A class of hydroxyphenylpyridazine Mannich base compounds and preparation method and use thereof

Abstract

The present invention discloses a class of hydroxyphenylpyridazine Mannich base compounds (I) and pharmaceutically acceptable salts thereof, a preparation method thereof, a pharmaceutical composition and use thereof in preparing drugs for treating and / or preventing diseases related to the nervous system, including but not limited to vascular dementia, Alzheimer's disease, frontotemporal dementia, prion disease, Lewy body dementia, Parkinson's disease, Huntington's disease, HIV-related dementia, multiple sclerosis, amyotrophic lateral sclerosis, neuropathic pain, ischemic stroke, hemorrhagic stroke and nerve damage caused by brain trauma; #imgabs0#

Description

Technical Field

[0001] The present invention belongs to the field of pharmaceutical chemistry and relates to a class of hydroxyphenylpyridazine Mannich base compounds (I) and pharmaceutically acceptable salts thereof, a preparation method thereof, a pharmaceutical composition and use thereof in preparing drugs for treating and / or preventing diseases related to the nervous system, including but not limited to vascular dementia, Alzheimer's disease, frontotemporal dementia, prion disease, Lewy body dementia, Parkinson's disease, Huntington's disease, HIV-related dementia, multiple sclerosis, amyotrophic lateral sclerosis, neuropathic pain, ischemic stroke, hemorrhagic stroke and nerve damage caused by brain trauma. Background Art

[0002] Neurodegenerative diseases refer to a general term for diseases caused by chronic progressive degeneration of central nervous system tissues, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). Their pathogenesis is closely related to oxidative stress, neuroinflammation and corresponding damage. Oxidative stress is mediated by reactive oxygen species (ROS) free radicals, including superoxide anions, hydrogen peroxide and hydroxyl free radicals. Under normal physiological conditions, the level of ROS generation is in a dynamic equilibrium with the body's antioxidant capacity. When the generation of ROS exceeds the antioxidant capacity of cells, oxidative stress will occur. The brain is particularly sensitive to oxidative stress, which can induce a variety of neurological diseases. Other studies have found that vascular dementia, HIV-related dementia, neuropathic pain, ischemic stroke, hemorrhagic stroke, and nerve damage caused by brain trauma are also closely related to the body's oxidative stress and neuroinflammation.

[0003] Vascular dementia (VD) is a clinical syndrome of intellectual and cognitive dysfunction caused by various types of cerebrovascular diseases (including ischemic cerebrovascular disease, hemorrhagic cerebrovascular disease, acute and chronic hypoxic cerebrovascular disease, etc.). Due to the complex pathogenesis of vascular dementia, there is currently no drug that can block the development of the disease. Clinical treatment focuses on improving brain blood circulation, brain metabolism, and strengthening brain nutrition.

[0004] Alzheimer's disease (AD) is a degenerative disease of the central nervous system characterized by progressive cognitive impairment and memory loss. Its incidence rate is increasing year by year, becoming a high-incidence disease second only to cardiovascular disease and cancer. With the acceleration of the aging process of the global population, its incidence rate is showing a clear upward trend. It is estimated that there are more than 50 million people suffering from dementia in the world, and the total cost of treatment and care has exceeded 1 trillion US dollars in 2018. By 2050, the number of patients will increase to 152 million. Since the clinical manifestations of AD are impaired memory, orientation, thinking and judgment, as well as reduced daily living ability, and even abnormal mental and behavioral symptoms, it is difficult to care for patients, which brings a heavy burden to society and families. Currently, the drugs approved for the treatment of mild / moderate AD include acetylcholinesterase (AChE) inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonists for the treatment of severe AD. However, clinical use shows that these drugs can relieve AD symptoms by increasing the level of acetylcholine in patients or inhibiting the excitotoxicity of excitatory amino acids, but they cannot effectively prevent or reverse the course of the disease. In addition, they can cause serious side effects such as hallucinations, confusion, dizziness, nausea, and liver toxicity, resulting in less than ideal long-term efficacy. Therefore, there is an urgent need to develop new AD therapeutic drugs that can improve AD symptoms and change the course of the disease.

