Method for industrially producing disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alanine

Abstract

The present invention relates to an industrial process for the preparation of the acid of formula (E) below, ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((((R)-1-aminoethyl)(hydroxy)phosphoryl)methyl)propanoyl)-L-alanine, via a multi-step synthesis starting from (S)-1-phenylethylamine. The present invention relates to an industrial process for the preparation of the disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alanine, of formula (I) below, in two further steps starting from compound (E) as defined above. The present invention also relates to a process for diastereoisomeric enrichment of intermediates in the industrial process for the preparation of the compound of formula (E) of the present invention. [Formula 1] TIFF2023505577000034.tif58168 [2] TIFF2023505577000035.tif58168

Description

[Technical field]

[0001] The present invention relates to a novel industrial process for producing the disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alanine from (S)-1-phenylethylamine. [Background technology]

[0002] The designated compound (I) of the formula:

[0003] [ka]

[0004] The disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alanine, is a prodrug of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((((R)-1-aminoethyl)(hydroxy)phosphoryl)methyl)propanoyl)-L-alanine aminophosphinic acid (designated compound (E) herein), which is a selective dual inhibitor of neutral aminopeptidase (NAP) and neprilysin (NEP).

[0005] Compound (I) has been described by Bonnard et al. in Pharmacol. Res. Perspect., 2015, 3(2), e00116 as having potent analgesic effects.

[0006] Compound (I) and its use as an analgesic were first described in patent application WO 2010 / 010106. According to the method presented in this application, it is possible to prepare ((R)-1-(((benzyloxy)carbonyl)amino)ethyl)phosphinic acid (Example 1, step 3) from diphenylmethylamine hydrochloride in four steps. This aminophosphinic acid is then reacted with 2-([1,1'-biphenyl]-4-ylmethyl)acrylic acid to obtain compound (I) in six further steps. This synthesis method requires, inter alia, lyophilization in the final step.

[0007] The technical aspects particularly related to this synthesis, in particular freeze-drying, the number of equivalents, the use of certain difficult to handle reagents and / or purification techniques involved in this process, do not allow the transfer of the synthetic route described in WO 2010 / 010106 to an industrial scale, in particular - the chemical resolution of the racemate obtained in the second step of the process with (R)-methylbenzylamine (see example 1, step 3), as described in the publication by Baylis et al., J. Chem. Soc., Perkin trans. I, 1984, pp. 2846-2853, strongly influences the yield of this step, since at least half of the product is lost (86% of the correct stereoisomer corresponding to 50% of the starting racemic mixture is recovered, i.e. the overall yield of the correct stereoisomer for this step is 43%). - A saponification step is also carried out (see Example 3, step 2). This particular reaction is difficult to carry out on an industrial scale, in particular due to the production of significant amounts of benzyl alcohol, which makes its isolation difficult and leads to the formation of large amounts of impurities. - Deprotection to obtain the compound described in Example 3, step 2, requires deprotection in a strongly acidic medium (33% HBr in acetic acid), which requires large amounts of corrosive acid, which is difficult to remove. - The by-product of step 3 (4-nitrophenol) is removed by purification on a silica column to give the compound described in Example 3, step 3. During the penultimate step, the compound of example 3, step 4 must be deprotected to give the compound of example 4, which is then salified during the final step to give compound (I). In addition, the synthesis requires the use of diphenylmethylamine as starting material, which has a very significant impact on the cost of raw materials.

[0008] An important objective for the development of large-scale organic synthesis is to find a synthesis method that is completely transferable to industrial conditions. In this respect, the various parameters of the synthesis should be optimized, in particular, for example, the solvent should be as low volatile as possible so that it can be easily recovered, and the temperature used should be in an easily accessible temperature range. It is also advantageous that the purification of the various intermediates and products can be carried out in a simple manner and under conditions compatible with large scale. Finally, the mixtures and products of the reaction should be isolated and thermally stable.

[0009] Good manufacturing practice (GMP) regulations govern the manufacture of pharmaceutical products that may be administered to humans or animals. GMP regulations require a quality approach to manufacturing, which allows companies to minimize or eliminate instances of contamination, mix-ups, and errors.

[0010] To the best of the inventors' knowledge, no industrial method has been described that allows compound (I) to be synthesized.As a result, there is a need to develop a method for synthesizing compound (I) that can be easily and efficiently adapted to industrial scale, in particular a method that does not use toxic solvents, column chromatography, and lyophilization.In addition, it would be interesting if this synthetic method allows the number of steps and the associated costs of raw materials to be reduced. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] WO 2010 / 010106 [Non-patent literature]

[0012] [Non-Patent Document 1] Bonnard et al., Pharmacol. Res. Perspect., 2015, 3(2), e00116 [Non-Patent Document 2] Baylis et al., J. Chem. Soc., Perkin trans. I, 1984, pp. 2846-2853. [Non-Patent Document 3] TW Greene, "Protective Groups In Organic synthesis", (John Wiley & Sons, New York (1981)) [Non-Patent Document 4] Harrison et al., Compendium of Synthetic Organic Methods, volumes 1 to 8, (J. Wiley & sons, 1971 to 1996) [Non-Patent Document 5] Hamilton et al., Tet. Lett., 1995, 36, pp. 4451-4454. [Non-Patent Document 6] Organic Synthesis Coll., vol. 3, p. 337 Summary of the Invention [Means for solving the problem]

[0013] The present invention relates to a compound represented by the following formula (I):

[0014] [ka]

[0015] (In the formula, the symbols (1R) and (2S) represent the positions of the atoms they represent in the molecule and their absolute configuration. The symbol * represents a chiral carbon.) This invention relates to a process for industrially producing the disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alanine.

[0016] The method of the present invention comprises the following sequential steps: (1) A compound of the following formula (A):

[0017] [ka]

[0018] (1a) reacting (S)-1-phenylethylamine with an aqueous solution of hypophosphorous acid, HPO, and acetaldehyde in a polar, protic solvent in the presence of a molar equivalent, or less than 0.1 molar equivalent, of hydrochloric acid relative to the (S)-1-phenylethylamine; (1b) then treating the resulting salt from step (1a) with propylene oxide; (1c) then crystallizing using a polar and protic solvent and recovering the compound of formula (A) by filtration. and (2) A compound of the following formula (B):

[0019] [ka]

[0020] (2a) reacting the compound of formula (A) derived from step (1) with the benzyl ester of (2-(4-biphenyl)methyl)acrylate in the presence of a source of trimethylsilyl group; (2b) then reacting the compound of formula (B) with (2b.1) crystallization using a mixture of a non-polar aprotic solvent and water, followed by filtering; or (2b.2) triturating in acetone, filtering and evaporating the filtrate The process of recovering by and (3) A compound of the following formula (C):

[0021] [ka]

[0022] where P' is a protecting group for the amine functionality. (3a) hydrogenolysis of the compound of formula (B) under a hydrogen atmosphere in the presence of 10% by weight of Pd / C relative to the weight of the compound of formula (B); (3b) then protecting the amine resulting from step (3a) with a protecting group P' to recover a compound of formula (C). and (4) A compound of the following formula (E):

[0023] [ka]

[0024] (4a) peptide coupling of the compound of formula (C) with tert-butyl ester of (L)-alanine to obtain a compound of formula (D):

[0025] [ka]

[0026] (4b) Deprotecting the protecting group P′ at the N-terminal position and the tert-butyl group at the C-terminal position to recover the compound of formula (E). and (5) A compound of the following formula (F):

[0027] [ka]

[0028] preparing a compound of formula (E) by reacting with an acyloxyalkyl N-hydroxysuccinimide in the presence of a base; (6) thereafter recovering the compound of formula (I) by precipitation in a non-polar aprotic solvent in the presence of a sodium salt of a weak base; Includes.

[0029] Another object of the present invention relates to a process for the industrial preparation of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((((1R)-1-aminoethyl)(hydroxy)phosphoryl)methyl)propanoyl)-L-alaninic acid of formula (E), comprising the successive steps (1) to (4) as defined above.

[0030] The present invention also relates to a process for diastereoisomerically enriching an intermediate in the industrial process for producing the compound of formula (E) of the present invention.

[0031] Another object of the present invention relates to a synthetic intermediate of formula (B) as described above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] In the description that follows, all percentages are expressed as mole percentages unless otherwise specified.

[0033] The present invention relates to a multi-step synthesis for the industrial production of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((((1R)-1-aminoethyl)(hydroxy)phosphoryl)methyl)propanoyl)-L-alanine acid of formula (E) and also of the disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alanine of formula (I).

[0034] "First alternative of the invention" refers to an alternative in which the synthesis of the compound of formula (B) advantageously involves carrying out step (2b.1) immediately after step (2a). Step (2b.2) is therefore not carried out. According to this alternative, the compound of formula (B) resulting from step (2b) has an optical purity (2S / 2R) of 95 / 5 or more. This enantiomeric enrichment is then also preserved during steps (3) and (4), respectively, for the synthesis of compounds (C), (D) and (E). Thus, according to this first alternative, each of compounds (B), (C), (D) and (E) corresponds to a diastereoisomer as expressed in the corresponding formula, strictly with a diastereoisomeric excess of more than 95%, more preferably more than 99%.

[0035] "Second alternative of the invention" refers to an alternative in which the synthesis of the compound of formula (B) advantageously involves carrying out step (2b.2) immediately after step (2a). Step (2b.1) is therefore not carried out. According to this alternative, the compound of formula (B) resulting from step (2b) has an optical purity (2S / 2R) strictly greater than 50 / 50 and less than or equal to 95 / 5, in particular comprised between 51 / 49 and 60 / 40. According to this second alternative, each of steps (3) and (4) may be followed by a diastereomeric enrichment step in order to increase the diastereomeric excess of each of compounds (C) and (E).

[0036] According to the present invention, unless otherwise specified, compound (A), compound (F) and compound (I) correspond to the enantiomers or diastereoisomers as expressed in the corresponding formula, advantageously precisely in an enantiomeric or diastereomeric excess of more than 95%, more preferably more than 99%.

[0037] It should be noted that the terms "enantiomeric excess" or "diastereomeric excess" are interchangeable with the terms "optical purity" and "chiral purity". "Optical purity greater than Y / Z (XR / XS)" is taken to mean, in the sense of the present invention, that the atom at position X is a chiral center found in Y % of the R configuration and Z % of the S configuration.

[0038] "Optical purity XR / XS strictly greater than 50 / 50" is understood in the sense of the present invention to mean that the enantiomer XR is found in a greater proportion than the enantiomer XS strictly.

[0039] "Concentrated hydrochloric acid" is understood in the sense of the present invention to mean an aqueous solution of hydrochloric acid containing between 33% and 37% by weight of hydrochloric acid, preferably a concentrated solution of 37% by weight.

