Trifluoroacetic acid → D-Trp-Lys(CBZ)-OtBu

Participants

Reaction Steps

To a solution of 2.95 gm of BOC-D-Trp-Lys(CBZ)-OtBu (4.7 mmol) in 200 mL of methylene chloride was added 10 mL of trifluoroacetic acid. The reaction (see Scheme 1A, for reaction of 3→2) was stirred for 2 hr, and the solvent was rapidly removed under reduced pressure at less than 35 C. The oil was partitioned between 300 mL of methylene chloride and 100 mL of 50% saturated aqueous sodium bicarbonate solution. The layers were separated, the organic layer was washed with 100 mL of saturated brine, dried over anhydrous magnesium sulfate, filtered, and the solvent removed under reduced pressure to yield 2.50 gm (100%) of D-Trp-Lys(CBZ)-OtBu.

Provenance & Evidence