CN114853715B - Organic nitrite donor ketal type prodrug, preparation method and medical application thereof - Google Patents

Abstract

The invention relates to the field of pharmaceutical chemistry, in particular to organic nitrite containing 1-nitromethyl-2-phenylethene skeleton

A donor ketal type prodrug, a preparation method thereof and medical application of a medicinal composition of the compound I in preventing or treating cerebral ischemia, myocardial ischemia and pulmonary arterial hypertension. Compared with the organic nitrite donor compound VI which is designed and synthesized previously, the organic nitrite donor ketal type prodrug I has better plasma stability, and the ketal type prodrug I strategy can be further improved

Plays an ischemic protecting role and improves the survival rate of oxygen glucose deprivation/reperfusion (OGD/R) primary neuron cells. Simultaneous pharmacokinetic studies indicate that ketal prodrugs

The donor has better pharmacokinetic behavior. In addition, the prodrug strategy can obviously reduce the cerebral infarction volume and the cerebral water content of MCAO rats, accelerate the proliferation of endothelial cells of ischemic brain tissues of rats and promote the generation of new blood vessels.

Description

Organic nitrite donor ketal type prodrug, preparation method and medical application thereof

Technical Field

The invention relates to the field of pharmaceutical chemistry, in particular to an organic nitrite containing a 1-nitromethyl-2-phenylethene skeleton

Preparation method of donor ketal type prodrug (compound I), medicinal composition containing ketal type prodrug (compound I) and medical application thereof, in particular application in preparing medicines for preventing or treating cerebral ischemia, myocardial ischemia and pulmonary arterial hypertension.

Background

In recent years, research has shown thatSodium nitrate (NaNO) ₂ ) Has good treatment and protection effects on some cardiovascular and cerebrovascular diseases, especially ischemic diseases. Clinical studies show that intravenous drip of low dose sodium nitrite is truly effective and well tolerated for patients with acute ischemic stroke, and the side effects are only transient blood pressure drop and trace rise (5%) of methemoglobin level, and can disappear after stopping the drug.

Myocardial ischemia is one of the main inducing factors of myocardial infarction, and sodium nitrite has remarkable effect of resisting myocardial ischemia. The myocardial ischemia mice can reduce the volume of myocardial infarction by about 48% by orally taking sodium nitrite. The myocardial ischemia mice were injected with sodium nitrite ventricular ly to reduce the infarct volume by 67%. The volume of myocardial infarction can be reduced by 52.7% and 66% respectively by injecting sodium nitrite into abdominal cavity 24h before myocardial ischemia or immediately before reperfusion. The low-dosage sodium nitrite is instilled into the vein of the patient suffering from myocardial ischemia, so that the myocardial ischemia/reperfusion injury of the patient can be relieved, but the normal tissue is not affected.

In addition to heart and brain ischemic diseases, sodium nitrite can also be used for treating ischemia/reperfusion injury of liver, kidney and limbs. Sodium nitrite inhibits cell necrosis and apoptosis of liver ischemic mice, and shows a strong liver protection effect. In a mouse kidney ischemia model, sodium nitrite also plays a good protective role by dilating blood vessels. In the mouse hind limb vein ischemia model, sodium nitrite can stimulate endothelial cell growth in a time-dependent manner, so that the blood vessel density of an ischemia area is improved, and the blood flow is increased.

The action mechanism research of the sodium nitrite discovers that the NO scavenger carbon-PTIO (abbreviated as PTIO) can inhibit the anti-ischemia/reperfusion protection activity of the sodium nitrite, and the treatment effect of the sodium nitrite is provided with NO dependence. In clinical experiments, the S-nitrosothiols in blood plasma are obviously increased after intravenous injection of sodium nitrite, which indicates that the sodium nitrite is reduced to NO and then reacts with thiols to generate nitrosothiols.

