Process for the preparation of micheliolide derivatives

Abstract

The present application firstly discovers the 3S-isomer of DMAMCL, and studies an effective method for controlling the content of the 3S-isomer (less than 0.4%) to ensure that the 3S-isomer can be used to prepare the ACT001 compound meeting the scalar standard.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical preparation, specifically relating to a method for preparing a micranthin derivative. Background Technology

[0002] ACT001 is the fumarate form of dimethylamino micranthin (DMAMCL), a micranthin derivative synthesized via the dimethylamino Michael addition reaction of micranthin (MCL). ACT001 is an orally active PAI-1 inhibitor that inhibits the phosphorylation of PI3K and AKT, and directly binds to STAT3 to inhibit STAT3 phosphorylation and PD-L1 expression. ACT001 can cross the blood-brain barrier and exhibits potent anti-glioblastoma (GBM) activity and immunomodulatory effects.

[0003] ACT001 is synthesized from ternolactone (PTL) through a three-step chemical reaction. Most of its chiral centers come from the main raw material PTL, with only one chiral center being synthesized (MCL→DMAMCL).

[0004]

[0005] Literature reports that chiral centers synthesized during the preparation of DMAMCL via the addition reaction of MCL with dimethylamine are mostly in the R configuration, with no reports of the S configuration (3S-isomer). This invention confirms the formation of this 3S-isomer during the addition reaction, and that this isomer is introduced into ACT001, thus affecting the product quality of ACT001. Further research revealed that if commercially available dimethylaminetetrahydrofuran (2.0M) is used for direct addition with MCL, the 3S-isomer content is approximately 1.0%, exceeding the scalar standard (isomer content not greater than 0.1%) after salt formation. Therefore, further exploration and research are needed to control the addition isomer, ensuring its content in DMAMCL is below 0.4% to guarantee that the corresponding monoimide content in the final product is less than 0.1%. Summary of the Invention

[0006] To improve the above-mentioned technical problems, the present invention provides a method for preparing dimethylamino micranthin (DMAMCL), comprising the following step 2: under low temperature conditions, dissolving compound MCL and dimethylamine hydrochloride in an organic solvent, and then adding an organic amine to obtain the compound DMAMCL.

[0007]

[0008] According to an embodiment of the invention, the low temperature is -20 to 15°C, for example -15 to 10°C, preferably -5 to 5°C or 0 to 5°C.

[0009] According to an embodiment of the present invention, the organic amine is selected from tertiary amines, such as triethylamine, DBU, DIEA, tripropylamine, DMAP, and tetramethyldiamine, or one or more of these.

[0010] According to an embodiment of the present invention, the organic solvent is selected from one or more of methanol, ethanol, isopropanol, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, diethyl ether, methyl tert-butyl ether, ethyl acetate, toluene, acetonitrile, DMF, dichloromethane, chloroform, and acetone.

[0011] According to an embodiment of the present invention, the addition can be done in batches or by dripping.

[0012] According to an embodiment of the present invention, the molar ratio of MCL to dimethylamine hydrochloride is 1:(1-5), for example 1:(1.5-3), such as 1:2 or 1:2.5;

[0013] According to an embodiment of the present invention, the reaction time is 1-48 hours, for example 2-6 hours, such as 2.5 hours, 3 hours, 3.5 hours, 4 hours, or 4.5 hours.

[0014] According to an embodiment of the present invention, the method can control impurities (3S-isomers) with the following structures:

[0015]

[0016] According to an embodiment of the present invention, the method can control the content of impurities to be below 0.4%, for example below 0.35%, below 0.3%, below 0.25%, below 0.2%, below 0.15%, or below 0.1%.

[0017] This invention also provides a method for preparing compound ACT001, comprising the following steps:

[0018]

[0019] Step 2: Prepare DMAMCL according to the method described above.

[0020] Step 3: Compound DMAMCL is dissolved in an aqueous solution of fumaric acid to react and give compound ACT001.

[0021] According to an embodiment of the present invention, an organic solvent may be added to the aqueous solution of fumaric acid in step 3, such as acetone.

[0022] This invention also provides a method for preparing compound ACT001, comprising the following steps:

[0023]

[0024] Step 2: Under low temperature conditions, compound MCL and dimethylamine hydrochloride are dissolved in an organic solvent, and then an organic amine is added to obtain the compound DMAMCL;

[0025] Step 3: Compound DMAMCL is dissolved in an aqueous solution of fumaric acid to react and give compound ACT001;

[0026] According to an embodiment of the present invention, in step 2, the low temperature is -20 to 15°C, for example -15 to 10°C, preferably -5 to 5°C or 0 to 5°C.

