Method for producing (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid

Abstract

The present invention relates to a method for preparing (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid in anhydrous crystalline form A. The present invention further relates to methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate, an intermediate of the method.

Description

[Technical Field]

[0001] Cross-references to related applications This application claims priority to Polish Patent Application No. P.444342, filed on April 6, 2023, and U.S. Provisional Patent Application No. 63 / 494,557, filed on April 6, 2023.

[0002] The present invention relates to a method for preparing (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid in anhydrous crystalline form A. The present invention further relates to methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate, which is an intermediate in this method. [Background technology]

[0003] The (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]-cyclohexane-1-carboxylic acid of structural formula 1 is described in International Publication No. 2017 / 191130, U.S. Patent No. 10,391,077, and Example 38 of U.S. Patent No. 10,912,755. All of these documents claim priority to Polish Patent Application No. P-417066 filed on May 4, 2016, U.S. Provisional Patent Application No. 62 / 331,550 filed on May 4, 2016, and U.S. Provisional Patent Application No. 62 / 444,669 filed on January 10, 2017. The disclosures of these documents are incorporated herein by reference in their entirety.

[0004] JPEG2026513909000001.jpg3151

[0005] The compound of formula 1 is a dual inhibitor of both the ARG1 and ARG2 enzymes. Such compounds can be used to treat disorders associated with the overexpression of these enzymes. Associated disorders include, for example, colorectal cancer, ovarian cancer, renal cell carcinoma, pancreatic ductal adenocarcinoma, and acute myeloid leukemia.

[0006] Further treatable disorders, diseases, or conditions include cardiovascular disorders, sexual disorders, wound healing disorders, gastrointestinal disorders, autoimmune disorders, immune disorders, human immunodeficiency virus (HIV) infection, hepatitis B virus (HBV) infection, hepatitis C virus (HCV) infection, Helicobacter pylori infection, lung disorders, hemolytic disorders, and neoplasms.

[0007] Neoplasms are cancers selected from the group consisting of gastric cancer, colorectal cancer, pancreatic cancer, liver cancer, breast cancer, lung cancer, renal cell carcinoma, prostate cancer, multiple myeloma, acute and chronic leukemia, T-cell, B-cell, and NK-cell lymphoma, brain tumors, head and neck squamous cell carcinoma, and melanoma.

[0008] The aforementioned international publications and US patent documents describe the synthesis of the compound of formula 1 from ethyl(4R)-2-hydroxy-4-vinylcyclohexa-1-ene-1-carboxylate of formula 2. This synthesis is outlined in Scheme 1 below.

[0009] JPEG2026513909000002.jpg5697

[0010] The compound of formula 2 is reacted with ammonium acetate and tert-butyl isocyanide in 2,2,2-trifluoroethanol at ambient temperature. After stirring overnight, crude product 3 and its diastereoisomers are isolated by extraction, and the main diastereoisomer 3 is purified by column chromatography. Then, pure ethyl (1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-vinylcyclohexane-1-carboxylate 3 is reacted with 1M DIBAL-H in DCM, glacial acetic acid, a 2M solution of dimethylamine in THF, and sodium triacetoxyborohydride to obtain crude (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-vinylcyclohexane-carboxamide of formula 4. The crude product is purified by column chromatography to obtain the corresponding product as a single diastereoisomer. In the next synthetic step, pure 4 is converted to (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide of formula 5 using 1,2-bis(diphenylphosphin)ethane, bis(1,5-cyclooctadiene)diiridium(I) dichloride, and 4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide of formula 5. Purification by column chromatography yields pure product 5. Finally, the compound of formula 5 is subjected to deprotection reactions of the amine, carboxylic acid, and boronic acid moieties. In this step, 6M HCl and reflux are applied, and the crude product obtained as hydrochloride is then desalted using DOWEX® 50WX8 with 0.1M ammonia in water as the eluent. The desired product 1 is obtained as a white solid.

[0011] The synthesis of the compound of formula 1 presented above requires at least three chromatographic purifications. This isolation method requires a large amount of solvent, takes time, and cannot be considered suitable for large-scale production. Furthermore, in the penultimate step, bis(1,5-cyclooctadiene)diiridium(I) dichloride, a heavy metal-based catalyst, is used, which may cause the problem of iridium residue in the final substance. There is no information regarding whether product 1 can be obtained in a crystalline form. The above characteristics suggest that the presented method cannot be considered efficient and scalable.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Non-Patent Documents

[0013]

Non-Patent Document 1

[0014] The present invention provides a method for preparing methyl (1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)-cyclohexane-1-carboxylate in a solid crystalline state of formula 11.

[0015] The present invention provides an industrially scalable method for preparing (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid of formula 1. This method avoids the use of heavy metal-based catalysts and involves only one filtration by silica gel column chromatography. The final product is obtained in a reproducible manner in terms of polymorphic form, purity, and chiral purity, meeting high standards for pharmaceutical substances.

[0016] The present invention provides a method for preparing a solid crystalline compound of formula 1 in anhydrous form A.

[0017] The present invention relates to a solid crystalline (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid of formula 1 in anhydrous form A, which is characterized by at least one of the following. (i) XRPD peaks: 7.39, 8.55, 9.49, 12.83, 14.71, 16.86, 17.37, 17.88, 19.11, 19.88, 20.55, 21.19, 22.18, 22.87, 23.66, 24.52, 25.73, 26.09, 26.94, 28.19, 28.61, 28.88, 29.69, 30.28, 31.45, 32.02, 33.06, 33.36, 34.05, 34.52, 35.15, 36.20, 37.52, 38.95, 40.54, 41.76; (ii) IR bands: 3134, 2992, 2918, 2859, 2826, 2789, 2764, 2727, 1584, 1522, 1458, 1404, 1369, 1344, 1310, 1263, 1202, 1159, 1105, 1074, 1028, 993, 887, 845, 762, 731 cm -1 ; (iii) DSC traces showing two broad endothermic events, one starting at 141.9°C and peaking at 173.7°C, and the other starting at 237.4°C and peaking at 254.1°C.

[0018] The characteristics described above are substantially consistent with those shown in Figures 1-3. [Brief explanation of the drawing]

[0019] [Figure 1] This is the XRPD diffractogram of (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid in its anhydrous form A. [Figure 2] This is the FT-IR (ATR) spectrum of (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid in its anhydrous form A. [Figure 3] This is a DSC thermogram of (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid in its anhydrous form A. [Figure 4]This is the 1H NMR (D2O, 400MHz) spectrum of (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid. [Figure 5] This is the 13C NMR (D2O, 100 MHz) spectrum of (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid. [Modes for carrying out the invention]

[0020] This specification provides an efficient and scalable synthesis of methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-ethyl)cyclohexane-1-carboxylate of formula 11. This compound has not yet been isolated or described at all.