[0005] AD is a disease caused by multiple factors, and its pathogenesis is complex and has not yet been fully elucidated. However, studies have shown that the decrease in acetylcholine levels in the patient's brain, excessive production and deposition of β-amyloid protein, platelet aggregation in cerebral blood vessels, metal ion metabolism disorders, and Ca 2+ Various factors play an important role in the pathogenesis of AD, including imbalance, neurofibrillary tangles caused by tau protein hyperphosphorylation, excessive glutamate receptor activity, oxidative stress producing a large number of reactive oxygen species (ROS) and free radicals, and neuroinflammatory reactions. In response to the above-mentioned pathogenic factors, researchers have adopted the traditional "one drug, one target" drug design strategy and discovered a large number of drugs with high activity and selectivity for a certain target, such as cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists. However, these drugs have problems such as a single target, more toxic side effects in clinical use, and poor long-term efficacy in AD patients.

[0006] At present, two monoamine oxidases have been identified and characterized in the human body, including two subtypes, MAO-A and MAO-B, which are mainly responsible for the oxidative deamination of biogenic amines and monoamine neurotransmitters such as serotonin, dopamine, norepinephrine and phenylethylamine to regulate their concentrations and metabolism in the brain and peripheral tissues. MAO-B is mainly distributed in the outer membrane of mitochondria of glial cells, and uses flavin adenine dinucleotide (FAD) as a coenzyme factor. It is the main enzyme in the brain for the oxidative deamination of dopamine. Recent studies have found that the expression of MAO-B in the brains of AD or PD patients is abnormally increased. This enzyme can not only destroy cholinergic neurons, promote the formation of Aβ plaques and neurofibrillary tangles, but also significantly reduce the dopamine content in the brain; in addition, while MAO-B catalyzes deamination, it also produces H2O2, and the generated H2O2 can react with endogenous Cu 2+ , Fe 2+ Plasma generates hydroxyl radicals through the Fenton reaction, which can damage lipids, proteins and nucleic acids, thus causing mitochondrial dysfunction and ultimately leading to brain neuron cell death. Therefore, inhibiting the deamination of MAO-B can not only increase the content of dopamine in the brain, but also achieve the effects of anti-oxidative stress and neuroprotection by reducing the production of free radicals and reactive oxygen species; other studies have found that inhibiting MAO-B can also increase the content of phenylethylamine in the brain, which can stimulate the release of dopamine and inhibit the reuptake of dopamine. Therefore, the discovery of selective inhibitors of MAO-B is of great significance for the treatment and / or prevention of diseases related to the nervous system.

[0007] In recent years, with the continuous clarification of the pathogenic mechanism of neurodegenerative diseases, it has been found that the occurrence and development of neurodegenerative diseases are characterized by multiple mechanisms and multiple factors. Different mechanisms are interrelated and influence each other, forming a complex network regulation system in the occurrence and development of such diseases. Obviously, the development of therapeutic drugs that can act on multiple links in the pathological process of neurodegenerative diseases at the same time is an inevitable choice at present. Based on the above results, researchers proposed a "multi-target-oriented drug" strategy to develop drugs against neurodegenerative diseases. The so-called "multi-target drug" refers to a single chemical entity that acts on multiple targets in the disease network at the same time, and the effect on each target can produce a synergistic effect, so that the total effect is greater than the sum of each single effect. The main difference between multi-target drugs and multi-drug combined use and compound drugs is that they can reduce the dosage, improve the therapeutic effect, avoid interactions between drugs and the resulting toxic and side effects, have uniform pharmacokinetic properties, and are easy to use. Therefore, the development of anti-neurodegenerative disease therapeutic drugs with new chemical structures, new mechanisms of action, multi-target effects, and low toxic and side effects is an important direction at present. Summary of the invention

[0008] The present invention aims to disclose a class of hydroxyphenylpyridazine Mannich base compounds (I) and pharmaceutically acceptable salts thereof.

