SULFATE CRYSTALS OF MELANOCORTIN RECEPTOR AGONIST COMPOUND AND METHOD OF PRODUCING SAME

The present invention relates to a sulfate crystal form of a compound represented by formula 1, a method of producing same, and a pharmaceutical composition comprising same. The sulfate crystal form of the compound represented by formula 1 of the present invention may be characterized by an XRPD pattern, a DSC profile, and/or a TGA profile.

Technical Field

The present invention relates to a crystalline form of a novel compound exhibiting an excellent agonistic activity for a melanocortin receptor, a method for preparing the same, and a pharmaceutical composition comprising the same.

BACKGROUND

Leptin protein is a hormone secreted by adipocytes, and its secretion amount increases with an increase in body fat content. It regulates functions of various neuropeptides produced from hypothalamus, thereby regulating various in vivo functions, including appetite, body fat content, and energy metabolism (Schwartz, et al., Nature 404, 661-671 (2000)). The leptin protein signal transduction for controlling appetite and body weight is made through the regulation of many factors downstream, the most representative of which are melanocortin, agouti-related peptide (AgRP), and neuropeptide Y (NPY) hormones.

When the concentration of leptin in the blood increases as a result of excess calories in vivo, the secretion of proopiomelanocortin (POMC) protein hormone from the pituitary gland increases and the production of AgRP and NPY decreases. A small peptide hormone, alpha-melanocyte-stimulating hormone (MSH), is produced from POMC neurons. The hormone is an agonist for melanocortin-4 receptors (MC4R) of second-order neurons and ultimately induces appetite decrease. Meanwhile, when the concentration of leptin decreases as a result of calorie deficiency, the expression of AgRP, an MC4R antagonist, increases, and the expression of NPY also increases, which ultimately promotes appetite. That is, according to the change of leptin, the alpha-MSH hormone and the AgRP hormone act as agonists and antagonists for MC4R and thus are involved in appetite control.

The Alpha-MSH hormone binds to three MCR subtypes in addition to MC4R to induce various physiological reactions. Five MCR subtypes have been identified so far. Among them, MC1 R is expressed mainly in skin cells and is involved in regulating melanin pigmentation (skin pigmentation). MC2R is expressed mainly in the adrenal gland and is known to be involved in the production of glucocorticoid hormones. Its ligand is only adrenocorticotropic hormone (ACTH) derived from POMC. MC3R and MC4R, which are expressed mainly in the central nervous system, are involved in regulating appetite, energy metabolism, and body fat storage efficiency, and MC5R expressed in various tissues is known to regulate exocrine function (Wikberg, et al., Pharm Res 42 (5) 393-420 (2000)). In particular, activation of the MC4R receptor induce appetite decrease and energy metabolism increase and thus has an effect of efficiently reducing body weight. Therefore, it has been proven to be a major action point in the development of anti-obesity drugs (Review: Wikberg, Eur. J. Pharmacol 375, 295-310 (1999)); Wikberg, et al., Pharm Res 42 (5) 393-420 (2000); Douglas et al., Eur J Pharm 450, 93-109 (2002); O'Rahilly et al., Nature Med 10, 351-352 (2004)).

The role of MC4R in the control of appetite and body weight was primarily demonstrated through an experiment in an animal model of abnormal expression of the agouti protein (agouti mouse). In the case of the Agouti mouse, it was found that due to genetic mutation, the agouti protein was expressed at a high concentration in the central nervous system and acted as an antagonist of MC4R in the hypothalamus to cause obesity (Yen, T T et al., FASEB J. 8, 479-488 (1994); Lu D., et al. Nature 371, 799-802 (1994)). Subsequent research results showed that the agouti-related peptides (AgRP) similar to the actual agouti protein were expressed in hypothalamic nerves, and these are also known to be antagonists for MC4R and be involved in controlling appetite (Shutter, et al., Genes Dev., 11, 593-602 (1997); Ollman, et al. Science 278, 135-138 (1997)).

