Synthetic access to poly-substituted 6-alkoxyindoles from 1,3-cyclohexanediones and nitroolefins through facile aromatization reaction.
6-Alkoxy-3-arylindoles were efficiently prepared from 1,3-cyclohexanedione enol ethers and beta-nitrostyrenes. Michael addition using the kinetically generated enolate, followed by Zn reduction of a nitro group of the resulting adducts produced the nitrones which were then treated with acetic anhydride to induce aromatization by dehydration and N-acetylation, which furnished the desired indoles by the DDQ oxidation. This methodology provides an easy entry toward various poly-substituted 6-alkoxyindoles.
Ma
Li-Jian
LJ
Department of Medicinal and Bioengineering Science, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.
Li
Xiao-Xia
XX
Kusuyama
Tomoyo
T
El-Sayed
Ibrahim El-Tantawy
Iel-T
Inokuchi
Tsutomu
T
D000475:Alkenes / Q000737:chemistry; D003512:Cyclohexanones / Q000737:chemistry*; D004987:Ethers / Q000737:chemistry; D006841:Hydrocarbons, Aromatic / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis*; D008722:Methods; D009574:Nitro Compounds / Q000737:chemistry*; D013343:Styrenes / Q000737:chemistry
D000475:Alkenes; D003512:Cyclohexanones; D004987:Ethers; D006841:Hydrocarbons, Aromatic; D007211:Indoles; D009574:Nitro Compounds; D013343:Styrenes; C004636:1,3-cyclohexanedione