Bromine → 8-bromo-1-chloro-5H-pyrido[4,3-b]indole-4-carboxamide

Participants

Reaction Steps

To a suspension of 1-chloro-5H-pyrido[4,3-b]indole-4-carboxamide (Example 10 Step 3) in AcOH (0.15 M) at room temperature was added Br2 (10 equiv) to provide a homogeneous mixture. After standing at room temperature a precipitate formed, and after 1 h, a suspension of Zn powder (excess) in THF was added in a cold water bath. After a period of 10 min, the reaction mixture was poured over THF/EtOAc and saturated NaHCO3. After separation of the organic phase, the aqueous phase was extracted again with THF/EtOAc, and the combined organic phases were washed with brine, dried over MgSO4 and filtered. After evaporation of the organic solvents, the residue was purified by flash chromatography (10-70% EtOAc in hexanes) to provide the title compound as a yellow solid.

Provenance & Evidence