Intermediate compound, preparation method thereof and application of intermediate compound in preparation of Herbarulide

Abstract

The invention discloses an intermediate compound, a preparation method of the intermediate compound and application of the intermediate compound in preparation of Herbarulide. The structural formula of the intermediate compound is shown in the specification. When the intermediate compound is used for preparing Herbarulide, the use of HgO can be avoided, and the reaction process only needs to be carried out at normal temperature and normal pressure, so that the energy consumption is reduced, and meanwhile, the equipment requirement is also reduced. Meanwhile, when the intermediate is used for preparing Herbarulide, the yield can reach 85% or above.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to an intermediate compound, its preparation method, and its application in the preparation of Herbarulide. Background Technology

[0002] In the field of natural product chemistry, 5,6-epoxy-5,6-sterols have always been a research hotspot due to their unique structural features and broad biological activities (such as antibacterial activity). Among them, Herbarulide, a ketodivinyl lactone steroid compound with a novel homo-6-oxoergosterane skeleton, has attracted much attention since its first isolation from the endophytic fungus Pleospora herbarum in 1999 due to its unique chemical structure and potential biological activities. However, its structure was initially proposed based on spectroscopic analysis, which contained uncertainties, especially regarding the assignment of the C24 stereoconfiguration, leading to confusion in subsequent studies between Herbarulide and the structurally similar Fortisterol. To confirm its true structure and achieve efficient synthesis, chemical synthesis has become a key approach.

[0003] In the existing technology, Duecker et al. ( Org. Light. 2020 22 A synthetic route based on a biomimetic free radical rearrangement strategy (1585, DOI:10.1021 / acs.orglett.0c00180.) was reported, achieving the synthesis of Herbarulide through a four-step reaction using commercially available ergosterol as the starting material. The key step in this route involves the epoxidation and ring-opening reaction of Burawoy ketone (compound 8) with mercuric oxide (HgO) and iodine (I2) to generate a 5,6-epoxy-5,6-open ring-steroid intermediate (compound 11). Although the route is relatively short overall, it has significant drawbacks: First, HgO is a highly toxic reagent, posing serious risks to the environment and operator health, and its availability and disposal are increasingly restricted; second, the reaction process requires high temperatures, which not only increases energy consumption but may also lead to side reactions, affecting product purity and yield. The high temperatures also place higher demands on the reaction equipment, further increasing the difficulty and cost of industrial production.

[0004] Furthermore, while this synthetic route has made progress in structural confirmation, the use of HgO limits its potential for large-scale production and industrial application. Therefore, there is an urgent need to develop a novel synthetic method that avoids the use of HgO, has mild reaction conditions, and is easily scalable, in order to overcome the shortcomings of existing technologies and achieve efficient and sustainable synthesis of Herbarulide. Summary of the Invention

[0005] This invention aims to address at least one of the technical problems existing in the prior art. To this end, this invention proposes an intermediate compound that can provide a new route for the efficient and sustainable synthesis of Herbarulide.

[0006] The present invention also proposes a method for preparing the above-mentioned compounds.

[0007] This invention also proposes the application of the above-mentioned compound in the preparation of Herbarulide.

[0008] According to one aspect of the present invention, an intermediate compound is provided, the structural formula of which is as follows: .

[0009] The intermediate compounds according to embodiments of the present invention have at least the following beneficial effects: when synthesizing Herbarulide using the compounds of the present invention, there are significant improvements in safety, operability, and economy. Specifically, this is reflected in the following aspects: 1) Significant improvement in safety: By designing a novel catalytic cyclization strategy, the indispensable HgO / I2 oxidation system in the existing technology has been successfully replaced. This innovation significantly reduces a series of problems caused by mercury, such as extreme toxicity, high environmental hazards, high toxicity, strong bioaccumulation, and complex post-processing, thus improving the safety of the synthesis process; 2) Greatly simplified operability: The core cyclization reaction does not require HgO, a reagent that is extremely difficult to obtain, and can be carried out smoothly at room temperature and pressure, overcoming the limitation of traditional free radical reactions that require heating to higher temperatures. This not only reduces equipment requirements and energy consumption, but also makes process control simpler and more stable, making it more suitable for large-scale production; 3) Economic breakthrough: Based on the above improvements, the yield of Herbarulide prepared from this intermediate can reach over 85%. This high yield proves the high efficiency and atom economy of the new reaction route, significantly reducing raw material costs and laying a solid foundation for the industrial preparation of Herbarulide and related analogues.

