Diethyl Ether → (3S)-3-[(1-Methylindole-2-Carbonyl)Leucinyl]Amino4-Oxobutanoic Acid, t-Butyl Ester Semicarbazone

Participants

Reaction Steps

1-Methylindole-2-carboxylic acid (70 mg, 0.4 mmol) and 3(S)-(Leucinyl)amino-4-oxobutanoic acid, t-butyl ester semicarbazone (131 mg, 0.4 mmol) were dissolved in methylene chloride (2 mL) and both DMAP (49 mg, 0.40 mmol) and EDAC (107 mg, 0.56 mmol) were added to the solution under a nitrogen atmosphere at 0° C. Stirring was continued for 1 hour at 0° C. and an additional 3 hours at room temperature. The reaction mixture was partitioned between ethyl acetate and 5% KHSO4 solution. The ethyl acetate solution was washed successively with 5% KHSO4 solution, saturated with sodium bicarbonate solution (2×) and brine, dried over sodium sulfate, and concentrated in vacuo to give a crude solid. Trituration of the solid with ether afforded the title product as a white powder (156 mg, 80%). TLC: (methanol/methylene chloride: 5/95, silica gel): Rf=0.42; 1H NMR (CDCl3+CD3OD): δ 8.18 (s, 1H), 7.66-7.11 (m, 6H), 6.97 (s, 1H), 6.32 (d, J=7.7, 1H), 4.95-4.88 (m, 1H), 4.70-4.62 (m, 1H), 4.03 (s, 3H), 2.82-2.56 (m, 2H), 1.87-1.58 (m, 3H), 1.38 (9H), 1.00 (t, J=6.3, 6H).

Provenance & Evidence