ChemInform Abstract: Theoretical Interpretations of Some Experimental Observations in Reactions of Triazolopyridines and Their Quaternary Salts

The site of alkylation of triazolopyridines ( 1 a ), ( 5 ), and ( 6 ) has been interpreted using semi-empirical and ab initio molecular orbital calculations. Attack by hydride on the methyl triazolopyridinium salt ( 3a ) has been shown to give the triazolylbutadiene ( 4a ), while the isomeric salt ( 2a ) is unaffected by nucleophiles. These observations are interpreted by consideration of the mechanisms of reaction, and calculation of appropriate energy levels.