Preparation method of PNU-159682

Abstract

The invention discloses a preparation method of PNU-159682 (PNU-159682). The invention provides a preparation method of a compound 7, and the preparation method of the compound 7 comprises the following step: in a solvent, in the presence of a catalyst and an organic alkali, carrying out a ring closing reaction as shown in the following formula on a compound 6 to obtain the compound 7. The preparation method disclosed by the invention has the advantages of low cost, high yield, mild reaction conditions and suitability for industrial large-scale production. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and specifically relates to a preparation method of PNU-159682. Background Art

[0002] Antibody drug conjugate (ADC) is a new type of highly effective biological drug that connects antibodies to small molecule cytotoxic payloads with biological activity through linkers. It is mainly used for the treatment of cancer and tumors. It has become a hot spot for development, and multiple ADCs are in different stages of clinical development. The principle is to connect cytotoxins to antibodies, and through the recognition of specific antigens on the surface of cancer cells by antibodies, enter cancer cells through endocytosis, and then transport cytotoxins to the target site to achieve the purpose of targeted treatment of malignant tumors. According to different mechanisms of action, toxins suitable for ADC are divided into microtubule inhibitors, DNA damaging agents, RNA polymerase inhibitors, etc.

[0003] Among them, PNU-159682 (CAS: 202350-68-3, structural formula as follows) is a metabolite of anthracycline neomycin, a DNA topoisomerase II inhibitor with excellent cytotoxicity. In ADC synthesis, PNU-159682 is a more effective and more tolerable ADC cytotoxin than doxorubicin, and can be used in EDV nanocell technology to overcome drug resistance.

[0004]

[0005] There are very few reports on the synthesis method of PNU-159682 in the prior art. Among them, there are only two reports on the ring-closing reaction using the compound (2S)-4-((2S,3S,4S,6R)-3-hydroxy-2-methyl-6-(((1S,3S)-3,5,12-trihydroxy-3-(2-hydroxyacetyl)-10-methoxy-6,11-dioxo-1,2,3,4,6,11-hexahydrotetraphenyl-1-yl)oxy)tetrahydro-2H-pyran-4-yl)-2-methoxymorpholine-4-oxide (CAS: 179484-51-6) as a raw material.

[0006] Patent WO1998002446A1 discloses the use of ferrous chloride tetrahydrate for the reaction. The synthesis method is shown in the following formula. The raw material input amount is milligram level, the reaction time is relatively long at 48 hours, and the yield is extremely low at only 6.7%. Obviously, this method is not suitable for industrial scale-up and cannot meet industrial needs.

[0007]

[0008] Patent WO2012073217A1 (Chinese equivalent CN103270043A) discloses the use of inorganic bases for the reaction, and its synthesis route is shown in the following formula. The raw materials of the patented method are milligram-level, and the reaction yield is low, only 50%, and the patent states that the reaction time is 20 minutes, which is relatively short. When the inventor repeated the method, he found that when the feed amount increased, the reaction was incomplete, the reaction time was extended, the system became complex, and a large amount of by-products were generated. It can be seen that this method cannot meet the needs of industrial scale-up.

[0009]

[0010] The intermediate nemorubicin is also commonly used in the preparation of compound PNU-159682. Patent WO2021031599 A1 discloses the preparation of PNU-159682 using nemorubicin as raw material. The synthesis method is shown in the following formula. The reaction process is long, requiring 4 steps, and the total yield is low at only 50% to 60%, which cannot meet the needs of industrial scale-up.

[0011]

[0012] There are two patents in the prior art that have publicly reported the synthesis method of nemorubicin hydrochloride. Among them, patent BE904431A discloses the following method, and its synthesis route is shown in the following formula. The patent method needs to use doxorubicin hydrochloride as a raw material. The price cost of doxorubicin hydrochloride is very expensive, and the post-processing operation of this method is complicated, and column purification is required, which not only has large losses, low yields, and poor atom economy, but also has a two-step column yield of 55%. Secondly, the patent points out that the reaction is quenched for 15 minutes, which is a short time, and there will be local heat release for this reaction, which is very uncontrollable in scale-up production. When the feed amount increases, a large amount of insoluble matter will be produced, which is not conducive to industrial scale-up production.

[0013]

[0014] Patent EP0434960A1 discloses the following method, and its synthesis route is shown in the following formula. The patented method also uses expensive doxorubicin hydrochloride as a raw material, and the cost is very high. The patent discloses that a large amount of iodide is added, requiring 15 equivalents, and the reaction time is long, requiring 36 hours; the post-processing operation is complicated, and column purification is required. The overall yield is low at only 45%, the atom economy is poor, the cycle is long, and it is not suitable for industrial scale-up.

[0015]

[0016] In summary, the preparation method of nemorubicin hydrochloride is complicated and expensive, which is very unfavorable for the mass production of PNU-159682. Therefore, designing and implementing a synthesis method of PNU-159682 that is suitable for industrial production, with mild conditions, simple operation and high yield has become the focus of research and development of those skilled in the art. Summary of the invention

[0017] The technical problem to be solved by the present invention is that the yield of PNU-159682 (i.e., compound 7 of the present invention) in the prior art is low, the cost is high, and it is not suitable for industrial production. To this end, the present invention provides a preparation method of PNU-159682. The preparation method of the present invention has the advantages of low cost, high yield, mild reaction conditions, and suitability for large-scale industrial production.

[0018] The present invention provides a method for preparing compound 7, which comprises the following step S6: in a solvent, in the presence of a catalyst and an organic base, subjecting compound 6 to a ring-closing reaction as shown in the following formula to obtain compound 7,

[0019]

[0020] The organic base is 2,6-diisopropylaniline and / or N,N-diisopropylethylamine (DIEA / DIPEA);

[0021] The solvent is a mixed solvent consisting of a nitrile solvent and an ether solvent.

[0022] In a preferred embodiment, in the method for preparing compound 7, certain conditions and operations have the following definitions, and the definitions of the conditions and operations not mentioned are as described in any embodiment of the present invention (this paragraph is hereinafter referred to as "in a preferred embodiment").

[0023] In a preferred embodiment, in step S6, the nitrile solvent is acetonitrile.

[0024] In a preferred embodiment, in step S6, the ether solvent is one or more of tetrahydrofuran, dioxane and ethylene glycol dimethyl ether, such as tetrahydrofuran.

[0025] In a preferred embodiment, in step S6, the volume ratio of the ether solvent to the nitrile solvent is (0.2-1):1; for example (0.5-0.7):1, and for example 0.6:1.

[0026] In a preferred embodiment, in step S6, the molar volume ratio of the compound 6 to the solvent is 1 mmol:(0.1-0.3)L, for example, 1 mmol:(0.1-0.2)L, and for example, 1 mmol:0.16L.

[0027] In a preferred embodiment, in step S6, the organic base is N,N-diisopropylethylamine.

[0028] In a preferred embodiment, in step S6, the molar ratio of the organic base to the compound 6 is (1-5):1, for example (1.5-3.5):1, and for example 3:1.

[0029] In a preferred embodiment, in step S6, the catalyst is a triazine compound, such as cyanuric chloride.

[0030] In a preferred embodiment, in step S6, the molar ratio of the catalyst to the compound 6 is (1-3):1, for example (1-2):1, and for example 1.5:1.

[0031] In a preferred embodiment, in step S6, the temperature of the ring-closure reaction is 5-25°C, such as 10-18°C, and another example is 15°C.

[0032] In a preferred embodiment, in step S6, the reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere.

[0033] In a preferred embodiment, in step S6, the ring-closure reaction is carried out under light-shielding conditions.

