SYNTHESIS OF MDMA OR ITS OPTICALLY ACTIVE (R)- OR (S)-MDMA ISOMERS

Abstract

Provided herein is a process for the preparation of 3,4-methylenedioxymethamphetamine, (R)-3,4-methylenedioxymethamphetamine and (S)-3,4-methylenedioxymethamphetamine.

Claims

1-24. (canceled)

25. A process for the preparation of 3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the process comprising: i) preparing an organometallic reagent from a compound of Formula (I): ##STR00056## wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; ii) reacting the organometallic reagent of step i) with a compound of Formula (II): ##STR00057## wherein R.sub.3 is alkyl; and iii) converting the product of step ii) to 3,4-methylenedioxymethamphetamine.

26. The process of claim 25, wherein the compound of Formula (I) is a compound of Formula (Ia): ##STR00058##

27. The process of claim 26, wherein X is bromine.

28. The process of claim 25, wherein R.sub.3 is tert-butyl.

29. The process of claim 25, wherein step i) comprises reacting the compound of Formula (I) with magnesium.

30. The process of claim 26, wherein step i) comprises reacting the compound of Formula (Ia) with magnesium.

31. The process of claim 25, wherein the step i) further comprises adding a copper (I) salt to the reaction mixture.

32. The process of claim 31, wherein the copper (I) salt is CuI.

33. The process of claim 25, wherein the product of step ii) is a compound of Formula (IIIb): ##STR00059##

34. The process of claim 25, wherein the product of step ii) is a compound of Formula (IIIc): ##STR00060##

35. The process of claim 25, wherein the step iii) comprises reacting a group of Formula (IVb) with a reducing agent to provide a group of Formula (Vb), or a pharmaceutically acceptable salt thereof: ##STR00061##

36. The process of claim 35, wherein the reducing agent is lithium aluminum hydride.

37. 3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process of claim 25.

38. A process for the preparation of (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the process comprising: i) preparing an organometallic reagent from a compound of Formula (I): ##STR00062## wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; ii) reacting the organometallic reagent of step i) with a compound of Formula (IIa): ##STR00063## wherein R.sub.3 is alkyl; and iii) converting the product of step ii) to (R)-3,4-methylenedioxymethamphetamine.

39. The process of claim 38, wherein the compound of Formula (I) is a compound of Formula (Ia): ##STR00064##

40. The process of claim 39, wherein X is bromine.

41. The process of claim 38, wherein R.sub.3 is tert-butyl.

42. The process of claim 38, wherein step i) comprises reacting the compound of Formula (I) with magnesium.

43. The process of claim 39, wherein step i) comprises reacting the compound of Formula (Ia) with magnesium.

44. The process of claim 38, wherein the step i) further comprises adding a copper (I) salt to the reaction mixture.

45. The process of claim 44, wherein the copper (I) salt is CuI.

46. The process of claim 38, wherein the product of step ii) is a compound of Formula (IIIb): ##STR00065##

47. The process of claim 38, wherein the product of step ii) is a compound of Formula (IIIb′): ##STR00066##

48. The process of claim 38, wherein the step iii) comprises reacting a group of Formula (IVa) with a reducing agent to provide a group of Formula (Va), or a pharmaceutically acceptable salt thereof: ##STR00067##

49. The process of claim 48, wherein the reducing agent is lithium aluminum hydride.

50. The process of claim 38, wherein the process provides (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of a least 99.5%.

51. (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process of claim 38.

52. A process for the preparation of (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the process comprising: i) preparing an organometallic reagent from a compound of Formula (I): ##STR00068## wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; ii) reacting the organometallic reagent of step i) with a compound of Formula (II): ##STR00069## wherein R.sub.3 is alkyl; and iii) converting the product of step ii) to (S)-3,4-methylenedioxymethamphetamine.

53. The process of claim 52, wherein the compound of Formula (I) is a compound of Formula (Ia): ##STR00070##

54. The process of claim 53, wherein X is bromine.

55. The process of claim 52, wherein R.sub.3 is tert-butyl.

56. The process of claim 52, wherein step i) comprises reacting the compound of Formula (I) with magnesium.

57. The process of claim 53, wherein step i) comprises reacting the compound of Formula (Ia) with magnesium.

58. The process of claim 52, wherein the step i) further comprises adding a copper (I) salt to the reaction mixture.

59. The process of claim 58, wherein the copper (I) salt is CuI.

60. The process of claim 52, wherein the product of step ii) is a compound of Formula (III): ##STR00071##

61. The process of claim 52, wherein the product of step ii) is a compound of Formula (IIIa): ##STR00072##

62. The process of claim 52, wherein the step iii) comprises reacting a group of Formula (IV) with a reducing agent to provide a group of Formula (V), or a pharmaceutically acceptable salt thereof: ##STR00073##

63. The process of claim 62, wherein the reducing agent is lithium aluminum hydride.

64. The process of claim 52, wherein the process provides (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of a least 99.5%.

65. (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process of claim 52.

Description

DETAILED DESCRIPTION

[0028] Throughout this disclosure, various patents, patent applications and publications are referenced. The disclosures of these patents, patent applications and publications in their entireties are incorporated into this disclosure by reference for all purposes in order to more fully describe the state of the art as known to those skilled therein as of the date of this disclosure. This disclosure will govern in the instance that there is any inconsistency between the patents, patent applications and publications cited and this disclosure.

Definitions

[0029] For convenience, certain terms employed in the specification, examples and claims are collected here. Unless defined otherwise, all technical and scientific terms used in this disclosure have the same meanings as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0030] The term “about” when immediately preceding a numerical value means a range (e.g., plus or minus 10% of that value). For example, “about 50” can mean 45 to 55, “about 25,000” can mean 22,500 to 27,500, etc., unless the context of the disclosure indicates otherwise, or is inconsistent with such an interpretation. For example in a list of numerical values such as “about 49, about 50, about 55, . . . ”, “about 50” means a range extending to less than half the interval(s) between the preceding and subsequent values, e.g., more than 49.5 to less than 50.5. Furthermore, the phrases “less than about” a value or “greater than about” a value should be understood in view of the definition of the term “about” provided herein. Similarly, the term “about” when preceding a series of numerical values or a range of values (e.g., “about 10, 20, 30” or “about 10-30”) refers, respectively to all values in the series, or the endpoints of the range.

