METHOD FOR PRODUCING AN MDM2 INHIBITOR INTERMEDIATE

Description

FIELD OF THE INVENTION

[0001] The present invention provides a process for preparing an intermediate for the preparation of 2-((3R,5R,6S)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-1-((S)-1-(isopropylsulfonyl)-3-methylbutan-2-yl)-3-methyl-2-oxopiperidin-3-yl)acetic acid ("Compound A").BACKGROUND OF THE INVENTION

[0002] p53 is a tumor suppressor and transcription factor that responds to cellular stress by activating the transcription of numerous genes involved in cell cycle arrest, apoptosis, senescence, and DNA repair. Unlike normal cells, which infrequently have a cause for p53 activation, tumor cells are under constant cellular stress from various insults including hypoxia and pro-apoptotic oncogene activation. Thus, there is a strong selective advantage for inactivation of the p53 pathway in tumors, and it has been proposed that eliminating p53 function may be a prerequisite for tumor survival. In support of this notion, three groups of investigators have used mouse models to demonstrate that absence of p53 function is a continuous requirement for the maintenance of established tumors. When the investigators restored p53 function to tumors with inactivated p53, the tumors regressed.

[0003] p53 is inactivated by mutation and / or loss in 50% of solid tumors and 10% of liquid tumors. Other key members of the p53 pathway are also genetically or epigenetically altered in cancer. MDM2, an oncoprotein, inhibits p53 function, and it is activated by gene amplification at incidence rates that are reported to be as high as 10%. MDM2, in turn, is inhibited by another tumor suppressor, p14ARF. It has been suggested that alterations downstream of p53 may be responsible for at least partially inactivating the p53 pathway in p53 WT< tumors. In support of this concept, some p53 WT< tumors appear to exhibit reduced apoptotic capacity, although their capacity to undergo cell cycle arrest remains intact. One cancer treatment strategy involves the use of small molecules that bind MDM2 and neutralize its interaction with p53. MDM2 inhibits p53 activity by three mechanisms: 1) acting as an E3 ubiquitin ligase to promote p53 degradation; 2) binding to and blocking the p53 transcriptional activation domain; and 3) exporting p53 from the nucleus to the cytoplasm. All three of these mechanisms would be blocked by neutralizing the MDM2-p53 interaction. In particular, this therapeutic strategy could be applied to tumors that are p53 WT< , and studies with small molecule MDM2 inhibitors have yielded promising reductions in tumor growth both in vitro and in vivo. Further, in patients with p53-inactivated tumors, stabilization of wildtype p53 in normal tissues by MDM2 inhibition might allow selective protection of normal tissues from mitotic poisons.

[0004] A compound capable of inhibiting the interaction between p53 and MDM2 and activating p53 downstream effector genes would be useful in the treatment of cancers, bacterial infections, viral infections, ulcers and inflammation. In particular, the compound is useful to treat solid tumors such as: breast, colon, lung and prostate tumors; and liquid tumors such as lymphomas and leukemias. As used herein, MDM2 refers to a human MDM2 protein and p53 refers to a human p53 protein. Human MDM2 can also be referred to as HDM2 or hMDM2.

[0005] The compound, 2-((3R,5R,6S)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-1-((S)-1-(isopropylsulfonyl)-3-methylbutan-2-yl)-3-methyl-2-oxopiperidin-3-yl)acetic acid (also referred to herein as Compound A) is a MDM2 inhibitor and has the following chemical structure. Compound A is disclosed in published PCT Application No. WO 2011 / 153509 (Example No. 362) and is being investigated in human clinical trials for the treatment of various cancers. The present invention provides improved a process for preparing an intermediate that is useful in processes for preparing Compound A. US 2018 / 092898 A1 describes processes for making Compound A as well as intermediates and processes for making the intermediates. Also provided are crystalline forms of the compound and the intermediates.SUMMARY OF THE INVENTION

[0006] The present invention provides a process of preparing the following compound (DHO) the process comprising: reacting compound (ABA) with methoxymethylene-N,N-dimethyliminium methyl sulfate. In an embodiment, this reaction is carried out in the presence of a base. In a particular embodiment, the base is an alkali metal salt or an alkaline earth metal salt, such as, for example, KOAc, NaOAc, LiOAc, CaCO 3 and K 2 CO 3 , preferably NaOAc. In an embodiment, the reaction is carried out in a solvent. In a particular embodiment, the solvent is benzene, toluene, o-xylene, m-xylene, p-xylene, hexane, tetrahydrofuran, ethyl acetate, HMPA, HMPT, DMSO, ethylene glycol, DME, DMF, diethyl ether, acetonitrile, methanol, ethanol, acetone or mixtures thereof, preferably the solvent is toluene.

[0007] Also described (not part of the claimed invention) is a crystalline form of (1R,2R,4S)-2-(3-chlorophenyl)-1-(4-chlorophenyl)-4-((S)-4-isopropyl-4,5-dihydrooxazol-2-yl)-4-methylhept-6-en-1-ol (DHO) characterized by a reflection X-ray powder diffraction pattern comprising peaks at 7.3° ± 0.2° 2θ, 14.5° ± 0.2° 2θ, 15.8° ± 0.2° 2θ, 15.9° ± 0.2° 2θ, and 23.1° ± 0.2° 2θ. The reflection X-ray powder diffraction pattern of the DHO crystalline may further comprise peaks at 8.5° ± 0.2° 2θ, 10.0° ± 0.2° 2θ, 11.0° ± 0.2° 2θ, 13.4° ± 0.2° 2θ, 18.8° ± 0.2° 2θ, and 22.0° ± 0.2° 2θ. The reflection X-ray powder diffraction pattern of the DHO crystalline may further comprise one or more peaks at 6.3° ± 0.2° 2θ, 10.5° ± 0.2° 2θ, 11.5° ± 0.2° 2θ, 12.8° ± 0.2° 2θ, 14.8° ± 0.2° 2θ, 15.2° ± 0.2° 2θ, 17.0° ± 0.2° 2θ, 17.5° ± 0.2° 2θ, 17.8° ± 0.2° 2θ, 18.4° ± 0.2° 2θ, 19.0° ± 0.2° 2θ, 19.7° ± 0.2° 2θ, 19.9° ± 0.2° 2θ, 20.7° ± 0.2° 2θ, 21.2° ± 0.2° 2θ, 21.3° ± 0.2° 2θ, 22.4° ± 0.2° 2θ, 23.6° ± 0.2° 2θ, 24.2° ± 0.2° 20, 24.9° ± 0.2° 2θ, 25.7° ± 0.2° 2θ, 26.3° ± 0.2° 2θ, 27.0° ± 0.2° 2θ, 28.3° ± 0.2° 2θ, 28.7° ± 0.2° 2θ, 29.3° ± 0.2° 2θ, 29.7° ± 0.2° 2θ, 30.8° ± 0.2° 2θ, 31.4° ± 0.2° 2Θ, 31.8° ± 0.2° 2θ, 33.0° ± 0.2° 2θ, 34.2° ± 0.2° 2θ, 35.8° ± 0.2° 2θ, 37.0° ± 0.2° 20, and 37.5° ± 0.2° 2θ. The crystalline form of DHO may be a crystalline anhydrate. The reflection x-ray powder diffraction of the crystalline DHO may be carried out using Cu-Kα radiation.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following figures represent specific embodiments of the invention as described and are not intended to otherwise limit the invention. FIG. 1 illustrates the conversion rate of (3S,5R,6R)-3-Allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one (DLAC) to (S)-2-((2R,3R)-2-(3-chlorophenyl)-3-(4-chlorophenyl)-3-hydroxypropyl)-N-((S)-1-hydroxy-3-methylbutan-2-yl)-2-methylpent-4-enamide (ABA ) over time at 60 °C. FIG. 2 illustrates the conversion rate of DLAC to ABA over time at 115 °C. FIG. 3 illustrates the solubility of (1R,2R,4S)-2-(3-chlorophenyl)-1-(4-chlorophenyl)-4-((S)-4-isopropyl-4,5-dihydrooxazol-2-yl)-4-methylhept-6-en-1-ol (DHO) during the crystallization process at 25 °C. FIG. 4 illustrates the solubility of Compound A during the crystallization process. FIG. 5 illustrates a powder X-ray diffraction (PXRD) pattern of crystalline DHO measured in reflection mode. FIG. 6 illustrates a powder X-ray diffraction (PXRD) pattern of crystalline DHO measured in reflection mode with sticks, indicating the peak positions. FIG. 7 illustrates a thermogram from differential scanning calorimetry (DSC) analysis of crystalline DHO. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention provides a process for preparing DHO, which is useful as an intermediate in processes for preparing 2-((3R,5R,6S)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-1-((S)-1-(isopropylsulfonyl)-3-methylbutan-2-yl)-3-methyl-2-oxopiperidin-3-yl)acetic acid ("Compound A"). The invention is defined by the appended claims. Further disclosed subject-matter is only for reference, not part of the invention.