The mechanism research of the reduction of sodium nitrite into NO shows that in the low-oxygen and low-pH environment caused by ischemia,

can be reduced to NO by deoxyhemoglobin (deoxyHb), xanthine Oxidoreductase (XOR), endothelial nitric oxide synthase (eNOS) and the like, and has multiple therapeutic effects of vasodilation, increased blood flow, free radical removal, antioxidation, promotion of angiogenesis at ischemic sites and the like; in normal oxygen-containing tissue, +.>

Oxidized to harmless->

Is discharged outside. Thus, NO ₂ ^– Are considered prodrugs of NO in ischemic, hypoxic tissue.

Although sodium nitrite has shown good effect in treating ischemic diseases in various animals, it can be rapidly metabolized after entering the circulation of human body, and the half-life period is only 25-30 minutes. In addition, large doses of sodium nitrite were administered without ischemia protection. The reason for this is probably that high concentration of sodium nitrite generates a large amount of NO in a short time, and superoxide anion radical

React to form peroxynitrite (ONOO) with stronger oxidizing ability ^- ) Resulting in toxic and side effects such as protein nitration and DNA damage. Furthermore, frequent administration of sodium nitrite may cause excessive Na ⁺ Intake adversely affects the cardiovascular system.

Disclosure of Invention

Research and discovery of small organic molecules

Donor compound, which is allowed to release a small amount of +.>

Not only has important theoretical significance, but also has potential clinical application value.

Based on the findings, a series of organic nitrite donor compounds are designed and synthesized, and have good therapeutic effects in preventing or treating cerebral ischemia, myocardial ischemia and pulmonary arterial hypertension. Nevertheless, some problems remain with the presently synthesized organic nitrite donor compounds. Since previous organic nitrite donors such as compound VI have an α, β -unsaturated ketone (Michael acceptor) structure that can bind to a variety of nucleophiles present endogenously (e.g., in plasma), stability and pharmacokinetic behavior (PK) of compound VI are not ideal. Although compound VI showed better in vitro cerebral ischemia protective activity, the substituents on the aromatic ring did not improve its stability. Thus, there remains a need to further modify existing organic nitrite donors to further improve stability and pharmacokinetic behavior while ensuring activity.

The tissue/cell microenvironment of the ischemic site is characterized by being slightly acidic (pH 5.5-5.8) compared to the normal microenvironment. In the process of drug design, active groups are masked, and acid sensitive groups (such as ketal/aldehyde, imine, hydrazone, acylhydrazone and the like) are introduced to prepare prodrugs, so that the prodrugs can be selectively released in an acid environment while having certain stability. In light of this, we contemplate protecting the ketocarbonyl group in the existing organic nitrite donor VI structure with a glycol fragment in ketal form to form a prodrug, which is expected to have improved stability, particularly under the action of nucleophiles; in addition, removal of the protecting group from the ketal structure under acidic conditions (in ischemic/hypoxic tissue) releases the original carbonyl group, i.e., restores the structure of the original drug compound VI, and further releases

Thereby achieving the purpose of selectively releasing at the ischemia/hypoxia site (figure 1).

Against this background, the present invention provides an organic compound containing a 1-nitromethyl-2-phenylethene skeleton

Donor ketal prodrugs (Compound I) and methods for preparing Compound I, pharmaceutical compositions containing the Compound, and pharmaceutical compositions containing the CompoundAcceptable salts and medical application thereof.

The technical scheme is as follows: the compound disclosed by the invention is an organic compound containing a 1-nitromethyl-2-phenylethene skeleton

A compound ketal-type prodrug of the donor type (compound I), and pharmaceutically acceptable salts thereof:

compound I: (E) -2-nitromethyl-3-phenyl-1- (3- (trifluoromethyl) phenyl) prop-2-en-1-ketal;

the invention also provides a preparation method of the compound I.

