Preparation method of a linker-drug conjugate and intermediate thereof

Abstract

The present invention discloses a preparation method of a linker-drug conjugate and an intermediate thereof, and specifically discloses a preparation method of a compound of formula I, which comprises the following steps: removing the R of the compound of formula II 4 protecting group to obtain the compound of formula I; wherein, R 1 is C 1 ~C 6 alkyl, one or more R 1‑3 S(O) 2 -substituted C 1 ~C 6 alkyl, or one or more N(R 1‑1 )(R 1 - 2 )-substituted C 1 ~C 6 alkyl; R 2 and R 3 are each independently C 1 ~C 6 alkyl, one or more halogen-substituted C 1 ~C 6 alkyl, or halogen; R 1‑1 , R 1‑2 and R 1‑3 are each independently C 1 ~C 4 alkyl; R 4 is a hydroxyl protecting group. The preparation method of the present invention has one or more of the following advantages: simple operation, high yield, effectively avoiding the generation of special by-products, easy to control the product quality and suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the field of drug synthesis, and particularly relates to a preparation method of a linker-drug conjugate and an intermediate thereof. Background Art

[0002] Antibody-drug conjugates (ADCs) have been one of the hotspots in the pharmaceutical industry in recent years. Since the curative effects of many antibody drugs in clinical practice are not satisfactory, many industry giants have increasingly turned their attention to ADC drugs. The basic modules of ADC drugs include antibodies, linkers, and effector molecules. The antibodies are used to transport the effector molecules to accumulate at the tumor site, thereby killing tumor cells. Traditional effector molecules are mostly highly active tubulin inhibitors, usually with large toxic and side effects, which limit the application of ADCs. Recently, Immunomedics has invented a new type of ADC drug IMMU-132 (ZL200980156218) with a camptothecin compound as the effector molecule, which has shown good anti-tumor effects. Daiichi Sankyo has invented another ADC drug DS-8201a (ZL201380053256) with a camptothecin compound as the effector molecule, which also shows good anti-tumor effects.

[0003] WO2020259258A1 discloses an ADC compound with a camptothecin derivative Dxd as the effector molecule, and such compounds also show good anti-tumor effects. Among them, the target ADC compound can be obtained by conjugating the camptothecin derivative shown in Formula I with an antibody, and the linker-drug conjugate shown in Formula I can be prepared by the following Synthetic Route 1 or Synthetic Route 2.

[0004] Route 1:

[0005]

[0006] The synthesis method of Route 1 includes: reacting Compound 1-1 with 4-aminobenzyl alcohol, reacting the obtained compound with bis(p-nitrophenyl) carbonate and then with a substituted alkylamine to obtain Compound 1-2, reacting Compound 1-2 with paraformaldehyde and trimethylchlorosilane to obtain Compound 1-3, reacting Compound 1-3 with tert-butyl glycolate and then removing the tert-butyl group under the action of trifluoroacetic acid to obtain Compound 1-4, reacting Compound 1-4 with irinotecan mesylate to obtain Compound 1-5, removing the Fmoc protection on the amino group under the action of DBU and then coupling with N-succinimidyl 6-(maleimidocaproate) to obtain the target compound I.

[0007] Route 2:

[0008]

[0009] The synthesis method of Route 2 includes: reacting compound 2-1 with paraformaldehyde and trimethylchlorosilane, reacting the obtained compound with tert-butyl glycolate to obtain compound 2-2, removing the tert-butyl group from compound 2-2 under the action of trifluoroacetic acid and then reacting with irinotecan mesylate to obtain compound 2-3, reducing the azide to an amino group under the action of triethylphosphine in compound 2-3 to obtain compound 2-4, and carrying out a coupling reaction between compound 2-4 and MC-V to obtain the target compound I.

[0010] However, the synthesis methods of the above Route 1 and Route 2 have the problem that the purity of the final product is unqualified during the actual production scale-up process. Therefore, it is necessary to explore a new route to make the purity of the final product meet the requirements. Summary of the Invention

[0011] The technical problem to be solved by the present invention is that it is difficult to obtain a final product with qualified purity by the existing preparation methods of the linker drug conjugate shown in Formula I. Therefore, the present invention provides a new preparation method of the linker drug conjugate shown in Formula I and its intermediates. The preparation method of the present invention has one or more of the following advantages: simple operation, high yield, effectively avoiding the generation of special by-products, easy to control the product quality and suitable for industrial production.

[0012] The present invention provides a preparation method of a compound of Formula I, which includes the following steps: removing the R 4 protecting group to obtain the compound of Formula I;

[0013]

[0014] wherein, R 1 is C 1 ~C 6 alkyl, one or more R 1-3 S(O) 2 -substituted C 1 ~C 6 alkyl, or one or more N(R 1-1 )(R 1-2 )-substituted C 1 ~C 6 alkyl;

[0015] R 2 and R 3 each independently is C 1 ~C 6 alkyl, one or more halogen-substituted C 1 ~C 6 alkyl, or halogen;

[0016] R 1-1 、R 1-2 and R 1-3 each independently is C1 ~C 4 alkyl;

[0017] R 4 is a hydroxyl protecting group.

[0018] In some embodiments, in the definitions of R 1 , R 2 and R 3 , the C 1 ~C 6 alkyl can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl or ethyl.

[0019] In some embodiments, in the definitions of R 2 and R 3 , the halogen can be fluorine, chlorine, bromine or iodine, preferably fluorine.

[0020] In some embodiments, in the definitions of R 1-1 , R 1-2 and R 1-3 , the C 1 ~C 4 alkyl can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl.

[0021] In some embodiments, R 1 is an R 1-3 S(O) 2 -substituted C 1 ~C 6 alkyl or an -NR 1-1 R 1-2 -substituted C 1 ~C 6 alkyl, preferably methylsulfonylethyl or N,N-dimethylethyl, more preferably methylsulfonylethyl.

[0022] In some embodiments, R 2 is C 1 ~C 6 alkyl, preferably methyl.

[0023] In some embodiments, R 3 is halogen, preferably fluorine or chlorine, more preferably fluorine.

[0024] In some embodiments, R 1 is an R 1-3 S(O) 2 -substituted C 1 ~C 6 alkyl, such as methylsulfonylethyl;

[0025] R2 is C 1 ~C 6 alkyl, such as methyl;

[0026] R 3 is halogen, such as fluorine;

[0027] R 1-3 is C 1 ~C 4 alkyl, such as methyl.

[0028] In some embodiments, R 1 is defined as described in any of the foregoing embodiments, R 2 is methyl, and R 3 is fluorine.

[0029] In some embodiments, R 1 is methylsulfonylethyl, R 2 is methyl, and R 3 is fluorine.

[0030] In some embodiments, in the definition of R 4 , the hydroxyl protecting group is a conventional hydroxyl protecting group in the art, such as an ester protecting group (i.e., R 4 is acyl) or a silyl ether protecting group (i.e., R 4 is silyl). When the hydroxyl protecting group is an ester protecting group, R 4 can be acetyl, propionyl, benzoyl or pivaloyl, preferably acetyl or propionyl, more preferably acetyl. When the hydroxyl protecting group is a silyl ether protecting group, R 4 can be trimethylsilyl, triisopropylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, tris(tert-butyl)silyl, preferably tert-butyldiphenylsilyl or tris(tert-butyl)silyl, more preferably tert-butyldiphenylsilyl. Preferably, R 4 is acetyl or tert-butyldiphenylsilyl.

[0031] In some embodiments, in the method for preparing the compound of formula I, R 1 is methylsulfonylethyl; R 2 is methyl; R 3 is fluorine; R 4 is acetyl.

[0032] In some embodiments, in the method for preparing the compound of formula I, R 1 is methylsulfonylethyl; R 2 is methyl; R 3 is fluorine; R 4 is tert-butyldiphenylsilyl.

[0033] In some embodiments, in the method for preparing the compound of formula I, the reaction conditions for removing R 4 protecting group (such as solvent and its dosage, reagent for removing R 4 protecting group and its dosage, reaction time, etc.) can be the conventional conditions for this type of reaction in the art, and can be adjusted according to the type of hydroxyl protecting group.

[0034] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is an ester protecting group (such as when R 4 is acetyl), the deprotecting reagent for removing R 4 protecting group can be sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate or acetyl chloride / methanol, preferably potassium carbonate or acetyl chloride / methanol, and further preferably acetyl chloride / methanol.

[0035] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is an ester protecting group (such as when R 4 is acetyl), the molar ratio of the deprotecting reagent (such as acetyl chloride) for removing R 4 protecting group to the compound of formula II can be 0.5 - 2, preferably 0.5 - 1, and further preferably 0.5.

[0036] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is an ester protecting group (such as when R 4 is acetyl), the solvent for removing R 4 protecting group can be the conventional solvent used in the art for this type of reaction, such as methanol, ethanol, isopropanol, dichloromethane or a mixture of any two or more of them. Preferably, it is "a mixed solvent of methanol and dichloromethane" or "a mixed solvent of ethanol and dichloromethane", and further preferably a mixed solvent of methanol and dichloromethane. In the mixed solvent of methanol and dichloromethane, the volume ratio of methanol to dichloromethane can be 1:20 - 2:1, preferably 1:5 - 1:1, and further preferably 1:1.

[0037] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is an ester protecting group (such as when R 4 is acetyl), the temperature for the reaction of removing R 4 protecting group is 10 - 50 °C, such as 20 - 30 °C.

[0038] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is an ester protecting group (such as when R 4 is acetyl), the reaction for removing R 4The operation of the protecting group reaction can be a conventional operation for this type of reaction in the art. For example, it may include the following steps: acetyl chloride is added in batches (such as dropwise addition) to a solution of the compound of formula II, and the reaction is carried out after the addition is complete; preferably, the temperature of the system is controlled at 0-5 °C during the addition of acetyl chloride.

[0039] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is an ester protecting group (for example, when R 4 is an acetyl group), the progress of the reaction for removing the R 4 protecting group can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC or NMR, etc.), and generally, the reaction end point is when the compound of formula II is no longer detected. In some embodiments, the reaction time for removing the R 4 protecting group can be 2-8 hours, preferably 2-5 hours, and more preferably 2-3 hours.

[0040] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is an ester protecting group (for example, when R 4 is an acetyl group), after the reaction for removing the R 4 protecting group is completed, it may further include a post-treatment step: the reaction solution is extracted and washed, and the organic phase is concentrated to obtain the crude product of the compound of formula I; optionally, the crude product of the compound of formula I is purified by silica gel column chromatography to obtain the product of the compound of formula I.

[0041] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is a silyl ether protecting group (for example, when R 4 is tert-butyldiphenylsilyl), the deprotecting reagent used for removing the R 4 protecting group can be a conventional reagent used for this type of reaction in the art, such as lithium hydroxide, tetrabutylammonium fluoride / acetic acid, sodium hydroxide, pyridine hydrogen fluoride complex, tert-butylammonium fluoride or tert-butylammonium fluoride / acetic acid, preferably tert-butylammonium fluoride or tert-butylammonium fluoride / acetic acid, and more preferably tert-butylammonium fluoride / acetic acid.

[0042] In some embodiments, in the method for preparing the compound of formula I, in the method for preparing the compound of formula I, when the hydroxyl protecting group is a silyl ether protecting group (for example, when R 4 is tert-butyldiphenylsilyl), the molar ratio of the deprotecting reagent (such as tert-butylammonium fluoride or tert-butylammonium fluoride / acetic acid) used for removing the R 4 protecting group to the compound of formula II can be 1.2-3, preferably 1.2-1.6, and more preferably 1.5.

[0043] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is a silyl ether protecting group (for example, when R 4 is tert-butyldiphenylsilyl), the solvent used for removing the R 4 protecting group can be a conventional solvent used in the art for such reactions, such as methanol, ethanol, isopropanol, dichloromethane, or a mixture of any two or more thereof. Preferably, it is a "mixed solvent of methanol and dichloromethane" or a "mixed solvent of ethanol and dichloromethane", and more preferably a mixed solvent of methanol and dichloromethane. In the mixed solvent of methanol and dichloromethane, the volume ratio of methanol to dichloromethane can be 1:20 - 2:1, preferably 1:20 - 1:10, and more preferably 1:20.

[0044] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is a silyl ether protecting group (for example, when R 4 is tert-butyldiphenylsilyl), the temperature of the reaction for removing the R 4 protecting group is 10 - 50 °C, such as 20 - 30 °C.

[0045] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is a silyl ether protecting group (for example, when R 4 is tert-butyldiphenylsilyl), the operation of the reaction for removing the R 4 protecting group can be a conventional operation in the art for such reactions. For example, it may include the following steps: adding tert-butylammonium fluoride and acetic acid to the solution of the compound of formula II in batches, and reacting after adding.

[0046] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is a silyl ether protecting group (for example, when R 4 is tert-butyldiphenylsilyl), the reaction progress of removing the R 4 protecting group can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC, or NMR, etc.), and generally, the reaction end point is when the compound of formula II is no longer detected. In some embodiments, the reaction time for removing the R 4 protecting group can be 10 - 20 hours, preferably 12 - 16 hours, and more preferably 14 - 16 hours.

[0047] In some embodiments, in the method for preparing the compound of formula I, when the hydroxyl protecting group is a silyl ether protecting group (for example, when R 4 is tert-butyldiphenylsilyl), after the reaction for removing the R 4 protecting group is completed, it may further include a post-treatment step: separating the solid and liquid of the reaction solution, and the obtained solid is the product of the compound of formula I.

[0048] In some embodiments, R 4 is an acetyl group;

[0049] Preferably, the deprotecting reagent used for removing the R 4 protecting group is acetyl chloride / methanol;

[0050] Preferably, the solvent used for removing the R 4 protecting group is a mixed solvent of methanol and dichloromethane.

[0051] In some embodiments, R 4 is tert-butyldiphenylsilyl;

[0052] Preferably, the deprotecting reagent used for removing the R 4 protecting group is tetrabutylammonium fluoride / acetic acid;

[0053] Preferably, the solvent used for removing the R 4 protecting group is a mixed solvent of methanol and dichloromethane.

[0054] The method for preparing the compound of formula I may further include a method for preparing the compound of formula II, which may include the following steps: coupling the compound of formula III and N-succinimidyl 6-(maleimidyl)hexanoate in a solvent to obtain the compound of formula II;

[0055]

[0056] wherein the definitions of R 1 , R 2 , R 3 and R 4 are as defined above.

[0057] In some embodiments, in the method for preparing the compound of formula II, the molar ratio of N-succinimidyl 6-(maleimidyl)hexanoate to the compound of formula III may be 1-5, preferably 1-2, more preferably 1.0-1.5, and even more preferably 1.0.

[0058] In some embodiments, in the method for preparing the compound of formula II, the solvent can be a solvent conventional in such reactions in the art, such as an amide solvent, a chloroalkane solvent, an ether solvent, a nitrile solvent, or a mixture of any two or more thereof. Preferably, it is an amide solvent, a chloroalkane solvent, or a mixture thereof. More preferably, it is an amide solvent or a chloroalkane solvent. Even more preferably, it is a chloroalkane solvent. Among them, the amide solvent is preferably N,N-dimethylformamide, N,N-dimethylacetamide, or a mixture thereof. More preferably, it is N,N-dimethylformamide. The chloroalkane solvent is preferably dichloromethane, chloroform, dichloroethane, or a mixture of any two or more thereof. More preferably, it is dichloromethane. The ether solvent is preferably tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether, or a mixture of any two or more thereof. More preferably, it is tetrahydrofuran. The nitrile solvent is preferably acetonitrile. In some embodiments, in the method for preparing the compound of formula II, the solvent is a chloroalkane solvent, such as dichloromethane.

[0059] In some embodiments, in the method for preparing the compound of formula II, the reaction temperature can be a temperature conventional in such reactions in the art, such as 0-50 °C. Preferably, it is 25-40 °C. More preferably, it is 40 °C.

[0060] In some embodiments, in the method for preparing the compound of formula II, the operation of the coupling reaction can be a conventional operation in such reactions in the art. For example, it can include the following steps: stirring a mixture of the compound of formula III, the 6-(maleimide)hexanoyl compound, and a solvent to carry out the coupling reaction.

[0061] In some embodiments, in the method for preparing the compound of formula II, the progress of the coupling reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC, or NMR, etc.). Generally, the reaction end point is when the compound of formula III is no longer detected. The reaction time of the coupling reaction can be 1-24 hours. Preferably, it is 12-20 hours. More preferably, it is 16 hours.

[0062] In some embodiments, in the method for preparing the compound of formula II, after the coupling reaction is completed, it can further include a post-treatment step: removing the solvent from the reaction solution, and the obtained residue is purified to obtain the compound of formula II. The purification can be carried out by conventional purification methods in the art, such as trituration, crystallization, preparative chromatography, or silica gel column chromatography, etc. Preferably, the method of silica gel column chromatography is selected. Among them, the eluent is preferably a mixture of dichloromethane and methanol, and the elution gradient is preferably 50:1-10:1 (V / V). More preferably, it is 50:1-15:1 (V / V).

[0063] The preparation method of the compound of formula II may further include a preparation method of the compound of formula III, which may include the following steps: performing a reduction reaction on the compound of formula IV and a reducing agent in an organic solvent and in the presence of an acid buffer to obtain a compound of formula III;

[0064]

[0065] Among them, R 1 , R 2 , R 3 and R 4 The definition of is as mentioned above.

[0066] In some embodiments, in the method for preparing the compound of formula III, the reducing agent can be a conventional reducing agent for such reactions in the art, preferably triphenylphosphine, tri-tert-butylphosphine or trimethylphosphine, and more preferably trimethylphosphine.

[0067] In some embodiments, in the method for preparing the compound of formula III, the molar ratio of the reducing agent to the compound of formula IV can be 1-5, preferably 1-2, more preferably 1.0-1.5, and even more preferably 1.1-1.3.

[0068] In some embodiments, in the method for preparing the compound of formula III, the organic solvent may be a conventional solvent for such reactions in the art, preferably an ether solvent, such as tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether or a mixture of any two or more thereof, more preferably tetrahydrofuran.

[0069] In some embodiments, in the method for preparing the compound of formula III, the volume mass ratio of the organic solvent to the compound of formula IV can be 5-50 mL / g, preferably 10-20 mL / g, and further preferably 13-19 mL / g.

