A method for preparing a lipexoridine nitrosamine impurity

Abstract

The application relates to the technical field of chemical synthesis, in particular to a preparation method of a lirupilin nitrosoamine impurity, which comprises the following specific reaction steps: S1. lirupilin is added into a solvent, stirring and reaction are carried out; then a nitrosating reagent is added, and stirring and reaction are continuously carried out; S2. after the reaction is completed, a solvent is added into the reaction solution, and extraction is carried out, so as to form an aqueous phase and an organic phase, the aqueous phase is removed, the organic phase is washed with saturated brine, and then the washed organic phase is dried under reduced pressure, so as to obtain a lirupilin nitrosoamine impurity crude product. The preparation method of the lirupilin nitrosoamine impurity has high product yield, and the product can be used as a control sample of the lirupilin nitrosoamine impurity.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, specifically to a method for preparing nitrosamine impurities such as ribavirin. Background Technology

[0002] Rilpivirine, chemically known as (E)-4-((4-((4-(2-cyanovinyl)-2,6-dimethylphenyl)amino)pyrimidin-2-yl)amino)benzonitrile, is a non-nucleoside reverse transcriptase inhibitor. Clinically, this drug is often used in combination with other antiretroviral drugs to treat human immunodeficiency virus (HIV) infections.

[0003] In recent years, the control of nitrosamine impurities in pharmaceuticals has become a key focus of global drug regulation. Nitrosamine compounds pose a potential genotoxic risk and can be harmful to humans even at extremely low concentrations. Therefore, international drug regulatory agencies (such as ICH, FDA, and EMA) require pharmaceutical companies to conduct rigorous risk assessments and content controls on nitrosamine impurities in their drugs.

[0004] From a chemical structure perspective, the ripivirine molecule contains a secondary amine group, which can react with nitrosating agents under specific conditions to form nitrosamine impurities. Because this impurity originates directly from the structural characteristics of the active pharmaceutical ingredient itself, it is a typical "drug-substance-related nitrosamine impurity." Controlling this type of impurity is challenging because its formation is closely related to the chemical properties of the drug molecule itself.

[0005] Currently, to accurately detect the content of nitrosamine impurities in rilpivirine raw materials or formulations, it is essential to obtain high-purity, structurally confirmed nitrosamine impurity reference standards. However, existing literature and patents report few methods for preparing specific nitrosamine impurities in rilpivirine, lacking systematic synthetic routes and characterization data. Furthermore, whether these nitrosamine impurities carry genotoxicity requires verification through standardized toxicological testing using reference standards. Summary of the Invention

[0006] To address the problems mentioned above in the background art, the present invention provides a method for preparing nitrosamine impurities of rilpivirine, which has a high yield and can be used as a reference standard for nitrosamine impurities of rilpivirine.

[0007] The solution adopted by this invention to solve its technical problem is: a method for preparing nitrosamine impurities from ripivirine, the reaction route of which is as follows: ; The specific reaction steps are as follows: S1. Add rilpivirine to the solvent, stir and react; then add the nitrosating agent, and continue stirring and reacting; S2. After the reaction is complete, solvent is added to the reaction solution and extraction is performed to form an aqueous phase and an organic phase. The aqueous phase is removed, and the organic phase is washed with saturated brine. The washed organic phase is then dried under reduced pressure to obtain crude nitrosamine impurity ribavirin.

[0008] Furthermore, the solvent in step S1 is one of dichloromethane, dimethyl sulfoxide, and acetonitrile.

[0009] Furthermore, the solvent in step S2 can be an organic solvent, such as ethyl acetate, dichloromethane, or toluene.

[0010] Furthermore, in step S1, after adding lipavirin to the solvent, an acid is added, which can be one or more of acetic acid, phosphoric acid, and hydrochloric acid.

[0011] Furthermore, the nitrosating agent is one of sodium nitrite, tert-butyl nitrite, isoamyl nitrite, or N-nitroso-p-toluenesulfonamide.

[0012] Furthermore, the solvent in step S1 is a mixture of dichloromethane and tetrahydrofuran.

[0013] In summary, the beneficial effects of this invention are as follows: This application utilizes the secondary amine group in lipivorelin for nitrosation, simulating the structure of nitrosamine impurities formed during drug production or storage, providing a reliable material basis for subsequent development of genotoxicity assessment and content detection methods.

[0014] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0015] Figure 1 The 1H NMR spectrum of the nitrosamine impurity of ripivirine; Figure 2 The liquid chromatogram of nitrosamine impurity in ribavirin; Figure 3 This is the mass spectrum of the nitrosamine impurity in ribavirin. Detailed Implementation

[0016] To make the content of this invention easier to understand, the invention will be further described below with reference to specific embodiments and accompanying drawings.

[0017] Example 1

[0018] Add 5 g of ripavirin to 50 mL of acetonitrile, then add 40 mL of 3 mol / L hydrochloric acid and 2 g of sodium nitrite in sequence, stir until completely dissolved, and then continue to stir the reaction at room temperature for 24 hours.

[0019] After the reaction was complete, 100 mL of water was added to the reaction solution, and the mixture was extracted with 150 mL of ethyl acetate. The aqueous phase was discarded after separation, and the organic phase was washed with saturated brine, concentrated under reduced pressure, and dried to obtain the crude product. The crude product was purified by column chromatography: impurities were first removed by elution with petroleum ether-ethyl acetate (10:1, v / v), and then the target product was collected by elution with petroleum ether-ethyl acetate (5:1, v / v), yielding 2.3 g of nitrosamine impurity nitrilolide, with a yield of 42.6%.