[0031] The term “pharmaceutically acceptable salts” includes both acid and base addition salts. Pharmaceutically acceptable salts include those obtained by reacting the active compound functioning as a base, with an inorganic or organic acid to form a salt, for example, salts of hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, camphorsulfonic acid, oxalic acid, maleic acid, succinic acid, citric acid, formic acid, hydrobromic acid, benzoic acid, tartaric acid, fumaric acid, salicylic acid, mandelic acid, carbonic acid, etc. The acids that may be used to prepare pharmaceutically acceptable acid addition salts of such basic compounds are those that form non-toxic acid addition salts, i.e., salts containing pharmaceutically acceptable anions, including but not limited to malate, oxalate, chloride, bromide, iodide, nitrate, acetate, tartrate, oleate, fumarate, formate, benzoate, glutamate, methanesulfonate, benzenesulfonate, and p-toluenesulfonate salts. Base addition salts include but are not limited to, ethylenediamine, N-methyl-glucamine, lysine, arginine, ornithine, choline, N,N′-dibenzylethylenediamine, chloroprocaine, diethanolamine, procaine, N-benzylphenethylamine, diethylamine, piperazine, tris-(hydroxymethyl)-aminomethane, tetramethylammonium hydroxide, triethylamine, dibenzylamine, ephenamine, dehydroabietylamine, N-ethylpiperidine, benzylamine, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, ethylamine, basic amino acids, e.g., lysine and arginine dicyclohexylamine and the like. Examples of metal salts include lithium, sodium, potassium, magnesium, calcium salts and the like. Examples of ammonium and alkylated ammonium salts include ammonium, methylammonium, dimethylammonium, trimethylammonium, ethylammonium, hydroxyethylammonium, diethylammonium, butylammonium, tetramethylammonium salts and the like. Examples of organic bases include lysine, arginine, guanidine, diethanolamine, choline and the like. Those skilled in the art will further recognize that acid addition salts may be prepared by reaction of the compounds with the appropriate inorganic or organic acid via any of a number of known methods.

[0032] When a range of values is listed, it is intended to encompass each value and sub-range within the range. For example, “C.sub.1-C.sub.6 alkyl” is intended to encompass C.sub.1, C.sub.2, C.sub.3, C.sub.4, C.sub.5, C.sub.6, C.sub.1-6, C.sub.1-5, C.sub.1-4, C.sub.1-3, C.sub.1-2, C.sub.2-6, C.sub.2-5, C.sub.2-4, C.sub.2-3, C.sub.3-6, C.sub.3-5, C.sub.3-4, C.sub.4-6, C.sub.4-5, and C.sub.5-6 alkyl.

[0033] “Alkyl” or “alkyl group” refers to a fully saturated, straight or branched hydrocarbon chain having from one to twelve carbon atoms, and which is attached to the rest of the molecule by a single bond. Alkyls comprising any number of carbon atoms from 1 to 12 are included. An alkyl comprising up to 12 carbon atoms is a C.sub.1-C.sub.12 alkyl, an alkyl comprising up to 10 carbon atoms is a C.sub.1-C.sub.10 alkyl, an alkyl comprising up to 6 carbon atoms is a C.sub.1-C.sub.6 alkyl and an alkyl comprising up to 5 carbon atoms is a C.sub.1-C.sub.5 alkyl. A C.sub.1-C.sub.5 alkyl includes C.sub.5 alkyls, C.sub.4 alkyls, C.sub.3 alkyls, C.sub.2 alkyls and C.sub.1 alkyl (i.e., methyl). A C.sub.1-C.sub.6 alkyl includes all moieties described above for C.sub.1-C.sub.5 alkyls but also includes C.sub.6 alkyls. A C.sub.1-C.sub.10 alkyl includes all moieties described above for C.sub.1-C.sub.5 alkyls and C.sub.1-C.sub.6 alkyls, but also includes C.sub.7, C.sub.5, C.sub.9 and C.sub.10 alkyls. Similarly, a C.sub.1-C.sub.12alkyl includes all the foregoing moieties, but also includes C.sub.11 and C.sub.12 alkyls. Non-limiting examples of C.sub.1-C.sub.12 alkyl include methyl, ethyl, n-propyl, i-propyl, sec-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-pentyl, t-amyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl.

[0034] Unless stated otherwise specifically in the specification, an alkyl group can be optionally substituted.

[0035] “Heterocyclyl,” “heterocyclic ring” or “heterocycle” refers to a stable saturated, unsaturated, or aromatic 3- to 20-membered ring which consists of two to nineteen carbon atoms and from one to six heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur, and which is attached to the rest of the molecule by a single bond. Heterocyclyl or heterocyclic rings include heteroaryls, heterocyclylalkyls, heterocyclylalkenyls, and hetercyclylalkynyls. Unless stated otherwise specifically in the specification, the heterocyclyl can be a monocyclic, bicyclic, tricyclic or tetracyclic ring system, which can include fused, bridged, or spirocyclic ring systems; and the nitrogen, carbon or sulfur atoms in the heterocyclyl can be optionally oxidized; the nitrogen atom can be optionally quaternized; and the heterocyclyl can be partially or fully saturated. Examples of such heterocyclyl include, but are not limited to, dioxolanyl, thienyl[1,3]dithianyl, decahydroisoquinolyl, imidazolinyl, imidazolidinyl, isothiazolidinyl, isoxazolidinyl, morpholinyl, octahydroindolyl, octahydroisoindolyl, 2-oxopiperazinyl, 2-oxopiperidinyl, 2-oxopyrrolidinyl, oxazolidinyl, piperidinyl, piperazinyl, 4-piperidonyl, pyrrolidinyl, pyrazolidinyl, quinuclidinyl, thiazolidinyl, tetrahydrofuryl, trithianyl, tetrahydropyranyl, thiomorpholinyl, thiamorpholinyl, 1-oxo-thiomorpholinyl, and 1,1-dioxo-thiomorpholinyl. Unless stated otherwise specifically in the specification, a heterocyclyl group can be optionally substituted.

