A method for preparing a cyclopenta[b]indole compound

Abstract

The application belongs to the technical field of materials, and particularly relates to a preparation method of a cyclopent[B]indole compound. The application provides a preparation method of (R)-2-(7-hydroxy-1,2,3,4-tetrahydrocyclopent[B]indol-3-yl)acetic acid. The method has the advantages of easy-to-obtain raw materials, simple process, convenient operation, mild reaction condition, short reaction time, high-purity (R)-2-(7-hydroxy-1,2,3,4-tetrahydrocyclopent[B]indol-3-yl)acetic acid and high yield, and provides a breakthrough solution for industrialized production of cyclopentindole compounds.

Description

Technical Field

[0001] This invention belongs to the field of biotechnology, and specifically relates to a method for preparing cyclopentyl[B]indole compounds. Background Technology

[0002] Cyclopentaindo compounds have attracted considerable attention in medicinal chemistry in recent years due to their unique rigid structure and broad range of biological activities. These compounds often act as serotonin receptor modulators, dopamine receptor ligands, or neuroprotective agents, showing potential in the treatment of depression, anxiety, and neurodegenerative diseases. In particular, hydroxyl-substituted cyclopentaindo derivatives, with their balanced molecular polarity and blood-brain barrier penetration, offer a superior framework for the development of drugs targeting the central nervous system.

[0003] In the prior art, research on cyclopentaindole compounds mainly focuses on substituent modification of the parent nucleus and stereoisomer control, and preparation methods have also been reported. For example, patent CN200980137275.7 describes obtaining two enantiomers of cyclopentaindole compounds through chiral resolution, but this method has problems such as complex operation and high cost.

[0004] Current preparation methods mostly involve first obtaining the racemic compound of the final product, followed by resolution and purification. This not only increases production costs and operational complexity but also presents limitations for large-scale production. Furthermore, some synthetic routes are lengthy, resulting in low overall yields and high production costs, which is unfavorable for industrial production. In addition, the use of expensive metal catalysts, such as palladium on carbon, in some methods also restricts their widespread application.

[0005] Therefore, developing a method that is simple in reaction steps, mild in conditions, environmentally friendly, and efficient in preparing high-purity cyclopentaneindole intermediates has become a key breakthrough for improving the synthesis technology of this type of compound and promoting its pharmaceutical application. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing (R)-2-(7-hydroxy-1,2,3,4-tetrahydrocyclopentane[B]indole-3-yl)acetic acid with readily available raw materials, simple process, convenient operation, mild reaction conditions, and short reaction time, which can achieve high purity and high yield. This provides a breakthrough solution for the industrial production of cyclopentaneindole compounds.

[0007] On one hand, the present invention provides a method for preparing (R)-2-(7-hydroxy-1,2,3,4-tetrahydrocyclopenta[B]indol-3-yl)acetic acid as shown in formula (II).

[0008]

[0009] Compound (I-1) forms compound (II) in the presence of lipase, enzymatic hydrolysis solvent and pH adjuster.

[0010] In this invention, R 1 It can be selected from alkyl, alkenyl, alkynyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heterocyclic groups;

[0011] Preferably, R 1 It is selected from C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, 3-10 membered cycloalkyl, 6-12 membered aryl, 6-12 membered arylalkyl, 5-12 membered heteroaryl or 3-12 membered heterocyclic.

[0012] In an embodiment of the present invention, R 1 It is selected from C1-C6 alkyl, 3-6 membered cycloalkyl, C2-C4 alkenyl, phenyl or benzyl.

[0013] In one embodiment of the present invention, R 1 It is an ethyl group.

[0014] In one embodiment of the present invention, the structure of the compound of formula (I-1) is further shown as in formula (I):

[0015]

[0016] On the other hand, the present invention provides a method for preparing (R)-2-(7-hydroxy-1,2,3,4-tetrahydrocyclopentan[B]indol-3-yl)acetic acid as shown in formula (II).

[0017]

[0018] Compound (I) forms compound (II) in the presence of lipase, enzymatic hydrolysis solvent and pH adjuster.

[0019] In a preferred embodiment of the present invention, the lipase is selected from one or more of the following: Candida antarcticis lipase B and its crude enzyme solution, Pseudomonas phloxera lipase, Mucor lipase, porcine pancreatic lipase, Pseudomonas fluorescens, and triglyceride lipase.

[0020] In a further preferred embodiment of the present invention, the lipase is Candida antarcticis lipase B.

[0021] In one embodiment of the present invention, the lipase is Candida antarcticis immobilized lipase B.

