Method for producing auristatin derivative intermediates

Abstract

The present invention provides a process route for producing auristatin derivative intermediates, which effectively avoids the use of norephedrine in the synthesis route compared to the prior art. Furthermore, the process route for auristatin derivative intermediates according to the present invention allows for the production of the target product in a single step, effectively avoids the generation of reaction intermediates, has a simple purification method, and produces a high yield and purity of the final product, making it suitable for industrial-scale scaling up.

Description

[Technical Field]

[0001] The present invention relates to the technology of synthesis of pharmaceutical intermediates, and more particularly to a method for producing auristatin derivative intermediates. [Background technology]

[0002] An antibody-drug conjugate (ADC) is a type of antitumor drug containing three components: an antibody, a linker, and a drug, with the antibody and drug components linked via a linker. Its mechanism of action involves using the target-directivity of the antibody to deliver the drug to target cells (such as tumor cells) and then releasing the drug to kill the tumor cells. Currently, many naturally occurring and chemically synthesized cell drugs are known, but only a few drug structures are applicable to ADCs. This is mainly because drugs used as payloads for ADCs must possess multiple characteristics, such as extremely high cytotoxic activity, intracellular targeting, and a small molecular size. Among these, auristatin compounds (such as MMAE and MMAF) are cytotoxic molecules that have been successfully developed for various ADC applications.

[0003] MMAE (Monomethyl Auristantin E) is a chemically synthesized auristatin derivative that effectively inhibits mitosis by suppressing tubulin polymerization. MMAE is currently sold at a very high price. One reason for this is thought to be that the known synthetic routes for MMAE involve multiple steps, are relatively complex, often require harsh conditions such as extremely low temperatures, and result in low yields. Furthermore, in some cases, regulated compounds such as norephedrine are used as substrates.

[0004] Currently, the most common manufacturing route for MMAE is as follows: Here, compound (I-1) is a common starting material (auristatin derivative intermediate).

[0005] [ka]

[0006] Regarding the production of the starting material compound (I-1), Chinese Patent Publication No. CN107921144A discloses a production method in which compound B is first prepared from compound A (see Example 6 on page 49 of the specification), and then reacted with various intermediates to produce auristatin derivatives with different substituents (see Example 11 on page 51, Example 17 on page 53, Example 25 on page 55, etc. of the specification).

[0007] [ka]

[0008] Furthermore, Chinese Patent Publication No. CN104185477A discloses a method for producing compound (I-1) based on compound B (see line 1061 on page 130 of the specification), and the production route is as follows:

[0009] [ka] [Overview of the project] [Problems that the invention aims to solve]

[0010] The manufacturing process for compound (I-1) described above is a two-step reaction (i.e., compound A → compound B → compound (I-1)), which has technical flaws such as a decrease in the yield of the final product and an increase in production costs. Furthermore, norephedrine, which is used as a raw material for synthesis, is a compound that can be a precursor to stimulants and can be converted into methamphetamine, also known as "meth," through a simple chemical transformation. Since norephedrine is a regulated substance and its sources are limited, there is a serious flaw that increases the complexity and risks of the manufacturing process. [Means for solving the problem]

[0011] In view of the problems of the prior art, the present invention provides a novel process route for producing the above auristatin derivative intermediate. Specifically, the auristatin derivative intermediate according to the present invention is a compound represented by the following formula (I), or an enantiomer, racemate, or pharmaceutically acceptable salt thereof.

[0012]

Chemical formula

[0013] Its production route is as follows.

[0014]

Chemical formula

[0015] In the formula, R1, R2, and R3 are independently selected from the group consisting of H, a C1-C8 alkyl group, a C1-C8 heteroalkyl group, a C2-C8 alkenyl group, a C2-C8 alkynyl group, a C3-C8 heterocyclic ring, a C3-C8 carbocyclic ring, an aryl group, a C1-C8 aralkyl group, a C1-C8 alkylcarbocyclic ring, and a C1-C8 alkylheterocyclic ring, R4 is an amino protecting group, R5 is O or S, R6 is selected from the group consisting of H, -OH, a C1-C8 alkyl group, a C3-C8 carbocyclic ring, and -O-(C1-C8 alkyl group).

