Showing papers in "Phosphorus Sulfur and Silicon and The Related Elements in 1988"

Phospholipid hydroperoxide glutathione peroxidase

Abstract: “Phospholipid Hydroperoxide Glutathione Peroxidase” (PHGPX) is a new selenoenzyme recently identified and purified from mammalian tissues that reduces membrane hydroperoxides. This monomeric enzyme (M.W. 21,000), different from all previously known glutathione peroxidases and glutathione transferases, has been purified from different mammalian tissues and accounts for the cytosolic inhibition of microsomal lipid peroxidation induced by NADPH or ascorbate and iron. A selenocysteine is present at the active site, as suggested by the kinetics of the inhibition in the presence of iodoacetate. The kinetics, as in the case of GPX, is compatible with a ter-uni ping pong mechanism. The kinetic comparison between PHGPX and GPX in the presence of different substrates and detergents, indicates that, while GPX is more active on soluble hydrophilic substrates, PHGPX is more active on the hydroperoxides in the membranes.

Reactions with hydrazidoyl halides ii [1]: synthesis and reactions of 2-bromothienylglyoxal-2-phenylhydrazone

Abstract: 2-Bromoacetylthiophene reacted with dimethylsulfide in ethanol to afford dimethylsulfonium bromide 2, which reacted with N-nitrosoacetanilide to give 2-bromo-thienylglyoxal-2-phenylhydrazone (3). 3 reacted with pyridine and with triphenylphosphine to give 4a and 4b, respectively. 3 reacted also with morpholine, sodium thiophenolate or potassium cyanide to afford the corresponding hydrazones 5a–c, respectively. 3 reacted also with potassium thiocyanate and with potassium selenocyanate to give the thiadiazoline 6a and selenadiazoline 6b. 3 is utilized also for the synthesis of several heterocycles via its reactions with malononitrile, benzoylacetonitrile, dibenzoylmethane, ω-benzenesulfonylacetophenone, N-arylmaleimides and benzalaniline. Structural assignments have been made on the basis of elemental analyses, spectral data and independent synthesis wherever possible.

Synthesis of enantiomerically pure aminophosphonic acids

Abstract: An efficient general asymmetric synthesis of α-aminophosphonic acid derivatives has been achieved by alkylation of the Schiff bases 2, prepared from (1R,2R, 5R)(+) or (1S,2S, 5S)(-) 2-hydroxy 3-pinanone 1 and α-aminomethyl phosphonic acid diethylester. Diastereoisomeric alkylated Schiff bases separated on column chromatography afforded after hydrolytic cleavage enantiomerically pure compounds.

The chemical shift of two-coordinate phosphorus, ii1,2 heterocycles

Abstract: A compilation of the chemical shifts of two-coordinate phosphorus in fully unsaturated cyclic compounds is presented. (Acyclic as well as partly unsaturated cyclic compounds are covered in Part I). Data are arranged according to the ring size and to the neighbours to the phosphorus in the ring. δ31P tends to lower field in the series C. N. P for the neighbouring ring members; the whole range extends roughly from δ31P=470 to 0 with most of the shifts between 300 and 50. Parallels to δ13C and δ15N in heterocycles with CH and N, respectively, in place of P are shown.

SYNTHESIS OF α-HALOGENATED METHANEDIPHOSPHONATES1a, b

Abstract: Methanediphospnonate (MDP) anions can exhibit anti-viral activity, inhibit bone resorption, and act as ligands in radiopharmaceuticals. α-Halo-substitution provides MDP derivatives (XYMDP, where × = H, F, CI or Br; Y = F, Cl or Br) with modified acid-base, steric and other properties. These compounds are conveniently made from the corresponding α-halogenated XYMDP esters (RO)2P(O)CXYP(O)(OR)2. Detailed procedures are given for synthesis of R4 XYMDP for R = Pri and X, Y = H. Cl; Cl, Cl; H, Br; Br, Br; F, Cl; F, Br and Cl, Br in 88–96% yield; for R = Et and X, Y = H, Cl; Cl. Cl; H, Br; Br, Br and Cl, F in 81–94% yield; and for R = Me and X, Y = Cl, Cl and Br, Br in 72–80% yield. NMR data (1H, 31P, 13C. (19F)) are presented for the products obtained. The XYMDP acids (X, Y = H, Cl; Cl, Cl; H, Br; Br, Br; F, Cl; F, Br and Cl, Br) were prepared by HCl hydrolysis of a corresponding ester and characterized as tris(dicyclohexylammonium) salts by elemental analyses and 31P NMR.