[0022] In a further preferred embodiment of the present invention, the weight ratio of lipase to compound of formula (I) is 0.5–20.0%; preferably 1.0–10.0%; more preferably 1.0–7.0%; more preferably 1.0–6.0%; and even more preferably 2.0–6.0%.

[0023] In one embodiment of the present invention, the weight ratio of lipase to compound of formula (I) is 3.0%.

[0024] In a preferred embodiment of the present invention, the enzymatic hydrolysis solvent is selected from one or more of ethanol, isopropanol, 1,4-dioxane, acetone, tetrahydrofuran, and acetonitrile; preferably, the enzymatic hydrolysis solvent is selected from one or more of ethanol, 1,4-dioxane, and acetonitrile.

[0025] In one embodiment of the present invention, the enzymatic hydrolysis solvent is selected from acetonitrile.

[0026] In a preferred embodiment of the present invention, the pH adjuster adjusts the pH value to 5.0 to 9.0; preferably 5.8 to 8.6.

[0027] In a further preferred embodiment of the present invention, the pH adjuster adjusts the pH value to 7.8 ± 0.2.

[0028] In a preferred embodiment of the present invention, the pH adjuster is selected from one or more of sodium phosphate buffer, potassium phosphate buffer, disodium hydrogen phosphate-citric acid buffer, acetate-sodium acetate buffer, boric acid-borax buffer, and HEPES buffer; preferably, the pH adjuster is selected from one or more of sodium phosphate buffer, potassium phosphate buffer, disodium hydrogen phosphate-citric acid buffer, and HEPES buffer.

[0029] In one embodiment of the present invention, the pH adjuster is a potassium phosphate buffer solution.

[0030] In a further preferred embodiment of the present invention, the total solvent amount to the volume-to-weight ratio of the compound of formula (I) is 7.0 to 20.0; preferably 7.0 to 15.0; more preferably 7.0 to 10.0; further preferably 7.0 to 9.0; even more preferably 8.0 to 9.0; the total solvent amount is the amount of enzymatic hydrolysis solvent and pH adjuster.

[0031] In one embodiment of the present invention, the total solvent amount is 9.0 times the volume weight of the compound of formula (I).

[0032] In a further preferred embodiment of the present invention, the pH adjuster accounts for 8.0-15.0% of the total solvent; preferably 10.0-12.0%; more preferably 10.5-11.5%.

[0033] In one embodiment of the present invention, the pH adjuster accounts for 11.0% of the total solvent.

[0034] In a preferred embodiment of the present invention, the reaction temperature of the enzymatic hydrolysis reaction is 10–50°C.

[0035] In a preferred embodiment of the present invention, the reaction temperature of the enzymatic hydrolysis reaction is 20–40°C.

[0036] In one embodiment of the present invention, the reaction temperature of the enzymatic hydrolysis reaction is 25±3℃.

[0037] In a preferred embodiment of the present invention, the reaction time of the enzymatic hydrolysis reaction is 0.5 to 24 hours.

[0038] In a preferred embodiment of the present invention, the reaction time of the enzymatic hydrolysis reaction is 2 to 4 hours.

[0039] In a further preferred embodiment of the present invention, post-treatment is further included after the enzymatic hydrolysis reaction is completed.

[0040] In a further preferred embodiment of the present invention, the post-processing includes the following steps: filtration, rinsing, separation, pH adjustment, extraction, and concentration.

[0041] In a further preferred embodiment of the present invention, the post-processing includes the following steps:

[0042] (1) Filtration: Filtration yields filter cake and filtrate;

[0043] (2) Washing: The filter cake is washed with an organic solvent;

[0044] (3) Separation: Transfer the filtrate to the reaction vessel, add alkali, stir, add extractant to extract and separate the aqueous phase;

[0045] (4) pH adjustment: At 20-30℃, add acid to the aqueous phase to adjust the pH value to 3.0-6.0;

[0046] (5) Extraction: The organic phases were extracted multiple times with the extractant, and then washed with salt solution.

[0047] (6) Concentration: The organic phase is concentrated to remove the organic solvent and obtain a solid product.

[0048] In a preferred embodiment of the present invention, the organic solvent in step (2) is selected from one or more of diethyl ether, ethyl acetate, acetonitrile, methanol, ethanol, acetone, tetrahydrofuran, dimethyl sulfoxide and dichloromethane.

[0049] In one embodiment of the present invention, the organic solvent in step (2) is acetonitrile.

