyl group" of the present invention means a saturated ring composed of one oxygen and a plurality of carbon atoms. The oxacycloalkyl group is preferably an oxa C _3-20 cycloalkyl group, more preferably an oxa C _4-13 cycloalkyl group. More preferably, it is an oxa C _3-6 cycloalkyl group.

The "lactone cycloalkyl group" of the present invention means an ester group

A saturated ring composed of multiple carbon atoms. The lactone cycloalkyl group is preferably a lactone C _3-20 cycloalkyl group, more preferably a lactone C _4-13 cycloalkyl group. More preferred is a lactone C _3-6 cycloalkyl group.

The "alkyl hydroxy group" of the present invention means -alkyl-OH.

The "halogen" of the present invention means fluorine, chlorine, bromine or iodine.

The "amino group" of the present invention means -NH ₂ , -NH(alkyl), -N(alkyl)(alkyl).

The "nitro group" of the present invention means -NO ₂ .

The "cyano group" of the present invention means -CN.

The hydroxy "hydroxy group" of the present invention means -OH.

The "benzyl group" of the present invention means -CH ₂ -phenyl group, abbreviated as "Bn".

"Tert-butoxycarbonyl group" in the present invention means ^{- (O) CO (t Bu} ), abbreviated as "Boc."

The "Fmoc-" of the present invention means a fluorenylmethoxycarbonyl group;

The "amino acid" of the present invention means an amino group-containing carboxylic acid, and the amino group attached to the α-carbon is an α-amino acid, and the structural formula is represented by a CH(COOH)(NH ₂ )- side chain. The "L-amino acid" of the present invention means that the α-carbon atom of the α-amino acid is left-handed; conversely, the "D-amino acid" refers to the α of the general structure CH(COOH)(NH ₂ )-side chain - The carbon atom is right-handed. In addition to glycine, the α-carbon atoms of other protein amino acids are asymmetric carbon atoms (ie, the four substituents bonded to the α-carbon atom are different), so the amino acids may have stereoisomers, ie, may be different Configuration (D-type and L-type two configurations).

Non-limiting examples of amino acids include alanine (Ala), arginine (Arg), asparagine (Asn), aspartic acid (Asp), cysteine (Cys), glutamine (Gln) , glutamic acid (Glu), glycine (Gly), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine Acid (Phe), proline (Pro), serine (Ser), threonine (Thr), tryptophan (Trp), tyrosine (Tyr), valine (Val).

The "amino acid side chain" of the present invention means a component of an amino acid, and the amino acid structural formula is represented by CH(COOH)(NH ₂ )-R, and R represents an amino acid side chain, for example, the structure of alanine is CH (COOH). (NH ₂ )-CH ₃ , the amino acid side chain is -CH ₃ ; the structure of serine is CH(COOH)(NH ₂ )-CH ₂ OH, the amino acid side chain is -CH ₂ OH; the structure of threonine is CH(COOH)(NH ₂ )-CH(OH)(CH ₃ ), the amino acid side chain is -CH(OH)(CH ₃ ).

The "amino acid residue" of the present invention means that a part of the structure is absent compared to the structure of the parent amino acid, and is an incomplete amino acid. For example, a hydrogen atom on the amino group of the amino acid is replaced by a chemical bond to bond with another atom, or an amino acid. -OH is replaced by a chemical bond to bond with other atoms. Such as the structure of alanine

Then its amino acid residue can be

Can also be

The "protecting group" of the present invention is such that the nitrogen atom and the oxygen atom remain unchanged in the reaction of other parts of the molecule, and are protected by a group which is easy to remove. The protecting group of the present invention includes an amino protecting group and a hydroxy protecting group, and the amino protecting group of the present invention means a group which prevents or prevents the amino group from participating in the next reaction until the protecting group is removed, and a non-limiting example includes a formyl group, an alkyl group. Carbonyl, alkoxycarbonyl, benzoyl, aralkylcarbonyl, aralkoxycarbonyl, triphenylmethyl, phthaloyl, N,N-dimethylaminomethylene, substituted monosilane Base, tert-butoxycarbonyl, benzyloxycarbonyl and the like. The hydroxy protecting group of the present invention means a group which prevents or prevents the hydroxyl group from participating in the next reaction until the protecting group is removed. Examples of the hydroxy protecting group include acetyl, allyl, benzoyl, benzyl, β-methoxyethoxymethyl, methoxymethyl, dimethoxytrityl [di-( 4-methoxyphenyl)phenylmethyl], methoxytriphenyl[(4-methoxyphenyl)diphenylmethyl], p-methoxybenzyl ether, methylthiomethyl , trimethylacetyl, tetrahydropyranyl, triphenylmethyl, silicon (eg, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, triiso) Propylsilyloxymethyl and triisopropylsilyl). Other examples include alkyl groups such as methyl and t-butyl groups, as well as other ethers such as ethoxyethyl groups.

detailed description:

The organic solvents used in the following examples are abbreviated as follows:

NMM: N-methylmorpholine;

HATU: 2-(7-oxobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate;

TPP: triphenylphosphine;

HOBT: 1-hydroxybenzotriazole;

EDC: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride;

DAST: diethylaminosulfur trifluoride;

TBDMSCl: tert-butyldimethylchlorosilane;

Fmoc-Asn(Trt)-OH: N-fluorenylmethoxycarbonyl-L-asparagine.

Example 1: ((1-(5-((1S,2S)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)-3-(carboxymethyl) Preparation of cyclobutyl)carbamoyl)-L-serine

Step 1:1 - Preparation of ((tert-Butoxycarbonyl)amino)-3-oxocyclobutane-1-carboxylic acid

Ethyl 1-((tert-butoxycarbonyl)amino)-3-oxocyclobutanecarboxylate (50 mg, 0.19 mmol) was dissolved in methanol (1 mL), water (0.5 mL) Mg, 0.23 mmol), reacted at room temperature for half an hour, and the reaction was monitored by TLC plate (iodine, bromocresol green color development), and the reaction was complete. Methanol was distilled off under reduced pressure, and the remaining liquid was adjusted to pH 4 with 1M citric acid. , Brine and the organic phase was washed with EA and washed with water, dried over anhydrous Na ₂ SO _4. The mixture was evaporated under reduced pressure, and purified by silica gel column (0-50% EA in PE) to yield 40 mg of white solid.

Step 2: Preparation of benzyl 1-((tert-butoxycarbonyl)amino)-3-oxocyclobutane-1-carboxylate

1 - ((tert-butoxycarbonyl) amino) -3-oxo-1 -carboxylic acid (2g, 8.73mmol) was dissolved in DMF (20mL) was added K ₂ CO ₃ (1.81g, 13.09mmol ), BnCl (1.32 g, 10.48 mmol). Placed on a 65 ° C oil bath, heated for 2 h, TLC plate monitoring reaction (iodine smoked color), the reaction is complete. , Brine and the organic phase was washed with EA and washed with water, dried over anhydrous Na ₂ SO _4. The mixture was evaporated under reduced pressure and purified (yield: EtOAc (EtOAc)

Step 3: Preparation of benzyl 1-((tert-butoxycarbonyl)amino)-3-(2-ethoxy-2-oxoethylidene)cyclobutane-1-carboxylate

Benzyl 1-((tert-butoxycarbonyl)amino)-3-oxocyclobutane-1-carboxylate (1 g, 3.13 mmol) was dissolved in toluene (15 mL) and (triphenylphosphine)acetate The ester (1.53 g, 4.38 mmol) was heated under reflux for 4 h, and the reaction was monitored by TLC (yield of iodine) and the reaction was completed. , Brine and the organic phase was washed with EA and washed with water, dried over anhydrous Na ₂ SO _4. The mixture was evaporated under reduced pressure, and purified (yield: EtOAc (EtOAc)

Step 4: Preparation of benzyl 1-amino-3-(2-ethoxy-2-oxoethylidene)cyclobutane-1-carboxylate

Benzyl 1-((tert-butoxycarbonyl)amino)-3-(2-ethoxy-2-oxoethylidene)cyclobutane-1-carboxylate (40 mg, 0.1 mmol) was dissolved in dichloro In a mixed solvent of methane (1 mL) and trifluoroacetic acid (1 mL), the mixture was reacted at room temperature for 2 h, and the reaction was monitored by a TLC plate (yield of iodine), and the reaction was completed. Distillation under reduced pressure to remove excess trifluoroacetic acid was added 20% Na ₂ CO ₃ solution, stirred for 15min, with EA liquid separation, the organic phase was washed with brine, dried over anhydrous Na ₂ SO _4. Distillation under reduced pressure gave a pale yellow oil (yield: 30%).

Step 5: 1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(2-ethoxy-2-oxoethylidene)cyclobutane-1-carboxylic acid Preparation of benzyl ester

Benzyl 1-amino-3-(2-ethoxy-2-oxoethylidene)cyclobutane-1-carboxylate (50 mg, 0.17 mmol) was dissolved in 1,4-dioxane (1 mL) To a mixed solvent of water (0.2 mL), Na ₂ CO ₃ (22 mg, 0.21 mmol) was added, and the mixture was placed in an ice bath, and FmocCl (53.7 mg, 0.21 mmol) was added thereto, and the mixture was gradually warmed to room temperature. After 1 h of reaction, the reaction was monitored by TLC plate (iodine smoked color development) and the reaction was completed. , Brine and the organic phase was washed with EA and washed with water, dried over anhydrous Na ₂ SO _4. The mixture was evaporated under reduced pressure and purified (yield: EtOAc)

Step 6: 1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(2-ethoxy-2-oxoethyl)cyclobutane-1-carboxylic acid preparation

Benzyl 1-((((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(2-ethoxy-2-oxoethylidene)cyclobutane-1-carboxylate (800 mg, 1.56 mmol) was dissolved in MeOH (10 mL). Pd / C (80 mg, 10%, w/w). The Pd/C was removed by filtration through Celite, and the filtrate was evaporated under reduced pressure to yield 496 g of colorless oil.

Step 7: 2-(3-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(2-(N-(tert-butoxy)-O-(tert-butyl) Preparation of ethyl-L-betathreonyl)nonyl-1-carbonyl)cyclobutyl)acetate

1-((((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(2-ethoxy-2-oxoethyl)cyclobutane-1-carboxylic acid (790 mg, 1.86 mmol) was dissolved in DMF (15 mL) and ((2S,3S)-3-(tert-butoxy)-1-indol-1-yloxy-2-yl)carbamic acid tert-butyl ester ( 539 mg, 1.86 mmol), NMM (188.6 mg, 4.65 mmol), HATU (710 mg, 1.86 mmol), reacted at room temperature for 2 h, and the reaction was monitored by TLC plate. The reaction solution was slowly poured into ice water, and a white solid was precipitated, filtered, and washed with water to give a white solid.

Step 8: 2-(3-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(5-((1S,2S)-2-(tert-butoxy)- Preparation of ethyl 1-((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)acetate

2-(3-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(2-(N-(tert-butoxy)-O-(tert-butyl)- Ethyl L-(sub-threonyl) decyl-1-carbonyl)cyclobutyl)acetate (660 mg, 0.95 mmol) was dissolved in a mixed solvent of DMF (8 mL), THF (2 mL) TPP (997mg, 3.8mmol), I 2 (966mg, 3.8mmol), stirred for 30min until complete dissolution of I _2, was added _{Et 3 N (768mg, 7.6mmol)} . After the addition, the ice bath was removed and reacted at room temperature for 3 h. The reaction was monitored by TLC plate and the reaction was complete. Solution with EA and water, the organic phase is washed with saturated sodium thiosulfate, brine, dried over anhydrous Na ₂ SO _4. The mixture was evaporated under reduced pressure and purified by silica gel column (0-25% EA

Step 9: 2-(3-Amino-3-(5-((1S,2S)-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)propyl)-1,3 Of 4-(oxadiazol-2-yl)cyclobutyl)acetate

2-(3-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(5-((1S,2S)-2-(tert-butoxy)-1-) Ethyl ((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)acetate (606 mg, 0.9 mmol) dissolved in DCM (5 mL) ₂ NH (355 mg, 4.85 mmol), reacted at room temperature for 6 h, the reaction was complete. The mixture was evaporated under reduced pressure, and purified (yield: EtOAc)

Step 10: Preparation of O-(tert-butyl)-N-((4-nitrophenoxy)carbonyl)-L-serine tert-butyl ester

The O- (tert-butyl) -L- serine t-butyl ester (10g, 0.046mol, 1.0eq) was dissolved in DCM (200mL), cooled ice bath, added dropwise successively at 0 ℃ Et ₃ N (9.32g, 0.092 A solution of mol 2.0 eq) and phenyl 4-nitrochloroformate (9.25 g, 0.046 mol, 1.0 eq) in DCM (60 mL). The reaction was monitored by TLC plate (iodine) and the reaction was complete. The organic layer was washed three times with saturated Na ₂ CO ₃ , and then adjusted to pH 4 with EtOAc. Dry with anhydrous Na ₂ SO ₄ . Distilled under reduced pressure, washed with petroleum ether, and the product was dissolved in petroleum ether, filtered, and the filtrate was evaporated under reduced pressure to yield 10.5 g of colorless oil.

Step 11: N-((1-(5-((1S,2S)-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxole Preparation of tert-butyl 2-oxazol-2-yl)-3-(2-ethoxy-2-oxoethyl)cyclobutyl)carbamoyl-O-(tert-butyl)-L-serine

2-(3-Amino-3-(5-((1S,2S)-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)propyl)-1,3,4 - oxadiazol-2-yl) cyclobutyl) acetic acid ethyl ester (2.11g, 4.64mmol) was dissolved in DMF (20mL), was added _{Et 3 N (0.93g, 9.28mmol)} , was placed 0 ℃, was added O -(tert-Butyl)-N-((4-nitrophenoxy)carbonyl)-L-serine tert-butyl ester (2.13 g, 5.57 mmol). After the addition, the temperature was raised to room temperature, and reacted at room temperature for 10 hours. The reaction was monitored by TLC plate (iodine), and the reaction was completed. The mixture was evaporated under reduced pressure and purified by silica gel column (0-50% EA in

Step 12: N-((1-(5-((1S,2S)-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxole Preparation of oxazol-2-yl)-3-(carboxy)cyclobutyl)carbamoyl-O-(tert-butyl)-L-serine

N-((1-(5-((1S,2S)-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxadiazole 2-yl)-3-(2-ethoxy-2-oxoethyl)cyclobutyl)carbamoyl-O-(tert-butyl)-L-serine tert-butyl ester (1 g, 1.43 mmol) Dissolved in a mixed solvent of THF (15 mL) and water (5 mL), and placed at 0 ° C, and added LiOH (240 mg, 5.73 mmol), added to room temperature, reacted at room temperature for 5 h, and monitored by TLC plate (iodine). The reaction was completed. The excess THF was distilled off under reduced pressure, and then acidified to pH 4 with 1M citric acid, extracted with dichloromethane, dried over anhydrous Na ₂ SO ₄ , evaporated under reduced pressure and purified by silica gel column (0-5% MeOH in DCM) gave a colorless oil of 150 mg, yield 17%.

