Synthesis of indole-3-thiocarboxaldehyde

Thiocarbonyl compounds from β-substituted vinylald- and -ketimmonium derivatives

“…It was prepared by treatment of the corresponding Vilsmeier salt (9b) with aqueous sodium hydrosulfide. Under these conditions N -[(3-indolyl)methylene]-N ,N -dimethylimmonium perchlorate (9a) is hydrolyzed to 3-formylindole [18].…”

“…Thials 10a, c-e have been synthesized by the action of anhydrous sodium hydrosulfide or hydrogen sulfide on the corresponding methineimmonium salts 9 in DMSO or DMF in the temperature range −20 to 20 • C (scheme 6) [9,18].…”