Novel crystal form of lafamoline, and preparation method and application thereof

Abstract

The invention belongs to the technical field of medicinal chemistry, and relates to a novel crystal form of a lafamorin solvate and a preparation method thereof, in particular to a lafamorin solvate of a crystal form 3, a crystal form 4, a crystal form 5 and a crystal form 6, a preparation method of the lafamorin solvate and application of the lafamorin solvate as an intermediate for preparing amorphous lafamorin acetate.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical medicine and relates to a new crystal form of lafamulin solvate and a preparation method and use thereof. Background Art

[0002] Lafamlin is an innovative pleuromutilin antibiotic developed by Nabriva. It was approved in the United States on August 19, 2019, for the treatment of community-acquired bacterial pneumonia (CABP). It is the first antibiotic with an innovative mechanism of action approved by the FDA in nearly 20 years. The compound structure is shown below:

[0003]

[0004] However, to prepare substantially pure isomers / diastereomers of this compound, a process is needed that is amenable to industrial-scale use and avoids the use of expensive starting materials or time-consuming and labor-intensive purification steps. The process described in WO2008 / 113089 involves chromatographic purification of the compound prepared according to the various synthetic steps, and the final diastereomers are separated by chiral HPLC chromatography, which is not applicable on an industrial scale. CN103080083A describes the anhydrate form 1 and the n-butanol solvate crystalline form 2 of lafamulin free base.

[0005] There is also a need to develop new crystalline forms of lafamline that have excellent impurity removal capabilities, simple preparation methods, low cost, and ease of industrialization. The present invention relates to multiple new crystalline forms of lafamline free base that have excellent impurity removal capabilities and are easy to scale up for industrial production, thus having significant value for the purification, pharmaceutical research, and industrial production of lafamline. Summary of the Invention

[0006] In a first aspect, the present invention provides a crystalline form 3 of lafamulin acetonitrile solvate, characterized in that, using Cu-Ka radiation, X-ray powder diffraction (X-RPD) expressed in 2θ angles has characteristic peaks at 10.9±0.2°, 12.7±0.2°, 13.6±0.2°, 14.4±0.2°, 15.1±0.2°, 19.4±0.2°, and 22.3±0.2°;

[0007] Preferably, using Cu-Ka radiation, the X-ray powder diffraction expressed in 2θ angles has characteristic peaks at 9.3±0.2°, 10.0±0.2°, 10.9±0.2°, 12.7±0.2°, 13.6±0.2°, 14.4±0.2°, 15.1±0.2°, 19.4±0.2°, 22.3±0.2°, 24.3±0.2°, 25.8±0.2°, and 31.6±0.2°;

[0008] Further preferably, using Cu-Ka radiation, the X-ray powder diffraction expressed in 2θ angles has characteristic peaks at 9.3±0.2°, 10.0±0.2°, 10.9±0.2°, 12.7±0.2°, 13.6±0.2°, 14.4±0.2°, 15.1±0.2°, 16.0±0.2°, 19.4±0.2°, 20.2±0.2°, 21.4±0.2°, 22.3±0.2°, 24.3±0.2°, 25.8±0.2°, and 31.6±0.2°;

[0009] Most preferably, the crystalline form 3 has Figure 1 The X-ray powder diffraction pattern is shown.

[0010] A second aspect of the present invention provides a crystalline form 4 of lafamulin n-propanol solvate, characterized in that, using Cu-Ka radiation, X-ray powder diffraction (X-RPD) expressed in 2θ angles has characteristic peaks at 9.8±0.2°, 11.1±0.2°, 13.0±0.2°, 14.2±0.2°, 17.7±0.2°, 19.8±0.2°, and 22.4±0.2°;

[0011] Preferably, using Cu-Ka radiation, the X-ray powder diffraction pattern expressed in 2θ angles has characteristic peaks at 9.8±0.2°, 11.1±0.2°, 13.0±0.2°, 14.2±0.2°, 16.1±0.2°, 17.7±0.2°, 19.8±0.2°, 22.4±0.2°, 24.5±0.2°, and 25.2±0.2°;

[0012] Most preferably, the crystalline form 4 has Figure 2 The X-ray powder diffraction pattern is shown.

