Zur Chemie der Ketene

Abstract

A number of examples shows that reactive malonic acid derivatives (i. e. chlorides, mixed anhydrides, phenyl esters, and anilides of the unsubstituted or monosubstituted malonic acid) react on the one hand with CO- and CN-multiple bond systems and on the other hand with 1,3-H-active systems sometimes surprisingly easy to yield heterocyclic compounds. Intermediates in these reactions are derivatives of “ketene carboxylic acid” as proofed with different systems.