反应详情

Z-Glu-Obzl (a N-α-Cbz-L-glutamic acid α-benzyl ester) (5 g, 13.46 mmol) was dissolved in 50 ml of dry THF at room temperature. N,N′-carbonyl diimidazole (1.1 eq) was added slowly and the mixture was then stirred for 2 hrs at room temperature. Ethyl magnesium malonate (0.55 eq) was added, and the mixture was stirred at room temperature overnight. The product was extracted with ether, and washed with 10% NaHCO3, water, and brine. The residue containing 3 was purified by flash chromatography on silica gel (ethyl acetate:hexanes 50:50) and concentrated on a rotary evaporator to afford a white solid in 40% yield. 1H-NMR (400 MHz, CDCl3): δ 1.26 (t, J=7.2, 3H), 1.9-2.01 (m, 1H), 2.1-2.28 (m, 1H), 2.5-2.7 (m, 2H), 3.37 (s, 2H), 4.18 (q, J=7.2, 2H), 4.41 (s, 1H), 5.11 (s, 2H), 5.18 (s, 2H), 5.44 (d, J=8, 1H), 7.25-7.41 (m, 10H). LC-MS (ESI) calcd for C24H2NO7 (M+H+) 442.18, obsd. 442.0.

1. stirringthe mixture was stirred at room temperature overnight
2. extractionThe product was extracted with ether
3. washwashed with 10% NaHCO3, water, and brine
4. additionThe residue containing 3
5. customwas purified by flash chromatography on silica gel (ethyl acetate:hexanes 50:50)
6. concentrationconcentrated on a rotary evaporator
7. customto afford a white solid in 40% yield