Ester bond compound, preparation method and application thereof, and analgesic drug

Abstract

The present invention relates to the field of medicine, and provides an ester bond compound and a preparation method and application thereof, and an analgesic drug. The structural formula of the ester bond compound provided by the present invention is shown in Formula I. Compared with the best analgesic combination "sinomenine + pregabalin" found in this laboratory, the ester bond compound provided by the present invention has a longer effective time and a stronger analgesic effect. At half the molar amount, it has a stronger analgesic effect, faster onset, longer analgesic time, and less fluctuation in efficacy than pregabalin, a first-line drug for treating pain; and the ester bond compound provided by the present invention can produce a stronger analgesic effect in vivo, and can reduce the occurrence of drug side effects by less dosage. In summary, the ester bond compound provided by the present invention can effectively control the development of the disease, improve the quality of life of patients, and has broad application prospects in pain treatment.

Description

Technical Field

[0001] The present invention relates to the medical field, and in particular to an ester bond compound, a preparation method and application thereof, and an analgesic drug. Background Art

[0002] Chronic pain refers to pain that lasts for more than one month. Common chronic pain includes chronic back pain, fibromyalgia, chronic arthritis pain, and various neuropathic pain. Lu You, who wrote "My head hurts so much that my teeth are shaking, and the doctor cannot stop me from writing letters," and American singer Lady Gaga, who suffers from fibromyalgia syndrome, are both victims of chronic pain. Chronic pain has the following characteristics.

[0003] First, the incidence of chronic pain is high and the patients are widely distributed. The two main causes of chronic pain are neuropathic damage and acute pain solidification caused by surgery (depending on the type of surgery, 10% to 50% of postoperative pain will develop into chronic pain). Anyone may suffer from chronic pain due to different factors such as disease, trauma or surgery. In my country, the incidence of chronic pain remains high, and about 400 million people have a need for treatment for chronic pain, but 80% of chronic pain patients have not yet received adequate treatment.

[0004] Second, chronic pain seriously endangers the physical and mental health of patients. With the continuous deepening of research on chronic pain, people have found that chronic pain is the common result of the interaction of multiple systems in the human body and the interaction with the environment. Its occurrence process involves multiple functional areas of the brain; multiple bidirectional pathways in the central nervous system; and external factors such as emotions, cognition and environment. First, chronic pain will limit the mobility of the body parts related to the lesion, and limit the patient's daily activities such as eating, sleeping, and exercise, so that many patients completely lose their ability to work. Secondly, long-term, severe, and unexpected pain is often likened to an immortal cancer, which significantly reduces the patient's quality of life and greatly destroys the patient's mental health. Studies have shown that 15% of chronic headache patients suffer from severe depression, which is much higher than the 5% of healthy people. Suffering from chronic pain increases the risk of suicide. 5-14% of chronic pain patients attempt suicide, which is almost twice that of healthy people.

[0005] Third, chronic pain is a huge challenge to the public health system. A 2011 study showed that about 120 million Americans suffering from chronic pain caused economic losses of 560 billion to 635 billion U.S. dollars to the entire society. The socioeconomic cost of chronic pain is greater than heart disease (309 billion U.S. dollars), cancer (244 billion U.S. dollars) and diabetes (188 billion U.S. dollars). Therefore, chronic pain should be regarded as a chronic disease with the same importance as heart disease, cancer and diabetes. With the continuous acceleration of my country's urbanization process, the change of people's living habits, and the acceleration of the aging process of the population, chronic pain and other chronic diseases have gradually attracted more and more attention. In 2007, Document No. 227 of the Ministry of Health and Medical Affairs clearly established a pain department, stipulating that its main business scope is the diagnosis and treatment of chronic pain; more and more chronic pain patients have received treatment and their lives have improved. However, we must be aware that my country has a huge population base, the incidence of chronic pain in my country is also on the rise, and we are also facing the dilemma of lack of effective intervention drugs.

[0006] Chronic pain is complex, long-term and resistant to treatment. Currently, the drugs available for the treatment of chronic pain are generally ineffective, and the lack of effective treatments for patients with chronic pain has become a social problem that needs to be addressed urgently.

[0007] Anti-epileptic GABA drugs such as gabapentin and pregabalin are the first choice for treating chronic pain. However, the therapeutic effect of gabapentin and pregabalin on chronic pain is limited: according to international literature, for traumatic nerve injury, less than 50% of patients can have moderate pain relief; for mixed neuralgia, only 21% of patients are effective; for herpes zoster neuralgia, only 32-34% of patients are effective. In recent years, reports on adverse reactions of gabapentin and pregabalin have increased year by year, which has attracted people's attention. The main adverse reactions include: sedation, cognitive dullness, dizziness, drowsiness (20%-30% of patients taking the drug) and weight gain (1 / 6 of patients gain more than 7% weight after taking the drug for one year). The side effects of GABA drugs are positively correlated with the dose.

[0008] Tricyclic antidepressants can block the reuptake of norepinephrine (NA) and 5-hydroxytryptamine (5-HT) by nerve endings, but their analgesic mechanism is unclear; although the efficacy for chronic pain is about 40%, tricyclic antidepressants usually have only mild effects and slow onset, requiring at least 1 to 2 weeks of medication to take effect. Common adverse reactions of tricyclic antidepressants include: sedation, mild cognitive impairment, blurred vision, dry mouth, tachycardia, orthostatic hypotension, delayed urination, constipation and weight gain.

[0009] Although opioids can achieve strong analgesic effects, they are prone to tolerance and dependence. Continuous use of opioids after dependence is formed may cause a vicious cycle and lead to addiction, causing huge changes in the patient's mood. Doctors have different opinions on when to prescribe such drugs to patients. Currently, more than 8 million Americans regularly use opioid painkillers, and 2 million are dependent on opioids. The abuse of highly addictive painkillers such as opioids has become a stubborn disease plaguing American society.

[0010] According to the latest data from the NIH, there are currently a total of 2,488 clinical trials worldwide for chronic pain (2020, clinical trial.org). Unfortunately, of the 59 new drugs and therapies approved by the US FDA in 2018, none were for chronic pain. Between 2005 and 2009, only a few products for arthritis and fibromyalgia were approved by the FDA. These drugs are either modifications of existing drugs (pregabalin, duloxetine, etc.) or new dosage forms of existing drugs (various types of sustained-release opioid analgesics). There is a lack of truly "new" compounds and "new" targets. Although a variety of natural compounds in the preclinical stage are discovered every year, their analgesic effects are generally insufficient and they cannot pass safety and efficacy evaluations. The real shortage of painkillers still plagues every chronic pain patient.

[0011] In summary, in order to effectively control the development of the disease and improve the quality of life of patients, it is imperative to find and develop safe and effective analgesics. Summary of the invention

[0012] In view of this, the present invention provides an ester bond compound and its preparation method and application, and analgesic medicine. The ester bond compound provided by the present invention is a brand-new compound with strong analgesic effect, rapid onset, long analgesic time, small fluctuation of drug effect, and high bioavailability, and can reduce the occurrence of drug side effects by less administration dosage.

