Novel method for preparing diaminopyrimidine derivative or acid addition salt thereof

Abstract

The present invention provides a novel process for preparing a diaminopyrimidine derivative having 5-HT4 receptor agonist activity or an acid addition salt thereof. The invention also provides a novel crystal form of the hydrochloride of the diaminopyrimidine derivative and a preparation method thereof.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201980033332.0, filed on May 16, 2019, entitled "A Novel Method for Preparing Diaminopyrimidine Derivatives or Acid Addition Salts thereof", and claims priority to Korean Patent Application No. 10-2018-0057088, filed with the Korean Intellectual Property Office (KIPO) on May 18, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to a novel method for preparing diaminopyrimidine derivatives or their acid addition salts having 5-HT4 receptor agonist activity. The invention also relates to novel crystal forms of diaminopyrimidine derivative hydrochlorides and their preparation methods. Background Technology

[0003] The chemical name of the diaminopyrimidine derivative of Formula 1 is (S)-N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidine-3-yl)acetamide. The diaminopyrimidine derivative of Formula 1 or a pharmaceutically acceptable salt (e.g., hydrochloride) has the function of a 5-HT4 receptor agonist and is therefore effective for the prevention or treatment of gastrointestinal motility disorders, which are a type of gastrointestinal disease such as gastroesophageal reflux disease (GERD), constipation, irritable bowel syndrome (IBS), dyspepsia, postoperative intestinal obstruction, delayed gastric emptying, gastroparesis, pseudo-obstruction, drug-induced delayed transport, or diabetic gastric atony (WO 2012 / 115480).

[0004] <Formula 1>

[0005]

[0006] WO 2012 / 115480 discloses a method for preparing a compound of formula 1. Specifically, as shown in reaction scheme 1 below, the method for preparing a compound of formula 1 or a pharmaceutically acceptable salt thereof includes reacting a compound of formula (I) with POCl3 to prepare a compound of formula (II); reacting a compound of formula (II) with a compound of formula (III) in the presence of a base to prepare a compound of formula (IV); reacting a compound of formula (IV) with a compound of formula (V) to prepare a compound of formula 1; and optionally converting a compound of formula 1 into a pharmaceutically acceptable salt thereof.

[0007] <Reaction Scheme 1>

[0008]

[0009] In the method of reaction scheme 1, the compound of formula (II) is prepared by reacting with excess POCl3 at a high temperature above 100°C, thus generating a high content of impurities. Therefore, in order to remove the impurities, the reaction requires a purification step using column chromatography, which is not suitable for industrial-scale production. Furthermore, the compound of formula (II) is obtained in the form of an oil; and it is easily decomposed at room temperature, thus causing stability problems, i.e., low stability.

[0010] In particular, because the compound of formula (II) has two reactive sites (i.e., positions 2 and 4 of the pyrimidine ring), a large amount of structural isomeric impurity is generated, which is the 2-position of the pyrimidine ring of the compound of formula (III). Therefore, the reaction of the compound of formula (II) with the compound of formula (III) exhibits a very low yield of approximately 55-60%, leading to the problem of structural isomeric impurities remaining in the final product (i.e., the compound of formula 1).

[0011] Furthermore, in the reaction between the compound of formula (IV) and the compound of formula (V), the compound of formula (V) is known to be genotoxic. Therefore, in order to avoid the compound of formula (V) remaining in the final product (i.e., the compound of formula 1), there is a problem of using column chromatography, which is not suitable for industrial-scale production, for purification steps.

[0012] Furthermore, WO2012 / 115480 discloses a step for converting a compound of Formula 1 into its hydrochloride salt. The conversion step involves reacting the compound of Formula 1 with hydrochloric acid in ethyl acetate, stirring at room temperature for 1 hour, and then filtering the product. The inventors have discovered that the hydrochloride salt of the compound of Formula 1 obtained by said method is in an amorphous form, leading to a significant amount of deacetylation impurities when stored at room temperature. Summary of the Invention

[0013] Technical issues

[0014] To develop a new method capable of solving the problems of existing techniques for preparing compounds of formula (II) or acid addition salts, the inventors have conducted various studies. In particular, the inventors have conducted various studies to develop a new method that avoids the use of compounds of formula (II), i.e., intermediates that are unstable, difficult to handle, and lead to the formation of structurally isomeric impurities. As a result, the inventors have developed a new method comprising forming a pyrimidine ring from a substituted phenylguanidine derivative or a salt thereof, activating the pyrimidine ring to prepare a novel intermediate, and reacting the novel intermediate with (S)-3-acetamidopyrrolidine. It has been found that the method solves the problems of existing techniques and is suitable for industrial-scale production.

