The C‐3 brominated and iodinated derivatives were prepared from the corresponding 2‐arylquinolin‐4(1H)‐ones and their NMe‐4‐oxo derivatives using pyridinium tribromide in acetic acid or iodine‐Na2CO3 mixture in THF. The results of further studies of chemical transformation of the prepared α‐haloenones and preliminary antitumour activity of the 3‐bromo NH‐4‐oxo and NMe‐4‐oxo derivatives are also described.