[0016] The method for producing the auristatin derivative intermediate according to the present invention comprises Step 1 of dissolving compound a in an appropriate amount of organic solvent 1, Step 2 of adding an aqueous solution of an inorganic base to the solution formed in Step 1 and reacting, Step 3 of post-treating the reaction system formed in Step 2 to obtain the compound represented by the above formula (I). Here, the organic solvent 1 is any one or more selected from the group consisting of N,N-dimethylformamide, N-methylpyrrolidone, methanol, ethanol, isopropanol, acetonitrile, acetone, tetrahydrofuran, and 1,4-dioxane.

[0017] In some preferred embodiments, the organic solvent 1 is methanol. In some other preferred embodiments, the organic solvent 1 is anhydrous ethanol. In some other preferred embodiments, the organic solvent 1 is tetrahydrofuran. In some other preferred embodiments, the organic solvent 1 is acetonitrile.

[0018] In some other preferred embodiments, the organic solvent 1 is a mixed solution of any two selected from the group consisting of N,N-dimethylformamide, N-methylpyrrolidone, methanol, ethanol, isopropanol, acetonitrile, acetone, tetrahydrofuran, and 1,4-dioxane. For example, a solution obtained by mixing methanol and ethanol in any volume ratio, a solution obtained by mixing N,N-dimethylformamide and N-methylpyrrolidone in any volume ratio, a solution obtained by mixing N-methylpyrrolidone and methanol in any volume ratio, a solution obtained by mixing ethanol and isopropanol in any volume ratio, a solution obtained by mixing isopropyl alcohol and acetonitrile in any volume ratio, a solution obtained by mixing acetonitrile and acetone in any volume ratio, a solution obtained by mixing acetone and tetrahydrofuran in any volume ratio, a solution obtained by mixing tetrahydrofuran and 1,4-dioxane in any volume ratio, or a solution obtained by mixing other solvents in any volume ratio. Also, when the organic solvent 1 is a mixed solution of two solvents, the volume ratio of the two solvents may be, for example, 1:1, 1:2, 1:3, 1:4…, 2:1, 3:1, 4:1…, or other volume ratios.

[0019] Preferably, R1 is selected from the group consisting of H, C1-C8 alkyl group, C1-C8 heteroalkyl group, C2-C8 alkenyl group, C2-C8 alkynyl group, C3-C8 heterocycle, C3-C8 carbon ring, aryl group, C1-C8 alkaryl group, C1-C8 alkyl carbon ring, and C1-C8 alkyl heterocycle. Preferably, R1 is a C1-C8 alkyl group. More preferably, R1 is selected from the group consisting of methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, and octyl group. Even more preferably, R1 is a methyl group or an ethyl group.

[0020] Preferably, R2 is selected from the group consisting of H, C1-C8 alkyl group, C1-C8 heteroalkyl group, C2-C8 alkenyl group, C2-C8 alkynyl group, C3-C8 heterocycle, C3-C8 carbon ring, aryl group, C1-C8 alkaryl group, C1-C8 alkyl carbon ring, and C1-C8 alkyl heterocycle. Preferably, R2 is an aryl group.

[0021] Preferably, R3 is selected from the group consisting of H, C1-C8 alkyl group, C1-C8 heteroalkyl group, C2-C8 alkenyl group, C2-C8 alkynyl group, C3-C8 heterocycle, C3-C8 carbon ring, aryl group, C1-C8 alkaryl group, C1-C8 alkyl carbon ring, and C1-C8 alkyl heterocycle. Preferably, R3 is a C1-C8 alkyl group. More preferably, R3 is selected from the group consisting of methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, and octyl group. Even more preferably, R3 is a methyl group or an ethyl group.

[0022] The aforementioned R4 is selected from the group consisting of a Boc protecting group, a Cbz protecting group, an Fmoc protecting group, and a benzyl group. In some specific embodiments, R4 is a Boc protecting group. In some specific embodiments, R4 is a Cbz protecting group. In some specific embodiments, R4 is an Fmoc protecting group. In some other specific embodiments, R4 is a benzyl group.

[0023] Preferably, R5 is O. Alternatively, R5 is S.

[0024] Preferably, R6 is selected from the group consisting of H, OH, C1-C8 alkyl groups, C3-C8 carbon rings, and O-(C1-C8 alkyl groups). More preferably, R6 is O-(C1-C8 alkyl group). Even more preferably, R6 is a methoxy group.

