Showing papers in "Phosphorus Sulfur and Silicon and The Related Elements in 1977"

On the phosphorus-31 chemical shifts of substituted triarylphosphines

Abstract: The 31P chemical shifts of eleven (4-ZC6H4)3P compounds show a slight correlation with the Hammet [sgrave]para constant of Z. The unusually large upfield chemical shifts of (2-ZC6H4)3P compounds are attributed to an extreme “gamma” effect caused by the restricted conformations due to the steric influence of the ortho substituents. Chemical shifts are given for about thirty triarylphosphines, and group contributions to phosphine chemical shifts are listed for twenty-one aryl groups.

Aromatic phosphorus heterocycles

Abstract: In 1967 we synthesized the first phosphabenzene with tervalent P, coordination number 2, and a 3pπ-2pπ-P[dbnd]C-double bond: the 2,4,6-triphenylderivative.1 One of the challenging problems in synthetic organic chemistry - is it possible to replace in the benzene molecule one of the carbon atoms by a second or third row element, by Si, P, As; is it possible to synthesize - against the classical octet rule - Phospha-, Arsa- or Sila-benzenes, had been solved in principle for the element P. This first synthesis was carried out by reaction of pyrylium salts with P (CH2 OH)3 in refluxing pyridine (Fig. 1).

ZUR KENNTNIS DER ORGANOPHOSPHORVERBINDUNGEN, XVII1 Dithiophosphinsäuren RR'P(S)SH, Ihre Synthese, Derivate und Metallkomplexe

Abstract: A wide range of dithiophosphinic acids RR'P(S)SH with different organogroups was obtained in good yields by nucleophilic fission of perthiophosphonic anhydrids (RPS2)2 with Grignard reagents R'MgX. Some reactions, derivatives and metal complexes [RR'P(S)S] M/n of these acids, which are useful intermediates for the synthesis of chiral organophosphorus compounds, are reported. Eine Vielzahl von Dithiophosphinsauren RR'P(S)SH mit unterschiedlichen Organoresten konnte in guter Ausbeute durch nukleophile Spalung von Perthiophosphonsaureanhydriden (RPS2)2 mit Grignardverbindungen R'MgX dargestellt werden. Einige Reaktionen, Derivate und Metallkomplexe [RR'P(S)S] M/n dieser Sauren, die fur die Synthese chiraler Organophosphorverbindungen von Interesse sind, werden beschrieben.

ALKALI-PHOSPHORVERBINDUNGEN UND IHR REAKTIVES VERHALTEN LXXIV Synthese und Reaktionsverhalten von Alkylen-bis-alkylphosphinen

Abstract: Alkylen-bis-phosphine H2P-(CH2)nPH2 (n=2, 3, 4) lassen sich unter geeigneten Bedingungen zu H(M)P-(CH2 n- PH2 und H(M)P-(CH2)n-P(M)H metallieren und nach Umsatz mit Alkylhalogeniden in die entsprechenden Phosphine HRP-(CH2)n-PH2 sowie HRP-(CH2)n-PRH uberfuhren. Letztere sowie deren Alkaliphosphide sind Ausgangabasis fur die Synthese von P-E-P-Heterocyclen (E=Mg, C, Si, Ge) mit 5, 6 und 7-Ringstruktur. Der Reaktionsverlauf zwischen BuLiP-(CH2)3-PLiBu und CH2C12 wird diskutiert. Die Struktur der dargestellten Verbindungen wird NMR- und massenspektrokopisch gesichert. The metallation of alkylen-bis-phosphines H2P-(CH2)nPH2 (n=2, 3, 4) under suitable conditions leads to H(M)P-(CH2)n-PH2 and H(M)P-(CH2)n-P(M)H which reacts with alkylhalides forming the corresponding phosphines. The latter and their alkaliphosphides, respectively, are suitable materials to prepare P-E-P-heterocycles (E=Mg, C, Si, Ge) of 5, 6 and 7-ring structure. The structure of the synthesized compounds is elucidated by investigation...

