A 31P NMR Study of the Stability of Carboxyifosfamide and Carboxycyclophosphamide,Two Metabolites of Ifosfamide and Cyclophosphamide

Abstract

Ifosfamide (IF) and cyclophosphamide (CP) are two phosphorated anticancer agents used in the treatment of solid tumours. Several phosphorated metabolites, among them carboxyifosfamide (CXIF) and carboxycyclophosphamide (CXCP), were detected and quantified by ³¹P NMR in urine from patients treated with IF or CP. In agreement with other authors [1], we observed a great inter-patient variability in the urinary excretion of CXIF in patients treated with IF [2]. This variability was attributed to a genetic polymorphism of aldehyde dehydrogenase, the enzyme responsible for the formation of CXCP or CXIF [1,3]. Since CXCP and CXIF are unstable, we thought that the inter-individual variability could also be due to a degradation during the storage of urine samples. A ³¹P NMR study of the stability of CXIF and CXCP in urine as a function of time, pH (7 and 5.5) and storage temperature (25°C, 8°C, ?20°C, ?80°C) demonstrated that (i) CXCP and CXIF are more stable at pH 7 than at pH 5.5, (ii) CXCP is more stable than CXIF at both pH, (iii) the degradation decreases with temperature but still occurs at ?20°C and even ?80°C. For an accurate quantification of these compounds, the storage of urine samples must be done at ?80°C immediately after collection and not exceed 1 month at pH 7 whereas, at pH 5.5, the assay must be carried out in the few days following the sampling. To identify the degradation products of CXCP and CXIF, the time course of hydrolysis (between pH 2 and 7) of these compounds was monitored by ³¹P NMR. The structure of each compound formed was determined by mass spectrometry and ¹H and ¹³C NMR after their isolation (except compound A too unstable to be isolated). The results are reported in the following schemes.     

The Synthesis and X-Ray Structural Studies of Bis(1,3,2-Dithiaphospholane)

Abstract

The title compound 1 [³¹P NMR (CD₃CN): σ=36.7ppm] has been identified among the products of controlled hydrolysis of 2-dimethoxyphosphory1-1,3,2-dithiaphospholane (2) [1].     

31P NMR Determination of the Urinary Excretion of the Antitumor Drug Cyclophosphamide in Humans

Abstract

³¹P NMR was used to analyze urine from 4 patients treated with cyclophosphamide (CP) over 2 days. CP and most of its phosphorated metabolites (carboxyCP (CXCP), dechloroethylCP (DCCP), alcoCP, ketoCP and phosphoramide mustard (PM)) were assayed. Several other signals (10- 15) corresponding to unknown compounds were observed. Seven new compounds were identified: all were hydrolysis products of CP or its metabolites CXCP, DCCP and PM as reported below.     

Synthesis and characterization of novel (9H‐fluoren‐9‐ylamino) carbonylaminomethylphosphonic acid

The new α‐aminophosphonic acids are synthesized, reacting (9H‐fluoren‐9‐yl)urea with formaldehyde and phosphorus trichloride. (9H‐Fluoren‐9‐yl)urea was prepared from spiro(fluoren‐9,4′‐imidazolidine)‐2′,5′‐dione by alkaline hydrolysis with Ba(OH)₂. The structure of the title compounds was proved by means of IR, ¹H, ¹³C, and ³¹P NMR spectroscopy. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:719–722, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20500     

Kinetics of the acid and alkaline hydrolysis of Monofluorophosphite

The kinetics of the acid and alkaline hydrolysis of monoflorophosphorous acid has been studied by P-31 NMR and static pH titration over a wide temperature range. The acid catalyzed hydrolysis has a rate constant at 25°C equal to 0.35 dm³ mol^?1 s^?1 and an activation energy of 53 kJ while the alkaline hydrolysis has a rate constant of 4.6 dm³ mol^?1 s^?1 and an activation energy of 42 kJ. When the hydrogen in this compound is replaced by either fluorine or a hydroxyl group, the rates of reaction decrease by two orders of magnitude. © 1994 John Wiley & Sons, Inc.     