[0040] "Source of trimethylsilyl group" is understood in the sense of the present invention to mean a chemical compound capable of providing one or more trimethylsilyl (TMS) groups of formula -Si(CH3)3. In other words, when it reacts with another compound, the TMS source compound is capable of delivering one or more TMS groups to said compound. These TMS source compounds are generally used as reagents for protecting functional groups such as hydroxyl or amine with TMS groups. Examples of TMS source compounds include N,O-bis(trimethylsilyl)acetamide (BSA), TMS chloride (TMSCl), TMS triflate (TMSOTf), and hexamethyldisilazane (HMDS).

[0041] "Room temperature" is taken to mean, within the meaning of the present invention, a temperature comprised between 15°C and 30°C, preferably between 18°C ​​and 25°C.

[0042] As used herein, the term "equivalents" refers to molar equivalents, unless otherwise specified.

[0043] "Protecting group", in the sense of the present invention, is taken to mean a group that makes it possible to protect a reactive chemical functional group against undesired reactions, such as those described by TW Greene, "Protective Groups In Organic synthesis", (John Wiley & Sons, New York (1981)) and Harrison et al., "Compendium of Synthetic Organic Methods", volumes 1 to 8, (J. Wiley & sons, 1971-1996).

[0044] "Partial racemization", in the sense of the present invention, is understood to mean that a so-called "pure" enantiomer, i.e. an enantiomer with an enantiomeric excess of at least 95%, preferably at least 99%, is converted into a mixture of two enantiomers of the same compound, where these two enantiomers are in unequal amounts, with one enantiomer predominating over the other, as opposed to total racemization, where the two enantiomers are found in identical amounts.

[0045] In the present invention, the expression "on the carbon at the 2-position" refers to the carbon at the 2-position according to the IUPAC notation, which bears a methylbiphenyl group, as represented in the above formulas (B), (C), (D), (E), (F), and (I).

[0046] The following abbreviations are used herein: Bn: Benzyl; HPLC: High Performance Liquid Chromatography; TMS: trimethylsilyl; BSA: N,O-bis(trimethylsilyl)acetamide; TMSOTf: TMS triflate; HMDS: hexamethyldisilazane; MTBE: methyl tert-butyl ether; THF: tetrahydrofuran; DMF: dimethylformamide; Boc: tert-butoxycarbonyl; CBz: benzyloxycarbonyl; TBTU: 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate; HATU: (dimethylamino)-N,N-dimethyl(3H-[1,2,3]triazolo[4,5-b]pyridin-3-yloxy)methaniminium hexafluorophosphate; BOP: benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate; PyBOP: benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate; HOBt: hydroxybenzotriazole; DCC: dicyclohexylcarbodiimide; EDC: 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; DIPEA: diisopropylethylamine; Pd / C: palladium / carbon.

[0047] Process for preparing a compound of formula (E) The object of the present invention is to provide a compound having the formula (E)

[0048] [ka]

[0049] A method for industrially producing ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((((R)-1-aminoethyl)(hydroxy)phosphoryl)methyl)propanoyl)-L-alaninic acid, comprising the steps of:

[0050] [ka]

[0051] Step (1): synthesizing compound (A) by reacting (S)-1-phenylethylamine with a solution of hypophosphorous acid H3PO2 and acetaldehyde in the presence of a molar equivalent of concentrated hydrochloric acid, followed by treatment with propylene oxide; Step (2): synthesizing a compound of formula (B) by reacting a compound of formula (A) with a benzyl ester of (2-(4-biphenyl)methyl)acrylate; Step (3): synthesizing a compound of formula (C) by hydrogenolysis of a compound of formula (B) in the presence of Pd / C and protecting the resulting amine with a group P'; Step (4): Peptide coupling of the compound of formula (C) with the tert-butyl ester of (L)-alanine, followed by deprotection of the protecting group to synthesize the compound of formula (E). The present invention relates to a method, including

[0052] Process (1) The compound of formula (A) is mentioned in the publication by Hamilton et al., Tet. Lett., 1995, 36, 4451-4454, within the general synthesis of aminophosphonic acids, but is not listed as an example in the publication. Thus, to the inventors' knowledge, the compound of formula (A) has never been characterized before. The authors of the publication point out that for this particular example, the reaction conditions used "gave way to a dark solution from which it was not possible to isolate the product." The publication describes a hydrolysis-oxidation method for the synthesis of α-aminophosphonic acids, rather than aminophosphinic acids as in the present application. It is also pointed out that the removal of protecting groups on the amine functions of organophosphorous compounds by hydrogenolysis can be problematic.

[0053] The inventors have discovered in a surprising manner that the use of one equivalent of HCl during step (1a) makes it possible to avoid decomposition of the reaction mixture.

[0054] The presence of 1 equivalent of HCl, in the range of more or less than 0.1 equivalent, is an essential parameter for the synthesis of the present invention, in its absence decomposition is observed.

[0055] Step (1) of the method of the present invention comprises steps (1a) to (1c) as described above and illustrated in the following diagram.

[0056] [ka]

[0057] In application WO 2010 / 010106, the (1R)(1-benzyloxycarbonylamino-ethyl)-phosphinic) acid chiral precursor intended for reaction with the benzyl ester of (2-(4-biphenyl)methyl)acrylate is obtained in four steps via resolution of the racemic phosphinic acid in the presence of (R)(+)α-methylbenzylamine with an overall yield of 28% (see Example 1). The step of resolution of the racemate by recrystallization in the presence of (R)(+)α-methylbenzylamine is the notable cause of this low overall yield, since by definition 50% of the product corresponding to the undesired enantiomer is not recovered. In addition, the transfer of this type of chiral resolution to an industrial scale does not allow the yield to be improved.

[0058] In the present invention, in step (1a), chirality is directly induced at the beginning of synthesis by the starting reagent (S)-1-phenylethylamine. The (S)-1-phenylethylamine used in the present invention is a commercially available product (e.g., sold by Sigma-Aldrich) with a chiral purity of at least 98%, preferably 99%. Also, according to the present invention, chirality may be introduced using (S)-1-phenylethylamine with a chiral purity of at least 90%.

[0059] (S)-1-phenylethylamine is reacted in a polar and protic solvent with an aqueous solution of hypophosphorous acid, H3PO2, and acetaldehyde anhydride, i.e., chemical purity of 99% or greater, in the presence of a molar equivalent of hydrochloric acid relative to the amount of (S)-1-phenylethylamine.

[0060] The hydrochloric acid used in step (1a) advantageously corresponds to an aqueous solution of concentrated hydrochloric acid, which in particular makes it possible to avoid diluting the reaction mixture. Preferably, this solution is 37% by weight concentrated hydrochloric acid.

[0061] According to a preferred embodiment, the polar protic solvent in step (1a) is selected from among alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, and mixtures thereof. Preferably, the polar protic solvent is ethanol.

[0062] Preferably, step (1a) comprises, firstly, adding an advantageously concentrated hydrochloric acid solution to a solution of (S)-1-phenylethylamine in a polar and protic solvent as defined above, then, secondly, adding a solution of hypophosphorous acid to the mixture of (S)-1-phenylethylamine with hydrochloric acid, and finally, thirdly, adding acetaldehyde anhydride to the mixture of (S)-1-phenylethylamine, hydrochloric acid and hypophosphorous acid.

[0063] Advantageously, the aqueous hypophosphorous acid solution is a 50% by weight solution. Advantageously, the hypophosphorous acid is added in an amount comprised between 1 and 2 equivalents, preferably between 1.1 and 1.5 equivalents, more preferably 1.1 equivalents, relative to the (S)-1-phenylethylamine.

[0064] Acetaldehyde is preferably added in an amount comprised between 1 and 2 equivalents, preferably between 1.2 and 1.5 equivalents, more preferably 1.2 equivalents, relative to (S)-1-phenylethylamine. Typically, acetaldehyde anhydride is used.

[0065] In an advantageous embodiment, the solution of (S)-1-phenylethylamine is at a temperature comprised between -5°C and 5°C, preferably 0°C, during the addition of the concentrated hydrochloric acid solution and the hypophosphorous acid solution.

[0066] The resulting reaction mixture is stirred for a sufficient time to ensure a conversion of (S)-1-phenylethylamine of at least 90%. The monitoring of the reaction is ensured, in particular by HPLC. Preferably, this time is comprised between 1 and 8 hours, preferably between 3 and 6 hours, more preferably between 3 and 4 hours. The stirring is advantageously carried out at a temperature in the range of 5° C. above or below the boiling temperature of the solvent used.

[0067] Step (1a) is preferably carried out under an inert atmosphere, such as under a nitrogen or argon atmosphere.

[0068] In step (1b), propylene oxide is added to the reaction mixture resulting from step (1a). Step (1b) therefore typically comprises the following sequential steps: (1b.1) adding propylene oxide to the reaction mixture resulting from step (1a) to obtain a suspension; (1b.2) agitating the suspension resulting from step (1b.1); (1b.3) recovering the solids by filtering the suspension resulting from step (1b.2). Includes.

[0069] Propylene oxide is advantageously added in an amount comprised between 1 and 4 equivalents, preferably between 1.5 and 3 equivalents, more preferably 2 equivalents, relative to (S)-1-phenylethylamine. This addition is preferably carried out at a temperature comprised between 0° C. and 15° C., in particular at 10° C. The resulting mixture is typically stirred, in particular at room temperature, for a time comprised between 5 and 25 hours, preferably between 8 and 18 hours, in particular between 10 and 14 hours.

[0070] At the end of step (1b), the solid is recovered by filtration. The solid is then crystallized by suspending it in a polar protic solvent. Typically, the polar protic solvent is the same solvent as that used in step (1a).

[0071] Advantageously, the crystallization step (1c) comprises the following successive steps: (1c.1) diluting the solid material resulting from step (1b) in a polar and protic solvent, preferentially chosen among alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, and mixtures thereof, advantageously in ethanol, (1c.2) cooling the mixture resulting from step (1c.1) to a temperature comprised between 10° C. and 20° C.; (1c.3) recovering compound (A) after filtration and drying, in particular under vacuum Includes.

[0072] In certain embodiments, compound (A) is directly recovered by filtration at the end of step (1b) without the need for step (1c).

[0073] In another embodiment, step (1c) is optionally repeated, in particular once.

[0074] In another particular embodiment, the solid from step (1b) is washed with a polar and protic solvent and then dried, in particular under vacuum, to obtain a first fraction of the compound of formula (A). According to this embodiment, the filtrate from the filtration of step (1b) is concentrated, in particular under vacuum, to obtain a wet slurry, which itself is crystallized according to steps (1c.1) to (1c.3) described above.