Intracerebral administration of alpha-MSH, which is an in vivo MC4R agonist, to animals leads to the effect of reducing appetite. When treating the animals with SHU9119 (peptide) or HS014 (peptide), which are MC4R antagonists, it was observed that appetite increased again (Kask et al., Biochem. Biophys. Res. Comm. 245, 90-93 (1998)). In addition, in animal studies using Melanotan II (MTII, Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH2) and the similar agonist thereof, HP228, after intracerebral, intraperitoneal, or subcutaneous administration, efficiencies of inhibiting appetite, reducing body weight, increasing energy metabolism, etc. were found. (Thiele T. E., et al. Am J Physiol 274 (1 Pt 2), R248-54 (1998); Lee M. D., et al. FASEB J 12, A552 (1998); Murphy B., et al. J Appl Physiol 89, 273-82 (2000)). On the contrary, administration of the representative SHU9119 to animals showed significant and sustained feed intake and weight gain, providing pharmacological evidence that MCR agonists could be anti-obesity agents. The effect of reducing appetite, which is clearly exhibited upon administration of MTII, was not observed in MC4R knock-out (KO) mice. This experimental result proves again that the appetite-reducing effect is achieved mainly through the activation of MC4R (Marsh, et al., Nat Genet 21, 119-122 (1999)).

Anorectic agents acting on the central nervous system were the main types of anti-obesity drugs developed so far. Among them, most were drugs that modulate the action of neurotransmitters. Examples include noradrenalin agents (phentermine and mazindol), serotonergic agents, fluoxetine and sibutramine, and the like. However, the neurotransmitter modulators have a wide range of effects on various physiological actions in addition to appetite suppression, through numerous subtype receptors. Accordingly, the modulators lack selectivity for each subtype, and thus have a major disadvantage in that they are accompanied by various side effects when administered for a long period.

Meanwhile, melanocortin receptor agonists are neuropeptides, not neurotransmitters. Given that in MC4R gene KO mice, all functions other than energy metabolism are normal, they have an advantage as an action point in that they can induce only weight loss through appetite suppression without affecting other physiological functions. In particular, the receptor is a G-protein coupled receptor (GPCR) that belongs to the most successful category of new drug action points developed so far. Thus, the action point greatly differ from existing action points in that it is relatively easy to secure selectivity for subtype receptors.

As an example of utilizing a melanocortin receptor as an action point, international publication nos. WO 2008/007930 and WO 2010/056022 disclose compounds as agonists of the melanocortin receptor.

In addition, the inventors of the present invention have conducted extensive studies and invented a novel compound of the following formula 1 having an excellent agonistic activity selective for a melanocortin receptor, in particular, melanocortin-4 receptor (MC4R), and a method for preparing the same (application no. KR 10-2019-0141649 (filed on 7 Nov. 2019)):

wherein R1 is a C2-C5 alkyl.

Meanwhile, the crystal structure of a pharmaceutically active ingredient often affects the chemical stability of the drug. Different crystallization conditions and storage conditions can lead to changes in the crystal structure of the compound, and sometimes the accompanying production of other forms of the crystalline form. In general, an amorphous drug product does not have a regular crystal structure, and often has other defects such as poor product stability, smaller particle size, difficult filtration, easy agglomeration, and poor flowability. Thus, it is necessary to improve various physical properties of the product. However, in general, a person skilled in the art could not easily predict under what conditions a compound will crystallize effectively and which crystalline form will be advantageous in terms of reproducibility, stability, and bioavailability, and thus there is a need to study different types of various crystal structures for a single compound.

DETAILED DESCRIPTION

Technical Problem

An aspect of the present invention provides a stable crystalline form of a novel compound having an excellent agonistic activity, which is selective for a melanocortin receptor, in particular, melanocortin-4 receptor (MC4R), and a method for preparing the same.

Another aspect of the present invention provides a pharmaceutical composition comprising the stable crystalline form of the novel compound.

Technical Solution

According to an aspect of the present invention, there is provided a crystalline form of sulfate of a compound of the following formula 1, wherein the X-ray powder diffraction (XRPD) pattern has characteristic peaks with the diffraction angles (28 values) described in i) or ii):

Since the compound of formula 1 can have an asymmetric carbon center and an asymmetric axis or an asymmetric plane, it can exist as cis or trans isomers, R or S isomers, racemates, diastereomer mixtures, and individual diastereomers, all of which are within the scope of the compound of formula 1.

In the present specification, unless otherwise specified for convenience, the compound of formula 1 is used to include all of the compound of formula 1, an isomer thereof, and a solvate thereof.

In one embodiment, according to the present invention, in formula 1, R1is a C2to C5alkyl. In another embodiment, according to the present invention, in formula 1, R1is a straight-chain or branched C2to C5alkyl, for example, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, or tert-butyl.

In another embodiment, according to the present invention, in formula 1, R1is a C2to C4alkyl. In another embodiment, according to the present invention, in formula 1, R1is a straight-chain or branched C2to C4alkyl, for example, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl. Specifically, R1may be iso-propyl.

