Substituted Phosphorus Compounds Research Articles

Synthetic and computational study of geminally bis(supermesityl) substituted phosphorus compounds

Reaction chemistry of an extremely sterically encumbered phosphinic chloride (Mes*)(2)P(=O)Cl (Mes* = 2,4,6-tri-t-butylphenyl, supermesityl) was investigated. This compound, as well as other compounds bearing two supermesityl groups placed geminally at the central phosphorus atom, shows extremely low reactivity at the phosphorus centre. Nevertheless, some synthetically significant transformations were possible. Reduction with hydridic reagents under forcing conditions yielded the phosphine oxide (Mes*)(2)P(=O)H and a secondary phosphine Mes*(2,4-tBu(2)C(6)H(3))PH. Deprotonation of (Mes*)(2)P(=O)H gave the corresponding phosphinite, which afforded very crowded tertiary phosphine oxides (Mes*)(2)P(=O)R (R = Me and Et) on reactions with electrophiles. While the reaction of the phosphine Mes*(2,4-tBu(2)C(6)H(3))PH with sulfur was surprisingly facile (although under forcing conditions), we have been unable to chlorinate or deprotonate this phosphine. All new compounds were fully characterised with multinuclear NMR, IR, Raman, MS, microanalyses and single crystal X-ray diffraction. Our computations (B3LYP and M06-2X level) show that strain energies of (synthetically accessible) geminally substituted compounds are extremely high (180 to 250 kJ mol(-1)), the majority of the strain is stored as boat distortions to the phenyl rings in Mes* substituents.

ChemInform Abstract: Poly-Onio Substituted Phosphorus Compounds.

4-Dimethylaminopyridine reacts with phosphorus(III) and (V) halides to give formation or poly-onio substituted polycation salts. Their structures can be assigned on the basis or spectroscopic and analytical data and by anion exchange reactions

Phosphorylation of Thiophenes

This review deals with synthetic methods, chemical transformations, and some physical properties of thienyland benzothienyl substituted phosphorus compounds bearing P-Het or P-CH2-Het bonds. The basic synthetic approaches to these compounds include reactions of metalated thiophenes with phosphorus(III) and (V) halides, phosphorylation of thiophenes in the presence of a mild Lewis acid, use of halogenothiophenes in the Arbuzov reaction, and phosphorylation of thiophenes with phosphorus(III) halides in basic medium. Synthetic approaches to condensed heterocyclic systems of novel types are also considered. Investigation of chemical properties of phosphorylated thiophenes has revealed that, despite the great similarity with phenyl analogues, differences connected to the nature of the heterocycle are observed. The tertiary phosphines bearing at least one thienyl substituent are less active in quaternization and oxidation reactions. At the same time, basic hydrolysis leading to C-P bond cleavage is facilitated, as compared to benzene derivatives. Keywords: Metalated Thiophenes, Phosphorus Tribromide, Friedel-Crafts Reaction, Halogenothiophenes, Arbuzov Reaction, Hydrophosphorylation

Syntheses of phosphorus containing hydrolytically stable multisite receptors

Facile condensation reactions between 4′-formylbenzo-15-crown-5 and tris and hexa-hydrazino substituted phosphorus compounds lead quantitatively to three new polymacrocyclic compounds 3a,b and 5.

Cyanamide Substituted Phosphorus Compounds

Cyanamide Substituted Phosphorus Compounds

Cyanamide Substituted Phosphorus Compounds

Abstract Referring to the field of phosphorus chemistry the fragment N(CN) is discussed as pseudochalcogen.

