Synthesis of polyfluorinated 4‑hydroxyquinolin-2(1H)‑ones based on the cyclization of 2-alkynylanilines with carbon dioxide

Abstract

Convenient and efficient synthesis of polyfluorinated 4-hydroxyquinolin-2(1H)-ones from the corresponding o-alkynylaniline derivatives and CO2 (1 atm), mediated by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and AgNO3 in acetonitrile was performed. This synthetic methodology may be used to prepare fluorinated heterocycles containing peripheral alkynyl and amino groups but is not suitable for silylethynyl derivatives that give indoles as the main products. The reaction takes place under mild conditions (60 °C) and involves readily available starting materials that include cheap and renewable carbon dioxide.