Step 13: ((1-(5-((1S,2S)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)-3-(carboxymethyl) Preparation of cyclobutyl)carbamoyl)-L-serine

N-((1-(5-((1S,2S)-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxadiazole 2-yl)-3-(carboxy)cyclobutyl)carbamoyl-O-(tert-butyl)-L-serine (110 mg, 0.179 mmol) was dissolved in DCM (4 mL). , triisopropylsilane (catalytic amount), stirring reaction at room temperature for 5 h. The reaction solution was spun dry, added DCM, water, liquid separation, the organic phase was extracted several times with water, the aqueous phase was combined, washed several times with DCM, lyophilized , preparative separation, 16mg white solid; ^{yield:. 22.2% 1 H NMR (} 500MHz, D 2 O): δ4.73 (d, J = 6.4Hz, 1H), 4.49-4.39 (m, 1H), 4.19 (t, J = 4.5 Hz, 1H), 3.89 (dd, J = 10.5, 4.5 Hz, 2H), 3.11 - 2.97 (m, 1H), 2.73 (t, J = 10.8 Hz, 2H), 2.56 (t, J=7.4 Hz, 4H), 1.40 (s, 3H). ESI-MS m/z: 402.2 [M+H] ⁺

Example 2: ((1-(5-((1S,2S)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)-3-(2-B) Preparation of oxy-2-oxoethyl)cyclobutyl)carbamoyl)-L-serine

synthetic route:

N-((1-(5-((1S,2S)-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxadiazole 2-yl)-3-(2-ethoxy-2-oxoethyl)cyclobutyl)carbamoyl-O-(tert-butyl)-L-serine tert-butyl ester (200 mg, 0.28 mmol) Dissolve in DCM (2mL), add TFA (2.1mL), triisopropylsilane (catalytic amount) at room temperature, stir the reaction at room temperature for 5h. Dissolve the reaction solution, add DCM, water, separate the liquid, extract the organic phase several times with water The aqueous phase was combined and washed with DCM several times, lyophilized and purified to give a white solid (yield: 48 mg, yield: 48.8%) ¹ H NMR (400 MHz, D ₂ O): δ 4.51 (dd, J = 8.7, 6.3 Hz, 1H), 4.22 (dd, J = 12.7, 6.4 Hz, 1H), 4.05 (q, J = 7.1 Hz, 2H), 3.97 (dt, J = 13.6, 4.7 Hz, 1H), 3.69 (dd, J = 8.5, 4.7 Hz, 2H), 2.87 (ddd, J = 17.7, 14.4, 8.4 Hz, 1H), 2.61 - 2.51 (m, 3H), 2.48 - 2.33 (m, 1H), 2.25 - 2.13 (m, 1H) ), 1.19 (dd, J = 6.4, 2.7 Hz, 3H), 1.14 (t, J = 7.1 Hz, 3H). ESI-MS m/z: 430.2 [M+H] ⁺

Example 3: ((1-(5-((1S,2S)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)-3-(2-amino) Preparation of -2-oxoethyl)cyclobutyl)carbamoyl)-L-serine

Step 1: Preparation of ethyl 3-(2-amino-2-oxoethylidene)-1-((tert-butoxycarbonyl)amino)cyclobutane-1-carboxylate

NaH (676 mg, 0.016 mol, 1.1 eq) was dissolved in 10 mL of DMF, placed in a -20 ° C low temperature reactor, and a solution of diethyl carbamoylphosphonate (3 g, 0.015 mol) in DMF was added. After stirring for 1 h, ethyl 1 -((tert-butoxycarbonyl)amino)-3-oxocyclobutanecarboxylate (3.56 g, 0.013 mol) was added dropwise dropwise, and the reaction was continued for 4 hours, TLC plate. The reaction was monitored (iodine) and the reaction was complete. The organic layer was washed twice with saturated brine and dried over anhydrous Na ₂ SO ₄ . The mixture was evaporated under reduced pressure and purified (yield: EtOAc) (yield:

Step 2: Preparation of ethyl 3-(2-amino-2-oxoethyl)-1-((tert-butoxycarbonyl)amino)cyclobutane-1-carboxylate

The title compound was obtained according to the procedure of Step 6 in Example 1, except that the starting material was 1-((((())))))))))) Replacement of benzyl 2-oxoethylidene)cyclobutane-1-carboxylate with 3-(2-amino-2-oxoethylidene)-1-((tert-butoxycarbonyl)amino) ring Butane-1-carboxylate.

Step 3: Preparation of 3-(2-amino-2-oxoethyl)-1-((tert-butoxycarbonyl)amino)cyclobutanecarboxylic acid

Ethyl ethyl 3-(2-amino-2-oxoethyl)-1-((tert-butoxycarbonyl)amino)cyclobutanecarboxylate (3.03 g, 0.01 mol) was dissolved in THF (EtOAc) Add LiOH aqueous solution (508 mg, 0.012 mol,), react at room temperature for 5 h, distill off under reduced pressure, remove excess THF, adjust pH to 2 with 1 M citric acid, freeze-dry, and purify on silica gel column (0-10% MeOH in DCM) The obtained product is directly put into the next reaction.

Step 4: 3-(2-Amino-2-oxoethyl)-1-carboxycyclobutylamine hydrochloride

The crude 3-(2-amino-2-oxoethyl)-1-((tert-butoxycarbonyl)amino)cyclobutanecarboxylic acid (190 mg, 0.69 mmol) was dissolved in 2 mL of 1.5M EtOAc The reaction was carried out for 3 h at room temperature. Distillation under reduced pressure gave a crude product (132 mg, yield: 91%).

Step 5: ((1-(5-((1S,2S)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)-3-(2-amino-) Preparation of 2-oxoethyl)cyclobutyl)carbamoyl)-L-serine

The title compound was obtained according to the procedure of Steps 5, 7, 8, 9, 11, and 13 in Example 1, except that the starting material in the step 5 was 1-amino-3-(2-ethoxy-2-oxo Benzylene) benzyl cyclobutanecarboxylate (50 mg, 0.17 mmol) was dissolved in 1,4-dioxane to 3-(2-amino-2-oxoethyl)-1-carboxycyclobutylamine Hydrochloride. ¹ H NMR (400 MHz, D ₂ O): δ 4.21 - 4.11 (m, 2H), 3.89 (d, J = 6.4 Hz, 1H), 3.81 (dd, J = 6.0, 2.4 Hz, 2H), 2.97 - 2.72 (m, 2H), 2.69 (dd, J = 11.6, 5.1 Hz, 2H), 2.58 - 2.29 (m, 2H), 2.09 (ddd, J = 31.0, 12.2, 7.5 Hz, 1H), 1.37 (t, J=5.7 Hz, 3H). ESI-MS m/z: 401.3 [M+H] ⁺

Example 4: (((1s,3R)-1-(5-((1S,2S)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)-) Preparation of 3-(cyanomethyl)cyclobutyl)carbamoyl)-L-serine

Preparation of ethyl 1-((tert-butoxycarbonyl)amino)-3-(cyanomethylene)cyclobutanecarboxylate

The title compound was obtained in a similar manner to the method of the step 3 in Example 1, except that the starting material (triphenylphosphine) ethyl acetate was replaced with (triphenylphosphine) acetonitrile.

Step 2: Preparation of (1s,3s)-1-((tert-butoxycarbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylate

Preparation Method The method of the step 6 in Example 1, except that the starting material benzyl 1-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-(2-ethoxyl) -2-oxoethylidene)cyclobutanecarboxylate is replaced by ethyl 1-((tert-butoxycarbonyl)amino)-3-(cyanomethylene)cyclobutanecarboxylate obtained in the above step 1, The title compound and its stereoisomer were obtained by column chromatography after workup.

Step 3: Preparation of (1s,3s)-1-((tert-butoxycarbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylic acid

The title compound was obtained according to the procedure of Step 3 in Example 3, except that the starting material ethyl 3-(2-amino-2-oxoethyl)-1-((tert-butoxycarbonyl)amino)cyclobutane The ethyl alkanoate was replaced with the ethyl ester of (1s, 3s)-1-((tert-butoxycarbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylate obtained in the above step 2.

Step 4: Preparation of (1s,3s)-1-cyano-3-(cyanomethyl)cyclobutylamine hydrochloride

(1s,3s)-1-((tert-Butoxycarbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylic acid (1.4 g, 5.5 mmol, 1.0 eq) was dissolved in 8 mL of 1,4-dioxane To the ring, 14 mL of a HCl solution of 1,4-dioxane was added, and the mixture was reacted overnight, and filtered to give a white solid, 1.04 g, yield 100%.

Step 5: (((1s,3R)-1-(5-((1S,2S)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)-3 Preparation of -(cyanomethyl)cyclobutyl)carbamoyl)-L-serine

The title compound was obtained according to the procedure of Steps 5, 7, 8, 9, 11, and 13 in Example 1, except that the starting material of the first step of Example 1 was 1-amino-3-(2-ethoxy- The benzyl 2-oxoethylidenecyclobutanecarboxylate was replaced with the product of the above step 4 (1s, 3s)-1-cyano-3-(cyanomethyl)cyclobutylamine hydrochloride. ¹ H NMR (400 MHz, D ₂ O): δ 4.75 (d, J = 6.5 Hz, 1H), 4.37 (p, J = 6.4 Hz, 1H), 4.30 (t, J = 4.3 Hz, 1H), 3.94 (dd, J=11.7, 4.8 Hz, 1H), 3.85 (dd, J=11.6, 4.0 Hz, 1H), 2.99 (ddt, J=16.9, 8.1, 4.6 Hz, 2H), 2.86 (tt, J=13.6) , 6.9 Hz, 1H), 2.77 (d, J = 6.4 Hz, 2H), 2.46 - 2.35 (m, 2H), 1.33 (d, J = 6.5 Hz, 3H). ESI-MS m/z: 383.1 [M +H] ⁺

Example 5: (((1r,3S)-1-(5-((1S,2S)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)- Preparation of 3-(cyanomethyl)cyclobutyl)carbamoyl)-L-serine

Another conformational isomer of ethyl (1s,3s)-1-((tert-butoxycarbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylate prepared in Step 2 of Example 4 For the starting materials, the title compound was obtained by the procedure of Step 3-5 in Example 4. ¹ H NMR (400 MHz, D ₂ O): δ 4.75 (d, J = 6.5 Hz, 1H), 4.37 (p, J = 6.4 Hz, 1H), 4.30 (t, J = 4.3 Hz, 1H), 3.94 (dd, J=11.7, 4.8 Hz, 1H), 3.85 (dd, J=11.6, 4.0 Hz, 1H), 2.99 (ddt, J=16.9, 8.1, 4.6 Hz, 2H), 2.86 (tt, J=13.6) , 6.9 Hz, 1H), 2.77 (d, J = 6.4 Hz, 2H), 2.46 - 2.35 (m, 2H), 1.33 (d, J = 6.5 Hz, 3H). ESI-MS m/z: 383.1 [M +H] ⁺ .

Example 6: ((1-(3-((R)-1-Amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3-(carboxymethyl) ring Preparation of butyl)carbamoyl)-L-pyrethine

Step 1: 1 - Preparation of ((benzyloxy)carbonyl)-3-oxocyclobutaneamine hydrochloride

The title compound was obtained according to the procedure of Step 4 in Example 4, except that starting material (1s, 3s)-1-((tert-butoxycarbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylic acid Replaced with benzyl 1-((tert-butoxycarbonyl)amino)-3-oxocyclobutanecarboxylate.

Step 2: Preparation of benzyl 1-((((9H-芴-9-yl)methoxy)carbonyl)amino)-3-oxocyclobutanecarboxylate

The title compound was obtained according to the procedure of Step 5 in Example 1, except that the starting material of the starting material of Example 1 was 1-amino-3-(2-ethoxy-2-oxoethylidene)cyclobutane. The benzyl carbamate was replaced with the 1-((benzyloxy)carbonyl)-3-oxocyclobutaneamine hydrochloride obtained in the above step 1.

Step 3: Benzyl 1-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-(2-(tert-butoxy)-2-oxoethylidene)cyclobutane Preparation of alkacrylate

Benzyl 1-(((((9H-芴-9-yl)methoxy)carbonyl)amino)-3-oxocyclobutanecarboxylate (300 mg, 0.68 mmol) was dissolved in toluene (5 mL) (tert-Butoxycarbonylmethylene)triphenylphosphorate (282 mg, 0.74 mmol), placed in an oil bath at 50 ° C, reacted for 24 h, distilled under reduced pressure, EA and aqueous solution, washed with brine, anhydrous Na ₂ SO _{4 was} dried, distilled under reduced pressure, and purified by silica gel column (0-10% EAIN PE) to afford 263 mg of colorless oil.

Step 4: 1-(((9H-Indol-9-yl)methoxy)carbonyl)amino)-3-(2-(tert-butoxy)-2-oxoethyl)cyclobutanecarboxylic acid preparation

The title compound was obtained according to the procedure of Step 6 in Example 1, except that the starting material benzyl 1-((((9H- -9) yl)) oxy)) Ethoxy-2-oxoethylidene)cyclobutanecarboxylate is replaced by the benzyl 1-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)- 3-(2-(tert-Butoxy)-2-oxoethylidene)cyclobutanecarboxylate.

Step 5: (R,Z)-2-(3-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(4-amino-5-(tert-butoxymethyl) Of tert-butyl 9-dimethyl-7-oxo-2,8-dioxa-3,6-diazacyclo-3-ene-1-yl)cyclobutyl)acetate

1-((((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(2-(tert-butoxy)-2-oxoethyl)cyclobutanecarboxylic acid (1.51 g) , 3.34 mmol), dissolved in DMF (20 mL), EtOAc (EtOAc m. the reaction mixture was slowly poured into ice water, the precipitated solid was filtered, washed with water, the crude product was dissolved in ethyl acetate, separated, the organic phase was dried over anhydrous Na ₂ SO _4. Distillation under reduced pressure gave a white solid 1.6 g, yield 67.5%

Step 6: (R)-2-(3-((((9H-芴-9-yl))methoxy)carbonyl)amino)-3-(3-(2-(tert-butoxy)-1) Preparation of tert-butyl (-(tert-butoxycarbonyl)amino)ethyl)-1,2,4-oxadiazol-5-yl)cyclobutyl)acetate

(R,Z)-2-(3-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(4-amino-5-(tert-butoxymethyl)) Tert-butyl 9-dimethyl-7-oxo-2,8-dioxa-3,6-diazacyclo-3-ene-1-yl)cyclobutyl)acetate (1.6 g, 2.27 mmol) was dissolved in a mixed solvent of ethanol (40 mL) and water (4 mL), and sodium acetate (280 mg, 3.4 mmol) was added, and the mixture was heated to reflux for 10 h. Distilled under reduced pressure, ethyl acetate and water were evaporated, washed with saturated brine, and dried over anhydrous sodium sulfate. The rate is 52%.

Step 7: ((1-(3-((R)-1-Amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3-(carboxymethyl)cyclobutane Preparation of carbamoyl)-L-pyrethine

The title compound was obtained according to the procedure of Steps 9, 11, 13 in Example 1, except that the starting material ethyl 2-(3-(((((((()))))))) -3(5-((1S,2S)-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxadiazole-2 -()-cyclobutyl)acetate is replaced by the above-mentioned step 6 (R)-2-(3-(((9H-芴-9-yl))methoxy)carbonyl)amino)-3-( Tert-butyl 3-(2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)ethyl)-1,2,4-oxadiazol-5-yl)cyclobutyl)acetate preparation. ¹ H NMR (400 MHz, D ₂ O): δ 4.73 (dd, J = 8.5, 4.3 Hz, 1H), 4.38 - 4.29 (m, 1H), 4.17 (dd, J = 10.0, 2.3 Hz, 1H), 4.15–4.01 (m, 2H), 2.95 (dt, J = 16.5, 8.4 Hz, 1H), 2.81 (dt, J = 15.8, 8.0 Hz, 0.5H), 2.69–2.47 (m, 5H), 2.35–2.17 (m, 0.5H), 1.17 (t, J = 6.9 Hz, 3H). ESI-MS m/z: 402.2 [M+H] ⁺

Example 7: ((1-(3-((R)-1-Amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3-(2-amino-2) -Oxoethyl)cyclobutyl)carbamoyl)-L-pyrethine

Step 1: (R)-(1-(5-(1-(((9H-芴-9-yl))methoxy)carbonyl)amino)-3-(3-(2-amino-2-oxo) Preparation of tert-butyl ester of ethyl)cyclobutyl)-1,2,4-oxadiazol-3-yl)-2-(tert-butoxy)ethyl)carbamate

The title compound was obtained according to the procedure of Steps 5 and 6 in Example 6 except that the starting material was 1-((((9H-in-9-yl)methoxy)carbonyl)amino)-3-(2-) Replacement of (tert-butoxy)-2-oxoethyl)cyclobutanecarboxylic acid with 3-(2-amino-2-oxoethyl)-1-((tert-butoxycarbonyl)amino)cyclobutane Formic acid.

Step 2: ((1-(3-((R)-1-Amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3-(2-amino-2-) Preparation of oxoethyl)cyclobutyl)carbamoyl)-L-pyrethine

The title compound was obtained by the procedure of Steps 9, 11, and 13 in Example 1. The difference is that the starting material is 2-(3-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(5-((1S,2S)-2-(tert-butoxy) -1 -((tert-Butoxycarbonyl)amino)propyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)acetate was replaced by (R)-(1-(5) -(1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(3-(2-amino-2-oxoethyl)cyclobutyl)-1,2,4 tert-Butyl oxazol-3-yl)-2-(tert-butoxy)ethyl)carbamate ¹ H NMR (400 MHz, D ₂ O): δ 4.41 - 4.32 (m, 1H), 4.22 (dt, J=9.5, 3.3 Hz, 1H), 4.18–4.03 (m, 2H), 3.06–2.78 (m, 2H), 2.68–2.49 (m, 4H), 2.29 (ddd, J=12.0, 8.5, 3.4 Hz, 1H), 1.21 (t, J = 6.6 Hz, 3H). ESI-MS m/z: 401.2 [M+H] ⁺

Example 8: (((1r,3S)-1-(3-((R)-1-Amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3- Preparation of (cyanomethyl)cyclobutyl)carbamoyl)-L-pyrethine

Step 1: Preparation of (9H-fluoren-9-yl)methyl-((1r,3r)-3-(cyanomethyl)-1-(fluorocarbonyl)cyclobutyl)carbamate

1-((((9H-Indol-9-yl)methoxy)carbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylic acid (200 mg, 0.53 mmol) was added DAST (111mg, 0.69mmol), stirred at rt for 1h ,, the reaction was quenched with water, dichloromethane and extracted with water, the organic layer was washed with saturated brine, dried Na ₂ SO _4. The mixture was distilled under reduced pressure, and the resultant was directly poured into the next reaction.