Phospho-4-pyrazoles. synthese et etude spectrographique rmn 1h, 31p et 13c

Abstract: 4-Phosphopyrazoles are prepared with good yield by cyclisation of hydrazone phosphorus compounds and ethylortho formiate. The effects of substitution are investigated on the 13C chemical shifts of pyrazole ring. The magnitude of the coupling constant 1 J pc is in good agreement with the hybridization of the phosphorus atom.

31p-nmr-spektroskopischer nachweis von supermesityl-substituiertem triphosphaallyllithium und 2-arsa-1,3-diphosphaallyllithium

Abstract: The compounds 1.3-bis(2,4,6-tri-tert.butylphenyl)triphosphaallyllithium (5) and 1.3-bis(2,4,6-tritert.butylphenyl)-2-arsa-1,3-diphosphaallyllithium (7) are prepared by deprotonation of a phosphino-substituted diphosphene and arsaphosphene, resp. The presence of trans/trans and cis/trans isomers has been proven by 31P-NMR spectroscopy. Die Verbindungen 1.3-Bis(2,4,6-tri-tert.butylphenyl)triphosphaallyllithium (5) und 1.3-Bis-(2,4,6-tri-tert.butylphenyl)-2-arsa-1,3-diphosphaallyllithium (7) werden durch Deprotonierung eines phosphino-substituierten Diphosphens bzw. Arsaphosphens dargestellt. Das Vorliegen von trans/trans und cis/trans-Isomeren wird durch 31P-NMR-Spektroskopie nachgewiesen.

Synthesis and reactions of some 2-thienyl- and 2-thenoyl-derivatives of thiazole and thiadiazoline and their selenium analogs

Abstract: 2-(Thiocyanatoacetyl)thiophene 2 and its selenium analog 3 couple with diazotized anilines and yield 3-aryl-2-imino-5-(2-thenoyl)-2,3-dihydro-1,3,4-thiadiazoles 6 and 3-aryl-2-imino-5-(2-thenoyl)-2,3-dihydro-1,3,4-selenadiazoles 7 respectively. The reactions of both 6 and 7 with nitrous acid, acetic anhydride and benzoyl chloride are described. Azo coupling of 2-amino-4-(2-thienyl)thiazole 17 and its selenazole analog 18 with diazotized anilines yielded the arylazo derivatives 19 and 20 respectively. Reaction of the hydrazidoyl bromide 16 with potassium thiocyanate, potassium selenocyanate, thiourea and selenourea yields 6, 7, 19, and 20 respectively.

Synthese d'indole phosphonates par cyclisation selon fischer d'arylhydrazones phosphonates

Abstract: La cyclisation selon Fischer d'arylhydrazones d'oxo-1,2 et 3 alkylphosphonates permet d'acctderi a divers indole phosphonates 1–5. Les acides phosphoniques correspondants 1′-5′ ont Cgalement ete prepares. Les structures des differents indoles sont confirmees par spectroscopie RMN31P, 1H et 13C. The Fischer cyclization of 1,2,3-oxoalkylphosphonates arylhydrazones into indole phosphonates 1–5 is described. The corresponding phosphonic acids 1′-5′ are also prepared. The structures of these indoles have been determined by 31P, 1H and 13CNMR spectroscopy.

