The condensation of isatin with enolisable acyclic and alicylcic 1:3-diketones has been investigated and the structures of the acylated cinchoninic acids obtained have been determined. The condensation of acetonylacetone with potassium isatate is also described. Condensation of isatin with 1:3-cyclohexadiones in neutral or acid media has been shown to give products different from those in alkaline