p-Toluenesulfonic acid → 6-Amino-1,3-dihydro-2H-indol-2-one

Participants

Reaction Steps

2,4-dinitrophenylacetic acic (10 g; 44 mmol) was dissolved in ethanol (200 mL) and purged with N2. 10% Pd/C (400 mg) was added and the reaction hydrogenated at 45 psi for 2 hours. The reacton was then transferred to a RBF and p-toluenesulfonic acid (150 mg) was added and the reaction heated at reflux overnight. The reaction was then filtered through celite to remove catalyst and concentrated. The product crashed out and was filtered as tan crystals 4.68 g (72% yield). 1H NMR (DMSO-d6, 400 MHz) δ 3.20 (s, 2H), 4.97 (br s, 2H), 6.07 (m, 2H), 6.76 (d, J=8.7 Hz; 1H), 10.05 (s, 1H); HPLC ret. time: 2.123 min. LRMS (M+) 148.7.

Provenance & Evidence