High-purity compound production method and purification method

Abstract

The present invention provides an effective production method and / or purification method for a high-yield and high-purity (R)-11-[[-[(diethylamino)methyl]-1-piperidinyl]-acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, said compound not containing impurities, particularly 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one.

Description

Method for producing and purifying high-purity compounds

[0001] The present invention relates to a method for producing and purifying highly purified (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (hereinafter sometimes referred to as "AFDX0250") or a salt thereof. The present invention also relates to highly purified AFDX0250 or a salt thereof, and to a pharmaceutical composition containing highly purified AFDX0250 or a salt thereof, which is substantially free of impurities such as 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (hereinafter sometimes referred to as "Compound 1").

[0002] AFDX0250 is (+)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one, has the structure shown below, and is known to be useful in the treatment of eye diseases such as glaucoma, ocular hypertension, and myopia (Patent Documents 1 and 2).

[0003] Methods for producing AFDX0250 are disclosed in Non-Patent Document 1 and Patent Document 3. Non-Patent Document 1 discloses the production of AFDX0250 by reacting 11-(chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one with (-)-2-[(diethylamino)methyl]piperidine in acetonitrile in the presence of sodium carbonate, following a general procedure for reaction. Patent Document 3 also discloses a method for producing AFDX0250 by reacting 11-(chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one with (-)-2-[(diethylamino)methyl]piperidine in acetonitrile in the presence of sodium carbonate, following an example of reaction, but the yield is shown to be low at 59%.

[0004] In order to manufacture and sell AFDX0250 as a pharmaceutical product, it is important to produce AFDX0250 in high yield and to purify it effectively, and to remove impurities from the crude product and produce it at high purity to prevent undesirable effects.

[0005] International Publication No. 93 / 18772 Pamphlet International Publication No. 2022 / 030489 Pamphlet Japanese Patent Application Laid-Open No. 60-215683

[0006] Wolfnard W. Engel et al., J. Med. Chem., 1989, 32(8), 1718-1724

[0007] Pharmaceuticals require high purity to meet approval standards for quality and purity. For example, impurities generated during pharmaceutical production and / or storage can lead to problems such as reduced therapeutic efficacy and undesirable side effects. Furthermore, low yields of compounds useful as pharmaceutical active ingredients make mass synthesis or industrial production of the compounds difficult, resulting in high pharmaceutical development costs. As mentioned above, Non-Patent Document 1 and Patent Document 3 disclose methods for producing AFDX0250, but the yield of the produced AFDX0250 is low. Therefore, there is room for improvement in conventional methods for producing AFDX0250 for use as a pharmaceutical.

[0008] Furthermore, during the development stage of a pharmaceutical composition containing AFDX0250 or a salt thereof, the present inventors discovered that 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one contained in the produced AFDX0250 was positive in the Ames test, and considered it desirable to remove such a compound from the viewpoint of the occurrence of side effects.

[0009] Therefore, an objective of the present invention is to provide an effective method for producing and / or purifying AFDX0250 or a salt thereof in high yield and high purity, free of impurities, particularly 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one. Another objective of the present invention is to provide AFDX0250 or a salt thereof in high yield and high purity, substantially free of impurities, and a highly safe pharmaceutical composition containing high-purity AFDX0250.

[0010] As a result of intensive investigations aimed at solving the above problems, the present inventors have found specific conditions for a method for producing AFDX0250 or a salt thereof in high yield and with high purity from 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof and (R)-2-(diethylamino)methylpiperidine or a salt thereof, as well as specific conditions for crystallization for purifying AFDX0250 or a salt thereof to a high purity. More specifically, the present inventors have discovered that AFDX0250 or a salt thereof can be produced in high yield and purity by reacting 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof with (R)-2-(diethylamino)methylpiperidine or a salt thereof in the presence of an alkali metal iodide under basic conditions in an organic solvent containing acetonitrile in an amount of 15 to 50 mL per gram of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, and that the resulting crude AFDX0250 can be crystallized to high purity by appropriately adjusting the solvent and temperature, thereby completing the present invention.

[0011] Specifically, the present invention provides the following: [Item 1] A method for producing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, comprising a step of reacting 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof with (R)-2-(diethylamino)methylpiperidine or a salt thereof in an organic solvent in the presence of an alkali metal iodide under basic conditions, wherein the organic solvent contains 15 to 50 mL of acetonitrile per 1 g of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. [Item 2] The production method according to Item 1, wherein the organic solvent is 15 to 50 mL of acetonitrile per 1 g of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. [Item 3] The production method according to Item 1 or 2, which comprises a step of adding water and an acid to the reaction mixture to adjust the pH, and then extracting with an organic solvent. [Item 4] The production method according to Item 3, wherein extraction with an organic solvent is carried out two or more times. [Item 5] The production method according to Item 3 or 4, wherein the organic solvent is ethyl acetate. [Item 6] A method for producing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, comprising a step of reacting 11-(2-iodoacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof with (R)-2-(diethylamino)methylpiperidine or a salt thereof in an organic solvent under basic conditions.[Item 7] A method for purifying (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, comprising a step of crystallizing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof in a mixed solution of 1-propanol and water. [Item 8] A method for purifying (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, comprising a step of treating (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof with activated carbon in an alcoholic solvent. [Item 9] A method for purifying (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, comprising a step of recrystallizing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof in a mixed solution of an alcohol solvent and a ketone solvent. [Item 10] (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof having a purity of 95% or more. [Item 11] (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, having an impurity content of less than 5%.[Item 12] A pharmaceutical composition comprising (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, wherein the content of impurities derived from (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof is less than 5% relative to the amount of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. [Item 13] The pharmaceutical composition according to Item 12, wherein the impurity content is less than 1%. [Item 14] A pharmaceutical composition comprising (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, wherein the pharmaceutical composition is substantially free of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. [Item 15] The pharmaceutical composition of Item 14, wherein the content of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof is less than 1000 ppm relative to the amount of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. [Item 16] The pharmaceutical composition of Item 14 or 15, further comprising substantially no 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. [Item 17] The pharmaceutical composition according to Item 16, wherein the content of 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof is less than 1000 ppm.

[0012] It should be noted that any two or more of the configurations in [Item 1] to [Item 17] above can be selected and combined.

[0013] The present invention further provides the following: [Item 18] The pharmaceutical composition according to any one of Items 12 to 17, which is an eye drop. [Item 19] The pharmaceutical composition according to any one of Items 12 to 18, for treating glaucoma, ocular hypertension, or myopia.

[0014] The production and purification methods of the present invention enable the production of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof in higher yield and higher purity than known methods. Furthermore, the content of impurities such as 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one can be reduced. Furthermore, the present invention can provide highly purified (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, and a pharmaceutical composition comprising highly purified (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0015] The following shows the properties of AFDX0250 samples (powder and DMSO solution) containing each solvent (ethanol (EtOH), 1-propanol (1-PrOH), and N-methylpyrrolidone (NMP)) before and after activated carbon treatment with Shirasagi A (0.05 w / w, 0.10 w / w, and 0.15 w / w) and Shirasagi P (0.10 w / w and 0.15 w / w). Note that samples containing NMP as a solvent were not prepared using Shirasagi A (0.15 w / w) and Shirasagi P (0.10 w / w and 0.15 w / w). The recrystallization step was carried out using ethanol as the alcoholic solvent and acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), or n-heptane as the antisolvent, with total solvent amounts of 10 v / w (ratio 1:3) and 20 v / w (ratio 1:1), respectively. The properties of the dried product and DMSO solution obtained before purification are shown. The recrystallization step was carried out using 1-propanol as the alcoholic solvent and acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), or n-heptane as the antisolvent, with total solvent amounts of 10 v / w (ratio 1:3) and 20 v / w (ratio 1:1), respectively. The properties of the dried product and DMSO solution obtained before purification are shown.