[0010] The present invention employs a bench-stable Vilsmeier reagent, methoxymethylene-N,N-dimethyliminium methyl sulfate (Corbett, M. T.; Caille, S., Synlett 2007, 28, 2845), to achieve the selective in situ activation of a primary alcohol intermediate in the preparation of Compound A.

[0011] Disclosed is also a crystalline form of (1R,2R,4S)-2-(3-chlorophenyl)-1-(4-chlorophenyl)-4-((S)-4-isopropyl-4,5-dihydrooxazol-2-yl)-4-methylhept-6-en-1-ol (DHO) characterized by a reflection X-ray powder diffraction pattern comprising peaks at 7.3° ± 0.2° 2θ, 14.5° ± 0.2° 2θ, 15.8° ± 0.2° 20, 15.9° ± 0.2° 2θ, and 23.1° ± 0.2° 2θ. The reflection X-ray powder diffraction pattern of the DHO crystalline may further comprise peaks at 8.5° ± 0.2° 2θ, 10.0° ± 0.2° 2θ, 11.0° ± 0.2° 2θ, 13.4° ± 0.2° 2θ, 18.8° ± 0.2° 2θ, and 22.0° ± 0.2° 2θ. The reflection X-ray powder diffraction pattern of the DHO crystalline may further comprise one or more peaks at 6.3° ± 0.2° 2θ, 10.5° ± 0.2° 2θ, 11.5° ± 0.2° 2θ, 12.8° ± 0.2° 2θ, 14.8° ± 0.2° 2θ, 15.2° ± 0.2° 2θ, 17.0° ± 0.2° 2θ, 17.5° ± 0.2° 2θ, 17.8° ± 0.2° 2θ, 18.4° ± 0.2° 20, 19.0° ± 0.2° 2θ, 19.7° ± 0.2° 2θ, 19.9° ± 0.2° 2θ, 20.7° ± 0.2° 2θ, 21.2° ± 0.2° 2θ, 21.3° ± 0.2° 2θ, 22.4° ± 0.2° 2θ, 23.6° ± 0.2° 2θ, 24.2° ± 0.2° 2θ, 24.9° ± 0.2° 2θ, 25.7° ± 0.2° 20, 26.3° ± 0.2° 2θ, 27.0° ± 0.2° 2θ, 28.3° ± 0.2° 2θ, 28.7° ± 0.2° 2θ, 29.3° ± 0.2° 2θ, 29.7° ± 0.2° 2θ, 30.8° ± 0.2° 2θ, 31.4° ± 0.2° 2θ, 31.8° ± 0.2° 2θ, 33.0° ± 0.2° 2θ, 34.2° ± 0.2° 2θ, 35.8° ± 0.2° 2θ, 37.0° ± 0.2° 2θ, and 37.5° ± 0.2° 2θ. The crystalline form of DHO may be a crystalline anhydrate. The reflection x-ray powder diffraction of the crystalline DHO may be carried out using Cu-Kα radiation.

[0012] The term "comprising" is intended to be open ended, including the indicated component but not excluding other elements.

[0013] The specific experimental examples presented in this application illustrate specific embodiments of the present invention.

[0014] 1< H-NMR spectra were typically acquired on a Bruker Avance III 500 spectrometer system (Bruker, Billerica, MA) operating at a 1< H frequency of 500.13 MHz, equipped with a Bruker 5 mm PABBI probe with a z-axis gradient; or on a Bruker Avance II or Avance III 400 spectrometer operating at a 1< H frequency of 400.23 MHz, equipped with a Bruker 5 mm PABBO probe with a z-axis gradient. Samples were typically dissolved in 500 µL of either DMSO-d 6 or CD 3 OD for NMR analysis. 1< H chemical shifts are referenced to the residual solvent signals from DMSO-d 6 at δ 2.50 and CD 30 D at δ 3.30.

[0015] Significant peaks are tabulated and typically include the number of protons, multiplicity (s, singlet; d, doublet; dd, doublet of doublets; t, triplet; q, quartet; m, multiplet; br s, broad singlet) and coupling constant(s) in Hertz (Hz). Electron Ionization (EI) mass spectra were typically recorded on an Agilent Technologies 6140 Quadrupole LC / MS mass spectrometer (Agilent Technologies, Englewood, CO). Mass spectrometry results are reported as the ratio of mass over charge, sometimes followed by the relative abundance of each ion (in parentheses). Starting materials in the Examples below are typically either available from commercial sources such as Sigma-Aldrich, St. Louis, MO, or via published literature procedures.

[0016] X-Ray powder diffraction data (XRPD) were obtained using a Bruker D8 Discover X-ray diffraction system (Bruker, Billerica, MA) equipped with a Braun detector and a Cu-Kα radiation source operating in Bragg-Brentano reflection geometry. 2θ values are generally accurate to within an error of ± 0.2°. The samples were generally prepared without any special treatment other than the application of slight pressure to get a flat surface. Samples were measured uncovered unless otherwise noted. Operating conditions included a tube voltage of 40 kV and current of 40 mA. A variable divergence slit was used with a 3° window. The step size was 0.019 °2θ with a step time of 35.2 seconds, and the scanning range is: 3-40.4 °.

