The preparation of 2-substituted-3-diazoquinolin-4-ones

A series of 2-substituted-3-diazoquinolin-4-ones is prepared by the reaction of 2-substituted-3-amino-4-chloroquinolines with sodium nitrite in sulfuric acid. Some of the obtained products are then utilised in triazole formation, reduction and a Wolff rearrangement/Friedel–Crafts ketene capture.