[0027] According to an embodiment of the present invention, in step 2, the organic amine is selected from one or more of tertiary amines, such as triethylamine, DBU, DIEA, tripropylamine, DMAP, and tetramethyldiamine.

[0028] According to an embodiment of the present invention, the organic solvent in step 2 is selected from chlorinated solvents, such as dichloromethane and trichloromethane;

[0029] According to an embodiment of the present invention, in step 2, the addition can be done in batches or by dripping.

[0030] According to an embodiment of the present invention, in step 2, the molar ratio of MCL to dimethylamine hydrochloride is 1:(1-5), for example 1:(1.5-3), such as 1:2 or 1:2.5;

[0031] According to an embodiment of the present invention, in step 2, the reaction time is 1-48 hours, for example 2-6 hours, such as 2.5 hours, 3 hours, 3.5 hours, 4 hours, or 4.5 hours.

[0032] According to an embodiment of the present invention, an organic solvent may be added to the aqueous solution of fumaric acid in step 3, such as acetone.

[0033] According to an exemplary embodiment of the present invention, a method for preparing the compound DMAMCL includes the following steps:

[0034] At 0–5°C, dimethylamine hydrochloride, MCL and water (or without water) are added to dichloromethane, stirred, and the temperature is controlled at 0–5°C. TEA solution is added dropwise, and the reaction is carried out at 0–5°C to obtain the dimethylamine micranthin (DMAMCL).

[0035] According to an embodiment of the present invention, the preparation method further includes a post-processing step: after the reaction is completed, water and a 20% HCl aqueous solution are added, and the mixture is separated; a 10% NaOH solution is added to the aqueous phase, and the product is precipitated from the water. After filtration, washing, and drying, dimethylamino micranthin (DMAMCL) is obtained.

[0036] According to an embodiment of the present invention, the preparation method of compound MCL includes the following step 1: compound PTL undergoes a rearrangement reaction under the action of a catalyst to obtain compound MCL;

[0037]

[0038] According to an embodiment of the present invention, the catalyst is selected from p-toluenesulfonic acid (PTSA), such as p-toluenesulfonic acid monohydrate.

[0039] According to an embodiment of the present invention, step 1 may further include a purification step 1-1: recrystallizing the obtained compound MCL in acetone to obtain the purified compound MCL.

[0040] Beneficial effects

[0041] This invention is the first to discover the 3S-isomer of DMAMCL through experiments. The preparation method provided by this invention can effectively control the content of the 3S isomer (less than 0.4%), thereby ensuring that it can be used to prepare the ACT001 compound that meets the scalar standard. Attached Figure Description

[0042] Figure 1 3S-isomer 1 H NMR spectrum.

[0043] Figure 2 3S-isomer 13 C10 NMR spectrum.

[0044] Figure 3 The spectrum of DEPT135 for the 3S-isomer is shown.

[0045] Figure 4 The COSY spectrum of the 3S-isomer is shown.

[0046] Figure 5 The HMBC spectrum of the 3S-isomer is shown.

[0047] Figure 6 The HSQC spectrum of the 3S-isomer is shown. Detailed Implementation

[0048] The technical solutions of this disclosure will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of this disclosure and should not be construed as limiting the scope of protection of this disclosure. All technologies implemented based on the above content of this disclosure are covered within the scope of protection intended by this disclosure.

[0049] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0050] Unless otherwise stated, the content of the 3S isomers involved in this invention is calculated using the area normalization method.

[0051] The preparation method for synthesizing ACT001 in this embodiment of the invention mainly involves the following reaction route:

[0052]

[0053] Example 1: Preparation method of compound MCL

[0054] Under nitrogen protection, at 20±5℃, 600g of dichloromethane (DCM) and 7.5g of p-toluenesulfonic acid monohydrate were added to a reaction flask. While maintaining the temperature at 20±5℃, a solution of 300g of PTL in 2700g of dichloromethane (DCM) was slowly added dropwise. After the addition was complete, the reaction continued at 20±5℃ until the percentage of PTL was less than or equal to 3.0%. After the reaction was complete, an aqueous solution of NaHCO3 / H2O was slowly added to the system, followed by stirring, standing, and separation. The organic phase was collected, washed with NaCl / H2O solution, separated, filtered, dissolved, and dried to obtain crude micranthin (MCL). Under nitrogen protection, 600g of acetone and crude MCL were added to a reaction flask, stirred, and heated until clear. The mixture was then cooled, crystallized, filtered, washed, and dried to obtain 117g of purified MCL with an HPLC purity of 98.833%.

