Mass spectrometry of 1,2,5-oxadiazole N-oxide derivatives: use of deuterated analogues in fragmentation pattern studies

this paper reported on the study of fragmentation pattern in mass spectrometry of 1,2,5-oxadiazole n-oxide derivatives involving deuterium-labeled analogues to identify some critical fragmentations. a neutral ch2o loss from 3-hydroxymethyl-n2-oxide-4-phenyl-1,2,5-oxadiazole was confirmed with the corresponding mono-deuterated analogue. an oh loss, involving the oxygen of n-oxide, via b-h and d-h rearrangement, was clearly revealed from 3-(4-methylpiperazine-1-ylmethyl)-n2 -oxide-4-phenyl-1,2,5-oxadiazole using the adequate tetra-deuterated analogue. n-oxide isomer and deoxygenated analogues were also used to confirm the participation of the oxide moiety in the fragmentation process.