[0050] In a preferred embodiment of the present invention, the alkali in step (3) is selected from one or more of sodium bicarbonate, sodium carbonate and sodium hydroxide.

[0051] In one embodiment of the present invention, the base in step (3) is sodium bicarbonate.

[0052] In a preferred embodiment of the present invention, the extractant in step (3) is selected from one or more of ethyl acetate, diethyl ether, dichloromethane, n-hexane and butyl acetate.

[0053] In one embodiment of the present invention, the extractant in step (3) is ethyl acetate.

[0054] In a preferred embodiment of the present invention, the extractant in step (5) is selected from one or more of ethyl acetate, diethyl ether, dichloromethane, n-hexane and butyl acetate.

[0055] In one embodiment of the present invention, the extractant in step (5) is ethyl acetate.

[0056] In a preferred embodiment of the present invention, the salt solution in step (5) is selected from one or more of sodium chloride solution, sodium sulfate solution and magnesium sulfate solution.

[0057] In one embodiment of the present invention, the salt solution in step (5) is a sodium chloride solution.

[0058] On the other hand, in a preferred embodiment of the present invention, compound (II) undergoes an esterification reaction to generate compound (III-1).

[0059]

[0060] In this invention, R 2 It can be selected from alkyl, alkenyl, alkynyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heterocyclic groups;

[0061] Preferably, R 2 It is selected from C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, 3-10 membered cycloalkyl, 6-12 membered aryl, 6-12 membered arylalkyl, 5-12 membered heteroaryl or 3-12 membered heterocyclic.

[0062] In a preferred embodiment of the present invention, R 2 It is selected from C1-C6 alkyl, 3-6 membered cycloalkyl, C2-C4 alkenyl, phenyl or benzyl.

[0063] In one embodiment of the present invention, R 2 It is an ethyl group.

[0064] In one embodiment of the present invention, the structure of the compound of formula (III-1) is further shown as that of formula (III):

[0065]

[0066] On the other hand, in a preferred embodiment of the present invention, compound (II) undergoes an esterification reaction to generate compound (III).

[0067]

[0068] In this invention, the compound of formula (II) undergoes esterification in an organic solvent and an acid catalyst to generate the compound of formula (III-1) or the compound of formula (III).

[0069] In a preferred embodiment of the present invention, the organic solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, n-pentanol, n-hexanol, cyclohexanol, propenol, benzyl alcohol, dimethyl sulfoxide, chloroform, and acetone.

[0070] In a preferred embodiment of the present invention, the organic solvent is an alcohol solvent.

[0071] In a further preferred embodiment of the present invention, the compound of formula (II) undergoes an esterification reaction in an alcohol solvent and an acid catalyst to generate the compound of formula (III-1) or the compound of formula (III).

[0072] In a preferred embodiment of the present invention, the alcohol solvent is selected from C1-C6 alkyl alcohols; preferably, the alcohol solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, n-pentanol, and n-hexanol.

[0073] In one embodiment of the present invention, the alcohol solvent is ethanol.

[0074] In a preferred embodiment of the present invention, the acid catalyst is selected from protic acids, Lewis acids, or solid acids; preferably, the acid catalyst is selected from one or more of sulfuric acid, hydrochloric acid, phosphoric acid, p-toluenesulfonic acid, boron trifluoride (BF3), and zinc chloride.

[0075] In one embodiment of the present invention, the acid catalyst is sulfuric acid.

[0076] On the one hand, in a preferred embodiment of the present invention, compound (III-1) undergoes a substitution reaction to generate compound (IV-1).

[0077]

[0078] In one embodiment of the present invention, R 2 It is an ethyl group.

[0079] In one embodiment of the present invention, the structure of the compound of formula (IV-1) is further shown as that of formula (IV):

[0080]

[0081] On the other hand, in a preferred embodiment of the present invention, compound (III) undergoes a substitution reaction to generate compound (IV).

[0082]

[0083] In a preferred embodiment of the present invention, the compound of formula (III-1) or the compound of formula (III) undergoes a substitution reaction in base A and a polar solvent to generate the compound of formula (IV-1) or the compound of formula (IV).

[0084] In a preferred embodiment of the present invention, base A is selected from one or more of sodium carbonate, potassium carbonate, cesium carbonate, triethylamine, diisopropylethylamine, pyridine, and potassium tert-butoxide.

[0085] In one embodiment of the present invention, base A is cesium carbonate.

[0086] In a preferred embodiment of the present invention, the polar solvent is selected from one or more of acetonitrile, acetone, 2-butanone, dimethylformamide, dimethylacetamide, and tetrahydrofuran.