[0025] Preferably, compound a has a structure selected from the following:

[0026] [ka]

[0027] Preferably, the compound represented by formula (I) has the following structure:

[0028] [ka]

[0029] The inorganic base in step 2 is selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, potassium carbonate, cesium carbonate, and sodium carbonate. In some preferred embodiments, the inorganic base in step 2 is lithium hydroxide. In some other preferred embodiments, the inorganic base in step 2 is sodium hydroxide. In some other preferred embodiments, the inorganic base in step 2 is potassium hydroxide. In some other preferred embodiments, the inorganic base in step 2 is calcium hydroxide. In some other preferred embodiments, the inorganic base in step 2 is potassium carbonate. In some other preferred embodiments, the inorganic base in step 2 is cesium carbonate. In some other preferred embodiments, the inorganic base in step 2 is sodium carbonate.

[0030] In some specific embodiments, the mass fraction of the inorganic base aqueous solution is 2% to 15%. Preferably, the mass fraction of the inorganic base aqueous solution is 3% to 10%. In some preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 2%. In some preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 3%. In some preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 4%. In some preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 5%. In some other preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 6%. In some other preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 7%. In some other preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 8%. In some other preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 9%. In some other preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 10%. In some other preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 11%. In some other preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 12%. In some other preferred embodiments, the mass fraction of the inorganic alkali aqueous solution is 13%. In some other preferred embodiments, the mass fraction of the inorganic alkaline aqueous solution is 14%. In some other preferred embodiments, the mass fraction of the inorganic alkaline aqueous solution is 15%. In some other preferred embodiments, the mass fraction of the inorganic base aqueous solution may be, for example, 4.8%, 5.5%, 5.7%, 7.4%, 9.4%, 8.9%, 9.1%, etc.

[0031] In some other specific embodiments, the weight-to-volume ratio (g / ml) of compound a to organic solvent 1 is W 化合物a :W 有機溶媒1 =1:3~30. Preferably, the weight-to-volume ratio of compound a to organic solvent 1 is 1:3~14. In some preferred embodiments, the weight-to-volume ratio (g / ml) of compound a to organic solvent 1 is W 化合物a :W 有機溶媒1= 1:3. In some other preferred embodiments, the weight-to-volume ratio (g / ml) of compound a to organic solvent 1 is W 化合物a :W 有機溶媒1 = 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, 1:26, 1:27, 1:28, 1:29, 1:30, or other non-integer ratios, such as approximately 1:3.1, ..., 1:3.2, ..., 1:5.27, 1:6.23, ..., 1:6.72, ..., 1:10.32, ..., 1:11.21, ..., 1:13.45, ... etc.

[0032] In some other specific embodiments, the molar ratio of compound a to inorganic base is 1:1 to 10. Preferably, the molar ratio of compound a to inorganic base is 1:1 to 5. In some preferred embodiments, the molar ratio of compound a to inorganic base is 1:1. In some preferred embodiments, the molar ratio of compound a to inorganic base is 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10. It will also be understood that in some other preferred embodiments, the molar ratio of compound a to inorganic base may be a non-integer ratio such as 1:1.1, ..., 1:1.5, ..., 1:2.6, ..., 1:4.8, ...

[0033] In some other specific embodiments, the reaction in step 2 is carried out at -10 to 78°C. Preferably, the reaction in step 2 is carried out at 5 to 40°C. More preferably, the reaction in step 2 is carried out at 15 to 35°C (e.g., 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C). In some preferred embodiments, the reaction in step 2 may be in the range of, for example, 20±5°C, ..., 30±5°C, ..., etc. Furthermore, the post-treatment in step 3 is carried out after adjusting the reaction system formed in step 2 to an acidic state.

[0034] More preferably, the post-treatment in step 3 is performed after adjusting the reaction system formed in step 2 to pH=1 to 6, for example, to pH=1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0. Of course, you can also use other pH values ​​such as 1.15, 2.26, or 3.48.

[0035] Furthermore, the post-treatment in step 3 mainly includes an extraction process and a crystallization process.

[0036] Furthermore, the extraction solvent used in the extraction process is one or more selected from the group consisting of ethyl acetate, dichloromethane, methyl tert-butyl ether, isopropyl acetate, and 2-methyltetrahydrofuran.

[0037] It should be understood that the volume of the extraction solvent does not limit the present invention. In some preferred embodiments, the weight-to-volume ratio (g / mL) of compound a to the extraction solvent is W 化合物a :V 抽出溶媒 = 1:10~30 (for example, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, 1:26, 1:27, 1:28, 1:29, 1:30, or other ratios such as approximately 1:14.55, 1:14.57, 1:19.49, 1:20.17, 1:24.66, etc., but not limited to these).

