bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereochemistry and some synthetic uses of the heteroarylation of phospholes
Authors: Deschamps Eliane , Ricard Louis , Mathey François 
Published: January 2005

AbstractFurther studies have been conducted on the condensation of electron‐rich arenes or heteroarenes with the dienic system of phosphole P‐complexes. According to the X‐ray crystal structure analysis of one of the resulting 2‐aryl‐3‐phospholene P‐complexes, the condensation takes place on the side of the diene opposite to the complexing group. The decomplexation of the phospholene P–Mo(CO)5 and P–W(CO)5 complexes, respectively, by reaction with sulfur or halogens and tertiary amines yields the corresponding P‐sulfides and oxides with full retention of the stereochemistry at phosphorus. Double condensation of the phosphole P‐complexes onto the 2 and 5 positions of thiophene and furan ultimately leads to phosphole–thiophene–phosphole and phosphole–furan–phosphole chains. The first type has been characterized by X‐ray crystal structure analysis of its P,P‐disulfide. No electronic delocalization appears to take place along the chain.
Trifluoromethyl phosphaalkenes of the type F3CPC(OR)NR2: Synthesis, spectroscopic investigations, and ligand properties [1]
Authors: Grobe Joseph , Van Duc Le , Althoff Ulrike , Krebs Bernt , Dartmann Mechtild , Gleiter Rolf 
Published: January 2005

AbstractThe one‐pot reaction of the alcohol adducts F3CP(H)CF2OR of perfluoro‐2‐phosphapropene with secondary amines in a 1:3 molar ratio affords the stable phosphaalkenes F3CPC(OR)NR2 (R = Me, Et) 1–4 in yields of 58%. NMR and He(I) PE spectroscopic investigations show that the lone pair electrons on nitrogen and oxygen participate in n/π conjugation. In contrast to typical low‐coordinated double bonds the new derivatives do not react with alcohols, amines, and 1,3‐dienes. The derivatives are more closely related to the phosphaalkenes F3C(F)NR2 than to perfluoro‐2‐phosphapropene. The reaction of F3C(OEt)NMe2 (3) with Cr(CO)5THF yields the η1(P) complex Cr(CO)5[F3CPC(OEt)NMe2] (7) with an unusually long sp2 PC bond (1.809 Å).
Theoretical study on the transition state of oxaphosphetane formation between ethylidenetriphenylphosphorane and acetaldehyde
Authors: Yamataka Hiroshi , Hanafusa Terukiyo , Nagase Shigeru , Kurakake Toshiya 
Published: January 2005

AbstractThe MNDO MO calculations were carried out for the formation of oxaphosphetanes from substituted ylides and aldehydes (Equations 2–4). It was found that the reactions proceed through a nearly planar cyclic four‐membered ring transition state (TS) in all cases studied and that phenyl substitution on phosphorus has little effect on the TS geometry. This finding is not in line with the TS models that have been proposed to explain the experimentally observed cis‐selectivity.
Azidophosphanes: Attractive starting materials for the preparation of phosphazenes
Authors: Riesel Lothar , Friebe Robert , Bergemann Anke , Detlef/Sturm  
Published: January 2005

AbstractAzidophosphanes are versatile reactants in the Staudinger reaction. The azides Cl2PN3 (1), (Et2N)ClPN3 (2), and (Et2N)2PN3 (3) react with phosphanes to give the N‐phosphanyl phosphazenes 4–10. (Et2N)P(N3)2 is oxidized by PhN3 yielding (Et2N)P(N3)2NPh (11), which with PPh3 yields the di‐ and triphosphazenes 12 and 13.
The structures of the hypho‐compounds B5H and B6H14: Application of the combined ab initio/IGLO/NMR method
Authors: Bühl Michael , Schleyer Paul Von Ragué , McKee Michael L. 
Published: January 2005

