Phosphonic acid/phosphonate

AUenic phosphonic acids, phosphonates and phosphine oxides can be easily prepared from propargylic alcohols and phosphinyl chloride (see Chapter 1). They readily react with both electrophilic reagents and nucleophilic reagents. 

Transition states of this tetrahedral nature have now been mimicked effectively by a range of stable analogues, including phosphonic acids, phosphonate esters, a-difluoroketones, and hydroxymethylene functional groups (Jacobs, 1991). Lerner s group elicited antibodies to a tetrahedral anionic phosphonate hapten [3] (Appendix entry 2.9)2 whilst Schultz s group isolated a protein with high affinity for p-nitrophenyl cholyl phosphate [4] (Fig. 4) (Appendix entry 3.2). 

Isocyanomethyl)phosphonate 97 is also a beneficial pronucleophile leading to optically active (l-aminoalkyl)phosphonic acids, phosphonic acid analogs of a-amino acids via tra s-5-alkyl-2-oxazoline-4-phosphonates 98 (E = PO(OPh)2, Sch. 25) [50]. ... 

The gold-catalyzed aldol reaction has been successfully applied to the asymmetric synthesis of (l-aminoalkyl)phosphonic acids, phosphonic analogs of a-amino acids (Scheme 2-57) [80, 81]. The reaction of (isocyanomethyl)phosphonates 65 with... 

There are several possibilities for phosphonate polyol synthesis by Mannich reactions, Arbuzov reactions and by alkoxylation of phosphonic acids. Phosphonate polyols proved to be very efbcient flame retardants in practice. An important quality of these phosphorus polyols is the stability over time of formulated polyols containing phosphonate and water as reactive blowing agent, without a significant loss of their reactivity. 

Another self assembled monolayer which has been applied to OFETs is based on phosphonic acids. Phosphonic acids attach to many metals and metal oxides, including alumina, and provide essentially the same passivation and surface energy engineering on that dielectric system [40]. 

As mentioned in Volume 13 of these Reports, 4-oxoazetidin-2-yl phosphonates and phosphinates (19) can be prepared by Arbusov-like reactions between P compounds and 4-acetoxyazetidin-2-one (20). Acid hydrolysis of (19) yields phosphono- and phosphino-aspartic acids (21) which can be converted into peptides with antibacterial activity. Diastereomeric mixtures of phosphono-dipeptides, which can be prepared from racemic dialkyl 1 -aminoalkylphosphonates, can be separated by ion-exchange chromatography. It appears that it is easier to synthesize phosphonodipeptides from these phosphonates as their P-dialkyl esters rather than as the free phosphonic acids. Phosphonic acid analogues of A-Cbz-alanine and -phenylalanine can be converted into ester and amide fluoridates, e.g., (22, R = OMe or NHCHMeg). These fluoridates are the most potent inhibitors of elastase and chymotrypsin yet reported and seem to mimic the natural substrates of these enzymes. ... 

Phosphonic acid, (nitrilotris (methylene)) tri-. See Am inotri methylene phosphonic acid Phosphonic acid, (nitrilotris (methylene)) tri-, pentasodium salt. See Pentasodium aminotrimethylene phosphonate Phosphonic acid, octadecyl ester. See Stearyl phosphate... 

Most organic phosphorus acids which have a P OH group have a strong band at 1040-910 cm probably involving the stretching of the P—0(H) bonds. This includes phosphinic acids, phosphonic acids, phosphonous acids, half esters of phosphonic acids, and acid salts of phosphonic acids. 

A pletliora of different SA systems have been reported in tire literature. Examples include organosilanes on hydroxylated surfaces, alkanetliiols on gold, silver, copper and platinum, dialkyl disulphides on gold, alcohols and amines on platinum and carboxyl acids on aluminium oxide and silver. Some examples and references can be found in [123]. More recently also phosphonic and phosphoric esters on aluminium oxides have been reported [124, 125]. Only a small selection out of tliis number of SA systems can be presented here and properties such as kinetics, tliennal, chemical and mechanical stability are briefly presented for alkanetliiols on gold as an example. 