The crystal and molecular structure of benzyl (2-methoxyphenyl)-diphenylphosphonium bromide

Abstract: The crystal structure of benzyl(2-methoxyphenyl)diphenylphosphonium bromide has been determined from three dimensional X-ray data collected on a three circle diffractometer using MoKα radiation. The salt crystallized in the orthorhombic space group Pbca with cell constants α=15.528 (7), b=16.892 (7), and c=17.921 (8) A. The observed and calculated densities for 8 molecules per unit cell are 1.308 (5) and 1.309 g · cm−3 respectively. The structure was refined by full matrix least squares to final residuals of R=0.089 and R w0.120 for the 1757 independent reflections in the range 2° > 2θ> 42° whose intensities were above background. The cation has near tetrahedral geometry with an average P-C bond distance of 1.819 (14) A and the configuration of the ion is such that the oxygen atom of the methoxy group is trans to the alkyl carbon atom of the benzyl group. The phosphorus-oxygen distance of 2.878 (12) A suggests a weak bonding interaction and qualitative support for this view is obtained from energ...

SYNTHESIS AND THERMAL REARRANGEMENT OF 2-ALKOXYCARBONYL-3-ALKYL-4H-BENZO[b][1,4]THIAZINES

Abstract: The title compounds (4b-d) together with the benzothiazolines (5b-d) have been obtained by a reaction between 2,2′-dithiodianiline (1) and β-keto esters (2b-d). The reaction between 1 and the β-keto ester 2a gives 1,4-benzothiazine 3a in addition to the benzothiazoline 5a. It has been established that the 1,4-benzothaizines 4b-d undergo an acid-catalysed thermal rearrangement involving a [1,3] shift of the sulfur atom, giving rise to the isomeric 1,4-benzothiazines 3b-d.

Structure, stereochemistry, and mechanism of formation of n-acylsulfilimines

Abstract: The methods for the preparation of sulfilimines are summarized, and the stereochemistry and electronic structure of N-acylsulfilmines are discussed. Sulfilimines have a non-planar structure, but the SIV[sbnd]N bond character cannot be determined from their resolvability. N-Sulfonylsulfilimines (RR'SNSO2Q) contain a delocalized SIVNSVI d bond system, the SIVN and SVIn bonds are of intermediate bond order. SIV[sbnd]CH3 hyperconjugation causes strong bond shortening. An asymmetric conformation of a sulfilimine containing two identical SIV substituents was found in the crystalline state which could be accounted for theoretically. The rotation of the SN bond is not restricted in solution. The structure of N-carboacylsulfilimines (RR'SNCOQ) is strongly polar due to the strong NCO conjugation, and the instability of these compounds can be ascribed to the polar structure. The reaction between thioethers and chloramine-T is a nucleophilic substitution; the rate of the reaction is influenced by the nucleop...

Comparative reactivities of alkyl selenosulfates (seleno-bunte salts) and alkyl thiosulfates (bunte salts) with cysteine

Abstract: The comparative reactivities towards cysteine (CySH) of potassium benzyl selenosulfate, potassium p-nitrobenzyl selenosulfate and their thiosulfate isologues have been examined in neutral and slightly acidic media. The selenosulfates (RSeSO− 3) reacted more rapidly and gave better yields of products than the thiosulfates (RSSO− 3) at pH 5 and pH 7 and in each series p-nitrobenzyl derivatives reacted more completely than the benzyl. The products from both types of compound were the cysteine derivatives RX–SCy and CyS–SO− 3 together with the symmetrical diselenides/disulfides RXXR (X = S or Se). In each class of compound the p-nitrobenzyl derivatives produced a greater percentage of RXXR, at the expense of RX–SCy. The nature and distribution of products indicated that several competing reactions were proceeding simultaneously. An investigation of mechanistic possibilities by way of model systems suggested that, in the case of the selenosulfates, the initial products were RSe–SCy plus SO2- 3 which r...