[0036] The term “substituted” used herein means any of the groups described herein (e.g., alkyl, heterocyclyl, and/or heteroaryl) wherein at least one hydrogen atom is replaced by a bond to a non-hydrogen atoms such as, but not limited to: a halogen atom such as F, Cl, Br, and I; an oxygen atom in groups such as hydroxyl groups, alkoxy groups, and ester groups; a sulfur atom in groups such as thiol groups, thioalkyl groups, sulfone groups, sulfonyl groups, and sulfoxide groups; a nitrogen atom in groups such as amines, amides, alkylamines, dialkylamines, arylamines, alkylarylamines, diarylamines, N-oxides, imides, and enamines; a silicon atom in groups such as trialkylsilyl groups, dialkylarylsilyl groups, alkyldiarylsilyl groups, and triarylsilyl groups; and other heteroatoms in various other groups. “Substituted” also means any of the above groups in which one or more hydrogen atoms are replaced by a higher-order bond (e.g., a double- or triple-bond) to a heteroatom such as oxygen in oxo, carbonyl, carboxyl, and ester groups; and nitrogen in groups such as imines, oximes, hydrazones, and nitriles. For example, “substituted” includes any of the above groups in which one or more hydrogen atoms are replaced with —NR.sub.gR.sub.h, —NR.sub.gC(O)R.sub.h, —NR.sub.gC(═O)NR.sub.gR.sub.h, —NR.sub.gC(O)OR.sub.h, —NR.sub.gSO.sub.2R.sub.h, —OC(═O)NR.sub.gR.sub.h, —OR.sub.g, —SR.sub.g, —SOR.sub.g, —SO.sub.2R.sub.g, —OSO.sub.2R.sub.g, —SO.sub.2OR.sub.g, ═NSO.sub.2R.sub.g, and —SO.sub.2NR.sub.gR.sub.h. “Substituted” also means any of the above groups in which one or more hydrogen atoms are replaced with —C(═O)R.sub.g, —C(═)OR.sub.g, —C(═O)NR.sub.gR.sub.h, —CH.sub.2SO.sub.2R.sub.g, —CH.sub.2SO.sub.2NR.sub.gR.sub.h. In the foregoing, R.sub.g and R.sub.h are the same or different and independently hydrogen, alkyl, alkenyl, alkynyl, alkoxy, alkylamino, thioalkyl, aryl, aralkyl, cycloalkyl, cycloalkenyl, cycloalkylalkyl, haloalkyl, haloalkenyl, haloalkynyl, heterocyclyl, N-heterocyclyl, heterocyclylalkyl, heteroaryl, N-heteroaryl and/or heteroarylalkyl. “Substituted” further means any of the above groups in which one or more hydrogen atoms are replaced by a bond to an amino, cyano, hydroxyl, imino, nitro, oxo, thioxo, halo, alkyl, alkenyl, alkynyl, alkoxy, alkylamino, thioalkyl, aryl, aralkyl, cycloalkyl, cycloalkenyl, cycloalkylalkyl, haloalkyl, haloalkenyl, haloalkynyl, heterocyclyl, N-heterocyclyl, heterocyclylalkyl, heteroaryl, N-heteroaryl and/or heteroarylalkyl group. In addition, each of the foregoing substituents can also be optionally substituted with one or more of the above substituents.

[0037] As used herein, the symbol “” (hereinafter can be referred to as “a point of attachment bond”) denotes a bond that is a point of attachment between two chemical entities, one of which is depicted as being attached to the point of attachment bond and the other of which is not depicted as being attached to the point of attachment bond. For example,

##STR00007##

indicates that the chemical entity “XY” is bonded to another chemical entity via the point of attachment bond. Furthermore, the specific point of attachment to the non-depicted chemical entity can be specified by inference. For example, the compound CH.sub.3—R.sup.3X, wherein R.sup.3X is H or

##STR00008##

infers that when R.sup.3X is “XY”, the point of attachment bond is the same bond as the bond by which R.sup.3X is depicted as being bonded to CH.sub.3.

Methods

[0038] In an aspect, the methods described herein provide high purity, 3,4-methylenedioxymethamphetamine (MDMA) in a high yielding 3-step process, starting from readily available and inexpensive starting materials (e.g., 5-bromobenzo[d][1,3]dioxole (3) and alaninol). In an aspect, the disclosure provides a process for preparation of racemic 3,4-methylenedioxymethamphetamine or a pharmaceutically acceptable salt thereof.

[0039] In an aspect, the disclosure provides a process for the preparation of (R)- or (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof.

[0040] In embodiments, the methods described herein provide high purity, enantiopure (R) or (S) 3,4-methylenedioxymethamphetamine (MDMA) in a high yielding 3-step process, starting from readily available and inexpensive starting materials (e.g., 5-bromobenzo[d][1,3]dioxole (3) and D-alaninol (1)). By starting with a chiral pool starting materials, such as (D-alaniol (1)), enantiopure (R)-MDMA can be prepared without the need for expensive and wasteful chiral ligands, chiral auxiliaries, or diastereomeric salt resolutions, and provide MDMA with higher optical purity (e.g., 99.5% ee or greater, or 99.9% ee) than other routes, which give lower selectivity and require enantiomeric enrichment by purification/crystallization. By installing a Boc group as both a nitrogen protecting group and a masked methyl equivalent, the need for a methylation reaction is avoided, which often uses GTI alkylating reagents like methyl iodide or dimethylsulfate. It also cleanly installs the single methyl group and avoids the potential of over-alkylation and provides enantioenriched (R)-MDMA in a streamlined process, providing significant improvements on prior syntheses which are more complex and/or require synthetic longer routes see e.g., ACS Chem Neurosci. 2018 October 17; 9(10): 2408-2427, FIG. 3. The unnatural enantiomer of (1) (L-alaninol) can be used by the same process to prepare (S)-MDMA.

