Process for preparation of Ibuzatrevir and intermediates

Abstract

The present disclosure relates to a process for the preparation of N-(methoxycarbonyl)-3-methyl-L-valinyl-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl] ethyl}-4-(trifluoromethyl)-L-prolinamide, i.e., I, and forms thereof, and to a process for the preparation of N-(methoxycarbonyl)-3-methyl-L-valinyl-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl] ethyl}- The present invention relates to compounds I, such as their Form 1 polymorphs, their cyclopentylmethyl ether solvates, their isopropyl acetate solvates, their ethyl acetate solvates, and mixtures of their Form 1 polymorphs with microcrystalline cellulose (I), and to compositions comprising solid forms, and to intermediates useful in the preparation of Compound I.

Description

[0001] This invention relates to intermediates and efficient methods for preparing methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, its solvates, and intermediates suitable for preparing those compounds. Methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (hereinafter also referred to as "Compound I") is an antiviral compound with potent inhibitory activity against coronavirus 3CL protease and is an active ingredient under investigation as a potential therapy for treating SARS-CoV-2 (COVID-19) infection. Methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate and its preparation method have been disclosed in PCT International Patent Application WO2021 / 250648, U.S. Patent Application Publication 2022 / 0062232 A1, and U.S. Patent Nos. 11,452,711, 11,351,149, and 11,541,034, as well as U.S. Provisional Patent Application No. 63 / 507,347. The contents of each of the foregoing references are incorporated herein by reference in their entirety. Summary of the Invention

[0002] This invention provides intermediates for the preparation of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobutyr-2-yl}carbamate, its solvates, and synthetic methods, as well as intermediates used in the preparation thereof, the preparation being depicted in reaction formula 1, and the preparation containing several methodological modifications compared to previously disclosed methods. The product of steps 1 and 2 in reaction formula 1 is potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate (compound 6). Compound 6 is a novel intermediate prepared via a highly diastereoselective method, starting with (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester (compound 4) and proceeding via the unseparated intermediate (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester (compound 5). Compound 4 was prepared by the coupling reaction of (2R,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester hydrochloride (1:1) (compound 3) with commercially available (2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyric acid (compound 2). As described below, compound 3 was prepared by reacting commercially available (2R)-4-oxopyrrolidine-1,2-dicarboxylic acid ditert-butyl ester (compound 15) with intermediates 16 to 18 ((2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester, (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester and (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester, respectively). Compound 6 was then coupled with (2S)-2-amino-3-[(3S)-2-oxopyrrolidone-3-yl]propionamide hydrochloride (1:1) (compound 7) to give methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxopyrrolidone-3-yl]prop-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (compound 8). Compound 8 is not typically isolated as a solid; instead, a solution of compound 8 is used in the dehydration step.Compound 8 is dehydrated to form compound 1, which can be isolated as a crystalline solvate, such as ethyl acetate (EtOAc), isopropyl acetate (IPAc), or cyclopentylmethyl ether (CPME) solvate. In reaction formula 1, compound 6 is a potassium salt and compound 7 is a hydrochloride salt. It should be understood that in some embodiments of the invention, alternative salts other than the potassium salt of compound 6 (such as compound 6a, where M) can be used in a similar manner. + for Na + Or Li + The free acid form of compound 6 is (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 6'). Similarly, the free base form of compound 7, (2S)-2-amino-3-[(3S)-2-oxopyrrolidine-3-yl]propionamide (compound 7'), can also be used in a similar manner.

[0003] Reaction 1 After dehydration of compound 8, it is advantageous to separate compound I in the form of a solvate (such as ethyl acetate, isopropyl acetate, or cyclopentyl methyl ether solvate) because this provides a point of impurity removal, allowing for the production of compound I in form 1 with high purity. The solvate of compound I is then converted to a polymorph of compound I in form 1. Compound I in form 1 can then be dissolved and crystallized in the presence of microcrystalline cellulose (MCC) to obtain compound I in form 1 + MCC, where compound I in form 1 exhibits good particle size distribution control. The methyl carbamate molecule {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a tendency to form solvates with most common solvents, and the final form (the polymorph of compound I in form 1) can be obtained by desolvation of the solvate. The resulting solvate of compound I is an unbound solvate, which tends to lose its solvent even at ambient temperatures, posing additional safety risks when handling solids. The solvate step of compound I (converting compound 8 to a solvate of compound I) has been found to be crucial for removing impurities and controlling the particle size of the resulting form 1 of compound I. Due to the challenges in handling and separating the solvate, the method for converting the solvate of compound I to form 1 of compound I is designed without any seeding crystallization, resulting in uncontrollable particle size separation of the final form 1 of compound I. This method produces a wide particle size distribution, posing significant downstream processing challenges for the preparation of suitable pharmaceutical products. Various pathways exist for co-processing active pharmaceutical ingredients and additives. In one approach, the active pharmaceutical ingredient (API) and inactive components can be crystallized and / or precipitated in a solvent-based method, and through a combination of various mechanisms such as API aggregation, hetero-nucleation, surface coating, and dispersion.For methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound I, it has been found that the additive microcrystalline cellulose can be used as a template to induce nucleation at a given concentration, thereby causing methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate to crystallize in the desired polymorphic form (form 1) and the desired particle size distribution. It was also found that microcrystalline cellulose-SiO2 (MCC-SiO2) can be successfully used to provide form 1 of compound I with the desired particle size distribution, while other additives such as calcium diphosphate or silica (SiO2) provide little or no control over the particle size distribution of form 1 of compound I. Additional solid form characterization data for several starting materials and intermediates used in the method are also provided.

[0004] Reaction 2 describes the preparation of compound 6a starting from compound 3.

[0005] Reaction 2 Reaction formula 2 describes the preparation of compound 6a, where M + Monovalent cations, such as K + Na + Or Li + In the presence of a base, compound 3 was coupled to compound 2 under peptide coupling conditions to give compound 4. Compound 4 was then treated with a base to form compound 5 in situ, which subsequently reacted to give compound 6a.

[0006] For the conversion of compounds 4 to 6a, various bases and solvents were explored. Organic amine bases, such as triethylamine, N-methylimidazolium, 1,1,3,3-tetramethylguanidine, triethylenediamine (DABCO), and 1,8-diazabicyclo(5.4.0)undec-7-ene, and the inorganic base potassium carbonate (K₂CO₃), did not induce the formation of compound 6a from compound 4. Lithium tert-butoxide induced epimerization and trace hydrolysis, while sodium tert-butoxide and sodium tert-pentoxide were found to be effective, but the reaction mixture tended to form a gel. Epimerization of tert-leucine at the tert-butyl carbon was observed using potassium hexamethyldisilazide. The reaction proceeded with poor diastereoselectivity using potassium methoxide; and with potassium hydroxide, the reaction was slow and proceeded with poor diastereoselectivity. Advantageously, the reaction proceeded well and with high diastereoselectivity when potassium tert-butoxide or potassium tert-pentoxide were used as bases. The reaction with tert-butoxide or potassium tert-amyloxide is effective in solvents including MTBE, THF, IPA, tert-amyl alcohol, acetonitrile, tert-butanol, and 2-MeTHF. These reaction conditions favor the preparation of the desired product compound 6a (where M... + For K + It can precipitate from the solution and be directly separated. Attached Figure Description

[0007] Figure 1 PXRD pattern of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide, i.e., form 1.

[0008] Figure 2 PXRD pattern of the cyclopentylmethyl ether (CPME) solvate of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide.

[0009] Figure 3 PXRD pattern of isopropyl acetate (IPAc) solvate of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide.

[0010] Figure 4PXRD pattern of the ethyl acetate (EtOAc) solvate of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide.

[0011] Figure 5 PXRD pattern of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide, i.e., form 1.

[0012] Figure 6 Example 3: Particle size and cumulative distribution of batch A (top figure) and batch B (bottom figure).

[0013] Figure 7 Example 3: Particle size and cumulative distribution of batch C (top figure) and images of compound I (form 1) co-treated with microcrystalline cellulose (90 / 10 wt% / wt%).

[0014] Figure 8 Particle size and cumulative distribution of batch D-tray 1 (top figure) and batch E (bottom figure) in Example 3.

[0015] Figure 8A PXRD pattern of compound I in form 1, co-treated with 10 wt% microcrystalline cellulose (MCC).

[0016] Figure 8B Compound I in form 1 was co-treated with 10 wt% MCC. 13 C solid-state NMR spectrum.

[0017] Figure 8C Compound I in form 1 was co-treated with 10 wt% MCC. 19 F solid-state NMR spectrum.

[0018] Figure 8D Particle size distribution of form 1 of compound I from different batches (top: multimodal distribution with D[v,0.5]=5 μm and D[v,0.9]=26 μm) and (bottom: bimodal distribution with D[v,0.5]=3 μm and D[v,0.9]=11 μm, exhibiting extremely fine particles).

[0019] Figure 8E Particle size distribution of a batch of compound I, form 1, D[v,0.5]=76 μm and D[v,0.9]=200 μm (large particles with bimodal distribution).

[0020] Figure 8F Particle size distribution of two batches of compound I form 1 co-treated with 10 wt% MCC: D[v,0.5]=36 μm and D[v,0.9]=98 μm (top figure) and D[v,0.5]=73 μm and D[v,0.9]=165 μm (bottom figure) – both exhibit unimodal distribution.

[0021] Figure 9 Images of compound form 1 co-treated with microcrystalline cellulose (90 / 10 wt% / wt%) (top and bottom).

[0022] Figure 10 PXRD pattern of the free acid of compound 14: (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid.

[0023] Figure 11 PXRD pattern of (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride (1:1), i.e., the HCl salt of compound 14 - Figure 1.

[0024] Figure 12 PXRD pattern of (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride (1:1), i.e., the HCl salt of compound 14 - pattern 2.

[0025] Figure 13 :(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyric acid, i.e., the PXRD pattern of compound 2.

[0026] Figure 14 The PXRD pattern of compound 4 is: (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester.

[0027] Figure 15 PXRD pattern of compound 6' (free acid form): (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid.

[0028] Figure 16 PXRD pattern of compound 6 (potassium salt form): (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid potassium.

[0029] Figure 17PXRD pattern of (2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyric acid, i.e., compound 3 (free form).

[0030] Figure 18 PXRD pattern of (2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyrate salt (1:1), i.e., compound 3 hydrochloride.

[0031] Figure 19 The PXRD pattern of compound 8 is: methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}.

[0032] Figure 20 PXRD pattern of the cocrystal of methyl carbamate tartrate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate tartrate.

[0033] Figure 21 PXRD pattern of the cocrystal of methyl carbamate maleate of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate.

[0034] Figure 22 PXRD pattern of the cocrystal of methyl carbamate succinate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate succinate.

[0035] Figure 23 PXRD pattern of the cocrystal of methyl carbamate fumarate of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate.

[0036] Figure 24PXRD pattern of amorphous methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate. Detailed Implementation

[0037] The invention can be more readily understood by referring to the following detailed description and the embodiments included herein. It should be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. It should be further understood that, unless specifically limited herein, the terminology used herein has its conventional meaning as known in the related art.

[0038] As used herein, unless otherwise specified, the singular forms “a,” “an,” and “the” include plural references. For example, an “an” substituent includes one or more substituents.

[0039] As used herein, the term "about" means within the statistically significant range of values, such as the concentration range, time period, molecular weight, particle size, temperature, or pH. As used herein, "about" means within 20%, preferably 10%, and even more preferably 5% of the indicated value or range. Sometimes, such ranges may be within the typical experimental errors of standard methods used to measure and / or determine a given value or range. The permissible deviation covered by the term "about" depends on the specific system studied and can be readily understood by those skilled in the art. Whenever a range is described in this application, each integer within that range is also considered an embodiment of the invention.

[0040] As used herein, the term "solvent" refers to the crystal form of a substance containing a solvent. Specific solvates of Compound I include ethyl acetate, isopropyl acetate, and cyclopentylmethyl ether solvates of the compound. The term "hydrate" refers to a solvate in which water is the solvent.

[0041] As used herein, the term “adding a seed crystal” means adding a crystal to a crystallization system in order to initiate or enhance nucleation or to act as a matrix for further crystallization.

[0042] As used herein, the term "API" or "active pharmaceutical ingredient" refers to anhydrous methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate in form 1 (form 1 of compound I). Form 1 of compound I is a non-solventized, amorphous form.

[0043] Examples of characterization identifiers for N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide (form 1 of compound I) are provided below using a combination of single or instrumental methods.

[0044] Compound I, form 1, is characterized by the following characteristic peaks or combinations thereof: at 50.8 ppm ± 0.2 ppm 13 C solid-state NMR peak; At 50.8 ppm and 58.3 ppm 13 C solid-state NMR peaks, with each peak representing ±0.2 ppm; At 50.8 ppm and 43.5 ppm 13 C solid-state NMR peaks, with each peak representing ±0.2 ppm; At 50.8 ppm, 58.3 ppm and 43.5 ppm 13 C solid-state NMR peaks, with each peak representing ±0.2 ppm; At 50.8 ppm ± 0.2 ppm 13 C solid-state NMR peak and at -70.7 ppm ± 0.2 ppm 19 F solid-state NMR peak; At 50.8 ppm and 58.3 ppm 13 C solid-state NMR peaks, with each peak at ±0.2 ppm, and at -70.7 ppm ±0.2 ppm. 19 F solid-state NMR peak; At 50.8 ppm and 43.5 ppm 13 C solid-state NMR peaks, with each peak at ±0.2 ppm, and at -70.7 ppm ±0.2 ppm. 19 F solid-state NMR peak; At 50.8 ppm, 58.3 ppm and 43.5 ppm 13 C solid-state NMR peaks, with each peak at ±0.2 ppm, and at -70.7 ppm ±0.2 ppm. 19 F solid-state NMR peak; At 50.8 ppm ± 0.2 ppm 13C solid-state NMR peaks, and one to four powder X-ray diffraction peaks (Cu Kα radiation) selected from the following: peaks at 9.1°, 9.6°, 10.3° and 16.2° 2θ, where each peak is ±0.2°2θ; At 50.8 ppm and 58.3 ppm 13 C solid-state NMR peaks, each at ±0.2 ppm, and one to four powder X-ray diffraction peaks (Cu Kα radiation) selected from the following: peaks at 9.1°, 9.6°, 10.3° and 16.2° 2θ, each at ±0.2° 2θ; At 50.8 ppm and 43.5 ppm 13 C solid-state NMR peaks, each at ±0.2 ppm, and one to four powder X-ray diffraction peaks (Cu Kα radiation) selected from the following: peaks at 9.1°, 9.6°, 10.3° and 16.2° 2θ, each at ±0.2° 2θ; At 50.8 ppm, 58.3 ppm and 43.5 ppm 13 C solid-state NMR peaks, each at ±0.2 ppm, and one to four powder X-ray diffraction peaks (Cu Kα radiation) selected from the following: peaks at 9.1°, 9.6°, 10.3° and 16.2° 2θ, each at ±0.2° 2θ; At 50.8 ppm ± 0.2 ppm 13 C solid-state NMR peak, at -70.7 ppm ± 0.2 ppm 19 F solid-state NMR peaks, and one to four powder X-ray diffraction peaks (Cu Kα radiation) selected from the following: peaks at 9.1°, 9.6°, 10.3° and 16.2°2θ, where each peak is ±0.2°2θ; At 50.8 ppm and 58.3 ppm 13 C solid-state NMR peaks, where each peak is at ±0.2 ppm, -70.7 ppm ±0.2 ppm. 19 F solid-state NMR peaks, and one to four powder X-ray diffraction peaks (Cu Kα radiation) selected from the following: peaks at 9.1°, 9.6°, 10.3° and 16.2°2θ, where each peak is ±0.2°2θ; At 50.8 ppm and 43.5 ppm 13 C solid-state NMR peaks, where each peak is at ±0.2 ppm, -70.7 ppm ±0.2 ppm. 19The solid-state NMR peak, and one to four powder X-ray diffraction peaks (Cu Kα radiation) selected from the following: peaks at 9.1°, 9.6°, 10.3° and 16.2°2θ, each at ±0.2°2θ; and At 50.8 ppm, 58.3 ppm and 43.5 ppm 13 C solid-state NMR peaks, where each peak is at ±0.2 ppm, -70.7 ppm ±0.2 ppm. 19 F solid-state NMR peaks, and one to four powder X-ray diffraction peaks (Cu Kα radiation) selected from the following: peaks at 9.1°, 9.6°, 10.3° and 16.2°2θ, where each peak is ±0.2°2θ.

[0045] In embodiments of the present invention, form 1 of compound I is characterized by any one or a combination of the peaks listed above.

[0046] As used herein, the term "peptide coupling agent" refers to a reagent used to couple a compound such as a carboxylic acid or carboxylic acid ester to an amine to form an amide bond. Peptide coupling agents include (but are not limited to) those described in Dunetz, JR, Magano, J., Weisenburger, GA Org. Process Res. Dev. 2016, 20, 140-177. Representative peptide coupling agents used in the methods of this invention include (but are not limited to) 2-chloro-1-methylpyridinium p-toluenesulfonate, combinations of 2-hydroxypyridine N-oxide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and combinations of 2-hydroxypyridine N-oxide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. Alternatively, a reagent used to convert a carboxylic acid to an acyl chloride (such as methanesulfonyl chloride) can be used as a "peptide coupling agent." The resulting acyl chloride reacts with an amine to form an amide bond.

[0047] As used herein, the term "dehydrating agent" refers to a reagent used to dehydrate a primary amide group to the corresponding nitrile group. Dehydrating agents include (but are not limited to) those described in Ganesan, M., Nagaraaj, P. Org. Chem. Front. 2020, 7 3792-3814 and Talbi, I. et al. ACS Omega 2018, 3, 5078-5082. Representative dehydrating agents used in the methods of this invention include (but are not limited to) trifluoroacetic anhydride, propanephosphonic anhydride, triphenyl phosphite, diethyl chlorophosphate, ethyl dichlorophosphate, phosphorus trichloride, and tris(dimethylamino)phosphine.

[0048] As used in some embodiments herein, the term "containing M" +"Alkali" refers to alkali metal alkoxides, alkali metal hydroxides, or disilazides, where the alkali metal is potassium, sodium, or lithium. A representative example is "containing M..." + The "alkali" compounds include (but are not limited to) sodium tert-butoxide, sodium tert-amyloxide, potassium methoxide, potassium hydroxide, potassium tert-butoxide, potassium tert-amyloxide, and potassium hexamethyldisilamide. When the alkali metal is potassium, the compound is a "K-containing" compound. + "The alkali".

[0049] As used in some embodiments herein, the term "base" includes (but is not limited to) organic amine bases, which include (but are not limited to) N-methylimidazolium, N-methylmorpholine, diethylamine, triethylamine, and 1,8-diazabicyclo(5.4.0)undec-7-ene.

[0050] As used in this article, the term "primary particles" refers to a single API crystal.

[0051] As used herein, the term "agglomerate" refers to tightly bound API crystals that are difficult to disperse into primary particles during processing and particle size analysis.

[0052] In particle size determination, the median is defined as the value at which half of the population exists above and half below a certain point. For particle size distributions, the median is called D

[50] . D

[50] is a dimension in micrometers that divides the distribution into half above and half below this diameter. The expressions Dv50 or D[v,0.5] are sometimes used for the median of volume distributions.

[0053] As used herein, the term D

[90] means that 90% of the total particles are smaller than that size.

[0054] As used herein, the term D

[50] means that 50% of the total particles are smaller than that size.

[0055] As used herein, the term D

[10] means that 10% of the total particles are smaller than that size.

[0056] As used herein, the term D[4,3] refers to the volume-based average particle size (DeBroukeremean). The volume moment mean is relevant to many samples because it reflects the size of the particles that make up the bulk of the sample volume. This mean is most sensitive to the presence of large particles in the size distribution.

