WO2023231254A1 - Avanafil phosphate compounds as well as preparation method therefor and use thereof - Google Patents

Abstract

The present invention relates to the technical field of pharmaceutical compounds. Provided are avanafil phosphate compounds, the structural formula thereof being shown as formula I, wherein R in formula I is hydrogen, phenyl, substituted phenyl, alkyl or substituted alkyl. The avanafil phosphate compounds provided by the present invention have good water solubility, long drug action time, and a good slow release effect, thus having wide application prospects in preparation of drugs for treating phosphodiesterase 5-related diseases. The present invention also provides a preparation method for the avanafil phosphate compounds in the above solution, and the preparation method provided by the present invention involves simple steps and easy operation, thus being suitable for large-scale production.

Description

Avanafil phosphate compound and its preparation method and application

This application requires the priority of the Chinese patent application submitted to the China Patent Office on May 30, 2022, with the application number CN202210595665.6 and the invention name "Avanafil phosphate compound and its preparation method and application" , the entire contents of which are incorporated herein by reference.

Technical field

The technical field of pharmaceutical compounds of the present invention relates in particular to an avanafil phosphate compound and its preparation method and application.

Background technique

Phosphodiesterase 5 (PDE5) belongs to a superfamily of enzymes that can catalyze the conversion of the second messenger cGMP into GMP. PDE5 inhibitors are recommended as first-line drugs for the treatment of erectile dysfunction (ED). In addition, PDE5 inhibitors can also be used to treat diseases such as hypertension, coronary heart disease, and prostatic hyperplasia [Chinese Journal of Medicinal Chemistry. 2017.27.400-07]. According to survey statistics, about 15% of men aged 40 to 59 have ED, and 70% of men in their 60s and 70s have ED. Like many other chronic diseases, the incidence of ED is also Increases with age [Am J Med.2021.134.310-16].

Avanafil is a selective PDE5 inhibitor approved by the US FDA in April 2012 for the treatment of ED. Currently, the PDE5 inhibitors on the market include sildenafil, vardenafil, tadenafil, udenafil and mironafil. Clinical research data shows that many ED patients can successfully have sex within 30 minutes of using avanafil, sildenafil, vardenafil, and tadalafil take about 90 minutes to take effect, and tadalafil takes 2 hours [ Advances in Pharmacy.2012.36.135-36]. Therefore, the rapid-acting advantage of avanafil will be more favored by ED patients. It has the same mechanism of action as other PDE5 inhibitors on the market, but it has unique pharmacokinetic and pharmacodynamic properties and is absorbed faster after oral administration. , higher selectivity, fewer side effects, and the rate of withdrawal of this product due to adverse reactions in long-term clinical trials is also lower [The Annals of pharmacotherapy.2013.47.1312-20]. Accumulated data show that avanafil has better pharmacological effects on ED and has a good market response.

However, avanafil has the disadvantages of poor water solubility and short action time. Therefore, it is of great value to develop water-soluble avanafil and avanafil prodrugs to extend the action time of the drug.

Contents of the invention

In view of this, the present invention provides an avanafil phosphate compound and its preparation method and application. The avanafil phosphate compound provided by the invention has good water solubility and long acting time.

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

An avanafil phosphate ester compound or a pharmaceutically acceptable salt thereof, the structural formula of the avanafil phosphate ester compound is as shown in Formula I:

In formula I: R is hydrogen, phenyl, substituted phenyl, benzyl, alkyl or substituted alkyl;

The substituted phenyl group is a mono-substituted or poly-substituted phenyl group at the ortho, meta or para position;

The substituent on the substituted phenyl group is halogen, nitro or alkyl;

The substituent on the substituted alkyl group is halogen or cyano group.

Preferably, when R is an alkyl group or a substituted alkyl group, the number of carbon atoms in the alkyl group or substituted alkyl group is 1 to 18; when the substituent on the substituted alkyl group is halogen, the halogen is fluorine, Chlorine or bromine.

Preferably, the substituted phenyl group is a monosubstituted phenyl group, a disubstituted phenyl group or a trisubstituted phenyl group. When the substituent on the substituted phenyl group is halogen, the halogen is preferably fluorine, chlorine or bromine. When When the substituent on the substituted phenyl group is an alkyl group, the number of carbon atoms of the alkyl group is 1 to 18.

Preferably, R in formula I is any one of the following groups:

H.

Preferably, the avanafil phosphate compound is any one of Formula II to Formula IV:

The present invention also provides a method for preparing avanafil phosphate compounds described in the above scheme, including method one, method two, method three or method four;

The method one includes the following steps:

Avanafil, a base, a solvent and a compound having the structure represented by formula a are mixed to perform a condensation reaction to obtain an avanafil phosphate ester compound having the structure represented by formula I;

In formula a, R is phenyl, substituted phenyl, alkyl or substituted alkyl;

The second method includes the following steps:

Avanafil, a base, a solvent and a compound having a structure represented by formula b are mixed to perform a condensation reaction to obtain an intermediate reaction liquid; the intermediate product in the intermediate reaction liquid has a structure represented by formula c;

The intermediate reaction solution and m-chloroperoxybenzoic acid solution are mixed to perform an oxidation reaction to obtain an avanafil phosphate ester compound having the structure shown in Formula I;

In formula b and formula c: R is benzyl, phenyl, alkyl or substituted alkyl.