[0087] In one embodiment of the present invention, the polar solvent is acetonitrile.

[0088] On the one hand, in a preferred embodiment of the present invention, compound (IV-1) undergoes a hydrolysis reaction to generate compound (V).

[0089]

[0090] On the other hand, in a preferred embodiment of the present invention, compound (IV) undergoes a hydrolysis reaction to generate compound (V).

[0091]

[0092] In a preferred embodiment of the present invention, compound (IV) undergoes a hydrolysis reaction in base B and a hydrolytic solvent to generate compound (V).

[0093] In a preferred embodiment of the present invention, alkali B is selected from one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium carbonate, and sodium carbonate.

[0094] In one embodiment of the present invention, base B is lithium hydroxide.

[0095] In a preferred embodiment of the present invention, the hydrolysis solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, 2-methyltetrahydrofuran, and acetonitrile; preferably, the hydrolysis solvent is selected from one or more of methanol, ethanol, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, and acetonitrile.

[0096] In one embodiment of the present invention, the hydrolysis solvent is tetrahydrofuran.

[0097] In a preferred embodiment of the present invention, the compound of formula (V) forms a salt to generate the compound of formula (VI).

[0098]

[0099] On one hand, the present invention provides a method for preparing a compound of formula (VI), comprising the following steps:

[0100]

[0101] Among them, R 1 and R 2 The definition is as described above;

[0102] 1) Compound (I-1) forms compound (II) in the presence of lipase, enzymatic hydrolysis solvent and pH adjuster;

[0103] 2) Compound (II) undergoes esterification in an organic solvent and an acid catalyst to produce compound (III-1);

[0104] 3) Compound (III-1) undergoes a substitution reaction in base A and a polar solvent to produce compound (IV-1);

[0105] 4) Compound (IV-1) undergoes hydrolysis in base B and hydrolytic solvent to produce compound (V);

[0106] 5) Compound (V) forms a salt to generate compound (VI).

[0107] On the other hand, the present invention provides a method for preparing a compound of formula (VI), comprising the following steps:

[0108]

[0109] 1) Compound (I) forms compound (II) in the presence of lipase, enzymatic hydrolysis solvent and pH adjuster;

[0110] 2) Compound (II) undergoes esterification in an alcohol solvent and an acid catalyst to produce compound (III);

[0111] 3) Compound (III) undergoes a substitution reaction in base A and a polar solvent to produce compound (IV);

[0112] 4) Compound (IV) undergoes hydrolysis in base B and hydrolytic solvent to produce compound (V);

[0113] 5) Compound (V) forms a salt to generate compound (VI).

[0114] In this invention, the reaction conditions for each step of the preparation method of compound (VI) are as described above.

[0115] Advantages and effects of the present invention:

[0116] 1) This invention reacts in a near-room temperature environment, requires less enzyme, is easy to operate and less difficult, saves energy and reduces production costs, which is conducive to large-scale and continuous production; it avoids the safety hazards that may be caused by high-temperature operation and also reduces potential risks such as nitrogen leakage, making it more environmentally friendly.

[0117] 2) The reaction time of this invention is shorter, which significantly improves production efficiency and output within the same unit time compared with the prior art, while greatly reducing energy and labor costs. Using (R)-2-(7-hydroxy-1,2,3,4-tetrahydrocyclopenta[B]indole-3-yl)acetic acid prepared in this invention as a key intermediate to further synthesize cyclopentaindole compounds can yield a final product with higher purity and lower levels of impurities such as proteins, DNA, and isomers. This significantly improves the quality attributes of the drug (such as chemical purity, chiral purity, and content of potential genotoxic impurities), providing a safer active pharmaceutical ingredient that is more in line with ICH guidelines for subsequent formulation development.

[0118] 3) Once the ee value exceeds 95%, each 0.1% increase requires significant effort. Improving the ee value necessitates strict control of impurities in the reaction; even trace amounts of impurities can affect the enantioselectivity of the product, thereby impacting efficacy, toxicity, or pharmacokinetics. The preparation method of this invention significantly improves the ee value of the product to over 98%, or even over 99%.

[0119] Relevant definitions:

[0120] Unless otherwise specified, the following terms used in the specification and claims shall have the following meanings:

[0121] "alkyl" refers to a saturated aliphatic hydrocarbon group, including straight-chain or branched saturated hydrocarbon groups having the indicated number of carbon atoms; preferably C1-C12 alkyl; more preferably C1-C6 alkyl. "C1-C6 alkyl" includes C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, and C6 alkyl, examples of which include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, 2-pentyl, 3-pentyl, n-hexyl, 2-hexyl, 3-hexyl, etc.