AbstractAb initio and NMR chemical shift (IGLO) calculations on the TZP/MP2/6‐31G* level suggest a Cs (1c), or the closely related C1 (1d) structure, rather than the proposed C2v (1a) geometry for hypho‐B5H12−. The two equivalent Cs forms interconvert rapidly with a barrier of ca 5 kcal/mol. For hypho‐B6H14 (2), at least six isomers examined lie within ca 7 kcal/mol in energy suggesting fluxional behavior, but none of the geometries (including the current proposals in the literature) reproduces the experimental chemical shifts.
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
Authors: Setzer William N. , Brown Milton L. , Wu Chia‐Kuei , Meehan Edward J. 
Published: January 2005

AbstractThe 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) Å, b = 7.6132(8) Å, c = 12.119(2) Å, 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.
Edge inversion in tricoordinated main group IV anions
Authors: Dixon David A. , Arduengo Anthony J. , Lappert Michael F. 
Published: January 2005

AbstractThe inversion barriers for SiF3−, GeF3−, SnF3−, SnCl3−, and SnCl2NH2− have been calculated by ab initio molecular orbital theory with large basis sets and have included the effects of electron correlation. The anions are predicted to invert by the edge inversion process. The edge inversion barriers in kcal/mol are 40.3, 34.3, 27.8, 27.8, and 14.2 in the order given above. Geometric effects and the charge distributions are discussed.
Reaction of thioxophosphorane sulfenyl bromides with ethyl vinyl ether: Mechanistic and synthetic aspects
Authors: Potrzebowski Marek J. , Łopusiński Andrzej , Michalski Jan 
Published: January 2005

AbstractThe mechanistic and synthetic aspects of the addition reaction of thioxophosphorane sulfenyl bromide with ethyl vinyl ether were studied in detail by NMR techniques. It has been found that the regiospecific, primary product of the reaction, 1‐bromo‐1‐ethoxy‐2S(dialkoxythiophosphoryl)ethane I, is unstable and undergoes slow decomposition to give four compounds. The formation of thiophosphoryl derivatives, vinyl ethers II and III, aldehyde IV, and the symmetrical hemiacetal anhydride V, has been considered in terms of a carbocation intermediate. By choice of the appropriate reaction conditions, the aldehyde IV can be obtained in very high yield.
Stereochemistry of the reaction of ribonucleoside cyclic 3′,5′‐phosphorothioates with oxiranes
Authors: Okruszek Andrzej , Guga Piotr , Stec Wojciech J. 
Published: January 2005

AbstractThe stereochemical course of the epoxide‐induced oxidative rearrangement of ribonucleoside cyclic 3′,5′‐phosphorothioates into the corresponding 2′,3′‐phosphates has been determined using styrene [18O] oxide and (Sp)‐uridine cyclic 3′,5′‐phosphorothioate. The evidence of full stereoselectivity of this reaction is presented and mechanistic implications of the presence of the nucleoside 2′‐hydroxyl group are discussed in terms of a classical Hamer Mechanism.
Directed ortho‐lithiation reactions: Position‐specific introduction of tributylstannyl derivative onto β‐[N,N‐dimethylamino]ethoxybenzenes
Authors: El‐Wakil Hoda , Seitz Daved E. , Mansour El‐Sayed M. E. 
Published: January 2005

AbstractThis article presents the position‐specific introduction of substituents onto substituted phenolic rings via electrophilic destannylation of trialkylstannyl derivatives of β‐[N,N‐dialkylamino]ethoxybenzenes.
Recent developments in heterocyclic systems with a Si–M′–Ge or Ge–M′–Ge linkage (M′ = Fe, Ru, or Co)
Authors: Barrau Jacques 
Published: January 2005

AbstractThe present review describes recent work on the synthesis, spectroscopic analysis, and investigation of the chemical behaviors of new polynuclear heterocyclic complexes 1–7 having M–M′–M catenation. Various CO substitution, cleavage, expansion, and adducts decomposition reactions are described.
OAs(NMe2)3: Synthesis and crystal structure of the arsenic analogue of HMPT
Authors: Lorberth JÖRg , Dorn Reiner , Shin Sung‐Hee , Otto Michael , Massa Werner 
Published: January 2005

