Ethyl 4-oxo-1-piperidinecarboxylate → Ethyl 8-fluoro-1,3,4,5-tetrahydro-2H-pyrido[4,3-b]indole-2-carboxylate

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Reaction Steps

Plattner et al. and Harbert et al. also describe the earliest synthesis of flutroline: p-Fluorophenylhydrazine is condensed with N-carbethoxy-4-piperidone to form 8-fluoro-2-carbethoxy-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole. By the Ullman reaction the latter is arylated to form the 5-(p-fluorophenyl) derivative and then hydrolyzed under vigorous basic conditions to yield 8-fluoro-5-(p-fluorophenyl)-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole. The synthesis of flutroline is completed by 2-alkylation with 3-(p-fluorobenzoyl)propyl chloride and finally reduction of the ketone group to an alcohol group.

Provenance & Evidence