Preparation of 3,4-methylenedioxymethamphetamine

[0041] In an aspect, the disclosure provides a process for the preparation of 3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the process comprising: [0042] i) preparing an organometallic reagent from a compound of Formula (I):

##STR00009## [0043] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; [0044] ii) reacting the organometallic reagent of step i) with a compound of Formula (IIb):

##STR00010## [0045] wherein R.sub.3 is alkyl; and [0046] iii) converting the product of step ii) to 3,4-methylenedioxymethamphetamine.

[0047] In embodiments, the compound of Formula (IIb) is a racemate.

[0048] In embodiments of the processes provided herein for the preparation of 3,4-methylenedioxymethamphetamine, the process comprises i) preparing an organometallic reagent from a compound of Formula (I):

##STR00011##

[0049] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle.

[0050] In some embodiments of any one of the processes for the preparation of 3,4-methylenedioxymethamphetamine described herein, R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle.

[0051] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, the compound of Formula (I) is a compound of Formula (Ia):

##STR00012##

[0052] In embodiments of the compounds of Formula (I) or (Ia), X is Cl, Br, or I. In some embodiments, X is Cl. In some embodiments, X is Br. In some embodiments, X is I.

[0053] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium. In some embodiments, step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium in the presence of a solvent, for example an ether solvent such as tetrahydrofuran, diethyl ether, or 2-methyltetrahydrofuran. In some embodiments, the solvent is heated e.g., to 50-70° C., 60-70° C., or 60-66° C. In some embodiments, the solvent is heated to reflux. In some embodiments, the solvent is THF and the THF is heated to reflux.

[0054] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, step i) further comprises adding a copper (I) salt (e.g., CuI, CuCl, or CuBr.SMe.sub.2) to the reaction mixture. In some embodiments, after formation of the Grignard species, the solution is cooled, and copper iodide (CuI) is added. In some embodiments, the solution is cooled for example, to a temperature between 0° C. and −78° C. and copper iodide (CuI) is added. In some embodiments, the organometallic reagent selectively opens the aziridine at the less hindered carbon, retaining the stereochemistry of the nitrogen stereocenter to give carbamate protected methylenedioxyamphetamine.

[0055] In embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, step ii) comprises reacting the organometallic reagent of step i) with a compound of Formula (IIb):

##STR00013##

[0056] wherein R.sub.3 is alkyl. In some embodiments, step ii) comprises adding a compound of Formula (IIb) to the cooled solution of organometallic reagent from step i).

[0057] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, R.sub.3 is C.sub.1-6 alkyl. In some embodiments, R.sub.3 is C.sub.1-4 alkyl. In some embodiments, R.sub.3 is tert-butyl.

[0058] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, the product of step ii) is a compound of Formula (IIIb):

##STR00014##

[0059] wherein R.sub.3 is defined herein.

[0060] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, the product of step ii) is a compound of Formula (IIIc):

##STR00015##

[0061] wherein R.sub.1, R.sub.2, and R.sub.3 are defined herein.

[0062] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, step iii) comprises reacting a group of Formula (IVb) with a reducing agent to provide a group of Formula (Vb), or a pharmaceutically acceptable salt thereof:

##STR00016##

[0063] In some embodiments, step iii) comprises reacting a group of Formula (IVb) with a reducing agent to provide a group of Formula (Vb), or a pharmaceutically acceptable salt thereof in the presence of a solvent, for example an ether solvent such as tetrahydrofuran, diethyl ether, 2-methyltetrahydrofuran. In some embodiments, the solvent is heated. In some embodiments, the solvent is refluxing THF.

[0064] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, the reducing agent in step iii) is a hydride reducing agent. In some embodiments, the reducing agent in step iii) is lithium aluminum hydride.

[0065] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, the process provides 3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof in racemic form.

[0066] In some embodiments of the process for the preparation of 3,4-methylenedioxymethamphetamine, the 3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof has a chemical purity of greater than about 95%, greater than about 98%, or greater than about 99% by HPLC.

[0067] In some embodiments, the present disclosure provides 3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process described herein.

Preparation of (S)-3,4-methylenedioxymethamphetamine

[0068] In an aspect, the disclosure provides a process for the preparation of (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the process comprising: [0069] i) preparing an organometallic reagent from a compound of Formula (I):

##STR00017## [0070] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; ii) reacting the organometallic reagent of step i) with a compound of Formula (II):

##STR00018## [0071] wherein R.sub.3 is alkyl; and [0072] iii) converting the product of step ii) to (S)-3,4-methylenedioxymethamphetamine.

[0073] In embodiments of the processes provided herein for the preparation of (S)-3,4-methylenedioxymethamphetamine, the process comprises i) preparing an organometallic reagent from a compound of Formula (I):

##STR00019##

[0074] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle.

[0075] In some embodiments of any one of the processes for the preparation of (S)-3,4-methylenedioxymethamphetamine described herein, R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle.

[0076] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, the compound of Formula (I) is a compound of Formula (Ia):

##STR00020##

[0077] In embodiments of the compounds of Formula (I) or (Ia), X is Cl, Br, or I. In some embodiments, X is C.sub.1. In some embodiments, X is Br. In some embodiments, X is I.

[0078] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium. In some embodiments, step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium in the presence of a solvent, for example an ether solvent such as tetrahydrofuran, diethyl ether, 2-methyltetrahydrofuran. In some embodiments, the solvent is heated e.g., to 50-70° C., or 60-70° C., or 60-66° C. In some embodiments, the solvent is heated to reflux. In some embodiments, the solvent is THF and the THF is heated to reflux.

