Phosphorous derivatives

Thanks to this general procedure, some classes of tetrathiahehcene-based alkyl and aryl phosphorous derivatives are now available, including phosphine—borane complexes (2015JO3921), phosphanes (2011EJO5649, 2013IC7995), phosphine oxides (2014EJO2694), and a diphosphonate (2011EJO5649). 

These systems represent a novel class of potential chiral Hgands for organo- and organometallic homogeneous catalysis. It shorrld be underlined 

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Flame retardants designated for nylon include halogenated organic compounds, phosphorous derivatives, and melamine cyanurate (160—163). Generally, flame retardants are difficult to spin in nylon because of the high loading required for effectiveness and their adverse effects on melt viscosity and fiber physical properties. 

Phosphorous derivatives of fatty acids were also prepared by heating acyl chlorides, bromoethyl esters, or vinylbromo esters with triethyl phosphite in an Arbusov reaction [88-90] see Eqs. (42)-(44) ... 

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 phosphorus containing CDA (87) has also been described for the estimation of the enantiomeric excess of chiral amines80. The phosphorus CDA 87 is formed quantitatively and instantaneously in situ in an NMR tube by reaction of phosphorus trichloride (PCI3) with the chiral diamine 88. Addition to the NMR tube of the chiral amine (IC-NIIo) for which the ee is to be determined gives the diastereomeric phosphorous derivatives ... 

By single electron transfer from an electron donor, e.g. a transition metal ion, a trivalent phosphorous derivative or a base, followed by dissociation of the intermediate diazenyl radical in an aryl radical and dinitrogen. The aryl radical reacts with the solvent or with added reagents in various ways, as shown by the relatively large number of classical named reactions (Sandmeyer, Pschorr, Gomberg-Bachmann, Meerwein reactions). 

The photosolvolysis of 3-nitrophenyl esters is the first example of the use of a light-sensitive protecting-group that has appeared in the literature. 3-Nitrophenyl and the more-sensitive 3,5-dinitrophenyl phosphoric esters undergo photohydrolysis (mercury lamp) to a phosphoric derivative and the corresponding nitrophenol an example of a synthetic application is presented in Scheme 30. 

Table 3 Categorization System in Phosphorous-Derived and Nonfertilizer Phosphate Chemicals Production...

Lewis bases like aliphatic or aromatic amines, sulphoxides, phosphorous derivatives form adducts with / -diketonates, by recrystallization of the hydrated lanthanide fi-diketonates in a solution of the substrate [51,52]. The adducts have also been prepared by extraction of lanthanide salt with a stoichiometric mixture of the /5-diketone and a Lewis base. Alternatively it can be prepared by increasing the pH of an ethanolic-water solution of lanthanide salt, /5 -diketone and the organic substrate. 

The introduction ofan hydrosoluble phosphorous group increasesthe hydrosolubility and the activity of these molecules by supporting their transport in vivo in comparison with their parental aminothiols. Moreover, these kinds of phosphorous derivatives are often more active because they have an intrinsic radioprotective activity and their metabolites have radioprotective activity too. Phosphorothioates offer a slow and prolonged release of radioprotective substances. 

WR-2721 (H2NCH2CH2CH2HNCH2CH2SPO3H2) is one of the best currently known radioprotectors. It was the subject of many studies because of its very high radioprotective effect [11-12]. In spite of some side effects (vomiting in 25% ofthe cases, hypotension, etc), WR-2721 is currently used for a clinical use, because it preferentially protects normal cells. The structure of these phosphorated derivatives is presented in Figure 5 ... 