[0013] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0014] An ester bond compound, the structural formula of which is shown in Formula I:

[0015]

[0016] The present invention also provides a method for preparing the ester bond compound described in the above scheme, comprising the following steps:

[0017] A compound having a structure shown in Formula II, a solvent, a base and Boc anhydride are mixed to carry out an amino protection reaction to obtain a compound having a structure shown in Formula III:

[0018] In formula III, R is -Boc;

[0019] The compound having the structure shown in Formula III, the compound having the structure shown in Formula IV, a condensing agent and a solvent are mixed to carry out a condensation reaction to obtain a compound having the structure shown in Formula V;

[0020] In Formula V, R is -Boc;

[0021] The compound having the structure shown in Formula V, a solvent and a deprotection agent are mixed to carry out a deprotection group reaction to obtain an ester bond compound having the structure shown in Formula I.

[0022] Preferably, the base is sodium hydroxide; the molar ratio of the compound having the structure shown in Formula II to the base is 1:1-1.5; the molar ratio of the compound having the structure shown in Formula II to Boc anhydride is 1:1-1.5; the temperature of the amino protection reaction is 20-25°C, and the time is 1-1.5h.

[0023] Preferably, the condensing agent is 4-dimethylaminopyridine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N,N-diisopropylethylamine; the molar ratio of the compound having the structure shown in Formula III, 4-dimethylaminopyridine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N,N-diisopropylethylamine is 1-1.5:2-2.5:2-2.5:5-7;

[0024] The molar ratio of the compound having the structure shown by formula III to the compound having the structure shown by formula IV is 1 to 1.5:1.

[0025] Preferably, the condensation reaction temperature is 20-25° C. and the reaction time is 8-12 hours.

[0026] Preferably, the deprotection reagent is trifluoroacetic acid; the temperature of the deprotection reaction is 20-25° C., and the time is 1-1.5 h.

[0027] The present invention also provides a pharmaceutically acceptable salt of the ester bond compound described in the above scheme or a tert-butyloxycarbonyl prodrug thereof; the structural formula of the tert-butyloxycarbonyl prodrug of the ester bond compound is shown in Formula V:

[0028] In Formula V, R is -Boc.

[0029] The present invention also provides the use of the ester bond compound described in the above scheme or the pharmaceutically acceptable salt of the ester bond compound described in the above scheme or its tert-butyloxycarbonyl prodrug in the preparation of analgesic drugs.

[0030] Preferably, the analgesic drug is a drug for treating acute pain or chronic pain.

[0031] The present invention also provides an analgesic drug, comprising an active ingredient and a pharmaceutically acceptable excipient; the active ingredient is the ester bond compound described in the above scheme or a pharmaceutically acceptable salt of the ester bond compound described in the above scheme or a tert-butyloxycarbonyl prodrug thereof.

[0032] The present invention provides an ester bond compound, the structural formula of which is shown in Formula I (denoted as SOP). Compared with the best analgesic combination "Sinomenine + Pregabalin" discovered in this laboratory, the ester bond compound provided by the present invention has a longer effective time and a stronger analgesic effect. At half the molar amount, it has a stronger analgesic effect, faster onset, longer analgesic time, and less fluctuation in efficacy than pregabalin, a first-line drug for treating pain; and the ester bond compound provided by the present invention may have a higher bioavailability, can achieve a stronger analgesic effect, and can reduce the occurrence of drug side effects by less dosage. In summary, the ester bond compound provided by the present invention can effectively control the development of the disease, improve the quality of life of patients, and has broad application prospects in the treatment of chronic pain. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The SOP prepared in Example 1 1 H-NMR spectrum;

[0034] Figure 2 is the MS spectrum of SOP;

[0035] Figure 3 is the HPLC chromatogram of SOP;

[0036] Figure 4 It is a schematic diagram of the SSNI model;

[0037] Figure 5 It is a line graph of the therapeutic effect of SOP hydrochloride on mechanical allodynia in SSNI rats;

[0038] Figure 6 It is a bar graph showing the therapeutic effect of SOP hydrochloride on mechanical allodynia in SSNI rats;

[0039] Figure 7 It is a bar graph showing the therapeutic effect of SOP hydrochloride on cold allodynia in SSNI rats;

[0040] Figure 8It is a line graph of the therapeutic effect of SOP tert-butyloxycarbonyl prodrug on mechanical allodynia in SSNI rats;

[0041] Fig. 9 This is a bar graph showing the therapeutic effect of SOP tert-butyloxycarbonyl prodrug on mechanical allodynia in SSNI rats;

[0042] Fig.10 This is a bar graph showing the therapeutic effect of SOP tert-butyloxycarbonyl prodrug on cold allodynia in SSNI rats;

[0043] Fig.11 Shown is the partial sciatic nerve ligation model (PSNL);

[0044] Fig.12 Results of postoperative mechanical allodynia in SSNI (left) and PSNL (right) models;

[0045] Fig.13 Results of postoperative cold allodynia in SSNI (left) and PSNL (right) models;

[0046] Fig.14 It is a line graph showing the therapeutic effect of SOP on mechanical allodynia in PSNL mice;

[0047] Fig.15 This is a bar graph showing the therapeutic effect of SOP on cold allodynia in PSNL mice (cold stimulation score);

[0048] Fig.16 Schematic diagram of the mouse incisional pain model;

[0049] Fig.17 This is a line graph showing the therapeutic effect of SOP on mechanical allodynia in the mouse incisional pain model.

[0050] Fig.18 This is a bar graph showing the therapeutic effect of SOP on cold allodynia in mice with incisional pain (cold stimulation score);

[0051] Fig.19 This is a bar graph showing the therapeutic effect of SOP on cold allodynia in mice with incisional pain (cold stimulus reaction time);

[0052] Fig. 20 This is a bar graph showing the therapeutic effect of SOP on thermal allodynia in the mouse incisional pain model;

[0053] Fig.21 The preventive effect of SOP pretreatment on mechanical allodynia in the mouse incisional pain model;

[0054] Fig. 22 The preventive effect of SOP pretreatment on cold allodynia in the mouse incisional pain model;

[0055] Fig.23The effect of SOP on the expression of NFkB (left) and IL-1β (right) in the spinal cord of PSNL mice;

[0056] Fig.24 The effect of sinomenine on the expression of TNF (left) and IL-6 (right) in the spinal cord of PSNL mice;

[0057] Fig.25 The cytotoxicity test results of SOP-Boc (left) and SOP hydrochloride (right). DETAILED DESCRIPTION

[0058] The present invention provides an ester bond compound (SOP), the structural formula of which is shown in Formula I:

[0059]

[0060] In the present invention, the chemical formula of the SOP is C 27 H 38 N2O5, molecular weight 470.6100, chemical name: (4bR,8aS,9S)-3,7-dimethoxy-11-methyl-6-oxo-6,8a,9,10-tetrahydro-5H-9,4b-(ethylcycloimino)phenanthrene-4-(S)-3-(methylamino)-5-methylhexanoic acid; SOP is unstable in methanol and ethyl acetate, but stable in petroleum ether, acetonitrile and hydrochloric acid.

