Process for the preparation of (2R,3S)-2-(hydroxymethyl)-5-methoxytetrahydrofuran-3-OL and acetylated derivatives thereof, free of pyranose compounds
A method of preparing a ribofuranose derivative essentially free of pyranose compounds includes a step of contacting a solution of MDR containing MDRP as an impurity in a solvent including methanol and/or tetrahydrofuran with at least one alkali metal periodate under conditions sufficient to oxidize at least a portion of the MDRP. MDR containing at most 5 wt % of MDRP based on the total weight of MDR and MDRP may be produced.
1. A method of preparing a ribofuranose derivative essentially free of pyranose compounds, comprising a step of contacting a solution of MDR containing MDRP as an impurity in a solvent comprising methanol with at least one alkali metal periodate under conditions sufficient to oxidize at least a portion of the MDRP, wherein the solution has a pH in a range from 2.5 to 5.5 during the contacting.
2. The method of claim 1 , wherein after said contacting the amount of MDRP present is at most 5 wt % based on the total weight of MDR and MDRP.
3. The method of claim 1 , further comprising subsequently isolating purified MDR from the solution, wherein the isolated MDR contains at most 5 wt % of MDRP based on the total weight of MDR and MDRP.
4. The method of claim 1 , wherein the solution does not comprise any added buffer.
5. The method of claim 1 , wherein the solution does not comprise any added phosphate.
6. The method of claim 1 , wherein at least 50 wt % of all alkali metals in the solution comes from the at least one alkali metal periodate.
7. The method of claim 1 , wherein methanol constitutes at least 70 wt % of the solvent.
8. The method of claim 1 , wherein water constitutes from 0.1 wt % to 30 wt % of the solvent.
9. The method of claim 1 further comprising, prior to said contacting, preparing the solution of the MDR containing the MDRP by a method comprising contacting 2DR with methanol in the presence of an acid under conditions sufficient to convert substantially all of the 2DR to MDR containing the MDRP as said impurity.
10. The method of claim 1 , wherein the at least one alkali metal periodate comprises sodium periodate.
11. The method of claim 10 , wherein the sodium periodate is prepared by a process that includes adding aqueous sodium periodate to methanol that may optionally also contain water and/or the MDR containing the MDRP, under conditions sufficient to cause at least a portion of the sodium periodate to precipitate as a particulate solid.
12. A method of preparing a ribofuranose derivative essentially free of pyranose compounds, comprising a step of contacting a solution of MDR containing MDRP as an impurity in a solvent comprising tetrahydrofuran with at least one alkali metal periodate under conditions sufficient to oxidize at least a portion of the MDRP, wherein the solution has a pH in a range from 2.5 to 5.5 during the contacting.
13. The method of claim 1 , further comprising converting the MDR to (4S,5R)-5-(acetoxymethyl)tetrahydrofuran-2,4-diyl diacetate.
14. The method of claim 13 , comprising the steps of converting the MDR to [(2R, 3S)-3-acetoxy-5-methoxy-tetrahydrofuran-2-yl]methyl acetate and converting the [(2R,3S)-3-acetoxy-5-methoxy-tetrahydrofuran-2-yl]methyl acetate to said (4S,5R)-5-(acetoxymethyl)tetrahydrofuran-2,4-diyl diacetate.
15. The method of claim 14 , wherein the step of converting the [(2R,3S)-3-acetoxy-5-methoxy-tetrahydrofuran-2-yl]methyl acetate to said (4S,5R)-5-(acetoxymethyl)tetrahydrofuran-2,4-diyl diacetate comprises reaction of the [(2R,3S)-3-acetoxy-5-methoxy-tetrahydrofuran-2-yl]methyl acetate with acetic anhydride in acetic acid in the presence of a catalytic amount of sulfuric acid;
wherein the method further comprises after the reaction a step of adding sodium acetate to the reaction mixture in an amount sufficient to neutralize the sulfuric acid.
16. The method of claim 12 , further comprising converting the MDR to (4S,5R)-5-(acetoxymethyl)tetrahydrofuran-2,4-diyl diacetate.
17. The method of claim 16 , comprising the steps of converting the MDR to [(2R, 3S)-3-acetoxy-5-methoxy-tetrahydrofuran-2-yl]methyl acetate and converting the [(2R,3S)-3-acetoxy-5-methoxy-tetrahydrofuran-2-yl]methyl acetate to said (4S,5R)-5-(acetoxymethyl)tetrahydrofuran-2,4-diyl diacetate.
18. The method of claim 17 , wherein the step of converting the [(2R,3S)-3-acetoxy-5-methoxy-tetrahydrofuran-2-yl]methyl acetate to said (4S,5R)-5-(acetoxymethyl)tetrahydrofuran-2,4-diyl diacetate comprises reaction of the [(2R,3S)-3-acetoxy-5-methoxy-tetrahydrofuran-2-yl]methyl acetate with acetic anhydride in acetic acid in the presence of a catalytic amount of sulfuric acid;
wherein the method further comprises after the reaction a step of adding sodium acetate to the reaction mixture in an amount sufficient to neutralize the sulfuric acid.