[0016] The present invention will be described in detail below.

[0017] The present invention provides a method for producing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, which comprises a step of reacting 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof with (R)-2-(diethylamino)methylpiperidine or a salt thereof in an organic solvent containing acetonitrile, preferably acetonitrile, in the presence of an alkali metal iodide under basic conditions. In this step, 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, (R)-2-(diethylamino)methylpiperidine or a salt thereof, an organic solvent containing acetonitrile, preferably acetonitrile, an alkali metal iodide, and a base are mixed, heated and stirred, and then concentrated to obtain a reaction mixture.

[0018] As the raw materials in this step, 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof and (R)-2-(diethylamino)methylpiperidine or a salt thereof, commercially available products may be used, or products produced by known methods may be used.

[0019] The "organic solvent" in this step contains acetonitrile, and preferably consists of only acetonitrile. The amount of acetonitrile added is 15 v / w to 50 v / w, preferably 15 v / w to 40 v / w, more preferably 15 v / w to 30 v / w, even more preferably 18 v / w to 25 v / w, and most preferably 20 v / w. Note that the "v / w" in the amount of acetonitrile added refers to the volume (mL) of acetonitrile relative to the mass (1 g) of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one. Hereinafter, the same applies unless otherwise specified.

[0020] Examples of the "alkali metal iodide" used in this step include sodium iodide, potassium iodide, calcium iodide, and lithium iodide, with sodium iodide being preferred. The alkali metal iodides may be used alone, or two or more may be used in any combination and ratio. The amount of alkali metal iodide added is, for example, 0.01 to 2 equivalents, preferably 0.05 to 1.5 equivalents, more preferably 0.1 to 1 equivalent, even more preferably 0.15 to 0.5 equivalents, particularly preferably 0.2 to 0.4 equivalents, and most preferably 0.25 equivalents. The "equivalent" of the amount of alkali metal iodide added refers to the moles of alkali metal iodide relative to the mole of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one. The same applies hereinafter unless otherwise specified.

[0021] Examples of the "basic conditions" in this step include basic conditions using lithium carbonate, sodium carbonate, cesium carbonate, potassium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, lithium hydride, sodium hydride, potassium hydride, lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium tert-butoxide, sodium tert-butoxide, potassium tert-butoxide, alkyllithium (e.g., n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium), lithium amide (e.g., lithium diisopropylamide, lithium hexamethyldisilazide), sodium methoxide, sodium ethoxide, or tert-amine (e.g., trimethylamine, triethylamine, tripropylamine, triisopropylamine, diisopropylethylamine), and the like, preferably basic conditions using sodium bicarbonate, triethylamine, or diisopropylethylamine. The base may be used alone, or two or more types may be used in any combination and ratio. The amount of base added is, for example, 1 to 20 equivalents, preferably 1.5 to 15 equivalents, more preferably 2 to 10 equivalents, even more preferably 2.5 to 8 equivalents, particularly preferably 3 to 5 equivalents, and most preferably 3.15 equivalents. The "equivalent" of the amount of base added refers to the amount (moles) of base relative to the amount (1 mole) of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one. The same applies hereinafter unless otherwise specified.

[0022] The reaction temperature in this step is, for example, 40 to 100°C, preferably 50 to 90°C, more preferably 60 to 80°C, even more preferably 65 to 78°C, and most preferably 70 to 75°C.

[0023] The reaction time in this step is not particularly limited because it varies depending on conditions such as the reaction temperature, but is appropriately selected, for example, from within a range of 1 to 48 hours, preferably 3 to 36 hours, more preferably 6 to 30 hours, even more preferably 12 to 27 hours, particularly preferably 18 to 24 hours, and most preferably 20 hours.

[0024] The production method of the present invention includes the steps of concentrating the reaction mixture obtained in the above step to, for example, 3 to 12 v / w, preferably 4 to 10 v / w, more preferably 5 to 8 v / w, and most preferably 6 to 7 v / w, adding water and an acid to adjust the pH to a level at which (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof can be dissolved in water, and then extracting with an organic solvent. In this step, water is added to the reaction mixture, and then an acid is added to adjust the pH to an acidic level, for example, 3.0 or less, more preferably 2.0 or less, and most preferably 1.0 or less, and extraction with an organic solvent is carried out one or more times, preferably two or more times, more preferably three or more times, and most preferably four or more times. The "v / w" in the content of the reaction mixture means the volume (mL) of the reaction mixture relative to the mass (1 g) of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one.

[0025] The amount of water added in this step is, for example, 3 to 50 v / w, preferably 5 to 30 v / w, more preferably 7 to 20 v / w, even more preferably 8 to 15 v / w, and most preferably 10 v / w. The "v / w" amount of water added refers to the volume (mL) of water relative to the mass (1 g) of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one. The same applies hereinafter unless otherwise specified.

[0026] The acid used in this step is not particularly limited as long as it is an acid capable of adjusting the pH to a level at which (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof can be dissolved in water, and examples thereof include hydrochloric acid, sulfuric acid, and nitric acid, with hydrochloric acid being preferred. The amount of acid added is also not particularly limited as long as it is an amount capable of adjusting the pH to a level at which (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof can be dissolved in water.

[0027] Examples of organic solvents used in this step include chloroform, dichloromethane, diethyl ether, tetrahydrofuran (THF), ethyl acetate, hexane, and toluene, with ethyl acetate being preferred. The amount of organic solvent added is, for example, 5 v / w to 50 v / w, preferably 10 v / w to 40 v / w, and most preferably 10 v / w. Note that the "v / w" in the amount of organic solvent added refers to the volume (mL) of organic solvent relative to the mass (1 g) of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one.

[0028] The temperature at which water and acid are added in this step is, for example, -10 to 30°C, preferably -5 to 20°C, more preferably 0 to 15°C, and most preferably 0 to 10°C.

[0029] The production method of the present invention includes a step of adding a solvent to the organic layer obtained in the above step to cause crystallization. In this step, a solvent is added to the organic layer, and then a base is added to adjust the pH to alkaline, preferably 8 to 12, more preferably 9 to 11, and the mixture is stirred, thereby crystallizing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. The precipitated crystals are separated by filtration, washed, and dried to obtain high-purity (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0030] Examples of solvents used in this step include water, a mixture of methanol and water, a mixture of ethanol and water, a mixture of acetone and water, a mixture of methyl ethyl ketone and water, a mixture of acetonitrile and water, and a mixture of N,N-dimethylformamide and water, with a mixture of acetonitrile and water being preferred. When a mixture of acetonitrile and water is used as the solvent, the volume ratio of acetonitrile to water is, for example, 1:1 to 1:10, preferably 1:2 to 1:6, and most preferably 1:3 to 1:5. The amount of solvent added is, for example, 5 to 20 v / w, preferably 8 to 16 v / w, and more preferably 10 to 14 v / w. Note that the "v / w" in the amount of solvent added refers to the volume (mL) of solvent relative to the mass (1 g) of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one.