[0013] A third aspect of the present invention provides a crystalline form 5 of lafamulin n-pentanol solvate, characterized in that, using Cu-Ka radiation, X-ray powder diffraction (X-RPD) expressed in 2θ angles has characteristic peaks at 9.6±0.2°, 10.8±0.2°, 12.8±0.2°, 15.7±0.2°, 17.4±0.2°, 19.5±0.2°, and 21.9±0.2°;

[0014] Preferably, using Cu-Ka radiation, the X-ray powder diffraction pattern expressed in 2θ angles has characteristic peaks at 9.6±0.2°, 10.8±0.2°, 12.8±0.2°, 13.9±0.2°, 15.7±0.2°, 17.4±0.2°, 19.5±0.2°, 21.9±0.2°, and 24.1±0.2°;

[0015] Most preferably, the crystalline form 5 has Figure 3 The X-ray powder diffraction pattern is shown.

[0016] A fourth aspect of the present invention provides a crystalline form 6 of lafamulin isoamyl alcohol solvate, characterized in that, using Cu-Ka radiation, X-ray powder diffraction (X-RPD) expressed in 2θ angles has characteristic peaks at 9.5±0.2°, 10.8±0.2°, 11.8±0.2°, 12.8±0.2°, 15.8±0.2°, 17.3±0.2°, 19.3±0.2°, and 21.8±0.2°;

[0017] Preferably, using Cu-Ka radiation, the X-ray powder diffraction pattern expressed in 2θ angles has characteristic peaks at 9.5±0.2°, 10.8±0.2°, 11.8±0.2°, 12.9±0.2°, 13.8±0.2°, 15.8±0.2°, 17.3±0.2°, 19.3±0.2°, 21.8±0.2°, 22.5±0.2°, 22.8±0.2°, 24.1±0.2°, and 32.0±0.2°;

[0018] Most preferably, the crystalline form 6 has Figure 4 The X-ray powder diffraction pattern is shown.

[0019] In a fifth aspect, the present invention provides a method for preparing crystalline forms 3, 4, 5 and 6 of a lafamulin solvate, which comprises heating a mixture of crude lafamulin and a certain amount of a solvent, such as acetonitrile, n-propanol, n-pentanol or isopentanol, and a mixed solvent composed of other solvents, to 50 to 80° C. with stirring to dissolve, optionally filtering to remove insoluble matter, then slowly cooling to 5° C. to room temperature, stirring for 0.5 to 3 hours, then filtering with suction, and drying to obtain a crystalline form of the lafamulin solvate.

[0020] A sixth aspect of the present invention provides a method for preparing amorphous lafamulin acetate, wherein the novel crystalline form of the lafamulin solvate is used as a preparation intermediate.

[0021] The new crystalline forms of the lafamulin solvate disclosed herein have excellent impurity removal properties and are easily scalable for industrial production, significantly contributing to the purification, pharmaceutical research, and industrial production of lafamulin. In particular, the crystalline forms 4 and 5 provided herein exhibit even better impurity removal properties and are simple to prepare. DETAILED DESCRIPTION

[0022] The following further details the above content of the present invention through specific embodiments, but this should not be construed as limiting the subject matter of the present invention. All technical solutions implemented based on the above content of the present invention fall within the scope of the present invention. The present invention provides a general and / or specific description of the materials and test methods used in the experiments.

[0023] As used herein, unless otherwise specified, the operations performed in the present invention are performed under conventional room temperature conditions in the art. The room temperature has a technical meaning well known in the art, generally referring to 20-35°C, preferably 20-30°C, and more preferably 25-30°C.

[0024] As used herein, the term "about" refers to a numerical value, including, for example, integers, fractions, and percentages, whether or not explicitly indicated. Each number in the specification or claims can be considered to be modified by the term "about." The term "about" generally refers to a numerical range that one of ordinary skill in the art considers to be equivalent to the value (e.g., having the same function or result), such as ± 5-10% of the range. When terms such as at least and approximately precede a numerical value or range list, these terms modify all values ​​or ranges provided in the list.

[0025] The reagents used in the present invention are all conventional reagents and can be purchased on the market. The starting materials and reactants used can be prepared by existing technologies or disclosed existing literature, or can be purchased on the market.

[0026] As used herein, unless otherwise specified, the amounts of the solvents and inorganic reagents used are conventional amounts used in the reaction and can be determined by those skilled in the art based on existing techniques.

[0027] In a first aspect, the present invention provides a crystalline form 3 of lafamulin acetonitrile solvate, which uses Cu-Ka radiation and has characteristic peaks in X-ray powder diffraction (X-RPD) expressed in 2θ angles at 10.9±0.2°, 12.7±0.2°, 13.6±0.2°, 14.4±0.2°, 15.1±0.2°, 19.4±0.2°, and 22.3±0.2°.

