A gamma-aminobutyric acid derivative, pharmaceutical composition and use

Abstract

The application discloses a gamma-aminobutyric acid derivative, a pharmaceutical composition and application, and relates to a gamma-aminobutyric acid derivative, an enantiomer, a racemate or a pharmaceutically acceptable salt thereof, a compound with a structural formula as shown in formula I: the compound provided by the application has a strong inhibitory effect on the combination of a human voltage-gated calcium ion channel alpha2delta subunit and 3 H] gabapentin, an IC 50 value of 15.2 nM is measured, and the compound can be used for preparing a therapeutic drug for chronic nerve pain, epilepsy and anxiety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis, and particularly relates to a gamma-aminobutyric acid derivative, a pharmaceutical composition and application. BACKGROUND

[0002] Chronic neuropathic pain (CNP) is caused by nerve damage due to various reasons, such as long-term diabetes, certain viral infections, cancer, central nervous injury, use of certain chemotherapy drugs, etc. Diabetic peripheral neuropathic pain (DPNP) and postherpetic neuralgia (PHN) are two of the most common chronic neuropathic pains. Chronic neuropathic pain, if not treated or treated poorly, can cause great physical pain to the patient, have a great negative impact on the patient's mood, and cause mental and psychological problems such as insomnia, anxiety, depression, etc., significantly reduce the patient's quality of life and cause a great burden to the family and society.

[0003] The main drugs for chronic neuropathic pain are antidepressants, anticonvulsants and analgesics. Antidepressants for chronic neuropathic pain can be divided into tricyclic antidepressants and other antidepressants. Tricyclic antidepressants include amitriptyline, maprotiline, clomipramine, doxepin, etc. Tricyclic antidepressants have many side effects, such as anticholinergic effects (dry mouth, constipation, blurred vision, drowsiness, weight gain, etc.), central nervous system toxicity (concentration difficulties, seizures, social behavior abnormalities, hallucinations, etc.) and cardiovascular system toxicity (hypotension, tachycardia, arrhythmia, etc.). The combination of these drugs has many precautions and complex drug interactions. Other antidepressants are mainly selective serotonin and / or norepinephrine reuptake inhibitors, such as imipramine, paroxetine, fluoxetine, escitalopram, duloxetine, bupropion, venlafaxine, sertraline, etc. The combination of these drugs also has many precautions and complex drug interactions, which brings many challenges to clinical medication and patient compliance. Anticonvulsants for chronic neuropathic pain are mainly sodium channel and calcium channel drugs, such as gabapentin, pregabalin, lamotrigine, topiramate, carbamazepine, oxcarbazepine, sodium valproate, etc. The dosage of gabapentin is very large, and the effect is better in the range of 1800-3600 mg per day. High-dose interval has absorption saturation phenomenon, and the onset is slow (oral two weeks). Sodium channel blockers represented by lamotrigine and topiramate have many adverse reactions, such as skin rash, nausea and vomiting, dizziness and fatigue, blurred vision, and many precautions for combination and complex drug interactions. Analgesics for chronic neuropathic pain include opioids and tramadol, tapentadol, etc. The mechanism of action of the latter two contains a large proportion of opioid mechanism. Opioid drugs have some effect on neuropathic pain, but the effect is not strong and has many side effects, and has addiction.Studies have shown that duloxetine 60 mg / day and 120 mg / day for the treatment of diabetic peripheral neuropathic pain have a clinical efficiency of only 49% and 52%, respectively (Goldstein, D. J.; et al. Pain, 2005, 116(1-2), 109-118.); gabapentin has a clinical efficiency of 32%, 34% and 43% for post-herpetic neuralgia at daily doses of 1800 mg / day, 2400 mg / day and 3600 mg / day, respectively (Rice, A. S. C; et al. Pain, 2001, 94(2), 215-224; Rowbotham, M.; et al. JAMA, 1998, 280(21), 1837-1842.); pregabalin has a clinical efficiency of 26%-50% for post-herpetic neuralgia at daily doses of 150-600 mg (Dworkin, R. H.; et al. Neurology, 2003, 60(8), 1274-1283; Sabatowski, R.; et al. Pain, 2004, 109(1-2), 26-35.), all of which reflect the difficulties of the currently marketed drugs in terms of therapeutic effectiveness: there is no specific drug for this type of disease, and there is no simple treatment that can prevent or reverse neuropathic lesions or completely relieve pain.

[0004] The voltage-gated calcium channel alpha2delta subunit is an important target for drugs for the treatment of this type of disease, and pregabalin, one of the four drugs approved by the FDA for the treatment of diabetic peripheral neuropathic pain (pregabalin, duloxetine, fluoxetine and tapentadol), acts on this target (Field, M. J.; et al. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 17537-17542). Voltage-gated calcium channel alpha2delta subunit ligands, such as gabapentin, pregabalin and mirogabalin, are used not only for the treatment of chronic neuropathic pain, but also for the treatment of epilepsy (pregabalin, FDA-approved indication) and anxiety (pregabalin, EMA-approved indication).

[0005] US6635673, US20030199567 and US20030212133 disclose a class of gamma-aminobutyric acid structures containing a four-membered ring for the treatment of various diseases, including pain, anxiety and epilepsy:

[0006]

[0007] wherein,

[0008] R = H or lower alkyl,

[0009] R 9 ~R 14 Each can be selected independently as H, or as a straight-chain or branched alkyl group containing 1 to 6 carbon atoms.

[0010] US6635673 discloses an embodiment of the above general formula:

[0011]

[0012] This compound is effective against the α2δ subunit from pig brain and [ 3 H] Gabapentin binding inhibition of IC 50 =0.598 μM. From the IC50 of this compound... 50 Based on the results, this compound exhibits weak activity and does not possess drug-like properties.

[0013] Therefore, it is necessary to develop a new γ-aminobutyric acid derivative. Summary of the Invention

[0014] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a γ-aminobutyric acid derivative.

[0015] A second aspect of the present invention also provides a pharmaceutical composition.

[0016] A third aspect of the present invention also provides the use of a γ-aminobutyric acid derivative or pharmaceutical composition.

[0017] According to a first aspect of the present invention, a γ-aminobutyric acid derivative, its enantiomer, racemate, or a pharmaceutically acceptable salt thereof, characterized in that the structural formula of the γ-aminobutyric acid derivative is shown in Formula I:

[0018]

[0019] The γ-aminobutyric acid derivatives according to embodiments of the present invention have at least the following beneficial effects:

[0020] The compounds of this invention affect the α2δ subunit of human voltage-gated calcium ion channels and [ 3 The binding of H]gabapentin exhibits strong inhibitory activity, and its IC50 value was measured. 50 With a value of 15.2 nM, it can be used to prepare therapeutic drugs for chronic neuropathic pain, epilepsy, and anxiety.

[0021] According to some embodiments of the present invention, the racemic mixture is composed of the following formulas Ia and Ib:

[0022]

[0023] According to some embodiments of the present application, the method for preparing the gamma-aminobutyric acid derivative, the enantiomer, the racemate or the pharmaceutically acceptable salt thereof comprises the following steps:

[0024] S1, reacting compound 2 with a combination of activated zinc powder and CCl3COCl or a combination of triethylamine and CHCl2COCl to obtain compound 3;

[0025] S2, reacting compound 3 with a combination of zinc powder and acetic acid or a combination of n-Bu3SnH and 2,2'-azobisisobutyronitrile to obtain compound 4;

[0026] S3, reacting compound 4 with tert-butyl diethylphosphorylacetate in the presence of a first base to obtain compound 5;

[0027] S4, reacting compound 5 with nitromethane in the presence of a second base to obtain compound 6;

[0028] S5, reducing compound 6 with iron powder to obtain compound 7.

[0029] S6, reacting compound 7 with Boc2O to obtain compound 8;

[0030] S7, oxidizing compound 8 with OsO4 / N-methylmorpholine N-oxide or KMnO4 / NaOH to obtain compound 9;

[0031] S8, reacting compound 9 with NaIO4 to obtain compound 10;

[0032] S9, reducing compound 10 with a reducing agent to obtain compound 11;

[0033] S10, treating compound 11 with iodine / triphenylphosphine / imidazole to obtain compound 12;

[0034] S11, reducing and deiodinating compound 12 with catalytic hydrogenation to obtain compound 13;

[0035] S12, removing the tert-butyloxycarbonyl and tert-butyl ester of compound 13 with trifluoroacetic acid to obtain compound of formula 1.

[0036] wherein the structural formulas of compounds 2-13 are as follows:

[0037]

[0038] According to some embodiments of the present application, the first base is selected from at least one of EtONa, t-BuONa, t-BuOK, NaH, lithium diisopropylamide (LDA), lithium bis(trimethylsilyl)amide, sodium bis(trimethylsilyl)amide, and potassium bis(trimethylsilyl)amide.

[0039] According to some embodiments of the application, the second base is selected from an inorganic base or an organic base, such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), triethylamine, diisopropylethylamine, Na2CO3, K2CO3, Cs2CO3, NaOH, KOH, CsOH, EtONa, t-BuONa, t-BuOK, NaH.

[0040] According to some embodiments of the application, the reducing agent is selected from NaBH4, KBH4.

[0041] A second aspect of the application provides a pharmaceutical composition comprising a pharmaceutically acceptable excipient and a pharmaceutical active ingredient comprising the gamma-aminobutyric acid derivative, its enantiomer, racemate or pharmaceutically acceptable salt thereof as described above.

[0042] According to some embodiments of the application, the pharmaceutical active ingredient comprises 5% to 50% of the total mass of the pharmaceutical composition.

[0043] According to some embodiments of the application, the pharmaceutically acceptable excipient comprises at least one of a solvent, an excipient, a diluent, a binder, a disintegrant, a dispersant, a flavoring agent, a suspending agent, a surfactant, an isotonic agent, a thickening agent, an emulsifying agent, a preservative, a glidant or a lubricant.

[0044] According to some embodiments of the application, the pharmaceutically acceptable excipient includes, but is not limited to, ion exchangers; alumina; aluminum stearate; lecithin; serum proteins, such as human serum albumin; buffer substances such as phosphates; glycine; sorbic acid; potassium sorbate; partial glyceride mixtures of saturated vegetable fatty acids; water; salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts; colloidal silica; magnesium trisilicate; polyvinyl pyrrolidone; polyacrylates; waxes; polyethylene-polyoxypropylene- block polymers; wool fat; sugars such as lactose, glucose, and sucrose; starches such as corn starch and potato starch; cellulose and its derivatives such as sodium carboxymethyl cellulose, ethyl cellulose, and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients such as cocoa butter and suppository waxes; oils such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil, and soybean oil; glycols such as propylene glycol and polyethylene glycol; esters such as ethyl oleate and ethyl laurate; agar; buffering agents such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol; phosphate buffer solutions; and other non-toxic compatible lubricants such as sodium lauryl sulfate and magnesium stearate; coloring agents; releasing agents; coating agents; sweetening agents; flavoring agents; perfuming agents; preservatives; and antioxidants.

[0045] According to some embodiments of the present application, the dosage form of the pharmaceutical composition is at least one of a solid oral preparation, a liquid oral preparation, or an injection.

[0046] According to some embodiments of the present application, the solid oral preparation comprises at least one of a dispersible tablet, an enteric-coated tablet, a chewable tablet, a disintegrating tablet, a capsule, or a granule.