[0031] The base used in this step is not particularly limited as long as it can adjust the pH to an alkaline range, preferably 8 to 12, and more preferably 9 to 11, and examples thereof include lithium carbonate, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and lithium hydroxide, with potassium hydroxide being preferred. The amount of base added is also not particularly limited as long as it is an amount that can adjust the pH to an alkaline range, preferably 8 to 12, and more preferably 9 to 11.

[0032] The temperature during stirring in this step is, for example, -10 to 20°C, preferably -5 to 15°C, and most preferably 0 to 10°C.

[0033] The stirring time in this step is not particularly limited as it varies depending on reaction conditions such as temperature, but is appropriately selected, for example, from 1 to 24 hours, preferably 1 to 12 hours, more preferably 2 to 8 hours, and most preferably 3 to 5 hours.

[0034] The drying temperature in this step is not particularly limited as long as it is within a range that allows removal of adhering moisture or solution, but is, for example, 30 to 100°C, and preferably about 50°C.

[0035] The production method of the present invention can remove 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0036] The present invention also provides a method for producing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, which comprises a step of reacting 11-(2-iodoacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof with (R)-2-(diethylamino)methylpiperidine or a salt thereof in an organic solvent under basic conditions.

[0037] Examples of the "organic solvent" in this production method include acetonitrile, dimethylformamide (DMF), dimethylacetamide (DMA), dimethyl sulfoxide (DMSO), and ethyl acetate. The amount of organic solvent added is, for example, 3 v / w to 50 v / w, preferably 5 v / w to 30 v / w, more preferably 7 v / w to 20 v / w, even more preferably 8 v / w to 15 v / w, and most preferably 10 v / w. Note that the "v / w" in the amount of organic solvent added refers to the volume (mL) of organic solvent relative to the mass (1 g) of 11-(2-iodoacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one.

[0038] Examples of the "basic conditions" in this production method include basic conditions using sodium carbonate, cesium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium tert-butoxide, potassium tert-butoxide, alkyllithium (e.g., normal butyllithium, sec-butyllithium, tert-butyllithium, normal hexyllithium), lithium amide (e.g., lithium diisopropylamide, lithium hexamethyldisilazide), sodium methoxide, or tert-amine (e.g., trimethylamine, triethylamine, triisopropylamine, diisopropylethylamine), and preferably basic conditions using sodium bicarbonate, triethylamine, or diisopropylethylamine. The base may be used alone, or two or more types may be used in any combination and ratio. The amount of base added is 1 to 20 equivalents, preferably 1.5 to 15 equivalents, more preferably 2 to 10 equivalents, even more preferably 2.5 to 8 equivalents, particularly preferably 3 to 5 equivalents, and most preferably 3.15 equivalents. Note that the "equivalent" of the amount of base added refers to the amount (mol) of base relative to the amount (1 mol) of 11-(2-iodoacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one.

[0039] The reaction temperature in this production method is, for example, 40 to 100°C, preferably 50 to 90°C, more preferably 60 to 80°C, even more preferably 65 to 78°C, and most preferably 70 to 75°C.

[0040] The reaction time in the present production method is not particularly limited because it varies depending on conditions such as the reaction temperature, but is appropriately selected, for example, from a range of 1 to 48 hours, preferably 3 to 36 hours, more preferably 6 to 30 hours, even more preferably 12 to 27 hours, particularly preferably 18 to 24 hours, and most preferably 20 hours.

[0041] The present invention provides a method for purifying highly pure (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, which comprises a step of crystallizing the crude product (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof obtained by the production method of the present invention in a mixed solution of 1-propanol and water. In this purification method, the crude product (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof is mixed with 1-propanol, heated and stirred, cooled, and then water is added thereto and stirred, followed by further cooling, whereby (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof can be crystallized. The precipitated crystals are aged, separated by filtration, washed, and dried to give highly pure (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0042] In this purification method, the amount of 1-propanol added is, for example, 1 to 10 v / w, preferably 2 to 8 v / w, more preferably 3 to 15 v / w, and most preferably 4 v / w. In this purification method, the amount of water added is, for example, 1 to 15 v / w, preferably 2 to 10 v / w, more preferably 4 to 8 v / w, and most preferably 6 v / w. The "v / w" amounts of 1-propanol and water added refer to the volumes (mL) of 1-propanol and water per 1 g of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0043] The temperature of each step in this purification method can be adjusted appropriately. For example, when stirring in 1-propanol, the mixture is heated to, for example, 80 to 100°C, preferably 85 to 95°C. The mixture is then cooled to 40 to 60°C, preferably 45 to 55°C, and water is added and stirred. The mixture may then be further cooled to -5 to 10°C, preferably 0 to 5°C, for aging. The drying temperature may be any temperature within a range that allows removal of adhering moisture or solution, but is, for example, 80°C or lower, preferably about 50°C.

[0044] The stirring time in 1-propanol in this purification method is not particularly limited, but is appropriately selected, for example, from 1 to 5 hours, preferably from 2 to 4 hours, and most preferably from 3 hours. The stirring time after the addition of water is appropriately selected, for example, from 10 minutes to 5 hours, preferably from 20 minutes to 4 hours, and most preferably from 30 minutes to 3 hours.

[0045] This purification method can remove specific impurities derived from (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0046] The present invention also provides a method for purifying highly pure (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, which comprises a step of recrystallizing the crude product (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof obtained by the production method of the present invention in a solvent. This purification method includes a step of treating (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof with activated carbon in an alcoholic solvent, and / or a step of recrystallizing the same in a mixture of an alcoholic solvent and a ketone solvent. Specifically, the activated carbon treatment step includes a step of mixing AFDX0250 and activated carbon with an alcoholic solvent that serves as a good solvent, heating and stirring, filtering through charcoal, and concentrating the mixture. The recrystallization step includes a step of adding a ketone solvent that serves as a poor solvent to the concentrated mixture, heating and stirring, and cooling to crystallize AFDX0250. The precipitated crystals are then aged, separated by filtration, washed, and dried, thereby obtaining highly pure AFDX0250. To obtain AFDX0250 of higher purity, the same procedure can be repeated multiple times, excluding the addition of activated carbon and the charcoal filtration. Alternatively, the recrystallization step may be performed without the activated carbon treatment step.

