Improved synthesis of psilocybin derivatives

Abstract

The present invention relates to improved syntheses of psilocybin and alkyl derivatives of psilocybin, such as ethosybin (4-phosphoryloxy-N,N-diethyltryptamine, also known as phosphoryloxy-DET, PO-DET, or CEY-39), as well as to intermediates useful in the synthesis of these compounds.

Description

[Background technology]

[0001] Background of the Invention The present invention relates to an improved synthesis of psilocybin and alkyl derivatives of psilocybin (IUPAC name: 4-phosphoryloxy-N,N-dimethyltryptamine 3-[2-(dimethylamino)ethyl]-1H-indol-4yl-dihydrogen phosphate), such as ethosybin (IUPAC name: mono-[3-(2-diethylamino-ethyl)-1H-indol-4yl]phosphate ester), as well as intermediates useful in the synthesis of these compounds.

[0002] Psilocybin and its derivatives, such as its dephosphorylated active metabolite psilocin, have recently attracted renewed interest due to their potential utility in the treatment of various psychiatric disorders (Dinis-Olivera RJ Drug Metab. Rev. 2017, 49(1), 84-91). For example, the compound has been demonstrated to be useful in the treatment of depression.

[0003] Psilocybin was first isolated from the mushroom P. Mexicana in the laboratory of Albert Hoffmann in 1958 (Hofmann, A., Frey, A., Ott, H., Petrzilika, F., Troxler, F.; Experientia 14, 1958, 397-399). Shirota et al. more recently published a concise large-scale synthesis of psilocin and psilocybin without chromatographic purification steps (Shirota O., Hakamata W. and Goda Y.; J. Nat. Prod. 2003, 66(6), 885-887).

[0004] The synthesis of alkyl derivatives of psilocybin, such as ethosybin (4-phosphoryloxy-N,N-diethyltryptamine), also known as phosphoryloxy-DET, PO-DET, or CEY-39, is disclosed in U.S. Pat. No. 3,075,992.

[0005] Macor, Post and Ryan disclose a simple synthesis of 5-amino-3-(2-dimethylaminoethyl)indole (https: / / doi.org / 10.1080 / 00397919308020402).

[0006] However, when these compounds are prepared on a large scale using the synthetic procedures described in the prior art, low overall yields are obtained. Furthermore, scale-up is significantly hindered by the required chromatographic purification steps, which are more difficult to carry out at that scale. Thus, there is a need for alternative synthetic procedures that allow for higher overall yields, especially when synthesizing on a multigram or kilogram scale, especially in compliance with Good Manufacturing Practice requirements.

[0007] Document WO 2022 / 016289 discloses a method for preparing psilocybin starting from psilocin and (tert-BuO)2POCl. The process disclosed in WO 2022 / 016289 requires the use of CCl4 in certain embodiments, which makes the scale-up of the reaction and its industrial application less advantageous.

[0008] Troxler F. et al. (Helvetica Chimica Acta, vol. 42, no. 6, pages 207302193) disclose the phosphorylation of hydroxyindole derivatives using dibenzylphosphoryl chloride. Summary of the Invention

[0009] It is therefore an object of the present invention to provide a novel process for the preparation of alkyl derivatives of psilocybin, such as ethosybin, with improved overall yields, particularly when the synthesis is carried out on a multigram or kilogram scale while avoiding chromatographic purification.

[0010] The inventors have surprisingly found that said object can be achieved by the synthetic method outlined in the present patent application and claimed in the appended claims.

[0011] The present invention therefore provides a compound of formula (I):

[0012] [ka]

[0013] wherein each R independently represents C 1-6 alkyl (preferably methyl or ethyl), wherein the method comprises reacting a compound of formula (Id):

[0014] [ka]

[0015] with (EtO)2POCl (DECP). Preferably, the product of the reaction of the compound of formula (Id) with DECP is further reacted with trimethylsilyl bromide (TMSBr) to provide the compound of formula (I).

[0016] In a preferred process according to the invention, R is methyl.

[0017] In one embodiment of the invention, the w / w ratio of the compound of formula (Id) and (DECP) is between 0.8 and 1.2, preferably between 1.0 and 1.2, more preferably between 1.10 and 1.15, even more preferably about 1.12, even more preferably 1.12.

[0018] In another embodiment of the present invention, the DECP is added dropwise over a period of between 10 and 20 minutes.

[0019] In a further embodiment of the invention, the reaction of the compound of formula (Id) with DECP is carried out in acetonitrile.

[0020] In a further embodiment of the invention, the reaction of the compound of formula (Id) with DECP is carried out at a temperature between 50°C and 70°C, preferably between 55°C and 65°C, more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, even more preferably at a temperature of 60°C.

[0021] In a further embodiment of the invention, the reaction of the compound of formula (Id) with DECP is carried out in the presence of a base, preferably wherein the base is N-ethyl-diisopropylamine.

[0022] In a further embodiment of the invention, the reaction of the compound of formula (Id) with DECP is carried out for a period of at least 150 minutes, until at least 99% of the compound of formula (Id) has reacted.

[0023] In a further embodiment of the present invention, the reaction of the compound of formula (Id) with DECP is carried out by changing the solvent to toluene and adding an aqueous solution of NaOH thereto, followed by phase separation. Preferably, NaOH is added at a concentration of 0.5 M to 1.0 M, preferably at a concentration of about 0.75 M, more preferably at a concentration of 0.75 M.

[0024] In a further embodiment of the present invention, upon completion of the reaction of the compound of formula (Id) with DECP, the solvent is changed to cyclopentyl methyl ether (CPME), and HCl in CPME is added to the reaction mixture, which leads to the precipitation of the crude product. In a preferred embodiment, the HCl in CPME is about a 3 M solution, and / or wherein said solution is added dropwise over a period of between 25 and 35 minutes, and / or wherein said solution is added at a temperature between 15 and 20°C, preferably between 17 and 23°C, more preferably at a temperature of about 20°C, and even more preferably at a temperature of 20°C.

[0025] In another aspect of the invention, the reaction of a compound of formula (Id) with DECP gives a compound of formula (Ie):

[0026] [ka]

[0027] yielding a crude product of

[0028] In a preferred embodiment of the invention, the crude product precipitated from CPME upon addition of HCl comprises a compound of formula (Ie), wherein each R is as defined for formula (I).

[0029] In embodiments of the present invention in which a compound of formula (Id) is reacted with DECP, the DECP is a compound of formula (R'O)2POCl, where each R' is independently 1-6 alkyl, -CH2-aryl or -CH2-heteroaryl, preferably each R' is independently selected from C 1-6 alkyl and -CH2-aryl, more preferably each R' is independently selected from C 1-6 It should be understood that those skilled in the art will recognize that in the first step of the method of the present invention, the compound of formula (Id) can be replaced with a compound of formula (R'O)2POCl (wherein each R' is independently C 1-6 alkyl, -CH2-aryl or -CH2-heteroaryl, preferably C 1-6 The compound may be reacted with a compound of formula (C) selected from -alkyl and -CH-aryl. 1-6 The alkyl groups are ethyl and tert-butyl. A particularly suitable -CH2-aryl is benzyl.

[0030] In a further embodiment of the present invention, the product of the reaction of the compound of formula (Id) with DECP is further reacted with trimethylsilyl bromide (TMSBr) to give a compound of formula (I), whereby preferably the w / w ratio of TMSBr to the compound of formula (Id) is between 1.5 and 2.5, preferably between 1.8 and 2.4, more preferably between 2.0 and 2.3, even more preferably about 2.1, and even more preferably 2.07.

[0031] In a further embodiment of the invention, the product of the reaction of the compound of formula (Id) with diethyl chlorophosphate (DECP) is reacted with TMSBr in acetonitrile, whereby preferably TMSBr is added at a temperature of 30°C to 50°C, preferably between 35°C and 45°C, more preferably between 37°C and 43°C, even more preferably at a temperature of about 40°C, even more preferably at a temperature of 40°C.

[0032] In a further embodiment of the invention, the product of the reaction of the compound of formula (Id) with DECP is reacted with TMSBr at a temperature between 50°C and 70°C, preferably between 55°C and 65°C, more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, and even more preferably at a temperature of 60°C.

[0033] In a further preferred embodiment of the present invention, wherein the reaction with TMSBr is carried out for at least 150 minutes until the product of the reaction of the compound of formula (Id) with DECP is at least 99% consumed.

[0034] In a further preferred embodiment of the present invention, the solvent is changed to methanol upon reaction with TMSBr, whereby the methanol is preferably removed by distillation and the remaining solid residue is dissolved in methanol, and the solution thus obtained is treated with activated carbon and filtered.

[0035] In a further embodiment of the present invention, wherein the obtained product of the reaction with TMSBr is subjected to a solvent change to water, wherein the pH of the solution is set to a value ranging between pH=3.8 and pH=4.2, preferably through the addition of 1 M NaOH.

[0036] In a preferred embodiment of the present invention, the w / w ratio of 1 M NaOH solution to the original amount of compound of formula (Id) added is about 4.0, preferably 4.0.

[0037] In a further embodiment of the invention, wherein the final product of formula (I) precipitates from the aqueous solution at a pH between 3.8 and 4.2 and / or at a temperature below 20°C, preferably at a temperature of about 15°C, more preferably at a temperature of 15°C.

[0038] In a further embodiment of the present invention, the final product of formula (I) is treated with water / acetone under reflux.

[0039] In a further embodiment of the invention, the method further comprises reacting a compound of formula (Ic):

[0040] [ka]

[0041] to give a compound of formula (Id), whereby preferably, in the step of reducing a compound of formula (Ic) to give a compound of formula (Id), LAH is used as the reducing agent, whereby in a preferred embodiment, the step of reducing a compound of formula (Ic) to give a compound of formula (Id) is carried out in toluene, in dioxane or in CPME, preferably in toluene, more preferably said step is carried out under reflux. In formula (Ic), each R is as defined for formula (I).

[0042] In a further preferred embodiment of the present invention, NaBH4 is used as the reducing agent in the step of reducing the compound of formula (Ic) to give the compound of formula (Id).

[0043] In a further preferred embodiment of the present invention, the method further comprises reacting a compound of formula (Ia):

[0044] [ka]

[0045] with oxalyl chloride (COCl) followed by reaction of the resulting product with a dialkylamine (RNH), for example, diethylamine, where R is as defined for formula (I).

[0046] In a further preferred embodiment of the invention, the reaction of a compound of formula (Ia) with (COCl)2 is carried out in CPME at a temperature between 0 and 10°C.

[0047] In a further preferred embodiment of the present invention, said reaction of a compound of formula (Ia) with (COCl)2 gives a compound of formula (Ib):

[0048] [ka]

[0049] wherein the compound of formula (Ib) is reacted with R2NH to provide a compound of formula (Ic), wherein each R is as defined for formula (I).

[0050] The present invention will be more fully understood by reference to the following examples, which, however, should not be construed as limiting the scope of the invention.