In one embodiment, according to the present invention, the crystalline form of sulfate of the compound of formula 1 may be crystalline form A of sulfate of the compound of formula 1 having 5 or more, 7 or more, 9 or more, 10 or more, 13 or more, 15 or more, 17 or more, or 20 or more characteristic peaks selected from among 3.27+0.2°, 5.73±0.2°, 6.62+0.2°, 9.58±0.2°, 10.68±0.2°, 14.52+0.2°, 17.11±0.20, 17.73±0.2°, 18.08+0.2°, 18.37±0.2°, 18.61±0.20, 18.96±0.2°, 19.28+0.2°, 19.58±0.2°, 19.85±0.2°, 20.13+0.2°, 20.69±0.2°, 21.38±0.2°, 21.94±0.2°, and 22.53±0.2° in the X-ray powder diffraction pattern.

In one embodiment, according to the present invention, the crystalline form A may have the X-ray powder diffraction (XRPD) pattern substantially similar toFIG.1.

In the crystalline form A, in one embodiment, according to the present invention, the compound of formula 1 may be a solvate, for example, a solvate with acetate. Accordingly, the crystalline form A of the sulfate may be that of a solvate of the compound of formula 1. This may be confirmed by the observation of a change in the XRPD pattern after drying the crystalline form A.

In one embodiment, according to the present invention, the compound of formula 1 may be a solvate with acetate. Herein, in the solvate with acetate, ‘acetate’ may include, but is not limited to, for example, at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, n-butyl acetate, t-butyl acetate, and isobutyl acetate.

In one embodiment, according to the present invention, the compound of formula 1 may be a solvate with isobutyl acetate (iBuOAc).

In another embodiment, according to the present invention, the crystalline form of sulfate of the compound of formula 1 may be crystalline form B of sulfate of the compound of formula 1 having 5 or more, 7 or more, 9 or more, 10 or more, 13 or more, 15 or more, 17 or more, or 20 or more characteristic peaks selected from among 3.42±0.2°, 6.05±0.2°, 6.69+0.2°, 7.01±0.20, 9.29±0.2°, 9.67+0.2°, 10.07±0.2°, 10.40±0.2°, 12.69+0.2°, 15.31±0.20, 16.40±0.2°, 18.15±0.2°, 18.56+0.2°, 19.50±0.2°, 19.64±0.2°, 19.93+0.2°, 20.13±0.2°, 20.33+0.2°, 20.88±0.2°, and 28.15±0.2° in the X-ray powder diffraction pattern.

In another embodiment, according to the present invention, the crystalline form B may have the X-ray powder diffraction (XRPD) pattern substantially similar toFIG.2.

In another embodiment, according to the present invention, the crystalline form B, in the thermogravimetric analysis (TGA) profile, may have 15% or less, 10% or less, 9% or less, or 8.9% of a weight loss in a temperature range of about 40° C. to 150° C., and/or may be decomposed beyond about 248° C.

In another embodiment, according to the present invention, the crystalline form B, in the differential scanning calorimetry (DSC) profile, may have an endothermic peak at about 100° C. to 150° C., which is within a temperature range at which a weight loss occurs in the TGA profile. In addition, the crystalline form B may have an exothermic peak at about 145° C.

In another embodiment, according to the present invention, the crystalline form B may have the TGA (top) and/or DSC (bottom) profiles substantially similar toFIG.3.

In another embodiment, according to the present invention, the crystalline form B may be melted at about 137° C.˜160° C., specifically, 137.7° C. to 155.1° C., as determined by hot stage microscopy (HSM).

In another embodiment, according to the present invention, the crystalline form B may have the HSM photographs substantially similar toFIGS.4to6.

In another embodiment, according to the present invention, the crystalline form B may have a solubility of more than 56 mg/mL in an aqueous solution.

In the present specification,

X-ray powder diffraction (XRPD) analysis shows the results obtained with PANalytical X′ Pert Pro MPD system (Malvern Panalytical Ltd.).

Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis show the results obtained with TGA/DSC 3 (Mettler-Toledo AG).

Hot stage microscopy (HSM) shows the results obtained with Leica DM LP microscope using Linkman hot stage (model FTIR 600) with TMS 93 controller.

Solubility indicates the result of measurement based on the final volume of water added to a sample when it is visually confirmed that the sample is completely dissolved by adding water to the sample. The solubility of the actual sample may be higher than the measured solubility.

1H NMR shows the result of measurement using Bruker Advance 600 MHz NMR spectrometer.

Herein, the temperature values may have an error of ±5° C.

The crystalline form of the present invention may have higher purity than a crude compound of formula 1, an amorphous compound of formula 1, other pharmaceutically acceptable salts of the compound of formula 1, or other crystalline forms of the compound of formula 1, and may be physically and chemically more stable.