CRYSTAL STRUCTURE OF T-BUTYL PERTHIOPHOSPHONIC ANHYDRIDE, (t-C4H9PS2)2, AND ITS SELENIUM ANALOG (t-C4H9PSe2)2

Abstract: Crystals of the title sulfur compound are orthorhombic, Cmca, with a=9.872 (1), b=9.594 (1), and c=15.488 (1) A, V=1467.0 (4) A3, Z=4, and Dc =1.38 g cm−2. The final refinement using 537 observed reflections for 57 variable gave R=0.025. The non-isomorphous crystals of the selenium analog are also orthorhombic, Cmca, with a=9.300 (1), b=19.724 (1), c=8.064 (1) A, V=1479.1 (4) A, Z=4, and Dc =2.21 g cm−2. Refinement with 48 variables using 447 observed reflections gives R=0.041. In both structures the molecules have 2/m symmetry imposed by the lattice symmetry; the S (or Se) atoms of the central 4-membered ring are located on the rotation axis, and the P, exo S (or Se), and two carbon atoms of the t-butyl group lie on the mirror plane. The central rings are not readily hydrolyzed or oxidized by exposure to air, apparently as a result of steric protection provided by the t-butyl groups.

THE REACTION OF PHOSPHONIUM YLIDES WITH 1,2-BENZO[a]PHENAZINE-8,9-DIONE, NAPHTHO[2,1-b]FURAN-1,2-DIONE, BENZO[b]THIOPHENE-2,3-DIONE AND 1,2,3-INDANTRIONE

Abstract: When 1,2-benzo[a]phenazine-8,9-dione (1), was reacted with two molar amounts of phosphonium ylides (5), the corresponding dialkyl 1,2-dihydrobenzo[a]furo[3,2,h]phenazine-1,2-dicarboxylates (9) were obtained. Moreover, naphtho[2,1-b]furan-1,2-dione (2) and benzo[b]thiophene-2,3-dione (3) were converted by reaction with ylides (5) into alkyl 2-oxonaphtho[2,1-b]furan-1(2H)-ylidene acetate (10) and alkyl (2-oxobenzo[b]thien-3(2H)-ylidene)acetate (11). On the other hand, the spiro-compounds (13) were isolated from the reaction of 1,2,3-indantrione (4) and Wittig reagents (5). The structure of the new compounds 9, 10, 11 and 13 was confirmed on the basis of elemental analysis and spectral studies.

2-METHYLARENO[d]-3-AZATELLUROPHENES

Abstract: 2-6-Dimethylbenzo[d]-3-azatellurophene(22%), 2-methyl-6-tert-butylbenzo[d]-3-azatellurophene (11%), 2-methyl-6-chlorobenzo[d]-3-azatellurophene (31%) and 2-methylnaphtho[2,1-d]-3- azatellurophene (13%) were prepared from 4-methylaniline, 4-tert-butylaniline, and 2-aminonaphthalene, respectively. The yields given in parentheses are overall yields based on the arylamine. For example, equimolar amounts of mercury acetate and 4-aminotoluene were refluxed in methanol for 12 hours. Lithium chloride was added to the mixture to produce 2-amino-5-methylphenyl mercury chloride. Acetylation with excess acetic anhydride gave 2-acetamido-5-methylphenyl mercury chloride in nearly quantitative yield based on aminotoluene. The aryl mercury chloride produced 2-acetamido-5-methylphenyl tellurium trichloride in 40% yield when refluxed with an equimolar amount of tellurium tetrachloride in acetic acid. Reduction with excess sodium sulfide gave bis(2-acetamido-5-methylphenyl) ditelluride in 94% yield, which was isola...

The chemistry of 3-aminothioacrylamides; part ii: 3-aminothioacrylamides as useful synthons in organic synthesis

Abstract: 3-Aminothioacrylamides are a class of organic sulfur containing compounds that are easily available and exhibit polyfunctional reaction behaviour. They can be used widely in the synthesis of a variety of heterocyclic and open chain compounds. The synthetic utility of 3-aminothioacrylamides can be further extended if additional functionalities are incorporated.

Molekülstruktur eines stabilen pentaoxy-spirophosphorans mit phospor als brückenkopfatom zwischen einem sechsgliedrigen und einem fünfgliedrigen ring

Abstract: The crystal and molecular structure of the trigonal-bipyramidal pentaoxy-spirophosphorane 1 reveals the smaller influence on the stereochemistry at phosphorus of the six-membered compared with five-membered rings. The large difference between the two axial P[sbnd]O bonds (161.6 and 171.0 pm) and between the three equatorial P[sbnd]O bonds (range 157.7–163.6 pm) is ascribed to the influence of the CF3-groups on the electronegativity of the oxygen atoms.

