The Chemistry of Ethyl 3-(2-Ethoxy-2-oxoethyl)-1H-indole-2-carboxylate: Synthesis of Pyrimido[4,5-b]indoles and Diethyl 4-Hydroxyquinoline-2,3-dicarboxylate via Intramolecular Cyclizations

KAPTI T., DENGİZ Ç., BALCI M.

SYNTHESIS-STUTTGART, vol.49, no.8, pp.1898-1904, 2017 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 49 Issue: 8
  • Publication Date: 2017
  • Doi Number: 10.1055/s-0036-1588119
  • Journal Name: SYNTHESIS-STUTTGART
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1898-1904
  • Keywords: azides, condensation, heterocycles, indole, oxidation, RECEPTOR TYROSINE KINASE, INDOLE-DERIVATIVES, WINTERFELDT-OXIDATION, BIOLOGICAL-ACTIVITY, INHIBITORS, RIBONUCLEOSIDES, POTENT, AGENTS, CELLS
  • Middle East Technical University Affiliated: Yes

Abstract

We report the synthesis of a new series of 2-oxo-1,2,4,9-tetrahydro- 3H-pyrimido[4,5-b] indole derivatives and diethyl 4-hydroxyquinoline- 2,3-dicarboxylate starting from ethyl 3-(2-ethoxy-2-oxoethyl)- 1H-indole-2-carboxylate. Intramolecular cyclization formed the target ring systems. The key substrates featuring both acyl azide and isocyanate functionalities were prepared from bis(acyl azide) intermediate. The acyl azide functionalities directly connected to methylene groups were regiospecifically converted into urea and urethanes via the reactive isocyanate intermediates. Thermal treatment of urea and urethanes provided the target 2-oxo-1,2,4,9-tetrahydro-3H-pyrimido[4,5b] indoles. Furthermore, ozonolysis of the starting indolediester substrate and subsequent base treatment to diethyl 4-hydroxyquinoline-2,3-dicarboxylate are described.