[0015] Furthermore, the inventors have isolated a new crystal form of the hydrochloride salt of the compound of Formula 1 and found that the crystal form exhibits very superior stability compared to the amorphous form according to the prior art.

[0016] Therefore, the object of the present invention is to provide a method for preparing diaminopyrimidine derivatives or their acid addition salts, the method comprising using a novel intermediate.

[0017] Furthermore, another objective of this invention is to provide the novel intermediate and its preparation method.

[0018] Furthermore, another object of the present invention is to provide the crystal form of the hydrochloride salt of the compound of Formula 1 and a method for preparing the same.

[0019] Technical solution

[0020] According to one aspect of the invention, a method for preparing a compound of formula 1 or an acid addition salt thereof is provided, the method comprising (a) reacting a compound of formula 2 or a salt thereof with (S)-3-acetamidopyrrolidine to prepare a compound of formula 1; and optionally (b) reacting a compound of formula 1 with an acid to prepare an acid addition salt of a compound of formula 1:

[0021] <Formula 1>

[0022]

[0023] <Formula 2>

[0024]

[0025] Among them, R 1 It is a C1-C3 alkyl group, or a phenyl group optionally substituted with one or more substituents selected from halogen, C1-C3 alkyl and cyano.

[0026] According to another aspect of the invention, a compound of formula 2 or a salt thereof is provided:

[0027] <Formula 2>

[0028]

[0029] Among them, R 1 Same as defined above.

[0030] According to another aspect of the present invention, a method for preparing a compound of formula 2 or a salt thereof is provided, the method comprising: (i) reacting a compound of formula 5 or a salt thereof with methyl 3-oxohexanoate to prepare a compound of formula 4; (ii) reacting a compound of formula 4 with R 1 - sulfonyl halide reaction to prepare compounds of formula 2; and optionally (iii) to convert compounds of formula 2 into their salts:

[0031] <Formula 4>

[0032]

[0033] <Formula 5>

[0034]

[0035] According to another aspect of the invention, a crystal form A of the hydrochloride salt of the compound of formula 1 is provided, the XRPD spectrum of which has peaks at 7.4°, 9.1°, 12.0°, 12.5°, 13.5°, 14.1°, 15.9°, 16.8°, 18.3°, 19.1°, 24.6°, 25.3° and 26.8°2θ±0.2°2θ.

[0036] <Formula 1>

[0037]

[0038] According to another aspect of the invention, a method for preparing a crystal form A of the hydrochloride salt of a compound of formula 1 is provided, the method comprising (p) refluxing a reaction mixture obtained by adding hydrochloric acid to a compound of formula 1 in an organic solvent; (q) cooling the reaction mixture obtained from step (p) to form a precipitate; and (r) separating the precipitate from step (q).

[0039] According to another aspect of the invention, a crystal form B of the hydrochloride salt of the compound of formula 1 is provided, the XRPD spectrum of which has peaks at 7.3°, 8.8°, 11.8°, 12.5°, 13.2°, 13.6°, 14.5°, 17.7°, 18.6°, 19.6°, 22.0°, 24.9°, 25.2° and 25.9°2θ±0.2°2θ.

[0040] <Formula 1>

[0041]

[0042] According to another aspect of the present invention, a method for preparing a crystal form B of the hydrochloride salt of a compound of formula 1 is provided, the method comprising exposing a crystal form A of the hydrochloride salt of a compound of formula 1 to a relative humidity of 40% or more to control its moisture content to about 3.5% or more.

