Phosphonates structure

Attempts have been made to incorporate functional groups into the phosphonates in zinc phosphonate structures. Zn(03P(CH2)2C02H) H20 was reacted with aromatic amines but no amide formation was observed. However, Zn(03P(CH2)2C0NHC6H5) could be synthesized directly from zinc nitrate, (2-carboxyethyl)phosphonic acid, and aniline in a one-step procedure.406... 

PECH did not react with potassium cyanate but reacted with equimolar potassium thiocyanate in DMF (90°Ci.16 h) to give the thiocyanated polymer (2g, IR, 2180 cm 1) in 53% of DS. Comparing the IR spectrum with those of model compounds, Me2CHCH2SCljl (2180 cm-1) and Me2CHCH2NCS (2200., 2125 cm-1), the isothiocyanate moieties are scarcely existed in the polymer 0. Since the -SCN is a protecting form of thiol likewise the -SCI, the polymer 20 are insolubilized with aqueous alkali presumably due to the S-S crosslinking (23.). Further, absorption at 2180 cm in 20 was completely disappeared treating it with two equivalents of triethyl phosphite at 90°C for 16 h in DMF probably due to the formation of phosphonate structure ( ,). ... 

Related to guanidinium sulfonates are analogous cation phosphonate structures which can adopt either pillared or zeotype structures. Recently novel tubular morphologies have also been discovered for both classes of compound which may have promise for improving porosity in these types of material. At present, like the guanidinium sulfonates, few phosphonates, are really porous and removal of the guest template generally leads to the collapse of the structures.15... 

The formation of keto-phosphonate structure within macromolecule leads to the removal of internal unsaturation. Triallyl cyanurate and ionizing irradiations [210] made a E-P block copolymer-PE blend thermally stable. Triallyl cyanurate increases the crosslinking density probably due to addition reactions between polymeric and allyl radicals produced by ionizing radiation. The addition of 2,2,4-trimethyl-l,2-di-hydroquinoline and bis[4(l-methyl-1-phenylethyl)pheny 1]-amine stabilized a PE-EPDM blend against heat [211]. Popov et al. [212] studied the ozone effect on PE-iPP blend. The oxidation rate was detected in relation to... 

Oligomers of phosphonate structure were formed in reaction and simultaneously transfer occurred as it could be expected for Arbusov rearrangement ... 

Kishi and coworkers noted the importance of the phosphonate structure in the synthesis of monensin, where a methyl phosphonate was used to maximize (Z)-alkene formation. These observations were expanded upon in the synthesis of rifamycin Several interesting Wittig reactions from this synthesis are presented in Table 14. 

Shibasaki s procedure found particular application in asymmetric carbonyl addition by use of dialkylphosphites (Scheme 6.108) [131]. Although the ee observed were rather moderate to good (55-90% ee), the a-hydroxy phosphonate structures... 

Many research groups have started with PPACK and produced inhibitors of a less peptidic nature (to improve in vivo stabihty), and/or with conformational restriction (to tackle the entropy loss problem), and/or with a variety of serine trap functionalities, for example, aldehydes, boronic acids, a-keto amides and acids, a-keto heterocycles, polyfluorinated ketones, and phosphonates. Structures of many of these are known in complex with thrombin but will not be reviewed here (see e.g., pubhca-tions of C.A. Kettner and coworkers). As well as lack of specificity, these potential drugs suffer from slow on-rates and have not progressed to the market. 

Imamura, M., and Hashimoto, H., Synthesis of novel CMP-NeuNAc analogues having a glycosyl phosphonate structure, Tetrahedron Lett., 37, 1451, 1996. 

Simultaneous dyeing and flame retardation of 100% polyester fabric has always been a commercially successful aim and while research has been undertaken in this area with reasonable levels of durability achieved, either in a dye bath or by thermosol process, potential commercial exploitation depends on the costs relative to the cost of using an inherently low flammable polyester. Currently in the UK, for example, Solvay (formerly Rhodia) market Amgard CU which is the same as the former Antiblaze IQ " for finishing polyester textiles based on the cyclic phosphonate structure where n=l ... 