[0122] "Alkenyl" refers to a straight-chain or branched group that may have a carbon-carbon double bond (C=C) at any position; preferably C2-C12 alkenyl; more preferably C2-C8 alkenyl; and even more preferably C2-C4 alkenyl. "C2-C8 alkenyl" refers to a straight-chain or branched group with 2-8 carbon atoms that may have a carbon-carbon double bond (C=C) at any position, examples of which include, but are not limited to, vinyl, propenyl, allyl, and but-2-en-1-yl.

[0123] "Alynyl" refers to a straight-chain or branched group that may have a triple bond at any position; preferably C2-C12 alkynyl; more preferably C2-C10 alkynyl. "C2-C10 alkynyl" refers to a straight-chain or branched group with 2-10 carbon atoms that may have a triple bond at any position, examples of which include, but are not limited to, ethynyl, propynyl, propynyl, but-2-yn-1-yl, and pent-3-yn-1-yl.

[0124] "Cycloalkyl" refers to a monocyclic saturated hydrocarbon system without heteroatoms or double bonds; preferably a 3-12 membered cycloalkyl; more preferably a 3-10 membered cycloalkyl; and even more preferably a 3-6 membered cycloalkyl. The term "3-10 membered cycloalkyl" refers to a system containing 3 to 10 ring atoms. Examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0125] "Aryl" refers to an aromatic ring group consisting of a single carbon ring or a fused polycyclic aromatic ring with a conjugated π-electron system, obtained by removing a hydrogen atom from a single carbon atom of the parent aromatic ring system; preferably a 6-12-membered aryl; more preferably a 6-8-membered aryl. The term "6-8-membered aryl" means having 6-8 carbon atoms. This includes bicyclic groups comprising an aromatic ring fused with a saturated, partially unsaturated, or aromatic carbon ring. Examples include, but are not limited to, phenyl, naphthyl, anthracene, indene, indane, 1,2-dihydronaphthalene, and 1,2,3,4-tetrahydronaphthalene.

[0126] "Aryl group" refers to an aryl-alkyl group, where the bond to the parent moiety is via an alkyl group, wherein both the aryl and alkyl groups are as described above. Preferred aryl groups comprise lower alkyl groups; more preferably, 6-12-membered aryl groups. Examples include, but are not limited to, benzyl, 2-phenylethyl, and naphthylmethyl.

[0127] "Heteroaryl" refers to an aryl structure containing at least one heteroatom independently selected from N, O, and S, which substitutes for a portion of the carbon atom to form an aromatic cyclic structure. Heteroaryl groups can be monocyclic or polycyclic fused; preferably 5-12 membered heteroaryl groups; more preferably 5-8 membered heteroaryl groups. Examples of heteroaryl groups include, but are not limited to, pyrroleyl, furanyl, thiopheneyl, pyridinyl, imidazolyl, pyrimidinyl, pyrazinyl, thiazolyl, quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, imidazopyridyl, benzofuranyl, pyridazinyl, and isoyindolyl.

[0128] "Heterocyclic group" refers to a saturated or partially unsaturated monocyclic or polycyclic hydrocarbon substituent; preferably a 3-12 membered heterocyclic group; more preferably a 3-8 membered heterocyclic group. The term "3-8 membered heterocyclic group" contains 3 to 8 ring atoms, wherein one or more ring atoms are heteroatoms selected from nitrogen, oxygen or S, and the remaining ring atoms are carbon, preferably 1 to 3 of which are heteroatoms.

[0129] HEPES buffer: (4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid) buffer.

[0130] Volumetric mass ratio: v / m.

[0131] HPLC: High Performance Liquid Chromatography.

[0132] ee value: Enantiomer excess value, used to measure the degree of excess of one enantiomer relative to another in chiral synthesis. The formula is [(major enantiomer - minor enantiomer) / (major enantiomer + minor enantiomer)] × 100%. The higher the ee value, the higher the enantiomer purity of the product. Detailed Implementation

[0133] The present invention will be further described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of the present invention, not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, the materials, reagents, etc. used in the following embodiments are commercially available.

