Formation of trialkyl quinoline-2,3,4-tricarboxylates by reaction of isatin, dialkyl acetylenedicarboxylates, and sodium O-alkyl carbonodithioates

An efficient one-pot synthesis of quinoline-2,3,4-tricarboxylates is described by reaction of isatin (indoline-2,3-dione) and electron-deficient acetylenic esters in the presence of sodium O-alkyl carbonodithioates, themselves prepared by addition of sodium hydride to a solution of an alcohol in CS2.