5,6-difluoro-2,3-dihydro-1H-indole-2,3-dione → 5-Fluoro-6-methylthioindole-2,3-dione

Participants

Reaction Steps

Sodium thiomethoxide (5.93 g, 84.6 mmol) was added to a solution of 5,6-difluoroindole-2,3-dione (7.75 g, 42.3 mmol) in dimethylformamide (400 mL). The reaction was stirred at room temperature for 1 h, then poured onto ice (2 L). The resulting solid was collected by filtration, washed with water and dried at 40° C. under vacuum to give a brown solid (3.12 g, 35%): mp 296° C.; C9H6F1NO2S requires: C, 51.18; H, 2.86; N, 6.63; S, 15.18%. Found C, 50.95; H, 2.85; N, 6.58; S, 15.35%; IR νmax (Nujol)/cm−1 3285, 2925, 2854, 1760, 1714, 1611, 1465 and 1036; NMR δH (400 MHz, DMSO-d6) 2.58 (3H, s), 6.71 (1H, d, J 6.0 Hz), 7.38 (1H, d, J 9.0 Hz), 11.02 (1H, brs).

Provenance & Evidence