[0017] Differential scanning calorimetry (DSC) was carried out with a Perkin Elmer DSC-7 or with a TA Instruments Q2000 instrument. Samples were prepared in a closed gold sample pan at temperature ramp rates of 5°C / minute from 20 °C up to approximately 350 °C. The DSC thermogram of crystalline DHO is shown in FIG. 7 with a melting point at 73.86 °.ExamplesReference Example 1: Method for Preparing Selected Intermediates (not part of the claimed subject matter)

[0018] Step A. 2-(3-Chlorophenyl)-1-(4-chlorophenyl)ethanone

[0019]

[0020] Sodium bis(trimethylsilyl)amide (1 M in tetrahydrofuran, 117 mL) was slowly added to a -78 °C solution of 2-(3-chlorophenyl) acetic acid (10 g, 58.6 mmol) in tetrahydrofuran (58 mL) over 1 hour. After stirring at -78 °C for 40 minutes, a solution of methyl 4-chlorobenzoate (10 g, 58.6 mmol) in tetrahydrofuran (35 mL) was added over a period of 10 minutes. The reaction was stirred at -78 °C for 3 hours and then allowed to warm to 25 °C. After two hours at 25 °C, the reaction was quenched with saturated aqueous ammonium chloride solution, and most of the tetrahydrofuran was removed under reduced pressure. The residue was extracted with ethyl acetate (2 × 100 mL). The combined organic layers were washed with a saturated sodium chloride solution, dried over sodium sulfate, filtered and the filtrate was concentrated. The product was recrystallized from ether / pentane to provide the 2-(3-chlorophenyl)-1-(4-chlorophenyl)ethanone as a white solid.Alternative Procedure for Preparing 2-(3-Chlorophenyl)-1-(4-chlorophenyl)ethanone

[0021] To a mixture of chlorobenzene (170 L, 1684 mol), 3-chlorophenylacetic acid (50 Kg, 293 mol), and dimethylformamide (0.7 L, 9 mol) at 0 °C was added thionyl chloride (39.1 Kg, 329 mol) over the course of 30 min. The mixture was warmed to 15 °C and agitated for 6 h. The mixture was cooled to 0 °C and aluminum chloride (43 Kg, 322 mol) was added over the course of 1.5 h. The mixture was warmed to 20 °C and agitated for 15 h. Water (200 L) and ethanol (200 L) were added to the mixture and the biphasic mixture was agitated for 2 h. The phases were separated and the organic phase was washed twice with aqueous ethylenediaminetetraacetic acid tetrasodium salt (3 wt%, 200 L), and once with water (200 L). Heptane (1600 L) was added to the organic phase over the course of 15 minutes. The suspension was agitated for 30 minutes, cooled to -5 °C, and filtered. The filtered material was dried at 40 °C for 20 h. 2-(3-Chlorophenyl)-1-(4-chlorophenyl)ethanone was isolated in 83.6% yield (67.4 Kg). 1< H NMR (500 MHz, DMSO-d 6 , δ ppm): 8.05 (m, 2H), 7.62 (m, 2H), 7.33 (m, 3H), 7.21 (br d, J = 7.3 Hz, 1H), 4.45 (s, 2H). MS (ESI) = 265.1 [M + H] +< .Step B: Methyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate

[0022]

[0023] Methyl methacrylate (12.65 mL, 119 mmol) was added to a solution of 2-(3-chlorophenyl)-1-(4-chlorophenyl)ethanone (30 g, 113 mmol) (from Step A) in tetrahydrofuran (283 mL). Potassium tert-butoxide (1.27 g, 11.3 mmol) was then added and the reaction was stirred at room temperature for 2 days. The solvent was then removed under vacuum and replaced with 300 mL of ethyl acetate. The organic phase was washed with brine (50 mL), water (3 x 50 mL), and brine (50 mL). The organic phase was dried over magnesium sulfate, filtered and concentrated under vacuum to afford methyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate as an approximately 1:1 mixture of diastereomers. 1< H NMR (400 MHz, CDCl 3 , δ ppm): 7.87 (m, 2H), 7.38 (m, 2H), 7.27-7.14 (series of m, 4H), 4.61 (m, 1H), 3.69 (s, 1.5H), 3.60 (s, 1.5 H), 2.45 (m, 1H), 2.34 (m, 1H), 2.10 (ddd, J = 13.9, 9.4, 5.5 Hz, 0.5H), 1.96 (ddd, J = 13.7, 9.0, 4.3 Hz, 0.5H), 1.22 (d, J = 7.0 Hz, 1.5H), 1.16 (d, J = 7.0, 1.5 H). MS (ESI) = 387.0 [M + 23] +< .Step C: (3S, 5R,6R)-5-(3-Chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one and (3R, 5R,6R)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one

[0024]

[0025] Methyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate (40 g, 104.0 mmol) (from Step B) was dissolved in 200 mL of anhydrous toluene and concentrated under vacuum. The residue was placed under high vacuum for 2 hours before use. The compound was split into 2 x 20 g batches and processed as follows: methyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate (20 g, 52.0 mmol) in anhydrous 2-propanol (104 mL) was treated with potassium tert-butoxide (2.33 g, 20.8 mmol) in a 250 mL glass hydrogenation vessel. RuCl 2 (S-xylbinap)(S-DAIPEN) (0.191 g, 0.156 mmol, Strem Chemicals, Inc., Newburyport, MA) in 3.8 mL of toluene was added. After 1.5 hours, the vessel was pressurized to 50 psi (344.7 kPa) and purged with hydrogen five times and allowed to stir at room temperature. The reaction was recharged with additional hydrogen as needed. After 3 days, the reactions were combined and partitioned between 50% saturated ammonium chloride solution and ethyl acetate. The aqueous layer was extracted with ethyl acetate. The combined organic phases were washed with brine, dried over magnesium sulfate, filtered, and concentrated.

[0026] The crude product (predominantly, (4R,5R)-isopropyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-5-hydroxy-2-methylpentanoate) was dissolved in tetrahydrofuran (450 mL) and methanol (150 mL). Lithium hydroxide (1.4 M, 149 mL, 208 mmol) was added, and the solution was stirred at room temperature for 24 hours. The mixture was concentrated under vacuum and the residue was redissolved in ethyl acetate. Aqueous 1N hydrochloric acid was added with stirring until the aqueous layer had a pH of about 1. The layers were separated and the organic phase was washed with brine, dried over magnesium sulfate, filtered and concentrated. The material was then dissolved in 200 mL of anhydrous toluene and treated with pyridinium p-toluenesulfonate (PPTS, 0.784 g, 3.12 mmol). The reaction was heated to reflux under Dean-Stark conditions until the seco-acid was consumed (about 2 hours). The reaction was cooled to room temperature and washed with saturated sodium bicarbonate (50 mL) and brine (50 mL). The solution was dried over sodium sulfate, filtered and concentrated. The crude material was purified by flash chromatography on silica gel (120 g column; eluting with 100% dichloromethane). The (3S, 5R,6R)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one and (3R, 5R,6R)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one were obtained as a white solid with an approximate 94:6 enantiomeric ratio and a 7:3 mixture of methyl diastereomers. 1< H NMR (400 MHz, CDCl 3 , δ ppm): 7.22-6.98 (series of m, 5H), 6.91 (dt, J = 7.4, 1.2 Hz, 0.3H), 6.81 (m, 2H), 6.73 (dt, J = 7.6, 1.4 Hz, 0.7H), 5.76 (d, J = 4.1 Hz, 0.3 H), 5.69 (d, J = 4.7 Hz, 0.7H), 3.67 (dt, J = 6.6, 4.3 Hz, 0.3H), 3.55 (td, J = 7.8, 4.7 Hz, 0.7 H), 2.96 (d of quintets, J = 13.5, 6.7 Hz, 0.7 H), 2.81 (m, 0.3 H), 2.56 (dt, J = 14.3, 8.0 Hz, 0.7 H), 2.32 (dt, J = 13.69, 7.0 Hz, 0.3 H), 2.06 (ddd, J = 13.7, 8.4, 4.1, 0.3 H), 1.85 (ddd, J = 14.1, 12.5, 7.4, 0.7 H), 1.42 (d, J= 7.0 Hz, 0.9 H), 1.41 (d, J= 6.7 Hz, 2.1H). MS (ESI) = 357.0 [M + 23] +< . [α] D (22 °C, c = 1.0, CH 2 Cl 2 ) = -31.9°; m.p. 98-99 °C.Step D. (3S,5R,6R)-3-Allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one