The designed organic nitrite donor ketal type prodrug (compound I) can be prepared by the following steps:

the synthesis of target compound I includes the first reaction of dibenzylamine (compound II) and 3-trifluoromethyl propiophenone (compound III) in the presence of ammonium persulfate to obtain key intermediate IV, the subsequent bromination of N-bromosuccinimide (NBS) to obtain intermediate V, and subsequent reaction with silver nitrite (AgNO) ₂ ) And (3) reacting to obtain a compound VI, and finally, carrying out reflux water with anhydrous benzene serving as a solvent under the catalysis of p-toluenesulfonic acid (p-TsOH) and triethyl orthoformate by the compound VI and ethylene glycol to obtain the target compound I.

The invention also provides application of the compound and the pharmaceutical composition in preparing medicines for preventing or treating cardiovascular and cerebrovascular diseases and pulmonary arterial hypertension, wherein the cardiovascular and cerebrovascular diseases are cerebral ischemia, cerebral apoplexy, myocardial ischemia, myocardial infarction, angina pectoris, arrhythmia or coronary heart disease.

The dosage forms of the pharmaceutical composition of the present invention may be prepared by those skilled in the art according to conventional methods in the pharmaceutical arts. For example, the active ingredient is admixed with one or more carriers (also known as excipients) and then formulated into desired dosage forms, including tablets, capsules, granules, aerosols; can also be made into intravenous injection or intravenous injection freeze-dried agent according to the conventional production method of injection.

The beneficial effects are that: compared to the previously designed and synthesized organic nitrite donor compound VI, the organic nitrite donor ketal-type prodrug (compound I) of the present invention has the following excellent properties: (1) Compound I has better plasma stability. (2) The compound I has higher stability in the presence of in vitro mercapto-containing nucleophile and can be slowly released in a dose-dependent manner

(3) Compound I can be released slowly in vivo>

Generates NO with effective concentration, exerts remarkable anti-cerebral ischemia activity, and the ketal prodrug strategy can further improve +.>

Plays a role in ischemia protection. (4) Ketal prodrug compound I can further increase survival of oxygen glucose deprivation/reperfusion (OGD/R) primary neuronal cells. (5) Pharmacokinetic studies indicate that ketal pro-drug form +.>

Donor I had better PK behaviour. (6) The compound I can obviously reduce the cerebral infarction volume and the cerebral water content of MCAO rats. (7) Compound I can significantly improve the neurobehavioral function of rats. (8) The compound I can accelerate the proliferation of rat ischemic brain tissue endothelial cells, promote the generation of new blood vessels, and remarkably improve the cerebral ischemia activity of the compound VI.

Drawings

FIG. 1 is a design concept of ketal-type prodrugs (Compound I);

FIG. 2 is the plasma stability of a ketal-type prodrug (Compound I);

FIG. 3 is the stability of ketal-type prodrugs (Compound I) in the presence of nucleophiles;

FIG. 4 is the primary neuronal protection effect of ketal-type prodrugs (Compound I) in the OGD/R model;

FIG. 5 is nitrite ion release in OGD/R primary neurons of ketal type prodrugs (Compound I);

table 1 is an in vitro evaluation of antiplatelet aggregation activity of ketal-type prodrugs (Compound I);

table 2 is the pharmacokinetic parameters of ketal-type prodrugs (compound I) in rats;

FIG. 6 is a graph of the concentration of ketal-type prodrug (Compound I) in rat plasma;

table 3 shows the results of the ketal-type prodrug (Compound I) distribution assay in plasma and brain tissue;

fig. 7 is an in vivo evaluation of anti-cerebral ischemia activity of ketal-type prodrugs (compound I).

Detailed Description

The following is a further detailed description of the present invention, by way of example, showing specific embodiments.