[0034] In step S6, the progress of the ring-closing reaction can be monitored by conventional monitoring methods in the art (e.g., HPLC, TLC, or LC-MS), and the disappearance or no-reaction of compound 6 is generally regarded as the reaction endpoint. The reaction time can be 2 to 7 hours, for example, 2 to 5 hours, and for example, 2 hours.

[0035] In a preferred embodiment, in step S6, after the ring-closure reaction is completed, the following post-treatment steps are also included. The post-treatment steps are conventional post-treatment operations for such reactions in the art, for example, including one or more of quenching, extraction, filtration, washing, drying, concentration and purification.

[0036] The quenching reagent may be an aqueous solution of 3-amino-1,2-propanediol (eg, 0.45 mol / L).

[0037] The quenching may include the following steps: reacting the mixture obtained after the ring-closure reaction with an aqueous solution of 3-amino-1,2-propanediol (eg, 0.45 mol / L).

[0038] The extraction solvent may be dichloromethane. The washing solution may be saturated saline. The drying agent may be anhydrous sodium sulfate. The purification may be column chromatography, and the eluent of the column chromatography may be dichloromethane and methanol, and the volume ratio of dichloromethane to methanol may be (120-500):1.

[0039] In a preferred embodiment, the preparation method of compound 7 comprises the following steps: under the protection of inert gas, compound 6 and a solvent are mixed, the temperature is controlled to 10 to 18° C., protected from light, an organic base is added and stirred to dissolve, cyanuric chloride is added, the temperature is controlled to 10 to 18° C. and the reaction is carried out for 2 to 7 hours, after the reaction is complete, 3-amino-1,2-propanediol aqueous solution is added to quench, water and dichloromethane are added to extract, and after the insoluble matter is precipitated, the product is filtered with diatomaceous earth, and the organic phase is washed, dried, concentrated, and column chromatographed to obtain the product.

[0040] In a preferred embodiment, the preparation method of compound 7 also includes the preparation method of compound 6, and the preparation method of compound 6 includes the following step S5: in a solvent, in the presence of an oxidant, subjecting compound 5 to an oxidation reaction as shown in the following formula to obtain compound 6,

[0041]

[0042] In a preferred embodiment, in step S5, the solvent is a chlorinated alkane organic solvent, such as one or more of dichloromethane, 1,2-dichloroethane and chloroform, and another example is dichloromethane.

[0043] In a preferred embodiment, in step S5, the molar volume of the compound 5 and the solvent is (1-30) mmol:1L, for example (10-20) mmol:1L, and for example 15.6 mmol:1L.

[0044] In a preferred embodiment, in step S5, the oxidant is selected from one or more of Jones reagent, Collins reagent, pyridinium chlorochromate, pyridinium dichromate, manganese dioxide, Dess-Martin periodinane, potassium permanganate, periodic acid, osmium tetroxide, 30% hydrogen peroxide, meta-chloroperbenzoic acid and tert-butyl hydroperoxide; for example, meta-chloroperbenzoic acid (m-CPBA).

[0045] In a preferred embodiment, in step S5, the molar ratio of the oxidant to the compound 5 is (1-3):1, for example (1-2):1, and for example 1.2:1.

[0046] In a preferred embodiment, in step S5, the oxidant is added at a temperature of -10 to 0°C, for example, at a temperature of -5°C.

[0047] In a preferred embodiment, in step S5, the oxidation reaction is carried out under light-proof conditions.

[0048] In a preferred embodiment, in step S5, the temperature of the oxidation reaction is -20 to 25°C, such as 0 to 5°C, and another example is 0°C.

[0049] In step S5, the progress of the oxidation reaction can be monitored by conventional monitoring methods in the art (such as HPLC, TLC or LC-MS), and the disappearance or no reaction of the compound 5 is taken as the reaction endpoint. The reaction time can be 1 to 20 hours, such as 1 to 3 hours, and another example is 2 hours.

[0050] In a preferred embodiment, in step S5, after the oxidation reaction is completed, the following post-treatment step is further included, and the post-treatment step is a conventional post-treatment operation for such reactions in the art, for example, including one or more of quenching, concentration and purification. The quenching reagent may be anisole. The purification may be column chromatography, and the eluent of the column chromatography may be dichloromethane and methanol, and the volume ratio of dichloromethane to methanol may be (10-100):1.

[0051] In a preferred embodiment, the preparation method of compound 6 comprises the following steps: adding a solvent to compound 5, cooling (e.g., -5°C), adding an oxidant, stirring at 0-5°C for 1-3h, and after the reaction is completed, post-treating to obtain the compound.

[0052] In a preferred embodiment, the preparation method of compound 6 also includes the preparation method of compound 5, and the preparation method of compound 5 includes the following step S4: in a solvent, compound 4 is subjected to a hydrolysis reaction as shown in the following formula under the action of a base to obtain compound 5,

[0053]

[0054] In a preferred embodiment, in step S4, the solvent is a ketone organic solvent, such as acetone.

[0055] In a preferred embodiment, in step S4, the molar volume ratio of the compound 4 to the solvent is (50-150) mmol:1L, for example (50-133) mmol:1L, and for example 66 mmol:1L.

[0056] In a preferred embodiment, in step S4, the base is selected from one or both of sodium formate and sodium acetate; for example, sodium formate.

[0057] In a preferred embodiment, in step S4, the molar ratio of the base to the compound 4 is (3.5-13.5):1, for example (4-8.5):1, for example (5-8.5):1, and more for example 6:1.

[0058] In a preferred embodiment, in step S4, the temperature of the hydrolysis reaction is 30-50°C, such as 35-45°C, and another example is 40°C.

[0059] In a preferred embodiment, in step S4, the hydrolysis reaction is carried out under light-proof conditions.

[0060] In a preferred embodiment, in step S4, the hydrolysis reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere.

[0061] In a preferred embodiment, the preparation method of compound 5 comprises the following steps: adding a base to compound 4, stirring at 35-45°C for 18-22 hours, and after the reaction is completed, diluting, extracting, concentrating, beating, filtering, and drying to obtain the compound 5.

[0062] In step S4, the progress of the hydrolysis reaction can be detected by conventional monitoring methods for such reactions in the art (e.g., HPLC, TLC, or LC-MS), and the disappearance or no reaction of compound 4 is taken as the end point of the reaction. The hydrolysis reaction time can be 15 to 25 hours, for example, 18 to 22 hours, and for example, 20 hours.

[0063] In a preferred embodiment, in step S4, after the hydrolysis reaction is completed, the following post-processing steps are further included, and the post-processing steps are conventional post-processing steps for such reactions in the art, for example, including one or more of dilution, extraction, drying, concentration, pulping and filtration. The dilution solvent may be water. The extraction solvent may be dichloromethane. The pulping solvent may be methyl tert-butyl ether.

[0064] In a preferred embodiment, the preparation method of compound 5 also includes the preparation method of compound 4, and the preparation method of compound 4 includes the following step S3: in a solvent, compound 3 is subjected to the reaction shown in the following formula under the action of an acid to obtain compound 4,

[0065]

[0066] Among them, each R 1 It is methyl, ethyl, n-propyl, isopropyl, n-butyl or n-pentyl.

[0067] In a preferred embodiment, each R 1 It is methyl.

[0068] In a preferred embodiment, in step S3, the solvent is a ketone organic solvent, such as acetone.

[0069] In a preferred embodiment, in step S3, the molar volume ratio of the compound 3 to the solvent is (50-150) mmol:1L, for example (50-133) mmol:1L, and for example 66 mmol:1L.

[0070] In a preferred embodiment, in step S3, the acid is selected from one or more of hydrogen bromide, hydrochloric acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and trifluoromethanesulfonic acid; for example, hydrogen bromide.