[0027]

[0028] A solution of (3S, 5R,6R)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one and (3R,5S,6S)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one (4.5 g, 13.4 mmol) (from Step C) and allyl bromide (3.48 mL, 40.3 mmol) in tetrahydrofuran (22 mL) at -35 °C (acetonitrile / dry ice bath) was treated with a solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran (1.0 M, 17.45 mL, 17.45 mmol). The reaction was allowed to warm to -5 °C over 1 hour and then was quenched with 50% saturated ammonium chloride. The reaction was diluted with 100 mL of ethyl acetate and the layers were separated. The organic phase was washed with brine, dried over magnesium sulfate, filtered and concentrated under vacuum to afford the title compound as a white solid upon standing under vacuum. Chiral SFC (92% CO 2 , 8% methanol (20 mM ammonia), 5 mL / min, Phenomenex Lux-2 column (Phenomenex, Torrance, CA), 100 bar (10,000 kPa), 40 °C, 5 minute method) was used to determine that the compound had an enantiomeric ratio of 96:4. (Major enantiomer: title compound, retention time = 2.45 minutes, 96%; minor enantiomer (structure not shown, retention time = 2.12 min, 4%). The (3S,5R,6R)-3-allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one was recrystallized by addition to heptane (4.7 g slurried in 40 mL) at reflux followed by dropwise addition of 1.5 mL of toluene to solubilize. The solution was cooled to 0 °C. The resulting white solid was filtered and rinsed with 20 mL of cold heptane to afford a white powder. Chiral SFC (92% CO 2 , 8% methanol, Phenomenex Lux-2 column, same method as above) indicated an enantiomeric ratio of 99.2:0.8. (major enantiomer, 2.45 min, 99.2%; minor enantiomer: 2.12 min, 0.8%). 1< H NMR (400 MHz, CDCl 3 , δ ppm): 7.24 (ddd, J = 8.0, 2.0, 1.2 Hz, 1H), 7.20-7.15 (series of m, 3H), 6.91 (t, J = 2.0 Hz, 1H), 6.78 (br d, J = 7.6 Hz, 1H), 6.60 (m, 2H), 5.84 (ddt, J = 17.6, 10.2, 7.4 Hz, 1H), 5.70 (d, J = 5.3 Hz, 1H), 5.21-5.13 (series of m, 2H), 3.82 (dt, J = 11.7, 4.5 Hz, 1H), 2.62 (ABX J AB = 13.7 Hz, J AX = 7.6 Hz, 1H), 2.53 (ABX, J AB = 13.9 Hz, J BX = 7.2 Hz, 1H). 1.99 (dd, J = 14.1, 11.9 Hz, 1H), 1.92 (ddd, J = 13.9, 3.9, 1.2 Hz, 1H). 13< C NMR (CDCl 3 , 100 MHz, δ ppm): 175.9, 140.2, 134.5, 134.3, 134.0, 132.2, 129.8, 128.6, 128.0, 127.9, 127.8, 126.4, 119.9, 83.9, 44.5, 42.4, 40.7, 31.8, 26.1. MS (ESI) = 375.2 [M + H] +< . IR = 1730 cm -1< . [α] D (24 °C, c = 1.0, CH 2 Cl 2 ) = -191°. m.p. 111-114 °C.Alternative Procedure for Preparing (3S,5R,6R)-3-allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2- one

[0029] Step 1: Isopropyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate

[0030]

[0031] A solution of 2-(3-chlorophenyl)-1-(4-chlorophenyl)ethanone (Step A) (67.4 Kg, 255 mol) in THF (325 L) was dried azeotropically to achieve a water content by Karl Fisher of 0.05 wt%. Methyl methacrylate (25.8 Kg, 257 mol) was added to the solution and the mixture was heated to 45 °C. A solution of potassium tert-butoxide (20 wt% in THF, 14.3 Kg, 25 mol) was added over the course of 30 minutes and the mixture was agitated for 6 h. The mixture was then cooled to 10 °C and an aqueous solution of citric acid monohydrate (20 wt%, 35 L) was added in less than 5 minutes. Isopropyl acetate (400 L) and an aqueous sodium chloride solution (20 wt%, 300 L) were added. The mixture was agitated for 15 minutes and the phases were separated. The organic phase was distilled under reduced pressure to generate a distillate volume of 560 L while simultaneously adding isopropanol (350 L) to produce a solution of methyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate in isopropanol (54 wt%, 140 kg total solution mass). The solution had a water content of 0.01 wt% by Karl Fisher. Additional isopropanol (420 L) and sulfuric acid (53 Kg, 535 mol) were added to the solution. The mixture was warmed to reflux and agitated for 12 h, during which time 200 L of solvent were distilled and 200 L of fresh isopropanol were added to the mixture. The mixture was then cooled to 20 °C and water (180 L) was added over the course of 30 minutes. Isopropyl acetate (270 L) was added and the mixture was agitated for 30 minutes. The phases were separated and the aqueous phase was extracted using isopropyl acetate (100 L). The combined organic phases were washed with water (200 L) four times. The organic phase was distilled under reduced pressure to generate a distillate volume of 500 L while simultaneously adding isopropanol (50 L) to provide a solution of isopropyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate in isopropanol (60 wt%, 134 kg total solution mass). The solution had a water content of 0.02 wt% by Karl Fisher. The isopropyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate was obtained in 81% overall yield as a roughly 1:1 mixture of diastereoisomers. 1< H NMR (400 MHz, CDCl 3 , δ ppm): 7.70-7.80 (m, 2H), 7.22-7.28 (m, 2H), 7.00-7.18 (series of m, 4H), 4.78-4.96 (m, 1H), 4.42-4.50 (m, 1H), 2.02-2.30 (m, 2H), 1.80-1.95 (m, 1H), 0.99-1.19 (m, 15H).Step 2. (3S,5R,6R)-3-Allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one

[0032]