[0009] Another object of the present invention is to disclose a method for preparing the hydroxyphenylpyridazine Mannich base compound (I) and its pharmaceutically acceptable salt.

[0010] Another object of the present invention is to disclose a pharmaceutical composition comprising the hydroxyphenylpyridazine Mannich base compound (I) and a pharmaceutically acceptable salt thereof.

[0011] Another object of the present invention is to disclose that the hydroxyphenylpyridazine Mannich base compound (I) and its pharmaceutically acceptable salt have multi-target effects and can be used for preparing drugs for treating and / or preventing nervous system related diseases, including but not limited to vascular dementia, Alzheimer's disease, frontotemporal dementia, prion disease, Lewy body dementia, Parkinson's disease, Huntington's disease, HIV-related dementia, multiple sclerosis, amyotrophic lateral sclerosis, neuropathic pain, ischemic stroke, hemorrhagic stroke and nerve damage caused by brain trauma.

[0012] The general chemical structure formula of the hydroxyphenylpyridazine Mannich base compound (I) disclosed in the present invention is:

[0013]

[0014] In the formula: R1, R2 and R3 each independently represent H, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, halogen, R1, R2 and R3 are in any possible position of their benzene ring; R4 and R5 each independently represent C1-C6 alkyl, when NR4R5 forms a ring, it represents tetrahydropyrrolyl, morpholinyl, piperidinyl, 4-thiopiperidinyl, piperazinyl, C1-C6 alkyl-substituted piperazinyl, 4-benzylpiperazinyl; R6 represents H, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, R7CONH, CN, halogen, NR8R9 or -CH2NR4R5; R7 represents C1~C6 alkyl; R8 and R9 each independently represent H, C1~C6 alkyl, but R8 and R9 do not represent H at the same time; when NR8R9 forms a ring, it represents tetrahydropyrrolyl, morpholinyl or piperidinyl; R6 and -CH2NR4R5 are in any possible position of their corresponding benzene rings; the "halogen" refers to F, Cl, Br or I.

[0015] The hydroxyphenylpyridazine Mannich base compound (I) disclosed in the present invention can be prepared by the following method: using the corresponding 3-chloro-6-hydroxyphenylpyridazine Mannich base compound (1) as a starting material, reacting with a benzyl alcohol compound (2) in a solvent under alkaline conditions to obtain the corresponding hydroxyphenylpyridazine Mannich base compound (I), and the reaction formula is as follows:

[0016]

[0017] Wherein: the definitions of R1 to R6 are the same as the general chemical structure formula of the hydroxyphenylpyridazine Mannich base compound (I).

[0018] For the above-mentioned synthetic route, its specific preparation method is described as follows:

[0019] The solvent used in the reaction is: ether, tetrahydrofuran, 2-methyltetrahydrofuran, dichloromethane, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol dimethyl ether, 1,4-dioxane, benzene, toluene or acetonitrile, and the preferred solvent is: N,N-dimethylformamide, dichloromethane, tetrahydrofuran or toluene; the base used in the reaction is: alkali metal hydride, alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal carbonate or alkaline earth metal carbonate, and the preferred base is: lithium hydride , sodium hydride, potassium hydroxide or potassium carbonate; 3-chloro-6-hydroxyphenylpyridazine Mannich base compound (1): benzyl alcohol compound (2): the molar feed ratio of the base is 1.0: 1.0-5.0: 1.5-6.0, preferably the molar feed ratio is 1.0: 1.0-3.0: 2.0-4.0; the reaction temperature is 0°C to 120°C, preferably the reaction temperature is room temperature to 100°C; the reaction time is 1 to 72 hours, preferably the reaction time is 2 to 24 hours.