[0047] The third aspect of the present application provides use of the above-mentioned γ-aminobutyric acid derivative, enantiomer, racemate thereof, or pharmaceutically acceptable salt thereof; or the above-mentioned pharmaceutical composition in the preparation of a medicament for treating chronic neuropathic pain.

[0048] The fourth aspect of the present application provides use of the above-mentioned γ-aminobutyric acid derivative, enantiomer, racemate thereof, or pharmaceutically acceptable salt thereof; or the above-mentioned pharmaceutical composition in the preparation of a medicament for treating epilepsy.

[0049] The fifth aspect of the present application provides use of the above-mentioned γ-aminobutyric acid derivative, enantiomer, racemate thereof, or pharmaceutically acceptable salt thereof; or the above-mentioned pharmaceutical composition in the preparation of a medicament for treating anxiety.

[0050] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application.

[0051] The pharmaceutically acceptable salt of the present application includes, but is not limited to, a pharmaceutically acceptable salt formed with various inorganic bases, such as NaOH, KOH, Mg(OH)2, Ca(OH)2, Sr(OH)2, Al(OH)3, etc., or inorganic carbonates, such as Na2CO3, K2CO3, MgCO3, CaCO3, SrCO3, etc., or organic bases, such as amino acids, etc., or inorganic acids, such as hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, hydroiodic acid, etc., or organic acids, such as methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoroacetic acid, malic acid, citric acid, etc. DETAILED DESCRIPTION

[0052] The following are specific embodiments of the present application, and the technical solutions of the present application are further described in conjunction with the embodiments, but the present application is not limited to these embodiments.

[0053] The reagents, methods, and equipment used in the present application are all conventional reagents, methods, and equipment in the technical field unless otherwise specified.

[0054] Example 1

[0055] Example 1 provides a p-toluenesulfonic acid salt of a γ-aminobutyric acid derivative, and the preparation method is as follows:

[0056] The preparation of activated zinc powder is as follows: CuSO4(40.00 g, 0.25 mol) is added to water (1 L) with stirring and dissolved. Zinc powder (600.00 g, 9.17 mol) is added, stirred at room temperature for 3-4 hours and filtered. The filter cake is washed with water (300 mL x 2) and acetone (750 mL x 2) in sequence and dried in a vacuum oven (about 10 mm Hg) at 50 °C for 24-48 hours.

[0057] S1, Compound 2 (10.88 g, 0.14 mol) and activated zinc powder (17.70 g, 0.27 mol) are added to anhydrous tetrahydrofuran (100 mL) with stirring under N2and ice-water bath. A solution of CCI3COCI (19.75 g, 0.11 mol) in anhydrous tetrahydrofuran (20 mL) is added dropwise. The exothermic heat during the dropwise addition is controlled to maintain the internal temperature of the reaction system at 30-35 °C. After the dropwise addition is completed, the reaction system is maintained at 35 °C with stirring overnight. TLC monitoring shows that the reaction is complete, and the reaction solution is cooled to room temperature. Celite is used to assist filtration, and the filtrate is concentrated under reduced pressure on a rotary evaporator to 1 / 3 of its original volume and then poured into ice water (200 mL). The resulting mixture is extracted with CH2CI2(100 mL x 3), and the combined organic phase is washed with brine (100 mL), dried (MgSO4), and concentrated under reduced pressure on a rotary evaporator to give a red oil, which is purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target product compound 3. Pale yellow oil; 5.30 g (20%); this product is used directly in the next step without further characterization.

[0058] S2, Zinc powder (9.07 g, 0.14 mol) and glacial acetic acid (150 mL) are mechanically stirred and mixed in an ice-water bath, and then a freshly prepared solution of compound 3 (5.30 g, 28 mmol) in glacial acetic acid (20 mL) is added dropwise under N2. After the dropwise addition is completed, the reaction mixture is stirred in an oil bath at 55 °C overnight under N2. TLC monitoring shows that the reaction is complete, and the reaction mixture is cooled to room temperature, diluted with CH2CI2(200 mL), and filtered through celite. The filtrate is concentrated on a rotary evaporator to remove CH2CI2and most of the acetic acid, and then poured into ice water (600 mL). Extraction with CH2CI2(150 mL x 3) is performed, and the combined organic phase is washed with saturated NaHCO3until the pH of the aqueous phase reaches > 7, washed with saturated brine (300 mL), dried (MgSO4), and concentrated under reduced pressure on a rotary evaporator to give a brown oil, which is purified by column chromatography [V(EtOAc) / V(n-hexane) = 5 / 95] to give the target product compound 4. Pale yellow oil; 2.17 g (63%); 1H-NMR (CDC13, 500 MHz) δ: 5.85-5.90 (m, 2H), 3.43-3.48 (m, IH), 3.19-3.25 (m 1H), 2.76-2.83 (m, IH), 2.55 (ddd, IH, J = 3.0 Hz, 5.5 Hz and 18.0 Hz), 2.31-2.41 (m, 2H), 2.14-2.19 (m, IH), 2.05-2.11 (m, IH).

[0059] S3, t-BuOK (6.63 g, 59 mmol) was added to anhydrous THF (100 mL) and stirred to form a suspension, and a solution of diethylphosphoryl tert-butyl acetate (14.91 g, 59 mmol) in anhydrous THF (50 mL) was added dropwise. After the dropwise addition was completed, stirring was continued in an ice water bath for 1 hour, and then a solution of compound 4 (3.61 g, 30 mmol) in anhydrous tetrahydrofuran (10 mL) was added dropwise. After the dropwise addition was completed, stirring was continued at room temperature, and TLC showed that the reaction was completed. It was poured into ice water (300 mL), extracted with CH2Cl2(100 mL x 3), washed with 1 M hydrochloric acid (50 mL) and brine in turn, dried (MgSO4), and concentrated under reduced pressure on a rotary evaporator to obtain crude compound 5 (6.51 g, light yellow oil). It was used directly in the next step without purification.

[0060] S4, the above crude compound 5 (6.51 g, estimated at 30 mmol) was added to a solution of CH3NO2(60 mL), and then DBU (9.00 g, 59 mmol) was added, and then the reaction was heated on an oil bath at 80°C overnight. TLC monitoring showed that the reaction was completed. After the reaction mixture was cooled to room temperature, it was poured into 400 mL of ice water, and extracted with CH2Cl2(50 mL x 3). The organic phases were combined and washed with 1 M hydrochloric acid (100 mL) and brine in turn, dried (MgSO4), and concentrated under reduced pressure on a rotary evaporator to obtain a dark red oil crude product, which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to obtain the target product compound 6. Light yellow oil; 3.97 g (total yield from compound 4 to compound 6 was 47%); 1H-NMR (CDC13, 500 MHz) δ: 6.02-6.06 (m, 1H), 5.91-5.94 (m, 1H), 4.77 (s, 2H), 2.73-2.80 (m, 1H), 2.58-2.62 (m, 1H), 2.54 (d, 1H, J = 17.0 Hz), 2.47 (d, 1H, J = 17.5 Hz), 2.10-2.15 (m, 1H), 2.03-2.08 (m, 3H), 1.88-1.93 (m, 1H), 1.63 (dd, 1H, J = 8.5 Hz and 12.5 Hz), 1.48 (s, 9H). 13 C-NMR (CDC13, 126 MHz) δ: 170.98, 128.59, 128.43, 82.01, 81.09, 38.92, 38.56, 36.56, 34.74, 28.22, 27.18, 26.27, 22.57. ESI-HRMS [M+H] + :(m / z) calcd for C 15 H 24 NO4: 282.1700, found: 282.1697.

[0061] S5, Compound 6 (3.97 g, 14 mmol), iron powder (3.94 g, 71 mmol) and NH4CI (1.51 g, 28 mmol) were added successively into 95% EtOH / H2O (60 mL, v / v = 2 / 1) under N2environment, stirred, heated to reflux overnight. TLC monitoring showed the reaction was completed. After cooling to room temperature, the mixture was filtered through celite, the filtrate was concentrated under reduced pressure on a rotary evaporator to remove ethanol to give a white solid. Ethyl acetate (100 mL) and water (100 mL) were added to stir the solid into solution. The organic phase was separated and the aqueous phase was extracted with ethyl acetate (50 mL x 3). The combined organic phase was washed with brine, dried (MgS04), concentrated under reduced pressure on a rotary evaporator to give a solid, which was slurried [V(EtOAc) / V(n-hexane) = 1 / 50] to purify, filtered, and the filter cake was dried under vacuum at room temperature to give the target product compound 7. White solid; 2.14 g (61%); melting point 176.7 °C-177.3 °C; 1H-NMR (CDCI3, 500 MHz) δ: 8.53 (br s, 2H), 6.00-6.04 (m, 1H), 5.90-5.93 (m, 1H), 3.33 (d, 1H, J = 13.0 Hz), 3.27 (d, 1H, J = 13.0 Hz), 2.75-2.82 (m, 1H), 2.62-2.66 (m, 1H), 2.56 (d, 1H, J = 16.5 Hz), 2.53 (d, 1H, J = 16.5 Hz), 2.01-2.13 (m, 4H), 1.86-1.91 (m, 1H), 1.56 (dd, 1H, J = 8.3 Hz and 12.8 Hz), 1.44 (s, 9H). 13 C-NMR (CDCI3, 126 MHz) δ: 172.30, 128.63, 128.51, 81.85, 48.02, 38.57, 38.17, 37.63, 34.86, 28.23, 27.26, 26.10, 22.88. ESI-HRMS [M+H] + : (m / z) calcd for C 15 H 26 NO2: 252.1958, found: 252.1956.

[0062] S6, Compound 7 (5.71 g, 23 mmol) was dissolved in anhydrous CH2CI2(50 mL) under the condition of ice-water bath, then Et3N (6.87 g, 68 mmol) and Boc20 (7.43 g, 34 mmol) in anhydrous CH2CI2(10 mL) were added dropwise. After the addition was completed, the ice-water bath was removed, and stirred at room temperature overnight. TLC monitoring showed that the reaction was completed, then poured into 100 mL ice water, extracted with CH2CI2(100 mL x 2), the combined organic phase was washed with 1 M hydrochloric acid (50 mL) and brine successively, dried over (MgS04), concentrated under reduced pressure on a rotary evaporator, then purified by column chromatography [V(EtOAc) / V(n-hexane) = 5 / 95] to obtain the target product compound 8. Light yellow oil; 7.49 g (93%); 1 H-NMR (DMSO-d6, 500 MHz) δ: 6.77 (t, 1H, J = 6.0 Hz), 5.97-6.01 (m, 1H), 5.84-5.88 (m, 1H), 3.17 (d, 2H, J = 6.5 Hz), 2.49-2.56 (m, 2H), 2.29-2.32 (m, 1H), 2.21 (d, 1H, J = 16.0 Hz), 2.14 (d, 1H, J = 16.0 Hz), 1.87-1.98 (m, 4H), 1.75-1.81 (m, 1H), 1.38 (s, 9H), 1.36 (s, 9H).13 C-NMR (DMSO-d6, 126 MHz) δ: 170.71, 156.24, 128.85, 128.13, 79.28, 77.45, 67.04, 47.21, 37.24, 36.98, 34.19, 28.26, 27.79, 27.16, 25.88, 22.50. ESI-HRMS [M+H] + : (m / z) calcd for C 20 H 34 NO4: 352.2482, found: 352.2480.

