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Showing papers in "Phosphorus Sulfur and Silicon and The Related Elements in 1986"


Journal ArticleDOI
TL;DR: In this article, the synthesis of symmetrical diesters derived from hydroxy methylene diphosphonic acids was described either in one step or via the corresponding α ketophosphonate 1a to 8a.
Abstract: Synthesis of symmetrical diesters derived from hydroxy methylene diphosphonic acids 1 to 8 is described either in one step or via the corresponding α ketophosphonate 1a to 8a. Study of the diphosphonates (1 to 6) → phosphate-phosphonates (1b to 6b) isomerization has been realized. Results related to peculiar cases in connection with nonsymmetrical esters 10, 11, 17 and study of the hydrolysis reaction of diphosphonates are presented.

42 citations


Journal ArticleDOI
TL;DR: In the course of the last 20 years the λ3σ2- and λ 3σ2As-Chemistry has progressed rapidly Compounds, containing σ3As-(p-pππ)-bonds, considered before to be unstable have become the basis of a new and extremely interesting branch of chemistry Cycloadditions to the P˭C and As˭c-bonds are developing rapidly as discussed by the authors.
Abstract: In the course of the last 20 years the λ3σ2- and λ3σ2As-Chemistry has progressed rapidly Compounds, containing λ3P- and σ3As-(p-p)π-bonds, considered before to be unstable have become the basis of a new and extremely interesting branch of chemistry Cycloadditions to the P˭C and As˭C-bonds are developing rapidly at the present time Many new types of compounds have been obtained and many rearrangements have been discovered, which are presented and discussed in this compilation Die Chemie der λ3σ2-Phosphor und λ3σ2-Arsen-Verbindungen befindet sich seit etwa 20 Jahren in sturmischer Entwicklung Verbindungen dieser Elemente mit pπ-pπ-Mehrfachbindungen, die fruher als unbestandig galten, konnen isoliert und untersucht werden Zur Zeit stehen Cycloadditionen an die Mehrfachbindungen im Vordergrund des Interesses Neue Verbindungstypen wurden erhalten und zahlreiche Umlagerungen und Folgereaktionen beobachtet, deren Besonderheiten in der vorliegenden ubersicht behandelt werden

41 citations


Journal ArticleDOI
TL;DR: In this paper, a general synthesis of [4 + 1]-cyclocondensation of a reactive phosphorus(III) compound with an appropriate four-membered chain was proposed.
Abstract: Only a limited number of heterophospholes are known. A general synthesis1 involves the [4 + 1]-cyclocondensation of a reactive phosphorus(III) compound with an appropriate four-membered chain, as in the synthesis of the 2H-1,2,3-diazaphospholes.2 The limiting factor in this case is the poor availability of four-membered chains with the necessary functionality at the ends.

29 citations


Journal ArticleDOI
TL;DR: Kapovits et al. as mentioned in this paper proposed the first organic σ-sulfuranes which have both two polar and longer S[sbnd]O bonds nearly at 180°.
Abstract: Earlier, pentacoordinate phosphorus and sulfur compounds were presumed to be of 3sp3d hybridization.1 However, a three-centered-four-electron bond, called a hypervalent bond by Musher,2 was suggested by Rundle and others3 to be consistent with p-orbitals in the early 1950s. The structure of one such compound, SF4, is shown below. Although the original theoretical treatment of hypervalent structure using three sp2- and a p-orbital was modified slightly by introduction of 3d orbitals into the calculation,4,5 the structural feature of such hypervalent compounds has remained the same. Following two stable sulfuranes, one by Kapovits et al. 6 and another by Martin and his coworkers7, are the first organic σ-sulfuranes which have both two polar and longer S[sbnd]O bonds nearly at 180°. Hypervalent interaction was noticed in the extremely short distance between the neutral divalent sulfenyl sulfur atom and the weakly nucleophilic oxygen atom of nitro group of the following compounds, we prepared for X-r...

