Oxime derivatives of the intermediary oncostatic metabolites of cyclophosphamide and ifosfamide: synthesis and deuterium labeling for applications to metabolite quantification.
There is ongoing interest in the selective, quantitative analysis of the cyclophosphamide metabolites 4-hydroxycyclophosphamide (2a) and aldophosphamide (3a) because these tautomers are generally believed to play a key role in oncostatic selectivity and metabolite transport. O-(2,3,4,5,6-Pentafluorobenzyl)hydroxylamine (C6F5CH2ONH2, 1 equiv) provided for the complete conversion (by 31P NMR, 60% reaction within 15 min at 20 degrees C) of 2a/3a (17 mM in H2O/CH3OH) to E/Z-aldophosphamide O-(2,3,4,5,6-pentafluorobenzyl)oxime [C6F5CH2ON = CHCH2CH2OP-(O)(NH2)N(CH2CH2Cl)2; E:Z = 54:46 (+/- 3% average deviation)]. Under these conditions, the oxime exhibited little (6%) decomposition over 3 weeks. Parallel studies showed that 4-hydroxyifosfamide/aldoifosfamide reacted completely to give the analogous aldoifosfamide oxime [C6F5CH2ON = CHCH2CH2OP(O)(NHCH2CH2Cl)2; E:Z = 52:48 (+/- 1% average deviation)] with 50% reaction within 15 min at 20 degrees C with no product decomposition over 3 weeks. In aqueous methanol and with 2 equiv C6F5CH2ONH2, clinically useful 4-hydroperoxycyclophosphamide (10 mM; tau 1/2 = 10 min, 37 degrees C) and its isomer 4-hydroperoxyifosfamide (10 mM; tau 1/2 = 25 min, 20 degrees C) underwent complete conversion to the corresponding aldehyde oximes. Each oxime was synthesized with deuterium in the chloroethyl moieties for use as internal standards in GC/MS applications.
Ludeman
S M
SM
Division of Pharmacology and Experimental Therapeutics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
Shulman-Roskes
E M
EM
Wong
K K
KK
Han
S Y
SY
Anderson
L W
LW
Strong
J M
JM
Colvin
O M
OM
D003520:Cyclophosphamide / Q000737:chemistry* / Q000378:metabolism; D003903:Deuterium; D008401:Gas Chromatography-Mass Spectrometry; D007069:Ifosfamide / Q000737:chemistry* / Q000378:metabolism; D007553:Isotope Labeling; D009682:Magnetic Resonance Spectroscopy; D010091:Oximes / Q000138:chemical synthesis* / Q000378:metabolism; D010759:Phosphorus Isotopes
D010091:Oximes; D010759:Phosphorus Isotopes; D003520:Cyclophosphamide; D003903:Deuterium; D007069:Ifosfamide