[0051] The experimental methods described in the Examples section below are further illustrated by the accompanying diagrams, which show the following equipment setup: [Brief explanation of the drawings]

[0052] [Figure 1] FIG. 1 illustrates the apparatus set up for step 1 of the example, which illustrates the acid chloride formation step in the process for the preparation of acetoxyindole glyoxylic acid diethylamide and the corresponding mass flow rate and mass balance chart, and the amide formation step in the process for the preparation of acetoxyindole glyoxylic acid diethylamide and the corresponding mass flow rate and mass balance chart. [Figure 2] FIG. 2 illustrates the apparatus set up for step 2 of the example, which illustrates the process for the preparation of 4-HO-DET and the corresponding mass flow and mass balance charts. [Figure 3] FIG. 3 illustrates the equipment set up for step 3 of the example, which illustrates the process for the preparation of crude ethosybin and the corresponding mass flow and mass balance charts. [Figure 4] FIG. 4 illustrates the equipment set up for step 4 of the example, which illustrates the preparation of the final ethosibin product and the corresponding mass flow and mass balance charts. [Figure 5] FIG. 5 shows analytical data for acetoxyindole glyoxylic acid diethylamide (product of Step 1 in the Examples), namely, HPLC data (part 1), LC-MS data including UV-VIS spectrum (parts 2 and 3), H and C NMR spectra (parts 4 and 5, respectively), and DSC measurement (part 6). [Figure 6] FIG. 6 shows analytical data for ethosin (4-OH-DET, product of Step 2 in the Examples), namely, HPLC data (part 1), LC-MS data including UV-VIS spectra (parts 2 and 3), H and C NMR spectra (parts 4 and 5, respectively), and DSC measurements. [Figure 7] FIG. 7 shows analytical data for crude ethosivine (product of Step 3 in the Example), namely, HPLC data (part 1), LC-MS data including UV-VIS spectra (parts 2 and 3), and DSC measurements (part 4). [Figure 8] FIG. 8 shows analytical data for etosivine (API / drug substance / final product), the product of Step 4 in the Example, including HPLC data (part 1), LC-MS data including UV-VIS spectra (parts 2 and 3), H and C NMR spectra (parts 4 and 5, respectively), and DSC measurements. [Figure 9]FIG. 9 shows an exemplary reaction scheme leading to the preparation of psilocybin (a compound of formula (I) where both R are methyl). [Figure 10] FIG. 10 shows the HPLC data (part 1) and 1H-NMR spectrum in d6-DMSO (part 2) for acetoxyindole glyoxylic acid dimethylamide. [Figure 11] FIG. 11 shows the HPLC data (part 1) and 1H-NMR spectrum in d6-DMSO (part 2) for 4-hydroxy-dimethyltryptamine. [Figure 12] FIG. 12 shows HPLC data (part 1) and the H-NMR spectrum in DO (part 2) for psilocybin. DETAILED DESCRIPTION OF THE INVENTION

[0053] Detailed Description of the Invention The invention is described in the following embodiments, and it should be understood that all possible combinations of the disclosed steps and / or features are contemplated unless otherwise indicated.

[0054] In one embodiment, the present invention provides a compound of formula (I):

[0055] [ka]

[0056] wherein each R independently represents C 1-6 Preferably, each R is independently methyl or ethyl. More preferably, each occurrence of R is ethyl.

[0057] The method of the present invention comprises reacting a compound of formula (Id):

[0058] [ka]

[0059] with (EtO)2POCl (which can also be called diethyl chlorophosphite or DECP).

[0060] Preferably, in the method of the present invention, the w / w ratio of the compound of formula (Id) and (DECP) is between 0.8 and 1.2. More preferably, the w / w ratio of the compound of formula (Id) and (DECP) is between 1.0 and 1.2. Even more preferably, the w / w ratio of the compound of formula (Id) and (DECP) is between 1.10 and 1.15. Even more preferably, the w / w ratio of the compound of formula (Id) and (DECP) is about 1.12. Most preferably, the w / w ratio of the compound of formula (Id) and (DECP) is 1.12.

[0061] As understood herein, whenever referring to a number representing a ratio or concentration, the term "about" is meant to be understood preferably as ±2%, more preferably as ±1%. Furthermore, as understood herein, whenever referring to a temperature, the term "about" is meant to be understood preferably as ±1°C, more preferably as ±0.5°C.

[0062] Those skilled in the art who carry out the process of reacting a compound of formula (Id) with DECP will be able to arrange for the appropriate mixing of both components. According to the present inventors, it may be preferable to carry out the reaction in a manner that avoids an excessive excess of DECP relative to (Id) at any given time. This can be achieved by adding (or providing) DECP in (Id). That is, it is preferred to add DECP to (Id). It is further preferred to add DECP dropwise to (Id), preferably over a period of at least 10 minutes, more preferably between 10 and 30 minutes, and even more preferably between 10 and 20 minutes.

[0063] According to the present inventors, the reaction of DECP with the compound of formula (Id) should preferably be carried out in a polar and aprotic solvent, such as acetonitrile or DMF. A particularly preferred solvent for this reaction is acetonitrile. That is, in a further embodiment of the present invention, the reaction of the compound of formula (Id) with DECP is carried out in acetonitrile.

[0064] The use of solvents including acetonitrile or DMF, which are characterized by relatively high boiling points under normal conditions, allows for flexible selection of the reaction temperature required by the reactants. According to the present inventors, the reaction of the compound of formula (Id) with DECP is preferably carried out at a temperature between 50°C and 70°C, more preferably between 55°C and 65°C, even more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, and even more preferably at a temperature of 60°C.

[0065] The reaction of the compound of formula (Id) with DECP is carried out in the presence of a base. The present inventors have determined that the preferred base is N-ethyl-diisopropylamine. However, this is not intended to be limiting, and those skilled in the art will consider using other bases to determine their performance in the process of the present invention.

[0066] Preferably, according to the present invention, the reaction of the compound of formula (Id) with DECP is carried out until a specific desired fraction of the compound of formula (Id) has reacted. This should be understood to be equivalent to a specific fraction of the compound consumed, regardless of the reaction undergone by the compound of formula (Id). Preferably, the reaction should be carried out until at least 90%, at least 95%, or 99% of the compound of formula (Id) has reacted. More preferably, the reaction should be carried out until at least 99% of the compound of formula (Id) has reacted. Preferably, the progress of the reaction is monitored by using LC-MS or GC-MS analysis on a sample from the reaction mixture. Thus, the inventors have determined that the reaction between DECP and the compound of formula (Id) should preferably be carried out for a period of at least 150 minutes, until at least 99% of the compound of formula (Id) has reacted.

[0067] Then, in the next step of the reaction of the compound of formula (Id) with DECP, the solvent is changed to toluene, and an aqueous NaOH solution is added thereto. As will be apparent to those skilled in the art, phase separation is expected to occur at this point. Those skilled in the art tasked with preparing a suitable NaOH solution for this purpose will preferably not exceed a NaOH concentration of 2.0 M. Preferably, in the aqueous phase being added, NaOH is present at a concentration of 0.5 M to 1.0 M, preferably at a concentration of about 0.75 M, more preferably at a concentration of 0.75 M. This step of workup of the reaction mixture may also be referred to by those skilled in the art as basic aqueous workup. The aqueous phase is separated from the toluene phase. During workup, the aqueous phase thus obtained is preferably extracted twice with toluene to combine the toluene fraction (which, according to the inventors, contains the product of the reaction of the compound of formula (Id) with DECP). The combined toluene phases are then washed with diluted aqueous NaOH (e.g., 0.1 M NaOH solution, but other concentrations will be considered equally suitable by those skilled in the art), followed by two washes with deionized water. As known to those skilled in the art, the aqueous workup may be completed by stirring the toluene phase thus obtained with activated carbon, drying it over sodium sulfate, and filtering the fraction thus obtained over Celite. The toluene fraction thus worked up is then ready for use in the next step.

[0068] Upon completion of the reaction of the compound of formula (Id) with DECP and carrying out the above-described toluene / aqueous NaOH workup, the solvent is changed to cyclopentyl methyl ether (CPME). Subsequently, HCl in CPME is added to the reaction mixture, leading to precipitation of the crude product. Preferably, the solvent exchange is carried out through evaporation of the previous solvent with gradual addition of the target solvent, herein CPME. The preferred concentration of HCl in CPME does not exceed 5 M, more preferably between 2 M and 4 M. In a preferred embodiment, the HCl in CPME is an approximately 3 M solution. To avoid unwanted side reactions, as will be apparent to those skilled in the art, the solution of HCl in CPME is added dropwise over a period of time. Preferably, the solution of HCl in CPME is added dropwise over a time span of at least 10 minutes, preferably over a time span of at least 20 minutes. More preferably, the solution of HCl in CPME is added dropwise over a time span of between 20 and 40 minutes, and even more preferably over a time span of between 25 and 35 minutes. As will be apparent to those skilled in the art, it is preferable to control the temperature during the addition of HCl in CPME to the reaction mixture. Thus, in a preferred embodiment of the present invention, the solution is added at a temperature between 15° C. and 25° C., preferably between 17° C. and 23° C., more preferably at a temperature of about 20° C., and even more preferably at a temperature of 20° C.

[0069] According to the present inventors, upon addition of HCl in CPME, a precipitate of the crude product of the reaction of the compound of formula (Id) with DECP is formed. As will be apparent to those skilled in the art, the suspension thus obtained is then preferably filtered under reduced pressure, and the filter cake thus obtained is washed with CPME. The filter cake (which may also be referred to as the crude product of the reaction of the compound of formula (Id) with DECP) is then dried under reduced pressure.

[0070] Without being bound by theory, it is believed that the reaction of a compound of formula (Id) with DECP produces a compound of formula (Ie):

[0071] [ka]

[0072] It is noted that this gives a crude product of

[0073] In formula (Ie), each R is as defined for formula (I). That is, according to the present inventors, the crude product precipitated from CPME upon addition of HCl described above comprises a compound of formula (Ie). That is, in a preferred embodiment of the present invention, reaction of a compound of formula (Id) with DECP results in a crude product of formula (Ie). In a further preferred embodiment of the present invention, the crude product precipitated from CPME upon addition of HCl comprises a compound of formula (Ie).

[0074] According to the inventors, the formula (If):

[0075] [ka]

[0076] A compound of formula (If) may be present in the reaction mixture. In formula (If), each R is as defined for formula (I). Without being bound by theory, the inventors hypothesize that this product is formed as a by-product of the reaction of DECP with the compound of formula (Id) due to the presence of ethyl chloride, which, according to the inventors, forms upon reaction of the compound of formula (Id) with DECP. Further possible reasons for the occurrence of this side reaction include the presence of ethyl chloride impurities during the preparation of the DECP used. According to the inventors, the compound of formula (If) may also be formed in the alkylation reaction of the amine group in (Id) or (Ie) (shown as a protonated form in the above formula) with DECP. That is, according to the inventors, the compound of formula (If) may be present in the crude product of the compound of formula (Id) with DECP. The inventors have demonstrated that the compound of formula (If) may be depleted in the reaction mixture or may be substantially removed from the reaction mixture through subsequent aqueous workup.