[0134] Example 1

[0135] Add 1602 mL of acetonitrile and 200.00 g of ethyl 2-(7-hydroxy-1,2,3,4-tetrahydrocyclopentanol[B]indol-3-yl) to a 2 L three-necked flask sequentially. Maintain the temperature at 25 ± 3 °C, and add 198 mL of buffer solution (adjusting the pH to 7.8 ± 0.2) while stirring. Stir for 5–15 min. Add 6 g of *Candida antarctica* immobilized lipase B, maintain the temperature at 25 ± 3 °C, and stir for 2–4 h. Take a sample (1 drop, dilute with an appropriate amount of methanol, and filter). Monitor the reaction progress by HPLC. After the reaction is complete, filter, wash the filter cake with 200 mL of acetonitrile, collect the filtrate, add 1.6 L of 2% sodium bicarbonate solution, and stir for 5–15 min. Add 1.6 L of ethyl acetate and separate the aqueous phase. Adjust the pH to 3.0–6.0 with 1 M citric acid at 20–30 °C, then extract twice with 1 L × 2 ethyl acetate. Combine the organic phases and wash with an appropriate amount of saturated sodium chloride solution. The organic solvent was removed by concentration to give 75.1 g of a white solid of compound (II), with a purity of 99.4%, a single impurity of 0.08%, an ee value of 99.1%, and a yield of 42.8%.

[0136] HPLC analysis conditions: Mobile phase A: Mobile phase B (0.1% phosphoric acid solution: acetonitrile); Column: Agilent Poroshell 120EC-C18, 4.6 mm × 150 mm, 2.7 μm or equivalent column; Flow rate: 1.0 mL / min; Detection wavelength: 230 nm; Column temperature: 35 °C; Elution gradient:

[0137] Time (minutes) Mobile phase A (%) Mobile phase B (%) 0 90 10 15 10 90 20 10 90 20.01 90 10 30 90 10 .

[0138] The following Examples 2-5 were prepared with reference to Example 1:

[0139] Example 2: Keeping other conditions constant, the solvent type was changed, and the reaction results are as follows:

[0140] Table 1

[0141]

[0142] Example 3: Keeping other conditions constant, but changing the total solvent amount, the reaction results are as follows:

[0143] Table 2

[0144]

[0145] v / m: Total solvent volume to substrate weight ratio

[0146] Example 4: Keeping other conditions constant, the proportion of buffer solution in the total solvent (buffer solution and solvent) was changed, and the reaction results are as follows:

[0147] Table 3

[0148]

[0149]

[0150] Example 5: Keeping other conditions constant, the reaction temperature was changed, and the reaction results are as follows:

[0151] Table 4

[0152]

[0153] Example 6

[0154] 104.0 g of compound (II) prepared in Example 1 and 312 mL of anhydrous ethanol were added to a 1 L three-necked flask. 26.5 g of concentrated sulfuric acid was added with stirring, and the mixture was refluxed at 80 °C for 6 h. The reaction was monitored by HPLC until complete. The reaction solution was cooled to room temperature, and 624 mL of purified water was added. The temperature was controlled at 20-30 °C, and saturated sodium carbonate solution was slowly added to adjust the pH to 7-8. Then, 624 mL of ethyl acetate was added, and the mixture was allowed to stand and separated. The organic phase was separated, and the aqueous phase was extracted once again with 312 mL of ethyl acetate. The combined organic phases were washed with an appropriate amount of saturated NaCl aqueous solution and concentrated in a water bath at 40-50 °C to obtain 81.6 g of compound (III), with a yield of 70%.

[0155] Example 7

[0156] 100 g of compound (III) and 1 L of acetonitrile were added to a 2 L three-necked flask. While stirring, 163.3 g of Cs₂CO₃ and 111.4 g of 4-chloromethyl-1-cyclopentyl-2-trifluoromethylbenzene were added, and the mixture was purged with nitrogen three times. The mixture was heated to 65-75 °C and reacted for 4 h, with HPLC monitoring to ensure complete reaction. The mixture was cooled to 20-30 °C, filtered, and the filter cake was washed with 200 mL of acetonitrile. The combined filtrates were concentrated to obtain an oily substance. 1 L of methyl tert-butyl ether was added to the oily substance, stirred to dissolve, and washed with 1 L of purified water. The organic phase was collected and concentrated to dryness in a water bath at 40-50 °C to obtain 177.9 g of compound (IV), with a yield of 95%.