[0021] The compound of formula 6 was prepared according to the protocol in the literature (Jiricek, J.; Blechert, S. Enantioselective Synthesis of (-)-Gilbertine via a Cationic Cascade Cyclization. J.Am.Chem.Soc. 2004, Vol. 126, pp. 3534-3538). Compound 6 was reacted with bromine and triphenylphosphine at room temperature in a solvent, preferably in the presence of an organic base in DCM, preferably pyridine. Imidazole can also be used as the organic base. After complete conversion of the substrates, the reaction was quenched by adding an alcohol, preferably methanol. Crude compound 7 was washed with water, followed by washing with a weak base, preferably NaHCO3 and Na2S2O3, and isolated by precipitation of triphenylphosphine using a nonpolar solvent, preferably an alkane, more preferably n-hexane. After evaporation of the solvent, crude compound 7 was used in the next step without any further purification.

[0022] The resulting substance of formula 7 is dissolved in a solvent, preferably acetonitrile, and an aqueous HCl solution is added at ambient temperature. After complete conversion of the substrate, the solvent is removed under vacuum, and the aqueous phase is extracted with a solvent, preferably ether, more preferably MTBE. The organic phase is washed with a weak base, preferably a saturated aqueous NaHCO3 solution, and brine. After evaporating the solvent, the crude compound 8 is used in the next step without any further purification.

[0023] In the next step, crude compound 8 in a solvent, preferably DMF, is added at ambient temperature to a mixture of Ph3P, B2(pin)2, CuI, and MeOLi suspended in a solvent, preferably DMF. The reaction was carried out at a high temperature, preferably 40°C. Once complete conversion of the substrate was obtained, the solution was filtered through a Celite pad and a solvent, preferably ether, more preferably MTBE, and 1M HCl were added. After phase separation, the aqueous phase was extracted with a solvent, preferably ether, more preferably MTBE, and the organic phase was washed with brine. After evaporation of the solvent, triphenylphosphine was precipitated using a nonpolar solvent, preferably an alkane, more preferably n-hexane. After filtration and solvent evaporation, crude compound 9 was purified by distillation under reduced pressure.

[0024] The compound of formula 9 is reacted with dimethyl carbonate at a high temperature, preferably 75°C, in a solvent, preferably in the presence of a strong base in DMF, preferably sodium hydride (mineral oil-free). Maintaining the aforementioned temperature is crucial, as higher temperatures will cause a decrease in the overall purity of the product. Once the substrate is completely converted, the reaction is quenched with a saturated aqueous NH4Cl solution at ambient temperature. This step is highly exothermic, so the quenching is carried out slowly. The crude compound of formula 10 is isolated by extraction with a solvent, preferably MTBE, and the organic phase is washed with water. After evaporating the solvent, the crude compound 10 is used in the next step without any further purification.

[0025] JPEG2026513909000003.jpg39100

[0026] The substance of formula 10 obtained is dissolved in a solvent, preferably 2,2,2-trifluoroethanol, and ammonium acetate is added at ambient temperature. After the ammonium acetate is completely dissolved, the reaction mixture is cooled to a lower temperature, preferably 0°C, and tert-butyl isocyanide is added. After complete conversion is achieved, the reaction mixture is concentrated under vacuum and evaporated with a nonpolar solvent, preferably an alkane, more preferably n-hexane or n-heptane. To remove excess ammonium acetate and promote crystallization, the resulting suspension is filtered through a short silica gel column. The desired compound is eluted with a solvent, preferably an MTBE / DCM mixture. The fraction containing the product of formula 11 is evaporated to obtain crude compound 11. To remove impurities generated in this step, the crude product is crystallized from a solvent, preferably ether, more preferably i-Pr2O. The main impurities are diastereomers 12, 13, 14, and the diastereomer product of general formula 15 due to Passerini side reactions. To improve the overall yield of this step, the mother liquor may be evaporated and purified by silica gel column chromatography. The obtained substance may be further purified by crystallization in the same manner as described above.

[0027] JPEG2026513909000004.jpg4195

[0028] The present invention further provides a method for synthesizing (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid of formula 1 in anhydrous form A, which is in a solid crystalline state. Compared to the original method outlined in Scheme 1 in the "Background Art" section, various modifications have been introduced to the synthetic procedure to improve yield and purity and enable scaling up.

[0029] Intermediate compound 5 can be prepared by reacting methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)-cyclohexane-1-carboxylate of formula 11 with DIBAL-H (in DCM) at a low temperature, preferably -75°C. Low temperature is important to reduce the amount of excess reduction product of formula 16. In this step, reduction of the carbonyl portion of the amide group also occurs, generating the impurity of formula 17. The reaction mixture is quenched with an organic acid, preferably acetic acid (AcOH). In this step, if AcOH is added directly to the reaction mixture, a large amount of foam is generated. If the addition method is reversed, quenching becomes very fast, and as a result, the amount of impurity of formula 18 generated is reduced. The crude mixture is further reacted with dimethylamine at a low temperature, preferably -75°C. Next, the reaction mixture is slowly heated, preferably to -20°C, and a reducing agent, preferably sodium triacetoxyborohydride, is added. The mixture is quenched with a saturated aqueous sodium carbonate solution and extracted with a solvent, preferably DCM, to obtain the crude (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide of formula 5.

[0030] The above conversion can also be carried out under flow conditions. To do so, a reducing agent, preferably sodium triacetoxyborohydride, is suspended in a solvent, preferably DCM, and cooled to a lower temperature, preferably -75°C. A flow of mixed reagent-11, dimethylamine (in THF), an organic acid, preferably acetic acid, and DIBAL-H (in DCM), cooled to a lower temperature, preferably 0°C, is supplied to the resulting suspension. The reaction mixture is preferably heated to ambient temperature. Quenched with saturated aqueous sodium carbonate solution, filtered through Celite, and extracted with a solvent, preferably DCM, the crude (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide of formula 5 is obtained.

[0031] JPEG2026513909000005.jpg3891

[0032] The reduction amination of the compound of formula 11 generates various impurities. Before the next step, the crude product mixture containing 5 is dissolved in a solvent, preferably ether, more preferably MTBE, and the compound containing the amino moiety is extracted together with the compound of formula 25 into an aqueous layer using 0.5 M HCl. This process results in the formation of the hydrochloride salt 19 from the amino compound 5. Simultaneously, partial deprotection of the boronic acid ester occurs, leading to the formation of deprotected derivatives such as 20, 22, 24, and 25. Significant impurities, such as unreacted substrate 11 and the alcohol of formula 16 (formed as a product of excessive reduction of the carboxylic acid ester moiety), are removed by this extraction.