The third method includes the following steps:

(CH ₃ O) ₃ PO, POCl ₃ and avanafil are mixed to perform an esterification reaction to obtain an avanafil phosphate ester compound with a structure shown in Formula I in which R is hydrogen;

The fourth method includes the following steps:

The compound having the structure shown in Formula III, BCl ₃ and a solvent are mixed to perform a debenzylation reaction to obtain an avanafil phosphate ester compound having the structure shown in Formula I in which R is hydrogen.

Preferably, the solvents in Method One and Method Two are independently non-polar solvents or polar aprotic solvents.

Preferably, the base in method one and method two is independently an organic base or an inorganic base; the inorganic base includes an alkali metal carbonate or an alkali metal phosphate; the organic base includes pyridine, 4-dimethylamino One or more of pyridine, triethylamine, trimethylamine and tetrazole.

Preferably, in the method one, the molar ratio of avanafil and alkali is 1:(1.1~1.3), and the molar ratio of avanafil and the compound having the structure shown in formula a is 1:(1.1~1.3 ).

Preferably, in the second method, the molar ratio of avanafil and alkali is 1:(1.1~1.3), and the molar ratio of avanafil and the compound having the structure shown in formula b is 1:(1.1~1.3 ).

The base in method one and method two is independently an organic base or an inorganic base.

Preferably, the temperature of the condensation reaction in the first method is room temperature, and the reaction time is 12 to 24 hours; the temperature of the condensation reaction in the second method is room temperature, and the reaction time is 12 to 24 hours; the temperature of the oxidation reaction in the second method is preferably At room temperature, the time is 4 to 12 hours.

Preferably, in the second method, the mass ratio of m-chloroperbenzoic acid and avanafil is (0.7-0.8):1.

Preferably, the temperature of the esterification reaction in the third method is 0°C to 25°C, and the reaction time is 1h to 8h; the temperature of the debenzylation reaction in the fourth method is room temperature, and the reaction time is 12 to 48h.

The present invention also provides the use of the avanafil phosphate compound or its pharmaceutically acceptable salt described in the above scheme in the preparation of drugs for treating phosphodiesterase 5-related diseases.

Preferably, the phosphodiesterase 5-related diseases include erectile dysfunction-related diseases, hypertension, coronary heart disease or prostatic hyperplasia.

Preferably, during the application, avanafil phosphate compound or its pharmaceutically acceptable salt is used alone or mixed with pharmaceutically acceptable excipients.

Preferably, the dosage form of the drug for treating phosphodiesterase 5-related diseases is tablets, capsules, granules or syrups.

The present invention also provides the use of the avanafil phosphate compound or its pharmaceutically acceptable salt described in the above scheme in the treatment of phosphodiesterase 5-related diseases.

The invention provides an avanafil phosphate compound with a structural formula shown in Formula I. The avanafil phosphate compound provided by the present invention has good water solubility due to its phosphate structure and increased polarity. The sustained-release effect of the phosphate ester allows the drug to have a long action time and is useful in treating phosphodiesterase 5-related diseases. It has broad application prospects in medicines.

The present invention also provides a preparation method for the avanafil phosphate compound described in the above scheme. The preparation method provided by the present invention has simple steps, is easy to operate, and is suitable for large-scale production.

Description of the drawings

Figure 1 is a comparison of the intragastric drug release effects of avanafil and compounds with structures shown in Formula II and Formula III;

Figure 2 is a comparison of the intragastric drug release effects of avanafil and the compound having the structure shown in Formula IV.

Detailed ways

The invention provides an avanafil phosphate compound or a pharmaceutically acceptable salt thereof. The structural formula of the avanafil phosphate compound is as shown in Formula I:

In formula I: R is hydrogen, phenyl, substituted phenyl, alkyl or substituted alkyl;

The substituted phenyl group is a mono-substituted or poly-substituted phenyl group at the ortho, meta or para position;

The substituent on the substituted phenyl group is halogen, nitro or alkyl;

The substituent on the substituted alkyl group is halogen or cyano group.

In the present invention, the substituted phenyl group is preferably a monosubstituted phenyl group, a disubstituted phenyl group or a trisubstituted phenyl group. When the substituent on the substituted phenyl group is halogen, the halogen is preferably fluorine or chlorine. Or bromine, when the substituent on the substituted phenyl group is an alkyl group, the number of carbon atoms of the alkyl group is preferably 1 to 18, more preferably 1 to 5. Specifically, the alkyl group is preferably methyl Or isobutyl.

In the present invention, when R is an alkyl group or a substituted alkyl group, the number of carbon atoms in the alkyl group or substituted alkyl group is preferably 1 to 18, more preferably 1 to 10; The substituent is preferably halogen or cyano, and the halogen is preferably fluorine, chlorine or bromine.

In the present invention, R in formula I is preferably any one of the following groups:

H.