Towards the versatile DFT and MP2 computational schemes for 31P NMR chemical shifts taking into account relativistic corrections

The main factors affecting the accuracy and computational cost of the calculation of ³¹P NMR chemical shifts in the representative series of organophosphorous compounds are examined at the density functional theory (DFT) and second‐order Møller–Plesset perturbation theory (MP2) levels. At the DFT level, the best functionals for the calculation of ³¹P NMR chemical shifts are those of Keal and Tozer, KT2 and KT3. Both at the DFT and MP2 levels, the most reliable basis sets are those of Jensen, pcS‐2 or larger, and those of Pople, 6‐311G(d,p) or larger. The reliable basis sets of Dunning's family are those of at least penta‐zeta quality that precludes their practical consideration. An encouraging finding is that basically, the locally dense basis set approach resulting in a dramatic decrease in computational cost is justified in the calculation of ³¹P NMR chemical shifts within the 1–2‐ppm error. Relativistic corrections to ³¹P NMR absolute shielding constants are of major importance reaching about 20–30 ppm (ca 7%) improving (not worsening!) the agreement of calculation with experiment. Further better agreement with the experiment by 1–2 ppm can be obtained by taking into account solvent effects within the integral equation formalism polarizable continuum model solvation scheme. We recommend the GIAO‐DFT‐KT2/pcS‐3//pcS‐2 scheme with relativistic corrections and solvent effects taken into account as the most versatile computational scheme for the calculation of ³¹P NMR chemical shifts characterized by a mean absolute error of ca 9 ppm in the range of 550 ppm. Copyright © 2014 John Wiley & Sons, Ltd.     

New Lignans from the Aerial Parts of Rudbeckia laciniata

Three new furofuran lignans, (+)‐4,4′‐O‐diangeloylpinoresinol ( 1 ), (+)‐4,4′‐O‐diangeloylmedioresinol ( 2 ), and (+)‐4,4′‐O‐diangeloylsyringaresinol ( 3 ), together with the known compound (+)‐syringaresinol, were isolated from the MeOH extract of Rudbeckia laciniata. The structure elucidation of these compounds were based on 1D‐ and 2D‐NMR, and HR‐ESI‐MS data. The additional structural evidence was obtained from alkaline hydrolysis of the compounds.     

Characterization of active phosphorus surface sites at synthetic carbonate-free fluorapatite using single-pulse 1H, 31P, and 31P CP MAS NMR

The chemically active phosphorus surface sites defined as PO(x), PO(x)H, and PO(x)H2, where x = 1, 2, or 3, and the bulk phosphorus groups of PO4(3-) at synthetic carbonate-free fluorapatite (Ca5(PO4)3F) have been studied by means of single-pulse 1H,31P, and 31P CP MAS NMR. The changes in composition and relative amounts of each surface species are evaluated as a function of pH. By combining spectra from single-pulse 1H and 31P MAS NMR and data from 31P CP MAS NMR experiments at varying contact times in the range 0.2-3.0 ms, it has been possible to distinguish between resonance lines in the NMR spectra originating from active surface sites and bulk phosphorus groups and also to assign the peaks in the NMR spectra to the specific phosphorus species. In the 31P CP MAS NMR experiments, the spinning frequency was set to 4.2 kHz; in the single-pulse 1H MAS NMR experiments, the spinning frequency was 10 kHz. The 31P CP MAS NMR spectrum of fluorapatite at pH 5.9 showed one dominating resonance line at 2.9 ppm assigned to originate from PO4(3-) groups and two weaker shoulder peaks at 5.4 and 0.8 ppm which were assigned to the unprotonated PO(x) (PO, PO2-, and PO3(2-)) and protonated PO(x)H (PO2H and PO3H-) surface sites. At pH 12.7, the intensity of the peak representing unprotonated PO(x) surface sites has increased 1.7% relative to the bulk peak, while the intensity of the peaks of the protonated species PO(x)H have decreased 1.4% relative to the bulk peak. At pH 3.5, a resonance peak at -4.5 ppm has appeared in the 31P CP MAS NMR spectrum assigned to the surface species PO(x)H2 (PO3H2). The results from the 1H MAS and 31P CP MAS NMR measurements indicated that H+, OH-, and physisorbed H2O at the surface were released during the drying process at 200 degrees C.     

