6-Hydroxymethylindole → 1H-Indole-6-carboxaldehyde

Participants

Reaction Steps

Manganese dioxide (240 g) was added to a mechanically stirred solution of 6-hydroxymethylindole (40.7 g) in methylene chloride (1.6 liter). The mixture was stirred for 18 hr, filtered through a pad of diatomaceous earth, the filter cake washed with methylene chloride and chloroform, and the filtrate evaporated to give 6-formylindole (30.55 g) as a yellow solid. The filter cake was washed with tetrahydrofuran and the washings evaporated to give a further crop of 6-formylindole (2.35 g, 82% combined yield); partial NMR (250 MHz, DMSO-d6): 6.58(m, 1H, H3 -indole), 10.00(s, 1H, CHO), 11.71(br s, 1H, NH).

Provenance & Evidence