Phosphorus compounds derivatives

Hexacoordinated phosphorus compounds derived from phthalocyanines have been similarly prepared. Hanack investigated the reaction of metal-free phthalocyanines with POBr3 or POCI3 in presence of pyridine [98]. The corresponding dihydroxyphosphorus phthalocyanine hydroxides 60 were characterized. 

A review on the chemistry of thio derivatives of trivalent phosphorus acids which covers the literature to 1986, includes a section on pentaco-ordinate phosphorus compounds derived from addition to a-diketones and unsaturated systems activated to nucleophilic attack by electron withdrawing groups. Chemical bonding in hypervalent molecules has been discussed and qualitative bonding concepts developed to supersede the dsp and d sp models. A review on the mechanism and stereochemistry of the Wittig olefination reaction inevitably includes a discussion of the equilibrium between betaine and 1,2-oxaphosphetane intermediates. A correction has been published to reference 19 of Chapter 2 in SPR14, Vol.21, concerning the Mitsunobu Reaction. ... 

Phosphorus Compounds Derived from Aldehydes AND Ketones. 

Besides phosphines and phosphites preferentially used as ligands in hydro-formylation, phosphoramidites have also been proposed. Phosphoramidites (sometimes also called phosphoroamidites) are a class of organic phosphorus compounds derived from phosphites in which the P-OR groups have been replaced by P-NR2 groups (Figure 2.31). Three different P-substituents produce a chiral (stereogenic) phosphorus atom. Phosphoramidites play a crucial role in the synthesis of nucleic acids [1] and have also been frequently considered as mono- or bidentate ligands in transition-metal catalysis [2]. 

Organo-phosphorus Compounds, Derivates of Phosphorus-based Acids... 

Low-valent nitrogen and phosphorus compounds are used to remove hetero atoms from organic compounds. Important examples are the Wolff-Kishner type reduction of ketones to hydrocarbons (R.L. Augustine, 1968 D. Todd, 1948 R.O. Hutchins, 1973B) and Barton s olefin synthesis (p. 35) both using hydrazine derivatives. 

Phosphorus Compounds. Acyclic phosphorus compounds containing only one phosphorus atom, as well as compounds in which only a single phosphorus atom is in each of several functional groups, are named as derivatives of the parent structures listed in Table 1.12. Often these... 

Organophosphorus Derivatives. Neopentyl glycol treated with pyridine and phosphorus trichloride in anhydrous dioxane yields the cycHc hydrogen phosphite, 5,5-dimethyl-l,3-dioxaphosphorinane 2-oxide (2) (32,33). Compounds of this type maybe useful as flameproofing plasticizers, stabilizers, synthetic lubricants, oil additives, pesticides, or intermediates for the preparation of other organophosphoms compounds (see Flame retardants Phosphorus compounds). 

Phosphorus compounds exhibit an enormous variety of chemical and physical properties as a result of the wide range ia the oxidation states and coordination numbers for the phosphoms atom. The most commonly encountered phosphoms compounds are the oxide, haUde, sulfide, hydride, nitrogen, metal, and organic derivatives, all of which are of iadustrial importance. The hahde, hydride, and metal derivatives, and to a lesser extent the oxides and sulfides, are reactive iatermediates for forming phosphoms bonds with other elements. Phosphoms-containing compounds represented about 6—7% of the compound hstiugs ia Chemical Abstracts as of 1993 (1). 

Phosphatidic acids not only are intennediates in the biosynthesis of triacylglycerols but also are biosynthetic precursors of other members of a group of compounds called phosphoglycerides or glycerol phosphatides. Phosphorus-containing derivatives of lipids are known as phospholipids, and phosphoglycerides are one type of phospholipid. 

One of the most widely used methods for the formation of phosphate esters involves the conversion of a P-N bond of a phosphorus(III) compound to a P-O bond by ROH, catalyzed by l//-tetrazole, followed by oxidation to the phosphorus(V) derivative ... 