[0043] Beneficial effects of the invention

[0044] The method of the present invention is carried out by using a novel intermediate, namely a compound of formula 2 or a salt thereof obtained from a substituted phenylguanidine derivative or a salt thereof. Therefore, the method of the present invention avoids the use of compounds of formula (II), i.e., unstable, difficult-to-handle intermediates that lead to the formation of structurally isomeric impurities. Furthermore, the method of the present invention can provide compounds of formula 1 or their acid addition salts in high yield and purity, and is suitable for industrial mass production. In addition, the novel crystal forms of the hydrochloride salts of compounds of formula 1, namely crystal form A and crystal form B, exhibit very superior stability compared to the amorphous forms according to the prior art. Attached Figure Description

[0045] Figure 1 The XRPD spectrum of crystal form A of the hydrochloride salt of compound of formula 1 is shown.

[0046] Figure 2 The XRPD spectrum of crystal form B of the hydrochloride salt of compound of formula 1 is shown. Detailed Implementation

[0047] The present invention provides a method for preparing a compound of formula 1 or an acid addition salt thereof, the method comprising: (a) reacting a compound of formula 2 or a salt thereof with (S)-3-acetamidopyrrolidine to prepare a compound of formula 1; and optionally (b) reacting a compound of formula 1 with an acid to prepare an acid addition salt of a compound of formula 1.

[0048] <Formula 1>

[0049]

[0050] <Formula 2>

[0051]

[0052] Among them, R 1 It is a C1-C3 alkyl group, or a phenyl group optionally substituted with one or more substituents selected from halogen, C1-C3 alkyl and cyano.

[0053] In the method of the present invention, one of the reactants, (S)-3-acetamidopyrrolidine, is a known and commercially available compound. Furthermore, (S)-3-acetamidopyrrolidine can also be formed by removing the protection of the amino protecting group from a commercially available compound of formula 3.

[0054] <Formula 3>

[0055]

[0056] Among them, R 2 It is an amino protecting group, such as tert-butoxycarbonyl.

[0057] Deprotection can be carried out using one or more acids selected from hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, acetic acid, formic acid, sulfonic acid, p-toluenesulfonic acid, and methanesulfonic acid, preferably p-toluenesulfonic acid or hydrochloric acid. Deprotection can also be carried out in one or more solvents selected from dichloromethane, dichloroethane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, ethyl acetate, and toluene, preferably in toluene. Furthermore, deprotection can be carried out at a temperature from 0°C to 40°C, preferably from 10°C to 30°C.

[0058] In one embodiment, the deprotection and reaction of the formed (S)-3-acetamidopyrrolidine with the compound of Formula 2 or a salt thereof can be carried out in a one-pot reaction. That is, in the method of the present invention, step (a) may include (a1) deprotecting the compound of Formula 3 to form (S)-3-acetamidopyrrolidine; and (a2) reacting the compound of Formula 2 or a salt thereof by adding it to the reaction mixture of step (a1). The reaction of the compound of Formula 2 or a salt thereof with (S)-3-acetamidopyrrolidine can be carried out in the presence of a base. The base may be selected from one or more of the following: potassium tert-butoxide, sodium hydroxide, potassium hydroxide, sodium hydride, sodium carbonate, potassium carbonate, potassium phosphate (including potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and tripotassium phosphate), sodium phosphate (including sodium dihydrogen phosphate, disodium hydrogen phosphate, and trisodium phosphate), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), pyridine, triethylamine, diisopropylamine, and diisopropylethylamine. Preferably, the base may be triethylamine or diisopropylethylamine. More preferably, the base may be diisopropylethylamine. The reaction of the compound of Formula 2 or its salt with (S)-3-acetamidopyrrolidine can be carried out at a temperature of 40°C to 130°C, preferably 80°C to 90°C.

[0059] In the method of the present invention, the acid used in step (b) can be a conventional inorganic or organic acid suitable for forming the desired acid addition salt. Preferably, the acid used in step (b) can be hydrochloric acid. When hydrochloric acid is used in step (b), the product is obtained in the form of a hydrochloride salt of the compound of formula 1.