In addition, the agonistic ability for the melanocortin-4 receptor and preventive or therapeutic effects on diseases, such as obesity, diabetes, inflammation, erectile dysfunction, or the like, of the crystalline form of the sulfate of the compound of formula 1, may be more excellent than those of known melanocortin-4 receptor agonists. However, the effects of the present invention are not limited thereto.

In another aspect, the present invention provides a method for preparing a crystalline form, comprising the steps of: preparing a mixed solution in which the compound of formula 1 and sulfuric acid (H2SO4) are mixed; and obtaining crystals from the mixed solution.

The compound of formula 1 for preparing the crystalline form may be a compound of formula 1, a salt thereof, an isomer thereof, or a solvate thereof.

The compound of formula 1 may be obtained by the preparation method described in the specification of application no. KR 10-2019-0141649 (filed on 7 Nov. 2019).

First, a mixed solution is prepared by mixing the compound of formula 1 and sulfuric acid, for example, an aqueous sulfuric acid solution.

The aqueous sulfuric acid solution may contain, for example, sulfuric acid in an amount of 90 wt % to 99 wt %, specifically 95 wt % to 97 wt %. However, the present invention is not limited thereto.

In one embodiment, according to the present invention, sulfuric acid may be contained in an excess molar ratio compared to the compound of formula 1 in the mixed solution. For example, the molar ratio of the compound of formula 1 and sulfuric acid in the mixed solution may be 1:1 to 1:2.

Mixing of the crude compound of formula 1 with sulfuric acid may be carried out without or with stirring at room temperature, for example, 15 to 30° C., and specifically, at a temperature of 23 to 28° C.

Before mixing with sulfuric acid, the compound of formula 1 may be provided in a dissolved state in an appropriate solvent, and thus the mixed solution may include a solvent in which the compound of formula 1 has been dissolved.

The solvent with which the compound of formula 1 is provided together may be, for example, an acetate-based solvent, and the acetate-based solvent may include, but is not limited to, for example, at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, n-butyl acetate, t-butyl acetate, and isobutyl acetate.

In one embodiment, according to the present invention, the compound of formula 1 may be dissolved and present in isobutyl acetate solvent, and thus the mixed solution may include isobutyl acetate.

Next, crystals are obtained from the mixed solution in which the compound of formula 1 and sulfuric acid have been dissolved.

The crystals may be obtained, for example, by cooling the solution, by evaporating the solvent, by adding an antisolvent for supersaturation, or by using methods, such as slurry conversion, or the like.

In one embodiment, according to the present invention, the step of obtaining crystals may include slurrying the mixed solution.

The step of obtaining crystals may be slurrying the mixed solution through stirring to produce a solid, and filtering the produced solid.

In one embodiment, according to the present invention, stirring may be carried out, for example, at room temperature, for 1 to 3 days, for example, for 1 day.

In one embodiment, according to the present invention, the crystalline form obtained as described above may be a crystalline form of the sulfate of the compound of formula 1.

In another embodiment, according to the present invention, since the mixed solution may contain the solvent in which the compound of formula 1 has been dissolved before the compound of formula 1 is mixed with sulfuric acid, the crystalline form obtained as described above may be a crystalline form of the sulfate of a solvate of the compound of formula 1.

In another embodiment, according to the present invention, the crystalline form obtained as described above may be a crystalline form of the sulfate of the solvate with isobutyl acetate of the compound of formula 1 (herein, also referred to as ‘crystalline form A’).

In another aspect, the present invention may further include a step for drying and recrystallizing the obtained crystals.

In one embodiment, according to the present invention, a new crystalline form of the compound of formula 1 (herein, also referred to as ‘crystalline form B’) may be obtained by drying the crystalline form A obtained above.

In one embodiment, according to the present invention, drying may be vacuum drying at 40 to 60° C., for example, 45° C.

In one embodiment, according to the present invention, a new crystalline form of the sulfate of the compound of formula 1 may be prepared by vacuum drying the crystalline form A obtained above at 45° C.

In one embodiment, according to the present invention, it can be confirmed that the new crystalline form B is prepared from the crystalline form A by the fact that characteristic peaks of the X-ray powder diffraction patterns (XRPD) between the crystalline form A and the crystalline form B are different.

The crystalline form obtained as described above may have higher purity than the crude compound of formula 1, the amorphous compound of formula 1, other pharmaceutically acceptable salts of the compound of formula 1, or any crystalline forms of formula 1. In addition, due to the suppressed decomposition and moisture absorption, the crystalline form may be physically and chemically more stable, and thus may be easily applied to the preparation of a pharmaceutical composition. In addition, thanks to improved solubility, disintegration and dissolution rates of a pharmaceutical may be improved, and thus, it may be preferable to use the crystalline form as a raw material for a pharmaceutical.

