3-Hydroxy-5-pregnane-20-one derivatives and uses thereof

Abstract

The present invention provides 3-hydroxy-5-pregnane-20-one derivatives of Formula I or pharmaceutically acceptable salts thereof, and pharmaceutical compositions containing such derivatives or pharmaceutically acceptable salts. The derivatives or pharmaceutically acceptable salts thereof, or pharmaceutical compositions containing such derivatives or salts, can be used to prepare medicaments for treating diseases caused by central nervous system abnormalities. #imgabs0#

Description

Technical Field

[0001] The present invention relates to the field of medicinal chemistry; specifically, the present invention relates to 3-hydroxy-5-pregnane-20-one derivatives represented by formula (I) and their use in preparing drugs for preventing or treating central nervous system disorders. Background Art

[0002] Neuroactive steroids are steroids active in neural tissue. They play important regulatory roles in the human body and primarily include progesterone, pregnenolone, and allopregnanolone. Progesterone, pregnenolone, and allopregnanolone are all produced from cholesterol through different metabolic pathways. Cholesterol is transported from the outer to the inner mitochondrial membrane mediated by the 18kDa translocator protein. Cholesterol is metabolized by cytochrome P450 cholesterol side-chain cleavage enzyme to pregnenolone, which is then metabolized to progesterone by 3β-hydroxysteroid dehydrogenase. This is further metabolized to allopregnanolone by a series of enzymatic reactions mediated by 5α-reductase and 3α-hydroxysteroid dehydrogenase. Neuroactive steroids can be used as anesthetics, sedatives, hypnotics, anxiolytics, antidepressants, and anticonvulsants.

[0003] Allopregnanolone has been a hot topic in recent years. As early as 1986, some people pointed out that allopregnanolone is a GABA A It is a positive modulator of GABA receptors. However, it was not until 2006 that people discovered that allopregnanolone may mainly interact with GABA A The α and β subunits of the receptor bind to increase the opening frequency of the chloride ion channel on the receptor, reduce nerve excitability, and thus produce a calming and anti-anxiety effect.

[0004] Literature reports that levels of progesterone and its metabolites vary during different phases of the menstrual cycle. Prior to menstruation, decreased levels of progesterone and its metabolites can cause premenstrual syndrome (PMS), a condition characterized by recurring symptoms before the menstrual cycle that disappear afterward, such as stress, anxiety, and migraines. Postpartum depression has also been linked to abnormal levels of progesterone and its metabolites. Plasma allopregnanolone concentrations increase in healthy pregnant women as pregnancy progresses, but drop dramatically after delivery.

[0005] Studies have shown that a decrease in allopregnanolone levels is believed to be closely related to the occurrence and development of many mental disorders such as anxiety, depression and tremor, and exogenous administration of allopregnanolone can significantly improve the above-mentioned mental symptoms.

[0006] However, allopregnanolone has low water solubility, poor oral availability, and a plasma half-life of approximately 45 minutes in humans, leading to rapid metabolism. Zulresso, a water-soluble, sulfobutyl-β-cyclodextrin-based formulation of allopregnanolone, is marketed and produces stable physiological concentrations of allopregnanolone via intravenous injection. However, Brexanolone requires an intravenous infusion of up to 60 hours, resulting in poor patient compliance.

[0007] Therefore, clinically, a solution is needed that can improve solubility, reduce administration time, and maintain a stable physiological concentration of pregnanolone in the body for a long time. Summary of the Invention

[0008] The present invention provides a 3-hydroxy-5-pregnane-20-one derivative that can be used to prepare a medicament for preventing or treating central nervous system disorders. The derivative has improved solubility, is stable in storage, is convenient to administer, and has high patient compliance.

[0009] In a first aspect, the present invention provides a compound of formula I, or a pharmaceutically acceptable salt thereof:

[0010]

[0011] Where,

[0012] R 1 and R 2 Each is independently H, substituted or unsubstituted C1-C 10 Alkyl, substituted or unsubstituted cycloalkyl; R 3 is H, halogen, hydroxy, amino, nitro, or thiol; or, R 2 and R 3 Connected to form a 5-6 membered saturated or unsaturated heterocyclic ring;

[0013] a and b are each independently an integer from 0 to 3.

[0014] In a specific embodiment, R 3 is amino or H.

[0015] In a specific embodiment, the compound represented by Formula I is a compound represented by Formula I-1, I-2, I-3 or I-4:

[0016]

[0017] Where R 1 , R 2 , R 3 , a, b are as described above.

[0018] In a preferred embodiment, R 1 and R2 Each is independently H, a substituted or unsubstituted C1-C8 alkyl group; wherein the substituent of the alkyl group is selected from C1-C6 alkyl, aryl, hydroxy-substituted aryl, amino-substituted aryl, halogen-substituted aryl, carboxyl-substituted aryl, heteroaryl, hydroxy-substituted heteroaryl, amino-substituted heteroaryl, halogen-substituted heteroaryl, carboxyl-substituted heteroaryl, amino, methylamino, dimethylamino, hydroxy, sulfhydryl, methylthio, amide, guanidino or carboxyl.

[0019] In a preferred embodiment, R 1 and R 2 Each is independently H, substituted or unsubstituted C1 alkyl, substituted or unsubstituted C2 alkyl, substituted or unsubstituted C3 alkyl, substituted or unsubstituted C4 alkyl, substituted or unsubstituted C5 alkyl, substituted or unsubstituted C6 alkyl, substituted or unsubstituted C7 alkyl, substituted or unsubstituted C8 alkyl; wherein the substituent of the alkyl group is selected from methyl, ethyl, propyl, butyl, isopropyl, isobutyl, tert-butyl, phenyl, hydroxy-substituted phenyl, indolyl, imidazolyl, amino, hydroxyl, thiol, methylthio, amide, guanidino, methylamino, dimethylamino or carboxyl.

[0020] In a preferred embodiment, R 1 and R 2 Each is independently H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted isopropyl, substituted or unsubstituted n-butyl, substituted or unsubstituted tert-butyl, substituted or unsubstituted 2-isobutyl, substituted or unsubstituted 1-isobutyl; wherein the substituent is selected from methyl, ethyl, propyl, butyl, isopropyl, isobutyl, tert-butyl, phenyl, 2-hydroxyphenyl, 3-hydroxyphenyl, 4-hydroxyphenyl, indolyl, imidazolyl, amino, hydroxyl, thiol, methylthio, amido, methylamino, dimethylamino, guanidino or carboxyl.

[0021] In a preferred embodiment, R 1 and R 2 Each is independently H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted isopropyl, substituted or unsubstituted n-butyl, substituted or unsubstituted tert-butyl, substituted or unsubstituted 2-isobutyl, substituted or unsubstituted 1-isobutyl; wherein the substituent is selected from methyl, ethyl, propyl, butyl, isopropyl, isobutyl, tert-butyl, amino, hydroxyl, sulfhydryl, methylthio, amide, methylamino, dimethylamino, guanidino or carboxyl.

[0022] In a preferred embodiment, R 1 and R 2and each independently represents H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, amide-substituted methyl, phenyl-substituted methyl, hydroxy-substituted methyl, carboxyl-substituted methyl, mercapto-substituted methyl, imidazole-substituted methyl, indole-substituted methyl, p-hydroxyphenyl-substituted methyl, methylthio-substituted methyl, guanidino-substituted methyl, amino-substituted methyl, amide-substituted ethyl, hydroxy-substituted ethyl, carboxyl-substituted ethyl, mercapto-substituted ethyl, imidazole-substituted ethyl, indole-substituted ethyl, p-hydroxyphenyl-substituted ethyl, methylthio-substituted ethyl, guanidino-substituted ethyl. substituted propyl group, a propyl group substituted with amino, an ethyl group substituted with amino, an amide substituted propyl group, a hydroxy substituted propyl group, a carboxy substituted propyl group, a mercapto substituted propyl group, an imidazole substituted propyl group, an indole substituted propyl group, a p-hydroxyphenyl substituted propyl group, a methylthio substituted propyl group, a guanidino substituted propyl group, an amino substituted propyl group, a dimethylamino substituted propyl group, a methyl substituted propyl group, an amide substituted butyl group, a hydroxy substituted butyl group, a carboxy substituted butyl group, a mercapto substituted butyl group, an imidazole substituted butyl group, an indole substituted butyl group, a p-hydroxyphenyl substituted butyl group, a methylthio substituted butyl group, a guanidino substituted butyl group, or an amino substituted butyl group.

[0023] In a preferred embodiment, R 1 and R 2 Each is independently H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, amide-substituted methyl, hydroxy-substituted methyl, carboxyl-substituted methyl, mercapto-substituted methyl, methylthio-substituted methyl, guanidino-substituted methyl, amino-substituted methyl, amide-substituted ethyl, hydroxy-substituted ethyl, carboxyl-substituted ethyl, mercapto-substituted ethyl, methylthio-substituted ethyl, guanidino-substituted ethyl, amino-substituted ethyl, amide-substituted propyl, hydroxy-substituted propyl, carboxyl-substituted propyl, mercapto-substituted propyl, methylthio-substituted propyl, guanidino-substituted propyl, amino-substituted propyl, dimethylamino-substituted propyl, methyl-substituted propyl, amide-substituted butyl, hydroxy-substituted butyl, carboxyl-substituted butyl, mercapto-substituted butyl, methylthio-substituted butyl, guanidino-substituted butyl, or amino-substituted butyl.

[0024] In a specific embodiment, R 1 and R 2 At least one of them is isopropyl.

[0025] In a preferred embodiment, R 1 and R 2each independently represents H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, amide-substituted methyl, phenyl-substituted methyl, hydroxy-substituted methyl, carboxyl-substituted methyl, mercapto-substituted methyl, imidazole-substituted methyl, indole-substituted methyl, p-hydroxyphenyl-substituted methyl, methylthio-substituted methyl, guanidino-substituted methyl, amino-substituted methyl, amide-substituted ethyl, hydroxy-substituted ethyl, carboxyl-substituted ethyl, mercapto-substituted ethyl, imidazole-substituted ethyl, indole-substituted ethyl, p-hydroxyphenyl-substituted ethyl, methylthio-substituted ethyl, guanidino-substituted ethyl , amino-substituted ethyl, amide-substituted propyl, hydroxy-substituted propyl, carboxyl-substituted propyl, mercapto-substituted propyl, imidazole-substituted propyl, indole-substituted propyl, p-hydroxyphenyl-substituted propyl, methylthio-substituted propyl, guanidino-substituted propyl, amino-substituted propyl, dimethylamino-substituted propyl, methyl-substituted propyl, amide-substituted butyl, hydroxy-substituted butyl, carboxyl-substituted butyl, mercapto-substituted butyl, imidazole-substituted butyl, indole-substituted butyl, p-hydroxyphenyl-substituted butyl, methylthio-substituted butyl, guanidino-substituted butyl, or amino-substituted butyl; and R 1 、R 2 At least one of them is isopropyl; R 3 is H, halogen, hydroxy, amino, nitro, or mercapto; a and b are each independently selected from 0, 1, 2, or 3.

[0026] In a specific embodiment, R 1 It is isopropyl.

[0027] In a preferred embodiment, R 2is selected from H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, amide-substituted methyl, phenyl-substituted methyl, hydroxy-substituted methyl, carboxyl-substituted methyl, mercapto-substituted methyl, imidazole-substituted methyl, indole-substituted methyl, p-hydroxyphenyl-substituted methyl, methylthio-substituted methyl, 2-amide-ethyl, 1-hydroxyethyl, 2-hydroxyethyl, 2-carboxyethyl, mercapto-substituted ethyl, imidazole-substituted ethyl, indole-substituted ethyl, p-hydroxyphenyl-substituted ethyl, 2-methylthioethyl, guanidino-substituted ethyl, 2-aminoethyl, amide-substituted propyl, hydroxy-substituted propyl, carboxyl-substituted propyl, mercapto-substituted propyl, imidazole-substituted propyl, indole-substituted propyl, p-hydroxyphenyl-substituted propyl, methylthio-substituted propyl, 1-guanidinopropyl, 2-guanidinopropyl, 3-guanidinopropyl, 1-aminopropyl, 2-aminopropyl, 3-aminopropyl, 1-dimethylaminopropyl, 2-dimethylaminopropyl, 3-dimethylaminopropyl, 1-methylpropyl, 2-methylpropyl, amide-substituted butyl, hydroxy-substituted butyl, carboxyl-substituted butyl, mercapto-substituted butyl, imidazole-substituted butyl, indole-substituted butyl, p-hydroxyphenyl-substituted butyl, methylthio-substituted butyl, guanidino-substituted butyl, 1-aminobutyl, 2-aminobutyl, 3-aminobutyl or 4-aminobutyl.

[0028] In a preferred embodiment, R 2 is selected from H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, amide-substituted methyl, phenyl-substituted methyl, hydroxy-substituted methyl, carboxyl-substituted methyl, mercapto-substituted methyl, imidazole-substituted methyl, indole-substituted methyl, p-hydroxyphenyl-substituted methyl, methylthio-substituted methyl, 2-amidoethyl, 1-hydroxyethyl, 2-carboxyethyl, 2-methylthioethyl, 3-guanidinopropyl, 3-dimethylaminopropyl, 1-methylpropyl, 2-methylpropyl or 4-aminobutyl.