Lithium organyl-polychalcogenolates

Abstract: Lithium organyl-selenolates, RSeLi or tellurolates, RTeLi insert further equivalents of chalcogens with formation of selenenyl-selenolates, RSeSeLi or tellurenyl-tellurolates, RTeTeLi (R=Me, n-Bu, s-Bu, t-Bu, Ph). Mixed anions are only formed if the chalcogen insertion order corresponds with an increase of electronegativity, i.e.: RTeSeLi, RTeSLi, RSeSLi and n-BuTeSeSLi. All species have been characterized by 77-Se and 125-Te NMR-spectroscopy. Tellurenyl-tellurolates and tellurenyl-selenolates are stable at room temperature, selenenyl-selenolates and chalcogenyl-thiolates disproportionate. The chemical integrity of the chalcogenyl-chalcogenolates was checked by methylation with methyl triflate. The formed organyl-methyl-dichalcogenides exhibit symmetrization equilibria that are also obtained by mixing the symmetric compounds. Oxidation of tellurenyl-selenolates affords di(organyl-tellurenyl) selenides, (RTe)2Se (R=Me, n-Bu, t-Bu, Ph, p-MeC6H4, 2-thienyl) and (RTe)2Se2 for R=(Me3Si)3C. In solution...

Heterocycles from nitrile oxides: synthesis and reactions of 2-thienoylhydroxamoyl chloride

Abstract: Nitroso derivatives of imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine and imidazo[1,2-a]pyrazine were obtained in good yields by the action of 2-thienoylhydroxamoyl chloride (2) on 2-aminopyridines, 2-aminopyrimidine and 2-aminopyrazine, respectively. Benzotriazine, benzothiadiazine and quinazoline were obtained from 2 via its reactions with o-phenylendiamine, o-aminothiophenol and methylanthranilate, respectively. 2 was treated with ethylenic and acetylenic dipoloraphiles to afford 3-thienoylisoxazolines and isoxazole, respectively. The structures of the products were assigned and confirmed on the basis of their elemental analyses, spectral data and alternative synthesis wherever possible.

Reactions of chlorosulfonylbenzylidene hydantoins

Abstract: 5-(Benzylidene- and o-chlorobenzylidene-) and cinnamylidene-hydantoins reacted with chlorosulfonic acid to give the corresponding p-sulfonyl chlorides (1, 35, 44). These were converted into 49 derivatives by reaction with amines, hydrazines and azide ion. 5-(o-chlorobenzylidene)hydantoin appeared to exist as two geometric isomers. The NMR spectra indicated that alkylation of the benzylidenehydantoins (3, 4, 38) occurred preferentially at the N(3)-position. The spectral data of the compounds are briefly discussed, together with preliminary biological screening results against insects, weeds and fungi.

THERMOCHROMIC MOLECULES WITH BONDS OF Se OR Te AND Sb OR Bi

Abstract: The syntheses and properties of stibino or bismuthino selenides or tellurides of the types R2EE'R, (R2E)2E'R, RE(E'R)2; E = Sb, Bi; E' = Se, Te; R = CH3, C2H5, C6H5 are described Reversible change of color with variation of temperature (thermochromism) is observed in the case of (CH3)2SbTeCH3, (C2H5)2SbTeCH3, [(CH3)2Sb]2Se and [(CH3)2Sb]2Te

Hofmann elimination reaction with phosphorus containing alkylammonium salts

Abstract: Ethylammonium phosphite salts, formed by alkyl transfer from dialkyl phosphites to tertiary amines, undergo a Hofmann elimination of ethylene.