[0057] As used in this article, the term Aspect Ratio 50 or AR50 means that 50% of the particles are larger than and 50% of the particles are smaller than a certain volume.

[0058] As used herein, the term bulk density is the ratio of the mass of loose powder per unit volume, typically expressed in g / mL or g / cm³. 3 express.

[0059] As used herein, the term tapped density refers to the ratio of the mass per unit volume of powder after it has been tapped for a period of time, usually expressed in g / mL or g / cm³. 3 express.

[0060] The bulk density and tap density can be determined using methods such as the United States Pharmacopeia. <616> The bulk density of powders is determined by the method described in USP May 1, 2024.

[0061] In some embodiments, form 1 of compound I has a D

[90] value of less than 200 μm, a D

[50] value of less than 80 μm, and a D

[10] value of less than 20 μm. In some such embodiments, form 1 of compound I has a D

[10] value of about 10 μm to about 15 μm. In other such embodiments, form 1 of compound I has a D

[90] value of about 160 μm to about 190 μm. In other such embodiments, form 1 of compound I has a D

[50] value of about 50 μm to about 70 μm. In other embodiments, form 1 of compound I has a D[4,3] value of about 80 μm to about 90 μm. In some such embodiments, form 1 of compound I has a D

[10] value of about 5 μm to about 20 μm and a D

[90] value of about 150 μm to about 200 μm. In other embodiments, compound I form 1 has a D

[10] value of about 5 μm to about 20 μm, a D

[90] value of about 150 μm to about 200 μm, and a D

[50] value of about 40 μm to about 80 μm.

[0062] In another aspect, the present invention provides compound I in form 1, wherein the first-order particle size distribution has at least one of the following: (a) D

[10] values ​​from approximately 5 μm to approximately 25 μm; (b) D

[50] values ​​from approximately 50 μm to approximately 75 μm; (c) D

[90] values ​​from approximately 165 μm to approximately 190 μm; and (d) D[4,3] values ​​from approximately 75 μm to approximately 95 μm.

[0063] For each of the aforementioned implementation values ​​of D

[10] , it can be combined with any value of D

[50] and / or D

[90] that does not contradict it. For each of the aforementioned implementation values ​​of D

[50] , it can be combined with any value of D

[10] and / or D

[90] that does not contradict it. For each of the aforementioned implementation values ​​of D

[90] , it can be combined with any value of D

[10] and / or D

[50] that does not contradict it.

[0064] The following embodiments E1 to E73 are representative embodiments of the present invention and should be interpreted in a non-limiting manner.

[0065] E1 is used to prepare (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid M. + Methods for salts (compound 6a): The method includes the following steps: a) Combine (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester (compound 4), solvent, and water; and b) Containing M + The base is added to the mixture from step a) to generate in situ the intermediate (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester (i.e., compound 5), which is further reacted to give (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid M + Salt (i.e., compound 6a) ; Where M + Selected from Li + Na + and K + .

[0066] E2 is the method according to E1, wherein the M-containing + The base is selected from sodium tert-butoxide, sodium tert-amyloxide, potassium methoxide, potassium hydroxide, potassium tert-butoxide, potassium tert-amyloxide, and potassium hexamethyldisilamide.

[0067] E3 is the method according to E1 or E2, wherein the M-containing + The base is potassium tert-butoxide or potassium tert-pentoxide.

[0068] E4 is the method according to any one of E1 to E3, wherein the method contains M + The base is potassium tert-butoxide.

[0069] E5 is a method according to any one of E1 to E4, wherein the solvent is selected from: methyl tert-butyl ether, tetrahydrofuran, isopropanol, tert-amyl alcohol, acetonitrile, tert-butanol, and 2-methyltetrahydrofuran.

[0070] E6 is the method described in E1, used to prepare potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate (i.e., compound 6). The method includes the following steps: a) Combine (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester (i.e., compound 4), solvent, and water; and b) Containing K + The base is added to the mixture from step a) to produce, in situ, the intermediate (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester, i.e., compound 5, which is further reacted to give potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (i.e., compound 6). .

[0071] E7 is the method according to E6, wherein the K-containing... + The base is selected from: potassium tert-butoxide, potassium tert-pentoxide, potassium methoxide, potassium hydroxide, and potassium hexamethyldisilamide.

[0072] E8 is the method according to E6 or E7, wherein the K-containing... + The base is potassium tert-butoxide.

[0073] E9 is the method according to any one of E6 to E8, wherein the solvent is selected from: methyl tert-butyl ether, tetrahydrofuran, isopropanol, tert-amyl alcohol, acetonitrile, tert-butanol, and 2-methyltetrahydrofuran.

[0074] E10 is the method according to any one of E6 to E9, wherein in step a), 1.0 equivalent of (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester (i.e., compound 4) is combined with 1 to 10 times the volume of solvent and 1.2 equivalent of water, and in step b), 1.2 equivalent of potassium tert-butoxide is added.

[0075] E11 is the method according to any one of E6 to E10, wherein in step a), 1.0 equivalent of (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester (i.e., compound 4) is combined with 2.5 times the volume of solvent methyl tert-butyl ether (MTBE) and 1.2 equivalent of water at ambient temperature, and in step b), 1.2 equivalent of potassium tert-butoxide (20% by weight in THF) is added at ambient temperature.

[0076] E12 is the method according to E11, which further includes step c): stirring the reaction mixture obtained from step b) at ambient temperature for a period of at least 12 hours.

[0077] E13 is the method according to E12, which further includes step d): after step c), adding 0.5 times the volume of methanol under stirring to obtain a slurry of the reaction mixture.

[0078] E14 is the method according to E13, which further includes step e): filtering the reaction mixture slurry obtained from step d) to separate the solid containing potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate (i.e., compound 6).

[0079] E15 is the method according to E14, which further includes step f): washing the solid obtained from step e) containing potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate (i.e., compound 6) with a mixture of MTBE (1.7 times by volume) and methanol (0.3 times by volume).

[0080] E16 is the method according to E15, which further includes step g): drying the solid obtained in step f) containing potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate (i.e., compound 6).

[0081] E17 is the method according to any one of E14 to E16, wherein the separated solid contains greater than or equal to 90% by weight of crystalline (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate potassium (i.e., compound 6).

[0082] E18 is the method according to E17, wherein the separated solid contains less than 10% by weight of potassium (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate.

[0083] E19 is the method according to E17, wherein the separated solid contains greater than or equal to 95% by weight of crystalline (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate potassium (i.e., compound 6).

[0084] E20 is the method according to E19, wherein the separated solid contains less than 5% by weight of potassium (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate.

[0085] E21 is the method according to E19, wherein the separated solid contains greater than or equal to 98% by weight of crystalline (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate potassium (i.e., compound 6).

[0086] E22 is the method according to E19, wherein the separated solid contains less than 2% by weight of potassium (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate.

[0087] E23 is a method for preparing the solvate of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (compound I). ; The method includes the following steps: h) In the presence of a peptide coupling agent, a base, and a solvent, (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (i.e., compound 6') or a pharmaceutically acceptable salt thereof is reacted with (2S)-2-amino-3-[(3S)-2-oxopyrrolidine-3-yl]propionamide (i.e., compound 7') or a pharmaceutically acceptable salt thereof. , We obtain methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (i.e., compound 8); and i) React compound 8 with a dehydrating agent , A solvate of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., the solvate of compound I, was obtained.

[0088] E24 is the method according to E23, wherein in step h), the peptide coupling agent is selected from 2-chloro-1-methylpyridinium p-toluenesulfonate, a combination of 2-hydroxypyridine N-oxide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and a combination of 2-hydroxypyridine N-oxide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and the base is triethylamine, N-methylmorpholine, or N,N-diisopropylethylamine.

[0089] E24' is the method according to E23 or E24, wherein compound 6 is prepared according to any one of E1 to E22.

[0090] E25 is the method according to E23 or E24, wherein in step h), the solvent is methyl ethyl ketone or isopropyl acetate.

[0091] E26 is the method according to E25, wherein in step i), in the presence of a base selected from N-methylimidazolium, N-methylmorpholine, diethylamine, triethylamine and 1,8-diazabicyclo(5.4.0)undec-7-ene, the dehydrating agent is selected from trifluoroacetic anhydride, propanephosphonic anhydride, triphenyl phosphite, diethyl chlorophosphate, ethyl dichlorophosphate, phosphorus trichloride and tris(dimethylamino)phosphine.

[0092] E27 is the method according to E26, wherein in step i), the dehydrating agent is trifluoroacetic anhydride or propanephosphonic anhydride.

[0093] E28 is the method according to any one of E23 to E27, wherein isopropyl acetate is used as a solvent in steps h) and i), and the reaction mixture from step i) is concentrated and heptane is added thereto to give an isopropyl acetate solvate of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., the IPAc solvate of compound I.

[0094] E29 is the method according to any one of E23 to E27, wherein in step h), the solvent is methyl ethyl ketone, the peptide coupling agent is a combination of 2-hydroxypyridine N-oxide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and the base is triethylamine.

[0095] E30 is the method according to E29, wherein after the coupling reaction is completed, the solvent of the reaction mixture from step h) is exchanged for isopropyl acetate by adding isopropyl acetate and distillation, and in step i), the dehydrating agent is trifluoroacetic anhydride and the base is N-methylmorpholine.

[0096] E31 is the method according to E30, wherein the reaction mixture from step i) is quenched with an aqueous solution of ammonium hydroxide, the layers are separated, and the solvent of the isopropyl acetate layer is exchanged for cyclopentylmethyl ether by adding cyclopentylmethyl ether and distillation.

[0097] E32 is the method according to E31, wherein the cyclopentylmethyl ether mixture from step i) is cooled to 10°C and stirred at 10°C for one hour or longer, and the cyclopentylmethyl ether solvate of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., the CPME solvate of compound I, is separated.

[0098] E33 is a method for preparing polymorphic form 1 of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (i.e., compound I), comprising the following steps: [The method involves preparing polymorphic form 1 of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate.] The ethyl acetate solvate, isopropyl acetate solvate, or methoxycyclopentane solvate of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxopyrrolidine-2-yl}carbamoyl (i.e., compound I) was combined with heptane, and the mixture was heated to a temperature range of 50°C to 100°C while stirring the mixture to obtain methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxopyrrolidine-2-yl}carbamoyl (i.e., compound I).

[0099] E33' is the method according to E33, wherein the ethyl acetate solvate, isopropyl acetate solvate, or methoxycyclopentane solvate of the methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate is prepared according to the methods of E23 to E32.

[0100] E34 is the method according to E33, wherein the mixture is stirred at 60°C to 80°C for a period of 6 to 24 hours.

[0101] E35 is the method according to E34, wherein the mixture is stirred at about 70°C for 6 to 12 hours, then cooled to 20°C for 4 hours and held at 20°C for 2 hours, and then the mixture is separated into form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (i.e., compound I).

[0102] E36 is a method for preparing the ethyl acetate solvate of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (Compound I, ethyl acetate solvate). ; The method includes the following steps: h') In the presence of 2-chloro-1-methylpyridinium p-toluenesulfonate and a base, (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate potassium (i.e., compound 6) is reacted with (2S)-2-amino-3-[(3S)-2-oxopyrrolidine-3-yl]propionamide hydrochloride (1:1) (i.e., compound 7). , We obtain methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (i.e., compound 8); and i') React compound 8 with trifluoroacetic anhydride in ethyl acetate in the presence of N-methylimidazole. , An ethyl acetate solvate of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate was obtained, namely the EtOAc solvate of compound I.

[0103] E37 is the method according to E36, wherein step h') is carried out in methyl ethyl ketone and water.

[0104] E38 is the method according to E37, wherein 1.0 equivalent of (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate potassium (i.e., compound 6) is reacted with 1.15 equivalent of (2S)-2-amino-3-[(3S)-2-oxopyrrolidine-3-yl]propionamide hydrochloride (1:1) (i.e., compound 7) in the presence of 1.2 equivalent of 2-chloro-1-methylpyridinium p-toluenesulfonate, and the base is 3.0 equivalent of N-methylmorpholine.

[0105] E39 is the method according to E38, wherein the reaction mixture in step h') is stirred at 20°C for 4 hours.

[0106] E40 is the method according to E39, wherein the crude reaction mixture from step h') is solvent-exchanged with ethyl acetate by vacuum distillation until the water content is less than 0.2% by weight, to obtain a slurry of methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (i.e., compound 8) in ethyl acetate.

[0107] E41 is the method according to E40, wherein in step i'), the slurry of methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (i.e., compound 8) in ethyl acetate is cooled to 0°C, and 5.0 equivalents of N-methylimidazole are added, followed by the addition of 2.5 equivalents of trifluoroacetic anhydride over 30 minutes, and the reaction mixture is then stirred at 0°C for 1 hour.

[0108] E42 is the method according to E41, which further includes step j): quenching the reaction mixture from step i') with an aqueous mixture of citric acid monohydrate and sodium chloride, separating the resulting layer, and back-extracting the aqueous layer with ethyl acetate.

[0109] E43 is the method according to E42, wherein the combined organic ethyl acetate layer is vacuum concentrated to about half of its original volume, heptane is added, and then the ethyl acetate solvate of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate is separated by filtration.

[0110] E44 is the method according to E43, which further includes the step of: combining the ethyl acetate solvate of the methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate with heptane. The mixture was stirred at 60°C to 80°C for 6 to 24 hours to obtain methyl carbamate in the form of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (i.e., compound I).

[0111] E45 is the method according to E44, wherein the mixture is stirred at about 70°C for 6 to 12 hours, then cooled to 20°C for 4 hours and held at 20°C for 2 hours, and then the methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (i.e., compound I) is separated into form 1.

[0112] E46 is a method for preparing methyl carbamate in form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate with a mixture of microcrystalline cellulose (MCC) or microcrystalline cellulose-SiO2 (MCC-SiO2), the method comprising steps (k) to (q): (k) Methyl carbamate in the form of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate was dissolved in ethyl acetate and heptane; (l) Add seed crystals to the solution obtained in step (k) using about 10% to about 50% by weight of microcrystalline cellulose or microcrystalline cellulose-SiO2, wherein the weight% is the weight% of the microcrystalline cellulose or microcrystalline cellulose-SiO2 relative to the total weight of the microcrystalline cellulose or microcrystalline cellulose-SiO2 and form 1 of compound I. (m) Add heptane to the mixture from step (l); (n) Remove the ethyl acetate present in the mixture from step (m) by constant volume distillation and replace it with heptane until the ethyl acetate content is less than 4% by weight of the total solvent composition to obtain a slurry; (o) Stir the slurry from step (n) at 70°C or higher for at least 6 hours, and then cool it to ambient temperature; (p) Separate the obtained methyl carbamate in form 1 from a mixture of microcrystalline cellulose or microcrystalline SiO2; and (q) Dry the product from step (p).

[0113] E46' is the method according to E46, wherein the methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate is prepared according to any one of E33 to E35 or E44 to E45.

[0114] E47 is the method described according to E46, wherein: (k) Methyl carbamate in form 1, {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, was dissolved in ethyl acetate (6 L / kg form 1) and heptane (2 L / kg form 1) at 60 °C. (l) Cool the solution to 45°C and add seed crystals with 10% by weight of microcrystalline cellulose; (m) Heptane is added to the mixture from step (l) over a period of 4 hours, wherein the amount of heptane added is about 7 L heptane / Kg form 1, and the mixture is cooled to 20°C over a period of not less than 3 hours; (n) Remove ethyl acetate from the mixture from step (c) by constant volume distillation (15 L solvent / Kg form 1) and replace it with heptane until the ethyl acetate content is less than 4% by weight of the total solvent composition to obtain a slurry; (o) Stir the slurry from step (n) at 80°C for at least 6 hours, and then cool it to 20°C for 5 hours; (p) Separate a mixture (90 wt% / 10 wt%) of the obtained methyl carbamate in form 1 with microcrystalline cellulose. (q) Dry the solid mixture from step (p) at 80°C for at least 12 hours.

[0115] E48 is the method according to E46 or E47, wherein the solid mixture obtained from step (g) comprises methyl carbamate in the form of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate having a D

[90] value of less than 200 μm, a D

[50] value of less than 80 μm, and a D

[10] value of less than 20 μm.

[0116] E49 is the method according to E48, wherein the form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a D

[90] value of about 160 μm to about 190 μm.

[0117] E50 is the method according to E48 or E49, wherein the form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a D

[50] value of about 50 μm to about 70 μm.

[0118] E51 is the method according to any one of E48 to E50, wherein the form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a particle size distribution D of about 10 μm to about 15 μm

[10] .

[0119] E52 is the method according to any one of E48 to E51, wherein the form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a D[4,3] value of about 80 μm to about 90 μm.

[0120] E53 is the method according to any one of E48 to E52, wherein the methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has an aspect ratio (AR50) of 0.6 to 0.7 and a g / cm³. 3 Up to 0.40 g / cm 3 The bulk density is 0.45 g / cm³. 3 Up to 0.55 g / cm 3 The tap density.

[0121] E54 is a composition comprising form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamoyl ester and microcrystalline cellulose, wherein form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamoyl ester has a D

[90] value of less than 200 μm, a D

[50] value of less than 80 μm, and a D

[50] value of less than 20 μm. The D

[10] value of μm.

[0122] E55 is the composition according to E54, comprising 90% by weight of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate in the form of 1 and 10% by weight of microcrystalline cellulose.

[0123] E56 is the composition according to E54 or E55, wherein the form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a D

[90] value of about 160 μm to about 190 μm.

[0124] E57 is a composition according to any one of E54 to E56, wherein the form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a D

[50] value of about 50 μm to about 70 μm.

[0125] E58 is a composition according to any one of E54 to E57, wherein the form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a D

[10] value of about 10 μm to about 15 μm.

[0126] E59 is a composition according to any one of E54 to E58, wherein the methyl carbamate form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a D[4,3] value of about 80 μm to about 90 μm.

[0127] E60 is a composition according to any one of E54 to E59, wherein the methyl carbamate form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has an aspect ratio (AR50) of 0.6 to 0.7 and a g / cm³. 3 Up to 0.40 g / cm 3 The bulk density is 0.45 g / cm³. 3 Up to 0.55 g / cm 3 The tap density.

[0128] E61 is the compound (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid; or a salt thereof.

[0129] E62 is a compound according to E61, wherein the salt is selected from lithium, sodium, and potassium.

[0130] E63 is the compound described in E62, which is (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid potassium.

[0131] E64 is a composition comprising 90 wt% of form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamoyl ester and 10 wt% of microcrystalline cellulose, wherein form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamoyl ester has a D

[90] value of 95 μm to 240 μm.

[0132] E65 is the composition according to E64, wherein the form 1 of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate has a D

[50] value of 30 μm to 85 μm.

[0133] E66 is the composition according to E64 or E65, wherein the particle size distribution of the methyl carbamate in form 1, {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate is unimodal.

[0134] E67 is a eutectic that comprises methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate and an organic carboxylic acid selected from tartaric acid, maleic acid, succinic acid, fumaric acid, 4-hydroxybenzoic acid, and 2,5-dihydroxybenzoic acid.

[0135] E68 is a eutectic according to E67, wherein the organic carboxylic acid is tartaric acid.

[0136] E69 is a eutectic according to E67, wherein the organic carboxylic acid is maleic acid.

[0137] E70 is a eutectic according to E67, wherein the organic carboxylic acid is succinic acid.

[0138] E71 is a eutectic according to E67, wherein the organic carboxylic acid is fumaric acid.

[0139] E72 is a eutectic according to E67, wherein the organic carboxylic acid is 4-hydroxybenzoic acid.

[0140] E73 is a eutectic according to E67, wherein the organic carboxylic acid is 2,5-dihydroxybenzoic acid.

[0141] Reaction formulas INT-1, INT-2, and INT-3 describe the preparation of intermediates and compounds used in the method of the present invention.

[0142] Reaction formula INT-1 depicts the preparation of intermediates 10 to 14 and compound 6'.

