Method for mutual conversion between seneciocin and seneciocin n-oxide

Abstract

A method for mutual conversion between seneciocin and seneciocin N-oxide. Seneciocin is dissolved in a suitable solvent, concentrated hydrogen peroxide is added, and after stirring, seneciocin N-oxide can be obtained quantitatively. Seneciocin N-oxide is dissolved in a suitable solvent, sodium triacetylborohydride is added, and after stirring, seneciocin can be obtained quantitatively. Detection is carried out by liquid chromatography, by using 0.1% phosphoric acid in water-acetonitrile as the mobile phase, a detection wavelength of 215 nm, a flow rate of 1.0 mL / min, and a column temperature of 30°C, which can successfully identify the mutual conversion between the two compounds. The present method is simple, fast, and controllable, and enables quantitative conversion between the two.

Description

Methods for the interconversion of senglitinine and senglitinine nitrogen oxides Technical Field

[0001] This invention relates to a method for identifying semolina and semolina nitrogen oxides in Panax notoginseng using high performance liquid chromatography, preparative liquid chromatography, and nuclear magnetic resonance spectroscopy, as well as to the interconversion of semolina and semolina nitrogen oxides through redox reactions. Background Technology

[0002] Pyrrolizidine alkaloids (PAs) are common secondary metabolites found in plants of the Boraginaceae, Asteraceae, Orchidaceae, Apocynaceae, and Fabaceae families. They serve as a defense mechanism for plants against herbivores and insects. To date, over 660 PAs and their nitrogen oxides (PANOs) have been identified in approximately 3% of the world's flowering plants. Large quantities of PAs enter the human body through the food chain (such as grains, meat, milk, eggs, and honey), accumulating over time and causing toxicity. The 2020 edition of the Chinese Pharmacopoeia includes eight medicinal materials containing PAs, including Senecio scandens, Tussilago farfara, Eupatorium fortunei, and Lithospermum erythrorhizon, involving dozens of compound preparations. Furthermore, the Ministry of Health's Drug Standards and Drug Registration Standards include over 200 other PA-containing preparations.

[0003] Li Shuhua et al. isolated a relatively large amount of semolina alkaloid and semolina alkaloid nitrogen oxide from the tuberous roots of *Gynostemma pentaphyllum* [Li Shuhua, Chen Fengzheng, Tian Chong et al., A new monoterpene acid compound in *Gynostemma pentaphyllum*, Chinese Journal of Medicinal Chemistry, 2021, 31(12): 994-1000]. Semolina alkaloid and semolina alkaloid nitrogen oxide are very representative PAs compounds of the above-mentioned pyrrolizidine alkaloids. In addition to being naturally present in plants, PAs nitrogen oxide can also be generated in vivo by the metabolism of PAs proto-alkaloids through flavin monooxygenase and CYP450 enzymes. Due to its greater polarity, it is easily excreted from the body and was once thought to be less toxic than the proto-alkaloids. In plants or organisms, semolina alkaloid can be converted into semolina alkaloid nitrogen oxide, but the above conversion mainly occurs in organisms, and its conversion mechanism is only speculative and has not yet been confirmed. At present, there are no research reports on the interconversion of semolina alkaloid and semolina alkaloid nitrogen oxide through chemical methods.

[0004] Summary of the Invention

[0005] This invention provides a method for the interconversion of senglitinide and senglitinide nitrogen oxides.

[0006] Includes the following steps:

[0007] (1) The conversion of senilidinine into senilidinine nitrogen oxides:

[0008] Sesaminine is dissolved in a suitable solvent, and then 10 to 1000 times the molar amount of oxidant is added. After stirring for 2 to 50 hours, the semaphorinine is quantitatively converted into semaphorinine nitrogen oxides by high performance liquid chromatography.

[0009] (2) The nitrogen oxides of senglitinine are converted into senglitinine:

[0010] The nitrogen oxides of senglitinine were dissolved in a suitable solvent, and then 1 to 20 times the molar amount of reducing agent was added. The mixture was stirred for 1 to 40 hours, and the nitrogen oxides of senglitinine were quantitatively converted into senglitinine by liquid chromatography.

[0011] (3) The products of the above interconversion can be obtained by preparing liquid chromatography to obtain compounds with a purity greater than 98%, which meets the requirements of reference standards.

[0012] The appropriate solvent described in step (1) is methanol, ethanol, acetonitrile, or a mixture thereof.