[0060] In the method of the present invention, the compound of formula 2 or a salt thereof can be prepared or formed by a method comprising the following steps: (i) reacting the compound of formula 5 or a salt thereof with methyl 3-oxohexanoate to prepare the compound of formula 4; (ii) reacting the compound of formula 4 with R 1 - sulfonyl halide reaction to prepare compounds of formula 2; and optionally (iii) to convert compounds of formula 2 into their salts:

[0061] <Formula 4>

[0062]

[0063] <Formula 5>

[0064]

[0065] In the reaction of step (i), the compound of formula 5 can be prepared by reacting 4-amino-2-nitroaniline with cyanamide under acidic conditions, according to known methods such as US6,562,854B2. The salt of the compound of formula 5 can be in the form of a 1-(4-amino-3-nitrophenyl)guanidine hemicarbonate. The reaction of step (i), i.e., the cyclization reaction, can be carried out in a C1-C5 alcohol, preferably in n-butanol. Moreover, the cyclization reaction can be carried out at a temperature of 50°C to 130°C, preferably 90°C to 120°C.

[0066] The reaction in step (ii), i.e., the reaction of the compound of formula 4 with R 1 The reaction of -sulfonyl halides can be carried out in the presence of a base. The base can be one or more selected from the following: potassium tert-butoxide, sodium hydroxide, potassium hydroxide, sodium hydride, sodium carbonate, potassium carbonate, potassium phosphate (including potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and tripotassium phosphate), sodium phosphate (including sodium dihydrogen phosphate, disodium hydrogen phosphate, and trisodium phosphate), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), pyridine, triethylamine, diisopropylamine, and diisopropylethylamine. Preferably, the base can be triethylamine. The compound of Formula 4 reacts with R... 1 The reaction of -sulfonyl halides can be carried out with or without a solvent. When the reaction is carried out in the presence of a solvent, the solvent can be one or more selected from the following: acetone, methyl ethyl ketone, dichloromethane, dichloroethane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, C1-C5 alcohols, ethyl acetate, and toluene. Furthermore, the compound of formula 4 reacts with R... 1 The reaction of -sulfonyl halides can be carried out in a temperature range from 0°C to 60°C. If necessary, the compound of formula 4 can be reacted with R by reacting with an acid (such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, acetic acid, formic acid, or sulfonic acid). 1The compound of formula 2 obtained from the sulfonyl halide reaction is then converted to its salt form (e.g., to an acid addition salt). The obtained compound of formula 2 or its salt can be isolated. Furthermore, the obtained compound of formula 2 or its salt can be used directly in a subsequent reaction, i.e., with (S)-3-acetamidopyrrolidine, without isolation. In one embodiment, the reaction mixture of step (ii) can be used directly in the reaction of step (a) without the isolation of the compound of formula 2 or its salt.

[0067] An example of all the reaction steps of the present invention is shown in reaction scheme 2 below.

[0068] <Reaction Scheme 2>

[0069]

[0070] In reaction scheme 2, R 1 Same as defined above.

[0071] The present invention also provides a method for preparing a compound of formula 1 or an acid addition salt thereof, or a compound of formula 2 or a salt thereof:

[0072] <Formula 2>

[0073]

[0074] Among them, R 1 Same as defined above.

[0075] The present invention also provides a method for preparing a compound of formula 2 or a salt thereof. Specifically, the present invention provides a method for preparing a compound of formula 2 or a salt thereof, the method comprising: (i) reacting a compound of formula 5 or a salt thereof with methyl 3-oxohexanoate to prepare a compound of formula 4; (ii) reacting a compound of formula 4 with R… 1 - sulfonyl halide reaction to prepare compounds of formula 2; and optionally (iii) to convert compounds of formula 2 into their salts:

[0076] <Formula 4>

[0077]

[0078] <Formula 5>

[0079]

[0080] The reactions in steps (i) and (ii) are as described above.

[0081] The present invention also provides a new crystal form of the hydrochloride salt of the compound of formula 1 with excellent stability.

[0082] In one aspect, the present invention provides a crystal form A of the hydrochloride salt of a compound of formula 1, the XRPD spectrum of which has peaks at 7.4°, 9.1°, 12.0°, 12.5°, 13.5°, 14.1°, 15.9°, 16.8°, 18.3°, 19.1°, 24.6°, 25.3° and 26.8°2θ±0.2°2θ.

