Phosphonates hydrolysis

Scheme 5.3 Structures of (a) Irgafos 168, (b) Irgafos 168 phosphate and (c) Irgafos 168 phosphonate (hydrolysis product). After Scheirs et al. [150]. Reprinted with permission from J. Scheirs et al., Advances in Chemistry Series, 249, 359-374 (1996). Copyright (1996) American Chemical Society...

In a study designed to produce monoclonal antibodies which would catalyse the hydrolysis of phosphorus nerve agents, Moriarty et al. used a synthetic strategy involving a monocyclic phosphorane as hapten for the production of a monoclonal catalytic antibody based on the T.S. for phosphonate hydrolysis. These haptens (18 and 19), which are effective catalysts for the hydrolysis of Soman [Bu MeCHOPMe(0)F], were generated from the reaction of (15) with the protected 3(S) aminoalcohols (16 and 17). ... 

Phosphonic acid, H3PO3, often called just phosphorous acid , is prepared by the hydrolysis of phosphorus trichloride a stream of air containing phosphorus trichloride vapour is passed into ice-cold water, and crystals of the solid acid separate ... 

Tests in pure water, river water, and activated sludge showed that commercial ttiaryl phosphates and alkyl diphenyl phosphates undergo reasonably facile degradation by hydrolysis and biodegradation (163—165). The phosphonates can undergo biodegradation of the carbon-to-phosphoms bond by certain microorganisms (166,167). 

The reaction of phosphoms trichloride and water is highly exothermic and vigorous. Depending on the mole ratio of H2O/PCl, three different products can result from hydrolysis. If the ratio is greater than 3, phosphonic acid is produced ... 

All phosphoms oxides are obtained by direct oxidation of phosphoms, but only phosphoms(V) oxide is produced commercially. This is in part because of the stabiUty of phosphoms pentoxide and the tendency for the intermediate oxidation states to undergo disproportionation to mixtures. Besides the oxides mentioned above, other lower oxides of phosphoms can be formed but which are poorly understood. These are commonly termed lower oxides of phosphoms (LOOPs) and are mixtures of usually water-insoluble, yeUow-to-orange, and poorly characteri2ed polymers (58). LOOPs are often formed as a disproportionation by-product in a number of reactions, eg, in combustion of phosphoms with an inadequate air supply, in hydrolysis of a phosphoms trihahde with less than a stoichiometric amount of water, and in various reactions of phosphoms haUdes or phosphonic acid. LOOPs appear to have a backbone of phosphoms atoms having —OH, =0, and —H pendent groups and is often represented by an approximate formula, (P OH). LOOPs may either hydroly2e slowly, be pyrophoric, or pyroly2e rapidly and yield diphosphine-contaminated phosphine. LOOP can also decompose explosively in the presence of moisture and air near 150° C. 

Phosphonic acid is prepared by the dissolution of phosphoms(III) oxide or by the hydrolysis of phosphoms trichloride ... 

This reaction can be violent partiy because of the heat Hberated in the solvation of the hydrogen chloride. The hydrolysis can be moderated by adding PCl to a saturated solution of HCI Subsequentiy, the water and hydrogen chloride are boiled until the temperature reaches 180°C. On cooling, phosphonic acid crystallizes from the melt. 

Phosphonic (phosphorous) acid, produced by hydrolysis of PCl, is for the most part consumed captively. It has also been offered as a flaked product and a 70 wt % solution by Rhc ne-Poulenc. Phosphonic acid is a by-product from manufacturing carboxyHc acid chlorides and alkaH peroxides. Additional by-product phosphonic acid is recovered in the manufacture of phosphinic acid. 

The cyclic phosphonate ester analog of the cyclic transition state. Antibodies raised against this phosphonate ester act as enzymes they are catalysts that markedly accelerate the rate of ester hydrolysis. 

Salicylic acid was used for phosphite protection in the synthesis of glycosyl phosphites and phosphates. This derivative is very reactive and readily forms a phosphite upon treatment with an alcohol or a phosphonic acid upon aqueous hydrolysis. ... 

The ethoxycarbonyl group was developed for the protection of phosphonates. The derivative is prepared by reaction of tris(trimethylsilyl) phosphite with ethyl chloroformate and can be cleaved by hydrolysis of the ester followed by silyla-tion with bistrimethylsilylacetamide. ... 

Again, the recommended names (phosphonic acid and phosphonates) have found more general acceptance for organic derivatives such as RP03 , and purely inorganic salts are still usually called phosphites. The free acid is readily made by direct hydrolysis of PC l3 in cold CCI4 solution ... 