There is currently no proof for the existence of dialkyl H-phosphonates in phosphite form in basic medium. Studies of the dialkyl H-phosphonate structure in a basic medium (e.g., amines) by H and NMR and IR spectroscopy have shown that dialkyl H-phosphonates exist entirely in their four-coordinate phosphonate form [19-22], An alkylation of the amine and not a deprotonation of dialkyl H-phosphonates occurs ... 

In the NMR spectrum of the methylammonium salt of the monomethyl ester of H-phosphonic add, the phosphorus signal appears at 4.55 ppm as a doublet of quartets with V(P,H) = 600 Hz indicating phosphonate structure. Kers et al. [23] confirm that in the reaction mixture of diethyl H-phosphonate and pyridine or pyridine with 2 equiv. of tertiary base (TEA), there were no signals that could be assigned to Iriethyl phosphite. The results obtained show that the basic activation in these reactions involves at the first step formation of the monoalkyl H-phosphonate anion [(R0)P(0)(H)0] , which further plays the key role in interactions where the phosphorus atom acts as a nucleophile. 

There is a growing need to develop new and efficient synthetic routes to macmillan-functionalized phosphonic structures that permit control of stereochemistry. Various metal complexes have been found to act as effective catalysts for the reaction, including titanium [197] and lanthanide [198] systems. A key objective in phosphotrans-fer chemistry is the development of metal-based catalysts for the phosphor-aldol (PA) reaction. These complexes mnst be (i) simple to prepare, (ii) inexpensive, (iii) tunable, (iv) compatible with air and water, (v) reusable, (vi) stereoselective. There are a number of PA catalysts that satisfy the above criteria [199]. It was shown that the chiral salcyan complexes of alnminnm are effective air- and water-tolerant enan-tioselective catalysts for hydrophosphonylation of carbonyls [200]. The initial step of the... 

In the presence of AICI3, ring opening (pathway B) occurs, resulting in the formation of a mixture of dimethyl ester of 2-hydroxyl-2-methyl-l-acetopropylphosphonic acid and l-hydroxyl-2-methyl-2-acetoisopropylphosphonic acid. NMR spectra showed signals at 23-26 ppm, which is characteristic for the phosphonate structure. 

The other type of metal salt is prepared via dealkylation of one or two alkyl substituents of the alkoxy groups of the dialkyl H-phosphonate. These salts retain their phosphonate structure since the immediate surrounding of the tetrahedral phosphorus atom remains unchanged. 

These metal salts retain the phosphonate structure of the starting dialkyl H-phosphonates, which is characterized by a four-coordinated phosphorus atom in the O3PH fragment. They can be prepared in one of the following methods ... 

The proton conductivity of such polymers was close to 10 Scm , and it was higher than that of suhbnated polymers. Although the phosphonated structure has advantage of increasing the proton conductivity in ion-containing polybenzimidazole, incorporation of DCP in these polymers decreases the solubihty in N-methyl-2-pyrrolidone (N-MP). 

PDHc El, phosphonate structural unit as moiety A was linked with an aryl or a heterocycle group as moiety B by a carboxylate ester bond to form 1-oxophos-phonic acid derivatives (Scheme 1.18). In order to find a lead compound with desired herbicidal activity, different structural unit Q was introduced into this phosphonate scaffold resulting a series of 1-oxophosphonic acid derivatives [68]. 

These results indicated that phenoxyacetoxy moiety and proper substitution at phenoxyacetoxy moiety were very important for post-emergence activity. Acceptable post-emergence herbicidal activity of alkylphosphonates lo should have a reasonable combination of both phosphonate structural unit and proper substituted phenoxyacetate moieties. Detail study on alkylphosphonates lA-IK can be found in Chap. 2. 

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