3-Methyl-2-butanone → 5-BROMO-2,3,3-TRIMETHYL-3H-INDOLE

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Reaction Steps

To a 500 mL flask were added p-bromophenylhydrazine 1 (50.3 g, 0.27 mol) glacial acetic acid (300 mL) and 3-methylbutanone (40 mL, 0.37 mol). The mixture was heated at reflux for 4 h and then cooled to rt. The volatile components were removed in vacuo and the residue was partitioned between petroleum ether (350 mL) and water (100 mL). The aqueous phase was washed again with petroleum ether (2×100 mL). The combined organic solutions were dried (MgSO4) and filtered and the solvent was evaporated in vacuo to afford 5-bromo-2,3,3-trimethyl-3H-indole 2 (56.3 g, 87%).

Provenance & Evidence