Example 1: (E) Preparation of (E) -2-Nitromethyl-3-phenyl-1- (3- (trifluoromethyl) phenyl) prop-2-en-1-ketal (Compound I)

(a) Sequentially combining (NH) ₄ ) ₂ S ₂ O ₈ Placing the tert-amyl alcohol and dibenzylamine into a schlenk bottle, and respectively adding 3-trifluoromethyl propiophenone and N ₂ Replacement, and reacting for 24-30h at 120 ℃; the reaction liquid gradually changes from white to yellow. After the completion of the reaction, the mixture was quenched with water, extracted with ethyl acetate (100 mL), and the organic layer was washed 3 times with water and saturated brine, dried over anhydrous sodium sulfate, concentrated, and purified by column chromatography (petroleum ether/ethyl acetate=100/1, v/v) to give compound IV. Product IV was a colorless oil, 75% yield. ¹ H NMR(300MHz,CDCl ₃ )δ8.00(s,1H),7.92(d,J＝7.7Hz,1H),7.81(d,J＝7.6Hz,1H),7.60(t,J＝7.7Hz,1H),7.43(d,J＝4.2Hz,4H),7.40-7.34(m,1H),7.16(s,1H),2.29(s,3H). ¹³ C NMR(75MHz,CDCl ₃ )δ197.75,143.13,139.32,136.55,135.41,132.52,131.11,130.68,129.74,128.92,128.80,128.55,128.05,128.00,126.22,126.17,126.12,126.07,125.57,14.21.

(b) Compound IV (222.1 mg,1.0mmol,1.0 eq) was dissolved in 50mL carbon tetrachloride, NBS (213.6 mg,1.2mmol,1.2 eq) and Azobisisobutyronitrile (AIBN) (1.6 mg,0.01mmol,0.01 eq) were added, and the reaction was heated to reflux under nitrogen protection, reacted for 24h and quenched with water. The carbon tetrachloride was removed by rotary evaporation, and then extracted with ethyl acetate, and the organic layer was washed 3 times with water and saturated brine, dried over anhydrous sodium sulfate, and concentrated to purify to give colorless oil V in 81% yield. ¹ H NMR(300MHz,CD ₃ OD)δ8.05-7.91(m,3H),7.74(t,J＝7.8Hz,1H),7.61(d,J＝6.9Hz,2H),7.49(q,J＝8.0,7.1Hz,3H),7.27(s,1H),4.60(s,2H). ¹³ C NMR(75MHz,CDCl ₃ )δ195.00,144.13,138.56,136.56,136.21,133.83,132.70,129.96,129.53,129.05,128.82,128.29,126.18,26.27.

(c) Allyl bromide V (0.85 mmol,1.0 eq) was dissolved in 25mL anhydrous diethyl ether, silver nitrite (390 mg,2.6mmol,3.0 eq) was added and reacted overnight protected from light. The reaction solution was filtered, the filtrate was concentrated, and column chromatography (petroleum ether/ethyl acetate=20/1, v/v) gave a colorless oil VI in 56% yield. ¹ H NMR(300MHz,CD ₃ OD)δ8.10(d,J＝8.2Hz,2H),7.96(d,J＝7.6Hz,1H),7.78(t,J＝7.7Hz,1H),7.67(s,1H),7.49(d,J＝5.2Hz,3H),7.44-7.36(m,2H),5.68(s,2H). ¹³ C NMR(75MHz,CDCl ₃ )δ197.31,151.36,140.42,135.66,135.49,133.72,133.16,132.56,131.88,131.80,131.69,131.64,131.59,128.96,74.26.ESI-MS(m/z):336.1[M+H] ⁺ .

(d) Compound VI (1.0 eq) was dissolved in 2mL benzene (super dry solvent), and ethylene glycol (2.0 eq), anhydrous p-toluene sulfonic acid (0.1 eq) and triethyl orthoformate (8.0 eq) were added in sequence, followed by reflux with water (Dean-Stark trap) at 80 ℃ for 24h. Then adding sodium bicarbonate aqueous solution for quenching, filtering to remove insoluble substances, extracting with ethyl acetate (10 mL×3), mixing organic layers, washing with saturated saline 3 times (10 mL×3), drying with anhydrous sodium sulfate, concentrating, and performing column chromatography(PE/ea=20/1, v/v) to give the target compound I in a yield of 10% as a colorless oil. ¹ H NMR(300MHz,CDCl ₃ )δ7.86(s,1H),7.78(d,J＝7.7Hz,1H),7.64(d,J＝7.7Hz,1H),7.53(t,J＝7.7Hz,1H),7.34(d,J＝3.3Hz,5H),7.09(s,1H),5.04(s,2H),4.14(m,2H),3.97(m,2H)； ¹³ C NMR(75MHz,CDCl ₃ ):δ141.99,137.10,136.60,136.31,129.79,129.16,129.11,128.63,128.52,128.20,127.79,126.91,125.07,123.07,65.43,65.02,64.78.ESI-MS(m/z):380.1[M+H] ⁺ .