[0033] JPEG2026513909000006.jpg10093

[0034] In the next step, 12 M HCl is added to the combined aqueous layer from the extraction described above to obtain a final concentration of 6 M HCl. The mixture is then stirred under reflux until (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)-methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide hydrochloride of formula 19 is completely converted to the deprotection target compound 1 in the form of its hydrochloride. Under these conditions, the impurities generated in the previous step are hydrolyzed, yielding new compounds such as 26, 27, and 28. The deprotection alcohol of formula 25 is converted to lactone 29. The reaction mixture is cooled to a lower temperature, preferably ambient temperature, and evaporated under vacuum. The resulting crude mixture containing product 1 in the form of hydrochloride salt is dissolved in H2O and loaded onto an ion-exchange resin column, preferably prepared from DOWEX® 50WX8 and regenerated with 1M HCl. The column is eluted with water until pH=7 is achieved. The product is then eluted with 1M aqueous ammonia. The fractions containing 1 are combined and evaporated to obtain the crude product.

[0035] JPEG2026513909000007.jpg6786

[0036] After the desalting step, the crude mixture is purified by crystallization. For this purpose, the crude mixture is dissolved in a solvent, preferably water, at a high temperature, preferably 50°C. Then, a reverse solvent, preferably acetone, is added at a high temperature, preferably 50°C. The resulting suspension is then cooled to a lower temperature, preferably 0°C. The suspension is filtered, washed with a solvent, preferably acetone, and dried to obtain a white solid with a purity of >97% by HPLC.

[0037] To further improve the purity of this substance, recrystallization is used. For this purpose, the crude product is dissolved in a mixture of solvents, preferably methanol and water, at a high temperature, preferably 65°C. The mixture is then concentrated at a high temperature, preferably 85°C, to about half of the initial volume, and the allocated solvent, preferably acetone, is added. The mixture is concentrated again to half of the initial volume, the allocated solvent, preferably acetone, is added, and this entire operation is repeated one more time. A new allocated solvent, preferably acetone, is added to the resulting mixture, and the resulting suspension is then concentrated to 9 / 10 of the initial volume. The addition of acetone allows the mixture to cool to ambient temperature. The resulting suspension is then cooled to a lower temperature, preferably 0°C. The crystals are filtered and washed with a solvent, preferably acetone. The crystals are collected and dried to obtain the final product of formula 1 as white crystals with a purity of >99% by HPLC.

[0038] During the synthesis of the compound of formula 1, oxidative deboration occurs, thereby producing the alcohol compound (1R,2S,5R)-1-amino-2-[(dimethylamino)methyl]-5-(2-hydroxyethyl)cyclohexane-1-carboxylic acid of formula 30, which is largely removed during the crystallization process described above.

[0039] JPEG2026513909000008.jpg3045 [Examples]

[0040] The present invention will be illustrated by the following examples, which are provided solely for illustrative purposes and are not intended in any way to limit the scope of the invention.

[0041] Abbreviation Abbreviations used in this specification have their usual meanings. ATR - Attenuated Total Reflection B2(pin)2- Bis(Pinacolato) Diboron DCM - Dichloromethane DIBAL-H - Diisobutylaluminum hydride DMF - Dimethylformamide i-Pr2O - Diisopropyl ether MeCN - Acetonitrile MTBE - Methyl tert-butyl ether THF - Tetrahydrofuran.

[0042] Basic Procedure All commercially available solvents, substrates, and reagents were used without further purification.

[0043] NMR spectra were recorded using an Agilent Mercury 400 MHz spectrometer. The NMR spectra were recorded in a commercially available, specified deuterated solvent.

[0044] Resonance is, 1 For 1H NMR, the result is expressed as parts per million relative to the residual solvent (δ4.79 ppm for D2O, δ7.26 ppm for CDCl3), or 13 For 13C NMR, the values ​​are expressed as parts per million relative to the solvent (δ 77.16 ppm for CDCl3). The data are reported as follows: chemical shift (δ), multiplicity (s=singular, d=double, t=tripular, q=quadular, m=multiplex, br=broad), coupling constant (J in Hz), and integral value.

[0045] The FT-IR spectrum was recorded using the ATR mode (zinc selenide crystal) of the Shimadzu IRTracer-100.

[0046] The XPRD diffractogram of compound 1 was recorded using a Bruker D8 Discover powder X-ray diffractometer equipped with CuKα radiation (1.54 Å) and a Vantec detector. The sample was analyzed in continuous mode with a step size of 0.01222276° and a step time of 0.9 seconds over an angular range of 3–50°²θ.

[0047] DSC thermograms were recorded using a Mettler Toledo DSC3 with a gradient of 5°C / min.

[0048] HPLC / UHPLC purity is expressed as the area under the curve in percent.

[0049] Optical rotation was recorded at 20°C and 589 nm using a Perkin Elmer 241 polarimeter.

[0050] The purity of intermediate compound 9 was measured by GC-FID. The analysis was performed using a Phenomenex Zebron ZB-5ms column (Phenomenex Zebron ZB-5ms, 0.25 mm × 30 m × 0.25 μm) with helium as the carrier gas at a flow rate of 1 mL / min. The following oven program was applied: initial temperature 50°C, gradient from 50°C to 310°C (10°C / min), and holding at 310°C for 2 minutes. The injector temperature was 250°C, the injection volume was 1 μL, and the split ratio was 1:50. The FID detector temperature was 300°C, and the FID air flow rate was 400 mL / min. The execution time of this method was 28 minutes.

[0051] The purity of intermediate compounds 11 and 5 was measured by HPLC-UV. Analysis was performed on a Zorbax Extend C18 analytical column (Agilent Zorbax Extend C18, 4.6 mm × 150 mm; 3.5 μm) at 30°C and a mobile phase flow rate of 2 mL / min. The mobile phase was a mixture of solvent A (950 mL water, 50 mL acetonitrile, 840 mg sodium bicarbonate) and solvent B (200 mL water, 800 mL acetonitrile, 840 mg sodium bicarbonate). Elution was performed under gradient conditions (25% solvent B from 0.0 to 4.0 min, then 25% to 100% solvent B from 4.0 to 23.0 min, then 100% solvent B from 23.0 to 24.0 min, then 100% to 25% solvent B from 24.0 to 25.0 min, then 25% solvent B from 25.0 to 33.0 min). The peak is recorded using UV detection at 210 nm.