SYNTHESIS OF SOME 4,5,6,7-TETRATHIOCINO [1,2-b:3,4-b′] DIIMIDAZOLYL-1,3,8,10-TETRASUBSTITUTED-2,9-DITHIONES AND CRYSTAL STRUCTURE OF THE TETRAETHYL DERIVATIVE

Abstract: A new unexpected molecule has been obtained by reacting 1,3-disubstituted-imidazolidinetrione-2-thio derivatives (R=Methyl, Ethyl, Phenyl, o-Tolyl) with Lawesson's reagent. The X-ray structure of a crystal of this material (R=Ethyl) demonstrated that the title compound with an eight-membered ring composed of four S and four C-atoms was formed. The crystals are monoclinic, space group C2/c, a=18.071(4), b=9.447(2), c=14.952(3)A, β=126.14(2)°, U=2061.4(9)A3, Z=4. Solution and refinement of intensity data gave final residuals of R=0.0354 and R w=0.0426 using 1090 observed reflections [I ≥ 2σ(I)]. In the molecule the eight membered ring adopts a chair conformation; in the [sbnd]C[sbnd]C[sbnd]C[sbnd]C[sbnd]moiety the C(3)[sbnd]C(3′) bond length is shorter than that of a single bond and the imidazolidine rings are not planar.

Chalcogenide photovoltaic solar cells of special interest

Abstract: A brief review is given of those semiconducting selenides and tellurides that appear suitable for the absorber layer of a photovoltaic solar cell, with energy gaps in the range 1 to 2 eV. Furthermore, to obtain a lower cost cell, the semiconductor is also required to be used in the form of a thin polycrystalline film, necessitating a high optical absorption coefficient in the material. At the present time the two best chalcogenides meeting these requirements are the compounds CuInSe 2 and CdTe, both of which have been used in polycrystalline thin film structures with CdS, as the window layer, yielding conversion efficiencies of over 10%. They have also demonstrated very good chemical stability.

Synthese d'arylamino-1 ou-3 oxo-2 propylphosphonates. passage aux indole phosphonates selon bischler

Abstract: La synthese d'indole phosphonates 3, 4, 4′ par cyclisation selon Bischler d'arylamino-1 ou-3 oxo-2 propylphosphonates 1 et 2 (Fig. 8) est decrite. Deux nouveaux reactifs sont utilises pour acceder a ces arylaminocetones: les chloro-1 et chloro-3 methoxycarbonylhydrazono-2 propylphosphonates 6 et 10; ces composes subissent en milieu basique une elimination 1, 4 de chlorure d'hydrogene et donnent des azoenes qui additionnent les anilines selon Michael. Les arylaminohydrazones obtenues sont transformees en arylaminocetones par traitement par une solution aqueuse de TiCl3 ou par une reaction d'echange avec l'acetone en milieu chlorhydrique. The synthesis of indole phosphonates 3, 4, 4′ by Bischler cyclization of 1-or 3-arylamino-2-oxopropylphosphonates 1 and 2 (Fig. 8) is described. Two new reagents are used to prepare the arylaminoketones: the 1-chloro and 3-chloro-2-methoxycarbonylhydrazonopropylphosphonates 6 and 10; these compounds undergo base-catalysed 1,4 elimination of hydrogene chloride lead...

RADIKALIONEN 801,2 MEHRFACH THIADIAZOL-ÜBERBRÜCKTE BENZOL- UND P-BENZOCHINON-RADIKAL- ANIONEN UND IHRE Cr-, Mo- UND W-PENTACARBONYL-KOMPLEXE

Abstract: Stable radical anions of bis(thiadiazolo)-p-benzoquinone as well as of bis-and tris(thiadiazolo)benzene derivatives form on one-electron reduction using potassium/[2.2.2.] cryptand in THF solution. According to the assigned ESR spectra, their electron-rich sulfur centers exhibit especially large spin populations. On addition of THF soluble alkalimetal salts, the ESR signals vanish, whereas with metal hexacarbonyls Me(CO)6 paramagnetic mono- (Me=W) and di(metalpentacarbonyl) (Me=Cr, Mo, W) complexes result, for which HMO-McLachlan calculations suggest preferred coordination at the N centers of the same thiadiazol bridge. Stabile Radikalanionen von Bis(thiadiazol)-p-benzochinon sowie von Bis- und Tris(thiadiazol)-benzol-Derivaten entstehen bei Einelektronen-Reduktion mit Kalium/[2.2.2.]-Kryptand in THF Losung. Nach den zugeordneten ESR-Spektren weisen ihre elektronenreichen Schwefel-Zentren besonders groβe Spinpopulationen auf. Bei Zugabe THF-loslicher Alkalimetall-Salze verschwinden die ESR-Signal...