[0010] According to another aspect of the present invention, a method for preparing the above-mentioned intermediate compound is also provided, comprising the following steps: S1, with Preparation of raw materials ; S2, with Preparation of raw materials ; S3, with Preparation of raw materials ; In the formula, R1 and R2 are independently selected from C1-6 alkyl groups.

[0011] According to some embodiments of the present invention, R1 and R2 are independently selected from at least one of ethyl or propyl.

[0012] According to some embodiments of the present invention, the preparation reaction in step S1 specifically includes making... It undergoes an acylation reaction with an acylation agent.

[0013] According to some embodiments of the present invention, the acylating agent includes at least one of acetic anhydride, acetyl chloride, or propionic anhydride.

[0014] According to some embodiments of the present invention, the preparation reaction conditions of step S1 include at least one of the following conditions: 1) the reaction is carried out in the presence of a catalyst, the catalyst including an organic base catalyst (such as 4-dimethylaminopyridine (DMAP), triethylamine or pyridine, etc.); 2) the reaction temperature is 15 ~ 35 ℃; 3) the reaction time is 1 ~ 3 h.

[0015] According to some embodiments of the present invention, the preparation reaction in step S2 specifically includes making... It reacts with Jones' reagent.

[0016] According to some embodiments of the present invention, the preparation reaction conditions of step S2 include at least one of the following conditions: 1) the reaction temperature is 15 ~ 35 ℃; 2) the reaction time is 8 ~ 12 h; 3) the reaction is carried out under stirring at a stirring speed of 400 ~ 600 rpm (e.g., 500 rpm).

[0017] According to some embodiments of the present invention, the preparation reaction in step S3 specifically includes the removal of The acyl group in it.

[0018] According to some embodiments of the present invention, the preparation reaction in step S3 specifically includes making It reacts with dibutyltin hydrogen.

[0019] According to some embodiments of the present invention, the preparation reaction conditions of step S3 include at least one of the following conditions: 1) the solvent of the reaction system is at least one of methanol or chloroform; 2) the reaction is carried out under reflux; 3) the reaction time is 8-12 h.

[0020] According to another aspect of the invention, the use of the above-mentioned intermediate compound in the preparation of Herbarulide is also provided.

[0021] According to some embodiments of the present invention, a method for preparing Herbarulide includes the following steps: Using the above intermediate as a raw material, Jones reagent is added, and the reaction proceeds to obtain the final product.

[0022] According to some embodiments of the present invention, the reaction conditions for the preparation of Herbarulide include at least one of the following: 1) a reaction temperature of 15-35 °C; 2) a reaction time of 15-45 min; and 3) a solvent for the reaction system being at least one of acetone or dichloromethane. The reaction can be carried out at room temperature without additional heating, simplifying experimental equipment requirements and reducing energy consumption. The reaction time is shortened to approximately 30 minutes, and the yield can reach 85%, achieving a higher product yield while significantly improving reaction efficiency. Furthermore, this reaction system can use acetone as a solvent, while existing technologies typically require benzene as the reaction solvent. Using acetone significantly reduces solvent toxicity.

[0023] According to another aspect of the invention, the use of the above-mentioned intermediate compound in the preparation of antifungal drugs is also provided.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0025] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available. Unless otherwise specified, the same parameter value is the same in all embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] In the description of this invention, references to terms such as "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0027] In the description of this invention, the use of terms such as "first," "second," etc., is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0028] Unless otherwise specified, "room temperature" in this embodiment of the invention means 25°C.

[0029] Unless otherwise specified, "about" in this invention means that the allowable error is within ±2%.

[0030] This invention provides a preparation route for Herbarulide. When the acylating agent is acetic anhydride, the specific preparation route is as follows: .

[0031] The triol compounds in the following examples Refer to Duecker et al. ( Org. Easy. 2020 22 The preparation was prepared according to the report of , 1585, DOI:10.1021 / acs.orglett.0c00180.).

[0032] Specifically, ergosterol (1.0 g, 2.534 mmol) was dissolved in 25 ml of dichloromethane, and potassium carbonate (1.4 g, 5.076 mmol) was dissolved in 25 ml of water. The ergosterol solution was added to the potassium carbonate solution, and 85% m-chloroperbenzoic acid (0.51 g, 2.534 mmol) was added to 10 ml of dichloromethane solution. The mixture was sonicated until dissolved. This solution was then added dropwise to the reaction mixture over five minutes. The mixture was stirred vigorously at room temperature for 45 minutes. The phases were separated, and the aqueous phase was extracted three times with dichloromethane. The combined organic phases were washed successively with saturated sodium bicarbonate solution and brine solution, dried over anhydrous sodium sulfate, and then the solvent was removed under reduced pressure to obtain a yellow solid epoxide.