[0029] In a preferred embodiment, R 3 Selected from H or amino.

[0030] In a preferred embodiment, R 2 and R 3 The groups are connected to form a 5-6 membered saturated or unsaturated heterocyclic ring; preferably a 5-membered saturated or unsaturated heterocyclic ring containing one heteroatom; more preferably a 5-membered saturated heterocyclic ring containing one heteroatom; and most preferably a pyrrolidinyl group.

[0031] In a preferred embodiment, a and b are each independently selected from 0, 1, 2 or 3.

[0032] In a preferred embodiment, a is selected from 0, and b is selected from 0 or 1.

[0033] In a preferred embodiment, R1 isopropyl; R 2 is selected from H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, amide-substituted methyl, phenyl-substituted methyl, hydroxy-substituted methyl, carboxyl-substituted methyl, mercapto-substituted methyl, imidazole-substituted methyl, indole-substituted methyl, p-hydroxyphenyl-substituted methyl, methylthio-substituted methyl, 2-amidoethyl, 1-hydroxyethyl, 2-hydroxyethyl, 2-carboxylethyl, mercapto-substituted ethyl, imidazole-substituted ethyl, indole-substituted ethyl, p-hydroxyphenyl-substituted ethyl, 2-methylthioethyl, guanidino-substituted ethyl, 2-aminoethyl, amide-substituted propyl, hydroxy-substituted propyl, carboxyl-substituted propyl, mercapto-substituted propyl, imidazole-substituted R is substituted with butyl, butyl substituted with oxazole, propyl substituted with indole, propyl substituted with p-hydroxyphenyl, propyl substituted with methylthio, 1-guanidinopropyl, 2-guanidinopropyl, 3-guanidinopropyl, 1-aminopropyl, 2-aminopropyl, 3-aminopropyl, 1-dimethylaminopropyl, 2-dimethylaminopropyl, 3-dimethylaminopropyl, 1-methylpropyl, 2-methylpropyl, amide-substituted butyl, hydroxy-substituted butyl, carboxyl-substituted butyl, mercapto-substituted butyl, imidazole-substituted butyl, indole-substituted butyl, p-hydroxyphenyl-substituted butyl, methylthio-substituted butyl, guanidino-substituted butyl, 1-aminobutyl, 2-aminobutyl, 3-aminobutyl, or 4-aminobutyl; R 3 is selected from H, or amino; a, b are each independently selected from 0, 1, 2 or 3.

[0034] In a preferred embodiment, R 1 isopropyl; R 2 R is selected from H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, amide-substituted methyl, phenyl-substituted methyl, hydroxy-substituted methyl, carboxyl-substituted methyl, mercapto-substituted methyl, imidazole-substituted methyl, indole-substituted methyl, p-hydroxyphenyl-substituted methyl, methylthio-substituted methyl, 2-amidoethyl, 1-hydroxyethyl, 2-carboxyethyl, 2-methylthioethyl, 3-guanidinopropyl, 3-dimethylaminopropyl, 1-methylpropyl, 2-methylpropyl or 4-aminobutyl; 3 is selected from H or amino; a is selected from 0; b is selected from 0 or 1.

[0035] In a preferred embodiment, R 1 isopropyl; R 2 and R 3 connect to form a 5-6 membered saturated or unsaturated heterocyclic ring; a and b are each independently selected from 0, 1, 2 or 3.

[0036] In a preferred embodiment, R 2 and R 3connected to form a 5-membered saturated or unsaturated heterocyclic ring containing one heteroatom; preferably a 5-membered saturated heterocyclic ring containing one heteroatom; more preferably a pyrrolidinyl group; a is selected from 0; b is selected from 0 or 1.

[0037] In a second aspect, the present invention provides a compound selected from the group consisting of:

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044] In a third aspect, the present invention provides a compound selected from the group consisting of:

[0045]

[0046] In a fourth aspect, the present invention provides a pharmaceutical composition comprising a therapeutically effective dose of the compound according to the first to third aspects or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier and / or excipient.

[0047] In a preferred embodiment, the pharmaceutical composition is a pharmaceutical composition for preventing or treating central nervous system disorders.

[0048] In a preferred embodiment, the central nervous system disorder includes but is not limited to tremor, sleep disorder, depression, dysthymic disorder, bipolar disorder, anxiety disorder, stress reaction, post-traumatic stress disorder, obsessive-compulsive disorder, schizophrenia, schizoaffective disorder, epilepsy, seizures, memory impairment and / or cognitive impairment, dementia, movement disorder, personality disorder, autism, single etiology autism, pain, traumatic brain injury, vascular disease, substance abuse disorder and / or withdrawal syndrome or tinnitus; or

[0049] The central nervous system disorders include, but are not limited to, essential tremor, epilepsy, clinical depression, postpartum or postpartum depression, atypical depression, psychotic major depressive disorder, catatonic depression, seasonal affective disorder, dysthymia, double depression, depressive personality disorder, recurrent brief depression, minor depressive disorder, bipolar disorder or manic-depressive disorder, post-traumatic stress disorder, depression due to chronic medical conditions, treatment-resistant depression, refractory depression, suicidal tendencies, suicidal ideation, suicidal behavior, traumatic brain injury, generalized anxiety disorder, social anxiety disorder, attention deficit hyperactivity disorder, dementia, Huntington's disease, Parkinson's disease, neuropathic pain, injury-related pain syndrome, acute pain, long-term pain, stroke, ischemia, vascular malformations, addiction to opiates, cocaine and / or alcohol, or insomnia.

[0050] In a fifth aspect, the present invention provides use of the compound or pharmaceutically acceptable salt thereof according to the first to third aspects, or the pharmaceutical composition according to the fourth aspect, in the preparation of a drug for preventing or treating central nervous system disorders.

[0051] In a specific embodiment, the central nervous system disorder includes but is not limited to tremor, sleep disorder, depression, dysthymic disorder, bipolar disorder, anxiety disorder, stress reaction, post-traumatic stress disorder, obsessive-compulsive disorder, schizophrenia, schizoaffective disorder, epilepsy, seizures, memory impairment and / or cognitive impairment, dementia, movement disorder, personality disorder, autism, monoetiology autism, pain, traumatic brain injury, vascular disease, substance abuse disorder and / or withdrawal syndrome or tinnitus; or

[0052] The central nervous system disorders include, but are not limited to, essential tremor, epilepsy, clinical depression, postpartum or postpartum depression, atypical depression, psychotic major depressive disorder, catatonic depression, seasonal affective disorder, dysthymia, double depression, depressive personality disorder, recurrent brief depression, minor depressive disorder, bipolar disorder or manic-depressive disorder, post-traumatic stress disorder, depression due to chronic medical conditions, treatment-resistant depression, refractory depression, suicidal tendencies, suicidal ideation, suicidal behavior, traumatic brain injury, generalized anxiety disorder, social anxiety disorder, attention deficit hyperactivity disorder, dementia, Huntington's disease, Parkinson's disease, neuropathic pain, injury-related pain syndrome, acute pain, long-term pain, stroke, ischemia, vascular malformations, addiction to opiates, cocaine and / or alcohol, or insomnia.

[0053] In a sixth aspect, the present invention provides the compound or pharmaceutically acceptable salt thereof according to the first to third aspects, or the pharmaceutical composition according to the second aspect, for use as a drug for preventing or treating central nervous system disorders.

[0054] In the seventh aspect, the present invention provides a method for preventing or treating central nervous system disorders, which comprises administering a therapeutically effective amount of the compound or pharmaceutically acceptable salt thereof described in the first to third aspects, or the pharmaceutical composition described in the fourth aspect to a subject in need thereof.

[0055] In a preferred embodiment, the subject is a mammal, preferably a human.

[0056] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features described in detail below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be listed here one by one. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Shown are the pharmacokinetic profiles of the compounds of the present invention after oral administration to male rats. DETAILED DESCRIPTION

[0058] The inventors have discovered that allopregnanolone compounds have poor water solubility and need to be formulated into a cyclodextrin aqueous solution for clinical use, and require a long injection time for effectiveness. After extensive and in-depth research, the inventors unexpectedly discovered that formulating allopregnanolone compounds into specific derivatives can significantly improve the water solubility of such compounds, provide a certain degree of storage stability in aqueous solution, and allow for the production of long-acting, sustained-release formulations with minimal individual variability after administration. Preparations made from the derivatives of the present invention can maintain effective physiological concentrations of allopregnanolone in the body for a long time and are easy to administer, thereby having advantages such as improved patient compliance. This is the basis for the completion of the present invention.

[0059] definition

[0060] Unless stated otherwise, the terms used in the specification and claims have the following meanings.

[0061] The carbon, hydrogen, oxygen, sulfur, nitrogen or halogen involved in the groups and compounds of the present invention include their isotopes, and the carbon, hydrogen, oxygen, sulfur, nitrogen or halogen involved in the groups and compounds of the present invention are optionally further replaced by one or more of their corresponding isotopes, wherein the isotopes of carbon include 12 C. 13 C and 14 C, hydrogen isotopes include protium (H), deuterium (D, also known as heavy hydrogen), tritium (T, also known as super tritium), oxygen isotopes include 16 O. 17 O and 18 O, sulfur isotopes include 32 S. 33 S. 34 S and36 S, nitrogen isotopes include 14 N and 15 N, fluorine isotopes include 19 F, chlorine isotopes include 35 Cl and 37 Isotopes of Cl, bromine include 79 Br and 81 Br.

[0062] The term "alkyl" as used herein has the meaning commonly understood by those skilled in the art, specifically referring to a straight or branched saturated group composed of carbon and hydrogen and having a specified number of carbon atoms. 10 Alkyl refers to a straight or branched chain alkyl group having 1 to 10 carbon atoms, including but not limited to: n-methyl, n-ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, etc.

[0063] As used herein, the term "cycloalkyl" refers to a monocyclic, fused, spirocyclic, or bridged ring composed entirely of carbon, including, but not limited to, cyclopropane, cyclobutane, cyclopentane, spiro[3.4]octane, bicyclo[3.1.1]hexane, and the like.

[0064] The term "5-6 membered saturated or unsaturated heterocycle" as used herein refers to a substituted or unsubstituted saturated or unsaturated non-aromatic ring system containing at least 1 or 2 atoms or groups selected from N, O, S, S(=O) or S(=O)2, wherein the non-aromatic ring system contains 5 or 6 ring atoms; non-limiting examples include azacyclopentyl, azacyclohexyl, 1,3-dioxolane, 1,4-dioxolane, 1,3-dioxolane, cyclopentyl, 1,3-dioxacyclohexyl, 1,3-dithiocyclohexyl, morpholinyl, piperazinyl, pyridinyl, furanyl, thienyl, pyrrolyl, pyranyl, N-alkylpyrrolyl, pyrimidinyl, pyrazinyl, pyridazinyl, imidazolyl, piperidinyl, thiomorpholinyl, dihydropyran, thiadiazolyl, oxazolyl, oxadiazolyl, pyrazolyl, 1,4-dioxadienyl, 2H-1,2-oxazinyl or 2,5-dihydrothienyl, etc.

[0065] The term "halogen" as used herein refers to F, Cl, Br, and I.

[0066] As used herein, the term "pharmaceutically acceptable salt" refers to those salts which, within the scope of sound medical judgment, are suitable for contact with the tissues of humans and lower animals without excessive toxicity, irritation, allergic response, and the like, and are commensurate with a reasonable benefit / risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, Berge et al. describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences (1977) 66: 1-19. Pharmaceutically acceptable salts of the compounds of the present invention include salts derived from suitable inorganic and organic acids and bases. Examples of pharmaceutically acceptable non-toxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, and perchloric acid, or salts formed with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, or malonic acid, or salts formed using methods used in the art, for example, ion exchange methods. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, gluconate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate, and the like. Pharmaceutically acceptable salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium and N+(C1-4 alkyl)4 salts. Representative alkali metal or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium salts, and the like. Further pharmaceutically acceptable salts include non-toxic ammonium salts, quaternary ammonium salts and amine cations formed using counterions, such as halides, hydroxides, carboxylates, sulfates, phosphates, nitrates, lower alkyl sulfonates and aryl sulfonates, if appropriate.

[0067] 3-Hydroxy-5-pregnane-20-one derivative of the present invention and preparation method thereof

[0068] To achieve the purpose of the present invention, the present inventors derivatized the allopregnanolone compound, 3-hydroxy-5-pregnane-20-one, to obtain the 3-hydroxy-5-pregnane-20-one derivative shown in Formula I:

[0069]

[0070] Where R 1 and R 2Each is independently H, substituted or unsubstituted C1-C 10 Alkyl, substituted or unsubstituted cycloalkyl; R 3 is H, halogen, hydroxy, amino, nitro, or thiol; or R 2 and R 3 They are connected to form a 5-6 membered saturated or unsaturated heterocyclic ring; a and b are each independently an integer of 0-3.

