Hydroxyphosphonic acids

Figure 2.7 Use of red phosphorus for direct formation of a 1-hydroxyphosphonous acid.

Of course, the use of tris(trimethylsilyl) phosphite213 214 provides facile access to the free a-hydroxyphosphonic acids. These silyl reagents have been used for the preparation of a wide range of a-substituted phosphonates and -phosphonic acids, starting with ketene,215 a-ketophosphonates,216 ketoesters,217 218 and a,P-unsaturated carbonyl compounds,207/219-221 as well as simple aldehydes and ketones.205 210/219 224 Their use for the preparation of compounds of significant biological interest has been reviewed.125... 

The reduction of yff-ketoesters to aldols is one of the most important applications of Ru(II)-BlNAP catalysts [7]. As a special bonus, the chirally labile C2 stereogenic center can be exploited in a dynamic kinetic resolution such that racemic reactants yield only one of the four conceivable stereoisomers in high diastereomeric and enantiomeric excess. This strategy has been extended to the reduction of -ketophosphonates 10. The 3-hydroxyphosphonic acids 7 which are accessible by this route constitute promising starting materials for the synthesis of peptide analog and antibiotics [8]. 

Styrene-furfural and acetylated styrene-furfural copolymers on phosphorylation afford phosphonic acid (SFP) and hydroxyphosphonic acid (SFAP) cation-exchange resins, respectively. The equilibrium studies reveal that both resins have a high affinity for hydrogen and divalent ions. The values of the separation factor... 

For example, two reports of preparation of such species from elemental (red) phosphorus have been noted. The direct preparation of 1-hydroxyphosphonous acids, albeit in moderate yield, is accomphshed by the treatment of elemental phosphorus with aldehydes in aqueous basic medium (equation 12). Using polar aprotic solvents, the double direct addition of elemental phosphoms to arylalkenes proceeds to form phosphinous acids in better yields. Further, acid chloride derivatives are available also by the controlled reaction of elemental phosphoms with chloroalkanes. ... 

It has been observed that the reaction of methyl 2,3-di-0-benzyl-4,6-benzyli-dene-a(p)-D-glucopyranoside with triethyl phosphite and trimethylsilyl triflu-oro-methanesulfonate leads unexpectively to seven-membered phostone (394). Removal of protecting groups from the phostone is also reported (Figure 68). The simple transformation of carbohydrate-derived y-hydroxyphosphonic acids (395) into the corresponding phostones (396) using standard acylation conditions has been described (Scheme 97). 

Manufacture of hydroxyphosphonic acids from compounds with C=0 groups and phosphorous acid... 

Corey s phosphonamide route to olefins,3 When treated with 1 equivalent of n-butyllithium under nitrogen the reagent forms the a-lithio derivative (2), which reacts with a ketone (or aldehyde) to give a /3-hydroxyphosphonic acid bisamide (3) in yield of 90-98%. The adducts are uniformly nicely crystalline substances which, when refluxed in benzene or toluene in the presence of Woelm silica gel, undergo... 

The phosphonamide route has some advantages over the Wittig reaction. The reagents are readily prepared and potentially cheaper. The products are readily isolated (separation from triphenylphosphine oxide is sometimes troublesome). The intermediate /3-hydroxyphosphonic acid amides are readily purified. There is more opportunity to control the geometry and position of the double bond. 

Hydroxyphenyl sulfone. See 4,4 -Dihydroxydiphenyl sulfone 4-Hydroxyphenyl sulfonic acid. See p-Phenol sulfonic acid Hydroxyphosphonic acid Formula OP(OH)2CHOHCOOH... 

Hydroxyphosphonic acid Sodium nitrite corrosion inhibitor, fibers Oleamine acetate corrosion inhibitor, flocculation Stearamine acetate... 

Acylphosphonic acids and esters Monoacyl phosphites a-Hydroxyphosphonic acid esters... 

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