[0157] Example 8

[0158] 55.0 g of compound (IV) and 550 mL of tetrahydrofuran were added to a 1 L three-necked flask. The mixture was stirred, and a solution of 7.1 g of lithium hydroxide and 220 mL of purified water was slowly added dropwise while maintaining the temperature at 20–30 °C. After the addition was complete, the reaction was continued at this temperature for 6–7 h, and the reaction was monitored by HPLC until complete. 550 mL of purified water was added to the reaction mixture, and the pH was adjusted to 6–7 with 2N hydrochloric acid while stirring. Then, 1.1 L of ethyl acetate was added, and the organic phase was separated. The aqueous phase was extracted once again with 550 mL of ethyl acetate. The combined organic phases were washed with an appropriate amount of saturated NaCl solution and concentrated at 40–50 °C to obtain an oily substance. This oily substance was slurried in a mixture of 55 mL of ethyl acetate and 275 mL of heptane at 0 °C for 3 h. The mixture was filtered, and the filter cake was dried under reduced pressure at 40–50 °C to obtain 49.8 g of compound (V), with a yield of 96%.

[0159] Example 9

[0160] 40.0 g of compound (V) and 480 mL of isopropanol were added to a 1 L three-necked flask. The mixture was heated to 70–80 °C and stirred until dissolved. A solution of 15.2 g of L-arginine in water (40 mL) was slowly added dropwise, and stirring was continued at this temperature for 0.5 h. Then, the temperature was slowly lowered to 20–30 °C to allow crystals to crystallize for 2 h. The mixture was filtered, and the filter cake was washed with 80 mL of isopropanol. The solid was dried under reduced pressure at 40–50 °C to give 44.2 g of compound (VI), with a yield of 80%, a purity of 99.89%, and an ee value of 99.76%.

Claims

1. A method for preparing a compound of formula (II), characterized in that, Compound (I-1) forms compound (II) in the presence of lipase, enzymatic hydrolysis solvent, and pH adjuster. Among them, R 1 Selected from alkyl, alkenyl, ynyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heterocyclic groups; preferably, R 1 Selected from C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, 3-10 membered cycloalkyl, 6-12 membered aryl, 6-12 membered arylalkyl, 5-12 membered heteroaryl or 3-12 membered heterocyclic; more preferably, R 1 Selected from C1-C6 alkyl, 3-6 membered cycloalkyl, C2-C4 alkenyl, phenyl or benzyl; more preferably, R 1 It is ethyl; More preferably, Compound (I) forms compound (II) in the presence of lipase, enzymatic hydrolysis solvent and pH adjuster.

2. The preparation method according to claim 1, characterized in that, The lipase is selected from one or more of the following: Candida antarcticis lipase B and its crude enzyme solution, Saccharomyces phagnum lipase, Mucor miltiorrhiza lipase, porcine pancreatic lipase, Pseudomonas fluorescens and triglyceride lipase; preferably, the lipase is Candida antarcticis lipase B. And / or, the weight ratio of lipase to compound of formula (I) is 0.5 to 20.0%; preferably 1.0 to 10.0%; more preferably 1.0 to 7.0%; even more preferably 1.0 to 6.0%; and even more preferably 2.0 to 6.0%.

3. The preparation method according to claim 1, characterized in that, The enzymatic hydrolysis solvent is selected from one or more of ethanol, isopropanol, 1,4-dioxane, acetone, tetrahydrofuran, and acetonitrile; preferably, the enzymatic hydrolysis solvent is selected from one or more of ethanol, 1,4-dioxane, and acetonitrile; more preferably, the enzymatic hydrolysis solvent is acetonitrile.

4. The preparation method according to claim 1, characterized in that, The pH adjuster adjusts the pH value to 5.0–9.0; preferably 5.8–8.6; more preferably, the pH adjuster adjusts the pH value to 7.8 ± 0.2; And / or, the pH adjuster is selected from one or more of sodium phosphate buffer, potassium phosphate buffer, disodium hydrogen phosphate-citrate buffer, acetate-sodium acetate buffer, boric acid-borax buffer, and HEPES buffer; preferably, the pH adjuster is selected from one or more of sodium phosphate buffer, potassium phosphate buffer, disodium hydrogen phosphate-citrate buffer, and HEPES buffer; more preferably, the pH adjuster is potassium phosphate buffer.

5. The preparation method according to claim 1, characterized in that, The total solvent volume to the compound of formula (I) is 7.0 to 20.0 by volume; preferably 7.0 to 15.0; more preferably 7.0 to 10.0; even more preferably 7.0 to 9.0; and even more preferably 8.0 to 9.0; wherein the total solvent volume is the amount of enzymatic hydrolysis solvent and pH adjuster. And / or, the pH adjuster accounts for 8.0-15.0% of the total solvent; preferably 10.0-12.0%; more preferably 10.5-11.5%; and even more preferably 11.0%. And / or, the reaction temperature of the enzymatic hydrolysis reaction is 10–50°C; preferably, the reaction temperature of the enzymatic hydrolysis reaction is 20–40°C; more preferably, the reaction temperature of the enzymatic hydrolysis reaction is 25±3°C; And / or, the reaction time of the enzymatic hydrolysis reaction is 0.5 to 24 hours; preferably, the reaction time of the enzymatic hydrolysis reaction is 2 to 4 hours.

