阅读说明：本技术 制备高纯度[4-(羟基氨基甲酰基)苯基]氨基甲酸{6-[(二乙基氨基)甲基]萘-2-基}甲酯的方法 (Process for preparing high purity {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate ) 是由 S·图尔凯塔 M·泽诺尼 E·乌卢奇 S·科乔洛 G·贝拉尔迪 N·毛卢奇 于 2020-03-05 设计创作，主要内容包括：描述了一种获得高纯度[4-(羟基氨基甲酰基)苯基]氨基甲酸{6-[(二乙基氨基)甲基]萘-2-基}甲酯和/或其药学上可接受的盐的方法。该方法能够获得任何单一未知杂质的量等于或小于0.10％的产品,以及纯度大于99.5％,优选等于或大于99.6％的产品。还描述了一种用于测定产物的纯度及其可能的杂质的HPLC方法。(A process is described for obtaining high purity {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or pharmaceutically acceptable salts thereof. The process enables to obtain a product with a quantity of any single unknown impurity equal to or lower than 0.10% and a purity higher than 99.5%, preferably equal to or higher than 99.6%. An HPLC method for determining the purity of the product and its possible impurities is also described.)

1. A process for the preparation of {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof in an amount equal to or less than 0.10% of any single unknown impurity, said process comprising the steps of:

i) preparing a solution or suspension of a compound of formula (II) in an organic solvent:

wherein X is halogen, preferably chlorine;

ii) adding hydroxylamine to the solution or suspension obtained in step i).

2. The process according to claim 1, wherein the organic solvent is selected from the group consisting of THF, methyl-THF, dioxane, ethylene glycol dimethyl ether and bis (2-methoxyethyl) ether.

3. The process according to claim 1 or 2, characterized in that the organic solvent is used in an amount between 1 and 100 parts by volume per part by weight of compound of formula (II).

4. A method according to any of the preceding claims, characterized in that the water content of the organic solvent is below 0.5%.

5. The process according to any of the preceding claims, characterized in that step ii) is carried out at room temperature.

6. The process according to any one of the preceding claims, characterized in that the process further comprises a step iii) of isolating the {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate as a free base or as a pharmaceutically acceptable salt, preferably as the hydrochloride salt, more preferably as the hydrochloride salt monohydrate.

7. Process according to any one of the preceding claims, characterized in that the compound of formula (II) is obtained from the corresponding acid of formula (I) by reaction with a halogenating agent in an aprotic dipolar solvent insensitive to acidity.

8. The process according to claim 7, characterized in that the aprotic dipolar solvent is selected from DMSO, acetonitrile, dimethylacetamide or dimethylformamide.

9. The process according to claim 7 or 8, characterized in that the halogenating agent is a chlorinating agent, preferably selected from thionyl chloride (SOCl)₂) Phosphorus trichloride (PCl)₃) Phosphorus oxychloride (POCl)₃) Or phosphorus pentachloride (PCl)₅)。

10. Process according to any one of claims 7 to 9, characterized in that the compound of formula (II) is isolated by precipitation with an organic solvent, preferably selected from aliphatic or aromatic hydrocarbons, ethers, esters or alcohols, more preferably toluene or THF.

11. Any single unknown impurity obtained by the process according to any of the preceding claims in an amount equal to or less than 0.10% of {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof.

12. {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof having a purity of greater than 99.5%, preferably equal to or greater than 99.6%, obtained by the process according to any one of claims 7 to 10.

13. (ii) 6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, in an amount equal to or less than 0.10% of any single unknown impurity, or in an amount equal to or less than 0.15%, preferably equal to or less than 0.10% of any single impurity other than intermediate (I) or amide (Ia).

14. {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, with a purity of greater than 99.5%, preferably equal to or greater than 99.6%.

15. A method for determining the purity of the product {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, which method comprises eluting the product through an HPLC column having a stationary phase comprising an alkyl chain, and subsequently detecting the product itself and impurities thereof through a detector, preferably of the UV, MS or RID type.

16. The process according to claim 15, characterized in that the alkyl chain is of octadecyl, octyl or butyl (C18, C8 or C4) type, preferably C18.

17. The method according to claim 15 or 16, characterized in that the stationary phase consists of particles of a support material comprising alkyl chains, preferably of silica, preferably of the type C18, C8 or C4.

18. The process of any one of claims 15 to 17, wherein the carbon loading of the stationary phase is less than 9 wt%.

19. The method according to any one of claims 15 to 18, wherein the elution phase consists of an aqueous solution, a polar organic solvent or a mixture thereof, preferably with the addition of a buffer.

20. The method of claim 19,the polar organic solvent is C₁-C₄Alcohol or acetonitrile, said C₁-C₄The alcohol is preferably methanol.