[0063] S7, Compound 8 (0.73 g, 2.1 mmol) was added to t-BuOH (10 mL) and deionized water (15 mL) was added with stirring under ice water bath. Then KMnO4(0.23 g, 1.5 mmol) / NaOH (0.05 g, 1.3 mmol) solution prepared with a small amount of water was added dropwise. After the dropwise addition was completed, it was stirred at room temperature for 30 minutes, and TLC monitoring showed that the reaction was completed. 10% Na2S2O3 aqueous solution was added dropwise to the reaction solution until the excess KMnO4was completely consumed, and the purple solution color faded to obtain a mixture which was filtered through diatomite, and the filtrate was concentrated under reduced pressure on a rotary evaporator to remove t-BuOH, adjusted to pH 7 with 1M hydrochloric acid, extracted with CH2Cl2(50 mL x 3), the combined organic phase was dried (MgSO4), and the filtrate was concentrated under reduced pressure on a rotary evaporator to obtain a yellow oil, which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 9 ~ 1 / 1] to obtain the target product compound 9. Yellow oil; 0.38 g. The product was not completely characterized and was directly used in the next step.

[0064] S8, Compound 9 (0.38 g, 1.0 mmol) was dissolved in anhydrous tetrahydrofuran (8 mL) under ice water conditions, deionized water (2 mL) was added, and then NaIO4(0.42 g, 2.0 mmol) was added in portions. After the addition was completed, it was stirred at room temperature for 30 minutes. TLC monitoring showed that the reaction was completed, and Na2S2O3 aqueous solution was added to consume the excess NaIO4. Extracted with ethyl acetate (70 mL x 3), the combined organic phase was washed with brine, dried (MgSO4), and concentrated under reduced pressure on a rotary evaporator to obtain a yellow oil of crude compound 10 (0.56 g), which was not purified and was directly used in the next step.

[0065] S9. Under ice-water bath conditions, crude compound 10 (0.20 g, calculated as 0.52 mmol) was dissolved in 10 mL of 95% EtOH, and then NaBH4 (0.059 g, 1.6 mmol) was added in portions. After the addition was complete, the mixture was transferred to room temperature and stirred for 30 min. TLC monitoring showed that the reaction was complete. The reaction solution was poured into ice water (50 mL), extracted with ethyl acetate (50 mL × 3), the organic phases were combined, washed with brine, dried over (MgSO4), and concentrated under reduced pressure on a rotary evaporator to obtain a yellow oil. The target product compound 11 was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 9 to 1 / 1]. Yellow oil. 0.17 g (total yield of compounds 8 to 11 was 21%). 1 H-NMR (DMSO-d6, 500MHz) δ: 6.75 (t, 1H, J = 6.0Hz), 4.39 (t, 1H, J = 4.8Hz), 4.30 (t, 1H, J = 5.3Hz), 3.20-3.32 (m, 4H), 3.13 (d, 2H, J = 6.5Hz), 2.32 (d, 1 H,J=15.5Hz),2.12-2.25(m,2H),2.22(d,1H,J=15.5Hz),1.87-1.91(m,1H ),1.53-1.61(m,1H),1.45-1.51(m,3H),1.41-1.44(m,1H),1.38(s,18H). 13 C-NMR(DMSO-d6,126MHz)δ:170.75,156.23,79.37,77.44,60.51,59.01,54.91, 47.02,40.19,38.33,38.12,34.46,33.21,29.23,28.25,27.82.ESI-HRMS[M+H] + :(m / z)calcd.for C 20 H 38 NO6:388.2694, found:388.2690.

[0066] S10, under the environment of N2and ice water bath, I2(12.36 g, 49 mmol) was dissolved in anhydrous CH2Cl2(150 mL), PPh3(12.77 g, 49 mmol) was added in portions. After addition, the reaction mixture was stirred for 30 min. Imidazole (9.94 g, 0.15 mol) was added in portions. After addition, the reaction mixture was continued to stir for 30 min, then a solution of compound 11 (6.29 g, 16 mmol) in CH2Cl2(20 mL) was added dropwise. After dropwise addition, it was transferred to room temperature and stirred overnight. TLC monitoring showed that the reaction was completed, 10% Na2S2O3 aqueous solution was added to quench the reaction. Extracted with CH2Cl2(50 mL x 3), the organic phase was combined and washed with brine, dried (MgSO4), concentrated under reduced pressure on a rotary evaporator to obtain a milky white viscous material, purified by column chromatography [V(EtOAc) / V(n-hexane) = 5 / 95] to obtain the target product compound 12. Light yellow oil; 5.03 g (52%); 1 H-NMR (CDC13, 500MHz) δ: 4.99 (t, 1H, J = 6.5 Hz), 3.47 (dd, 1H, J = 7.5 Hz and 14.0 Hz), 3.11-3.18 (m, 2H), 2.93-3.01 (m, 3H), 2.46-2.54 (m, 1H), 2.30-2.41 (m, 1H), 2.34 (d, 1H, J = 13.5 Hz), 2.26 (d, 1H, J = 13.5 Hz), 1.94-2.05 (m, 4H), 1.83-1.90 (m, 1H), 1.57-1.65 (m, 1H), 1.45 (s, 9H), 1.44 (s, 9H). 13 C-NMR (CDC13, 126MHz) δ: 171.36, 156.59, 81.44, 79.47, 48.33, 44.89, 41.50, 39.89, 35.79, 33.21, 33.01, 31.78, 28.56, 28.28, 3.79, 3.00. ESI-HRMS [M+Na] + :(m / z) calcd for C 20 H 35 I2NNaO4: 630.0548, found: 630.0541

[0067] S11, Compound 12 (0.35 g, 0.58 mmol), 10% Pd / C (0.10 g) and Et3N (0.30 g, 3.0 mmol) were added sequentially to MeOH (10 mL), the reaction vessel was purged with hydrogen gas (balloon) according to the standard procedure and stirred at room temperature overnight. TLC monitoring showed the reaction to be complete. The reaction mixture was filtered through celite and the filtrate was concentrated under reduced pressure on a rotary evaporator to give an oily residue which was diluted with ethyl acetate (50 mL). The resulting solution was washed sequentially with 1 M hydrochloric acid and brine, dried (MgS04) and concentrated under reduced pressure on a rotary evaporator to give a pale yellow oil which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target product compound 13. Pale yellow oil; 0.16 g (78%);1H-NMR (CDC13, 500 MHz) δ: 5.00 (t, 1H, J = 6.5 Hz), 3.43 (dd, 1H, J = 7.3 Hz and 13.8 Hz), 3.19 (dd, 1H, J = 5.5 Hz and 14.0 Hz), 2.37 (d, 1H, J = 13.5 Hz), 2.23-2.28 (m, 1H), 2.26 (d, 1H, J = 14.0 Hz), 2.09-2.14 (m, 1H), 1.89-1.93 (m, 1H), 1.56-1.60 (m, 1H), 1.42-1.53 (m, 2H), 1.44 (s, 9H), 1.43 (s, 9H), 1.27-1.39 (m, 2H), 0.83 (t, 3H, J = 7.3 Hz), 0.79 (t, 3H, J = 7.8 Hz). 1 H-NMR (CDC13, 500 MHz) δ: 5.00 (t, 1H, J = 6.5 Hz), 3.43 (dd, 1H, J = 7.3 Hz and 13.8 Hz), 3.19 (dd, 1H, J = 5.5 Hz and 14.0 Hz), 2.37 (d, 1H, J = 13.5 Hz), 2.23-2.28 (m, 1H), 2.26 (d, 1H, J = 14.0 Hz), 2.09-2.14 (m, 1H), 1.89-1.93 (m, 1H), 1.56-1.60 (m, 1H), 1.42-1.53 (m, 2H), 1.44 (s, 9H), 1.43 (s, 9H), 1.27-1.39 (m, 2H), 0.83 (t, 3H, J = 7.3 Hz), 0.79 (t, 3H, J = 7.8 Hz). 13 C-NMR (CDC13, 126 MHz) δ: 172.37, 156.60, 80.85, 79.02, 48.86, 45.68, 40.88, 40.05, 34.01, 33.53, 28.55, 28.27, 24.07, 19.03, 13.83, 11.73. ESI-HRMS [M+H] + :(m / z) calcd for C 20 H 38 NO4: 356.2795, found: 356.2789.

[0068] S12, Compound 13 (0.21 g, 0.59 mmol) was dissolved in CH2Cl2(3 mL) and CF3CO2H (2 mL) was added and stirred at room temperature until TLC monitoring showed the reaction was complete. The reaction was concentrated on a rotary evaporator under reduced pressure to give a yellow oil. The oil was dried on a vacuum oil pump to give the compound of Formula I. The sample of the compound of Formula I was dissolved in ethyl acetate (3 mL) / methanol (1 mL) and a solution of p-TsOH-H2O (0.24 g, 1.3 mmol) was added dropwise under an ice water bath, with a minimum amount of ethyl acetate to dissolve, and stirred until a white solid precipitated. Stirring at room temperature for 1 h, filtration, washing the filter cake with ethyl acetate (1 mL), and drying under vacuum gave the p-toluenesulfonic acid salt of the compound of Formula I. White solid; 0.078 g (66%); melting point 126.7 °C-130.9 °C; 1 H-NMR (CD3OD, 500 MHz) δ: 7.70 (d, 2H, J = 8.5 Hz), 7.23 (d, 2H, J = 7.5 Hz), 3.27 (d, 1H, J = 13.0 Hz), 3.22 (d, 1H, J = 13.0 Hz), 2.65 (d, 1H, J = 16.5 Hz), 2.57 (d, 1H, J = 16.5 Hz), 2.37 (s, 3H), 2.26-2.34 (m, 1H), 2.06-2.16 (m, 2H), 1.55-1.64 (m, 3H), 1.33-1.48 (m, 2H), 0.89 (t, 3H, J = 7.5 Hz), 0.82 (t, 3H, J = 7.3 Hz). 13 C-NMR (CD3OD, 126 MHz) δ: 175.79, 143.57, 141.66, 129.80, 126.97, 48.75, 46.24, 38.86, 38.68, 34.97, 34.43, 24.71, 21.30, 19.78, 13.76, 11.73. ESI-HRMS [M (free base) + H] + : (m / z) calcd for C 11 H 22 NO2: 200.1645, found: 200.1642.

[0069] Example 2

[0070] Example 2 provides a pharmaceutical capsule, the component amounts and method of preparation are as follows:

[0071]

[0072]

[0073] The compound prepared in Example 1, pregelatinized starch and microcrystalline cellulose are sieved, mixed well, a solution of polyvinylpyrrolidone is added, mixed, a soft mass is prepared, sieved, wet granules are prepared, dried at 50-60°C, magnesium stearate and talc are sieved beforehand and then added to the granules, the capsules are filled and this gives the finished product.

[0074] Comparative Example 1

[0075] Comparative Example 1 provides a method for preparing Compound II and its p-toluenesulfonic acid salt, which is as follows:

[0076]

[0077] Step 1: Preparation of Compound 15

[0078] A 500 mL three-necked round-bottomed flask containing dicyclopentadiene (14, 250.00 g, 1.9 mol) is fitted with a thermometer on one side, a fractionating column on the middle, and a distillation head with a thermometer and a condenser on the top. The condenser is cooled with a -10°C flowing low-temperature bath. After purging the whole system with N2for 1 minute, the flask is heated to an internal temperature of 160°C, and cyclopentadiene (15) is produced at about 40°C as a distillate under normal pressure. Colorless liquid; 237.90 g (95%). Cyclopentadiene (15) is used directly in the next step without structural characterization.

