THEORETICAL INTERPRETATIONS OF SOME EXPERIMENTAL-OBSERVATIONS IN REACTIONS OF TRIAZOLOPYRIDINES AND THEIR QUATERNARY-SALTS

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