Example 2: ketal prodrug (Compound I) plasma stability test

1. Test method

Compound I and compound VI were each dissolved in Niu Xiejiang (5% dmso to aid dissolution) at a concentration (200 μm), incubated at 37.4 ℃, sampled at intervals, and peak areas of the two compounds were recorded by HPLC for comparison, compound VI being a positive control.

2. Test results

The results are shown in FIG. 2. As a result, compound VI is found to be rapidly degraded in the plasma, and the degradation is completed within 2 hours; ketal prodrug I significantly improved the plasma stability of the drug substance. The compound I has good stability, and only 7.8% of the compound I is degraded within 24 hours; . These results suggest that ketal-type prodrugs have better plasma stability, significantly stronger than compound VI.

Example 3: stability of ketal-type prodrugs (compound I) in the presence of nucleophiles.

1. Test method

Equal concentrations of N-acetylcysteine (200. Mu.M) were incubated with Compound VI and Compound I, respectively, at 37.4℃and the concentrations of each compound were determined at each time point by the same method as described above.

2. Test results

As shown in fig. 3, compound VI can gradually degrade over time, while compound I has better stability, with little degradation in the presence of nucleophiles. These results demonstrate that protecting the carbonyl group in the α, β -unsaturated ketone structure of compound I can effectively reduce its ability to attack by nucleophiles, improving stability.

Example 4: OGD/R model primary neuron protection test

1. Test method

The OGD/R injury protection effect of compound I on primary neuronal cells in vitro will be studied. Before this, we found 24h before molding as the optimal dosing time point. We then selected different concentrations of compound VI and compound I, and tested the activity of the corresponding concentrations of compound in the OGD/R model, respectively.

2. Test results

As shown in fig. 4, both compound VI and compound I (0.1, 1 and 10 μm) increased the survival of neurons after OGD/R treatment in a dose-dependent manner compared to the OGD/R model group, wherein the ketal prodrug (compound I) was the most potent at high concentrations, with a survival of 75.6% better than the prodrug compound VI (70.9%) under the same conditions. In addition, these results suggest that ketal prodrug strategies may be enhanced

Plays a role in ischemia protection.

Example 5: nitrite ion release test in OGD/R primary neurons

1. Test method

Firstly, separating rat primary cortical neurons, establishing an OGD/R model, simulating in-vitro ischemia/reperfusion injury, and testing the compounds in the primary neuronal cells of the OGD/R model by using a Griess reagent method

Release level. After pre-incubation of compound (10. Mu.M) and primary neuronal cells for 24h, detecting +.f in cell lysate by OGD 2 h/R24 h>

Is a level of (c).

2. Test results

As shown in FIG. 5, both compounds VI and I can release higher concentrations in the OGD/R model primary neurons

Notably, the release amount of the target compound I is higher than VI, i.e. the ketal prodrug strategy can improve the +.>

The amount released, which may be related to the improved stability of the overall molecule and the permeant properties of compound I. The above results are consistent with OGD/R primary neuronal cell protection, suggesting that the activity of the compound is consistent with +.>

Related to release of (c).

