A Practical And Efficient Iodination Of BODIPY Derivatives With Hypervalent Iodine

BODIPY dyes have outstanding chemical, thermal, and photophysical properties such as high fluorescence quantum yields, long wavelength emission, relative insensitivity to environment perturbations. So BODIPY dyes are currently attracting much interest in a wide variety of research areas such as fluorescent switches, labeling reagents,chemosensors, long-wavelength absorbing/emitting fluorescent dyes, light-harvesting systems, supramolecular polymers, photodynamic therapy. Over past years, a number of research groups demonstrated that BODIPY derivatives have remarkably rich chemistry, making these dyes amenable to chemical modifications at many positions of the boradiazaindacene core. Among synthetic procedures for functionalized BODIPYs, iodination of BODIPYs is one of the most useful chemical modifications.They make the C-H bond of2-and6-positions of BODIPY activated, extending the entire conjugated system. After the introduction of iodine atoms, duing to the heavy atom effect, not only increases the absorption and emission wavelengths,but aslo widen the range of applications in more fields. For example, non-evasive applications in medical diagnostic techniques and the optical field of organic electronics, studying the photodynamic therapy.In this article, I first synthesize a series of BODIPY by three-step reaction,then approach for the mono-and diiodin-ation of1,3,5,7-substituted BODIPYs at2-or2,6-positions which was carried out with IOAc generated from the mixture of phenylio-dine(Ⅲ) diactate (PhI(OAc)2, PIDA) with I2in situ. By controlling the conditions, I successfully synthesize the diiodination of1,3,5,7-substituted BODIPYs at2,6-positions with2.2eq I2and2.0eq PhI(OAc)2in acetonitrile carried out at room temperature for10h. After varying the reaction conditions, it was found that the best choice for the monoiodination is:0.48eq I2and0.48eq PhI(OAc)2in CH3CN-EtOH (1:1, v:v) carried out at-25℃for12h to afford mono of1,3,5,7-substituted BODIPYs at2-positions.Compared with the traditional methods, using IC1or NIS as iodinated reagent, this approach for the iodination of BODIPYs has great advantages, such as safe, low-cost, high yield, easy to operate etc.