[0079] Step 2: Preparation of Compound 16

[0080] Freshly distilled cyclopentadiene 15 (50.00 g, 0.76 mol) and CHCl2COCl (156.08 g, 1.06 mol) are dissolved in anhydrous n-hexane (600 mL). After cooling with an ice-water bath under stirring, a solution of Et3N (114.81 g, 1.13 mol) in anhydrous n-hexane (200 mL) is added dropwise under N2. The dropwise addition of Et3N causes an exothermic reaction, and the addition rate should be adjusted so that the temperature of the reaction mixture is maintained at 35-40°C. After the dropwise addition is completed, the ice-water bath is removed, and the system is stirred in an oil bath at 35°C for 2 hours and then at room temperature overnight. The reaction mixture is poured into ice water (1 L), and the organic phase is separated. The aqueous phase is extracted with n-hexane (1 L). The combined organic phases are washed with saturated NaHCO3(200 mL) and brine, dried (MgSO4), and concentrated on a rotary evaporator under reduced pressure to give a red oil. The target product, compound 16, is obtained by distillation under reduced pressure. Colorless oil; 80-98°C / 5 mmHg; 104.32 g (78%). The product is used directly in the next step.

[0081] Step 3: Preparation of Compound 17

[0082] To a stirred solution of compound 16 (250.00 g, 1.4 mol) in acetic acid (100 mL) was added zinc dust (458.96 g, 7.0 mol) under N2atmosphere. The reaction mixture was stirred at 55 °C in an oil bath overnight. TLC monitoring showed the reaction was complete. The reaction mixture was cooled to room temperature, diluted with CH2Cl2(200 mL), and filtered through celite. The filtrate was concentrated on a rotary evaporator, diluted with ice water (1.5 L), and extracted with CH2Cl2(300 mL x 3). The organic phase was washed with saturated NaHCO3until the pH of the aqueous phase reached >7, washed with saturated brine (300 mL), dried (MgSO4), and concentrated on a rotary evaporator under reduced pressure to give a brown oil. The target product, compound 17, was obtained by distillation under reduced pressure. Pale yellow oil; 80-110 °C / 50 mmHg; 143.86 g (95%);1H-NMR (CDC13, 500 MHz) δ: 5.84-5.86 (m, 1H), 5.79-5.81 (m, 1H), 3.85-3.90 (m, 1H), 3.46-3.50 (m, 1H), 3.32 (ddd, 1H, J = 3.0 Hz, 8.5 Hz and 17.0 Hz), 2.67-2.74 (m, 2H), 2.45-2.52 (m, 1H). 1 H-NMR (CDC13, 500 MHz) δ: 5.84-5.86 (m, 1H), 5.79-5.81 (m, 1H), 3.85-3.90 (m, 1H), 3.46-3.50 (m, 1H), 3.32 (ddd, 1H, J = 3.0 Hz, 8.5 Hz and 17.0 Hz), 2.67-2.74 (m, 2H), 2.45-2.52 (m, 1H).

[0083] Step 4: Preparation of compound 18

[0084] To a stirred solution of compound 16 (250.00 g, 1.4 mol) in acetic acid (100 mL) was added zinc dust (458.96 g, 7.0 mol) under N2atmosphere. The reaction mixture was stirred at 55 °C in an oil bath overnight. TLC monitoring showed the reaction was complete. The reaction mixture was cooled to room temperature, diluted with CH2Cl2(200 mL), and filtered through celite. The filtrate was concentrated on a rotary evaporator, diluted with ice water (1.5 L), and extracted with CH2Cl2(300 mL x 3). The organic phase was washed with saturated NaHCO3until the pH of the aqueous phase reached >7, washed with saturated brine (300 mL), dried (MgSO4), and concentrated on a rotary evaporator under reduced pressure to give a brown oil. The target product, compound 17, was obtained by distillation under reduced pressure. Pale yellow oil; 80-110 °C / 50 mmHg; 143.86 g (95%);1H-NMR (CDC13, 500 MHz) δ: 5.84-5.86 (m, 1H), 5.79-5.81 (m, 1H), 3.85-3.90 (m, 1H), 3.46-3.50 (m, 1H), 3.32 (ddd, 1H, J = 3.0 Hz, 8.5 Hz and 17.0 Hz), 2.67-2.74 (m, 2H), 2.45-2.52 (m, 1H).

[0085] Step 5: Preparation of compound 19

[0086] The above crude compound 18 (19.08 g, ca. 92 mmol) was added to a solution of CH3NO2(150 mL) and DBU (28.16 g, 0.18 mol) was added. The reaction was heated at 80 °C on an oil bath overnight. TLC monitoring showed that the reaction was complete. After the reaction mixture was cooled to room temperature, it was poured into 500 mL of ice water and extracted with CH2Cl2(150 mL x 3). The organic phases were combined and washed with 1 M hydrochloric acid (100 mL) and brine successively, dried (MgSO4), and concentrated on a rotary evaporator under reduced pressure to give a dark red oil of crude product, which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target product compound 19. Light yellow oil; 14.00 g (57% overall yield from compound 17 to compound 19). 1 H-NMR (CDC13, 500 MHz) δ: 5.82-5.84 (m, 1H), 5.78-5.80 (m, 1H), 4.79 (d, 1H, J = 12.0 Hz), 4.76 (d, 1H, J = 12.0 Hz), 3.24-3.29 (m, 1H), 2.97-3.01 (m, 1H), 2.62 (d, 1H, J = 17.0 Hz), 2.58 (d, 1H, J = 17.0 Hz), 2.52-2.58 (m, 1H), 2.37-2.42 (m, 1H), 2.31 (dd, 1H, J = 9.0 Hz and 13.0 Hz), 1.75 (ddd, 1H, J = 1.0 Hz, 4.0 Hz and 13.0 Hz), 1.44 (s, 9H). 13 C-NMR (CDC13, 126 MHz) δ: 170.88, 135.07, 131.82, 82.65, 81.20, 42.58, 40.48, 39.73, 38.02, 36.70, 34.57, 28.22. ESI-HRMS [M+H] + : (m / z) calcd for C 14 H 22 NO4: 268.1543, found: 268.1544.

[0087] Step 6: Preparation of compound 20

[0088] Compound 19 (14.00 g, 52 mmol), iron powder (21.93 g, 0.39 mol) and NH4CI (8.40 g, 0.16 mmol) were added into 95% EtOH / H2O (135 mL, v / v = 2 / 1) solution successively, stirred and refluxed overnight under N2environment, TLC monitored the completion of the reaction. After the reaction solution was cooled to room temperature, it was filtered with celite, the filtrate was concentrated to remove ethanol on a rotary evaporator, and the solid was precipitated. The solid was dissolved in ethyl acetate (200 mL) and water (100 mL), shaken, the organic phase was separated, and the aqueous phase was extracted with ethyl acetate (200 mL x 2). The combined organic phase was washed with brine, dried (MgS04), and concentrated under reduced pressure on a rotary evaporator to obtain compound 20 (free base) as a yellow oil. A small amount of p-TsOH-H2O (11.28 g, 59 mmol) in ethyl acetate was added dropwise to a solution of crude compound 20 (free base) in ethyl acetate (100 mL) with stirring, and a white solid was precipitated. After stirring for another hour, it was filtered, the filter cake was washed with ethyl acetate (20 mL), and vacuum dried to obtain the target product compound 20 p-toluenesulfonate. White solid; 15.83 g (75%); melting point 116.4-121.2 °C; 1 H-NMR (DMSO-d6, 500 MHz) δ: 7.73 (brs, 3H), 7.48 (d, 2H, J = 8.0 Hz), 7.12 (d, 2H, J = 7.5 Hz), 5.82-5.84 (m, 1H), 5.77-5.79 (m, 1H), 3.07-3.17 (m, 3H), 2.77-2.81 (m, 1H), 2.40-2.48 (m, 3H), 2.27-2.32 (m, 1H), 2.29 (s, 3H), 2.17 (dd, 1H, J = 9.0 Hz and 12.5 Hz), 1.50 (dd, 1H, J = 4.3 Hz and 12.8 Hz), 1.39 (s, 9H). 13 C-NMR (D2O, 126 MHz) δ: 173.06, 142.47, 139.35, 135.03, 131.62, 129.42, 125.33, 83.21, 47.71, 41.51, 39.62, 38.27, 37.82, 35.73, 34.05, 27.19, 20.44. ESI-HRMS [M (free base) + H] + : (m / z) calcd for C 14 H 24 NO2: 238.1802, found: 238.1800.

[0089] Step 7: Preparation of compound 21

[0090] Compound 20 p-toluenesulfonic acid salt (15.83 g, 39 mmol) was added to a mixture of saturated NaHC03(200 mL) and ethyl acetate (150 mL) and stirred for 10 min. The organic phase was separated and the aqueous phase was extracted with ethyl acetate (150 mL x 2). The organic phases were combined, washed with brine, dried (MgS04) and concentrated on a rotary evaporator to give compound 20 (free base) as a light yellow oil. The free base compound 20 was dissolved in anhydrous tetrahydrofuran (100 mL) under an ice-water bath, and a solution of Et3N (11.73 g, 0.12 mmol) and Boc20 (16.87 g, 77 mmol) in anhydrous tetrahydrofuran (30 mL) was added dropwise. After the addition was completed, the ice-water bath was removed and the mixture was stirred at room temperature overnight. TLC monitoring showed that the reaction was completed, and the mixture was poured into 300 mL of ice water and extracted with ethyl acetate (200 mL x 2), washed with 1 M hydrochloric acid (50 mL) and brine successively, dried (MgS04) and concentrated under reduced pressure on a rotary evaporator, and then purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target product compound 21 as a white solid. White solid; 10.56 g (82%); melting point 84.1-85.4 °C; 1 H-NMR (CDC13, 500 MHz) δ: 5.80-5.82 (m, 1H), 5.72-5.74 (m, 1H), 4.94 (br s, 1H), 3.36 (dd, 1H, J = 6.5 Hz and 14.0 Hz), 3.28 (dd, 1H, J = 6.3 Hz and 13.8 Hz), 3.20-3.22 (m, 1H), 2.75-2.78 (m, 1H), 2.39-2.52 (m, 2H), 2.36 (s, 2H), 2.10 (dd, 1H, J = 8.8 Hz and 12.3 Hz), 1.63 (dd, 1H, J = 4.5 Hz and 12.5 Hz), 1.45 (s, 9H), 1.43 (s, 9H). 13 C-NMR (CDC13, 126 MHz) δ: 172.03, 156.62, 135.57, 131.28, 80.86, 79.19, 49.61, 42.28, 41.05, 40.38, 40.20, 36.77, 34.55, 28.55, 28.25. ESI-HRMS [M+H] + : (m / z) calcd for C 19 H 32 NO4: 338.2326, found: 338.2322.