[0071] Based on the teachings of the present invention and conventional technical means in the field, those skilled in the art will know that the compound represented by the above formula I can be further decomposed into compounds represented by formula I-1 or I-2 or I-3 or I-4:

[0072]

[0073] The compounds described herein may include one or more asymmetric centers and may therefore exist in a variety of isomeric forms, for example, enantiomers and / or diastereomeric forms. For example, the compounds described herein may be individual enantiomers, diastereomers, or geometric isomers, or may be in the form of mixtures of stereoisomers, including racemic mixtures and mixtures enriched in one or more stereoisomers. Isomers can be separated from the mixture by methods known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts; or preferred isomers can be prepared by asymmetric synthesis. The present invention further includes the compounds described herein as individual isomers substantially free of other isomers, or as mixtures of multiple isomers.

[0074] The present inventors unexpectedly discovered that the 3-hydroxy-5-pregnane-20-one derivatives of the present invention have improved water solubility and can maintain a certain stability when stored in a glucose aqueous solution; in particular, when R 1 or R 2 When R is isopropyl, it has significantly improved water solubility. After further research, the inventors found that the 3-hydroxy-5-pregnane-20-one derivatives of the present invention can have excellent pharmacokinetic properties; in particular, when R in the 3-hydroxy-5-pregnane-20-one derivatives of Formula I of the present invention is 1 When the group is isopropyl, the pharmacokinetic properties of the derivative are better than those of the prototype drug and other derivatives with similar structures.

[0075] Those skilled in the art are aware that while esterification is a commonly used modification method in prodrug design, a major problem facing ester prodrugs is the difficulty in predicting their pharmacokinetic profile. Furthermore, due to the relatively slow and incomplete biotransformation of substituted or unsubstituted alkyl esters in human blood, the bioavailability of these ester prodrugs is often lower than expected. In other words, it is unpredictable how the esterification process will be performed and whether the resulting prodrug will possess the desired properties. Therefore, the excellent pharmacokinetic properties of the 3-hydroxy-5-pregnane-20-one derivatives of the present invention are highly unexpected.

[0076] Based on the teachings of the present invention and common knowledge in the field of chemical synthesis, those skilled in the art will know how to obtain the 3-hydroxy-5-pregnane-20-one derivatives of the present invention. For example, the allopregnanolone compound represented by the following formula is reacted with a corresponding organic acid to prepare the 3-hydroxy-5-pregnane-20-one derivative:

[0077]

[0078] Allopregnanolone used in the preparation of the compounds of the present invention is commercially available or can be prepared according to known methods.

[0079] Pharmaceutical composition of the present invention

[0080] The present inventors have discovered that the 3-hydroxy-5-pregnane-20-one derivatives of the present invention can be hydrolyzed under appropriate conditions, such as the action of esterases in the body, after being administered to a recipient, thereby releasing active allopregnanolone. Therefore, the 3-hydroxy-5-pregnane-20-one derivatives of the present invention or compositions containing the same can be used to prepare drugs for diseases caused by abnormalities in the central nervous system. Diseases caused by abnormalities in the central nervous system include, but are not limited to, tremors, epilepsy, depression or anxiety disorders. In more detail, the central nervous system disorders include, but are not limited to, essential tremor, epilepsy, clinical depression, postpartum or postpartum depression, atypical depression, psychotic major depression, catatonic depression, seasonal affective disorder, dysthymia, double depression, depressive personality disorder, recurrent brief depression, mild depressive disorder, bipolar disorder or manic-depressive disorder, post-traumatic stress disorder, depression caused by chronic medical conditions, treatment-resistant depression, refractory depression, suicidal tendencies, suicidal ideation or suicidal behavior.

[0081] In view of this, the present invention also provides a pharmaceutical composition comprising the above-mentioned 3-hydroxy-5-pregnane-20-one derivative of the present invention and an optional pharmaceutically acceptable carrier. As used herein, the term "composition" is intended to encompass a product comprising specific ingredients in specific amounts, as well as any product produced directly or indirectly by the combination of specific ingredients in specific amounts; and a pharmaceutically acceptable carrier refers to a carrier, diluent, or excipient that does not cause significant irritation to an organism and does not interfere with the biological activity and properties of the administered compound; that is, the carrier, diluent, or excipient must be compatible with the other ingredients of the formulation and not harmful to the recipient thereof.

[0082] The pharmaceutical compositions of the present invention can be prepared using methods well known to those skilled in the art. For example, the compounds of the present invention can be mixed with a pharmaceutically acceptable carrier, diluent, or excipient to prepare the corresponding pharmaceutical composition. Furthermore, those skilled in the art can formulate the compounds or pharmaceutical compositions of the present invention into various suitable dosage forms, including but not limited to forms suitable for rectal administration, transdermal administration, intradermal administration, intrathecal administration, subcutaneous administration, intravenous administration, intramuscular administration, intraarticular administration, oral mucosal administration, vaginal administration, and intranasal administration, etc. Depending on the desired dosage form, those skilled in the art can also select the corresponding pharmaceutically acceptable carrier, diluent, or excipient.

[0083] Disease prevention and treatment methods

[0084] As described above, given that the 3-hydroxy-5-pregnane-20-one derivatives of the present invention can release active allopregnanolone under appropriate conditions after being administered to a recipient, those skilled in the art will appreciate that the 3-hydroxy-5-pregnane-20-one derivatives of the present invention can be used to prevent or treat central nervous system disorders, including but not limited to the aforementioned central nervous system disorders.

[0085] The method of preventing or treating central nervous system disorders of the present invention comprises administering a therapeutically effective amount of the above-mentioned compound or pharmaceutical composition to a subject in need thereof, including but not limited to humans.

[0086] Advantages of the present invention:

[0087] 1. The 3-hydroxy-5-pregnane-20-one derivatives of the present invention have improved solubility;

[0088] 2. The 3-hydroxy-5-pregnane-20-one derivative of the present invention has a certain storage stability in glucose solution;

[0089] 3. The 3-hydroxy-5-pregnane-20-one derivatives of the present invention can be prepared into long-acting sustained-release preparations, and individual differences after administration are small;

[0090] 4. The preparation of the present invention is easy to administer; and

[0091] 5. The preparation of the present invention has high patient compliance when administered.

[0092] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the invention. The experimental methods in the following examples, for which specific conditions are not specified, are generally based on conventional conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0093] The reagents and raw materials used in the present invention are commercially available.

[0094] Example 1. Synthesis of Compound 1 Hydrochloride

[0095]

[0096] Preparation of intermediate 1.2:

[0097] To a 1000 mL three-necked round-bottomed reaction flask, add compound 1.1 (50.0 g, 157.0 mmol, 1.0 eq), Boc-L-Val-OH (40.9 g, 188.2 mmol), DMAP (1.9 g, 15.5 mmol), and 500 mL of dichloromethane. With magnetic stirring, cool the reaction system to -5 to 10°C under nitrogen. Add a solution of DCC (38.9 g, 188.5 mmol) in dichloromethane (80 mL) dropwise. Continue reacting at this temperature for 3 hours. Monitor the reaction by TLC until complete, then stop the reaction. Filter the reaction mixture, and wash the filter cake with dichloromethane (100 mL). The filtrate was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) petroleum ether (60-90) / ethyl acetate 20:1-10:1) to obtain an off-white waxy solid (78.2 g, yield 96.2%).

[0098] Preparation of intermediate 1.3:

[0099] Compound 1.2 (78 g, 150.6 mmol, 1.0 eq) and dichloromethane (320 mL) were added to a 1000 mL three-necked round-bottom reaction flask. Under nitrogen protection and magnetic stirring, the system was cooled to 0-10°C and trifluoroacetic acid (171.8 g, 1510 mmol) was added dropwise rapidly. The reaction was then allowed to react at 15-25°C for 3 hours to stop the reaction. The reaction solution was poured into a sodium bicarbonate (164.5 g, 1958 mmol) solution (780 mL of water) to quench the solution, maintaining the pH at around 8. Dichloromethane (700 mL) was added and the mixture was stirred and separated to obtain the organic phase. The organic phase was then washed with 500 mL of pure water and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (59.5 g, 94.6% yield).

[0100] Preparation of intermediate 1.4:

[0101] To a 250 mL single-necked reaction flask, compound Boc-L-Val-OH (3.4 g, 15.8 mmol) and dichloromethane (60 mL) were added with magnetic stirring. N,N-diisopropylethylamine (2.0 g, 15.8 mmol), TBTU (5.1 g, 15.8 mmol), and compound 1.3 (6.0 g, 14.4 mmol, 1.0 eq) were then added. The reaction was allowed to proceed at room temperature for approximately 1 hour, after which the reaction was terminated. The reaction solution was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) petroleum ether (60-90) / ethyl acetate 50:1-10:1) to afford an off-white solid (7.9 g, 96.2% yield).

[0102] Preparation of intermediate 1.5:

[0103] Compound 1.4 (7.9 g, 12.8 mmol, 1.0 eq) and dichloromethane (32 mL) were added to a 250 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (14.6 g, 128.0 mmol) was added at 0-10°C, followed by reaction at room temperature for 3 hours to stop the reaction. The reaction solution was concentrated under reduced pressure, dichloromethane (70 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (30 mL). The organic phases were combined and washed with 100 mL of pure water. The organic phase was dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (6.5 g, yield 98.2%).

[0104] Preparation of compound 1 hydrochloride:

[0105] To a 250 mL single-necked reaction flask, compound 1.5 (6.5 g, 12.6 mmol, 1.0 eq) and ethyl acetate (32 mL) were added. Under nitrogen protection and magnetic stirring, a solution of hydrogen chloride in ethyl acetate (3 M, 5.0 mL, 15.0 mmol) was added at room temperature and stirred for 1 hour. A white colloid precipitated and the solvent was evaporated to dryness. Isopropanol (60 mL) was added and heated to dissolve. The mixture was then stirred at room temperature for 50 minutes, filtered, and washed with isopropanol (7 mL) to obtain an off-white solid (3.2 g, 46.0% yield).

[0106] 1H NMR (400MHz, CDCl3) δ8.34 (bs, 3H), 7.80-7.59 (m, 1H), 5.21-5.01 (m, 1H), 4.54-4.41 (m, 1H), 4.36-4.20 (m, 1H), 2.53 (t, J=8.8Hz, 1H), 2.45-2.10 (m, 3H), 2.12 (s, 3H), 2.0 5-1.97 (m, 1H), 1.78-0.90 (m, 19H), 1.16 (d, J = 6.9Hz, 3H), 1.11 (d, J = 6.8Hz, 3H), 1.05 (d, J=3.3Hz, 3H), 1.03 (d, J=3.2Hz, 3H), 0.86-0.73 (m, 1H), 0.79 (s, 3H), 0.61 (s, 3H).

[0107] MS: m / z[M+H] + 517.6

[0108] Example 2. Synthesis of Compound 2 Hydrochloride

[0109]

[0110] Preparation of intermediate 2.1:

[0111] To a 250 mL single-necked reaction flask, compound 1.3 (5.0 g, 12.0 mmol), Boc-Gly-OH (2.5 g, 14.3 mmol), and dichloromethane (50 mL) were added and magnetically stirred. N,N-diisopropylethylamine (3.1 g, 24.0 mmol), HOBT (342 mg, 2.4 mmol), and EDCI (2.8 g, 14.6 mmol) were then added. The reaction was allowed to react at room temperature for 4 hours. The reaction solution was washed with H2O (50 mL), 1N HCl (50 mL), saturated aqueous NaHCO3, and purified water. The product was concentrated under reduced pressure and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-3:1) to afford an off-white solid (5.7 g, 82.8% yield).

[0112] Preparation of intermediate 2.2:

[0113] Compound 1.4 (5.5 g, 9.63 mmol, 1.0 eq) and dichloromethane (22 mL) were added to a 250 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (10.9 g, 95.7 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated, dichloromethane (50 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (30 mL). The organic phases were combined, washed with 50 mL of pure water, and dried over anhydrous sodium sulfate. Filtered, concentrated under reduced pressure, and dried under oil pump vacuum to obtain an off-white solid (4.5 g, yield 99.0%).

[0114] Preparation of compound 2 hydrochloride:

[0115] To a 250 mL single-necked reaction flask, add compound 1.5 (4.5 g, 9.5 mmol, 1.0 eq) and ethyl acetate (27 mL). Under nitrogen protection and magnetic stirring, add a 3 M solution of hydrogen chloride in ethyl acetate (3.8 mL, 11.4 mmol) at room temperature and continue stirring for 1 hour. Concentrate under reduced pressure, evaporate the solvent, add acetonitrile (70 mL), and stir at room temperature for 2 hours. Filter, and wash the solid with acetonitrile (15 mL). Dry under oil vacuum at 40°C for 2 hours to obtain a white solid (3.5 g, 72.2% yield).

[0116] 1 H NMR (400MHz, CDCl3) δ8.28 (d, J=8.5Hz, 1H), 8.16 (bs, 3H), 5.14-5.03 (m, 1H) , 4.55 (d, J = 4.1Hz, 1H), 4.27 (d, J = 16.1Hz, 1H), 4.09 (d, J = 16.0Hz, 1H), 2.52 (t, J=8.7Hz, 1H), 2.40-2.07 (m, 2H), 2.11 (s, 3H), 2.05-1.96 (m, 1H), 1.82-1 .08(m, 18H), 1.08-0.89(m, 7H), 0.85-0.71(m, 1H), 0.79(s, 3H), 0.61(s, 3H).

