In　electrospray　ionization　tandem　mass　spectrometry　of　protonated　1-benzoylamines　(1benzoylpiperadine,　1-benzoylmorpholine,　and　1-benzoyl-4-methylpiperazine),　the　dominant　fragmentation　pathway　was　amide　bond　cleavage　to　form　benzoyl　cation　and　neutral　amine.　Meanwhile,　in　their　fragmentations,　an　interesting　loss　of　benzaldehyde　(106　Da)　was　observed　and　identified　to　derive　from　hydride　transfer　reaction　between　the　benzoyl　cation　and　amine.　A　stepwise　mechanism　for　loss　of　106　Da　(benzene　and　CO)　could　be　excluded　with　the　aid　of　deuterium　labeling　experiment.　Theoretical　calculations　indicated　that　hydride　transfers　from　amines　(piperadine,　morpholine,　and　1-methylpiperazine)　to　benzoyl　cation　were　thermodynamically　permitted,　and　1-methylpiperazine　was　the　best　hydride　donor　among　the　3　amines.　The　mass　spectrometric　experimental　results　were　consistent　with　the　computational　results.　The　relative　abundance　of　the　iminium　cation　(relative　to　the　benzoyl　cation)　in　the　fragmentation　of　protonated　1-benzoyl-4-methylpiperazine　was　higher　than　that　in　the　fragmentation　of　the　other　2　protonated　1-benzoylamines.　By　comparing　the　fragmentations　of　protonated　1-benzyl-4methylpiperazine　and　protonated　1-benzoyl-4-methylpiperazine　and　the　energetics　of　their　hydride　transfer　reactions,　this　study　revealed　that　benzoyl　cation　was　a　hydride　acceptor　in　the　gas　phase,　but　which　was　weaker　than　benzyl　cation.