[0091] Step 8: Synthesis of compound 22

[0092] Compound 21 (3.00 g, 8.9 mmol) was added to a solution of t-BuOH (30 mL) and deionized water (15 mL) under ice water bath with stirring. Then a solution of KMnO4(1.97 g, 12 mmol) / NaOH (0.45 g, 11 mmol) prepared in a small amount of water was added dropwise. After the addition was completed, the reaction was stirred at room temperature for 30 minutes. TLC monitoring showed that the reaction was completed. A 10% aqueous solution of Na2S2O3was added dropwise to the reaction until the excess KMnO4was completely consumed and the purple solution color faded. The resulting mixture was filtered through celite and the filtrate was concentrated under reduced pressure on a rotary evaporator to remove t-BuOH. The solution was adjusted to pH 7 with 1 M hydrochloric acid and extracted with CH2Cl2(100 mL x 3). The combined organic phases were dried (MgSO4) and the filtrate was concentrated under reduced pressure on a rotary evaporator to give a yellow oil. The target product compound 22 was obtained by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 9 ~ 1 / 1] with preliminary purification. Yellow oil; 1.86 g (56%). The product was not fully characterized and was used directly in the next step.

[0093] Step 9: Preparation of compound 23

[0094] Compound 22 (1.86 g, 5.0 mmol) was dissolved in anhydrous tetrahydrofuran (16 mL) under ice water conditions, deionized water (4 mL) was added, and then NaIO4(2.14 g, 10 mmol) was added in portions. After the addition was completed, the reaction was stirred at room temperature for 30 minutes. TLC monitoring showed that the reaction was completed, and an aqueous solution of Na2S2O3was added to consume the excess NaIO4. Extraction was performed with ethyl acetate (70 mL x 3), the combined organic phases were washed with brine, dried (MgSO4), and concentrated under reduced pressure on a rotary evaporator to give a yellow oil of crude compound 23 (1.90 g). No purification was performed and the product was used directly in the next step.

[0095] Step 10: Preparation of compound 24

[0096] To a solution of compound 23 (1.90 g, calculated for 5.1 mmol) in 95% EtOH (20 mL) was added NaBH4(0.58 g, 15 mmol) portion wise under ice water bath. After the addition was completed, the reaction was stirred at room temperature for 30 min. TLC monitoring showed the reaction was completed. The reaction was poured into ice water (50 mL) and extracted with ethyl acetate (50 mL x 3). The combined organic phase was washed with brine and dried over (MgS04). The solvent was removed under reduced pressure on a rotary evaporator to give a yellow oil. The product was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 9 ~ 1 / 1] to give the target product compound 24. Yellow oil; 1.11 g (33% overall yield from compound 21 to compound 24). 1 H-NMR (CDC13, 500 MHz) δ: 5.15 (br s, 1H), 3.79-3.83 (m, 1H), 3.67-3.72 (m, 1H), 3.50-3.59 (m, 2H), 3.34-3.42 (m, 3H), 3.14-3.18 (m, 1H), 2.53-2.62 (m, 2H), 2.44 (d, 1H, J = 13.5 Hz), 2.29 (d, 1H, J = 14.0 Hz), 1.91-1.95 (m, 1H), 1.80-1.87 (m, 1H), 1.63 (dd, 1H, J = 6.0 Hz and 12.5 Hz), 1.53-1.58 (m, 1H), 1.44 (s, 18H). 13 C-NMR (CDC13, 126 MHz) δ: 171.92, 156.97, 81.14, 79.51, 63.58, 62.47, 48.92, 41.21, 40.77, 39.64, 34.43, 29.92, 28.49, 28.23, 28.17. ESI-HRMS [M+H] + : (m / z) calcd for C 19 H 36 NO6: 374.2537, found: 374.2527.

[0097] Step 11: Preparation of compound 25

[0098] I2(4.24 g, 17 mmol) was dissolved in dry CH2Cl2(60 mL) under N2atmosphere and ice water bath. PPh3(4.38 g, 17 mmol) was added portion wise. After addition, the reaction mixture was stirred for 30 min. Imidazole (3.40 g, 50 mmol) was added portion wise. After addition, the reaction mixture was stirred for another 30 min, then a solution of compound 24 (2.00 g, 5.4 mmol) in CH2Cl2(10 mL) was added drop wise. After the addition was completed, the reaction mixture was transferred to room temperature and stirred overnight. TLC monitoring showed the reaction was completed, 10% Na2S2O3aqueous solution was added to quench the reaction. Extracted with CH2Cl2(50 mL x 3), the combined organic phase was washed with brine, dried (MgSO4), concentrated on rotary evaporator under reduced pressure to give a milky white sticky material, which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 5 / 95] to give the target product compound 25. Pale yellow oil; 2.20 g (69%); 1H-NMR (CDC13, 500 MHz) δ: 4.99 (br s, 1H), 3.44 (dd, 1H, J = 7.5 Hz and 14.5 Hz), 3.29 (dd, 1H, J = 6.3 Hz and 9.3 Hz), 3.14-3.19 (m, 2H), 3.02-3.06 (m, 2H), 2.84-2.91 (m, 1H), 2.30-2.35 (m, 1H), 2.32 (d, 1H, J = 13.5 Hz), 2.27 (d, 1H, J = 14.0 Hz), 2.01-2.06 (m, 2H), 1.93-1.99 (m, 1H), 1.63 (dd, 1H, J = 8.0 Hz and 12.5 Hz), 1.46 (s, 9H), 1.44 (s, 9H). 1 H-NMR (CDC13, 500 MHz) δ: 4.99 (br s, 1H), 3.44 (dd, 1H, J = 7.5 Hz and 14.5 Hz), 3.29 (dd, 1H, J = 6.3 Hz and 9.3 Hz), 3.14-3.19 (m, 2H), 3.02-3.06 (m, 2H), 2.84-2.91 (m, 1H), 2.30-2.35 (m, 1H), 2.32 (d, 1H, J = 13.5 Hz), 2.27 (d, 1H, J = 14.0 Hz), 2.01-2.06 (m, 2H), 1.93-1.99 (m, 1H), 1.63 (dd, 1H, J = 8.0 Hz and 12.5 Hz), 1.46 (s, 9H), 1.44 (s, 9H). 13 C-NMR (CDC13, 126 MHz) δ: 171.19, 156.58, 81.56, 79.54, 48.10, 45.44, 40.05, 39.84, 36.10, 35.67, 30.90, 28.55, 28.27, 8.84, 3.36. ESI-HRMS [M+H] + :(m / z) calcd for C 19 H 34 I2NO4: 594.0572, found: 594.0562.

[0099] Step 12: Preparation of compound 26

[0100] Compound 25 (0.89 g, 1.5 mmol), 10% Pd / C (0.20 g) and Et3N (0.46 g, 4.5 mmol) were added sequentially to MeOH (10 mL), the reaction vessel was purged with hydrogen gas (balloon) and placed on a stir bar in a room temperature bath and stirred overnight. TLC monitoring showed the reaction to be complete in 12 h. The reaction mixture was filtered through celite and the filtrate was concentrated on a rotary evaporator under reduced pressure to give an oily residue which was diluted with ethyl acetate (50 mL). The resulting solution was washed sequentially with 1 M hydrochloric acid and brine, dried (MgS04) and concentrated on a rotary evaporator under reduced pressure to give a pale yellow oil which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target product compound 26. Pale yellow oil; 0.383 g (75%); 1 H-NMR (CDC13, 500 MHz) δ: 4.99 (br s, 1H), 3.40 (dd, 1H, J = 7.0 Hz and 14.0 Hz), 3.19 (dd, 1H, J = 6.0 Hz and 14.0 Hz), 2.47-2.54 (m, 1H), 2.38 (d, 1H, J = 13.5 Hz), 2.27 (d, 1H, J = 14.0 Hz), 2.06-2.11 (m, 1H), 1.93-1.97 (m, 1H), 1.55 (dd, 1H, J = 7.5 Hz and 12.0 Hz), 1.31-1.48 (m, 2H), 1.44 (s, 18H), 1.00 (d, 3H, J = 7.0 Hz), 0.83 (t, 3H, J = 7.3 Hz). 13 C-NMR (CDC13, 126 MHz) δ: 172.37, 156.62, 80.85, 79.04, 48.92, 45.63, 41.13, 40.18, 35.47, 28.56, 28.28, 26.49, 18.94, 16.63, 13.48. ESI-HRMS [M+H] + : (m / z) calcd for C 19 H 36 NO4: 342.2639, found: 342.2632.

[0101] Step 13: Preparation of compound II and its p-toluenesulfonic acid salt

[0102] Compound 26 (0.383 g, 1.1 mmol) was dissolved in CH2Cl2(3 mL) and CF3CO2H (2 mL) was added and stirred at room temperature until TLC monitoring showed the reaction was complete (usually 2-4 h). The reaction was concentrated on a rotary evaporator under reduced pressure to give a yellow oil. The oil was dried with a vacuum oil pump to give compound II. Compound II was dissolved in ethyl acetate (3 mL) and a solution of p-TsOH-H2O (0.26 g, 1.4 mmol) was added dropwise with an ice water bath and stirred until a white solid precipitated. The mixture was stirred at room temperature for 1 h. The mixture was filtered, the filter cake was washed with ethyl acetate (1 mL) and dried under vacuum to give the p-toluenesulfonic acid salt of compound II. White solid; 0.281 g (71%); mp 128.7 °C - 131.9 °C; 1 H-NMR (CD3OD, 500 MHz) δ: 7.71 (d, 2H, J = 8.0 Hz), 7.23 (d, 2H, J = 8.0 Hz), 3.26 (d, 1H, J = 13.0 Hz), 3.21 (d, 1H, J = 13.0 Hz), 2.49-2.69 (m, 3H), 2.37 (s, 3H), 2.10-2.14 (m, 2H), 1.52-1.60 (m, 2H), 1.40-1.45 (m, 1H), 1.05-1.08 (m, 3H), 0.88-1.91 (m, 3H). 13 C-NMR (CD3OD, 126 MHz) δ: 175.71, 143.53, 141.69, 129.82, 126.96, 48.76, 46.07, 39.02, 38.65, 36.39, 27.38, 21.30, 19.59, 16.55, 13.37. ESI-HRMS [M (free base) + H] + : (m / z) calcd for C 10 H 20 NO2: 186.1489, found: 186.1488.

[0103] Comparative Example 2

[0104] Comparative Example 2 provides a method of preparing compound III and its p-toluenesulfonic acid salt, the steps of which are as follows:

[0105]

[0106] Step 1: Preparation of compound 28

[0107] Compound 27 (80.00 g, 0.97 mol) and NBS (173.34 g, 0.97 mmol) were dissolved in CCl4(800 mL) and placed in an oil bath at 65 °C and stirred. AIBN (1.60 g, 9.7 mmol) was added in three portions at 0.5 hour intervals. After addition, the temperature was slowly increased to reflux for 2 h. If a strong exothermic reaction was observed upon the start of the reaction, the flask should be immediately immersed in an ice water bath to cool down to control the reflux. After completion, the reaction was poured into ice water. The filtrate was concentrated under reduced pressure on a rotary evaporator to give an oil, which was distilled under reduced pressure to give the target product 28. Colorless oil; 221.47 g (>100% yield due to the presence of CCl4); 78-105 °C / 40 mmHg. The product was used directly in the next step without further purification.