[0028] In some preferred embodiments, the crystalline form 3 of the lafamulin acetonitrile solvate of the present invention uses Cu-Ka radiation, and the X-ray powder diffraction expressed in 2θ angles has characteristic peaks at 9.3±0.2°, 10.0±0.2°, 10.9±0.2°, 12.7±0.2°, 13.6±0.2°, 14.4±0.2°, 15.1±0.2°, 19.4±0.2°, 22.3±0.2°, 24.3±0.2°, 25.8±0.2°, and 31.6±0.2°.

[0029] In some preferred embodiments, the crystalline form 3 of the lafamulin acetonitrile solvate of the present invention has the following characteristics: Figure 1 The X-ray powder diffraction pattern is shown.

[0030] In some preferred embodiments, the differential scanning calorimetry (DSC) spectrum of the crystalline form 3 of the lafamulin acetonitrile solvate of the present invention respectively shows endothermic peaks in the range of 77-84°C, 84-99°C, and 150-169°C. Preferably, the peak values ​​of the endothermic peaks of the DSC spectrum of the crystalline form 3 appear at 81.7±2°C, 88.7±2°C, and 158.5±2°C, respectively. More preferably, the crystalline form 3 has the following characteristics: Figure 5 The DSC spectrum is shown.

[0031] In some preferred embodiments, the thermogravimetric analysis (TGA) spectrum of the crystalline form 3 of the rafamulin acetonitrile solvate of the present invention shows a weight loss in the range of 36-124°C, and the mass fraction of the weight loss is 5.7%. Preferably, the crystalline form 3 has the following characteristics: Figure 5 TGA spectrum shown.

[0032] The second aspect of the present invention provides a crystalline form 4 of lafamulin n-propanol solvate, which uses Cu-Ka radiation and has characteristic peaks in X-ray powder diffraction (X-RPD) expressed in 2θ angles at 9.8±0.2°, 11.1±0.2°, 13.0±0.2°, 14.2±0.2°, 17.7±0.2°, 19.8±0.2°, and 22.4±0.2°.

[0033] In some preferred embodiments, the crystalline form 4 of the lafamulin n-propanol solvate of the present invention uses Cu-Ka radiation, and the X-ray powder diffraction expressed in 2θ angles has characteristic peaks at 9.8±0.2°, 11.1±0.2°, 13.0±0.2°, 14.2±0.2°, 16.1±0.2°, 17.7±0.2°, 19.8±0.2°, 22.4±0.2°, 24.5±0.2°, and 25.2±0.2°.

[0034] In some preferred embodiments, the lafamulin n-propanol solvate crystalline form 4 of the present invention has the following characteristics: Figure 2 The X-ray powder diffraction pattern is shown.

[0035] In some preferred embodiments, the differential scanning calorimetry (DSC) spectrum of the lafamulin n-propanol solvate crystalline form 4 of the present invention shows endothermic peaks in the ranges of 87-107°C, 107-124°C, and 150-169°C, respectively. Preferably, the peaks of the endothermic peaks of the DSC spectrum of the crystalline form 4 appear at 99.3±2°C, 113.0±2°C, and 158.3±2°C, respectively. More preferably, the crystalline form 4 has the following properties: Figure 6 The DSC spectrum is shown.

[0036] In some preferred embodiments, the thermogravimetric analysis (TGA) spectrum of the crystalline form 4 of the lafamulin n-pentanol solvate of the present invention shows a weight loss in the range of 36-124°C, and the mass fraction of the weight loss is 9.5%. Preferably, the crystalline form 4 has the following characteristics: Figure 6 TGA spectrum shown.

[0037] The third aspect of the present invention provides a crystalline form 5 of lafamulin n-pentanol solvate, which uses Cu-Ka radiation and has characteristic peaks in X-ray powder diffraction (X-RPD) expressed in 2θ angles at 9.6±0.2°, 10.8±0.2°, 12.8±0.2°, 15.7±0.2°, 17.4±0.2°, 19.5±0.2°, and 21.9±0.2°.

[0038] In some preferred embodiments, the crystalline form 5 of the lafamulin n-pentanol solvate of the present invention uses Cu-Ka radiation, and the X-ray powder diffraction expressed in 2θ angles has characteristic peaks at 9.6±0.2°, 10.8±0.2°, 12.8±0.2°, 13.9±0.2°, 15.7±0.2°, 17.4±0.2°, 19.5±0.2°, 21.9±0.2°, and 24.1±0.2°.

[0039] In some preferred embodiments, the crystalline form 5 of the lafamulin n-pentanol solvate of the present invention has the following characteristics: Figure 3 The X-ray powder diffraction pattern is shown.