The aromatic heterocycle phosphabenzene C5H5P (analogous to pyridine) was reported in 1971, some years after its triphenyl derivative 2,4,6-Ph3C5H2P. See also HP=CH2 29) nd [P(CN)2] ° (p. 484). The burgeoning field of heterocyclic phosphorus compounds featuring... 

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. 

Akiba investigated the electrochemical behavior of a variety of phosphorus octaethylporphyrin derivatives all compounds showing a single reversible oxidation wave [91]. The absolute difference in potential between the first ring-centered oxidation and reduction varies from 2.19 to 2.36 V in dichloromethane. These values are within the range of the HOMO-LUMO gap observed for most metalloporphyrins. 

The formation and reaction of peroxyl radicals derived by reaction of tervalent phosphorus compounds with oxygen have attracted interest. Photolysis of trialkyl phosphites in oxygenated solutions of aromatic hydrocarbons gives phenols. " Phosphorus trichloride reacts with 1,2-dichloroethylene, in the presence of oxygen, to give (17). It is tempting to suggest that both reactions occur via similar intermediates, e.g. (15) and (16). 

This report covers the s oo ficent work on ell orpsoo-phosphorus compounds end their derivatives, together with the physical methods involved, over the period from July 1969 to Jur>e 1970 2 2pp 7 00 (Vof t still masbh C4 00)... 

The central importance of phosphorus and its derivatives in our world leads to the question as to where the element came from phosphorus compounds must have been present on the Earth after its formation, but we do not know their source. Were they already present in planetesimals, or was phosphorus brought to Earth from space (in an elemental form or as compounds) ... 

The RNA world hypothesis then rekindled interest in the still open question of the origin of the phosphorus. How could acceptable synthetic routes to the nucleic acids be developed, if it was not even clear which phosphate derivatives were available on the primeval Earth An RNA world is not possible without reactive phosphates or similarly efficient phosphorus compounds Thus, the search for effective phosphorus or phosphate sources continued unabated. 

Analysis of the Murchison meteorite led to a completely different type of phosphorus compound the only phosphorus-containing compounds found were alkanephos-phonic acids. Spurred on by these results, de Graaf et al. (1995) irradiated mixtures of o-phosphorous acid in the presence of formaldehyde, primary alcohols or acetone with UV light (low pressure Hg lamp, 254 nm with a 185-nm component) and obtained phosphonic acids, including hydroxymethyl and hydroxyethyl phosphonic acids, which had been found in the Murchison meteorite. Alkanephosphonic acids can be derived from phosphorous acid, with a P-H bond being replaced by a P-C bond. 

The reaction of cycloheptaamylose with diaryl carbonates and with diaryl methylphosphonates provides a system in which a carboxylic acid derivative can be directly compared with a structurally analogous organo-phosphorus compound (Brass and Bender, 1972). The alkaline hydrolysis of these materials proceeds in twro steps, each of which is associated with the appearance of one mole of phenol (Scheme Y). The relative rates of the two steps, however, are reversed. Whereas the alkaline hydrolysis of carbonate diesters proceeds with the release of two moles of phenol in a first-order process (kh > fca), the hydrolysis of methylphosphonate diesters proceeds with the release of only one mole of phenol to produce a relatively stable aryl methylphosphonate intermediate (fca > kb), In contrast, kinetically identical pathways are observed for the reaction of cycloheptaamylose with these different substrates—in both cases, two moles of phenol are released in a first-order process.3 Maximal catalytic rate constants for the appearance of phenol are presented in Table XI. Unlike the reaction of cycloheptaamylose with m- and with p-nitrophenyl methylphosphonate discussed earlier, the reaction of cycloheptaamylose with diaryl methylphosphonates... 