[0055] Example 2: Preparation of compound DMAMCL

[0056] General method: At 0–5℃, dimethylamine hydrochloride (DMA.HCl), MCLA, and water (or without water) are added to dichloromethane, stirred, and the temperature is controlled at 0–5℃. TEA / DCM solution is added dropwise, and the reaction is continued at 0–5℃. The degree of reaction is detected using HPLC. After complete conversion of the raw materials, the solvent is removed under reduced pressure. After solvent removal, the product is redissolved in dichloromethane, washed with water, and separated. The organic phase is added to water and a 20% HCl aqueous solution, and separated. The organic phase is washed with DCM, separated, and the aqueous phase is collected and solvent removed. The obtained aqueous phase is added to a 10% NaOH solution, and the product precipitates from the water. After filtration, washing, and drying, dimethylamino micranthin (DMAMCL) is obtained. Characterization data of its 3S isomer are shown in [reference needed]. Figures 1 to 6 .

[0057] Detailed operating procedures:

[0058] 1 Ingredients

[0059] 1.1 Weigh 24.80g of triethylamine and 202.66g of dichloromethane; stir well and set aside.

[0060] 1.2 Preparation of 20% hydrochloric acid solution: Prepare a 20% hydrochloric acid aqueous solution (101.11g of 36% hydrochloric acid and 86.67g of purified water) in a plastic bucket, and cool it to room temperature for later use.

[0061] 1.3 Preparation of 10% sodium hydroxide aqueous solution: Prepare a 10% sodium hydroxide aqueous solution (dissolve 19.95g of sodium hydroxide and 180.25g of purified water in a plastic bucket until clear) and cool to room temperature after the solid is completely dissolved.

[0062] 2 reactions

[0063] 2.1 Add 200.12g of dichloromethane solution, 40.45g of MCL, 126.62g of DMA.HCl and 4mL of water to a 1L four-necked glass reaction flask and start stirring.

[0064] 2.2 Start the cryogenic coolant circulation pump to begin cooling down to 0-5℃.

[0065] 2.3 When the temperature drops to 0-5℃, add the prepared TEA / DCM solution dropwise into the reaction solution, and the addition will be completed in about 1.5 hours.

[0066] 2.4 After the drop is completed, maintain the reaction at 0-5℃ and stir for at least 5-6 hours.

[0067] 2.5 Sampling control (HPLC monitoring: take the reaction solution, dry it with cold air, and send it for testing; Michelolone should not exceed 5.0%), MCL: 2.831%, 3S-isomer 0.137%.

[0068] 3 Post-processing

[0069] 3.1 After confirming the reaction is complete, add 120.15 g of water to the reaction solution, stir, and wash. The mixture separates into layers; discard the aqueous phase and collect the organic phase.

[0070] 3.2 Add 200.38 g of purified water to the organic phase; under stirring conditions, control the temperature at 15–25 °C, and adjust the pH of the reaction solution to 2–3 using a prepared 20% hydrochloric acid solution (consuming 42.79 g); after adjustment, continue stirring for 15 minutes, and after retesting the pH and finding no change, stop stirring, allow the mixture to stand and separate into layers, retain the aqueous phase, and discard the dichloromethane phase; wash the aqueous phase once with 100.01 g of dichloromethane, collect the aqueous phase, and discard the dichloromethane phase; concentrate the aqueous phase under reduced pressure at below 25 °C for at least 40–60 minutes (no fractions after concentration).

[0071] 3.3 After concentration, cool the aqueous phase to 0-10℃, and use the prepared 10% sodium hydroxide solution (consuming 61.85g) to adjust the pH of the aqueous phase to 9-10; after reaching the required pH value, adjust the temperature to 0-5℃ and stir and keep warm for 1 hour.

[0072] 3.4 After the heat preservation is completed, filter the cake and wash it twice with purified water (80mL×2). Then, dry the cake until no more liquid drips.

[0073] 3.5 The obtained product was placed in a tray and vacuum dried at a temperature of 55±5℃ and a vacuum degree of -0.08 to -0.1MPa for at least 15 hours. Approximately 40.35g of product was obtained, which was a white or off-white powder with 0.05% isomers.

[0074] 3.6 Pack into pharmaceutical low-density polyethylene bags, and then seal the outer layer with a polyester / aluminum / polyethylene pharmaceutical packaging composite bag, and temporarily store at 2-8℃.

[0075] 3.7 Yield: Approximately 84%

[0076] Adjust the reaction parameters of the above method according to the following table to prepare compound DMAMCL:

[0077]

[0078]

[0079]

[0080] Example 3: Preparation of compound ACT001

[0081] Mix acetone and DMA·MCL and stir until completely dissolved, then filter and set aside.

[0082] Dissolve fumaric acid (FA) in a mixed solvent of acetone and water, stir until clear, and filter for later use.