AbstractOAs(NMe2)3 (HMAsT) is obtained in low yields by reacting OAsCl3 with excess HNMe2 or by ozonolysis of As(NMe2)3; however, it is formed in yields >65% by using (Me3Si)2O2 and As(NMe2)3 in hydrocarbon solution. The structure of HMAsT was established by IR/Raman, NMR and mass spectroscopy, and single crystal X‐ray structure analysis. The structure determination revealed (sp3C)‐H…O–hydrogen bonding in the solid state. Acid‐base reaction by methanolysis affords ionic [Me2NH2] [O2As(OMe)2] while iodide is oxidized to iodine.
Gas phase structure and vibrational spectra of dimethoxysulfane (CH3O)2S
Authors: Baumeister Edgar , Oberhammer Heinz , Schmidt Heinar , Steudel Ralf 
Published: January 2005

AbstractThe vapor phase structure of (CH3O)2S [1] has been investigated by electron diffraction and ab initio MO calculations, which both result in a C2 symmetry for the most stable geometry, the Cs conformer being less stable by about 12 kJ/mol. The torsional barrier for rotation about one SO bond was calculated as 37 kJ/mol (trans barrier). The geometrical parameters (electron diffraction) of the C2 conformer are: dSO = 162.5(2), dCO = 142.6(3), dCH = 110.5(7) pm angles OSO = 103(1)°, SOC = 115.9(4)°, HCH = 109(1)°, torsional angle COSO = 84(3)°. Geometrical data calculated with 6‐31G* basis set agree well with the diffraction data; calculated dipole moments 1.1 D (C2) and 3.3 D (Cs).The infrared spectrum of gaseous (CH3O)2S and the Raman spectra of liquid and solid (CH3O)2S are reported and have been almost fully assigned to the 27 fundamental vibrations.
Phosphonic systems: 5. Prototropic equilibria of diethyl alkenylphosphonates
Authors: Gerber J. P. , Modro T. A. , Wagener C. C. P. , Zwierzak A. 
Published: January 2005

AbstractBase‐catalyzed prototropic equilibria for nine pairs of diethyl 1‐ and 2‐alkenylphosphonates have been determined. The results, together with those reported elsewhere for three other pairs, demonstrated that the diethoxyphosphoryl group PO3Et2 has only a very weakly stabilizing effect on the adjacent carbon–carbon double bond. The decisive factors are the number of carbon atoms attached to the double bond and the number of hydrogen atoms available for hyperconjugation.
First 1‐phospha‐1,3‐dienes unsubstituted in the carbon chain by pyrolysis of diallylphosphines: A novel route to the phosphorus—carbon double bond
Authors: Martin Gonzalo , Ocando‐Mavarez Edgar 
Published: January 2005

AbstractAllylic phosphine systems were studied as phosphorus–carbon double bond precursors. 1‐Phenyl and 1‐butyl‐1‐phospha‐1,3‐dienes were generated by pyrolysis at 350–460°C of the corresponding diallyl phosphines in a stirred‐flow reactor. The unsubstituted phosphadienes generated in this manner dimerized; the formation of [4 + 2] cycloaddition products was confirmed by NMR and mass spectroscopic analysis. 31P NMR data of the 1‐phospha‐1,3‐dienes were obtained.
Theoretical studies on the diazacyclopentadienylidenes: An analysis of aromatic versus nonaromatic systems and singlet versus triplet reactivity
Authors: Pasto Daniel J. 
Published: January 2005

