title: Regioselective stepwise bromination of boron dipyrromethene (BODIPY) dyes.
abstract: Halogenated BODIPYs are important synthetic precursors and potential sensitizers for photodynamic therapy (PDT). Electrophilic bromination of pyrrolic-unsubstituted BODIPYs using bromine regioselectively generated mono- to heptabromoBODIPYs in a stepwise fashion in good to excellent yields. These resultant bromoBODIPYs were applied for regioselective substitution and Suzuki coupling reaction to generate BODIPYs 4, 5, 6, and 7 in good to excellent yields. According to NMR and X-ray analysis results, the stepwise bromination first takes place at 2,6-, then at 3,5-, and eventually at 1,7-positions, whereas the regioselective substitution occurs first at 3,5- then at 1,7-positions of the chromophore. The spectroscopic properties of these resultant BODIPYs were studied, which shows the potential application of these bromoBODIPYs as sensitizers for PDT.
authors.affiliation: Laboratory of Functional Molecular Solids, Ministry of Education, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, China. jiao421@mail.ahnu.edu.cn
authors.forename: Lijuan
authors.initials: L
authors.lastname: Jiao
authors.forename: Weidong
authors.initials: W
authors.lastname: Pang
authors.forename: Jinyuan
authors.initials: J
authors.lastname: Zhou
authors.forename: Yun
authors.initials: Y
authors.lastname: Wei
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Mu
authors.forename: Guifeng
authors.initials: G
authors.lastname: Bai
authors.forename: Erhong
authors.initials: E
authors.lastname: Hao