Example 6: evaluation of in vitro anti-platelet aggregation Activity

1. Test method

Platelet Rich Plasma (PRP) and Platelet Poor Plasma (PPP) preparation: new Zealand white rabbits (the male and female half, nanjing qing mountain animal breeding farm) are fasted for 12-18 hours, 10% chloral hydrate solution is used for intraperitoneal injection for anesthesia, a polyethylene tube is inserted for blood collection after common carotid artery separation, the blood is injected into a siliconizing centrifuge tube containing 1/10 capacity of 3.8% sodium citrate solution, the blood and an anticoagulant are gently mixed, the mixture is centrifuged for 15 minutes at 1000rpm, and the upper beige suspension is sucked out to obtain Platelet Rich Plasma (PRP). Centrifuging the remaining plasma at 3000 rpm for 15min, and collecting supernatant to obtain Platelet Poor Plasma (PPP), and adjusting PRP with PPP to give platelet count of 1×10 ⁸ /mL。

The platelet aggregation rate was measured by turbidimetry at 37 ℃. 260. Mu.L of PRP was placed in a turbidimetric tube, followed by addition of 10. Mu.L of each of the compounds to be tested, incubation at 37℃for 5min, followed by sequential addition of 30. Mu.L of inducer, ADP (Sigma, st.Louis, MO, USA) at a final concentration of 10. Mu.M and AA (Sigma, st.Louis, MO, USA) at a final concentration of 1mM. And measuring the maximum aggregation rate of the control tube and the test tube within 5min by adopting a platelet aggregation instrument, and calculating the inhibition rate of the drug on platelet aggregation. The calculation formula is as follows: platelet aggregation Inhibition Ratio (IRPA) = (control group platelet aggregation ratio-experimental group platelet aggregation ratio)/control group platelet aggregation ratio x 100%.

2. Test results

TABLE 1

As shown in Table 1, both compounds I and VI exhibited strong platelet aggregation inhibition activity under AA (1 mM) and ADP (10. Mu.M) induction. Wherein the ketal-type prodrug (compound I) has more remarkable activity and half-Inhibitory Concentration (IC) on ADP-induced platelet aggregation ₅₀ ) Is 0.13.+ -. 0.006mM.

Example 7: in vivo pharmacokinetic and tissue distribution studies

1. Test method

To further evaluate the in vivo metabolic properties of ketal-type prodrugs (compound I), we determined the in vivo Pharmacokinetic (PK) properties and brain tissue distribution of rats of compound I and compound VI. The rat tail vein was injected with I (10 mg/kg) or VI (10 mg/kg) at a single time, and the PK test groups were sampled at 0, 5, 15, 30min and 1, 2, 4, 6, 8, 24h, and the brain tissue distribution test groups were sacrificed at 15min, 1h and 6h, respectively, and brain tissue was removed and detected and quantitatively analyzed by LC-MS/MS.

2. Test results

TABLE 2

As shown in table 2 and fig. 6, compound VI (10 mg/kg) was directly injected intravenously and was extremely rapidly eliminated in rat plasma, and the elimination half-life was about 0.15±0.07h at the 2h time point was essentially undetectable; while intravenous prodrug I (10 mg/kg) was continuously detected at about 8h time points, its elimination half-life was greatly prolonged (t) _1/2 =1.38±0.26 h). Furthermore, the presence of the drug substance VI was also detected in rat plasma after administration of compound I, and the half-life was also prolonged, indicating that I can be slowly converted to VI in vivo. The above results initially suggest that, compared to compound VI, ketal prodrugsA kind of electronic device with a display unit

Donor I had better PK behaviour.

TABLE 3 Table 3

In addition, the results of the plasma and brain tissue distribution experiments in table 3 show that the ketal type prodrug (compound I) has higher relative concentration in the brain, and the brain/blood concentration ratio at each time point is respectively 2.47, 3.47 and 1.90, which indicates that the compound I has better brain selectivity, and suggests that the ketal modification strategy may have a certain potential in the development and application of drugs in ischemic cerebral apoplexy.

