A preparation method of maytansine DM1 polymer

Abstract

The present invention discloses a method for preparing a maytansine DM1 polymer. The present invention provides a method for preparing a compound as shown in formula I, comprising the following steps: in a solvent, DM1 is subjected to an oxidation reaction as shown below to obtain a compound as shown in formula I, wherein the solvent is an amide solvent or a mixed solvent of an amide solvent and water. The preparation method of compound I disclosed in the present invention has simple process, easy operation, high yield and low cost.

Description

Technical Field

[0001] The invention relates to a method for preparing a maytansine DM1 polymer. Background Art

[0002] DM1 is the abbreviation of a key compound in a series of antibody-coupled drug (ADC) drugs (N2'-deacetyl-N2'-(3-mercapto-1-oxopropyl) maytansine (DM1). During the synthesis and preparation process of this compound, a maytansine DM1 polymer such as the compound shown in Formula I will be produced. The compound shown in Formula I is an impurity in the preparation process of DM1, and its control during the preparation and post-treatment processes is critical. The study and preparation of the compound shown in Formula I is of great significance for selecting a suitable method to effectively control and remove such impurities, which is of great significance for improving the quality of DM1 and even ADC drugs.

[0003]

[0004] The document J.Med.Chem.2006,49,4392-4408 reports a method for preparing a compound as shown in Formula I: at room temperature, 2,2'-disulfide dipyridine and other reagents are used to dehydrogenate and polymerize DM1 in the presence of phosphate buffer solution and ethanol to generate a dimer as shown in Formula I, and finally the compound as shown in Formula I is prepared and purified by HPLC. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the problems of complex operation and high cost in the existing preparation method of DM1 polymer compound I. The present invention provides a preparation method of maytansine DM1 polymer that is different from the prior art. The method has a simple process, is easy to operate and has low cost.

[0006] The present invention provides a method for preparing a compound as shown in Formula I, comprising the following steps: subjecting DM1 to an oxidation reaction as shown below in a solvent to obtain a compound as shown in Formula I, wherein the solvent is an amide solvent, or a mixed solvent of an amide solvent and water;

[0007]

[0008] In the preparation method, the amide solvent can be a conventional amide solvent in the art that does not affect the reaction (for example, a solvent in which all the other groups except the amide structure are saturated alkyl or cycloalkyl), such as one or more of 1,3-dimethyl-2-imidazolidinone DMI, dimethylformamide and dimethylacetamide, more preferably dimethylformamide and / or 1,3-dimethyl-2-imidazolidinone.

[0009] In a certain embodiment, the solvent is preferably a mixed solvent of an amide solvent and water.

[0010] In the preparation method, in the mixed solvent, the volume ratio of the amide solvent to water is preferably 1:1 to 1:10, such as 1:1 or 1:4, more preferably 1:1 to 1:4.

[0011] In the preparation method, the amount of the solvent is not limited as long as it does not affect the reaction. The mass volume ratio of the DM1 to the amide solvent is preferably 1:10 g / mL to 1:40 g / mL, such as 1:26.7 g / mL and 1:40 g / mL, more preferably 1:20 g / mL to 1:40 g / mL.

[0012] In the preparation method, the reaction temperature is the conventional temperature of this type of oxidation reaction in the art, and the reaction temperature of the reaction is generally 0°C to 150°C.

[0013] In the preparation method, when the solvent is an amide solvent, those skilled in the art will appreciate that when the reaction temperature is low (e.g., room temperature), the reaction time must be greatly increased to increase the conversion rate of the compound shown in Formula I. When the solvent is an amide solvent, the reaction temperature is preferably 70°C to 150°C, more preferably 75°C to 85°C (e.g., 80°C).

[0014] In the preparation method, when the solvent is a mixed solvent of an amide solvent and water, the conversion rate of compound I is greatly accelerated, and compound I can be completely converted into compound I at room temperature. When the solvent is an amide solvent and water, the reaction temperature of the reaction is generally 0°C to 80°C (e.g., room temperature (10°C to 30°C)), more preferably 15 to 25°C.