In the present invention, the avanafil phosphate compound is preferably any one of Formula II to Formula IV:

In the present invention, the chemical name of the compound with the structure shown in formula II is: (S)-(1-(4-((3-chloro-4-methoxybenzyl)amino)5-((pyrimidine) -2-methylene)carbamoyl)-2-pyrimidinyl)-2-pyrrolidinyl)methyl phosphate dimethyl ester; the chemical name of the compound with the structure shown in formula III is: (S)- (1-(4-((3-chloro-4-methoxybenzyl)amino)5-((pyrimidin-2-methylene)carbamoyl)-2-pyrimidinyl)-2-pyrrolidinyl) Methyl dibenzyl phosphate; the chemical name of the compound with the structure shown in formula IV is: (S)-(1-(4-((3-chloro-4-methoxybenzyl)amino)5-( (pyrimidin-2-methylene)carbamoyl)-2-pyrimidinyl)-2-pyrrolidinyl)methylphosphonic acid. In specific embodiments of the present invention, the avanafil phosphate compound is most preferably a compound having a structure represented by Formula IV.

The present invention also provides a method for preparing avanafil phosphate compounds described in the above scheme, including method one, method two, method three and method four, wherein method one is used to prepare R is phenyl, substituted phenyl, alkyl Avanafil phosphate ester compounds when R is a benzyl, phenyl, alkyl or substituted alkyl group, method two is used to prepare avanafil phosphate ester compounds when R is a benzyl, phenyl, alkyl or substituted alkyl group, method three and method Four is used to prepare avanafil phosphate ester compounds when R is hydrogen (i.e., avanafil phosphate ester compounds represented by formula IV). Detailed descriptions are given below:

In the present invention, the method one includes the following steps:

Avanafil, a base, a solvent and a compound having the structure shown in formula a are mixed to perform a condensation reaction to obtain an avanafil phosphate ester compound having a structure shown in formula I;

In formula a, R is a phenyl group, a substituted phenyl group, an alkyl group or a substituted alkyl group. The types of the substituted phenyl group and the substituted alkyl group are consistent with the above scheme and will not be described again here.

In the present invention, the synthetic route of method one is shown in the following formula:

In the present invention, the solvent used in the method one is preferably a non-polar solvent or a polar aprotic solvent, and more preferably includes dichloromethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, N , one or more of N-dimethylacetamide and dimethyl sulfoxide; the base is preferably an inorganic base or an organic base, and the inorganic base preferably includes an alkali metal carbonate or an alkali metal phosphate, The alkali metal carbonate preferably includes one or more of potassium carbonate, cesium carbonate and sodium carbonate, the alkali metal phosphate preferably includes one or both of potassium phosphate and sodium phosphate; the organic base Preferably, it includes one or more of pyridine, 4-dimethylaminopyridine, triethylamine, trimethylamine and tetrazole.

In the present invention, in the method one, the molar ratio of avanafil and alkali is preferably 1:(1.1~1.3), more preferably 1:1.2; the avanafil and alkali have the structure shown in formula a The molar ratio of the compound is preferably 1: (1.1~1.3), more preferably 1:1.2; the present invention has no special requirements on the source of the compound having the structure shown in formula a, and the above-mentioned compound on the market is used or the present invention is used. It can be synthesized by methods well known to those skilled in the art. The present invention has no special requirements on the amount of the solvent, as long as it can ensure the smooth progress of the reaction.

In the present invention, the temperature of the condensation reaction in the method one is preferably room temperature, and the reaction time is preferably 12 to 24 hours; the condensation reaction is preferably carried out under nitrogen protection conditions; in specific embodiments of the present invention, it is preferred to first Dissolve avanafil in the solvent, then add a base, and then cool it in an ice-water bath for 15 minutes under nitrogen protection. Use a syringe to add a compound with the structure shown in formula a to the reaction solution, and then naturally warm it to room temperature for reaction. The present invention preferably uses TLC to monitor the reaction, and stops the reaction after the raw material reaction is complete; the reagent used in the TLC monitoring is a mixed solvent of methanol and dichloromethane, and the volume fraction of methanol in the mixed solvent is preferably 5%, recorded as 5 %MeOH/DCM.

After the reaction is completed, the present invention preferably evaporates the solvent in the obtained reaction liquid to dryness to obtain a crude product, which is then purified by silica gel column chromatography to obtain avanafil phosphates having the structure shown in Formula I. Compound; in the present invention, the elution reagent used for the silica gel column chromatography purification is a mixed solvent of methanol and dichloromethane, and the volume ratio of methanol and dichloromethane in the mixed solvent is preferably 1:(20-30 ).

In the present invention, the second method includes the following steps:

Avanafil, a base, a solvent and a compound having a structure represented by formula b are mixed to perform a condensation reaction to obtain an intermediate reaction liquid; the intermediate product in the intermediate reaction liquid has a structure represented by formula c;

The intermediate reaction solution and the m-CPBA solution are mixed to perform an oxidation reaction to obtain an avanafil phosphate compound having the structure shown in Formula I;

In formula b and formula c: R is benzyl, phenyl, alkyl or substituted alkyl.

