293744-33-9

Upstream product

• 280115-99-3 tert-butyl 4-(chlorocarbonyl)-piperidine-1-carboxylate 
• 13296-94-1 2-bromo-4-nitroaniline 
• 100-44-7 benzyl chloride 
• 293744-28-2 tert-butyl 4-{[(2-bromo-4-nitrophenyl)amino]carbonyl}piperidine-1-carboxylate 
• 84358-13-4 N-[(tert-butoxy)carbonyl]piperidine-4-carboxylic acid 

Relevant academic research and scientific papers

A convenient synthetic route to spiro[indole-3,4'-piperidin]-2-ones

Starting from 1-[(tert-butoxy)carbonyl]piperidine-4-carboxylic acid and 2-bromoaniline, the spiro[indole-3,4'-piperidin]-2-one system was obtained in three high-yielding steps: anilide formation, N(1)-protection, and intramolecular cyclization under Pd catalysis as the key reaction. The preparation of the corresponding 2-bromoanilide was studied. In extension, the same sequence was developed with 4-methyl- and 4-nitro-2-bromoaniline. In the key step, the NO2 group led to a rather diminished yield. The transformation of the protected spiro[indole-3,4'-piperidin]-2'one to the corresponding unprotected dihydroindoles is discussed.