[0143] Reaction formula INT-1 Specifically, reaction INT-1 depicts the preparation of (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 6') starting from (2R)-4-oxopyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (compound 10). In step 1-1, compound 9 is trifluoromethylated with trimethylsilyltrifluoromethane in the presence of tetrabutylammonium fluoride to quantitatively obtain (2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (compound 10). In steps 1-2, compound 10 is subjected to elimination conditions using bis(2-methoxyethyl)aminosulfur trifluoride (BAST) at pH 7 to 8 to give (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (compound 11). In steps 1-3, compound 11 is reduced by hydrogenation using palladium / carbon (Pd / C) as a catalyst to give (2R,4R)-4-(trifluoromethyl)pyrrole-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (compound 12). In steps 1-4, compound 12 is subjected to alkaline-catalyzed hydrolysis to give (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 13) with a diastereomeric ratio of about 75:25. Subsequently, it is resolved by chiral salt formation in steps 1-5 to give (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (1R)-N-phenylmethyl-1-phenylethylamine (1:1), which is then neutralized to give purified compound 13 with a diastereomeric ratio greater than 98:2. In steps 1-6, compound 13 is deprotected under acidic conditions to give (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride (1:1) (compound 14 HCl salt), which is then neutralized by treatment with a base in steps 1-7 to give (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 14) in the form of a free base. In steps 1-8, compound 14 (free base) is then coupled with commercially available (2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyric acid (compound 2) under peptide coupling conditions to give (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 6'). Compound 6' (free acid) can be coupled to compound 7 or 7' in a similar manner to the coupling of compound 6 and compound 7 in reaction formula 1 to give compound 8. Compound 8 can then be dehydrated to give compound I or its solvate, which can be used to prepare compound I form 1 and compound I form 1 with MCC.

[0144] Reaction INT-2 describes the preparation of (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester hydrochloride (1:1) (Compound 3) starting from commercially available (2R)-4-oxopyrrolidine-1,2-dicarboxylic acid ditert-butyl ester (Compound 15). Compound 15 is reacted with trifluoromethyltrimethylsilane to give (2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester (Compound 16), which undergoes an elimination reaction using trifluoromethanesulfonic anhydride / pyridine, or BAST or DAST, to give (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester (Compound 17). Compound 17 was then reduced by hydrogenation in the presence of catalysts such as palladium / carbon (Pd / C) or palladium acetate Pd(OAc)₂ to give di-tert-butyl (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid (compound 18). Compound 18 was then deprotected under acidic conditions to give compound 3. Compound 3 can then be used to prepare compound I, form 1, as described in reaction formula 1 above.

[0145] Reaction formula INT-2 The following are abbreviations that may be used in this instruction manual: ACN is acetonitrile; AcOH is acetic acid; aq. is aqueous solution; BAST is bis(2-methoxyethyl)aminosulfur trifluoride, ℃ is degrees Celsius; cm is centimeters; CPME is cyclopentylmethyl ether or methoxycyclopentane; d is a doublet; dd is a double doublet; ddd is a double doublet; Da is Dalton; DAST is (diethylamino)sulfur trifluoride; DCM is dichloromethane; DMSO is dimethyl sulfoxide; dr is diastereomeric ratio; dt is a double triplet; EDCI hydrochloride is 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride; ESI is electrospray ionization; EtOAc is ethyl acetate; eq. is equivalent; g is gram; h is hour; HCl is hydrochloric acid or hydrochloride; H2O is water; H3PO4 is phosphoric acid; HRMS is high-resolution mass spectrometry; Hz is Hertz; IPA is isopropanol; IPAc is Isopropyl acetate; K is Kelvin; K₂CO₃ is potassium carbonate; kg is kilogram; kHz is kilohertz; KOt-Bu is potassium tert-butoxide; L is liter; m is multiplet; MCC is microcrystalline cellulose; MeCN is acetonitrile; MEK is methyl ethyl ketone; MeOH is methanol; 2-MeTHF is 2-methyltetrahydrofuran; MHz is megahertz; min is minute; mL is milliliter; μm is micrometer; mmol is millimole; mol is mole; MPa is megapascal; MTBE is methyl tert-butyl ether; NaHCO₃ is sodium bicarbonate; NaOH is sodium hydrochloride; NaOMe is sodium methoxide; NMI is N-methylimidazolium; NMM is N-methylmorpholine; NMR is nuclear magnetic resonance; om is overlapping multiplet; Pd / C is palladium / carbon; ppm is parts per million; PXRD is powder X-ray diffraction; q is quartet; s is singlet; Ra Ni represents Raney Nickel; ssNMR represents solid-state nuclear magnetic resonance; t represents a triplet peak; TBAF represents tetrabutylammonium fluoride; TFAA represents trifluoroacetic anhydride; THF represents tetrahydrofuran; TMSCF3 represents trifluoromethyltrimethylsilane; v / v represents volume / volume and wt% represents weight percentage.

[0146] General experimental procedures Powder X-ray diffraction: Powder X-ray diffraction analysis was performed using a Bruker AXS D4 Endeavor diffractometer equipped with a Cu radiation source. The divergence slit was set to 0.6 mm, and a variable slit was used for the secondary optics. Diffracted radiation was detected using a PSD-Lynx Eye detector. The X-ray tube voltage and current were set to 40 kV and 40 mA, respectively. Data were acquired in an θ-2θ goniometer from 3.0° to 40.0° 2θ at Cu wavelength using a step size of 0.020 degrees and a step time of 0.3 seconds. The sample was prepared by placing it in a silicon low-background sample holder and rotating it during acquisition.

[0147] Powder X-ray diffraction analysis was performed using a Bruker AXS D8 Advance diffractometer equipped with a Cu radiation source. The diffracted radiation was detected by a LYNXEYE_EX detector with an electrically driven slit. Both the primary and secondary optical paths were equipped with 2.5mm Solar slits. The X-ray tube voltage and current were set to 40 kV and 40 mA, respectively. Data were acquired in a locked-coupled scan at a Cu K-α (average) wavelength from 3.0 to 40.0 degrees 2θ using an θ-θ goniometer, with increments of 0.02 degrees and a scan rate of 0.5 seconds per step. Samples were prepared by placing them in a silicon low-background sample holder.

[0148] Data was acquired using two instruments with Bruker DIFFRAC Plus software and analyzed using EVA diffract plus software. The PXRD data file was not processed before peak finding. The peak finding algorithm in EVA software was used to initially assign peaks using selected peaks with a threshold of 1. To ensure accuracy, manual adjustments were made; the output of the automatic assignment was visually checked, and peak positions were adjusted to their maximum values. Peaks with a relative intensity ≥3% were generally selected. Typically, unseparated peaks or those consistent with noise were not selected. The typical error associated with peak positions from PXRD, as specified in USP, is at most + / - 0.2°2θ (USP-941).

[0149] 13 C and 19 Solid-state nuclear magnetic resonance (ssNMR) method Solid-state nuclear magnetic resonance (ssNMR): Placed in Bruker-BioSpin Avance III 600 MHz ( 1 Solid-state NMR (ssNMR) analysis was performed on a CPMAS probe in a (H-frequency) NMR spectrometer. The material was encapsulated in a ZrO2 rotor. A magic angle rotation rate of 15 kHz was used. Spectra were acquired at ambient temperature (probe temperature 25 °C).

[0150] The proton decoupled cross-polarized magic angle rotation (CPMAS) experiment was used to collect... 13 Css NMR spectra. A phase-modulated proton decoupling field of 80 kHz–100 kHz was applied during spectrum acquisition. For form 1, the cross-polarization contact time was set to 2 ms and the cycle delay to 3.5 seconds. The number of scans was adjusted to obtain a sufficient signal-to-noise ratio. Crystallized adamantane was used as the external standard. 13 C CPMAS experiment for reference 13 The C chemical shift scale was used to set its high-field resonance to 29.5 ppm.

[0151] Data collected using proton-decoupled magic angle rotation (MAS) experiments.19 F ss NMR spectra. A phase-modulated proton decoupling field of 80 kHz–100 kHz was applied during spectrum acquisition. For Form 1, spectra were acquired with a cyclic delay of 3.5 seconds. The number of scans was adjusted to obtain a sufficient signal-to-noise ratio. External standard trifluoroacetic acid (50% / 50% v / v in H₂O) was used. 19 For reference, refer to the FMAS experiment. 19 The F chemical shift scale was used to set its resonance to -76.54 ppm.

[0152] Automated peak picking was performed using Bruker-BioSpin TopSpin version 3.6 software. Generally, a threshold of 5% relative intensity was used for initial peak selection. The output of the automated peak picking was visually inspected to ensure accuracy, and manual adjustments were made as necessary. Although specific solid-state NMR peaks are reported in this paper, these peaks do indeed have ranges due to variations in instrumentation, sample, and sample preparation. This is standard practice in solid-state NMR, stemming from inherent variations in peak position. Typical variability in the chemical shift x-axis value is approximately ±0.2 ppm for crystalline solids and ±0.5 ppm for amorphous solids. The solid-state NMR peak heights reported in this paper are relative intensities. Solid-state NMR intensities can vary depending on the actual experimental parameter settings and the thermal history of the sample.

[0153] Particle size assessment The particle size of recrystallized materials is evaluated using laser diffraction. Laser diffraction is recognized by standards and guidance bodies, including ISO and ASTM, and is widely used to determine particle size distribution. In the evaluation, the sample is passed through a laser beam, causing the laser light to scatter over a range of angles. A detector placed at a fixed angle measures the intensity of the scattered light at that location. A mathematical model (Mie or Fraunhoffer theory) is then applied to generate the particle size distribution.

[0154] Particle size is analyzed using laser diffraction (or small-angle light scattering) techniques by dispersing dried sample powder with compressed air. Specifically, the particle size distribution is analyzed using the Sympatec HELOS RODOS system equipped with a Vibri dry powder feeder. The powder sample is dispersed at a dispersion pressure of 0.5 bar. In some cases, an Aspiros microfeeder is used, and the powder sample is dispersed at a dispersion pressure of 0.2 bar. A suitable lens is selected to cover the particle size range of each sample.

[0155] The particle surface area can be determined by methods known in the art, such as the gas adsorption method (BET) originally described by S. Brunauer, PHEmmet, E. Teller, Adsorption of gases in multimolecular layers, J. Am. Chem. Soc., 60 (1938), pp. 309-319.

[0156] Preparation of intermediates Preparation of (2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (Compound 10) (Step 1-1) (2R)-4-oxopyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester, i.e., compound 9, was loaded into a reaction vessel, followed by the addition of tetrahydrofuran (THF, 7 L / kg compound 9), and then trimethylsilyltrifluoromethane (TMSCF 31.2 equivalents). The temperature was adjusted to -15°C to -10°C. Tetrabutylammonium fluoride (TBAF 1350 mL, 0.14 equivalents) was added to the reaction vessel, and the temperature was adjusted to -5°C to -10°C. The resulting mixture was stirred at -5°C to -10°C for 16 hours. A 10% aqueous solution of ammonium chloride (NH4Cl, 0.5 L / kg compound 9) was added to the reaction vessel, and then concentrated at 40°C / -0.085 MPa to remove THF. MTBE (4 L / kg compound 9) was added, followed by 2% aqueous citric acid (4 L / kg compound 9) to the reaction vessel, and the mixture was stirred at 20°C to 30°C for 10 minutes. The organic phase was separated and collected, and washed with water (0.4 L / kg compound 9). The organic phase was concentrated to dryness and exchanged with THF until the water content, as measured by KF, was <0.5% by weight. (2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester, compound 10, was obtained and used directly in the next step. 1 H NMR (400 MHz, DMSO- d 6 , 298K): δ 6.57 (s, 1H), 4.50-4.43 (m, 1H), 3.69-3.65 (m, 3H), 3.61-3.57 (m, 1H), 3.53-3.50 (m, 1H), 2.64-2.49 (m, 1H),2.14-2.09 (m, 1H), 1.45-1.30 (m, 9H). 19 F NMR (376 MHz, DMSO-d 6 , 298K): δ -79.88. 13 C NMR (101 MHz, DMSO- d 6 (298K): δ 172.5-171.6 (m), 153.9-153.2 (m), 130.0-121.4 (m), 80.3-79.9 (m), 78.8-76.9 (m), 58.1-57.8 (m), 53.6-53.3 (m), 52.6-52.3 (m), 37.4-36.6 (m), 28.3-28.2 (m, 3C). References: Angew. Chem. Int. Ed 2002, 41 , 1600-1602.

[0157] Preparation of (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (compound 11) (steps 1-2) (2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester, i.e., compound 10, was loaded into a suitable reaction vessel, followed by the addition of dichloromethane (DCM 5 L / kg compound 10). The temperature was adjusted to -30°C to -20°C, and then bis(2-methoxyethyl)aminosulfur trifluoride (BAST, 1.4 equivalents) was slowly added to the reaction vessel over a period of 0.5 to 3 hours at -30°C to -20°C. The temperature was adjusted to 20°C to 30°C, and the reaction mixture was stirred at 20°C to 30°C for 12 hours. The temperature was then adjusted to 0°C to 10°C, and a 7% aqueous solution of sodium bicarbonate (NaHCO3, 16 L / kg compound 10) was added to the reaction mixture to adjust the pH to 7 to 8. The reaction mixture was stirred at 20°C to 30°C for 0.5 hours. The layers were separated, and the organic layer was concentrated to remove the DCM. MTBE (5 L / kg compound 10) was added to the reaction vessel, followed by water (2 L / kg compound 10). The layers were separated, and the organic layer was washed with water (2 L / kg compound 10). The organic layer was concentrated to dryness. The crude product was filtered through a 5 kg silica gel pad, and the resulting solution was concentrated to dryness. 3000 g of an oily substance (R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid 1-(tert-butyl) ester 2-methyl ester, namely compound 11 (2-step separation yield: 60%), was obtained. 1 H NMR (400 MHz, DMSO- d6 , 298K): δ 6.72-6.68 (m, 1H), 5.19-5.15 (m, 1H), 4.34-4.30 (m, 2H), 3.72-3.69 (m, 3H), 1.42-1.36 (m, 9H). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -64.0. 13 C NMR (101 MHz, DMSO- d 6 (298K): δ 169.5-169.1 (m), 153.1-152.6 (m), 131.3-130.0 (m, 2C), 125.5-117.3 (m), 801.6-80.5 (m), 66.9-66.7 (m), 53.0-52.9 (m), 51.0-50.9 (m), 28.3-28.1 (m, 3C). References: Angew. Chem. Int. Ed 2002, 41 , 1600-1602.

[0158] Preparation of (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (compound 12) (steps 1-3) (R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid 1-(tert-butyl) ester 2-methyl ester, i.e., compound 11 (700.00 g), was loaded into a reaction vessel, followed by the addition of methanol (MeOH 10 L / kg compound 11). Palladium / carbon (Pd / C (5 wt%, 0.3 wt% based on compound 11)) was added to the reaction vessel, followed by the addition of acetic acid (AcOH 0.5 equivalent). The reaction vessel was purged three times with argon at 0.4 MPa, followed by three times with hydrogen (H2) at 0.4 MPa. The pressure of the reaction vessel was adjusted to 45 psi under H2 flow. The reaction mixture was stirred at 25°C to 35°C for 16 hours. A sample was obtained for reaction completion analysis. The suspension was filtered and the methanol solution was transferred. The mixture was concentrated at 40°C - 0.085 MPa until no fraction was observed. An oily substance was obtained and loaded into a second reaction vessel. MTBE (2 L / kg) was added to the second reaction vessel. The resulting mixture was washed with saturated NaHCO3 solution (3 L / kg), followed by washing with water (2 L / kg). The organic phase was then concentrated at 40 °C / -0.085 MPa until no fraction was observed. (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid 1-(tert-butyl) ester 2-methyl ester, compound 12 (90% separation yield), was obtained.

[0159] 1 H NMR (400 MHz, DMSO- d 6 , 298K): δ 4.37-4.30 (m, 1H), 3.82-3.71 (m,1H), 3.68-3.62 (m, 3H), 3.43-3.21 (m, 2H), 2.65-2.56 (m, 1H), 1.95-1.79 (m,1H), 1.43-1.26 (m, 9H). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -69.5. 13 C NMR (101MHz, DMSO- d 6 , 298K): δ 172.7-172.2 (m), 153.5-153.0 (m), 131.1-122.8 (m), 80.2-80.1 (m), 58.7-58.4 (m), 52.5-52.4 (m), 41.3-40.7 (m), 30.0-29.1 (m),28.4-28.2 (m, 3C). Preparation of (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 13) (where dr is approximately 75:25) (steps 1-4) 100 g of (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester, i.e., compound 12, was loaded into a reaction vessel, followed by the addition of tetrahydrofuran (THF 10 L / kg compound 12) and the temperature was adjusted to 25°C to 30°C. Sodium methoxide (NaOMe (30% in MeOH), 2.0 equivalent) was added to the reaction vessel at 25°C to 30°C. The reaction mixture was stirred at 25°C to 30°C for 2 hours, followed by the addition of water (5 L / kg compound 12) and stirring at 25°C to 30°C for 2 hours. The reaction mixture was then neutralized to pH 7 to 8 with HCl (3 M) at 5°C to 10°C. The MeOH was removed under vacuum, and the resulting mixture was extracted with ethyl acetate (twice, 1 L EtOAc / kg compound 12). The aqueous layer was acidified to pH 3 to 4 with HCl (1 M) and extracted with EtOAc (3 times, 1 L EtOAc / kg compound 12). The combined organic layers were concentrated to give (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid, i.e., compound 13, a mixture of other diastereomers (separation yield: 83%; typical dr approx. 75:25).

[0160] Resolution of (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 13) (dr approx. 75:25 to dr > 98:2) (steps 1-5 - chiral resolution steps) Procedure: (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid, i.e., compound 13 (dr approximately 75:25 mixture), and acetonitrile MeCN (17 L / kg compound 13) were added to the reaction vessel, and the temperature was adjusted to 25°C to 30°C. A solution of (1R)-N-benzylmethyl-1-phenyl-ethylamine (1.3 equivalents, based on pure compound 13) in MeCN (3 L / kg (1R)-N-benzylmethyl-1-phenyl-ethylamine) was added over a 5-hour period at 25°C to 30°C. The resulting mixture was stirred at 25°C to 30°C for 16 hours. The mixture was filtered, and the wet filter cake was washed with MeCN (2 L / kg compound 13). The filter cake was dried under vacuum at 35°C to 45°C. (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (1R)-N-benzyl-1-phenyl-ethylamine salt was obtained (separation yield: 76%; typical chiral purity: >99.9%). This salt and water (3 L / kg salt) were added to a reaction vessel, and the temperature was adjusted to 25°C to 30°C. An aqueous solution of sodium hydroxide (2 equivalents of NaOH in 1 L H₂O / kg salt) was added at 25°C to 30°C. The resulting reaction mixture was stirred at 25°C to 30°C for 2 hours. MTBE (5 L / kg) was added to the reaction vessel, and the mixture was stirred for 0.5 hours, followed by separation of the layers. The aqueous layer was extracted twice with MTBE (3 L / kg). The temperature was adjusted to 0°C to 10°C, and the pH of the mixture was adjusted to 3 to 4 with 1 M H₃PO₄ at 0°C to 10°C. The mixture was stirred at 0°C to 10°C for 3 hours. The filter cake was filtered and washed with water (1 L / kg). The filter cake was dried under vacuum at 35°C to 45°C. (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 13) was obtained (separation yield: 85%).

[0161] Product characterization of (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid: The sample contained a minor rotational isomer, accounting for approximately 40% of the sample.

