Phosphorus Heterocycles Research Articles

Sulfur-Phosphorus and Selenium-Phosphorus Heterocycles -Synthesis and Structure Elucidation by Modern NMR -Techniques

Abstract The cis-trans isomerization of the four-membered heterocycle (MeP(S)S)2 (1), well known as methylperthiophosphonic acid anhydride, has been found to proceed via its eight-membered dimer. This can be concluded from the order of the reaction, the activation parameters, and three intermediates, which were found by DNMR methods to take part in the isomerization process. A new synthetic route to selenium phosphorus heterocycles is offered by the oxidative ring closing reaction of the trimethylsilyl esters of triselenophosphonic acids (6) with bromine or dimethylsulfoxide. The silyl esters have been obtained from the reaction of bis(trimethylsilyl)- organophosphanes with elemental selenium. The structures of the tetraselenadiphosphorinane (MeP(Se)Se2)2 (7) and the triselenadiphospholane MeP(Se) Se2MeP(Se)Se (8) have been elucidated by homonuclear 31P double quantum spectra.

Solid-state conformations of medium-sized-ring phosphorus heterocycles: Preparation and x-ray crystal structure of a benzo-fused 1,3,2-dioxaphosphepane in a twist conformation

The crystal and molecular structure of the benzo-fused seven-membered-ring phosphorus heterocycle, 2-phenyl-2-oxo-5,6-benzo-1,3,2-dioxaphosphepane, has been determined by single-crystal X-ray techniques. The compound crystallizes in the monoclinic space group P21/c with four molecules per unit cell of dimensions a = 13.312(1) A, b = 7.6132(8) A, c = 12.119(2) A, and β = 95.990(9)°. Full-matrix leastsquares refinement led to R = 4.4% and Rw = 5.9%. The conformation adopted by the 1,3,2-dioxaphosphepane ring is a twist with approximate C2 symmetry.

SYNTHESIS AND PROPERTIES OF P,P-DIFLUOROYLIDS

Abstract Ylids containing two fluorine atoms at the phosphorus atom of the P[dbnd]C group were prepared by reaction of trifluorophosphoranes with sterically hindered amides of lithium. The ylid structure was studied by means of NMR spectra and chemical reactions. The ylids add to the multiple P[dbnd]C bond alcohols, phenol, thiophenol, HN3 to form difluorophosphoranes, react with carbonyl compounds by a [2 + 2]-cycloaddition to give four membered phosphorus heterocycles, 2,2-difluoro-1,2Δ5-oxaphosphetanes.

SYNTHESIS OF 8-SUBSTITUTED-16H-DINAPHTHO [2,1-d:1′,2′-g] 1, 3, 2-DIOXAPHOSPHOCIN 8-OXIDES

Abstract A new family of phosphorus heterocycles, namely 8-substituted-16H-dinaphtho[2, 1-d: 1′,2′-g]1, 3, 2- dioxaphosphocin 8-oxides, has been obtained via a synthesis from reaction of bis(2-hydroxy-1-naphthyl)methane with a series of aryl phosphorodichloridates in dry benzene in the presence of triethylamine. NMR analysis of a solution of the title compounds revealed essentially no coupling between the bridged methylene protons and the P atom which suggested the dioxaphosphocin ring may exist in a boat conformation in solution. An X-ray diffraction analysis of a crystal of 8-(2′,3′-dimethylphenoxy)- 16H-dinaphtho[2,1-d:1′,2′-g]1,3,2-dioxaphosphocin 8-oxide does indicate that in the solid state the dioxaphosphocin ring is in a distorted and extended boat-like conformation with the P[dbnd]O and bridged CH2 groups directed away from each other. Electron impact mass spectral analysis confirmed the structures of the esters and showed M+, (M — R)+, and (M – OR)+ ions containing the dioxaphosphocin ring system.

SYNTHESIS AND STRUCTURE OF 1-METHYL-5-t-BUTYL-I-AZA-5-PHOSPHACYCLOOCTANE AND ITS PHOSPHINE SULFIDE

Abstract The eight-membered phosphorus heterocycles ButP(CH2CH2CH2)2NMe 1 and But(S)P(CH2CH2CH2)2NMe 2 have been synthesized by the reaction of ButPC12 with the difunctional Grignard reagent MeN(CH2CH2CH2MgCl)2 and subsequent treatment with elemental sulfur. 2 crystallizes in the monoclinic space group P21/c with the unit cell dimensions a 17.728(5), b 6.674(2),c 11.770(2) Å, β 98.12(2)°, Z = 4. The structure was refined to a final R value of 0.047 for 1761 observed reflections. 2 adopts a twist-boat-chair (TBC) conformation. There is no intramolecular P … N interaction but an unusual intermolecular P[dbnd]S … H contact of 2.854 Å.