Step 2: ((R)-1-(5-((1r,3R)-1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(cyanomethyl) Of tert-butyl)-1,2,4-oxadiazol-3-yl)2-(tert-butoxy)ethyl)carbamic acid tert-butyl ester

The title compound was obtained according to the procedure of Steps 5 and 6 in Example 6 except that the starting material was 1-((((9H-in-9-yl)methoxy)carbonyl)amino)-3-(2-) Replacement of (tert-butoxy)-2-oxoethyl)cyclobutanecarboxylic acid with (9H-fluoren-9-yl)methyl(3-(cyanomethyl)-1-(fluorocarbonyl)cyclobutane Carbamate.

Step 3: (((1R,3S)-1-(3-((R)-1-Amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3-( Preparation of cyanomethyl)cyclobutyl)carbamoyl)-L-pyrethine

The title compound was obtained by the procedure of Steps 9, 11, and 13 in Example 1. The difference is that the starting material is 2-(3-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(5-((1S,2S)-2-(tert-butoxy) ) ethyl-1-((tert-butoxycarbonyl)amino)propyl)-1,3,4-oxadiazol-2-yl)cyclobutyl)acetate was replaced by ((R)-1-(5) -((1r,3R)-1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-3-(cyanomethyl)cyclobutyl)-1,2,4- Tert-butyl ester of oxadiazol-3-yl)2-(tert-butoxy)ethyl)carbamate. ¹ H NMR (400 MHz, D ₂ O): δ 4.65 - 4.56 (m, 1H), 4.21. (qd, J = 6.4, 2.7 Hz, 1H), 4.12 - 4.03 (m, 1H), 3.99 - 3.83 (m) , 2H), 2.93 - 2.73 (m, 1H), 2.58 (t, J = 8.6 Hz, 2H), 2.50 (d, J = 8.7 Hz, 3H), 1.05 (d, J = 6.4 Hz, 3H). ESI -MS m/z: 383.2 [M+H] ⁺

Example 9: (((1s,3R)-1-(5-((S)-1-Amino-2-hydroxyethyl)-1,3,4-oxadiazol-2-yl)-3- Preparation of (cyanomethyl)cyclobutyl)carbamoyl)-L-pyrethine

Tert-butyl (S)-(3-(tert-butoxy)-1-indol-1-ylpropan-2-yl)carbamate and 1-((((9H-芴-9-yl))) The title compound was obtained by the procedure of Steps 7, 8, 9, 11, and 13 of Example 1, using methoxy)carbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylic acid as the starting material.

Example 10: (((1r,3S)-1-(5-((S)-1-Amino-2-hydroxyethyl)-1,3,4-oxadiazol-2-yl)-3- Preparation of (cyanomethyl)cyclobutyl)carbamoyl)-L-pyrethine

Taking another conformational isomer of 1-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-(cyanomethyl)cyclobutanecarboxylic acid as a raw material, according to the example The title compound was obtained by the method of Steps 7, 8, 9, 11, and 13 in 1.

Example 11 (((S)-4-Amino-1-(5-((2S,4R)-4-hydroxytetrahydropyrrole-2-yl)-1,3,4-oxadiazol-2-yl) )-4-oxobutyl)carbamoyl)-L-serine

Step 1 Preparation of (2S,4R)-N-(tert-Butoxycarbonyl)-4-((tert-butyldimethylsilyl)oxy)-2-pyrrolecarboxylic acid methyl ester

Methyl (2S,4R)-N-(tert-butoxycarbonyl)-4-hydroxy-2-pyrrolecarboxylate (5 g, 20.4 mmol, 1 eq) and imidazole (1.7 g, 24.5 mmol, 1.2 eq) were dissolved in N. To N-dimethylformamide (70 mL), tert-butyldimethylsilyl chloride (3.7 g, 24.5 mmol, 1.2 eq) was added to the solution at 0 ° C and stirred at room temperature for about 24 h. After the reaction is completed, a saturated ammonium chloride solution and ethyl acetate are added to the mixed solution, and the organic phase is washed successively with a saturated aqueous solution of ammonium chloride, water and a saturated sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated. The product was obtained as a clear oil (6.0 g).

Step 2 Preparation of (2S,4R)-4-((tert-butyldimethylsilyl)oxy)-2-(indolylcarbonyl)tetrahydropyrrole-1-carboxylic acid tert-butyl ester

Methyl (2S,4R)-N-(tert-butoxycarbonyl)-4-((tert-butyldimethylsilyl)oxy)-2-pyrrolecarboxylate (6 g, 16.7 mmol) obtained in Step 1 Dissolved in methanol (36 mL), and added hydrazine hydrate (15 mL). After the reaction is completed, the methanol is evaporated to dryness. Water and ethyl acetate are added to the mixture. The organic phase is washed with water, washed with saturated sodium chloride, dried over anhydrous sodium sulfate, filtered, The yield was 91.7%.

Step 3 (2S,4R)-2-(2-(N ² -((9H-芴-9-yl)methoxy)carbonyl)-N ⁵ -trityl-L-glutaminyl) Preparation of tert-butyl ester of mercapto-1-carbonyl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-1-carboxylate

(2S,4R)-4-((tert-Butyldimethylsilyl)oxy)-2-(indolylcarbonyl)tetrahydropyrrole-1-carboxylic acid tert-butyl ester (5.5 g, 15.3 mmol, 1 eq) , N ² -(((9H-芴-9-yl)methoxy)carbonyl)-N ⁵ -trityl-L-glutamine (9.4 g, 15.3 mmol, 1 eq), 1-ethyl- (3-Dimethylaminopropyl)carbodiimide hydrochloride (3.5 g, 18.4 mmol, 1.2 eq), 1-hydroxybenzotriazole (2.5 g, 18.4 mmol, 1.2 eq) dissolved in N, N-methylmorpholine (3.9 g, 38.2 mmol, 2.5 eq) was slowly added dropwise to N-dimethylformamide (50 mL) at 0 ° C, and the mixture was stirred at room temperature for 12 h. After the reaction is completed, the mixed solution is poured into ice water, stirred, and the solid is precipitated, suction filtered, and the solid is dissolved with dichloromethane, the aqueous phase is separated, the organic phase is dried over anhydrous sodium sulfate, dried, and petroleum ether is added thereto. Filtration and solid drying gave a white solid (14.1 g).

Step 4 (2S,4R)-2-(5-((S)-1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-4-oxo-4-(3) Benzylamino)butyl)-1,3,4-oxadiazol-2-yl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-1-carboxylic acid tert-butyl ester Preparation

(2S,4R)-2-(2-(N ² -((9H-芴-9-yl)methoxy)carbonyl)-N ⁵ -trityl-L-glutaminyl) tert-Butyl benzyl-1-carbonyl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-1-carboxylate (14.1 g, 14.8 mmol, 1 eq) dissolved in tetrahydrofuran (100 mL) and N Triphenylphosphine (7.9 g, 30.1 mmol, 2 eq) and iodine (7.6 g, 30.1 mmol, 2 eq) were added at 0 ° C in N-dimethylformamide (40 mL). After the iodine was completely dissolved, triethylamine (5.9 g, 58.6 mmol, 4 eq) was added, and the mixture was stirred at room temperature for 5 h. After the reaction is completed, water and ethyl acetate are added to the mixed solution, and the organic phase is washed with a sodium thiosulfate solution and a saturated sodium chloride solution, dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography. Ethyl acetate: petroleum ether = 1:3). A white solid (4.8 g) was obtained in a yield of 34.7%.

Step 5 (2S,4R)-2-(5-((S)-1-Amino-4-oxo-4-(tritylamino)butyl)-1,3,4-oxadiazole- Preparation of 2-butyryl-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-1-carboxylic acid tert-butyl ester

(2S,4R)-2-(5-((S)-1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-4-oxo-4-(triphenyl) Methylamino)butyl)-1,3,4-oxadiazol-2-yl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-1-carboxylic acid tert-butyl ester ( 3 g, 3.2 mmol) was dissolved in dichloromethane (15 mL). After the reaction was completed, the mixture was concentrated and purified by column chromatography (ethyl acetate: petroleum ether = 4:1). A white solid (1.7 g) was obtained in a yield of 74.2%.

Step 6 Preparation of O-(tert-butyl)-N-((4-nitrophenoxy)carbonyl)-L-serine tert-butyl ester

O-(tert-butyl)-L-serine tert-butyl ester (5 g, 23.01 mmol, 1 eq) was dissolved in dichloromethane (25 mL) and triethylamine (4.7 g, 46.02 mmol, 2 eq) 4-Nitrophenyl chloroformate (5.1 g, 25.31 mmol, 1.1 eq) was slowly added dropwise to a solution of dichloromethane (25 mL). After the reaction is completed, citric acid and dichloromethane are added, the organic phase is washed with citric acid, saturated sodium carbonate solution, water, dried, concentrated, washed with petroleum ether, suction filtered, and the filtrate is dried to give a white solid (2.2 g) The yield was 25.0%.

Step 7 (2S,4R)-2-(5-((6S,10S)-10-(tert-butoxymethyl)-13,13-dimethyl-3,8,11-trioxo-1, 1,1-triphenyl-12-oxy-2,7,9-azatetradecane-6-yl)-1,3,4-oxadiazol-2-yl)-4-((uncle Preparation of tert-butyl butyl dimethylsilyl)oxy)tetrahydropyrrole-1-carboxylate

(2S,4R)-2-(5-((S)-1-Amino-4-oxo-4-(tritylamino)butyl)-1,3,4-oxadiazole-2 -yl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-1-carboxylic acid tert-butyl ester (0.7 g, 0.98 mmol, 1 eq) and triethylamine (0.2 g, 1.97 mmol, 2 eq) was dissolved in N,N-dimethylformamide (15 mL), and O-(tert-butyl)-N-((4-nitrophenoxy)carbonyl)-L-serine was added dropwise at 0 °C. tert-Butyl ester (0.41 g, 1.08 mmol, 1.1 eq) was stirred at room temperature for 6 h. After the reaction is completed, dichloromethane and water are added, and the organic phase is washed with water, saturated sodium chloride solution, dried over anhydrous sodium sulfate, filtered, filtered, and purified by column chromatography (ethyl acetate: petroleum ether = 2: 3) A white solid (0.8 g) was obtained in a yield of 85.2%.

Step 8 (((S)-4-Amino-1-(5-((2S,4R)-4-hydroxytetrahydropyrrole-2-yl)-1,3,4-oxadiazol-2-yl) Preparation of -4-oxobutyl)carbamoyl)-L-serine

(2S,4R)-2-(5-((6S,10S)-10-(tert-butoxymethyl)-13,13-dimethyl-3,8,11-trioxo-1,1 ,1-triphenyl-12-oxy-2,7,9-azatetradecane-6-yl)-1,3,4-oxadiazol-2-yl)-4-((tert-butyl) tert-Butyl dimethylsilyl)oxy)tetrahydropyrrole-1-carboxylate (800 mg, 0.84 mmol) was dissolved in dichloromethane (16 mL), trifluoroacetic acid (16 mL) and triisopropylsilane (0.8) (mL), stir at room temperature for 6 h. After the reaction was completed, the mixture was evaporated to dryness, water and methylene chloride, and the aqueous phase was washed with methylene chloride, and lyophilized to give a white solid (190 mg). ¹ H NMR (400 MHz, D ₂ O): δ 5.35-5.31 (t, 1H), 5.11-5.08 (t, 1H), 4.87-4.73 (m, 1H), 4.19 - 4.17 (t, 1H), 3.89 -3.83(d,2H), 3.70-3.66(t,1H),3.53-3.50(t,1H),2.69-2.60(m,2H),2.56-2.52(t,2H),2.44-2.37(m, 1H), 2.30-2.23 (m, 1H). ESI-MS m/z: 387.0 [M+H] ⁺ .

Example 12 (((S)-4-Amino-1-(5-((2S,3S)-3-hydroxytetrahydropyrrole-2-yl)-1,3,4-oxadiazol-2-yl) Preparation of 4-oxobutyl)carbamoyl)-L-serine

Step 1 Preparation of (2S,3S)-3-hydroxytetrahydropyrrole-2-carboxylic acid methyl ester

(2S,3S)-3-Hydroxytetrahydropyrrole-2-carboxylic acid (4 g, 30.5 mmol, 1 eq) was dissolved in methanol (40 mL), and chlorosulfoxide (5.44 g, 45.8 mmol, 1.5) was added dropwise at 0 °C. Eq), after the completion of the dropwise addition, the mixed solution was refluxed at 65-70 ° C for 3 h, and after the reaction was completed, it was dried to give a product (yield: 4.4 g).

Step 2 Preparation of (2S,3S)-N-(tert-Butoxycarbonyl)-3-hydroxy-2-pyrrolecarboxylic acid methyl ester

Methyl (2S,3S)-3-hydroxytetrahydropyrrole-2-carboxylate (4.4 g, 30.3 mmol, 1 eq) was dissolved in tetrahydrofuran (40 mL), and aqueous sodium hydrogencarbonate (8.9 g, 106.1 Methyl acetate (3.5 eq, dissolved in 40 mL of water) and di-tert-butyl dicarbonate (6.28 g, 28.8 mmol, 0.95 eq) was added dropwise at 0 ° C, and then stirred at room temperature for 24 h. Water and ethyl acetate were added to the mixture, and the mixture was evaporated.

Step 3 (((S)-4-Amino-1-(5-((2S,3S)-3-hydroxytetrahydropyrrole-2-yl)-1,3,4-oxadiazol-2-yl) Preparation of -4-oxobutyl)carbamoyl)-L-serine

The preparation method is the same as the preparation method of Step 1 to Step 8 in Example 11, except that the starting material (2S, 4R)-N-(tert-butoxycarbonyl)-4-hydroxy-2-pyrrolecarboxylic acid A in Example 11 is prepared. The ester was replaced with the product of the above step 2 (2S,3S)-N-(tert-butoxycarbonyl)-3-hydroxy-2-pyrrolecarboxylic acid methyl ester. ¹ H NMR (400 MHz, D ₂ O): δ 5.12 - 5.10 (t, 1H), 5.09 - 5.06 (t, 1H), 4.95 - 4.94 (m, 1H), 4.20 - 4.19 (t, 1H), 3.87 -3.86(d,2H), 3.78-3.73(t,2H), 2.58-2.53(t,2H),2.53-2.48(m,1H), 2.47-2.37(m,1H), 2.29-2.22(m, 2H). ESI-MS m/z: 387.0 [M+H] ⁺ .

Example 13 (2S,4R)-1-(((S)-4-amino-1-(5-((1S,2R)-1-amino-2-hydroxypropyl)-1,3,4- Preparation of oxadiazol-2-yl)-4-oxobutyl)carbamoyl)-4-hydroxytetrahydropyrrole-2-carboxylic acid

Step 1 Preparation of N-(tert-Butoxycarbonyl)-O-(tert-butyl)-L-threonine methyl ester

N-(tert-Butoxycarbonyl)-O-(tert-butyl)-L-threonine (5 g, 18.2 mmol, 1 eq) was dissolved in N,N-dimethylformamide (35 mL). Methyl iodide (2.8 g, 20.0 mmol, 1.1 eq), potassium carbonate (7.9 g, 54.5 mmol, 3 eq) was added and stirred at room temperature for about 3 h. After the reaction was completed, water and ethyl acetate were added to the mixture, and the mixture was evaporated. 99.0%.

Step 2 Preparation of (2S,3R)-3-(tert-butoxy)-1-indolyl-1-oxobutan-2-yl)carbamic acid tert-butyl ester

N-(tert-Butoxycarbonyl)-O-(tert-butyl)-L-threonine methyl ester (5.2 g, 18.0 mmol) was dissolved in methanol, and hydrazine hydrate (15 mL) was added to the solution and stirred at room temperature. 24h. After the reaction was completed, the methanol was evaporated to dryness. EtOAc was evaporated. The yield was 100.0%.