[0033] To a degassed solution of isopropyl 4-(3-chlorophenyl)-5-(4-chlorophenyl)-2-methyl-5-oxopentanoate (from Step 1) in isopropanol (60 wt%, 252 kg total solution mass, 151 Kg of isopropyl ester starting material, 385 mol) was added degassed isopropanol (900 L) and potassium tert-butoxide (13 Kg, 116 mol). A separately prepared degassed solution of (S)-RUCY ®< -XylBINAP (also known as RuCl[(S)-diapena][(S)-xylbinap] (230 g, 0.2 mol, catalyst, Takasago International Corporation, Rockleigh, NJ) in isopropanol (25 L). The mixture was purged four times with hydrogen at 5 bars (500 kPa) and agitated at 20 °C for 5.5 h. The hydrogen pressurization was discontinued and the mixture was degassed with nitrogen. Tetrahydrofuran (460 L) was added to the mixture. A solution of lithium hydroxide (24 Kg, 576 mol) in water (305 L) was added to the reaction mixture over the course of 40 minutes and the resultant mixture was agitated at 20 °C for 24 h. A solution of concentrated hydrochloric acid (79.3 Kg, 11.4 M, 740 mol) in water (690 L) was added to the mixture over the course of 2 h. Toluene (580 L) was added, the mixture was then agitated for 30 minutes, and the phases were separated. The aqueous phase was extracted using toluene (700 L). The combined organic layers were washed with an aqueous solution of sodium chloride (25 wt%, 700 Kg). The organic phase was distilled at atmospheric pressure and 100 °C to generate a distillate volume of 2700 L while simultaneously adding toluene (800 L). Less than 0.05 wt% isopropanol or water (by Karl Fisher) remained in the mixture after this solvent exchange. Carbonyl diimidazole (59 Kg, 365 mol) was added to the toluene solution over the course of 2 h and the mixture was agitated at 20 °C for two additional hours. The mixture was then cooled to 10 °C and a solution of orthophosphoric acid (72 Kg, 545 mol) in water (400 L) was added over the course of 1 h, while maintaining the temperature of the mixture below 20 °C. The mixture was agitated for 30 minutes, the phases were separated and the organic layer was washed with an aqueous solution of sodium chloride (25 wt%, 484 Kg). Toluene (400 L) was distilled at atmospheric pressure and at 110 °C. After cooling of the solution to 20 °C, tetrahydrofuran (500 L) was added and the water content by Karl Fisher was measured to be 0.03 wt%. The product solution was cooled to -10 °C and a solution allyl bromide (66.8 Kg, 552 mol) in tetrahydrofuran (50 L) was added. A lithium hexamethyldisilazide solution in toluene (255 Kg, 26 wt%, 492 mol) was added over the course of 6 h and the mixture was stirred at -10 °C for 1 h. The mixture was warmed to 0 °C and an aqueous solution of orthophosphoric acid (40 wt%, 400 mol) was added over the course of 3 h. The mixture was warmed to 20 °C. Water (200 L) and dichloromethane (400 L) were added. The mixture was agitated for 15 minutes and the phases were separated. The solution was distilled at atmospheric pressure and 100 °C to generate a distillate volume of 1350 L and the residual toluene in the mixture was measured to be 9.8 wt%. The mixture was cooled to 70 °C. Diisopropyl ether (85 L), water (26 L), and isopropanol (65 L) were added. The mixture was cooled to 35 °C, agitated for 9 h, cooled to 30 °C, and filtered. The filtered material was washed three times with heptane (80 L). The solids were dried at 55 °C for 48 hours to provide 90.1 Kg of (3S,5R,6R)-3-allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one in 63% overall yield. Chiral HPLC indicated an enantiomeric ratio of 99.95:0.05.Reference Example 2: Differences between First-in-human Process and Commercial Process of Making Compound A (not part of the claimed subject matter)

[0034] A gram-scale synthesis of DLAC has previously been reported. See, Sun et al., J. Med. Chem. 2014, 57, 1454. Based on this work, Compound A was prepared by the first-in-human (FIH) synthetic process illustrated in Scheme 1. Intermediate OXOS was used as a regulatory starting material for this process. Ring-opening of DLAC using excess L-valinol (3 equivalents) at elevated temperature afforded amide ABA, which was extracted in dichloromethane. Excess L-valinol was removed using aqueous hydrochloric acid washes and the product solution was carried into the subsequent step without purification. Reduction of the amounts of L-valinol used in this transformation was identified as a development objective going forward in view of the high cost of this raw material. Notably, the preparation of ABA analogues ABA1 or ABA2 from the corresponding DLAC analogues DLAC1 or DLAC2, which bear side-chains containing a group of the same oxidation state as the carboxylic acid of Compound A, was not successful due to the formation of the undesired succinimides SUC1 or SUC2. Considering the similar rates observed for the formation of the desired products ABA1-ABA2 and their transformation to the side-products SUC1-SUC2, it was not possible to isolate the amides ABA1-ABA2 in acceptable yields.

[0035] The oxoiminium salt OXOS was prepared from ABA by double activation with two equivalents of toluenesulfonic anhydride and 2,6-lutidine at elevated temperature. The cation thus prepared was isolated as a 2-naphthylsulfonic acid salt, which offered satisfactory impurity removal properties. Identifying an alternative reagent to toluenesulfonic anhydride (TsO 2 ) was contemplated for multiple reasons, including the need to eliminate the long lasting tosylate intermediate DHO-OTs, which underwent slow transformation to OXOS at elevated temperature (120 °C). This intermediate (DHO-OTs ) is an alkylating agent and thus a potentially mutagenic impurity. One possible option considered was to isolate the crystalline intermediate DHO (Scheme 3) to increase control over the effective removal of impurities for a manufacturing sequence. However, this necessitated the use of a reagent which allowed for the selective chemoselective activation of the primary alcohol of ABA in the presence of the secondary benzylic alcohol. Sulfonic anhydrides reagents did not offer this advantage.

[0036] The preparation of SUL from OXOS was carried out by treatment of the OXOS with isopropylsulfinic acid in the presence of sodium t-butoxide. This transformation proceeds via reversible formation of a diastereomeric pair of sulfinate intermediates (SULFI ) and subsequent rearrangement to the thermodynamic product SUL, which is crystallized from acetonitrile and water (Scheme 4). The ALC side product formed irreversibly under these conditions in the presence of water. Isopropylsulfinic acid, an oil at 20 °C, was prepared from isopropylmagnesium chloride and isolated after an aqueous work-up. Azeotropic drying of this reagent was necessary prior to use in the formation of SUL to avoid generation of the undesired ALC side-product in large quantities. However, isopropyl sulfinate was observed to decompose via disproportionation upon drying and thus this unit operation was avoided. Consequently, the discovery of a stable crystalline salt of isopropylsulfinic acid which was stable under drying conditions and which may be designated as a commercial regulatory starting material was sought. Alternatively, a process for the in situ preparation of a sulfinic acid salt from isopropyl magnesium chloride without an aqueous work-up and further reaction with OXOS was considered.

[0037] Oxidation of the alkene group of SUL was carried out via treatment with catalytic ruthenium chloride (2 mol%) and excess sodium periodate (5 equivalents). The crude product was isolated as a crystalline ethanol solvate. Several features of this step were observed to be undesirable. First, the heavy metal used in this step had to be scavenged, which was accomplished using a DARCO-G resin for the first-in-human delivery. Additionally, multiple equivalents of sodium periodate were necessary to carry out this process and the reagent had to be charged to the reaction vessel in portions to minimize impurity formation. A complex downstream treatment protocol (extractions and filtrations) was required to remove the large amounts of salts utilized for the transformation. Further, multiple dimeric impurities were generated in this transformation step, which made it challenging to control the purity of the drug substance. The use of an ethanol solvate of Compound A as a crystalline control point was problematic and was only moderately effective at removal of the impurities present in the mixture. In addition, the crystallization process had to be conducted as an evaporative process due to the low ethanol concentration (5% v / v) which was necessary to alleviate high mother liquor losses during filtration. The use of ethanol in the crystallization process was also observed to reduce the robustness of the process due to the undesired formation of the corresponding ethyl ester at temperatures above 30 °C and the difficulty experienced in removal of the ethyl ester from the desired ethanol solvate. Similarly, when methanol was used in the crystallization of Compound A, the formation of the corresponding methyl ester at elevated temperatures, which was also difficult to isolate away from the drug substance, significantly reduced the viability of this route for crystallization, especially when operating on multigram scale. Thus, the development of a more consistent and environmentally friendly oxidation process for the preparation of Compound A from SUL as well as the generation of a robust strategy for isolating the drug substance that exhibits the effective control of critical attributes were sought as part of a commercially viable process. Table 1. Modifications to the FIH Process in the Commercial Process to Prepare Compound ACP1 Process Step FIH Process Commercial Process Solution ABA from DLAC Three equivalents of L-Valinol usedReduction of L-Valinol equivalents to twoOXOS from ABA DHO is not isolatedReplacement of Ts 2 O with a chemoselective reagent enabling isolation of DHOOXOS from ABA PMI and long-lasting intermediate DHO-OTs are formedReplacement of Ts 2 O with a reagent enabling the formation of an intermediate undergoing rapid conversion to OXOSSUL from OXOS Isopropylsulfinic acid is a liquid at 20 °C and is unstable to azeotropic drying conditionsDiscovery of a crystalline salt of isopropylsulfinic acid salt that is stable under drying conditionsCompound A from SUL Ruthenium catalyst is used in the last stepChange of reagents for the last stepCompound A from SUL Excess (5 equiv) sodium periodate is used in last stepChange of reagents for the last stepIsolation of Compound A as an ethanol solvate The isolation is only moderately effective at removal of impurities and is not well suited for crystallization designDiscovery of a salt of Compound A well suited to crystallization design and having superior impurity removal propertiesIsolation of Compound A The isolation is poorly effective at removal of the undesired corresponding methyl ester which can form in the crystallization system used (MeOH / H 2 O)Develop a new crystallization of the drug substance, Compound A, which is free from impurity formation Example 3: Development of a Commercial Process to Prepare the Intermediate OXOS

