A method for the synthesis of everolimus

Abstract

The application provides a preparation method of everolimus, and the method comprises the following steps: (1) under alkaline conditions, a compound A sirolimus is reacted with an active ester B in an organic solvent to obtain a compound C, which is an intermediate of sirolimus 43 and 28 hydroxyl diether; the reaction temperature is 50-70 DEG C; (2) the compound C is subjected to acid hydrolysis reaction in a solvent to obtain a compound D everolimus, and the reaction temperature is -20-0 DEG C. The preparation method simplifies the process operation process, and has a good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of medicine, and particularly relates to a preparation method of Everolimus. BACKGROUND

[0002] Everolimus (RADO01, see the following figure for the structure) is a macrolide immunosuppressant and antitumor drug, which is derived from C43-OH of sirolimus (formerly known as rapamycin) to C43-O-(2-hydroxyethyl), so Everolimus is also called 43-O-(2-hydroxyethyl)-rapamycin; the molecular formula thereof is C 53 H 83 NO 14 , the molecular weight is 958.24, and the CAS# is 159351-69-6.

[0003] Everolimus is developed by Novartis, Switzerland, and the related compound patent application started in 1997. In 2003, it was first approved for marketing in Sweden and used in combination with cyclosporine for preventing and treating acute and chronic rejection in kidney and heart transplantation. With the elucidation of mTOR and cell growth and metabolic functions, the application of Everolimus in tumors and rare diseases is developed, and multiple indications are successively approved: 1) estrogen receptor positive, HER2 negative breast cancer, 2) neuroendocrine tumor, 3) renal cell carcinoma after failure of sunitinib and sorafenib treatment, 4) tuberous sclerosis (TSC) related renal angiomyolipoma, 5) TSC related subependymal giant cell astrocytoma, 6) TSC related epilepsy, etc.

[0004]

[0005] Everolimus is prepared by using sirolimus (formerly known as rapamycin) as a raw material, carrying out a single etherification reaction with an active ester side chain to form an Everolimus precursor, and finally carrying out deprotection.

[0006] At present, the synthesis of Everolimus mainly has the following two methods:

[0007] Method one: the method disclosed in patents US5665772, WO9409010, CN201010017955 and CN201511030109, in which an active ester side chain is used, and a single etherification reaction is carried out with the C43 hydroxyl group of sirolimus in the presence of a base to form an Everolimus precursor, and then the precursor is deprotected to obtain Everolimus.

[0008] Method two: the method disclosed in patents CN102268015A, CN103848849A, CN105254646A, etc., with sirolimus as raw material, first, the hydroxyl group at C28 of sirolimus is protected to obtain a sirolimus derivative, then in the presence of a base, the hydroxyl group at C43 of the derivative is reacted with an active ester to form an intermediate by monoetherification, and then the intermediate is deprotected to obtain everolimus. SUMMARY

[0009] The technical problem to be solved by the present application is to provide a new synthetic preparation method of everolimus, which simplifies the process operation process and has good industrial application prospect.

[0010] The present application is implemented as follows:

[0011] A synthetic preparation method of everolimus, the steps of the method are as follows:

[0012] (1) under alkaline conditions, compound A sirolimus is reacted with active ester B in an organic solvent to obtain compound C, which is an intermediate of double etherification of hydroxyl groups at positions 43 and 28 of sirolimus; the reaction temperature is 50-70°C, and the reaction formula 1 is as follows:

[0013]

[0014] wherein P is a protecting group;

[0015] (2) compound C is hydrolyzed by acid in a solvent to obtain compound D everolimus, the reaction temperature is -20-0°C, and the reaction formula 2 is as follows:

[0016]

[0017] Further, the base in the alkaline condition of step (1) is one or more of diethylamine, triethylamine, N,N-diisopropylethylamine, pyridine, and 2,6-dimethylpyridine.

[0018] Further, the organic solvent in step (1) is toluene or xylene.

[0019] Further, the protecting group P in step (1) is silane SiR1R2R3, wherein R1, R2 and R3 can be independently H or C1-C6 alkane, but not H at the same time.

[0020] Further, the reaction temperature of step (1) is 57-63°C; and the step (1) is carried out under inert gas protection.

[0021] Further, the molar ratio of compound A to active ester B in step (1) is 1:2-1:15; and the molar ratio of active ester B to base is 1:1-1:1.5.

[0022] Further, the active ester B is trifluoromethanesulfonic acid-2-[tert-butyldimethylsilyl]ethyl ester.

[0023] Further, the concentration of the sirolimus in the reaction system of step (1) is 0.01-1.0 mol / L.

[0024] Further, the acid in step (2) is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid and acetic acid; and the solvent is one or more of acetone, methanol, ethanol, acetonitrile or aqueous solution thereof.

[0025] Further, the acid in step (2) is 0.15-0.3 mol / L of hydrochloric acid; and the reaction temperature of step (2) is-15-0℃.