In the present invention, the synthetic route of method two is as follows:

In the present invention, avanafil, a base, a solvent and a compound having the structure shown in formula b are first mixed to perform a condensation reaction to obtain an intermediate reaction liquid. In the present invention, the solvent used in the second method is preferably a non-polar solvent or a polar aprotic solvent, and more preferably includes dichloromethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, N , one or more of N-dimethylacetamide and dimethyl sulfoxide; the base is preferably an inorganic base or an organic base, and the inorganic base preferably includes an alkali metal carbonate or an alkali metal phosphate, The alkali metal carbonate preferably includes one or more of potassium carbonate, cesium carbonate and sodium carbonate, the alkali metal phosphate preferably includes one or both of potassium phosphate and sodium phosphate; the organic base Preferably, it includes one or more of pyridine, 4-dimethylaminopyridine, triethylamine, trimethylamine and tetrazole.

In the present invention, in the method two, the molar ratio of avanafil and alkali is preferably 1:(1.1~1.3), more preferably 1:1.2; the avanafil and alkali have the structure shown in formula b The molar ratio of the compound is preferably 1: (1.1 ~ 1.3), more preferably 1:1.2; the present invention has no special requirements on the source of the compound having the structure shown in formula b. The above-mentioned compound on the market is used or the present invention is used. It can be synthesized by methods well known to those skilled in the art. The present invention has no special requirements on the amount of the solvent, as long as it can ensure the smooth progress of the reaction.

In the present invention, the temperature of the condensation reaction in the second method is preferably room temperature, the reaction time is preferably 12 to 24 hours, and the condensation reaction is preferably carried out under nitrogen protection conditions. In specific embodiments of the present invention, it is preferred to first dissolve avanafil in a solvent, then add a base, and then stir for 5 minutes under nitrogen protection conditions. Use a syringe to add a compound with the structure shown in formula b into the reaction solution and The reaction was carried out under stirring conditions. After the reaction is completed, there is no need to perform any processing and the reaction can be carried out directly to the next step.

After obtaining the intermediate reaction liquid, the present invention mixes the intermediate reaction liquid and m-CPBA (meta-chloroperoxybenzoic acid) solution to perform an oxidation reaction to obtain avanafil phosphate ester compounds having the structure shown in Formula I. In the present invention, the solvent used in the m-CPBA solution is preferably consistent with the solvent used in the condensation reaction step, which will not be described in detail here; the concentration of the m-CPBA solution is preferably 0.143g/mL; the m- The mass ratio of CPBA and avanafil is preferably (0.7-0.8):1, more preferably 0.715:1.

In the present invention, the temperature of the oxidation reaction is preferably room temperature, and the reaction time is preferably 4 to 12 hours; in specific embodiments of the present invention, it is preferred to first transfer the intermediate reaction solution to a -78°C cold trap, cool and stir for 15 minutes, Then use a constant pressure dropping funnel to add the m-CPBA solution, and after the addition is completed, the temperature is naturally raised to room temperature to perform the oxidation reaction; the present invention preferably uses TLC to monitor the reaction, and stops the reaction after the raw material reaction is complete; the reagent used in the TLC monitoring is methanol and dichloromethane, the volume fraction of methanol in the mixed solvent is preferably 5%, recorded as 5% MeOH/DCM.

After the oxidation reaction is completed, the present invention preferably mixes the obtained product liquid and water and then separates the layers. The aqueous layer is extracted with an organic solvent. The obtained organic layer is washed with saturated sodium chloride, dried with anhydrous sodium sulfate and evaporated to dryness in order to obtain a crude product. product, and the obtained crude product is purified by silica gel column chromatography to obtain avanafil phosphate ester compounds having the structure shown in Formula I. In the present invention, the organic solvent for extraction is preferably dichloromethane, and the number of extractions is preferably 2 times; the elution reagent used for the silica gel column chromatography purification is a mixed solvent of methanol and dichloromethane, so The volume ratio of methanol and methylene chloride in the mixed solvent is preferably 1: (20-30).

In the present invention, the third method includes the following steps:

(CH ₃ O) ₃ PO, POCl ₃ and avanafil are mixed to perform an esterification reaction to obtain an avanafil phosphate ester compound having a structure represented by formula IV.

In the present invention, the synthetic route of method three is shown in the following formula:

In the present invention, the dosage ratio of (CH ₃ O) ₃ PO, POCl ₃ and avanafil is preferably 6 mL: 6 mL: 1 mol; the temperature of the esterification reaction is preferably 0 to 25°C, and the reaction time is preferably It is 1 to 8 hours; in the specific embodiment of the present invention, preferably at 5°C, avanafil is added to the mixture of (CH ₃ O) ₃ PO and POCl ₃ , and then stirred rapidly until the reaction is complete. After the reaction is completed, the present invention preferably quenches the reaction with ice water, adjusts the pH value of the obtained aqueous solution to 4 to 6 with NaOH, and then uses a C ₁₈ column to purify the avanafil phosphate ester compound; the C ₁₈ column The eluent used for purification is preferably a mixed solvent of methanol and water. The volume ratio of methanol and water in the mixed solvent is preferably 1: (1-10). In specific embodiments of the present invention, the C18 column purification The elution method used is preferably gradient elution, preferably in a volume ratio of methanol and water of 1:10, 2:8:3:7, 4:6:5:5, and 6:4. Collect the components eluted when the volume ratio is 6:4.

