Methods for the synthesis of deuterated acrylate salts
A method for synthesizing a deuterated acrylate of the Formula (1), the method comprising: (i) deuterating a propiolate compound of Formula (2) to a methyne-deuterated propiolate compound of Formula (3) in the presence of a base and D 2 O: and (ii) reductively deuterating the methyne-deuterated propiolate compound of Formula (3) in a reaction solvent in the presence of deuterium gas and a palladium-containing catalyst to afford the deuterated acrylate of the Formula (1). The resulting deuterated acrylate compounds, derivatives thereof, and polymers derived therefrom are also described.
1. A method for synthesizing a deuterated acrylate of the formula
wherein Z is an alkali metal atom or H,
the method comprising:
(i) deuterating a compound of Formula (2) to a compound of Formula (3) by the following reaction pathway conducted in the presence of a base and D 2 O:
and
(ii) reductively deuterating the compound of Formula (3) in a reaction solvent in the presence of deuterium gas and a palladium-containing catalyst to afford the deuterated acrylate of the Formula (1).
2. The method of claim 1 , wherein Z is an alkali metal.
3. The method of claim 1 , wherein the base in step (i) is non-protic.
4. The method of claim 3 , wherein the non-protic base is a carbonate salt.
5. The method of claim 1 , wherein step (i) is practiced by removal of D 2 O and its proton-exchanged forms after an initial reaction to convert the compound of Formula (2) to the compound of Formula (3), followed by addition of fresh D 2 O and further deuterating the compound of Formula (2) to the compound of Formula (3).
6. The method of claim 1 , wherein the reaction solvent in step (ii) is a deuterated alcohol in which at least the protic hydrogen of the deuterated alcohol is replaced with a deuterium atom.
7. The method of claim 6 , wherein the deuterated alcohol is deuterated methanol.
8. The method of claim 1 , wherein the deuterium gas in step (ii) is used in an excess of 5-15% in an inert gas.
9. The method of claim 1 , wherein the deuterium gas in step (ii) is used in an excess of 7-10% in an inert gas.
10. The method of claim 1 , wherein the palladium-containing catalyst is a Lindlar catalyst comprised of Pd(0) on calcium carbonate or barium sulfate along with deactivators comprised of lead additive and organic inhibitor.
11. The method of claim 10 , wherein said organic inhibitor is selected from nitrogen-containing and sulfur-containing organic compounds.
12. The method of claim 11 , wherein said organic inhibitor is selected from quinoline and 2,2′-(ethylenedithio)diethanol.
13. The method of claim 10 , wherein said Lindlar catalyst is included in an amount of 5-25 wt % by weight of the compound of Formula (3).
14. The method of claim 10 , wherein said quinoline is included in an amount of up to 50% by weight of the catalyst.
15. The method of claim 10 , wherein the Pd(0) is in an amount of about 4-6 wt % by weight of the Lindlar catalyst.
16. The method of claim 10 , wherein the lead additive is used in an amount of 2-5 wt % by weight of the Lindlar catalyst.
17. The method of claim 1 , wherein step (ii) is conducted in the presence of a radical polymerization inhibitor.
18. The method of claim 17 , wherein said radical polymerization inhibitor is included in an amount of up to 2 wt % by weight of the compound of Formula (3).
19. The method of claim 17 , wherein said radical polymerization inhibitor is hydroquinone or 2,6-di-tert-butyl-4-methylphenol.
20. The method of claim 1 , wherein Z is an alkali metal atom, and the method further comprises protonating the compound of Formula (1) to make Z a hydrogen or deuterium atom.
21. The method of claim 1 , wherein the compound of Formula (1) is obtained in a yield of at least 80%.
22. The method of claim 1 , wherein the compound of Formula (1) is obtained in a yield of at least 85%.
23. The method of claim 1 , wherein the compound of Formula (1) has a level of deuteration of at least 90 atom % D.
24. The method of claim 1 , wherein the compound of Formula (1) has a level of deuteration of at least 95 atom % D.
25. The method of claim 1 , wherein side reaction byproducts resulting from step (ii), including unreacted compound of Formula (3) and sodium propionate, are present in an amount of no more than 10 mole % with respect to total product resulting from the reaction of step (ii).
26. The method of claim 1 , wherein side reaction byproducts resulting from step (ii), including unreacted compound of Formula (3) and sodium propionate, are present in an amount of no more than 7 mole % with respect to total product resulting from the reaction of step (ii).