N,N′,N′-Trimethylethylendiamin-substituierte Phosphor(III)-Verbindungen und deren Oxidation zu Derivaten mit tetra- und pentakoordiniertem Phosphor / N,N′,N′-Trim ethylethylenediamine-Substituted Phosphorus(III) Com pounds and their Oxidation to Derivatives with Four-and Five-Coordinated Phosphorus

A study was made of the intramolecular donor-acceptor interaction in N,N′,N′-trimethylethylenediamine- substituted phosphorus compounds, involving λ3-, λ4- and λ5-phosphorus atoms, as a function of the nature of the substituents at phosphorus. The reaction of N-trimethylsilyl-N,N′,N′-trimethylethylenediamine (1) with (PriO)2PCl furnished the acyclic, trimethylethylenediamine-substituted phosphorus(III) compound 4. There is no NMR spectroscopic evidence for an intramolecular donor-acceptor interaction between the phosphorus atom and the nitrogen atom of the dimethylamino group in 4. The oxidation of the trivalent phosphorus atom in 4 and in the related compound 5 by sulfur, selenium, tetrachloroo- benzoquinone, and hexafluoroacetone led to the corresponding λ4P compounds 6 - 9 and to the λ5P compounds 10 and 11. No intramolecular donor-acceptor interaction could be detected in any of these products. There was no reaction between 5 and elemental tellurium. The reaction products were characterized by NMR spectroscopy, mass spectrometry, and by elemental analysis.

Poly-Onio Substituted Phosphorus Compounds

4-Dimethylaminopyridine reacts with phosphorus(III) and (V) halides to give formation or poly-onio substituted polycation salts. Their structures can be assigned on the basis or spectroscopic and analytical data and by anion exchange reactions

Regio- and Stereoselective Synthesis of Symmetrical and Unsymmetrical 1,3-Diphosphoryl(Phosphonyl, Phosphinyl) Substituted (E)-Propenes

Symmetrical and unsymmetrical 1,3-diphosphoryl substituted (E)-propenes were synthesized by the reaction of 1-acetoxyallyl substituted phosphorus compounds (phosphonates, phosphinates, and phosphine oxides) with O,O-dialkyl phosphonates (O-alkyl- phosphinates, or dialkyl phosphine oxides) and bis(trimethylsilyl) acetamide (BSA) in the presence of nickel(II) chloride as catalyst, or with trivalent phosphorus acid esters (phosphites, phosphonites, and phosphinites) using only nickel(II) chloride as the catalyst

Menthyl Substituted Phosphorus Compounds: Synthesis, Structures and NMR Studies

Abstract Menthyl-substituted phosphorus compounds were synthesized: (R=CH3, C2H5, i-C3H7, t-C4H9, C6H5, L-Men, D-Men; Men=Menthyl) H-1- and C-13-NMR-spectra were treated by one- and two-dimensional methods to obtain stereospecific shift- and coupling-parameters. Problems of chiral, pseudo-chiral, pro-chiral and pseudo-pro-chiral compounds are discussed. Aromatic-ring-current-effects were calculated based on theories of Johnson/Bovey and Haigh/Mallion. Novel computer programs JOBO and HAMA were designed for convenient evaluation of ring-current-effects. The methods are demonstrated comparing Mosher's menthyl- und neo-menthylphosphineoxides L-Men(C6H5)(CH3)PO and neo-Men(C6H5)(CH3)PO R(p) and S(p) configurations. The programs may be obtained from the authors on request.

Molecular connectivity and total response surface optimization

The relation between biological activity and molecular structure may be viewed mathematically as a surface. The maximum or minimum position on the surface is associated with optimum activity and structure parameters. A useful approach to QSAR is to identify the optimum structure and relate it to drug design. Such an approach has been applied to the neurotoxicity of 21 substituted phosphorus compounds using molecular connectivity indexes. Two-variable transformations are used. The first, not directly related to surface optimization, introduces the sum and difference of the first order chi indexes. These transformed variables are shown to represent size and electronic effects, respectively. Using these variables in the full five-variable quadratic expression, excellent statistics are achieved: r = 0.979, s = 0.18, F = 68, n = 21. The second transformation, moving the origin to the surface extremum, reduced the equation to three variables while retaining the high quality statistics. Detailed discussion of interpretation is presented.