Step 3 ((5S,10S,11R)-1-(9H-芴-9-yl)-11,13,13-trimethyl-3,6,9-trioxo-5-(3-oxo Preparation of tert-butyl 3-(tritylmethylamino)propyl)-2,12-dioxa-4,7,8-triazatetradecane-10-yl)carbamate

tert-Butyl ((2S,3R)-3-(tert-butoxy)-1-indolyl-1-oxobutan-2-yl)carbamate (5.2 g, 18.0 mmol, 1 eq), N2- ( ((9H-芴-9-yl)methoxy)carbonyl)-N5-trityl-L-glutamine (11.0 g, 18.0 mmol, 1 eq), 1-ethyl-(3-dimethyl Aminopropyl)carbodiimide hydrochloride (4.1 g, 21.6 mmol, 1.2 eq), 1-hydroxybenzotriazole (2.9 g, 21.6 mmol, 1.2 eq) dissolved in N,N-dimethyl N-methylmorpholine (4.5 g, 44.9 mmol, 2.5 eq) was slowly added dropwise to the amide (40 mL) at 0 ° C, and the mixture was stirred at room temperature for 12 h. After the reaction was completed, the mixed solution was poured into ice water and stirred, and the solid was precipitated and suction filtered. The solid was dissolved in dichloromethane, the aqueous phase was separated, dried, evaporated, evaporated, evaporated, evaporated,

Step 4 ((1S,2R)-1-(5-((S)-1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-4-oxo-4-() Preparation of tert-butyl ester of tritylamino)butyl)-1,3,4-oxadiazol-2-yl)-2-(tert-butoxy)propyl)carbamate

((5S,10S,11R)-1-(9H-芴-9-yl)-11,13,13-trimethyl-3,6,9-trioxo-5-(3-oxo- tert-Butyl 3-(tritylamino)propyl)-2,12-dioxa-4,7,8-triazatetradecane-10-yl)carbamate (10.5 g, 11.9 mmol, 1 eq) was dissolved in tetrahydrofuran (75 mL) and N,N-dimethylformamide (30 mL), and triphenylphosphine (6.2 g, 23.8 mmol, 2 eq) and iodine (6.0 g, 23.8 mmol, 2eq). After the iodine was completely dissolved, triethylamine (4.8 g, 47.6 mmol, 4 eq) was added, and the mixture was stirred at room temperature for 5 h. After the reaction is completed, water and ethyl acetate are added to the mixed solution, and the organic phase is washed with a saturated sodium thiosulfate solution and a saturated sodium chloride solution, dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography. White solid (3.9 g), yield 38.0%.

Step 5 ((1S,2R)-1-(5-((S)-1-Amino-4-oxo-4-(tritylamino)butyl)-1,3,4-oxadiazole Preparation of tert-butyl 2-yl)-2-(tert-butoxy)propyl)carbamate

((1S,2R)-1-(5-((S)-1-(((9H-芴-9-yl)methoxy)carbonyl)amino)-4-oxo-4-(3) Benzylamino)butyl)-1,3,4-oxadiazol-2-yl)-2-(tert-butoxy)propyl)carbamic acid tert-butyl ester (3.9 g, 4.5 mmol) dissolved in two Methyl chloride (20 mL) was added diethylamine (20 mL). After completion of the reaction, the mixture was concentrated and purified by column chromatography (ethyl acetate: petroleum ether = 4:1). A white solid (1.5 g) was obtained in a 51.7% yield.

Preparation of Step 6(2S,4R)-4-Hydroxytetrahydropyrrole-2-carboxylic Acid Methyl Ester

The preparation method is the same as the preparation method of the first step in the embodiment 12 except that (2S,3S)-3-hydroxytetrahydropyrrole-2-carboxylic acid is replaced by (2S,4R)-4-hydroxytetrahydropyrrole-2. - Formic acid.

Step 7 Preparation of (2S,4R)-4-((tert-Butyldimethylsilyl)oxy)tetrahydropyrrole-2-carboxylic acid methyl ester

The preparation method is the same as the preparation method of the first step in the embodiment 11, except that the methyl (2S,4R)-N-(tert-butoxycarbonyl)-4-hydroxy-2-pyrrolecarboxylate is replaced with (2S, 4R). Methyl 4-hydroxytetrahydropyrrole-2-carboxylate.

Preparation of methyl (2S,4R)-4-((tert-butyldimethylsilyl)oxy)-1-(chloroformyl)tetrahydropyrrole-2-carboxylate

Methyl (2S,4R)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-2-carboxylate (1 g, 3.9 mmol, 1 eq) was dissolved in dichloromethane (100 mL) Pyridine (0.4 g, 5.0 mmol, 1.3 eq) was added dropwise to a solution of methylene chloride (0.5 g, 1.7 mmol, 0.44 eq, dissolved in 15 mL of DCM). The reaction was stirred at room temperature for 18 h. The mixture was extracted with citric acid and methylene chloride. EtOAc (EtOAc m.

Step 9 (1R,4S)-2-(((S)-1-(5-((1S,2R)-2-tert-butoxy-1-(tert-butoxycarbonyl)amino)propyl)-1 , 3,4-oxadiazol-2-yl)-4-oxy-4-(tritylamino)butyl)carbamoyl)-4-((tert-butyldimethylsilyl)oxy Preparation of methyl tetrahydropyrrole-1-carboxylate

((1S,2R)-1-(5-((S)-1-Amino-4-oxo-4-(tritylamino)butyl)-1,3,4-oxadiazole- tert-Butyl 2-(ethyl)-2-(tert-butoxy)propyl)carbamate (700 mg, 1.1 mmol, 1 eq) was dissolved in dioxane (10 mL) and triethylamine (331 mg) , 3.3 mmol, 3 eq) and (2S,4R)-4-((tert-butyldimethylsilyl)oxy)-1-(chloroformyl)tetrahydropyrrole-2-carboxylic acid methyl ester (422 mg, 1.3 Methyl, 1.2 eq), warmed to reflux and stirred for 12 h. To the mixed solution, citric acid and ethyl acetate were added, and the organic phase was washed with saturated sodium bicarbonate solution, water, saturated sodium chloride solution, dried over anhydrous sodium sulfate, filtered, filtered, and purified by column chromatography. PE=3:2). A white solid (300 mg) was obtained in a yield of 29.7%.

Step 10 (1R,4S)-2-(((S)-1-(5-((1S,2R)-2-tert-butoxy-1-(tert-butoxycarbonyl)amino)propyl)-1 , 3,4-oxadiazol-2-yl)-4-oxy-4-(tritylamino)butyl)carbamoyl)-4-((tert-butyldimethylsilyl)oxy Preparation of tetrahydropyrrole-1-carboxylic acid

(1R,4S)-2-(((S)-1-(5-((1S,2R)-2-tert-butoxy-1-(tert-butoxycarbonyl)amino)propyl)-1, 3,4-oxadiazol-2-yl)-4-oxy-4-(tritylamino)butyl)carbamoyl)-4-((tert-butyldimethylsilyl)oxy Methyl tetrahydropyrrole-1-carboxylate (300 mg, 0.32 mmol, 1 eq) was dissolved in tetrahydrofuran (2 mL). A 2M solution of lithium hydroxide (4.5 mg, 0.64 mmol, 2 eq dissolved in 0.05 mL water) Stir at 70 ° C for 3 h. The extract was extracted with citric acid and dichloromethane, and the organic phase was washed with EtOAc, EtOAc (EtOAc)

Step 11 (2S,4R)-1-(((S)-4-Amino-1-(5-((1S,2R)-1-amino-2-hydroxypropyl)-1,3,4- oxox Preparation of oxazol-2-yl)-4-oxobutyl)carbamoyl)-4-hydroxytetrahydropyrrole-2-carboxylic acid

The preparation method is the same as the preparation method of the step 8 in the embodiment 11, except that (2S,4R)-2-(5-((6S,10S)-10-(tert-butoxymethyl)-13,13-di Methyl-3,8,11-trioxo-1,1,1-triphenyl-12-oxy-2,7,9-azatetradecane-6-yl)-1,3,4 - Oxadiazol-2-yl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-1-carboxylic acid tert-butyl ester was replaced by (1R,4S)-2-((( S)-1-(5-((1S,2R)-2-tert-butoxy-1-(tert-butoxycarbonyl)amino)propyl)-1,3,4-oxadiazol-2-yl) -4-Oxo-4-(tritylamino)butyl)carbamoyl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole-1-carboxylic acid can be obtained Target compound. ¹ H NMR (400 MHz, D ₂ O: δ 4.67-4.65 (d, 1H), 4.39 - 4.35 (m, 1H), 4.23-4.19 (m, 1H), 4.15 - 4.13 (t, 1H), 3.05- 3.02 (m, 2H), 2.90-2.89 (d, 2H), 2.52-2.48 (t, 2H), 2.46-2.43 (m, 1H), 2.34-2.29 (m, 1H), 2.12-2.10 (t, 1H) ), 1.35-1.33 (d, 3H). ESI-MS m/z: 401.2 [M+H] ⁺ .

Example 14 (2S,3S)-1-(((S)-4-amino-1-(5-((1S,2R)-1-amino-2-hydroxypropyl)-1,3,4- Preparation of oxadiazol-2-yl)-4-oxobutyl)carbamoyl)-3-hydroxytetrahydropyrrole-2-carboxylic acid

The preparation method is the same as the production method of Example 13, except that the 4-hydroxyproline in Step 7 is replaced with 3-hydroxyproline to prepare the target compound. ¹ H NMR (400 MHz, D ₂ O): δ 4.67-4.65 (d, 1H), 4.43-4.42 (d, 1H), 4.39-4.35 (m, 1H), 4.23-4.19 (m, 1H), 4.15 -4.13(t,1H),3.57-3.45(t,2H),3.05-3.02(m,2H),2.90-2.89(d,2H),2.46-2.43(m,1H),2.34-2.29(m, 1H), 1.35-1.33 (d, 3H). ESI-MS m/z: 401.3 [M+H] ⁺ .

Example 15 (2S,3R)-2-(3-((S)-4-Amino-1-(5-(1-amino-3-(hydroxymethyl)cyclobutyl)-1,3,4 -Oxadiazol-2-yl)-4-oxobutyl)ureido)-3-hydroxybutyric acid

The preparation method was the same as the preparation method of Example 12 except that the (2S,3S)-3-hydroxytetrahydropyrrole-2-carboxylic acid in the step 1 of Example 12 was replaced with 1-amino-3-(hydroxymethyl group). The target compound can be obtained by replacing cyclobutane-1-carboxylic acid with O-(tert-butyl)-L-serine tert-butyl ester with O-(tert-butyl)-L-threonine tert-butyl ester. _{^{1 H NMR (400MHz, D 2}} O): δ5.00-4.98 (d, 2H), 4.17-4.15 (d, 1H), 3.60-3.58 (d, 2H), 2.76-2.73 (d, 1H), 2.60 -2.44(m,6H),2.24-2.22(d,1H), 2.10-2.08(d,1H),1.10-1.08(d,3H).ESI-MS m/z:415.3[M+H]+.

Example 16 2-(3-((S)-4-Amino-1-(5-(1-aminocyclopropyl)-1,3,4-oxadiazol-2-yl)-4-oxo Preparation of butyl)ureido)-3-hydroxypropionic acid

The preparation method was the same as that of the production method of Example 12 except that (2S,3S)-3-hydroxytetrahydropyrrole-2-carboxylic acid was replaced with 1-aminocyclopropane-1-carboxylic acid to obtain the target compound. ¹ H NMR (400 MHz, D ₂ O): δ 5.11-5.08 (t, 1H), 4.19-4.17 (t, 1H), 3.89-3.83 (d, 2H), 2.56-2.52 (t, 2H), 2.44 -2.37 (m, 1H), 2.30-2.23 (m, 1H), 1.63-1.59 (t, 2H), 1.59-1.54 (t, 2H). ESI-MS m/z: 357.2 [M+H] ⁺ .

Example 17 (S)-2-(3-((S)-4-Amino-1-(5-(1-amino-3-(hydroxy)cyclobutyl)-1,3,4-oxadiazole) Preparation of -2-yl)-4-oxobutyl)ureido)-3-hydroxypropionic acid

The preparation method was the same as the preparation method of Example 12 except that (2S,3S)-3-hydroxytetrahydropyrrole-2-carboxylic acid was replaced by 1-amino-3-(hydroxymethyl)cyclobutane-1- Formic acid can be used to prepare the target compound. _{^{1 H NMR (400MHz, D 2}} O): δ4.17-4.15 (d, 2H), 3.89-3.83 (d, 2H), 3.60-3.58 (d, 2H), 2.76-2.73 (d, 1H), 2.60 - 2.44 (m, 6H), 2.24 - 2.22 (m, 1H), 2.10 - 2.08 (m, 1H). ESI-MS m/z: 415.3 [M+H] ⁺ .

Example 18 1-(3-((S)-4-Amino-1-(5-((1S,2R)-1-amino-2-hydroxypropyl)-1,3,4-oxadiazole- Preparation of methyl 2-yl)-4-oxobutyl)ureido)cyclopropylcarboxylate

The preparation methods of steps 1 to 5 are the same as the preparation methods of steps 1 to 5 in Example 13, and the preparation methods of steps 6 to 8 are the same as the preparation methods of steps 6 to 8 in Example 11, except that O-(tert-butyl group) is used. The L-serine tert-butyl ester is replaced with methyl 1-aminocyclopropane-1-carboxylate to obtain the target compound. ¹ H NMR (400 MHz, D ₂ O): δ 5.01-4.98 (m, 1H), 4.61-4.59 (d, 1H), 4.28-4.25 (t, 1H), 3.59 (s, 3H), 2.40-2. (t, 2H), 2.30-2.27 (m, 1H), 2.25-2.23 (m, 1H), 1.47 (t, 2H), 1.24-1.23 (d, 3H), 1.13 (t, 2H). ESI-MS m/z: 385.2 [M+H] ⁺ .

Example 19 (((S)-4-Amino-1-(5-(1-amino-3-hydroxycyclobutyl)-1,3,4-oxadiazol-2-yl)-4-oxo Preparation of butyl)carbamoyl)-L-serine

The preparation method is the same as the preparation method of Example 12, except that (2S,3S)-3-hydroxytetrahydropyrrole-2-carboxylic acid is replaced by 1-amino-3-hydroxycyclobutane-1-carboxylic acid. The target compound is obtained. ¹ H NMR (400 MHz, D ₂ O): δ 5.11-5.08 (t, 1H), 4.59-4.52 (m, 1H), 4.28-4.25 (t, 1H), 3.89-3.83 (d, 2H), 2.63 - 2.60 (d, 2H), 2.40-2.37 (t, 2H), 2.37-2.34 (d, 2H), 2.30-2.27 (m, 1H), 2.25-2.23 (m, 1H). ESI-MS m/z :387.2[M+H] ⁺ .

Example 20 (S)-4-(5-(1-Amino-3-(hydroxymethyl)cyclobutyl)-1,3,4-oxadiazol-2-yl)-4-(3-( Preparation of (1S,2R)-1-carboxy-2-hydroxypropyl)ureido)butyric acid

The preparation method is the same as the preparation method of Example 15, except that N ² -(((9H-fluoren-9-yl)methoxy)carbonyl)-N ⁵ -trityl-L-glutamine is replaced with (S)-2-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)-5-(tert-butoxy)-5-oxopentanoic acid can be obtained to obtain the target compound. _{^{1 H NMR (400MHz, D 2}} O): δ5.00-4.98 (d, 2H), 4.17-4.15 (d, 1H), 3.60-3.58 (d, 2H), 2.76-2.73 (d, 1H), 2.60 - 2.44 (m, 6H), 2.24 - 2.22 (d, 1H), 2.10 - 2.08 (d, 1H), 1.10-1.08 (d, 3H). ESI-MS m/z: 416.2 [M+H] ⁺ .

Example 21 (S)-4-(5-(1-Amino-3-(hydroxymethyl)cyclobutyl)-1,3,4-oxadiazol-2-yl)-4-(3-( Preparation of (S)-1-carboxy-2-hydroxyethyl)ureido)butyric acid

The preparation method is the same as the preparation method of Example 17, except that N ² -(((9H-fluoren-9-yl)methoxy)carbonyl)-N ⁵ -trityl-L-glutamine is replaced with (S)-2-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)-5-(tert-butoxy)-5-oxopentanoic acid can be obtained to obtain the target compound. _{^{1 H NMR (400MHz, D 2}} O): δ4.17-4.15 (d, 2H), 3.89-3.83 (d, 2H), 3.60-3.58 (d, 2H), 2.76-2.73 (d, 1H), 2.60 - 2.44 (m, 6H), 2.24 - 2.22 (m, 1H), 2.10 - 2.08 (m, 1H). ESI-MS m/z: 402.2 [M+H] ⁺ .