[0083] <Formula 1>

[0084]

[0085] Preferably, the crystal form A of the hydrochloride salt of the compound of formula 1 can have Figure 1 The XRPD spectrum of the compound of Formula 1. Furthermore, the crystal form A of the hydrochloride salt of Formula 1 can have a differential scanning calorimetry (DSC) thermogram showing an endothermic peak between 229°C and 235°C, preferably at 232±2°C. The onset temperature can be 230±2°C.

[0086] Within the scope of this invention, the invention also includes a method for preparing crystal form A of the hydrochloride salt of a compound of formula 1. Specifically, the invention provides a method for preparing crystal form A of the hydrochloride salt of a compound of formula 1. The method includes (p) refluxing a reaction mixture obtained by adding hydrochloric acid to a compound of formula 1 in an organic solvent; (q) cooling the reaction mixture obtained in step (p), typically to room temperature, to form a precipitate; and (r) separating the precipitate from step (q). The organic solvent in step (p) may be one or more selected from: acetone, methyl ethyl ketone, ethyl acetate, acetonitrile, tetrahydrofuran, heptane, and C1-C5 alcohols. For example, a mixed solvent of acetone and isopropanol may be used as the organic solvent. The ratio (volume ratio) of acetone to isopropanol in the mixed solvent may be in the range of 200 to 280:100, preferably in the range of about 250:100. Reflux may be carried out at a temperature of 50°C to 120°C, preferably 55°C to 70°C.

[0087] In another aspect, the present invention provides a crystal form B of the hydrochloride salt of the compound of formula 1, the XRPD spectrum of which has peaks at 7.3°, 8.8°, 11.8°, 12.5°, 13.2°, 13.6°, 14.5°, 17.7°, 18.6°, 19.6°, 22.0°, 24.9°, 25.2° and 25.9°2θ±0.2°2θ.

[0088] <Formula 1>

[0089]

[0090] Preferably, the crystal form B of the hydrochloride salt of the compound of formula 1 can have Figure 2The XRPD spectrum of the compound of formula 1. Furthermore, the crystal form B of the hydrochloride salt can have a differential scanning calorimetry (DSC) thermogram showing an endothermic peak between 229°C and 235°C, preferably at 232±2°C. The onset temperature can be 230±2°C.

[0091] Within the scope of this invention, the invention also includes a method for preparing crystal form B of the hydrochloride salt of a compound of formula 1. Specifically, the invention provides a method for preparing crystal form B of the hydrochloride salt of a compound of formula 1, the method comprising exposing crystal form A of the hydrochloride salt of a compound of formula 1 to a relative humidity of 40% or higher to control its moisture content to about 3.5% or higher.

[0092] The invention will be described in more detail with reference to the following embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0093] Preparation Example 1: 1-(4-amino-3-nitrophenyl)guanidine hemicarbonate

[0094] A mixture of 4-amino-2-nitroaniline (100.0 g, 0.653 mol), purified water (200 mL), concentrated hydrochloric acid (61.2 g, 0.588 mol), and cyanamide (35.7 g, 0.849 mol) was stirred at 80-90 °C for 3 hours. At approximately 65 °C, a solution of sodium carbonate (41.5 g, 0.392 mol) in purified water (500 mL) was slowly added to the reaction mixture. The reaction mixture was stirred for 2 hours, cooled to approximately 10 °C, and then filtered. The resulting solid was dried under vacuum to give 112.5 g of the title compound (yield: 76.2%).