[0047] Examples of the "alcohol solvent" in this purification method include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol, with ethanol and 1-propanol being preferred. The amount of the alcohol solvent added is, for example, 5 to 50 v / w, preferably 10 to 40 v / w, more preferably 15 to 30 v / w, and most preferably 20 v / w. The "v / w" in the amount of the alcohol solvent added refers to the volume (mL) of the alcohol solvent relative to the mass (1 g) of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0048] Examples of the "activated carbon" used in this purification method include Shirasagi A and Shirasagi P, with Shirasagi A being preferred. The amount of activated carbon added is, for example, 0.01 to 0.3 w / w, preferably 0.03 to 0.2 w / w, and most preferably 0.05 to 0.15 w / w. The "w / w" amount of activated carbon added refers to the mass (g) of activated carbon relative to the mass (1 g) of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0049] In this purification method, the mixture is concentrated after activated carbon filtration until the alcoholic solvent concentration is, for example, 0.5 to 3 v / w, preferably 1 to 3 v / w, and more preferably 2 to 2.5 v / w. During or after the concentration, a ketone solvent is added in an amount of, for example, 3 to 15 v / w, preferably 5 to 10 v / w, and more preferably 7 to 8 v / w, to obtain a mixture of alcoholic solvent and ketone solvent. When only the recrystallization step is performed without the activated carbon treatment step, the recrystallization solvent is similarly a mixture of alcoholic solvent and ketone solvent, and the amount of alcoholic solvent added is, for example, 0.5 to 3 v / w, preferably 1 to 3 v / w, and more preferably 2 to 2.5 v / w, and the amount of ketone solvent added is, for example, 3 to 15 v / w, preferably 5 to 10 v / w, and more preferably 7 to 8 v / w. The "v / w" units used to indicate the content of the alcohol solvent in the mixed solution and the amounts of the alcohol solvent and the ketone solvent added refer to the volumes (mL) of the mixed solution, the alcohol solvent, and the ketone solvent relative to the mass (1 g) of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0050] Examples of the "ketone solvent" in this purification method include acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diethyl ketone, etc., with acetone, MEK and MIBK being preferred.

[0051] The temperature of each step in the present purification method can be adjusted appropriately. For example, the activated carbon treatment step can be carried out by heating and stirring at a temperature of, for example, 50 to 90°C, preferably 60 to 80°C, and more preferably 65 to 75°C. The recrystallization step can be carried out by crystallizing at a temperature of, for example, 50 to 80°C, preferably 60 to 70°C, and more preferably 63 to 67°C, followed by stirring as necessary and cooling to, for example, -10 to 15°C, preferably -5 to 10°C, and more preferably 0 to 5°C. Furthermore, aging in the recrystallization step can be carried out at, for example, -10 to 15°C, preferably -5 to 10°C, and more preferably 0 to 5°C.

[0052] The heating and stirring time in the activated carbon treatment step in this purification method is not particularly limited because it varies depending on the conditions, but is appropriately selected, for example, from 30 minutes to 24 hours, preferably 40 minutes to 12 hours, more preferably 50 minutes to 6 hours, even more preferably 1 hour to 3 hours, and most preferably 1 hour. The aging time in the recrystallization step is, for example, 6 to 48 hours, preferably 12 to 36 hours, and most preferably 24 hours.

[0053] In the present invention, the starting material, intermediate, and / or manufactured compound (AFDX0250) may be in the form of a salt. The manufacturing method of the present invention also includes manufacturing methods that include such salt forms. The salt of such a compound is not particularly limited as long as it is a pharmaceutically acceptable salt. Examples of such salts include salts with inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, sulfuric acid, and phosphoric acid; salts with organic acids such as acetic acid, oxalic acid, fumaric acid, maleic acid, succinic acid, malic acid, citric acid, tartaric acid, adipic acid, gluconic acid, glucoheptoic acid, glucuronic acid, terephthalic acid, methanesulfonic acid, alanine, lactic acid, hippuric acid, 1,2-ethanedisulfonic acid, isethionic acid, lactobionic acid, oleic acid, gallic acid, pamoic acid, polygalacturonic acid, stearic acid, tannic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, lauryl sulfuric acid, methyl sulfate, naphthalenesulfonic acid, and sulfosalicylic acid; salts with metals such as sodium, potassium, calcium, and magnesium; salts with inorganic compounds such as ammonia; and salts with organic amines such as triethylamine and guanidine.

[0054] In the present invention, the starting material, intermediate, and / or produced compound (AFDX0250) or a salt thereof may be in the form of a hydrate or solvate.

[0055] The production method and purification method of the present invention can provide highly pure (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. The purity of the (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof is usually 95% or higher, preferably 97% or higher, more preferably 99% or higher, and most preferably 99.5% or higher.

[0056] By the production method and purification method of the present invention, the content of impurities in (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof can be removed to, for example, less than 5%, preferably less than 3%, more preferably 1%, and most preferably 0.5%. Here, in the present invention, "impurities" refer to impurities derived from (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, and (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. This refers to 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one, 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one, 11-(2-iodoacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one, and other substances that are mixed in during the production or purification of zepin-6-one or its salts.

[0057] In the present invention, the purity and impurity contents of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof can be measured by quantifying the peak area ratio in liquid chromatography (HPLC) by the area percentage method, which is a method well known in the field of analytical chemistry, or by liquid chromatography mass spectrometry (LC / MS).

[0058] (1) Method for measuring the content of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (AFDX0250) or its salt The content of AFDX0250 or its salt can be measured, for example, by the following method. <Mobile phase and dissolving solution> The following mobile phase and dissolving solution are used. Mobile phase A: 0.1 mol / L sodium perchlorate solution (pH 3.0) Dissolve 14.0 g of sodium perchlorate monohydrate in 1000 mL of water, and add 1 mol / L hydrochloric acid solution to adjust the pH to 3.0. Mobile phase B: acetonitrile Solvent A: mobile phase A: mobile phase B (1:1) (v / v) <Preparation of AFDX0250 standard solution> Accurately weigh out approximately 10 mg of AFDX0250 and add Solvent A to make exactly 100 mL. <Preparation of sample solution> Prepare sample solutions in the following manner. Sample solution A: Take 100-200 mg of the reaction suspension containing AFDX0250 (the reaction solution obtained in step 1 of Example 1 below) and dissolve it in 10 mL of Solvent A. Sample solution B: Take approximately 200 μL of the reaction suspension containing AFDX0250 (the reaction solution obtained in step 1 of Example 1 below) and filter it under reduced pressure using a Kiriyama funnel (S-40), Kiriyama filter paper (No. 3), and a suction bottle, and dissolve approximately 10 mg of the filtered material in 10 mL of Solvent A. Sample solution C: Approximately 10 mg of the obtained solid (AFDX0250 obtained in step 3 of Example 1 below) was accurately weighed, and dissolution liquid A was added to make exactly 100 mL. Sample solution D: Approximately 100 μL of the aqueous layer (the aqueous layer obtained in step 2 of Example 1 below) was accurately weighed, and dissolution liquid A was added to make exactly 10 mL. <Measurement method> Each sample solution was measured by liquid chromatography using the following method and conditions. Furthermore, the AFDX0250 content (%) was calculated using the following formula.(Liquid chromatography (UHPLC) test conditions) Detector: ultraviolet absorptiometer (measurement wavelength 210 nm) Column: AQUITY UPLC HSS T3 (inner diameter 2.1 mm, length 100 mm, particle size 1.8 μm; Waters) Ghost trap: Ghost trap DS-HP (P / N: 228-59931-91) (Shimadzu Corporation) or one with equivalent performance quality (the ghost trap is connected after the mobile phase mixer to remove impurities from the mobile phase.) Column temperature: around 40°C Sample cooler temperature: around 10°C Mobile phase A: 0.1 mol / L sodium perchlorate solution (pH 3.0) Mobile phase B: acetonitrile Mobile phase delivery: The mixing ratio of mobile phase A and mobile phase B is controlled to obtain a concentration gradient as shown in Table 1. Flow rate: 0.5 mL / min Injection volume: 2 μL Area measurement range: From after the solvent peak to 20 minutes after injection (Calculation formula) Sample solutions A to C: AFDX0250 content (%) = 100 x AAp / ATp AAp: AFDX0250 peak area obtained from the sample solution ATp: total peak area obtained from the sample solution Sample solution D: AFDX0250 content (%) = 100 x MS x AT x 10 / (MT x AS x 100) MS: collected amount of AFDX0250 (mg) MT: collected amount of sample solution (mg) AS: AFDX0250 peak area obtained from the standard solution AT: AFDX0250 peak area obtained from the sample solution