AbstractAb initio molecular orbital calculations have been carried out on the various electronic states of 2,3‐ (6), 2,4‐ (7), 2,5‐ (8), and 3,4‐diazacyclopentadienylidene (9) at the fully geometry optimized 6–31G* level, with single point calculations being carried out at the MP2/6–31G* level. The calculated geometries are interpreted in terms of the degree of occupancy and the nature of the π and σ‐nonbonded MO's. At the 6–31G* level the five π‐electron, π,σ‐triplet states were calculated to be considerably lower in energy. At the MP2/6–31G* level, however, with 7 the six π‐electron singlet state is calculated to lie only slightly above the five π‐electron triplet (0.4 kcal mole−1), whereas with 8 and 9 the aromatic six π‐electron singlet states are calculated to be lower in energy (9.0 and 8.1 kcal mole−1). With 3 and 9 the aromatic six π‐electron σ‐triplet states lie only 3.6 and 5.5 kcal mole−1 above the lowest energy states. It is concluded that, in general, the energy gained by having an electron in a lower energy σ‐type MO instead of a higher energy π MO effectively offsets the energy gained by having an aromatic π system. The results are discussed in terms of the observed chemistry of 6–9 and their substituted systems.
1‐acetoxyvinyl phosphonates: Facile synthesis via catalytic acylation of dialkyl phosphites
Authors: Tyryshkin Nikolay I. , Fuzshenokova Alexandra V. , Vedernikov Andrey N. , Solomonov Boris N. 
Published: January 2005

AbstractA new and facile method of synthesis of 1‐acetoxyvinyl phosphonates (2) has been found. Dialkyl phosphites react readily with acetic anhydride in acetonitrile solution in the presence of catalysts to produce 2 and acylphosphonates (1) as a minor product. The most efficient catalysts are metal compounds of variable valency: iron(II), iron(III), and cobalt(II) chlorides. The same compounds catalyze transformation of 1 into 2 in an acetonitrile solution of acetic anhydride.
Lewis acid properties of phosphenium and arsenium cations: Study of their adducts with pyridine
Authors: Payrastre Corinne , Madaule Yves , Wolf Jean Gérard , Kim Tag Chong , Mazières Marie‐Rose , Wolf Robert , Sanchez Michel 
Published: January 2005

AbstractIn the growing field of dicoordinated Group 15 cations, the quantitative study of the Lewis acid properties of phosphenium or arsenium cations has not yet been undertaken. Moreover, there are only a few described examples of syntheses of arsenium cations. The aim of this work is to enhance this series and to develop a quantitative comparative study of their complexation with Lewis bases such as pyridine. The observation of the 13C NMR C‐4 variation in the pyridine ring is a good probe to obtain the apparent equilibrium constant Kc and thus a Lewis acidity scale. Phosphenium cations are more acidic than arsenium cations.
Gas phase thermolysis of allylphosphines, kinetic study
Authors: Martín G. , Ocando‐Mavarez E. , Osorio A. , Laya M. , Canestrari M. 
Published: January 2005

AbstractDiallylphenyl, allylbenzylphenyl and allylmethylphenyl phosphines were pyrolized in a stirred‐flow reactor at 380–429°C/7‐20 torr, using toluene as carrier gas. The reaction products were propene, 1‐phospha‐1,3‐butadiene, 1‐phospha‐1,2‐diphenylethylene and 1‐phosphaethylene.The phospha‐alkenes formed evolve into cyclo addition products. The propene elimination reaction showed first‐order kinetics with rate coefficients following the Arrhenius equations: Diallylphenylphosphine:
k(s−1) = 1010.57 ± 0.31 exp(‐143 ± 4 kJ/mol.RT)
Allylbenzylphenylphosphine:
k(s−1) = 109.71 ± 0.47 exp(‐135 ± 6 kJ/mol.RT)
Allylbenzylphenylphosphine:
k(s−1) = 109.61 ± 0.61 exp(‐144 ± 9 kJ/mol.RT)
A six‐center cyclic transition state unimolecular reaction mechanism, consistent with the above Arrhenius parameters, is proposed for the propene elimination reaction.
Reaction of lithium diphenylphosphonium di(methylide) with carbonic acid derivatives. A novel access to polyfunctional unsaturated esters and amides
Authors: Cristau Henri‐Jean , Perraud‐Darcy Anne , Ribeill Yves 
Published: January 2005