ÜBER PHOSPHAZO-VERBINDUNGEN AUS NITRILEN V.1 DIE REAKTIONEN VON ACETONITRIL, PHENYLACETONITRIL UND MALONSÄUREDINITRIL MIT [C13P[dbnd]N[sbnd]PC13]C1

Abstract: Acetonitrile reacts with P2NC17 to give a mixture of the ring compounds CC1[dbnd]CC1[sbnd]N[sbnd]PC12[sbnd]N[dbnd]PC12 (1) and CC[dbnd]CC1[sbnd]N[sbnd]PC12[sbnd]N[dbnd]PC12 (2), phenyl acetonitrile to give C(C6H5)[dbnd]CC1[sbnd]N[dbnd]PC12[sbnd]N[dbnd]PC12 (3). Malonic acid dinitrile and P2NC17 in dichloroethane yield a mixture of the ring compound C(CN)[dbnd]CC1[sbnd]N[dbnd]PC12[sbnd]N[dbnd]PC12 (4) and the chain compound PC13[dbnd]N[sbnd]PC12[dbnd]N[sbnd]CC1[dbnd]CH[sbnd]CN (5), while the latter compound is exclusively formed when the reaction is carried out in PC13. Preparation, nmr and mass spectra of the new compound are described and discussed. Acetonitrile reacts with P2NC17 zu einem Gemisch der ringformigen Verbindungen CC1[dbnd]CC1[sbnd]N[sbnd]PC12[sbnd]N[dbnd]PC12 (1) und CC[dbnd]CC1[sbnd]N[sbnd]PC12[sbnd]N[dbnd]PC12 (2), Phenylacetonitril zu C(C6H5)[dbnd]CC1[sbnd]N[dbnd]PC12[sbnd]N[dbnd]PC12 (3). Aus Malonsauredinitril und P2NC17 entsteht in Dichlorathan ein Gemisch des Heterocyclus C(...

Über die addition von halogenen und interhalogenverbindungen an vinylphosphonsäurediisopropylester

Abstract: Halogene (Cl2, Br2) und Interhalogenverbindungen (ClBr, ClJ, BrJ) addieren an Vinylphosphonsaurediisopropylester zu den 1,2-Dihalogenathanphosphonsaurediisopropylestern. Anti-Markovnikoff Addition wird nachgewiesen. Durch Dehydrohalogenierung der 1,2-Dihalogenaddukte entstehen 1-Halogenvinylphosphonsaurediisopropylester. Ergebnisse von 60 und 270 MHz 1H NMR Spektralanalysen werden mitgeteilt. Addition of halogens (Cl2, Br2) and interhalogen compounds (ClBr, ClJ, BrJ) to vinylphosphonic acid diisopropylester leads to 1,2-dihalogenoethane phosphonic acid diisopropylesters. Addition in anti-Markovnikoff-sense is derived. Dehydrohalogenation of 1,2-dihalogenoadducts yields 1-halogenovinyl phosphonic acid diisopropylesters. Results of 60 and 270 MHz 1H nmr spectral analysis are given.

Some monocyclic and spirocyclic fluorophosphoranes containing 6- and 7-membered rings

Abstract: The reaction of 2,2-dimethyl-(1,8-naphtho[c,d])-1,3,2-dioxysilenin (3) and 2,2-dimethyldibenzo-1,3,2-dioxysilepin (4) with (C6H5)2PF3 gave the expected monocyclic fluorophosphoranes. Reaction of the same siloxy compounds with PF5 gave products which could not be purified but whose 19F nmr spectra suggested that the desired spirocyclic compounds were present in the impure products. Reaction of the siloxy compounds with C6H5PF4 did not yield identifiable products. The 19F nmr spectra of the products obtained are discussed and structures are tentatively assigned.

Structure sterique des composes cycliques du phosphore. xiii. etude par moment dipolaire des oxo-2 et thio-2 perhydro oxazaphosphorines-1,3,2

Abstract: L'etude par moment dipolaire de la conformation de huit perhydro oxazaphosphorines-1,3,2 est decrite The conformation of eight perhydro 1,3,2-oxazaphosphorines is studied by means of dipole moments

Telomerisation par catalyse redox ix addition de telogenes phosphores sur des composes possedant deux doubles liaisons non conjuguees

Abstract: The synthesis of telechelic oligomers with phosphorated end groups was realized by redox catalysis telomerization reaction by addition of phosphorated telogens containing a trichloromethyl group on monomers with two non-conjugated double bonds. Nous effectuons la synthese d'oligomeres telecheliques a extremites phosphorees en additionnant au moyen de la reaction de telomerisation par catalyse Redox des telogenes phosphores renfernant le groupement trichloromethyle, sur des monomeres a deux doubles liaisons non conjuguees.

