Abstract
The conversion of 2,2′-bipyridine (bpy) to 4,4′-disubstituted derivatives is commonly achieved by a route involving preparation of the N,N′-dioxide and subsequent nitration with HNO3/H2SO4. The yields in the latter reaction are of the order of 50% and we now show that a competing ring oxidation process leads to the formation of 4-nitropicolinic acid. The solid state structure of the monohydrate of 4-nitropicolinic acid is reported, which exhibits a series of interesting packing motifs arising from hydrogen bonding networks.
Acknowledgements
We thank the Universities of Basel and Birmingham and the Swiss National Science Foundation for support of this work.