27 citations


Journal ArticleDOI
TL;DR: In this article, the structural characterization of PhN(PCl2)2 and m-MeC6H4N (PCl 2)2 in solution by 31P NMR spectroscopy and in the solid by single crystal X-ray analysis is reported.
Abstract: The structural characterization of PhN(PCl2)2 and m-MeC6H4N(PCl2)2 in solution by 31P NMR spectroscopy and of PhN(PCl2)2 in the solid by single crystal X-ray analysis is reported. PhN(PCl2)2 adopts a C2v conformation in the solid, in which the phosphorus lone pair electrons are eclipsed and both trans to the Ph group. The C2v conformation assignment for PhN(PCl2)2 and m-MeC6H4N(PCl2)2 is consistent with the low temperature 31P NMR spectral data. PhN(PCl2)2 crystallizes in space group P21, a=6.360(2) A, b=25.618(11) A, c=7.146(2) A, β=90.62(2) deg, Z=4, with two independent molecules per unit cell. The structure was solved and refined by direct methods to R=0.058 and Rw=0.078 for 671 independent reflections. Mean distances (A) and angles (deg) are: P-Cl, 2.036(13); P - N, 1.69(3);

27 citations


Journal ArticleDOI
TL;DR: Barrans, Malavaud, Majoral and Majoral as mentioned in this paper showed that the two-coordinate phosphorus participates much better in cyclic delocalization than the three-coordinated phosphorus.
Abstract: Only late in the development of heterocycles, phosphorus has been recognized as an effective member of aromatic systems. Here, the two-coordinate phosphorus participates much better in cyclic delocalization than the three-coordinate phosphorus. It contributes one electron to the π-system. To constitute a five-membered 6π phosphorus heterocycle, along with N-, CR-, and eventually more P-members, it thus takes one NR- (or S-) member contributing two electrons. This gives rise to the azaphospholes and thiazaphospholes. Since the first representatives were found in 1970 by Melnikov and Shvetsov-Shilovskii in Moscow, the number of known systems has grown to eight including those with annelated rings. They were prepared primarily in the laboratories of Barrans, Malavaud and Majoral in Toulouse, Issleib in Halle, and our own. We can now present ten more new mono- and bicyclic systems. A review is given of the synthetic routes we employed and investigated. They comprise cyclocondensations and cycloadditi...

23 citations


Journal ArticleDOI
TL;DR: In this article, the synthesis, structure and reactivity of tricoordinated pentavalent phosphorus derivatives with the structure -P are described and a synthese is presented.
Abstract: Synthesis, structure and reactivity of tricoordinated pentavalent phosphorus derivatives with the structure -P are described. La synthese. la structure et la reactivite de derives du phosphore tricoordonne pentavalent possedant la structure -P sont derites.

22 citations


Journal ArticleDOI
TL;DR: In this article, a series of phosphorus(III) compounds was found to have an intramolecular donor-acceptor interaction between NMe2 substituents and phosphorus.
Abstract: The reaction of MeOCH2CH2N(Me)SiMe3, Me2NCH2CH2OSiMe3, and Me2NCH2CH2N(Me)SiMe3 with PCl3. PhPCl2, and Ph2PCl was found to proceed with cleavage of the N[sbnd]Si or O[sbnd]Si bond and formation of the phosphorus(III) compounds, 3 to 8. In this series of, in part, novel phosphorus(III) compounds an intramolecular donor-acceptor interaction between NMe2 substituents and phosphorus has been observed which in the case of the product of the reaction of Me2NCH2CH2N(Me)SiMe3 with PCl3, led to a stable intramolecular complex, , 3a. The reversible formation of an intramolecular complex, as a function of temperature, has been observed for Me2NCH2CH2N(Me)P(Ph)Cl,4 while no evidence for an intramolecular interaction was noted for compounds 5, 6 and 8. For compound 7 which is obtained as a solid an intramolecular interaction between phosphorus and nitrogen seems likely in the solid state but cannot be observed by n.m.r. spectroscopy in solution in CDCl3. A single crystal X-ray structure determination for 3a h...