[0033]

[0034] 1 H NMR (400 MHz, CDCl3) δ 5.49 – 5.39 (m, 1H), 5.28 – 5.11 (m, 2H), 3.97 (ddt, J = 15.7, 11.3, 4.4 Hz, 1H), 3.03 (d, J = 4.1 Hz, 1H), 2.27 (dd, J=13.1, 11.6 Hz, 1H), 2.09 – 1.93 (m, 5H), 1.88 – 1.81 (m, 2H), 1.76 – 1.67 (m,2H), 1.62 – 1.51 (m, 3H), 1.49 – 1.39 (m, 3H), 1.35 – 1.24 (m, 4H), 1.04 (s, 3H), 1.02 (d, J = 7.0 Hz, 3H), 0.93 (d, J = 6.8 Hz, 3H), 0.85 (d, J = 6.5 Hz, 3H), 0.83 (d, J = 7.0 Hz, 3H), 0.57 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 148.0, 135.4, 132.1, 114.8, 68.4, 66.9,55.6, 54.9, 54.6, 42.8, 42.2, 41.3, 40.4, 39.8, 38.6, 34.9, 33.5, 33.1, 31.2,27.9, 23.2, 21.1, 20.9, 20.0, 19.7, 17.6, 16.4, 12.0. Further, the epoxy compound (1 g, 2.427 mmol) obtained by the above operation was dissolved in a mixed solution of 1M potassium hydroxide aqueous solution (10 ml) and isopropanol (10 ml). The suspension was heated to 80°C and stirred for 18 hours. The reaction mixture was cooled to 25°C and neutralized with 1M hydrochloric acid aqueous solution. The layers were separated, and the aqueous phase was extracted with chloroform:isopropanol = 4:1 (3 * 15 ml). The organic phase was washed with brine, dried, and evaporated to dryness to obtain a yellow solid triol compound.

[0035]

[0036] 13 C NMR (101 MHz, DMSO- d 6) δ 140.1, 135.9, 131.8, 119.9, 74.9, 72.6,66.4, 55.8, 54.6, 43.4, 42.7, 42.5, 40.7, 40.5, 39.4, 37.1, 32.9, 31.7, 28.2,23.1, 21.8, 21.5, 20.2, 19.9, 18.2, 17.8, 12.5. 1 H NMR (400 MHz, DMSO- d 6) δ 5.28 – 5.12 (m, 2H), 5.12 – 5.06 (m, 1H), 4.51 (d, J = 5.5 Hz, 1H), 4.25 (d, J = 5.5 Hz, 1H), 3.84 – 3.70 (m, 1H), 3.60 (s,1H), 3.40 – 3.36 (m, 1H), 2.07 – 1.91 (m, 3H), 1.91 – 1.75 (m, 3H), 1.74 –1.57 (m, 2H), 1.54 – 1.38 (m, 6H), 1.34 – 1.17 (m, 6H), 1.00 (d, J = 6.6 Hz,3H), 0.91 (s, 3H), 0.89 (d, J = 6.8 Hz, 3H), 0.81 (d, J = 5.6 Hz, 3H), 0.80 (d, J =6.4 Hz, 3H), 0.55 (s, 3H). Example 1 In this example, a compound was prepared, and the structural formula of the compound is as follows: .

[0037] Its preparation process is as follows: S1, Preparation

[0038]

[0039] The triol compound (300 mg, 0.655 mmol) was dissolved in solution, and acetic anhydride (215 μL, 2.292 mmol) and 4-dimethylaminopyridine (279 mg, 2.292 mmol) were added. The mixture was stirred at room temperature for 2 hours. After the reaction was monitored by TLC to ensure complete reaction, the solution was evaporated to dryness and passed through a column to obtain a white solid. The yield of this reaction was calculated to be 90%, and its structure was confirmed by NMR as follows: .

[0040] 1 H NMR (500 MHz, CDCl3) δ 5.28 – 5.10 (m, 4H), 4.84 (dt, J= 5.2, 1.9Hz, 1H), 2.08 (s, 3H), 2.05 (s, 3H), 1.96 – 1.83 (m, 5H), 1.79 – 1.68 (m,3H), 1.62 – 1.53 (m, 5H), 1.51 – 1.41 (m, 2H), 1.35 – 1.28 (m, 5H), 1.08 (s,3H), 1.04 (d, J = 6.6 Hz, 3H), 0.94 (d, J = 6.9 Hz, 3H), 0.86 (d, J = 7.0 Hz, 3H), 0.84 (d, J = 7.3 Hz, 3H), 0.60 (s, 3H). 13 C NMR (126 MHz, CDCl3) δ 170.6, 170.4, 145.7, 135.4, 132.1, 114.0,74.9, 73.6, 70.8, 55.9, 54.8, 43.8, 43.2, 42.9, 40.4, 39.2, 37.3, 35.6, 33.1,32.2, 27.9, 26.9, 22.8, 21.9, 21.4, 21.4, 21.1, 20.0, 19.7, 18.1, 17.6, 12.4. S2, Preparation