In the present invention, the fourth method includes the following steps:

The compound having the structure represented by Formula III, BCl ₃ and a solvent are mixed to perform a debenzylation reaction to obtain an avanafil phosphate ester compound having the structure represented by Formula IV.

In the present invention, the synthetic route of method four is as follows:

In the present invention, the solvent used in the method four is preferably a non-polar solvent or a polar aprotic solvent, and more preferably includes dichloromethane, 1,2-dichloroethane, dioxane, tetrahydrofuran, N, One or more of N-dimethylacetamide and dimethyl sulfoxide; the molar ratio of the compound having the structure shown in formula II and BCl ₃ is preferably 1:12.5; the debenzylation reaction The temperature is preferably room temperature, and the reaction time is preferably 12 to 48 hours. In specific embodiments of the present invention, it is preferred to first dissolve the compound having the structure shown in Formula II in a solvent, then add BCl ₃ solution at 0°C, and then warm to room temperature to carry out the reaction. LC-MS monitors until the reaction is completed. ; The concentration of the BCl ₃ solution is preferably 1 mol/L, and the solvent used in the BCl ₃ solution is preferably consistent with the solvent used in the debenzylation reaction, which will not be described again here.

After the debenzylation reaction is completed, the present invention preferably adds a saturated sodium bicarbonate solution to the obtained product liquid for neutralization, and then freeze-dries the obtained neutralized liquid to obtain a crude product, which is purified using a C ₁₈ column to obtain Avanafil phosphate compound; the eluent used for the C ₁₈ column purification is preferably a mixed solvent of methanol and water, and the volume ratio of methanol and water in the mixed solvent is preferably 1: (1-10).

The present invention also provides the use of the avanafil phosphate compound or its pharmaceutically acceptable salt described in the above scheme in the preparation of drugs for treating phosphodiesterase 5-related diseases; in the present invention, the phosphoric acid Diesterase 5-related diseases preferably include erectile dysfunction-related diseases, hypertension, coronary heart disease or prostatic hyperplasia; when used, avanafil phosphate compounds or pharmaceutically acceptable salts thereof are preferably used alone or together with Medicinal auxiliary materials are mixed and used; the present invention has no special requirements for the specific types of the auxiliary materials, and auxiliary materials well known to those skilled in the art can be used, such as excipients, diluents, etc., in specific embodiments of the present invention, Preferably, the above-mentioned avanafil phosphate ester compound or its pharmaceutically acceptable salt is prepared into tablets, capsules, granules or syrups for oral administration using excipients.

The technical solutions in the present invention will be described clearly and completely below with reference to the embodiments of the present invention, but they should not be understood as limiting the protection scope of the present invention.

In the following examples, ¹ H-NMR was recorded with a JEOL JNM-ECZS 400 nuclear magnetic resonance instrument, and the chemical shift was expressed in δ (ppm); the silica gel used for separation and purification was 200-300 mesh (not specified), and the eluent ratio was uniform. It is a volume ratio. Unless otherwise specified, the reagents used are of commercially available analytical grade.

Example 1

(S)-(1-(4-((3-chloro-4-methoxybenzyl)amino)5-((pyrimidin-2-methylene)carbamoyl)-2-pyrimidinyl)-2- Preparation of dimethylpyrrolidinyl)methylphosphate (formula II), the reaction formula is as follows:

Dissolve avanafil (2.0g, 4.13mmol) in DCM (50mL), add Py (400mg, 4.96mmol), protect with nitrogen, cool in an ice-water bath for 15 minutes, add O,O-dimethylphosphoryl chloride (720mg) with a syringe ,4.96mmol), naturally warmed to room temperature, and stirred overnight. Monitor the reaction with TLC (5% MeOH/DCM). Stop the reaction after the raw material reaction is complete, directly evaporate the solvent to dryness, and elute with column chromatography with 4-5% MeOH/DCM to obtain 1.64g of yellow oil with a yield of 67.2%.

¹ H NMR(400MHz,Chloroform-d)δ9.02(t,J＝5.9Hz,1H),8.69(d,J＝4.9Hz,2H),8.39(d,J＝11.5Hz,1H),7.44– 7.28(m,2H),7.23–7.12(m,2H),6.83(d,J＝7.8Hz,1H),4.75(d,J＝4.5Hz,2H),4.66–4.45(m,2H),4.38 –4.22(m,2H),3.83(s,3H),3.76–3.44(m,9H),2.16–1.87(m,4H).HPLC-MS(ESI ⁺ ):[M+H] ⁺ :593.0

Example 2

(S)-(1-(4-((3-chloro-4-methoxybenzyl)amino)5-((pyrimidin-2-methylene)carbamoyl)-2-pyrimidinyl)-2- Preparation of dibenzyl pyrrolidinyl)methyl phosphate (formula III), the reaction formula is as follows:

Dissolve avanafil (2.0g, 4.13mmol) in DCM (50mL), add tetrazole (350mg, 4.96mmol), protect with nitrogen, stir at room temperature for 5 minutes, add diphenyl N,N'-diiso with a syringe Propylphosphoramidite (1.72g, 4.96mmol), stir overnight. The reaction solution was transferred to a -78°C cold trap, cooled and stirred for 15 minutes. A dichloromethane solution of m-CPBA (1.43g, 10mL DCM) was added to the constant pressure dropping funnel. m-CPBA was added dropwise to the reaction solution. After the dropwise addition was completed, the temperature was raised naturally. to room temperature. The reaction was monitored by TLC (5% MeOH/DCM), and the reaction was stopped after the reaction was complete for 6 hours at room temperature. Add 100 mL of water, separate the layers, extract the water layer with DCM 50 mL Product 1.7g, yield 55.4%.