21. The process according to claim 20, characterized in that it is carried out according to the following operating conditions:

-a stationary phase: a carrier based on silica particles comprising C18 alkyl chains and a carbon loading of less than 9 wt%;

mobile phase A: water buffered at pH 3.7-3.8

Mobile phase B: methanol buffered at pH 3.7-3.8

The following gradient elution method was used:

22. (iii) methyl {6- [ (diethylamino) methyl ] naphthalen-2-yl } 4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, in an amount equal to or less than 0.10% of the unknown impurity at an RRT of 0.93 ± 0.02 and/or the unknown impurity at an RRT of 1.21 ± 0.02 and/or the unknown impurity at an RRT of 1.51 ± 0.02, preferably the amount is equal to or less than 0.10%, the RRT being determined using the HPLC method of claim 21.

23. A process for the preparation of {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, comprising a process according to any one of claims 15 to 21.

Technical Field

The object of the present invention is a process for obtaining high purity {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or pharmaceutically acceptable salts thereof. The process enables to obtain a product with a quantity of any single unknown impurity equal to or lower than 0.10% and a purity higher than 99.5%, preferably equal to or higher than 99.6%.

Another object of the invention is an HPLC method for determining the purity of the product and its possible impurities.

Background

(also known by the name ITF2357) (IUPAC name [4- (hydroxycarbamoyl) phenyl ]]Carbamic acid {6- [ (diethylamino) methyl group]Naphthalen-2-yl } methyl ester) is a hydroxamic acid used in the form of a hydrochloride salt, particularly hydrochloride monohydrate, which acts as an inhibitor of Histone Deacetylase (HDAC) and acts on both class I and class II enzymes in the same orientation.

Givinostat shows very promising activity profile in both in vivo and in vitro for multiple myeloma and acute myeloid leukemia, and also as an anti-inflammatory agent and an inhibitor of tumor necrosis factor alpha (TNF-alpha), IL-1 and IL-6 secretion.

Givinostat is currently used in multiple stage III studies of inflammatory diseases (duchenne and becker muscular dystrophy, juvenile arthritis and polycythemia vera) and in clinical trials of blood cancers (myeloma and lymphoma).

US 6034096 reports the preparation of givinostatt and US 7329689 and WO2004/065355 relate to the preparation and characterization of a polymorph monohydrate of Givinostat.

US 8518988 describes the preparation and characterization of anhydrous polymorphs of Givinostat.

The process described in the cited document for the preparation of Givinostat provides first the synthesis of the acid chloride (II) from intermediate (I) according to scheme 1 below (step 1), which is then added as a THF wet solid to an aqueous hydroxylamine solution and THF to give the final product (step 2):

scheme 1

The cited above documents do not describe any impurities produced in the synthesis.

The literature (a. furlan, v. monzani, l.l.reznikov, f.leoni, g.fossati.d.model na, p.massagni, c.a.dinarello, mol.med.2011,17(5-6)353-362) shows that intermediate (I) (ITF2375) and the corresponding amide (ITF2374) are the two major in vivo metabolites of givinostatt (ITF2357) resulting from the biotransformation of hydroxamic groups to carboxylic acids and amides, respectively.

The amide (ITF2374) has the following formula (Ia):

therefore, it is reasonable that the amount of intermediate (I) or amide (Ia) present in Givinostat is greater than 0.15%, which is a limited impurity.

According to the current guidelines in the pharmaceutical field, which provide a detailed description of the impurity profile of active ingredients intended for use in humans, it is of vital importance to develop new methods of producing Givinostat according to current quality standards and to determine new analytical techniques for determining the purity of Givinostat (e.g. to be able to determine the presence of any impurity).

Definition of

Unless defined otherwise, all technical terms, symbols, and other scientific terms used herein are intended to have the meanings commonly understood by those of skill in the art to which this application belongs. In some instances, for clarity and/or ease of reference, terms having commonly understood meanings are defined herein; accordingly, the inclusion of these definitions herein should not be construed to have a substantial difference from what is commonly understood in the art.

The term "physiologically acceptable excipient" herein denotes a substance which does not have any pharmacological effect per se and which does not produce adverse reactions when administered to a mammal, preferably a human being. Physiologically acceptable Excipients are well known in the art and are disclosed, for example, in Handbook of Pharmaceutical Excipients (sixth edition, 2009) and are incorporated herein by reference.

The term "pharmaceutically acceptable salt" refers to a salt that has the properties of being biologically effective and salt-forming compound and that does not produce adverse reactions when administered to a mammal, preferably a human. The pharmaceutically acceptable salt may be an inorganic salt or an organic salt; examples of pharmaceutically acceptable salts include, but are not limited to, carbonate, hydrochloride, hydrobromide, sulfate, bisulfate, citrate, maleate, fumarate, trifluoroacetate, 2-naphthalenesulfonate and p-toluenesulfonate. More information on pharmaceutically acceptable salts can be found in Handbook of pharmaceutical salts (P.Stahl, C.Wermuth, WILEY-VCH,127 & 133,2008) and is incorporated herein by reference.

The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") and are also to be construed as providing support for the term "consisting essentially of," or "consisting of.

