Carboxylic phosphonic acid groups

Surfactants which contain carboxylic acid ester or amide chains with terminal phosphonic acid groups are prepared from polyhydroxystearic acid or poly-caprolactone. Such reaction products are useful as dispersants, emulsifiers, and, in some cases, bactericides, disinfectants, and antiseptics see Sec. III.C.9 [69]. 

Sulfoxides without amino or carboxyl groups have also been resolved. Compound 3 was separated into enantiomers via salt formation between the phosphonic acid group and quinine . Separation of these diastereomeric salts was achieved by fractional crystallization from acetone. Upon passage through an acidic ion exchange column, each salt was converted to the free acid 3. Finally, the tetra-ammonium salt of each enantiomer of 3 was methylated with methyl iodide to give sulfoxide 4. The levorotatory enantiomer was shown to be completely optically pure by the use of chiral shift reagents and by comparison with a sample prepared by stereospecific synthesis (see Section II.B.l). The dextrorotatory enantiomer was found to be 70% optically pure. 

In choosing a SAM system for surface engineering, there are several options. Silane monolayers on hydroxylated surfaces are an option where transparent or nonconductive systems are needed. However, trichlorosilane compounds are moisture-sensitive and polymerize in solution. The resulting polymers contaminate the monolayer surface, which occasionally has to be cleaned mechanically. Carboxylic acids adsorb on metal oxide, eg, A1 03, AgO through acid—base interactions. These are not specific therefore, it would be impossible to adsorb a carboxylic acid selectively in the presence of, for example, a terminal phosphonic acid group. In many studies SAMs of thiolates on Au(lll) are the system of choice. 

Both the 2-deoxy-2-H- (146) [160] and 2-deoxy-2,3-didehydro- (147) [168] Neu5Ac analogues with a phosphonic acid group in place of the carboxyl group have been synthesised by Vasella and coworkers. Steps in the synthesis of the 2-deoxy-2,3-didehydro analogue 147 [168] are shown in Scheme 13. The initial step was the bromohydroxylation of protected 2-deoxy-2,3-didehydro Neu5Ac. 

CS12A Hydrophilic surface. Contains both carboxyl and phosphonic acid groups... 

Ionic groups include carboxylic, sulfonic, and (less frequently) phosphonic acid groups. The acidic groups may be at least partially neutralized with monovalent, divalent, or trivalent metal cations, e.g., Na, Zrf, AI. Ionic cross-Iirrking of immiscible polymers bearing acidic groups may be mediated by such metal cations or by low molecular weight dibasic molecules such as diamines. 

Phosphonylation of a Carboxylic Acid Polymer. The reaction of a water-soluble polycarboxylic acid with phosphorous acid is said to yield a polymer with hydroxybis(phosphonic acid) structures. These are effective scale-inhibiting agents for aqueous systems (119) but not known to have been commercialized. A similar reaction in a Chinese study is said to result in the replacement of carboxyl groups by phosphonic acid groups (120) to produce pol5uners with similar utility. 

Surfactants are prepared which contain carboxylic acid ester or amide chains and terminal acid groups selected from phosphoric acid, carboxymethyl, sulfuric acid, sulfonic acid, and phosphonic acid. These surfactants can be obtained by reaction of phosphoric acid or phosphorus pentoxide with polyhydroxystearic acid or polycaprolactone at 180-190°C under an inert gas. They are useful as polymerization catalysts and as dispersing agents for fuel, diesel, and paraffin oils [69]. 

A dispersant that can be used in drilling fluids, spacer fluids, cement slurries, completion fluids, and mixtures of drilling fluids and cement slurries controls the rheologic properties of and enhances the filtrate control in these fluids. The dispersant consists of polymers derived from monomeric residues, including low-molecular-weight olefins that may be sulfonated or phosphonated, unsaturated dicarboxylic acids, ethylenically unsaturated anhydrides, unsaturated aliphatic monocarboxylic acids, vinyl alcohols and diols, and sulfonated or phosphonated styrene. The sulfonic acid, phosphonic acid, and carboxylic acid groups on the polymers may be present in neutralized form as alkali metal or ammonium salts [192,193]. 

One method for preparing imidazolylstannanes is direct metalation followed by treatment with RjSnCl [21]. l-Methyl-2-tributylstannylimidazole, derived in such manner, was coupled with 3-bromobenzylphosphonate (26) to furnish heterobiaryl phosphonate 27 [22], Under the same reaction conditions, 4-bromobenzylphosphonate led to the adduct in 69% yield, whereas only 24% yield was obtained for 2-bromobenzylphosphonate. The low yield encountered for the ortho derivative may be attributed to the steric factors to which the Stille reaction has been reported to be sensitive [23]. Heterobiaryl phosphonates such as 27 are not only substrates for the Wadsworth-Homer-Emmons reaction, but also bioisosteric analogs of the carboxylic acid group. 

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