[0061] The present invention also provides a method for preparing the ester bond compound described in the above scheme, comprising the following steps:

[0062] A compound having a structure shown in Formula II, a solvent, a base and Boc anhydride are mixed to carry out an amino protection reaction to obtain a compound having a structure shown in Formula III:

[0063] In formula III, R is -Boc;

[0064] The compound having the structure shown in Formula III, the compound having the structure shown in Formula IV, a condensing agent and a solvent are mixed to carry out a condensation reaction to obtain a compound having the structure shown in Formula V;

[0065] In Formula V, R is -Boc;

[0066] The amino-protected ester bond compound, a solvent and a deprotection agent are mixed to carry out a deprotection reaction to obtain an ester bond compound having a structure shown in Formula I.

[0067] The present invention mixes a compound having a structure shown in formula II (molecular weight: 159), a solvent, a base and Boc anhydride to carry out an amino protection reaction to obtain a compound having a structure shown in formula III. In the present invention, the solvent for the amino protection reaction is preferably dioxane and water, and the volume ratio of the dioxane and water is preferably 1:1 to 1.5; the base is preferably sodium hydroxide, and the sodium hydroxide is preferably used in the form of solid particles; the molar ratio of the compound having a structure shown in formula II to the base is preferably 1:1 to 1.5, more preferably 1:1.1; the molar ratio of the compound having a structure shown in formula II to Boc anhydride is preferably 1:1 to 1.5, more preferably 1:1.1.

[0068] In the present invention, the temperature of the amino protection reaction is preferably 20-25°C, and the time is preferably 1-1.5h. In a specific embodiment of the present invention, it is preferred to first dissolve the compound having the structure shown in Formula II in a solvent and place it in an ice bath, so that the system is colorless and transparent, then slowly add solid sodium hydroxide particles, and then slowly add Boc anhydride to the mixed solution using a constant pressure dropping funnel (the system is still colorless and transparent), and after the addition of Boc anhydride is completed, stir for 30 minutes under ice bath conditions, and then move to room temperature for amino protection reaction.

[0069] After the amino protection reaction is completed, the present invention preferably uses a citric acid aqueous solution to adjust the pH value of the obtained product solution to 4-5, then adds dichloromethane and washes with a saturated saline solution, collects the extract phase (organic phase), and dries the extract phase with anhydrous sodium sulfate, and then removes the solvent under reduced pressure to obtain amino-protected pregabalin; the mass fraction of the citric acid aqueous solution is preferably 10%.

[0070] After obtaining the compound having the structure shown in formula III, the present invention mixes the compound having the structure shown in formula III, the compound having the structure shown in formula IV, a condensation agent and a solvent for condensation reaction to obtain a compound having the structure shown in formula V. In the present invention, the condensation agent is preferably 4-dimethylaminopyridine (DMAP), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) and N,N-diisopropylethylamine (DIPEA); the molar ratio of the compound having the structure shown in formula III, DMAP, EDCI and DIPEA is preferably 1-1.5:2-2.5:5-7, more preferably 1.1:2:2:5; the molar ratio of the compound having the structure shown in formula III to the compound having the structure shown in formula IV is preferably 1-1.5:1, more preferably 1.1:1. In a specific embodiment of the present invention, the compound having the structure shown in formula IV is preferably used in the form of hydrochloride; the solvent for the condensation reaction is preferably dichloromethane, and the dichloromethane is preferably used after drying.

[0071] In the present invention, the temperature of the condensation reaction is preferably 20-25°C, and the time is preferably 8-12h; in a specific embodiment of the present invention, it is preferred to first dissolve the compound having the structure shown in Formula III in a solvent, and then add DMAP, EDCI and DIPEA in sequence, and then add the compound having the structure shown in Formula IV after stirring at room temperature for 30 minutes (the system gradually changes from light yellow turbid to light yellow transparent state), and then carry out the condensation reaction at room temperature.

[0072] After the condensation reaction is completed, the present invention preferably dilutes the obtained product liquid with dichloromethane, and then washes it with 1 mol / L hydrochloric acid solution, saturated sodium bicarbonate aqueous solution and saturated brine in sequence, collects the extract phase (organic phase), and dries the extract phase with anhydrous sodium sulfate, and then removes the solvent under reduced pressure to obtain a crude product; the crude product is purified by silica gel column chromatography to obtain a compound having a structure shown in Formula V (denoted as SOP-Boc, molecular weight: 571); the eluting reagent used for the silica gel column chromatography purification is preferably a mixed solvent of dichloromethane and methanol, and the volume ratio of dichloromethane to methanol in the mixed solvent is preferably 30:1.

[0073] After obtaining the compound having the structure shown in Formula V, the present invention mixes the compound having the structure shown in Formula V, a solvent and a deprotection agent to carry out a deprotection reaction to obtain an ester bond compound having the structure shown in Formula I. In the present invention, the solvent for the deprotection reaction is preferably dichloromethane, and the dichloromethane is preferably used after drying; the deprotection agent is preferably trifluoroacetic acid (TFA); the usage ratio of the compound having the structure shown in Formula V to trifluoroacetic acid is preferably 1g:3-5mL, and more preferably 1g:4mL.

[0074] In the present invention, the temperature of the deprotection reaction is preferably 20-25° C., and the time is preferably 1-1.5 h. In a specific embodiment of the present invention, it is preferred to first dissolve the compound having the structure shown in Formula V in a solvent, and then slowly add trifluoroacetic acid to the system using a constant pressure dropping funnel under ice bath conditions, continue stirring under ice bath conditions for 30 min, and then move to room temperature for deprotection reaction.

[0075] After the deprotection reaction is completed, the present invention preferably dilutes the obtained product solution with dichloromethane, then washes the organic phase with a saturated sodium bicarbonate aqueous solution until the pH of the aqueous phase is neutral, and then continues to wash with a saturated saline solution, collects the extract phase (organic phase), and dries the extract phase with anhydrous sodium sulfate, and then removes the solvent under reduced pressure to obtain an ester bond compound having a structure shown in Formula I (SOP, molecular weight: 478).

[0076] In the present invention, the synthesis route of the ester bond compound is shown in Formula A:

[0077]

[0078] The present invention also provides a pharmaceutically acceptable salt or a tert-butyloxycarbonyl prodrug thereof of the ester bond compound described in the above scheme; the present invention has no special requirements for the pharmaceutically acceptable salt, and a form familiar to those skilled in the art may be used, specifically the hydrochloride of the ester bond compound having a structure shown in Formula I; the tert-butyloxycarbonyl prodrug of the ester bond compound is the compound having a structure shown in Formula V described above (SOP-Boc), which will not be described in detail here; the Boc group of SOP-Boc can be completely metabolized and reduced in vivo; theoretically, SOP-Boc is more lipid soluble than SOP, which helps to increase bioavailability; the preparation method of SOP-Boc will not be described in detail here, and the product obtained from the aforementioned condensation reaction step is SOP-Boc.

