Bis Phosphoric Acids Research Articles

Chiral Bisphosphoric Acids and Their Applications in Asymmetric Catalysis.

Asymmetric Brønsted acid catalysis has been recognized as a powerful concept for asymmetric synthesis. In the process of pursuing more robust and highly effective chiral Brønsted acid catalysts, chiral bisphosphoric acids have received much attention in the last two decades. Their unique catalytic properties are mainly attributed to the inherent intramolecular hydrogen bonding interactions that could increase the overall acidity and tune the conformation property. Integrating hydrogen bonding into the catalyst design, quite a few structurally unique and effective bisphosphoric acids have been synthesized, which frequently exhibited superior selectivity in a broad range of asymmetric transformations. This review summarizes the status quo of chiral bisphosphoric acid catalysts and their applications in catalyzing asymmetric transformations.

Multifunctional Organocatalysts - Singly-Linked and Macrocyclic Bisphosphoric Acids for Asymmetric Phase-Transfer and Brønsted-Acid Catalysis.

The linking of phosphoric acids via covalent or mechanical bonds has proven to be a successful strategy for the design of novel organocatalysts. Here, we present the first systematic investigation of singly-linked and macrocyclic bisphosphoric acids, including their synthesis and their application in phase-transfer and Brønsted acid catalysis. We found that the novel bisphosphoric acids show dramatically increased enantioselectivities in comparison to their monophosphoric acid analogues. However, the nature, length and number of linkers has a profound influence on the enantioselectivities. In the asymmetric dearomative fluorination via phase-transfer catalysis, bisphosphoric acids with a single, rigid bisalkyne-linker give the best results with moderate to good enantiomeric excesses. In contrast, bisphosphoric acids with flexible linkers give excellent enantioselectivities in the transfer-hydrogenation of quinolines via cooperative Brønsted acid catalysis. In the latter case, sufficiently long linkers are needed for high stereoselectivities, as found experimentally and supported by DFT calculations.

A supramolecular double-helix based on complementary phosphate-guanidinium pairing.

A double-helical supramolecular structure was formed by self-assembly of 1,1'-binaphthyl-based bisguanidines and bisphosphoric acids. Interestingly the homochiral (S,S) + (S,S)-pair forms a left-handed double-helix, while the heterochiral (S,S) + (R,R)-pair forms a non-helical dimer.

Rigidly Tethered Bis-phosphoric Acids: Generation of Tunable Chiral Fluorescent Frameworks and Unexpected Selectivity for the Detection of Ferric Ions.

We describe the straightforward synthesis of a series of bis-phosphoric acids (R,R)-1 a-d, featuring two chiral 1,1'-binaphthyl-phosphoric acid units that are tethered by rigid, π-conjugated linkers. The nature of the linker has a profound influence on the properties of the bis-phosphoric acids, such as their self-association behavior and their interaction with metal ions. This led to the identification of one preferred bis-phosphoric acid (R,R)-1 d, which shows selective fluorescence quenching in the presence of ferric ions (Fe3+ ). Thus, (R,R)-1 d could be applied for the detection of Fe3+ , even in the presence of a variety of other metal ions. The chiral nature of the bis-phosphoric acid enables the interaction with Fe3+ to be followed by CD spectroscopy, providing a complementary detection mode with the same probe.

Hydrogen Bonds-Enabled Design of a C1-Symmetric Chiral Brønsted Acid Catalyst

We have developed new C1-symmetric, chiral bis-phosphoric acids with an electron-withdrawing group as one of the two substituents. This C1-symmetric, chiral bis-phosphoric acid with a pentafluorophenyl group performs exceptionally well in the asymmetric Diels–Alder reaction of acrolein, methacrolein, and α-haloacroleins with substituted amidodienes. Control over the atropisomeric catalyst structure, enhancement of the catalytic activity, and differentiation of the asymmetric reaction space is possible by the remote control of the pentafluorophenyl group. Furthermore, we have conducted theoretical studies to clarify the roles of both intra- and intermolecular hydrogen bonds in the C1-symmetric chiral environment of chiral bis-phosphoric acid catalysts. The developed strategy, C1-symmetric catalyst design through hydrogen bonding, is potentially applicable to the development of other chiral Bronsted acid catalysts.

ChemInform Abstract: Design and Synthesis of Chiral Binaphthol‐Derived Bisphosphoric Acids and Their Application in the Catalytic Enantioselective Hydrogenation of Quinolines.

AbstractAmong various bisphosphoric acids synthesized, the derivative BNPE is elaborated as the optimal one.