[0040] In some embodiments, the differential scanning calorimetry (DSC) spectrum of the lafamulin n-pentanol solvate crystalline form 5 of the present invention exhibits endothermic peaks in the range of 85-122°C and 123-165°C, respectively. Preferably, the peak values ​​of the endothermic peaks of the DSC spectrum of the crystalline form 5 appear at 104.8±2°C and 154.4±2°C, respectively. More preferably, the crystalline form 5 has the following properties: Figure 7 The DSC spectrum is shown.

[0041] In some preferred embodiments, the thermogravimetric analysis (TGA) spectrum of the lafamulin n-pentanol solvate crystal form 5 of the present invention shows a mass fraction of 10.7% weight loss in the range of 36-122°C, and a mass fraction of 1.6% weight loss in the range of 122-165°C. Preferably, the crystal form 5 has the following characteristics: Figure 7 TGA spectrum shown.

[0042] The fourth aspect of the present invention provides a crystalline form 6 of lafamulin isoamyl alcohol solvate, which uses Cu-Ka radiation and has characteristic peaks in X-ray powder diffraction (X-RPD) expressed in 2θ angles at 9.5±0.2°, 10.8±0.2°, 11.8±0.2°, 12.8±0.2°, 15.8±0.2°, 17.3±0.2°, 19.3±0.2°, and 21.8±0.2°.

[0043] In some preferred embodiments, the crystalline form 6 of the lafamulin isoamyl alcohol solvate of the present invention uses Cu-Ka radiation, and the X-ray powder diffraction expressed in 2θ angles has characteristic peaks at 9.5±0.2°, 10.8±0.2°, 11.8±0.2°, 12.9±0.2°, 13.8±0.2°, 15.8±0.2°, 17.3±0.2°, 19.3±0.2°, 21.8±0.2°, 22.5±0.2°, 22.8±0.2°, 24.1±0.2°, and 32.0±0.2°.

[0044] In some preferred embodiments, the crystalline form 6 of the lafamulin isoamyl alcohol solvate of the present invention has the following characteristics: Figure 4 The X-ray powder diffraction pattern is shown.

[0045] In some embodiments, the crystalline form 6 of the lafamulin isoamyl alcohol solvate of the present invention has endothermic peaks in the range of 148 to 168° C. in its differential scanning calorimetry (DSC) spectrum. Preferably, the peak of the endothermic peak of the DSC spectrum of the crystalline form 6 appears at 157.5±2° C. More preferably, the crystalline form 6 has the following characteristics: Figure 8 The DSC spectrum is shown.

[0046] In some embodiments, the thermogravimetric analysis (TGA) spectrum of the crystalline form 6 of the lafamulin isoamyl alcohol solvate of the present invention does not show significant weight loss before melting. Preferably, the crystalline form 6 has the following characteristics: Figure 8 TGA spectrum shown.

[0047] In some embodiments, the method for preparing the crystalline form 3 of lafamulin acetonitrile solvate comprises stirring and heating a mixture of crude lafamulin and solvent acetonitrile to 60-80° C., filtering to remove insoluble matter, then slowly cooling to 15-25° C. and stirring for 1-3 hours, then filtering and drying.

[0048] In some embodiments, the method for preparing the crystalline form 4 of lafamulin n-propanol solvate comprises stirring and heating a mixture of crude lafamulin and solvent n-propanol to 50-70° C., filtering to remove insoluble matter, then slowly cooling to 13-25° C. and stirring for 1-3 hours, then filtering and drying.

[0049] In some embodiments, the method for preparing the crystalline form 5 of lafamulin n-pentanol solvate comprises stirring and heating a mixture of crude lafamulin and solvent n-pentanol to 60-80° C., filtering to remove insoluble matter, then slowly cooling to 5-15° C. and stirring for 1-3 hours, then filtering and drying.

[0050] In some embodiments, the method for preparing the crystalline form 6 of lafamulin isoamyl alcohol solvate comprises stirring and heating a mixture of crude lafamulin and solvent isoamyl alcohol to 60-80° C., filtering to remove insoluble matter, then slowly cooling to 10-20° C. and stirring for 0.5-2 hours, then filtering and drying.

[0051] In some embodiments, the ratio of the solvent (such as but not limited to acetonitrile, n-propanol, n-pentanol and isoamyl alcohol) to crude lafamulin is 2 to 50 mL / g, preferably 3 to 20 mL / g, more preferably 5-10 mL / g.