Synthesis and NMR Characterization of Two Novel Anthracene-Derived BIS-Aminophosphonates. Basic Hydrolysis of Some Aminophosphonate Derivatives

Abstract

The synthesis of two novel bis-aminophosphonates bearing anthracene rings – bis[N- methyl(diethoxyphosphonyl)-1-(9-anthryl)]benzidine (3) and 4,4′-bis[N-methyl(diethoxy-phosphonyl)-1-(9-anthryl)]diaminodiphenylmethane (4) – via the Kabachnik–Fields reaction is reported. The compounds have been characterized by elemental analysis, TLC, IR, NMR (¹H, ¹³C, ³¹P) and fluorescent spectra. The reaction leads to a mixture of the two possible forms (meso and racemic), with predominant formation of one of the diastereomers. The recrystallized compounds 3 and 4 consist of only one diastereomer. A racemization at the chiral centers and a cleavage of the C-P bond are observed in the alkaline hydrolysis of the new compound 4 and three previously described aminophosphonate derivatives 5–7.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Theoretical Study of the Alkaline Hydrolysis of Tricyclic Carbapenem

Alkaline hydrolysis is a good test to evaluate the properties of β‐lactam compounds and derivatives. In this work, a RHF/6‐31+G*//RHF/6‐31+G* theoretical study of the mechanism controlling the alkaline hydrolysis of sanfetrinem was conducted. The geometric properties of this compound are consistent with an intrinsic reactivity similar to that of other β‐lactams including penicillins and cephalosporins. Also, similarly to cephalosporins, the MeO group provides an alternative route for the hydrolysis mechanism.     

An investigation of the stability of the phosphate ester bond in D-pantothenic acid 4′-phosphate

The hydrolysis of the phosphate ester bond in D-pantothenic acid 4-phosphate in strongly acid (9 and 6 N HCl), weakly acid, weakly alkaline, and strongly alkaline (5 N KOH) aqueous media has been studied. In strongly acid and strongly alkaline media the phosphate ester bond of (I) breaks down completely in 3 and 2.5 h, respectively. The rate of hydrolysis at pH values between 1.3 and 11 remains constantly low but almost doubles in the presence of lanthanum salts at pH 8–9 and in the presence of lithium salts at pH 4 and a molar ratio of (I):Me⁺=1:1.Institute of Biochemistry Academy of Sciences of the Belorussian SSR, Grodno. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 262–265, March–April, 1987.     

Poly(bismethylene hydroquinone) (PBHQ). I. Synthesis and characterization

Poly(bismethylene hydroquinone) (PBHQ) has been synthesized. Fourier transform infrared, ¹³C solid-state CP/MAS NMR and elemental analysis provide strong evidence of two methylene bridges per hydroquinone molecule. The polymer was (1) air oxidized using ammonia and (2) chemically oxidized using bromine/KOH. The initial structure and oxidation process was studied by comparison of the unoxidized and oxidized polymers using Fourier transform infrared, elemental analysis, and ¹³C solid-state CP/MAS NMR.     

Phytoecdysteroids of plants of the genus Silene. XVII. Ecdysterone 22,25-di-O-benzoate from Silene scabrifolia

The new phytoecdysteroid ecdysterone 22,25-di-O-benzoate (IV) has been isolated from the epigeal organs ofSilene scabrifolia Kom. The alkaline hydrolysis of (IV) gave ecdysterone 25-O-benzoate and ecdysterone (I). Details of the IR, UV, mass, PMR, and¹³C NMR spectra of compound (IV) are given.     

Utility of the Pfitzinger Reaction in the Synthesis of Novel Quinoline Derivatives and Related Heterocycles

2‐(2‐Amino‐3,5‐dinitrophenyl)‐2‐oxoacetic acid ( 2 ) was obtained from hydrolysis of 5,7‐dinitroisatin ( 1 ) in alkaline media. A novel quinoxaline derivative ( 3 ) was synthesized from the reaction of the same compound ( 1 ) with o‐phenylenediamine. Reacting 2 with ethyl 3‐oxo‐3‐phenylpropanoate yields 6,8‐dinitro‐2‐phenylquinoline‐3,4‐dicarboxylic acid ( 4 ). Then, 4 was converted into new quinoline‐diacylchloride, quinoline‐ester, quinoline‐dicarboxamide, pyridazine, and pyrroledione derivatives ( 5 , 6a , 6b , 6c , 6d , 7a , 7b , 7c , 7d , 8 , 9 , 10a , 10b , 10c , 10d , 11a , 11b , 12 ) with SOCl₂, alcohols, amines, and hydrazines, respectively. The structures of synthesized compounds were clarified by ¹H NMR, ¹³C NMR, IR, mass and elemental analysis methods.     