[0095] 1 H-NMR(600MHz,DMSO)δ9.86(br,1H),7.80(s,1H),7.66(s,2H),7.56(s,2H),7.29(s,1H),7.15(s,1H)

[0096] Example 1: 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidine-4-ol

[0097] A mixture of 1-(4-amino-3-nitrophenyl)guanidine hemicarbonate (110.0 g, 0.486 mol), methyl 3-oxohexanoate (91.1 g, 0.632 mol), and n-butanol (330 mL) was stirred at 95 °C for 15 hours. The reaction mixture was cooled to room temperature and then filtered. The resulting solid was dried under reduced pressure to give 111.3 g of the title compound. (Yield: 79.1%, HPLC purity: 98.2%)

[0098] 1 H-NMR(400MHz,DMSO)δ10.82(br,1H),8.98(br,1H),8.57(s,1H),7.49(d,1H),7. 30(s,2H),7.02(d,1H),5.62(s,1H),2.35(t,2H),1.72-1.63(m,2H),0.91(t,3H)

[0099] Example 2: 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl-4-methylbenzenesulfonate

[0100] Triethylamine (37.2 g, 0.368 mol) was added to a solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol (106.5 g, 0.368 mol) and p-toluenesulfonyl chloride (64.27 g, 0.337 mol) in acetone (700 mL). The reaction mixture was stirred at room temperature for 3 hours and then filtered. Toluene (1065 mL) was added to the resulting filtrate, and the solution was concentrated to 430 mL to remove acetone. The resulting solution was used directly to prepare compounds of formula 1. A portion of the resulting solution was concentrated under reduced pressure to identify the product obtained from it. 1 The H-NMR spectral data are as follows.

[0101] 1 H-NMR(400MHz,DMSO)δ9.73(s,1H),8.33(br,1H),7.90(d,2H),7.56(d,1H),7.43(d,2H),7.3 2(s,2H),6.96(d,1H),6.44(s,1H),2.59(t,2H),2.40(s,3H),1.74-1.65(m,2H),1.18(t,3H)

[0102] Example 3: 4-Methylbenzenesulfonate of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl-4-methylbenzenesulfonate

[0103] Triethylamine (8.4 g, 0.083 mol) was added to a solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol (20.0 g, 0.069 mol) and p-toluenesulfonyl chloride (14.5 g, 0.076 mol) in acetone (170 mL). The reaction mixture was stirred at room temperature for 3 hours and then filtered. p-Toluenesulfonic acid (14.5 g, 0.076 mol) was added to the resulting filtrate. The mixture was stirred at room temperature for 2 hours and then filtered. The resulting solid was dried under reduced pressure to give 37.9 g of the title compound. (Yield: 89.1%)

[0104] 1 H-NMR (400MHz, CDCl3) δ11.70(s,1H),8.31(s,1H),7.81(d,2H),7.66(d,2H),7.56(d,1H),7.43(d,2 H),7.32(s,2H),6.96(d,1H),6.44(s,1H),2.59(t,2H),2.40(s,3H),1.74-1.65(m,2H),1.18(t,3H)

[0105] Example 4: 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl methanesulfonate was added to a solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol (18.0 g, 0.062 mol) and methanesulfonyl chloride (7.8 g, 0.068 mol) in N,N-dimethylformamide (54 mL). The reaction mixture was stirred at room temperature for 3 hours. Purified water (180 mL) and toluene (54 mL) were added to the reaction mixture, followed by filtration. The resulting solid was dried under reduced pressure to give 18.0 g of the title compound. (Yield: 79.0%)

[0106] 1 H-NMR(400MHz,DMSO)δ10.62(br,1H),8.76(br,1H),8.54(s,1H),7.48(d,1H),7.31(s, 2H),6.99(d,1H),5.66(s,1H),3.72(s,3H),2.34(t,2H),1.70-1.64(m,2H),0.91(t,3H)

[0107] Example 5: 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl-4-bromobenzenesulfonate

[0108] Triethylamine (4.2 g, 0.041 mol) was added to a solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol (10.0 g, 0.035 mol) and 4-bromobenzenesulfonyl chloride (9.7 g, 0.038 mol) in N,N-dimethylformamide (30 mL). The reaction mixture was stirred at room temperature for 3 hours. Purified water (180 mL) and toluene (54 mL) were added. The extracted organic layer was used directly to prepare the compound of formula 1. A portion of the organic layer was concentrated under reduced pressure to identify the product obtained. 1 The H-NMR spectral data are as follows.