Most of these phosphorated derivatives present still an interesting radioprotective activity even when mice have been exposed to LD,Qoi /3oj + 2 Gy. Compounds derived from naphthylethylimidazoline are less toxic and sometimes more active. Compounds (30, 31) are less toxic than compounds 28 and 29. However, in derivative 23, the most active of the series, the substitution of an hydrogen atom by a methyl group, giving compound 29, induces a great decrease in the activity, and even a total decrease of radioprotective activity at 10 Gy. In contrast, in the case of phosphorothioate 30, the presence ofa methyl group greatly improves radioprotective properties in comparison with compound 24 which is the less active derivative. The Dose Reduction Factor has been determined as previously described for compounds 27, 28 and 31. Their values are 1.6, 1.8 and 1.6, respectively (Tab. 4). 

The photochemical reaction of phosphorous derivatives with p -benzoquinones has been studied. The Argon matrix isolation of cyclopentadienone has been achieved using a variety of photo -precursors such as o - and p -bezoquinones. />-Benzoquinone and 1,4-naphthoquinone add to cycloheptatriene to afford spirocyclic... 

Phosphor-Derivate reduzieren Nitro-Verbindungen zu Azoxy-Verbindungen, Aminen, Nitrilen und, falls ein entsprechender Reaktionspartner zur Verfiigungsteht, unter intramolekularem RingschluS zu N-Heterocyclen. 

Tervalent phosphorus compounds (phosphorous derivatives) are weil-established reagents for the deoxygenation of amine oxides and nitrones, and they provide a clean and convenient method for the preparation of furazans from furoxans. Mukaiyama et al.425 and Grundmann426 used trialkylphosphites, and they have been widely employed since that time, both with and without solvents.80,85,93,95,97,352 The simple dialkyl- and diarylfuroxans usually require more vigorous conditions (e.g., refluxing triethyl phosphite) than do strained derivatives or the benzofuroxans.85,97... 

Als Aktivierungsreagentien konnen folgende Phosphor-Derivate eingesetzt wer-den ... 

The displacement reactions of the anhydride from O-ethyl phenylphosphonothioate and O-ethyl 0-phenyl phosphorothioic acid have been the subject of separate investigations. The (R,R)-(+)-anhydride 100 was subjected to reactions with a variety of nucleophiles. The latter, which included HO ,NH3 and HS , all appeared to attack the phospho-nothioic phosphorus centre, and the reactions proceeded with inversion of configuration, with the exception of that with HS , from which a racemic product was obtained since it consisted of the ion Ph(EtO)PS2". The principle difference between this substrate example and those considered earlier is that both phosphorus centres are chiral, and hence the thio-phosphoric derivatives, formed concomitantly, are also optically active. 

Non-planar sulfur or phosphorous-derived acidic functions The most extensive use of phosphonates was made in the design of amino acid neurotransmitter antagonists such as glutamate and GABAb antagonists. ... 

Phosphorous derivatives have been shown by Regitz and his collaborators to be useful in the synthesis of substituted hydroxy-1,2,3-triazoles, which probably can be hydrolyzed by analogy to many related synthetic routes... 

Later, the Eli Lilly group [39] reported an improved method, characterized by intercepting the sulfenate (100) with trivalent phosphorous derivatives to give (47a) directly. This process obviated the need for disulfide formation and gave in... 

These mixed anhydrides were adopted for the actual synthesis of peptides in other laboratories, but, as we intend to show it later, the idea to activate the caboxyl group in the form of phosphorous derivatives reemerged time and again and more recently yielded practical results. 

In 2007, Cossy and coworkers [61] demonstrated that small-molecule additives could be used to help inhibit olefin migration in challenging CM reactions (Scheme 12.35). Investigating the CM of lactone 117 with olefin 118 by H-NMR, the desired product 119 was formed in 50% yield, while a 13% yield of the isomerized lactone (120) was formed. A variety of small-molecule additives (5mol%) were then studied to suppress the undesired olefin isomerization. While a number of phosphorous-derived additives were surveyed, two additives clearly stood out as being the most efficient 2,6-dichloro-l,4-benzoquinone and -chlorocatechol. In particular, the 2,6-dichloro-l,4-benzoquinone was able to... 

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