[0071] In a preferred embodiment, in step S3, the hydrogen bromide is added in the form of an aqueous hydrogen bromide solution; the molar concentration of hydrogen bromide in the aqueous hydrogen bromide solution may be 0.15 to 0.3 mol / L, for example 0.15 mol / L.

[0072] In a preferred embodiment, in step S3, the molar ratio of the acid to the compound 3 is (2-4):1, for example 2.3:1 or 3.4:1.

[0073] In a preferred embodiment, in step S3, the reaction temperature is 30-50°C, such as 35-45°C, and another example is 40°C.

[0074] In a preferred embodiment, in step S3, the reaction is carried out under light-proof conditions.

[0075] In a preferred embodiment, in step S3, the reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere.

[0076] In a preferred embodiment, in step S3, after the reaction is completed, the next step of reaction is directly carried out without any post-treatment.

[0077] In a preferred embodiment, the preparation method of compound 4 comprises the following steps: adding a solvent to compound 3, stirring to dissolve, adding an acid, reacting at 35-45°C for 4-6 hours, and directly proceeding to the next step of reaction after TLC detection shows that the conversion is complete without post-treatment.

[0078] In step S3, the progress of the reaction can be monitored by conventional monitoring methods for such reactions in the art (e.g., HPLC, TLC, or LC-MS), and the disappearance or no-reaction of compound 3 is taken as the end point of the reaction. The reaction time of the reaction can be 4 to 6 hours, for example, 4 hours.

[0079] In a preferred embodiment, when the reaction in step S3 is directly carried out to the next step without any post-treatment, in step S4, the amount of the base and the solvent is calculated based on the yield of step S3 being 100%.

[0080] In a preferred embodiment, the preparation method of compound 5 comprises the following steps: adding a solvent to compound 3, stirring to dissolve, adding an acid, reacting at 35-45°C for 4-6 hours, adding a base to the reaction system after TLC detection shows that the conversion is complete, stirring at 35-45°C for 18-22 hours, and after the reaction is completed, diluting, extracting, concentrating, pulping, filtering, and drying to obtain the compound 5.

[0081] In a preferred embodiment, the preparation method of compound 4 also includes the preparation method of compound 3, and the preparation method of compound 3 includes the following step S2: in a solvent, in the presence of a base and a reducing agent, compound A-2 and / or its salt and compound 2s are subjected to a reductive amination reaction as shown in the following formula to obtain compound 3,

[0082]

[0083] Each R 1 The definition of is as described in any embodiment of the present invention.

[0084] In a preferred embodiment, the salt of compound A-2 is selected from One or more of

[0085] In a preferred embodiment, step S2 comprises the following steps: in a solvent, in the presence of a base and a reducing agent, subjecting compound 2 and compound 2s to a reductive amination reaction as shown in the following formula to obtain compound 3:

[0086]

[0087] In a preferred embodiment, in step S2, the solvent is an ether solvent, and the ether solvent can be selected from one or more of ethylene glycol dimethyl ether, 1,4-dioxane and tetrahydrofuran, such as tetrahydrofuran.

[0088] In a preferred embodiment, in step S2, the molar volume ratio of the "compound A-2 and / or its salt" to the solvent is (50-150) mmol:1L, for example (80-100) mmol:1L, and another example is 91 mmol:1L.

[0089] In a preferred embodiment, in step S2, the base is an inorganic base; for example, the inorganic base is selected from one or more of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate and calcium carbonate, tripotassium phosphate, trisodium phosphate, dipotassium hydrogen phosphate and disodium hydrogen phosphate; another example is sodium bicarbonate.

[0090] In a preferred embodiment, in step S2, the molar ratio of the base to the "compound A-2 and / or its salt" is (1-3):1, for example (2.5-3.5):1, and for example 3:1.

[0091] In a preferred embodiment, in step S2, the reducing agent is selected from one or more of sodium borohydride, potassium borohydride, lithium borohydride, sodium cyanoborohydride and lithium aluminum hydride, such as sodium cyanoborohydride.

[0092] In a preferred embodiment, in step S2, the molar ratio of the reducing agent to the "compound A-2 and / or its salt" is (1-5):1, for example (1-3):1, and for example 1.5:1.

[0093] In a preferred embodiment, in step S2, the molar ratio of the compound 2s to the "compound A-2 and / or its salt" is (1-5):1, for example (2-4):1, and for example 3:1.

[0094] In a preferred embodiment, in step S2, the temperature of the reductive amination reaction is 10-25°C, for example 25°C.

[0095] In a preferred embodiment, in step S2, the reductive amination reaction is carried out under light-proof conditions.

[0096] In a preferred embodiment, the preparation method of compound 3 comprises the following steps: adding compound A-2 and / or its salt to a solvent, cooling down (for example, to 0°C), adding a base, stirring for 3 to 8 minutes, adding 2-[(1S)-1-methoxy-2-oxoethoxy]acetaldehyde and a reducing agent, stirring at 10 to 25°C, and after the reaction is completed, post-treating to obtain the product.

[0097] In step S2, the progress of the reaction can be detected by conventional monitoring methods for such reactions in the art (e.g., HPLC, TLC, or LC-MS), and the disappearance or no reaction of compound 2 is taken as the end point of the reaction. The reaction time of the reaction can be 10 to 20 hours, for example, 15 to 20 hours, and for example, 16 hours.

[0098] In a preferred embodiment, in step S2, after the reaction is completed, the following post-processing steps are further included, and the post-processing steps are conventional post-processing steps for such reactions in the art, for example, including one or more of filtration, extraction, washing, drying, concentration and purification. The solvent for the extraction may be methyltetrahydrofuran. The solvent for the washing may be water. The purification is column chromatography, and the eluent for the column chromatography may be dichloromethane and methanol, and the volume ratio of dichloromethane to methanol may be 80:1.

[0099] In a preferred embodiment, when the "compound A-2 and / or its salt" in step S2 is compound 2, the preparation method of compound 3 further includes a preparation method of compound 2, and the preparation method of compound 2 includes the following steps S1: in a solvent, in the presence of a catalyst and an additive, compound 1, Br2 and a reaction reagent are reacted as shown in the following formula to obtain compound 2,

[0100]

[0101] The reaction reagent is R 1OH; each R 1 It is methyl, ethyl, n-propyl, isopropyl, n-butyl or n-pentyl.

[0102] In a preferred embodiment, in step S1, the solvent is an ether solvent; for example, the ether solvent is ethylene glycol dimethyl ether, 1,4-dioxane or tetrahydrofuran, such as 1,4-dioxane.

[0103] In a preferred embodiment, in step S1, the reaction reagent is methanol, ethanol, 1-propanol, 1-butanol or 1-pentanol; for example, methanol.

[0104] In a preferred embodiment, in step S1, the volume ratio of the reaction reagent to the solvent is 1:(0.5-1.5), for example 1:(0.5-1), and for example 1:1.

[0105] In a preferred embodiment, in step S1, the molar volume ratio of the compound 1 to the solvent is (100-300) mmol:1L, for example (200-260) mmol:1L, and for example 236 mmol:1L.

[0106] In a preferred embodiment, in step S1, the additive is trimethyl orthoformate, triethyl orthoformate or triisopropyl orthoformate, for example, trimethyl orthoformate.

[0107] In a preferred embodiment, in step S1, the molar ratio of the additive to the compound 1 is (17-20):1, for example (18-19):1, and for example 18.5:1.

[0108] In a preferred embodiment, in step S1, the catalyst is a sulfonic acid, such as p-toluenesulfonic acid, benzenesulfonic acid, 4-ethylbenzenesulfonic acid, 4-chlorobenzenesulfonic acid, xylenesulfonic acid, 2,3-dimethylbenzenesulfonic acid, 2,4-dimethylbenzenesulfonic acid, 2,5-dimethylbenzenesulfonic acid, 2,6-dimethylbenzenesulfonic acid or methanesulfonic acid, and p-toluenesulfonic acid.