[0052] The purity of compound 1 was measured by UHPLC-FLD with post-column derivatization. The analysis was performed on an XSelect CSH C18 analytical column (Waters XSelect CSH C18, 3 mm × 100 mm; 2.5 μm) at 30°C and a mobile phase flow rate of 0.5 mL / min. The mobile phase was a mixture of solvent A (1000 mL water, 0.5 g ammonium bicarbonate, pH adjusted to 8.4 with ammonia) and solvent B (200 mL water, 800 mL acetonitrile, 0.5 g ammonium bicarbonate, pH adjusted to 8.4 with ammonia). The derivatization solution was solvent C (1000 mL methanol, 168 mg alizarin) at a flow rate of 0.5 mL / min. Elution is performed under gradient conditions (0% to 6% solvent B from 0.0 to 2.0 mins, then 6% solvent B from 2.0 to 4.0 mins, then 6% to 10% solvent B from 4.0 to 5.0 mins, then 10% solvent B from 5.0 to 9.0 mins, then 10% to 100% solvent B from 9.0 to 18 mins, then 100% to 0% solvent B from 18 to 18.10 mins, then 0% solvent B from 18.10 to 23 mins). Peaks are recorded using a fluorescence detector with excitation at 440 nm and emission at 580 nm.

[0053] The impurity content of Equation 30 was measured by HPLC / UHPLC-UV. The analysis was performed using a Zorbax Extend C18 analytical column (Agilent Zorbax Extend C18, 2.1 mm × 100 mm; 3.5 μm) at 30°C and a mobile phase flow rate of 0.5 mL / min. The mobile phase was a mixture of solvent A (1000 mL water, 840 mg sodium bicarbonate) and solvent B (200 mL water, 800 mL acetonitrile, 840 mg sodium bicarbonate). Elution is performed under gradient conditions (0% to 5% solvent B from 0.0 to 2.0 min, then 5% solvent B from 2.0 to 5.0 min, then 5% to 7% solvent B from 5.0 to 8.0 min, then 7% to 100% solvent B from 8.0 to 20 min, then 100% to 0% solvent B from 20 to 20.10 min, then 0% solvent B from 20.10 to 30 min). Peaks are recorded using UV detection at 210 nm.

[0054] The reaction yield is expressed in mole percent.

[0055] Example 1 Preparation of (R)-7-(2-bromoethyl)-1,4-dioxaspiro[4.5]decane(7) from (S)-2-(1,4-dioxaspiro[4.5]decane-7-yl)ethane-1-ol(6) 1400 g of Ph3P was dissolved in 5500 mL of DCM under a nitrogen atmosphere. The mixture was cooled to 0°C, and 300 mL of Br2 and 2.35 L of pyridine were added dropwise, respectively. The temperature was kept below -10°C during the addition. Next, the reaction mixture was heated to ambient temperature and stirred for 30 minutes. The reaction mixture was cooled to 0°C, and 6,900 g of (S)-2-(1,4-dioxaspiro[4.5]decane-7-yl)ethane-1-ol dissolved in 3.6 L of DCM was slowly added (the temperature was kept below 4°C). The reaction mixture was stirred at ambient temperature for 6 hours. 315 mL of MeOH was added to remove trace amounts of bromine, and the reaction was stirred for 1 hour. The reaction mixture was washed once with water (2300 mL), once with saturated NaHCO3 aqueous solution (2300 mL), and once with 5% Na2S2O3 aqueous solution (1100 mL). The combined aqueous phase was washed twice with DCM (2 × 1350 mL). The combined organic phase was dried over sodium sulfate, and the solvent was evaporated to obtain the crude compound (7). The crude product was mixed with n-hexane (1600 mL), stirred for 3 hours, filtered, and evaporated to obtain (R)-7-(2-bromoethyl)-1,4-dioxaspiro[4.5]decane (7, 1100 g, 91% yield from 6) as a yellow oil.

[0056] 1 H NMR (400MHz, CDCl3) δ3.92(m, 4H), 3.40(t, J=7.0Hz, 2H), 1.79(m, 3H), 1.71(m, 4H), 1.51(m, 1H), 1.41(m, 1H), 1.17(m, 1H), 0.87(m, 1H)ppm 13 C NMR(100MHZ, CDCl3)δ108.9, 64.3, 64.2, 41.0, 39.7, 34.8, 34.2, 31.2, 31.0, 22.9ppm

[0057] Example 2 Preparation of (R)-3-(2-bromoethyl)cyclohexane-1-one (8) from (R)-7-(2-bromoethyl)-1,4-dioxaspiro[4.5]decane (7) (R)-7-(2-bromoethyl)-1,4-dioxaspiro[4.5]decane (7, 1100 g) was dissolved in acetonitrile (17,600 mL) under a nitrogen atmosphere, and 1 M HCl (17,600 mL) was added. The reaction mixture was stirred overnight at ambient temperature. The acetonitrile was then evaporated, and the aqueous phase was extracted four times with MTBE (4 × 4000 mL). The combined organic phase was washed once with saturated NaHCO3 aqueous solution (2000 mL) and once with brine (2000 mL). The organic phase was dried over sodium sulfate. After evaporation of the solvent, crude (R)-3-(2-bromoethyl)cyclohexane-1-one (8, 760 g, 84% yield from 7) was obtained as a pale yellow oil.

[0058] 1 H NMR (400MHz, CDCl3) δ3.41(m, 2H), 2.44(m, 1H), 2.37(m, 1H), 2.26(m, 1H), 2.05(m, 3H), 1.88(m, 3H), 1.69(m, 1H), 1.36(m, 1H)ppm 13 C NMR (100MHz, CDCl3) δ210.8, 47.2, 41.3, 39.1, 37.2, 30.5, 24.9ppm

[0059] Example 3 Preparation of (R)-3-(2-bromoethyl)cyclohexane-1-one (9) from (R)-3-(2-bromoethyl)cyclohexane-1-one (8) Ph3P (146 g), B2(pin)2 (1130 g), CuI (141 g), and MeOLi (211 g) were suspended in DMF (12400 mL) under a nitrogen atmosphere. Subsequently, a solution of crude (R)-3-(2-bromoethyl) cyclohexan-1-one (8,760 g) in DMF (2800 mL) was added. The reaction temperature was slowly raised to 48 °C, and the mixture was stirred for 3 hours. The dark gray solution was filtered through a Celite pad. MTBE (7600 mL) and 1 M HCl (2000 mL) were added to the filtrate, and the aqueous layer was extracted 4 times with MTBE (4 × 7600 mL). The combined organic phases were washed 4 times with brine (4 × 7600 mL) and dried over sodium sulfate. After evaporation of the solvent, crude compound 9 was obtained. After adding n-hexane (15200 mL) to the residue, a precipitate formed. The mixture was stirred for 30 minutes. The resulting precipitate was filtered, and the filtrate was concentrated to obtain crude compound 9. After distillation at about 120 °C under reduced pressure (0.02 mmHg), (R)-3-(2-bromoethyl) cyclohexan-1-one (9,500 g, 53% yield from 8, purity 94% by GC-FID) was obtained as a pale yellow oil.

