Reaction of Tertiary 2‐Chloroketones with Cyanide Ions: Application to 3‐Chloroquinolinediones

3‐Chloroquinoline‐2,4‐diones react with cyanide ions in dimethyl formamide to give 3‐cyanoquinoline‐2,4‐diones in small yields due to the strong hindrance of the substituent at the C‐3 atom. Good yields can be achieved if the substituent at this position is the methyl group. In the methanol solution, the reaction proceeds by an addition mechanism to form 2‐oxo‐1a,2,3,7b‐tetrahydrooxireno[2,3‐ c ]quinoline‐7b‐carbonitriles, from which...