NMR chemical shift prediction of pyridines

The chemical shifts of pyridines can be estimated using substituent chemical shifts (SCS) for the substituents in α (2/6), β (3/5) and γ (4) positions.
The SCS values used for the calculations are taken from [1].

Literature

[1] "Parameter set for the prediction of the ¹³C-NMR chemical shifts of sp²- and sp-hybridized carbon atoms in organic compounds"
Pretsch E, Fürst A, Robien W Anal. Chim. Acta 248 (1991) 415-428

R²=
R³=
R⁴=
R⁵=
R⁶=