[0060] 1 H NMR (400 MHz, CDCl3) δ 2.41 (m, 1H), 2.32 (m, 1H) 2.23 (m, 1H), 2.03 (m, 1H), 1.96 (m, 1H), 1.89 (m, 1H), 1.65 (m, 2H), 1.43 (m, 2H), 1.28 (m, 1H), 1.22 (s, 12H), 0.76 (dd, J1 = 9.0 Hz, J2 = 7.6 Hz, 2H) ppm 13 C NMR (100 MHz, CDCl3) δ 212.3, 83.2, 48.1, 41.6, 41.3, 30.9, 30.8, 25.4, 24.9, 8.1 ppm

[0061] Example 4 Preparation of methyl(4R)-2-oxo-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate (10) from (R)-3-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-one (9)

[0062] In a suitable reactor, sodium hydride (190 g, 60% dispersion in mineral oil) was added under an argon atmosphere. Then, cyclohexane (400 mL) was added, and the resulting suspension was stirred at ambient temperature for 20 minutes. Next, the solvent was removed, and a fresh allocation of cyclohexane (400 mL) was added. The procedure was repeated once more. After removing the solvent, dimethyl carbonate (400 mL) was added, and the resulting mixture was stirred at ambient temperature for at least 20 minutes. Dimethyl carbonate was removed, and freshly prepared dimethyl carbonate (3200 mL), DMF (800 mL), and (R)-3-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-one (9, 400 g) were added. The reaction mixture was heated to 75°C for 60 minutes. The mixture was stirred at 75°C for 3 hours. Next, the reaction mixture was cooled to ambient temperature, and saturated NH4Cl aqueous solution (1600 mL) was slowly added over 40 minutes. Then, water (800 mL) was added, and the layers were separated. The aqueous layer was then extracted with MTBE (1600 mL). The combined organic layers were washed with water (4 × 1200 mL). The organic layers were concentrated and then evaporated with 2,2,2-trifluoroethanol (400 mL) to obtain crude (4R)-2-oxo-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate (10, 478 g, yield 97%) as an orange oil.

[0063] 1H NMR (400MHz, CDCl3) δ12.09(s, 1H), 3.74(s, 3H), 2.38~2.29(m, 2H), 2.14~2.07(m, 1H), 2.01~1.88(m, 1H), 1. 82~1.75(m, 1H), 1.60~1.51(m, 1H), 1.45~1.38(m, 2H), 1.24(s, 12H), 1.19~1.07(m, 1H), 0.83~0.73(m, 2H)ppm 13 C NMR (100MHz, CDCl3) δ173.0, 171.9, 97.4, 83.0, 51.3, 35.4, 35.2, 29.9, 28.1, 24.8, 22.0ppm FT-IR(ATR):2978, 2926, 2859, 1746, 1715, 1657, 1618, 1443, 1369, 1321, 1273, 1215, 1144, 1051, 968, 843cm -1

[0064] Example 5 Preparation of methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate (11) from methyl(4R)-2-oxo-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate (10) Crude methyl(4R)-2-oxo-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate (10,478 g) in CF3CH2OH (3770 mL) was added to a suitable reactor under an argon atmosphere. Ammonium acetate (368 g) was then added at ambient temperature. The resulting mixture was stirred at ambient temperature for at least 30 minutes until all NH4OAc was dissolved. The reaction mixture was then cooled to 0°C and t-BuNC (216 ml) was added all at once. The mixture was stirred at 0°C for 48 hours. The reaction mixture was then concentrated under vacuum to approximately 1 / 5 of its initial volume and n-hexane (1 L) was added. The resulting mixture was stirred for 10 minutes and concentrated under vacuum. The resulting mixture was loaded onto a silica gel column (800 g in n-hexane) and filtered. Compound 11 was eluted with DCM / MTBE 1:1 (volume / volume, 10 L), and the fractions containing the product were evaporated together to obtain the crude product (approximately 700 g).

[0065] Crude product 11 was dissolved in i-Pr2O (1200 mL) under an argon atmosphere. The resulting mixture (a clear orange solution) was heated to 50°C and stirred for 60 minutes. The mixture was then slowly cooled to 0°C and stirred overnight at this temperature. The suspension was then cooled to -20°C and stirred for 3 hours. The suspension was then filtered, and the resulting residue was washed with cooled i-Pr2O (400 mL). (1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate (11, 231 g, 9) was obtained as white crystals in a yield of 32%, purity by HPLC.

[0066] 1H NMR (400MHz, CDCl3) δ8.19(s, 1H), 7.63(s, 1H), 3.73(s, 3H), 3.29(d, J=13.2Hz, 1H), 2.25( dd, J1=12.4Hz, J2=4.4Hz, 1H), 2.14~2.06(m, 1H), 2.03~1.92(m, 1H), 1.98(s, 3H), 1.79(br d, J=13.0Hz, 2H), 1.38~1.30(m, 2H), 1.28(s, 9H), 1.22(s, 12H), 1.17~1.06(m, 2H), 0.91~0.68(m, 3H)ppm 13 C NMR (100MHz, CDCl3) δ176.2, 171.2, 170.3, 83.1, 65.8, 52.4, 51.0, 48.5, 40.9, 35.7, 31.2, 30.8, 28.8, 25.3, 25.0, 25.0, 29.4, 8.4ppm FT-IR (ATR): 3354, 3304, 3223, 3055, 2959, 2928, 2870, 1711, 1682, 1659, 1568, 1547, 1481, 1449, 1412, 137 7, 1362, 1317, 1283, 1217, 1175, 1146, 1119, 1103, 1078, 1028, 1009, 966, 949, 924, 893, 870, 843, 822, 712cm -1