[0075] In comparison with the method described in WO 2010 / 010106, in which the chiral precursor (1R)(1-benzyloxycarbonylamino-ethyl)-phosphinic) acid, intended for reaction with the benzyl ester of (2-(4-biphenyl)methyl)acrylate, is obtained after four reaction steps with an overall yield of 28%, according to the present invention the chiral precursor derivative of the phosphinic acid, intended for reaction with the benzyl ester of (2-(4-biphenyl)methyl)acrylate, is obtained in an average yield of 38 to 40% in the reaction.

[0076] The compound of formula (A) obtained at the end of step (1) has an optical purity (1R / 1S) of greater than 95 / 5, preferably greater than 96 / 4, more preferably greater than 97 / 3, even more preferably greater than 98 / 2, even more preferably greater than 99 / 1.

[0077] Process (2) Step (2) of the method of the present invention comprises steps (2a) and (2b) as described above and illustrated in the following diagram.

[0078] [ka]

[0079] Thus, in step (2a), the compound of formula (A) resulting from step (1) is reacted with the benzyl ester of (2-(4-biphenyl)methyl)acrylate in the presence of a source of trimethylsilyl groups. Advantageously, this source of trimethylsilyl groups is selected from among N,O-bis(trimethylsilyl)acetamide (BSA), TMS chloride (TMSCl), TMS triflate (TMSOTf) and hexamethyldisilazane (HMDS), preferably the source of trimethylsilyl groups is N,O-bis(trimethylsilyl)acetamide (BSA). The source of trimethylsilyl groups is one that allows the introduction of TMS groups on the secondary amine and hydroxyl functions of the compound of formula (A) such that the phosphorus atom is the only atom that reacts with the acrylate function of the benzyl ester of (2-(4-biphenyl)methyl)acrylate.

[0080] The benzyl ester of (2-(4-biphenyl)methyl)acrylate is obtained according to the method described in application WO 2010 / 010106 (see Example 2), using the protocol described in Organic Synthesis Coll., volume 3, page 337.

[0081] Preferably, step (2a) comprises firstly mixing the compound of formula (A) with the benzyl ester of (2-(4-biphenyl)methyl)acrylate and then secondly adding to said mixture a source of trimethylsilyl groups.

[0082] Advantageously, the source of trimethylsilyl groups is added in an amount comprised between 2 and 6 equivalents, preferably between 3 and 4.5 equivalents, more preferably 3.2 equivalents, relative to the compound of formula (A). Thus, according to the present invention, the amount of source of trimethylsilyl groups used, typically BSA, is limited, which is advantageous in terms of costs and removal of large amounts of unreacted reagents or impurities that arise in such amounts, unlike application WO 2010 / 010106, in which BSA is used as a solvent and therefore in large excess.

[0083] The benzyl ester of (2-(4-biphenyl)methyl)acrylate is preferably added in an amount comprised between 1 and 2 equivalents, preferably between 1 and 1.5 equivalents, more preferably 1 equivalent, relative to the compound of formula (A).

[0084] The reaction mixture comprising the compound of formula (A), the benzyl ester of (2-(4-biphenyl)methyl)acrylate and the source of trimethylsilyl groups is stirred for a sufficient time to ensure a conversion of the compound of formula (A) of at least 90%. The monitoring of the reaction is ensured, in particular by HPLC. Preferably, this time is comprised between 1 and 8 hours, preferably between 3 and 6 hours and more preferably between 3 and 4 hours. Said stirring is advantageously carried out at a temperature comprised between 40° C. and 120° C., preferably between 60° C. and 100° C. and more preferably between 75° C. and 85° C.

[0085] Step (2a) is preferably carried out under an inert atmosphere, such as under a nitrogen or argon atmosphere.

[0086] The compound of formula (B) is then recovered during step (2b).

[0087] According to a first alternative of the invention, step (2b) corresponds to crystallization step (2b.1). According to this alternative, step (2b.1) therefore advantageously follows directly after step (2a). In this first alternative, step (2b.2) is not carried out.

[0088] The crystallization step (2b.1) typically comprises the following sequential steps: (2b.1.1) cooling the reaction mixture from step (2a) to a temperature comprised between 20° C. and 40° C.; (2b.1.2) diluting the reaction mixture with a mixture of a non-polar aprotic solvent and water to form a suspension; (2b.1.3) recovering the compound of formula (B) by filtration of the suspension resulting from step (2b.1.2) and drying, in particular under vacuum. Includes.

[0089] Thus, according to this alternative, the compound of formula (B) is crystallized in a mixture of a non-polar aprotic solvent and water. The non-polar aprotic solvent is in particular selected from among hydrocarbons such as hexane, heptane, ethers such as diethyl ether, diisopropyl ether, methyl-tert-butyl ether (MTBE) and tetrahydrofuran (THF), and mixtures thereof. In particular, the non-polar aprotic solvent is MTBE. The crystallization solvent of step (2b.1.2) is therefore preferably a mixture of MTBE / water, in particular in a ratio of 5 / 3.

[0090] The presence of water in the reaction mixture allows, among other things, the deprotection of the TMS function. Before the precipitation step, compound (B) in solution is not enriched or is slightly enriched in the diastereoisomer (1R, 2S). The ratio of diastereoisomers (1R, 2S / 1R, 2R) at carbon 2 is: 13 For example, 60 / 40 as measured by P NMR.

[0091] During step (2b.1.2), the reaction mixture after dilution in the mixture of non-polar aprotic solvent and polar solvent is stirred for a sufficient time to precipitate compound (B), which is typically comprised between 2 hours and 24 hours, preferably 12 hours.

[0092] Under the conditions described, the crystallization of step (2b.1.2) is diastereoselective, meaning that the desired diastereoisomer with the configuration (1R, 2S) precipitates in a predominant manner compared to the diastereoisomer (1R, 2R). Thus, the compound of formula (B) obtained at the end of step (2) has predominantly the configuration (1R, 2S).

[0093] "Predominantly" or "predominantly manner" is understood in the sense of the present invention to mean that the diastereoisomer (1R,2S) is obtained in a proportion strictly greater than 50% compared to the diastereoisomer (1R,2R).

[0094] According to a first alternative of the present invention, the compound of formula (B) resulting from step (2b.1) has an optical purity at carbon 2 (2S / 2R) of greater than 95 / 5, preferably greater than 96 / 4, more preferably greater than 97 / 3, even more preferably greater than 98 / 2, even more preferably greater than 99 / 1.

[0095] According to the present invention, the compound of formula (B) resulting from the reaction of (2-(4-biphenyl)methyl)acrylate with the benzyl ester is obtained in an average yield of 54%. Taking into account the diastereoisomeric ratio (2S / 2R) at carbon 2 of around 60 / 40 obtained at the end of step (2a), the average yield of the crystallization step (2b.1) is around 90%, compared to 79% for the step of crystallization of the compound resulting from the reaction of (2-(4-biphenyl)methyl)acrylate with the benzyl ester described in application WO 2010 / 010106 (see example 3, step 1).

[0096] According to a second alternative of the invention, step (2b) corresponds to step (2b.2). Step (2b.2) therefore advantageously follows directly after step (2a). In this second alternative, step (2b.1) is not carried out.

[0097] Step (2b.2) typically comprises the following sequential steps: (2b.2.1) evaporating the reaction mixture from step (2a) and recovering the solids; (2b.2.2) triturating the solid from step (2b.2.1) in acetone, filtering, and evaporating to recover the compound of formula (B) in the filtrate. Includes.

[0098] Typically, the solid resulting from step (2b.2.1) corresponds to the so-called "native" compound of formula (B), i.e. has an optical purity at the 2-carbon position (2S / 2R) advantageously strictly greater than 50 / 50 and less than or equal to 95 / 5, typically comprised between 51 / 49 and 70 / 30, in particular 57 / 43.

[0099] Step (2b.2.2) corresponds to a step of diastereoisomeric enrichment of the compound of formula (B).

[0100] According to a preferred embodiment, the trituration of step (2b.2.2) is carried out for a period comprised between 30 minutes and 2 hours, typically 1 hour, and the temperature of said step is in particular equal to room temperature.

[0101] During this trituration step, the diastereoisomer with the (1R,2R) configuration precipitates in a predominant manner and the desired diastereoisomer with the (1R,2S) configuration is recovered in a predominant manner in the filtrate.

[0102] Typically, the compound of formula (B) obtained in the filtrate at the end of step (2b.2.2) has an optical purity at the 2-carbon position (2S / 2R) comprised between 70 / 30 and 90 / 10, preferably between 80 / 20 and 90 / 10, in particular 81 / 19.

[0103] Process 3 Step 3 of the method of the present invention comprises steps (3a) and (3b) as described above and in the diagram below.

[0104] [ka]

[0105] Step (3a) consists in carrying out hydrogenolysis in the presence of palladium on carbon (Pd / C) to enable the deprotection of the benzyl and 1-phenylethyl groups present on the compound of formula (B). In application WO 2010 / 010106, the deprotection of the benzyl and carboxybenzyl groups of the benzyl ester of 3-[(2-benzyloxycarbonyl-3-biphenyl-4-yl-propyl)-hydroxy-phosphinoyl]butyric acid is carried out by saponification in the presence of a large amount of sodium hydroxide (see example 3, step 2). However, this saponification is difficult to carry out on an industrial scale, since the large amount of benzyl alcohol produced creates a triphasic medium, making the isolation of the reaction intermediates difficult, and can result in the production of large amounts of impurities.

[0106] According to the present invention, deprotection by hydrogenolysis does not produce benzylic alcohols but by-products such as toluene and ethylbenzene that can be easily removed by evaporation under reduced pressure and therefore proves more suitable for industrial scale synthesis.

[0107] The sequential deprotection of the benzyl and 1-phenylethyl groups according to the present invention is shown in the following diagram.

[0108] [ka]

[0109] where X + represents the counter ion derived from the base used.

[0110] Advantageously, step (3a) comprises the following sequential steps: (3a.1) preparing a suspension of a compound of formula (B) in a protic solvent or a mixture of protic solvents; (3a.2) adding a base to the suspension prepared in step (3a.1); (3a.3) adding 10% by weight of Pd / C relative to the weight of the compound of formula (B) to the suspension resulting from step (3a.2) and purging the resulting reaction mixture with H2; (3a.4) filtering and concentrating the reaction mixture Includes.

[0111] According to a preferred embodiment, step (3a.1) is carried out in a protic solvent selected from among water, acetic acid, alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and tert-butanol, and mixtures thereof. Preferably, the protic solvent is a water / alcohol mixture, in particular water / ethanol.

[0112] Advantageously, the base in step (3a.2) is selected from among triethylamine, trimethylamine, diisopropylethylamine, sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), barium dihydroxide (Ba(OH)2), calcium dihydroxide (Ca(OH)2) and caesium dihydroxide (Cs(OH)2), preferably the base is sodium hydroxide, in particular 1 N sodium hydroxide.

