Phosphonic organophosphorus compounds

Among /1-thiosubstituted organophosphorus compounds bearing chiral groups, phosphono methyl thiazolines (Sect. 2.2.1, Scheme 8) and o-sulfanyl aryl phos-phonamides or phosphinoxides (Sect. 3.3, schemes 20 and 21) have already been mentioned. As a complement to this, some recent synthesis of non racemic /1-sulfinyl phosphines and phosphonates and thiazolidinyl phosphonates are reported below. Moreover, some chiral )8-thio-substituted phosphines have been used as metal ligands in asymmetric catalysis and are listed in Sect. 5.3. 

The Role of Phosphonates in Living Systems, Hilderbrand, R.L., Ed., CRC Press, Boca Raton, FL, 1983 — Contributed chapters survey the role of naturally occurring organophosphorus compounds (containing a C-P bond) in biological systems and the use of a wide variety of organophosphorus compounds for the regulation of metabolism and the treatment of disease. 

The final volume of Organophosphorus Compounds , edited by Kosolapoff and Maier, contains chapters on phosphonic acids and their derivatives1 and organic derivatives of thio- (seleno-, telluro-)phosphoric acids.16... 

Phosphinates are a class of organophosphorus compounds, the metabolism of which has received less attention than that of phosphates (see above) or phosphorothioates and P-halidc compounds (see below). Many phosphinates are rapid but transient inhibitors of acetylcholinesterase and carboxyl-esterases. And like organophosphates and phosphonates, phosphinates are substrates of arylesterases (EC 3.1.1.2). This is exemplified by 4-nitrophen-yl ethyl(phenyl)phosphinate (9.62), whose (-)-enantiomer was hydrolyzed by rabbit serum arylesterase almost 10 times faster than the (+)-enantiomer [133],... 

Phosphate and phosphonate molecules have a very high affinity for calcium carbonate surfaces, as shown by their influence on the precipitation and growth of calcite [164-166]. Accordingly, organophosphorus compounds such as alkylphosphoric acids [167-169] and phosphonic acid-terminated polyoxyethylene [170, 171] have been used to modify the surface of CaCOs powders. 

Synthetic studies for the discovery of effective antidotes for cholinesterase inhibitors are continuing . Various reactivity studies of oximates with different functional organophosphorus compounds, such as phosphinates, phosphonates, phosphates and thiono analogues (shown in Scheme 5), have been reported . ... 

Diisopropyl Methyl Phosphonate DIMP Organophosphonates Organophosphorus Compounds... 

Little is known about the reactions of radical cations of organophosphorus compounds (P such as aryl phosphates and phosphonates as caged compounds and reagents in organic syntheses [85-91]. To elucidate PET reactions including P as the key intermediate, PR and -y-R are used here. 

The reaction of phosphonic acid chloride (254) with (S)-proline ethyl ester afforded a mixture of diasteromeric amides (255) in high diastereoselectivity. The diastereomers (255) can easily be purified by chromatography. The chiral, practically optical pure organophosphorus compound (256) was obtained from purified (255) by acid alcoholysis. 

Our radiolysis studies also indicate that phosphonates react quite slowly with the superoxide anion radical. Although our studies do not support the formation of radical cations as an initial oxidation step, we cannot rule out the possibility that radical cations are not involved in the oxidation of the C—P bond, as previously proposed [44], It is also possible that more electron-rich organphosphorus compounds or organophosphorus compounds in the adsorbed state may exhibit different redox and hydroxyl radical chemistries than what is observed under pulse radiolysis employing homogeneous conditions. 

Recently, another class of neutral organophosphorus compounds, namely, N,N-dialkyl carbamoyl methyl phosphonate (CMP) (59) and its phosphine oxide analog (CMPO) have received attention due to their ability to extract even trivalent actinides from acidic solutions along with the hexa- and tetravalent actinide ions. These biden-tate phosphorus-based neutral extractants are reported to be stronger extractants as compared to TOPO (59-62). Pu(IV) and U(VI) are extracted as per the following extraction equilibria ... 

Comparison of the two pseudo-on-flow NMR chromatograms reveals that compounds 1,2 and 3 are organophosphorus compounds (Table 6.5), but only compounds 2 and 3 are phosphonates and related to chemical weapons. In fact, compound 2 is a degradation product of compound 3... 

F. R. Harley (Ed.), The chemistry of organophosphorus compounds phosphine strategy for the synthesis of functionalized phosphonic acids, Heteroatom Chem. 1997, 8, 103-122. 

The maximum flame temperatures of polymers to which P-containing flame retardants have been added are normally lower than those of unmodified polymers. The low LOI values (18-26%) of the volatile low molecular weight organophosphorus compounds (phosphates, phosphonates, phosphites) indicate their insufficient activity in the gas phase... 

FIGURE 57.5. Subclasses of neuropathy target esterase (NTE) inhibitors. Type A inhibitors include phosphates, phosphonates, and phosphoramidates these are neuropathic and capable of aging. T pe B inhibitors include phosphinates, sulfonates, and carbamates these are nonneuropathic and not capable of aging. However, inhibition of NTE with a type B inhibitor will protect against organophosphorus compound-induced delayed neurotoxicity (OPIDN) from subsequently administered type A inhibitors. Reproduced with permission from Richardson (2005). 

I would like to tell you another case in which we proposed the reaction mechanism before we carried out the reaction in the laboratory. Fortunately the result came out as predicted. We were interested in making some organophosphorus compounds containing two phosphonous acid chloride groups as shown in the following formula ... 

Meisters, A., and Swan, J. M., Organophosphorus compounds. Part 5. Dialkyl alkylphosphonates from alkyl haUdes and sodium dialkyl phosphonates in liquid ammonia, Aust. J. Chem., 18, 163. 1965. 

Yuan, C., Li, C., and Ding. Y. Studies on organophosphorus compounds. Part 51. A new and facile route to 2-substituted l,l-cyclopropauediylZ w(phosphonic acids), Synthesis, 854, 1991. 

Dialkyl phosphites react slowly with epoxy ketones at room temperature in the presence of a catalytic amount of sodium metal to form dialkyl l-hydroxy-2,3-epoxypropylphosphonates in 41-99% yields.Similarly, dialkyl phosphites react with f7.v-]-fonnyl-l-trimethylsilyl-l,2-cpoxy-alkanes in the presence of DBU in THF to give dialkyl ] -hydroxy-2-trirnethylsilyl-2,3-epoxy ilkyl-phosphonate in high yields (84%, Scheme 4.16).By contrast, DBU or EtjN in C,H, at reflux was found inefficient for the addition of dimethyl phosphite to the epoxide derived from chalcone. The reaction is best carried out in the presence of KF2H2O to produce a diastereomeric mixture of hydroxyphosphonates free from other organophosphorus compounds. 

Yuan, C.-Y., Wang, K., and Li, Z.-Y., Studies on organophosphorus compounds. Part 110. Enantioselective reduction of 2-keto-3-haloalkane phosphonates by baker s yeast. Heteroatom Chem., 12, 551,... 

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