[0079] The present invention also provides the use of the ester bond compound described in the above scheme, the pharmaceutically acceptable salt of the ester bond compound described in the above scheme, or its tert-butyloxycarbonyl prodrug in the preparation of analgesics. In the present invention, the analgesic is preferably a drug for treating acute pain or chronic pain, the acute pain specifically refers to perioperative pain, and the chronic pain specifically refers to neuropathic chronic pain; specifically, the analgesic is a drug for treating tissue damage pain, nerve damage pain, ischemic damage pain, perioperative pain, cancer pain, spinal cord injury pain, chronic pain caused by stroke, rheumatoid arthritis pain, diabetic peripheral nerve damage pain or AIDS peripheral nerve damage pain.

[0080] The present invention also provides an analgesic drug, comprising an active ingredient and a pharmaceutically acceptable excipient, wherein the active ingredient comprises the ester bond compound described in the above scheme or a pharmaceutically acceptable salt of the ester bond compound described in the above scheme or a tert-butyloxycarbonyl prodrug thereof; the present invention has no special requirements for the pharmaceutically acceptable excipient, and the excipients familiar to those skilled in the art can be used.

[0081] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0082] Example 1 Synthesis of SOP and SOP-Boc

[0083] 1) Amino protection:

[0084] Take a dry round-bottom flask, dissolve the compound (10g, 1eq) with the structure shown in formula II in 75mL dioxane and 75mL water, and place the system under an ice bath. The system is colorless and transparent. Slowly add sodium hydroxide solid particles (2.77g, 1.1eq), and slowly add Boc anhydride (13.8g, 1.1eq) to the mixed solution with a constant pressure dropping funnel. The system is still colorless and transparent. Continue stirring at 0℃ for 30min and then move to room temperature and stir for 1.5h. After the reaction is completed, take 5g of citric acid to prepare a 10% citric acid aqueous solution, slowly add citric acid aqueous solution to the system to adjust the pH to 4-5, add 300mL of dichloromethane and wash with saturated salt water, collect the extract, and dry it with anhydrous sodium sulfate overnight. Remove the solvent under reduced pressure to obtain 16g of white solid, i.e., the compound with the structure shown in formula III, with a yield of 98%.

[0085] 2) Preparation of SOP-Boc (Formula V):

[0086] Take a dry round-bottom flask, dissolve the compound with the structure shown in formula III (14g, 1.1eq) completely in 200mL dry dichloromethane, continue to add DMAP (12.1g, 2eq), EDCI (18.9g, 2eq), DIPEA (31.8g, 5eq) in turn, stir at room temperature for 30min, add the hydrochloride of the compound with the structure shown in formula IV (18g, 1eq), the system gradually changes from light yellow turbidity to light yellow transparent state, stir at room temperature for 12h. Add 100mL dichloromethane to dilute, wash with 1mol / L HCl solution, saturated sodium bicarbonate aqueous solution, and saturated salt water respectively, collect the extract phase, and dry it over anhydrous sodium sulfate overnight. After removing the solvent under reduced pressure, the crude product is purified by silica gel column (DCM: MeOH = 30: 1) to obtain 9.2g of pure white solid, namely compound SOP-Boc.

[0087] 3) Preparation of SOP (deamino protection):

[0088] Take a dry round-bottom flask, dissolve the compound SOP-Boc (5g) in 60mL dry dichloromethane and place the system in an ice bath. The system is colorless and transparent. Slowly add 20mL TFA to the system with a constant pressure dropping funnel, continue stirring for 30min, and then move to room temperature and stir for 1.5h. Add 50mL of dichloromethane to dilute, wash the organic phase with saturated sodium bicarbonate aqueous solution until the pH of the aqueous phase reaches about 7, continue washing with 100mL of saturated salt water solution, collect the extract, and dry it over anhydrous sodium sulfate overnight. The solvent was drained under reduced pressure to obtain 3.65g of white solid, i.e., compound SOP, with a yield of 73%.

[0089] Figure 1 For SOP 1H-NMR spectrum; Figure 2 is the MS spectrum of SOP; Figure 3 Table 1 is the HPLC high performance liquid chromatogram of SOP; Table 2 is the spectral data corresponding to the HPLC high performance liquid chromatogram; 1 Summary of the test results corresponding to the H-NMR spectrum, mass spectrum, and HPLC.

[0090] Table 1 HPLC chromatogram data

[0091] Peak Retention time area Peak height area 1 7.371 76991 1294 100％ total 76991 1294 100％

[0092] Table 2 Summary of test results

[0093]

[0094] According to the above results, it can be seen that the SOP prepared by the present invention does have the target structure and the product purity is high.

[0095] Example 2 Study on the efficacy of SOP compounds using the rat SSNI model

[0096] 1. Establishment of SSNI peripheral neuropathy rat model

[0097] Figure 4 The schematic diagram of the SSNI model is shown below. The surgical procedure of the SSNI model is briefly described as follows:

[0098] 1) After the rats were anesthetized with chloral hydrate (5%), the skin of the left hind limb of the rats was cut open with scissors and the biceps femoris muscle was cut along the femur to expose the sciatic nerve and its three terminal branches: the sural nerve, the common peroneal nerve and the tibial nerve.

[0099] 2) Follow the sciatic nerve downward to find the common peroneal nerve and tibial nerve. Then use butterfly scissors to cut the axons of the common peroneal nerve and tibial nerve, being careful not to touch or stretch the distal sural nerve.

[0100] 3) Use No. 5 wire to pierce the upper end (dorsal end) of the severed common peroneal nerve and tibial nerve, and remove 2 to 4 mm of the remaining nerve at the lower end.

[0101] 4) Put the torn muscle back and sew the muscle and skin with two stitches using No. 5 thread; during the operation, place the rat on a heating pad to maintain the body temperature between 35 and 38°C.

[0102] Pharmacological experiments were performed 14 days after surgery to observe the effects of the drugs on mechanical allodynia and cold allodynia (and to observe whether there were any side effects).

[0103] The mechanical allodynia test protocol is as follows: the rat is placed in a plastic cage with a metal mesh bottom. After acclimation for 1 hour, a standard VonFrey fiber is used to stimulate the sole of the rat's left hind paw with gradually increasing force until the rat's hind paw retracts. During the test, pressure is applied 5 (10) times at a frequency of 1 time / s, and the reaction threshold is reached when the rat's hind paw retracts at least 3 (6 times).

[0104] The cold pain sensitivity test protocol is as follows: acetone is dropped on the surface of the plantar surface of the hind paw to test the rat's cold pain sensitivity. The rat's immediate reaction to the application of acetone is observed, and the reaction time is recorded and the degree of reaction is scored. The reaction time is the duration corresponding to the reaction of lifting the foot, rapid shaking, and licking the sole of the foot after acetone stimulation. The scoring criteria are: 0 = no reaction; 1 = startle reaction, no obvious retraction of the hind paw; 2 = retraction of the stimulated hind paw; 3 = continuous retraction of the stimulated hind paw, accompanied by trembling and licking of the hind limbs.