[0070] In some embodiments, in the preparation method of the compound of formula III, the acid buffer can be an acid buffer conventional in this field for such reactions, such as an acetate buffer, a formic acid buffer, preferably an acetate buffer. The pH of the acid buffer can be 4.0-6.0, preferably 4.5-5.5, and more preferably 5.0. In some embodiments, the acid buffer is an acetate buffer having a pH of 4.0-6.0 (preferably 4.5-5.5, and more preferably 5.0).

[0071] In some embodiments, in the method for preparing the compound of formula III, the volume ratio of the organic solvent to the acid buffer solution may be 1-5, preferably 1-2, further preferably 1.25-1.35, and most preferably 1.28-1.30.

[0072] In some embodiments, in the method for preparing the compound of formula III, the temperature of the reduction reaction can be the temperature conventional for such reactions in the art, for example, 0 - 20°C, preferably 0 - 10°C, and more preferably 0 - 5°C.

[0073] In some embodiments, in the method for preparing the compound of formula III, the operation of the reduction reaction can be the conventional operation for such reactions in the art. For example, it can include the following steps: stirring a mixture of an organic solvent, an acid buffer solution, the compound of formula IV, and a reducing agent to carry out the reduction reaction.

[0074] In some embodiments, in the method for preparing the compound of formula III, the progress of the reduction reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC, or NMR, etc.). Generally, the reaction end point is when the compound of formula IV is no longer detected. The reaction time of the reduction reaction can be 1 - 24 hours, preferably 2 - 5 hours, and more preferably 2 hours.

[0075] In some embodiments, in the method for preparing the compound of formula III, after the reduction reaction, it can further include a post - treatment step: extracting the reaction solution, removing the solvent from the obtained organic phase of the extraction, and purifying the obtained residue to obtain the compound of formula III. The purification can be carried out by conventional purification methods in the art, such as trituration, crystallization, preparative chromatography, or silica gel column chromatography, etc. Preferably, the method of silica gel column chromatography is selected. Among them, the eluent is preferably a mixture of dichloromethane and methanol, and the elution gradient is preferably 50:1 - 10:1, and more preferably 20:1 - 10:1.

[0076] The method for preparing the compound of formula III can further include a method for preparing the compound of formula IV, which can include the following steps: carrying out a substitution reaction on the compound of formula V and the compound of formula VIa in a solvent in the presence of a base to obtain the compound of formula IV;

[0077]

[0078] wherein, R 1 、R 2 、R 3 and R 4 are as described above.

[0079] In some embodiments, in the method for preparing the compound of formula IV, the molar ratio of the compound of formula V to the compound of formula VIa can be 1 - 5, preferably 1 - 2, and more preferably 1.

[0080] In some embodiments, in the preparation method of the compound of formula IV, the base can be a base conventional in such reactions in the art, such as an organic base, an inorganic base or a mixture thereof, preferably an organic base. Among them, the organic base is preferably potassium tert-butoxide, sodium methoxide, triethylamine, DMAP, pyridine, panpidine or a mixture of any two or more thereof, and more preferably sodium methoxide. The inorganic base is preferably an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof, and more preferably potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof. In some embodiments, in the preparation method of the compound of formula IV, the base is sodium methoxide.

[0081] In some embodiments, in the preparation method of the compound of formula IV, the molar ratio of the base used to the compound of formula VIa can be 1-5, preferably 1-2, and more preferably 1.5.

[0082] In some embodiments, in the preparation method of the compound of formula IV, the solvent can be a solvent conventional in such reactions in the art, preferably an aprotic organic solvent, such as an ether solvent, a chloroalkane solvent, a nitrile solvent or a mixture of any two or more thereof, preferably an ether solvent or a chloroalkane solvent. The ether solvent can be tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether or a mixture of any two or more thereof, preferably 1,4-dioxane. The chloroalkane solvent can be dichloromethane, dichloroethane, chloroform or a mixture of any two or more thereof, preferably dichloromethane. The nitrile solvent can be acetonitrile. In some embodiments, when R 4 is a silyl ether protecting group such as tert-butyldiphenylsilyl, the solvent can be a chloroalkane solvent, preferably dichloromethane. In some embodiments, when R 4 is an ester protecting group such as acetyl, the solvent can be an ether solvent, preferably 1,4-dioxane.

[0083] In some embodiments, in the preparation method of the compound of formula IV, the reaction temperature can be a conventional temperature for such reactions in the art, such as 0-80 °C. In some embodiments, when R 4 is an ester protecting group such as acetyl, the reaction temperature can be 40-60 °C, and more preferably 60 °C. In some embodiments, when R 4 is a silyl ether protecting group such as tert-butyldiphenylsilyl, the reaction temperature can be 0-20 °C, preferably 0-5 °C.

[0084] In some embodiments, in the method for preparing the compound of formula IV, the progress of the reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC or NMR, etc.), and generally, the reaction end point is when the compound of formula VIa is no longer detected. The reaction time of the substitution reaction can be 2 - 12 hours. In some embodiments, when R 4 is a silyl ether protecting group such as tert-butyldiphenylsilyl, the reaction time can be 3 - 8 hours, such as 4 - 5 hours. In some embodiments, when R 4 is an ester protecting group such as acetyl, the reaction time can be 2 - 3 hours, such as 2 hours.

[0085] In some embodiments, in the method for preparing the compound of formula IV, after the substitution reaction is completed, it may further include a post-treatment step, and the post-treatment step can be a conventional post-treatment step for this type of reaction in the art. In some embodiments, when R 4 is an ester protecting group such as acetyl, the post-treatment step may include: removing the solvent from the reaction solution, washing the organic phase, removing the solvent from the organic phase, and purifying the obtained residue. Among them, the organic phase in the washing can be ethyl acetate or dichloromethane, preferably dichloromethane. The aqueous phase in the washing can be an aqueous solution of an acid, water, and / or saturated brine; the aqueous solution of the acid can be 0.1N hydrochloric acid, 0.05N sulfuric acid, or a mixture thereof, preferably 0.1N hydrochloric acid. Preferably, the washing can include washing the organic phase successively with an aqueous solution of an acid, water, and saturated brine, preferably successively with 0.1N dilute acid, water, and saturated brine. In some embodiments, the purification can adopt conventional purification methods in the art, such as trituration, crystallization, preparative chromatography, or silica gel column chromatography, etc., preferably the method of column silica gel column chromatography, and the eluent used is preferably a mixture of dichloromethane and methanol, and the elution gradient is preferably 100:1 - 10:1 (V / V), more preferably 60:1 - 10:1 (V / V). In some embodiments, when R 4 is a silyl ether protecting group such as tert-butyldiphenylsilyl, the post-treatment step may include: washing the reaction solution, and concentrating the obtained organic phase to obtain the product of the compound of formula IV.

[0086] In some embodiments, in the method for preparing the compound of formula IV, the substitution reaction is preferably carried out under anhydrous conditions.

[0087] The method for preparing the compound of formula IV may further include a method for preparing the compound of formula VIa, which may include the following steps: condensing the compound of formula VIb and bromoacetic acid in the presence of a condensing agent and a base to obtain the compound of formula VIa;

[0088]

[0089] Among them, R 2 , R 3 and R 4 are defined as described above.

[0090] In some embodiments, in the method for preparing the compound of formula VIa, the solvent for the condensation reaction can be a conventional solvent for such reactions in the art, such as dichloromethane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, or a mixture of any two or more thereof. Preferably, it is dichloromethane, N,N-dimethylformamide, or a mixture thereof, and more preferably dichloromethane.

[0091] In some embodiments, in the method for preparing the compound of formula VIa, the molar ratio of the bromoacetic acid to the compound of formula VIb can be 1-5, preferably 1.5-3.0, and more preferably 1.5-2.0.

[0092] In some embodiments, in the method for preparing the compound of formula VIa, the condensing agent can be a conventional condensing agent for condensation reactions in the art, such as dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) or its salt, 2-(7-azabenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU), propylphosphonic anhydride (T 3 P), benzotriazol-N,N,N',N'-tetramethyluronium hexafluorophosphate (HBTU), diphenylphosphoryl azide (DPPA), 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine or its salt (such as 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride). Preferably, it is dicyclohexylcarbodiimide (DCC), 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine or its salt, more preferably 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine or its salt, and further preferably 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride.

[0093] In some embodiments, in the method for preparing the compound of formula VIa, the molar ratio of the condensing agent to the compound of formula VIb can be 1-5, preferably 1.5-3.0, and more preferably 1.5-2.0.

[0094] In some embodiments, in the method for preparing the compound of formula VIa, the base used in the condensation reaction can be a conventional base for condensation reactions in the art, such as N,N-diisopropylethylamine (DIEA), triethylamine, or 1,8-diazabicycloundec-7-ene (DBU), preferably triethylamine or N,N-diisopropylethylamine, and more preferably N,N-diisopropylethylamine.

[0095] In some embodiments, in the method for preparing the compound of formula VIa, the molar ratio of the base used in the condensation reaction to the compound of formula VIb can be 1 - 5, preferably 2 - 4, more preferably 2.0 - 3.0, and even more preferably 2.0 - 2.5.

[0096] In some embodiments, in the method for preparing the compound of formula VIa, the temperature of the condensation reaction can be a conventional temperature for such reactions in the art, for example, 20 - 50 °C, preferably 20 - 30 °C.

[0097] In some embodiments, in the method for preparing the compound of formula VIa, the condensation reaction is preferably carried out under the protection of an inert gas, for example, in a nitrogen or helium environment.

[0098] In some embodiments, in the method for preparing the compound of formula VIa, the progress of the condensation reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC, or NMR, etc.), and generally, the reaction end point is when the compound of formula VIb is no longer detected. The reaction time of the condensation reaction can be 5 - 20 hours, more preferably 13 - 15 hours, and even more preferably 13 hours.

[0099] In some embodiments, in the method for preparing the compound of formula VIa, the purification of the compound of formula VIa can be carried out by conventional purification methods in the art, such as slurrying, crystallization, preparative chromatography, or silica gel column chromatography, etc. Preferably, the method of column silica gel column chromatography is selected. The eluent used is preferably a mixture of dichloromethane and methanol, and the elution gradient can be 100:1 - 10:1 (V / V), preferably 100:1 - 50:1 (V / V), and more preferably 50:1 (V / V).

[0100] The method for preparing the compound of formula VIa may further include a method for preparing the compound of formula VIb, which may include the following steps: removing the 4-methoxytriphenylmethyl group connected to the amino group in the compound of formula VIc to obtain the compound of formula VIb;

[0101]

[0102] wherein, R 2 、R 3 and R4 As described above.

[0103] In some embodiments, in the method for preparing the compound of formula VIb, the solvent used in the 4 - methoxytrityl deprotection reaction is a reagent commonly used in this type of reaction in the art, such as chloroform, dichloromethane or a mixture thereof, preferably dichloromethane.

[0104] In some embodiments, in the method for preparing the compound of formula VIb, the deprotection reagent used for 4 - methoxytrityl deprotection is a conventional deprotection reagent for this type of reaction in the art, such as triisopropylsilane or triethylsilane, preferably triethylsilane.

[0105] In some embodiments, in the method for preparing the compound of formula VIb, the molar ratio of the deprotection reagent used for 4 - methoxytrityl deprotection to the compound of formula VIc can be 1 - 5, preferably 1 - 3, and more preferably 1.2 - 2.5.

[0106] In some embodiments, in the method for preparing the compound of formula VIb, the temperature of the 4 - methoxytrityl deprotection reaction can be a conventional temperature for this type of reaction in the art, such as - 20 to 10 °C, preferably - 10 to 5 °C, and more preferably - 5 to 5 °C.

[0107] In some embodiments, in the method for preparing the compound of formula VIb, the 4 - methoxytrityl deprotection reaction is preferably carried out under the protection of an inert gas, such as in a nitrogen or helium atmosphere.

[0108] In some embodiments, in the method for preparing the compound of formula VIb, the progress of the 4 - methoxytrityl deprotection reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC or NMR, etc.), and generally the reaction end point is when the compound of formula VIc is no longer detected. In some embodiments, the time of the 4 - methoxytrityl deprotection reaction can be 1 - 5 hours, more preferably 1 - 2 hours, and even more preferably 1 - 1.5 hours.

[0109] In some embodiments, in the preparation method of the compound of formula VIb, after the reaction of removing 4 - methoxytrityl is completed, a post - treatment step may further be included. The post - treatment step may be a conventional post - treatment step for this type of reaction in the art. For example, it may include the following steps: after the reaction is completed, an ether solvent is added dropwise to the reaction system to precipitate the compound of formula VIb from the mixed solution, and the precipitated solid is separated to obtain the crude product of the compound of formula VIb; the ether solvent may be methyl tert - butyl ether, anisole, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether or a mixture of any two or more of them, preferably methyl tert - butyl ether or anisole, and further preferably methyl tert - butyl ether. The crude product of the compound of formula VIb may be purified to obtain the product of the compound of formula VIb. The purification may include: dissolving the crude product of the compound of formula VIb in a chloroalkane solvent, and then adding dropwise an ether solvent to precipitate the compound of formula VIb, and separating the precipitated solid to obtain the product of the compound of formula VIb; the chloroalkane solvent may be dichloromethane, dichloroethane or a mixture thereof, preferably dichloromethane; the ether solvent may be methyl tert - butyl ether, anisole or a mixture thereof, preferably methyl tert - butyl ether; the volume - molar ratio of the chloroalkane solvent used to the compound of formula VIc may be 10 - 30 mL / mmol, preferably 20 - 25 mL / mmol, and further preferably 20 mL / mmol; the volume ratio of the ether solvent used to the chloroalkane solvent may be 2 - 4, preferably 2 - 3, and further preferably 2.

[0110] The preparation method of the compound of formula VIb may further include the preparation method of the compound of formula VIc, which may include the following steps: carrying out a hydroxyl - protecting reaction on the compound of formula VId and a hydroxyl - protecting reagent to obtain the compound of formula VIc;

[0111]

[0112] wherein, R 2 、R 3 and R 4 are as described above.

[0113] In some embodiments, in the preparation method of the compound of formula VIc, the hydroxyl - protecting reagent used may be a conventional hydroxyl - protecting reagent in the art, such as acetic anhydride, propionic anhydride, acetyl chloride, propionyl chloride, tert - butyldimethylchlorosilane or tert - butyldiphenylchlorosilane, preferably acetic anhydride, acetyl chloride or tert - butyldiphenylchlorosilane, and further preferably acetic anhydride or tert - butyldiphenylchlorosilane.

[0114] In some embodiments, in the preparation method of the compound of formula VIc, the molar ratio of the hydroxyl - protecting reagent used to the compound of formula VId may be 1 - 2, preferably 1 - 1.5, and further preferably 1.1 - 1.44.

[0115] In some embodiments, in the method for preparing the compound of formula VIc, the hydroxy protection reaction is carried out in the presence of a base. The base can be a common base used in this type of reaction in the art, such as triethylamine, 4-dimethylaminopyridine, N,N-diisopropylethylamine, 1,8-diazabicyclo-bicyclo(5,4,0)-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-ene, N-methylmorpholine, tetramethylethylenediamine, pyridine or a mixture of any two or more thereof, preferably triethylamine, 4-dimethylaminopyridine, N,N-diisopropylethylamine or a mixture of any two or more thereof. In some embodiments, in the method for preparing the compound of formula VIc, when the hydroxy protection reagent used is acetic anhydride, the base used is preferably triethylamine, 4-dimethylaminopyridine or a mixture thereof, more preferably a mixture of triethylamine and 4-dimethylaminopyridine; in the mixture of triethylamine and 4-dimethylaminopyridine, the molar ratio of triethylamine to the compound of formula VId can be 1-5, preferably 1.5-2.0, more preferably 1.6-1.7; the molar ratio of 4-dimethylaminopyridine to the compound of formula VId can be 1-5, preferably 2-3, more preferably 2. In some embodiments, in the method for preparing the compound of formula VIc, when the protecting reagent used is tert-butyldiphenylchlorosilane, the base used is preferably N,N-diisopropylethylamine; the molar ratio of N,N-diisopropylethylamine to the compound of formula VId can be 1-5, preferably 2-3, more preferably 2.

[0116] In some embodiments, in the method for preparing the compound of formula VIc, the operation of the hydroxy protection reaction can be a conventional operation for this type of reaction in the art, for example, it can include the following steps: adding (such as dropwise adding) the hydroxy protection reagent to the solution of the compound of formula VId in batches; optionally, controlling the temperature of the reaction system to be -5 to 10 °C (such as 0-10 °C or 0-5 °C) during the process of adding in batches.

[0117] In some embodiments, in the method for preparing the compound of formula VIc, the solvent for the hydroxy protection reaction can be a conventional solvent for this type of reaction in the art, such as dichloromethane, dichloroethane, N,N-dimethylformamide, N,N-dimethylacetamide or a mixture of any two or more thereof; preferably dichloromethane or N,N-dimethylformamide. In some embodiments, when the hydroxy protection reagent used is acetic anhydride, the solvent used can be dichloromethane. In some embodiments, when the hydroxy protection reagent used is tert-butyldiphenylchlorosilane, the solvent used can be N,N-dimethylformamide.

[0118] In some embodiments, in the method for preparing the compound of formula VIc, the temperature of the hydroxyl protection reaction can be the conventional temperature for such reactions in the art, for example, 0 - 40 °C, preferably 10 - 30 °C, and more preferably 20 - 30 °C.

[0119] In some embodiments, in the method for preparing the compound of formula VIc, the hydroxyl protection reaction is preferably carried out under the protection of an inert gas, for example, in a nitrogen or helium environment.

[0120] In some embodiments, in the method for preparing the compound of formula VIc, the progress of the hydroxyl protection reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC or NMR, etc.), and generally, the reaction end point is when the compound of formula VId is no longer detected. The reaction time of the hydroxyl protection reaction can be 2 - 10 hours, more preferably 3 - 5 hours, and even more preferably 3 hours.

[0121] The method for preparing the compound of formula VIc may further include the method for preparing the compound of formula VId, which may include the following steps:

[0122] (i) React irinotecan with trimethylchlorosilane;

[0123] (ii) React the reaction solution of step (i) with 4 - methoxytriphenylmethyl chloride in the presence of a base to obtain the compound of formula VId;

[0124]

[0125] wherein, R 2 and R 3 are as defined above.