[0117] MS: m / z[M+H] + 475.3.

[0118] Example 3. Synthesis of Compound 3 Hydrochloride

[0119]

[0120] Preparation of intermediate 3.1:

[0121] To a 100 mL single-necked reaction flask was added Boc-LPh-e-OH (0.96 g, 3.6 mmol), dichloromethane (12 mL), N,N-diisopropylethylamine (0.44 g, 3.6 mmol), TBTU (1.16 g, 3.6 mmol), and 1.3 (1.25 g, 3.0 mmol, 1.0 eq). The mixture was stirred magnetically and the reaction continued for 40 minutes. The mixture was concentrated under reduced pressure and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-4:1) to afford a light yellow solid (1.5 g, 75.3% yield).

[0122] Preparation of intermediate 3.2:

[0123] Compound 3.1 (1.5 g, 2.3 mmol, 1.0 eq) and dichloromethane (7.5 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (2.63 g, 23 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated to dryness, dichloromethane (50 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (20 mL). The organic phases were combined, washed with 50 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (1.1 g, yield 86.3%).

[0124] Preparation of compound 3 hydrochloride:

[0125] To a 100 mL single-necked reaction flask, add compound 3.2 (1.1 g, 1.95 mmol, 1.0 eq) and ethyl acetate (11 mL). Under nitrogen protection and magnetic stirring, add a 3 M solution of hydrogen chloride in ethyl acetate (0.8 mL, 2.4 mmol) at room temperature and continue stirring for 1 hour. Concentrate to dryness under reduced pressure and crystallize from ethanol / water (2:1, 15 mL). Filter and dry under oil vacuum at 50°C for 4 hours to obtain a pale yellow solid (620 mg, 52.9% yield).

[0126] 1H NMR (400MHz, CDCl3) δ7.88 (d, J=9.2Hz, 1H), 7.38-7.17 (m, 5H), 5.15-5.05 (m, 1H), 4.57 (dd, J=9.2, 4 .6Hz, 1H), 3.67 (dd, J=9.5, 3.8Hz, 1H), 3.30 (dd, J=13.7, 3.8Hz, 1H), 2.72 (dd, J=13.7, 9.5Hz, 1H), 2. 53(t, J=8.8Hz, 1H), 2.28-2.07(m, 2H), 2.12(s, 3H), 2.05-1.97(m, 1H), 1.78-1.10(m, 18H), 1.00-0. 85 (m, 1H), 0.95 (d, J=6.9Hz, 3H), 0.92 (d, J=6.8Hz, 3H), 0.83-0.72 (m, 1H), 0.80 (s, 3H), 0.61 (s, 3H).

[0127] MS: [M+H] + 565.40.

[0128] Example 4. Synthesis of Compound 4 Hydrochloride

[0129]

[0130] Preparation of intermediate 4.1:

[0131] To a 100 mL single-necked reaction flask, Boc-L-Pro-OH (0.77 g, 3.6 mmol), dichloromethane (12 mL), N,N-diisopropylethylamine (0.44 g, 3.6 mmol), TBTU (1.16 g, 3.6 mmol), and compound 1.3 (1.25 g, 3.0 mmol, 1.0 eq) were added. The mixture was stirred magnetically and then reacted at room temperature for 40 minutes. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-3:1) to afford an off-white solid (1.6 g, 86.9% yield).

[0132] Preparation of intermediate 4.2:

[0133] Compound 4.1 (1.41 g, 2.3 mmol, 1.0 eq) and dichloromethane (7 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (2.63 g, 23 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated to dryness, dichloromethane (50 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (20 mL). The organic phases were combined, washed with 50 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (1.0 g, yield 84.7%).

[0134] Preparation of compound 4 hydrochloride:

[0135] To a 100 mL single-necked reaction flask, add compound 3.2 (1.0 g, 1.94 mmol, 1.0 eq) and ethyl acetate (11 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 0.8 mL, 2.4 mmol) at room temperature. Stirring is continued for 17 hours. A white solid precipitates, which is filtered and washed with ethyl acetate (3 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (560 mg, 52.0% yield).

[0136] 1 H NMR (400MHz, CDCl3) δ11.34 (bs, 1H), 8.01 (d, J=7.7Hz, 1H), 7.69-7.34 (m, 1H), 5.16-5.03 (m, 1H), 5.01-4. 89 (m, 1H), 4.43 (dd, J=7.7, 4.6Hz, 1H), 3.62-3.49 (m, 1H), 3.48-3.37 (m, 1H), 2.72-2.58 (m, 1H), 2.53 (t, J =8.9Hz, 1H), 2.38-2.26(m, 1H), 2.25-2.09(m, 3H), 2.12(s, 3H), 2.07-1.96(m, 2H), 1.88-1.10(m, 18H), 1. 05 (d, J=2.1Hz, 3H), 1.09-0.88 (m, 1H), 1.03 (d, J=2.2Hz, 3H), 0.85-0.72 (m, 1H), 0.80 (s, 3H), 0.61 (s, 3H).

[0137] MS: [M+H] + 515.4.

[0138] Example 5. Synthesis of Compound 5 Hydrochloride

[0139]

[0140] Preparation of intermediate 5.1:

[0141] To a 100 mL single-necked reaction flask, add Boc-L-Trp-OH (1.10 g, 3.6 mmol), dichloromethane (12 mL), N,N-diisopropylethylamine (0.44 g, 3.6 mmol), and TBTU (1.16 g, 3.6 mmol). After stirring at room temperature for 6 minutes, compound 1.3 (1.25 g, 3.0 mmol, 1.0 eq) was added. The mixture was magnetically stirred and the reaction continued at room temperature for 40 minutes. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-3:1) to afford an off-white solid (1.7 g, 80.7% yield).

[0142] Preparation of intermediate 5.2:

[0143] Compound 5.1 (1.58 g, 2.3 mmol, 1.0 eq) and dichloromethane (8 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (2.63 g, 23 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated to dryness, dichloromethane (50 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (20 mL). The organic phases were combined, washed with 50 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (1.20 g, yield 88.5%).

[0144] Preparation of compound 5 hydrochloride:

[0145] To a 100 mL single-necked reaction flask, add compound 3.2 (1.15 g, 1.95 mmol, 1.0 eq) and ethyl acetate (11 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 0.8 mL, 2.4 mmol) at room temperature and continue stirring for 1 hour. Concentrate to dryness under reduced pressure and stir in petroleum ether / ethyl acetate (5:1, 30 mL). Filter and dry under vacuum at 40°C for 3 hours to obtain an off-white solid (690 mg, 56.7% yield).

[0146] 1H NMR (400MHz, CDCl3) δ9.35 (s, 1H), 7.96 (bs, 3H), 7.74-7.41 (m, 2H), 7.38- 7.16(m, 2H), 7.13-6.74(m, 2H), 5.13-4.96(m, 1H), 4.60-4.20(m, 2H), 3.54 -3.20(m,2H),2.35-2.22(m,1H),2.17-1.96(m,2H),2.05(s,3H),1.92-1.8 0 (m, 1H), 1.79-0.99 (m, 18H), 1.00-0.63 (m, 8H), 0.75 (s, 3H), 0.53 (s, 3H).

[0147] MS: [M+H] + 604.4.

[0148] Example 6. Synthesis of Compound 6 Hydrochloride

[0149]

[0150] Preparation of intermediate 6.1:

[0151] To a 250 mL single-necked reaction flask were added compound 1.3 (6.26 g, 15.0 mmol), Boc-L-Ala-OH (3.41 g, 18 mmol), dichloromethane (60 mL), triethylamine (3.04 g, 30 mmol), HOBT (0.41 g, 3 mmol), and EDCI (3.45 g, 18 mmol) with magnetic stirring. The mixture was allowed to react at room temperature for 4 hours. The reaction solution was then washed with H2O (50 mL), 1N HCl (50 mL), and saturated aqueous NaHCO3. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-3:1) to afford an off-white solid (8.20 g, 92.9% yield).

[0152] Preparation of intermediate 6.2:

[0153] Compound 6.1 (7.9 g, 13 mmol, 1.0 eq) and dichloromethane (40 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (14.8 g, 130 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated to dryness, dichloromethane (100 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (50 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered, concentrated under reduced pressure, and dried under oil pump vacuum to obtain an off-white solid (6.25 g, yield 95.3%).

[0154] Preparation of compound 6 hydrochloric acid:

[0155] To a 100 mL single-necked reaction flask, add compound 6.2 (6.0 g, 12.3 mmol, 1.0 eq) and ethyl acetate (60 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 5 mL, 15 mmol) at room temperature. Stirring is continued for 6 hours. A white solid precipitates, which is filtered and washed with ethyl acetate (15 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (4.7 g, 72.9% yield).

[0156] 1 H NMR (400MHz, CDCl3) δ8.33 (bs, 3H), 7.96-7.67 (m, 1H), 5.20-5.00 (m, 1H), 4.76-4.36 (m, 2H), 2.53 (t, J=8.6Hz, 1H), 2.39-2.07(m, 2H), 2.11(s, 3H), 2.05-1.96(m, 1H), 1.80-0.89(m, 28H), 0.88-0.71(m, 1H), 0.79(s, 3H), 0.61(s, 3H).

[0157] MS: [M+H] + 489.4.

[0158] Example 7. Synthesis of Compound 7 Hydrochloride

[0159]

[0160] Preparation of intermediate 7.1:

[0161] To a 250 mL single-necked reaction flask were added compound 1.3 (2.09 g, 5.0 mmol), Boc-L-Leu-OH (1.50 g, 6.0 mmol), dichloromethane (20 mL), triethylamine (0.76 g, 7.5 mmol), HOBT (0.14 g, 1 mmol), and EDCI (1.15 g, 6 mmol). The mixture was stirred magnetically and allowed to react at room temperature for 4 hours. The reaction solution was washed with H2O (50 mL), 1N HCl (50 mL), and saturated aqueous NaHCO3. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-3:1) to afford an off-white solid (3.0 g, 95.0% yield).

[0162] Preparation of intermediate 7.2:

[0163] Compound 7.1 (3.0 g, 4.7 mmol, 1.0 eq) and dichloromethane (12 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (5.42 g, 47 mmol) was added at 0°C, and after 20 minutes, the temperature was raised to room temperature and the reaction was continued for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated, dichloromethane (30 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (10 mL). The organic phases were combined, washed with 30 mL of pure water, and dried over anhydrous sodium sulfate. Filtered, concentrated under reduced pressure, and dried under oil pump vacuum to obtain an off-white solid (1.30 g, yield 51.5%).

[0164] Preparation of compound 7 hydrochloride:

[0165] To a 50 mL single-necked reaction flask, add compound 7.2 (1.30 g, 2.5 mmol, 1.0 eq) and ethyl acetate (13 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 5 mL, 15 mmol) at room temperature. Stirring is continued for 6 hours. A white solid precipitates, which is filtered and washed with ethyl acetate (15 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (0.9 g, 64.8% yield).

[0166] 1 H NMR (400MHz, CDCl3) δ8.40 (s, 3H), 7.55 (d, J=7.9Hz, 1H), 5.17-5.05 (m, 1H), 4.57-4.44 (m, 1H), 4.36-4.21 ( m, 1H), 2.52 (t, J=8.8Hz, 1H), 2.35-1.97 (m, 3H), 2.11 (s, 3H), 1.96-0.73 (m, 35H), 0.80 (s, 3H), 0.61 (s, 3H).

[0167] MS: m / z[M+H] + 531.4.

[0168] Example 8. Synthesis of Compound 8 Hydrochloride

[0169]

[0170] Preparation of intermediate 8.1:

[0171] To a 250 mL three-necked reaction flask were added compound 1.3 (5.00 g, 11.98 mmol, 1.0 eq), Boc-L-Gln-OH (3.54 g, 14.38 mmol), DMAP (0.15 g, 1.20 mmol), and dichloromethane (40 mL). Under nitrogen, with magnetic stirring and cooling in an ice-water bath, a solution of DCC (2.97 g, 14.38 mmol) in dichloromethane (50 mL) was added. After addition, the mixture was allowed to react at room temperature for 3 hours. The reaction solution was washed with 1N HCl (50 mL) and saturated aqueous NaHCO₃. Drying was performed over anhydrous Na₂SO₄, and filtering was performed. The residue was concentrated under reduced pressure and dried under an oil pump vacuum to afford a white solid (4.42 g, 57.2% yield).

[0172] Preparation of intermediate 8.2:

[0173] Compound 8.1 (4.42 g, 6.84 mmol, 1.0 eq) and dichloromethane (22 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (7.80 g, 68.43 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, dichloromethane (100 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (50 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (3.0 g, yield 80.3%).

