Inhibition of cholinesterases with cationic phosphonyl oximes highlights distinctive properties of the charged pyridine groups of quaternary oxime reactivators
摘要:
Oxime-induced reactivation of phosphonylated cholinesterases (ChEs) produces charged phosphonyl pyridine oxime intermediates (POXs) that are most potent organophosphate (OP) inhibitors of ChEs. To understand the role of cationic pyridine oxime leaving groups in the enhanced anti-ChE activity of POXs, the bimolecular rate constants for the inhibition (k(i)) of acetylcholinesterases (AChE) and butyrylcholinesterases (BChE), and the rate of decomposition (k(d)) of authentic O-alkyl methylphosphonyl pyridine oximes (AlkMeP-POXs) and N,N-dimethylamidophosphoryl pyridine oximes (EDMP-POXs), were studied. Stability ranking order in aqueous solutions correlated well with the electronic features and optimized geometries that were obtained by ab initio calculations at 6-31G** basis set level. AlkMeP-POXs of the 2-pyridine oxime series were found to be 4- to 8-fold more stable (t(1/2) = 0.7 to 1.5 min) than the homologous O,O-diethylphosphoryl (DEP) oxime. Results suggest that re-inhibition of enzyme activity by POX is less likely during the reactivation of DEP-ChEs (obtained by use of DEP-containing pesticides) by certain oximes, compared to nerve agent-inhibited ChEs. The greatest inhibition was observed for the O-cyclohexyl methylphosphonyl-2PAM derivative (4.0 x 10(9) M-1 min(-1); mouse AChE) and is 10-fold higher than the k(i) of cyclosarin. Increasing the size of the O-alkyl substituent of AlkMeP-POXs had only a small to moderate effect on the ki of ChEs, signifying a major role for the cationic pyridine oxime leaving group in the inhibition reaction. The shape of plots of log k(i) vs. pK(a) of the leaving groups for AlkMeP-PAMs and DEP-PANIs, could be used as a diagnostic tool to highlight and rationalize the unique properties of the cationic moiety of pyridine oxime reactivators. (C) 2003 Elsevier Science Inc. All rights reserved.
Andrews et al., Journal of the Chemical Society, 1952, p. 780,782
作者:Andrews et al.
DOI:——
日期:——
Boter,H.L.; Toet,H.J., Recueil des Travaux Chimiques des Pays-Bas, 1965, vol. 84, p. 1279 - 1283
作者:Boter,H.L.、Toet,H.J.
DOI:——
日期:——
Amino-aryl esters of acid phosphorus compounds
申请人:FITCH HOWARD M
公开号:US02759961A1
公开(公告)日:1956-08-21
A Convenient Method for the Phosphorylation of Phenols with Diethyl Cyanophosphonate
作者:Angel Guzmán、Eduardo Diaz
DOI:10.1080/00397919708005008
日期:1997.9
Abstract Phosphorylation of phenols with diethyl cyanophosphonate in methylene chloride solution at 0°C is an easy, rapid and good yielding reaction.
摘要 苯酚与氰基膦酸二乙酯在 0°C 二氯甲烷溶液中的磷酸化反应简单、快速且产率高。
Inhibition of cholinesterases with cationic phosphonyl oximes highlights distinctive properties of the charged pyridine groups of quaternary oxime reactivators
作者:Yacov Ashani、Apurba K. Bhattacharjee、Haim Leader、Ashima Saxena、Bhupendra P. Doctor
DOI:10.1016/s0006-2952(03)00204-1
日期:2003.7
Oxime-induced reactivation of phosphonylated cholinesterases (ChEs) produces charged phosphonyl pyridine oxime intermediates (POXs) that are most potent organophosphate (OP) inhibitors of ChEs. To understand the role of cationic pyridine oxime leaving groups in the enhanced anti-ChE activity of POXs, the bimolecular rate constants for the inhibition (k(i)) of acetylcholinesterases (AChE) and butyrylcholinesterases (BChE), and the rate of decomposition (k(d)) of authentic O-alkyl methylphosphonyl pyridine oximes (AlkMeP-POXs) and N,N-dimethylamidophosphoryl pyridine oximes (EDMP-POXs), were studied. Stability ranking order in aqueous solutions correlated well with the electronic features and optimized geometries that were obtained by ab initio calculations at 6-31G** basis set level. AlkMeP-POXs of the 2-pyridine oxime series were found to be 4- to 8-fold more stable (t(1/2) = 0.7 to 1.5 min) than the homologous O,O-diethylphosphoryl (DEP) oxime. Results suggest that re-inhibition of enzyme activity by POX is less likely during the reactivation of DEP-ChEs (obtained by use of DEP-containing pesticides) by certain oximes, compared to nerve agent-inhibited ChEs. The greatest inhibition was observed for the O-cyclohexyl methylphosphonyl-2PAM derivative (4.0 x 10(9) M-1 min(-1); mouse AChE) and is 10-fold higher than the k(i) of cyclosarin. Increasing the size of the O-alkyl substituent of AlkMeP-POXs had only a small to moderate effect on the ki of ChEs, signifying a major role for the cationic pyridine oxime leaving group in the inhibition reaction. The shape of plots of log k(i) vs. pK(a) of the leaving groups for AlkMeP-PAMs and DEP-PANIs, could be used as a diagnostic tool to highlight and rationalize the unique properties of the cationic moiety of pyridine oxime reactivators. (C) 2003 Elsevier Science Inc. All rights reserved.