[0020] Example 2

[0021] Add 10 g of ripavirin to 100 mL of dimethyl sulfoxide, then add 80 mL of 3 mol / L hydrochloric acid and 4 g of sodium nitrite in sequence, stir until completely dissolved, and then continue to stir the reaction at room temperature for 24 hours.

[0022] After the reaction was complete, 100 mL of water was added to the reaction solution, and the mixture was extracted with 150 mL of ethyl acetate. The aqueous phase was discarded after separation, and the organic phase was washed with saturated brine, concentrated under reduced pressure, and dried to obtain the crude product. The crude product was purified by column chromatography: impurities were first removed by elution with petroleum ether-ethyl acetate (10:1, v / v), and then the target product was collected by elution with petroleum ether-ethyl acetate (5:1, v / v), yielding 6 g of nitrosamine impurity ripivirine, with a yield of 55.6%.

[0023] Example 3

[0024] Add 10 g of ripavirin to 100 mL of dichloromethane, then add 10 mL of acetic acid and 6 g of sodium nitrite in sequence, stir until completely dissolved, and then continue stirring at room temperature for 24 hours.

[0025] After the reaction was completed, the reaction solution was concentrated and dried under reduced pressure to obtain the crude product. The crude product was purified by column chromatography: first, impurities were removed by elution with petroleum ether-ethyl acetate (10:1, v / v), and then the target product was collected by elution with petroleum ether-ethyl acetate (5:1, v / v). The product was concentrated and dried under reduced pressure to obtain 7 g of nitrosamine impurity ripivirine, with a yield of 64.9%.

[0026] Example 4

[0027] 5.0 g (13.64 mmol) of ripivirine was dissolved in a mixed solvent of anhydrous dichloromethane (DCM) and tetrahydrofuran (THF) (DCM:THF = 9:1, v / v) to prepare a 0.02 mol / L solution (total volume approximately 682 mL). Under nitrogen protection, N-nitroso-p-toluenesulfonamide (N-NTS, 3.28 g, 16.37 mmol, 1.2 equivalents) was added to the above solution, and the mixture was stirred at 25 °C for 4 hours (TLC monitoring showed the starting material spot disappeared).

[0028] After the reaction was complete, 100 mL of saturated sodium bicarbonate aqueous solution was added to quench the reaction. The mixture was stirred for 10 minutes, and the organic phase was collected by separation. The aqueous phase was then extracted with dichloromethane (50 mL × 2), and the organic phases were combined. The combined organic phases were washed successively with saturated brine (100 mL × 2), dried over anhydrous sodium sulfate, filtered, and concentrated to dryness under reduced pressure to obtain 4.6 g of a pale yellow crude product, with a crude product yield of 91.0%.

[0029] The crude product was purified by silica gel column chromatography (stationary phase: 200-mesh silica gel, column diameter: 5 cm, silica gel usage: 80 g). The mobile phase was a petroleum ether-ethyl acetate mixture, with gradient elution: first, elution was performed with petroleum ether:ethyl acetate = 10:1 (v / v) for 2 column volumes to remove nonpolar impurities; then, elution was performed with petroleum ether:ethyl acetate = 5:1 (v / v) for 3 column volumes; finally, elution was performed with petroleum ether:ethyl acetate = 3:1 (v / v), and the target product fraction was collected (TLC monitoring, Rf ≈ 0.3, developing solvent: petroleum ether:ethyl acetate = 3:1). The target fractions were combined, concentrated under reduced pressure, and dried to obtain 4.4 g of nitrosamine impurity ripivirine, with a yield of 87.5%.

[0030] In this embodiment, N-nitroso-p-toluenesulfonamide (N-NTS) was used as the nitrosating agent, and the reaction was carried out in a near-neutral, anhydrous organic solvent. The reaction time was 4 hours, and the yield was increased to 87.5%. At the same time, the mild reaction conditions avoided the damage of the sensitive groups of the substrate by strong acid and inhibited the formation of byproducts such as dimers.

[0031] The embodiments described above are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and modifications made by those skilled in the art based on the invention shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing nitrosamine impurities from ripivirine, characterized in that, The reaction route is as follows: ； The specific reaction steps are as follows: S1. Add rilpivirine to the solvent, stir and react; then add the nitrosating agent, and continue stirring and reacting; S2. After the reaction is complete, solvent is added to the reaction solution and extraction is performed to form an aqueous phase and an organic phase. The aqueous phase is removed, and the organic phase is washed with saturated brine. The washed organic phase is then dried under reduced pressure to obtain crude nitrosamine impurity ribavirin.

2. The method for preparing nitrosamine impurities of lipivorelin according to claim 1, characterized in that, The solvent in step S1 is one of dichloromethane, dimethyl sulfoxide, and acetonitrile.

3. The method for preparing nitrosamine impurities of lipivorelin according to claim 1, characterized in that, The solvent in step S2 is an organic solvent, which can be one of ethyl acetate, dichloromethane, or toluene.

4. The method for preparing nitrosamine impurities of lipivorelin according to claim 1, characterized in that, In step S1, after adding lipavirin to the solvent, an acid is added. The acid can be one or more of acetic acid, phosphoric acid, and hydrochloric acid.

5. The method for preparing nitrosamine impurities of lipivorelin according to claim 1, characterized in that, The nitrosating agent is one of sodium nitrite, tert-butyl nitrite, isoamyl nitrite, or N-nitroso-p-toluenesulfonamide.

6. The method for preparing nitrosamine impurities of lipivorelin according to claim 1, characterized in that, The solvent in step S1 is a mixture of dichloromethane and tetrahydrofuran.

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