[0015] In the preparation method, the oxidation reaction can be carried out under inert gas protection, and the gas protection can be conventional gas protection in the art, such as argon protection. Experimental results show that whether the reaction is carried out under argon protection has no effect on the yield and purity of the reaction.

[0016] In the preparation method, the progress of the reaction can be monitored by conventional monitoring methods in the art (such as TLC, HPLC), and the disappearance or no-reaction of compound DM1 is generally taken as the reaction endpoint. The reaction time can be 1-72 hours, such as 1h, 31h and 72h.

[0017] In a certain embodiment of the present invention, the solvent is 1,3-dimethyl-2-imidazolidinone and water, and the reaction temperature is room temperature.

[0018] In a certain embodiment of the present invention, the raw materials for the oxidation reaction only include DM1, an amide solvent or an amide solvent and water.

[0019] In the preparation method, the post-treatment of the reaction can adopt the conventional post-treatment of this type of reaction, which includes the following steps: after the oxidation reaction is completed, cooling and crystallizing in the presence of water, filtering, and obtaining the compound shown in formula I.

[0020] Without violating the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0021] The reagents and raw materials used in the present invention are commercially available.

[0022] The positive progressive effect of the present invention is that the method is simple in process and easy to operate, and can be used for impurity control in the DM1 production process, which is of great significance for improving the quality of DM1. DETAILED DESCRIPTION

[0023] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0024] Example 1

[0025] 1. Synthesis of Compounds

[0026] 150 mg of DM1 was added to 4 mL of 1,3-dimethyl-2-imidazolidinone, heated to 80°C with stirring for 31 hours, cooled to room temperature, 15-20 mL of water was added, stirred and cooled to about 0°C, filtered, washed with water to obtain 100 mg of a white solid, eluted with a 1×10 cm silica gel column, dichloromethane / methanol (20 / 1), to obtain 85 mg of a white solid dimer compound I, HPLC: 94.6% (measured by the area normalization method).

[0027] 1H NMR (400MHz, DMSO) δ7.17(d,J=1.2Hz,1H),6.87(s,1H),6.69–6.44(m,3H),5.91(s,1H),5.68–5.47(m,1H),5.31(q,J=6.6 Hz,1H),4.54(dd,J=12.0,2.5Hz,1H),4.08(t,J=11.8Hz,1H),3.94(s,3H),3.50(d,J=9.0Hz,1H),3.45(d,J=12.4Hz,1H), 3.27(s,3H),3.18(d,J=12.5Hz,1H),3.10(s,3H),2.84–2.74(m,2H),2.70(s,3H),2.57–2.45(m,4H),2.05(d,J=12.1Hz,1 H),1.60(s,3H),1.46(d,J=12.9Hz,2H),1.27(d,J=3.4Hz,1H),1.18(d,J=6.8Hz,3H),1.13(d,J=6.3Hz,3H),0.79(s,3H).C 70 H 94 Cl 2 N 6 O 20 S 2 MS-ESI calculated value [M+1] + =1473.53, actual measured value 1473.56.

[0028] The HPLC detection method of compound I is as follows:

[0029] Mobile phase gradient table: mobile phase A: 0.05% phosphoric acid aqueous solution, mobile phase B: acetonitrile, mobile phase C: methanol.

[0030]

[0031] The retention time of DM1 was 25.666 min, and the retention time of compound I was 37.486 min.

[0032] 2. Compound detection conditions

[0033] Magnetic resonance spectroscopy: Instrument: AscendTM 400M Bruker nuclear magnetic resonance instrument;

[0034] HPLC analysis conditions: High performance liquid chromatograph equipped with PDA detector;

[0035] Column: Agilent Zorbax SB-phenyl, 4.6 × 150 mm, 5 μm;

[0036] Mobile phase A: 0.05% phosphoric acid aqueous solution, mobile phase B: acetonitrile, mobile phase C: methanol;

[0037] Detection wavelength: 220 nm, flow rate: 1.0 mL / min, injection volume: 10 μL;

[0038] Sample concentration: 1.0 mg / mL, column temperature: 30°C, running time: 55 min.

