TANDEM KNOEVENAGEL CONDENSATION AND INTRAMOLECULAR CYCLOADDITION REACTIONS OF 2-AZIDOBENZALDEHYDES WITH 2-CYANOACETAMIDES IN THE SYNTHESIS OF 4-THIOCARBAMOYLTETRAZOLO[1,5- a ]QUINOLINES
The reaction of 2-azidobenzaldehydes with 2-thioamides of cyanoacetic acid proceeds without a solvent and presence of a base at 80–90°C selectively by one of the possible routes to form tetrazolo[1,5- a ]quinolines. The proposed mechanism of the reaction involves the Knoevenagel condensation and subsequent intramolecular [3+2] cycloaddition of the azide group at the S≡N bond of an intermediate acrylonitrile. Authors: Valery O. Filimonov, Vladimir T. Abaev, Tatyana V. Berezkina, Kristina A. Galata, Pavel A. Slepukhin, Maria A. Kostenko, Vera S. Berseneva*