21017-50-5Relevant articles and documents
Selective N-alkylation of indoles with α,β-unsaturated compounds catalyzed by a monomeric phosphate
Sunaba, Hanako,Kamata, Keigo,Mizuno, Noritaka
, p. 2333 - 2338 (2014/08/18)
Catalytic N-alkylation of indoles is challenging because the N1 nitrogen atoms are inert toward electrophilic reagents. Herein, an organic-solvent- soluble alkylammonium salt of a simple monomeric phosphate ion, [PO 4]3-, with a high charge density acts as an efficient homogeneous catalyst for selective N-alkylation of indoles with α,β-unsaturated compounds. For the reaction of indole with ethyl acrylate, the turnover number reached up to 36 and the turnover frequency was 216 h-1; these values are the highest among those reported for base-mediated systems so far. In the presence of [PO4]3- ions, various combinations of nitrogen nucleophiles (ten examples) and α,β-unsaturated compounds (four examples) were efficiently converted to the desired N-alkylated products in high yields. NMR and IR spectroscopies showed formation of the indolyl anion through the activation of indole by the [PO4]3- ion, which plays an important role in the present N-alkylation.
Synthesis of N-alkyl substituted bioactive indolocarbazoles related to G?6976
Roy, Sudipta,Eastman, Alan,Gribble, Gordon W.
, p. 7838 - 7845 (2007/10/03)
The syntheses of new nitrile and amide analogues of 7-keto G?6976 are described. The amide analogue 22 was formed via the condensation with a new functionalized indoleacetic acid derivative 25 to overcome the solubility problem during the coupling reaction.