In another aspect, the present invention provides a pharmaceutical composition comprising: (i) the crystalline form; and (ii) a pharmaceutically acceptable carrier.

The crystalline form, according to the present invention, exhibits excellent agonistic actions on melanocortin receptors, in particular, melanocortin-4 receptors (MC4R). Thus, the present invention can provide a pharmaceutical composition for agonizing melanocortin receptors, the composition containing the above-described crystalline form as an active ingredient. Specifically, the pharmaceutical composition may be a composition for agonizing the function of the melanocortin-4 receptor.

In addition, since the pharmaceutical composition can exhibit excellent effects of preventing or treating obesity, diabetes, inflammation, and erectile dysfunction, it may be a composition for preventing or treating obesity, diabetes, inflammation, or erectile dysfunction. However, the use of the present invention is not limited the diseases.

As used herein, “carrier” refers to a compound that facilitates the introduction of compounds into a cell or tissue.

When the crystalline form of the present invention is administered for clinical purposes, the total daily dose to be administered to a host in a single dose or in divided doses may be preferably in the range of 0.01 to 10 mg/kg body weight. However, the specific dose level for an individual patient may vary depending on the specific compound to be used, the patient's weight, sex, health status, diet, administration time of the drug, administration method, excretion rate, drug combination, the severity of the disease, or the like.

The crystalline form of the present invention may be administered by any route as desired. For example, the crystalline form of the present invention may be administered by injection or orally.

The pharmaceutical composition of the present invention may be in various oral dosage forms, such as tablets, pills, powders, capsules, granules, syrups, or emulsions, or parenteral dosage forms, such as injection preparations for intramuscular, intravenous, or subcutaneous administration.

Preparations for injection may be prepared, according to known techniques, using suitable dispersing agents, wetting agents, suspending agents, or excipients.

When the pharmaceutical composition of the present invention is in an oral dosage form, examples of the carrier to be used may include, but are not limited to, cellulose, calcium silicate, corn starch, lactose, sucrose, dextrose, calcium phosphate, stearic acid, magnesium stearate, calcium stearate, gelatin, talc, etc.

When the pharmaceutical composition of the present invention is in an injectable preparation form, examples of the carrier may include, but are not limited to, water, saline, aqueous glucose solution, an aqueous sugar-like solution, alcohols, glycol, ethers, oils, fatty acids, fatty acid esters, glycerides, etc.

In another aspect, there is provided a crystalline form as described above for use in agonizing the functions of melanocortin receptors, in particular, melanocortin-4 receptors (MC4R).

In one embodiment, there is provided a crystalline form as described above for use in treating or preventing obesity, diabetes, inflammation, or erectile dysfunction.

In another aspect, there is provided a method for agonizing the function of melanocortin receptors, in particular, melanocortin-4 receptors (MC4R), the method comprising a step for administering to a subject the above-described crystalline form.

In another aspect, there is provided a method for treating obesity, diabetes, inflammation, or erectile dysfunction, the method comprising a step for administering to a subject the above-described crystalline form.

Advantageous Effects

The crystalline form, according to the present invention, exhibits excellent agonistic action on melanocortin receptors, in particular, melanocortin-4 receptors (MC4R), and thus can be usefully used for preventing or treating obesity, diabetes, inflammation, and erectile dysfunction.

The crystalline form, according to the present invention, exhibits an on-target effect on melanocortin-4 receptors, thereby exhibiting weight loss and diet reduction effects, without affecting anxiety and depression. In addition, it can be administered without any safety issues, such as side effects of human ether-a-go-go related gene (hERG) inhibition or mutagenesis.

In addition, the crystalline form, according to the present invention, has purity, yield, physical and chemical stability, which are more excellent than the crude compound of formula 1, the amorphous compound of formula 1, other pharmaceutically acceptable salts of the compound of formula 1, or any other crystalline forms of formula 1.

Specifically, the crystalline form may have superior solubility, storage stability, and production stability to the compound of formula 1, the amorphous compound of formula 1, other pharmaceutically acceptable salts of the compound of formula 1, or any other crystalline forms of formula 1.

Hereinafter, the present invention will be described in more detail through Preparation Examples and Examples. However, these Examples are merely illustrative of the present invention, and the scope of the present invention is not limited thereto.