[0174] Preparation of compound 8 hydrochloride:

[0175] To a 50 mL single-necked reaction flask, add compound 8.2 (1.10 g, 2.02 mmol, 1.0 eq) and dichloromethane (12 mL). Under nitrogen protection and magnetic stirring, add a 3 M solution of hydrogen chloride in ethyl acetate (0.8 mL, 2.4 mmol) at room temperature and continue stirring for 1 hour. Concentrate under reduced pressure to remove the dichloromethane, then add methyl tert-butyl ether / isopropanol (4:1, 20 mL) and stir for 2 hours. Filter and wash with pre-cooled methyl tert-butyl ether / isopropanol (4:1, 5 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (0.85 g, 72.4% yield).

[0176] 1H NMR (400MHz, CDCl3) δ8.67-8.59 (m, 1H), 8.36 (bs, 3H), 7.63 (bs, 1H), 6.92 (bs, 1H), 5.30-4.96 (m, 1H), 4.80-4. 31(m, 2H), 2.80-1.94(m, 6H), 2.52(t, J=8.8Hz, 1H), 2.11(s, 3H), 1.89-0.70(m, 27H), 0.79(s, 3H), 0.60(s, 3H).

[0177] MS: m / z[M+H] + 546.4.

[0178] Example 9. Synthesis of Compound 9 Hydrochloride

[0179]

[0180] Preparation of intermediate 9.1:

[0181] To a 250 mL three-necked reaction flask were added compound 1.3 (9.60 g, 23.1 mmol, 1.0 eq), Boc-Lys(Boc)-OH (8.00 g, 23.1 mmol), DMAP (0.28 g, 2.3 mmol), and dichloromethane (100 mL). Under nitrogen protection, magnetic stirring, and ice-water cooling, a solution of DCC (5.20 g, 25.4 mmol) in dichloromethane (20 mL) was added dropwise to maintain the internal temperature at 3-5°C. The mixture was allowed to react at room temperature for 17 hours. The residue was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-3:1) to afford a white foamy solid (10.0 g, 61.0% yield).

[0182] Preparation of intermediate 9.2:

[0183] Compound 9.1 (10.5 g, 14.1 mmol, 1.0 eq) and dichloromethane (50 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection, magnetic stirring, trifluoroacetic acid (16.0 g, 141.0 mmol) was added at 0°C, and then reacted at room temperature for 3 hours. The reaction solution was added dropwise to a H2O solution of NaHCO3 (28 g) (100 mL) with stirring, and dichloromethane (150 mL) was added. The liquid was separated, and the aqueous phase was extracted with dichloromethane (100 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain a light yellow foamy solid (7.1 g, yield 92%).

[0184] Preparation of compound 9 hydrochloride:

[0185] To a 50 mL single-necked reaction flask, add compound 9.2 (7.0 g, 12.8 mmol, 1.0 eq) and ethyl acetate (20 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 5.1 mL, 15.3 mmol) at room temperature and continue stirring for 1 hour. Concentrate under reduced pressure to remove the ethyl acetate, add methyl tert-butyl ether (100 mL) and stir for 2 hours. Filter and wash with methyl tert-butyl ether (20 mL). Dry under oil vacuum at 45°C for 3 hours to obtain a white solid (7.2 g, 90.7% yield).

[0186] 1 H NMR (400MHz, CDCl3) δ8.30 (bs, 3H), 8.13-7.98 (m, 1H), 7.89 (bs, 3H), 5.20-4.96 (m, 1H), 4.60-4.19 (m, 2 H), 3.17-2.85 (m, 2H), 2.51 (t, J=9.1Hz, 1H), 2.46-0.70 (m, 35H), 2.11 (s, 3H), 0.79 (s, 3H), 0.61 (s, 3H).

[0187] MS: m / z[M+H] + 546.8.

[0188] Example 10. Synthesis of Compound 10 Hydrochloride

[0189]

[0190] Preparation of intermediate 10.1:

[0191] To a 1000 mL three-necked reaction flask were added compound 1.1 (20.0 g, 62.8 mmol, 1.0 eq), Boc-L-Ala-OH (14.3 g, 75.4 mmol), DMAP (0.8 g, 6.3 mmol), and 150 mL of dichloromethane. Under nitrogen protection and magnetic stirring, a solution of DCC (15.5 g, 75.4 mmol) in dichloromethane (50 mL) was added at 0°C and allowed to react at room temperature for 6 hours. The mixture was filtered, and the filter cake was washed with dichloromethane (100 mL). The filtrate was concentrated, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-4:1) to afford a white solid (27.3 g, 88.7% yield).

[0192] Preparation of intermediate 10.2:

[0193] Compound 10.1 (27.0 g, 55.1 mmol, 1.0 eq) and dichloromethane (135 mL) were added to a 500 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (62.8 g, 551 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated, dichloromethane (300 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was washed with dichloromethane (150 mL), and the combined organic phases were washed with 300 mL of pure water and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (20.9 g, 97.3% yield).

[0194] Preparation of intermediate 10.3:

[0195] To a 100 mL single-necked reaction flask were added compound 10.2 (5.0 g, 12.8 mmol), Boc-L-Val-OH (3.3 g, 15.4 mmol), dichloromethane (50 mL), triethylamine (1.6 g, 15.4 mmol), HOBT (0.7 g, 5.1 mmol), and EDCI (3.0 g, 15.4 mmol) with magnetic stirring. The mixture was allowed to react at room temperature for 4 hours. The reaction solution was then washed with H2O (50 mL), 1N HCl (50 mL), and saturated aqueous NaHCO3. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-5:1) to afford a white solid (7.2 g, 95.6% yield).

[0196] Preparation of intermediate 10.4:

[0197] Compound 10.3 (6.0 g, 10.2 mmol, 1.0 eq) and dichloromethane (30 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (11.6 g, 102 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, dichloromethane (100 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (50 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (4.6 g, yield 92.3%).

[0198] Preparation of compound 10 hydrochloride:

[0199] To a 250 mL single-necked reaction flask, add compound 10.3 (4.6 g, 9.4 mmol, 1.0 eq) and ethyl acetate (50 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 3.8 mL, 11.4 mmol) at room temperature. Stirring is continued for 1 hour. A white solid precipitates, which is filtered and washed with ethyl acetate (20 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (4.5 g, 86.4% yield).

[0200] 1 H NMR (400MHz, CDCl3) δ8.28 (bs, 3H), 8.11 (d, J = 6.2Hz, 1H), 5.06 (d, J = 3.4Hz, 1H), 4.51 (p, J=7.0Hz, 1H), 4.23 (d, J=5.6Hz, 1H), 2.53 (t, J=8.8Hz, 1H), 2.4 0 (q, J=6.6Hz, 1H), 2.12 (s, 3H), 2.25-2.09 (m, 2H), 2.08-1.06 (m, 18H), 1.54 -1.50(m,3H),1.22-1.12(m,6H)1.05-0.73(m,2H),0.79(s,3H),0.61(s,3H).

[0201] MS: m / z[M+H] + 489.4.

[0202] Example 11. Synthesis of Compound 11 Hydrochloride

[0203]

[0204] Preparation of intermediate 11.1:

[0205] To a 250 mL single-necked reaction flask were added compound 10.1 (5.0 g, 12.8 mmol), Boc-L-Ala-OH (2.9 g, 15.4 mmol), dichloromethane (50 mL), triethylamine (1.6 g, 15.4 mmol), HOBT (0.7 g, 5.1 mmol), and EDCI (3.0 g, 15.4 mmol) with magnetic stirring. The mixture was allowed to react at room temperature for 4 hours. The reaction solution was then washed with H2O (50 mL), 1N HCl (50 mL), and saturated aqueous NaHCO3. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-3:1) to afford a white solid (6.7 g, 93.5% yield).

[0206] Preparation of intermediate 11.2:

[0207] Compound 11.1 (5.8 g, 10.3 mmol, 1.0 eq) and dichloromethane (30 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (11.8 g, 103 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, dichloromethane (100 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (50 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (4.5 g, yield 94.4%).

[0208] Preparation of compound 11 hydrochloride:

[0209] To a 250 mL single-necked reaction flask, add compound 11.2 (4.5 g, 9.8 mmol, 1.0 eq) and ethyl acetate (50 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 3.9 mL, 11.7 mmol) at room temperature. Stirring is continued for 1 hour. A white solid precipitates, which is filtered and washed with ethyl acetate (20 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (4.2 g, 86.5% yield).

[0210] 1 H NMR (400MHz, CDCl3) δ8.14 (m, 4H), 5.05 (m, 1H), 4.47 (dt, J=21.0, 6.9Hz, 1H), 2.53 (t, J=8.8Hz, 1H), 2.12 (s, 3H), 2.24 -1.97(m, 2H), 1.94-1.07(m, 19H), 1.69-1.65(m, 3H), 1.52-1.47(m, 3H), 0.79(s, 3H), 1.05-0.73(m, 2H), 0.61(s, 3H).

[0211] MS: m / z[M+H] + 461.3.

[0212] Example 12. Synthesis of Compound 12 Hydrochloride

[0213]

[0214] Preparation of intermediate 12.1:

[0215] To a 250 mL single-necked reaction flask were added compound 10.1 (5.0 g, 12.8 mmol), Boc-Gly-OH (2.7 g, 15.4 mmol), dichloromethane (50 mL), triethylamine (1.6 g, 15.4 mmol), HOBT (0.7 g, 5.1 mmol), and EDCI (3.0 g, 15.4 mmol). The mixture was allowed to react at room temperature for 4 hours. The reaction solution was washed with H2O (50 mL), 1N HCl (50 mL), and saturated aqueous NaHCO3. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-3:1) to afford a white solid (6.5 g, 93.1% yield).

[0216] Preparation of intermediate 12.2:

[0217] Compound 11.1 (5.8 g, 10.6 mmol, 1.0 eq) and dichloromethane (30 mL) were added to a 100 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (12.1 g, 106 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, dichloromethane (100 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (50 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain a white solid (4.5 g, yield 95.0%).

[0218] Preparation of compound 12 hydrochloride:

[0219] To a 250 mL single-necked reaction flask, add compound 11.2 (4.5 g, 10.1 mmol, 1.0 eq) and ethyl acetate (50 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 4.0 mL, 12.0 mmol) at room temperature. Stirring is continued for 1 hour. A white solid precipitates, which is filtered and washed with ethyl acetate (20 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (4.6 g, 94.5% yield).

[0220] 1 H NMR (400MHz, CDCl3) δ8.49 (d, J=7.2Hz, 1H), 8.08 (bs, 3H), 5.06 (m, 1H), 4.55 (p, J=7.1Hz, 1H), 4.35-3.94 (m, 2H), 2.51 (t, J=8 .7Hz, 1H), 2.11 (s, 3H), 2.17-1.95 (m, 2H) 1.94-0.88 (m, 19H), 1.51-1.45 (m, 3H), 0.87-0.72 (m, 1H), 0.79 (s, 3H), 0.61 (s, 3H).

[0221] MS: m / z[M+H] + 447.3.

[0222] Example 13. Synthesis of Compound 13 Hydrochloride

[0223]

[0224] Preparation of intermediate 13.2:

[0225] To a 500 mL three-necked reaction flask were added compound 13.1 (10.0 g, 55.5 mmol, 1.0 eq), Boc-L-Val-OH (12.0 g, 55.5 mmol), DMAP (1.4 g, 11.5 mmol), and 100 mL of dichloromethane. Under nitrogen protection and magnetic stirring, a solution of DCC (13.7 g, 66.6 mmol) in dichloromethane (50 mL) was added at 0°C, followed by reaction at room temperature for 6 hours. The mixture was filtered, and the filter cake was washed with dichloromethane (100 mL). The filtrate was concentrated, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 20:1-6:1) to afford a colorless oil (20.5 g, 97.3% yield).

[0226] Preparation of intermediate 13.3:

[0227] To a 1000 mL single-necked reaction flask, compound 13.2 (20.0 g, 52.7 mmol) and THF (300 mL) were added. After nitrogen substitution, 10% Pd / C (2 g) was added. After hydrogen substitution, the reaction mixture was hydrogenated at room temperature under normal pressure for 6 hours. After nitrogen substitution, the mixture was filtered and washed with THF (50 mL). The filtrate was concentrated, the solvent evaporated, and dried under oil vacuum at room temperature to afford a white solid (14.9 g, 97.7% yield).

[0228] Preparation of intermediate 13.4:

[0229] To a 250 mL three-necked reaction flask were added compound 1.1 (5.0 g, 15.7 mmol, 1.0 eq), compound 13.3 (5.4 g, 18.7 mmol), DMAP (0.2 g, 1.6 mmol), and 50 mL of dichloromethane. Under nitrogen protection and magnetic stirring, a solution of DCC (3.9 g, 18.9 mmol) in dichloromethane (15 mL) was added at 0°C and allowed to react at room temperature for 2 hours. The mixture was filtered, and the filter cake was washed with dichloromethane (20 mL). The filtrate was concentrated, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 20:1-3:1) to afford a white solid (8.7 g, 93.9% yield).

[0230] Preparation of intermediate 13.5:

[0231] Compound 13.4 (8.0 g, 13.6 mmol, 1.0 eq) and dichloromethane (40 mL) were added to a 250 mL three-necked reaction flask. Trifluoroacetic acid (15.5 g, 136 mmol) was added under nitrogen at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, and dichloromethane (150 mL) was added. The mixture was washed with saturated sodium bicarbonate aqueous solution, and the aqueous phase was extracted with dichloromethane (50 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain a white solid (6.5 g, yield 97.8%).