[0077] The present inventors have detected a compound of formula (Id) and a compound of formula (Ig) upon reaction of DECP:

[0078] [ka]

[0079] In formula (Ig), each R is as defined for formula (I). The inventors hypothesize that the compound of formula (Ig) is formed in the process of basic aqueous work-up of the product. According to the inventors, when the compound of formula (Ig) is present in the reaction mixture, it can be extracted during basic aqueous work-up, and thus can be separated from the product. However, the inventors have noticed that the formation of the compound of formula (Ig) can have a significant impact on the yield of the process.

[0080] The inventors further hypothesize that the formation of the compound of formula (Ig) can be preferably suppressed (or reduced) by controlling the temperature, duration, and pH of the reaction. More preferably, the formation of the compound of formula (Ig) can be suppressed (or reduced) by controlling the temperature. Therefore, it is preferred that the addition of NaOH is carried out at a temperature of 0°C to 5°C. Preferably, the internal temperature of the reactor is taken into consideration here.

[0081] Preferably, within the scope of the present invention, the product of the reaction of the compound of formula (Id) with DECP as described above is further reacted with TMSBr to give the compound of formula (I), which reaction may also be referred to herein as the deprotection reaction.

[0082] Thus, the present invention provides a compound of formula (I):

[0083] [ka]

[0084] wherein each R independently represents C 1-6and preferably each R is independently methyl or ethyl, wherein the method comprises reacting a compound of formula (Id):

[0085] [ka]

[0086] with (EtO)2POCl(DECP), wherein the product of reaction of the compound of formula (Id) with DECP is further reacted with TMSBr to provide the compound of formula (I).

[0087] Preferably, the w / w ratio of TMSBr to the product of the reaction of DECP with the compound of formula (Id) is between 1.5 and 2.5. More preferably, the w / w ratio of TMSBr to the compound of formula (Id) is between 1.75 and 2.25. Even more preferably, the w / w ratio of TMSBr to the compound of formula (Id) is between 1.9 and 2.1. Even more preferably, the w / w ratio of TMSBr to the compound of formula (Id) is about 2.0. Even more preferably, the w / w ratio of TMSBr to the compound of formula (Id) is 2.0.

[0088] Preferably, the compound of formula (Id) is reacted with TMSBr in a polar and aprotic solvent. Therefore, acetonitrile is a suitable solvent for this reaction. That is, preferably, the product of the reaction of DECP with (Id) is reacted with TMSBr in acetonitrile. As will be understood by those skilled in the art, this step will involve dissolving the crude product obtained in the previous step, which may be the compound of formula (Ie) according to the present inventors, in acetonitrile. Therefore, preferably within the scope of the present invention, the crude product of the reaction of the compound of formula (Id) is charged into a suitable reactor together with a solvent, preferably acetonitrile, as known to those skilled in the art.

[0089] Preferably, TMSBr is added to the product of the reaction of compound (Id) with DECP, preferably within 5 to 10 minutes at a temperature between 30°C and 50°C to the product of the reaction of compound (Id) with DECP, dissolved as described above. More preferably, TMSBr is added to the product of the reaction of compound (Id) with DECP, dissolved as described above, at a temperature between 35°C and 45°C. Even more preferably, TMSBr is added to the product of the reaction of compound (Id) with DECP, dissolved as described above, at a temperature between 37°C and 43°C. Even more preferably, TMSBr is added to the product of the reaction of compound (Id) with DECP, dissolved as described above, at a temperature of about 40°C. Even more preferably, TMSBr is added to the product of the reaction of compound (Id) with DECP, dissolved as described above, at a temperature of 40°C.

[0090] Preferably, the product of the reaction of the compound of Formula (Id) with DECP is reacted with TMSBr at a temperature between 50°C and 70°C. More preferably, the product of the reaction of the compound of Formula (Id) with DECP is reacted with TMSBr at a temperature between 55°C and 65°C. Even more preferably, the product of the reaction of the compound of Formula (Id) with DECP is reacted with TMSBr at a temperature between 57°C and 63°C. Even more preferably, the product of the reaction of the compound of Formula (Id) with DECP is reacted with TMSBr at a temperature of about 60°C. Even more preferably, the product of the reaction of the compound of Formula (Id) with DECP is reacted with TMSBr at a temperature of 60°C.

[0091] The progress of the reaction of the product of the reaction of the compound of formula (Id) with DECP with TMSBr is monitored. Preferably, according to the present invention, the reaction of the product of the reaction of the compound of formula (Id) with DECP with TMSBr is carried out until a specific desired fraction of the product has reacted. This should be understood to be equivalent to a specific fraction of the compound being consumed, regardless of the reaction undergone by the compound. Preferably, the reaction should be carried out until at least 90%, at least 95%, or 99% of the product has reacted. More preferably, the reaction should be carried out until at least 99% of the product has reacted. Preferably, the progress of the reaction is monitored by using LC-MS or GC-MS analysis on a sample from the reaction mixture. Therefore, the inventors have established that preferably, the reaction between the product of the reaction of DECP and the compound of formula (Id), which may be a compound of formula (Ie), and TMSBr, should be carried out for a period of at least 150 minutes, until at least 99% of said product (which may be a compound of formula (Ie)) has reacted.

[0092] Further encompassed by the present invention are embodiments in which TMSBr is replaced with TMSI (which can be generated in situ using TMSCl and an iodide salt, such as KI, as will be apparent to those skilled in the art). Additionally, in TMSBr (or TMSI / TMSCl, as applicable), the methyl group(s) can be replaced with, for example, C 1-6 It will be apparent to one skilled in the art that other alkyl groups selected from alkyl can be substituted, however, most preferably, TMSBr is used in the present invention as described herein.

[0093] Preferably, upon completion of the reaction, the solvent is changed to methanol and the reaction mixture is stirred in methanol. Preferably, the stirring is carried out at a temperature between 55°C and 65°C. More preferably, the stirring is carried out at a temperature between 57°C and 63°C. Even more preferably, the stirring is carried out at a temperature of about 60°C. Even more preferably, the stirring is carried out at a temperature of 60°C. Preferably, the stirring is carried out for a period of at least 20 minutes, more preferably between 25 and 35 minutes, even more preferably for a period of about 30 minutes, even more preferably for a period of 30 minutes.

[0094] Preferably, methanol is distilled off from the reaction mixture at this point. It should be understood that preferably at least 50%, more preferably at least 70%, of the methanol is distilled off. As will be understood by those skilled in the art, certain by-products and side-products of the reaction may also be removed from the reaction mixture along with methanol. The residue thus obtained, including residual methanol, is supplemented with additional methanol and stirred. Preferably, the stirring is carried out at a temperature between 55°C and 65°C. More preferably, the stirring is carried out at a temperature between 57°C and 63°C. Even more preferably, the stirring is carried out at a temperature of about 60°C. Even more preferably, the stirring is carried out at a temperature of 60°C. Preferably, the stirring is carried out for a period of at least 20 minutes, more preferably between 25 and 35 minutes, even more preferably for a period of about 30 minutes, and even more preferably for a period of 40 minutes.

[0095] In one embodiment, the methanol can be completely removed, and the solid residue so obtained upon removal of the methanol is dissolved again in methanol, and the solution so obtained is preferably first incubated with activated carbon and subsequently filtered through Celite.

[0096] The solvent is then preferably changed to water. Thus, most of the methanol can be distilled off, and water is added. The pH of the solution thus obtained is set to a value ranging between pH=3.8 and pH=4.2. Preferably, the pH is set by adding an aqueous solution of NaOH, which is known to those skilled in the art. Preferably, according to the inventors, a 1M NaOH solution should be used. Therefore, the inventors used a w / w ratio of about 4 of 1M NaOH solution to the original amount of compound of formula (Id).

[0097] Preferably, once the pH is set to a value in the range between pH=3.8 and pH=4.2, the reaction mixture is concentrated under reduced pressure to reduce its volume.

[0098] Thus, and preferably, upon setting the pH to a value between 3.8 and 4.2, and preferably upon partially concentrating the solution as described above, the final product of formula (I) precipitates from the aqueous solution thus obtained. Preferably, upon setting the pH to a value in the range between pH=3.8 and pH=4.2, about four volumes, preferably four volumes (wherein said volume is understood relative to the volume of the obtained aqueous solution of the product of formula (I)), of isopropanol are added to the aqueous solution, and distillation / concentration at a jacket temperature of 70±5°C is carried out until about three volumes (as understood herein) of the solution remain in the reactor. To improve the yield of the process, the temperature of the process should be controlled. Preferably, the aqueous solution is kept at a temperature below 20°C. More preferably, the aqueous solution is kept at a temperature of about 15°C. Even more preferably, the aqueous solution is kept at a temperature of 15°C. It should be understood that the cooling to a jacket temperature of 15°C described herein is preferably carried out within 360 minutes.

[0099] Preferably, the precipitated product thus obtained is filtered under reduced pressure, and preferably washed with deionized water, deionized water / methanol mixture (preferably in a ratio of 1:1 v / v) and methanol.The product thus obtained is then dried under reduced pressure.Therefore, a crude preparation of the compound of formula (I) is obtained.

[0100] According to the present inventors, a compound of formula (Ih):

[0101] [ka]

[0102] wherein each R is as defined for formula (I) may be present in the reaction product. Without being bound by theory, the inventors hypothesize that this product may be formed due to the presence of ethyl bromide in the reaction mixture, which, according to the inventors, forms upon reaction of the product of the reaction of the compound of formula (Id) with DECP (which may be the compound of formula (Ie)) with TMSBr. The inventors have surprisingly found that the compound of formula (Ih) can be separated from the product of the deprotection reaction, i.e., from the compound of formula (I), in the process of crystallization of the compound of formula (I).

[0103] The inventors have further detected the product of the reaction between the compound of formula (Id) and DECP and the compound of formula (Ii) formed in the reaction of TMSBr:

[0104] [ka]

[0105] wherein each R is as defined for formula (I). The present inventors have surprisingly found that the compound of formula (Ii) can be separated from the product of the deprotection reaction, i.e., from the compound of formula (I), in the process of crystallization of the compound of formula (I).

[0106] Therefore, the present invention further relates to an embodiment in which the crude product according to formula (I) thus obtained, which may contain further impurities, including, according to the inventors, the compound of formula (Ih) and / or the compound of formula (II), is recrystallized or reslurried, preferably from water / acetone. Thus, the crude product of formula (I) of the present invention described herein is slurried in water / acetone and refluxed at a temperature of 60° C. The recrystallized / reslurried mixture is then allowed to cool to a temperature of about 20° C., and the precipitate formed is filtered off, washed with water / acetone (1:1) and with acetone, and dried under vacuum.

[0107] In one embodiment of the present invention, the method of the present invention comprises the step of reacting a compound of formula (Ic):

[0108] [ka]

[0109] wherein each R is as defined for formula (I), to provide a compound of formula (Id).

[0110] Several reducing agents suitable for reducing keto and amide groups can be used in this embodiment of the method of the present invention. Thus, in one embodiment, LAH (also referred to as LiAlH) is used in the reduction reaction. Preferably, in this particular embodiment, the reduction is carried out in toluene, dioxane, or CPME. More preferably, the reduction is carried out in toluene, preferably under reflux.