[0026] The present application has the following advantages:

[0027] The preparation method of the everolimus provided by the present application adopts simultaneous alkylation reaction of the 28- and 43-position hydroxyl groups of sirolimus, and selectively hydrolyzes the ether at the 28-position to obtain everolimus. Compared with the prior art, the present application provides a new preparation method, simplifies the process operation procedure, and has good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0028] The present application will be further described below with reference to the accompanying drawings and examples.

[0029] Figure 1 H-NMR spectrum of the compound D in Example 3 of the present application. 1 H-NMR spectrum of the compound D in Example 3 of the present application.

[0030] Figure 2 H-NMR spectrum of the compound D in Example 3 of the present application. 13 H-NMR spectrum of the compound D in Example 3 of the present application.

[0031] Figure 3 HPLC chart of the compound D in Example 3 of the present application. DETAILED DESCRIPTION

[0032] The present application relates to a preparation method of everolimus, comprising the following steps:

[0033] (1) under the protection of inert gas, organic solvent, sirolimus and base are sequentially added, and then active ester is added, and the reaction is carried out under heating, after the reaction is completed, cooling, filtration, washing, separation and purification are carried out to obtain the intermediate of double etherification of sirolimus at 43- and 28-position hydroxyl groups.

[0034] The organic solvent is toluene or xylene, preferably toluene; the base is one or more of diethylamine, triethylamine, N,N-diisopropylethylamine, pyridine, 2,6-lutidine, preferably N,N-diisopropylethylamine; the active ester is 2-[tert-butyldimethylsilyl]ethyl trifluoromethanesulfonate; the amount of active ester added is 2-15 molar equivalents of sirolimus; the amount of base added is 1-1.5 molar equivalents of active ester; the concentration of sirolimus in the reaction system is 0.01-1.0 mol / L; the reaction temperature is 50-70°C, preferably 57-63°C; and the eluent used in the separation and purification of the crude product is n-heptane:acetone=95:5 to 85:15 (v / v).

[0035] (2) The intermediate of the bis-etherification of sirolimus C43 and C28 hydroxyl groups is subjected to acid hydrolysis in a solvent, and after the reaction is completed, extraction and concentration are performed to obtain a crude everolimus, which is subjected to separation and purification to obtain pure everolimus.

[0036] The solvent is acetone, methanol, ethanol, acetonitrile or an aqueous solution thereof, preferably acetonitrile or an aqueous solution thereof; the acid is hydrochloric acid, sulfuric acid, phosphoric acid, formic acid or acetic acid, preferably 0.15-0.3 mol / L of hydrochloric acid; the reaction temperature is -20-0°C, preferably -15-0°C. The stationary phase used in the separation and purification is spherical normal-phase silica gel; and the eluent used in the separation and purification is a mixed solvent of ethyl acetate and n-heptane, in particular ethyl acetate:n-heptane=51:49 to 60:40 (v / v).

[0037] The technical solutions of the present application will be described clearly and completely below in conjunction with the accompanying Figures 1-3 and specific embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts fall within the scope of protection of the present application. The specific conditions not mentioned in the embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturers. The reagents or instruments not mentioned by the manufacturers are all conventional products that can be purchased on the market.

[0038] Example 1, Preparation of Compound C

[0039]

[0040] 2 g of sirolimus, 3.5 mL of N-ethyldiisopropylamine, 4.72 g of 2-(tert-butyldimethylsilyl)oxyethanol trifluoromethanesulfonate, and 20 mL of toluene were added to a 100 mL round-bottom flask. The mixture was magnetically stirred at 60 °C, and the reaction was monitored by thin-layer chromatography (TLC) until complete. The reaction solution was cooled and filtered under reduced pressure. The residue was washed with 90 mL of a mixed solvent (ethyl acetate: n-heptane = 1:2 v / v) until it turned white. The filtrates were combined and transferred to a separatory funnel. The mixture was washed once with 40 mL of 0.5 mol / L dilute hydrochloric acid, four times with 40 mL of purified water until the solution was neutral, and once with 40 mL of saturated sodium chloride solution. The solution was then subjected to silica gel column chromatography (eluent: acetone: n-heptane = 8:92 v / v) to collect the desired fraction. The solution was concentrated to dryness at 33-38 °C to give 1.4 g of compound C.

[0041] HRMS: C 67 H 115 NO 15 Si₂Na[M+Na] + : 1252.7704.