Phosphorus Heterocycles. Part I. Synthesis of Thiadiazaphosphol-2-ones and Thiadiazaphophol-2-thiones

The condensatin reaction of 3-(2,4-dichlorophenyl)-4-amino-5-marcapto-1,2,4-triazole with various alkyl dichlorophosphate and alkyl dichlorothiophosphate leading to the formation of fused phosphorus heterocycles was carried out

ChemInform Abstract: Solid‐State Conformations of Medium‐Sized‐Ring Phosphorus Heterocycles: X‐Ray Crystal Structures of Two Norbornene‐Fused 1,3,2‐Dioxaphosphepanes with Equatorially Disposed Substituents on Phosphorus.

AbstractThe seven‐membered‐ring phosphorus heterocycles (Ia) (space group P21/c, Z=4) and (Ib) (P212121, Z=4) are synthesized by equimolar reaction of 5‐norbornene‐endo,endo‐2,3‐dimethanol with phenyl dichlorophosphate or phenylphosphonic dichloride in the presence of NEt3 as diastereomeric mixtures with their cis isomers and separated by preparative HPLC.

From phosphorus heterocycles to phosphorus analogues of unsaturated hydrocarbon&.zsbnd;transition metal π-complexes

From phosphorus heterocycles to phosphorus analogues of unsaturated hydrocarbon&.zsbnd;transition metal π-complexes

SOLID-STATE CONFORMATIONS OF MEDIUM-SIZED-RING PHOSPHORUS HETEROCYCLES: X-RAY CRYSTAL STRUCTURES OF TWO NORBORNENE-FUSED 1,3,2-DIOXAPHOSPHEPANES WITH EQUATORIALLY DISPOSED SUBSTITUENTS ON PHOSPHORUS

Abstract The seven-membered-ring phosphorus heterocycles, frans-5,6-(endo,endo-2′,3′-bicyclo[2.2.1]hept-5′-eno)-2-oxo-2-phenoxy-1,3,2-dioxaphosphepane. trans-1, and trans-5,6-(endo,endo-2′,3′-bicyclo-[2.2.1]hept-5′-eno)-2-oxo-2-phenyl-1,3,2-dioxaphosphepane, trans-2, have been synthesized and the crystal and molecular structures of the compounds determined from single-crystal X-ray studies. Compound trans-1 crystallizes in the monoclinic space group P21/c with four molecules per unit cell of dimensions a=6.275(2) Å. b=19.419(7) Å, c=11.363(2) Å, and β=90.89(2)°. Full-matrix least-squares refinement using 2317 unique reflections having 2.5° ≤ 28 ≤ 49.0° and 1 ≤ 3 σ (1) converged at R=0.0543 and Rw=0.0650. Compound trans-2 crystallizes in the orthorhombic space group P212121 with four molecules per unit cell of dimensions a=9.702(3) Å, b=11.296(4) Å, and c=12.605(4) Å. Full-matrix least-squares refinement using 1862 unique reflections having 4.0° ≤ 20 ≤ 50.0° and 1 ≥ 2.5 σ (I) converged at R=0.040 and Rw =0.036. In both of these structures, the seven-membered ring heterocycle adopts a chair conformation with the substituent on phosphorus equatorial.

Synthesis of Heterocycles Based on α,β-Unsaturated P(III) Derivatives

Abstract A general method of phosphorus heterocycle synthesis has been developed. It is based on the interaction between α,β-ethylene, acetylene P(III) derivatives and reagents, which contain electrophilic and nucleophilic centres in α,β- and α,β-positions, e.g. compounds with activated multiple bonds; β-halogenalcanols and thiols; nitrilimines, nitrilylides as 1,3-dipoles. This process is an unsynchron-ic ionic cycloaddition which begins with the attack of a phosphorus atom to the electrophilic centre of a reagent.

Eight-Membered Phosphorus Heterocycles: Synthesis, Three-Dimensional Structure and Stereoelectronic Effects

Abstract General conclusions on three-dimensional structure of 8-membered phosphorus rings are given in terms of the effects produced by the exo- and endo-cyclic heteroatoms, planar fragments, their number and localization. The role of anomeric effect in determination of exocyclic substituent orientation in 6-, 7-and 8-membered cycles is considered. The influence of stereoelectronic interactions in the conformational behavior as well as further prospects in this expanding field are discussed.

ChemInform Abstract: Reaction of the Diisopropylaminochlorophosphenium Cation with Crotonaldehyde Dimethylhydrazone and Acetone Azine.

AbstractWith a view to extend the methods of phosphorus heterocycle synthesis, the title reactions are investigated.