[0113] According to a preferred embodiment, during the addition of said strong base, the suspension resulting from step (3a.1) is at a temperature comprised between -10°C and 10°C, preferably between -5°C and 5°C, more preferably at 0°C.

[0114] The strong base is advantageously added to the suspension resulting from step (3a.1) in an amount comprised between 1 and 2 equivalents, preferably between 1 and 1.5 equivalents, and more preferably 1 equivalent, relative to the compound of formula (B).

[0115] The mixture resulting from step (3a.2) is typically stirred at room temperature for a period sufficient to observe complete solubilization, in particular comprised between 1 hour and 5 hours.

[0116] After adding Pd / C to the reaction mixture, the mixture is advantageously purged with nitrogen or argon before being purged with H2.

[0117] According to an embodiment, the reaction mixture resulting from step (3a.3) is stirred for a time comprised between 15 and 30 hours, preferably between 18 and 25 hours, more preferably for 18 hours, at a temperature comprised between 15° C. and 40° C., preferably between 20° C. and 30° C. This stirring is typically carried out under a pressure of 1 bar of H2.

[0118] In certain embodiments, stirring of the reaction mixture resulting from step (3a.3) is stopped after a time sufficient to deprotect the benzyl group but before deprotection of the phenylethyl group occurs, in which case the amine functionality remains protected by the phenylethyl group and step (3b) is not required.

[0119] During step (3a.4), the reaction mixture is filtered to remove Pd / C, and the filtrate is then concentrated, for example under vacuum, to remove some of the solvent, particularly the alcohol.

[0120] It has been reported in the literature that phosphinic acids are Pd catalyst poisons, for example in the publication by Baylis et al., J. Chem. Soc., Perkin trans. I, 1984, pp. 2846-2853. For this reason, it is necessary to use large amounts of Pd / C, as described in WO 2010 / 010106 for the synthesis of Example 4 (PL265), where 50% by weight of 10% Pd / C is used. Such large amounts can lead to hydrogenation of the PC bond. In the present case, only 10% by weight of Pd / C can be used by controlling the pH to basic using a base, as described above for step (3a.2) for the synthesis of the compound of formula (C).

[0121] Step (3b) consists in protecting the primary amine function present on the reaction intermediate resulting from step (3a) using a protecting group denoted P', said protection being carried out according to methods known to those skilled in the art.

[0122] According to a preferred embodiment, the protection step (3b) is carried out in a basic medium, preferably by adding a strong base such as NaOH, LiOH, KOH, Ba(OH)2, Ca(OH)2 or CsOH. In particular, the pH of the reaction is comprised between 10 and 11. A too acidic pH can lead to the formation of polar impurities, whereas a pH above 11 leads to the decomposition of the reagent, making it possible to introduce the protecting group P'.

[0123] Advantageously, the group P' is selected from the group consisting of the benzyloxycarbonyl (CBz) group and the tert-butoxycarbonyl (Boc) group, which have the following formulae (Ca) and (Cb), respectively:

[0124] [ka]

[0125] The CBz group is especially introduced on the compound of formula (B) by using the corresponding chloride CBzCl. The Boc group is especially introduced on the compound of formula (B) by using the anhydride BocO.

[0126] According to the invention, the compound of formula (C) is obtained in a yield comprised between 50% and 85%. In particular, the compound of formula (Ca) is obtained in an average yield of 73% and the compound of formula (Cb) in an average yield of 84%.

[0127] According to the first alternative of the invention as described above, i.e. according to this first alternative, steps (3a) and (3b) as described above are carried out, using in step (3a) a compound of formula (B) obtained following step (2b.1) and having an optical purity (2S / 2R) of more than 95 / 5. According to this first alternative, the compound of formula (C) in configuration (1R, 2S), obtained immediately after step (3b), has an optical purity (2S / 2R) at carbon 2 of more than 95 / 5, preferably more than 96 / 4, more preferably more than 97 / 3, even more preferably more than 98 / 2, even more preferably more than 99 / 1.

[0128] According to this first alternative form of the invention, the compound of formula (C) is obtained in particular in a yield comprised between 70% and 85%, in particular the compound of formula (Ca) is obtained in an average yield of 73% and the compound of formula (Cb) in an average yield of 84%.

[0129] According to this first alternative, the compound of formula (C) is recovered at the end of step (3b) and used directly in the subsequent step (4) without purification and without any other intermediate steps.

[0130] According to a second alternative of the invention, steps (3a) and (3b) as described above are carried out using in step (3a) the compound of formula (B) obtained at the end of step (2b.2) and having an optical purity (2S / 2R) at carbon 2 strictly greater than 50 / 50 and less than 95 / 5, typically comprised between 70 / 30 and 90 / 10, in particular 81 / 19.

[0131] According to this second alternative, an additional step of diastereomeric enrichment of the compound of formula (C) is carried out following step (3b). The process of the invention therefore comprises, immediately after step (3b), the additional step (3c): (3c) triturating the compound of formula (C) in a mixture of water / MTBE followed by filtering and drying; may also include

[0132] According to a preferred embodiment, the trituration of step (3c) is carried out for a period comprised between 30 minutes and 2 hours, typically 1 hour, and the temperature of said step is in particular equal to room temperature.

[0133] The volume ratio of the water / MTBE mixture during step (3c) is typically comprised between 1 / 5 and 1 / 1, preferably 3 / 5.

[0134] Typically, according to the second alternative of the invention, the compound of formula (C) obtained at the end of step (3c) has an optical purity (2S / 2R) at carbon 2 of between 80 / 20 and 99 / 1, preferably between 90 / 10 and 95 / 5, and in particular 93 / 7. According to this second alternative of the invention, the compound of formula (C) is obtained in a yield of the order of 53%.

[0135] Process 4 Step 4 of the method of the present invention comprises steps (4a) and (4b) as described above and in the diagram below.

[0136] [ka]

[0137] Advantageously, step (4a) comprises the following sequential steps: (4a.1) adding tert-butyl ester of (L)-alanine and a peptide coupling agent to a solution containing a compound of formula (C) dissolved in DMF or a THF / DMF mixture; (4a.2) adding a base to the reaction mixture resulting from step (4a.1); (4a.3) The following formula (D)

[0138] [ka]

[0139] in which P' is as defined above or corresponds to a phenylethyl group. and recovering the compound. Includes.

[0140] The peptide coupling agent introduced in step (4a.1) is typically selected from among TBTU, HATU, EDC, HOBt, BOP, PyBOP, DCC, and combinations thereof.

[0141] Step (4a.1) is preferably carried out at room temperature. During step (4a.1), if a mixture of THF / DMF is used, the mixture of THF / DMF is preferably a 1 / 1 volume ratio mixture.

[0142] The base introduced in step (4a.2) is preferably selected from among triethylamine, diisopropylethylamine (DIPEA) and 2,2,6,6-tetramethylpiperidine, preferably the base is DIPEA.

[0143] According to a preferred embodiment, during the addition of the base in step (4a.2), the reaction mixture resulting from step (4a.1) is at a temperature comprised between 0° C. and 15° C., preferably between 5° C. and 10° C. Said temperature is maintained during the addition of the base, which is generally exothermic.

[0144] According to an advantageous embodiment, the reaction mixture resulting from step (4a.2) is stirred for a sufficient time to obtain a conversion of the compound of formula (C) of at least 95%. The monitoring of the reaction is ensured, in particular by HPLC. Preferably, this time is comprised between 30 minutes and 2 hours, preferably between 30 minutes and 1 hour, more preferably 45 minutes, at a temperature comprised between 0° C. and 15° C., preferably between 5° C. and 10° C.

[0145] The compound of formula (D) is recovered following procedures of acid-base washing, extraction into an organic phase, and filtration, known to those skilled in the art.

[0146] In a preferred embodiment, the compound of formula (D) is selected from the group consisting of the following compounds (Da) and (Db):

[0147] [ka]

[0148] The compound of formula (D) is obtained in a yield comprised between 60% and 90%.

[0149] The deprotection of group P', step (4b), is preferably carried out under an inert atmosphere, for example under a nitrogen or argon atmosphere.

[0150] In certain embodiments, when P' is a CBz group, step (4b) comprises the following sequential steps: (4b.1) The following formula

[0151] [ka]

[0152] reacting compound (Da) with HBr in acetic acid; (4b.2) then precipitation using a solvent selected from ethyl acetate, isopropyl acetate, ether, and mixtures thereof, and recovering the compound of formula (E) by filtration. Includes.

[0153] In a preferred mode, step (4b.1) comprises the following sequential steps: (4b.1.1) mixing a compound of formula (Da) with acetic acid; (4b.1.2) adding hydrobromic acid in the form of a solution of HBr in acetic acid; (4b.1.3) stirring the resulting mixture for a sufficient time to achieve at least 95% conversion of the compound of formula (Da). Includes.

[0154] Hydrobromic acid HBr is preferably added in an amount comprised between 6 and 10 equivalents, preferably between 6 and 8 equivalents, more preferably 6 equivalents, relative to compound (Da). If the amount of hydrobromic acid is more than 10 equivalents, it leads to partial racemization of the product upon concentration. A minimum of 6 equivalents is required so that deprotection is complete. By comparison, in a similar deprotection step using HBr in acetic acid in application WO 2010 / 010106 (see Example 3, step 2), 28 equivalents of HBr were used. The amount used in the present invention in particular allows the residual acid to be more easily removed, especially by evaporation.

[0155] In a preferred embodiment, during the addition of hydrobromic acid, the mixture resulting from step (4b.1.1) is at a temperature comprised between 5° C. and 20° C., preferably between 10° C. and 15° C. During the addition of HBr and during step (4b.1.3), the temperature is maintained below 20° C., preferably between 15° C. and 20° C. Temperatures above 20° C. may lead to partial racemization of the resulting product.

[0156] The reaction mixture resulting from step (4b.1.2) is stirred for a sufficient time to ensure that the conversion of (S)-1-phenylethylamine is at least 95%. The monitoring of the reaction is ensured, in particular by HPLC. Preferably, this time is comprised between 2 and 8 hours, preferably between 3 and 6 hours, more preferably between 5 and 6 hours.

[0157] The ether in step (4b.2) is preferably selected from among diisopropyl ether, tetrahydrofuran, methyl-tert-butyl ether, dioxane, diethyl ether, petroleum ether, and mixtures thereof.

[0158] Preferably, the solvent of step (4b.2) corresponds to diisopropyl ether.

[0159] In another particular embodiment, when P' is a Boc group, step (4b) comprises the following sequential steps: (4b.1') The following formula

[0160] [ka]

[0161] reacting compound (Db) with formic acid to obtain an oily product; (4b.2') triturating the oil resulting from step (4b.1') in a non-polar aprotic solvent and recovering the compound of formula (E) by filtration. Includes.