Design and Synthesis of Chiral Binaphthol‐Derived Bisphosphoric Acids and Their Application in the Catalytic Enantioselective Hydrogenation of Quinolines

AbstractA series of binaphthol‐based bisphosphoric acids were successfully developed with inclusion of rigid cyclic phosphamide and phosphonate motifs. These chiral bisphosphoric acids were used as chiral organocatalysts in the hydrogen transformation of a series of quinolines to investigate their enantioselective catalytic activity.

Solvent Extraction of Li+ using Organophosphorus Ligands in the Presence of Ammonia

In this work, the selective extraction of Li+ with the aid of organophosphorus ligands (H-OP) including phenylphosphonic (H-PHO), phenylphosphinic (H-PHI) and bis(2-ethylhexyl) phosphoric (H-BIS) acids in the absence and presence of ammonia was studied. Adding NH3 to the aqueous phase resulted in significant improvement in the % extraction of Li+ into the organic phase containing H-OP ligands. The highest % extraction values obtained in the case of H-PHO, H-PHI, and H-BIS were 43.2%, 45.7%, and 90.0%, respectively. Two mechanisms were inferred; the first was that the extraction equilibrium reaction of LiCl + H-OP ↔ Li-OP + HCl shifted forward due the reaction of the produced HCl with NH3. The second mechanism was that the Li+/NH4+ exchange of NH4-OP (produced from the reaction of H-OP with NH3) was easier than Li+/H+ exchange of H-OP itself. Competitive extraction experiments indicated that the selectivity factors of Li+ over Na+ and K+ were strongly dependent on the concentration of H-OP ligands which suggested that aggregation of ligand molecules via hydrogen bonding is the limiting factor for selectivity.

Recovery of uranium (VI) from concentrated phosphoric acid by mixtures of new bis(1,3- dialkyloxypropan-2-yl) phosphoric acids and tri-n-octylphosphine oxide

Three new extractants, namely bis(1,3-dihexyloxypropan-2-yl) phosphoric acid, bis(1,3-dioctyloxypropan-2-yl) phosphoric acid and bis(1,3-di-2-ethylhexyloxypropan-2-yl) phosphoric acid, were synthesized and tested in mixture with tri-n-octyl phosphine oxide (TOPO) in Isane IP 185 for the recovery of uranium (VI) from 5.3molL−1 synthetic phosphoric acid and 30% wt P2O5 industrial wet phosphoric acid. The results were compared with those previously obtained with bis(1,3-dibutoxypropan-2-yl) phosphoric acid (BiDiBOPP), under similar experimental conditions. The increase of the length of the alkyloxy chains of bis(1,3-dialkyloxypropan-2-yl) phosphoric acid is responsible for an increase of the distribution coefficients of both uranium (VI) and iron (III) whereas steric hindrance effect arising from the increase of branching improves the selectivity for uranium (VI) against iron (III). A quantitative relationship between the distribution coefficients of uranium (VI) measured for the series of 7 extractants and two molecular descriptors has been developed. This opens a way for computer-guided design of new phosphoryl-containing extractants.

ChemInform Abstract: Binaphthol‐Derived Bisphosphoric Acids Serve as Efficient Organocatalysts for Highly Enantioselective 1,3‐Dipolar Cycloaddition of Azomethine Ylides to Electron‐Deficient Olefins.

AbstractAmong several chiral bisphosphoric acids evaluated, oxygen‐linked acid BNO provides the highest level of stereoselectivity.

Binaphthol-Derived Bisphosphoric Acids Serve as Efficient Organocatalysts for Highly Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Ylides to Electron-Deficient Olefins

A variety of chiral bisphosphoric acids derived from binaphthols have been evaluated for enantioselective 1,3-dipolar cycloaddition reactions, revealing that the feature of the linker in the catalysts exerted great impact on the stereoselectivity. Among them, the oxygen-linked bisphosphoric acid 1a provided the highest level of stereoselectivity for the 1,3-dipolar cycloaddition reaction tolerating a wide range of substrates including azomethine ylides, generated in situ from a broad scope of aldehydes and α-amino esters, and various electron-deficient dipolarophiles such as maleates, fumarates, vinyl ketones, and esters. This reaction actually represents one of the most enantioselective catalytic approaches to access structurally diverse pyrrolidines with excellent optical purity. Theoretical calculations with DFT method on the formation of azomethine ylides and on the transition states of the 1,3-dipolar cycloaddition step showed that the dipole and dipolarophile were simultaneously activated by the bifunctional chiral bisphosphoric acids through the formation of hydrogen bonds. The effect of the bisphosphoric acids on reactivity and stereochemistry of the three-component 1,3-dipolar cycloaddition reaction was also theoretically rationalized. The bisphosphoric acid catalyst 1a may take on a half-moon shape with the two phosphoric acid groups forming two intramolecular hydrogen bonds. In the case of maleates, one phosphate acts as a base to activate the 1,3-dipole, and simultaneously, the two hydroxyl groups in the catalyst 1a may respectively form two hydrogen bonds with the two ester groups of maleate to make it more electronically deficient as a much stronger dipolarophile to participate in a concerted 1,3-dipolar cycloaddition with azomethine ylide. However, in the cases involving acrylate and fumarate dipolarophiles, only one hydroxyl group forms a hydrogen bond with the ester functional group to lower the LUMO of the C-C double bond and another one is remained to adjust the acidity and basicity of two phosphoric acids to activate the dipole and dipolarophile more effectively.