[0052] The new crystalline form of the lafamulin solvate of the present invention can be used to prepare amorphous lafamulin acetate. The method for preparing amorphous lafamulin acetate comprises adding purified water and a certain amount of acetic acid to any of the crystalline forms 3, 4, 5, and 6 of the lafamulin solvate to form a salt, and freeze-drying the resulting clear solution. The freeze-drying conditions are as follows:

[0053] The first stage: cool down to -35~-55℃ within 15~45 minutes; keep at -35~-55℃ for about 1~3 hours; reduce pressure and evacuate to 10~25Pa at -35~-55℃ for 10~30 minutes;

[0054] The second stage: heating to 0-10°C for 50-70 minutes at 10-25 Pa; maintaining the temperature at 0-10°C and pressure at 10-25 Pa for 10-20 hours;

[0055] The third stage: reduce the pressure and evacuate to 3-7 Pa within 50-70 minutes, and at the same time raise the temperature to 30-50°C; maintain the temperature at 30-50°C and the pressure at 4-6 Pa for 4-7 hours.

[0056] In some embodiments, the temperature of the first stage in the method is preferably -35 to -50°C, more preferably -38 to -45°C. In some embodiments, the cooling time of the first stage in the method is preferably 25 to 35 minutes. In some embodiments, the temperature of the second stage in the method is preferably 0 to -5°C, more preferably about -2°C. In some embodiments, the heating time of the second stage in the method is preferably 55 to 65 minutes. In some embodiments, the pressure of the third stage in the method is reduced to 4 to 6 Pa, more preferably about 5 Pa. In some embodiments, the temperature of the third stage in the method is preferably 35 to 45°C, more preferably about 40°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The figure is the X-ray powder diffraction pattern of rafamulin solvate form 3.

[0058] Figure 2 The figure is the X-ray powder diffraction pattern of rafamulin solvate form 4.

[0059] Figure 3 This is the X-ray powder diffraction pattern of rafamulin solvate form 5.

[0060] Figure 4 This is the X-ray powder diffraction pattern of rafamulin solvate form 6.

[0061] Figure 5 This is the TGA-DSC thermogram of lafamulin solvate Form 3.

[0062] Figure 6 This is the TGA-DSC thermogram of lafamulin solvate form 4.

[0063] Figure 7 This is the TGA-DSC thermogram of lafamulin solvate Form 5.

[0064] Figure 8 This is the TGA-DSC thermogram of lafamulin solvate Form 6.

[0065] Figure 9 The X-ray powder diffraction pattern of amorphous rafamulin acetate.

[0066] Example

[0067] X-ray powder diffraction (XRPD)

[0068] Solid samples were analyzed using a Malvern Panalytical Aeris X-ray desktop diffractometer. An appropriate amount of sample powder was placed in a groove in the sample holder and pressed into a flat and dense surface. The XRPD measurement parameters are shown in Table 1.

[0069] Table 1 XRPD test parameters

[0070]

[0071]

[0072] Simultaneous thermal analyzer

[0073] Solids were analyzed using a Mettler Toledo simultaneous thermal analyzer (TGA) coupled with thermogravimetric and differential scanning calorimetry (DSC). An appropriate amount of the sample was placed in a crucible using a small spoon, spread evenly, and weighed. The sample was heated according to the parameters listed in Table 2, and the data was analyzed using STARe.

[0074] Table 2 TGA-DSC analysis method parameters

[0075]

[0076] The product purity and impurity content were determined by HPLC, as shown in Table 3.

[0077] Table 3 HPLC related parameters

[0078]

[0079]

[0080] Gradient elution method:

[0081]

[0082] Note: Add a trapping column between the injector and the mixer: Ghost trap DS (7.6*30mm)

[0083] Solution preparation: Weigh about 20 mg of lafamulin sample and add solvent (acetonitrile: water = 50:50) to 10 mL. After the sample is completely dissolved, load it into liquid chromatography and determine it using the area normalization method.

[0084] Example 1 Preparation of Lafamulin Solvate Form 3

[0085] Take 1.00g of rafamulin in a reaction flask, add 6.0mL of acetonitrile, heat in a water bath to 65-75℃, stir until the solid dissolves, and remove insoluble matter through a 0.45um filter to obtain a clear liquid. Slowly cool to 20℃ in about 4 hours, maintain 20℃ and stir for 2 hours, then filter. The solid is vacuum dried at 40℃ for 4 hours to obtain 0.85g of rafamulin form 3, with a molar yield of 78.6%. The X-ray powder diffraction pattern of the obtained rafamulin form 3 is the same as Figure 1 same.

