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An Expedited, Regiospecific para-Bromination of Activated ArylsDudley, Kathryn E 01 April 2017 (has links)
Electrophilic Aromatic Substitution (EAS) is one of the most frequently used aryl substitution methods. Aside from the fact that most EAS reactions require an acid and an oxidizer to proceed, the reactions involving activated aryls typically produce a mixture of ortho- and para- products as well as an ortho-/para- disubstituted product. Regiospecificity in aromatic substitution is key in the production of many compounds in a variety of disciplines. Since EAS is one of the most often used substitution methods, it is extremely important to develop an efficient method for regiospecific substitutions. Previous research developed a method of ortho-substitution by using hydrocarbon media, a less hazardous, greener medium, which was modified to develop a method of p-iodination (bromination), but with extensive time periods. The research presented here not only reveals an expedient, rapid method for regiospecific p-bromination, but also does so without the need for an acid or an oxidizer. The conditions for p-bromination involve the use of acetone (sometimes with cyclohexane) and NBS resulting in GC yields of p-brominated product approaching 100% in a cost and time efficient manner without the concerns of hazardous materials or byproducts like Br2 or HBr. The reaction mechanism is briefly examined as well.
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