The invention relates to pyranone derivatives of general formula (I), wherein X is chlorine, bromine or iodine and R.sub.1 and R.sub.2 is independently a hydrogen atom, an alkyl, cycloalkyl or alkylene, linear or branched group containing 1-20 carbon atoms, optionally substituted by a hydroxyl, amino, ether or halogen group, or R.sub.1 and R.sub.2 form together a cycle of 5, 6, 7 or 8 members which is optionally substituted by a hydroxyl, amino, ether or halogen group including isomers, enantiomers, diastereoisomers and the mixtures thereof. A method for preparing the inventive derivatives and the therapeutic use thereof, in particular for treating cancer, are also disclosed.