Hydrochloric Acid → 1-Isopentylindolin-2-one

Participants

Reaction Steps

The above 1-isopentylisatin was redissolved in DMSO (15 mL). N2H4-xH2O (3 mL) was added dropwise over 10 min. After addition, the reaction mixture was stirred for 5 min at rt, then 2 h at 140° C. (oil temp.) before cooling to rt. Ice/H2O (30 mL) was added, followed by 6 M HCl (10 mL, 60 mmol) and the resulting mixture was stirred for 30 min at rt. Additional ice/H2O (50 mL) was added and the mixture was extracted with EtOAc (3×50 mL). The crude product was purified by flash chromatography (gradient: EtOAc/hex 0 to 20%) to afford the title compound as an orange red liquid (4.30 g, 71% over two steps). 1H NMR (400 MHz, DMSO-d6) δ 7.27-7.22 (m, 2H), 7.02-6.95 (m, 2H), 3.65 (t, J=7.4 Hz, 2H), 3.33 (s, 2H), 1.60-1.52 (m, 1H), 1.44 (q, J=7.2 Hz, 2H), 0.92 (d, J=6.4 Hz, 6H); MS ESI 203.9 [M+H]+, calcd for [C13H17NO+H]+ 204.1.

Provenance & Evidence