Preparation and Performance Properties of a Series of Novel Anionic Gemini Surfactants

Abstract Anionic Gemini surfactants having two phosphate head groups and two decyl head groups were prepared in good yield. These surfactants were prepared by two step process. (i) Preparation of decyl phosphate from pyrophosphoric acid and decanol. (ii) Preparation of bis-phosphoric acid from decyl phosphate, (CH3)4NOH and different spacers by using acetonitrile as solvent. The synthesized surfactants structures were verified by FT IR, and 1H NMR spectroscopy. The physical and performance properties like surface tension and interfacial tension, foaming, wetting and emulsion stability of disodium salts of bis-phosphoric acids were also evaluated. The effects of the spacers on the properties were analyzed. It was found that properties were significantly influenced by slight variation of spacers.

Aqua-Impregnated Resins. 2. Separation of Polyvalent Metal Ions on Iminodiacetic and Polyacrylic Resins Using Bis(2-ethylhexyl) Phosphoric and Bis(2-ethylhexyl) Dithiophosphoric Acids as Organic Eluents

This paper dedicated to the further development of the novel aqua-impregnated-resin (AIR) technique reports the results obtained by studying the column separation of equimolar mixtures of Cu(2+), Al(3+), and Zn(2+) on iminodiacetic (IDA) and polyacrylic (PAR) resins by using 0.2 M heptane solutions of either bis(2-ethylhexyl) phosphoric acid (DEHPA) or bis(2-ethyhexyl) dithiophosphoric acid (DEHDTPA) as selective eluents for extractive desorption of metal ions from the resin phase. The quantitative separation of Cu(2+)-Al(3+) mixtures has been achieved by sequential elution of metals from PAR with DEHDTPA and H(2)SO(4) solutions. Purification of Cu(2+) from Al(3+) and/or Zn(2+) and Al(3+) from Cu(2+) and Zn(2+) is achieved by extractive elution of metal mixtures from IDAR or PAR with DEHPA or DEHDTPA solutions, respectively, followed by stripping of the purified metals with 1.1 M H(2)SO(4). The resulting purity of metals obtained with the yield of >96% exceed 95%.

Extraction of scandium, cerium, promethium, and europium with dibutylphosphoric, bis(2-ethylhexyl)phosphoric, and dioctylphosphoric acids in Freon 113

The extraction of Sc, Ce, Pm, and Eu from aqueous solutions of HClO4 and HNO3 into organic phases constituted by solutions of dialkylphosphoric acids in Freon 113 was studied. The effects of the kind of inorganic acid, concentration of hydrogen ions in the aqueous phase and concentration of the extracting agent in the organic phase were examined. Based on the dependences of the distribution ratios of the metals on the above variables, the compositions of the extractable complexes were determined and the extraction constants calculated. The dimerization constants and distribution constants of the monomer were also determined for dibutylphosphoric and bis(2-ethylhexyl)phosphoric acids.

Synthesis and stereochemical study of some biologically relevant phosphoglycerides: Dicarboxylic phosphatidylcholines and bis (diacylglycero) phosphoric acids

Abstract Dicarboxylic (glutaryl or succinyl) phosphatidylcholines, and stereoisomeric bis (diacylglycero) phosphoric acids were synthesized. Their structures and stereoconfiguration were determinated by chemical, spectrometric and biochemical methods.

Vibrational Spectra and Normal Coordinate Treatment of Bis(2-ethylhexyl)phosphoric Acid

The infrared and Raman spectra of the bis(2-ethylhexyl)phosphoric acids [(C8H17O)2PO(OH), (C8H17O)2PO(OD)] and its sodium salt (C8H17O)2PO(ONa) were obtained from 4000–100 cm−1. On the basis of an approximate normal coordinate treatment and using a cyclic dimeric model, theoretical band assignments were made. These results were compared with those obtained for dimethylphosphinic acid.

Synthesis of some triamides of phosphorus acids

1. Ethylenemides of dialkylamido- and bis(dialkylamido)phosphorous, phosphoric, and thiophosphoric acids were produced. 2. The triethyleneimide of phosphorous acid was produced, and the triethyleneimide of thiophosphoric acid was produced by adding sulfur to it.