[0067] Example 6 Preparation of (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide (5) from methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide (5) - Batch synthesis Methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate (11, 15 g) was dissolved in DCM (150 mL) and cooled to -75°C under an argon atmosphere. Then, a 1 M solution of DIBAL-H in DCM (106 mL) was slowly added over 30 minutes. The mixture was then transferred to another flask containing a cooled mixture of AcOH (9.9 mL), THF (10 mL), and DCM (50 mL) (-75°C). After stirring for 3 minutes, a 2 M solution of dimethylamine in THF (44.2 mL) was added over 5 minutes. The mixture was heated to -20°C and NaBH(OAc)3 (21.55 g) was added to the reaction mixture all at once. The mixture was heated to ambient temperature and stirred for 2 hours. The reaction was quenched with saturated Na2CO3 aqueous solution (200 mL) and stirred at ambient temperature for 30 minutes. Then, H2O (150 mL) was added for extraction and the layers were separated. The aqueous phase was extracted twice with DCM (2 × 100 mL). The combined organic phase was dried over anhydrous Na2SO4, filtered, and evaporated until dry to obtain crude (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide (5, 11.9 g, yield 79%, purity 64% by HPLC) as a colorless oil.

[0068] 1H NMR (400MHz, CDCl3) δ10.21(s, 1H), 8.26(s, 1H), 3.40(dd, J1=13.4Hz, J2=10.4Hz, 1H), 3.18(dt, J1=13.1Hz, J2=2.5 Hz, 1H), 2.23(s, 6H), 2.07(dd, J1=13.1Hz, J2=4.2Hz, 1H), 1.95(dd, J1=13.5Hz, J2=1.6Hz, 1H), 1.88(s, 3H), 1.76(br d, J=12.0Hz, 1H), 1.53~1.44(m, 2H), 1.34~1.31(m, 2H), 1.30(s, 9H), 1.22(s, 12H), 0.99~0.88(m, 2H), 0.84~0.66(m, 3H)ppm 13 C NMR (100MHz, CDCl3) δ172.8, 170.8, 82.9, 65.4, 63.6, 50.4, 45.3, 43.3, 42.2, 35.1, 32.5, 30.8, 28.7, 28.1, 24.8, 24.8, 24.5, 8.3ppm

[0069] Example 7 Preparation of (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide (5) from methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide (5) - In-flow synthesis Sodium triacethoxyborohydride (NaBH(OAc)3, 108 g) and DCM (600 mL) were added to a suitable reactor and cooled to -76°C. The mixed reagents were then supplied to this suspension for 147 minutes (11 / DCM flow: 6.79 mL / min, Me2NH / AcOH / THF flow: 3.86 mL / min, DIBAL-H / DCM flow: 4.81 mL / min, pipe-type reactor, cooling bath temperature: 0°C). During the addition, the temperature inside the batch reactor rose to -62°C. After the addition, the cooling bath was removed and the resulting mixture was stirred at ambient temperature for 2 hours.

[0070] The reaction was quenched with 1000 mL of 20% Na₂CO₃ aqueous solution for 0.5 hours, and the resulting mixture was stirred for 0.5 hours. The resulting suspension was filtered through Celite (only the organic layer was filtered). To recover the product from the aqueous layer, the aqueous phase was extracted with DCM (500 mL). The combined organic layers were evaporated to obtain (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide (5, 97 g, yield 98%, purity 62% by HPLC) as a colorless oil.

[0071] 1 H NMR (400MHz, CDCl3) δ10.21(s, 1H), 8.26(s, 1H), 3.40(dd, J1=13.4Hz, J2=10.4Hz, 1H), 3.18(dt, J1=13.1Hz, J2=2.5 Hz, 1H), 2.23(s, 6H), 2.07(dd, J1=13.1Hz, J2=4.2Hz, 1H), 1.95(dd, J1=13.5Hz, J2=1.6Hz, 1H), 1.88(s, 3H), 1.76(br d, J=12.0Hz, 1H), 1.53~1.44(m, 2H), 1.34~1.31(m, 2H), 1.30(s, 9H), 1.22(s, 12H), 0.99~0.88(m, 2H), 0.84~0.66(m, 3H)ppm 13C NMR (100MHz, CDCl3) δ172.8, 170.8, 82.9, 65.4, 63.6, 50.4, 45.3, 43.3, 42.2, 35.1, 32.5, 30.8, 28.7, 28.1, 24.8, 24.8, 24.5, 8.3ppm

[0072] Example 8 Preparation of (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid (1) from (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide (5) (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide (5) (97 g) was dissolved in MTBE (1000 mL) and cooled to 5°C. The resulting mixture was extracted with pre-cooled (5°C) 0.5 M HCl solution (3 × 150 mL). The combined aqueous fraction was washed with MTBE (330 mL), and the aqueous phase was transferred to a glass-jacketed reactor (2 L), where 12 M HCl (460 mL) was added all at once. The reaction mixture was stirred at 100°C for 2.5 hours. The resulting solution was concentrated under vacuum until dry, and the crude product (63.6 g, 83% yield from 5, 76% purity by UHPLC-FLD) was obtained as a brown oil.

[0073] The crude hydrochloride salt of 1 obtained was dissolved in water (250 mL), and the resulting mixture was loaded onto an ion-exchange resin column prepared from DOWEX® 50WX8 (200-400 mesh, 300 g) and regenerated with 1 M HCl solution and water. The column was eluted with water until the pH was 7. The column was then eluted with 1 M NH3 aqueous solution. The fraction containing 1 (based on TLC, stained with 40% MeOH / CHCl3, KMnO4) was collected. The solvent was evaporated to obtain crude substance 1 (36.3 g, 60% yield from 5, purity 82% by UHPLC-FLD).

[0074] Crude substance 1 was dissolved in water (100 mL) and stirred at 50°C for 1 hour. Acetone (78.6 g) was slowly added over 0.5 hours at 50°C. The resulting mixture was then cooled to 0°C and stirred for 1 hour. The resulting suspension was filtered, and the precipitate was washed with pre-cooled (3°C) acetone (186 mL). After drying, a white solid was obtained (26.1 g, yield 43% from 5, purity 98.9% by UHPLC-FLD).