[0162] In a preferred mode, step (4b.1') comprises the following sequential steps: (4b.1'.1) mixing a compound of formula (Db) with formic acid; (4b.1'.2) stirring the resulting solution for a time comprised between 1 hour and 4 hours, preferably 2 hours, at a temperature comprised between 40°C and 60°C, preferably at 50°C, (4b.1'.3) concentrating the solution, especially under vacuum, until an oil is obtained Includes.

[0163] In step (4b.1'.1), formic acid is preferably added in a proportion comprised between 20 and 40 equivalents, preferably between 20 and 30 equivalents, more preferably 26 equivalents, relative to the compound of formula (Db). The formic acid used is typically an 88% by volume solution of formic acid in water.

[0164] Formic acid has the advantage that it is not too acidic or corrosive and can be easily removed, making it particularly suitable for industrial-scale synthesis.

[0165] Advantageously, the apolar aprotic solvent of step (4b.2') is chosen from among hexane, heptane, diisopropyl ether, MTBE and mixtures thereof, and preferably the apolar aprotic solvent is MTBE.

[0166] The compound of formula (E) is typically obtained in a yield comprised between 90% and 95%.

[0167] According to a first alternative of the invention, involving carrying out step (2b.1) as described above, and not carrying out steps (2b.2) and (3c), in which steps (4a) and (4b) as described above are carried out, using in step (4a) a compound of formula (C) derived from step (3b) and having an optical purity (2S / 2R) at carbon 2 of more than 95 / 5, preferably more than 96 / 4, more preferably more than 97 / 3, even more preferably more than 98 / 2, even more preferably more than 99 / 1. According to this first alternative, the compound of formula (D) in the configuration (1R, 2S, L-Ala) has an optical purity (2S / 2R) at the 2-position carbon of more than 95 / 5, preferably more than 96 / 4, more preferably more than 97 / 3, even more preferably more than 98 / 2, even more preferably more than 99 / 1, and the compound of formula (E) in the configuration (1R, 2S, L-Ala) also has an optical purity (2S / 2R) at the 2-position carbon of more than 95 / 5, preferably more than 96 / 4, more preferably more than 97 / 3, even more preferably more than 98 / 2, even more preferably more than 99 / 1.

[0168] According to a second alternative of the invention, which involves carrying out step (2b.2) and an additional step (3c) as described above, whereby step (2b.1) is not carried out, steps (4a) and (4b) as described above are carried out using in step (4a) a compound of formula (C) resulting from step (3c) and having an optical purity (2S / 2R) at carbon 2 of more than 50 / 50 and less than or equal to 95 / 5, preferably comprised between 90 / 10 and 95 / 5, in particular 93 / 7. According to this first alternative, the compound of formula (D) in the configuration (1R, 2S, L-Ala) has an optical purity comprised between 80 / 20 and 99 / 1, preferably comprised between 90 / 10 and 95 / 5.

[0169] According to this second alternative, an additional step of diastereomeric enrichment of the compound of formula (E) is carried out following step (4b). The process of the invention therefore comprises, immediately after step (4b), the additional step (4c) of: (4c) triturating the compound of formula (E) in dichloromethane; may also include

[0170] According to a preferred embodiment, the trituration of step (4c) is carried out for a period comprised between 30 minutes and 2 hours, typically 1 hour, and the temperature of said step is in particular equal to room temperature.

[0171] Typically, the compound of formula (E) obtained at the end of step (4c) has an optical purity at carbon 2 (2S / 2R) comprised between 90 / 10 and 99 / 1, in particular 94 / 6.

[0172] Methods for preparing compounds of formula (I) Another object of the present invention is to provide a compound according to the present invention having the following formula (I):

[0173] [ka]

[0174] A method for industrially producing disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alanine, comprising the steps of:

[0175] [ka]

[0176] Steps (1) to (4) as described above; Step (5): reacting the compound of formula (E) with an acyloxyalkyl N-hydroxysuccinimide in the presence of a base to synthesize the compound of formula (F); Step (6): Recovering the compound of formula (I) by precipitation in a non-polar aprotic solvent in the presence of a sodium salt of a weak base. The present invention relates to a method comprising the steps of:

[0177] Thus, the process for the industrial manufacture of the compound of formula (I) comprises the successive steps (1) to (4) as defined above, according to one or the other of the first and second alternatives described above, as well as steps (5) and (6) which are carried out immediately after step (4), as reported in detail below.

[0178] Process 5 Step 5 according to the present invention involves reacting a compound of formula (E) with an acyloxyalkyl N-hydroxysuccinimide in the presence of a base to obtain a compound of formula (F) as depicted in the diagram below.

[0179] [ka]

[0180] Step (5) advantageously comprises the following sequential steps: (5a) reacting a compound of formula (E) with an acyloxyalkyl N-hydroxysuccinimide in the presence of a base in a polar aprotic solvent; (5b) crystallizing using an aprotic non-polar solvent and recovering the compound of formula (F) by filtration. Includes.

[0181] In a preferred mode, step (5a) comprises the following sequential steps: (5a.1) dissolving a compound of formula (E) in a polar aprotic solvent; (5a.2) adding an acyloxyalkyl N-hydroxysuccinimide to the solution resulting from step (5a.1); (5a.3) adding a base to the solution resulting from step (5a.2). Includes.

[0182] The reaction of the compound of formula (E) with acyloxyalkyl N-hydroxysuccinimide (CAS 860035-3-10-5) produces N-hydroxysuccinimide as a by-product, which can be easily removed by washing with water. The introduction of the acyloxyalkyl group does not require purification on a silica column, unlike the synthesis described in application WO 2010 / 010106, which requires purification on silica gel due to the production of 4-nitrophenol, and is therefore hardly suitable for industrial-scale synthesis.

[0183] In step (5a.1), the dissolution of the compound of formula (E) is preferably carried out at room temperature.

[0184] The polar aprotic solvent is in particular selected from among DMF, DMSO, acetone and ethyl acetate, preferably the polar aprotic solvent is DMF.

[0185] Advantageously, the acyloxyalkyl N-hydroxysuccinimide is added to the solution resulting from step (5a.1) in an amount comprised between 1 and 2 equivalents, preferably between 1 and 1.5 equivalents, and more preferably 1 equivalent, relative to the compound of formula (E).

[0186] Preferably, during the addition of the acyloxyalkyl N-hydroxysuccinimide, the solution resulting from step (5a.1) is at a temperature comprised between 0°C and 15°C, preferably between 5°C and 10°C.

[0187] The base introduced during step (5a.3) is notably chosen among triethylamine, diisopropylethylamine (DIPEA) and 2,2,6,6-tetramethylpiperidine, especially triethylamine.

[0188] During the addition of the base, the temperature of the reaction mixture is maintained below 15°C, preferably between 10°C and 15°C.

[0189] Preferably, the base is added to the solution resulting from step (5a.2) in an amount comprised between 1 and 4 equivalents, preferably between 2 and 3 equivalents, in particular between 2 and 2.5 equivalents, compared to the compound of formula (E).

[0190] The reaction mixture resulting from step (5a.3) is stirred for a sufficient time to ensure a conversion of the compound of formula (F) of at least 95%. The monitoring of the reaction is in particular ensured by HPLC. Preferably, this time is comprised between 1 h and 8 h, preferably between 4 h and 6 h, more preferably between 4 h and 5 h. Said stirring is advantageously carried out at a temperature comprised between 10° C. and 20° C., preferably between 15° C. and 20° C.

[0191] Operations of acid-base washing, in particular acid washing, and extraction in the organic phase, known to those skilled in the art, may be carried out between steps (5a) and (5b).

[0192] The non-polar aprotic solvent used for the crystallization in step (5b) is typically selected from among hydrocarbons such as hexane, heptane, ethers such as diethyl ether, diisopropyl ether, methyl-tert-butyl ether (MTBE) and tetrahydrofuran (THF), and mixtures thereof. In particular, the non-polar aprotic solvent is diisopropyl ether.

[0193] Typically, the crystallization is carried out at room temperature.

[0194] In a particularly advantageous manner, prior to step (5b), it is possible to initiate crystallization by adding a polar aprotic solvent, such as DMF, DMSO, acetone, ethyl acetate, isopropyl acetate and mixtures thereof, preferably ethyl acetate or isopropyl acetate, especially isopropyl acetate, to the mixture resulting from step (5b). According to this embodiment, after stirring the reaction mixture for a period comprised between 30 minutes and 1 hour, preferably 30 minutes, typically at room temperature, said polar aprotic solvent is removed to the extent of 80%, more or less than 5%, for example by concentrating under vacuum, and the resulting residue is mixed with a non-polar aprotic crystallization solvent as defined above.

[0195] The compound of formula (F) in the configuration (1R, 2S, L-Ala) advantageously has an optical purity at the 2-carbon position (2S / 2R) of 95 / 5 or more, preferably greater than 96 / 4, more preferably greater than 97 / 3, even more preferably greater than 98 / 2, even more preferably greater than 99 / 1.

[0196] The compound of formula (F) is typically obtained in an average yield of 89%.

[0197] Process (6) Step (6) corresponds to the salification of the compound of formula (F) with sodium to obtain the disodium salt of formula (I).

[0198] The sodium salt of a weak base serves to ionize the hydroxyl functional group and provide the sodium counterion to give the salt of formula (I). The sodium salt of a weak base is preferably sodium bicarbonate.

[0199] Advantageously, the sodium salt of a weak base is added in an amount comprised between 2 equivalents and, more or less, 0.2 equivalents relative to the compound of formula (F).

[0200] According to a preferred embodiment, step (6) comprises the following sequential steps: (6a) dissolving the compound of formula (F) in a solvent that is miscible with water and has a low boiling point, such as, for example, an ether, in particular THF or dioxane, preferably THF; (6b) adding water and a sodium salt of a weak base to the solution resulting from step (6a); (6c) removing the solvent of step (6a), in particular by concentrating under vacuum; (6d) adding a non-polar aprotic solvent, which is useful for precipitating the compound of formula (I); (6e) recovering the compound of formula (I) by filtration and drying. Includes.

[0201] The mixture resulting from step (6b) is stirred for a period comprised in particular between 15 minutes and 1 hour, preferably for 30 minutes. When sodium bicarbonate is used as the sodium ion source, the mixture is stirred for a sufficient time to dissipate the gaseous emissions resulting from the addition of sodium bicarbonate, which arise from the formation of CO2 during the reaction of NaHCO3 with the compound of formula (F).

[0202] Preferably, step (6c) is followed by several THF addition-removal operations prior to step (6d) in order to remove water by azeotropic distillation.

[0203] Preferably, the non-polar aprotic solvent in step (6d) is selected from among ethers, in particular diisopropyl ether and diethyl ether, more preferably the non-polar aprotic solvent is diisopropyl ether.