[0059] (2) Method for measuring the content of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (compound 1) The content of compound 1 contained in (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof can be measured, for example, by the following method. <Mobile phase and dissolving solution> The following mobile phase and dissolving solution are used. Mobile phase C: 10 mM ammonium acetate solution Dissolve 0.77 g of ammonium acetate in 1000 mL of water. Mobile phase B: acetonitrile Solvent B: mobile phase C: mobile phase B (7:3) (v / v) <Preparation of Compound 1 Standard Solution> Compound 1 Standard Stock Solution: Accurately weigh out approximately 20 mg of Compound 1 and add Solvent B to dissolve to exactly 100 mL. If it is difficult to dissolve, use ultrasound for approximately 1 minute to dissolve. Accurately measure 2 mL of this solution and add Solvent B to make exactly 20 mL. Accurately measure 1 mL of this solution and add Solvent B to make exactly 20 mL. Compound 1 Standard Solution 1: Accurately measure 4 mL of the standard stock solution and add Solvent B to make exactly 20 mL. Compound 1 Standard Solution 2: Accurately measure 2 mL of standard solution 1 and add Solvent B to make exactly 10 mL. Compound 1 Standard Solution 3: Accurately measure 2 mL of standard solution 2 and add Solvent B to make exactly 20 mL. <Preparation of Sample Solution> Prepare the sample solution using the following method. Sample Solution E (when the measurement target is the aqueous layer): Calculate the AFDX0250 content (%) of the aqueous layer obtained according to the measurement method in (1) above, and accurately weigh the aqueous layer so that it contains approximately 100 mg of AFDX0250. Add Dissolution Solution B to make exactly 25 mL. Sample Solution F (when the measurement target is crystals): Accurately weigh approximately 100 mg of AFDX0250, dissolve it with 5 mL of Dissolution Solution B and 0.2 mL of dilute hydrochloric acid, and add Dissolution Solution B to make exactly 25 mL (AFDX0250 concentration: approximately 4 mg / mL). If it is difficult to dissolve, dissolve it using ultrasound. <Measurement Method> Each sample solution was measured using liquid chromatography-mass spectrometry under the following conditions, in the order and for the number of times shown in Table 3 below.Furthermore, a calibration curve was created from the concentration (μg / mL) and peak area of ​​the standard solution (using a total of six results from standard solutions 1 to 3), and the compound 1 concentration (μg / mL) in the sample solution and the compound 1 content (ppm) in AFDX0250 were calculated using the following formula. (Liquid chromatography mass spectrometry (LC / MS) test conditions) Detector: Mass spectrometer Monitor ion: m / z 288 (ESI, Positive) Column: X Bridge C18 (inner diameter 2.1 mm, length 150 mm, particle size 3.5 μm; Waters) Column temperature: Approximately 40°C Sample cooler temperature: Flow-through temperature Mobile phase C: 10 mM ammonium acetate solution Mobile phase B: Acetonitrile Mobile phase delivery: The mixing ratio of mobile phase C and mobile phase B was controlled to a concentration gradient as shown in Table 2. Flow rate: 0.3 mL / min Injection volume: 5 μL Measurement order and number of times of sample solution: (Calculation formula) Sample solution E (when the object to be measured is the aqueous layer): Compound 1 concentration in sample solution E (μg / mL) = (AT - b) / a Compound 1 content in AFDX0250 (ppm) = Compound 1 concentration in sample solution E (μg / mL) / MT × P / 100 × 25000 AT: Peak area of ​​compound 1 obtained from sample solution E b: Intercept of calibration curve a: Slope of calibration curve MT: Amount of sample weighed (mg) P: AFDX0250 content (%) in the aqueous layer obtained according to the measurement method in (1) above Sample solution F (when the object to be measured is crystals): Compound 1 concentration in sample solution F (μg / mL) = (AT - b) / a Compound 1 content in AFDX0250 (ppm) = Compound 1 concentration in sample solution F (μg / mL) / MT × 25000 AT: Peak area of ​​compound 1 obtained from sample solution F b: Intercept of the calibration curve a: Slope of the calibration curve MT: Sample weight (mg)

[0060] The high-purity (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one of the present invention has a high purity of 95% or more and contains fewer impurities than (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one produced by a conventionally known method, and is therefore expected to be a safer pharmaceutical product.

[0061] The present invention also provides a pharmaceutical composition comprising (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, wherein the pharmaceutical composition is substantially free of impurities.

[0062] The pharmaceutical composition of the present invention comprises (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof with a purity of 95% or more, preferably 97% or more, more preferably 99% or more, and most preferably 99.5% or more.

[0063] The pharmaceutical composition of the present invention is preferably substantially free of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, and more preferably substantially free of 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, and more preferably substantially free of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. It is particularly preferred that the composition is substantially free of any substances other than (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one and 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one that may be contaminated during the production or purification process of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof. 5,11-Dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one is a compound represented by the following structural formula:

[0064] In the present invention, "substantially free" means that the composition is completely free of impurities such as 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one, that the presence of the impurities cannot be detected by methods commonly used in pharmaceutical analysis, such as liquid column chromatography using a chiral column (detector: ultraviolet spectrophotometry), or that the impurities are present in amounts that do not exert their effects or side effects. For example, the content of impurities in the pharmaceutical composition is less than 5%, preferably less than 3%, more preferably less than 1%, and most preferably less than 0.5%, relative to (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0065] In the present invention, the content of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof in the pharmaceutical composition is, for example, less than 1000 ppm, preferably less than 700 ppm, more preferably less than 500 ppm, even more preferably less than 300 ppm, still more preferably less than 100 ppm, particularly preferably less than 10 ppm, and most preferably less than 2 ppm, relative to the amount of (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0066] In the present invention, the content of 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof in the pharmaceutical composition is, for example, less than 1000 ppm, preferably less than 800 ppm, more preferably less than 600 ppm, and most preferably less than 500 ppm, relative to (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0067] In the present invention, the total amount of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one and 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one in the pharmaceutical composition is, for example, less than 2000 ppm, preferably less than 1000 ppm, more preferably less than 700 ppm, and most preferably less than 500 ppm, relative to (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0068] Unless otherwise specified, the pharmaceutical composition of the present invention may contain a pharmaceutically acceptable active ingredient other than (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, but in one embodiment, does not contain a pharmaceutically acceptable active ingredient other than (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

[0069] Additives may be used in the pharmaceutical composition of the present invention as needed, and examples of such additives include surfactants, isotonicity agents, stabilizers, preservatives, antioxidants, high molecular weight polymers, pH adjusters, and bases.

[0070] The pharmaceutical composition of the present invention is preferably an aqueous pharmaceutical composition, but may also be a non-aqueous pharmaceutical composition.

[0071] The pharmaceutical composition of the present invention can be administered orally or parenterally. Examples of routes of administration include oral administration, intravenous administration, transdermal administration, and topical ocular administration (e.g., eye drops, ophthalmic ointment, intraconjunctival sac administration, intravitreal administration, subconjunctival administration, sub-Tenon administration, insertion into the conjunctival sac, and application to the eyelid).