[0075] Example 9 Recrystallization of (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid (1) Crude material 1 (26.1 g), water (78 mL), and methanol (351 g) were placed in a suitable reactor. The mixture was heated to 65°C and stirred for 0.5 hours. The mixture was concentrated to half its initial volume at 85°C. Then acetone (103 g) was added at 60°C. The mixture was concentrated to half its initial volume at 80°C. Then acetone (103 g) was added over 10 minutes at 50°C. The mixture was concentrated to half its initial volume at 80°C. Then acetone (205 g) was added over 30 minutes at 50°C. The mixture was concentrated to 9 / 10 of its initial volume at 80°C. Then acetone (144 g) was added over 30 minutes at 50°C. Then the mixture was cooled to 0°C and stirred for 1 hour at 0°C. The resulting suspension was filtered, washed with pre-cooled (3°C) acetone (103g), and dried to obtain 1 as a white crystalline substance (23.5g, 39% yield from 5, 99.75% purity by UHPLC-FLD).

[0076] Optical rotation: [α] D 20 = +33.7° (c 1.0, H2O) 1 HNMR (400MHz, D2O) δ2.92(dd, J1=13.1Hz, J2=9.5Hz, 1H), 2.67(dd, J1=13.2Hz, J2=4.8Hz, 1H), 2.51(s, 6H), 2.08~2.03(m, 1H), 1.85~1. 77(m, 2H), 1.70~1.54(m, 3H), 1.31~1.25(m, 2H), 1.07(t, J=12.6Hz,1H), 0.93(dq, J1=13.0Hz, J2=4.5Hz, 1H), 0.75(~t, J=8.2Hz, 2H)ppm 13 C NMR (100MHz, D2O) δ177.6, 63.3, 62.3, 43.7, 43.6, 39.3, 35.1, 30.8, 30.6, 26.4, 11.4ppm FT-IR(ATR):3134, 2992, 2918, 2859, 2826, 2789, 2764, 2727, 1584, 1522, 1458, 14 04, 1369, 1344, 1310, 1263, 1202, 1159, 1105, 1074, 1028, 993, 887, 845, 762, 731cm-1

Claims

1. Formula 11: A method for preparing methyl(1R,2R,4R)-2-acetamido-2-(tert-butylcarbamoyl)-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate, a) Equation 6: (S)-2-(1,4-dioxaspiro[4.5]decane-7-yl)ethane-1-ol was reacted with bromine and triphenylphosphine in the presence of an organic base in the reaction solvent at room temperature, and the reaction mixture was subsequently quenched with water and saturated NaHCO3. ３ Aqueous solution, and Na ２ S ２ O ３ Wash with an aqueous solution, then precipitate triphenylphosphine using a nonpolar solvent, dry, and evaporate the solvent to obtain formula 7: Steps to obtain crude (R)-7-(2-bromoethyl)-1,4-dioxaspiro[4.5]decane, (b) The compound of formula 7 dissolved in the reaction solvent is reacted with an aqueous HCl solution at ambient temperature, the reaction solvent is then removed under vacuum, the aqueous phase is extracted with an organic solvent, and the organic phase is obtained from saturated NaHCO3 ３ Wash with aqueous solution and salt water, evaporate the solvent, and obtain formula 8: Steps to obtain crude (R)-3-(2-bromoethyl)cyclohexane-1-one, c) The compound of formula 8 dissolved in the first solvent is suspended in the second solvent as triphenylphosphine, B ２ (pin) ２ A mixture of CuI and MeOLi is reacted at high temperature, followed by filtration, a third solvent and an aqueous HCl solution are added, the phases are separated, the aqueous phase is extracted with a fourth solvent, the extract is washed with brine, the solvent is evaporated, triphenylphosphine is precipitated using a nonpolar solvent, it is dried, the volatile components are evaporated, and it is distilled under reduced pressure to obtain formula 9: The step of obtaining (R)-3-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-one, d) The compound of formula 9 is reacted with dimethyl carbonate at high temperature in the presence of a strong base in the solvent, followed by saturated NH ４ The reaction was quenched with an aqueous Cl solution, and then extracted with a solvent to obtain equation 10: The step of obtaining methyl(4R)-2-oxo-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate, e) Dissolve the compound of formula 10 in a solvent, add ammonium acetate, cool the solution, and treat with tert-butyl isocyanide to obtain the crude compound of formula 11. f) A step of purifying the crude compound of formula 11 by crystallization from an ether solvent. A method that includes this.

2. The method according to claim 1, wherein in step (a), the organic base is a nitrogen heterocycle, preferably pyridine.

3. The method according to claim 1, wherein in step (a), the reaction solvent is DCM.

4. The method according to claim 1, wherein in step (a), the quenching reagent is an alcohol, preferably methanol.

5. The method according to claim 1, wherein in step (a), the nonpolar solvent is an alkane, preferably n-hexane.

6. The method according to claim 1, wherein in step (b), the reaction solvent is acetonitrile.

7. The method according to claim 1, wherein in step (b), the organic solvent is an ether, preferably MTBE.

8. The method according to claim 1, wherein in step (c), the first solvent and the second solvent are DMF.

9. The method according to claim 1, wherein in step (c), the high temperature is 40°C.

10. The method according to claim 1, wherein in step (c), the third organic solvent and the fourth organic solvent are ether, preferably MTBE.

