An Efficient And Convenient Bromination Of BODIPY Derivatives With Copper (Ⅱ) Bromide

Boron-dipyrromethene (BODIPY), as a kind of important fluorescent dyes, have excellent photochemical physical characteristics such as high fluorescence quantum yields, sharp absorption and fluorescence emission spectacular and high Photochemical stability. So more and more research on the modification of BODIPY is increasing for the applications on ion probe, molecular switches, near-IR absorbing/emitting dyes, photodynamic therapy and other fields. These modifications include, (1) introduction of electron-donating moieties, (2) replacement of a C atom by a N atom, (3) rigidification of rotatable moieties, (4) extension of theπ-conjugation by introduction of methylene structures, and (5) the extension of theπ-conjugation by the fusion of aryl moieties. In particular, the fusion of aryl moieties is expected to result in an extension of theπ-system. Simple considerations of mesomeric structures reveal that the 2-and 6-positions of the BODIPY core bear the least positive charge, so it is difficult that reaction directly at this position to extendπ-conjugation. The application of BODIPYs is limited because of this content.In this thesis, dibromides BODIPYs(series 2) and monobromide BODIPYs(series 3) was been successfully synthesized by ethyl acetoacetate via seven-step reaction. In my design reaction, the traditional brominated agent NBS and Br2 was replaced the new brominative reagent CuBr2, and the toxic solvent CCl4 and C6H6 was replaced by CH3CN. Then the bromination reaction could be carried out at room temperature efficiently. This new method is safer, lower cost, more environmentally friendly, which also meets the requirement of the direction of development of green chemistry.BODIPY also has actual and potential applications. After the introduction of bromine atoms,1) the C-H bond of 2-and 6-positions of BODIPY is activated, which provide a new method to extendπ-conjugation,2) the absorption and fluorescence emission spectacular is Red-shifted,3) after bromination, the process of the singlet-oxygen generation is promoted because of heavy-atom effect. This singlet-oxygen can kill cancer cells, therefore bromidative BODIPYs can be used as Photodynamic therapy as photosensitizer.