[0126] In some embodiments, in the method for preparing the compound of formula VId, the solvents used in the reactions of step (i) and step (ii) can be the conventional solvents for such reactions in the art, such as dichloromethane, chloroform, dichloroethane or a mixture of any two or more of them, and preferably dichloromethane.

[0127] In some embodiments, in the method for preparing the compound of formula VId, in the reaction of step (i), the molar ratio of trimethylchlorosilane to irinotecan used can be 1 - 3, preferably 1.2 - 2.0, and more preferably 1.2.

[0128] In some embodiments, in the method for preparing the compound of formula VId, the reaction temperature of step (i) can be 20 - 60 °C, preferably 40 - 45 °C, and more preferably 45 °C.

[0129] In some embodiments, in the method for preparing the compound of formula VId, the reaction progress of step (i) can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC or NMR, etc.), and generally the reaction end point is when irinotecan is no longer detected. In some embodiments, the reaction time of step (i) can be 1 - 5 hours, preferably 1 - 2 hours, and more preferably 1 hour.

[0130] In some embodiments, in the method for preparing the compound of formula VId, the molar ratio of 4-methoxytriphenylmethyl chloride in step (ii) to irinotecan in step (i) can be 1 - 3, preferably 1.2 - 2.0, and more preferably 1.2.

[0131] In some embodiments, in the method for preparing the compound of formula VId, the base in step (ii) can be a commonly used base in the art for such reactions, such as triethylamine, 4-dimethylaminopyridine, N,N-diisopropylethylamine, 1,8-diazabicyclo-bicyclo(5,4,0)-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-ene, N-methylmorpholine, tetramethylethylenediamine, pyridine or a mixture of any two or more thereof, preferably triethylamine, 4-dimethylaminopyridine, N,N-diisopropylethylamine or a mixture of any two or more thereof, and more preferably N,N-diisopropylethylamine.

[0132] In some embodiments, in the method for preparing the compound of formula VId, the molar ratio of the base in step (ii) to irinotecan in step (i) can be 2 - 5, preferably 3 - 4, and more preferably 3.

[0133] In some embodiments, in the method for preparing the compound of formula VId, the operation of step (ii) can include the following steps: adding 4-methoxytriphenylmethyl chloride and the base to the reaction solution of step (i), and controlling the reaction system temperature to be 0 - 10 °C (such as 0 - 5 °C, such as 0 °C) during the addition process.

[0134] In some embodiments, in the method for preparing the compound of formula VId, the reaction temperature of step (ii) can be the conventional temperature for such reactions in the art, for example, 0 - 40 °C, preferably 10 - 30 °C, and more preferably 20 - 30 °C.

[0135] In some embodiments, in the method for preparing the compound of formula VId, the reaction progress of step (ii) can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC or NMR, etc.), and generally the reaction end point is when the product of step (i) is no longer detected. The reaction time of step (ii) can be 12 - 24 hours, more preferably 16 - 24 hours, and even more preferably 16 - 18 hours.

[0136] The method for preparing the compound of formula IV may further include a method for preparing the compound of formula V, which may include the following steps: reacting the compound of formula VII with paraformaldehyde in the presence of a base to obtain the compound of formula V;

[0137]

[0138] wherein, R 1 As described above.

[0139] In some embodiments, in the method for preparing the compound of formula V, the molar ratio of paraformaldehyde in terms of formaldehyde to the compound of formula VII is 1-3, preferably 1-2, and more preferably 1.5.

[0140] In some embodiments, in the method for preparing the compound of formula V, the base can be a base conventional in such reactions in the art, such as an organic base, an inorganic base or a mixture thereof, preferably an inorganic base. Among them, the organic base is preferably potassium tert-butoxide, sodium methoxide, triethylamine, DMAP, pyridine, panpipidine or a mixture of any two or more thereof, and more preferably sodium methoxide. The inorganic base is preferably an alkali metal carbonate, an alkali metal hydroxide, an alkali metal phosphate or a mixture of any two or more thereof, and more preferably sodium bicarbonate, sodium carbonate, potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof. In some embodiments, in the method for preparing the compound of formula V, the base is sodium bicarbonate.

[0141] In some embodiments, in the method for preparing the compound of formula V, the molar ratio of sodium bicarbonate to the compound of formula VII is 1-4, preferably 1-2, and more preferably 1.4.

[0142] In some embodiments, in the method for preparing the compound of formula V, the solvent can be a solvent conventional in such reactions in the art, preferably a mixed system of an ether solvent and water; the ether solvent can be tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether or a mixture of any two or more thereof, and preferably 1,4-dioxane.

[0143] In some embodiments, in the method for preparing the compound of formula V, the reaction temperature can be a conventional temperature for such reactions in the art, such as 10-40 °C, preferably 25-40 °C, and more preferably 25-30 °C.

[0144] In some embodiments, in the method for preparing the compound of formula V, the operation of the reaction can be the conventional operation of such reactions in the art. For example, it includes the following steps: adding sodium bicarbonate in batches to a mixture of the compound of formula VII, paraformaldehyde and a solvent, and stirring to carry out the reaction.

[0145] In some embodiments, in the method for preparing the compound of formula V, the progress of the reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC or NMR, etc.), and generally, the reaction end point is when the compound of formula VII is no longer detected. The reaction time of the reaction can be 1 to 60 hours, preferably 12 to 40 hours, more preferably 16 - 35 hours, and even more preferably 24 hours.

[0146] In some embodiments, in the method for preparing the compound of formula V, after the substitution reaction is completed, the following post-treatment steps can further be included: separating the reaction solution by solid-liquid separation, removing the solvent from the obtained liquid phase, and directly using the obtained residue for the next reaction.

[0147] The method for preparing the compound of formula V can further include a method for preparing the compound of formula VII, which can include the following steps: reacting the compound of formula VIII with a sulfonyl azide compound in the presence of a base and a catalyst in a solvent to obtain the compound of formula VII;

[0148]

[0149] wherein, R 1 As described above.

[0150] In some embodiments, in the method for preparing the compound of formula VII, the sulfonyl azide compound can be 1H-imidazole-1-sulfonyl azide hydrochloride, 2-azido-1,3-dimethylimidazolium hexafluorophosphate, trifluoromethanesulfonyl azide, p-toluenesulfonyl azide or methanesulfonyl azide, preferably 1H-imidazole-1-sulfonyl azide hydrochloride.

[0151] In some embodiments, in the method for preparing the compound of formula VII, the molar ratio of the sulfonyl azide compound to the compound of formula VIII is 1.0:1 - 1.5:1, preferably 1.0:1 - 1.2:1, and more preferably 1.02:1.

[0152] In some embodiments, in the method for preparing the compound of formula VII, the base can be a base conventional in such reactions in the art, such as an organic base, an inorganic base or a mixture thereof, preferably an inorganic base; wherein, the inorganic base is preferably an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof, more preferably potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof, still more preferably potassium carbonate; the organic base is preferably potassium tert-butoxide, triethylamine, DMAP, pyridine, panpidine, 2,6-dimethylpyridine or a mixture of any two or more thereof. In some embodiments, in the method for preparing the compound of formula V, the base is an alkali metal carbonate, such as potassium carbonate.

[0153] In some embodiments, in the method for preparing the compound of formula VII, the molar ratio of the base to the compound of formula VIII is 1.5 - 3.0, preferably 2.0 - 2.5, more preferably 2.0.

[0154] In some embodiments, in the method for preparing the compound of formula VII, the catalyst can be a catalyst conventional in such reactions in the art, such as a copper salt, preferably copper sulfate, more preferably copper sulfate pentahydrate.

[0155] In some embodiments, in the method for preparing the compound of formula VII, the molar ratio of the copper salt to the compound of formula VIII can be 0.1 - 0.5, preferably 0.1 - 0.3, more preferably 0.1 - 0.2, most preferably 0.1.

[0156] In some embodiments, in the method for preparing the compound of formula VII, the solvent can be a solvent conventional in such reactions in the art, preferably a mixed solvent of an organic solvent and water. The organic solvent can be an alcohol solvent, a chloroalkane solvent, an ether solvent or a mixture of any two or more thereof, preferably a mixture of an alcohol solvent and a chloroalkane solvent; the alcohol solvent can be methanol, ethanol, isopropanol or a mixture of any two or more thereof, preferably methanol; the chloroalkane solvent can be dichloromethane, chloroform, dichloroethane or a mixture of any two or more thereof, preferably dichloromethane; the ether solvent is preferably tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether or a mixture of any two or more thereof. In some embodiments, in the method for preparing the compound of formula VII, the solvent is a mixed solvent of methanol, dichloromethane and water.

[0157] In some embodiments, in the method for preparing the compound of formula VII, the reaction temperature can be a conventional temperature for such reactions in the art, such as 10 - 40 °C, preferably 25 - 40 °C, more preferably 25 - 30 °C.

[0158] In some embodiments, in the method for preparing the compound of formula VII, the operation of the reaction can be the conventional operation of such reactions in the art, for example, including the following steps: adding the sulfonyl azide compound to a mixed system of the compound of formula VIII, a base, a catalyst and a solvent (preferably, the sulfonyl azide compound is added after the mixed system becomes clear), and stirring to carry out the reaction.

[0159] In some embodiments, in the method for preparing the compound of formula VII, the progress of the reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC or NMR, etc.), and generally, the reaction end point is when the compound of formula VIII is no longer detected. The reaction time of the reaction can be 1 to 24 hours, preferably 12 to 20 hours, more preferably 16 - 20 hours, and even more preferably 16 hours.

[0160] In some embodiments, in the method for preparing the compound of formula VII, after the reaction is completed, the following post-treatment steps can further be included: removing the organic solvent from the reaction solution, extracting (for example, extracting with dichloromethane), and recrystallizing the obtained organic phase with ethanol and activated carbon to obtain the compound of formula VII.

[0161] The method for preparing the compound of formula VII can further include the method for preparing the compound of formula VIII, which can include the following steps: carrying out a de-Fmoc reaction on the compound of formula IX in the presence of a base and in an organic solvent to obtain the compound of formula VIII;

[0162]

[0163] wherein, R 1 As described above.

[0164] In some embodiments, in the method for preparing the compound of formula VIII, the base can be a conventional base for such reactions in the art, for example, an organic base, an inorganic base or a mixture thereof, preferably an organic base; wherein, the organic base is preferably diethylamine, potassium tert-butoxide, triethylamine, DMAP, pyridine, panpipidine, 2,6-dimethylpyridine or a mixture of any two or more thereof, more preferably ethylenediamine; the inorganic base is preferably an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof, more preferably potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof. In some embodiments, in the method for preparing the compound of formula VIII, the base is diethylamine.

[0165] In some embodiments, in the method for preparing the compound of formula VIII, the volume ratio of the base to the organic solvent can be 0.1 - 0.5, preferably 0.2 - 0.3, and more preferably 0.2.

[0166] In some embodiments, in the method for preparing the compound of formula VIII, the organic solvent can be DMF, DMSO, tetrahydrofuran, 1,4 - dioxane, or a mixture of any two or more thereof, preferably DMF.

[0167] In some embodiments, in the method for preparing the compound of formula VIII, the temperature of the Fmoc - deprotection reaction can be the conventional temperature for such reactions in the art, for example, 10 - 40 °C, preferably 25 - 40 °C, and further preferably 25 - 30 °C.

[0168] In some embodiments, in the method for preparing the compound of formula VIII, the operation of the Fmoc - deprotection reaction can be the conventional operation for such reactions in the art. For example, it includes the following steps: stirring a mixed system of the compound of formula IX, a base, and an organic solvent to carry out the Fmoc - deprotection reaction.

[0169] In some embodiments, in the method for preparing the compound of formula VIII, the progress of the Fmoc - deprotection reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC, or NMR, etc.). Generally, the reaction end - point is when the compound of formula IX is no longer detected. The reaction time can be 1 - 24 hours, preferably 4 - 12 hours, further preferably 4 - 6 hours, and more preferably 4 hours.

[0170] In some embodiments, in the method for preparing the compound of formula VIII, after the reaction, the following post - treatment steps can further be included: performing solid - liquid separation on the reaction solution, removing the solvent from the obtained liquid phase to obtain a crude product. The post - treatment steps can further include the following steps: slurrying the crude product to obtain a solid product of the compound of formula VIII. Among them, the solvent used for slurrying can be an ether solvent, such as tetrahydrofuran, diethyl ether, 1,4 - dioxane, anisole, methyl tert - butyl ether, or a mixture of any two or more thereof, preferably methyl tert - butyl ether. The post - treatment steps can further include the following steps: recrystallizing and purifying the solid product of the compound of formula VIII obtained by slurrying. Among them, the solvent used for recrystallization can be an alcohol solvent, such as methanol, ethanol, isopropanol, or a mixture of any two or more thereof, preferably ethanol.

[0171] The method for preparing the compound of formula VIII may further include a method for preparing the compound of formula IX, which may include the following steps: coupling the compound of formula X with N-Fmoc-L-valine N-butadienyl imidate in a solvent to obtain the compound of formula IX;

[0172]

[0173] wherein, R 1 As described above.

[0174] In some embodiments, in the method for preparing the compound of formula IX, the molar ratio of N-Fmoc-L-valine N-butadienyl imidate to the compound of formula X may be 0.8 - 5, preferably 0.8 - 1.2, and more preferably 1.

[0175] In some embodiments, in the method for preparing the compound of formula IX, the solvent may be DMF, DMSO, acetonitrile, dichloromethane, dichloroethane, or a mixture of any two or more thereof, preferably dichloromethane.

[0176] In some embodiments, in the method for preparing the compound of formula IX, the temperature of the coupling reaction may be the conventional temperature for such reactions in the art, for example, 10 - 40 °C, preferably 35 - 40 °C, and more preferably 40 °C.

[0177] In some embodiments, in the method for preparing the compound of formula IX, the coupling reaction is preferably carried out under gas protection. The gas in the gas protection does not participate in the reaction, such as argon, helium, or nitrogen, or nitrogen for example.

[0178] In some embodiments, in the method for preparing the compound of formula IX, the operation of the coupling reaction may be the conventional operation for such reactions in the art, for example, including the following steps: stirring the mixed system of the compound of formula X, N-Fmoc-L-valine N-butadienyl imidate, and the solvent to carry out the coupling reaction.

[0179] In some embodiments, in the method for preparing the compound of formula IX, the progress of the coupling reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC, or NMR, etc.), and generally, the reaction end point is when the compound of formula X is no longer detected. The reaction time of the coupling reaction may be 1 - 24 hours, preferably 12 - 20 hours, more preferably 16 - 20 hours, and even more preferably 16 hours.

[0180] In some embodiments, in the method for preparing the compound of formula IX, after the coupling reaction is completed, a post-treatment step may further be included, and the post-treatment step may include: adding an alcohol solvent (such as methanol, ethanol, isopropanol or a mixture of any two or more thereof, preferably methanol) to the reaction system, followed by stirring (the temperature of stirring may be 20 - 40 °C, preferably 35 - 40 °C, more preferably 40 °C; the time of stirring may be 1 - 24 hours, preferably 4 - 12 hours, more preferably 4 - 6 hours, even more preferably 4 hours), and separating the solid in the system to obtain the compound of formula VII.

[0181] The method for preparing the compound of formula IX may further include a method for preparing the compound of formula X, which may include the following steps: performing a de-Fmoc reaction on the compound of formula XI in the presence of a base and in a solvent to obtain the compound of formula X;

[0182]

[0183] wherein, R 1 As described above.

[0184] In some embodiments, in the method for preparing the compound of formula X, the base may be a base conventional in such reactions in the art, such as an organic base, an inorganic base or a mixture thereof, preferably an organic base; wherein, the organic base is preferably diethylamine, potassium tert-butoxide, triethylamine, DMAP, pyridine, panpipidine, 2,6-dimethylpyridine or a mixture of any two or more thereof, more preferably ethylenediamine; the inorganic base is preferably an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof, more preferably potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof. In some embodiments, in the method for preparing the compound of formula X, the base is diethylamine.

[0185] In some embodiments, in the method for preparing the compound of formula X, the solvent may be DMF, DMSO, tetrahydrofuran, 1,4-dioxane or a mixture of any two or more thereof, preferably DMF.

[0186] In some embodiments, in the method for preparing the compound of formula X, the volume ratio of the base to the solvent may be 0.2 - 0.5, preferably 0.3 - 0.4, even more preferably 0.3.

[0187] In some embodiments, in the method for preparing the compound of formula X, the reaction temperature of the de-Fmoc reaction may be a conventional temperature in such reactions in the art, such as 10 - 40 °C, preferably 25 - 40 °C, more preferably 25 - 30 °C.

[0188] In some embodiments, in the method for preparing the compound of formula X, the operation of the de-Fmoc reaction can be a conventional operation for such reactions in the art, for example, including the following steps: stirring a mixed system of the compound of formula XI, a base, and a solvent to carry out the de-Fmoc reaction.

[0189] In some embodiments, in the method for preparing the compound of formula X, the progress of the de-Fmoc reaction can be monitored by conventional testing methods in the art (such as TLC, GC, HPLC, or NMR, etc.), and generally, the reaction end point is when the compound of formula XI is no longer detected. The reaction time of the reaction can be 1 - 24 hours, preferably 2 - 12 hours, more preferably 2 - 6 hours, and even more preferably 2 hours.

[0190] In some embodiments, in the method for preparing the compound of formula X, after the de-Fmoc reaction is completed, a post-treatment step can further be included. The post-treatment step can include: removing the solvent from the reaction solution, and the solid obtained by triturating the resulting residue is the compound of formula X. Among them, the solvent used for triturating can be an ether solvent, such as tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether, or a mixture of any two or more of them, and preferably methyl tert-butyl ether.

[0191] The method for preparing the compound of formula X can further include a method for preparing the compound of formula XI, which can include the following steps: reacting the compound of formula XII with an amino compound R 1 NH 2 in the presence of a base and in a solvent to carry out a coupling reaction to obtain the compound of formula XI;

[0192]

[0193] wherein, R 1 is as described above.

[0194] In some embodiments, in the method for preparing the compound of formula XI, the molar ratio of the amino compound R 1 NH 2 to the compound of formula XII can be 1.0 - 3.0, preferably 1.1 - 1.5, and more preferably 1.1.