[0079] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, step i) further comprises adding a copper (I) salt (e.g., CuI, CuCl, CuBr.SMe.sub.2) to the reaction mixture. In some embodiments, after formation of the Grignard species, the solution is cooled, and copper iodide (CuI) is added. In some embodiments, the solution is cooled for example, to a temperature between 0° C. and −78° C. and copper iodide (CuI) is added. In some embodiments, the organometallic reagent selectively opens the aziridine at the less hindered carbon, retaining the stereochemistry of the nitrogen stereocenter to give carbamate protected methylenedioxyaphetamine.

[0080] In embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, step ii) comprises reacting the organometallic reagent of step i) with a compound of Formula (II):

##STR00021##

[0081] wherein R.sub.3 is alkyl. In some embodiments, step ii) comprises adding a compound of Formula (II) to the cooled solution of organometallic reagent from step i).

[0082] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, R.sub.3 is C.sub.1-6 alkyl. In some embodiments, R.sub.3 is C.sub.1-4 alkyl. R.sub.3 is tert-butyl.

[0083] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, the product of step ii) is a compound of Formula (III):

##STR00022##

[0084] wherein R.sub.3 is defined herein.

[0085] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, the product of step ii) is a compound of Formula (IIIa):

##STR00023##

[0086] wherein R.sub.1, R.sub.2, and R.sub.3 are defined herein.

[0087] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, step iii) comprises reacting a group of Formula (IV) with a reducing agent to provide a group of Formula (V), or a pharmaceutically acceptable salt thereof:

##STR00024##

[0088] In some embodiments, step iii) comprises reacting a group of Formula (IV) with a reducing agent to provide a group of Formula (V), or a pharmaceutically acceptable salt thereof in the presence of a solvent, for example an ether solvent such as tetrahydrofuran, diethyl ether, 2-methyltetrahydrofuran. In some embodiments, the solvent is heated. In some embodiments, the solvent is refluxing THF.

[0089] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, the reducing agent in step iii) is a hydride reducing agent. In some embodiments, the reducing agent in step iii) is lithium aluminum hydride.

[0090] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, the process provides (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof in substantially optically pure form. In some embodiments, the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, the process provides (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of about or at least about 55% ee, about or at least about 60% ee, about or at least about 65% ee, about or at least about 70% ee, about or at 75% ee, about or at least about 80% ee, about or at least about 85% ee, about or at least about 90% ee, about or at least about 91%, about or at least about 92%, about or at least about 93% ee, about or at least about 94% ee, about or at least about 95% ee, about or at least about 96% ee, about or at least about 97% ee, about or at least about 98% ee, about or at least about 99% ee, about or at least about 99.5% ee, or about or at least about 99.9% ee, including all subranges and values therebetween. In some embodiments, the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, the process provides (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of a least 99.5%. In some embodiments, ee is measured by chiral HPLC.

[0091] In some embodiments of the process for the preparation of (S)-3,4-methylenedioxymethamphetamine, the (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof has a chemical purity of greater than about 95%, greater than about 98%, or greater than about 99% by HPLC.

[0092] In some embodiments, the present disclosure provides (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process described herein.

Preparation of (R)-3,4-methylenedioxymethamphetamine

[0093] In an aspect, the disclosure provides a process or the preparation of (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the method comprising: [0094] i) preparing an organometallic reagent from a compound of Formula (I):

##STR00025## [0095] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; [0096] ii) reacting the organometallic reagent of step i) with a compound of Formula (IIa):

##STR00026## [0097] wherein R.sub.3 is alkyl; and [0098] iii) converting the product of step ii) to (R)-3,4-methylenedioxymethamphetamine.

[0099] In embodiments of the processes provided herein for the preparation of (R)-3,4-methylenedioxymethamphetamine, the process comprises i) preparing an organometallic reagent from a compound of Formula (I):

##STR00027##

[0100] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle.

[0101] In some embodiments of any one of the processes for the preparation of (R)-3,4-methylenedioxymethamphetamine described herein, R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle.

[0102] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, the compound of Formula (I) is a compound of Formula (Ia):

##STR00028##

[0103] In embodiments of the compounds of Formula (I) or (Ia), X is C.sub.1, Br, or I. In some embodiments, X is C.sub.1. In some embodiments, X is Br. In some embodiments, X is I.

[0104] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium. In some embodiments, step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium in the presence of a solvent, for example an ether solvent such as tetrahydrofuran, diethyl ether, 2-methyltetrahydrofuran. In some embodiments, the solvent is heated e.g., to 50-70° C. In some embodiments, the solvent is THF and the THF is heated to reflux.

[0105] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, step i) further comprises adding a copper (I) salt (e.g., CuI, CuCl, CuBr.SMe.sub.2) to the reaction mixture. In some embodiments, after formation of the Grignard species, the solution is cooled, and copper iodide (CuI) is added. In some embodiments, the solution is cooled for example, to a temperature between 0° C. and −78° C. and copper iodide (CuI) is added. In some embodiments, the organometallic reagent selectively opens the aziridine at the less hindered carbon, retaining the stereochemistry of the nitrogen stereocenter to give carbamate protected methylenedioxyamphetamine.

[0106] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, step ii) comprises reacting the organometallic reagent of step i) with a compound of Formula (IIa):

##STR00029##

[0107] wherein R.sub.3 is alkyl. In some embodiments, step ii) comprises adding a compound of Formula (IIa) to the cooled solution of organometallic reagent from step i).

[0108] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, R.sub.3 is C.sub.1-6 alkyl. In some embodiments, R.sub.3 is C.sub.1-4 alkyl. R.sub.3 is tert-butyl.

[0109] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, the product of step ii) is a compound of Formula (IIIb):

##STR00030##

[0110] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, the product of step ii) is a compound of Formula (IIIb′):

##STR00031##

[0111] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, step iii) comprises reacting a group of Formula (IVa) with a reducing agent to provide a group of Formula (Va), or a pharmaceutically acceptable salt thereof:

##STR00032##

[0112] In some embodiments, step iii) comprises reacting a group of Formula (IV) with a reducing agent to provide a group of Formula (V), or a pharmaceutically acceptable salt thereof in the presence of a solvent, for example an ether solvent such as tetrahydrofuran, diethyl ether, 2-methyltetrahydrofuran.