[0086] Example 2 Preparation of Lafamulin Solvate Form 4

[0087] Method A:

[0088] Take 101.2 mg of rafamulin and add it to a sample bottle, add 1.0 mL of n-propanol, heat it in a water bath to 55-65 ° C, stir until the solid is dissolved, and remove the insoluble matter through a 0.45 μm filter to obtain a clear liquid. The above clear liquid is cooled to 15-20 ° C within 4 hours, and a large amount of solid is precipitated. After stirring at 15-20 ° C for 2 hours, it is filtered. The solid is dried at room temperature for 15 hours to obtain 54.5 mg of rafamulin crystal form 4 with a molar yield of 48.2%. The X-ray powder diffraction pattern of the obtained rafamulin crystal form 4 is shown in Figure 2 , TGA-DSC spectrum see Figure 7 The TGA weight loss was 9.5%, and the theoretical mass fraction of 1 equivalent of n-propanol was 9.6%. It was speculated that Form 4 was a n-propanol solvate.

[0089] Method B:

[0090] Take 6.00g of rafamulin and add it to a sample bottle, add 36mL of n-propanol, heat in a water bath to 65-75℃, stir until the solid dissolves, and remove insoluble matter through a 0.45um filter to obtain a clear liquid. Slowly cool the above clear liquid to 65℃ and add 10mg of crystal seed of Form 4, and slowly cool it to 10℃ in about 4h. After stirring at 10℃ for 2h, filter with suction. Dry the solid in a vacuum at 40℃ for 12h to obtain 5.25g of rafamulin Form 4 with a molar yield of 78.3%. The X-ray powder diffraction pattern of the obtained rafamulin Form 4 is shown in Figure 2 same.

[0091] Example 3 Preparation of Lafamulin Form 5

[0092] Method A:

[0093] Take 102.1 mg of rafamulin and add it to a sample bottle, add 2 mL of n-pentanol, heat in a water bath to 65-75 ° C, stir until the solid is dissolved, and remove the insoluble matter through a 0.45 μm filter to obtain a clear liquid. The above clear liquid is slowly cooled to 15 ° C to precipitate a large amount of solid. After stirring at 15 ° C for 1 hour, filter it with suction. Dry the solid at room temperature for 15 hours to obtain 50.3 mg of rafamulin crystal form 5 with a molar yield of 44.1%. The X-ray powder diffraction pattern of the obtained rafamulin crystal form 5 is shown in Figure 3 , TGA-DSC spectrum see Figure 7 The TGA weight loss was 12.3%, and the theoretical mass fraction of 1 equivalent of n-pentanol was 13.4%. It was speculated that Form 5 was a n-pentanol solvate.

[0094] Method B:

[0095] Take 2.00g of rafamulin and add it to a sample bottle, add 12mL of n-pentanol, heat in a water bath to 65-75℃, stir until the solid is dissolved, and remove the insoluble matter through a 0.45um filter to obtain a clear liquid. Cool the above clear liquid to 50℃ to precipitate the solid, and slowly cool it to 10℃ within about 4h. After stirring at 10℃ for 2h, filter it with suction. Dry the solid in a vacuum at 40℃ for 12h to obtain 1.75g ​​of rafamulin form 5 with a molar yield of 74.6%. The X-ray powder diffraction pattern of the obtained rafamulin form 5 is shown in Figure 3 same.

[0096] Example 4 Preparation of Lafamlin Form 6

[0097] 100.3 mg of rafamulin was added to a sample bottle, 0.6 mL of isoamyl alcohol was added, and the mixture was heated in a water bath to 75°C. Stirring was carried out until the solid dissolved. Insoluble matter was removed through a 0.45 μm filter to obtain a clear liquid. The clear liquid was slowly cooled to 15°C over approximately 4 hours to precipitate a large amount of solid. After stirring at 15°C for 1 hour, the mixture was filtered. The solid was air-dried at room temperature for 15 hours to obtain 88.5 mg of rafamulin Form 6 with a molar yield of 75.2%. The X-ray powder diffraction pattern of the obtained rafamulin Form 6 is shown in FIG. Figure 4 , TGA-DSC spectrum see Figure 8 .

[0098] Example 5 Comparison of impurity removal ability of different crystalline forms of Lafamlin

[0099] Using the same crude rafamulin product as a raw material, the crude product was refined by cooling and crystallization, and the amount of solvent used was 6 ml / g. Form 3 (Example 1 Method B), Form 4 (Example 2 Method B), Form 5 (Example 3 Method B), and Form 6 (Example 4) were prepared. The n-butanol solvate Form 2 was prepared by the method described in Step B of Example 4 of Patent CN103080083A. The product purity and impurity content were determined by high performance liquid chromatography using the area normalization method. The results are shown in Table 4 below. As shown in Table 4, Form 5 has a better impurity removal effect than Form 2 of the prior art, and the product purity is significantly higher, which is beneficial for the purification of rafamulin free base.