[0162] 1 H NMR (600 MHz, DMSO- d 6 , 298K): δ 12.81 (s, 1H), 4.26 (dd, J = 9.28, 3.10 Hz (minor), 4.22 (dd, J = 9.09, 3.63 Hz, 1H), 3.62 (m, 1H), 3.42 (d, J= 11.26Hz, 1H), 3.26 (m, 1H), 2.42-2.37 (m, 1H) 2.39-2.32 (m, minor), 2.21-2.15 (m, 1H), 2.19-2.13 (m, minor) 1.40 (s, minor), 1.35 (s, 9H). 19 F NMR (376 MHz, DMSO- d 6 ,298K): δ -70.2. 13 C NMR (151 MHz, DMSO- d 6 , 298K): δ 173.3, 172.9 (minor), 153.0 (minor), 152.8, 127.0 (1 JCF= 277.5 Hz), 126.9 (1 JCF= 277.5 Hz (minor), 79.5 (minor) 79.4, 58.1, 57.9 (minor), 45.3 (minor), 45.2, 40.3 (2 JCF= 27.2 Hz (minor), 39.7 (2 JCF= 27.2 Hz), # 29.2, 28.4 (minor), 27.9 (minor), 27.8. #=Due to solvent overlap, the coupling constant could not be accurately determined. It was calculated as an equivalent to the minor rotational isomer. HRMS: (ESI+) C 11 H 17 F3NO4 + Calculated value: 284.1104, measured value: 284.1102 (mass deviation -0.8 ppm).

[0163] Preparation of (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride (1:1) (compound 14, HCl salt) in ethyl acetate or dioxane (steps 1-6) Procedure in ethyl acetate: (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid, i.e., compound 13 (20 g, 71 mmol, 1.0 equivalent), was mixed with ethyl acetate (309 mL, 309 mmol, 4.3 equivalent) containing hydrochloric acid (1 mol / L) and stirred at 20 °C. The mixture was heated to 50 °C for at least 1 hour and stirred for 20 hours. The reaction completion of the sample was analyzed by UPLC (target: no more than 1% of compound 13). The mixture was cooled to 10 °C for at least 1 hour and stirred. The solid was collected by filtration, washed with ethyl acetate (100 mL, 5 mL / g compound 13), and washed twice with ethyl acetate (50 mL, 2.5 mL / g compound 13), and dried in a vacuum oven at 45 °C to give (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride (1:1).

[0164] Procedures in dioxane: (2S,4R)-1-(tert-butoxycarbonyl)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid, i.e., compound 13 (141 g, 498 mmol, 1.0 equivalent), was combined with dichloromethane (850 mL, 6 mL / g compound 13) and stirred at 25 °C. 1,4-Dioxane (500 mL, 2000 mmol, 4.0 equivalent) containing hydrochloric acid (4 Mol / L) was added over at least 1 hour. The mixture was then stirred for 22 hours. The reaction completion of the sample was analyzed by UPLC (target: no more than 1% compound 13). The slurry was transferred to an individual container and concentrated to remove volatiles. Ethyl acetate (700 mL, 5 mL / g compound 13) was added and stirred for at least 15 minutes. The solid was collected by filtration. The wet filter cake was washed three times with ethyl acetate (300 mL, 2.1 mL / g compound 13). The solid was dried in a vacuum oven at 40°C to obtain (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride (1:1).

[0165] 1 H NMR (400 MHz, DMSO- d 6 , 298K): δ 10.52 (br s, 2H), 4.41 (t, 1H), 3.64 (dd, 1H), 3.47 (dtd, 1H), 3.21 (dd, 1H), 2.46 - 2.30 (m, 2H). 19 F NMR (376MHz, DMSO- d 6 , 298K): δ -69.61 (d,J = 9.4 Hz). 13 C NMR (101 MHz, DMSO- d 6 , 298K):δ 168.87, 126.52 (q, J = 277.8 Hz), 58.57, 43.70 (d, J = 3.1 Hz), 39.84 (partially overlaps with DMSO signal), 27.52 (d, J = 2.6 Hz). HRMS: (ESI+) C6H9F3NO2 + Calculated value: 184.0580, Measured value: 184.0579 (mass deviation -0.5 ppm). PXRD patterns of different batches of the compound 14HCl salt were determined, and two different PXRD spectra were observed (see...). Figure X (and Y), where the peaks observed in the table below (each peak ±0.2°2θ).

[0166] PXRD peaks and spectrum of compound 14 HCl salt

[0167] PXRD peaks and spectrum of compound 14 HCl salt

[0168] Preparation of (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 14, free form) (steps 1-7) (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride, i.e., compound 14 (50.00 g, 223 mmol, 1 equivalent), was added to the reaction vessel, followed by acetone (150 mL, 4 L / kg) and water (50 mL, 1 L / kg). 4-Methylmorpholine (24.7 mL, 224 mmol, 1.00 equivalent) was slowly added over 1 to 2 hours. Note: The slurry thickened and may stall. The mixture was stirred for 2 hours, followed by filtration. The filter cake was washed twice with a 4:1 acetone:water mixture (125 mL, 2.5 L / kg). The solid was dried overnight (16 hours) at 70°C in a vacuum oven to obtain the desired product: (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid, also known as (2S,4R)-4-(trifluoromethyl)pyrrolidine-1-onium-2-carboxylate; 93% to 95% yield, 96.7% to 98.83% purity.

[0169] 1 H NMR (600 MHz, D2O, 298K): δ 4.27 (dd, J = 8.57, 7.01 Hz, 1H), 3.73(dd, J = 12.93, 8.71 Hz, 1H), 3.52 (dd, J = 12.93, 6.19 Hz, 1H), 3.35 (m, 1H), 2.53 (ddd, J = 14.41, 8.57, 6.10 Hz, 1H), 2.41 (ddd, J = 14.40, 8.54, 7.01 Hz, 1H). 19 F NMR (400 MHz, D2O, 298K): δ -71.44 (s). 13 C NMR (151 MHz, D2O, 298K): δ173.0, 126.2 ( 1 J CF = 277.0 Hz), 61.1, 44.5 ( 3 J CF = 3.0 Hz), 40.8 ( 2 J CF = 29.4 Hz), 28.6 Hz 3 J CF = 2.5 Hz). HRMS: (ESI+) C6H9F3NO2 + Calculated value: 184.0580, measured value: 184.0575 (mass deviation -2.7 ppm).

[0170] Determination of PXRD of free acid of compound 14 (see Figure 10 ), and the peaks in the table below were observed.

[0171] Preparation of (2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid di-tert-butyl ester (compound 16) (2R)-4-oxopyrrolidine-1,2-dicarboxylic acid di-tert-butyl ester, i.e., compound 15 ((2R)-4-oxopyrrolidine-1,2-dicarboxylic acid di-tert-butyl ester) (40 g, 1.0 equivalent) was combined with tetrahydrofuran (240 mL, 6 L / kg compound 15) and stirred at 25 °C. Trifluoromethyltrimethylsilane TMSCF3 (29.7 mL, 1.5 equivalent) was added, and the resulting solution was cooled from 0 °C to 15 °C (the reaction below 0 °C has better exothermic control). Tetrabutylammonium fluoride TBAF (9.06 g, 0.26 equivalent) was mixed with tetrahydrofuran (40 mL, 1 L / kg compound 15) and added dropwise to the previous reaction mixture (high exothermic reaction was observed at the first drop (approximately 10 °C to 15 °C)). Wash with tetrahydrofuran (40 mL, 1 L / kg compound 15) and stir at 25 °C for 16 h. Samples of the reaction were taken for analysis (target complete conversion). The reaction was quenched by adding an aqueous solution of ammonium chloride (NH4Cl) (360 mL, 10 wt% saline solution, 9.0 L / kg compound 15), followed by the addition of methyl tert-butyl ether (200 mL, 5 L / kg compound 15) and stirring for 30 min. Stirring was stopped and the layers were allowed to settle. The organic phase was removed and washed with a second portion of methyl tert-butyl ether (200 mL, 5 L / kg compound 15). The organic phases were combined and subsequently concentrated by vacuum distillation at 0.3 bar (internal temperature of the reaction mixture approximately 30 °C) to approximately 5 L / kg. Isopropanol (400 mL, 10 L / kg compound 15) was then added to the mixture, and distillation was continued to achieve a reaction volume of approximately 5 L / kg. A second addition of isopropanol (400 mL, 8 L / kg of compound 15) was made, and the distillation process was repeated following the same procedure, ending at 5 L / kg. Water (200 mL, 4 L / kg to 5 L / kg of compound 15) was slowly added, and the mixture was stirred at 70°C for 30 minutes to obtain a solution (if necessary, 0 L / kg to 1 L / kg of isopropanol was added to obtain a clear solution). This solution was cooled to 25°C over 2 hours, then slowly cooled to 0°C (at a rate of 0.2 K / min) and held at 0°C for at least 30 minutes. The solid was collected by filtration, washed twice with a 1:1 mixture of 2 L / kg isopropanol:water, and dried in a vacuum oven at 50°C for 12 hours to give 36.2 g of (2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester, i.e., compound 16 (73% to 88% yield). Note: In 1 H, 19 F and 13 In the C NMR spectrum, two sets of resonances were observed due to the presence of rotational isomers in the solution. 1 H NMR (400 MHz, DMSO- d6 , 298K): δ 6.51 (s, 1H), 4.31 (ddd, J = 16.9, 9.5, 2.0 Hz, 1H), 3.50 (dd, J= 12.0, 5.7 Hz, 1H), 2.67 – 2.41 (m, 1H), 2.11 – 2.03 (m, 1H), 1.45 – 1.34(m, 18H). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -79.61, -79.65. 13 C NMR (101 MHz, DMSO- d 6 , 298K): δ 170.8, 170.5, 153.7, 127.6, 124.7, 81.5, 81.4, 80.2, 80.0,78.6, 77.9, 77.6, 59.1, 58.9, 54.0, 53.8, 38.1, 37.3, 28.8, 28.6, 28.4, 28.3,26.3. HRMS: C 15 H 25 F3NO5 + Calculated value: 356.1680, measured value: 356.1693 (mass deviation 3.79 ppm).

[0172] Preparation of (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester (compound 17) (2R)-4-hydroxy-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid di-tert-butyl ester, i.e., compound 16 (10.6 g, 1.0 equivalent), was combined with acetonitrile (45 mL, 4 L / kg compound 16) and stirred at 25 °C. Pyridine (12 mL, 5 equivalent) was added, and the resulting solution was heated to 30 °C to 40 °C. Trifluoromethanesulfonic anhydride (7.4 mL, 1.5 equivalent) was added dropwise (exothermic reaction observed (approximately 10 °C)), and the mixture was stirred at 40 °C for 16 to 20 hours. The reaction was sampled for IPC (intrinsic conversion of the target). The reaction was cooled to 0 °C to 5 °C and quenched by dropwise addition of purified water (32 mL, 3.0 L / kg compound 16), with stirring maintained for 30 minutes, and methyl tert-butyl ether (85 mL, 8.0 L / kg compound 16) was added. The mixture was heated to 25 °C and stirred for 30 minutes. Stop stirring and allow each layer to settle. Remove the aqueous phase and wash the organic phase with an aqueous citric acid solution (64 mL, 2% wt% citric acid solution, 6.0 L / kg compound 16), followed by a second wash with an aqueous sodium bicarbonate solution (64 mL, 7% wt% sodium bicarbonate solution, 6.0 L / kg compound 16), and then twice with purified water (32 mL, 3.0 L / kg compound 16) following the same procedure. Concentrate the organic phase by vacuum distillation at 0.3 bar (internal temperature of the reaction mixture approximately 30°C to 40°C) until approximately 2.5 L / kg is reached. Then add methanol or isopropanol (50 mL, 5 L / kg compound 16) to the mixture and continue distillation to approximately 2.5 L / kg reaction volume. Add isopropanol a second time (50 mL, 5 L / kg compound 16) and repeat the distillation process following the same procedure, ending distillation at 2.5 L / kg. Analyze the solvent content of the sample, aiming for iPrOH to be no less than 96% relative to ACN and MTBE. If the target is not met, repeat the distillation cycle until specifications are met. The product is separated as a mixture of the positional isomer (compound 17, i.e., di-tert-butyl (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid) and 0.5% to 20% di-tert-butyl (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid) in isopropanol (or methanol) solution. Expected molar yield: 75% to 90%. The solution is used in the next step without further treatment.

[0173] Alternative procedures for preparing (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester (compound 17) using BAST or DAST: Compound 16 (106 g, 1.0 equivalent) was combined with methyl tert-butyl ether (10 L / kg compound 16) and stirred at (-10°C) to 0°C. Bis(2-methoxyethyl)aminosulfur trifluoride BAST (1.7 equivalent) was slowly added to the mixture at (-10°C) to 0°C, and the resulting solution was heated to 20°C to 30°C and stirred for 16 to 20 hours. The reaction was sampled for analysis to determine complete conversion. The reaction was cooled to 0°C to 10°C and quenched by adding an aqueous sodium bicarbonate solution (7% by weight, approximately 16.0 L / kg compound 16) to adjust the pH to 7 to 8. The mixture was heated to 25°C and stirred for 30 minutes. Stirring was stopped and the layers were allowed to settle. The aqueous phase was removed, and the organic phase was washed with water (4.0 L / kg compound 16). The organic phase was concentrated by vacuum distillation until approximately 1 L / kg to 2 L / kg was achieved. Heptane (10 L / kg of compound 16) was then added to the mixture, and the mixture was filtered through a silica gel pad (0.5 g / g) using heptane / MTBE (50:1) as the eluent. The filtrate was concentrated to approximately 1 L / kg to 2 L / kg. The product was separated as a mixture of the positional isomer ((2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester, i.e., compound 17, and 0.5% to 20% (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester) in heptane solution. Expected molar yield: 75% to 90%. The solution was used in the next step without further treatment.

[0174] Note: The above procedure can be performed using (diethylamino)sulfur trifluoride (DAST) instead of BAST, and MTBE or DCM can be used as the solvent.

[0175] The solution sample was concentrated to dryness and purified by column chromatography using a solvent mixture of heptane:ethyl acetate (80:20) and a RediSep Gold® silica gel disposable rapid column for characterization purposes.

[0176] Note: In 1 H, 19 F and 13 In the C10 NMR spectrum, two sets of resonances were observed due to the presence of rotational isomers in solution. A minor isomer, (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester (indicated as minor where possible), was also observed in compound 17, and both were separated together. The two isomers were treated together in the next step to give the same product.

[0177] 1 H NMR (400 MHz, DMSO- d6 , 298K): δ 7.22 (d, J = 31.4 Hz, minor), 6.78 -6.51 (m, 1H), 5.13 - 4.94 (m, 1H), 4.70 (dd, J = 12.3, 4.8 Hz, minor), 4.29 (dtq, J = 5.8, 4.0, 1.7 Hz, 2H), 2.65 (d, J = 17.4 Hz, minor), 1.46 - 1.36 (m, 18H). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -61.22 (minor), -63.78, -63.81. 13 C NMR (101 MHz, DMSO-) d 6 , 298K): δ 170.1, 168.2, 167.9, 153.4, 153.0, 151.2, 135.0,131.8, 131.7, 131.7, 131.7, 131.5, 131.5, 131.4, 131.2, 131.2, 130.9, 130.9,130.5, 130.2, 125.8, 125.2, 123.2, 123.1, 122.6, 120.5, 120.4, 120.0, 117.8,107.8, 107.7, 107.3, 106.9, 106.6, 106.5, 106.5, 106.2, 106.0, 82.7, 82.5,82.3, 80.7, 80.6, 68.0, 67.8, 60.0, 51.3, 32.9, 32.0, 31.7, 29.1, 28.7, 28.5,28.3, 28.3, 28.2, 28.2, 27.7, 22.9, 14.7. HRMS: C 15 H 23 F3NO4 + Calculated value: 338.1574, measured value: 338.1574 (mass deviation -0.015 ppm).

[0178] Preparation of (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid di-tert-butyl ester (compound 18) At 20°C to 30°C, acetic acid (0.3 to 0.5 equivalents) is added to a solution of (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester, i.e., compound 17, and 0% to 20% (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester (90 g, 1.0 equivalent) in methanol (6 L / kg to 10 L / kg compound 17 + (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester) or isopropanol (2 L / kg to 3 L / kg compound 17 + (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester). Add Raney nickel (0.4 w / w to 1 w / w), and purge the system three times with nitrogen at 0.4 MPa, followed by three times with hydrogen at 0.4 MPa, adjusting the pressure to 0.6 MPa to 0.9 MPa with hydrogen. Stir the resulting slurry at 25°C to 35°C for 16 to 24 hours. (Note: Raney nickel can be reduced to 25% wet catalyst (60% w / w catalyst + 40% water), and the pH of the catalyst can be adjusted with acetic acid before use; therefore, the addition of AcOH is not required). Sample the reaction mixture for analysis (target: complete conversion). Filter the reaction mixture and concentrate to dryness. Add methyl tert-butyl ether (5.0 L / kg compound 17 + (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester), stir the solution at 25°C, and wash with an aqueous sodium bicarbonate solution (7% by weight sodium bicarbonate solution, 3.0 L / kg compound 17 + (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester). Maintain stirring for 30 minutes. Stop stirring and allow each layer to settle. Remove the aqueous phase and wash the organic phase with water (2.0 L / kg compound 17 + (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester). If necessary, further distill to achieve a water content not exceeding 0.1%. (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester, namely compound 18, was obtained with a separation yield of 93%.

[0179] Crystallization conditions: When isopropanol is used as the solvent for this reaction, after filtration of the catalyst, the solution is heated at 50°C and water (2.0 L / kg of compound 17 + (2R)-4-(trifluoromethyl)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylic acid di-tert-butyl ester) is slowly added at 50°C. The mixture is cooled to 5°C to 10°C to begin crystallization (if necessary, seed crystals are added at about 30°C). The compound is separated by filtration.

[0180] Characterization of (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid ditert-butyl ester, i.e., compound 18. Note: Due to the N1-C15 amide bond, the sample contains a minor rotational isomer, which accounts for approximately 11% of the sample.

[0181] 1 H NMR (600 MHz, DMSO- d 6 , 298K): δ 4.21-4.17 (om, 1H), 3.77-3.73 (om, 1H), 3.40-3.30 (m, 1H), 3.29-3.21 (om, 1H), 2.64 (dt, J=13.29, 9.00 Hz, 1H), 2.59 (dt, J=13.21, 9.00 Hz, minor), 1.88-1.81 (m, 1H), 1.42 (s, 9H), 1.41 (s, minor), 1.39 (s, minor), 1.36 (s, 9H). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -69.65(d, J= 0.02 Hz), -69.70 (d, J= 0.02 Hz, minor). 13 C NMR (151 MHz, DMSO- d 6 , 298K):δ 170.6, 170.2 (minor), 152.9 (minor), 152.7, 126.6 ( 1 J CF = 277.1 Hz), 80.9, 80.7 (minor), 79.5 (minor), 79.3, 58.7 (minor), 58.4, 45.4 ( 3 J CF =3.00 Hz), 40.1 ( 2 J CF =27.9 Hz (minor), 39.3 (overlapping with solvent), 29.3, 28.3 (minor), 27.9 (minor), 27.7, 27.4. om = overlapping multiplets. HRMS: (ESI+) C 15 H 25 F3NO4 +Calculated value: 340.1730, measured value: 340.1733 (mass deviation 0.79 ppm).

[0182] Reference: J. Org. Chem. 2003, 68, 9, 3614-3617.

[0183] Preparation of (2R,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl hydrochloride (1:1) (Compound 3) (2R,4R)-4-(trifluoromethyl)pyrrolidine-1,2-dicarboxylic acid di-tert-butyl ester, i.e., compound 18 (10.00 g, 29.46 mmol, 1.00 equivalent), was added to the reaction vessel, followed by dichloromethane (50 mL, 5 L / kg compound 18). 1,4-Dioxane containing hydrochloric acid (30 mL, 120 mmol, 4.073 equivalent) was slowly added to the mixture. The reaction mixture was stirred for 3 hours. The mixture was concentrated to remove volatiles. Methyl tert-butyl ether (MTBE, 50 mL, 5 L / kg compound 18) was added to the mixture, followed by concentration to remove volatiles. Methyl tert-butyl ether (50 mL, L / kg compound 18) was added and stirred for 30 minutes to 1 hour. The resulting slurry was filtered. The filter cake was washed twice with 20 mL (2 L / kg compound 18) of methyl tert-butyl ether. The solid was dried overnight (16 hours) at 50°C in a vacuum oven to obtain the desired product (2R,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl hydrochloride (1:1), i.e., compound 3; 79.5% yield, 90.2% purity.