[0041]

[0042] The starting material (300 mg, 0.584 mmol) was dissolved in 4 mL of acetone, and Jones' reagent (550 μL, 1.518 mmol) was slowly added. The mixture was stirred overnight at room temperature (500 rpm). After the reaction was complete (monitored by TLC), the reaction was quenched with isopropanol, diluted with water, extracted with ethyl acetate, washed with brine, dried over anhydrous sodium sulfate, and column chromatography to obtain a yellow solid. The yield of this reaction was calculated to be 48%, and its structure was confirmed by NMR as follows: .

[0043] 1 H NMR (500 MHz, CDCl3) δ 5.76 – 5.68 (m, 1H), 5.26 (dd, J = 15.3, 7.7Hz, 1H), 5.16 (dd, J= 15.3, 8.4 Hz, 1H), 4.87 – 4.78 (m, 1H), 4.06 (s, 1H), 2.33 – 2.27 (m, 2H), 2.19 – 2.12 (m, 1H), 2.07 (s, 3H), 2.10 – 2.02 (m, 1H),2.00 – 1.94 (m, 1H), 1.91 – 1.75 (m, 6H), 1.68 – 1.62 (m, 1H), 1.61 – 1.45(m, 5H), 1.41 – 1.33 (m, 3H), 1.08 (s, 3H), 1.04 (d, J = 6.5 Hz, 3H), 0.94 (d, J = 6.7 Hz, 3H), 0.86 (d, J = 8.0 Hz, 3H), 0.84 (d, J = 7.3 Hz, 3H), 0.64 (s, 3H). 13 C NMR (126 MHz, CDCl3) δ 171.0, 166.4, 159.1, 135.0, 132.6, 115.1,103.7, 70.1, 58.0, 56.3, 51.6, 46.5, 42.9, 42.8, 42.1, 40.4, 39.9, 35.5,33.1, 27.8, 26.6, 25.2, 23.1, 21.3, 21.0, 20.0, 19.7, 17.6, 17.6, 12.5. S3, Preparation

[0044]

[0045] The starting material (70 mg, 0.143 mmol) and dibutyltin hydroxide (20 mg, 0.072 mmol) were dissolved in 2.5 mL of methanol and refluxed overnight. After the reaction was confirmed to be complete by TLC, the solution was evaporated to dryness and purified by column chromatography. The yield of this reaction was calculated to be 87%, and its structure was confirmed by NMR as follows: .

[0046] 1 H NMR (500 MHz, CD3OD) δ 5.62 (t, J = 1.8 Hz, 1H), 5.29 (dd, J= 15.2, 7.6 Hz, 1H), 5.22 (dd, J = 15.3, 8.2 Hz, 1H), 3.68 (tt, J = 11.5, 4.5 Hz, 1H),2.34 (ddd, J = 12.8, 4.7, 2.1 Hz, 1H), 2.30 – 2.26 (m, 1H), 2.26 (s, 1H), 2.14 – 2.04 (m, 2H), 2.02 – 1.93 (m, 2H), 1.89 (p, J = 6.9 Hz, 2H), 1.85 – 1.76 (m,2H), 1.72 – 1.57 (m, 2H), 1.56 – 1.34 (m, 7H), 1.07 (d, J = 6.6 Hz, 3H), 1.04(s, 3H), 0.97 (d, J = 6.9 Hz, 3H), 0.89 (d, J = 6.8 Hz, 3H), 0.87 (d, J = 6.8 Hz, 3H), 0.68 (s, 3H). 3 C NMR (126 MHz, CD3OD) δ 168.5, 160.9, 135.3, 132.2, 114.0, 105.2, 66.9, 57.7, 56.2, 51.8, 46.2, 44.5, 43.0, 42.6, 40.4, 39.8, 35.6, 33.0, 29.9,27.6, 24.8, 22.7, 20.2, 19.1, 18.7, 16.8, 16.6, 11.5. Example 2 This example provides a method for preparing Herbarulide, as detailed below: The product obtained in Example 1 (20 mg, 0.045 mmol) was dissolved in 2 mL of acetone, and Jones' reagent (53 μL, 0.135 mmol) was added to the reaction solution. The reaction was carried out at room temperature for half an hour. After the reaction was completed by TLC, the solution was quenched with isopropanol, diluted with water, extracted with ethyl acetate, washed with brine, dried over anhydrous sodium sulfate, and purified by rotary evaporation and column chromatography. The yield of this reaction was calculated to be 85%, and its structural formula was confirmed by NMR as follows: .