[0039] Example 2

[0040] Put 100 mg of DM1 into 4 mL of dimethylformamide, heat to 80°C with stirring for 31 hours, cool to room temperature, add 15-20 mL of water, cool to about 0°C with stirring, filter, wash with water to obtain 100 mg of white solid, use 1×10 cm silica gel column, dichloromethane / methanol (20 / 1) as eluent to obtain 65 mg of dimer compound I as a white solid, HPLC: 94.9% (measured by area normalization method).

[0041] Example 3

[0042] 150 mg DM1 was added to 4 mL dimethylformamide and stirred at room temperature for 72 hours. HPLC tracking showed that compound I was 40.0%, and the remaining unconverted raw material DM1 was 18.4%. Heat to 150°C for 4 hours until DM1 disappeared, cool to room temperature, add 15-20 mL water, stir and cool to about 0°C, filter, wash with water to obtain 80 mg of brown solid, use 1×10 cm silica gel column, dichloromethane / methanol (20 / 1) as eluent to obtain 55 mg of off-white solid dimer compound I, HPLC: 76.1% (measured by area normalization method).

[0043] Example 4

[0044] 150 mg of DM1 was added to 4 mL of dimethylacetamide, heated to 80°C with stirring for 1 hour, and HPLC liquid phase tracking showed that no obvious dimer compound I was generated. 16 mL of water was added, and the reaction was continued at 80°C for 24 hours until DM1 disappeared. The mixture was cooled to room temperature, 15-20 mL of water was added, and the mixture was cooled to about 0°C with stirring. The mixture was filtered and washed with water to obtain 115 mg of a white solid. The mixture was eluted with 1×10 cm silica gel column and dichloromethane / methanol (20 / 1) to obtain 75 mg of an off-white solid dimer compound I, HPLC: 85.3% (measured by area normalization method).

[0045] Example 5

[0046] 150 mg DM1 was added to a mixture of 4 mL 1,3-dimethyl-2-imidazolidinone and 4 mL water, and stirred at room temperature for 20 hours. HPLC tracking showed that DM1 had completely disappeared and a white solid gradually precipitated. 20 mL of water was added, stirred and cooled to about 0°C, filtered, and washed with water to obtain 120 mg of a white solid, dimer compound I, HPLC: 98.5% (measured by area normalization method).

[0047] Comparative Example 1

[0048] 150 mg of DM1 was added to 4 mL of 1,3-dimethyl-2-imidazolidinone and stirred at room temperature for 20 hours (HPLC tracking showed DM1 raw material: 93.1%, dimer compound I: 6.7%). HPLC tracking after 72 hours showed compound I was 10.5%, and the remaining unconverted raw material DM1: 89.4%.

[0049] Comparative Example 2 (refer to J.Med.Chem.2006,49,4392-4408)

[0050] 150 mg of DM1 was put into 30 mL of 1:1 (v / v) ethanol and 0.05 M phosphate buffer with pH = 7.5, and a mixture of 25 mg of 2,2'-dithiodipyridine and 6 mL of ethanol was added. The mixture was stirred at room temperature for 2 hours, and the solvent was evaporated under reduced pressure. The mixture was extracted with ethyl acetate, and the organic phase was washed with saturated sodium chloride. The solvent was evaporated under reduced pressure, and the residue was eluted with 1×10 cm silica gel column, dichloromethane / methanol (20 / 1) to obtain 65 mg of dimer compound I as a white solid, HPLC: 87.04% (area normalization method).