[0109] In a preferred embodiment, in step S1, the molar ratio of the catalyst to the compound 1 is (0.1-0.3):1, for example, 0.1:1.

[0110] In a preferred embodiment, in step S1, the Br2 is added in the form of a dichloromethane solution of Br2, and the volume ratio of dichloromethane to Br2 can be (1-20):1, for example (6-18):1, and for example 16.9:1.

[0111] In a preferred embodiment, in step S1, the molar ratio of Br2 to compound 1 is (1-3):1, for example (1-2):1, and for example 1.3:1.

[0112] In a preferred embodiment, in step S1, the Br2 is added dropwise.

[0113] In a preferred embodiment, step S1 includes the following steps:

[0114] (I) mixing compound 1, a catalyst, a reaction reagent and a solvent to obtain a mixed solution;

[0115] (II) mixing the mixed solution obtained in step (I) with an additive (for example, mixing at 0° C.) to obtain a mixed solution;

[0116] (III) Add Br2 to the mixed solution obtained in step (II) to react and obtain compound 2.

[0117] In a preferred embodiment, in step S1, the reaction temperature is -10 to 10°C, such as -5 to 5°C, and another example is 0°C.

[0118] In a preferred embodiment, in step S1, the reaction is carried out under light-proof conditions.

[0119] In a preferred embodiment, in step S1, the reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere.

[0120] In a preferred embodiment, in step S1, the preparation method of compound 2 comprises the following steps: adding compound 1 and a catalyst to a mixture consisting of a solvent and a reaction reagent, adding an additive after cooling (for example, 0°C) under the protection of an inert gas, adding Br2 dropwise, stirring at -5 to 5°C for 3 to 5 hours, and after the reaction is completed, post-treating to obtain the product.

[0121] In step S1, the progress of the reaction can be detected by conventional monitoring methods for such reactions in the art (e.g., HPLC, TLC, or LC-MS), and the disappearance or no reaction of compound 1 is taken as the end point of the reaction. The reaction time of the reaction can be 3 to 6 hours, for example, 3 to 5 hours, and for example, 4 hours.

[0122] In a preferred embodiment, in step S1, after the reaction is completed, the following post-processing steps are further included, and the post-processing steps are conventional post-processing steps for such reactions in the art, for example, including one or more of quenching, crystallization, filtration, washing and drying. The quenching reagent may be propylene oxide. The crystallization solvent may be methyl tert-butyl ether. The washing solvent may be methyl tert-butyl ether.

[0123] The present invention provides a crystalline form of compound 7, which is a single crystal, belongs to the monoclinic system, has a space group P21, and has unit cell parameters: α=90°,β=92.23(3)°,γ=90°,unit cell volume The number of asymmetric units in the unit cell is Z = 4, and the charge density is 1.516Mg / m 3 ;

[0124]

[0125] The present invention provides a method for preparing ADC, which comprises the following steps:

[0126] (1) Preparation method of compound 7: comprising the following steps S6: in a solvent, in the presence of a catalyst and an organic base, compound 6 undergoes a ring-closing reaction as shown in the following formula to obtain compound 7

[0127]

[0128] The conditions and operations of the preparation method of compound 7 can be as described in any scheme of the present invention;

[0129] (2) using compound 7 as a raw material to prepare the ADC compound;

[0130] The ADC compounds include but are not limited to the following drugs:

[0131] Anti-CD22-NMS249, huXBR1-402-PNU, NAV-001, NBE-002, SOT102, EGFR VEDVsPNU+EDVs40mer, ADC-1, NBE-001, PNU-159682-P1C1TM or SOT107.

[0132] The structural formula of Anti-CD22-NMS249 is as follows, and the synthesis method of its Payload+linker refers to patent WO2009099741A1.

[0133]

[0134] The structural formula of NBE-002 is as follows, and the synthesis method of its Payload+linker refers to patent WO2016102679A1.

[0135]

[0136] 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.

[0137] The reagents and raw materials used in the present invention are commercially available.

[0138] The positive and progressive effects of the present invention are:

[0139] 1) The present invention provides a method for preparing PNU-159682. The inventors found in experiments that the generation of by-products was effectively reduced by selecting a base and regulating the combination of solvents. The technical problem of low yield in the prior art was effectively solved, and the technical problem of being unable to scale up production in the prior art was also solved.

[0140] 2) Furthermore, using daunorubicin hydrochloride as a raw material, a novel intermediate compound 3 was synthesized, and compound 3 was further deprotected and hydrolyzed to obtain the target intermediate, which not only overcomes the defect of high cost in the prior art, but also the reaction conditions designed using these intermediates are mild, safe, high in yield, and easy in post-processing, which provides a guarantee for the subsequent preparation of high-quality drugs, is suitable for laboratory preparation research, and is especially suitable for industrial large-scale production.

[0141] 3) Although the prior art has reported the preparation of compound 2, the prior art has not reported the direct reductive amination reaction using compound 2 as a raw material. This may be because glycoside compounds are generally unstable under acid-base conditions, which is not conducive to the deprotection of ketal. Glycoside fragments in the intermediate compound 3 of the present application as well as The methoxy group in the fragment has poor stability and is easily hydrolyzed. Based on the structural characteristics of this type of compound, the inventors unexpectedly discovered that by controlling the ratio between the substrate and the reaction reagent in the reaction system, as well as the reaction temperature, the stability of both the glycoside and methoxy sites can be solved at the same time, further improving the reaction yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0142] Figure 1 : Crystal structure diagram of the crystalline form of compound 7.

[0143] Figure 2 : Unit cell stacking diagram of the crystalline form of compound 7.

[0144] Figure 3 : Crystal structure diagram of the crystalline form of compound 3-1.

[0145] Figure 4 : Crystal cell stacking diagram of the crystalline form of compound 3-1. DETAILED DESCRIPTION

[0146] 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.

[0147] Unless otherwise stated, the units used in the following specific experimental descriptions represent the following definitions: N: mol / L; V: ml / g.

[0148] Example 1: Preparation of Compound 2-1

[0149]

[0150] Compound 1 (100 g, 177.31 mmol, 1.0 eq) and p-toluenesulfonic acid (3.05 g, 17.73 mmol, 0.1 eq) were dissolved in methanol (750 mL, 7.5 V) and 1,4-dioxane (750 mL, 7.5 V), protected from light, cooled to 0 ° C under nitrogen protection, and trimethyl orthoformate (347.7 g, 3280 mmol, 18.5 eq) was added; dichloromethane (2 00mL) diluted Br2 (liquid bromine 11.8mL, 1.3eq) was added dropwise to the reaction, and the mixture was stirred at 0°C for 4h. After the reaction was completed, propylene oxide (32mL) was added to quench the mixture, and the mixture was stirred at 0°C for 1h. Methyl tert-butyl ether (7.2L) was added to crystallize the mixture, and the mixture was stirred at 0°C for 0.5h. The mixture was filtered, and the filter cake was washed with methyl tert-butyl ether and dried to obtain compound 2-1 (127.44g, 98%, purity 95.6%).

[0151] 1 H NMR (400MHz, DMSO) δ7.88(q,J=7.7Hz,2H),7.62(d,J=7.7Hz,1H),5.45(s,1H),5.27(s,1H),4.8 7(d,J=4.1Hz,1H),4.57(s,1H),4.18(q,J=6.3Hz,1H),4.00(d,J=18.1Hz,5H),3.60(s,1H),3.4 9(d,J=6.2Hz,6H),3.07(d,J=18.6Hz,1H),2.79(d,J=18.7Hz,1H),2.38(d,J=14.9Hz,1H),2.00 (dd,J=14.9,4.9Hz,1H),1.88(t,J=14.0Hz,1H),1.68(d,J=11.8Hz,1H),1.18(d,J=6.4Hz,3H).

