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TCI Practical Example: Bromination Reaction Using Dibromoisocyanuric Acid

We are proud to present the bromination reaction of 2,6-dinitrotoluene using dibromoisocyanuric acid (DBI).　DBI is a more powerful brominating agent than NBS and can efficiently introduce a bromo group into aromatic rings that are inert to electrophilic substitution reactions such as nitrobenzene.

Used Chemicals

• 2,6-Dinitrotoluene
• Dibromoisocyanuric Acid (= DBI) [D3753]
• conc. Sulfuric Acid

Procedure

Dibromoisocyanuric acid (433 mg, 1.51 mmol) was added to a solution of 2,6-dinitrotoluene (500 mg, 2.75 mmol) in conc. sulfuric acid (3 mL) and stirred at room temperature for 1.5 hours. Then the solution was poured into iced water. The aqueous layer was extracted with ethyl acetate and the organic layer was dried over anhydrous sodium sulfate and filtered. The solvent was removed under reduced pressure and the residue was purified by silica gel column chromatography (dichloromethane:hexane = 0:100 - 20:80) to give 5-bromo-2-methyl-1,3-dinitrobenzene as a white solid (501 mg, 70% yield).

Experimenter’s Comments

The reaction mixture was monitored by UPLC.
Both bromo groups of DBI can be used for bromination.

Analytical Data

5-Bromo-2-methyl-1,3-dinitrobenzene

¹H NMR (270 MHz, CDCl₃); δ 8.14 (s, 2H), 2.53 (s, 3H).

Lead Reference

• 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.

Other Reference

• A Concise Total Synthesis of Breitfussin A and B
  • S. Pandey, Y. Guttormsen, B. E. Haug, C. Hedberg, A. Bayer, Org. Lett. 2015, 17, 122.