Preparation Example 1: Preparation of methyl (2S,4S)-4-(N-((1 s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-2-carboxylate hydrochloride

The title compound was obtained through the following steps A, B, C, D, and E.

1-(tert-butyl) 2-methyl (2S,4R)-4-((methylsulfonyl)oxy)pyrrolidine-1,2-dicarboxylate (48.5 g, 150 mmol) was dissolved in N,N′-dimethylformamide (250 ml) under nitrogen, and sodium azide (19.5 g, 300 ml) was added. After stirring at 80° C. for 16 hours, the reaction solvent was concentrated under reduced pressure, water was added, and extraction was performed twice with ethyl acetate. The organic layer was washed with an aqueous sodium chloride solution and water, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure to obtain crude 1-(tert-butyl) 2-methyl (2S,4S)-4-azidopyrrolidine-1,2-dicarboxylate (39.59 g, 98%), which was used in the next step without purification.

1-(tert-butyl) 2-methyl (2S,4S)-4-azidopyrrolidine-1,2-dicarboxylate (24.59 g, 91.0 mmol) obtained in step A above was dissolved in tetrahydrofuran (180 ml), and 1 M trimethylphosphine tetrahydrofuran solution (109.2 ml, 109.2 mmol) was slowly added at 0° C. The mixture was stirred at the same temperature for 1 hour and then at room temperature for 3 hours. After the reaction solvent was concentrated under reduced pressure, dichloromethane (100 ml) and water (150 ml) were added, and the mixture was stirred for about 30 minutes. The layers were separated and were extracted once more with dichloromethane, and the organic layer was dried over anhydrous magnesium sulfate and was filtered. The filtrate was concentrated under reduced pressure to obtain crude 1-(tert-butyl) 2-methyl (2S,4S)-4-aminopyrrolidine-1,2-dicarboxylate (20.62 g, 93%), which was used in the next step without purification.

1-(tert-butyl) 2-methyl (2S,4S)-4-aminopyrrolidine-1,2-dicarboxylate (20.62 g, 84.4 mmol) obtained in step B above was dissolved in dichloroethane (150 ml), and 4-methylcyclohexanone (9.5 ml, 101.3 mmol) was added. Sodium triacetoxyborohydride (26.8 g, 126.6 mmol) was added at 0° C., and the mixture was stirred at room temperature for 16 hours. The reaction solvent was concentrated under reduced pressure, water was added, and extraction was performed twice with ethyl acetate. The organic layer was washed with an aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure and purified by column chromatography to obtain 1-(tert-butyl) 2-methyl (2S,4S)-4-(((1 s,4R)-4-methylcyclohexyl)amino)pyrrolidine-1,2-dicarboxylate (22.9 g, 80%).

1-(tert-butyl) 2-methyl (2S,4S)-4-(((1 s,4R)-4-methylcyclohexyl)amino)pyrrolidine-1,2-dicarboxylate obtained in step C above (37.29 g, 109.5 mmol) was dissolved in dichloromethane (500 ml), triethyl amine (61.1 ml, 438.1 mmol) was added, and then isobutyryl chloride (11.7 ml, 219 mmol) was slowly added at 0° C. After the mixture was stirred at room temperature for 16 hours, the reaction solvent was concentrated under reduced pressure, an aqueous sodium hydrogen carbonate solution was added, and extraction was performed twice with ethyl acetate. The organic layer was washed with an aqueous sodium chloride solution and water, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure, and purified by column chromatography to obtain 1-(tert-butyl) 2-methyl (2S,4S)-4-(N-((1 s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-1,2-dicarboxylate (38.79 g, 86%).

Step E: Preparation of methyl (2S,4S)-4-(N-((1s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-2-carboxylate hydrochloride

1-(tert-butyl) 2-methyl (2S,4S)-4-(N-((1 s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-1,2-dicarboxylate (34.0 g, 82.8 mmol) obtained in step D above was dissolved in dichloromethane (200 ml), and a solution of 4 N hydrochloric acid in 1,4-dioxane solution (82.8 ml, 331.3 mmol) was added at 0° C. After the mixture was stirred at room temperature for 6 hours, the reaction solvent was concentrated under reduced pressure to obtain crude (28.7 g, 99%), which was used in the next step without purification.

Preparation Example 2: Preparation of (3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carboxylic acid

The title compound was obtained according to the method described in international patent publication no. WO 2004/092126.

Preparation Example 3: Preparation of N-((3S,5S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)

The title compound was obtained through the following steps A, B, and C.

