1,3,5-Tribromobenzene Explained

1,3,5-Tribromobenzene is an aryl bromide and isomer of tribromobenzene, also known as sym-tribromobenzene.^[1]

Preparation

Brominating aniline with elemental bromine gives 2,4,6-tribromoaniline. This is then diazotized, then reacted with ethanol to replace the diazonium group with hydrogen, forming 1,3,5-tribromobenzene.^[2]

It has also been prepared by these methods:^[2]

• replacement of the amino group of 3,5-dibromoaniline with bromine
• the action of light on bromoacetylene, effecting an alkyne trimerisation to 1,3,5-tribromobenzene
• decomposition of 2,4,6-tribromophenylhydrazine
• reduction of 2,4,6-tribromobenzenediazonium sulfate
• a side product in the preparation of 2,4,6-tribromobenzonitrile

Reactions and uses

1,3,5-Tribromobenzene is a precursor to C₃-symmetric molecules. It undergoes a Suzuki reaction with three equivalents of 4-formylphenylboronic acid to form 1,3,5-tris(4-formylphenyl)benzene (TFPB), a monomer for covalent organic frameworks.^[3]

Notes and References

1. Web site: 1,3,5-Tribromobenzene . . 25 December 2023 .
2. . sym.-Tribromobenzene . Coleman . G. H. . Talbot . William F. . 1933 . 13 . 96 . 10.15227/orgsyn.013.0096.
3. Bunck . David N. . Dichtel . William R. . William Dichtel . Bulk Synthesis of Exfoliated Two-Dimensional Polymers Using Hydrazone-Linked Covalent Organic Frameworks . . 2013 . 135 . 40 . 14952–14955 . 10.1021/ja408243n. 24053107 .