[0072] The dosage form of the pharmaceutical composition of the present invention is not particularly limited as long as it can be used as a pharmaceutical, and examples thereof include eye drops, eye gels, injections, etc. Eye drops are particularly preferred as the pharmaceutical composition of the present invention. Furthermore, when the pharmaceutical composition of the present invention is used as a non-aqueous pharmaceutical composition, it may be formulated as a non-aqueous preparation. These can be produced according to conventional methods in the art.

[0073] When the pharmaceutical composition of the present invention is prepared as an eye drop, the active ingredient is added to a medium such as purified water or a buffer solution, the mixture is stirred, and the pH is adjusted with a pH adjuster to prepare the desired eye drop. Furthermore, additives commonly used in eye drops may be used as needed. Examples of additives include isotonicity agents, buffering agents, surfactants, stabilizers, preservatives, solubilizers, etc.

[0074] When preparing oral preparations such as tablets, capsules, granules, powders, etc., they can be prepared by adding, as necessary, fillers, lubricants, binders, disintegrants, coating agents, film-forming agents, etc. Examples of fillers include lactose, crystalline cellulose, starch, vegetable oil, etc., lubricants include magnesium stearate, talc, etc., binders include hydroxypropyl cellulose, polyvinylpyrrolidone, etc., disintegrants include carboxymethylcellulose calcium, low-substituted hydroxypropyl methylcellulose, etc., coating agents include hydroxypropyl methylcellulose, macrogol (polyethylene glycol), silicone resin, etc., and film-forming agents include gelatin film, etc.

[0075] The dosage and administration of the pharmaceutical composition of the present invention can be varied as appropriate depending on the dosage form, the patient's symptoms, age, body weight, age at onset of the disease, the physician's judgment, etc. For example, when the pharmaceutical composition of the present invention is administered topically to the eye as eye drops, there are no particular limitations on the dosage and administration as long as it is sufficient to achieve the desired medicinal effect, and one to several drops can be instilled into the eye once to several times a day (e.g., 1 to 4 times, 1 to 6 times, 1 to 8 times). The composition can also be used while wearing contact lenses.

[0076] The pharmaceutical composition of the present invention can be used to treat eye diseases such as glaucoma, ocular hypertension, and myopia.

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0078] In the following examples, unless otherwise specified, HPLC (UHPLC) analysis and LC / MS analysis were carried out under the following conditions.

[0079] (HPLC (UHPLC) analysis conditions) Detector: ultraviolet absorptiometer (measurement wavelength 210 nm) Column: AQUITY UPLC HSS T3 (inner diameter 2.1 mm, length 100 mm, particle size 1.8 μm; Waters) Ghost trap: Ghost trap DS-HP (P / N: 228-59931-91) (Shimadzu Corporation) or one with equivalent performance quality (the ghost trap is connected after the mobile phase mixer to remove impurities from the mobile phase.) Column temperature: around 40°C Sample cooler temperature: around 10°C Mobile phase A: 0.1 mol / L sodium perchlorate solution (pH 3.0) Mobile phase B: acetonitrile Mobile phase delivery: The mixing ratio of mobile phase A and mobile phase B is controlled to obtain a concentration gradient as shown in Table 4. Flow rate: 0.5 mL / min Injection volume: 2 μL Area measurement range: from the solvent peak to 20 minutes after injection

[0080] (LC / MS analysis conditions) Detector: Mass spectrometer Monitor ion: m / z 288 (ESI, Positive) Column: X Bridge C18 (inner diameter 2.1 mm, length 150 mm, particle size 3.5 μm; Waters) Column temperature: Around 40°C Sample cooler temperature: Flow-through temperature Mobile phase C: 10 mM ammonium acetate solution Mobile phase B: Acetonitrile Mobile phase delivery: The mixing ratio of mobile phase C and mobile phase B is controlled by concentration gradient as shown in Table 5. Flow rate: 0.3 mL / min Injection volume: 5 μL Measurement order and number of times of sample solution:

[0081] Example 1: Production of AFDX0250 (1) (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (AFDX0250) was prepared according to the following steps.

[0082] Step 1 Under a nitrogen atmosphere, (R)-2-(diethylamino)methylpiperidine dihydrochloride (hereinafter sometimes referred to as "Compound 2"; 178 g, 0.732 mol), sodium iodide (26.0 g, 0.174 mol), and sodium bicarbonate (184 g, 2.19 mol) were added to an acetonitrile solution (3200 g) of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (Compound 1) (200 g, 0.695 mol) at room temperature, and the mixture was heated at an internal temperature of 73.0 to 74.5°C. The reaction solution at each time point (2 hours, 3 hours, 4 hours, and 5 hours after the reaction) was subjected to liquid chromatography (UHPLC), and AFDX0250, Compound 1, and 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (hereinafter sometimes referred to as "Compound 3") were quantified by the area percentage method.

[0083] Step 2: After allowing the reaction to proceed for 5 hours in Step 1, the reaction mixture was cooled and concentrated to obtain the crude product AFDX0250 (1231.56 g). Water (1800 g) was added, and concentrated hydrochloric acid (155 mL) was added dropwise at an internal temperature of 4.0 to 5.5°C until the pH reached 1 or less (pH 0.8). The mixture was then separated three times with ethyl acetate (1800 g). The aqueous layer of each separation was analyzed by liquid chromatography (UHPLC), and AFDX0250 and Compound 3 were quantified by the area percentage method. The content of Compound 1 was also measured by liquid chromatography mass spectrometry (LC / MS).

[0084] Step 3: To the aqueous layer obtained in Step 2, water (1400 g) and acetonitrile (780 g) were added and stirred at an internal temperature of 2.0 to 5.0°C. Subsequently, 3.25 N aqueous potassium hydroxide solution was added dropwise until the pH reached 11 or less, and the mixture was stirred for 5 hours. The precipitated solid was filtered under reduced pressure, and the filtered product was washed with water (2000 g) and then dried under reduced pressure at 50°C to obtain crude AFDX0250 (274.35 g, yield 93.3%) as a light brown solid. The obtained light brown solid was analyzed by liquid chromatography (UHPLC), and AFDX0250 and Compound 3 were quantified by the area percentage method. Furthermore, the content of Compound 1 was measured by liquid chromatography mass spectrometry (LC / MS).

[0085] The contents of AFDX0250 and Compound 3 in the reaction solution obtained in step 1, the aqueous layer obtained in step 2, and the solid obtained in step 3, and the content of Compound 1 in the reaction solution obtained in step 1 were measured in accordance with (1) the method for measuring the content of AFDX0250 or a salt thereof herein. The contents of Compound 1 contained in AFDX0250 in the aqueous layer obtained in step 2 and the solid obtained in step 3 were measured in accordance with (2) the method for measuring the content of Compound 1 herein.

[0086] The results of UHPLC analysis and LC / MS analysis of the reaction solution and sample solution in each step are shown in Table 7. Table 7 shows the contents of AFDX0250, Compound 1, and Compound 3. In the table, a) indicates the content of Compound 1 measured by liquid chromatography-mass spectrometry.