17 citations


Journal ArticleDOI
TL;DR: The synthesis and reactivity of diverse metallo-phosphines LnM-PR2 (LnM=C5R'5(CO)2 Fe(Ru), C5R5', (CO)3 Mo(W), R'=H. W) via several routes is presented and the structure both in the solid state and in solution described in detail as mentioned in this paper.
Abstract: The synthesis and reactivity of diverse metallo-phosphines LnM—PR2 (LnM=C5R'5(CO)2 Fe(Ru), C5R5', (CO)3 Mo(W), R'=H. Me) is discussed. The generation of the metal—phosphorus double-bonded complexes C5H5 (CO)2M=PR2 (M=Mo. W) via several routes is presented and the structure both in the solid state and in solution described in detail. Examples for the outstanding usefulness of M=P complexes as building blocks in the synthesis of metallacycles. dimetallacycles and clusters are given.

17 citations


Journal ArticleDOI
TL;DR: In this article, the mechanism and stereochemistry of nucleophilic substitution reactions at sulfur (SN-S) are discussed in the light of experimental results obtained in the author's laboratory.
Abstract: The mechanism and stereochemistry of nucleophilic substitution reactions at sulfur (SN-S) are discussed in the light of experimental results obtained in the author's laboratory. The first part of this short review article is devoted to the acid-catalyzed alcoholysis of chiral sulfinates and sulfinamides. In the second part, the results of kinetic studies of the isotopic chloride-chloride exchange reaction in sulfonyl chlorides are presented.

16 citations


Journal ArticleDOI
TL;DR: In this article, N3P3Cl2[O(CH2)3]2 derivatives were isolated, whose NMR spectra suggest, and crystal structures prove, them to represent an example of dispiro / spiro-ansa isomerism, the first of its kind in phosphazene chemistry.
Abstract: From the reaction of N3P3Cl6 with 1,3-dihydroxypropane two isomeric N3P3Cl2[O(CH2)3]2 derivatives were isolated, whose NMR spectra suggest, and crystal structures prove, them to represent an example of dispiro / spiro-ansa isomerism, the first of its kind in phosphazene chemistry. The crystal structures and NMR spectra are discussed. Extension of the work with difunctional reagents is reported.

Journal ArticleDOI
TL;DR: Aminophosphanes RP(NEt2)2 and R2PX (X = Cl, Br) as mentioned in this paper were obtained from alkenyl Grignard compounds RMgX (R = −CH=CH2, as mentioned in this paper.
Abstract: Aminophosphanes RP(NEt2)2 and R2P(NEt2), obtained from alkenyl Grignard compounds RMgX (R =—CH=CH2, —CH2CH=CH2, o(CH2=CH)C6H4—, o(CH2=CHCH2)C6,H4—) and aminochlorophosphanes, reacted smoothly with hydrogen halide to give alkenylhalogenophosphanes RPX2 and R2PX (X = Cl, Br). Properties and reactions of some of these compounds, e.g. with &8 H2O2, H2O and LiAIH4 re reported. On reaction of RPX2 with magnesium only alkenylcyclophosphanes (RP) n were obtained while heterocycles as possible products of an intramolecular reaction of intermediately formed phosphinidenes were not observed. Die aus Alkenylgrignardverbindungen RMgX (R = —CH=CH2, —CH2CH=CH2, o-(CH2=CH)C6H4—, und Aminochlorphosphanen erhaltenen Aminophosphane RP(NEt2)2 und R2 PNEt2 ergebent mit Halogenwassestoff glatt die Halogenphoshane RPX2 und R2 PX (X = Cl, Br). Eigenschaften und Reaktionen einiger dieser Phosphane mit S8, H2O2, H2O und LiAlH4 werden beschrieben. Bei der Umsetzung von RPX2 mit Magnesium bildeten sich ledighch die entsprec...

Journal ArticleDOI
TL;DR: In this article, the synthetic route for phosphorus and sulfonyl-substituted N-imidazoles (triazoles) has been elaborated based on the method proposed by Birkofer8 et al.
Abstract: The synthetic route phosphorus and sulfonyl-substituted N-imidazoles (triazoles) has been elaborated based on the method proposed by Birkofer8 et al The appropriate compounds are obtained in high yield and of analytical purity by the action of N-trimethylsilyl imidazole (triazole) on the corresponding acid chlorides

Journal ArticleDOI
TL;DR: In this article, the main chemical or enzymatic methods of asymmetric oxidation of sulfides are reviewed and a new approach to chiral sulfoxides is described, which uses tertiobutyl hydroperoxide in presence of a chiral titanium complex.
Abstract: The main chemical or enzymatic methods of asymmetric oxidation of sulfides are reviewed. A new approach to chiral sulfoxides is described, which uses tertiobutyl hydroperoxide in presence of a chiral titanium complex. The results obtained during the last two years are summarized. The best enantiomeric excess amounts to 95% in the case of formation of cyclopropyl phenyl sulfoxide.