Example 22 ((1-(5-((1S,2R)-1-Amino-2-hydroxypropyl)-1,3,4-oxadiazol-2-yl)cyclopropyl)carbamoyl)- L-serine preparation

The preparation method of the steps 1 to 5 is the same as the preparation method of the steps 1 to 5 in the embodiment 13, except that N ² -(((9H-fluoren-9-yl)methoxy)carbonyl)-N ⁵ -3 Benzyl-L-glutamine is replaced by 1-(((9H-芴-9-yl)methoxy)carbonyl))amino)cyclopropane-1-carboxylic acid, and the preparation methods of steps 6-8 are the same In the preparation method of 6 to 8 in Example 11, the target compound can be obtained. _{^{1 H NMR (400MHz, D 2}} O): δ5.11-5.08 (t, 1H), 5.01-4.98 (m, 1H), 4.61-4.59 (d, 1H), 3.89-3.83 (d, 2H), 1.47 (t, 2H), 1.24-1.23 (d, 3H), 1.13 (t, 2H). ESI-MS m/z: 330.2 [M+H] ⁺ .

Example 23 (2S,3S)-2-(3-((S)-4-Amino-1-(5-(4-aminotetrahydro-2H-pyran-4-yl)-1,3,4 -Oxadiazol-2-yl)-4-oxobutyl)ureido)-3-hydroxybutyric acid

Step 1 Preparation of 4-aminotetrahydro-2H-pyran-4-carboxylic acid methyl ester

4-Aminotetrahydro-2H-pyran-4-carboxylic acid (5.00 g, 34.48 mmol) was dissolved in 50 mL of methanol, stirred and cooled to -10 ° C, and thionyl chloride (13.96 g, 103.38 mmol) was slowly added dropwise. The temperature was refluxed for 3 hours. The reaction solution was concentrated to remove methanol and dichloromethane, and 6.5 g of crude product was obtained.

Step 2 Preparation of methyl 4-(tert-butoxycarbonyl)aminotetrahydro-2H-pyran-4-carboxylate

Methyl 4-aminotetrahydro-2H-pyran-4-carboxylate (6.50 g, 0.04 mol) was dissolved in 65 mL of tetrahydrofuran and 65 mL of water, sodium bicarbonate (12.10 g, 0.14 mol) was added, and the mixture was stirred and cooled to 0 ° C. Di-tert-butyl dicarbonate (8.50 g, 0.038 mol) was added, and the reaction was allowed to warm up to room temperature for about 24 h. The reaction mixture was concentrated with EtOAc (EtOAc)EtOAc.

Step 3 Preparation of 4-(tert-butoxycarbonyl)aminotetrahydro-2H-pyran-4-hydrazide

Methyl 4-(tert-butoxycarbonyl)aminotetrahydro-2H-pyran-4-carboxylate (5.30 g, 0.02 mmol) was dissolved in 53 mL of methanol, then hydrazine hydrate (13 mL, 0.2 mmol). The reaction mixture was concentrated, and the residue was crystallised from methylene chloride.

Step 4 (4-(2-(N ² -((9H-indol-9-yl)methoxy)carbonyl)-N ⁵ -trityl-L-glutamyl)indole-1-carbonyl) Preparation of tert-butyl tetrahydro-2H-pyran-4-yl)carbamate

4-(tert-Butoxycarbonyl)aminotetrahydro-2H-pyran-4-hydrazide (1.40 g, 5.40 mmol) was dissolved in 14 mL of DMF and N ² -((((9H-芴-9) - yl) methoxy) carbonyl) -N ⁵ - trityl-glutamine -L- (3.30g, 5.40mmol), until complete dissolution, was added NMM (1.36g, 13.50mmol) and HATU (2.05g , 5.40 mmol), adding room temperature reaction for 3 h, the reaction liquid was added to 60 mL of ice water, and the solid was precipitated, suction filtered, washed with water, and dried to give a product 4.5 g, yield 97.8%.

Step 5 (S)-(4-(5-(1-(((9H-芴-9-yl))methoxy)carbonyl)amino)-4-carbonyl-4-(trimethylamino)butane Of tert-butyl-1,3,4-oxadiazol-2-yl)tetrahydro-2H-pyran-4-yl)carbamate

(4-(2-(N ² -((9-Dithio)methoxy)carbonyl)-N ⁵ -trityl-L-glutamyl)indole-1-carbonyl)-tetrahydro -2H pyran-4)-tert-butyl carbamate (4.00 g, 4.59 mmol) was dissolved in 40 mL of dichloromethane, and triphenylphosphine TPP (3.40 g, 9.18 mmol) was added at room temperature. The temperature was lowered to -10 ° C, and iodine (2.32 g, 9.18 mmol) was slowly added to the reaction mixture. After the iodine was completely dissolved, triethylamine (3.72 g, 36.72 mmol) was added, and the mixture was added to room temperature for 2 h. After the reaction was completed, the reaction was concentrated and evaporated with ethyl acetate. EtOAcjjjjjjjjjjjjjj .

Step 6 (S)-(4-(5-(1-Amino-4-carbonyl-4-tritylamino)butyl)-1,3,4-oxadiazol-2-yl)tetrahydro- Preparation of tert-butyl 2H-pyran-4-yl)carbamate

(S)-(4-(5-(1-(((9H-芴-9-yl))methoxy)carbonyl)amino)-4-carbonyl-4-(trimethylamino)butyl -1,3,4-oxadiazol-2-yl)tetrahydro-2H-pyran-4-yl)carbamic acid tert-butyl ester (2.0 g, 2.11 mmol), dissolved in dichloromethane (20 mL) 20 mL of ethylenediamine was added to the reaction at room temperature for 6 h, and the reaction was completed by TLC. The reaction mixture was concentrated and purified by column chromatography.

Step 7 N-(((S)-1-(5-(4-(di-tert-Butyl)-)-tetrahydro-2H-pyran-4-yl)-1,3,4-Ethyl Preparation of oxazol-2-yl)-4-carbonyl-4-(tritylamino)butyl)carbamoyl)-O-(tert-butyl)-L-threonine tert-butyl ester

(S)-(4-(5-(1-Amino-4-carbonyl-4-tritylamino)butyl)-1,3,4-oxadiazol-2-yl)tetrahydro-2H tert-Butyl pyran-4-yl)carbamate (300 mg, 0.49 mmol), dissolved in 3 mL of DMF, added triethylamine (100 mg, 0.98 mmol), and then cooled to 0 ° C. tert-Butyl)-N-((4-nitrophenyl)carbamoyl)-L-isoleucine tert-butyl ester (387 mg, 0.53 mmol), added to room temperature for 10 h, poured into the reaction solution The mixture was extracted with EtOAc (EtOAc)EtOAc.

Step 8 (2S,3S)-2-(3-((S)-4-Amino-1-(5-(4-aminotetrahydro-2H-pyran-4-yl)-1,3,4- Preparation of oxadiazol-2-yl)-4-oxobutyl)ureido)-3-hydroxybutyric acid

N-(((S)-1-(5-(4-((di-tert-Butyl)))-tetrahydro-2H-pyran-4-yl)-1,3,4-oxan Zyridin-2-yl)-4-carbonyl-4-(tritylamino)butyl)carbamoyl)-O-(tert-butyl)-L-threonine tert-butyl ester (300 mg, 0.345 mmol) Dissolve in 5 mL of dichloromethane, add 5 mL of trifluoroacetic acid at room temperature, add two drops of triisopropylethylamine dropwise, and react at room temperature for 5 h. The reaction solution was concentrated, and 15 mL of water was added to the residue, and the mixture was extracted with methylene chloride. The aqueous layer was lyophilized and passed through a reverse phase column to give product. ¹ H NMR (400 MHz, D ₂ O) δ 4.97 (dd, J = 9.5, 4.9 Hz, 1H), 4.25 (dd, J = 12.2, 9.7 Hz, 1H), 4.18 (d, J = 13.8 Hz, 1H) ), 3.93 (d, J = 12.0 Hz, 2H), 3.49 (td, J = 11.6, 5.9 Hz, 2H), 2.56 - 2.02 (m, 8H), 1.09 (d, J = 6.3 Hz, 3H). ESI - MS m/z: 511.2 [M+H] ⁺ _.

Example 24 (S)-2-(3-((S)-4-Amino-1-(5-(4-aminotetrahydro-2H-pyran-4-yl)-1,3,4-oxa) Preparation of oxazol-2-yl)-4-oxobutyl)ureido)-3-hydroxypropionic acid

By the synthesis route of Example 23, (((S)-4-amino-1-(5-(4-amino-2H-pyran-4-yl)-1,3,4-oxadiazole) can be synthesized. -2-yl)-4-butylcarbonyl)carboxamide)-L-serine. ¹ H NMR (400 MHz, D ₂ O) δ 4.96 (dd, J = 9.7, 4.9 Hz, 1H), 4.24 (t, J = 4.2 Hz, 1H), 3.92 (d, J = 12.3 Hz, 2H), 3.83 (dd, J = 11.7, 4.8 Hz, 1H), 3.73 (dd, J = 11.6, 3.8 Hz, 1H), 3.48 (td, J = 11.1, 5.8 Hz, 2H), 2.49 - 2.34 (m, 4H) , 2.26 (dt, J = 13.0, 7.0 Hz, 1H), 2.18 - 2.04 (m, 3H). ESI-MS m/z: 401.2 [M+H] ⁺ .

Example 25 (S)-4-(5-(4-Aminotetrahydro-2H-pyran-4-yl)-1,3,4-oxadiazol-2-yl)-4-(3-( Preparation of (1S,2S)-1-carboxy-2-hydroxypropyl)ureido)butyric acid

By the synthesis route of Example 23, (S)-4-(5-(4-aminotetrahydro-2H-pyran-4-yl)-1,3,4-oxadiazol-2-yl can be synthesized. -4-(3-((1S,2S)-1-carboxy-2-hydroxypropyl)ureido)butyric acid. ¹ H NMR (400 MHz, D ₂ O) δ 4.94 (d, J = 7.0 Hz, 1H), 4.19 (d, J = 5.7 Hz, 1H), 4.07 (s, 1H), 3.88 (d, J = 12.5) Hz, 2H), 3.44 (t, J = 12.0 Hz, 2H), 2.41 (dd, J = 19.7, 10.2 Hz, 3H), 2.29 - 2.15 (m, 1H), 2.08 (t, J = 10.8 Hz, 3H) ), 1.03 (d, J = 6.2 Hz, 3H). ESI-MS m/z: 416.2 [M+H] ⁺ .

Example 26 (S)-4-(5-(4-Aminotetrahydro-2H-pyran-4-yl)-1,3,4-oxadiazol-2-yl)-4-(3-( Preparation of (S)-1-carboxy-2-hydroxyethyl)ureido)butyric acid

By the synthesis route of Example 23, (S)-4-(5-(4-aminotetrahydro-2H-pyran-4-yl)-1,3,4-oxadiazol-2-yl can be synthesized. -4-(3-((1S,2S)-1-carboxy-2-hydroxyethyl)ureido)butyric acid. ¹ H NMR (400 MHz, D ₂ O) δ 5.03 - 4.93 (m, 1H), 4.21. (d, J = 4.0 Hz, 1H), 3.91 (s, 2H), 3.79 (dd, J = 11.4, 4.7 Hz , 1H), 3.76–3.66 (m, 1H), 3.46 (d, J=9.3 Hz, 2H), 2.53–2.33 (m, 4H), 2.23 (d, J=5.1 Hz, 1H), 2.10 (s, 3H). ESI-MS m/z: 402.2 [M+H] ⁺ .

Example 27 (S)-4-(3-(4-Aminotetrahydro-2H-pyran-4-yl)-1,2,4-oxadiazol-5-yl)-4-(3-( Preparation of (S)-1-carboxy-2-hydroxyethyl)ureido)butyric acid

Step 1 Preparation of 4-aminotetrahydro-2H-pyran-4-carboxylic acid methyl ester

4-Aminotetrahydro-2H-pyran-4-carboxylic acid (5.00 g, 34.48 mmol) was dissolved in 50 mL MeOH, stirred and cooled to -10 ° C, and thionyl chloride (13.96 g, 103.38 mmolq) was slowly added dropwise. The temperature was refluxed for 3 h. The reaction solution was concentrated to remove methanol and dichloromethane, and 6.5 g of crude product was obtained.

Step 2 Preparation of methyl 4-(tert-butoxycarbonyl)aminotetrahydro-2H-pyran-4-carboxylate

Methyl 4-aminotetrahydro-2H-pyran-4-carboxylate (6.50 g, 0.04 mol) was dissolved in 65 mL of tetrahydrofuran and 65 mL of water, sodium bicarbonate (12.10 g, 0.14 mol) was added, and the mixture was stirred and cooled to 0 ° C. Add di-tert-butyl dicarbonate (8.50 g, 0.038 mol) and add to room temperature for about 24 h. The reaction mixture was concentrated with EtOAc (EtOAc)EtOAc.

Step 3 Preparation of 4-(tert-butoxycarbonyl)aminotetrahydro-2H-pyran-4-carboxylic acid

Methyl 4-(tert-butoxycarbonyl)aminotetrahydro-2H-pyran-4-carboxylate (7.00 g, 27.02 mmol) was dissolved in 70 mL of methanol, then 40 mL water was added, then (1.63 g, 40. After reacting for 4 h, the reaction mixture was adjusted to pH 4-5 with 1N hydrochloric acid, and then extracted with ethyl acetate, washed with water and dried to give a white solid, 5.0 g, yield 75.7%.

Step 4 Preparation of 4-(tert-Butoxycarbonyl)aminotetrahydro-2H-pyran-4-carboxamide

4-(tert-Butoxycarbonyl)aminotetrahydro-2H-pyran-4-carboxylic acid (5.00 g, 20 mmol) was dissolved in 50 mL of THF. NMM (2.50 g, 24 mmol) was added at room temperature and the reaction was cooled to - Ethyl chloroformate (2.70 g, 24 mmol) was slowly added dropwise at 10 ° C, and the reaction was carried out at low temperature for 2 h. Ammonia water (13 mL, 160 mmol) was slowly added dropwise at low temperature. After adding low temperature reaction for 3 h, the reaction was complete and the reaction solution was concentrated. The extract was extracted with EtOAc. EtOAc (EtOAc)EtOAc.

Step 5 Preparation of (4-cyanotetrahydro-2H-pyran-4-yl)carbamic acid tert-butyl ester

4-(tert-Butoxycarbonyl)aminotetrahydro-2H-pyran-4-carboxamide (3.70 g, 15.14 mmol) was dissolved in pyridine (12.0 g, 151.4 mmol), and trifluoroacetic anhydride was added dropwise at low temperature ( 4.80g, 22.71mmol) After the addition of room temperature for 4h, the reaction mixture was poured into a saturated aqueous solution of sodium bicarbonate, and extracted with ethyl acetate. The organic layer was washed with 1M EtOAc. The crude product was concentrated and washed with petroleum ether to give 2.9 g of product.

Step 6 Preparation of E-(4-(N'-hydroxymethylindenyl)tetrahydro-2H-pyran-4-yl)carbamic acid tert-butyl ester

(4-Cyanotetrahydro-2H-pyran-4-yl)carbamic acid tert-butyl ester (2.50 g, 0.01 mol), dissolved in 25 mL of ethanol, and then added 5 mL of water, hydroxylamine hydrochloride (1.20 g, 0.015 mol) ), potassium carbonate (2.30 g, 0.015 mol), and the temperature rise reflux reaction was added. The reaction mixture was concentrated, and the residue was evaporated, evaporated, evaporated, evaporated

Step 7 Tert-Butyl (S,Z)-4-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)-5-((((((((((((((((((( Preparation of ethyl tetrahydro-2H-pyran-4-yl)methylene)amino)oxy)-5-oxopentanoate

E-(4-(N'-hydroxymethylindenyl)tetrahydro-2H-pyran-4-yl)carbamic acid tert-butyl ester (2.00 g, 7.72 mmol) was dissolved in 20 mL DCM, then NMM ( 1.6 g, 15.44 mmol), (S)-2-((((9H-indol-9-yl)methoxy)carbonyl)amino)-5-(tert-butoxy)-5-oxopentanoic acid (3.6 g, 8.49 mmol) was added to room temperature, and the reaction was completed by TLC. The reaction mixture was concentrated, and the residue was subjected to column chromatography.