[0038] Furthermore, the crystallization solvent used in the crystallization process is one or more selected from the group consisting of N,N-dimethylformamide, N-methylpyrrolidone, methanol, ethanol, isopropyl alcohol, acetonitrile, acetone, 1,4-dioxane, ethyl acetate, dichloromethane, isopropyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, methyl tert-butyl ether, n-hexane, n-heptane, cyclohexane, and methylcyclopentane.

[0039] In some preferred embodiments, the crystallization solvent is one selected from the group consisting of N,N-dimethylformamide, N-methylpyrrolidone, methanol, ethanol, isopropyl alcohol, acetonitrile, acetone, 1,4-dioxane, ethyl acetate, dichloromethane, isopropyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, methyl tert-butyl ether, n-hexane, n-heptane, cyclohexane, and methylcyclopentane.

[0040] In some other preferred embodiments, the crystallization solvent is two selected from the group consisting of N,N-dimethylformamide, N-methylpyrrolidone, methanol, ethanol, isopropanol, acetonitrile, acetone, 1,4-dioxane, ethyl acetate, dichloromethane, isopropyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, methyl tert-butyl ether, n-hexane, n-heptane, cyclohexane, and methylcyclopentane (i.e., crystallization solvent 1 and crystallization solvent 2), for example, ethyl acetate and n-hexane, methyl tert-butyl ether and n-heptane, ethyl acetate and n-heptane, etc. Here, the volume ratio of crystallization solvent 1 and crystallization solvent 2 is arbitrary, but preferably 1:1, 1:2, 2:1, 1:3, 3:1, 1:4, 4:1, 1:5, 5:1, etc.

[0041] It should be understood that the volume of the crystallization solvent does not limit the present invention. In some preferred embodiments, the weight-to-volume ratio (g / mL) of compound a to the total volume of the crystallization solvent is W化合物a :V 晶析溶媒 = 1:3 to 10 (for example, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or other ratios, such as about 1:3.11, 1:3.36, 1:5.27, 1:5.6, 1:8.97, 1:9.17, etc., but not limited thereto)

[0042] Furthermore, the target temperature of the crystallization process (i.e., the lowest temperature during the crystallization process) is -25 to 60 °C. Preferably, the target temperature of the crystallization process is -10 to 40 °C. More preferably, the target temperature of the crystallization process is 0 to 10 °C, and it may be a specific temperature or range (for example, 0 °C, 2 °C, 3 °C, 4 °C, 5 °C, 6 °C, 7 °C, 8 °C, 9 °C, 10 °C, 2 ± 2 °C, 3 ± 2 °C, 4 ± 2 °C, 5 ± 2 °C, 6 ± 2 °C, 7 ± 2 °C, 8 ± 2 °C, etc.).

[0043] It should be understood that in the crystallization process, it may be carried out by first adding a crystallization solvent and then lowering the temperature of the whole system to the target temperature, or by first lowering the temperature of the whole system to the target temperature and then adding a crystallization solvent.

[0044] Furthermore, in addition to including an extraction process and a crystallization process, the post-treatment in Step 3 may further include other processes such as common operations like drying the extract, filtering and rotary distilling the extract, and filtering the crystallization system.

[0045] In the process route of the auristatin derivative intermediate according to the present invention, compared with the prior art, the use of nor-ephedrine, which is a regulated compound, is effectively avoided, and the reaction conditions are mild. Furthermore, according to the process route of the auristatin derivative intermediate of the present invention, the target product can be produced in one step, the generation of reaction intermediates can be effectively avoided, the purification method is simple, the yield and purity of the final product are high, and it is suitable for industrial scale-up.