¹ H NMR (400MHz, Chloroform-d) δ9.28–9.11(m,1H),8.69(d,J＝5.0Hz,2H),8.59(s,1H),7.95(t,J＝1.9Hz,1H ),7.87(dd,J＝7.7,1.5Hz,1H),7.84–7.74(m,1H),7.45–7.39(m,1H),7.31(d,J＝11.4Hz,2H),7.25(d, J＝7.7Hz,3H),7.19(t,J＝5.0Hz,2H),7.07(td,J＝9.1,3.5Hz,1H),6.76(d,J＝8.8Hz,1H),5.25(s, 1H),4.98(td,J＝9.0,3.2Hz,4H),4.79(d,J＝4.9Hz,2H),4.52(p,J＝7.4,6.6Hz,1H),4.32–4.18(m,2H ),4.07–3.89(m,1H),3.79(d,J＝13.2Hz,3H),3.72–3.41(m,2H),2.03–1.82(m,4H).HPLC-MS(ESI ⁺ ):[ M+H] ⁺ :745.1

Example 3

(S)-(1-(4-((3-chloro-4-methoxybenzyl)amino)5-((pyrimidin-2-methylene)carbamoyl)-2-pyrimidinyl)-2- Preparation of pyrrolidinyl)methylphosphonate (Compound III). Preparation is carried out using Route 1 and Route 2 respectively. The reaction formula of Route 1 is as follows:

To a solution of (CH ₃ O) ₃ PO (6 mL) and POCl ₃ (6 mL, 40 mmol) at 5°C, avanafil (1.0 g, 2.0 mmol) was added and stirred rapidly. After the reaction is complete, the reaction is quenched with ice water. The pH of the obtained aqueous solution is adjusted to 4-6 with NaOH (pH test paper is yellow), and directly loaded onto the C ₁₈ column. Elute with 400 mL of water and 200 mL of methanol to obtain the product. The methanol is rotary evaporated. to 50 mL, and allowed to stand for crystallization to obtain 1.4 g of product, with a yield of 62%.

The reaction equation of route 2 is as follows:

Compound II (1.0 g, 1.3 mmol) was dissolved in DCM (20 mL), 1 mol/L BCl ₃ solution (16.25 mL) was added at 0°C, and stirred at room temperature for 2 days. Monitor the reaction with LC-MS. After the reaction is complete, add saturated sodium bicarbonate to adjust the pH to 7. The reaction solution is freeze-dried and purified using a C ₁₈ column MeOH: H ₂ O = 1:10 to 3:2 gradient elution to obtain a white solid product. 300mg, yield 40.8%.

¹ H NMR (400MHz, DMSO-d ₆ ) δ9.14 (dt, J＝11.6, 6.0Hz, 1H), 8.82 (dt, J＝11.8, 5.8Hz, 1H), 8.75 (d, J＝4.9Hz, 2H),8.54(d,J＝4.2Hz,1H),7.37(dd,J＝8.6,3.7Hz,2H),7.34–7.23(m,1H),7.07(t,J＝7.5Hz,1H), 4.57(d,J＝5.9Hz,3H),4.29–3.89(m,5H),3.80(s,3H),3.65–3.37(m,3H),2.11–1.71(m,4H).HPLC-MS( ESI+):[M+H] ⁺ :564.1.

Test Example 1 Water Solubility Test

1. Equipment of standard curve

Weigh 500 mg of the sample and grind it in a mortar for 5 minutes, weigh 24.57 mg in a 50 mL volumetric flask, dilute it with methanol to the mark, and dissolve it with ultrasonic for 5 minutes. The solubility of the obtained mother liquor was 0.4914 mg/mL. The mother liquor was diluted according to the ratio in Table 1 to obtain a linear solution.

Table 1 Dilution ratio of mother liquor

2. The standard curve is measured using UV instrument

UV model: SHIMADZU UV-2550 UV-visible spectrophotometer

Detection wavelength: 260nm

The standard curve obtained from the test is: y=0.0248x+0.0185, R ² =0.9984, r=0.9992, where y is the solubility and x is the absorbance;

3. Precisely weigh the sample to be tested (about 20mg), add pure water to adjust the volume to 2mL, and vortex for 20 seconds. After the sample is filtered with a 0.22μm filter membrane, the filtrate is diluted 100 times with water to be tested (pipette 100μl to a 10 mL volumetric flask, constant volume), test the absorbance at a wavelength of 260 nm, and substitute the test results into the standard curve to calculate the solubility.

The test results are as follows:

Compound of formula II: absorbance: 0.476, solubility: 18.44 μg/mL, multiplied by the dilution factor of 100, solubility: 1.872 mg/mL. Compound of formula III: absorbance: 0.481, solubility: 18.65 μg/mL, multiplied by the dilution factor of 100, solubility: 1.840 mg/mL. Compound of formula IV: absorbance: 0.869, solubility: 34.29 μg/mL, multiplied by the dilution factor of 100, solubility: 3.392 mg/mL.