The terms "consisting essentially of" and "consisting essentially of" should be interpreted as semi-enclosed terms, which means that no other ingredients (and thus optional excipients) having a substantial impact on the essential and novel features of the invention are included.

The terms "consisting of" and "consisting of" should be interpreted as closed terms. The term "high purity" means a purity of greater than 99.5%, preferably equal to or greater than 99.6%.

Within the scope of the present description, the term Givinostat or ITF2357 is intended to indicate the hydrochloride salt of the methyl [4- (hydroxycarbamoyl) phenyl ] carbamate {6- [ (diethylamino) methyl ] naphthalen-2-yl } ester, in particular the hydrochloride monohydrate (CAS number 732302-99-7). The CAS number for the hydrochloride salt is 199657-29-9, and the CAS number for the free base is 497833-27-9.

The term "halogen" denotes fluorine (F), chlorine (Cl), bromine (Br) or iodine (I).

The term "dipolar aprotic solvent insensitive to acidity" denotes a solvent which does not contain an acid sensitive component. THF is an example of an acid sensitive solvent. While DMSO, acetonitrile, dimethylacetamide or dimethylformamide are examples of solvents that are not sensitive to acidity.

The term "unknown impurity" means any unknown impurity present in {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof.

Disclosure of Invention

Referring to the methods used in the prior art for the preparation of givinostatt, the present inventors observed that these methods provided Givinostat with a single unknown impurity content of greater than 0.10%.

The applicant was therefore faced with the problem of developing a new process to prepare Givinostat with a content of any single unknown impurity equal to or less than 0.10% (area% in HPLC chromatogram), which is the expected level of ICH for unknown impurities when the daily dose of active substance is less than 2g (as is the case for Givinostat).

Surprisingly, it has been found that in step 1 (scheme 1), it is critical to carry out the halogenation reaction of intermediate (I) in a solvent free of acid sensitive components in order to reduce the halogenating agent equivalents required to complete the desired reaction, while obtaining intermediate (II) in an amount of impurities lower than that obtained by applying known techniques.

Also surprisingly, the inventors found that in step 2 (scheme 1), the order of addition of intermediate (II) and hydroxylamine is critical to obtain a final product with a single unknown impurity equal to or less than 0.10 area% in the relative purity analysis chromatogram.

Accordingly, in a first aspect, the present invention relates to a process for the preparation of {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or of a pharmaceutically acceptable salt thereof in an amount equal to or less than 0.10% of any single unknown impurity and/or having a high purity.

In a preferred embodiment, the process of the invention enables to obtain {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof in a purity of more than 99.5%, preferably equal to or more than 99.6%.

According to a second aspect of the present invention, the present invention relates to {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, in an amount equal to or less than 0.10% of any single unknown impurity, or in an amount equal to or less than 0.15%, preferably equal to or less than 0.10% of any single impurity other than intermediate (I) or amide (Ia).

According to a third aspect of the present invention, the present invention relates to {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, with a purity of more than 99.5%, preferably equal to or more than 99.6%.

According to a fourth aspect of the present invention, the present invention relates to a novel HPLC assay for determining the purity and detecting impurities of {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or of a pharmaceutically acceptable salt thereof.

According to a fifth aspect of the invention, the invention relates to methyl {6- [ (diethylamino) methyl ] naphthalen-2-yl } 4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, in an amount equal to or less than 0.10% of the unknown impurity at an RRT of 0.93. + -. 0.02 and/or the unknown impurity at an RRT of 1.21. + -. 0.02 and/or the unknown impurity at an RRT of 1.51. + -. 0.02 and/or the RRT is measured using the HPLC method according to the invention.

According to a sixth aspect of the present invention, the present invention relates to a process for the preparation of {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, said process comprising an HPLC method for determining purity according to the present invention.

Drawings

Figure 1 shows the chromatogram obtained by the HPLC method according to the invention on a specially prepared mixture containing all typical Givinostat impurities.

Detailed description of the preferred embodiments

The object of the present invention is a process for the preparation of {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or of a pharmaceutically acceptable salt thereof in an amount equal to or less than 0.10% of any single unknown impurity, said process comprising the steps of:

i) preparing a solution or suspension of a compound of formula (II) in an organic solvent:

wherein X is halogen, preferably chlorine;

ii) adding hydroxylamine to the solution or suspension obtained in step i).

Within the scope of the present description, steps i) and ii) will be referred to as step 2 of the method according to the invention.

In a preferred embodiment, the organic solvent of step i) in step 2 is selected from the group consisting of THF, methyl-THF, dioxane, ethylene glycol dimethyl ether and bis (2-methoxyethyl) ether.

Preferably, the organic solvent is used in an amount between 1 and 100 parts by volume per part by weight of compound of formula (II).

Preferably, the water content of the organic solvent is less than 0.5%.

Preferably, step ii) of step 2 of the process according to the invention is carried out at room temperature.

