Ethyl trifluoroacetate → HCID 12040691, compound

Participants

Reaction Steps

O-Ethyl-L-tyrosine (IV, EXAMPLE 3, 20.9 g, 100 mmol) is suspended in methanol (100 mL), tetramethylguanidine (TMG) (12.5 mL, 100 mmol) is added, followed by ethyl trifluoroacetate (14 mL, 120 mmol). The mixture is stirred at 20-25 deg for 48 hr and the resulting mixture is concentrated to remove most of the methanol and excess ethyl trifluoroacetate. The residue is dissolved in water (40 mL), added hydrochloric acid (100 mL of 1.0 M) to adjust the pH<3. The mixture is stirred at 20-25° for at least 2 hr, then filtered. The precipitate is suspended in water (50 mL), stirred for 0.5 hr, then filtered. This wash process is repeated once. Then the precipitate is dried in oven at 55° for 48 hr to give the title compound, NMR (DMSO-d6) δ12.9, 9.72, 7.15, 6.82, 4.46, 3.98, 3.15, 2.92 and 1.31; CMR (DMSO-d6) δ171.8, 157.6, 157.7, 130.3, 129.0, 116.1, 63.2, 54.6, 35.1 and 15.0; FMR (DMSO-d6) δ-74.7; HRMS (FAB) calculated for C13H14F3NO4 [M+1]=306.0953, found=306.0952.

Provenance & Evidence