[0111] In the reaction of ketoamide (Ic) with LAH, in the first step, the compound of formula (Ic) is charged into a reactor together with toluene, and any remaining water is removed by azeotropic distillation of toluene / water. Once the distillation is complete and the reaction mixture is cooled to a temperature between 55°C and 65°C, preferably to about 60°C, more preferably to 60°C, a solution of LAH in THF (preferably a 2.0M to 3.0M solution, particularly a 2.4M solution) is added. As known to those skilled in the art, during the addition of LAH, both heat and gaseous hydrogen will be liberated from the reaction mixture. Thus, it will be clear to those skilled in the art that care should be taken in the process to avoid elevated hydrogen concentrations, for example, by controlled dosing of the LAH addition and / or by including a light stream of gas, such as nitrogen.

[0112] The reaction of the compound of formula (Ic) with the reducing agent is preferably carried out until a specific desired fraction of the compound has reacted. This should be understood to be equivalent to a specific fraction of the compound being consumed, regardless of the reaction undergone by the compound. Preferably, the reaction should be carried out until at least 90%, at least 95%, or 99% of the compound has reacted. More preferably, the reaction should be carried out until at least 99% of the compound has reacted. Preferably, the progress of the reaction is monitored by using LC-MS or GC-MS analysis on a sample from the reaction mixture.

[0113] Once a specific desired fraction of the compound of formula (Ic) is consumed, as described above, preferably an additional volume of toluene is added to the reactor to further concentrate the reaction mixture. A saturated solution of sodium potassium tartrate is then added. The composition thus obtained is stirred, preferably at a temperature of about 40 ° C, to separate the organic phase from the aqueous phase. The aqueous phase is washed with toluene (preferably several times, for example, four times) so that it can be extracted. The toluene phases thus obtained are combined, washed with a half-saturated sodium potassium tartrate solution, incubated with activated carbon, dried over sodium sulfate, and / or filtered through Celite.

[0114] The product is then preferably crystallized from isopropyl acetate / n-heptane. The organic phase is then concentrated and isopropyl acetate / n-heptane is added. Crystallization is induced by seeding, whereby the temperature is lowered first to 0°C and then to -30°C. The crystallized compound of formula (Id) is isolated by filtration under reduced pressure, and the resulting filtrate is then dried under vacuum.

[0115] According to the present inventors, a compound of formula (Ij):

[0116] [ka]

[0117] wherein each R is as defined for formula (I) may be formed during the reduction of a compound of formula (Ic). The inventors have however surprisingly found that a compound of formula (Ij) can be separated from a compound of formula (Id) in a process of crystallization from isopropyl acetate / n-heptane. Furthermore, according to the present invention, it has been hypothesized that this compound, as an intermediate in the reduction, requires higher temperatures for further reduction / conversion. Therefore, and preferably, temperatures are required that can be obtained by boiling toluene, dioxane, or CPME. The temperatures correspond to the boiling points of toluene, dioxane, or CPME, respectively.

[0118] In another particular embodiment of the present invention, the compound of formula (Ic) is reduced by using NaBH4.

[0119] In another embodiment, the present invention relates to a method of the present invention, wherein the method further comprises the step of reacting a compound of formula (Ia):

[0120] [ka]

[0121] with (COCl) followed by reaction of the resulting product with RNH, where each R is as defined for formula (I).

[0122] Preferably, the reaction should be carried out in CPME as a solvent, in which both oxalyl chloride and the compound of formula (Ia) should be dissolved. In this reaction, it is preferable to use an excess of oxalyl chloride relative to the compound of formula (Ia), for example, at least a 1.1 molar ratio, at least a 1.5 molar ratio, or at least a 2.0 molar ratio of oxalyl chloride relative to the compound of formula (Ia). Particularly preferred is the use of a molar ratio of about 1.5, more preferably 1.5, of oxalyl chloride relative to the compound of formula (Ia). Preferably, the excess oxalyl chloride should be supplied throughout the entire reaction period. Therefore, it is preferred to add, for example, dropwise, a solution of the compound of formula (Ia) to a solution of oxalyl chloride.

[0123] The temperature of the reaction should preferably be controlled, and preferably the reaction between oxalyl chloride and the compound of formula (Ia) should be carried out at a temperature below 20°C, preferably between 0°C and 20°C, more preferably between 0°C and 10°C.

[0124] The progress of the reaction is preferably controlled by monitoring the compound of formula (Ia). Thus, the reaction between oxalyl chloride and the compound of formula (Ia) is preferably carried out until a specific desired fraction of the compound has reacted. This should be understood as equivalent to a specific fraction of the compound being consumed, regardless of the reaction undergone by the compound. Preferably, the reaction should be carried out until at least 90%, at least 95%, or 99% of the compound has reacted. More preferably, the reaction should be carried out until at least 99% of the compound has reacted. Preferably, the progress of the reaction is monitored by using LC-MS analysis or GC-MS analysis on a sample from the reaction mixture.

[0125] Preferably, once a particular desired fraction of the compound of formula (Ia) has reacted, the reaction mixture is diluted with a solvent, preferably CPME, as described above, and the solvent is distilled off from the reaction mixture, simultaneously removing oxalyl chloride.

[0126] Preferably, n-heptane is added to the reaction mixture at a temperature preferably below 20° C., preferably between 0° C. and 20° C., more preferably between 0° C. and 10° C., even more preferably at a temperature of about 0° C., even more preferably at a temperature of 0° C. As a result, the product of the reaction of the compound of formula (Ia) with oxalyl chloride precipitates and is separated by filtration and then washed with n-heptane. The filtrate thus obtained is dried by exposure to a stream of nitrogen.

[0127] According to the inventors, the reaction of a compound of formula (Ia) with oxalyl chloride gives a compound of formula (Ib):

[0128] [ka]

[0129] This results in the compound:

[0130] As understood herein, according to the inventors, the product of the reaction of a compound of formula (Ia) with oxalyl chloride, which may be a compound of formula (Ib), should be reacted with an amine of formula RNH, where each R is as defined for formula (I), to obtain a compound of formula (Ic).

[0131] Preferably, the reaction should be carried out in 2-MeTHF. Thus, the product of the reaction of the compound of formula (Ia) with oxalyl chloride can be directly dissolved in 2-MeTHF while still in the filter funnel upon filtration and drying under nitrogen. Both substrates dissolved in the solvent can be stirred together, and the progress of the reaction is monitored. The product of the reaction of the compound of formula (Ia) with oxalyl chloride is preferably added to the amine at a temperature between -10 and 5°C. Once a certain fraction of the product of the reaction of the compound of formula (Ia) with oxalyl chloride has reacted (e.g., at least 90%, at least 95%, or at least 99%), the reaction is stopped by adding 1N aqueous HCl to the reaction mixture. Phase separation follows, and the separated organic phase is washed with aqueous HCl, for example, 0.5M HCl solution. The aqueous phase thus formed is then washed with 2-MeTHF, and the combined organic phases are washed with water, incubated with activated charcoal, and filtered through Celite.

[0132] The solution thus obtained is concentrated to initiate crystallization of the product, thereby lowering the temperature to −20° C. The precipitated product of formula (Ic) is filtered, washed with 2-MeTHF, 2-MeTHF / n-heptane (preferably 1:1 v / v) and n-heptane, and dried under vacuum.

[0133] In embodiments of the present invention in which a compound of formula (Id) is reacted with DECP, the DECP is a compound of formula (R'O)2POCl, where each R' is independently 1-6 alkyl, -CH2-aryl or -CH2-heteroaryl, preferably each R' is independently selected from C 1-6 alkyl and -CH2-aryl, more preferably each R' is independently selected from C 1-6It should be understood that those skilled in the art will recognize that the compound of formula (Id) can be replaced with a compound of formula (R'O)2POCl (wherein each R' is independently C 1-6 alkyl, -CH2-aryl or -CH2-heteroaryl, preferably C 1-6 alkyl and -CH2-aryl, more preferably each R' is independently selected from C 1-6 In particular, C 1-6 The alkyl groups are ethyl and tert-butyl. A particularly suitable -CH2-aryl is benzyl.

[0134] As used herein, the term "alkyl" refers to a monovalent saturated acyclic (i.e., non-cyclic) hydrocarbon group that may be straight-chained or branched. Thus, an "alkyl" group does not contain any carbon-carbon double bonds or any carbon-carbon triple bonds. 1-6 "Alkyl" refers to an alkyl group having from 1 to 6 carbon atoms. Preferred exemplary alkyl groups are methyl, ethyl, propyl (e.g., n-propyl or isopropyl), or butyl (e.g., n-butyl, isobutyl, sec-butyl, or tert-butyl). Unless otherwise defined, the term "alkyl" preferably refers to a C 1-4 It refers to alkyl, more preferably methyl or ethyl, and even more preferably methyl. Those skilled in the art will be aware of the abbreviations typically used for various alkyl groups, such as Me for methyl, Et for ethyl, Bu for butyl, or tBu for tert-butyl.

[0135] As used herein, the term "aryl" refers to aromatic hydrocarbon ring groups, including monocyclic aromatic rings and bridged and / or fused ring systems containing at least one aromatic ring (e.g., a ring system consisting of two or three fused rings, where at least one of the fused rings is aromatic, or a bridged ring system consisting of two or three rings, where at least one of the bridged rings is aromatic). "Aryl" can refer to, for example, phenyl, naphthyl, diarylnyl (i.e., 1,2-dihydronaphthyl), tetralinyl (i.e., 1,2,3,4-tetrahydronaphthyl), indanyl, indenyl (e.g., 1H-indenyl), anthracenyl, phenanthrenyl, 9H-fluorenyl, or azulenyl. Unless otherwise defined, "aryl" preferably has 6 to 14 ring atoms, more preferably 6 to 10 ring atoms, and even more preferably refers to phenyl or naphthyl, and most preferably refers to phenyl.