Embodiments for Carrying out the Invention

[0046] (Definition) As used herein, the term "alkyl group" refers to a saturated aliphatic hydrocarbon group that is a linear or branched group containing 1 to 20 carbon atoms, preferably an alkyl group containing 1 to 12 carbon atoms, more preferably an alkyl group containing 1 to 10 carbon atoms, and most preferably an alkyl group containing 1 to 8 carbon atoms. Examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, sec-butyl group, n-pentyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, 2-methylbutyl group, 3-methylbutyl group, n-hexyl group, 1-ethyl-2-methylpropyl group, 1,1,2-trimethylpropyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 2,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2-ethylbutyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 2,3-dimethylbutyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 2,3-dimethylbutyl group Examples include, but are not limited to, diethylpentyl group, 2,4-dimethylpentyl group, 2,2-dimethylpentyl group, 3,3-dimethylpentyl group, 2-ethylpentyl group, 3-ethylpentyl group, n-octyl group, 2,3-dimethylhexyl group, 2,4-dimethylhexyl group, 2,5-dimethylhexyl group, 2,2-dimethylhexyl group, 3,3-dimethylhexyl group, 4,4-dimethylhexyl group, 2-ethylhexyl group, 3-ethylhexyl group, 4-ethylhexyl group, 2-methyl-2-ethylpentyl group, 2-methyl-3-ethylpentyl group, n-nonyl group, 2-methyl-2-ethylhexyl group, 2-methyl-3-ethylhexyl group, 2,2-diethylpentyl group, n-decyl group, 3,3-diethylhexyl group, 2,2-diethylhexyl group, and various branched isomers thereof. Alkyl groups may be substituted or unsubstituted. If substituted, substituents may be substituted on any linkage point.Preferably, the substituent is independently one or more selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, alkylamino groups, halogens, mercapto groups, hydroxyl groups, nitro groups, cyano groups, cycloalkyl groups, heterocycloalkyl groups, aryl groups, heteroaryl groups, cycloalkoxy groups, heterocycloalkoxy groups, cycloalkylthio groups, heterocycloalkylthio groups, and oxo groups.

[0047] As used herein, the term "heteroalkyl group" refers to an alkyl group containing one or more heteroatoms selected from the group consisting of N, O, and S, where the alkyl group is as defined above.

[0048] As used herein, the term "alkenyl group" refers to a linear or branched aliphatic hydrocarbon containing one carbon-carbon double bond and 2 to 8 carbon atoms. Examples of alkenyl groups include, but are not limited to, vinyl, allyl, n-butenyl, isobutenyl, 3-methylbuta-2-enyl, n-pentenyl, hexenyl, heptenyl, and octenyl groups.

[0049] As used herein, the term "alkynyl group" refers to a linear or branched aliphatic hydrocarbon containing a carbon-carbon triple bond and 2 to 8 carbon atoms. Examples of alkynyl groups include, but are not limited to, ethynyl, propynyl, n-butynyl, 2-butynyl, 3-methylbutynyl, n-pentynyl, hexynyl, heptynyl, and octinyl groups.

[0050] As used herein, "heterocyclic" is also called "heterocyclic group" and refers to saturated or partially unsaturated monocyclic or polycyclic hydrocarbon substituents containing 3 to 20 ring atoms, wherein one or more of the ring atoms are nitrogen, oxygen, and S(O). uThe heteroatom is selected from the group consisting of (where u is an integer from 0 to 2), and preferably contains 3 to 8 ring atoms. Examples of monocyclic heterocyclic groups include, but are not limited to, pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, thiomorpholinyl, and homopiperazinyl groups. Polycyclic heterocyclic groups include spirocyclic, fused, and bridging heterocyclic groups. The heterocyclic group may be optionally substituted or unsubstituted. If substituted, the substituent is preferably one or more selected independently from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, alkylamino groups, halogens, mercapto groups, hydroxyl groups, nitro groups, cyano groups, cycloalkyl groups, heterocycloalkyl groups, aryl groups, heteroaryl groups, cycloalkoxy groups, heterocycloalkoxy groups, cycloalkylthio groups, heterocycloalkylthio groups, and oxo groups.

[0051] As used herein, "aryl group" refers to a monocyclic or polycyclic (i.e., a ring sharing adjacent carbon atom pairs) group of 6 to 14 members, preferably 6 to 10 members, having a conjugated π-electron system, such as a phenyl group and a naphthyl group, preferably a phenyl group. The aryl ring may also be fused with a heteroaryl group, a heterocyclyl group, or a cycloalkyl group, provided that the ring bonded to the parent structure is an aryl ring. Examples include, but are not limited to, the following:

[0052] [ka]

[0053] The aryl group may be substituted or unsubstituted. If substituted, the substituent is preferably one or more groups independently selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, alkylamino groups, halogens, hydroxyl groups, nitro groups, cyano groups, cycloalkyl groups, heterocycloalkyl groups, aryl groups, heteroaryl groups, cycloalkoxy groups, heterocycloalkoxy groups, cycloalkylthio groups, and heterocycloalkylthio groups.

