10159-53-2Relevant academic research and scientific papers
The partitioning of phosphoramide mustard and its aziridinium ions among alkylation and P-N bond hydrolysis reactions
Shulman-Roskes, Ellen M.,Noe, Dennis A.,Gamcsik, Michael P.,Marlow, Allison L.,Hilton, John,Hausheer, Frederick H.,Colvin, O. Michael,Ludeman, Susan M.
, p. 515 - 529 (1998)
NMR (1H and 31P) and HPLC techniques were used to study the partitioning of phosphoramide mustard (PM) and its aziridinium ions among alkylation and P-N bond hydrolysis reactions as a function of the concentration and strength of added nucleophiles at 37 °C and pH 7.4. With water as the nucleophile, bisalkylation accounted for only 10-13% of the product distribution given by PM. The remainder of the products resulted from P-N bond hydrolysis reactions. With 50 mM thiosulfate or 55-110 mM glutathione (GSH), bisalkylation by a strong nucleophile increased to 55- 76%. The rest of the PM was lost to either HOH alkylation or P-N bond hydrolysis reactions. Strong experimental and theoretical evidence was obtained to support the hypothesis that the P-N bond scission observed at neutral pH does not occur in the parent PM to produce nornitrogen mustard; rather it is an aziridinium ion derived from PM which undergoes P-N bond hydrolysis to give chloroethylaziridine. In every buffer studied (bis-Tris, lutidine, triethanolamine, and Tris), the decomposition of PM (with and without GSH) gave rise to 31P NMR signals which could not be attributed to products of HOH or GSH alkylation or P-N bond hydrolysis. The intensities of these unidentified signals were dependent on the concentration of buffer.
Design, synthesis and evaluation of targeted hypoxia-activated prodrugs applied to chondrosarcoma chemotherapy
Canitrot, Damien,Chezal, Jean-Michel,Galmier, Marie-Josephe,Gaumet, Vincent,Gerard, Yvain,Ghedira, Donia,Maubert, Elise,Miot-Noirault, Elisabeth,Peyrode, Caroline,Tarrit, Sebastien,Voissière, Aurélien,Weber, Valérie
, (2020)
The tumor microenvironment in chondrosarcoma (CHS), a chemo- and radio-resistant cancer provides unique hallmarks for developing a chondrosarcoma targeted drug‐delivery system. Tumor targeting could be achieved using a quaternary ammonium function (QA) as a ligand for aggrecan, the main high negative charged proteoglycan of the extracellular matrix of CHS, and a 2-nitroimidazole as trigger that enables hypoxia‐responsive drug release. In a previous work, ICF05016 was identified as efficient proteoglycan-targeting hypoxia-activated prodrug in a human extraskeletal myxoid chondrosarcoma model in mice and a first study of the structure-activity relationship of the QA function and the alkyl linker length was conducted. Here, we report the second part of the study, namely the modification of the nitro-aromatic trigger and the position of the proteoglycan-targeting ligand at the aromatic ring as well as the nature of the alkylating mustard. Synthetic approaches have been established to functionalize the 2-nitroimidazole ring at the N-1 and C-4 positions with a terminal tertiary alkyl amine, and to perform the phosphorylation step namely through the use of an amine borane complex, leading to phosphoramide and isophosphoramide mustards and also to a phosphoramide mustard bearing four 2-chloroethyl chains. In a preliminary study using a reductive chemical activation, QA-conjugates, except the 4-nitrobenzyl one, were showed to undergo efficient cleavage with release of the corresponding mustard. However N,N,N-trimethylpropylaminium tethered to the N-1 or C-4 positions of the imidazole seemed to hamper the enzymatic reduction of the prodrugs and all tested compounds featured moderate selectivity toward hypoxic cells, likely not sufficient for application as hypoxia-activated prodrugs.
Improving nature's enzyme active site with genetically encoded unnatural amino acids
Jackson, Jennifer C.,Duffy, Sean P.,Hess, Kenneth R.,Mehl, Ryan A.