[0100] Table 4 Product purity and impurity content

[0101]

[0102]

[0103] Example 6 Preparation of Lafamylline Acetate Amorphous Form

[0104] Using Form 4 of Lafamylline n-propanol solvate as the starting material:

[0105] 1.003 g of purified lafamulin (form 4) was added to a sample bottle, 10 mL of purified water was added, 0.106 g of glacial acetic acid was added with stirring, and the mixture was heated to 45°C and stirred to dissolve. Insoluble matter was removed by filtering through a 0.45 μm filter to obtain a clear solution. The clear solution was placed in a freeze dryer and freeze-dried to obtain 0.985 g of amorphous lafamulin acetate. The X-ray powder diffraction pattern of the obtained lafamulin acetate is shown in FIG. Figure 9 The freeze-drying conditions are as follows: cooling to -40°C in 30 minutes; maintaining -40°C for about 1 hour; maintaining -40°C under reduced pressure and vacuuming to 10-25 Pa for 20 minutes; heating to -2°C under 10-25 Pa for 60 minutes; maintaining -2°C, 10-25 Pa for 15 hours; reducing pressure and vacuuming to 5 Pa for 60 minutes while heating to 40°C; maintaining 40°C, 5 Pa for 6 hours.

[0106] Starting from the crystal form 5 of lafamulin n-pentanol solvate:

[0107] 1.000 g of purified lafamulin (form 5) was added to a sample bottle, 10 mL of purified water was added, 0.105 g of glacial acetic acid was added under stirring, and the mixture was heated to 45°C and stirred to dissolve. Insoluble matter was removed by filtering through a 0.45 μm filter to obtain a clear solution. The clear solution was placed in a freeze dryer and freeze-dried to obtain 0.970 g of amorphous lafamulin acetate. The X-ray powder diffraction pattern of the obtained lafamulin acetate was the same as Figure 9 The freeze-drying conditions are as follows: cooling to -40°C over 30 minutes; maintaining -40°C for approximately 1 hour; maintaining -40°C under reduced pressure and vacuuming to 10-25 Pa for 20 minutes; heating to -2°C under 10-25 Pa for 60 minutes; maintaining -2°C at 10-25 Pa for 15 hours; heating to 5 Pa under reduced pressure and vacuuming to 5 Pa over 60 minutes while simultaneously heating to 40°C; maintaining 40°C at 5 Pa for 6 hours.

Claims

1. A crystalline form 3 of lafamulin acetonitrile solvate, characterized in that Using Cu-Ka radiation, X-ray powder diffraction (X-RPD) expressed in 2θ angles showed characteristic peaks at 10.9 ± 0.2°, 12.7 ± 0.2°, 13.6 ± 0.2°, 14.4 ± 0.2°, 15.1 ± 0.2°, 19.4 ± 0.2°, and 22.3 ± 0.2°; Preferably, using Cu-Ka radiation, the X-ray powder diffraction expressed in 2θ angles has characteristic peaks at 9.3±0.2°, 10.0±0.2°, 10.9±0.2°, 12.7±0.2°, 13.6±0.2°, 14.4±0.2°, 15.1±0.2°, 19.4±0.2°, 22.3±0.2°, 24.3±0.2°, 25.8±0.2°, and 31.6±0.2°; Further preferably, using Cu-Ka radiation, the X-ray powder diffraction expressed in 2θ angles has characteristic peaks at 9.3±0.2°, 10.0±0.2°, 10.9±0.2°, 12.7±0.2°, 13.6±0.2°, 14.4±0.2°, 15.1±0.2°, 16.0±0.2°, 19.4±0.2°, 20.2±0.2°, 21.4±0.2°, 22.3±0.2°, 24.3±0.2°, 25.8±0.2°, and 31.6±0.2°; Most preferably, the crystalline form 3 has an X-ray powder diffraction pattern as shown in FIG1 .

2. A crystalline form 4 of lafamulin n-propanol solvate, characterized in that: Using Cu-Ka radiation, X-ray powder diffraction (X-RPD) expressed in 2θ angles showed characteristic peaks at 9.8 ± 0.2°, 11.1 ± 0.2°, 13.0 ± 0.2°, 14.2 ± 0.2°, 17.7 ± 0.2°, 19.8 ± 0.2°, and 22.4 ± 0.2°; Preferably, using Cu-Ka radiation, the X-ray powder diffraction pattern expressed in 2θ angles has characteristic peaks at 9.8±0.2°, 11.1±0.2°, 13.0±0.2°, 14.2±0.2°, 16.1±0.2°, 17.7±0.2°, 19.8±0.2°, 22.4±0.2°, 24.5±0.2°, and 25.2±0.2°; Most preferably, the crystalline form 4 has an X-ray powder diffraction pattern as shown in FIG2 .