Step 8 Tert-Butyl (S)-4-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)-4-(3-(4-((tert-butoxycarbonyl)amino) Preparation of ethyl tetrahydro-2H-pyrano-pyridin-4-yl)-1,2,4-oxadiazol-5-yl)butanoate

tert-Butyl (S,Z)-4-((((9H-芴-9-yl)methoxy)carbonyl)amino)-5-(((((((((((((((((((((((((((((((( Tetrahydro-2H-pyran-4-yl)methylene)amino)oxy)-5-oxopentanoate (2.20 g, 3.29 mmol) was dissolved in 22 mL of ethanol and 3 mL of water, then sodium acetate was added. The mixture was heated to reflux, and the mixture was evaporated to dryness. The residue was evaporated.

Step 9 tert-Butyl (S)-4-amino-4-(3-(4-((tert-butoxycarbonyl)amino)tetrahydro-2H-pyran-4-yl)-1,2,4- Preparation of Oxadiazole-5-yl) Butyrate

tert-Butyl (S)-4-(((9H-fluoren-9-yl)methoxy)carbonyl)amino)-4-(3-(4-((tert-butoxycarbonyl))amino) Hydrogen-2H-pyrano-pyridin-4-yl)-1,2,4-oxadiazol-5-yl)butyric acid ethyl ester (1.80 g, 2.77 mmol), dissolved in 18 mL dichloromethane, then 18 mL Diethylamine was added to room temperature for 6 h, and TLC was monitored until the reaction was completed. The reaction solution was concentrated and subjected to column chromatography to give a white solid.

Step 10 tert-Butyl (S)-4-(3-(4-((tert-butoxycarbonyl)amino)tetrahydro-2H-pyran-4-yl)-1,2,4-oxadiazole- Preparation of 5-ethyl)-4-(3-((S)-1,3-di-tert-butoxy-1-oxopropan-2-yl)ureido)butyric acid ethyl ester

tert-Butyl (S)-4-amino-4-(3-(4-((tert-butoxycarbonyl)amino)tetrahydro-2H-pyran-4-yl)-1,2,4-oxo Diazol-5-yl)butyrate (300 mg, 0.70 mmol), dissolved in 3 mL of DMF, added triethylamine (142 mg, 1.40 mmol), cooled to 0 ° C, then added O- (tert-butyl) -N-((4-Nitrophenyl)carbamoyl)-L-serine tert-butyl ester (352mg, 0.77mmol), added to room temperature for 10h, the reaction solution was poured into 20mL of water, with acetic acid The organic layer was washed with 1 M citric acid and washed with saturated sodium hydrogen sulfate.

Step 11 (S)-4-(3-(4-Aminotetrahydro-2H-pyran-4-yl)-1,2,4-oxadiazol-5-yl)-4-(3-(( S)-1-carboxy-2-hydroxyethyl)ureido)butyric acid

tert-Butyl (S)-4-(3-(4-((tert-butoxycarbonyl)amino)tetrahydro-2H-pyran-4-yl)-1,2,4-oxadiazole-5 Ethyl 4-(3-((S)-1,3-di-tert-butoxy-1-oxopropan-2-yl)ureido)butyrate (150 mg, 0.219 mmol) was dissolved in 5 mL In dichloromethane, 5 mL of trifluoroacetic acid was added at room temperature, and two drops of triisopropylethylamine were added dropwise, and the reaction was concentrated at room temperature for 5 h. The reaction mixture was concentrated, and 15 mL of water was added to the residue, and extracted with dichloromethane. Dry to give the product. ¹ H NMR (400 MHz, D ₂ O) δ 4.94 (dt, J = 17.8, 8.9 Hz, 1H), 4.16 (t, J = 3.5 Hz, 1H), 3.86 - 3.71 (m, 3H), 3.65 (dd , J = 11.6, 3.5 Hz, 1H), 3.46 (t, J = 11.4 Hz, 2H), 2.40 (t, J = 6.9 Hz, 2H), 2.31 (d, J = 13.6 Hz, 2H), 2.18 (td , J = 13.3, 6.6 Hz, 1H), 2.11 - 1.92 (m, 3H). ESI-MS m/z: 402.2 [M+H] ⁺ _.

Example 28 (S)-3-Amino-3-(3-((2S,4R)-4-hydroxytetrahydropyrrole-2-yl)-1,2,4-oxadiazol-5-yl)propane Preparation of amide

Step 1: Preparation of (2S,4R)-1-tert-butoxycarbonyl-2-cyano-4-(tert-butyldimethylsilyl)oxytetrahydropyrrole

Compound 1a (30 g, 141.34 mmol) was dissolved in DMF (300 mL), EtOAc (11.55 g, 169.61 mmol) was added, and then cooled to -5 ° C, then a solution of TBDMSCl (25.56 g, 169.61 mmol) in DMF (120 mL) was slowly added dropwise. The reaction was stirred for 2 h, and the mixture was stirred at room temperature for 13 h. The reaction mixture was poured into a saturated aqueous solution of ammonium chloride and then evaporated. Distillation under reduced pressure gave a yellow oily solid, which was crystallised to white solid. The crude compound was purified by silica gel column chromatography (eluent: 0-5% ethyl acetate in petroleum ether). The mixture was cooled to 44.61 g of a white solid compound 1b (yield: 91.7%).

Step 2: (2S,4R)-1-tert-Butoxycarbonyl-2-((Z)-N'-hydroxymethylindenyl)-4-(tert-butyldimethylsilyl)oxytetrahydropyrrole preparation

Compound 1b (20 g, 61.25 mmol) was dissolved in ethanol (200 mL), and then potassium carbonate (12.70 g, 91.88 mmol) and hydroxylamine hydrochloride (6.38 g, 91.88 mmol) were added, and the mixture was refluxed for 5 h. The reaction was filtered, the filtrate by rotary evaporation, ethyl acetate and aqueous cleaning liquid separation, and saturated brine, the organic phase was washed several times with water, dried over anhydrous Na ₂ SO _4, evaporated under reduced pressure, ethyl acetate was added to the obtained solid Ester, ultrasonic, filtration, filter cake is dissolved in a small amount of tetrahydrofuran, a large amount of petroleum ether is added to crystallize, filtered, and the filter cake is pure white solid. The filtrate is distilled under reduced pressure and purified by silica gel column chromatography (eluent: petroleum ether 0- 30% ethyl acetate). The obtained solid was combined with a filter cake to give 9.6 g of product (yield: 43.6%).

Step 3: (2S,4R)-1-tert-Butoxycarbonyl-2-(5-((S)-1-(((9H-fluoren-9-yl))methoxy)carbonyl)amino)-3 -keto-3-(tritylamino)propyl)-1,2,4-oxadiazol-3-yl)-4-((tert-butyldimethylsilyl)oxy)tetrahydrol Preparation of pyrrole

The compound Fmoc-Asn(Trt)-OH (20.71 g, 34.71 mmol) was dissolved in dichloromethane (200 mL), cooled in an ice bath, and BAST (8.45 g, 38.18 mmol) was added at -7 ° C. . The reaction solution was evaporated under reduced pressure, and the mixture was evaporated, evaporated, filtered, and then filtered, and then filtered, and then filtered and dried with tetrahydrofuran (200 mL). Compound 1c (9.6 g, 26.70 mmol), nitrogen methyl morpholine (5.40) g, 53.40 mmol), the reaction was stirred at room temperature for 13 h. Tetrahydrofuran was distilled off under reduced pressure, and ethanol (200 mL) and sodium acetate (3.29 g, 40.05 mmol) were directly added thereto, and the mixture was stirred and refluxed for 2.5 hours. The reaction mixture was evaporated under reduced pressure. EtOAc was evaporated, evaporated, evaporated, evaporated, evaporated. Agent: 0-25% ethyl acetate in petroleum ether) gave 7.18 g of pale yellow solid 1d (yield: 29.2%).

Step 4: (2S,4R)-1-tert-Butoxycarbonyl-2-(5-((S)-1-amino-3-keto-3-(tritylamino)propyl)-1, Preparation of 2,4-oxadiazol-3-yl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole

Compound 1d (6.0 g, 6.52 mmol) was added to dichloromethane (60 mL), and diethylamine (30 mL) was added dropwise, and the mixture was stirred at room temperature for about 1.5 h, and the solvent was evaporated under reduced pressure. Agent: 0-45% ethyl acetate in petroleum ether) 2.8 g of product 1e (yield: 61.5%) as a yellow oil.

Step 5: (S)-3-Amino-3-(3-((2S,4R)-4-hydroxytetrahydropyrrol-2-yl)-1,2,4-oxadiazol-5-yl)-propyl Preparation of amide

Compound 1e (600 mg, 0.86 mmol) was dissolved in dichloromethane (18 mL), trifluoroacetic acid (18 mL) and a catalytic amount of triisopropylsilane were added at room temperature, and the mixture was stirred at room temperature for 4.5 hr. The liquid phase was purified to give Compound 1. _{^{1 H NMR (300MHz, D 2}} O) δ5.05 (dd, J = 10.1,7.3Hz, 1H), 4.72 (s, 1H), 4.62 (d, J = 6.4Hz, 1H), 3.51 (dd, J =12.6, 4.2 Hz, 1H), 3.33 (d, J = 12.7 Hz, 1H), 2.99 - 2.84 (m, 2H), 2.54 - 2.31 (m, 2H). ESI-MS m/z: 242.0 [M+ H] ⁺ .

Example 29 (2S,3R)-2-(3-((S)-3-Amino-1-(3-((2S,4R)-4-hydroxytetrahydropyrrol-2-yl)-1,2 Of 4-oxaoxazol-5-yl)-3-oxopropyl)ureido)-3-hydroxybutyric acid

Step 1: (2S,4R)-1-tert-Butoxycarbonyl-2-(5-((5S,9S)-9-((R)-1-(tert-butyl)ethyl)-12,12- Dimethyl-3,7,10-trione-1,1,1-triphenyl-11-oxa-2,6,8-triaza-5-yl)-1,2,4- Preparation of Oxadiazol-3-yl)-4-((tert-butyldimethylsilyl)oxy)tetrahydropyrrole

Compound 1e (1.0 g, 1..43 mmol) was dissolved in tetrahydrofuran (10 mL). Compound 2b (0.68 g, 1.72 mmol) and triethylamine (0.29 g, 2.86 mmol). After stirring at room temperature for 24 hours, the solvent was evaporated under reduced pressure, and ethyl acetate and water were evaporated and evaporated. The organic phase was washed several times with saturated brine, dried over anhydrous sodium sulfate and evaporated. : 0-25% ethyl acetate in petroleum ether to give 700 mg of pale yellow crystal 2a (yield: 51.3%).

Step 2: (2S,3R)-2-(3-((S)-3-Amino-1-(3-((2S,4R)-4-hydroxytetrahydropyrrole-2-yl)-1,2 Of 4-oxaoxazol-5-yl)-3-oxopropyl)ureido)-3-hydroxybutyric acid

Compound 2a (550 mg, 0.576 mmol) was dissolved in dichloromethane (11.5 mL), trifluoroacetic acid (11.5 mL) was added at room temperature, and a catalytic amount of triisopropylsilane was stirred at room temperature for 5 h, and the reaction solvent was evaporated under reduced pressure. Dichloromethane and water were dissolved and separated, and the organic phase was extracted several times with water, and the aqueous phase was combined, washed several times with dichloromethane, lyophilized, and purified in liquid phase to obtain compound 2. ¹ H NMR (500 MHz, D ₂ O) δ 5.46 (t, J = 6.4 Hz, 1H), 5.25 - 5.19 (m, 1H), 4.85 (s, 1H), 4.26 (dt, J = 17.5, 8.7 Hz) , 1H), 4.02 (d, J = 17.0 Hz, 1H), 3.67 (dt, J = 13.3, 6.7 Hz, 1H), 3.55 - 3.47 (m, 1H), 3.20 - 3.11 (m, 2H), 2.62 ( Dd, J = 14.1, 7.1 Hz, 1H), 2.50 (tt, J = 9.4, 4.7 Hz, 1H), 1.22 (d, J = 6.4 Hz, 3H). ESI-MS m/z: 386.9 [M+H ] ⁺ .

Step 3: Preparation of O-(tert-butyl)-N-((4-nitrophenoxy)carbonyl)-L-threonine tert-butyl ester

H-Thr(O ^t Bu)-O ^t Bu (15 g, 64.84 mmol) was dissolved in dichloromethane (150 mL), cooled in ice-cooling, and triethylamine (9.84 g, 97.26 mmol) was added dropwise at -5 °C. And a solution of 4-chlorophenyl chloroformate (14.38 g, 71.33 mmol) in dichloromethane (60 mL), EtOAc (EtOAc) Filtration, the filtrate was evaporated under reduced pressure to remove a portion of solvent, and a mixture of ethyl acetate and petroleum ether in 1:1 was added, and solids were separated and filtered. The filtrate was evaporated under reduced pressure and purified by silica gel column chromatography (eluent: petroleum ether) 0-5% ethyl acetate) gave 13.86 g of a yellow oily liquid 2b (yield: 53.9%).

Example 30 (S)-2-(3-((S)-3-Amino-1-(3-((2S,4R)-4-hydroxytetrahydropyrrole-2-yl)-1,2,4 -Oxadiazole-5-yl)-3-oxopropyl)ureido)-3-hydroxypropionic acid

The title compound was synthesized in a similar manner to the preparation of Example 29, in which H-Thr(OtBu)-OtBu in Example 29 was replaced with H-Ser(O ^t Bu)-O ^t Bu. ¹ H NMR (300 MHz, D ₂ O) δ 5.36 (t, J = 6.1 Hz, 1H), 5.19 - 5.09 (m, 1H), 4.75 (s, 1H), 4.06 (d, J = 4.3 Hz, 1H) ), 3.75 (d, J = 6.1 Hz, 2H), 3.59 (dd, J = 12.6, 3.9 Hz, 1H), 3.41 (d, J = 12.8 Hz, 1H), 3.03 (t, J = 6.6 Hz, 2H) ), 2.58 - 2.35 (m, 2H). ESI-MS m/z: 372.9 [M+H] ⁺ .

Example 31 (S)-3-(3-((R)-1-Amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3-(3-(( Preparation of S)-2-ketotetrahydrofuran-3-yl)ureido)propanamide

Step 1: Preparation of (S)-2-(tert-butoxycarbonyl)amino-3-tert-butoxy-1-propanamide

L-Boc-Ser(tBu)-OH (50g, 191.45mmol) was dissolved in tetrahydrofuran (500mL), N-methylmorpholine (23.2g, 229.74mmol) was added, and the temperature was lowered to -15 ° C, then the chloroformic acid was slowly added dropwise. Ethyl ester (24.8 g, 229.74 mmol), stirred at -15 ° C for 1.5 h; slowly added ammonia water (48 mL, 693.48 mmol) to the reaction solution, and the mixture was heated to -5 ° C for 2.5 h, and the tetrahydrofuran was distilled off under reduced pressure. Ethyl acetate and water were lysed and separated, and the organic phase was washed with 1M citric acid, saturated sodium hydrogen carbonate and brine, dried over anhydrous sodium sulfate and evaporated. Recrystallization gave 39.3 g of a white solid 4a (yield: 78.9%).

Step 2: Preparation of (R)-(2-(tert-butoxy)-1-cyanoethyl)carbamic acid tert-butyl ester

The compound 4a (39 g, 149.81 mmol) was dissolved in pyridine (118.5 g, 1498.1 mmol), and the mixture was cooled in an ice bath, and trifluoroacetic anhydride (47.2 g, 224.72 mmol) was added dropwise at -5 ° C for 40 min, and the ice bath was removed. The reaction mixture was stirred at room temperature for 3.5 hr, and the mixture was evaporated, evaporated, evaporated, evaporated Yield: 102.9%).

Step 3: Preparation of (R,Z)-(1-amino-3-(tert-butoxy)-1-(indolyl)propan-2-yl)carbamic acid tert-butyl ester

The compound 4b (23 g, 184.88 mmol) was dissolved in ethanol (450 mL), and then potassium carbonate (38.34 g, 277.33 mmol), hydroxylamine hydrochloride (19.28 g, 277.33 mmol) was added, stirred, refluxed for 1.5 h, and evaporated under reduced pressure. Solvent, add ethyl acetate and water to dissolve, liquid separation, the organic phase is washed several times with saturated brine, dried over anhydrous sodium sulfate, and evaporated under reduced pressure to give a yellow oily liquid, which is cooled and then condensed to a pale yellow solid. It was beaten, filtered, and the filter cake was dried to give 38.67 g of white solid 4c (yield: 76.0%).

