Phosphorohydrazines of 4-oxo-4H-1-benzopyran and 1-benzopyran-2,4-dione exhibit antitumor activity against L1210 leukemia.

Phosphorohydrazines and phosphorohydrazones of benzopyran-2,4-dione as well as the phosphorohydrazone of 4-hydroxycoumarine were tested for antitumor activity in lymphatic leukemia L1210 bearing mice.