Substituted 2-nitro-β-piperidinostyrenes (2), obtained from the reaction of substituted 2-nitrotoluene (1), N,N-dimethylformamide dimethyl acetal or N,N-dimethylformamide diethyl acetal and piperidine in solvent of N,N-dimethylformamide, reacted with iron and acetic acid to yield the substituted indoles 3. Substituted indole-3-carboxaldehydes 4 and 5 were synthesized from 3 by Vilsmeier-Hacck reaction with phosphorus oxychloride and N,N-dimethylformamide. The structures of 4 and 5 were analyzed and established by elemental analysis, IR and ¹H NMR spectra.

Key words: synthesis, substituted indole-3-carboxaldehyde, Vilsmeier-Hacck reaction