反应详情

(3S)-3-[( -Benzylindole-2-carbonyl)alaninyl] amino-4-oxobutanoic acid, semicarbazone (176 mg, 0.37 mmol) was dissolved in methanol (4.5 mL), formaldehyde (1.5 mL, 37% wt. aq) and acetic acid (1.5 mL) and the resulting mixture was stirred for 4 hours under a nitrogen atmosphere at room temperature. The reaction mixture was concentrated in vacuo, diluted with water, and extracted twice with ethyl acetate. The ethyl acetate solution was washed with brine, dried over sodium sulfate, and concentrated to give a crude product which was triturated with ether to afford the title product as a light green powder (113 mg, 72%). TLC: (methylene chloride:methanol:acetic acid, 20:1:1, silica gel): Rf=0.38; MS for C23H23N3O5; M+H+=422; M−H+420. 1H-NMR (CD3OD): δ7.65 (d, J=8.0, 1H), 7.37 (dd, J=8.2, 0.8, 1H), 7.24-7.04 (m, 8H), 5.87-5.73 (m, 2H) 4.60-4.49 (m, 2H), 4.32-4.23 (m, 1H), 2.69-2.44 (m, 2H), 1.41 (d, J=7.1, 2 sets, 3H).

1. concentrationThe reaction mixture was concentrated in vacuo
2. additiondiluted with water
3. extractionextracted twice with ethyl acetate
4. washThe ethyl acetate solution was washed with brine
5. dry with materialdried over sodium sulfate
6. concentrationconcentrated
7. customto give a crude product which
8. customwas triturated with ether