[0108] Step 2: Preparation of compound 29

[0109] Compound 28 (221.47 g, 1.38 mol) and quinoline (444.07 g, 3.4 mol) were added to a 1000 mL three-necked round bottom flask equipped with a thermometer on the side port and a fractionating column on the middle port. The reaction was heated to 160 °C (internal temperature). When the thermometer reached 72 °C (top temperature), the distillate was collected as the target product 29. Colorless oil; 172.00 g (>100% yield due to the presence of CCl4from the previous step); 1H-NMR (CDC13, 500 MHz) δ: 5.88-5.90 (m, 2H), 5.78-5.80 (m, 2H), 2.14-2.15 (m, 4H). 1 H-NMR (CDC13, 500 MHz) δ: 5.88-5.90 (m, 2H), 5.78-5.80 (m, 2H), 2.14-2.15 (m, 4H).

[0110] Step 3: Preparation of compound 30

[0111] Freshly distilled 29 (39.01 g, 0.49 mol) and CHCl2COCl (100.47 g, 0.68 mol) were dissolved in anhydrous n-hexane (1 L) solution. After cooling in an ice water bath with stirring, a solution of Et3N (73.91 g, 0.73 mol) in anhydrous n-hexane (200 mL) was added dropwise under N2. The addition of Et3N caused an exothermic reaction, and the addition rate should be adjusted so that the temperature of the reaction mixture was maintained at 50-55 °C. After the addition was completed, the ice water bath was removed and the reaction was stirred in an oil bath at 50 °C for 2 h, and then at room temperature overnight. The reaction mixture was poured into ice water (1 L), and the organic phase was separated. The aqueous phase was extracted with n-hexane (1 L). The combined organic phase was washed with saturated NaHCO3(200 mL) and brine, dried (MgSO4), and concentrated under reduced pressure on a rotary evaporator to give a red oil, which was distilled under reduced pressure to give the target product compound 30. Pale yellow oil; 31.70 g (34%); 80-116 °C / 5 mmHg.

[0112] Step 4: Preparation of compound 31

[0113] After the mixture of zinc powder (54.25 g, 0.83 mol) and glacial acetic acid (600 mL) was mechanically stirred in an ice-water bath, a freshly prepared solution of compound 30 (31.7 g, 0.17 mol) in glacial acetic acid (100 mL) was added dropwise under N2atmosphere. After the addition was completed, the reaction mixture was stirred in an oil bath at 55 °C overnight under N2atmosphere. TLC monitoring showed the reaction was completed, the reaction mixture was cooled to room temperature, diluted with CH2Cl2(200 mL), and filtered through celite. The filtrate was concentrated on a rotary evaporator, after removing CH2Cl2and most of the acetic acid, poured into ice water (1.5 L). Extracted with CH2Cl2(300 mL x 3), after the organic phases were combined, the organic phase was washed with saturated NaHCO3until the pH of the aqueous phase reached > 7, washed with saturated brine (300 mL), dried (MgSO4), concentrated under reduced pressure on a rotary evaporator to give a brown oil, which was distilled under reduced pressure to give the target product compound 31. Pink oil; 13.56 g (65%); 80-104 °C / 40 mmHg. 1 H-NMR (CDC13, 500 MHz) δ: 5.93-5.96 (m, 1H), 5.85-5.88 (m, 1H), 3.55-3.58 (m, 1H), 3.27 (ddd, 1H, J = 3.0 Hz, 9.5 Hz and 17.0 Hz), 2.91-2.96 (m, 1H), 2.57-2.62 (m, 1H), 1.97-2.05 (m, 3H), 1.53-1.60 (m, 1H).

[0114] Step 5: Preparation of compound 32

[0115] Under N2atmosphere and ice-water bath, t-BuOK (24.91 g, 0.22 mol) was added to anhydrous THF (200 mL) to form a suspension, and a solution of diethylphosphoryl tert-butyl acetate (55.99 g, 0.22 mol) in anhydrous THF (150 mL) was added dropwise. After the addition was completed, the stirring was continued in the ice-water bath for 1 hour, then a solution of compound 31 (13.56 g, 0.11 mol) in anhydrous tetrahydrofuran (50 mL) was added dropwise. After the addition was completed, the stirring was continued at room temperature, TLC showed the reaction was completed, poured into ice water (1 L), extracted with CH2Cl2(300 mL x 3), and washed with 1 M hydrochloric acid (100 mL) and brine in turn, dried (MgSO4), concentrated under reduced pressure on a rotary evaporator to give the crude compound 32 as a light yellow oil compound (about 57.18 g).

[0116] Step 6: Preparation of compound 33

[0117] The above crude compound 32 (24.45 g, 0.11 mol) was added to a solution of CH3NO2(220 mL) and DBU (33.80 g, 0.22 mol) and heated on an oil bath at 80 °C overnight. TLC monitoring showed that the reaction was complete. After the reaction mixture was cooled to room temperature, it was poured into 1 L of ice water and extracted with CH2Cl2(300 mL x 3). The organic phases were combined and washed with 1 M hydrochloric acid (200 mL) and brine successively, dried (MgSO4), and concentrated under reduced pressure on a rotary evaporator to give a dark red oil of crude product, which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target product compound 33. Light yellow oil; 11.99 g (total yield of compound 31 to compound 33 was 91%); 1 H-NMR (CDC13, 500 MHz) δ: 5.83-5.87 (m, 1H), 5.66-5.69 (m, 1H), 4.92 (d, 1H, J = 11.5 Hz), 4.77 (d, 1H, J = 11.5 Hz), 2.81-2.87 (m, 1H), 2.58 (s, 2H), 2.38-2.43 (m, 1H), 2.25-2.29 (m, 1H), 2.02-2.08 (m, 1H), 1.85-1.92 (m, 1H), 1.74-1.83 (m, 1H), 1.62-1.70 (m, 1H), 1.45 (s, 9H). 13 C-NMR (CDC13, 126 MHz) δ: 170.77, 129.26, 128.71, 81.13, 81.02, 40.18, 39.66, 37.73, 36.42, 28.88, 28.21, 22.60, 21.95. ESI-HRMS [M+H] + :(m / z) calcd for C 15 H 24 NO4: 282.1700, found: 282.1693.

[0118] Step 7: Preparation of compound 34

[0119] Compound 33 (10.74 g, 38 mmol), iron powder (15.99 g, 0.29 mol) and NH4CI (6.12 g, 0.11 mol) were added successively into a solution of 95% EtOH / H2O (150 mL, v / v = 2 / 1) and stirred under reflux overnight in N2environment. The reaction was monitored by TLC. After the reaction solution was cooled to room temperature, it was filtered with celite and the filtrate was concentrated on a rotary evaporator to remove ethanol, and then solid was precipitated. The solid was dissolved in ethyl acetate (200 mL) and water (100 mL), shaken, and the organic phase was separated. The aqueous phase was extracted with ethyl acetate (200 mL x 2). The combined organic phase was washed with brine, dried (MgS04), and concentrated on a rotary evaporator under reduced pressure to give compound 34 (free base) as a yellow oil. A small amount of p-TsOH-H2O (7.26 g, 38 mmol) in ethyl acetate was added dropwise to a solution of crude compound 34 (free base) in ethyl acetate (100 mL) with stirring. White solid was precipitated, and the mixture was stirred for another 1 h, filtered, and the filter cake was washed with ethyl acetate (20 mL) and dried under vacuum to give the target product, compound 34 p-toluenesulfonate. White solid; 14.50 g (90%); melting point 169.8 °C-173.1 °C; 1 H-NMR (DMSO-d6, 500 MHz) δ: 7.76 (br s, 3H), 7.49 (d, 2H, J = 7.0 Hz), 7.12 (d, 2H, J = 7.5 Hz), 5.79-5.82 (m, 1H), 5.62-5.65 (m, 1H), 3.37-3.39 (m, 1H), 3.23-3.27 (m, 1H), 3.11-3.15 (m, 1H), 2.74-2.76 (m, 1H), 2.486-2.490 (m, 1H), 2.29 (s, 3H), 2.18-2.24 (m, 1H), 2.05-2.10 (m, 1H), 1.96-2.01 (m, 1H), 1.74-1.80 (m, 1H), 1.57-1.66 (m, 3H), 1.39 (s, 9H). 13 C-NMR (DMSO-d6, 126 MHz) δ: 170.45, 145.46, 137.82, 129.61, 128.13, 128.03, 125.51, 80.19, 44.57, 38.50, 38.06, 36.99, 35.43, 28.09, 27.77, 22.13, 21.41, 20.80. ESI-HRMS [M (free base) + H] + :(m / z) calcd. for C 15 H 26 NO2: 252.1958, found: 252.1953.

[0120] Step 8: Preparation of compound 35

[0121] The p-toluenesulfonic acid salt of compound 34 (14.50 g, 34 mmol) was added to a mixture of saturated NaHC03(200 mL) and ethyl acetate (150 mL) and stirred for 10 min. The organic phase was separated and the aqueous phase was extracted with ethyl acetate (150 mL x 2). The combined organic phase was washed with brine, dried (MgS04) and concentrated on a rotary evaporator to give compound 34 (free base) as a light yellow oil. The free base compound 34 was dissolved in anhydrous tetrahydrofuran (80 mL) under an ice-water bath, and a solution of Et3N (11.59 g, 0.11 mol) and Boc20 (12.50 g, 57 mmol) in anhydrous tetrahydrofuran (20 mL) was added dropwise. After the addition was completed, the ice-water bath was removed and the mixture was stirred at room temperature overnight. TLC monitoring showed that the reaction was completed, and the mixture was poured into 300 mL of ice-water and extracted with ethyl acetate (200 mL x 2), washed with 1 M hydrochloric acid (50 mL) and brine successively, dried (MgS04) and concentrated on a rotary evaporator under reduced pressure. The residue was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target product compound 35 as a white solid. Light yellow oil; 1.90 g (16%); 1 H-NMR (DMSO-d6, 500 MHz) δ: 6.81 (t, 1H, J = 6.3 Hz), 5.75-5.79 (m, 1H), 5.62-5.65 (m, 1H), 3.33 (dd, 1H, J = 7.0 Hz and 13.8 Hz), 3.23 (dd, 1H, J = 6.3 Hz and 13.8 Hz), 2.64-2.69 (m, 1H), 2.29 (d, 1H, J = 16.5 Hz), 2.25 (d, 1H, J = 16.5 Hz), 2.10-2.15 (m, 1H), 1.93-2.02 (m, 2H), 1.73-1.80 (m, 1H), 1.62-1.68 (m, 1H), 1.50-1.58 (m, 2H), 1.383 (s, 9H), 1.375 (s, 9H). 13 C-NMR (DMSO-d6, 126 MHz) δ: 170.57, 156.21, 130.27, 127.76, 79.16, 77.13, 54.90, 45.58, 38.50, 37.79, 35.78, 28.62, 28.24, 27.78, 22.36, 21.85. ESI-HRMS [M+H] + :(m / z) calcd. for C 20 H 34NO 4: 352.2482, found: 352.2477.