6. A method for preparing a compound of formula (III-1), characterized in that, The process includes the following steps: the compound of formula (II) as described in any one of claims 1 to 5 undergoes an esterification reaction to generate the compound of formula (III-1). Among them, R 2 Selected from alkyl, alkenyl, ynyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heterocyclic groups; preferably, R 2 Selected from C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, 3-10 membered cycloalkyl, 6-12 membered aryl, 6-12 membered arylalkyl, 5-12 membered heteroaryl or 3-12 membered heterocyclic; more preferably, R 2 Selected from C1-C6 alkyl, 3-6 membered cycloalkyl, C2-C4 alkenyl, phenyl or benzyl; more preferably, R 2 It is ethyl; Preferably, the structure of the compound of formula (III-1) is further as shown in formula (III): Preferably, the compound of formula (II) undergoes esterification in an organic solvent and an acid catalyst to generate the compound of formula (III-1); Preferably, the organic solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, n-pentanol, n-hexanol, cyclohexanol, allyl alcohol, benzyl alcohol, dimethyl sulfoxide, chloroform, and acetone; Preferably, the organic solvent is an alcohol solvent; more preferably, the alcohol solvent is selected from C1-C6 alkyl alcohols; more preferably, the alcohol solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, n-pentanol, and n-hexanol; even more preferably, the alcohol solvent is ethanol. Preferably, the acid catalyst is selected from protic acids, Lewis acids, or solid acids; more preferably, the acid catalyst is selected from one or more of sulfuric acid, hydrochloric acid, phosphoric acid, p-toluenesulfonic acid, boron trifluoride (BF3), and zinc chloride; even more preferably, the acid catalyst is sulfuric acid.

7. A method for preparing a compound of formula (IV-1), characterized in that, The process includes the following steps: the compound of formula (III-1) described in claim 6 undergoes a substitution reaction to generate the compound of formula (IV-1). Among them, R 2 The definition is as described in claim 6; Preferably, the structure of the compound of formula (IV-1) is further as shown in formula (IV): Preferably, the compound of formula (III-1) undergoes a substitution reaction in base A and a polar solvent to generate the compound of formula (IV-1); Preferably, base A is selected from one or more of sodium carbonate, potassium carbonate, cesium carbonate, triethylamine, diisopropylethylamine, pyridine, and potassium tert-butoxide; more preferably, base A is cesium carbonate. Preferably, the polar solvent is selected from one or more of acetonitrile, acetone, 2-butanone, dimethylformamide, dimethylacetamide, and tetrahydrofuran; more preferably, the polar solvent is acetonitrile.

8. A method for preparing a compound of formula (V), characterized in that, The process includes the following steps: the compound of formula (IV-1) described in claim 7 undergoes a hydrolysis reaction to generate the compound of formula (V). Among them, R 2 The definition is as described in claim 6; Preferably, the compound of formula (IV-1) undergoes a hydrolysis reaction in base B and a hydrolytic solvent to generate the compound of formula (V); Preferably, base B is selected from one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium carbonate, and sodium carbonate; more preferably, base B is lithium hydroxide. Preferably, the hydrolysis solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, 2-methyltetrahydrofuran, and acetonitrile; more preferably, the hydrolysis solvent is selected from one or more of methanol, ethanol, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, and acetonitrile; even more preferably, the hydrolysis solvent is tetrahydrofuran.

9. A method for preparing a compound of formula (VI), characterized in that, The steps include: salt formation of the compound of formula (V) as described in claim 8 to generate the compound of formula (VI), 10. A method for preparing a compound of formula (VI), characterized in that, Includes the following steps: Among them, R 1 and R 2 The definition is as described in claim 1 or 6; 1) Compound (I-1) forms compound (II) in the presence of lipase, enzymatic hydrolysis solvent and pH adjuster; 2) Compound (II) undergoes esterification in an organic solvent and an acid catalyst to produce compound (III-1); 3) Compound (III-1) undergoes a substitution reaction in base A and a polar solvent to produce compound (IV-1); 4) Compound (IV-1) undergoes hydrolysis in base B and hydrolytic solvent to produce compound (V); 5) Compound (V) forms a salt to generate compound (VI).

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