[0136] As used herein, the term "heteroaryl" refers to aromatic ring groups, including monocyclic aromatic rings and bridged and / or fused ring systems containing at least one aromatic ring (e.g., a ring system composed of two or three fused rings, wherein at least one of the fused rings is aromatic, or a bridged ring system composed of two or three rings, wherein at least one of the bridged rings is aromatic), wherein the aromatic ring group contains one or more (e.g., one, two, three, or four, etc.) ring heteroatoms independently selected from O, S, and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) can be optionally oxidized, and further one or more carbon ring atoms can be optionally oxidized (i.e., to form an oxo group). For example, each heteroatom-containing ring contained in the aromatic ring group may contain one or two O atoms and / or one or two S atoms (which may be optionally oxidized) and / or one, two, three, or four N atoms (which may be optionally oxidized), provided that the total number of heteroatoms in the corresponding heteroatom-containing ring is 1 to 4 and there is at least one carbon ring atom (which may be optionally oxidized) in the corresponding heteroatom-containing ring. "Heteroaryl" includes, for example, thienyl (i.e., thiophenyl), benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl (i.e., furanyl), benzofuranyl, isobenzofuranyl, chromanyl, chromenyl (e.g., 2H-1-benzopyranyl or 4H-1-benzopyranyl), isochromenyl (e.g., 1H-2-benzopyranyl), chromonyl, xanthenyl, phenoxathiinyl, pyrrolyl (e.g., 1H-pyrrolyl), imidazolyl, pyrazolyl, pyridyl (i.e., pyridinyl; e.g., 2-pyridyl, 3-pyridyl, or 4-pyridyl), pyrazinyl, pyrimidinyl, pyridazinyl, indolyl (e.g., 3H-indolyl), isoindolyl, indazolyl, indolizinyl, purinyl, quinolyl, isoquinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, cinnolinyl, pteridinyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl (e.g., [1,10]phenanthrolinyl, [1,7]phenanthrolinyl, or [4,7]phenanthrolinyl), phenazinyl, thiazolyl, isothiazolyl, phenothiazinyl, oxazolyl, isoxazolyl, oxadiazolyl (e.g., For example, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl (i.e., furazanyl), or 1,3,4-oxadiazolyl), thiadiazolyl (e.g., 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, or 1,3,4-thiadiazolyl), phenoxazinyl, pyrazolo[1,5-a]pyrimidinyl (e.g., pyrazolo[1,5-a]pyrimidin-3-yl), 1,2-benzisoxazol-3-yl, benzothiazolyl, benzothiadiazolyl, benzoxazolyl, benzisoxazolyl, benzimidazolyl , benzo[b]thiophenyl (i.e., benzothienyl), triazolyl (e.g., 1H-1,2,3-triazolyl, 2H-1,2,3-triazolyl, 1H-1,2,4-triazolyl, or 4H-1,2,4-triazolyl), benzotriazolyl, 1H-tetrazolyl, 2H-tetrazolyl, triazinyl (e.g., 1,2,3-triazinyl, 1,2,4-triazinyl, or 1,3,5-triazinyl), furo[2,3-c]pyridinyl, dihydrofuropyridinyl (e.g., 2,3-dihydrofuro[2,3-c]pyridinyl or 1,3-dihydrofuro[3,4-c]pyridinyl), imidazopyridinyl (e.g., imidazo[1,2-a]pyridinyl or imidazo[3,2-a]pyridinyl), quinazolinyl, thienopyridinyl, tetrahydrothienopyridinyl (e.g., 4,5,6,7-tetrahydrothieno[3,2-c]pyridinyl), dibenzofuranyl, 1,3-benzodioxolyl, benzodioxanyl (e.g., 1,3-benzodioxanyl or 1,4-benzodioxanyl), or coumarinyl. Unless otherwise defined, the term "heteroaryl" preferably refers to a 5- to 14-membered (more preferably 5- to 10-membered) monocyclic ring or fused ring system containing one or more (e.g., one, two, three, or four) ring heteroatoms independently selected from O, S, and N, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) can be optionally oxidized, and one or more carbon ring atoms can be optionally oxidized; even more preferably, "heteroaryl" refers to a 5- or 6-membered monocyclic ring containing one or more (e.g., one, two, or three) ring heteroatoms independently selected from O, S, and N, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) can be optionally oxidized, and one or more carbon ring atoms can be optionally oxidized.

[0137] That is, the process of the present invention for preparing compounds of formula (I) comprises reacting a compound of formula (Id):

[0138] [ka]

[0139] wherein each R is as defined for formula (I). The compound of formula (R'O)2POCl (wherein each R' is independently 1-6 alkyl, -CH2-aryl or -CH2-heteroaryl, preferably each R' is independently selected from C 1-6alkyl and -CH2-aryl, more preferably each R' is independently selected from C 1-6 The reaction may include reacting with a C 1-6 The alkyl group is methyl, ethyl, and tert-butyl. A particularly suitable -CH-aryl is benzyl. That is, in the method of the present invention, particularly preferred compounds (R'O)POCl are (MeO)POCl, (EtO)POCl, (tBuO)POCl, and (benzyl-O)POCl, more preferably (EtO)POCl, (tBuO)POCl, and (benzyl-O)POCl, even more preferably (EtO)POCl, and (tBuO)POCl, and even more preferably (EtO)POCl (also referred to as DECP).

[0140] Preferably, within the scope of the present invention, the product of the reaction of the compound of formula (Id) with said (R'O)2POCl (preferably DECP) is further reacted with TMSBr as described above to give the compound of formula (I), which reaction may also be referred to herein as the deprotection reaction.

[0141] That is, the present invention provides a compound of formula (I):

[0142] [ka]

[0143] wherein each R independently represents C 1-6 alkyl, preferably methyl or ethyl), wherein the method comprises reacting a compound of formula (Id):

[0144] [ka]

[0145] The compound of formula (R'O)2POCl (wherein each R' is independently 1-6wherein the product of the reaction of the compound of formula (Id) with (R'O)POCl is further reacted with TMSBr to provide a compound of formula (I).

[0146] While the method is detailed herein for an embodiment where both R' are ethyl, the method of the present invention extends to the entire provided range of R', i.e., C 1-6 Those skilled in the art will recognize that generalizations can be made for R' to be alkyl, -CH2-aryl, or -CH2-heteroaryl. Particularly preferred is the embodiment of the invention in which both R' are ethyl, and for which the invention is exemplified.

[0147] Additionally, the compound of formula (Id) (R'O)2POCl, wherein each R' is independently 1-6 It will be clear to those skilled in the art that the product of the reaction with (R'O)2POH, selected from alkyl, -CH2-aryl and -CH2-heteroaryl, can also be obtained under different conditions, for example by reacting the compound of formula (Id) with (R'O)2POH under conditions leading to the presence of (R'O)2POCl, for example in the presence of a base and carbon tetrachloride, as described in WO 2022 / 016289, or (R'O)2POCl being generated in situ in the presence of NCS (N-chlorosuccinimide) and THF. Thus, in the present description, the term (R'O)2POCl (wherein each R' is independently C 1-6 alkyl, -CH2-aryl and -CH2-heteroaryl (preferably independently C 1-6 alkyl and -CH-aryl, more preferably independently selected from C 1-6 When referring to a product obtainable by reaction of a compound of formula (Id) with (R'O)2POCl, where each R' is independently C 1-6The compounds of formula (Id) are not limited to the products obtained in the reaction of a compound of formula (Id) with (R'O)2POOH under conditions leading to the presence of (R'O)2POCl, as described in WO 2022 / 016289, but also include those obtained in any other way, for example by reacting a compound of formula (Id) with (R'O)2POOH under conditions leading to the presence of (R'O)2POCl.

[0148] The inventors believe, without being bound by theory, that said product, when it can be obtained in the reaction of a compound of formula (Id) with DECP, has the formula:

[0149] [ka]

[0150] Each R is as defined for formula (I), preferably each R is independently methyl or ethyl.

[0151] Furthermore, the inventors have discovered that the product can be obtained by reacting a compound of formula (Id) with (R'O)2POCl, as defined above, and has the formula (Ie-1):

[0152] [ka]

[0153] or a salt thereof (e.g., an HCl salt), wherein each R is as defined for formula (I), preferably each R is independently methyl or ethyl, and each R' is as defined for (R'O)2POCl.

[0154] Therefore, in view of the above, the present invention provides, in one embodiment, a compound of formula (I):

[0155] [ka]

[0156] wherein each R independently represents C 1-6 alkyl, preferably methyl or ethyl), The method comprises reacting a compound of formula (Id):

[0157] [ka]

[0158] (R'O)2POCl (wherein each R' is independently 1-6 The method comprises reacting the product obtainable in the reaction with a -C-alkyl group (selected from -C-alkyl, -CH2-aryl and -CH2-heteroaryl) with TMSBr to give a compound of formula (I).

[0159] Preferably, each R' is independently C 1-6 More preferably, each R' is independently selected from -C 1-6 Even more preferably, both R' are ethyl (in other words, each R' is ethyl).

[0160] Further examples and / or embodiments of the present invention are disclosed in the following numbered items:

[0161] 1. Formula (I):

[0162] [ka]

[0163] 1. A method for preparing a compound of the formula wherein each R is independently methyl or ethyl; wherein the method comprises reacting a compound of formula (Id):

[0164] [ka]

[0165] with (EtO)2POCl(DECP).

[0166] 2. The method of item 1, wherein each R is methyl.

[0167] 3. The process of item 1 or 2, wherein the w / w ratio of the compound of formula (Id) and (DECP) is between 0.8 and 1.2, preferably between 1.0 and 1.2, more preferably between 1.10 and 1.15, even more preferably about 1.12, even more preferably 1.12.

[0168] 4. The method of any one of items 1 to 3, wherein the DECP is administered dropwise over a period of between 10 and 20 minutes.

[0169] 5. The process of any one of items 1 to 4, wherein the reaction of the compound of formula (Id) with DECP is carried out in acetonitrile.

[0170] 6. The process of any one of items 1 to 5, wherein the reaction of the compound of formula (Id) with DECP is carried out at a temperature between 50°C and 70°C, preferably between 55°C and 65°C, more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, even more preferably at a temperature of 60°C.

[0171] 7. The process of any one of items 1 to 6, wherein the reaction of the compound of formula (Id) with DECP is carried out in the presence of a base, preferably wherein the base is N-ethyldiisopropylamine.

[0172] 8. The process of any one of items 1 to 7, wherein the reaction of the compound of formula (Id) with DECP is carried out for a period of at least 150 minutes, until at least 99% of the compound of formula (Id) has reacted.

[0173] 9. The process of any one of items 1 to 8, wherein upon reaction of the compound of formula (Id) with DECP, the solvent is changed to toluene and an aqueous NaOH solution is added thereto, followed by phase separation.

[0174] 10. The method of item 8, wherein NaOH is added at a concentration of 0.5M to 1.0M, preferably at a concentration of about 0.75M, more preferably at a concentration of 0.75M.

[0175] 11. The process of any one of items 1 to 10, wherein upon completion of the reaction of the compound of formula (Id) with DECP, the solvent is changed to CPME, and HCl in CPME is added to the reaction mixture, which leads to precipitation of the crude product.

[0176] 12. The process of item 11, wherein the HCl in CPME is about a 3M solution, and / or said solution is added dropwise over a period of between 25 and 35 minutes, and / or said solution is added at a temperature between 15°C and 20°C, preferably at a temperature between 17°C and 23°C, more preferably at a temperature of about 20°C, even more preferably at a temperature of 20°C.

[0177] 13. The reaction of a compound of formula (Id) with DECP gives a compound of formula (Ie):

[0178] [ka]

[0179] 13. The process of any one of items 1 to 12, wherein the crude product is

[0180] 14. The process of any one of items 1 to 13, wherein the crude product precipitated from CPME upon addition of HCl comprises a compound of formula (Ie).

[0181] 15. The process of any one of items 1 to 14, wherein the product of the reaction of the compound of formula (Id) with DECP is further reacted with TMSBr to provide the compound of formula (I).

[0182] 16. The process of item 15, wherein the w / w ratio of TMSBr to the compound of formula (Id) is between 1.5 and 2.5, preferably between 1.8 and 2.4, more preferably between 2.0 and 2.3, even more preferably about 2.0, even more preferably 2.07.

[0183] 17. The method of item 15 or 16, wherein the product of the reaction of the compound of formula (Id) with DECP is reacted with TMSBr in acetonitrile.

[0184] 18. The process of any one of items 15 to 17, wherein TMSBr is added at a temperature between 30°C and 50°C, preferably between 35°C and 45°C, more preferably between 37°C and 43°C, even more preferably at a temperature of about 40°C, even more preferably at a temperature of 40°C.

