32586-82-6Relevant academic research and scientific papers
Radiolysis of Di- and Tri-methyl Phosphates in Oxygenated Aqueous Solution: a Model System for DNA Strand Breakage
Schuchmann, Man Nien,Sonntag, Clemens von
, p. 699 - 704 (1984)
In the radiolysis of aqueous solutions of trimethyl phosphate saturated with N2O-O2 the major products (G values in parentheses) are dimethyl hydrogen phosphate (6.4), formic acid (3.4), formaldehyde (1.7), hydrogen peroxyde (2.1), organic peroxide (0.5), and carbon monoxide (1.0).Oxygen is consumed (G 4.1).In the dimethyl phosphate (sodium salt) system the products and their G values are similar to those of the trimethyl phosphate system.Pulse radiolytic studies have shown that in trimethyl phosphate system the first formed peroxyl radicals react with each other to give a short lived tetraoxide (2k = 9 x 1E8 dm3 mol-1 s-1).This intermediate decays either by concerted mechanism or by fragmentation to form O2 and two oxyl radicals.Among other reactions these oxyl radicals undergo a 1,2-hydrogen shift, followed by a complex series of reactions.There are two processes that yield acids at longer reaction times.The faster process has been identified as the hydrolysis of formic dimethylphosphoric anhydride (k = 0.3 + 2.3 x 1E4 -> s-1).The slower process (k = 2 600 s-1) is only observed in basic solutions and has not yet been identified with certainity.The present findings are used as a model to assist in the interpretation of some aspects of DNA radiolysis.
Benzoyl methyl phosphates as efficient reagents in the one-pot tandem approach for the synthesis of 2-phenylbenzimidazoles in water
Hikawa, Hidemasa,Imani, Maki,Suzuki, Hideharu,Yokoyama, Yuusaku,Azumaya, Isao
, p. 3768 - 3773 (2014/01/06)
A novel and efficient method for the environmentally benign, catalyst- and auxiliary-free synthesis of 2-phenylbenzimidazoles in water is developed. Benzoyl methyl phosphates play important roles as biomimetic acylating agents for the one-pot tandem approach without additional catalysts.
Benzoyl methyl phosphate as an efficient reagent for the selective monobenzoylation of N-Bz-FTY720
Hikawa, Hidemasa,Hamada, Maiko,Yokoyama, Yuusaku,Azumaya, Isao
supporting information, p. 23131 - 23136 (2014/06/24)
A novel and efficient method for the selective monobenzoylation of N-Bz-FTY720 with benzoyl methyl phosphate (BMP) promoted by Zn(OAc)2 and Cs2CO3 was developed. Benzoyl methyl phosphate plays an important role as a biomimetic acylating agent for the monobenzoylation of 1,3-diols.
Demonstration of prominent Cu(ll)-promoted leaving group stabilization of the cleavage of a homologous set of phosphate Mono-, Di-, and triesters in methanol
Tony Liu,Neverov, Alexei A.,Maxwell, Christopher I.,Stan Brown
supporting information; experimental part, p. 3561 - 3573 (2010/05/01)
A series of phosphate mono-, di-, and triesters with a common leaving group (LG) (2′-(2-phenoxy)1, 10-phenanthroline) was prepared, and the kinetics of decomposition of their Cu(II) complexes was studied in methanol at 25°C under sspH-controlled conditions. The Cu(II) complexes of 2-[2′-phenanthrolyl]phenyl phosphate (Cu(ll):6), 2-[2′- phenanthrolyl]phenyl methyl phosphate (Cu(II):7), and 2-[2′-phenanthrolyl] phenyl dimethyl phosphate (Cu(II):8) are tightly bound, having dissociation constants Kd -7 M, with the Cu(II) being in contact with the departing phenoxide. The sspH/rate profile for cleavage of Cu(II): 6 has a low sspH plateau (k0 = 6.3 × 10-3 s-1), followed by a bell-shaped maximum (kcatmax= 14.7 ± 0.4 s -1) dependent on two ionizations with sspK a3 and sspKa 21 = 7.8 ± 0.1 and 11.8 ± 0.2. The sspH/rate profile for cleavage of Cu(ll):7 has a broad plateau from sspH 3 to sspH 10 followed by a descending wing at higher sspH with a gradient of -2. The s spH/rate profile for cleavage of Cu(ll):8 is sigmoidal with two plateaus (Zc1 = (2.0 ± 0.2) × 10-5S-1, k 2 = (1.2 ±0.2) × 10-6S-1), connected by an ionization with a sspKa of 6.03. Activation parameters are given for the reactions in the plateau regions: all three species show similar ΔH# terms of 21.4-21.6 kcal/mol, with major differences in the ΔS- terms, which vary from 18 to 2.3 to -7.4 cal/(mol-K) passing from the mono- to di- to triester. Detailed analyses of the kinetics indicate that the reactions involve spontaneous solvent-mediated cleavage of the Cu(ll)-coordinated phosphate dianion [Cu(ll):6b]° and phosphate diester monoanion [Cu(ll):7b]+ and, for the triester, complexes containing Cu(II) and Cu(II): -OCH 3 designated as [Cu(ll):8a]2+ and [Cu(ll):8b]+. Reactions where methoxide is the active nucleophile are not observed. Comparisons of the rates of the decomposition of these species at their sspH maxima in the neutral sspH region with the estimated rates of the background reactions indicate that leaving group assistance provided by the coordinated Cu(II) accelerates the cleavage of the phosphate mono-, di-, and triesters by 1014 to 1015, 1014, and 105. Detailed Hyperquad 2000 analysis of titration data indicates that phenoxide 9- is bound 23 kcal/mol stronger than the phosphate triester 8. It is the realization of part of this energy in the emerging products resulting from P-O(LG) cleavage that provides the driving force for the catalyzed reactions.