Journal ArticleDOI
TL;DR: In this paper, a route for the convenient, cost effective synthesis of di-and tri-substituted guanidines from thioureas has been developed.
Abstract: A route for the convenient, cost effective synthesis of di- and tri-substituted guanidines from thioureas has been developed. The key transformation involves activation of the sulfur through S-oxidation followed by displacement of the activated sulfur by an amine nucleophile (oxidation/displacement). This preparation is experimentally facile and results in good isolated yields of desired guanidines. No noxious substances or sensitive intermediates are generated. The reaction time is short and overall yield of desired guanidine from thiourea is good.

Journal ArticleDOI
TL;DR: In this article, the crystal structures of spiro derivatives of cyclotriphosphazatriene are reported and attempts are made to relate these to NMR and other physical properties.
Abstract: The crystal structures of a number of spiro derivatives of cyclotriphosphazatriene are reported. Attempts are made to relate these to NMR and other physical properties.

Journal ArticleDOI
TL;DR: In this article, Thioacetamide, thiotemacetamide S-oxide, and thiopivalamide Soxide (8) were oxidized with H2O2 in H2 18O to generate the corresponding amides with at least 50% 18O incorporation.
Abstract: Thioacetamide, thioacetamide S-oxide (1), and thiopivalamide S-oxide (8) were oxidized with H2O2 in H2 18O to generate the corresponding amides with at least 50% 18O incorporation; hydrolysis of the S-oxides to the amides or 18O exchange with the amides occurs much more slowly. When 1 and trifluorothioacetamide (6) were oxidized with three and four equivalents of H2O2, respectively, in the presence of benzylamine, N-acetylbemylamine (5) and N-benzyltrifluoroacetamide (7) were isolated in respective yields of 17% and 37%. These results are interpreted as evidence for an oxidative desulfurization mechanism involving nucleophilic attack at the carbon atom of an S,S-dioxide or trioxide intermediate as the major pathway; a minor pathway may involve the intermediacy of an oxathiirane S -oxide (3) or dioxide (4) species. Understanding is added to the behavior of S-oxides in aqueous solution, as well as to thermal stability in deuterochloroform. Also reported are studies of the preparation and properties...

Journal ArticleDOI
TL;DR: A systematic study of crystallographic data has revealed a number of correlations between structural parameters, (e.g., bond angles, bond lengths, dihedral angles) and physical and chemical properties in phosphazenes and related compounds as mentioned in this paper.
Abstract: A systematic study of crystallographic data has revealed a number of correlations between structural parameters, (e.g., bond angles, bond lengths, dihedral angles) and physical and chemical properties in phosphazenes and related compounds. These include (a) endocyclic bond angles NPN and PNP and their relationships to group electronegativities; (b) endocyclic bond angles NPN and PNP in geminal cyclotriphosphazatrienes, N3P3RR′X4 (X = F, Cl) and their relationships to basicity; (c) deviations from some relationships due to ring puckering and the use of mathematical techniques to “flatten out” these rings; (d) 35Cl nuclear quadrupole resonance frequencies and P–Cl bond lengths and other relationships; (e) exocyclic bond angles viz. OPO, NPN, ClPCl, CPC etc. versus 31P NMR chemical shifts; (f) ring compression and deformation and unusual mass spectrometric and bulk polymerisation properties; (g) relationships in phosphazenylcyclophosphazenes between crystal structure, 4 J(PP) coupling constants, bas...

