The Kinetics of the Reaction of Isopropyl Methylphosphonofluoridate (Sarin) with Benzohydroxamic Acid<sup>1</sup>

Swidler, Ronald; Steinberg, George M.

doi:10.1021/ja01596a011

Cited by 46 publications

(24 citation statements)

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“…Later in 1956, Swidler and Steinberg [27] studied the kinetics of benzohydroxamic acid with phosphofluoridates and found that the stoichiometry and the rate of formation of fluoride and of acid were consistent with the Scheme 9 shown 12 above. Since, in mild basic solution this reaction competed with the hydrolysis of acyl halides, it appeared that the hydroxamic acids can, in effect, catalyze the decomposition of arylsulfonates and of DFP in aqueous solution.…”

Section: α-Nucleophilicty Of Hydroxamates In Watermentioning

confidence: 77%

From α-nucleophiles to functionalized aggregates: exploring the reactivity of hydroxamate ion towards esterolytic reactions in micelles

et al. 2015

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Owing to the rising threats of neurotoxic organophosphosphorus compounds, facile and efficient decontamination systems are required. Since the last few decades, the search for promising α-nucleophiles for straightforward and eco-friendly decontamination reactions using α-nucleophiles has been considerably boosted up. Among these, hydroxamic acids have been widely studied due to their potential α-nucleophilicity towards carbon and phosphorus based esters. This account summarizes our research on α-nucleophilicity of hydroxamate ions in water and micelles towards esterolytic reactions. Efforts of our group in the last few years have been collectively judged and compared with the crucial findings of researchers in the relevant field. The present article sheds light on the rich chemistry of the hydroxamate ion as a perfect candidate to degrade organophosphorus esters (i.e. nerve agents, pesticides and their simulants) in water, in micelles of conventional surfactants, and in functionalized micelles. The current report also provides an insight into the possible nature and mechanisms of these reactions. A brief account of the biological activities of hydroxamic acids that have recently spurred research in medicine against some fatal diseases has been included.

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Section: α-Nucleophilicty Of Hydroxamates In Watermentioning

confidence: 77%

From α-nucleophiles to functionalized aggregates: exploring the reactivity of hydroxamate ion towards esterolytic reactions in micelles

et al. 2015

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“…In keeping with Scheme 4 the apparent rate constants of the pseudofirst order k app , s 1 , are described by equation (1) including two parallel pathways: reactions of substrate S with the neutral [k HA , l/(mol s)] and anionic [k A , l/(mol s)] forms. a HA and a A determine k HA and k A K a1 a H + K a2 and a HA g ± ± (III XII 1 II Another fact supporting Scheme (4) is the kinetic behavior of amidoximes in the range of p 2 < pH << +2 that encompasses ~11 pH units.…”

Section: O-nucleophilic Features Of Amidoximesmentioning

confidence: 99%

O-nucleophilic features of amidoximes in acyl group transfer reactions

et al. 2004

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Analysis of kinetic behavior of isomeric Z-amidoximes and their Z-ions in reactions with 4-nitrophenyl-4-toluenesulfonate, diethylphosphate, and diethylphosphonate was performed in the framework of Bro \ nsted relationship. The reactivity of amidoximate anions with respect to the mentioned substrates is comparable to that of typical a-nucleophiles, oximate ions. The a-effect decreased with the growing basicity of amidoximate ions, and for compounds with pK a >12.0 it was totally lacking. The high nucleophilic activity of neutral amidoximes and their anionic forms was ascribed to the cyclic structure of the transition state involving two kinds of assistance: general acidic, and basic catalysis. A unique feature of amidoximes as a-nucleophiles consists in their ability to perform efficient cleavage of ecotoxic substrates in a wide pH range, from basic to acid media.Hydroxylamine oximes, amidoximes, and hydroxamic acids [19] occupy a special place in the series of typical a-nucleophiles for just among them efficient reactivators of cholinesterase has been found that are still required and whose preparation is attempted up till now [2,3,9]. The main attention nowadays in this field of research is attracted by the nature of the factors providing the abnormally high reactivity of a-nucleophiles [28]. Nonetheless, the O-nucleophilic characteristics of amidoximes in acyl transfer reactions were not subjected to detailed kinetic investigation. Amidoximes are oxime derivatives, but both their neutral and anionic form operate as acyl group acceptor [1014]. The kinetic behavior of amidoximes resembles in this respect rather that of hydroxylamine which also is capable to react with an acylating agent in neutral and anionic form [15,16] and is a unique a-nucleophile ensuring high reaction rates in basic, neutral, and acidic media. The hydroxylamine anion is a leader with respect to the O-nucleophilic reactivity in the series of known classes of the a-nucleophiles [15]. Aiming at development of systems for cleavage of ecotoxic substrates [9, 17] we measured in this study the reaction rates between the neutral and anionic forms of amidoximes and 4-nitrophenyl esters of 4-toluenesulfonic (I), diethylphosphoric (II), and diethylphosphonic (III) acids,* estimated the a-effect value, revealed the factors controlling the O-nucleophilic features of the amidoximes, and the place these a-nucleophiles occupy among the known supernucleophiles. 2 0H 6 2 12 2 , (W2 2 (W 2 3 3 (W2 2 12 (W2 2 ,, ,,,Isomerism and acid-base properties of amidoximes. The reactivity of typical a-nucleophiles, oximate ions, depends on the definite configuration (Z-or E-) that they take in the reaction with the acylating agents. As an example a Bro \ nsted relationship may be cited for reactions of substituted benzaldoximate ions with 4-nitrophenyl acetate (IV) and thioacetate: the E-isomers of * Esters II and III known under the names paraoxone and armin are typical cholinesterase inhibitors, belong to the class of stable ecotoxic substrates, and are only a little...

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“…Hackley et al and other workers (7)(8)(9)(10)(11)(12)(13) have found that the reaction of sarin with hydroxamic acids involves a nucleophilic'attack by the hydroximate ion as the rate determining step. The tautomeric form of the ion was proposed to be the reactive species in order to explain the very high activity of these compounds.…”

Section: Past Work Organophosphorous Compounds Reactionsmentioning

confidence: 99%

Molecular Catalysis and Interactions in Aqueous Solutions

Higuchi¹

1964

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The Kinetics of the Reaction of Isopropyl Methylphosphonofluoridate (Sarin) with Benzohydroxamic Acid¹

Cited by 46 publications

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From α-nucleophiles to functionalized aggregates: exploring the reactivity of hydroxamate ion towards esterolytic reactions in micelles

From α-nucleophiles to functionalized aggregates: exploring the reactivity of hydroxamate ion towards esterolytic reactions in micelles

O-nucleophilic features of amidoximes in acyl group transfer reactions

Molecular Catalysis and Interactions in Aqueous Solutions

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The Kinetics of the Reaction of Isopropyl Methylphosphonofluoridate (Sarin) with Benzohydroxamic Acid1

Cited by 46 publications

References 0 publications

From α-nucleophiles to functionalized aggregates: exploring the reactivity of hydroxamate ion towards esterolytic reactions in micelles

From α-nucleophiles to functionalized aggregates: exploring the reactivity of hydroxamate ion towards esterolytic reactions in micelles

O-nucleophilic features of amidoximes in acyl group transfer reactions

Molecular Catalysis and Interactions in Aqueous Solutions

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The Kinetics of the Reaction of Isopropyl Methylphosphonofluoridate (Sarin) with Benzohydroxamic Acid¹