Synthesis and reactivity of [bis(trimethylsilyl)methylene]mesitylphosphine

Abstract : Two recent papers have described the synthesis and characterization of a series of P-mesityl substituted phosphorus compounds containing Si-N-P and/or Si-C-P linkages. These systems are of interest, in part, as precursors to new types of low-coordinate phosphorus compounds including (methylene) phosphines, RP-CR2 double bond, and imino (methylene) phosphoranes, RP(-NR)-CR2 double bonds. As an extension of these studies, we report here the synthesis and some derivative reactions of bis(Trimethylsilyl)methylene(mesityl)phosphine.

4452792 Acridine substituted phosphorus compounds and their insecticidal use: James Traxler assigned to Velsicol Chemical Corporation

4452792 Acridine substituted phosphorus compounds and their insecticidal use: James Traxler assigned to Velsicol Chemical Corporation

Synthesis and reactivity of some p-mesityl-substituted phosphorus compounds

Abstract : The preparation and characterization of a series of P-mesityl substituted phosphorus compounds containing the Si-N-P and/or Si-C-P linkages are described. The reaction of RPC12 (R = 2,4,60Me3C6H2) with one equivalent of (Me3Si)2NLi affords the thermally unstable chlorophosphine (Me3Si)2NP(R)Cl (compound 1) in nearly quantitative yield. Substitution reactions of compound 1 are used to prepare the stable derivatives (Me3Si)2NP(R)X (compound 2, X = Me; compound 3, X = H; compound 4, X = CH2SiMe3), while treatment with Me3SiN3 yields the unstable axidophosphine (Me3Si)2NP(R)N3 (compound 5). The methylphosphine compound reacts smoothly with CC14 via elimination of CHCl3 with a (1,3)-silyl shift to form the chlorophosphinimine Me3SiN=P(R) (CH2SiMe3)Cl (compound 6), which is readily converted to the P-Me analogue compound 7 by reaction with MeLi. Depending on the reaction stoichiometry, treatment of RPCl2 with Me3SiCH2MgCl gives either the chlorophosphine Me3SiCH2P(R)Cl (compound 8) as an unstable product from which compound 4 is produced by reaction with (Me3Si)2NLi, or the stable disubstituted phosphine (Me3SiCH2)2PR (compound 9). Decomposition of the azidophosphine compound 5 proceeds with elimination of nitrogen and formation of the dimeric forms of the di(imino)phosphorane RP double bond(NSiMe3)2 (compound 5 a). Either the cis (compound 10) or trans (compound 11) four-membered ring dimer can be isolated under appropriate conditions. Proton, C(13), P(31) NMR data are reported for the new compounds. (Author)

Theory of 31P NMR chemical shifts. II. Bond-angle dependence

Besides other factors contributing to 31P chemical shifts of PX 3 and YPX 3 molecules, the bond angle is specified to be a suitable parameter for explaining detailed variations in these shifts. This is found by using an empirically derived formula of the nuclear magnetic shielding constant σ, namely, σ = na z′ , sin ϕ α sin ϕ β − (−1) Z′ , sin 2 ϕ α , where n is a coefficient referred to the mean excitation energy and assumed to be related to the phosphorus coordination number, Z′ is the number of surrounding electrons at the 31P nucleus in a given molecular species (the electrons taken into account being only those of the atom to which the nucleus belongs), ϕ α and ϕ β are parameters assumed to be dependent on hybridization type and substituent effect, respectively, and a z . represents a factor which multiplied by 2 3 is equivalent to the Lamb formula for a number of electrons equal to Z′. By considering the main possibilities in which the rotation, in liquids or gases, of symmetrically substituted phosphorus compounds can be supposed to occur in an NMR experiment, three distinct equations are derived in order to relate the XPX bond angle φ to the parameter ϕ β . The proposed mathematical scheme leads to a satisfactory agreement between values of φ calculated from 31P chemical-shift data and observed values. It seems also to be consistent with an expected dependence of ϕ gb upon the electronegativity of substituents.