[0204] In a preferred manner, step (6d) is carried out in two stages. First, 1 / 4 of the volume of the non-polar aprotic solvent is added to the residue resulting from step (6c), and then the resulting mixture is concentrated, especially under vacuum, to remove the organic phase. Secondly, the remaining 3 / 4 of the volume of the non-polar aprotic solvent is added to the residue resulting from the first concentration. The resulting suspension is typically stirred for a time comprised between 30 minutes and 2 hours, preferably for 1 hour, especially at room temperature, and then filtered.

[0205] The compound of formula (I) in the configuration (1R, 2S, L-Ala) advantageously has an optical purity at the 2-carbon position (2S / 2R) of 95 / 5 or more, preferably greater than 96 / 4, more preferably greater than 97 / 3, even more preferably greater than 98 / 2, even more preferably greater than 99 / 1.

[0206] The compound of formula (I) is typically obtained in an average yield from step (6) of 91%.

[0207] Thus, according to the invention, the compounds of formula (I) are obtained by precipitation in an aprotic apolar solvent, rather than by lyophilization, as described in WO 2010 / 010106, which is hardly suitable for synthesis on an industrial scale.

[0208] Diastereoisomerically enriched methods The present invention also relates to a process for diastereoisomerically enriching an intermediate in the industrial process for producing the compound of formula (E) of the present invention.

[0209] The diastereomeric enrichment method comprises carrying out diastereomeric enrichment of the compounds of formula (B), (C), and (E) when they have an optical purity (2S / 2R) at the 2-position carbon of 95 / 5 or less. To do so, in each of steps (2), (3), and (4) as described above, a trituration step is carried out in a suitable solvent for the compounds of formula (B), (C), and (E) when they have an optical purity (2S / 2R) at the 2-position carbon of 95 / 5 or less.

[0210] Thus, the process for preparing a compound of formula (E) with a diastereoisomeric enrichment according to the invention is carried out from the so-called "raw" compound of formula (B) as described above, which corresponds to a solid resulting from step (2b.2.1) described above and having an optical purity (2S / 2R) at carbon 2 of more than 50 / 50 and not more than 95 / 5, typically between 51 / 49 and 60 / 40, in particular 57 / 43, and which is followed by a diastereoisomeric enrichment process, comprising the following steps: (2b.2.2) triturating the solid from step (2b.2.1) in acetone, filtering and evaporating to recover the compound of formula (B) in the filtrate; (3c) triturating the compound of formula (C) in a mixture of water / MTBE according to step (3b) as described above, followed by filtering and drying; (4c) triturating the compound of formula (E) in dichloromethane, followed by filtration and drying, according to step (4b) as described above. Includes.

[0211] Typically, the compound of formula (B) obtained at the end of step (2b.2.2) has an optical purity at the 2-carbon position (2S / 2R) comprised between 70 / 30 and 90 / 10, preferably between 80 / 20 and 90 / 10, in particular 81 / 19.

[0212] Typically, the compound of formula (C) obtained at the end of step (3c) has an optical purity at carbon 2 (2S / 2R) comprised between 80 / 20 and 99 / 1, preferably between 90 / 10 and 95 / 5, in particular 93 / 7.

[0213] Typically, the compound of formula (E) obtained at the end of step (4c) has an optical purity at carbon 2 (2S / 2R) comprised between 90 / 10 and 99 / 1, in particular 94 / 6.

[0214] According to a preferred embodiment, the trituration of steps (2c), (3c) and (4c) is carried out for a period comprised between 30 minutes and 2 hours, typically 1 hour, the temperature of said steps being in particular equal to room temperature.

[0215] In the process for preparing a compound of formula (E) involving a diastereomeric enrichment process according to the present invention, step (2b.1) as described above is not performed and is replaced by step (2b.2).

[0216] These trituration steps (2b.2.2), (3c) and (4c) are not carried out if compound (B), compound (C) and compound (D) are obtained at the end of steps (2b), (3b) and (4b), respectively, with an optical purity at carbon 2 (2S / 2R) of greater than 95 / 5.

[0217] Compound of formula (B) The present invention also relates to a compound having the following formula (B) in the configuration (1R, 2S):

[0218] [ka]

[0219] The present invention also relates to compounds of the formula: EXAMPLES

[0220] The following examples are intended to illustrate the invention without, however, limiting it. The following abbreviations have been used: TLC Thin Layer Chromatography HPLC High Performance Liquid Chromatography DMSO Dimethyl sulfoxide eq. equivalent weight ESI Electrospray Ionization min NMR nuclear magnetic resonance TFA Trifluoroacetic acid

[0221] [1R-[(1S-phenylethyl)amino]ethyl]-phosphinic acid (Compound A) Concentrated HCl (8.14 g, 1 eq.) is added successively to an ice-cold solution of (S)-1-phenylethylamine (10 g, 82.5 mmol) in EtOH (40 mL, 4 vol.). After purging with N2, acetaldehyde anhydride (4.36 g, 1.2 eq.) is added. The mixture is heated to reflux at 80° C. After 3 h, the mixture is analyzed by HPLC, and if the conversion of the amine to compound (A) is less than 90%, 0.2 eq. of acetaldehyde is added and the mixture is refluxed again for 1 h. The solution is then cooled to 10° C., treated with propylene oxide (9.57 g, 2 eq.) and allowed to warm to room temperature.

[0222] The suspension is stirred overnight at 20° C. and then filtered. The solid is washed with EtOH (5 mL, 0.5 vol) and then dried under vacuum to give a white solid (1st crop, yield: 20.5%, 1R / 1S=98 / 2). The filtrate is diluted with iBuOAc (10 vol to form an azeotrope with water) and then concentrated to a thick white slurry, diluted with EtOH (4 vol) and stirred at 20° C. for 1 h. The 2nd crop is filtered, washed with EtOH (5 mL, 0.5 vol) and then dried to give a white solid (yield: 17.8%, 1R / 1S=92 / 8), giving an overall yield of 38-40% and an optical purity (1R / 1S) of >95 / 5. NMR (DMSO D6+TFA), 1 H (400 MHz): 1.27 (dd, 3H, CH3); 1.57 (d, 3H, NCHCH3); 3.06 (m,1H); 4.72 (m, 1H, NCH); 6.33 and 7.72 (2s, 1H, PH); 7.44 (m, 3H, aromatic) and 7.55 (m, 2H, aromatic). 31 P 19.91 (0.02 P); 20.89 (0.98 P).

[0223] [(1S)-1-[[(1R)-1-[[(2S)-3-benzyloxy-3-oxo-2-[(4-phenylphenyl)methyl]propyl]-hydroxy-phosphoryl]ethyl]amino]ethyl] compound (B) In a reactor purged with N2, N,O-bis(trimethylsilyl)acetamide (BSA) (10.67 g, 3.2 equiv.) is added to compound (A) (3.5 g, 16.4 mmol, 1 equiv.) and benzyl ester of (2-(4-biphenyl)methyl)acrylate (5.38 g, 1 equiv.). The thick suspension is heated to 40°C (minimal stirring capacity) to 80°C (completely solubilized at 75°C) and stirred for 3 h. The solution is analyzed by HPLC (>90 / 10 conversion), then cooled to 20-40°C and diluted with MTBE (20 vol.) and HO (3.5 mL, 12 equiv., exothermic reaction). A suspension forms within a few hours. It is stirred for a minimum of 2 to 3 h (preferably overnight to allow for slow precipitation). The suspension is filtered and dried to give a white solid of configuration (1R, 2S) (5.11 g, yield: 54%, (2S / 2R=96 / 4)). NMR (DMSO D6+TFA) 1H (400 MHz): d 1.24 (dd, 3H, C(2)CH3); 1.54 (d, 3H, NCHCH3); 1.91 and 2.18 (2 m, 2H, C(4)H2); 2.89 (m, 1H, C(2)H); 3.0 (m, 2H, C(5)CH2); 3.09 (m, 1H, C(5)H); 4.71 (m,1H, NCH); 5.0 (m, 2H, OCH2Bn); 7.15-7.66 (m, 19H, aromatic). 31 P 39.61 (0.96 P, 2S diastereoisomer) and 39.87 (0.04 P, 2R diastereoisomer).

[0224] (2S)-2-[[[(1R)-1-(benzyloxycarbonylamino)ethyl]-hydroxy-phosphoryl]methyl]-3-(4-phenylphenyl)propanoic acid (compound Ca) 1N NaOH (2.77 mL, 1 eq.) was added to an ice-bath cooled suspension of compound (B) (1.5 g, 2.77 mmol) in EtOH (22.5 mL, 15 vol.) and H2O (18 mL, 12 vol.) (pH monitored for reference purposes, below 11). The mixture was stirred at room temperature until complete solubilization. 10% Pd / C (0.15 g, 10% by weight with respect to compound (B), 50% wet) was added. The reaction mixture was purged with N2, followed by H2 (3 cycles of vacuum / N2, followed by 3 cycles of vacuum / H2) and stirred under 1 bar H2 at 20-30 °C for 18 h. The pH was recorded for reference (pH around 7-8). The reaction mixture was filtered through 0.45 μm and then partially concentrated to remove EtOH. 1N NaOH (2.77mL, 1eq, pH >10) is added, followed by CbzCl (0.472g, 1eq), followed by 1N NaOH (2.77mL, 1eq) and the mixture is stirred at room temperature for 2 hours. The reaction is quantified by HPLC and the compound after acid-base washing is used as is in the next step (0.975g, yield: 73%, (2S / 2R)=95 / 5). NMR (DMSO D6 +TFA) 1H (400 MHz) d 1.21 (dd, 3H, C(2)-CH3), 1.75 and 1.98 (2 m, 1H+1H, C(4)H2); 2.89-3.02 (m, 3H, C(5)H and C(5)-CH2); 3.76 (m, 1H, C(2)H); 5.03 (m, 2H, OCH2Bn); 7.25-7.63 (m, 15H, aromatics and NH). 31 P 45.04 (0.05 P, 2R diastereoisomer) and 45.70 (0.95 P, 2S diastereoisomer).