[0195] In some embodiments, in the method for preparing the compound of formula XI, the base can be a base conventional in such reactions in the art, such as an organic base, an inorganic base or a mixture thereof, preferably an organic base; wherein, the organic base is preferably diethylamine, potassium tert-butoxide, triethylamine, DMAP, pyridine, panpipidine, 2,6-dimethylpyridine or a mixture of any two or more thereof, more preferably DMAP; the inorganic base is preferably an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof, more preferably potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof. In some embodiments, in the method for preparing the compound of formula XI, the base can be DMAP.

[0196] In some embodiments, in the method for preparing the compound of formula XI, the molar ratio of the base to the compound of formula XII can be 2-4, preferably 2.5-3.0, more preferably 2.5.

[0197] In some embodiments, in the method for preparing the compound of formula XI, the solvent can be DMF, DMSO, dichloromethane, dichloroethane, tetrahydrofuran, 1,4-dioxane or a mixture of any two or more thereof, preferably dichloromethane.

[0198] In some embodiments, in the method for preparing the compound of formula XI, the coupling reaction temperature can be a conventional temperature for such reactions in the art, such as 10-40 °C, preferably 25-40 °C, more preferably 25-30 °C.

[0199] In some embodiments, in the method for preparing the compound of formula XI, the operation of the coupling reaction can be a conventional operation for such reactions in the art, for example, including the following steps: stirring a mixed system of the compound of formula XII, the amino compound R 1 NH 2 , a base and a solvent to carry out a coupling reaction.

[0200] In some embodiments, in the method for preparing the compound of formula XI, the progress of the coupling reaction can be monitored by a conventional test method in the art (such as TLC, GC, HPLC or NMR, etc.), and generally, the reaction end point is when the compound of formula XII is no longer detected. The reaction time of the reaction can be 1-24 hours, preferably 12-20 hours, more preferably 12-16 hours, even more preferably 12 hours.

[0201] In some embodiments, in the method for preparing the compound of formula XI, after the coupling reaction is completed, a post-treatment step may further be included. The post-treatment step may include: performing solid-liquid separation on the reaction solution, and the solid obtained by solid-liquid separation (which can be washed with an organic solvent such as ether, ethyl acetate or a mixture thereof, preferably ethyl acetate after solid-liquid separation) is a part of the product of the compound of formula XI. The post-treatment step may further include: performing extraction washing on the liquid phase obtained by solid-liquid separation, and pulping the solid obtained after removing the solvent from the obtained organic phase to obtain another part of the product of the compound of formula XI. The extraction washing may use an aqueous solution of an acid, an aqueous solution of a base, water and a saturated brine solution, preferably performing extraction washing with an aqueous solution of an acid, an aqueous solution of a base, water and a saturated brine in sequence; more preferably, washing once with an aqueous solution of an acid, washing twice with an aqueous solution of a base, washing once with water and washing once with a saturated brine; the aqueous solution of the acid may be an aqueous solution of hydrochloric acid, sulfuric acid or phosphoric acid, preferably 1N hydrochloric acid, 0.5N sulfuric acid or 0.33N phosphoric acid, more preferably 1N hydrochloric acid; the aqueous solution of the base may be an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide or a mixture thereof, preferably 1N sodium hydroxide, 1N potassium hydroxide or a mixture thereof, more preferably 1N sodium hydroxide. The solvent for pulping may be dichloromethane, ethyl acetate or a mixture thereof, preferably dichloromethane; the temperature for pulping may be 10 - 40°C, preferably 25 - 40°C, more preferably 25 - 30°C.

[0202] The method for preparing the compound of formula XI may further include a method for preparing the compound of formula XII, which may include the following steps: reacting the compound of formula XIII and the compound of formula XIV in the presence of a base and in a solvent to obtain the compound of formula XII;

[0203]

[0204] In some embodiments, in the method for preparing the compound of formula XII, the molar ratio of the compound of formula XIV to the compound of formula XIII may be 3.0 - 1.2, preferably 2.0 - 1.5, more preferably 1.5.

[0205] In some embodiments, in the method for preparing the compound of formula XII, the base can be a base conventional in such reactions in the art, such as an organic base, an inorganic base or a mixture thereof, preferably an organic base; wherein, the organic base is preferably diethylamine, potassium tert-butoxide, triethylamine, DMAP, pyridine, panipidine, 2,6-dimethylpyridine or a mixture of any two or more thereof, more preferably pyridine; the inorganic base is preferably an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture thereof, more preferably potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof. In some embodiments, in the method for preparing the compound of formula XII, the base is pyridine.

[0206] In some embodiments, in the method for preparing the compound of formula XII, the molar ratio of the base to the compound of formula XIII can be 1.0 - 4.0, preferably 2.0 - 3.0, more preferably 2.0.

[0207] In some embodiments, in the method for preparing the compound of formula XII, the solvent can be DMF, DMSO, dichloromethane, dichloroethane, tetrahydrofuran, 1,4-dioxane or a mixture of any two or more thereof, preferably dichloromethane.

[0208] In some embodiments, in the method for preparing the compound of formula XII, the reaction temperature can be a conventional temperature for such reactions in the art, such as 10 - 40 °C, preferably 25 - 40 °C, more preferably 25 - 30 °C.

[0209] In some embodiments, in the method for preparing the compound of formula XII, the operation of the reaction can be a conventional operation for such reactions in the art, for example, including the following steps: adding the compound of formula XIV in batches (which can be divided into 6 - 3 batches, preferably divided into 5 - 4 batches) to a mixed system of the compound of formula XIII, the base and the solvent (the temperature of the mixed system can be controlled at 0 - 20 °C, preferably 10 - 0 °C, more preferably 0 - 5 °C) during the adding process, and stirring to carry out the reaction.

[0210] In some embodiments, in the method for preparing the compound of formula XII, the progress of the reaction can be monitored by a conventional testing method in the art (such as TLC, GC, HPLC or NMR, etc.), and generally, the reaction end point is when the compound of formula XIII is no longer detected. The reaction time of the reaction can be 1 - 24 hours, preferably 2 - 12 hours, more preferably 4 - 8 hours, and even more preferably 4 hours.

[0211] In some embodiments, in the method for preparing the compound of formula XII, a post-treatment step may further be included after the reaction is completed. The post-treatment step may include: performing solid-liquid separation on the reaction solution, and the solid obtained by the solid-liquid separation is a part of the product of the compound of formula XII. The post-treatment step may further include: performing extraction washing on the liquid phase obtained by the solid-liquid separation, and pulping the solid obtained after removing the solvent from the obtained organic phase to obtain another part of the product of the compound of formula XII. The extraction washing may use an aqueous solution of an acid, an aqueous solution of a base, water, and a saturated sodium chloride solution, preferably performing extraction washing with an aqueous solution of an acid, an aqueous solution of a base, water, and saturated sodium chloride in sequence; more preferably, washing once with an aqueous solution of an acid, washing twice with an aqueous solution of a base, washing once with water, and washing once with saturated sodium chloride; the aqueous solution of the acid may be an aqueous hydrochloric acid solution, an aqueous sulfuric acid solution, or an aqueous phosphoric acid solution, preferably 1N hydrochloric acid, 0.5N sulfuric acid, or 0.33N phosphoric acid, more preferably 1N hydrochloric acid; the aqueous solution of the base may be an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, or a mixture thereof, preferably 1N sodium hydroxide, 1N potassium hydroxide, or a mixture thereof, more preferably 1N sodium hydroxide. The solvent for the pulping may be tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether, or a mixture of any two or more thereof, preferably methyl tert-butyl ether.

[0212] The present invention also provides a compound of formula II:

[0213]

[0214] Wherein, R 1 、R 2 、R 3 and R 4 are as defined above.

[0215] In some embodiments, the compound of formula II is

[0216]

[0217] The present invention also provides a method for preparing a compound of formula II, which includes the following steps: performing a coupling reaction on a compound of formula III and N-succinimidyl 6-(maleimidyl)hexanoate in a solvent to obtain the compound of formula II;

[0218]

[0219] Wherein, R 1 、R 2 、R 3 and R 4 are as defined above.

[0220] In the preparation method of the compound of formula II, the reaction conditions can all be as described above. The preparation method of the compound of formula II may further include the preparation method of the compound of formula III described herein.

[0221] The present invention also provides a compound of formula III:

[0222]

[0223] Wherein, R 1 、R 2 、R 3 and R 4 are defined as described above.

[0224] In some embodiments, the compound of formula III is

[0225]

[0226]

[0227] The present invention also provides a preparation method of the compound of formula III, which includes the following steps: performing a reduction reaction on the compound of formula IV and a reducing agent in an organic solvent in the presence of an acid buffer to obtain the compound of formula III;

[0228]

[0229] Wherein, R 1 、R 2 、R 3 and R 4 are defined as described above.

[0230] In the preparation method of the compound of formula III, the reaction conditions can all be as described above. The preparation method of the compound of formula III may further include the preparation method of the compound of formula IV described herein.

[0231] The present invention also provides a compound of formula IV:

[0232]

[0233] Wherein, R 1 、R 2 、R 3 and R 4 are defined as described above.

[0234] In some embodiments, the compound of formula IV is

[0235]

[0236] The present invention also provides a method for preparing a compound of Formula IV, which comprises the following steps: subjecting a compound of Formula V and a compound of Formula VIa to a substitution reaction in a solvent in the presence of a base to obtain the compound of Formula IV;

[0237]

[0238] wherein R 1 , R 2 , R 3 and R 4 are as described above.

[0239] In the method for preparing the compound of Formula IV, the reaction conditions can all be as described above. The method for preparing the compound of Formula IV may further include the method for preparing the compound of Formula V and / or the compound of Formula VIa described herein.

[0240] The present invention also provides a compound represented by Formula VIa:

[0241]

[0242] wherein R 2 , R 3 and R 4 are defined as described above.

[0243] In some embodiments, the compound represented by Formula VIa is

[0244]

[0245] The present invention also provides a method for preparing a compound of Formula VIa, which comprises the following steps: subjecting a compound of Formula VIb and bromoacetic acid to a condensation reaction in the presence of a condensing agent and a base to obtain the compound of Formula VIa;

[0246]

[0247] wherein R 2 , R 3 and R 4 are defined as described above.

[0248] In the method for preparing the compound of Formula VIa, the reaction conditions can all be as described above. The method for preparing the compound of Formula VIa may further include the method for preparing the compound of Formula VIb described herein.

[0249] The present invention also provides a compound represented by Formula VIb:

[0250]

[0251] wherein R 2 , R3 and R 4 are defined as described above.

[0252] In some embodiments, the compound represented by Formula VIb is

[0253]

[0254] The present invention also provides a method for preparing a compound of Formula VIb, which may include the following steps: removing the 4-methoxytrityl group linked to the amino group in the compound of Formula VIc to obtain the compound of Formula VIb;

[0255]

[0256] wherein, R 2 、R 3 and R 4 are defined as described above.

[0257] In the method for preparing the compound of Formula VIb, the reaction conditions can all be as described above. The method for preparing the compound of Formula VIb may further include the method for preparing the compound of Formula VIc described herein.

[0258] The present invention also provides a compound represented by Formula VIc:

[0259]

[0260] wherein, R 2 、R 3 and R 4 are defined as described above.

[0261] In some embodiments, the compound represented by Formula VIc is

[0262]

[0263] The present invention also provides a method for preparing a compound of Formula VIc, which includes the following steps: performing a hydroxyl protection reaction on the compound of Formula VId and a hydroxyl protecting reagent to obtain the compound of Formula VIc;

[0264]

[0265] wherein, R 2 、R 3 and R 4 are defined as described above.

[0266] In the method for preparing the compound of Formula VIc, the reaction conditions can all be as described above. The method for preparing the compound of Formula VIc may further include the method for preparing the compound of Formula VId described herein.

[0267] The present invention also provides a compound of formula VId:

[0268]

[0269] wherein, R 2 and R 3 are as defined above.

[0270] The present invention also provides a method for preparing a compound of formula VId, which comprises the following steps:

[0271] (i) Reacting irinotecan with trimethylchlorosilane;

[0272] (ii) Reacting the reaction solution of step (i) with 4-methoxytriphenylmethyl chloride in the presence of a base to obtain the compound of formula VId;

[0273]

[0274] wherein, R 2 and R 3 are as defined above.

[0275] In the method for preparing the compound of formula VId, the reaction conditions can all be as described above.

[0276] The present invention also provides a compound having a structure as shown in formula V:

[0277]

[0278] wherein, R 1 is as defined above.

[0279] In one embodiment, the compound shown in formula V is

[0280]

[0281] The present invention also provides a method for preparing a compound of formula V, which comprises the following step: Reacting a compound of formula VII with paraformaldehyde in the presence of a base to obtain the compound of formula V;

[0282]

[0283] wherein, R 1 is as described above.

[0284] In the method for preparing the compound of formula V, the reaction conditions can all be as described above.

[0285] Definition

[0286] In the present invention, the term "C 1 -C6 "Alkyl" means a saturated straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms, especially 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc., especially methyl or ethyl.

[0287] In the present invention, the term "halogen" means fluorine, chlorine, bromine or iodine, especially fluorine or chlorine.

[0288] Table 1: Abbreviations

[0289]

[0290]

[0291] On the basis of not violating the common knowledge in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain various preferred examples of the present invention.

[0292] The reagents and raw materials used in the present invention are all commercially available.

[0293] The positive and progressive effects of the present invention are as follows: to provide a preparation method of a linker drug conjugate represented by a new formula I and an intermediate thereof. The preparation method is simple in operation, easy to control the product quality, has a high yield and is suitable for industrial production. The advantages of the preparation method of the present invention compared with the methods of Synthetic Routes 1 and 2 of WO2020259258A1 mentioned in the background art are as follows: in Synthetic Routes 1 and 2 of WO2020259258A1, the intermediate products in each step after introducing irinotecan are insoluble in most organic solvents, making their purification difficult, and thus affecting the purity of the final product; through exploration, it is found that the solubility of the intermediate compounds in each step obtained after introducing irinotecan with an R 4 protection group is significantly improved, and key intermediates with good purity can be purified by methods such as recrystallization and column purification, so that a final product meeting the requirements can be further obtained. Detailed Embodiments

[0294] The present invention will be further illustrated below by way of examples, but the present invention is not limited to the scope of the examples described herein. The experimental methods without specific conditions mentioned in the following examples are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0295] In the following examples, the mass spectrometry was performed using a Waters Acquity Xevo G2-XS QTof UPLC / MS ultra-high performance liquid chromatography high-resolution mass spectrometry combined system. 11H-NMR was performed using a Bruker AVANCE III 400 MHz nuclear magnetic resonance spectrometer or a Bruker AVANCE III HD 300 MHz nuclear magnetic resonance spectrometer, and HPLC was performed using an Agilent 1260 high performance liquid chromatograph.

[0296] In the following examples, room temperature refers to 20 - 30 °C.

[0297] Example 1: Synthesis method of Compound 1

[0298] Step 1: Synthesis of Compound 11

[0299]

[0300] At room temperature, Compound 13 (10.0 g, 32.2 mmol) and Compound 14 (4.0 g, 32.5 mmol) were dispersed in 200 mL of dichloromethane, and EEDQ (9.5 g, 38.4 mmol) was added in 3 batches. After the addition was completed, the reaction solution was continuously stirred mechanically at room temperature for 12 hours, and a large amount of white solid precipitated in the system. After monitoring by TLC that the raw materials had completely reacted, the reaction solution was directly filtered by suction, and the filter cake was dried to obtain white solid Compound 11 (11.0 g, yield 82%).

[0301] MS: m / z = 417.2 (M + H);

[0302] 1 1H NMR (400 MHz, DMSO-d 6 ) δ ppm 9.95 (s, 1H), 7.88 (t, J = 9.9 Hz, 2H), 7.80 - 7.65 (m, 3H), 7.55 (t, J = 7.7 Hz, 2H), 7.46 - 7.19 (m, 6H), 5.20 - 5.02 (m, 1H), 4.43 (t, J = 7.7 Hz, 2H), 4.32 - 4.06 (m, 4H), 1.41 - 1.21 (m, 3H).

[0303] Step 2: Synthesis of Compound 10

[0304]

[0305] At room temperature, compound 11 (11.0 g, 26.4 mmol) was dispersed in 200 mL of dichloromethane, and pyridine (4.2 mL, 52.8 mmol) was added. The resulting mixture was cooled to 0 °C in an ice bath, and p-nitrophenyl chloroformate (4 times, 8.0 g, 39.6 mmol) was added portionwise under the condition of keeping the ice bath temperature. After the addition was completed, the resulting reaction solution was stirred at room temperature for 4 hours. After monitoring by TLC that the raw materials had completely reacted, the reaction solution was filtered by suction, the filter cake was collected and dried to obtain the first batch of solid; the filtrate was washed successively with 1 N hydrochloric acid, 1 N sodium hydroxide (twice), water and saturated brine, concentrated after drying, slurried with methyl tert-butyl ether for 1 hour and then filtered, the filter cake was collected and dried to obtain the second batch of solid. The two batches of solids were combined to obtain pale yellow solid compound 10 (12.0 g, yield 78%).

[0306] Step 3: Synthesis of compound 9

[0307]

[0308] At room temperature, compound 10 (12.0 g, 20.6 mmol) and methylsulfonylethylamine hydrochloride (3.6 g, 22.6 mmol, 1.1 eq) were dispersed in 200 mL of dichloromethane, and DMAP (6.3 g, 51.6 mmol) was added in 3 portions. The resulting reaction solution was stirred at room temperature for 12 hours, and a large amount of pale yellow solid precipitated. After monitoring by TLC that the raw materials had completely reacted, it was filtered by suction, the filter cake was washed twice with ethyl acetate (100 mL each) and then dried to obtain the first batch of white solid, 7.6 g. The filtrate was concentrated by rotary evaporation, dissolved in 150 mL of ethyl acetate, and then washed successively with 1 N hydrochloric acid (50 mL), 1 N sodium hydroxide (twice, 50 mL each), water and saturated brine (100 mL), concentrated after drying, slurried with dichloromethane (20 mL), filtered and dried to obtain the second batch of white solid, 2.0 g. The two batches of solids were combined to obtain white solid compound 9 (9.6 g, yield 82%).