[0054] As used herein, the term "amino protecting group" refers to a group that protects an amino group using an easily removable group in order to maintain the amino group's integrity during reactions with other parts of the molecule. Examples include, but are not limited to, 9-fluorenylmethyloxycarbonyl (i.e., Fmoc protecting group), tert-butoxycarbonyl group (i.e., Boc protecting group), benzyloxycarbonyl group (i.e., Cbz protecting group), acetyl group, benzyl group, allyl group, and p-methoxybenzyl group. These groups may be optionally substituted with one to three substituents selected from halogens, alkoxy groups, and nitro groups.

[0055] As used herein, the term “antibody-drug conjugate” refers to a compound formed by the chemical reaction of an antibody / functional antibody fragment, a linker, and a toxin moiety, and generally has a structure consisting of three parts: an antibody or antibody-like ligand, a toxin moiety, and a linker that conjugates the antibody or antibody-like ligand to a drug. As used herein, the terms “drug” and “toxin moiety” generally refer to any compound having the desired biological activity and a reactive functional group useful for preparing the conjugates described herein. [Examples]

[0056] (Example 1)

[0057] [ka]

[0058] Compound (a-1) (4.46 g, 10 mmol) was dissolved in 14 ml of ethanol, and under a nitrogen atmosphere, a solution of lithium hydroxide (1.2 g, 50 mmol) in water (24 mL; here, this refers to the volume of water, and the same applies hereafter) was added dropwise. After the dropwise addition was complete, the mixture was stirred at room temperature (20-25°C) for 30 minutes, then adjusted to acidic (pH=5), and 65 mL of ethyl acetate was added for extraction. The ethyl acetate extract was collected, dried with anhydrous Na₂SO₄, and concentrated to a certain volume under reduced pressure. Next, a total of 25 ml of ethyl acetate and n-hexane (volume ratio 1:5) was added and stirred, and the solid gradually precipitated. The mixture was cooled to 0°C while stirring, filtered, and 3.15 g of a white solid, compound (I-1), was obtained (yield 75%, purity 99.5%). (Example 2)

[0059] [ka]

[0060] Compound (a-1) (4.46 g, 10 mmol) was dissolved in 14 ml of methanol, and a solution of lithium hydroxide (0.48 g, 20 mmol) in water (6 mL) was added dropwise under a nitrogen atmosphere. After the addition was complete, the mixture was stirred at 15°C for 30 minutes, then adjusted to acidic (pH=4), and 90 mL of ethyl acetate was added for extraction. The ethyl acetate extract was collected, dried with anhydrous Na₂SO₄, and concentrated to a certain volume under reduced pressure. Next, a total of 25 ml of ethyl acetate and n-hexane (volume ratio 1:5) was added and stirred, and the solid gradually precipitated. The mixture was cooled to 0°C while stirring, filtered, and 3.32 g of a white solid, compound (I-1), was obtained (yield 79%, purity 99.4%). (Example 3)

[0061] [ka]

[0062] Compound (a-1) (4.46 g, 10 mmol) was dissolved in 60 ml of ethanol, and a solution of sodium hydroxide (1.04 g, 26 mmol) in water (10 mL) was added dropwise under a nitrogen atmosphere. After the addition was complete, the mixture was stirred at 35°C for 30 minutes, then adjusted to acidic (pH=3), and extracted with 65 mL of dichloromethane. The dichloromethane extract was collected, dried with anhydrous Na₂SO₄, and concentrated to a certain volume under reduced pressure. Next, 40 ml of methyl tert-butyl ether was added and stirred, and a solid gradually precipitated. The mixture was cooled to 10°C while stirring, filtered, and 3.15 g of a white solid, compound (I-1), was obtained (yield 75%, purity 99.5%). (Example 4)

[0063] [ka]

[0064] Compound (a-1) (4.46 g, 10 mmol) was dissolved in 50 ml of methanol, and a solution of sodium hydroxide (0.44 g, 11 mmol) in water (4.5 mL) was added dropwise under a nitrogen atmosphere. After the dropwise addition was complete, the mixture was stirred at 35°C for 30 minutes, then adjusted to acidic (pH=2), and 90 mL of dichloromethane was added for extraction. The dichloromethane extract was collected, dried with anhydrous Na₂SO₄, and concentrated to a certain volume under reduced pressure. Next, a total of 15 ml of methyl tert-butyl ether and n-heptane (volume ratio 2:1) was added and stirred, and a solid gradually precipitated. The mixture was cooled to 0°C while stirring, filtered, and 3.57 g of a white solid, compound (I-1), was obtained (yield 85%, purity 99.1%). (Example 5)