[0051] 1H NMR (400MHz, DMSO) δ7.18(s,1H),6.88(s,1H),6.64–6.48(m,3H),5.92(s,1H),5.66–5.49(m,1H),5.32(q,J=6.7Hz,1H),4.5 4(dd,J=12.0,2.5Hz,1H),4.08(t,J=11.9Hz,1H),3.94(s,3H),3.51(d,J=9.0Hz,1H),3.45(d,J=12.2Hz,1H),3.27(s,3H),3. 19 (d, J = 12.3 Hz, 1H), 3.10 (s, 3H), 2.80 (d, J = 9.5 Hz, 2H), 2.71 (s, 3H), 2.58–2.44 (m, 4H), 2.05 (d, J = 12.2 Hz, 1H), 1.60 (s, 3H), 1.46 (d, J = 12.9 Hz, 2H), 1.26 (d, J = 12.9 Hz, 1H), 1.18 (d, J = 6.8 Hz, 3H), 1.13 (d, J = 6.3 Hz, 3H), 0.79 (s, 3H). MS-ESI calculated value [M+1] + =1473.53, actual measured value 1473.56.

[0052] Comparative Example 3

[0053] 480 mg of DM1 was added to 38 mL of ethyl acetate solution, heated to about 70°C to dissolve, stirred at room temperature for 20 hours, and filtered to obtain 420 mg of white solid, dimer compound I, HPLC: 0.079%, DM1, HPLC: 99.06% (measured by area normalization method).

[0054] Comparative Example 4

[0055] 150 mg DM1 was added into 4 mL dichloromethane solution, dissolved, stirred at room temperature for 20 hours, concentrated under reduced pressure until the solvent was exhausted, a small amount of ethanol was added, stirred and filtered to obtain 120 mg of white solid, dimer compound I, HPLC: 0.07%, DM1, HPLC: 99.12% (measured by area normalization method).

Claims

1. A method for preparing a compound as shown in formula I, characterized in that: It includes the following steps: In a solvent, DM1 is subjected to an oxidation reaction as shown below to obtain a compound as shown in Formula I, wherein the solvent is an amide solvent, or a mixed solvent of an amide solvent and water; The amide solvent is one or more of 1,3-dimethyl-2-imidazolidinone, dimethylformamide and dimethylacetamide; In the mixed solvent, the volume ratio of the amide solvent to water is 1:1 to 1:10; When the solvent is an amide solvent, the reaction temperature of the reaction is 70°C to 150°C; When the solvent is an amide solvent and water, the reaction temperature is 0°C to 80°C.

2. The method for preparing the compound of formula I as claimed in claim 1, characterized in that: The solvent is a mixed solvent of an amide solvent and water.

3. The method for preparing the compound of formula I as claimed in claim 1, characterized in that: The mass volume ratio of the DM1 to the amide solvent is 1:10 g / mL to 1:40 g / mL.

4. The method for preparing the compound of formula I as claimed in claim 1, characterized in that: In the mixed solvent, the volume ratio of the amide solvent to water is 1:1 to 1:4; And / or, the mass volume ratio of the DM1 to the amide solvent is 1:20 g / mL to 1:40 g / mL.

5. The method for preparing the compound of formula I as claimed in claim 1, characterized in that: When the solvent is an amide solvent, the reaction temperature of the reaction is 75°C to 85°C; And / or, when the solvent is an amide solvent and water, the reaction temperature of the reaction is room temperature.

6. The method for preparing the compound of formula I as claimed in claim 1, characterized in that: It includes the following steps: In an amide solvent at a temperature of 80° C., DM1 is subjected to the oxidation reaction to obtain a compound as shown in Formula I; Alternatively, DM1 is subjected to the oxidation reaction in a mixed solvent having a volume ratio of 1:1 between an amide solvent and water at room temperature to obtain a compound as shown in Formula I.

7. The method for preparing the compound of formula I according to any one of claims 1 to 6, characterized in that: The raw materials for the oxidation reaction only include DM1, amide solvent or amide solvent and water.

8. The method for preparing the compound of formula I according to any one of claims 1 to 6, characterized in that: The post-treatment of the reaction comprises the following steps: after the oxidation reaction is completed, cooling and crystallizing in the presence of water, filtering, and obtaining the compound shown in formula I.

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