[0038] The thermal amidation of DLAC to ABA with L-valinol proceeded through a multistep mechanism via intermediate ester EST (Scheme 5). The initial transesterification of DLAC to EST was determined to be a reversible process (k 1 > k -1 with 2 equivalents of L-valinol) leading to a build-up of EST prior to rearrangement to the amide product ABA. Upon performing the reaction at 60 °C, rapid conversion of DLAC to EST is observed at the start of the reaction followed by slow conversion of EST to ABA over the course of several days (k 1 > k 2 ) (FIG. 1). At elevated temperatures (115 °C) (FIG. 2), the rearrangement of EST to the more stable ABA is faster, resulting in an increase in the overall rate of the reaction by increasing the concentration of EST.

[0039] The FIH process utilized a thermal melt with 3 equivalents of L-valinol to ensure rapid conversion of DLAC to ABA at 110°C. Consistent with our mechanistic understanding of this transformation, decreasing L-valinol loading (from 3 equivalents to 2 equivalents) resulted in a decrease in the overall rate of the reaction since the conversion of DLAC to EST (k 1 ) directly impacts the relative concentration of EST. When 2 equivalents of L-valinol was used, the reaction was observed to require 72 hours to reach conversion at 115 °C, while employing toluene (1 volume) to ensure reaction homogeneity. This longer processing time, however, may be considered justifiable based on significant cost reductions. Elimination of excess L-valinol was achieved by the addition of toluene (4 volumes) and subsequent washing of the organic mixture with an aqueous hydrochloric acid solution. The resultant organic solution was azeotropically dried and polish filtered to afford ABA in 91% assay yield as a 28 wt% solution in toluene containing 2.7 LC area% of DHO, 1.0 LC area% of starting material DLAC, and 1.0 LC area% of EST. Thermolysis of ABA to prepare directly DHO at higher temperatures led to complex mixtures of products.

[0040] The isolation of intermediate DHO provided an additional opportunity to remove impurities from the process stream and to strengthen the overall control strategy to deliver a drug substance for market application. Paramount to this strategy was the identification of conditions that would untether the dehydrative double-cyclization of ABA to OXOS into two distinct mono-cyclization reactions through the development of a chemoselective activation of the primary alcohol of ABA (conditions A) that would enable the isolation of DHO in crystalline form (Scheme 6).

[0041] Sulfonyl chloride and sulfonic anhydride reagents were found to be unselective in discriminating between the primary and secondary alcohols of ABA and were difficult to procure as anhydrous reagents. Furthermore, the use of acid catalysts also afforded complex mixtures of products. However, a Vilsmeier salt reagent, methoxymethylene-N,N-dimethyliminium methyl sulfate, successfully achieved the desired selectivity. This reagent was easily prepared with no special precautions taken to exclude moisture and it can be stored at 20 °C for several months with no erosion in titer. Additionally, it exhibited milder reactivity and improved chemoselectivity compared to the common halide-derived Vilsmeier salt chloromethylene-N,N-dimethyliminium chloride and also avoided the formation of alkyl halide side-products. The formation of DHO from ABA using methoxymethylene-N,N-dimethyliminium methyl sulfate in toluene was evaluated in the presence of various mild inorganic bases at 25 °C and the conversion to DHO was recorded (Scheme 7). The reaction was observed to perform best with KOAc, but NaOAc was preferred, considering its low hygroscopicity and cost. Base DHO assay yield% Conversion time (hr) KOAc94.62NaOAc91.92LiOAc86.520K 2 CO 3 70.416

[0042] The desired chemoselectivity of this transformation is achieved through the unique ability of methoxymethylene-N,N-dimethyliminium methyl sulfate to undergo dynamic transesterification with alcohols through the generation of labile imidate intermediates. This reversibility was investigated in the activation of 4-chlorobenzyl alcohol (CHA ) with the deuterated reagent DEU to generate imidate IMI, which was found to equilibrate at a 2.5 / 1 ratio of CHA / IMI (Scheme 8). Based on this observation, it is proposed that the IMABA exists in low concentrations during the reaction and undergoes a rapid intramolecular displacement with the pendant amide to generate oxazoline DHO (Scheme 8). Any imidate formed by derivatization of the secondary alcohol group of the ABA group does not undergo further cyclization to OXOS at the operating reaction temperature (30 °C).

[0043] Equilibrium solubility measurements were gathered for DHO in various solvents. It was observed that all values obtained were above 20 mg / mL at 20 °C (including heptane) except for water (<0.1 mg / mL), which was thus selected as an anti-solvent. Acetonitrile was selected as a solvent for crystallization as it resulted in the facile removal of impurities when in combination with water. A curve showing solubility values at different time points in the crystallization process is presented in FIG. 3. Using this protocol, crystalline DHO was isolated in 88% yield from DLAC in a >98 LC area% (Scheme 9).

[0044] A Bruker D8 powder X-ray diffractometer was used to acquire reflection PXRD pattern of the crystalline DHO (FIG. 5) and was equipped with a Braun detector and a Cu-Kα radiation source operating in Bragg-Brentano reflection geometry. The obtained 2-theta (2θ) values were generally accurate to within an error of ± 0.2°. The samples were generally prepared without any special treatment other than the application of slight pressure to achieve a flat surface. Samples were measured uncovered unless otherwise noted. Operating conditions included a tube voltage of 40 kV and current of 40 mA. A variable divergence slit was used with a 3° window. The step size was 0.019 °2θ with a step time of 35.2 seconds. The sample was static during the measurement.