Synthesis of Heterocycles Based on α,β-Unsaturated P(Iii) Derivatives

Abstract A general method of phosphorus heterocycle synthesis has been developed. It is based on the interaction between α,β-ethylene, acetylene P(III) derivatives and reagents, which contain electrophilic and nucleophilic centres in α,β- and α,β-positions, e.g. compounds with activated multiple bonds; β-halogenalcanols and thiols; nitrilimines, nitrilylides as 1,3-dipoles. This process is an unsynchron-ic ionic cycloaddition which begins with the attack of a phosphorus atom to the electrophilic centre of a reagent.

Triboluminescence of 1,2,5-triphenylphosphole and related compounds

An intense triboluminescence has been observed from crystals of 1,2,5-triphenylphosphole when these are crushed between hard surfaces. It is likely that this luminescence originates from crystal fluorescence from the matches obtained between the solid state photoluminescence, solution photoluminescence, and triboluminescence spectra, and from solid state and solution photoluminescence lifetime measurements. Crystals of this phosphole are non-centrosymmetric, like many organic triboluminescent materials. Other analogous phosphorus heterocycles have been prepared, and these, plus some parallel heterocyclic and hydrocarbon examples, have also been tested. Whilst many of these were strongly photoluminescent, only 1,2-diphenyl-5-p-chlorophenylphosphole and its 1-oxide were also found to be triboluminescent. The previously reported triboluminescence of triphenylphosphine and triphenylphosphine oxide were found to be dependent on crystallizing solvent and/or other factors.

Sulfur Phosphorus Heterocycles RP(S)Snand [RP(S)Sm]2, Synthesis and Dynamic Properties

Abstract Sulfur phosphorus heterocycles of general composition RP(S)Sn and [RP(S)Sm]2 have been synthesized from silyl and stannyl esters of trithiophosphonic acids RP(S)(SEMe3)2 (E = Si, Sn). The phosphorus-31 nucleus has been used as an NMR probe for the study of ring reversal and related dynamic processes. The results obtained, provide insight into the mechanism and energy barrier of the crown reversal of cyclo-octasulfur. Moreover, some of the hetero-cycles show configurational changes at the P atoms as well as reversible oligomerization reactions.

Studies on the Synthesis of Phosphorus Heterocycles I. [1,4,3]Thiazaphosphorino[3,4-b][1,3,2]benzodiazaphosphorine 12-Oxides

N-Substituted isatoic anhydrides 4 react with 2-bromoethylamino hydrobromide in the presence of triethylamine to form oxazolines 6, which are treated with phosphorus trichloride to give a key intermediate 7. Reaction of 7 with phenyl isothiocyanate yields fused phosphorus heterocycles 9. Several methods for preparing compounds 9 and the mechanism of cyclization are discussed.

Halogenierung von Phosphorigsäurederivaten

AbstractDerivatives of phosphorous acids react very quickly with chlorine. The stability of adducts is depend on the groups which are bound on the phosphorus atom. Accordingly a different behaviour was observed by the halogenation of alkyl and aryl phosphites or acyclic and cyclic phosphites or saturated and unsaturated heterocyclic phosphorus compounds.

Synthesis and NMR spectra of 5-dialkylamino-2,2,2,2-tetrafluoro-?5-1,4,2?6-diazaphosphoratqlines

New heterocyclic hexacoordinated phosphorus compounds, namely, 5-dialkylamino-3,3-dialkyl-2, 2, 2, 2-tetrafluoro-Δ5-1,4,2λ6-diazaphosphoratolines, have been synthesized and their1H,19F, and31P NMR spectra have been analyzed.

ChemInform Abstract: Bis‐ and Tris(diazomethyl)phosphanes. New Building Blocks for the Synthesis of Phosphorus Heterocycles.

AbstractTrimethylsilyldiazomethane (I) is lithiated and then coupled with the dichlorophosphines (II) to form the bisdiazomethylphosphanes (III) which cyclize under release of nitrogen to produce the phosphorus heterocycle (IV).

OBTENTION DE β-HYDROXYPHOSTONES PAR THERMOLYSE DES DIHYDROXY-2,3 ALKYL PHOSPHONATES DE DIALKYLE. ETUDES STEREOCHIMIQUES PAR RMN DU1H,31P ET13C

Abstract Novel phosphorus heterocycles, 2-ethoxy-2-oxo-4-hydroxy-1,2-oxaphospholanes, that we have named “β-hydroxyphostones”, have been prepared by thermal intramolecular cyclisation in refluxing dimethyl formamide of 2,3-dihydroxyalkyl diethyl phosphonates. Both diastereomers A and B were so obtained in equimolar amounts with good yields. The stereochemistry of these β-hydroxyphostones was assigned from 1H and 13C NMR data. Possible conformations deduced from 3 J PCCH and 3 J POCC coupling constants were also proposed.