Halogenated cyclic diesters, related polymers, and methods for their preparation and use

1. A method for making trifluoromethyl-functionalized poly(lactic acid), the method comprising:

preparing a brown oil containing trifluoromethyl-functionalized lactide monomer by adding, to trifluorolactic acid dissolved in acetonitrile, triethylamine followed by 2-bromopropionyl bromide; and

adding the brown oil to a mixture of sodium hydride and acetonitrile.

2. The method of claim 1 wherein the trifluorolactic acid dissolved in acetonitrile is prepared by:

under nitrogen gas flow, adding the trifluorolactic acid to a dry round bottom flask containing dry acetonitrile and triethylamine to prepare a mixture of trifluorolactic acid, triethylamine, and acetonitrile; and

stirring and cooling the mixture of trifluorolactic acid, triethylamine, and acetonitrile in an ice bath.

3. The method of claim 2 wherein the 2-bromopropionyl bromide is added by:

preparing a solution of 2-bromopropionyl bromide in acetonitrile; and

dropwise adding the solution of 2-bromopropionyl bromide in acetonitrile solution to the trifluorolactic acid, triethylamine, and acetonitrile mixture to produce a first reaction mixture.

4. The method of claim 3 further comprising:

stirring the first reaction mixture at room temperature for 3 hours;

filtering a white precipitate from the first reaction mixture and concentrating the filtrate under reduced pressure to produce trifluoromethyl-functionalized-lactide-monomer product;

dissolving the trifluoromethyl-functionalized-lactide-monomer product in ethyl acetate;

filtering the trifluoromethyl-functionalized-lactide-monomer product in ethyl acetate to remove any remaining salts; and

removing ethyl acetate by rotary evaporation to produce a brown oil.

5. The method of claim 1 wherein the mixture of sodium hydride and acetonitrile is prepared by stirring sodium hydride in dry acetonitrile in an ice bath under nitrogen gas flow.

6. The method of claim 5 further comprising:

adding the brown oil to dry acetonitrile.

7. The method of claim 6 further comprising:

dropwise adding the mixture of blown oil and acetonitrile to the mixture of sodium hydride and acetonitrile to produce a second reaction mixture.

8. The method of claim 7 further comprising: stirring the second reaction mixture at room temperature for 1 hour.

9. The method of claim 8 further comprising:

heating and stirring the second reaction mixture under a nitrogen-gas atmosphere.

10. The method of claim 9 further comprising:

cooling the second reaction mixture to room temperature;

filtering a white precipitate from the second reaction mixture; and

concentrating the filtrate was concentrated to produce the trifluoromethyl-functionalized-poly(lactic acid) product.

11. The method of claim 10 further comprising:

dissolving the trifluoromethyl-functionalized-poly(lactic acid) in dry ethyl acetate;

filtering the trifluoromethyl-functionalized-poly(lactic acid) in dry ethyl acetate to remove any residual salts;

concentrating the filtrate under reduced pressure; and

purifying the concentrate by silica gel column chromatography using dry premium grade silica gel and a mixture of 30% dry ethyl acetate/hexanes as an eluent under nitrogen gas flow.

12. The method of claim 11 further comprising:

further purifying the concentrate by recrystallization in dry methylenechloride hexane to produce a white solid.