[0309] MS: m / z = 566.2 (M+H);

[0310] 1 H-NMR (400 MHz, DMSO-d 6 ) δ ppm 10.04 (s, 1H), 7.88 (t, J = 10.8 Hz, 2H), 7.79 - 7.66 (m, 3H), 7.59 (d, J = 8.3 Hz, 2H), 7.51 - 7.22 (m, 6H), 4.97 (s, 2H), 4.37 - 4.05 (m, 4H), 3.41 (dd, J = 12.8, 6.6 Hz, 2H), 3.30 - 3.18 (m, 2H), 2.99 (s, 3H), 1.31 (d, J = 7.1 Hz, 3H).

[0311] Step 4: Synthesis of Compound 8

[0312]

[0313] At room temperature, dissolve Compound 9 (9.6 g, 16.9 mmol) in 50 mL of DMF, add 15 mL of diethylamine, and continue to stir the resulting mixture at room temperature for 2 hours. Monitor the reaction by TLC until the raw materials are completely reacted. Directly concentrate the reaction solution to remove the solvent, and slurry the resulting residue with methyl tert-butyl ether (50 mL) to obtain white solid Compound 8 (5.2 g, yield 89%).

[0314] MS: m / z = 344.1 (M+H);

[0315] 1 1H-NMR (400 MHz, DMSO-d 6 ) δ ppm 7.63 (d, J = 8.5 Hz, 2H), 7.45 (t, J = 5.6 Hz, 1H), 7.28 (d, J = 8.4 Hz, 2H), 4.97 (s, 2H), 3.41 (qd, J = 7.0, 3.2 Hz, 3H), 3.29 - 3.18 (m, 2H), 2.99 (s, 3H), 1.20 (d, J = 6.9 Hz, 3H).

[0316] Step 5: Synthesis of Compound 7

[0317]

[0318] At room temperature, disperse N-Fmoc-L-valine N-butadienamine imidate (5.1 g, 11.7 mmol) and amino Compound 8 (4.0 g, 11.7 mmol) in 100 mL of DCM. Under nitrogen protection, stir the resulting reaction solution at 40 °C overnight, and there is always a white insoluble substance in the system. Then add 5 mL of methanol to the reaction system and continue to stir at 40 °C for 4 hours. Filter the resulting reaction solution, collect the filter cake and dry it to obtain Compound 7 directly for the next step.

[0319] MS: m / z = 665.3 (M+H);

[0320] 1 1H-NMR (400 MHz, DMSO-d 6)δ ppm 10.07 (d, J = 34.2 Hz, 1H), 8.16 (t, J = 23.9 Hz, 1H), 7.89 (d, J = 7.5 Hz, 2H), 7.80 - 7.69 (m, 2H), 7.58 (d, J = 8.4 Hz, 2H), 7.52 - 7.37 (m, 3H), 7.31 (dd, J = 17.6, 8.0 Hz, 4H), 4.97 (s, 2H), 4.42 (p, J = 6.8 Hz, 1H), 4.34 - 4.17 (m, 3H), 3.98 - 3.83 (m, 1H), 3.41 (dd, J = 13.3 Hz, 2H), 3.29 - 3.19 (m, 2H), 2.99 (s, 3H), 1.99 (dq, J = 13.5 Hz, 1H), 1.31 (d, J = 7.1 Hz, 3H), 1.01 - 0.74 (m, 6H).

[0321] Step 6: Synthesis of Compound 6

[0322]

[0323] At room temperature, dissolve the compound 7 obtained in Step 5 in 50 mL of DMF, add 10 mL of diethylamine, and continue to stir the resulting mixture at room temperature for 4 hours. Monitor the reaction by TLC until the raw materials are completely reacted. At this time, there are white insoluble impurities in the reaction solution. Filter to remove the impurities, rotary evaporate the obtained filtrate with an oil pump, and stir and triturate the obtained pale yellow oil with methyl tert-butyl ether (50 mL) for about 2 hours, then filter to obtain a white solid. The obtained white solid is purified by recrystallization with ethanol to obtain white solid compound 6 (5.0 g, the two-step yield is 97%).

[0324] MS: m / z = 443.2 (M + H).

[0325] Step 7: Synthesis of Compound 5

[0326]

[0327] At room temperature, compound 6 (5.0 g, 11.3 mmol) was dispersed in 50 mL of methanol, 10 mL of dichloromethane and 25 mL of water, and potassium carbonate (3.1 g, 22.6 mmol) and copper sulfate pentahydrate (0.3 g, 1.2 mmol) were added. After the resulting mixture became clear upon stirring, 1H-imidazole-1-sulfonyl azide hydrochloride (CAS: 952234-36-5, 2.4 g, 11.5 mmol) was added, and the resulting reaction solution was stirred at room temperature overnight. After monitoring by TLC that the raw materials had completely reacted, 25 mL of water was added, and most of the methanol was removed under reduced pressure. The resulting mixture was extracted twice with dichloromethane (50 mL each). After the organic phases were combined, washed with saturated brine, dried, and recrystallized from 40 mL of ethanol and 0.3 g of activated carbon, white solid compound 5 (3.3 g, yield 62%) was obtained. MS: m / z = 469.2 (M+H).

[0328] Step 8: Synthesis of compound 4

[0329]

[0330] Compound 5 (3.3 g, 6.0 mmol) synthesized according to the method of step 7, paraformaldehyde (271.0 mg, calculated as formaldehyde: 9.0 mmol), and sodium bicarbonate (705.7 mg, 8.4 mmol) were added to a mixed solution of 50 mL of 1,4-dioxane and 10 mL of water. The resulting mixture was stirred at room temperature for 24 hours. After monitoring by TLC that the raw materials had completely reacted, 30 mL of water and 60 mL of dichloromethane were added, stirred, allowed to stand for phase separation, and the solvent was evaporated under reduced pressure from the organic phase and then vacuumed on a high vacuum pump for 2 hours to obtain a foamy solid compound 4 (3.3 g) (directly used for the next step).

[0331] Step 9a: Synthesis of compound 3a

[0332]

[0333] All of the crude product of Compound 4 (3.3 g, 6.6 mmol) obtained in Step 8 was dissolved in 25 mL of ultradry 1,4-dioxane, and then Compound Dxd-a (4.0 g, 6.6 mmol, synthesized according to the method of Example 2) and sodium methoxide (357.6 mg, 9.9 mmol) were added thereto. The resulting mixture was heated to 60 °C and stirred for 2 hours. The solvent of the resulting reaction solution was distilled off under reduced pressure. The obtained crude product was dissolved in 100 mL of dichloromethane, and then the crude product solution was washed successively with 0.1 mol / L dilute hydrochloric acid (100 mL), water (100 mL), and saturated brine (100 mL). The obtained organic phase was dried over anhydrous sodium sulfate overnight. After the solvent of the dried solution was distilled off, it was subjected to silica gel column chromatography and eluted with dichloromethane / methanol = 60:1 - 10:1 to obtain Compound 3a (6.7 g, directly used for the next step).

[0334] Step 9b: Synthesis of Compound 3b

[0335]

[0336] All of the crude product of another batch of Compound 4 (3.3 g, 6.6 mmol) obtained in Step 8 was dissolved in dry dichloromethane (150 mL), and then Compound Dxd-b (5.3 g, 6.6 mmol, synthesized according to the method of Example 3) was added. The reaction system was purged with nitrogen three times and cooled to 0 - 5 °C in an ice bath, and then sodium methoxide (357.6 mg, 9.9 mmol) was slowly added in portions. The addition was completed after 2 hours. The resulting mixture was stirred at 0 - 5 °C for another 4 - 5 hours, and the reaction was monitored by TLC until completion. The resulting reaction solution was washed with saturated brine (three times, 50 mL each), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain the crude product of Compound 3b (8.0 g, directly used for the next step).

[0337] Step 10a: Synthesis of Compound 2a

[0338]

[0339] Dissolve the compound 3a (7.1 g) obtained in step 9a in 35 mL of tetrahydrofuran, then add 50 mL of tetrahydrofuran and acetic acid buffer solution with pH 5.0 (125 mL, 12.5 mmol), and then add a tetrahydrofuran solution of 1 M trimethylphosphine (7.7 mL, 7.7 mmol). The resulting mixture was stirred at 0 - 5 °C for 2 hours. After the reaction was completed, 200 mL of saturated brine was added to the resulting reaction solution, and then extracted with 150 mL of dichloromethane. The obtained organic phase was dried over anhydrous sodium sulfate overnight and then the solvent was evaporated under reduced pressure. The obtained crude product was subjected to silica gel column chromatography and eluted with dichloromethane / methanol 20:1 - 10:1 to obtain compound 2a (3.7 g, purity 97%, yield 53% based on Dxd-a).

[0340] MS: m / z = 990.4 (M + H).

[0341] Step 10b: Synthesis of compound 2b

[0342]

[0343] Dissolve the compound 3b (8.5 g) obtained in step 9b in 35 mL of tetrahydrofuran, then add 120 mL of tetrahydrofuran and acetic acid buffer solution with pH 5.0 (125 mL, 12.5 mmol), and then add a tetrahydrofuran solution of 1 M trimethylphosphine (7.7 mL, 7.7 mmol). The resulting mixture was stirred at 0 - 5 °C for 2 hours. After the reaction was completed, 200 mL of saturated brine was added to the resulting reaction solution, and then extracted with 150 mL of dichloromethane. The obtained organic phase was dried over anhydrous sodium sulfate overnight and then the solvent was evaporated under reduced pressure. The obtained crude product was subjected to silica gel column chromatography and eluted with dichloromethane / methanol 20:1 - 10:1 to obtain compound 2b (4.7 g, purity 97%, yield 56% based on Dxd-b).

[0344] MS: m / z = 1186.5 (M + H).

[0345] Step 11a: Synthesis of compound 1a

[0346]

[0347] Mix compound 2a (3.7 g, 3.7 mmol) with compound EMCS (commercially available, 0.8 g, 3.7 mmol) and dissolve them in 20 mL of dichloromethane. The resulting mixture was stirred at 40 °C overnight. After the reaction was completed, the solvent of the resulting reaction solution was evaporated under reduced pressure. The obtained residue was subjected to silica gel column chromatography and eluted with dichloromethane / methanol = 50:1 - 15:1 to obtain compound 1a (2.8 g, yield 64%).

[0348] MS: m / z = 1183.4 (M + H);

[0349] 1 H NMR (500 MHz, CDCl 3 ) δ 9.22 (s, 1H), 7.61 (d, J = 9.2 Hz, 1H), 7.59 - 7.53 (m, 3H), 7.52 (s, 1H), 7.44 (d, J = 8.4 Hz, 1H), 7.36 - 7.30 (m, 3H), 7.19 (t, J = 1.0 Hz, 1H), 6.71 (s, 2H), 5.13 (s, 1H), 5.13 - 5.07 (m, 3H), 5.05 (d, J = 9.5 Hz, 1H), 4.91 - 4.82 (m, 3H), 4.76 (dd, J = 12.5, 1.1 Hz, 1H), 4.57 (dd, J = 8.8, 6.4 Hz, 1H), 4.46 (dq, J = 8.4, 5.7 Hz, 1H), 4.15 - 4.09 (m, 2H), 3.72 - 3.55 (m, 4H), 3.25 (td, J = 8.2, 1.6 Hz, 2H), 3.03 (s, 3H), 2.95 (ddd, J = 12.3, 8.6, 5.9 Hz, 1H), 2.84 (ddd, J = 12.5, 8.4, 5.9 Hz, 1H), 2.26 (s, 3H), 2.24 - 2.17 (m, 3H), 2.17 - 2.06 (m, 6H), 2.00 (dddd, J = 12.3 Hz, 1H), 1.69 (p, J = 6.2 Hz, 2H), 1.55 - 1.45 (m, 2H), 1.41 - 1.37 (m, 1H), 1.37 - 1.32 (m, 4H), 1.08 - 1.01 (m, 3H), 0.89 (dd, J = 6.5, 2.1 Hz, 6H).

[0350] Step 11b: Synthesis of Compound 1b

[0351]

[0352] Compound 2b (4.7 g, 4.0 mmol) was mixed with compound EMCS (commercially available, 0.8 g, 4.0 mmol) and dissolved in 60 mL of dichloromethane. The resulting mixture was stirred overnight at 40 °C. After the reaction was completed, the solvent of the resulting reaction solution was evaporated under reduced pressure. The obtained residue was subjected to silica gel column chromatography (eluent: dichloromethane / methanol = 50:1 - 15:1) to obtain compound 1b (3.8 g, yield 68%).

[0353] MS: m / z = 1379.6 (M + H);

[0354] 1 H NMR (500 MHz, CDCl 3)δ9.22(s,1H),7.66 - 7.58(m,5H),7.58 - 7.53(m,2H),7.53(d,J=8.8Hz,1H),7.44(d,J=8.4Hz,1H),7.41 - 7.30(m,9H),7.18(t,J=1.0Hz,1H),6.71(s,1H),5.15 - 5.03(m,6H),4.91 - 4.83(m,3H),4.57(dd,J=8.8,6.4Hz,1H),4.42(dq,J=8.6,5.7Hz,1H),4.13(d,J=4.0Hz,2H),3.72 - 3.62(m,2H),3.65 - 3.55(m,2H),3.25(td,J=8.2,1.6Hz,2H),3.03(s,2H),2.95(ddd,J=12.4,8.6,5.9Hz,1H),2.84(ddd,J=12.4,8.6,5.9Hz,1H),2.27 - 2.13(m,4H),2.03 - 1.86(m,3H),1.69(p,J=6.2Hz,2H),1.55 - 1.45(m,2H),1.41 - 1.32(m,5H),1.07 - 0.98(m,9H),0.89(dd,J=6.5,2.1Hz,6H).

[0355] Step 12a: Preparation of Compound 1 starting from Compound 1a

[0356]

[0357] In a 250 mL three - necked flask, dissolve Compound 1a (2.8 g, 2.4 mmol) in a mixed solvent of methanol and dichloromethane (75 mL, volume ratio 1:1). After replacing the reaction system in the three - necked flask with nitrogen three times, under nitrogen protection, cool it to 0 °C with an ice bath. Slowly add a solution of acetyl chloride (0.1 g, 1.2 mmol) dissolved in a mixed solvent of methanol and dichloromethane (5 mL, volume ratio 1:1) to the reaction system, maintaining the temperature of the reaction system at 0 - 5 °C during the dropping process; after the dropping is complete, remove the cooling device and allow the reaction system to return to room temperature and then continue stirring for 2 - 3 hours. Monitor the reaction by TLC until completion. Wash the resulting reaction solution with an aqueous sodium bicarbonate solution of pH 7 - 8 (twice, 50 mL each) and saturated brine (once, 50 mL), then dry it over anhydrous sodium sulfate and filter. Finally, concentrate the residue under reduced pressure and obtain Compound 1 (1.70 g, yield 62%) by silica gel column chromatography (eluent: dichloromethane / methanol = 30:1 - 15:1).

[0358] MS: m / z=1141.4(M + H);

[0359] 1 1H NMR (500 MHz, CDCl 3 ) δ 9.22 (s, 1H), 7.61 (d, J = 9.2 Hz, 1H), 7.59 - 7.53 (m, 2H), 7.53 (d, J = 8.8 Hz, 1H), 7.44 (d, J = 8.4 Hz, 1H), 7.36 - 7.30 (m, 3H), 7.24 (t, J = 1.0 Hz, 1H), 6.71 (s, 1H), 5.23 (dd, J = 12.4, 1.1 Hz, 1H), 5.15 - 5.10 (m, 3H), 5.06 (d, J = 9.5 Hz, 1H), 4.91 - 4.83 (m, 3H), 4.77 - 4.70 (m, 2H), 4.57 (dd, J = 8.8, 6.4 Hz, 1H), 4.46 (dq, J = 8.4, 5.7 Hz, 1H), 4.13 (d, J = 4.0 Hz, 2H), 3.72 - 3.55 (m, 4H), 3.25 (td, J = 8.2, 1.6 Hz, 2H), 3.03 (s, 2H), 2.95 (ddd, J = 12.5, 8.6, 6.0 Hz, 1H), 2.84 (ddd, J = 12.4, 8.6, 5.9 Hz, 1H), 2.27 - 2.13 (m, 4H), 2.01 - 1.86 (m, 2H), 1.79 (dq, J = 13.7, 8.0 Hz, 1H), 1.69 (p, J = 6.2 Hz, 2H), 1.55 - 1.45 (m, 2H), 1.41 - 1.34 (m, 2H), 1.34 (d, J = 5.7 Hz, 3H), 0.97 (t, J = 8.0 Hz, 3H), 0.89 (dd, J = 6.5, 2.1 Hz, 6H).

[0360] Step 12b: Preparation of Compound 1 from Compound 1b

[0361]

[0362] Compound 1b (3.8 g, 2.8 mmol) was added to a mixed solution of dichloromethane and methanol (30 mL, volume ratio 20:1). Then, a mixed solution of tert-butylammonium fluoride (1.1 g, 4.2 mmol, dissolved in 5 mL of a mixed solvent of dichloromethane and methanol with a volume ratio of 20:1) and acetic acid (0.3 g, 4.2 mmol) was slowly added dropwise to the reaction system. As the reaction proceeded, a white solid began to precipitate in the reaction system. The resulting mixture was stirred overnight at room temperature. TLC detection showed that the reaction was complete. The reaction solution was filtered, and the obtained filter cake was washed with dichloromethane (twice, with amounts of 20 mL and 10 mL respectively), and then the residual solvent was removed under reduced pressure to obtain white solid Compound 1 (3.0 g, purity 98%, yield 95%).