[0105] 2. Experimental Grouping

[0106] 1) SOP 0.03 group: “SOP hydrochloride 0.03 nmol / kg” group: After successful modeling, 0.03 nmol / kg SOP-HCl was administered intragastrically, and the mechanical pain threshold and cold pain sensitivity threshold were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, 360 min, 8 h, and 24 h.

[0107] 2) SOP 0.06 group: “SOP hydrochloride 0.06nmol / kg” group: After successful modeling, 0.06nmol / kg SOP-HCl was administered intragastrically, and the mechanical pain threshold and cold pain sensitivity threshold were measured at 0min (baseline), 30min, 60min, 120min, 240min, 360min, 8h, and 24h.

[0108] 3) SOP-Boc 0.03 group: “tert-butyloxycarbonyl prodrug of SOP 0.03 nmol / kg” group; after successful model establishment, 0.03 nmol / kg of SOP-Boc was administered intragastrically, and the mechanical pain threshold and cold pain sensitivity threshold were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, 360 min, 8 h, and 24 h.

[0109] 4) SOP-Boc 0.06 group: "SOP tert-butyloxycarbonyl prodrug 0.06nmol / kg" group; after successful modeling, 0.06nmol / kg of SOP-Boc was administered intragastrically, and the mechanical pain threshold and cold pain sensitivity threshold were measured at 0min (baseline), 30min, 60min, 120min, 240min, 360min, 8h, and 24h.

[0110] 5) Sinomenine + Pregabalin 0.06 group: "Sinomenine + Pregabalin 0.06nmol / kg" group; after successful modeling, 0.06nmol / kg Sinomenine and 0.06nmol / kg Pregabalin were administered by oral gavage at the same time, and the mechanical pain threshold and cold pain sensitivity threshold were measured at 0min (baseline), 30min, 60min, 120min, 240min, 360min, 8h, and 24h.

[0111] 6) "Vehicle control" group: After successful modeling, normal saline was administered by gavage, and the mechanical pain threshold and cold pain sensitivity threshold were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, 360 min, 8 h, and 24 h.

[0112] 3. Experimental results

[0113] 1) Therapeutic effect of SOP hydrochloride on mechanical allodynia in SSNI rats

[0114] Figure 5 It is a line graph of the therapeutic effect of SOP hydrochloride on mechanical allodynia in SSNI rats; Figure 6 It is a bar graph showing the therapeutic effect of SOP hydrochloride on mechanical allodynia in SSNI rats; Figures 5-6 Middle: *P<0.05, **P<0.01, ***P<0.001 (compared with the threshold value of its own baseline (BL) at different time points), #P<0.05, ##P<0.01, ###P<0.001 (compared with the threshold value of the vehicle control group at the same time point), $P<0.05, $$P<0.01, $$$P<0.001 (compared with the threshold value of the “sinomenine + pregabalin 0.06nmol / kg” group at the same time point).

[0115] SOP-HCl is the hydrochloride salt of SOP. Figures 5-6It can be seen that after administration, SOP-HCl produced a dose-dependent inhibitory effect on mechanical hyperalgesia in SSNI rats at doses of 0.03nmol / kg (significant analgesia at the 4h time point compared with baseline) and 0.06nmol / kg (significant analgesia from 0.5 to 8h compared with baseline) (the gray shaded area represents the normal threshold range of non-injured animals). In addition, the mechanical pain threshold of the SOP-0.06 group was significantly higher than that of the sinomenine and pregabalin combination group (0.06nmol / kg; no significant effect within the test time) within 0.5 to 2h. The above results confirmed our previous expectations: for mechanical hyperalgesia, SOP hydrochloride has a stronger analgesic effect and longer analgesic duration than the current best drug combination of "sinomenine + pregabalin".

[0116] 2) Therapeutic effect of SOP hydrochloride on cold allodynia in SSNI rats

[0117] Figure 7 This is a bar graph showing the therapeutic effect of SOP-HCl on cold allodynia in SSNI rats. Figure 7 Middle: *P<0.05, **P<0.01, ***P<0.001 (compared with the threshold value of its own baseline (BL) at different time points), #P<0.05, ##P<0.01, ###P<0.001 (compared with the threshold value of the vehicle control group at the same time point), $$$P<0.001 (compared with the threshold value of the "sinomenine + pregabalin 0.06nmol / kg" group at the same time point).

[0118] according to Figure 7 It can be seen that after administration, SOP-HCl produced a dose-dependent inhibitory effect on the cold allodynia of rats at a dose of 0.03nmol / kg (at 0.5, 1, 6, and 8h, compared with the baseline or blank control group, there was a significant anti-cold allodynia effect) and 0.06nmol / kg (at 0.5, 1, and 3h, a significant effect was produced compared with the baseline) (the gray shaded area represents the normal threshold range of uninjured animals). In addition, the cold pain threshold of the SOP-0.06 group was significantly higher than that of the sinomenine and pregabalin combination group at the 0.5h time point (0.06nmol / kg; there was a significant anti-cold allodynia effect within 1 to 8h). The above results confirm that for cold allodynia, compared with the combination of "sinomenine + pregabalin", SOP hydrochloride has a stronger analgesic effect at individual time points, but does not have a longer duration of analgesia.

[0119] 3) Therapeutic effect of SOP tert-butyloxycarbonyl prodrug on mechanical allodynia in SSNI rats

[0120] Figure 8This is a line graph showing the therapeutic effect of SOP tert-butyloxycarbonyl prodrug on mechanical allodynia in SSNI rats. Fig. 9 This is a bar graph showing the therapeutic effect of SOP tert-butyloxycarbonyl prodrug on mechanical allodynia in SSNI rats.

[0121] SOP-Boc is the tert-butyloxycarbonyl prodrug of SOP. Figures 8-9 It can be seen that after administration, at a dose of 0.03 nmol / kg (significant analgesic effect at the 2h time point compared with the baseline), SOP-Boc inhibited the mechanical allodynia of SSNI rats (the gray shaded area represents the threshold range of normal mechanical pain in uninjured animals), but at a dose of 0.06 nmol / kg, no significant analgesic effect was produced during the observation time, so it was not dose-dependent. There was no significant difference between the SOP-Boc 0.06 group and the sinomenine and pregabalin combination group (0.06 nmol / kg; no significant anti-mechanical allodynia effect during the test time). The above results prove that for mechanical allodynia, the tert-butyloxycarbonyl prodrug of SOP is similar to the combination of "sinomenine + pregabalin".

[0122] 4) Therapeutic effect of SOP tert-butyloxycarbonyl prodrug on cold allodynia in SSNI rats

[0123] Fig.10 It is a bar graph of the therapeutic effect of SOP tert-butyloxycarbonyl prodrug on cold allodynia in SSNI rats, where: *P<0.05, **P<0.01, ***P<0.001 (comparison with the threshold value of its own baseline (BL) at different time points), ##P<0.01, ###P<0.001 (comparison with the threshold value of the vehicle control group at the same time point).