In a preferred embodiment, the process of the invention (step 2) is characterized in that it further comprises a step iii) of isolating the {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate as a free base or as a pharmaceutically acceptable salt (preferably the hydrochloride salt, more preferably the hydrochloride monohydrate)).

In another preferred embodiment, the compound of formula (II) is prepared from the corresponding acid of formula (I) by reaction with a halogenating agent, preferably a chlorinating agent, in an aprotic dipolar solvent insensitive to acidity: (Step a) And then obtaining the compound.

Preferably, the compound of formula (II) is isolated from the reaction mixture by precipitation with an organic solvent, preferably followed by filtration (II)Step b)。

Within the scope of the present description, steps a) and b) will be referred to as step 1 of the method according to the invention.

Solvents which are not sensitive to acidity are solvents which do not contain acid-sensitive components (and therefore do not contain THF, for example). This property of the solvent enables the use of smaller amounts of halogenating agent compared to the prior art.

By way of example, THF represents an acid-sensitive solvent, since under acidic conditions it decomposes and produces reactive species that can form undesirable by-products in halogenation reactions.

Preferably, in step a) of step 1, said aprotic dipolar solvent insensitive to acidity is selected from DMSO, acetonitrile, dimethylacetamide or dimethylformamide, preferably dimethylformamide.

An example of a chlorinating agent that can be used in the process of the present invention is thionyl chloride (SOCl)₂) Phosphorus trichloride (PCl)₃) Phosphorus oxychloride (POCl)₃) Or phosphorus pentachloride (PCl)₅). Alternatively, it is possible to useCorresponding brominating agent SOBr₂、PBr₃、POBr₃Or PBr₅。

In a preferred embodiment of step b) of step 1, the organic solvent used for precipitating compound (II) is selected from aliphatic or aromatic hydrocarbons, ethers, esters or alcohols, more preferably toluene or THF.

Another object of the present invention is the use of methyl [ 6- [ (diethylamino) methyl ] naphthalen-2-yl } carbamate and/or a pharmaceutically acceptable salt thereof in an amount equal to or less than 0.10% of any single unknown impurity, which can be obtained by applying only step 2 as defined above, with respect to the known art.

In another preferred embodiment, the present invention relates to {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, having a purity greater than 99.5%, preferably equal to or greater than 99.6%, which can be obtained by applying step 1 and step 2 as defined above, with respect to the known art.

Another object of the invention is {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, in an amount equal to or less than 0.10% of any single unknown impurity, or in an amount equal to or less than 0.15%, preferably equal to or less than 0.10% of any single impurity other than intermediate (I) or amide (Ia).

Another object of the invention is [ 6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, with a purity of more than 99.5%, preferably equal to or more than 99.6%.

Another object of the invention is [ 6- [ (diethylamino) methyl ] naphthalen-2-yl ] methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof, preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, in an amount equal to or less than 0.10% of the unknown impurity at an RRT of 0.93 ± 0.02 and/or the unknown impurity at an RRT of 1.21 ± 0.02 and/or the unknown impurity at an RRT of 1.51 ± 0.02 and/or the salt is preferably the hydrochloride salt, more preferably the hydrochloride monohydrate, RRT being determined using the HPLC method according to the invention.

In a preferred embodiment, RRT is measured using the following HPLC method:

-a stationary phase: a carrier based on silica particles comprising C18 alkyl chains and a carbon loading of less than 9 wt%;

mobile phase A: water buffered at pH 3.7-3.8

Mobile phase B: methanol buffered at pH 3.7-3.8

The following gradient elution method was used:

preferably, an ammonium formate-formic acid buffer with a pH of 3.7-3.8 is used.

Preferably, a 263nm UV detector is used.

Preferably, the column temperature is 25. + -. 1 ℃.

Preferably, the injection volume is 5 μ L.

Preferably, the flow rate is 0.25 mL/min.

Preferably, the product sample is diluted in DMSO.

Another object of the present invention is a pharmaceutical composition comprising {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or a pharmaceutically acceptable salt thereof as defined above and at least one pharmaceutically acceptable excipient.

In a preferred embodiment of the pharmaceutical composition, the active ingredient is in the form of micronized particles having a mean size of less than 200 μm, preferably between 100 μm and 1 μm, more preferably between 50 μm and 5 μm.

Another object of the invention is also a method for determining the purity of the product {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or of a pharmaceutically acceptable salt thereof, said method comprising elution of the product through an HPLC column having a stationary phase comprising an alkyl chain bonded to an inorganic carrier (e.g. silica), and subsequent detection of the same product and its impurities using a detector suitable for measuring the amount of analyte eluted from the column (e.g. a detector of the UV, MS or RID type).

In a preferred embodiment of the process according to the invention, the alkyl chain is of octadecyl, octyl or butyl (C18, C8 or C4) type, preferably C18. In an even more preferred embodiment, the stationary phase consists of a silica support derivatized with C18 alkyl chains and a carbon loading of less than 9 wt%.