[0363] MS: m / z = 1141.4 (M+H);

[0364] 1 H NMR (500 MHz, CDCl 3 ) δ 9.22 (s, 1H), 7.61 (d, J = 9.2 Hz, 1H), 7.59 - 7.53 (m, 2H), 7.53 (d, J = 8.8 Hz, 1H), 7.44 (d, J = 8.4 Hz, 1H), 7.36 - 7.30 (m, 3H), 7.24 (t, J = 1.0 Hz, 1H), 6.71 (s, 1H), 5.23 (dd, J = 12.4, 1.1 Hz, 1H), 5.15 - 5.10 (m, 3H), 5.06 (d, J = 9.5 Hz, 1H), 4.91 - 4.83 (m, 3H), 4.77 - 4.70 (m, 2H), 4.57 (dd, J = 8.8, 6.4 Hz, 1H), 4.46 (dq, J = 8.4, 5.7 Hz, 1H), 4.13 (d, J = 4.0 Hz, 2H), 3.72 - 3.55 (m, 4H), 3.25 (td, J = 8.2, 1.6 Hz, 2H), 3.03 (s, 2H), 2.95 (ddd, J = 12.5, 8.6, 6.0 Hz, 1H), 2.84 (ddd, J = 12.4, 8.6, 5.9 Hz, 1H), 2.27 - 2.13 (m, 4H), 2.01 - 1.86 (m, 2H), 1.79 (dq, J = 13.7, 8.0 Hz, 1H), 1.69 (p, J = 6.2 Hz, 2H), 1.55 - 1.45 (m, 2H), 1.41 - 1.34 (m, 2H), 1.34 (d, J = 5.7 Hz, 3H), 0.97 (t, J = 8.0 Hz, 3H), 0.89 (dd, J = 6.5, 2.1 Hz, 6H).

[0365] Example 2: Synthesis of Compound Dxd-a

[0366]

[0367] Step 1: Synthesis of Intermediate 17

[0368] Into a 250 mL three-necked flask, irinotecan (4.4 g, 10.0 mmol) and dichloromethane (66 mL) were added, and then trimethylchlorosilane (1.6 mL, 12.0 mmol) was added. The resulting milky mixture was heated to 45 °C and refluxed for 1 hour. TLC monitoring showed that irinotecan had been completely reacted. Then the reaction solution was cooled to 0 °C, and then N,N-diisopropylethylamine (5.0 mL, 30.0 mmol) and 4-methoxytriphenylmethyl chloride (3.7 g, 12.0 mmol) were added. The resulting mixture was stirred overnight at room temperature, and TLC monitoring showed that the reaction was complete. The resulting reaction solution was washed with pH = 5 sodium acetate buffer solution (2 times, 20 mL each) and saturated brine (2 times, 20 mL each). The resulting organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated to obtain the crude product of intermediate 17 (6.0 g, crude yield 85%).

[0369] MS: m / z = 708.3 (M+H);

[0370] 1 H NMR (500 MHz, CDCl 3 ) δ 7.34 - 7.26 (m, 11H), 7.24 (t, J = 1.0 Hz, 1H), 7.16 - 7.10 (m, 2H), 6.89 - 6.84 (m, 2H), 5.24 (dd, J = 12.4, 1.0 Hz, 1H), 5.11 (d, J = 9.5 Hz, 1H), 5.04 (d, J = 9.5 Hz, 1H), 4.88 (dt, J = 8.6, 4.4 Hz, 1H), 4.75 (s, 1H), 4.70 (dd, J = 12.3, 1.0 Hz, 1H), 3.85 (d, J = 8.2 Hz, 1H), 3.78 (s, 2H), 2.93 (dt, J = 12.5, 6.3 Hz, 1H), 2.82 (dt, J = 12.5, 6.4 Hz, 1H), 2.08 (td, J = 6.3, 4.4 Hz, 2H), 2.04 - 1.89 (m, 2H), 0.97 (t, J = 8.0 Hz, 3H).

[0371] Step 2: Synthesis of intermediate 16a

[0372] Add intermediate 17 (2.4 g, 3.0 mmol), dichloromethane (36 mL), 4-dimethylaminopyridine (1.3 g, 10.0 mmol) and triethylamine (0.7 mL, 5.0 mmol) into a 100 mL three-necked flask. The resulting reaction system was cooled to 0 °C in an ice bath and purged with nitrogen three times. A dichloromethane solution (12 mL) of acetic anhydride (0.4 g, 4.0 mmol) was slowly added dropwise to the reaction system, and the temperature of the system was maintained at 0 - 5 °C during the addition. After the addition was completed, the ice bath was removed to allow the temperature of the reaction solution to rise to room temperature. The resulting reaction solution was stirred for another 3 hours, and the reaction was monitored by TLC until completion. The reaction solution was added to a sodium acetate / acetic acid buffer solution with pH = 5.0 (50 mL), and the resulting mixture was extracted with dichloromethane (100 mL). The organic phase was washed with saturated brine (three times, 50 mL each time), dried over anhydrous sodium sulfate and stirred for 0.5 hour, and then filtered and concentrated to obtain solid intermediate 16a (1.7 g, yield 75%).

[0373] MS: m / z = 750.3 (M + H);

[0374] 1 H NMR (500 MHz, CDCl 3 ) δ 7.33 - 7.26 (m, 10H), 7.19 (t, J = 1.0 Hz, 1H), 7.16 - 7.10 (m, 2H), 6.89 - 6.84 (m, 2H), 5.14 - 5.08 (m, 2H), 5.05 (d, J = 9.3 Hz, 1H), 4.88 (dt, J = 8.6, 4.4 Hz, 1H), 4.74 (dd, J = 12.5, 0.9 Hz, 1H), 3.85 (d, J = 8.2 Hz, 1H), 3.78 (s, 2H), 2.93 (dt, J = 12.5, 6.3 Hz, 1H), 2.82 (dt, J = 12.5, 6.4 Hz, 1H), 2.26 (s, 2H), 2.17 (dq, J = 14.1, 8.3 Hz, 1H), 2.13 - 2.07 (m, 1H), 2.10 - 2.04 (m, 2H), 1.05 (t, J = 8.3 Hz, 3H).

[0375] Step 3: Synthesis of intermediate 15a

[0376] At room temperature, intermediate 16a (1.7 g, 2.3 mmol) and dichloromethane (40 mL) were added to a three-necked flask. After dissolution, triethylsilane (0.7 g, 5.8 mmol) was added. The resulting mixture was cooled to -5 - 5 °C, purged with argon three times, and the internal temperature of the reaction solution was maintained at -5 - 5 °C under argon protection. Stirring was continued for 1 - 1.5 hours, and the reaction was monitored by TLC until completion. Methyl tert-butyl ether (80 mL) was added dropwise to the resulting reaction solution while maintaining the internal temperature at 0 - 5 °C. After the addition, the supernatant was decanted. The resulting viscous solid was stirred and dissolved in dichloromethane (40 mL), and methyl tert-butyl ether (80 mL) was added dropwise while maintaining the internal temperature at 0 - 10 °C. A solid precipitated during the addition, and the solid was collected by filtration to obtain intermediate 15a (0.8 g, crude yield 75%). MS: m / z = 478.2 (M+H);

[0377] 1 H NMR(500MHz,CDCl 3 )δ7.32(d,J=7.9Hz,1H),7.19(t,J=1.0Hz,1H),5.13 - 5.07(m,2H),5.05(d,J=9.5Hz,1H),4.76(dd,J=12.5,1.1Hz,1H),4.26(tdd,J=6.8Hz,1H),2.93(ddd,J=12.4Hz,1H),2.85(ddd,J=12.4Hz,1H),2.45(t,J=6.9Hz,1H),2.34(t,J=6.9Hz,1H),2.26(s,2H),2.19 - 2.00(m,3H),1.90(ddt,J=12.3Hz,1H),1.05(t,J=8.3Hz,3H).

[0378] Step 4: Synthesis of Dxd-a

[0379] To a 100 mL three-necked flask, intermediate 15a (0.8 g, 2.0 mmol), bromoacetic acid (416.8 mg, 3.0 mmol) and 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride (1.2 g, 4.0 mmol) were added, and then dichloromethane (30 mL) was added. The resulting reaction system was purged with nitrogen three times and then N,N-diisopropylethylamine (0.7 g, 5.0 mmol) was added. The resulting mixture was stirred at room temperature for 13 hours, and the reaction was monitored by TLC until completion. The resulting reaction solution was concentrated and purified by column chromatography (using dichloromethane:methanol = 50:1 as the eluent) to obtain compound Dxd-a (921.5 g, yield 77%). MS: m / z = 598.2 (M+H);

[0380] 1 H NMR(500MHz,CDCl3 )δ 7.62 (d, J = 9.3 Hz, 1H), 7.32 (d, J = 7.9 Hz, 1H), 7.19 (t, J = 1.0 Hz, 1H), 5.15 - 5.08 (m, 2H), 5.05 (d, J = 9.5 Hz, 1H), 4.74 (dd, J = 12.4 Hz, 1H), 3.96 (d, J = 5.5 Hz, 2H), 3.86 - 3.80 (m, 1H), 2.95 (ddd, J = 12.3 Hz, 1H), 2.84 (ddd, J = 12.5 Hz, 1H), 2.26 (s, 2H), 2.22 - 2.10 (m, 2H), 2.19 (s, 3H), 2.13 - 2.04 (m, 1H), 2.00 (dddd, J = 12.3 Hz, 1H), 1.05 (t, J = 8.3 Hz, 3H).

[0381] Example 3: Synthesis of Compound Dxd-b

[0382]

[0383] Step 1: Synthesis of Intermediate 16b

[0384] Add Intermediate 17 (3.5 g, 5.0 mmol), N,N-dimethylformamide (70 mL) and N,N-diisopropylethylamine (1.1 g, 10.0 mmol) into a 250 mL three-necked flask. Cool the resulting reaction system to 3 °C and displace it with nitrogen three times. Then, add tert-butyldiphenylchlorosilane (1.5 g, 5.5 mmol) dropwise to the reaction system, keeping the internal temperature at 0 - 10 °C during the addition. After the addition, warm the reaction solution to room temperature and continue stirring for 3 hours. Monitor the reaction completion by TLC. Pour the resulting reaction solution into ice water (50 mL), and then extract it with ethyl acetate (100 mL). Wash the obtained organic phase with saturated brine (three times, 80 mL each), dry it over anhydrous sodium sulfate, stir, filter, and concentrate to obtain solid Intermediate 16b (4.4 g, yield 92%).

[0385] MS: m / z = 946.4 (M + H);

[0386] 1 H NMR (500 MHz, CDCl 3)δ 7.66 - 7.58 (m, 4H), 7.41 - 7.34 (m, 6H), 7.37 - 7.26 (m, 10H), 7.18 (t, J = 1.0 Hz, 1H), 7.16 - 7.10 (m, 2H), 6.89 - 6.84 (m, 2H), 5.15 - 5.02 (m, 4H), 4.88 (ddd, J = 8.6, 5.8, 3.0 Hz, 1H), 3.85 (d, J = 8.2 Hz, 1H), 3.78 (s, 2H), 2.94 (ddd, J = 12.6 Hz, 1H), 2.81 (ddd, J = 12.4 Hz, 1H), 2.19 (dddd, J = 12.5 Hz, 1H), 2.03 - 1.87 (m, 3H), 1.07 - 0.98 (m, 9H).

[0387] Step 2: Synthesis of Intermediate 15b

[0388] At room temperature, add Intermediate 16b (3.3 g, 4.7 mmol) and dichloromethane (60 mL) into a three-necked flask, then add triethylsilane (0.7 g, 6.1 mmol). Cool the resulting reaction system to -5 - 5 °C, displace with argon three times, and then continue stirring for 1 - 1.5 hours while maintaining the internal temperature at -5 - 5 °C under argon protection. Monitor the reaction completion by TLC. Dropwise add methyl tert-butyl ether (120 mL) to the resulting reaction solution while maintaining the internal temperature at 0 - 5 °C. After the addition, pour off the supernatant. Dissolve the resulting viscous solid with dichloromethane (60 mL) while maintaining the internal temperature at 0 - 10 °C. Dropwise add methyl tert-butyl ether (120 mL). Solids precipitate during the addition. Filter and collect the solids to obtain Intermediate 15b (2.5 g, crude yield 78%).

[0389] MS: m / z = 674.3 (M + H).

[0390] Step 3: Synthesis of Compound Dxd-b

[0391] Add Intermediate 15b (1.3 g, 2.0 mmol), bromoacetic acid (416.8 mg, 3.0 mmol) and 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride (1.2 g, 4.0 mmol) into a 250 mL three-necked flask. Then add DCM (55 mL). Displace the resulting reaction system with nitrogen three times and then add N,N-diisopropylethylamine (0.7 g, 5.0 mmol). Stir the resulting mixture at room temperature for 13 hours and monitor the reaction completion by TLC. Concentrate the resulting reaction solution and purify it by column chromatography (using DCM:MeOH = 50:1 as the eluent) to obtain Compound Dxd-b (1.2 g, yield 73%).

[0392] MS: m / z = 794.3 (M + H);

[0393] 1 H NMR(500MHz,CDCl 3 ) δ 7.65 - 7.58(m,5H), 7.41 - 7.30(m,7H), 7.18(t, J = 1.0Hz,1H), 5.15 - 5.09(m,2H), 5.11 - 5.03(m,2H), 4.89(ddd, J = 9.3Hz,1H), 3.83(t, J = 5.5Hz,1H), 2.95(ddd, J = 12.4Hz,1H), 2.84(ddd, J = 12.5Hz,1H), 2.39(d, J = 5.5Hz,2H), 2.21(d, J = 5.8Hz,2H), 2.2(s,3H), 2.18(dddd, J = 12.3Hz,1H), 2.03 - 1.86(m,3H), 1.07 - 0.98(m,10H).

[0394] Example 4: Comparison of the product purity of several process routes:

[0395] The final product of Compound 1 obtained according to Route 1 (i.e., the synthesis of LE14 in Example 7) and Route 2 (i.e., the synthesis of LE14 in Example 10) disclosed in WO2020259258A1 and the final product of Compound 1 obtained by the synthesis method of Steps 12a and 12b of Example 1 of the present invention were compared for purity by high performance liquid chromatography. The results are shown in Table 3 below.

[0396] The liquid phase conditions used: Phase A is 0.1% formic acid aqueous solution, Phase B is 0.1% formic acid acetonitrile solution, the detection wavelength is 370 nm, the instrument is Agilent 1260, and the chromatographic column is ZORBAX Eclipse Plus C18, 3.5 μm, 4.6×150 mm. The gradient settings are as shown in Table 2 below.

[0397] Table 2. Mobile phase gradient settings

[0398] Time (min) Mobile phase A % Mobile phase B % 0.00 80.0 20.0 10.00 60.0 40.0 25.00 60.0 40.0 35.00 30.0 70.0 41.00 30.0 70.0 41.10 80.0 20.0 43.00 80.0 20.0

[0399] Table 3. Comparison data of the purity of final products of different process routes

[0400] Route 1 Route 2 Step 12a of Example 1 Step 12b of Example 1 Final product purity 95％ 96％ 97％ 98％ Maximum single impurity 3％ 2％ ＜1％ ＜1.5％

Claims

1. A method for preparing a compound of formula IV, comprising the following steps: subjecting a compound of formula V and a compound of formula VIa to a substitution reaction in a solvent in the presence of a base to obtain the compound of formula IV; Wherein, R 1 is C 1 to C 6 alkyl, one or more R 1-3 S(O) 2 -substituted C 1 to C 6 alkyl, or one or more N(R 1-1 )(R 1-2 )-substituted C 1 to C 6 alkyl; R 2 and R 3 each independently is C 1 ~C 6 alkyl, C 1 ~C 6 alkyl substituted with one or more halogens, or halogen; R 1-1 , R 1-2 and R 1-3 Each independently is C 1 ~C 4 alkyl; R 4 is a hydroxyl protecting group.

2. The preparation method according to claim 1, characterized in that, R 1 is an R 1-3 S(O) 2 -substituted C 1 ~C 6 alkyl; and / or, R 2 is C 1 ~C 6 alkyl; and / or, R 3 is a halogen; and / or, R 1-3 is C 1 ~C 4 alkyl; and / or, the hydroxyl protecting group is an ester protecting group or a silyl ether protecting group.

3. The preparation method according to claim 2, characterized in that, R 1 is methylsulfonyl ethyl; and / or, R 2 is methyl; and / or, R 3 is fluorine; and / or, R 1-3 is methyl.

4. The preparation method according to claim 1, characterized in that, in the preparation method of the compound of formula IV, the molar ratio of the compound of formula V to the compound of formula VIa is 1-5; and / or, in the preparation method of the compound of formula IV, the base is an organic base, an inorganic base or a mixture thereof; and / or, in the preparation method of the compound of formula IV, the molar ratio of the base to the compound of formula VIa is 1-5; and / or, in the preparation method of the compound of formula IV, the solvent is an ether solvent, a chloroalkane solvent, a nitrile solvent or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula IV, the reaction temperature is 0-80 °C.

5. The preparation method according to claim 4, characterized in that, in the preparation method of the compound of formula IV, the molar ratio of the compound of formula V to the compound of formula VIa is 1-2; and / or, the organic base is potassium tert-butoxide, sodium methoxide, triethylamine, DMAP, pyridine, panpipidine or a mixture of any two or more thereof; the inorganic base is an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula IV, the molar ratio of the base to the compound of formula VIa is 1-2; and / or, the ether solvent is tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether or a mixture of any two or more thereof; the chloroalkane solvent is dichloromethane, dichloroethane, chloroform or a mixture of any two or more thereof; the nitrile solvent is acetonitrile; and / or, when R 4 is an ester protecting group, the reaction temperature is 40 - 60 °C; And / or, when R 4 is a silyl ether protecting group, the reaction temperature is 0 - 20 °C.

6. The preparation method according to claim 5, characterized in that, in the preparation method of the compound of formula IV, the organic base is sodium methoxide; the inorganic base is potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula IV, the molar ratio of the base to the compound of formula VIa is 1.5; and / or, in the preparation method of the compound of formula IV, the ether solvent is 1,4-dioxane; the chloroalkane solvent is dichloromethane.

7. The preparation method according to claim 1, characterized in that, the preparation method of the compound of formula IV further includes the preparation method of the compound of formula VIa and / or the preparation method of the compound of formula V; The preparation method of the compound of formula VIa includes the following steps: subjecting a compound of formula VIb and bromoacetic acid to a condensation reaction in the presence of a condensing agent and a base to obtain the compound of formula VIa; wherein, R 2 , R 3 and R 4 are defined as described in claim 1; The preparation method of the compound of formula V includes the following steps: reacting a compound of formula VII with paraformaldehyde in the presence of a base to obtain the compound of formula V; Among them, R 1 is defined as described in claim 1.

