35691-25-9Relevant academic research and scientific papers
Kinetics and mechanism of the anilinolyses of aryl dimethyl, methyl phenyl and diphenyl phosphinates
Dey, Nilay Kumar,Kim, Chan Kyung,Lee, Hai Whang
supporting information; experimental part, p. 717 - 724 (2011/04/16)
The reactions of Z-aryl dimethyl (1), methyl phenyl (2), and diphenyl (3) phosphinates with X-anilines in dimethyl sulfoxide at 60.0 °C are studied kinetically. Kinetic results yield the primary normal deuterium kinetic isotope effects (DKIEs) involving deuterated aniline (XC6H4ND 2) nucleophiles, kH/kD = 1.03-1.17, 1.15-1.29, and 1.24-1.51, and the cross-interaction constants (CICs), ρXZ = 0.37, 0.34, and 0.65 for 1, 2, and 3, respectively. The steric effects of the ligands (R1 and R2) on reaction rates play a role, but are relatively much smaller compared to other phosphinate systems. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed on the basis of the CICs positive signs. The dominant frontside nucleophilic attack through a hydrogen-bonded, four-center-type transition state is proposed on the basis of primary normal DKIEs and large magnitudes of the CICs for 2 and 3, while both frontside and backside attack are proposed on the basis of relatively small primary normal DKIEs for 1.
Catalysis of the ethanolysis of aryl methyl phenyl phosphinate esters by alkali metal ions: Transition state structures for uncatalyzed and metal ion-catalyzed reactions
Onyido, Ikenna,Albright, Kendall,Buncel, Erwin
, p. 1468 - 1475 (2007/10/03)
This paper reports on a spectrophotometric kinetic study of the effects of the alkali metal ions Li+ and K+ on the ethanolysis of the aryl methyl phenyl phosphinate esters 3a-f in anhydrous ethanol at 25°C. Rate data obtained in the absence and presence of complexing agents afford the second-order rate constants for the reaction of free ethoxide (kEtO-) and metal ion-ethoxide ion pairs (kMOEt). The sequence k EtO- MOEt is established for all the substrates, contrary to the generally observed reactivity order in nucleophilic substitution processes. The quantities δGip, δGts and ΔGcat, which quantify the observed alkali metal ion effect in terms of transition state stabilization through chelation of the metal ion, give the order δGts > δGip for Li+ and K+. Hammett plots show significantly better correlation of rates with σ and σo substituent constants than with σ-, yielding moderately large Ρ(Ρo) values that are consistent with a stepwise mechanism in which formation of a pentacoordinate (phosphorane) intermediate is the rate-limiting step. The range of the values of the selectivity parameter, Ρn (= Ρ/Ρeq), 1.3 1.6, obtained for the uncatalyzed and alkali metal ion catalyzed reactions indicates that there is no significant perturbation of the transition state (TS) structure upon chelation of the metal ions. This finding is relevant to the mechanism of enzymatic phosphoryl transfer involving metal ion co-factors. The present results enable one to compare structural effects for nucleophilic reactions of several series of organophosphorus substrates. It is shown that the order of reactivity of the substrates: 4-nitrophenyl dimethyl phosphinate (2) > 3a > 4-nitrophenyl diphenyl phosphinate (1) is determined mainly by the steric effects of the alkyl/aryl substituents around the central P atom in the TS of the reaction. The Royal Society of Chemistry 2005.
Novel organophosphorus derivatives of indazoles and use thereof as medicinal products
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Page/Page column 12, (2008/06/13)
The present invention relates in particular to novel chemical compounds, particularly to novel organophosphorus derivatives of indazoles, to the compositions containing them, and to the use thereof as medicinal products for treating cancers.
Enzymatic resolution of chiral phosphinate esters
Li, Yingchun,Aubert, Sarah D.,Maes, Eugene G.,Raushel, Frank M.
, p. 8888 - 8889 (2007/10/03)
The bacterial phosphotriesterase has been shown to catalyze the stereoselective hydrolysis of phosphinate esters. The wild-type enzyme preferentially hydrolyzes the SP-enantiomers of methyl phenyl p-X-phenylphosphinate esters by 3 orders of mag
Correlation of 31P nuclear magnetic resonance chemical shifts in aryl phosphinates with Hammett substituent constants: Inductive versus resonance interactions and relevance to p? - d? bonding
Dunn, E. J.,Purdon, J. G.,Bannard, R. A. B.,Albright, K.,Buncel, E.
, p. 3137 - 3143 (2007/10/02)
Substituent-induced chemical shifts and coupling constants in the 31P, 13C, and 1H nuclear magnetic resonance spectra of meta- and para-substituted phenyl dimethylphosphinates (1), methylphenylphosphinates (2), and diphenylphosphinates (3) have been deter
PHOSPHORORGANISCHE VERBINDUNGEN 103. Die ozonolytische Desulfurierung von Thiophosphorylverbindungen: P=S -> P=O
Horner, L.,Flemming, H. W.
, p. 245 - 252 (2007/10/02)
The sulfur atom in thiophosphorylgroups P=S is exchanged by oxygen with retention of configuration according to (1) and (2) as a result of an interaction of the P=S groups with ozone (Table 1 and 2).In dithiophosphinicacidesters only the thionosulfur is easily replaced by oxygen using ozone.The absolute configuration of the enantiomeric methyl-phenyl-phosphinicacid-p-nitrophenylesters 7 an 8 is controlled on the basis of the reaction circle (4).Serine enzymes are blocked by the phosphinicacidesters 7 and 8 by a rate factor of about 60 faster than by the corresponding thionophosphinicacidesters 5 and 6.The phosphinicacidesters 7 (and 8) have a high O-selectivity in competing reactions (7:n-BuOH:n-BuNH2 = 1:1:1) in contrast to the thionophosphinicacidesters 5 (and 6) with no selectivity (ester:amide = 4:6).
