Mild reaction conditions and simple workup provides a practical and commercially viable route for the synthesis of bromo compounds of deactivated aromatics. General structure: ArOH (Ar is an aromatic ring) Phenols have an aromatic ring bonded directly to a hydroxyl (–OH) group. Simple experiment to show the reaction of a phenol derivative with bromine. Alpha Bromination. Some phenols are shown below. If bromine water is added to a solution of phenol in water, the bromine water is decolourised and a white precipitate is formed which smells of antiseptic. Notice the multiple substitution around the ring - into all the activated positions. References: 1) Smith, M. B.; March's Advanced Organic Chemistry, 7th Edition.

DOI: 10.1021/jo802772d. Highly deactivated aromatic compounds were smoothly monobrominated by treatment with N-bromosuccinimide (NBS) in concentrated H2SO4 medium affording the corresponding bromo derivatives in good yields. In summary, we have developed a highly selective Cu-catalyzed process for the oxidative nuclear monobromination of phenol and electron-rich phenolic compounds under mild aerobic conditions. Bromine is quite volatile even at The importance of axial chirality in enantioselective synthesis has been widely recognized for decades. A broad scope of arenes was investigated, including the benzimidazole and carbazole core as well as analgesics such as naproxen and paracetamol. This phenoxide ion formed is highly reactive towards electrophilic substitution reactions.

The use of an inexpensive copper catalyst, lithium bromide, as a source of bromine and dioxygen as a final oxidant is a significant practical advantage. A practical electrophilic bromination procedure for phenols and phenol – ethers was developed under e ffi cient and very mild reaction conditions. The Journal of Organic Chemistry 2009, 74 (12) , 4547-4553.
However, phenol is toxic and can cause burns to the skin. Paul D. O’Shea, Danny Gauvreau, Francis Gosselin, Greg Hughes, Christian Nadeau, Amélie Roy and C. Scott Shultz. A Friedel-Crafts Alkylation of … Equation (1) OH OH Br Br Br + 3Br2 + 3HBr This reaction may be used as a basis for phenol analysis. Syntactic fantastic: A practical, ortho- selective mono-halogenation and phenylselenation of phenols by direct C-H halogenation. 3. When phenol is treated with bromine water, a white precipitate of 2, 4, 6-tribromophenol is formed.

When phenol is treated with sodium hydroxide, phenoxide ion is formed. A practical electrophilic bromination procedure for phenols and phenol–ethers was developed under efficient and very mild reaction conditions. Alpha bromination generally involves enolizable ketones.

The precipitate is 2,4,6-tribromophenol. Expt. When phenol is treated with bromine water, a white precipitate of 2, 4, 6-tribromophenol is formed. Uses Dilute solutions of phenol are used as disinfectants and phenol was probably the first antiseptic. Chem 2700, Organic Chemistry I, Dept. Bromination of Phenol with Bromine, NBS, and N-Bromodibutylamine (NBB) a) Product yield (%) b) Recovery (%) Reagent Reagent 2,6-dibromo-2,4,6-tribromo-2-bromo-2,4-dibromo-4-bromo- / PhOH phenol phenol phenol phenol phenol Br 2 1.0 --10.7 1.0 85.7 2.6 Br 2 2.0 -0.8 1.0 95.1 3.0 - NBS 1.0 1.0 1.5 74.5 1.4 20.4 2.5 NBS 2.0 11.0 35.2 21.9 17.2 14.6 1.2 NBB 1.0 28.8 0.7 30.8 2.1 1.9 35.7 … Formation of 2, 4, 6-tribromophenol. Efficient and Practical Oxidative Bromination and Iodination of Arenes and Heteroarenes with DMSO and Hydrogen Halide: A Mild Protocol for Late-stage Functionalization Song Song†, Xiang Sun†, Xinwei Li†, Yizhi Yuan†, and Ning Jiao* † State Key Laboratory of Natural and Biomimetic Drugs, Peking University, School of Pharmaceutical Sciences, Peking University, Xue Yuan Rd.

Written By Dr John Studley on 16th October 2018.