[0087] This test demonstrated that the production method of the present invention can remove Compound 1, which is positive in the Ames test, to an undetectable level, and can also produce AFDX0250 in high yield and high purity. Therefore, the production method of the present invention can produce AFDX0250 in high yield and high purity. Furthermore, it was demonstrated that AFDX0250 can be produced even when triethylamine is used instead of sodium bicarbonate in Step 1 above.

[0088] Example 2: Quantitative Analysis of AFDX0250 Produced by the Production Method of the Present Invention and a Known Production Method Quantitative analysis was performed on AFDX0250 produced by the production method of the present invention (using 20 mL of acetonitrile per 1 g of Compound 1 as the reaction solvent) and a known production method (using 10 mL of acetonitrile per 1 g of Compound 1 as the reaction solvent), and the area percentages of AFDX0250 and impurities were compared. Specifically, AFDX0250 was produced in the same manner as in Example 1, except that the batch amount of Compound 1 was changed from 200 g to 95 g, and the amounts of Compound 2 and reagents charged (equivalents per substance amount of Compound 1) were the same as in Example 1 (Example 2). AFDX0250 was also produced in the same manner as in Example 2, except that 10 mL of acetonitrile was used instead of 20 mL per 1 g of Compound 1 (Comparative Example 1). Test solutions were prepared from the resulting reaction solution in the same manner as in Example 1. UHPLC analysis was performed on each test solution.

[0089] Table 8 shows the results of UHPLC analysis of AFDX0250 obtained by the production method of the present invention (Example 2) and the known production method (Comparative Example 1).

[0090] This test demonstrated that the production method of the present invention can significantly remove impurities including Compound 1. Therefore, it was demonstrated that the production method of the present invention improves the purity of AFDX0250.

[0091] Example 3: Production of AFDX0250 (2) Compound 2 (135 g, 5.53 mol) and sodium bicarbonate (140 g, 16.6 mol) were added to a solution of 11-(2-iodoacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (hereinafter sometimes referred to as "Compound 4") (2.00 g, 5.27 mol) in acetonitrile (40.0 mL) at room temperature under a nitrogen atmosphere, and the mixture was heated at an internal temperature of 73.0°C for 23 hours. The reaction solution was filtered under reduced pressure, and the filtered product was washed five times with acetonitrile (2.0 mL). The filtrate was concentrated to dryness, and acetonitrile (7.60 mL) and water (9.20 mL) were added to the residue, which was dissolved by stirring and cooled to 0°C. 3.25 N potassium hydroxide was added to this solution until the pH reached 11.2-11.4, and the mixture was stirred at 0°C for 3 hours. The precipitated solid was filtered under reduced pressure and washed with water (13.2 mL) to obtain a wet solid, which was dried under reduced pressure at 50° C. to obtain AFDX0250 (1.04 g, yield 46.9%) as a light brown solid.

[0092] AFDX0250 １ The H-NMR data is as follows: １ H-NMR (400 MHz, CDCl ３ ) δ0.83-0.97 (m, 6H), 1.07-1.80 (m, 6H), 1.95-2.63 (m, 7.5H), 2.72-2.82 (m, 0.5H), 3.07-3.27 (m, 0.5H), 3.68 (s, 1H), 4.10-4.28 (m , 0.5H), 7.27-7.33 (m, 1H), 7.36-7.48 (m, 1H), 7.55-7.70 (m, 3H), 7.93 (d, J = 7.8Hz, 1H), 8.30 (d, J = 2.5Hz, 1H), 9.90-10.30 (br, 1H).

[0093] This test demonstrated that (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one can be produced even when 11-(2-iodoacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one is reacted with (R)-2-(diethylamino)methylpiperidine dihydrochloride.

[0094] Example 4: Purification of AFDX0250 (1) Under a nitrogen atmosphere, a solution of crude AFDX0250 (250 g, 0.593 mol) obtained in Example 1 in 1-propanol (800 g) was heated and stirred at an internal temperature of 89.7 to 90.1 ° C. for 3 hours at room temperature, then cooled to an internal temperature of 50.1 ° C. at a cooling rate of 0.5 ° C. / min, water (1500 g) was added at an internal temperature of 48.1 to 50.9 ° C. over 30 minutes, and then stirred at 50.3 to 50.9 ° C. for 30 minutes. Thereafter, the mixture was cooled to an internal temperature of 6.3 ° C. at a cooling rate of 0.5 ° C. / min, and stirred at an internal temperature of 0.8 to 6.3 ° C. for 17 hours. The precipitated solid was filtered under reduced pressure, washed with water (2500 g), and dried under reduced pressure at 50 ° C. to obtain purified crude AFDX0250 (217.09 g, yield 86.8%) as a light brown solid. The resulting light brown solid was subjected to liquid chromatography (UHPLC) to quantify AFDX0250, Compound 1, Compound 3, and a compound with a relative retention time of 1.06 (hereinafter sometimes referred to as "Compound 5") by the area percentage method. The content of Compound 1 was also measured by liquid chromatography mass spectrometry (LC / MS).

[0095] The results of the UHPLC analysis and LC / MS analysis are shown in Table 9. In the table, a) indicates the content of Compound 1 measured by liquid chromatography mass spectrometry.

[0096] This test demonstrated that the purification method of the present invention can produce AFDX0250 in a high yield and can further reduce the impurity compound 5 in addition to compounds 1 and 3. Therefore, by using the purification method of the present invention, AFDX0250 can be produced in a higher yield and with a higher purity.

[0097] Example 5: Purification of AFDX0250 (2) To ensure the proper properties and quality of pharmaceuticals, color, one of the indicators of drug substance properties, must be controlled during the drug substance manufacturing process. Therefore, crude AFDX0250 was heated and dissolved in an organic solvent, activated carbon was added, and the mixture was stirred. The activated carbon was then removed by filtration, decolorization, and removal of colored components were performed to purify AFDX0250. In this study, samples were prepared using Shirasagi A (0.05 w / w, 0.10 w / w, and 0.15 w / w) and Shirasagi P (0.10 w / w and 0.15 w / w) as activated carbon, and ethanol (EtOH), 1-propanol (1-PrOH), and N-methylpyrrolidone (NMP) as organic solvents. Note that samples containing NMP as a solvent were not prepared using Shirasagi A (0.15 w / w) or Shirasagi P (0.10 w / w and 0.15 w / w). The amounts of ethanol and 1-propanol added were each 20 mL per 1 g of crude AFDX0250, and the stirring temperature was 70°C. The amount of NMP added was 2.5 mL per 1 g of crude AFDX0250, and the stirring temperature was 70°C. To confirm whether the colored components had been removed, the properties of samples containing ethanol, 1-propanol, and NMP were confirmed before and after treatment with activated carbon. Furthermore, each sample was subjected to HPLC analysis at various time points (before the addition of activated carbon, 1 hour after the addition of activated carbon, and 3 hours after the addition of activated carbon).

[0098] The properties of each sample (powder and DMSO solution) before and after activated carbon treatment are shown in Figure 1. For the powders, each sample containing an organic solvent was filtered under reduced pressure, the filtrate was concentrated under reduced pressure, and the obtained wet solid was dried under reduced pressure at 50°C to confirm its properties. For the DMSO solutions, the obtained solid was dissolved in 10% dimethyl sulfoxide (DMSO) to form a solution, and its properties were confirmed. Furthermore, the results of HPLC analysis of samples containing ethanol (EtOH), 1-propanol (1-PrOH), and NMP are shown in Tables 10 to 12.