Mononuclear Schiff base boron halides: synthesis, characterization, and dealkylation of trimethyl phosphate

A series of mononuclear boron halides of the type LBX(2) [LH = N-phenyl-3,5-di-tert-butylsalicylaldimine, X = Cl (2), Br (3)] and LBX [LH2 = N-(2-hydroxyphenyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (7), Br (8); LH2 = N-(2-hydroxyethyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (9), Br (10); and LH2 = N-(3-hydroxypropyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (11), Br (12)] were synthesized from their borate precursors LB(OMe)2 (1) (LH = N-phenyl-3,5-di-tert-butylsalicylaldimine) and LB(OMe) [LH2 = N-(2-hydroxyphenyl)-3,5-di-tert-butylsalicylaldimine (4), N-(2-hydroxyethyl)-3,5-di-tert-butylsalicylaldimine (5), N-(3-hydroxypropyl)-3,5-di-tert-butylsalicylaldimine (6)]. The boron halide compounds were air and moisture sensitive, and upon hydrolysis, compound 7 resulted in the oxo-bridged compound 13 that contained two seven-membered boron heterocycles. The boron halide compounds dealkylated trimethyl phosphate in stoichiometric reactions to produce methyl halide and unidentified phosphate materials. Compounds 8 and 12 were found to be the most effective dealkylating agents. On reaction with tert-butyl diphenyl phosphinate, compound 8 produced a unique boron phosphinate compound LB(O)OPPh2 (14) containing a terminal phosphinate group. Compounds 1-14 were characterized by 1H, 13C, 11B, 31P NMR, IR, MS, EA, and MP. Compounds 5, 6, and 11-14 also were characterized by single-crystal X-ray diffraction.     

Enantiodifferentiation of acyclic phosphonium salts in chiral liquid crystalline solutions

The enantiodifferentiation of acyclic phosphonium salts bearing a stereogenic centre, whether on the phosphorus atom or on one of its substituents, was investigated by ²H–{¹H}, ¹³C–{¹H} and ³¹P–{¹H} NMR in chiral liquid crystals composed of a polypeptide dissolved in an organic solvent. For the first time, the enantiomers of P-chirogenic phosphorus compounds were discriminated in these anisotropic media, affording good to excellent separation of the signals, allowing the determination of their proportion. While ³¹P–{¹H} NMR spectra showed no chiral separation, ²H–{¹H} NMR was efficient in the enantiodifferentiation of an isotopically labelled compound. Better still, ³¹C–{¹H} NMR in chiral liquid crystal appears as a powerful method for the enantiodifferentiation of this class of compounds, since separations of the signal up to 0.8 ppm were observed. In this commercially available anisotropic medium, ²H and ¹³C NMR offers a new promising alternative method for the enantiodifferentiation of chiral phosphonium salts.     

Structural and solid state 31P NMR studies of the four-coordinate copper(I) complexes [Cu(PPh3)3X] and [Cu(PPh3)3(CH3CN)]X

The tris(triphenylphosphine)copper(I) complexes [(PPh3)3CuX] for X = Cl (1), Br (2), I (3), ClO4 (4), BF4 (5), [(PPh3)3CuCl].CH3CN (1a), [Cu(PPh3)3(CH3CN)]X for X = ClO4 (6), BF4 (7), and [Cu(PPh3)3(CH3CN)]X.CH3CN for X = SiF5 (8), PF6 (9) have been studied by solid state 31P CP/MAS NMR spectroscopy together with single crystal X-ray diffraction for compounds (6)-(9), the latter completing the availability of crystal structure data for the series. Compounds (1)-(5) form an isomorphous series in space group P3 (a approximately 19, c approximately 11 A) with three independent molecules in the unit cell, all disposed about 3-fold symmetry axes. Average values (with estimated standard deviations) for the P-Cu-P, P-Cu-X bond angles and Cu-P bond lengths in compounds (1)-(3) are 110.1(6) degrees, 108.8(6) degrees and 2.354(8)A and 115.2(6) degrees, 102.8(9) degrees and 2.306(9)A for compounds (4) and (5). For the acetonitrile solvated compound (1a), the corresponding parameters are 115(4) degrees, 103(3) degrees and 2.309(3)A. The solid state 31P CP/MAS NMR quadrupole distortion parameters, dnu Cu, for (1)-(3) and (1a) are all less than 1 x 10(9) Hz2, despite the changes in donor properties of the halide in (1)-(3), and the coordination geometry of the P3CuX core in (1a). Change of anion to ClO4- and BF4- in compounds (4) and (5) results in a significant increase of dnu Cu to 4.4-5.2 10(9) Hz2 and 5.2-6.0 x 10(9) Hz2, respectively. Compounds (6) and (7) crystallise as isomorphous [Cu(PPh3)3(CH3CN)]X salts in space group Pbca, (a approximately 17.6, b approximately 22.3, c approximately 24.2 A), while compounds (8) and (9) crystallize as isomorphous acetonitrile solvated salts [Cu(PPh3)3(CH3CN)]X.CH3CN in space group P1(a approximately 10.5, b approximately 13.0, c approximately 19.5 A, alpha approximately 104, beta approximately 104, gamma approximately 94 degrees). The P3CuN angular geometries in all four compounds are distorted from tetrahedral symmetry with average P-Cu-P, P-Cu-N angles and Cu-P bond lengths of 115(4) degrees, 103(4) degrees and 2.32(1)A, with dnu Cu ranging between 1.3 and 2.5 x 10(9) Hz2. The solid state 29Si CP/MAS NMR spectrum of the pentafluorosilicate anion in compound (8) is also reported, affording 1J(29Si, 19F) = 146 Hz.     