[0122] Step 9: Preparation of compound 36

[0123] Compound 35 (2.50 g, 7.1 mmol) was dissolved in t-BuOH (25 mL) and deionized water (12 mL) was added with stirring under ice water bath. Then KMnO4(1.57 g, 9.9 mmol) / NaOH (0.36 g, 9.0 mmol) solution prepared with a small amount of water was added dropwise. After the addition was completed, the reaction was stirred at room temperature for 30 minutes. TLC monitoring showed that the reaction was completed. The reaction was quenched by dropwise addition of 10% Na2S2O3 aqueous solution until the excess KMnO4was completely consumed and the purple solution faded. The resulting mixture was filtered through celite and the filtrate was concentrated under reduced pressure on a rotary evaporator to remove t-BuOH. The solution was adjusted to pH 7 with 1 M HCl and extracted with CH2Cl2(100 mL x 3). The combined organic phase was dried (MgSO4) and the filtrate was concentrated under reduced pressure on a rotary evaporator to give a yellow oil. The target product compound 36 was obtained by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 9 ~ 1 / 1] with preliminary purification. Yellow oil; 0.53 g.

[0124] Step 10: Preparation of compound 37

[0125] Compound 36 (0.53 g, 1.3 mmol) was dissolved in anhydrous tetrahydrofuran (12 mL) and deionized water (3 mL) was added with stirring under ice water. Then NaIO4(0.59 g, 2.8 mmol) was added portionwise. After the addition was completed, the reaction was stirred at room temperature for 30 minutes. TLC monitoring showed that the reaction was completed and the excess NaIO4was consumed by the addition of Na2S2O3 aqueous solution. The reaction was extracted with ethyl acetate (70 mL x 3) and the combined organic phase was washed with brine and dried (MgSO4). The crude compound 37 (0.56 g) was obtained as a yellow oil after concentration under reduced pressure on a rotary evaporator. It was used directly in the next step without purification.

[0126] Step 11: Preparation of compound 38

[0127] To a solution of compound 37 (0.56 g, 1.5 mmol) in 95% EtOH (15 mL) was added NaBH4(0.17 g, 4.5 mmol) portion wise under ice water bath. After the addition was completed, the reaction mixture was stirred at room temperature for 30 min. TLC monitoring showed the reaction was completed. The reaction mixture was poured into ice water (50 mL) and extracted with ethyl acetate (50 mL x 3). The combined organic phase was washed with brine and dried over (MgSO4). The solvent was removed under reduced pressure on a rotary evaporator to give a yellow oil. The product was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 9 ~ 1 / 1] to give the target product compound 38. Yellow oil. 0.15 g (5% overall yield from compound 35 to compound 38); 1 H-NMR (CDC13, 500 MHz) δ: 5.17 (t, 1H, J = 6.5 Hz), 3.75-3.78 (m, 1H), 3.56-3.62 (m, 3H), 3.40-3.45 (m, 3H), 3.16-3.20 (m, 1H), 2.56-2.61 (m, 1H), 2.43 (d, 1H, J = 14.0 Hz), 2.34-2.44 (m, 1H), 2.28 (d, 1H, J = 14.0 Hz), 1.86-1.90 (m, 1H), 1.61-1.71 (m, 1H), 1.41-1.50 (m, 21H). 13 C-NMR (CDC13, 126 MHz) δ: 172.15, 156.69, 81.01, 79.22, 63.37, 62.15, 48.65, 42.58, 40.93, 39.44, 34.10, 31.45, 30.05, 28.43, 28.14, 21.92. ESI-HRMS [M+H] + :(m / z) calcd for C 20 H 38 NO6: 388.2694, found: 388.2690.

[0128] Step 12: Preparation of compound 39

[0129] I2(0.65 g, 2.6 mmol) was dissolved in anhydrous CH2Cl2(7 mL) under N2and ice water bath. PPh3(0.67 g, 2.6 mmol) was added portionwise. After addition, the reaction mixture was stirred for 30 min. Imidazole (0.52 g, 7.6 mmol) was added portionwise. After addition, the reaction mixture was stirred for another 30 min, then a solution of compound 38 (0.33 g, 0.85 mmol) in CH2Cl2(3 mL) was added dropwise. After the addition was completed, the reaction mixture was transferred to room temperature and stirred overnight. TLC monitoring showed the reaction was completed, 10% Na2S2O3 aqueous solution was added to quench the reaction. Extraction with CH2Cl2(50 mL x 3), the organic phase was combined and washed with brine, dried (MgSO4), concentrated under reduced pressure on a rotary evaporator to give a milky white sticky material, purified by column chromatography [V(EtOAc) / V(n-hexane) = 5 / 95] to give the target product compound 39. Pale yellow oil; 0.26 g (50%);1H-NMR (CDCI3, 500 MHz) δ: 4.99 (br s, 1H), 3.44-3.48 (m, 1H), 3.32 (dd, 1H, J = 6.0 Hz and 9.0 Hz), 3.13-3.20 (m, 4H), 2.80-2.89 (m, 1H), 2.27-2.37 (m, 3H), 1.99-2.03 (m, 1H), 1.70-1.76 (m, 2H), 1.61-1.67 (m, 2H), 1.53-1.58 (m, 1H), 1.46 (s, 9H), 1.44 (s, 9H). 1 H-NMR (CDCI3, 500 MHz) δ: 4.99 (br s, 1H), 3.44-3.48 (m, 1H), 3.32 (dd, 1H, J = 6.0 Hz and 9.0 Hz), 3.13-3.20 (m, 4H), 2.80-2.89 (m, 1H), 2.27-2.37 (m, 3H), 1.99-2.03 (m, 1H), 1.70-1.76 (m, 2H), 1.61-1.67 (m, 2H), 1.53-1.58 (m, 1H), 1.46 (s, 9H), 1.44 (s, 9H). 13 C-NMR (CDCI3, 126 MHz) δ: 171.52, 156.59, 81.38, 79.45, 53.57, 48.20, 43.18, 39.89, 36.13, 35.80, 32.63, 28.55, 28.29, 26.76, 9.73, 6.62. ESI-HRMS [M+H] + :(m / z) calcd for C 20 H 36 I2NO4: 608.0728, found: 608.0721.

[0130] Step 13: Preparation of compound 40

[0131] Compound 39 (0.26 g, 0.43 mmol), 10% Pd / C (0.10 g) and Et3N (0.13 g, 1.3 mmol) were added sequentially to MeOH (10 mL), the reaction vessel was purged with hydrogen gas (balloon) and placed on a stirrer bar at room temperature and stirred overnight. TLC monitoring showed the reaction to be complete in 12 h. The reaction mixture was filtered through celite and the filtrate was concentrated on a rotary evaporator under reduced pressure to give an oily residue which was diluted with ethyl acetate (50 mL). The resulting solution was washed sequentially with 1 M hydrochloric acid and brine, dried (MgS04) and concentrated on a rotary evaporator under reduced pressure to give a pale yellow oil which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target compound 40. Pale yellow oil; 0.15 g (98%);1H-NMR (CDC13, 500 MHz) δ: 4.99 (br s, 1H), 3.41 (dd, 1H, J = 7.5 Hz and 14.0 Hz), 3.18 (dd, 1H, J = 5.5 Hz and 14.0 Hz), 2.46-2.53 (m, 1H), 2.38 (d, 1H, J = 13.5 Hz), 2.26 (d, 1H, J = 14.0 Hz), 2.16-2.21 (m, 1H), 1.93-1.97 (m, 1H), 1.55 (dd, 1H, J = 7.5 Hz and 12.0 Hz), 1.44 (s, 9H), 1.43 (s, 9H), 1.32-1.38 (m, 1H), 1.19-1.31 (m, 2H), 1.12-1.18 (m, 2H), 0.99 (d, 3H. J = 7.5 Hz), 0.88 (t, 3H, J = 7.0 Hz). 1 H-NMR (CDC13, 500 MHz) δ: 4.99 (br s, 1H), 3.41 (dd, 1H, J = 7.5 Hz and 14.0 Hz), 3.18 (dd, 1H, J = 5.5 Hz and 14.0 Hz), 2.46-2.53 (m, 1H), 2.38 (d, 1H, J = 13.5 Hz), 2.26 (d, 1H, J = 14.0 Hz), 2.16-2.21 (m, 1H), 1.93-1.97 (m, 1H), 1.55 (dd, 1H, J = 7.5 Hz and 12.0 Hz), 1.44 (s, 9H), 1.43 (s, 9H), 1.32-1.38 (m, 1H), 1.19-1.31 (m, 2H), 1.12-1.18 (m, 2H), 0.99 (d, 3H. J = 7.5 Hz), 0.88 (t, 3H, J = 7.0 Hz). 13 C-NMR (CDC13, 126 MHz) δ: 172.38, 156.59, 80.84, 79.02, 48.92, 43.44, 41.14, 40.26, 35.54, 28.55, 28.42, 28.27, 26.56, 22.06, 16.74, 14.57. ESI-HRMS [M+H] + :(m / z) calcd for C 20 H 38 NO4: 356.2795, found: 356.2790.

[0132] Step 14: Preparation of compound III and its p-toluenesulfonic acid salt

[0133] Compound 40 (0.10 g, 0.28 mmol) was dissolved in CH2Cl2(3 mL) and CF3CO2H (2 mL) was added and stirred at room temperature until TLC monitoring showed the reaction was complete (usually 2-4 h). The reaction was concentrated on a rotary evaporator under reduced pressure to give a yellow oil. The oil was dried on a vacuum oil pump to give compound III. Compound III was dissolved in ethyl acetate (2 mL) and a solution of p-TsOH-H2O (0.064 g, 0.34 mmol) was added dropwise with an ice water bath, using the minimum amount of ethyl acetate to dissolve, and stirred until a white solid precipitated. Stirred at room temperature for 1 h. Filtered, the filter cake was washed with ethyl acetate (1 ml) and dried under vacuum to give compound III as the p-toluenesulfonic acid salt. White solid; 0.10 g (96%); mp 135.9 °C - 142.0 °C; 1 H-NMR (CD3OD, 500 MHz) δ: 7.70 (d, 2H, J = 8.5 Hz), 7.23 (d, 2H, J = 8.0 Hz), 3.26 (d, 1H, J = 13.0 Hz), 3.20 (d, 1H, J = 13.0 Hz), 2.66 (d, 1H, J = 17.0 Hz), 2.58 (d, 1H, J = 17.0 Hz), 2.50-2.59 (m, 1H), 2.37 (s, 3H), 2.17-2.22 (m, 1H), 2.10-2.14 (m, 1H), 1.50-1.56 (m, 2H), 1.27-1.39 (m, 2H), 1.61-1.24 (m, 1H), 1.05 (d, 3H, J = 7.5 Hz), 0.93 (t, 3H, J = 7.0 Hz). 13 C-NMR (D2O, 126 MHz) δ: 176.68, 142.47, 139.34, 129.41, 125.32, 47.45, 42.34, 38.00, 37.38, 34.76, 27.41, 25.91, 21.18, 20.44, 15.55, 13.50. ESI-HRMS [M (free base) + H] + :(m / z) calcd. for C 11 H 22 NO2: 200.1645, found: 200.1646.

[0134] Comparative Example 3

[0135] Comparative Example 3 provides a method of preparing compound IV, the steps of which are as follows:

[0136]

[0137] Step 1: Preparation of compound 42

[0138] To a stirred suspension of t-BuOK (32.02 g, 0.29 mol) in anhydrous THF (400 mL) was added dropwise a solution of diethylphosphoryl tert-butyl acetate (71.98 g, 0.29 mol) in anhydrous THF (200 mL) under N2atmosphere and ice-water bath. After the addition was completed, the stirring was continued in the ice-water bath for 1 h, then a solution of compound 41 (10.00 g, 0.14 mol) in anhydrous THF (50 mL) was added dropwise. After the addition was completed, the stirring was continued at room temperature, TLC showed the reaction was completed, poured into ice-water (1 L), extracted with CH2Cl2(300 mL x 3), washed with 1 M hydrochloric acid (100 mL) and brine successively, dried (MgSO4), concentrated on a rotary evaporator under reduced pressure to give crude 42. It was used directly for the next step without purification.