Addition of the alcohol 42 to a solution of BF3 Et20/TMSCN in DCM provided the nitrile 43 in 83% yield. Hydrolysis of nitrile 43 then furnished amide 44 in 85% yield. Demethylation of the methoxyindole 44 with BBra in DCM provided the hydroxyindole 45 in 80% yield. This was followed by alkylation of 45 with the bromide 46 under phase transfer conditions to provide the phosphonate ester 47 and subsequent cleavage of the methyl ester by TMS-I furnished trimethylsilyl phosphonic acid 48, which upon alcoholic workup afforded LY311727. 

Phosphonates are organic phosphates characterized by a C-P-O bond, which is much more resistant to hydrolysis than the polyphosphate bond (O-P-O) or the phosphate ester bond (C-O-P), making them suitable for many types of BW treatment formulation. Phosphonates were originally developed for the industrial and institutional (I I) cleaning market in the 1960s, but are commonly employed in a myriad of applications. 

There are many parallels between phosphates and sulfates of aliphatic alcohols. Both types of surfactants contain ester bonds undergoing hydrolysis in acid solutions. In that case the starting materials are received once more. By dry heating of the salts above a temperature of 140°C destruction will occur forming the corresponding alkenes and an inorganic acid salt. In the same way as sulfonic and sulfinic acids are formed by C-S bonds, C-P bonds lead to phosphonic and phosphinic acids. 

Hydrolysis of the RPOCl3 complex to phosphonic acid and new chloration of the achieved phosphonic acid to the dichloride. 

The phosphotriesterase from Pseudomonas diminuta was shown to catalyze the enantioselective hydrolysis of several racemic phosphates (21), the Sp isomer reacting faster than the Rp compound [65,66]. Further improvements using directed evolution were achieved by first carrying out a restricted alanine-scan [67] (i.e. at predetermined amino acid positions alanine was introduced). Whenever an effect on activity/ enantioselectivity was observed, the position was defined as a hot spot. Subsequently, randomization at several hot spots was performed, which led to the identification of several highly (S)- or (R)-selective mutants [66]. A similar procedure was applied to the generation of mutant phosphotriesterases as catalysts in the kinetic resolution of racemic phosphonates [68]. 

Recently, good yields of glyphosate have been reported after hydrolysis using tris-trimethylsilyl phosphite in a similar sequence with 48 to generate the disilyl phosphonate triester intermediate 50 (S3). 

Other interesting examples of proteases that exhibit promiscuous behavior are proline dipeptidase from Alteromonas sp. JD6.5, whose original activity is to cleave a dipeptide bond with a prolyl residue at the carboxy terminus [121, 122] and aminopeptidase P (AMPP) from E. coli, which is a prohne-specific peptidase that catalyzes the hydrolysis of N-terminal peptide bonds containing a proline residue [123, 124]. Both enzymes exhibit phosphotriesterase activity. This means that they are capable of catalyzing the reaction that does not exist in nature. It is of particular importance, since they can hydrolyze unnatural substrates - triesters of phosphoric acid and diesters of phosphonic acids - such as organophosphorus pesticides or organophosphoms warfare agents (Scheme 5.25) [125]. 

A kinetic study of the basic hydrolysis in a water/AOT/decane system has shown a change in the reactivity of p-nitrophenyl ethyl chloromethyl phosphonate above the percolation threshold. The applicability of the pseudophase model of micellar catalysis, below and above the percolation threshold, was also shown [285],... 

B. Reactions.—(/) Nucleophilic Attack at Phosphorus. A reinvestigation of the reaction between phosphorus trichloride and t-butylbenzene in the presence of aluminium chloride has shown that the product after hydrolysis is the substituted phosphinic acid (11), and not the expected phosphonic acid (12). Bis(A-alkylamino)phosphines have been reported to attack chlorodiphenyl phosphine with nitrogen, in the presence of a base, to give bis-(A-alkyl-A-diphenylphosphinoamino)phenylphosphines (13). In (13), the terminal phosphorus atoms are more reactive than the central one towards sulphur and towards alkyl halides. 

The enzyme FAAH was first identified in the 1980s [39], cloned in the 1990s [25] and more recently, the crystal structure [40] of FAAH bound to methyl arachidonyl phosphonate has been published. The FAAH enzyme has wide substrate specificity capable of catalysing the hydrolysis of a wide variety of... 

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