Related Experiment Video
Updated: Jun 21, 2025

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Halogenated Phenylpyridines Possessing Chemo-Selectivity for Diverse Molecular Architectures
Nathan J Weeks1, Lynsey K Geray1, Mikhail B Lachapelle1
1Department of Chemistry and Chemistry Research Center, Laboratories for Advanced Materials, United States Air Force Academy, Colorado Springs, Colorado 80840, United States.
Abstract:
Pentafluoropyridine was used as a molecular building block for the installation of aryl bromides, affording a series of multisubstituted halogenated arenes. This operationally simplistic methodology offers precise regioselectivity, ease of scalability, and high purity. 19F Nuclear magnetic resonance (NMR) served as a key diagnostic tool for structural characterization, given the sensitivity with various aryl bromine substitutions on the fluorinated pyridine ring. Furthermore, molecular modeling simulations offered insight into this new class of halogenated phenylpyridines and their unique electronic and reactive properties. This study also demonstrates examples of efficient chemo-selectivity upon either metal-catalyzed aryl-aryl coupling or nucleophilic aromatic substitution of the aryl bromide or fluorinated pyridine scaffold, respectively. A diverse pool of polyarylene structures with high degree of complexity, functionalized linear polymers, and controlled network architectures were achieved from this simple methodology.
Related Concept Videos
ortho–para-Directing Deactivators: Halogens
Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
Reactions at the Benzylic Position: Halogenation
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.