More recently, alternative chemistries have been employed to coat oxide surfaces with SAMs. These have included carboxylic 1129, 1301, hydroxamic 11311, phosphonic 1124, 1321 and phosphoric acids 11331. Potential applications of SAMs on oxide surfaces range from protective coatings and adhesive layers to biosensors. 

Phosphonic acid, H3PO3, often called just phosphorous acid , is prepared by the hydrolysis of phosphorus trichloride a stream of air containing phosphorus trichloride vapour is passed into ice-cold water, and crystals of the solid acid separate ... 

Adducts from various quaternary salts have been isolated, in reactions with aldehydes, a-ketoaldehydes, dialkylacylphosphonates and dialkyl-phosphonates, isocyanates, isothiocyanates, and so forth (Scheme 15) (36). The ylid (11) resulting from removal of a Cj proton from 3.4-dimethyl-S-p-hydroxyethylthiazolium iodide by NEtj in DMF gives with phenylisothiocyanate the stable dipolar adduct (12) that has been identified by its NMR spectrum and reactional product, such as acid addition and thiazolidine obtention via NaBH4 reduction (Scheme 16) (35). It must be mentioned that the adduct issued from di-p-tolylcarbodiimide is separated in its halohydrogenated form. An alkaline treatment occasions an easy ring expansion into a 1,4-thiazine derivative (Scheme 17) (35). 

HP(0)(0H)2 Phosphonic acid HP(0)d Phosphonoyl-—PiOfOHj Phosphono- Phosphonate... 

HNCO isocyanic acid H2PHO3 phosphonic acid... 

Acryhc esters dimerize to give the 2-methylene glutaric acid esters catalyzed by tertiary organic phosphines (37) or organic phosphorous triamides, phosphonous diamides, or phosphinous amides (38). Yields of 75—80% dimer, together with 15—20% trimer, are obtained. Reaction conditions can be varied to obtain high yields of trimer, tetramer, and other polymers. 

MixedPhosphona.te Esters. Unsaturated, mixed phosphonate esters have been prepared from monoesters of 1,4-cyclohexanedimethanol and unsaturated dicarboxyhc acids. Eor example, maleic anhydride reacts with this diol to form the maleate, which is treated with benzenephosphonic acid to yield an unsaturated product. These esters have been used as flame-retardant additives for thermoplastic and thermosetting resias (97). 

Phosphoric acid, monoalkyl phosphates, and phosphonic acids, but not dialkyl phosphates (107), can be aminoalkylated on the oxygen (108—110). 

R2HP03 0 II H—P—OR phosphonate ester (phosphite) phosphonic acid, mono- and diesters exist... 

R3P03 RO—P—OR 1 OR triphosphite ester (phosphite) hypothetical phosphorous acid, P(0H)2 stmcture is isomeric with phosphonates... 

Pure tetrahedral coordination probably occurs only ia species where there are four identical groups and no steric distortions. Both PCU and PBr" 4, present ia soHd phosphoms haUdes, appear to have poiat symmetry. Other species, eg, H PO and POCl, have only slightly distorted tetrahedra. Similar geometries occur ia salts, esters, and other derivatives of phosphoric, phosphonic, and phosphinic acids as well as phosphine oxides and phosphonium salts. 

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). 

This reaction is catalyzed by hydrogen chloride and yields can be essentially quantitative when using either free phosphonic acid or its diesters. The flame retardant, Eyrol 6, produced by Akzo Chemicals, Inc. and used for rigid urethane foams, is synthesized as follows (24). 

The reaction of phosphoms trichloride and water is highly exothermic and vigorous. Depending on the mole ratio of H2O/PCl, three different products can result from hydrolysis. If the ratio is greater than 3, phosphonic acid is produced ... 

If the ratio is 2.5—3, the product is a mixture of phosphonic and pyrophosphonic acids ... 

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