[0113] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, the reducing agent in step iii) is a hydride reducing agent. In some embodiments, the reducing agent in step iii) is lithium aluminum hydride.

[0114] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, the process provides (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof in substantially optically pure form. In some embodiments, the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, the process provides (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of about or at least about 55% ee, about or at least about 60% ee, about or at least about 65% ee, about or at least about 70% ee, about or at 75% ee, about or at least about 80% ee, about or at least about 85% ee, about or at least about 90% ee, about or at least about 91%, about or at least about 92%, about or at least about 93% ee, about or at least about 94% ee, about or at least about 95% ee, about or at least about 96% ee, about or at least about 97% ee, about or at least about 98% ee, about or at least about 99% ee, about or at least about 99.5% ee, or about or at least about 99.9% ee, including all subranges and values therebetween. In some embodiments, the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, the process provides (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of a least 99.5%. In some embodiments, ee is measured by chiral HPLC.

[0115] In some embodiments of the process for the preparation of (R)-3,4-methylenedioxymethamphetamine, the (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof has a chemical purity of greater than about 95%, greater than about 98%, or greater than about 99% by HPLC.

[0116] In some embodiments, the present disclosure provides (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process described herein.

NUMBERED EMBODIMENTS

[0117] 1. A process for the preparation of (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the process comprising: [0118] i) preparing an organometallic reagent from a compound of Formula (I):

##STR00033## [0119] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; [0120] ii) reacting the organometallic reagent of step i) with a compound of Formula (II):

##STR00034## [0121] wherein R.sub.3 is alkyl; and [0122] iii) converting the product of step ii) to (S)-3,4-methylenedioxymethamphetamine. [0123] 2. The process of embodiment 1, wherein the compound of Formula (I) is a compound of Formula (Ia):

##STR00035## [0124] 3. The process of embodiment 2, wherein X is bromine. [0125] 4. The process of any one of embodiments 1-3, wherein R.sub.3 is tert-butyl. [0126] 5. The process of any one of embodiments 1-4, wherein step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium. [0127] 6. The process of embodiment 5, wherein the step i) further comprises adding a copper (I) salt (e.g., CuI) to the reaction mixture. [0128] 7. The process of any one of embodiments 1-6, wherein the product of step ii) is a compound of Formula (III):

##STR00036## [0129] 8. The process of any one of embodiments 1-6, wherein the product of step ii) is a compound of Formula (IIIa):

##STR00037## [0130] 9. The process of any one of embodiments 1-8, wherein the step iii) comprises reacting a group of Formula (IV) with a reducing agent to provide a group of Formula (V), or a pharmaceutically acceptable salt thereof:

##STR00038## [0131] 10. The process of embodiment 9, wherein the reducing agent is lithium aluminum hydride. [0132] 11. The process of any one of embodiments 1-10, wherein the process provides (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of a least 99.5%. [0133] 12. (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process of any one of embodiments 1-10. [0134] 13. A process for the preparation of (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the process comprising: [0135] i) preparing an organometallic reagent from a compound of Formula (I):

##STR00039## [0136] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; [0137] ii) reacting the organometallic reagent of step i) with a compound of Formula (IIa):

##STR00040## [0138] wherein R.sub.3 is alkyl; and [0139] iii) converting the product of step ii) to (R)-3,4-methylenedioxymethamphetamine. [0140] 14. The process of embodiment 13, wherein the compound of Formula (I) is a compound of Formula (Ia):

##STR00041## [0141] 15. The process of any one of embodiments 13-14, wherein X is bromine. [0142] 16. The process of any one of embodiments 13-15, wherein R.sub.3 is tert-butyl. [0143] 17. The process of any one of embodiments 13-16, wherein step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium. [0144] 18. The process of embodiment 17, wherein the step i) further comprises adding a copper (I) salt (e.g., CuI) to the reaction mixture. [0145] 19. The process of any one of embodiments 13-18, wherein the product of step ii) is a compound of Formula (IIIb):

##STR00042## [0146] 20. The process of any one of embodiments 13-18, wherein the product of step ii) is a compound of Formula (IIIb′):

##STR00043## [0147] 21. The process of any one of embodiments 13-20, wherein the step iii) comprises reacting a group of Formula (IVa) with a reducing agent to provide a group of Formula (Va), or a pharmaceutically acceptable salt thereof:

##STR00044## [0148] 22. The process of embodiment 21, wherein the reducing agent is lithium aluminum hydride. [0149] 23. The process of any one of embodiments 13-22, wherein the process provides (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of a least 99.5%. [0150] 24. (R)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process of any one of embodiments 13-23. [0151] 25. A process for the preparation of 3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt thereof, the process comprising: [0152] i) preparing an organometallic reagent from a compound of Formula (I):

##STR00045## [0153] wherein X is a halogen; R.sub.1 is a protecting group, R.sub.2 is a protecting group or R.sub.1 and R.sub.2 together with the atoms to which they are attached form a 5-membered heterocycle; [0154] ii) reacting the organometallic reagent of step i) with a compound of Formula (II):

##STR00046## [0155] wherein R.sub.3 is alkyl; and [0156] iii) converting the product of step ii) to 3,4-methylenedioxymethamphetamine. [0157] 26. The process of embodiment 25, wherein the compound of Formula (I) is a compound of Formula (Ia):

##STR00047## [0158] 27. The process of embodiment 26, wherein X is bromine. [0159] 28. The process of any one of embodiments 25-27, wherein R.sub.3 is tert-butyl. [0160] 29. The process of any one of embodiments 25-28, wherein step i) comprises reacting the compound of Formula (I) or Formula (Ia) with magnesium. [0161] 30. The process of embodiment 29, wherein the step i) further comprises adding a copper (I) salt (e.g., CuI) to the reaction mixture. [0162] 31. The process of any one of embodiments 25-30, wherein the product of step ii) is a compound of Formula (III):