[0152] Example 2: Study on the influence of reaction conditions on the reaction in the preparation of compound 2-1

[0153] 2.1: Effect of trimethyl orthoformate CH(OCH3)3 on the reaction in the preparation of compound 2-1

[0154] Referring to the preparation method of Example 1, the amount of trimethyl orthoformate was changed to investigate its effect on the reaction effect. The IPC purity of the raw material and the product in the reaction solution after 4 hours and 6 hours of reaction was tested by HPLC, and the results are shown in Table 1.

[0155] Table 1

[0156]

[0157] From the results in Table 1, it can be seen that as the amount of CH(OCH3)3 decreases, the corresponding reaction is slower, the reaction is more complicated, and the raw materials cannot be completely converted; as the amount increases, the purity decreases; 18.5eq is the optimal value, the raw materials are completely converted, but the purity decreases as the reaction time continues to increase.

[0158] 2.2: Study on the effect of p-toluenesulfonic acid TsOH on the reaction in the preparation of compound 2-1

[0159] Referring to the preparation method of Example 1, the amount of p-toluenesulfonic acid TsOH was changed to investigate its effect on the reaction effect. The IPC purity of the raw material and the product in the reaction solution after 3 hours, 4 hours and 6 hours of reaction was tested by HPLC, and the results are shown in Table 2.

[0160] Table 2

[0161]

[0162]

[0163] From the results in Table 2, it can be seen that the reaction speed becomes faster when TsOH is added, but the product will decompose when the reaction time is prolonged. When 0.1eq of p-toluenesulfonic acid is used and the reaction time is 4h, the reaction effect is the best.

[0164] 2.3: Study on the effect of reaction temperature on the reaction in the preparation of compound 2-1

[0165] Referring to the preparation method of Example 1, the reaction temperature was changed to examine its effect on the reaction effect. The IPC purity of the raw material and the product in the reaction solution after 5 hours of reaction was tested by HPLC. The results are shown in Table 3.

[0166] Table 3

[0167]

[0168] From the results in Table 3, we can see that at -15-5°C, the temperature is too low and the product purity is very low. At 10-20°C, the reaction proceeds very quickly and the stability becomes poor. The temperature of -5-5°C gives the best results.

[0169] Example 3: Preparation of Compound 3-1

[0170]

[0171] Compound 2-1 (100 g, 136.35 mmol, 1 eq) was added to tetrahydrofuran (1.5 L), protected from light, cooled to 0 ° C, added with sodium bicarbonate (34.36 g, 409.05 mmol, 3.0 eq), stirred for 5 min, and then 2-[(1S)-1-methoxy-2-oxoethoxy]acetaldehyde (54.04 g, 409.05 mmol, 3.0 eq) and sodium cyanoborohydride (12.85 g, 204. 53mmol, 1.5eq), after adding, stir at 0℃ for 1h, stir at 25℃ for 16h. After the reaction is completed, filter, add methyltetrahydrofuran (1L) for extraction, separate the liquids, extract the aqueous phase with methyltetrahydrofuran (500mL×2), combine the organic phases, wash with water (1L), dry the organic phase and concentrate, and purify by column (DCM:MeOH=80:1) to obtain compound 3-1 (98.51g, yield 96%, purity 95.9%).

[0172] 1 H NMR (400MHz, DMSO) δ13.91(d,J=5.7Hz,1H),13.14(d,J=6.5Hz,1H),7.87–7.79(m,1H),7.76(t,J=7.4Hz,1H),7.55(t,J=6.6Hz,1H),5.28(d ,J=2.4Hz,1H),4.89(s,1H),,4.36(d,J=3.0Hz,1H),4.09(t,J=8.7Hz,1H),4.04–3.98(m,3H),3.93(s,3H),3.87–3.79(m,1H),3.78–3.69(m, 2H),3.62–3.52(m,2H),3.50(d,J=2.1Hz,3H),3.49(s,3H),3.45–3.37(m,1H),3.24(d,J=7.2Hz,3H),3.03(d,J=18.8Hz,1H),2.77(d,J=18. 7Hz,1H),2.61(d,J=9.6Hz,1H),2.45(s,1H),2.39(d,J=12.6Hz,2H),2.25(dd,J=11.0,5.4Hz,1H),1.86–1.77(m,2H),1.13(t,J=4.6Hz,3H).

[0173] Example 4: Study on the influence of different solvents on the reaction in the preparation of compound 3-1

[0174] Referring to the preparation method of Example 3, the solvent was changed to investigate its effect on the reaction effect. The IPC purity of the raw material and the product in the reaction solution after 16 hours of reaction was tested by HPLC. The results are shown in Table 4.

[0175] Table 4

[0176]

[0177] From the results in Table 4, it can be seen that THF has the best reaction effect as the reaction solvent.

[0178] Example 5: Preparation of Compounds 4 and 5

[0179]

[0180] Compound 3-1 (100 g, 132.87 mmol, 1.0 eq) was dissolved in acetone (2 L), added to aqueous hydrogen bromide solution (0.15 mol / L, 2 L), protected from light, heated to 40 ° C under nitrogen protection, and stirred for 4 hours before the reaction was complete; sodium formate (54.22 g, 797.23 mmol, 6 eq) was added and stirred at 40 ° C for 20 hours. After the reaction was completed, the reaction solution was diluted with water (3 L), extracted with DCM (5 L), and the aqueous phase was extracted with DCM (2 L × 3). The organic phases were combined, dried and concentrated, slurried with methyl tert-butyl ether (1 L), filtered, and dried to obtain compound 5 (81.25 g, yield 95%, purity 92%).

[0181] 1 H NMR (400MHz, CDCl3) δ13.94(s,1H),13.21(s,1H),8.01(d,J=7.1Hz,1H),7.78(t,J=8.1Hz,1H),7.39(d,J=8.2Hz,1H),5.55(s ,1H),5.37–5.19(m,1H),4.73(d,J=8.9Hz,3H),4.57–4.42(m,1H),4.08(s,3H),4.02–3.85(m,2H),3.74(t,J=6.6Hz,1H),3.68 (s,1H),3.54(dt,J=8.2,3.8Hz,1H),3.39(d,J=7.1Hz,3H),3.24(dd,J=18.8,1.6Hz,1H),3.00(t,J=13.1Hz,3H),2.60(dd,J=1 1.3,4.0Hz,1H),2.54–2.41(m,3H),2.42–2.28(m,2H),2.15(dd,J=14.7,3.9Hz,1H),1.91–1.82(m,1H),1.37(d,J=6.6Hz,3H).

[0182] Example 6: Study on the influence of different conditions on the reaction in the preparation of compounds 4 and 5

[0183] 6.1: Study on the effect of reaction temperature on the deketalization reaction in the preparation of compound 4

[0184] Referring to the preparation method of Example 5 (i.e., compound 3-1 to compound 4), the reaction temperature was changed to examine its effect on the reaction effect. The IPC purity of the raw material and product in the reaction solution after 2 hours, 4 hours and 6 hours of reaction was tested by HPLC, and the results are shown in Table 5.

[0185] Table 5

[0186]

[0187] From the results in Table 5, it can be seen that the lower the temperature, the slower the reaction. The fastest reaction is at 40°C, and the raw material is completely converted in 4 hours. Prolonging the reaction time reduces the purity and significantly increases the impurities.

[0188] 6.2: Study on the influence of deprotection reagent on deketalization reaction in the preparation of compound 4

[0189] Referring to the preparation method of Example 5 (i.e., compound 3-1 to compound 4), the amount of deprotection reagent hydrobromic acid was changed to investigate its effect on the reaction effect. The IPC purity of the raw material and the product in the reaction solution after 4 hours and 6 hours of reaction was tested by HPLC, and the results are shown in Table 6.