STERIC CONTROL OF THE P-CHIRAL GROUP IN GRIGNARD ADDITION TO THE CARBONYL GROUP OF α - KETOPHOSPHINE OXIDE

Abstract: 1,2-Asymmetric inductions in Grignard addition to the carbonyl group of α-keto P-chiral phosphine oxides have been investigated. The favoured reaction product erythro-, 6, is thermodynamically less stable than the threo isomer. This seems to be the first stereochemical evidence of the reversible character of reaction addition of sec-phosphine oxides to the carbonyl group.

Stereochemical properties of the 1-chloro-1- phenyl-2,5-dimethyl-2-phospholenium ion and derived oxide and phosphine

Abstract: The cycloaddition of phenylphosphonous dichloride and trans, trans-2,4-hexadiene, or the addition of chlorine to trans-1-phenyl-cis-2,5-dimethyl-3-phospholene, gave 1-chloro-1-phenyl-2,5-dimethyl-2-phospholenium chloride. This compound shows no evidence in its 31P and 1H nmr spectra for the existence of cis, trans isomers, yet on hydrolysis or dehalogenation with magnesium the resulting oxide and phosphine, respectively, are seen to be isomer mixtures. This phenomenon is explained by a rapid equilibration of the cis, trans form of the I-chloro ion through a pentacovalent species. Structures of the oxides and phosphines were assigned by 1H and 13C nmr relations. The 1-phenyl-cis-2,5-dimethyl-3-phospholenium ion and related compounds were also characterized.

Hydrogen bonding between tertiary phosphines and alcohols

Abstract: The hydrogen bond between several alcohols, in particular benzyl alcohol and isopropanol, as donors, and a number of tertiary phosphines, as well as a smaller number of tertiary arsines, as acceptors was investigated by means of ir spectroscopy in the temperature range +40° to -20°C. Toluene was used as a solvent. The equilibrium constant K, the hydrogen bond enthalpy -ΔH and the entropy -ΔS were determined. The equilibrium constants as well as the -ΔH values are essentially dependent on the basicity of the phosphines. There is no evidence of any steric influence. In the systems with aliphatic phosphines, the highest equilibrium constants are about 20, the lowest values are near unity. Aromatic phosphines possess a lower affinity of interaction with the alcohols. -ΔH varies for the different systems between 1.2 and 3.5 kcalμmole−1. Investigating the acceptor power of arsines we found both K and -ΔH one order of magnitude lower than in the case of phosphines.

The crystal structures of two imino-1,2,4- dithiazoles formed by thermal decomposition of 5-(dialkylamino)-3-(substituted imino)-1,2,4-dithiazoles

Abstract: The thermal decomposition products of two substituted imino-1,2,4-dithiazoles have been studied by single crystal x-ray analysis Both products crystallize in space group P21/c with four molecules per unit cell The first product, obtained from 5-(dimethylamino)-3-(methylimino)-1,2,4-dithiazole has cell dimensions of a=9922(8) A, b=12052(11) A, c=13358(12) A and β=1049(1)° The molecule is made up of two planar segments related by an extremely large twist (−154°) about a C[dbnd]N double bond The results from this study have also contributed further information in the area of nonbonded interactions between ring and thione sulfur atoms The second product, from 5-(dimethylamino)-3(phenylimino)-1,2,4-dithiazole was shown to be an ordered 1:1 complex of the starting material and one of its isomers The cell dimensions are a=12420(6) A, b=8840(9) A, c=22276(22) A and β= 1122(1)° The different molecules are linked by an inter molecular NH… N hydrogen bond

On the electronic structure of diphenyl-sulfdiimide

Abstract: Diphenyl-sulfdiimide (1) absorbs at considerably longer wavelengths than the isomeric diphenyl-diazosulfide (2). This conspicuous UV-VIS-spectral feature has been examined within the framework of the semi-empirical PPP-method. An explanation could be achieved without taking into account the d orbital expansion of sulfur. “Molecules in molecule”-type calculations revealed the significance of the mixing of the locally excited configurations of the heteroatomic groups with charge transfer configurations. For comparison the spectral data of monophenyl-sulfdiimide (3) and N-sulfinyl-aniline (4) are discussed.

