Mass spectral studies on synthetic analogues of organophosphorus toxin isolated from Ptychodiscus brevis

A series of structurally related organophosphorus oximes analogous to O,O-d ipropyl-(E)-2-(1-methyl-2-oxopropylidene)phosphorahydrazidothioate-(E)-oxim e, isolated from Ptychodiscus brevis, have been synthesised and subjected t o electron impact (EI) mass spectral studies, These studies, though aimed a t total identification of these compounds, resulted in certain interesting observations and hence are being reported. In order to confirm the observat ions under electron impact and to support the mechanism of fragmentation we have also performed tandem mass spectrometry experiments in some cases.