Test Example 2 Biological Activity Test

The activity of the compounds of the invention was evaluated by testing the rate of release of avanafil in rats.

Experimental principles and methods: Based on ultra-high performance liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS), the plasma concentrations of avanafil and avanafil phosphate derivative compounds were compared in rats after intraperitoneal administration.

experimental method:

(1) Liquid sample preparation: After reviewing the pharmacokinetics literature of avanafil, it was found that it is difficult to detect the prototype drug of avanafil after 6 hours, so this experiment chose to detect blood samples within 1 hour of intraperitoneal administration. Using the liquid-liquid extraction method, place 300 μL of serum and 300 μL of ethyl acetate into a clean EP tube, vortex to mix, and then aspirate the supernatant, repeat three times, and combine the supernatants. After the supernatant was vacuum dried, the residue was redissolved by adding 200 μL of 75% acetonitrile, centrifuged at low temperature and high speed (18000g, 4 degrees Celsius) for 20 min, and 150 μL was pipetted and placed in a sampling bottle for analysis.

(2) Liquid phase analysis conditions:

Chromatographic conditions: The chromatographic column is AgilentZORBAX Eclipse Plus C ₁₈ column (2.1×100mm, 1.8μm), mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is acetonitrile, gradient elution is performed as specified in Table 1, and the flow rate is 0.4 mL/min, column temperature is 25°C, injection volume: 2 μL.

Table 1 Gradient elution program (volume fraction)

(3) Mass spectrometry conditions: Apply ESI ⁺ positive mode for detection, gas temperature (Gas temp.) is 325°C, drying gas (Drying Gas) is 8L/min, nebulizer (Nebulizer) is 35psi, sheath gas temperature (Sheath Gas temp. .) is 350℃, the sheath gas flow rate (Aux Gas Flow) is 11L/min, the capillary voltage (VCap) is 4000V, the fragmentation voltage (Fragment) is 150V, the skimmer (Skimmer) is 65V, and Oct 1 RF Vpp is 750V . Use ESI-L Low Concentration tuning Mix (G1969-8500) to correct the accurate mass. The first-level mass spectrometry scanning range: m/z 50 ~ 1100; the second-level mass spectrometry selects the top three based on the first-level scan to perform induced collision dissociation (CID) to obtain the second-level mass spectrometry data.

Experimental results:

Chromatography and mass spectrometry optimization: Avanafil is a heterocyclic compound containing nitrogen heteroatoms (the structural formula is shown in Formula V). Its molecular formula is C ₂₃ H ₂₇ ClN ₇ O ₃ , and its accurate molecular weight is 483.1858 Da. It has a chromatographic peak in the ESI ⁺ state. The response is better than ESI ^- state chromatographic peaks. Therefore, we chose to monitor the chromatographic peak of [M+H] ⁺ = 484.1858 of avanafil. The peak appeared at 7.88 minutes in the chromatogram. There was no other impurity interference near this retention time, indicating that the chromatographic specificity was good.

The comparative results of the drug release effects of avanafil phosphate esters and avanafil administered by intragastric administration are shown in Figures 1 and 2. Figure 1 shows the intragastric administration of avanafil and compounds with structures shown in Formula II and Formula III. Comparison of drug release effects. Figure 2 shows the comparison of intragastric drug release effects of avanafil and the compound with the structure shown in formula IV. In Figures 1 to 2, AV represents the original drug of avanafil, and II, III, and IV represent Compounds with structures represented by formulas II, III, and IV are subsequently represented as compound (II), compound (III), and compound (IV).

According to Figure 1, it can be seen that the blood concentration of avanafil begins to decrease after 1 hour of avanafil compared to 0.5 hours of avanafil, indicating that avanafil enters the excretion phase. Compound (II) 1h compared to compound (II) 0.5h, avanafil blood concentration began to increase, indicating that avanafil is in the absorption phase. Therefore, it shows that compound (II) may have a certain sustained-release effect; the blood concentration of avanafil begins to decrease at 1 h of compound (III) compared with 0.5 h of compound (III), indicating that compound (III) enters the excretion phase and has no sustained-release effect. Comparing with Compound (IV) 0.5h, the blood concentration of avanafil began to rise at 1h of compound (IV), indicating that avanafil was in the absorption phase, and the blood concentration at 1h reached 80% of avanafil, thus indicating derivatization Compound (IV) has good sustained release effect.

The above are only the preferred embodiments of the present invention. It should be pointed out that those of ordinary skill in the art can also make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications can also be made. should be regarded as the protection scope of the present invention.