[0020] The hydroxyphenylpyridazine Mannich base compound (I) obtained by the above method can be reacted with any suitable acid by conventional salt-forming methods to obtain its pharmaceutically acceptable salt, wherein the acid is: hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, aminosulfonic acid, C 1-6 Fatty carboxylic acids (such as formic acid, acetic acid, propionic acid, etc.), trifluoroacetic acid, stearic acid, oxalic acid, benzoic acid, phenylacetic acid, salicylic acid, maleic acid, fumaric acid, succinic acid, tartaric acid, citric acid, malic acid, lactic acid, hydroxymaleic acid, pyruvic acid, glutamic acid, ascorbic acid, lipoic acid, C 1-6 Alkylsulfonic acid (such as methanesulfonic acid, ethylsulfonic acid, etc.), camphorsulfonic acid, naphthalenesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid or 1,4-butanedisulfonic acid.

[0021] The starting material of the present invention, 3-chloro-6-hydroxyphenylpyridazine Mannich base compound (1), can be prepared by common techniques in the art, including but not limited to the methods disclosed in the following documents: 1. Yichun Shi, et al. Eur. J. Med. Chem. 2022, 230, 114098; 2. Binglun Lam. US4340733.

[0022] The pharmaceutical composition disclosed in the present invention comprises a therapeutically effective amount of one or more hydroxyphenylpyridazine Mannich base compounds (I) or pharmaceutically acceptable salts thereof, and the pharmaceutical composition may further contain one or more pharmaceutically acceptable carriers or excipients. The "therapeutically effective amount" refers to the amount of a drug or agent that causes a biological or medical response in a tissue, system or animal targeted by a researcher or doctor; the "composition" refers to a product formed by mixing more than one substance or component; the "pharmaceutically acceptable carrier" refers to a pharmaceutically acceptable substance, composition or carrier, such as a liquid or solid filler, diluent, excipient, solvent or encapsulating material, which carries or transports a certain chemical substance. The ideal ratio of the pharmaceutical composition provided by the present invention is that the hydroxyphenylpyridazine Mannich base compound (I) or pharmaceutically acceptable salt thereof as an active ingredient accounts for 2% to 99.5% of the total weight.

[0023] The hydroxyphenylpyridazine Mannich base compounds (I) and pharmaceutically acceptable salts thereof disclosed in the present invention were screened for the following biological activities:

[0024] (1) Inhibitory activity of hydroxyphenylpyridazine Mannich base compounds (I) against monoamine oxidase B

[0025] Recombinant human MAO-B was prepared into a 75μg / mL sample solution using 100mM pH 7.4 potassium phosphate buffer. 20μL of the test compound solution and 80μL of monoamine oxidase were added to a black 96-well plate, mixed, and incubated at 37°C in a dark place for 15min. 200μM Amplex Red reagent, 2U / mL horseradish peroxidase, and 2mM benzylamine were added to initiate the reaction, and incubated at 37°C for 20min. On a multifunctional microplate reader, the fluorescence emission intensity at 590nm was measured with a fixed excitation wavelength of 545nm, and potassium phosphate buffer was used instead of MAO-B as a blank; the inhibition rate of the compound inhibiting monoamine oxidase was calculated as follows: 100-(IF i ) / (IF c )*100, in the formula, IF i and IF cThe difference between the fluorescence intensity in the presence of inhibitors and in the absence of inhibitors and the blank fluorescence intensity. Each compound was tested in 3 replicates each time, and each group of experiments was repeated three times independently. Five to six concentrations of the compound were selected to determine their enzyme inhibition rate, and the negative logarithm of the molar concentration of the compound was linearly regressed with the enzyme inhibition rate. The molar concentration at which the inhibition rate was 50% was the IC of the compound. 50 The results show that the hydroxyphenylpyridazine Mannich base compounds (I) disclosed in the examples of the present invention have significant inhibitory effects on MAO-B, and their IC 50 The MAO-B inhibitory activity of the corresponding compounds was significantly reduced when the "benzyloxy" at the 3-position of the pyridazine nucleus of the hydroxyphenylpyridazine Mannich base compound (I) was replaced by "H" or "OH" and the substituent at the 6-position of the pyridazine nucleus remained unchanged. 50 The values ​​were all greater than 50.0 μM; and the MAO-B inhibition IC values ​​of the obtained 2-benzyl-6-hydroxyphenylpyridazine-3-one Mannich base compounds were all greater than 50.0 μM; and the "benzyl" of the 3-benzyloxy group in the hydroxyphenylpyridazine Mannich base compound (I) was shifted to the 2-N of the pyridazine mother nucleus. 50 The values ​​were all greater than 50.0 μM.