[0225] [(1R)-1-(benzyloxycarbonylamino)ethyl]-[(2S)-3-[[(1S)-2-tert-butoxy-1-methyl-2-oxo-ethyl]amino]-3-oxo-2-[(4-phenylphenyl)methyl]propyl]phosphinic acid (Compound Da) 1.685 kg of compound (Ca) in 8.4 L of DMF is stirred at room temperature (20-25° C.) until a clear solution is obtained, then 763 g (4.2 mol) of H-Ala-OtBu.HCl and 3372 g (10.5 mol) of TBTU are added at room temperature. The mixture is cooled to approximately 5° C. and 2263 g (17.5 mol) of DIEPA are added while maintaining the temperature at 5-10° C. After the addition, the mixture is stirred at 5-10° C. for 45 minutes. 8.4 L of ethyl acetate is added at 5° C., as well as 10 L of 1N aqueous HCl solution. The mixture is stirred at room temperature for 10 minutes. The aqueous phase is extracted with ethyl acetate (1×8.4 L), the organic phases are combined and washed with 10% aqueous NaHCO3 solution (3×6 L), 3 L of 1N HCl solution, and 3 L of brine. The product precipitated in the organic phase is heated with stirring in 8 L of ethyl acetate at 45-50° C. until a clear solution is obtained. After cooling it, the correct diastereoisomer is obtained by successive precipitations in the form of a white solid (1.314 kg) (yield: 62%, purity by HPLC 100%). NMR (DMSO D6 + TFA): 1H (400 MHz) d 1.17 (m, C(2)CH3, 3H); 1.22 (d, 3H, C(8)H3); 1.36 (s, 9H, tBu); 1.61 and 1.93 (2 m, 1H+1H, C(4)H2); 2.79 (m, 1H, C(5)H); 2.98 (m, 2H, C(5)CH2); 3.72 (m, 1H, C(2)H); 4,11 (m, 1H, C(8)H); 5,01 (m, 2H, OCH2Bn); 7.25-7.63 (m, 15H, aromatics and N(1)H) and 8.29 (d, 1H, N(7)H). 31 P 45.95 (0.96 P, 2S diastereoisomer) and 46.22 (0.04 P, 2R diastereoisomer).

[0226] ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((((R)-1-aminoethyl)(hydroxy)phosphoryl)methyl)propanoyl)-L-alaninic acid (Compound E (PL254.HBr)) 1250 g (2.054 moles) of compound (Da) are mixed with 2.5 L of acetic acid under a nitrogen stream. The mixture is stirred at room temperature (15-20° C.) until all solids are dissolved, then cooled to 10-15° C. and 2.99 kg (33%, 12.32 moles HBr) of HBr in acetic acid is added slowly while maintaining the temperature at 16-20° C. After addition over 5 hours, the mixture is concentrated under vacuum at 18-20° C. to remove approximately 400-500 mL of acetic acid, and 6 L of ethyl acetate is added, while monitoring the progress of the reaction by HPLC. The mixture is stirred at room temperature (15-20° C.) for 30 minutes, then filtered to isolate the solid product. It is washed with ethyl acetate (3 times 2 L) and diisopropyl ether (1 time 3 L), then dried overnight at 35° C. under air flow to give 950 g of solid product (yield: 92.7%, HPLC purity: 99.5%). NMR (DMSO D6 + TFA): 1H (400 MHz) d 1.22 (dd, 3H, C(2)CH3); 1.30 (d, 3H, C(8)H3); 1.64 and 2.19 (2 m, 1H+1H, C(4)H2); 2.74 (m, 1H, C(5)H); 3.06 (m, 2H, C(5)CH2); 3.26 (m, 1H, C(2)H); 4.23 (m, 1H, C(8)H); 7.36 (m, 3H, aromatic); 7.45 (m, 2H, aromatic); 7.60 (d, 2H, aromatic); 7.66 (d, 2H, aromatic); 7.70 (m, 9H, aromatic); 8.07 (br s, 3H, N(1)H3 + ) and 8.53 (d, 1H, N(9)H). 31 P 41.51 (0.98 P, 2S diastereoisomer) and 42.13 (0.02 P, 2R diastereoisomer). HPLC purity (254 nm, Kromasil C18. 250 mm × 4.6 mm, 5 μm), H2O (0.01% TFA)-CH3CN (0.01% TFA) 90 / 10 for 2 min, then 10 / 90 over 14 min, 10 / 90 for 4 min: 99.5%, t R 10.31 and 11.25 mins.

[0227] (2S)-2-[[[(1R)-1-(tert-butoxycarbonylamino)ethyl]-hydroxy-phosphoryl]methyl]-3-(4-phenylphenyl)propanoic acid (Compound Cb) 1N NaOH (2.2 mL, 1 eq.) is added to an ice-bath cooled suspension of compound (B) (1 g, 2.21 mmol, 2R / 2S 4 / 96) in EtOH (15 mL, 15 vol.) and H2O (12 mL, 12 vol.). The mixture is stirred at room temperature until complete solubilization. 10% Pd / C (0.15 g, 10% by weight with respect to compound (B), 50% wet) is added. The reaction mixture is purged with N2, followed by H2 (3 cycles of vacuum / N2, followed by 3 cycles of vacuum / H2) and stirred under 1 bar H2 at 20-30 °C for 18 h. The pH is recorded for reference (pH around 7-8). The reaction mixture is filtered through 0.45 μm. 1N NaOH (2.2 mL, 1 eq.), Boc2O (0.5 g, 1 eq.), followed by 1N NaOH (2.2 mL, 1 eq.) are added successively. The mixture is stirred at room temperature for 2 hours and then partially concentrated to remove EtOH. The aqueous phase is treated with 1N HCl (0.655 g, 3 eq.) until the pH is less than 1. The suspension is treated with iBuOAc (1.28 g, 5 eq.) and mixed for 2 hours to give a solid. The solid is filtered and then dried under reduced pressure to give compound (Cb) (0.837 g, 84%). NMR (DMSO D6+TFA): 1 H (400 MHz) d 1.17 (m, 3H, C(2)-CH3); 1.36 (s, 9H, tBu); 1.71 and 1.97 (2m, 1H+1H, C(4)H2); 2.9-3.1 (m, 3H, C(5)H and C(5)-CH2); 3.70 (m, 1H, C(2)H); 7.01 (d, 1H, NH); 7.27 (d, 2H, aromatic); 7.34 (m, 1H, aromatic); 7.45 (m, 2H, aromatic); 7.57 (d, 2H, aromatic) and 7.64 (d, 2H, aromatic). 31 P 46.4 (only 2S diastereoisomer detected).

[0228] [(1R)-1-(tert-butoxycarbonylamino)ethyl]-[(2S)-3-[[(1S)-2-tert-butoxy-1-methyl-2-oxo-ethyl]amino]-3-oxo-2-[(4-phenylphenyl)methyl]propyl]phosphinic acid (Compound Db) TBTU (0.862 g, 3 eq.) followed by DIPEA (0.578 g, 5 eq.) are successively added to compound (Cb) (0.4 g, 0.895 mmol) followed by AlaOtBu·HCl salt (0.195 g, 1.2 eq.) in DMF (2 mL, 5 vol.) at 0 °C. The reaction mixture is stirred for 1 h, after which AcOEt (5 mL, 10 vol.) and 1 N HCl (2.55 mL, 2.85 eq.) are added and the mixture is allowed to warm to room temperature. The aqueous phase is extracted with iBuOAc (2 x 2 mL, 2 x 5 vol.). The organic phases are combined and washed with 10% NaHCO3 (3x2 mL, 3x5 vol), 1N HCl (2 mL, 5 vol) and 10% NaCl (2 mL, 5 vol), then concentrated and dried under reduced pressure to obtain compound (Db) in the form of a solid (0.356 g, 0.62 mmol, 69%). NMR (DMSO D6 + TFA): 1 H (400 MHz) d 1.13 (m, C(2)CH3, 3H); 1.23 (d, 3H, C(8)H3); 1.36 (br s,18H, 2 x tBu); 1.59 and 1.91 (2 m, 1H+1H, C(4)H2); 2.8 (m, 1H, C(5)H); 3.0 (m, 2H, C(5)CH2); 3.65 (m, 1H, C(2)H); 4.11 (m, 1H, C(8)H); 6.80 (d, 1H, N(1)H); 7.31 and 7.34 (m, 3H, aromatic); 7.45 (m, 2H, aromatic); 7.54 (d, 2H, aromatic); 7.62 (d, 2H, aromatic) and 8.30 (d, 1H, N(7)H). 31 P 46.5 (only 2S diastereoisomer detected).

[0229] ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((((R)-1-aminoethyl)(hydroxy)phosphoryl)methyl)propanoyl)-L-alaninic acid (Compound E (PL254)) 88% HCOH (1 mL, 12 volumes) is added to compound (Db) (85 mg, 0.148 mmol). The solution is heated to 50° C. with stirring for 2 hours, then concentrated to give an oil, which is triturated in MTBE (2 mL, 24 volumes). The product is filtered and then dried under reduced pressure to give compound (E) (58 mg, 94%). NMR (DMSO D6 + TFA): 1 H (400 MHz) d 1.22 (dd, 3H, C(2)CH3); 1.30 (dd, 3H, C(8)H3); 1.64 and 2.18 (2 m, 1H+1H, C(4)H2); 2.73 (m, 1H, C(5)H); 3.06 (m, 2H, C(5)CH2); 3.25 (m, 1H, C(2)H); 4.23 (m, 1H, C(8)H); 7.30-7.70 (m, 9H, aromatic); 8.08 (br s, 3H, N(1)H3 + ) and 8.52 (d, 1H, N(9)H). 31 P 41.2 (only 2S 1 diastereoisomer detected). HPLC purity (254 nm, Kromasil C18, 250 mm × 4.6 mm, 5 μm), H2O (0.01% TFA)-CH3CN (0.01% TFA) 90 / 10 for 2 min, then 10 / 90 over 14 min, 10 / 90 for 4 min: 97.70%, t R : 10.29 minutes.

[0230] Synthesis of compound (E) by sequential condensation during the various steps For example, starting from the "native" compound (B) (2S / 2R) 57 / 43, derived from step (2b.2.1) as described above, it has been shown that the desired diastereoisomer can be enriched during various steps.

[0231] Compound (B) (2S / 2R: 81 / 19) The "neat" compound (B) (2S / 2R) 57 / 43 is suspended in iBuOAc (50 mL, 5 vol) and water (50 mL, 5 vol) and stirred for 2 h. The suspension is filtered to give a wet cake (12 g). The solid is treated with acetone (50 mL, 5 vol), suspended on the filter for a few minutes, then filtered and dried under vacuum to give the incorrect diastereoisomer (1R, 2R) (1.26 g, yield: 24%, 2R / 2S ratio: 31 P 79 / 21). The filtrate is concentrated to dryness to give the correct diastereoisomer (B) in solid form (3.18 g, yield: 60%, (2S / 2R): 81 / 19). NMR D6 DMSO+TFA, 31 P 39.37 (0.81 P, diastereoisomer 2S) and 39.60 (0.19 P, diastereoisomer 2R).