Carbon loading means the carbon content of the stationary phase in weight% bound to the silica. High carbon loadings (15-25%) make the surface of the stationary phase more hydrophobic and can retain the most hydrophobic impurities, making it impossible to evaluate it correctly quantitatively.

A variety of columns of this type are commercially available, such as ACE 5C18-300, Halo C18 (solid), YMC-Pack OSD-A, BioBasic-18 PEEK. In a preferred embodiment, a column Halo is used(code 95812-902, manufactured by Advanced Materials Technology).

Different eluents selected from water, polar organic solvents or mixtures thereof may be used in combination with the stationary phase and detector as described above. The polar organic solvent is C1-C4 alcohol (preferably methanol) or acetonitrile.

Preferably, in the HPLC method of the invention, a mixture of water and methanol, a mixture of water and acetonitrile, optionally with or without an elution gradient, and optionally with or without a buffer, may be used. Preferably, the above mixture may be used with the addition of a buffer. More preferably, the ammonium formate-formic acid buffer has a pH of 3.7 to 3.8.

In a preferred embodiment, chromatographic runs according to the following scheme are used as the elution method:

wherein eluent a means water and ammonium formate-formic acid buffer at pH 3.7-3.8 and eluent B means methanol and ammonium formate-formic acid buffer at pH 3.7-3.8.

A further object of the present invention is also a process for the preparation of {6- [ (diethylamino) methyl ] naphthalen-2-yl } methyl [4- (hydroxycarbamoyl) phenyl ] carbamate and/or of a pharmaceutically acceptable salt thereof, said process comprising a method for determining the purity according to the invention.

The examples reported in the experimental section below are to be considered as examples of the objects of the process of the invention and do not constitute a limitation of the effective scope of the invention itself.

Experimental part

Example 1 (comparative)

Synthesis of intermediate (II) according to the prior art

73g (0.1796 mol) of intermediate (I) and 1.12L of dry THF are charged into a 2L reactor which has been previously dried and is under an inert atmosphere. The resulting suspension was stirred at room temperature for 30 minutes. The internal temperature was lowered to 3 ÷ 5 ℃ and 64g of thionyl chloride (0.538 moles) was added over 5 minutes, and then the reaction mixture was heated to reflux temperature and stirring continued for about 1 hour. 2g of dry DMF are added and the mixture is stirred at the same temperature for a further 4 hours. The reaction mixture was then concentrated under reduced pressure to a residual volume of about 0.3L. Then, 0.35L of toluene was added, and the mixture was concentrated again. This operation was repeated once. After the mixture was cooled to room temperature, dry THF (0.7L) was added and the mixture was stirred for about 30 minutes. The white precipitate of intermediate (II) was then filtered and washed with dry THF. The wet product (107g) was stored at 5 ℃ and used as such.

Example 2 (comparative)

Synthesis of Givinostat (experiment TT180) according to the prior art method

125mL of dry THF and 60mL of water were charged to a 1L reactor which had been previously dried and was under an inert atmosphere. To this solution was added an aqueous hydroxylamine solution (21g, 50% w/w) and the resulting mixture was cooled to 5 ℃. 19g of the wet intermediate (II) from example 1 (corresponding to 13g of the starting material intermediate (I)) were added in one portion and the internal temperature was gradually raised to 20. + -. 3 ℃. Gradual dissolution was observed and the resulting mixture was stirred continuously for 30-40 minutes. Then, water (55mL) was added followed by slow addition of 6N aqueous HCl (about 60g) until a pH <2 was reached while maintaining the internal temperature at 20 ± 3 ℃. THF was then removed under reduced pressure until the total volume was approximately halved and a white precipitate was observed. The mixture was cooled to 10 ℃ and stirring was continued at this temperature for 30 minutes. The product was isolated by vacuum filtration and washed with water. 16.4g of wet crude Givinostat are obtained.

Suspending the crude Givinostat in NaHCO at 20. + -. 3 ℃₃(6.5g) in 285mL of aqueous solution, then THF (265mL) was added and gradual dissolution was observed. The resulting solution was stirred for 30 minutes, then ethyl acetate (132mL) was added. After 15 minutes, the stirring was stopped and the two phases were allowed to separate. The aqueous phase was removed and the organic phase was treated with 37% HCl under vigorous stirring until the pH was reached<2. The resulting suspension was stirred for 30 minutes, then the precipitate was isolated by vacuum filtration and washed with THF. 17g of wet pure Givinostat were obtained.

The product was dried under reduced pressure in an oven at 30 ℃ for 16 hours. 7.2g of dry pure Givinostat are obtained, with a purity of 98.8% and showing the presence of 0.23% of unknown impurities.

