Methods for the synthesis of plasmalogens and plasmalogen derivatives, and therapeutic uses thereof
A method for preparing plasmalogens and derivatives thereof represented by Formula B, wherein R1 and R2 are similar or different, derived from fatty acids; R3 is selected from hydrogen and small alkyl groups. The synthetic route involves production of novel cyclic plasmalogen precursors of Formula A and their conversion to plasmalogens and plasmalogen derivatives of Formula B. Also disclosed is the therapeutic use of plasmalogens and derivatives thereof as produced by the synthetic route of the present invention.
1. A process of preparing a compound represented by
wherein R 1 and R 2 are the same or different saturated, unsaturated, or polyunsaturated C 1 -C 28 hydrocarbon chains, and optionally derived from fatty acids; and R 3 is hydrogen or a C 1 -C 3 alkyl group, the process comprising:
a) coupling a solketel represented by Formula 1:
with an allyl halide to obtain a compound represented by Formula 2:
b) deprotecting the ketal present in the compound represented by Formula 2 to obtain a compound represented by Formula 3:
c) protecting the diol present in the compound represented by Formula 3 to obtain a compound represented by Formula (iv):
d) reacting a compound as represented by the formula X—R 1 with the compound represented by Formula (iv) to obtain a compound represented by Formula (v)
wherein R 1 is as defined above and X is a halogen,
e) deprotecting the ether groups present in the compound represented by Formula (v) to obtain a compound represented by Formula 6:
f) protecting the primary alcohol present in the compound represented by Formula 6 to yield a compound represented by Formula (vii):
g) esterifying a fatty acid as represented by R 2 —COOH to the compound represented by Formula (vii) to obtain a compound represented by Formula (viii):
wherein R 2 is as defined above,
h) deprotecting the ether present in the compound represented by Formula (viii) to obtain a compound represented by Formula 9
and
reacting POCl 3 with the compound represented by Formula 9, ethanolamine, and triethanolamine (TEA) to yield the compound represented by Formula A.
2. The process as claimed in claim 1 wherein R 1 , R 2 or both R 1 and R 2 are C 1 -C 28 alkyl chains comprising up to 6 double bonds.
3. The process as claimed in claim 1 wherein R 1 is a C 1 -C 20 alkyl group.
4. The process as claimed in claim 1 wherein R 2 is a C 2 -C 28 alkenyl group with 1 to 6 double bonds.
5. The process as claimed in claim 1 wherein R 3 is hydrogen.
6. The process as claimed in claim 1 wherein the allyl halide is allyl bromide.
7. The process as claimed in claim 1 wherein diol present in the compound represented by Formula 3 is protected with a tert-butyldimethylsilyl (TBS) group.
8. The process as claimed in claim 1 wherein X in XR 1 is Cl, Br, F or I.
9. The process as claimed in claim 1 wherein X in XR 1 is I.
10. The process as claimed in claim 1 wherein the primary alcohol present in the compound represented by Formula 6 is protected with a tert-butyldimethylsilyl (TBS) group.
11. The process as claimed in claim 1 wherein the compound as represented by X—R 1 in step (d) is iodotridecane.
12. The process as claimed in claim 1 wherein the fatty acid as represented by R 2 —COOH in step (g) is docosahexanoic acid (DHA).
13. The process as claimed in claim 11 wherein the iodotridecane is chemically synthesized.
14. The process as claimed in claim 12 wherein the DHA is chemically synthesized.
15. The process as claimed in claim 1 , wherein the coupling reaction of step (a) is carried out in the presence of NaH, tetrahydrofuran (THF) and allyl bromide.
16. The process as claimed in claim 15 , wherein the coupling reaction of step (a) is carried out at a temperature of between about 0° C. to about room temperature.
17. The process as claimed in claim 1 , wherein the deprotecting reaction of step (b) is conducted under acidic conditions in the presence of HCl.
18. The process as claimed in claim 17 , wherein the deprotecting reaction of step (b) is carried out at a temperature of about 80° C.