8. The preparation method according to claim 7, characterized in that, the preparation method of the compound of formula VIa includes the preparation method of the compound of formula VIb, and the preparation method of the compound of formula VIb includes the following steps: removing 4-methoxytriphenylmethyl connected to the amino group in the compound of formula VIc to obtain the compound of formula VIb; wherein, R 2 , R 3 and R 4 are as described in claim 1.

9. The preparation method according to claim 8, characterized in that, the preparation method of the compound of formula VIb includes the preparation method of the compound of formula VIc, and the preparation method of the compound of formula VIc includes the following steps: carrying out a hydroxyl protection reaction on the compound of formula VId and a hydroxyl protection reagent to obtain the compound of formula VIc; Among them, R 2 , R 3 and R 4 are as described in claim 1.

10. The preparation method according to claim 9, characterized in that, the preparation method of the compound of formula VIc includes the preparation method of the compound of formula VId, and the preparation method of the compound of formula VId includes the following steps: (i) Reacting irinotecan with trimethylchlorosilane; (ii) Reacting the reaction solution of step (i) with 4-methoxytriphenylmethyl chloride in the presence of a base to obtain the compound of formula VId; Among them, R 2 and R 3 are defined as described in claim 1.

11. The preparation method according to claim 7, characterized in that, the preparation method of the compound of formula V includes the preparation method of the compound of formula VII, and the preparation method of the compound of formula VII includes the following steps: reacting the compound of formula VIII with a sulfonyl azide compound in the presence of a base and a catalyst in a solvent to obtain the compound of formula VII; wherein, R 1 is defined as described in claim 1.

12. The preparation method according to claim 11, characterized in that, the preparation method of the compound of formula VII includes the preparation method of the compound of formula VIII, and the preparation method of the compound of formula VIII includes the following steps: carrying out a de-Fmoc reaction on the compound of formula IX in the presence of a base and an organic solvent to obtain the compound of formula VIII; Among them, R 1 is defined as described in claim 1.

13. The preparation method according to claim 12, characterized in that, the preparation method of the compound of formula VIII includes the preparation method of the compound of formula IX, and the preparation method of the compound of formula IX includes the following steps: carrying out a coupling reaction on the compound of formula X and N-Fmoc-L-valine N-butadienamine imidate in a solvent to obtain the compound of formula IX; wherein, R 1 is defined as described in claim 1.

14. The preparation method according to claim 13, characterized in that, the preparation method of the compound of formula IX includes the preparation method of the compound of formula X, and the preparation method of the compound of formula X includes the following steps: carrying out a de-Fmoc reaction on the compound of formula XI in the presence of a base and a solvent to obtain the compound of formula X; wherein, R 1 is defined as described in claim 1.

15. The preparation method according to claim 14, characterized in that, The preparation method of the compound of formula X includes the preparation method of the compound of formula XI, and the preparation method of the compound of formula XI includes the following steps: reacting a compound of formula XII with an amino compound R 1 NH 2 in the presence of a base and in a solvent to carry out a coupling reaction to obtain the compound of formula XI; wherein, R 1 is defined as described in claim 1.

16. The preparation method according to claim 15, characterized in that, the preparation method of the compound of formula XI includes the preparation method of the compound of formula XII, and the preparation method of the compound of formula XII includes the following steps: reacting the compound of formula XIII and the compound of formula XIV in the presence of a base and a solvent to obtain the compound of formula XII; 17. The preparation method according to claim 7, characterized in that, In the method for preparing the compound of formula VIa, the solvent for the condensation reaction is dichloromethane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or a mixture of any two or more thereof; and / or, in the method for preparing the compound of formula VIa, the molar ratio of the bromoacetic acid to the compound of formula VIb is 1-5; and / or, in the method for preparing the compound of formula VIa, the condensing agent is dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide or its salt, 2-(7-azabenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate, propylphosphonic anhydride, benzotriazol-N,N,N',N'-tetramethyluronium hexafluorophosphate, diphenylphosphoryl azide, 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine or its salt; and / or, in the method for preparing the compound of formula VIa, the molar ratio of the condensing agent to the compound of formula VIb is 1-5; and / or, in the method for preparing the compound of formula VIa, the base used in the condensation reaction is N,N-diisopropylethylamine, triethylamine, 1,8-diazabicycloundec-7-ene or a mixture of any two or more thereof; and / or, in the method for preparing the compound of formula VIa, the molar ratio of the base used in the condensation reaction to the compound of formula VIb is 1-5; and / or, in the method for preparing the compound of formula VIa, the temperature of the condensation reaction is 20-50 °C; and / or, in the method for preparing the compound of formula VIa, the condensation reaction is carried out under the protection of an inert gas; and / or, in the method for preparing the compound of formula V, the molar ratio of the paraformaldehyde converted to formaldehyde to the compound of formula VII is 1-3; and / or, in the method for preparing the compound of formula V, the base is an organic base, an inorganic base or a mixture thereof; and / or, in the method for preparing the compound of formula V, the solvent is a mixed system of an ether solvent and water; and / or, in the method for preparing the compound of formula V, the reaction temperature is 10-40 °C.

18. The preparation method according to claim 17, characterized in that in the method for preparing the compound of formula VIa, the solvent for the condensation reaction is dichloromethane, N,N-dimethylformamide or a mixture thereof; and / or, in the method for preparing the compound of formula VIa, the molar ratio of the bromoacetic acid to the compound of formula VIb is 1.5-3; and / or, in the method for preparing the compound of formula VIa, the condensing agent is dicyclohexylcarbodiimide, 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine or its salt; and / or, in the method for preparing the compound of formula VIa, the molar ratio of the condensing agent to the compound of formula VIb is 1.5-3.0; and / or, in the method for preparing the compound of formula VIa, the base used in the condensation reaction is triethylamine and / or N,N-diisopropylethylamine; And / or, in the method for preparing the compound of formula VIa, the molar ratio of the base used in the condensation reaction to the compound of formula VIb is 2 - 4; And / or, in the method for preparing the compound of formula VIa, the temperature of the condensation reaction is 20 - 30 °C; And / or, in the method for preparing the compound of formula VIa, the condensation reaction is carried out in a nitrogen or helium environment.

19. The preparation method according to claim 18, wherein, in the method for preparing the compound of formula VIa, the solvent for the condensation reaction is dichloromethane; And / or, in the method for preparing the compound of formula VIa, the molar ratio of the bromoacetic acid to the compound of formula VIb is 1.5 - 2; And / or, in the method for preparing the compound of formula VIa, the condensing agent is 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine or its salt; And / or, in the method for preparing the compound of formula VIa, the molar ratio of the condensing agent to the compound of formula VIb is 1.5 - 2.0; And / or, in the method for preparing the compound of formula VIa, the base used in the condensation reaction is N,N-diisopropylethylamine; And / or, in the method for preparing the compound of formula VIa, the molar ratio of the base used in the condensation reaction to the compound of formula VIb is 2.0 - 3.

0.

20. The preparation method according to claim 19, wherein, in the method for preparing the compound of formula VIa, the condensing agent is 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride; And / or, in the method for preparing the compound of formula VIa, the molar ratio of the base used in the condensation reaction to the compound of formula VIb is 2.0 - 2.

5.

21. The preparation method according to claim 8, wherein, in the method for preparing the compound of formula VIb, the solvent for the de-4-methoxytrityl reaction is chloroform, dichloromethane or their mixture; And / or, in the method for preparing the compound of formula VIb, the deprotecting reagent for de-4-methoxytrityl is triisopropylsilane, triethylsilane or their mixture; And / or, in the method for preparing the compound of formula VIb, the molar ratio of the deprotecting reagent for de-4-methoxytrityl to the compound of formula VIc is 1 - 5; And / or, in the method for preparing the compound of formula VIb, the temperature of the de-4-methoxytrityl reaction is -20 to 10 °C; And / or, in the method for preparing the compound of formula VIb, the de-4-methoxytrityl reaction is carried out under the protection of an inert gas.

22. The preparation method according to claim 21, wherein, in the method for preparing the compound of formula VIb, the solvent for the de-4-methoxytrityl reaction is dichloromethane; And / or, in the method for preparing the compound of formula VIb, the deprotecting reagent for de-4-methoxytrityl is triethylsilane; And / or, in the method for preparing the compound of formula VIb, the molar ratio of the deprotecting reagent for de-4-methoxytrityl to the compound of formula VIc is 1 - 3; And / or, in the method for preparing the compound of formula VIb, the temperature of the reaction for removing 4-methoxytriphenylmethyl is -10 to 5 °C; And / or, in the method for preparing the compound of formula VIb, the reaction for removing 4-methoxytriphenylmethyl is carried out in a nitrogen or helium environment.

23. The preparation method according to claim 22, wherein, in the method for preparing the compound of formula VIb, the molar ratio of the deprotecting reagent used for removing 4-methoxytriphenylmethyl to the compound of formula VIc is 1.3 - 2.5; And / or, in the method for preparing the compound of formula VIb, the temperature of the reaction for removing 4-methoxytriphenylmethyl is -5 to 5 °C.

24. The preparation method according to claim 9, wherein, in the method for preparing the compound of formula VIc, the hydroxy-protecting reagent used is acetic anhydride, propionic anhydride, acetyl chloride, propionyl chloride, tert-butyldimethylchlorosilane or tert-butyldiphenylchlorosilane; And / or, in the method for preparing the compound of formula VIc, the molar ratio of the hydroxy-protecting reagent used to the compound of formula VId is 1 - 2; And / or, in the method for preparing the compound of formula VIc, the hydroxy-protection reaction is carried out in the presence of a base; And / or, in the method for preparing the compound of formula VIc, the solvent for the hydroxy-protection reaction is dichloromethane, dichloroethane, N,N-dimethylformamide, N,N-dimethylacetamide or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VIc, the temperature of the hydroxy-protection reaction is 0 - 40 °C; And / or, in the method for preparing the compound of formula VIc, the hydroxy-protection reaction is carried out under the protection of an inert gas.

25. The preparation method according to claim 24, wherein, in the method for preparing the compound of formula VIc, the hydroxy-protecting reagent used is acetic anhydride, acetyl chloride or tert-butyldiphenylchlorosilane; And / or, in the method for preparing the compound of formula VIc, the molar ratio of the hydroxy-protecting reagent used to the compound of formula VId is 1 - 1.5; And / or, in the method for preparing the compound of formula VIc, the base is triethylamine, 4-dimethylaminopyridine, N,N-diisopropylethylamine, 1,8-diazabicyclo-bicyclo(5,4,0)-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-ene, N-methylmorpholine, tetramethylethylenediamine, pyridine or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VIc, the solvent for the hydroxy-protection reaction is dichloromethane, N,N-dimethylformamide or a mixture thereof; And / or, in the method for preparing the compound of formula VIc, the temperature of the hydroxy-protection reaction is 10 - 30 °C; And / or, in the method for preparing the compound of formula VIc, the hydroxy-protection reaction is carried out in a nitrogen or helium environment.

26. The preparation method according to claim 25, wherein, in the method for preparing the compound of formula VIc, the hydroxy-protecting reagent used is acetic anhydride or tert-butyldiphenylchlorosilane; And / or, in the method for preparing the compound of formula VIc, the molar ratio of the hydroxyl protecting reagent used to the compound of formula VId is 1.1 - 1.44; And / or, in the method for preparing the compound of formula VIc, the base is triethylamine, 4-dimethylaminopyridine, N,N-diisopropylethylamine or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VIc, the temperature of the hydroxyl protection reaction is 20 - 30 °C.

27. The preparation method according to claim 10, characterized in that in the method for preparing the compound of formula VId, the solvents used in the reactions of steps (i) and (ii) are dichloromethane, chloroform, dichloroethane or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VId, in the reaction of step (i), the molar ratio of trimethylchlorosilane used to irinotecan is 1 - 3; And / or, in the method for preparing the compound of formula VId, the reaction temperature of step (i) is 20 - 60 °C; And / or, in the method for preparing the compound of formula VId, the molar ratio of 4-methoxytriphenylmethyl chloride in step (ii) to irinotecan in step (i) is 1 - 3; And / or, in the method for preparing the compound of formula VId, the base in step (ii) is triethylamine, 4-dimethylaminopyridine, N,N-diisopropylethylamine, 1,8-diazabicyclo - bicyclo(5,4,0)-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-ene, N-methylmorpholine, tetramethylethylenediamine, pyridine or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VId, the molar ratio of the base in step (ii) to irinotecan in step (i) is 2 - 5; And / or, in the method for preparing the compound of formula VId, the reaction temperature of step (ii) is 0 - 40 °C.

28. The preparation method according to claim 27, characterized in that in the method for preparing the compound of formula VId, the solvents used in the reactions of steps (i) and (ii) are dichloromethane; And / or, in the method for preparing the compound of formula VId, in the reaction of step (i), the molar ratio of trimethylchlorosilane used to irinotecan is 1.2 - 2.0; And / or, in the method for preparing the compound of formula VId, the reaction temperature of step (i) is 40 - 45 °C; And / or, in the method for preparing the compound of formula VId, the molar ratio of 4-methoxytriphenylmethyl chloride in step (ii) to irinotecan in step (i) is 1.2 - 2.0; And / or, in the method for preparing the compound of formula VId, the base in step (ii) is triethylamine, 4-dimethylaminopyridine, N,N-diisopropylethylamine or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VId, the molar ratio of the base in step (ii) to irinotecan in step (i) is 3 - 4; And / or, in the method for preparing the compound of formula VId, the reaction temperature of step (ii) is 10 - 30 °C.

29. The preparation method according to claim 28, characterized in that in the preparation method of the compound of formula VId, in the reaction of step (i), the molar ratio of trimethylchlorosilane to irinotecan used is 1.2; and / or, in the preparation method of the compound of formula VId, the reaction temperature of step (i) is 45 °C; and / or, in the preparation method of the compound of formula VId, the molar ratio of 4-methoxytriphenylmethyl chloride in step (ii) to irinotecan in step (i) is 1.2; and / or, in the preparation method of the compound of formula VId, the base in step (ii) is N,N-diisopropylethylamine; and / or, in the preparation method of the compound of formula VId, the molar ratio of the base in step (ii) to irinotecan in step (i) is 3; and / or, in the preparation method of the compound of formula VId, the reaction temperature of step (ii) is 20 - 30 °C.

30. The preparation method according to claim 17, characterized in that in the preparation method of the compound of formula V, the molar ratio of paraformaldehyde in terms of formaldehyde to the compound of formula VII is 1 - 2; and / or, in the preparation method of the compound of formula V, the base is an inorganic base; and / or, in the preparation method of the compound of formula V, the ether solvent is tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula V, the reaction temperature is 25 - 40 °C.

31. The preparation method according to claim 17, characterized in that in the preparation method of the compound of formula V, the molar ratio of paraformaldehyde in terms of formaldehyde to the compound of formula VII is 1.5; and / or, in the preparation method of the compound of formula V, the organic bases are potassium tert-butoxide, sodium methoxide, triethylamine, DMAP, pyridine, pipidine or a mixture of any two or more thereof; the inorganic bases are alkali metal carbonates, alkali metal hydroxides, alkali metal phosphates or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula V, the ether solvent is 1,4-dioxane; and / or, in the preparation method of the compound of formula V, the reaction temperature is 25 - 30 °C.

32. The preparation method according to claim 31, characterized in that in the preparation method of the compound of formula V, the organic base is sodium methoxide; the inorganic bases are sodium bicarbonate, sodium carbonate, potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof.

33. The preparation method according to claim 32, characterized in that in the preparation method of the compound of formula V, the inorganic base is sodium bicarbonate.

34. The preparation method according to claim 33, characterized in that in the preparation method of the compound of formula V, the molar ratio of sodium bicarbonate to the compound of formula VII is 1 - 4.

35. The preparation method according to claim 34, characterized in that in the preparation method of the compound of formula V, the molar ratio of sodium bicarbonate to the compound of formula VII is 1 - 2.

36. The preparation method according to claim 35, characterized in that, in the preparation method of the compound of formula V, the molar ratio of sodium bicarbonate to the compound of formula VII is 1.

4.

37. The preparation method according to claim 11, characterized in that, in the preparation method of the compound of formula VII, the sulfonyl azide compound is 1H-imidazole-1-sulfonyl azide hydrochloride, 2-azido-1,3-dimethylimidazolium hexafluorophosphate, trifluoromethanesulfonyl azide, p-toluenesulfonyl azide or methanesulfonyl azide; and / or, in the preparation method of the compound of formula VII, the molar ratio of the sulfonyl azide compound to the compound of formula VIII is 1.0 - 1.5; and / or, in the preparation method of the compound of formula VII, the base is an organic base, an inorganic base or a mixture thereof; and / or, in the preparation method of the compound of formula VII, the molar ratio of the base to the compound of formula VIII is 1.5 - 3.0; and / or, in the preparation method of the compound of formula VII, the catalyst is a copper salt; and / or, in the preparation method of the compound of formula VII, the solvent is a mixed solvent of an organic solvent and water; and / or, in the preparation method of the compound of formula VII, the reaction temperature is 10 - 40 °C.

38. The preparation method according to claim 37, characterized in that, in the preparation method of the compound of formula VII, the sulfonyl azide compound is 1H-imidazole-1-sulfonyl azide hydrochloride; and / or, in the preparation method of the compound of formula VII, the molar ratio of the sulfonyl azide compound to the compound of formula VIII is 1.0 - 1.2; and / or, in the preparation method of the compound of formula VII, the inorganic base is an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof; the organic base is potassium tert-butoxide, triethylamine, DMAP, pyridine, panpidine, 2,6-dimethylpyridine or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula VII, the molar ratio of the base to the compound of formula VIII is 2.0 - 2.5; and / or, in the preparation method of the compound of formula VII, the catalyst is copper sulfate; and / or, in the preparation method of the compound of formula VII, the molar ratio of the copper salt to the compound of formula VIII is 0.1 - 0.5; and / or, in the preparation method of the compound of formula VII, the organic solvent is an alcohol solvent, a chloroalkane solvent, an ether solvent or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula VII, the reaction temperature is 25 - 40 °C.