[0065] [ka]

[0066] Compound (a-1) (4.46 g, 10 mmol) was dissolved in 30 ml of ethanol, and a solution of lithium hydroxide (1.20 g, 50 mmol) in water (12 mL) was added dropwise under a nitrogen atmosphere. After the addition was complete, the mixture was stirred at room temperature (20-25°C) for 30 minutes, then adjusted to acidic (pH=1), and extracted with 110 mL of ethyl acetate. The ethyl acetate extract was collected, dried with anhydrous Na₂SO₄, and concentrated to a certain volume under reduced pressure. Next, a total of 15 ml of ethyl acetate and n-heptane (volume ratio 1:2) was added and stirred, and the solid gradually precipitated. The mixture was cooled to 10°C while stirring, filtered, and 3.07 g of a white solid, compound (I-1), was obtained (yield 73%, purity 99.3%). (Example 6)

[0067] [ka]

[0068] Compound (a-2) (4.81 g, 10 mmol) was dissolved in 30 ml of methanol, and a solution of lithium hydroxide (1.20 g, 50 mmol) in water (20 mL) was added dropwise under a nitrogen atmosphere. After the addition was complete, the mixture was stirred at room temperature (20-25°C) for 30 minutes, then adjusted to acidic (pH=6), and extracted with 70 mL of ethyl acetate. The ethyl acetate extract was collected, dried with anhydrous Na₂SO₄, and concentrated to a certain volume under reduced pressure. Next, a total of 15 ml of ethyl acetate and n-heptane (volume ratio 1:2) was added and stirred, and the solid gradually precipitated. The mixture was cooled to 0°C while stirring, filtered, and 3.80 g of a white solid, compound (I-2), was obtained (yield 84%, purity 99.5%). (Example 7)

[0069] [ka]

[0070] Compound (a-3) (5.69 g, 10 mmol) was dissolved in 30 ml of ethanol, and a solution of lithium hydroxide (0.26 g, 11 mmol) in water (4.5 mL) was added dropwise under a nitrogen atmosphere. After the addition was complete, the mixture was stirred at room temperature (20-25°C) for 30 minutes, then adjusted to acidity (pH=5.5), and extracted with 140 mL of dichloromethane. The dichloromethane extract was collected, dried with anhydrous Na₂SO₄, and concentrated to a certain volume under reduced pressure. Next, 30 ml of methyl tert-butyl ether was added and stirred, and a solid gradually precipitated. The mixture was cooled to 10°C while stirring, filtered, and 1.95 g of a white solid, compound (I-3), was obtained (yield 36%, purity 99.2%). (Example 8)

[0071] [ka]

[0072] Compound (a-4) (4.36 g, 10 mmol) was dissolved in 45 ml of ethanol, and a solution of sodium hydroxide (0.44 g, 11 mmol) in water (4.5 mL) was added dropwise under a nitrogen atmosphere. After the addition was complete, the mixture was stirred at room temperature (20-25°C) for 30 minutes, then adjusted to acidity (pH=4.5), and extracted with 85 mL of ethyl acetate. The ethyl acetate extract was collected, dried with anhydrous Na₂SO₄, and concentrated to a certain volume under reduced pressure. Next, a total of 40 ml of ethyl acetate and n-heptane (volume ratio 1:2) was added and stirred, and the solid gradually precipitated. The mixture was cooled to 0°C while stirring, filtered, and 3.20 g of a white solid, compound (I-4), was obtained (yield 78%, purity 99.6%).

[0073] The above description represents only preferred embodiments and is presented as an example only, and is not intended to limit the combination of features necessary to carry out the invention. The subject matter provided herein is not intended to limit the various embodiments of the invention. Terms such as “inclusion,” “contain,” and “include” are not intended to limit them. Furthermore, unless otherwise specified, plural forms are included unless digitized, and “or” and “or” mean “and / or.” Unless otherwise specified herein, all technical and scientific terms used herein have the meanings generally understood by those skilled in the art.

[0074] All publications and patents referenced herein are incorporated by reference to the present invention. Various modifications and changes made to the methods and compositions described herein without departing from the scope and spirit of the present invention will be apparent to those skilled in the art. Although the present invention has been described through specific preferred embodiments, it should be understood that it is inappropriate to interpret the claimed invention as being limited to these specific embodiments. In fact, various modifications that are obvious to those skilled in the art for carrying out the forms described herein are intended to be covered by the appended claims.