[0184] Note: Alternative procedures can be used, where dioxane containing HCl can be replaced with ethyl acetate or isopropyl acetate containing HCl. Dichloromethane can also be replaced with the same solvent (ethyl acetate or isopropyl acetate).

[0185] Alternative procedures using EtOAc or IPAc containing HCl as solvents: At 10°C to 25°C, EtOAc or IPAc containing HCl (4.5 equivalents) was added dropwise to a solution of Compound 18 (1 equivalent) in EtOAc (or IPAc) (1.0 L / kg to 2.0 L / kg of Compound 18). The resulting mixture was stirred at 10°C to 25°C for 3 to 24 hours, and then cooled to 0°C to 5°C and maintained at that temperature for at least 30 minutes. Compound (2R,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl hydrochloride (1:1) precipitated over time and was separated by filtration and carefully washed with cold EtOAc or cold IPAc. (Note: Adding cold heptane during precipitation can help remove impurities). (2R,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl hydrochloride (1:1) was separated as a white solid in yields of 69% to 84%. Product characterization: The sample contains minor impurities, which account for approximately 3% of the sample. 1 H NMR (600 MHz, DMSO- d 6 , 298K): δ 10.25 (br, 2H), 4.46 (t, J = 8.29 Hz, 1H), 3.57 (dd, J = 11.90,9.49 Hz, 1H), 3.50 (m, 1H) 3.31 (dd, J = 11.94, 7.07 Hz, 1H), 2.61 (dt, J =13.56, 8.39 Hz, 1H), 2.08 (dt, J = 13.53, 8.12 Hz, 1H), 1.47 (s, 9H). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -69.39 (d, J = 0.03 Hz). 13 C NMR (151 MHz, DMSO- d 6 ,298K): δ 168.9 (minor), 166.5, 126.3 (1 JCF= 277.6 Hz), 83.6, 58.9, 58.6 (minor), 43.5, 39.9, 27.8, 27.4. HRMS: (ESI+) C 10 H 17 F3NO2 +Calculated value: 240.1206, measured value: 240.1206 (mass deviation -0.003 ppm).

[0186] The PXRD of compound 3, namely (2R,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl hydrochloride (1:1), was determined. Figure 18 ), and the following peaks were observed.

[0187] The PXRD of compound 3 in its free (non-salt) form was also determined. Figure 17 ), and the following peaks were observed.

[0188] Preparation of (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester (compound 4) To a flask, add isopropanol (30 mL, 2 V), (2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyric acid, i.e., compound 2 (11.8 g, 62.6 mmol, 1.15 equivalents), (2R,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl hydrochloride (1:1), i.e., compound 3 (15.0 g, 54.4 mmol, 1.0 equivalents), and N-methylmorpholine (21.6 mL, 196 mmol, 3.6 equivalents), and maintain at 20 °C. To a flask, add diphenylphosphine chloride (13.0 mL, 68.0 mmol, 1.25 equivalents), and maintain the internal temperature at 20 °C. Stir the mixture overnight. Add isopropanol (15 mL, 1 volume) all at once at 20 °C. Add water (60 mL, 4 volumes) after 1 hour at 20 °C. The slurry was filtered, and the filter cake was washed twice with isopropanol (12 mL, 0.8 times the volume) / water (18 V, 1.2 times the volume). The filter cake was dried at >50 °C to give (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester, compound 4 (19.6 g, 87% yield), as a white crystalline solid. 1 H NMR (600 MHz, DMSO- d 6) δ 7.58 (d, J =9.77 Hz, minor), 7.30 (d, J = 9.68 Hz, 1H), 6.84 (br d, J= 9.13 Hz (minor), 4.88 (dd, J = 9.96, 3.14 Hz (minor), 4.29 (d, J = 9.65 Hz, 1H), 4.27 (dd, J = 8.86, 6.76Hz, 1H), 4.24 (dd, J = 10.47, 8.30 Hz, 1H), 4.16 (br d, J = 8.59 Hz (minor), 4.07 (dd, J = 12.72, 9.27 Hz (minor), 3.93 (d, J = 9.67 Hz, minor), 3.51-3.60 (om, 1H), 3.55 (s, minor), 3.54 (s, 3H), 3.44 (m, 1H), 3.31 (m, minor), 3.19 (dd, J = 12.55, 7.05 Hz (minor), 2.70 (dt, J = 14.27, 10.03 Hz (minor), 2.59 (dt, J = 13.17, 8.96 Hz,1H), 2.12 (ddd, J = 14.26, 4.62, 3.36 Hz (minor), 1.79 (ddd, J = 13.35, 8.70, 6.84Hz, 1H), 1.43 (s, minor), 1.34 (s, 9H), 0.94 (s, 9H), 0.93 (s, minor). 13 C NMR: (151 MHz, DMSO- d 6) δ 170.3 (minor), 169.7, 169.6 (minor), 169.6, 157.1 (minor), 156.8, 126.4 ( 1 J CF = 277.1 Hz), 127.0 Hz 1 J CF =278.2 Hz (minor), 81.8 (minor), 80.4, 58.9 (minor), 58.8, 58.3, 57.8 (minor), 51.7 (minor), 51.4, 46.3, 46.1 (minor), 44.5, 40.6 (minor) 2 J CF = 28.2 Hz), 38.2 ( 2 J CF = 27.8 Hz), 34.2 (minor), 34.1, 34.0 (minor), 29.7 (minor), 27.6, 27.3 (minor), 27.2, 26.3 (minor), 26.0. 19 F NMR: (376 MHz, DMSO- d 6) δ -70.06, -70.11 (minor), -70.18 (minor). HRMS (ESI) C 18 H 29 F3N2O5[M+H] + Calculated value: 411.2101; Measured value: 411.2105.

[0189] Determination of PXRD of compound 4 ( Figure 14 ), and the peaks in the table below were observed.

[0190] Determination of PXRD of compound 2 ( Figure 13 ), and the peaks in the table below were observed.

[0191] Example Example 1 Preparation of potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate (compound 6) At 20°C, MTBE (10 mL, 2.5 times its volume), (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester, i.e., compound 4 (4.0 g, 9.6 mmol, 1.0 equivalent), and water (0.21 mL, 12 mmol, 1.2 equivalent) were added to a flask. A potassium tert-butoxide KOt-Bu solution (20 wt% in THF, 7.0 mL, 12 mmol, 1.2 equivalent) was added to the flask, maintaining the internal temperature at 20°C. The mixture was stirred overnight. Methanol (2.0 mL, 0.5 times its volume) was added in a single batch at 20°C. The mixture was stirred. The slurry was filtered, and the filter cake was washed with MTBE (6.7 mL, 1.7 times its volume) / methanol (1.3 mL, 0.3 times its volume). The filter cake was dried at >60°C to give potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate, compound 6 (3.39 g, 87% yield), which was a white crystalline solid. 1 H NMR (600 MHz, CD3OD) δ 4.56 (dd, J =6.81, 4.59 Hz, 1H, E ), 4.51 (dd, J = 8.71, 3.97 Hz, 1H, Z ), 4.30 (s, 1H, Z ), 4.27(s, 1H, E ), 4.24 (br, minor), 4.03 (dd, J = 10.77, 8.23 ​​Hz, 1H, Z ), 3.96 (dd, J =10.67, 6.72 Hz, 1H, Z ), 3.87 (dd, J = 12.57, 8.67 Hz, 1H, E ), 3.68 (br s, minor), 3.65 (s, 3H, Z ), 3.63 (s, 3H, E ), 3.59 (dd, J = 12.62, 6.91Hz, 1H, E ), 3.29 (m, 1H, Z ), 3.15 (m, 1H, E), 2.34-2.40 (om, 2H, E ), 2.28 (m, 1H, Z ), 2.23 (m, 1H, Z ),1.06 (s, 9H, Z ), 0.97 (s, 9H, E ). 13 C NMR (151 MHz, CD3OD) δ 178.5 ( Z ), 177.9( E ), 177.4 (minor), 172.4 ( E ), 172.3 (minor), 171.9 ( Z ), 159.5 ( Z ), 158.7 ( E ), 158.4 (minor), 128.6 ( 1 J CF = 276.3 Hz, E ), 128.5 ( 1 J CF = 276.6 Hz, Z ), 63.9 ( E ), 62.7( Z ), 61.1 (minor), 60.8 (minor), 60.7 ( Z ), 60.5 ( E ), 53.1 (minor), 52.9 ( Z ),52.8 ( E ), 48.2 ( Z ), 46.8 ( E ), 43.3 ( 2 J CF = 28.8 Hz, Z ), 41.1 ( 2 J CF = 29.0 Hz, E ),37.2 ( E ), 36.8 (minor), 36.5 ( Z ), 32.4 (minor), 32.3 ( E ), 30.3 ( Z), 27.1 ( Z ),26.9 ( E ), 26.8 (minor). 19 F NMR (376 MHz, CD3OD) δ -72.90, -73.15. HRMS (ESI)C 14 H 21 F3N2O5[M+H] + Calculated value: 355.1475; measured value: 355.1471.

[0192] Determination of PXRD ( Figure 16 ), and the peaks in the table below were observed.

[0193] Example 2 Preparation of ethyl acetate solvate of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (ethyl acetate solvate of compound I) Compound I shown in the above formula is isolated as an EtOAc solvate.

[0194] 40 mL of 2-butanone and potassium (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate, i.e., compound 6 (4.04 g, 9.98 mmol), were charged into a 100 mL container equipped with a top stirrer, and the slurry was stirred at 20 °C. N 1-Methylmorpholine (3.3 mL, 30 mmol, 3 equivalents), 2-chloro-1-methylpyridine p-toluenesulfonate (2.63 g, 11.9 mmol, 1.2 equivalents), (2S)-2-amino-3-[(3S)-2-oxopyrrolidone-3-yl]propionamide hydrochloride (1:1), namely compound 7 (2.36 g, 11.37 mmol, 1.15 equivalents) and water (1.2 mL). The reaction was stirred at 20°C for 4 hours to obtain methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound 8, which can be used without separation.

[0195] A sample of compound 8 was isolated for characterization. Characterization of compound 8: 1 H NMR (600 MHz, DMSO- d 6) δppm 0.95 (s, 10 H), 1.18 (t, J =7.34 Hz, 2 H), 1.45 - 1.52 (m, 1 H), 1.57 -1.67 (m, 1 H), 1.89 - 1.98 (m, 1 H), 2.08 - 2.16 (m, 2 H), 2.21 - 2.28 (m, 1H), 2.39 - 2.46 (m, 1 H), 3.00 - 3.17 (m, 3 H), 3.34 - 3.40 (m, 1 H), 3.52 (s, 3 H), 4.15 (br d, J =8.80 Hz, 1 H), 4.25 (ddd, J =12.10, 8.80, 3.48 Hz, 1 H),4.51 (dd, J =8.07, 5.69 Hz, 1 H), 7.04 (s, 1 H), 7.25 (br d, J =8.62 Hz, 1 H),7.33 (s, 1 H), 7.54 (s, 1 H), 8.28 (d, J =8.80 Hz, 1 H). 13 C NMR (151 MHz, DMSO- d 6) δ ppm 9.03 (s, 1 C), 26.64 (s, 3 C), 27.88 (s, 1 C), 28.79 (s, 1 C), 34.57 (s, 1 C), 34.94 (s, 2 C), 37.70 (s, 1 C), 41.76 (s, 1 C), 46.03 (s, 1C), 50.83 (s, 1 C), 51.97 (s, 1 C), 59.20 (s, 1 C), 59.40 (s, 1 C), 128.49 (s, 1 C), 157.46 (s, 1 C), 170.13 (s, 1 C), 171.36 (s, 1 C), 173.89 (s, 1 C), 179.07 (s, 1 C). Determination of PXRD of compound 8 ( Figure 19 ), and the peaks in the table below were observed.

[0196] The solvent from the crude reaction mixture in the first step above was replaced with ethyl acetate (40 mL) by vacuum distillation. Distillation continued until the water content was <0.2% by weight. The slurry was cooled to 0°C and loaded into... N 1,3-methylimidazole (4 mL, 50.2 mmol, 5 equivalents). Trifluoroacetic anhydride (3.5 mL, 25 mmol, 2.5 equivalents) was added over 30 minutes, and the reaction was stirred at 0 °C for 1 hour. The reaction was quenched with a mixture of citric acid monohydrate (8.42 g, 39.67 mmol, 4 equivalents) and sodium chloride (6.22 g, 106.5 mmol, 10.7 equivalents) in water (40 mL). The phases were separated, and the aqueous layer was back-extracted with ethyl acetate (40 mL). The combined organic layers were washed with a mixture of dipotassium hydrogen phosphate (13.93 g, 80 mmol, 8 equivalents) in water (40 mL), followed by washing with a 14% sodium chloride aqueous solution (20 mL). The organic layer was distilled under vacuum to 20 mL and maintained at 45 °C. The solid product {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate ethyl acetate solvate, namely compound I ethyl acetate solvate (3.70 g, 7.32 mmol, 73% yield), was isolated from a mixture of ethyl acetate and heptane. {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate ethyl acetate solvate: The sample contains the major rotational isomer (approximately 83.2%, shown in...). Figure 1 (in the middle) and due to the N14-C18 amide bond E / Z The minor rotational isomers due to isomerization (approximately 7.0%) and the tertiary rotational isomers due to the N24-C25 urethane amide bond (approximately 9.8%).

[0197] 1 H NMR (600 MHz, DMSO- d 6) δ 9.09 (d, J = 6.90 Hz, minor), 9.02 (d, J= 8.52 Hz, 1H), 7.72 (s, minor), 7.66 (s, 1H), 7.27 (d, J = 8.83 Hz, 1H), 6.95 (d, J =8.96 Hz (minor), 6.85 (br, minor), 4.95 (ddd, J = 10.95, 8.54, 4.95 Hz, 1H), 4.89(q, J = 7.81 Hz, minor), 4.80 (dd, J = 8.52, 3.06 Hz (minor), 4.36 (dd, J = 8.23, 6.29Hz, 1H), 4.15 (d, J = 8.77 Hz, 1H), 4.07 (br, minor), 4.04 (d, J = 8.74 Hz, minor), 3.96 (m, 2H), 3.85 (br, minor), 3.66 (m, minor), 3.52 (s, 3H), 3.50 (s, minor), 3.41 (m, 1H), 3.30-3.35 (m, overlapping with residual water peak, minor), 3.12-3.20 (om, minor), 3.14 (m, 1H), 3.04 (td, J = 9.39, 7.08 Hz, 1H), 2.45 (m, 1H), 2.30 (m, 1H), 2.16(ddd, J = 13.64, 11.03, 4.43 Hz, 1H), 2.05-2.12 (om, 2H), 1.84 (dt, J = 13.61, 7.91 Hz (minor), 1.65-1.73 (om, 2H), 0.94 (s, 9H), 0.89 (s, minor). 13 C NMR (151MHz, DMSO- d 6) δ 177.5 (minor), 177.4, 170.8, 170.4 (minor), 169.8, 169.4 (minor), 156.9, 156.3 (minor), 127.1 ( 1 J CF = 278.4 Hz (minor), 126.9 ( 1 JCF = 277.3 Hz), 119.5, 119.2 (minor), 58.9, 58.5, 58.4 (minor), 51.4, 51.3 (minor), 46.7, 45.3 (minor), 41.2 ( 2 J CF = 27.8 Hz), 39.1 (overlapping with solvent), 37.6, 37.3 (minor), 36.5, 35.1 (minor), 34.3, 34.1, 33.2 (minor), 30.4 (minor), 28.1, 27.3 (minor), 26.8, 26.0, 25.9 (minor). 19 F NMR (376 MHz, DMSO- d 6) δ -70.16, -70.44 (minor), -70.57 (minor). om = overlapping multiple peaks, br = wide signal. HRMS (ESI) m / z [M+H] + C 21 H 31 The calculated value of O5N5F3 is 490.2272 Da, and the measured value is also 490.2272 Da.

[0198] The PXRD pattern of compound I EtOAc solvate is shown in Figure 4 middle.

[0199] Example 3 program: 135 kg of EtOAc, 34.2 kg of heptane, and 25.0 kg of methyl carbamate (form 1) {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate were charged into a suitably sized container at 25 °C, while stirring at 120 rpm. The mixture was then heated to 60 °C and stirred for 10 minutes until a homogeneous solution was obtained. The mixture was then cooled to 45 °C, and 2.78 kg of microcrystalline cellulose (MCC) was subsequently charged. The mixture was then stirred at 45 °C for 30 minutes. After a 4-hour period, an additional 120 kg of heptane was charged, and the mixture was then stirred at 45 °C for 30 minutes. The mixture was then cooled to 20 °C and maintained at this temperature for 12 hours. EtOAc was then removed by constant-volume vacuum distillation using 342 kg of added heptane, maintaining a temperature difference of 25 °C between the reactor and the mixture, and reaching a final internal mixture temperature of 52 °C. The mixture was then cooled again to 25 °C and sampled to determine the EtOAc content. The batch was then reheated to 80 °C and held at this temperature for 6 hours. The mixture was sampled to confirm the consistency of the PXRD with the desired form 1+MCC, and then cooled to 20 °C. The batch was granulated at 20 °C for 1 hour and then filtered. The vessel was rinsed with 68 kg of heptane, and this rinse solution was then applied to the filter cake to wash it. The filter cake was then dried and separated to obtain methyl carbamate in the form of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate 1+MCC.

[0200] Product characterization: Note: Due to the N1-C10 and N16-C17 amide bonds, the sample contains two minor rotational isomers, accounting for approximately 6% and 10% of the sample, respectively. In relevant cases, the less abundant rotational isomer signal is designated as "minor".

[0201] 1 H NMR (600 MHz, DMSO- d 6, 298K): δ 9.11(d, J=6.97 Hz, minor), 9.05 (d, J=8.63 Hz, 1H), 7.75 (s, minor), 7.69 (s, 1H), 7.32 (d, J=8.66 Hz, 1H), 7.01 (d, J=9.16 Hz, minor), 6.90 (br, minor), 4.95 (ddd, J=11.23, 8.63, 4.86 Hz, 1H), 4.88(q, J=7.53 Hz, minor), 4.80 (dd, J=8.16, 2.90 Hz, minor), 4.35 (t, J=7.53 Hz, 1H), 4.14 (d, J=8.78 Hz, 1H), 4.07 (br, minor), 4.04 (d, J=9.10 Hz, minor), 3.98-3.95 (m, 1H), 3.84 (br, minor), 3.65 (d, J=7.06 Hz, minor), 3.52 (s, 3H), 3.49 (s, minor), 3.41 (m, 1H), 3.31 (m, minor), 3.17 (m, minor), 3.13 (t, J=9.11 Hz, 1H), 3.03 (td, J=9.32, 7.17 Hz, 1H), 2.46 (m, 1H), 2.30 (m, 1H), 2.24 (m, minor), 2.16 (ddd, J=13.51, 11.25, 4.28 Hz, 1H), 2.12-2.05 (om, 2H), 1.84 (m, minor), 1.73-1.65 (om, 2H), 0.94 (s, 9H), 0.89 (s, minor). 13 C NMR (151 MHz, DMSO- d 6, 298K): δ 177.5 (minor), 177.4, 170.8, 170.4 (minor), 169.9 (minor), 169.7, 169.3 (minor), 156.9, 156.3 (minor), 155.5 (minor), 127.0 (1JCF = 278.4 Hz), 119.5, 119.2 (minor), 59.4 (minor), 58.9, 58.8 (minor), 58.6 (minor), 58.5, 58.3 (minor), 51.6 (minor), 51.4, 51.3 (minor), 46.8 (minor), 46.7, 45.3 (minor), 41.1 (2JCF = 28.0 Hz). Hz), 39.5 (minor, ov), 39.1, 39.0 (minor, ov), 38.6 (2JCF = 27.8 Hz, minor), 37.6, 37.3 (minor), 36.5, 35.1 (minor), 34.3, 34.2 (minor), 34.1, 33.2 (minor), 30.3 (minor), 28.1, 27.3 (minor), 26.7, 26.0, 25.9 (minor). 19 F NMR (376MHz, DMSO- d 6 (298K): δ -70.17, -70.45 (minor), -70.58 (minor). om = overlapping multiplets, ov = overlap with solvent, br = broad signal. HRMS: (ESI) m / z [M+H] + C 21 H 31 The calculated value of O5N5F3 is 490.2272 Da, and the measured value is 490.2271 Da.