[0190] Table 6

[0191]

[0192]

[0193] From the results in Table 6, it can be seen that acid is a deketalization catalyst, but it will affect the stability of the substrate. It can be seen that with less acid, the reaction conversion is slower; with the same amount of acid, the reaction time is extended and the reaction is more complicated (side reactions such as deglycosidation); with too much acid, the side reactions increase and the purity decreases.

[0194] 6.3: Study on the influence of reaction conditions on the reaction in the preparation of compound 5

[0195] Referring to the preparation method of Example 5 (i.e., compound 3-1 to compound 5), the reaction volume was changed to investigate its effect on the reaction effect. The IPC purity of the product in the reaction solution after the reaction was completed was tested by HPLC, and the results are shown in Table 7.

[0196] Table 7

[0197]

[0198] From the results in Table 7, it can be seen that the reaction volume has an impact on the control of reaction impurities.

[0199] 6.4: Study on the effect of sodium formate equivalent on the reaction in the preparation of compound 5

[0200] Referring to the preparation method of Example 5 (i.e., compound 4 to compound 5), the amount of sodium formate was changed to investigate its effect on the reaction effect. The IPC purity of the product in the reaction solution after the reaction was completed was tested by HPLC, and the results are shown in Table 8.

[0201] Table 8

[0202]

[0203] Example 7: Preparation of Compound 6

[0204]

[0205] Compound 5 (100 g, 155.37 mmol, 1.0 eq) was added to DCM (10 L, 100 V), protected from light, cooled to -5°C, m-chloroperbenzoic acid (m-CPBA) (32.17 g, 186.44 mmol, 1.2 eq) was added, the temperature was raised to 0°C, and the mixture was stirred for 2 h. The reaction was monitored by TLC / LCMS / HPLC. After the reaction was complete, thioanisole (4 mL, 0.2 eq) was added and stirred for 1 h to quench the reaction. The mixture was concentrated and purified by column chromatography (DCM:MEOH=100:1-10:1) to obtain compound 6 (91.21 g, yield 89%, purity 95%).

[0206] 1H NMR (400MHz, CDCl3) δ13.87(d,J=5.9Hz,1H),13.09(s,1H),7.89(d,J=7.4Hz,1H),7.70(t,J=8.1Hz,1H),7.30(t,J=8.8Hz,1H),5.61(d,J= 3.2Hz,1H),5.21(d,J=1.8Hz,1H),4.77(d,J=3.6Hz,1H),4.67(s,2H),4.62(d,J=11.3Hz,1H),4.18(s,2H),4.00(s,3H),3.87(dd,J=13.0,6 .4Hz,1H),3.75(d,J=12.6Hz,1H),3.51(t,J=14.5Hz,2H),3.42–3.35(m,3H),3.24(ddd,J=37.4,19.0,12.4Hz,5H),3.09–2.98(m,1H),2.9 2(t,J=17.7Hz,1H),2.77(td,J=12.8,4.0Hz,1H),2.33(d,J=14.8Hz,1H),2.15–2.04(m,1H),1.93(d,J=9.6Hz,1H),1.29(t,J=12.2Hz,3H).

[0207] Example 8: Preparation of Compound 7

[0208]

[0209] Under the protection of inert gas (nitrogen), compound 6 (10 g, 15.2 mmol, 1.0 eq) and a mixture of acetonitrile / tetrahydrofuran (1.5 L / 0.9 L) were added to a reaction bottle, the temperature was controlled to 15 ° C, and protected from light. N, N-diisopropylethylamine (5.9 g, 45.6 mmol, 3.00 eq) was added and stirred to dissolve. Then, cyanuric chloride (4.2 g, 22.8 mmol, 1.5 eq) was added, the temperature was controlled to 15 ° C for 2 h, and after the reaction was complete, , add 3-amino-1,2-propanediol aqueous solution (0.2 L, 0.45 mol / L) and stir for 10 min, then add water (1.8 L) and dichloromethane (1.8 L) and stir for 10 min. After the insoluble matter is precipitated, filter it with diatomaceous earth, wash the organic phase twice with saturated brine, dry it with anhydrous sodium sulfate, filter and concentrate it, and perform column chromatography (DCM / MeOH=500:1~120:1) to obtain compound 7 (6 g, yield 62%, purity 95%).

[0210] 1H NMR (400MHz, CDCl3) δ13.86(s,1H),13.20(s,1H),8.02(d,J=7.6Hz,1H),7.80(t,J=8.1Hz,1H),7.42(d,J=8.4Hz,1H),5.50(t,J=5.4Hz,1H),5 .31(s,1H),4.86(d,J=16.3Hz,1H),4.79(s,2H),4.74(s,1H),4.50(s, 1H),4.11(s,4H),4.07–4.00(m,1H),3.95(t,J=9.3Hz,1H),3.61(d,J=1 1.7Hz,1H),3.49(s,3H),3.42(dd,J=12.3,6.1Hz,1H),3.24(d,J=18.8Hz,1H),3.09(s,1H),3.01(t,J=14.4Hz,1H),2.80(dt,J=17.9,10.3Hz, 2H), 2.53(d,J=14.7Hz,1H), 2.14(dd,J=14.6,3.5Hz,1H), 2.04(dd,J=10.1,4.7Hz,1H), 1.77(dt,J=15.0,6.0Hz,1H), 1.41(t,J=12.5Hz,3H).

[0211] Example 9: Study on the influence of reaction conditions on the reaction in the preparation of compound 7

[0212] 9.1: Study on the effect of base on the reaction in the preparation of compound 7

[0213] Referring to the preparation method of Example 8, the type of base was changed to investigate its effect on the reaction effect. The IPC purity of the product in the reaction solution after 1 hour and 3 hours of reaction was tested by HPLC, and the results are shown in Table 9.

[0214] Table 9

[0215]

[0216] 9.2: Study on the effect of solvent on the reaction in the preparation of compound 7

[0217] Referring to the preparation method of Example 8, the type of solvent was changed to investigate its effect on the reaction effect. The IPC purity of the product in the reaction solution after the reaction was completed was tested by HPLC, and the results are shown in Table 10.

[0218] Table 10

[0219]

[0220]

[0221] Example 10: Preparation of single crystal of compound 7 (3 molecules of chloroform solvate)

[0222] 5 mg of the compound 7 prepared in Example 8 was completely dissolved in 30 μL of chloroform and allowed to stand to cool to obtain.

[0223] Single crystal detection method of compound 7: using Bruker D8 VENTURE (liquid metal target) single crystal X-ray diffractometer, PHOTON III charge integrating pixel array detector, 250W anode liquid gallium target X-ray generator, GaKα radiation, wavelength The distance between the crystal and the detector is d=37mm, the tube voltage is 69.7kV, the tube current is 2.855mA, and the number of independent diffraction points is 12210.

[0224] The crystal structure of the crystalline form of compound 7 is shown in Figure 1 As shown; the unit cell stacking diagram of the crystalline form of compound 7 is as shown Figure 2 shown.

[0225] The crystallographic parameters of the crystalline form of compound 7 are shown in Table 11.

[0226] Table 11

[0227]

[0228] Example 11: Preparation method of the crystalline form of compound 3-1.

[0229] Single crystal cultivation: 5 mg of the compound 3-1 prepared in Example 3 was weighed and dissolved in 0.5 mL of acetonitrile, and liquid-phase diffused with 1.5 mL of water to obtain a crystalline sample.