3. A crystalline form 5 of lafamulin n-pentanol solvate, characterized in that: Using Cu-Ka radiation, X-ray powder diffraction (X-RPD) expressed in 2θ angles showed characteristic peaks at 9.6 ± 0.2°, 10.8 ± 0.2°, 12.8 ± 0.2°, 15.7 ± 0.2°, 17.4 ± 0.2°, 19.5 ± 0.2°, and 21.9 ± 0.2°; Preferably, using Cu-Ka radiation, the X-ray powder diffraction pattern expressed in 2θ angles has characteristic peaks at 9.6±0.2°, 10.8±0.2°, 12.8±0.2°, 13.9±0.2°, 15.7±0.2°, 17.4±0.2°, 19.5±0.2°, 21.9±0.2°, and 24.1±0.2°; Most preferably, the crystalline form 5 has an X-ray powder diffraction pattern as shown in FIG3 .

4. A crystalline form 6 of lafamulin isoamyl alcohol solvate, characterized in that: Using Cu-Ka radiation, X-ray powder diffraction (X-RPD) expressed in 2θ angles showed characteristic peaks at 9.5 ± 0.2°, 10.8 ± 0.2°, 11.8 ± 0.2°, 12.8 ± 0.2°, 15.8 ± 0.2°, 17.3 ± 0.2°, 19.3 ± 0.2°, and 21.8 ± 0.2°; Preferably, using Cu-Ka radiation, the X-ray powder diffraction pattern expressed in 2θ angles has characteristic peaks at 9.5±0.2°, 10.8±0.2°, 11.8±0.2°, 12.9±0.2°, 13.8±0.2°, 15.8±0.2°, 17.3±0.2°, 19.3±0.2°, 21.8±0.2°, 22.5±0.2°, 22.8±0.2°, 24.1±0.2°, and 32.0±0.2°; Most preferably, the crystalline form 6 has an X-ray powder diffraction pattern as shown in FIG4 .

5. A method for preparing the crystalline form 3 of lafamulin acetonitrile solvate according to claim 1, comprising heating a mixture of crude lafamulin and acetonitrile solvent to 60-80° C. with stirring, filtering to remove insoluble matter, then slowly cooling to 15-25° C. and stirring for 1-3 hours, then filtering with suction, and drying.

6. A method for preparing the crystalline form 4 of lafamulin n-propanol solvate according to claim 2, comprising: stirring and heating a mixture of crude lafamulin and solvent n-propanol to 50-70°C, filtering to remove insoluble matter, then slowly cooling to 13-25°C, stirring for 1-3 hours, then filtering with suction, and drying.

7. A method for preparing the crystalline form 5 of lafamulin n-pentanol solvate according to claim 3, comprising: stirring and heating a mixture of crude lafamulin and solvent n-pentanol to 60-80°C, filtering to remove insoluble matter, then slowly cooling to 5-15°C, stirring for 1-3 hours, then filtering with suction, and drying.

8. A method for preparing the crystalline form 6 of lafamulin isoamyl alcohol solvate according to claim 4, comprising: stirring and heating a mixture of crude lafamulin and isoamyl alcohol solvent to 60-80°C, filtering to remove insoluble matter, then slowly cooling to 10-20°C and stirring for 0.5-2 hours, then filtering with suction, and drying.

9. The process according to claims 5 to 8, wherein the ratio of the solvent to the crude rafamulin is 2 to 50 mL / g, preferably 3 to 20 mL / g, more preferably 5 to 10 mL / g.

10. A method for preparing amorphous rafamulin acetate, comprising adding purified water and a certain amount of acetic acid to the rafamulin solvate of any one of claims 1 to 4 as a preparation intermediate, reacting to form a salt to obtain a clear solution, and freeze-drying the solution. The freeze-drying conditions are: The first stage: cool down to -35~-55℃ within 15~45 minutes; keep at -35~-55℃ for about 1~3 hours; reduce pressure and evacuate to 10~25Pa at -35~-55℃ for 10~30 minutes; The second stage: heating to 0-10°C for 50-70 minutes at 10-25 Pa; maintaining the temperature at 0-10°C and pressure at 10-25 Pa for 10-20 hours; The third stage: reduce the pressure and evacuate to 3-7 Pa within 50-70 minutes, and at the same time raise the temperature to 30-50°C; maintain the temperature at 30-50°C and the pressure at 4-6 Pa for 4-7 hours.

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