NEW METHOD OF SYNTHESIS OF δ-CARBOLINES FROM 3-INDOLINONE VIA PYRANOINDOLES

Article abstract of DOI:10.1007/BF00504208

2-Arylidene-1-acetylindolin-3-ones were obtained from 1-acetylindolin-3-ones and p-substituted benzaldehydes or 4-pyridinecarboxaldehyde, by the action of malonodinitrile, and were converted into 2-amino-4-aryl-5-acetyl-3-cyanopyrano<3,2-b>indoles.When heated with an aqueous-alcoholic solution of KOH, the latter compounds transform into 2-alkoxy-4-aryl-3-cyano-δ-carbolines.The possible paths of formation of δ-carbolines and pyrano<3,2-b>indoles are discussed.