[0230] Single crystal detection method of compound 3-1: using Bruker D8 VENTURE double micro-focus single crystal X-ray diffractometer, PHOTON III charge integrating pixel array detector, CuKα radiation, wavelength The distance between the crystal and the detector is d = 40 mm, the tube voltage is 50.0 kV, the tube current is 1.100 mA, and the number of independent diffraction points is 39319.

[0231] The crystal structure of the crystalline form of compound 3-1 is shown in Figure 3 The crystal cell stacking diagram of the crystalline form of compound 3-1 is shown in Figure 4 shown.

[0232] The crystallographic parameters of the crystalline form of compound 3-1 are shown in Table 12.

[0233] Table 12

[0234]

[0235]

Claims

1. A method for preparing compound 7, characterized in that: The preparation method of the compound 7 comprises the following step S6: in a solvent, in the presence of a catalyst and an organic base, subjecting the compound 6 to a ring-closing reaction as shown in the following formula to obtain the compound 7, The organic base is 2,6-diisopropylaniline and / or N,N-diisopropylethylamine; The solvent is a mixed solvent consisting of a nitrile solvent and an ether solvent.

2. The method for preparing compound 7 according to claim 1, characterized in that: The preparation method of compound 7 satisfies one or more of the following conditions: (1) In step S6, the nitrile solvent is acetonitrile; (2) In step S6, the ether solvent is one or more of tetrahydrofuran, dioxane and ethylene glycol dimethyl ether, such as tetrahydrofuran; (3) In step S6, the volume ratio of the ether solvent to the nitrile solvent is (0.2-1):1; for example (0.5-0.7):1, and for example 0.6:1; (4) In step S6, the molar volume ratio of the compound 6 to the solvent is 1 mmol:(0.1-0.3) L, for example, 1 mmol:(0.1-0.2) L, and for example, 1 mmol:0.16 L; (5) In step S6, the organic base is N,N-diisopropylethylamine; (6) In step S6, the molar ratio of the organic base to the compound 6 is (1-5):1, for example (1.5-3.5):1, and for example 3:1; (7) In step S6, the catalyst is a triazine compound, such as cyanuric chloride; (8) In step S6, the molar ratio of the catalyst to the compound 6 is (1-3):1, for example (1-2):1, and for example 1.5:1; (9) In step S6, the temperature of the ring-closure reaction is 5 to 25° C., for example, 10 to 18° C., and for example, 15° C.; (10) In step S6, the reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere; (11) In step S6, the ring-closure reaction is carried out in a light-proof condition; (12) In step S6, the reaction time is 2 to 7 hours, for example 2 to 5 hours, and for example 2 hours; and (13) In step S6, after the ring-closure reaction is completed, the following post-treatment steps are further included: one or more of quenching, extraction, filtration, washing, drying, concentration and purification; the quenching reagent can be an aqueous solution of 3-amino-1,2-propanediol; the extraction solvent can be dichloromethane; the washing solution can be saturated brine; the drying desiccant can be anhydrous sodium sulfate; the purification can be column chromatography, and the eluent of the column chromatography can be dichloromethane and methanol, and the volume ratio of dichloromethane to methanol can be (120-500):

1.

3. The method for preparing compound 7 according to claim 1, characterized in that: The preparation method of the compound 7 also includes the preparation method of the compound 6, and the preparation method of the compound 6 includes the following step S5: in a solvent, in the presence of an oxidant, subjecting the compound 5 to an oxidation reaction as shown in the following formula to obtain the compound 6, Preferably, the preparation method of compound 6 satisfies one or more of the following conditions: (1) In step S5, the solvent is a chlorinated alkane organic solvent, such as one or more of dichloromethane, 1,2-dichloroethane and chloroform, and another example is dichloromethane; (2) In step S5, the molar volume of the compound 5 and the solvent is (1-30) mmol:1 L, for example (10-20) mmol:1 L, and for example 15.6 mmol:1 L; (3) In step S5, the oxidant is selected from one or more of Jones reagent, Collins reagent, pyridinium chlorochromate, pyridinium dichromate, manganese dioxide, Dess-Martin periodinane, potassium permanganate, periodic acid, osmium tetroxide, 30% hydrogen peroxide, meta-chloroperbenzoic acid and tert-butyl hydroperoxide; for example, meta-chloroperbenzoic acid; (4) In step S5, the molar ratio of the oxidant to the compound 5 is (1-3):1, for example (1-2):1, and for example 1.2:1; (5) In step S5, the oxidant is added at a temperature of -10 to 0°C, for example, at -5°C; (6) In step S5, the oxidation reaction is carried out under light-proof conditions; (7) In step S5, the temperature of the oxidation reaction is -20 to 25°C, for example, 0 to 5°C, and for example, 0°C; (8) In step S5, the reaction time is 1 to 20 hours, for example 1 to 3 hours, and for example 2 hours; and (9) In step S5, after the oxidation reaction is completed, the following post-treatment steps are further included: one or more of quenching, concentration and purification; the quenching reagent can be anisole; the purification can be column chromatography, and the eluent of the column chromatography can be dichloromethane and methanol, and the volume ratio of dichloromethane to methanol can be (10-100):

1.

4. The method for preparing compound 7 according to claim 3, characterized in that: The preparation method of the compound 6 also includes the preparation method of the compound 5, and the preparation method of the compound 5 includes the following step S4: in a solvent, subjecting the compound 4 to a hydrolysis reaction as shown in the following formula under the action of a base to obtain the compound 5, Preferably, the preparation method of compound 5 satisfies one or more of the following conditions: (1) In step S4, the solvent is a ketone organic solvent, such as acetone; (2) In step S4, the molar volume ratio of the compound 4 to the solvent is (50-150) mmol:1 L, for example (50-133) mmol:1 L, and for example 66 mmol:1 L; (3) In step S4, the base is selected from one or both of sodium formate and sodium acetate; for example, sodium formate; (4) In step S4, the molar ratio of the base to the compound 4 is (3.5-13.5):1, for example (4-8.5):1, for example (5-8.5):1, and more preferably 6:1; (5) In step S4, the temperature of the hydrolysis reaction is 30 to 50° C., for example, 35 to 45° C., and for example, 40° C.; (6) In step S4, the hydrolysis reaction is carried out under light-proof conditions; (7) In step S4, the hydrolysis reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere; (8) In step S4, the hydrolysis reaction time is 15 to 25 hours, for example 18 to 22 hours, and for example 20 hours; (9) In step S4, after the hydrolysis reaction is completed, the following post-treatment steps are also included: one or more of dilution, extraction, drying, concentration, pulping and filtration; the dilution solvent may be water; the extraction solvent may be dichloromethane; the pulping solvent may be methyl tert-butyl ether.

5. The method for preparing compound 7 according to claim 4, characterized in that: The preparation method of the compound 5 also includes the preparation method of the compound 4, and the preparation method of the compound 4 includes the following step S3: in a solvent, compound 3 is subjected to a reaction shown in the following formula under the action of an acid to obtain compound 4, Among them, each R 1 is methyl, ethyl, n-propyl, isopropyl, n-butyl or n-pentyl; Preferably, the preparation method of compound 4 satisfies one or more of the following conditions: (1) Each R 1 is methyl; (2) In step S3, the solvent is a ketone organic solvent, such as acetone; (3) In step S3, the molar volume ratio of the compound 3 to the solvent is (50-150) mmol:1 L, for example (50-133) mmol:1 L, and for example 66 mmol:1 L; (4) In step S3, the acid is selected from one or more of hydrogen bromide, hydrochloric acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and trifluoromethanesulfonic acid; for example, hydrogen bromide; preferably, the hydrogen bromide is added in the form of an aqueous hydrogen bromide solution; the molar concentration of hydrogen bromide in the aqueous hydrogen bromide solution may be 0.15 to 0.3 mol / L, for example, 0.15 mol / L; (5) In step S3, the molar ratio of the acid to the compound 3 is (2-4):1, for example 2.3:1 or 3.4:1; (6) In step S3, the reaction temperature is 30 to 50° C., for example, 35 to 45° C., and for example, 40° C.; (7) In step S3, the reaction is carried out under light-proof conditions; (8) In step S3, the reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere; (9) in step S3, after the reaction is completed, the next step of reaction is directly carried out without any post-treatment; and (10) In step S3, the reaction time is 4 to 6 hours, for example 4 hours.