AbstractThe lithium diphenylphosphonium di(methylide) Ph2 P(CH2)2 Li 1 readily attacks cyclic carbonates, carbamates, and thiocarbamates, resulting in “pseudo‐acylation” products, after a ring‐opening step. Thus, new stabilized ylides are prepared, which can be used in situ as carbonyl olefination reagents towards aldehydes. This procedure is a new one‐pot method for the synthesis of (E)‐vinylic esters and amides, bearing a free ω‐hydroxyl group. When a thiocarbamate is the initial substrate for 1, a Michael‐type cyclization occurs, following the Wittig olefination, resulting in the one‐pot preparation of 7‐membered heterocycles.
Aminophosphaethyne (PCNH2) and its isomers
Authors: Ermolaeva Ludmila , Ionkin Alexey 
Published: January 2005

AbstractThe potential energy hypersurface of the conversion of aminophosphaethyne (1) to 1‐aza‐3‐phosphaallene (2) has been studied with the MNDO method. The interconversion includes five intermediate species. The structure and energy of 1 and its isomers produced by a hydrogen shift have been calculated also with ab initio molecular orbital theory by a split valence basis set including a polarization function at the P atom. The results reveal that all the isomers are equilibrium structures. The ab initio calculation predicts the carbenaazaphosphirane 3 to be the intermediate lowest in energy. It is suggested that a carbene (3), phosphinidene (4) or azaphosphirene (5) are responsible for the 1‐aza‐2,4‐diphosphole formation.
Dialkyltin derivatives of dicarboxylic acids: Synthesis, characterization and in vitro antitumor properties
Authors: Gielen Marcel , Bouâlam Mohammed , Meriem Abdelkader , Mahieu Bernard , Biesemans Monique , Willem Rudolph 
Published: January 2005

AbstractDiorganotin derivatives of dicarboxylic acids, including diethyltin propene‐1,3‐dicarboxylate, diethyltin homophthalate, and di‐n‐butyltin tetrafluorophthalate, were tested in vitro against two human tumor cell lines, MCF‐7, a mammary tumor, and WiDr, a colon carcinoma. Most of these display lower inhibition doses ID50 than cis‐platin. The synthesis and characterization of the last three compounds by Mössbauer spectroscopy, 1H, 13C and/or 119Sn NMR and mass spectrometry, are also presented.
Attempted 1,3‐trimethylsilyl migration in Me3SiPSNR system
Authors: Ionkin A. S. , Ignat'Eva S. N. , Litvinov I. A. , Naumov V. A. , Arbuzov B. A. 
Published: January 2005

AbstractA dimer of thioxo‐N‐t‐butylimino(trimethylsiloxy)‐phosphorane 5 has been prepared by reaction of tris(trimethylsilyl) phosphine with N‐sulfinyl‐N‐tert‐butylamine. The structure of 5 has been confimed by X‐ray analysis data. 1‐Aza‐2‐thia‐3‐phosphaallene 1, thiaphosphaziridine 3, iminophosphine P‐sulfide 4 are postulated as intermediates of the reaction studied.
Synthesis and characterization of the double cluster complexes of [(μ‐RS)(μ‐MeAs)Fe2(CO)6]2—the crystal and molecular structure of [μ‐iPrS)(μ‐MeAs)Fe2(Co)6]2
Authors: Song Li‐Cheng , Hu Qing‐Mei , He Jun‐Lin , Wang Ru‐Ji , Wang Hong‐Gen 
Published: January 2005

AbstractBy the reaction of [(μ‐RS (μ‐CO)Fe2 (CO)6] [Et3NH] with MeAsI2, six new double cluster complexes, [(μ‐RS) (μ‐MeAs)Fe2(CO)6]2 (R = Et, Pr, iPr, Bu, C5H11, Ph), were synthesized. The structure of the iPr analog was determined by single crystal X‐ray diffraction techniques. Crystal data were as follows: monoclinic, P21/n, Z = 4, a = 14.475(4), b = 13.825(3), c = 17.225(5) Å, β = 112.44(2)°, V = 3186 Å3, R = 0.037, and Rw = 0.052.
Reaction of heterocyclic ketene aminals with aryl isothiocyanates and synthesis of sulfur containing heterocycles therefrom
Authors: Huang Zhi‐Tang , Yang Jing‐Kui 
Published: January 2005

