ACETONE CHEMICAL-IONIZATION STUDIES .8. PYRIDINE-DERIVATIVES

Acetone chemical ionization mass spectra of pyridine and 23 isomeric a lkyl, dialkyl, amino, hydroxy, cyano and halo pyridines were studied, The formation of [M + H](+) ions and the adducts corresponding to [M 43](+) and [M + 59](+) ions is controlled by the proton affinity of t he substrate and the position of the substituent. The acetylation reac tion is less pronounced in 2-substituted pyridines due to steric facto rs, except in amino and hydroxypyridines where the acetylated ion is s tabilized through hydrogen bonding, Collision-induced dissociation (CI D) spectra of [M + 43](+) ions of isomeric amino and hydroxypyridines suggest acetylation occurs mainly at the ring nitrogen.