[0202] Additional batches of methyl carbamate 1+ microcrystalline cellulose (90 / 10 wt%) designated as A, B, and C were prepared in a similar manner at a scale of 80 g, and the resulting particle size distribution was analyzed. The D

[10] , D

[50] , and D

[90] values ​​for these batches, in μm, are provided below.

[0203] Additional batches of D-tray 1 to D-tray 3 and E, {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate form 1+ microcrystalline cellulose (90 / 10 wt%) were prepared in a similar manner, and the resulting particles were analyzed.

[0204] Furthermore, batches D-tray 1 through D-tray 3 and E were found to have flow function coefficients of 18.6 and 69.0, respectively. Particle size and cumulative distribution of certain batches, as well as images of compound I form 1+ MCC, are provided. Figures 6 to 9 middle.

[0205] The above data indicate that compound I form 1 with MCC additive can be prepared, which is in the desired form and has the desired particle size distribution suitable for use as a pharmaceutical intermediate.

[0206] Additional characterization data for co-treated compound I and MCC are described below.

[0207] Powder X-ray diffraction (PXRD) and ssNMR data of co-processed form 1 and 10 wt% MCC instrument Powder X-ray diffraction (PXRD): Powder X-ray diffraction analysis was performed using a Bruker AXS D8 Endeavor diffractometer equipped with a Cu radiation source (K-α average). The divergence slit was set to 15 mm for continuous irradiation. Diffraction radiation was detected using a PSD-Lynx Eye detector with a PSD aperture set to 4.10 degrees. The X-ray tube voltage and current were set to 40 kV and 40 mA, respectively. Undesirable wavelengths were filtered out using an energy-dispersive detector and a nickel filter. Data were acquired in an θ-θ goniometer from 3.0 degrees to 40.0 degrees 2θ at Cu wavelengths using a step size of 0.01 degrees and a step time of 1.0 second. The antiscattering screen was set to a fixed distance of 3.0 mm. The sample was rotated at 15 rpm during acquisition. The sample was prepared by placing it in a silicon low-background sample holder and rotating it during acquisition. Data were acquired using Bruker DIFFRAC Plus software, and analysis was performed using EVA diffract Plus software.

[0208] The PXRD data file is not processed before peak finding. The peak finding algorithm in EVA software is used to perform initial peak assignment using selected peaks with a threshold of 1. To ensure accuracy, manual adjustments are made; the output of the automatic assignment is visually checked, and peak positions are adjusted to their maximum values. Generally, peaks with a relative intensity ≥3% are selected. Peaks that are not separated or are consistent with noise are not selected. The typical error associated with peak positions from PXRD, as specified in USP, is at most + / - 0.2°2θ (USP-941).

[0209] Solid-state nuclear magnetic resonance (ssNMR): Placed in Bruker-BioSpin Avance NEO 500 MHz ( 1 On the CPMAS probe of the H-frequency NMR spectrometer 13 Solid-state NMR (ssNMR) analysis was performed on a Bruker-BioSpin Avance III 600 MHz transistor. 1 On the CPMAS probe of the H-frequency NMR spectrometer 19 Solid-state NMR (ssNMR) analysis was performed. The material was encapsulated in a ZrO2 rotor. A magic angle rotation rate of 15 kHz was used. Spectra were acquired at ambient temperature (probe temperature 25 °C).

[0210] The proton decoupled cross-polarized magic angle rotation (CPMAS) experiment was used to collect... 13 Css NMR spectra. A phase-modulated proton decoupling field of 80 kHz–100 kHz was applied during spectrum acquisition. The cross-polarization contact time was set to 2 ms and the cycle delay to 3.5 seconds. The number of scans was adjusted to obtain a sufficient signal-to-noise ratio. Crystallized adamantane was used as the external standard. 13 C CPMAS experiment for reference 13 The C chemical shift scale was used to set its high-field resonance to 29.5 ppm.

[0211] Data collected using proton-decoupled magic angle rotation (MAS) experiments. 19 Fss NMR spectra. A proton decoupling field with phase modulation of 80 kHz–100 kHz was applied during spectrum acquisition. Spectra were acquired with a cyclic delay of 3.5 seconds. The number of scans was adjusted to obtain a sufficient signal-to-noise ratio. External standard trifluoroacetic acid (50% / 50% v / v in H2O) was used. 19 For reference, refer to the FMAS experiment. 19 The F chemical shift scale was used to set its resonance to -76.54 ppm.

[0212] Automated peak picking was performed using Bruker-BioSpin TopSpin version 4.1 software. Generally, a threshold of 5% relative intensity was used for initial peak selection. The output of the automated peak picking was visually inspected to ensure accuracy, and manual adjustments were made as necessary. Although specific solid-state NMR peaks are reported in this paper, these peaks do indeed have ranges due to variations in instrumentation, sample, and sample preparation. This is standard practice in solid-state NMR, stemming from inherent variations in peak position. The typical variability of the chemical shift x-axis value for crystalline solids is approximately ±0.2 ppm. The solid-state NMR peak heights reported in this paper are relative intensities. Solid-state NMR intensities can vary depending on the actual experimental parameter settings and the thermal history of the sample.

[0213] result Powder X-ray Diffraction (PXRD): Powder X-ray diffraction patterns and peak sequences of compound I co-treated form 1 and 10 wt% MCC are shown in [the table / image]. Figure 8A The peaks are listed in the table below.

[0214] PXRD peak list of compound I co-treated form 1 and 10 wt% MCC

[0215] Solid-state nuclear magnetic resonance (ssNMR): Compound I co-treated form 1 with 10% by weight of MCC 13 C and 19 The F ss NMR spectrum is shown in Figure 8B and Figure 8C The corresponding peaks are shown in the table immediately following below. Figure 8B and Figure 8C The peaks marked with # are rotating sidebands.

[0216] Table: Compound I co-treated form 1 with 10% wt% MCC 13 C solid-state NMR peak list

[0217] Table: Compound I co-treated form 1 with 10% wt% MCC 19 F solid-state NMR peak list

[0218] Particle size distribution data of Compound I Form 1 and Compound I Co-treatment Form 1 with 10 wt% MCC PSD method Both types of materials were determined using the general method outlined below. This laser diffraction technique disperses the dried sample powder using compressed air. Three parameters were modified in this method to meet certain quality criteria defined therein. Lenses were changed to measure the appropriate particle size range. Sample mass and sled speed were two parameters modified to obtain optimal optical concentration.

[0219] Generally, additional sample mass is used in co-processing Form 1 determinations, but lens selection and sample cell speed may vary depending on the sample.

[0220] Preparation of test samples Prepare three copies of the sample.

[0221] program Invert and rotate the vial to ensure that the material is at the bottom of the vial but not compacted.

[0222] calculate Report the average value of D[v,0.1], D[v,0.5], D[v,0.9] and D[4,3] and %RSD, accurate to two decimal places, based on the three measurements.

[0223] result The particle size ranges of both API (Compound I Form 1) and the co-treated Compound I Form 1 material have been determined. Several parameters can be used to describe the particle size distribution. Commonly accepted parameters are D[v,0.1], D[v,0.5], and D[v,0.9]. These numbers represent the volume-based cumulative distribution. D[v,0.9] indicates that 90% of the sample is smaller than a given value. The D[v,0.5] and D[v,0.9] values ​​are commonly used to describe particle size distribution. The D[v,0.5] and D[v,0.9] values ​​are used to quantitatively describe the particle size of both API (Compound I Form 1) and the co-treated Compound I Form 1.

[0224] The particle size range observed for API (compound I, form 1) was wide. D[v,0.5] ranged from 3 μm to 94 μm, and D[v,0.9] ranged from 17 μm to 250 μm. This is a broad dispersion of particle size values. In addition to these values, the shape of the distribution also varied. The distribution was unimodal (one peak), bimodal (two peaks), and multimodal (more than two peaks). These particle size distributions were uncontrolled during API preparation.

[0225] exist Figures 8D to 8EIn the diagram, the x-axis represents the logarithmic scale of particle size in micrometers. The left y-axis represents the distribution density (in arbitrary units), which is the most common way to observe particle size distribution. The right y-axis represents the cumulative distribution (in percentage units), which directly corresponds to the D[v] value mentioned here. Figures 8D to 8E This demonstrates that the particle size distribution of compound I form 1 is uncontrolled in the absence of MCC.

[0226] Figure 8F The particle size distributions of two different batches of Compound I co-treated Form 1 with 10 wt% MCC are shown: D[v,0.5] = 36 μm and D[v,0.9] = 98 μm (top panel) and D[v,0.5] = 73 μm and D[v,0.9] = 165 μm (bottom panel), both exhibiting unimodal particle size distributions. The particle size of the Form 1 material co-treated with Compound I (co-treated with 10 wt% MCC) was well controlled during its preparation. The particle size was intentionally and controllably varied. D[v,0.5] ranged from 31 μm to 81 μm, and D[v,0.9] ranged from 97 μm to 240 μm. The distribution was predominantly unimodal and controllable, which is beneficial for providing suitable materials for pharmaceuticals.

[0227] Example 4 Preparation of (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid (compound 6') (steps 1-8) Compound 2 (1.41 g, 7.39 mmol, 1.09 equivalents), methanesulfonyl chloride (0.854 g, 7.46 mmol, 1.1 equivalents), and isopropyl acetate (22 mL, 15 mL / g compound 14) were combined and stirred at 20 °C. Triethylamine (2.36 mL, 16.9 mmol, 2.5 equivalents) was added at a rate that kept the reaction temperature below 25 °C, and the resulting mixture was stirred for 60 minutes. In a separate container, (2S,4R)-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid hydrochloride, i.e., compound 14 (1.5 g, 6.8 mmol, 1.0 equivalents), was combined with water (1.5 mL, 1 mL / g compound 14), stirred at 40 °C until the solid dissolved, and then added to the above reaction mixture at 20 °C. Triethylamine (2.36 mL, 16.9 mmol, 2.5 equivalents) and water (1.5 mL, 1 mL / g compound 14) were added to a mixture. The resulting mixture was stirred at 20 °C for 20 h. The reaction completion of the sample (not exceeding 3% compound 14) was analyzed by UPLC. The reaction mixture was quenched by adding water (12 mL, 8 mL / g compound 14) and the mixture was stirred for at least 10 min, followed by sedimentation of each layer. The aqueous phase was removed and collected. The organic phase was extracted with water (12 mL, 8 mL / g compound 14). The combined aqueous phases were loaded into a stirred vessel containing water (23 mL, 15 mL / g compound 14), water containing hydrochloric acid (12.2 mol / L) (1.11 mL, 13.5 mmol, 2.0 equivalents), and seed crystals of the free acid of compound 6 (117 mg, 0.33 mmol, 0.049 equivalents) after 4 h at 25 °C. The mixture was stirred at 25°C for 16 hours. The solid was collected by filtration and washed with water (11 mL, 7 mL / g compound 14). The solid was dried in a vacuum oven at 60°C to give (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid, compound 6, as a crystalline solid.

[0228] Compound 6 is a free acid. Note: In 1 H, 19 F and 13 In the C NMR spectrum, due to E and Z The amide rotational isomer exists in solution, and two sets of resonances were observed. Only the resonances of the major rotational isomer (89%) are listed here. 1 H NMR (400 MHz, DMSO- d 6, 298K): δ 12.76 (s, 1H), 7.24 (d, J = 8.8 Hz, 1H), 4.41 (dd, J = 9.0,5.0 Hz, 1H), 4.17 (d, J = 8.9 Hz, 1H), 3.94 (d, J = 7.1 Hz, 2H), 3.53 (s,3H), 3.45 - 3.27 (m, 1H), 2.43 - 2.28 (m, 1H), 2.26 - 2.11 (m, 1H), 0.97 (s,9H). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -70.15 (d, J = 9.1 Hz). 13 C NMR (101 MHz, DMSO- d 6 , 298K): δ 172.46, 169.90, 156.95, 126.94 (q, J = 278.1 Hz), 58.84,57.88, 51.53, 46.36, 41.07 (q, J = 27.9 Hz), 34.51, 27.75, 26.15. HRMS: (ESI+)C14H22F3N2O5+ Calculated value: 355.1475, Measured value: 355.1478 (mass deviation +0.8 ppm).

[0229] The PXRD of crystalline compound 6 (in its free acid form) was determined, and it was provided in... Figure 15 Among them, the following peaks were observed.

[0230] Example 5 Preparation of methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound 8 Compound 6' (25.4 g, 69.7 mmol, 1.0 equivalent) was combined with methyl ethyl ketone (MEK, 200 mL, 8 L / kg compound 6') and stirred at 25 °C. 2-hydroxypyridine N-oxide (7.91 g, 69.7 mmol, 1.0 equivalent) and triethylamine (17.6 g, 24.3 mL, 0.174 mol, 2.50 equivalent) were added, and the resulting solution was stirred for 5 minutes. Compound 7 (17.2 g, 80.2 mmol, 1.15 equivalents) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI hydrochloride, 20.1 g, 0.105 mol, 1.50 equivalents) were added, washed with water (3.8 mL, 0.15 L / kg compound 6') and methyl ethyl ketone (50 mL, 2 L / kg compound 6'), and stirred at 25°C for 16 hours. The reaction was sampled (target: no more than 1% of compound 6'). If the reaction was incomplete, the mixture was stirred for a further period. The reaction was quenched by adding an aqueous NaCl solution (100 mL, 14 wt% saline solution, 4.0 L / kg compound 6') while stirring for 30 minutes. Stirring was stopped and the layers were allowed to settle. The lower aqueous phase was removed, and the organic phase was washed with a second aqueous NaCl solution (100 mL, 14 wt% saline solution) following the same procedure. The two aqueous phases were combined and extracted with methyl ethyl ketone (125 mL, 5 L / kg compound 6'), stirred for 5 minutes, and the phases were separated. The organic phase was combined with the previous organic layer, and the aqueous phase was extracted with a second portion of methyl ethyl ketone (125 mL, 5 L / kg compound 6') following the same procedure. All organic phases were combined and then concentrated by vacuum distillation at 0.3 bar (internal temperature of the reaction mixture approximately 30°C) until approximately 5 L / kg was reached. Isopropyl acetate (200 mL, 8 L / kg compound 6') was then added to the mixture, and distillation was continued to reach approximately 5 L / kg of the reaction volume. Isopropyl acetate (200 mL, 8 L / kg compound 6') was added a second time, and the distillation process was repeated following the same procedure until distillation was completed at 5 L / kg. Isopropyl acetate (125 mL, 5 L / kg compound 6') was added and stirred at 25°C. The water content of the sample was analyzed (Karl-Fischer), with a target of no more than 0.2 wt% water and no more than 1 wt% MEK. The resulting organic solution of compound 8 was used in step 3 without further purification.

[0231] Characterization of the product {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound 8: The sample containing the solution of compound 8 was concentrated to dryness and purified by column chromatography using a solvent mixture of dichloromethane:methanol (90:10) and a RediSep Gold® silica gel single-use rapid column for characterization purposes.

[0232] Note: In 1 H and 13 In the 12C NMR spectrum, due to the N5-C9 and N15-C16 amide bonds, the sample contains two minor rotational isomers, accounting for approximately 9% and 7% of the sample, respectively. In relevant cases, the less abundant rotational isomer signal is designated as "minor". 1 H NMR (600 MHz, DMSO- d 6, 298K): δ 8.47(d, J=7.88 Hz, minor), 8.28 (d, J=8.96 Hz, 1H), 7.62 (s, minor), 7.54 (s, 1H), 7.42 (s, minor), 7.33 (s, 1H), 7.25(d, J=8.96 Hz, 1H), 7.04 (s, 1H), 7.01 (s, minor), 6.83 (br, minor) 6.78 (d, J=9.12 Hz, minor), 4.92 (br t, J=5.93 Hz, minor), 4.51 (dd, J=8.26, 5.29 Hz), 4.26(ddd, J=12.16, 8.86, 3.55 Hz, 1H), 4.15 (d, J=8.83 Hz, 1H), 4.10 (d, J=9.08Hz, minor), 4.07 (br, minor) 3.89 - 3.97 (om, 2H), 3.85 (br, minor), 3.62 (m, minor), 3.52 (s, 3H), 3.49 (s, minor), 3.37 (m, 1H), 3.25 (m, minor), 3.17 (m, minor), 3.12 (t, J=9.15 Hz, 1H), 3.03 (td, J=9.85, 7.23 Hz, 1H), 2.43 (m, 1H), 2.33 (m, minor), 2.24 (m, 1H), 2.09 - 2.16 (om, 2H), 2.01 (m, minor), 1.94 (ddd, J=13.70, 12.10, 3.57 Hz, 1H), 1.70 (m, minor), 1.62 (m, 1H), 1.54 (m, minor), 1.49 (ddd, J=13.74, 11.96, 3.66 Hz, 1H), 0.95 (s, 9H), 0.89 (s, minor). 13 C NMR (151 MHz, DMSO- d 6, 298K): δ 178.7 (minor), 178.5, 173.4 (minor), 173.3, 170.8, 170.4 (minor), 169.6, 169.2 (minor), 156.9, 156.0 (minor), 127.0 (1JCF = 278.4 Hz), 58.8, 58.6, 58.3 (minor), 51.4, 51.3 (minor), 51.2 (minor), 50.3, 46.6, 45.5 (minor), 41.1 (2JCF = 28.0 Hz), 39.9, 39.4 (minor, ov), 39.2 (ov), 38.6 (2JCF = 28.5 Hz, minor), 37.6 (minor), 37.1, 35.2 (minor), 34.4, 34.0, 33.5 (minor), 30.7 (minor), 28.2, 27.4 (minor), 27.3, 26.1, 26.0 (minor). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -70.07, -70.43 (minor), -70.48 (minor). om = overlapping multiple peaks, ov = overlap with solvent, br = broad signal. HRMS: (ESI+) C 21 H 33 F3N5O6 + Calculated value: 508.2377, measured value: 508.2377 (mass deviation -0.1 ppm).

[0233] Methyl carbamate (amorphous form) can be characterized by PXRD, and the PXRD pattern is shown below. Figure 24 As shown in the image.

[0234] Examples 5A to 5F provide methyl carbamate in different eutectic solid forms with specified carboxylic acid-containing compounds.

[0235] Example 5A Preparation of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate tartrate cocrystal A solution of methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e. compound 8, in 2-butanone was added to a 100 mL container equipped with a top stirrer (96 mL solution, 81.6 g, having 8.25% by weight, 6.8 g of compound 8). The solution was concentrated to approximately 50 mL (20 mL, 6 L / kg) by vacuum distillation (100 mbar to 200 mbar and (internal temperature 40 °C)). 2-Butanone (20 mL, 3 L / kg) was added, and the solution was concentrated to 50 mL (20 mL, 6 L / kg) by vacuum distillation. The water content (Karl Fischer) of the sample was analyzed, with a target of no more than 1% by weight. The reaction mixture was heated at 45 °C, D-(-)-tartaric acid (4.08 g, 27.2 mmol, 2 equivalents) was added, and the mixture was stirred at 75 °C to bring all substances to a solution state. The solution was cooled to 60°C at a rate of 1°C / min, and then seeded at 60°C with methyl carbamate tartrate (30 mg, 0.046 mmol, 0.005 equivalents). The solid was collected by filtration, washed with 2-butanone (20 mL, 3 mL / kg), and dried in a vacuum oven at 50 °C for 8 hours to obtain 7.76 g of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate tartrate (eutectic).