##STR00048## [0163] 32. The process of any one of embodiments 25-30, wherein the product of step ii) is a compound of Formula (IIIc):

##STR00049## [0164] 33. The process of any one of embodiments 1-8, wherein the step iii) comprises reacting a group of Formula (IVb) with a reducing agent to provide a group of Formula (Vb), or a pharmaceutically acceptable salt thereof:

##STR00050## [0165] 34. The process of embodiment 33, wherein the reducing agent is lithium aluminum hydride. [0166] 35. The process of any one of embodiments 25-34, wherein the process provides (S)-3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt in an enantiomeric excess of a least 99.5%. [0167] 36. 3,4-methylenedioxymethamphetamine, or a pharmaceutically acceptable salt prepared by a process of any one of embodiments 25-35.

EXAMPLES

[0168] Compounds of the present disclosure can be synthesized using the following exemplary methods or other methods that are known to those skilled in the art.

[0169] General reaction conditions are provided, and reaction products can be purified by known methods including silica gel chromatography using various organic solvents such as hexane, dichloromethane, ethyl acetate, methanol and the like or preparative reverse phase high pressure liquid chromatography.

[0170] Preparation of compounds can involve the protection and deprotection of various chemical groups. The need for protection and deprotection, and the selection of appropriate protecting groups can be readily determined by one skilled in the art. The chemistry of protecting groups can be found, for example, in Greene and Wuts, Protective Groups in Organic Synthesis, 44th. Ed., Wiley & Sons, 2006, as well as in Jerry March, Advanced Organic Chemistry, 4.sup.th edition, John Wiley & Sons, publisher, New York, 1992 which are incorporated herein by reference in their entirety.

General Synthesis of (R)-3,4-methylenedioxymethamphetamine (MDMA)

[0171] (R)-3,4-methylenedioxymethamphetamine (MDMA) can be synthesized according to Scheme 1, below.

##STR00051##

Step 1: Synthesis of tert-butyl (R)-2-methylaziridine-1-carboxylate (2)

[0172] ##STR00052##

[0173] D-alaninol (1) is protected with di-tert-butyl decarbonate (Boc anhydride) in organic solvent (e.g., halogenated solvent such as dichloromethane (DCM), ether solvent such as tetrahydrofuran (THF) or methyl-tetrahydrofuran (Me-THF)) e.g. at <about 10° C. to ambient temperature, over a few hours. To the protected D-alaninol is then added 4-toluenesulfonyl chloride (TsCl), followed by potassium hydroxide (KOH), which installs the tosyl group on the alcohol, and deprotonates the carbamate nitrogen, facilitating aziridine formation. The enantiopure aziridine (2) is then isolated and purified, e.g., by chromatography on SiO.sub.2 or by distillation.

Step 2: Synthesis of tert-butyl (R)-(1-(benzo[d][1,3]dioxol-5-yl)propan-2-yl)carbamate (4)

[0174] ##STR00053##

[0175] In a second step, the Grignard reagent of 5-bromobenzo[d][1,3]dioxole (3) is generated by treatment of 5-bromobenzo[d][1,3]dioxole (3) with magnesium, optionally in the presence of 12, in organic solvent (e.g., ether solvent such as tetrahydrofuran (THF) or methyl-tetrahydrofuran (Me-THF)) and the mixture heated, e.g., between about 40° C. to about 70° C., or about 50° C. to about 60° C. After formation of the Grignard species, the solution is cooled (e.g., to about 0° C. or less) and Copper (I) salt e.g., CuI or CuBr.SMe.sub.2 is added. The previously isolated Boc-aziridine (2) is then added to the cooled solution of cuprate and stirred until the reaction is complete. The reaction is then quenched with an aqueous solution e.g., with NH.sub.4Cl and the organic phase extracted with organic solvent and purified by chromatography on SiO.sub.2, or by crystallization.

Step 3: Synthesis of (R)-3,4-methylenedioxymethamphetamine (MDMA)

[0176] ##STR00054##

[0177] The Boc-MDA (4) is then dissolved in organic solvent (e.g., in an ether solvent such as tetrahydrofuran, (THF) or 2-methyltetrahydrofuran (Me-THF)), cooled and treated with lithium aluminum hydride (LiAlH.sub.4) to reduce the carbamate to the methylamine. In some embodiments, the solution is heated (e.g., to reflux) to reduce the carbamate to the methylamine. The reaction is quenched and worked-up via the Fieser method with water, NaOH and methyl tert-butyl ether.

[0178] The crude MDMA free base can then be isolated e.g., by crystallization, or converted into the HCl salt using a solution of HCl.

[0179] (S)-3,4-methylenedioxymethamphetamine (MDMA) can be synthesized according to Scheme 1 employing L-alaninol instead of D-alaninol.

Example 1: Synthesis of (R)-3,4-methylenedioxymethamphetamine (MDMA)

[0180] (R)-3,4-methylenedioxymethamphetamine (MDMA) can be synthesized according to the Scheme below.