Example 8: evaluation of in vivo anti-cerebral ischemia Activity of selectively released ketal-type prodrugs (Compound I)

1. Test method

Further, compound I exhibiting high activity in vitro was evaluated for in vivo anti-acute cerebral ischemia activity. In order to evaluate the in vivo anti-cerebral ischemia activity of the compound I, a transient rat middle cerebral artery embolism (tMCAO) model manufactured by a nylon wire plug method is selected to simulate an acute cerebral ischemia state, and the wire plug is taken out after ischemia for 2 hours for reperfusion molding. Reference literature reports NaNO ₂ Three doses (225, 900 and 3600. Mu.g/kg) were set up as high, medium and low, respectively, and VI was used as a control, and equal volumes of solvent were administered in the sham and model groups. Intravenous administration was performed 4h, 24h, and 48h after ischemia (i.e., once daily administration), and neurological scoring (Longa's method), cerebral infarct volume, and cerebral edema testing was performed 72h after ischemia.

2. Test results

24 hours after compound dosing, we first scored the neurological deficit for each group of animals according to Longa's method. As shown in fig. 7A, the nerve function of rats in the tMCAO model group was significantly impaired. Compared with the model group, remove NaNO ₂ Outside the groups, each administration group can improve the neural behavior function of rats. Compound VI and ketal prodrugs (compoundsI) The activity is stronger, wherein the compound I administration group shows dose dependency, and the high concentration group has the best curative effect.

Subsequently, we assessed the cerebral infarct volume of each group of rats using TTC staining. As shown in fig. 7B, the model group can observe significant cerebral infarction, and each administration group can reduce the cerebral infarction volume of tMCAO rat to some extent. The activity of each dose group of compound I appears to be better than VI and appears to be dose dependent. Wherein the average cerebral infarction volume inhibition rate of the compound I high dose group (I-H, 3.6 mg/kg) was 79.5%.

Finally, we examined the activity of the compounds against cerebral oedema. The results of the cerebral edema test of each group are shown in fig. 7C. We have found ketal prodrugs

The inhibition of cerebral edema in each of the donor compound I dose groups (86.8%, 92.5%, 97.8% for the low, medium and high dose groups, respectively) was significantly greater than that of the drug substance VI (60.4%).

By combining the above test results, we can summarize that ketal prodrugs

The donor compound I not only has better anti-cerebral infarction and anti-cerebral edema activities, but also has obvious improving effect on animal neuro-behavioural scores, and the high-dose group shows the best performance. The activity of the compound is superior to that of the original drug VI, which indicates that the pro-drug strategy can improve the cerebral ischemia activity of the compound, and suggests that the stability of the target compound I is improved and simultaneously the target compound I can be selectively and efficiently released at the ischemia part>

Claims (8)

1. A compound of formula I, or a pharmaceutically acceptable salt thereof:

2. the method for preparing the compound as claimed in claim 1, wherein the synthetic route of the compound I comprises:

3. a method for preparing a compound according to claim 2, comprising:

reacting the compound II with the compound III in the presence of ammonium persulfate to obtain an intermediate IV;

under the action of a free radical initiator azo diisobutyronitrile AIBN, the intermediate IV is brominated by N-bromosuccinimide NBS to obtain an intermediate V;

intermediate V and silver nitrite AgNO ₂ Obtaining a compound VI through reaction;

and (3) carrying out reflux with water by taking anhydrous benzene as a solvent under the catalysis of p-toluenesulfonic acid and triethyl orthoformate by using the compound VI and ethylene glycol to obtain the target compound I.

4. A pharmaceutical composition comprising a therapeutically effective amount of a compound of claim 1 and a pharmaceutically acceptable carrier.

5. The use of a compound according to claim 1 for the preparation of a medicament for the prophylaxis and/or treatment of ischemic cardiovascular and cerebrovascular diseases.

6. The use according to claim 5, wherein the ischemic cardiovascular and cerebrovascular disease is cerebral ischemia, cerebral apoplexy, myocardial ischemia, myocardial infarction, angina pectoris, arrhythmia or coronary heart disease.

7. Use of a compound according to claim 1 for the preparation of a medicament for the prophylaxis and/or treatment of pulmonary hypertension.

8. The use of the pharmaceutical composition according to claim 4 for the preparation of a medicament for the prophylaxis and/or treatment of cerebral ischemia, myocardial ischemia and pulmonary hypertension.

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