Ethyl 3-(2,4-diaminophenyl)propanoate → 7-amino-3,4-dihydro-1H-quinolin-2-one

Participants

Reaction Steps

A suspension of Pd(OH)2/C (10%, 3.0 g) and (E)-ethyl 3-(2,4-dinitrophenyl)acrylate (12.0 g, 45.1 mmol) in MeOH (80 mL) was stirred at 25° C. under an atmosphere of H2 (45 psi) for 15 h. The mixture was filtered and the filtrate was concentrated in vacuo to give 3-(2,4-diamino-phenyl)-propionic acid ethyl ester (8.6 g, 98%), which was used directly in the next step without further purification. A solution of ethyl 3-(2,4-diaminophenyl)propanoate (8.6 g, 41.3 mmol) in EtOH (50 mL) was stirred at 85-100° C. for 48 h. The reaction mixture was cooled to ambient temperature and the solvent was removed in vacuo. EtOAc (10 mL) was added to the residue and the precipitate was collected by filtration to give 7-amino-3,4-dihydro-1H-quinolin-2-one (5.8 g, 87%). 1H NMR (DMSO-d6, 400 MHz): δ 9.83 (brs, 1H), 6.76 (d, J=7.6 Hz, 1H), 6.12 (m, 2H), 4.95 (brs, 2H), 2.65 (t, J=7.2 Hz, 2H), 2.36 (t, J=7.2 Hz, 2H).

Provenance & Evidence