Step A: Preparation of methyl (2S,4S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-4-(N-((1 s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-2-carboxylate

Methyl (2S,4S)-4-(N-((1 s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-2-carboxylate hydrochloride (28.7 g, 82.73 mmol) obtained in Preparation Example 1, (3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carboxylic acid (24.5 g, 86.87 mmol) obtained in Preparation Example 2, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (22.2 g, 115.83 mmol), and 1-hydroxybenzotriazole hydrate (15.7 g, 115.83 mmol) were dissolved in N,N′-dimethylformamide (400 ml), and N,N′-diisopropylethylamine (72.0 ml, 413.66 mmol) was added slowly. The mixture was stirred at room temperature for 16 hours, the reaction solvent was concentrated under reduced pressure, 0.5 N sodium hydroxide aqueous solution was added, and then, extraction was performed twice with ethyl acetate. The organic layer was washed twice with sodium chloride aqueous solution and water, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure and purified by column chromatography to obtain methyl (2S,4S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-4-(N-((1 s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-2-carboxylate (41.19 g, 87%).

Methyl (2S,4S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-4-(N-((1 s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-2-carboxylate (39.4 g, 68.62 mmol) obtained in step A above was dissolved in methanol (450 ml), and then, 6 N sodium hydroxide aqueous solution (57.2 ml, 343.09 mmol) was added. The mixture was stirred at room temperature for 16 hours, the pH was adjusted to about 5 with 6 N aqueous hydrochloric acid solution, and then the reaction solution was concentrated under reduced pressure. The concentrate was dissolved in dichloromethane, and then the insoluble solid was filtered through a paper filter. The filtrate was concentrated under reduced pressure to obtain the crude title compound (38.4 g, 99%), which was used in the next step without purification.

(2S,4S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-4-(N-((1 s,4R)-4-methylcyclohexyl)isobutyramido)pyrrolidine-2-carboxylic acid (38.4 g, 68.60 mmol) obtained in step B above, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (18.4 g, 96.04 mmol), and 1-hydroxybenzotriazole hydrate (13.0 g, 96.04 mmol) were dissolved in N,N′-dimethylformamide (200 ml), and then morpholine (5.9 ml, 68.80 mmol) and N,N′-diisopropylethylamine (59.7 ml, 343.02 mmol) were sequentially and slowly added. The mixture was stirred at room temperature for 16 hours, the reaction solution was concentrated under reduced pressure, 0.5 N sodium hydroxide aqueous solution was added, and then extraction was performed twice with ethyl acetate. The organic layer was washed twice with sodium chloride aqueous solution and water, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure and purified by column chromatography to obtain N-((3S,5S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-5-(morpholine-4-carbonyl)pyrrolidin-3-yl)-N-((1 s,4R)-4-methylcyclohexyl)isobutyramide (37.05 g, 86%, MC70).

Example 1: Preparation of crystalline form A of N-((3S,5S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-5-(morpholine-4-carbonyl)pyrrolidin-3-yl)-N-((1 s,4R)-4-methylcyclohexyl)isobutyramide sulfate

To a solution of the compound (MC70) prepared in Preparation Example 3 in isobutyl acetate, 95 wt % to 97 wt % of aqueous sulfuric acid solution was added so that MC70 and sulfuric acid were in an equivalent ratio of 1:1. Then, the mixture was stirred at room temperature for 1 day to obtain the title compound (crystalline form A of the sulfate of MC70).

Example 2: Preparation of crystalline form B of N-((3S,5S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-5-(morpholine-4-carbonyl)pyrrolidin-3-yl)-N-((1 s,4R)-4-methylcyclohexyl)isobutyramide sulfate

The crystalline form A according to Example 1 was vacuum dried at 45° C. to obtain the title compound (crystalline form B of the sulfate of MC70).

Comparative Example 1: Preparation of crystalline form of N-((3S,5S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-5-(morpholine-4-carbonyl)pyrrolidin-3-yl)-N-((1 s,4R)-4-methylcyclohexyl)isobutyramide phosphate

The compound (MC70) prepared in Preparation Example 3 was dissolved in 1-propyl alcohol, and 85% aqueous phosphoric acid solution was added so that the molar ratio of MC70:H3PO4 was 1:1, and stirring was carried out to prepare a mixed solution. It was confirmed that the mixed solution was maintained as a clear solution, so heptane was added to the mixed solution, and stirring was carried out at room temperature for 4 days. Then, the stirring temperature was increased to 40° C., 50° C., and 60° C., respectively, and stirring was further carried out for 1 day, 17 days, and 6 days in sequence. However, no crystals formed.