[0124] according to Fig.10 It can be seen that after administration, at a dose of 0.06 nmol / kg (at 1 and 6 h time points, there was a significant anti-cold hyperalgesia effect compared with the baseline), SOP-Boc had an inhibitory effect on the cold hyperalgesia of SSNI rats (the gray shaded area represents the range of normal thresholds of uninjured animals). At a dose of 0.03 nmol / kg, SOP-Boc had no significant anti-cold hyperalgesia effect during the observation period. For cold hyperalgesia, compared with the combination of "sinomenine + pregabalin", the tert-butyloxycarbonyl prodrug of SOP did not have a stronger analgesic effect or produce a longer duration of analgesia.

[0125] The above results showed that in the rat SSNI model, SOP hydrochloride had a better analgesic effect than the combination of sinomenine and pregabalin at the same dose, while there was no significant difference in the analgesic effect between SOP tert-butyloxycarbonyl prodrug and the combination of sinomenine and pregabalin.

[0126] Example 3 Study on the efficacy of SOP compounds using a mouse peripheral nerve injury model

[0127] 1. Selection of mouse peripheral nerve injury model (SSNI vs. PSNL)

[0128] Since the research subjects were changed from rats to mice, the present invention compared the modeling effects of two different peripheral neuropathy models, SSNI and PSNL, on mice, and selected an optimal model for subsequent efficacy studies of SOP compounds. Fig.11 The figure shows the operation of the partial sciatic nerve ligation model (PSNL), which can produce chronic pain lasting more than 8 weeks by ligating the sciatic nerve from the thigh to the 1 / 2 point of the spinal cord.

[0129] Fig.12 Results of postoperative mechanical allodynia in SSNI (left) and PSNL (right) models. Fig.13 The results of postoperative cold allodynia in SSNI (left) and PSNL (right) models. By comparing the SSNI and PSNL models, it was found that mechanical allodynia and cold allodynia in the PSNL model occurred faster and more persistently after surgery. However, the SSNI model showed an unstable phenomenon of increased mechanical allodynia threshold (9-14 days compared with the 7th day). Therefore, the present invention selected the PSNL model for the efficacy study of SOP compounds, and the following pharmacological experiments were performed 12 days after surgery.

[0130] 2. Experimental Grouping

[0131] 1) SOP 0.06 group: "SOP 0.06nmol / kg" group: After successful modeling, 0.06nmol / kg of SOP was administered by gavage, and the mechanical pain and cold pain sensitivity thresholds were measured at 0min (baseline), 30min, 60min, 120min, 240min, 360min, 8h, and 24h.

[0132] 2) Sinomenine 0.12 group: After successful modeling, 0.12 nmol / kg of Sinomenine was administered by oral gavage, and the mechanical pain and cold pain sensitivity thresholds were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, 360 min, 8 h, and 24 h.

[0133] 3) Pregabalin 0.12 group: After successful modeling, 0.12 nmol / kg of pregabalin was administered intragastrically, and the mechanical pain and cold pain sensitivity thresholds were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, 360 min, 8 h, and 24 h.

[0134] 4) Sinomenine + Pregabalin 0.06 group: "Sinomenine + Pregabalin 0.06nmol / kg" group; after the model was successfully established, 0.06nmol / kg Sinomenine and 0.06nmol / kg Pregabalin were administered by oral gavage at the same time, and the mechanical pain and cold pain sensitivity thresholds were measured at 0min (baseline), 30min, 60min, 120min, 240min, 360min, 8h, and 24h.

[0135] 5) Vehicle control group: After successful modeling, normal saline was administered by gavage, and the mechanical pain and cold pain sensitivity thresholds were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, 360 min, 8 h, and 24 h.

[0136] The testing methods for mechanical allodynia and cold allodynia were the same as those in Example 2.

[0137] 3. Experimental results

[0138] 1) The therapeutic effect of SOP on mechanical allodynia in PSNL mice

[0139] Fig.14 It is a line graph of the therapeutic effect of SOP on mechanical allodynia in PSNL mice, where: *P<0.05, **P<0.01, ***P<0.001 (comparison with the threshold of the baseline (BL) at different time points), ##P<0.01 (comparison with the threshold of the vehicle control group at the same time point).

[0140] SOP is a molecule that combines sinomenine (not salified with hydrochloric acid) with pregabalin. Fig.14 As shown in the figure, after administration, at a dose of 0.06 nmol / kg (significant analgesic effect from 4h to 24h compared with the baseline), SOP has an inhibitory effect on the mechanical allodynia of PSNL mice (the gray shaded area represents the threshold range of normal mechanical pain in uninjured animals). At the 6, 8, and 24h time points, the analgesic effect produced by 0.06nmol / kg SOP is significantly better than the double dose (0.12nmol / kg) of sinomenine (no significant analgesic effect during the test time) and pregabalin (only significant anti-mechanical allodynia effect at 2h), or the same dose (0.06nmol / kg) of sinomenine and pregabalin combined (only significant anti-mechanical allodynia effect at 2 and 4h time points). Therefore, for the mechanical allodynia produced by the PSNL model, the efficacy of SOP shows a lag, but the therapeutic effect and duration are significantly better than the double dose of sinomenine, pregabalin, or the same dose of "sinomenine + pregabalin" combined.

[0141] 2) The therapeutic effect of SOP on cold allodynia in PSNL mice

[0142] Fig.15 It is a bar graph showing the therapeutic effect of SOP on cold allodynia in PSNL mice (cold stimulation score), where: #P<0.05 (compared with the threshold value of the vehicle control group at the same time point).

[0143] according to Fig.15 It can be seen that at a dose of 0.06nmol / kg (cold stimulation score; at the 4h time point, there was a significant analgesic effect compared with the blank), SOP had an inhibitory effect on the cold pain sensitivity of PSNL mice (the gray shaded area represents the normal threshold range of uninjured animals), and at the 4h time point, the analgesic effect of 0.06nmol / kg SOP was not significantly different from the same dose (0.06nmol / kg) of sinomenine and pregabalin combined. However, double doses (0.12nmol / kg) of sinomenine and pregabalin had no significant anti-cold pain sensitivity effect during the observation time (although a trend of reduced cold pain sensitivity was shown within 1 to 8h).

[0144] Example 4 Study on the efficacy of SOP compounds using a mouse incisional pain model

[0145] 1. Establishment of incision pain model

[0146] Fig.16 This is a schematic diagram of the mouse incision pain model; a brief description of the postoperative pain mouse model is as follows:

[0147] 1) After the mice were anesthetized with chloral hydrate (5%), a 0.5 cm incision was made along the central axis of the mouse's hind paw (left paw was used as incision, right paw was used as control) at 0.2 cm near the heel, and the incision passed through the skin, fascia and muscle.

[0148] 2) Then use bent tweezers to insert the exposed muscles and tendons (do not damage the integrity of the muscles and tendons), penetrate from the bottom, and then tear it open with force.

[0149] 3) Put the torn muscle back and sew it up with two stitches using No. 5 thread. During the operation, place the mouse on a heating pad to maintain the body temperature between 35 and 38°C. Remove the stitches the next day.