, p. 11124 - 11127 (2006)
The ability to site-specifically incorporate a diverse set of unnatural amino acids (>30) into proteins and quickly add new structures of interest has recently changed our approach to protein use and study. One important question yet unaddressed with unnatural amino acids (UAAs) is whether they can improve the activity of an enzyme beyond that available from the natural 20 amino acids. Herein, we report the >30-fold improvement of prodrug activator nitroreductase activity with an UAA over that of the native active site and a >2.3-fold improvement over the best possible natural amino acid. Because immense structural and electrostatic diversity at a single location can be sampled very quickly, UAAs can be implemented to improve enzyme active sites and tune a site to multiple substrates.
Nitrobenzyl-based photosensitive phosphoramide mustards: Synthesis and photochemical properties of potential prodrugs for cancer therapy
Reinhard, Robert,Schmidt, Brigitte F.
, p. 2434 - 2441 (2007/10/03)
Several nitrobenzyl-based photosensitive phosphoramide mustards were synthesized. The nitrobenzyl moiety was structurally varied to find the most promising prodrug candidates in respect to photorelease and activity of the alkylating species. The synthesis of these compounds proved to be applicable even in regard to compounds with additional functionalization. The target molecules 13a,b to 14 exhibited the expected red shift in their absorption spectra maximum compared to the parent nitrobenzyl moiety. As seen by UV and 31P NMR spectroscopy, the phosphoramide mustard was quickly liberated upon irradiation with mercury arc lamps. Assaying the structurally different prodrugs on their alkylating activity showed that compounds 13b and 14, derived from secondary benzyl alcohols, are promising prodrug candidates. Their water solubility and the possibility of attaching macromolecules are encouraging vis-a-vis future investigations on their in vitro cytotoxicity.
Synthesis, Activation, and Cytotoxicity of Aldophosphamide Analogues
Borch, Richard F.,Valente, Ronald R.
, p. 3052 - 3058 (2007/10/02)
A series of perhydrooxazine analogues of aldophosphamide has been prepared, and their 31P NMR kinetics and in vitro cytotoxicity have been evaluated.These compounds were developed on the basis of the idea that ring opening and tautomerization to an enamine intermediate might provide a mechanistic alternative to the β-elimination reaction for release of phosphoramide mustard.The 4,4,6-trimethyltetrahydro-1,3-oxazine moiety was selected on the basis of its rapid rate of iminium ion generation and relatively slow rate of hydrolysis.These analogues underwent phosphorodiamidate release by three distinct mechanisms: hydrolysis to aldophosphamide and subsequent β-elimination; cyclization to produce the 4-hydroxycyclophosphamides, which release phosphorodiamidate by ring opening and elimination; and tautomerization to the enamine with rapid expulsion of phosphorodiamidate.Kinetic studies demonstrated that hydrolysis to the aldehyde contributed minimally to the overall activation process and that the enamine pathway represented the major route of activation.For those analogues that could undergo cyclization this pathway competed effectively with enamine release, and these analogues were essentially equivalent to their 4-hydroxycyclophosphamide counterparts in cytotoxicity.A series of tetra-N-substituted phosphorodiamidates that cannot undergo cyclization was prepared to explore the effects of cyclization on the cytotoxicity of these analogues.The tetrakis(chloroethyl)phosphorodiamidates were highly potent in vitro against both cyclophosphamide-sensitive and -resistant L1210 and P388 cell lines, and one of these analogues had significant antitumor activity against L1210 leukemia in vivo.These results demonstrate that the enamine mechanism provides a viable pathway for delivery of phosphorodiamidates and that this approach can be used to deliver phosphorodiamidates that are non-cross-resistant in cyclophosphamide-resistant cell lines.
