Preparation of psilocybin, different polymorphic forms, intermediates, formulations and their use
This invention relates to the large-scale production of psilocybin for use in medicine. More particularly, it relates to a method of obtaining high purity crystalline psilocybin, particularly, in the form of Polymorph A. It further relates to a method for the manufacture of psilocybin and intermediates in the production thereof and formulations containing psilocybin.
1. A method for manufacturing crystalline Polymorph A of psilocybin from psilocin at a scale greater than 100 g, comprising:
(i) reacting psilocin with tetrabenzylpyrophosphate to form benzyl 3-[2-(benzyldimethylazaniumyl)ethyl]-1H-indol-4-yl phosphate;
(ii) reacting the benzyl 3-[2-(benzyldimethylazaniumyl)ethyl]-1H-indol-4-yl phosphate with hydrogen in the presence of a catalyst to form psilocybin; and
(iii) crystallizing the psilocybin from water;
wherein the step (iii) further comprises drying the crystallized psilocybin to provide crystalline Polymorph A of psilocybin characterized by X-ray powder diffraction (XRPD) peaks at 11.5±0.1, 12.0±0.1, 14.5±0.1, 17.5±0.1 and 19.7±0.1 °2θ, and wherein the crystallized psilocybin has a chemical purity of greater than 97% and no single impurity of greater than 1% as determined by HPLC analysis.
2. The method of claim 1 , wherein the psilocin is manufactured by a method comprising:
(1) reacting 1H-indol-4-yl acetate with oxalyl chloride and dimethylamine to form 3-([(dimethylcarbamoyl)carbonyl])-1H-indol-4-yl acetate; and
(2) reacting the 3-([(dimethylcarbamoyl)carbonyl)-1H-indol-4-yl acetate with lithium aluminum hydride to form psilocin.
3. The method of claim 1 , wherein step (i) further comprises adding sodium hexamethyldisilazide (NaHMDS).
4. The method of claim 1 , wherein tetrahydrofuran (THF) is used as a solvent in step (i).
5. The method of claim 1 , wherein the step (i) reaction is initiated at a temperature below −50° C.
6. The method of claim 2 , wherein the step (1) reaction comprises:
(a) reacting 1H-indol-4-yl acetate with oxalyl chloride to form 3-(2-chloro-2-oxoacetyl)-1H-indol-4-yl acetate; and
(b) reacting the 3-(2-chloro-2-oxoacetyl)-1H-indol-4-yl acetate with dimethylamine to form 3-([(dimethylcarbamoyl)carbonyl])-1H-indol-4-yl acetate.
7. The method of claim 6 , wherein the step (a) reaction is conducted in tert-butyl methyl ether (TBME) and THF.
8. The method of claim 6 , wherein the step (a) reaction is conducted at a temperature of about 30° C.-40° C.
9. The method of claim 6 , wherein the dimethylamine is used in excess in the step (b) reaction.
10. The method of claim 9 , wherein the step (b) reaction further comprises separating dimethylamine salts from the reaction mixture resulting from reacting the 3-(2-chloro-2-oxoacetyl)-1H-indol-4-yl acetate with the dimethylamine through a purification step, wherein the purification step comprises forming a slurry comprising the reaction mixture and filtering the reaction mixture.
11. The method of claim 10 , wherein the purification step comprises:
slurrying the reaction mixture resulting from step (b) with water, isopropyl alcohol (IPA), or a mixture thereof;
filtering the slurry to provide isolated 3-([(dimethylcarbamoyl)carbonyl])-1H-indol-4-yl acetate; and
drying the isolated 3-([(dimethylcarbamoyl)carbonyl])-1H-indol-4-yl acetate.
12. The method of claim 2 , wherein the in step (24) reaction is conducted in THF.
13. The method of claim 12 , wherein a solution of the lithium aluminum hydride is added to the 3-([(dimethylcarbamoyl)carbonyl])-1H-indol-4-yl acetate.
14. The method of claim 12 , wherein the step (24) reaction further comprises quenching with acetone.
15. The method of claim 12 , wherein the step (24) reaction further comprises quenching with citric acid.
16. The method of claim 12 , wherein the step (2) reaction further comprises filtering a psilocin solution through silica and washed washing the silica with in THF.
17. The method of claim 16 , wherein the psilocin solution is evaporated to dryness, and the resulting solid is slurried in a mixture of isopropyl acetate and TBME, filtered, washed with in TBME, and dried to provide psilocin.
18. The method of claim 6 , wherein the reaction mixture from step (b) is filtered, washed with heptane, and dried to provide the 3-([(dimethylcarbamoyl)carbonyl])-1H-indol-4-yl acetate.
19. The method of claim 1 , wherein the crystallizing step (iii) comprises combining the psilocybin with about 10-20 volumes of water, heating with agitation to a temperature of at least 70° C. to provide a solution, polish filtering the solution, seeding the solution at a temperature of about 70° C., cooling the solution to a temperature of about 5° C. over a period of more than 2 hours, and isolating the crystallized psilocybin.
20. The method of claim 19 , wherein the psilocybin is combined with about 10 volumes of water.
21. The method of claim 19 , wherein the heating with agitation is at a temperature from 75° C. to 80° C.
22. The method of claim 19 , wherein the temperature during the cooling is decreased at a rate of about 10° C. an hour.
23. The method of claim 19 , wherein the seeding comprises adding crystalline Hydrate A of psilocybin to the solution, wherein the crystalline Hydrate A of psilocybin is characterized by X-ray powder diffraction (XRPD) peaks at 8.9±0.1, 13.8±0.1, 19.4±0.1, 23.1±0.1 and 23.5±0.1 °2θ.
24. The method of claim 19 , wherein the isolated crystallized psilocybin is washed several times with water.
25. The method of claim 19 , wherein the crystallized psilocybin has a chemical purity of greater than 99% as determined by HPLC analysis.
26. The method of claim 1 , wherein the catalyst is a palladium on carbon (Pd/C) catalyst.