[0236] Note: This procedure can be performed without distillation using 2-butanone (6 L 2-butanone / kg compound 8) containing amorphous {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate.

[0237] The PXRD pattern of the cocrystal of methyl carbamate tartrate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidin-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate tartrate was determined, and it is shown in... Figure 20 Among them, the following peaks were observed.

[0238] Example 5B Preparation of methyl carbamate maleate cocrystals of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate To a 100 mL container equipped with a top stirrer, 2-butanone (5 L / kg) and n-heptane (1.7 L / kg) containing methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound 8, were added. The reaction mixture was heated at 70 °C, maleic acid (1.45 g, 12.4 mmol, 2 equivalents) was added, and the mixture was stirred at 70 °C for 6 hours. The solution was then cooled to 40 °C at a rate of 0.3 °C / min. Seed crystals were added to the mixture at 40 °C using {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate maleate (20 mg, 0.005 wt%), and the mixture was kept for 1 hour and then cooled to 5 °C at a rate of 0.3 °C / min. The solid was collected by filtration, washed with a 4:1 mixture of 2-butanone and n-heptane (20 mL, 2 mL / kg), and dried in a vacuum oven at 50 °C for 17 hours to give 1.94 g of methyl carbamate maleate cocrystal.

[0239] This eutectic can also be formed in 2-butanone or isopropyl acetate.

[0240] The PXRD pattern of the cocrystal of methyl carbamate maleate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidin-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate was determined and shown in [the diagram]. Figure 21 Among them, the peaks observed in the table below were observed.

[0241] Example 5C Preparation of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate succinate cocrystal A 100 mL container equipped with a top stirrer was loaded with tetrahydrofuran (15 L / kg) containing methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound 8. The reaction mixture was heated at 60 °C, succinic acid (1.16 g, 9.8 mmol, 1 equivalent) was added, and the mixture was stirred at 60 °C for 1 hour. The solution was cooled to 50 °C at a rate of 1 °C / min, followed by the addition of n-heptane (10 L / kg) via syringe over 6 hours, maintained for 1 hour, and then cooled to 5 °C at a rate of 0.3 °C / min. The solid was collected by filtration, washed with n-heptane (50 mL, 10 L / kg), and dried in a vacuum oven at 50 °C for 17 hours to obtain 4.26 g of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate succinate (eutectic, partially crystalline).

[0242] Crystallization: The above-mentioned {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate succinate (eutectic, partially crystalline) was added, and tetrahydrofuran (0.5 L / kg) was added until the solid was almost dissolved (thick paste). The slurry was allowed to stand at 25°C for 2 weeks until a precipitate appeared. The solid was dried at 25°C to maintain crystallinity.

[0243] Note: Crystallization can also occur when using a 1:1 mixture of acetone, 2-butanone, or methyl tert-butyl ether:ethyl acetate as a solvent instead of tetrahydrofuran.

[0244] The PXRD pattern of the cocrystal of methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidin-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate succinate was determined, and it is shown in... Figure 22 Among them, the peaks observed in the table below were observed.

[0245] Example 5D Preparation of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate fumarate cocrystal A 100 mL container equipped with a top stirrer was loaded with tetrahydrofuran (25 L / kg) containing methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound 8. The reaction mixture was heated at 60 °C, and fumaric acid (1.14 g, 9.9 mmol, 1 equivalent) was added and stirred at 60 °C for 16 hours. If it was still a slurry, 4 L / kg water was added at 60 °C. The solution was cooled to 5 °C after 12 hours. The solution was distilled twice under vacuum at 50 °C until the concentration of compound 8 was 6 L / kg. Subsequently, n-heptane (6 L / kg) was added over 12 hours, and the mixture was kept at 45°C to 50°C for 1 hour, followed by cooling to 5°C at a rate of 0.3°C / min. The solid was collected by filtration, washed with n-heptane (2 L / kg), and dried in a vacuum oven at 50°C for 16 hours to give 1.35 g of methyl carbamate fumarate cocrystal.

[0246] Crystallization: Add the above-mentioned compound 8 succinate and tetrahydrofuran (0.5 L / kg) until the solid is almost dissolved (thick paste). Let the slurry stand at 25°C for 2 weeks until precipitate appears. Dry the solid at 25°C to maintain crystallinity.

[0247] The PXRD pattern of the cocrystal of methyl carbamate {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidin-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate fumarate was determined and shown in [the diagram]. Figure 23 Among them, the peaks observed in the table below were observed.

[0248] Example 5E Preparation of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidine-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate 4-hydroxybenzoic acid cocrystal The eutectic with 4-hydroxybenzoic acid as the eutectic former can be prepared in a manner similar to that of Examples 5A to 5D, using a 1:1 mixture of isopropyl acetate and heptane as the solvent, and obtained using 3 or 4 equivalents of 4-hydroxybenzoic acid.

[0249] Example 5F Preparation of methyl carbamate and 2,5-dihydroxybenzoic acid cocrystal The eutectic formed with 2,5-dihydroxybenzoic acid (gentianic acid) can be prepared in a manner similar to that of Examples 5A to 5D, and obtained by using a 1:1 mixture of isopropyl acetate and heptane as a solvent with 2,5-dihydroxybenzoic acid (gentianic acid).

[0250] Example 6 Preparation of methyl carbamate methoxycyclopentane solvate, namely compound I CPME solvate. A solution of isopropyl acetate of compound 8 prepared above (assuming quantitative conversion, 69.7 mmol, 1.0 equivalent) was combined with N-methylmorpholine (36.7 g, 40 mL, 0.36 mol, 5.2 equivalent) and stirred at 5°C to 10°C. Trifluoroacetic anhydride (38.1 g, 25.5 mL, 0.18 mol, 2.6 equivalent) was added over 30 to 60 minutes, maintaining the reaction temperature above 15°C. The resulting mixture was stirred for 1 hour. The reaction completion of the sample was analyzed (not exceeding 0.5% of compound 8). If the reaction was incomplete, stirring was maintained for another 60 minutes, and additional N-methylmorpholine and trifluoroacetic anhydride were added as necessary (maintaining a 2:1 ratio). The reaction was quenched by adding water containing ammonium hydroxide (28 wt%) (10.7 mL, 76 mmol, 1.1 equivalents) (74.1 mL water, 3.0 L / kg of compound 6 free acid from the previous step) or (84.8 mL 3.5% wt% ammonium hydroxide solution, 3.34 L / kg of compound 6 free acid from the previous step), stirring for 30 minutes, then stopped and each layer was allowed to settle. The aqueous phase was removed and the organic phase was sampled (target: no more than 0.1% of ((S)-1-((2S,4R)-2-(((S)-1-cyano-2-((S)-2-oxopyrrolidone-3-yl)ethyl)carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl)-3,3-dimethyl-1-oxobut-2-yl)(2,2,2-trifluoroacetyl)carbamate). If the target is not achieved, a second alkaline wash is required using the same protocol (1.1 equivalent NH4OH 28 wt% mixed with 74.1 mL water (3.0 L / kg)). The organic phase is washed with water (74.1 mL, 3.0 L / kg from the free acid of compound 6 in the previous step). The organic phase is then concentrated to a volume of 200 mL (8 L / kg from the free acid of compound 6 in the previous step) by vacuum distillation (0.3 bar and (internal temperature approximately 30°C)). Cyclopentyl methyl ether (127 mL, 5.0 L / kg from the free acid of compound 6 in the previous step) is added, and the solution is concentrated to a volume of 200 mL (8 L / kg from the free acid of compound 6 in the previous step) by vacuum distillation. This cyclopentyl methyl ether addition and distillation process is repeated three more times. The water content (Karl Fischer) of the sample is analyzed, with a target of no more than 0.2 wt% water and no more than 1% isopropyl acetate. If the target values ​​are not met, the distillation process is repeated using the same protocol. The resulting solution / slurry was stirred at 40°C for 30 to 60 minutes, cooled to 10°C at a rate of 0.1 K / min, and stirred at 10°C for at least 1 hour.The solid was collected by filtration, washed with 2.5 L / kg and 1 L / kg CPME, and dried in a vacuum oven at 70 °C for 12 hours to obtain 21.1 g of {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate methoxycyclopentane (CPME) solvate.

[0251] Product characterization: Note: The sample is a CPME solvate with an API:CPME molar ratio of approximately 5:2. Due to the N14-C18 and N24-C25 amide bonds, the API contains two minor rotational isomers, accounting for approximately 6.7% and 9.2%, respectively. In relevant cases, the less abundant rotational isomer signal is designated as "minor".

[0252] 1 H NMR (600 MHz, DMSO- d 6, 298K): δ 9.08 (d, J = 7.04 Hz, minor), 9.00 (d, J = 8.59 Hz, 1H), 7.70 (s, minor), 7.64 (s, 1H), 7.24 (d, J = 8.75 Hz, 1H), 6.91 (d, J = 9.08 Hz, minor), 6.83 (br, minor), 4.94 (ddd, J = 10.91, 8.58, 5.02Hz, 1H), 4.89 (q, J = 7.53 Hz, minor), 4.80 (dd, J = 8.37, 2.93 Hz, minor), 4.37 (dd, J = 8.19, 6.19 Hz, 1H), 4.15 (d, J = 8.74 Hz, 1H), 4.07 (br, minor), 4.04 (d, J = 8.99 Hz, minor), 3.96 (m, 2H), 3.86 (br, minor), 3.74 (m, CPME, 1H), 3.66 (d, J = 7.07 Hz, minor), 3.52 (s, 3H), 3.50 (s, minor), 3.40 (m, 1H), 3.27-3.32 (m, overlapping with residual water, minor), 3.12-3.19 (om, minor), 3.15 (s, CPME, 3H), 3.13 (om, 1H), 3.04 (td, J = 9.35, 7.07 Hz, 1H), 2.45 (m, 1H), 2.30 (m, 1H), 2.16 (ddd, J = 13.60, 11.03, 4.47 Hz, 1H), 2.04-2.13 (om, 2H), 1.84 (m, minor), 1.64-1.75 (om, 2H), , 1.51-1.65 (om, CPME, 6H), 1.46 (m, CPME, 2H), 0.94 (s, 9H), 0.89 (s, minor). 13 C NMR (151 MHz, DMSO- d 6, 298K): δ 177.5 (minor), 177.4, 170.8, 170.4 (minor), 169.8, 169.4 (minor), 156.9, 156.3 (minor), 127.1 (1JCF = 277.4 Hz, minor), 126.9 (1JCF = 277.8 Hz), , 119.5, 119.2 (minor), 81.9 (CPME), 58.9, 58.5, 58.4 (minor), 55.5 (CPME), 51.4, 51.3 (minor), 46.7, 45.3 (minor), 41.2 (2JCF = 27.9 Hz), 39.2 (overlapping with solvent), 38.6 (2JCF = 28.2 Hz (minor), 37.7, 37.3 (minor), 36.6, 35.1 (minor), 34.3, 34.1, 33.2 (minor), 31.3 (CPME), 30.4 (minor), 28.1, 27.3 (minor), 26.8, 26.0, 25.9 (minor), 23.0 (CPME). 19 F NMR (376 MHz, DMSO- d 6 , 298K): δ -70.71, -70.99 (minor), -71.12 (minor). om = overlapping multiple peaks, br = wide signal. HRMS: (ESI+) C 21 H 31 The calculated value of O5N5F3 is 490.2272 Da, and the measured value is also 490.2272 Da.

[0253] PXRD was measured and its values ​​are shown in... Figure 2 middle.

[0254] Example 7 Preparation of the solvate of propyl-2-carbamate methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound I IPAc solvate. The isopropyl acetate solution of {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidone-3-yl]propyl-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, i.e., compound 8 (assuming quantitative conversion of 8.2 g of free acid of compound 6, 22.4 mmol, 1.0 equivalent), prepared in step 3, was combined with N-methylmorpholine (11.8 g, 12.8 mL, 0.12 mol, 5.2 equivalent) and stirred at 5°C to 10°C. Trifluoroacetic anhydride (12.2 g, 8.2 mL, 0.06 mol, 2.6 equivalent) was added after 30 to 60 minutes, maintaining the reaction temperature below 15°C. The resulting mixture was stirred for 1 hour. Analyze the reaction completion of the sample (not exceeding 0.5% of compound 8). If the reaction is incomplete, maintain stirring for an additional 60 minutes, and add additional N-methylmorpholine and trifluoroacetic anhydride (maintaining a 2:1 ratio) if necessary. Quench the reaction by adding water containing ammonium hydroxide aqueous solution (28 wt%) (3.4 mL, 24 mmol, 1.1 equivalents) (23.8 mL water, 3.0 L / kg free acid of compound 6 from step 3) or (27.3 mL 3.5% wt% ammonium hydroxide solution, 3.34 L / kg free acid of compound 6 from step 3), maintaining stirring for 30 minutes, then stop and allow each layer to settle. Remove the aqueous phase and sample the organic phase (target: no more than 0.1% of ((S)-1-((2S,4R)-2-(((S)-1-cyano-2-((S)-2-oxopyrrolidine-3-yl)ethyl)carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl)-3,3-dimethyl-1-oxobut-2-yl)(2,2,2-trifluoroacetyl)carbamate). If the target is not achieved, a second alkaline wash is required following the same protocol (1.1 equivalents of NH4OH 28 wt% mixed with 74.1 mL of water (3.0 L / kg)). Wash the organic phase with water (23.7 mL, 3.0 L / kg of free acid from compound 6 in step 3). The organic phase was then concentrated to a volume of 63.4 mL (8 L / kg of compound 6 free acid from step 3) by vacuum distillation (0.3 bar and internal temperature approximately 30°C to 40°C). Isopropyl acetate (63.4 mL, 8 L / kg of compound 6 free acid from step 3) was added, and the solution was concentrated to a volume of 63.4 mL (8 L / kg of compound 6 free acid from step 3) by vacuum distillation. Isopropyl acetate (63.4 mL, 8 L / kg of compound 6 free acid from step 3) was added, and the solution was concentrated to a volume of 63.4 mL (8 L / kg of compound 6 free acid from step 3) by vacuum distillation.The water content (Karl Fischer) of the sample was analyzed, with a target of no more than 0.2 wt% water. If the water content did not meet the target, the distillation process was continued using the same protocol until the target was met. This solution was stirred at 55 °C (internal temperature) and n-heptane (29.3 mL, 3.7 L / kg from the free acid of compound 6 in step 3) was added over 30 minutes. Methyl carbamate IPAc solvate seed crystals (0.21 g, 0.42 mmol, 2.5 wt% from the free acid of compound 6 in step 3) were added. If the seed crystals dissolve, add more heptane (0.37 L / kg from the free acid of compound 6 in step 3) and add the seed crystals again. Maintain the internal temperature at 50°C to 55°C for 60 minutes. Add n-heptane (69 mL, 8.7 L / kg from the free acid of compound 6 in step 3) at 55°C (internal temperature) for 8 hours. Stir this slurry at 55°C for at least 30 minutes, cool it to 10°C over 5 hours, and stir it at 10°C for at least 2 hours. The solid was collected by filtration, washed twice at 10°C with a pre-cooled mixture of n-heptane (1.2 L / Kg from the free acid of compound 6 in step 3) and isopropyl acetate (0.8 L / Kg from the free acid of compound 6 in step 3), and dried in a vacuum oven at 50°C for 12 hours to give 7.58 g of methyl carbamate isopropyl acetate (IPAc) solvate.

[0255] Product characterization: Note: Due to the N14-C18 and N24-C25 amide bonds, the sample contains two minor rotational isomers, accounting for approximately 8% and 14% of the sample, respectively. Isopropyl acetate (IPAc) is present as a solvate in a ratio of approximately 1.1:2 relative to the API. In relevant cases, the less abundant rotational isomer signal is designated as "minor".

[0256] 1 H NMR (600 MHz, DMSO- d 6, 298K): δ 9.09 (d, J= 7.00 Hz, minor), 9.02 (d, J= 8.59 Hz, 1H), 7.72 (s, minor), 7.66 (s, 1H), 7.27 (d, J= 8.67 Hz, 1H), 6.94 (d, J= 9.07 Hz, minor), 6.85 (br, minor), 4.95 (ddd, J= 10.99, 8.57, 4.98 Hz, 1H), 4.86 (m, IPAc, 1H), 4.80 (dd, J= 8.58, 3.10 Hz, minor), 4.36 (t, J= 7.29Hz, 1H), 4.15 (d, J= 8.74 Hz, 1H), 4.07 (br, minor), 4.04 (d, J= 9.12 Hz, minor), 3.96 (m, 2H), 3.86 (br, minor), 3.66 (d, J= 7.13 Hz, minor), 3.52 (s, 3H), 3.50 (s, minor), 3.41 (m, 1H), 3.30 (m, minor), 3.17 (m, minor), 3.13 (t, J= 9.09 Hz, 1H), 3.04 (td, J= 9.15, 7.04 Hz, 1H), 2.45 (m, 1H), 2.34 (m, minor), 2.30 (m, 1H), 2.24 (m, minor), 2.16 (ddd, J= 13.59, 11.05, 4.44 Hz (1H), 2.06–2.12 (om, 2H), 1.96 (s, IPAc, 3H), 1.84 (m, minor), 1.65–1.73 (om, 2H), 1.17 (d, J = 6.22Hz, IPAc, 6H), 0.94 (s, 9H), 0.89 (s, minor). 13 C NMR (151 MHz, DMSO- d 6, 298K): δ177.5 (minor), 177.4, 170.8, 170.4 (minor), 169.8, 169.7 (IPAc), 169.4 (minor), 156.9, 156.3 (minor), 127.2 (1JCF = 276.9 Hz, minor), 127.0 (1JCF = 278.6 Hz), 119.5, 119.2 (minor), 66.9 (IPAc), 58.9, 58.5, 58.4 (minor), 51.4, 51.3 (minor), 46.7, 45.3 (minor), 41.2 (2JCF = 28.14 Hz), 40.0 (minor), 39.6 (minor, ov), 39.1 (ov), 38.7 (2JCF = 28.71 Hz, minor), 37.6, 37.3 (minor), 36.5, 35.1 (minor), 34.3, 34.1, 33.2 (minor), 30.4 (minor), 28.3 (minor), 28.1, 27.3 (minor), 26.8, 26.0, 25.9 (minor), 21.5 (IPAc), 21.0. 19 F NMR (376 MHz, DMSO- d 6 (298K): δ -70.71, -70.99 (minor), -71.12 (minor). om = overlapping multiplets, ov = overlap with solvent, br = broad signal. HRMS: (ESI) m / z [M+H] + C 21 H 31 The calculated value of O5N5F3 is 490.2272 Da, and the measured value is 490.2276 Da. PXRD was determined, and the data provided are from... Figure 3 middle.

[0257] Example 8 Preparation of methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, anhydrous, polymorph 1 Methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate (200 g, in CPME or IPAc solvate form) was combined with heptane (2000 mL) and stirred at 20 °C. The mixture was then heated to 70 °C and stirred at 70 °C for at least 6 hours. The mixture was then cooled to 50 °C and sampled to confirm conversion to form 1 polymorph. If the form was not form 1, the mixture was heated back to 70 °C for 6 hours and the sampling was repeated. If the form was form 1, the mixture was cooled to 20 °C over a 4-hour period and then held at 20 °C for at least 2 hours. The slurry was filtered and washed with heptane (400 mL). The wet filter cake was then dried overnight at 70 °C, and the methyl carbamate form {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidine-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate 1 was isolated (96% yield).