[0185] 19. The process of any one of items 15 to 18, wherein the product of the reaction of the compound of formula (Id) with DECP is reacted with TMSBr at a temperature between 50°C and 70°C, preferably between 55°C and 65°C, more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, even more preferably at a temperature of 60°C.

[0186] 20. The process of any one of items 15 to 19, wherein the reaction with TMSBr is carried out for at least 150 minutes until at least 99% of the product of the reaction of the compound of formula (Id) with DECP is consumed.

[0187] 21. The method of any one of items 15 to 20, wherein in the reaction with TMSBr, the solvent is changed to methanol.

[0188] 22. The process of any one of items 15 to 21, wherein the obtained product of the reaction with TMSBr is subjected to a solvent change to water, wherein the pH of the solution is set to a value ranging between pH=3.8 and pH=4.2, preferably through the addition of 1 M NaOH.

[0189] 23. The process of item 22, wherein the w / w ratio of 1M NaOH solution to the original amount of compound of formula (Id) added is about 4.0, preferably 4.0.

[0190] 24. The method of item 22 or 23, wherein the final product of formula (I) precipitates from aqueous solution at a pH between 3.8 and 4.2 and / or at a temperature below 20°C, preferably at a temperature of about 15°C, more preferably at a temperature of 15°C.

[0191] 25. The process of any one of items 1 to 24, wherein the final product of formula (I) is reslurried upon treatment with water / acetone under reflux.

[0192] 26.Formula (Ic):

[0193] [ka]

[0194] 26. The process of any one of items 1 to 25, further comprising the step of reducing the compound of formula (Id) to give a compound of formula (Id).

[0195] 27. The method of item 26, wherein LAH is used as a reducing agent in the step of reducing the compound of formula (Ic) to give the compound of formula (Id).

[0196] 28. The step of reducing a compound of formula (Ic) to give a compound of formula (Id) is carried out in toluene, in dioxane or in CPME, preferably in toluene; Preferably, the process according to item 27, wherein the process is carried out under reflux.

[0197] 29. The method of item 26, wherein NaBH4 is used as a reducing agent in the step of reducing the compound of formula (Ic) to give the compound of formula (Id).

[0198] 30. The method further comprises:

[0199] [ka]

[0200] with (COCl)2, followed by reaction of the resulting product with R2NH.

[0201] 31. The method of item 30, wherein the reaction of the compound of formula (Ia) with (COCl)2 is carried out in CPME at a temperature between 0°C and 10°C.

[0202] 32. The reaction of a compound of formula (Ia) with (COCl)2 gives a compound of formula (Ib):

[0203] [ka]

[0204] resulting in a compound of 32. The method of item 30 or 31, wherein the compound of formula (Ib) is reacted with R2NH to give a compound of formula (Ic).

[0205] Further examples and embodiments of the present invention are disclosed in the following numbered paragraphs.

[0206] 1. Formula (I):

[0207] [ka]

[0208] 1. A method for preparing a compound of formula (I), comprising: wherein each R is independently methyl or ethyl; wherein the method comprises reacting a compound of formula (Id):

[0209] [ka]

[0210] with (EtO)2POCl(DECP).

[0211] 2. The method of paragraph 1, wherein each R is methyl.

[0212] 3. The w / w ratio of the compound of formula (Id) and (DECP) is between 0.8 and 1.2, preferably between 1.0 and 1.2, more preferably between 1.10 and 1.15, even more preferably about 1.12, even more preferably 1.12; Preferably, the method of paragraph 1 or 2, wherein the DECP is added dropwise over a period of between 10 and 20 minutes.

[0213] 4. The reaction of the compound of formula (Id) with DECP is carried out in acetonitrile; Preferably, the reaction of the compound of formula (Id) with DECP is carried out at a temperature between 50°C and 70°C, more preferably between 55°C and 65°C, even more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, even more preferably at a temperature of 60°C; and / or the reaction of the compound of formula (Id) with DECP is carried out in the presence of a base, preferably wherein the base is N-ethyldiisopropylamine; and / or 4. The method of any one of paragraphs 1 to 3, wherein the reaction of the compound of formula (Id) with DECP is carried out for a period of at least 150 minutes, until at least 99% of the compound of formula (Id) has reacted.

[0214] 5. Upon reaction of the compound of formula (Id) with DECP, the solvent is changed to toluene and an aqueous solution of NaOH is added thereto, followed by phase separation; Preferably, NaOH is added at a concentration of 0.5M to 1.0M, more preferably at a concentration of about 0.75M, even more preferably at a concentration of 0.75M; and / or Upon completion of the reaction of the compound of formula (Id) with DECP, the solvent is changed to CPME and HCl in CPME is added to the reaction mixture, which leads to the precipitation of the crude product, 5. The method of any one of paragraphs 1 to 4, wherein preferably the HCl in CPME is about a 3 M solution, and / or the solution is added dropwise over a period of between 25 and 35 minutes, and / or the solution is added at a temperature between 15° C. and 20° C., preferably between 17° C. and 23° C., more preferably at a temperature of about 20° C., even more preferably at a temperature of 20° C.

[0215] 6. Reaction of a compound of formula (Id) with DECP gives a compound of formula (Ie):

[0216] [ka]

[0217] yielding a crude product of Preferably, the crude product precipitated from CPME upon addition of HCl comprises a compound of formula (Ie).

[0218] 7. The product of the reaction of the compound of formula (Id) with DECP is further reacted with TMSBr to give the compound of formula (I), Preferably, wherein the w / w ratio of TMSBr to compound of formula (Id) is between 1.5 and 2.5, more preferably between 1.8 and 2.4, even more preferably between 2.0 and 2.3, even more preferably about 2.0, even more preferably 2.07; Preferably, the process of any one of paragraphs 1 to 6, wherein the product of the reaction of the compound of formula (Id) with DECP is reacted with TMSBr in acetonitrile.

[0219] 8. TMSBr is added at a temperature between 30°C and 50°C, preferably between 35°C and 45°C, more preferably between 37°C and 43°C, even more preferably at a temperature of about 40°C, even more preferably at a temperature of 40°C; and / or the product of the reaction of the compound of formula (Id) with DECP is reacted with TMSBr at a temperature between 50°C and 70°C, preferably between 55°C and 65°C, more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, even more preferably at a temperature of 60°C; and / or 8. The process of item 7, wherein the reaction with TMSBr is carried out for at least 150 minutes until the product of the reaction of the compound of formula (Id) with DECP is at least 99% consumed.

[0220] 9. When reacting with TMSBr, the solvent was changed to methanol. and / or 9. The process of item 7 or 8, wherein the obtained product of said reaction with TMSBr is subjected to a solvent change to water, wherein the pH of the solution is set to a value ranging between pH=3.8 and pH=4.2, preferably through the addition of 1M NaOH, preferably wherein the w / w ratio of 1M NaOH solution to the original amount of compound of formula (Id) added is about 4.0, more preferably 4.0, and preferably wherein the final product of formula (Id) precipitates from the aqueous solution at a pH between 3.8 and 4.2 and / or at a temperature below 20°C, preferably at a temperature of about 15°C, more preferably at a temperature of 15°C.

[0221] 10. The process of any one of paragraphs 1 to 9, wherein the final product of formula (I) is reslurried upon treatment with water / acetone under reflux.

[0222] 11.Formula (Ic):

[0223] [ka]

[0224] 11. The method of any one of paragraphs 1 to 10, further comprising reducing a compound of formula (Id) to provide a compound of formula (Id).

[0225] 12. In the step of reducing a compound of formula (Ic) to give a compound of formula (Id), LAH is used as a reducing agent; Preferably, wherein the step of reducing a compound of formula (Ic) to give a compound of formula (Id) is carried out in toluene, in dioxane or in CPME, preferably in toluene, Preferably, the process according to item 11, wherein the step is carried out under reflux.

[0226] 13. The method of item 11, wherein NaBH4 is used as a reducing agent in the step of reducing the compound of formula (Ic) to give the compound of formula (Id).

[0227] 14. The method further comprises reacting a compound of formula (Ia):

[0228] [ka]

[0229] 14. The method of any one of paragraphs 11 to 13, comprising reacting the compound of formula (I) with (COCl)2, followed by reaction of the resulting product with R2NH.

[0230] 15. The reaction of a compound of formula (Ia) with (COCl)2 is carried out in CPME at a temperature between 0°C and 10°C; and / or The reaction of the compound of formula (Ia) with (COCl)2 gives the compound of formula (Ib):

[0231] [ka]

[0232] resulting in a compound of Item 15. The method of item 14, wherein the compound of formula (Ib) is reacted with R2NH to give a compound of formula (Ic).

[0233] The invention is illustrated by the following examples which, however, should not be construed as limiting. [Example]

[0234] Example 1: Preparation of etosibine according to the present invention. A scale-up method for the preparation of etosibine according to the present invention will now be described below.

[0235] Step 1: Process for the preparation of acetoxyindole oxacetyl chloride from 4-acetoxyindole in the setup outlined in Figure 1 Part 1. Process 1a : Preparation of a solution of oxalyl chloride in cyclopentyl methyl ether (CPME) in a 5 liter glass reactor vessel as shown in FIG. Preparation of a solution of 4-acetoxyindole (1 volume) in 5 volumes of CPME (preferably performed in a 2 L glass bottle). The 4-acetoxyindole solution was slowly added to the oxalyl chloride solution under stirring. Stirring was maintained until sufficient 4-acetoxyindole was converted to acetoxyindole oxacetyl chloride. The reaction mixture was then concentrated under reduced pressure and repeatedly diluted with CPME and subjected to subsequent distillation (at least twice).

[0236] The resulting suspension was then diluted with n-heptane and further stirred at 0° C. in the reaction vessel shown in FIG. 1, Part 1 (position 2). The product suspension was filtered using a 1-liter glass filter and washed twice with 2.5 volumes of n-heptane. The filter cake was then dried under a light stream of nitrogen gas.

[0237] The mass flow rate and mass balance chart is shown in Figure 1, Part 3.

[0238] Process 1bThe acetoxyindole oxacetyl chloride from step 1a was then dissolved in 16.9 volumes of 2-methyltetrahydrofuran (2-MeTHF) in a 5 liter glass reaction vessel and mixed with a solution of 2.1 equivalents of diethylamine in 2-MeTHF (1 volume of diethylamine and 2 volumes of 2-MeTHF) in a second 5 liter glass reaction vessel in the setup outlined in Figure 1 part 2.

[0239] The mixture was then further stirred until sufficient acetoxyindole-oxoacetyl chloride had reacted. 4.5 volumes of 1N HCl solution were then added to the reaction mixture. A phase separation step was then performed, whereby the upper organic phase was then separated. The organic phase was then washed again with 4.5 volumes of 0.5M HCl. The combined aqueous washing solutions were then extracted twice with 4.5 volumes of 2-MeTHF and subsequently with 2.3 volumes of deionized water. Activated carbon (12.5 g) was then added to the organic phase under stirring, and the mixture was then filtered over 100 g of Celite (e.g., Celpure™). The organic phase thus obtained was concentrated under vacuum and subjected to a cooling ramp at a temperature of -20°C to obtain a suspension of the product (seeding of the precipitate may be necessary to obtain a suspension). The suspension was then filtered. The filter cake thus obtained was then washed twice with 1.4 volumes of 2-methyltetrahydrofuran (MeTHF). The organic phase containing acetoxyindole glyoxylic acid diethylamide was then further concentrated under vacuum to obtain 163 g of acetoxyindole glyoxylic acid diethylamide.

