Some commonly used 3-substituted, 4-substituted and 3,4,5-substituted pyridines were examinedusing DFT to predict the nucleophilicity behavior based on four different methods known in the literature.HOMO-LUMO energy calculations were done using DFT/B3LYP/6-311G+(d,p) level of theory. To establishthe most suitable nucleophilicity scale for all the ranges of pyridines covered herein, either Hammett substituentconstant (σ) or experimental nucleophilicity values were computed. On the basis of this study, some new4-substituted pyridines with enhanced nucleophilicity have been proposed. Nucleophilic behaviour of a fewpredicted molecules was found to be better than that of 4- pyrrolidino pyridine.