Aldophosphamide Acetal Diacetate and Structural Analogues: Synthesis and Cytotoxicity Studies
Wang, Yuqiang,Farquhar, David
, p. 197 - 203 (2007/10/02)
The synthesis of aldophosphamide acetal diacetate and a number of structural analogues is described.These compounds are designed to undergo biotransformation to the corresponding aldehydes in the presence of carboxylate esterases, enzymes that are ubiquitous in mammalian tissue.Several of these aldehydes can theoretically exist in pseudoequilibrium with the 4-hydroxyoxazaphosphorine tautomers; others lack this capability.The half-lives of the acetals in 0.05 M phosphate buffer, pH 7.4, at 37 deg C ranged from 1 to 2 days.In the presence of 2 unit equiv of porcine liver carboxylate esterase, all of the compounds were hydrolyzed with half-lives of less than 1 min.Although closely structurally related, the compounds exhibited a wide range of cytotoxicities to L1210 murine leukemia cells in vitro.
NMR Spectroscopic Studies of Intermediary Metabolites of Cyclophosphamide. A Comprehensive Kinetic Analysis of the Interconversion of cis- and trans-4-Hydroxycyclophosphamide with Aldophosphamide and the Concomitant Partitioning of Aldophosphamide between Irreversible Fragmentation ...
Zon, Gerald,Ludeman, Susan Marie,Brandt, Joan A.,Boyd, Victoria L.,Oezkan, Gunay,et al.
, p. 466 - 485 (2007/10/02)
Multinuclear (31P, 13C, 2H, and 1H) Fourier-transform NMR spectroscopy, with and without isotopically enriched materials, was used to identify and quantify, as a function of time, the following intermediary (short-lived) metabolites of the anticancer prodrug cyclophosphamide (1, Scheme I): cis-4-hydroxycyclophosphamide (cis-2), its trans isomer (trans-2), aldophosphamide (3), and its aldehyde-hydrate (5).Under a standard set of reaction conditions (1 M 2,6-dimethylpyridine buffer, pH 7.4, 37 deg C), the stereospecific deoxygenation of synthetic cis-4-hydroperoxycyclophosphamide (cis-12, 20 mM) with 4 equiv of sodium thiosulfate (Na2S2O3) afforded, after ca.20 min, a "pseudoequilibrium" distribution of cis-2, 3, 5, and trans-2, i.e., the relative proportions of these reactants (57:4:9:30, respectively) remained constant during their continual disappearance.NMR absorption signals indicative of "iminophosphamide" (8) and enol 6 were not detected ( "3" trans-2, as well as the rate constant (k3) for the irreversible fragmentation of 3.The values of k3 at pH 6.3, 7.4, and 7.8 were equal to 0.030 +/- 0.004, 0.090 +/- 0.008, and 0.169 +/- 0.006 min-1, respectively.Replacement of the HC(O)CH2 moiety in 3 with HC(O)CD2 led to a primary kinetic isotope effect (kH/kD = 5.6 +/- 0.4) for k3.The apparent half-lives (τ*1/2) for cis-2, "3", and trans-2 under the standard reaction conditions, at "pseudoequilibrium" (constant ratio of cis-2/"3"/trans-2), were each equal to ca.38 min, which is considerably shorter than the widely cited colorimetrically derived half-lives reported by earlier investigators.The values of τ*1/2 for cis-2, "3", and trans-2 were affected by pH in the same manner as that found for k3 but were relatively insensitive to the presence of either K(+), Na(+), Ca(2+), or Mg(2+).The presence of certain primary amines led to marked decreases in τ*1/2 and, in some cases, the formation of acyclic adducts of aldehyde 3.The relatively stable adduct formed from 3 and tris(hydroxymethyl)aminomethane (Tris) at pH 7.4 and 37 deg C gave rise to a 31P NMR signal that other investigators have mistakenly ascribed to 2. 31P NMR spectroscopy was also used to examine, in considerable detail, the manifold effects of N-acetyl-L-cysteine upon the chemistry of 2, "3", and 4, which featured the formation of a mixture of diastereomeric, acyclic ...