6. The method for preparing compound 7 according to claim 5, characterized in that: The preparation method of the compound 4 further includes a preparation method of the compound 3, and the preparation method of the compound 3 includes the following step S2: in a solvent, in the presence of a base and a reducing agent, subjecting the compound A-2 and / or its salt to a reductive amination reaction with the compound 2s as shown in the following formula to obtain the compound 3, Each R 1 is methyl, ethyl, n-propyl, isopropyl, n-butyl or n-pentyl; Preferably, the preparation method of compound 3 satisfies one or more of the following conditions: (1) The salt of compound A-2 is selected from One or more of (2) In step S2, the solvent is an ether solvent, and the ether solvent can be selected from one or more of ethylene glycol dimethyl ether, 1,4-dioxane and tetrahydrofuran, such as tetrahydrofuran; (3) In step S2, the molar volume ratio of the "compound A-2 and / or its salt" to the solvent is (50-150) mmol:1 L, for example (80-100) mmol:1 L, and for example 91 mmol:1 L; (4) In step S2, the base is an inorganic base; for example, the inorganic base is selected from one or more of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate and calcium carbonate, tripotassium phosphate, trisodium phosphate, dipotassium hydrogen phosphate and disodium hydrogen phosphate; another example is sodium bicarbonate; (5) In step S2, the molar ratio of the base to the "compound A-2 and / or its salt" is (1-3):1, for example (2.5-3.5):1, and for example 3:1; (6) In step S2, the reducing agent is selected from one or more of sodium borohydride, potassium borohydride, lithium borohydride, sodium cyanoborohydride and lithium aluminum hydride, such as sodium cyanoborohydride; (7) In step S2, the molar ratio of the reducing agent to the "compound A-2 and / or its salt" is (1-5):1, for example (1-3):1, and for example 1.5:1; (8) In step S2, the molar ratio of the compound 2s to the "compound A-2 and / or its salt" is (1-5):1, for example (2-4):1, and for example 3:1; (9) In step S2, the temperature of the reductive amination reaction is 10 to 25° C., for example, 25° C.; (10) In step S2, the reductive amination reaction is carried out under light-proof conditions; (11) In step S2, the reaction time is 10 to 20 hours, for example 15 to 20 hours, and for example 16 hours; (12) In step S2, after the reaction is completed, the following post-treatment steps are further included: one or more of filtration, extraction, washing, drying, concentration and purification; the extraction solvent may be methyltetrahydrofuran; the washing solvent may be water; the purification is column chromatography, the eluent of the column chromatography may be dichloromethane and methanol, and the volume ratio of dichloromethane to methanol may be 80:1; and (13) Each R 1 It is methyl.

7. The method for preparing compound 7 according to claim 6, characterized in that: The step S2 comprises the following steps: in a solvent, in the presence of a base and a reducing agent, subjecting compound 2 and compound 2s to a reductive amination reaction as shown in the following formula to obtain compound 3:

8. The method for preparing compound 7 according to claim 7, characterized in that: The preparation method of the compound 3 also includes the preparation method of the compound 2, and the preparation method of the compound 2 includes the following steps S1: in a solvent, in the presence of a catalyst and an additive, compound 1, Br2 and a reaction reagent are reacted as shown in the following formula to obtain compound 2, The reaction reagent is R 1 OH; each R 1 is methyl, ethyl, n-propyl, isopropyl, n-butyl or n-pentyl; Preferably, the preparation method of compound 2 satisfies one or more of the following conditions: (1) Each R 1 is methyl; (2) In step S1, the solvent is an ether solvent; for example, the ether solvent is ethylene glycol dimethyl ether, 1,4-dioxane or tetrahydrofuran, and another example is 1,4-dioxane; (3) In step S1, the volume ratio of the reaction reagent to the solvent is 1:(0.5-1.5), for example 1:(0.5-1), and for example 1:1; (4) In step S1, the molar volume ratio of the compound 1 to the solvent is (100-300) mmol:1 L, for example (200-260) mmol:1 L, and for example 236 mmol:1 L; (5) In step S1, the additive is trimethyl orthoformate, triethyl orthoformate or triisopropyl orthoformate, for example, trimethyl orthoformate; (6) In step S1, the molar ratio of the additive to the compound 1 is (17-20):1, for example (18-19):1, and for example 18.5:1; (7) In step S1, the catalyst is a sulfonic acid, such as p-toluenesulfonic acid, benzenesulfonic acid, 4-ethylbenzenesulfonic acid, 4-chlorobenzenesulfonic acid, xylenesulfonic acid, 2,3-dimethylbenzenesulfonic acid, 2,4-dimethylbenzenesulfonic acid, 2,5-dimethylbenzenesulfonic acid, 2,6-dimethylbenzenesulfonic acid or methanesulfonic acid, and p-toluenesulfonic acid; (8) In step S1, the molar ratio of the catalyst to the compound 1 is (0.1-0.3):1, for example 0.1:1; (9) In step S1, the Br2 is added in the form of a dichloromethane solution of Br2, and the volume ratio of dichloromethane to Br2 can be (1-20):1, for example (6-18):1, and another example is 16.9:1; (10) In step S1, the molar ratio of Br2 to compound 1 is (1-3):1, for example (1-2):1, and for example 1.3:1; (11) In step S1, the Br2 is added dropwise; (12) In step S1, the reaction temperature is -10 to 10°C, for example -5 to 5°C, and for example 0°C; (13) In step S1, the reaction is carried out under light-proof conditions; (14) In step S1, the reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere; (15) In step S1, the reaction time of the reaction may be 3 to 6 hours, for example 3 to 5 hours, and for example 4 hours; (16) In step S1, it includes the following steps: (I) mixing compound 1, a catalyst, a reaction reagent and a solvent to obtain a mixed solution; (II) mixing the mixed solution obtained in step (I) with an additive; A mixed solution is obtained; (III) adding Br2 to the mixed solution obtained in step (II) to react to obtain compound 2; and (17) In step S1, after the reaction is completed, the following post-treatment steps are further included: one or more of quenching, crystallization, filtration, washing and drying; the quenching reagent may be propylene oxide; the crystallization solvent may be methyl tert-butyl ether; the washing solvent may be methyl tert-butyl ether.

9. A crystalline form of compound 7, characterized in that: It is a single crystal, belongs to the monoclinic system, space group P21, unit cell parameters: α=90°,β=92.23(3)°,γ=90°,unit cell volume The number of asymmetric units in the unit cell is Z = 4, and the charge density is 1.516Mg / m 3 ; 10. A method for preparing ADC, characterized in that: It includes the following steps: (1) Preparation method of compound 7: The method comprises the following steps S6: in a solvent, in the presence of a catalyst and an organic base, compound 6 undergoes a ring-closing reaction as shown in the following formula to obtain compound 7; The conditions and operations of the preparation method of compound 7 may be as described in any one of claims 1 to 8; (2) using compound 7 as a raw material to prepare the ADC compound; The ADC compounds include the following drugs: Anti-CD22-NMS249, huXBR1-402-PNU, NAV-001, NBE-002, SOT102, EGFR VEDVsPNU+EDVs40 mer, ADC-1, NBE-001, PNU-159682-P1C1TM or SOT107.

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