[0045] The peaks listed in Table 2 were identified in the PXRD pattern of crystalline DHO. Table 2. PXRD peaks for crystalline DHO Peak Angle d Value Intensity Rel. Intensity 16.314.1234475314.90%27.312.15811308061.10%38.510.43913252150.00%410.08.8643487117.30%510.58.4251756911.30%611.08.0315693418.50%711.57.67824488.90%812.86.912561812.30%913.46.61879259851.50%1014.56.11557442787.80%1114.85.984834749.40%1215.25.840273316.60%1315.95.573835042100.00%1415.85.59708406080.50%1517.05.2205875715.00%1617.55.057474914.80%1717.84.9750961312.20%1818.44.8239166213.10%1918.84.7216793718.60%2019.04.6774196919.20%2119.74.498051653.30%2219.94.460331693.30%2320.74.287321683.30%2421.24.186053947.80%2521.34.160283997.90%2622.04.0342596319.10%2722.43.9679774114.70%2823.13.84953312161.90%2923.63.7743666513.20%3024.23.6766184016.70%3124.93.566153577.10%3225.73.467674559.00%3326.33.387292625.20%3427.03.300814348.60%3528.33.14692484.90%3628.73.1130562.81.20%3729.33.044351673.30%3829.73.002021182.30%3930.82.90151352.70%4031.42.849143817.50%4131.82.809581132.20%4233.02.714511593.20%4334.22.621561613.20%4435.82.503132014.00%4537.02.4281639.50.80%4637.52.395071122.20%

[0046] Having untethered the double dehydrative cyclization of ABA to OXOS, development of a method to convert DHO to OXOS was needed. Methanesulfonic anhydride (Ms 2 O) was found to provide a faster conversion to OXOS compared to Ts 2 O, as potentially mutagenic mesylate intermediate DHO-OMs is completely consumed at 75 °C in 10 hours. This improvement is likely due to the reduced steric hindrance experienced in the transition state leading from DHO-OMs to OXOS compared to that involved in the cyclization of DHO-OTs to OXOS. The transformation was found to proceed well with 2,6-lutidine as a base in toluene. Nucleophilic organic bases and inorganic bases undesirably afforded complex mixtures of products. The mesylate salt of OXOS generated during the transformation is poorly soluble in toluene and forms a separate liquid layer as the reaction progresses. To enable further processing, it is necessary to dilute the reaction mixture with dichloromethane (8V) prior to removal of the mesylate salts using aqueous sulfuric acid washes. Salt metathesis with aqueous sodium 1-naphthalenesulfonate was followed by distillation of dichloromethane, leading to the crystallization of a 1-naphthalenesulfonate toluene hemi-solvate OXOS salt in 90% yield, 99.5 LC area%, and 99.7 wt% from DHO (Scheme 10).

[0047] The following experimental procedures illustrate the preparation of OXOS.

[0048] N,N-Dimethylformamide dimethyl sulfate adduct: A 500-mL Atlas reactor affixed with a reflux condenser and overhead stirring shaft was charged with dimethyl sulfate (200.0 mL, 2.11 mol, 1.0 equiv.) under a nitrogen atmosphere. The contents of the reactor were warmed to 60 °C. DMF (200.0mL, 2.56 mol, 1.2 equiv.) was added dropwise over 60 minutes (3.3 mL / min). Upon completion of addition, the reaction was stirred for 2 hours at 60 °C. Upon completion of the reaction, the reaction was cooled to room temperature to afford the N,N-dimethylformamide dimethyl sulfate adduct as a solution in residual DMF (402.6 g, 2.02 mol, 95.8% assay yield, 82.8 wt% in DMF).

[0049] (S)-2-((2R,3R)-2-(3-chlorophenyl)-3-(4-chlorophenyl)-3-hydroxypropyl)-N-((S)-1-hydroxy-3-methylbutan-2-yl)-2-methylpent-4-enamide (ABA ): A 5-L ChemGlass reactor affixed with a reflux condenser and overhead stirring shaft was charged with (3S,5R,6R)-3-allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyltetrahydro-2H-pyran-2-one (DLAC ) (201.8 g, 0.53 mol, 98.6 wt%, 1.0 equiv.), L-valinol (110.8 g, 1.06 mol, 2.0 equiv.), and toluene (205 mL, 1 mL / g) under a nitrogen atmosphere. The contents of the reactor were heated under reflux (115 °C) with constant stirring for 72 hours. Upon completion of the reaction, the reaction was cooled to room temperature and diluted with toluene (800 mL, 5 mL / g). The reaction was quenched by portion wise addition of 1N HCl (1000 mL, 5 mL / g). The phases were split and the organic layer was subsequently washed twice with brine (2x400mL, 2 mL / g). The organic phase was dried over magnesium sulfate, filtered through a polish filter (coarse porosity) while rinsing with toluene, and concentrated to a volume of approximately 800mL to afford ABA as a solution in toluene (229.4 g, 0.48 mol, 90.5% assay yield, 27.9 wt% in toluene). 1< H NMR (400 MHz, CHLOROFORM-d) δ ppm: 7.05-7.19 (m, 5H), 6.95 (d, J=8.50 Hz, 2H), 6.84 (d, J=7.67 Hz, 1H), 5.85 (d, J=8.09 Hz, 1H), 5.57 (ddt, J=17.13, 9.98, 7.28, 7.28 Hz, 1H), 4.91-5.03 (m, 2H), 4.71 (d, J=4.77 Hz, 1H), 3.66 (br s, 1H), 3.57-3.63 (m, 1H), 3.51-3.53 (m, 1H), 3.42-3.46 (m, 1H), 3.19 (br s, 1H), 2.97 (dt, J=7.93, 4.95 Hz, 1H), 2.36 (dd, J=13.89, 7.05 Hz, 1H), 2.13 (dd, J=14.62, 4.87 Hz, 1H), 1.96-2.01 (m, 1H), 1.87-1.92 (m, 1H), 1.71-1.82 (m, 1H), 1.10 (s, 3H), 0.88 (d, J=7.05 Hz, 3H), 0.86 (d, J=7.05 Hz, 3H). 13< C NMR (101 MHz, CHLOROFORM-d) δ ppm: 177.47, 142.83, 140.46, 133.79, 133.67, 133.00, 129.49, 129.12, 127.96, 127.93, 127.68, 126.88, 118.64, 75.91, 63.44, 56.94, 49.51, 45.17, 42.13, 39.59, 29.06, 24.07, 19.40, 18.72.

