Reaction #1747848

Reaction equation

DOPA

methanol

L-DOPA

methanol

methyl trifluoroacetate

→

N-trifluoroacetyl-L-DOPA

Solvents

water

Conditions

Workup

1. 1
   Otherequipped with a Teflon stirring bar
2. 2
   Otherrubber septum and purged with dry argon
3. 3
   workup.DISSOLUTIONhad completely dissolved (after about 24 hr)
4. 4
   FiltrationThe mixture was filtered
5. 5
   OtherThe filtrate was evaporated under reduced pressure
6. 6
   OtherThe crude product was re-crystallized from ethyl acetate
7. 7
   OtherUse of ester of N-hydroxysuccinimide in the synthesis of N-acrylamino acids

Procedure

1.97 g L-DOPA (10 mmol) and 5 ml of dry methanol was added into an oven-dried 25 ml round-bottomed flask equipped with a Teflon stirring bar and rubber septum and purged with dry argon. Then, 1.3 ml of TMG (10 mmol) and 1.4 ml of methyl trifluoroacetate (12.5 mmol) was added. The mixture was stirred vigorously at room temperature until DOPA had completely dissolved (after about 24 hr). At this point, the flask was immersed in cold water (0° C.) and 5 ml of methanol and 4 g Dowex 50 resin (H+ form) were added. The mixture was filtered after stirring for 10 min. The filtrate was evaporated under reduced pressure. The crude product was re-crystallized from ethyl acetate and the yield of N-trifluoroacetyl-L-DOPA was 78%. See Curphey, T. J. Trifluoroacetylation of amino acids and peptides by ethyl trifluoroacetate. J. Org. Chem. 1979, 44, 2805-2807; Lapidot, Y.; Rappoport, S.; Wolman, Y. Use of ester of N-hydroxysuccinimide in the synthesis of N-acrylamino acids. J. Lipid Research 1967, 8, 142-145.

Source