Step 4: tert-Butyl-((5S,Z)-9-amino-13,13-dimethyl-3,6-dione-1,1,1-triphenyl-7,12-dioxo Preparation of (hetero-2,8-aza-8-ene-5,10-diyl)dicarbamic acid (9H-fluoren-9-yl)methyl ester

Fmoc-Asn(Trt)-OH (10 g, 36.32 mmol) and compound 4c were dissolved in DMF (200 mL), cooled in an ice-bath, and then, at -5 °C, HOBt (5.90 g, 43.58 mmol), and EDC (8.35 g, 43.58mmol), stirring in an ice bath for 20min, heating, room temperature reaction for 4h, the reaction liquid was poured into water, a large amount of solids were precipitated, filtered, and the filter cake was washed several times with water, and dried to obtain 33.8 g of white solid 4d (yield: 108.98%) ).

Step 5: ((R)-1-(5-((S)-1-(((9H-芴-9-yl)methoxy)carbonyl)))))))) Preparation of tert-butyl ester of benzylamino)propyl)-1,2,4-oxadiazol-3-yl)-2-(tert-butoxy)ethyl)carbamate

The compound 4d (28.0 g, 32.79 mmol) was dissolved in ethanol (420 mL), and a solution of sodium acetate (4.04 g, 49.19 mmol) in water (60 mL) was added, and the mixture was stirred and refluxed for 2 hr. It was washed several times with saturated brine, distilled under reduced pressure, and purified by silica gel column chromatography (eluent: 0-30% ethyl acetate in petroleum ether). 6.6 g of milky white solid 4e was obtained (yield: 24.1%).

Step 6: ((R)-1-(5-((S)-1-Amino-3-keto-3-(tritylamino)propyl)-1,2,4-oxadiazole- Preparation of tert-butyl 3-yl)-2-(tert-butoxy)ethyl)carbamate

Compound 4e (6.6 g, 7.89 mmol) was added to dichloromethane (66 mL). The solvent was evaporated under reduced pressure and purified by silica gel column chromatography (eluent: EtOAc: EtOAc

Step 7: Preparation of (S)-(2-ketotetrahydrofuran-3-yl)carbamic acid 4-nitrophenyl ester

The title compound was synthesized in a similar manner to the preparation of the compound 2b in Example 29, in which the H-Thr(O ^t Bu)-O ^t Bu in Example 29 was replaced with (S)-2-keto-3-aminotetrahydrofuran. .

Step 8: ((R)-2-(tert-Butoxy)-1-(5-((S)-3-keto-1-(3-((S)-2-ketotetrahydrofuran-3- Preparation of tert-butyl ester of ureido)-3-(tritylamino)propyl)-1,2,4-oxadiazol-3-yl)ethyl)carbamate

Compound 4f (500 mg, 0.815 mmol) and 4 g were dissolved in tetrahydrofuran (5 mL), triethylamine (9.84 g, 97.26 mmol). The solvent was evaporated under reduced pressure, and ethyl acetate was evaporated, evaporated, evaporated, evaporated, evaporated, evaporated, The ester gave 400 mg of a white foamy solid for 4 h (yield: 66.2%).

Step 9: (S)-3-(3-((R)-1-Amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3-(3-(( Preparation of S)-2-ketotetrahydrofuran-3-yl)ureido)propanamide

Compound 4h (280mg, 0.378mmol) was dissolved in dichloromethane (7mL), trifluoroacetic acid (3.88g, 34.04mmol) was added at room temperature, catalytic amount of triisopropylsilane, stirred at room temperature for 2.5h, distilled under reduced pressure The solvent was removed, dichloromethane and water were added to dissolve, and the organic phase was extracted several times with water, the aqueous phase was combined, and the mixture was washed several times with dichloromethane, and the aqueous phase was lyophilized to obtain a liquid crystal. ¹ H NMR (500 MHz, D ₂ O) δ 6.00 - 5.94 (m, 1H), 4.13 - 4.03 (m, 2H), 3.75 (tt, J = 11.1, 5.4 Hz, 2H), 3.48 (ddd, J = 15.8, 6.3, 3.4 Hz, 1H), 3.34 (ddd, J = 15.1, 10.1, 5.7 Hz, 1H), 2.19 - 2.02 (m, 2H), 1.96 (s, 2H). ESI-MS m/z: 343.3 [M+H] ⁺ .

Example 32 1-(3-((S))-1-amino-1-(3-((R)-1-amino-2-hydroxyethyl)-1,2,4-oxadiazole-5- Preparation of benzyl-3-propyloxy)ureido)cyclopropane-1-carboxylic acid

Step 5a 1-(3-((S)-1-(3-((R))-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)ethyl)-1,2, Preparation of methyl 4-oxadiazol-5-yl)-3-keto-3-(tritylamino)propyl)ureido)cyclopropane-1-carboxylate

The title compound was synthesized in a similar manner to the preparation of compound 4 in Example 31, which was replaced with 1-aminocyclopropane-1-carboxylic acid methyl ester hydrochloride to replace the (S)-2-keto group in the step 4i of Example 31. 3-aminotetrahydrofuran.

Step 5b: 1-(3-((S)-1-(3-((R))-2-(tert-butoxy)-1-((tert-butoxycarbonyl)amino)ethyl)-1,2 Of 4-oxaoxazol-5-yl)-3-keto-3-(tritylamino)propyl)ureido)cyclopropane-1-carboxylic acid

The compound 5a (770 mg, 1.02 mmol) was dissolved in tetrahydrofuran (6 mL), and a solution of lithium hydroxide (85 mg, 2.04 mmol) in water (1.1 mL) was added at room temperature, and the mixture was stirred and refluxed for 3 hr. Ethyl acetate and water were added and dissolved, and the ethyl acetate layer was washed successively with 1M citric acid and brine, dried over anhydrous sodium sulfate, evaporated under reduced pressure and purified by silica gel column chromatography (eluent: petroleum 0-50% ethyl acetate in ether, 0-10% methanol in dichloromethane) gave 180 mg of white solid 5b (yield: 23.8%).

Step 5c: 1-(3-((S)-3-Amino-1-(3-((R)-1-amino-2-hydroxyethyl)-1,2,4-oxadiazole-5- Preparation of benzyl-3-propyloxy)ureido)cyclopropane-1-carboxylic acid

Compound 5b (180 mg, 0.243 mmol) was dissolved in dichloromethane (3 mL), trifluoroacetic acid (1.66 g, 14.58 mmol) and a catalytic amount of triisopropylsilane were added sequentially at room temperature, and the reaction was stirred for 4 h. Distillation, adding dichloromethane and water to dissolve, liquid separation, the organic phase is extracted several times with water, the aqueous phase is combined, and then washed several times with dichloromethane, the aqueous phase is lyophilized, and the liquid phase is purified to obtain compound 32. ¹ H NMR (500 MHz, D ₂ O) δ 5.51 - 5.43 (m, 1H), 4.17 - 4.08 (m, 2H), 3.12 (d, J = 6.4 Hz, 2H), 1.39 (s, 2H), 1.07 (s, 2H). ESI-MS m/z: 343.2 [M+H] ⁺ .

Example 33 1-(3-((R)-3-Amino-1-(3-((S)-1-amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-) Preparation of benzyl-3-propyloxy)ureido)cyclopropane-1-carboxylic acid

The title compound was synthesized in a similar manner to the preparation of compound 5 in Example 32, in which Boc-L-Ser(tBu)-OH in Example 32 was replaced with Boc-D-Ser(tBu)-OH, using Fmoc-D -Asn(Trt)-OH replaces Fmoc-L-Asn(Trt)-OH in Example 5. The crude product was purified by preparative liquid to give the title compound. ¹ H NMR (400 MHz, D ₂ O): δ 5.30 (t, J = 6.1 Hz, 1H), 4.59 (s, 1H), 3.94 (d, J = 4.7 Hz, 2H), 2.95 (d, J = 6.3 Hz, 2H), 1.22 (s, 2H), 0.90 (s, 2H). ESI-MS m/z: 343.1 [M+H] ⁺

Example 34 1-(3-((S)-1-(3-((R))-1-amino-2-hydroxyethyl)-1,2,4-oxadiazol-5-yl)-3 -Carboxypropyl)ureido)cyclopropane-1-carboxylic acid preparation

Use Example Preparation of compound 5 The title compound was synthesized analogous to 32 in which Fmoc-L-Asn (Trt) in Example 32 using ^{Fmoc-L-Glu (O t} Bu) -OH alternative embodiment -OH. The crude product was purified by preparative liquid to give the title compound. _{^{1 H NMR (300MHz, D 2}} O): δ5.02 (s, 1H), 4.05 (s, 2H), 2.30 (d, J = 7.5Hz, 2H), 2.19 (dd, J = 19.8,6.4Hz, 2H), 1.32 (s, 2H), 0.99 (s, 2H). ESI-MS m/z: 343.1 [M+H] ⁺

Example 35 (2S,3R)-2-(3-((S)-3-Amino-1-(3-(1-amino-3-(hydroxymethyl)cyclobutyl)-1,2,4 -Oxadiazole-5-yl)-3-oxopropyl)ureido)-3-hydroxybutyric acid

Step 1 (S)-(1-Fluoro-1,4-dione-4-(tritylamino)butan-2-yl)carbamic acid ((9H-fluoren-9-yl)methyl)ester Preparation

Fmoc-Asn(Trt)-OH (5.0 g, 8.380 mmol) was dissolved in dichloromethane (84 mL), DAST (1.62 g, 10.056 mmol) was slowly added at room temperature, the reaction was stirred at room temperature for 15 min, and the reaction solution was poured into ice water. Quenching, liquid separation, dichloromethane layer washed several times with water, dried over anhydrous sodium sulfate, and evaporated under reduced pressure to give a pale yellow oily liquid, dissolved in a small amount of dichloromethane, recrystallized from a large amount of n-hexane, filtered, filter cake with a small amount The mixture was washed with n-hexane and distilled under reduced pressure to give 4.5 g of white solid (yield: 89.8%).

Step 2: Preparation of methyl 1-amino-3-(hydroxymethyl)cyclobutane-1-carboxylate

The compound 8a (4 g, 27.56 mmol) was dissolved in methanol (40 mL), and the mixture was cooled in an ice bath, and thionyl chloride (6.5 g, 55.13 mmol) was slowly added dropwise at 0 ° C. After the addition was completed, the mixture was heated to reflux for 4 h. The solvent was distilled off under reduced pressure to give a pale yellow oily liquid, which was taken directly to the next step.

Step 3: Preparation of methyl 1-((tert-butoxycarbonyl)amino)-3-(hydroxymethyl)cyclobutane-1-carboxylate

Compound 8b (4g, 25.14mmol) was dissolved in tetrahydrofuran (20mL), and a solution of sodium hydrogencarbonate (8.3g, 88.00mmol) in water (40mL) was added at room temperature, cooled in ice bath, and added to the di-dicarbonate at 0 °C A solution of butyl ester (5.7 g, 23.88 mmol) in tetrahydrofuran (20 mL) was stirred at room temperature overnight. The reaction solvent was evaporated under reduced pressure, and the mixture was dissolved with ethyl acetate and water, and the organic phase was washed several times with water and brine. It was distilled under reduced pressure and purified by silica gel column chromatography to yield 3.7 g of white solid (yield: 56.9%).

Step 4: Preparation of methyl 1-((tert-butoxycarbonyl)amino)-3-(tert-butyldimethylsilyloxy)cyclobutane-1-carboxylate

Compound 8c (700 mg, 2.70 mmol) was dissolved in DMF (7 mL) EtOAc (EtOAc) (EtOAcjjjjjjjjjjjjjj DMF (3.5 mL) solution. The reaction mixture was stirred at room temperature for 4 h, then diluted with EtOAc EtOAc EtOAc. 0-50% ethyl acetate in the ether) gave 900 mg of a colorless oily liquid (yield: 89.3%).

Step 5: Preparation of 1-((tert-Butoxycarbonyl)amino)-3-(tert-butyldimethylsilyloxy)cyclobutane-1-carboxylic acid

The compound 8d (1.6 g, 4.283 mmol) was dissolved in methanol (16 mL), and a solution of lithium hydroxide monohydrate (270 mg, 6.425 mmol) in water (3.2 mL) was added, and the mixture was stirred at room temperature for 3 h, and the solvent was evaporated under reduced pressure. The ethyl ester and water were dissolved and separated, and the organic phase was extracted with water several times. The aqueous phase was combined, the acid was combined with 1M citric acid solution, and then extracted with ethyl acetate. The organic phase was combined, dried over anhydrous Na ₂ SO ₄ and evaporated. There was obtained 1.42 g of a colorless oily liquid 8e (yield: 92.2%).

Step 6: Preparation of 1-((tert-Butoxycarbonyl)amino)-3-(tert-butyldimethylsilyloxy)cyclobutane-1-carboxamide

Compound 8e (2.6 g, 7.231 mmol) was dissolved in tetrahydrofuran (26 mL), N-methylmorpholine (880 mg, 8.673 mmol) was added to form a flocculent solid; ice bath was cooled, and chloroformic acid B was added at -5 °C. Ester (940mg, 8.677mmol), a large amount of solid precipitated, stirred for 0.5h in an ice bath; 3.9mL of 25% aqueous ammonia solution was slowly added, stirred for 3 hours in an ice bath, the solvent was distilled off under reduced pressure, and the remaining solid was dissolved with ethyl acetate and water. Clear and liquid. The organic phase was washed successively with 1 M citric acid, saturated sodium hydrogen carbonate and water, and dried over anhydrous sodium sulfate and evaporated under reduced pressure to give 1.5 g of white solid (yield: 57.9%).

Step 7: Preparation of tert-butyl (3-tert-butyldimethylsilylmethyl-1-cyanocyclobutyl)carbamate

The compound 8f (1.58g, 4.407mmol) was dissolved in pyridine (16mL), cooled in an ice bath, trifluoroacetic anhydride (1.39g, 6.611mmol) was slowly added at -5 °C, and the reaction was stirred for 3 hours in an ice bath, and the reaction solution was poured. The mixture was quenched with EtOAc EtOAc (EtOAc)EtOAc. Agent: 0-15% ethyl acetate in petroleum ether) 1.36 g of a colorless oily liquid 8 g (yield: 90.7%).

Step 8: Preparation of (Z)-(3-tert-butyldimethylsilylmethyl-1-(N'-hydroxymethylindenyl)cyclobutyl)carbamic acid tert-butyl ester

The compound 8g (1.3g, 3.818mmol) was dissolved in ethanol (13mL), and a solution of potassium carbonate (791mg, 5.726mmol) in water (2.6mL), hydroxylamine hydrochloride (398mg, 5.726mmol) The solvent was evaporated under reduced pressure, and the residue was evaporated. In the range of 0-20% ethyl acetate, 700 mg of white solid was obtained (yield: 49.3%).

Step 9: (Z)-(1-(N'-((N ² -((9H-芴-9-yl)methoxy)carbonyl)-N ⁴ -trityl-L-asparagine Preparation of tert-butyl ester of hydroxy)hydroxymethylindenyl)-3-(tert-butyldimethylsilylmethyl)cyclobutylcarbamate

Compound 8h (300 mg, 0.803 mmol) was dissolved in tetrahydrofuran (3 mL). A solution of N-methylmorpholine (240 mg, 2.409 mmol) and compound 8i (960 mg, 1.606 mmol) in tetrahydrofuran (10 mL) was added, and the mixture was stirred at room temperature overnight. The mixture was washed with saturated brine for several times, dried over anhydrous sodium sulfate and evaporated. Yield: 55.8%).

Step 10: (S)-(1-(5-(1-(((9H-芴-9-yl))methoxy)carbonyl)amino)-3-yl-3-yl-3-triphenylmethylamino Of propyl)-1,2,4-oxadiazol-3-yl)-3-(((tert-butyldimethylsilyl)oxy)methyl)cyclobutyl)carbamic acid tert-butyl ester preparation

Compound 8j (1g, 1.050mmol) was dissolved in ^t BuOH (20mL). Sodium acetate (129 mg, 1.575 mmol) was added at room temperature, and the mixture was stirred and refluxed for 3 hr. The solvent was evaporated evaporated vacuo. Purification by silica gel column chromatography (EtOAc:EtOAc:EtOAc

Step 11: (S)-(1-(5-(1-Amino-3-keto-3-(tritylamino)propyl)-1,2,4-oxadiazol-3-yl) Preparation of tert-butyl 3-(((tert-butyldimethylsilyl)oxy)methyl)cyclobutyl)carbamate

Compound 8k (500 mg, 0.535 mmol) was dissolved in dichloromethane (5 mL), and diethylamine (783 mg, 10.7 mmol) was added at room temperature, and the mixture was stirred at room temperature for 4 h. The completion of the reaction was confirmed by TLC analysis. The solvent was evaporated under reduced pressure and purified (EtOAcjjjjjjjjjjj

Step 12: N-(((S)-1-(3-(1-((tert-Butyloxycarbonyl))amino)-3-(((tert-butyldimethylsilyl)oxy)methyl)) Butyl)-1,2,4-oxadiazol-5-yl)-3-keto-3-(tritylamino)propyl)carbamoyl)-O-(tert-butyl)-L -Preparation of threonine tert-butyl ester

The compound 8l (270 mg, 0.379 mmol) was dissolved in tetrahydrofuran (5 mL), and the compound 2b (180 mg, 0.45 mmol), triethylamine (77 mg, 0.758 mmol) was added, and the mixture was stirred at room temperature overnight. The solvent was dissolved in ethyl acetate, and washed successively with 1M citric acid and brine, dried over anhydrous sodium sulfate, and evaporated under reduced pressure and purified by silica gel column chromatography (eluent: 0-15% in petroleum ether) Ethyl acetate) gave 400 mg of white solid (yield: 95.1%).

