5-chloro-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole → 4-(5-chloro-[1H]-indol-3-yl)-piperidine

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Reaction Steps

Crude 5-chloro-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole 8a (26 g) was dissolved in glacial acetic acid (330 ml) and PtO2 (0.7 g) was added. The mixture was hydrogenated in a Parr apparatus at 3 atm. for 5 hours. The catalyst was filtered off and excess acetic acid evaporated in vacuo. Water was added and pH was adjusted to >9 by addition of diluted aqueous NH4OH. Extraction with ethyl acetate (2×200 ml) and work-up of the combined organic phases yielded 19 g of crude title compound as a visceous oil.

Provenance & Evidence