A- phosphonic acid

A phosphonic acid can be esterified with CH2N2 in 88-100% yield. 

For monoprotection of a phosphonic acid NCCH2CH2OH, CI3CCN, 74-93% yield. ... 

A phosphonic acid was monoesterified with trichloroethanol, CCI3CN in Pyr at 100°. ... 

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. ... 

Figure 2.5 Direct synthesis of a phosphonic acid from white phosphorus.

Preparation of a-hydroxy-p-methylbenzylphosphonous acid — Preparation of a phosphonous acid from red phosphorus in aqueous medium23... 

Another approach toward the preparation of analogues of natural amino acids has been reported using the salt of a phosphonous acid with an aldehyde and a substituted urea in acetyl chloride as a solvent/ facilitator.350 This approach provides analogues that bear a single acidic hydrogen at the "acid site," although the attached alkyl group at phosphorus renders the species sterically less like the natural compounds. 

Mitsubishi have reported several processes based on Ru-catalyzed hydrogenation of anhydrides and acids. Succinic anhydride can be converted into mixtures of 1,4-butane-diol and y-butyrolactone using [Ru(acac)3]/trioctylphosphine and an activator (often a phosphonic acid) [97]. Relatively high temperatures are required ( 200°C) for this reaction. The lactone can be prepared selectively under the appropriate reaction conditions, and a process has been developed for isolating the products and recycling the ruthenium catalyst [98-100]. 

The phenylphosphonic acid 197 reacts with 5 equiv. of AgC104 to deliver the 1,2-oxa-phosphol-3-ene-2-oxide 198 in an 80% total yield of the Z- and E-isomers (Scheme 15.63) [127]. For related reactions, see also [128]. With a phosphonic acid and Hg(OAc)2, the mercurated intermediate, a 4-acetoxymercury l,2-oxaphosphol-3-ene and the corresponding chloride after ligand exchange were isolated [129]. 

Figure 41. Synthesis of a phosphonic acid containing poly(arylene ether) derived from a phenolphthalein-based bisphenol. ...

Layered metal IV phosphonates are widely used, particularly zirconium phosphonates, because their synthesis is versatile and their structural arrangement may be tailored to applications. Zirconium phosphonates are usually prepared by heating an aqueous solution of a metal IV salt (e.g., ZrOCl2) with a phosphonic acid at 60-80 °C synthesis in the presence of HP permits one to increase significantly the crystallinity of the final products. 

Zirconium phosphonates are solid materials typically synthesized in amorphous forms under aqueous conditions by the reaction of a soluble salt of a tetravalent metal and a phosphonic acid or an organophosphoric acid ... 

In many examples, it is not necessary to prepare the phosphorane. Instead, the dicarbonyl compound is heated with a trialkyl or triaryl ester of phosphorus acid or, less commonly, with a diester of a phosphonous acid (RP(OH)2, where R is an organic group). For example, when the thioester 301 is heated with dipropyl ethylphosphonite the 2-substituted carbapenem 302 is produced in 80% yield (Equation 32) <1997CPB1439>. This general method has been used to prepare 2-sulfide-substituted 1/3-methylcarbapenems <2000CPB126, 2001SC587> and O-protected 2-hydroxymethyl derivatives < 1999JA11261 >. 

The third question in 3D MESA - the dimension of the smallest pieces that can self-assemble - motivated experiments with metallic, polyhedral, 10- xm-sized plates [ref. 63]. The fabrication of 10- xm-sized polyhedra is difficult, so these experiments examined the self-assembly of flat plates, which were easily obtained at this scale. Photolithography, electrodeposition, and electron beam evaporation provided a convenient way to form plates having surfaces whose properties could be modified selectively. The surfaces of these plates consisted of either gold or chromium. Treatment with a long-chained alkanethiol formed a hydrophobic SAM on the gold with a phosphonic acid-terminated thiol, a hydrophilic one. Similarly, a phosphonic acid-terminated thiol formed a hydro-phobic SAM on chromium (through coordination of the acid with surface Cr... 

Equimolar reactions of an aluminum alkyl with a phosphonic acid under room temperature or reflux conditions yields oligomers of the formula [RA103PR ] (n = 4, 6, 10) (equation 28). Tetrameric (n = 4) derivatives (37) are the... 

A related reaction that yields the same types of products as does the Michaelis-Arbuzov reaction begins with either a phosphinous acid or a monoester of a phosphonous acid. (The corresponding reaction may also be performed with a diester of phosphorous acid.) By treatment with an appropriate base, the conjugate base of the phosphorus-containing acid is generated that serves as the nucleophihc reagent for direct formation of the phosphonate or phosphine oxide product (or phosphonate product from a phosphorous acid diester). This procedure is commonly referred to as the Michaehs Becker reaction. ... 

The phosphonylated enzyme can undergo spontaneous reactivation via hydrolysis to yield free enzyme and a phosphonic acid, with an associated pseudo-first-order rate constant, (the reactivator, water, is present in great excess). The spontaneous rate constant of reactivation, k, can be obtained from the relationship... 

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. 

The addition of 18-crown-6 to a mixture of a 4-nitrophenyl phosphoric triester (or of such an ester of a phosphonic acid) with alkoxide NaOR in ROH causes a catalytic deceleration in the solvolysis, whereas for the analogous thiophosphoryl compound a... 

Not many publications report performance data with BAM s membranes. The only publication we are aware of is by Stone et al., which also discusses the possibility of introducing a phosphonic acid functionality [98]. Figure 27.55 shows the performance data from this source. 

Fosfomydn Tromethamine. Fosphomycin trometha-mine (Monurol) is a phosphonic acid epoxide derivative that was initially isolated from fermentations of Streptomyces spp. The structure of the drug is shown below. Making the tromelhuminc salt greatly expanded the therapeutic utility of this antibucleriul because water solubility increased enough to allow oral administration. 

Condensation of an activated form of the nucleoside with a phosphonic acid [107] ... 

Vasella, A., and Wyler, R., Synthesis of a phosphonic acid analogue of 7V-acetyl-2,3-didehydro-2-deoxyneuraminic acid, an inhibitor of Vibrio cholerae sialidase, Helv. Chim. Acta, 74, 451, 1991. 

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