Journal ArticleDOI
TL;DR: The S-bridged pentaoxyphosphorane 2a has been prepared for the first time and its ground-state structure studied on the time scale of NMR (1H, 19F, 31P, and 13C) spectroscopic measurements as mentioned in this paper.
Abstract: The S-bridged pentaoxyphosphorane 2a has been prpared for the first time and its ground-state structure studied on the time scale of NMR (1H, 19F, 31P, and 13C) spectroscopic measurements. Compound 2a was found to show significant barriers to intramolecular ligand rearrangement (pseudorotation). A comparative study on non-bridged pentaoxyphosphoranes of type 14 was also undertaken.

Journal ArticleDOI
TL;DR: In this paper, the electrophilic properties of 6H-1,3-thiazine 6-ones were described via a general (4 + 2) cycloaddition reaction, which gave rise to other reaction products resulting from the addition of two or three molecules of ketene according to the nature of the substituents.
Abstract: Novel, diversely substituted 1-thia 3-aza butadienes have been prepared and reacted with ketene or its derivatives. Via a general (4 + 2) cycloaddition reaction, they afford functionalised 6H-1,3-thiazine 6-ones, the electrophilic properties of which are described. This cycloaddition gives rise to other reaction products resulting from the addition of two or three molecules of ketene according to the nature of the substituents.

Journal ArticleDOI
TL;DR: In this article, the syntheses of 25 phosphorylated adamantane derivatives are described and their mass spectra are discussed, and the synthesisation of 25 different derivatives of adamantane is discussed.
Abstract: The syntheses of 25 phosphorylated adamantane derivatives are described and their mass spectra are discussed.

Journal ArticleDOI
TL;DR: Diethoxytriphenylphosphine and diethyl peroxide (DTPP) as mentioned in this paper is a "hydrolytically active" dioxyphosphorane which promotes cyclodehydration of diols to cyclic ethers in neutral media.
Abstract: Diethoxytriphenylphosphorane. DTPP. prepared by reaction of triphenylphosphine and diethyl peroxide. is a “hydrolytically active” dioxyphosphorane which promotes mild and efficient cyclodehydration of diols to cyclic ethers in neutral media. Simple 1,2-, 1,4-, and 1,5-diols afford good yields of the cyclic ethers but 1,3-propanediol and 1,6-hexanediol give mainly 3-ethoxy-1-propanol and 6-ethoxy-1-hexanol. respectively. with DTPP. Tri- and tetra-substituted 1,2-diols afford the relatively stable 1,3,2-dinxaphospholanes in the presence of DTPP and the reaction conditions dictate whether epoxides, ketones, or allylic alcohols are obtained.

Journal ArticleDOI
TL;DR: In this paper, the electronic interaction between the incoming nucleophile and the leaving group is shown to be very deep when they are both in the apical position of a tbp intermediate, and the influence of the nucleophile is minimized when the approach of a nucleophile affords a 90° angle, i.e. overall retention at phosphorus.
Abstract: The stereochemical behavior of functional organosilanes is explained considering electronic factors. The reactivity depends on the stereochemistry. Retention and/or inversion are controlled by a frontier orbital process. The same conclusions can be extended to the mechanism of nucleophilic substitution of halogenophosphorus compounds. The kinetic data show that the electronic interaction between the incoming nucleophile and the leaving group is very deep when they are both in the apical position of a tbp intermediate. By contrast, the influence of the nucleophile is minimized when the approach of the nucleophile affords a 90° angle, i.e. overall retention at phosphorus. The hydrolysis of silicates should be certainly more connected to the process of hydrolysis of phosphates through a mechanism involving pseudorotation of the pentacoordinated intermediates.

Journal ArticleDOI
TL;DR: In this article, four oligothymidylates involving alternating alkylphosphotriester-phosphodiester backbones with the same steric configuration for all the phosphotriesters were synthesized by the method in solution from each pure α and β isomers of each pure 5b or neopentylated 5c dinucleoside.
Abstract: Four oligothymidylates involving alternating alkylphosphotriester-phosphodiester backbones with the same steric configuration for all the phosphotriester groups [(Tp(R)Tp)2(CH2)5Acr 2bα; 2bβ (R = Et); cα, 2cβ (R = Me3C—CH2)] have been synthesized by the phosphotriester method in solution from each pure α and β isomers of the ethylated 5b or neopentylated 5c dinucleoside. This partial esterification of the phosphate groups stabilizes the nucleic acid chain against nucleolytic attack by P 1 and S 1 nucleases. This effect increases with the size of the alkyl groups. It also depends upon the steric configuration of the alkylphosphotriester groups: the β isomers are more resistant to S 1 nuclease than the a isomers. Tetrathymidylates bearing two “neopentyl” groups (Tp(CH,CMe3)Tp)2 (CH2)5Acr 2cα and 2cβ give specific complexes with poly r(A) and the β isomer 2c binds a little stronger than the tetrahymidylate (Tp)n (CH2)5 Acr. The neopentyl group is stable under the conditions required for the synthesi...