[0232] Compound (Cb) (2S / 2R: 93 / 7) 1N NaOH (4.43 mL, 1 eq.) is added to an ice-bath cooled suspension of compound (B) obtained above (2 g, 4.43 mmol, 2S / 2R 81 / 19) in EtOH (30 mL, 15 vol.) and H2O (15 mL, 7.5 vol.). The mixture is stirred at room temperature until complete solubilization. 10% Pd / C (0.20 g, 10% by weight with respect to compound (B), 50% wet) is added. The reaction mixture is purged with N2, then with H2 (3 cycles of vacuum / N2, then with 3 cycles of vacuum / H2) and stirred under 1 bar H2 at 20-30 °C for 18 h. The pH is recorded for reference (pH around 7-8). The reaction mixture is filtered through 0.45 μm. 1N NaOH (4.4 mL, 1 eq.), Boc2O (1.05 g, 1 eq.) followed by 1N NaOH (4.4 mL, 1 eq.) are added successively. The mixture is stirred at room temperature for 2 h and then partially concentrated to remove EtOH. The aqueous phase is washed with MTBE (10 mL, 5 vol.) followed by 1N HCl (1.75 mL, 4 eq.). The organic phase is separated and concentrated to dryness to give a solid. This is suspended in MTBE (10 mL, 5 vol.) and H2O (0.24 mL, 3 vol.) for 1 h. The suspension is filtered and then dried under vacuum to give compound (Cb) (1.05 g, yield: 53%, 2S / 2R=93 / 7). NMR D6 DMSO+TFA, 31P 46.20 (diastereoisomer 2R, 0.07P) and 46.37 (diastereoisomer 2S, 0.93P).

[0233] Compound (Db)(2S / 2R 92 / 8) TBTU (1.96 g, 3 eq.) followed by DIPEA (1.316 g, 5 eq.) are successively added to the previously obtained compound (Cb) (0.91 g, 2.04 mmol) and then to AlaOtBu·HCl salt (0.44 g, 1.2 eq.) in DMF (5 mL, 5 vol.) at 0 °C. The reaction mixture is stirred for 1 h, then EtOAc (5 mL, 5 vol.) and 1N HCl (6 mL, 3 eq.) are added and the mixture is allowed to warm to room temperature. The aqueous phase is extracted with EtOAc (4 mL, 2 vol.). The organic phases are combined and then washed with 10% NaHCO3 (3 x 4 mL, 3 x 2 vol.), 1N HCl (4 mL, 2 vol.) and 10% NaCl (4 mL, 2 vol.). The solution is concentrated and dried under vacuum to give compound (Cb) in solid form (1.058 g, 1.84 mmol, yield: 90%, 2S / 2R=92 / 8). NMR D6 DMSO+TFA, 31 P 46.56 (0.92 P, diastereoisomer 2S) and 46.88 (0.08 P, diastereoisomer 2R).

[0234] Compound (E) (2S / 2R 93 / 7) 88% HCOH (5 mL, 12 volumes) is added to the previously obtained compound (Db) (1.06, 1.84 mmol). The solution is heated to 50° C. with stirring for 2 hours, then concentrated to give an oil, which is triturated in MTBE (8 mL, 8 volumes). The mixture is concentrated and dried under vacuum to give compound (E) (0.62 g, yield: 80%, (2S / 2R): 93 / 7). NMR D6 DMSO+TFA, 31 P 41.33 (diastereoisomer 2S, 0.93P) and 41.97 (diastereoisomer 2R, 0.07P)

[0235] Compound (E) (0.5 g) is suspended in CHCl (4 mL, 8 vol) and stirred for 1 h. The thin suspension is filtered and dried under vacuum to give compound (E) (0.45 mg, yield: 72%, (2S / 2R): 94 / 6). HPLC (254 nm, Kromasil C18, 250 mm × 4.6 mm, 5 μm), H2O (0.01% TFA)-CH3CN (0.01% TFA) 90 / 10 for 2 min, then 10 / 90 over 14 min, then 10 / 90 for 4 min) purity 98.2%, t R : 10.31 minutes.

[0236] ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alaninic acid (Compound F) 900 g (1.8 mol) of compound (E) is solubilized in 2.7 L of DMF and the mixture is stirred at room temperature (15-20° C.) until a clear solution is obtained. It is then cooled to 5-10° C. and 492.4 g (1.8 mol) of acyloxyalkyl carbamate is added in small portions and the mixture is stirred at 5-10° C. until a clear solution is obtained. 382.3 g (3.79 mol) of triethylamine is added slowly while maintaining the temperature below 15° C. After the addition, the mixture is stirred at 15-20° C. for 4 hours while monitoring the reaction by HPLC. 4.5 L of ethyl acetate is added, the mixture is cooled to 5-10° C. and 1N aqueous HCl is added slowly to adjust the pH to 2-3 while maintaining the temperature below 25° C. (Note: Approximately 2.2 L of 1N aqueous HCl was used). 3.2 L of water is added and the mixture is stirred at room temperature for 10 minutes. The organic phase of the product is separated and the aqueous phase is extracted with ethyl acetate (1×4.5 L). The organic phases are combined and washed with water (4×3.6 L) and brine (1×3.6 L). The organic phases are concentrated under reduced pressure at 40-45° C. to remove approximately 90% of the ethyl acetate. 2.7 L of ethyl acetate are added to the residue and the mixture is stirred at 45-50° C. for 30 minutes. The mixture is concentrated under vacuum at 40-45° C. to remove approximately 80% of the ethyl acetate. 2.7 liters of diisopropyl ether are added to the residue and the mixture is subsequently concentrated to drive off the remaining ethyl acetate. Then 9 L of diisopropyl ether are added and the mixture is stirred at room temperature (approximately 20° C.) for 1 hour. The solid product is isolated and dried overnight under air flow at 30-35° C. to obtain 925 g of compound (F) in the form of a pale yellow solid (HPLC purity 98.1%).

[0237] Disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alaninic acid (Compound (I)) 136.27 g (0.24 mol) of compound (F) is solubilized in 683 mL of THF and the mixture is stirred at room temperature (15-25° C.) until a clear solution is obtained. 137 mL of water is added to the solution, which is then filtered under N2 at room temperature (15-25° C.), after which sodium bicarbonate (39.71 g) is added at room temperature (15-25° C.). The mixture is stirred at room temperature (15-25° C.) for at least 30 minutes until gaseous emissions disappear. The solution is concentrated under reduced pressure at 20-25° C. The residue is diluted with 1.0 L of THF and then concentrated under reduced pressure at 20-25° C. several times to remove water. 1.4 L of diisopropyl ether is added to the residue. The suspension is stirred with mechanical stirring at 15-25° C. for 1 hour, after which the solid obtained is filtered, washed and dried to obtain 133.9 g of compound (I) in the form of an off-white solid (yield: 91%, HPLC purity: 98.6%).

Claims

1. The following formula (E) 【Chemistry 1】 1. A method for industrially producing ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((((R)-1-aminoethyl)(hydroxy)phosphoryl)methyl)propanoyl)-L-alaninic acid, comprising: (1) The following formula (A) 【Chemistry 2】 The compound (1a) (S)-1-phenylethylamine is reacted with hypophosphorous acid H in a polar protic solvent in the presence of a molar equivalent of hydrochloric acid relative to the (S)-1-phenylethylamine. 3 PO 2 and acetaldehyde, and then (1b) treating the resulting salt from step (1a) with propylene oxide, followed by (1c) crystallizing using a polar and protic solvent and recovering the compound of formula (A) by filtration. and (2) The following formula (B) 【Chemistry 3】 The compound (2a) reacting the compound of formula (A) derived from step (1) with the benzyl ester of (2-(4-biphenyl)methyl)acrylate in the presence of a source of trimethylsilyl group, followed by (2b) A compound of formula (B), (2b.1) crystallization using a mixture of a non-polar aprotic solvent and water, followed by filtration; or (2b.2) triturating in acetone, filtering and evaporating the filtrate The process of recovering by and (3) The following formula (C) 【Chemistry 4】 where P' is a protecting group for the amine functionality. The compound (3a) hydrogenolysis of the compound of formula (B) under a hydrogen atmosphere in the presence of 10% by weight of Pd / C relative to the weight of the compound of formula (B), followed by (3b) protecting the amine resulting from step (3a) with a protecting group P' to recover a compound of formula (C). and (4) A compound of formula (E), (4a) The compound of formula (C) is peptide-coupled with the tert-butyl ester of (L)-alanine to obtain the compound of formula (D) 【Chemistry 5】 recovering the compound of formula (I); (4b) Deprotecting the protecting group P′ at the N-terminal position and the tert-butyl group at the C-terminal position to recover the compound of formula (E). By this, the manufacturing process and A method comprising:

2. 2. The process according to claim 1, characterized in that in steps (1a) and (1c), the polar and protic solvents are selected from among alcohols.

3. 3. The process according to claim 1 or 2, characterized in that in step (2b), the non-polar aprotic solvent is MTBE.

4. Step (3a) comprises the following sequential steps: (3a.1) preparing a suspension of a compound of formula (B) in a protic solvent or a mixture of protic solvents; (3a.2) adding a base to the suspension prepared in step (3a.1); (3a.3) To the suspension resulting from step (3a.2), 10% by weight of Pd / C relative to the weight of the compound of formula (B) is added, and the resulting reaction mixture is subjected to H 2 purging with (3a.4) filtering and concentrating the reaction mixture 4. The method according to claim 1 , characterized in that it comprises:

5. 5. The method according to claim 1, wherein the protection step (3b) is carried out in a basic medium.

6. 6. The method of claim 5, wherein P' is selected from the group consisting of CBz and Boc groups.

7. Step (4a) comprises the following sequential steps: (4a.1) adding tert-butyl ester of (L)-alanine and a peptide coupling agent to a solution containing a compound of formula (C) dissolved in DMF or a THF / DMF mixture; (4a.2) adding a base to the reaction mixture resulting from step (4a.1); (4a.3) recovering the compound of formula (D) as defined in claim 1.

7. The method according to claim 1, comprising:

8. The following formula (I) 【Chemistry 6】 1. A method for industrially producing the disodium salt of ((2S)-3-([1,1'-biphenyl]-4-yl)-2-((hydroxy((1R)-1-(((1-(isobutyryloxy)ethoxy)carbonyl)amino)ethyl)phosphoryl)methyl)propanoyl)-L-alanine, comprising: Steps (1) to (4) as defined in any one of claims 1 to 7, and immediately following step (4), the following sequential steps (5) and (6): (5) The following formula (F) 【Chemistry 7】 A compound of formula (E) is reacted with a compound of formula (E) in the presence of a base to form a compound of formula (E) 【Chemistry 8】 with a compound of (6) recovering the compound of formula (I) by precipitation in a non-polar aprotic solvent in the presence of a sodium salt of a weak base. A method comprising:

9. Step (5) comprises the following sequential steps: (5a) The compound of formula (E) is reacted with a compound of the formula 【Chemistry 9】 with a compound of (5b) crystallizing using an aprotic non-polar solvent and recovering the compound of formula (F) by filtration.

9. The method of claim 8, comprising:

10. The following formula (B) 【Chemistry 10】 Compound.

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