Purification of bis-quaternary pyridinium oximes
Purification of bis-quaternary pyridinium oximes (BQPO) which may serve as organophosphorus nerve agent antidotes.
1. A method of improving the relative purity of bis-quaternary pyridinium oximes comprising:
(a) supplying a bis-quaternary pyridinium oxime of the following structure:
where R 1 , R 2 , R 3 and R 4 may be independently selected from the group consisting of hydrogen, alkyl, —CH═NOH or —CONH 2 and X − comprises Cl − , Br − , I − or − OSO 2 CH 3 ;
(b) treating said bis-quaternary pyridinium oxime with an alkyl phosphate of the formula Z 2 PO4, where Z is an alkyl group and forming a bis-quaternary pyridinium oxime, of the following structure:
(c) treating said bis-quaternary pyridinium oxime with an acid HY, wherein Y comprises Cl, Br, I or OSO 2 CH 3 ;
(d) recovering a bis-quaternary pyridinium oxime of improved relative purity of the following structure:
wherein Y − comprises Cl − , Br − , I − or − OSO 2 CH 3 .
2. The method of claim 1 wherein said bis-quaternary pyridinium oxime comprises HLö-7 dimethylsulfate.
3. The method of claim 1 wherein said bis-quaternary pyridinium oxime comprises HI-6 dimethylsulfate.
4. The method of claim 1 wherein said bis-quaternary pyridinium oxime comprises obidoxime dimethylsulfate.
5. The method of claim 1 wherein said bis-quaternary pyridinium oxime comprises HLö-7 bischloride.
6. The method of claim 1 wherein the number of carbon atoms in the alky phosphate is at least eight carbon atoms.
7. The method of claim 1 wherein said alkyl phosphate comprises bis-(2-ethylhexyl) phosphate.
8. The method of claim 1 wherein said bis-quaternary pyridinium oxime salt recovered in step (d) is recovered at a yield of greater than or equal to 80.0%.
9. The method of claim 1 wherein said bis-quaternary pyridinium oxime introduced in step (a) indicates a HPLC purity of less than 70.0%.
10. The method of claim 1 wherein said bis-quaternary pyridinium oxime recovered in step (d) indicates a HPLC purity of greater than 70.0%.
11. The method of claim 1 wherein said bis-quaternary pyridinium oxime recovered in step (d) undergoes solvent recrystallization and indicates a HPLC purity of greater than 90.0%.
12. The method of claim 11 wherein said bis-quaternary pyridinium oxime salt with a HPLC purity of greater than 90.0% is combined with one or more excipients and forming a pharmaceutical composition.
13. A method of improving the relative purity of bis-quaternary pyridinium oximes comprising:
a. supplying a bis-quaternary pyridinium oxime of the following structure:
where R 1 , R 2 , R 3 and R 4 may be independently selected from the group consisting of hydrogen, alkyl, —CH═NOH or —CONH 2 and X − comprises Br − , I − or − OSO 2 CH 3 ;
b. subjecting said bis-quaternary pyridinium oxime to an ion exchange reaction to convert X − to Cl − and providing a bis-quaternary pyridinium oxime of the following structure:
and
c. placing said bis-quaternary pyridinium oxime in an organic alcohol containing a metal salt and eluting through a chromatography column containing silica as the stationary phase and recovering said bis-quaternary pyridinium oxime produced in step (b) in relatively purified form.
14. The method of claim 13 wherein said organic alcohol in step (c) comprises methanol, ethanol, isopropanol, or tert-butanol.
15. The method of claim 13 wherein said metal salt in step (c) comprises calcium chloride sodium bromide or sodium iodide.
16. The method of claim 13 wherein said calcium chloride, sodium bromide, or sodium iodide is present at a concentration of 0.1 M to 0.5 M.
17. The method of claim 13 wherein said metal salt in step (c) comprises calcium chloride at 0.1M to 0.3M.
18. The method of claim 13 wherein said bis-quaternary pyridinium oxime introduced in step (a) indicates a HPLC purity of less than 70.0%.
19. The method of claim 13 wherein said bis-quaternary pyridinium oxime recovered in step (c) indicates a HPLC purity of greater than 70.0%.
20. The method of claim 13 wherein said bis-quaternary pyridinium oxime recovered in step (c) undergoes solvent recrystallization and indicates a HPLC purity of greater than 90.0%.
21. The method of claim 20 wherein said purified bis-quaternary pyridinium oxime salt with a HPLC purity of greater than 90.0% is combined with one or more excipients and forming a pharmaceutical composition.
22. A method of improving the relative purity of bis-quaternary pyridinium oximes comprising:
a. supplying a bis-quaternary pyridinium oxime of the following structure:
where R 1 , R 2 , R 3 and R 4 may be independently selected from the group consisting of hydrogen, alkyl, —CH═NOH or —CONH 2 ;
b. placing said bis-quaternary pyridinium oxime in an organic alcohol containing a metal salt and eluting through a chromatography column containing silica as the stationery phase and recovering said bis-quaternary pyridinium oxime produced in step (b) in relatively purified form.
23. The method of claim 22 wherein said organic alcohol in step (b) comprises methanol, ethanol, isopropanol or tert-butanol.
24. The method of claim 22 wherein said metal salt in step (b) comprises calcium chloride sodium bromide or sodium iodide.
25. The method of claim 22 wherein said calcium chloride, sodium bromide, or sodium iodide is present at a concentration of 0.1 M to 0.5 M.
26. The method of claim 22 wherein said metal salt in step (c) comprises calcium chloride at 0.1M to 0.3M.
27. The method of claim 22 wherein said bis-quaternary pyridinium oxime introduced in step (a) indicates a HPLC purity of less than 70.0%.
28. The method of claim 22 wherein said bis-quaternary pyridinium oxime recovered in step (b) indicates a HPLC purity of greater than 70.0%.
29. The method of claim 22 wherein said bis-quaternary pyridinium oxime recovered in step (b) undergoes solvent recrystallization and indicates a HPLC purity of greater than 90.0%.
30. The method of claim 29 wherein said bis-quaternary pyridinium oxime salt with a HPLC purity of greater than 90.0% is combined with one or more excipients and forming a pharmaceutical composition.