Phosphonates, activated

MA/EA/VA) (polymer is approx. 80% hydrolyzed maleic anhydride, 10% ethyl acrylate, 10% vinyl acrylate) has been available for many years and exhibits properties similar to those of PMA. It cannot operate at the same extremes of service, but is of lower cost and competes well with other technologies. It has better general dispersion properties than many polyacrylates and is less sensitive to soluble iron. It can often replace polyacrylates as a phosphonate activity enhancer. 

Annelatlon reactions. The ketenimine 1 acts chemically as a vinyl phosphonate activated by the cumulated imino group and is useful as an annelation reagent for the synthesis of heterocyclic compounds. As such it condenses with the sodium salt of salicylaldehyde (2) to afford the benzopyrane in 3 in 52% yield. Similarly, the pyrrolizine 5 is available from the sodium salt of 2-formylpyrrole in 51% yield. ... 

Phosphorylation methods that are used in the synthesis of GPIs are adopted from the weU-estabhshed protocols for the synthesis of oligonucleotides. The two commonly used methods are both based on phosphitylation that is followed by oxidation. Phosphitylation of an alcohol with H-phosphonates activated via transient formation of mixed anhydride with pivaloyl chloride followed by oxidation with iodine in wet pyridine is commonly used to prepare the phosphate salts (Scheme 12.3, introduction of the phosphoHpid phosphodiester). The reagents... 

Kaiser et al. have presented the development of a para-nitrophenol phosphonate activity-based probe (489) with structural similarities to the potent agrochemical paraoxon. The authors demonstrated that these probes labels distinguished serine hydrolases with the carbo)q lesterase... 

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). 

Antlblaze 19. Antiblaze 19 (Mobil), a flame retardant for polyester fibers (134), is a nontoxic mixture of cycHc phosphonate esters. Antiblaze 19 is 100% active, whereas Antiblaze 19T is a 93% active, low viscosity formulation for textile use. Both are miscible with water and are compatible with wetting agents, thickeners, buffers, and most disperse dye formulations. Antiblaze 19 or 19T can be diffused into 100% polyester fabrics by the Thermosol process for disperse dyeing and printing. This requires heating at 170—220°C for 30—60 s. 

The alkyl and alkoxy substituents of phosphate or phosphonate esters also affect the phosphorylating abiUty of the compound through steric and inductive effects. A satisfactory correlation has been developed between the quantitative measure of these effects, Tafts s O, and anticholinesterase activity as well as toxicity (33). Thus long-chain and highly branched alkyl and alkoxy groups attached to phosphoms promote high stabiUty and low biological activity. 

Much effort has been placed in the synthesis of compounds possessing a chiral center at the phosphoms atom, particularly three- and four-coordinate compounds such as tertiary phosphines, phosphine oxides, phosphonates, phosphinates, and phosphate esters (11). Some enantiomers are known to exhibit a variety of biological activities and are therefore of interest Oas agricultural chemicals, pharmaceuticals (qv), etc. Homochiral bisphosphines are commonly used in catalytic asymmetric syntheses providing good enantioselectivities (see also Nucleic acids). Excellent reviews of low coordinate (coordination numbers 1 and 2) phosphoms compounds are available (12). 

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

The cychc phosphonate of ( -HPMPA, [( -cHPMPA [106941-26-8], C H 2N50 P, 28] also is active against HSV-1 and HSV-2 infection in mice. Both (27) and (28) are reported to be efficacious against adenovims, vaccinia vims, as weU as variceUa-2oster vims infections (58). 

Earlier formulations contained mainly chlorine bleach, metasiUcates, triphosphate, and nonionic surfactants. Modem manufacturers have switched to more compHcated formulations with disiUcates, phosphates or citrate, phosphonates, polycarboxylates, nonionic surfactants, oxygen bleach, bleach activator, and enzymes. The replacement of metasiUcates by disilicates lowers pH from approximately 12 to 10.5, at 1 g ADD/L water. The combined effect of decreased pH, the absence of hypochlorite, and the trend toward lower wash temperatures has paved the way for the introduction of enzymes into ADDs. Most ADD brands in Europe are part of the new generation of ADD products with enzymes. The new formulations are described in the patent hterature (55—57). 

Napamezole (68) is a dihydroimidazole derivative with antidepressant activity probably as a result of its combined a 2 adrenergic receptor blockuig and serotonin uptake blocking proper ties It can be synthesized by Wittig olefination of p-tetralone (65) with diethyl (cyanomethyl) phosphonate (66) and base to give nitnle 67 Imidazoline construction on the latter was smoothly... 

The substrate scope is limited, as electron-withdrawing groups (X = p-N02 or p-CF3) on the aromatic substituent are not tolerated. However, this route does provide valuable intermediates to unnatural a-amino phosphonic acid analogues and the sulfimine can readily be oxidized to the corresponding sulfonamide, thereby providing an activated aziridine for further manipulation, or it can easily be removed by treatment with a Grignard reagent. 

NOTE This formula is designed for removing calcium and iron foulants. Use at 300 ppm in the boiler. This produces 37 ppm of active polymer for dispersancy and 18 ppm active phosphonate for threshold stabilization. 

There are several methods for preparing surface-active phosphonic acids and their derivatives. 

Because fatty alcohols can easily be converted to the corresponding chlorides or bromides, they are a useful starting material for surface-active phosphonic acid derivatives. A variety of n-alkoxymethylphosphonic acids possessing surface-active properties were synthesized from fatty alcohols having an even number of carbon atoms (Cl2-C18) [98] see Eqs. (34)-(36). 

By substituting n-butyldichlorophosphine for PC13 the butyl monoester of the a-hydroxyalkylphosphonic acid is formed. If there are 12 or more carbon atoms in the molecule the compound will be surface-active and still soluble in water. Alkali salts of the free phosphonic acids obtained by the reactions... 

The synthesis and surface-active properties of higher hydroxyalkanediphos-phonates are discussed in Ref. 67. Phosphorus-containing betaines as hydrolytically stable surfactants, free from alkali salt impurities, were prepared by a reaction of amidoamines and equimolar amounts of phosphonate esters with 1.5-2 eq of formaldehyde at 60-140°C in a polar solvent [72]. 

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