[0050] (1R,2R,4S)-2-(3-chlorophenyl)-1-(4-chlorophenyl)-4-((S)-4-isopropyl-4,5-dihydrooxazol-2-yl)-4-methylhept-6-en-1-ol (DHO ): A 5-L ChemGlass reactor affixed with a reflux condenser and overhead stirring shaft was charged with (S)-2-((2R,3R)-2-(3-chlorophenyl)-3-(4-chlorophenyl)-3-hydroxypropyl)-N-((S)-1-hydroxy-3-methylbutan-2-yl)-2-methylpent-4-enamide (ABA ) (229.4 g, 0.48 mol, 27.9 wt% in toluene, 1.0 equiv.) and toluene (1145 mL, 5 mL / g) under a nitrogen atmosphere. (Note: since ABA is obtained as a stock solution in toluene containing 685 mL of residual toluene, the amount of additional toluene needed is 460 mL). The contents of the reactor were warmed to 30 °C. NaOAc (48.3 g, 0.59 mol, 1.2 equiv.) and N,N-dimethylformamide dimethyl sulfate adduct (174.1 g, 0.72 mol, 82.8 wt%, 1.5 equiv.) were sequentially added to the reaction. After stirring at 30 °C for 2 hours, the reaction was cooled to room temperature. The reaction was quenched with sat. aq. NH 4 Cl (750 mL, 3 mL / g) and H 2 O (500 mL, 2 mL / g). The phases were split and the organic layer was subsequently washed twice with brine (2x750 mL, 3 mL / g). The organic phase was dried over magnesium sulfate, filtered through a polish filter (coarse porosity) while rinsing with toluene, and concentrated in vacuo. The crude residue was recrystallized from MeCN:H 2 O (50:50) to afford DHO as a white crystalline solid (206.5 g, 0.45 mol, 87.7% yield over 2 steps corrected by wt%). 1< H NMR (400 MHz, CHLOROFORM-d) δ ppm: 7.07-7.21 (m, 5H), 6.99 (d, J=8.29 Hz, 2H), 6.88 (d, J=7.10 Hz, 1H), 5.44-5.55 (m, 1H), 4.83-4.97 (m, 2H), 4.73 (d, J=5.60 Hz, 1H), 4.42 (br s, 1H), 4.03 (dd, J=8.91, 7.67 Hz, 1H), 3.63-3.76 (m, 2H), 3.15-3.21 (m, 1H), 2.35 (dd, J=13.89, 7.26 Hz, 1H), 2.13-2.18 (m, 1H), 2.07-2.12 (m, 1H), 1.84 (dd, J=14.72, 8.09 Hz, 1H), 1.48-1.60 (m, 1H), 1.09 (s, 3H), 0.94 (d, J=6.63 Hz, 3H), 0.82 (d, J=6.63 Hz, 3H). 13< C NMR (101 MHz, CHLOROFORM-d) δ ppm: 171.99, 143.48, 140.41, 133.74, 133.35, 132.92, 129.55, 129.09, 128.24, 127.84, 127.75, 126.75, 118.33, 76.63, 71.80, 69.84, 49.36, 42.13, 39.72, 38.61, 32.48, 24.20, 19.10, 18.26.

[0051] (3S,5S,6R,8S)-8-allyl-6-(3-chlorophenyl)-5-(4-chlorophenyl)-3-isopropyl-8-methyl-2,3,5,6,7,8-hexahydrooxazolo[3,2-a]pyridin-4-ium naphthalene-1-sulfonate toluene hemisolvate (OXOS ): A 5-L ChemGlass reactor affixed with a reflux condenser and overhead stirring shaft was charged with (1R,2R,4S)-2-(3-chlorophenyl)-1-(4-chlorophenyl)-4-((S)-4-isopropyl-4,5-dihydrooxazol-2-yl)-4-methylhept-6-en-1-ol (DHO) (199.3 g, 0.40 mol, 93.5 wt%, 1.0 equiv.) and toluene (1000 mL, 5 mL / g) under a nitrogen atmosphere. Methanesulfonic anhydride (88.2 g, 0.49 mol, 1.2 equiv.) and 2,6-lutidine (95.0 mL, 0.82 mol, 2.0 equiv.) were sequentially added to the reaction. The contents of the reactor were heated to 75 °C with constant stirring for 16 hours. Upon completion of the reaction, the reaction was cooled to room temperature and diluted with dichloromethane (1600 mL, 8 mL / g). The reaction was quenched with a solution of conc. H 2 SO 4 (45.0 mL, 0.82 mol, 2.0 equiv.) in H 2 O (955mL, 5 mL / g). The phases were split and the organic layer was subsequently washed twice with an aqueous solution of sodium 1-naphthalenesulfonate (2x72.5 g, 0.31 mol, 0.75 equiv.) in H 2 O (2x800 mL, 4 mL / g). The organic phase was dried over sodium 1-naphthalenesulfonate (10.0 g, 0.04 mol, 0.1 equiv.), filtered through a polish filter (coarse porosity) while rinsing with dichloromethane, and concentrated in vacuo. The crude residue was recrystallized from toluene to afford OXOS as an off-white crystalline solid (260.1 g, 0.37 mol, 90.0% yield corrected by wt%). 1< H NMR (400 MHz, CHLOROFORM-d) δ ppm: 9.14 (d, J=8.50 Hz, 1H), 8.35 (dd, J=7.26, 1.24 Hz, 1H), 7.86 (t, J=8.71 Hz, 2H), 7.57 (t, J=7.70 Hz, 1H), 7.43-7.50 (m, 2H), 7.13-7.39 (m, 7.5H), 7.03-7.10 (m, 3H), 6.07 (d, J=11.20 Hz, 1H), 5.80 (ddt, J=17.00, 9.90, 7.39, 7.39 Hz, 1H), 5.51 (t, J=9.74 Hz, 1H), 5.26-5.34 (m, 2H), 4.76 (ddd, J=10.37, 4.66, 2.18 Hz, 1H), 4.62 (dd, J=9.12, 4.77 Hz, 1H), 3.51-3.60 (m, 1H), 2.86 (t, J=13.68 Hz, 1H), 2.65-2.71 (m, 1H), 2.55-2.60 (m, 1H), 2.35 (s, 1.5H), 1.95 (dd, J=13.89, 3.52 Hz, 1H), 1.52 (s, 3H), 0.54-0.67 (m, 7H). 13< C NMR (101 MHz, CHLOROFORM-d) δ ppm: 183.28, 142.16, 140.01, 137.71, 135.89, 134.15, 134.12, 133.28, 132.15, 130.38, 130.30, 129.95, 129.62, 129.43, 129.06, 128.90, 128.34, 128.09, 127.92, 127.66, 127.41, 127.18, 126.44, 125.88, 125.63, 125.48, 125.16, 124.28, 121.20, 73.14, 67.27, 67.06, 43.64, 43.01, 38.67, 38.56, 26.64, 22.13, 21.32, 18.08, 13.74.

[0052] Alternatively, the intermediate DHO-OMs can be separated and purified before conversion to OXOS.

[0053] 1< H NMR (400 MHz, CHLOROFORM-d) δ ppm: 7.31 (d, J=8.4 Hz, 2H), 7.24-7.18 (m, 2H), 7.16 (s, 1H), 7.08 (d, J=8.2 Hz, 2H), 7.07-7.01 (m, 1H), 5.59 -5.43 (m, 2H), 5.01-4.83 (m, 2H), 3.84 (dd, J=8.1, 9.5 Hz, 1H), 3.55-3.45 (m, 1H), 3.42-3.34 (m, 1H), 3.24-3.13 (m, 1H), 2.46 (s, 3H), 2.39-2.28 (m,1H), 2.28-2.14 (m, 1H), 1.98 (br dd, J=7.8, 13.6 Hz, 1H), 1.72 (dd, J=2.4, 14.3 Hz, 1H), 1.26 (br s, 1H), 1.06 (s, 3H), 0.88 (d, J=6.7 Hz, 3H), 0.71 (d, J=6.7 Hz, 3H). 13< C NMR (101 MHz, CHLOROFORM-d) δ ppm: 169.69, 141.54, 135.61, 134.98, 133.92, 133.43, 129.82, 129.30, 128.81, 128.47, 127.82, 127.34, 118.21, 87.02, 77.22, 69.78, 47.99, 44.57, 39.96, 39.31, 38.46, 32.80, 21.85, 19.40, 18.26.

Claims

1. A process of preparing compound the process comprising: reacting with methoxymethylene-N,N-dimethyliminium methyl sulfate.

2. The process of claim 1, wherein the reaction is carried out in the presence of a base.

3. The process of claim 2, wherein the base is KOAc, NaOAc, LiOAc, or K2CO3.

4. The process of claim 2, wherein the base is NaOAc.

5. The process of any one of claims 1-3, wherein the reaction is carried out in a solvent.

6. The process of claim 5, wherein the solvent is toluene.