Step 13: (2S,3R)-2-(3-((S)-3-Amino-1-(3-(1-amino-3-(hydroxymethyl)cyclobutyl)-1,2,4 -Oxadiazole-5-yl)-3-oxopropyl)ureido)-3-hydroxybutyric acid

Compound 8n (350 mg, 0.361 mmol) was dissolved in dichloromethane (7 mL), trifluoroacetic acid (2.06 g, 18.05 mmol) and a catalytic amount of triisopropylsilane were added at room temperature, and the reaction was stirred at room temperature for 5 h. The solvent was distilled off, dichloromethane and water were added to dissolve, and the organic phase was extracted several times with water, the aqueous phase was combined, and the mixture was washed several times with dichloromethane, and the aqueous phase was lyophilized to obtain 70 mg of white solid. (Yield: 37.8%). ¹ H NMR (400 MHz, D ₂ O) δ 5.31 (dd, J = 8.2, 4.7 Hz, 1H), 4.16 - 4.10 (m, 1H), 3.89 (d, J = 3.0 Hz, 1H), 3.61 (d) , J = 6.8 Hz, 2H), 2.99 (d, J = 6.4 Hz, 2H), 2.77 (dt, J = 16.0, 7.9 Hz, 1H), 2.59 - 2.47 (m, 4H), 1.08 (d, J = 6.4 Hz, 3H). ESI-MS m/z: 401.2 [M+H] ⁺ .

Example 36: (S)-4-(3-(1-Amino-3-(hydroxymethyl)cyclobutyl)-1,2,4-oxadiazol-5-yl)-4-(3- Preparation of ((1S,2R)-1-carboxy-2-hydroxypropyl)ureido)butyric acid

The title compound was synthesized in a similar manner to the preparation of the compound in Example 35. Wherein Fmoc-Asn(Trt)-OH was replaced with Fmoc-Glu(OtBu)-OH. ¹ H NMR (400 MHz, D ₂ O) δ 5.02 - 4.97 (m, 1H), 4.25 (dd, J = 6.3, 2.8 Hz, 1H), 4.15 (d, J = 2.6 Hz, 1H), 3.60 (d) , J = 6.7 Hz, 2H), 2.76 (dd, J = 15.4, 8.3 Hz, 1H), 2.60 - 2.44 (m, 6H), 2.24 (dd, J = 13.5, 6.4 Hz, 1H), 2.10 (dd, J = 13.9, 6.8 Hz, 1H), 1.34 (s, 1H), 1.08 (d, J = 6.3 Hz, 3H). ESI-MS m/z: 416.2 [M+H] ⁺ .

Example 37: (S)-3-(3-(1-Amino-3-(hydroxymethyl)cyclobutyl)-1,2,4-oxadiazol-5-yl)-3-(3- Preparation of ((S)-1-carboxy-2-hydroxyethyl)ureido)propionic acid

The title compound was synthesized in a similar manner to the preparation of the compound in Example 35. Wherein Fmoc-Asn(Trt)-OH in Example 8 was replaced with Fmoc-Asp(OtBu)-OH, and H-Thr (OtBu) in Example 35 was replaced with H-Ser(O ^t Bu)-O ^t Bu -OtBu. ¹ H NMR (400 MHz, D ₂ O) δ 5.35 (t, J = 6.0 Hz, 1H), 4.28 (t, J = 4.0 Hz, 1H), 3.86 (dd, J = 11.7, 4.6 Hz, 1H), 3.76 (dd, J = 11.7, 3.6 Hz, 1H), 3.61 (d, J = 6.7 Hz, 2H), 3.13 - 3.08 (m, 2H), 2.78 (dt, J = 15.8, 8.0 Hz, 1H), 2.56 (p, J = 13.8 Hz, 4H). ESI-MS m/z: 388.1 [M+H] ⁺ .

Example 38 (2S,3S)-2-(3-((S)-4-Amino-1-(5-(1-aminocyclopropyl)-1,3,4-oxadiazol-2-yl) Preparation of 4-oxobutyl)ureido)-3-hydroxybutyric acid

Preparation method The same as the preparation method of Example 12, the (2S,3S)-3-hydroxytetrahydropyrrole-2-carboxylic acid in the step 1 of Example 12 was replaced with 1-aminocyclopropane-1-carboxylic acid, and O was The (t-butyl)-L-serine tert-butyl ester is replaced with O-(tert-butyl)-L-threonine tert-butyl ester to obtain the target compound.

Comparative example 1

The compound represented by the following formula (Compound A) was prepared according to the method disclosed in Example 2 of WO2015/033301 (PCT/IB2014/064281), and identified by hydrogen spectrum and mass spectrometry,

The pharmacokinetic characteristics of Compound A and the antitumor effect on the subcutaneous xenograft model of colon cancer CT26 cells were tested using the following Experimental Examples 1 and 2, and the results showed that the bioavailability (F) and inhibition of Compound A were observed. The tumor rate is weaker than some of the compounds of the invention.

In addition, the inventors of the present invention also synthesized and tested Compound No. 12 in Table 3 of WO2015/033301 according to the method disclosed in WO2015/033301, and the results show that the bioavailability and tumor inhibition rate of Compound No. 12 are significantly weaker than the present invention. Compound and Compound A.

Experimental Example 1 Drug Metabolism Experiment

1 experimental material

1.1 compound

The experiment was carried out using the compound of the present invention prepared in the above examples and the compound of Example 2 ("Compound A") in WO2015/033301. The oral drug was dissolved in physiological saline to prepare a clear solution of 0.5 mg/mL, and the intravenous drug was dissolved in physiological saline to prepare a 0.1 mg/mL clear solution.

1.2 animals

Male BALB/c mice, 3 in each group, weighing 18-22 g, were provided by Shanghai Xipuer-Beikai Experimental Animal Co., Ltd.

The test mice were given an environmental adaptation period of 2 to 4 days before the experiment, and were fasted for 8-12 hours before administration, and given water for 2 hours after administration, and fed after 4 hours.

1.3 reagent

Methanol (chromatographically pure): produced by Spectrum;

Acetonitrile (chromatographically pure): produced by Spectrum;

The remaining reagents were all commercially available analytical grades.

1.4 Instrument

American AB company API 4500 triple quadrupole liquid-mass instrument with electrospray ion source (ESI), LC-30AD double pump; SIL-30AC autosampler; CTO-30AC column thermostat; DGU-20A3R Degasser; Analyst QS A01.01 chromatography workstation; Milli-Q ultrapure water (Millipore Inc); Qilinbeier Vortex-5 oscillator; HITACHI CF16R X II benchtop high speed refrigerated centrifuge.

2 experimental methods

1) The mice were fasted but allowed to drink water for 12 hours, and the blank plasma was taken at 0 o'clock;

2) taking the mouse in step 1), administering intragastric administration (IG) to the test compound 10 mg/kg; intravenous (IV) administering the test compound 1 mg/kg;

3) 5 min, 15 min, 30 min, 1 h, 2 h, 4 h, 8 h, 10 h, 24 h after intragastric administration, continuous blood was taken from the fundus venous plexus in an EP tube with heparin distributed, and centrifuged at 8000 rpm/min for 5 min. , frozen at -20 ° C, to be analyzed by LC-MS/MS;

4) Calculate the pharmacokinetic parameters using WinNonlin software according to the plasma concentration-time data obtained in step 3);

3 experimental results:

The pharmacokinetic experimental data are shown in Table 1. The results indicate that after oral administration of the compound of the above examples, there is a certain amount of exposure and a suitable half-life in the plasma of the animal, especially Example 4, Example 5 The compounds of Example 8, Example 6 and Example 22 have very good half-life, area under the curve and bioavailability, have good drug-forming properties, and have good clinical application prospects.

Table 1 Pharmacokinetic data of the compounds of the examples of the invention

Experimental Example 2 In vivo pharmacodynamic experiment

1. Experimental materials

1.1 compound

This experiment was carried out using the compounds prepared according to the examples of the present invention. The negative control group was given physiological saline. Orally administered, the test compound was dissolved in physiological saline to prepare a 2 mg/mL clear solution.

1.2 animals

Female BALB/c mice, 3 in each group, weighing 18-22 g, were provided by Shanghai Xipuer-Beikai Experimental Animal Co., Ltd. The test mice were given an environmental adaptation period of 2 to 4 days before the experiment, and were fasted for 8-12 hours before administration, and given water for 2 hours after administration, and fed after 4 hours.

1.3 positive control

Compound A was prepared according to the method disclosed in Example 2 of WO 2015/033301.

2, experimental methods

After the cells were inoculated and the tumors were grown to an average volume of 40 mm ³ (first round of experiments) or 50 mm ³ (second round of experiments), the animals were randomly divided into groups of 6 each, and each test group was orally administered with 20 mg/kg, one day. Once, continuous administration for 14 days. The changes in body weight of the experimental animals and whether the tumor growth was inhibited or delayed were examined. Tumor diameters were measured with vernier calipers three times a week.

The calculation formula of tumor volume is: V = 0.5a × b ² , and a and b represent the long diameter and short diameter of the tumor, respectively.

The relative tumor growth rate T/C (%) was calculated as: T/C = T _RTV / C _RTV X 100% (T _RTV : treatment group RTV; C _RTV : solvent control group RTV). Relative tumor volume (RTV) was calculated based on the measurement results, RTV = V _t /V ₀ , where V ₀ is the tumor volume at the start of the experiment, and the tumor volume at each measurement of Vt.

The tumor growth inhibition rate TGI (%) was calculated as: TGI = [1 - (the average tumor volume at the end of a treatment group - the average tumor volume at the start of administration of the treatment group) / (the average of the solvent control group at the end of treatment) Tumor volume - mean tumor volume at the start of treatment in the solvent control group)] X 100%.

3. Experimental conclusion

3.1 Weight changes

The compound of the present invention has no effect on the body weight of the mouse colon cancer CT26 cell subcutaneous homologous tumor in the BALB/C mouse model. Table 2 shows the administration of Example 4, Example 5, Example 35 and Compound A. The effect of body weight indicated that the body weight of the control group and each drug-administered group gradually increased during the administration period and was well tolerated.

Table 2 Effect of the compound of the present invention on the body weight of mice after administration

3.2 Anti-tumor efficacy evaluation indicators

The evaluation index of drug efficacy is shown in Table 3. On the 15th day after the first round of experiment started, the average tumor volume of the tumor-bearing mice in the solvent control group reached 3672 mm ³ , and the average tumor volume of the tumor-bearing mice in the other drug-administered groups was average. It is smaller than the average tumor volume of the control group, wherein the compound of Example 4 has a T/C value of 41.5% on the 15th day and a TGI value of 52.4%, indicating that it has a significant inhibitory effect on CT26 colon cancer xenografts, and the effect is obvious. Better than compound A. On the 14th day after the start of the second round of experiment, the average tumor volume of the tumor-bearing mice in the solvent control group reached 1524 mm ³ , and the average tumor volume of the tumor-bearing mice in each of the other test groups was smaller than the average tumor volume of the control group. The compound of Example 5 had a T/C value of 39.0% at day 14 and a TGI value of 63.7%, indicating that it had a significant inhibitory effect on CT26 colon cancer xenografts.

Table 3 anti-tumor efficacy evaluation indicators

While the invention has been described hereinabove, it will be understood by those skilled in the art that various modifications and changes of the invention may be made without departing from the spirit and scope of the invention. The scope of the invention is not limited to the details described above, but rather to the claims.

Claims (10)

1. a compound of the formula A or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug,

   

   among them:

   X and Y are each independently selected from N, O and S, and when X is N, Y is selected from O and S; when X is O or S, Y is N; when Y is N, X is selected from O and S; When Y is O or S, X is N;

   When X is N, Y is selected from O and S or Y is O or S, and X is N, the group

   

   for

   

   When X is O or S, Y is N or Y is N, and X is selected from O and S, the group

   

   for

   

   R _{1 is} selected from the side chains of the amino acids Ser and Thr;

   R _{2 is} selected from the group consisting of the amino acid Ser and Thr residues;

   R _{3 is} selected from the group consisting of H, —(CH ₂ ) _m C(O)OR ₄ , —(CH ₂ ) _m C(O)N(R ₅ )(R ₆ ) and —(CH ₂ ) _m CN, wherein R ₄ , R ₅ , R ₆ are each independently selected from H and alkyl, and m is 0, 1, 2, 3 or 4;

   n is 1, 2, 3 or 4.
2. The compound of the formula A according to claim 1, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein the formula A has the structure of the following formula II,

   

   Wherein: Q is selected from O and S; and R ₁ , R ₂ and R ₃ are as defined in claim 1.
3. The compound of the formula A according to claim 1, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein the formula A has the structure of the following formula I,

   

   Wherein: Q is selected from O and S; and R ₁ , R ₂ and R ₃ are as defined in claim 1.
4. A compound of the formula A according to any one of claims 1 to 3, or a stereoisomer thereof, a pharmaceutically acceptable salt, a solvate, a crystal or a prodrug thereof, wherein:

   R _{1 is} selected from

   

   R _{2 is} selected from

   

   R _{3 is} selected from the group consisting of H, —(CH ₂ ) _m C(O)OR ₄ , —(CH ₂ ) _m C(O)N(R ₅ )(R ₆ ) and —(CH ₂ ) _m CN, wherein R ₄ , R ₅ and R ₆ are each independently selected from H and C _1-6 alkyl, and m is 1, 2, 3 or 4;

   n is 1, 2, 3 or 4.
5. A compound of the formula A according to any one of claims 1 to 3, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein:

   R _{1 is} selected from

   

   R _{2 is} selected from

   

   R _{3 is} selected from H,

   

   with

   n is 1, 2, 3 or 4.
6. The compound of the formula A according to claim 1, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, wherein the compound is a compound selected from the group consisting of:

   

   
7. A process for the preparation of a compound of the formula A according to claim 2, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, comprising the steps of:

   

   (1) a compound of the formula ia and a compound of the formula iib are subjected to a condensation reaction to form a compound of the formula iic;

   (2) cyclization of a compound of formula iic to give a compound of formula iid;

   (3) a compound of the formula iid is reacted with an amine compound to give a compound of the formula iie;

   (4) a compound of the formula iie and a compound of the formula if subjected to nucleophilic substitution to give a compound of the formula iig;

   (5) under acidic conditions, a compound of formula iig is hydrolyzed to give a compound of formula II;

   Wherein: Pg ₁ represents a protecting group of R ₁ ; Pg ₂ represents a protecting group of R ₂ ; Pg ₃ represents a protecting group of R ₃ or is absent; and Pg ₄ and Pg ₅ represent an amino protecting group.
8. A process for the preparation of a compound of the formula A according to claim 3, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, comprising the steps of:

   

   (1) a compound of the formula ia and a compound of the formula ib are subjected to a condensation reaction to form a compound of the formula ic;

   (2) cyclizing a compound of the formula ic to give a compound of the formula id;

   (3) a compound of the formula id is reacted with an amine compound to give a compound of the formula IE;

   (4) a nucleophilic substitution reaction of a compound of the formula IE with a compound of the formula i to give a compound of the formula ig;

   (5) under acidic conditions, a compound of formula ig is hydrolyzed to give a compound of formula I;

   Wherein: Pg ₁ represents a protecting group of R ₁ ; Pg ₂ represents a protecting group of R ₂ ; Pg ₃ represents a protecting group of R ₃ or is absent; and Pg ₄ and Pg ₅ represent an amino protecting group.
9. A pharmaceutical composition comprising a compound according to any one of claims 1 to 6, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, and a pharmaceutically acceptable carrier.
10. A compound according to any one of claims 1 to 6, or a stereoisomer, pharmaceutically acceptable salt, solvate, crystal or prodrug thereof, or a pharmaceutical composition according to claim 9 Use in medicines for treating cancer or infectious diseases.