Succinic anhydride → (S)-4-(4-(2-(((9H-fluoren-9-yl)methoxy)carbonylamino)-3-methoxy-3-oxopropyl)phenylamino)-4-oxobutanoic acid

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Reaction Steps

Succinic anhydride (6.72 g, 67.2 mmol) was added to the solution of (S)-methyl 2-(((9H-fluoren-9-yl)methoxy)carbonylamino)-3-(4-aminophenyl)propanoate 3C from step 2. The reaction mixture was stirred at room temperature overnight. The solvent was removed, and the residual solid was washed with 30% ethyl acetate/petroleum ether (200 mL) and recrystallized in THF and 30% ethyl acetate/petroleum ether to give (S)-4-(4-(2-(((9H-fluoren-9-yl)methoxy)carbonylamino)-3-methoxy-3-oxopropyl)phenylamino)-4-oxobutanoic acid 3D as a white solid (19 g, 66% yield). 1HNMR (DMSO-d6, 300 MHz) δ: 10-9.9 (s, 1H), 8.0-7.9 (m, 3H), 7.8-7.6 (m, 2H), 7.6-7.5(m, 2H), 7.5-7.4(m, 2H), 7.4-7.3(m, 2H), 7.3-7.1(d, 2H), 4.4-4.2 (m, 4H), 3.8-3.6 (s, 3H), 3.1-2.8 (m, 2H), 2.7-2.5 (m, 4H); ESI-MS: m/z 517.3 (M+H)+.

Provenance & Evidence