Trifluoroacetic acid → HCID 69588123, compound

Participants

Reaction Steps

To a stirred solution of N-(tert-butoxycarbonyl)-D-phenylalanine (11.0 g, 41.5 mmol) in chloroform (125 mL) was added 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (7.95 g, 41.5 mmol) and 1-hydroxybenzotriazole (5.60 g, 41.4 mmol). After 5 minutes, 2,2-diphenylethylamine (7.44 g, 37.7 mmol) was added. The reaction was stirred for 2 hours, diluted with chloroform (100 mL) and washed with aqueous sodium bicarbonate solution. The organic layer was dried (sodium sulfate) and concentrated to afford an off-white solid. Trituration with ether afforded the crude amide. This material was taken up in methylene chloride (100 mL) and treated with trifluoroacetic acid (45 mL, 580 mmol). After stirring for 15 minutes, the reaction was concentrated and the residue was partitioned between ethyl acetate and aqueous sodium bicarbonate. The organic layer was dried (sodium sulfate) and concentrated to afford 12.4 g (111% yield inflated by entrained residual solvent) of product as a colorless gum: 1H NMR (CDCl3) δ 7.34–6.95 (m, 15H), 4.10 (t, J=8.2, 1H), 3.88–3.79 (m, 2H), 3.68–3.61 (m, 1H), 3.49 (br s, 2H), 3.13–3.03 (m, 1H), 2.70–2.59 (m, 1H) ppm.

Provenance & Evidence