Acenaphthene, bromination

Blanc reaction, 129, 146 Bromination, acenaphthene, 35 anisole, 37 anthracene, 38 benzotrifluoride, 40... 

To an ethereal solution of 154 g. (1.0 mole) of acenaphthene is added slowly an ethereal solution containing a molar equivalent (160 g.) of bromine. The ether is removed by distillation, and the residue is distilled to give a fraction of light-brown solid boiling at 327-332°/760 mm. or 204-209°/30 mm. Recrystallization from alcohol gives colorless plates, m.p. 52°. The yield is 40. ... 

N-Bromosucdnimide (NBS) is a highly specific brorninating agent. When this reagent is used, anthracene is brominated in the 9-position. N-Bromosuccinimide may also be used to brominate positions a to (1) a carbonyl group, (2) a triple bond, (3) an alkene (allylic position), and (4) aromatic rings (benzylic position). Other polynuclear hydrocarbons that have been brominated using NBS include naphthalene, phenanthrene, and acenaphthene. 

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