Claims (20)

1. An avanafil phosphate ester compound or a pharmaceutically acceptable salt thereof, characterized in that the structural formula of the avanafil phosphate ester compound is as shown in Formula I:

   

   In formula I: R is hydrogen, phenyl, substituted phenyl, benzyl, alkyl or substituted alkyl;

   The substituted phenyl group is a mono-substituted or poly-substituted phenyl group at the ortho, meta or para position;

   The substituent on the substituted phenyl group is halogen, nitro or alkyl;

   The substituent on the substituted alkyl group is halogen or cyano group.
2. The avanafil phosphate compound or a pharmaceutically acceptable salt thereof according to claim 1, wherein when R is an alkyl group or a substituted alkyl group, the carbon atom of the alkyl group or substituted alkyl group The number is 1 to 18; when the substituent on the substituted alkyl group is halogen, the halogen is fluorine, chlorine or bromine.
3. The avanafil phosphate compound or a pharmaceutically acceptable salt thereof according to claim 1, wherein the substituted phenyl group is a monosubstituted phenyl group, a disubstituted phenyl group or a trisubstituted phenyl group. When the substituent on the substituted phenyl group is halogen, the halogen is fluorine, chlorine or bromine; when the substituent on the substituted phenyl group is an alkyl group, the number of carbon atoms of the alkyl group is 1 to 18 .
4. The avanafil phosphate compound or a pharmaceutically acceptable salt thereof according to claim 1, wherein R in the formula I is any one of the following groups:

   H.

   

   
5. The avanafil phosphate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 4, characterized in that the avanafil phosphate compound is one of the formulas II to IV. Any of:

   
6. The preparation method of avanafil phosphate compound according to any one of claims 1 to 5, characterized in that it includes method one, method two, method three or method four;

   The method one includes the following steps:

   Avanafil, a base, a solvent and a compound having the structure represented by formula a are mixed to perform a condensation reaction to obtain an avanafil phosphate ester compound having the structure represented by formula I;

   

   In formula a, R is phenyl, substituted phenyl, alkyl or substituted alkyl;

   The second method includes the following steps:

   Avanafil, a base, a solvent and a compound having a structure represented by formula b are mixed to perform a condensation reaction to obtain an intermediate reaction liquid; the intermediate product in the intermediate reaction liquid has a structure represented by formula c;

   The intermediate reaction solution and m-chloroperoxybenzoic acid solution are mixed to perform an oxidation reaction to obtain an avanafil phosphate ester compound having the structure shown in Formula I;

   

   In formula b and formula c: R is benzyl, phenyl, alkyl or substituted alkyl.

   The third method includes the following steps:

   (CH ₃ O) ₃ PO, POCl ₃ and avanafil are mixed to perform an esterification reaction to obtain an avanafil phosphate ester compound with a structure shown in Formula I in which R is hydrogen;

   The fourth method includes the following steps:

   Mix a compound with the structure shown in Formula III, BCl ₃ and a solvent to perform a debenzylation reaction to obtain an avanafil phosphate ester compound with the structure shown in Formula I in which R is hydrogen;

   
7. The preparation method according to claim 6, characterized in that the solvents in the first method and the second method are independently non-polar solvents or polar aprotic solvents.
8. The preparation method according to claim 6, characterized in that the base in method one and method two is independently an organic base or an inorganic base; the inorganic base includes an alkali metal carbonate or an alkali metal phosphate; The organic base includes one or more of pyridine, 4-dimethylaminopyridine, triethylamine, trimethylamine and tetrazole.
9. The preparation method according to claim 6 or 8, characterized in that, in the method one, the molar ratio of avanafil and alkali is 1: (1.1-1.3), and avanafil and alkali have the formula a The molar ratio of the compounds in the structure is 1:(1.1～1.3).
10. The preparation method according to claim 6 or 8, characterized in that, in the second method, the molar ratio of avanafil and alkali is 1: (1.1~1.3), and avanafil and avanafil have the formula b The molar ratio of the compounds in the structure is 1:(1.1～1.3).
11. The preparation method according to claim 6, characterized in that in the method one, the temperature of the condensation reaction is room temperature, and the reaction time is 12 to 24 hours.
12. The preparation method according to claim 6, wherein the temperature of the condensation reaction in the second method is room temperature and the reaction time is 12 to 24 hours; the temperature of the oxidation reaction in the second method is room temperature and the reaction time is 4 to 12 hours. .
13. The preparation method according to claim 6 or 12, characterized in that, in the second method, the mass ratio of m-chloroperoxybenzoic acid and avanafil is (0.7-0.8):1.
14. The preparation method according to claim 6, characterized in that in the third method, the temperature of the esterification reaction is 0°C to 25°C, and the reaction time is 1h to 8h.
15. The preparation method according to claim 6, characterized in that in the fourth method, the temperature of the debenzylation reaction is room temperature, and the reaction time is 12 to 48 hours.
16. Application of the avanafil phosphate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 5 in the preparation of a drug for treating phosphodiesterase 5-related diseases.
17. The application according to claim 15, wherein the phosphodiesterase 5-related diseases include erectile dysfunction-related diseases, hypertension, coronary heart disease or prostatic hyperplasia.
18. The application according to claim 15, characterized in that during the application, the avanafil phosphate compound or its pharmaceutically acceptable salt is used alone or mixed with pharmaceutically acceptable excipients.
19. The application according to claim 16, wherein the dosage form of the drug for treating phosphodiesterase 5-related diseases is tablets, capsules, granules or syrups.
20. Use of the avanafil phosphate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 5 in the treatment of phosphodiesterase 5-related diseases.

Images