[0150] 4) Measure the mechanical threshold around the wound and compare it with that before the injury. Postoperative pain should be restored after 5 days, and the efficacy indexes including mechanical allodynia, cold allodynia and heat allodynia should be tested after 24 hours.

[0151] Among them, the test schemes for mechanical allodynia and cold allodynia are the same as in Example 2; the test scheme for thermal allodynia is as follows: a radiant heat source (Ugo Basile, Italy) is placed on the plantar surface of the hind paw to measure thermal allodynia. The machine will automatically record the hind paw withdrawal latency. The stimulus intensity is adjusted so that the baseline latency of normal animals is set at 2 to 6 seconds, the cutoff time of rats is set at 20 seconds, and the cutoff time of mice is set at 15 seconds.

[0152] 2. Experimental Grouping

[0153] 1) SOP 0.06 group: After successful modeling, 0.06 nmol / kg of SOP was administered by gavage, and the thresholds of mechanical pain, cold allodynia, and heat allodynia were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, and 360 min.

[0154] 2) Sinomenine 0.12 group: After successful modeling, 0.12 nmol / kg of Sinomenine was administered intragastrically, and the thresholds of mechanical pain, cold allodynia, and heat allodynia were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, and 360 min.

[0155] 3) Pregabalin 0.12 group: After successful modeling, 0.12 nmol / kg of pregabalin was administered intragastrically, and the thresholds of mechanical pain, cold allodynia, and heat allodynia were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, and 360 min.

[0156] 4) Vehicle control group: After successful modeling, normal saline was administered by gavage, and the thresholds of mechanical pain, cold allodynia, and heat allodynia were measured at 0 min (baseline), 30 min, 60 min, 120 min, 240 min, and 360 min.

[0157] 3. Experimental results

[0158] 1) The therapeutic effect of SOP on mechanical allodynia in the mouse incisional pain model

[0159] Fig.17 This is a line graph of the therapeutic effect of SOP on mechanical pain in the mouse incisional pain model, where: *P<0.05 (compared with the threshold of its own baseline (BL) at different time points).

[0160] according to Fig.17It can be seen that after administration, at a dose of 0.06nmol / kg (at the 2h time point, there was a significant analgesic effect compared to the baseline), SOP had an inhibitory effect on the mechanical allodynia of mice with incisional pain (the gray shaded area represents the range of normal mechanical pain thresholds of uninjured animals). Within the observation time range after administration, the analgesic effect produced by 0.06nmol / kg SOP was not significantly different from that of 0.12nmol / kg sinomenine (no significant anti-mechanical allodynia effect within the test time) and 0.12nmol / kg pregabalin (only had a significant anti-mechanical allodynia effect at the 4h time point). Therefore, for the mechanical allodynia of the incisional pain mouse model, the efficacy of SOP is similar to that of double doses of sinomenine and pregabalin.

[0161] 2) The therapeutic effect of SOP on cold allodynia in the mouse incisional pain model

[0162] Fig.18 This is a bar graph showing the therapeutic effect of SOP on cold allodynia in mice with incisional pain (cold stimulation score); Fig.19 This is a bar graph showing the therapeutic effect of SOP on cold allodynia in mice with incisional pain (cold stimulus reaction time).

[0163] according to Fig.18 As shown in Figure 2, all medication groups (except the blank control group) showed a trend of decreased sensitivity to cold stimulation (decreased scores). When the evaluation method of cold pain sensitivity was changed from cold stimulation score to cold stimulation reaction time (such as Fig.19 As shown in the figure, at a dose of 0.06nmol / kg (at the 6h time point, the reaction time was significantly reduced compared with the blank), SOP had an inhibitory effect on the cold hyperalgesia of mice with incisional pain (the gray shaded area represents the range of normal thresholds of uninjured animals), and 0.12nmol / kg sinomenine and 0.12nmol / kg pregabalin had no significant anti-cold hyperalgesia effect during the observation time. Therefore, SOP administration can effectively reduce the cold hyperalgesia of mice with incisional pain, and the therapeutic effect of SOP is better than double doses of sinomenine or pregabalin.

[0164] 3) The therapeutic effect of SOP on thermal hyperalgesia in the mouse incisional pain model

[0165] Fig. 20 It is a bar graph showing the therapeutic effect of SOP on thermal allodynia in the mouse incision pain model, where: *P<0.05 (compared with the threshold of its own baseline (BL) at different time points).

[0166] like Fig. 20As shown in the figure, at a dose of 0.06nmol / kg (thermal stimulation score; at the 2h time point, there was a significant analgesic effect compared with the blank control), SOP had an inhibitory effect on the thermal allodynia of mice with incisional pain (the gray background represents the normal threshold range of non-injured animals), and 0.12nmol / kg sinomenine and 0.12nmol / kg pregabalin had no significant anti-thermal allodynia effect during the observation time. Therefore, the therapeutic effect of SOP on thermal allodynia in the incisional pain mouse model is better than double doses of sinomenine or pregabalin.

[0167] 4) Preventive effect of SOP compounds on incisional pain in mice

[0168] Because perioperative pain can develop into chronic pain if not properly managed, whether preoperative SOP administration can prevent the occurrence of mechanical allodynia and cold allodynia in incisional pain model mice is also an important focus of the present invention. 2 hours before incision surgery, mice were gavaged with 60 mg / kg of SOP, and the preventive effect of mechanical allodynia and cold allodynia on different days after surgery was tested.

[0169] Fig.21 The SOP pretreatment has a preventive effect on mechanical allodynia in the mouse incisional pain model. Fig. 22 The preventive effect of SOP pretreatment on cold allodynia in the mouse incisional pain model. Figures 21-22 Middle: *P<0.05, **P<0.01 (compared with the threshold of baseline (BL) at different time points).

[0170] like Fig.21 As shown, under normal circumstances, the mechanical threshold of mice undergoing surgery will be significantly reduced within 24 to 48 hours after incision surgery, and will return to normal from the third day; however, after pretreatment with 60 mg / kg of SOP, the mechanical pain threshold of mice undergoing surgery did not show significant difference compared with that before surgery, proving that SOP pretreatment can prevent the occurrence of mechanical pain sensitivity in mice with incisional pain.

[0171] like Fig. 22 As shown in the figure, under normal circumstances, cold pain sensitivity occurs 24 hours after incision surgery. The mice in the blank control group developed relatively severe cold pain sensitivity 1, 2, and 4 days after surgery (most mice had cold stimulation scores > 1). After pretreatment with 60 mg / kg SOP, the cold pain threshold of the mice undergoing surgery was not significantly different from that before surgery (the gray background represents the normal threshold range of uninjured animals), proving that SOP pretreatment can prevent the occurrence of cold pain sensitivity in mice with incisional pain.