[0258] Product characterization: Note: Due to the N1-C10 and N16-C17 amide bonds, the sample contains two minor rotational isomers, accounting for approximately 6% and 10% of the sample, respectively. In relevant cases, the less abundant rotational isomer signal is designated as "minor".

[0259] 1 H NMR (600 MHz, DMSO- d 6, 298K): δ 9.11(d, J=6.97 Hz, minor), 9.05 (d, J=8.63 Hz, 1H), 7.75 (s, minor), 7.69 (s, 1H), 7.32 (d, J=8.66 Hz, 1H), 7.01 (d, J=9.16 Hz, minor), 6.90 (br, minor), 4.95 (ddd, J=11.23, 8.63, 4.86 Hz, 1H), 4.88(q, J=7.53 Hz, minor), 4.80 (dd, J=8.16, 2.90 Hz, minor), 4.35 (t, J=7.53 Hz, 1H), 4.14 (d, J=8.78 Hz, 1H), 4.07 (br, minor), 4.04 (d, J=9.10 Hz, minor), 3.98-3.95 (m, 1H), 3.84 (br, minor), 3.65 (d, J=7.06 Hz, minor), 3.52 (s, 3H), 3.49 (s, minor), 3.41 (m, 1H), 3.31 (m, minor), 3.17 (m, minor), 3.13 (t, J=9.11 Hz, 1H), 3.03 (td, J=9.32, 7.17 Hz, 1H), 2.46 (m, 1H), 2.30 (m, 1H), 2.24 (m, minor), 2.16 (ddd, J=13.51, 11.25, 4.28 Hz, 1H), 2.12–2.05 (om, 2H), 1.84 (m, minor), 1.73–1.65 (om, 2H), 0.94 (s, 9H), 0.89 (s, minor). 13 C NMR (151 MHz, DMSO- d 6, 298K): δ 177.5 (minor), 177.4, 170.8, 170.4 (minor), 169.9 (minor), 169.7, 169.3 (minor), 156.9, 156.3 (minor), 155.5 (minor), 127.0 (1JCF = 278.4 Hz), 119.5, 119.2 (minor), 59.4 (minor), 58.9, 58.8 (minor), 58.6 (minor), 58.5, 58.3 (minor), 51.6 (minor), 51.4, 51.3 (minor), 46.8 (minor), 46.7, 45.3 (minor), 41.1 (2JCF = 28.0 Hz). Hz), 39.5 (minor, ov), 39.1, 39.0 (minor, ov), 38.6 (2JCF = 27.8 Hz, minor), 37.6, 37.3 (minor), 36.5, 35.1 (minor), 34.3, 34.2 (minor), 34.1, 33.2 (minor), 30.3 (minor), 28.1, 27.3 (minor), 26.7, 26.0, 25.9 (minor). 19 F NMR (376MHz, DMSO- d 6 (298K): δ -70.17, -70.45 (minor), -70.58 (minor). om = overlapping multiplets, ov = overlap with solvent, br = broad signal. HRMS: (ESI) m / z [M+H] + C 21 H 31 The calculated value of O5N5F3 is 490.2272 Da, and the measured value is 490.2271 Da.

[0260] Example 9 Methyl carbamate {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidone-1-yl]-3,3-dimethyl-1-oxobut-2-yl}carbamate, anhydrous, polymorph 1, was prepared from compound I CPME solvate. The solvate of compound I CPME (30.09 g, 51.03 mmol, 100 wt%) and heptane (300 mL, 2047.9 mmol, 100 wt%) were added to a 1000 mL two-piece OptiMax reactor equipped with a top stirrer and baffles at 350 rpm. The mixture was stirred at 20 °C and heated to 70 °C. The mixture was stirred at 70 °C for 12 hours, then cooled to 25 °C over 5 hours and stirred overnight. The resulting slurry was filtered and washed with heptane (60 mL, 409.58 mmol, 100 wt%). The solid was dried overnight under vacuum at 50 °C to obtain the anhydrous free form of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1.

[0261] The PXRD of N-(methoxycarbonyl)-3-methyl-L-valinel-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1 was determined, and the PXRD spectrum is provided in [the original text is missing]. Figure 1 The peak values ​​are provided in the table below.

[0262] Table: List of PXRD peaks and relative intensities for N-(methoxycarbonyl)-3-methyl-L-valinel-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1. PXRD peaks are in °2 Å, ±0.2 Å per peak.

[0263] Single-crystal X-ray diffraction (SXRD) of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1 was determined, and the data are provided in the table below.

[0264] Table: Crystal structure data for N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1.

[0265] Determination of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1 13 C solid-state NMR.

[0266] Table: N-(methoxycarbonyl)-3-methyl-L-valinel-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1 13 List of C solid-state NMR peaks. Each peak is ±0.2 ppm.

[0267] Determination of N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidone-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1 19 F solid-state NMR.

[0268] Table: N-(methoxycarbonyl)-3-methyl-L-valinel-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1 19 F solid-state NMR peak list.

[0269] Table: Examples of characterization identifiers for N-(methoxycarbonyl)-3-methyl-L-valine-(4R)-N-{(1S)-1-cyano-2-[(3S)-2-oxopyrrolidine-3-yl]ethyl}-4-(trifluoromethyl)-L-prolineamide form 1 using a single method or a combination of instrumental methods.

Claims

1. The preparation of (2S,4R)-1-{(2S)-2-[(methyloxycarbonyl)amino]-3,3- dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid M + a method of preparing a salt (compound 6a), ， The method comprises the steps of: a) combining (2R,4R)-tert-butyl 1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3- dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate (Compound 4), a solvent and water; and b) adding a base comprising M + to the mixture from step a) to generate in situ the intermediate (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid tert-butyl ester, i.e. compound 5, which is further reacted to give (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutyryl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid M + salt, i.e. compound 6a ； wherein M + is selected from Li + , Na + , and K + .

2. The process of claim 1, wherein the M + alkoxide is selected from sodium tert-butoxide, sodium tert-amylate, potassium methoxide, potassium hydroxide, potassium tert-butoxide, potassium tert-amylate, and potassium hexamethyldisilazide, and the solvent is selected from methyl tert-butyl ether, tetrahydrofuran, isopropyl alcohol, tert-amyl alcohol, acetonitrile, tert-butyl alcohol, and 2-methyltetrahydrofuran.

3. The method according to claim 1 for the preparation of potassium (2S,4R)-1-{(2S)-2- [(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2- carboxylate, Compound 6 ， The method comprises the steps of: a) combining (2R,4R)-tert-butyl 1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3- dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate, Compound 4, a solvent and water; and b) adding a base comprising K to the mixture from step a) to generate in situ the intermediate tert-butyl (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylate, i.e. compound 5, which is further reacted to potassium (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylate, i.e. compound 6 + b) adding a base comprising K to the mixture from step a) to generate in situ the intermediate tert-butyl (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylate, i.e. compound 5, which is further reacted to potassium (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylate, i.e. compound 6 。 4. The method of claim 3, wherein the K + containing base is selected from the group consisting of potassium tert-butoxide, potassium tert-pentoxide, potassium methoxide, potassium hydroxide, and potassium hexamethyldisilylamide, and the solvent is selected from the group consisting of methyl tert-butyl ether, tetrahydrofuran, isopropyl alcohol, tert-pentanol, acetonitrile, tert-butanol, and 2-methyltetrahydrofuran.

5. The method of claim 4, wherein the K + containing base is potassium tert-butoxide.

6. The method according to claim 5, wherein in step a) 1.0 equivalent of (2R,4R)- tert-butyl 1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylate, Compound 4, is combined with 2.5 volumes of solvent methyl tert-butyl ether (MTBE) and 1.2 equivalents of water at ambient temperature and in step b) 1.2 equivalents of potassium tert-butoxide (20 wt% in THF) is added at ambient temperature.

7. The method according to claim 6, further comprising steps c) to g), wherein step c) stirring the reaction mixture obtained from step b) for a period of at least 12 hours at ambient temperature; step d) adding 0.5 volumes of methanol to the reaction mixture obtained from step c) under stirring to obtain a reaction mixture slurry; step e) filtering the reaction mixture slurry obtained from step d) to isolate a solid comprising potassium (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3- dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate, Compound 6; step f) washing the solid comprising potassium (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate, Compound 6, obtained from step e) with a mixture of MTBE (1.7 volumes) and methanol (0.3 volumes); and step g) drying the solid comprising potassium (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate, Compound 6, obtained in step f).

8. The method according to claim 7, wherein the isolated solid comprises greater than or equal to 95 wt% crystalline potassium (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3- dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2-carboxylate, Compound 6.

9. The process of claim 8, wherein the isolated solid comprises less than 5% by weight of (2R,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylate potassium salt.

10. A process for preparing a solvate of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1- cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1- yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate (Compound I) ； The process comprises the following steps: h) reacting (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylic acid, i.e. Compound 6', or a pharmaceutically acceptable salt thereof, with (2S)-2-amino-3-[(3S)-2-oxopyrrolidin-3-yl]propanamide, i.e. Compound 7', or a pharmaceutically acceptable salt thereof, in the presence of a peptide coupling reagent, a base and a solvent, ， to give methyl {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidin-3- yl]propan-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate, i.e. Compound 8; and i) reacting Compound 8 with a dehydrating agent ， to give a solvate of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate, i.e. a solvate of Compound I.

11. The process of claim 10, wherein in step h) the peptide coupling reagent is selected from the group consisting of 2-chloro-1-methylpyridinium p-toluenesulfonate, a combination of 2-hydroxypyridine N-oxide with 1-ethyl-3-(3- dimethylaminopropyl)carbodiimide, and a combination of 2-hydroxypyridine N-oxide with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and the base is triethylamine, N-methylmorpholine or N,N-diisopropylethylamine.

12. The process of claim 11, wherein the solvent in step h) is methyl ethyl ketone or isopropyl acetate.

13. The process of claim 12, wherein in step i) the dehydrating agent is selected from the group consisting of trifluoroacetic anhydride, propanephosphonic anhydride, triphenyl phosphite, diethyl chlorophosphate, ethyl dichlorophosphate, phosphorus trichloride and tris(dimethylamino)phosphine in the presence of a base selected from the group consisting of N-methylimidazole, N-methylmorpholine, diethylamine, triethylamine and 1,8-diazabicyclo(5.4.0)undec-7-ene.

14. The process of claim 13, wherein in step i) the dehydrating agent is trifluoroacetic anhydride or propanephosphonic anhydride.

15. The process of claim 14, wherein isopropyl acetate is used as the solvent in steps h) and i), and the reaction mixture from step i) is concentrated and heptane is added thereto to give a methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate isopropyl acetate solvate, i.e. Compound I IPac solvate.

16. The process of claim 13, wherein in step h) the solvent is methyl ethyl ketone, the peptide coupling reagent is a combination of 2-hydroxypyridine N-oxide and 1-ethyl-3-(3- dimethylaminopropyl)carbodiimide, and the base is triethylamine.

17. The process of claim 16, wherein after completion of the coupling reaction, the solvent of the reaction mixture from step h) is exchanged into isopropyl acetate by adding isopropyl acetate and distillation, and in step i) the dehydrating agent is trifluoroacetic anhydride and the base is N-methylmorpholine.

18. The process of claim 17, wherein the reaction mixture from step i) is quenched with aqueous ammonium hydroxide, the layers are separated, and the solvent of the isopropyl acetate layer is exchanged into cyclopentyl methyl ether by adding cyclopentyl methyl ether and distillation.

19. The process of claim 18, wherein the cyclopentyl methyl ether mixture from step i) is cooled to 10 °C and stirred at 10 °C for one hour or more, and a methyl {(2S)-1-[(2S,4R)-2-({(1S)-1- cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3- dimethyl-1-oxobutan-2-yl}carbamate cyclopentyl methyl ether solvate, i.e. Compound I CPME solvate, is isolated.

20. A method of preparing Form 1 polymorph of methyl {(2S)-l-[(2S,4R)-2-({(lS)-l- cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin- 1 -yl] -3, 3 -dimethyl- 1 -oxobutan-2-yl} aminoformate, Compound I, comprising the steps of: The methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4- (trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate ethyl acetate solvate, isopropyl acetate solvate, or methoxycyclopentane solvate is combined with heptane, and the mixture is heated to a temperature range of 50 °C to 100 °C, and the mixture is stirred to give methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4- (trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate, i.e. Compound I Form 1.

21. The method of claim 20, wherein the mixture is stirred at 60 °C to 80 °C for a period of 6 hours to 24 hours.

22. The method of claim 21, wherein the mixture is stirred at about 70 °C for 6 hours to 12 hours, followed by cooling the mixture to 20 °C over 4 hours and holding at 20 °C for 2 hours, followed by isolating methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4- (trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate, Form 1 of Compound I.

23. A method of preparing an ethyl acetate solvate of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4- (trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate (Compound I, ethyl acetate solvate) ； the method comprising the steps of: h') reacting (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylate, Compound 6, with (2S)-2-amino-3-[(3S)-2- oxopyrrolidin-3-yl]propanamide hydrochloride (1:1), Compound 7, in the presence of 2-chloro-1-methylpyridinium p-toluenesulfonate and a base ， to give methyl {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2-oxopyrrolidin-3-yl]propan-2- yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate, Compound 8; and i') reacting Compound 8 with trifluoroacetic anhydride in the presence of N-methylimidazole in ethyl acetate ， to give an ethyl acetate solvate of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate, the EtOAc solvate of Compound I.

24. The method of claim 23, wherein step h') is performed in methyl ethyl ketone and water.

25. The process of claim 24, wherein 1.0 equivalent of potassium (2S,4R)-1-{(2S)-2- [(methoxycarbonyl)amino]-3,3-dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2- carboxylate, Compound 6, is reacted with 1.15 equivalents of (2S)-2-amino-3-[(3S)-2- oxopyrrolidin-3-yl]propanamide hydrochloride (1 : 1), Compound 7, in the presence of 1.2 equivalents of 2-chloro-1-methylpyridinium p-toluenesulfonate, and the base is 3.0 equivalents of N-methylmorpholine.

26. The process of claim 38, wherein the reaction mixture in step h') is stirred at 20 °C for 4 hours; the solvent from the crude reaction mixture from step h') is exchanged into ethyl acetate by vacuum distillation until the water content is less than 0.2% by weight to give a slurry of methyl {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2- oxopyrrolidin-3-yl]propan-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3- dimethyl-1-oxobutan-2-yl}carbamate, Compound 8, in ethyl acetate; and in step i'), the slurry of methyl {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2- oxopyrrolidin-3-yl]propan-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3- dimethyl-1-oxobutan-2-yl}carbamate, Compound 8, in ethyl acetate is cooled to 0 °C and 5.0 equivalents of N-methylimidazole is added, followed by the addition of 2.5 equivalents of trifluoroacetic anhydride over 30 minutes, and the reaction mixture is stirred at 0 °C for 1 hour.

27. The process of claim 26, further comprising step j) quenching the reaction mixture from step i') with an aqueous mixture of citric acid monohydrate and sodium chloride, and separating the resulting layers, and back-extracting the aqueous layer with ethyl acetate, and vacuum concentrating the combined organic ethyl acetate layers to approximately half the original volume, adding heptane, followed by isolating methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate as an ethyl acetate solvate by filtration.

28. The method of claim 27, further comprising the step of: The ethyl acetate solvate of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate is combined with heptane and the mixture is stirred at 60 °C to 80 °C for a period of 6 hours to 24 hours to obtain methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2- [(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl- 1-oxobutan-2-yl}carbamate, Form 1 of Compound I.

29. The process of claim 28, wherein the mixture is stirred at about 70 °C for 6 hours to 12 hours, followed by cooling the mixture to 20 °C over 4 hours and holding at 20 °C for 2 hours, followed by isolating the methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate, Form 1 of Compound I.

30. A process for preparing a mixture of Form 1 of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1- cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3- dimethyl-1-oxobutan-2-yl}carbamate and microcrystalline cellulose (MCC) or microcrystalline cellulose-SiO2 (MCC-SiO2), the process comprising steps (k) to (q): (k) dissolving Form 1 of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate in ethyl acetate and heptane; (l) seeding the solution obtained in step (k) with about 10% to about 50% by weight of microcrystalline cellulose or microcrystalline cellulose-SiO2, wherein the % by weight is the % by weight of the microcrystalline cellulose or microcrystalline cellulose-SiO2 relative to the total weight of the microcrystalline cellulose or microcrystalline cellulose-SiO2 and Form 1 of Compound I; (m) adding heptane to the mixture from step (l); (n) removing the ethyl acetate present in the mixture from step (m) by constant volume distillation and replacing with heptane until the ethyl acetate content is less than 4% by weight of the total solvent composition to obtain a slurry; (o) stirring the slurry from step (n) at 70 °C or higher for at least 6 hours and then cooling to ambient temperature; (p) isolating Form 1 of the resulting methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate from the mixture with microcrystalline cellulose or microcrystalline-Si02; and (q) drying the product from step (p).

31. The process of claim 30, wherein: (k) dissolving Form 1 of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate in ethyl acetate (6 L / Kg Form 1) and heptane (2 L / kg Form 1) at 60 °C; (l) cooling the solution to 45 °C and seeding with 10 wt% microcrystalline cellulose; (m) adding heptane to the mixture from step (l) over a period of 4 hours, wherein the amount of heptane added is about 7 L heptane / Kg Form 1, and cooling the mixture to 20 °C over no less than 3 hours; (n) removing ethyl acetate from the mixture from step (c) by constant volume distillation (15 L solvent / Kg Form 1) and replacing with heptane until the ethyl acetate content is less than 4 wt% of the total solvent composition to obtain a slurry; (o) stirring the slurry from step (n) at 80 °C for at least 6 hours, and then cooling to 20 °C over 5 hours; (p) isolating Form 1 of the resulting methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate from the mixture with microcrystalline cellulose (90 wt% / 10 wt%); and (q) drying the solid mixture from step (p) at 80 °C for at least 12 hours.

32. The process of claim 31, wherein the solid mixture obtained from step (g) comprises Form 1 of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3- yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate having a D[90] value of 95 μm to 240 μm and a D[50] value of 30 μm to 85 μm.

33. The compound (2S,4R)-1-{(2S)-2-[(methyloxy carbonyl)amino]-3,3-dimethylbutanoyl}-4- (trifluoromethyl)pyrrolidine-2-carboxylic acid; or a salt thereof.

34. The compound of claim 33, wherein the salt is selected from lithium, sodium, and potassium.

35. The compound of claim 34, which is (2S,4R)-1-{(2S)-2-[(methoxycarbonyl)amino]-3,3- dimethylbutanoyl}-4-(trifluoromethyl)pyrrolidine-2-carboxylic acid potassium.

36. A composition comprising 90% by weight of methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2- oxopyrrolidin-3-yl]ethyl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate Form 1 and 10% by weight of microcrystalline cellulose, wherein the methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4- (trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate Form 1 has a D[90] value of 95 pm to 240 pm and a D[50] value of 30 pm to 85 pm.

37. The composition of claim 36, wherein the particle size distribution of the methyl {(2S)-1-[(2S,4R)-2-({(1S)-1-cyano-2-[(3S)-2-oxopyrrolidin-3-yl]ethyl}carbamoyl)-4- (trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl}carbamate Form 1 is unimodal.

38. A co-crystal comprising methyl {(2S)-1-[(2S,4R)-2-({(2S)-1-amino-1-oxo-3-[(3S)-2- oxopyrrolidin-3-yl]propan-2-yl}carbamoyl)-4-(trifluoromethyl)pyrrolidin-1-yl]-3,3-dimethyl-1- oxobutan-2-yl}carbamate and an organic carboxylic acid selected from tartaric acid, maleic acid, succinic acid, fumaric acid, 4-hydroxybenzoic acid, and 2,5-dihydroxybenzoic acid.

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