AbstractHeterocyclic ketene aminals reacted with aryl isothiocyanates to give products of addition to the β‐carbon. By oxidative cyclization of these addition products by the action of bromine, isothiazole‐fused heterocycles or benzothiazole‐substituted heterocyclic ketene aminals were formed according to the influence of the different substituents.
Generation and characterization of new sulfenate salts via ipso‐substitution of azaheterocyclic sulfoxides
Authors: Furukawa Naomichi , Konno Yasuo , Tsuruoka Masayuki , Ogawa Satoshi 
Published: January 2005

AbstractNew stable sulfenate salts, sodium 2‐pyridinesulfenate 9a and sodium 2‐(3‐trimethylsilyl)pyridinesulfenate 9b, were prepared by the ipso‐substitution reactions of azaheterocyclic sulfoxides (1c/3a and 4a, respectively) with sodium ethoxide or sodium butanethiolate under mild conditions and were characterized by physical and spectroscopic properties. The FT‐IR spectra of compounds 9a and 9b showed characteristic SO absorptions at 870 and 890 cm−1, respectively. These sulfenate salts were converted rapidly to the corresponding sulfinate salts on contact with oxygen. A number of other sulfenates were prepared and trapped by alkylation to give sulfoxides (as were 9a and 9b).
Trinitromethanide and tricyanomethanide salts restricted to C, H, N, and O atoms
Authors: Gunasekaran Ananthakrishnan , Boyer Joseph H. 
Published: January 2005

AbstractTrinitromethane combined with oximes of cyclopentanone, cyclohexanone, and diphenylcyclopropenone and with melamine and two 1,3‐dialkyl‐2,4‐dialkylimino‐1,3‐diazetidines to give simple trinitromethanide salt adducts. Tricyanomethane added to diphenylcyclopropenone oxime to give hydroxylamino‐2,3‐diphenylcyclopropenylium tricyanomethanide.
Alkoxylation of hydridophosphorane. II. Reaction of hydridophosphorane with benzenesulphenic esters
Authors: Liu Lunzu , Li Guowei , Huang Mingzhi , Cao Ruzhen , Zhang Shukui 
Published: January 2005

AbstractThe spirophosphorane 4 underwent reaction with a series of benzene‐sulphenic esters 3 to give the corresponding isolable alkoxyphosphoranes. The reactivities of benzenesulphenic esters 3 in this reaction were seen to be dependent on steric hindrance of the R groups. The yields of alkoxyphosphoranes were influenced by the reaction temperature. The probable mechanism was suggested in terms of experimental observations.
The chemistry and structure of the P(O)NC(O) system. Part 3. Preparation of O,O‐diethyl‐N‐acylphosphoramidates and their reactions with electrophiles
Authors: Bauermeister Sieglinde , Modro Tomasz A. , Zwierzak Andrzej 
Published: January 2005

AbstractSix O, O‐diethyl‐N‐acylphosphoramidates (1a‐f) were synthesized. The reactions of their conjugate bases with haloalkanes were studied. The N/(phosphoryl)O/(carbonyl)O regioselectivity varied greatly, depending on the substrate, the haloalkane, the base, and other reaction conditions. The earlier [17] reaction of N‐formyl substrate 1a that led to the N‐phosphorylated formamidine was extended to other substrates 1. Again, the yields and the selectivity depended strongly on the structure of a substrate.
Simple synthesis of endo‐2‐bromo‐5‐thiabicyclo[2.1.1]hexane
Authors: Block Eric , Naganathan Sriram 
Published: January 2005

AbstractA brief synthesis of endo‐2‐bromo‐5‐thiabicyclo [2.1.1]hexane (9) has been developed involving conversion of 3‐cyclopentenol (6) to 3‐thioacetoxycyclopentene (7), bromination of this giving trans‐1,2‐dibromo‐4‐thioacetoxycyclopentane (8), and treatment of the latter with base. Compound 9 is oxidized to its S‐oxide 10 and S, S‐dioxide 11. Comparative 13C and 1H NMR data are given for 9–11.