Phytoecdysteroids of plants of the genusSilene XII. 5α-Ecdysterone 22-O-benzoate fromSilene scabrifolia

The new phytoecdysteroid 5α-ecdysterone 22-O-benzoate (I), C₃₄H₄₈O₃, mp 262–274°C (methanol-water) [α] _D ²⁰ +45.8° (methanol), has been isolated from the epigeal organ ofSilene scarbiofolia Kom. The alkaline hydrolysis of (I) led to 5α-ecdysterone (II) and benzoic acid. The isomerization of ecdysterone (0.6% KHCO₃ in CH₃OH) has yielded (II). Details of the IR, mass, and NMR spectra of compound (I) are given.     

Über polystannane: II. I(t-Bu2Sn)4I,ein 1,4-difunktionelles tetrastannan

The compound I(t-Bu₂Sn)₄I has been synthesized by controlled cleavage of the related cyclotetrastannane (t-Bu₂Sn)₄ with iodine in toluene. Both compounds have been investigated by mass, NMR and vibrational spectra. I(t-Bu₂Sn)₄I: δ(¹¹⁹Sn_terminal) 67.7, δ(Sn_central) 17.4 ppm; ¹J(SnSn) 2199 (terminal-central) and 1575 (central-central), ²J(SnSn) 20 (terminal-central), ³J (SnSn) 307 Hz (terminal-terminal); ν(SnSn) 119, ν(SnI) 167 cm^?1. (t-Bu₂Sn)₄: δ(Sn) 87.4 ppm; ν(SnSn) 125 cm^?1. The crystal structure of I(t-Bu₂Sn)₄I has been determined (R = 0.071): bond lengths SnSn 289.5(1) (terminal-central) and 292.4(1) (central-central), SnI 275.3(1) pm. The conformation of the chain ISn₄I is all trans.     

Solid-state NMR and EXAFS spectroscopic characterization of polycrystalline copper(I) O,O'-dialkyldithiophosphate cluster compounds: Formation of copper(I) O,O'-diisobutyldithiophosphate compounds on the surface of synthetic chalcocite

A number of polycrystalline copper(I) O,O'-dialkyldithiophosphate cluster compounds with Cu4, Cu6, and Cu8 cores were synthesized and characterized by using extended X-ray absorption fine-structure (EXAFS) spectroscopy. The structural relationship of these compounds is discussed. The polycrystalline copper(I) O,O'-diisobutyldithiophosphate cluster compounds, [Cu8{S2P(OiBu)2}6(S)] and [Cu6{S2P(OiBu)2}6], were also characterized by using 31P CP/MAS NMR (CP = cross polarization, MAS = magic-angle spinning) and static 65Cu NMR spectroscopies (at different magnetic fields) and powder X-ray diffraction (XRD) analysis. Comparative analyses of the 31P chemical-shift tensor, and the 65Cu chemical shift and quadrupolar-splitting parameters, estimated from the experimental NMR spectra of the polycrystalline copper(I) cluster compounds, are presented. The adsorption mechanism of the potassium O,O'-diisobutyldithiophosphate collector, K[S2P(OiBu)2], at the surface of synthetic chalcocite (Cu2S) was studied by means of solid-state 31P CP/MAS NMR spectroscopy and scanning electron microscopy (SEM). 31P NMR resonance lines from collector-treated chalcocite surfaces were assigned to a mixture of [Cu8{S2P(OiBu)2}6(S)] and [Cu6{S2P(OiBu)2}6] compounds.