Chiral separation and CD characterisation of enantiomeric cyclotriphosphazene derivatives.
The gem-disubstituted cyclotriphosphazene 1 reacted with piperazine (pip) to give the piperazine-bridged derivative 2, which is expected to exist in meso and racemic forms because the two PCl (pip) groups are stereogenic. The proton-decoupled (31)P NMR spectrum of 2 gave rise to two similar sets of ABX signals in a 1:1 ratio, consistent with formation of diastereoisomers. The meso and racemic forms of compound 2 were separated by column chromatography on silica gel and characterised by elemental analysis, mass spectrometry, (31)P NMR spectroscopy, and X-ray crystallography. Using HPLC with a chiral stationary phase, the racemic form of compound 2 was further separated into enantiomers, which were characterised by circular dichroism (CD) spectroscopy. This is the first report of the separation of enantiomers in the field of cyclophosphazene chemistry and hence the first CD spectra of derivatives in which the cyclophosphazene ring is at the chiral centre.
Bui
Tam T T
TT
Department of Pharmacy, Kings College (University of London), London, England.
Coles
Simon J
SJ
Davies
David B
DB
Drake
Alex F
AF
Eaton
Robert J
RJ
Hursthouse
Michael B
MB
Kiliç
Adem
A
Shaw
Robert A
RA
Yeşilot
Serkan
S
D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010753:Phosphoranes / Q000737:chemistry* / Q000302:isolation & purification; D010759:Phosphorus Isotopes; D000077489:Piperazine; D010879:Piperazines / Q000737:chemistry; D013237:Stereoisomerism
D010753:Phosphoranes; D010759:Phosphorus Isotopes; D010879:Piperazines; D000077489:Piperazine; C022601:hexachlorocyclotriphosphazene