[0026] (2) Antioxidant activity of hydroxyphenylpyridazine Mannich base compounds (I) (ORAC-FL method)

[0027] The determination was carried out according to the method reported in the literature (Qiang, XM et al. Eur. J Med. Chem. 2014, 76, 314-331), namely: 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) was prepared into a 10-80 μmol / L solution with a pH 7.4 PBS buffer, fluorescein was prepared into a 250 nmol / L solution with a pH 7.4 PBS buffer, and 2,2'-azobisisobutylamidine dihydrochloride (AAPH) was prepared into a 40 mmol / L solution with a pH 7.4 PBS buffer before use. Add 50-10 μmol / L compound solution and fluorescein solution to a 96-well plate, mix, incubate at 37°C for 15 min, add AAPH solution to make the total volume of each well 200 μL, mix, and immediately place in Varioskan Flash Multimode Reader (ThermoScientific) instrument, and continuously measure for 90 min at an excitation wavelength of 485 nm and an emission wavelength of 535 nm. Calculate the area under the fluorescence decay curve AUC, where 1-8 μmol / L Trolox is used as the standard, and no sample is added as the blank. The antioxidant activity results of the compound are expressed as the equivalent of Trolox, and the calculation formula is: [(AUC Sample-AUC blank) / (AUCTrolox-AUC blank)]×[(concentration of Trolox / concentration of sample)], each compound is measured in 3 replicates each time, and each group of experiments is repeated three times independently. The results of the test show that the antioxidant activity of the hydroxyphenylpyridazine Mannich base compounds (I) disclosed in the examples of the present invention is 1.15 to 3.3 times that of Trolox, indicating that the compounds have strong antioxidant activity. Further studies have found that when the "OH" on the 6-position benzene ring of the pyridazine parent nucleus in the hydroxyphenylpyridazine Mannich base compounds (I) in the examples is replaced with "H" and the 3-position benzyloxy group of the pyridazine parent nucleus remains unchanged, the antioxidant activity of the corresponding compounds obtained is significantly reduced, and the antioxidant activity is reduced by at least 1.6-4.8 times, indicating that the "OH" on the 6-position benzene ring of the pyridazine parent nucleus has a relatively important influence on the antioxidant activity of the compound.

[0028] (3) Complexation of Hydroxyphenylpyridazine Mannich Base Compounds (I) with Metal Ions

[0029] CuCl2·2H2O, ZnCl2, FeSO4, AlCl3 and the test compound were dissolved in methanol to prepare a 75μmol / L solution, 100μL of the test compound solution and 100μL of the metal ion solution were added to a 96-well plate, mixed, and allowed to stand at room temperature for 30min. The ultraviolet absorption curve of the mixture in the range of 200-600nm was recorded on a Varioskan Flash Multimode Reader, and the red shift phenomenon and the intensity of the maximum absorption peak of the metal ion and the test compound mixture were observed with 100μL of the test compound solution and 100μL of the methanol mixture as controls. The measurement results show that the hydroxyphenyl pyridazine Mannich base compound (I) disclosed in the embodiment of the present invention exhibits a complexing effect on the above metal ions; and the "OH" on the 6-position benzene ring of the pyridazine parent nucleus in its structure is replaced by "H", and the corresponding compound obtained has almost no complexing effect with the above metal ions (the maximum absorption peak intensity of the test compound and the metal ion mixture has no obvious change, and the maximum absorption peak has no red shift phenomenon). This study shows that the "OH" on the 6-position benzene ring of the pyridazine parent nucleus in hydroxyphenylpyridazine Mannich base compounds (I) has a significant effect on the metal ion complexation of the compound.