[0240] Mass flow rate and mass balance charts are shown in Figure 1, parts 4 and 5.

[0241] The analytical data for the resulting product is shown in FIG.

[0242] HPLC measurements were carried out according to the following protocol.

[0243] JPEG2025531381000039.jpg84158

[0244] The HPLC data is shown in Figure 5, part 1.

[0245] LC-MS was performed using a mobile phase A of ACN:water 1:1, using a restricted capillary with a precolumn, at a flow rate of 0.5 ml (5 min). Detection was performed at a wavelength of 220 nm. LC-MS measurements (Figure 5, parts 2 and 3) showed the presence of two peaks: 303.2 m / z: [M+H] + and 605.4 m / z: [2M+H] + Further details regarding the LC-MS measurements are as follows. a. Thermofisher Vanquish ISQ Family (single quadrupole) b. Heated electrospray ionization (HESI): positive mode (3000 V; 50 μA); ion transfer tube temperature 300°C; vaporizer temperature 282°C.

[0246] 1 The H NMR spectrum was measured at 400 MHz in DMSO-d6 using a Bruker Avance 400 spectrometer. The spectrum is shown in Figure 5, part 4, and the observed peaks are summarized below.

[0247] JPEG2025531381000040.jpg57158

[0248] 13 The C NMR spectrum was measured at 125 MHz in DMSO-d6 using a Bruker Avance 400 spectrometer. The spectrum is shown in Figure 5, part 5, and the observed peaks are summarized below.

[0249] JPEG2025531381000041.jpg187154

[0250] DSC measurements were performed using a Mettler Toledo Thermal Analysis DSC3+ and aluminum crucibles (40 μL). DSC screening was typically performed as follows: 20–300 °C, 10 °C / min, 1.00 sec data points. DSC measurements are shown in Figure 5, part 6.

[0251] Step 2: Process for the preparation of 4-hydroxy-indole-3-ethyl-diethylamide (4-HO-DET) from acetoxyindole glyoxylic acid diethylamide in the setup outlined in Figure 2 part 1. The ketoamide (100 g) from step 1b was then combined with 15 volumes of toluene in a 5-liter glass reaction vessel under a nitrogen atmosphere. Azeotropic distillation of toluene / water was then carried out at 950 to 850 mbar with stirring (50 to 250 rpm) at a jacket temperature (Ta) of 130±5°C, resulting in approximately 3 volumes of distillate (1). The solution was then allowed to cool to 60°C, which led to the precipitation of the product and the formation of a suspension. 370 mL of lithium aluminum hydride (LAH) (2.4 M) in tetrahydrofuran (THF) was then slowly added with stirring (50 to 250 rpm) at a temperature of 60 to 70°C. The reaction The mixture was then heated to a temperature of 120°C under reflux and stirring (50 to 250 rpm) for at least 3 hours. The reaction mixture was then further stirred without refluxing, and the amount of reacted ketoamide was determined as an in-process control step. Toluene was again added to concentrate the reaction mixture. The reaction mixture was cooled to below 55°C. A saturated solution of potassium sodium tartrate was added, and the reaction mixture was stirred (50 to 250 rpm) at a temperature of 40±3°C for at least 30 minutes. A phase separation step was then carried out. The aqueous phase was extracted four times with toluene, whereby the aqueous phase was extracted four times with toluene. The combined organic phases were washed with half-saturated potassium sodium tartrate solution. The aqueous phase was then back-extracted with toluene, and the resulting toluene extract was added to the combined organic phase extracted with the potassium sodium tartrate solution. Activated carbon was then added to the organic phase under stirring. The mixture was then dried over sodium sulfate and clarified by filtration through Celite (e.g., Celpure™) using a 3-liter glass filter. The filtrate was then further dried over sodium sulfate and filtered again through Celite (e.g., Celpure™). The organic phase was then further concentrated. Isopropyl acetate and n-heptane were then charged. The mixture was then allowed to cool. Crystallization in the reaction mixture then began, and the jacket temperature (Ta) was lowered to 0°C for 30±5 minutes, and then again to -30°C for 600±30 minutes. The product suspension was then filtered, and the resulting filter cake was diluted with isopropyl acetate / n-heptane 1:1. v / v The filter cake was then dried under vacuum.The product, 4-hydroxy-N,N-diethyltryptamine (4-HO-DET), was isolated.

[0252] Mass flow rate and mass balance charts are shown in Figure 2, parts 2 and 3.

[0253] The analytical data for the resulting product is shown in FIG.

[0254] The HPLC measurements, performed as described above, are shown in Figure 6, part 1.

[0255] LC-MS was performed as described above. Measurements (Figure 6, parts 2 and 3) showed 233.3 m / z: [M+H] + The presence of a peak was shown.

[0256] 1 The H NMR spectrum was measured at 400 MHz in DMSO-d6 using a Bruker Avance 400 spectrometer. The spectrum is shown in Figure 6, part 4, and the observed peaks are summarized below.

[0257] JPEG2025531381000042.jpg57159

[0258] 13 The C NMR spectrum was measured at 125 MHz in DMSO-d using a Bruker Avance 400 spectrometer. The spectrum is shown in Figure 6, part 5, and the observed peaks are summarized below.

[0259] JPEG2025531381000043.jpg144154

[0260] The DSC measurements, performed as described above, are shown in FIG.

[0261] Step 3: Process for the preparation of crude ethosibine from 4-HO-diethyltryptamine (4-HO-DET) via DET-diethylphosphate x HCl as intermediate in the setup outlined in Figure 3 part 1. Process 3a : Phosphorylation process 50 g of 4-HO-DET obtained from step 2 was charged into a 1-liter glass reaction vessel shown in FIG. 4 together with 197 g of acetonitrile, and the mixture was then heated to a batch temperature (TI) of 60°C. 55.6 g of N-ethyldiisopropylamine was then added. After the addition of diethyl chlorophosphate, the mixture was further stirred at a TI of 60°C. The amount of remaining 4-HO-DET was determined as an in-process control step. The solvent was then changed to toluene. The reaction mixture was then cooled from room temperature to a TI of 0°C. 0.75 M sodium hydroxide was then added. A phase separation step was then performed, whereby the aqueous phase was extracted twice with toluene. The combined organic phases were washed twice, first with 0.1 N NaOH and then with deionized water. Activated carbon was then added to the organic phase under stirring, then dried over sodium sulfate, and the mixture was clarified by filtration over Celite (e.g., Celpure™ P1000) using toluene in the washing step. The solvent was then changed to cyclopentyl methyl ether (CPME). 3M HCl in CPME was then added, and the suspension was then filtered again over Celite (e.g., Celpure™ P1000) to isolate the intermediate HCl salt. The filter cake was then washed twice with CPME. The amount of resulting TET-diethyl phosphate x HCl was then determined as an in-process control step. The filter cake was then further dried under reduced pressure.

[0262] Process 3b :Deprotection DET-diethyl phosphate x HCl was charged into the reaction vessel in the presence of acetonitrile. The reaction mixture was then heated to a batch temperature (TI) of 40°C. Bromotrimethylsilane was then added, and the reaction mixture was heated to a TI of 60°C under stirring. The amount of remaining DET-diethyl phosphate x HCl was determined as an in-process control step. The solvent was then changed to methanol. The reaction mixture was then stirred at a temperature of 50°C. The solvent was then distilled off. The residue was again mixed with methanol, and the mixture was further stirred at a temperature of 50°C. A solvent change to water was then performed. The pH of the mixture was then adjusted to between 3.8 and 4.2 with 1N NaOH. Isopropanol was charged, and the reaction mixture was then concentrated under reduced pressure. A temperature ramp step was then performed to a jacket temperature (Ta) setpoint of 15°C. The resulting suspension was then filtered. The filter cake was then washed successively, first with deionized water, then with a deionized water / methanol mixture, and finally with methanol alone. The resulting product was then dried under reduced pressure. The resulting product was collected and the yield of crude ethosybin product was then determined.

[0263] The flow mass and mass balance charts are shown in Figure 3, parts 2 to 4.

[0264] The analytical data of the obtained product is shown in FIG.

[0265] The HPLC measurements, performed as described above, are shown in Figure 7, part 1.

[0266] LC-MS was performed as described above. Measurements (Figure 7, parts 2 and 3) showed 313.3 m / z: [M+H] + , 527.4 m / z: [2M-HPO4] + , and 625.4 m / z: [2M+H] + The presence of a peak was shown.

[0267] The DSC measurements, performed as described above, are shown in Figure 7 part 4).

[0268] Step 4: Process for the preparation of etosibine from the crude etosibine product from step 3b in the setup outlined in Figure 4. The etosibine raw product (80 g from step 3b) was loaded into an oxygen-free (inert gas) 1-liter glass reaction vessel, as shown in Figure 5. 40 g of deionized water and 62.5 g of acetone were added sequentially, and the mixture was then stirred (50 to 250 rpm) for at least 16 hours at a jacket temperature setpoint (Ta) of 65 ± 3 °C. The suspension was then cooled to Ta = 30 °C. The product suspension was then filtered through a 1-liter glass funnel. The wet filter cake was first washed twice with 80 g of a water / acetone mixture and then with 62.5 g of acetone alone, allowing the washings to remain with the filter cake for at least 5 minutes. The washed filter cake was then separated by filtration and then dried first by blowing nitrogen gas over it, and then further dried in a vacuum chamber under reduced pressure at a temperature of 40 °C. The yield of etosibine was then determined to be 72.0 g.

[0269] The analytical data for the resulting product is shown in FIG.

[0270] The HPLC measurements, performed as described above, are shown in Figure 8 part 1.

[0271] LC-MS was performed as described above. Measurements (Figure 8, parts 2 and 3) showed 313.3 m / z: [M+H] + , 527.4 m / z: [2M-HPO4] + , and 625.4 m / z: [2M+H] + The presence of a peak was shown.

[0272] 1 The H NMR spectrum was measured at 400 MHz in DMSO-d+trifluoroacetic acid using a Bruker Avance 400 spectrometer. The spectrum is shown in Figure 8, part 4, and the observed peaks are summarized below.

[0273] JPEG2025531381000044.jpg42158

[0274] 13 The C NMR spectrum was measured at 125 MHz in DMSO-d + trifluoroacetic acid using a Bruker Avance 400 spectrometer. The spectrum is shown in Figure 8, part 5, and the observed peaks are summarized below.

[0275] The DSC measurements, performed as described above, are shown in Figure 8 part 6.

[0276] Example 2: Preparation of psilocybin according to the present invention The complete reaction scheme for obtaining psilocybin according to the methods of the present invention is shown in FIG.