[0047] 1 H NMR (500 MHz, CDCl3) δ 5.77 (s, 1H), 5.75 (s, 1H), 5.27 (dd, J =15.2, 7.8 Hz, 1H), 5.16 (dd, J = 15.2, 8.5 Hz, 1H), 2.58 – 2.53 (m, 1H), 2.51(s, 1H), 2.49 – 2.41 (m, 1H), 2.22 (ddd, J = 14.1, 5.0, 2.2 Hz, 1H), 2.17 (dd, J = 12.1, 7.0 Hz, 1H), 2.14 – 2.09 (m, 1H), 2.09 – 2.02 (m, 1H), 1.99 (dd, J =14.1, 5.6 Hz, 1H), 1.87 (dt, J = 11.5, 5.5 Hz, 2H), 1.83 – 1.74 (m, 1H), 1.70(td, J = 13.2, 4.0 Hz, 1H), 1.60 (d, J = 17.7 Hz, 1H), 1.55 – 1.46 (m, 3H), 1.46– 1.37 (m, 2H), 1.26 (s, 3H), 1.04 (d, J = 6.6 Hz, 3H), 0.94 (d, J = 6.9 Hz, 3H),0.86 (d, J = 7.1 Hz, 3H), 0.83 (s, 3H), 0.66 (s, 3H). 13 C NMR (126 MHz, CDCl3) δ 198.5, 173.9, 162.5, 159.5, 134.7, 132.8,114.7, 113.3, 58.1, 56.3, 47.2, 47.0, 42.8, 40.4, 40.3, 39.1, 33.9, 33.2,33.0, 29.7, 27.7, 25.4, 22.6, 21.1,20.0, 19.7, 17.6, 12.5. The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An intermediate compound, characterized in that, The structural formula of the intermediate compound is as follows: 。 2. The method for preparing the intermediate compound as described in claim 1, characterized in that, Includes the following steps: S1, with Preparation of raw materials ; S2, with Preparation of raw materials ; S3, with Preparation of raw materials ; In the formula, R1 and R2 are independently selected from C1-6 alkyl groups.

3. The method for preparing the intermediate compound according to claim 2, characterized in that, The preparation reaction in step S1 specifically includes making... It undergoes an acylation reaction with an acylation agent.

4. The method for preparing the intermediate compound according to claim 2, characterized in that, The preparation reaction in step S2 specifically includes making... It reacts with Jones' reagent.

5. The method for preparing the intermediate compound according to claim 2, characterized in that, The preparation reaction in step S3 specifically includes making... It reacts with dibutyltin hydrogen.

6. The method for preparing the intermediate compound according to any one of claims 2 to 5, characterized in that, The preparation reaction conditions of step S1 include at least one of the following conditions: 1) the reaction is carried out in the presence of a catalyst, the catalyst including an organic base catalyst; 2) the reaction temperature is 15 ~ 35 ℃; 3) the reaction time is 1 ~ 3 h; and / or, the preparation reaction conditions of step S2 include at least one of the following conditions: 1) the reaction temperature is 15 ~ 35 ℃; 2) the reaction time is 8 ~ 12 h; 3) the reaction is carried out under stirring at a stirring speed of 400 ~ 600 rpm; and / or, the preparation reaction conditions of step S3 include at least one of the following conditions: 1) the solvent of the reaction system is at least one of methanol or chloroform; 2) the reaction is carried out under reflux; 3) the reaction time is 8 ~ 12 h.

7. The use of the intermediate compound as described in claim 1 in the preparation of Herbarulide.

8. A method for preparing Herbarulide, characterized in that, Includes the following steps: Using the intermediate as described in claim 1 as a raw material, Jones reagent is added, and the reaction is carried out to obtain the product.

9. The method for preparing Herbarulide according to claim 8, characterized in that, The preparation reaction conditions of Herbarulide include at least one of the following conditions: 1) the reaction temperature is 15 ~ 35 ℃; 2) the reaction time is 15 ~ 45 min; 3) the solvent of the reaction system is at least one of acetone or dichloromethane.

10. The use of the intermediate compound as described in claim 1 in the preparation of antibacterial drugs.

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