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A theoretical study of the dithionite reduction of pyridinium salts
Author(s) -
Pop Emil,
Brewster Marcus E.,
Bodor Nicholas,
Huang MingJu
Publication year - 1993
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560480706
Subject(s) - chemistry , pyridinium , sodium dithionite , computational chemistry , pyridine , molecule , molecular orbital , chemical stability , hyperconjugation , medicinal chemistry , organic chemistry
The dithionite reduction of pyridinium salts results in the preferential formation of the 1,4‐dihydropyridines over the other possible (1,2 and 1,6) structural isomers. Theoretical studies performed in the framework of the AM1 molecular orbital approximation both on some simple, model molecules (dihydro‐1‐methyl‐3‐nicotinamide, 1 , and dihydro‐1‐methyl‐3‐methyl‐nicotinate, 2 ) and more complex derivatives (1‐methyl‐dihydro‐pyridine‐3‐carboxylates of estradiol, 3 , and azidothymidine, 4 ) supported thermodynamic product control. The increased relative thermodynamic stability of the 1,4‐dihydropyridine isomers is explained by favorable electronic interactions (homoaromaticity, hyperconjugation) governing in these derivatives. The calculated data support existing experimental evidence for product formation and isomer stability. © 1993 John Wiley & Sons, Inc.