Journal ArticleDOI
TL;DR: In this article, the chemical properties of tris(2,4,6-t-butyl)phenyldithb phosphorane (1) were investigated.
Abstract: The chemical properties of the dihometaphosphonate analogue, tris(2,4,6-t-butyl)phenyldithb phosphorane (1), are reported in detail.

Journal ArticleDOI
TL;DR: In this paper, the authors studied both cis and trans oxaphosphetane (OP) intermediates at low temperature using high-field H-1, P-31, and C-13 NMR spectroscopy in various instances.
Abstract: Non-stabilized triphenylphosphorus ylides bearing anionic groups can react with aldehydes to give alkene mixtures anomalously enriched in the E isomer [ref. 7]. To explain this phenomenon, we sought to study both cis and trans oxaphosphetane (OP) intermediates at low temperature. The observation of both intermediates was achieved for the first time by the use of high-field H-1, P-31, and C-13 NMR spectroscopy in various instances. We have monitored some Wittig reactions in detail via NMR-based kinetic measurements of OP's and alkenes. In certain cases, OP's equilibrate, presumably by reaction reversal to aldehyde and ylide, to introduce a measure of thermodynamic control into the Wittig reaction. Thermodynamic control accounts for a large portion of the excess E stereoselectivity observed in going from a triphenyl to trialkyl (i.e., butyl) phosphorus ylide. Quenching experiments with HBr and the deprotonation of erythro and threo beta-hydroxyphosphonium salts are also discussed. Attempts to inves...

Journal ArticleDOI
TL;DR: In this paper, the reactions of geminal N3P3Ph2Cl4 with difunctional reagents have been investigated and the N.M.R. spectra of the derivatives are reported.
Abstract: The reactions of geminal N3P3Ph2Cl4 and N3P3(NHBut)2Cl4 with difunctional reagents have been investigated. The N.M.R. spectra of the derivatives are reported. The basicity of these products in nitrobenzene solution is reported and the basicity substituent constants evaluated. X-ray crystallographic data are presented.

Journal ArticleDOI
TL;DR: In this paper, the reactions of N3P3Cl6 with a variety of difunctional reagents are discussed and NMR spectroscopic and X-ray crystallographic investigations are presented.
Abstract: The reactions of N3P3Cl6 with a variety of difunctional reagents are discussed. NMR spectroscopic and X-ray crystallographic investigations are presented.

Journal ArticleDOI
TL;DR: In this article, a mechanism for the conversion of 1 into 3 is proposed, where the bis-N,N-dimethylsulfonamide and bis-acetone hydrazone are identified by micro-analytical and spectral data.
Abstract: Benzalacetone 1 with an excess of chlorosulfonic acid did not give the expected 4, ω-disulfonyl dichloride 2, but 4,β-dichlorosulfonylstyrene 3, which was identified by microanalytical and spectral data, and characterised as the bis-N,N-dimethylsulfonamide 4 and the bis-acetone hydrazone 5. A mechanism for the conversion of 1 into 3 is proposed.

Journal ArticleDOI
TL;DR: In this article, the ground state structures of some isomers of Si6H6 have been calculated using local pseudopotentials, and the cyclic hexasilabenzene (D6h symmetry) is found to be the energetically lowest structure.
Abstract: The method of local pseudopotentials is applied to the calculation of the ground state structures of some isomers of Si6H6. The cyclic hexasilabenzene (D6h symmetry) is found to be the energetically lowest structure. The question of resonance stabilization is discussed.