The electrochemical reduction of several 2,5- and 5,6- dihalonicotinic acids have been studied in dimethyl sulfoxide as well as in aqueous buffers of different pH. The polarographic half-wave potentials for the reduction of these compounds in both media are reported here. The compounds appear to reduce at the carboxyl group. The presence of halogen atoms on the pyridine ring facilitates reduction.
Shaikh, Ali U.; Dixon, Tappi A.; Battles, Lourie A.; and Setliff, Frank L.
"Electrochemistry of Dihalogenated Nicotonic Acids in Aqueous and Aprotic Media,"
Journal of the Arkansas Academy of Science: Vol. 40
, Article 20.
Available at: http://scholarworks.uark.edu/jaas/vol40/iss1/20