α-DICETO DIPHOSPHONATES ET HYDROXYMETHYLENE TETRAPHOSPHONATES SYNTHÈSE, STRUCTURE ET HYDROLYSE

Abstract: Synthesis of methyl esters 3–8 or cyclic esters 3′–8′ of diketo-diphosphonates having n(CH2) are studied. These compounds lead to the corresponding symmetric 3a–8a and 3′a–8′a or disymmetric 3,3′a–8,8′a tetraphosphonates which are isomerized to the phosphates-phosphonates structures 4b–8b and 4′b–8′b. The hydrolysis reactions are also observed.

Organische phosphorverbindungen 841. herstellung, eigenschaften und biologische wirkung von hydrazinomethyl-phosphon- und -phosphinsäuren und derivaten

Abstract: The synthesis and the chemical, physical, spectral and biological properties of hydrazinomethyl-phosphonic- and -phosphinic acids and derivatives, i.e. hydrazino-N-alkoxycarbonyl-N'alkylene-O,O-dialkoxyphosphonates, 2, -phosphinates, 3, hydrazinomethyl-O,O-diethylphosphonate, 4a. hydrazino-methylphosphonic acid 4b, hydrazinomethyl-O-isobutyl-methylphosphinate, 4c, hydrazinomethyl-methylphosphinic acid, 4d, and hydrazino-N-alkoxycarbonyl-N'-methylphosphonic acids, 5, are described and the reactions of these compounds with acyl chlorides, bromoacetates, and isocyanates are reported. Several of these compounds and, in particular, the chloroacetyl, 7, and dichloro-acetyl-derivatives, 8 and 9, show a good safening effect against the phytotoxic action of chloroacetanilide herbicides.

Heterocyclization of 1,2,4- and 1,3,4-alkatrienylphosphonic dichlorides with electrophilic reagents

Abstract: By the reaction of 1,2,4- and 1,3,4-alkatrienylphosphonic dichlorides with sulfuryl, sulfenyl and selenenyl chlorides, the different P-containing heterocyclic compounds have been prepared. The obtained heterocycles contained one or two chorine atoms at phosphorus which have great reactivity and can change with another functional groups.

Synthesis of some phosphorus derivatives of cardanol

Abstract: The synthesis of some phosphonates obtained by reaction of cardanol and 3-n-pentadecylphenol with pentavalent phosphorus chlorides containing oxygen or sulfur atom is reported.

Heterocyclic phosphonium salts by reaction of dimethyl(1,2-alkadienyl)-phosphine oxides with electrophilic reagents

Abstract: Salts of 2,5-dihydro-1,2-oxaphosphole have been prepared by reaction of dimethyl(1,2-alkadienyl)phosphine oxides with halogens, sulfenyl and selenenyl chlorides. The essential influence of tertiary carbenium ions for realization of oxaphospholic cyclization of phosphorylated allenes has been established.

Substituent effects on the 31p, 13c, and 1h nmr chemical shifts of substituted diphenyl 1-phenylamino-1-phenylmethanephosphonates and their anions

Abstract: For a series of thirty-five novel diphenyl 1-phenylamino-1-phenylmethanephosphonates, substituted in the meta and para positions on the anilino and/or aryl ring, 31P chemical shifts show a good linear correlation with Hammett σn and Taft σ° parameters, the 31P nucleus being better shielded in the case of electron withdrawing substituents The same pattern is observed for the phosphonate anions, except when para phenyl substituents can interact with the phosphorus atom by direct resonance This inverse relationship is due to a field effect of the substituent dipole which polarizes π-electron clouds in the molecule A corresponding shift in π-electron density is likewise observed for 13C resonances of the two diastereotopic phenoxy groups, the phenylamino and phenyl moieties Vicinal CH-NH coupling is shown to be dependent on the rate of NH proton exchange as influenced by resonance, temperature and solvent effects

Organic disulfides and related substances. 48. cyclic di- and trisulfides based on 1,4-dithiols1

Abstract: Based on 1,4-dithiols, the seven-membered cyclic trisulfide 1,5-dihydro-2,3,4-benzotrithiepin (3), the nonbenzenoid counterpart (17), related oxides, and open-chain analogs were investigated. The m...