11. The method according to claim 1, wherein in step (c), the nonpolar solvent is an alkane, preferably n-hexane.

12. The method according to claim 1, wherein in step (d), the strong base is sodium hydride.

13. The method according to claim 1, wherein in step (d), the reaction solvent is DMF.

14. The method according to claim 1, wherein in step (d), the reaction temperature does not exceed 75°C.

15. The method according to claim 1, wherein in step (d), the extraction solvent is MTBE.

16. The method according to claim 1, wherein in step (e), the reaction solvent is 2,2,2-trifluoroethanol.

17. The method according to claim 1, wherein in step (e), the reaction temperature is 0°C.

18. In the step (f), the ether solvent is i-Pr ２ O, the method according to claim 1.

19. Formula 1 for anhydrous form A: A method for preparing the solid crystalline (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid, a) Equation 6: (S)-2-(1,4-dioxaspiro[4.5]decane-7-yl)ethane-1-ol was reacted with bromine and triphenylphosphine in the presence of an organic base in the reaction solvent at room temperature, and the reaction mixture was subsequently quenched with water and saturated NaHCO3. ３ Aqueous solution, and Na ２ S ２ O ３ Wash with an aqueous solution, then precipitate triphenylphosphine using a nonpolar solvent, dry, and evaporate the solvent to obtain formula 7: Steps to obtain crude (R)-7-(2-bromoethyl)-1,4-dioxaspiro[4.5]decane, b) The compound of formula 7 dissolved in the reaction solvent is reacted with an aqueous HCl solution at ambient temperature, the reaction solvent is then removed under vacuum, the aqueous phase is extracted with an organic solvent, and the organic phase is obtained from saturated NaHCO3 ３ Wash with aqueous solution and salt water, evaporate the solvent, and obtain formula 8: Steps to obtain crude (R)-3-(2-bromoethyl)cyclohexane-1-one, c) The compound of formula 8 dissolved in the first solvent is suspended in the second solvent, B ２ (pin) ２ The mixture of CuI and MeOLi is reacted at high temperature, followed by filtration, the third solvent and aqueous HCl solution are added, the phases are separated, the aqueous phase is extracted with the fourth solvent, the extract is washed with brine, the solvent is evaporated, triphenylphosphine is precipitated using a nonpolar solvent, the mixture is dried, the volatile components are evaporated, and the mixture is distilled under reduced pressure to obtain formula 9: The step of obtaining (R)-3-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-one, d) The compound of formula 9 is reacted with dimethyl carbonate at high temperature in the presence of a strong base in the solvent, and the reaction is carried out with saturated NH ４ Quench with an aqueous Cl solution, extract with a solvent, and obtain formula 10: The step of obtaining methyl(4R)-2-oxo-4-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxylate, e) Dissolve the compound of formula 10 in a solvent, add ammonium acetate, cool the solution, and treat with tert-butyl isocyanide to obtain formula 11: Steps to obtain the crude compound, f) A step of purifying the crude compound of formula 11 by crystallization from an ether solvent. g) A step in which the compound of formula 11 is reacted with DIBAL-H in DCM at a low temperature, and the reaction is quenched with an organic acid. h) A step in which the reaction mixture is treated with dimethylamine at a low temperature. i) The reaction mixture is treated with a reducing agent, and the reaction is quenched with a saturated sodium carbonate aqueous solution. j) Extract the reaction mixture with a solvent, and formula 5: Steps to obtain crude (1R,2S,5R)-1-acetamido-N-(tert-butyl)-2-[(dimethylamino)methyl]-5-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethyl)cyclohexane-1-carboxamide, k) Dissolve the crude compound of formula 5 in an ether solvent and extract the mixture into an aqueous HCl solution. 1) The extract is refluxed with a 6 M HCl aqueous solution, cooled, and then evaporated under vacuum. m) The residue is purified using an ion exchange resin column, eluted with an aqueous ammonia solution, and evaporated under vacuum to obtain the crude product of formula 1. n) A step of crystallizing the crude product of formula 1 from a water / acetone system, o) The step of recrystallizing the partially purified product of formula 1 from a (water + methanol) / acetone system, and p) A step in which the crystals are dried to obtain the solid crystalline compound of formula 1 in anhydrous form A. A method that includes this.

20. The method according to claim 19, wherein in step (a), the organic base is a nitrogen heterocycle, preferably pyridine.

21. The method according to claim 19, wherein in step (a), the reaction solvent is DCM.

22. The method according to claim 19, wherein in step (a), the quenching reagent is an alcohol, preferably methanol.

23. The method according to claim 19, wherein in step (a), the nonpolar solvent is an alkane, preferably n-hexane.

24. The method according to claim 19, wherein in step (b), the reaction solvent is acetonitrile.

25. The method according to claim 19, wherein in step (b), the organic solvent is an ether, preferably MTBE.

26. In step (b) above, the weak base is NaHCO ３ The method according to claim 19.

27. The method according to claim 19, wherein in step (c), the first solvent and the second solvent are DMF.

28. The method according to claim 19, wherein in step (c), the high temperature is 40°C.

29. The method according to claim 19, wherein in step (c), the third organic solvent and the fourth organic solvent are ether, preferably MTBE.

30. The method according to claim 19, wherein in step (c), the nonpolar solvent is an alkane, preferably n-hexane.

31. The method according to claim 19, wherein in step (d), the strong base is sodium hydride.

32. The method according to claim 19, wherein in step (d), the reaction solvent is DMF.

33. The method according to claim 19, wherein in step (d), the reaction temperature does not exceed 75°C.

34. The method according to claim 19, wherein in step (d), the extraction solvent is MTBE.

35. The method according to claim 19, wherein in step (e), the reaction solvent is 2,2,2-trifluoroethanol.

36. The method according to claim 19, wherein in step (e), the reaction temperature is 0°C.

37. In step (f) above, the ether solvent is i-Pr ２ The method according to claim 19, wherein the result is O.

38. The method according to claim 19, wherein in step (g), the reaction temperature is -75°C.

39. The method according to claim 19, wherein in step (g), the organic acid is AcOH.

40. The method according to claim 19, wherein in step (h), the reaction temperature is -75°C.

41. The method according to claim 19, wherein in step (i), the reducing agent is sodium triacetoxyborohydride.

42. The method according to claim 19, wherein in step (j), the extraction solvent is DCM.

43. The method according to claim 19, wherein in step (k), the ether solvent is MTBE.

44. The method according to claim 19, wherein in step (m), the ion exchange resin is DOWEX® 50WX8 regenerated with 1 M HCl.

45. In step (m) above, the ammonia aqueous solution is NH ３ The method according to claim 19, wherein the medium is 1M.

46. The method according to claim 19, wherein the order of steps (g), (h), and (i) is replaced by an order comprising: dissolving sodium triacetoxyborohydride in DCM and cooling to -75°C; adding a flow of a mixture of compound 11, dimethylamine in THF, acetic acid, and DIBAL-H in DCM, cooled to 0°C, under flowing conditions; and heating the reaction mixture to ambient temperature.

47. below: (i) XRPD peaks: 7.39, 8.55, 9.49, 12.83, 14.71, 16.86, 17.37, 17.88, 19.11, 19.88, 20.55, 21.19, 22.18, 22.87, 23.66, 24.52, 25.73, 26.09, 26.94, 28.19, 28.61, 28.88, 29.69, 30.28, 31.45, 32.02, 33.06, 33.36, 34.05, 34.52, 35.15, 36.20, 37.52, 38.95, 40.54, 41.76; (ii) IR bands: 3134, 2992, 2918, 2859, 2826, 2789, 2764, 2727, 1584, 1522, 1458, 1404, 1369, 1344, 1310, 1263, 1202, 1159, 1105, 1074, 1028, 993, 887, 845, 762, 731 cm －１ ; (iii) DSC traces showing two broad endothermic events, one starting at 141.9°C and peaking at 173.7°C, and the other starting at 237.4°C and peaking at 254.1°C. A solid crystalline (1R,2S,5R)-1-amino-5-[2-(dihydroxyboranyl)ethyl]-2-[(dimethylamino)methyl]cyclohexane-1-carboxylic acid of formula 1 in anhydrous form A, characterized by at least one of the following:

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