[0232] Preparation of compound 13 hydrochloride:

[0233] To a 250 mL single-necked reaction flask, add compound 13.4 (6.0 g, 12.3 mmol, 1.0 eq) and ethyl acetate (60 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride in ethyl acetate (3 M, 4.9 mL, 14.7 mmol) at room temperature and continue stirring for 1 hour. A white solid precipitated, which was filtered and washed with ethyl acetate (20 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (5.2 g, 80.6% yield).

[0234] 1 H NMR (400MHz, CDCl3) δ8.76 (s, 3H), 5.25 (q, J=7.0Hz, 1H), 5.08 (q, J=2.8Hz, 1H), 4.02 (d, J=3.9Hz, 1H ), 2.62-2.45(m, 2H), 2.12(s, 3H), 2.01(dt, J=11.9, 3.3Hz, 1H), 1.78-1.63(m, 5H), 1.63-1.58(m, 1H ), 1.56 (d, J=7.1Hz, 4H), 1.50 (t, J=5.1Hz, 3H), 1.45-1.32 (m, 3H), 1.28 (dd, J=13.2, 3.9Hz, 2H), 1.2 2 (dd, J=7.0, 2.7Hz, 7H), 1.20-1.09 (m, 4H), 0.96 (dd, J=12.3, 4.6Hz, 1H), 0.79 (s, 3H), 0.61 (s, 3H).

[0235] MS: m / z[M+H] + 490.3.

[0236] Example 14. Synthesis of Compound 14 Hydrochloride

[0237]

[0238] Preparation of intermediate 14.1:

[0239] To a 1000 mL three-necked reaction flask were added compound 1.1 (50.0 g, 157.0 mmol, 1.0 eq), Boc-Gly-OH (33.0 g, 188.2 mmol), DMAP (1.9 g, 15.5 mmol), and 500 mL of dichloromethane. Under nitrogen protection and magnetic stirring, a solution of DCC (38.9 g, 188.5 mmol) in dichloromethane (80 mL) was added at 0°C. The mixture was then allowed to react at room temperature for 2 hours before being stopped. The mixture was filtered, and the filter cake was washed with dichloromethane (100 mL). The filtrate was concentrated, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 20:1-4:1) to afford a white solid (71.8 g, 95.8% yield).

[0240] Preparation of intermediate 14.2:

[0241] Compound 1.2 (30 g, 63.1 mmol, 1.0 eq) and dichloromethane (1200 mL) were added to a 1000 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (71.9 g, 631 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated, dichloromethane (500 mL) and isopropanol (50 mL) were added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The organic phase was washed with 500 mL of pure water and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (21.7 g, 91.6% yield).

[0242] Preparation of intermediate 14.3:

[0243] To a 250 mL single-necked reaction flask were added Boc-L-Val-OH (3.4 g, 15.8 mmol), dichloromethane (60 mL), N,N-diisopropylethylamine (2.0 g, 15.8 mmol), TBTU (5.1 g, 15.8 mmol), and compound 14.2 (5.4 g, 14.4 mmol, 1.0 eq). The mixture was reacted at room temperature for 40 minutes. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 20:1-5:1) to afford an off-white solid (7.8 g, 92.6% yield).

[0244] Preparation of intermediate 14.4:

[0245] Compound 1.4 (7.8 g, 13.6 mmol, 1.0 eq) and dichloromethane (32 mL) were added to a 250 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (15.5 g, 135.9 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, the solvent was evaporated to dryness, dichloromethane (100 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The aqueous phase was extracted with dichloromethane (50 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain an off-white solid (6.2 g, 96.2% yield).

[0246] Preparation of compound 14 hydrochloride:

[0247] To a 250 mL single-necked reaction flask, add compound 1.5 (6.0 g, 12.6 mmol, 1.0 eq) and ethyl acetate (42 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 5.0 mL, 15.0 mmol) and methyl tert-butyl ether (42 mL) at room temperature. Stir at room temperature for 50 minutes and then at 0°C for 1 hour. Filter and wash with pre-chilled ethyl acetate (10 mL) to obtain an off-white solid (5.3 g, 82.0% yield).

[0248] 1 H NMR (400MHz, CDCl3) δ8.54 (s, 1H), 8.38-8.02 (s, 3H), 5.18-4.96 (m, 1H), 4.33 (d, J=5. 3Hz, 1H), 4.07 (s, 2H), 2.52 (t, J=8.9Hz, 1H), 2.43 (q, J=6.5Hz, 1H), 2.12 (s, 3H), 2.02 (dd, J=12.3, 3.4Hz, 1H), 1.82-1.56 (m, 6H), 1.56-1.32 (m, 6H), 1.32-1.20 (m, 4H), 1.1 6 (d, J=6.8Hz, 6H), 1.12 (d, J=6.7Hz, 3H), 1.03-0.81 (m, 2H), 0.79 (s, 3H), 0.61 (s, 3H).

[0249] MS: m / z[M+H] + 475.3.

[0250] Example 15. Synthesis of Compound 15 Hydrochloride

[0251]

[0252] Preparation of intermediate 15.1:

[0253] To a 250 mL single-necked reaction flask were added compound 14.2 (5.0 g, 13.3 mmol), Boc-Gly-OH (2.8 g, 16.0 mmol), dichloromethane (50 mL), triethylamine (1.6 g, 16.0 mmol), HOBt (0.7 g, 5.1 mmol), and EDCI (3.1 g, 16.2 mmol). The mixture was allowed to react at room temperature for 4 hours. The reaction solution was washed with H2O (50 mL), 1N HCl (50 mL), and saturated aqueous NaHCO3. The mixture was concentrated under reduced pressure, and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-2:1) to afford a white solid (6.2 g, 87.4% yield).

[0254] Preparation of intermediate 15.2:

[0255] Compound 15.1 (3.0 g, 5.6 mmol, 1.0 eq) and dichloromethane (15 mL) were added to a 250 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (6.4 g, 56 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, and dichloromethane (100 mL) was added. The mixture was washed with 100 mL of saturated sodium bicarbonate aqueous solution, and the aqueous phase was extracted with dichloromethane (50 mL). The organic phases were combined, washed with 100 mL of pure water, and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain a white solid (2.0 g, yield 82.1%).

[0256] Preparation of compound 15 hydrochloride:

[0257] To a 250 mL single-necked reaction flask, add compound 15.2 (2.0 g, 4.6 mmol, 1.0 eq) and ethyl acetate (20 mL). Under nitrogen protection and magnetic stirring, add hydrogen chloride ethyl acetate solution (3 M, 1.9 mL, 5.7 mmol) at room temperature and continue stirring for 1 hour. A white solid precipitates and is filtered. The solid is dissolved in MeCN / H2O (23 mL) by heating under reflux, stirring at room temperature for 1 hour and then at 0°C for 1 hour. Filter and wash with MeCN (5 mL). Dry under oil vacuum at 40°C for 3 hours to obtain a white solid (1.2 g, 55.3% yield).

[0258] 1 H NMR (400MHz, CD3OD) δ5.10-5.02 (m, 1H), 4.03 (s, 2H), 3.74 (s, 2H), 2.63 (t, J=9.0Hz, 1H), 2.17-2.00 (m , 2H), 2.11(s, 3H), 1.85-1.10(m, 18H), 1.07-0.90(m, 1H), 0.88-0.77(m, 1H), 0.85(s, 3H), 0.61(s, 3H).

[0259] MS: m / z[M+H] + 433.5.

[0260] Example 16. Synthesis of Compound 16 Hydrochloride

[0261]

[0262] Preparation of intermediate 16.1

[0263] To a 100 mL reaction flask, L-OH-IIe-Boc (2.00 g, 8.63 mmol, 1.2 eq), EDCI (1.65 g, 8.63 mmol, 1.2 eq), HOBt (0.2 g, 1.40 mmol, 1.2 eq) and N, N-diisopropylethylamine (1.86 g, 14.38 mmol, 2.0 eq) were added in sequence to a 100 mL eggplant-shaped flask, and dichloromethane (25 mL) was added, and the mixture was stirred under ice bath until homogeneous; then 1.3 (3.00 g, 7.19 mmol, 1.0 eq) was slowly added to the reaction solution, stirred under ice bath for 1 hour, moved to room temperature and stirred for 3 hours, and the reaction was determined to be complete by TLC detection. The reaction mixture was adjusted to neutral with 1.0 M hydrochloric acid, separated, and the organic phase was washed with saturated NaHCO 3 , combined, and dried over anhydrous sodium sulfate for 2.0 hours; the solvent was evaporated to give a colorless gum (4.12 g, yield 90.95%).

[0264] Preparation of intermediate 16.2:

[0265] To a 100 mL reaction flask, add 16.1 (4.12 g, 6.53 mmol, 1.0 eq) and dichloromethane (40 mL) and stir until homogeneous. Add trifluoroacetic acid (12 mL), and the reaction solution gradually turns light yellow. Stir at room temperature for 1 hour. The reaction is complete as determined by TLC. Evaporate the solvent to obtain a colorless oil, which is dissolved in dichloromethane and the pH of the solution is adjusted to approximately 8 with saturated NaHCO3. Separate the layers and take the organic phase, drying it over anhydrous sodium sulfate. Evaporate the solvent to obtain a colorless oil (3.15 g, 90.78% yield).

[0266] Preparation of compound 16 hydrochloride:

[0267] To a 50 mL reaction flask, add 16.2 (3.15 g, 5.94 mmol, 1.0 eq) and ethyl acetate (50 mL) and stir until homogeneous. Add hydrogen chloride / ethyl acetate solution to adjust the pH of the reaction solution to approximately 3-4. With the addition of HCl / ethyl acetate, a white solid gradually precipitates from the reaction solution. Stir at room temperature for 1.0 hour to allow crystallization. Filter to obtain a white solid (1.82 g, 54.17% yield).

[0268] 1H NMR (400MHz, CDCl3) δ8.39 (s, 3H), 7.40 (d, J=7.6Hz, 1H), 5.10 (s, 1H), 4.48 (t, J=6.1Hz, 1H), 4.25 (s , 1H), 2.53 (t, J=8.8Hz, 1H), 2.27 (d, J=6.0Hz, 1H), 2.12 (s, 3H), 2.01 (d, J=118Hz, 1H), 1.81 (s, 5H), 1 .69 (d, J=11.6Hz, 6H), 1.49 (s, 2H), 1.41 (d, J=10.3Hz, 3H), 1.31-1.24 (m, 1H), 1.24-1.20 (m, 3H), 1. 19 (s, 3H), 1.07 (d, J = 6.8Hz, 3H), 1.06-1.00 (m, 6H), 0.98 (t, J = 7.2Hz, 3H), 0.80 (s, 4H), 0.61 (s, 3H).

[0269] MS: m / z[M+H] + 531.39.

[0270] Example 17. Synthesis of Compound 17 Hydrochloride

[0271]

[0272] Preparation of intermediate 17.1

[0273] To a 100 mL reaction flask, 1.3 (3.00 g, 7.19 mmol, 1.0 eq), L-HO-Met-Boc (2.15 g, 8.63 mmol, 1.2 eq), DMAP (0.10 g, 0.72 mmol, 0.1 eq), and 20 mL of dichloromethane were added and stirred under ice until homogeneous. DCC (1.78 g, 8.63 mmol, 1.2 eq) was dissolved in 10 mL of dichloromethane and added to the reaction mixture, followed by stirring at room temperature for 3 hours. TLC confirmed the reaction was complete. The white solid DCU was filtered off, and the organic phase was washed with saturated NaHCO₃. The combined organic phases were dried over anhydrous sodium sulfate, and the solvent was evaporated to obtain a white solid mass. Purification on a silica gel column (petroleum ether (60-90) / ethyl acetate = 10:1) afforded a white solid (3.4 g, 72.96% yield).

[0274] Preparation of intermediate 17.2:

[0275] To a 100 mL reaction flask, add 17.1 (3.4 g, 4.32 mmol, 1.0 eq) and dichloromethane (30 mL) and stir until homogeneous. Add trifluoroacetic acid (9 mL), and the reaction solution gradually turns light yellow. Stir at room temperature for 1 hour. The reaction is complete as determined by TLC. Evaporate the solvent to obtain a colorless oil, which is dissolved in 10 mL of dichloromethane and the pH of the solution is adjusted to approximately 8 with saturated NaHCO3. Separate the layers, combine the organic phases, dry over anhydrous sodium sulfate, and evaporate the solvent to obtain a colorless oil (1.82 g, 63.41% yield).

[0276] Preparation of compound 17 hydrochloride:

[0277] To a 25 mL reaction flask was added 17.2 (1.82 g, 3.33 mmol, 1.0 eq) and dichloromethane (5 mL), stirred until homogeneous, and hydrogen chloride ethyl acetate solution was added to adjust the pH of the reaction solution to about 3-4. The solvent was evaporated to obtain a colorless oily liquid. Ethyl acetate (10 mL) was added and stirred and slurried. The reaction solution gradually became a white suspension. Slurry was added for 3 hours and filtered to obtain a white solid (1.2 g, yield 61.86%).