39. The preparation method according to claim 38, characterized in that, in the preparation method of the compound of formula VII, the molar ratio of the sulfonyl azide compound to the compound of formula VIII is 1.02; and / or, in the preparation method of the compound of formula VII, the inorganic base is potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VII, the molar ratio of the base to the compound of formula VIII is 2.0; And / or, in the method for preparing the compound of formula VII, the catalyst is copper sulfate pentahydrate; And / or, in the method for preparing the compound of formula VII, the molar ratio of the copper salt to the compound of formula VIII is 0.1 - 0.3; And / or, in the method for preparing the compound of formula VII, the organic solvent is a mixture of an alcohol solvent and a chloroalkane solvent; And / or, in the method for preparing the compound of formula VII, the reaction temperature is 25 - 30 °C.

40. The preparation method according to claim 38, wherein, in the method for preparing the compound of formula VII, the molar ratio of the copper salt to the compound of formula VIII is 0.1 - 0.2; And / or, in the method for preparing the compound of formula VII, the alcohol solvent is methanol, ethanol, isopropanol or a mixture of any two or more thereof; the chloroalkane solvent is dichloromethane, chloroform, dichloroethane or a mixture of any two or more thereof; the ether solvent is tetrahydrofuran, diethyl ether, 1,4 - dioxane, anisole, methyl tert - butyl ether or a mixture of any two or more thereof.

41. The preparation method according to claim 40, wherein, in the method for preparing the compound of formula VII, the alcohol solvent is methanol; the chloroalkane solvent is dichloromethane.

42. The preparation method according to claim 12, wherein, in the method for preparing the compound of formula VIII, the base is an organic base, an inorganic base or a mixture thereof; And / or, in the method for preparing the compound of formula VIII, the volume ratio of the base to the organic solvent is 0.1 - 0.5; And / or, in the method for preparing the compound of formula VIII, the organic solvent is DMF, DMSO, tetrahydrofuran, 1,4 - dioxane or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VIII, the temperature of the de - Fmoc reaction is 10 - 40 °C.

43. The preparation method according to claim 42, wherein, in the method for preparing the compound of formula VIII, the base is an organic base; And / or, in the method for preparing the compound of formula VIII, the volume ratio of the base to the organic solvent is 0.2 - 0.3; And / or, in the method for preparing the compound of formula VIII, the organic solvent is DMF; And / or, in the method for preparing the compound of formula VIII, the temperature of the de - Fmoc reaction is 25 - 40 °C.

44. The preparation method according to claim 42, wherein, in the method for preparing the compound of formula VIII, the organic base is diethylamine, potassium tert - butoxide, triethylamine, DMAP, pyridine, panpipidine, 2,6 - dimethylpyridine or a mixture of any two or more thereof; the inorganic base is an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula VIII, the volume ratio of the base to the organic solvent is 0.2; And / or, in the method for preparing the compound of formula VIII, the temperature of the Fmoc deprotection reaction is 25 - 30 °C.

45. The preparation method according to claim 44, wherein, in the method for preparing the compound of formula VIII, the organic base is ethylenediamine; the inorganic base is potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof.

46. The preparation method according to claim 13, wherein, in the method for preparing the compound of formula IX, the molar ratio of the N-Fmoc-L-valine N-butadienamine imidate to the compound of formula X is 0.8 - 5; And / or, in the method for preparing the compound of formula IX, the solvent is DMF, DMSO, acetonitrile, dichloromethane, dichloroethane or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula IX, the temperature of the coupling reaction is 10 - 40 °C.

47. The preparation method according to claim 46, wherein, in the method for preparing the compound of formula IX, the molar ratio of the N-Fmoc-L-valine N-butadienamine imidate to the compound of formula X is 0.8 - 1.2; And / or, in the method for preparing the compound of formula IX, the solvent is dichloromethane; And / or, in the method for preparing the compound of formula IX, the temperature of the coupling reaction is 35 - 40 °C.

48. The preparation method according to claim 47, wherein, in the method for preparing the compound of formula IX, the molar ratio of the N-Fmoc-L-valine N-butadienamine imidate to the compound of formula X is 1.

49. The preparation method according to claim 14, wherein, in the method for preparing the compound of formula X, the base is an organic base, an inorganic base or a mixture thereof; And / or, in the method for preparing the compound of formula X, the solvent is DMF, DMSO, tetrahydrofuran, 1,4-dioxane or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula X, the volume ratio of the base to the solvent is 0.2 - 0.5; And / or, in the method for preparing the compound of formula X, the reaction temperature of the Fmoc deprotection reaction is 10 - 40 °C.

50. The preparation method according to claim 49, wherein, in the method for preparing the compound of formula X, the organic base is diethylamine, potassium tert-butoxide, triethylamine, DMAP, pyridine, panpipidine, 2,6-lutidine or a mixture of any two or more thereof; the inorganic base is an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula X, the solvent is DMF; And / or, in the method for preparing the compound of formula X, the volume ratio of the base to the solvent is 0.3 - 0.4; And / or, in the method for preparing the compound of formula X, the reaction temperature of the Fmoc deprotection reaction is 25 - 40 °C.

51. The preparation method according to claim 50, characterized in that, in the preparation method of the compound of formula X, the organic base is ethylenediamine; the inorganic base is potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula X, the volume ratio of the base to the solvent is 0.3; and / or, in the preparation method of the compound of formula X, the reaction temperature of the Fmoc deprotection reaction is 25 - 30 °C.

52. The preparation method according to claim 15, characterized in that, In the method for preparing the compound of formula XI, the molar ratio of the amino compound R 1 NH 2 to the compound of formula XII is 1.0 - 3.0; and / or, in the preparation method of the compound of formula XI, the base is an organic base, an inorganic base or a mixture thereof; and / or, in the preparation method of the compound of formula XI, the molar ratio of the base to the compound of formula XII is 2 - 4; and / or, in the preparation method of the compound of formula XI, the solvent is DMF, DMSO, dichloromethane, dichloroethane, tetrahydrofuran, 1,4 - dioxane or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula XI, the coupling reaction temperature is 10 - 40 °C.

53. The preparation method according to claim 52, characterized in that, In the method for preparing the compound of formula XI, the molar ratio of the amino compound R 1 NH 2 to the compound of formula XII is 1.1 - 1.5; and / or, in the preparation method of the compound of formula XI, the organic base is diethylamine, potassium tert - butoxide, triethylamine, DMAP, pyridine, pipidine, 2,6 - dimethylpyridine or a mixture of any two or more thereof; the inorganic base is an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula XI, the molar ratio of the base to the compound of formula XII is 2.5 - 3.0; and / or, in the preparation method of the compound of formula XI, the solvent is dichloromethane; and / or, in the preparation method of the compound of formula XI, the coupling reaction temperature is 25 - 40 °C.

54. The preparation method according to claim 53, characterized in that, in the preparation method of the compound of formula XI, the organic base is DMAP; the inorganic base is potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof; and / or, in the preparation method of the compound of formula XI, the molar ratio of the base to the compound of formula XII is 2.5; and / or, in the preparation method of the compound of formula XI, the coupling reaction temperature is 25 - 30 °C.

55. The preparation method according to claim 16, characterized in that, in the preparation method of the compound of formula XII, the molar ratio of the compound of formula XIV to the compound of formula XIII is 3.0 - 1.2; and / or, in the preparation method of the compound of formula XII, the base is an organic base, an inorganic base or a mixture thereof; and / or, in the preparation method of the compound of formula XII, the molar ratio of the base to the compound of formula XIII is 1.0 - 4.0; and / or, in the preparation method of the compound of formula XII, the solvent is DMF, DMSO, dichloromethane, dichloroethane, tetrahydrofuran, 1,4 - dioxane or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula XII, the reaction temperature is 10-40°C.

56. The preparation method according to claim 55, It is characterized in that In the preparation method of the compound of formula XII, the molar ratio of the compound of formula XIV to the compound of formula XIII is 2.0-1.5; And / or, in the preparation method of the compound of formula XII, the organic base is diethylamine, tert-butyl potassium, triethylamine, DMAP, pyridine, panpiperidin, 2,6-lutidine or a mixture of any two or more thereof; the inorganic base is an alkali metal hydroxide, an alkali metal carbonate, an alkali metal phosphate or a mixture thereof; And / or, in the method for preparing the compound of formula XII, the molar ratio of the base to the compound of formula XIII is 2.0-3.0; And / or, in the method for preparing the compound of formula XII, the solvent is dichloromethane; And / or, in the method for preparing the compound of formula XII, the reaction temperature is 25-40°C.

57. The preparation method according to claim 56, It is characterized in that In the preparation method of the compound of formula XII, the molar ratio of the compound of formula XIV to the compound of formula XIII is 1.5; And / or, in the preparation method of the compound of formula XII, the organic base is pyridine; the inorganic base is potassium phosphate, potassium carbonate, potassium hydroxide, cesium carbonate or a mixture of any two or more thereof; and / or, in the method for preparing the compound of formula XII, the molar ratio of the base to the compound of formula XIII is 2.0; And / or, in the method for preparing the compound of formula XII, the reaction temperature is 25-30°C.

58. A method for preparing a compound of formula III, comprising the following steps: Step 1: preparing a compound of formula IV according to the preparation method of the compound of formula IV as described in any one of claims 1 to 57; Step 2: performing a reduction reaction on the compound of formula IV and a reducing agent in an organic solvent and in the presence of an acid buffer to obtain a compound of formula III; in, R 1 、R 2 、R 3 and R 4 are defined as described in claim 1.

59. The preparation method according to claim 58, It is characterized in that In the preparation method of the compound of formula III, the reducing agent is triphenylphosphine, tri-tert-butylphosphine or trimethylphosphine; And / or, in the method for preparing the compound of formula III, the molar ratio of the reducing agent to the compound of formula IV is 1-5; And / or, in the method for preparing the compound of formula III, the organic solvent is an ether solvent; And / or, in the method for preparing the compound of formula III, the acid buffer is an acetate buffer or a formic acid buffer; And / or, in the method for preparing the compound of formula III, the temperature of the reduction reaction is 0-20°C.

60. The preparation method according to claim 59, It is characterized in that In the preparation method of the compound of formula III, the reducing agent is trimethylphosphine; And / or, in the method for preparing the compound of formula III, the molar ratio of the reducing agent to the compound of formula IV is 1-2; And / or, in the method for preparing the compound of formula III, the organic solvent is tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula III, the acid buffer solution is an acetate buffer solution; And / or, in the method for preparing the compound of formula III, the temperature of the reduction reaction is 0-10°C.

61. The preparation method according to claim 60, wherein, in the method for preparing the compound of formula III, the molar ratio of the reducing agent to the compound of formula IV is 1.0-1.5; And / or, in the method for preparing the compound of formula III, the organic solvent is tetrahydrofuran; And / or, in the method for preparing the compound of formula III, the pH of the acid buffer solution is 4.0-6.0; And / or, in the method for preparing the compound of formula III, the temperature of the reduction reaction is 0-5°C.

62. The preparation method according to claim 61, wherein, in the method for preparing the compound of formula III, the molar ratio of the reducing agent to the compound of formula IV is 1.1-1.3; And / or, in the method for preparing the compound of formula III, the pH of the acid buffer solution is 4.5-5.

5.

63. The preparation method according to claim 62, wherein, in the method for preparing the compound of formula III, the pH of the acid buffer solution is 5.

0.

64. A method for preparing a compound of formula II, the method for preparing the compound of formula II comprising the following steps: Step 1: Prepare the compound of formula III according to the method for preparing the compound of formula III as described in any one of claims 58-63; Step 2: Couple the compound of formula III and N-succinimidyl 6-(maleimidyl)hexanoate in a solvent to obtain the compound of formula II; wherein, R 1 、R 2 、R 3 and R 4 are defined as described in claim 1.

65. The preparation method according to claim 64, wherein, in the method for preparing the compound of formula II, the molar ratio of N-succinimidyl 6-(maleimidyl)hexanoate to the compound of formula III is 1-5; And / or, in the method for preparing the compound of formula II, the solvent is an amide solvent, a chloroalkane solvent, an ether solvent, a nitrile solvent or a mixture of any two or more thereof; And / or, in the method for preparing the compound of formula II, the reaction temperature is 0-50°C.

66. The preparation method according to claim 65, wherein, in the method for preparing the compound of formula II, the molar ratio of N-succinimidyl 6-(maleimidyl)hexanoate to the compound of formula III is 1-2; And / or, in the method for preparing the compound of formula II, the amide solvent is N,N-dimethylformamide, N,N-dimethylacetamide or a mixture thereof; the chloroalkane solvent is dichloromethane, chloroform, dichloroethane or a mixture of any two or more thereof; the ether solvent is tetrahydrofuran, diethyl ether, 1,4-dioxane, anisole, methyl tert-butyl ether or a mixture of any two or more thereof; the nitrile solvent is acetonitrile; And / or, in the method for preparing the compound of formula II, the reaction temperature is 25-40 °C.

67. The preparation method according to claim 66, characterized in that in the method for preparing the compound of formula II, the molar ratio of the 6-(maleimidyl)hexanoic acid N-hydroxysuccinimide ester to the compound of formula III is 1.0-1.5; And / or, in the method for preparing the compound of formula II, the amide solvent is N,N-dimethylformamide; the chloroalkane solvent is dichloromethane; the ether solvent is tetrahydrofuran.

68. A method for preparing a compound of formula I, which comprises the following steps: Step 1: Prepare the compound of formula II according to the method for preparing the compound of formula II as described in any one of claims 64-67; Step 2: Remove the R protecting group of the compound of Formula II to obtain the compound of Formula I; 4 ​ wherein, R 1 、R 2 、R 3 and R 4 are defined as described in claim 1.

69. The preparation method according to claim 68, characterized in that When the hydroxyl protecting group is an ester protecting group, R 4 is acetyl, propionyl, benzoyl or pivaloyl; And / or, when the hydroxyl protecting group is a silyl ether protecting group, R 4 is trimethylsilyl, triisopropylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl or tritert-butylsilyl; and / or, when the hydroxyl protecting group is an ester protecting group, removing R 4 The deprotecting reagent used for removing the protecting group is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, or acetyl chloride / methanol; And / or, when the hydroxyl protecting group is an ester protecting group, removing R 4 The molar ratio of the deprotecting reagent used to remove the protecting group to the compound of formula II is 0.5 - 2; And / or, when the hydroxyl protecting group is an ester protecting group, removing R 4 The solvent used for removing the protecting group is methanol, ethanol, isopropanol, dichloromethane or a mixture of any two or more of them; And / or, when the hydroxyl protecting group is an ester protecting group, the temperature for the reaction of removing the R 4 protecting group is 10 - 50 °C; And / or, when the hydroxyl protecting group is a silyl ether protecting group, removing R 4 The deprotecting reagent used for removing the protecting group is lithium hydroxide, tetrabutylammonium fluoride / acetic acid, sodium hydroxide, pyridine hydrogen fluoride complex, tert-butylammonium fluoride or tert-butylammonium fluoride / acetic acid; And / or, when the hydroxyl protecting group is a silyl ether protecting group, removing R 4 The molar ratio of the deprotecting reagent used to remove the protecting group to the compound of formula II is 1.2 - 3; And / or, when the hydroxyl protecting group is a silyl ether protecting group, the solvent used for removing the R 4 protecting group is methanol, ethanol, isopropanol, dichloromethane or a mixture of any two or more thereof; And / or, when the hydroxyl protecting group is a silyl ether protecting group, the temperature of the reaction for removing the R 4 protecting group is 10 - 50 °C.

70. The preparation method according to claim 69, characterized in that When the hydroxyl protecting group is an ester protecting group, R 4 is an acetyl group; and / or, when the hydroxyl protecting group is a silyl ether protecting group, R 4 is tert-butyldiphenylsilyl; And / or, when the hydroxyl protecting group is an ester protecting group, removing R 4 The deprotecting reagent used for removing the protecting group is acetyl chloride / methanol; And / or, when the hydroxyl protecting group is an ester protecting group, removing R 4 The molar ratio of the deprotecting reagent used for removing the protecting group to the compound of formula II is 0.5 - 1; And / or, when the hydroxyl protecting group is an ester protecting group, removing R 4 The solvent used for removing the protecting group is "a mixed solvent of methanol and dichloromethane" or "a mixed solvent of ethanol and dichloromethane"; And / or, when the hydroxyl protecting group is an ester protecting group, the temperature for the reaction of removing the R 4 protecting group is 20 - 30 °C; and / or, when the hydroxyl protecting group is a silyl ether protecting group, removing R 4 The deprotecting reagent used for removing the protecting group is tetrabutylammonium fluoride or tetrabutylammonium fluoride / acetic acid; and / or, when the hydroxyl protecting group is a silyl ether protecting group, removing R 4 The molar ratio of the deprotecting reagent used to remove the protecting group to the compound of formula II is 1.2 - 1.6; And / or, when the hydroxyl protecting group is a silyl ether protecting group, the solvent used for removing the R 4 protecting group is "a mixed solvent of methanol and dichloromethane" or "a mixed solvent of ethanol and dichloromethane"; And / or, when the hydroxyl protecting group is a silyl ether protecting group, the temperature of the reaction for removing the R 4 protecting group is 20 - 30 °C.

71. The preparation method according to claim 70, characterized in that When the hydroxyl protecting group is a silyl ether protecting group, removing R 4 The molar ratio of the deprotecting reagent used to remove the protecting group to the compound of formula II is 1.

5.

72. A compound having a structure as shown in formula VIa or V; wherein, R 1 、R 2 、R 3 and R 4 are defined as described in claim 1.

73. The compound according to claim 72, characterized in that R 1 is 2-(methylsulfonyl)ethyl; R 2 is methyl; R 3 is fluorine; R 4 is acetyl or tert-butyldiphenylsilyl.

74. A method for preparing a compound according to claim 72 or 73, characterized in that the method for preparing the compound of formula VIa comprises the following steps: subjecting the compound of formula VIb and bromoacetic acid to a condensation reaction in the presence of a condensing agent and a base to obtain the compound of formula VIa; the reaction conditions are as described in any one of claims 7 or 17-20; wherein, R 2 , R 3 and R 4 are defined as described in claim 1; the method for preparing the compound of formula V comprises the following steps: reacting the compound of formula VII with paraformaldehyde in the presence of a base to obtain the compound of formula V; the reaction conditions are as described in any one of claims 7, 17 or 30-36; Among them, R 1 is defined as described in claim 1.

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