Letter: steric effects in electrospray-tandem mass spectrometry of 11betanitrates of estrane series.
The fragmentation of [M+Na](+) ions produced from steroid 11beta-nitrates during electrospray/ionization (ESI) was studied by using ion trap MS/MS technique. The [M+Na](+) ions eliminate NO(2) and HNO(3) for epimers bearing 9beta and 9alpha substituents, respectively. As the main fragmentation pathways are determined mainly by the configuration at C-9 and alternative fragmentation does not practically occur, this offers the possibility for the determination of the configuration at chiral C-9 centre in the estrane 11beta-nitrate series by ESI mass spectrometry.
V I
VI
Kadentsev
A O
AO
Chizhov
O S
OS
Chizhov
O N
ON
Krupinova
V M
VM
Rzheznikov
L E
LE
Golubovskaya