1-(2-Phenylethyl)piperidin-4-amine → 5-fluoro-2-methyl-N-[1-(2-phenylethyl)-4-piperidyl]indole-3-carboxamide

Participants

Reaction Steps

A solution of 4.0 g of 5-fluoro-2-methylindole-3-carboxylic acid and 4.2 g of 4-amino-1-(2-phenylethyl)piperidine in 80 ml of tetrahydrofuran was allowed to stand for a while to precipitate a salt. To the suspension was added 4.7 g of dicyclohexylcarbodiimide and the mixture was stirred under reflux for 3 hours. After cooling, the precipitated dicyclohexylurea was filtered off and the filtrate was concentrated. The residue was crystallized by treatment of hexane. The crystals were filtered with suction and recrystallized from ethyl acetate to yield 3.7 g of 5-fluoro-2-methyl-N-[1-(2-phenylethyl)-4-piperidyl]indole-3-carboxamide, melting at 159°-162° C. The crude product (3.9 g) was recovered from the mother liquor.

Provenance & Evidence