[0083] Add acetone and water to the reaction vessel, stir and heat to 30±5℃. First, add 1 / 2 of the acetone-fumarate aqueous solution to the reaction system, maintain the temperature at 30±5℃, and then simultaneously add the specified amount of DMA·MCL acetone solution and acetone-fumarate aqueous solution. After the addition is complete, add seed crystals to suspend and grow crystals. Then add the remaining acid and alkali solutions. After the addition is complete, keep warm, cool down, filter, wash and dry the ACT001 product.

[0084]

[0085] Preparation of compound DMAMCL (Comparative Example 1)

[0086] Dichloromethane was added to the reaction flask, stirred, and cooled to 0–5°C. Sodium hydroxide was weighed and added to the reaction flask, maintaining the temperature at 0–5°C. Dimethylamine hydrochloride was weighed and added to the reaction flask, and stirred at 0–5°C until all dimethylamine hydrochloride on the surface of the reaction solution disappeared. Stirring was stopped, and the mixture was allowed to stand and separate into layers. The supernatant was collected and used directly for the addition reaction. DMA / DCM solution was weighed and added to the reaction flask, maintaining the reaction temperature at 0–5°C. MCL was added and stirred until HPLC detection showed MCL ≤ 5%. Then, the product DCM was dissolved, washed with water, and acidified. The layers were separated, and the aqueous phase was collected. DCM was removed from the aqueous phase again, and the mixture was alkali-treated, filtered, washed with water, and dried to obtain the DMA / MCL product.

[0087]

[0088] As shown in the table above, when using free DMA aqueous solution as raw material, the content of 3S-isomers generated in the reaction solution exceeds 2%, which does not meet the requirements for preparing qualified ACT001 (3S-isomer content less than 0.4%).

[0089] When NaOH is used as a base to react with DMA.HCl to prepare a DMA / DCM solution, and then reacts with MCL, the content of 3S-isomers generated in the reaction solution exceeds 1%. Although lowering the reaction temperature and adjusting the amount of DMA can reduce the content of 3S-isomers to some extent, the content of 3S-isomers in the reaction solution is still far greater than 0.4%, and there is also the problem of incomplete reaction of the raw materials.

[0090] Comparative Example 2

[0091] Following the method of Example 3, using DMAMCL with a 3S isomer content of 0.96% as raw material, the ACT001 prepared had a 3S-isomer content of 0.16%.

[0092] The above description provides an exemplary account of the implementation methods of the technical solution disclosed herein. It should be understood that the scope of protection of this disclosure is not limited to the above-described embodiments. Any modifications, equivalent substitutions, or improvements made by those skilled in the art within the spirit and principles of this disclosure should be included within the scope of protection of the claims of this application.

Claims

1. A method for preparing dimethylamino Michelia lactone (DMAMCL), comprising the following steps: Dimethylamine hydrochloride, MCLA and water were added to dichloromethane at 0~5℃, stirred, and the temperature was controlled at 0~5℃. Triethylamine / dichloromethane solution was added dropwise, and the reaction was carried out at 0~5℃ to obtain the dimethylamine micranthin. The molar ratio of MCL to dimethylamine hydrochloride is 1:(1-5); The reaction time is 1-48 hours; The method controls the impurity content of the following structures to be below 0.4%: .

2. The preparation method according to claim 1, characterized in that, The molar ratio of MCL to dimethylamine hydrochloride is 1:(1.5-3); And / or, the reaction time is 2-6 hours.

3. The preparation method according to claim 1, characterized in that, The preparation method also includes a post-processing step: after the reaction is complete, water and a 20% HCl aqueous solution are added, and the mixture is separated; a 10% NaOH solution is added to the aqueous phase, and the product is precipitated from the water. After filtration, washing, and drying, dimethylamino micranthin is obtained.

4. A method for preparing compound ACT001, comprising the following steps: Step 2: Prepare compound DMAMCL according to the preparation method described in any one of claims 1-3; Step 3: Compound DMAMCL is dissolved in an aqueous solution of fumaric acid to react and give compound ACT001.

5. The preparation method according to claim 4, characterized in that, In step 3, an organic solvent, namely acetone, is also added to the aqueous solution of fumaric acid.

6. The preparation method according to claim 4, characterized in that, The preparation method of compound MCL includes the following steps:

1. Compound ternolactone PTL undergoes a rearrangement reaction under the action of a catalyst to obtain compound MCL; The catalyst is p-toluenesulfonic acid.

7. The preparation method according to claim 6, characterized in that, The catalyst is p-toluenesulfonic acid monohydrate; And / or, step 1 further includes a purification step 1-1: recrystallizing the obtained compound MCL in acetone to obtain the purified compound MCL.

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