高効率臭素化試薬

ジブロモイソシアヌル酸 (DBI)はGottardiらによって報告された臭素化試薬で，その臭素化能はNBSなどよりも強力です。温和な条件下で，ニトロベンゼンなどのような求電子置換反応に不活性な芳香環に臭素を効率良く導入することが可能です。

[1] W. Gottardi, Monatsch. Chem. 1968, 99, 815. DOI: 10.1007%2FBF00901238

Dibromoisocyanuric acid (DBI) in conc. sulfuric acid has been found to be a powerful brominating agent for aromatic compounds having strongly deactivating substituents. The use ofDBI for monobromination and the dependence of the very high reaction rate on the reaction conditions is described. Comparison with other brominating methods and agents of the N−Br-type shows the superiority ofDBI.

[2] “2,3-Dihydroxy-3-{3-[3-(trifluoromethyl)diazirin-3-yl]phenyl}propionic Acid. A Cleavable Carbene-Generating Reagent Used for Photocrosslinking”

A. A. Kogon, D. E. Bochkariov, B. P. Baskunov, A. V. Cheprakov, Liebigs Ann. Chem. 1992, 879　DOI: 10.1002/jlac.1992199201145

The synthesis of 2,3-dihydroxy-3-{3-[3-(trifluoromethyl)diazirin-3-yl]phenyl}propionic acid (8), a new cleavable carbenegenerating reagent used in photocrosslinking experiments in molecular biology is described. This synthesis starts with the bromination of trifluoroacetophenone. The resulting compound 2 is converted into the corresponding diazirine 6 via oxime 3, O-tosyloxime 4, and diaziridinyl 5 derivatives. The cleavable cis-diol bond is formed via a cinnamic acid derivative 7 by permanganate oxidation resulting in the title compound 8.

[3] “Conjugated polymers based on benzodithiophene and arylene imides: Extended absorptions and tunable electrochemical properties”

J. Chen, M.-M. Shi, X.-L. Hu, M. Wang, H.-Z. Chen, Polymer 2010, 51, 2897. DOI: 10.1016/j.polymer.2010.04.035

Three novel conjugated polymers have been designed and synthesized via the alternative copolymerization of the electron-donating monomer benzodithiophene (BDT) and three different electron-accepting monomers: perylene diimide (PDI), naphthalene diimide (NDI), and phthalimide (PhI). All obtained copolymers show good solubility in common organic solvents as well as broader absorptions in visible region and narrower optical band gaps compared to homopolymers from BDT units. It is found that the absorptions of the copolymers are red-shifted with increasing the electron-withdrawing ability of the co-monomer. In particular, the absorption edge of P(BDT-NDI) film extends to 760 nm, whereas that of P(BDT-PhI) film is only at 577 nm. Cyclic voltammograms of the three polymers disclose that P(BDT-PDI) and P(BDT-NDI) are typical n-type materials because PDI and NDI are strong electron-accepting groups, while P(BDT-PhI) is a stable p-type material where the weak electron-withdrawing monomer (PhI) is introduced. The results suggest that the absorption range and the electrochemical properties of the conjugated polymers can be tuned by appropriate molecule-tailoring, which will help exploring ideal conducting polymers for potential applications in polymer optoelectronics, especially in polymer solar cells.