[0278] 1 H NMR (400MHz, CDCl3) δ8.56 (s, 3H), 7.62 (s, 1H), 5.10 (s, 1H), 4.53 (s, 2H), 2.77 (s, 2H), 2.53 (t, J=8.8 Hz, 1H), 2.42 (s, 1H), 2.16 (s, 3H), 2.12 (s, 3H), 2.01 (d, J = 11.9Hz, 2H), 1.79 (s, 1H), 1.69 (d, J = 11.9Hz , 4H), 1.66-1.58 (m, 2H), 1.54 (d, J=13.3Hz, 2H), 1.49 (s, 3H), 1.41 (t, J=13.0Hz, 2H), 1.28 (d, J=12.9 Hz, 4H), 1.19 (d, J=1.0Hz, 3H), 1.05 (d, J=6.8Hz, 3H), 1.01 (d, J=6.6Hz, 3H), 0.80 (s, 4H), 0.61 (s, 3H).

[0279] MS: m / z[M+H] + 549.4.

[0280] Example 18. Synthesis of Compound 18 Hydrochloride

[0281]

[0282] Preparation of Intermediate 18.1:

[0283] To a 100 mL reaction flask, 1.3 (3.00 g, 7.19 mmol, 1.0 eq), L-HO-Glu-Boc-5-OBn (2.91 g, 8.63 mmol, 1.2 eq), DMAP (0.10 g, 0.72 mmol, 0.1 eq), and 20 mL of dichloromethane were added and stirred under ice until homogeneous. DCC (1.78 g, 8.63 mmol, 1.2 eq) was dissolved in 10 mL of dichloromethane and added to the reaction mixture. The mixture was stirred at room temperature for 3 hours. The reaction was complete as determined by TLC. The white solid DCU was filtered off, and the filtrate was washed with saturated NaHCO₃. The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate = 10:1) to afford a white solid (4.7 g, 88.85% yield).

[0284] Preparation of intermediate 18.2:

[0285] Prepare a hydrogenation kettle equipped with magnetic stirring. Add 18.1 (4.7 g, 6.38 mmol, 1.0 eq) and isopropanol (40 mL) to the reaction flask. Add Pd / C (10%) and replace the hydrogen atmosphere three times. React under approximately 1 MPa of hydrogen pressure and stir at room temperature for 8 hours. TLC confirms the reaction is complete. Evaporate the solvent to obtain a colorless oil, which is dissolved in dichloromethane, washed with water, and the organic phases are combined and dried over anhydrous sodium sulfate. Evaporate the solvent to obtain a white solid (3.12 g, 75.54% yield).

[0286] Preparation of intermediate 18.3:

[0287] To a 100 mL reaction flask, 18.2 (3.0 g, 4.64 mmol, 1.0 eq) and dichloromethane (30 mL) were added and stirred until homogeneous. Trifluoroacetic acid (9 mL) was added, and the reaction solution gradually turned light yellow. Stirring was performed at room temperature for 1 hour. The reaction was complete as determined by TLC. The solvent was evaporated to obtain a colorless oil, which was dissolved in dichloromethane. The pH of the solution was adjusted to approximately 8 with saturated NaHCO₃. The layers were separated, and the organic phase was collected and dried over anhydrous sodium sulfate. The solvent was evaporated to obtain a colorless oil (1.82 g, 71.65% yield).

[0288] Preparation of compound 18 hydrochloride:

[0289] To a 25 mL reaction flask, intermediate 3 (1.82 g, 3.33 mmol, 1.0 eq) and dichloromethane (5 mL) were added and stirred until homogeneous. HCl / ethyl acetate was added to adjust the pH of the reaction solution to about 3-4 and stirred for 10 minutes. The solvent was evaporated to obtain a colorless oily liquid. Ethyl acetate (20 mL) was added and stirring did not completely clarify it. Methyl tert-butyl ether (20 mL) was added and the reaction solution gradually became a white suspension. The mixture was stirred for 3 hours and filtered to obtain a white solid (1.33 g, yield 68.56%).

[0290] 1 H NMR (400MHz, CDCl3) δ8.39-8.23 (d, J=7.8Hz, 1H), 8.21-8.08 (s, 3H), 5.14-5.04 (s, 1H), 4.77-4.60 (s, 1H), 4.52- 4.39 (dd, J=8.0, 4.5Hz, 1H), 2.84-2.64 (s, 2H), 2.58-2.47 (t, J=8.8Hz, 1H), 2.44-2.33 (s, 1H), 2.33-2.21 (dd, J=1 1.9, 6.0Hz, 2H), 2.12-2.07 (s, 3H), 2.04-1.96 (d, J=11.1Hz, 1H), 1.81-1.56 (t, J=15.4Hz, 7H), 1.56-1.32 (m, 7H), 1.31-1.07 (m, 6H), 1.05-1.00 (d, J=3.0Hz, 3H), 1.00-0.93 (d, J=4.7Hz, 4H), 0.82-0.75 (s, 4H), 0.65-0.55 (s, 3H).

[0291] MS: m / z[M+H] + 546.4.

[0292] Example 19. Synthesis of Compound 19 Hydrochloride

[0293]

[0294] Preparation of Intermediate 19.1:

[0295] To a 100 mL reaction flask, L-HO-His-Boc (2.20 g, 8.63 mmol, 1.2 eq), EDCI (1.65 g, 8.63 mmol, 1.2 eq), HOBt (0.2 g, 1.40 mmol, 1.2 eq), N,N-diisopropylethylamine (1.86 g, 14.38 mmol, 2.0 eq) and dichloromethane (3 mL) were added and stirred under ice bath until homogeneous. 1.3 (3.00 g, 7.19 mmol, 1.0 eq) was then slowly added to the reaction solution, stirred under ice bath for 1 hour, moved to room temperature and stirred for 3 hours. The reaction was confirmed to be complete by TLC. The reaction solution was adjusted to neutrality with 1.0 M hydrochloric acid, separated, and the organic phase was washed with saturated NaHCO3, dried over anhydrous sodium sulfate, and the solvent was evaporated to obtain a light yellow oil (3.81 g, yield 96.38%).

[0296] Preparation of intermediate 19.2:

[0297] To a 100 mL reaction flask were added 19.1 (3.81 g, 6.92 mmol, 1.0 eq), dichloromethane (60 mL), and trifluoroacetic acid (20 mL). The reaction solution gradually turned dark yellow and was stirred at room temperature for 1 hour. The reaction was complete as determined by TLC. The solvent was evaporated to obtain a colorless oil, which was dissolved in dichloromethane and the pH of the solution was adjusted to approximately 8 with saturated NaHCO₃. The organic phase was separated and dried over anhydrous sodium sulfate. The solvent was evaporated to obtain a colorless oil (3.09 g, 95.96% yield).

[0298] Preparation of compound 19 hydrochloride:

[0299] To a 50 mL reaction flask, 19.2 (3.09 g, 5.57 mmol, 1.0 eq) and ethyl acetate (20 mL) were added and stirred to dissolve. Hydrogen chloride ethyl acetate solution was added to adjust the pH of the reaction solution to about 3-4. A white solid gradually precipitated from the reaction solution. The mixture was stirred and crystallized for 4 hours and filtered to give a white solid (2.11 g, yield 64.33%).

[0300] 1 H NMR (400MHz, CDCl3) δ13.88 (s, 1H), 8.88 (s, 1H), 8.58 (s, 3H), 7.56 (d, J = 24.9Hz, 1H), 5.11 (s, 1H), 4.98 (s, 1H), 4.50 (s, 1H), 3.57 (s, 2H) , 2.51(s, 2H), 2.11(s, 3H), 2.00(s, 1H), 1.66(s, 6H), 1.50(s, 4H), 1. 39(s, 2H), 1.32-1.11(m, 7H), 1.04(s, 7H), 0.79(s, 4H), 0.60(s, 3H).

[0301] MS: m / z[M+H] + 555.4.

[0302] Example 20. Synthesis of Compound 20 Hydrochloride

[0303]

[0304] Preparation of intermediate 20.1:

[0305] To a 100 mL reaction flask, 1.3 (3.00 g, 7.19 mmol, 1.0 eq), L-HO-Tyr-Boc-O-Boc (2.74 g, 8.63 mmol, 1.2 eq), DMAP (0.10 g, 0.72 mmol, 0.1 eq), and 20 mL of dichloromethane were added and stirred under ice until homogeneous. DCC (1.78 g, 8.63 mmol, 1.2 eq) was dissolved in 10 mL of dichloromethane and added to the reaction mixture, followed by stirring at room temperature for 3 hours. TLC confirmed the reaction was complete. The white solid was filtered off, and the organic phase was washed with saturated NaHCO₃. The combined organic phases were dried over anhydrous sodium sulfate and the solvent was evaporated to obtain a white solid mass. Purification on a silica gel column (petroleum ether (60-90) / ethyl acetate = 10:1 to 5:1) afforded a white solid (0.6 g, yield 10.69%).

[0306] Preparation of intermediate 20.2:

[0307] To a 25 mL reaction flask, add 20.1 (0.60 g, 0.77 mmol, 1.0 eq) and dichloromethane (6.0 mL). Stir until homogeneous. Add trifluoroacetic acid (2.0 mL) and stir at room temperature for 1 hour. The reaction is complete as determined by TLC. Evaporate the solvent to obtain a colorless oil, which is dissolved in dichloromethane and washed with saturated aqueous NaHCO3 solution. The aqueous phase has a pH of 7-8. Separate the liquids and dry the organic phase over anhydrous sodium sulfate. Evaporate the solvent to obtain a colorless oil (0.43 g, 95.56% yield).

[0308] Preparation of compound 20 hydrochloride:

[0309] To a 25 mL reaction flask, add 20.2 (0.4 g, 0.68 mmol, 1.0 eq) and ethyl acetate (6.0 mL) and stir to dissolve. HCl / ethyl acetate is added to adjust the pH of the reaction solution to approximately 3-4. Methyl tert-butyl ether (1.5 mL) is added and stirred for 1 hour to allow crystallization. Filter and dry to obtain a white solid (0.41 g, 97.62% yield).

[0310] 1H NMR (400MHz, CDCl3) δ8.11 (s, 5H), 7.19 (d, J=7.7Hz, 2H), 6.80 (d, J=7.6Hz, 2H), 5.0 9(s, 1H), 4.57(s, 1H), 4.43(s, 1H), 3.30(s, 1H), 3.06(s, 1H), 2.43(t, J=8.3Hz, 1H), 2.24(s, 1H), 2.09(s, 3H), 1.90(s, 1H), 1.82-1.56(m, 5H), 1.49(s, 5H), 1.38-1.20( m, 4H), 1.22-1.07 (m, 4H), 1.07-0.86 (m, 8H), 0.77 (s, 3H), 0.70 (s, 1H), 0.56 (s, 3H).

[0311] MS: m / z[M+H] + 581.4.

[0312] Example 21. Synthesis of Compound 21 Hydrochloride

[0313]

[0314] Preparation of intermediate 21.1:

[0315] To a 100 mL reaction flask, L-HO-Asn-Boc (2.00 g, 8.63 mmol, 1.2 eq), EDCI (1.65 g, 8.63 mmol, 1.2 eq), HOBt (0.2 g, 1.40 mmol, 1.2 eq), N,N-diisopropylethylamine (1.86 g, 14.38 mmol, 2.0 eq) and dichloromethane (30 mL) were added and stirred under ice bath until homogeneous. 1.3 (3.00 g, 7.19 mmol, 1.0 eq) was then added to the reaction solution, followed by stirring at room temperature for 3 hours. The reaction was confirmed to be complete by TLC. The reaction solution was adjusted to neutrality with 1.0 M hydrochloric acid, separated, washed with saturated NaHCO3 aqueous solution, and dried over anhydrous sodium sulfate. The solution was filtered, concentrated under reduced pressure, and the solvent evaporated to give a white solid (4.17 g, 91.85% yield).

[0316] Preparation of intermediate 21.2:

[0317] To a 100 mL reaction flask, add 21.1 (4.17 g, 6.60 mmol, 1.0 eq) and dichloromethane (40 mL) and stir until homogeneous. Add trifluoroacetic acid (12 mL) and stir at room temperature for 1 hour. The reaction is complete as determined by TLC. Evaporate the solvent to obtain a colorless oil, which is dissolved in dichloromethane and the pH of the solution is adjusted to approximately 8 with saturated sodium bicarbonate. Separate the layers and remove the organic phase, dry it over anhydrous sodium sulfate, and evaporate the solvent to obtain a colorless oil (3.01 g, 86.00% yield).

[0318] Preparation of compound 21 hydrochloride:

[0319] To a 50 mL reaction flask, add 21.2 (3.00 g, 6.57 mmol, 1.0 eq) and ethyl acetate (30 mL) and stir to dissolve. Add hydrogen chloride in ethyl acetate to adjust the pH of the reaction solution to approximately 3-4. Once the reaction solution is clear, add methyl tert-butyl ether and stir to crystallize. Filter to obtain a white solid (1.8 g, 56.25% yield).