[0277] Step 1b - Acetoxyindole glyoxylic acid dimethylamide Process Description: Acetoxyindole oxacetyl chloride (20 g) (obtained in Step 1 of Example 1, above) was dissolved in 2-MeTHF (261.8 g, 13.1 vol.). Dimethylamine 2m (63.8 g, 2.0 equiv.) in THF was charged to the reactor and cooled to -10 to -5°C. - Add the acid chloride solution to the amine solution while maintaining the internal temperature between Ti: -10 and 5°C. - Rinse the vessel used for the acid chloride solution with 2-MeTHF (27.2 g, 1.6 vol.) and add it to the reaction vessel. - Take a sample for IPC (stir the reaction mass at Ti:0°C until the IPC results are obtained) The reaction mass was concentrated under reduced pressure at 40°C to approximately 5 vol. -2-MeTHF (193 g, 10.8 vol) was added to the reaction mass - The reaction mass was concentrated again to about 5 vol. -2-MeTHF (177 g, 10 vol) was added to the reaction mass, thereby removing (at least to some extent) the THF and replacing it with 2-MeTHF (according to the inventors, the presence of THF had a detrimental effect on work-up). -0.5 m HCl (4 vol.) was added slowly to the reaction mixture while maintaining the internal temperature between Ti: 0 and 15°C. - If the reaction mass is a suspension: filter the reaction mass and wash the filter cake with 2-MeTHF / water 1:1 v / v (2.5 vol.); dry the filter cake under reduced pressure at Ta: 40°C to obtain the first crop of product (approximately 30% yield). - The combined mother liquor and washes are charged to the reactor and the phases are separated. - Extraction of the aqueous phase with ethyl acetate (5 vol.) (ethyl acetate shown in this case improved phase separation when compared to 2-Me-THF, used in Example 1 for ethosybin) - The combined organic phase was washed twice with NaHCO3 (5 vol.) The organic phase is charged into a reactor and concentrated under reduced pressure at Ta: 60°C to about 2.5 vol. -Cooling ramp: within 60 minutes, Ta: 0°C, and post-stirring at Ta: 0°C for 60 minutes - The suspension was filtered off and the filter cake was washed with ethyl acetate (1 vol.). - Dry the filter cake under reduced pressure at Ta: 40°C. - Second crop approximately 22%

[0278] The analytical data for the product so obtained is shown in FIG.

[0279] Step 2: Psilosin (4-hydroxy-dimethyltryptamine) Process Description: -CPME as reaction solvent -No charcoal treatment in post-processing The same process was used as for the synthesis of ethosine (4-HO-DET) in Example 1, except: -Yield: 70%

[0280] The analytical data for the resulting product is shown in FIG.

[0281] Step 3: Psilocybin Process Description: -The same process as for the synthesis of ethosybin (see Example 1 above) was used -Yield: 25%

[0282] The analytical data for the product so obtained is shown in FIG.

Claims

1. Formula (I): 【Chemical 1】 1. A method for preparing a compound of the formula wherein each R is independently C １－６ alkyl, preferably methyl or ethyl; wherein the method comprises reacting a compound of formula (Id): 【Chemistry 2】 The compound of (R'O) ２ POCl, wherein each R′ is independently selected from the group consisting of C １－６ Alkyl, —CH ２ -aryl and -CH ２ -heteroaryl, Here, the (R′O) of the compound of formula (Id) ２ The product of the reaction with POCl is further reacted with TMSBr to provide the compound of formula (I).

2. (R'O) ２ POCl is (MeO) ２ POCl, (EtO) ２ POCl, (tBuO) ２ POCl or (benzyl-O) ２ POCl, more preferably (EtO) ２ POCl or (tBuO) ２ POCl, even more preferably (EtO) ２ 2. The method of claim 1, wherein the compound is POCl.

3. Formula (I): 【Chemistry 3】 3. A method of preparing a compound of claim 1 or 2, comprising: wherein each R is independently C １－６ alkyl, preferably methyl or ethyl; wherein the method comprises reacting a compound of formula (Id): 【Chemistry 4】 (EtO) ２ reacting with POCl(DECP), wherein the product of the reaction of the compound of formula (Id) with DECP is further reacted with TMSBr to provide the compound of formula (I).

4. 4. The method of claim 1, wherein each R is independently methyl or ethyl.

5. 4. The method of claim 1, wherein each R is methyl.

6. 4. The method of claim 1, wherein each R is ethyl.

7. the w / w ratio of compound of formula (Id) and (DECP) is between 0.8 and 1.2, preferably between 1.0 and 1.2, more preferably between 1.10 and 1.15, even more preferably about 1.12, even more preferably 1.12, Preferably, the DECP is added dropwise over a period of between 10 and 20 minutes. A method according to claim 3 or any one of claims 4 to 6 insofar as it is dependent on claim 3.

8. 7. The process of claim 3 or 7, or any one of claims 4 to 6 insofar as it is dependent on claim 3, wherein the reaction of the compound of formula (Id) with DECP is carried out in acetonitrile.

9. 9. The process of claim 8, wherein the reaction of the compound of formula (Id) with DECP is carried out at a temperature between 50°C and 70°C, preferably between 55°C and 65°C, more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, and even more preferably at a temperature of 60°C.

10. 10. The process of claim 8 or 9, wherein the reaction of the compound of formula (Id) with DECP is carried out in the presence of a base, preferably wherein the base is N-ethyldiisopropylamine.

11. 11. The process of any one of claims 8 to 10, wherein the reaction of the compound of formula (Id) with DECP is carried out for a period of at least 150 minutes until at least 99% of the compound of formula (Id) has reacted.

12. Upon reaction of the compound of formula (Id) with DECP, the solvent is changed to toluene and aqueous NaOH solution is added thereto, followed by phase separation; Preferably, NaOH is added at a concentration of 0.5M to 1.0M, more preferably at a concentration of about 0.75M, even more preferably at a concentration of 0.75M.

12. The method of claim 3 or any one of claims 7 to 11, or any one of claims 4 to 6 insofar as it is dependent on claim 3.

13. Upon completion of the reaction of the compound of formula (Id) with DECP, the solvent is changed to CPME and HCl in CPME is added to the reaction mixture, which leads to precipitation of the crude product, preferably wherein the HCl in CPME is about a 3M solution, and / or said solution is added dropwise over a period of between 25 and 35 minutes, and / or said solution is added at a temperature between 15° C. and 20° C., preferably between 17° C. and 23° C., more preferably at a temperature of about 20° C., even more preferably at a temperature of 20° C., 13. The method of any one of claims 3 or 7 to 12, or any one of claims 4 to 6 insofar as it is dependent on claim 3.

14. Reaction of a compound of formula (Id) with DECP gives a compound of formula (Ie): 【Chemistry 5】 yielding a crude product of Preferably, the process of any one of claims 3 or 7 to 13, or any one of claims 4 to 6 insofar as it is dependent on claim 3, wherein the crude product precipitated from CPME upon addition of HCl comprises a compound of formula (Ie).

15. 15. The process of any one of claims 1 to 14, wherein the w / w ratio of TMSBr to compound of formula (Id) is between 1.5 and 2.5, more preferably between 1.8 and 2.4, even more preferably between 2.0 and 2.3, even more preferably about 2.0, and even more preferably 2.

07.

16. (R'O) of the compound of formula (Id) ２ 16. The process of any one of claims 1 to 15, wherein the product of the reaction with POCl, preferably with DECP, is reacted with TMSBr in acetonitrile.

17. 17. The process of any one of claims 1 to 16, wherein TMSBr is added at a temperature between 30°C and 50°C, preferably between 35°C and 45°C, more preferably between 37°C and 43°C, even more preferably at a temperature of about 40°C, even more preferably at a temperature of 40°C.

18. (R'O) of the compound of formula (Id) ２ 18. The process of any one of claims 1 to 17, wherein the product of the reaction with POCl, preferably with DECP, is reacted with TMSBr at a temperature between 50°C and 70°C, preferably between 55°C and 65°C, more preferably between 57°C and 63°C, even more preferably at a temperature of about 60°C, even more preferably at a temperature of 60°C.

19. Reaction with TMSBr results in the (R'O) of the compound of formula (Id). ２ 19. The process of any one of claims 1 to 18, carried out for at least 150 minutes until the product of the reaction with POCl, preferably with DECP, is at least 99% consumed.

20. 20. The process of any one of claims 1 to 19, wherein upon reaction with TMSBr, the solvent is changed to methanol.

21. 21. The process of any one of claims 1 to 20, wherein the obtained product of the reaction with TMSBr is subjected to a solvent change to water and the pH of the solution is set to a value ranging between pH=3.8 and pH=4.2, preferably through the addition of 1 M NaOH, preferably wherein the w / w ratio of 1 M NaOH solution to the original amount of compound of formula (Id) added is about 4.0, more preferably 4.0, and preferably wherein the final product of formula (I) precipitates from the aqueous solution at a pH between 3.8 and 4.2 and / or at a temperature below 20°C, preferably at a temperature of about 15°C, more preferably at a temperature of 15°C.

22. 22. The process of any one of claims 1 to 21, wherein the final product of formula (I) is reslurried upon treatment with water / acetone under reflux.

23. Formula (Ic): 【Chemistry 6】 23. The process of any one of claims 1 to 22, further comprising reducing the compound of formula (Id) to provide a compound of formula (Id).

24. In the step of reducing the compound of formula (Ic) to give the compound of formula (Id), LAH is used as a reducing agent; Preferably, wherein the step of reducing a compound of formula (Ic) to give a compound of formula (Id) is carried out in toluene, in dioxane or in CPME, preferably in toluene, 24. The method of claim 23 wherein preferably said step is carried out under reflux.

25. In the step of reducing the compound of formula (Ic) to give the compound of formula (Id), NaBH ４ 24. The method of claim 23, wherein is used as a reducing agent.

26. Formula (Ia): 【Chemistry 7】 The compound (COCl) ２ and then reacting the resulting product R ２ 26. The process of any one of claims 23 to 25, wherein the reaction is carried out with NH.

27. (COCl) of the compound of formula (Ia) ２ is carried out in CPME at a temperature between 0° C. and 10° C., and / or (COCl) of the compound of formula (Ia) ２ The reaction of formula (Ib): 【Chemistry 8】 resulting in a compound of wherein the compound of formula (Ib) is R ２ 27. The process of claim 26, wherein the compound is reacted with NH to provide a compound of formula (Ic).

28. Formula (I): 【Chemistry 9】 A method for obtaining a compound of the formula wherein each R is independently C １－６ alkyl, preferably methyl or ethyl; The method comprises reacting a compound of formula (Id): 【Chemistry 10】 (R'O) of the compound ２ reacting the product obtainable from the reaction with POCl with TMSBr to provide a compound of formula (I), wherein each R' is independently C １－６ Alkyl, —CH ２ -aryl and -CH ２ -heteroaryl.

29. Each R' is independently C １－６ Alkyl or -CH ２ -aryl, preferably each R' is independently C １－６ 29. The method of claim 28, wherein R' is alkyl, and more preferably both R' are ethyl.

30. (R'O) of the compound of formula (Id) ２ The product that can be obtained by reaction with POCl is of the formula: 【Chemistry 11】 or a salt thereof, preferably the HCl salt, wherein R and R' are as defined in claim 28 or 29.

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