Example 3

Synthesis of Givinostat according to the methods of the prior art (step 1) and of the invention (step 2) (experiment) TT177)

In a 1L reactor, previously dried and under an inert atmosphere, 29.3g of the wet intermediate (II) from example 1, corresponding to 20g of the starting material intermediate (I), were suspended in 192mL of dry THF and the internal temperature was brought to 20 ± 3 ℃. Aqueous hydroxylamine solution (32g, 50% w/w) was added in one portion and the mixture was stirred continuously for 30-40 minutes. Then, water (176mL) was added and gradual dissolution of the precipitate was observed. Aqueous 6N HCl (about 93g) was slowly added until a pH <2 was reached while maintaining the internal temperature at 20 ± 3 ℃. THF was then removed under reduced pressure until the total volume was approximately halved and a white precipitate was observed. The mixture was cooled to 10 ℃ and stirring was continued at this temperature for 30 minutes. The product was isolated by vacuum filtration and washed with water. 29g of wet crude Givinostat were obtained.

Wet crude Givinostat was suspended in NaHCO at 20. + -. 3 deg.C₃(10g) To 408mL of aqueous solution, then THF (408mL) was added and gradual dissolution was observed. The resulting solution was stirred for 30 minutes, then ethyl acetate (204mL) was added. After 15 minutes, the stirring was stopped and the two phases were allowed to separate. The aqueous phase was removed and the organic phase was treated with 37% HCl under vigorous stirring until the pH was reached<2. The resulting suspension was stirred for 30 minutes, then the precipitate was isolated by vacuum filtration and washed with THF. 31g of wet pure Givinostat were obtained.

The product was dried under reduced pressure in an oven at 30 ℃ for 16 hours. 15.6g of dry pure Givinostat are obtained. HPLC purity analysis showed the product to contain no unknown impurities in an amount greater than 0.10%.

Example 4

Synthesis of Givinostat (entry into Givinostat) according to the Process of the prior art (step 1) and the Process of the invention (step 2) TT183)

In a 1L reactor, previously dried and under an inert atmosphere, 29.3g of the wet intermediate (II) from example 1, corresponding to 20g of the starting material intermediate (I), were suspended in 192mL of dry THF and the internal temperature was brought to 20 ± 3 ℃. Aqueous hydroxylamine solution (32g, 50% w/w) was added by pouring over 15 minutes and the mixture was stirred continuously for 30-40 minutes. Then, water (176mL) was added and gradual dissolution of the precipitate was observed. Aqueous 6N HCl (about 91g) was slowly added until a pH <2 was reached while maintaining the internal temperature at 20 ± 3 ℃. THF was then removed under reduced pressure until the total volume was approximately halved and a white precipitate was observed. The mixture was cooled to 10 ℃ and stirring was continued at this temperature for 30 minutes. The product was isolated by vacuum filtration and washed with water. 36g of wet crude Givinostat were obtained.

Wet crude Givinostat was suspended in NaHCO at 20. + -. 3 deg.C₃(10g) To 408mL of aqueous solution, then THF (408mL) was added and gradual dissolution was observed. The resulting solution was stirred for 30 minutes, then ethyl acetate (204mL) was added. After 15 minutes, the stirring was stopped and the two phases were allowed to separate. The aqueous phase was removed and the organic phase was treated with 37% HCl under vigorous stirring until the pH was reached<2. The resulting suspension was stirred for 30 minutes, then the precipitate was isolated by vacuum filtration and washed with THF. 27g of wet pure Givinostat were obtained.

The product was dried under reduced pressure in an oven at 30 ℃ for 16 hours. 15.4g of dry pure Givinostat are obtained. HPLC purity analysis showed the product to contain no unknown impurities in an amount greater than 0.10%.

Example 5

Givinostat was synthesized according to the prior art method (step 1) and the method of the invention (step 2). On an industrial scale

In a 2000L reactor, previously dried and under an inert atmosphere, 50.0kg of wet intermediate (II) (corresponding to 40g of starting material intermediate (I)) are suspended in 400L of dry THF and the internal temperature is brought to 20 ± 3 ℃. An aqueous hydroxylamine solution (67.2kg, 50% w/w) was added by pouring over 15 minutes and the mixture was stirred continuously for 30-40 minutes. Then, water (447L) was added and gradual dissolution of the precipitate was observed. Aqueous 6N HCl (about 170kg) was slowly added until a pH <2 was reached while maintaining the internal temperature at 20 ± 3 ℃. THF was then removed under reduced pressure until the total volume was approximately halved and a white precipitate was observed. The mixture was cooled to 10 ℃ and stirring was continued at this temperature for 30 minutes. The product was isolated by vacuum filtration and washed with water. 60kg of wet crude Givinostat were obtained.

The wet crude Givinostat is suspended in NaHCO at 20. + -. 3 deg.C₃Gradual dissolution was observed in a solution of 860L aqueous solution (21kg) and 860L THF. The resulting solution was stirred for 30 minutes, then ethyl acetate (440L) was added. After 15 minutes, the stirring was stopped and the two phases were allowed to separate. The aqueous phase was removed and the organic phase was treated with 37% HCl under vigorous stirring until the pH was reached<2. The suspension obtained is stirred for 30 minutesThe precipitate was then isolated by vacuum filtration and washed with THF. 58kg of wet pure Givinostat were obtained.