[0320] 1 H NMR (400MHz, CDCl3) δ8.63 (d, J=8.1Hz, 1H), 8.23 ​​(brs, 3H), 7.81 (s, 1H), 7.02 (s, 1H), 5.06 (s, 1H) , 4.80 (s, 1H), 4.46 (dd, J=8.3, 4.2Hz, 1H), 3.11 (s, 2H), 2.52 (t, J=8.8Hz, 1H), 2.28 (d, J=9.6Hz, 1H ), 2.11 (s, 3H), 2.01 (d, J = 10.8Hz, 1H), 1.81-1.56 (m, 6H), 1.56-1.44 (m, 4H), 1.37 (d, J = 21.9Hz, 1 H), 1.26 (qd, J=6.3, 5.9, 3.3Hz, 2H), 1.19 (s, 6H), 0.99 (t, J=7.3Hz, 7H), 0.79 (s, 4H), 0.61 (s, 3H).

[0321] MS: m / z[M+H] + 532.4.

[0322] Example 22. Synthesis of Compound 22 Hydrochloride

[0323]

[0324] Preparation of Intermediate 22.1:

[0325] To a 100 mL reaction flask, L-HO-Arg-Boc (3.23 g, 8.63 mmol, 1.2 eq), EDCI (1.65 g, 8.63 mmol, 1.2 eq), HOBt (0.2 g, 1.40 mmol, 1.2 eq), N,N-diisopropylethylamine (1.86 g, 14.38 mmol, 2.0 eq) and dichloromethane (3 mL) were added and stirred under ice bath until homogeneous. 1.3 (3.00 g, 7.19 mmol, 1.0 eq) was then added to the reaction solution and stirred at room temperature for 3 hours. The reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to neutral with 1.0 M hydrochloric acid, the layers were separated, and the organic phase was washed with saturated NaHCO3 and dried over anhydrous sodium sulfate. The organic phase was concentrated to obtain a light yellow oil (4.21 g, 86.98% yield).

[0326] Preparation of intermediate 22.2:

[0327] To a 100 mL reaction flask, add 22.1 (4.21 g, 6.25 mmol, 1.0 eq) and dichloromethane (40 mL). Stir until homogeneous. Add trifluoroacetic acid (12 mL) and stir at room temperature for 1 hour. The reaction is complete as determined by TLC. Evaporate the solvent to obtain a colorless oil, which is dissolved in dichloromethane and washed with saturated aqueous NaHCO3 solution. The pH of the aqueous phase is 7-8. Separate the liquids and dry the organic phase over anhydrous sodium sulfate. Filter and concentrate to obtain a colorless oil (3.23 g, 90.23% yield).

[0328] Preparation of compound 22 hydrochloride:

[0329] To a 100 mL reaction flask, add 22.2 (3.23 g, 5.63 mmol, 1.0 eq) and isopropanol (20 mL) and stir until dissolved. Add hydrogen chloride in ethyl acetate to adjust the pH of the reaction solution to approximately 3-4, and stir for 1 hour to allow crystallization. Filter and dry under vacuum at 40°C for 4 hours using an oil pump to obtain 0.84 g of a white solid (yield 22.46%). 1H NMR (400MHz, CDCl3) δ8.53 (s, 1H), 8.28 (s, 3H), 7.54 (s, 1H), 6.96 (s, 4H), 5.07 (s, 1H) ), 4.53 (s, 1H), 4.45 (s, 1H), 3.35 (d, J = 28.0Hz, 2H), 2.51 (s, 1H), 2.29 (s, 1H), 2.11 (s , 3H), 2.02(s, 1H), 1.87(s, 2H), 1.67(s, 6H), 1.48(s, 5H), 1.41(s, 2H), 1.33-1.23(m, 2H), 1.23-1.08 (m, 5H), 1.00 (d, J=6.1Hz, 7H), 0.91 (s, 1H), 0.79 (s, 4H), 0.61 (s, 3H).

[0330] MS: m / z[M+H] + 574.4.

[0331] Example 23. Synthesis of Compound 23 Hydrochloride

[0332]

[0333] Preparation of Intermediate 23.1:

[0334] To a 250 mL single-necked reaction flask were added compound 14.2 (5.0 g, 13.3 mmol), Boc-L-Ala-OH (3.0 g, 15.9 mmol), dichloromethane (50 mL), triethylamine (1.6 g, 16.0 mmol), HOBT (0.7 g, 5.1 mmol), and EDCI (3.1 g, 16.2 mmol). The mixture was reacted at room temperature for 4 hours, then washed with saturated aqueous NaHCO₃. The product was concentrated under reduced pressure and the crude product was purified by column chromatography (petroleum ether (60-90) / ethyl acetate 10:1-2:1) to afford a white solid (6.5 g, 89.3% yield).

[0335] Preparation of intermediate 23.2:

[0336] Compound 23.1 (3.5 g, 6.4 mmol, 1.0 eq) and dichloromethane (18 mL) were added to a 250 mL three-necked reaction flask. Under nitrogen protection and magnetic stirring, trifluoroacetic acid (7.3 g, 64 mmol) was added at 0°C, followed by reaction at room temperature for 3 hours. The mixture was concentrated under reduced pressure, dichloromethane (100 mL) was added, and the mixture was washed with saturated sodium bicarbonate aqueous solution. The organic phases were combined and dried over anhydrous sodium sulfate. Filtered and concentrated to obtain a white solid (2.6 g, 90.9% yield).

[0337] Preparation of compound 23 hydrochloride:

[0338] To a 250 mL single-necked reaction flask, compound 23.2 (2.6 g, 5.85 mmol, 1.0 eq) and ethyl acetate (20 mL) were added. Under nitrogen protection and magnetic stirring, HCl / ethyl acetate (3 M, 2.4 mL, 7.2 mmol) was added at room temperature. Stirring was continued for 3 hours. A white solid precipitated, which was filtered and washed with ethyl acetate (5 mL). Drying was performed under oil vacuum at 40°C for 3 hours to obtain a white solid (2.1 g, 74.6% yield).

[0339] 1 H NMR (400MHz, CDCl3) δ8.66-8.46(m, 1H), 8.16(brs, 3H), 5.18-5.02(m, 1H), 4.70-4.52(m, 1H), 4.44-3.78(m , 2H), 2.53 (d, J=9.1Hz, 1H), 2.28-1.96 (m, 2H), 2.11 (s, 3H), 1.93-0.70 (m, 23H), 0.79 (s, 3H), 0.61 (s, 3H).

[0340] MS: m / z[M+H] + 447.6.

[0341] Example 24. Solubility test

[0342] Test Method

[0343] Weigh an appropriate amount of the compound of the invention and prepare a solution using different media. Stir in a 25°C constant temperature water bath with a magnetic stirrer for approximately 24 hours. Filter through a 0.22 μm aqueous filter membrane. Take an appropriate amount of the filtrate and dilute it with methanol to a specific concentration to prepare the test solution. Determine the concentration of the test solution by HPLC with a UV detector, using methanol as a blank control solution.

[0344] (1) Blank solution: methanol

[0345] (2) Reference substance solution: Weigh 5 mg of reference substance accurately, place in a 10 mL volumetric flask, dissolve in methanol and dilute to the mark, mix well, and the solution is ready.

[0346] (3) Sample solution: Pipette an appropriate amount of sample solution, dilute it with methanol to about 0.5 mg / mL (determined by the concentration of each sample), and mix well.

[0347] Liquid chromatograph Waters Acquity Arc detector 2998 PDA Detector Chromatographic columns Waters Acquity UPLC BEH C18 3.0*100mm*1.7μm Mobile phase <![CDATA[0.1% H3PO4 (pH adjusted to 7.5 with ammonia water) ∶ acetonitrile = 2 ∶ 8]]> flow rate 0.3mL / min Injection volume 10 μL Column oven 35℃ Sample tray Not temperature controlled Detection wavelength 205nm

[0348] Test results

[0349]

[0350]

[0351] “ / ” indicates untested; when the solubility is a specific value, it is expressed as “saturated solubility”; when it is “>10”, it means the solubility is higher than 10 mg / mL.

[0352] Example 25. Stability of the compounds of the present invention in glucose solution

[0353] Test Method

[0354] An appropriate amount of the derivative of the present invention was weighed and dissolved in 5% glucose solution to a concentration of approximately 1 mg / g. After stirring in a 25°C water bath with a magnetic stirrer for approximately 24 hours, the solution was filtered through a 0.22 μm aqueous filter membrane. The clarified solution was diluted with methanol to a desired concentration to serve as the test sample solution. The sample was then allowed to stand at room temperature for 0, 1, 3, 5, and 8 hours. The solution stability of the test sample was determined by HPLC with UV detection using methanol as the blank solvent.

[0355] (1) Blank solution: methanol.

[0356] (2) Sample solution: Take an appropriate solution and filter it through a 0.22 μm filter membrane.

[0357]

[0358] Test results

[0359]

[0360] Conclusion: The above results show that the derivatives of the present invention have certain stability after being stored in glucose aqueous solution for a certain period of time. In particular, when R 1 When the group is isopropyl, the purity of the derivative in glucose solution remains basically unchanged.

[0361] Example 26. Pharmacokinetics test of the compounds of the present invention

[0362] This study aimed to investigate the pharmacokinetic (PK) properties of each compound of the present invention dissolved in a 5% Tween 20 aqueous solution in SD rats after a single oral administration of each compound solution, allopregnanolone solution, to measure the active component, allopregnanolone, in plasma.

[0363] Male SD rats weighing 180-220 g were used in this example and purchased from Shanghai Slake Laboratory Animal Co., Ltd. All animals were fasted overnight and fed 4 hours after administration.

[0364] A randomized block design was used to group SD rats into groups of 5 each, each consisting of the allopregnanolone group, the compound 1 hydrochloride group, the compound 2 hydrochloride group, the compound 14 hydrochloride group, and the compound 15 hydrochloride group. Each group was administered by gavage (ig) at a dose of 20 mg / kg (calculated as allopregnanolone).

[0365] At 0.0833, 0.25, 0.5, 1, 2, 3, 4, 6, 9, 12, and 24 hours after administration, approximately 0.6 mL of blood samples were collected through a peripheral vein and transferred to commercial centrifuge tubes containing 0.85-1.15 mg of K2 EDTA anticoagulant (Jiangsu Kangjian Medical Products Co., Ltd.). Plasma was centrifuged within 30 minutes after blood collection (at approximately 4°C, at 3000 g for 10 minutes). The plasma was placed in a labeled polypropylene tube, quickly frozen in dry ice, and then stored in an ultra-low temperature freezer at -60°C or lower awaiting detection. The drug concentration in the plasma of SD rats was detected by LC-MS / MS bioanalysis, and the blood drug concentration-time data were analyzed using a non-compartmental model and WinNonlin software package (version 6.3 or newer). The data are shown in Table 3.

[0366]

[0367] “ND” means not calculable.

[0368] Conclusion: The above results show that the derivatives of the present invention have significantly improved pharmacokinetic properties compared to the prototype drug. After administration of the derivatives of the present invention, both AUC and Cmax are significantly improved, and they have long-lasting and sustained-release properties. In particular, when R 1 When it is isopropyl, it can maintain an effective physiological concentration of allopregnanolone in the body for a long time, there is no sudden release phenomenon, and the blood drug concentration curve is flat with small fluctuations.

[0369] All documents mentioned in this application are incorporated herein by reference, just as if each document were incorporated herein by reference individually. It should also be understood that after reading the above teachings of the present invention, those skilled in the art may make various changes or modifications to the present invention, and that such equivalents also fall within the scope of the claims appended hereto.

Claims

1. A compound selected from the group consisting of:

2. A pharmaceutical composition comprising a therapeutically effective dose of the compound according to claim 1 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier and / or excipient.

3. Use of the compound according to claim 1 or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition according to claim 2, in the preparation of a medicament for preventing or treating central nervous system disorders.

4. The use according to claim 3, characterized in that The central nervous system disorder is selected from the group consisting of tremor, sleep disorder, depression, bipolar disorder, anxiety disorder, stress reaction, obsessive-compulsive disorder, schizophrenia, schizoaffective disorder, epilepsy, memory disorder and / or cognitive disorder, dementia, movement disorder, personality disorder, autism, pain, traumatic brain injury, vascular disease, substance abuse disorder and / or withdrawal syndrome or tinnitus, post-traumatic stress disorder, attention deficit hyperactivity disorder, Huntington's disease, Parkinson's disease.

5. The use according to claim 4, characterized in that The tremor is essential tremor; The depression is dysthymic disorder, clinical depression, postpartum or postpartum depression, atypical depression, psychotic major depression, catatonic depression, seasonal affective disorder, dysthymia, double depression, depressive personality disorder, recurrent brief depression, minor depressive disorder, depression due to a chronic medical condition, treatment-resistant depression, refractory depression, suicidal tendencies, suicidal ideation, or suicidal behavior; The epilepsy is an epileptic seizure; The autism is monoetiological autism; The anxiety disorder is generalized anxiety disorder or social anxiety disorder; The pain is neuropathic pain, injury-related pain syndrome, acute pain or chronic pain; The vascular disease is stroke, ischemia or vascular malformation; The substance abuse disorder and / or withdrawal syndrome is addiction to opiates, cocaine and / or alcohol, or insomnia.

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