Dissociative solvolytic cleavage of methyl (ortho-Carboxymethyl)Aryl phosphate diesters mediated by Yb3+ in methanol gives a 10 12-fold rate acceleration attributable to leaving group assistance
Edwards, David R.,Neverov, Alexei A.,Brown, R. Stan
supporting information; experimental part, p. 368 - 377 (2009/06/28)
The Yb3+-catalyzed cleavage of a series of eight methyl aryl phosphates (2a-h) where the aryl groups all contain an ortho-methoxycarbonyl group was studied in acidic methanol from 1.34 ≤ spHs ≤ 3.34 at 25 °C. All substrates show saturation binding of the metal ion that is analyzed to provide a conditional binding constant (K)b for a 1:1 substrate/Yb3+ complex and catalytic rate constant (A cat) that varies between about 2 × 10-3 and 50 × 10-3 s-1 overthe range of substrates. Detailed analysis indicates that at very low c oncentration of Yb3+, 3 equiv of substrate are bound, and with increasing [Yb3+], the binding changes to a 1:1 complex which decomposes by a pathway independent of spHs over the range investigated. Control studies show that substrates without the o-methoxycarbonyl group still bind to the Yb 3+ with approximately the same strength as do the o-methoxycarbonyl containing substrates but have no observable reaction when bound. A Jaffe plot of the kcat vs substituent ?-values indicates that, during the catalyzed reactions of 2a-h, the phenoxy-O and C(O)OCH3 groups accommodate negative and positive charge respectively, the p phosphate and p c(o)OMe values being (1.84 ±0.11) and ( 0.85 ±0.14). For all these substrates, the final reaction products are dimethyl phosphate and the Yb3+ complex of the phenoxide. A study of the binding of the parent phenols to Yb3+ indicates that log(Kbind) = (0.84 ± 0.06)sspKa+ (3.4 ± 0.9), r2 = 0.9664 for phenols containing the o-methoxycarbonyl group; for those lacking that substituent log(Kb ind) = (0.96 ± 0.04)s spKa- (1.73 ± 0.4), (r2 = 0.99). For the catalyzed reacti on the βlg = -0.48, while the βeq = -0.95, leading to a Leffler parameter of α = 0.51. A mechanism is presented for the catalyzed reaction which is highly dissociative, having a transition state where the Yb3+ translocates during the cleavage reaction to assist the leaving group's departure with weak nucleophilic assistance by the solvent methanol. A comparison of the catalyzed rate of reaction with a computed rate of reaction attributable to solvent alone indicates that Yb3+ provides leaving group assistance on the order of 1012-fold, stabilizing the transition state for cleavage by some 16 kcal/mol.
Synthesis of (S)-isoprenoid thiodiphosphates as substrates and inhibitors
Phan,Poulter
, p. 6705 - 6710 (2007/10/03)
Thiolo thiophosphate analogues of isopentenyl diphosphate (IPP), dimethylallyl diphosphate (DMAPP), geranyl diphosphate (GPP), farnesyl diphosphate (FPP), and geranylgeranyl diphosphate (GGPP) were synthesized. Inorganic thiopyrophosphate (SPPi) was prepared from trimethyl phosphate in four steps. The tris(tetra-n-butylammonium) salt was then used to convert isopentenyl tosylate to (S)-isopentenyl thiodiphosphate (ISPP). (S)-Dimethylallyl (DMASPP), (S)-geranyl (GSPP), (S)-farnesyl (FSPP), and (S)-geranylgeranyl thiodiphosphate (GGSPP) were prepared from the corresponding bromides in a similar manner. ISPP and GSPP were substrates for avian farnesyl diphosphate synthase (FPPase). Incubation of the enzyme with ISPP and GPP gave FSPP, whereas incubation with IPP and GSPP gave FPP. GSPP was a substantially less reactive than GPP in the chain elongation reaction and was an excellent competitive inhibitor, KIGSPP=24.8 μM, of the enzyme. Thus, when ISPP and DMAPP were incubated with FPPase, GSPP accumulated and was only slowly converted to FSPP.
Phosphoric Amides. Part 8. The Effect of the Ethyleneimine Substituent on the Solvolytic Reactivity of Phosphate and Phosphoramidate Bonds
Davidowitz, Bette,Modro, Tomasz A.
, p. 303 - 306 (2007/10/02)
Rates and products of the base-catalysed hydrolysis of some amidoesters of phosphoric acid have been determined in the N,N-dimethyl derivative, the P-N bond is resistant, and the P-O bond deactivated towards hydrolysis, while in the N-methyl substrate, the reactivity of the ester link is similar to that in trimethyl phosphate.In the N-ethylene compound, both P-O and P-N bonds are strongly activated.The N-(β-chloroethyl) substrate reacts via fast, base-catalysed cyclization to the N-ethylene amidate.