[0139] Step 2: Preparation of compound 43

[0140] The above crude compound 42 (24.00 g, based on 0.14 mol) was added to a solution of CH3NO2(240 mL), then DBU (43.44 g, 0.29 mol) was added, heated on an oil bath at 80 °C overnight, TLC monitoring showed the reaction was completed. After the reaction mixture was cooled to room temperature, poured into 1 L ice-water, extracted with CH2Cl2(300 mL x 3). The organic phases were combined and washed with 1 M hydrochloric acid (200 mL) and brine successively, dried (MgSO4), concentrated on a rotary evaporator under reduced pressure to give a dark red oil crude, purified by column chromatography [V(EtOAc) / V(n-hexane) = 1 / 99] to give the target product 43. 20.00 g (the total yield of steps 41 to 43 was 62%); 1 H-NMR (CDCI3, 500 MHz) δ: 4.69 (s, 2H), 2.61 (s, 2H), 2.08-2.16 (m, 2H), 1.96-2.06 (m, 4H), 1.46 (s, 9H). 13 C-NMR (CDCI3, 126 MHz) δ: 170.46, 81.39, 81.26, 41.79, 39.80, 30.42, 28.25, 15.46. ESI-HRMS [M+H] + :(m / z) calcd for C 11 H 20 NO4: 230.1387, found: 230.1386.

[0141] Step 3: Preparation of compound 44

[0142] Compound 43 (3.00 g, 13 mmol) was dissolved in CH2Cl2(30 mL) at room temperature, and CF3CO2H (15 mL) was added dropwise. The reaction was stirred until TLC monitoring showed that the reaction was complete (usually within 3-4 hours). Concentration under reduced pressure on a rotary evaporator gave a yellow oil, which was purified by column chromatography [V(EtOAc) / V(n-hexane) = 6 / 4] to give the target compound 44. Pale yellow oil; 2.05 g (91%);1H-NMR (DMSO-d6, 500 MHz) δ: 4.77 (s, 2H), 2.57 (s, 2H), 2.01-2.07 (m, 2H), 1.88-1.97 (m, 4H). 1 H-NMR (DMSO-d6, 500 MHz) δ: 4.77 (s, 2H), 2.57 (s, 2H), 2.01-2.07 (m, 2H), 1.88-1.97 (m, 4H). 13 C-NMR (CDC13, 126 MHz) δ: 176.02, 81.10, 40.10, 39.32, 30.43, 15.42. ESI-HRMS [M + Na] : + : (m / z) calcd for C7H 11 NNaO4: 196.0580, found: 196.0577.

[0143] Step 4: Preparation of compound IV

[0144] Compound 44 (2.05 g, 12 mmol) and 10% Pd / C (0.2 g) were added successively to MeOH (10 mL), and the reaction vessel was replaced with hydrogen gas (balloon) and stirred at room temperature overnight according to standard procedures. TLC monitoring showed that the reaction was complete (usually within 12 hours). The reaction mixture was filtered through celite, and the filtrate was concentrated under reduced pressure on a rotary evaporator to give a solid. Purification by trituration [V(EtOAc) / V(n-hexane) = 1 / 0] gave the target compound IV. White solid; 0.871 g (51%); m.p. 169.2 °C - 172.4 °C; 1 H-NMR (DMSO-d6, 500 MHz) δ: 4.77 (s, 2H), 2.57 (s, 2H), 2.01-2.07 (m, 2H), 1.88-1.97 (m, 4H). 13 C-NMR (D2O, 126 MHz) δ: 180.49, 47.31, 46.54, 37.85, 29.54, 14.48. ESI-HRMS [M + H] + : (m / z) calcd for C7H 14 NO2: 144.1019, found: 144.1017.

[0145] Comparative Examples 4-7

[0146] The compounds of the following table were synthesized according to the preparation method of Reference Example 1 and Comparative Examples 1 to 3:

[0147] Table 1

[0148]

[0149] Performance test

[0150] In vitro binding of the examples and comparative examples to human recombinant calcium channel Cav2.2 / β3 / α2δ-1

[0151] There are four subtypes of voltage-gated calcium channel α2δ subunit, α2δ-1, α2δ-2, α2δ-3 and α2δ-4, among which α2δ-1 is the subtype mediating chronic neuropathic pain (Field, M. J.; et al. Proc. Natl. Acad. Sci. U. S. A. 2006, 103, 17537-17542), so the binding strength of a compound to α2δ-1 is a direct indicator of its analgesic effect on chronic neuropathic pain (Calandre, E. P.; et al. Expert Rev. Neurother. 2016, 16, 1263-1277).

[0152] The strength of the binding of the compounds of the present application to human recombinant calcium channel Cav2.2 / β3 / α2δ-1 in vitro is basically operated according to the method that has been reported (Gee, N. S.; et al. J. Biol. Chem. 1996, 271, 5768-5776; Marais, E.; et al. Mol. Pharmacol. 2001, 59, 1243-1248.). The test uses CHO cells expressing human recombinant calcium channel Cav2.2 / β3 / α2δ-1, after the cell membrane is separated according to the routine, 3 μg of cell membrane is added to each well, the modified HEPES / KOH buffer (pH 7.4) is used as the solution of the test system, and then 5 nM of [ 3 H] gabapentin and 6 concentrations of the test compound (3, 9, 27, 81, 243 and 729 nM) are added, and the test system is incubated at 25 °C for 120 min. The non-specific binding is obtained by replacing the test compound in the above test system with 10 μM gabapentin. After the incubation is completed, the cell membrane is collected by filtration and washed with 50 mM Tris-HCl (pH 7.4), and then the radioactivity of the [ 3 H] gabapentin bound on the cell membrane is tested by liquid scintillation technology. The compounds of the present application compete with [ 3 H] gabapentin for the binding to human recombinant calcium channel Cav2.2 / β3 / α2δ-1, and the compounds of the present application have a Ki value of less than 10 μM. 3The inhibition rate of gabapentin binding to recombinant human calcium channel Cav2.2 / β3 / α2δ-1 was calculated using the following formula:

[0153] Inhibition rate = [(II U ) / (I0-I U )]×100%

[0154] in,

[0155] I is the compound to be tested and [ 3 The radioactivity corresponding to the simultaneous co-incubation of H]gabapentin with human recombinant calcium ion channel Cav2.2 / β3 / α2δ-1.

[0156] I0 is [ 3 The radioactivity corresponding to [H] gabapentin co-incubated with human recombinant calcium ion channel Cav2.2 / β3 / α2δ-1, without the analyte compound added to the incubation system.

[0157] I U It is 10μM gabapentin and [ 3 The radioactivity corresponding to the simultaneous co-incubation of H]gabapentin with human recombinant calcium ion channel Cav2.2 / β3 / α2δ-1.

[0158] The test compound inhibited 50% of [ 3 The concentration of gabapentin in recombinant human calcium channel Cav2.2 / β3 / α2δ-1 was defined as IC50. 50 IC 50 The inhibition rate described above is calculated using nonlinear least squares regression analysis (MathIQ). TM IDBusiness Solutions Ltd., UK). Test results are shown in Table 2:

[0159] Compound IC 50 (nM) Compound IC 50 (nM) Example 1 15.2 Compound E 283 Comparative Example 1 170 Compound F 167 Comparative Example 2 390 Compound G 307 Comparative Example 3 250 Compound H >729 Comparative Example 4 93.4 Compound J 144 Comparative Example 5 119 Compound K 193 Comparative Example 6 190 Compound L 234 Comparative Example 7 276 Compound M 212 Compound A 321 Compound N >729 Compound B 387 Compound O 173 Compound C 108 Compound P 242 Compound D 197 / /

[0160] The following compounds were prepared according to documents US6635673, US20030199567 and US20030212133, and were used to test in vitro activity together with the compounds of the present invention.

[0161]

[0162] As can be seen from the activity data of this embodiment, the activity of the compound of formula I of the present invention is significantly superior to that of similar structures, including preferred specific representative compounds in documents US6635673, US20030199567 and US20030212133, indicating that the two ethyl groups in the compound of formula I are extremely important for the activity and can be used to prepare drugs for treating chronic neuropathic pain, epilepsy and anxiety.

[0163] Gamma-aminobutyric acid drugs acting on voltage-gated calcium channel alpha2delta-1 ligands such as gabapentin, pregabalin and the like have analgesic effect on chronic neuropathic pain, and have anti-epileptic (pregabalin, approved by FDA in the United States) and anti-anxiety (pregabalin, approved by EMA in Europe) effects, which are related to the combination of the drugs and voltage-gated calcium channel alpha2delta-1 ligands. Therefore, the compound of formula I in the present application can also be used for preparing drugs for treating epilepsy and anxiety.

[0164] The above is a detailed description in combination with the embodiments of the present application, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge possessed by those skilled in the art without departing from the purpose of the present application.

Claims

1. A γ-aminobutyric acid derivative or a pharmaceutically acceptable salt thereof, characterized by, The structural formula of the γ-aminobutyric acid derivative is a compound as shown in Formula Ia: Formula Ia.

2. A pharmaceutical composition, characterized by, The pharmaceutical composition comprises a pharmaceutically active component and a pharmaceutically acceptable excipient, wherein the pharmaceutically active component comprises the γ-aminobutyric acid derivative or the pharmaceutically acceptable salt thereof according to claim 1.

3. The pharmaceutical composition of claim 2, wherein, The pharmaceutically active component accounts for 5% to 50% of the total mass of the pharmaceutical composition.

4. The pharmaceutical composition of claim 2, wherein, The pharmaceutically acceptable excipient comprises at least one of a solvent, an excipient, a diluent, a binder, a disintegrant, a dispersant, a flavoring agent, a suspending agent, a surfactant, an isotonic agent, a thickening agent, an emulsifying agent, a preservative, a glidant or a lubricant.

5. The pharmaceutical composition of claim 2, wherein, The dosage form of the pharmaceutical composition is at least one of a solid oral preparation, a liquid oral preparation or an injection.

6. The pharmaceutical composition of claim 5, wherein, The solid oral preparation comprises at least one of a dispersible tablet, an enteric-coated tablet, a chewable tablet, a disintegrating tablet, a capsule or a granule.

7. Use of the γ-aminobutyric acid derivative or the pharmaceutically acceptable salt thereof according to claim 1; or the pharmaceutical composition according to any one of claims 2 to 6 in the preparation of a medicament for treating chronic neuropathic pain.

8. Use of the γ-aminobutyric acid derivative or the pharmaceutically acceptable salt thereof according to claim 1; or the pharmaceutical composition according to any one of claims 2 to 6 in the preparation of a medicament for treating epilepsy.

9. Use of the γ-aminobutyric acid derivative or the pharmaceutically acceptable salt thereof according to claim 1; or the pharmaceutical composition according to any one of claims 2 to 6 in the preparation of a medicament for treating anxiety.

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