The product was dried under reduced pressure in an oven at 30 ℃ for 16 hours. 35kg of dry pure Givinostat were obtained. HPLC purity analysis showed the product to contain no unknown impurities in an amount greater than 0.10% and to have an overall purity greater than 99.5%.

Example 6 (experiment TT259)

Synthesis of Givinostat according to the method of the invention (step 1+ step 2)

Step 1: synthesis of intermediate (II)

100g (0.2460 moles) of intermediate (I) and 300mL of dimethylformamide are charged to a 3L reactor previously dried and under an inert atmosphere. The suspension thus obtained was stirred at 20-25 ℃ for 30 minutes. 40g (0.3362 mol) of thionyl chloride were added and a slight exotherm was observed, controlled to maintain the reaction mixture at 20-25 ℃. The suspension obtained was kept at 20-25 ℃ for a further 2 hours, then subjected to two vacuum cycles and the pressure was restored with nitrogen to remove the gases produced by the reaction. 2000mL of THF was then added and the mixture was held at 20-25 deg.C for 1 hour. The suspension was then filtered on a buchner filter and washed with 300mL of THF. The wet product (133g) was stored at 5 ℃ and used as such.

Step 2: synthesis of Givinostat

133g of intermediate (II) from step 1 and 960mL of THF were charged to a 3L reactor previously dried and under an inert atmosphere. The obtained suspension is stirred at a constant temperature of 12-18 ℃. 160g (2.424 moles) of a 50% w/w aqueous solution of hydroxylamine were added to the suspension (the reaction was exothermic and the temperature of the mixture rose from 15 ℃ to 28 ℃). Then thermostated at 17-23 ℃ and kept under these conditions for 40 minutes.

Then, maintaining the same temperature, 1100mL of deionized water was added and gradual dissolution of the precipitate was observed. Finally, 220g of 15% w/w aqueous HCl solution were added until the pH of the mixture reached 1.2-1.8. The mixture was stirred continuously at 17-23 ℃ for 30 minutes, then concentrated under reduced pressure while maintaining the internal temperature at 25 ℃ until the residual volume was about 1400 mL. The pressure was then restored and 1000mL of deionized water was added. The mixture was then cooled to 7-13 ℃ and stirring was continued for 1 hour. The suspension was filtered by washing with 400mL of deionized water acidified with 1.2g of 37% HCl.

The wet filtrate was recharged to a reactor charged with 5kg sodium bicarbonate, 1000mL deionized water, and 1000mL THF. The mixture was stirred and heated to 47-53 ℃ and held under these conditions for 3 hours. The mixture was then cooled to 17-23 ℃ and the phases allowed to settle. The separated aqueous phase was back extracted with 500mL of ethyl acetate. The organic extracts were then combined and 200mL of 37% HCl was added to these extracts with vigorous stirring and precipitation of the product was observed. The mixture was stirred for 30 minutes, then filtered and the filter cake was washed with 400mL of THF.

The wet filtrate was recharged to a reactor charged with 5kg sodium bicarbonate, 1000mL deionized water, and 1000mL THF. The mixture was stirred at 17-23 ℃ and kept under these conditions for 30 minutes. Then 500mL of ethyl acetate was added to the mixture at 17-23 ℃ and stirred for 15 minutes. The phases were allowed to settle and the separated organic phase was filtered on a 10 micron microporous filter. The reactor and lines were then rinsed with a mixture of 120mL of THF and 60mL of ethyl acetate, and 200mL of 37% HCl was added to the combined organic phases and the precipitation of the product was observed. The mixture was stirred for 30 minutes, then filtered and the filter cake was washed with 400mL of THF. The product (157g) was removed and dried under vacuum (<50mbar) at 25-35 ℃ for 15 hours. 107g of final product were obtained.

Example 7 (experiment TT267)

Givinostat was synthesized according to the method of the invention (step 1+ step 2).

The preparation of intermediate (II) was repeated and then converted to Givinostat as described in example 6. At the end of the process, 105g of product were obtained.

Example 8 (experiment TT287)

Givinostat was synthesized according to the method of the invention (step 1+ step 2).

100g (0.2460 moles) of intermediate (I) and 300mL of dimethylformamide are charged to a 3L reactor previously dried and under an inert atmosphere. The resulting suspension was stirred at 20-25 ℃ for 30 minutes. 40g (0.3362 mol) of thionyl chloride are then added and a slight exotherm is observed which is controlled to maintain the reaction mixture at 20-25 ℃. The suspension obtained was kept at 20-25 ℃ for a further 2 hours, then subjected to two vacuum cycles and the pressure was restored with nitrogen to remove the gases produced by the reaction. 2000mL of toluene was then added and the mixture was held at 20-25 ℃ for 1 hour. The suspension was then filtered on a buchner filter and washed with 300mL of toluene. The wet product (133g) was stored at 5 ℃ and used as such.

