13C and 1H Nuclear Magnetic Shieldings and Electrical Effects of Ortho Substituents in Monosubstituted Pyridines.
Tetrahedron Letters (21):2575-2578
Since magnetic shieldings of 13c and 1h nuclei in the para-positions of monosubstituted benzines have been found to correlate well with hammett pn constants, the Bureau of Mines undertook the measurement of the shielding of the corresponding atoms, i.e., those in the 5- positions, in 2-substituted pyridines to investigate the electrical effects of ortho-substituents in monosubstituted pyridines.
Tetrahedron Letters, No. 21, PP. 2575-2578