tert-butyl 7-nitro-3,4-dihydroquinoline-1(2H)-carboxylate → tert-Butyl 7-amino-3,4-dihydroquinoline-1(2H)-carboxylate

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Reaction Steps

A suspension of the crude 7-nitro-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester (4.5 g, 16.2 mol) and 10% Pd—C (0.45 g) in MeOH (40 mL) was stirred under H2 (1 atm) at room temperature overnight. After filtration, the filtrate was concentrated and the residue was purified by column chromatography (petroleum ether-EtOAc, 5:1) to give tert-butyl 7-amino-3,4-dihydroquinoline-1(2H)-carboxylate (DC-1) as a brown solid (1.2 g, 22% over 2 steps). 1H NMR (CDCl3) δ 7.15 (d, J=2 Hz, 1H), 6.84 (d, J=8 Hz, 1H), 6.36-6.38 (m, 1H), 3.65-3.68 (m, 2H), 3.10 (br s, 2H), 2.66 (t, J=6.4 Hz, 2H), 1.84-1.90 (m, 2H), 1.52 (s, 9H); ESI-MS 496.8 m/z (2M+H+).

Provenance & Evidence