Synthesis of quinoxalines or quinolin-8-amines from N-propargyl aniline derivatives employing tin and indium chlorides

Org Biomol Chem. 2015 Sep 28;13(36):9373-80. doi: 10.1039/c5ob01532d. Epub 2015 Aug 17.

Abstract

Pyrazino compounds such as quinoxalines are 1,4-diazines with widespread occurrence in nature. Quinolin-8-amines are isomerically related and valuable scaffolds in organic synthesis. Herein, we present intramolecular main group metal Lewis acid catalyzed formal hydroamination as well as hydroarylation methodology using mono-propargylated aromatic ortho-diamines. The annulations can be conducted utilizing equal aerobic conditions with either stannic chloride or indium(iii) chloride and represent primary examples for main group metal catalyzed 6-exo-dig and 6-endo-dig, respectively, cyclizations in such settings. Both types of reactions can also be utilized in a one-pot manner starting from ortho-nitro N-propargyl anilines using stoichiometric amounts SnCl2·2H2O or In powder. Mechanistic considerations are presented regarding the substituent-depending regioselectivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aniline Compounds / chemistry*
  • Dose-Response Relationship, Drug
  • Indium / chemistry*
  • Molecular Structure
  • Quinolines / chemical synthesis*
  • Quinolines / chemistry
  • Quinoxalines / chemical synthesis*
  • Quinoxalines / chemistry
  • Structure-Activity Relationship
  • Tin Compounds / chemistry*

Substances

  • Aniline Compounds
  • Quinolines
  • Quinoxalines
  • Tin Compounds
  • Indium
  • stannous chloride
  • indium trichloride
  • aniline