[0013] The preferred oxidant according to step (1) is hydrogen peroxide.

[0014] The amount of hydrogen peroxide used as the oxidant in step (1) is 100 times the molar amount.

[0015] The preferred stirring reaction time according to step (1) is 30 hours.

[0016] The reducing agent described in step (2) is preferably sodium triacetylborohydride.

[0017] The preferred amount of sodium triacetylborohydride reducing agent described in step (2) is 10 times.

[0018] The preferred solvent according to step (2) is isopropanol.

[0019] The preferred stirring reaction time according to step (2) is 20 hours.

[0020] The high-performance liquid chromatography (HPLC) detection conditions according to claim 1 are as follows: using 0.1% phosphoric acid water-acetonitrile as the mobile phase, the detection wavelength is 215 nm, the flow rate is 1.0 ml / min, and the column temperature is 30 °C, which can successfully identify the interconversion between the two. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 is a high-performance liquid chromatogram of the conversion of the target compound of the present invention, senglitinine, with senglitinine nitrogen oxides;

[0023] Figure 2 is the 1H NMR spectrum of the target compound of this invention, senglitinine.

[0024] Figure 3 is the carbon NMR spectrum of the target compound of this invention, senglitinine.

[0025] Figure 4 is the 1H NMR spectrum of the target compound, senglitinide alkaloid oxide, of this invention;

[0026] Figure 5 is the carbon NMR spectrum of the target compound, senglitinide alkaloid oxide, of this invention; Detailed Implementation

[0027] The following will describe the implementation of the present invention in detail with reference to the embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve technical effects and to implement it accordingly.

[0028] Example 1

[0029] Take 1 gram of senglitinine and disperse it in 10 ml of methanol. Then add 50 ml of concentrated hydrogen peroxide dropwise. Stir at room temperature and monitor the liquid phase. After the reaction is basically complete and has lasted for 30 hours, stop the reaction. Extract the reaction solution twice with 50 ml of dichloromethane. Concentrate the aqueous solution to dryness. Then dissolve the concentrate in 20 ml of methanol and recrystallize to obtain senglitinine nitrogen oxides.

[0030] Example 2

[0031] Take 1 gram of senglitinine nitrogen oxide and disperse it in 100 ml of isopropanol. Then add 10 grams of sodium triacetylborohydride and stir at room temperature for 4 hours. Add another 10 grams of sodium triacetylborohydride and continue stirring at room temperature for 16 hours, then stop the reaction. Concentrate the reaction solution to dryness, then disperse the concentrate in 50 ml of water. Extract the aqueous solution twice with 50 ml of dichloromethane, concentrate to dryness after dichloromethane extraction, then dissolve the concentrate in 20 ml of acetone and recrystallize to obtain senglitinine.

[0032] The foregoing description illustrates and describes several preferred embodiments of the invention. However, as previously stated, it should be understood that the invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the invention should be within the protection scope of the appended claims.

Claims

1. A method for the interconversion of senglitinide and its nitrogen oxides, characterized by the following process steps: (1) The conversion of senilidinine into senilidinine nitrogen oxides: Sesaminine was dissolved in a suitable solvent, and then 10 to 1000 times the molar amount of oxidant was added. After stirring for 2 to 40 hours, the semaphorinine was quantitatively converted into semaphorinine nitrogen oxides by high performance liquid chromatography. (2) The nitrogen oxides of senglitinine are converted into senglitinine: The nitrogen oxides of senglitinine were dissolved in a suitable solvent, and then 1 to 10 times the molar amount of reducing agent was added. The mixture was stirred for 1 to 30 hours, and the nitrogen oxides of senglitinine were quantitatively converted into senglitinine by liquid chromatography. (3) The products of the above interconversion can be obtained by preparing liquid chromatography to obtain compounds with a purity greater than 98%, which meets the requirements of reference standards.

2. The suitable solvent according to claim 1 is methanol, ethanol, acetonitrile, chloroform, dichloromethane, diethyl ether, or a mixture thereof.

3. The oxidant according to claim 1 is preferably hydrogen peroxide.

4. The reducing agent according to claim 1 is preferably sodium triacetylborohydride.

5. The high performance liquid chromatography detection conditions according to claim 1 are as follows: using 0.1% phosphoric acid water-acetonitrile as the mobile phase, the detection wavelength is 215 nm, the flow rate is 1.0 ml / min, and the column temperature is 30 °C, which can successfully identify the interconversion between the two.

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