19. The process as claimed in claim 1 , wherein the protection reaction of step (c) comprises reacting the compound represented by Formula 3 with a tert-butyldimethylsilyl chloride (TBDMSC1) in the presence of dimethylformamide (DMF) and imidazole.
20. The process as claimed in claim 19 , wherein the protection reaction of step (c) is carried out at about room temperature.
21. The process as claimed in claim 1 , wherein the step (d) comprises reacting a haloalkane dissolved in tetrahydrofuran (THF) with the compound represented by Formula (iv) in the presence of THF and sec-BuLi.
22. The process as claimed in claim 21 , wherein the coupling reaction of step (d) is carried out at a temperature of between about −78° C. to about room temperature.
23. The process as claimed in claim 22 , wherein the haloalkane as represented by X—R 1 is iodotridecane.
24. The process as claimed in claim 23 , wherein the compound formed in step (d) is an α alkylated compound represented by Formula (v).
25. The process as claimed in claim 1 , wherein the deprotection reaction of step (e) is carried out in the presence of tetrahydrofuran (THF) and tetra-n-butylammonium fluoride (TBAF).
26. The process as claimed in claim 25 , wherein the deprotection reaction of step (e) is carried out at a temperature of between about 0° C. to about room temperature.
27. The process as claimed in claim 1 , wherein the protection reaction of step (f) comprises reacting tert-butyldimethylsilyl chloride (TBDMSC1) with the compound represented by Formula 6 in the presence of dichloromethane (DCM), triethanolamine (TEA) and 4-Dimethylaminopyridine (DMAP).
28. The process as claimed in claim 27 , wherein the protection reaction of step (f) is carried out at a temperature of between about 0° C. to about room temperature.
29. The process as claimed in claim 1 , wherein the esterification reaction of step (g) is carried out in the presence of dichloromethane (DCM), 1-ethyl-3-(3-dimethyllaminopropyl)carbodiimide hydrochloride (EDC.HCl) and 4-dimethylaminopyridine (DMAP).
30. The process as claimed in claim 29 , wherein the esterification reaction of step (g) is carried out at a temperature of between about 0° C. to about room temperature.
31. The process as claimed in claim 30 wherein the fatty acid as represented by R 2 —COOH is docosahexanoic acid (DHA).
32. The process as claimed in claim 1 , wherein the deprotection reaction of step (h) is carried out in the presence of tetrahydrofuran (THF), AcOH and tetra-n-butylammonium fluoride (TBAF).
33. The process as claimed in claim 32 , wherein the deprotection reaction of step (h) is carried out at a temperature of between about 0° C. to about room temperature.
34. The process as claimed in claim 1 , wherein the step (i) comprises:
a). reacting POCl 3 with the compound represented by Formula 9 dissolved in trichloroethylene in the presence of hexane and triethanolamine (TEA) to yield a crude material;
b). dissolving the crude material in tetrahydrofuran (THF) forming a reaction mixture; and
c). adding ethanolamine and TEA in THF to the reaction mixture to yield the compound represented by Formula A.
35. The process as claimed in claim 34 , wherein the step (i) is carried out at a temperature of between about 0° C. to about room temperature.
36. The process as claimed in claim 1 wherein the compound represented by Formula A which is obtained is:
37. A process of converting a compound represented by Formula A:
wherein R 1 and R 2 are the same or different saturated, unsaturated, or polyunsaturated C 1 -C 28 hydrocarbon chains, and optionally derived from fatty acids; and R 3 is hydrogen or a C 1 -C 3 alkyl group, the process comprising converting the compound represented by Formula A to a compound represented by Formula B:
the conversion process being carried out in the presence of tetrahydrofuran (THF) and H 2 O.
38. The process as claimed in claim 37 wherein the compound represented by Formula A is
39. The compound of Formula A:
wherein R 1 and R 2 are the same or different saturated, unsaturated, or polyunsaturated C 1 -C 28 hydrocarbon chains, and optionally derived from fatty acids; and R 3 is hydrogen or a C 1 -C 3 alkyl group, prepared by the process as claimed in claim 1 .