Carbodiimide-mediated esterifications and condensations of phosphoric acids dissolved in various alcohols

Abstract: Carbodiimide-mediated phosphorylations carried out with ortho-, pyro-, trimeta-, tetrameta-, and long-chain polyphosphoric acids dissolved in various alcohols, with and without an excess of tri-n-butylamine at 27° were found to consist of complicated reaction sequences involving various phosphoric acids, then esters and complexes formed between the carbodiimide and these acids or esters. In the case of the condensation of orthophosphoric acid, the process of stepwise esterification is seen to compete with the process of condensation to form condensed phosphoric acids and their esters. In general, esterification as opposed to condensation is promoted by (a) increased acidity, (b) smaller size, and (c) increased concentration of the alcohol, as well as by (d) increased concentration of dissociable protons in the solution. 31P chemical-shift data are given for ortho, chain, and ring phosphoric acids and their esters dissolved in the corresponding alcohol. Typical kinetic curves and the distribution ...

1,2-aryl migration and experimental evidence for a two-step mechanism in the electrophilic addition of benzenesulfenyl chloride to olefinic systems

Abstract: Reactions of 2-methyl-3-arylbut-1-en-3-ols (VIII) with benzenesulfenyl chloride were found to give both normal adducts (IX and X) and 1,2-rearrangement products (ketones XI). Yields of XI depend on the electron-releasing effect of the substituents in the benzene ring of VIII. Fairly good correlation of the rate constants with ω° are found, resulting in a ρ ω° equal to -0.83. Tetraethylammonium and especially lithium perchlorate addition were found to lead to a sharp increase in the quantity of the rearrangement products (XI). Solvolysis of the adducts IX and X produced enhanced yields of XI as compared with the addition reactions. These facts are clearly consistent with (i) the occurrence of a 1,2-aryl migration in the fast non-limiting step and (ii) suggest a two-step mechanism involving an intermediate with a low degree of positive charge development at the carbon atoms in the rate-determining step.

Oxygen exchange and racemization reactions of diaryl sulfoxides in sulfuric acid in the presence of potassium chloride

Abstract: The mechanism of the concurrent oxygen exchange and racemization reactions of sulfoxides with chloride ion in sulfuric acid 64.7–80.2% has been studied. We have found that the rate of oxygen exchange of 18O-labeled and optically active phenyl p-tolyl sulfoxide becomes identical to that of racemization by the addition of at least 0.08 mol/l potassium chloride to sulfuric acid media. The rate of the racemization cannot be correlated with H A, and the steric effect of substituent is not very large. Based on these observations, a mechanism (Scheme II) which does not include the rate-limiting formation of the chlorosulfonium ion intermediate may be suggested as most plausible for the reaction.

INFLUENCE OF WATER VAPOR ON P3O3 9- RING OPENING DURING THE THERMAL DEHYDRATION OF NaCaP3O9,3H2O

Abstract: The study of the heterogeneous system NaCaP3O9,3H2O-H2O(g) allowed the internal hydrolysis of P3O3 9 rings to be shown, which explains its instability. In the absence of water vapor pressure, NaCaP3O9,3H2O loses its 3H2O's reversibly.

Vier- und fünfgliedrige phosphorheterocyclen, xvi 1.3.4.2λ3-oxadiazaphospholine

Abstract: Die Kondensation von N 1-substituierten N-Acetyl-und-Benzoyl-hydrazinen mit P[N(CH3)2]3 oder CH3P[NCH3)2]2 fuhrt stets zu 3-substituierten 1.3.4.2Λ3-Oxadizaphospholinen, auch wenn der jeweilige Substituent die Bildung von anderen isomeren Funfringen oder von Isomeren mit groserem Ring oder eine weitergehende Kondensation zuliese. Sie konnen in die 2.2-Dichloro- und 2-Thioxo-1.3.4.2Λ5-Oxadiazaphospholine ubergefuhrt werden. Condensation of N 1-substituted N-acetyl and N-benzoyl hydrazines with P[N(CH3)2]3 or CH3P[N(CH3)2] 2 always gives 3-substituted 1.3.4.2Λ3-oxadiazaphospholines, even if the substituent would allow other isomeric five membered or larger ring phosphorus heterocycles to be formed, or the condensation to proceed further. The title compounds can be oxidized to 2.2-dichloro and 2-thioxo 1.3.4.2Λ5-oxadiazaphospholines.