As recently as 1965, Thoma and Stewart predicted that alterations in reaction rates [in the presence of the cycloamyloses] should be anticipated whose magnitude and sign will fluctuate with the reaction type, and added that at the present juncture, it is impossible to sort out confidently. . . which factors may contribute importantly to raising or lowering the activation energy of the reaction. In the short interval between 1965 and the present, a wide variety of cycloamylose-induced rate accelerations and decelerations have, indeed, been revealed. More importantly, rate alterations imposed by the cycloamyloses can now be explained with substantially more confidence. The reactions of derivatives of carboxylic acids and organo-phosphorus compounds with the cycloamyloses, for example, proceed to form covalent intermediates. Other types of reactions appear to be influenced by the dielectric properties of the microscopic cycloamylose cavity. Still other reactions may be affected by the geometrical requirements of the inclusion process. 

CHEC-II(1996) comprehensively outlines the most commonly used synthetic approaches applied to these types of bicyclic compounds of phosphorus, arsenic, antimony, and bismuth <1996CHEC-II(8)863>. The six classes of compounds listed in this section have received considerable attention over the review period and as such the principal synthetic methods for these compounds are discussed. Schoth et al. <2000CCR101> have reviewed the use of fluorinated 1,3-diketones, 2-trifluoroacetylphenols, and their derivatives in the synthesis of phosphorus compounds. Included in this review is the use of these reagents for the synthesis of various [3.3.1] nonfused and [3.3.0] fused phosphorus bridgehead bicyclic systems. 

Phosphorus compounds occur widely in nature, with some of the most common forms being phosphate rocks and minerals, bones, and teeth. Phosphate minerals include calcium phosphate, Ca3(P04)2 apatite, Ca5(P04)30H fluoroapatite, Ca5(P04)3F and chloroapatite, Ca5(P04)3Cl. Elemental phosphorus was first obtained by H. Brand, and its name is derived from two Greek words meaning "light" and "I bear" because of the phosphorescence of white phosphorus due to slow oxidation. 

The lithium salt of the stabilized anion derived from dithiane also provides displacement of halogen at phosphorus for the generation of species readily converted into additional functionalized organo-phosphorus compounds.69 The resultant materials are suitable for a wide range of applications, both as final products and as reagents for additional transformations. 

Phosphorus compounds, 19 19-73 bond properties of, 19 26 chemical properties of, 19 20-31 chiral-centered, 19 25-26 economic aspects of, 19 67-69 as flame retardants, 19 51 inorganic, 11 487-488 oxidation states, coordination numbers, and geometries of, 19 20-26 as oxyacid derivatives, 19 20 reactive organic, 11 496 497 titanium in, 25 56-57 triply connected, 19 25 U.S. prices of, 19 68t U.S. production of, 19 67t... 

Vanadium is beneficial and possibly essential for humans. It is certainly essential for a number of organisms. Vanadate (oxidation state V) and its derivatives are phosphate analogues, showing both ground state and transition state analogy (both structural and electronic) with phosphorus compounds. The analogy of five-coordinate vanadium compounds with the transition state of phosphate ester hydrolysis is well documented, and explains why so many vanadium compounds are potent inhibitors of phosphatases, ribonucleases and ATPases. 

Intermediates such as 224 resulting from the nudeophilic addition of C,H-acidic compounds to allenyl ketones such as 222 do not only yield simple addition products such as 225 by proton transfer (Scheme 7.34) [259]. If the C,H-acidic compound contains at least one carbonyl group, a ring dosure is also possible to give pyran derivatives such as 226. The reaction of a similar allenyl ketone with dimethyl mal-onate, methyl acetoacetate or methyl cyanoacetate leads to a-pyrones by an analogous route however, the yields are low (20-32%) [260], The formation of oxaphos-pholenes 229 from ketones 227 and trivalent phosphorus compounds 228 can similarly be explained by nucleophilic attack at the central carbon atom of the allene followed by a second attack of the oxygen atom of the ketone at the phosphorus atom [261, 262], Treatment of the allenic ester 230 with copper(I) chloride and tributyltin hydride in N-methylpyrrolidone (NMP) affords the cephalosporin derivative 232 [263], The authors postulated a Michael addition of copper(I) hydride to the electron-... 

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