[0172] Example 5 Molecular biological mechanism of SOP against neuroinflammation

[0173] Inflammatory cytokines are not only the cause of inflammatory pain, but also play a key role in peripheral or central neuropathic pain. In nerve tissue, inflammatory cytokines such as IL1-β, TNF and IL-6 are released through the activation of the NFkB pathway. These inflammatory factors can further activate glutamate receptors such as NMDA and AMPA to produce a persistent pain state. The present invention uses the PSNL model to study the effect of SOP administration on the expression of inflammatory cytokines in the spinal cord tissue of mice with peripheral neuropathy. The construction method of the PSNL model is the same as that of Example 3.

[0174] 1. Experimental Grouping

[0175] 1) SOP 0.06 group: "SOP 0.06nmol / kg" group: After the model was successfully established, 0.06nmol / kg of SOP was administered by gavage, and spinal cord tissue was obtained 3 hours after administration, and the expression of inflammatory cytokines was analyzed by qPCR.

[0176] 2) Sinomenine 0.12 group: "Sinomenine 0.12nmol / kg" group; after successful modeling, 0.12nmol / kg of Sinomenine was administered by gavage, and spinal cord tissue was obtained 3 hours after administration, and the expression of inflammatory cytokines was analyzed by qPCR.

[0177] 3) Pregabalin 0.12 group: "Pregabalin 0.12nmol / kg" group: After the model was successfully established, 0.12nmol / kg of pregabalin was administered intragastrically, and spinal cord tissue was obtained 3 hours after administration, and the expression of inflammatory cytokines was analyzed by qPCR.

[0178] 4) Sinomenine + Pregabalin 0.06 group: "Sinomenine + Pregabalin 0.06nmol / kg" group; after the model was successfully established, 0.06nmol / kg Sinomenine and 0.06nmol / kg Pregabalin were administered by gavage at the same time, and the spinal cord tissue was obtained 3 hours after administration, and the expression of inflammatory cytokines was analyzed by qPCR.

[0179] 5) Vehicle control group: After successful modeling, normal saline was administered by gavage, and spinal cord tissue was obtained 3 hours after administration, and the expression of inflammatory cytokines was analyzed by qPCR.

[0180] 6) Normal group: Normal mice of the same age were used without any drug treatment. Spinal cord tissues were obtained and the expression of inflammatory cytokines was analyzed by qPCR.

[0181] 2. Experimental results

[0182] Fig.23 The effect of SOP on the expression of NFkB (left) and IL-1β (right) in the spinal cord of PSNL mice; Fig.24The effect of sinomenine on the expression of TNF (left) and IL-6 (right) in the spinal cord of PSNL mice. Figures 23-24 Middle: ns indicates no significant difference, * indicates P ≤ 0.05.

[0183] like Fig.23 As shown in the results, at a dose of 0.06 nmol / kg, SOP showed an inhibitory trend on the expression of NFkB transcription factor, TNF, IL-1β and IL-6 in PSNL mice, among which the inhibitory effect of SOP on TNF and IL-1β (relative to the vehicle control group) was statistically significant, far superior to the positive drug control group including sinomenine 0.12 nmol / kg, pregabalin 0.12 nmol / kg, or sinomenine + pregabalin 0.06 nmol / kg.

[0184] like Fig.24 As shown in the results, SOP 0.06nmol / kg can significantly reverse the expression of central TNF and IL-1β in PSNL mice, revealing that SOP can exert analgesic pharmacological effects through central anti-inflammatory mechanisms.

[0185] Example 6 Safety of SOP Compounds

[0186] At the dosages involved in the present invention, SOP, SOP hydrochloride and tert-butyloxycarbonyl prodrug of SOP did not produce any observable adverse reactions (such as allergic reactions, slow movement, respiratory depression, etc.) after administration to (rat / mice). In order to further reveal the safety of SOP compounds, the present invention uses Caco2 cells to detect the proportion of cell apoptosis as the concentration of SOP hydrochloride (SOP will also exist in the gastric juice in the form of SOP hydrochloride after oral administration) or SOP-Boc in the external environment gradually increases.

[0187] Fig.25 The cytotoxicity test results of SOP-Boc (left) and SOP hydrochloride (right). Fig.25 It can be seen that as the concentration of SOP-Boc increases, when LogC reaches above 2.0, more than 90% of cells will undergo apoptosis. However, for SOP hydrochloride, the same increase in concentration does not cause significant cell death (when LogC is 2.0, the cell survival rate is above 90%), and when LogC continues to increase to above 2.5, more than 70% of cells survive. Therefore, the safety of SOP hydrochloride is significantly better than that of SOP-Boc.

[0188] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An ester bond compound, the structural formula of which is shown in Formula I:

2. The method for preparing the ester bond compound according to claim 1, comprising the following steps: A compound having a structure shown in Formula II, a solvent, a base and Boc anhydride are mixed to carry out an amino protection reaction to obtain a compound having a structure shown in Formula III: In formula III, R is -Boc; The compound having the structure shown in Formula III, the compound having the structure shown in Formula IV, a condensing agent and a solvent are mixed to carry out a condensation reaction to obtain a compound having the structure shown in Formula V; In Formula V, R is -Boc; The compound having the structure shown in Formula V, a solvent and a deprotection agent are mixed to carry out a deprotection group reaction to obtain an ester bond compound having the structure shown in Formula I.

3. The preparation method according to claim 2, characterized in that: The base is sodium hydroxide; the molar ratio of the compound having the structure shown in formula II to the base is 1:1-1.5; the molar ratio of the compound having the structure shown in formula II to Boc anhydride is 1:1-1.5; the temperature of the amino protection reaction is 20-25°C, and the time is 1-1.5h.

4. The preparation method according to claim 2, characterized in that: The condensing agent is 4-dimethylaminopyridine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N,N-diisopropylethylamine; the molar ratio of the compound having the structure shown in formula III, 4-dimethylaminopyridine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N,N-diisopropylethylamine is 1-1.5:2-2.5:2-2.5:5-7; The molar ratio of the compound having the structure shown by formula III to the compound having the structure shown by formula IV is 1 to 1.5:

1.

5. The preparation method according to claim 2, characterized in that: The temperature of the condensation reaction is 20-25° C. and the time is 8-12 hours.

6. The preparation method according to claim 2, characterized in that: The deprotection reagent is trifluoroacetic acid; the temperature of the deprotection reaction is 20-25° C., and the time is 1-1.5 h.

7. The pharmaceutically acceptable salt of the ester bond compound of claim 1 or its tert-butyloxycarbonyl prodrug; the structural formula of the tert-butyloxycarbonyl prodrug of the ester bond compound is as shown in Formula V: In Formula V, R is -Boc.

8. Use of the ester bond compound according to claim 1 or the pharmaceutically acceptable salt of the ester bond compound according to claim 7 or its tert-butyloxycarbonyl prodrug in the preparation of analgesics.

9. The use according to claim 8, characterized in that: The analgesic drug is a drug for treating acute pain or chronic pain.

10. An analgesic drug, characterized in that: It comprises an active ingredient and a pharmaceutically acceptable excipient; the active ingredient is the ester bond compound according to claim 1 or a pharmaceutically acceptable salt of the ester bond compound according to claim 7 or a tert-butyloxycarbonyl prodrug thereof.

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