133g of intermediate (II) from the preparation and 960mL of THF were charged to a 3L reactor which had been previously dried and was under an inert atmosphere. The obtained suspension is stirred at a constant temperature of 12-18 ℃. 160g (2.424 moles) of a 50% w/w aqueous solution of hydroxylamine were added to the suspension (the reaction was exothermic and the temperature of the mixture rose from 15 ℃ to 28 ℃). Then, the temperature was maintained at 17-23 ℃ for 40 minutes under these conditions.

Then, the same temperature was maintained, 1100mL of deionized water was added while maintaining the temperature at 17-23 ℃, and gradual dissolution of the precipitate was observed. Finally, 220g of 15% w/w aqueous HCl solution were added until the pH of the mixture reached 1.2-1.8. The mixture was stirred continuously at 17-23 ℃ for 30 minutes and then concentrated under reduced pressure while maintaining the internal temperature at 25 ℃ until a residual volume of about 1400mL was reached. The pressure was then restored and 1000mL of deionized water was added. It was then cooled to 7-13 ℃ and stirring was continued for 1 hour. The suspension was filtered by washing with 400mL of deionized water acidified with 1.2g of 37% HCl.

The wet filtrate was recharged to a reactor charged with 5kg sodium bicarbonate, 1000mL deionized water, and 1000mL THF. The mixture was stirred and heated to 47-53 deg.C and these conditions were maintained for 3 hours. The mixture was then cooled to 17-23 ℃ and the phases allowed to settle. The separated aqueous phase was back extracted with 500mL of ethyl acetate. The organic extracts were then combined and 200mL of 37% HCl was added to these extracts with vigorous stirring and precipitation of the product was observed. The mixture was stirred for 30 minutes, then filtered and the filter cake was washed with 400mL of THF.

The wet filtrate was recharged to a reactor charged with 5kg sodium bicarbonate, 1000mL deionized water, and 1000mL THF. The mixture was stirred at 17-23 ℃ and these conditions were maintained for 30 minutes. Then 500mL of ethyl acetate was added to the mixture at 17-23 ℃ and stirred for 15 minutes. The phases were allowed to settle and the separated organic phase was filtered on a 10 micron microporous filter. The reactor and lines were then rinsed with a mixture of 120mL of THF and 60mL of ethyl acetate, and 200mL of 37% HCl was added to the combined organic phases and the precipitation of the product was observed. The mixture was stirred for 30 minutes, and the filter cake was filtered and washed with 400mL of THF. The product (157g) was removed and dried under vacuum (<50mbar) at 25-35 ℃ for 15 hours. 107g of final product were obtained.

Example 9

HPLC method for determining Givinostatt purity and impurities thereof

Sample preparation

About 20mg of ITF2357 sample was accurately weighed, transferred to a 100mL flask, and filled to volume with DMSO (concentration 0.20 mg/mL).

Figure 1 shows a typical chromatogram obtained by the HPLC method according to the invention on a mixture of all typical impurities of a particular prepared product.

Example 11

In a prior art method (example 2), a method known in the art (step 1) and a method of the invention (step 2) Examples 3 and 4, and Givinostat obtained in pure form by the process of the invention (step 1 and step 2) (examples 6, 7 and 8) Degree analysis

TABLE 1

Table 1 shows in particular the relative retention times of Givinostat (RRT 1), amide metabolite (Ia) (RRT 1.08), intermediate (I) (RRT 1.27) and unknown impurities assessed by HPLC analysis as described in example 9.

Experiment TT180 (example 2) relates to a repetition of the process used in the prior art, whereas experiments TT 177 (example 3) and TT 183 (example 4) relate to an experiment applying the process of the invention to step 2, in which a 50% aqueous hydroxylamine solution is added to a solution of intermediate (II) dissolved in THF produced according to known techniques.

From the analysis of the purity data of table 1, it can be seen that the reverse order of addition (addition of hydroxylamine to intermediate (II)) can reduce all unknown impurities to below 0.10% based on the final reaction product compared to the standard order of addition (addition of intermediate (II) to hydroxylamine). In turn, using standard methods, one impurity is well above the 0.10% limit.

Another key aspect to limit the formation of impurities is that the amount of water contained in the mixture comprising intermediate (II) to which the hydroxylamine is added must be limited to within 0.5% based on the weight of the mixture. On the other hand, the hydroxylamine addition time does not constitute a limitation, and unlike the prior art processes, the process of the present invention can be operated at room temperature rather than at 5 ℃.

In examples 6, 7 and 8, two innovative points of the present invention were applied to step 1 and step 2. As is clear from the values reported in the table, Givinostat is obtained with a purity of greater than 99.5%, preferably equal to or greater than 99.6%, and no unknown impurities are detected (detection limit of the method is 0.02%).