[0042] Example 2: Preparation of crude compound D

[0043]

[0044] 1.4 g of compound C and 15 mL of acetonitrile solvent were added to a 25 mL round-bottom flask. The mixture was pre-cooled to -10 °C and magnetically stirred. A mixture of 0.6 mL of 0.2 mol / L hydrochloric acid and 5 mL of acetonitrile was slowly added dropwise. The reaction was monitored by thin-layer chromatography (TLC) until complete. The reaction was quenched by adding sodium bicarbonate solution of equal concentration. The reaction solution was transferred to a separatory funnel, and 100 mL of ethyl acetate and 20 mL of purified water were added respectively. After shaking, the mixture was allowed to stand for separation. The aqueous phase was extracted a second time with 50 mL of ethyl acetate to remove the aqueous phase. The two organic phases were combined, washed once with 30 mL of purified water, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain 1.1 g of crude compound D.

[0045] Example 3: Preparation of pure compound D

[0046] 1.1 g of crude everolimus was dissolved in 2 ml of ethyl acetate and subjected to spherical silica gel column chromatography. The mobile phase was ethyl acetate:n-heptane = 51:49 to 60:40 (v / v). Fractions were collected, and the purified solutions were combined and concentrated to dryness under reduced pressure, yielding 0.6 g of pure compound D. Compound D was analyzed by HRMS and NMR, and it was found to be homologous to everolimus. The composition of compound D... 1 H-NMR spectrum as follows Figure 1 As shown, compound D 13 C-NMR spectra as follows Figure 2 As shown.

[0047] HRMS: C 53 H 83 NO 14 Na[M+Na] + : 980.57058.

[0048] The NMR detection results are shown in the following table:

[0049] Compound D (Everolimus) 1 H, 13 C-NMR chemical shift data attribution a、b (d6-DMSO)

[0050]

[0051]

[0052]

[0053] a 1 H and 13 CNMR was measured at 600MHz and 150MHz respectively

[0054] b Chemical shift values of main conformations

[0055] HPLC detection conditions: column: Hypersil BDS C18 column (5μm, 3mm*250mm), detection wavelength: UV 210nm, column temperature: 50℃, flow rate: 1.1mL / min, mobile phase A: 0.27g / L potassium dihydrogen phosphate solution = 40:60 (V / V); mobile phase B: acetonitrile, run at the proportion described in Table 1; the detection results are shown in Table 2. Figure 3

[0056] Table 1: mobile phase proportion running table

[0057] Time (min) Mobile phase A (%) Mobile phase B (%) 0～2 100 0 2～7 100→72 0→28 7～25 72→60 28→40 25～33 60→0 40→100 33～43 0 100

[0058] In summary, the preparation method of everolimus provided by the present application adopts simultaneous alkylation reaction of the 28- and 43-hydroxyl groups of sirolimus, and selectively hydrolyzes the ether at the 28-position to obtain everolimus. Compared with the prior art, the present application provides a new preparation method, simplifies the process operation procedure, and has good industrial application and promotion prospects.

[0059] ​While the foregoing description has described specific embodiments of the application, one ordinary skill in the art will appreciate that various modifications and changes can be made thereto without departing from the spirit and scope of the application, as set forth in the appended claims.

Claims

1. A method for synthesizing and preparing everolimus, characterized in that: The method steps are as follows: (1) Under alkaline conditions, compound A sirolimus reacts with active ester B in an organic solvent by heating to give compound C, which is the intermediate of sirolimus with hydroxyl groups at positions 43 and 28. The reaction temperature is 50-70℃, and the reaction formula is as follows: Wherein, P is a protecting group; The organic solvent is toluene or xylene; the molar ratio of compound A to active ester B is 1:2 to 1:15; the molar ratio of active ester B to alkali is 1:1 to 1:1.5; the active ester B is ethyl trifluoromethanesulfonate-2-[tert-butyldimethylsilyl]; the concentration of sirolimus in the reaction system is 0.01 to 1.0 mol / L. (2) Compound C undergoes acid hydrolysis in a solvent to give compound D, everolimus, at a reaction temperature of -20 to 0℃. The reaction equation is as follows:

2. The method for synthesizing and preparing everolimus as described in claim 1, characterized in that: The base in the alkaline conditions described in step (1) is one or more of diethylamine, triethylamine, N,N-diisopropylethylamine, pyridine, and 2,6-dimethylpyridine.

3. The method for synthesizing and preparing everolimus as described in claim 1, characterized in that: The protecting group P in step (1) is a silane SiR1R2R3, wherein R1, R2, and R3 can be H or C1 to C6 alkanes independently, but not all of them can be H at the same time.

4. The method for synthesizing and preparing everolimus as described in claim 1, characterized in that: The reaction temperature in step (1) is 57-63℃; step (1) is carried out under the protection of an inert gas.

5. The method for synthesizing and preparing everolimus as described in claim 1, characterized in that: The acid in step (2) is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid; the solvent is one or more of acetone, methanol, ethanol, acetonitrile, or their aqueous solutions.

6. The method for synthesizing and preparing everolimus as described in claim 1, characterized in that: The acid in step (2) is 0.15-0.3 mol / L hydrochloric acid; the reaction temperature in step (2) is -15 to 0℃.

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