Phosphine sulphides and their complexes with metals: 13c nmr spectroscopy

Abstract: 13C nuclear magnetic resonance data have been recorded for twenty-two tertiary phosphine sulphides. A discussion of the variation in chemical shifts and 31P−13C coupling constants and a comparison of the data with some analogous phosphine oxides are included. The results are examined with respect to a description of the phosphoryl and thiophosphoryl bonds. The 13C and 1H nmr and infra-red spectra of four gold (I) and aluminium (III) complexes of phosphine sulphides are recorded and commented upon.

Electron impact studies on nitroaroylthiophenes

Abstract: A comparative electron impact study on 2-(2′-nitrobenzoyl)thiophene1(1), 2-(2′-nitrobenzoyl)-3-methylthiophene2(2) and the corresponding 4′-nitrobenzoyl derivatives (3 and 4)3,4 is presented. The results suggest that the presence of nitro group β-to the carbonyl affects the general fragmentation pattern recorded in the literature for 2-acyl and 2-aroylthiophenes.

Preparation of phosphoranes from trivalent phosphorus compounds and 1,2-dioxane

Abstract: 1,2-Dioxane has been allowed to react with a variety of trivalent phosphorus compounds. In some cases pentacoordinate phosphorus compounds were formed, whereas in others tetrahydrofuran and the appropriate phosphoryl containing compound were produced. The mechanism of the reaction is discussed.

Mixed anhydrides of dialkylphosphinous acids and dialkyl hydrogen phosphites, and the isomeric monoxides

Abstract: The three isomers possible for oxidized 1,1-dialkyl-2,2-dialkoxydiphosphines, R2(O)P–P(OR')2 1, R2P–O–P(OR')2 2, and R2P–P(O)(OR')2 3, have been synthesized. Irreversible transformations of 1 to 2 and 2 to 3 have been found and the rearrangement patterns, the role of electrophilic and nucleophilic catalysts are discussed. The fact that 3 is more stable than 1 is attributed to higher donor activity of the ligands attached to the four-coordinate phosphorus in 3. Acid chlorides have been shown to attack the phosphorus atom of ambident anions of trivalent phosphorus acids (the products are 1 and 3) whereas the acids proper react with the acid halides at the oxygen atom, to give 2.

A 19F NMR STUDY OF THE HYDROLYSIS OF ORGANOPHOSPHORUS FLUORIDATES IN AQUEOUS SOLUTION Doubling of the 19F nmr in Diastereoisomeric Mixtures

Abstract: 1H and 19F nmr spectra of two series of organophosphorus esters containing a P–F bond were studied. 2-Fluoro-4-methyl 1,3,2-dioxaphosphorinane 2-oxide (2) was found to be a mixture of two diastereoisomers in the ratio of trans/cis = 4. Stereospecific catalysis of phosphate and maleate anions in the hydrolysis of 2 was observed, leading to enrichment of the non-hydrolysed fluoridates with the trans isomer. The 19F nmr spectra of O-2-butyl methylphosphonofluoridate (7) and O-pinacolyl methylphosphonofluoridate (8), showed doubling of the 19F nmr spectra, giving rise to two sets of double quartets of equal intensity. 1:1 mixtures of diastereoisomers account for the doubling of the resonance rather than sterically hindered rotation. The applicability of nmr spectroscopy to the study of stereospecific displacement reactions at tetrahedral phosphorus is discussed.

Mutarotation arising from stereolabile pentacoordinated phosphorus

Abstract: The purpose of this paper is to show that optical rotation is a convenient method for studying the intramolecular stereolability in pentacoordinated species, particularly phosphorus derivatives. In chemistry, it is difficult to present a completely new idea and we will deal with this topic under several headings.

Nucleophilic substitution of hexabromobenzene with thiolate anions

Abstract: Reaction of hexabromobenzene with methane- and ethanethiolate gave substitution and protodebromination products.