Comparative Example 2: Preparation of crystalline form of N-((3S,5S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-5-(morpholine-4-carbonyl)pyrrolidin-3-yl)-N-((1 s,4R)-4-methylcyclohexyl)isobutyramide phosphate

The compound (MC70) prepared in Preparation Example 3 was dissolved in ethanol, and 85% aqueous phosphoric acid solution was added so that the molar ratio of MC70:H3PO4 was 1:1, and stirring was carried out to prepare a mixed solution. It was confirmed that the mixed solution was maintained as a clear solution, so cyclohexane was added to the mixed solution, and stirring was carried out at room temperature for 4 days. Then, the stirring temperature was increased to 35° C., 50° C., and 60° C., respectively, and stirring was further carried out for 4 days, 3 days, and 3 days in sequence. However, no crystals formed.

Comparative Example 3: Preparation of crystalline form of N-((3S,5S)-1-((3S,4R)-1-(tert-butyl)-4-(4-chlorophenyl)pyrrolidine-3-carbonyl)-5-(morpholine-4-carbonyl)pyrrolidin-3-yl)-N-((1 s,4R)-4-methylcyclohexyl)isobutyramide phosphate

The compound (MC70) prepared in Preparation Example 3 was dissolved in acetone, and 85% aqueous phosphoric acid solution was added in excess so that the molar ratio of MC70:H3PO4 was 1:8, and stirring was carried out to prepare a mixed solution. It was confirmed that the mixed solution was maintained as a clear solution, so hexane was added to the mixed solution, and stirring was carried out at room temperature for 4 days. Then, the stirring temperature was increased to 40° C., 50° C., and 60° C., respectively, and stirring was further carried out for 3 days, 1 day, and 1 day in sequence. However, no crystals formed.

Powder XRPD diffraction patterns were obtained with Panalytical Xpert Pro MPD diffractometer using an incident beam of Cu radiation. About 20 to 30 mg of the sample was compressed in a glass sample holder so that the sample had a flat surface, the generator of the apparatus was set to 45 kV (acceleration voltage) and 40 mA (filament emission), and then, the measurement was carried out in a reflection mode (not-spin). Bragg angles (26) in a range of 4 to 400were measured with the conditions of step size of 0.0260and time per step of 51 seconds.

As can be seen from the spectrum shown inFIG.1, it was confirmed that the crystalline form A of the sulfate according to Example 1 was a crystalline substance. The specific values of the XRPD are shown in Table 1 below.

As can be seen from the spectrum shown inFIG.2, it was confirmed that the crystalline form B of the sulfate according to Example 2 was a crystalline substance. The specific values of the XRPD are shown in Table 2 below.

From the XRPD results ofFIGS.1and2, it was confirmed that new crystalline form B was formed from crystalline form A.

Experimental Example 2. Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC)

TGA and DSC combo analysis was performed with Mettler-Toledo TGA/DSC 3+ analyzer. The sample was placed in an open aluminum pan, the pan was sealed, the lid was pierced, and then the pan was inserted into the TG furnace. Measurements were made by heating from 25° C. to a maximum of 350° C. at a rate of K/min under nitrogen.

As can be seen inFIG.3, according to the TGA analysis result, the crystalline form B of the sulfate according to Example 2 had a weight loss of about 8.9 wt % in a temperature range of about 40° C. to 150° C. and was decomposed beyond about 248° C.

In addition, according to the DSC analysis result, for the crystalline form B of the sulfate according to Example 2, endothermic peaks were observed at about 104° C. (peak) and 136° C. (peak), and an exothermic peak was observed at about 145° C. (peak).

Experimental Example 3. Hot Stage Microscopy (HSM)

HSM was measured with Leica DM LP microscope using Linkman hot stage (model FTIR 600) with TMS 93 controller. Samples were observed with a lambda plate with crossed polarizers at either 10×0.22 or 20×0.40 magnification. Samples were placed on a coverslip, and another coverslip was placed over the sample. Then, the sample was visually observed as the stage was heated. In order to investigate outgassing, in some cases, a drop of mineral oil may be added to the sample. Images were captured using SPO Insight color digital camera with SPOT software v.4.5.9.

As can be seen inFIGS.4to6, according to the HSM analysis result, it was confirmed that the crystalline form B of the sulfate according to Example 2 started melting from about 133.7° C. and the melting was completed at 155.1° C.

Experimental Example 4. Solubility Assessment

Solubility was measured based on the final volume of water added to a sample when it was visually confirmed that the sample was completely dissolved by adding water to the sample.

According to the assessment result, the solubility of the crystalline form B of the sulfate according to Example 2 was more than 56 mg/mL. As described above, it was confirmed that the crystalline form B according to Example 2 had excellent solubility in water.