##STR00055##

Step 1, Route 1: Synthesis of tert-butyl (R)-2-methylaziridine-1-carboxylate

[0181] To a 300 mL jacketed reactor was charged D-alaninol (20 g, 266.3 mmol, 1.00 eq) and DCM (100 mL) then cooled to 0-5° C. under N.sub.2. A solution of Boc.sub.2O (64.2 g, 292.9 mmol, 1.1 eq) in DCM (100 mL) was added over 40 minutes maintaining an internal temperature of <12° C. After the addition was complete the reaction was warmed to 20° C. After 3.5 hours no D-alaninol was detected by TLC. The reaction was diluted with water (50 mL), then the organic layer was washed with sat. NaCl (2×50 mL), dried over MgSO.sub.4, filtered and concentrated under reduced pressure to afford crude Boc-D-alaninol (62.2 g). The crude product was charged to the 300 mL reactor as a solution in THF (200 mL) at 20° C. Solid TsCl (66.2 g, 1.3 eq) was charged resulting in a 10° C. endotherm. Solid powdered KOH (60.1 g, 4.0 eq) was added in portions—the initial KOH charge resulted in a strong exotherm (>20° C.), requiring setting the TCU to 0° C. Subsequent charges only saw <5° C. exotherms. As the mixture cooled to <30° C. the reaction was held at 20° C. After 20 minutes the mixture became very thick and a further 100 mL of THF was added to aid mixing. After stirring for 21 hours the mixture was filtered and the filter cake washed with MTBE. The filtrate was concentrated under reduced pressure to afford crude compound 2 (52.1 g). Chromatographic purification on silica (600 g), eluting with 0-60% EtOAc/heptanes afforded compound 2 (13.1 g, 31%) as a light yellow oil.

Step 1, Route 2: Synthesis of tert-butyl (R)-2-methylaziridine-1-carboxylate

[0182] To a 250 mL RBF was charged D-alaninol (EMP-2, 5.0 g, 66.6 mmol, 1.00 eq) and THF (33 mL) then cooled to 0-5° C. under N.sub.2. A solution of Boc.sub.2O (14.9 g, 67.9 mmol, 1.02 eq) in THF (7.5 mL) was added over 50 minutes maintaining an internal temperature of <10° C. After the addition was complete the reaction was warmed to 15° C. After 16 hours no D-alaninol was detected by TLC. A solution of TsCl (17.8 g, 1.4 eq) in THF (10 mL) was added at 15° C., resulting in a 3° C. endotherm, followed by a THF (2.5 mL) rinse. Solid powdered KOH (18.3 g, 4.9 eq) was added resulting in a strong exotherm (>35° C.), requiring external cooling. The reaction mixture became white slurry. After stirring for 22 hours the mixture was diluted with MTBE (25 mL, 5 vol), filtered and the filter cake washed with MTBE. The filtrate was passed through a silica plug (30 g), eluting with MTBE to afford compound 2 (7.37 g, 57%,).

Step 2: Synthesis of tert-butyl (R)-(1-(benzo[d][1,3]dioxol-5-yl)propan-2-yl)carbamate (4)

[0183] To a 100 mL RBF was charged Mg (0.155 g, 6.36 mmol, 2.00 eq), I2 (one crystal) and THF (3 mL) at room temperature under N.sub.2. Bromide 3 (0.1 g) was added to the mixture and heated to 50° C. at which time the iodine color disappeared and the internal temperature rose to 56° C. Bromide 3 (1.20 g, total added 1.30 g, 6.46 mmol, 2.0 eq) was added, via syringe, to the mixture dropwise maintaining an internal temperature of 45-55° C. over 10 minutes. After addition was complete the syringe was rinsed with THF (0.5 mL) and the rinse charged to the reaction at 49° C. After stirring for 1.5 hours the batch was a clear amber color with an internal temperature of 19.6° C. THF (2.0 mL) was added.

[0184] The flask was cooled to 0.8° C. using an ice/water bath then solid CuBr.SMe.sub.2 (0.131 g, 0.636 mmol, 0.20 eq) was charged in one portion. An exotherm to 6° C. was observed. After cooling to 0.5° C. a solution of R-Boc-aziridine 2 (87.8 wt %, 0.57 g, 3.18 mmol, 1.00 eq) in THF (1.5 mL) was added over 20 minutes, while maintaining an internal temperature <6° C. After stirring for 4 hours TLC analysis (5:1 heptanes/EA) of the brown slurry showed complete reaction. After a further 20 minutes the reaction was quenched with dropwise addition sat. NH.sub.4Cl (5.0 mL), while maintaining an internal temperature <18° C. (3 minutes). After stirring for 12 minutes at room temperature the biphasic mixture was diluted with EtOAc (3 mL). The layers were separated, and the aqueous layer was extracted with EtOAc (2×3 mL). The combined organic layers dried over Na.sub.2SO.sub.4 (2.5 g), filtered and concentrated under reduced pressure. Chromatographic purification in silica, eluting with 0-15% EtOAc/heptanes afforded compound 4 (0.77 g, 87%,) as a solid.

Step 3: Synthesis of (R)-3,4-methylenedioxymethamphetamine (MDMA)

[0185] To a 5-neck 2 L jacketed reactor was charged compound 4 (78.3 g, 280.6 mmols, 1.0 eq) and THF (1.4 L, 18 vol). The solution is heated to 55 to 60° C. and a solution of lithium aluminum hydride (LAH, 2 M in THF, 430 mL, 842 mmols, 3.0 eq) is slowly added over 1.5 hours, maintaining an internal temperature of 55 to 65° C. After 1 hour, IPC analysis by HPLC showed 0.6% compound 4 remaining. After an additional 2 hours, IPC analysis showed 0.5% compound 4 remaining. The batch was cooled to 0 to 5° C. and 32 mL of water was slowly charged over ˜80 minutes, keeping the reaction temperature below 15° C. 15% NaOH (32 mL) was then added over 8 minutes, followed by water (96 mL). The thick slurry was warmed to ambient temperature and stirred overnight. The slurry was filtered, and the filter cake washed with methyl tert-butyl ether (2×2 vol). The filtrate was concentrated under reduced pressure to afford crude (R)-MDMA (54.0 g) which was diluted with MeOH (118 mL) and MTBE (1.3 L) at ambient temperature under nitrogen. To the solution was added 3M HCl in MeOH (140 mL, 1.5 eq), resulting in the formation of a white slurry. The slurry was stirred for 30 minutes and filtered, and the filter cake was washed with MTBE (3×200 mL).

[0186] The cake was dried under reduced pressure to afford (R)-MDMA-HCl (55.2 g, 85%) with an HPLC purity of 99.5% area by HPLC.