Ultrasound-Assisted Bromination of Aromatic Rings Using NaBr/H₂ O₂ System

Abstract

An ultrasound‐assisted bromination of aromatic rings is described. The reactions were performed in the presence of sodium bromide and hydrogen peroxide. The reactions have shown to be extremely quick, mild and efficient; and the brominated products were obtained in excellent yields and selectivities.

Facial Syntheses of Bromobenzothiazines via Catalyst-Free Tandem C–H Amination/Bromination in Water

“…Thus, the reactions are usually not easy to control, which results in poor regioselectivity and the generation of multiple bromination products. To overcome these drawbacks, a green bromination reaction has been developed using inorganic bromine salts and peroxides, where the key step in these reactions is the generation of “Br + ” . Recently, Natarajan’s group and Muñiz’s group almost simultaneously achieved intramolecular C–H amination using n Bu 4 NBr and peroxides.…”

Recent progress in the oxidative bromination of arenes and heteroarenes

“…A green and efficient bromination method for the aromatic rings of aromatic amines, phenols and naphthalene by in situ oxidation of sodium bromide with hydrogen peroxide has been reported by the group of Cella 26 (Scheme 17). The brominated products were obtained in good to excellent yields (21 examples, 62–100%) with good selectivity under mild conditions.…”

Phosphotungstic acid impregnated niobium coated superparamagnetic iron oxide nanoparticles as recyclable catalyst for selective isomerization of terpenes

“…Boiling pearls were added to avoid liquid projection once magnetic stirring should be avoided in order to ensure the best dispersion of the superparamagnetic catalyst, but no conversion was observed under such a mild condition. In the second experiment, ultrasonic waves were employed as energy source for isomerization, [47][48][49] however no conversion was observed either in this attempt (entry 2, Table 3).…”