[0109] 1 H-NMR(400MHz,DMSO)δ9.72(s,1H),7.96(br,2H),7.83(d,2H),7.56(d,1H),7.2 7(s,2H),6.98(d,1H),6.47(s,1H),2.59(t,2H),1.74-1.65(m,2H),0.90(t,3H)

[0110] Example 6: (S)-N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidine-3-yl)acetamide

[0111] To a mixture of tert-butyl(S)-3-acetamidopyrrolidine-1-carboxylate (70.0 g, 0.307 mol) and toluene (700 mL), p-toluenesulfonic acid monohydrate (116.7 g, 0.613 mol) was added. The reaction mixture was stirred at room temperature for 6 hours. To the reaction mixture, a toluene solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl-4-methylbenzenesulfonate obtained in Example 2 and diisopropylethylamine (198.1 g, 1.533 mol) were added. The reaction mixture was stirred at 80–90 °C for 5 hours, and then concentrated under reduced pressure. Methanol (210 mL) and 50% sodium bicarbonate solution (70 mL) were added to the residue. The resulting mixture was stirred at room temperature for 2 hours, and then distilled water (1050 mL) was added dropwise. After filtering the reaction mixture, the resulting solid was dried under reduced pressure to give 105.5 g of the title compound. (Yield: 86.0%, HPLC purity: 99.1%)

[0112] 1 H-NMR(400MHz,DMSO)δ8.99(s,2H),8.17(s,1H),7.58(d,1H),7.16(s,2H),6.93(d,1H),5.79(s ,1H),4.35(m,1H),3.70-3.35(m,6H),2.40(t,2H),1.82(s,3H),1.71-1.65(m,2H),0.92(t,3H)

[0113] Example 7: (S)-N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidine-3-yl)acetamide hydrochloride (Crystal form A)

[0114] Concentrated hydrochloric acid (2.6 g, 0.025 mol) was added to a mixture of (S)-N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidine-3-yl)acetamide (10.0 g, 0.025 mol), acetone (250 mL), and isopropanol (100 mL) at 50 °C. The reaction mixture was refluxed with stirring for 20 hours, cooled to room temperature, and then filtered. The resulting solid was dried under reduced pressure at about 60 °C to give 9.8 g of the title compound. (Yield: 90.0%, HPLC purity: 99.9%)

[0115] 1 H-NMR(600MHz)δ8.56(d,1H),7.37-7.34(m,1H),6.96-6.93(m,1H),6.09(d,1H),4.53-4.47(d,1H),3.91-3.43(m ,4H),2.62-2.58(m,2H),2.36-2.28(m,1H),2.12-2.05(m,1H),1.98(s,3H),1.78-1.74(m,2H),1.06-1.03(t,3H)

[0116] The obtained products were analyzed by X-ray powder diffraction (XRPD). The XRPD was performed using a Bruker D8 Advance diffractometer with Cu-Kα radiation. X-ray powder diffraction (XRPD) patterns were acquired at 40 kV and 40 mA. The patterns were acquired using 2θ scans from 4 to 40 in increments of 0.02 and a scan rate of 0.1 seconds per step (divergence slit: 0.3 and antiscattering slit: 0.3). The obtained XRPD patterns are shown below. Figure 1 As shown, Figure 1 Characteristic peaks are shown at 7.4°, 9.1°, 12.0°, 12.5°, 13.5°, 14.1°, 15.9°, 16.8°, 18.3°, 19.1°, 24.6°, 25.3°, and 26.8°2θ±0.2°2θ.

[0117] In addition, the obtained products were analyzed by differential scanning calorimetry (DSC). The DSC analysis was performed using a Mettler Toledo DSC 1STAR differential scanning calorimeter. The analytical conditions were as follows: sample placed in an aluminum dish; aluminum cap (pinhole) placed on the dish; 99% nitrogen purging (gas flow rate: 50 mL / min); initial temperature 30 °C; final temperature 300 °C; heating rate 10 °C / min. As a result, an endothermic peak was observed between 229 °C and 235 °C. The onset temperature was 230.4 °C, and the maximum peak value was observed at 233.0 °C.