[0030] (4) Inhibitory activity of hydroxyphenylpyridazine Mannich base compounds (I) on neuroinflammation

[0031] (a) Effects of compounds and lipopolysaccharide (LPS) on BV-2 cell viability

[0032] BV-2 cells in the logarithmic growth phase were prepared into a cell suspension and inoculated into a 96-well plate, and cultured in a cell culture incubator at 37°C and 5% CO2 for 24 h. After the cells adhered to the wall, 90 μL of fresh serum-free culture medium was replaced, and 10 μL of the test compound at each concentration was added for pre-incubation for 30 min. Three parallel wells were set for each concentration, and a blank control group was set up at the same time; then LPS was added or not, and cultured in a cell culture incubator at 37°C and 5% CO2 for another 24 h. MTT solution was added, and the cells were incubated at 37°C for 4 h. The supernatant was discarded, and 200 μL of DMSO solution was added to each well. After slight shaking for 10 min, the OD value was measured at 490 nm using a microplate reader, and the mean OD value measured at different concentrations of each test sample was calculated, and the cell survival rate was calculated according to the following method: Cell survival rate (%) = mean OD value of the treatment group / mean OD value of the control group × 100%. The test results show that all hydroxyphenylpyridazine Mannich base compounds (I) disclosed in the examples of the present invention show no cytotoxicity (inhibition rate less than <10%) at a concentration not exceeding 30 μM.

[0033] (b) Effects of compounds on NO release from BV-2 cells induced by LPS

[0034] BV-2 cells in the logarithmic growth phase were prepared into a cell suspension and inoculated into a 96-well plate, and cultured in a cell culture incubator at 37°C and 5% CO2 for 24 h. After the cells adhered to the wall, 90 μL of fresh serum-free culture medium was replaced, and 10 μL of the test compound at each concentration was added for pre-incubation for 30 min. Three parallel wells were set for each concentration, and a blank control group was set up at the same time. LPS (1.0 μg / ml) was then added for stimulation, and the cells were cultured in a cell culture incubator at 37°C and 5% CO2 for another 24 h. The cell culture supernatants of the different treatment groups were taken, and an equal volume of Griess reagent I and an equal volume of Griess reagent II were added. The plates were reacted at room temperature in the dark for 10 min, and the absorbance was measured at 540 nm to detect the NO level in the cell supernatant (the specific operation was carried out according to the instructions of the NO detection kit). The test results show that all the hydroxyphenylpyridazine Mannich base compounds (I) disclosed in the examples of the present invention show a strong inhibitory effect on LPS-induced NO production in BV-2 cells in the concentration range of 0.5 μM to 25 μM (the inhibition rate at a concentration of 10.0 μM is more than 31.5%), and have an obvious dose-effect relationship; indicating that the hydroxyphenylpyridazine Mannich base compounds (I) have significant anti-neuroinflammatory activity. DETAILED DESCRIPTION

[0035] The present invention can be further described by the following examples, however, the scope of the present invention is not limited to the following examples. It will be appreciated by those skilled in the art that various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention.

[0036] Example 1 General method for preparing hydroxyphenylpyridazine Mannich base compounds (I)

[0037] Benzyl alcohol compound (2) (4.0 mmol), sodium hydride (6.0 mmol) and tetrahydrofuran (30 ml) were added to a reaction flask, stirred at room temperature for 10 minutes, then 3-chloro-6-hydroxyphenylpyridazine Mannich base compound (1) (2.0 mmol) was added, and the reaction was continued at room temperature for 2.0 hours to 20.0 hours (the reaction progress was tracked by TLC); after the reaction, the solvent was evaporated under reduced pressure, deionized water (40 ml) was added to the residue, the pH of the solution was adjusted to 3-5 with acid, and then extracted with ethyl acetate (80 ml) three times, the organic layers were combined and washed with saturated sodium chloride aqueous solution, dried over anhydrous sodium sulfate, filtered, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: dichloromethane-petroleum ether = 15:1 v / v) to obtain the corresponding hydroxyphenylpyridazine Mannich base compound (I) with a yield of 35.2%-70.6%. The chemical structures of the compounds were 1 H-NMR, 13C-NMR and ESI-MS confirmed that the purity of the obtained target product was greater than 96.0% as determined by HPLC. The structure of the target product prepared by the above general method is as follows:

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] Some compounds 1 H-NMR and 13 C-NMR data are as follows:

[0046]

[0047] 1 HNMR(CDCl3):13.32(s,1H),8.16(d,J=9.4Hz,1H),7.83(d,J=7.6Hz,1H),7.40-7.31(m,1H),7.18-7 .12(m,4H),6.93(t,J=7.6Hz,1H),5.56(s,2H),3.86(s,2H),2.66(s,4H),1.70(s,4H),1.52(s,2H);

[0048]

[0049] 1 HNMR(CDCl3):13.46(s,1H),8.32(d,J=9.4Hz,1H),8.09(s,1H),7.44-7.30(m,1H),7.26-7.13( m,4H),7.04(d,J=8.4Hz,1H),5.53(s,2H),3.70(s,2H),2.65(s,4H),1.76(s,4H),1.54(s,2H);

[0050]

[0051] 1HNMR(CDCl3):13.43(s,1H),8.22(d,J=9.4Hz,1H),7.81(s,1H),7.41-7.31(m,1H),7.26-7.12(m,3H),7.06(d,J=9 .4Hz,1H),5.56(s,2H),3.75(s,2H),3.50(s,2H),2.56(s,4H),2.46(s,4H),1.63(s,4H),1.61(s,4H),1.46(s,4H). 13 CNMR(CDCl3):162.9,155.9,155.6,150.3,150.2,133.7,131.7,131.1,130.1,127.7,124. 4,122.5,121.9,117.4,117.3,116.9,67.5,63.1,61.3,54.2,53.8,25.7,25.5,24.1,23.9;

[0052]

[0053] 1 HNMR(CDCl3):13.51(s,1H),8.26(d,J=9.4Hz,1H),7.88(d,J=2.2Hz,1H),7.35(ddd,J=11.0,7.6,2.2Hz,1H) ,7.26-7.13(m,3H),7.10(d,J=9.4Hz,1H),5.55(s,2H),3.78(s,2H),3.54(s,2H),2.41(s,6H),2.36(s,6H).

[0054] Example 2 General method for preparing hydroxyphenylpyridazine Mannich base compound (I) by acid salt formation

[0055] In a reaction flask, 1.0 mmol of the hydroxyphenylpyridazine Mannich base compound (I) obtained in Example 1 and 25 ml of methanol were added, stirred evenly, and then 3.0 mmol of the corresponding acid was added. After stirring at room temperature for 30 minutes, the solvent was evaporated under reduced pressure, and the residue was purified to obtain a salt of the hydroxyphenylpyridazine Mannich base compound (I). The chemical structure of the salt is shown in FIG. 1 The results were confirmed by H NMR and ESI-MS.

Claims

1. A class of hydroxyphenylpyridazine Mannich base compounds and pharmaceutically acceptable salts thereof, characterized in that The chemical structure of this type of compound is shown in (I): In the formula: R1, R2 and R3 each independently represent H, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, halogen, R1, R2 and R3 are in any possible position of their benzene ring; R4 and R5 each independently represent C1-C6 alkyl, or when NR4R5 forms a ring, represent tetrahydropyrrolyl, morpholinyl, piperidinyl, 4-thiopiperidinyl, piperazinyl, C1-C6 alkyl-substituted piperazinyl, 4-benzylpiperazinyl; R6 represents H, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, R7CONH, CN, halogen, NR8R9 or -CH2NR4R5; R7 represents C1-C6 alkyl; R8 and R9 each independently represent H, C1-C6 alkyl, but R8 and R9 do not represent H at the same time, or when NR8R9 forms a ring, it represents tetrahydropyrrolyl, morpholinyl or piperidinyl; R6 and -CH2NR4R5 are in any possible position of their corresponding benzene rings; the "halogen" refers to F, Cl, Br or I.