Claims

【Request Item 1】 【Chemistry 1】 A method for producing an auristatin derivative intermediate which is a compound represented by the above formula (I), or its enantiomer, racemate, or a pharmaceutically acceptable salt thereof, The manufacturing process is as follows: 【Chemistry 2】 [In the formula, R １ , ８ , １ , ８ , ８ , １ , R ２ , R ３ are independently selected from the group consisting of H, C １ -C ８ alkyl group, C １ -C ８ heteroalkyl group, C ２ -C ８ alkenyl group, C ２ -C ８ alkynyl group, C ３ -C ８ heterocyclic ring, C ３ -C ８ carbocyclic ring, aryl group, C １ -C ８ alkaryl group, C １ -C ８ alkylcarbocyclic ring, and C １ -C ８ alkylheterocyclic ring, and are selected from the group consisting of R ４ is an amino protecting group, R ５ is O or S, R ６ H, -OH, C １ -C ８ alkyl group, C ３ -C ８ Selected from the group consisting of a carbon ring and -O-(C1-C8 alkyl group). Step 1 involves dissolving compound a in one or more appropriate amounts of organic solvent 1 selected from the group consisting of N,N-dimethylformamide, N-methylpyrrolidone, methanol, ethanol, isopropanol, acetonitrile, acetone, tetrahydrofuran, and 1,4-dioxane. Step 2 involves adding an aqueous solution of an inorganic base to the solution formed in step 1 and allowing it to react. A method for producing an auristatin derivative intermediate, comprising step 3, which involves post-treating the reaction system formed in step 2 to obtain a compound represented by formula (I) above.

2. The aforementioned R ４ The manufacturing method according to claim 1, characterized in that the protecting group is selected from the group consisting of a Boc protecting group, a Cbz protecting group, an Fmoc protecting group, and a benzyl protecting group. 【Request Item 3】 【Chemistry 3】 The manufacturing method according to claim 1, characterized in that the compound a has one structure selected from the above. 【Request Item 4】 【Chemistry 4】 The method for producing a compound according to formula (I), characterized in that the compound represented by formula (I) has the above-described structure.

5. The manufacturing method according to claim 1, characterized in that the organic solvent 1 is methanol or ethanol.

6. The manufacturing method according to claim 1, characterized in that the inorganic base in step 2 is selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, potassium carbonate, cesium carbonate, and sodium carbonate.

7. The mass fraction of the inorganic base aqueous solution is 2% to 15%, preferably 3% to 10%; Preferably, the weight-to-volume ratio (g / ml) of compound a to organic solvent 1 is W 化合物ａ :W 有機溶媒１ = 1:3 to 30, and more preferably, the weight-to-volume ratio (g / ml) of compound a to organic solvent 1 is W 化合物ａ :W 有機溶媒１ The manufacturing method according to claim 1, characterized in that the ratio is 1:3 to 14.

8. The molar ratio of compound a to the inorganic base is 1:1 to 10. Preferably, the manufacturing method according to claim 1, characterized in that the molar ratio of compound a to inorganic base is 1:1 to 5.

9. The reaction in step 2 is carried out at -10 to 78°C. Preferably, the reaction is carried out at 5 to 40°C. The manufacturing method according to claim 1, more preferably characterized in that the reaction is carried out at 15 to 35°C.

10. The manufacturing method according to claim 1, characterized in that the post-treatment in step 3 is performed after adjusting the reaction system formed in step 2 to an acidic state.

11. The post-processing in step 3 includes an extraction process and a crystallization process. Preferably, the extraction solvent used in the extraction process is one or more selected from the group consisting of ethyl acetate, dichloromethane, methyl tert-butyl ether, isopropyl acetate, and 2-methyltetrahydrofuran. Preferably, the crystallization solvent used in the crystallization process is one or more selected from the group consisting of N,N-dimethylformamide, N-methylpyrrolidone, methanol, ethanol, isopropyl alcohol, acetonitrile, acetone, 1,4-dioxane, ethyl acetate, dichloromethane, isopropyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, methyl tert-butyl ether, n-hexane, n-heptane, cyclohexane, and methylcyclopentane, as described in claim 1.

12. The crystallization process is carried out at a target temperature of -25 to 60°C. Preferably, the crystallization process is carried out at a target temperature of -10 to 40°C. The manufacturing method according to claim 11, more preferably characterized in that the crystallization process is carried out at a target temperature of 0 to 10°C.

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