[0118] Example 8: (S)-N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidine-3-yl)acetamide hydrochloride (crystal form B)

[0119] The crystal form A of (S)-N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidine-3-yl)acetamide hydrochloride prepared in Example 7 was exposed in a humid chamber with a relative humidity of 40% for more than 5 hours to obtain the title compound.

[0120] 1 H-NMR(600MHz)δ8.56(d,1H),7.37-7.34(m,1H),6.96-6.93(m,1H),6.09(d,1H),4.53-4.47(d,1H),3.91-3.43(m ,4H),2.62-2.58(m,2H),2.36-2.28(m,1H),2.12-2.05(m,1H),1.98(s,3H),1.78-1.74(m,2H),1.06-1.03(t,3H)

[0121] The obtained product was analyzed by X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) using the same method as in Example 7. The obtained XRPD pattern is shown below. Figure 2 middle, Figure 2 Characteristic peaks are shown at 7.3°, 8.8°, 11.8°, 12.5°, 13.2°, 13.6°, 14.5°, 17.7°, 18.6°, 19.6°, 22.0°, 24.9°, 25.2°, and 25.9°2θ ± 0.2°2θ. Differential scanning calorimetry (DSC) analysis revealed endothermic peaks between 229°C and 235°C. The onset temperature was 229.4°C, and the maximum peak value was observed at 232.2°C.

[0122] Experiment 1: Stability Test

[0123] (S)-N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidine-3-yl)acetamide hydrochloride (amorphous form, test compound 1) prepared according to WO2012 / 115480 and (S)-N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidine-3-yl)acetamide hydrochloride in crystal form A (test compound 2) prepared in Example 7 were stored at 60 °C and 75% RH for 2 weeks. The amount of each test compound and the amount of deacetylated impurities were analyzed by HPLC to determine their respective HPLC purity. The results are shown in Table 1 below.

[0124]

[0125] HPLC purity

[0126]

[0127] As shown in Table 1 above, the crystal form A according to the present invention not only exhibits high purity initially, but also shows no significant change in HPLC purity and the amount of deacetylated impurities under conditions of 60°C and 75% RH. Conversely, the amorphous form according to the prior art not only exhibits a high content of deacetylated impurities initially, but also shows a significant decrease in HPLC purity and a significant increase in the amount of deacetylated impurities under conditions of 60°C and 75% RH. Therefore, the above results confirm that the crystal form according to the present invention has excellent stability.

Claims

1. Form A of the hydrochloride salt of the compound of Formula 1, having an XRPD pattern with peaks at 7.4°, 9.1°, 12.0°, 12.5°, 13.5°, 14.1°, 15.9°, 16.8°, 18.3°, 19.1°, 24.6°, 25.3° and 26.8° 2θ ± 0.2° 2θ, <Formula 1> 2. The crystalline form A of the hydrochloride salt of the compound of formula 1 according to claim 1, wherein the differential scanning calorimetry (DSC) thermogram thereof shows an endothermic peak between 229°C and 235°C.

3. A method for preparing Form A of the hydrochloride salt of the compound of Formula 1 according to claim 1 or 2, the method comprising (p) refluxing a reaction mixture obtained by adding hydrochloric acid to the compound of Formula 1 in an organic solvent; (q) cooling the reaction mixture obtained in step (p) to form a precipitate; and (r) separating the precipitate in step (q).

4. Form B of the hydrochloride salt of the compound of Formula 1, having an XRPD pattern at 7.3°, 8.8°, 11.8°, 12.5°, 13.2°, 13.6°, 14.5°, 17.7°, 18.6°, 19.6°, 22.0°, 24.9°, 25.2° and 25.9° 2θ ± 0.2° 2θ, <Formula 1> 5. The crystalline form B of the hydrochloride salt of the compound of formula 1 according to claim 4, wherein the differential scanning calorimetry (DSC) thermogram thereof shows an endothermic peak between 229°C and 235°C.

6. A method for preparing the crystalline form B of the hydrochloride salt of the compound of formula 1 according to claim 4 or 5, the method comprising exposing the crystalline form A of the hydrochloride salt of the compound of formula 1 according to claim 1 to a relative humidity condition of more than 40% to control its moisture content to more than about 3.5%.

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