2. The hydroxyphenylpyridazine Mannich base compound or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that R1, R2 and R3 each independently represent H, methyl, methoxy, methylthio, F or Cl, and R1, R2 and R3 are in any possible position of their benzene ring; R4 and R5 each independently represent methyl, ethyl, or when NR4R5 forms a ring, represent tetrahydropyrrolyl, morpholinyl, piperidinyl, 4-thiopiperidinyl, piperazinyl, 4-methylpiperazinyl, 4-benzylpiperazinyl; R6 represents H, methyl, methoxy, CH3CONH, CN, F, Cl, dimethylamino, -CH2N(CH3)2, tetrahydropyrrolyl, 3. The hydroxyphenylpyridazine Mannich base compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 2, characterized in that The pharmaceutically acceptable salts are prepared by reacting such hydroxyphenylpyridazine Mannich base compounds with hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, aminosulfonic acid, C 1-6 Fatty carboxylic acids, trifluoroacetic acid, stearic acid, pamoic acid, oxalic acid, benzoic acid, phenylacetic acid, salicylic acid, maleic acid, fumaric acid, succinic acid, tartaric acid, citric acid, malic acid, lactic acid, hydroxymaleic acid, pyruvic acid, glutamic acid, ascorbic acid, lipoic acid, C 1-6 Salts of alkylsulfonic acid, camphorsulfonic acid, naphthalenesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid or 1,4-butanedisulfonic acid.

4. A method for preparing a hydroxyphenylpyridazine Mannich base compound or a pharmaceutically acceptable salt thereof as claimed in any one of claims 1 to 3, characterized in that The compound can be prepared by the following method: Wherein: R1 to R6 are defined in the same manner as the general chemical structure of the hydroxyphenylpyridazine Mannich base compound (I); The corresponding 3-chloro-6-hydroxyphenylpyridazine Mannich base compound (1) is used as a starting material, and reacts with a benzyl alcohol compound (2) in a solvent under alkaline conditions to obtain the corresponding hydroxyphenylpyridazine Mannich base compound (I); and then reacts with an acid through a conventional salt-forming method to obtain a pharmaceutically acceptable salt thereof.

5. The method for preparing the hydroxyphenylpyridazine Mannich base compound or a pharmaceutically acceptable salt thereof as claimed in claim 4, characterized in that The base used in the reaction is: alkali metal hydride, alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal carbonate or alkaline earth metal carbonate; the solvent used in the reaction is: ether, tetrahydrofuran, 2-methyltetrahydrofuran, dichloromethane, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol dimethyl ether, 1,4-dioxane, benzene, toluene or acetonitrile.

6. The method for preparing the hydroxyphenylpyridazine Mannich base compound or a pharmaceutically acceptable salt thereof as claimed in claim 4, characterized in that The molar feed ratio of 3-chloro-6-hydroxyphenylpyridazine Mannich base compound (1): benzyl alcohol compound (2): base is 1.0: 1.0-5.0: 1.5-6.

0.

7. The method for preparing the hydroxyphenylpyridazine Mannich base compound or a pharmaceutically acceptable salt thereof as claimed in claim 4, characterized in that The reaction temperature is 0°C to 120°C; the reaction time is 1 to 72 hours.

8. A pharmaceutical composition characterized in that The invention comprises the hydroxyphenylpyridazine Mannich base compound or a pharmaceutically acceptable salt thereof as claimed in any one of claims 1 to 3 and one or more pharmaceutically acceptable carriers or excipients.

9. Use of the hydroxyphenylpyridazine Mannich base compound or a pharmaceutically acceptable salt thereof as claimed in any one of claims 1 to 3 in the preparation of a medicament for treating and / or preventing a nervous system-related disease, wherein the nervous system-related disease is vascular dementia, Alzheimer's disease, frontotemporal dementia, prion disease, Lewy body dementia, Parkinson's disease, Huntington's disease, HIV-related dementia, multiple sclerosis, amyotrophic lateral sclerosis, neuropathic pain, ischemic stroke, hemorrhagic stroke and nerve damage caused by brain trauma.

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