Phosphonates phosphorus source

Bacteria are also able to use a large number of organophosphorus insecticides, alkyl phosphates, phosphonates, and the herbicide Glyphosate as phosphorus sources. 

Previous syntheses of terminal alkynes from aldehydes employed Wittig methodology with phosphonium ylides and phosphonates. 6 7 The DuPont procedure circumvents the use of phosphorus compounds by using lithiated dichloromethane as the source of the terminal carbon. The intermediate lithioalkyne 4 can be quenched with water to provide the terminal alkyne or with various electrophiles, as in the present case, to yield propargylic alcohols, alkynylsilanes, or internal alkynes. Enantioenriched terminal alkynylcarbinols can also be prepared from allylic alcohols by Sharpless epoxidation and subsequent basic elimination of the derived chloro- or bromomethyl epoxide (eq 5). A related method entails Sharpless asymmetric dihydroxylation of an allylic chloride and base treatment of the acetonide derivative.8 In these approaches the product and starting material contain the same number of carbons. 

In all the experiments, the main decomposition products were phosphonates, which are also stable in concentrated solutions of Mg and Ca chlorides. In some experiments, pyrophosphate, and in smaller amounts triphosphate, could also be detected. The authors thus assume that the primeval ocean contained phosphonates as a source of phosphorus for reactions leading to biochemically relevant molecules. Iron meteorites could have delivered sufficient reduced phosphorus (Fe3P) to the primeval Earth, so the question of prebiotic phosphorus chemistry should be looked at in more detail in the future (Pasek and Lauretta, 2005). 

In the second instance, two approaches seem to be worthy of special note. The synthetic utility of elemental phosphorus based on it acting as a radical trap appears to be quite valuable, but additional effort is required to determine the variability of the source of the organic free radicals. (Is there some other, more efficacious, source of organic free radicals that works better with this system than acylated iV-hydroxy-2-pyridones ) The other approach that appears ripe for development is the hydrolysis/elimination with "phosphorates" derived from the oxidative addition of white phosphorus to alkenes. We look forward to the continued development of such facile approaches toward the preparation of fundamental phosphonic acids. 

Another important source of chiral auxiliaries for the synthesis of optically active phosphorus derivates are the C2 symmetric diamines such as 1,2-diaminocyclohex-anes. In 1994, Hanessian and co-workers described the use of A,/V -dimethyl-(R,R)-1,2-diaminocyclohexane 93 as a chiral auxiliary in the synthesis of optically pure or enantiomerically enriched a-alkyl a-amino phosphonic acids [49], Starting from easily accessible optically pure diamine 93, they synthesized in good yield (75 %) enantiomerically pure (R,R)-ethylphosphonamide 94 by condensation with ethyl phosphonic dichloride in benzene in the presence of triethylamine (Scheme 43). 

Like other dissolved organic nutrients, the chemical composition of organic P is relatively unknown. Marine dissolved organic phosphorus (DOP) composition has been mostly identified as particular compound classes such as monophosphate esters, phosphonucleotides, nucleic acids, phospholipids, phosphonates and polyphosphates (Benitez-Nelson, 2000). Kolowith et al. (2001) found that monophosphate esters and phosphonates are major components in the Pacific Ocean, the Atlantic Ocean and the North Sea. ATP (adenosine triphosphate), ubiquitous in aU living cells, has been used as a model DOP compound in radiotracer experiments to obtain information on P sources and fluxes in natural environments (Bjorkman et al., 2000 Karl and Bossard, 1985) and cyanobacterial cultures (Fu et al., 2006). 

Apart from the results from a very few isolated studies, little is yet known about the breakdown of phosphorus-carbon-bonded compounds in vertebrates or invertebrates . However, a very wide range of bacteria are capable of destroying the phosphorus-carbon bond, often in individual compounds, sometimes in a range of chemically similar structures . The outstanding feature is the way in which many bacteria can utilize phosphonic acids as the sole source of phosphorus, and so catabolize simple phosphonic acids (but not... 

The presence of electron-withdrawing groups positioned on an aromatic nucleus bonded directly to phosphorus can be a source of instability in the phosphorus-carbon bond. This situation is found particularly in (4-nitrophenyl)phosphonic acids. (2-Methoxy-4-nitrophenyl)phosphonic acid can be demethylated in 40% HBr, but cleavage of the carbon-phosphorus bond becomes more pronounced in a reaction with 48% HBr moreover, hydrogenation of the same acid over Raney nickel yields the expected (4-amino-2-methoxyphenyl)phosphonic acid, but a similar reduction of (2-hydroxy-4-nitrophenyl)-phosphonic ac id results in the separation of 3-aminophenol. These and other, similar, reactions have been surveyed by Freedman and Doak ". ... 

McMillan and Quinn, 1994), possibly indicating that phosphonates may be used by bacteria other than as sources of phosphorus. 

Another possible source of a phosphorus pendant group was [(2-dihydro grarsinoylphenylamino)methyl]phosphonic acid, which was used to modify the Amberlite XAD-16 polymeric matrix. Subramanian et al. also modified the polystyrene-divinylbenzene copolymer beads (Amberlite XAD-16) by anchoring 6,6,6-trifluoro-2,5-dioxo-4-(thiophene-2-carbonyl)he yl-phosphinic acid in its matrix in order to obtain a new chelating ion-exchange multidentate grafted polymer (Scheme 11.9). ... 

---