[0099]

[0100]

[0101] This test showed that the coloring components and impurity Compound 3 could be sufficiently removed by performing activated carbon treatment using an alcohol-based solvent.

[0102] Example 6: Purification of AFDX0250 (3) Under a nitrogen atmosphere, a solution of crude AFDX0250 (200 g, 0.474 mol) purified in Example 4 in ethanol (3200 g) was added to Shirasagi A (30.0 g), which was activated carbon, at room temperature. The mixture was heated and stirred at an internal temperature of 69.0 to 72.4 ° C. for 1 hour, then filtered under reduced pressure using a filtration apparatus filled with a filter aid and washed with ethanol (320 g) preheated to 70 ° C. The filtrate was concentrated under reduced pressure to obtain a concentrated residue (989.04 g).

[0103] In this test, in order to improve the efficiency of the purification process, the recrystallization step was carried out in conjunction with the activated carbon treatment step. The recrystallization step was carried out by combining the alcohol and anti-solvent used in the activated carbon treatment. Using ethanol or 1-propanol as the alcoholic solvent and ketone solvents such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), or n-heptane as the anti-solvent, the recrystallization step was carried out for each combination with a total solvent volume of 10 v / w (ratio 1:3) and 20 v / w (ratio 1:1), as follows: AFDX0250 in an alcoholic solution was heated and stirred at 50°C for 0.5 to 1 hour, and each anti-solvent was added to the solution, followed by heating and stirring for an additional 1 hour. The suspension was then cooled to 5°C and aged for 24 hours. The filtered product was dried under reduced pressure at 90°C. The properties of the resulting dried product were confirmed and HPLC analysis was performed. The dried product was also dissolved in 10% dimethyl sulfoxide (DMSO) to confirm its properties.

[0104] The properties of the dried products and DMSO solutions obtained in the recrystallization step using ethanol and 1-propanol as alcoholic solvents, as well as the properties of the dried products and DMSO solutions before purification, are shown in Figures 2 and 3. The results of HPLC analysis and yields of the dried products obtained in the recrystallization step using ethanol and 1-propanol as alcoholic solvents, as well as the dried products before purification, are shown in Tables 13 and 14, respectively.

[0105]

[0106] This test showed that by performing the recrystallization process using a mixed solvent of an alcoholic solvent and a ketone solvent, the coloring component and impurity Compound 1 can be sufficiently removed, and the purity of AFDX0250 can be increased.

[0107] Example 7: Purification of AFDX0250 (4) To the ethanol solution of AFDX0250 treated with activated carbon in Example 6, methyl isobutyl ketone (MIBK) (640 g) was added, and the mixture was concentrated. １ The mass volume percentages of ethanol and MIBK relative to AFDX0250 were calculated by H-NMR measurement, and the amount of ethanol was adjusted so that the total ethanol content was 2.5 v / w. The reaction mixture was then heated to 63-67°C and stirred for 30 minutes. MIBK was added dropwise over 48 minutes to a total of 7.5 v / w, and the mixture was stirred at 63-67°C for 1 hour. The reaction mixture was then cooled to 0-5°C, aged for 24 hours, and filtered to obtain crystals (first recrystallization). A test solution of the obtained AFDX0250 was prepared in accordance with (1) the method for measuring the content of AFDX0250 or its salt herein, and the test solution was subjected to HPLC analysis.

[0108] The resulting AFDX0250 was dissolved in ethanol, and the resulting solution was recrystallized a second time in the same manner as the first recrystallization. The resulting wet solid AFDX0250 was dried under reduced pressure at 90°C for 14 hours and 35 minutes to obtain AFDX0250 (152.27 g, yield 76.1%). As with the AFDX0250 obtained in the first recrystallization, a test solution was prepared for the resulting AFDX0250 in accordance with the method for determining the content of AFDX0250 or its salt (1) herein, and the test solution was subjected to HPLC analysis.

[0109] AFDX0250 １ The H-NMR data is as follows: １ H-NMR (400 MHz, CDCl ３) δ0.85-0.97 (m, 6H), 1.08-1.75 (m, 6H), 1.96-2.60 (m, 7.5H), 2.72-2.82 (m, 0.5H), 3.10-3.24 (m, 0.5H), 3.68 (s, 1H), 4.12-4.26 (m , 0.5H), 7.27-7.33 (m, 1H), 7.36-7.43 (m, 1H), 7.59-7.67 (m, 3H), 7.93 (d, J = 7.8Hz, 1H), 8.30 (d, J = 3.2Hz, 1H), 10.00-11.00 (br, 1H)

[0110] The results of HPLC analysis of AFDX0250 obtained by the first and second recrystallizations are shown in Table 15. In the table, "N.D." means "not detected," and a) indicates the content of Compound 1 measured by liquid chromatography-mass spectrometry.

[0111] This test showed that compound 5 could be sufficiently removed by performing activated carbon treatment followed by recrystallization, similar to compound 1. Therefore, it was shown that the purity of AFDX0250 could be further increased by combining activated carbon treatment and recrystallization steps.

[0112] According to the present invention, it is possible to produce (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof in a higher yield and with a higher purity than known methods. Furthermore, the content of impurities such as 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one can be reduced. Furthermore, according to the present invention, it is possible to provide highly purified (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof, and a pharmaceutical composition comprising highly purified (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one or a salt thereof.

Claims

1. A method for producing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, comprising the step of reacting (R)-2-(diethylamino)methylpiperidine or a salt thereof in an organic solvent under basic conditions in the presence of an alkali metal iodide, wherein the organic solvent contains 15 to 50 mL of acetonitrile per 1 g of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof.

2. The method for producing the product according to claim 1, wherein the organic solvent is 15 to 50 mL of acetonitrile per 1 g of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof.

3. The manufacturing method according to claim 1 or 2, further comprising the steps of adjusting the pH of the reaction mixture by adding water and acid, and then extracting it with an organic solvent.

4. The manufacturing method according to claim 3, wherein extraction with an organic solvent is performed two or more times.

5. The manufacturing method according to claim 3, wherein the organic solvent is ethyl acetate.

6. A method for producing (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, comprising the step of reacting (R)-2-(diethylamino)methylpiperidine or a salt thereof in an organic solvent under basic conditions.

7. A method for purifying (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, comprising the step of crystallizing the salt thereof in a mixture of 1-propanol and water.

8. A method for purifying (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, comprising the step of treating the salt or salt thereof with activated carbon in an alcoholic solvent.

9. A method for purifying (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, comprising the step of recrystallizing the salt in a mixture of an alcoholic solvent and a ketoneic solvent.

10. (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, with a purity of 95% or higher.

11. (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, having an impurity content of less than 5%.

12. A pharmaceutical composition comprising (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, wherein the content of impurities derived from (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof is less than 5% relative to (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof.

13. The pharmaceutical composition according to claim 12, wherein the impurity content is less than 1%.

14. A pharmaceutical composition comprising (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof, wherein 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one is substantially free of the pharmaceutical composition.

15. The pharmaceutical composition according to claim 14, wherein the content of 11-(2-chloroacetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one is less than 1000 ppm relative to (R)-11-[2-[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof.

16. The pharmaceutical composition according to claim 14 or 15, further comprising substantially no 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof.

17. The pharmaceutical composition according to claim 16, wherein the content of 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one or a salt thereof is less than 1000 ppm.