Synthesis, Crystal Structure and Antineoplasmic Activity of 3,6,8-Tribromo-5-hydroxy-2,7-dimethoxy-2-phenyl-2,3-dihydrochromen-4-one

The reaction of 5-hydroxyl-7-methoxyflavone (tectochrysin) with bromine obtained 3,6,8-tribromo-5-hydroxy-2,7-dimethoxy-2,3-dihydrochromen-4-one (1), which was characterized by FT-IR, H-1-NMR, C-13-NMR, elemental analysis and X-ray single-crystal diffraction. Complex 1 belongs to the monoclinic system, space group pbca with a = 9.4673(8), b = 17.9938(15), c = 21.2004(17) angstrom, V = 3611.5(5) angstrom(3), Z = 8, mu = 0.6726 mm(-1), D-c = 1.795 g/cm(3), F(000) = 2080, the final R = 0.0358 and wR = 0.0644 with I > 2 sigma(I). The results show that the addition reaction occurs at the carbon-carbon double bond (C2 and C3) of tectochrysin and 1 belongs to dihydroflavone. The reaction mechanism was discussed and the structure revealed that the crystal structure of 1 is stabilized by intramolecular hydrogen bonds and C-Br center dot center dot center dot pi interactions. The antitumor ability of 1 was evaluated against human leukemia cells (K562), human breast cancer cells (MCF-7) and human lung cancer cells (A549). 1 exhibited potent antitumor activities against human leukemia cells (K562) with the IC50 values of 18.9 mu mol/L.